绿道及其研究进展

20世纪90年代以来,绿道一直是保护生物学、景观生态学、城市规划和景观设计等多个学科交叉的研究热点和前沿,这种热潮被称为绿道运动.在对绿道的概念进行分析的基础上,探讨了绿道的发展及其主要阶段.分析了绿道的生态功能、休闲游憩功能、经济发展功能、社会文化和美学功能.探讨了绿道规划的方法,及绿道设计的5个方面：绿道宽度的设计、绿道与居住地的距离、绿道与机动车的交叉设计、绿道的路面和配套设施设计、绿道设计的人文关怀.最后回顾了绿道在国内的理论研究和实践进展,分析了绿道对我国自然保护、城市绿地系统和开放空间、文化遗产保护、旅游休闲等方面的启示.     

土壤生态学的理论体系及其研究领域

1　前　言从土壤生态学 (ＳｏｉｌＥｃｏｌｏｇｙ)思想的萌芽[1] 到Ｐｒａｓｏｌｏｖ第一次提出“土壤生态学 ( ｐｅｄｅｃｏｌｏｇｙ)”[2 ]这一术语以来 ,土壤生态学经历了一个较长的奠定和发展时期。 2 0世纪 5 0年代至 70年代 ,国内外一些学者相继出版和发表了土壤生态学的专著和论文[3～ 8] ,标志着它已成为一门独立的学科。但这些工作停留在土壤生物生态学的水平上。 2 0世纪 80年代以来 ,由于经典土壤学和生态学等在解决生产实践和一系列生态环境问题中遇到的困难及生态系统方法论在土壤生态学中的应用 ,才倍受重视 ,突破了土壤生物…     

生物科学的发展与《生物课程标准》

全日制义务教育《生物课程标准》的制订 ,主要是从初中生终身发展的需要、社会需求和生物科学发展 3个方面综合考虑的。此文试从生物科学的发展说明确定课程内容标准的依据。2 0世纪是自然科学发展史上最为辉煌的时代 ,生物科学是自然科学中发展最迅速的学科。因为生物科学与人类生存、人民健康、社会发展密切相关 ,必然成为2 1世纪初的主导学科。在 2 0世纪生物科学的发展中有许多重大突破 ,出现了许多新观念、新思想、新成果和新技术。特别是 2 0世纪 5 0年代以来 ,随着数理科学广泛深入地渗透到生物科学以及一些先进的仪器设备和研究技术…     

中国鸟类生态学的发展与现状

中国鸟类生态学的发展可分三个阶段 :2 0世纪 3 0年代至 5 0年代末的萌芽期 ;60年代初至 70年代末的成长期 ;80年代以来的蓬勃发展期。 1 990年以来 ,繁殖是我国鸟类生态学的最主要研究内容 ,论文数量比例占 2 3 5 3 % ;行为、栖息地、群落和迁徙等方面的研究有明显增长 ;鸟类食性研究的关注程度下降。本文对繁殖、行为、栖息地、种群和群落内容研究现状进行详细分析 ,并提出了今后中国鸟类生态学研究与发展应予以关注的问题     

云南省爬行动物区系及地理区划

1　研究简史1 9世纪末 ,英国、美国及法国等学者先后进入云南考察爬行动物 ,地点主要是滇中及滇西地区。Ａｎｄｅｒｓｏｎ ,Ｊ.(1 879)、Ｂｏｕｌｅｎｇｅｒ,Ｃ .(1 890、1 993、1 90 6)、Ｐｏｐｅ.Ｃ .Ｈ .(1 93 5 )等人均有报道。Ｂｏｕｌｅｎｇｅｒ发表了不少爬行动物新种。Ｐｏｐｅ 1 93 5年在美国纽约出版了“ＴｈｅＲｅｐｔｉｌｅｓｏｆＣｈｉｎａ”书中记述了云南爬行动物 61种。2 0世纪 2 0年代 ,我国学者张玺、成庆泰在云南作过考察 ,1 943及 1 946年曾有报道。 2 0世纪 5 0年代以后 ,赵尔宓、江耀明 (1 966) ,黄祝坚 (1 95 9)有考…     

