Dynamics of the occurrence of influenza in relation to seasonal variation in Chennai, Tamil Nadu: A 7 -year cumulative study

Background

Influenza viruses have emerged as virulent pathogens causing considerable burden across the world. A thorough understanding of the pattern in occurrence of influenza globally is the need of hour. The present study deals with analysis of the dynamics of Influenza virus, especially the influence of seasonal change on viral circulation and causation of epidemics/pandemics in the context of subtropical region.

Methods

During the 7 year (2009-2015) study, 36670 specimens were subjected to influenza analysis. Nasopharyngeal swabs collected from suspected patients from Chennai, Tamil Nadu, were tested and typed by real-time polymerase chain reaction assay.

Results

During 2009 pandemic, among influenza A positives 95.16% were Apdm09, indicating that there was a predominant circulation of Apdm09. During postpandemic period, there were waves in the occurrence of Apdm09 which indicates fall in immunity with buildup in the susceptible population.

Conclusion

In Chennai, Tamil Nadu, influenza positivity started with the onset of monsoon and peaks during the postmonsoon months throughout the study period. The assessment of meteorological factors compounding influenza activity can help in raising alerts to the public health officials of impending disaster which suggests that Influenza vaccination can be initiated before monsoon months in South India.

Development of antiviral inhibitor against dengue 2 targeting Ns3 protein: In vitro and in silico significant studies

Dengue fever is a severe, widespread disease with more than 2 million diagnosed infections per year. The Dengue virus protease represents a cardinal target for prudent drug design. Among the four serotypes Dengue 2 is known for the occurrence of its frequent epidemics. The new compound inhibited the Dengue-2 in the low-micromolar range in cells. At the moment, protease inhibitors are not actively tried against dengue virus as therapeutic option. We have identified thiosemicarbazones derived phenyl-acetyl ketones as candidate for a novel class of protease inhibitors. Here, we report the selective and non-competitive inhibition of the Dengue virus serotype 2 in vitro and in silico. Molecular docking suggests binding at a specific active site. In addition to the docking assays, few techniques were developed to interpret these molecules's antiviral profile in vitro.

Characterization and biological activities of extracellular melanin produced by Schizophyllum commune (Fries)

Melanins are enigmatic pigments produced by a wide variety of microorganisms including bacteria and fungi. Here, we have isolated and characterized extracellular melanin from mushroom fungus, Schizophyllum commune. The extracellular dark pigment produced by the broth culture of S. commune, after 21 days of incubation was recovered by hot acid-alkali treatment. The melanin nature of the pigment was characterized by biochemical tests and further, confirmed by UV, IR, EPR, NMR and MALDI-TOF Mass Spectra. Extracellular melanin, at 100 μg/ml, showed significant antibacterial activity against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas fluorescens and antifungal activity against Trichophyton simii and T. rubrum. At a concentration of 50 μg/ml, melanin showed high free radical scavenging activity of DPPH (2,2-diphenyl-1-picrylhydrazyl) indicating its antioxidant potential. It showed concentration dependent inhibition of cell proliferation of Human Epidermoid Larynx Carcinoma Cell Line (HEP-2). This study has demonstrated characterization of melanin from basidiomycetes mushroom fungus, Schizophyllum commune and its applications.

Genetic characterization, nickel tolerance, biosorption, kinetics, and uptake mechanism of a bacterium isolated from electroplating industrial effluent

Electroplating industries in Madurai city produce approximately 49,000 L of wastewater and 1200 L of sludge every day revealing 687-5569 ppm of nickel (Ni) with other contaminants. Seventeen Ni-tolerant bacterial strains were isolated from nutrient-enriched effluents. Among them one hyper Ni accumulating strain was scored and identified as Bacillus cereus VP17 on the basis of morphology, biochemical tests, 16S rDNA gene sequencing, and phylogenetic analysis. Equilibrium data of Ni(II) ions using the bacterium as sorbent at isothermal conditions (37 °C) and pH 6 were best adjusted by Langmuir (R(2) = 0.6268) and Freundlich models (R(2) = 0.9505). Experimental validation reveals Ni sorption takes place on a heterogeneous surface of the biosorbent, and predicted metal sorption capacity is 434 ppm. The pseudo-second-order kinetic model fitted the biosorption kinetic data better than the pseudo-first-order kinetic model (R(2) = 0.9963 and 0.3625). Scanning electron microscopy, energy dispersive X-ray, and Fourier transform infrared spectroscopy studies of the bacterial strain with and without Ni(II) ion reveals the biosorption mechanism. The results conclude possibilities of using B. cereus VP17 for Ni bioremediation.

