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Biology Faculty Publications

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Articles 1651 - 1680 of 1770

Full-Text Articles in Life Sciences

Connexin32 Is A Myelin-Related Protein In The Pns And Cns, Steven S. Scherer, Suzanne M. Deschênes, Yi-Tian Xu, Judith B. Grinspan, Kenneth H. Fischbeck, David L. Paul Dec 1995

Connexin32 Is A Myelin-Related Protein In The Pns And Cns, Steven S. Scherer, Suzanne M. Deschênes, Yi-Tian Xu, Judith B. Grinspan, Kenneth H. Fischbeck, David L. Paul

Biology Faculty Publications

We have examined the expression of a gap junction protein, connexin32 (Cx32), in Schwann cells and oligodendrocytes. In peripheral nerve, Cx32 is found in the paranodal myelin loops and Schmidt-Lanterman incisures of myelinating Schwann cells, and the levels of Cx32 protein and mRNA change in parallel with those of other myelin-related genes during development, Wallerian degeneration, and axonal regeneration. In the central nervous system, Cx32 is found in oligodendrocytes and their processes, but not in compact myelin, and the levels of Cx32 protein and mRNA increase during development in parallel with those of the other myelin genes. Thus, Cx32 is …

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The Vascular Flora Of The Potomac River Watershed Of King George County, Virginia, Mark P. Simmons, Donna M.E. Ware, W. John Hayden Sep 1995

The Vascular Flora Of The Potomac River Watershed Of King George County, Virginia, Mark P. Simmons, Donna M.E. Ware, W. John Hayden

Biology Faculty Publications

The results of two floristic studies of King George County, Virginia, are combined into an annotated checklist. Field work was initiated in 1983-84 with a study of Caledon Natural Area, a 2,500-acre tract with 3.5 miles of frontage on the Potomac River. Collecting resumed in 1991 and 1992 to include other portions of the county drained by the Potomac River. The study area contains a wide variety of habitats including dry upland woods, mesic ravines, low elevation river flats, beaches, swamps, marshes, and creeks; creeks and marshes include both brackish and freshwater environments. The Potomac River watershed of King George …

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Conservation Of Grassland Birds In The Northeast, Robert A. Askins Apr 1995

Conservation Of Grassland Birds In The Northeast, Robert A. Askins

Biology Faculty Publications

No abstract provided.

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Mistaken Identity?, W. John Hayden Apr 1995

Mistaken Identity?, W. John Hayden

Biology Faculty Publications

The December 1994 NEWS item "Red Menace" contains, I believe, an unfortunate misidentification of the algae allegedly responsible for the catastrophic mortality of sea birds from Pliocene deposits of the Florida Gulf Coast.

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Characterization Of A Saccharomyces Cerevisiae Strain Deleted For The Rad27 Gene; A Structural Homolog Of The Rad2 Nucleotide Excision Repair Gene, Michael S. Reagan, Wolfram Siede, Errol C. Friedberg Mar 1995

Characterization Of A Saccharomyces Cerevisiae Strain Deleted For The Rad27 Gene; A Structural Homolog Of The Rad2 Nucleotide Excision Repair Gene, Michael S. Reagan, Wolfram Siede, Errol C. Friedberg

Biology Faculty Publications

No abstract provided.

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Enhancer Trap Technique: A Novel Tool For Identification And Developmental Characterization Of Genes Of Drosophila, Amit Singh Mar 1995

Enhancer Trap Technique: A Novel Tool For Identification And Developmental Characterization Of Genes Of Drosophila, Amit Singh

Biology Faculty Publications

The classical technique of mutational screen for identification of genes controlling early development has now approached saturation. A new era in genetic identification and developmental characterization of genes in Drosophila has commenced with the advent of the enhancer trap technique. This technique involves mobilization of a P-lacZ vector to diverse chromosomal locations in the fruit fly genome to bring it under the regulation of developmentally expressed genes or their enhancer elements. The technique offers a strikingly elegant method of gaining entry into fruit fly genes.

