Treatment of W. bancrofti (Wb) in HIV/Wb Coinfections in South India

BackgroundThe disease course of human immunodeficiency virus (HIV) is often altered by existing or newly acquired coincident infections.Conclusions/SignificanceWe were unable to find a significant effect of W. bancrofti infection or its treatment on HIV clinical course or surrogate markers of HIV disease progression though we recognized that our study was limited by the smaller than predicted sample size and by the use of ART in half of the patients. Treatment of W. bancrofti coinfection in HIV positive subjects (as is usual in mass drug administration campaigns) did not represent an increased risk to the subjects, and should therefore be considered for PLWHA living in W. bancrofti endemic areas.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00344279","term_id":"NCT00344279"}}NCT00344279     

Prion Protein Does Not Confer Resistance to Hippocampus-Derived Zpl Cells against the Toxic Effects of Cu2+, Mn2+, Zn2+ and Co2+ Not Supporting a General Protective Role for PrP in Transition Metal Induced Toxicity

The interactions of transition metals with the prion protein (PrP) are well-documented and characterized, however, there is no consensus on their role in either the physiology of PrP or PrP-related neurodegenerative disorders. PrP has been reported to protect cells from the toxic stimuli of metals. By employing a cell viability assay, we examined the effects of various concentrations of Cu²⁺, Zn²⁺, Mn²⁺, and Co²⁺ on Zpl (Prnp ^-/-) and ZW (Prnp ^+/+) hippocampus-derived mouse neuronal cells. Prnp ^-/- Zpl cells were more sensitive to all four metals than PrP-expressing Zw cells. However, when we introduced PrP or only the empty vector into Zpl cells, we could not discern any protective effect associated with the presence of PrP. This observation was further corroborated when assessing the toxic effect of metals by propidium-iodide staining and fluorescence activated cell sorting analysis. Thus, our results on this mouse cell culture model do not seem to support a strong protective role for PrP against transition metal toxicity and also emphasize the necessity of extreme care when comparing cells derived from PrP knock-out and wild type mice.     

Tumor T1 Relaxation Time for Assessing Response to Bevacizumab Anti-Angiogenic Therapy in a Mouse Ovarian Cancer Model

Purpose

To assess whether T₁ relaxation time of tumors may be used to assess response to bevacizumab anti-angiogenic therapy. Procedures: 12 female nude mice bearing subcutaneous SKOV3ip1-LC ovarian tumors were administered bevacizumab (6.25ug/g, n=6) or PBS (control, n=6) therapy twice a week for two weeks. T₁ maps of tumors were generated before, two days, and 2 weeks after initiating therapy. Tumor weight was assessed by MR and at necropsy. Histology for microvessel density, proliferation, and apoptosis was performed.

Results

Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy. Tumor T₁ relaxation times increased in bevacizumab treated mice 2 days and 2 weeks after initiating therapy (p<.05, n=6). Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.

Conclusions

Findings suggest that increased tumor T₁ relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.     

Molecular characterization and expression analysis of BmNOX in two strains of Bombyx mori with contrasting viral resistance phenotype

We recently documented the identification of a 26.5 kDa protein named BmNox in the gut fluid of Nistari strain of Bombyx mori, which possessed antiviral activity against BmNPV in vitro. In this report, we report the characterization of the full‐length gene encoding BmNOX and the levels of expression of this gene in select tissues of silkworm larvae from a BmNPV‐susceptible and a BmNPV‐resistant strain to the defense capability in Bombyx mori larvae challenged with BmNPV. We also evaluated the BmNox expression in various stages of larval life of a resistant and a susceptible strain of Bombyx mori selected from among a panel of strains of silkworm. Nistari, a multivoltine strain of silkworm, expressed BmNOX during all five larval stages, and were highly resistant to BmNPV infection. In sharp contrast, CSR₂, a bivoltine strain, showed weaker expression of BmNOX in the anterior midgut in larval life and was highly susceptible to BmNPV infection. BmNOX is a secretory protein with dual expression in gut fluid and mid gut tissue. BmNOX is expressed heavily in the posterior mid gut, with weaker expression in the fore‐ and mid‐gut regions. © 2010 Wiley Periodicals, Inc.     

