Auditory evoked response: meaningfulness of stimuli and interhemispheric asymmetry

Interhemispheric asymmetries of different magnitudes were observed in human cortical auditory evoked responses to speech and sound-effect stimuli. The wave with peak asymmetry occurred 100 milliseconds after signal onset. The amount of asymmetry of the amplitude of this wave was related to the meaningfulness to the subject of the auditory stimulus rather than to the mere use of verbal versus nonverbal materials.     

Blood trehalose and flight metabolism in the blowfly

The concentration of trehalose in the blood of Phormia regina was found to determine the rate of energy expenditure during flight as reflected in measurements of the wing-beat frequency. Fat body was found to be the source of blood trehalose; either endogenous or exogenous substrates are used for its synthesis.     

城市景观水体污染分析及控制技术研究进展

对城市景观水体污染原因进行了分析,提出了外源污染控制与内源污染控制相结合的生物-生态修复技术。     

Differential cerebral processing of noise and verbal stimuli

Psychophysiological measurements have indicated that the right cerebral hemisphere processes noises and other nonverbal data and that the left cerebral hemisphere processes verbal material. Direct physiological measurements, as expressed in summated auditory evoked cortical responses, unequivocally demonstrate that click noises show a greater amplitude of initial output over the right brain, and that verbal stimuli produce either equal or higher amplitudes of output over the left cerebral hemisphere.     

利用核磁共振自由感应衰减曲线测定木材含水率

为定量测定木材含水率,以水分子中的质子为探针,利用核磁共振技术探究木材内部水分的变化情况。通过对胡桃木、红橡木和水曲柳解吸过程中,水分变化的核磁共振自由感应衰减曲线（FID）进行分析,发现木材的含水率与核磁共振的FID信号量高度线性相关,相关系数均超过0.99;因此,可以通过建立含水率与核磁共振FID信号的标准曲线实现木材含水率的核磁共振定量测量。同时,可以根据绝干木材的核磁共振FID信号量比较不同材种基本密度的大小。      

Evoked potential correlates of auditory signal detection

A long-latency comnponent of the averaged evoked potential recorded from the human scalp varied in close relationship with subjects' perceptual reports in an auditory signal detection task. Detected signals evoked potentials several times larger than did undetected signals, falsely reported signals, or correctly reported nonsignals. The threshold signal intensity at which detection perfornmance exceeded chance levels was identical with concurrently obtained electro-physiological measures of threshold.     

农业信息服务动力困境及路径选择

内源性动力和外生性动力构成了农业信息服务的动力系统,内源性动力是农业信息服务的基础,外生性动力是农业信息服务的推动力量。目前,农业信息服务的内源性动力需求强烈,外生性动力供给不足,必须建立供给与需求相适应的动力系统,才能保证农业信息服务的可持续发展。     

遗传转化过程中水稻愈伤组织的内源植物激素变化动态研究

 【目的】通过对遗传转化过程中水稻愈伤组织本身的3种内源激素含量变化动态研究，探讨水稻愈伤组织生长发育过程中内源激素变化规律和激素间的相互关系，旨在为水稻遗传转化体系中合理使用植物生长物质提供参考依据。【方法】以广粳1号、特青、V20B为遗传转化供试材料，采用高效液相色谱法（HPLC）测定了遗传转化过程中4个主要时期愈伤组织中的内源脱落酸（ABA）、生长素（IAA）和玉米素核苷（Z）的含量。【结果】IAA主要存在于种胚诱导出的愈伤组织上及芽中，且过高的IAA含量不利于愈伤组织的诱导和生长；Z主要存在于种胚中，对愈伤组织诱导的启动有决定性作用，如果外植体中的Z含量太低，即使有较高的IAA含量也不能诱导出愈伤组织；过高的ABA对愈伤组织的诱导不利，但在继代培养时适量升高ABA含量有利于胚性愈伤组织的形成。 【结论】内源激素对愈伤组织的生理状态有着极其重要的影响，其种类、含量及协调平衡是水稻愈伤组织形成和分化的关键。同时，诱导培养基中2,4-二氯苯氧乙酸(2,4-D)的浓度与水稻愈伤组织培养物中的培养力（愈伤组织质量，芽长和诱导率）有一定的相关性，且在培养基中加入2,4-D等生长调节剂类物质会对愈伤中的内源激素含量有一定的影响。     

Temperature effects on the peripheral auditory apparatus

Cooling with a thermoelectric cold probe, well localized in the region of the cochlea, produces a rapid, reversible decrease in the amplitude and increase in the latency of the action potential induced by clicks. These changes closely resemble those produced by reducing click intensity. Temperature also affects the amplitude of the cochlear microphonic, but the amount of change is considerably less than, and is poorly correlated with, the amplitlude change of the action potential. It is speculated that temperature may act on a hypothetical " excitatory process" in the cochlea, which comes after the cochlear microphonic in the sequence leading to production of the action potential of the auditory nerve.     