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Isolation Of A Mouse Cdna Encoding Mtj1, A New Murine Member Of The Dnaj Family Of Proteins, Shannon E. Brightman, Gregory L. Blatch, Bruce R. Zetter Feb 1995

Isolation Of A Mouse Cdna Encoding Mtj1, A New Murine Member Of The Dnaj Family Of Proteins, Shannon E. Brightman, Gregory L. Blatch, Bruce R. Zetter

Biology Faculty Publications

We report the isolation and sequencing of MTJ1, a 1792-bp cDNA from an M27 murine lung carcinoma cell line. The largest ORF within MTJ1 encodes a 63,869-Da protein, containing a 73-amino-acid (aa) sequence (the J domain) that is conserved in proteins of the DnaJ family of chaperonins. The J domain of MTJ1 is bracketed by potential transmembrane domains in a similar configuration to the J domain of the yeast DnaJ-like protein, SEC63. Polyclonal antibodies raised against deduced aa sequences within MTJ1 recognized antigens of 62, 42 and 41 kDa that were enriched in the nuclear and heavy microsome subcellular fractions …

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Phylogenetic Reanalysis Of Strauch's Osteological Data Set For The Charadriiformes, Philip C. Chu Feb 1995

Phylogenetic Reanalysis Of Strauch's Osteological Data Set For The Charadriiformes, Philip C. Chu

Biology Faculty Publications

Strauch's (1978) compatibility analysis of relationships among the shorebirds (Charadriiformes) was the first study to examine the full range of charadriiform taxa in a reproducible way. Subsequently Mickevich and Parenti (1980) leveled serious charges against Strauch's characters, method of phylogenetic inference, and results. To account for these charges, Strauch's characters were re-examined and recoded, and parsimony analyses were performed on the revised matrix. A parsimony analysis on 74 taxa from the revised matrix yielded 855 shortest trees, each length = 286 and consistency index = 0.385. In each shortest tree there were two major lineages, a lineage of sandpiper-like birds …

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An Improved Method For Chemical Devitellinization Of X-Gal Stained Drosophila Embryos, Amit Singh, Madhuri Kango-Singh, P. Sinha Feb 1995

An Improved Method For Chemical Devitellinization Of X-Gal Stained Drosophila Embryos, Amit Singh, Madhuri Kango-Singh, P. Sinha

Biology Faculty Publications

In Drosophila developmental biological studies, X-gal staining is commonly employed to study the spatio-temporal expression of the lacZ reporter gene in the transformed flies or their embryos. Study of the lacZ pattern in embryos often suffers from the lack of an efficient and high yieldirrg technique for devitellinization of X-gal stained embryos. Devitellinization techniques employed during antibody staining, in situ hybridization or embryonic cuticular preparations generally do not give satisfactory results when used for similar purpose in X-gal stained embryos. This results in the flaky appearance of the blue stain. We present here an improved chemical devitellinization technique which gives …

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Increased Stem Cell Factor Release By Hemangioma-Derived Endothelial Cells, C. J. Meininger, Shannon Brightman, K. A. Kelly, B. R. Zetter Feb 1995

Increased Stem Cell Factor Release By Hemangioma-Derived Endothelial Cells, C. J. Meininger, Shannon Brightman, K. A. Kelly, B. R. Zetter

Biology Faculty Publications

Background: Capillary hemangiomas, the most common tumors in young children, consist of proliferating capillary vessels and endothelial cells. These tumors also contain large numbers of mast cells, compared with the normal surrounding skin or tissue. We have recently shown that stem cell factor (SCF), the gene product of the murine steel locus, can act as a chemoattractant for mast cells. In this study, we investigated whether SCF might be involved in the recruitment and maintenance of mast cells in hemangiomas. Experimental Design: Cultured endothelial cells derived from a murine hemangioma were compared with normal vascular endothelial cells for the ability …

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Complementary Gradients In Expression And Binding Of Elf-1 And Mek4 In Development Of The Topographic Retinotectal Projection Map, Masaru Nakamoto Jan 1995

Complementary Gradients In Expression And Binding Of Elf-1 And Mek4 In Development Of The Topographic Retinotectal Projection Map, Masaru Nakamoto

