Formation of cyclodextrins with cyclodextrin glucosyltransferase stimulated with polarized light

After illumination with white, linearly polarized light (WLPL), cyclodextrin glycosyltransferase produced mixture of α‐, β‐, and γ‐cyclodextrins (CD) with higher overall yield than did that enzyme when nonilluminated. The illumination also influenced the ratio of those CD and that effect depended on concentration of enzyme and illumination time. At a high enzyme concentration (0.64 U/cm³), regardless the illumination time, formation of β‐CD predominated. The highest yield of β‐CD was afforded after 1 h illumination and 2 h illumination led to a significant increase in the yield of γ‐CD. Three‐month storage of enzyme illuminated with WLPL did not reduce its enhanced activity. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

光照、湿度和培养基对苎麻疫霉卵孢子产生量的影响

采用3因素随机区组设计研究了光照、湿度和培养基对苎麻疫霉(hytophthoraboehmeriae)卵孢子产生量的影响。结果表明,各因子对卵孢子产生量的影响效应大小次序为培养基>光照>湿度,其中培养基和光照两因子影响均在0.01水平上显着。在供试的4种常用培养基上,卵孢子产生量的大小次序为：SLA培养基(SLA)>利马豆培养基(LBA)>V₆汁培养基(V₆A)>澄清的V₆汁培养基(V₆B).在设置的3种光照条件中,卵孢子产生量以连续黑暗处理最高,连续光照最低,光照与黑暗交替处理居中。3个试验因子间的所有互作对卵孢子产生量均有极显着的影响。在不同光照、湿度、培养基组合中,卵孢子产生量以低湿+连续黑暗+SLA组合最高,低湿+连续光照+V₆B组合最低。     

Developing portable widefield fundus camera for teleophthalmology: Technical challenges and potential solutions

A portable, low cost, widefield fundus camera is essential for developing affordable teleophthalmology. However, conventional trans-pupillary illumination used in traditional fundus cameras limits the field of view (FOV) in a snapshot image, and frequently requires pharmacologically pupillary dilation for reliable examination of eye conditions. This minireview summarizes recent developments in alternative illumination approaches for widefield fundus photography. Miniaturized indirect illumination has been used to enable compact design for developing low cost, portable, widefield fundus camera. Contact mode trans-pars-planar illumination has been validated for ultra-widefield fundus imaging of infant eyes. Contact-free trans-pars-planar illumination has been explored for widefield imaging of adult eyes. Trans-palpebral illumination has been also demonstrated in a smartphone-based widefield fundus imager to foster affordable teleophthalmology.     

湘黄种鸡露天散养时光照程序制定办法研究

湘黄种鸡露天散养时,合理的光照以提高产合格种蛋率是露天散养的重要技术之一。本研究采用人工光照与自然光照结合办法,对4个批次7 400套种鸡进行了研究观察,并与对应的同日龄全自然光照专业户鸡群比较,得出散养种鸡制定出合理的光照程序可使产合格蛋率提高21.93%。     

The importance of illumination level in the daily onset of flight activity in nocturnal moths

ABSTRACT. The daily onset of flight activity in nocturnal moths from Denmark and Florida was investigated in natural and experimental reductions of illumination. The daily cycle of illumination is described, especially the variation of the rate of change during the evening. Different species commence activity ('onset') at different mean light intensities. These means occur around the termination of twilight, at between 0 and –2.50 log lux. In a given species the illumination at mean onset is constant, and the dispersion of onsets in the population is constant with respect to the illumination. As a consequence, the dispersion with respect to time increases, the longer the duration of twilight. The temporal dispersion, therefore, depends upon season and latitude. A model describing the number of onsets in relation to the decrease of illumination is presented. At the physiological level it is proposed that a preparatory process precedes the actual onset of activity. This is observed as a latency between the light change and the activity onset. It is presumed to represent a change, from an inhibiting to a disinhibiting output from a controlling CNS centre, brought about by the reduction in illumination increasing the sensitivity of the centre to a 'sensitizer'. This might represent the Zeitgeber effect of illumination reduction. The results indicate that during a gradual decrease of illumination, the latency process is initiated by a certain low illumination and that it proceeds further, the lower the illumination. The faster the rate of decrease, the faster is the rate of the process, so that it is completed at about the same time as a threshold illumination for overt activity is reached, irrespective of the rate of decrease. However, at very fast reductions of illumination, the physiological process cannot keep pace with the reduction, and activity onset occurs at a lower illumination than normal.     

