Hepatitis C virus NS5A binds to the mRNA cap-binding eukaryotic translation initiation 4F (eIF4F) complex and up-regulates host translation initiation machinery through eIF4E-binding protein 1 inactivation

Initiation, a major rate-limiting step of host protein translation, is a critical target in many viral infections. Chronic hepatitis C virus (HCV) infection results in hepatocellular carcinoma. Translation initiation, up-regulated in many cancers, plays a critical role in tumorigenesis. mTOR is a major regulator of host protein translation. Even though activation of PI3K-AKT-mTOR by HCV non-structural protein 5A (NS5A) is known, not much is understood about the regulation of host translation initiation by this virus. Here for the first time we show that HCV up-regulates host cap-dependent translation machinery in Huh7.5 cells through simultaneous activation of mTORC1 and eukaryotic translation initiation factor 4E (eIF4E) by NS5A. NS5A, interestingly, overexpressed and subsequently hyperphosphorylated 4EBP1. NS5A phosphorylated eIF4E through the p38 MAPK-MNK pathway. Both HCV infection and NS5A expression augmented eIF4F complex assembly, an indicator of cap-dependent translation efficiency. Global translation, however, was not altered by HCV NS5A. 4EBP1 phosphorylation, but not that of S6K1, was uniquely resistant to rapamycin in NS5A-Huh7.5 cells, indicative of an alternate phosphorylation mechanism of 4EBP1. Resistance of Ser-473, but not Thr-308, phosphorylation of AKT to PI3K inhibitors suggested an activation of mTORC2 by NS5A. NS5A associated with eIF4F complex and polysomes, suggesting its active involvement in host translation. This is the first report that implicates an HCV protein in the up-regulation of host translation initiation apparatus through concomitant regulation of multiple pathways. Because both mTORC1 activation and eIF4E phosphorylation are involved in tumorigenesis, we propose that their simultaneous activation by NS5A might contribute significantly to the development of hepatocellular carcinoma.     

The Coronatine Toxin of Pseudomonas syringae Is a Multifunctional Suppressor of Arabidopsis Defense

The phytotoxin coronatine (COR) promotes various aspects of Pseudomonas syringae virulence, including invasion through stomata, growth in the apoplast, and induction of disease symptoms. COR is a structural mimic of active jasmonic acid (JA) conjugates. Known activities of COR are mediated through its binding to the F-box–containing JA coreceptor CORONATINE INSENSITIVE1. By analyzing the interaction of P. syringae mutants with Arabidopsis thaliana mutants, we demonstrate that, in the apoplastic space of Arabidopsis, COR is a multifunctional defense suppressor. COR and the critical P. syringae type III effector HopM1 target distinct signaling steps to suppress callose deposition. In addition to its well-documented ability to suppress salicylic acid (SA) signaling, COR suppresses an SA-independent pathway contributing to callose deposition by reducing accumulation of an indole glucosinolate upstream of the activity of the PEN2 myrosinase. COR also suppresses callose deposition and promotes bacterial growth in coi1 mutant plants, indicating that COR may have multiple targets inside plant cells.     

Dendritic cell-mediated induction of mucosal cytotoxic responses following intravaginal immunization with the nontoxic B subunit of cholera toxin

The use of the nontoxic B subunit of cholera toxin (CTB) as mucosal adjuvant and carrier-delivery system for inducing secretory Ab responses has been documented previously with different soluble Ags. In this study, we have evaluated this approach for inducing CTL responses against a prototype Ag, OVA, in the female genital mucosa. We report here the ability of an immunogen comprised of CTB conjugated to OVA (CTB-OVA) given by intravaginal (ivag) route to induce genital OVA-specific CTLs in mice. Using adoptive transfer models, we demonstrate that ivag application of CTB-OVA activates OVA-specific IFN-gamma-producing CD4 and CD8 T cells in draining lymph nodes (DLN). Moreover, ivag CTB induces an expansion of IFN-gamma-secreting CD8+ T cells in DLN and genital mucosa and promotes Ab responses to OVA. In contrast, ivag administration of OVA alone or coadministered with CTB failed to induce such responses. Importantly, we demonstrate that ivag CTB-OVA generates OVA-specific CTLs in DLN and the genital mucosa. Furthermore, genital CD11b+ CD11c+ dendritic cells (DCs), but not CD8+ CD11c+ or CD11c- APCs, present MHC class I epitopes acquired after ivag CTB-OVA, suggesting a critical role of this DC subset in the priming of genital CTLs. Inhibition studies indicate that the presentation of OVA MHC class I epitopes by DCs conditioned with CTB-OVA involves a proteasome-dependent and chloroquine-sensitive mechanism. These results demonstrate that CTB is an efficient adjuvant-delivery system for DC-mediated induction of genital CTL responses and may have implications for the design of vaccines against sexually transmitted infections.     

