145 research outputs found
Concurrent proinflammatory and apoptotic activity of a Helicobacter pylori protein (HP986) points to its role in chronic persistence.
No full textHelicobacter pylori induces cytokine mediated changes in gastroduodenal pathophysiology, wherein, the activated macrophages at the sub-mucosal space play a central role in mounting innate immune response against the antigens. The bacterium gains niche through persistent inflammation and local immune-suppression causing peptic ulcer disease or chronic gastritis; the latter being a significant risk factor for the development of gastric adenocarcinoma. What favors persistence of H. pylori in the gastric niches is not clearly understood. We report detailed characterization of a functionally unknown gene (HP986), which was detected in patient isolates associated with peptic ulcer and gastric carcinoma. Expression and purification of recombinant HP986 (rHP986) revealed a novel, ∼29 kDa protein in biologically active form which associates with significant levels of humoral immune responses in diseased individuals (p<0.001). Also, it induced significant levels of TNF-α and Interleukin-8 in cultured human macrophages concurrent to the translocation of nuclear transcription factor-κB (NF-κB). Further, the rHP986 induced apoptosis of cultured macrophages through a Fas mediated pathway. Dissection of the underlying signaling mechanism revealed that rHP986 induces both TNFR1 and Fas expression to lead to apoptosis. We further demonstrated interaction of HP986 with TNFR1 through computational and experimental approaches. Independent proinflammatory and apoptotic responses triggered by rHP986 as shown in this study point to its role, possibly as a survival strategy to gain niche through inflammation and to counter the activated macrophages to avoid clearance
Development of a risk score for prediction of poor treatment outcomes among patients with multidrug-resistant tuberculosis
No full textBackgroundTreatment outcomes among patients treated for multidrug-resistant tuberculosis (MDR-TB) are often sub-optimal. Therefore, the early prediction of poor treatment outcomes may be useful in patient care, especially for clinicians when they have the ability to make treatment decisions or offer counselling or additional support to patients. The aim of this study was to develop a simple clinical risk score to predict poor treatment outcomes in patients with MDR-TB, using routinely collected data from two large countries in geographically distinct regions.MethodsWe used MDR-TB data collected from Hunan Chest Hospital, China and Gondar University Hospital, Ethiopia. The data were divided into derivation (n = 343; 60%) and validation groups (n = 227; 40%). A poor treatment outcome was defined as treatment failure, lost to follow up or death. A risk score for poor treatment outcomes was derived using a Cox proportional hazard model in the derivation group. The model was then validated in the validation group.ResultsThe overall rate of poor treatment outcome was 39.5% (n = 225); 37.9% (n = 86) in the derivation group and 40.5% (n = 139) in the validation group. Three variables were identified as predictors of poor treatment outcomes, and each was assigned a number of points proportional to its regression coefficient. These predictors and their points were: 1) history of taking second-line TB treatment (2 points), 2) resistance to any fluoroquinolones (3 points), and 3) smear did not convert from positive to negative at two months (4 points). We summed these points to calculate the risk score for each patient; three risk groups were defined: low risk (0 to 2 points), medium risk (3 to 5 points), and high risk (6 to 9 points). In the derivation group, poor treatment outcomes were reported for these three groups as 14%, 27%, and 71%, respectively. The area under the receiver operating characteristic curve for the point system in the derivation group was 0.69 (95% CI 0.60 to 0.77) and was similar to that in the validation group (0.67; 95% CI 0.56 to 0.78; p = 0.82).ConclusionHistory of second-line TB treatment, resistance to any fluoroquinolones, and smear non-conversion at two months can be used to estimate the risk of poor treatment outcome in patients with MDR-TB with a moderate degree of accuracy (AUROC = 0.69).</div
Direct in-gel hybridization, without blotting, using nick-translated cloned DNA probe
No full textHybridization of DNA and RNA to labeled probes is central to molecular biology. A method is described here for hybridization of cloned DNA probes directly to DNA in agarose gels. This in-gel hybridization method has several advantages over conventional techniques using transfer to membranes. It is extremely rapid, highly sensitive, less expensive and particularly suited for high molecular weight genomic DNA analysis
Direct in-gel hybridization, without blotting, using nick-translated cloned DNA probe
No full textHybridization of DNA and RNA to labeled probes is central to molecular biology. A method is described here for hybridization of cloned DNA probes directly to DNA in agarose gels. This in-gel hybridization method has several advantages over conventional techniques using transfer to membranes. It is extremely rapid, highly sensitive, less expensive and particularly suited for high molecular weight genomic DNA analysis
A multicopy DNA sequence from Meconopsis simplicifolia discriminates between the different species of this endangered Himalayan poppy
No full textClones harboring multicopy DNA sequences were isolated on the basis of reverse genome hybridization to Meconopsis paniculata (Himalayan yellow poppy) DNA from a Sau3A partial genomic plasmid library of M. simplicifolia (Himalayan blue poppy). Restriction-endonuclease-dependent genetic polymorphism between five species of Meconopsis, M. aculeata, M. paniculata, M. simplicifolia, M. sinuata and M. villosa, belonging to geographically isolated populations, was evident in genomic DNA filter hybridizations when probed with a clone (pIMS10) isolated from this library. Pooled DNA from seedlings originating from plants of individual populations of M. paniculata, M. simplicifolia and M. villosa gave similar band patterns, with respect to a given enzyme, suggesting intra-population genetic homogeneity
Stable Isotopic Profiling of New Zealand Milk Powder
No full textTo contact the author please email: [email protected] thesis aims to develop a method to investigate the ability of bulk stable isotope and compound specific stable isotope tools to verify whether dietary feed fatty acids, bovine milk water and major bovine milk fatty acids are conveying biogeochemical attribution of their production region. This technique opens new insights into milk regional authenticity identification.
