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Impact Of The Soft-Shell Clam Mya Arenaria On Sulfate Reduction In An Intertidal Sediment, Kim Hansen, Gary M. King, Erik Kristensen May 1996

Impact Of The Soft-Shell Clam Mya Arenaria On Sulfate Reduction In An Intertidal Sediment, Kim Hansen, Gary M. King, Erik Kristensen

Faculty Publications

Sulfate reduction and various parameters related to the sulfur cycle were examined at mm to cm scales around burrows of the soft-shell clam Mya arenaria in an intertidal sediment (Lowes Cove, Maine, USA). Sulfate reduction rates were 1.5 to 2 times higher in the inner 1 to 5 mm region surrounding the burrow than in ambient sediment In contrast, pools of reduced sulfur increased with the distance from the burrow wall to values ≈1.5 times higher in ambient sediment. The highest numbers of sulfate-reducing bacteria (estimated using a most-probable-number technique) and microbial biomass (estimated from phospholipid phosphorous content) relative to …

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Urea Production And Turnover Following The Addition Of Amp, Cmp, Rna And A Protein Mixture To A Marine Sediment, Mette S. Therkildsen, Gary M. King, Bente Aa Lomstein May 1996

Urea Production And Turnover Following The Addition Of Amp, Cmp, Rna And A Protein Mixture To A Marine Sediment, Mette S. Therkildsen, Gary M. King, Bente Aa Lomstein

Faculty Publications

The potential of adenosine 5′-monophosphate (AMP), cytidine 5′-monophosphate (CMP), 16S ribosomal RNA, and a protein (bovine serum albumin) to serve as substrates for bacterial urea production was evaluated in a defaunated, anoxic marine sediment. AMP, CMP and RNA stimulated urea production and urea turnover, but CMP to a lesser degree than AMP and RNA. The increase in urea production and turnover rates took place immediately after AMP, CMP, and RNA were added to the sediment. The rapid response in urea production and turnover rates suggests that the necessary uptake mechanisms and enzymes to utilize the substrates were present constitutively. Addition …

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Dna Sequences Of Alu Elements Indicate A Recent Replacement Of The Human Autosomal Genetic Complement, Alec Knight, Mark A. Batzer, Mark Stoneking, Hemant K. Tiwari, W. Douglas Scheer, Rene J. Herrera, Prescott L. Deininger Apr 1996

Dna Sequences Of Alu Elements Indicate A Recent Replacement Of The Human Autosomal Genetic Complement, Alec Knight, Mark A. Batzer, Mark Stoneking, Hemant K. Tiwari, W. Douglas Scheer, Rene J. Herrera, Prescott L. Deininger

Faculty Publications

DNA sequences of neutral nuclear autosomal loci, compared across diverse human populations, provide a previously untapped perspective into the mode and tempo of the emergence of modern humans and a critical comparison with published clonally inherited mitochondrial DNA and Y chromosome measurements of human diversity. We obtained over 55 kilobases of sequence from three autosomal loci encompassing Alu repeats for representatives of diverse human populations as well as orthologous sequences for other hominoid species at one of these loci. Nucleotide diversity was exceedingly low. Most individuals and populations were identical. Only a single nucleotide difference distinguished presumed ancestral alleles from …

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The Advanced Glycation End Product, NE-(Carboxymethyl)Lysine, Is A Product Of Both Lipid Peroxidation And Glycoxidation Reactions, Min-Xin Fu, Jesus R. Requena, Alicia J. Jenkins, Timothy J. Lyons, John W. Baynes, Suzanne R. Thorpe Apr 1996

The Advanced Glycation End Product, NE-(Carboxymethyl)Lysine, Is A Product Of Both Lipid Peroxidation And Glycoxidation Reactions, Min-Xin Fu, Jesus R. Requena, Alicia J. Jenkins, Timothy J. Lyons, John W. Baynes, Suzanne R. Thorpe

Faculty Publications

Nepsilon-(Carboxymethyl)lysine (CML) is an advanced glycation end product formed on protein by combined nonenzymatic glycation and oxidation (glycoxidation) reactions. We now report that CML is also formed during metal-catalyzed oxidation of polyunsaturated fatty acids in the presence of protein. During copper-catalyzed oxidation in vitro, the CML content of low density lipoprotein increased in concert with conjugated dienes but was independent of the presence of the Amadori compound, fructoselysine, on the protein. CML was also formed in a time-dependent manner in RNase incubated under aerobic conditions in phosphate buffer containing arachidonate or linoleate; only trace amounts of CML were formed from …

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A Home Of Her Own: (Writing) A Family Story Of Separation And Second Chances, Lisa M. Tillmann Ph.D. Apr 1996

A Home Of Her Own: (Writing) A Family Story Of Separation And Second Chances, Lisa M. Tillmann Ph.D.