Effect of organic-ligands on the toxicity profiles of CdS nanoparticles and functional properties

CdS nanoparticles are one among the most promising agents for fluorescent imaging. Hence, it is essential to develop new strategies to overcome the cytotoxicity of these nanoparticles. Surface modification is one of the simplest and effective techniques. This paper assesses the effect of surface modification on toxicity of the CdS nanoparticles. Unmodified CdS and surface-modified CdS nanoparticles were synthesized in an aqueous medium using a wet chemical route at room temperature. The surface modification of the CdS nanoparticles with polyvinylpyrrolidone (PVP) and cysteine was confirmed using infrared absorption studies. The diameters of unmodified CdS, PVP-modified CdS, and cysteine-modified CdS nanoparticles were determined using HRTEM. They exhibited luminescence in the range from 500 to 800 nm. The cytotoxic effects of these CdS nanoparticles were investigated in cultures of Vero cells. The results indicated that Vero cell viability was higher for the surface-modified CdS nanoparticles than for the unmodified CdS nanoparticles. The reduction in the toxicity was related to the nature of the capping agents used for the surface modification, and the particle size.

Abstract 5326: COSMIC: Enhancing the world's knowledge of somatic mutations in human cancer

COSMIC, the Catalogue Of Somatic Mutations In Cancer (http://cancer.sanger.ac.uk) is the world's largest and most comprehensive online resource for exploring the impact of somatic mutations in human cancer. Now running for over 10 years, the 67th release (Oct 2013) describes 1592109 mutations in 947213 tumour samples across 25606 genes. This information is curated manually from the scientific literature, and automatically from genome resequencing consortium data portals. Full curation of the scientific literature provides in-depth understanding of the impact that each gene has in human cancer, and this has been achieved for 127 point-mutated cancer genes, and 185 fusion gene pairs. Curated genes are selected from the Cancer Gene Census (http://cancer.sanger.ac.uk/census), a listing of all genes with substantial evidence implicating them in cancer promotion, currently numbering 513 and updated frequently.

The mutations discovered in the re-sequencing of over 8000 tumour genomes are now present in COSMIC (viewable in isolation from the genic curations, http://cancer.sanger.ac.uk/wgs). In addition, the Sanger has now fully exome sequenced 1015 common cancer cell lines, identifying 1146874 coding mutations annotated for functional significance, and this is available exclusively in COSMIC at (http://cancer.sanger.ac.uk/cell_lines). While COSMIC has focused on point mutations and gene fusions, many other mutation mechanisms cause oncogenesis and these are now being integrated. The 67th COSMIC release includes copy number mutations integrated into the database and major web page views. To allow easy graphical examination of this data, copy number information was reduced to ‘gain’ and ‘loss’ annotations for inclusion in histograms and tables, with much more precise detail available with a further click. Copy number data is available in detail for every gene in COSMIC, and also for every tissue. Exploring cancer via COSMIC’s Cancer Browser (http://cancer.sanger.ac.uk/cosmic/browse/tissue), results not just in a plot of the most mutated genes, but now also a circular genome plot summarizing the copy number gains and losses across all the samples from that tumour type, all explorable in more detail via clicks on the pictures.

As the genomic data increases in COSMIC, it is becoming more important to qualitatively annotate the information, indicating which is more important or significant to oncogenesis. We are now building systems to better highlight known or putative functional mutations, improving the signal-to-noise ratio of cancer genome resequencing.

Citation Format: C Boutselakis, S A. Forbes, P Gunasekaran, M Jia, D Beare, N Bindal, C Y. Kok, K Leung, D Minjie, R Shepherd, S Bamford, S Ward, C Cole, J W. Teague, M Stratton, P Campbell, U McDermott. COSMIC: Enhancing the world's knowledge of somatic mutations in human cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5326. doi:10.1158/1538-7445.AM2014-5326

Crystal structure of [4-(2-meth-oxy-phen-yl)-3-methyl-1-phenyl-6-tri-fluoro-methyl-1H-pyrazolo-[3,4-b]pyridin-5-yl](thio-phen-2-yl)methanone

The title compound, C26H18F3N3O2S, a 2-meth-oxy-substituted derivative, is closely related to its 4-methyl- and 4-chloro-substituted analogues and yet displays no structural relationships with them. The thio-phene ring is disorder free and the -CF3 group exhibits disorder, respectively, in contrast and similar to that observed in the 4-methyl- and 4-chloro-substituted derivatives. The torsion angle which defines the twist of the thio-phene ring is -69.6 (2)° (gauche) in the title compound, whereas it is anti-clinal in the 4-methyl- and 4-chloro-substituted derivatives, with respective values of 99.9 (2) and 99.3 (2)°. The absence of disorder in the thio-phene ring facilitates one of its ring C atoms to participate in the lone inter-molecular C-H⋯O hydrogen bond present in the crystal, leading to a characteristic C(5) chain graph-set motif linking mol-ecules related through glides along [010]. An intra-moleculr C-H⋯N hydrogen bond also occurs.

