Decreased virulence in stable,acapsular mutants ofCryptococcus neoformans

Six acapsular strains ofCryptococcus neoformans obtained by chemical mutagenesis failed to produce a capsulein vivo and were avirulent in mice following high dose intramuscular, intraperitoneal or intravenous inoculation. Peritoneal granulomas were observed in all animals inoculated with the acapsular mutants. These granulomas were characterized by a large central mass consisting of intact, degenerating and necrotic yeast cells. This was surrounded by concentric layers of a broad band of histiocytes, a narrow band of fibroblasts, and around the periphery, a mass of lymphocytes and plasma cells. These isolates did not revert to an encapsulated or virulent state after more than a year of subculturing or 18 passages through mice.     

Measurement of the Membrane Potential of Isolated Nerve Terminals by the Lipophilic Cation [3H]Triphenylmethylphosphonium Bromide

Abstract: The lipophilic cation [³H]triphenylrnethylphosphonium bromide ([³H]TPMP⁺) was investigated as a measure of the membrane potential of synaptosomes. Conditions under which [³H]TPMP⁺ achieved an equilibrium distribution were tested. The toxicity of TPMP has been studied relative to its inhibitory effects on [³H]y-aminobutyric acid ([³H]GABA) transport. In some experiments the distribution of ⁸⁶RbZ⁺ and [³H]TPMP⁺ was changed upon incubation in the presence of elevated levels of K⁺, ouabain, or KCN, or at 0°C in a way that would be expected from the membrane potential. In normal incubation conditions a membrane potential of ∼−60 mv was calculated.     

Intraspecific genetic variation of a Fagus sylvatica population in a temperate forest derived from airborne imaging spectroscopy time series

1. The growing pace of environmental change has increased the need for large‐scale monitoring of biodiversity. Declining intraspecific genetic variation is likely a critical factor in biodiversity loss, but is especially difficult to monitor: assessments of genetic variation are commonly based on measuring allele pools, which requires sampling of individuals and extensive sample processing, limiting spatial coverage. Alternatively, imaging spectroscopy data from remote platforms may hold the potential to reveal genetic structure of populations. In this study, we investigated how differences detected in an airborne imaging spectroscopy time series correspond to genetic variation within a population of Fagus sylvatica under natural conditions.
2. We used multi‐annual APEX (Airborne Prism Experiment) imaging spectrometer data from a temperate forest located in the Swiss midlands (Laegern, 47°28'N, 8°21'E), along with microsatellite data from F. sylvatica individuals collected at the site. We identified variation in foliar reflectance independent of annual and seasonal changes which we hypothesize is more likely to correspond to stable genetic differences. We established a direct connection between the spectroscopy and genetics data by using partial least squares (PLS) regression to predict the probability of belonging to a genetic cluster from spectral data.
3. We achieved the best genetic structure prediction by using derivatives of reflectance and a subset of wavebands rather than full‐analyzed spectra. Our model indicates that spectral regions related to leaf water content, phenols, pigments, and wax composition contribute most to the ability of this approach to predict genetic structure of F. sylvatica population in natural conditions.
4. This study advances the use of airborne imaging spectroscopy to assess tree genetic diversity at canopy level under natural conditions, which could overcome current spatiotemporal limitations on monitoring, understanding, and preventing genetic biodiversity loss imposed by requirements for extensive in situ sampling.

     

Robust Selection of the Most Discriminative Variables in the Dichotomous Problem with Application to Some Respiratory Disease Data

A robust method for selection of variables with the greatest discriminatory power is presented in the paper. The method deals with the two groups of data problem. An application of the method to some respiratory disease data and comparisons with classical procedures are given, also.     

Antioxidants and antioxidant enzymes protect against pulmonary oxygen toxicity in the rabbit

Two major lines of defense exist against oxidant lung injury: tissue antioxidants and antioxidant enzymes. We studied pretreatment with the antioxidants, vitamin E and butylated hydroxyanisole (BHA), and the antioxidant enzymes, superoxide dismutase (SOD) and catalase, in rabbits exposed to 100% O2 for 48 h. BHA (200 mg/kg ip) or vitamin E (50-100 mg/kg po) were given for 2 or 3 days, respectively, before O2 exposure. Combined therapy with polyethylene glycol- (PEG) conjugated SOD (12 mg/kg) and catalase (200,000 U/kg) was given intraperitoneally 1 h before and 24 h after beginning 100% O2. Hyperoxia significantly increased the pulmonary content of malondialdehyde, indicating enhanced lipid peroxidation. One hundred percent O2 also increased lung weight gain and alveolar-capillary permeability to aerosolized 99mTc-labeled diethylenetriaminepentaacetate (99mTc-DTPA, 500 mol wt) and fluorescein isothiocyanate-labeled dextran (7,000 mol wt). Pretreatment with vitamin E, BHA, or the combination of PEG-SOD and PEG-catalase prevented the increase in malondialdehyde, lung weight gain, and alveolar-capillary permeability caused by hyperoxia. These results indicate that augmenting either tissue antioxidants or antioxidant enzymes can prevent the pulmonary injury caused by 48 h of 100% O2 in rabbits.     

The mouse Fc receptor for IgG (Ly-17) : molecular cloning and specificity

A cDNA clone encoding the mouse Ly-17⁺ Fc receptor for IgG, isolated from a myelomonocytic cell line, was sequenced and expression of mRNA and the functional FcR investigated. The receptor is a 301 amino acid transmembrane glycoprotein with two homologous extracellular domains that are also homologous to members of the Ig superfamily. The receptor has four sites of N-linked glycosylation and a long 94 amino acid cytoplasmic tail. Northern analysis, immune complex binding, and serological studies demonstrate that the receptor encoded by the cDNA clone binds mouse IgG_1/2b and rabbit IgG complexes.     

Immunoaffinity-purified opiate receptor specifically binds the delta-class opiate receptor ligand, cis-(+)-3-methylfentanylisothiocyanate, SUPERFIT

Using an antibody generated against the opiate receptor on NG108-15 cells, we recently purified the putative receptor from this hybrid cell line. We herein report that the purified receptor complex specifically binds tritiated cis-(+)-3-methylfentanylisothiocyanate (SUPERFIT), with the predominant binding associated with a 58 kDa polypeptide chain. Consistent with these findings is the in situ labeling of a 58 kDa protein with [3H]SUPERFIT on NG108-15 cells.