Superior colliculus cell responses related to eye movements in awake monkeys

Single cell responses were recorded from the superior colliculus of awake monkeys trained to move their eyes. A class of cells that discharged before eye movements was found in the intermediate and deep layers of the colliculus. The response of the cells was most vigorous before saccadic eye movements within a particular range of directions. These cells had no visual receptive fields, and visually guided eye movements were not necessary for their discharge, since they responded in total darkness before spontaneous eye movements and vestibular nystagmus.     

Optics of arthropod compound eye

The extent to which light can escape from one ommatidium into its neighbors in the compound eye has been examined by recording from single receptors during stimulation of single facets. In the "apposition" eye of the drone honeybee and locust, optical interaction is extremely small. In the "superposition" eye of the crayfish, more than half the light captured by the average cell gets in through neighboring facets, even when screening pigments are in the fully lightadapted position.     

Newts: sun-compass orientation

Rough-skinned newts, captured from breeding ponds, oriented on courses that would have intersected the familiar shorelines at right angles, when released in a circular arena on land under the sun or moon. Pondward migrants oriented similarly. Reorientation failed under complete cloud cover and after 7 days of darkness in an environmental chamber, but persisted in newts whose eyes were excised and in those displaced more than 27 kilometers in darkness. Both normal and blind animals compensated for displacement in sunshine. Preliminary evidence suggests that alternative light receptors in blinded animals may be associated with the optic tectum. No evidence of olfactory guidance was observed.     

Neuronal correlates of eye movements in the visual cortex of the cat

About 10 percent of the cells in the visual cortex of awake cats do not respond to stationary parallel stripes in any orientation or to stripes moving across the visual field in any direction at a moderate speed (up to 132 degrees per second), but these cells are either excited or inhibited during saccadic eye movements when the animal faces a patterned visual environment. Of nineteen such cells tested in total darkness, seven discharged in association with eye movements. For saccade-related discharges, the latency during retinal stimulation is typically shorter than the latencey in total darkness.     

Suppressing drosophila circadian rhythm with dim light

Drosophila larvae were reared and allowed to pupate in continuous bright white light. The pupae were then transferred to a much dimmer blue light. In continuous blue light of intensity below 0.001 erg per square centimeter per second, adult flies emerged in pulses 24.7 hours apart, each pulse occupying about 6 hours. But in continuous light of intensity exceeding 0.1 erg per square centimeter per second, they emerged at a steady rate. This intensity range from effective darkness to effective light is roughly from starlight to moonlight. Inside this range, the emergence peaks broaden for about a week with little change of period.     

烤烟蛙眼病病原菌的分离鉴定与生物学特性

【目的】明确贵州烤烟蛙眼病病原菌种类及生物学特性,为烤烟蛙眼病的综合防治提供科学依据。【方法】以采集自贵州烟区的烤烟蛙眼病病叶为材料,采用常规组织分离法和离体叶片接种法进行病原菌分离及致病性测定,利用形态学特征和分子生物学方法对病原菌进行种类鉴定,并对典型菌株进行生物学特性测定。【结果】从采集的病叶样本中共分离获得11株菌株,选取具有代表性的3株菌株YC1110、YC1111和YC1112接种到健康烤烟叶片上,接种6 d后出现典型症状,与田间症状一致,证明3株菌株为烤烟蛙眼病病原菌。ITS序列及系统发育分析表明,供试3株菌株与烟草尾孢（Cercospora nicotianae）的遗传关系很近,且菌落及孢子等形态特征亦符合烟草尾孢。生物学特性测定结果显示,病原菌在25℃、pH 7、光照条件为24 h全黑暗、碳氮源分别为果糖和牛肉浸粉、培养基为番茄琼脂培养基（TA2）时产孢量最多;在25℃、pH 7、碳氮源分别为甘露醇和蛋白胨、培养基为胡萝卜琼脂培养基（CA）和烟叶煎汁琼脂培养基（TA1）时生长最快。病原菌菌丝致死温度为54℃水浴10 min。【结论】引起贵州烤烟蛙眼病的病原菌为烟草尾孢。     

