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A.C. Gonçalves T.D. Matos H.R. Simões-Teixeira M. Pimenta Machado M. Simão Ó.P. Dias M. Andrea G. Fialho H. Caria 《Gene》2014
Low-frequency sensorineural hearing loss (LFSNHL) is an unusual type of HL in which frequencies at 2000 Hz and below are predominantly affected. Most of the families with LFSNHL carry missense mutations in WFS1 gene, coding for wolframin. 相似文献
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Synchronously growing cells of nitrogen-fixing Synechococcus sp. Miami BG 043511 were harvested periodically and the capability for hydrogen photoproduction in closed vessels was measured under hydrogen production conditions. The capability for hydrogen photoproduction in cells was correlated with that of cellular carbohydrate content. Cells with a high carbohydrate content exhibited a high capacity for hydrogen production and those with low carbohydrate content exhibited low capacity for hydrogen production. Nitrogenase activity at the onset of incubation did not coincide with a capability for the cells to produce hydrogen during the subsequent incubation period. Interestingly, when cells with a high capacity for hydrogen photoaccumulation were incubated, alternate periods of hydrogen and oxygen accumulation were observed at 12 hour intervals. About 0.5 ml of hydrogen per ml of cell suspension was accumulated in flasks during the initial 12-h incubation period. These observations indicate that the use of synchronous culture can be one of the ways of provide materials suitable not only for basic studies but also for applied aspects of hydrogen photoproduction. 相似文献
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Abstract Little information exists about nitrogen losses through microbial activity during treatment of solid urban waste (SUW) by processes such as composting. In the present study, in addition to evaluating the pattern of nitrogen losses by denitrification at different stages of the process, a comparison between the method of Pochon and Tardieux, and an improved gas chromatographic method for estimating denitrifying populations was undertaken, Though the MPN (Most Probable Number) enumerations were higher using the colorimetric method than the gas chromatographic one, the patterns of the two graphs showing numbers of denitrifiers during composing were the same. The highest numbers were revealed immediately after loading the reactor (107 –108 /g d.w.), lower numbers of denitrifiers were found in the second sampling corresponding to the thermophilic phase (103 –104 /g d.w.). These numbers increased gradually as the waste material stabilized (10th to 123rd day of composting) to again reach values of 107 –108 /g d.w. 相似文献
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A.C. Cockcroft H.H. Du Preez 《Journal of experimental marine biology and ecology》1990,140(3):159-171
Nitrogen excretion and assimilation efficiencies in Lithognathus mormyrus (Linnaeus), a marine teleost present in high-energy surf zones in Algoa Bay, South Africa, were determined under controlled laboratory conditions at 15, 20 and 25 °C. Ammonia was the major form of nonfaecal nitrogen excreted by starved and fed L. mormyrus. Urea and amino acids were secondary excretory products. Ammonia excretion rates were temperature independent and the excretion rates of fed fish were significantly higher than starved fish at 20 and 25 °C but not at 15 °C. The mass component (b) of the mass/ammonia excretion equation was temperature independent and ranged from 0.590 to 0.669 and from 0.670 to 0.767 for starved and fed fish, respectively. The mean percentage of food energy lost via the dissolved nonfaecal excretory products (exogenous plus endogenous) was 4.12%. Assimilation efficiencies ranged from 71.89 to 98.78% for dry matter and from 96.89 to 99.88% on an energy basis. The combined nonfaecal and faecal energy loss was calculated at 10.11% of the ingested energy. The omnivorous ichthyofauna present in the surf zone ecosystem recycle 33 g N · m strip · yr−1. This constitutes < 1 % of total phytoplankton nitrogen requirements. 相似文献
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Six to seven week old red clover plants (Trifolium pratense L. cv Merviot) were used to investigate the time-course of root senescence following complete and permanent excision from
the shoot. Plants were grown in sand culture watered with nutrient solution. After excision of the shoots, roots were left
in situ and sampled over a period of up to 42 days. Respiration rate began to decrease immediately after excision, reaching
50% of its initial value after 24 h. The decline involved a reduction in the capacity of the respiratory pathways as measured
in the presence of an uncoupler (FCCP) and exogenous glucose. The reduction in respiration could be prevented by supplying
100 mM sucrose to excised roots incubated in nutrient solution at the time of excision, but not 4–5 days after excision. There
was a steady reduction in the protein and soluble sugar concentrations from the time of excision and a smaller reduction in
starch. Free amino acid concentrations increased immediately after excision, but the temporal dynamics differed between individual
amino acids. The total concentration of free amino acids rose to a maximum value 6–13 days after excision, before declining.
Under these conditions roots survived for a remarkably long period of time. Depending on the experiment, cell viability, measured
as the percentage of cells with positive turgor, was unchanged for at least 20 days, and complete loss of viability was not
observed until 34–42 days after excision. There was no appreciable loss of N from the roots until cell viability declined
significantly. The potential implications of these results for modelling and management of N cycling in cropping systems is
discussed briefly. 相似文献
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