Tolerance and phytoaccumulation of Chromium by three Azolla species

Azolla, an aquatic fern is ideal candidate for exploitation in constructed wetlands for treating metal-contaminated wastewaters. This study demonstrates the potential of Azolla spp. namely A. microphylla, A. pinnata and A.␣filiculoides to tolerate Cr ions in the growth environment and bioconcentrate them. These species could grow in presence of up to 10 μg ml⁻¹ Cr and showed biomass production 30–70% as compared to controls. Nitrogenase activity was not affected at 1–5 μg ml⁻¹ but at higher concentrations it diminished. There was no growth at higher concentrations of chromium. However, the necrosed biomass harvested from treatments containing higher concentrations of chromium, accumulated Cr to the levels 5000–15,000 μg g⁻¹. At increased levels of Cr, the metal was accumulated in higher amount in dry biomass. Bioconcentration Factor (BCF) ranged between 243 and 4617 for the three species. A. microphylla showed highest bioconcentration potential. Thus, these Azolla spp. can be exploited for treatment of tannery and other Cr contaminated wastewaters.     

Biosurfactant production by Pseudomonas sp. and its role in aqueous phase partitioning and biodegradation of chlorpyrifos

Aim:  To study the effect of biosurfactant on aqueous phase solubility and biodegradation of chlorpyrifos.
Methods and Results:  A Pseudomonas sp. (ChlD), isolated from agricultural soil by enrichment culture technique in the presence of chlorpyrifos, was capable of producing biosurfactant (rhamnolipids) and degrading chlorpyrifos (0·01 g l⁻¹). The partially purified rhamnolipid biosurfactant preparation, having a CMC of 0·2 g l⁻¹, was evaluated for its ability to enhance aqueous phase partitioning and degradation of chlorpyrifos (0·01 g l⁻¹) by ChlD strain. The best degradation efficiency was observed at 0·1 g l⁻¹ supplement of biosurfactant, as validated by GC and HPLC studies.
Conclusion:  The addition of biosurfactant at 0·1 g l⁻¹ resulted in more than 98% degradation of chlorpyrifos when compared to 84% in the absence of biosurfactant after 120-h incubation.
Significance and Impact of the Study:  This first report, to the best of our knowledge, on enhanced degradation of chlorpyrifos in the presence of biosurfactant(s), would help in developing bioremediation protocols to counter accumulation of organophosphates to toxic/carcinogenic levels in environment.     

9个水稻栽培种和1个水稻组培种对稻螟赤眼蜂和赤眼卵蜂的互利作用（英文）

采用培养皿法对营养生长期和开花期的9个水稻栽培种（Pusa Sugandh-2, Pusa Basmati-1, Pusa-2511, Pusa Basmati-370, Pusa-1077, Karnal Local, PRR-78, Jaya, Pusa-1238）和1个组培种（Culture No.34）的正己烷提取物进行了生测,以调查它们对稻螟赤眼蜂Trichogramma japonicum Ashmead和赤眼卵蜂Trichogramma chilonis (Ishii)平均寄生活性指数（PAI）和平均寄生百分率的影响。将不同水稻品种的正己烷提取物进行气相 液相色谱,来测定饱和碳氢化合物。其中,营养生长期的Pusa Sugandh-2叶片提取物激发两种寄生蜂产生最大的反应,平均寄生率最大。而开花期的Pusa Basmati-1使两种寄生蜂的平均寄生率最高。对营养生长阶段的叶片提取物进行的气相 液相色谱分析表明：Pusa Sugandh-2 含有25个碳原子(C25) 和29个碳原子 (C29)的2种化合物。对开花期的叶片提取物进行的气相 液相色谱分析也表明：Basmati-1 含有25个碳原子(C25)、26个碳原子(C26)和29个碳原子 (C29)的3种化合物,可激发寄生蜂产生最大的反应     

