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Latest Paper:
Bioresour Technol. 2012 Apr 9;:
22541951
Department of Biochemistry, University College of Science, Calcutta University, 35 Ballygunge Circular Road, West Bengal, Kolkata 700 019, India.
The activity and half-life of pectate lyase (PL) from Bacillus megaterium were nine- and 60-fold, respectively, higher at 90°C in the presence of hydroxyapatite nanoparticles (NP-PLs) than in the presence of 1mM CaCl(2). Thermodynamic analysis of the nanoparticle-induced stability revealed an enhanced entropy-enthalpy compensation by the NP-PLs since a reciprocal linearity of the enthalpy-entropy change to 90°C was observed. Without nanoparticles, the linearity range was 70°C. Such compensation reflected the maintenance of the native structure of proteins. The remarkable enhancement of activity and stability of the NP-PL system at high temperatures may be utilized commercially e.g. in the food industry or the processing of natural fibers that may require a thermotolerant enzyme.
K Gupta,
S Bhattacharya,
D Nandi,
A Dhar,
A Maity,
A Mukhopadhyay,
D J Chattopadhyay,
N R Ray,
P Sen,
U C Ghosh
Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700 073, India.
Arsenic(III) sorption was investigated with nanostructured cerium incorporated manganese oxide (NCMO). The pH between 6.0 and 8.0 was optimized for the arsenic(III) sorption. Kinetics and equilibrium data (pH=7.0±0.2, T=303±1.6K, and I=0.01M) of arsenic(III) sorption by NCMO described, respectively, the pseudo-second order and the Freundlich isotherm equations well. The sorption process was somewhat complicated in nature and divided into two different segments, initially very fast sorption followed by slow intraparticle diffusion process. Sorption reaction of arsenic(III) on NCMO was endothermic (ΔH°=+13.46kJmol(-1)) and spontaneous (ΔG°=-24.75 to -30.15kJmol(-1) at T=283-323K), which took place with increasing entropy (ΔS°=+0.14kJmol(-1)K(-1)) at solid-liquid interface. Energy of arsenic(III) sorption estimated by analyzing the equilibrium data using the D-R isotherm model was 15.4kJmol(-1), indicating the ion-exchange type mechanism. Raman, FT-IR, pH effect, desorption, etc. studies indicated that arsenic(III) was oxidized to arsenic(V) during the sorption process.
Northumbria Healthcare NHS Foundation Trust, UK; Specialist Trainee, Wansbeck General Hospital, Woodhorn Lane, Ashington, Northumberland NE63 9JJ, UK. dipankarchattopadhyay@hotmail.com.
Lemierre's syndrome is usually reported in the young and in fit individuals. We report a case of an 81-year-old woman who presented with thrombophlebitis of the internal jugular vein with a pulmonary embolism.
PLoS One. 2012 ;7 (4):e34623
22485180
Arindam Mondal,
Arunava Roy,
Sandipto Sarkar,
Jishnu Mukherjee,
Tridib Ganguly,
Dhrubajyoti Chattopadhyay
Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata, West Bengal, India.
The nucleocapsid protein (N) and the phosphoprotein (P) of nonsegmented negative-strand (NNS) RNA viruses interact with each other to accomplish two crucial events necessary for the viral replication cycle. First, the P protein binds to the aggregation prone nascent N molecules maintaining them in a soluble monomeric (N(0)) form (N(0)-P complex). It is this form that is competent for specific encapsidation of the viral genome. Second, the P protein binds to oligomeric N in the nucleoprotein complex (N-RNA-P complex), and thereby facilitates the recruitment of the viral polymerase (L) onto its template. All previous attempts to study these complexes relied on co-expression of the two proteins in diverse systems. In this study, we have characterised these different modes of N-P interaction in detail and for the first time have been able to reconstitute these complexes individually in vitro in the chandipura virus (CHPV), a human pathogenic NNS RNA virus. Using a battery of truncated mutants of the N protein, we have been able to identify two mutually exclusive domains of N involved in differential interaction with the P protein. An unique N-terminal binding site, comprising of amino acids (aa) 1-180 form the N(0)-P interacting region, whereas, C-terminal residues spanning aa 320-390 is instrumental in N-RNA-P interactions. Significantly, the ex-vivo data also supports these observations. Based on these results, we suggest that the P protein acts as N-specific chaperone and thereby partially masking the N-N self-association region, which leads to the specific recognition of viral genome RNA by N(0).
