A cDNA library was constructed from the brains of 18 day old rats, and was screened with a synthetic DNA probe to yield clones representing myelin basic protein (MBP). One 1.9 kb clone was sequenced and found to encode the 14 kd MBP. Using this clone as a hybridization probe, cosmid clones from a library of wild type mouse DNA were selected and characterized. One clone was shown to carry five exons which encode 14 kd MBP, distributed over a 32 kb region. A sixth exon was detected with a synthetic DNA probe, and was found to encode the 41 amino acids which distinguish 18.5 kd from 14 kd MBP. The 5' end ot the gene was mapped with S1 nuclease protection and primer extension experiments to a position 47 bp 5' of the initator codon for MBP synthesis. It was shown that the gene cloned is probably the only MBP gene in the mouse genome.
\r\n\r\nCloned DNAs were used to analyze the MBP gene and its expression in the myelin deficient mutant mouse shiverer. It was shown that a deletion has removed five out of six MBP exons, leaving only the 5'-most exon and 13 kb of the first intervening sequence. The deletion completely prevents expression of normal 2.1 kb MBP mRNAs, but a 16-fold lower number of transcripts are observed which initiate correctly at the 5' end of the first exon, are not correctly spliced, and are rarely polyadenylated. If translated, they would direct synthesis of a 61 amino acid peptide containing the first 56 amino acids of MBP. The MBP gene was mapped to mouse chromosome 18 by hybridization of MBP probes with DNA from Chinese hamster-mouse hybrid cell lines, showing it to be linked to the shiverer mutation. It is proposed that the partial deletion of the MBP gene is the primary lesion of the shiverer mutation.
", "doi": "10.7907/4d7s-zs52", "publication_date": "1985", "thesis_type": "phd", "thesis_year": "1985" }, { "id": "thesis:10895", "collection": "thesis", "collection_id": "10895", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05162018-092739245", "primary_object_url": { "basename": "Green_SH_1982.pdf", "content": "final", "filesize": 92489877, "license": "other", "mime_type": "application/pdf", "url": "/10895/1/Green_SH_1982.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Genetic Studies of Neuronal Development in Drosophila melanogaster", "author": [ { "family_name": "Green", "given_name": "Steven Haym", "clpid": "Green-Steven-Haym" } ], "thesis_advisor": [ { "family_name": "Lewis", "given_name": "Edward B.", "clpid": "Lewis-E-B" } ], "thesis_committee": [ { "family_name": "Lewis", "given_name": "Edward B.", "clpid": "Lewis-E-B" }, { "family_name": "Konopka", "given_name": "Ronald J.", "clpid": "Konopka-Ronald-J" }, { "family_name": "Meyerowitz", "given_name": "Elliot M.", "orcid": "0000-0003-4798-5153", "clpid": "Meyerowitz-E-M" }, { "family_name": "Revel", "given_name": "Jean-Paul", "clpid": "Revel-J-P" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "The projections into the central nervous system (CNS) of several wild-type and genetically ectopic sensory structures were studied by cobalt filling or silver staining and compared for the purpose of determining what factors guide the growth of the sensory axons. The head bristles all arborize in a similar fashion in the subesophageal ganglion although they reach the target by three different routes depending on their position on the head. This arborization is L-shaped with a longitudinal branch and a medially directed branch that crosses the midline. The antennal projection consists of an olfactory lobe component, organized into glomeruli, and an antennal mechanosensory component which can be further subdivided into three branches, the anteriormost of which is identical to the head bristle projection. The tarsi all have similar U-shaped projections into their segment's neuromere with no ascending, descending or contralateral branches.
\r\n\r\nAxons of ectopic thoracic bristles on the head may enter the brain or the optic lobes. The routes into the brain taken by the ectopic bristles were initially like those of the normal head bristles but were followed for greater or lesser distances and the region of the subesophageal ganglion that is the target of the head bristles was seldom reached. The terminal arborizations of the ectopic bristle axons were generally irregular regardless of where they were: in the subesophageal ganglion, brain or optic lobes. They resembled neither their normal arborizations in the ventral ganglion nor those of the local head sensilla in the brain.
\r\n\r\nAxons from antennal legs have a pattern of projection grossly similar to that of wild-type antennae in that the same regions of neuropil were innervated. The non-olfactory lobe components of the antennal leg projection were like those of the antenna. However, the arborization in the olfactory lobe was chaotic and there were adventitious projections from the lobe into adjacent neuropil, particularly the subesophageal ganglion. Some elements of these adventitious projections in the subesophageal ganglion were found consistently in almost every preparation. No element of the projection resembled the leg projection in the ventral ganglion.
\r\n\r\nThe axons of ectopic sensilla can reach a normal target if the distance to it from the new location is sufficiently small: axons from abdominal legs in bxd mutants terminate in normal metathoracic leg sensory neuropil and the axons of antennae misplaced as a result of the mutation ant can enter normal antennal targets.
\r\n\r\nIn summary, axons of ectopic sensilla can't reach their normal targets if they enter the CNS far from those targets which suggests that there are no long range cues for guidance of sensory axons. In the \"foreign\" part of the CNS the axons of ectopic sensilla do not make projections that resemble their normal ones. They initially take routes characteristic of sensilla in their new location but do not follow them consistently. The exception, antennal leg mechanosensory projections, is likely to be a result of a homology between antennal and leg mechanosensory sensilla. These results suggest the following: insect sensory neurons reach their targets mainly by following local and not long-range cues. The growth of these axons is constrained to specific tracts and it is by these that they are guided over long distances to their targets. Tracts recognized by the axon can be recognized at any point and, as the present study shows, this recognition is required not only at the point of entry but continuously, all along the tract, for guidance of the axon. Guidance by the tract appears to depend on an affinity between the axon and the tract that may also exist between axons and tracts of their segmental or functional homologues. Since axons in foreign neuropil have irregular arborizations characteristic neither of their normal ones nor of those of the local sensilla, the arborization pattern is not a result of an internal branching program alone nor of the axon's milieu directing the branching but must depend on a specific interaction between the axon and its target.
\r\n\r\nThe leg motorneurons were identified and described after HRP backfilling from cut legs. The pattern of their positions differs from segment to segment. The bithorax mutations transform the metathoracic pattern into a mesothoracic pattern, paralleling their effect on the epidermis.
", "doi": "10.7907/3h8z-9176", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:10891", "collection": "thesis", "collection_id": "10891", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05152018-142224321", "primary_object_url": { "basename": "Jennings_KR_1982.pdf", "content": "final", "filesize": 71550175, "license": "other", "mime_type": "application/pdf", "url": "/10891/1/Jennings_KR_1982.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Studies of Excitability in a Model Peptidergic System: The Roles of Cyclic AMP, Protein Phosphorylation and Serotonin During Afterdischarge in the Bag Cell Neurons of Aplysia californica", "author": [ { "family_name": "Jennings", "given_name": "Kent Richard", "clpid": "Jennings-Kent-Richard" } ], "thesis_advisor": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "thesis_committee": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Brockes", "given_name": "Jeremy P.", "orcid": "0000-0002-3395-5159", "clpid": "Brockes-Jeremy-P" }, { "family_name": "Hudspeth", "given_name": "A. James", "clpid": "Hudspeth-A-J" }, { "family_name": "Konopka", "given_name": "Ronald J.", "clpid": "Konopka-Ronald-J" }, { "family_name": "Lazarides", "given_name": "Elias", "clpid": "Lazarides-E" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "The polypeptide hormone-secreting bag cell neurons from the abdominal ganglion of Aplysia can be induced to fire repetitively when triggered by a brief electrical stimulus to the afferent pathway. This thesis investigates the mechanism of this afterdischarge by employing biochemical, pharmacological and electrophysiological approaches.
