Potent interaction between glucocorticoids and growth hormone-releasing factor in vivo

Administration of dexamethasone significantly enhanced the pituitary growth hormone response to growth hormone-releasing factor in intact as well as adrenalectomized rats. Thus the inhibitory effects of glucocorticosteroids on somatic growth which involve an interaction of these steroids and growth hormone at a peripheral level may also involve a modification of pathways within the central nervous system that regulate normal growth hormone secretion.     

Patterns of growth hormone-releasing factor and somatostatin secretion into the hypophysial-portal circulation of the rat

The interrelation between the secretion of two hypophysiotropic peptides, growth hormone-releasing factor (GRF) and somatostatin (SRIF), in the generation of episodic growth hormone (GH) secretion was inferred from direct measurements of immunoreactive GRF and immunoreactive SRIF concentrations in the hypophysial-portal plasma of the rat. Secretion of immunoreactive GRF was found to be episodic, with maximal concentrations present during periods of expected GH secretory episodes. Secretion of immunoreactive GRF was accompanied by a moderate reduction in portal plasma levels of immunoreactive SRIF. Passive immunoneutralization of SRIF was associated with increased concentrations of immunoreactive GRF in hypophysial-portal plasma. On the basis of these observations, it appears that each GH secretory episode is initiated by pulsatile secretion of immunoreactive GRF into the portal circulation, which is preceded by or is concurrent with a moderate reduction of inhibitory tone provided by portal immunoreactive SRIF. These experiments provide direct insights into central and adenohypophysial mechanisms by which GRF and SRIF interact to generate episodic secretion of GH.     

江苏省不同生育类型水稻品种对黑条矮缩病的抗感差异性

采用方差分析、多重比较以及t测验等统计方法,对2008-2009年2年江苏省中间试验7个试验组别所有参试品种的黑条矮缩病穴发病率数据进行统计分析,初步明确:不同生育类型水稻品种对水稻黑条矮缩病的抗感差异极显著,但没有发现高抗黑条矮缩病的水稻品种(或类型);不同生育类型水稻品种其黑条矮缩病穴发病率由高到低的顺序为杂交中粳＞迟熟中粳＞中熟中粳＞杂交籼稻＞中熟中粳迟播＞中晚粳＞早熟晚粳;杂交籼(粳)稻和常规粳稻对水稻黑条矮缩病的抗感差异不显著;早、中熟生育类型水稻品种(即8月30日前抽穗)的黑条矮缩病穴发病率明显高于晚熟生育类型水稻品种(即8月30日后抽穗);8月20日前抽穗和8月25日左右抽穗的水稻品种是水稻黑条矮缩病高发病的品种类型,是防治重点;中熟中粳稻品种如果推迟其播种期,其黑条矮缩病穴发病率明显降低.     

16个水稻品种对水稻矮缩病毒抗性的鉴定

16个水稻品种对水稻矮缩病毒(Rice dwarfvirus,RDV)的抗性鉴定结果表明:不同水稻品种对RDV的抗性存在明显差异.根据各品种的发病率划分其抗性等级.免疫品种1个,占供试品种的6.25%;中抗品种6个,占37.50%;中感品种3个,占18.75%;高感品种6个,占37.50%.感病品种潜育期较短,为11-15 d左右;抗病品种潜育期较长,为15-20 d左右.水稻品种的发病率与叶蝉带毒率密切相关,相关系数为99.99%.协优46兼具抗虫性和抗病性;宜香2292仅具抗病性;冈优734为免疫品种,是水稻矮缩病抗性育种的良好材料.     

