RNA-binding protein BrunoL1 mediates translational stimulation of specific mRNAs including cenp-a... more RNA-binding protein BrunoL1 mediates translational stimulation of specific mRNAs including cenp-a and cyclinA2 via interactions with eIF3:
Cephalopod mollusks are renowned for their colorful and dynamic body patterns, produced by an ass... more Cephalopod mollusks are renowned for their colorful and dynamic body patterns, produced by an assemblage of skin components that interact with light. These may include iridophores, leucophores, chromatophores and (in some species) photophores. Here, we present molecular evidence suggesting that cephalopod chromatophores - small dermal pigmentary organs that reflect various colors of light - are photosensitive. RT-PCR revealed the presence of transcripts encoding rhodopsin and retinochrome within the retinas and skin of the squid Doryteuthis pealeii, and the cuttlefish Sepia officinalis and Sepia latimanus. In D. pealeii, Gqα and squid TRP channel transcripts were present in the retina and in all dermal samples. Rhodopsin, retinochrome and Gqα transcripts were also found in RNA extracts from dissociated chromatophores isolated from D. pealeii dermal tissues. Immunohistochemical staining labeled rhodopsin, retinochrome and Gqα proteins in several chromatophore components, including pi...
In Lymnaea stagnalis, in order to obtain a 10 min short-term memory (STM) of taste avoidance cond... more In Lymnaea stagnalis, in order to obtain a 10 min short-term memory (STM) of taste avoidance conditioning (TAC) at least 10 paired presentations of a conditioned stimulus (CS), sucrose, and an unconditioned stimulus (US), tactile stimulation to the animal's head, are required. Pre-exposure of snails to the protein kinase C (PKC) α and ε activator bryostatin (Bryo) facilitated STM formation in that only 5 paired CS-US trials were required. Typically 20 paired presentations of the CS-US are required for formation of STM and LTM. However, 20 paired presentations do not result in STM or LTM if snails are pre-incubated with a PKC inhibitor, Ro-32-0432. We also found that LTM lasting longer than 48 h was acquired with Bryo incubation for 45 min even after termination of the conditioning paradigm. These data suggest that activation of the α and ε isozymes of PKC is crucially involved in the formation of LTM and provide further support for a mechanism that has been conserved across the evolution of species ranging from invertebrate molluscs to higher mammals.
Cuttlefish, Sepia officinalis , possess neurally controlled, pigmented chromatophore organs that ... more Cuttlefish, Sepia officinalis , possess neurally controlled, pigmented chromatophore organs that allow rapid changes in skin patterning and coloration in response to visual cues. This process of adaptive coloration is enabled by the 500% change in chromatophore surface area during actuation. We report two adaptations that help to explain how colour intensity is maintained in a fully expanded chromatophore when the pigment granules are distributed maximally: (i) pigment layers as thin as three granules that maintain optical effectiveness and (ii) the presence of high-refractive-index proteins—reflectin and crystallin—in granules. The latter discovery, combined with our finding that isolated chromatophore pigment granules fluoresce between 650 and 720 nm, refutes the prevailing hypothesis that cephalopod chromatophores are exclusively pigmentary organs composed solely of ommochromes. Perturbations to granular architecture alter optical properties, illustrating a role for nanostructure...
