Publications

Type : Full Length Research Article; Journal / Book : Keanean Journal of Sciences; Volume : 1; Pages : 21-32;
Publisher : IQAC, Lady Keane College, Shillong; Place Published : Shillong;
Date : Dec, 2012 ISBN/ISSN : 0000-0000;

Preliminary screening and compositional analysis of bacterial biofilm from hypogean environments of Meghalaya, India 

  • Subhro Banerjee
  • Santa Ram Joshi

Abstract

Hypogean environments comprising of caves and subterranean habitats have long been recognized as a nutrient-deficient environment. To overcome limitation, selfish competition for resources is replaced by cooperative and mutualistic microbial associations of which biofilm formation is a phenomenon. The hypogean habitats in the form of caves in Meghalaya are diverse and some are among the largest in Asia. These caves have so far not yet attracted much attention of geomicrobiologists. On a preliminary scale, two different caves were selected for study of bacterial biofilm at different distances from the cave entrance. A total of 18 different morphotypes of bacteria were obtained from Mawsmai cave and 8 from Mawmluh cave. Moreover, as extracellular substrates can be converted into exopolysachharide of   biofilm bacteria by secreted enzymes, e.g., glucansucrase (which have applications in various industries like pharmaceutical, food, cosmetic, agricultural, photography and mining), we also attempted to screen the most potential glucansucrase producing bacterium from the isolates.

Keywords : Bacteria, biofilm, cave, glucansucrase
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Url : http://keaneanjournalofscience.in/?p=106
Type : Full Length Research Article; Journal / Book : African Journal of Microbiology Research; Volume : 4; Issue Number : 23; Pages : 2534-2542;
Publisher : ACADEMIC JOURNALS; Place Published : Victoria Island, Lagos, Nairobi;
Date : Nov, 2010 ISBN/ISSN : 1996-0808;

Thermostable -amylase from natural variants of Bacillus spp. prevalent in eastern Himalayan Range

  • Lamabam Sophiya Devi
  • Polashree Khaund
  • Santa Ram Joshi

Abstract

North Eastern Region of India in the eastern Himalayan Range has a rich diversity of microbial flora which has remained unexplored. It is thus, an ideal place to explore the rich and complex microbial diversity for the isolation of novel -amylase enzyme. In the present study, various bacterial strains were isolated from soils of North-Eastern region of India spread over diverse habitats ranging from an altitude of 24 to 3855 msl. Thirty bacterial isolates were screened for -amylase production by plate assay method. Sixteen such strains were found to be positive for amylase production on starch agar medium. The amylase activity was assayed by DNSA method at different time intervals (10 - 60 min). Two bacterial strains (MK8 and MA9) were selected for further assays based on their higher enzyme activity. Based on the morphological, physiological and biochemical characteristics and phylogenetic position as determined by 16S ribosomal DNA gene sequencing, the bacterial strains MK8 and MA9 were identified as Bacillus cereus and Bacillus subtilis respectively. The optimum activity in shake-flask cultures was seen between 30 - 40 min of incubation and the maximum enzyme production was achieved during the stationary phase (36 - 48 h) of the growth of the organism. Bacterial cultures in stationary phase were taken for enzyme activity assay and the incubation time was optimized at 30 min based on the optimal activity. The maximal -amylase activity was achieved at 60oC, pH 7 and 80 oC, pH 6 - 8 for MA9 and MK8, respectively. The amylase of MK8 strain remained stable between 30° and 80°> C C, whereas, in case of MA9 strain, the amylase was found to be stable between 30 and 60° This indicates C. that the enzyme produced by MA9 strain is moderately thermostable while that of the MK8 strain is highly thermostable. Ca enhanced the -amylase activity of the MA9 strain whereas in case of MK8 strain, addition of Ca did not show any significant increase in amylase activity. Pb had highe inhibition of enzyme activity compared to Cd , Cr and Zn . Nearly 100% was recovered with Cu addition in case of MA9 strain but only 50% was recovered for MK8 strain.

Keywords : amylase, screening, thermostable, optimization, Bacillus.
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Url : http://www.academicjournals.org/ajmr/abstracts/abstracts/abstracts2010/4Dec/Devi%20et%20al.htm
Type : Full Length Research Article; Journal / Book : Mycobiology; Volume : 40; Issue Number : 1; Pages : 27-34;
Publisher : The Korean Society of Mycology; Place Published : Seoul, Korea;
DOI : 10.5941/MYCO.2012.40.1.027; Date : Mar, 2012 ISBN/ISSN : 1229-8093;

Antimicrobial and synergistic effects of silver nanoparticles synthesized using soil fungi of high altitudes of eastern himalaya.