Faculty Publications

On March 16, 1996, I interviewed my mother, Beth Tillmann, about her parents' divorce and her life as a foster child. From detailed notes taken during our phone conversation and from family stories told to me throughout my life, I constructed a narrative titled "A Home of Her Own." Its structure and tone mimic the way my mother speaks about the dissolution of her family of origin and her attachments to and separations from those who tried to help her rebuild a sense of home. After the story, I discuss what narrative representations of loss offer the writer, the participant, …

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Acute Depression Of Mitochondrial Protein Synthesis During Anoxia: Contributions Of Oxygen Sensing, Matrix Acidification, And Redox State, Kurt E. Kwast, Steven C. Hand Mar 1996

Acute Depression Of Mitochondrial Protein Synthesis During Anoxia: Contributions Of Oxygen Sensing, Matrix Acidification, And Redox State, Kurt E. Kwast, Steven C. Hand

Faculty Publications

Mitochondrial protein synthesis is acutely depressed during anoxia-induced quiescence in embryos of Artemia franciscana. Oxygen deprivation is accompanied in vivo by a dramatic drop in extramitochondrial pH, and both of these alterations strongly inhibit protein synthesis in isolated mitochondria. Here we show that the oxygen dependence is not explained simply by blockage of the electron transport chain or by the increased redox state. Whereas oxygen deprivation substantially depressed protein synthesis within 5 min and resulted in a 77% reduction after 1 h, aerobic incubations with saturating concentrations of cyanide or antimycin A had little effect during the first 20 min …

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Effects Of High-Molecular-Weight Dissolved Organic Matter On Nitrogen Dynamics In The Mississippi River Plume, Wayne S. Gardner, Ronald Benner, Rainer M.W. Amon, James B. Cotner Jr., Joann F. Cavaletto, Jeffrey R. Johnson Mar 1996

Effects Of High-Molecular-Weight Dissolved Organic Matter On Nitrogen Dynamics In The Mississippi River Plume, Wayne S. Gardner, Ronald Benner, Rainer M.W. Amon, James B. Cotner Jr., Joann F. Cavaletto, Jeffrey R. Johnson

Faculty Publications

The dynamics of N and its interactions with labile dissolved organic C (DOC), bacteria, and phytoplankton were studied to determine potential effects of dissolved organic matter (DOM) and light on N dynamics in surface waters of the Mississippi River (USA) plume in the Gulf of Mexico. Bacterial uptake of added labeled N compounds ( 15NH4+ or 15N-labeled dissolved free amino acids. DFAA) was stimulated more by high-molecular-weight (HMW, >l kDa) DOM than by low-molecular-weight (LMW, < l kDa) DOM. An index that inversely indicated the presence of labile DOC was defined as the fraction of assimilated Amino acid-15N that was Recovered as 15N -Ammonium (ANRA), following the additions of high-levels (4 µM) of 15N -DFAA. …

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Effects Of Assembly And Mutations Outside The Active Site On The Functional Ph Dependence Of Escherichia Coli Aspartate Transcarbamylase, Xiaoling Yuan, Vince J. Licata, Norma M. Allewell Jan 1996

Effects Of Assembly And Mutations Outside The Active Site On The Functional Ph Dependence Of Escherichia Coli Aspartate Transcarbamylase, Xiaoling Yuan, Vince J. Licata, Norma M. Allewell

Faculty Publications

Electrostatics are central to the function and regulation of Escherichia coli aspartate transcarbamylase, and modeling has suggested that long range electrostatic effects are likely to be important (Glackin, M. P., McCarthy, M. P., Mallikarachchi, D., Matthew, J. B., and Allewell, N. M. (1989) Proteins Struct. Funct. Genet. 5, 66-77; Oberoi, H., Trikha, J., Yuan, X., and Allewell, N. M. (1995) Proteins Struct. Funct. Genet., in press). To investigate this possibility from an experimental standpoint, we have examined the effects both of assembly and of removing ionizable and polar side chains outside the active site (Glu-50, Tyr-165, and Tyr-240) on the …

