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Chet C Sherwood - One of the best experts on this subject based on the ideXlab platform.
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divergent lactate dehydrogenase isoenzyme profile in cellular compartments of primate forebrain structures
Molecular and Cellular Neuroscience, 2017Co-Authors: Tetyana Duka, Zachary Collins, Sarah M Anderson, Mary Ann Raghanti, John J Ely, Patrick R Hof, Derek E Wildman, Morris Goodman, Lawrence I Grossman, Chet C SherwoodAbstract:The compartmentalization and association of lactate dehydrogenase (LDH) with specific cellular structures (e.g., synaptosomal, sarcoplasmic or mitochondrial) may play an important role in brain energy metabolism. Our previous research revealed that LDH in the synaptosomal fraction shifts toward the aerobic isoforms (LDH-B) among the large-brained haplorhine primates compared to strepsirrhines. Here, we further analyzed the subcellular localization of LDH in primate forebrain structures using quantitative Western blotting and ELISA. We show that, in cytosolic and mitochondrial subfractions, LDH-B expression level was relatively elevated and LDH-A declined in haplorhines compared to strepsirrhines. LDH-B expression in mitochondrial fractions of the neocortex was preferentially increased, showing a particularly significant rise in the ratio of LDH-B to LDH-A in chimpanzees and humans. We also found a significant correlation between the protein levels of LDH-B in mitochondrial fractions from haplorhine neocortex and the synaptosomal LDH-B that suggests LDH isoforms shift from a predominance of A-subunits toward B-subunits as part of a system that spatially buffers dynamic energy requirements of brain cells. Our results indicate that there is differential subcellular compartmentalization of LDH isoenzymes that evolved among different primate lineages to meet the energy requirements in neocortical and striatal cells.
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synaptosomal lactate dehydrogenase isoenzyme composition is shifted toward aerobic forms in primate brain evolution
Brain Behavior and Evolution, 2014Co-Authors: Tetyana Duka, Zachary Collins, Sarah M Anderson, Mary Ann Raghanti, John J Ely, Patrick R Hof, Derek E Wildman, Morris Goodman, Lawrence I Grossman, Chet C SherwoodAbstract:With the evolution of a relatively large brain size in haplorhine primates (i.e. tarsiers, monkeys, apes, and humans), there have been associated changes in the molecular machinery that delivers energy to the neocortex. Here we investigated variation in lactate dehydrogenase (LDH) expression and isoenzyme composition of the neocortex and striatum in primates using quantitative Western blotting and isoenzyme analysis of total homogenates and synaptosomal fractions. Analysis of isoform expression revealed that LDH in synaptosomal fractions from both forebrain regions shifted towards a predominance of the heart-type, aerobic isoform LDH-B among haplorhines as compared to strepsirrhines (i.e. lorises and lemurs), while in the total homogenate of the neocortex and striatum there was no significant difference in LDH isoenzyme composition between the primate suborders. The largest increase occurred in synapse-associated LDH-B expression in the neocortex, with an especially remarkable elevation in the ratio of LDH-B/LDH-A in humans. The phylogenetic variation in the ratio of LDH-B/LDH-A was correlated with species-typical brain mass but not the encephalization quotient. A significant LDH-B increase in the subneuronal fraction from haplorhine neocortex and striatum suggests a relatively higher rate of aerobic glycolysis that is linked to synaptosomal mitochondrial metabolism. Our results indicate that there is a differential composition of LDH isoenzymes and metabolism in synaptic terminals that evolved in primates to meet increased energy requirements in association with brain enlargement.
Eric Hunter - One of the best experts on this subject based on the ideXlab platform.
