砷对烤烟氮代谢的影响

采用盆栽试验,系统研究了砷对烤烟全生育期氮代谢的影响。结果表明,砷毒害对烤烟的氮代谢有显著影响。砷降低了整个生育期的硝酸还原酶(NR)活性,抑制了烤烟对硝态氮(NO₃^--N)的同化;提高了全生育期的谷氨酰胺合成酶(GS)活性,增强了烤烟对铵态氮(NH₄⁺-N)的同化。砷提高了全生育期的谷氨酸—丙酮酸转氨酶(GPT)活性和天冬酰胺酶(Asparaginase, ASG)活性,以及现蕾以后的游离氨基酸含量,使烤烟的氮转化代谢旺盛。与此同时,砷降低了烤烟生育前期的蛋白质含量,随着生育进程的推进,又引起中、后期的蛋白质含量增加,最终导致烤烟蛋白质的积累,但使整个生育期的烟碱含量降低。     

伊通河(长春市区段)沉积物重金属元素化学形态分布特征

对伊通河（长春市区段）沉积物中重金属元素的含量和形态的分布特征进行了研究。结果表明,重金属元素的总量呈现出沿河变化的趋势,且各重金属元素沿河变化程度有很大区别;沉积物中铁主要以残渣态存在,Mn、Pb、Cu、Zn元素残渣态含量很低,而有效态含量却很大（70%）,即伊通河沉积物中存在着潜在的重金属污染。沉积物中重金属在各形态的叠加也有所区别,Pb和Cu主要叠加在有机物态和残渣态中,而Zn则主要叠加在铁锰氧化物态中。     

Effect of SET7/9-mediated endoplasmic reticulum stress on arsenic-induced hepatocyte apoptosis

AIM:To investigate the effect of SET7/9 (SET domain containing 7/9)-mediated endoplasmic reticulum stress (ERS) on protein kinase R-like endoplasmic reticulum kinase (PERK) signaling pathway, and to explore the mechanisms of arsenic-induced hepatocyte apoptosis. METHODS:Human liver LO2 cells were divided into control group, arsenic poisoning model group, negative transfection group and SET7/9 siRNA transfection group. The apoptosis of the LO2 cells in each group was analyzed by flow cytometry. The protein levels of SET7/9, glucose-regulated protein 78 (GRP78), PERK and p-PERK in the LO2 cells of each group were observed by Western blot. RESULTS:Inhibition of SET7/9 expression reduced the apoptotic rate of arsenic-induced LO2 cells. Arsenic exposure increased the expression of SET7/9 in the LO2 cells. Arsenic exposure increased the protein levels of GRP78 and p-PERK in the LO2 cells, but decreased the protein levels of GRP78 and p-PERK after transfection with SET7/9 siRNA (P<0.05). CONCLUSION:Arsenic exposure induces hepatocyte apoptosis by increasing SET7/9 to activate ERS by PERK signaling pathway.     

Comparative ultrastructural studies onBesnoitia besnoiti andBesnoitia caprae

Comparative transmission electron microscopy onBesnoitia besnoiti and on a strain ofBesnoitia derived from goats in Kenya revealed that the two organisms differ in their pellicle, micropore, microtubules, nucleus, wall-forming body 1 (W1), amount of lipids and amylopectin. Thus the caprine besnoitia is probably a different organism and the termBesnoitia caprae should continue to be used.     

Is the ballan wrasse (Labrus bergylta) two species? Genetic analysis reveals within‐species divergence associated with plain and spotted morphotype frequencies

The ballan wrasse (Labrus bergylta) is a marine fish belonging to the family Labridae characterized by 2 main morphotypes that occur in sympatry: spotty and plain. Previous studies have revealed differences in their life‐history traits, such as growth and maturation; however, the genetic relationship between forms is presently unknown. Using 20 recently developed microsatellite markers, we conducted a genetic analysis of 41 and 48 spotty and plain ballan wrasse collected in Galicia (northwest Spain). The 2 morphotypes displayed highly significant genetic differences to each other (F_ST = 0.018, P < 0.0001). A similar degree of genetic differentiation (F_ST = 0.025, P < 0.0001) was shown using the STRUCTURE clustering approach with no priors at K = 2. In this case, the frequency of spotty and plain morphotypes was significantly different (χ² = 9.46, P = 0.002). It is concluded that there is significant genetic heterogeneity within this species, which appears to be highly associated with the spotty and plain forms, but not completely explained by them. Given the previously demonstrated biological differences between morphotypes, and the present genetic analyses, we speculate about the convenience of a taxonomic re‐evaluation of this species.     

