武汉东湖若干种轮虫休眠卵的形态观察

休眠卵是轮虫在恶劣生态条件下形成的滞育结构。本研究用光学显微镜和扫描电子显微镜对东湖14种轮虫休眠卵形态进行了观察,其中关于尾突臂尾轮虫（Brachionuscaudatus,Barrois＆Daday）、方形臂尾轮虫（Bquadridentatus,hermann）、中型晶囊轮虫（Asplanchnaintermedia,Hudson）、顶生三肢轮虫（Filiniaterminalis,Plate）的休眠卵的形态特征尚未见过报道。这些休眠卵一般卵壳较厚,颜色较深,壳表面有纹饰。不同种轮虫的休眠卵形态、壳饰各不相同,具种的特异性,但在某些轮虫,即使同一种中休眠卵形态有时亦存在较大的差异。     

武汉东湖的轮虫

本文根据1973—1975、1979—1982年在武汉东湖进行的调查资料,并与1962—1963年他人的研究结果对比,总结了20年来,在东湖2个采样站上轮虫的种类演替和数量的变动。轮虫的种类明显地减少。Ⅰ站由1962—1963年的68种至1982年减为44种;Ⅱ站由56种减为49种。由原来Ⅰ站种类多于Ⅱ站演变为Ⅱ站多于Ⅰ站。轮虫的数量急剧增加。Ⅰ站轮虫的年平均值由1962—1963年的687个/升至1982年上升为3,555个/升;Ⅱ站由332个/升上升为1,538个/升。轮虫总数的变动曲线呈夏季和秋季二个高峰,冬、春季轮虫的数量均很低。本文从生态学的角度,对轮虫种类演替及其数量的发展趋势进行了探讨。     

HETEROGENEITY OF HISTAMINE Hi-RECEPTORS: SPECIES VARIATIONS IN [3H]MEPYRAMINE BINDING OF BRAIN MEMBRANES

[³H]Mepyramine binds with high affinity to membranes from brain of human, rat, guinea-pig, rabbit and mouse with drug specificity indicating an association with histamine H₁receptors. Considerable species differences occur in the affinity of [³H]mepyramine, with guinea-pig and human having 34 times greater affinity than rat, mouse or rabbit. The greater affinity of [³H]mepyramine in guinea-pig than in rat is attributable both to faster association and slower dissociation rates in guinea-pig. Species differences in affinity for H₁ receptor sites occur for some antihistamines but not for others. Some tricyclic antidepressant and neuroleptic drugs are extremely potent inhibitors of [³H]mepyramine binding, exceeding in potency any H₁ antihistamines examined. The tricyclic antidepressant doxepin and the neuroleptic clozapine are the most potent of all drugs examined in competing for [³H]mepyramine binding. The regional distribution of specific [³H]mepyramine binding differs considerably in the various species examined.     

FINE STRUCTURE OF THE CILIA OF ROTIFERS

The fine structure of the coronal cilia of the rotifer Philodina citrina has been studied in detail. Specimens were fixed with OsO₄ and embedded in butyl—methyl methacrylate, Epon 812, or Vestopal and sectioned with a Porter-Blum microtome. The details of structure of the rootlets, basal bodies, basal plates, and free cilia are described. The general structure of the rotifer ciliary apparatus conforms well to that established for other species. One of the main observations is the difference in structure of the peripheral filaments in the opposing halves of a cross-section of the free cilium. Also, in longitudinal sections evidence is offered for the existence of a helical structure in the peripheral filaments.     

