Ultrastructure of cerebrospinal fluid-contacting neurons immunoreactive to vasoactive intestinal peptide and properties of the blood-brain barrier in the lateral septal organ of the duck

Immuno-electron-microscopic investigations of cerebrospinal fluid (CSF)-contacting neurons immunoreactive to vasoactive intestinal peptide in the duck lateral septum have revealed that this cell type gives rise to an adventricular dendrite terminating with a bulbous swelling in the lateral ventricle. The swelling bears a cilium and contains mitochondria and immunolabeled dense-core vesicles. Two types of processes emerge from the basal part of the perikaryon. The first has a large diameter, contains diffusely distributed immunoreaction, and receives synaptic input, indicating that this process is a basal dendrite. The other type is of a beaded appearance, displays immunolabeled dense-core vesicles, and represents the axon of the CSF-contacting neuron. VIP-immunoreactive terminal formations are located within the neuropil of the lateral septum and the nucleus accumbens. Some of them form synaptic contacts with immunonegative profiles. No VIP-immunoreactive terminal formations are seen in the perivascular spaces of the lateral septum. Tracer experiments with horseradish peroxidase have revealed that the blood-brain barrier is lacking in the lateral septal organ and nucleus accumbens of the duck. Capillaries, arterioles, and venoles of this region are coated by nonfenestrated endothelial cells connected by leaky junctions, allowing the tracer to penetrate from the lumen into the perivascular space and further into the intercellular clefts of the neuropil. Our immuno-electron-microscopic investigations show that VIP-immunoreactive CSF-contacting neurons of the lateral septum closely resemble CSF-contacting neurons occurring in other brain regions, e.g., the hypothalamus. The arrangement of VIP-immunoreactive terminal formations suggests that, in the lateral septum, the VIP-like neuropeptide serves as a neurotransmitter (-modulator). The lack of a blood-brain barrier in the lateral septal organ and the nucleus accumbens raises the possibility that this region is a window in the avian brain allowing exchange of information between the central nervous system and the bloodstream; it thus resembles a circumventricular organ.     

家鸭台湾鸟龙线虫生活史和流行病学的研究

寄生于家鸭台湾鸟龙线虫(Avioserpens taiwana(sugimoto,1919),隶于龙线科(Dracunculidae),首先是杉本正笃(sugimoto,1914)在我国台湾从家鸭和番鸭(Cairina moschata)下颔的柔软组织中发现,检得雌虫作简短的记载,至1919年定名为台湾丝状线     

Calcium and ionophore A23187 stimulates deposition of extracellular matrix and acetylcholinesterase release in cultured myotubes

Summary Calcium (Ca²⁺) and calcium-transporting ionophores stimulate protein secretion in many cellular systems. We demonstrate here that increases in intracellular calcium concentration induce a time- and concentration-dependent deposition of extracellular matrix and an increase in acetylcholinesterase secretion. Scanning and transmission electron-microscopy revealed that treatment with the calcium ionophore A23187, or high extracellular Ca²⁺ levels (5 mM to 15 mM) produce significant deposits of extracellular matrix around the myotubes, as well as a marked increase in the acetylcholinesterase reaction-product. Blocking muscle contraction was not necessary for the induction of AChE secretory activity. Sucrose density-gradients of media conditioned by muscle cells revealed 3 separate acetylcholinesterase molecular forms. However, incubation with A23187 increased only the 4.5 S and the 7.2 S molecular forms, whereas the 12.0 S form showed no significant differences from controls. Polyacrylamide gel electrophoresis, and autoradiography using [³H]diisopropyl fluorophosphate revealed a broad band at 65000 daltons. This band was broader than for controls when medium was obtained from A23187-treated cells. Our results show that increasing intracellular Ca²⁺ concentration induces marked deposition of extracellular matrix and increased acetylcholinesterase secretion, with an apparent selectivity for the monomeric and dimeric acetylcholinesterase molecular forms.     

