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21.
Macrobenthic fauna and sediment structure were studied at 6 stations from June 1979 to April 1981. The investigations were carried out in the outer estuary of the River Elbe at depths of 15–38 m near a sewage sludge dumping site. The sediment near this area consisted of a high portion of silt. Usually, very few species and small numbers of individuals were found near that dumping ground. During summer 1980, a mass development ofAbra alba and several polychaete species caused an increase in species number which broke down during the following winter. The mass development observed in the study area was apparently not directly caused by the sludge dumping itself, but reflects the natural variability of the community structure. The number of species recorded was significantly correlated with a grain size fraction>31 μm, especially in summer. The seasonal and spatial fluctuation of the benthic community could be well documented by the abundance per species (N/S index). The Shannon-Wiener-Index (H′) and eveness (J) were also useful indicators of community variability. The log-normal distribution did not show the seasonal and the spatial differences of the stations. Possible reasons are discussed. The biomass at the stations near the dumping area was less except during the mass development ofA. alba. The average individual weight (B/N) was shown to be a good indicator of population fluctuations; polychaete biomass was positively correlated to a grain size fraction≦6 μm, that of molluscs to a grain size fraction>31 μm.   相似文献   
22.
Formation of gas and of methylated sulfur compounds was observed in anaerobic enrichment cultures with methoxylated aromatic compounds as substrates. Via direct dilution of mud samples in defined reduced media supplemented with trimethoxybenzoate or syringate two new strains of anaerobic homoacetogenic bacteria (strain TMBS4 and strain SA2) were obtained in pure culture. Both strains produced dimethylsulfide and methanethiol during growth on methoxylated aromatic compounds. Growth tests and determination of stoichiometries demonstrated that the volatile sulfur compounds were formed from the methyl group at the aromatic ring and the sulfide added as reducing agent to the medium (R = aromatic residue): 2 R - O - CH3 + H2 S 2 R - OH + (CH3)2SDimethylsulfide was the major organic sulfur compound formed, whereas methanethiol appeared only as intermediate in small quantities. The isolates grew also with trihydroxybenzenes such as gallate, phloroglucinol, or pyrogallol without formation of methylated sulfur compounds. The aromatic compounds were degraded to acetate. The freshwater strain TMBS4 also fermented pyruvate. Other aliphatic or aromatic compounds were not utilized. External electron acceptors (sulfate, nitrate, fumarate) were not reduced. Both strains were mesophilic and formed rod-shaped, non-motile, Gram-negative cells. Spore formation was not observed. Tentatively, both isolates can be affiliated to the genus Pelobacter.Abbreviations TMB 3,4,5-trimethoxybenzoate - MT methanethiol - DMS dimethylsulfide  相似文献   
23.
Summary A total of 56 Duchenne muscular dystrophy (DMD) patients and 11 Becker muscular dystrophy (BMD) patients was analyzed by extended multiplex amplification of the DMD/BMD gene; deletions were found in 60% of these patients. The data obtained were used to test the frameshift hypothesis and to compare the distribution of familial versus isolated cases. A significant correlation was found between deletions and isolated cases. Additional experiments were performed in order to determine the deletion breakpoints more precisely. These data are a prerequisite for carrier analysis in the respective families by detection or exclusion of aberrant cDNA fragments derived from ectopic lymphocyte RNA. This diagnostic technique is illustrated by 5 examples.  相似文献   
24.
The p53 gene has been associated with malignant transformation as well as "anti-oncogene" activity. In the present report expression of p53 in resting and activated human blood monocytes and lymphocytes is analyzed. It is found that human monocytes freshly isolated by continuous percoll gradient centrifugation contained detectable level of p53 mRNA. Stimulation of monocytes by potent activation inducer Staphylococcus Aureus Cowan I for 3-5 hr caused disappearance of r53 mRNA. In contrast, induction of high level of TNF-alpha mRNA was detected. Addition of cycloheximide had no effect on p53 mRNA content in stimulated monocytes, and caused disappearance of mRNA in resting cells. In lymphocytes cultures p53 mRNA was absent in freshly isolated cells and in resting lymphocytes cultured for 20 hr. Activation of lymphocytes by lectin caused accumulation of p53 mRNA. We suggest that r53 gene regulation and functions might be different in human monocytes and lymphocytes.  相似文献   
25.