光照,湿度和培养基对苎麻疫霉卵孢子产生量的影响

采用３因素随机区组设计研究了光照、湿度和培养基对苎麻疫霉（Ｐｈｙｔｏｐｈｔｈｏｒａｂｏｅｈｍｅｒｉａｅ）卵孢子产生量的影响．结果表明,各因子对卵孢子产生量的影响效应大小次序为培养基＞光照＞湿度,其中培养基和光照两因子影响均在０．０１水平上显著．在供试的４种常用培养基上,卵孢子产生量的大小次序为：ＳＬＡ培养基（ＳＬＡ）＞利马豆培养基（ＬＢＡ）＞Ｖ６汁培养基（Ｖ６Ａ）＞澄清的Ｖ６汁培养基（Ｖ６Ｂ）．在设置的３种光照条件中,卵孢子产生量以连续黑暗处理最高,连续光照最低,光照与黑暗交替处理居中．３个试验因子间的所有互作对卵孢子产生量均有极显著的影响．在不同光照、湿度、培养基组合中,卵孢子产生量以低湿＋连续黑暗＋ＳＬＡ组合最高,低湿＋连续光照＋Ｖ６Ｂ组合最低．     

光照、碳源和还原力对大豆玉米苗期氧化亚氮释放量的影响

使用封闭式箱法,对大豆和玉米两种植物在苗期的N2O释放速率日变化及其同光强、气温的相关性进行了研究,同时对遮光、外加碳源和还原力对N2O释放速率的影响进行了分析．结果表明,两种植物苗期N2O释放速率在日间有两个释放高峰,分别出现在10：30和14：30．遮光处理实验结果证明,遮光后植物的N2O释放速率明显增加;相关性分析表明,苗期大豆在光强低于11345Lx时,N2O释放速率与光强呈正相关关系(R^2=0．7332),光强高于11345Lx时,呈负相关关系(R^2=0．7755),而苗期玉米在光强低于20000Lx时,N2O释放速率与光强呈正相关关系(R^2=0．8711),光强高于11345Lx时,呈负相关关系(R^2=0．8972)．加入一定量的碳源(葡萄糖),可使遮光植物N2O的释放速率明显下降,由于同化力(NADH)的介入,在一定程度上影响了N2O的排放通量,同样使得N2O的释放量下降．     

The biphasic fluence response of carotenogenesis in Neurospora crassa: Temporary insensitivity of the photoreceptor system

Whether or not illumination is continuous or interrupted during the span in which increasing illumination time periods (i.e., increasing fluences) have no different effect on carotenogenesis is optional, in regard to the amount of carotenoids produced (revealing the plateau of the biphasic fluence response curve). This indicates temporary insensitivity. When the time delay between the onsets of the initial and second illumination is extended beyond the expanse of the plateau, the amount of carotenoids induced by the second illumination depends on the time elapsed following the first exposure; after ca. 2 h, maximum competence for a second induction is completely restored. On the other hand, the amount of carotenoids induced by a second illumination also depends on the duration of this second illumination, but, unlike the dependence in a single illumination, results in a different fluence response curve for the second exposure. When UV-A is used for induction, the refractory period which follows the first exposure seems to be the same as for blue light, suggesting vision of UV-A and blue light by the same photoreceptor system.     

Mono‐ and dichromatic LED illumination leads to enhanced growth and energy conversion for high‐efficiency cultivation of microalgae for application in space

Illumination with red and blue photons is known to be efficient for cultivation of higher plants. For microalgae cultivation, illumination with specific wavelengths rather than full spectrum illumination can be an alternative where there is a lack of knowledge about achievable biomass yields. This study deals with the usage of color LED illumination to cultivate microalgae integrated into closed life support systems for outer space. The goal is to quantify biomass yields using color illumination (red, blue, green and mixtures) compared to white light. Chlamydomonas reinhardtii was cultivated in plate reactors with color compared to white illumination regarding PCE, specific pigment concentration and cell size. Highest PCE values were achieved under low PFDs with a red/blue illumination (680 nm/447 nm) at a 90 to 10% molar ratio. At higher PFDs saturation effects can be observed resulting from light absorption characteristics and the linear part of PI curve. Cell size and aggregation are also influenced by the applied light color. Red/blue color illumination is a promising option applicable for microalgae‐based modules of life support systems under low to saturating light intensities and double‐sided illumination. Results of higher PCE with addition of blue photons to red light indicate an influence of sensory pigments.     

Photopreferendum of migratory and nonmigratory larvae of European river lamprey <Emphasis Type="Italic">Lampetra fluviatilis</Emphasis>

In the light gradient installation, the larvae of European river lamprey Lampetra fluviatilis of 0+ age, migrating downstream (downstream migrants), are distributed predominantly over the zone of dusk illumination (150–1 lx) and less so over the daylight zone (2500–150 lx) and night illumination zone (<1 lx). In 0+ larvae that passed over to the sedentary lifestyle, the photopreferendum changes: they avoid the dusk and daytime illumination and prefer nighttime illumination. Such photopreferendum is retained in later larvae of lamprey (1+ and older).     

