中国蝼蛄菌属的研究

本文报道寄生于我国非洲蝼蛄(Gryllotalpa africana Palisot de Beauvois)上的蝼蛄菌属(Tettigomyces)11个种,其中新种1个:线状蝼蛄菌(T.filiformis Ye);国内新记录种10个:渐尖蝼蛄菌(T.acuminatus Thaxt.),非洲蝼蛄菌(T.africanus Thaxt.),短蝼蛄菌(T.brevis Thaxt.),毛生蝼蛄菌(T.chaetophilus Thaxt.),混淆蝼蛄菌(T.co-nfusus Thaxt.),蝼蛄菌(T.gryllotalpae Thaxt.),印度蝼蛄菌(T.indicus Thaxt.),间型蝼蛄菌(T.intermedius Thaxt.),翅生蝼蛄菌(T.pterophilus Thaxt.),普通蝼蛄菌(T.vulgaris Thaxt.)。本文所研究的全部标本都保存于广东省微生物研究所。     

我国的“非洲蝼蛄”应为“东方蝼蛄”

<正> 最早报道我国有非洲蝼蛄Gryllotalpa af-ricana Palisot的是原苏联昆虫学家Bey-Bien-ko,他研究了采自我国东北及兴安岭地区的蝼蛄标本,鉴定为非洲蝼蛄G.africana Pali-sot。我国学者徐荫祺(Hsu Yin-chi)也报道了我国北平和江苏等地有非洲蝼蛄的分     

我国三种蝼蛄的雄性生殖器鉴别

本文记述 3种蝼蛄 (单刺蝼蛄GryllotalpaunispinaSaussure,东方蝼蛄G .orientalisBurmeister及河南蝼蛄G .henanaCaietNiu)的雄生殖器     

齿缘刺猎蝽成虫触角和跗节感器的扫描电镜观察

利用扫描电镜观察了齿缘刺猎蝽(Sclomina erinacea Stal)成虫触角及前足跗节上的感受器,结果表明:齿缘刺猎蝽触角5节,由柄节、梗节和3个鞭节构成,梗节最短;雌、雄虫前足跗节均为3节。触角上共有3种感器,分别为毛形感器、刺形感器和锥形感器,其中,毛形感器、锥形感器各有两种类型,刺形感器有3种类型。雌、雄个体间触角感器类型及分布未见明显差异。前足跗节上仅存在刺形感器,该感器在雄虫前足跗节上的分布较雌虫密集。     

云南草坪中东方蝼蛄的空间分布型

在云南省思茅市体育场,通过实地调查和统计分析后发现东方蝼蛄Gryllotalpa burmeister Burmeister是草坪的重要害虫之一,主要危害草坪草和种子。应用多个聚集度指标和Iwao回归分析法对东方蝼蛄的分布格局进行研究,结果表明,东方蝼蛄在土壤中呈聚集分布,分布的基本单位是个体群。     

非洲雏鸵鸟消化管的组织学观察

为了给非洲鸵鸟(Struthio camelus)雏鸟的饲养管理、生理机能研究和疾病防治提供可靠的形态学依据,采用石蜡切片技术,对6羽50日龄非洲鸵鸟雏鸟消化管的组织学结构进行了观察。结果显示,其消化管具有一般的4层结构。食管有粗大的皱襞,肌层发达,有发达的食管腺;无嗉囊;腺胃的腺体由位于固有膜的单管状腺和位于黏膜下层发达的复管状腺组成;肌胃的黏膜肌层较明显,由内纵肌和外环肌组成;小肠绒毛较长,有分支现象,未见中央乳糜管结构;十二指肠的固有膜中有发达的腺体和集合淋巴小结,黏膜下层内无十二指肠腺;从十二指肠到回肠,肠绒毛的汇合及分支现象更加明显,固有膜内集合淋巴小结的数量逐渐减少,并且空肠的绒毛弯曲呈“S”型;具有一对发达的盲肠;结肠异常发达,黏膜上皮为复层柱状上皮,其间夹有杯状细胞,有黏膜皱襞,绒毛短且发达。非洲鸵鸟雏鸟消化管的特点可能与其食性有关,这决定了非洲鸵鸟具有较强的消化吸收能力。     

非洲钝缘蜱感染Q热立克次体敏感度的测定

Q热立克次体以10^-1—10^-12不同稀释度,用血腔注射法感染非洲钝缘蜱,感染35天,取蜱血淋巴液,分别用Gimenez染色法及免疫荧光技术检查,在10^-1—10^-5的稀释度,两种方法检出率基本相似。10^-6以下各组,免疫荧光尚可检出少数阳性标本,而Gimcnez法则无阳性,前者总阳性率为48.28%,后者为40.68%。感染的蜱悬液接种豚鼠,12组动物血清做Q热补体结合试验全部阳性。动物发病情况如潜伏期长短、发烧天数等似与蜱内立克次体的含量有关。     

