http://nopr.niscair.res.in/handle/123456789/1493 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/4169 Title: Removal of polycyclic aromatic hydrocarbons from aqueous media by themarine fungus NIOCC # 312: involvement of lignin-degrading enzymes and exopolysaccharides <br/> <br/>Authors: Raghukumar, Chandralata; Shailaja, M.S.; Parameswaran, P.S.; Singh, S.K. <br/> <br/>Abstract: The removal of polycyclic aromatic hydrocarbons from aqueous culture medium by the lignin-degrading marine fungus NIOCC # 312, obtained from decaying seagrass from a coral reef lagoon is reported here. We estimated the percentage of phenanthrene removed from the culture supernatant and the fungal biomass after 6 days. About 60-70% of phenanthrene, at a concentration of 12 mg l^-1 (12 ppm) was removed from the culture medium containing live or heat-killed fungus, as estimated by fluorescence spectroscopy method. Nuclear magnetic resonance spectra of the phenanthrene extracted from the fungal biomass revealed that in the heat-killed fungal biomass, the phenanthrene remained undegraded till day 6. On theother hand in the live fungal biomass, no phenanthrene was detected on day 6 suggesting that it was metabolized or transformed into non-aromatic fragments. We conclude that the disappearance of phenanthrene from the aqueous culture medium is due to its instant adsorption to the fungal biomass owing to the presence of the exopolymeric substance (EPS) around the fungal hyphae. The EPS produced by the fungus was partially characterized. We further hypothesize that phenanthrene thus adsorbed by the live fungal biomass was subsequently degraded by the lignin-degrading enzymes present in the cell wall and the EPS envelope. Thus, the heat-killed fungal biomass could be used only for adsorption of PAHs from contaminated sites whereas use of the live fungal biomass would result in degradation of PAHs. <br/> <br/>Page(s): 373-379 Tue, 28 Nov 2006 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1538 Title: Marine microbial eukaryotic diversity, with particular reference to fungi: Lessons from prokaryotes <br/> <br/>Authors: Raghukumar, Seshagiri <br/> <br/>Abstract: Novel molecular, analytical and culturing techniques have resulted in dramatic changes in our approaches towards marine eukaryotic diversity in recent years. This article reviews marine fungal diversity in the light of current knowledge, citing examples of how progress in understanding marine prokaryotes has often contributed to this new approach. Both ‘true fungi’ (termed mycenaean fungi in this review) and straminipilan fungi are considered. Molecular phylogenetic studies of prokaryotes has resulted in their redefinition as belonging to the Kingdoms Bacteria and Archaea. Likewise, major refinements have taken place in the phylogenetic classification of eukaryotes. In the case of fungi, it has now been realized that they are polyphyletic, belonging to the Kingdom Mycenae (Fungi), as well as the Kingdom Straminipila or Chromista. Although the total number of fungi on earth is estimated to be about 1.5 million, only a meagre number of obligate marine fungi , about 450 mycenaean and 50 straminipilan fungi have been described so far. It is likely that most of the true marine fungi have not yet been discovered. These are likely to have evolved between 1,500 million years ago (Ma) when fungi probably evolved in the sea and 900 Ma when they conquered land together with green plants. It now appears that most of the true marine fungi have not been cultured so far, similar to the ‘great plate count anomaly’ of bacteria. Thraustochytrids, which are abundant in the water column, but not easily culturable from that source is an example. Intelligent and novel culture methods might bring forth unusual and new marine fungi, as happened in the case of Pelagibacter ubique belonging to the SAR 11 group of bacteria. Molecular techniques might bring to light novel marine fungi, as is happening with bacteria. Such fungi may defy our conventional wisdom regarding these organisms in terms of morphology. Thus, several recent studies using 18S rRNA gene community profiles have discovered picoplanktonic marine fungi in the water column. Studies such as those on molecular diversity of eukaryotes in permanently anoxic habitats have also indicated that fungi may be abundant in exotic habitats and possess unusual physiology. A search for fungi in biodiversity-rich habitats, such as the coral reefs and the deep-sea, using a combination of molecular and novel culture methods is likely to reveal a fascinating diversity of marine fungi. <br/> <br/>Page(s): 388-398 Tue, 28 Nov 2006 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1537 Title: A review on fungal diseases of algae, marine fishes, shrimps and corals <br/> <br/>Authors: Ramaiah, N. <br/> <br/>Abstract: It is a well-known fact that diseases affect health, survival and recruitment of any individual susceptible for diseases. As a consequence of disease, harvests from natural resources and, in particular, those from aquaculture dwindle quite severely. While an appreciable volume of information on variety of mycotic diseases in the marine organisms is available on global scale, studies from Indian waters are, at best, very few. This review is an attempt of bringing together a set of information deemed useful for stimulating marine mycopathological investigations in our waters. The information put together here is also to highlight the importance of pathology in general and fungal diseases in particular. <br/> <br/>Page(s): 380-387 Tue, 28 Nov 2006 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/1536 Title: Effect of nutrient nitrogen on laccase production, its isozyme pattern and effluent decolorization by the fungus NIOCC #2a, isolated from mangrove wood <br/> <br/>Authors: D’Souza-Ticlo, Donna; Verma, Ashutosh Kumar; Mathew, Meril; Raghukumar, Chandralata <br/> <br/>Abstract: Carbon and nitrogen sources in the growth medium play an important role in the production of lignin-degrading enzymes in the white-rot basidiomyceteous fungi. The role of nutrient nitrogen sources in growth media on production of lignin-degrading enzymes namely laccase, lignin peroxidase and manganese peroxidase as well as on the decolorization of industrial effluents like black liquor, molasses spent wash and textile mill effluents was studied using the basidiomycetous fungus NIOCC #2a isolated from mangrove wood. The results indicated that the type of nitrogen source used, not only influences the amount and type of lignin-degrading enzymes produced but also has an effect on the decolorization of these effluents. The amount of extracellular peroxidases increased by several fold in the presence of effluents whereas in their absence they were of negligible quantity. Some of the effluents had an inhibitory effect on laccase production. The effect of nitrogen sources in the absence as well as presence of the effluents, on the expression of laccase isoenzymes was studied by non-denaturing SDS-PAGE. It was noticed that a few new isozymes of laccase were induced in the presence of industrial effluents. Decolorization of these effluents by the concentrated culture filtrate obtained from media containing different nitrogen sources further proved the importance of the type of nitrogen source in decolorization of colored industrial effluents. <br/> <br/>Page(s): 364-372 Tue, 28 Nov 2006 22:58:59 GMT