\r\n\r\nThe description of bag cell afterdischarge, its modulation by the transmitters serotonin and dopamine and evidence for the role of cyclic AMP in the genesis of afterdischarge is presented in Chapter 1. Bag cell afterdischarge is shown to be inhibited by the application of serotonin and lengthened by the application of dopamine or the methylxanthine phosphodiesterase inhibitors. Cyclic AMP undergoes a 2-3 fold increase in the bag cell clusters during an electrically-stimulated afterdischarge but not in matched controls where equivalent electrical stimulation did not elicit afterdischarge. As further evidence for a role for cyclic AMP in the genesis of afterdischarge, afterdischarges were obtained in unstimulated preparations by the extracellular application of the cyclic AMP analogues, 8-benzylthio-cyclic AMP and 8-methylthio-cyclic AMP.
\r\n\r\nChapter 2 describes protein phosphorylation in bag cell tissues under a number of different conditions. The presence of an endogenous, cyclic AMP-dependent protein kinase activity is demonstrated in crude membranes prepared from bag cells and the substrate specificity for this activity is shown to be similar to that of protein kinase catalytic subunit prepared from bovine heart. Increases in phosphorylation of a 33,000 dalton and 21,000 dalton phosphoprotein are shown to occur during electrically-stimulated afterdischarge in bag cells. The 21,000 dalton substrate is shown to be apparently specific to bag cell tissues and an amino acid composition and partial amino acid sequence of this protein is presented.
\r\n\r\nChapter 3 presents evidence that serotonin, within the physiological range reported by other workers for Aplysia (0.1-1.0 \u03bcM) brings about a rapid inhibition of an ongoing afterdischarge. This inhibition is antagonized by the stereospecific blocker of serotonin action, D-butaclamol but not its inactive isomer, L-butaclamol. Serotonergic inhibition is shown to be associated with decreased bag cell action potential duration and height and an increased threshold to spike generation. Evidence is presented that the second, calcium-dependent phase of bag cell afterdischarge is most sensitive to the action of the transmitter and that the potassium channel blocker, tetraethylammonium can overcome serotonin's inhibitory effect. This raises the possibility that serotonin may cause inhibition of bag cell afterdischarge by increasing potassium conductance. The possible functional role of serotonin inhibition of egg-laying is discussed.
", "doi": "10.7907/8k0z-ft54", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:11843", "collection": "thesis", "collection_id": "11843", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10222019-143344602", "type": "thesis", "title": "Behavioral Neurogenetic Studies of a Circadian Clock in Drosophila melanogaster", "author": [ { "family_name": "Orr", "given_name": "Dominic Ping-Yim", "clpid": "Orr-Dominic-Ping-Yim" } ], "thesis_advisor": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Konopka", "given_name": "Ronald J.", "clpid": "Konopka-Ronald-J" } ], "thesis_committee": [ { "family_name": "Brokaw", "given_name": "Charles J.", "clpid": "Brokaw-C-J" }, { "family_name": "Konopka", "given_name": "Ronald J.", "clpid": "Konopka-Ronald-J" }, { "family_name": "Konishi", "given_name": "Masakazu", "clpid": "Konishi-M" }, { "family_name": "Hopfield", "given_name": "John J.", "clpid": "Hopfield-J-J" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "The circadian clock controlling the locomotor activity of the adult fruitfly, Drosophila melanogaster, is studied in one wild-type and five clock mutant strains. Locomotive activity of individual flies are monitored using arrays of infra-red beams and detectors. It is found that the temperature compensation mechanism is intact in the mutants And and ClkK06, is slightly defective in the mutant pers and is grossly defective in the mutants perl1 and perl2. In the pers and perl1 mutants, this defect is enhanced when both eyes and major parts of both optic lobes are eliminated by a genetic mutation (sine oculus). The inter-individual variation of periods in a strain is found to increase much more than linearly with the average period of the same strain. The interaction between the And and the per loci and that between the And and ClkK06 loci are found to be either very weak or non-existent (effects of mutations additive), whereas the interactions among the various alleles in the per locus are found to be strong (effects of mutations non-additive).
\r\n\r\nTen 'Phase Resetting Curves' (PRC) obtained with saturating light pulses for six strains of flies at various temperatures are presented. All the ten cases exhibit basically 'type-1' resetting behavior (average slope = 1). Comparisons of the PRC's for pers, perl1 and wild-type at 17\u00b0C suggest that the mutations pers and perl1 change the period of the circadian clock by differentially shortening and lengthening, respectively, the duration of the 'subjective day' phase of the oscillation. Comparisons between the PRC's for pers at 17\u00b0C, 22\u00b0C, and 25\u00b0C and comparison between the wild-type PRC's at 17\u00b0C and 22\u00b0C do not reveal major changes in the temporal structure of these two circadian clocks over the stated temperature ranges.
\r\n\r\nThe responses of one wild-type and five mutant circadian clocks to sustained dim light of the range 5 x 10-4 lux to 50 lux at 22\u00b0C are studied. In each strain, a critical 'window' of light intensity is found within which a variety of unstable clock features, including arrhythmia, are observed. The light intensity at which this critical window occurs in each of the mutant is 5 to 10 times lower than that in the wild-type. Responses from a ERG-defective mutant (norpA) are found to be qualitatively, but not quantitatively, similar to that of the wild-type. Responses from an eyeless and ocelli-less mutant (sine oculus) indicate that both period changes and arrhythmicity can be elicited by light in the absence of the compound eyes and ocelli. However, the sharp dependence of the occurences of these phenomena on light intensity is lost in this mutant.
\r\n\r\nArguments are presented to suggest that none of the four mutations -- And, ClkK06, pers, and perl1 -- cause changes of period by mimicking the effects of tonic light on the Drosophila circadian system.
\r\n\r\nThe phase resetting curves (PRC) and the dim light responses described above are found to be incompatible with a particular model of the Velocity Response Curve (VRC) theory to inter-relate the phasic to tonic effects of light, in which the tonic effect of light is assumed to be the result of a summation of the effects of a contiguous series of single Light pulses, taking into account adaptation.
", "doi": "10.7907/wp4e-5054", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:10910", "collection": "thesis", "collection_id": "10910", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05172018-103149078", "primary_object_url": { "basename": "Smith_RF_1982.pdf", "content": "final", "filesize": 59863537, "license": "other", "mime_type": "application/pdf", "url": "/10910/1/Smith_RF_1982.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Genetic Analysis of the Circadian Clock System of Drosophila melanogaster", "author": [ { "family_name": "Smith", "given_name": "Randall Forrest", "clpid": "Smith-Randall-Forrest" } ], "thesis_advisor": [ { "family_name": "Konopka", "given_name": "Ronald J.", "clpid": "Konopka-Ronald-J" }, { "family_name": "Owen", "given_name": "Ray David", "clpid": "Owen-R-D" } ], "thesis_committee": [ { "family_name": "Owen", "given_name": "Ray David", "clpid": "Owen-R-D" }, { "family_name": "Konopka", "given_name": "Ronald J.", "clpid": "Konopka-Ronald-J" }, { "family_name": "Lewis", "given_name": "Edward B.", "clpid": "Lewis-E-B" }, { "family_name": "Mitchell", "given_name": "Herschel K.", "clpid": "Mitchell-H-K" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "The circadian rhythm phenotypes of eight chromosome aberrations with a breakpoint in the region of the per locus (3B1-2) of Drosophila melanogaster have been analyzed. Two duplications and five deficiencies with a 3B1-2 breakpoint produce either a wild-type (approx. 24-h period) or an arrhythmic clock phenotype while one translocation with a 3B1-2 breakpoint, T(1;4)JC43, produces locomotor-activity rhythms with either very-long periods (31-39 hr), rhythms that grade into arrhythmicity, or completely arrhythmic phenotypes. The clock phenotypes of 3B1-2 chromosome aberrations suggest that arrhythmicity results from the total lack of per function while long-period phenotypes result from a reduction, but not complete elimination, of per activity. An extensive complementation analysis of 3B1-2 chromosome aberrations and per mutant alleles provided no compelling evidence for genetic complexity at the per locus. This is in contrast to the report of Young and Judd (1978). Analysis of both the locomotor-activity and eclosion phenotypes of 3B1-2 chromosome aberrations did not uncover differences in the genetic control of these two rhythms.