Lophius americanus Cuvier & Valenciennes 1837 (1), the goosefish, anglerfish, or monkfish, is com... more Lophius americanus Cuvier & Valenciennes 1837 (1), the goosefish, anglerfish, or monkfish, is common in coastal waters of the northeastern United States. Its geographic range extends from the northern Gulf of St. Lawrence south to Cape Hatteras, North Carolina (2, 3). The highest fish concentrations are found along the shallower depths of the shelf from 70 to 100 m, but there is also a significant deep-water population below 190 m. Adult fish migrate seasonally in response to spawning, food availability, and optimal temperatures (3°-9°C) (2). The species is also dispersed through the drifting of egg rafts. Total dispersal time from embryonic development through larval and juvenile stages can extend to several months until benthic recruitment occurs. Sexual maturity is reached between 3 and 4 years of age (3). Goosefish is the fourth largest commercial species in the U.S. fishery, and number one in demersal species landings. Goosefish landings have risen steeply through the 1980s, reaching approximately 28,800 mt ($35 million) for 1997 (4). Since the 1980s, the Canadian contribution to the fishery has declined precipitously, and now the major landings occur in the southern regions of the species range. In their autumn survey data, the Northeast Fisheries Science Center, Woods Hole, Massachusetts, has documented recent sharp declines in goosefish abundance, from 2.24 kg/tow in 1986 to 0.74 kg/tow in 1996. The New England and Mid-Atlantic Fishery Management Councils (NEFMC and MAFMC) consequently designated goosefish as overexploited and at low abundance (5). The 23rd Stock Assessment Workshop at the Northeast Fisheries Science Center concluded that it was not possible to delineate the stock structure for goosefish because of the lack of genetic, tagging, or migration studies. Nevertheless, the Councils divided the coastal population into northern and southern stocks (41°N latitude) for stock management purposes. This formula led to fishing restrictions being placed geographically, and made certain areas uneconomical to fish. Because of the lack of definitive stock data for goosefish (5), we undertook a population genetic study of goosefish in eastern waters from the Canadian border to North Carolina. We used random amplification of polymorphic DNA and PCR (RAPD-PCR) (6) to analyze the genetic structure of the sampled populations. Eight representative sampling sites were chosen, extending from Maine (42°40Ј N, 68°20Ј W) to North Carolina (35°40Ј, 75°00Ј), from depths to about 300 m. Fish were collected from September 1999 to June 2000. Up to 45 fish were sampled at each location. Tissue samples were collected in tissue preservation buffer (7). Genomic DNA was purified by standard phenol-chloroform procedures, and was finally dissolved in Tris-EDTA (TE) buffer (8). DNA fingerprinting was performed by RAPD-PCR (6), using 10
In many neurodegenerative disorders that lead to memory loss and dementia, the brain pathology re... more In many neurodegenerative disorders that lead to memory loss and dementia, the brain pathology responsible for neuronal loss is marked by accumulations of proteins in the form of extracellular plaques and intracellular filamentous tangles, containing hyperphosphorylated cytoskeletal proteins. These are assumed to arise as a consequence of deregulation of a normal pattern of topographic phosphorylation-that is, an abnormal shift of cytoskeletal protein phosphorylation from the normal axonal compartment to cell bodies. Although decades of studies have been directed to this problem, biochemical approaches in mammalian systems are limited: neurons are too small to permit separation of cell body and axon compartments. Since the pioneering studies of Hodgkin and Huxley on the giant fiber system of the squid, however, the stellate ganglion and its giant axons have been the focus of a large literature on the physiology and biochemistry of neuron function. This review concentrates on a host of studies in our laboratory and others on the factors regulating compartment-specific patterns of cytoskeletal protein phosphorylation (primarily neurofilaments) in an effort to establish a normal baseline of information for further studies on neurodegeneration. On the basis of these data, a model of topographic regulation is proposed that offers several possibilities for further studies on potential sites of deregulation that may lead to pathologies resembling those seen in mammalian and human brains showing neurodegeneration, dementia, and neuronal cell death.
Bryostatin, a potent agonist of protein kinase C (PKC), when administered to Hermissenda was foun... more Bryostatin, a potent agonist of protein kinase C (PKC), when administered to Hermissenda was found to affect acquisition of an associative learning paradigm. Low bryostatin concentrations (0.1 to 0.5 ng/ml) enhanced memory acquisition, while concentrations higher than 1.0 ng/ml down-regulated the pathway and no recall of the associative training was exhibited. The extent of enhancement depended upon the conditioning regime used and the memory stage normally fostered by that regime. The effects of two training events (TEs) with paired conditioned and unconditioned stimuli, which standardly evoked only short-term memory (STM) lasting 7 min, were-when bryostatin was added concurrently-enhanced to a long-term memory (LTM) that lasted about 20 h. The effects of both 4-and 6-paired TEs (which by themselves did not generate LTM), were also enhanced by bryostatin to induce a consolidated memory (CM) that lasted at least 5 days. The standard positive 9-TE regime typically produced a CM lasting at least 6 days. Low concentrations of bryostatin (Ͻ0.5 ng/ml) elicited no demonstrable enhancement of CM from 9-TEs. However, animals exposed to bryostatin concentrations higher than 1.0 ng/ml exhibited no behavioral learning.
