High variability of the gvpA-gvpC region in Microcystis

Gas vesicles provide buoyancy to Microcystis and other common cyanobacterial bloom-forming species. gvpA and gvpC are structural genes encoding gas vesicle proteins. Phylogenetic analyses of 10 Microcystis strains/uncultured samples showed that gvpC and each intergenic segment of the gvpA-gvpC region can be divided into two types. The combination of different types of gvpC and intergenic segments is an important factor that diversifies this genomic region. Some Microcystis strains isolated in China possess a 172 to 176 bp sequence tag in the intergenic segment between gvpA and gvpC. The gvpA-gvpC region in Microcystis can be divided into at least 4 classes and more numbers of subclasses. Compared to rbcLX and other regions, the high variability of the gvpA-gvpC region should be more useful in identifying geographical isolates or ecotypes of Microcystis.     

A miniature insertion element transposable in Microcystis sp. FACHB 854

A 186-bp sequence with imperfect terminal inverted repeats and target direct repeats but without any transposase-encoding capacity was found to be transposable in an isolate derived from Microcystis sp. FACHB 854. This miniature insertion element, designated as ISM854-1, and with its homologues present at least 10 copies in the genome of Microcystis FACHB 854, is inserted into the 8-bp long and AT-rich target sequences, but none or few in other Microcystis strains. A variant of ISM854-1, denoted ISM854-1A, has perfect inverted repeat sequences and may transpose in pairs in a structure like a composite transposon. This is the first report of non-autonomous transposition of a mini-IS in a cyanobacterium.     

广西金线莲形态多样性及优良类型选择

为筛选出广西金线莲Anoectochilus roxburghii(Wall.)Lindl.优良品种资源,对广西金线莲植株性状特征及无性繁殖后代的遗传稳定性进行观测,并测定有效活性成分(多糖和总黄酮)含量。结果表明,广西金线莲植株形态存在明显差异,主要表现在株型大小、叶形、叶上网脉特征、抗病性、授粉结实等方面。株型大小可分为2个株系;叶片形状可分为2种类型;叶上网脉特征可分为3种类型。根据株型和叶片特征可将广西金线莲划分为10个园艺类型,其中类型GXAR 01具有植株高大,叶形优美,适应性强,多糖、总黄酮含量高等特点,同时具有多代的遗传稳定性,被选为优良类型。广西金线莲优良类型GXAR 01可作为金线莲新品种培育的优质育种材料,也可在产业化生产中直接推广应用。     

气相色谱–离子迁移谱分析微囊藻的挥发性成分

建立顶空–气相色谱–离子迁移谱（headspace-gas chromatography-ion mobility spectrometry,HS-GC-IMS）方法，比较了不同生长时期的微囊藻挥发性物质差异。根据离子迁移谱图结果，结合化学计量学方法对比挥发性有机化合物，通过其指纹谱图观察挥发性物质相对含量的变化规律。结果表明，挥发性成分的GC-IMS谱图存在明显差异，前2个主成分累计贡献率达到78.4%。从微囊藻水华样品中共鉴定出91种挥发性成分，其中包括醛类23种、醇类21种、酯类16种、酮类10种、硫醚类7种、酸类2种、萜烯类2种，其中1-丁醇、(E,E)–2,4–癸二烯醛、乙酸、二甲基硫醚、(E)–3–己烯–1–醇、1–辛烯–3–酮等是微囊藻水华特征挥发性差异物。本方法操作简便快速，灵敏度高，可用于藻类水华时挥发性代谢物的筛查及确证，为环境监测提供数据支持。     

自然发酵乳及传统开菲尔粒中酵母菌的多样性研究

研究自然发酵乳和内蒙古牧区传统开菲尔粒中酵母菌的多样性,目的是探寻酵母菌的主要菌群和种属类型,为筛选可发酵低酒度发酵乳的酵母菌奠定基础。该研究首先进行稀释涂布和划线分离出酵母菌株、然后进行菌落形态和细胞形态的初步分类,再进行5.8SrDNA-ITS区域RFLP分子鉴定,将分离到的130株酵母菌区分为10种形态类型、6种分子类型,分别为马克思克鲁维酵母菌(Kluyveromyces marxianus)、隐球酵母菌(Cryptococcus sp.)、酿酒酵母菌(Saccharomyces cerevisiae)、热带假丝酵母菌(Candida tropicalis)、陆生伊萨酵母菌(Issatchenkia terricola)和季也蒙毕赤酵母菌(Pichia guilliermondii)。其中马克思克鲁维酵母菌、酿酒酵母菌和季也蒙毕赤酵母菌为优势菌群,具有酿造低酒度发酵乳的潜力。     

Comparison of heavy metal accumulation by a bloom-forming cyanobacterium, Microcystis aeruginosa

