Due to the accumulation of cholesterol in arterial wall, clot-forming cascade activated in the blood capillaries lead to conditions like myocardial ischemia and heart failure. These clots are ...dissolved by the enzyme streptokinase (SK), produced by Streptococcus sp., a normal flora in the human body. In the present study, codon-dependent evolution of twenty-three SK from Streptococcus sp. bacteria, isolated from distinct geographical origins were analyzed. Besides, domain variation, compositional analysis, effective number of codons (ENc) plot, codon adaptation index (CAI), and effect of polymorphism on SK interaction with its substrate plasminogen (Plg) were analyzed. Codon usage bias varied within a tiny range. Studies also reveal that AT ending codons are preferred over GC ending codons. Analyses of the other parameters reveal that the mutational pressure is one of the main factors to shape codon usage biasness. Interfacing and polar contact forming amino acid residues of SK with Plg is identical for all Streptococcus dysgalactiae but not for all Streptococcus pyogenes. Changes of those interfacing amino acid sites exhibit a substantial effect on polar interaction between SK and Plg. The present in silico studies are expected to shed further light to characterize and moreover, to understand the various contributing factors to influence SK adaptation that will be fulfilling to develop efficient thrombolytic therapeutics.
•Systemic surveillance of rotavirus in children (≤5 years) hospitalized with diarrhea.•Rotavirus positively correlates with dehydration, mean hospital stay and vomiting.•Dynamicity of rotavirus ...genotypes among rural and urban settings during 2014–16.•Phylogenetic analyses and variation in antigenic epitopes of prevailing strains.
Group-A human rotaviruses (GARV) are among the major cause of childhood diarrhea worldwide. In lieu of monitoring the circulatory GARV strains and underscoring the burden of GARV related hospitalization, a systematic surveillance was conducted in three hospitals of eastern India. In this hospital-based diarrheal disease surveillance (2014–2016), GARV was the most common cause of acute infantile gastroenteritis. The strains were genotyped and characterized to understand their prevalence and phylodynamics prior to the introduction of vaccine in eastern India.
A total of 3652 stool samples were screened from children (≤5 years) hospitalized with acute diarrhea during 2014–2016. Initial screening for VP6 antigen was done by ELISA. GARV positive samples were genotyped by multiplex semi-nested PCR and DNA sequencing and phylogenetic analyses were based on the capsid proteins VP4 and VP7.
Of 3652 samples, 1817 (49.8%) were GARV positive. G1, G2, G3 and G9 in conjunction with P4, P6and P8genotypes were seen to co-circulate in the population. A sharp deflection from G1 to G3 occurred since 2016; upsurge of G9 strains was seen in alternate years, whereas G2 strains had a low frequency. All the circulating genotypes depicted a low phylogenetic relatedness to the vaccine strains. Differences in antigenic epitopes of VP4 and VP7 proteins in local strains were seen when compared to the vaccine strains. A significant difference in the degree of dehydration, duration of mean hospital stay and frequency of vomiting/24 h between GARV positive and negative children was evident.
The study provides a relevant set of base-line data on high burden of rotaviral gastroenteritis and the varied genotypic diversity among children prior to the introduction of GARV vaccine in this endemic region. Continuous monitoring during post-vaccination era will be required to assess the impact of vaccination in this region.
Polycyclic aromatic hydrocarbons (PAHs) are a group of environmental pollutant that are given top priority to maintain water and soil quality to the most amenable standard. Biodegradation of PAHs by ...bacteria is the convenient option for decontamination on site or off site. The aim of the present study was to isolate and identify naturally occurring bacteria having mixed PAHs biodegradation ability. The newly isolated
Pseudomonas putida
strain KD6 was found to efficiently degrade 97.729% of 1500 mg L
−1
mixed PAHs within 12 days in carbon-deficient minimal medium (CSM). The half-life (
t
1/2
) and degradation rate constant (
k
) were estimated to be 3.2 and 0.2165 days, respectively. The first-order kinetic parameters in soil by strain KD6 had shown efficient biodegradation potency with the higher concentration of total PAHs (1500 mg kg
−1
soil),
t
1/2
= 10.44 days
−1
. However, the biodegradation by un-inoculated control soil was found slower (
t
1/2
= 140 days
−1
) than the soil inoculated with
P. putida
strain KD6. The enzyme kinetic constants are also in agreement with chemical data obtained from the HPLC analysis. In addition, the sequence analysis and molecular docking studies showed that the strain KD6 encodes a mutant version of naphthalene 1,2-dioxygenase which have better Benzpyrene binding energy (−9.90 kcal mol
−1
) than wild type (−8.18 kcal mol
−1
) enzyme (chain A, 1NDO), respectively, with 0.00 and 0.08 RMSD values. The mutated naphthalene 1,2-dioxygenase
nah
Ac has six altered amino acid residues near to the ligand binding site. The strain KD6 could be a good bioresource for in situ or ex situ biodegradation of polycyclic aromatic hydrocarbon.