\r\n\r\nThe normal 24-h period of the circadian rhythms of locomotor activity and eclosion of Drosophila is shown to be altered by changes in per gene dosage. Females with only one dose of per+ or pers (the 19-h short-period mutant allele) or perl (the 29-h long-period mutant allele) have periods which are about 1-2 h longer than the corresponding females with 2 doses. Females with 3 doses of per+ and males with 2 doses of per+ or pers have periods which are 1/2 to 1 h shorter than the corresponding individuals without the extra dose. Males with three per+ doses have periods which are about 1.5 h shorter than wild-type males; additional per+ doses do not shorten period further. The observation that decreased per dosage lengthens period while increased dosage shortens period suggests that the long- and short-period mutations alter period by respectively decreasing and increasing per gene or gene product activity. The per+ dosage results and the complementation behavior of pers indicate that the hypermorphic phenotype of pers results from increased activity of the pers gene product rather than an overproduction of per+ product. This is the first report of such a mutant action in Drosophila.
\r\n\r\nBy screening mutagenized sex-linked and autosomal stocks for ones in which the normal period or phase of the circadian rhythm of eclosion (adult emergence) has been altered, a new X-linked clock mutant has been isolated which lengthens the normal 24-h period of both the the eclosion and adult locomotor-activity rhythms to about 25.5 h. This mutant, which we have named Andante (And), is not an allele of the per locus; recombination and deficiency mapping has placed the Andante locus at a separate site between polytene chromosome bands 10E2 and 10F1 (tentatively at 10E3, just proximal to the m-dy complex at 10E2-3). Andante, like all of the per mutant alleles, has a semi-dominant effect on period. The eclosion rhythm of Andante, like wild-type, has a low-amplitude (Type 1) phase-resetting response to light pulses, but compared to wild-type the Andante phase-resetting curve (PRC) is lengthened by 1-2 h per cycle.
", "doi": "10.7907/9rwg-p020", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:3806", "collection": "thesis", "collection_id": "3806", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09272005-141028", "type": "thesis", "title": "Biochemical and Immunohistochemical Studies of the Egg-Laying Hormone of Aplysia californica: Purification, Primary Structure, Neurosecretion and Morphological Distribution", "author": [ { "family_name": "Chiu", "given_name": "Arlene Yuen-Chin", "clpid": "Chiu-Arlene-Yuen-Chin" } ], "thesis_advisor": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "thesis_committee": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Hudspeth", "given_name": "A. James", "clpid": "Hudspeth-A-J" }, { "family_name": "Lazarides", "given_name": "Elias", "clpid": "Lazarides-E" }, { "family_name": "Mitchell", "given_name": "Herschel K.", "clpid": "Mitchell-H-K" }, { "family_name": "Brockes", "given_name": "Jeremy P.", "orcid": "0000-0002-3395-5159", "clpid": "Brockes-Jeremy-P" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "Egg-laying behavior in Aplysia californica can be triggered by the introduction of a neuropeptide, the Egg-Laying Hormone (ELH) into the circulation. ELH is synthesized by the neurosecretory bag cells of the abdominal ganglion and released when these neurons are induced to fire repetitively. In this thesis, biochemical and immunohistoehemical techniques have been employed to study the primary structure, release and distribution of ELH in the nervous system of Aplysia.
\r\n\r\nThe purification of ELH to homogeneity from extracts of bag cell clusters, and the analysis of its primary structure are discussed in Chapter 1. A 100-fold enrichment of bioactive material was obtained by cation exchange chromatography (Sephadex SP C25) followed by gel filtration (BioRad P-6). This purified material was determined to be homogeneous by four lines of analysis: (i) SDS polyacrylamide gel electrophoresis, (ii) isoelectric focussing, (iii) microsequence analysis, and (iv) comparison of the amino acid compositions from acid hydrolysis and from microsequence data. ELH is a 36 amino acid, basic peptide with a calculated molecular weight of 4385 and an apparent isoelectric point of 9.0-9.2. Its amino acid sequence was determined as:
\r\n\r\nH-lle-Ser-Ile-Asn-Gln-Asp-Leu-Lys-Ala-Ile-Thr-Asp-Met-Leu-Leu-Thr-Glu-Gln-lleArg-Glu-Arg-Gln-Arg-Tyr-Leu-Ala-Asp-Leu-Arg-Gln-Arg-Leu-Leu-Glu-Lys-OH
\r\n\r\nChapter 2 demonstrates the release of ELH, identified by molecular weight, pI and bioactivity, when bag cell clusters afterdischarge in vitro. During such synchronous and prolonged electrical activity, bag cell clusters, which have been pulsed in 35S-Met, secrete at least four labeled presumed peptides of different molecular weights. One of these comigrates with 3H-Leu labeled, purified ELH on gel filtration chromatography and causes egg laying when injected into a test animal. This material also comigrates with 3H-ELH on isoelectrifocussing gels. A second released peptide has a molecular weight of approximately 5-6 K and a pI of 4.8; its function, and the functions of the other released molecules, are unknown.
\r\n\r\nIn order to study the distribution of ELH in the nervous system of Aplysia, antibodies were generated against the purified neuropeptide, coupled to a carrier molecule, thyroglobulin (Tg). Immune sera, enriched for anti-ELH antibodies by passage through an affinity column to remove antibodies which bound to Tg, was used for localizing ELH-like immunoreactivity in frozen sections of Aplysia ganglia. These results were discussed in Chapters 3 and 4.
\r\n\r\nWhen sections of the abdominal ganglion were stained by the PAP method for ELH, all neurons within the bag cell clusters were found to be immunoreactive. Except for occasionally displaced bag cells, all neurons within the ganglion remained unreactive, reflecting the specificity of the antiserum. Immunopositive processes from bag cells proliferate in the vascularized connective tissue capsule which serves as a neurohemal organ facilitating release of neurohormones. Some processes form a spiralling cuff around the nerve trunks of the pleuro-visceral connective and the vulvar nerves; others invade the ganglion in association with connective tissue septa which form partitions between groups of neurons. Immunoreactive fibers with varicosities are also found within the neuropile and the commissure between the two hemiganglia. This light microscopic visualization of the bag cell neuroendocrine system provides morphological support for the model of local hormone action of ELH upon other neurons in the abdominal ganglion. The immunoreactivity of all neurons within the clusters provides the strongest evidence to date of the homogeneity of the bag cell population.
\r\n\r\nAntibodies generated against ELH from A. californica selectively stained the bag cell systems of three other species of Aplysia - A. braziliana, A. vaccaria and A. dactylomela - which also share cross bioactivity. It is likely that receptor binding sites and antigenic determinants are conserved in their ELHs.
\r\n\r\nThe fourth chapter describes the organization of cells and fiber tracts with ELH-like immunoreactivity, endogenous to the head ganglia. Each pleural ganglion has 1-5 immunopositive somata which are strikingly similar to bag cells in cell and nuclear sizes, process morphology and location. These similarities, coupled with the close developmental association of the pleural and abdominal ganglia, suggest a common heritage for both populations of ELH+ cells.
\r\n\r\nThe ELH immunoreactive system in the cerebral ganglion consists of two laterally located clusters of small cells on the dorsal surface of the ganglion and extensive fiber tracts throughout the neuropile. The nature of immunoreactive molecules and the function of these systems within the cerebral and pleural ganglia are unknown. However, perfusion of ELH is known to induce long-term changes in the electrical activity of head ganglia neurons in vitro, and some of these changes may be linked to the suppression of feeding and locomotion during egg laying. The presence of these immunopositive systems in the pleural and cerebral ganglia raises the possibility that ELH target neurons in head ganglia may respond to local sources of ELH or ELH-like molecules.