RNA-binding protein BrunoL1 mediates translational stimulation of specific mRNAs including cenp-a... more RNA-binding protein BrunoL1 mediates translational stimulation of specific mRNAs including cenp-a and cyclinA2 via interactions with eIF3:
Cephalopod mollusks are renowned for their colorful and dynamic body patterns, produced by an ass... more Cephalopod mollusks are renowned for their colorful and dynamic body patterns, produced by an assemblage of skin components that interact with light. These may include iridophores, leucophores, chromatophores and (in some species) photophores. Here, we present molecular evidence suggesting that cephalopod chromatophores - small dermal pigmentary organs that reflect various colors of light - are photosensitive. RT-PCR revealed the presence of transcripts encoding rhodopsin and retinochrome within the retinas and skin of the squid Doryteuthis pealeii, and the cuttlefish Sepia officinalis and Sepia latimanus. In D. pealeii, Gqα and squid TRP channel transcripts were present in the retina and in all dermal samples. Rhodopsin, retinochrome and Gqα transcripts were also found in RNA extracts from dissociated chromatophores isolated from D. pealeii dermal tissues. Immunohistochemical staining labeled rhodopsin, retinochrome and Gqα proteins in several chromatophore components, including pi...
In Lymnaea stagnalis, in order to obtain a 10 min short-term memory (STM) of taste avoidance cond... more In Lymnaea stagnalis, in order to obtain a 10 min short-term memory (STM) of taste avoidance conditioning (TAC) at least 10 paired presentations of a conditioned stimulus (CS), sucrose, and an unconditioned stimulus (US), tactile stimulation to the animal's head, are required. Pre-exposure of snails to the protein kinase C (PKC) α and ε activator bryostatin (Bryo) facilitated STM formation in that only 5 paired CS-US trials were required. Typically 20 paired presentations of the CS-US are required for formation of STM and LTM. However, 20 paired presentations do not result in STM or LTM if snails are pre-incubated with a PKC inhibitor, Ro-32-0432. We also found that LTM lasting longer than 48 h was acquired with Bryo incubation for 45 min even after termination of the conditioning paradigm. These data suggest that activation of the α and ε isozymes of PKC is crucially involved in the formation of LTM and provide further support for a mechanism that has been conserved across the evolution of species ranging from invertebrate molluscs to higher mammals.
Cuttlefish, Sepia officinalis , possess neurally controlled, pigmented chromatophore organs that ... more Cuttlefish, Sepia officinalis , possess neurally controlled, pigmented chromatophore organs that allow rapid changes in skin patterning and coloration in response to visual cues. This process of adaptive coloration is enabled by the 500% change in chromatophore surface area during actuation. We report two adaptations that help to explain how colour intensity is maintained in a fully expanded chromatophore when the pigment granules are distributed maximally: (i) pigment layers as thin as three granules that maintain optical effectiveness and (ii) the presence of high-refractive-index proteins—reflectin and crystallin—in granules. The latter discovery, combined with our finding that isolated chromatophore pigment granules fluoresce between 650 and 720 nm, refutes the prevailing hypothesis that cephalopod chromatophores are exclusively pigmentary organs composed solely of ommochromes. Perturbations to granular architecture alter optical properties, illustrating a role for nanostructure...
