Rapid detection and characterization of Chikungunya virus by RT-PCR in febrile patients from Kerala, India

There has been a resurgence and prevalence of fever with symptoms of Chikungunya (CHIK) and increased death toll in Kerala, the southern-most state of India. The objective of this study was to develop a rapid detection method to determine the presence of CHIK- virus in the serum samples collected from febrile patients in Kerala, India. Serum specimens were analyzed for CHIK viral RNA by RT-PCR using primers specific for nsP1 and E1 genes. Five out of twenty clinical samples were positive for CHIK virus. The partial sequences of the E1 and nsP1 genes of the strain, IndKL01 were highly similar to the Reunion strains and the recently isolated Indian strains. A novel substitution, A148V, was detected in the E1 gene of the isolate, IndKL02. The detection procedure used in this study was simple, sensitive and rapid (less than 4 hr). This result suggests that CHIK viruses similar to the Reunion strains, which had resulted in high morbidity and mortality rates, may have caused the recent Chikungunya outbreak in India. The effect of the variant, E1-A148V, in the virulence and the rate of transmission of the virus deserves further investigation.     

Architecture and applications for an All-FPGA parallel computer

The Reconfigurable Computing Cluster (RCC) project has been investigating unconventional architectures for high end computing using a cluster of FPGA devices connected by a high-speed, custom network. Most applications use the FPGAs to realize an embedded System-on-a-Chip (SoC) design augmented with application-specific accelerators to form a message-passing parallel computer. Other applications take a single accelerator core and tessellate the core across all of the devices, treating them like a large virtual FPGA. The experimental hardware has also been used for basic computer research by emulating novel architectures. This article discusses the genesis of the over-arching project, summarizes results of individual investigations that have been completed, and how this approach may prove useful in the investigation of future Exascale systems.     

Amphotericin B inhibits entry of Leishmania donovani into primary macrophages

Visceral leishmaniasis is a vector-borne disease caused by an obligate intra-macrophage protozoan parasite Leishmania donovani. The molecular mechanisms involved in internalization of Leishmania are still poorly understood. Amphotericin B and its formulations are considered as the best existing drugs against visceral leishmaniasis and are being increasingly used. The reason for its antileishmanial activity is believed to be its ability to bind ergosterol found in parasite membranes. In case of in vivo amphotericin B treatment, both host macrophages and parasites are exposed to amphotericin B. The effect of amphotericin B treatment could therefore be due to a combination of its interaction with both sterols i.e., ergosterol of Leishmania and cholesterol of host macrophages. We report here that cholesterol complexation by amphotericin B markedly inhibits binding of L. donovani promastigotes to macrophages. These results represent one of the first reports on the effect of amphotericin B on the binding of Leishmania parasites to host macrophages. Importantly, these results offer the possibility of reevaluating the mechanism behind the effectiveness of current therapeutic strategies that employ sterol-complexing agents such as amphotericin B to treat leishmaniasis.     

Process design and optimization of bioethanol production from cassava bagasse using statistical design and genetic algorithm

Abstract

Bioethanol production from agro-industrial residues is gaining attention because of the limited production of starch grains and sugarcane, and food–fuel conflict. The aim of the present study is to maximize the bioethanol production using cassava bagasse as a feedstock. Enzymatic liquefaction, by α-amylase, followed by simultaneous saccharification and fermentation (SSF), using glucoamylase and Zymomonas mobilis MTCC 2427, was investigated for bioethanol production from cassava bagasse. The factors influencing ethanol production process were identified and screened for significant factors using Plackett–Burman design. The significant factors (cassava bagasse concentration (10–50?g/L), concentration of α-amylase (5–25% (v/v), and temperature of fermentation (27–37?°C)) were optimized by employing Box–Behnken design and genetic algorithm. The maximum ethanol concentrations of 25.594?g/L and 25.910?g/L were obtained from Box–Behnken design and genetic algorithm, respectively, under optimum conditions. Thus, the study provides valuable insights in utilizing the cost-effective industrial residue, cassava bagasse, for the bioethanol production.     

MODELING AND OPTIMIZATION OF GLUTAMIC ACID PRODUCTION USING MIXED CULTURE OF Corynebacterium glutamicum NCIM2168 AND Pseudomonas reptilivora NCIM2598

In this study, a hybrid system of response surface methodology followed by genetic algorithm has been adopted to optimize the production medium for L-glutamic acid fermentation with mixed cultures of Corynebacterium glutamicum and Pseudomonas reptilovora. The optimal combination of media components for maximal production of L-glutamic acid was found to be 49.99 g L^?1 of glucose, 10 g L^?1 of urea, 18.06% (v/v) of salt solution, and 4.99% (v/v) of inoculum size. The experimental glutamic acid yield at optimum condition was 19.69 g L^?1, which coincided well to the value predicted by the model (19.61 g L^?1). Using this methodology, a nonlinear regression model was developed for the glutamic acid production. The model was validated statistically and the determination coefficient (R ²) was found to be 0.99.     