超低温保存对苦槠种子和离体胚脱氢酶活性的影响

将苦槠种子、离体胚及离体胚防冻剂处理后用液氮(LN2)进行超低温保存,测定种胚内三苯基甲月s质量浓度,研究其超低温保存效果。结果表明:苦槠离体胚防冻剂处理的三苯基甲月s质量浓度最高,脱氢酶活性最大,其次是离体胚,最小的是种子。3种保存材料的保存效果均受含水量水平显著影响,而当离体胚含水量小于10%时,冷解冻方式对LN2保存效果不明显。对种子而言,12%-15%含水量是适宜的保存含水量,采用缓冻快解,三苯基甲月s质量浓度高,分别是24.93、27.43μg.mL-1;对离体胚而言,10%-15%的含水量是适宜的,但12%含水量水平保存效果最好。添加防冻剂处理后,15%-20%含水量离体胚的三苯基甲月s质量浓度最高,分别达36.98、31.58μg.mL-1;防冻剂在LN2保存过程中起到了明显的保护作用,用10%二甲亚砜处理效果最好。     

不同培养诱导条件对试管薯休眠期的影响

采用一步法进行试管薯的诱导,不更换培养基,不添加任何外源激素,研究试管苗培养阶段光照周期、光照强度、温度以及诱导阶段光照长度对“Favorita”、“Atlantic”和“克新1号”3个马铃薯品种试管薯休眠期的影响。结果表明,试管苗培养阶段光照强度对试管薯的休眠期无显著影响,而随着培养阶段光照长度的增加,试管薯的休眠期逐渐延长;试管苗培养阶段温度越高试管薯的休眠期则明显缩短;试管薯诱导阶段,黑暗诱导时间越长,试管薯的休眠期则越长。     

Compound eyes: localization of two color receptors in the same ommatidium

The compound eye of the cockroach Periplaneta has receptors for ultraviolet light (maximum sensitivity at 365 nanometers) and green light (maximum sensitivity at 510 nanometers). Single photoreceptor cells in the compound eye were impaled, identified by spectral response, and marked with dye-filled microelectrodes. Using two diferent dyes, we showed that both types of receptors can be found in the same ommatidium.     

比目鱼类的眼睛移位和不对称的进化起源

比目鱼类外形不对称产生的机制引起人们兴趣已逾一个多世纪。从比目鱼类(鲽形目)的类群和分布、变态过程中眼睛移位机械力的来源、甲状腺激素调控眼睛移位的信号通路、比目鱼类外形左右不对称与内脏左右不对称两者调控机制之间的关系以及比目鱼类眼睛左右不对称的进化起源等5个方面,系统地介绍了比目鱼类变态发育过程中眼睛移位的研究历史。重点介绍了本实验室提出的关于眼睛移位的组织学模型,以及眼睛移位信号调控途径的最新研究进展。发现并证明眶下皮肤组织细胞分裂导致眼睛移动,而眼睛移动进一步导致额骨变形,纠正了以往假说的谬误。最后,对比目鱼类眼睛移位和不对称进化起源进行了探讨,提出了解释比目鱼类不对称进化起源的新假说。     

光照强度对樱桃谷肉鸭c-fos、生物钟基因表达及褪黑激素的影响

【目的】研究持续黑暗下给予樱桃谷肉鸭不同强度的瞬时光照,对下丘脑、间脑、垂体和中脑中c-fos基因及相关生物钟基因的表达及血浆和肝脏中褪黑激素含量的影响。【方法】选用144只健康且体重接近的1日龄樱桃谷肉鸭饲养至21日龄,22日龄时随机分为2组,每组6个重复,持续黑暗7 d,期间自由采食和饮水,分别采用10 Lx和80 Lx的LED白光刺激1.5 h,暗适应1.5 h后立即从每个重复选取1只接近平均体重的肉鸭,检测下丘脑、间脑、垂体和中脑c-fos和生物钟基因的表达量,检测血浆和肝脏褪黑激素含量。【结果】10 Lx组的下丘脑和中脑c-fos表达量显著高于80 Lx光照组(P<0.05),间脑中c-fos的表达量显著低于80 Lx光照组(P<0.05),两组垂体组织中c-fos表达无显著影响(P>0.05)。与80 Lx组相比,10 Lx组下丘脑生物钟基因Bmal1、Bmal2、Clock和Per2表达量均显著提高(P<0.05),Cry1表达量也有提高的趋势。10 Lx组间脑Bmal1的表达量显著提高(P<0.05),Bmal2、Clock、Per2和Cr...     

