On-line monitoring of cell concentration of Perilla frutescens in a bioreactor

This article demonstrates the successful in situ real-time monitoring of the cell concentration of Perilla frutescens in a bioreactor by using a laser turbidimeter. It was found that turbidity measurements at 780 nm with the laser sensor were hardly affected by the red color of the anthocyanin produced by P. frutescens cells, nor by the aeration rate or agitation speed within the ranges investigated. There was an excellent linear relationship, with a correlation coefficient (r(2)) higher than 0.99, between the sensor's response and the cell concentration. The whole growth stage of the cells, i.e., lag, logarithmic, and stationary phases, in bioreactor cultivations, could be satisfactorily estimated on-line by means of the in situ turbidimeter. However, during the declining phase of the cells, an apparent deviation was observed between the on-line estimations and off-line measurements of cell concentrations by dry cell weight, while the wet cell weight could be estimated by the same turbidimeter system. We found that this deviation was caused by a decrease in the cell density due to an increase of the individual cell volume and a decrease of the cell dry weight during the declining phase. (c) 1993 John Wiley & Sons, Inc.     

迎接廿一世纪——记中国无锡第十一届国际植物园协会大会

第十一届国际植物园协会（IABG）大会于1993年9月7日在中国无锡开幕,经苏州、杭州,于9月12日在上海闭幕。9月6日部分与会代表参加了在南京举行的“中国南京国际植物园俱乐部”奠基仪式及江苏省重点实验室南京中山植物园“植物迁地保存实验室”扩建部分开放使用等一系列庆祝活动。参加大会的有来自23个国家和地区的199名代表。大会收到论文74篇,其中板报42篇,大会报告13篇。本次会议的主要议题为“植物园与国家发展”。经过大会报告和交流,明确了世界植物园在继续发挥其保护物种和保护环境的功能之外,必须进一步密切植物园与国家发展的关系。全面发展植物园的十项功能,不仅可以增加植物园对社会的贡献,也有利于提高植物园自身的活力和生存能力。大会选出了以主席岩（木规）邦男,副主席李蔼娃、贺善安、安德列也夫,秘书长艾斯特万为领导核心的新一届理事会。世界植物园两大组织国际植物园协会（IABG）和国际植物园保护组织（BGCI）在无锡签署的合作备忘录标志着国际植物园运动进入了一个新的历史时期。理事会的第一次会议于9月11日在由杭州开往上海的火车上举行。讨论了整顿组织、会员登记、出版IABG通讯及与BGCI合作开展活动等问题。会议确认1994年将在印尼召开IABG-AD第二次会议。第十二届IABG大会将于1     

卡介苗对枯否细胞生物特性影响的免疫细胞化学研究

卡介苗(BCG)是增强肝枯否细胞(KC)抗肝癌细胞作用的最佳免疫制剂之一。本实验是给大鼠BCG后,应用溶菌酶免疫细胞化学法显示KC,以图象分析系统测定KC的数量、分布和面积,以细胞分光光度计测定KC溶菌酶活性;分离KC体外受BCG作用后,用ELISA法测定RC的Fc受体表达。结果显示:BCG使KC数量增多一倍,尤以肝小叶周边带为显著;KC体积明显增大,细胞面积增大55.71％,周边带KC面积增大一倍上;细胞溶菌酶光密度增大64.35％;Fc受体表达增强64.82％。上述结果是BCG增强KC抗肝癌细胞作用有关细胞学机制。     

药用寄生植物菟丝子属,列当属和无根藤属氨基酸的分析

本文测定了菟丝子属、列当属和无根藤属某些种的种子和植株氨基酸的种类组成和含量。结果表明,3个属种子和植株氨基酸均在15种以上,且含量丰富,特别是必需氨基酸的含量较高。文中讨论了氨基酸的药用和在种子鉴定与化学分类上的作用,探讨了开发应用的前景。     

UreB immunodominant epitope-specific CD8+ T-cell responses were beneficial in reducing gastric symptoms in Helicobacter pylori-infected individuals

Background and aims

Although Helicobacter pylori is recognized as an extracellular infection bacterium, it can lead to an increase in the number of CD8⁺ T cells after infection. At present, the characteristics of H. pylori antigen-specific CD8⁺ T cells and the epitope response have not been elucidated. This study was focused on putative protective antigen UreB to detect specific CD8⁺ T-cell responses in vitro and screen for predominant response epitopes.

