Induction of cytochrome P450 1A and DNA damage in isolated rainbow trout (Oncorhynchus mykiss) hepatocytes by 2,3,7,8 tetrachlorodibenzo-p-dioxin

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on hepatocytes isolated from immature rainbow trout (Oncorhynchus mykiss) by collagenase perfusion were investigated with respect to induction of cytochrome P450 1A (CYP1A) enzyme activities and protein contents as well as DNA damage. Exposure of primary rainbow trout hepatocytes to TCDD resulted in increased CYP1A contents, as determined by immunoblotting, enhanced activities of 7-ethoxyresorufin-O-deethylase (EROD) and increased DNA damage as determined by the comet assay. By means of electron microscopy, no symptoms of cytotoxicity could be observed except for slight increases of lysosomal components and the smooth endoplasmic reticulum. Whereas CYP1A contents constantly increased over the duration of the entire experiment, EROD activities remained constant from day 3 of exposure to 1 nM TCDD; maximum induction of CYP1A activities was reached with 0.1 nM TCDD after 5 days. DNA damage increased in a time- and dose-dependent fashion until day 3. After 5 days, DNA damage was less pronounced, and the number of damaged nuclei declined in all TCDD concentrations. Since TCDD has been shown to not directly react with DNA, metabolism of TCDD or TCDD-induced changes in other metabolic pathways are suspected to result in the production of DNA-reactive (endogenous) substances.     

The spatial pattern of soil-dwelling termites in primary and logged forest in Sabah, Malaysia

Abstract.  1. Primary and logged lowland dipterocarp forest sites were sampled for subterranean termites using soil pits located on a grid system in order to detect any patchiness in their distribution.
2. A spatial pattern in termite distributions was observed in the primary and logged sites, but the response differed between soil-feeding and non-soil-feeding termites.
3. Spatial analysis showed that soil-feeding termites were homogeneously distributed in the primary forest but significantly aggregated in the logged forest. This pattern was reversed for non-soil-feeding termites and may result from differences in resource provisioning between the two sites.
4. Gaps in termite distribution comprised a greater area than patches for both feeding groups and sites, but gaps dominated the logged site.
5. A significant association between soil-feeding and non-soil-feeding termite distributions occurred at both sites. This arose from an association between patches in the primary forest and between gaps in the logged forest.
6. Termite spatial pattern was optimally observed at a minimum extent of 64 m and lag of 2 m.
7. The spatially explicit SADIE (Spatial Analysis by Distances IndicEs) analyses were more successful than (non-spatially explicit) multivariate analysis (Canonical Correspondence Analysis) at detecting associations between termite spatial distributions and that of other biotic and abiotic variables.     

铜离子胁迫对两种地衣细胞结构的影响

采用光学显微镜徒手切片技术和透射电子显微镜超薄切片制备技术,以两种叶状地衣即中国树花(Ramalina sinensis)和地卷(Peltigera rufescens)为实验材料,研究了不同浓度CuSO4(0、1、2、3、4mmol/L)处理24h后地衣体细胞的存活率以及Cu2+胁迫对细胞超微结构的影响。结果显示:(1)光学显微镜下可初步确定,Cu2+浓度越大中国树花共生藻细胞存活率越小,而同样处理条件下地卷共生藻细胞的存活率则基本保持不变。(2)低浓度Cu2+(1mmol/L)对中国树花细胞结构基本无影响,细胞壁、细胞膜及细胞内的线粒体、叶绿体完整;随着Cu2+浓度增加,当处理Cu2+浓度为2mmol/L时,细胞壁无损,但细胞膜开始破坏形成小空泡,线粒体嵴变凌乱,叶绿体也出现皱缩,类囊体膨胀,基粒排列紊乱;当Cu2+处理浓度大于2mmol/L时,共生藻的细胞膜和细胞器出现不同程度的损伤;当Cu2+浓度为3mmol/L时,细胞壁变薄,细胞膜形成的空泡变大,细胞内部结构变松散,蛋白核消失,叶绿体与细胞质混在一起,基粒片层扭曲,分布混乱,线粒体变形;当Cu2+浓度达4mmol/L时,细胞结构完全受到破坏。(3)不同浓度Cu2+处理对地卷共生藻细胞结构无明显的影响,在所有处理条件下地卷共生藻细胞壁、细胞膜都完整,且大多数共生藻细胞处于分裂状态。研究认为,中国树花对Cu2+胁迫较敏感,Cu2+耐受在1~2mmol/L之间,Cu2+浓度与中国树花细胞结构的损伤程度存在着明显的剂量效应关系,Cu2+浓度越高,其属于共球藻的真核共生藻细胞受损程度越大;地卷对Cu2+胁迫具有一定的耐性,Cu2+胁迫下地卷属于蓝藻的原核共生藻细胞仍能繁殖分裂产生子代细胞。     

