Simple and Rapid Method for Detecting Biofilm Forming Bacteria

Biofilm forming bacteria play a vital role in causing infectious diseases and for enhancing the efficiency of the bioremediation process through immobilization. Different media and conditions have been reported for detecting biofilm forming bacteria, however, they are not quite rapid. Here, we propose the use of a simple medium which can be used for detecting biofilm former, and also provide a mechanism to regulate the expression of biofilm formation process.     

Structural and inhibition analysis of novel sulfur-rich 2-mercaptobenzothiazole and 1,2,3-triazole ligands against <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> DprE1 enzyme

Mycobacterium tuberculosis decaprenylphosphoryl-β-d-ribose oxidase (MtbDprE1) acts in concert with decaprenylphosphoryl-β-d-ribose 2-epimerase (MtbDprE2) and catalyzes the epimerization of DPR into DPA. DPA is the sole precursor for synthesis of arabinogalactan and lipoarabinomannan in the mycobacterial cell wall. MtbDprE1 is a unique antimalarial drug target and many covalent and non-covalent inhibitors against MtbDprE1 have been studied for their antituberculosis activities. In the current study, we have purified MtbDprE1 enzyme and synthesized six sulfur-rich 2-mercaptobenzothiazole and 1, 2, 3-triazole conjugated ligands and performed binding analysis with MtbDprE1. All ligands have shown competitive binding, as observed for other covalently and noncovalently bound MtbDprE1 inhibitors. Molecular docking analysis of six ligands with MtbDprE1 shows that they occupy the substrate binding pocket of MtbDprE1 and are stabilized by hydrogen bonds and van der Waals interactions. Our study shows that sulfur-rich 2-mercaptobenzothiazole ligands act as specific inhibitors against MtbDprE1 and could be used as antituberculosis agents.     

Complete chloroplast genome of the medicinal plant Evolvulus alsinoides: comparative analysis,identification of mutational hotspots and evolutionary dynamics with species of Solanales

Evolvulus alsinoides, belonging to the family Convolvulaceae, is an important medicinal plant widely used as a nootropic in the Indian traditional medicine system. In the genus Evolvulus, no research on the chloroplast genome has been published. Hence, the present study focuses on annotation, characterization, identification of mutational hotspots, and phylogenetic analysis in the complete chloroplast genome (cp) of E. alsinoides. Genome comparison and evolutionary dynamics were performed with the species of Solanales. The cp genome has 114 genes (80 protein-coding genes, 30 transfer RNA, and 4 ribosomal RNA genes) that were unique with total genome size of 157,015 bp. The cp genome possesses 69 RNA editing sites and 44 simple sequence repeats (SSRs). Predicted SSRs were randomly selected and validated experimentally. Six divergent hotspots such as trnQ-UUG, trnF-GAA, psaI, clpP, ndhF, and ycf1 were discovered from the cp genome. These microsatellites and divergent hot spot sequences of the Taxa ‘Evolvulus’ could be employed as molecular markers for species identification and genetic divergence investigations. The LSC area was found to be more conserved than the SSC and IR region in genome comparison. The IR contraction and expansion studies show that nine genes rpl2, rpl23, ycf1, ycf2, ycf1, ndhF, ndhA, matK, and psbK were present in the IR-LSC and IR-SSC boundaries of the cp genome. Fifty-four protein-coding genes in the cp genome were under negative selection pressure, indicating that they were well conserved and were undergoing purifying selection. The phylogenetic analysis reveals that E. alsinoides is closely related to the genus Cressa with some divergence from the genus Ipomoea. This is the first time the chloroplast genome of the genus Evolvulus has been published. The findings of the present study and chloroplast genome data could be a valuable resource for future studies in population genetics, genetic diversity, and evolutionary relationship of the family Convolvulaceae.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-01051-w.     

Aluminium(III), chromium(III) and iron(III) complexes with 5-iodouracil and 5-iodouracil-histidine and their antitumour activity

Complexes of the type [Al(HL)(OH)Cl(2)], [M(HL)(OH)(2)Cl] and [M'(HL)(L')(OH)Cl], where HL = 5-iodouracil; HL' = histidine; M = Cr(III), Fe(III) and M' = Al(III), Cr(III), Fe(III), were synthesized and characterized. The complexes are polymeric showing high decomposition points and are insoluble in water and common organic solvents. The mu(eff) values, electronic spectral bands and ESR spectra suggest a polymeric 6-coordinate spin-free octahedral stereochemistry for the Cr(III) and Fe(III) complexes. 5-Iodouracil acts as a monodentate ligand coordinating to the metal ion through the O atom of C((4)) = O while histidine through the O atom of -COO(- ) and the N atom of -NH(2) group. In vivo antitumour effect of 5-iodouracil and its complexes was examined on C(3)H /He mice against P815 murine mastocytoma. As evident from their T/C values, Cr(III) and Fe(III) complexes display significant and higher antitumour activity compared to the 5-iodouracil ligand. The in vitro results of the complexes on the same cells indicate that Cr(III) and Fe(III) complexes show higher inhibition on (3)H-thymidine and (3)H-uridine incorporation in DNA and RNA replication, respectively, at a dose of 5 microg/mL.     

