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Nancy L. Wayne - One of the best experts on this subject based on the ideXlab platform.
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Synaptic stimulation of Aplysia peptidergic neurons can activate Hormone secretion in the absence of an afterdischarge.
Neuroscience letters, 2004Co-Authors: Nancy L. Wayne, Stephan MichelAbstract:For over 20 years, the bag cell neurons of the marine mollusk Aplysia have been used to investigate second-messenger pathways that mediate effects of synaptic stimulation on ion currents and membrane excitability, presumably leading to exocytotic release of the neuropeptide Egg-Laying Hormone (ELH). It is widely cited that a train of action potentials, called an afterdischarge, is necessary for activating cellular events leading to ELH secretion. Using a combination of electrophysiology, optical imaging of calcium signaling, and radioimmunoassay of ELH secretion, we show that an afterdischarge is not required for ELH secretion. Electrical stimulation that failed to produce afterdischarges but did lead to prolonged membrane depolarization and a rise in intracellular calcium concentration was sufficient to stimulate significant ELH release.
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Secretion of locally synthesized neuroHormone from neurites of peptidergic neurons.
Journal of neurochemistry, 2003Co-Authors: Wenjau Lee, Nancy L. WayneAbstract:Local protein synthesis in neuronal processes is a common phenomenon and may play an important role in synaptic plasticity and hormonal regulation. We have used neuroendocrine bag cells of Aplysia californica as a model system to study local protein synthesis. In our previous work we found that bag cell neurites are capable of synthesizing and processing the proHormone of Egg-Laying Hormone (pro-ELH). In the present study, we found that bag cell neurites are also capable of releasing locally synthesized pro-ELH and ELH-related products via both constitutive and regulated pathways. However, an electrical afterdischarge did not enhance local pro-ELH synthesis, as it does in the bag cell soma. This is the first evidence that isolated neurites are capable of secreting locally synthesized proteins.
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Post-afterdischarge depolarization does not stimulate prolonged neuroHormone secretion but is required for activity-dependent stimulation of neuroHormone biosynthesis from peptidergic neurons.
Endocrinology, 2003Co-Authors: Nancy L. Wayne, Wenjau Lee, Stephan Michel, Sarah Buxton De QuintanaAbstract:Membrane depolarization plays a critical role in stimulating secretion of neuropeptides and can also be important in regulating transcriptional and translational events that control peptide biosynthesis. The purpose of this study was to test the hypothesis that persistent membrane depolarization after the end of an electrical afterdischarge plays an important role in stimulating both prolonged secretion of Egg-Laying Hormone (ELH) and ELH synthesis from peptidergic bag cell neurons of Aplysia. Experimental preparations were treated with a low Na+ solution to rapidly repolarize membrane potential (Vm). Compared with control preparations, the low Na+ solution caused rapid membrane repolarization to resting levels, significant shortening of the duration of the afterdischarge, and significant decrease in the decay time constant of cytosolic Ca2+ ([Ca2+]i) concentrations, but no effect on peak [Ca2+]i, total [Ca2+]i above baseline, or duration of elevated [Ca2+]i. Contrary to both theoretical expectations and ...
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An activity-dependent switch to cap-independent translation triggered by eIF4E dephosphorylation
Nature Neuroscience, 2003Co-Authors: John R. Dyer, Wenjau Lee, Nancy L. Wayne, Stephan Michel, Vincent F. Castellucci, Wayne S. SossinAbstract:The rate of translation of Egg-Laying Hormone (ELH) in Aplysia californica bag cell neurons rises after an afterdischarge (AD), the physiological trigger for Egg-Laying^ 1 . We found that the 5′ untranslated region (5′ UTR) of ELH possessed an internal ribosomal entry site (IRES), and that an AD was accompanied by a switch to cap-independent, IRES-mediated translation, indicating that the use of a cellular IRES can be regulated by physiological activity. Furthermore, the AD caused dephosphorylation of the initiation factor eIF4E, which was sufficient to increase use of the ELH IRES, showing that dephosphorylation of eIF4E can trigger a switch to IRES-mediated translation.
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Regional differences in processing of locally translated proHormone in peptidergic neurons of Aplysia californica.