微生物表面活性剂在工业、农业、医药卫生和环境保护中的应用

在全球工业化蓬勃发展的今天 ,传统的工业技术已相继退出历史舞台 ,取而代之的是新的工业技术例如生物技术。据统计 ,1980年生物技术的世界市场贸易金额是 2 5百万美无 ,1992年增至约 17亿美元 ,2 0世纪末可超过 5 0 0 0亿美元 (Ｍｕｌｌｅｒ等 ,1997)。表面活性剂是当今生物技术中常用的和重要的化合物。它可以减少液体、固体和气体界面间的表面或界面张力 ,使其在水或其他液体中容易混合或扩散 ,因而广泛用于现代工业的几乎每一个领域。仅以美国的化学工业而论 ,2 0世纪 80年代对表面活性剂的需求量就比过去增长 30 0 % (Ｇｒｅｅｋ ,1990…     

叩开现代免疫学大门--琴纳牛痘接种术的发明

天花是由天花病毒引起的烈性传染病 ,患者全身发炎、长满脓疮 ,绝大部分患者在发病后的半个月内死亡 ,侥幸逃生者也要留下一脸麻子。欧、亚、非三大洲都曾几度流行成疫 ,历史上充满了天花大规模流行的悲惨记录。 16世纪欧洲天花蔓延 ,发病人数每年以 10万计 ,病死率高达 2 5 %～ 4 0 %。直到18世纪 ,当时总人口仅为 4 0 0 0万的欧洲 ,每年死于天花的竟达 4 4万 ,其中尤其是 1～ 5岁的儿童 5 0 %～70 %死于该病 ;18世纪中叶一年 ,天花流行得很厉害 ,仅在俄国就死了 2百万人。面对天花 ,人类几乎是束手无策。若干世纪以来 ,天花的广泛流行使人…     

广州绿道系统木本植物多样性与生长特征分析

木本植物是绿道系统中重要的生物组成要素。以广州市域分布的绿道为研究对象, 进行实地调查与统计处理, 并对主要树种组成、开花时间特征、重要值、乡土植物使用情况等开展综合分析。结果表明: (1)广州绿道常见观花木本植物有28种; 全年皆有开花树种, 主要集中在夏季, 如6、7和8月份分别有15、14和12种; (2)优势植物主要有细叶榕、羊蹄甲、高山榕和杧果等, 乡土植物使用率占总数的73%, 但部分乔木树种(如细叶榕)运用频率较高导致群落组成单一; (3)广州绿道树木长势较为良好, 病虫害情况较少, 但也需要加强后期病虫害防护措施; (4)多数常见树种的胸径与冠幅、树高呈现出线性正相关关系。为避免绿道植物群落同质化现象, 建议后续在绿道建设和维护过程中栽植更多种类的乔灌植物, 加强林木病虫害监测与防治, 提升广州市绿道森林景观和生态功能。     

香蕉转基因研究进展

香蕉转基因研究逐渐成为国内外植物分子生物学研究的热点。人们从 2 0世纪 60年代开始就进行了香蕉的组织培养 ,70年代茎尖培养成功 ,近 1 0年来相继在微繁殖、单克隆抗体、分子生物学和遗传转化等方面开展了工作。香蕉转化受体系统已从茎尖发展到胚状体和愈伤组织受体系统 ,遗传转化方法也在不断改进 ,从单一的方法发展为根癌农杆菌感染法与基因枪法的结合。从香蕉组织培养、遗传转化受体系统、基因转化方法、筛选方法的研究等方面进行综述 ,并提出了一些看法。     

微卫星荧光标记基因组扫描

微卫星荧光标记基因组扫描为 2 0世纪 90年代发展起来的一项分子生物学技术 ,在基因定位、个体识别等方面有广泛的应用 .文中对其原理、策略、分析方法及应用作了论述 ,并探讨了它的发展前景 .     

