The mechanism of the reaction forming tryptophanyl-tRNA, catalyzed by tryptophan:tRNA-ligase

The rates of tryptophanyl-tRNA formation catalyzed by beef pancreas tryptophanyl-tRNA synthetase were measured in a concentration range of each substrate (tryptophan, ATP and yeast tRNATrp) and also in the presence of various concentrations of substrate analogues (tryptamine and alpha,beta-methylene analogue of ATP) concentrations. The data obtained were compared with the kinetic equations which described various possible mechanisms of the reaction. The comparison of the mechanisms was based on the calculation of relative probabilities of each hypothesis the efficiency of which was demonstrated earlier. The calculations have shown that two mechanisms according to which the intermediate enzyme-aminoacyl-adenylate complex formation involves the enzyme-aminoacyl-tRNA complex are the most probable ones.     

The second annual creative talent awards program in psychology.

The program evaluates "dissertations of doctoral candidates on the basis of originality and creativity, indicative of the author's promise of an eminent contribution to the science of psychology." The winners were Karl E. Weick, who received $1000 and Michael I. Posner and David J. Reynolds, who received $500 each. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of nerve growth factor in the development of rat sympathetic neurons in vitro. III. Effect on acetylcholine production

The effect of nerve growth factor (NGF) on the development of cholinergic sympathetic neurons was studied in cultures grown either on monolayers of dissociated rat heart cells or in medium conditioned by them. In the presence of rat heart cells the absolute requirement of neurons for exogenous NGF was partially spared. The ability of heart cells to support neuronal survival was due at least in part to production of a diffusable NGF-like substance into the medium. Although some neurons survived on the heart cell monolayer without added NGF, increased levels of exogenous NGF increased neuronal survival until saturation was achieved at 0.5 microgram/ml 7S NGF. The ability of neurons to produce acetylcholine (ACh) from choline was also dependent on the level of exogenous NGF. In mixed neuron-heart cell cultures, NGF increased both ACh and catecholamine (CA) production per neuron to the same extent; saturation occurred at 1 microgram/ml 7S NGF. As cholinergic neurons developed in culture, they became less dependent on NGF for survival and ACh production, but even in older cultures approximately 40% of the neurons died when NGF was withdrawn. Thus, NGF is as necessary for survival, growth, and differentiation of sympathetic neurons when the neurons express cholinergic functions as when the neurons express adrenergic functions (4, 5).     

The heterosexual affectional system in monkeys.

"We believe that the heterosexual affectional system in the rhesus monkey, like all the other affectional systems, goes through a series of developmental stages—an infantile heterosexual stage, a preadolescent stage, and an adolescent and mature heterosexual stage." Isolation-raised monkeys later displayed severe social abnormalities—a sociopathic syndrome. Monkeys raised with surrogate mothers—rejecting wire frame mothers, air-blast mothers, and infant-shaking mothers—have seldom displayed normal sex behavior. "Month after month female monkeys that never knew a real mother, themselves become mothers—helpless, hopeless, heartless mothers devoid, or almost devoid of any maternal feeling." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functioning oxyphil adenoma of parathyroid gland. An ultrastructural and biochemical study

Oxyphil cells and oxyphil cell adenomas of parathyroid glands are, in most instances, regarded to be nonfunctioning. Although 21 cases of hyperparathyroidism associated with parathyroid oxyphil cell adenoma have been reported, secretion of hormone by these tumors has not been conclusively demonstrated. A parathyroid adenoma, diagnosed by light microscopy as oxyphil type, together with the results from ultrastructural and biochemical studies of the patient's adenomatous tissue, are reported here. The patient, a 64-year-old male, was found to have elevated serum calcium, low serum phosphorus, and elevated serum immunoreactive parathormone: findings consistent with hyperparathyroidism. After excision of two small normal-appearing glands and one greatly enlarged (1.9 g) parathyroid gland, those laboratory values returned to normal. Light microscopy of the enlarged parathyroid indicated that it consisted almost entirely of an oxyphil adenoma. Electron microscopy revealed that the adenoma was composed mainly of mitochondria-rich oxyphil cells but also of interspersed transitional oxyphil cells and rare scattered chief cells. Golgi zones, rough endoplasmic reticulum, and prosecretory and secretory-like granules were observed in some oxyphil cells, in most transitional oxyphil cells, and in the infrequent chief cells. Thus, many of these cells appear to contribute to the production and secretion of parathormone. Biochemical studies performed directly on the adenomatous tissue demonstrated that it was able to synthesize proparathormone and parathormone, although the proportion of hormonal peptide synthesis relative to that of the total protein synthesis in this tissue was much smaller (0.9%) than that found in normal parathyroid tissue (5.7%). There was a small increase in immunoreactive parathormone when the adenoma tissue was incubated in a low-calcium medium. These findings indicate that this oxyphil adenoma of the parathyroid gland synthesized and secreted parathormone, apparently to some extent autonomously, but suggest that its capacity to do so was largely dependent on its component of cells other than fully developed oxyphil cells, such as transitional oxyphil cells.     

浅析中国揭开公司法人面纱制度

<正>何谓"揭开公司面纱"?这一法学术语作为一个一般性规则,直接起源于普通法国家的司法实践。简单地讲,它是关涉导致其他主体(公司债权人及其他股东)经济损失的公司股东及股东自身承担民事责任的方式。一般而言,在我国立法中,公司被拟制为具有独立民事主     

Discrepancies in employer-sponsored health insurance among Hispanics, blacks, and whites: the effects of sociodemographic and employment factors

Using a nationally representative sample of employed adults from the 1987 National Medical Expenditure Survey (NMES), this research explores differences in the incidence and predictors of employer-sponsored health insurance among Hispanics, blacks, and whites. The data suggest that: 1) whites are most likely, and Hispanics are least likely, to have employer-sponsored medical insurance in their own name, or in the name of another individual; 2) Hispanics are most likely, and whites are least likely, to be completely uninsured; and 3) the factors which increase the odds of receiving employer-sponsored coverage in one's own name are relatively similar across racial groups, though they differ substantially in magnitude.