Journal of neurochemistry, 2002Co-Authors: Wenjau Lee, Andrea M. Jones, Joyce K. Ono, Nancy L. WayneAbstract:Earlier work showed that cell bodies and neurites of the peptidergic bag cell neurons of Aplysia californica contain mRNA for Egg-Laying Hormone. The purpose of the present study was to determine if Egg-Laying Hormone synthesis and proHormone processing is similar in the pleurovisceral connective nerves (containing neurites of bag cell neurons) and the bag cell neuron clusters (containing both cell bodies and neurites of bag cell neurons). Initial experiments confirmed by RT-PCR and sequencing that Egg-Laying Hormone mRNA was present in the pleurovisceral connective nerves. To investigate possible regional differences in translation of mRNA and proHormone processing, clusters were separated from connective nerves and newly synthesized Egg-Laying Hormone-immunoreactive proteins were analyzed. Results showed that synthesis and processing of proHormone occurred in both the clusters and isolated connective nerves; however, the relative abundance of proHormone, processing intermediates, and Egg-Laying Hormone was different. Pulse-chase experiments showed that proHormone was processed more slowly in the connective nerves than in the clusters. These results show that mRNA in isolated neural processes of neuroendocrine cells can be translated, and that the cellular machinery for protein synthesis is present, but processing of the ELH proHormone is significantly compromised.
Mariana F. Wolfner - One of the best experts on this subject based on the ideXlab platform.
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evidence for structural constraint on ovulin a rapidly evolving drosophila melanogaster seminal protein
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Alex Wong, Shannon N Albright, Mariana F. WolfnerAbstract:The Egg-Laying Hormone ovulin (Acp26Aa) is among the most rapidly evolving proteins in the Drosophila genome. Against the background of ovulin's high sequence variability within and between species, we have identified highly conserved motifs that may play an important structural role. Using yeast two-hybrid and GST-pull-down assays, we show that ovulin interacts with itself. The C terminus of ovulin is necessary and sufficient for self-interaction, with its C-terminal 45 aa pLaying a major role. Under nonreducing conditions, ovulin participates in a high-molecular-mass complex, suggesting that it occurs in an oligomeric form. One or more of three predicted coiled-coil domains in the C terminus of ovulin may be involved in its self-interaction. These structural elements are conserved between species despite an overall rapid pace of evolution in ovulin's primary sequence. We therefore suggest that domains involved in ovulin's self-interaction form a conserved structural backbone for the protein, resulting in greater evolutionary flexibility at other sites.
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A Drosophila seminal fluid protein, Acp26Aa, stimulates Egg Laying in females for 1 day after mating
Proceedings of the National Academy of Sciences of the United States of America, 1995Co-Authors: Laura A. Herndon, Mariana F. WolfnerAbstract:Abstract Mating triggers behavioral and physiological changes in the Drosophila melanogaster female, including an elevation of Egg Laying. Seminal fluid molecules from the male accessory gland are responsible for initial behavioral changes, but persistence of these changes requires stored sperm. Using genetic analysis, we have identified a seminal fluid protein that is responsible for an initial elevation of Egg Laying. This molecule, Acp26Aa, has structural features of a proHormone and contains a region with amino acid similarity to the Egg-Laying Hormone of Aplysia. Acp26Aa is transferred to the female during mating, where it undergoes processing. Here we report the generation and analysis of mutants, including a null, in Acp26Aa. Females mated to male flies that lack Acp26Aa lay fewer Eggs than do mates of normal males. This effect is apparent only on the first day after mating. The null mutation has no other detectable physiological or behavioral effects on the male or the mated female.
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Male and female cooperate in the proHormone-like processing of a Drosophila melanogaster seminal fluid protein.
Developmental biology, 1995Co-Authors: Morgan Park, Mariana F. WolfnerAbstract:Acp26Aa is a Drosophila seminal fluid protein that plays a role in the elevation of Egg-Laying by the mated female and has structural features of a proHormone. The protein, which has a region of sequence similarity to the Egg-Laying Hormone of Aplysia, is transferred to the Drosophila female during mating. Acp26Aa is processed in the mated female's genital tract. We show here that the processing involves sequential proteolytic cleavages, and we map the position of these cleavages. Although Acp26Aa is not cleaved in the male, its processing in the mated female requires activities donated by the male. Acp26Aa ectopically expressed in unmated females is not processed. Processing of Acp26Aa in wild-type females mated to males with altered seminal fluid is dependent on the presence and amount of male accessory gland secretions. The need for molecular cooperation between the sexes for processing of Acp26Aa could restrict its activity to the mated female.