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Instructional Support And Demands: Helping Teachers Help Students Meet Increasing Academic Standards, Amy Strage, Robert G. Curley Jan 1996

Instructional Support And Demands: Helping Teachers Help Students Meet Increasing Academic Standards, Amy Strage, Robert G. Curley

Faculty Publications

Suggests a framework for pre-service and in-service teachers to help them think about the constellation of demands new policy initiatives would impose on students. Kinds of instructional supports; Compensations; Theme of problems; Re-examination of data.

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Infection And Fungal Development Of Tubakia Dryina On Sweet Gum (Liquidambar Styraciflua), Josephine Taylor, Shane Clark Jan 1996

Infection And Fungal Development Of Tubakia Dryina On Sweet Gum (Liquidambar Styraciflua), Josephine Taylor, Shane Clark

Faculty Publications

Infection and fungal development of Tubakia dryina were investigated on leaves of sweet gum using a combination of microscopic techniques. Conidia of T. dryina adhered to the leaf surface and formed septate germ tubes. Germ tubes terminated in small appressoria that formed directly over epidermal cells. Intra- and intercellular hyphae ramified extensively throughout the leaf tissue. Host cells associated with the infection site became necrotic and collapsed, resulting in macroscopic disease symptoms.

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Adaptations Facilitating Facultative Oophagy In The Gray Rat Snake, Elaphe Obsoleta Spiloides [Abstract], Stephen J. Mullin Jan 1996

Adaptations Facilitating Facultative Oophagy In The Gray Rat Snake, Elaphe Obsoleta Spiloides [Abstract], Stephen J. Mullin

Faculty Publications

No abstract provided.

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Dietary Overview Of Hemidactylus Turcicus With Possible Implications Of Food Partitioning, Daniel Saenz Jan 1996

Dietary Overview Of Hemidactylus Turcicus With Possible Implications Of Food Partitioning, Daniel Saenz

Faculty Publications

A stomach content analysis was conducted on Hemidactylus turcicus, the Mediterranean gecko, from 19 April 1990 to 15 October 1990, on the campus of Stephen F. Austin State University, Nacogdoches, Texas. Geckos (N = 167) were placed into four size groups based on snout-vent-length (5 29 mm, 30-39 mm, 40-49 mm, and z 50 mm) and three microhabitat groups based on perch height (those occupying perch sites < 1.52 m, 2 1.52 m to 5 3.05 m, and > 3.05 m). Stomach contents were analyzed and sex, size, and microhabitat groups were compared using Schoener's percent overlap index. Volumetrically, the most important prey items taken were Orthoptera, Lepidoptera, and Isopoda. Geckos of …

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Higher-Order Associative Processing In Hermissenda Suggests Multiple Sites Of Neuronal Modulation., Ronald F. Rogers, Louis D. Matzel Jan 1996

Higher-Order Associative Processing In Hermissenda Suggests Multiple Sites Of Neuronal Modulation., Ronald F. Rogers, Louis D. Matzel

Faculty Publications

Two important features of modern accounts of associative learning are (1) the capacity for contextual stimuli to serve as a signal for an unconditioned stimulus (US) and (2) the capacity for a previously conditioned (excitatory) stimulus to "block" learning about a redundant stimulus when both stimuli serve as a signal for the same US. Here, we examined the process of blocking, thought by some to reflect a cognitive aspect of classical conditioning, and its underlying mechanisms in the marine mollusc Hermissenda. In two behavioral experiments, a context defined by chemosensory stimuli was made excitatory by presenting unsignalled USs (rotation) in …

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Teaching The Elephant To Dance: Privatizing The Fda Review Process, Elizabeth Price Foley, Elizabeth C. Price Jan 1996

Teaching The Elephant To Dance: Privatizing The Fda Review Process, Elizabeth Price Foley, Elizabeth C. Price

Faculty Publications

Considers the implications of privatizing the Food and Drug Administration's (FDA) review of the safety and efficacy of medical devices and drugs. Concludes that the FDA's flaws - namely, a risk avoidance culture and autocratic style of regulation - can only be accomplished by breaking the agency's monopolization of this review function.

