The presence or absence of fucose, galactose, rhamnose, and xylose as well as the ratio of glucose to mannose after hydrolysis of purified yeast cell walls are valuable characters to assign yeasts or yeast states of Ascomycetes and Basidiomycetes phylogenetically. The coupling of pellicular anion-exchange resins (Dionex CarboPac PA-1) with pulsed amperometric detection provides a simple, quick, selective, and sensitive method for the analysis of yeast cell wall carbohydrates. Phragmobasidial smut fungi of monocotyledonous (Ustilago s. str., Sporisorium) and dicotyledonous (Microbotryum, Sphacelotheca) host plants cluster in two different, phylogenetically distinct yeast types, the Microbotryum type and the Ustilago type. In contrast, all smut fungi with simple holobasidia (Entyloma, Melanotaenium) from monocots and dicots investigated so far, exhibit a cell wall carbohydrate spectrum characteristic for the Ustilago type. Ustilentyloma fluitans, although a phragmobasidial smut fungus on grasses, whose smut spores and parasitic symptoms resemble Entyloma species, display the neutral sugar pattern of the Microbotryum type. The close phylogenetic relationship between the Graphiolales, Ustilaginales s. str. (phragmobasidial smuts of monocots), and Exobasidiales was substantiated further by additional strains. The presence of xylose and balanced amounts of glucose and mannose is characteristic for yeast states of the Dacrymycetaceae. The production of extracellular amyloid compounds (EAC) as well as the cell wall carbohydrate pattern point to a Tremella type affinity of Atractogloea stillata, Itersonilia perplexans, and Sterigmatosporidium polvmorphum. A meiosporangial evolution starting from coccal yeast basidia (Sterigmatosporidium) via transversely (auricularioid) septate (Atractogloea) to longitudinally divided phragmobasidia (Tremella) and simple holobasidia (Cystofilobasidium) was substantiated further within the Tremella type. The complex holobasidia (Collybia) of the Homobasidiomycetes evolved polyphyletically from longitudinally septate phragmobasidia via partially divided holobasidia (Carcinoryces). On the basis of the cell wall carbohydrate composition of approximately 250 yeasts and yeast stages of Ascomycetes and Basidiomycetes, seven distinct yeast types are described and interpreted phylogenetically.
Seasonal variations in bacterial populations and their antibiotic sensitivity were surveyed in the water of the river Gomati at Lucknow. Most of the bacteria showed an increase in their densities in sewage-contaminated downstream of the river during summer. In contrast, Aeromonas sp. count was found to be higher in upstream during winter. Vibrio cholerae non-01 was substantially found in downstream only. More than half of the bacterial isolates exhibited antibiotic resistance. The maximum resistance was shown by the winter isolates (36%), particularly from downstream (77.7%). Among the resistant isolates, resistance for ampicillin was predominant (42%), followed by tetracycline (40%). Single and multiple antibiotic resistances were the highest among 32% and 47% of aeromonads, respectively. The double resistance was exhibited to be maximum by the vibrio non-01 isolates. Disposal of municipal sewage with fecal wastes seems to be mainly responsible for deterioration of water quality along with increased population of pathogenic and antibiotic resistant bacteria in river.
The role of glutamine synthetase (GS), glutamine and/or NH4+ in the regulation of glutamine uptake was studied in the cyanobacterium Anabaena cycadeae and its glutamine auxotrophic mutant lacking GS activity. The uptake pattern was found to be biphasic in both the strains consisting of an initial rapid phase lasting up to 60s followed by a slower second phase. The glutamine uptake was found to be maximum in glutamine medium whereas the cells incubated in N2 and NO3- media showed similar uptake activities in both wild-type and mutant strain. The glutamine uptake system was found to be NH4+-repressible. NH4+ and glutamine did not inhibit the glutamine uptake in the glutamine auxotrophic mutant lacking GS activity, suggesting that NH4+ and glutamine are not the repressor signals for glutamine uptake. The glutamine auxotrophic mutant also had higher level of glutamine uptake as compared to wild-type strain, indicating that GS activity is not necessarily involved in the uptake process of glutamine. Azaserine, an inhibitor of glutamate synthase (GOGAT), effectively inhibited the glutamine uptake in both the strains. Thus, it is suggested that the increased intracellular glutamine level regulates its own uptake in the cyanobacterium Anabaena cycadeae.