Structure and protein composition of sites of papillary muscle attachment to chordae tendineae in avian hearts

Summary Most cardiac myocytes transmit force across fasciae adherentes, specialized sites of cell-cell adhesion. However, some cardiac myocytes in papillary muscle terminate on collagenous connective tissue in the chordae tendineae. These papillary myotendinous junctions (MTJs) are specialized for force transmission from myocytes to extracellular matrix. In the present study, we compared structural molecules at papillary MTJs to those at fasciae adherentes and skeletal MTJs. By using indirect immunofluorescence, we found that papillary MTJs more closely resemble skeletal MTJs in their molecular composition in that they are enriched in talin, vinculin, integrin, and fibronectin. Zeugmatin and -actinin, both components of fasciae adherentes, are absent from papillary MTJs. Although papillary MTJs and skeletal MTJs display strong similarities in structural protein composition, ultrastructural organization of the two junctions is different. Papillary MTJs display little folding of the junctional membrane and, according to morphological criteria, more closely resemble sites of thin filament-membrane association in smooth muscle than skeletal MTJs. Thus, papillary MTJs display a combination of structural characteristics described previously in skeletal and smooth muscles but exhibit few structural features observed previously in cardiac fasciae adherentes.     

Cytoskeletal changes accompanying ACTH-induced steroidogenesis in cultured embryonic adrenal gland cells from the Pekin duck

Summary Cells derived from the adrenal glands of duck embryos immediately prior to hatching were grown in culture and used to study the morphological and cytoskeletal changes and steroidogenic responses induced by 1–24 ACTH. Changes in the cytoskeletal components were observed by rhodamine-phalloidin staining for actin and by staining the tubulin immunoreactive components with FITC. The cultures were comprised of a small population of chromaffin cells and a larger population of steroidogenic cells. The chromaffin cells were distinguished by their tyrosine hydroxylase immunoreactivity. The steroidogenic cells were characterized by the presence of sudanophilic lipid droplets, numerous mitochondria, abundant smooth endoplasmic reticulum, microtubules distributed as a fairly even network throughout the cytoplasm, and microfilaments that formed an extensive and elaborate system of stress fibers with many parallel arrays. The cells readily responded to stimulation with ACTH by releasing corticosterone, aldosterone and deoxycorticosterone. Stimulation with ACTH also induced changes in both the cell morphology and the cytoskeleton. Exposure of the cells to Krebs-Henseleit buffer containing 1–24 ACTH caused them to form numerous fine filopodia, to lose their stress fibers, and to form a thick ring of actin at the periphery of the cell. In addition, many cells became extremely arborized with many long branched dendritic processes. The morphological changes appeared to be related to a redistribution of the actin components, and may be explained only in part by the rounding up or retraction of the cytoplasm. The results strongly suggest an involvement of the actin components of the cytoskeleton in the steroidogenic response to corticotropic stimulation.     

Fine structural studies on the thyroid gland of the normal domestic fowl

Summary The ultrastructure of the thyroid gland of the domestic fowl has been investigated and found to be similar to that of mammals. The differences were found at subcellular level in the distribution of the dark bodies which were mainly apical and in the sizes of primary lysosomes. These were found to range from 100 to 500 nm in diameter. All organelles described in mammals as being concerned with the production of thyroglobulin and the two hormones thyroxine and triiodothyronine were found to be present.     

Learning of colour and position cues in domestic chicks: Males are better at position,females at colour

Male and female chicks were trained to discriminate between two boxes for food reinforcement. The correct box was indicated by a colour cue (red or brown) and a position cue (right or left). After learning, the colour and the position cues were dissociated: the right-left location of the two boxes was alternated between trials according to a semi-random sequence.The chicks were thus retrained to discriminate either on the basis of colour (irrespective of position) or on the basis of position (irrespective of colour). There were no sex differences, during training, with both position and colour cues. However, during re-training females performed better on the colour learning task and males performed better on the position learning task.     

