Complementary RNA in nucleus and cytoplasm of mouse liver cells

The rapidly labeled RNA from both the nuclei and cytoplasm of mouse liver cells can be bound specifically to mouse DNA. The bound fraction differs in base composition and metabolic stability from the bulk RNA. There is considerable cross reaction between this RNA and the DNA obtained from calf thymus.     

Feedback connections to the lateral geniculate nucleus and cortical response properties

The cerebral cortex receives sensory input from the periphery by means of thalamic relay nuclei, but the flow of information goes both ways. Each cortical area sends a reciprocal projection back to the thalamus. In the visual system, the synaptic relations that govern the influence of thalamic afferents on orientation selectivity in the cortex have been studied extensively. It now appears that the connectivity of the corticofugal feedback pathway is also fundamentally linked to the orientation preference of the cortical cells involved.     

低温菌强化堆肥起爆进程中细菌群落响应机制

为探讨低温菌强化冬季堆肥起爆细菌群落响应机制,确保北方冬季有机垃圾堆肥的快速启动,开展低温菌强化畜禽粪便堆肥快速起爆试验,结合16S rRNA扩增子测序技术及生物信息学分析方法,明确堆体温度、微生境因子及微生物特性等指标变化,挖掘生物强化低温菌在畜禽粪便堆肥起爆进程中的作用,探明堆肥进程细菌群落响应机制。结果表明：接种低温菌处理（CT）的堆体温度在18 h时迅速升高至20.0℃,快速通过起爆期,此时未接菌（CK）组的温度仅为15.8℃。CT组温度在36 h超过50.0℃。整个过程中未接种低温菌的处理组并没有完成堆肥快速启动。CT组有机组分快速分解,为堆肥温度升高提供了充足的热能。由群落丰度变化可知,低温菌属于促进细菌群落改变的生物标志物（Biomarker）,接种低温菌可激活堆肥起爆进程中细菌群落结构的演变。此外,方差分解分析结果表明,低温菌、理化指标及细菌群落的交互作用是堆肥温度变化的主导因素,可通过增加低温菌丰度调控堆肥起爆进程中的温度变化。     

小麦抗条锈病过敏性坏死反应中的活性氧代谢

【目的】探讨活性氧在植物抗病菌侵染反应中的作用。【方法】以小麦洛夫林13为供试植物,条锈病菌单孢菌系CY23-2、CY25-8和CY29-3为供试病菌,从小麦与条锈病菌之间典型的过敏性坏死反应(HR)中,探讨活性氧的积累、保护酶系活性变化和原生质膜的透性改变与过敏性坏死反应(HR)的关系。【结果】不亲和条锈病菌CY23-2和CY25-8侵染可引起小麦叶片内2个活性氧的积累高峰,分别出现在接种后第2天和接种后第5～6天。亲和条锈病菌CY29-3的侵染只引起1个活性氧积累高峰,出现时间与不亲和互作的第2个活性氧高峰期一致。不亲和互作中,小麦叶片上产生过敏性坏死反应只出现在第1次活性氧突增之后,表明第1次活性氧突增与HR的产生有关;伴随着小麦叶片中强度极高活性氧的突增,叶片细胞原生质膜遭到破坏,细胞内物质外渗,细胞不久死亡。表明高强度活性氧突增会导致细胞的死亡;对2种互作体系中可清除活性氧的酶系(超氧化物歧化酶、过氧化氢酶、过氧化物酶)活性分析可知,接种后第2天活性氧突增的主要成分是H2O2,接种后第6天活性氧突增的主要成分是O2.-。【结论】H2O2是HR发生的主要信号物,超氧阴离子O2-.等在细胞死亡中起着关键的作用。     

Stimulation of abducens nucleus supports classical conditioning of the nictitating membrane response

The acquisition and terminal performance of a classical conditioning group compared with a control group indicated that extension of the nictitating membrane elicited by direct electrical stimulation of the abducens nucleus was successfully conditioned to a previously neutral stimulus. The conditioning so obtained was associative and not due to such nonassociative factors as sensitization, pseudo-conditioning, or alteration in base-rate responding.     

Long-term modulation of electrical synapses in the mammalian thalamus

Electrical synapses are common between inhibitory neurons in the mammalian thalamus and neocortex. Synaptic modulation, which allows flexibility of communication between neurons, has been studied extensively at chemical synapses, but modulation of electrical synapses in the mammalian brain has barely been examined. We found that the activation of metabotropic glutamate receptors, via endogenous neurotransmitter or by agonist, causes long-term reduction of electrical synapse strength between the inhibitory neurons of the rat thalamic reticular nucleus.     

模糊数学评价与响应面结合优化老北京豆汁儿的发酵工艺

以感官评价为指标,通过响应面试验对豆汁儿的发酵工艺参数进行筛选,为克服感官评分法主观性和片面性对结果的影响,利用模糊数学进行进一步验证分析。通过豆汁儿发酵对其菌种进行16S rDNA鉴定,结果表明豆汁儿中存在粪肠球菌分离株(Enterococcus Faecium isolate);豆汁儿发酵最佳工艺参数为:发酵时间24 h、发酵温度37℃和液料比为8:1 g·g~(-1)。     

