漳泽水库水体污染对黑斑蛙蝌蚪遗传毒性的野外调查研究

通过野外采集漳泽水库不同采样点的黑斑蛙蝌蚪,采用微核、核异常、彗星试验3种方法,研究了水体污染对蝌蚪红细胞微核率、核异常率和DNA断裂3种遗传毒性指标的影响。微核试验结果显示:各采样点红细胞微核率除泽头采样点外,均明显高于阴性对照(P0.01),其中水库入口店上采样点的微核率最高,为6.87‰,位于水库上、中、下游3个采样点的微核率逐渐下降,从大到小依次为:下韩(5.45‰)、台上(3.71‰)、泽头(2.33‰)。核异常试验结果显示:各采样点核异常率均明显高于阴性对照(P0.01),核异常率与微核率二者变化趋势趋于一致。彗星试验结果显示:各采样点红细胞尾长、尾矩与阴性对照相比差异均极显著(P0.01),尾长、尾矩的变化趋势与微核试验结果一致。对同样位于水库中游的采样点司徒和台上的4个指标进行多重比较分析发现:微核率、核异常率和彗星尾长差异均不显著(P0.05),而尾矩差异显著(P0.05)。综上可知,漳泽水库各采样点水体具有较高的遗传毒性,主要毒性作用为引起染色体(DNA)断裂;各采样点遗传毒性指标变化规律与水体污染物变化规律趋于一致,因此应用这3种方法可以有效地对水体遗传毒性进行检测。     

Effect of latex material on antioxidant enzymes,lipid peroxidation,DNA damage,and chromosomal aberration

Cell integrity is affected by oxidative stress when the production of active oxidants overwhelms antioxidant defense mechanisms. Latex, a natural polymer obtained from Hevea brasiliensis, is used in medical industry for manufacturing surgical gloves, urinary catheters, and dental dams. The aim of this study was to evaluate the effects of latex material on oxidative stress by in vivo and in vitro methods. In addition, the material was screened for its ability to induce any chromosomal aberrations (CAs) by in vitro method. In vivo studies were carried out with implanted latex material onto subcutaneous tissue of various batches of experimental Wistar rats. At the end of experimental period, animals were anesthetized, blood was collected for serum analysis, and sacrificed. Liver was excised for the determination of antioxidant enzymes and lipid peroxidation (LPO). Subcutaneous tissues were obtained for the extraction of genomic DNA from implanted animals and checked for the presence of 8-hydroxy-2-deoxyguanosine (8-OHdG), considered an indicator of DNA damage. Simultaneously, in vitro studies were carried out using fresh liver and subcutaneous tissue obtained from Swiss albino mice treated with physiological saline extract of latex material. For the estimation of both in vitro and in vivo oxidative stress, 10% liver homogenate was assessed for stress indicators like reduced glutathione, glutathione reductase, glutathione peroxidase, LPO and protein content. The results of both in vivo and in vitro studies indicated that the chemical leachents from the latex material did not significantly affect LPO and the levels of antioxidant enzymes. There was also no significant increase in 8-OHdG content due to the presence of implanted latex material. Finally, the results of in vitro CA test and G banding indicated that extracts of test material did not induce any chromosomal abnormalities.     

In vitro assessment of genotoxic and oxidative effects of zinc borate

Zinc borate is used as flame retardant for plastics and cellulose fibers, paper, rubber, and textiles. Despite its wide industrial use, there is limited information concerning its toxicity. The aim of the present study was to investigate the concentration dependence (0–280 mg L^?1) of its genotoxic activity on cultured human lymphocytes by using sister chromatid exchange and chromosomal aberration assays. Total antioxidant capacity and the extent of oxidative stress were also determined. Zinc borate was found to be non-genotoxic at all tested concentrations. It exhibited antioxidant activity at concentrations lower than 40 mg L^?1, and total oxidative stress levels were not changed at any applied concentration of zinc borate.     

Solubility of anthracene in complex solvent systems

A very extensive and effective research in the fields of classical and molecular cytogenetics of cancer cells, during the past 10 years, has produced a rather concrete picture of the events and mechanisms rendering a normal cell a malignant one: Mutational changes in the control of so‐called cellular oncogenes play a fundamental role in cell transformation and tumor progression. These oncogenes are highly conservative and, therefore, important genes normally coding for a series of specific proteins particularly involved in growth control and differentiation processes.

