NO对植物生长发育的调控机制

一氧化氮(NO)是具有生物活性和信号转导作用的易扩散分子,它不仅对植物的许多生命活动如种子萌发、叶片扩展、根系生长、逆境生理以及细胞的程序性死亡等具有直接的生理调节功能,而且作为防御反应中的关键信使．参与了植物对外界环境胁迫的应答。近期研究表明,NO与激素在调节植物的生理活动与信号转导方面有明显的协同作用,通过激素起作用可能是植物内源NO作用的机理之一。本文主要通过对NO的产生及其对生理活动的调节机制和在代谢中的信号转导作用等方面来阐述NO在植物生长发育中的作用。     

30%己乙水剂对玉米根系伤流液及其组分的影响

以玉米3138为材料,在大田和PVC管栽条件下研究了应用植物生长调节剂30％己乙水剂对玉米根系伤流量、伤流中无机离子流量、氨基酸组分及流量、激素流量等的影响,结果表明：30％己乙水剂可提高玉米根系伤流量,特别是大喇叭口期和籽粒形成期;提高了伤流中K,P,Ca,Mg,Si,Zn,Mn,Fe,B,Mo,Cu等无机元素流量,氨基酸总流量提高,主要的运输形式氨基酸Ser,Clu,Lys．Arg,Val,Ala,Leu,I1e,His,Try,Phe流量均明显增加,非蛋白质氨基酸GAba大幅度增加,伤流液中IAA在籽粒形成和灌浆期提高,授粉后伤流中Gas提高,CTKs在籽粒形成期提高,ABA在灌浆期提高,吐丝前低于对照。表明30％已乙水剂可促进根系吸收和合成物质向地上部分的输送,对促进地上部发育有重要作用。     

Role of keratinocyte‐derived factors involved in regulating the proliferation and differentiation of mammalian epidermal melanocytes

Melanocytes characterized by the activities of tyrosinase, tyrosinase‐related protein (TRP)‐1 and TRP‐2 as well as by melanosomes and dendrites are located mainly in the epidermis, dermis and hair bulb of the mammalian skin. Melanocytes differentiate from melanoblasts, undifferentiated precursors, derived from embryonic neural crest cells. Because hair bulb melanocytes are derived from epidermal melanoblasts and melanocytes, the mechanism of the regulation of the proliferation and differentiation of epidermal melanocytes should be clarified. The regulation by the tissue environment, especially by keratinocytes is indispensable in addition to the regulation by genetic factors in melanocytes. Recent advances in the techniques of tissue culture and biochemistry have enabled us to clarify factors derived from keratinocytes. Alpha‐melanocyte‐stimulating hormone, adrenocorticotrophic hormone, basic fibroblast growth factor, nerve growth factor, endothelins, granulocyte‐macrophage colony‐stimulating factor, steel factor, leukemia inhibitory factor and hepatocyte growth factor have been suggested to be the keratinocyte‐derived factors and to regulate the proliferation and/or differentiation of mammalian epidermal melanocytes. Numerous factors may be produced in and released from keratinocytes and be involved in regulating the proliferation and differentiation of mammalian epidermal melanocytes through receptor‐mediated signaling pathways.     

The digestive tract of Helicoradomenia (Solenogastres, Mollusca), aplacophoran molluscs from the hydrothermal vents of the East Pacific Rise

Abstract. Species of Helicoradomenia are constantly found at hydrothermal vent sites of the eastern and western Pacific Ocean. The digestive tract of 2 species of the genus was investigated with special focus on the ultrastructure and histochemistry of epithelia and glandular organs. The preoral cavity and foregut epithelia are composed of microvillous main cells, secretory cells producing protein-rich substances, and sensory cells with specialized cilia. The foregut bears a pair of glands with 3 types of extremely long-necked glandular cells surrounded by musculature. Each glandular cell opens directly into the radula pocket without a gland duct. The large radula apparatus consists of pairs of denticulated bars resting on a flexible radular membrane without elaboration of a subradular membrane. The midgut has a narrow, mid-dorsal tract of ciliary cells, but most of the epithelium is composed of digestive cells with a highly developed lysosomal system. The hindgut is lined by ciliated cells and free of glands. The foregut and radula seem to be highly efficient in the capture of relatively large, motile prey. Food contents within the midgut lumen and within some of the large secondary lysosomes indicate a triploblastic metazoan prey of non-cnidarian origin. The digestive tract is not adapted to microvory and there is no indication of a symbiosis with chemoautotrophic bacteria.     