  • Lamabam Sophiya Devi
  • Santa Ram Joshi*

Abstract

Fifty three fungi isolated from soils of different microhabitats of eastern Himalayan range (3,400~3,600 msl) were screened for mycosynthesis of silver nanaoparticles (AgNPs) and their efficacy as antimicrobials were assessed in combination with commonly used antibiotics. Three isolates Aspergillus terreus SP5, Paecilomyces lilacinus SF1 and Fusarium sp. MP5 identified based on morphological and 18S rRNA gene sequences were found to synthesize AgNPs. These nanoparticles were characterized by visual observation followed by UV-visible spectrophotometric analysis. The AgNPs synthesized by Aspergillus terreus SP5, Paecilomyces lilacinus SF1 and Fusarium sp. MP5 showed absorbance maxima at 412, 419, and 421 nm respectively in the visible region. Transmission electron microscopy micrograph showed formation of spherical AgNPs of 5~50 nm size. The antimicrobial activity of the mycosynthesized nanoparticles were investigated alone and in combination with commonly used antibiotics for analysis of growth inhibition zone against test organisms, namely, Staphylococcus aureus MTCC96, Streptococcus pyogenes MTCC1925, Salmonella enterica MTCC735 and Enterococcus faecalis MTCC2729. The mycosynthesized nanoparticles showed potent antibacterial activity and interestingly their syngergistic effect with erythromycin, methicillin, chloramphenicol and ciprofloxacin was significantly higher as compared to inhibitions by AgNPs alone. The present study indicates that silver nanoparticles synthesized using soil borne indigenous fungus of high altitudes show considerable antimicrobial activity, deserving further investigation for potential applications.

Keywords : Antibiotics, Antimicrobial activity, Fungal isolates, High altitudes, Silver nanoparticles, Synergy
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Url : http://www.ncbi.nlm.nih.gov/pubmed/22783131
Type : Full Length Research Article; Journal / Book : Proceedings of the National Academy of Sciences, India Section B: Biological Sciences;
Publisher : Springer-Verlag;
DOI : 10.1007/s40011-013-0185-7; Date : Nov, -0001 ISBN/ISSN : 0369-8211;

Studies on Biosynthesis of Antimicrobial Silver Nanoparticles Using Endophytic Fungi Isolated from the Ethno-medicinal Plant Gloriosa superba L.

  • Lamabam Sophiya Devi
  • Donald A. Bareh
  • Santa Ram Joshi

Abstract

Two endophytic fungi isolated from the ethno-medicinal plant Gloriosa superba L. were used for the in vitro biosynthesis of silver nanoparticles (AgNPs). The endophytic fungi were identified as Alternaria solani GS1 and Penicillium funiculosum GS2 based on their ITS regions of rRNA gene sequences. The silver nanoparticles obtained were characterized by UV–visible spectroscopy and transmission electron microscopy. Silver nanoparticles of the size 5–20 nm biosynthesized by A. solani GS1were found to be at peak at 415 nm whereas the AgNPs of the size 5–10 nm biosynthesized using P. funiculosum GS2 showed a maximum peak at 403 nm. An evident superiority of the antimicrobial potency, as denoted by the zone of inhibition by biosynthesized AgNPs using P. funiculosum GS2 compared to that by A. solani GS1, was observed when the nanoparticles were used against three different bacterial strains (Streptococcus pyogenes MTCC1925, Escherichia coli MTCC730 and Enterococcus faecalis MTCC2729) and a fungal strain (Candida albicans MTCC183). The present study elucidates the efficacy of the AgNPs synthesized by endophytic fungi against the three tested bacterial strains as well as the fungal strain C. albicans indicating their potency of bioprospection for medicinal usage.

Keywords : Endophytic fungi, Penicillium funiculosum Alternaria solani, Silver nanoparticles, Antimicrobial activity
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Url : http://link.springer.com/article/10.1007%2Fs40011-013-0185-7
Type : Full Length Research Article; Journal / Book : Mycobiology; Volume : 40; Issue Number : 3; Pages : 151-158;
Publisher : The Korean Society of Mycology; Place Published : Seoul, Korea;
DOI : 10.5941/MYCO.2012.40.3.151; Date : Sep, 2012 ISBN/ISSN : 1229-8093;

Diversity of Culturable Soil Micro-fungi along Altitudinal Gradients of Eastern Himalayas  

  • Lamabam Sophiya Devi
  • Polashree Khaund
  • Fenella M. W. Nongkhlaw and Santa Ram Joshi*

Abstract

Very few studies have addressed the phylogenetic diversity of fungi from Northeast India under the Eastern Himalayan range. In the present study, an attempt has been made to study the phylogenetic diversity of culturable soil fungi along the altitudinal gradients of eastern Himalayas. Soil samples from 24 m above sea level to 2,000 m above sea level altitudes of North-East India were collected to investigate soil micro-fungal community structure and diversity. Molecular characterization of the isolates was done by PCR amplification of 18S rDNA using universal primers. Phylogenetic analysis using BLAST revealed variation in the distribution and richness of different fungal biodiversity over a wide range of altitudes. A total of 107 isolates were characterized belonging to the phyla Ascomycota and Zygomycota, corresponding to seven orders (Eurotiales, Hypocreales, Calosphaeriales, Capnodiales, Pleosporales, Mucorales, and Mortierellales) and Incertae sedis. The characterized isolates were analysed for richness, evenness and diversity indices. Fungal diversity had significant correlation with soil physico-chemical parameters and the altitude. Eurotiales and Hypocreales were most diverse and abundant group of fungi along the entire altitudinal stretch. Species of Penicillium (D = 1.44) and Aspergillus (D = 1.288) were found to have highest diversity index followed by Talaromyces (D = 1.26) and Fusarium (D = 1.26). Fungal distribution showed negative correlation with altitude and soil moisture content. Soil temperature, pH, humidity and ambient temperature showed positive correlation with fungal distribution.

Keywords : Altitude, Diversity indices, Microfungal diversity, Richness, 18S rDNA
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Url : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3483390/

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