Prasert Sobhon - One of the best experts on this subject based on the ideXlab platform.
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Existence of an Egg-Laying Hormone-like peptide in male reproductive system of the giant freshwater prawn, Macrobrachium rosenbergii.
Acta histochemica, 2018Co-Authors: Thanapong Kruangkum, Scott F Cummins, Chaitip Wanichanon, Jirawat Saetan, Charoonroj Chotwiwatthanakun, Rapeepun Vanichviriyakit, Prasert SobhonAbstract:The giant freshwater prawn, Macrobrachium rosenbergii, is an important aquaculture species. A better understanding of the molecular components of reproduction in this species would help to advance the prawn production. In the present study, we demonstrated the presence of an Egg Laying Hormone (ELH)-like peptide in the male reproductive system. First, an antibody to the abalone (a)ELH was generated, and by Western blot it was shown to specifically bound to a protein from the male M. rosenbergii reproductive tissues with a similar size to molluscan ELH. This aELH-like peptide was localized in spermatogonia in the testes of all three male morphotypes: blue claw, orange claw and small males. Moreover, the aELH-like peptide was detected in the epithelium of the spermatic duct and its associated smooth muscle cell layers and on the outer surface of spermatozoa. As well, the aELH-like peptide was detected in the spermatophore located in the female thelycum at 4-6 h post-mating, indicating that it was transferred to the female during copulation. Taken together, we suggest that this aELH-like peptide could be as a male inducing factor that helped to accelerate female spawning. Liquid chromatography of crude extracts and immunoblot analysis suggested that the aELH-like peptide could be further purified for ultimate characterization.
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Distribution of abalone Egg-Laying Hormone-like peptide in the central nervous system and reproductive tract of the male mud crab, Scylla olivacea
Acta histochemica, 2018Co-Authors: Kanjana Khornchatri, Thanapong Kruangkum, Jirawat Saetan, Tipsuda Thongbuakaew, Thanyaporn Senarai, Napamanee Kornthong, Yotsawan Tinikul, Prasert SobhonAbstract:The mud crab, Scylla olivacea, is a high value economic marine animal in Thailand. However, collection of these crabs from natural habitat for local consumption and export has caused rapid population decline. Hence, aquaculture of this species is required and to this measure understanding of endocrine control of their reproduction must be understood. Egg Laying Hormone (ELH) is a neuropeptide synthesized by the bag cells (neurons) in the abdominal ganglia of Aplysia gastropods. It plays a critical role in controlling Egg production and Laying in gastropods, and its possible homolog (ELH-like peptide) was reported in the neural and ovarian tissues of prawns and recently in female reproductive tract of the blue swimming crab, Portunus pelagicus. In this study, we have studied the histology of the male reproductive tract in Scylla olivacea which are comprised of anterior testis, posterior testis, early proximal spermatic duct (ePSD), proximal spermatic duct (PSD), middle spermatic duct (MSD) and distal spermatic duct (DSD), by immunohistochemistry, detected an abalone ELH- immunoreactivity (aELH-ir) in epithelium of ducts in posterior testis and epithelium of all parts of spermatic duct. Furthermore, we could detect aELH-ir in neurons of cluster 9, 11, olfactory neuropil (ON) in the brain and in the small neurons located between the third and the fourth thoracic neuropils (T3-T4) and between the fourth and the fifth thoracic neuropils (T4-T5) of thoracic ganglia. Thus, the presence of aELH in male S. olivacea was designated the role of female Egg Laying behavior in the male mud crab.
