Human DNA sequences exhibiting gamete-specific hypomethylation.

Three human DNA sequences have been cloned from DNA regions which are strikingly undermethylated in sperm, highly methylated in adult somatic tissues, and methylated to an intermediate extent in tissues of extraembryonic origin. It is proposed that some such DNA sequences may function specifically early in embryogenesis or during gametogenesis. They may be subsequently extensively methylated in the embryonic cell lineage and methylated to a lesser extent in extraembryonic tissues in order to allow embryogenesis to proceed.     

Estimation of the mechanical parameters of the human respiratory system

A numerical algorithm has been developed for the estimation of the mechanical parameters of the human respiratory system. In order to estimate the pulmonary resistance and the dynamic pulmonary elastance, the transpulmonary pressure and the airflow at the mouth or nose are expanded in Chebyshev series. The nonlinear mathematical lung model and a set of measurements for airflow and pressure are then handled by the numerical technique. The lung model includes a component to account for turbulent flow in the larynx and trachea. This contribution presents an alternative method for lung parameter estimation and differs from most existing methods in that it does not need measurements for the tidal volume. It therefore eliminates the use of a body plethysmograph. The method may also find potential application to various other parameter identification problems.     

在甜椒花药培养中马来酰胼对小孢子发育的抑制作用

选用甜椒的小孢子单核期花药,用100、300、500、2000ppm的马来酰肼溶液浸泡处理,并设对照,进行无激素MS固体培养基培养。分别取样用各种组化方法对花药内部多糖、蛋白质、核酸及ATP酶进行组化反应和形态学上的观察。与对照组相比,处理组花药外部形态和内部结构出现许多变异。小孢子内多糖,蛋白质含量减少;绒毡层无明显变化;两组中,核酸的含量均无明显变化;ATP酶的活性低于对照组。可能,马来酰肼对于花药中ATP酶等产生抑制作用,致使花药败育。     

云南开远新发现的腊玛古猿化石

本文描述的标本是1980年6月和1982年5月,在云南开远小龙潭晚中新世褐煤层中发现的古猿化石。标本有左下第一至第三臼齿列和一件带十二枚牙齿的上颌骨。从标本反映的形态特征观察,应归为腊玛古猿。     

海枣曲霉β-半乳糖苷酶的提纯与性质

 通过过聚乙二醇6000-磷酸钾缓冲液双相分离、Sephadex G-100凝胶过滤、DEAE-Sephadex A-50离子交换层析、羟基磷灰石层析及SephadexG-100凝胶过滤等提纯步骤,从海枣曲霉(Aspergillus phoenicis)麦麸培养物抽提液中提纯得到凝胶电泳均一的β-半乳糖苷酶。该酶的最适pH为3.5—4.0,最适温度为60℃(反应15分钟),在pH5.0—8.5之间及60℃以下稳定。在65℃和70℃保温时失活50％的时间分别为27和2分钟。用SDS凝胶电泳法和梯度凝胶电泳法分别测得该酶的分子量为115,000和118,000。薄层凝胶等电聚焦法测得其等电点为pH4.6。     

Morphological changes of sensory CGRP-immunoreactive and sympathetic nerves in peripheral tissues following chronic denervation

The morphological relationship between sensory and sympathetic nerves was studied in tissues of the eye and the oral cavity following chronic sympathetic or sensory denervation. Immunoreactivities for calcitonin gene-related peptide (CGRP) and tyrosine hydroxylase (TH) were used as indexes to assess the changes of the two nerve populations after denervation. Following surgical sympathectomy, a marked increase of CGRP-containing fibres was seen in all tissues studied, while TH-imunoreactive fibres were totally depleated. Conversely, after capsaicin treatment, an increase of TH-immunoreactive nerves was found in the same tissues, concomitant with a sharp decrease of CGRP-immunoreactive nerves. These changes were particularly evident in iridial stroma and around blood vessels in all tissue, where sensory and sympathetic nerves have a closely overlapping distribution pattern. The altered proportion of sensory peptide- and catecholamine-containing nerves following sympathetic and sensory denervation suggest that there is a reciprocal trophic influence between the two nerve subsets, possibly with the intervention of neurotrophic substances such as nerve growth factor. These results indicate a close interaction between sensory peptidergic and sympathetic nervous systems in peripheral organs.     

二十三种药用种子(或果实)中油的化学组成

本文报道了二十三种药用种子(或果实)的含油率和油的化学组成成分,它们分属于二十个科二十二个属中。本文所发表的大部分资料尚未见国内外文献的报道。     

Preparation of [B23-D-alanine]des-(B25-B30)-hexapeptide-insulin by a combination of enzymic and non-enzymic synthesis.

Des-(B25-B30)-hexapeptide-insulin with B23-glycine replaced by D-alanine was prepared by a combination of enzymic and non-enzymic syntheses. The purified product was homogeneous in polyacrylamide-gel electrophoresis and could be crystallized. The biological activity in vivo of crystalline [B23-D-Ala]des-(B25-B30)-hexapeptide-insulin was determined as 58% of that of standard pig insulin (27 i.u./mg).     

Calorimetric measurement of free energy utilization by Nitrosomonas and Nitrobacter

Summary Calorimetric estimates of the utilization efficiency of the free-energy derived from substrate oxidation by cell suspensions of two nitrifying bacteria, Nitrosomonas and Nitrobacter, provided two ranges of values: 11 to 27% and 15 to 51%, respectively. About 15 to 30% of the utilized free-energy is used for driving endergonic reactions other than CO₂ fixation, probably the synthesis of polyphosphates.The molar heat of substrate oxidation does not seem to be influenced by the age of cells harvested during growth or by the length of the incubation period during which cells have been kept in a buffer suspension in a starved condition. The loss of respiratory activity measured either by oxygen uptake or heat evolution in the presence of the specific substrate, nitrite or ammonium, decreases according to kinetics which are influenced by the aerobiosis of the suspension. The viability of the starved cells decreases in a way which is similar to that of the respiratory activity. It seemed impossible to obtain cells which had lost their viability but kept the ability to oxidize their substrate.Two inhibitors of the respiratory chain, quinacrine and cyanide, are without effect on the molar heat of substrate oxidation and consequently on the free-energy utilization efficiency. 2.4 dinitrophenol did decrease the rate of heat evolution during substrate oxidation at concentrations at which the rate of oxygen uptake was not depressed, with the consequences that free-energy efficiency was apparently increased.