Role of microglial cells in selective replication of simian immunodeficiency virus genotypes in the brain

An accelerated, consistent macaque simian immunodeficiency virus (SIV) model in which over 90% of pigtailed macaques (Macaca nemestrina) coinoculated with SIV/17E-Fr and SIV/DeltaB670 developed encephalitis was used to determine whether central nervous system (CNS) lesions are associated with the replication of specific genotypes in the brain and, more specifically, in the microglia. Ten of 11 inoculated macaques had severe (n = 3), moderate (n = 5), or mild (n = 2) encephalitis at 3 months postinoculation. To compare actively replicating viral genotypes in the CNS and in microglia with those in the periphery, the V1 region of the SIV envelope gene was amplified and sequenced from RNA extracted from basal ganglia, from microglial cells isolated from the brain, and from peripheral blood mononuclear cells (PBMC) isolated from blood at the time of death. To distinguish between actively replicating with latent viral genotypes in the CNS, viral genotypes in RNA and DNA from basal ganglia were compared. Two macrophage-tropic, neurovirulent viruses, SIV/17E-Fr and SIV/DeltaB670 Cl-2, predominated in the brain RNA of macaques with encephalitis, comprising 95% of the genotypes detected. The same two viral genotypes were present at the same frequencies in microglial cell RNA, suggesting that microglia are pivotal in the selective replication of neurovirulent viruses. There was a significantly greater number of viral genotypes in DNA than there were in RNA in the brain (P = 0.004), including those of both the macrophage- and lymphocyte-tropic viral strains. Furthermore, significantly fewer viral genotypes were detected in brain RNA than in PBMC RNA at the time of death (P = 0.004) and the viral strain that predominated in the brain frequently was different from that which predominated in the PBMC of the same animal. These data suggest that many viral genotypes enter the brain, but only a limited subset of macrophage-tropic, neurovirulent viruses replicate terminally in the brains of macaques with encephalitis. They further suggest that the selection of macrophage-tropic, neurovirulent viruses occurs not at the level of the blood-brain barrier but at a stage after virus entry and that microglial cells may play an important role in that selection process.     

The effects of pesticides on bacterial nitrogen fixers in peanut-growing area

In the peanut production, the applications of herbicides and fungicides are a common practice. In this work, studies done under field conditions demonstrated that pesticides affected negatively the number and nitrogenase activity of diazotrophic populations of soil. Agrochemical effects were not transient, since these parameters were not recovered to pre-treatment levels even 1 year after pesticides application. Results obtained from greenhouse experiments revealed that the addition of herbicide or fungicides diminished the free-living diazotrophs number reaching levels found in soil amended with the pesticides and that the number of symbiotic diazotrophs was not affected by the insecticide assayed. The soil nitrogenase activity was not affected by fungicides and glyphosate. The effect of pesticides on the nitrogen-fixing bacteria diversity was evaluated both in field and greenhouse experiments. Analysis of clone libraries generated from the amplification of soil nifH gene showed a diminution in the genetic diversity of this bacterial community.     

Amyloid aggregation of lysozyme: The synergy study of red wine polyphenols

The amyloidoses are diseases associated with nonnative folding of proteins and characterized by the presence of protein amyloid aggregates. The ability of quercetin, resveratrol, caffeic acid, and their equimolar mixtures to affect amyloid aggregation of hen egg white lysozyme in vitro was detected by Thioflavin T fluorescence assay. The anti‐amyloid activities of tested polyphenols were evaluated by the median depolymerization concentrations DC₅₀ and median inhibition concentrations IC₅₀. Single substances are more efficient (by at least one order) in the depolymerization of amyloid aggregates assay than in the inhibition of the amyloid formation with IC₅₀ in 10^?4 to 10^?5M range. Analyzed mixture samples showed synergic or antagonistic effects in both assays. DC₅₀ values ranged from 10^?5 to 10^?8M and IC₅₀ from 10^?5 to 10^?9M, respectively. We observed that certain mixtures of studied polyphenols can synergistically inhibit production of amyloids aggregates and are also effective in depolymerization of the aggregates. Synergic or antagonistic effects of studied mixtures were correlated with protein–small ligand docking studies and AFM results. Differences in these activities could be explained by binding of each polyphenol to a different amino acid sequence within the protein. Our results indicate that synergic/antagonistic anti‐amyloid effects of studied mixtures depend on the selective binding of polyphenols to the known amyloidogenic sequences in the lysozyme chain. Our findings of the effective reduction of amyloid aggregation of lysozyme by polyphenol mixtures in vitro are of the utter physiological relevance considering the bioavailability and low toxicity of tested phenols. Proteins 2013; © 2012 Wiley Periodicals, Inc.     

NFκB mediated elevation of KCNJ11 promotes tumor progression of hepatocellular carcinoma through interaction of lactate dehydrogenase A

It has been well documented that changes in ion fluxes across cellular membranes is fundamental in maintaining cellular homeostasis. Dysregulation and/or malfunction of ion channels are critical events in the pathogenesis of diverse diseases, including cancers. In this study, we focused on the study of K⁺ channels in hepatocellular carcinoma (HCC). By data mining TCGA cohort, the expression of 27 K⁺ channels was investigated and KCNJ11 was identified as a key dysregulated K⁺ channels in HCC. KCNJ11 was differentially expressed in HCC and predicted a poor prognosis in HCC patients. Inhibition of NFκB signaling suppressed KCNJ11 expression in HCC cells. Knockdown of KCNJ11 expression inhibited cell proliferation, promoted cell apoptosis, and reduced cell invasive capacity. Mechanistically, we found that KCNJ11 promotes tumor progression through interaction with LDHA and enhancing its enzymatic activity. Pharmacological inhibition of LDHA largely compromised the oncogenic function of KCNJ11 in cell proliferation, cell apoptosis, and cell invasion. Collectively, our data, as a proof of principle, demonstrate that KCNJ11 acts as an oncogene in HCC though forming a complex with LDHA and suggest that targeting KCNJ11 can be developed as a candidate tool to dampen HCC.     