Localization of integrin subunits α6 and β1 during somitogenesis in the long-tailed macaque (M. fascicularis)

The distribution of integrin subunits 6 and 1, and the 61 integrin ligand, laminin, was examined during somitogenesis in developmental stages 11, 13, and 16 in the long-tailed macaque, using peroxidase immunocytochemistry. Within differentiating somites in stage 11, 6 expression was observed in the sclerotome, basal surface of dermamyotomal cells adjacent to the basal lamina and on scattered cells throughout the dermamyotome. In further advanced somites in stages 13 and 16, 6 immunoreactivity become restricted to the myotome, 6 was expressed on mesenchymal core cells within the myocele of undifferentiated epitheliod somites and the ventromedial wall of somites commencing differentiation at each stage. 1 distribution resembled that of 6 in stage 11 somitic tissue, however, it remained present on myotome and sclerotome cells in the later stages, and was also expressed on dermatomal cells in stage 16. Laminin immunoreactivity, while more intense and prevalent than 6 and 1 in each stage examined, occurred on the same somite cell populations as the 2 integrin subunits. These results show a defined distribution of 6 on somitic tissue, and suggest this integrin is involved in somite differentiation. They also support a possible role for 6 in myoblast formation and migration. Overlapping of 1 and laminin immunoreactivity with that of 6 further suggests that 6 paris with 1 as a functional heterodimer for laminin in defined somitic regions.     

BRCA2 is needed for both repair and cell cycle arrest in mammalian cells exposed to S23906, an anticancer monofunctional DNA binder

Repair of DNA-targeted anticancer agents is an active area of investigation of both fundamental and clinical interest. However, most studies have focused on a small number of compounds limiting our understanding of both DNA repair and the DNA damage response. {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906 is an acronycine derivative that shows strong activity toward solid tumors in experimental models. {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906 forms bulky monofunctional DNA adducts in the minor groove which leads to destabilization of the double-stranded helix. We now report that {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906 induces formation of DNA double strand breaks that are processed through homologous recombination (HR) but not Non-Homologous End-Joining (NHEJ) repair. Interestingly, {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906 exposure was accompanied by a higher sensitivity of BRCA2-deficient cells compared to other HR deficient cell lines and by an S-phase accumulation in wild-type (wt), but not in BRCA2-deficient cells. Recently, we have shown that {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906-induced S phase arrest was mediated by the checkpoint kinase Chk1. However, its activated phosphorylated form is equally induced by {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906 in wt and BRCA2-deficient cells, likely indicating a role for BRCA2 downstream of Chk1. Accordingly, override of the S phase arrest by either 7-hydroxystaurosporine (UCN-01) or AZD7762 potentiates the cytotoxic activity of {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906 in wt, but not in BRCA2-deficient cells. Together, our findings suggest that the pronounced sensitivity of BRCA2-deficient cells to {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906 is due to both a defective S-phase arrest and the absence of HR repair. Tumors with deficiencies for proteins involved in HR, and BRCA2 in particular, may thus show increased sensitivity to {"type":"entrez-protein","attrs":{"text":"S23906","term_id":"96914","term_text":"pir||S23906"}}S23906, thereby providing a rationale for patient selection in clinical trials.     

Immunocytochemical localization and ontogenic development of α-melanocyte-stimulating hormone (α-MSH) in the brain of a pleuronectiform fish,barfin flounder

