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951.
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Latency and development of Botrytis cinerea were assessed under field conditions and after artificial inoculation of two grape varieties, Gamay (susceptible) and Gamaret (resistant). When the percentage of latent Botrytis was the same for both varieties, severity of visible grey mould remained very low in Gamaret berries, while Gamay clusters were destroyed by the disease to a high percentage. Some biochemical parameters were measured in berries, such as constitutive and induced anti‐fungal compounds, polymeric proanthocyanidins and lipid peroxidation products as markers of senescence. Differences were observed in polymeric proanthocyanidins (PPRA) of Gamaret compared with those of Gamay. Concentration and mean degree of polymerization (mDP) of PPRA were always higher in the berries of the resistant variety. The inhibitory effect of Gamaret PPRA on enzyme activity remained until harvest whereas Gamay PPRA lost their inhibitory activity at the beginning of véraison. Based on these results, resistance to B. cinerea seems to be linked to the maintainance of the fungus in its latent form in berries, mainly due to the ability of Gamaret PPRA to inhibit macerating fungal enzyme activities. 相似文献
955.
956.
O Iu Filimonova S A Grudinina S V Sidorenko L K Katosova M A Fatova L G Stoliarova N V Dubrovskaia 《Antibiotiki i khimioterapii͡a》2004,49(12):14-20
The results of 3-year observation on emergence of H. influenzae antibiotic resistant strains in Moscow are summarized. The study included 566 strains isolated from patients in 2002-2004. The susceptibility was determined by the 2-fold microdilution method on the Haemophilus test medium. The percentage of the resistant strains isolated in 2002, 2003 and 2004 was the following: ampicillin --4.9, 3.2 and 3.6%, tetracycline--3.3, 3.2 and 1.8% and co-trimoxazole--10.9, 20.9 and 20% respectively. The strains isolated in 2003 and 2004 were resistant to azithromycin in 0.6 and 1.8% of the isolates and to clarithromycin in 1.3 and 3.2% of the isolates respectively. Five isolates differed by the minimum resistance to ampicillin whereas producing no beta-lactamase (BLNAR strains). The drugs of choice for the treatment of respiratory tract infections mainly due to H. influenzae, i.e. acute otitis and sinusitis, chronic bronchitis exacerbation and sometimes pneumonia remain betalactam antibiotics. From the microbiological viewpoint the inhibitor-protected aminopenicillins, cefuroxime and cefotaxime have no significant advantages vs. amoxycillin. The use of cotrimoxazole and chloramphenicol should be considered inexpedient. 相似文献
957.
958.
The apyrene paraspermatogenesis in the freshwater gastropod
Pomaceacanaliculata has been studied with electron
microscopy. Matureapyrene parasperm result from a cytodifferentiation
processwithout maturation division. The atypical condition is
recognizedearly. Paraspermatogonia are characterized by voluminous
nucleiwith irregular clusters of heterochromatin, numerous dilated
cisternaeof the rough endoplasmic reticulum and small electron-dense
granulesspread through the cytoplasm. As this process advances, the
nucleibecome lobed and chromatin degenerates. The remnant chromatin
condensesto form dense bodies which are finally excreted from the
cells.At the cytoplasmic level a centriolar multiplication with the
consequentflagellogenesis takes place. The axonemal microtubules run
alongthe entire length of the cell and emerge from the posteriorend
forming a tuft of three or more free flagella. The roughendoplasmic
reticulum and the Golgi complex are involved inthe production of
secretory granules, some of which are laterreleased by exocytosis. At
the end of paraspermatogenesis matureapyrene parasperm are
fusiform-shaped anuclear ciliated cells. (Received 20 January 2000; accepted 18 July 2000) 相似文献
959.
960.
Problem of three-dimensional structure of chromatin is reviewed. Data concerning ranged distribution of chromosomes in nucleoplasm are shown. Special attention being paid to the role of nuclear matrix in maintenance of nucleus topology. Possible role of satellite sequences and DNA-binding proteins is discussed. 相似文献