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Cope's rule concerns only the radiation phase of a clade, overlooking the phase of the clade decline; thus it is incomplete. Changes of body size during the entire evolutionary history of a clade are exemplified here by three trilobite groups - Ptychopariina, Asaphina and Phacopida. Increasing diversity of the clade is associated with increase in maximum body size during the radiation phase, and decreasing diversity is generally associated with a decrease in maximum body size. Two basic patterns of the maximum body size changes are observed during the decline of the clade. The first one is characterized by a high correlation between diversity and the maximum body size, and indicative of species attrition that is nonselective with respect to the body size. The second one is characterized by a weak correlation between diversity and maximum body size, and typical of selective species attrition in relation to size.
The aim of the study was to make an attempt at showing the intraspecies heterogenecity of Malassezia pachydermatis strains with regards to their origin (strains isolated from healthy dogs and with otitis externa symptoms). The study included 41 strains of Malassezia pachydermatis species isolated in a pure culture from dogs with clinical otitis externa symptoms (n = 20), clinically healthy dogs (n = 20) and a reference strain, M. pachydermatis (CBS7925). In order to isolate the genetic material from the fungal cells, the following four procedures were selected: mechanical, enzymatic, thermal and chemical. Considering the yield and repeatability of a method for the genomic DNA extraction, a mechanical method was applied. The genetic material research of each strain was performed according to PCR-REA technique with the amplification of three genome regions: ITS, LSU rRNA and a gene encoding beta-tubuline. The ITS and LSU rRNA regions were amplified employing the standard PCR reagents, whereas the region coding beta-tubuline with the so called touch down. The obtained amplification products were subjected to restrictive analysis by means of the following enzymes: EcoRI, Ncol, Hinfl, Alul, and Eco881 (Aval). The performed investigations made it possible to reveal the genotypic differentiation within M.pachydermatis species as well as some correlation between a genotypic profile and the origin of a strain (from healthy animals or with otitis externa symptoms), which may imply the existence of genetic conditioning of the Malassezia strains’ pathogenicity.
A new species of the taeniolabidid multituberculate Catopsalis is described from the Simpson Quarry fauna of the Puercan age Bear Formation of the Crazy Mountains Basin, south-central Montana. The molars retain a conservative cusp formula, yet are distinct from those of other early members of the genus in their extremely large size, which is approximately the same as that of C. calgariensis from the late Torrejonian to early Tiffanian. The combination of apomorphic and plesiomorphic features in the new species indicates a greater degree of complexity in the evolution of the genus than previously recognized.
Technikę AFLP (Amplified Fragment Length Polymorphism) zastosowano do identyfikacji gatunku і do oceny wewnątrzgatunkowej zmienności szczepów B. pertussis, В. parapertussis oraz В. bronchiseptica. Wykazano przydatność metody AFLP do określania gatunkowej przynależności szczepów B. pertussis, В. parapertussis і В. bronchiseptica oraz wewnątrzgatunkowego różnicowania szczepów B. pertussis i B. bronchiseptica.
Badaniami objęto 34 szczepy P. putida, z których 27 izolowano z gleby zanieczyszczonej pochodnymi ropy naftowej, 3 z biopreparatów stosowanych w procesach biodegradacji zanieczyszczeń oraz 4 z ran i owrzodzeń. Podjęto próbę wewnątrzgatunkowego różnicowania szczepów P. putida wykorzystując ich aktywność biochemiczną, wzory lekowrażliwości i określając zymotypy. Stwierdzono przydatność tych metod w diagnostyce mikrobiologicznej pałeczek P. putida.
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Exceptionally well-preserved shells of the endocerids Dideroceras wahlenbergi (Foord, 1887), Anthoceras vaginatum (Schlotheim, 1820), and Suecoceras barrandei (Dewitz, 1880) from phosphatized Early and Middle Ordovician limestones of Northern Estonia were studied by means of SEM. The septal neck in these endocerids is composed of three, structurally different, aragonite layers: outer spherulitic-prismatic, nacreous, and inner prismatic. The connecting ring is a continuation of the spherulitic-prismatic layer of the septal neck. Its inner surface was probably covered by a thin glycoprotein (conchiolin) sheet. Structural differentiations in the spherulitic-prismatic layer of the connecting ring, such as a layering and 'eyelet', reported by previous writers, were not observed. These differentiations probably result from diagenesis. The siphuncular structure in endocerids agrees in detail with that in Recent Spirula and Nautilus. The conical endosiphuncular deposits (endocones) of endocerids show extensive intraspecific variation. Morphological and structural differences in these deposits should therefore be used with caution in generic and specific diagnoses.
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