IMTECH Research Articles

Biochemical characterization of a lead-tolerant strain of Aspergillus foetidus: An implication of bioremediation of lead from liquid media

The fungus Aspergillus foetidus isolated from wastewater treatment center, Kalyani was identified primarily as a lead (Pb+2) tolerant strain by supplementation experiments with high concentrations of Pb and confirmed the fungal strain as, A. foetidus MTCC 8876 after identification from the Microbial Type Culture Collection and Gene Bank (MTCC), Institute of Microbial Technology (IMTECH), Chandigarh, India. Growth studies in liquid Czapek-Dox (CD) media with different Pb treatments showed an initial growth increase up to 200 mg L−1 Pb treatment followed by gradual decrease at higher Pb doses. Protein and thiol leakage during growth experiments in CD broth containing Pb+2 may be due to disturbance in membrane structure as was further evident from lipid peroxidation induced by Pb. The strain was efficient in removing Pb from the liquid growth medium by mycelial biosorption. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopic (EDS) analysis confirmed the presence of tightly bound Pb as insoluble crystals outside fungal mycelia. Intracellular proline level and activities of the antioxidative enzymes increased up to a certain level to detoxify malondialdehyde and H2O2 produced by Pb toxicity. These data indicate that the test strain has some inherent mechanisms to tolerate unusually high Pb doses and high Pb uptake potential, pre-requisite for acting as a suitable candidate for Pb bioremediation from contaminated aqua-environment.

A novel approach to prevent candidiasis associated with long term administration of cephalosporins

BackgroundAntibiotics play a critical role in the pathogenesis of Candida infections by invading the competent indigenous flora. Very little is known about the antifungal activity of third generation cephalosporins, but several new groups of cephalosporins were reported to show in vitro antifungal activity. EDTA, a chelating and permeable agent has been found to exhibit the effective antifungal activity. The purpose of the study was to evaluate the in vitro antifungal activity of Elores, a novel antibiotic adjuvant entity having combination of ceftriaxone, sulbactam and EDTA against ceftriaxone alone in Candida albicans in an attempt to prevent the risk of candidiasis after a prolonged cephalosporin antibiotic treatment. MethodsC. albicans (MTCC-227) procured from Institute of Microbial Technology (IMTECH) Chandigarh was used in the study. Antifungal susceptibility of the drugs was determined by agar well diffusion method. Agar dilution and tube dilution methods were used to assess the anti-proliferative activity of Elores and EDTA. ResultsElores containing EDTA equivalent to 6.25 and 12.5 μg/ml effectively suppressed the growth and the difference was 1318 CFU/ml between ceftriaxone and test sample, which is more significant in preventing overgrowth of Candida. ConclusionThe study showed that Elores effectively slowdown the Candida over growth at serum level EDTA concentrations and believed to prevent candidiasis, associated with prolonged cephalosporin antibiotic treatment therapies.

R & D Performance of CSIR-IMTECH (India): A Scientometric Study based on the Papers published during 1991–1995 and 2005–2009

The study analyses the publications output of Council of Scientific and Industrial Research -Institute of Microbial Technology (IMTECH), India, published during 1991–1995 and 2005–2009 and assesses how science at CSIR-IMTECH India has progressed over the time. The publication output has been analysed using quantitative and qualitative indicators, such as the number of papers published in Science Citation Index SCI and non-SCI journals during the 1991–95 and 2005–09, normalised impact factor per paper, citations received per paper, subject-wise areas of research distribution, international collaboration with the other countries and characteristics of the highly productive authors of the institute.

Isolation and screening of alkaline protease producing bacteria and induction of overproducing Bacillus licheniformis mutants through UV irradiation

Screening was done from soil samples collected from black cotton soil, groundnut field, milk processing unit, Kotappakonda hill area in Guntur Dist,and Tirumala in Chittur District, A.P. Indian soils are best for alkaline protease producing bacteria that resulted in isolation of 21 alkaline protease producing alkaliphilic bacterial strains. MS6 showed the highest production (110U/ml) after 48h. This isolate was identified as Bacillus licheniformis by Microbial Type Culture Collection center (MTCC) and gene bank, Institute of Microbial Technology (IMTECH), Chandigarh, India. This strain was used to examine the changes in alkaline protease production following UV irradiation. Induction of mutation in Bacillus licheniformis strain was carried out by 0, 3, 6, 9, 12, 15, 18 and 20 min with 30-W germicidal lamp that has radiation at 2540 - 2550A 0 at a distance of 15cm in dark and irradiated. A total of 17 mutants were selected. They were designated as Bl1 to Bl9 and Bl10 to Bl17. Among these only three strains viz., Bl2, Bl11, and Bl16 did exhibit high efficiency in production on the basis of relative growth production (C/G). Of the seventeen mutants of Bacillus licheniformis, ten were chosen to assay their productivity. Mutants no Bl8, Bl3, Bl16 were the most effective in enzyme production under submerged conditions being 180, 140,128U/ml respectively. Results revealed that alkaline protease activity assay under submerged culture conditions was more accurate than the relative growth production (C/G) method because there is no correlation between zone diameter and the ability to produce the enzyme in submerged cultures. High level of productivity increased with Bl8 mutant of B.licheniformis, indicating that the enzyme is to be thermo-alkaliphilic protease.

Fermentation, Isolation, Structure, and Antidiabetic Activity of NFAT-133 produced by Streptomyces strain PM0324667

Type-2 diabetes is mediated by defects in either insulin secretion or insulin action. In an effort to identify extracts that may stimulate glucose uptake, similar to insulin, a high throughput-screening assay for measuring glucose uptake in skeletal muscle cells was established. During the screening studies to discover novel antidiabetic compounds from microbial resources a Streptomyces strain PM0324667 (MTCC 5543, the Strain accession number at Institute of Microbial Technology, Chandigarh, India), an isolate from arid soil was identified which expressed a secondary metabolite that induced glucose uptake in L6 skeletal muscle cells. By employing bioactivity guided fractionation techniques, a tri-substituted simple aromatic compound with anti-diabetic potential was isolated. It was characterized based on MS and 2D NMR spectral data and identified as NFAT-133 which is a known immunosuppressive agent that inhibits NFAT-dependent transcription in vitro. Our investigations revealed the antidiabetic potential of NFAT-133. The compound induced glucose uptake in differentiated L6 myotubes with an EC50 of 6.3 ± 1.8 μM without activating the peroxisome proliferator-activated receptor-γ. Further, NFAT-133 was also efficacious in vivo in diabetic animals and reduced systemic glucose levels. Thus it is a potential lead compound which can be considered for development as a therapeutic for the treatment of type-2 diabetes. We have reported herewith the isolation of the producer microbe, fermentation, purification, in vitro, and in vivo antidiabetic activity of the compound.

In vitro antibacterial activity of fronds (leaves) of some important pteridophytes

The main objective of this research work is to screen various unexploited plants for their antimicrobial activity as these unexploited or pteridophytic plants are being used ethanomedicinally but, very little work has been done on their antimicrobial aspects. So, to explore the efficacy of these plants, the following research has been carried out. Bacterial strains of Agrobacterium tumefaciens, Escherichia coli, Salmonella arizonae, Salmonella typhiand Staphylococcus aureus were procured from the Institute of Microbial Technology (IMTECH), Chandigarh and the aqueous and alcoholic leaves extract of twelve important pteridophytic plants were prepared and tested for their antimicrobial activity against the bacteria selected by Disc diffusion method as suggested by Bauer et al. (1966). It has been observed that, nearly all the leaves extracts have shown inhibitory effect against the bacterial strains selected and some of the extracts were more competent than the selected antibiotic. Our findings provide the novel insights with regards to antimicrobial agents and these could be further enhanced through in vivo studies and isolation and characterization of active constituents for human health. In the present scenario, the use of herbs and herbal medicine is at its peak and majority of researchers are screening higher plants for the same but, very few researchers are considering the lower plants for their antimicrobial potential. Since, these pteridophytic plants are considered to be the disease free plants and are being used ethanobotanically by various tribal communities. These plants are further screened for their in vivo potential as well as for their drug properties. Key words: Antimicrobial activity, pteridophytic plants, leaves extracts, bacteria.

Characterization and phylogenetic analysis of an entomopathogenic Bacillus cereus strain WGPSB-2 (MTCC 7182) isolated from white grub, Anomala dimidiata (Coleoptera: Scarabaeidae)

White grubs (Coleoptera: Scarabaeidae) are cosmopolitan and polyphagous insect pests of agricultural crops, forests and pastures around the world. The lack of an environmentally sound approach for white grub management has prompted the exploration and detection of a novel microbial biocontrol agent against these sub-terranean insect pests. In this study we describe the isolation, establishment of pathogenesis, biochemical characterization and phylogenetic analysis of an entomopathogenic Bacillus cereus strain WGPSB-2 (MTCC 7182), isolated from an atrophied pupa of Anomala dimidiata, collected from the N.W. Indian Himalayas. The sequencing and subsequent comparison of the 16S rDNA revealed that the strain has100% similarity with Bacillus cereus sequences. Phylogenetic analysis of the 16S rDNA sequence revealed that the isolate is closely related to Bacillus thuringiensis and Bacillus sphaericus. In vitro bioassays showed that the isolate was able to infect and cause 92 and 67% mortality in second instar larvae of Anomala dimidiata and Holotrichia seticollis, respectively. The infected larvae exhibited bacterial septicemia like symptoms and mortality occurred between the third and ninth weeks after inoculation. The culture has been granted the accession number MTCC 7182 by the Microbial Type Culture Collection and Gene Bank, Institute of Microbial Technology, Chandigarh, India.

PDSB: Public Domain Software in Biology

Biotech Software & Internet ReportVol. 2, No. 4 Software ReviewsPDSB: Public Domain Software in BiologyG. P. S. RaghavaG. P. S. RaghavaSearch for more papers by this authorPublished Online:5 Jul 2004https://doi.org/10.1089/152791601753204313AboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail FiguresReferencesRelatedDetailsCited byComputational Methods in Genome Research Volume 2Issue 4Sep 2001 To cite this article:G. P. S. Raghava.PDSB: Public Domain Software in Biology.Biotech Software & Internet Report.Sep 2001.154-156.http://doi.org/10.1089/152791601753204313Published in Volume: 2 Issue 4: July 5, 2004PDF download

Cr(VI) Reduction by Bacillus coagulans Isolated from Contaminated Soils

Investigation on Cr(VI) reduction was conducted using bacteria isolated from soil samples receiving electroplating wastewater. Chromium reduction capacity of these isolates was compared with that of Pseudomonas aeruginosa, a pure culture procured from the Institute of Microbial Technology, as well as Bacillus circulans, a laboratory isolate from garden soil. Bacillus coagulans, isolated and identified from chromium polluted soil, gave maximum reduction potential among all organisms studied. Malate was found to yield maximum biotransformation out of four electron donors employed. B. coagulans was able to reduce Cr(VI) even at 10 mM initial Cr(VI) concentration. With an increase in initial cell density, Cr(VI) reduction capacity was also increased; however, maximum specific biotransformation occurred at low cell densities. The optimum pH for Cr(VI) reduction was 7. Sulphates and nitrates did not compete with Cr(VI) for accepting the electrons. The presence of respiratory inhibitors like DNP and NaN3 margina...

A rejoinder to the commentary on ‘Thermostability of B-xylosidase from Aspergillus sydowii MG49’ by M. Ghosh and G. Nanda, FEBS Letters 330 (1993) 275–278 by D. Ananthapadmanavan (Institute of Microbial Technology, Chandigarh, India)

A rejoinder to the commentary on ‘Thermostability of B-xylosidase from Aspergillus sydowii MG49’ by M. Ghosh and G. Nanda, FEBS Letters 330 (1993) 275–278 by D. Ananthapadmanavan (Institute of Microbial Technology, Chandigarh, India)

Sphingobacterium antarcticus sp. nov., a Psychrotrophic Bacterium from the Soils of Schirmacher Oasis, Antarctica

Two pure cultures of bacteria isolated from soil samples collected in Schirmacher Oasis, Antarctica, conformed to the definition of the genus Sphingobacterium. They differed from all of the known species of Sphingobacterium in being psychrotrophic. The G+C contents of the DNA of the two strains were found to be 39.3 and 40.3 mol%, and DNA-DNA hybridization studies indicated 7% homology with S. multivorum and S. spiritivorum. The name Sphingobacterium antarcticus sp. nov. is proposed for the two Antarctic strains. The type strain is 4BY (MTCC 675), and it has been deposited with the Microbial Type Culture Collection, Institute of Microbial Technology, Chandigarh, India.