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Elevated Rate of Fixation of Endogenous Retroviral Elements in Haplorhini TRIM5 and TRIM22 Genomic Sequences: Impact on Transcriptional Regulation
2016Co-Authors: William E. Diehl, Welkin E. Johnson, Eric HunterAbstract:All genes in the TRIM6/TRIM34/TRIM5/TRIM22 locus are type I interferon inducible, with TRIM5 and TRIM22 possessing antiviral properties. Evolutionary studies involving the TRIM6/34/5/22 locus have predominantly focused on the coding sequence of the genes, finding that TRIM5 and TRIM22 have undergone high rates of both non-synonymous nucleotide replacements and in-frame insertions and deletions. We sought to understand if divergent evolutionary pressures on TRIM6/ 34/5/22 coding regions have selected for modifications in the non-coding regions of these genes and explore whether such non-coding changes may influence the biological function of these genes. The transcribed genomic regions, including the introns, of TRIM6, TRIM34, TRIM5, and TRIM22 from ten Haplorhini primates and one prosimian species were analyzed for transposable element content. In Haplorhini species, TRIM5 displayed an exaggerated interspecies variability, predominantly resulting from changes in the composition of transposable elements in the large first and fourth introns. Multiple lineage-specific endogenous retroviral long terminal repeats (LTRs) were identified in the first intron of TRIM5 and TRIM22. In the prosimian genome, we identified a duplication of TRIM5 with a concomitant loss of TRIM22. The transposable element content of the prosimian TRIM5 genes appears to largely represent the shared Haplorhini/prosimian ancestral state for this gene. Furthermore, we demonstrated that one such differentially fixed LTR provides for species-specific transcriptional regulation of TRIM22 in response to p53 activation. Our results identify a previously unrecognized source of species-specifi
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elevated rate of fixation of endogenous retroviral elements in Haplorhini trim5 and trim22 genomic sequences impact on transcriptional regulation
PLOS ONE, 2013Co-Authors: William E. Diehl, Welkin E. Johnson, Eric HunterAbstract:All genes in the TRIM6/TRIM34/TRIM5/TRIM22 locus are type I interferon inducible, with TRIM5 and TRIM22 possessing antiviral properties. Evolutionary studies involving the TRIM6/34/5/22 locus have predominantly focused on the coding sequence of the genes, finding that TRIM5 and TRIM22 have undergone high rates of both non-synonymous nucleotide replacements and in-frame insertions and deletions. We sought to understand if divergent evolutionary pressures on TRIM6/34/5/22 coding regions have selected for modifications in the non-coding regions of these genes and explore whether such non-coding changes may influence the biological function of these genes. The transcribed genomic regions, including the introns, of TRIM6, TRIM34, TRIM5, and TRIM22 from ten Haplorhini primates and one prosimian species were analyzed for transposable element content. In Haplorhini species, TRIM5 displayed an exaggerated interspecies variability, predominantly resulting from changes in the composition of transposable elements in the large first and fourth introns. Multiple lineage-specific endogenous retroviral long terminal repeats (LTRs) were identified in the first intron of TRIM5 and TRIM22. In the prosimian genome, we identified a duplication of TRIM5 with a concomitant loss of TRIM22. The transposable element content of the prosimian TRIM5 genes appears to largely represent the shared Haplorhini/prosimian ancestral state for this gene. Furthermore, we demonstrated that one such differentially fixed LTR provides for species-specific transcriptional regulation of TRIM22 in response to p53 activation. Our results identify a previously unrecognized source of species-specific variation in the antiviral TRIM genes, which can lead to alterations in their transcriptional regulation. These observations suggest that there has existed long-term pressure for exaptation of retroviral LTRs in the non-coding regions of these genes. This likely resulted from serial viral challenges and provided a mechanism for rapid alteration of transcriptional regulation. To our knowledge, this represents the first report of persistent evolutionary pressure for the capture of retroviral LTR insertions.
Christopher E Kirk - One of the best experts on this subject based on the ideXlab platform.
