The structural diversity of carbohydrate antigens of selected gram-negative marine bacteria

Marine microorganisms have evolved for millions of years to survive in the environments characterized by one or more extreme physical or chemical parameters, e.g., high pressure, low temperature or high salinity. Marine bacteria have the ability to produce a range of biologically active molecules, such as antibiotics, toxins and antitoxins, antitumor and antimicrobial agents, and as a result, they have been a topic of research interest for many years. Among these biologically active molecules, the carbohydrate antigens, lipopolysaccharides (LPSs, O-antigens) found in cell walls of gram-negative marine bacteria, show great potential as candidates in the development of drugs to prevent septic shock due to their low virulence. The structural diversity of LPSs is thought to be a reflection of the ability for these bacteria to adapt to an array of habitats, protecting the cell from being compromised by exposure to harsh environmental stress factors. Over the last few years, the variety of structures of core oligosaccharides and O-specific polysaccharides from LPSs of marine microrganisms has been discovered. In this review, we discuss the most recently encountered structures that have been identified from bacteria belonging to the genera Aeromonas, Alteromonas, Idiomarina, Microbulbifer, Pseudoalteromonas, Plesiomonas and Shewanella of the Gammaproteobacteria phylum; Sulfitobacter and Loktanella of the Alphaproteobactera phylum and to the genera Arenibacter, Cellulophaga, Chryseobacterium, Flavobacterium, Flexibacter of the Cytophaga-Flavobacterium-Bacteroides phylum. Particular attention is paid to the particular chemical features of the LPSs, such as the monosaccharide type, non-sugar substituents and phosphate groups, together with some of the typifying traits of LPSs obtained from marine bacteria. A possible correlation is then made between such features and the environmental adaptations undertaken by marine bacteria.     

南方型紫花苜蓿根系盐胁迫应答转录因子鉴定与分析

转录因子可以调节众多下游基因的表达,在植物抗逆境中起重要的调节作用。为了解析转录因子在南方型紫花苜蓿适应盐胁迫环境的分子机制,以南方型紫花苜蓿Medicago sativa Millennium为材料,以正常培养（WT_ck1）和氯化钠（盐）胁迫（WT_N1）条件下的2个样品根系进行转录组分析,鉴定紫花苜蓿根系盐胁迫应答转录因子基因。同时,随机挑选4个转录因子差异表达基因进行实时荧光定量qRT-PCR（3次重复）,验证转录组测序技术（RNA-Seq）结果的可靠性。结果表明:紫花苜蓿根系在250 mmolL－1氯化钠 胁迫下72 h,共检测到31 907个基因表达量发生了改变,表达量差异达到2倍以上的基因共2 758 个。其中,隶属于38个转录因子家族199个转录因子在盐胁迫下差异表达,上调表达104个,下调表达95个。在各转录因子家族中,盐胁迫应答基因数量最多的是MYB基因家族,其后分别是AP2-EREBP,bHLH,WRKY,NAC和GRAS基因家族,这暗示了紫花苜蓿根系对盐胁迫响应可能是多种转录因子家族共同参与的应答过程。 qRT-PCR分析表明:4个随机选择的基因在胁迫前后的表达特点与表达谱测序结果一致。此外,MsERF-2b,MsbHLH,MsbZIP,MsGRAS,MsNAC,MsMGT-3a和MsWRKY等转录因子被选为与盐胁迫应答相关的候选转录因子。该研究结果为阐明植物对盐胁迫的应答机制提供了新的线索。图3表3参36     

Potassium status and clay mineralogy in ordinary chernozems treated with different rates of potassium fertilizers

The effect of a single instance of potassium fertilization at rates of 0, 70, 140, and 280 kg/ha on the potassium status and clay mineralogy was studied in a field experiment on ordinary chernozems. The content of exchangeable potassium determined by the Maslova method and the potassium potential vary with greatest reliability in response to increasing fertilizer rates. The content of easily exchangeable potassium and the potassium-buffering capacity are insignificantly affected by the application rate of potassium fertilizers. The chernozems under study without fertilization are characterized by a low supply of available potassium. When potassium fertilizers are applied at rates of 70 and 140 kg/ha, the soils pass into the category of unstable or high supply according to different gradation systems. The lower limit of the high or optimal supply category is reached only at the application of 280 kg/ha of potassium fertilizer. However, even in this case, chernozems are characterized by a low potassium supply according to the value of potassium potential and the content of nonexchangeable potassium. A single application of potassium fertilizers does not cause significant changes in the contents of illites in the clay fraction.     