黑水虻消化道形态及组织结构的观察

本文比较了不同发育阶段黑水虻Hermetia illucens消化道的形态学差异,掌握了幼虫消化系统的组织学特征。利用体视镜观察黑水虻5龄幼虫、预蛹及成虫的消化道形态,利用光学显微镜和扫描电镜观察幼虫消化道各段(前肠、中肠、后肠)的显微及超微结构。结果表明：黑水虻幼虫及预蛹的消化道均由前肠(食道和前胃)、中肠及后肠组成,从幼虫到成虫,消化道的长度不断缩短。与幼虫和预蛹相比,成虫消化道形态变化明显,前胃消失,出现了嗉囊及胃盲囊,中肠进一步缩短,后肠分化为回肠、结肠和直肠。组织学观察结果显示,幼虫的唾液腺开口于口腔,由膨大的管状腺体和腺管组成。食道由特化为角质刺突的内膜层及发达的肌层组成,其末端延伸至前胃。前胃膨大为球状,包括三层组织结构。根据上皮细胞形态的差异,中肠可分为四个区段。后肠薄,肠腔内褶丰富,肠壁可见数量较多的杆状细菌。马氏管开口于中、后肠交界处,包括4支盲管,管内壁密布微绒毛。黑水虻消化道形态随发育阶段的变化,反映了各阶段摄食及消化生理的差异。幼虫消化道各段具有各自典型的组织学特征,其前、中、后肠可能分别承担了食物接纳与初步消化、消化与吸收以及重吸收功能。本研究结果为进一步了...     

齿缘刺猎蝽生活史及其生物学特性

齿缘刺猎蝽是国内广泛分布的一种捕食性天敌昆虫,能捕食多种农林业害虫。为了充分利用该虫,我们对齿缘刺猎蝽的生活史、形态特征和行为进行了研究。结果表明,齿缘刺猎蝽在湖南一年发生一代,以成虫越冬;5月份产卵,若虫4龄,初孵若虫黄褐色,2-4龄若虫由黄绿色到淡绿色,4龄若虫可见明显白色翅芽,8月份羽化为成虫,成虫灰褐色。各龄若虫和成虫体表均分布有较多棘或刺。成虫平均寿命长达312.5 d,不太活跃,有一定的飞行能力,取食和交配的时间较长,整个产卵期产卵量为每头雌虫35-41粒。     

消化道组织块黏液细胞的组织化学染色

目的：探索中华蟾蜍、黑斑蛙消化道组织块黏液细胞的组织化学染色。方法：利用阿辛蓝-过碘酸Schiff（AB-PAS）反应,对消化道组织块黏液细胞进行染色和观察。结果：对消化道壁较薄的组织块（食管、小肠、大肠）,采用3％乙酸3min、1％阿尔新蓝30min、3％乙酸3min、3％过碘酸氧化10min、Schiff反应20min染色,即可达到良好染色效果;对消化道壁较厚的组织块（胃）,则应采用3％乙酸9min、1％阿尔新蓝70min、3％乙酸9min、3％过碘酸氧化30min、Schiff反应60min染色,将能达到良好染色效果。结论：经过染色可将黏液细胞分为四个类型：Ⅰ型红色,PAS染色阳性,AB染色阴性;Ⅱ型蓝色,PAS染色阴性,AB染色阳性;Ⅲ型紫红色,PAS染色强阳性,AB染色弱阳性;Ⅳ型蓝紫色,PAS染色弱阳性,AB染色强阳性。     

巴西彩龟与无蹼壁虎消化道银染观察

为了探索爬行动物消化道内分泌细胞的分布规律和分泌类型,以改良龙桂开银染法对巴西彩龟、无蹼壁虎消化道嗜银细胞进行了观察,结果表明两种动物从食管到大肠都有嗜银细胞的分布,均在胃幽门或十二指肠有突出的分布密度高峰,在小肠末段或大肠始段有次分布密度高峰,巴西彩龟在食管还有第3分布密度高峰;嗜银细胞多数为毛笔头样、高脚杯状、锥体形、长梭形、椭圆形、不规则形等,多数嗜银细胞可见有明显的突起伸向管腔方向和向管腔释放分泌颗粒的现象,少数可见有伸向基膜或其周围的突起和向基膜或其周围释放分泌颗粒现象,这提示消化道内分泌细胞有闭合型和开放型两种,但更多的是开放型.     

濒危物种绒毛皂荚组织培养快繁技术的初步研究

以绒毛皂荚(Gleditsia vestita Chun et How ex B.G.Li)种子为外植体,通过愈伤组织诱导、不定芽分化增殖、生根和驯化移栽,建立了绒毛皂荚组织培养的快速繁殖体系。结果表明:1)绒毛皂荚子叶和胚轴在MS+6-BA3.0 mg/L+KT 0.4 mg/L+IAA 0.3 mg/L培养基上同步诱导出愈伤和芽,愈伤组织诱导率达到90.5%,同步分化率高达77.9%;2)不定芽增殖的最佳培养基为1/2MS+6-BA 1.0 mg/L+IBA 0.3 mg/L+NAA 0.2 mg/L,培养20 d后,增殖倍数为4.0;3)MS+NAA 0.5 mg/L+IAA 0.25 mg/L条件下,生根率高达100%,且移栽后植株长势好,成活率达90%以上。     