", "doi": "10.7907/50RT-EZ43", "publication_date": "1981", "thesis_type": "phd", "thesis_year": "1981" }, { "id": "thesis:18370", "collection": "thesis", "collection_id": "18370", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:02172026-214230970", "primary_object_url": { "basename": "Stuart_DK_1978.pdf", "content": "final", "filesize": 36944860, "license": "other", "mime_type": "application/pdf", "url": "/18370/1/Stuart_DK_1978.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Neurosecretion of the Polypeptide Egg-Laying Hormone (ELH) from the Bag Cells, Neuronal Sites of Action of ELH, and Circadian Release of Polypeptides from the Eye of Aplysia californica", "author": [ { "family_name": "Stuart", "given_name": "Duncan Knight", "clpid": "Stuart-Duncan-Knight" } ], "thesis_advisor": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "thesis_committee": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Mitchell", "given_name": "Herschel K.", "clpid": "Mitchell-H-K" }, { "family_name": "Hudspeth", "given_name": "A. James", "clpid": "Hudspeth-A-J" }, { "family_name": "Konishi", "given_name": "Masakazu", "clpid": "Konishi-M" }, { "family_name": "Owen", "given_name": "Ray David", "clpid": "Owen-R-D" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "The thesis is about the neurosecretion of Aplysia peptides and demonstrates\r\nthat one of them acts directly upon the nervous system. Such neuronal\r\neffects of neurosecretory substances may prove to be a general phenomenon; this is\r\ndiscussed in the introduction.
\r\n\r\nIn chapter 1, radiolabeled peptides released from electrically active bag\r\ncell neurons in isolated bag cell clusters were compared with the polypeptide egg-laying\r\nhormone (ELH), 6,000 daltons, pl 9.0-9.3, as purified from homogenates of\r\nbag cell clusters. A labeled peptide which is selectively released from electrically\r\nactive bag cell clusters comigrates with ELH from cluster homogenates on P-6 gel\r\nfiltration columns and subsequent isoelectric focusing gels. When bag cells are\r\nactivated, a released factor(s) induces egg-laying and comigrates with ELH from\r\ncluster homogenates on P-6 columns. At least three other presumed peptides of\r\nunknown function are also released. These experiments demonstrate that ELH\r\n(6,000 m.w., pl 9.0-9.3) as purified from bag cell cluster homogenates is the major,\r\nactive form secreted from bag cells.
\r\n\r\nIn chapter 2, the effects of ELH on neuronal activity of the attached head\r\nganglia (buccal, cerebral, pleural, and pedal), on the isolated buccal ganglia, as well\r\nas on feeding in intact Aplysia were studied. Starved animals (n = 7) injected at\r\n20\u00b0C with a crude- extract containing ELH stopped eating algae at 17 \u00b1 4 min and\r\ntheir eggs first appeared at 29 \u00b1 4 min after injection. These data clearly indicate\r\nthat a suppression of feeding activity occurs before the appearance of eggs. ELH\r\napplied to the paired buccal ganglia in vitro activates a pair of neurons into a tonic\r\npacing mode (~1 spike/sec). The time for the full appearance of this activity in\r\nvitro correlates well with the time for suppression of feeding in vivo. These\r\nneurons each have an ipsilateral axon in buccal nerve 3. ELH increases the rate of\r\nfiring of a second pair of buccal neurons, each with an ipsilateral axon in the\r\ncerebrobuccal connective. ELH when applied to the attached head ganglia causes\r\nlarge bursts of neuronal activity in pedal nerves to the foot, and increased activity\r\nin the nerve to the penis. These in vitro effects were produced by ELH partially\r\npurified from bag cell cluster homogenates using ammonium sulfate precipitation,\r\nan anion exchange column, and a gel filtration column or by ELH released from\r\nactivated bag cells in isolated abdominal ganglia and then frationated by gel\r\nfiltration. The ELH effects upon the in vitro nervous system support the working ~\r\nhypothesis that ELH in vivo acts directly on the nervous system to suppress feeding\r\nactivity. ELH may also activate neural circuits in the pedal and probably cerebral\r\nganglia that produce characteristic movements of the head during egg-laying; the\r\nrelevant neurons remain to be identified.
\r\n\r\nIn chapter 3, a circadian rhythm (CR) of release of presumed peptides\r\nfrom the isolated eye of Aplysia is demonstrated. This isolated eye is known to\r\nhave a CR of compound action potentials (CAPs) as recorded from its optic nerve.\r\nSubstances labeled with radioactive amino acids and released into the perfusate\r\nwere separated on gel filtration columns and SDS polyacrylamide gels. In the CR\r\nexperiments, the perfusate of a single, labeled, dark-maintained eye was collected\r\nevery 3 h for two days while simultaneously recording the CR of CAPs. Each 3-h\r\nperfusate was applied to a P-2 gel filtration column. Excluded substances\r\n(m.w. ~ 2000) and material fractionated in the region of m.w. ~ 1000 showed a CR\r\nwhich was in phase with the CR of CAPs. Much of these labeled substances can be\r\nprecipitated with trichloroacetic acid. Their release is stimulated by a high\r\npotassium solution and inhibited by a low calcium solution that also inhibits CAP\r\nactivity. This and other previously published evidence suggests that the CAPs and\r\nthe peptide release are directly produced by electrically coupled neurosecretory\r\ncells which may also contain the CR oscillator. One or more of these peptides may\r\nbe a neurohormone and/or transmitter used for synchronizing, entraining and/or\r\ndriving the rest of the animal's CRs.
", "doi": "10.7907/c981-k394", "publication_date": "1978", "thesis_type": "phd", "thesis_year": "1978" }, { "id": "thesis:17849", "collection": "thesis", "collection_id": "17849", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:01302026-191212444", "primary_object_url": { "basename": "Rothman_BS_1976.pdf", "content": "final", "filesize": 91033690, "license": "other", "mime_type": "application/pdf", "url": "/17849/1/Rothman_BS_1976.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Electrophysiological and Biochemical Studies on the Effects of RNA and Protein Synthesis Inhibitors on the Circadian Rhythm of the Isolated Aplysia Eye", "author": [ { "family_name": "Rothman", "given_name": "Barry Samuel", "clpid": "Rothman-Barry-Samuel" } ], "thesis_advisor": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "thesis_committee": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Benzer", "given_name": "Seymour", "clpid": "Benzer-S" }, { "family_name": "Davidson", "given_name": "Eric H.", "clpid": "Davidson-E-H" }, { "family_name": "Mitchell", "given_name": "Herschel K.", "clpid": "Mitchell-H-K" }, { "family_name": "Wiersma", "given_name": "Cornelis A. G.", "clpid": "Wiersma-C-A-G" } ], "local_group": [ { "literal": "div_chem" } ], "abstract": "The isolated eye of Aplysia californica produces a circadian rhythm\r\nof optic nerve activity. In filtered sea water, at 15\u00b0C, in constant\r\ndarkness, the free-running period of the circadian rhythm is 23.4 hrs.\r\nOptic nerve activity is recorded by means of suction electrode, and is\r\nin the form of spontaneous compound action potentials (CAPs) which vary\r\nin frequency from 0 to 200 per hr.
\r\n\r\nExperiments were designed to test the necessity of macromolecular\r\nsynthesis for the production of the circadian rhythm. Eyes were given\r\na pulse of an inhibitor of RNA or protein synthesis and the effects on\r\nthe circadian rhythm, biochemistry or electrophysiology assayed.
\r\n\r\nWhen eyes were given a 3 hr pulse of actinomycin D (AMD)(4 ug/ml\r\nthe circadian rhythm was inhibited without blocking spontaneous\r\nactivity altogether. Eyes receiving a 3 hr pulse of aflatoxin B1(AFTX)\r\n(16 ug/ml) revealed similar effects in half the cases studied, while in\r\nthe other half a reduced amplitude phase delayed circadian rhythm was\r\nfound. Eyes given a 12 hr pulse of puromycin (PURO) (20-134 ug/ml) or\r\ncycloheximide (CHX) (500-2000 ug/ml) beginning in mid-subjective night\r\nhad their circadian rhythms phase delayed by 12-16 hrs and 6-12 hrs,\r\nrespectively, after the drug pulse was washed out. A phase-response\r\ncurve determined for the effects of a 6 hr PURO (125 ug/ml) pulse showed\r\nthat maximum phase delays were caused by pulses given in late subjective\r\nnight, and maximum phase advances caused by pulses given in early subjective\r\nday.
