Effect of deleterious mutation-accumulation on the fitness of RNA bacteriophage MS2

Abstract.— RNA viruses show the highest mutation rate in nautre. It has been extensively demonstrated that, in the absence of purifying selection, RNA viruses accumulate deleterious mutations at a high rate. However, the parameters describing this accumulation are, in general, poorly understood. The present study reports evidences for fitness declines by the accumulation of deleterious mutations in the bacteriophage MS2. We estimated the rate of fitness decline to be as high as 16% per bottleneck transfer. In addition, our results agree with an additive model of fitness effects.     

Host-parasite local adaptation after experimental coevolution of Caenorhabditis elegans and its microparasite Bacillus thuringiensis

Coevolving hosts and parasites can adapt to their local antagonist. In studies on natural populations, the observation of local adaptation patterns is thus often taken as indirect evidence for coevolution. Based on this approach, coevolution was previously inferred from an overall pattern of either parasite or host local adaptation. Many studies, however, failed to detect such a pattern. One explanation is that the studied system was not subject to coevolution. Alternatively, coevolution occurred, but remained undetected because it took different routes in different populations. In some populations, it is the host that is locally adapted, whereas in others it is the parasite, leading to the absence of an overall local adaptation pattern. Here, we test for overall as well as population-specific patterns of local adaptation using experimentally coevolved populations of the nematode Caenorhabditis elegans and its bacterial microparasite Bacillus thuringiensis. Furthermore, we assessed the importance of random interaction effects using control populations that evolved in the absence of the respective antagonist. Our results demonstrate that experimental coevolution produces distinct local adaptation patterns in different replicate populations, including host, parasite or absence of local adaptation. Our study thus provides experimental evidence of the predictions of the geographical mosaic theory of coevolution, i.e. that the interaction between parasite and host varies across populations.     

8-OH-DPAT and MK-801 affect epileptic activity independently of vigilance

Vigilance and parallel occurrence of epileptic activity after administration of the 5-HT_1A agonist 8-OH-DPAT and the NMDA receptor antagonist MK-801 were studied in the genetic absence epilepsy model WAG/Rij rats. Spike-wave discharges (SWD) were present predominantly in passive awake and light slow wave sleep (SWS1) either in control animals or after treatments. Injection of 8-OH-DPAT (20.0 μg/rat i.c.v.) caused marked increase and MK-801 (10.0 μg/rat i.c.v.) decrease in SWD densities, thus the ratios of SWD in passive awake and in SWS1. SWD densities of MK-801 plus 8-OH-DPAT in combination were similar to those of CSF+CSF treated control rats. Both 8-OH-DPAT and MK-801 transiently increased the duration of active awake, increased latency and decreased duration of rapid eye movement (REM) sleep. 8-OH-DPAT increased the amount of SWD despite the decrease in the duration of SWS1. MK-801 decreased the amount of SWD despite the lack of significant change in duration of passive awake or SWS1. Pre-treatment with MK-801 reversed 8-OH-DPAT- induced increase in duration of SWD without any effect on 8-OH-DPAT-induced changes in sleep parameters. Our studies provide evidence that 8-OH-DPAT-induced epileptic activity is independent of its effect on sleep, and that interaction of serotonergic and glutamatergic systems plays a role in the generation of SWD, but not in the regulation of vigilance and sleep.     

盐酸洛拉曲克在体内、外对S-180细胞株的抗增殖作用

研究合合成新型胸苷合成酶抑制剂盐酸洛拉曲克在体内、外对S－180细胞株及正常人胚肾HEK293细胞的抗增殖作用;使用MTT法测定抑制率,以提高荷腹水瘤小鼠存活时间及荷实体瘤瘤重减轻情况为指标考察盐酸洛拉曲克对S－180所致肿瘤的治疗作用。结果表明：在体外盐酸洛拉曲克对S－180肿瘤细胞株有较强的细胞毒作用,对正常细胞HEK293抑制作用较弱（P＜0.05）;体内实验显示盐酸洛拉曲克可明显提高荷腹水瘤小鼠的存活时间,减轻荷实体瘤小鼠的瘤重,疗效与氟尿嘧啶（10mg/kg）相当（P＞0.05）或更好（P＜0.05）。可见,盐酸洛拉曲克在体内、外对S－180肿瘤细胞有显著的抗增殖作用,在体外对肿瘤细胞 具有选择性的抗增殖作用。     