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Atta Texana, Texas Leaf-Cutting Ant, On Typic Quartzipsamments: Ecological Considerations, David L. Kulhavy, W. G. Ross, R. R. Cahal Iii Jan 1996

Atta Texana, Texas Leaf-Cutting Ant, On Typic Quartzipsamments: Ecological Considerations, David L. Kulhavy, W. G. Ross, R. R. Cahal Iii

Faculty Publications

Pine plantations on Typic Quartzipsamments in East Texas are difficult to establish. Forest management options following clearcutting are limited. An 8-year regeneration study of the growth and survival of loblolly, Pinus taeda, L. shortleaf, P. echinata Mill., slash, P. elliotii Engelm and longleaf pines P. palustris Mill. was conducted to determine optimum tree species and treatments for reforestation, and to recommend practical alternative land uses and management strategies for Typic Quartzipsamments. Successful regeneration provides new opportunities for insects and pathogens. Impacts of the Nantucket pine tip moth, R}iyacionia frustrana (Comstock), the Deodar weevil, Pissodes nemorensis, Germar, Annosus root rot, Heterobasidion …

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Red-Cockaded Woodpecker Nesting Success, Forest Structure, And Southern Flying Squirrels In Texas, Richard N. Conner, D. Craig Rudolph, Daniel Saenz, Richard R. Schaefer Jan 1996

Red-Cockaded Woodpecker Nesting Success, Forest Structure, And Southern Flying Squirrels In Texas, Richard N. Conner, D. Craig Rudolph, Daniel Saenz, Richard R. Schaefer

Faculty Publications

For several decades general opinion has suggested that southern flying squirrels (Gluucomys volans) have a negative effect on Red-cockaded Woodpeckers (Picoides borealis) through competition for cavities and egg/nestling predation. Complete removal of hardwood trees from Red-cockaded Woodpecker cavity tree clusters has occurred on some forests because southern flying squirrel abundance was presumed to be associated with the presence and abundance of hardwood vegetation. In some locations, southern flying squirrels have been captured and either moved or killed in the name of Red-cockaded Woodpecker management. We determined southern flying squirrel occupancy of Red-cockaded Woodpecker cavities in loblolly (Pinus taeda)-shortleaf (P. echinata) …

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Red-Cockaded Woodpeckers And Silvicultural Practice: Is Uneven-Aged? Silviculture Preferable To Even-Aged, D. Craig Rudolph, Richard N. Conner Jan 1996

Red-Cockaded Woodpeckers And Silvicultural Practice: Is Uneven-Aged? Silviculture Preferable To Even-Aged, D. Craig Rudolph, Richard N. Conner

Faculty Publications

The endangered red-cockaded woodpecker (Picoides borealis) has become a high-profile management issue in the southeastern United States. Suitable habitat consists of mature to old pine, or mixed pine-hardwood forest, with minimal hardwood midstory vegetation. Loss of habitat, detrimental silvicultural practices, and changes in the fire regime have resulted in small fragmented populations, most of which have been declining precipitously in recent decades (Costa and Escano 1989, Conner and Rudolph 1989). The current population of l0-12 thousand birds occurs across much of the original range from Virginia and Florida west to Oklahoma and Texas (James 1995). However, populations are restricted to …

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Deer Use Of Riparian Zones And Adjacent Pine Plantations In Texas, Micah L. Poteet, Ronald E. Thill, R. Montague Whiting Jr., R. Lee Rayburn Jan 1996

Deer Use Of Riparian Zones And Adjacent Pine Plantations In Texas, Micah L. Poteet, Ronald E. Thill, R. Montague Whiting Jr., R. Lee Rayburn

Faculty Publications

The authors monitored white-tailed deer (Odocoileus virginianus) use of riparian zones (RZ’s) and adjacent pine plantations of 3 age classes (young, 1 to 3 years old; intermediate, 5 to 7 years old; and older, 9 to 13 years old) using radio telemetry for 2 years on a 1,300 ha study area near Alto, TX. Riparian zones comprised 22.0 percent of the area; young, intermediate, and older pine plantations comprised 19.1 percent, 45.7 percent, and 13.2 percent, respectively. Based on data from 4 to 9 deer the first year and 12 to 17 deer the second year, home ranges averaged 103, …

