High-resolution crystal structure of FKBP12 from Aedes aegypti

Dengue is one of the most infectious viral diseases prevalent mainly in tropical countries. The virus is transmitted by Aedes species of mosquito, primarily Aedes aegypti. Dengue remains a challenging drug target for years as the virus eludes the immune responses. Currently, no vaccines or antiviral drugs are available for dengue prevention. Previous studies suggested that the immunosuppressive drug FK506 shows antimalarial activity, and its molecular target, FK506‐binding protein (FKBP), was identified in the Plasmodium parasite. Likewise, a FKBP family protein has been identified in A. aegypti (AaFKBP12) in which AaFKBP12 is assumed to play a similar role in its life cycle. FKBPs belong to a highly conserved class of proteins and are considered as an attractive pharmacological target. Herein, we present a high‐resolution crystal structure of AaFKBP12 at 1.3 Å resolution and discuss its structural features throwing light in facilitating the design of potential antagonists against the dengue‐transmitting mosquito.     

Synthesis and preliminary screening of novel N-{2-[4-(substituted)piperazin-1-yl]-2-oxoethyl}acetamides as potential atypical antipsychotic agents

A series of N-{2-[4-(substituted)piperazin-1-yl]-2-oxoethyl}acetamides were synthesized as prospective novel atypical antipsychotic agents. Microwave irradiation of acetyl glycine (I) with substituted piperazines in the presence of DCC in DMF for about 3-5 min gave the titled compounds (P:1-7). All the synthesized compounds were screened for their in vivo pharmacological activity in Swiss albino mice. D(2) antagonism studies were performed using the climbing mouse assay model and 5-HT(2A) antagonism studies were performed using quipazine induced head twitches in mice. Among the synthesized compounds P4 was found to be the most active compound.     

Genetic differentiation among Sri Lankan traditional rice (Oryza sativa) varieties and wild rice species by AFLP markers

Traditional rice varieties are one important component of the biodiversity of Sri Lanka. However, no proper studies have been performed on genetic diversity of the Sri Lankan traditional rice varieties used in our breeding programs. In the present study, the genetic diversity of 46 traditional rice (Oryza sativa) varieties and 5 wild rice species is assesed using Amplified Fragment Length Polymorphism (AFLP) markers. Ten primer combinations generated a total of 784 fragments. Of these, 772 fragments were polymorphic (98.4%). UPGMA analysis based on Jaccard's similarity separated the accessions into four major clusters. A cophenetic correlation with r=0.786 strongly supported the clustering pattern of UPGMA dendrogram. A principal coordinate analysis (PCoA) also confirmed the UPGMA clusters. Accessions referred to the same cluster showed similar morphological characteristics (e.g. height, grain colour etc.) while accessions which are known to be morphologically distinct appeared genetically separated. In addition, the clustering pattern distinctly separated lowland and upland rice varieties. This genetic diversity assessment at the molecular level provides reliable information for selection of germplasm in the development of new rice varieties and in conservation of traditional rice genetic resources.     

Mevalonate-metabolizing enzymes in Arachis hypogaea

Summary The activities of the mevalonate metabolizing enzymes-HMG-CoA reductase, mevalonate kinase, mevalonate phosphokinase and mevalonate pyrophosphate decarboxylase -were assayed with the respective substrates in green seedlings of Arachis hypogaea. MVAPP decarboxylase is the rate-limiting step among these enzymes and is inhibited by phenolic acids. Its activity in the seedlings was found to decrease in the absence of light and on treatment with abscisic acid. These results suggest that regulation of isoprene pathway in groundnut seedlings may occur at the level of mevalonate decarboxylation.Abbreviations HMG CoA 3-hydroxy-3-methyl-glutaryl coenzyme A - MVA Mevalonate - MVAP Mevalonate-5-phosphate - MVAPP Mevalonate-5-pyrophosphate - DTT Dithiothreitol - ABA Abscisic Acid     

Going beyond Clustering in MD Trajectory Analysis: An Application to Villin Headpiece Folding

