Theoretical investigations on circular and chain-like hydrogen bonded structures found in two crystal forms of α-cyclodextrin hexahydrate: Models for hydration and water clusters

Hydration of macromolecules and the structure of water of crystallization are not understood in detail because in these complex systems. H-atoms cannot be located and the hydrogen bonding schemes are not known. X-ray and neutron diffraction studies on a hydrated oligosaccharide, α-cyclodextrin 6H₂O, ((C₆H₁₀O₅)₆·6H₂O), crystals forms A and B, gave insight into the chain-like and circular arrangement of hydrogen bonds. In the circles, homodromic (unidirectional) and antidromic (counter-running) orientation of five to six hydrogen bounds is observed. PCILO calculations showed that homodromic circles and chains are approx. 8% per hydrogen bond more stable than antidromic circles, that the changes in electronic charges on H and O atoms are greater in homo than in antidromic systems and that the dipole moments are only approx. 3 D in the homodromic circles but 6–8 D in chain-like and antidromic arrangement. These results have been interpreted in terms of cooperative effect. Circular systems are considered as structural elements in hydration shells of macromolecules and in the assembly of ‘flickering’ water clusters.     

In vitro construction of a recombinant adenovirus Ad2:Ad5

A hybrid virus containing the left half of the Ad5 genome and the right half of the Ad2 genome has been constructed by ligating together in vitro the BamHI.-A fragment of Ad5 (map co-ordinates 0–59.5) to the-SawHI-A fragment of Ad2 (map coordinates 59.5–100), and using this DNA to transfect susceptible cells. Viable progeny virus has been obtained which grows as well as the parental virus without any requirement for helper virus, and probably contains a hybrid hexon polypeptide consisting of the major part of the Ad5 hexon with an Ad2 carboxy terminus.     

Construction of plasmids that produce phage P22 repressor

In a series of plasmid constructions, the c2 (repressor) gene of phage P22 was cloned in a multicopy plasmid and expressed at increasing level. The final result of these constructions is a plasmid that maintains a level of approx. 200 times as much repressor as is found in a lysogen. A series of increasingly virulent phage mutants was isolated by plating sequentially on host cells with increasing levels of repressor. The methods used in the constructions should be applicable to obtaining elevated expression of cloned genes in other systems.     

Structure of F1-ATPases

F₁-ATPases are large multimeric proteins that can be isolated from the membrane bound system that catalyzes the phosphorylation of ADP by inorganic phosphate in bacteria, plants, and mitochondria. They can be visualized in electron micrographs of the inner mitochondrial membranes where they appear as large protruding spheres 90 Å in diameter. The purified F₁-ATPases have a molecular weight of 320,000 to 400,000 daltons and are composed of five non-identical subunits (, , , and ). The stoichiometry of these subunits in the complex is still unknown but compositions of the type ₃₃ and ₂₂₂₂₂ were found to be consistent with some of the available experimental data. This review discusses the recent data and the experimental approaches utilized for the structural characterization of F₁-ATPases.     

Pharmacological comparison of bPTH-(1–34) and other hypotensive peptides in the dog

The purpose of the present study was to compare the potency, effectiveness and duration of action of synthetic bPTH-(1–34) with those of other known hypotensive peptides in the anesthetized dog. Of sixteen peptides tested in the present study only 8 were demonstrated to possess hypotensive activity. While bPTH-(1–34) was one of the least potent of the hypotensive peptides, it was equal to or greater than the other peptides in terms of effectiveness and duration of action. Of all the peptides studied, substance P and eledoisin were the most potent in terms of their hypotensive action. It is suggested that perhaps substance P and eledoisin might act at a different site or through different mechanisms than do vasoactive intestinal peptide (V.I.P.), corticotropin inhibiting peptide (C.I.P.), neurotensin, xenopsin, bradykinin and bPTH-(1–34).     