\r\n\r\nIn biochemical studies, incorporation of 3H-uridine and 14C-leucine\r\nwere measured 1-9, 9-17, 49-57 and 73-81 hrs after the removal of a 3 hr\r\npulse of AFTX (16 ug/ml) or AMD (4 ug/ml). Uridine incorporation was\r\ninhibited by 50-75% from 1 to 17 hrs after an AFTX or AMD pulse, while\r\nleucine incorporation was inhibited by 40-70% from 1 to 81 hrs after an\r\nAFTX pulse, and by about 20% from 49 to 57 hrs after an AMD pulse. At\r\nall other times measured, uridine and leucine incorporation were not\r\nsignificantly different from controls. In other biochemical studies the\u00b7\r\neffects of ?URO and CHX on leucine incorporation were tested by means of\r\na double-label 303-polyacrylamide gel system. When eyes were labeled\r\nduring the last 5 hrs of a 12 hr pulse of PUR.O (20 ug/ml) or CHX (500\r\nug/ml), incorporation was inhibited by about 50%. The distribution of\r\nlabel in the gels of PURO-treated eyes showed increasing inhibition of\r\nincorporation with increasing molecular weight above 75,000 daltons,\r\nwhile in the gels of CHX-treated eyes, incorporation was almost equally\r\ninhibited at all molecular weights. A 12 hr PURO (125 ug/ml) inhibited\r\nleucine incorporation by about 85%, while the distribution of label in\r\nthe gels showed increasing inhibition of incorporation with increasing\r\nmolecular weight above 12,000 daltons. At 12-20 hrs and 20-28 hrs after\r\nthe end of the PURO pulse, incorporation was normal except for a small\r\npeak at 20,000 daltons.
\r\n\r\nThe electrophysiological properties of eyes were tested by recording\r\nspontaneous CAP activity and responses to light pulses at various\r\ntimes before, during and after the administration of a drug pulse.\r\nEight electrophysiological parameters were measured and compared quantitatively\r\nbetween experimental and control eyes. They were the latency,\r\namplitude and frequency of both the phasic and tonic light responses;\r\nand the amplitude and frequency of spontaneous CAP activity. AFTX (3\r\nhrs, 16 ug/ml) induced multiphasic tonic light responses during the\r\ndrug pulse; and when applied during the peak of an activity cycle,\r\nincreased the frequency of spontaneous CAP activity by 35% for the\r\nremainder of the cycle. AMD (3 hrs, 4 ug/ml) caused a 13% increase in\r\nspontaneous CAP amplitude and a 10% decrease in tonic light response\r\nlatency subsequent to its removal. PURO (12 hrs, 20 ug/ml) increased\r\nthe amplitude of the tonic light response by 23% when measured more\r\nthan. 7 hrs after the end of the pulse. CHX (12 hrs, 500 ug/ml) caused\r\na 32% increase in the tonic light response frequency measured 0-7 hrs\r\nafter the end of the pulse, and a 33% decrease in the duration of spontaneous\r\nCAP bursts during the pulse.
\r\n\r\nThe results of these experiments indicate that doses of four inhibitors\r\nof macromolecular synthesis capable of modifying the circadian\r\nrhythm of the eye reduce the incorporation of uridine and/or leucine\r\nand cause only small changes in the electrophysiology of the eye.\r\nThese data suggest that the production of the circadian rhythm of the\r\nAplysia eye is dependent on macromolecular synthesis.
", "doi": "10.7907/ay8x-wp67", "publication_date": "1976", "thesis_type": "phd", "thesis_year": "1976" }, { "id": "thesis:10584", "collection": "thesis", "collection_id": "10584", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:12052017-094450464", "type": "thesis", "title": "Part I. Studies on the Organization of the Eye of Aplysia californica. Part II. Studies on the Interrelationship between Two Neuronal Circadian Oscillators in Aplysia californica", "author": [ { "family_name": "Audesirk", "given_name": "Gerald Joseph", "clpid": "Audesirk-Gerald-Joseph" } ], "thesis_advisor": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "thesis_committee": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Wiersma", "given_name": "Cornelis A. G.", "clpid": "Wiersma-C-A-G" }, { "family_name": "Lester", "given_name": "Henry A.", "orcid": "0000-0002-5470-5255", "clpid": "Lester-H-A" }, { "family_name": "Pettigrew", "given_name": "John D.", "clpid": "Pettigrew-J-D" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "Part I
\r\n\r\n\r\nThe isolated eye of Aplysia californica produces a bursting\r\npattern of spontaneous compound action potentials (CAPs) when recordings \r\nare made from the optic nerve in darkness. The CAP frequency varies\r\nwith a circadian rhythm. The light response, also composed of CAPs,\r\nmay be separated into an initial phasic response and a late tonic \r\nresponse similar in form to the dark discharge. Solutions containing\r\nLa+++ or high Mg++ with low Ca++, which are expected to block chemical\r\nsynapses, stop the dark discharge and tonic light response but not the \r\nphasic light response. The suppression of dark discharge by high Mg++\r\nwith low Ca++ is usually temporary, lasting about 0.5 to 4 hours.\r\nSynchrony of the CAPs is not affected by either La+++ or high Mg++, low \r\nCa++. These results indicate that the dark discharge is driven through \r\nchemical synapses, but the light response is not. Replacement of \r\nchloride in the bathing medium by propionate, which uncouples electrical \r\njunctions in the crayfish septate axon, abolishes all CAPs for varying \r\nperiods of time, usually several hours. Propionate leaves the ERG\r\nintact and the optic nerve electrically excitable. A model for inter-neuronal \r\nconnections in the Aplysia eye is constructed from these data. \r\nIt is postulated that the light response is initiated in the photoreceptors, \r\nwith the receptor depolarization passing through electrical \r\nsynapses to higher order cells. Spikes are produced in these cells and \r\npass down their axons in the optic nerve. Spontaneous dark activity\r\nalso represents spiking in these higher order cells, but is initiated\r\nthrough chemical synapses by pacemaker cell(s). Synchrony of the CAPs \r\nis facilitated by electrical synapses between higher order cells. In\r\nlow Ca++ media, these higher order cells may become hyperexcitable to\r\nthe point of autoactivity.
\r\n\r\n\r\n\r\nPart II
\r\n\r\n\r\nThe circadian rhythm of spike output of the single neuron R15 \r\nin the isolated PVG of Aplysia californica can be entrained in vivo \r\nby light. The timing of the rhythm depends not only on the lighting\r\nschedule to which the animal was exposed prior to dissection, but also \r\non the time of dissection relative to that light schedule. Entrainment \r\nof the rhythm by light proceeds very slowly, if at all, in Aplysia \r\nwith their eyes removed. An indirect inhibitory neural pathway is\r\nshown to exist between the eyes and R15, but cutting nervous \r\nconnections containing this and any other neural paths from the eyes \r\nto R15 does not prevent entrainment by light in a majority of animals. \r\nIn vitro experiments show that the eyes can influence the activity \r\nof R15 even when the eyes and the PVG are not neurally connected.\t\r\nThe eyes therefore must release a water soluble factor which can affect\r\nR15, either directly or through some other neurons in the PVG. If the \r\neyes and PVGs from different animals are incubated together for\r\nseveral days and then separated, the subsequent spiking behavior of R15 \r\nis similar to that observed after in vivo entrainment to a light \r\nschedule equivalent in phase to the circadian rhythm of the eyes in \r\nvitro. It is a strong possibility that the factor released by the\r\neyes can entrain the circadian rhythm of R15.