Recent advances in computing technology have enabled microsecond long all-atom molecular dynamics (MD) simulations of biological systems. Methods that can distill the salient features of such large trajectories are now urgently needed. Conventional clustering methods used to analyze MD trajectories suffer from various setbacks, namely (i) they are not data driven, (ii) they are unstable to noise and changes in cut-off parameters such as cluster radius and cluster number, and (iii) they do not reduce the dimensionality of the trajectories, and hence are unsuitable for finding collective coordinates. We advocate the application of principal component analysis (PCA) and a non-metric multidimensional scaling (nMDS) method to reduce MD trajectories and overcome the drawbacks of clustering. To illustrate the superiority of nMDS over other methods in reducing data and reproducing salient features, we analyze three complete villin headpiece folding trajectories. Our analysis suggests that the folding process of the villin headpiece is structurally heterogeneous.     

The eye does not see what the mind does not know: the bacterium in the worm

Symbiotic relationships underlie the evolutionary success of many different life forms. The filarial worms are long, slender nematode parasites that cause considerable pathology in large segments of the world's population. About 25 years ago, investigators first reported the presence of bacterial organisms living inside these parasitic worms. Recent molecular biological studies have indicated that these bacteria belong to the genus Wolbachia, members of which have been known to be associated with numerous species of insects. Elimination of the Wolbachia from the nematodes (by, for instance, treatment with broad spectrum antibiotics) results in profound disturbances in the physiology of the latter, including a complete block in reproduction. This observation, taken together with the fact that every individual worm examined to date contains Wolbachia, validates the classification of the latter as "endosymbionts." Many studies indicate that the Wolbachia may also play an important role in the pathology caused by the nematode worms, and that it might be possible to target therapy against the Wolbachia to treat the filarial disease. Intriguingly, the intense recent interest in Wolbachia is in complete contrast with the virtually complete indifference evoked by the original discovery of these organisms.     

The L3 to L4 molt of Brugia malayi: real time visualization by video microscopy

Brugia malayi and other filarial parasites have been studied in great detail, especially in the context of human disease. In common with other nematodes, these organisms molt 4 times in their life cycles, but details of this process have not been described. We have recently developed an in vitro culture system that supports the L3 to L4 molt at high efficiency. This has permitted us to visualize, for the first time, details of this molt using real-time video microscopy. Molting is preceded by a phase of altered motility during which the larva exhibits contractile, coiling movements. The earliest evidence of ecdysis is a clearing at one end, more frequently caudal, caused by the larva retracting from that end. A cleavage develops in the cuticle near the head end, forming a rostral cap, which is continuous with the pharyngeal cuticle. Simultaneously, it retracts out of the cuticle using coiling and writhing movements. This process takes 5 to 10 min. Finally, it retracts out of the cap and extrudes the pharyngeal cuticle. Detachment of the pharyngeal cuticle is the final event in the process and continues up to an hour after the rest of the cuticle has been shed.     

A novel anti-inflammatory role for simvastatin in inflammatory arthritis

3-Hydroxy-3-methylglutaryl-CoA reductase inhibitors (statins) exert favorable effects on lipoprotein metabolism, but may also possess anti-inflammatory properties. Therefore, we explored the activities of simvastatin, a lipophilic statin, in a Th1-driven model of murine inflammatory arthritis. We report in this study that simvastatin markedly inhibited not only developing but also clinically evident collagen-induced arthritis in doses that were unable to significantly alter cholesterol concentrations in vivo. Ex vivo analysis demonstrated significant suppression of collagen-specific Th1 humoral and cellular immune responses. Moreover, simvastatin reduced anti-CD3/anti-CD28 proliferation and IFN-gamma release from mononuclear cells derived from peripheral blood and synovial fluid. Proinflammatory cytokine production in vitro by T cell contact-activated macrophages was suppressed by simvastatin, suggesting that such observations have direct clinical relevance. These data clearly illustrate the therapeutic potential of statin-sensitive pathways in inflammatory arthritis.