Biology Faculty Publications

Topographic maps with a defined spatial ordering of neuronal connections are a key feature of brain organization. Such maps are believed to develop in response to complementary position-specific labels in presynaptic and postsynaptic fields. However, the complementary labeling molecules are not known. In the well studied visual map of retinal axons projecting to the tectum, the labels are hypothesized to be in gradients, without needing large numbers of cell-specific molecules. We recently cloned ELF-1 as a ligand for Eph family receptors. Here, RNA hybridization shows matching expression gradients for ELF-1 in the tectum and its receptor Mek4 in the retina. …

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Characterization Of A Mutant Strain Of Saccharomyces Cerevisiae With A Deletion Of The Rad27 Gene, A Structural Homolog Of The Rad2 Nucleotide Excision Repair Gene, Michael S. Reagan, Christopher Pittenger, Wolfram Siede, Errol C. Friedberg Jan 1995

Characterization Of A Mutant Strain Of Saccharomyces Cerevisiae With A Deletion Of The Rad27 Gene, A Structural Homolog Of The Rad2 Nucleotide Excision Repair Gene, Michael S. Reagan, Christopher Pittenger, Wolfram Siede, Errol C. Friedberg

Biology Faculty Publications

We have constructed a strain of Saccharomyces cerevisiae with a deletion of the YKL510 open reading frame, which was initially identified in chromosome XI as a homolog of the RAD2 nucleotide excision repair gene (A. Jacquier, P. Legrain, and B. Dujon, Yeast 8:121–132, 1992). The mutant strain exhibits increased sensitivity to UV light and to the alkylating agent methylmethane sulfonate but not to ionizing radiation. We have renamed the YKL510 open reading frame the RAD27 gene, in keeping with the accepted nomenclature for radiationsensitive yeast mutants. Epistasis analysis indicates that the gene is in the RAD6 group of genes, which …

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A Preliminary Catalog Of The Lichen-Forming Fungi Of Nebraska, Robert S. Egan, Richard C. Witt, Yolanda E. Peck, John P. Goeden, Teresa L. Cherney Jan 1995

A Preliminary Catalog Of The Lichen-Forming Fungi Of Nebraska, Robert S. Egan, Richard C. Witt, Yolanda E. Peck, John P. Goeden, Teresa L. Cherney

Biology Faculty Publications

A total of 438 lichen-forming taxa have been reported in the literature from Nebraska. Based on current taxonomic concepts and synonymy we recognized 312 lichen species in this catalog for the state. Published reports oflichen species citing specific collection localities are listed from only 31 counties. These records are concentrated in eastern Nebraska with the largest numbers of species listed from localities in Cass, Lancaster, Saunders, Richardson, and Sarpy counties

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Hyla Albopunctata, Rafael O. De Sá Jan 1995

Hyla Albopunctata, Rafael O. De Sá

Biology Faculty Publications

Hyla albopunctata is a medium-sized species in the albopunctata group, adults range in size from 42-52 mm SVL (males average 47 mm and females 49 mm). The head is triangular in outline, always longer than wide. The snout is moderately long and acuminate in dorsal view, whereas in lateral view, it is acuminate and protrudes beyond the mandible to form an angle of 45 degrees over the mandible. The canthus rostralis is rounded and distinct, the loreal region is slightly concave, and the internarial region is slightly convex. The eyes are large, approximately twice the diameter of the tympanum. The …

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Mechanisms For Soil Moisture Effects On Activity Of Nitrifying Bacteria, John M. Stark, M. K. Firestone Jan 1995

Mechanisms For Soil Moisture Effects On Activity Of Nitrifying Bacteria, John M. Stark, M. K. Firestone

Biology Faculty Publications

Moisture may limit microbial activity in a wide range of environments including salt water, food, wood, biofilms, and soils. Low water availability can inhibit microbial activity by lowering intracellular water potential and thus reducing hydration and activity of enzymes. In solid matrices, low water content may also reduce microbial activity by restricting substrate supply. As pores within solid matrices drain and water films coating surfaces become thinner, diffusion path lengths become more tortuous, and the rate of substrate diffusion to microbial cells declines. We used two independent techniques to evaluate the relative importance of cytoplasmic dehydration versus diffusional limitations in …

