樗蚕丝腺5SrRNA的核苷酸顺序

本文用凝胶直读法、末端鉴定法等相配合,测定了樗蚕(Philosamia cynthia)絲腺5SrRNA的核苷酸顺序:AGACAACGUCCAUACCACGUUGAAAACACCGGUUCUCGUCCGAUCACCGAAGUCAAGCAACGUCGGGCGCGGUCAGUACUUGGAUGGGUGACCGCCUGGGAACACCGCGUGCUGUUGGCUU比较了樗蚕、蓖麻蚕、柞蚕、家蚕、果蝇等5SrRNA结构差异,在分子水平上探讨了昆虫的分化。     

Hemodynamic interactions between intrinsic blood flow control mechanisms in the rat kidney

In order to reconcile the controversial concepts of myogenically and tubuloglomerular-feedback (TGF)-mediated control of renal vascular resistance, a hypothesis is advanced according to which both mechanisms interact hemodynamically because of their serial arrangement. Whereas the myogenic mechanism is suggested to be localized in the more upstream segments of the preglomerular resistance vessels, the TGF mechanism is assumed to control the pre- and/or postglomerular vascular segment(s), close to the glomerular vascular pole. The efferent vascular resistance, however, is assumed to function generally akin to a 'passive' flow resistor. These assumptions together with elementary hemodynamic considerations, allow formulation of a simple renal hemodynamic model whose quantitative predications regarding the characteristics of RBF, GFR and TGF control are remarkably consistent with the literature: (1) the magnitude of TGF response is mainly dependent upon the myogenic cooperative amplification and (2) although the TGF mechanism is not involved in the autoregulative control of RBF and GFR, changes of the TGF function may shift the autoregulation curve to higher or lower RBF and blood pressure levels.     

固定化酶的微环境效应—载体离子基团性质的影响

作者合成了阴离子型和阳离子型葡聚糖,以此为载体,用CNBr活化其剩余羟基,固定化了葡萄糖淀粉酶和葡萄糖异构酶。就离子型载体对固定化酶的蛋白载量、最适pH和热稳定性等的影响做了考察。发现固定化酶的蛋白载量不仅与载体的电性质有关,也与酶分子自身的电性质有关。当载体电性质与酶蛋白电性质相反时,固定化酶的蛋白载量增加,热稳定性提高、载体电性质与酶蛋白电性质相同时,固定化酶的蛋白载量不变或下降,其热稳定性不变。作者还发现当离子型载体孔度和体系缓冲液浓度一定时,酶分子能否进入多孔性载体内部,对其最适pH是否变化影响极大。若酶分子仅被连接在载体的外表层,其最适pH不发生变化,反之亦然。作者还观察到当多糖类载体引入氨基或羧基后,大大增强了其抵抗微生物侵蚀的能力。     

Restriction analysis of Thiobacillus ferrooxidans DNA using pulsed field electrophoresis]

The DNA of Thiobacillus ferrooxidans digested by any of the five restriction endonucleases (DraI, EcoRI, Eco321, HindIII, XbaI) was studied by electrophoresis in the pulsating differently directed electric fields (PF). The influence of PF conditions on the sized row of the divided DNA fragments was studied. Only the XbaI restriction endonuclease was shown to cleave the Thiobacillus ferrooxidans DNA into a number of fragments permitting one to define the sizes of fragments and genome (no more than 2300 bp). The prospects of using the restriction analysis of Thiobacillus ferrooxidans wild type culture for improving its properties in obtaining heavy metals are discussed.     

Lesion and regeneration in the medial cerebral cortex of lizards.

