Carbohydrates,lipids and lipoproteins and islet changes in diabetes with superimposed myocardial infarction

Short-term metabolic and concomitant morphologic effects of streptozotocin diabetes on isoproterenol-induced myocardial infarction was studied in Wistar rats, Of particular significance was the observation that myocardial infarction in concert with diabetes brought about a distinctive exacerbation of the severity and complexity of the histopathological lesions. Of all the biochemical parameters, serum glucose and free fatty acids registered maximum elevation and serum lactate and cardiac glycogen levels a maximum reduction. Among the lipoproteins, an inverse relationship was found between high density lipoproteins and low density and very low density lipoproteins; while high density lipoproteins, ratio of high density lipoprotein to low density lipoprotein and the percentage of high density lipoprotein were decreased, there was a significant increase in low density lipoprotein concentration and percentage values of low density and very low density lipoproteins. In diabetes, the B cell of the endocrine pancreas depicted selective necrosis. Loss of insulin granules and wide-spread necrobiosis of cellular elements of the pancreatic islets were observed, respectively, in myocardial infarction and in diabetes plus myocardial infarction combinations. Pathological evidence of chemical-induced mild toxicity was present in the exocrine parenchyma. Mitotic features and the presence of centroacinar cells in the damaged Langerhans’ islets supposedly formed the basis of regeneration of the tissue in diabetes, with or without vascular complications     

Releaser and primer pheromones in Collembola

In Collembola, pheromones appear to be present in the faecal pellets. Pheromone release after cessation of faeces production points to the digestive tract as a possible site of biosynthesis.During the pre-moulting periods Collembola do not react to pheromones, possibly due to their low activity at that time, whereas the production of the pheromones continues.Starvation periods of up to 14 days diminish pheromone release but do not cause complete cessation. Production per animal seems to decrease at increasing densities.The effect of pheromones on the reproductive efficiency of Collembola is discussed in the context of their physiological and behavioural ecology.     

Regulation by kinetin and abcisic acid of correlative senescence in relation to grain maturation,source-sink relationship and yield of rice (Oryza sativa L.)

When kinetin was applied to the source organ (flag leaf) of rice (Oryza sativa L. cv. Ratna), foliar senescence was delayed and grain yield per plant (as evidenced by grain weight, grain/straw weight ratio and 1,000 grain growth) was increased through the increase of sink activity (increase in dry weight of the grains/plant), duration of sink capacity as well as photosynthetic ability of the glumes (as determined by the chlorophyll content of the glumes of the developing grains). However, application of kinetin to the sink organs (fruits), promoted senescence of the source but increased the yield by increasing the sink capacity and 1,000 grain growth mostly at the earlier stage of reproductive development. Lower sterility percentage was associated with higher grain yield of the plant by kinetin treatments. ABA applied either to the source or the sink promoted leaf senescence and reduced the grain yield by reducing the sink activity, harvest index, sink capacity duration and increasing the sterility percentage. Thousand grain dry weight at harvest did not vary significantly amongst the treatments. It was concluded that nutrient drainage was associated with the correlative influence of fruit on the monocarpic senescence of rice plant and that a competetion for differential allocation of cytokinin and ABA in the source and sink organs initiates this senescence syndrome.     

掷孢菌科的研究——Ⅲ.不同掷孢酵母属产掷孢子的能力及担子菌酵母形成特大厚垣孢子的规律

本文以分离自中国的大量掷孢酵母为材料,研究了不同属的掷孢酵母生掷孢子的能力,以及此能力的持久性,发现属间差异很大。此外还报道了142株不同酵母的产厚垣孢子的情况,发现与担子菌有关的4属酵母在接近致死温度时,都会出现特大厚垣孢子如红掷孢酵母(Sporobolomyces),布勒掷孢酵母(Bullera),红酵母(Rhodotorula)与隐球酵母(cryptococcus),而属于子囊菌的酵母属(Saccharomyces)则无此现象,从而对某些接近担子菌的酵母又增加了新的认识。     

白鲟消化道形态学与组织学的初步观察

白鲟消化道具有肉食性鱼类的典型特征,其口咽腔结构既适合捕食又适合吞食与滤食水生动物。咽后消化道可分为食道、胃后行支、胃前行支、小肠、瓣肠、直肠与肛门。幽门盲囊似一致密器官,小肠与瓣肠连接处有一特殊淋巴器官,肛门两侧有腹孔。白鲟口咽腔被覆层扁平上皮,上皮内有味蕾分布。咽后消化道组织分层为粘膜(无粘膜肌层)、粘膜下层(小肠及瓣肠前部无)、肌层与外膜。粘膜上皮为单层柱状上皮,由纤毛柱状细胞、一般柱状细胞和杯状细胞组成,其间还散在有颗粒细胞和游走细胞。食道后部与胃的一般柱状细胞为分泌粘液的细胞,肠内的一般柱状细胞为吸收细胞。胃后行支及部分前行支固有膜内有消化腺,其余各部的固有膜为致密层。小肠前中部粘膜形成蜂窝状粘膜窦,无肠腺。除食道前部肌层中有横纹肌外,其余部的肌层均为平滑肌。外膜内结缔组织有的致密有的疏松,外膜表面细胞柱状或立方形或扁平。     

Initiation and solicitation in male-female grooming in a wild Japanese macaque troop on yakushima island

Grooming initiation among adult males and females of a Japanese macaque troop was analyzed during the non-mating season. Some gestures (“solicitation”) elicited grooming from partners at a high rate. Grooming initiation patterns were divided into two main types: (1) a male often solicited a female to groom him immediately after approaching her and was groomed by her; and (2) a female approached an alpha male selectively, and immediately groomed him. After a female groomed a male, she rarely solicited him to groom her and instead often moved away from him. These results indicated that males were motivated to be groomed, while females were more highly motivated to groom. Sex differences in grooming motivation can be explained by sex differences in the benefit to be groomed.     

