Structure and analysis of phospholipase D gene from Ricinus communis L

Phospholipase D (PLD; EC 3.1.4.4) has been proposed to play a pivotal role in various cellular processes, but molecular understanding of this enzyme is rather limited. This report describes the nucleotide sequence, structure, and genomic organization of a PLD gene from castor bean (Ricinus communis L. cv. Hale). The PLD gene was isolated from a castor bean genomic library using the PLD cDNA as a hybridization probe. Sequence comparison with the PLD cDNA revealed that the PLD gene consisted of four exons and three introns, one of which interrupts the 5-untranslated region. Southern blot analysis indicated that the cloned PLD gene was present as a single-copy gene, and yet there were other PLD or PLD-related sequences in the castor bean genome.     

The genetic basis for indole-diterpene chemical diversity in filamentous fungi

Indole-diterpenes are a structurally diverse group of secondary metabolites with a common cyclic diterpene backbone derived from geranylgeranyl diphosphate and an indole group derived from indole-3-glycerol phosphate. Different types and patterns of ring substitutions and ring stereochemistry generate this structural diversity. This group of compounds is best known for their neurotoxic effects in mammals, causing syndromes such as ‘ryegrass staggers’ in sheep and cattle. Because many of the fungi that synthesise these compounds form symbiotic relationships with plants, insects, and other fungi, the synthesis of these compounds may confer an ecological advantage to these associations. Considerable recent progress has been made on understanding indole-diterpene biosynthesis in filamentous fungi, principally through the cloning and characterisation of the genes and gene products for paxilline biosynthesis in Penicillium paxilli. Important insights into how the indole-diterpene backbone is synthesised and decorated have been obtained using P. paxilli mutants in this pathway. This review provides an overview of these recent developments.     

RT-PCR克隆甜菜硝酸还原酶cDNA全长序列及分析

根据GenBank中已公布的甜菜（Beta vulgaris）硝酸还原酶（nitrate reductase）基因序列（gb∣ABW05098.1∣）,设计引物,以50 mmol·L^-1 KNO₃溶液处理的甜菜幼苗为材料,从总RNA中通过RT-PCR分离得到一个硝酸还原酶基因,其cDNA长2 760 bp,包含了完整的基因编码序列,与已公布的硝酸还原酶基因序列相似性达99%。Southern杂交分析表明,硝酸还原酶基因在甜菜基因组中可能以两个拷贝或低拷贝形式存在。根据其编码的氨基酸序列,利用生物信息学预测了其亚细胞定位和蛋白质的三级结构。     

拟南芥白化突变体心口的基因定位与分析

EMS30是拟南芥经甲基磺酸乙酯（EMS）诱变得到的白化突变体。该突变体的叶绿体结构存在严重缺陷,同时伴随叶绿素缺失。遗传分析显示EMS30突变体的突变表型受隐性单基因控制。采用图位克隆的方法对EMS30突变基因进行定位的结果显示,该基因位于拟南芥第一条染色体的分子标记F21M12和F14N23之间的96kb区间内,该区间包含25个基因。通过生物信息学分析发现,该区间内有3个基因定位在叶绿体或与叶绿体发育相关。这些结果有助于该基因的克隆,为阐释叶绿体发育提供线索。     

Identification and characterization of a novel alternative splice variant of mouse GMx33alpha/GPP34

We have cloned and characterized a novel splice variant of mouse GMx33alpha/Golgi-associated protein of 34 kDa (GPP34), hereby designated GMx33alphaV/GPP34V. This splice variant skips the second and third exons, and the resulting frame shift generates a stop codon in the fourth exon. GMx33alphaV/GPP34V is comprised of 81 amino acid residues derived from the N-terminal end of the full length protein and corresponds to approximately one-third of the full length GMx33alpha/GPP34 sequence with a calculated molecular mass of 8900. In contrast to GMx33alpha/GPP34 mRNA which is expressed at similar levels in various tissues, GMx33alphaV/GPP34V mRNA was differentially expressed when examined by RT-PCR. Compared to other tissues, skeletal muscle showed relatively strong expression of GMx33alphaV/GPP34V mRNA. This splice variant cDNA was also detected in a human cell line.     