Microcystis aeruginosa is the dominant species during cyanobacterial blooms in freshwater lakes. In the present study, we compared the bioaccumulation characteristics of cadmium (Cd) and zinc (Zn) in Microcystis cells. In short-term uptake tests, a rapid sorption of Cd and Zn occurred in the first few minutes, with a subsequent slower internalization process. No obvious difference was observed between Zn and Cd in terms of their short-term uptake kinetics. In efflux experiments, elimination of Zn from the cells was faster than that of Cd. In the 72-h exposure tests, the intracellular Cd concentrations increased with exposure time whereas the intracellular Zn concentrations always reached a plateau. The cellular Cd showed greater variation than the cellular Zn at various free Cd²⁺ or Zn²⁺ concentrations. The differences in Cd and Zn accumulation and elimination indicated that Microcystis cells had a higher bioaccumulation capacity for Cd than for Zn. In field studies, the bioconcentration factor (BCF) of Cd in lake-harvested Microcystis was more than 10 times higher than those of other metals. The results of the present study strongly suggested that the bloom-forming Microcystis may affect the Cd transportation and biogeochemical cycling in eutrophic freshwater ecosystems.     

Identification and evolutionary implication of four novel box H/ACA snoRNAs from Giardia lamblia

During the biogenesis of eukaryotic ribosomes, the nascent pre-rRNA undergoes a complex pattern of nu- cleotide modifications of its mature rRNA sequences, including 2′-O-ribose methylation and pseudouridyla- tion, which are critical for the biogenesis a…     

广西植被调查、分类与植被志研编方案

广西是我国植被类型较丰富的省区之一,开展《广西植被志》研编意义重大。本文在全面总结广西植被调查研究历史的基础上,将植被调查研究的进程分为3个阶段：第一阶段为1950-1980年,第二阶段为1981-1999年,第三阶段为2000年至今。对《广西森林》《广西植被志要》和《广西植被(第一卷)》中的植被分类原则、等级、分类结果及各分类系统的特点进行分析比较。在遵循《中国植被志》的研编标准及规范的基础上,提出《广西植被志》的研编方案,建议以植被型组独立成卷,即可分为6卷：森林卷、灌丛卷、草丛卷、沼泽与水生植被卷、农林植被卷、城市植被卷。其中,森林卷可分为6册,即针叶林和针阔叶混交林分册、落叶阔叶林分册、常绿落叶阔叶混交林分册、常绿阔叶林分册、季雨林和雨林分册、竹林分册;灌丛植被、草丛植被和沼泽与水生植被各独立成卷;农林植被卷分为两册,分别是农业植被分册和林业植被分册;城市植被独立成卷。此外,加上第一卷总论,《广西植被志》可由7卷13册组成。对建立10个植被信息数据库及广西数字植被大数据平台提出初步方案。《广西植被志》的研编及出版必将推动广西植被生态科学的进一步发展。     

Characterization of nitrogen-fixing moderate halophilic cyanobacteria isolated from saline soils of Songnen Plain in China

Twenty out of 200 isolates of cyanobacteria mainly from saline soils of Songnen Plain of China were successfully grown on BG11 N-free medium. The nitrogen-fixing activity was then demonstrated for the twenty isolates in modified BG11 medium using the acetylene reduction assay. All of them possessed appreciable nitrogenase activity (acetylene reduction) under non-saline conditions; however, at 5 % NaCl only 60 % of the isolates exhibited a high rate of this activity and 25 % were completely negative under these conditions. The cyanobacteria isolates grew well in BG11 medium; nevertheless, growth of the majority of isolates was reduced by about 25%-85% in the same medium containing 5% NaCl. Cellulolytic activity was detected in 50% of the twenty strains, amylolytic in 45%, and pectinolytic in 10% of the isolates. The cyanobacteria isolates showed also enzymeatic activity under saline conditions (6%). The preliminary identification indicated that seven isolates were Nostoc, two were Microcystis, four were Oscillatoria, six were Anabaena, and one isolate was Synechococcus.      

菠菜转录因子MYB基因家族的鉴定及表达分析

利用生物信息学手段鉴定了76个具有典型R结构的菠菜转录因子（Spinacia oleracea） MYB,其中包括72条R2R3-MYB基因（2R-MYB）和4条R1R2R3-MYB基因（3R-MYB）。通过生物信息学对菠菜MYB转录因子家族成员的理化性质、染色体定位、结构域序列保守性和系统进化关系进行了分析,结果表明：菠菜MYB家族有32个基因位于染色体正链,另外44个基因位于染色体反链;MYB的DNA结合域中的保守域主要位于两个R重复序列的第二和第三螺旋之间,结合域中每个R重复的第一和第二色氨酸之间的氨基酸序列相对不保守;根据菠菜、拟南芥及甜菜的MYB家族系统进化关系可以推测,菠菜MYB家族中56个成员可以按功能划分为4类,在菠菜的生长发育过程中可能起着重要的调节作用,其余成员中有7个MYB基因可能参与菠菜响应氮素浓度的氮素利用及生长发育进程。     