Immunogenicity and protective efficacy of GroEL (hsp60) of Streptococcus pneumoniae against lethal infection in mice

The present study was carried out to evaluate the immunogenicity and protective efficacy of GroEL (hsp60) of Streptococcus pneumoniae , by expressing full length GroEL in heterologous host Escherichia coli BL21(DE3). PCR-amplified groEL was ligated in pQE 30 expression vector and subsequently transformed in E. coli DH5α strains. Cloning of groEL was confirmed by double digestion, followed by DNA sequencing. The His-tag containing recombinant GroEL was purified by Ni-NTA affinity chromatography. To determine the immunogenicity of GroEL, the mice were immunized by injecting 40 μg GroEL protein per mouse intraperitoneally. The results showed a significant increase in antibody titre and lymphocyte proliferation in animals immunized with GroEL as compared with control. Further, there was an appreciable increase in interleukin-2 (IL-2) and IL-4 production in lymphocytes isolated from immunized mice as compared with control. To determine the efficacy of GroEL in eliciting protection, the mice were challenged with the lethal dose of S. pneumoniae A66 type 3 capsular strain intranasally after the seventh day of the last immunization. In the GroEL-immunized mice the onset of death was insignificantly delayed and all the mice died by the seventh day postinfection.     

Measuring Blood Pressure in Mice using Volume Pressure Recording, a Tail-cuff Method

The CODA 8-Channel High Throughput Non-Invasive Blood Pressure system measures the blood pressure in up to 8 mice or rats simultaneously. The CODA tail-cuff system uses Volume Pressure Recording (VPR) to measure the blood pressure by determining the tail blood volume. A specially designed differential pressure transducer and an occlusion tail-cuff measure the total blood volume in the tail without the need to obtain the individual pulse signal. Special attention is afforded to the length of the occlusion cuff in order to derive the most accurate blood pressure readings. VPR can easily obtain readings on dark-skinned rodents, such as C57BL6 mice and is MRI compatible. The CODA system provides you with measurements of six (6) different blood pressure parameters; systolic and diastolic blood pressure, heart rate, mean blood pressure, tail blood flow, and tail blood volume. Measurements can be made on either awake or anesthetized mice or rats. The CODA system includes a controller, laptop computer, software, cuffs, animal holders, infrared warming pads, and an infrared thermometer. There are seven different holder sizes for mice as small as 8 grams to rats as large as 900 grams.Open in a separate windowClick here to view.^{(51M, flv)}     

Structural transition from dimeric to tetrameric i‐motif,caused by the presence of TAA at the 3′‐end of human telomeric C‐rich sequence

Widely dispersed in genomic DNA, the tandem C‐rich repetitive stretches may fold below physiological pH, into i‐motif structures, stabilized by C·C⁺ pairing. Herein, structural status of a 9‐mer stretch d(CCCTAACCC), [the truncated double repeat of human telomeric sequence], and its extended version, comprising of additional ? TAA segment at the 3′‐end, representing the complete double repeat d(CCCTAACCCTAA), has been investigated. The pH dependent monophasic UV‐melting, Gel and CD data suggested that while the truncated version adopts a bimolecular i‐motif structure, its complete double repeat (12‐mer) sequence exists in two (bimolecular and tetramolecular) forms. A model is proposed for the tetramolecular i‐motif with conventional C · C⁺ base pairs, additionally stabilized by asymmetric A · A base pairs at the ?3′ TAA flanking ends and Watson–Crick A · T hydrogen bonding between intervening bases on antiparallel strands. Expanding the known topologies of DNA i‐motifs, such atypical geometries of i‐motifs may have implications in their recognition by proteins. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 150–160, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com