\r\n\r\n \r\n\r\n", "doi": "10.7907/BT9J-NK43", "publication_date": "1975", "thesis_type": "phd", "thesis_year": "1975" }, { "id": "thesis:14432", "collection": "thesis", "collection_id": "14432", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:11202021-011429389", "primary_object_url": { "basename": "RAM_JL_1974.pdf", "content": "final", "filesize": 74580335, "license": "other", "mime_type": "application/pdf", "url": "/14432/1/RAM_JL_1974.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Effects of High K\u207a Media on Leucine Incorporation into Aplysia Nervous Tissue", "author": [ { "family_name": "Ram", "given_name": "Jeffrey Lewis", "clpid": "Ram-Jeffrey-Lewis" } ], "thesis_advisor": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "thesis_committee": [ { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" }, { "family_name": "Attardi", "given_name": "Giuseppe", "clpid": "Attardi-G" }, { "family_name": "Russell", "given_name": "Richard L.", "clpid": "Russell-R-L" }, { "family_name": "Mitchell", "given_name": "Herschel K.", "clpid": "Mitchell-H-K" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "To study possible coupling between membrane polarization and protein synthesis, elevated external K+ levels were used to depolarize the cell membranes in isolated Aplysia californica parieto-visceral ganglia (PVG). The effect of this treatment on the incorporation of labeled leucine into proteins in the ganglion was analyzed on sodium dodecyl sulfate polyacrylamide gels. PVGs were preincubated 3 hours and then incubated 4 hours in either control medium (14C-leucine, 10 mM [ K+]) or experimental medium (3H-leucine, 10 + x mM [K+] with equimolar [Na+] reduction). These were homogenized together, separated into aqueous soluble and aqueous insoluble fractions, and run on gels.
\r\n\r\nIn the aqueous soluble fraction of the PVG High [K+] (90-110 mM [K+]} caused relative increases in incorporation in distinct peaks at 50K (K = 1000 daltons) and 40K. The larger peak, at 50K, was studied further.
\r\n\r\nThe relative increase at 50K occurred when 14c-leucine (instead of the usual 3H-leucine) was incorporated in High [K+]. The relative increase at 50K did not occur (1) when [K+] was raised to only 50 mM; (2) when [Na+] was reduced by 80 mM, and tris+ (HCl to neutralize) was substituted instead of K+; (3) in pleura-visceral connective (PVC) nerve; and (4) in the aqueous insoluble fraction of the PVG.
\r\n\r\nThe effect of High [K+] on incorporation into the giant cell (R2) of the PVG was examined by first labeling the PVG in control medium, rinsing it, and then labeling it in experimental medium. High [K+] in the experimental medium caused a significant relative increase at 50K in whole PVGs, half PVGs, and R2s dissected from the PVG following incubation. The results in R2 were marred by great variability in the control patterns.
\r\n\r\nAutoradiography of identified cells (R2 and R15) dissected from PVGs labeled with 3H-leucine in normal [K+] showed that contaminating cells {mostly glia), which always adhere to such dissected cells, generally account for less than 20% of the total incorporated formalin-fixed label. This contamination is large enough so that a glial origin of the High [K+] effect on incorporation at 50K cannot be positively excluded. However, the presence of this effect in dissected R2s and its absence in PVC nerves, which contain axons, glia, and connective tissue, but no nerve cell bodies, lend support to the notion that the effect is neuronal in origin.
\r\n\r\nHigh [K+] caused a reduction of approximately SO% in total incorporation into both aqueous soluble and aqueous insoluble proteins of the PVG. Similar decreases of 35% were seen in dissected R2s. [Na+] reduction (by 80 mM, tris+ substitution) had no significant effect on total incorporation (measured only in the aqueous soluble fraction of the PVG). High [K+] caused a reduction of approximately 85% in total incorporation into PVC nerve. Autoradiography of the nerve showed that this reduction occurred in both the connective tissue sheath and the axonal-glial region. High [K+] caused no significant change in non-volatile TCA soluble label in either the ganglion or the nerve.
\r\n\r\nOther effects of High [K+] on the PVG: (1) a small (not large enough to have caused the relative increase at 50K) decrease in the relative amount of label in the aqueous soluble, TCA insoluble fraction compared to the aqueous insoluble fraction, and (2) a relative decrease in incorporation in higher molecular weight peptides compared to lower molecular weight peptides in both aqueous soluble and aqueous insoluble fractions.
\r\n\r\nThese results suggest, but do not prove, that High [K+] caused an increase in the synthesis of a neuronal peptide of approximately 50,000 daltons molecular weight. The possibility that this peptide may be a tubulin subunit is briefly discussed.
", "doi": "10.7907/qtf0-tz26", "publication_date": "1974", "thesis_type": "phd", "thesis_year": "1974" }, { "id": "thesis:11184", "collection": "thesis", "collection_id": "11184", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:09172018-103619092", "primary_object_url": { "basename": "Segal_M_1973.pdf", "content": "final", "filesize": 63901754, "license": "other", "mime_type": "application/pdf", "url": "/11184/1/Segal_M_1973.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Hippocampus as a Learning Machine", "author": [ { "family_name": "Segal", "given_name": "Menahem", "clpid": "Segal-Menahem" } ], "thesis_advisor": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" } ], "thesis_committee": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" }, { "family_name": "Bonner", "given_name": "James Frederick", "clpid": "Bonner-J-F" }, { "family_name": "Fender", "given_name": "Derek H.", "clpid": "Fender-D-H" }, { "family_name": "Sperry", "given_name": "Roger Wolcott", "clpid": "Sperry-R-W" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "A series of experiments were conducted with the purposes of\r\ndescribing a functional pathway in the rat hippocampus, characterizing some conditions necessary for activating it, and identifying critical steps in this pathway. In all experiments a classical conditioning paradigm was used and the responses of units in the hippocampus and related forebrain structures to the conditioned stimulus were measured. In the first experiment a few differences between dentate, CA-3, and CA-1, the main fields of the hippocampus, were found. Units in the dentate were first to acquire a conditioned response, CA-3 followed and CA-1 was last. This order fits with the anatomical pathway. However, dentate responses were phasic, that is, did not outlast the CS-US interval, and were not specific to the conditioned stimulus. The responses of CA-3 and CA-1 units, on the other hand, were sustained and specific. The second experiment was devoted to the analysis of conditioned response latencies, in the hippocampus\r\nas well as in septum, subiculum, cingulate, entorhinal, and related structures, all known to be input stages to the hippocampus. In this experiment unconditioned short response latencies were found in the medial septum, one of the afferents of the hippocampus. These were not changed in the process of learning. The shortest conditioned response latencies were found in area CA-3 of the hippocampus. Units in area CA-1 followed, but units in dentate did not precede those of CA-3. Units in entorhinal cortex, the other main afferent to the hippocampus did not seem to precede hippocampal units either. The special relations between the hippocampus and the dentate were demonstrated in another part of this experiment, where dentate units lost their conditioned responses, in the process of extinction, before those of CA-3 and CA-1. It was postulated that septal input triggers CA-3 responses and these\r\nwould be maintained in the presence of reinforcing dentate and\r\nentorhinal inputs.
\r\n\r\nThe relations between the dentate and the hippocampus were\r\nfurther studied in two experiments in which aversive electric shock served as an unconditioned stimulus. In experiment 3 food and shock served as unconditioned stimuli on alternate days. In\r\nexperiment 4 food and shock were presented in the same sessions as unconditioned stimuli to two different CS's. Dentate units had an excitatory conditioned response to a food signal and an inhibitory conditioned response to a shock signal in both experiments. Hippocampal units had excitatory responses to both signals. Acquisition of a conditioned response was not demonstrated within the hippocampus when the conditioned stimulus preceded shock and was slow when food or shock were applied following two different signals in the same session. However, when first trained that a signal precedes food, the conditioned response would be maintained in the hippocampus even if shock is now the US. The dentate is probably involved in the initiation of a conditioned response in the hippocampus but not in the maintenance of it.
