The nervous system of Tricladida. I. Neuroanatomy ofProcerodes littoralis (Maricola,Procerodidae): An immunocytochemical study

The organization of the nervous system ofProcerodes littoralis (Tricladida, Maricola, Procerodidae) was studied by immunocytochemistry, using antibodies to authentic flatworm neuropeptide F (NPF) (Moniezia expansa). Compared to earlier investigations of the neuroanatomy of tricladid flatworms, the pattern of NPF immunoreactivity inProcerodes littoralis reveals differences in the following respects: 1. Shape and structure of the brain. 2. Number and composition of longitudinal nerve cords. 3. Shape of branches of, and transverse connections between, main ventral nerve cords. 4. Composition of the pharyngeal nervous system. The rich innervation by NPF immunoreactive (IR) fibres and cells of the subepithelial muscle layer, the pharynx musculature and the musculature of the male copulatory apparatus indicates a neurotransmitter or neuromodulatory influence on muscular activity.     

滇南及滇东南胶孔菌复合群的分类地理研究

报道了我国滇南及滇东南热带、亚热带胶孔菌复合群众路线属６种,其中瘤丝牛肝菌Ｆｉｌｏｂｏｌｅｔｕｓ ｖｅｒｒｕｃｕｌｏｓｕｓ Ｐ．Ｇ．Ｌｉｕ和滇丝牛肝菌Ｆ．ｙｕｎｎａｎｅｎｓｉｓ Ｐ．Ｇ．Ｌｉｕ是新种,紫兰小菇Ｍｙｃｅｎａ ｖｉｏｌａｃｅｌｌａ（Ｓｐｅｑ．）Ｓｉｎｇ。是我国新纪录种;新种附有拉丁文描术和插图,新纪录和附有形态解剖图。本文所引证标本均存放于中国科学院昆明植物研究所隐花植物标本馆（ＨＫＡ     

Photoaffinity cross-linking of F1ATPase from spinach chloroplasts by 3''-arylazido-β-alanyl-8-azido ATP

UV irradiation of the ATPase (CF₁) from spinach chloroplasts in the presence of 3'-arylazido-β-alanyl-8-azido ATP (8,3'-DiN₃ATP) results in a nucleotide-dependent inactivation of the enzyme and in a nucleotide-dependent formation of -β cross-links. The results demonstrate an interfacial localization of the nucleotide binding sites on CF₁.     

Superoxide dismutase,catalase, and U78517F attenuate neuronal damage in gerbils with repeated brief ischemic insults

Repeated ischemic insults at one hour intervals result in more severe neuronal damage than a single similar duration insult. The mechanism for the more severe damage with repetitive ischemia is not fully understood. We hypothesized that the prolonged reperfusion periods between the relatively short ischemic insults may result in a pronounced generation of oxygen free radicals (OFRs). In this study, we tested the protective effects of superoxide dismutase (SOD) and catalase (alone or in combination), and U78517F in a gerbil model of repetitive ischemia. Three episodes (two min each) of bilateral carotid occlusion were used at one hour intervals to produce repetitive ischemia. Superoxide dismutase and catalase were infused via osmotic pumps into the lateral ventricles. Two doses of U78517F were given three times per animal, one half hour prior to each occlusion. Neuronal damage was assessed 7 days later in several brain regions using the silver staining technique. The Mann-Whitney U test was used for statistical comparison. Superoxide dismutase showed significant protection in the hippocampus (CA4), striatum, thalamus and the medial geniculate nucleus (MGN). Catalase showed significant protection in the striatum, hippocampus, thalamus, and MGN and the substantia nigra reticulata. Combination of the two resulted in additional protection in the cerebral cortex. Compared to the controls, there was little protection with a dose of 3 mg/kg of U78517F. There was significant protection with a dose of 10 mg/kg in the hippocampus (CA4), striatum, thalamus, medial geniculate nucleus and the substantia nigra reticulata. The significant protection noted with SOD, catalase or U78517F with repeated ischemia supports, the hypothesis that OFRs may play a role in neuronal damage in repeated cerebral ischemia.     