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Daughter Cells Of Saccharomyces Cerevisiae From Old Mothers Display A Reduced Life Span, Nicanor Austriaco, Brian K. Kennedy, Leonard Guarente Dec 1994

Daughter Cells Of Saccharomyces Cerevisiae From Old Mothers Display A Reduced Life Span, Nicanor Austriaco, Brian K. Kennedy, Leonard Guarente

Biology Faculty Publications

The yeast Saccharomyces cerevisiae typically divides asymmetrically to give a large mother cell and a smaller daughter cell. As mother cells become old, they enlarge and produce daughter cells that are larger than daughters derived from young mother cells. We found that occasional daughter cells were indistinguishable in size from their mothers, giving rise to a symmetric division. The frequency of symmetric divisions became greater as mother cells aged and reached a maximum occurrence of 30% in mothers undergoing their last cell division. Symmetric divisions occurred similarly in rad9 and ste12 mutants. Strikingly, daughters from old mothers, whether they arose …

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Second Intermediate Host-Specificity Of Haematoloechus Complexus And Haematoloechus Medioplexus (Digenea: Haematoloechidae), Scott D. Snyder, John J. Janovy Dec 1994

Second Intermediate Host-Specificity Of Haematoloechus Complexus And Haematoloechus Medioplexus (Digenea: Haematoloechidae), Scott D. Snyder, John J. Janovy

Biology Faculty Publications

Second intermediate host-specificity was examined for two species of the frog lung fluke genus Haematoloechus. Nine species of freshwater arthropods were exposed to cercariae of H. complexus and H. medioplexus. Metacercariae of H. complexus developed in all arthropod species used. Metacercariae of H. medioplexus developed only in anisopteran odonate naiads. This difference in host utilization may have epizootiological implications. The potential development of H. complexus in a greater number of arthropods than H. medioplexus may increase the chances of ingestion of H. complexus by an anuran host. The range of arthropods parasitized by H. complexus indicates that host-specificity …

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Open Corridors In A Heavily Forested Landscape: Impact On Shrubland And Forest-Interior Birds, Robert A. Askins Jul 1994

Open Corridors In A Heavily Forested Landscape: Impact On Shrubland And Forest-Interior Birds, Robert A. Askins

Biology Faculty Publications

In eastern North America, remnant patches of forest surrounded by open habitat constitute unfavorable habitat for many species of migratory forest birds because of high rates of nest predation and cowbird parasitism. Although most evidence for this relationship comes from 'forest islands' surrounded by residential or agricultural land, even forest patches isolated from other forests by narrow open corridors such as roads and powerline rights-of-way seem to show this pattern. Productive habitat for migratory birds can be maintained by consolidating corridors and routing them along the periphery of forests to retain as much continuous forest as possible. Consolidation of open …

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Mutations In The Non-Helical Linker Segment L1-2 Of Keratin 5 In Patients With Weber-Cockayne Epidermolysis Bullosa Simplex, Yiu-Mo Chan, Qian-Chun Yu, Janine M. Leblanc-Straceski, Angela Christiano, Lena Pulkkinen, Raju S. Kucherlapati, Jouni Uitto, Elaine Fuchs Apr 1994

Mutations In The Non-Helical Linker Segment L1-2 Of Keratin 5 In Patients With Weber-Cockayne Epidermolysis Bullosa Simplex, Yiu-Mo Chan, Qian-Chun Yu, Janine M. Leblanc-Straceski, Angela Christiano, Lena Pulkkinen, Raju S. Kucherlapati, Jouni Uitto, Elaine Fuchs