天山北坡家庭牧场复合系统对极端气候的响应过程

在草原牧区,家庭牧场作为取代游牧制度而产生的新生事物,其对极端气候响应过程的研究尚未见报道。以"极端气候敏感性-影响途径-响应方式"为分析框架,基于问卷调查方法,研究了天山北坡山地草原牧民对极端气候的响应过程。结果表明:1)天山北坡1980-2009年冬季雪灾、秋季旱灾风险趋于增大,家庭牧场草料储备不足、畜种结构经济驱动型增加了对极端气候的敏感性;2)旱灾、雪灾是影响家庭牧场的主要极端气候类型,其作用介质为牲畜和草场;3)自适应与外力适应是牧户响应极端气候的2种主要形式,其中购买草料是最主要的响应策略;4)通过Probit模型估计显示,极端气候认知、家庭特征、资产状况与牧户间适应行为选择有显著的关系。研究认为,家庭牧场对极端气候短期响应的反馈过程主要围绕草、畜2因子展开,基于降水波动的周期性,牧户长期响应形成了家庭牧场生产周期。     

斑马鱼个体发育过程中的溶菌酶表达模式及其对LPS处理的应答

收集斑马鱼成鱼和不同发育阶段幼鱼,用LPS处理后提取总RNA,经反转录制备cDNA并检测溶菌酶的基因表达水平,利用实时定量PCR技术研究了斑马鱼个体发育过程中溶菌酶的表达模式及其对LPS处理的应答方式.结果表明:成鱼体内溶菌酶基因表达水平显著高于各发育阶段幼鱼,而且LPS处理成鱼后溶菌酶表达水平呈现出先降低后升高的应答模式.在对照组幼鱼的不同发育阶段,溶菌酶基因表达水平变化不大.在个体发育早期(3d和7d),LPS处理可引起溶菌酶表达水平持续降低.14d和21d幼鱼中溶菌酶表达水平都在LPS处理后3h开始降低,并在6h开始回升,其中21d幼鱼回升到显著高于对照组的水平,表明溶菌酶已表现出对外界刺激作出有效应答的能力.另外,28d幼鱼受LPS处理后溶菌酶基因表达的变化趋势与成鱼相似,均为先降低后升高.以上结果说明,溶菌酶在斑马鱼个体发育到21d时可对外界刺激作出有效应答,在28d时则可能发育成熟.     

应用响应面法优化金丝桃素的纯化工艺

在单因素试验的基础上,根据中心组合试验设计原理,选择上柱液中金丝桃素的浓度、洗脱液中乙醇的浓度和洗脱液用量为考察因素,以产物中金丝桃素含量为响应值,采用3因素5水平的响应面分析法对NKA-9型大孔树脂分离纯化贯叶连翘中金丝桃素的工艺条件及参数进行优化.结果表明:金丝桃素的最佳纯化工艺条件为上柱液中金丝桃素的浓度37.6...     

Gatekeepers of the nucleus

Nuclear pore complexes (NPCs) form the site for entry and exit from the nucleus. A convergence of studies have defined the physical framework for the nuclear transport mechanism. This includes definition of the soluble transport machinery required for protein and RNA movement, x-ray structure analysis of transport factors, definitive compositional analysis of yeast NPCs, and documentation of the relative steady state arrangement of NPC components within the portal. With this information, researchers are now in the exciting position to examine the dynamic interplay between shuttling transport factors and the static pore complex.     

运用响应面法优化芦苇基生物炭活化工艺

为优化芦苇基生物炭制备工艺,在单因素试验考察热解温度、氨水质量分数和浸渍比(生物质原料与氨水质量之比)等3种参数对芦苇基生物炭吸附性能影响的基础上,利用Box-Benhnken中心组合设计实验,运用响应面法对其活化工艺参数进行优化。结果表明,3个因素均对生物质炭的比表面积产生影响,其影响显著性大小为热解温度氨水质量分数浸渍比。通过模型优化确定了最佳活化工艺参数为热解温度620℃、氨水质量分数8%、浸渍比1∶5;该工艺条件下制备的生物炭比表面积和碘吸附值分别为334.49 m~2/g、585.52 mg/g,均优于未进行优化改性的样品。该值与理论值(335.2 m~2/g、582.288 mg/g)基本相符,表明响应面模型与实际情况拟合良好,验证了模型的有效可行性。     

Estimating the rock volume bias in paleobiodiversity studies

To interpret changes in biodiversity through geological time, it is necessary first to correct for biases in sampling effort related to variations in the exposure of rocks and recovery of fossils with age. Data from New Zealand indicate that outcrop area is likely to be a reliable proxy of rock volume in both stable cratonic regions, where the paleobiodiversity record is strongly correlated with relative sea level, and on tectonically active margins. In contrast, another potential proxy, the number of rock formations, is a poor predictor of outcrop area or sampling effort in the New Zealand case.     

能量互补型温室病虫害调查

能量互补型温室是近年来兴起的一种新型温室,于2013年在山西农业大学农作站对以番茄为主栽品种的该型温室内温湿度条件和病虫害进行了调查。结果表明,主要病虫害包括低温障碍、番茄晚疫病、番茄早疫病、番茄叶霉病、南美斑潜蝇、温室白粉虱;病害在定植3个月后出现发病高峰;虫害的发生随着区域分布而变化;经过综合防治,可以减少害虫危害,并将病害的病情指数控制在20.0%以下。调查结果有助于明确该型温室内部环境因素对病虫害发生发展的影响,并为该型温室的合理使用提供数据支持。     

关于平方补函数SSC(n)的两个问题*

 Smarandache平方补函数SSC(n)是定义在正整数集上的函数。对任意的正整数n,其函数值SSC(n)=m,这里m是使得mn是完全平方数的最小正整数。本文的主要目的是通过通过初等及解析的方法研究lnS-SC(n)的值的分布性质从而将RUSSO提出的两个极限问题彻底解决。