Z25, a novel intronic snoRNA encoded in mammalian nucleolin gene

A novel intronic small nucleolar RNA ( snoRNA) , termed Z25, was identified from mammals by-computer analysis and experimental sequence methods. Z25 is a 69 nucleotides long RNA containing typical boxC/D motifs, terminal stem and an 11-nucleotide sequence complementary to 18S rRNA. In theory, Z25 functions as an RNA guide for the 2'-0-ribose methylation of adenine at position 1678 (human 18S rRNA coordinate) in 18S rRNA. Z25 snoRNA gene was found to be located in the fifth intron of nucleolin gene of human, mouse and rat, demonstrating that the mammalian nucleoline gene is a host gene encoding multiple snoRNAs.     

Two closely linked rice U14 boxC/D snoRNAs

By analysis of the conserved elements in yeast U14 boxC/D snoRNA. the conserved elements in rice U14 boxC/D snoRNA have been speculated. Through computer search of the international rice genome database, two rice U14 snoRNA gene candidates are obtained. These two putative U14 snoRNA genes are closely linked on rice chromosome 2. The coding sequences of these two snoR-NAs exhibit the hallmark structure of boxC/D antisense snoRNA. They both have conserved boxC and boxD sequences and a 14nt-long complement to the sequence between 414nt and 427nt of rice 18S rRNA (according to GenBank accession no. X00755). The experimental evidence shows that these two snoRNAs are involved in the methylation of the complementary sequence of rice 18S rRNA. The existence and localization of these two snoRNAs are proved by RT-PCR and Northern blot. Further analysis shows that both of the newly found rice snoRNAs have high homology with maize U14 snoRNA. and they are named rice U14.1 snoRNA and U14.2 snoRNA respectively. The gene sequence encoding these two snoRNAs has been deposited in the GenBank database under accession number of AF332622.     

Identification and functional analysis of a novel box C／D snoRNA from Schizosaccharomyces pombe

By constructing and screening the Schizosaccharomyces pombe nuclear cDNA library, a novel small nucleolar RNAs (snoRNA) was identified. The novel snoRNA displays structural features typical of C/D box snoRNA family and possesses a 10-nt-long rRNA antisense element which is predicted to guide the 2‘-O-methylation of the fission yeast 25S rRNA at G940. As expected, the rRNA ribose-methyla- tion site predicted by the novel snoRNA was precisely mapped by a deoxynucleoside triphosphate concentration-dependent primer extension assay. The comparison of functional element of guide snoRNAs among eukaryotes reveals that the novel snoRNA is a partial counterpart of the budding yeast snR60 and was termed snR60-11, snR60-Ⅱ gene nested in the intron of a non-coding RNA gene with an unknown function, which is the first example of a yeast snoRNA encoded in an intron of a non-coding RNA gene. Furthermore, a number of yeast snR60 homologues were also identified from other fungi and fly. Our results reveal that snR60 exhibits diverse genomic organization in eukaryotes, implying the high mobility of snR60 gene in the course of evolution.     

Identification and functional analysis of 23 novel box C／D snoRNAs from Oryza sativa

In a cDNA library generated from rice small nuclear RNAs,30box C/D small nucleolar RNAs (snoRNAs) were identiffied through preliminary screen.Except 7 known snoRNAs such as U14,all snoRNAs were identified in rice for the first time experimentally.Among the 23 novel snoRNAs,11 snoRNAs appear rice-specific,6 snoRNAs are unique to plants,the remaining 6 snoRNAs have their counterparts in both Arabidopsis and yeast or mammals according to the conserved antisense sequencs that guide 2‘-O-ribose methylation of rRNA,17 of the 23 novel snoRNAs were predicted to guide 24 2‘‘-O-ribose methylations at the specificsites of rice 5.8S,18S,25S rRNAs,among which 19 methylated sites were determined by primer extension at low dNTP concentrations.The remaining 6 snoRNAs devoid of rRNA antisense elements may represent novel snoRNA species in rice.The results show that constructing a cDNA library from small nuclear RNAs is an effective experimental approach for novel snoRNA is identification.The novel snoRNAs are important in elucidating the genomic organization and expression of plant snoRNA genes and the mechanism through which 2‘‘-O-ribose methylations took place in rRNAs.     

