植物激素的信号转导系统研究进展

植物激素是调节植物生长、发育和抗逆性的重要物质 .蛋白质激酶的磷酸化级联放大系统在激素的信号转导中起重要作用 .乙烯早期信号转导的 ETR1系统类似原核生物的信号转导的双组分系统 .本文综述了有关植物激素的信号转导系统的研究进展 ,并提出了今后研究的思路     

Natural and synthetic allatotoxins: suicide substrates for juvenile hormone biosynthesis

Cytotoxic agents with antijuvenile hormone activity in insects have been discovered. Their mechanism of action may involve an oxidative bioactivation into a reactive quinone methide.     

AP2/EREBP转录因子的结构与功能

AP2/EREBP是植物所特有的一类转录因子。AP2/EREBP家族成员在结构上有共同的特点:每个成员都含有由60个左右氨基酸组成的非常保守的DNA结合域(即AP2/EREBP结合域)。含有AP2/EREBP结合域的转录因子在植物中广泛存在,并且参与植物的生长、发育以及多种生理生化反应的信号转导,如:花器官形成、抗病、抗逆、激素响应(乙烯)等。在此,主要介绍了植物转录因子AP2/EREBP家族的结构及其功能的研究进展。     

Effect of N-methyl-aspartate and Betaine on Growth Performance and Correlation Between Growth Hormone, Growth Performance and Carcass Composition in Finishing Pigs

［1］Etherton T D. Anabolic effects of porcine somatotropin on pig growth in: Designing foods: Animal product options in the marketplace. National Academy Press, Washington, DC. 1988:194 - 202. ［2］XU Z R, et al. Effect of betaine on carcass characteristics and approach to mechanism of the effect in finishing swine. Acta Veterinaria et Zootechnica Sinica, 1998, 29(5) :397 - 405. (in Chinese) ［3］Knight C D, et al. The performance and carcass composition responses of finishing swine to a range of porcine somatotropin doses in a l-week delivery system. J. Anim. Sci. 1991, 69:4678 - 4689. ［4］Zhou S W, et al. Effect of the recombinant porcine somatotropin on weight gain and carcass composition in swine. Journal of Beijing Agricultural University, 1993, 19: 93 97. (in Chinese) ［5］Danghaday W H. Double effect of growth hormone. Nature,1972..235 - 237. ［6］Estienne M J, et al. N-methyl-D, L-aspartate induced growth bermine secretion in barrows: possible mechanisms of action. J.Anim. Sci. 1996, 74:597- 602. ［7］Barb C R, et al. Aspartate and glutamate modulation of growth bormone secretion in the pig: Possible site of action. Domest.Anim. Endocrinols. 1996, 13:81 - 90. ［8］Lindstrom P, et al. Effect of N-methyl-D, L-aspartate on isotated rat somatotrophs. Endocrinology, 1992, 131: 1903 -1907.     

Expression of an exogenous growth hormone gene by transplantable human epidermal cells

Retrovirus-mediated gene transfer was used to introduce a recombinant human growth hormone gene into cultured human keratinocytes. The transduced keratinocytes secreted biologically active growth hormone into the culture medium. When grafted as an epithelial sheet onto athymic mice, these cultured keratinocytes reconstituted an epidermis that was similar in appearance to that resulting from normal cells, but from which human growth hormone could be extracted. Transduced epidermal cells may prove to be a general vehicle for the delivery of gene products by means of grafting.     

Infectious and selectable retrovirus containing an inducible rat growth hormone minigene

A growth hormone minigene carrying its natural promoter (237 nucleotides of chromosomal DNA) was stably propagated in a murine retrovirus containing hypoxanthine-guanine phosphoribosyltransferase as a selectable marker. Glucocorticoid and thyroid hormone inducibility was transferred with the growth hormone gene. Recombinant virus with titers of 10(6) per milliliter was recovered. This demonstration that retroviruses can be used to transfer a nonselectable gene under its own regulatory control enlarges the scope of retroviral vectors as potent tools for gene transfer.     