-Melanocyte-stimulating hormone (-MSH) is a pituitary hormone derived by post-translational processing from proopiomelanocortin and is involved in background adaptation in teleost fish. It has also been reported to suppress food intake in mammals. Here, we examined the immunocytochemical localization of -MSH in the brain and pituitary of a pleuronectiform fish, the barfin flounder (Verasper moseri), as a first step in unraveling the possible function of -MSH in the brain. The ontogenic development of the -MSH system was also studied. In the pituitary, -MSH-immunoreactive (ir) cells were preferentially detected in the pars intermedia. In the brain, -MSH-ir neuronal somata were located in the nucleus tuberis lateralis of the basal hypothalamus, and -MSH-ir fibers were located mainly in the telencephalon, hypothalamus, and midbrain. -MSH-ir neuronal somata did not project their axons to the pituitary. The -MSH-ir neurons differed from those immunoreactive to melanin-concentrating hormone. -MSH cells in the pituitary and -MSH-ir neuronal somata in the brain were first detected 1 day and 5 days after hatching, respectively. The distribution of -MSH-ir cells, neuronal somata, and fibers showed a pattern similar to that in adult fish 30 days after hatching. These results indicate that the functions of -MSH in the brain and pituitary are different and that -MSH plays physiological roles in the early development of the barfin flounder. This study was supported in part by grants from the Regional Science Promotion Program Evolutional Research of the Japan Science and Technology Corporation, and the Yumekendo-Iwate Research and Promotion Project of the Iwate Prefectural Government Science and Technology Division to A.T.     

Size fractionation of trace metal species in freshwaters: implications for understanding their behaviour and fate

Data on both the colloid size distributionpresent in freshwaters and the extent to whichtrace metal ions associate with the differentsize fractions within the so-called dissolved phasein these systems are examined. Several keyfeatures are identified: (i) division of totalmetal into particulate and dissolved fractions via a single ca. 450 nm filtrationprocedure provides no useful information, (ii)within the dissolved fraction, a continuum ofparticle sizes exists in the colloidal sizerange in freshwaters, (iii) for the tracemetals Cu, Cd, Zn, Cr, Co, and Ni, the greatestproportion of dissolved trace metals are in the low molecular mass fraction, together withthe largest proportion of DOC, (iv) in allrivers, and in lakes with a low DOC content,the predominant determiner of the sizedistribution of trace metals is the lowermolecular size, more strongly complexing,pedogenic organic matter fraction.     

卵壳的超微结构特征

本文运用扫描电镜研究了美洲鸵鸟,鹂鹋,非洲鸵鸟,普通家鸡,环颈雉,绿头鸭,王企鹅等七种现生鸟蛋壳和更新世安氏鸵鸟蛋壳以及六种白垩纪恐龙蛋壳（长形长形蛋Ｅｌｏｎｇａｔｏｏｌｉｔｈｕｓｅｌｏｎｇａｔｕｓ,安氏长形蛋Ｅｌｏｎｇａｔｏｏｌｉｔｈｕｓａｎｄｒｅｗｓｉ,瑶屯巨形蛋Ｍａｃｒｏｏｌｉｔｈｕｓｙａｏｔｕｎｅｎｓｉｓ粗皮巨形蛋Ｍａｃｒｏｏｌｉｔｈｕｓｒｕｇｕｓｔｕｓ,将军顶圆形蛋Ｓｐｈｅｒｏｏｌｉｔｈ     

Immunocytochemical localization and concentrations of the α and γ subunits of 7S-nerve growth factor in the submandibular gland of the mouse

Summary For unexplained reasons, nerve growth factor (NGF) exists in very high concentrations in the submandibular gland of the mouse. The NGF in the gland, called 7S-NGF, is a non-covalent complex of three protein subunits, named -, - and -NGF. All the known biological activity resides in the -NGF subunit, and previous studies have shown that -NGF is present in much greater concentrations in the male submandibular gland than in the female gland. The higher concentration in the male is due to the fact that -NGF is synthesized in the granular tubule cells of the submandibular gland. These cells are much more numerous in the male gland.In contrast to -NGF, neither the concentrations of and subunits nor their cellular localization in the mouse submandibular gland have been established. In this study, radioimmunoassays specific for . and subunits determined that both are present in much higher concentrations in the male gland. Immunocytochemical work localized both subunits in the granular tubule cell in the male and female submandibular gland. This indicates that all the components of 7S-NGF exist in a single cell type in the gland and suggests that 7S-NGF can be formed within this cell and secreted as a complex into the saliva.     

