The characterisation of <Emphasis Type="Italic">AOP2</Emphasis>: a gene associated with the biosynthesis of aliphatic alkenyl glucosinolates in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Background  

Glucosinolates, a group of nitrogen and sulfur containing compounds associated with plant-insect interactions, are produced by a number of important Brassicaceae crop species. In Arabidopsis the AOP2 gene plays a role in the secondary modification of aliphatic (methionine-derived) glucosinolates, namely the conversion of methylsulfinylalkyl glucosinolates to form alkenyl glucosinolates, and also influences aliphatic glucosinolate accumulation.     

A comparative map viewer integrating genetic maps for <Emphasis Type="Italic">Brassica</Emphasis> and <Emphasis Type="Italic">Arabidopsis</Emphasis>

Background  

Molecular genetic maps provide a means to link heritable traits with underlying genome sequence variation. Several genetic maps have been constructed for Brassica species, yet to date, there has been no simple means to compare this information or to associate mapped traits with the genome sequence of the related model plant, Arabidopsis.     

Characterizing the stress/defense transcriptome of <Emphasis Type="Italic">Arabidopsis</Emphasis>

Background  

To understand the gene networks that underlie plant stress and defense responses, it is necessary to identify and characterize the genes that respond both initially and as the physiological response to the stress or pathogen develops. We used PCR-based suppression subtractive hybridization to identify Arabidopsis genes that are differentially expressed in response to ozone, bacterial and oomycete pathogens and the signaling molecules salicylic acid (SA) and jasmonic acid.     

Cloning and expression analysis of <Emphasis Type="Italic">GmGAL1</Emphasis>, <Emphasis Type="Italic">SOC1</Emphasis> homolog gene in soybean

A MADS box gene AGL20/SOC1 is a main integrator in Arabidopsis flowering pathway whose structure and function are highly conserved in many plant species. A soybean MADS box gene GmGAL1 (G lycine max A GAMOUS L ike 1) as a homolog of AGL20/SOC1, was cloned from soybean cultivar Kennong18 and its function was investigated in transgenic Arabidopsis lines. Sequence comparisons showed that the closest homolog gene to GmGAL1 is AGL20/SOC1 in Arabidopsis and VuSOC1 in Vigna unguiculata. We investigated the expression level of GmGAL1 using quantitative real-time PCR, and the result showed that GmGAL1 was regulated by a circadian mechanism and its expression oscillated at a cycle of 24 h. The expression level of GmGAL1 was fluctuated in diverse tissues/organs and developmental stages. Considering its expression can be detected in different tissues throughout the life cycle and its protein localized in cytoplasm in Arabidopsis protoplasm, we proposed that GmGAL1 may be a multifunctional gene in the context of the soybean development. Ectopic expression of GmGAL1 in Arabidopsis enhanced flowering under long-day condition and partially rescued soc1 late flowering type.     

Gene gain and loss events in <Emphasis Type="Italic">Rickettsia</Emphasis> and <Emphasis Type="Italic">Orientia</Emphasis>species

Background  

Genome degradation is an ongoing process in all members of the Rickettsiales order, which makes these bacterial species an excellent model for studying reductive evolution through interspecies variation in genome size and gene content. In this study, we evaluated the degree to which gene loss shaped the content of some Rickettsiales genomes. We shed light on the role played by horizontal gene transfers in the genome evolution of Rickettsiales.     

Viable nonsense mutants for the essential gene <Emphasis Type="Italic">SUP45</Emphasis> of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

Background  

Termination of protein synthesis in eukaryotes involves at least two polypeptide release factors (eRFs) – eRF1 and eRF3. The highly conserved translation termination factor eRF1 in Saccharomyces cerevisiae is encoded by the essential gene SUP45.     

Expression and functional analysis of <Emphasis Type="Italic">TaASY1</Emphasis> during meiosis of bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis>)

Background  

Pairing and synapsis of homologous chromosomes is required for normal chromosome segregation and the exchange of genetic material via recombination during meiosis. Synapsis is complete at pachytene following the formation of a tri-partite proteinaceous structure known as the synaptonemal complex (SC). In yeast, HOP1 is essential for formation of the SC, and localises along chromosome axes during prophase I. Homologues in Arabidopsis (AtASY1), Brassica (BoASY1) and rice (OsPAIR2) have been isolated through analysis of mutants that display decreased fertility due to severely reduced synapsis of homologous chromosomes. Analysis of these genes has indicated that they play a similar role to HOP1 in pairing and formation of the SC through localisation to axial/lateral elements of the SC.     

<Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> outer ovule integument morphogenesis: Ectopic expression of <Emphasis Type="Italic">KNAT1</Emphasis>reveals a compensation mechanism

Background  

The Arabidopsis outer ovule integument is a simple two-cell layered structure that grows around the developing embryo and develops into the outer layer of the seed coat. As one of the functions of the seed coat is the protection of the plant embryo, the outer ovule integument is an example for a plant organ whose morphogenesis has to be precisely regulated.     

Evolutionary history of <Emphasis Type="Italic">Wolbachia</Emphasis> infections in the fire ant <Emphasis Type="Italic">Solenopsis invicta</Emphasis>

Background  

Wolbachia are endosymbiotic bacteria that commonly infect numerous arthropods. Despite their broad taxonomic distribution, the transmission patterns of these bacteria within and among host species are not well understood. We sequenced a portion of the wsp gene from the Wolbachia genome infecting 138 individuals from eleven geographically distributed native populations of the fire ant Solenopsis invicta. We then compared these wsp sequence data to patterns of mitochondrial DNA (mtDNA) variation of both infected and uninfected host individuals to infer the transmission patterns of Wolbachia in S. invicta.     

A non-sense mutation in the putative anti-mutator gene <Emphasis Type="Italic">ada/alkA</Emphasis> of <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> and <Emphasis Type="Italic">M. bovis</Emphasis> isolates suggests convergent evolution

Background  

Previous studies have suggested that variations in DNA repair genes of W-Beijing strains may have led to transient mutator phenotypes which in turn may have contributed to host adaptation of this strain family. Single nucleotide polymorphism (SNP) in the DNA repair gene mutT1 was identified in MDR-prone strains from the Central African Republic. A Mycobacteriumtuberculosis H37Rv mutant inactivated in two DNA repair genes, namely ada/alkA and ogt, was shown to display a hypermutator phenotype. We then looked for polymorphisms in these genes in Central African Republic strains (CAR).     

Heterologous expression of a <Emphasis Type="Italic">Ammopiptanthus mongolicus</Emphasis> late embryogenesis abundant protein gene (<Emphasis Type="Italic">AmLEA</Emphasis>) enhances <Emphasis Type="Italic">Escherichia coli</Emphasis> viability under cold and heat stress

A late embryogenesis abundant protein gene, AmLEA from Ammopiptanthus mongolicus, was introduced into Escherichia coli using the IMPACT™-TWIN system to analyze the possible function of AmLEA under heat and cold stresses. A fusion protein about 38 kD was expressed in E.coli cells harboring pTWIN-LEA after the induction of IPTG by SDS–PAGE analysis and the accumulation of the fusion protein peaked 3 h after IPTG addition when cultured at 37°C. Compared with control cells, the E. coli cells expressing AmLEA fusion protein showed improved chilling and heat resistence, illuminating the protein may play a protective role in cells under stress conditions. These results suggested the natively unstructured protein, similar to other members of LEA proteins, has high capacity for binding water and potential protective function against dehydration or action similar to the cold shock chaperones.     

Recombinant production of <Emphasis Type="Italic">Streptococcus equisimilis</Emphasis> streptokinase by <Emphasis Type="Italic">Streptomyces lividans</Emphasis>

Background  

Streptokinase (SK) is a potent plasminogen activator with widespread clinical use as a thrombolytic agent. It is naturally secreted by several strains of beta-haemolytic streptococci. The low yields obtained in SK production, lack of developed gene transfer methodology and the pathogenesis of its natural host have been the principal reasons to search for a recombinant source for this important therapeutic protein. We report here the expression and secretion of SK by the Gram-positive bacterium Streptomyces lividans. The structural gene encoding SK was fused to the Streptomyces venezuelae CBS762.70 subtilisin inhibitor (vsi) signal sequence or to the Streptomyces lividans xylanase C (xlnC) signal sequence. The native Vsi protein is translocated via the Sec pathway while the native XlnC protein uses the twin-arginine translocation (Tat) pathway.     

Evolution of <Emphasis Type="Italic">mal</Emphasis> ABC transporter operons in the <Emphasis Type="Italic">Thermococcales</Emphasis> and <Emphasis Type="Italic">Thermotogales</Emphasis>

Background  

The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry.