A meta-analysis of forest age and structure effects on northern flying squirrel densities

Research on the impact of clearcut logging and partial harvesting practices on northern flying squirrels (Glaucomys sabrinus) has shown inconsistent and contrary results, limiting the use of this species as a management indicator species. Much of this variability in study results is due to the labor intensive nature of studying flying squirrels, resulting in small sampling sizes (average = 5.2 sites, n = 14) and high variation (CV = 0.59) across studies. We conducted a meta-analysis of relevant studies from North America to determine how forestry practices affect flying squirrel abundance. Mean effect size was −1.18 (P < 0.001; n = 14) for all studies, indicating a strong difference between control stands and those regenerating postclearcut or following partial harvesting. Our results support the association of northern flying squirrels with mature, uncut forest and their suitability as ecological indicators of these vegetation types. © 2011 The Wildlife Society.     

Membrane Toxicity of Abnormal Prion Protein in Adrenal Chromaffin Cells of Scrapie Infected Sheep

Transmissible spongiform encephalopathies (TSEs) or prion diseases are associated with accumulations of disease specific PrP (PrP^d) in the central nervous system (CNS) and often the lymphoreticular system (LRS). Accumulations have additionally been recorded in other tissues including the peripheral nervous system and adrenal gland. Here we investigate the effect of sheep scrapie on the morphology and the accumulation of PrP^d in the adrenal medulla of scrapie affected sheep using light and electron microscopy. Using immunogold electron microscopy, non-fibrillar forms of PrP^d were shown to accumulate mainly in association with chromaffin cells, occasional nerve endings and macrophages. PrP^d accumulation was associated with distinctive membrane changes of chromaffin cells including increased electron density, abnormal linearity and invaginations. Internalisation of PrP^d from the chromaffin cell plasma membrane occurred in association with granule recycling following hormone exocytosis. PrP^d accumulation and internalisation from membranes is similarly associated with perturbations of membrane structure and trafficking in CNS neurons and tingible body macrophages of the LRS. These data suggest that a major toxic effect of PrP^d is at the level of plasma membranes. However, the precise nature of PrP^d-membrane toxicity is tissue and cell specific suggesting that the normal protein may act as a multi-functional scaffolding molecule. We further suggest that the co-localisation of PrP^d with exocytic granules of the hormone trafficking system may provide an additional source of infectivity in blood.     

Characterization of enterocin- and salivaricin-producing lactic acid bacteria from the mammalian gastrointestinal tract

Bacteriocin production may be a factor contributing to bacterial dominance within complex microbial populations and may therefore be a common trait within the gut microbiota. However, of 278 antimicrobial-producing culturable lactic acid bacteria (LAB) isolated from a range of mammalian intestinal sources in this study, characterization revealed just 23 distinct strains producing bacteriocin-like inhibitory substances and one Streptococcus hyointestinalis strain producing a potentially novel protease-insensitive antimicrobial. Three class II bacteriocins previously isolated from intestinal-derived LAB were identified as enterocin A and two salivaricin P-like bacteriocins. Moreover, this is the first report of intestinal-derived Streptococcus salivarius producing variants of the lantibiotic salivaricin A.     

The human LFA-3 gene is located at the same chromosome band as the gene for its receptor CD2

Lymphocyte function-associated antigen 3 (LFA-3) is a widely distributed cell surface glycoprotein that has been assigned a role in cell-cell adhesion on the basis of its capacity to bind to the T-lymphocyte CD2 antigen. The amino acid sequences of the extracellular domains of these two antigens, predicted from their cDNA sequences, show significant similarities, and both are members of the immunoglobulin supergene family. In this communication, a probe prepared from LFA-3 cDNA has been used in Southern blot analyses of somatic cell hybrids and in in situ hybridization to assign the LFA-3 gene to the human chromosome band 1p13. This is the same location previously assigned to CD2. Thus the LFA-3 and CD2 genes have probably arisen by duplication of a common evolutionary precursor. These genes therefore represent a further instance in which related members of the immunoglobulin superfamily are located in adjacent regions of the genome.     

Cardiac alpha-crystallin

Summary A major component of the soluble fraction of rat heart is a homopolymer (M_r about 400–650 k) of a small protein (M_r about 20 k). This cardiac protein, which is highly homologous to alpha-B-crystallin, was isolated in its native state and visualized by electron microscopy. A homogeneous population of globular particles with an average diameter of about 14-16 nM could be seen using either negative staining or rotary shadowing procedures. The structures were globular in nature with a central depression (torus-like structures). Polyclonal antibodies, raised against the cardiac crystallin, were used for the immunocytochemical localization of the macromolecular complexes. Using fluorescent secondary antibodies, a clear and sharp striation of fixed and permeabilized rat heart myocytes could be observed, similar to that observed with anti-desmin antibodies and characteristic for the central region of the I-band. Cardiac crystallin was not found associated with F-actin in preparations of rat heart myofibrils. On the other hand, it was a major contaminant of cardiac desmin preparations. These observations suggest that cardiac crystallin is involved in the organization of cytoskeletal filaments of the Z-lines.Abbreviations SDS Sodium Dodecyl Sulfate - SDS-PAGE SDS-Polyacrylamide Gel Electrophoresis - PMSF Phenyl Methyl Sulfonyl Fluoride - MOPS 3-Morpholino Propanesulfonic Acid - TX-100 Octyl Phenoxy Polyethoxyethanol - CHAPS (3-((3-Cholamidopropyl)Dimethylammonio)-1-Propanesulfonate), - BSA Bovine Serum Albumin - FITC Fluorescein Isothiocyanate - PO Peroxidase