Department of Community Medicine, IPGME&R and SSKM Hospital, Kolkata 700020.
Cardiovascular diseases, mostly a lifestyle related disease is going to be an epidemic in near future. Eighty per cent deaths due to cardiovascular diseases occur in low and middle-income group of people. A cross-sectional observational study was undertaken among 208 care-providers of different departments of the Institute of Postgraduate Medical Education and Research, Kolkata to assess the prevalence of general, physical activity related and dietary risk factors. The study subjects were classified into medical (doctors), auxiliary (nurses, technical staffs) and supportive (peons, sweepers) categories according to their job responsibilities. With the help of risk factor scoring system developed by the investigators the prevalence of different category of risk factors were compared among different categories of care-providers in association with some related biological characteristics. The general risk factors found significantly increased (p < 0.001) with increase in age. The physical activity related risk scores were more in females than males. But the difference was not statistically significant. The supportive staffs had significantly higher general risk factors than doctors and auxiliary staffs. Regarding physical activity related risk factors it was significantly lower in supportive staffs than the other two categories. The picture was different in case of dietary risk factors that were found to be significantly lowest among auxiliary staffs.
Mrinal Kanti Bain,
Biplab Bhowmick,
Dipanwita Maity,
Dibyendu Mondal,
Md Masud Rahaman Mollick,
Bijan Kumar Paul,
Manas Bhowmik,
Dipak Rana,
Dipankar Chattopadhyay
Department of Polymer Science & Technology, University of Calcutta, 92 A.P.C. Road, Kolkata 700 009, India.
The effect of molecular weight of poly(vinyl alcohol)(PVA) and sodium chloride on the gelation temperature of methylcellulose (MC) was studied with the objective to develop a MC based formulation for sustained delivery of ketorolac tromethamine a model ophthalmic drug. Pure MC showed sol-gel transition at 61.2 °C. In order to reduce the gelation temperature of MC and to increase the drug release time, PVA was used. Different techniques such as test tube tilting method, UV-vis spectroscopy, viscometry and rheometry were used to measure gelation temperature of all the binary combinations of MC and PVA. It was observed that the gelation temperature of MC was reduced with the addition of 4% PVA and also the extent of reduction of the gelation temperature of MC was dependent on the molecular weight of PVA. The strong interactions between MC and PVA molecules were established using Fourier transform infrared spectroscopy. To study the in vitro drug release properties of the MC-PVA binary combinations, 6% sodium chloride was used to reduce the gelation temperature further up to physiological temperature. It was observed that the drug release time increased from 5 to 8h with the increase of molecular weight of PVA from 9×10(3) to 1.3×10(5) and this was due to the higher viscosity, better gel strength and greater interactions between the drug and PVA molecules in case of PVA (1.3×10(5)) compared to PVA (9×10(3)). In order to have an idea about the nature of interactions between the functional moieties of the drug and the polymer unit of PVA, a theoretical study was carried out.
Clinical Associate Lecturer, Newcastle University Consultant Vascular Surgeon Queen Elizabeth Hospital, Gateshead, NE9 6SX UK. vbhatta@yahoo.com.
Deep venous thrombosis (DVT) with its associated complications of pulmonary embolism and post-thrombotic syndrome are an important cause of morbidity and mortality. This review article provides an overview of the pathophysiology, risk factors and the guidelines for thromboprophylaxis. It also reviews the available modalities in the diagnosis and treatment of DVT. The newer methods of treatment are also discussed.
