Studies of an acrosomal defect in spermatozoa from a platinum fox

An acrosomal defect in the spermatozoa from a platinum fox was studied under light- and electron microscopy. The defect, occurring in about 40 % of the sperm cells appeared under phase-contrast and bright-field microscopy as a knob-like irregularity, mostly rounded or slightly triangular in outline and situated in the apical part of the sperm head. Electron microscopy of the sperm head revealed a marked deviation from the normal development of the acrosome. In most of the cases this structure contained a large membrane bounded vacuole filled with numerous small vesicles and some membranous material. In spermatids studied in the cap-phase, the developing acrosome exhibited a high degree of abnormal morphology, indicating that the development of the defect must have started rather early during the formation of the acrosome.

Some effects of population density in infections of Diphyllobothrium dendriticum (Nitzsch) in golden hamster (Mesocricetus auratus Waterhouse) and common gull (Larus canus L.)

Golden hamsters were given plerocercoids of Diphyllobothrium dendriticum either singly or in groups of 2, 4, 8 or 15. There was a higher rate of recovery of worms from hamsters given many (8 and 15) than from those given few (1, 2 or 4) plerocercoids. The difference in rate of recovery of worms was present from 2 h after administration of plerocercoids and persisted up to day 20 when experiments were ended. Denser tapeworm populations had the smallest individuals and some of them contained worms with primary strobilae at the start of egg production. The size of the tapeworm population did not influence the prepatent time. Also, with the common gull there was a higher rate of recovery of worms when plerocercoids were given in groups. These results are discussed in relation to aspects of the life-cycle of D. dendriticum where the natural final host is most probably normally infected by a larger number of plerocercoids at the same time.

Ultrastructural studies of blue fox spermatozoa

The fine structure of epididymal and ejaculated spermatozoa from blue fox is analyzed by electron microscopy. The result of this investigation seems to indicate that the blue fox spermatozoon is of the same type as that of the dog. The apical body appears, however, to have a rather characteristic shape and to be more well-developed than found in sperm cells from the usual domestic animals.

The other structures studied in the different parts of the blue fox spermatozoon including the head, neck and flagellum displayed the same principal characteristics as those in the sperm cells of other domestic species.

In a few cases double development of the middle piece could be observed.

Morphological and ultrastructural studies of moose spermatozoa

Epididymal spermatozoa from moose were studied in phase contrast, light interference and electron microscope. Some samples taken from cauda were diluted and frozen in liquid N₂. The motility of the sperms after thawing was good.

The concentration of spermatozoa in cauda was calculated to 10 × 10⁶ cells per µl.

Morphologically the spermatozoa of moose were found to be quite similar to those collected from bulls. The length of the sperm head was found to be approx. 8.8 µ and the average maximal width 5.2 µ. The average length of the tail was 54.7 µ and the entire length of the spermatozoon varied from 60 to 64 µ. Compared with sperm cells from bulls the moose spermatozoa appeared to have a somewhat shorter and broader head and a slightly shorter tail.

The migration of the cytoplasmatic droplets, which was found to be completed in caput, seemed to follow the same pattern as in bulls and boars. As found in these species there was also in the moose a higher frequency of secondary abnormalities in the spermatozoa from cauda than in those from the other parts of epididymis.

Studies of the fine structure of the moose spermatozoa seemed to indicate that these are of the same type as the spermatozoa of bulls, rams and boars. In sagittal sections the sperm head was thin, but in contrast to the sperm cells of the species mentioned above no typical waist-like narrowing in the equatorial region was found. The equatorial segment also seemed to be less arched than in the spermatozoa from bulls, rams and boars. Otherwise, no principal difference was found between ultrastructure of the moose spermatozoa and that of the spermatozoa collected from domestic species.