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921.
Fillet samples of the toothfish Dissostichus eleginoides and D. mawsoni can be distinguished readily by muscle proteins revealed by isoelectric focusing and mitochondrial DNA markers. The proteins also distinguish toothfish from other species marketed under similar trade names. 相似文献
922.
923.
924.
Partial purification of the maturation-promoting factor MPF from unfertilized eggs of Xenopus laevis 总被引:5,自引:0,他引:5
P Nguyen-Gia M Bomsel J P Labrousse C L Gallien H Weintraub 《European journal of biochemistry》1986,161(3):771-777
A 200-fold purification of the maturation-promoting factor or MPF from unfertilized eggs of Xenopus laevis is reported for the first time. Purification was achieved by three successive column chromatographies on hydroxyapatite, trisacryl blue and L-arginine-agarose. The presence of MPF was assessed by the usual maturation criteria after injections of test material into immature stage VI unstimulated X. laevis oocytes: the precocious appearance of the maturation spot (within 45-120 min), the germinal vesicle breakdown, the presence of the first polar body and the second metaphase spindle. Purification was monitored by the decrease of the minimal amount of protein injected in a constant volume (50 nl) required to induce 50% frequency of germinal vesicle breakdown. This amount decreased from 500 ng in the crude extract to 2.5 ng in the 200-fold purified material. Analysis by SDS-PAGE of the crude extract showed about 40 Coomassie-blue-stained polypeptides with molecular masses ranging from 300 kDa to 20 kDa, whereas in the 200-fold purified MPF only 5 stained polypeptides were revealed, with molecular masses of 62, 53, 49, 39 and 37 kDa. In vitro phosphorylations for the detection of kinase activities for endogenous and exogenous substrates were monitored by analysis of autoradiograms of SDS-PAGE, after treatment of fractions with [gamma-32P]ATP. Only inactive fractions eluted from columns ahead of MPF, and fractions containing MPF activity were tested. Phosphorylation of numerous stained polypeptides was demonstrated in the crude MPF extract and exogenous substrates such as phosvitin, casein and histone type II-AS were also strongly phosphorylated. In the MPF fraction, purified on hydroxyapatite, a polypeptide of 53 kDa was more highly and specifically phosphorylated and the presence of kinase activities was observed for the above three exogenous substrates. In the 100-fold and 200-fold purified MPF, phosphorylation of endogenous substrates could not be shown and kinase activities for the above three substrates were drastically decreased as compared with the crude and purified MPF obtained after hydroxyapatite column chromatography. However, neither endogenous phosphorylations nor kinase activities with the above exogenous substrates could be shown in inactive fractions eluted ahead of MPF at the different purification steps. Some characteristics of the purified material are also described in this paper. 相似文献
925.
J W Costerton 《Canadian journal of microbiology》1988,34(4):513-521
926.
W J Theuvenet T Nolthenius-Puylaert Z L Giedrojc Juraha J M Borghouts R van Twisk 《Plastic and reconstructive surgery》1984,74(4):539-543
Idiopathic calcinosis of the scrotum is a rare disease that may cause massive deformation of the scrotal wall. The first patient we present was also known to have neurofibromatosis. In the second patient we describe, nodules of idiopathic calcinosis of the scrotum were seen with walls that evidenced no epithelial lining, as well as calcification in epithelial cysts. At present, the only possible treatment is excision, and we excised the afflicted skin without problems in primary wound closure. 相似文献
927.
928.
929.
Cyclic AMP is not detectable in Clostridium perfringens 总被引:3,自引:0,他引:3
Cyclic AMP was not detected (less than 5 X 10(-9) M intracellular concentration) at any stage of growth or sporulation of two strains of Clostridium perfringens grown with or without methylxanthines. Only Bacillus and Lactobacillus, genera belonging to the same phylogenetic cluster, have previously exhibited undetectable levels of cyclic AMP. 相似文献
930.
One hundred and forty-four isolates of dairy origin were identified using a number of commercially available test kits. Agreement between these kits was acceptable for assignment of isolates to genera, but there was some variation between the kits for the identification of the isolates at specific level. The reasons for these variations are discussed. In terms of cost, ease of performance and accuracy, the identification systems manufactured by Roche Products Ltd (viz. the Oxi/Ferm tube and the Enterotube) are considered to be the best suited to the routine identification of dairy micro-organisms. 相似文献