Protective Role of Quercetin on Polychlorinated Biphenyls (Aroclor‐1254) Induced Oxidative Stress and Apoptosis in Liver of Adult Male Rats

The present study aims to investigate the protective effect of quercetin against Aroclor‐1254–induced hepatotoxicity in rats. Male Wistar rats were grouped into Group I control received vehicle (corn oil; 1 mL/kg bwt); Group II quercetin alone (50 mg/kg bwt/day orally); Group III Aroclor‐1254 (2 mg/kg bwt/day intraperitoneally); Group IV Aroclor‐1254 + quercetin treated for 30 days. The Aroclor‐1254 treatment caused significant alteration in the biochemical parameters (hydrogen peroxide, lipid peroxidation, reduced glutathione levels, and alkaline phosphatase activity). The expressions of apoptotic and antiapoptotic proteins and the liver histology of Aroclor‐1254–exposed rats showed cytoplasmic degeneration along with infiltration of polymorphonuclear cells. Whereas simultaneous treatment with quercetin normalized all the biochemical parameters, consequently it inhibited apoptosis mediated by Aroclor‐1254 by downregulating aryl hydrocarbon receptor, p53 and apoptotic protein (Bax, caspase‐9, caspase‐3) and upregulating the antiapoptotic protein (Bcl‐2) expression patterns; thereby, quercetin reduces alteration in hepatocellular morphology. Thus quercetin exhibited hepatoprotective effect. © 2012 Wiley Periodicals, Inc. J BiochemMol Toxicol 26:522‐532, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21466     

Rhinovirus Attenuates Non-typeable Hemophilus influenzae-stimulated IL-8 Responses via TLR2-dependent Degradation of IRAK-1

Bacterial infections following rhinovirus (RV), a common cold virus, are well documented, but pathogenic mechanisms are poorly understood. We developed animal and cell culture models to examine the effects of RV on subsequent infection with non-typeable Hemophilus influenzae (NTHi). We focused on NTHI-induced neutrophil chemoattractants expression that is essential for bacterial clearance. Mice infected with RV1B were superinfected with NTHi and lung bacterial density, chemokines and neutrophil counts determined. Human bronchial epithelial cells (BEAS-2B) or mouse alveolar macrophages (MH-S) were infected with RV and challenged with NHTi, TLR2 or TLR5 agonists. Chemokine levels were measured by ELISA and expression of IRAK-1, a component of MyD88-dependent TLR signaling, assessed by immunoblotting. While sham-infected mice cleared all NTHi from the lungs, RV-infected mice showed bacteria up to 72 h post-infection. However, animals in RV/NTHi cleared bacteria by day 7. Delayed bacterial clearance in RV/NTHi animals was associated with suppressed chemokine levels and neutrophil recruitment. RV-infected BEAS-2B and MH-S cells showed attenuated chemokine production after challenge with either NTHi or TLR agonists. Attenuated chemokine responses were associated with IRAK-1 protein degradation. Inhibition of RV-induced IRAK-1 degradation restored NTHi-stimulated IL-8 expression. Knockdown of TLR2, but not other MyD88-dependent TLRs, also restored IRAK-1, suggesting that TLR2 is required for RV-induced IRAK-1 degradation.In conclusion, we demonstrate for the first time that RV infection delays bacterial clearance in vivo and suppresses NTHi-stimulated chemokine responses via degradation of IRAK-1. Based on these observations, we speculate that modulation of TLR-dependent innate immune responses by RV may predispose the host to secondary bacterial infection, particularly in patients with underlying chronic respiratory disorders.     

Hepatitis B vaccine antibody response and the risk of clinical AIDS or death

Background

Whether seroresponse to a vaccine such as hepatitis B virus (HBV) vaccine can provide a measure of the functional immune status of HIV-infected persons is unknown.This study evaluated the relationship between HBV vaccine seroresponses and progression to clinical AIDS or death.

