Puromycin analogs: action of adrenocorticotropic hormone and the role of glycogen

The effect of the injection into rats of analogs of puromycin, 6-dimethylaminopurine, and the aminonucleoside of puromycin on the stimullation of steroidogenesis by adrenocorticotropic hormone was coin pared with that of puromycin and cycloheximide. This stimulation was blocked only by the antibiotics, which also inhibited adrenal protein synthesis. Glycogenolysis is not associated with the primary mechanism of the adrenocorticotropic hormone stimnulation of steroid hormone biosynthesis in rats.     

Isolated adrenal cortex cells: hypersensitivity to adrenocorticotropic hormone after hypophysectomy

Cells from the adrenals of hypophysectomized rats (up to 28 days after operation) require less adrenocorticotropic hormone to induce one-half maximal rate of production of 3',5'-adenosine monophosphate than do cells from the adrenals of intact rats. A corresponding increase in sensitivity is reflected in the steroidogenic response to adrenocorticotropic hormone up to 2 days after hypophysectomy.     

ACTH肌注建立鸡免疫抑制模型及其评价

连续7 d给鸡肌肉注射不同剂量(15、30、45 IU·kg-1·d-1)的ACTH(adrenocorticotropic hormone)后,通过生理学和免疫学指标对该模型进行了评价。结果显示,45 IU·kg-1·d-1处理组的血清皮质酮浓度、肾上腺指数均显著高于对照组(P<0.05);而血清IgG、IgA、IL-2、IFN-γ水平,胸腺、脾脏和法氏囊指数,组织IgG和禽β-防御素6生成量均显著低于对照组(P<0.05);处理组的血糖值仅在注射ACTH后2 h显著高于对照组(P<0.05),其他时间差异不显著。本研究表明,15、30、45 IU·kg-1·d-1的ACTH连续7 d肌肉注射可引起鸡应激性免疫抑制。血清皮质酮升高、肾上腺肥大和肾上腺皮质细胞增生肥大可用于评价持续应激,而血糖不适合评价持续应激;免疫抑制评价指标包括免疫器官萎缩,组织中免疫细胞数量、IgG和禽β-防御素6生成量下降,以及血清IgG、IgA、IFN-γ和IL-2水平降低。     

Inhibition of adrenocorticotropic hormone secretion in the rat by immunoneutralization of corticotropin-releasing factor

Intravenous administration of rabbit antiserum to ovine corticotropin-releasing factor (CRF) markedly reduced the CRF-induced rise of plasma adrenocorticotropic hormone (ACTH) in intact nonstressed adult male rats while blocking more than 75 percent of the ACTH release observed in rats exposed to ether stress. Furthermore, antiserum to CRF significantly lowered ACTH levels in adrenalectomized animals. These results suggest that endogenous CRF plays a physiological role in regulating ACTH secretion.     

Radioreceptor assay of adrenocorticotropic hormone: new approach to assay of polypeptide hormones in plasma

Biologically active iodine-125-labeled adrenocorticotropic hormone (ACTH) binds specifically to ACTH receptors extracted from adrenals. Unlabeled ACTH at 1 picogram per milliliter significantly displaces labeled ACTH from these receptors. This system, which appears to be applicable to all polypeptide hormones, provides a rapid and sensitive method for measurements of biologically active ACTH in dilute whole plasma.     

Isolated adrenal cells: adrenocorticotropic hormone, calcium, steroidogenesis, and cyclic adenosine monophosphate

Corticosterone production by isolated adrenal cells in response to adrenocorticotropic hormone is reduced when the cells are incubated in a medium that contains no calcium. This reduction is associated with an equal reduction of accumulation of cyclic adenosine monophosphate. Production of corticosterone and accumulation of cyclic adenosine monophosphate are increased when the calcium concentration in the medium is increased (from zero to 7.65 millimolar). This is in contrast to the situation in "subcellular membrane fragments" of adrenal tissue where high calcium in the medium (> 1.0 millimolar) inhibits cyclic adenosine monophosphate accumulation. We propose that adenyl cyclase in the intact plasma membrane is located in a compartment wherein calcium concentration is low and remains unaffected by the concentration of calcium in the extracellular space. It is proposed that, as the concentration of calcium in the incubation medium is increased from zero to 7.65 millimolar, the strength of the signal generated by the interaction of adrenocorticotropic hormone with its receptor and transmitted to the adenyl cyclase compartment is proportionately increased.     

