Time course of color induction in the honeybee

Color induction in the honeybee is investigated in color discrimination experiments. An individual bee walks in a dark arena and is trained to a self-luminant stimulus presented from below. In the dual-choice tests the dark background is replaced by a colored induction stimulus. Choice behavior is recorded by TV camera and analyzed by computer. Successive color induction is separated from simultaneous induction by analysis of the walking paths. Only successive color induction occurs. Simultaneous effects are not observed. That is a stimulus acts as a color inducing stimulus only when the bee crosses this stimulus. Thus, the color perceived by a given eye region is found to be dependent on the viewing history, but not on the stimuli presented simultaneously on neighboring parts of the retina. Color induction in the honeybee described in terms of selective sensitivity decrease (adaptation) does not explain all behavioral effects induced by the stimulus. The time course of successive color induction is calculated from the exposure times to the induction stimulus and from the choice behavior. The data suggest that color induction is complete after a few seconds. Photoreceptor adaptation is sufficient to explain the observed time course.     

An automated differential thermal and potentiometric titration apparatus for binding studies

A differential pH-termal titration apparatus is described which can detect pH differences with a sensitivity of ±0.0001 pH units and a thermal sensitivity of ±0.00002°C at a time constant of 0.1 s. With a reaction which yields 1 kcal mol⁻¹, the current system can detect concentrations as low as 4×10⁻⁶ M or, in a 2 ml volume, a total amount of 40 nmol. With a time constant of 0.1 s, the sensitivity is 20±4 μ°C. The experimental protocol is specified by a microprocessor and three modes of operation are possible: titration at constant rate of reagent addition, titration at variable rates of addition so that the contents of both cells are at either constant pH or at a constant temperature and variable rate when a rate of change is specified. Experimental data are collected in files, corrected for heat loss, initial baseline drift, and changes in volume. The final corrected from the standardized run of 0.01338 M HCl in 0.2 M KCl at 25°C calibrate the pH scale yielded the calorimetric conversion constants and pK_w which are calculated and stored for subsequent corrections for the titration of an unknown acid or the measurement of bindin constants and heats.     

DNA reassociation kinetics and hybridization in different angiosperms

Reassociation kinetics ofDaucus carota andPetroselinum crispum (Apiaceae), andDatura innoxia (Solanaceae) are presented. Hybridization of³H-labelled DNA of two carrot cultivars indicate strong qualitative homologies of DNA sequences; nevertheless, certain quantitative differences in some Cotregions seem to exist. However, homologous sequences ofDaucus DNA with DNA ofDatura, and, suprisingly, even with DNA ofPetroselinum are very restricted: between 8% in the repeated regions and ca. 7–9% in the unique regions.     

不同灌溉量夏玉米叶绿素含量的高光谱特征及其反演

植物叶绿素含量直接影响其光合作用，并与植物的光谱特征密切相关。以夏玉米为研究对象，采用人工控水方法研究了夏玉米七叶期不同灌溉量下冠层叶绿素含量特征及其与光谱特征之间的关系。结果表明：灌溉量越少，夏玉米叶片叶绿素含量越低，冠层光谱反射率越高，绿峰位置"红移"，而红边位置"蓝移"。叶绿素含量与光谱特征参数、植被光谱指数之间存在极显著相关关系，据此建立了冠层叶绿素含量高光谱估算模型，且基于植被指数模型较基于单一光谱特征参数模型模拟效果更好。研究结果可为夏玉米叶绿素含量的快速无损测定以及夏玉米干旱监测提供依据。     

Preparation and Evaluation of Differently Sulfonated Styrene–Divinylbenzene Cross-linked Copolymer Cationic Exchange Resins as Novel Carriers for Drug Delivery

The differently sulfonated styrene–divinylbenzene cross-linked copolymer cationic exchange resins were prepared by oil-in-water polymerization and varied degrees of sulfonation. Several characteristics of the obtained resins were evaluated, i.e., Fourier transform infrared spectra, the ion-exchange capacity, microscopic morphology, size, and swelling. The resin characteristics were altered in relation to the degree of sulfonation, proving that differently sulfonated resins could be prepared. The behavior of chlorpheniramine (CPM) loading and in vitro release in the USP simulated gastric (SGF) and intestinal fluids (SIF) of the obtained resins were also evaluated. The CPM loaded in the resinates (drug-loaded resins) increased with the increasing degree of sulfonic group and hence the drug binding site in the employed resins. The CPM release was lower from the resins with the higher degree of sulfonic group due to the increase in the diffusive path depth. The CPM release was obviously lower in SGF than SIF because CPM, a weak base drug, ionized to a greater extent in SGF and then preferred binding with rather than releasing from the resins. In conclusion, the differently sulfonated resins could be utilized as novel carriers for drug delivery.     