\r\n\r\nA sensory-sensory paradigm (experiment 5) has demonstrated\r\nthe presence of unconditioned unhabituated sensory responses in two of the afferents to the hippocampus, that is, the medial septum and the cingulate cortex. It failed to show signs of conditioning in the hippocampus proper. It was proposed that in the absence of an appetitive reward and the activity of the entorhinal-dentate pathway, conditioned responses in hippocampus cannot be established.
\r\n\r\nConditioned entorhinal responses (experiment 6) had long\r\nlatency but also long time constant. Their evoked activity was\r\nmaintained for periods as long as one minute. It was found that\r\nhippocampal responses were larger, if the conditioned stimulus was applied within one minute from the previous trial. Hence, a\r\ncorrelation between hippocampal responses and entorhinal firing\r\nrate was demonstrated. On the basis of these experiments it was\r\nproposed that septal input enters the hippocampus at the CA-3\r\narea, is able to selectively activate these cells only in the\r\npresence of facilitation produced by entorhinal and dentate activity. The facilitatory entorhinal activity is triggered mainly by positive reward.
\r\n", "doi": "10.7907/P1SD-Z263", "publication_date": "1973", "thesis_type": "phd", "thesis_year": "1973" }, { "id": "thesis:10677", "collection": "thesis", "collection_id": "10677", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:02062018-101121529", "type": "thesis", "title": "Unit Activity in the Hypothalamus and Striatum of the Rat During Learning", "author": [ { "family_name": "Linseman", "given_name": "Mary Ann Monica", "clpid": "Linseman-Mary-Ann-Monica" } ], "thesis_advisor": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" } ], "thesis_committee": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" }, { "family_name": "Van Harreveld", "given_name": "Anthonie", "clpid": "Van-Harreveld-A" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Owen", "given_name": "Ray David", "clpid": "Owen-R-D" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "Unit activity was recorded from the hypothalamus and striatum\r\nof 80 freely moving rats during an appetitive classical conditioning \r\nsituation. Responses to auditory stimuli were observed from 118\r\nunits before and during a conditioning procedure in which presentation\r\nof food occurred one second after the onset of an auditory stimulus.\r\nA large proportion of units (111) showed changed responses to the CS \r\nduring conditioning. Only 8 of these, however, showed new conditioned \r\nresponses of the very shortest latency measured, 20 msec. after CS \r\nonset. These were interpreted as likely sites of rerouting of the stimulus \r\ninformation within the brain as a result of learning. They \r\nwere located largely near the intersection of hypothalamic and striatal \r\nstructures. A transient increase in rate of background firing over \r\ntrials was recorded following the onset of conditioning among hypo\u00adthalamic \r\nunits, suggesting they may temporarily represent a dynamic trace of the \r\nnew learning. No significant differences were found between areas \r\nstudied in order of appearance over trials of the conditioned responses. \r\nHowever, as a group, the conditioned responses studied here, appeared \r\nsignificantly earlier than a group of cortical neurons studied under \r\nsimilar conditions. There was greater generalization of response \r\nto the CS- by units of the basal ganglia than other areas, suggesting \r\nthey may be of importance in inhibition of response to the CS-.\r\n\r\n", "doi": "10.7907/9BAS-1713", "publication_date": "1973", "thesis_type": "phd", "thesis_year": "1973" }, { "id": "thesis:11101", "collection": "thesis", "collection_id": "11101", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:07062018-115304742", "primary_object_url": { "basename": "Froehner_SC_1973.pdf", "content": "final", "filesize": 53875734, "license": "other", "mime_type": "application/pdf", "url": "/11101/1/Froehner_SC_1973.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Isolation, Purification and Characterization of Three RNA Polymerases from Novikoff Hepatoma Ascites Tumor", "author": [ { "family_name": "Froehner", "given_name": "Stanley Charles", "clpid": "Froehner-Stanley-Charles" } ], "thesis_advisor": [ { "family_name": "Bonner", "given_name": "James Frederick", "clpid": "Bonner-J-F" } ], "thesis_committee": [ { "family_name": "Bonner", "given_name": "James Frederick", "clpid": "Bonner-J-F" }, { "family_name": "Davidson", "given_name": "Norman R.", "clpid": "Davidson-N-R" }, { "family_name": "Dreyer", "given_name": "William J.", "clpid": "Dreyer-W-J" }, { "family_name": "Mitchell", "given_name": "Herschel K.", "clpid": "Mitchell-H-K" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "DNA-dependent RNA polymerase has been isolated from nuclei of Novikoff hepatoma ascites tumor cells and resolved into three activities, designated Ia, Ib, and II, by a combination of phosphocellulose and DEAE cellulose chromatography. Ia and Ib have been further purified by sucrose density centrifugation. Both gradient profiles exhibit coincidence of the polymerase activity and protein peaks, suggesting that the two may be homogeneous enzymes. Ia migrates as a single species on non-denaturing polyacrylamide gel electrophoresis. SDS polyacrylamide gel electrophoresis indicates that Ia contains subunits of 170,000, 125,000, 69,000, 49,000, 44,000 and 37,000 molecular weights in equimolar ratios except for the\r\n69,000 and 37,000 dalton subunits which may be present in two copies per enzyme molecule. A molecular weight of\r\n600,000 for the enzyme calculated from the molecular weights of the subunits is in good agreement with that determined by exclusion chromatography. The probable molecular structure of Ib is subunits of 190,000 and 135,000 daltons, each present twice per enzyme molecule. The enzymological characterization of these three enzymes suggests that Ia and Ib are the nucleolar polymerases while II is nucleoplasmic. Ia and Ib are most active at low ionic strength with Mg++ on native DNA and are insensitive to \u03b1-amanitin. II prefers Mn++, high ionic strength, a denatured template and is inhibited by low concentrations of \u03b1-amanitin. A factor present in the material which does not bind to the DEAE cellulose column used in the purification scheme, stimulates the activity of all three of the enzymes. Ia and Ib are inactive at low enzyme concentrations in the absence of this factor. The active agent in the factor is probably a protein, since it is heat sensitive, and may be a subunit of the enzyme.
\r\n", "doi": "10.7907/M8Q4-DB66", "publication_date": "1973", "thesis_type": "phd", "thesis_year": "1973" }, { "id": "thesis:9639", "collection": "thesis", "collection_id": "9639", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:04012016-120503899", "primary_object_url": { "basename": "Konopka_rj_1972.pdf", "content": "final", "filesize": 25109976, "license": "other", "mime_type": "application/pdf", "url": "/9639/1/Konopka_rj_1972.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Circadian Clock Mutants of Drosophila melanogaster", "author": [ { "family_name": "Konopka", "given_name": "Ronald Jerome", "clpid": "Konopka-Ronald-Jerome" } ], "thesis_advisor": [ { "family_name": "Benzer", "given_name": "Seymour", "clpid": "Benzer-S" } ], "thesis_committee": [ { "family_name": "Benzer", "given_name": "Seymour", "clpid": "Benzer-S" }, { "family_name": "Lewis", "given_name": "Edward B.", "clpid": "Lewis-E-B" }, { "family_name": "Mitchell", "given_name": "Herschel K.", "clpid": "Mitchell-H-K" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Vinograd", "given_name": "Jerome", "clpid": "Vinograd-J" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "Three mutants of Drosophila melanogaster have been isolated in which the free-running period of the circadian eclosion rhythm and the adult locomotor activity rhythm is affected. One mutant is arrhythmic, another has a short period of 19 hours, and the third has a long period of 28 hours. The mutants retain their phenotypes over the temperature range 18\u00b0 to 25\u00b0 C. All three mutants map near the tip of the X chromosome (distal to the centromere). By deficiency mapping, the short-period mutation has been localized to the 3B1-2 region. Complementation tests show that all three mutations affect the same functional gene.
\r\n\r\nAnalysis of activity rhythms of individual mosaic flies indicates that the site of action of the short-period mutation is probably located in the head of the fly. A few activity patterns of split-head and mixed-head mosaics appear to possess both mutant and heterozygous components, suggesting that the fly head may contain\r\ntwo complete clocks capable of maintaining their periodicities independently.