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the presence of abalone Egg Laying Hormone like peptide in the central nervous system and ovary of the blue swimming crab portunus pelagicus and its effect on ovarian maturation
Aquaculture, 2017Co-Authors: Jirawat Saetan, Prasert Sobhon, Thanapong Kruangkum, Kanjana Khornchatri, Tipsuda Thongbuakaew, Thanyaporn Senarai, Piyachat Chansela, Montakan TamtinAbstract:Abstract Egg-Laying Hormone (ELH) is a neuropeptide secreted from the neural ganglia of mollusks that can stimulate the Egg-Laying and associated behaviors. In the present study, using a polyclonal antibody against an abalone, H asinina , ELH (aELH) we could detect the aELH-like immunoreactivity (aELH-l-ir) in the central nervous system (CNS) and ovary of the blue swimming crab Portunus pelagicus . In protocerebrum, aELH-l-ir was detected in the small- and medium- sized neurons of cluster 6, anterior/posterior medial protocerebral neuropils, protocerebral bridge and central body. In deutocerebrum, the aELH-l-ir was observed in small-sized neurons of cluster 9, fibers between small-sized neurons of cluster 10, medium-sized neurons of cluster 11, olfactory neuropil and medial/lateral antenna I neuropils. In tritocerebrum, the medium- sized neurons of cluster 16, the tritocerebral commissure, and tegumental neuropil showed strong aELH-l-ir. In the ventral nerve cord, the aELH-l-ir was detected in the small- and medium-sized neurons of dorsolateral clusters of subesophageal ganglion. There was no aELH-l- ir in neurons of thoracic ganglion, but aELH-l-ir exhibited a dot-like structure in the subcapsular space around the thoracic neuropils. In abdominal ganglion, the aELH-l-ir was detected in some medium-sized neurons and abdominal neuropils. In the ovary, the aELH-l-ir was detected in the cytoplasm of oogonia, and all steps of developing oocytes. The effect of aELH on ovarian maturation in the crabs was examined by bioassay. When mature female crabs were injected with a dose of 500 ng/g body weight per crab, the ovarian maturation was accelerated as indicated by the rising of gonado-somatic index and levels of vitellin in the ovarian tissue and hemolymph, which was confirmed by histological studies. The aELH also enhanced the proliferation of follicular cells as indicated by the increased number of BrdU-labeled nuclei. In addition, the aELH also significantly induced the 17β-estradiol and progesterone secretion in the cultured ovarian explant. In conclusion, this study demonstrated the existence of an aELH-liked-peptide in the CNS and ovary of the P . pelagicus , and it can induce the ovarian 17β-estradiol and progesterone production resulting in early ovarian maturation in this crab.
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The presence of abalone Egg-Laying Hormone-like peptide in the central nervous system and ovary of the Spotted Babylon, Babylonia areolata.
Acta histochemica, 2017Co-Authors: Jirawat Saetan, Prasert Sobhon, Thanapong Kruangkum, Piyakorn Boonyoung, Uraporn Vongvatcharanon, Kanjana Khornchatri, Pinij Thaweethamsewee, Prapee SretarugsaAbstract:Recently, the neuronal classification of the ivory shell Spotted Babylon, Babylonia areolata, was readily demonstrated. Regarding its importance as marine economic molluscan species, the attempt to understand the neuroendocrine regulation is necessary. This study firstly demonstrated the neurosecretory cells as well as the existence and distribution of the Egg-Laying Hormone (ELH)-like peptide in the central nervous system (CNS) and ovary of the B. areolata. The neurosecretory cell was characterized by the cytoplasmic purple dot-like structure as stained by the Gomori's paraldehyde fuchsin. Using the anti-abalone (a) ELH, we detected the aELH-like-peptide in neurons (Nr) and neurosecretory cells (Ns) of all ganglia including the cerebral, pleural, parietal, pedal and buccal ganglia. The aELH-like peptide was also present in the neuropil of each. It was noted that not all Ns presented the aELH-like peptide. In the ovary, the aELH-like peptide was slightly detected in early developing oocytes and strongly detected in late developing oocytes and follicular cells. This study firstly reported the evidence of ELH-like peptide in the CNS and ovary of the B. areolata. The molecular cloning as well as to investigate the function of ELH in this species is needed as it will be beneficial for future applications in aquaculture.