生长激素mRNA在蓝太阳鱼垂体外组织中的表达分布

应用半定量RT PCR方法和Southern杂交技术,系统地研究了生长激素(GH)基因在蓝太阳鱼垂体外组织中的表达情况。在建立检测蓝太阳鱼GHmRNA表达的半定量RT PCR扩增条件之后,分别对蓝太阳鱼雄性幼鱼(6月龄)和雄性成鱼(1年龄)的12个组织部位中GHmRNA的表达进行了检测。结果表明,除了在垂体之外,还在肌肉、性腺、鳃、心脏、脑、肾脏6个组织检测到GHmRNA的表达,但各组织间的表达水平存在差异,而在脾脏、肝脏、胃3个组织未检测到表达;肌肉组织中的表达水平从幼鱼到成鱼后明显提高,同时观察到在幼鱼和成鱼的性腺组织中存在着较高水平的表达。本研究表明,GH基因在蓝太阳鱼的垂体外组织中存在着广泛的表达,由此提示,蓝太阳鱼GH可能以旁分泌或自分泌的方式对其生长繁殖起着重要的作用。     

Serum catecholamine and hormonal titers in the hibernating snake Naja haje haje, with reference to the annual climatic cycle

(1) The analysis of catecholamines revealed alterations in norepinephrine levels in the blood serum and the central nervous system of the Egyptian cobra during the different phases of the hibernation cycle. This may reflect an increased central demand for norepinephrine as a mediator for adaptive changes to cold.

(2) The low and variable concentration of dopamine suggests retarded synthesis during all the phases studied.

(3) Serotonin may be depleted or associated with increased activity of serotonergic neurons during cold acclimation. This increases the rate of turnover of serotonin to 5-hydroxy indole acetic acid.

(4) Cricannual measurements of cortisol and adrenocorticotrophic hormones revealed marked suppression that would clarify the direct effect of hibernation on higher centers. The decreased levels during prehibernation and hibernation were restored in normothermic animals when the pituitary–adrenal axis resumed its activity.

(5) The decline in thyroid hormone concentrations has its behavioural and physiological responses that lead to seasonal adjustments in the hibernating cobras.

新疆塔里木马鹿粪便激素含量季节性变化的初步研究

目的:检测雄性塔里木马鹿的睾酮,雌鹿的雌二醇、雌三醇、孕酮等粪便激素含量,并比较不同月份之间的变化。方法:利用放射免疫分析法(RIA)在且末和尉犁县马鹿场采集塔里木马鹿粪便,检测了2004年2～12月间塔里木马鹿粪便中的激素水平。结果:粪便性激素水平有明显的季节变化(P<0.05)。雄鹿粪便睾酮水平月间差异显著(P<0.05),浓度在8月有2个高峰。雌鹿粪便雌二醇在3月和6月有2个高峰;粪便孕酮水平在3月有2个高峰,在8月有1个高峰;雌三醇差异不显著,但4月的最高值也显著高于其他各时间点(P<0.05)。结论:利用动物粪便研究激素具有对保护动物完全无伤害、材料收集容易等优点,并且有助于评估动物青春期的健康状况、判断动物排卵方式、早孕检查、产前预测等,因而是目前研究野生珍稀动物性激素的一种较为理想的方法。     

Modular genetic control of innate behaviors

Many complex behaviors are genetically hardwired. Based on previous findings on genetic control of mating and other behaviors in invertebrate and mammalian systems, I suggest that genetic control of complex behaviors is modular: first, dedicated genes specify different behavioral patterns; secondly, separable genetic networks govern distinct behavioral components. I speculate that modular genetic encoding of complex behaviors may in part reflect modularity in brain development and function. Editor's suggested further reading in BioEssays From songs to synapses: Molecular mechanisms of birdsong memory Abstract