Extracellular synthesis and characterization of nickel oxide nanoparticles from Microbacterium sp. MRS-1 towards bioremediation of nickel electroplating industrial effluent

In the present study, a nickel resistant bacterium MRS-1 was isolated from nickel electroplating industrial effluent, capable of converting soluble NiSO4 into insoluble NiO nanoparticles and identified as Microbacterium sp. The formation of NiO nanoparticles in the form of pale green powder was observed on the bottom of the flask upon prolonged incubation of liquid nutrient medium containing high concentration of 2000ppm NiSO4. The properties of the produced NiO nanoparticles were characterized. NiO nanoparticles exhibited a maximum absorbance at 400nm. The NiO nanoparticles were 100-500nm in size with unique flower like structure. The elemental composition of the NiO nanoparticles was 44:39. The cells of MRS-1 were utilized for the treatment of nickel electroplating industrial effluent and showed nickel removal efficiency of 95%. Application of Microbacterium sp. MRS-1 would be a potential bacterium for bioremediation of nickel electroplating industrial waste water and simultaneous synthesis of NiO nanoparticles.

Identification of bacteria associated with underground parts of Crocus sativus by 16S rRNA gene targeted metagenomic approach

Saffron (Crocus sativus L), an autumn-flowering perennial sterile plant, reproduces vegetatively by underground corms. Saffron has biannual corm-root cycle that makes it an interesting candidate to study microbial dynamics in its rhizosphere and cormosphere (area under influence of corm). Culture independent 16S rRNA gene metagenomic study of rhizosphere and cormosphere of Saffron during flowering stage revealed presence of 22 genera but none of the genus was common in all the three samples. Bulk soil bacterial community was represented by 13 genera with Acidobacteria being dominant. In rhizosphere, out of eight different genera identified, Pseudomonas was the most dominant genus. Cormosphere bacteria comprised of six different genera, dominated by the genus Pantoea. This study revealed that the bacterial composition of all the three samples is significantly different (P < 0.05) from each other. This is the first report on the identification of bacteria associated with rhizosphere, cormosphere and bulk soil of Saffron, using cultivation independent 16S rRNA gene targeted metagenomic approach.

Modulatory effects of morin on hyperglycemia by attenuating the hepatic key enzymes of carbohydrate metabolism and β-cell function in streptozotocin-induced diabetic rats

The present study was aimed to evaluate the effect of morin on blood glucose, insulin level, hepatic glucose regulating enzyme activities and glycogen level in experimental diabetes. Diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin (STZ) (50 mg/kg b.w.). Five days after STZ injection, diabetic rats received morin (25 and 50 mg/kg b.w.) orally for 30 days. Glibenclamide was used as reference drug. Morin treatment significantly reduced the blood glucose and improved the serum insulin levels. Further, a dose-dependent reduction in glucose-6-phosphatase and fructose-1,6-bisphosphatase was observed along with the increase in liver hexokinase and glucose-6-phosphate dehydrogenase activities. Morin supplement were found to be effective in preserving the normal histological appearance of pancreatic islets as well as to preserve insulin-positive β-cells in STZ-rats. Therefore, these findings suggest that morin displays beneficial effects in the treatment of diabetes, mediated through the regulation of carbohydrate metabolic enzyme activities.

Protective effect of gallic acid on alloxan-induced oxidative stress and osmotic fragility in rats

In the present study, we investigated the antioxidant effect of gallic acid (GA) on membrane lipid peroxidation and osmotic fragility in alloxan-induced diabetic Wistar rats. GA was administered orally at doses of 5, 10, and 20 mg/kg body weight for 45 days, after which liver and kidney tissues were analyzed for the degree of lipid peroxidation, reduced glutathione, and the activities of antioxidants such as catalase, superoxide dismutase, and glutathione peroxidase. Administration of GA to alloxan-induced diabetic rats reduced the blood glucose level with an increase in the level of insulin. Liver and kidney tissues from diabetic animals exhibited disturbances in antioxidant defense compared with normal rats. GA at a dose of 20 mg/kg b.w. showed a significant effect than that of the other doses. In addition, the results revealed that GA protected the integrity of erythrocyte membrane in diabetic rats as demonstrated by lower percentage of hemolysis and resistance to hydrogen peroxide-induced peroxidation. The anti-hyperglycemic activity of GA in alloxan-induced diabetic rats was also comparable with glibenclamide, a reference drug. These results suggest that GA could provide a beneficial effect on diabetes by decreasing oxidative stress-related diabetic complications.

Genomics Perspectives of Bioethanol Producing Zymomonas Mobilis

In recent years, there has been continuous increase in demand for fossil fuels that has led to the need for new potential fuel sources. Biofuels, in particular ethanol, are of high interest because of dwindling fossil fuels. Among the ethanol producers, Zymomonas mobilis has acquired greater interest because it is a renewable source of bioethanol. Zymomonas mobilis is an aerotolerant, gram-negative, ethanol producing bacterium that shows high ethanol yield, tolerance, and greater productivity. This chapter focuses on recent efforts made to engineer Z. mobilis, transcriptomic, genome-based metabolomic studies, and bioinformatics exploitation of the available genomic data for the production of bioethanol. Recently, several bioinformatics tools have been used to predict the functional properties of the carbohydrate active ethanologenic enzymes in Z. mobilis. A number of processes were used to study the functional properties of the ethanologenic enzymes of Z. mobilis. Thus, functional genomics seeks to apply technologies that would help to improve the production of bioethanol by Z. mobilis.

