Transmitter-Induced Calcium Responses Differ in Astrocytes Acutely Isolated from Rat Brain and in Culture

Abstract: Glial fibrillary acid protein (GFAP)-positive astrocytes isolated from the cerebral cortices of 3–10-day-old rats frequently showed increased intracellular Ca²⁺ concentration responses to l -glutamate and glutamate analogues. However, few of the acutely isolated cells responded to ATP, and no such cells responded to serotonin [5-hydroxytryptamine (5-HT)]. The same cell that failed to respond to ATP or 5-HT often responded to glutamate. Culturing acutely isolated cells in media containing horse serum decreased Ca²⁺ responses to glutamate but increased the responses to ATP and induced responses to 5-HT. In primary cultures prepared from the cerebral cortices of 1-day-old rats and cultured in horse serum, fewer of the cells responded to glutamate, but almost all cells responded to ATP and 5-HT. The lack of, or limited response to, 5-HT or ATP in the acutely isolated cells seems unlikely to be due to selective damage to the respective receptors because acutely isolated GFAP-negative cells showed responses to ATP, several different proteases and mechanical dissociation yielded cells that also responded to glutamate but not to ATP, and exposure of primary cultures to papain did not abolish Ca²⁺ responses to several transmitters. The responses of the acutely isolated cells to glutamate but limited or lack of responses to ATP and 5-HT also correspond to what has been seen so far for astrocytes in situ. Thus, the present studies provide direct evidence that some of the receptors seen in primary astrocyte cultures may reflect a response to culture conditions and that, in the context of the relevant information so far available, acutely isolated astrocytes seem to reflect better the in vivo state.     

为害枣树一菱纹叶蝉新种

为害枣树一菱纹叶蝉新种蔡平（安徽农学院园艺系合肥２３００３６）崔士英（河北师范大学生物系石家庄０５００１６）葛钟麟（安徽农学院植保系合肥２３００３６）菱纹叶蝉属（Ｈｉｓｈｉ。。ｏｎｕｓＩｓｈｉｈａｒａ。１９５３）隶属于同翅目（ＨｏｍｏＰｔｅｒａ）ｎ十...     

Variation in heat shock proteins within tropical and desert species of poeciliid fishes

The 70-kilodalton heat shock protein (hsp70) family of molecular chaperones, which contains both stress-inducible and normally abundant constitutive members, is highly conserved across distantly related taxa. Analysis of this protein family in individuals from an outbred population of tropical topminnows, Poeciliopsis gracilis, showed that while constitutive hsp70 family members showed no variation in protein isoforms, inducibly synthesized hsp70 was polymorphic. Several species of Poeciliopsis adapted to desert environments exhibited lower levels of inducible hsp70 polymorphism than the tropical species, but constitutive forms were identical to those in P. gracilis, as they were in the confamilial species Gambusia affinis. These differences suggest that inducible and constitutive members of this family are under different evolutionary constraints and may indicate differences in their function within the cell. Also, northern desert species of Poeciliopsis synthesize a subset of the inducible hsp70 isoforms seen in tropical species. This distribution supports the theory that ancestral tropical fish migrated northward and colonized desert streams; the subsequent decrease in variation of inducible hsp70 may have been due to genetic drift or a consequence of adaptation to the desert environment. Higher levels of variability were found when the 30- kilodalton heat shock protein (hsp30) family was analyzed within different strains of two desert species of Poeciliopsis and also in wild-caught individuals of Gambusia affinis. In both cases the distribution of hsp30 isoform diversity was similar to that seen previously with allozyme polymorphisms.      

内皮素－1对缺氧肺动脉平滑肌细胞的增殖作用

内皮素（ＥＴ）是至今所发现的最强的内源性血管收缩肽,近年来发现ＥＴ－１能促进血管平滑肌细胞增殖。本研究表明ＥＴ－１对缺氧培养的肺动脉平滑肌细胞（ＰＡＳＭＣ）有剂量依赖的增殖作用,缺氧可促进ＰＡＳＭＣ的ＤＮＡ合成且增加ＥＴ－１的丝裂原作用。ＥＴ－１的丝裂原作用主要由其Ａ型受体（ＥＴＲ＿Ａ）所介导,ＥＴＲ＿Ａ的特异拮抗剂ＢＱ１２３可显著抑制缺氧以及缺氧与ＥＴ－１协同所产生的增殖作用,而且发现ＥＴＲ＿Ａ在缺氧培养的ＰＡＳＭＣ中的表达显著高于常氧对照组ＰＡＳＭＣ。本研究表明ＥＴ－１参与了缺氧性肺动脉结构重组,而缺氧可增强ＰＡＳＭＣ对ＥＴ－１的增殖反应性。     

中国蜘蛛抱蛋属一新记录种——博格纳蜘蛛抱蛋

报道了产自中国云南喀斯特地区的蜘蛛抱蛋属一新记录种——博格纳蜘蛛抱蛋（Aspidistra bogneri H.-J.Tillich）。该种以前报道仅产于越南宁平省菊芳国家公园（Ninh Binh,Cuc Phuong National Park）,本次是中国首次记录。对该种的特征进行了详细描述并提供了彩色图片,凭证标本存放于中国科学院昆明植物研究所标本馆（KUN）。     

高粱泡的生长调控与结实状况

高粱泡(Rubus lambertionus Ser.)是一种有利用价值的野生果树资源。其优点为:(1)结果早,产量高,亩产量可达500kg以上;(2)适应性广,耐瘠薄,是开发利用低山丘陵的优良资源植物;(3)果实营养丰富,酸味纯正,尤其是所含红色素稳定性好,是加工果汁饮料的优质添加剂;(4)果实采收期在11月中旬到12月底,此时气温低,有利于浆果加工和贮藏,并可利用农闲季节的劳动力。上述特点表明,高粱泡有很好的开发利用前景。但本种在野生状态下蔓生性强,多刺,并具有枝顶生根的习性,因而树形紊乱而松散,栽培时搭架困难,植株占地面积大,而单位面积产量不易提高。为了便于操作管理和提高产量,减少栽培成本,增进经济效益,我们于1990～1991年进行了生长和株形调控试验,     

红细胞生成刺激素(EPO)的纯化

 本文用中空纤维柱超滤浓缩尿,再经离子交换层析、聚焦层析、凝胶过滤和制备型聚丙烯酰胺凝胶电泳(PAGE)-层析等四步从15L再生障碍性贫血患者尿中获得约2mg EPO制品。比活性达10 300U/mg蛋白。该制品在分析型PAGE中呈一条区带。     

Characterization of the IS895 family of insertion sequences from the cyanobacterium Anabaena sp. strain PCC 7120.

A family of repetitive elements from the cyanobacterium Anabaena sp. strain PCC 7120 was identified through the proximity of one element to the psbAI gene. Four members of this seven-member family were isolated and shown to have structures characteristic of bacterial insertion sequences. Each element is approximately 1,200 bp in length, is delimited by a 30-bp inverted repeat, and contains two open reading frames in tandem on the same DNA strand. The four copies differ from each other by small insertions or deletions, some of which alter the open reading frames. By using a system designed to trap insertion elements, one of the elements, denoted IS895, was shown to be mobile. The target site was not duplicated upon insertion of the element. Two other filamentous cyanobacterial strains were also found to contain sequences homologous to IS895.