The function of G-protein coupled receptors and membrane cholesterol: specific or general interaction?

Cholesterol is an essential component of eukaryotic membranes and plays a crucial role in membrane organization, dynamics and function. The G-protein coupled receptors (GPCRs) are the largest class of molecules involved in signal transduction across membranes and constitute ~1–2% of the human genome. GPCRs have emerged as major targets for the development of novel drug candidates in all clinical areas due to their involvement in the generation of multitude of cellular responses. Membrane cholesterol has been reported to have a modulatory role in the function of a number of GPCRs. This effect could either be due to specific molecular interaction between cholesterol and GPCR, or due to alterations in the membrane physical properties induced by cholesterol. Alternatively, membrane cholesterol could modulate receptor function by occupying the ‘nonannular’ sites around the receptor. In this review, we have highlighted the nature of cholesterol dependence of GPCR function taking a few known examples.     

Evaluation of the potential of cassava-based residues for biofuels production

Cassava is the third significant source of calories after rice and maize in tropical countries. The annual production of cassava crop is approximately 550 million metric tons (MMT) which generates about 350 MMT of cassava solid residues, including peel, bagasse, stem, rhizome, and leaves. Cassava peel, bagasse, stem, and rhizome can be exploited for solid, liquid and gaseous biofuels production. Biofuels production from cassava starch started in the 1970s and researchers are now extensively studying cassava residues like peel, bagasse, stem, rhizome, and leaves to unravel their applications in biofuels production. However, there are technical and economic challenges to overcome the problems existing in the production of biofuels from cassava-based residues. This review provides a comprehensive summary of the techniques used for biofuels production from various cassava-based residues.     

Differential effects of cholesterol and its immediate biosynthetic precursors on membrane organization

Cholesterol is the most representative sterol present in vertebrate membranes and is the end product of the long and multistep sterol biosynthetic pathway. 7-Dehydrocholesterol (7-DHC) and desmosterol are the immediate biosynthetic precursors of cholesterol in the Kandutsch-Russell and Bloch pathway. In this article, we have monitored the effect of cholesterol and its two immediate biosynthetic precursors on biophysical and dynamic properties of fluid and gel phase membranes. Toward this goal, we have used fluorescent membrane probes, DPH and TMA-DPH, and the hydrophobic probe, pyrene. Our results using these probes show that although both 7-DHC and desmosterol differ with cholesterol in one double bond, they exhibit differential effects on membrane organization and dynamics. Importantly, we show that the effect of cholesterol and desmosterol on membrane organization and dynamics is similar in most cases, while 7-DHC has a considerably different effect. This demonstrates that the position of the double bond in sterols is an important determinant in maintaining membrane order and dynamics. These results assume relevance since the accumulation of cholesterol precursors have been reported to result in severe pathological conditions.     

Signaling by the human serotonin1A receptor is impaired in cellular model of Smith-Lemli-Opitz Syndrome

The Smith-Lemli-Opitz Syndrome (SLOS) is a congenital and developmental malformation syndrome associated with defective cholesterol biosynthesis. SLOS is clinically diagnosed by reduced plasma levels of cholesterol along with elevated levels of 7-dehydrocholesterol (and its positional isomer 8-dehydrocholesterol) and the ratio of their concentrations to that of cholesterol. Since SLOS is associated with neurological deformities and malfunction, exploring the function of neuronal receptors and their interaction with membrane cholesterol under these conditions assumes significance. We have earlier shown the requirement of membrane cholesterol for the ligand binding function of an important neurotransmitter G-protein coupled receptor, the serotonin_1A receptor. In the present work, we have generated a cellular model of SLOS using CHO cells stably expressing the human serotonin_1A receptor. This was achieved by metabolically inhibiting the biosynthesis of cholesterol, utilizing a specific inhibitor (AY 9944) of the enzyme required in the final step of cholesterol biosynthesis. We utilized this cellular model to monitor the function of the human serotonin_1A receptor under SLOS-like condition. Our results show that ligand binding activity, G-protein coupling and downstream signaling of serotonin_1A receptors are impaired in SLOS-like condition, although the membrane receptor level does not exhibit any reduction. Importantly, metabolic replenishment of cholesterol using serum partially restored the ligand binding activity of the serotonin_1A receptor. These results are potentially useful in developing strategies for the future treatment of the disease since intake of dietary cholesterol is the only feasible treatment for SLOS patients.