Calpain-PKC Inter-Relations in Mouse Hippocampus: A Biochemical Approach

In previous studies, we isolated and identified a -calpain/PKC complex from rabbit skeletal muscle. Here, we have used specific purification procedures in order to study the interactions between -calpain and PKC in mouse hippocampus, a brain structure implicated in memory processes. We observed that -calpain and conventional PKCs (, II and ) are co-eluted after anion exchange chromatography. In contrast to our previous results obtained on skeletal muscle, -calpain and PKC isoenzymes were dissociated after gel filtration chromatography. Furthermore, -calpain induced the proteolytic conversion of PKC, II, and into PKM, II, and with a preferential hydrolysis of PKC, a specific isoenzyme of the nervous system. Although the -calpain/PKC interactions in the hippocampus are quite different from skeletal muscle, our results however, point out the functional importance of these inter-relations. Moreover, as PKC has been involved in the biochemical events underlying learning and memory, the preferential relationship between -calpain and PKC promotes the importance of the role that -calpain could play in the cellular mechanisms of memory formation.     

Cowdria Ruminantium Antibodies in Acaricide-Treated and Untreated Cattle Exposed to Amblyomma Variegatum Ticks in The Gambia

An indirect enzyme-linked immunosorbent assay (ELISA), based on the major antigenic protein 1 fragment B (MAP1-B) of Cowdria ruminantium, was used to assess seroprevalence in cattle in The Gambia. Two groups of 20 N'Dama and 20 Gobra zebu cattle were monitored for 12 months with flumethrin treatment and for another 10 months without acaricidal treatment. Two groups of 20 N'Dama and 20 Gobra cattle served as untreated controls. During the period of acaricidal treatment, the cumulative proportions of positive serum samples were 25.6±5.6% (±confidence interval) and 34.7±6.8% in treated N'Dama and Gobra cattle respectively; the proportion of positive sera in untreated cattle was 52.2±6.9% in N'Damas and 61.4±7.3% in Gobras. Within breed, difference in antibody prevalence between treated and untreated cattle was significant (P<0.001) but between breed differences were not significant. In the 10 months following suspension of acaricide application, there was an increase of proportion of positive serum samples in previously treated N'Dama and Gobra cattle. In both previously treated and untreated animals the peak of positive seroreactions occurred during and subsequent to the period of activity of Amblyomma variegatum adults. Cumulative seroprevalences in previously treated N'Dama and Gobra cattle were 32.6±6.9% and 44.7±8.5%, respectively; in untreated animals seroprevalence was 38.6±7.2% in N'Dama and 65.3±8.4% in Gobra cattle. Throughout the study period, within the N'Dama breed, the seropositive rate in previously treated cattle did not differ from that in untreated animals. Conversely, within the Gobra breed, the number of positive seroreactions was higher (P<0.002) in untreated animals than in previously treated cattle. These results provide a support for designing A. variegatum and heartwater control strategies, if necessary, in The Gambia in relation to cattle breeds.     

Effect of giving insulin and adrenalin alternately on changes in the level of blood glucose in chickens of different breeds

Summary Differences in reaction to exogenous insulin and adrenalin were studied among chickens of Leghorn, White Rock and Rhode Island Red breeds, using level of blood glucose as indicator of the reaction to hormones. It was found that: 1.) The physiological quantity of glucose in blood in chickens of the three breeds ranged from 157 to 194 mg %. 2.) The reaction of chickens to insulin and adrenalin given alternately, measured by changes of blood glucose, differed according to the breed. The smallest reaction to hormones was in Leghorn, the biggest in White Rock. 3.) The chickens of Leghorn and Rhode Island Red breeds, as well as Leghorn and White Rock breeds, differed significantly in maximal glucose level after adrenalin, 4.) The correlation between the normal quantity of blood glucose and the body weight of birds appeared highly significant in cockerels of all three races combined.