Life Sciences Commons^™

Crystal Structure Of The Sars Protein From Staphylococcus Aureus, Ronggui Li, Adhar C. Manna, Shaodong Dai, Ambrose L. Cheung, Gongyi Zhang

Dartmouth Scholarship

The expression of virulence determinants in Staphylococcus aureus is controlled by global regulatory loci (e.g., sarA and agr). One of these determinants, protein A (spa), is activated by sarS, which encodes a 250-residue DNA-binding protein. Genetic analysis indicated that the agr locus likely mediates spa repression by suppressing the transcription of sarS. Contrary to SarA and SarR, which require homodimer formation for proper function, SarS is unusual within the SarA protein family in that it contains two homologous halves, with each half sharing sequence similarity to SarA and SarR. Here we report the 2.2 Å …

Is Hp1 An Rna Detector That Functions Both In Repression And Activation?, Rebecca Kellum

Biology Faculty Publications

Heterochromatin is defined as regions of compact chromatin that persist throughout the cell cycle (Heitz, 1928). The earliest cytological observations of heterochromatin were followed by ribonucleotide labeling experiments that showed it to be transcriptionally inert relative to the more typical euchromatic regions that decondense during interphase. Genetic studies of rearrangements that place euchromatic genes next to blocks of heterochromatin also pointed out the repressive nature of heterochromatin (Grigliatti, 1991; and references therein). The discovery of the heterochromatin-enriched protein heterochromatin protein 1 (HP1) by Elgin and co-workers in the mid-1980s suggested that the distinct cytological features of this chromatin may be …

Genomic And Proteomic Profiling Of Responses To Toxic Metals In Human Lung Cells, Angeline S. Andrew, Amy J. Warren, Aaron Barchowsky, Kaili A. Temple, Linda Klei, Nicole V. Soucy, Kimberly A. O'Hara, Joshua W. Hamilton

Dartmouth Scholarship

Examining global effects of toxic metals on gene expression can be useful for elucidating patterns of biological response, discovering underlying mechanisms of toxicity, and identifying candidate metal-specific genetic markers of exposure and response. Using a 1,200 gene nylon array, we examined changes in gene expression following low-dose, acute exposures of cadmium, chromium, arsenic, nickel, or mitomycin C (MMC) in BEAS-2B human bronchial epithelial cells. Total RNA was isolated from cells exposed to 3 M Cd(II) (as cadmium chloride), 10 M Cr(VI) (as sodium dichromate), 3 g/cm2 Ni(II) (as nickel subsulfide), 5 M or 50 M As(III) (as sodium arsenite), or …

Minus-End Capture Of Preformed Kinetochore Fibers Contributes To Spindle Morphogenesis, Alexey Khodjakov, Lily Copenagle, Michael B. Gordon, Duane A. Compton, Tarun M. Kapoor

Dartmouth Scholarship

Near-simultaneous three-dimensional fluorescence/differential interference contrast microscopy was used to follow the behavior of microtubules and chromosomes in living alpha-tubulin/GFP-expressing cells after inhibition of the mitotic kinesin Eg5 with monastrol. Kinetochore fibers (K-fibers) were frequently observed forming in association with chromosomes both during monastrol treatment and after monastrol removal. Surprisingly, these K-fibers were oriented away from, and not directly connected to, centrosomes and incorporated into the spindle by the sliding of their distal ends toward centrosomes via a NuMA-dependent mechanism. Similar preformed K-fibers were also observed during spindle formation in untreated cells. In addition, upon monastrol removal, centrosomes established a transient …

G03-1513 Understanding Fungal (Mold) Toxins (Mycotoxins), Michael P. Carlson, Steveb M. Ensley

University of Nebraska-Lincoln Extension: Historical Materials

Mycotoxins are chemicals produced by fungi (molds) under certain conditions. They are not essential for fungal growth or reproduction, and are toxic to animals or humans.

This NebGuide briefly discusses mycotoxins commonly encountered in grains and feeds used in Nebraska and the mycotoxicoses they cause. Mycotoxin sources and clinical signs, lesions, diagnostic aids and treatment for each mycotoxicosis are listed.

G03-1515 Sampling And Analyzing Feed For Fungal (Mold) Toxins (Mycotoxins), Michael P. Carlson, Steven M. Ensley

University of Nebraska-Lincoln Extension: Historical Materials

Mycotoxins are chemicals produced by fungi (molds) under certain conditions. They are not essential for fungal growth or reproduction, and are toxic to animals or humans. They are naturally present in feed and cannot always be avoided.

The purposes of this NebGuide are to provide information about sampling feeds to detect the presence of mycotoxins in them and about how feeds may be analyzed for mycotoxins.

G03-1514 Use Of Feed Contaminated With Fungal (Mold) Toxins (Mycotoxins), Michael P. Carlson, Steve M. Ensley

University of Nebraska-Lincoln Extension: Historical Materials

Mycotoxins are chemicals produced by fungi (molds) under certain conditions. They are not essential for fungal growth or reproduction, and they are toxic to animals or humans. They are naturally occurring chemicals found in grains, food and feed consumed by humans and animals and cannot be completely avoided. Accordingly, we try to control the amount of such chemicals ingested by humans and animals.

The purpose of this NebGuide is to provide guidelines on use of mycotoxin-contaminated feeds.

Nf03-571 Aspergillus Flavus And Aflatoxins In Corn, Jim Stack, Michael Carlson

University of Nebraska-Lincoln Extension: Historical Materials

The severe weather conditions of the 2002 growing season resulted in an increase in the incidence and severity of aflatoxin contamination of both food grade and feed grade corn in Nebraska.

The mycotoxin called aflatoxin is produced by the grain mold Aspergillus flavus. Not all isolates of A. flavus produced aflatoxin and isolates that are capable of producing aflatoxin do not always synthesize the toxin. Many factors including environmental conditions and host suscepbitility, determine the incidence and severity of grain mold and subsequent mycotoxin contamination.

This NebFact discusses the cause and occurrence of aflatoxin in corn; the effects it has …

Nf03-570 Fumonisins In Corn, Jim Stack, Michael Carlson

University of Nebraska-Lincoln Extension: Historical Materials

During the past two years, millers have rejected some Nebraska food grade corn because it was contaminated with the mycotoxin fumonisin. Most of the contaminated samples and the highest levels of contamination were detected in corn from counties in the eastern half of Nebraska.

Fumonisins are mycotoxins produced by the grain molds Fusarium verticillioides and Fusarium proliferatum. These fungi are commonly found in corn throughout the United States.

This NebFact discusses the cause and occurrence of fumonisin in corn; the effects it has on plants, animals and humans; and management options to minimize fumonisin contamination.

G03-1485 Guidelines For The Prudent Use Of Antibiotics In Food Animals, Katherine Irwin, David R. Smith, Grasso M. Ebako, Steve Ensley, Dicky D. Griffin, Arden Wohlers

University of Nebraska-Lincoln Extension: Historical Materials

This NebGuide explains why antibiotics must be used with care and how to prudently use antibiotics to treat food animals.

Antibiotics are used to improve animal health and productivity. You, the animal caregiver, make important decisions about how antibiotics are finally used in food producing animals. Antibiotics should be used prudently to ensure they are effective, do not leave residues in food, and will continue to benefit man and animals in the future. Are you prepared to make the best decisions about using antibiotics in animals?