Adenosine 3',5'-monophosphate, adrenocorticotropic hormone, and adrenocortical cytosol protein synthesis

In cultures of mouse adrenocortical tumor cells (Sato's minimal deviation Y-1 clonal strain), the acceleration of steroid biosynthesis after exposure to adrenocorticotropic hormone or cyclic adenosine 3',5'-monophosphate is maximum within 15 to 60 minutes and precedes any significant increase in labeling of protein with [4,5-(3)H]leucine. However, when cytosol proteins are separated by acrylamidegel electrophoresis, rapid changes in the amount and labeling of several protein fractions are evident in less than 30 minutes and are no longer evident within 60 minutes. This finding supports the proposal that the effects of tropic hormones and their intracellular mediators involve rapid selective effects on protein synthesis.     

Normalizing effect of an adrenocorticotropic hormone (4-9) analog ORG 2766 on disturbed social behavior in rats

Short-term isolation increased the frequency of social interactions in rats tested in pairs, while pairs of rats placed in an unfamiliar test cage and subjected to a high level of illumination spent less time in active social contact. These changes in social behavior elicited by environmental manipulations were counteracted by treatment with the adrenocorticotropic hormone (4-9) analog ORG 2766. The peptide's normalizing effect may be mediated by endogenous opioid systems.     

Viral preparations for protection of farm cultures

This paper presents the assessment of the biological effectiveness of viral preparations Fermovirin CpGV for apple protection from the codling moth and Fermovirin HA for protection of tomatoes, maize, and soy from the bollworm. The effectiveness of these insecticides is shown to depend on weather conditions in the vegetation period.     

气田集输管网优化运行方案

选取管网节点参数、压缩机站流量、进气和排气压力作为优化变量,建立了基于压缩机站能耗之和最小的气田管网优化运行数学模型。由于该优化模型具有目标函数和约束条件非线性、求解域非凸性和优化变量非连续性等特点,利用遗传算法的搜索机制和混沌搜索的遍历性,构造了一种新的演化算法用于该模型的求解。以苏里格气田管网为例,使用该方法求解得到最优的管网节点运行参数、压缩机站运行参数及启用台数,在顺利完成天然气输送任务的同时,降低了压缩机站能耗。     

云南气候条件下选育水稻光温敏不育系的策略探讨

 云南光温敏雄性不育水稻的研究和利用虽已经历了较长的时期,但在不育系的选育和制种上一直未取得较大的突破。在新世纪到来之际,为促进云南“两系”杂交稻的育种工作的快速发展,本文结合云南气候的光温特点及云南水稻光温敏不育系选育和利用的经验,对今后云南水稻光温敏不育系的选育、利用的策略进行了探讨。云南纬度低,海拔差异大,日可照时数变化较小,在云南进行温敏不育系的选育和利用具有十分有利的气候条件。其主要的技术路线是利用海拔差异筛选温敏不育系和在不同海拔进行繁殖制种;在选育中运用花药培养技术,缩短温敏不育系的选育周期。     

Atmospheric Lifetime of CHF2Br, a Proposed Substitute for Halons

The rate coefficients, k(1), for the reaction of OH with CHF(2)Br have been measured using pulsed photolysis and discharge flow techniques at temperatures (T) between 233 and 432 K to be k(1), = (7.4 +/- 1.6) x 10(-13) exp[-(1300 +/- 100)/T] cubic centimeters per molecule per second. The ultraviolet absorption cross sections, sigma, of this molecule between 190 and 280 nanometers were measured at 296 K. The k(1), and sigma values were used in a one-dimensional model to obtain an atmospheric lifetime of approximately 7 years for CHF(2)Br. This lifetime is shorter by approximately factors of 10 and 2 than those for CF(3)Br and CF(2)ClBr, respectively. The ozone depletion potentials of the three compounds will reflect these lifetimes.