The Influence of Genotype and Environment on the Physiological and Metabolic Diversity ofFusarium compactum

Talbot, N. J., Vincent, P., and Wildman, H. G. 1996. The influence of genotype and environment on the physiological and metabolic diversity ofFusarium compactum. Fungal Genetics and Biology20,254–267. Fungal species produce a large variety of secondary metabolites which are of considerable interest to the pharmaceutical industry. It is clear that the secondary metabolite production of a species varies significantly in strains from different geographic locations and from different habitats. The influence of genotype and environment on metabolite production is, however, poorly understood. In this study we examined the influence of genotypic variability, physiological variability, environmental location, and habitat on metabolite production byFusarium compactum.Isolates of the fungus from two geographic locations and two distinct habitat types were examined for growth on 95 different carbon sources, and genotypic variability was determined using RAPDs and rDNA–RFLP analysis. In a blind test secondary metabolite production was assessed using HPLC profiles of methanolic cell extracts. A number of correlations were observed between genotypic groupings, as determined using parsimony, and specific metabolite production. Similar correlations were also observed with physiological groups although genotypic analysis proved to be a more sensitive predictor of metabolite variability. The data suggest a complex relationship between environment, genotype, and metabolite production but highlight the use of genetic screening as a means of optimizing the chances of identifying a wide range of metabolites from a given species.     

Physiological Adaptations of Crayfish to the Hypoxic Environment

SYNOPSIS. Crayfish routinely encounter waters of reduced oxygentension, resulting in a broad array of behavioral and physiologicalresponses. Many animals when faced with this stress will simplyremove themselves from the irritating environment through voluntarymigration. When an animal, either by choice or through physicalconstraints remains in a hypoxic environment it must compensatefor the reduction in O₂ availability. Many crayfish have theability to maintain oxygen consumption independent of waterPo₂ down to some critical level; below this the animal can nolonger maintain normoxic levels of aerobic metabolism. Regulationof oxygen uptake is thought to be due to a hypoxia-induced hyperventilationalong with an increase in hemocyanin O₂ affinity and an improvementin the ability of the respiratory surfaces to transfer O₂. Crayfishexposed to a reduction in water oxygen also show a strong bradycardia,which is compensated for by an increase in stroke volume, resultingin a maintenance of cardiac output. The adaptive advantage ofthis response is uncertain. As water Po₂ drops crayfish havebeen shown to redistribute cardiac output, presumably throughthe action of the cardioarterial valves. Hemolymph is shuntedto the anterior end of the animal, resulting in a greater perfusionof nervous tissue. The animals' ability to detect changes inwater Po₂ appear to result from O₂ sensitive receptors locatedon the gills or in the branchiocardiac veins. The integratedphysiological response toward environmental hypoxia allows thecrayfish to not only deal with the stress but to maintain activity.     

大学生人际价值观现状调查

目的:调查大学生人际价值观的基本状况.方法:采用大学生人际价值观问卷对618名1-4年级大学生进行调查.结果:大学生在人际交往过程中首先看重的是心理因素,其次是生理因素,最后是社会因素;男生在生理因素(比如外表、健康等)分值高于女生(P＜0.01);文科生在能力、经历和帮助上分值高于理科生(P＜0.05);不同年级、不同家庭月收入的大学生在人际交往价值观上也存在差异显著性(P＜0.05).结论:大学生人际价值观受性别、学科、年级等因素的影响.     

Physiological Properties of Nitrogen-scavenging Bacteria from the Marine Environment

Nine selected strains of marine bacteria from the marine environment, although taxonomically heterogeneous in character, exhibited a capacity for prolonged growth on 'nitrogen-free' media; only one strain, a Klebsiella sp., fixed dinitrogen under any of a considerable range of test conditions. The non-nitrogen-fixing bacteria were able to scavenge low levels of nitrogenous materials, principally ammonia, from the atmosphere. Contrary to previous suggestions, this growth did not have an abnormally low cellular protein and nitrogen content. Some strains with apparently low intracellular protein contents, as determined on a cellular dry weight basis, showed accumulations of carbonaceous storage products which distorted the cytochemical analyses. Representative strains grown in chemostat culture showed a high affinity (i.e. low Ks values—0.35–0.52 μmol/1) for the NH₄+ ion, compared with Escherichia coli (1.75 μmol/1) and preliminary studies of their glutamine synthetases suggested that the affinities ( K_m values—0.25–0.29 μmol/1) of this enzyme for hydroxylamine were similar to the few values reported for other marine bacteria.     