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Stimulatory Effects of Egg-Laying Hormone and Gonadotropin-Releasing Hormone on Reproduction of the Tropical Abalone, Haliotis asinina Linnaeus
Journal of Shellfish Research, 2010Co-Authors: Parinyaporn Nuurai, Peter J. Hanna, Prasert Sobhon, Attakorn Engsusophon, Tanes Poomtong, Prapee Sretarugsa, Chaitip WanichanonAbstract:ABSTRACT Egg-Laying Hormone (ELH) is a neuropeptide Hormone that stimulates ovulation of gastropods, including Aplysia californica and Lymnaea stagnalis. Other neuropeptides, gonadotropin releasing Hormones (GnRHs), also play important roles in controlling reproduction in both vertebrates and invertebrates. In the current study, the effects of abalone ELH (aELH) and several GnRHs on somatic growth, sex differentiation, gonad maturation, and spawning of Haliotis asinina were investigated in 3 experiments. In experiment 1, groups of 4-mo-old juveniles (11.8 ± 0.03 mm shell length (SL) and 0.33 ± 0.04 g body weight (BW)) were injected with aELH and GnRHs, including buserelin (mammalian GnRH analogue), octopus GnRH (octGnRH), and tunicate GnRH-I (tGnRH-I), at doses of 20 ng/g BW and 200 ng/g BW. The aELH induced early sex differentiation with a bias toward females, but with normal somatic growth, whereas the different isoforms of GnRH had no effect on sexual differentiation or somatic growth. In experiment 2,...
Wenjau Lee - One of the best experts on this subject based on the ideXlab platform.
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Secretion of locally synthesized neuroHormone from neurites of peptidergic neurons.
Journal of neurochemistry, 2003Co-Authors: Wenjau Lee, Nancy L. WayneAbstract:Local protein synthesis in neuronal processes is a common phenomenon and may play an important role in synaptic plasticity and hormonal regulation. We have used neuroendocrine bag cells of Aplysia californica as a model system to study local protein synthesis. In our previous work we found that bag cell neurites are capable of synthesizing and processing the proHormone of Egg-Laying Hormone (pro-ELH). In the present study, we found that bag cell neurites are also capable of releasing locally synthesized pro-ELH and ELH-related products via both constitutive and regulated pathways. However, an electrical afterdischarge did not enhance local pro-ELH synthesis, as it does in the bag cell soma. This is the first evidence that isolated neurites are capable of secreting locally synthesized proteins.
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Post-afterdischarge depolarization does not stimulate prolonged neuroHormone secretion but is required for activity-dependent stimulation of neuroHormone biosynthesis from peptidergic neurons.
Endocrinology, 2003Co-Authors: Nancy L. Wayne, Wenjau Lee, Stephan Michel, Sarah Buxton De QuintanaAbstract:Membrane depolarization plays a critical role in stimulating secretion of neuropeptides and can also be important in regulating transcriptional and translational events that control peptide biosynthesis. The purpose of this study was to test the hypothesis that persistent membrane depolarization after the end of an electrical afterdischarge plays an important role in stimulating both prolonged secretion of Egg-Laying Hormone (ELH) and ELH synthesis from peptidergic bag cell neurons of Aplysia. Experimental preparations were treated with a low Na+ solution to rapidly repolarize membrane potential (Vm). Compared with control preparations, the low Na+ solution caused rapid membrane repolarization to resting levels, significant shortening of the duration of the afterdischarge, and significant decrease in the decay time constant of cytosolic Ca2+ ([Ca2+]i) concentrations, but no effect on peak [Ca2+]i, total [Ca2+]i above baseline, or duration of elevated [Ca2+]i. Contrary to both theoretical expectations and ...
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An activity-dependent switch to cap-independent translation triggered by eIF4E dephosphorylation
Nature Neuroscience, 2003Co-Authors: John R. Dyer, Wenjau Lee, Nancy L. Wayne, Stephan Michel, Vincent F. Castellucci, Wayne S. SossinAbstract:The rate of translation of Egg-Laying Hormone (ELH) in Aplysia californica bag cell neurons rises after an afterdischarge (AD), the physiological trigger for Egg-Laying^ 1 . We found that the 5′ untranslated region (5′ UTR) of ELH possessed an internal ribosomal entry site (IRES), and that an AD was accompanied by a switch to cap-independent, IRES-mediated translation, indicating that the use of a cellular IRES can be regulated by physiological activity. Furthermore, the AD caused dephosphorylation of the initiation factor eIF4E, which was sufficient to increase use of the ELH IRES, showing that dephosphorylation of eIF4E can trigger a switch to IRES-mediated translation.