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We have reported for the first time a solvated electron mediated reduction of silver ion (Ag+) in presence of extract of Murraya koenigii (Mk) leaf as a surfactant to produce silver ...nanoparticles (AgNPs). Synthesized NPs show efficient ascorbic acid sensing at the µM range along with selective detection of different metal ions due to the presence of different biomolecules on the surface which are present in the extract. Synthesized nontoxic AgNPs will also exhibit proficient photocatalytic behavior for the degradation of toxic dyes due to the effective coupling between surface plasmon of AgNPs and the excited state continuum of the dye fluorophores. AgNPs will also exhibit substantial antibacterial activities. Altogether, our biosynthesized nontoxic NPs could be effectively used as both chemical and biosensor, catalyst as well as antibacterial agent.
Abstract : Lung surfactant, besides alveolar stability, also provides defence against pathogens by surfactant proteins (SP) , SP-A and SP-D. The hydrophobic proteins SP-B and SP-C enhance surface ...activity. An unusual and paradoxical effect of bovine LS and synthetic model LS with SP-B/-C was bactericidal to Staphylococcus aureus and Escherichia coli. Bacterial proliferation were investigated with bovine lung surfactant extract (BLES) , dipalmitoylphosphatdylcholine, palmitooleylglycerol, in combination with SPB/-C using standard microbiological colony forming unit (CFU) counts and structural imaging. BLES and other surfactant-SP-B/-C mixtures inhibit bacterial growth in the concentration range of 0-7.5mg/ml, at>10mg/mL paradoxical growth of both the bacterial species suggest antibiotic resistance. The lipid only LS have no effect on bacterial proliferation. Smaller peptide mimics of SP-B or SP-B1-25, were less efficient than SP-Cff. Ultra structural studies of the bacterial CFU using electron and atomic force microscopy suggest some membrane damage of S. aereus at inhibitory concentration of BLES, and some structural alteration of E. coli at dividing zones, suggesting utilization and incorporation of surfactant lipid species by both bacteria. The results depicted from in vitro studies are also in agreement with protein-protein interactions obtained from PatchDock, FireDock and ClasPro algorithm. The MD-simulation decipher a small range fluctuation of gyration radius of the LS proteins and their peptide mimics. The studies have alarming implications in the use of high dosages (100mg/mL/kg body weight) of exogenous surfactant for treatment of respiratory distress syndrome, genetic knockout abnormalities associated with these proteins, and the novel roles played by SP-B/C as bactericidal agents.
Twenty-four selected non-O1/non-O139Vibrio choleraestrains were examined for the presence of virulence associated genes likectxA,tcpA,toxRand the repetitive sequence (RS element). Seventeen of these ...were isolated from diarrhoeal stool samples while the remaining seven were of local environmental origin. Nine and four respectively of these strains were positive forctxAandtcpAby Multiplex PCR analysis. The majority (16 out of 18 tested) of the strains (including the fourtcpA+ strains) containedtoxRsequences as determined by another PCR assay. The presence of RS element was demonstrable inctxA+strains only. Interestingly, three of these non-O1/non-O139 strains were shown to contain all the three virulence associated genes (ctxA,tcpAandtoxR) as well as the RS element. Two of these belonged to serogroups 037 (V2) and 064 (CG15) while the third one (V315-1) was untypable. These three strains also produced cholera toxin, expressed toxin coregulated pilus (TCP) and/or TcpA related antigens when grown under appropriate culture conditions. Southern hybridization analysis of their chromosomal DNA fragments using DNA probes representingctxA, zot, aceand RS element revealed that the strains V2 and CG15 contained, at least, two complete copies of the CTX genetic element, while the strain V315-1 had three or more copies of the same. Presence of the RS element in these strains led to tandem duplication of the CTX genetic element in the chromosome of V2 and V315-1, but not in CG15 where the copies were likely to be present at different loci. These results also indicate the presence of additional copies of incomplete ‘core region’ withzotandacegenes, but notctxA, in strains V2 and CG15. The significance of these results in terms of the pathogenic and epidemic potential ofV. choleraestrains is discussed.
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