Methods

The PBMCs collected from H. pylori-infected individuals were stimulated by UreB peptide pools in vitro to identify the immunodominant CD8⁺ T-cell epitopes. Furthermore, their HLA restriction characteristics were detected accordingly by NGS. Finally, the relationship between immunodominant responses and appearance of gastric symptoms after H. pylori infection was conducted.

Results

UreB-specific CD8⁺ T-cell responses were detected in H. pylori-infected individuals. Three of UreB dominant epitopes (A-2 (UreB_443–451: GVKPNMIIK), B-4 (UreB_420–428: SEYVGSVEV), and C-1 (UreB_5–13: SRKEYVSMY)) were firstly identified and mainly presented by HLA-A*1101, HLA-B*4001 and HLA-C*0702 alleles, respectively. C-1 responses were mostly occurred in H. pylori-infected subjects without gastric symptoms and may alleviate the degree of gastric inflammation.

Conclusions

The UreB dominant epitope-specific CD8⁺ T-cell response was closely related to the gastric symptoms after H. pylori infection, and the C-1 (UreB_5-13) dominant peptides may be protective epitopes.     

好氧反硝化细菌及其在微污染水源水修复中的应用研究进展

相比于氨氮,天然水体中的硝酸盐氮通常更稳定,导致更难将其从水中去除。由于好氧反硝化可以在有氧环境下进行反硝化作用去除硝酸盐氮,该过程对含有较高溶解氧的天然水体中硝酸盐氮处理有重要作用。本文综述了好氧反硝化菌的分离纯化现状、微生物代谢机制和环境影响因子,并介绍了功能菌群在微污染饮用水源水生物修复的应用研究进展。与一般的厌氧反硝化类似,好氧反硝化菌的种属分布较广,常见的如假单胞菌属(Pseudomoas)、产碱杆菌属(Alcaligenes)、副球菌属(Paracoccus)和芽孢杆菌属(Bacillus)等所属部分微生物均有好氧反硝化能力。大部分好氧反硝化菌株在最佳生长条件下(25–37℃、溶解氧浓度为3–5mg/L、pH为7–8、碳氮比为5–10)具有高效的脱氮效率。但目前好氧反硝化作用在微污染饮用水源水的生物修复方面的应用仍有着脱氮性能不稳定、菌剂流失等不足。此外,目前较少相关中试及实际工程应用的研究,需要进一步的深入探究。     

The distribution of coastal fish eDNA sequences in the Anthropocene

Aim

Coastal fishes have a fundamental role in marine ecosystem functioning and contributions to people, but face increasing threats due to climate change, habitat degradation and overexploitation. The extent to which human pressures are impacting coastal fish biodiversity in comparison with geographic and environmental factors at large spatial scale is still under scrutiny. Here, we took advantage of environmental DNA (eDNA) metabarcoding to investigate the relationship between fish biodiversity, including taxonomic and genetic components, and environmental but also socio-economic factors.

Location

Tropical, temperate and polar coastal areas.

Time period

Present day.

Major taxa studied

Marine fishes.

Methods

We analysed fish eDNA in 263 stations (samples) in 68 sites distributed across polar, temperate and tropical regions. We modelled the effect of environmental, geographic and socio-economic factors on α- and β-diversity. We then computed the partial effect of each factor on several fish biodiversity components using taxonomic molecular units (MOTU) and genetic sequences. We also investigated the relationship between fish genetic α- and β-diversity measured from our barcodes, and phylogenetic but also functional diversity.

