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The susceptibility of crystalline and amorphous proteins from beans to enzymatic hydrolysis were compared. The crystalline proteins were obtained by precipitating the crystals (5°C, 18 h) from acid extracts. The amorphous forms were obtained by isoelectric precipitation of proteins from alkaline extracts. The content of proteins in crystalline forms was higher (81-82%) than in amorphous forms (77%). The differences were observed for the susceptibilities of crystalline and amorphous proteins to enzymes. The crystalline proteins showed higher values for in vitro digestibility (80-81%) than amorphous proteins (78-80%). The reverse relationship was observed when the proteins were digested with one enzyme, i.e. trypsin, and the results were monitored by electrophoretical separation of proteins and by determining the increase in free a-amino groups.
Electrophoretic methods can be used to identify meat of various animal species. The protein electrophoresis, especially the IEF of the sarcoplasmic proteins, is a wellestablished technique for species identification of raw fish and is used in the control of seafood authenticity. However, in the case of the analysis of heat-processed fish, the method is applicable only to those species which possess characteristic patterns of the heat-stable parvalbumins. Heat-denatured fish muscle proteins may be solubilised by urea or sodium dodecylsulfate (SDS) and separated by urea-IEF or SDS-PAGE, respectively. The comparison of these two methods allowed to conclude that, basically, each of them can be used for species identification of heated fishery products. However, extensively washed products may be preferentially analysed by the SDS-PAGE, because most of the parvalbumins are washed out leaving mainly myosins. On the other hand, the IEF method may be preferred for the differentiation of closely related species rich in parvalbumins isoforms. It is evident from the literature data that species-specific protein separations yield proteins of low molecular weight made up of three light chains of myosin (14-23 kDa), troponin (19-30 kDa) and parvalbumin (about 12 kDa). Investigations showed that the SDS-PAGE method can be used to identify meats of: cattle, sheep, lambs, goats, red deer and rabbits. The technique allowed researchers to identify the following myofibrillar and sarcoplasmic muscle proteins: myosin and actin, -actinin, tropomyosin, troponin. SDS-PAGE allowed the identification of myofibrillar proteins taking into account their molecular weights which was not possible with the assistance of the PAGIF because too many protein bands were obtained. It was possible to obtain differences in the separation of proteins characteristic for certain species, e.g. beef, resulting from the presence of single myofibrillar proteins
In order to provide suggestions for conservation and management of the wolf Canis lupus Linnaeus, 1758 in Italy, a total of 46 wolves from central Italy and 53 mongrel dogs were surveyed for electrophoretic variation within and among populations. Six out of 41 presumptive gene loci exhibited polymorphism in the wolf (P = proportion of polymorphic loci = 0.146, 99 per cent criterion), whilst only 3 loci were variable in the dog (P = 0.073). Expected average heterozygosity in the Italian wolf (mean He= 0.037) was comparable to values reported previously for protein variation in natural wolf populations. By contrast, the dog showed a comparatively low heterozygosity (mean He = 0.020), which may be a consequence of domestication. Nei's (1978) absolute genetic distance between wolf and dog (D = 0.012) was very similar to values reported in previous investigations, thus confirming that they are closely related forms. Relative genetic differentiation (Wright's Fst = 0.167) between wolf and dog was considerably higher than the mean genetic diversity found among several dog breeds. The Jesuits of the present genetic investigation on the wolf population from central Italy suggested that its genetic resources are quite intact. The extent of differences in allelic fre­quencies at loci polymorphic both in wolf and dog did not suggest substantial wolf-dog interbreeding, which has been thought to be one of the major threats to the genetic integrity of the Italian wolf population.
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