The commercial and agricultural applications of animal transgenesis

The potential for commercial application of transgenic technologies in domestic animals is discussed in relation to the areas where a significant impact on agriculture might be expected. These are the endocrine system, novel biochemical pathways, structural proteins of milk and of textile fibers, and the immune system. Manipulation of the endocrine system has been investigated for some years and it is clear that very accurate control is needed over gene expression if this approach is to prove commercially useful. The area most advanced in commercial application is the production of high-value pharmaceutical proteins in the mammary glands of domestic animals. Other applications that are discussed remain to be proven in larger animals despite being demonstrated laboratory test animals. These include a functional cysteine biosynthetic pathway and a functional glyoxylate cycle transferred from bacteria to mice, and alterations to the proteins of hair that change the physical properties of the resultant fibers. Research is also actively directed toward novel approaches for providing domestic animals with resistance to insects.     

塔里木兔和家兔的消化酶活性比较研究

为比较塔里木兔(Lepus yarcandensis)和家兔（Oryctolagus curiculus）消化能力的差异,探索塔里木兔对野外生存环境的食物的适应机制,以家兔为对照,测定了塔里木兔和家兔的胰腺及肠道的消化酶—淀粉酶（碘-淀粉比色法）、纤维素酶（3,5-二硝基水杨酸法）、脂肪酶（比浊法）及胰蛋白酶（紫外线吸收法）的活性。用 SPSS 15.0 软件对实验数据进行统计学分析。结果表明：1）塔里木兔肠道的淀粉酶活性明显高于家兔。其中,塔里木兔十二指肠、空肠及回肠的淀粉酶活性极显著高于家兔（P ＜ 0.01）。淀粉酶活性在塔里木兔和家兔空肠最高。2）塔里木兔肠道的纤维素酶活性高于家兔。其中,塔里木兔盲肠的纤维素酶活性极显著高于家兔（P ＜ 0.01）,其回肠的纤维素酶活性显著高于家兔（P ＜ 0.05）。纤维素酶活性在塔里木兔和家兔盲肠最高。3）家兔胰腺和肠道的脂肪酶活性明显高于塔里木兔。其中,家兔胰腺、十二指肠、空肠及回肠的脂肪酶活性显著高于塔里木兔（P ＜ 0.05）。与消化道相比,脂肪酶活性在家兔和塔里木兔胰腺最高,肠道中空肠的脂肪酶活性最高。4）家兔胰腺和肠道的胰蛋白酶活性高于塔里木兔。其中,家兔空肠和十二指肠的胰蛋白酶活性显著高于塔里木兔（P ＜ 0.05）。胰蛋白酶活性在家兔和塔里木兔空肠最高。可见,与家兔相比,塔里木兔对淀粉类、纤维类物质有较强的消化能力,对脂肪类的消化能力较弱。其中,淀粉酶活性和纤维素酶活性升高,脂肪酶活性和胰蛋白酶活性降低。这可能是塔里木兔适应贫瘠、匮乏的食物环境的重要原因之一。     

Changes in import of non-human primates after ratification of CITES (Washington Convention) in Japan

The total yearly imports of exotic primates into Japan and the countries of origin from 1971 to 1984 were examined. The species, numbers, originating countries, and end-uses of the monkeys imported from 1981 to 1984 were also investigated. After a high plateau of imports which continued until 1980, the total numbers of monkeys imported into Japan were reduced by half from the pre-1980 level of 7,000–8,000/year to a level of 3,000–4,000/year. This drastic decrease appeared to reflect the effect of the Washington Convention ratified in 1980. The majority of species imported wereMacaca fascicularis of Southeast Asian origin, followed bySaimiri sciureus of South American origin. Indonesian and MalaysianM. fascicularis represented the major species in the decrease in monkey imports. However, imports from the Philippines have conversely increased since 1980. Imports ofS. sciureus andCallithrix from South America have remained almost unchanged. These data imply a trend in which experimental monkeys have changed from macaques to smaller New World monkeys.