Giemsa stain applied to deplasticized sections to identify pancreatic islet cells

A new application of the Giemsa stain to demonstrate endocrine cells in deplasticized sections of Epon embedded material is described. Its application to the pancreas of Rana temporaria is illustrated. The technique does not require postfixation with OsO4 and is easily performed in 30 min. It allows the easy identification of three types of endocrine cells (A, B, and D). A cells, preferentially located at the islet periphery, stain purple-blue. B cells, which occupy the interior of the islet, display a lilac color. D cells give a strong purple color; they are located both in the periphery of the islets and scattered among acinar cells. Positive identification of the cell types was made by immunocytochemistry and electron microscopy.     

Intergeneric hybrids of Saccharomyces cerevisiae and Zygosaccharomyces fermentati obtained by protoplast fusion

To obtain strains that are able to efficiently produce ethanol from different carbohydrates, mainly cellulose hydrolysates, several species of the genus Candida and a Zygosaccharomyces fermentati strain were examined for their ability to utilize cellobiose and produce ethanol, as well as for their thermotolerance and the possibility of genetic manipulation. Candida obtusa and Zygosaccharomyces fermentati tolerated the maximal temperature for growth, possessed the highest cellobiase activity, and offered the possibility of genetic manipulation, although neither of them proved to be a good producer of ethanol. Intergeneric hybrids of Saccharomyces cerevisiae and Z. fermentati were obtained after protoplast fusion. They were selected as prototrophic strains, after isolation of auxotrophic mutants from Z. fermentati and fusion with an S. cerevisiae strain which was also auxotrophic. The hybrids, which appeared at a frequency of 2 X 10(-7), presented characteristics of both parents, such as resistance to certain drugs and the ability to grow with either cellobiose or lactic acid as the sole carbon source; they were very stable, even under nonselective conditions. These hybrids may have important industrial applications as good fermenting strains.     

Ultrastructure and Host Specificity of Bacteriophages of Streptococcus cremoris, Streptococcus lactis subsp. diacetylactis, and Leuconostoc cremoris from Finnish Fermented Milk "Viili"

"Viili," a fermented milk product, has a firm but viscous consistency. It is produced with traditional mesophilic mixed-strain starters, which have various stabilities in dairy practice. Thirteen morphologically different types of phages were found in 90 viili samples studied by electron microscopy. Ten of the phage types had isometric heads with long, noncontractile tails, two had elongated heads with long, noncontractile tails, and one had a unique, very long elongated head with a short tail. Further morphological differences were found in the tail size and in the presence or absence of a collar, a baseplate, and a tail fiber. To find hosts for the industrially significant phages, we examined the sensitivities of 500 bacterial isolates from starters of the viili. Seven of the phages attacked Streptococcus cremoris strains, three attacked S. lactis subsp. diacetylactis strains, and four attacked Leuconostoc cremoris strains. Some phages differed only in their host specificity. Hosts were not found for 4 of the 13 morphological types of phages.     

Preliminary classification and ecology of dry grassland communities on Ölands Stora Alvar (Sweden)

Four plant community types are described for Öland's Stora Alvar, the limestone plateau of South Öland and preliminary classified syntaxonomically:
(1) Crepis pumila – Allium alvarense ass. (2) Helianthemum oelandicum – Galium oelandicum ass. (3) Gypsophila fastigiata – Globularia vulgaris ass. and (4) Veronica spicata – Avenula pratensis ass. (with two subassociations, the Sedum reflexum and Galium boreale subass.). The ecology of these types is discussed with emphasis on soil depth, frost perturbation and the combined effects of summer drought and grazing intensity.
Various endemic taxa appear to be good character species for the community types described. The typical local ecology of some common species is discussed with the suggestion that they might have formed endemic ecotypes which should be further investigated.
The communities described are very rich in cryptogams. The floristic variation as expressed by the cryptogamic species composition shows largely the same pattern as that shown by the phanerogams.     

Nutritional requirements of a biosurfactant producing strain Rhodococcus sp 51T7

Summary Rhodococcus sp 51T7 produced a trehalose 2,3,4,2 tetraester with surface active properties. When grown on hydrocarbon, cells were highly segmented and accumulated lipid granules in the cytoplasm. Production and glycolipid composition was affected by the nature of the carbon source. Optimal concentrations of sodium nitrate, potassium phosphate and iron were: 2.5, 1.5 and 0.01 g/L respectively. Surfactant production is growth-associated. Production was increased from 0.5 g/L to 3 g/L of glycolipid.     

Some aspects of social problems facing conservation in Brazil

There has been growing concern in Brazil for environmental issues in the last two decades. The conservation policies for Amazonia, which still represents the largest portion of forests of the country, are still based on isolated decisions made in the late 1970's. Among these policies there is, for instance, the plan for the establishment of a net of National Parks, proposed by Wetterberg et al. (1), based on the 'Pleistocene refugia' model. These refugia are areas of high species endemism, representing forest islands formed during the dry periods of the Pleistocene age, constituting the center of evolution and dispersal of Amazonian species (2). A number of parks and biological reserves have since been established and the decreese of laws protecting some elements of the fauna have been implemented. In 1979, studies for a more comprehensive plan for the conservation and development of Brazilian Amazonia were carried out in several institutions committed to research in Amazonia. As a result, several documents were handed to the government, but nothing has yet been implemented. Indeed, no environmental policy for Amazonia will succeed without an effective and comprehensive social plan, and the latter has yet to be formulated.     

Interaction between prostacyclin and colchicine on the gastric mucosa of rat in different experimental ulcer models

The effect of prostacyclin and colchicine on the fundic gastric mucosa of adult female Wistar rats was investigated in stress (immobilization) and indomethacin induced ulcer models. Under prostacyclin treatment the ulcer index decreased significantly in both ulcer models. This effect was inhibited by colchicine. The nuclear volume of fundic epithelial cells increased significantly after application of either type of ulcerogenic stimulus. Prostacyclin did not influence the nuclear volume changes in stress ulcer, while it prevented this phenomenon in indomethacin-induced ulceration. Following colchicine treatment the nuclear volume decreased in both ulcer models. After combined prostacyclin and colchicine treatment the nuclear shrinkage remained unaltered in stress ulcer, while in indomethacin ulcer the nuclear volume decreasing effect of the separately administered drugs disappeared after combined treatment. The latter phenomenon was interpreted as an antagonistic interaction between prostacyclin and colchicine.