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Selected Works

1998

Biology

Articles 1 - 10 of 10

Full-Text Articles in Life Sciences

Degradation Signal Masking By Heterodimerization Of Mata2 And Mata1 Blocks Their Mutual Destruction By The Ubiquitin-Proteasome Pathway, Rob Swanson, Phoebe R. Johnson, Larissa Rakhilina, Mark Hochstrasser Jul 1998

Degradation Signal Masking By Heterodimerization Of Mata2 And Mata1 Blocks Their Mutual Destruction By The Ubiquitin-Proteasome Pathway, Rob Swanson, Phoebe R. Johnson, Larissa Rakhilina, Mark Hochstrasser

Rob Swanson

Proteolysis by the ubiquitin-proteasome pathway is often regulated, but the mechanisms underlying such regulation remain ill-defined. In Saccharomyces cere-visiae, cell type is controlled by the MAT transcription factors. The a2repressor is a known ubiquitinpathway substrate in a haploid cells. We show that a1 is rapidly degraded in a haploids. In a/a diploids, a2 and a1 are stabilized by heterodimerization. Association depends on N-terminal coiled-coil interactions between a1 and a2. Residues in a2 important for these interactions overlap a critical determinant of an a2 degradation signal, which we delimit by extensive mutagenesis. Our data provide a detailed description of a natural …

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Untangling Confusion Between Eubranchipus Vernalis And Eubranchipus Neglectus (Branchiopoda : Anostraca), Denton Belk, Graziella Mura, Stephen C. Weeks Jan 1998

Untangling Confusion Between Eubranchipus Vernalis And Eubranchipus Neglectus (Branchiopoda : Anostraca), Denton Belk, Graziella Mura, Stephen C. Weeks

Stephen C. Weeks

Despite illustrations in Garman (1926) clearly showing the different antennal appendages of Eubranchipus vernalis and Eubranchipus neglectus, Creaser (1930) published erroneous drawings of the antennal appendages of these two species that led to more than 65 years of taxonomic confusion between them. We untangle this confusion, and show that these species have nonoverlapping areas of occurrence with E. vernalis to the east and E. neglectus to the west of the Appalachian Mountains. In addition, we present evidence supporting the use of resting-egg (cyst) morphology in studying evolutionary relationships among anostracan species. An important part of this usefulness is due to …

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Host-Plant Associations And Specificity Among Cynipid Gall-Inducing Wasps Of Eastern Usa, Warren Abrahamson, G. Melika, R, Scrafford, G. Csoka Dec 1997

Host-Plant Associations And Specificity Among Cynipid Gall-Inducing Wasps Of Eastern Usa, Warren Abrahamson, G. Melika, R, Scrafford, G. Csoka

Warren G. Abrahamson, II

No abstract provided.

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Root Growth, Developmental Changes In The Apex, And Hydraulic Conductivity For Opuntia Ficus-Indica During Drought, J. Dubrovsky, Gretchen North, P. Nobel Dec 1997

Root Growth, Developmental Changes In The Apex, And Hydraulic Conductivity For Opuntia Ficus-Indica During Drought, J. Dubrovsky, Gretchen North, P. Nobel

Gretchen North

Developmental changes in the root apex and accompanying changes in lateral root growth and root hydraulic conductivity were examined for Opuntia ficus-indica (L.) Miller during rapid drying, as occurs for roots near the soil surface, and more gradual drying, as occurs in deeper soil layers. During 7 d of rapid drying (in containers with a 3-cm depth of vermiculite), the rate of root growth decreased sharply and most root apices died; such a determinate pattern of root growth was not due to meristem exhaustion but rather to meristem mortality after 3 d of drying. The length of the meristem, the …

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Water Uptake And Structural Plasticity Along Roots Of A Desert Succulent During Prolonged Drought, Gretchen North, P. Nobel Dec 1997

Water Uptake And Structural Plasticity Along Roots Of A Desert Succulent During Prolonged Drought, Gretchen North, P. Nobel

Gretchen North

No abstract provided.