The cerebral cortex of Squamate reptiles (lizards and snakes) may be regarded as an archicortex or "reptilian hippocampus". In lizards, one cortical area, the medial cortex, may be considered as a true "fascia dentata" on grounds of its anatomy, connectivity and cyto- chemo-architectonics of its main zinc-rich axonal projection. Moreover, its late ontogenesis and postnatal development support this view. In normal conditions, it shows delayed postnatal neurogenesis and growth during the lizard's life span. Remnant neuroblasts in the medial cortical ependyma of adult lizards seasonally proliferate. The late-produced immature neurocytes migrate to the medial cortex cell layer where they differentiate and give off zinc-containing axons directed to the rest of cortical areas. This results in a continuous growth of the medial cortex and its zinc-rich axonal projection. Perhaps the most important characteristic of the lizard medial cortex is that it can regenerate after having been almost completely destroyed. Recent experiments in our laboratory have shown that chemical lesion of its neurons (up to 95%) results in a cascade of events; first, those related with massive neuronal death and axonal-dendritic retraction and, secondly, those related with a triggered neuroblast proliferation and subsequent neo-histogenesis, and the regeneration of an almost new medial cortex that shows itself undistinguishable from a normal undamaged one. This is the only report to our knowledge that an amniote central nervous centre may regenerate by new neuron production and neo-histogenesis. Perhaps the medial cortex of lizards may be used as a model for neuronal regeneration and/or transplant experiments in mammals or even in primates.     

Comparative effectiveness of various antibiotics in the treatment of patients with meningococcal meningitis]

The results of treating 322 patients with various forms of meningococcal infection accepted to a hospital within a year are presented. The patients were divided into 3 groups by the character of etiotropic therapy. The patients of group I were treated with benzylpenicillin and those of group 2 were treated with levomycetin sodium succinate. Group 3 included the patients, the therapy of whom with the above two antibiotics failed and they were subjected to treatment with cefazolin, cefotaxime, amikacin and other broad spectrum antibiotics. Benzylpenicillin generally proved to be the drug of choice in the antibacterial therapy of meningococcal infection. In comparison to levomycetin (chloramphenicol) it provide more rapid clinical recovery of the patients and normalization of the indices of the cerebrospinal fluid. Only failure of benzylpenicillin therapy was considered as an indication to the broad-spectrum antibiotics to be in the complex treatment of the patients. As additional methods for estimating the efficacy of antibacterial therapy it was recommended to employ calculation of the integral indices of hemograms (the leukocyte index of intoxication and the hematologic index of intoxication).     

Current methods for the laboratory diagnosis of campylobacteriosis]

An analytical review of recent publications of home and foreign authors on the problem of laboratory diagnosis of campylobacteriosis is presented. The commercial nutrient media, methods of creation of the microaerophilic conditions for cultivation of campylobacter are presented. The filtration method is preferable for isolation of these agents from the studied material highly contaminated by accompanying microflora. A special attention is paid to immunodiagnosis of campylobacteriosis: agglutination reaction, coagglutination reaction, passive hemagglutination reaction, immunoenzyme and radioimmune analyses. Seroepidemiological examination of the staff at one of meat-packing factories in the Republic carried out by the method of indirect immunoenzyme analysis has revealed high levels of anticampylobacteriosis antibodies in 17.9% of examinees. The promising trends in perfection of the methods for laboratory diagnosis of campylobacteriosis are outlined.     

Functional asymmetry of the brain and effectiveness of sensorimotor function of oral cavity organs]

It has been established that in healthy persons functional brain asymmetry positively influences the effective performance of sensomotor function of oral cavity organs. Individual brain asymmetry is of considerable importance, the higher it is, the quicker the final results of sensomotor function are achieved. The character of brain asymmetry (right hand or left hand) does not practically influence the performance of sensomotor functions.     

In vivo topoisomerase II cleavage of the Drosophila histone and satellite III repeats: DNA sequence and structural characteristics.

We have identified two classes of in vivo topoisomerase II cleavage sites in the Drosophila histone gene repeat. One class co-localizes with DNase I-hypersensitive regions and another novel class maps to a subset of consecutive nucleosome linker sites in the scaffold-associated region (SAR) of the histone gene loop. Prominent topoisomerase II cleavage is also observed in one of the linker regions of the two nucleosomes spanning satellite III, a centromeric SAR-like DNA sequence with a repeat length of 359 bp. At the sequence level, in vivo topoisomerase II cleavage is highly site specific. Comparison of 10 nucleosome linker sites defines an in vivo cleavage sequence whose major characteristic is a prominent GC-rich core. These GC-rich cleavage sites are flanked by extensive arrays of oligo(dA).oligo(dT) tracts characteristic of SAR sequences. Treatment of cells with distamycin selectively enhances cleavage at nucleosome linker sites of the SAR and satellite regions, suggesting that AT-rich sequences flanking cleavage sites may be involved in determining topoisomerase II activity in the cell. These observations provide evidence for the association of topoisomerase II with SARS in vivo.