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Effects Of Climate Change On Hypoxia In Coastal Waters: A Doubled Co2 Scenario For The Northern Gulf Of Mexico, D Justic, N N. Rabalais, R. Eugene Turner Jan 1996

Effects Of Climate Change On Hypoxia In Coastal Waters: A Doubled Co2 Scenario For The Northern Gulf Of Mexico, D Justic, N N. Rabalais, R. Eugene Turner

Faculty Publications

Projections of general circulation models suggest that freshwater discharge from the Mississippi River to the coastal ocean will increase 20% if atmospheric CO2 concentration doubles. This result is likely to affect water column stability, surface productivity, and global oxygen cycling in the northern Gulf of Mexico, which is the site of the largest (up to 16,500 km(2)) and most severe hypoxic zone (liter(-1)) in the western Atlantic Ocean. We use a coupled physical-biological two-box model to investigate potential effects of climate change on seasonal oxygen cycling and hypoxia in river-dominated coastal waters. The model was developed and calibrated using comprehensive …

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A New High Pressure Sapphire Nuclear Magnetic Resonance Cell, Shi Bai, Craig M. Taylor, Charles L. Mayne, Ronald J. Pugmire, David M. Grant Jan 1996

A New High Pressure Sapphire Nuclear Magnetic Resonance Cell, Shi Bai, Craig M. Taylor, Charles L. Mayne, Ronald J. Pugmire, David M. Grant

Faculty Publications

A new version of a single-crystal sapphire high pressure nuclear magnetic resonance (NMR) cell is described that is capable of controlling the sample pressure independent of the temperature. A movable piston inside the cell adjusts and controls the sample pressure from ambient conditions to 200 atm within plus or minus 0.3 atm. The linewidth at half-height for a 13C spectrum of carbon dioxide at 15degrees C and 57.8 atm is found to be 0.5 Hz. The carbon dioxide gas/liquid phase transition is clearly observed by measuring 13C chemical shifts as the sample pressure approaches equilibrium. The time required for this …

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Genetics Of Oviposition Success Of A Thelytokous Fairyfly Parasitoid, Anagrus Delicatus, James T. Cronin, Donald R. Strong Jan 1996

Genetics Of Oviposition Success Of A Thelytokous Fairyfly Parasitoid, Anagrus Delicatus, James T. Cronin, Donald R. Strong

Faculty Publications

The foraging behaviour of the salt-marsh parasitoid, Anagrus delicatus (Hymenoptera: Mymaridae), is distinguished by few eggs laid per patch of hosts and frequent dispersal among patches. We investigated the within-population genetic variability in six quantitative traits associated with this unusual behaviour: fecundity (lifetime number of eggs), time on a patch, number of ovipositions per patch, oviposition rate, ovipositor length and tibia length (a measure of body size). Forty-one wasp isolines were initiated from single parthenogenetic females from three isolated salt marshes, and were maintained for up to eight generations in the greenhouse. We estimated the genetic variance and broad-sense heritability …

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The Phytochrome Gene Family In Grasses (Poaceae): A Phylogeny And Evidence That Grasses Have A Subset Of The Loci Found In Dicot Angiosperms, S. Mathews, Robert A. Sharrock Jan 1996

The Phytochrome Gene Family In Grasses (Poaceae): A Phylogeny And Evidence That Grasses Have A Subset Of The Loci Found In Dicot Angiosperms, S. Mathews, Robert A. Sharrock

Faculty Publications

The phytochrome nuclear gene family encodes photoreceptor proteins that mediate developmental responses to red and far red light throughout the life of the plant. From studies of the dicot flowering plant Arabidopsis, the family has been modeled as comprising five loci, PHYA-PHYE. However, it has been shown recently that the Arabidopsis model may not completely represent some flowering plant groups because additional PHY loci related to PHYA and PHYB of Arabidopsis apparently have evolved independently several times in dicots, and monocot flowering plants may lack orthologs of PHYD and PHYE of Arabidopsis. Nonetheless, the phytochrome nucleotide data were informative in …