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Gall-Inducing Insects Provide Insights Into Plant Systematic Relationships, Warren Abrahamson, G. Melika, R. Scrafford, G. Csoka Dec 1997

Gall-Inducing Insects Provide Insights Into Plant Systematic Relationships, Warren Abrahamson, G. Melika, R. Scrafford, G. Csoka

Warren G. Abrahamson, II

No abstract provided.

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Just Lookin' For A Home, Warren G. Abrahamson Ii, A. E. Weis Dec 1997

Just Lookin' For A Home, Warren G. Abrahamson Ii, A. E. Weis

Warren G. Abrahamson, II

No abstract provided.

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Precocene Ii Modifies Maternal Responsiveness In The Burrower Bug, Sehirus Cinctus (Heteroptera)., Scott Kight Dec 1997

Precocene Ii Modifies Maternal Responsiveness In The Burrower Bug, Sehirus Cinctus (Heteroptera)., Scott Kight

Scott Kight

The anti‐Juvenile Hormone agent precocene II was used to investigate the relationship of corpora allata activity to subsocial behaviour in a burrower bug Sehirus cinctus Palisot (Heteroptera: Cydnidae). Egg‐brooding females treated with a range of dosages of precocene II exhibited reliably depressed maternal defensive behaviour when treated with at least 70 μg of precocene II, but attraction to eggs was only depressed at higher dosages. This effect was not due to precocene II toxicity, as demonstrated by the prevention of depression effects through simultaneous treatments of precocene II and the Juvenile Hormone analogue methoprene. Methoprene, however, failed to reinstate maternal …

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Revised Group Classification Of The Genus Spiroplasma, David L. Williamson, Robert F. Whitcomb, Joseph G. Tully, Gail E. Gasparich, David L. Rose, Patricia Carle, Joseph M. Bové, Kevin J. Hackett, Jean R. Adams, Roberta B. Henegar, Meghnad Konai, Claude Chastel, Frank E. French Dec 1997

Revised Group Classification Of The Genus Spiroplasma, David L. Williamson, Robert F. Whitcomb, Joseph G. Tully, Gail E. Gasparich, David L. Rose, Patricia Carle, Joseph M. Bové, Kevin J. Hackett, Jean R. Adams, Roberta B. Henegar, Meghnad Konai, Claude Chastel, Frank E. French

Gail Gasparich

Significant changes have been made in the systematics of the genus Spiroplasma (class Mollicutes) since it was expanded by revision in 1987 to include 23 groups and eight sub-groups. Since that time, two additional spiroplasmas have been assigned group numbers and species names. More recently, specific epithets have been assigned to nine previously designated groups and three sub-groups. Also, taxonomic descriptions and species names have been published for six previously ungrouped spiroplasmas. These six new organisms are: Spiroplasma alleghenense (strain PLHS-1T) (group XXVI), Spiroplasma lineolae (strain TALS-2T) (group XXVII), Spiroplasma platyhelix (strain PALS-1T) (group XXVIII), Spiroplasma montanense (strain HYOS-1T) (group …

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Serologic And Genomic Relatedness Of Group Xiv Spiroplasma Isolates From A Lampyrid Beetle And Tabanid Flies: An Ecologic Paradox, G. E. Gasparich, K. J. Hackett, F. E. French, R. F. Whitcomb Dec 1997

Serologic And Genomic Relatedness Of Group Xiv Spiroplasma Isolates From A Lampyrid Beetle And Tabanid Flies: An Ecologic Paradox, G. E. Gasparich, K. J. Hackett, F. E. French, R. F. Whitcomb

Gail Gasparich

Spiroplasma group XIV strain EC-1T and other isolates from the lampyrid beetle Ellychnia corrusca form a serogroup with tabanid spiroplasma strains (TC-1 and TS-1). It was hypothesized that similarities among these strains reflect a transmission cycle in which lampyrid beetles serve as overwintering hosts and tabanid adults become infected and transmit a homogeneous population of spiroplasma strains during spring, summer and autumn. In the present study, variations in restriction fragment length patterns suggest the presence of multiple genovars. Genotypic analysis may therefore be a companion to serology in elucidating spiroplasma diversity, and may provide clues to strain host range.

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