Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 8

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  phenotypic change
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The presently reported study investigated seasonal fluctuations in the prevalence in four species of Nerocila infesting commercially exploited marine fishes representing the families Engraulidae, Clupeidae and Ambassidae, from the Malabar coast (Kerala, India). Seven of 56 fish species belonging to 23 families were infested by either one or two species of Nerocila. All the collected Nerocila species showed significant seasonal fluctuations in the prevalence of infestation, reaching maximum from October through April and minimum (or total absence of the parasites) from May through September. Such fluctuations were analyzed based on environmental parameters. Body surface, postero-ventral side of the head and the lateral line of the host fish form the major infestation site for the recovered Nerocila species. Skin lesion and hemorrhages were observed on the fish parasitized with these cymothoids.
The formation of phenotypic structure of P. infestans population in Poland was determined by analyzing 1603 isolates collected from 1987 to 2001. The race complexity, low at the beginning of experiment, has been increasing from year to year and reached in 2001 a high level 7.2 virulence factors per isolate. The single and less composed races dominating first1y in the population were replaced gradually by more composed races. The virulence factors 1, 2, 3, 4, 7 and 11 occurred most frequent1y, but factors 5 and 8 were noted sporadically. The A2 mating type was detected in 1988 at first and since that time its occurrence has been noted in Polish population each year. The oospores were formed in potato tissues. Race diversity, low at the beginning of the investigation, reached a peak in 1996-2001. During 1987-1990 weakly and middly aggressive phenotypes dominated in Polish population. In the later period very aggressive isolates were more frequent. Phenotypic race similarity of P. infestans populations in 1987 and 2001 was very low. The race structure of 1987 population was totally different from the race structure of populations of the next years. it was probably due to migration of new pathotypes. On the other hand the variation in complexity, diversity and similarity of races, as well as in aggressiveness observed in later years of investigation can be caused by the presence of both mating types and sexual recombination.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.