凤城六索线虫新种记述：线虫纲：索科

本文报道从辽宁省凤城县的柞树根部土壤中采获的六索属线虫一新种,命名为凤城六索线虫,新种Hexametmis fengchengensis sp.nov.     

中华卵索线虫的研究与应用

中华卵索线虫Ovomermis sinensis Chen etal.作为一种昆虫病原线虫,在农业害虫的生物防治中起着重大作用。文章综述90年代以来我国有关中华卵索线虫的生物学特性、田间应用、体内外培养以及生化与分子生物学研究进展,并对中华卵索线虫今后的研究方向提出建议。     

中华卵索线虫雌雄成虫可溶性蛋白双向电泳分析

昆虫寄生线虫 (又称虫生线虫、昆虫病原线虫)是本世纪发展起来的一种有潜能的生物防治因子 ,它寄主范围广、能主动寻找寄主、对人畜及环境安全无毒。中华卵索线虫是昆虫寄生线虫的一种 ,由我国学者发现并命名的新种 (陈果等 ,1 9 91 ) ,具有广泛的寄主范围 ,可杀灭粘虫 (任慧芳等 ,1 989)、烟青虫、烟蚜 (侯茂林等 ,2 0 0 2 )及棉铃虫 (陈果 ,1 994)等危害十分严重的害虫 ,其寄生率等于宿主的死亡率。因此在生物防治手段日益突出的今天 ,中华卵索线虫无疑有着广泛的应用前景。然而 ,在线虫培养的过程中 ,无论是体内培养还是体外培养 ,我们发…     

中华卵索线虫的性别分化分子机理研究进展

中华卵索线虫Ovomermis sinensis Chen et al.是一种宝贵的昆虫天敌资源,具有特殊的寄生期营养竞争压力决定其雌雄性别分化机制。本文重点概述了近年中华卵索线虫性别决定与分化、寄生期生理生化以及分子系统学研究等方面的进展,并对中华卵索线虫今后的研究方向提出了建议。     

中华卵索线虫的体外培养

在研究中华卵索线虫的体外培养方法的同时,对其在不同培养基中的生长发育情况进行了观察。结果表明：以培养基TC－199加20％热灭活胎牛血清的培养效果较为理想,大多数线虫可存活3个月,最大虫体长55．1mm,宽204．13um,其发育程度大致与该种索线虫在宿主粘虫体内寄生8－9天的情况相近,培养期间观察到2次蜕皮;第一次蜕皮在卵内,第二次在培养6－8天之后,口针消失,虫体内滋养物体发育明显,尾部附器已经形成,没有观察到生殖原基的发育。     

寄生于直翅目昆虫的索线虫属一新种—西安索线虫（线虫纲：索科）

本文报道陕西省西安附近的咸阳市近郊农作区的直翅目昆虫日本菱蝗、姬蟋等体内寄生的索线虫属一新种,命名为西安索线虫Ｍｅｒｍｉｓ ｘｉａｎｅｎｓｉｓ ｓｐ．ｎｏｖ．;指出了它的鉴别特征。索线虫属及直翅目宿主皆为国内新记录。     

中华卵索线虫线粒体基因组多态性分析

为完善昆虫病原索科线虫线粒体基因组全序列数据库, 更系统地研究其基因组特征和系统演化规律, 进而为发挥该线虫生防潜力打下基础, 我们开展了中华卵索线虫Ovomermis sinensis线粒体全基因组的研究。该研究通过线粒体基因组滚环复制及酶切图谱, 揭示了中华卵索线虫线粒体基因组具有种内遗传多态性, 即群体中单体线虫具有独特的酶切条带, 且条带累加之和变化范围较大, 为16.5～24.5 kb。为进一步了解线粒体基因组多态性特征及产生的分子机制, 采用两步长PCR方法对2条代表性成虫线粒体基因组进行了测序及拼接, 得其全长分别为18 864和16 777 bp。对这2条序列的比对表明, 线粒体基因组中位于ND2和ND4之间的可变区域, 不仅基因排列顺序不同, 且存在ND3基因重复现象, 这是导致中华卵索线虫线粒体基因组呈现多态性的主要原因。通过对以上研究结果的分析及与GenBank中已有的6种索科线虫线粒体基因组序列进行比对, 概括出其线粒体基因组基本特点: ①线粒体基因排列顺序各不相同;②部分线虫线粒体基因存在重复现象, 且重复次数不同;③线粒体基因组大小存在很大差异。     

中华卵索线虫感染棉铃虫后脂肪体结构的变化

采用组织超薄切片技术,电镜下观察研究昆虫棉铃虫Helicoverpa armigera Hǖbner脂肪体细胞的超微结构,结果表明。在中华卵索线虫Ovomermis sinensisChen感染棉铃虫后的不同寄生时期内,宿主脂肪体细胞内的线粒体、内质网、脂肪球和细胞核等细胞器在形态和结构上均有较大的病理变化,这些病理变化,与这一时期中华卵索线虫的生长发育和寄生生活等特点密切相关。     

棉铃虫感染中华卵索线虫后血淋巴游离氨基酸含量的变化

中华卵索线虫Ovomermis sinensis感染棉铃虫Helicoverpa armigera 1天后,棉铃虫幼虫血淋巴中游离氨基酸总量大幅度下降,各种游离氨基酸的含量也是如此变化。感染2～4天后的棉铃虫血淋巴中游离氨基酸总量变化不大,各种游离氨基酸的含量有升有降。感染5～6天后的棉铃虫血淋巴中游离氨基酸总量和各种氨基酸的含量都急剧上升。研究表明,中华卵索线虫寄生棉铃虫时,棉铃虫血淋巴中游离氨基酸含量的变化朝着有利于线虫生长发育的方向进行。     