新疆蒙古族对糖精和乙酰水杨酸尝味能力的分析

对710名（男328人,女382人）新疆蒙古族进行了糖精和乙酰水杨酸尝味能力的检测分析。结果表明,蒙古人群中的糖精味盲率为4.648%,没有尝味能力的隐性基因频率为0.2156,具有尝味能力的显性基因频率为0.7844,平均尝味阈值为8.009±1.34（0.108mol/L）。乙酰水杨酸的尝味阈值分布出现了非常明显的双峰一谷分布,表明该性状是单基因决定的性状,谷底7号液（3.00×10-4 mol/L）是味盲的界限,味盲的峰值在1号液(1.7×10-2mol/L),尝味者的峰值在11号液（1.25×10-5mol/L）,味盲率为90.282%,。经χ2检验,男、女性的味盲率无显著差异（P＞0.90）,表明决定乙酰水杨酸尝味能力的基因位于常染色体,对该基因的显隐性等特点尚需通过家系分析进行确定。 Abstract:The saccharin and aspirin tasting abilities have been detected and analyzed in 710 individuals (328men,382women)of Xinjiang Mongol.It is showed that the saccharin taste- blindness ratio among Mongolians was 4.648%,frequency of the recessive gene determining taste-blindness and the dominant gene determining taste ability was 0.2156,and 0.7844 respectively,and its mean testable threshold was 8.00±1.34 (0.108mol/L).Distribution of aspirin tasting threshold appeared a distinct curve with double peaks and single bottom,and demonstrated the aspirin tasting ability was a monogenic character.Solution NO.7 (3.00×10-4mol/L) at the bottom in the curve was the boundary of taste-blindness.The peak of taste-blindness was at the solution NO.1 (1.7×10-2mol/L),and the peak of tasters was at the solution NO.11 (1.25×10-5mol/L),The ratio of aspirin taste-blindness was 90.28%.The χ2 test has been used to evaluate the statistical difference in aspirin taste-blindness ratio between male and female,the result showed that there was no significant difference (P＞0.90),and the gene determining for aspirin tasting ability located on autosomes.     

Ovipositor internal microsculpture in the Braconidae (Insecta, Hymenoptera)

Variation in the microsculpture of the ovipositor egg canal, the morphology of the tip of the upper valve, the structure of the valvillus and the apex of the lower valve seals, as revealed by scanning electron microscopy is described for members of 52 genera representing 30 subfamilies of Braconidae. The possible phylogenetic implications of this variation are discussed. Characters supporting monophyly of the cyclostome clade, and of the non-cyclostome subfamilies Agathidinae, Pselaphaninae and Sigalphinae are reported. Functional and phylogenetic implications are discussed and possible convergent evolution of some features associated with endoparasitism are considered in the light of recent molecular systematics findings. © 1998 The Norwegian Academy of Science and Letters     

Large scale of identification of differentially expressed genes in the regenerating rat liver after SISPH

