Chromatin degradation in white blood cells of irradiated rats

A study was made of the dose-time relationship during chromatin degradation in white blood cells of non-irradiated and irradiated rats. There was a linear increase in the release of PDN from leukocytes 1,2 and 3 days after irradiation (1-3 Gy) followed by the deceleration of the chromatin degradation at doses exceeding 3 Gy.     

Conjugation transfer of the plasmid pAMbeta1 into various Bacillus species

Streptococcal broad host range plasmid pAM beta 1 was transferred by a conjugation-like process from Streptococcus faecalis to 13 strains of different Bacilli species. In intraspecies matings the frequencies of transfer of pAM beta 1 varied from 2.10(-5) to 1.10(-8). As it was shown by comparative analysis the frequency of transfer and stability of the maintainance of plasmid pAM beta 1 in Bacilli were not connected. Molecular weight and restriction pattern of pAM beta 1 DNA isolated from Bacilli were the same as those of pAM beta 1 DNA from Streptococcal donor strain.     

Effect of metronidazole on the free thymidine content in the blood serum of irradiated mice

The influence of a radiosensitizer, metronidazole, on the free thymidine content of blood serum of irradiated mice was studied in aerobic and hypoxic conditions. A heated metronidazole solution (1 mg/g) was administered intraperitoneally 30 min before irradiation of animals with a dose of 3 Gy. Thymidine concentration in blood serum was determined by the radioimmunological technique. The influence of metronidazole on the level of thymidinemia was only noted in the animals exposed under hypoxic conditions.     

酪氨酸对大鼠子宫胞浆雌,孕激素受体的影响

采用放射受体分析法,测定了动情周期不同阶段及去卵巢大鼠子宫胞浆雌二醇和孕酮受体含量,并观察了子宫腔内注射酪、丝、苏三种氨基酸对子宫胞浆雌。醇、孕酮受体含量的影响。结果表明：（１）Ｌ－酪氨酸对动情前期、动情期、间情期大鼠子宫胞浆雌二醇和孕酮受体都具有明显的降低作用。（２）Ｌ－酪氨酸也降低去卵巢大鼠子宫胞浆雌二醇和孕酮含量,即这一作用不是通过影响卵巢激素分泌实现的。（３）Ｌ－苏氨酸仅可降低动情期和间情期大鼠子宫胞浆孕酮受体含量,而对相应周期雌二醇受体没有明显作用。（４）Ｌ－丝氨酸和Ｌ－苏氨酸对去卵巢大鼠子宫胞浆雌二醇和孕酮受体均无影响。     

人胚DA能神经元移植于帕金森氏病猴模型的TH免疫细胞化学的研究

为了对人胚黑质ＤＡ神经元移植治疗ＰＤ人的临床应用作出客观评估,将８－１２周人胚黑质细胞移植到用ＭＰＴＰ诱发的偏侧ＰＤ猴新纹状体内。实验动物分别存活２个月、５个月和１年后,用ＴＨ免疫细胞化学方法对被移植的人胚ＤＡ细胞的存活和与宿主间的突触联系进行检查。在光镜下可见被移植侧的新纹状体内有ＴＨ阳性细胞,它们成小群散在分布,每小群有３－１０个细胞。ＴＨ阳性细胞的轴突延伸到整个新纹状体,树突呈现出正常发育过     

The inhibition by the tumor necrosis factor of the death and DNA fragmentation of lymphoid cells in irradiated rats]

The influence of a tumor necrosis factor, administered 16 h before irradiation of rats, on the radiation response of thymus and bone marrow cells has been investigated. Three and 6 h after irradiation the following indices were analyzed: the number of apoptotic cells in the thymus; the accumulation of polydeoxyribonucleotides and the appearance of single-strand breaks in DNA of bone marrow and thymus cells; and the electrophoretic properties of thymocyte DNA. The injection of a tumor necrosis factor reduced the number of polydeoxyribonucleotides, inhibited internucleosome DNA fragmentation, and did not influence the formation of single-strand breaks in DNA.     

Control of plasmid incompatibility: characteristics of the bireplicon hybrid pAS8 and its deletion mutants]

The phenomenon of incompatibility has been investigated using deletion mutants of hybrid bireplicon plasmid pAS8. The hybrid pAS8 displays incompatibility specific for both components of its structure. In contrast to P-specificity of pAS8, functions of ColE1-specificity are not effectively expressed. Expression of ColE1-specificity in pAS8 plasmid and its derivatives is characterized by different directions and this is due to the presence or absence of genes of RP4 replication machinery in the plasmid DNA. Mutant plasmids show different efficiency of P-specificity depending on the extension of deletion in the region of essential genes of the RP4 component. Some of the mutants, in spite of the loss of replication genes, including origin of vegetative replication, are incompatible with the representatives of the Inc P group in both directions of testing. Different character and the level of expression of ColE1- and P-specificity in the pAS8 hybrid and its deletion derivatives are not associated with change in the number of plasmid DNA copies, for all of them are subjects to stringent control of replication. The data suggest the existence of incompatibility functions control mechanism which does not seem to include replication genes. Possible ways of realization of the inc genes functions are discussed.     

斑节对虾精子发生的超微结构

斑节对虾精子发生划分为精原细胞、初级精母细胞、次级精母细胞、精子细胞和精子五个阶段。精子发生中，从精原细胞到精子，染色质经历了从以异染色质为主变为高度凝聚态，再经解聚为弥散絮状的变化过程。同时，核从具有完整核膜变为核膜不完整。成熟的的精子含有核仁。顶体由高尔基囊泡逐渐演化而成，并向外伸长成为棘突。这是斑节对虾精子发生的主要特征。     

Endonucleolysis of chromatin in thymocytes of irradiated and non-irradiated rats

It was shown that in conditions optimal for Ca/Mg endonuclease, chromatin endonucleolysis in the nuclei and thymocytes occurs due to internucleosome fragmentation of DNA. Irradiation activates chromatin degradation in thymocytes washed by a buffer containing 0.25 M sucrose, 10 mM tris-HCl, pH 7.2, 3 mM MgCl2, and does not influence this process in thymocytes washed by 10 mM tris-HCl, pH 7.2, 3 mM MgCl2.