26.
A single X-ray irradiation of the rabbit hindlimbs in a dose of 0.24 C/kg evokes a decrease in fluorescence of the ANS probe bound with membranes of the sarcoplasmatic reticulum as a result of the decrease of binding sites, binding constant as well as the quantum output of the probe. A decrease in fluorescence of tryptophan residues of Ca-ATPase localized in membranes and attenuation of interaction of its SH-group with dithionitrobenzoic acid has been also observed at early postradiation terms (1 and 24 h). The obtained results evidence for structural rearrangements occurring in membranes of the sarcoplasmic reticulum under the effect of ionizing radiation. Changes in conformation of CA-ATPase molecules contribute much to this process.  相似文献   
27.
When a new strain of Pseudomonas aeruginosa was grown aerobically and then transferred to anaerobic conditions, cells reduced NO 3 quantitatively to NO 2 in NO 3 -respiration. In the absence of nitrate, NO 2 was immediately reduced to NO or N2O but not to N2 indicating that NO 2 -reductase but not N2O-reductase was active. The formation of the products NO or N2O depended on the pH in the medium and the concentration of NO 2 present. When P. aeruginosa was grown anaerobically for at least three davs N2O-reductase was also active. Such cells reduced NO to N2 via N2O. The new strain generated a H+-gradient and grew by reducing N2O to N2 but not by converting NO to N2O. For comparison, Azospirillum brasilense Sp7 showed the same pattern of NO-reduction. In contrast, Paracoccus denitrificans formed 3.5 H+/NO during the reduction of NO to N2O in oxidant pulse experiments but could not grow in the presence of NO. Thus the NO-reduction pattern in P. denitrificans on one side and P. aeruginosa and A. brasilense on the other was very different. The mechanistic implications of such differences are discussed.  相似文献   
28.
Verrucaria schaereri (Fr.)Nyl. is accorded generic status asPlacocarpus Trev. emend.O. Breuss. The main differences between the two genera concern the thallus anatomy and the spores which are halonate inPlacocarpus. The following new combinations are proposed:Placocarpus schaereri (Fr.)O. Breuss andPlacidiopsis cinerascens (Nyl.)O. Breuss.  相似文献   
29.
From differentiated plants of Catharanthus roseus (L.) G. Don we have isolated a specific enzyme of the vindoline biosynthetic pathway catalysing the S-adenosylmethionine-dependent methylation of 11-O-demethyl-17-O-deacetyl-vindoline. The enzyme we named S-adenosyl-L-methionine : 11-O-demethyl-17-O-deacetylvindoline 11-O-methyltransferase. This transferase exhibits a high substrate specificity. Obviously the O-methylation at C-11 precedes the O-acetylation at the C-17 position during the biosynthesis of vindoline.A second enzyme was detected which hydrolyses the acetyl function of vindoline. The distribution of this acetylesterase in C. roseus plants demonstrates that the enzyme is not specifically associated with the vindoline distribution in the plant material. Most probably this enzyme plays no essential role in the biosynthesis of vindoline.  相似文献   
30.
V P Vo?tenko 《Genetika》1984,20(3):512-518
The correlation analysis of ratios between six polymorphic genetic systems (ABO, MNSs, Rh, Hp, Gm, HLA) and mortality from ishemic heart disease, brain vascular lesions, and hypertensive disease in 17 European populations has been made. A statistically significant correlation has been established between the populational frequency of most of the 50 phenotypes and genes under study, and mortality. The qualitative structure of correlations and their quantitative expression depend on the cause of death, age and sex. The possible mechanisms of relationship between the genetic populational differences and mortality from cardiovascular diseases are discussed.  相似文献   
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