SCREENING OF PATHOGENIC AEROMONAS SPECIES FROM MARKETED FISH SAMPLES

Aeromonas spp. have received increasing attention as opportunistic as well as primary pathogens in humans, aquatic and terrestrial animals. Aeromonads are common contaminants in foods such as fish and other sea foods, raw and cooked meat, poultry, vegetables, milk and milk products. Factors contributing to virulence include toxins, haemolysins, adhesins and various hydrolytic enzymes. The present study was aimed to screen the pathogenic Aeromonas sp. in the marketed fish samples. About 20 fish samples were processed, in which 15 samples (75%) were found to be contaminated with Aeromonas. Conventional biochemical identification may lead to miss identification of Aeromonas isolates, so molecular based identification-16S rRNA gene was used for the identification of Aeromonas isolates. Further haemolytic activity of the Aeromonas isolates were performed on 5% blood agar plates and about 20% of the isolates showed α-haemolysis, 60% showed β-haemolysis and 20% showed γ-haemolysis. As proteolysis was reported as a virulent trait, the isolates were subjected to proteolytic activity on skim milk agar plates. About 73% of the isolates showed proteolysis. About 40% of the isolates possessed both the β-haemolytic and proteolytic activity. The presence of β-haemolytic and proteolytic activity among the Aeromonas isolates revealed the existence of pathogenic Aeromonas isolates in marketed fish

The Glove-like Structure of the Conserved Membrane Protein TatC Provides Insight into Signal Sequence Recognition in Twin-Arginine Translocation

In bacteria, two signal-sequence-dependent secretion pathways translocate proteins across the cytoplasmic membrane. Although the mechanism of the ubiquitous general secretory pathway is becoming well understood, that of the twin-arginine translocation pathway, responsible for translocation of folded proteins across the bilayer, is more mysterious. TatC, the largest and most conserved of three integral membrane components, provides the initial binding site of the signal sequence prior to pore assembly. Here, we present two crystal structures of TatC from the thermophilic bacteria Aquifex aeolicus at 4.0 Å and 6.8 Å resolution. The membrane architecture of TatC includes a glove-shaped structure with a lipid-exposed pocket predicted by molecular dynamics to distort the membrane. Correlating the biochemical literature to these results suggests that the signal sequence binds in this pocket, leading to structural changes that facilitate higher order assemblies

Case report on tuberous sclerosis: a rare cause of seizure

We report a case of tuberous sclerosis in a 19 years old teenage patient with generalized tonic-clonic seizure. MRI brain showed linear CSF filled structure with surrounding gliosis extending from the frontal horn of right lateral ventricle to the pial surface of right frontal lobe-postoperative change. Multiple small T2/ FLAIR hyper-intensities without diffusion restriction in bilateral frontal temporal parietal and left occipital lobes, predominantly involving the cortex and sub-cortical white matter and small focus of calcification in left parietal peri-ventricular white matter. He was treated with valproic acid, sodium valproate and levetiracetam and showed prompt improvement. Epilepsy in tuberous sclerosis complex is a group of genetic disorders manifesting in childhood. Secondary causes of tuberous sclerosis should be suspected when there is abrupt onset in adulthood. The case highlights an uncommon case of epilepsy in tuberous sclerosis in young adult patient

Penicillin V acylases from gram-negative bacteria degrade N-acylhomoserine lactones and attenuate virulence in Pseudomonas aeruginosa

Virulence pathways in gram-negative pathogenic bacteria are regulated by quorum sensing mechanisms, through the production and sensing of N-acylhomoserine lactone (AHL) signal molecules. Enzymatic degradation of AHLs leading to attenuation of virulence (quorum quenching) could pave the way for the development of new antibacterials. Penicillin V acylases (PVAs) belong to the Ntn hydrolase superfamily, together with AHL acylases. PVAs are exploited widely in the pharmaceutical industry, but their role in the natural physiology of their native microbes is not clearly understood. This report details the characterization of AHL degradation activity by homotetrameric PVAs from two gram-negative plant pathogenic bacteria, Pectobacterium atrosepticum (PaPVA) and Agrobacterium tumefaciens (AtPVA). Both the PVAs exhibited substrate specificity for degrading long-chain AHLs. Exogenous addition of these enzymes into Pseudomonas aeruginosa greatly diminished the production of elastase and pyocyanin and biofilm formation and increased the survival rate in an insect model of acute infection. Subtle structural differences in the PVA active site that regulate specificity for acyl chain length have been characterized, which could reflect the evolution of AHL-degrading acylases in relation to the environment of the bacteria that produce them and also provide strategies for enzyme engineering. The potential for using these enzymes as therapeutic agents in clinical applications and a few ideas about their possible significance in microbial physiology have also been discussed

Maternal and Neonatal Risk Factors Associated with Perinatal Depression—A Prospective Cohort Study