大鲵源迟缓爱德华菌的生物学特性及其感染的病理损伤

[目的]研究引起两养殖场大鲵(Andrias davidianus)以肠炎、腹水为临床特征疫情的病原特性及其病理损伤特点.[方法]对患病大鲵进行细菌分离、形态学观察、生理生化测定、16S rDNA序列分析及毒力相关基因检测,并通过K-B法进行药敏试验和HE染色进行组织病理学观察.[结果]分别从患病大鲵的肝、肾和腹水中分...     

中国植物油产业发展现状、问题及对策研究

在对中国油料作物重新分类的基础上,研究了中国油料生产、植物油加工、贸易和消费状况,分析了中国植物油产业存在的问题。研究表明,受政策的限制,中国油料生产裹足不前,而中国的植物油消费在经济的拉动下却不断增加,这直接导致了中国油料和油脂的大量进口,与此同时,中国的植物油加工业还不断被外资控制,植物油产业风险不断加大。最后提出了促进中国植物油产业健康发展的对策建议。     

The mycological properties of medieval culture layers as a form of soil ‘biological memory’ about urbanization

Background, aim, and scope  The mycological properties of soil can offer information about ancient human–landscape interaction, including urbanization. This preposition has been confirmed in our study of the habitation deposits in the medieval Russian settlements (eighth to fourteenth centuries A.D.). Materials and methods  The mycobiota of profiles of anthropogenically transformed soil of excavated medieval settlements were examined in different climate conditions in the European part of Russia. The fungal biomass and biomass structure were evaluated using luminescent microscopy. The isolation and enumeration of microfungi were performed using the method of serial dilutions of soil samples and plating them out on the number of solid media. The isolation of keratinolytic microfungi was performed by hear-bite technique. Results  It was established that in ancient urban soils, the mycobiota may have properties different from those of zone fungal communities. The examined cultural layers of ancient settlements differ from the horizons of the surrounding natural soils because of a bigger rate of fungal spores in fungal biomass, more mosaic distribution of microfungal communities, different species composition and dominant microfungal species, increased incidence of some ecological, and trophic fungal groups (for example, keratinophilic, potentially pathogenic microfungi). Discussion  The mycological characteristics of anthropogenic deposits in the excavated medieval settlements were found to be mainly similar to mycological properties of modern urban soils. Conclusions  These properties of habitation deposits can be interpreted as a kind of “soil mycological memory” of the ancient urban impact. Recommendations and perspectives  Soil mycological characteristics could be used in paleoecological reconstructions and biomonitoring of urban impacts     

肠炎沙门氏菌鞭毛蛋白基因快速克隆和鉴定

以提纯的肠炎沙门氏菌染色体ＤＮＡ为材料,在一对含有ＣＵＡＣＵＡＣＵＡＣＵＡ的特殊引物引导下,应用ＰＣＲ扩增出鞭毛蛋白基因ｆｌｉＣｇ,ｍ,约１．８ｋｂ左右大小,然后以ＵＤＧ法快速克隆到质粒ｐＡＭＰ１０中,转化第１宿主大肠杆菌ＴＧ１或大肠杆菌ＤＨ５α,在氨苄青霉素平板上筛选转化子,小量制备重组质粒ＤＮＡ,再转入第２宿主大肠杆菌ＬＣ－２ａ（ｈａｇ－,ｒｅｃＡ－）,所有转化子均出现动力。其中的一个克隆ｐＡＭＰ·ＧＭ经动力和动力抑制试验、血清学试验、鞭毛电镜观察及部分序列测定,均证实ｐＡＭＰ·ＧＭ中载有肠炎沙门氏菌鞭毛蛋白基因ｆｌｉＣｇ,ｍ。ｆｉｌＣｇ,ｍ克隆成功为寻求肠炎沙门氏菌防制新方法奠定了基础,研究中建立的快速克隆策略为广泛、深入地开展ｆｌｉＣ研究提供了便捷的新途径。     

中国禽肉对日出口战略研究

日本是中国禽肉的主要出口国,但从2002年开始中国的禽肉对日出口逐年下降,本文通过分析中国禽肉的生产与出口状况、日本禽肉的进口特点以及竞争国巴西、泰国和美国的禽肉出口状况,研究了中国禽肉对日出口过程中的优势和劣势,提出了中国的禽肉出口战略。     

Microbial Communities of Interglacial and Interstadial Paleosols of the Late Pleistocene

Eurasian Soil Science - The taxonomic structure of microbial communities in the Late Pleistocene paleosols of different ages in the Central Russian Upland formed under contrasting climatic...