\r\n\r\nThe short-period mutation affects both the duration of the light-insensitive part of the oscillation and the degree to which the clock can be reset during the light-sensitive part of the oscillation.
\r\n\r\nBoth the short-period and long-period mutant eclosion rhythms can be entrained to a period of 24 hours by a 12:12 light-dark cycle having a light intensity at least two orders of magnitude greater than that required to entrain the normal rhythm. The arrhythmic mutant does not entrain under these conditions. In the presence of a temperature cycle, however, the arrhythmic mutant does entrain, but its rhythm damps out when the temperature cycle is removed.
\r\n\r\nEvidence is presented that Pittendrigh's two-oscillator model for the clock in D. pseudoobscura applies to D. melanogaster as well. The three clock mutations primarily affect the light- sensitive driving oscillator. The arrhythmic mutation appears to have eliminated the driving oscillator while leaving the temperature-sensitive driven oscillator relatively intact.
\r\n", "doi": "10.7907/R04B-3425", "publication_date": "1972", "thesis_type": "phd", "thesis_year": "1972" }, { "id": "thesis:9694", "collection": "thesis", "collection_id": "9694", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05022016-093643296", "primary_object_url": { "basename": "Kornblith_cl_1972.pdf", "content": "final", "filesize": 21562260, "license": "other", "mime_type": "application/pdf", "url": "/9694/1/Kornblith_cl_1972.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Conditioned Responses in the Reticular Formation", "author": [ { "family_name": "Kornblith", "given_name": "Carol Lee", "clpid": "Kornblith-Carol-Lee" } ], "thesis_advisor": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" } ], "thesis_committee": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" }, { "family_name": "Owen", "given_name": "Ray David", "clpid": "Owen-R-D" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Van Harreveld", "given_name": "Anthonie", "clpid": "Van-Harreveld-A" }, { "family_name": "Wiersma", "given_name": "Cornelis A. G.", "clpid": "Wiersma-C-A-G" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "Unit activity was recorded from the midbrain and pons of 40 freely moving rats in an appetitive classical conditioning situation. Responses to auditory stimuli were observed from 100 units before and during a conditioning procedure in which presentation of food occurred 1 sec after the onset of the auditory stimulus. Conditioned unit responses (i.e., spike rate accelerations or decelerations) were considered to be positive when 1) no similar responses appeared prior to conditioning, and 2) latencies were equal to or less than those of sensory responses derived from the inferior colliculus. Such short latency conditioned unit responses were recorded from 11 probes located in the mid-lateral pert of the ventral region of the brain stem. This region was differentiated from paramedian, far lateral and dorsal parts of the brain stem reticular formation. Conditioned unit responses of considerably longer latencies were recorded from 76 probe located in these other regions. Among the longer latency responses interesting differences appeared in experiments conducted after the first conditioning series was completed. With additional training, units in the \"reticular activating system\" of midbrain and pons tended to yield stabilized responses in the early portion of the\r\nCS-US interval closely related in time to the orientation responses evoked by the CS. In contrast, the responses of units in the limbic midbrain tended to stabilize in the later part of the CS-US interval closely related in time to preparatory responses tied to the US. During extinction when the auditory stimulus was no longer followed by presentation of food, many of the responses were reduced to their pre-conditioning levels. However, there was a tendency for units which had displayed short latency responses on the first conditioning day to be more resistant to extinction than units which had displayed longer latency conditioned responses. The data were interpreted as indicating a local correlate of learning in the reticular formation of midbrain end pons and a separation of the midbrain system into at least two areas: 1) the classical \"reticular activating system\" related to orienting reactions, and 2) the limbic midbrain areas related to drives and rewards. Because the ventral and mid-lateral area with very short latency conditioned responses was not clearly tied to either of these; it was considered as possibly representing a third division.", "doi": "10.7907/J6N6-EV96", "publication_date": "1972", "thesis_type": "phd", "thesis_year": "1972" }, { "id": "thesis:9908", "collection": "thesis", "collection_id": "9908", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:08302016-104724672", "primary_object_url": { "basename": "Ahmed_na_1968.pdf", "content": "final", "filesize": 28041014, "license": "other", "mime_type": "application/pdf", "url": "/9908/1/Ahmed_na_1968.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Iodide Space in Rabbit Brain", "author": [ { "family_name": "Ahmed", "given_name": "Nawal Abd El-Hay", "clpid": "Ahmed-Nawal-Abd-El-Hay" } ], "thesis_advisor": [ { "family_name": "Van Harreveld", "given_name": "Anthonie", "clpid": "Van-Harreveld-A" } ], "thesis_committee": [ { "family_name": "Van Harreveld", "given_name": "Anthonie", "clpid": "Van-Harreveld-A" }, { "family_name": "Benzer", "given_name": "Seymour", "clpid": "Benzer-S" }, { "family_name": "Dreyer", "given_name": "William J.", "clpid": "Dreyer-W-J" }, { "family_name": "Roberts", "given_name": "John D.", "clpid": "Roberts-J-D" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "In the present investigation labeled iodide was used to investigate the interrelationship between brain, blood and cerebrospinal fluid, to examine active transport across the blood-brain- and the blood-cerebrospinal fluid barriers, and to estimate the extracellular space of the brain.
\r\n\r\nThe iodide space in the brain and the iodide concentration in cerebrospinal fluid after intravenous administration of radioactive iodide are determined by the following mechanisms. Iodide passes into the cerebrospinal fluid but active transport in the choroid plexus moves most of the iodide back again into the plasma, keeping the concentration at a very law value. An extracellular fluid is formed at the blood-brain barrier possibly in a similar way. The iodide concentration of this fluid is unknown but is probably higher than that in the cerebrospinal fluid. Diffusion of iodide across the brain-cerebrospinal fluid barrier transports this ion from the brain into the cerebrospinal fluid which is constantly renewed \"sink action\".
\r\n\r\nThe iodide space was found to be 2.4% four to five hours after the intravenous administration of 131I, the iodide content of the cerebrospinal fluid was 1.2% of that of the TCA serum filtrate. The iodide space increased to 10.6% in preparations in which in addition to 131I unlabeled iodide (to a serum concentration of 25 to 50 mM) was administered to saturate the active transport processes in the choroid plexuses and blood-brain barrier. The iodide activity of the cerebrospinal fluid in these experiments increased to 29.3% of that in the TCA serum filtrate. In experiments in which the inhibitor of iodide transport, perchlorate (8 mM), was injected intravenously with the 131I-, the iodide space was 8.2% and the iodide concentration in the cerebrospinal fluid 26.4%. These experiments demonstrate the effect of saturation and inhibition of active transport on the iodide space. They show furthermore that the depression of the active transport did not raise the iodide concentration in the cerebrospinal fluid to the plasma concentration. The relatively low (1/3 of that in the serum TCA filtrate) iodide concentration in the cerebrospinal fluid under these circumstances was ascribed to a differential permeability of the blood-cerebrospinal fluid barrier for iodide and chloride.
\r\n\r\nThe sink action can be eliminated by perfusion of the ventricles with an artificial cerebrospinal fluid containing iodide. Ventriculocisternal perfusion with 131I- alone resulted in an iodide space of 7.2% after 4.5 hours. An iodide space of 10.2% was determined by a combined intravenous administration and ventricular perfusion with an artificial cerebrospinal fluid containing the same concentration of 131I as present in the plasma. When in similar experiments perchlorate was administered intravenously, the iodide space rose to 16.8%. The iodide space determined by simultaneous intravenous injection and ventricular perfusion with both labeled and unlabeled iodide, in a concentration sufficient to saturate the active transport, was 20.8%. In the latter instances the sink action is eliminated and also active transport is inhibited or saturated. It was postulated that under these conditions the iodide concentration in plasma and brain extracellular fluid are approximately the same. The use of the iodide space as a measure of the brain extracellular space was discussed.
", "doi": "10.7907/E49K-K156", "publication_date": "1968", "thesis_type": "phd", "thesis_year": "1968" } ]