Significance of the inactivation of transport in thermal death of Escherichia coli.

Cells of Escherichia coli ML308-225, harvested from the exponential phase, were heated in 50 mM potassium phosphate, and the loss in viability and inability to transport lactose, proline, and alpha-methylglucoside was compared. After cells were heated at 48 degrees C for 15 min, there was a 16% loss in viability and a similarly small reduction in the steady-state accumulation of lactose at 25 degrees C. The initial rates of lactose and proline transport were severely inhibited by heating at either 48 or 50 degrees C, but substantial recovery occurred within 5 to 7 min at 25 degrees C. Heating at 50 degrees C for 15 min caused an 86% loss in viability, but only a 53% decrease in the steady-state accumulation of lactose and only a 24% reduction in the initial rate of alpha-methylglucoside uptake. Twice as much alpha-methylglucoside was accumulated at 50 degrees C as at 25 degrees C. Although alpha-methylglucoside phosphate leaked from the cells at 50 degrees C, the concentration retained within the cells was about 500 times that externally, when only about 14% of the cells were viable. Overall, these results indicate that cells made nonviable by heating at 50 degrees C still have significant membrane integrity.     

Conscious Brain-to-Brain Communication in Humans Using Non-Invasive Technologies

Human sensory and motor systems provide the natural means for the exchange of information between individuals, and, hence, the basis for human civilization. The recent development of brain-computer interfaces (BCI) has provided an important element for the creation of brain-to-brain communication systems, and precise brain stimulation techniques are now available for the realization of non-invasive computer-brain interfaces (CBI). These technologies, BCI and CBI, can be combined to realize the vision of non-invasive, computer-mediated brain-to-brain (B2B) communication between subjects (hyperinteraction). Here we demonstrate the conscious transmission of information between human brains through the intact scalp and without intervention of motor or peripheral sensory systems. Pseudo-random binary streams encoding words were transmitted between the minds of emitter and receiver subjects separated by great distances, representing the realization of the first human brain-to-brain interface. In a series of experiments, we established internet-mediated B2B communication by combining a BCI based on voluntary motor imagery-controlled electroencephalographic (EEG) changes with a CBI inducing the conscious perception of phosphenes (light flashes) through neuronavigated, robotized transcranial magnetic stimulation (TMS), with special care taken to block sensory (tactile, visual or auditory) cues. Our results provide a critical proof-of-principle demonstration for the development of conscious B2B communication technologies. More fully developed, related implementations will open new research venues in cognitive, social and clinical neuroscience and the scientific study of consciousness. We envision that hyperinteraction technologies will eventually have a profound impact on the social structure of our civilization and raise important ethical issues.     

下丘脑外侧区注射TRH对大鼠胃酸分泌的影响

本文采用连续收集胃腔灌流法,观察下丘脑外侧区(LHA)注射促甲状腺激素释放激素(TRH)对大鼠胃酸分泌的影响,并分析TRH在LHA促进胃酸分泌的作用机制。结果表明:(1)LHA注射TRH(1μg)明显地刺激胃酸分泌;(2)预先向LHA注射酚妥拉明(10μg)、美多心安(5μg)及胃泌素抗体1μl(1:640)并不影响TRH的泌酸作用,如预先向LHA注射阿托品(5μg)则可消除TRH的泌酸效应;(3)垂体摘除及肾上腺切除均不影响TRH的泌酸作用;(4)隔下迷走神经切断后,LHA注入TRH的泌酸效应仍然出现,但持续时间显著缩短;腹腔交感神经节摘除后,TRH仍能促进胃酸分泌,但分泌量少而平稳。以上结果提示:LHA是TRH中枢泌酸效应的有关结构之一,其中枢机制是通过胆碱能M受体中介的,腹腔交感神经节和膈下迷走神经是TRH泌酸效应的传出途径。前者引起的泌酸反应出现较早且引起泌酸高峰,但持续时间短;后者则引起低平的持续分泌。     

Peptidergic neurons of the crab,Cardisoma carnifex,in defined culture maintain characteristic morphologies under a variety of conditions