Biology Faculty Publications

Keratins are the major structural proteins of the epidermis. Analyzing keratin gene sequences, appreciating the switch in keratin gene expression that takes place as epidermal cells commit to terminally differentiate, and elucidating how keratins assemble into 10 nm filaments, have provided the foundation that has led to the discoveries of the genetic bases of two major classes of human skin diseases, epidermolysis bullosa simplex (EBS) and epidermolytic hyperkeratosis (EH). These diseases involve point mutations in either the basal epidermal keratin pair, K5 and K14 (EBS), or the suprabasal pair, K1 and K10 (EH). In severe cases of EBS and EH, …

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Phylogenetic Analysis Of Segment 10 From African Horsesickness Virus And Cognate Genes From Other Orbiviruses, Rafael O. De Sá, Marla Zellner, Marvin J. Grubman Mar 1994

Phylogenetic Analysis Of Segment 10 From African Horsesickness Virus And Cognate Genes From Other Orbiviruses, Rafael O. De Sá, Marla Zellner, Marvin J. Grubman

Biology Faculty Publications

Utilizing the reverse transcriptase-polymerase chain reaction (RT-PCR) procedure, we have synthesized full-length copies of segment 10 from African horsesickness virus (AHSV) serotypes 1,4 and 8. The genes were cloned, sequenced and compared with the sequence of the cognate gene from AHSV serotypes 3 and 9. Sequences were analyzed to assess evolutionary relationships among serotypes using cladistics. Based on this analysis the data support a close relationship between serotypes 4 and 9 and between serotypes 1 and 8 and a closer relationship of serotype 3 to the 4 and 9 group.

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Terrapene Carolina Carolina, Joseph C. Mitchell, Rafael O. De Sá Jan 1994

Terrapene Carolina Carolina, Joseph C. Mitchell, Rafael O. De Sá

Biology Faculty Publications

TERRAPENE CAROLINA CAROLINA (Eastern Box Turtle). REPRODUCTION. Female Terrapene carolina containing oviductal eggs have been recorded in Virginia from 26 May to 25 July (Mitchell, in press. The Reptiles of Virginia. Smithsonian Inst. Press, Washington, D.C.). Other reports of reproduction in Terrapene (see list in Ernst and McBreen 1991. Cat. Amer. Amphib. Rept. 512.1-512.13) indicate that nesting occurs in late spring and early summer throughout its range.

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What Are Squirrels Hiding, Michael Steele, Peter D. Smallwood Jan 1994

What Are Squirrels Hiding, Michael Steele, Peter D. Smallwood

Biology Faculty Publications

The half-eaten acorns of squirrels are clues to their complex relationship with oaks. The special relationship between squirrels and acorns is examined.

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Systematic Anatomy Of Euphorbiaceae Subfamily Oldfieldioideae I. Overview, W. John Hayden Jan 1994

Systematic Anatomy Of Euphorbiaceae Subfamily Oldfieldioideae I. Overview, W. John Hayden

Biology Faculty Publications

The biovulate subfamily Oldfieldioideae of Euphorbiaceae, characterized by spiny pollen, is an otherwise apparently diverse assemblage of mostly Southern Hemisphere trees and shrubs that traditionally have been allied with genera of Phyllanthoideae and Porantheroideae sensu Pax and Hoffmann. Although fairly diverse anatomically, the following structures characterize the subfamily with only a few exceptions: pinnate brochidodromous venation with generally randomly organized tertiary and higher order venation; foliar and petiolar glands absent; unicellular or unbranched uniseriate trichomes; latex absent; mucilaginous epidermis or hypodermis; brachyparacytic stomata; vessel elements with simple perforation plates and alternate, often very small, intervascular pits; thick-walled nonseptate imperforate tracheary …

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Nectar-Seeking Visits By Butterflies In A Tallgrass Prairie Remnant In Eastern Nebraska, Tanya Bray Jan 1994

Nectar-Seeking Visits By Butterflies In A Tallgrass Prairie Remnant In Eastern Nebraska, Tanya Bray

Biology Faculty Publications

Stolley Prairie, a tallgrass virgin prairie remnant in eastern Nebraska, was visited 20 times between May 25 and August 14, 1988. Fifty-two species offorbs were observed in bloom during this period. Twenty-seven species of butterflies were observed and 21 species made 262 nectar-seeking visits to 21 plant species. While numbers offorbs in bloom did not strongly correlate with numbers of butterflies present, peaks of butterfly occurrence appeared to follow peaks of blossom abundance. The number of plant species utilized by a species of butterfly ranged from one to nine. Plants with an abundance of nectar such as common milkweed and …

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Energy Conservation By Formation Swimming - Metabolic Evidence From Ducklings, Frank E. Fish Jan 1994

Energy Conservation By Formation Swimming - Metabolic Evidence From Ducklings, Frank E. Fish

Biology Faculty Publications

No abstract provided.