The glabra1 Mutation Affects Cuticle Formation and Plant Responses to Microbes

Systemic acquired resistance (SAR) is a form of defense that provides resistance against a broad spectrum of pathogens in plants. Previous work indicates a role for plastidial glycerolipid biosynthesis in SAR. Specifically, mutations in FATTY ACID DESATURASE7 (FAD7), which lead to reduced trienoic fatty acid levels and compromised plastidial lipid biosynthesis, have been associated with defective SAR. We show that the defective SAR in Arabidopsis (Arabidopsis thaliana) fad7-1 plants is not associated with a mutation in FAD7 but rather with a second-site mutation in GLABRA1 (GL1), a gene well known for its role in trichome formation. The compromised SAR in gl1 plants is associated with impairment in their cuticles. Furthermore, mutations in two other components of trichome development, GL3 and TRANSPARENT TESTA GLABRA1, also impaired cuticle development and SAR. This suggests an overlap in the biochemical pathways leading to cuticle and trichome development. Interestingly, exogenous application of gibberellic acid (GA) not only enhanced SAR in wild-type plants but also restored SAR in gl1 plants. In contrast to GA, the defense phytohoromes salicylic acid and jasmonic acid were unable to restore SAR in gl1 plants. GA application increased levels of cuticular components but not trichome formation on gl1 plants, thus implicating cuticle, but not trichomes, as an important component of SAR. Our findings question the prudence of using mutant backgrounds for genetic screens and underscore a need to reevaluate phenotypes previously studied in the gl1 background.Plants have evolved a large array of defense mechanisms to resist infection by pathogens. Upon recognition, the host plant initiates one or more signal transduction pathways that activate various plant defenses and thereby prevent pathogen colonization. In many cases, resistance is associated with increased expression of defense genes, including the pathogenesis-related (PR) genes and the accumulation of salicylic acid (SA) in the inoculated leaf. Induction of these responses is accompanied by localized cell death at the site of pathogen entry, which can often restrict the spread of pathogen to cells within and immediately surrounding the lesions. This phenomenon, known as the hypersensitive response, is one of the earliest visible manifestations of induced defense responses and resembles programmed cell death in animals (Dangl et al., 1996; Gray, 2002; Glazebrook, 2005; Kachroo and Kachroo, 2006). Concurrent with hypersensitive response development, defense reactions are triggered in sites both local and distal from the primary infection. This phenomenon, known as systemic acquired resistance (SAR), is accompanied by a local and systemic increase in SA and jasmonic acid (JA) and a concomitant up-regulation of a large set of defense genes (Durrant and Dong, 2004; Truman et al., 2007; Vlot et al., 2009).SAR involves the generation of a mobile signal in the primary leaves that, upon translocation to the distal tissues, activates defense responses resulting in broad-spectrum resistance. The production of the mobile signal takes places within 3 to 6 h of avirulent pathogen inoculation in the primary leaves (Smith-Becker et al., 1998), and the inoculated leaf must remain attached for at least 4 h after inoculation for immunity to be induced in the systemic tissues (Rasmussen et al., 1991). Mutations compromising SA synthesis or impairing SA, JA, or auxin signaling abolish SAR (Durrant and Dong, 2004; Truman et al., 2007, 2010). SAR is also dependent on the SALICYLIC ACID-BINDING PROTEIN2 (SABP2)-catalyzed conversion of methyl SA to SA in the distal tissues (Kumar and Klessig, 2003). Recent studies have suggested that methyl SA is the mobile signal required to initiate SAR in distal tissues in tobacco (Nicotiana tabacum; Park et al., 2007) and Arabidopsis (Arabidopsis thaliana; Liu et al., 2010), although another group reported a disparity in their findings related to the role of methyl SA in Arabidopsis (Attaran et al., 2009). Notably, the time point of requirement of SABP2 activity (between 48 and 72 h post inoculation; Park et al., 2009) does not coincide with the early generation and/or translocation of the mobile signal into distal tissues (within 6 h post inoculation).The mutations acyl carrier protein4 (acp4), long-chain acyl-CoA synthetase2 (lacs2), and lacs9, which are impaired in fatty acid (FA)/lipid flux (Schnurr et al., 2004; Xia et al., 2009), also compromise SAR (Xia et al., 2009). Detailed characterization has shown that the SAR defect in acp4, lacs2, and lacs9 mutants correlates with their defective cuticles. Analysis of the SAR response in acp4 plants has shown that these plants can generate the mobile signal required for inducing SAR but are unable to respond to it. It is likely that the defective cuticle in these plants impairs their ability to perceive the SAR signal, because mechanical abrasion of cuticles disrupts SAR in wild-type plants (Xia et al., 2009). This SAR-disruptive effect of cuticle abrasion is highly specific, because it does not alter local defenses and hinders SAR only during the time frame during which the mobile signal is translocated to distal tissues.SAR is also compromised in plants that contain a mutation in glycerol-3-phosphate dehydrogenase (Nandi et al., 2004). The glycerol-3-phosphate dehydrogenase (GLY1) reduces dihydroxyacetone phosphate to generate glycerol-3-phosphate, an obligatory component and precursor for the biosynthesis of all plant glycerolipids. Consequently, a mutation in GLY1 results in reduced carbon flux through the prokaryotic pathway of lipid biosynthesis, which leads to a reduction in the hexadecatrienoic (16:3) FAs (Miquel et al., 1998; Kachroo et al., 2004). Carbon flux and SAR are also impaired in plants containing mutations in FATTY ACID DESATURASE7 (FAD7; Chaturvedi et al., 2008). The FAD7 enzyme desaturates 16:2 and 18:2 FA species present on plastidial lipids to 16:3 and 18:3, respectively. Consequently, the fad7 mutant plants accumulate significantly reduced levels of trienoic FAs (16:3 and 18:3). Compromised SAR in mutants affected in certain plastidial FA/lipid pathways has prompted the suggestion that plastidial FA/lipids participate in SAR (Chaturvedi et al., 2008). Such a tempting conclusion is also favored by the fact that SAR requires the DIR1-encoded nonspecific lipid transfer protein, which is required for the generation and/or translocation of the mobile signal (Maldonado et al., 2002). In addition, azelaic acid, a dicarboxylic acid, was recently shown to prime SA biosynthesis and thereby SAR (Jung et al., 2009). The fact that azelaic acid is derived from oleic acid, a FA well known for its role in defense (Kachroo et al., 2003, 2004, 2005, 2007, 2008; Chandra-Shekara et al., 2007; Jiang et al., 2009; Venugopal et al., 2009; Xia et al., 2009), further suggests that FA/lipids might participate in SAR.This study was undertaken to reexamine the role of the FA/lipid pathways in SAR and to determine the nature of the FA/lipid species mediating SAR in fad7-1 plants. Our results show that impaired FA/lipid flux is not associated with compromised SAR in fad7-1 plants but, rather, with an abnormal cuticle, which is the result of a nonallelic mutation in the GLABRA1 (GL1) gene. Besides GL1, other mutations affecting trichome formation also compromised cuticle and thereby SAR. A compensatory effect of exogenous GA on gl1 plants suggests that GA might participate in resistance to bacterial pathogens by restoring cuticle formation.     