A unique human rotavirus (non vaccine) G9P4 genotype infection in a child with gastroenteritis

Group A Rotaviruses with serotypes G1-G4 and G9 are the common Rotavirus types of clinical importance. This study aimed at determining the different Rotavirus genotypes in stool sample of children below 5 years. A total of 300 children with acute gastroenteritis were tested for group specific VP6 antigen of group A Rotaviruses by Enzyme Linked Immunosorbent Assay. 47 of these samples were positive for Rotavirus antigen. Out of these, 20 positive samples were subjected to Reverse Transcriptase Polymerase Chain Reaction for genotyping. The identified genotypes were G9P8, G1P8, G2P4, G9P4 (non-vaccine genotype), G1P6, and G1 (P types not identified in 5 samples).

5-Benzoyl-2-(1H-indol-3-yl)-4-[4-(propan-2-yl)phenyl]-4,5-dihydrofuran-3-carbonitrile

In the title compound, C₂₉H₂₄N₂O₂, the hydrofuran ring is twisted with puckering parameters Q = 0.1553 (16) Å and ϕ = 305.0 (6)°. In the crystal, the graph-set motifs of the inter­action pattern are an R₂²(16) motif involving dimers through N—H⋯N hydrogen bonds across centres of inversion and a C(6) motif through C—H⋯O hydrogen-bond between glide-related mol­ecules. Together, these generate [101] ladder-like chains.

Virulence Factors and Molecular cloning of Outer Membrane Protein (OMP) gene from virulent Aeromonas hyrophila isolated from infected gold fish Carassius auratus

Aeromonas hyrophila strains AHV1, AHV2 and AH3 were isolated and identified from Muscle tissue, intestine, body fluid and gills of infected gold fish Carassius auratus. In order to study their virulence, LD50 tests against  normal gold fish, proteolytic, haemolytic and challenge studies were performed. The virulence studies revealed that, both AHV1 and AHV2 strains are highly positive for proteolytic and haemolytic properties. The LD50 data showed that, the fish C. auratus are highly susceptible to A. hyrophila strains AHV1 and AHV2 at cent percent lethal rate. The survival of C. auratus significantly (P<0.05) decreased when challenged with virulent strains of A. hydrophila AHV1 and AHV2. The outer membrane protein (OMP-TS) gene was successfully amplified generating an the amplicon size of 1008 bp. The amplified product from the genomic DNA of AHV1 strain was cloned in to pTZ57R/T vector, transformed into DH5? cells and sequenced. The sequenced clone is resembling to various A. hydrophila isolates and submitted to NCBI GenBank database (accession no:HQ331525). DOI: http://dx.doi.org/10.3329/bjm.v28i2.11819 Bangladesh J Microbiol, Volume 28, Number 2, December 2011, pp 70-75

(±)-trans-5-Benzoyl-4-(3-bromophenyl)-2-(1H-indol-3-yl)-4,5-dihydrofuran-3-carbonitrile

The furan ring in the title compound, C₂₆H₁₇BrN₂O₂, adopts a twisted envelope conformation. The mol­ecular structure is stabilized by an intra­molecular C—H⋯O inter­action which generates an S(6) ring motif. The crystal packing is stabilized by N—H⋯O and C—H⋯Br inter­actions, generating an R₂²(16) ring motif and a C(12) linear chain motif, respectively. Weak C—H⋯π bonding is also observed.

(±)-trans-5-Benzoyl-2-(1H-indol-3-yl)-4-phenyl-4,5-dihydro-furan-3-carbonitrile

The furan ring in the title compound, C(26)H(18)N(2)O(2), is twisted about the C(H)-C(H) bond. The mol-ecular structure is stabilized by an intra-molecular C-H⋯O inter-action, which generates an S(6) ring motif. The presence of N-H⋯N hydrogen bonds leads to inversion dimers, which are stabilized in the crystal packing by C-H⋯O and C-H⋯π inter-actions, forming layers that stack along the a axis.

5-Benzoyl-2-(1H-indol-3-yl)-4-(4-methylphenyl)-4,5-dihydrofuran-3-carbonitrile

The furan ring in the title compound, C₂₇H₂₀N₂O₂, adopts a twisted conformation about the sp³—sp³ bond. The mol­ecular structure is stabilized by an intra­molecular C—H⋯O inter­action which generates an S(6) ring motif. The crystal packing is stabilized by N—H⋯O and C—H⋯O inter­actions generating centrosymmetric R₂²(18) and C(6) chain motifs, respectively. A weak C—H⋯π inter­action is also observed.