Samit Chatterjee,
Ved Prakash Dwivedi,
Yogesh Singh,
Imran Siddiqui,
Pawan Sharma,
Luc Van Kaer,
Debprasad Chattopadhyay,
Gobardhan Das
Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.
Despite its relatively poor efficacy, Bacillus Calmette-Guérin (BCG) has been used as a tuberculosis (TB) vaccine since its development in 1921. BCG induces robust T helper 1 (Th1) immune responses but, for many individuals, this is not sufficient for host resistance against Mycobacterium tuberculosis (M. tb) infection. Here we provide evidence that early secreted antigenic target protein 6 (ESAT-6), expressed by the virulent M. tb strain H37Rv but not by BCG, promotes vaccine-enhancing Th17 cell responses. These activities of ESAT-6 were dependent on TLR-2/MyD88 signalling and involved IL-6 and TGF-β production by dendritic cells. Thus, animals that were previously infected with H37Rv or recombinant BCG containing the RD1 region (BCG::RD1) exhibited improved protection upon re-challenge with virulent H37Rv compared with mice previously infected with BCG or RD1-deficient H37Rv (H37RvΔRD1). However, TLR-2 knockout (TLR-2(-/-)) animals neither showed Th17 responses nor exhibited improved protection in response to immunization with H37Rv. Furthermore, H37Rv and BCG::RD1 infection had little effect on the expression of the anti-inflammatory microRNA-146a (miR146a) in dendritic cells (DCs), whereas BCG and H37RvΔRD1 profoundly induced its expression in DCs. Consistent with these findings, ESAT-6 had no effect on miR146a expression in uninfected DCs, but dramatically inhibited its upregulation in BCG-infected or LPS-treated DCs. Collectively, our findings indicate that, in addition to Th1 immunity induced by BCG, RD1/ESAT-6-induced Th17 immune responses are essential for optimal vaccine efficacy.
Department of Medicine, University of Alabama at Birmingham, CBSE-250, 1015 18th Street South, Birmingham, AL 35294, USA.
The crystal structure of the catalytic domain of the ADP ribosylation factor GTPase-activating protein (ARFGAP) from Plasmodium falciparum has been determined and refined to 2.4 Å resolution. Multiwavength anomalous diffraction (MAD) data were collected utilizing the Zn(2+) ion bound at the zinc-finger domain and were used to solve the structure. The overall structure of the domain is similar to those of mammalian ARFGAPs. However, several amino-acid residues in the area where GAP interacts with ARF1 differ in P. falciparum ARFGAP. Moreover, a number of residues that form the dimer interface in the crystal structure are unique in P. falciparum ARFGAP.
Molecular and Applied Mycology and Plant Pathology Laboratory, Department of Botany, University of Calcutta, Kolkata, 700019, India.
The development of an eco-friendly and reliable process for the synthesis of gold nanomaterials (AuNPs) using microorganisms is gaining importance in the field of nanotechnology. In the present study, AuNPs have been synthesized by bio-reduction of chloroauric acid (HAuCl(4)) using the fungal culture filtrate (FCF) of Alternaria alternata. The synthesis of the AuNPs was monitored by UV-visible spectroscopy. The particles thereby obtained were characterized by UV, dynamic light scattering (DLS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM). Energy-dispersive X-ray study revealed the presence of gold in the nanoparticles. Fourier transform infrared spectroscopy confirmed the presence of a protein shell outside the nanoparticles which in turn also support their stabilization. Treatment of the fungal culture filtrate with aqueous Au(+) ions produced AuNPs with an average particle size of 12 ± 5 nm. This proposed mechanistic principal might serve as a set of design rule for the synthesis of nanostructures with desired architecture and can be amenable for the large scale commercial production and technical applications.
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