Identification and characterization of two novel box H/ACA snoRNAs from Schizosaccharomyces pombe

Ineukaryotes,alargenumberofsmallnucleolar RNAs(snoRNAs)accumulatedwithinthenucleolus playimportantrolesinprecursorribosomalRNA(pre RNA)processingandmaturation[1].AllsnoR NAs,withtheexceptionofRNaseMRP,canbe broadlydividedintotwoexpendinggroups,boxC/D andH/ACAsnoRNAs,basedonconservedsequence elements[2].BoxC/DsnoRNAscontaintwocon servedshortsequencemotifs,boxC(UGAUGA)and boxD(CUGA),locatedonlyafewnucleotidesaway fromthe5′and3′ends,respectively,generallyas partofatypical5′3…     

粟酒裂殖酵母snR41 snoRNA的鉴定及其结构进化的意义

采用计算机分析和分子生物学实验的方法,在粟酒裂殖酵母Schizosaccharomyces pombe中发现和鉴定了一种新的反义snoRNA,命名为snR41,与酿酒酵母Sacharomyces cerevisiae snR41同源分子比较,粟酒裂殖酵母snR41只具有一个指导rRNA核糖甲基化的反义序列,这一发现进一步揭示了反义snoRNA同源分子在一级结构上的多样性,为研究反义SnoRNA结构及进化提供了新的线索。     

A large nucleolar U3 ribonucleoprotein required for 18S ribosomal RNA biogenesis

Although the U3 small nucleolar RNA (snoRNA), a member of the box C/D class of snoRNAs, was identified with the spliceosomal small nuclear RNAs (snRNAs) over 30 years ago, its function and its associated protein components have remained more elusive. The U3 snoRNA is ubiquitous in eukaryotes and is required for nucleolar processing of pre-18S ribosomal RNA in all organisms where it has been tested. Biochemical and genetic analyses suggest that U3 pre-rRNA base-pairing interactions mediate endonucleolytic pre-rRNA cleavages. Here we have purified a large ribonucleoprotein (RNP) complex from Saccharomyces cerevisiae that contains the U3 snoRNA and 28 proteins. Seventeen new proteins (Utp1 17) and Rrp5 were present, as were ten known components. The Utp proteins are nucleolar and specifically associated with the U3 snoRNA. Depletion of the Utp proteins impedes production of the 18S rRNA, indicating that they are part of the active pre-rRNA processing complex. On the basis of its large size (80S; calculated relative molecular mass of at least 2,200,000) and function, this complex may correspond to the terminal knobs present at the 5' ends of nascent pre-rRNAs. We have termed this large RNP the small subunit (SSU) processome.     

醇酒酵母反义snoRNA一级结构的分析

对酿酒酵母Saccharomyces cerevisiae基因组中发现和鉴定的41个反义snoRNA进行一级结构的分析表明：酿酒酵母snoRNA基因富含AT：41个反义snoRNA全都有boxC'和boxD'结构元素；根据反义snoRNA保守结构元素及反义序列的数目和位置的特点，将反义snoRNA分为5种结构类型，认为snoRNA具有两个主要的功能区；在snR57、snR59、snR71和snR75不具有指导甲基化反义序列的功能区中，发现有一段长10－12个核苷酸的序列与rRNA互补，为进一步研究反义snoRNA的结构与功能提供了重要线索。     

酵母snoRNA基因簇启动子的比较分析

报道对酿酒酵母ｓｎｏＲＮＡ基因簇启动子序列的研究结果．通过计算机分析,发现酿酒酵母中Ｚ２Ｚ８和ＳｎＲ１９０Ｕ１４ｓｎｏＲＮＡ基因簇有相似的启动子结构．这两个ｓｎｏＲＮＡ基因簇都是由一个上游的启动子负责整个基因簇的转录,产生多个顺反子ｓｎｏＲＮＡ的前体,然后再加工成熟为各个独立的ｓｎｏＲＮＡ．在启动子保守序列ＴＡＴＡｂｏｘ的上游还发现２个ＲＡＰ１序列,表明ｓｎｏＲＮＡ基因簇的表达可以通过ＲＡＰ１元素与核糖体蛋白基因的表达协同调控．这是在ｓｎｏＲＮＡ基因的启动子中首次发现ＲＡＰ１调控元素．对ｓｎｏＲＮＡ基因簇的进化特点也进行了讨论．     

