Enzymatic synthesis of melatonin in avian pineal body: extraretinal response to light

In the chick pineal body, activity of the melatonin-forming enzyme hydroxyindole-O-methyl transferase is greater in the light than in darkness. Neither bilateral enucleation of the eyes nor sympathetic denervation prevented this light-induced elevation of enzyme activity. This fact indicates that in the bird, in contrast to mammals, neither the retinas nor sympathetic innervation of the pineal body are essential for environmental control of melatonin formation.     

环境生物安全的法治化应对

生物安全事件是诱发生态环境问题的重要隐患,加强生态生物安全管理,提升法治化水平,是应对环境生物安全的关键。我国环境生物安全法治化建设起步较早,外来入侵物种等领域法治化建设虽取得一定成效,但法治化水平仍有较大提升空间,需要加强技术研发与标准化建设,提高技术应对能力,并将成熟的技术措施和政策上升为法律制度。应系统梳理分散在各部门法中的相关法律规定,修改完善,编撰生物安全法典,将环境生物安全法治化推向更高水平。     

Crop photosynthetic response to light quality and light intensity

Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity. Among various abiotic factors affecting plant photosynthesis, light serves as an important factor that drives carbon metabolism in plants and supports life on earth. The two components of light(light quality and light intensity) greatly affect plant photosynthesis and other plant's morphological, physiological and biochemical parameters. The response of plants to different spectral radiations and intensities differs in various species and also depends on growing conditions. To date, much research has been conducted regarding how different spectral radiations of varying intensity can affect plant growth and development. This review is an effort to briefly summarize the available information on the effects of light components on various plant parameters such as stem and leaf morphology and anatomy, stomatal development, photosynthetic apparatus, pigment composition, reactive oxygen species(ROS) production, antioxidants, and hormone production.     

Brain polysomes: response to environmental stimulation

Polysomes have been isolated from rat brain and characterized by their appearance in the electron microscope and by their sedimentation in sucrose density gradients. Rats were isolated for 3 days in the dark and were then returned to the light for 15 minutes. The polysomes in brain, but not in liver, decreased in rats deprived of light and increased in those stimulated with light. These findings together with an increased capacity for protein synthesis in the brain in vitro and in vivo suggest that an increase in the activity of messenger RNA in the brain may result from environmental changes.     

Role for acetylcholine in mediating effects of light on reproduction

The length of day, or photoperiod, regulates the annual cycle of reproductive activity in the golden hamster. The inhibitory effects of a short-day photoperiod on testicular function were prevented by nighttime, but not daytime, intraventricular injections of carbachol, a cholinergic agonist. Short pulses of light during the night also block short-day induced testicular regression. The findings suggest that acetylcholine may play an important role in the mechanism through which information about the light-dark environment is transferred to the hypothalamic-pituitary-gonadal axis.     

Midbrain single units correlating with pupil response to light

The consensual response of the pupil in the cat was driven by means of a light flux impinging on the contralateral retina. Spike trains recorded extracellularly from single units in the midbrain show correlation with the concurrently recorded pupil area. The temporal dynamics found confirm two earlier studies of sinigle-unit responses and quantitative nerve stimulation. Both of these indicate that most of the 200-millisecond transport delay resides in the neuromuscular apparatus. Neurons whose activity correlated either with constriction with dilatation phases of Change in the pupil area were observed.     

