Intersubgeneric hybridization of soybeans with a wild perennial species,Glycine clandestina Wendl

Summary The exploitation of wild perennial species of subgenus Glycine has been formidable in soybean breeding programs because of extremely poor crossability and an early pod abortion. The combination of gibberellic acid application to hybridized gynoecia and improved seed culture media formulations resulted in a new intersubgeneric hybrid between Glycine max (L.) Merr. (2n=40) and G. clandestina Wendt. (2n=40). Of the 31 immature seeds cultured, 1 regenerated 21 plants through organogenesis while the remaining 30 failed to germinate. All the regenerated plants were similar morphologically, carried expected 2n=40, possessed hybrid isozyme patterns and were completely sterile. Complete absence of chromosome pairing was observed in 40.9% sporocytes. The occurrence of 1 to 6 loosely paired rod bivalents suggests some possibilities of allosyndetic pairing. Hybrid plants set aborted pods after backcrossing to G. max.     

The use of slotted grids for electron microscopic radioautography

A method for electron microscopic radioautography on slotted grids is presented which allows examination of the distribution of silver grains over sections of entire structural units without interference by grid bars. Tissue sections of a size such as to fit the opening of the grid slot are placed on slides coated with a Formvar film of sufficient strength to permit transfer of the completed radioautograph onto the grid and to support it over the slot. Sections are block stained prior to radioautography to minimize the risk of loss of the radioautograph during the procedure.     

Characteristics of the ultrastructural organization of the nuclei of somatic cell hybrids

A study was made of the ultrastructure of cell nuclei of two types of hybrid clones obtained from the fusion of Chinese hamster with human skin fibroblasts, and from that of mouse hepatoma cells with mink fibroblasts. In cell nuclei of the eight hybrid clones deep invaginations of the inner membrane, not characteristic of the parent cells, were revealed. Analysis of serial sections, and application of electron microscopic radioautography and histochemistry have suggested that these structures are associated with the nuclear envelope which is necessary for regulating the superfluous chromosome localization in the hybrid nucleus.     

Canalicular system of enterocytes at rest and its changes during lipid absorption

A study was made of the structural changes in different organoids of enterocytes of the rat small intestine at "rest" and during lipid absorption using ultrathin sections, impregnation with Ur-Pb-Cu, and continuous impregnation with OsO4. With the latter technique a specific canalicular system was found in the enterocytes, which we failed to observe on ultrathin sections. During lipid absorption the canalicular system underwent fragmentation. The vesicules on the trans-surface of the Golgi apparatus were enlarged, and the number of flattened cisterns was significantly lower. The changes in cellular organoids and their interrelations observed in the present study support the earlier hypothesis of the resynthesis of triglycerides within the enterocytes, the formation of chylomicrons and their transfer into the intercellular space.     

The effect of repeated administration of insulin on pain threshold and gamma-aminobutyric acid level in mouse brain

In experiments on male Albino-Swiss mice weighing 18-22 g insulin given in doses of 2 i.u./kg caused no change in the time of reaction to pain, while the same dose administered daily for 7 days potentiated the analgesic action of morphine (3 mg/kg s.c.). Glucose caused no change in this effect of insulin. After 14 days of insulin treatment the time of reaction to pain in the animals subjected to the action of morphine returned to its initial value. Twenty-four hours after the last administration of morphine the level of gamma-aminobutyric acid (GABA) was found to be decreased in the animals receiving insulin with glucose. These results suggest that the central action of insulin is dependent not only on hypoglycaemia produced by it, but may be due also to its direct action on the central structures and an indirect action mediated by its effect on other neurotransmitter systems.     

Motor asymmetry of the forelimbs of the rat

Preference was studied of one of the forelimbs during performance of different manipulating movements in white rats. High degree of "handedness" was observed in all studied movements. However it was not absolute--no animals performed all movements by one and the same limb. Degree and character of "handedness" were different for different movements, though the number of "righthanded" rats in most tests as a whole exceeded the number of "lefthanded" ones. The "handedness" depends on the individuality of the animal, the character of the motor task, learning and interference of different motor tasks during training.