1A6/DRIM,the human UTP20 functions in 28S and 5.8S rRNA processing

1A6/DRIM has been identified as UTP20, a small subunit processome component, functioning in 18S rRNA processing. In the present study, the maturation of 28S rRNA and 5.8S rRNA was inhibited when 1A6/DRIM was silenced in HeLa cells; and coin-cidently, an accumulation of 32S rRNA precursor was observed. Immunoprecipitation was performed with the anti-1A6/DRIM antibody, followed by Northern blot with the ITS2 probe. The results showed that 1A6/DRIM was associated with both 32S and 12S rRNA precursors in vivo. The expression profile of 1A6/DRIM during rRNA processing was investigated by sucrose density gradient fractionation in combination with Western blot analysis. The results demonstrated that 1A6/DRIM was involved in the pre-60S particles in addition to the pre-40S particles and co-sediment with the 32S and 12S rRNA precursors in the nucleolus. Furthermore, the interaction of U8 snoRNA with 1A6/DRIM was revealed by immunoprecipitation. These results demonstrated that 1A6/DRIM interacted with both 32S rRNA and U8 snoRNA, being involved in 28S rRNA and 5.8S rRNA processing.     

不同饵料投喂对魁蚶幼体生长的影响

【目的】探讨在魁蚶苗种繁育中如何选择合适的饵料,了解魁蚶幼体生物学特性。【方法】选取金藻、角毛藻、海洋酵母、小球藻等4种不同饵料对魁蚶幼体进行为期13d的喂养,测定其壳长、壳高等生物学指标,计算特定生长率,分析不同饵料投喂对魁蚶幼体生长的影响。【结果】从D形幼虫发育到壳顶期这段时期内,混合饵料金藻+海洋酵母较单一饵料投喂魁蚶幼虫的效果好。不同饵料投喂下魁蚶幼虫特定生长率大小依次为金藻+海洋酵母处理组金藻处理组海洋酵母处理组金藻+角毛藻处理组角毛藻处理组小球藻处理组,各处理组间差异极显著(P0.05)。【结论】在魁蚶幼体培育阶段,最佳饵料是金藻+海洋酵母。在没有混合饵料的前提下,金藻效果最好,适合做幼虫的开口饵料;小球藻效果最差,不合适做单一饵料投喂幼虫。     

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…     

四种植物25S rRNA sarcin/ricin结构域甲基化核苷的分析

应用不同浓度的dNTP逆转录反应，分析丁苦瓜、丝瓜、蓖麻和水稻的25SrRNA sarcin/ricin区域中的甲基化核苷，发现了这4种植物25SrRNA的第3023、2966和2962位的腺嘌呤、胸腺嘧啶和腺嘌呤是2’-0-甲基化核苷；在丝瓜和苦瓜25SrRNA的第2992、2990位的胞嘧啶和鸟嘿吟是葫芦科植物所特有的两个2’-0—甲基化核苷；第2994位点的尿嘧啶是苦瓜、丝瓜、蓖麻和水稻的一个碱基甲基化核苷；而且，植物25SrRNA第3023位甲基化腺嘌呤核苷刚好位于sarcin/ricin结构域的茎环上，与核糖体失活蛋白切割位点相距仅5个核苷酸，而在哺乳动物和酵母的rRNA相同位点上没有甲基化修饰的存在，根据这一结果推测，RIPS来源植物核糖体RNA的自我保护可能与这一位点的修饰有关。     

越南槐与多叶越南槐的叶形态研究

【目的】为了快速准确鉴别越南槐(Sophora tonkinensis Gapnep.)与其变种多叶越南槐(Sophora tonkinensis Gapnep.var.polyphylla S.Z.Huang et Z.C.Zhou),对这两个物种的叶形态特征进行比较研究。【方法】通过性状鉴别法和显微鉴别法,对越南槐和多叶越南槐的叶形态进行观察和比较,并利用扫描电镜和体式显微镜分别对叶脉和叶片表皮进行显微观察和微形态研究。【结果】越南槐和多叶越南槐的叶形态可从叶片形状、叶片大小、叶片数目、叶被毛、叶脉的一级脉和二级脉、叶片表皮的蜡质和角质层等特征加以区别。【结论】叶片数目和叶被毛为首要分类性状,可快速鉴别越南槐和多叶越南槐的成年植株;叶脉和叶表皮的微形态可以作为较好的分类和鉴别依据,再结合其他形态特征可准确鉴别包括幼年植株在内的越南槐和多叶越南槐;本文结果支持《广西中药材标准》(1990年版)及《全国中草药汇编》(1996年版)中对中药材山豆根基源种越南槐和多叶越南槐的划分。     

