DNA-dependent synthesis of RNA is not implicated in growth response of chick comb to androgens

Local application of actinomycin D does not detectably modify growth response of the chick comb to androgens. The mode of action of androgens on chick comb (a connective-tissue organ) appears to differ from their action on epithelial-tissue organs such as seminal vesicles and prostate.     

Erythrocyte transfer RNA: change during chick development

Radioactive aminoacyl transfer RNA's isolated from erythrocytes in the blood of 4-day-old chick embryos and from reticulocytes of adult chickens were analyzed by chromatography on methylated albumin kieselguhr and freon columns. Embryonic and adult methionyl transfer RNA's showed qualitative and quantitative differences in both chromatographic systems. The patterns for arginyl, seryl, and tyrosyl transfer RNA's in the two cell types were similar, while the leucyl transfer RNA patterns suggested a difference.     

Lactate dehydrogenase isozymes of chick embryo: response to variations of ambient oxygen tension

Incubation of chick embryos in an hypoxic environment causes an ncrease in the proportion of tissue lactate dehydrogenase (LDH) made up of subunit M, whereas incubation in aerobic conditions decreases the proportional amount of subunit M. The variation of ambient oxygen tension does not change the total LDH activity. These results support the hypothesis that oxygen or oxidative metabolites have an effect on the synthesis of the subunit peptides.     

Embryonic chick intestine in organ culture: response to vitamin D 3 and its metabolites

Embryonic chick intestine maintained in organ culture responded to vitamin D(3) and its metabolites 25-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol by synthesis of calcium-binding protein and enchanced calcium-45 uptake. The dihydroxy metabolite was by far the most potent inducer of the protein and also acted more rapidly than vitamin D(3) to stimulate isotope uptake. Despite its lower potency, vitamin D(3) itself was effective.     

Synthesis of nonribosomal RNA by lymphocytes: a response to phytohemagglutinin treatment

When lymphocytes are stimulated to enlarge and divide by treatment with phytohemagglutinin, most of the rapidly synthesized RNA is nonribosomal. The phenomenon is a response by lymphocytes to stimulation by phytohemagglutinin, rather than a general concomitant of lymphocyte growth.     

Short- and long-lived messenger RNA in embryonic chick lens

Cells of the embryonic chick lens pass through a definite sequence of macromolecular synthesis as they differentiate and migrate from one zone of the organ to another. Auto-radiographic studies of RNA synthesis and protein synthesis show that long-and short-lived messenger RNA's are both present in the lens.     

Conversion of ectoderm to mesoderm by cytoplasmic extrusion in leech embryos

The role of cytoplasmic domains in the determination of the fates of ectodermal and mesodermal cells has been investigated in leech embryos. When yolk-deficient cytoplasm (teloplasm) was extruded from the animal pole of the zygote, the ectodermal precursor blastomere was converted to a mesodermal fate. This change of fate can be prevented by replacement of the extruded animal teloplasm with teloplasm from the vegetal pole. The fate of the mesodermal precursor blastomere was unaffected by teloplasm extrusion or rearrangement. These results demonstrate that ectodermal and mesodermal determination offate involves a binary decision dependent on the position of teloplasm along the animal-vegetal axis.     

Estrogen-dependent increase in transfer RNA during differentiation of the chick oviduct

Estrogenic hormones induce morphologic and biochemical differentiation in the oviduct of the immature chick. Concomitant with the hormone-stimulated tissue growth, there was an increase in 4S RNA, as judged by polyacrylamide-gel electrophoresis, and a corresponding increase in cellular transfer RNA activity, as measured by the amino acid acceptor capacity. This system may be suitable for studying the relation of hormones to transfer RNA in a differentiating tissue.     

两种致病菌对杂交东方鲀非特异性免疫和抗氧化指标影响

为研究迟钝爱德华氏菌和哈氏弧菌感染对杂交东方鲀"冀研一号"(菊黄东方鲀♀×红鳍东方鲀♂)非特异性免疫和抗氧化指标影响,分别对杂交东方鲀腹腔注射PBS、迟钝爱德华氏菌和哈氏弧菌,注射后6、12、18、24和36h分别取肝胰脏,测定其谷胱甘肽(GSH)、谷胱甘肽过氧化物酶(GSH-PX)、总超氧化物歧化酶(T-SOD)、谷草转氨酶(GOT)、谷丙转氨酶(GPT)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)活力。结果表明,在攻毒后36 h内,注射迟钝爱德华氏菌"冀研一号"东方鲀肝胰脏总超氧化物歧化酶、碱性磷酸酶和酸性磷酸酶酶活均极显著升高(P0.01);攻毒后36 h内谷胱甘肽过氧化物酶、谷胱甘肽均表现升高趋势。感染哈氏弧菌后,肝胰脏中谷胱甘肽过氧化物酶、总超氧化物歧化酶活力均高于对照组;谷胱甘肽含量表现升高趋势。试验鱼体感染致病菌后,引起肝胰脏非特异性免疫和抗氧化指标变化。     

Electroencephalographic activation: nonspecific habituation by verbal stimuli

A decrease in the duration of the electroencephalographic activation response to a series of different words: emotional, "neutral," and scrambled occurred. The response to "neutral" words was consistently briefer than that to the other words. This result is evidence of a nonspecific habituation of activation, which implies that habituation to classes of stimuli can occur.     

