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31.
We have used a cloned chicken collagen cDNA sequence to help identify hypothetic members of the collagen gene family from Drosophila melanogaster. Several experimental evidences have been obtained which indicate that the Drosophila genome contains numerous collagen-like sequences. We have characterized in more detail ten distinct DNA sequences that hybridized strongly to the heterologous collagen probe. By in situ hybridization we have shown that these sequences are dispersed throughout the Drosophila genome. Two of them are shown to originate from the previously described DCg 1 and DCg 2 collagen genes. In other respects, we show that in addition to DCg 1 and DCg 2, at least five putative collagen genes are expressed during the Drosophila lifetime. These genes are unique, and some of them are seen to be transcribed into different size classes of mRNAs. Additionally, the data presented so far demonstrate that the expression of these genes is regulated temporally and/or quantitatively during the Drosophila life cycle.  相似文献   
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In the Staphylococcus aureus strain harbouring the plasmid RPAL, the resistance to aminoglycoside antibiotics results from two inactivating reactions catalyzed by a 6'-N-aminoglycoside acetyltransferase and a 2"-O-amino-glycoside phosphotransferase. These enzymes are copurified with a constant ratio between the two activities, the purification process consisting in affinity chromatography, native electrophoresis and gel exclusion chromatography. The kinetic mechanisms of each activity have been determined from studies of initial velocities, as well as product and dead-end inhibitions. Both activities follow a random rapid equilibrium mechanism. The substrates and cofactors of one reaction have been tested as effectors of the other reaction. No interaction between the two activities has been observed. However, the GTP cofactor of phosphotransferase protects, at weak concentrations, the acetyltransferase against thermal inactivation, which suggests that the two activities may be associated.  相似文献   
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Pea enation mosaic virus (PEMV) was isolated from disea sed field pea (Pisum sativum L.ssp. arvense A.Gr.) and broad bean (Faba vulgaris Moench) plants grown as filed crops at Bohumilice in Bohemia. The virus proved to be pathogenic for the following plant species:Pisum sativum L. cv. Raman,Faba vulgaris Moench,Lens culinaris Med.,Vicia sativa L.,Lathyrus odoratus L.,Glycine soja L.,Phaseolus vulgaris L.,Chenopodium amaranticolor Coste andReyn,Nicotiana clevelandi Gray,Trifolium incarnatum L. The dilution end point of the isolate was higher in pea plants (10?4) than in broad bean plants (10?2). The thermal inactivation point was 65–68° and the longevityin vitro between 10 and 14 days. According to the host range, symptoms on pea plants and physical properties the virus isolate studied resembles some isolates described in the U.S.A. and represents a PEMV strain different from those reported so far in Czechoslovakia.  相似文献   
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A new macroscopic screening test for syphilis, the Latex-sts test, is extraordinarily simple. After inactivation of the patient''s serum for 30 minutes at 56°C the test is performed by mixing the patient''s serum with latex particles coated with cardiolipin and a protein fraction obtained from the non-pathogenic Reiter strain of Treponema pallidum. Two to three minutes after mixing, the result of the test is observed on a ringed serologic plate. The sensitivity, specificity and reproducibility of the new test are equivalent to those of the qualitative Venereal Disease Research Laboratory tube test. The advantages of the Latex-sts are that it can be done in a short time, it is simple and it requires a minimum of laboratory equipment. The coated latex particles are stable for 12 months.  相似文献   
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This communication reports the isolation and the purification of the gastric somatostatin receptor from the human cell line HGT-1. The receptor has been extracted from the cell membrane by Triton X 100, and a monoclonal antibody to this was prepared. A series of affinity chromatographies (Sepharose-antibody and Sepharose-somatostatin-14) and a final purification by steric exclusion on high performance liquid chromatography columns (HPLC) allowed us to obtain a fraction enriched 20,000 fold in 125I-Tyrll-somatostatin-14 specific binding (apparent dissociation constant: 7.6 x 10(-8) M). This fraction corresponded to a molecular mass of about 90 kDa (in presence of detergent) and to a maximal binding capacity of more than 10,000 pmol/protein. It therefore has a theoretical homogeneity close to 100%.  相似文献   
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Three cases of leiomyosarcoma are presented. The primary lesion to the stomach was seen in 2 patients while the small intestine in the remaining patient. Two patients underwent radical surgery. All patients were treated with multiple drug regimens. Radiotherapy was additionally carried out in one patient. One patient who underwent radical surgery and given maintaining chemotherapy is alive in the complete remission since 6 years while two remaining patients died within 3 and 6 years because of recurrence and haematopoietic proliferation.  相似文献   
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Book reviews

Improving vegetatively propagated cropsA.J. Abbott and R.K. Atkin (Eds.), London: Academic Press, 1987. xvii + 416 pages. £37.00. 0-12-041410-4  相似文献   
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