Novel naftopidil derivatives containing methyl phenylacetate and their blocking effects on α1D/1A-adrenoreceptor subtypes

α₁-Adrenoceptor (α₁-AR) antagonists are considered to be the most effective monotherapy agents for lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH). In this study, we synthesized compounds 2–17, which are novel piperazine derivatives that contain methyl phenylacetate. We then evaluated the vasodilatory activities of these compounds. Among them, we found that compounds 2, 7, 12, which contain 2-OCH₃, 2-CH₃ or 2, 5-CH₃, respectively, exhibited potent α₁-blocking activity similar to protype drug naftopidil (1). The antagonistic effects of 2, 7, and 12 on the (?)-noradrenaline-induced contractile response of isolated rat prostatic vas deferens (α_1A), spleen (α_1B) and thoracic aorta (α_1D) were further characterized to assess the sub receptor selectivity. Compared with naftopidil (1) and terazosin, compound 12 showed the most desirable α_1D/1A subtype selectivity, especially improved α_1A subtype selectivity, and the ratios pA₂ (α_1D)/pA₂ (α_1B) and pA₂ (α_1A)/pA₂ (α_1B) were 17.0- and 19.5-fold, respectively, indicating less cardiovascular side effects when used to treat LUTS/BPH. Finally, we investigated the chiral pharmacology of 12. We found, however, that the activity of enantiomers (R)-12 and (S)-12 are not significantly different from that of rac-12.     

Achieving High Open‐Circuit Voltages up to 1.57 V in Hole‐Transport‐Material‐Free MAPbBr3 Solar Cells with Carbon Electrodes

An open‐circuit voltage (V_oc) of 1.57 V under simulated AM1.5 sunlight in planar MAPbBr₃ solar cells with carbon (graphite) electrodes is obtained. The hole‐transport‐material‐free MAPbBr₃ solar cells with the normal architecture (FTO/TiO₂/MAPbBr₃/carbon) show little hysteresis during current–voltage sweep under simulated AM1.5 sunlight. A solar‐to‐electricity power conversion efficiency of 8.70% is achieved with the champion device. Accordingly, it is proposed that the carbon electrodes are effective to extract photogenerated holes in MAPbBr₃ solar cells, and the industry‐applicable carbon electrodes will not limit the performance of bromide‐based perovskite solar cells. Based on the analysis of the band alignment, it is found that the voltage (energy) loss across the interface between MAPbBr₃ and carbon is very small compared to the offset between the valence band maximum of MAPbBr₃ and the work function of graphite. This finding implies either Fermi level pinning or highly doped region inside MAPbBr₃ layer exists. The band‐edge electroluminescence spectra of MAPbBr₃ from the solar cells further support no back‐transfer pathways of electrons across the MAPbBr₃/TiO₂ interface.     

Exogenous silicon (Si) increases antioxidant enzyme activity and reduces lipid peroxidation in roots of salt-stressed barley (Hordeum vulgare L.)

Two contrasting barley (Hordeum vulgare L.) cultivars, i.e. Kepin No.7 (salt sensitive) and Jian 4 (salt tolerant), were grown hydroponically to study the effect of exogenous silicon (Si) on time dependent changes of the activities of major antioxidant enzymes and of lipid peroxidation in roots under salt stress. Enzymes included: superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and glutathione reductase (GR). Three treatments with three replicates were investigated consisting of a control (basal nutrients with neither NaCl nor Si added), 120 mmol/L-1 NaCl, and 120 mmol/L-1 NaCl +1.0 mmol/L-1 Si. Plant roots were harvested 2, 4 and 6 days after treatment and assayed for activities of the antioxidant enzymes and the concentrations of reduced glutathione (GSH) and malondialdehyde (MDA), and electrolytic leakage percentage (ELP). The activities of SOD, POD and CAT in roots of salt-stressed plants were significantly stimulated at Day 2 compared to control plants, but considerably decreased at Day 4 and onward. GR activity in roots of salt-stressed plants remained unchanged at Day 2, but significantly decreased at Day 4 and onward. However, exogenous Si significantly enhanced these enzyme activities in roots of salt-stressed plants compared to Si-deprived salt treatments. This Si effect was time-dependent and became stronger as the experiments continued. The tendency of change in the activities of antioxidant enzymes and the concentration of GSH coincided with the concentration of MDA, the end product of lipid peroxidation, and the ELP. Higher activities of antioxidant enzymes, and higher concentration of GSH, but lower concentration of MDA and lower ELP were noted in cultivar Jian 4 compared to Kepin No. 7, implying genotypic differences with Jian 4 being less susceptible to stress-dependent membrane lipid peroxidation. The effects of Si-enhanced salt tolerance are discussed with respect to cell membrane integrity, stability and function in barley.