Search

SARS-CoV-2 enters the host cell through the ACE2 receptor and replicates its genome using an RNA-Dependent RNA Polymerase (RDRP). The functional RDRP is released from pro-protein pp1ab by the proteolytic activity of Main protease (Mpro) which is encoded within the viral genome. Due to its vital role in proteolysis of viral polyprotein chains, it has become an attractive potential drug target. We employed a hierarchical virtual screening approach to identify small synthetic protease inhibitors. Statistically optimized molecular shape and color-based features (various functional groups) from co-crystal ligands were used to screen different databases through various scoring schemes. Then, the electrostatic complementarity of screened compounds was matched with the most active molecule to further reduce the hit molecules’ size. Finally, five hundred eighty-seven molecules were docked in Mpro catalytic binding site, out of which 29 common best hits were selected based on Glide and FRED scores. Five best-fitting compounds in complex with Mpro were subjected to MD simulations to analyze their structural stability and binding affinities with Mpro using MM/GB(PB)SA models. Modeling results suggest that identified hits can act as the lead compounds for designing better active Mpro inhibitors to enhance the chemical space to combat COVID-19. Communicated by Ramaswamy H. Sarma

Plant pathogens and parasites are a major threat to global food security. Plant parasitism has arisen four times independently within the phylum Nematoda, resulting in at least one parasite of every major food crop in the world. Some species within the most economically important order (Tylenchida) secrete proteins termed effectors into their host during infection to re-programme host development and immunity. The precise detail of how nematodes evolve new effectors is not clear. Here we reconstruct the evolutionary history of a novel effector gene family. We show that during the evolution of plant parasitism in the Tylenchida, the housekeeping glutathione synthetase (GS) gene was extensively replicated. New GS paralogues acquired multiple dorsal gland promoter elements, altered spatial expression to the secretory dorsal gland, altered temporal expression to primarily parasitic stages, and gained a signal peptide for secretion. The gene products are delivered into the host plant cell during infection, giving rise to “GS-like effectors”. Remarkably, by solving the structure of GS-like effectors we show that during this process they have also diversified in biochemical activity, and likely represent the founding members of a novel class of GS-like enzyme. Our results demonstrate the re-purposing of an endogenous housekeeping gene to form a family of effectors with modified functions. We anticipate that our discovery will be a blueprint to understand the evolution of other plant-parasitic nematode effectors, and the foundation to uncover a novel enzymatic function., Author summary Plants and their pathogens/parasites are locked in an evolutionary arms race, with considerable attention directed towards the specific functions of the parasites’ “weapons”: the effectors. While we are beginning to understand these functions, we have very little understanding of how plant parasitic nematodes have bolstered their effector repertoire. Here we provide an example of how plant parasites of global economic importance have populated their effector repertoire by the unprecedented duplication and subsequent re-deployment of the endogenous housekeeping gene, glutathione synthetase. We hypothesise that many aspects of the “weaponization” programme detailed here will be common to the genesis of other plant-parasitic nematode effectors. Given that parasitic nematodes deploy a battery of effectors, many arising from the adaptation of either endogenous genes or loci acquired by horizontal gene transfer, this paradigm will have substantial impact on the effort to understand and ultimately undermine devastating USDA and EPPO quarantine organisms.

Background and Objectives: Medico legal cases are essential component of medical practice and comprise most important constituent of emergencies. The reporting of such cases is imperative to recognize theirsocioeconomic burden on any country. The present study was conducted to scrutinize different categories of medico legal cases and characteristics of the victims at casualty department oftertiary care hospital Rawalpindi. The objective of the study was to find out the frequency ofvarious categories of medico legal cases and major characteristics ofvictims at tertiary care hospital, Rawalpindi. Methods: This was a cross-sectional study on 3105 registered cases in medico legal record of the casualty department of Benazir Bhutto hospital, Rawalpindi from January 2015 to December 2015. The hospital is located on the main road in densely populated central area of the city. The data wascollected on age, sex, month-wise distribution of various medico legal cases, weapon inflicting the injury, blunt trauma or physical assault, firearm injuries and road traffic accidents. The data thus obtained was analyzed using SPSS; observations were presented in tables and graphs. Results: Out of all 3105 registered medico legal cases, reported cases caused by Road Traffic Accident 1230 (40%) followed by blunt injury or physical assault 966 (32%) cases, 19% by sharp weapons, 5% by poisoning, and 4% by firearm injuries. In our study out of 3105 cases, almost three quarter of victims (73%) were below 30 years of age, with a decreasing frequency beyond this age, males were predominantly inflicted 2516(81%) as compared to females 589 (19%). The reported road traffic accidents cases from urban areas were high (74%) as compared to those from rural locality (37%). In cases of blunt trauma, sharp weapon injuries and firearm injuries, there was a huge preponderance of victims from rural areas (65%), (62%) and 61% respectively, with urban cases constituting less. Conclusion: Road traffic injuries are one of the foremost causes of medico legal cases followed by blunt trauma and sharp weapon injuries. The emerging medico legal cases are neglected epidemic in most of the developing countries comprising a considerable public health problem.

14 p.-1 tab.-8 fig. Shilpa Basavanna et alt., Bacterial pathogens need to acquire nutrients from the host, but for many nutrients their importance during infection remain poorly understood. We have investigated the importance of methionine acquisition and synthesis for Streptococcus pneumoniae growth and virulence using strains with gene deletions affecting a putative methionine ABC transporter lipoprotein (Sp_0149, metQ) and/or methionine biosynthesis enzymes (Sp_0585 - Sp_0586, metE and metF). Immunoblot analysis confirmed MetQ was a lipoprotein and present in all S. pneumoniae strains investigated. However, vaccination with MetQ did not prevent fatal S. pneumoniae infection in mice despite stimulating a strong specific IgG response. Tryptophan fluorescence spectroscopy and isothermal titration calorimetry demonstrated that MetQ has both a high affinity and specificity for L-methionine with a KD of ,25 nM, and a DmetQ strain had reduced uptake of C14-methionine. Growth of the DmetQ/DmetEF strain was greatly impaired in chemically defined medium containing low concentrations of methionine and in blood but was partially restored by addition of high concentrations of exogenous methionine. Mixed infection models showed no attenuation of the DmetQ, DmetEF and DmetQ/DmetEF strains in their ability to colonise the mouse nasopharnyx. In a mouse model of systemic infection although significant infection was established in all mice, there were reduced spleen bacterial CFU after infection with the DmetQ/DmetEF strain compared to the wild-type strain. These data demonstrate that Sp_0149 encodes a high affinity methionine ABC transporter lipoprotein and that Sp_0585 – Sp_0586 are likely to be required for methionine synthesis. Although Sp_0149 and Sp_0585-Sp_0586 make a contribution towards full virulence, neither was essential for S. pneumoniae survival during infection., This work was undertaken at UCLH/UCL, which received a proportion of funding from the Department of Health's NIHR Biomedical Research Centre's funding scheme, and was supported by the UCL Charities funding and grants from the British Lung Foundation (P05/3) and the Wellcome Trust (grant reference 076442).