Development of a new method for diagnosis of Group B Coxsackie genome by reverse transcription loop-mediated isothermal amplification

BACKGROUND

Coxsackie B viruses (genus, Enterovirus; family, Picornaviridae) can cause aseptic meningitis, encephalitis, pleurodynia, and fatal myocarditis, and are implicated in the pathogenesis of dilated cardiomyopathy. The differentiation of the group B Coxsackieviruses into their subtypes has potential clinical and epidemiological implications.

OBJECTIVE

In this study, we developed a one-step, single-tube genogroup-specific reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the detection of group B Coxsackie genomes targeting 5' UTR region.

MATERIALS AND METHODS

The amplification can be obtained in less than 1 hour by incubating all the reagents in a single tube with reverse transcriptase and Bst DNA polymerase at 63°C. Detection of gene amplification could be accomplished by agarose gel electrophoresis and the monitoring of gene amplification can also be visualised with the naked eye by using SYBR green I fluorescent dye.

RESULTS

A total of 40 samples comprising 31 positive samples and 9 negative samples were used in this study for comparative evaluation. The results were compared with those from Real-Time Polymerase Chain Reaction (RT-PCR). None of the RT-PCR-positive samples were missed by RT-LAMP, thereby indicating a higher sensitivity of the RT-LAMP assay.

CONCLUSION

Thus, due to easy operation without a requirement of sophisticated equipment and skilled personnel, the RT-LAMP assay reported here is extremely rapid, cost-effective, highly sensitive, and specific and has potential usefulness for rapid detection of non-polio enterovirus (NPEV) not only by well-equipped laboratories but also by peripheral diagnostic laboratories with limited financial resources in developing countries.

Molecular epidemiology of measles in India, 2005-2010

Measles is a childhood disease that causes great morbidity and mortality in India and worldwide. Because measles surveillance in India is in its infancy, there is a paucity of countrywide data on circulating Measles virus genotypes. This study was conducted in 21 of 28 States and 2 of 7 Union Territories of India by MeaslesNetIndia, a national network of 27 centers and sentinel practitioners. MeaslesNetIndia investigated 52 measles outbreaks in geographically representative areas from 2005 through June 2010. All outbreaks were serologically confirmed by detection of antimeasles virus immunoglobulin M (IgM) antibodies in serum or oral fluid samples. Molecular studies, using World Health Organization (WHO)-recommended protocols obtained 203 N-gene, 40 H-gene, and 4 M-gene sequences during this period. Measles genotypes D4, D7, and D8 were found to be circulating in various parts of India during the study period. Further phylogenetic analysis revealed 4 lineages of Indian D8 genotypes: D8a, D8b, D8c, and D8d. This study generated a large, countrywide sequence database that can form the baseline for future molecular studies on measles virus transmission pathways in India. This study has created support and capabilities for countrywide measles molecular surveillance that must be carried forward.

Dengue disease status in Chennai (2006-2008): a retrospective analysis

BACKGROUND & OBJECTIVES

Dengue is one of the most important Arboviral diseases in man with outbreaks in Southeast Asia and India. We report a retrospective analysis of the dengue positivity in the referred samples for three years period (2006 to 2008) at the Department of Virology, King Institute of Preventive Medicine, Chennai, Tamil Nadu, India.

METHODS

Serum samples from 1593 suspected cases (968 male and 625 female) were obtained. Of the 1593 cases screened, 1204 (75.5%) were paediatric cases and 389 (24.4%) adults. The samples were subjected to MAC ELISA and IgG ELISA.

RESULTS

Of the 968 patients, 686 (43.0%) were positive, of which 579 (84.0%) were in the paediatric age group (<14 yr) and 107 (15.5%) were adults. The IgM positivity being 356 (36.7%) in males and 330 (52.8%) in females. Of the 686 positives, 113 (16.47%) were positive for both IgM and IgG denoting secondary infection. There was a noticeable increased occurrence during the cooler months and during the monsoon and post-monsoon months.

INTERPRETATION & CONCLUSION

The dengue IgM seropositivity among the suspected cases indicates active dengue virus activity. Increase in the probable secondary infections especially in a country like ours where multiple serotypes are prevalent raises concern over probable increase in the incidence of the more serious DHF/DSS. Studies need to be done to identify circulating serotypes of dengue virus to design preventive strategies.

Human microbiomics

The sequencing of the human genome has driven the study of human biology in a significant way and enabled the genome-wide study to elucidate the molecular basis of complex human diseases. Recently, the role of microbiota on human physiology and health has received much attention. The influence of gut microbiome (the collective genomes of the gut microbiota) in obesity has been demonstrated, which may pave the way for new prophylactic and therapeutic strategies such as bacteriotherapy. The significance and recent understandings in the area of "human microbiomics" are discussed here.