Enhancement of Hydrocarbon Removal in a Clay and Drilling-Waste Polluted Soil

The application of biological processes in restoring oil polluted sites is growing due to their efficiency in removing different classes of pollutants. The aim of this study was to determine the ability of microorganisms present in a drilling-waste polluted soil (36,200 mg TPH kg^?1 soil) to remove weathered hydrocarbons under stimulated and non-stimulated soil conditions. The hypothesis under study was whether petroleum hydrocarbons removal could be enhanced by manipulating C/N ratio, water content and addition of three agroindustrial wastes. A Box-Behnken design was employed to evaluate the effect of each variable. Results demonstrated that, for orange peels and banana trunk treatments, the variable with the largest effect (p < 0.01) on hydrocarbon removal was the C/N ratio, indicating that higher ratio (100/3) improved removal (79.5–82%). The largest effect (p < 0.001) on hydrocarbon removal for pineapple wastes was observed with higher water content (60%) achieving the highest removal (89%). After 90 days of experimentation, the type of agricultural waste and the agricultural waste/soil ratio were not statistically significant in any treatment. However, their addition was important relative to non-stimulated soil, which showed a hydrocarbon removal of 17%. Data reported in this study showed the application of bioremediation in clay and drilling waste-polluted soils.     

Determining Immune System Suppression versus CNS Protection for Pharmacological Interventions in Autoimmune Demyelination

A major hallmark of the autoimmune demyelinating disease multiple sclerosis (MS) is immune cell infiltration into the brain and spinal cord resulting in myelin destruction, which not only slows conduction of nerve impulses, but causes axonal injury resulting in motor and cognitive decline. Current treatments for MS focus on attenuating immune cell infiltration into the central nervous system (CNS). These treatments decrease the number of relapses, improving quality of life, but do not completely eliminate relapses so long-term disability is not improved. Therefore, therapeutic agents that protect the CNS are warranted. In both animal models as well as human patients with MS, T cell entry into the CNS is generally considered the initiating inflammatory event. In order to assess if a drug protects the CNS, any potential effects on immune cell infiltration or proliferation in the periphery must be ruled out. This protocol describes how to determine whether CNS protection observed after drug intervention is a consequence of attenuating CNS-infiltrating immune cells or blocking death of CNS cells during inflammatory insults. The ability to examine MS treatments that are protective to the CNS during inflammatory insults is highly critical for the advancement of therapeutic strategies since current treatments reduce, but do not completely eliminate, relapses (i.e., immune cell infiltration), leaving the CNS vulnerable to degeneration.     

构建生物药物分析实验教学改革新模式

生物药物分析实验是生物药物分析理论课程的重要补充,是培养学生掌握和巩固理论知识以及实验操作技能的重要途径。为适应现代高等教育对本科生的培养要求,对生物药物分析原有单一的实验教学模式进行改革已势在必行。我学院生物药物分析实验教学改革从实验教学内容、实验教学方法、实验教学手段等方面进行实践探索,建立了"验证性-综合设计性实验教学"、"科研-实验教学相结合"、"开放式实验教学"等新型的实验教学模式,在近几年的本科实验教学活动中,对于培养学生的实际操作能力、独立分析问题和解决问题的能力,团队协作等方面的能力起到了明显的效果,受到学生好评。     

Hypoxic blackwater event severely impacts Murray crayfish (Euastacus armatus) populations in the Murray River,Australia

Prolonged flooding in 2010/11 ended a decade of drought and produced a large‐scale hypoxic blackwater event across the southern Murray‐Darling Basin, Australia. The hypoxic conditions caused fish kills and Murray crayfish Euastacus armatus to emerge from the water onto the river banks to avoid the poor water quality. This study examined the medium‐term impact of this blackwater event on Murray crayfish populations in the Murray River, where approximately 1800 km of the main channel were affected by hypoxia. Murray crayfish populations were surveyed in July 2012, along a 1100‐km section of the Murray River at 10 sites affected by hypoxic blackwater and six sites that were not affected, and data were compared with surveys of the same sites undertaken in July 2010, four months before the hypoxic blackwater event (before‐after‐control‐impact experimental design). Murray crayfish abundance in 2012 (post‐blackwater) was significantly lower at blackwater affected sites (81% reduction from 2010), but not at non‐affected sites. The hypoxic blackwater impacted Murray crayfish of both sexes and all size‐classes in a similar manner. The results demonstrate that prolonged periods of hypoxia can markedly impact populations of the long‐lived and slow‐growing Murray crayfish despite the species ability to emerge from hypoxic water. The findings highlight important challenges for the management of both the recreational fishery for this species and riverine flows in relation to hypoxic blackwater events.     

苹果全爪螨实验种群的密度效应研究

研究了苹果全爪螨实验种群的密度效应。实验结果表明：二斑叶螨卵期不存在密度效应;幼、若螨期间存在密度效应,幼、若螨密度与其成活率明显相关,幼、若螨初始密度的增加导致死亡率增加,并且当代性比向偏雌性方向发展,而子代性比向偏雄性方向发展;不同幼、若螨密度和成螨密度对成螨产卵量均有极显著差异。苹果叶片上螨口密度大于2．5～3．5头／cm^2时,扩散量明显增加。