Circadian placebo and ACTH effects on urinary cortisol in arthritics

The effect of placebo and ACTH-1-17 (Synchrodyn®, Hoechst) upon urinary free cortisol was examined at 5 different circadian stages on 10 men with Steinbrocker Stage II–III rheumatoid arthritis. A mean cosinor analysis of urinary cortisol data from the subjects prior to treatment with either ACTH or placebo revealed a statistically highly-significant rhythm. A circadian variation in a response of urinary free cortisol to a placebo was also seen. Moreover, the response of the midline-estimating statistic of rhythm (rhythm-adjusted circadian average) of urinary free cortisol to ACTH-1-17 by patients with rheumatoid arthritis is circadian rhythmic. This reactivity rhythm is out of phase with the spontaneous rhythm in urinary cortisol acrophases—in the tests limited thus far to midsummer. The further assessment of the circadian component in the context of broader interactions by rhythms with other frequencies in various conditions in health and disease is warranted by the demonstration of rhythms here presented for men with rheumatoid arthritis.     

Non-random X-chromosome expression early in mouse development

We have used a sensitive electrophoretic technique for estimating the activity, or ratio, of two allozymes of the X-chromosome-linked enzyme phosphoglycerate kinase (PGK-1), in order to investigate the randomness of X-chromosome expression in the derivatives of the three primary cell lineages of the early mouse conceptus. The maternally derived Pgk-1 allele is preferentially expressed in the derivatives of the primitive endoderm and trophectoderm lineages at 6 1/2 days post coitum in Pgk-1^a/Pgk-1^b heterozygous conceptuses, and in the one informative 5 1/2-day heterozygous conceptus analysed. This evidence for preferential expression of the maternally derived X chromosome (X^m), so soon after the time of X-chromosome inactivation, favors the possibility that the preferential expression of X^m is a consequence of primary non-random X-chromosome inactivation, rather than a secondary selection phenomenon. The majority of embryos analysed at 4 1/2 and 5 1/2 days pc produced only a single PGK-1 band, corresponding to the allozyme produced by the Pgk-1 allele on X^m, although 50% of these embryos should have been heterozygous females. Possible explanations are discussed.     

Hybridoma monoclonal antibodies in the analysis fo human cell surface antigens

Summary In the present paper, we will summarize studies we have performed on two distinct human lymphocyte cell surface antigens defined by monoclonal antibodies: Leu-1 and HLA-DR. Presented in the symposium on The Biology of Hybridomas at the 32nd Annual Meeting of the Tissue Culture Association, Washington, D.C., June 7–11, 1981. This work was supported by USPHS-NIH Grants CA-21223, AI-11313, and CA-09302. This symposium was supported in part by the following organizations: Bethesda Research Laboratories, Cetus Corporation, Hybritech Incorporated, MAB-Monoclonal Antibodies, Inc., National Capital Area Branch of the Tissue Culture Association, New England Nuclear Corporation, and Ortho Pharmaceutical Corporation.     

乙型脑炎病毒NS2A-C60A位点突变对其生物学特性影响研究*

目的:旨在探索Ⅰ型日本乙型脑炎病毒传代致弱后基因组突变NS2A-C60A对乙脑病毒生物学特性的影响。方法:首先通过对传代致弱及原始乙脑毒株基因组序列进行测序比对、结构预测分析并利用Western blotting(WB)确定了目标研究位点NS2A-C60A;然后使用反向遗传定点突变技术构建拯救了包含NS2A-C60A单点突变的病毒株;最后利用噬斑形态观察、生长曲线、双萤光素酶分析,WB以及炎性因子检测和动物实验研究了该单点突变对于乙脑病毒生物学特性的影响。结果:首次研究发现Ⅰ型乙脑病毒传代致弱会导致NS1'蛋白表达的显著下降以及可能的相关位点NS2A-C60A,并成功拯救获得了NS2A-C60A单点突变毒株rJEV-C60A,研究发现NS2A-C60A突变对乙脑病毒的生长特性及噬斑形成没有显著影响,但是能够显著降低乙脑病毒NS1'蛋白的表达,并且该位点突变能够轻微阻碍乙脑病毒对细胞炎性因子表达的抑制,动物实验结果显示NS2A-C60A点突变病毒与原毒株具有相似的神经毒力,说明该位点突变不是影响乙脑病毒毒力致弱的关键位点。结论:新发现的NS2A-C60A位点突变能够显著减少乙脑病毒NS1'蛋白的表达,但是对其增殖、诱导炎症及神经毒力等生物学特性没有显著影响。