Sexual and aggessive behaviour of castrated male sheep after injection of gonadal steroids and implantation of androgens in the hypothalamus: A preliminary study.

The combined effects of hypothalamic steroid implants and subcutaneous hormone injections on the courtship, copulatory and aggressive behaviour of five castrated male sheep (wethers) were assessed in thrice weekly tests with sexually receptive ewes. The animals were prepared with bilateral guide tubes for the insertion of removable hormone-containing cannulae aimed at the preoptic/anterior hypothalamic region of the brain. The sheep were treated as follows: weeks 1-4, cholesterol implants + oestradiol dipropionate injections; weeks 5-7, dihydrotestosterone propionate implants + oestradiol dipropionate injections; weeks 10-12, testosterone terone propionate implants + oil injections; weeks 13-15, testosterone propionate implants + dihydrotestosterone propionate injections.

Cryomicroscopic observations of cattle embryos during freezing and thawing.

A cryomicroscope was used to observe changes in the appearance of day 6 1 2 to 7 1 2 cattle embryos during cooling and warming in 1.4M glycerol/PBS. Embryos were cooled at various rates between 0.

Duration of copulation and fertility in the mink, Mustela vison.

In mink, restricting the duration of copulation ( View Article and Find Full Text PDF

Studies in the electron microscope of the adoral zone of membranelles of the rumen ciliate entodinium caudatum using the technique of negative staining.

The structure of the organelles situated beneath the kinetosomes in the adoral zone of membranelles of the rumen ciliate Entodinium caudatum have been investigated in the electron microscope using the technique of negative staining. Each kinetosome was joined to a sub-kinetosomal plate and these plates were joined together in rows which in turn were more loosely linked to form a sheet. The structure or these plates is described and their relationship to similar structures in other protozoa is discussed.

A study in the light and electron microscope of the extruded peristome and related structures of the rumen ciliate entodinium caudatum.

A study in the light and electron microscope of sections of the rumen ciliate Entodinium caudatum was undertaken in an attempt to elucidate the structure of the peristome when in the extruded state The conformation of the ciliary band on the peristome and the structure of the lining of the buccal cavity are described. The structure and position of a tuft of specialized sheet like extensions of the cell surface is also described.

Electron microscopy of the rumen ciliate Entodinium caudatum, with special reference to the engulfment of bacteria and other particulate matter.

A study in the electron microscope of thin sections of the rumen ciliate Entodinium caudatum was undertaken in an attempt to elucidate the mode of engulfment of particulate matter. This protozoon engulfed bacteria, polystyrene latex particles and olive oil into membrane-lined vesicles in the protozoal endoplasm. Particles of palladium black were also taken up into the endoplasm, but due to the toxic nature of this material it was not possible to demonstrate vesicle formation with certainty.

'Phosphatido-peptide'-like complexes formed by the interaction of calcium triphosphoinositide with protein.

1. The sodium salt of triphosphoinositide partitions in the upper polar phase in a biphasic chloroform-methanol-water system similar to that of Folch et al. (1957).