生理性起搏的历史及研究现状

右心室心尖部起搏易引起非同步性的房室收缩与舒张,损害心脏功能,导致心力衰竭.而生理性起搏器与之相比,能够模拟生理传导,保持房室、双室同步起搏,满足患者不同情况下的生理性需要,成为近年来临床研究的重要成果之一,本文将就生理性起搏的历史和研究现状进行简要综述.     

腐植酸对植物生理活动的影响

本文介绍了腐植酸的形成、提取、分类以及活性基团等方面的特征。腐植酸能影响植物的多种生理活动,包括植物的生长、营养元素的吸收、蛋白质和核酸的合长、光合作用、呼吸作用以及有些酶的活性等。腐植酸对植物的这些作用受自身不同成分、浓度、植物种类、外界营养条件等多方面的影响。本文也从细胞或分子水平讨论了腐植酸促进植物生长、影响营养元素吸收促进呼吸作用的机理。     

利用PHI数据进行区域性植物生理信息探测与分析

本次试验研究选择两个实验区:沼泽地和植被茂盛区.利用2000年9月上旬在黑龙江省大兴安岭地区获取的推帚式超光谱成像,(PHI, pushbroom hyperspectral imager)数据进行区域性植物生理量(主要是叶绿素)的探测与生态分析.在叶绿素含量探测中,结合所获取的成像光谱PHI数据的特点,在比较不同技术方法的基础之上,选用了有效而简单可靠的RARS(Ratio analysis of reflectance spectra)指数.该色素指数与植物叶绿素a、b含量拟合的相关系数( R )达0.8以上.利用PHI数据和野外实测植物光谱分别建立沼泽地和植被茂盛区的RARS指数模式,分别得到具有指示两试验区的叶绿素a (Chl a)、叶绿素b (Chl b)以及类胡萝卜素(Cars)的参数图像.更进一步地利用Blackburn(1998)所建立的RARS指数与叶绿素浓度之间的强拟合方程,相对定量估算了叶绿素a、b浓度的区域性分布,清晰地反映出植被生态状况和差异.这与野外实地考察较为一致.     

利用叶绿素荧光监测微藻的生长及生理状态

衣藻与扁藻是生产生物柴油的优势藻种,监测其生长和生理状况是利用它们生产生物柴油的关键环节。本研究通过叶绿素荧光对这两种微藻的细胞密度进行监测并利用多激发波长调制叶绿素荧光仪(MultiColor-PAM)检测其在不同生长条件下的生理状况,获得本研究中两种藻的适宜的培养温度/光照强度:衣藻为28℃/80μmol/m~2·s~(-1),扁藻为28℃/100μmol/m2·s~(-1),利用叶绿素荧光可以便捷准确的监测微藻的生长及生理状态,为微藻培养及其代谢产物积累的研究提供切实可行的无损伤的检测方法。     

温度和湿度对蟾蜍生理功能的影响

蟾蜍随机分为室温干燥、室温保湿、低温保湿和低温冬眠组,观察禁食蟾蜍在不同温度和湿度条件下的生存时间、体重变化、心脏活动、腓肠肌收缩功能和坐骨神经干动作电位,探寻能够延长禁食蟾蜍生存时间和机体生理功能维持时间的途径。结果显示,室温干燥组蟾蜍体重自实验第1 d起显著性下降(P<0.01),其它组无显著性变化。室温干燥、室温保湿、低温保湿和低温冬眠组蟾蜍的累计死亡率分别为100%(第6 d)、45.83%(第26 d)、16.67%(第36 d)、0%。除室温保湿组蟾蜍的心脏舒缩幅度自实验第20 d起下降之外(P<0.05),其它组的心肌舒缩幅度和心率无显著性变化。室温干燥组蟾蜍的腓肠肌收缩幅度自实验第1 d开始下降,第4 d起有显著性差异(P<0.05),低温保湿组在第27 d也显著性下降(P<0.05),其他组未发生显著性变化。各组蟾蜍坐骨神经干动作电位未发生显著性改变。充足的湿度和适当降温,尤其保持冬眠,能够延长禁食蟾蜍的生存时间和机体生理功能维持时间。     

Influence of Caffeine on Physiological and Cognitive Functions of Humans

The review is devoted to the analysis of the effect of caffeine on physiological and cognitive functions of humans. The methodological aspects of experiments with the use of caffeine are discussed, in particular, the dosage, the frequency of use, and in combination with other products. The possibilities of the use of caffeine for studying physiological and mental phenomena, as well as age-related and individual psychological differences in reactions to caffeine, were shown.     

