白色假丝酵母氟康唑耐药株的筛选

采用美国国家临床实验标准化委员会(NCCLS)推荐的最小抑菌浓度(MIC)测定方法,从保藏的50多株白色假丝酵母(Candida albicans)(均分离自临床病人)中挑选出两株氟康唑(FCZ)敏感株:编号为BMU8945(MIC值为0.125μg/ml)和BMU8977(MIC值为0.25μg/ml)。同时选择一株白色假丝酵母ATCC14053(MIC值为0.5μg/ml)作为实验原始菌株。经紫外线(UV)和硫酸二乙酯(DES)诱变后,获得近千个FCZ耐药突变菌落(MIC值在64μg/ml以上)。经传代培养,突变茵落的耐药特性能稳定遗传。     

Highly efficient strategy for enhancing taxoid production by repeated elicitation with a newly synthesized jasmonate in fed-batch cultivation of Taxus chinensis cells

A highly efficient bioprocessing strategy was developed for enhancing the production of plant secondary metabolites by repeatedly eliciting a fed-batch culture with a newly synthesized powerful jasmonate analog, 2,3-dihydroxypropyl jasmonate (DHPJA). In suspension cultures of a high taxuyunnanine C (Tc)-producing cell line of Taxus chinensis, 100 microM DHPJA was added on day 7 to fed-batch cultures with feeding of 20 g L(-1) sucrose on the same day. The synergistic effect of elicitation and substrate feeding on Tc biosynthesis was observed, which resulted in higher Tc accumulation than that by elicitation or sucrose feeding alone. More interestingly, both specific Tc yield (i.e., Tc content) and volumetric yield was further improved by a second addition of 100 microM DHPJA (on day 12) to the fed-batch cultures. In particular, with repeated elicitation and sucrose feeding the Tc volumetric yield was increased to 827 +/- 29 mg L(-1), which was 5.4-fold higher than that of the nonelicited batch culture. Furthermore, the above novel strategy was successfully applied from shake flask to a 1-L airlift bioreactor. A high Tc production and productivity of 738 +/- 41 mg L(-1) and 33.2 +/- 1.9 mg L(-1) d(-1), respectively, was achieved, which is higher than previous reports on Tc production in bioreactors. The results suggest that the aforementioned bioprocessing strategy may potentially be applied to other cell culture systems for efficient production of plant secondary metabolites.     

土壤重金属污染对蚯蚓的急性毒性效应研究

测定了草甸棕壤条件下 ,Cu、Zn、Pb、Cd单一 /复合污染对蚯蚓的急性致死及亚致死效应 .结果表明 ,Cu、Pb浓度与蚯蚓死亡率显著相关 (α=0 .0 5 ,RCu=0 .86 ,RPb=0 .87) ,Cu浓度与生长抑制率显著相关 (α=0 .0 5 ,RCu=0 .84) ,其他供试重金属浓度与蚯蚓死亡率和生长抑制率相关性不显著 .蚯蚓个体对重金属毒性的耐受程度差别较大 .其毒性阈值 (引起个体蚯蚓死亡浓度 )分别为 :Cu 30 0mg·kg-1,Zn 130 0mg·kg-1,Pb 170 0mg·kg-1,Cd 30 0mg·kg-1.LC50 分别为 :Cu 40 0～ 45 0mg·kg-1,Zn15 0 0～ 190 0mg·kg-1,Pb2 35 0～ 2 40 0mg·kg-1,Cd 90 0mg·kg-1.在Cu、Zn、Pb、Cd单一污染引起 >10 %蚯蚓死亡的浓度下 ,复合污染导致 10 0 %蚯蚓死亡 ,表明复合污染极强的协同效应 .     

芘在土壤中的共代谢降解研究

高分子量多环芳烃（PAHs)的降解通常以共代谢方式进行,研究比较了高分子量多环芳烃代表种类芘作为唯一C源和能源的降解过程和有共代谢底物存在下的降解过程,结果表明,25d后前者中芘的降解率57％,而后者中芘的降解率为80％,且有共代谢底物存在下,芘在降解过程中关衰期缩短;水扬酸,邻苯二甲酸,琥珀酸钠能作为共代谢底物提高芘的降解率,琥珀酸钠效果最好,芘和低要子量多环芳烃之间也有共代谢关系,菲促进了芘的降解,但萘未出现同样的结果,此外,这阐明了共代谢原理和适宜作高分子量多环芳烃共代谢底物的物质。     

There are abundant antimicrobial peptides in brains of two kinds of Bombina toads