After partial hepatectomy (PH), the remnant paren-chyma can completely recover lost liver mass and function in about one week[1,2]. Although adult hepa-tocytes are normally quiescent, they are readily primed to pass from G0 to G1 phase within 2―6 h after PH. The first peak of DNA synthesis appears 24 h after PH, while cell division peaks at 36 h. The liver cells then enter a second cell cycle, and redifferentiation and reconstruction of structure and function[3―6] take place. A great nu…     

Genetic controls on starch amylose content in wheat and rice grains

Starch accumulates in plants as granules in chloroplasts of source organs such as leaves (transitory starch) or in amyloplasts of sink organs such as seeds, tubers and roots (storage starch). Starch is composed of two types of glucose polymers: the essentially linear polymer amylose and highly branched amylopectin. The amylose content of wheat and rice seeds is an important quality trait, affecting the nutritional and sensory quality of two of the world’s most important crops. In this review, we focus on the relationship between amylose biosynthesis and the structure, physical behaviour and functionality of wheat and rice grains. We briefly describe the structure and composition of starch and then in more detail describe what is known about the mechanism of amylose synthesis and how the amount of amylose in starch might be controlled. This more specifically includes analysis of GBSS alleles, the relationship between waxy allelic forms and amylose, and related quantitative trait loci. Finally, different methods for increasing or lowering amylose content are evaluated.     

Ovipositor internal microsculpture and other features in doryctine wasps (Insecta, Hymenoptera, Braconidae)

Detailed ovipositor morphology has been investigated in representatives of 81 of the more than 120 genera of the parasitic wasp subfamily Doryctinae. Potentially phylogenetically informative variation was found in the microsculpture of the egg canal wall and the presence and degree of development of the valvillus. In all the genera, a socketed seta arises from below each member of the line of ctenidia (comb-like scales) distal to the valvillus (or valvillar region). These subctenidial setae are modified in two groups of genera. In the Holcobraconini (= Odontobraconini) together with the genera Acanthodoryctes, Binarea, Monarea , and Liobrucon , the setae are extremely flattened producing overlapping leaflet-like structures. In some of these, groups of leaflets are further modified to form fans that protrude into the egg canal. In Schlettereriella and Leptospathius the basal seta is highly branched and rather flattened and may serve a similar function to the valvillus which in these two genera is extremely reduced. In Doryctes and Neodoryctes , there is a distinctive type of bar-like sculpture anterior to the valvillus and a single large crescentic bar posterior to the valvillus. These modifications are suggested as possible synapomorphies (in lieu of an analysis) for their respective groups of genera. Several other characters are also described and illustrated. CO 1998 The Norwegian Academy of Science and Letters     

The oldest cinctan carpoid (stem‐group Echinodermata), and the evolution of the water vascular system

A new cinctan ( Protocinctus mansillaensis gen. et sp. nov. ), from the early Middle Cambrian of the Iberian Chains (north‐east Spain), is described with the aid of X‐ray microtomography and three‐dimensional computer models. Investigation in this manner was possible because of the unusual condition of the fossils, which are preserved as recrystallized calcite. Protocinctus gen nov. possesses an elongate body with a single left anterior feeding groove and an open posterior marginal frame (in ventral view): this combination of characters is unique amongst cinctans. Through the study of original specimens and ‘virtual fossils’ it was possible to reconstruct the palaeobiology of Protocinctus gen. nov. : cinctans are interpreted as pharyngeal basket feeders with a U‐shaped gut, using their posterior appendage to aid stability on the sediment surface. Cinctans are critical to understanding the evolutionary history of the echinoderm stem group, as they illustrate the transition from a paired water vascular system (basal) to one constructed from just the left hydrocoel (derived). The former condition is also observed in another group of stem‐group echinoderms, the ctenocystoids, and is hypothesized for the latest common ancestor of the echinoderms and hemichordates.