The Experts below are selected from a list of 45 Experts worldwide ranked by ideXlab platform
A S Clarke - One of the best experts on this subject based on the ideXlab platform.
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studies on the life cycle of the pseudophyllidean cestode schistocephalus solidus
Journal of Zoology, 2010Co-Authors: A S ClarkeAbstract:Summary 1A study of host-parasite relationships has been made on the cestode Schistocephalus solidus Muller by examining conditions relating to the infection and growth of the plerocercoid in the stickleback, and- its transfer to other hosts for maturation; the infection of Cyclops by the coracidimn with its subsequent change to a procercoid; and the passage of the procercoid into the body cavity of the fish to become a plerocercoid. It has been possible, by establishing suitable techniques, to carry out the whole life cycle in the laboratory and so facilitate these studies. 2Eggs were obtained from plerocercoids and observations made on their development. The time of hatching of the Coracidium varies considerably, both with temperature and with intrinsic factors. The average time is about three weeks but hatching may occur up to six months after the eggs have been shed. 3From such eggs, free coracidia and, subsequently, procercoids in Cyclops and nauplii, were secured and studied. The growth rate of procercoids was determined together with the effect of infection on the growth of nauplii. 4Infections in fish were secured from infected Cyclops but not in sufficient numbers to justify more than tentative conclusions about the growth rate of plerocercoids. The time required for penetration of the fish gut wall by the procercoid can be as short as two hours. 5Changes in morphology of the worm in its transformation from a Coracidium to a plerocercoid were surveyed and it was shown how the formation of the musculature precedes the initiation of strobilation which occurs rapidly and completely, followed immediately by the formation of the genital rudiments. 6The excretory system of the plerocercoid could be displayed effectively by a method of embedding in transparent plastic. 7Infected fish from one source were collected throughout the year and the weights of the fish and of the worms within them were ascertained. It was found that in the autumn there was an increase in the number of large fish in the marginal zone–possibly related to an increase of plankton–but during the months from winter to summer the mean size of fish was less and remained relatively stable in this zone. The mean weights of plerocercoids however, increased during this period as did the temperature of the water. Some indications of the growth rate of the plerocercoid were observed from the collected data. 8An examination of the stomach contents of the fish showed a wide variety of diet with little or no change throughout the year and also indicated that Cyclops form an almost insignificant feature in this diet.
F Maamouri - One of the best experts on this subject based on the ideXlab platform.
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Observations sur le developpement de
'EDP Sciences', 2014Co-Authors: Azzouz N Draoui, F MaamouriAbstract:Le Bothriocephalidae Clestobothrium crassiceps possède un oeuf operculé et un Coracidium cilié. La diagnose du genre est modifiée en conséquence
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observations sur le developpement de clestobothrium crassiceps rud 1819 cestoda pseudophyllidea parasite intestinal de merluccius merluccius l 1758 teleostei
Parasite, 1997Co-Authors: Azzouz N Draoui, F MaamouriAbstract:Le Bothriocephalidae Clestobothrium crassiceps possede un oeuf opercule et un Coracidium cilie. La diagnose du genre est modifiee en consequence.
Claus Wedekind - One of the best experts on this subject based on the ideXlab platform.
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The infectivity, growth, and virulence of the cestode Schistocephalus solidus in its first intermediate host, the copepod Macrocyclops albidus
Parasitology, 1997Co-Authors: Claus WedekindAbstract:In an experiment to study the infectivity, growth and virulence of Schistocephalus solidus in their first intermediate host, copepods of the species Macrocyclops albidus were kept singly and exposed to up to 9 coracidia. Eleven or 14 days post-infection (p.i.) the presence and growth of the cestode larvae relative to survival, growth and reproduction of their host was determined. As expected, the probability of a copepod becoming infected increased with increasing numbers of parasites administered. However, the chances of a single Coracidium establishing in a copepod also increased with increasing numbers of coracidia administered, which indicates that the parasites profit from a dilution effect of the host's defence. Copepod size or developmental stage had no significant effect on the infection, but 14 days p.i., constraining effects of copepod size on the growth of the parasites were apparent. Moreover, procercoids in multiple infections grew smaller and developed their cercomer at a smaller size than those in single infections. No significant effect of the parasite on host mortality was found within the observation period. However, growth between the 5th copepodid stage and adult stage was negatively affected by infection. An infection with S. solidus was also strongly linked with host reproduction: infected females were more likely to bear an egg sac at the end of the experiment than non-infected ones. These egg sacs, however, contained fewer eggs.
Azzouz N Draoui - One of the best experts on this subject based on the ideXlab platform.
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Observations sur le developpement de
'EDP Sciences', 2014Co-Authors: Azzouz N Draoui, F MaamouriAbstract:Le Bothriocephalidae Clestobothrium crassiceps possède un oeuf operculé et un Coracidium cilié. La diagnose du genre est modifiée en conséquence
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observations sur le developpement de clestobothrium crassiceps rud 1819 cestoda pseudophyllidea parasite intestinal de merluccius merluccius l 1758 teleostei
Parasite, 1997Co-Authors: Azzouz N Draoui, F MaamouriAbstract:Le Bothriocephalidae Clestobothrium crassiceps possede un oeuf opercule et un Coracidium cilie. La diagnose du genre est modifiee en consequence.
Nico Smit - One of the best experts on this subject based on the ideXlab platform.
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Ultrastructure of the uterus, embryonic envelopes and the Coracidium of the enigmatic tapeworm Tetracampos ciliotheca (Cestoda: Bothriocephalidea) from African sharptooth catfish (Clarias gariepinus)
Parasitology Research, 2020Co-Authors: Aneta Yoneva, Roman Kuchta, Nico SmitAbstract:Transmission electron microscopy (TEM) was used to study the ultrastructure of the uterus and egg morphology in the enigmatic bothriocephalidean tapeworm Tetracampos ciliotheca . The uterine wall, underlain by well-developed muscle bundles, consists of a syncytial epithelium which is characterized by the abundance of free ribosomes, mitochondria and cisternae of granular endoplasmic reticulum (GER). On the apical surface of the uterine epithelium, there is an abundant network of cytoplasmic microlamellae projecting into the uterine lumen. The lumen is filled with freely lying eggs which are located close to the uterine wall but do not contact with the microlamellae of the uterine epithelium. The developed eggs possess an oncosphere surrounded by four envelopes: (1) a thin egg shell; (2) an outer envelope; (3) a syncytial, ciliated inner envelope; and (4) the oncospheral membrane. The mature hexacanth is armed with three pairs of oncospheral hooks, as well as somatic and hook muscles and five types of cells (1) binucleated subtegumental cell, (2) somatic cells, (3) penetration gland cells, (4) nerve cells and (5) germinative cells. Considering the relative scarcity of descriptive and comparative studies on the ultrastructure of the uterus and egg morphology in the order Bothriocephalidea, we concluded that Tet. ciliotheca displays a unique type of egg development. Based on these results, we discuss plausible ideas relating to the function of these structures for consideration in future studies.