玉米非编码RNA Zm-1701在逆境胁迫下的表达研究

分别用20%PEG6000,150 mmol·L-1 NaC1,100μmol·L-1 ABA对3叶期的玉米根进行胁迫处理,通过分析3种胁迫应答基因的表达情况确定胁迫的有效时间点,进一步研究玉米非编码RNA Zm-1701在玉米受到干旱和盐胁迫处理时的表达情况.结果表明,玉米根在受到干旱和盐胁迫后,根中非编码RNA Z...     

长链非编码RNA调控植物生长发育与逆境胁迫响应研究进展

长链非编码RNA(long non-coding RNAs,lncRNAs)是一类转录本长度大于200 nt的非编码RNA,其表达和保守性比编码蛋白的mRNA低,在动植物各个生物学过程中发挥重要作用。近年来,植物lncRNAs的作用和功能受到广泛关注。本文总结了lncRNAs调控植物生长发育和生殖,应对低温、干旱等非生物胁迫和病虫害等生物胁迫方面的功能,同时根据lncRNAs在基因组上的来源,分类讨论了不同来源lncRNAs的作用机制,为深入挖掘植物新的lncRNAs、功能验证与作用机制探究提供参考。     

RNA病毒诱导的烟草WRKY转录因子基因的应急表达

植物和病毒在基因水平上的互作是植物感病和抗病的分子基础。以模式植物烟草及其3种RNA病毒（马铃薯Y型病毒,Potato virus Y,PVY;烟草花叶病毒,Tobacco mosaic virus,TMV;黄瓜花叶病,Cucumber mosaic virus,CMV）为试材,旨在研究受病毒共同诱导、并可能在植物抗病反应中具有重要功能的转录因子基因。试验首先获得10个受病毒诱导的烟草同源基因。在比较了3种病毒侵染、低温和盐害协迫以及逆境信号物质(茉莉酸甲酯与水杨酸)处理对上述基因表达的影响后发现, 3种RNA病毒所诱导的植物基因有所不同。但属于WRKY基因家族的06G基因受3种病毒的共同、高效诱导,其表达水平与叶片发育程度呈负相关。研究结果表明, 该基因在植物病毒病发生及植物抗病分子育种中可能有重要意义。     

Galactose toxicity in the chick: hyperosmolality

Galactose-fed chicks have been found to develop severe hyperosmolar dehydration. Although biochemical abnormalities have been observed in the brain of the galactose-toxic chick, the observed physiologic alteration of serum osmolality could be the major factor responsible for the galactose toxicity syndrome in the chick.     

Brain polysomes: response to environmental stimulation

Polysomes have been isolated from rat brain and characterized by their appearance in the electron microscope and by their sedimentation in sucrose density gradients. Rats were isolated for 3 days in the dark and were then returned to the light for 15 minutes. The polysomes in brain, but not in liver, decreased in rats deprived of light and increased in those stimulated with light. These findings together with an increased capacity for protein synthesis in the brain in vitro and in vivo suggest that an increase in the activity of messenger RNA in the brain may result from environmental changes.     

Shark pit organs: response to chemicals

Nerve fibers from pit organs and canal neuromasts are distinguished by the nature of their electrophysiological response to mechanical and chemical stimulation. Pit organs respond to touch but have a relatively high threshold compared with canal neuromasts. They respond readily to sodium and potassium chloride solutions, the rate of discharge increasing with the concentration of the solution. Order of effectiveness with 1 molar solutions of monovalent cations is as follows: potassium, rubidium > sodium, ammonium > cesium, lithium. Anions are ineffective. Divalent cations such as calcium and magnesium are inhibitory. Responses to acid, sugar, and quinine are either very slight or inhibitory.     

Silicon: an essential element for the chick

Silicon is required for normal growth and development in the chick when a low silicon diet is fed in a trace element controlled environment. Day-old deutectomized cockerels fed a purified amino acid diet showed significantly retarded growth and development within 2 to 3 weeks. Chicks fed the same diet plus a silicon supplement showed 50 percent higher growth and normal development. Silicon meets the criteria for an essential trace element.     

Small nuclear RNA U2 is base-paired to heterogeneous nuclear RNA

Eukaryotic cells contain a set of low molecular weight nuclear RNA's. One of the more abundant of these is termed U2 RNA. The possibility that U2 RNA is hydrogen-bonded to complementary sequences in other nuclear RNA's was investigated. Cultured human (HeLa) cells were treated with a psoralen derivative that cross-links RNA chains that are base-paired with one another. High molecular weight heterogeneous nuclear RNA was isolated under denaturing conditions, and the psoralen cross-links were reversed. Electrophoresis of the released RNA and hybridization with a human cloned U2 DNA probe revealed that U2 is hydrogen-bonded to complementary sequences in heterogeneous nuclear RNA in vivo. In contrast, U2 RNA is not base-paired with nucleolar RNA, which contains the precursors of ribosomal RNA. The results suggest that U2 RNA participates in messenger RNA processing in the nucleus.