A multiple linear regression (MLR) model based on New Zealand climatic parameters was employed to verify its ability to predict δ2H values of rainfall from milk production regions. The MLR model showed promise to predict δ2H values of regional rain, yielding a high correlation to actual rain δ2H values (R2 = 0.73, P<0.05). Subsequently the model’s generated estimates of δ2H values for precipitation of the milk production regions, revealed strong geographical correlation between bulk δ2H values and δ2H values of some bovine milk short chain fatty acids (SCFA) to long chain fatty acid (LCFA).
In order to understand which of the major fatty acids in milk powder have the potential discrimination capability to allow the provenancing of milk powder, the δ2H value of C4:0 (butyric), C14:0 (myristic), C16:0 (palmitic) and the δ2H value of bulk milk which showed the highest correlation to regional rainfall was selected and analysed by employing multivariate statistics. The δ2H values of these compounds were found to be capable of explaining 91% of the isotopic variation. The hydrogen isotopic compositions of these milk compounds were able to separate milk production regions across New Zealand.
Subsequent exploration into finding the isotopic link between farm drinking water, grass/feed and milk, revealed that bovine milk bulk and fatty acid hydrogen isotope composition carries isotopic attributions both from feed and local water. However the influence of regional water on the 2H composition of the milk seems to be more pronounced.
The influence of seasonal variability on milk was examined on milk powder samples sourced from Norway. Results indicate that the milk powder fatty acid δ2H values and fatty acid concentrations were influenced by the time of sampling throughout the year, while the bulk milk δ2H and δ13C values remained relatively consistent across the sampling period. This may suggest a presence of a region specific isotope variability that may further be explored by comparing it with variability patterns of other regions.
A preliminary assessment on the potential of δ2H from milk fatty acids and bulk milk for determination of an adulterant (an unknown milk powder) in milk powder was investigated. Multivariate statistics were used to quantify the level of adulteration, which was able to resolve differences at a 5% level of adulterant in an authentic sample.
This thesis explores the potential application of stable isotope analysis to the authentication of the provenance of New Zealand milk. The approach utilized in this study could be adopted in other milk producing regions, or applied to other milk products such as infant formula for authentication purposes
The translation initiation factor, PeIF5B, from Pisum sativum displays chaperone activity
No full textWe earlier documented the structural and functional characterization of PeIF5B factor from Pisum sativum that shows strong homology to the universal translation initiation factor eIF5B (Rasheedi et al., 2007, 2010 and ). We now show that PeIF5B is an unusually thermo-stable protein resisting temperatures up to 95 °C. PeIF5B prevents thermal aggregation of heat labile proteins, such as citrate synthase (CS) and NdeI, under heat stress or chemical denaturation conditions and promotes their functional folding. It also prevents the aggregation of DTT induced insulin reduction. GTP appears to stimulate PeIF5B-mediated chaperone activity. In-vivo, PeIF5B over expression significantly enhances, the viability of Escherichia coli cells after heat stress (50 °C). These observations lead us to conclude that PeIF5B, in addition to its role in protein translation, has chaperone like activity and could be likely involved in protein folding and protection from stress
Iron acquisition, assimilation and regulation in mycobacteria
No full textIron is as crucial to the pathogen as it is to the host. The tuberculosis causing bacillus, Mycobacterium tuberculosis (M.tb), is an exceptionally efficient pathogen that has evolved proficient mechanisms to sequester iron from the host despite its thick mycolate-rich outer covering and a highly impermeable membrane of phagolysosome within which it persists inside an infected host macrophage. Further, both overindulgence and moderation of iron inside a host are a threat to mycobacterial persistence. While for removing iron from the host reservoirs, mycobacteria synthesize molecules that have several times higher affinity for iron than their host counterparts, they also synthesize molecules for efficient storage of excess iron. This is supported by tightly regulated iron dependent global gene expressions. In this review we discuss the various molecules and pathways evolved by mycobacteria for an efficient iron metabolism. We also discuss the less investigated players, like iron responsive proteins and iron responsive elements in mycobacteria, and highlight the lacunae in our current understanding of iron acquisition and utilization in mycobacteria with an ultimate aim to make iron metabolism as a possible anti-mycobacterial target
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