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new middle eocene omomyines primates Haplorhini from san diego county california
Journal of Human Evolution, 2018Co-Authors: Amy L Atwater, Christopher E KirkAbstract:Abstract The Friars Formation of San Diego County, California, has yielded a middle Eocene mammalian fauna from the early part of the Uintan North American Land Mammal Age. Prior research on the primate fauna from the Friars Formation provides evidence of one notharctine and multiple omomyine species, but many specimens collected since the early 1980s remain unstudied. Here we describe three new omomyine genera from the Friars Formation. These new taxa range in estimated body mass from about 119 g to 757 g, and substantially expand the diversity of middle Eocene omomyoids known from Southern California. Resolution of the phylogenetic relationships of the new Friars Formation omomyines is complicated by the fact that different character-taxon matrices and tree building methods produce different results. Nevertheless, all preliminary phylogenetic analyses are congruent in recovering a close relationship between the three new genera and the omomyines Macrotarsius , Omomys , Ourayia , and Utahia . Prior research has documented a shift in omomyoid diversity in North America from the anantomophine-rich Bridgerian to the omomyine-rich Uintan. Our description of three new Uintan omomyine taxa from the Friars Formation further emphasizes these opposite trends in anaptomorphine and omomyine species richness during the middle Eocene. All three of the new taxa are currently known from only the Friars Formation in San Diego County, California. Four of the previously known omomyoid genera from Southern California ( Dyseolemur, Chumashius, Yaquius, and Stockia ) are also endemic to the region, further highlighting the provincial character of primate faunas in Utah, Southern California, and West Texas during the Uintan.
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internal carotid arterial canal size and scaling in euarchonta re assessing implications for arterial patency and phylogenetic relationships in early fossil primates
Journal of Human Evolution, 2016Co-Authors: Doug M. Boyer, Christopher E Kirk, Mary T Silcox, Gregg F Gunnell, Christopher C Gilbert, Gabriel S YapuncichAbstract:Primate species typically differ from other mammals in having bony canals that enclose the branches of the internal carotid artery (ICA) as they pass through the middle ear. The presence and relative size of these canals varies among major primate clades. As a result, differences in the anatomy of the canals for the promontorial and stapedial branches of the ICA have been cited as evidence of either haplorhine or strepsirrhine affinities among otherwise enigmatic early fossil euprimates. Here we use micro X-ray computed tomography to compile the largest quantitative dataset on ICA canal sizes. The data suggest greater variation of the ICA canals within some groups than has been previously appreciated. For example, Lepilemur and Avahi differ from most other lemuriforms in having a larger promontorial canal than stapedial canal. Furthermore, various lemurids are intraspecifically variable in relative canal size, with the promontorial canal being larger than the stapedial canal in some individuals but not others. In species where the promontorial artery supplies the brain with blood, the size of the promontorial canal is significantly correlated with endocranial volume (ECV). Among species with alternate routes of encephalic blood supply, the promontorial canal is highly reduced relative to ECV, and correlated with both ECV and cranium size. Ancestral state reconstructions incorporating data from fossils suggest that the last common ancestor of living primates had promontorial and stapedial canals that were similar to each other in size and large relative to ECV. We conclude that the plesiomorphic condition for crown primates is to have a patent promontorial artery supplying the brain and a patent stapedial artery for various non-encephalic structures. This inferred ancestral condition is exhibited by treeshrews and most early fossil euprimates, while extant primates exhibit reduction in one canal or another. The only early fossils deviating from this plesiomorphic condition are Adapis parisiensis with a reduced promontorial canal, and Rooneyia and Mahgarita with reduced stapedial canals.
