Life Sciences Commons^™

Rapid Senescence In Pacific Salmon, Yolanda E. Morbey, Chad Brassil, Andrew P. Hendry

School of Biological Sciences: Faculty Publications

Any useful evolutionary theory of senescence must be able to explain variation within and among natural populations and species. This requires a careful characterization of age-specific mortality rates in nature as well as the intrinsic and extrinsic factors that influence these rates. We perform this task for two populations of semelparous Pacific salmon. During the breeding season, estimated daily mortality rates increased from 0 to 0.2–0.5 (depending on the year) over the course of several weeks. Early-arriving individuals had a later onset and/or a lower rate of senescence in each breeding season, consistent with adaptive expectations based on temporal variation …

Characterization Of Different Crystal Forms Of The Α-Glucosidase Mala From Sulfolobus Solfataricus, Heidi Asschenfeldt Ernst, Martin Willemoës, Leila Lo Leggio, Gordon Leonard, Paul H. Blum, Sine Larsen

School of Biological Sciences: Faculty Publications

MalA is an _-glucosidase from the hyperthermophilic archaeon Sulfolobus

solfataricus. It belongs to glycoside hydrolase family 31, which includes several

medically interesting α-glucosidases. MalA and its selenomethionine derivative

have been overproduced in Escherichia coli and crystallized in four different

crystal forms. Microseeding was essential for the formation of good-quality

crystals of forms 2 and 4. For three of the crystal forms (2, 3 and 4) full data sets

could be collected. The most suitable crystals for structure determination are the

monoclinic form 4 crystals, belonging to space group P21, from which data sets

extending to 2.5 Å resolution …

Between-Group Transmission Dynamics Of The Swallow Bug, Oeciacus Vicarius, Charles R. Brown, Mary Bomberger Brown

School of Biological Sciences: Faculty Publications

The parasitic cimicid swallow bug, Oeciacus vicarius, is the principal invertebrate vector for Buggy Creek virus (BCRV) and has also been associated with Venezuelan equine encephalitis virus. To help understand the spread of this vector, we experimentally measured the transmission of O. vicarius between groups (colonies) of its main host, the cliff swallow (Petrochelidon pyrrhonota), in the field. Transmission of bugs between colonies varied significantly with year, size of the colony, and week within the season. Bug immigration into sites tended to peak in mid-summer. Swallow nests in larger colonies had more consistent rates of bug introduction than …

Testosterone And Group Size In Cliff Swallows: Testing The “Challenge Hypothesis” In A Colonial Bird, Linda C. Smith, Samrrah A. Raouf, Mary Bomberger Brown, John C. Wingfield, Charles R. Brown

School of Biological Sciences: Faculty Publications

The “challenge hypothesis” states that increases in testosterone levels of male animals during the breeding season are directly related to the extent of intrasexual competition for resources or mates that they experience. Although often tested in territorial species, the challenge hypothesis has not been evaluated for colonial animals that live in groups of different sizes and that thus experience different intensities of intrasexual competition. We measured circulating testosterone levels of male and female cliff swallows (Petrochelidon pyrrhonota) in southwestern Nebraska, where these birds nest in colonies of widely different sizes. Males had significantly higher testosterone levels than females, …

Gene Set Coregulated By The Saccharomyces Cerevisiae Nonsense-Mediated Mrna Decay Pathway, Rachel Taylor, Bessie Wanja Kebaara, Tara Nazarenus, Ashley Jones, Rena Yamanaka, Rachel Uhrenholdt, Jason P. Wendler, Audrey L. Atkin

School of Biological Sciences: Faculty Publications

The nonsense-mediated mRNA decay (NMD) pathway has historically been thought of as an RNA surveillance system that degrades mRNAs with premature translation termination codons, but the NMD pathway of Saccharomyces cerevisiae has a second role regulating the decay of some wild-type mRNAs. In S. cerevisiae, a significant number of wild-type mRNAs are affected when NMD is inactivated. These mRNAs are either wild-type NMD substrates or mRNAs whose abundance increases as an indirect consequence of NMD. A current challenge is to sort the mRNAs that accumulate when NMD is inactivated into direct and indirect targets. We have developed a …

Upf1p, A Highly Conserved Protein Required For Nonsense-Mediated Mrna Decay, Interacts With The Nuclear Pore Proteins Nup100p And Nup116p, Tara Nazarenus, Rebecca Cedarberg, Ryan Bell, Joseph Cheatle, Amanda Forch, Alexis Haifley, Ann Hou, Bessie Wanja Kebaara, Christina Shields, Kate Stoysich, Rachel Taylor, Audrey L. Atkin

School of Biological Sciences: Faculty Publications

Saccharomyces cerevisiae Upf1p is a 971-amino-acid protein that is required for the nonsense-mediated mRNA decay (NMD) pathway, a pathway that degrades mRNAs with premature translational termination codons. We have identified a two-hybrid interaction between Upf1p and the nuclear pore (Nup) proteins, Nup100p and Nup116p. Both nucleoporins predominantly localize to the cytoplasmic side of the nuclear pore and participate in mRNA transport. The two-hybrid interaction between Upf1p and the nuclear pore proteins, Nup100p and Nup116p, is dependent on the presence of the C-terminal 158 amino acids of Upf1p. Nup100p and Nup116p can be coimmunoprecipitated from whole-cell extracts with Upf1p, confirming in …

Effects Of Endogenous Steroid Hormone Levels On Annual Survival In Cliff Swallows, Charles R. Brown, Mary Bomberger Brown, Samrrah A. Raouf, Linda C. Smith, John C. Wingfield

School of Biological Sciences: Faculty Publications

The hormone corticosterone is an important part of animals’ response to environmental stress, modulating short-term adaptive changes in behavior and physiology. The hormone testosterone is also critical, especially for males, in regulating the expression of sexual behavior and parental care. These hormones can have costly consequences, however, and within populations individuals show variation in endogenous levels of both corticosterone and testosterone. We studied how annual survival varied as a function of natural levels of these hormones in colonially breeding Cliff swallows (Petrochelidon pyrrhonota) in southwestern Nebraska, USA, in 2000–2003. We sampled hormone levels of birds caught at colonies …