棉铃虫感染中华卵索线虫后血淋巴酚氧化酶活性的变化及其分离纯化

研究了中华卵索线虫Ovomermis sinensis感染棉铃虫Helicoverpa armigera幼虫后宿主体内酚氧化酶活性的变化。研究结果表明,在感染后的第1天,中华卵索线虫的侵入引起酚氧化酶活性的增加,感染组酶活性是同期对照组的1.12倍; 但在随后的寄生期间,中华卵索线虫抑制了宿主的酚氧化酶活性,其中以第5天的抑制最为强烈： 同期对照组酶活性是感染组的1.52倍。对酚氧化酶进行了初步的分离纯化,纯化倍数为41.5倍,酶得率为12.7%,比活力为4 030.6 U/mg。     

MOVEMENT OF EELWORMS.: IV. THE INFLUENCE OF WATER PERCOLATION

A study was made of the relationship between rate of flow of water through sands of different particle size and the downward velocity of eelworms of various lengths and activities. The relationship between rate of flow of water and velocity of eelworms is not linear. For rates of flow less than about 500 cm./hr. the velocity of the eelworms relative to the velocity of water is greater than for flow rates greater than about 500 cm./hr. For rates of flow greater than 500 cm./hr. an equation is derived which relates velocity of eelworms, rate of water flow, length of eelworms and pore diameter in the sand. The following facts were established: the velocity of the eelworms increases as pore diameter increases; the velocity approaches zero when the eelworms' length exceeds four times the pore diameter; the relationship between velocity of eelworm and velocity of water is independent of the eelworms' own activity; the equation of eelworm movement is valid for both continuous and discontinuous saturated flow. With flow rates less than about 500 cm./hr., the velocity of the eelworms increases as the eelworms' activity increases and eelworms appear to pass through smaller pores than at high flow rates. Dead or inactive eelworms do not progress very far in sand even at high flow rates and observations suggest that slight flexing movements of the eelworm body is essential for passage.     

THE LOCOMOTION OF LIMAX : I. TEMPERATURE COEFFICIENT OF PEDAL ACTIVITY.

Pedal progression of the slug Limax maximus was studied to obtain relations between wave velocity on the sole of the foot, wave frequency, the advance due to a single wave, and the velocity of vertically upward creeping. Each of the first three quantities is directly proportional to the simultaneous velocity of progression. Under comparable conditions, that is when work is done at a constant rate, the frequency of pedal waves is influenced by the temperature according to the equation of Arrhenius, with µ = 10,700 (Q ₁₀ for 11° to 21° = 2.1). The velocity of a single wave must have very nearly the same "temperature characteristic," which is found also in another case of nerve net transmission (in Renilla).     

TIME RELATIONS OF GROWTH : I. GENETIC GROWTH CONSTANTS OF ANIMALS.

This paper is the first in a series proposing to evaluate growth constants from the viewpoint of and by the methods of the physical chemist. After discussing the physicochemical conception of growth, tentative numerical values of two growth constants are given for several species of animals including man, and the methods of computation are discussed in detail.     

SOME ASPECTS OF SECRETION : I. SECRETION OF WATER

If we increase the osmotic pressure at one end of a Nitella cell by applying a solution of sucrose and if we subsequently submerge the entire cell in water we find that water enters at the end where the osmotic pressure is higher and comes out of the cell at the other end. If similar inequalities of osmotic pressure should arise as the result of metabolism we can understand how a secreting cell might take up water at one spot on its surface and expel it in another spot and thus bring about the secretion of water. The Nitella cell can expel water from a region of the cell which is in contact with water, air, or mineral oil.     

THE INACTIVATION OF TRYPSIN : IV. THE ADSORPTION OF TRYPSIN BY CHARCOAL.

1. Charcoal removes trypsin from solution. The amount removed depends on the order in which the solutions are mixed. The reaction is not reversible and is almost independent of the pH of the solution. 2. Charcoal which has been previously treated with gelatin does not remove trypsin from solution. 3. The reaction is not analogous either to the reaction between trypsin and the inhibiting substance of serum or to the reaction between solid protein and either pepsin or trypsin.     

THE EFFECT OF RENNIN UPON CASEIN : II. FURTHER CONSIDERATION OF THE PROPERTIES OF PARACASEIN.

The properties of the paracasein and casein preparations studied are compared in Table VI. See PDF for Structure I. Casein retains its characteristic solubility in NaOH: (1) after being exposed to a high degree of alkalinity during its preparation, (2) when recovered from partially hydrolyzed solutions in NaOH, and (3) after being kept for a prolonged time at the isoelectric point at 5°C. II. It follows from I, that: (1) paracasein is not identical to casein modified by an excess of alkali, and that (2) this protein was not produced from casein by a partial hydrolysis of the latter in presence of NaOH.     

AMPHOTERIC BEHAVIOR OF COMPLEX SYSTEMS : II. TITRATION OF SULFANILIC ACID-GLYCINE MIXTURES.

Electrometric titrations of glycine, sulfanilic acid, and various mixtures of the two have been made. These mixtures are shown to give a curve which, between their respective isoelectric points, is different from that of either substance. These mixtures have a maximum buffering power at a pH which can be theoretically calculated, and which has the characteristics of an "isoelectric point of the system." Other pairs of ampholytes are shown to act in an analogous manner.