玉米粗缩病抗性遗传和育种研究进展

系统介绍了玉米粗缩病的病原、寄主、传播方式、危害症状、抗性鉴定方法以及抗性育种现状等,指出利用玉米种质资源的遗传抗性选育抗病品种,才是彻底解决玉米粗缩病危害的根本途径,并对今后的研究方向进行了展望。     

Induction of mating behavior in rats by luteinizing hormone-releasing factor

Ovariectomized female rats treated with estrogen, in dosages too low to provoke mating, displayed this behavior when given subcutaneous injections of synthetic luteinizing hormone-releasing factor (LRF) 48 hours later. Two hours after the injection of LRF, components of female sexual behavior appeared. The lordosis reflex followed mounting by the male, and darting and hopping behavior was quite prevalent. On the other hand, treatment with estrogen followed by luteinizing hormone, follicle-stimulating hormone, or thyrotropin-releasing factor did not induce copulatory behavior. The results suggest that LRF may play a role in induction of mating behavior.     

Growth hormone-releasing factor: direct effects on growth hormone, glucose, and behavior via the brain

Intracerebroventricular administration of human pancreatic growth hormone-releasing factor caused a dose-dependent inhibition of growth hormone secretion, elevated plasma glucose concentrations, and produced marked behavioral and motor effects. Immunoneutralization with antiserum to somatostatin did not reverse the suppression of growth hormone. These findings suggest that hypothalamic growth hormone-releasing factor may regulate its own neurosecretion through an "ultrashort-loop" negative feedback mechanism and may have important neurotransmitter and neuromodulatory functions in the brain.     

The growth factor progranulin binds to TNF receptors and is therapeutic against inflammatory arthritis in mice

The growth factor progranulin (PGRN) has been implicated in embryonic development, tissue repair, tumorigenesis, and inflammation, but its receptors remain unidentified. We report that PGRN bound directly to tumor necrosis factor receptors (TNFRs) and disturbed the TNFα-TNFR interaction. PGRN-deficient mice were susceptible to collagen-induced arthritis, and administration of PGRN reversed inflammatory arthritis. Atsttrin, an engineered protein composed of three PGRN fragments, exhibited selective TNFR binding. PGRN and Atsttrin prevented inflammation in multiple arthritis mouse models and inhibited TNFα-activated intracellular signaling. Collectively, these findings demonstrate that PGRN is a ligand of TNFR, an antagonist of TNFα signaling, and plays a critical role in the pathogenesis of inflammatory arthritis in mice. They also suggest new potential therapeutic interventions for various TNFα-mediated pathologies and conditions, including rheumatoid arthritis.     

Luteinizing hormone-releasing factor potentiates lordosis behavior in hypophysectomized ovariectomized female rats

Subcutaneous injection of luteinizing hormone-releasing factor (LRF) in estrogen-primed hypophysectomized, ovariectomized female rats facilitates the appearance of the lordosis response. The LRF effect on lordosis was seen 90, 180, and 360 minutes after injection. This effect could help to synchronize the female's mating behavior with the ovulatory discharge of luteinizing hormone.     

玉米抗矮花叶病基因的染色体定位及分子标记研究进展

综述了玉米抗矮花叶病基因染色体定位及分子标记的研究进展，并对RFLP，RAPD，SSR，AFLP等几种主要的分子标记在玉米遗传育种中的应用及发展前景作了初步探讨。     

江苏水稻主栽和候选品种抗黑条矮缩病鉴定

[目的]筛选抗黑条矮缩病水稻品种,为抗水稻黑条矮缩病育种提供抗源.[方法]对36份1980~2000年江苏省主栽粳稻品种,57份2001~2008年江苏省主栽粳稻品种,228份2009年江苏省预试、区试粳稻材料,210份珍汕97B/明恢63家系材料及365份连云港市农业科学院新育成稳定粳稻品系进行黑条矮缩病田间自然诱发鉴定.[结果]参试的896份水稻品种(系)中未发现对黑条矮缩病免疫的品种,其中中感以上的品种占81.1%,抗性品种仅占1.8%.不同年份育成的粳稻品种抗性存在差异,近10年育成的抗性强于10年前.连云港市农业科学院近期育成的稳定粳稻品系中,中抗和中感类型所占比例明显高于其他4个群体.在2009年江苏省中试粳稻材料中,中熟中粳类型的发病轻于其他类型.对连云港市水稻条纹叶枯病和水稻黑条矮缩病的关系进行分析,发现水稻黑条矮缩病的发生与抗条纹叶枯病品种的推广种植有一定关系.[结论]获得光身粳等16个抗性较好的水稻黑条矮缩病抗源,可供抗黑条矮缩病育种和抗性机制研究及抗性基因发掘上使用.建议今后江苏省水稻育种中同时兼顾抗条纹叶枯和黑条矮缩病选育.     