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Characterization Of The Denaturation And Renaturation Of Human Plasma Vitronectin I. Biophysical Characterization Of Protein Unfolding And Multimerization, Ping Zhuang, Michael N. Blackburn, Cynthia B. Peterson Jan 1996

Characterization Of The Denaturation And Renaturation Of Human Plasma Vitronectin I. Biophysical Characterization Of Protein Unfolding And Multimerization, Ping Zhuang, Michael N. Blackburn, Cynthia B. Peterson

Faculty Publications

Upon treatment with denaturing agents, vitronectin has been observed to exhibit conformational alterations which are similar to the structural changes detected when vitronectin binds the thrombin-antithrombin complex or associates with the terminal attack complex of complement. Denaturation and renaturation of vitronectin isolated from human plasma were characterized by changes in intrinsic fluorescence. Unfolding by chemical denaturants was irreversible and accompanied by self-association of the protein to form vitronectin multimers. Self-association was evaluated by equilibrium analytical ultracentrifugation which demonstrated that multimers form only during the refolding process after removal of denaturant, that multimeric vitronectin dissociates to constituent subunits readily upon treatment …

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The Ecological Origins And Consequences Of Cattle Ranching In Sixteenth-Century New Spain, Andrew Sluyter Jan 1996

The Ecological Origins And Consequences Of Cattle Ranching In Sixteenth-Century New Spain, Andrew Sluyter

Faculty Publications

Despite the dramatic landscape changes Mexico has undergone due to the introduction of cattle ranching by the Spaniards in the early sixteenth century, the ecological origins of that pastroecosystem have remained obscure. About 1521, Gregorio de Villalobos implanted an Andalusian-derived herding ecology in the Gulf Coast lowlands that involved seasonal movement of cattle between wetlands and hill lands. Land-grant records demonstrate that as the colonial economy expanded, the transhumant model proliferated and came into conflict with those native settlements that had survived the pandemics of the early sixteenth century. In circumventing viceregal laws meant to protect native cultures and ecologies, …

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Efficient Long-Pcr Site-Specific Mutagenesis Of A High Gc Template, Vladimir Chouljenko, Sukhanya Jayachandra, Galina Rybachuk, Konstantin G. Kousoulas Jan 1996

Efficient Long-Pcr Site-Specific Mutagenesis Of A High Gc Template, Vladimir Chouljenko, Sukhanya Jayachandra, Galina Rybachuk, Konstantin G. Kousoulas

Faculty Publications

A long-PCR method was developed for the efficient site-specific mutagenesis of herpes simplex virus (HSV-1) DNA fragments with high GC content. In this protocol, a PCR product was partially extended first using a cloned DNA fragment. The final mutagenized fragment was produced after a second extension using another PCR product and final amplification using external primers. The sequential use of two extension reduction increased the predicted frequency of the engineered mutation in the final product to 100%. This method was used to generate a mutated glycoprotein K (gK) gene specified by HSV-1. A recombinant virus that carried the mutated gK …

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Alu Fossil Relics - Distribution And Insertion Polymorphism, Santosh S. Arcot, Aaron W. Adamson, Jane E. Lamerdin, Brian Kanagy, Prescott L. Deininger, Anthony V. Carrano, Mark A. Batzer Jan 1996

Alu Fossil Relics - Distribution And Insertion Polymorphism, Santosh S. Arcot, Aaron W. Adamson, Jane E. Lamerdin, Brian Kanagy, Prescott L. Deininger, Anthony V. Carrano, Mark A. Batzer

Faculty Publications

Screening of a human genomic library with an oligonucleotide probe specific for one of the young subfamilies of Alu repeats (Ya5/8) resulted in the identification of several hundred positive clones. Thirty-three of these clones were analyzed in detail by DNA sequencing. Oligonucleotide primers complementary to the unique sequence regions flanking each Alu repeat were used in PCR-based assays to perform phylogenetic analyses, chromosomal localization, and insertion polymorphism analyses within different human population groups. All 33 Alu repeats were present only in humans and absent from orthologous positions in several nonhuman primate genomes. Seven Alu repeats were polymorphic for their presence/absence …

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Historical Diversification Of Birds In Northwestern South America: A Molecular Perspective On The Role Of Vicariant Events, Robb T. Brumfield, A. P. Capparella Jan 1996

