Thermodynamic and kinetic characteristics of an a-amylase from Bacillus licheniformis SKB4

An amylolytic bacterial strain, Bacillus licheniformis SKB4 produced maximum amylase at pH 6.5 at 42 °C, and at late stationary phase (24 h) of growth. Starch and peptone were found the best supporting carbon and nitrogen source with C:N ratio of 1:2 for amylase production. The purified enzyme was non-responsive to most of the metal ions except K+ and Mg++ (1.0 mM). The enzyme was stable and active at pH 6.5. The enzyme showed optimum temperature at 90 °C with 10 min of half life (t½) at 100 °C. The Q10 of the enzyme was 1.0. The thermodynamic principles like activation energy, free energy for substrate binding and transition state of the enzyme were found 31.53, 5.53 and -17.4 KJ/Mol of starch, respectively. The kinetic constant like Vmax, Km, K catand catalytic efficiency (Kcat/Km)for starch were found to be 1.04 μmol mg-1 min-1, 6.2 mg ml-1,2 × 103 S-1 and 3.22 × 102 ml mg-1 S-1,respectively. All these findings suggested that this amylase has unique characteristics for starch hydrolysis in respect to thermostability and kinetic properties

A Thiazole Coumarin (TC) turn-on fluorescence probe for AT-base pair detection and multipurpose applications in different biological systems

Sequence-specific recognition of DNA by small turn-on fluorescence probes is a promising tool for bioimaging, bioanalytical and biomedical applications. Here, the authors report a novel cell-permeable and red fluorescent hemicyanine-based Thiazole Coumarin (TC) probe for DNA recognition, nuclear staining and cell cycle analysis. TC exhibited strong fluorescence enhancement in the presence of DNA containing AT-base pairs, but did not fluoresce with GC sequences, single-stranded DNA, RNA and proteins. The fluorescence staining of HeLa S3 and HEK 293 cells by TC followed by DNase and RNase digestion studies depicted the selective staining of DNA in the nucleus over the cytoplasmic region. Fluorescence-Activated Cell Sorting (FACS) analysis by flow cytometry demonstrated the potential application of TC in cell cycle analysis in HEK 293 cells. Metaphase chromosome and malaria parasite DNA imaging studies further confirmed the in vivo diagnostic and therapeutic applications of probe TC. Probe TC may find multiple applications in fluorescence spectroscopy, diagnostics, bioimaging and molecular and cell biology

Antimicrobial resistance pattern, clustering mechanisms and correlation matrix of drug-resistant Escherichia coli in black Bengal goats in West Bengal, India

A cross-sectional study covering four agro-climatic zones of West Bengal, India, was carried out to understand the risk-factors, antimicrobial resistance mechanism and clustering of the resistance characteristics of Escherichia coli isolated from healthy (170) and diarrhoeic (74) goats reared under intensive (52) and semi-intensive (192) farming practices. Of the 488 E. coli isolates, the majority, including the extended spectrum (n: 64, 13.11%) and AmpC β-lactamase (ACBL) (n: 86, 17.62%) producers, were resistant to tetracycline (25.2%), followed by enrofloxacin (24.5%), cefotaxime (21.5%) and amikacin (20.5%). Statistical modelling revealed that the isolates from diarrhoeic animals (p < 0.001) are likely to be more ACBL-positive than those from the healthy counterparts. Similarly, cefotaxime (p < 0.05) and enrofloxacin-resistance (p < 0.01) were significantly higher in diarrhoeic goats and in goats reared intensively. The isolates (n = 35) resistant to multiple drugs revealed the presence of β-lactamase [blaCTXM-1-(21), blaSHV-(7), blaTEM-(3), blaCMY-6-(1), blaCITM-(3)]; quinolone [qnrB-(10), qnrS-(7), aac(6’)-Ib-cr-(3)]; tetracycline [tetA-(19), tetB-(4)] and sulphonamide resistance determinants [sul1-(4)]; multiple plasmids, especially those belonging to the IncF and IncI1 replicon types; and active acrAB efflux pumps. Further, two isolates harbored the carbapenem resistance (blaNDM-5) gene and eight were strong biofilm producers. This first ever study conducted to unravel the status of AMR in goat farming reveals that not only the intensive farming practices but also certain clinical ailments such as diarrhoea can increase the shedding of the drug-resistant isolate. The emergence of multi-drug resistant (MDR) E. coli in goats, particularly those that are carbapenem resistant, is a cause for concern that indicates the spread of such pathogens even in the livestock sub-sector generally considered as naive

A Biophysical Approach To Identify Active Sites Of Isolated Pure Herbal Compounds And Cell Signaling In Cancers