水稻丙二烯氧化物合成酶基因OsAOS1的表达研究

茉莉酸(Jasmonate,JA)为植物病虫害抗性反应中重要的信号分子,茉莉酸类物质生物合成途径中的关键酶为丙二烯氧化物合成酶(Allene oxide synthase,AOS)。已知水稻AOS基因家族包括4个成员,Os-AOS1～OsAOS4。已有研究表明,水稻OsAOS2基因的过量表达提高了内源PR1基因的表达、增强了水稻对稻瘟病的抗性。本研究分析了OsAOS1基因表达的组织和器官特异性以及外源JA处理对OsAOS1基因表达的影响,同时利用转基因技术研究了OsAOS1基因在调控内源PR1基因表达中的作用。研究结果表明:OsAOS1基因表达的组织和器官特异性不同于OsAOS2基因;外源JA处理诱导OsAOS1基因的瞬时表达,然而OsAOS2基因的诱导表达延迟;OsAOS1过量表达抑制烟草中内源PR1基因的表达。据此推测OsAOS1基因可能不参与依赖于PR1的抗病反应。     

NO在植物体内产生的途径及其作用

近年来的研究表明一氧化氮(nitric oxide,NO)是生物体内的重要的信号分子,参与多种生理功能的调控。文章主要介绍了在植物体内NO的产生途径、信号传导机制、与其他信号分子之间的相互作用及其与植物激素之间的作用。     

New findings on the congenital transmission of avian leukosis viruses

RAV-0, an endogenous avian leukosis virus, does not undergo congenital transmission in infected K28 chickens. In contrast, avian leukosis viruses of exogenous origin undergo highly efficient congenital transmission. The relative abilities of endogenous and exogenous viruses to undergo congenital transmission appear to be determined by the p27 capsid proteins of these viruses.     

Evoked potentials and auditory reaction time in monkeys

Monkeys with bipolar stimulating and recording electrodes in primary auditory cortex were trained to release a key to the onset of a pure tone. Substitution of direct cortical stimulation for the pure tone resulted in a reduction of 15 milliseconds In the latency of the behavioral response. This changed latency agreed with the latency of the primary evoked potential recorded from the animals. Systematic related changes in the amplitude of the central response and in the latency of the behavioral response followed changes in the intensity and frequency of the acoustic stimulus.     

Increase in salicylic Acid at the onset of systemic acquired resistance in cucumber

In an effort to identify the signal compound that mediates systemic acquired resistance (SAR), changes in the content of phloem sap were monitored in cucumber plants inoculated with either tobacco necrosis virus or the fungal pathogen Colletotrichum lagenarium. The concentration of a fluorescent metabolite was observed to increase transiently after inoculation, with a peak reached before SAR was detected. The compound was purified and identified by gas chromatography-mass spectrometry as salicylic acid, a known exogenous inducer of resistance. The data suggest that salicylic acid could function as the endogenous signal in the transmission of SAR in cucumber.     

内源激素和核酸与紫苏花芽生理分化关系

在干旱和弱光两种抑花处理条件下 ,对紫苏花芽生理分化期叶内核酸、内源激素含量变化进行了研究。结果显示 :激素间的比例或是平衡对包括核酸变化在内的整个花芽生理分化过程起着关键的调控作用     

生长素在烤烟库源关系改变时对烟株根系钾的影响

采用土培试验方法，研究内外源生长素在不同生长阶段缺钾或供钾条件下对烟株根系钾的影响。结果表明：缺钾胁迫下，外源生长素在不同地烟株根系积累钾有很大的促进作用，内源生长素在腰叶成熟前对烟株根系积累钾的能力有一定的稳定作用。供钾条件下，内外源生长素在不同生长阶段对烟株根系积累钾均有很大的促进作用，其促进作用比缺钾胁迫时大。且无论缺钾与否，外源生长素对烟株根系积累钾的促进作用大于内源生长素的作用。     

外源激素对甘蔗幼苗分化及其内源激素的影响

 报道了在甘蔗幼苗分化培养基中添加不同浓度配比的外源激素对绿苗分化及内源激素的影响。结果表明:外源激素对分化苗中的内源激素有促进或抑制作用,外源激素的添加对IAA,GA_1＋3产生不同程度的抑制作用,其中高比例的生长素/细胞分裂素对分化苗中的IAA抑制作用强,对GA_1＋3的抑制作用弱,而外源激素的添加对CTK产生促进作用,其中低比例的生长素/细胞分裂素对细胞分裂素的促进作用强。同时,在甘蔗愈伤组织分化幼苗过程中,合适配比及水平的外源激素添加有利于幼苗分化。     

外源ABA对小麦叶片中ABA含量的影响

对晋麦47进行外源ABA的处理,用酶联免疫固相抗原吸附法测定ABA的含量,研究了外源ABA对内源ABA含量的影响.结果表明,经过外源ABA处理的小麦较未处理的小麦叶片内的ABA含量明显增加.在同样环境下未处理的对照组叶片ABA含量为0.301 μg/g;经过处理的小麦叶片ABA含量为3.46 μg/g,内源ABA含量增加了3.16 μg/g,说明增加外源ABA可以大幅度提高小麦内源ABA的含量.     

Antigen bias in T cell cross-priming

Activated CD8+ T cells detect virally infected cells and tumor cells by recognition of major histocompatibility complex class I-bound peptides derived from degraded, endogenously produced proteins. In contrast, CD8+ T cell activation often occurs through interaction with specialized antigen-presenting cells displaying peptides acquired from an exogenous cellular source, a process termed cross-priming. Here, we observed a marked inefficiency in exogenous presentation of epitopes derived from signal sequences in mouse models. These data indicate that certain virus- and tumor-associated antigens may not be detected by CD8+ T cells because of impaired cross-priming. Such differences in the ability to cross-present antigens should form important considerations in vaccine design.     

Salicylic Acid: a likely endogenous signal in the resistance response of tobacco to viral infection

Some cultivars of tobacco are resistant to tobacco mosaic virus (TMV) and synthesize pathogenesis-related (PR) proteins upon infection. In a search for the signal or signals that induce resistance or PR genes, it was found that the endogenous salicylic acid levels in resistant, but not susceptible, cultivars increased at least 20-fold in infected leaves and 5-fold in uninfected leaves after TMV inoculation. Induction of PRl genes paralleled the rise in salicylic acid levels. Since earlier work has demonstrated that treatment with exogenous salicylic acid induces PR genes and resistance, these findings suggest that salicylic acid functions as the natural transduction signal.