白腹锦鸡机体营养成分的分析与探讨

本文报道笼养和野生白腹锦鸡机体营养成分及其差异。分析表明,笼养的比野生种营养成分含量高的有:腿肌蛋白质高11％,胸肌、腿肌、全血的氨基酸分别高2.64％,1.39％和4.68％,胸肌、腿肌和肝脏的碳水化合物分别高0.076％、0.092％和3.962％,胸肌和腿肌的维生素A分别高188.63和84.09 I.U.,胸肌和腿肌的维生素D分别高47.2和12.8 I.U.。但是胸肌蛋白质含量笼养的比野生的低26％。     

污水和污水土地处理系统中各种水质对华西蟾蜍蝌蚪红细胞微核率的影响

本文使用蝌蚪红细胞微核率作为指示器研究明通河污水和用污水土地处理系统处理后水质的致突变性。蝌蚪在各种水样品中暴露7天。采心脏血制片。在对照组中,微核率分别为4.40‰和4.68‰。1/4明通河污水组诱发蝌蚪的微核率是17.01‰。同对照组相比有明显的差异。     

红腹锦鸡和白腹锦鸡卵壳的超微结构

本文报道了锦鸡属——白腹锦鸡和红腹锦鸡卵壳的气孔、外壳膜、锥体层、木栅层的超微结构。并对两者的卵壳进行了比较。     

A CD44-like endothelial cell transmembrane glycoprotein (GP116) interacts with extracellular matrix and ankyrin.

We used complementary biochemical and immunological techniques to establish that an endothelial cell transmembrane glycoprotein, GP116, is a CD44-like molecule and binds directly both to extracellular matrix components (e.g., hyaluronic acid) and to ankyrin. The specific characteristics of GP116 are as follows: (i) GP116 can be surface labeled with Na 125I and contains a wheat germ agglutinin-binding site(s), indicating that it has an extracellular domain; (ii) GP116 displays immunological cross-reactivity with a panel of CD44 antibodies, shares some peptide similarity with CD44, and has a similar 52-kDa precursor molecule, indicating that it is a CD44-like molecule; (iii) GP116 displays specific hyaluronic acid-binding properties, indicating that it is a hyaluronic acid receptor; (iv) GP116 can be phosphorylated by endogenous protein kinase C activated by 12-O-tetradecanoylphorbol-13-acetate and by exogenously added protein kinase C; and (v) GP116 and a 20-kDa tryptic polypeptide fragment of GP116 from the intracellular domain are capable of binding the membrane-cytoskeleton linker molecule, ankyrin. Furthermore, phosphorylation of GP116 by protein kinase C significantly enhances GP116 binding to ankyrin. Together, these findings strongly suggest that phosphorylation of the transmembrane glycoprotein GP116 (a CD44-like molecule) by protein kinase C is required for effective GP116-ankyrin interaction during endothelial cell adhesion events.     

电刺激大鼠尾核头部镇痛的中枢效应—[^3H]—2脱氧...

Sokoloff's 2-deoxyglucose (2-DG) autoradiographic technique was used to identify changes of glucose metabolic rate in the rat brain following unilateral stimulation of the head of the caudate nucleus. The results were as follows. The local glucose metabolic rate after noxious stimulation was increased in the somatosensory cortex, cingulate cortex, ventroposterior and parafascicular nucleus of the thalamus, septal area, habenular nucleus, head of caudate nucleus, periaqueductal gray (PAG) and dorsal raphe nucleus (P < 0.05). After stimulating the head of the caudate nucleus, the local glucose metabolic rate of nucleus raphe magnus (rm) and nucleus paragigantocellularis (pgcl) was increased significantly and that of the PAG and dorsal raphe nucleus had a tendency to increase, while stimulation of the head of caudate nucleus could partially abolish the increased glucose metabolic rate in the somatosensory cortex, cingulate cortex, ventroposterior and parafascicular nucleus of the thalamus, septal area and habenular nucleus as induced by noxious stimulation. These results suggest that caudate stimulation is able to depress the activation of some brain structures related to nociception and to activate those related to antinociception. The pgcl, rm, PAG and dorsal raphe nucleus might be the key structures participating in the caudate stimulation produced analgesia.     

Gastric effects of thyrotropin-releasing hormone microinjected into the dorsal vagal nucleus in cats

We investigated the gastric acid secretory and motility responses to microinjection of thyrotropin-releasing hormone (TRH) into the dorsal motor nucleus of the vagus (DMV) in anesthetized cats. Gastric acid output was collected every 15 min through a gastric cannula after saline flush and titrated to pH 7.0. Antral and corpus contractions were continuously recorded by extraluminal force transducers. TRH dissolved in 200 nl of saline and microinjected unilaterally into the DMV induced a dose-dependent (50-200 ng) increase in gastric acid secretion. The acid secretory response began in the first 15 min collection and lasted 45 min. TRH frequently increased the force of contractions of the antrum and corpus within one minute of microinjection. The minimal effective dose for eliciting increased motility was lower than for inducing acid secretion. These results demonstrate that TRH acts in the DMV of cats to stimulate gastric acid secretion and contractions.     