Microbial phylogeny and diversity: small subunit ribosomal RNA sequence analysis and beyond

Small subunit ribosomal RNA (16S rRNA) gene sequence analysis is used for the identification and classification of prokaryotes. In addition, sequencing of 16S rRNA genes amplified directly from the environment is used to estimate microbial diversity. The presence of mosaicism, intra-genomic heterogeneity and the lack of a universal threshold sequence identity value limit 16S rRNA-based phylogenetic analysis. PCR-amplification bias and cloning bias can also result in an inaccurate representation of the microbial diversity. In this review, recently reported complexities of 16S rRNA gene sequence analyses and the requirement of additional tools for microbial phylogeny and diversity analyses are discussed.

Role of Val289 residue in the alpha-amylase of Bacillus amyloliquefaciens MTCC 610: an analysis by site directed mutagenesis

The Val289 residue in the alpha-amylase of Bacillus amyloliquefaciens, which is equivalent to the Ala289 and Val286 residues in the alpha-amylases of B. stearothermophilus and B. licheniformis, respectively, was studied by site-directed mutagenesis. This residue was substituted with 10 different amino acids by random substitution of the Val codon. In these mutant alpha-amylases, Val289 was substituted with Ile, Tyr, Phe, Leu, Gly, Pro, Ser, Arg, Glu, and Asp. Compared with the wild-type alpha-amylase, the mutant alpha-amylase Val289Ile showed 20% more hydrolytic activity, whereas Val289Phe and Val289Leu showed 50% lesser activity. On the other hand, the mutant alpha-amylases Val289Gly, Val289Tyr, Val289Ser, and Val289Pro showed less than 15% activity. The substitution of Val289 with Arg, Asp, or Glu resulted in complete loss of the alpha-amylase activity. Interestingly, the mutant alpha-amylase Val289Tyr had acquired a transglycosylation activity, which resulted in the change of product profile of the reaction, giving a longer oligosaccharide.

Induction of alcohol-metabolizing enzymes and heat shock protein expression by ethanol and modulation by fenugreek seed polyphenols in Chang liver cells

The present study investigated the effect of fenugreek seed polyphenolic extract (FPEt) on ethanol-induced protein expression in Chang liver cells. Cells were incubated with either 30 mM EtOH alone or together in the presence of FPEt for 24 h. Cells were harvested and assessed for expression of alcohol metabolizing enzymes-alcohol dehydrogenase (ADH(2) isoform), aldehyde dehydrogenase (ALDH(2) isoform), cytochrome P450 (CYP2E1), the electron transport component (cytochrome-c), and the heat shock proteins. The expression of ADH(2), ALDH(2), and CYP2E1 were upregulated, whereas the expression of cytochrome-c was downregulated in the ethanol-treated cells. The expression of cellular heat shock proteins-HSP70, HSC70, HSC92, and mitochondrial protein mtHSP70 were induced in ethanol-treated Chang liver cells. FPEt modulated the protein expression changes induced by ethanol and had no effect when incubated with normal Chang liver cells. FPEt might exert cytoprotective action on ethanol-induced liver cell damage, possibly by enhancing cellular redox status.

Production and characterization of a low-molecular-weight bacteriocin from Bacillus licheniformis MKU3

AIMS

Enhancing production and characterization of a low-molecular-weight bacteriocin from Bacillus licheniformis MKU3.

METHODS AND RESULTS

The culture supernatant of B. licheniformis MKU3 exhibited bacteriocin-like activity against gram-positive and -negative bacteria and different fungi and yeast. SDS-PAGE analysis of the extracellular proteins of B. licheniformis MKU3 revealed a bacteriocin-like protein with a molecular mass of 1.5 kDa. This bacteriocin activity was found to be stable under a pH range of 3.0-10.0 and at temperatures up to 100 degrees C for 60 min, but inactivated by proteinase K, trypsin or pronase E. An experimental fractional factorial design for optimization of production medium resulted in a maximum activity of bacteriocin (11,000 AU ml(-1)) by B. licheniformis MKU3.

CONCLUSIONS

A low-molecular-weight bacteriocin-like protein from B. licheniformis MKU3 exhibited a wide spectrum of antimicrobial activity against several gram-positive bacteria, several fungi and yeast. A 3.6-fold increase in the production of bacteriocin was achieved using the culture medium optimized through a fractional factorial design.

SIGNIFICANCE AND IMPACT OF THE STUDY

A bacteriocin with wide spectrum of activity against gram-positive bacterial pathogens, filamentous fungi and yeast suggested its potential clinical use. Statistical method facilitated optimization of cultural medium for the improved production of bacteriocin.