Effects of inorganic arsenic on growth and microcystin production of a <Emphasis Type="Italic">Microcystis</Emphasis> strain isolated from an algal bloom in Dianchi Lake,China

Our previous data have shown that inorganic arsenic concentrations were high in Dianchi Lake, China, where Microcystis blooms often occur. To explore the relationship between arsenic and the growth of Microcystis, the effects of arsenite [As(III)] and arsenate [As(V)] on the growth and toxin production of M. aeruginosa strain FACHB 905 were tested. Results showed that M. aeruginosa FACHB 905 was tolerant to inorganic arsenic and its growth was not inhibited when the concentration of As(III) was below 10⁻⁵ mol L⁻¹ or that of As(V) below 10⁻³ mol L⁻¹. Total microcystin production was stimulated in the presence of 10⁻⁷ mol L⁻¹ As(III) and the response of this M. aeruginosa strain to As(III) seemed to be a typical inverted U-shaped hormesis. The content increase of microcystin-LR per cell indicated that the toxicity was enhanced as M. aeruginosa FACHB 905 was exposed to As(V). Considering the relatively high concentration of inorganic arsenic in Dianchi Lake (139 μg L⁻¹ in epilimnetic water), the origin of the M. aeruginosa strain, inorganic arsenic favors survival of M. aeruginosa FACHB 905 and may stimulate its microcystin production and cellular toxicity.     

Transgenes in F4 pMThGH-transgenic common carp (Cyprinus carpio L.) are highly polymorphic

To gain information on the integration pattern of pMThGH-transgene, 50 transgenes were recovered from F₄ generation of pMThGH transgenic common carp (Cyprinus carpio L.) and 33 recovered genes were analyzed. The restriction maps of these recovered genes were constructed by digestion with five kinds of enzymes. These transgenes can be classified into 4 types according to their restriction maps. Only one type of transgenes maintains its original molecular form, whereas the other three types are very different from the original one and vary each other on both molecular weight and restriction maps. This implies that the sequences of most transgenes have been deleted and/or rearranged during integration and inheritance. The results of PCR amplification and Southern blot hybridization indicate thatMThGH in Type I transgene keeps intact but most of its sequence has been deleted in other three types. All these results suggest that transgenes in F₄ generation of transgenic carp are highly polymorphic. Two DNA fragments concerning integration site of transgenes were cloned from recovered transgenes, and found to be homologous to the 5′UTR ofβ-actin gene of common carp and mouse mRNA for receptor tyrosine kinase (RTK), respectively.     

广西海岸潮间带草本植物群落的研究

【目的】探究广西海岸潮间带草本植物区系和群落类型,为广西滨海湿地的保护与利用提供参考依据。【方法】在广西海岸东段、中段及西段潮间带选择典型的地段作为研究样地,各段设置5~8个样地,采取样方法进行调查,记录组成种类和群落类型,分析植物区系成分,编制群落分类系统。【结果】广西海岸潮间带草本植物群落物种共有29种,隶属10科18属,莎草科、禾本科、水鳖科和丝粉藻科的种类较多;根据中国湿地植被的分类系统和分类原则,结合广西海岸的具体情况,将广西海岸潮间带草本植物群落划分为4个植被型和16个群系。【结论】草本植物科、属的区系成分简单,具有很明显的热带性;潮间带草本植物群落结构简单;高潮区和河口区分布的群落较多。     

《中国药典》中四个品种来源的陈皮挥发油GC-MS分析比较

目的采用主成分分析(PCA)和聚类分析对《中国药典》中四个品种来源的陈皮挥发油GC-MS数据分析比较,鉴别其不同种源。方法对80批次不同品种和不同产地的陈皮样品挥发油进行GC-MS分析,利用其共有成分峰面积数据,采用主成分分析和聚类分析将共有特征峰进行鉴别区分。结果通过主成分分析和聚类分析可将广东新会茶枝柑样品与其它地区样品大致分为两类。结论本方法可用于新会陈皮和其它不同品种来源陈皮的鉴别。     

基于模糊颜色提取的彩色图像分割

为了对彩色图像进行有效分割,提出了一种基于模糊颜色提取的新型彩色图像分割算法,这种算法可以有效的进行区域分割.首先,提出了一种模糊颜色提取方法,然后介绍了该算法,算法经过迭代可以选择典型的种子颜色来提取颜色分量,最后应用区域生长法可以确保所需区域的完整连通性.区别于现有的图像分割方法,本方法是将相同的像素分成几个模糊集,分割成功率提高10%左右.实验结果表明该算法可以合理分割出所需区域,避免冗余,并且具有较好的噪声抑制力和鲁棒性.     