The most important alterations of these genes are: (1) Point mutations (e.g. base transitions) in essential base pairs of the respective proto‐oncogenes causing an uncontrolled expression of the latter, (2) translocations of specific chromosomal segments resulting in transfer of a proto‐oncogene from its normal (controlled) location into the area of highly active genes and by that in its activation, (3) amplification of DNA sequences including proto‐oncogenes which also can cause their over‐expression, (4) insertion of retroviral oncogenes into the DNA, (5) point mutations or deletions in “control genes” rendering the respective gene mutation homozygous or hemizygous.

All these events are mutations in the strict sense the mutageneticist applies to the endpoints of his experimental studies. Above all, the fundamental importance of translocations and point mutations in the transformation process has clearly been evidenced by these data. Therefore, the design of experiments in mutagenicity testing should preferentially consider these types of mutations. Any mutagen, e.g. certain heavy metals or their compounds, inducing those types of mutations, must be considered suspicious not only concerning its mutagenicity in germ cells but also in somatic cells, and, by that, its carcinogenicity.     

重金属对大麦(Hordeum vulgare)毒性的研究

研究了６种重金属（Ｈｇ２＋、Ｃｄ２＋、Ｐｂ２＋、Ｎｉ２＋、Ｃｕ２＋、Ｚｎ２＋）对大麦幼苗生长及根尖细胞遗传学毒害作用．结果表明，随着重金属浓度的增加和处理时间的延长，大麦种子的萌发率、根生长速率和有丝分裂指数下降．１×１０－２ｍｏｌ／Ｌ的Ｈｇ２＋、Ｃｄ２＋、Ｐｂ２＋处理２４ｈ后完全抑制了细胞分裂，Ｈｇ２＋、Ｃｄ２＋和Ｐｂ２＋诱发的染色体畸变率显著高于Ｎｉ２＋、Ｃｕ２＋和Ｚｎ２＋．用５×１０－３—５×１０－４ｍｏｌ／Ｌ的Ｈｇ２＋、Ｃｄ２＋、Ｐｂ２＋处理２４ｈ和Ｎｉ２＋处理４８ｈ后，核仁结构发生分解，形成许多核仁颗粒并进入细胞质中，而Ｃｕ２＋、Ｚｎ２＋对核仁结构没有影响．６种重金属对大麦的细胞遗传学毒性顺序为Ｈｇ２＋＞Ｃｄ２＋＞Ｐｂ２＋＞Ｎｉ２＋＞Ｃｕ２＋＞Ｚｎ２＋．文中还讨论了重金属对植物细胞的毒害机理．     

Genotoxicity study of high aspect ratio silver nanowires

The genotoxicity potential of silver nanowires synthesized via the solution-based polyol method has been investigated. They were found to be non-mutagenic in three Salmonella strains and were not genotoxic in a clastogenicity assay in mice. Residual surfactant was found to have an effect on the toxicological properties of the nanowires by increasing the rate of Ag⁺ release. Residual surfactant can be easily degraded via a UV treatment.     

亚硝基胍对泥鳅红细胞微核及核异常的诱发

研究了诱变剂对泥鳅红细胞微核和核异常的诱发作用,以寻求较为简便的检测水体中污染物对遗传物质的损害程度及毒理效应的方法。试验以亚硝基胍（MNNG）作为诱变剂,研究其不同浓度和染毒时间对泥鳅红细胞微核形成和核异常的影响。试验结果表明,在一定浓度范围内,微核细胞率与亚硝基胍浓度呈正相关;但当浓度过高时,微核细胞率反而降低。此外,研究还发现,随着亚硝基胍浓度的升高,微核细胞率出现高峰的时间也相应提前。从试验结果来看,微核测定法确是遗传毒理学试验中一个较为理想的监测手段。     

R值评分方法的再学习

详细介绍了目前最常用的预报效能评价R值评分方法的基本内容和不同公式 ,分析了计算R值评分时所选用参数和使用公式不同对R值的影响。以便能正确应用R值评分方法并对R值预报效能评价结果有一清晰的认识     

Changes in the sex structure of pine populations related to temperature anomalies

The results of ten-year observations on fluctuations in the sex of individual trees and the sex structure of tree stands in two insular pine forests in the south of Central Siberia are presented. It is noted that the ratio of sex types of pine trees has markedly changed since 1998–1999. Significant correlations between the sex structure of stands and anomalies of the annual average air temperature have been recorded since the early 1990s. The male generative sphere of pine has changed to the greatest extent. Periodicity and delay in the change of shoot sexualization in response to changes in temperature are discussed.