Results

We show that fish eDNA MOTU and sequence α- and β-diversity have the strongest correlation with environmental factors on coastal ecosystems worldwide. However, our models also reveal a negative correlation between biodiversity and human dependence on marine ecosystems. In areas with high dependence, diversity of all fish, cryptobenthic fish and large fish MOTUs declined steeply. Finally, we show that a sequence diversity index, accounting for genetic distance between pairs of MOTUs, within and between communities, is a reliable proxy of phylogenetic and functional diversity.

Main conclusions

Together, our results demonstrate that short eDNA sequences can be used to assess climate and direct human impacts on marine biodiversity at large scale in the Anthropocene and can further be extended to investigate biodiversity in its phylogenetic and functional dimensions.     

The vacuolar H+-ATPase of Saccharomyces cerevisiae is required for efficient copper detoxification,mitochondrial function,and iron metabolism

Mutations in the GEF2 gene of the yeast Saccharomyces cerevisiae have pleiotropic effects. The gef2 mutants display a petite phenotype. These cells grow slowly on several different carbon sources utilized exclusively or primarily by respiration. This phenotype is suppressed by adding large amounts of iron to the growth medium. A defect in mitochondrial function may be the cause of the petite phenotype: the rate of oxygen consumption by intact gef2 cells and by mitochondrial fractions isolated from gef2 mutants was reduced 60%–75% relative to wild type. Cytochrome levels were unaffected in gef2 mutants, indicating that heme accumulation is not significantly altered in these strains. The gef2 mutants were also more sensitive than wild type to growth inhibition by several divalent cations including Cu. We found that the cup5 mutation, causing Cu sensitivity, is allelic to gef2 mutations. The GEF2 gene was isolated, sequenced, and found to be identical to VMA3, the gene encoding the vacuolar H ⁺-ATPase proteolipid subunit. These genetic and biochemical analyses demonstrate that the vacuolar H ⁺-ATPase plays a previously unknown role in Cu detoxification, mitochondrial function, and iron metabolism.     

L-苹果酸产生菌筛选及高产突变株诱变选育

通过广泛收集和分离,获得根霉属(Rhizopus)、曲霉属(Aspergillus)及裂褶菌属(Schizophyllum)等属菌株897株。产酸指示平板上的变色圈测定结果表明,它们中间628株为产酸菌。通过纸层析对产酸菌发酵液酸谱的分析,获得129株L-苹果酸产生菌,经进一步测定发酵液中L-苹果酸的含量,筛选出以葡萄糖为原料,摇瓶发酵140小时,L-苹果酸产率48．37g／L,对糖转化率48．37×10^-2 的菌株LMO2。经初步鉴定,这一菌株为曲霉(Asper-gillus sp.)以LM02作为出发株,采用亚硝基胍、自然污染细菌、甲基磺酸乙酯及紫外线进行诱变处理,选育出葡萄糖为原料,L-苹果酸产率较高的突变抹N1-14、N1-14、NE1412、NU1416及NU1419。其中N1-14 的L-苹果酸产量最高,比出发株提高46．2×10^-2。N1-14 的菌丝生长速度快,产孢能力强,摇瓶发酵葡萄糖140小时,平均L-苹果酸产率为72．53g／L,对糖转化率53．74×10^-2。全发酵液经薄层层析测定,不含黄曲霉毒素。发酵产物分离提纯后,得到白色粉末状结晶,经纸层析、质谱及红外光谱测定,证明为L-苹果酸。     

尖孢镰孢一新硝酸盐营养突变类型与营养体亲和性

从73个尖孢镰孢(Fusarium oxysporum)不同专化型菌株上获得684个硝酸盐营养突变株(nit mutant)。作相关氮源利用试验及亚硝酸反应后,鉴定出一新硝酸盐营养突变类型:亚硝酸盐还原酶结构基因类型,命名为nit8,占总突变株的6.7%。同时被鉴别的还有nit1、nit3和Nit M三种突变类型,它们分别占突变株总数的81.0%,3.8%和8.5%。此外,首次引入一种亚硝酸反应在这类研究中的应用,还提出了互补指数概念与公式来表示nit突变株营养体之间亲和的能力。