海绵Pseudoceratina sp.共栖细菌多样性及其抑制甘蔗鞭黑粉菌活性研究

【目的】探讨广西斜阳岛附近海域海绵共附生细菌的多样性,并筛选对甘蔗鞭黑粉菌有抑制作用的活性物质,为发现潜在的细菌新物种及开发农用生防菌肥奠定基础。【方法】采用稀释涂布法,通过6种复合营养分离培养基,从海绵Pseudoceratina sp.中分离可培养的共附生细菌。采取细菌形态学观察去除冗余,通过PCR扩增菌株的16SrRNA基因序列,并通过构建系统发育树分析物种多样性。采用牛津杯法进行抑制甘蔗鞭黑粉菌活性筛选实验。【结果】从海绵Pseudoceratina sp.中共分离到可培养细菌54株,经16SrRNA基因序列对比后,获得24株细菌,隶属于13科14属。其中,菌株BGMRC 2118与已发表有效菌株的16SrRNA基因序列的最高相似率为96.46%,可能为潜在新种。抑菌筛选实验结果显示,有8株细菌的发酵粗提物对甘蔗鞭黑粉菌具有很强的抑菌活性。【结论】广西斜阳岛附近海域中海绵共附生细菌具有较高的物种多样性,蕴藏着丰富的新物种资源,富含生物活性菌株。     

Habitat-induced reciprocal transformation in the root phenotype of Oriental ginseng is associated with alteration in DNA methylation

Oriental ginseng is an important medicinal plant that grows in 2 major forms or ecotypes, wild and domesticated. Each form differs conspicuously in root phenotype, but can be converted from one type to another by habitat. Here we show that the habitat-induced transformation of ginseng root phenotype was accompanied by alteration in cytosine methylation at a large number of 5′-CCGG-3′ sites detected by the methylation-sensitive polymorphism (MSAP) marker. The collective CG and CHG methylation levels of all 4 landraces of the domesticated form were significantly lower than those of the wild form. Interestingly, artificially transplanted ginseng plants recreated in both directions the methylation levels (at least in CHG) of their natural counterparts. The methylation differences between the 2 ginseng ecotypes were validated at 2 isolated MSAP loci bearing homology to a 5S rRNA gene or a copia retrotransposon. Our results implicate a link between epigenetic variation and habitat-induced phenotypic flexibility in Oriental ginseng.     

薄层色谱法评价不同产地黄根的品质

【目的】建立评价黄根(Prismatomeris connate Y.Z.Ruan)品质的薄层色谱分析方法。【方法】以有效成分甲基异茜草素为指标,以甲苯-乙酸乙酯-甲醇-甲酸(3∶1∶0.2∶0.1)为展开剂,建立黄根的专属性薄层色谱,并评价10个不同产地黄根的品质。【结果】不同产地黄根药材与对照色谱在相应位置上,显示出相同颜色的斑点,且斑点清晰,比移值(Rf)为0.76。【结论】薄层色谱法能够有效对黄根进行鉴别,且该方法简便、准确,具有较好的适应性。     

柳珊瑚Anthogorgia caerulea相关可培养共生放线菌多样性及其生物毒活性研究

【目的】研究斜阳岛附近海域柳珊瑚Anthogorgia caerulea可培养共生放线菌多样性及其发酵液代谢产物的生物毒活性。【方法】采用纯培养法和基于16SrRNA基因序列的系统发育分析对从广西斜阳岛附近海域采集的柳珊瑚Anthogorgia caeru[ea可培养共生放线菌多样性进行研究,利用卤虫致死法测试其生物毒活性。【结果】从柳珊瑚Anthogorgia caeru[ea中分离获得相关可培养放线菌23株,采用16SrRNA基因序列的系统发育分析后发现,这些菌株属于2个亚纲9个科9个属23种。绝大部分菌株都具有一定的生物毒活性,其中10株菌株有较强生物毒活性,l株有显著毒活性。【结论】广西斜阳岛附近海域柳珊瑚Anthogorgia caeru[ea中存在较为丰富的放线菌多样性,部分菌株具有较强的生物毒活性。