Light modes and ovulation function in rats in ontogenesis

Enhancement of illumination was shown to lead to occurrence of early and more obvious age-dependent changes of ovulation cycle in rats as compared with the same changes in animals staying in conditions of light deprivation or standard illumination. The effect of 24-hour illumination during a year induced more obvious and still earlier changes of the estrus cycle that the effect of natural illumination in the North-West of Russia with its peculiar yearly photo-periodicity (short light day in the autumn-winter period and "white nights" in the spring-summer period).     

Influence of age and illumination on distribution of several calvin cycle enzymes in greening barley leaves

Activities of phosphoriboisomerase, phosphoribulokinase, and ribulose 1,5-diphosphate carboxylase, protein content, and chlorophyll accumulation in dark-grown barley seedlings were measured before and after illumination. Enzymatic activities, levels of soluble protein, and accumulation (upon illumination) of chlorophyll in leaves declined from tips toward the base. In response to increasing time of illumination, chlorophyll accumulation and activities of phosphoribulokinase and ribulose 1,5-diphosphate carboxylase (enzymes located in chloroplasts) increased most in tip portions whereas activity of phosphoriboisomerase and levels of soluble protein (constituents not confined to chloroplasts) increased similarly in all sections of the leaf. Maximum activity of phosphoribulokinase and maximum accumulation of chlorophyll shifted toward median portions of the leaf blade with increased age of seedling before illumination. Maximum activity of ribulose 1,5-diphosphate carboxylase and maximum level of soluble protein occurred in all leaf sections when the seedlings were 7 days of age before illumination.     

Post-illumination kinetics of cytochrome f reduction in chloroplast thylakoid in the presence of dibromothymoquinone

Addition of dibromothymoquinone (DBMIB) to isolated chloroplast thylakoids reduces cytochrome f in the dark. Reduced cytochrome f is oxidised when the thylakoids are illuminated, and is re-reduced in the subsequent darkness. The rate of re-reduction in the dark is faster after red (650 nm) illumination than after far red (713 nm) illumination. In the presence of DCMU or upon heat treatment or at high (greater than 10 microM) concentration of DBMIB the rate of dark reduction after red illumination becomes slower and equal to that after far red illumination, suggesting that photosystem II electron transfer at least upto plastoquinone facilitates DBMIB-mediated reduction of cytochrome f in the thylakoids.     

Beneficial interaction between photosynthesis and respiration in mesophyll protoplasts of pea during short light-dark cycles

The respiratory uptake or photosynthetic evolution of oxygen by mesophyll protoplasts of pea ( Pisum sativum L. cv. Arkel) were monitored during successive short. (3–5 min) cycles of darkness and illumination. The rate of respiration was nearly doubled after 3–4 short periods of illumination while there was a 15–20% enhancement in photosynthesis with cycles of illumination and darkness preceding illumination. Such interaction between photosynthesis and respiration was statistically significant when bicarbonate was present in the reaction medium. The inhibitors of photosynthesis [3(3,4–dichlorophenyl)-l,l-dimethylurea (DCMU), glyceraldehyde] decreased respiration after periods of illumination, whereas inhibitors of respiratory electron transport (Rotenone, antimycin A, NaN₃) suppressed photosynthesis, as well. We suggest that a rapid beneficial interaction exists between photosynthesis and respiration in protoplasts, even during short cycles of light and darkness.     

Flat-top illumination profile in an epifluorescence microscope by dual microlens arrays

Low uniformity in illumination across the image plane impairs the ability of a traditional epifluorescence microscope to quantify fluorescence intensities. Two microlens arrays (MLAs) were introduced into the illumination path of two different epifluorescence microscope systems to improve the uniformity of the illumination. Measurements of the uniformity of illumination were performed with a CCD camera in the focal plane and with fluorescent beads in the image plane. In semi critical alignment, a uniformity of illumination of 15-23% was found compared with 1-2% in the modified system. Coefficient of variation (CV) of fluorescent beads measured on the unmodified system was 20.4% ± 5.3% in semi critical alignment and 10.8% ± 1.3% in Koehler alignment. On the MLA systems, CV was 7.9% ± 2.0% and on a flow cytometer, the CV was 6.7% ± 0.7%. Implementation of MLAs in an epifluorescence microscope improves the uniformity of illumination, thereby reducing the variation in detection of fluorescent signals of the measured objects and becomes equivalent to that of flow cytometry.     

Increase in protoporphyrin IX after 5-aminolevulinic acid based photodynamic therapy is due to local re-synthesis.