Methods and Findings

From a large HIV cohort, we evaluated those who received HBV vaccine only after HIV diagnosis and had anti-HBs determination 1–12 months after the last vaccine dose. Non-response and positive response were defined as anti-HBs <10 and ≥10 IU/L, respectively. Participants were followed from date of last vaccination to clinical AIDS, death, or last visit. Univariate and multivariable risk of progression to clinical AIDS or death were evaluated with Cox regression models. A total of 795 participants vaccinated from 1986–2010 were included, of which 41% were responders. During 3,872 person-years of observation, 122 AIDS or death events occurred (53% after 1995). Twenty-two percent of non-responders experienced clinical AIDS or death compared with 5% of responders (p<0.001). Non-response to HBV vaccine was associated with a greater than 2-fold increased risk of clinical AIDS or death (HR 2.47; 95% CI, 1.38–4.43) compared with a positive response, after adjusting for CD4 count, HIV viral load, HAART use, and delayed type hypersensitivity skin test responses (an in vivo marker of cell-mediated immunity). This association remained evident among those with CD4 count ≥500 cells/mm³ (HR 3.40; 95% CI, 1.39–8.32).

Conclusions

HBV vaccine responses may have utility in assessing functional immune status and risk stratificating HIV-infected individuals, including those with CD4 count ≥500 cells/mm³.     

RSARF: prediction of residue solvent accessibility from protein sequence using random forest method

Prediction of protein structure from its amino acid sequence is still a challenging problem. The complete physicochemical understanding of protein folding is essential for the accurate structure prediction. Knowledge of residue solvent accessibility gives useful insights into protein structure prediction and function prediction. In this work, we propose a random forest method, RSARF, to predict residue accessible surface area from protein sequence information. The training and testing was performed using 120 proteins containing 22006 residues. For each residue, buried and exposed state was computed using five thresholds (0%, 5%, 10%, 25%, and 50%). The prediction accuracy for 0%, 5%, 10%, 25%, and 50% thresholds are 72.9%, 78.25%, 78.12%, 77.57% and 72.07% respectively. Further, comparison of RSARF with other methods using a benchmark dataset containing 20 proteins shows that our approach is useful for prediction of residue solvent accessibility from protein sequence without using structural information. The RSARF program, datasets and supplementary data are available at http://caps.ncbs.res.in/download/pugal/RSARF/.     

Overexpression of phytochrome A and its hyperactive mutant improves shade tolerance and turf quality in creeping bentgrass and zoysiagrass

Phytochrome A (phyA) in higher plants is known to function as a far-red/shade light-sensing photoreceptor in suppressing shade avoidance responses (SARs) to shade stress. In this paper, the Avena PHYA gene was introduced into creeping bentgrass (Agrostis stolonifera L.) and zoysiagrass (Zoysia japonica Steud.) to improve turf quality by suppressing the SARs. In addition to wild-type PHYA, a hyperactive mutant gene (S599A-PHYA), in which a phosphorylation site involved in light-signal attenuation was removed, was also transformed into the turfgrasses. Phenotypic traits of the transgenic plants were compared to assess the suppression of SARs under a simulated shade condition and outdoor field conditions after three growth seasons. Under the shade condition, the S599A-PhyA transgenic creeping bentgrass plants showed shade avoidance-suppressing phenotypes with a 45?% shorter leaf lengths, 24?% shorter internode lengths, and twofold increases in chlorophyll concentrations when compared with control plants. Transgenic zoysiagrass plants overexpressing S599A-PHYA also showed shade-tolerant phenotypes under the shade condition with reductions in leaf length (15?%), internode length (30?%), leaf length/width ratio (19?%) and leaf area (22?%), as well as increases in chlorophyll contents (19?%) and runner lengths (30?%) compared to control plants. The phenotypes of transgenic zoysiagrass were also investigated in dense field habitats, and the transgenic turfgrass exhibited shade-tolerant phenotypes similar to those observed under laboratory shade conditions. Therefore, the present study suggests that the hyperactive phyA is effective for the development of shade-tolerant plants, and that the shade tolerance nature is sustained under field conditions.     

