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861.
Six diel TCO2 cycles determined by infrared (IR) photometry from five drift stations occupied between 24 February and 16 March 1979 in the mixed layer of the northwestern Caribbean Sea are examined. Comparison of TCO2 variation with coincident salinity and O2 variation demonstrated that TCO2 often co-varied with these independently measured variables. During five diel cycles TCO2 variation was characterized by nocturnal production and diurnal consumption. The inverse, diurnal production of CO2, occurred downstream from Misteriosa Bank, whose corals apparently contributed to a water mass having a twofold increase of POC and a sixfold larger population of heterotrophic nanoplankters. For the five diel studies carried out in waters with balanced or nearly blanced heterotrophic and phototrophic components of the nanoplankton, CO2 consumption at constant salinity always occurred between 06.00 and 09.00 hrs. Net uptake often continued through 15.00 hrs, but not always in the absence of significant salinity changes. At constant salinity net O2 evolution never exceeded 0.5 mol l-1 h-1 while net CO2 uptake consistently averaged 3 mol l-1 h-1 for an apparent net production of 36 mg C m-3 h-1, which greatly exceeds the O2 changes and open ocean 14C estimates from the literature. Diurnal consumption was apparently balanced by nocturnal production of CO2 so that no significant net daily change in TCO2 was observed. Departures from theoretical PQ and RQ and the possibility of nocturnal variations in formaldehyde and carbonate alkalinity imply that chemotrophs, both methane producers and methane oxidizers, play a significant role in CO2 cycling. This could be through the metabolism of the nonconservative gases CH4, CO, and H2, and a link between chemotrophy and phototrophy through these gases is hypothesized. These open system measurements were subject to diffusion and documentable patchiness, but temporal TCO2 changes appear to indicate the net direction of microbiological activity and join a growing body of literature showing dynamic variation in CO2 and O2 that exceeds estimates by 14C bottle assays of carbon fixation. 相似文献
862.
863.
864.
865.
The soluble fraction (105,000 x g, 30 min) of chicken liver homogenates contained an enzyme(s), probably a dehydrochlorinase(s), which metabolized lindane in vitro. The reaction was glutathione dependent and took place anaerobically. The enzyme(s) also metabolized the alpha- and delta-isomers but not the beta-isomer. About 66% of the in vitro metabolites were soluble in petroleum ether. From the ether-soluble fraction, o-, p- amd m-dichlorobenzene, 1,2,3- and 1,2,4-trichlorobenzene, gamma-2,3,4,5,6-pentachlorocyclohex-1-ene (gamma-PCCH), 2,3- and 2,4-dichlorophenol and 2,4,6-trichlorophenol were identified by comparison of mass spectra and gas chromatographic data with those of reference compounds. Seven additional metabolites were tentatively identified from their mass spectra data. These metabolites were: chlorobenzene, 2 isomers of trichlorocyclohexene, dichlorocyclohexadienetriol, chlorophenol, trichlorocyclohexenol and trichlorocyclohexanediol. The petroleum ether-extracted aqueous phase contained a number of unidentified conjugated metabolites. It was concluded that the metabolic pathway for lindane in the chicken is quite similar to that in the pheasant. 相似文献
866.
867.
We have adapted a procedure which was developed for studying the correlations in the distribution of genetic factors, such as sex ratios in siblings, to obtain estimates of the correlation between the number of mutagens and the number of nonmutagens in a sample. Positive correlations with correlation coefficients in excess of 0.8 were obtained. The high correlation suggests that it is possible to estimate the number of mutagens in samples with N > 100 compounds as (0.064 ± 0.01) N. 相似文献
868.
Gallstones are precipitations of oversaturated bile fluid. They can develop in the gallbladder and in the efferent bile ducts; they are very often correlated with diseases of the gallbladder, bile ducts and neighboring organs. The gallstone disease (cholelithiasis) is increasing continually, especially in developed countries with overcaloric nourished population. Surgical interventions on the biliary tract are the most frequent abdominal operations at present. 相似文献
869.
870.
Sediments of various newly discovered deeps in the Red Sea were analyzed for the occurrence of denitrifying bacteria. The samples were collected in 1972 during the Valdivia cruises. Among the 27 different samples investigated, 17 revealed both coccoid and rod-shaped bacteria when enriched in complex nutrient broth (with 10% NaCl). Denitrifiers were recorded abundantly in the sediments, their population decreasing from some 106/g in the surface material to only a few in the subsediment. A total of 16 pure cultures of denitrifying bacteria were isolated from the Suakin-and Thetis-deeps and studied morphologically, physiologically and biochemically. Genetics (molar percentage of guanine plus cytosine, % GC) and numerical taxonomy were included to reveal relationships and improve taxonomic classification. Fifteen isolates were described as Gram-negative, aerobic and facultative anaerobic (with NO
3
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as H+-acceptor), polarly flagellated rods (Pseudomonas spp.); one was an inmotile, Gram-positive, facultative anaerobic coccus. None of the 15 Pseudomonas-isolates could be identified with one of the denitrifying species so far described and recognized. The strains should be regarded as hitherto undescribed denitrifying marine bacteria.Supported by the Bundesministerium für Forschung und Technologie, Bonn, Germany (FRG). 相似文献