A NEW ASPECT OF CORTICAL DEVELOPMENT IN ROOTS

Heimsch , Charles . (Miami U., Oxford, Ohio.) A new aspect of cortical development in roots. Amer. Jour. Bot. 47(3) : 195—201. Illus. I960.–Excised roots of some tomato varieties exhibit a pronounced increase in diameter of the apex when grown in culture. Anatomical study demonstrated that most diameter growth was attributable to an increase in cell number across the cortex, this having resulted from a progressive increase in the number of periclinal divisions in the innermost cortical cell layer. Although these divisions occur within 200 microns or less of the root apex, their differential distribution during development can be inferred from the cell pattern at mature levels in the basal portion of the tip. Nearly all roots showed an unequal distribution of the last periclinal divisions, there being at some levels more in sectors peripheral to phloem strands than elsewhere. Toward the tip from such levels the sectors of widened cortex were extended around the central cylinder, in some cases around the xylem poles to complete a layer, of newly added cells. The findings are discussed in relation to developmental implications and interpretations and possible causal factors are reviewed.     

VARIATIONS IN THE STRUCTURE OF MITOCHONDRIA

A characteristic internal structure, consisting of a double-layered outer wall enclosing a matrix-filled space through which pass double-layered membranous folds, would appear to comprise as satisfactory a definition of mitochondria for electron microscopy as their intravital affinity for Janus green affords for light microscopy. Relying for identification upon this characteristic internal structure, mitochondria appear to be pleomorphic structures which vary in size, shape, complexity, and density. They are labile also in that their number may increase or decrease under controlled conditions. The possibility therefore exists that these organelles are constantly being formed and destroyed, perhaps by their participation in metabolic processes. The problem of the origin of mitochondria is in an unsatisfactory state. New organelles unquestionably are formed in particular physiological states. The possibility that new bodies are produced by fission of ones already present does not seem adequate. On the other hand, the possible fabrication of new mitochondria out of intracellular membranes, although an attractive hypothesis, has not been adequately substantiated.     

保安湖浮游轮虫的动态研究

保安湖9个采样站1996年轮虫的种类组成、密度和生物量,并与1986-1987和1992-1993年他人的研究结果进行了比较,总结了10年来保安湖轮虫种类演替,密度及生物量的动态变化。并从浮游轮虫的角度探讨草型湖泊的合理开发利用问题。       

水域增温对轮虫影响初探

根据对漳泽水库增温水域的轮虫调查,发现轮虫有33种,平均密度262.5个/1,生物量为0.0631mg/1。并运用相关、回归等方法分析了轮虫的群落特征,结果表明:在20—25℃温度范围内,温度增加,群落多样性指数和均匀度指数也增加;温差越大,群落的种类相似性系数越小;温度对不同种类的轮虫影响不同,两种优势种针簇多肢轮虫(Polyarthra trigla)和沟痕泡轮虫(Pompholyx sulcata)对温度呈现出显著的相关性,其回归方程分别为:Y=362.21-13.99T和Y=-1005.9 49.886T;随着温度增加,优势种从针簇多肢轮虫向沟痕泡轮虫转变。     

THE SIZE OF PORES IN COLLODION MEMBRANES

By the application of Poiseuille''s law to the rate of flow of water through collodion membranes, it is calculated that the membranes used had pore radii of the order of 0.3 to 2 x 10^–6 cm. On the same basis the number of pores per sq. cm. appears to vary from 270 x 10¹⁰ to 7 x 10¹⁰, decreasing with increase in pore size. Reasons are given for preferring these figures for the radii to figures, 100 times as large, which were calculated by others. Microscopic examination of the membranes, with dark-field illumination, indicates that they are made up of solid granules or filaments of collodion much less than 1 x 10^–4 cm. in thickness.     

冷冻取消胼胝体传递对猫皮层17/18区边界细胞部分电生理特性的影响

用IBM-XT微机控制产生各种取向的可移动正弦光栅作为视觉刺激,用金属微电极在猫皮层一侧17/18区边界附近进行胞外记录,神经信号由微机实时采集并进行数据处理;对11只猫的62个细胞进行了冷冻取消另一侧胼胝体向记录侧传递前后细胞的取向选择性,最佳取向和最大反应的测定与比较.发现冷冻后有至少50%细胞的取向选择性强度发生了变化,其中选择性减少与增加的数目基本相等;有20-30%细胞的最佳取向发产了10°至20°的变化;有一半以上细胞的最大反应发生了变化,其中三分之二细胞的反应减少,其余的增加.通过部分细胞的恢复实验证明以上变化基本是可逆的,说明胼胝体对这些特性有一定影响.     