Rat transforming growth factor type 1: structure and relation to epidermal growth factor

The complete amino acid sequence of rat transforming growth factor type 1 has been determined. This growth factor, obtained from retrovirus-transformed fibroblasts, is structurally and functionally related to mouse epidermal growth factor and human urogastrone. Production of this polypeptide by various neoplastic cells might contribute to the continued expression of the transformed phenotype.     

抗、感玉米粗缩病材料对灰飞虱的趋性及生存力影响的研究

通过网棚内人工接种1叶1心至11叶1心期的3份抗玉米粗缩病自交系材料(DB544、沈137、90110)和3份感粗缩病玉米自交系材料(掖107、掖478、5003),调查其发病率,明确了抗病材料7叶前的抗病性与7叶后一致,感病材料7叶后的抗病性比7叶前要强;由此认为,玉米苗期为研究抗、感玉米粗缩病材料对灰飞虱的趋性及生存力影响的适宜时期。进而研究了相同环境条件下,网箱或网罩内灰飞虱在抗、感玉米材料上的落虫数和灰飞虱在上述6份材料上饲养死亡50%的时间。结果显示:灰飞虱对抗、感玉米粗缩病材料的趋性以及灰飞虱在抗病材料和感病材料上的生存力差异均不显著,认为玉米对粗缩病的抗性不是通过抗传毒介体灰飞虱而实现的。     

玉米不同品种(品系)对粗缩病的抗性鉴定

2008—2010年对普通玉米、甜玉米、糯玉米及自交系进行了抗粗缩病鉴定试验。结果表明,不同年份和不同品种间抗性存在显著差异。2010年在济宁、温岭和东阳等地各安排30个品种试验,结果表明,品种间抗性存在显著差异,同一品种在不同地区间抗性也存在差异,不同玉米类型对粗缩病抗性无显著差异。综合结果表明,甜玉米品种‘农甜3号’对玉米粗缩病表现较强耐病性。     

19个水稻雄性不育系对南方水稻黑条矮缩病的抗性评价

【目的】评价水稻雄性不育系对南方水稻黑条矮缩病的抗性,为选配抗南方水稻黑条矮缩病的杂交稻组合提供材料。【方法】以19份水稻雄性不育系为材料,采用田间调查自然发病率结合分子检测的方法,评价其对南方水稻黑条矮缩病的抗性。【结果】鉴定出高抗不育系1份,为13s;中抗不育系3份,为分别1s、8s、14s;中感不育系4份,分别为17s、19s、15s、6s;感病不育系10份,分别为18s、3s、9s、12s、11s、4s、16s、5s、7s、2s;高感不育系1份,为10s;未发现对南方水稻黑条矮缩病免疫的材料。【结论】供试的水稻雄性不育系对南方水稻黑条矮缩病普遍表现为抗病性不强,但品种间差异显著,其中13s、1s、14s、8s具有较强的抗病性,是抗病育种中可以利用的资源。     

"Pure" human hematopoietic progenitors: permissive action of basic fibroblast growth factor

Methodology has been developed that enables virtually complete purification and abundant recovery of early hematopoietic progenitors from normal human adult peripheral blood. A fraction of the pure progenitors is multipotent (generates mixed colonies) and exhibits self-renewal capacity (gives rise to blast cell colonies). This methodology provides a fundamental tool for basic and clinical studies on hematopoiesis. Optimal in vitro cloning of virtually pure progenitors requires not only the stimulatory effect of interleukin-3, granulocyte-macrophage colony-stimulating factor, and erythropoietin, but also the permissive action of basic fibroblast growth factor. These findings suggest a regulatory role for this growth factor in early hematopoiesis.