甘薯象空间格局及抽样技术研究

通过空间分布型指数分析,甘薯象对薯块、著株危害空间分布型为随机分布或均匀分布;同时确定了理论抽样数     

The radiosensitivity of spermatogonial stem cells in C3H/101 F1 hybrid mice

The radiosensitivity of spermatogonial stem cells of C3H/HeH × 101/H F₁ hybrid mice was determined by counting undifferentiated spermatogonia at 10 days after X-irradiation. During the spermatogenic cycle, differences in radiosensitivity were found, which were correlated with the proliferative activity of the spermatogonial stem cells. In stage VIII_irr, during quiescence, the spermatogonial stem cells were most radiosensitive with a D₀ of 1.4 Gy. In stages XI_irr−V_irr, when the cells were proliferatively active, the D₀ was about 2.6 Gy. Based on the D₀ values for sensitive and resistant spermatogonia and on the D₀ for the total population, a ratio of 45:55% of sensitive to resistant spermatogonial stem cells was estimated for cell killing.

When the present data were compared with data on translocation induction obtained in mice of the same genotype, a close fit was obtained when the translocation yield (Y; in % abnormal cells) after a radiation dose D was described by Y = e^τD, with τ = 1 for the sensitive and τ = 0.1 for the resistant spermatogonial stem cells, with a maximal e^τD of 100.     

Molecular chaperones and the biogenesis of mitochondria and peroxisomes

Summary— A review of the proteinaceous machinery involved in protein sorting pathways and protein folding and assembly in mitochondria and peroxisomes is presented. After considering the various sorting pathways and targeting signals of mitochondrial and peroxisomal proteins, we make a comparative dissection of the protein factors involved in: i) the stabilization of cytosolic precursor proteins in a translocation competent conformation; ii) the membrane import apparatus of mitochondria and peroxisomes; iii) the processing of mitochondrial precursor proteins, and the eventual processing of certain peroxisomal precursor, in the interior of the organelles; and iv) the requirement of molecular chaperones for appropriate folding and assembly of imported proteins in the matrix of both organelles. Those aspects of mitochondrial biogenesis that have developed rapidly during the last few years, such as the requirement of molecular chaperones, are stressed in order to stimulate further parallel investigations aimed to understand the origin, biochemistry, molecular biology and pathology of peroxisomes. In this regard, a brief review of findings from our group and others is presented in which the role of the F₁-ATPase α-subunit is pointed out as a molecular chaperone of mitochondria and chloroplasts. In addition, data are presented that could question our previous indication that the immunoreactive protein found in the rat liver peroxisomes is due to the presence of the F₁-ATPase α-subunit.     

Neither Moderate Hypoxia nor Mild Hypoglycaemia Alone Causes Any Significant Increase in Cerebral [Ca2±i: Only a Combination of the Two Insults Has This Effect.: A 31P and 19F NMR Study

(1) The energy state and free intracellular calcium concentration ([Ca^2±_i) of super-fused cortical slices were measured in moderate hypoxia (～65 μM O₂), in mild hypoglycaemia (0.5 mM glucose), and in combinations of the two insults using ¹⁹F and ³¹P NMR spectroscopy. (2) Neither hypoxia nor hypoglycaemia alone caused any significant change in [Ca^2±_i. Hypoxia caused a 40% fall in phosphocreatine (PCr) content but not in ATP level, and hypoglycaemia produced a slight fall in both (as expected from previous studies). These changes in the energy state recovered on return to control conditions. (3) A combined sequential insult (hypoxia, followed by hypoxia plus hypoglycaemia) produced a 100% increase in [Ca^2±, and a decrease in PCr level to ～25% of control. The reverse combined sequential insult (hypoglycaemia, followed by hypoglycaemia plus hypoxia) had the same effect. On return to control conditions there was some decrease in [Ca^2±_i and a small increase in PCr content, but neither recovered to control levels. (4) Exposure of the tissue to the combined simultaneous insult (hypoxia plus hypoglycaemia) immediately after the control spectra had been recorded resulted in a fivefold increase in [Ca^2±_i and a similar decrease in PCr level to 20–25% of control. There was little if any change of [Ca^2±_i or PCr level on return to control conditions. (5) These results are discussed in terms of metabolic adaptation of some but not all of the cortical cells to the single type of insult, which renders the tissues less vulnerable to the combined insult.