Historical Diversification Of Birds In Northwestern South America: A Molecular Perspective On The Role Of Vicariant Events, Robb T. Brumfield, A. P. Capparella

Faculty Publications

Studies of South American biodiversity have identified several areas of endemism that may have enhanced historical diversification of South American organisms. Hypotheses concerning the derivation of birds in the Choco area of endemism in northwestern South America were evaluated using protein electrophoretic data from 14 taxonomically diverse species groups of birds. Nine of these groups demonstrated that the Choco area of endemism has a closer historical relationship to Central America than to Amazonia, a result that is consistent with phytogeographic evidence. Within species groups, genetic distances between cis-Andean (east of the Andes) and trans-Andean (west of the Andes) taxa are, …

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Pervanadate Activation Of Intracellular Kinases Leads To Tyrosine Phosphorylation And Shedding Of Syndecan-1, Jane Reiland, Vanessa L. Ott, Connie S. Lebakken, Charles Yeaman, James Mccarthy, Alan C. Rapraeger Jan 1996

Pervanadate Activation Of Intracellular Kinases Leads To Tyrosine Phosphorylation And Shedding Of Syndecan-1, Jane Reiland, Vanessa L. Ott, Connie S. Lebakken, Charles Yeaman, James Mccarthy, Alan C. Rapraeger

Faculty Publications

Syndecan-1 is a transmembrane haparan sulphate proteoglycan that binds extracellular matrices and growth factors, making it a candidate to act between these regulatory molecules and intracellular signalling pathways. It has a highly conserved transmembrane/cytoplasmic domain that contains four conserved tyrosines. One of these is in a consensus sequence for tyrosine kinase phosphorylation. As an initial step to investigating whether or not phosphorylation of these tyrosines is part of a signal-transduction pathway, we have monitored the tyrosine phosphorylation of syndecan-1 by cytoplasmic tyrosine kinases in intact cells. Tyrosine phosphorylation of syndecan-1 is observed when NMuMG cells are treated with sodium orthovanadate …

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A Low-Co2-Inducible Gene Encoding An Alanine:Α-Ketoglutarate Aminotransferase In Chlamydomonas Reinhardtii, Zhi Yuan Chen, Mark D. Burow, Catherine B. Mason, James V. Moroney Jan 1996

A Low-Co2-Inducible Gene Encoding An Alanine:Α-Ketoglutarate Aminotransferase In Chlamydomonas Reinhardtii, Zhi Yuan Chen, Mark D. Burow, Catherine B. Mason, James V. Moroney

Faculty Publications

At low-CO2 (air) conditions, the unicellular green alga Chlamydomonas reinhardtii acquires the ability to raise its internal inorganic carbon concentration. To study this adaptation to low CO2, cDNA clones induced under low-CO2 growth conditions were selected through differential screening. One full-length clone is 2552 bp, with an open reading frame encoding 521 amino acids. The deduced amino acid sequence shows about 50% identity with alanine:α-ketoglutarate aminotransferase (Ala AT, EC 2.6.1.2) from plants and animals, and the mRNA of this clone increased 4- to 5-fold 4 h after cells were switched from high-CO2 to low-CO2 growth conditions. The expression of the …

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Metabolism Of Gemmules From The Freshwater Sponge Eunapius Fragilis During Diapause And Post-Diapause States, Stephen H. Loomis, Steven C. Hand, Paul E. Fell Jan 1996

Metabolism Of Gemmules From The Freshwater Sponge Eunapius Fragilis During Diapause And Post-Diapause States, Stephen H. Loomis, Steven C. Hand, Paul E. Fell

Faculty Publications

Post-diapause gemmules of the freshwater sponge Eunapius fragilis remained quiescent when maintained at 5°C. Germination occurred within 48 to 72 h following warming to 20°-23°C, culminating with the emergence of a new sponge from the collagenous capsule. Both heat dissipation and oxygen consumption climbed steadily during germination and eventually reached 600% of the starting values. By comparison, energy flow was much lower over the same period of time in diapausing gemmules, clearly demonstrating metabolic depression during diapause. The calorimetric:respirometric (CR) ratio increased significantly from -354 kJ/mol O2 to -541 kJ/mol O2 between hours 3.5 and 56.5 of germination, with an …

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