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American Journal of Primatology 71:1–10 (2009) RESEARCH ARTICLE Visual Acuity in the Cathemeral Strepsirrhine Eulemur macaco flavifrons
2015Co-Authors: Carrie C. Veilleux, Christopher E KirkAbstract:Studies of visual acuity in primates have shown that diurnal haplorhines have higher acuity (30–75 cycles per degree (c/deg)) than most other mammals. However, relatively little is known about visual acuity in non-haplorhine primates, and published estimates are only available for four strepsirrhine genera (Microcebus, Otolemur, Galago, and Lemur). We present here the first measurements of visual acuity in a cathemeral strepsirrhine species, the blue-eyed black lemur (Eulemur macaco flavifrons). Acuity in two subjects, a 3-year-old male and a 16-year-old female, was assessed behaviorally using a two-alternative forced choice discrimination task. Visual stimuli consisted of high contrast square wave gratings of seven spatial frequencies. Acuity threshold was determined using a 70 % correct response criterion. Results indicate a maximum visual acuity of 5.1 c/deg for the female (1718 trials) and 3.8 c/deg for the male (846 trials). These values for E. macaco are slightly lower than those reported for diurnal Lemur catta, and are generally comparable to those reported for nocturnal Microcebus murinus and Otolemur crassicaudatus. To examine ecological sources of variation in primate visual acuity, we also calculated maximum theoretical acuity for Cheirogaleus medius (2.8 c/deg) and Tarsius syrichta (8.9 c/deg) using published data on retinal ganglion cell density and eye morphology. These data suggest that visual acuity in primates may be influenced by activity pattern, diet, and phylogenetic history. In particular, the relatively high acuity of T. syrichta and Galago senegalensis suggests that visual predation may be an important selective factor favoring high visual acuity in primates. Am. J. Primatol
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Visual acuity in the cathemeral strepsirrhine Eulemur macaco flavifrons
2009Co-Authors: Carrie C. Veilleux, Christopher E Kirk, Am J Primatol, / Veilleux, Christopher KirkAbstract:Studies of visual acuity in primates have shown that diurnal haplorhines have higher acuity (30-75 cycles per degree (c/deg)) than most other mammals. However, relatively little is known about visual acuity in non-haplorhine primates, and published estimates are only available for four strepsirrhine genera (Microcebus, Otolemur, Galago, and Lemur). We present here the first measurements of visual acuity in a cathemeral strepsirrhine species, the blue-eyed black lemur (Eulemur macaco flavifrons). Acuity in two subjects, a 3-year-old male and a 16-year-old female, was assessed behaviorally using a two-alternative forced choice discrimination task. Visual stimuli consisted of high contrast square wave gratings of seven spatial frequencies. Acuity threshold was determined using a 70% correct response criterion. Results indicate a maximum visual acuity of 5.1 c/deg for the female (1718 trials) and 3.8 c/deg for the male (846 trials). These values for E. macaco are slightly lower than those reported for diurnal Lemur catta, and are generally comparable to those reported for nocturnal Microcebus murinus and Otolemur crassicaudatus. To examine ecological sources of variation in primate visual acuity, we also calculated maximum theoretical acuity for Cheirogaleus medius (2.8 c/deg) and Tarsius syrichta (8.9 c/deg) using published data on retinal ganglion cell density and eye morphology. These data suggest that visual acuity in primates may be influenced by activity pattern, diet, and phylogenetic history. In particular, the relatively high acuity of T. syrichta and Galago senegalensis suggests that visual predation may be an important selective factor favoring high visual acuity in primates. Am
Amy L Atwater - One of the best experts on this subject based on the ideXlab platform.
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new middle eocene omomyines primates Haplorhini from san diego county california
Journal of Human Evolution, 2018Co-Authors: Amy L Atwater, Christopher E KirkAbstract:Abstract The Friars Formation of San Diego County, California, has yielded a middle Eocene mammalian fauna from the early part of the Uintan North American Land Mammal Age. Prior research on the primate fauna from the Friars Formation provides evidence of one notharctine and multiple omomyine species, but many specimens collected since the early 1980s remain unstudied. Here we describe three new omomyine genera from the Friars Formation. These new taxa range in estimated body mass from about 119 g to 757 g, and substantially expand the diversity of middle Eocene omomyoids known from Southern California. Resolution of the phylogenetic relationships of the new Friars Formation omomyines is complicated by the fact that different character-taxon matrices and tree building methods produce different results. Nevertheless, all preliminary phylogenetic analyses are congruent in recovering a close relationship between the three new genera and the omomyines Macrotarsius , Omomys , Ourayia , and Utahia . Prior research has documented a shift in omomyoid diversity in North America from the anantomophine-rich Bridgerian to the omomyine-rich Uintan. Our description of three new Uintan omomyine taxa from the Friars Formation further emphasizes these opposite trends in anaptomorphine and omomyine species richness during the middle Eocene. All three of the new taxa are currently known from only the Friars Formation in San Diego County, California. Four of the previously known omomyoid genera from Southern California ( Dyseolemur, Chumashius, Yaquius, and Stockia ) are also endemic to the region, further highlighting the provincial character of primate faunas in Utah, Southern California, and West Texas during the Uintan.