银杏种实发育过程中中种皮的解剖与超微结构观察

观测银杏品种‘佛指’种实中种皮的解剖和超微结构变化的结果表明,银杏种实的单粒重、纵径和横径的增长都呈单S形生长曲线,纵径和横径增长高峰早于单粒重;银杏种实单粒重主要的增长时期与中种皮的木质化进程基本上一致;银杏种实中种皮发育过程中,细胞发生核浓缩、染色质趋边化以及核最终解体等形态学上的变化,呈现细胞编程性死亡特征。     

Antagonistic effects of Streptomyces violaceusniger strain G10 on Fusarium oxysporum f.sp. cubense race 4: Indirect evidence for the role of antibiosis in the antagonistic process

Fusarium oxysporum f.sp. cubense is the causal pathogen of wilt disease of banana. A cost-effective measure of control for this disease is still not available. Streptomyces violaceusniger strain G10 acts as an antifungal agent antagonistic towards many different phytopathogenic fungi, including different pathogenic races of the Fusarium wilt pathogen. In an attempt to understand the mode of action of this antagonist in nature, the interaction between S. violaceusniger strain G10 and F. oxysporum f.sp. cubense was first studied by paired incubation on agar plates. Evidence for the in vitro antibiosis of strain G10 was demonstrated by inhibition zones in the “cross-plug” assay plates. Microscopic observations showed lysis of hyphal ends in the inhibited fungal colonies. Culture of strain G10 in liquid media produces antifungal metabolites, which showed in vitro antagonistic effects against F. oxysporum f.sp. cubense such as swelling, distortion and excessive branching of hyphae, and inhibition of spore germination. An indirect method was used to show that antibiosis is one of the mechanisms of antagonism by which strain G10 acts against F. oxysporun f.sp. cubense in soil. This study suggests the potential of developing strain G10 for the biological control of Fusarium wilt disease of banana. Journal of Industrial Microbiology & Biotechnology (2002) 28, 303–310 DOI: 10.1038/sj/jim/7000247 Received 08 August 2001/ Accepted in revised form 16 February 2002     

The Effects of Social Structure, Geographical Structure, and Population Size on the Evolution of Mitochondrial DNA: II. Molecular Clocks and the Lineage Sorting Period

Evolutionary geneticists have increasingly used sequence variation in mitochondrial DNA (mtDNA) as a source of historical information. However, conclusions based on these data remain tentative because a sufficiently clear understanding of the evolutionary dynamics of mtDNA has yet to be developed. In this paper we present the results of computer simulations designed to illustrate the effects of social structure, geographical structure, and population size on the rate of nucleotide substitution and lineage sorting of mtDNA. The model is based in part on the social structure of macaque monkeys. Simulated populations of females were divided into 25 social groups; the animals in each were distributed in a hierarchy of four dominance rank categories. The probabilities for offspring survivorship were varied among dominance ranks to reflect the fitness consequences of social structure. Population size was varied across runs from 100 to 300 females. The pattern of female migration was also varied to mimic either the island model or the stepping-stone model. All these variables are shown to affect the lineage sorting period (LSP), and certain combinations of parameter values can cause the retention of mtDNA polymorphisms for a very long time. In addition, the simulations exhibited a negative relationship between the LSP and substitution rate over a modest and realistic range of LSP values. An important implication of these results is that estimates of time since isolation based on the assumption of a constant molecular clock may be biased and unreliable.     

Primary structure of the elongation factor G from Escherichia coli. IX. Structure of peptides generated by cyanogen bromide cleavage of the G-factor isolated on thiol-activated sepharose and of the products of the G-factor cleavage at Asp-Pro bonds. Complete primary structure

The amino acid sequence of cysteine- and cystine-containing peptides resulting from cleavage of the G-factor by cyanogen bromide has been determined. For structure analysis cyanogen bromide peptides were further degradated using trypsin, chymotrypsin, thermolysin, staphylococcal glutamic protease, or limited acid hydrolysis. The products of the G-factor cleavage at Asp-Pro bonds were also studied. The obtained data together with those published earlier permitted to establish the complete primary structure of the elongation factor G. The polypeptide chain consists of 701 amino acid residues and has molecular mass of 77321,46.     

Some comments on the article: 'The Structure of Human-Plasma Low-Density Lipoprotein B. An X-Ray Small-Angle Scattering Study' by K. Muller, P. Laggner, O. Glatter, and G. Kostner [Eur. J. Biochem. 82, 73--90 (1978)].

In their paper, K. Muller, P. Laggner, O. Glatter and G. Kostner report X-ray scattering and density experiments on human plasma low-density lipoprotein B, performed at different solvent densities (i.e. contrast variation method). The interpretation of the experimental data lead those authors to question the use of that method and particularly the use of the characteristic scattering functions in the study of serum lipoproteins. In the present paper it is shown that several aspects of their analysis are in fact highly questionable and that the objections raised are therefore unfounded.