Nolleria pulicis N. Gen., N. Sp. (Microsporida: Chytridiopsidae), a Microsporidian Parasite of the Cat Flea, Ctenocephalides felis (Siphonaptera: Pulicidae)

A new species of microsporidium, Nolleria pulicis, is described and named here from the cat flea, Ctenocephalides felis. The genus Nolleria is created and placed within the family Chytridiopsidae. The family is slightly modified to accommodate certain features of intracellular development seen in N. pulicis, which is otherwise very similar to other species in the family Chytridiopsidae. Sporulation is described from ultrastructural analysis of infected midgut epithelial cells of adult C. felis. The term “multiple division by vacuolation” is proposed for describing sporogony as it occurs in this species and certain related species of microsporidia. The probable mode of transmission and apparent absence of merogony are discussed.     

Community composition and soil properties in northern Bolivian savanna vegetation

Abstract. Direct gradient analysis (Canonical Correspondence Analysis) of northern Bolivian savanna vegetation revealed correlations between the composition of plant communities and physical and chemical soil properties. Cover/abundance values for 193 species from 27 sites were related to data on eight soil factors. A water-regime variable and the percentage of sand and silt were correlated with the first axis of the species-environment biplot and explained most of the variation in community composition. Along this axis, species and sites of flood-plain vegetation were separated from sites not affected by flooding rivers. The second axis of the biplot was correlated with soil-chemical variables, namely extract-able phosphate, base saturation, organic carbon, pH, and effective cation exchange capacity. Part of the variation in community composition can be explained by these soil nutrient variables. Grassland communities were separated from woody vegetation along the soil nutrient gradient, and floodplain communities of white-water rivers from those of clear-water rivers. The results of the gradient analysis indicate that the soil texture-moisture gradient is the prime factor determining the variation in the floristic composition of the savanna communities examined, and that, in addition, the soil nutrient gradient accounts for some of the variation.     

Ethanol Inhibits Basic Fibroblast Growth Factor-Mediated Proliferation of C6 Astrocytoma Cells

Abstract: Early ethanol exposure alters the proliferative activity of glial and neuronal precursors in the developing CNS. The present study tests the hypothesis that ethanol-induced alterations in cell proliferation result from interference with growth factors. An in vitro model of astroglia (C6 astrocytoma cells) was used to study the effects of ethanol on proliferation mediated by basic fibroblast growth factor (bFGF). bFGF stimulated the proliferation of C6 cells. This bFGF-enhanced proliferation was evident by increases in total cell number, DNA synthesis (as measured by [³H]thymidine incorporation), and the number of cells that took up bromodeoxyuridine. A synthetic peptide that specifically blocked the binding of bFGF to its high-affinity receptor completely abolished the proliferation-promoting effect of bFGF. The action of another mitogen for C6 cells, insulin-like growth factor-1, was not affected by this peptide. Therefore, the bFGF-stimulated proliferation was mediated through a specific bFGF receptor. Ethanol inhibited bFGF-mediated proliferation in a concentration-dependent manner. Ethanol concentrations of 100 and 200 mg/dl partially inhibited bFGF-mediated proliferation (by 58 and 74%, respectively), whereas concentrations of ≥400 mg/dl completely abolished the growth-stimulating effect of bFGF. Our data show that ethanol alters proliferative activity of C6 cells by disrupting the action of bFGF. The target of ethanol neurotoxicity is a receptor-mediated activity. bFGF can affect cell proliferation by a non-receptor-mediated intracellular pathway, but ethanol does not have an impact on this pathway.     

Ferritin gene organization: Differences between plants and animals suggest possible kingdom-specific selective constraints

Ferritin, a protein widespread in nature, concentrates iron ∼10¹¹–10¹²-fold above the solubility within a spherical shell of 24 subunits; it derives in plants and animals from a common ancestor (based on sequence) but displays a cytoplasmic location in animals compared to the plastid in contemporary plants. Ferritin gene regulation in plants and animals is altered by development, hormones, and excess iron; iron signals target DNA in plants but mRNA in animals. Evolution has thus conserved the two end points of ferritin gene expression, the physiological signals and the protein structure, while allowing some divergence of the genetic mechanisms. Comparison of ferritin gene organization in plants and animals, made possible by the cloning of a dicot (soybean) ferritin gene presented here and the recent cloning of two monocot (maize) ferritin genes, shows evolutionary divergence in ferritin gene organization between plants and animals but conservation among plants or among animals; divergence in the genetic mechanism for iron regulation is reflected by the absence in all three plant genes of the IRE, a highly conserved, noncoding sequence in vertebrate animal ferritin mRNA. In plant ferritin genes, the number of introns (n= 7) is higher than in animals (n= 3). Second, no intron positions are conserved when ferritin genes of plants and animals are compared, although all ferritin gene introns are in the coding region; within kingdoms, the intron positions in ferritin genes are conserved. Finally, secondary protein structure has no apparent relationship to intron/exon boundaries in plant ferritin genes, whereas in animal ferritin genes the correspondence is high. The structural differences in introns/exons among phylogenetically related ferritin coding sequences and the high conservation of the gene structure within plant or animal kingdoms suggest that kingdom-specific functional constraints may exist to maintain a particular intron/exon pattern within ferritin genes. In the case of plants, where ferritin gene intron placement is unrelated to triplet codons or protein structure, and where ferritin is targeted to the plastid, the selection pressure on gene organization may relate to RNA function and plastid/nuclear signaling. Received: 25 July 1995 / Accepted: 3 October 1995