Thyroid hormone induction of an autocrine growth factor secreted by pituitary tumor cells

Thyroid hormones stimulate the rate of cell division by poorly understood mechanisms. The possibility that thyroid hormones increase cell growth by stimulating secretion of a growth factor was investigated. Thyroid hormones are nearly an absolute requirement for the division of GH4C1 rat pituitary tumor cells plated at low density. Conditioned media from cells grown with or without L-triiodothyronine (T3) were treated with an ion exchange resin to remove T3 and were tested for ability to stimulate the division of GH4C1 cells. Conditioned medium from T3-treated cells was as active as thyroid hormone at promoting GH4C1 cell growth but did not elicit other thyroid hormone responses, induction of growth hormone, and down-regulation of thyrotropin-releasing hormone receptors, as effectively as T3 did. A substance or substances associated with T3-induced growth stimulatory activity migrated at high molecular weight at neutral pH and was different from known growth-promoting hormones induced by T3. The results demonstrate that thyroid hormones stimulate the division of GH4C1 pituitary cells by stimulating the secretion of an autocrine growth factor.     

Prolactin: evidence that it is separate from growth hormone in human blood

A highly sensitive bioassay has been developed for prolactin, which uses a mammalian end organ and which is capable of measuring the hormone in unextracted human plasma. High prolactin activity, largely neutralizable with antiserum to human growth hormone, is stimulated along with high immunoassayable growth hormone by insulin-induced hypoglycemia. High prolactin activity, not neutralizable with antiserum to growth hormone, exists with low concentrations of plasma growth hormone in postpartum patients and patients with galactorrhea.     

生长抑素主动和被动免疫及基因免疫研究进展

生长抑素(somatostatin,SS)是下丘脑释放的14肽激素,在动物体内具有广泛的抑制作用,特别是对生长及免疫反应具有明显的影响,通过耗竭或免疫中和体内的SS水平相应提高生长激素(GH)等水平促进动物生长。文中简要介绍了生长抑素主动和被动免疫的研究进展及基因免疫的作用机理、特点及增强基因免疫的途径;阐述了生长抑素基因疫苗的研究和应用发展前景。     

Amphibian pituitary growth hormone and prolactin: immunochemical relatedness to rat growth hormone

Growth hormone and prolactin were electrophoretically isolated from amphibian pituitaries and then were tested in a radioimmunoassay with labeled rat growth hormone and antiserum to the same hormone. This isolation and purification of the hormones increased the steepness of the slopes of competitive inhibition in this system when compared to those of crude extracts. Both hormones from most species tested showed high immunochemical cross-reactivity, indicating that amphibian growth hormone and prolactin are structurally related to rat growth hormone.     

昆虫保幼激素及其类似物的应用研究进展

介绍了昆虫保幼激素及其类似物应用于杀虫剂和昆虫生长调节剂的研究情况,并展望了昆虫保幼激素及其类似物的应用前景。     

The generation of insulin-like growth factor-1--sensitive cells by growth hormone action

Insulin-like growth factor-1 (IGF-1), a mitogenic polypeptide, is usually considered the sole effector by means of which growth hormone increases tissue mass. However, growth hormone, but not IGF-1, directly promotes the differentiation of cultured preadipocytes to adipocytes. Adipocytes newly differentiated from precursor cells in response to growth hormone were shown to be much more sensitive to the mitogenic effect of IGF-1 than the precursor cells. The result of IGF-1 action is therefore a selective multiplication of young differentiated cells (cloned expansion). This supports the concept of a dual effector system in which the preferred target cells of IGF-1 action are created by the direct action of growth hormone.     

不同栽培架式和生长调节剂对京亚葡萄产量及品质的影响

为了确定适宜的栽培架式和生长调节剂,以京亚葡萄为供试品种,研究不同栽培架式、不同生长调节剂对京亚葡萄产量和品质的影响。结果表明,京亚葡萄比较适宜的架式为单臂篱架;用植物生长调节剂12.5 mg/L GA3+10 mg/L CPPU浸渍,最佳处理时期为全开花后2 d,花后15 d再喷12.5 mg/L GA3,京亚葡萄的果实品质最佳。     

The bST debate: The relationship between awareness and acceptance of technological advances

Despite concerns of consumer protection andenvironmental groups that the use of geneticallyproduced growth hormone in milk-producing cows mayadversely impact the safety of the milk supply,scientific evidence and governmental findings from theUSA appear to indicate that milk fromtreated cows is identical in quality, taste, andnutritional value to milk from untreated cows. Limitedexperience to date in the USA demonstrateslittle consumer resistance to milk from cows that havereceived the growth hormone, which can lead to a 15%increase in milk production. In fact, if there is noperceived differentiation between the two forms ofmilk, the issue offers little choice to consumers atlarge, and may result in economic benefit only toselected dairy farmers, as well as the producers ofthe genetically produced growth hormone. Thissituation in the USA may be an example ofdysfunctional technology transfer, with desirablebenefits to a few, and as yet unknown benefits to thesociety. The USA has taken a bold move inapproving the use of bovine growth hormone in milk-producing cows, while the European Union has takena divergent approach by enacting lengthy moratoriumsagainst its use. The basic lesson to be learned fromthe bST case is that lack of awareness amonggovernment officials and the public at large serves asa significant impediment to the adoption of newtechnologies. Accordingly, delays may occur indelivery of significant social benefits to thepopulation as a whole. Obviously, the issue extendsbeyond bST.     