Protoporphyrin IX (PpIX) fluorescence that is bleached during aminolevulinic acid (ALA) mediated photodynamic therapy (PDT) increases again in time after treatment. In the present study we investigated if this increase in PpIX fluorescence after illumination is the result of local re-synthesis or of systemic redistribution of PpIX. We studied the spatial distribution of PpIX after PDT with and without cooling using the skin-fold observation chamber model. We were unable to show a correlation between the local PpIX fluorescence increase and the distance from a blood vessel. The spatial distribution of PpIX fluorescence within normal tissue or tumour is not changed in response to the illumination. These observations suggest that there is no diffusion of PpIX into the treated tissue. Cooling the tissue to 12 degrees C, a temperature at which PpIX synthesis is inhibited, inhibited the PpIX fluorescence increase normally observed after illumination. We also found a strong correlation between local PpIX photobleaching during illumination and the fluorescence intensity 1 h after illumination similar to what we have observed in patients treated with ALA-PDT. Therefore we conclude that the increase in PpIX fluorescence after illumination is due to local cellular re-synthesis.     

Light-dependent degradation of the D1 protein in photosystem II is accelerated after inhibition of the water splitting reaction

Strong illumination of oxygen-evolving organisms inhibits the electron transport through photosystem II (photoinhibition). In addition the illumination leads to a rapid turnover of the D1 protein in the reaction center of photosystem II. In this study the light-dependent degradation of the D1 reaction center protein and the light-dependent inhibition of electron-transport reactions have been studied in thylakoid membranes in which the oxygen evolution has been reversibly inhibited by Cl- depletion. The results show that Cl(-)-depleted thylakoid membranes are very vulnerable to damage induced by illumination. Both the D1 protein and the inhibition of the oxygen evolution are 15-20 times more sensitive to illumination than in control thylakoid membranes. The presence, during the illumination, of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) prevented both the light-dependent degradation of the D1 protein and the inhibition of the electron transport. The protection exerted by DCMU is seen only in Cl(-)-depleted thylakoid membranes. These observations lead to the proposal that continuous illumination of Cl(-)-depleted thylakoid membranes generates anomalously long-lived, highly oxidizing radicals on the oxidizing side of photosystem II, which are responsible for the light-induced protein damage and inhibition. The presence of DCMU during the illumination prevents the formation of these radicals, which explains the protective effects of the herbicide. It is also observed that in Cl(-)-depleted thylakoid membranes, oxygen evolution (measured after the readdition of Cl-) is inhibited before electron transfer from diphenylcarbazide to dichlorophenolindophenol.(ABSTRACT TRUNCATED AT 250 WORDS)     

The combined effects of noise and illumination on the performance efficiency of visual search and neuromotor task components

A battery of performance tests consisting of 'letter cancellation,' 'hand 'precision,' 'two-hand coordination,' and 'tweezer dexterity' were administered on 12 desk workers in an illumination chamber under six different combinations of noise and illumination made out of two levels of white noise (70 and 100 dB) and three levels of illuminations (50, 150, and 300 lx). The objective was to find out the combined effects of noise and illumination on the performance efficiency of the above tests. A 6 x 6 latin square design was followed. A three-way analysis of variance reflected significant combined effects of noise and illumination on the accuracy scores of the letter cancellation test and hand precision test and the efficiency score of the latter test. Significant separate effects of noise were, however, observable on the speed scores and efficiency scores of the letter cancellation test and that of illumination on the speed scores of this test as also the accuracy scores of the tweezer dexterity test. Studies ascertaining the effects of heat stress in combination with noise and illumination on human performance efficiency have been suggested.     

Depth Structure from Asymmetric Shading Supports Face Discrimination

To examine the effect of illumination direction on the ability of observers to discriminate between faces, we manipulated the direction of illumination on scanned 3D face models. In order to dissociate the surface reflectance and illumination components of front-view face images, we introduce a symmetry algorithm that can separate the symmetric and asymmetric components of the face in both low and high spatial frequency bands. Based on this approach, hybrid faces stimuli were constructed with different combinations of symmetric and asymmetric spatial content. Discrimination results with these images showed that asymmetric illumination information biased face perception toward the structure of the shading component, while the symmetric illumination information had little, if any, effect. Measures of perceived depth showed that this property increased systematically with the asymmetric but not the symmetric low spatial frequency component. Together, these results suggest that (1) the asymmetric 3D shading information dramatically affects both the perceived facial information and the perceived depth of the facial structure; and (2) these effects both increase as the illumination direction is shifted to the side. Thus, our results support the hypothesis that face processing has a strong 3D component.     

光照时间对果蝇发生量的影响

设置6个光照时间梯度和两个光照强度梯度,分别对3种（基因型）果蝇进行光照处理,结果显示：在5001ux光照强度下,光照处理3h／d的果蝇发生量最少,其他各光照时间果蝇发生量无显著差异;1000lux光照强度下,不同光照时间果蝇发生量差异不显著,而不同基因型果蝇间表现出显著差异;连续光照处理使黑檀体果蝇后代数明显减少。