Lophius americanus Cuvier & Valenciennes 1837 (1), the goosefish, anglerfish, or monkfish, is com... more Lophius americanus Cuvier & Valenciennes 1837 (1), the goosefish, anglerfish, or monkfish, is common in coastal waters of the northeastern United States. Its geographic range extends from the northern Gulf of St. Lawrence south to Cape Hatteras, North Carolina (2, 3). The highest fish concentrations are found along the shallower depths of the shelf from 70 to 100 m, but there is also a significant deep-water population below 190 m. Adult fish migrate seasonally in response to spawning, food availability, and optimal temperatures (3°-9°C) (2). The species is also dispersed through the drifting of egg rafts. Total dispersal time from embryonic development through larval and juvenile stages can extend to several months until benthic recruitment occurs. Sexual maturity is reached between 3 and 4 years of age (3). Goosefish is the fourth largest commercial species in the U.S. fishery, and number one in demersal species landings. Goosefish landings have risen steeply through the 1980s, reaching approximately 28,800 mt ($35 million) for 1997 (4). Since the 1980s, the Canadian contribution to the fishery has declined precipitously, and now the major landings occur in the southern regions of the species range. In their autumn survey data, the Northeast Fisheries Science Center, Woods Hole, Massachusetts, has documented recent sharp declines in goosefish abundance, from 2.24 kg/tow in 1986 to 0.74 kg/tow in 1996. The New England and Mid-Atlantic Fishery Management Councils (NEFMC and MAFMC) consequently designated goosefish as overexploited and at low abundance (5). The 23rd Stock Assessment Workshop at the Northeast Fisheries Science Center concluded that it was not possible to delineate the stock structure for goosefish because of the lack of genetic, tagging, or migration studies. Nevertheless, the Councils divided the coastal population into northern and southern stocks (41°N latitude) for stock management purposes. This formula led to fishing restrictions being placed geographically, and made certain areas uneconomical to fish. Because of the lack of definitive stock data for goosefish (5), we undertook a population genetic study of goosefish in eastern waters from the Canadian border to North Carolina. We used random amplification of polymorphic DNA and PCR (RAPD-PCR) (6) to analyze the genetic structure of the sampled populations. Eight representative sampling sites were chosen, extending from Maine (42°40Ј N, 68°20Ј W) to North Carolina (35°40Ј, 75°00Ј), from depths to about 300 m. Fish were collected from September 1999 to June 2000. Up to 45 fish were sampled at each location. Tissue samples were collected in tissue preservation buffer (7). Genomic DNA was purified by standard phenol-chloroform procedures, and was finally dissolved in Tris-EDTA (TE) buffer (8). DNA fingerprinting was performed by RAPD-PCR (6), using 10
In many neurodegenerative disorders that lead to memory loss and dementia, the brain pathology re... more In many neurodegenerative disorders that lead to memory loss and dementia, the brain pathology responsible for neuronal loss is marked by accumulations of proteins in the form of extracellular plaques and intracellular filamentous tangles, containing hyperphosphorylated cytoskeletal proteins. These are assumed to arise as a consequence of deregulation of a normal pattern of topographic phosphorylation-that is, an abnormal shift of cytoskeletal protein phosphorylation from the normal axonal compartment to cell bodies. Although decades of studies have been directed to this problem, biochemical approaches in mammalian systems are limited: neurons are too small to permit separation of cell body and axon compartments. Since the pioneering studies of Hodgkin and Huxley on the giant fiber system of the squid, however, the stellate ganglion and its giant axons have been the focus of a large literature on the physiology and biochemistry of neuron function. This review concentrates on a host of studies in our laboratory and others on the factors regulating compartment-specific patterns of cytoskeletal protein phosphorylation (primarily neurofilaments) in an effort to establish a normal baseline of information for further studies on neurodegeneration. On the basis of these data, a model of topographic regulation is proposed that offers several possibilities for further studies on potential sites of deregulation that may lead to pathologies resembling those seen in mammalian and human brains showing neurodegeneration, dementia, and neuronal cell death.
Bryostatin, a potent agonist of protein kinase C (PKC), when administered to Hermissenda was foun... more Bryostatin, a potent agonist of protein kinase C (PKC), when administered to Hermissenda was found to affect acquisition of an associative learning paradigm. Low bryostatin concentrations (0.1 to 0.5 ng/ml) enhanced memory acquisition, while concentrations higher than 1.0 ng/ml down-regulated the pathway and no recall of the associative training was exhibited. The extent of enhancement depended upon the conditioning regime used and the memory stage normally fostered by that regime. The effects of two training events (TEs) with paired conditioned and unconditioned stimuli, which standardly evoked only short-term memory (STM) lasting 7 min, were-when bryostatin was added concurrently-enhanced to a long-term memory (LTM) that lasted about 20 h. The effects of both 4-and 6-paired TEs (which by themselves did not generate LTM), were also enhanced by bryostatin to induce a consolidated memory (CM) that lasted at least 5 days. The standard positive 9-TE regime typically produced a CM lasting at least 6 days. Low concentrations of bryostatin (Ͻ0.5 ng/ml) elicited no demonstrable enhancement of CM from 9-TEs. However, animals exposed to bryostatin concentrations higher than 1.0 ng/ml exhibited no behavioral learning.
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Papers by M. Kuzirian