Sustained expression of keratinase gene under PxylA and PamyL promoters in the recombinant Bacillus megaterium MS941

The ker gene encoding pre-pro keratinase of Bacillus licheniformis MKU3 was cloned with xylose inducible promoter (PxylA) or alpha-amylase promoter (PamyL) or both in Escherichia coli-Bacillus shuttle vector, pWH1520 generating recombinant plasmids pWHK3, pWAK3 and pWXAK3 respectively. Compared with Bacillius megaterium MS941 (pWXAK3) expressing ker gene with PxylA-PamyL promoters, B. megaterium MS941 (pWAK3) with PamyL displayed higher keratinase yield (168.6 U/ml) and specific activity (14.59 U/mg) after 36 h of growth in LB medium, however the keratinase yield decreased in the culture grown in LB medium supplemented with starch or xylose or both. A maximum yield of 186.3 U/ml with specific activity of 17.25 U/mg was obtained from xylose induced keratinase expression in B. megaterium MS941 (pWHK3) grown for 24h. The recombinant plasmids were stably maintained with sustained expression of keratinase for about 60 generations in B. megaterium MS941 rather than in B. megaterium 1,4945.

Strategies for accessing soil metagenome for desired applications

Most of the microorganisms in nature are inaccessible as they are uncultivable in the laboratory. Metagenomic approaches promise the accessibility of the genetic resources and their potential applications. Genetic resources from terrestrial environments can be accessed by exploring the soil metagenome. Soil metagenomic analyses are usually initiated by the isolation of environmental DNAs. Several methods have been described for the direct isolation of environmental DNAs from soil and sediments. Application of metagenomics largely depends on the construction of genomic DNA libraries and subsequent high-throughput sequencing or library screening. Thus, obtaining large quantities of pure cloneable DNA from the environment is a prerequisite. This review discusses the recent developments related to efficient extraction and purification of soil metagenome highlighting the considerations for various metagenomic applications.

Cloning and expression of keratinase gene in Bacillus megaterium and optimization of fermentation conditions for the production of keratinase by recombinant strain

AIMS

Cloning and expression of keratinase gene in Bacillus megaterium and optimization of fermentation conditions for the production of keratinase by recombinant strain.

METHODS AND RESULTS

The keratinase gene with and without leader sequence from the chromosomal DNA of Bacillus licheniformis MKU3 was amplified by PCR and cloned into pET30b and transferred into Escherichia coli BL21. The ker gene without leader sequence only expressed in E. coli and the recombinant strain produced an intracellular keratinase activity of 74.3 U ml(-1). The ker gene was further subcloned into E. coli-Bacillus shuttle vector, pWH1520. Bacillus megaterium ATCC 14945 carrying the recombinant plasmid pWHK3 expressed the ker gene placed under xylA promoter and produced an extracellular keratinase activity of 95 U ml(-1). Response surface methodology (RSM) was employed to optimize the fermentation condition and to improve the level of keratinase production by the recombinant strain. A maximum keratinolytic activity of 166.2 U ml(-1) (specific activity, 33.25 U mg(-1)) was obtained in 18 h of the fermentation carried out with an initial inoculum of 0.4 OD600 nm and xylose concentration of 0.75% w/v.

CONCLUSIONS

Bacillus licheniformis keratinase was cloned and successfully expressed using T7 promoter in E. coli and xylose inducible expression system in B. megaterium. Response surface methodology was employed to optimize the process parameters, which resulted in a three-fold higher level of keratinase production by the recombinant B. megaterium (pWHK3) than the wild type strain B. licheniformis MKU3.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study suggests that B. megaterium is a suitable host for the expression of cloned genes from heterologous origin. Optimization of fermentation conditions improved the keratinase production by B. megaterium (pWHK3) and suggested that this recombinant strain could be used for the production of keratinase.

In vitro evaluation of the anticancer effect of lactoferrin and tea polyphenol combination on oral carcinoma cells

We investigated the anticancer effects of green and black tea polyphenols alone and in combination with bovine milk lactoferrin (bLF) on human tongue squamous carcinoma (CAL-27) and normal human gingival fibroblast (HGF) cells. Both green (Polyphenon-E;P-E) and black tea polyphenols (Polyphenon-B;P-B) preferentially inhibit the growth of CAL-27 cells in a dose-dependent manner. Based on the IC(50) values, P-E was found to be more effective than P-B and the combination of P-E and bLF (1:2 ratio) exhibited synergistic inhibition of CAL-27 cells. Analysis of the mechanism revealed nuclear fragmentation and condensation with appearance of the A(o) peak indicative of apoptosis. Furthermore, tea polyphenols transduced the apoptosis signal via generation of reactive oxygen species and decrease in the Bcl-2/Bax ratio thereby inducing mitochondrial permeability transition with consequent activation of caspase-3. Overall, the potency of cytotoxic and apoptosis inducing effects of dietary agents on CAL-27 cells was in the order P-E and bLF combination (1:2 ratio)>P-E>P-B. These results suggest that a "designer" approach may be useful for oral cancer prevention strategies.

Application of cross-linked enzyme aggregates of Bacillus badius penicillin G acylase for the production of 6-aminopenicillanic acid

AIMS

Optimization of 6-aminopenicillanic acid (6-APA) production using cross-linked enzyme aggregates (CLEA) of Bacillus badius penicillin G acylase (PAC).