Paracrinology of growth regulation

Embryonic and fetal growth is dependent on genetic factors and epigenetic factors such as peptide growth factors. We describe here the interactions of several peptide growth factors during the growth and function of two cell types, growth plate chondrocytes from the ovine fetus and astroglial cells from the newborn rat cerebral cortex. Isolated chondrocytes released two endogenous growth factors, basic fibroblast growth factor (bFGF) and insulin-like growth factor II (IGF II). Although the latter was released in greater abundance, as detected by radioimmunoassay, exogenous bFGF was more than a thousand fold more active as a mitogen. Insulin was also able to increase chondrocyte replication at physiological concentrations, and bFGF, insulin and IGFs were additive in their effects on DNA and protein synthesis. Transforming growth factor beta (TGF beta), which is abundant in bone, had little effect on chondrocyte DNA or total protein synthesis alone, but blocked the stimulatory actions of insulin and IGFs on these parameters. However, TGF beta when alone or in combination caused an increase in the collagen: non collagenous protein ratio of new proteins synthesized by chondrocytes. Adult rat brain is a rich source of IGF II, and both IGF I and II are present during neurogenesis and gliagenesis in the fetal and neonatal rat respectively. We have cultured astroglial cells isolated from neonatal rat cerebral cortex to examine the production and interaction of peptide growth factors during their growth. Isolated astroglial cells contained mRNAs encoding both IGF I and II but abundance was not regulated by other hormones or growth factors. Using affinity cross-linking we found that cultured cells also released two species of IGF binding protein (IGF-BP) of 33 kDa and 38 kDa. Northern blot analysis using homologous cDNA probes showed that astroglial cells expressed IGF-BP2 and BP3, but little BP1. Both IGF I and II were mitogenic for astroglial cells, as was insulin at physiologic concentrations. Exogenous IGF-BP2 was able to modulate the mitogenic actions of exogenous IGF I. These two very different cell models show many similarities of endogenous growth control. Both release IGFs and IGF-BPs which regulate mitogenic rate. In addition, in both insulin functions as a growth factor at physiologic concentrations. These findings suggest common principles governing embryonic and fetal growth and development. Studies have shown that fetal and neonatal growth is independent of regulation by classic hormones (e.g. growth hormones) synthesized by the mother or the fetus. It is believed that embryonic and fetal growth is controlled by two major mechanisms, namely, (i) the genetic factors as determined by the embryonic and fetal genome, and (ii) the epigenetic and environmental factors that alter the expression of the embryonic or fetal genome.(ABSTRACT TRUNCATED AT 400 WORDS)     

Recombinant human granulocyte macrophage colony-stimulating factor (rhGM-CSF) induces human macrophage production of transforming growth factor-alpha

Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) is known as an inducer of proliferation and functional activation of myeloid cells. This study was carried out to characterize the effect of purified recombinant human GM-CSF (rhGM-CSF) on induction of TGF-alpha in macrophages. Using Northern blot analysis and immunoassays, we show here that rhGM-CSF markedly stimulates production of TGF-alpha messenger RNA and protein in normal tonsil macrophages. The findings are consistent with macrophages being a normal inducible source of TGF-alpha which may be an important mediator of various activities of GM-CSF both in hematopoietic and non-hematopoietic cells.     

Zinc deficiency and the formation of white structures in immature embryo cultures of wheat (Triticum aestivum L.)

The effect of microelements on the induction of embryogenic callus from epiblast and scutellum of wheat (Triticum aestivum L.) embryos was studied by the sequential omission of each of the microelements from Murashige & Skoog medium. Omission of iron caused a marked decrease in yield and poor shoot formation from embryogenic callus. The yield of embryogenic callus on medium without added manganese was also reduced. Omission of boron, copper-cobalt, iodine, and molybdenum had little effect on the induction of embryogenic epiblast callus. By contrast there was a marked increase in the formation of white structures on the medium without any microelements or, specifically without addition of zinc. Since the formation of typical embryoids of wheat is associated with the formation of white structures, our result highlights the importance of certain microelements on somatic embryogenesis of wheat.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - MS medium Murashige & Skoog medium     

Regional differences in retinoid release from embryonic neural tissue detected by an in vitro reporter assay.

Retinoic acid and related retinoids have been suggested to contribute to the pattern of cell differentiation during vertebrate embryonic development. To identify cell groups that release morphogenetically active retinoids, we have developed a reporter assay that makes use of a retinoic acid inducible response element (RARE) to drive lacZ or luciferase reporter genes in stably transfected cell lines. This reporter gene assay allows detection of retinoids released from embryonic tissues over a range equivalent to that induced by femtomole amounts of retinoic acid. We have used this assay first to determine whether the floor plate, a cell group that has polarizing properties in neural tube and limb bud differentiation, is a local source of retinoids within the spinal cord. We have also examined whether the effects of exogenously administered retinoic acid on anteroposterior patterning of cells in the developing central nervous system correlate with differences in retinoid release from anterior and posterior neural tissue. We find that the release of morphogenetically active retinoids from the floor plate is only about 1.5-fold that of the dorsal spinal cord, which does not have neural tube or limb polarizing activity. These results suggest that the spatial distribution of retinoid release from spinal cord tissues differs from that of the neural and limb polarizing activity. This assay has also shown that retinoids are released from the embryonic spinal cord at much greater levels than from the forebrain. This result, together with previous observations that the development of forebrain structures is suppressed by low concentrations of retinoic acid, suggest that the normal development of forebrain structures is dependent on the maintenance of low concentrations of retinoids in anterior regions of the embryonic axis. This assay has also provided initial evidence that other embryonic tissues with polarizing properties in vivo release retinoids in vitro.