Precursor structure of egg proteins in the coral Galaxea fascicularis

In the egg of the reef coral Galaxea fascicularis, four proteins (named GfEP-1 to -4) are stored in high abundance. In the present study, a cDNA containing a full-length open reading frame for GfEP-1 was cloned, and the translated protein sequence was compared to the N-terminal sequences of GfEP-2, -3, and -4. GfEP-1 and -2 were shown to be generated by processing of a precursor of 1439 amino acids, and GfEP-3 turned out to be a partial fragment of GfEP-2. The precursor protein contained regions which exhibited similarities to vitellogenins (Vgs) in bilaterian animals (oviparous vertebrates and invertebrates including nematodes, arthropods, and molluscs). This study reports the first cloning and characterization of a full-length cDNA encoding a Vg in a non-bilaterian animal, and argues that the emergence of Vg as a precursor of egg yolk proteins predated the divergence of the cnidarian and bilaterian lineages.     

Molecular Characterization of a Bacterial Consortium Enriched from an Oilfield that Degrades Phenanthrene

Characterization of functional and phylogenetic genes was carried out on a bacterial consortium, enriched from a water treatment system of an oilfield, that could use phenanthrene as the sole carbon source. The mixed culture degraded 130 mg phenanthrene l⁻¹ in 16 days, which is significantly faster than previously reported pure cultures. The existence of catabolic genes (nahAc, C23O) in the mixed culture was quantitated by most probable number PCR. The plasmid encoding phenanthrene catabolic genes increased relative to the chromosome genes. Heterogeneous bacteria were present according to both PCR denaturing gradient gel electrophoresis and cloning methods, suggesting the possible existence of cooperation between different biochemical PAH-transforming pathways. Revisions requested 15 December 2005; Revisions received 23 January 2006     

基因工程技术在花卉中的应用

近年来花卉产业得到了蓬勃发展,不断成熟的基因工程技术为花卉的品质改良提供了新的思路,也为花卉产业化发展带来了新的机遇。本文综述了影响植物花色、花型、花期等相关基因及转基因的研究,展望了基因工程技术在花卉育种和产业化应用的发展前景。     

优良水稻品种“明恢63”基因组的cosmid文库

以优良水稻（ＯｒｙｚａｓａｔｉｖａＬ．）品种“明恢６３”为材料,以“ＳｕｐｅｒＣｏｓ１”为载体构建了Ｃｏｓｍｉｄ文库。共获得了４５０００个克隆,平均插入片段大小为４０ｋｂ左右,含插入片段的频率为１００％。该文库的容量约为水稻单倍体基因组的４．２倍。     

pKILLIN: a versatile positive-selection cloning vector based on the toxicity of Killin in Escherichia coli

The invention of DNA cloning over 40 years ago marked the advent of molecular biology. The technique has now become a routine practice in any modern biomedical laboratory. Although positive-selection of recombinants in DNA cloning seems to be superior to blue/white selection based on the disruption of the lacZ gene, it is rarely practiced due to its high background, lack of multiple cloning sites, and inability to express the genes of interest or purify the protein products. Here we report the creation of a new positive-selection cloning vector dubbed pKILLIN, which overcomes all of the above pitfalls. The essence behind its high cloning efficiency is the extreme toxicity and small size of the toxic domain of killin, a recently discovered p53 target gene. Insertion inactivation of killin within the multiple cloning site via either blunt- or sticky-end ligation not only serves as a highly efficient cloning trap, but also may allow any cloned genes to be expressed as His-tagged fusion proteins for subsequent purification. Thus, pKILLIN is a versatile positive-selection vector ideal for cloning PCR products, making DNA libraries, as well as routine cloning and bacterial expression of genes.