落叶生境蛭态轮虫物种多样性及四种中国新记录种

为研究落叶生境蛭态轮虫物种多样性,对中国8省28个落叶样品进行了调查,采样范围涵盖中国热带、亚热带及温带地区,海拔高度从3m到1500m不等,共记录蛭态轮虫3科8属29种,其中中国新记录属1属,中国新记录种4种,将中国蛭态轮虫记录由88种增加到92种.研究获取了新记录种跛足突盘轮虫(Bradyscela clauda ...     

大脑皮层神经元NMDA受体的单通道特性

本文用膜片箝技术对机械分离培养的大鼠大脑皮层神经元胞体上的ＮＭＤＡ受体的单通道特性进行了研究,实验用细胞贴附和内面向外两种形式记录单离子通道的活动。电极液内含有ＮＭＤＡ或Ｌ－门冬氨酸时,在皮层神经元上常见电导为３５ｐＳ的离子通道。通道对Ｎａ＋,Ｋ＋非选择性通透,对Ｃｌ－不通透,其平均开放时间和开放概率随超极化程度增大而降低。开放、关闭时间及ｂｕｒｓｔ时程的分布直方图均需双指数拟合。Ｍｇ２＋以电压和浓度依赖性的方式减小通道开放时间,ＡＰＶ能阻断通道活动,温度降低使通道开放时间延长及电流幅度减小。本文结果表明大脑皮层神经元上ＮＭＤＡ受体通道活动自身具有电压依赖性,因此提示ＮＭＤＡ受体通道的正常功能活动可能依赖于某些细胞内调控过程的存在。     

THE EQUIVALENCE OF AGE IN ANIMALS

1. A method of plotting growth curves is presented which is considered more useful than the usual method in bringing out a number of important phenomena such as the equivalence of age in different animals, difference in the shape and duration of corresponding growth cycles in different animals, and also in determinating the age of maxima without resorting to complicated mathematical computations. 2. It is suggested that after the third cycle is past the conceptional age of the maximum of the third cycle may be taken as the age of reference for estimating the equivalent physiological ages in different animals. Before the age of the third cycle, the maxima of the second and first cycles are most conveniently used as points of reference. 3. It is shown that the product of the conceptional age of the maximum of the third cycle by 13, gives a value which is, with the possible exception of man, very near to the normal duration of life of animals under the most favorable conditions of life. In other words, the equivalent physiological ages in different animals bear an approximately constant linear relation to the duration of their growth periods. 4. Attention is called to certain differences in the shape and duration of the corresponding growth cycles in different animals and of the effect of sex on these cycles.     

厦门所见若干蚊虫形态的变异

致乏库蚊为热带及亚热带最常见之种,故凡医学及昆虫书籍均有记载,但各家对于本蚊之记述不一。今将我们就所捕蚊虫观察所得综述如下。     

VARIATIONS IN THE NATURAL HISTORY OF PSORIASIS

Latent psoriasis is a state which exists before the development of clinical psoriasis and wherein probably some as yet undiscovered defect exists. Investigation concerning a group of persons with latent psoriasis might disclose basic aberrations.The natural course of psoriasis may be altered by therapy. Folic acid antagonists and intradermal corticosteroids may at times eclipse psoriatic lesions. Oral adrenal corticosteroids may prove morbidistatic but on discontinuance a rebound flare may occur which is both protracted and recalcitrant. Antimalarial agents when employed as therapy for coexistent arthridites may cause psoriasis to become more severe.The Goeckerman regimen which employs topical tar and ultraviolet light therapy produces in some 75 per cent of patients a prolonged remission. As it is safe and repeatable it is favored for the usual severe case of psoriasis.Psoriasis therapy is better assessed by considering its effect on the natural evolution of the disease.