The cell surface charge of 101 strains of bacteria isolated from grassland soil was examined by determining the electrophoretic mobility (EPM) of the cells. The isolates were cultured in diluted nutrient broth medium at 27°C and the EPM of the cells was measured by micro-electrophoresis in 10mM phosphate buffer solution at 25°C as a function of pH varying from 3.1 to 9.0. All the isolates showed negative EPM values at pH 7. These values varied characteristically among strains, i.e., slow-growing isolates showed a lower level of negative EPM values compared with fast-growing isolates. The EPM of each strain did not greatly differ from pH 9 to 6, whereas it showed a lower level of negative values under more acidic conditions. This change in the EPM value was smaller for the slow-growing isolates than that for the fast-growing ones. Under the most acidic condition (pH 3.1), some isolates, mostly the fastest-growing, Gram-positive bacteria, showed positive EPM values. The above detailed changes in EPM suggest that the fast-growing isolates have a greater number of acidic groups at the cell surface, compared with the slow-growing isolates. Furthermore, the finding of positive EPM values for the fastest-growing bacteria indicates the existence of some basic groups at their cell surface.
Four γ-polyglutamate (γ-PGA)-producing Bacillus strains were isolated from a "dan-douchi" in China, all of which indicated biotin requirement for growth and a considerably high γ-glutamyltranspeptidase (γ-GTP) productivity. These strains carried a single plasmid species, and their molecular sizes and restriction patterns differed completely. Some of HindIII DNA fragments of "dan-douchi" plasmids strongly hybridized with a 1.7-kb TaqI DNA fragment of "natto" plasmid, pUH1, which encodes γ-GTP gene responsible for γ-PGA production, and their molecular sizes of homologous fragments were found to be similar. The hybridization analysis revealed that the structure gene of γ-GTP encoded on "dan-douchi" plasmid was found to greatly resemble that on "natto" plasmid. Furthermore, "dan-douchi" plasmid had a high degree of homology with DNA segment encoding the replication protein of pUH1. These results, therefore, strongly suggest that "dan-douchi" plasmid might be a functional plasmid as well as "natto" plasmid, and it should be considered that both "natto" and "dan-douchi" plasmids might develop from a common ancestral molecule.
To investigate changes of protein profiles and appearance of a lectin during fruit body formation in basidiomycete, Pleurotus cornucopiae, the developmental process was divided into four stages: the vegetatively growing mycelium, the primordium, the immature and the mature fruit body. Hemagglutinating activity was not found in the vegetative mycelium but the activity started to appear in the primordium, and continued to increase during the fruit body formation. A protein cross-reactive with anti-lectin serum also appeared after the primordium formation, indicating that the synthesis of the lectin in P. cornucopiae was developmentally regulated.
The endochitinase from the culture filtrate of Myrothecium verrucaria was purified by ultrafiltration using an Amicon PM-10 membrane and preparative polyacrylamide gel electrophoresis at pH 8.9. The purified enzyme showed a single protein band in SDS gel electrophoresis and polyacrylamide gel electrophoresis run at pH 8.9, 4.3 and 2.9. Isoelectric focusing in the pH range of 3.5-10.0 in 7.5% polyacrylamide gel also revealed a single protein band. The enzyme had an average molecular weight of 30, 000 as estimated from SDS gel electrophoresis and gel filtration studies. The optimum pH and temperature using ethylene glycol chitin as a substrate were 5.0 and 50°C, respectively. The enzyme showed maximum activity towards carboxymethyl chitin and ethylene glycol chitin as compared to colloidal chitin. The apparent Km (mg/ml) was 1.33 and 2.85 for ethylene glycol chitin and carboxymethyl chitin, respectively. A Vmax (μmol NAG equivalents/min/μmol of enzyme) of 2.904×103 and 7.67× 103 was estimated for ethylene glycol chitin and carboxymethyl chitin, respectively. The viscometric studies using carboxymethyl chitin (0.2%) revealed endotype action for the purified enzyme.
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Edited and published by : Applied Microbiology, Molecular and Cellular Biosciences Research Foundation/Center for Academic Publications Japan Produced and listed by : TERRAPUB, Center for Academic Publications Japan/Shobi Printing Co., Ltd. (-Vol.60,No12), Center for Academic Publications Japan/InternationalAcademic Printing Co., Ltd.(-Vol.54,No1)