Natural compounds have exerts promising outcomes in cancer therapy for decades. These compounds provided several leads molecule, which are subsequently used in the blueprint of drug development in cancer treatment. For the search of lead compounds, we have selected a few medicinal plants from the various parts of our country. Barringtonia Racemosa has been used as traditional medicine for the treatment of various diseases. Anti-tumor property of the seed extract in mice model prompted us to search for the active component present in fruit extract. Quercetin 3-O-rutinoside (QOR) was isolated from the fruits of this plant and quantified by HPLC method. The compound was identified by IR, Mass, NMR (1D, 2D) spectral data analysis. QOR showed dose and time dependent anti-proliferative activity in several leukemic cell lines with negligible effect on normal human PBMC. Additionally, another Indian medicinal plant, curcuma caesia was selected for the identification of the active compound present in the plant material. Bio-active guided fractionation helped us in identification of an active compound present as (1s, 4s, 5s, 10R)- Zedoarondiol in the root extract. It showed cytotoxicity against different cancer cell lines. Next, Mahanine isolated from Murraya Koengii has been established as a potent anticancer molecule against different cancer including NSCLC. Even at early dose, mahanine inhibited phosphorylation of mTOR and also the total protein effectively in lower dose and as consequent events, inhibition of p70S6K and AKT were observed in NSCLC. To identify the active functional groups of mahanine responsible for biological activity, structure-activity relation was determined. Accordingly, -OH at C-7 and -NH were chemically modified. The concentration dependent anti-proliferative activity of mahanine and its four derivatives in an array of nineteen different cell lines from seven different types of cancers revealed that both C- 7-OH and NH groups are active functional groups responsible for its biological activity. Using several biophysical techniques we established that complexation of mahanine with DNA is minor groove bound conformation with high binding efficacy. These findings will help to design potent anti-cancer agent, which may be helpful for the development of target specific efficient drug

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Not AvailableEnvironment-friendly management of fruit flies involving pheromones is useful in reducing the undesirable pest populations responsible for decreasing the yield and the crop quality. A nanogel has been prepared from a pheromone, methyl eugenol (ME) using a low-molecular mass gelator. This was very stable at open ambient conditions and slowed down the evaporation of pheromone significantly. This enabled its easy handling and transportation without refrigeration, and reduction in the frequency of pheromone recharging in the orchard. Notably the involvement of the nano-gelled pheromone brought about an effective management of Bactrocera dorsalis, a prevalent harmful pest for a number of fruits including guava. Thus a simple, practical and low cost green chemical approach is developed that has a significant potential for crop protection, long lasting residual activity, excellent efficacy and favorable safety profiles. This makes the present invention well-suited for pest management in a variety of crops.Not Availabl

Identification and quantification of the active component quercetin 3-O-rutinoside from Barringtonia racemosa, targets mitochondrial apoptotic pathway in acute lymphoblastic leukemia

Barringtonia racemosa has been used as a traditional medicine for the treatment of various diseases. The antitumor property of the seed extract of this plant in mice model promotes us to search for the active component present in the fruit extract. Quercetin 3-O-rutinoside (QOR) has been isolated from the fruits of this plant for the first time and quantified by HPLC method. The compound was identified by IR, mass, and NMR (1D, 2D) spectral data analysis. QOR showed dose- and time-dependent anti-proliferative activity in several leukemic cell lines with negligible effect on normal human peripheral blood mononuclear cell (PBMC). A representative T-lineage acute lymphoblastic leukemia cell line (MOLT-3) showed phosphatidyl serine externalization and DNA fragmentation, indicating QOR-induced programed cell death. We established that QOR-induced apoptosis occurred preferentially on accumulation of cells in the sub-G0 phase and genomic DNA fragmentation through the activation of mitochondria-dependent caspase cascade for the first time in T-lineage ALL cell line

Electromagnetic interference shielding and thermal properties of non-covalently functionalized reduced graphene oxide/epoxy composites

Graphene oxide (GO) was non-covalently functionalized using sulfanilic acid azocromotrop (SAC) followed by hydrazine reduction to achieve SAC functionalized reduced GO (SAC-rGO). Fourier transform infrared spectra analysis and electrical conductivity measurements confirmed the successful functionlization and reduction of GO. The electrical conductivity of ~515 S•m−1 for SAC-rGO was recorded. The non-covalently functionalized reduced GO was subsequently dispersed in epoxy matrix at the loading level of 0.3 to 0.5 wt% to investigate its electromagnetic interference (EMI) shielding properties. The morphological and structural characterization of the SAC-rGO/epoxy composites was carried out using X-ray diffraction and Transmission electron microscopy analysis, which revealed the good dispersion of SAC-rGO in the epoxy. The SAC-rGO/epoxy composites showed the EMI shielding of −22.6 dB at the loading of 0.5 wt% SAC-rGO. Dynamical mechanical properties of the composites were studied to establish the reinforcing competency of the SAC-rGO. The storage modulus of the composites was found to increase within the studied temperature. Thermal stability of pure epoxy and its composites were compared by selecting the temperatures at 10 and 50% weight loss, respectively

Effect of Dodecyal Amine Functionalized Graphene on the Mechanical and Thermal Properties of Epoxy-Based Composites

Simultaneous surface functionalization and reduction of graphene oxide (GO) was achieved by using dodecyl amine (DA) as surface modifying agent. The DA modified reduced GO (DA-G) was used for subsequent preparation of DA-G/epoxy composites by solution mixing. Fourier transform infrared spectroscopy analysis, X-ray diffraction (XRD) and electrical conductivity measurements were conducted to establish the concurrent functionalization and reduction of GO. The effect of DA-G on the epoxy composites at 0 to 0.75 wt% loadings was studied by investigating its static and dynamical mechanical properties. XRD study was performed to verify the dispersion of DA-G in the epoxy polymer. Field emission scanning electron microscopy was used to investigate the fracture surface morphology of the composites and Transmission electron microscopy was employed to further confirm the dispersion of DA-G in the matrix. It was found that the tensile strength of the composite was increased by 38.8% with the addition of 0.5 wt% of DA-G. The good adhesion/interaction between DA-G and epoxy resulted in the increase of storage modulus; however, glass transition temperature (Tg) value of the composites shifted to lower temperature in comparison to the neat epoxy. Thermogravimetric analysis showed small decrease in onset degradation temperature for the composites as compared to neat epoxy except for the composites containing 0.75 wt% of DA-G