温度和光照对骆驼蓬种子萌发特性的影响

本文研究了不同温度和光照对骆驼蓬6个不同居群种子萌发特性的影响,结果表明：在15℃-30℃范围内,骆驼蓬6个居群种子萌发率和萌发指数都表现出随着温度的升高而升高的趋7势,种子萌发的适宜温度范围为20℃-30℃,但不同居群种子最适萌发温度不同。在10℃／30℃（黑暗／光照）周期性变温条件下,种子的萌发率较高。光照不是骆驼蓬种子萌发的必要条件,但对种子萌发有重要的影响,持续光照和周期性光照条件下的种子萌发率明显高于全黑暗条件下的种子萌发率。     

光暗处理对水稻叶片光合关键酶的效应

稻苗置暗中24h后,Rubisco含量及Rubisco与可溶性蛋白的比值随光强的增加而提高;经2h光照后再置黑暗中,Rubisco含量在最初20min下降迅速,说明苗期Rubisco蛋白在光暗交替下周转较快.Rubisco的初始活力在光照下迅速增加,其上升倍数大大高于量的增加,光强越大达到最大活力所需的时间越短.照光后把稻苗置暗中,Rubisco初始羧化活力很快下降,说明Rubisco的光下活化及暗中失活迅速.Rubisco活化酶的含量随光照增加而逐渐上升,光照处理后再置暗中Rubisco活化酶含量不断下降,但速率不如Rubisco.Rubisco活化酶的活化只依赖低光强,光照处理后再置黑暗中,Rubisco活化酶活力迅速下降.     

短期黑暗对矮牵牛幼苗叶片光合结构及功能的影响

以矮牵牛（Petunia hybrida）为试验材料,常温黑暗条件处理1、4d和15d,后两种处理在光照（PFD=150μmol&#183;m^2&#183;S^-1）下恢复4、8d和12d,对幼苗叶片显微结构、叶绿体超微结构及光合功能进行了研究。结果表明：（1）与0d相比,黑暗处理1、4d和15d叶片厚度分别下降9．9％、16．9％和36．2％;栅栏组织厚度黑暗处理1d有显著减小,海绵组织厚度黑暗处理4d后有显著下降。黑暗处理1d的幼苗叶片,叶绿体片层排列紧密但方向稍紊乱;黑暗处理4d,叶绿体片层排列扭曲变形,叶绿体内有空洞;黑暗处理15d,叶绿体内布满空洞,趋于解体。恢复光照,黑暗处理4d幼苗叶片显微结构及叶绿体超微结构完全恢复,15d幼苗基本恢复。（2）黑暗处理后叶绿素、Pn、Gs、Ci、Fv／Fm和F／Fo均显著下降,Fo显著上升。恢复光照,以上光合特性各值均基本恢复到正常水平。黑暗及恢复光照过程中叶绿素含量的变化主要取决于Chla,而Chlb保持相对稳定;黑暗处理4d幼苗光合作用的下降主要是由气孔限制所致,而15d幼苗光合作用的下降主要是非气孔因素造成。     