超声探测颈部Ⅵ区淋巴结对诊断桥本氏甲状腺炎的临床研究

目的 通过超声探测发现颈部VI区淋巴结,指导化学发光检测TG-Ab、TPO-Ab,从而探讨超声提示桥本氏甲状腺炎（Hashimoto''s thyroiditis,HT）的可靠性。方法 选择在我院行甲状腺超声检查并发现颈部VI区淋巴结患者108例,常规检测FT3、FT4、TSH、TPO-Ab、TG-Ab,当有感冒咽痛病史及甲状腺区疼痛患者需同时检测血沉（ESR）。怀疑恶性甲状腺结节患者需经手术证实。病例所有资料分成HT组和非HT组,对应VI区所显示的正常和异常淋巴结分析,同时将单纯HT（图像较均一,可有单发典型胶质结节）和声像较均一的单纯非HT对应正常与异常淋巴结另行回顾性分析。结果 不同致病因素所致颈部VI区显示淋巴结,无论HT组或非HT组,颈部VI区超声所显示淋巴结中异常淋巴结回声比例均较高,HT组占97.2%,非HT组占91.9%,相互间无统计学差异（χ²=0.577,P=0.448）。在排除亚急性甲状腺炎、甲状腺恶性肿瘤及炎性结节等其他声像图改变后,颈部VI区异常淋巴结对应的单纯HT组与单纯非HT组相互间有显著差异（χ²=6.126,P=0.013）,超声显示颈部VI区异常淋巴结与临床诊断桥本氏甲状腺炎密切相关,诊断阳性符合率为96%。结论 所有致病因素致超声显示颈部VI区淋巴结中,基本为异常淋巴结回声。在排除其他较典型致病因素后,超声在颈部VI区发现异常淋巴结可以提示诊断桥本氏甲状腺炎。     

波流环境下双孔浮射流运动特性

利用粒子图像测速技术(PIV)对波流环境下双孔浮射流的速度场进行测量,对不同组次的相位平均速度场、时均速度场进行定性描述;通过引入考虑横流、波浪、浮力影响的综合特征长度l_(mb),给出了轴线垂向速度衰减过程分区的定量结果。研究表明,波流作用下会产生污染物云团现象,加快双孔射流速度衰减;波浪的作用能够减弱孔间相互影响;浮力的作用能够减小射流体偏转角度和侧向展宽;无量纲的轴线垂向速度变化可以分为近区(z/l_(mb)3)、过渡区(3z/l_(mb)6)、远区(z/l_(mb)6)3个区段。     

走马胎不同类型材料的继代增殖及生根特征

研究走马胎（Ardisia gigantifolia）不同类型材料对种苗组培快繁中继代增殖和生根诱导的影响,为其规模化生产提供科学依据。以茎段萌发腋芽、叶片诱导不定芽和叶片细小茎段为试验材料,测量记录继代培养的增殖系数、苗高、鲜质量和茎叶生长情况,以及生根培养的生根率、根系和植株生长情况等,并采用隶属函数法分析评价走马胎不同类型材料继代增殖和生根培养情况。研究结果表明：在走马胎继代增殖和生根培养中,腋芽培养效果最好,叶片细小茎段效果最差;在继代增殖中,腋芽培养的各项指标数基本达到叶片诱导不定芽和叶片细小茎段的1.5倍以上,在生根培养中,腋芽培养的各项指标数也达到其他两类材料的1.3倍以上;综合评价排序均为腋芽 > 叶片诱导不定芽 > 叶片细小茎段。腋芽为最佳培养材料,可用于走马胎组培苗工厂化生产。     

<Emphasis Type="Italic">In vitro</Emphasis> induction of mouse meningeal-derived ips cells into neural-like cells

Previous research has shown that mouse embryonic stem (ES) cells can be induced to form neural cells in adherent monocultures. In this study, pluripotent stem (iPS) C5 cells derived from meningeal membranes were converted successfully into neural-like cells using the same protocol generally used for ES cells. Meningeal-iPS C5 cells were induced to express neural markers Sox1, Sox3, Pax6, Nestin and Tuj1 and to reduce the expression of ES markers Oct4 and Nanog during neural differentiation, and can be differentiated into Pax6 and Nestin positive neural progenitors, and further into neuronal, astrocytic, and oligodendrocytic cells. In vitro differentiation of iPS cells into patient-specific neural cells could serve as a model to study mechanisms of genetic diseases and develop promising candidates for therapeutic applications in dysfunctional or aging neural tissues. Meningeal cells express a high level of the embryonic master regulator Sox2, allowing them to be reprogrammed into iPS cells more easily than other somatic cells.