Fungal biosynthesis of endochitinase and chitobiase in solid state fermentation and their application for the production of N-acetyl-D-glucosamine from colloidal chitin

The present study was directed to the production of N-acetyl-D-glucosamine using endochitinase and chitobiase from fungal cultures in solid culturing. Fifteen fungal strains were evaluated for endochitinase and chitobiase production under solid-state fermentation using agro-industrial residues, of which Penicillium aculeatum NRRL 2129 showed maximum endochitinase activity whereas Trichoderma harzianum TUBF 927 showed maximum chitobiase activity. Eleven substrates, alone and in combination with chitin, were evaluated for the enzyme production. Optimization of physico-chemical parameters such as incubation period and initial moisture content, and nutritional parameters such as chitin source, inorganic and organic nitrogen sources, were carried out. Optimization resulted in more than 3-fold increase in endochitinase production (from 3.5 to 12.53 U/g dry weight of substrate) and about 1.5-fold increase in chitobiase production (from 1.6 to 2.25 U/g dry weight of substrate). Studies on the degradation of colloidal chitin to N-acetyl-D-glucosamine showed improved efficiency when endochitinase and chitobiase were used in combination.     

Implementation of a k/k(0) method to identify long-range structure in transition states during conformational folding/unfolding of proteins

A previously introduced kinetic-rate constant (k/k(0)) method, where k and k(0) are the folding (unfolding) rate constants in the mutant and the wild-type forms, respectively, of a protein, has been applied to obtain qualitative information about structure in the transition state ensemble (TSE) of bovine pancreatic ribonuclease A (RNase A), which contains four native disulfide bonds. The method compares the folding (unfolding) kinetics of RNase A, with and without a covalent crosslink and tests whether the crosslinked residues are associated in the folding (unfolding) transition state (TS) of the noncrosslinked version. To confirm that the fifth disulfide bond has not introduced a significant structural perturbation, we solved the crystal structure of the V43C-R85C mutant to 1.6 A resolution. Our findings suggest that residues Val43 and Arg85 are not associated, and that residues Ala4 and Val118 may form nonnative contacts, in the folding (unfolding) TSE of RNase A.     

Prediction of enzymes and non-enzymes from protein sequences based on sequence derived features and PSSM matrix using artificial neural network

The problem of predicting the enzymes and non-enzymes from the protein sequence information is still an open problem in bioinformatics. It is further becoming more important as the number of sequenced information grows exponentially over time. We describe a novel approach for predicting the enzymes and non-enzymes from its amino-acid sequence using artificial neural network (ANN). Using 61 sequence derived features alone we have been able to achieve 79 percent correct prediction of enzymes/non-enzymes (in the set of 660 proteins). For the complete set of 61 parameters using 5-fold cross-validated classification, ANN model reveal a superior model (accuracy = 78.79 plus or minus 6.86 percent, Q(pred) = 74.734 plus or minus 17.08 percent, sensitivity = 84.48 plus or minus 6.73 percent, specificity = 77.13 plus or minus 13.39 percent). The second module of ANN is based on PSSM matrix. Using the same 5-fold cross-validation set, this ANN model predicts enzymes/non-enzymes with more accuracy (accuracy = 80.37 plus or minus 6.59 percent, Q(pred) = 67.466 plus or minus 12.41 percent, sensitivity = 0.9070 plus or minus 3.37 percent, specificity = 74.66 plus or minus 7.17 percent).