光照周期对尼罗罗非鱼幼鱼昼夜节律调节的作用

为了研究尼罗罗非鱼幼鱼游泳行为在不喂食时是否存在昼夜节律和光照周期的调节作用,设计了光周期为光照(L)∶黑暗(D)=12 h∶12 h,持续的黑暗(DD),持续的光照(LL),光周期为L∶D=6 h∶6 h和光周期为L∶D=2 h∶2 h。结果表明:(1)光周期为L∶D=12 h∶12 h时,尼罗罗非鱼具有明显的昼夜节律,昼夜节律周期为(24. 3±0. 2) h;(2)尼罗罗非鱼的昼夜节律在持续的黑暗和光照下仍然存在,分别为(25. 1±1. 1) h和(25. 6±1. 0) h;(3)光周期为L∶D=6 h∶6 h时,尼罗罗非鱼仍具有明显的昼夜节律(12. 6±0. 5) h;(4)在光周期为L∶D=2 h∶2 h时,尼罗罗非鱼的昼夜游泳行为仍具有明显的昼夜节律,节律周期为(4. 0±2. 0) h。这些结果表明,尼罗罗非鱼具有以24 h为周期的内源性生物钟,但相比与外源性光照调控,内源性的生物钟对罗非鱼的调控较弱,外源性的光照周期才是调节尼罗罗非鱼幼鱼昼夜行为节律的主要因素。     

Photoelectric technique for measuring eye movements

By the system described, the movement of a stimulus and the correlated tracking movements of the eye are recorded simultaneously. The technique for measuring the eye movements consists of detecting and amplifying by photomultiplication the total amount of light passing through a small slit upon which is imaged a small portion of the light-dark field represented by the iris and sclera of the eye. This total amount of light varies directly with the angular position of the eye.     

高寒地区燕麦根际高效PGPR菌培养条件研究

用乙炔还原法及比色法对高寒草地燕麦根际分离的5个PGPR菌株(O3、O5、O6、O7、O8)在不同光照、pH值、盐分浓度和温度梯度下的生长能力进行了研究。结果表明:5株PGPR菌在较低的光照强度下生长受阻,高强度的光照有利于细菌的生长繁殖,其最适生长范围为2 000～3 000 Lx;固氮酶活性在pH 7.0～7.2范围之间表现最高;盐分(NaCl)浓度高于1 % 时PGPR菌生长受阻;PGPR菌最适宜的生长温度范围为25～30 ℃。     

Externalization of beta-adrenergic receptors promoted by myocardial ischemia

beta-Adrenergic receptors were identified in two fractions of guinea pig myocardium: a purified sarcolemmal fraction and a light vesicle (presumably intracellular) fraction. In the light vesicle fraction, which contained approximately 25 percent of the myocardial receptors under control conditions, the receptors appeared to be segregated from the stimulatory guanine nucleotide binding and catalytic components of adenylate cyclase. During myocardial ischemia, beta-adrenergic receptors were redistributed from the intracellular vesicles to the sarcolemmal fraction, where isoproterenol-stimulated adenylate cyclase activity was increased. These findings should facilitate further studies on cellular and molecular mechanisms that regulate adrenergic receptor traffic in the myocardium and may explain the rapid enhancement in adrenergic receptor expression that occurs with myocardial ischemia.     

厚荚相思光自养微繁殖技术研究

以厚荚相思组培苗为材料进行光自养微繁殖的生根培养研究。结果表明：不同培养基质对厚荚相思的生根有显著影响,以河沙为最优;不同营养液对厚荚相思的生根也有显著影响,以不合营养成分的水分为最优;不同光强模式在透气性好的河沙和透气性差的琼脂培养基上,对厚荚相思的生根、地上生物量和地下生物量有显著影响,光强模式2（0—7d低光强,光强为2500～3000lx,光照时间12h／d;8～10d光强达到4000～5000lx,光照时间14h／d;10d以后光强要达6000～8000lx,光照时间14h／d）为最优。     

Electroretinogram of the visually deprived cat

Cats kept in darkness from birth show a subnormal b-wave in the electroretinogram to 4 weeks of age but quickly develop the full response upon stimulation. When the cats are kept without light for 1 year, the response recovers slowly after intense stimulation. A 2-day exposure to light is sufficient to reverse this diminution in response.