USE OF BLUE LAKE AS AN INDICATOR OF BACTERIAL PENETRATION INTO EGGS

Blue Lake, an insoluble dye, was evaluated as an indicator of potential bacterial penetration into eggs. Various groups of eggs (fresh-laid; commercial; water-washed) were dipped in 0.25% (w/v) Blue Lake in 0.1% Triton X-100 solution for 2 min and incubated at room temperature up to 1 ± 24 h. Penetration was detected by counting the blue dots on shell membranes after breaking the eggs. Commercial eggs allowed the easiest penetration. All commercial eggs showed blue dots even at 2 min incubation and the average count reached 111/egg at 1 h. Water-washed eggs allowed much less penetration than commercial eggs and the counts of blue dots on those eggs were 10/egg at 2 min and 22 at 1 h. Fresh-laid eggs did not allow any penetration up to 24 h. Above results corresponded very well with the penetration study with Salmonella enteritidis and also with the morphological study of eggshell surfaces using electron microscopy where fresh-laid eggs had intact cuticle layers, but commercial eggs did not. Thus, Blue Lake dye might be used as a rapid indicator of bacterial penetration through eggshells.     

黑龙江省三江平原丹顶鹤的数量分布

在地面调查的基础上,我们使用Y-11轻型飞机对黑龙江省三江平原地区的丹顶鹤的数量分布近行了调查,调查时飞行高度80米,航速140公里/小时,续航里程共3748公里。调查结果表明,丹顶鹤在三江平原主要分布在8个地区,其中嘟噜河下游、洪河自然保护区、七星河流域和兴凯湖低地是主要繁殖地,总数量共309只。     

刺激兔迷走神经引起的压抑心室纤颤作用

单个期前刺激引起急性缺血心脏能终止的心室纤颤。电刺激左侧颈迷走神经外周端可以缩短心室纤颤的持续时间。静脉注射β受体阻滞剂心得安后,刺激迷走神经对心室纤颤的作用消失。实验表示增加迷走神经的紧张性可能对终止室颤起有益作用。     

Lipid Metabolism in Fucus serratus as Modified by Environmental Factors

The effect of changes in the environment on lipid metabolismhas been studied in the brown alga, Fucus serratus L. Lightstimulated the incorporation of radioactivity from /{^I4C/}acetateinto oleic and, especially, into linoleic acid. The same effectwas caused by lowering the incubation temperature from 15 °Cto 4 °C. Incubations in the presence of Cd ^{+ +}, Pb ^{+ +} orZn^{+ +} had no effect on the total uptake of /{¹⁴C/}acetate intothe frond tip samples, but lowered the labelling of total lipidsrelative to aqueous-soluble components. However, pre-exposureof the algae to heavy metal cations caused changes in the uptakeof radioactivity but had less effect on the relative labellingof lipids than incubations in the presence of heavy metal cations.Algae collected from sites where the dissolved levels of heavymetals were elevated, showed a decrease in the relative labellingof lipids from /{¹⁴C/}acetate. Concentrations of Cd^{+ +}, Pb⁺⁺ or Zn^{+ +} at 10 x levels found at the collection site had littleeffect on the pattern of fatty acids made by Fucus serratus. Key words: Lipid metabolism, Fucus serratus L., Environmental changes     

麻黄碱抑制小鼠输精管电场刺激致收缩的机制

麻黄碱(10 nmol/L~(-0.1) mmol/L)对电场刺激所致输精管收缩的浓度依赖性抑制作用可被育亨宾(0.1 μmol/L)减弱。去甲肾上腺素(0.1 nmol/L~(-10)μmol/L )和酪胺(0.1 μmol/L~(-0.1) mmol/L)也有类似麻黄碱的作用,去氧肾上腺素则缺乏此种作用。利血平处理和可卡因(10 μmol/L)可减弱麻黄碱和酪胺的抑制效应,但能增敏去甲肾上腺素的作用。高 Ca~( )和4-氨基吡啶(50 μmol/L)明显减弱甚至取消麻黄碱对电场刺激的抑制效应。以上结果提示麻黄碱抑制电场刺激所引起的输精管收缩。至少部分通过促进神经末梢释放去甲肾上腺素间接作用,后者激动突触前α_2-肾上腺素受体,从而抑制去甲肾上腺素的进一步释放。麻黄碱和其释放的去甲肾上腺素的作用,又可能与阻遏 Ca~( )内流有关。     

The Nuclear Envelope of Amoeba proteus During Mitosis as Studied With a Monoclonal Antibody Against a Membrane-Associated Protein

. The behavior of nuclear envelopes during mitosis in Amoeba proteus was studied by means of indirect immunofluo-rescence staining using a monoclonal antibody against a 220-kD membrane-associated protein of amoebae in conjunction with DAPI staining of chromatin. The antibody selectively recognized antigens on nuclear envelopes during interphase but did not react with the nuclear membranes during mitosis until after cytokinesis had been completed. Thus, it appeared that the membrane-associated protein reacting with the monoclonal antibody and normally present on the nuclear membranes was absent from fragmented nuclear membranes or nuclear membranes that were continuous but did not have the honey-comb lamina. The findings suggested that the 220-kD nuclear-membrane protein may be involved in the dissolution and reformation of the honey-comb lamina during mitosis in amoebae.     

小麦颖果果皮绿色层内同化物的合成与分配

小麦幼嫩颖果中,果皮内侧发育出由内表皮与亚表皮组成的一薄层绿色组织。显微与亚显微结构观察表明,虽绿色层只接受到自然光照的1/4～1/8,叶绿体仍能正常发育,叶绿素含量与叶绿体数量均高出旗叶。大量胞间连丝联接相邻的绿色细胞,并在一定时期形成开放的胞间通道,显然有利于同化物的快速胞间运输。离体颖果饲喂~14CO_2试验证明,新合成的同化物从绿色细胞输向胚珠。绿色层产生的同化物可能通过合点端的珠心进入胚乳或通过珠孔直接汇聚到胚珠和分化中的原胚。