An integrated Assessment of a group with complex systematics: the Iberomaghrebian lizard genus Podarcis (Squamata,Lacertidae)

A critical review of the evolutionary biology of Iberian and North African lizard members of the genus Podarcis (Lacertidae) based on phylogeny, phylogeography, morphometrics, behavior, ecology and physiology is presented. The Iberomaghrebian region is inhabited by at least 12 different evolutionary lineages that group into a monophyletic clade (except Podarcis muralis). In contrast to the current taxonomy, the saxicolous ‘Podarcis hispanica’ is paraphyletic with respect to Podarcis bocagei and Podarcis carbonelli, two currently recognized species. Nodes in the phylogenetic tree are deep, resulting from old divergences, clearly preceding the Pleistocene. Nevertheless, more recent range changes as a result of glaciations are also evident. The most plausible evolutionary scenario for this group indicates both vicariant and dispersal events. Although parapatry between lineages is the rule, sympatry and even syntopy are frequent, but usually between ground‐dwelling and saxicolous forms. Contacts between forms with similar habitat use are rare and local. Morphological distinctiveness between lineages has been demonstrated, indicating historical constraints. However, other characters have repeatedly evolved under similar environmental pressures independently of the evolutionary lineage. Strong sexual dimorphism derives from sexual selection and is attained before sexual maturity, although developmental restrictions exist. Variation between populations is also important and derives from local variation in both natural (habitat, climate) and sexual (density) selective pressures. Evidence for short‐term changes has already been found, particularly in insular populations. Reproductive isolation between syntopic forms and partner recognition are based on male—male competition and on visual and chemical recognition of females by conspecific males. Despite this ancient diversification, most forms maintain a degree of reproductive compatibility. Hybridisation may occur, but is limited, and there is evidence of selection against hybrids. The ecological analysis presented here does not support exploitative competition, but rather behavioral interference between forms. Ecomorph classification of lineages suggests character displacement between those with extensive range overlap. Finally, a critical assessment of the specific status of all lineages is provided and directions for further research are suggested.     

微波消解-原子荧光光谱法测定果汁中的痕量砷

建立微波消解-原子荧光光谱法测定果汁中痕量砷的方法。试验采用硝酸、过氧化氢微波消解样品，用体积分数为3％的盐酸作载流，质量浓度为10g／L的硼氢化钾作还原剂测定样品中的砷。对负高压、灯电流、载气流量、屏蔽气流量等进行考察并优化。结果显示：砷标准溶液在0—10．0μg／L质量浓度范围内与荧光强度值有良好的相关关系，相关系数为0．9998，标准物质测定值和标准值相吻合，加标回收率在90．9％～107．1％。该法具有低检出限、高精密度和良好的重现性等特点。     

Effects of arsenic trioxide on T-bet/GATA3 signal pathway in MRL/lpr mice

AIM: To investigate the effect of arsenic trioxide (ATO) on T-bet/GATA3 signal pathway in MRL/lpr mice.METHODS: MRL/lpr mice and C57BL/6J mice at the age of 20 weeks were chosen and then divided in 2 different sub-groups, respectively. The mice in 2 sub-groups received ATO (0.4 mg·kg^-1·d^-1) and sodium chloride (NS, volume weight-determined) by intraperitoneal injection respectively for 2 months. Afterward, the spleens were isolated from the MRL/lpr and C57BL/6J mice under pathogen-free condition and the suspensions were prepared. The mRNA level of T-bet, GATA3, IFN-γ,IL-4 and the mRNA ratio of T-bet/GATA3 were detected by RT-qPCR. The protein expression of T-bet and GATA3 was determined by Western blot. The serum levels of IFN-γ and IL-4 were measured by ELISA.RESULTS: The mRNA and protein levels of T-bet, IFN-γ and the mRNA ratio of T-bet/GATA3 in NS group of MRL/lpr mice were higher than those in NS group of C57BL/6J mice (P<0.05). However, the GATA3 and IL-4 were lower in NS group of MRL/lpr mice in both mRNA and protein level (P<0.05). In MRL/lpr mice, the mRNA and protein levels of T-bet, IFN-γ and the mRNA ratio of T-bet/GATA3 were lower in ATO group compared with NS group (P<0.05), no difference was found in GATA3 and IL-4. No difference of the indexes mentioned above between ATO group and NS group in C57BL/6J mice was observed.CONCLUSION: ATO may affect the signaling pathway of T-bet/GATA3 to down-regulate the mRNA expression and the protein secretion of IFN-γ by decreasing the expression of T-bet in MRL/lpr mice.     

砷胁迫对生菜种子萌发和幼苗细胞膜透性的影响

研究不同砷胁迫对生菜种子萌发、幼苗生长和幼苗细胞膜透性的影响.结果表明:低浓度砷对生菜种子的发芽势、发芽率、发芽指数、芽长和幼苗干重具有激活效应,而对种子的活力指数和幼苗根长具有抑制效应,高浓度砷对生菜种子的萌发和幼苗生长有显著的抑制效应,且随着砷胁迫的增强,抑制作用增强,同时,随着砷胁迫的增强,幼苗的细胞膜透性增加,选择通透的能力下降.