METHODS AND RESULTS

CLEA-PAC was prepared using purified/partially purified PAC with phenylacetic acid as active-site blocking agent and glutaraldehyde as cross-linker. Conversion of penicillin G to 6-APA by CLEA-PAC was optimized using response surface methodology (RSM) (central composite rotatable design) consisting of a three-factor-two-level pattern with 20 experimental runs.

CONCLUSION

Nearly, 80% of immobilization yield was obtained when partially purified enzyme was used for the preparation of CLEA-PAC. Quantitative conversion of penicillin G to 6-APA was observed within 60 min and the CLEA-PAC was reusable for 20 repeated cycles with 100% retention of enzyme activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The faster conversion of penicillin G to 6-APA by CLEA-PAC and efficient reusability holds a strong potential for the industrial application.

Toxicity assessment and microbial degradation of azo dyes

Toxic effluents containing azo dyes are discharged from various industries and they adversely affect water resources, soil fertility, aquatic organisms and ecosystem integrity. They pose toxicity (lethal effect, genotoxicity, mutagenicity and carcinogenicity) to aquatic organisms (fish, algae, bacteria, etc.) as well as animals. They are not readily degradable under natural conditions and are typically not removed from waste water by conventional waste water treatment systems. Benzidine based dyes have long been recognized as a human urinary bladder carcinogen and tumorigenic in a variety of laboratory animals. Several microorganisms have been found to decolourize, transform and even to completely mineralize azo dyes. A mixed culture of two Pseudomonas strains efficiently degraded mixture of 3-chlorobenzoate (3-CBA) and phenol/cresols. Azoreductases of different microorganisms are useful for the development of biodegradation systems as they catalyze reductive cleavage of azo groups (-N=N-) under mild conditions. In this review, toxic impacts of dyeing factory effluents on plants, fishes, and environment, and plausible bioremediation strategies for removal of azo dyes have been discussed.

Production of ethanol from liquefied cassava starch using co-immobilized cells of Zymomonas mobilis and Saccharomyces diastaticus

Co-immobilized cells of Saccharomyces diastaticus and Zymomonas mobilis produced a high ethanol concentration compared to immobilized cells of S. diastaticus during batch fermentation of liquefied cassava starch. The co-immobilized cells produced 46.7 g/l ethanol from 150 g/l liquefied cassava starch, while immobilized cells of yeast S. diastaticus produced 37.5 g/l ethanol. The concentration of ethanol produced by immobilized cells was higher than that by free cells of S. diastaticus and Z. mobilis in mixed-culture fermentation. In repeated-batch fermentation using co-immobilized cells, the ethanol concentration increased to 53.5 g/l. The co-immobilized gel beads were stable up to seven successive batches. Continuous fermentation using co-immobilized cells in a packed bed column reactor operated at a flow rate of 15 ml/h (residence time, 4 h) exhibited a maximum ethanol productivity of 8.9 g/l/h.

Improvement of xylanase production in solid state fermentation by alkali-tolerant Aspergillus fumigatus MKU1 using a fractional factorial design

Optimization of media for the maximum production of xylanase by Aspergillus fumigatus MKUI was carried out using De Meo's fractional factorial design with seven components such as NaNO3, K2HPO4, MgSO4, FeSO4. KCl, peptone and yeast extract. A. fumigatus produced a maximum of 700 U/gds of enzyme after 48 hr of incubation (before optimization). After two steps of optimization, the medium designed favoured a 2.8 fold (1950 U/gds) increase in xylanase production by A. fumigatus. Optimized medium for Aspergillus fumigatus contained (g/l) NaNO3, 15; K2HPO4, 15; MgSO4, 5; FeSO4, 0.009; KCI, 0.5; peptone, 20; and yeast extract, 10.

Optimization of medium composition for alkali-stable xylanase production by Aspergillus fischeri Fxn 1 in solid-state fermentation using central composite rotary design

Response surface methodology and central composite rotary design (CCRD) was employed to optimize a fermentation medium for the production of alkali-stable cellulase-free xylanase by Aspergillus fischeri in solid-state fermentation at pH 9.0 with wheat bran as substrate. The four variables involved in this study were sodium nitrite, potassium dihydrogen phosphate, magnesium sulphate and yeast extract. The statistical analysis of the results showed that, in the range studied, only sodium nitrite had a significant effect on xylanase production. The optimized medium containing (in g/l) NaNO(2)-7.0, K2HPO(4)-1.0, MgSO(4)-0.5 and yeast extract-5.0 resulted in 1.9-fold increased level of alkali-stable xylanase (1024 U/g wheat bran) production compared to initial level (540 U/g) after 72 h of fermentation, whereas its value predicted by the quadratic model was 931 U/g. The level of protease activity was considerably decreased in optimized medium, thus helping to preserve the xylanase activity and demonstrating another advantage of applying statistical experimental design.