Comparative analysis of some models of gene regulation in mixed-substrate microbial growth

Mixed-substrate microbial growth is of fundamental interest in microbiology and bioengineering. Several mathematical models have been developed to account for the genetic regulation of such systems, especially those resulting in diauxic growth. In this work, we compare the dynamics of three such models (Narang, 1998a. The dynamical analogy between microbial growth on mixtures of substrates and population growth of competing species. Biotechnol. Bioeng. 59, 116-121; Thattai and Shraiman, 2003. Metabolic switching in the sugar phosphotransferase system of Escherichia coli. Biophys. J. 85(2), 744-754; Brandt et al., 2004. Modelling microbial adaptation to changing availability of substrates. Water Res. 38, 1004-1013). We show that these models are dynamically similar--the initial motion of the inducible enzymes in all the models is described by the Lotka-Volterra equations for competing species. In particular, the prediction of diauxic growth corresponds to "extinction" of one of the enzymes during the first few hours of growth. The dynamic similarity occurs because in all the models, the inducible enzymes possess properties characteristic of competing species: they are required for their own synthesis, and they inhibit each other. Despite this dynamic similarity, the models vary with respect to the range of dynamics captured. The Brandt et al. model always predicts the diauxic growth pattern, whereas the remaining two models exhibit both diauxic and non-diauxic growth patterns. The models also differ with respect to the mechanisms that generate the mutual inhibition between the enzymes. In the Narang model, mutual inhibition occurs because the enzymes for each substrate enhance the dilution of the enzymes for the other substrate. The Brandt et al. model superimposes upon this dilution effect an additional mechanism of mutual inhibition. In the Thattai and Shraiman model, the mutual inhibition is entirely due to competition for the phosphoryl groups. For quantitative agreement with the data, all models must be modified to account for specific mechanisms of mutual inhibition, such as inducer exclusion.     

Ecobiotechnological Approach for Exploiting the Abilities of Bacillus to Produce Co-polymer of Polyhydroxyalkanoate

Ecobiotechnological approach is an attractive and economical strategy to enrich beneficial microbes on waste biomass for production of Polyhydroxyalkanoate (PHA). Here, six strains of Bacillus spp. were used to produce co-polymers of PHA from pea-shells. Of the 57 mixed bacterial cultures (BCs) screened, two of the BCs, designated as 5BC1 and 5BC2, each containing 5 strains could produce PHA co-polymer at the rate of 505–560 mg/l from feed consisting of pea-shell slurry (PSS, 2 % total solids) and 1 % glucose (w/v). Co-polymer production was enhanced from 65–560 mg/l on untreated PSS to 1,610–1,645 mg/l from PSS treated with defined hydrolytic bacteria and 1 % glucose. Supplementation of the PSS hydrolysate with sodium propionate enabled 5BC1 to produce co-polymer P(3HB-co-3HV) with a 3HV content up to 13 % and a concomitant 1.46-fold enhancement in PHA yield. Using the principles of ecobiotechnology, this is the first demonstration of PHA co-polymer production by defined co-cultures of Bacillus from biowaste as feed under non-axenic conditions.     

Hydrogen and Polyhydroxybutyrate Producing Abilities of <Emphasis Type="Italic">Bacillus</Emphasis> spp. From Glucose in Two Stage System

Metabolic activities of four Bacillus strains to transform glucose into hydrogen (H₂) and polyhydroxybutyrate (PHB) in two stages were investigated in this study. Under batch culture conditions, Bacillus thuringiensis EGU45 and Bacillus cereus EGU44 evolved 1.67–1.92 mol H₂/mol glucose, respectively during the initial 3 days of incubation at 37°C. In the next 2 days, the residual glucose solutions along with B. thuringiensis EGU45 shaken at 200 rpm was found to produce PHB yield of 11.3% of dry cell mass. This is the first report among the non-photosynthetic microbes, where the Bacillus spp.—B. thuringiensis and B. cereus strains have been shown to produce H₂ and PHB in same medium under different conditions.     

Immobilization of rat brain acetylcholinesterase on porous gold-nanoparticle-CaCO₃ hybrid material modified Au electrode for detection of organophosphorous insecticides

An acetylcholinesterase (AChE) purified from rat brain was immobilized onto gold nanoparticles (AuNPs) assembled on the surface of porous calcium carbonate (CaCO₃) microsphere. The resulting AChE-AuNPs-CaCO₃ bioconjugate was mounted on the surface of Au electrode with the help of silica sol-gel matrix to prepare the working electrode. This electrode was connected to Ag/AgCl (3 M/saturated KCl) as standard and Pt wire as an auxiliary electrode through a potentiostat to construct an organophosphorus (OP) biosensor. The biosensor was based on inhibition of AChE by OP compounds/insecticides. The biosensor showed optimum response at pH 7.0, 30 °C, when polarized at +0.2 V. Two OP compounds, malathion and chlorpyrifos could be detected in the range of 0.1-100 nM and 0.1-70 nM, respectively at 2.0-3.0% inhibition level of AChE. The sensor was reactivated by immersing it in 0.1 mM 2-pyridine aldoxime for 10 min. The detection limit of the sensor was 0.1 nM for both malathion and chlorpyrifos. The biosensor exhibited good reusability (50 times without considerable loss) and storage stability (50% within 60 days, when stored at 4 °C).     

Site-specific analysis of heteronuclear Overhauser effects in microcrystalline proteins

Relaxation parameters such as longitudinal relaxation are susceptible to artifacts such as spin diffusion, and can be affected by paramagnetic impurities as e.g. oxygen, which make a quantitative interpretation difficult. We present here the site-specific measurement of [¹H]¹³C and [¹H]¹⁵N heteronuclear rates in an immobilized protein. For methyls, a strong effect is expected due to the three-fold rotation of the methyl group. Quantification of the [¹H]¹³C heteronuclear NOE in combination with ¹³C-R ₁ can yield a more accurate analysis of side chain motional parameters. The observation of significant [¹H]¹⁵N heteronuclear NOEs for certain backbone amides, as well as for specific asparagine/glutamine sidechain amides is consistent with MD simulations. The measurement of site-specific heteronuclear NOEs is enabled by the use of highly deuterated microcrystalline protein samples in which spin diffusion is reduced in comparison to protonated samples.