Variation in the free amino acid content of skeletal muscle of Ophicephalus punctatus (Bloch)

The skeletal muscle of Ophicephalus punctatus contains nine essential free amino acids, arginine, histidine, isoleucine, leucine, methionine, phenylalanine, threonine, valine and lysine, and eight non-essential amino acids, alanine, aspartic acid, cystine, glutamic acid, glycine, tyrosine, proline and serine. Histidine and lysine dominated the free amino acids pool. Seasonal variation was detected in the levels of histidine, arginine, leucine, phenylalanine, glycine, cystine and serine with highest values occurring in April and again in November. Changes were also detected in the concentrations of certain amino acids as the fish grew in size. Levels of free amino acids did not significantly differ between sexes. Factors effecting variation are discussed.     

Predicting protein subcellular location: exploiting amino acid based sequence of feature spaces and fusion of diverse classifiers

A novel approach CE-Ploc is proposed for predicting protein subcellular locations by exploiting diversity both in feature and decision spaces. The diversity in a sequence of feature spaces is exploited using hydrophobicity and hydrophilicity of amphiphilic pseudo amino acid composition and a specific learning mechanism. Diversity in learning mechanisms is exploited by fusion of classifiers that are based on different learning mechanisms. Significant improvement in prediction performance is observed using jackknife and independent dataset tests.     

Photosynthetic activity of developing leaves of Zea mays is less affected by heat stress than that of developed leaves

Various physiological and biochemical characters of a leaf change with stages of its ontogeny. It is likely that the photosynthetic functions of leaves of different ontogeny have different levels of heat tolerance. This study was initiated to analyze the photosynthetic heat tolerance of fully-developed, nearly-developed (more than 2/3 expanded) and developing (10–12 cm visible) leaves of two maize genotypes, F223 and F250. The results indicate that the photosynthetic CO₂ assimilation rate (P_n) of developing leaves was less affected by heat stress (42°C in the dark for 90 min) than that of developed leaves. The impaired P_n recovered within 24 h in the developing leaves, while the P_n of developed and nearly-developed leaves did not reach the non-stress level, even after 72 h. The P_n of the developed leaves of genotype F250 was less affected by heat stress than that of genotype F223. After heat stress, the slightly affected P_n of the developing leaf was associated with the almost unchanged photochemical efficiency of photosystem II (F_v/F_m) and the quantum yield of photosystem II electron transport. The chlorophylls a and b were degraded by heat stress; the degradation was pronounced in the developed leaves. As a result of heat stress, the antheraxanthin and zeaxanthin of the xanthophyll cycle accumulated in both the nearly-developed and developed leaves but not in the developing leaves. Injury to the plasma membrane due to heat stress was much less severe in developing leaves than that in the developed leaves. From the physiological characters which we determined it would appear that the P_n functions of the developing leaves are more resistant to heat stress than those of nearly-developed and developed leaves.     

The P2X7 receptor and intracellular pathogens: a continuing struggle

The purinergic receptor, P2X₇, has recently emerged as an important component of the innate immune response against microbial infections. Ligation of P2X₇ by ATP can stimulate inflammasome activation and secretion of proinflammatory cytokines, but it can also lead directly to killing of intracellular pathogens in infected macrophages and epithelial cells. Thus, while some intracellular pathogens evade host defense responses by modulating with membrane trafficking or cell signaling in the infected cells, the host cells have also developed mechanisms for inhibiting infection. This review will focus on the effects of P2X₇ on control of infection by intracellular pathogens, microbial virulence factors that interfere with P2X₇ activity, and recent evidence linking polymorphisms in human P2X₇ with susceptibility to infection.     

Chromium-resistant bacteria and cyanobacteria: impact on Cr(VI) reduction potential and plant growth

Two chromium-resistant bacterial strains, Bacillus cereus S-6 and Ochrobactrum intermedium CrT-1, and two cyanobacterial strains, Oscillatoria sp. and Synechocystis sp., were used in this study. At initial chromate concentrations of 300 and 600 μg K₂CrO₄ mL⁻¹, and an inoculum size of 9.6×10⁷ cells mL⁻¹, B. cereus S-6 completely reduced Cr(VI), while O. intermedium CrT-1 reduced Cr(VI) by 98% and 70%, respectively after 96 h. At 100 μg K₂CrO₄ mL⁻¹, Synechocystis sp. MK(S) and Oscillatoria sp. BJ2 reduced 62.1% and 39.9% of Cr(VI), respectively, at 30°C and pH 8. Application of hexavalent chromate salts adversely affected wheat seedling growth and anatomical characters. However, bacterial inoculation alleviated the toxic effects, as reflected by significant improvements in growth as well as anatomical parameters. Cyanobacterial strains also led to some enhancement of various growth parameters in wheat seedlings.