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Regional differences in processing of locally translated proHormone in peptidergic neurons of Aplysia californica.
Journal of neurochemistry, 2002Co-Authors: Wenjau Lee, Andrea M. Jones, Joyce K. Ono, Nancy L. WayneAbstract:Earlier work showed that cell bodies and neurites of the peptidergic bag cell neurons of Aplysia californica contain mRNA for Egg-Laying Hormone. The purpose of the present study was to determine if Egg-Laying Hormone synthesis and proHormone processing is similar in the pleurovisceral connective nerves (containing neurites of bag cell neurons) and the bag cell neuron clusters (containing both cell bodies and neurites of bag cell neurons). Initial experiments confirmed by RT-PCR and sequencing that Egg-Laying Hormone mRNA was present in the pleurovisceral connective nerves. To investigate possible regional differences in translation of mRNA and proHormone processing, clusters were separated from connective nerves and newly synthesized Egg-Laying Hormone-immunoreactive proteins were analyzed. Results showed that synthesis and processing of proHormone occurred in both the clusters and isolated connective nerves; however, the relative abundance of proHormone, processing intermediates, and Egg-Laying Hormone was different. Pulse-chase experiments showed that proHormone was processed more slowly in the connective nerves than in the clusters. These results show that mRNA in isolated neural processes of neuroendocrine cells can be translated, and that the cellular machinery for protein synthesis is present, but processing of the ELH proHormone is significantly compromised.
Jonathan V. Sweedler - One of the best experts on this subject based on the ideXlab platform.
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Measuring the peptides in individual organelles with mass spectrometry
Nature biotechnology, 2000Co-Authors: Stanislav S. Rubakhin, Rebecca W. Garden, Robert R. Fuller, Jonathan V. SweedlerAbstract:New sampling protocols combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allow the assay of single dense core vesicles. Understanding the packaging of vesicles is important as vesicles are the quanta of information for intercellular communication. Using vesicles from the exocrine atrial gland of Aplysia californica as the model, a wide range of bioactive peptides are detected within each vesicle. Although the expression of the Egg-Laying Hormone gene family of type 1 atrial gland cells has been previously examined, chemical characterization of individual 1-2 microm diameter vesicles demonstrates that products from several genes are colocalized. The mass sensitivity of MALDI MS can be further improved to enable the analysis of even smaller subcellular organelles.
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Proteolytic processing of the Aplysia Egg-Laying Hormone proHormone
Proceedings of the National Academy of Sciences of the United States of America, 1998Co-Authors: Rebecca W. Garden, Scott A. Shippy, Tatiana P. Moroz, Jonathan V. SweedlerAbstract:By using matrix-assisted laser desorption/ionization time-of-flight MS, individual peptidergic neurons from Aplysia are assayed. A semiquantitative method is developed for comparing single-cell profiles by using spectral normalization, and peptides are localized to specific cells by mass spectrometric cell mapping. In addition to all previously identified products of the Egg-Laying Hormone (ELH) gene, other peptides are formed from proteolytic hydrolysis of Leu-Leu residues within ELH and acidic peptide (AP). AP exhibits further processing to yield AP1–20 and AP9–27. These peptides appear to be colocalized in vesicles with ELH, transported to specific neuronal targets, and released in a Ca2+-dependent manner. A differential peptide distribution is observed at a specific target cell, and a low-frequency variation of AP, [Thr21]AP, is detected in a single animal.
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Mass spectrometric survey of interganglionically transported peptides in Aplysia
Peptides, 1998Co-Authors: Tatiana P. Moroz, Rebecca W. Garden, Klaudiusz R. Weiss, Philip D. Floyd, Jonathan V. SweedlerAbstract:Abstract The major ganglionic connectives in Aplysia are assayed to determine putative neuropeptides. Matrix-assisted laser desorption/ionization mass spectrometry allows direct measurement of peptides in a nerve. Many previously characterized peptides are observed, including APGWamide, buccalins, small cardioactive peptides, and Egg-Laying Hormone. Several unreported peptides are detected in specific nerves, suggesting they may have important physiological roles. Furthermore, novel processing products of the L5–67 precursor peptide and the APGWamide/cerebral peptide 1 proHormone are strongly suggested, and their interganglionic transport demonstrated.