彩色多普勒超声对原位肝移植术后血流动力学研究

目的:探讨彩色多普勒超声(CDI)在原位肝移植术后对移植肝血流动力学变化的诊断价值。方法:应用CDI连续观察6例原位肝移植患者移植肝脏形态学变化,肝动脉峰值流速(HAmax)、门静脉及肝静脉平均流速(PVmean,HVmean)等指标,并以30例健康成人男性肝脏的血流动力学参数作为正常对照组。结果:在术后2周内肝脏移植组的HAmax低于正常对照组,1周内表现更为明显;术后1周内移植肝脏组的PVmean高于正常对照组,1周后表现不明显;移植肝脏组的Hvmean与正常对照组相比无明显差异。2周后,HA、PV和HV的血流速度基本上趋于正常。结论:CDI技术对了解肝移植术后移植肝的灌注情况,及早发现肝移植术后早期的并发症有重要意义。     

日本血吸虫虫卵、童虫和雌雄成虫膜蛋白的双向电泳

血吸虫寄生生活复杂,中间宿主和终末宿主转换,有性繁殖和无性繁殖交替,由其感染引起的血吸虫病仍严重危害人畜健康(陈贤义等,2002).研究表明,血吸虫不仅能利用宿主的免疫信号分子伪装自己获得宿主的免疫兼容(Salzet et al.,2000),而且还在血吸虫中克隆到宿主信号分子的受体(Ahmed et al.,2001).     

Patterns of morphological and genetic diversity of Valeriana jatamansi Jones in different habitats and altitudinal range of West Himalaya,India

Importance to know and understand diversity of Himalayan plants is increasingly recognized considering the fact that various natural and anthropogenic pressures might bring about serious influences to morphological and genetic diversity of the vegetation in the region. In this context, Valeriana jatamansi was investigated in detail, taking into account its importance in various Ayurvedic and modern medicines. Randomly selected mature plants from twenty five different populations (located between 1215 m to 2775 m asl) of V. jatamansi were analysed for their morphological attributes. Further, ISSR markers were used to detect genetic variation among 151 plants of selected 25 populations. Use of 20 primers yielded 125 reproducible polymorphic loci which were used to estimate different parameters of genetic diversity. These parameters were in turn applied to develop relationships with habitat types and altitude range. Significant variation (p < 0.05) in above ground dry weight (AGDW) and below ground dry weight (BGDW) across the populations was observed. Nei's genetic diversity index (He) ranged from 0.25 to 0.37 across the populations, with a mean of 0.31. Genetic diversity exhibited a decreasing trend with increasing altitude, and maximum diversity (He = 0.325) was observed in the range of 1201–1500 m asl. Among the different habitat conditions, highest genetic diversity (He = 0.334; Pp = 84.38) was observed in grassland habitats while minimum in mixed forest habitats (He = 0.285; Pp = 72.433). The genetic diversity (He) had significant negative relationships with AGDW, BGDW and rhizome diameter (Pearson r = −0.359, −0.424 and −0.317, respectively; p < 0.05). The genetic characterization of V. jatamansi from the western Himalaya by this study suggests influences of habitat types and the altitudinal range upon genetic diversity, and based on these proposals for conservation strategies in favour of the species are made.     

不同生境与花部特征对巫山淫羊藿结实特性的影响

对不同生境中巫山淫羊藿结实特性进行比较研究。结果表明:(1)三个种群在繁殖时期中不同花部特征的植株繁殖投资差异不大,如每株分枝数、每株花序数和每株开花数差异均不显著;(2)三个种群中每株结实数、每株结实率、每花序结实数在不同花部特征中差异显著,PLS和SAA要显著大于PESS;(3)三种花部特征在不同生境中单株分枝数和单株花序数均无显著差异。在不同花部特征中种群1开花数量相较少,因而在结实方面均值均要小于种群2和种群3;(4)不同花部特征的果实饱满种子数、败育数和败育率均具有显著差异,而种子数差异不大,但在种群间均无显著的差异。说明种子的多少更多地受到花部特征的影响。总之,巫山淫羊藿的结实特性受到生境和花部特征的双重影响,其中花型比生境对巫山淫羊藿结实特性的影响更为明显。     

Reactive black-5 azo dye treatment in suspended and attach growth sequencing batch bioreactor using different co-substrates

Treatment of textile wastewater is a big challenge because of diverse chemical composition, high chemical strength and color of the wastewater. In the present study, treatment of wastewater containing reactive black-5 azo dye was studied in anaerobic sequencing batch bioreactor (SBBR) using mixed liquor suspended solids (MLSS) from suspended and attach growth bioreactors. MLSS at concentration of 1000 mg/L and reactive black-5 azo dye at 100 mg/L were used. A culture (10⁸–10⁹ CFU/ml) of pre-isolated bacterial strains (Psychrobacter alimentarius KS23 and Staphylococcus equorum KS26)) capable of degrading azo dyes in mineral salt medium was used to accelerate the treatment process in bioreactor. Different combinations of sludge, culture and dye were used for treatment using different co-substrates. About 85% COD removal was achieved by consortium (MLSS + KS23 + KS26) after 24 h in attach growth bioreactor. Similarly, 92% color removal was observed with consortium in attach growth bioreactor compared to 85% color removal in suspended bioreactor. Addition of bacterial culture (20%, v/v) to the bioreactor could enhance the rate of color removal. This study suggests that biotreatment of wastewater containing textile dyes can be achieved more efficiently in the attach growth bioreactor using yeast extract as a co-substrate and MLSS augmented with dye-degrading bacterial strains.