Summary Peptidergic neurons dissociated from the neurosecretory cell group, the X-organ, of adult crabs (Cardisoma carnifex) show immediate outgrowth on unconditioned plastic dishes in defined medium. Most of the neurons can be categorized as small cells, branchers or veilers. A fourth type, superlarge, found occasionally, has a soma diameter greater than 40 m and multipolar outgrowth. We report here the effects on morphology that follow alterations of the standard defined culturing conditions. The three common types of neurons are present when cells are grown in crab saline or saline with l-glutamine and glucose (saline medium). Changes of pH between 7.0 to 7.9 have no effect. Osmolarity changes cause transient varicosities in small cells. In some veilers, pits rapidly appear in the veil and then disappear within 35 min. In cultures at 26° C instead of 22° C, veilers extend processes from the initial veil in a pattern similar to branchers, and the processes of adjacent veilers sometimes form appositions. Culturing in higher [K⁺]_o medium ([K⁺]_o=15–110 mM; standard=11 mM) has no long-term effect, but growth is arrested by [K⁺]_o greater than 30 mM. Cultures were also grown in media in which [Ca²⁺]_o ranged from 0.1 M to 26 mM (standard=13 mM). Outgrowth occured from all neuronal types in all [Ca²⁺]_o tested. Thus, the expression of different outgrowth morphologies occurs under a wide variety of culturing conditions.     

Pathogenesis of the delayed phase of Rauscher virus-induced thrombocytopenia

BALB/c (H-2d) mice infected with Rauscher murine leukemia virus (RMuLV) developed two phases of thrombocytopenia: an acute phase, probably due to direct virus-platelet interactions, and a delayed phase, starting 2 to 3 wk after virus injection, which was associated with the infection of megakaryocytes by RMuLV and with the expression of RMuLV gp70 and p30 antigens on platelet membranes. This study was concerned with the pathogenesis of this second phase of thrombocytopenia. During this period, the number of marrow megakaryocytes was increased. A peripheral platelet destruction was further indicated by reduced platelet life span. It was shown that radiolabeled platelets, either normal or infected, were submitted to a more rapid clearance in infected recipients than in normal recipients. This might be due to the splenomegaly observed in infected recipients. However, the immediate clearance of gp70+ platelets was more accelerated in infected recipients with high titers of serum anti-gp70 antibodies than in infected recipients without detectable serum anti-gp70 antibodies. In addition, the passive transfer of anti-RMuLV serum to normal BALB/c mice induced a rapid and specific clearance of previously injected radiolabeled platelets expressing RMuLV antigens. In H-2d mice, viral gp70 antigen expression on platelets correlated with the development of delayed thrombocytopenia; but H-2k strains of mice, although susceptible to RMuLV and expressing RMuLV-related antigens on their platelets, did not develop any anti-RMuLV antibodies nor any delayed thrombocytopenia. These results suggest that specific clearance of gp70+ platelets in the presence of significant amounts of serum antiviral antibodies and nonspecific hypersplenism play a role in the development of delayed thrombocytopenia in RMuLV-infected mice.     

中华白蛉的自育性研究

现场及实验室结果表明,我国黄土高原的大多数中华白蛉(Phlebotomus chinensis)应属自育性品系,它通常在羽化后、吸血前经交配能依靠腹节内脂肪体发育卵泡,一般在产卵后始行吸血。其生理性状是:胃内无血、腹节内有大量块状或条状脂肪体。羽化24小时后,附腺内有暗色颗粒,卵巢内有发育的卵泡。在25℃士1℃下它的生活史分快、慢两型。快型从卵至成虫仅需44—50夭,慢型需要以四龄幼虫滞育,其长短随滞育期而定,最长的滞育期达301天。观察了白蛉幼虫在饥饿状态下对自育性的影响。此外,还比较了吸血白蛉与自育性白蛉的妊卵数。吸血白蛉的妊卵数约较自育性的高出1/5。这种自育性品系的中华白蛉在自然居群约内占92%、主要栖于洞穴内为野栖种类。本文对自育性中华白蛉的生态及其防制策略作了分析和讨论。     

中国拟盘多毛孢属真菌的七个新组合

作者按照Steyaert(1949)和Sutton(1980)的分类观点,对1987—1988年从我国广西、江西、浙江等地采集的Pestalotiopsis属真菌进行了研究,确认了拟盘多毛孢属真菌的7个新组合种,即Pestalotiopsis carveri(Guba)comb nov.,Pestalotiopsis elasticae(Koord.)comb.nov.,Pestalotiopsis langloisii(Guba)comb.nov.,Pestalotiopsis oleandri(Guba)comb.nov.,Pestalotiopsis sinensis(shen)comb.nov.,Pestalotiopsis sydowiana(Bres.)comb.nov.和Pestalotiopsis zahlbruckneriana(Bres.)comb.nov.     

斜胸叶蝉属一新种（同翅目：叶蝉总科：耳叶蝉科）

本文记述耳叶蝉科斜胸叶蝉属一新种:黄缘斜胸叶蝉Epiclinata flavomarinata sp.nov.。标本采自我国西藏。文中描述了新种的外部形态及雄性外生殖器构造特征,并与近似种进行比较,附有主要特征图。模式标本保存于中国科学院动物研究所。