Receptor-associated resistance to growth hormone-releasing factor in dwarf "little" mice

Anterior pituitaries from the dwarf mouse strain "little" did not release growth hormone or accumulate adenosine 3',5'-monophosphate (cyclic AMP) in response to human and rat growth hormone-releasing factor (GRF). Dibutyryl cyclic AMP, as well as the adenylate cyclase stimulators forskolin and cholera toxin, markedly stimulated growth hormone (GH) release. The basis of the GH deficiency in the little mouse may therefore be a defect in an early stage of GRF-stimulated GH release related either to receptor binding or to the function of the hormone-receptor complex.     

甲基氨基酸对肥育猪生长性能和生长激素本关指标的影响

饲粮中添加50mg/kg N－甲基天冬氨酸（NMA）和1750mg/kg甜菜碱均明显加速了肥育猪生长，改善了胴体组成，并显著提高了肥育猪血清内源性GH和IGF－I水平，相关性分析表明，两种物质引起的内源性GH变化与猪的生长性能与胴体组成及血清尿素氮、游离脂肪酸和脂肪酶，呈现极强相关性（P＜0.01），IGF－I亦呈现相似相关性。由此可见，通过添加这两种物质可以提高血清中内源性GH水平，从而促进了猪生长，改善胴体组成。     

Paradoxical elevation of growth hormone by intraventricular somatostatin: possible ultrashort-loop feedback

Somatostatin, the growth hormone-inhibiting factor, when microinjected into the third ventricle of the rat brain, paradoxically induced the release of growth hormone. A pituitary site of action having been ruled out, this result supports the concept that exogenous somatostatin within the hypothalamus acts either to suppress the release of somatostatin from somatostatin-containing neurons, possibly via an ultrashort-loop feedback mechanism, or to augment release of hypothalamic growth hormone-releasing factor, thereby inducing a release of growth hormone. Injection of somatostatin into the third ventricle also decreased plasma concentrations of luteinizing hormone, follicle-stimulating hormone, and thyroid-stimulating hormone, probably by inhibiting the release of luteinizing hormone-releasing factor and thyrotropin-releasing factor.     

影响刺五加茎尖培养的因素

为探讨用组织培养方法繁一加苗木，以刺五加茎尖为试样，在春、夏、秋和冬季取材，以ＭＳ和Ｗｎｉｔｅ为基本培养基，附加生长素（ＮＡＡ．ＩＡＡ）和细胞分裂素（ＢＡ．ＧＡ、ＫＴ）进行组织培养，结果表明，以春季萌芽前取材最好；Ｗｈｉｔｅ培养基适合于刺五加茎尖的无性系快速繁殖，其适合的激素组成成为为ＢＡ０．５ｍｇ／Ｌ＋ＮＡＡ０．１ｍｇ／Ｌ；培养基附加葡萄糖比附加蔗糖生长快近２０％；较适宜的生根培养基为１／２ＭＳ     

贵州矮马与伊犁马生长激素基因5’侧翼区的结构特征

为了摸索贵州矮马生长发育的调控机制,探明贵州矮马与伊犁马生长激素基因5’侧翼区的结构特征,以4～5龄的贵州矮马和7～8龄的新疆伊犁马为研究对象,采用直接测序法从两种马基因组中克隆了生长激素(GH)基因5’侧翼区的DNA序列,并进行生物信息学分析。结果表明:1)从基因组中克隆的711bp片段为GH基因5’侧翼区序列;2)两个马品种的GH基因5’侧翼区中都存在TATA box、CAATbox、GC box和Octamer位点等真核生物启动子结构;3)从伊犁马GH基因5’侧翼区中检测到1个位于30bp处的突变位点发生了G→C颠换,由此新增了1个转录因子upstream stimulatory factor(USF)结合位点;4)从贵州矮马和伊犁马GH基因的5’侧翼区序列中发现了MZF1、CdxA、Nkx-2、AML-1a和c-Myc等19种共58个转录因子的结合位点。结论:克隆的711bp基因序列中存在大量的转录调控元件。