Life Sciences Commons^™

Cattle Grazing On A Hillside

Farming in Arkansas

Image of a herd of cattle grazing on a hillside on a sunny day.

The Stromal Cell-Derived Factor-1alpha/Cxcr4 Ligand-Receptor Axis Is Critical For Progenitor Survival And Migration In The Pancreas., Ayse G. Kayali, Kurt Van Gunst, Iain L. Campbell, Aleksandr Stotland, Marcie Kritzik, Guoxun Liu, Malin Flodström-Tullberg, You-Qing Zhang, Nora Sarvetnick

Journal Articles: Regenerative Medicine

The SDF-1alpha/CXCR4 ligand/chemokine receptor pair is required for appropriate patterning during ontogeny and stimulates the growth and differentiation of critical cell types. Here, we demonstrate SDF-1alpha and CXCR4 expression in fetal pancreas. We have found that SDF-1alpha and its receptor CXCR4 are expressed in islets, also CXCR4 is expressed in and around the proliferating duct epithelium of the regenerating pancreas of the interferon (IFN) gamma-nonobese diabetic mouse. We show that SDF-1alpha stimulates the phosphorylation of Akt, mitogen-activated protein kinase, and Src in pancreatic duct cells. Furthermore, migration assays indicate a stimulatory effect of SDF-1alpha on ductal cell migration. Importantly, blocking …

Il-23 Produced By Cns-Resident Cells Controls T Cell Encephalitogenicity During The Effector Phase Of Experimental Autoimmune Encephalomyelitis, Burkhard Becher, Brigit G. Durell, Randolph J. Noelle

Dartmouth Scholarship

CNS-resident cells, in particular microglia and macrophages, are a source of inflammatory cytokines during inflammation within the CNS. Expression of IL-23, a recently discovered cytokine, has been shown to be critical for the development of experimental autoimmune encephalomyelitis (EAE) in mice. Expression of the p40 subunit of IL-12 and IL-23 by microglia has been shown in situ and in vitro, but direct evidence for a functional significance of p40 expression by CNS cells during an immune response in vivo is still lacking. Here we report that p40 plays a critical role in maintaining encephalitogenicity during the disease course. By using …

Salicylic Acid Attenuates Virulence In Endovascular Infections By Targeting Global Regulatory Pathways In Staphylococcus Aureus, Leon Iri Kupferwasser, Michael R. Yeaman, Cynthia C. Nast, Deborah Kupferwasser, Yan-Qiong Xiong, Marco Palma, Ambrose L. Cheung, Arnold S. Bayer

Dartmouth Scholarship

Aspirin has been previously shown to reduce the in vivo virulence of Staphylococcus aureus in experimental endocarditis, through antiplatelet and antimicrobial mechanisms. In the present study, salicylic acid, the major in vivo metabolite of aspirin, mitigated two important virulence phenotypes in both clinical and laboratory S. aureus strains: α-hemolysin secretion and fibronectin binding in vitro. In addition, salicylic acid reduced the expression of the α-hemolysin gene promoter, hla, and the fibronectin gene promoter, fnbA. Transcriptional analysis, fluorometry, and flow cytometry revealed evidence of salicylic acid–mediated activation of the stress-response gene sigB. Expression of the sigB-repressible global …

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 …

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 …

Asymmetry Of The Central Apparatus Defines The Location Of Active Microtubule Sliding In Chlamydomonas Flagella, Matthew J. Wargo, Elizabeth F. Smith

Dartmouth Scholarship

Regulation of ciliary and flagellar motility requires spatial control of dynein-driven microtubule sliding. However, the mechanism for regulating the location and symmetry of dynein activity is not understood. One hypothesis is that the asymmetrically organized central apparatus, through interactions with the radial spokes, transmits a signal to regulate dynein-driven microtubule sliding between subsets of doublet microtubules. Based on this model, we hypothesized that the orientation of the central apparatus defines positions of active microtubule sliding required to control bending in the axoneme. To test this, we induced microtubule sliding in axonemes isolated from wild-type and mutant Chlamydomonas cells, and then …

Manganese Distribution Across The Blood-Brain Barrier. I. Evidence For Carrier-Mediated Influx Of Managanese Citrate As Well As Manganese And Manganese Transferrin, Janelle S. Crossgrove, David D. Allen, Bonny L. Bukaveckas, Susan S. Rhineheimer, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Manganese (Mn) is an essential element and a neurotoxicant. Regulation of Mn movement across the blood–brain barrier (BBB) contributes to whether the brain Mn concentration is functional or toxic. In plasma, Mn associates with water, small molecular weight ligands and proteins. Mn speciation may influence the kinetics of its movement through the BBB. In the present work, the brain influx rates of ⁵⁴Mn²⁺, ⁵⁴Mn citrate and ⁵⁴Mn transferrin (⁵⁴Mn Tf) were determined using the in situ brain perfusion technique. The influx rates were compared to their predicted diffusion rates, which were determined from …

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.

G03-1527 Annual Forages For The Nebraska Panhandle, Burt A. Weichenthal, David D. Baltensperger, K. P. Vogel, S. D. Masterson, J.M. Blumenthal, J.M. Krall

University of Nebraska-Lincoln Extension: Historical Materials

Annual forages have value as pasture, green chop, silage, and hay. With adequate soil moisture, these forages grow very rapidly during their appropriate growing seasons. Advantages and disadvantages of various annual forages, results of dryland and irrigated forage trials, tips for achieving quality forage, and issues related to animal health and feeding forages are discussed in this NebGuide.

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.

G03-1501 Prudent Use Of Antibiotics In Companion 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 companion animals.

Antibiotics are used to improve animal health and performance. You, as the animal owner or caregiver, make important decisions about how antibiotics are finally used in companion animals. Antibiotics should be used prudently to ensure they are effective and will continue to benefit man and animals in the future. Are you prepared to make the best decisions about using antibiotics in animals?