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Development And Application Of A Thermistor Current Meter, Carl M. Way, Albert J. Burky, Christine Miller-Way Jan 1994

Development And Application Of A Thermistor Current Meter, Carl M. Way, Albert J. Burky, Christine Miller-Way

Biology Faculty Publications

This report provides details for the construction of a hot-bead thermistor current meter which is capable of measuring water velocities on a millimeter spatial scale and for the construction of a compact and accurate calibration system. Hot-bead thermistor current meters can be built with response times of 200 ms capable of measuring velocities between 0.1 and 80 cm s-1. The construction of a sturdy probe for application in lotic systems such as high gradient Hawaiian streams was achieved by the use of heavy-duty acrylic tubing, small stainless steel gas-chromatography tubing, and flexible Tygon spaghetti tubing. An acrylic handle anchors the …

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Stem Development, Medullary Bundles, And Wood Anatomy Of Croton Glandulosus Var. Septentrionalis (Euphorbiaceae), Sheila M. Hayden, W. John Hayden Jan 1994

Stem Development, Medullary Bundles, And Wood Anatomy Of Croton Glandulosus Var. Septentrionalis (Euphorbiaceae), Sheila M. Hayden, W. John Hayden

Biology Faculty Publications

Anatomy and development of vascular tissues in the annual stems of Croton glandulosus var. septentrionalis are described. In primary stages of growth the stem possesses a eustele of bicollateral bundles; international phloem is notably more extensive than the external. In addition to a vascular cambium and secondary xylem that form in the usual fashion, additional cambia add cells to the internal phloem portion of the bicollateral bundles, forming well-marked medullary bundles at the perimeter of the pith. At first, the perimedullary cambial strands produce only internal secondary phloem; later, internal secondary xylem is present, the medullary bundles have an inverted …

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Considerations For Evaluating Ultraviolet Radiation-Induced Genetic Damage Relative To Antarctic Ozone Depletion, Deneb Karentz Jan 1994

Considerations For Evaluating Ultraviolet Radiation-Induced Genetic Damage Relative To Antarctic Ozone Depletion, Deneb Karentz

Biology Faculty Publications

Springtime ozone depletion over the Antarctic results in increased UVB in local marine environments. It has been established that decreases in primary productivity occur with decreases in ozone concentrations, but the impact of increased UVB on the functioning and stability of the ecosystem has not yet been determined. Very little has been done to evaluate the potential for genetic damage caused by the increase in UVB, and this type of damage is most significant relative to the fitness and maintenance of populations. An essential problem in evaluating genotoxic effects is the lack of appropriate techniques to sample and quantify genetic …

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Xenopus Laevis As A Model Organism, David C. Cannatella, Rafael O. De Sá Dec 1993

Xenopus Laevis As A Model Organism, David C. Cannatella, Rafael O. De Sá

Biology Faculty Publications

Model organisms are often assumed to be representative of some more inclusive taxon of which the species is a part. This assumption leads to mistaken generalizations about the evolutionary and comparative significance of the data gathered. This paper reviews com? parative and evolutionary studies of Xenopus laevis and its relatives. Phylogenetic analysis of data from DNA sequences and morphology indicate that Xenopus is monophyletic and that Silurana is its sister group. The most basal lineages of Pipidae diverged prior to the breakup of Gondwana. The bizarre morphology of Xenopus is in part due to changes in the mode of meta? …

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Bone As A Spring, Frank E. Fish Nov 1993

Bone As A Spring, Frank E. Fish

Biology Faculty Publications

No abstract provided.

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