叶用莴苣叶片对LED脉冲光的光合响应模型及光能利用

为探究LED脉冲光对作物光合特性的影响,探讨在不影响作物正常生长的前提下如何进一步降低能耗,提高照光效率,选用叶用莴苣（Lactuca sative L．）为试验材料,设置5个占空比水平（20%、40%、60%、80%和100%）和14个频率水平（1、2、4、8、16、32、64、128,256、512、1 024、2 048、4 096和8 192Hz）,共计70个处理,以连续光（占空比100%）为对照,探讨不同形式脉冲光对叶片净光合速率（Pn）的影响,并构建脉冲光占空比和频率与净光合速率之间的响应模型。通过对模型边际效应、交互作用以及光能利用率（LUE）的分析得出：占空比和频率都对Pn增长有促进作用,随着占空比和频率的增加,Pn也随之增加并最终趋于稳定状态直至与连续光处理的Pn无显著差异;占空比越高,叶用莴苣叶片的Pn达到饱和的频率越低;当Pn达到饱和状态时,脉冲光下的LUE要显著高于连续光。综上,占空比20%、频率512Hz为最佳占空比与脉冲光频率组合。该结果可为优化LED植物节能补光灯光源参数设计及研发提供理论支撑。     

Avian pineal gland: progonadotropic response in the Japanese quail

Pinealectomy in juvenile Japanese quail (Coturnix coturnix japonica) exposed to stimulatory photoperiods results in delay of ovarian and oviducal development and decreased pituitary weight. These effects are transitory and occur during a phase of growth immediately preceding the onset of sexual maturity. No effect was found in males. These results suggest that the pineal gland in females has a stimulatory effect on gonadal growth during maturation.     

红蓝光比例对弱光下黄瓜幼苗光合功能的影响

为了研究不同比例的红蓝光对弱光下黄瓜叶绿体超微结构和相关光合特性的影响,采用发光二极管(LED)调制不同红蓝光比例,以白光为对照,研究红光,蓝光,红光、蓝光配比7∶1和红光、蓝光配比1∶1对黄瓜功能叶的影响。结果显示,红光处理下类囊体膜的垛叠严重受挤压,基粒、基质片层毫无规则;最大光化学效率(Fv/Fm)、净光合速率(Pn)、气孔导度(Gs)最低。蓝光处理下叶绿素相对含量(SPAD值)和不平衡系数均最低。红光、蓝光配比1∶1处理下的比叶质量、Pn、Gs和光合性能指数(PIcsm)均最高。红光、蓝光配比7∶1和白光处理的Pn均显著大于蓝光,但Gs三者间无显著差异。进一步分析表明,弱光下,单纯红光导致黄瓜叶片光合功能失调,蓝光为光合机构高效运行所必须;红光、蓝光配比1∶1最有利于黄瓜幼苗叶绿体的发育和高光合速率的实现。     

Visual cortex neurons: response to stimuli during rapid eye movements

While awake, unanesthetized monkeys held their eyes stationary, a motionless or slowly moving stimulus falling on the receptive field of striate cortex neurons produced an excitatory response. When a rapid eye movement was made across the same stimulus, many of these neurons continued to give an excitatory response. But the discharge of other neurons was unchanged or was suppressed during the eye movement.     

Hormesis: a response to low environmental concentrations of petroleum hydrocarbons

Crab zoeae (Rhithropanopeus harrisii) were exposed to water-soluble fractions of jet fuel (JP5) for the first 5 days or for the duration of zoeal development (11 to 14 days). Short-term exposure or continuous exposure to low concentrations of petroleum hydrocarbons caused no increase in mortality or changes in development rate, and increased megalopal weight was characteristic of such groups. This phenomenon, termed "hormesis," is probably a generalized aspect of environmental stress etiology but has seldom been reported as such.     

不同光合光响应模型在雷公藤研究中的应用

应用非直角与直角双曲线模型、二项式回归方法及叶子飘光响应曲线模型拟合了雷公藤幼苗的测量数据.结果表明,雷公藤幼苗光合速率与光强之间存在非线性关系.叶子飘光响应曲线模型的拟合效果最佳,相关系数最大,模拟值与实测值最符合;利用该模型重新拟合出雷公藤幼苗的饱和光强为468.98μmol.m-2.s-1,最大光合速率为21.41μmol.m-2.s-1,这些数据与试验测量值较符合;其内禀量子效率为0.076,表观量子效率为0.069,在光补偿点处的量子效率为0.072.     

