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71.
M. Y. Shukor M. F. Rahman Z. Suhaili N. A. Shamaan M. A. Syed 《World journal of microbiology & biotechnology》2009,25(7):1225-1234
A bacterium that was able to tolerate and reduce as high as 50 mM of sodium molybdate to molybdenum blue has been isolated
from a metal recycling ground. The isolate was tentatively identified as Serratia sp. strain Dr.Y8 based on the carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny.
ANOVA analysis showed that isolate Dr.Y8 produced significantly higher (P < 0.05) amount of Mo-blue with 3, 5.1 and 11.3 times more molybdenum blue than previously isolated molybdenum reducers such
as Serratia
marcescens strain Dr.Y6, E. coli K12 and E. cloacae strain 48, respectively. Its molybdate reduction characteristics were studied in this work. Electron donor sources such as
sucrose, mannitol, fructose, glucose and starch supported molybdate reduction. The optimum phosphate, pH and temperature that
supported molybdate reduction were 5 mM, pH 6.0 and 37°C, respectively. The molybdenum blue produced from cellular reduction
exhibited a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Metal ions such as chromium,
silver, copper and mercury resulted in approximately 61, 57, 80, and 69% inhibition of the molybdenum-reducing activity at
1 mM, respectively. The reduction characteristics of strain Dr.Y8 suggest that it would be useful in future molybdenum bioremediation. 相似文献
72.
73.
The study presents a mathematical function describing a correlation between the amount of ergosterol and the number of colony-forming units (CFU) of mould contaminating selected building materials such as: a block of cellular concrete, gypsum—carton board and gypsum—carton board covered with emulsion paint. The dependence obtained for a particular material as well as an average dependence for all the investigated materials has been described by means of an exponential equation. It has been found out that there is high, statistically significant correlation between ergosterol content and CFU number of mould in all of the building materials. The correlation coefficients have ranged from r=0.790 to 0.933. The elaborated equation describing the above dependence can be applied to estimate mould contamination by means of culture methods within the range 103–108 CFU/m2 of the surface. In addition, the estimated level of ergosterol in these materials has been shown to be the criterion by which to evaluate the degree of filamentous fungal contamination. It has been assessed that an ergosterol content exceeding the level of 3.96 mg/m2 indicates the active development of mould. This criterion has been applied to evaluate several building materials i.e.: concrete, gypsum board, emulsion coatings, brick, plaster, wallpaper, glass wool, mineral wool and wood. No statistically significant differences have been observed between CFU number of mould calculated from a model equation on the basis of the ergosterol content and CFU number of mould experimentally determined by traditional methods. The results presented in this paper show that the elaborated equation of correlation between the ergosterol content and CFU number of mould can be applied to estimate mould contamination of different building materials, based on the determination of ergosterol. 相似文献
74.
75.
76.
F. MONTEALEGRE‐Z 《Journal of evolutionary biology》2009,22(2):355-366
Male katydids (Orthoptera: Tettigoniidae) produce mating calls by rubbing the wings together, using specialized structures in their forewings (stridulatory file, scraper and mirror). A large proportion of species (ca. 66%) reported in the literature produces ultrasonic signals as principal output. Relationships among body size, generator structures and the acoustic parameters carrier frequency (fc) and pulse duration (pd), were studied in 58 tropical species that use pure‐tone signals. A comparative analysis, based on the only available katydid phylogeny, shows how changes in sound generator form are related to changes in fc and pd. Anatomical changes of the sound generator that might have been selected via fc and pd are mirror size, file length and number of file teeth. Selection for structures of the stridulatory apparatus that enhance wing mechanics via file‐teeth and scraper morphology was crucial in the evolution of ultrasonic signals in the family Tettigoniidae. 相似文献
77.
Two Saccharomyces cerevisiae strains with different degrees of ethanol tolerance adapted differently to produced ethanol. Adaptation in the less ethanol-tolerant
strain was high and resulted in a reduced formation of ethanol-induced respiratory deficient mutants and an increased ergosterol
content of the cells. Adaptation in the more ethanol-tolerant strain was less pronounced. Journal of Industrial Microbiology & Biotechnology (2000) 24, 75–78.
Received 22 June 1999/ Accepted in revised form 06 October 1999 相似文献
78.
Biological responses of tight junction to ionizing radiation and electromagnetic field expostion. 总被引:1,自引:0,他引:1
Z Somosy G Bognár G Thuróczy G J K?teles 《Cellular and molecular biology, including cyto-enzymology》2002,48(5):571-575
The tight junctions form and regulate the paracellular barrier in the intercellular spaces between epithelial and endothelial cells. They play important roles in the cellular and pathological processes, which follow exposure to radiation. Therefore, analysis of their changes upon different kind of irradiation may help to understand the basic events governing their function and give important information for the radiobiological research and clinical practice as well. The immunohistochemical data on the distribution of occludin presented here demonstrate the breakdown of tight junctions in Madin Darby kidney cells exposed to ionizing irradiation and show, on the other hand that magnetic field exposures upon 100 microT leave the occludin staining pattern intact. 相似文献
79.
80.
The ‘benefits of philopatry’ hypothesis states that helpers in cooperatively breeding species derive higher benefits from
remaining home, instead of dispersing and attempting to breed independently. We tested experimentally whether dispersal options
influence dispersal propensity in the cooperatively breeding Lake Tanganyika cichlids Neolamprologus pulcher and N. savoryi. Cooperative groups of these fishes breed in densely packed colonies, surrounded by unoccupied, but apparently suitable breeding
habitat. Breeding inside colonies and living in groups seems to benefit individuals, for example by early detection and deterrence
of predators. We show that despite a slight preference of both species for habitat with a higher stone cover, 40% of the preferred
habitat remained unoccupied. On average, the colonies contained a higher number of (1) predators of adults, juveniles and
eggs, (2) shelter competitors, and (3) other species including potential food competitors, compared to the outside colony
habitat. Apparently, habitat differences cannot explain why these cichlids breed in colonies. Accordingly, dispersal may not
be limited by a lack of suitable breeding shelters, but by the relatively higher risk of establishing an outside- compared
to a within-colony breeding territory. To test whether cichlids prefer within- to outside-colony breeding territories, we
provided breeding shelters inside the colony and at the colony edge and studied helper dispersal. As expected, significantly
more shelters were occupied within the colony compared to the edge. New breeding pairs with several helpers occupied these
shelters. We conclude that although breeding habitat is plentiful outside the colonies, helpers delay dispersal to obtain
a higher quality breeding position within the group or colony eventually, or they disperse in groups. Our results suggest
that (1) group augmentation and Allee effects are generally important for dispersal decisions in cooperatively breeding cichlids,
consistent with the ‘benefits of philopatry hypothesis’, and (2) habitat saturation cannot fully explain delayed dispersal
in these species. 相似文献