Fish oil and indomethacin in combination potently reduce dyslipidemia and hepatic steatosis in LDLR -/- mice

Fish oil (FO) is a potent anti-inflammatory and lipid-lowering agent. Because inflammation can modulate lipid metabolism and vice versa, we hypothesized that combining FO with cyclooxygenase inhibitors (COXIBs), well-known anti-inflammatory drugs, can enhance the anti-inflammatory and lipid-lowering effect of FO. LDLR (-/-) mice were fed a high-fat diet supplemented with 6% olive oil or FO for 12 wk in the presence or absence of indomethacin (Indo, 6 mg/l drinking water). FO reduced plasma total cholesterol by 30% but, in combination with Indo, exerted a greater decrease (44%). The reduction of liver cholesterol ester (CE) and triglycerides (TG) by FO (63% and 41%, respectively) was enhanced by Indo (80% in CE and 64% in TG). FO + Indo greatly increased the expression of genes modulating lipid metabolism and reduced the expression of inflammatory genes compared with control. The mRNA and/or protein expression of pregnane X receptor (PXR) and cytochrome P450 isoforms that alter inflammation and/or lipid metabolism are increased to a greater extent in mice that received FO + Indo. Moroever, the nuclear level of PXR is significantly increased in FO + Indo group. Combining FO with COXIBs may exert their beneficial effects on inflammation and lipid metabolism via PXR and cytochrome P450.     

Somatic embryogenesis and plant regeneration of <Emphasis Type="Italic">Abelmoschus esculentus</Emphasis> through suspension culture

A simple and reliable protocol for regeneration of okra through somatic embryogenesis from suspension cultures has been developed. Embryogenic callus was obtained from hypocotyl explants cultured on media with Murashige and Skoog (MS) salts, Gamborg (B5) vitamins, 2.0 mg dm⁻³ 2,4-dichlorophenoxyacetic acid (2,4-D), 1.0 mg dm⁻³ naphthaleneacetic acid (NAA), 25 mg dm⁻³ polyvinylpyrrolidone and 30 g dm⁻³ sucrose. More number and high frequency of healthy embryoids appeared individually in suspension culture containing MS salts, B5 vitamins, 2.0 mg dm⁻³ 2,4-D and 1.0 mg dm⁻³ kinetin. Formation of cell clusters from the single cells was clearly noticed during ontogeny. Matured embryos at the cotyledonary stage were transferred to agar solidified medium for germination. The best conversion of embrya into plantlets (67.3 %) was recorded on media with half strength MS salts, B5 vitamins, 0.2 mg dm⁻³ benzylaminopurine (BAP) and 0.2 mg dm⁻³ gibberellic acid (GA₃). The plantlets were transferred to soil and hardened in the plastic pots. After proper acclimatization, the plantlets regenerated through somatic embryogenesis were compared to seed grown plants to observe any variation.     

Analysis of breast cancer progression using principal component analysis and clustering

We develop a new technique to analyse microarray data which uses a combination of principal components analysis and consensus ensemble k-clustering to find robust clusters and gene markers in the data. We apply our method to a public microarray breast cancer dataset which has expression levels of genes in normal samples as well as in three pathological stages of disease; namely, atypical ductal hyperplasia or ADH, ductal carcinoma in situ or DCIS and invasive ductal carcinoma or IDC. Our method averages over clustering techniques and data perturbation to find stable, robust clusters and gene markers. We identify the clusters and their pathways with distinct subtypes of breast cancer (Luminal,Basal and Her2+). We confirm that the cancer phenotype develops early (in early hyperplasia or ADH stage) and find from our analysis that each subtype progresses from ADH to DCIS to IDC along its own specific pathway, as if each was a distinct disease.