The unfolded protein response: from stress pathway to homeostatic regulation

The vast majority of proteins that a cell secretes or displays on its surface first enter the endoplasmic reticulum (ER), where they fold and assemble. Only properly assembled proteins advance from the ER to the cell surface. To ascertain fidelity in protein folding, cells regulate the protein-folding capacity in the ER according to need. The ER responds to the burden of unfolded proteins in its lumen (ER stress) by activating intracellular signal transduction pathways, collectively termed the unfolded protein response (UPR). Together, at least three mechanistically distinct branches of the UPR regulate the expression of numerous genes that maintain homeostasis in the ER or induce apoptosis if ER stress remains unmitigated. Recent advances shed light on mechanistic complexities and on the role of the UPR in numerous diseases.     

Adenosine 3'-5'-monophosphate in rat pineal gland: increase induced by light

Rats were maintained in alternating periods of 12 hours of light and 12 hours of darkness. The concentration of adenosine 3',5'-monophosphate in pineal gland was six times higher at the end of the light period than at the end of the period of darkness. This effect of light was abolished in blinded animals.     

Photosynthesis-associated gene families: differences in response to tissue-specific and environmental factors

The endogenous small subunit of the ribulose-1,5-bisphosphate carboxylase gene rbcS and the light-harvesting chlorophyll a/b-binding protein gene (LHCP) of pea are expressed in a light-inducible manner and are active mainly in green chloroplast-containing tissue. Chimeric genes under control of the 5'-flanking sequences of the rbcS ss3.6 or LHCP AB80 genes from pea were used to study the factors relating to the issue-specific and lightinducible expression of these nuclear-encoded genes in transgenic tobacco plants. The results show that plastid development plays a crucial role in the activation of expression of these chimeric genes. Particular members of each of the above gene families respond differently to tissue-specific and environmental factors. Furthermore, the light-inducible expression directed by the 5'-flanking sequence of ss3.6 rbcSgene is not exclusively mediated by phytochrome, but probably is controlledin large part by another photoreceptor.     

复羽叶栾树光合作用日变化及光响应特征

采用LI-6400便携式光合测定系统,测定贵州茅台酒厂生态功能区内复羽叶栾树光合作用日变化及光响应特征,并分析光合生理与生态因子之间的关系.结果表明:复羽叶栾树净光合速率(Pn)、光能利用率(LUE)的日变化均为单峰曲线,Pn和LUE的峰值分别出现在12:00和10:00左右;胞间二氧化碳浓度(Ci)的日变化与Pn相反,蒸腾速率(Tr)和气孔导度(Cond)的日变化均呈逐渐降低的趋势;Pn、Tr、LUE、Ci和Cond与主要环境因子光合有效辐射(PAR)、大气温度(Ta)和相对湿度(RH)之间的关系均符合二次曲线的变化规律,其中Pn、Tr与PAR、Ta、RH的相关程度均达极显著水平,Cond与PAR、Ta、RH的相关程度均达显著水平,LUE与PAR、Ta的相关程度均达极显著水平;PAR是影响复羽叶栾树Pn、Tr、Ci和Cond最主要的环境因子,LUE主要受Ta的影响.     

Heat generated by the dark-adapted squid retina in response to light pulses

A rapid increase in the temperature of the dark-adapted squid retina evoked by a brief light pulse was detected with a pyroelectric detector. The amount of heat generated by the retina in response to a pulse of blue light of moderate intensity was far greater than that produced by direct conversion of the stimulating light by the retinal pigments into thermal energy. D-Glucose in the medium was required to maintain the ability of the retina to produce light-evoked thermal responses.     

Visual evoked response correlates of unconscious mental processes

Average evoked responses and accompanying free associations elicited by subthreshold visual stimuli were studied to determine if a differential discrimination between two stimuli would be reflected in either or both of these responses. The results indicate that the effects of subliminal perception are encoded in the average evoked response and also influence the content of free associations.