Tetyana Duka - One of the best experts on this subject based on the ideXlab platform.
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divergent lactate dehydrogenase isoenzyme profile in cellular compartments of primate forebrain structures
Molecular and Cellular Neuroscience, 2017Co-Authors: Tetyana Duka, Zachary Collins, Sarah M Anderson, Mary Ann Raghanti, John J Ely, Patrick R Hof, Derek E Wildman, Morris Goodman, Lawrence I Grossman, Chet C SherwoodAbstract:The compartmentalization and association of lactate dehydrogenase (LDH) with specific cellular structures (e.g., synaptosomal, sarcoplasmic or mitochondrial) may play an important role in brain energy metabolism. Our previous research revealed that LDH in the synaptosomal fraction shifts toward the aerobic isoforms (LDH-B) among the large-brained haplorhine primates compared to strepsirrhines. Here, we further analyzed the subcellular localization of LDH in primate forebrain structures using quantitative Western blotting and ELISA. We show that, in cytosolic and mitochondrial subfractions, LDH-B expression level was relatively elevated and LDH-A declined in haplorhines compared to strepsirrhines. LDH-B expression in mitochondrial fractions of the neocortex was preferentially increased, showing a particularly significant rise in the ratio of LDH-B to LDH-A in chimpanzees and humans. We also found a significant correlation between the protein levels of LDH-B in mitochondrial fractions from haplorhine neocortex and the synaptosomal LDH-B that suggests LDH isoforms shift from a predominance of A-subunits toward B-subunits as part of a system that spatially buffers dynamic energy requirements of brain cells. Our results indicate that there is differential subcellular compartmentalization of LDH isoenzymes that evolved among different primate lineages to meet the energy requirements in neocortical and striatal cells.
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synaptosomal lactate dehydrogenase isoenzyme composition is shifted toward aerobic forms in primate brain evolution
Brain Behavior and Evolution, 2014Co-Authors: Tetyana Duka, Zachary Collins, Sarah M Anderson, Mary Ann Raghanti, John J Ely, Patrick R Hof, Derek E Wildman, Morris Goodman, Lawrence I Grossman, Chet C SherwoodAbstract:With the evolution of a relatively large brain size in haplorhine primates (i.e. tarsiers, monkeys, apes, and humans), there have been associated changes in the molecular machinery that delivers energy to the neocortex. Here we investigated variation in lactate dehydrogenase (LDH) expression and isoenzyme composition of the neocortex and striatum in primates using quantitative Western blotting and isoenzyme analysis of total homogenates and synaptosomal fractions. Analysis of isoform expression revealed that LDH in synaptosomal fractions from both forebrain regions shifted towards a predominance of the heart-type, aerobic isoform LDH-B among haplorhines as compared to strepsirrhines (i.e. lorises and lemurs), while in the total homogenate of the neocortex and striatum there was no significant difference in LDH isoenzyme composition between the primate suborders. The largest increase occurred in synapse-associated LDH-B expression in the neocortex, with an especially remarkable elevation in the ratio of LDH-B/LDH-A in humans. The phylogenetic variation in the ratio of LDH-B/LDH-A was correlated with species-typical brain mass but not the encephalization quotient. A significant LDH-B increase in the subneuronal fraction from haplorhine neocortex and striatum suggests a relatively higher rate of aerobic glycolysis that is linked to synaptosomal mitochondrial metabolism. Our results indicate that there is a differential composition of LDH isoenzymes and metabolism in synaptic terminals that evolved in primates to meet increased energy requirements in association with brain enlargement.