利用PHI数据进行区域性植物生理信息探测与分析

本次试验研究选择两个实验区 :沼泽地和植被茂盛区。利用 2 0 0 0年 9月上旬在黑龙江省大兴安岭地区获取的推帚式超光谱成像 ,(PHI,pushbroomhyperspectralimager)数据进行区域性植物生理量 (主要是叶绿素 )的探测与生态分析。在叶绿素含量探测中 ,结合所获取的成像光谱PHI数据的特点 ,在比较不同技术方法的基础之上 ,选用了有效而简单可靠的RARS(Ratioanalysisofreflectancespectra)指数。该色素指数与植物叶绿素a、b含量拟合的相关系数 (R)达 0 .8以上。利用PHI数据和野外实测植物光谱分别建立沼泽地和植被茂盛区的RARS指数模式 ,分别得到具有指示两试验区的叶绿素a (Chla)、叶绿素b (Chlb)以及类胡萝卜素 (Cars)的参数图像。更进一步地利用Blackburn(1998)所建立的RARS指数与叶绿素浓度之间的强拟合方程 ,相对定量估算了叶绿素a、b浓度的区域性分布 ,清晰地反映出植被生态状况和差异。这与野外实地考察较为一致。     

增加环境丰富化模具对实验豚鼠生长及行为的影响

目的在实验豚鼠饲养盒内增加梯形和管形两种不同的模具,进行环境丰富化模具对豚鼠生长及行为影响的研究。方法每组豚鼠饲养4周,每周称1次体重,记录体重变化趋势,并观察豚鼠行为变化。结果放入模具的豚鼠生长情况优越于对照组,管形模具优于其他实验组。结论增加环境丰富化模具有利于豚鼠生长,且管形模具更接近豚鼠自然洞穴状态,更加有利于豚鼠实现自然躲藏行为和良好的生长、生活。     

The Influence of Socioeconomic Status on Children's Brain Structure

Children's cognitive abilities and school achievements are deeply affected by parental socioeconomic status (SES). Numerous studies have reported lower cognitive performance in relation to unfavorable environments, but little is known about the effects of SES on the child's neural structures. Here, we systematically explore the association between SES and brain anatomy through MRI in a group of 23 healthy 10-year-old children with a wide range of parental SES. We confirm behaviorally that language is one of the cognitive domains most affected by SES. Furthermore, we observe widespread modifications in children's brain structure. A lower SES is associated with smaller volumes of gray matter in bilateral hippocampi, middle temporal gyri, left fusiform and right inferior occipito-temporal gyri, according to both volume- and surface-based morphometry. Moreover, we identify local gyrification effects in anterior frontal regions, supportive of a potential developmental lag in lower SES children. In contrast, we found no significant association between SES and white matter architecture. These findings point to the potential neural mediators of the link between unfavourable environmental conditions and cognitive skills.     

Impact of Temperature on the Physiological Status of a Potential Bioremediation Inoculant, Arthrobacter chlorophenolicus A6

Arthrobacter chlorophenolicus A6 (A6) can degrade large amounts of 4-chlorophenol in soil at 5 and 28°C. In this study, we investigated the effects of temperature on the physiological status of this bacterium in pure culture and in soil. A derivative of A6 tagged with the gfp gene (encoding green fluorescent protein [GFP]) was used to specifically quantify A6 cells in soil. In addition, cyano-ditolyl-tetrazoliumchloride was used to stain GFP-fluorescent cells with an active electron transfer system (“viable cells”) whereas propidium iodide (PI) was used to stain cells with damaged membranes (“dead cells”). Another derivative of the strain (tagged with the firefly luciferase gene [luc]) was used to monitor the metabolic activity of the cell population, since the bioluminescence phenotype is dependent on cellular energy reserves. When the cells were incubated in soil at 28°C, the majority were stained with PI, indicating that they had lost their cell integrity. In addition, there was a corresponding decline in metabolic activity and in the ability to be grown in cultures on agar plates after incubation in soil at 28°C, indicating that the cells were dying under those conditions. When the cells were incubated in soil at 5°C, by contrast, the majority of the cells remained intact and a large fraction of the population remained metabolically active. A similar trend towards better cell survival at lower temperatures was found in pure-culture experiments. These results make A. chlorophenolicus A6 a good candidate for the treatment of chlorophenol-contaminated soil in cold climates.