It is well-known that there is a large amount of antimicrobial peptides in amphibian skins but few antimicrobial peptides are found in amphibian brains. Twenty-two and four antimicrobial peptides were purified and characterized from the brain homogenate of Bombina maxima and B. microdeladigitora, respectively. One hundred fifty-eight cDNA clones encoding 79 antimicrobial peptides were isolated from brain cDNA libraries of B. maxima and B. microdeladigitora. These antimicrobial peptides belong to two peptide groups (maximin and maximin-H). Twenty of them are identical to previously reported antimicrobial peptides (maximin 1-8, 10, 11, maximin H1, 3-5, 7, 9, 10, 12, 15, 16) from B. maxima skin secretions. Fifty-nine of them are novel antimicrobial peptides. Some of these antimicrobial peptides showed strong antimicrobial activities against tested microorganism strains including Gram-positive and -negative bacteria and fungi. The current diversity in peptide coding cDNA sequences is, to our knowledge, the most extreme yet described for any animal brains. The extreme diversity may give rise to interest to prospect the actual functions of antimicrobial peptides in amphibian brains.     

环境因子对厌氧微生物脱卤的影响研究进展

有机卤代物在工农业生产中的广泛应用及不合理处置与排放导致其成为地下环境中普遍存在的一类污染物,严重威胁地下生态系统功能、饮用水安全和人类健康。有机卤呼吸细菌在有机卤污染场地的原位生物修复中起到了至关重要的作用。本文简要概述了影响和制约有机卤呼吸微生物生长代谢及脱卤活性的一些关键环境因子,如pH、温度、盐度、电子供受体和氧气等,并且对有机卤呼吸细菌未来的研究方向提出展望,以期为污染场地原位生物修复工程的有效实施提供理论与技术参考。     

A review on the cognitive function of information structure during language comprehension

During communication, information structure can be used to highlight the most relevant piece of information, so that sufficient amount of attention can be allocated to the most important information. This paper aims to review the cognitive function of information structure during language comprehension from a neurocognitve perspective. First, we gave a brief introduction to the concept of information structure that has been studied mostly in linguistic field. Then we introduced recent studies on information structure using electrophysiological and neuroimaging techniques. After that, we discussed the relationship between attention and language processing more generally. Finally, we discussed potential directions for future studies.     

Ecotoxicity of soils contaminated with industrial and domestic wastewater in western Shenyang, China

Soil samples were collected from 7 sites in the up-, mid- and down-reach along and nearby the wastewater irrigation channel, western Shenyang of China. The concentrations of selected pollutants (mineral oil, PAHs - polycycle aromatic hydrocarbons and Cd) were determined by UV spectrometer, HPLC and AAS (atomic adsorption spectrometer) spectrometer, respectively. Toxicity effects of soils were evaluated by seedling emergence test with root length of wheat as the end-point and by earthworms test with the mortality rate and inhibition rates of body weight as endpoints. Results showed accumulation of pollutants for most soils with concentration of 200.2 mg·kg-1-1600 mg·kg-1 for mineral oil, 0.33 mg·kg-1-1.81 mg·kg-1 for Cd and 900.16 mg·kg-1 -2737.91 mg·kg-1 for PAHs. The inhibition rates of root elongation were from -20% up to 40 %, and mortality rates of earthworms ranged from 0%-40% from the exposure period of two weeks to eight weeks by sampling interval of two weeks, the inhibition rates of earthw     

How Listeners Weight Acoustic Cues to Intonational Phrase Boundaries

The presence of an intonational phrase boundary is often marked by three major acoustic cues: pause, final lengthening, and pitch reset. The present study investigates how these three acoustic cues are weighted in the perception of intonational phrase boundaries in two experiments. Sentences that contained two intonational phrases with a critical boundary between them were used as the experimental stimuli. The roles of the three acoustic cues at the critical boundary were manipulated in five conditions. The first condition featured none of the acoustic cues. The following three conditions featured only one cue each: pause, final lengthening, and pitch reset, respectively. The fifth condition featured both pause duration and pre-final lengthening. A baseline condition was also included in which all three acoustic cues were preserved intact. Listeners were asked to detect the presence of the critical boundaries in Experiment 1 and judge the strength of the critical boundaries in Experiment 2. The results of both experiments showed that listeners used all three acoustic cues in the perception of prosodic boundaries. More importantly, these acoustic cues were weighted differently across the two experiments: Pause was a more powerful perceptual cue than both final lengthening and pitch reset, with the latter two cues perceptually equivalent; the effect of pause and the effects of the other two acoustic cues were not additive. These results suggest that the weighting of acoustic cues contributes significantly to the perceptual differences of intonational phrase boundary.