Scientia Sinica最新文献

[Trp]B1 analogs to porcine and bovine insulins have been obtained through selective reaction with Msc-ONSu, and followed by Edman degradation, condensation with Msc-Trp-ONp and deprotection. Through cellulose acetate electrophoresis, amino acid composition analysis, UV absorption spectrum and N-terminal analysis, it has been proved that the products are of purified [Trp]B1 insulin. Mouse convulsion assay shows that the biological activities of porcine and bovine [Trp]B1 insulins are 18 i.u./mg and 17 i.u./mg respectively, corresponding to about 70% of the original activity of native porcine insulin. Their structural details are under investigation in our laboratory.

Porcine trypsin obtained from pancreas residues subsequent to insulin removal undergoes autolysis when subjected to chromatography and gives rise to new forms of autolyzed products with intra-chain split at bonds Lys145-Ala146 and Arg105-Val106. Incubation of 1% solutions of porcine trypsin either at pH 5.0 or at pH 9.1 induces autolysis to give active products involving one or two specific cleavages of bonds Lys145-Ala146 and Arg105-Val106 or Lys131-Ser132, as well as inactive degraded products. No evidence has been obtained that on autolysis of porcine trypsin, and active fragment with molecular weight lower than that of the parent molecule was identified. The active forms of autolyzed products of porcine trypsin have almost the same specific activity as the intact enzyme when assayed against BAEE. They are of the same molecular weight as the parent molecule. These findings indicate that that active forms of autolyzed products maintain the specific three-dimensional structure essential for the catalytic activity of the trypsin molecule.

We have worked out a new adsorption method for the preparation of insulins from different species. At present, we are mainly involved in chicken and snake insulins. In all insulins so far studied, only chicken insulin has been reported to have much higher activity. However, results from different laboratories are quite different from one another. We have obtained chicken insulin in typical rhombohedral crystalline form and determined its activity in vivo which is not appreciably different from that of porcine insulin. From the pancreas of a non-venomous snake, Zaocys dhumnades dhumnades (Cantor), we have prepared snake insulin which is different from rattle snake insulin reported earlier. The dodecahedral crystals of the snake insulin are similar to those of zinc-free porcine insulin.

In May 1975, one female mountaineer and eight male mountaineers of our country once more climbed onto the highest peak of the world Mount Qomolangma from the north slope. At the same time, we recorded 15 electrocardiograms while they were climbing from 7,600 m to the peak(8,848.13m) through radio-operated electrocardiography. In this report we mainly analyze the characteristics of electrocardiogram of six mountaineers who ascended the peak at the stage from 50 m a. s. l. to over 8,200m a. s. l. The result proves that although obvious changes after reaching an altitude above 8,200 m from the plain region should be those of indexes of heart rates, the QRS axis, Q-TR, Q-T/T-Q, P wave and T wave, there is no T wave diphasic, inverted, flat or abnormal shifting of S-T segment in the electrocardiogram of these outstanding mountaineers. This fully proves that those summit climbers are of excellent constitution and good adaptation ability to hypoxia. This also shows that the people who have been trained and acclimatized under hypoxia conditions (including permanent altitude residents and native lowlanders) can maintain normal physiological functions under ultra-anoxia for quite a long time.

This paper briefly presents the results of the systematic observation of the chronic irradiation of 60Co-gamma-ray on rhesus monkey (Macaca mulatta) at low dose rate. It also provides valuable experimental data on the estimation of the damage of long-term irradiation on human beings at low dose rate.

Since there are several endogenous morphine-like substances differing in distribution and probably also in function, it seems necessary to study their roles in acupuncture analgesia separately. Therefore we set up a sensitive and specific radioimmunoassay (RIA) for met- and leu-enkephalin, and employ it in determining the changes of enkephalin contents in the brain regions and CSF during acupuncture. The main results are as follows: (i) Two enkephalins increase markedly in hypothalamus and striatum during acupuncture analgesia. (ii) Prior intraventricular bacitracin enhances the acupuncture analgesia with concomitant increased contents of enkephalins in the brain and CSF. (iii) Cycloheximide, the protein-synthesis inhibitor, reduces the enkephalin-increasing effect of acupuncture, indicating that one of the mechanisms by which acupuncture elevates the enkephalin levels is the acceleration of biosynthesis. (iv) After surgical isolation of rat hypothalamus, the effect of electric acupuncture is attenuated. This indicates that hypothalamus takes part in acupuncture analgesia.

Electron microscopy of purified Chlamydia trachomatis treated by various physical and chemical means shows that the envelope of the elementary bodies (EB) consists of the outer cell wall layer, the inner cell wall layer, and the inner membrane. The outer cell wall layer is mainly made up of granular subunits arranged in a hexagonal pattern and may be called the "mural structural protein layer". It forms together with the inner cell wall layer the rigid cell wall. The inner or protoplasmic membrane is not easily shown in the young EB. In the negatively stained specimen, a frail and easily removable superficial layer is seen adhering to the "mural structural protein layer". But in ultra-thin sections this superficial layer is not shown separately. There are fold-like grooves which are special structures probably related to reproduction. There are seen some EB's in binary fission, and a number of bodies very big in size yet having morphological characteristics of the EB's, which are in various processes of multiplication, such as binary fission, budding, and "multicentered germination". These observations give a challenge to the current opinion that only the initial bodies have the power of reproduction.

Using cloned viruses of proven purity, and by the methods of hemagglutination inhibition, single radial hemolysis, strain-specific complement fixation and neutralization tests we have demonstrated the serological cross reaction between late H1N1 variant (Dutch/56) and H2N2 of influenza A virus with fowl and hamster antisera. Such a cross reaction is not detected with earlier H1N1 variants. Serological crossing covers variants of H2N2 virus isolated from 1957-1966 but in decreasing titers, and disappears with the last variant of H2N2 isolated late in 1967. Analysis with mono-specific antisera or antigens prepared with recombinants reveal that the hemagglutinins of late H1N1 and H2N2 are related, while their neuraminidases are distinct. We have discussed the bearing of such antigenic relationships to previous epidemiological observations on the partial protection of patients convalescent from late H1N1 disease against H2N2 and to the recombination theory for the origin of H2N2 virus.

Prothoracicotropic hormone has been successfully extracted from as many as 2,800,000 silkworm male adult heads and purified partially through an 8-step procedure. Approximately 7 microgram of the crude preparation ("crude PTTH") shows activity in the debrained Samia pupa test. A further 4-step chromatographic purification of the "crude PTTH" derived from 100,000 Bombyx heads yields 3.4 mg of purified preparation ("highly purified PTTH"), of which 7 ng causes adult development in a debrained Samia pupa.