     

New lipoxygenase-inhibiting constituents from Calligonum polygonoides

Calligonolides A (1) and B (2), two new butanolides, and a new steroidal ester, 3, have been isolated from the whole plant of Calligonum polygonoides, together with four known compounds, tetracosan-4-olide, beta-sitosterol and its glucoside, and ursolic acid. Their structures were elucidated by spectroscopic and mass-spectrometric studies. Compounds 1-3 showed moderate inhibitory potential against lipoxygenase from soybean.     

Safety of the Recombinant Cholera Toxin B Subunit, Killed Whole-Cell (rBS-WC) Oral Cholera Vaccine in Pregnancy

Introduction

Mass vaccinations are a main strategy in the deployment of oral cholera vaccines. Campaigns avoid giving vaccine to pregnant women because of the absence of safety data of the killed whole-cell oral cholera (rBS-WC) vaccine. Balancing this concern is the known higher risk of cholera and of complications of pregnancy should cholera occur in these women, as well as the lack of expected adverse events from a killed oral bacterial vaccine.

Methodology/Principal Findings

From January to February 2009, a mass rBS-WC vaccination campaign of persons over two years of age was conducted in an urban and a rural area (population 51,151) in Zanzibar. Pregnant women were advised not to participate in the campaign. More than nine months after the last dose of the vaccine was administered, we visited all women between 15 and 50 years of age living in the study area. The outcome of pregnancies that were inadvertently exposed to at least one oral cholera vaccine dose and those that were not exposed was evaluated. 13,736 (94%) of the target women in the study site were interviewed. 1,151 (79%) of the 1,453 deliveries in 2009 occurred during the period when foetal exposure to the vaccine could have occurred. 955 (83%) out of these 1,151 mothers had not been vaccinated; the remaining 196 (17%) mothers had received at least one dose of the oral cholera vaccine. There were no statistically significant differences in the odds ratios for birth outcomes among the exposed and unexposed pregnancies.

Conclusions/Significance

We found no statistically significant evidence of a harmful effect of gestational exposure to the rBS-WC vaccine. These findings, along with the absence of a rational basis for expecting a risk from this killed oral bacterial vaccine, are reassuring but the study had insufficient power to detect infrequent events.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00709410","term_id":"NCT00709410"}}NCT00709410     

γ-Secretase Processing and Effects of γ-Secretase Inhibitors and Modulators on Long Aβ Peptides in Cells

Understanding how different species of Aβ are generated by γ-secretase cleavage has broad therapeutic implications, because shifts in γ-secretase processing that increase the relative production of Aβx-42/43 can initiate a pathological cascade, resulting in Alzheimer disease. We have explored the sequential stepwise γ-secretase cleavage model in cells. Eighteen BRI2-Aβ fusion protein expression constructs designed to generate peptides from Aβ1–38 to Aβ1–55 and C99 (CTFβ) were transfected into cells, and Aβ production was assessed. Secreted and cell-associated Aβ were detected using ELISA and immunoprecipitation MALDI-TOF mass spectrometry. Aβ peptides from 1–38 to 1–55 were readily detected in the cells and as soluble full-length Aβ proteins in the media. Aβ peptides longer than Aβ1–48 were efficiently cleaved by γ-secretase and produced varying ratios of Aβ1–40:Aβ1–42. γ-Secretase cleavage of Aβ1–51 resulted in much higher levels of Aβ1–42 than any other long Aβ peptides, but the processing of Aβ1–51 was heterogeneous with significant amounts of shorter Aβs, including Aβ1–40, produced. Two PSEN1 variants altered Aβ1–42 production from Aβ1–51 but not Aβ1–49. Unexpectedly, long Aβ peptide substrates such as Aβ1–49 showed reduced sensitivity to inhibition by γ-secretase inhibitors. In contrast, long Aβ substrates showed little differential sensitivity to multiple γ-secretase modulators. Although these studies further support the sequential γ-secretase cleavage model, they confirm that in cells the initial γ-secretase cleavage does not precisely define subsequent product lines. These studies also raise interesting issues about the solubility and detection of long Aβ, as well as the use of truncated substrates for assessing relative potency of γ-secretase inhibitors.