Background: Perinatal depression (PND) is often under-treated and under-recognized. It has a negative impact on infant development and mother–child interactions. This study aims to estimate the prevalence of PND during pregnancy and in the postpartum period and the effect of sociodemographic factors, psychosocial stressors, and obstetric and neonatal factors on PND. Methods: 166 antenatal mothers attending tertiary center, who completed the 1st-trimester, were evaluated on baseline sociodemographic, psychosocial, obstetric, neonatal, and post neonatal factors by using a semi-structured questionnaire. Periodic prospective assessments were done using Hamilton depression rating scale (HAMD) at the end of the second and third trimesters and first and sixth weeks of the postpartum period. Results: Prevalence of PND was 21.7%, 32.2%, 35%, 30.4%, and 30.6%, at the end of the first trimester, during second, and third trimesters, and first and sixth week postpartum, respectively. Factors significantly associated with depressive symptoms included history of previous children with illness (P: 0.013, OR—5.16, CI—1.3-19.5) and preterm birth (P: 0.037, OR—3.73, CI—1.1- 13.2) at the time of recruitment; history of abuse (P: 0.044, OR—3.26, CI—1.1-10.8) and marital conflicts (P: 0.003, OR—3.2, CI—1.4-6.9) by the end of second trimester; history of miscarriages (P: 0.012, OR—2.58, CI—1.2-5.4) by the end of third trimester; lower SES (P: 0.001, OR—3.48, CI—1.64-7.37), unsatisfied living conditions (P: 0.004, OR—2.9, CI—1.4-6.04), alcohol use in husband (P: 0.049, OR—2.01, CI—1.1-4.11), history of depressive episodes (P: 0.049, OR—2.09, CI—1.1-4.46), history of high-risk pregnancy (P: 0.008, OR—2.7, CI—1.29-5.64), history of miscarriages (P: 0.049, OR—2.04, CI—1.1-4.2), stressful events in the postpartum period (P: 0.043, OR—2.58, CI—1.01-6.59), IUD (P: 0.002), preterm birth (P: 0.001), congenital malformations (P: 0.001), dissatisfaction with the sex of the child (P: 0.005, OR—3.75, CI—1.42-9.91), poor family support (P: 0.001), and low birth weight (P: 0.001, OR—16.78, CI—6.32-44.53) in the postpartum period. These analyses are purely exploratory. Conclusions: PND is highly prevalent from the early antenatal period onwards; this warrants periodic assessment of depression among high-risk mothers, using a validated tool, for early diagnosis and management

Analysis of tail-anchored protein translocation pathway in plants

Tail-anchored (TA) proteins are a special class of membrane proteins that carry out vital functions in all living cells. Targeting mechanisms of TA proteins are investigated as the best example for post-translational protein targeting in yeast. Of the several mechanisms, Guided Entry of Tail-anchored protein (GET) pathway plays a major role in TA protein targeting. Many in silico and in vivo analyses are geared to identify TA proteins and their targeting mechanisms in different systems including Arabidopsis thaliana. Yet, crop plants that grow in specific and/or different conditions are not investigated for the presence of TA proteins and GET pathway. This study majorly investigates GET pathway in two crop plants, Oryza sativa subsp. Indica and Solanum tuberosum, through detailed in silico analysis. 508 and 912 TA proteins are identified in Oryza sativa subsp. Indica and Solanum tuberosum respectively and their localization with respect to endoplasmic reticulum (ER), mitochondria, and chloroplast has been delineated. Similarly, the associated GET proteins are identified (Get1, Get3 and Get4) and their structural inferences are elucidated using homology modelling. Get3 models are based on yeast Get3. The cytoplasmic Get3 from O. sativa is identified to be very similar to yeast Get3 with conserved P-loop and TA binding groove. Three cytoplasmic Get3s are identified for S. tuberosum. Taken together, this is the first study to identify TA proteins and GET components in Oryza sativa subsp. Indica and Solanum tuberosum, forming the basis for any further experimental characterization of TA targeting and GET pathway mechanisms in crop plants

Engineering Proteins for Thermostability with iRDP Web Server

<div><p>Engineering protein molecules with desired structure and biological functions has been an elusive goal. Development of industrially viable proteins with improved properties such as stability, catalytic activity and altered specificity by modifying the structure of an existing protein has widely been targeted through rational protein engineering. Although a range of factors contributing to thermal stability have been identified and widely researched, the <i>in silico</i> implementation of these as strategies directed towards enhancement of protein stability has not yet been explored extensively. A wide range of structural analysis tools is currently available for <i>in silico</i> protein engineering. However these tools concentrate on only a limited number of factors or individual protein structures, resulting in cumbersome and time-consuming analysis. The iRDP web server presented here provides a unified platform comprising of iCAPS, iStability and iMutants modules. Each module addresses different facets of effective rational engineering of proteins aiming towards enhanced stability. While iCAPS aids in selection of target protein based on factors contributing to structural stability, iStability uniquely offers <i>in silico</i> implementation of known thermostabilization strategies in proteins for identification and stability prediction of potential stabilizing mutation sites. iMutants aims to assess mutants based on changes in local interaction network and degree of residue conservation at the mutation sites. Each module was validated using an extensively diverse dataset. The server is freely accessible at <a href="http://irdp.ncl.res.in/" target="_blank">http://irdp.ncl.res.in</a> and has no login requirements.</p></div