Unique features of the rice blast resistance <Emphasis Type="Italic">Pish</Emphasis> locus revealed by large scale retrotransposon-tagging

Background  

R gene-mediated resistance is one of the most effective mechanisms of immunity against pathogens in plants. To date some components that regulate the primary steps of plant immunity have been isolated, however, the molecular dissection of defense signaling downstream of the R proteins remains to be completed. In addition, R genes are known to be highly variable, however, the molecular mechanisms responsible for this variability remain obscure.     

TaRPP13-3, a CC-NBS-LRR-like gene located on chr 7D,promotes disease resistance to wheat powdery mildew in Brock

Disease resistance (R) gene, RPP13, plays an important role in the resistance of plants to pathogen infections; its function in resistance of wheat to powdery mildew remains unknown. In this study, a RNA-Seq technique was used to monitor expression of genes in susceptible wheat ‘Jing411’ and resistant near-isogenic line ‘BJ-1’ in response to powdery mildew infection. Overall, 413 differential expression genes were observed and identified as involved in disease resistance. RPP13 homologous gene on wheat chromosome 7D was preliminarily identified using the wheat 660K SNP chip. RPP13 was highly expressed in ‘BJ-1’ and encodes 1,027 amino acids, including CC, NB and LRR domain, termed TaRPP13-3. After inoculation with powdery mildew, expression of TaRPP13-3 in resistant wheat changed with time, but average expression was higher when compared to susceptible variety, thus indicating that TaRPP13-3 is involved in resistance to powdery mildew. Virus-induced gene silencing (VIGS) was used to inhibit expression of TaRPP13-3 in resistant parent ‘Brock’. Results indicated that silencing of TaRPP13-3 led to decreased disease resistance in ‘Brock’. Overall results of this study indicate that TaRPP13-3 gene is involved in the defence response of wheat to powdery mildew and plays a positive role in wheat powdery mildew interactions.     

Filamin repeat segments required for photosensory signalling in <Emphasis Type="Italic">Dictyostelium discoideum</Emphasis>

Background  

Filamin is an actin binding protein which is ubiquitous in eukaryotes and its basic structure is well conserved – an N-terminal actin binding domain followed by a series of repeated segments which vary in number in different organisms. D. discoideum is a well established model organism for the study of signalling pathways and the actin cytoskeleton and as such makes an excellent organism in which to study filamin. Ddfilamin plays a putative role as a scaffolding protein in a photosensory signalling pathway and this role is thought to be mediated by the unusual repeat segments in the rod domain.     

Successfully resisting a pathogen is rarely costly in <Emphasis Type="Italic">Daphnia magna</Emphasis>

Background  

A central hypothesis in the evolutionary ecology of parasitism is that trade-offs exist between resistance to parasites and other fitness components such as fecundity, growth, survival, and predator avoidance, or resistance to other parasites. These trade-offs are called costs of resistance. These costs fall into two broad categories: constitutive costs of resistance, which arise from a negative genetic covariance between immunity and other fitness-related traits, and inducible costs of resistance, which are the physiological costs incurred by hosts when mounting an immune response. We sought to study inducible costs in depth using the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa.     

Disease resistance gene homologs correlate with disease resistance loci of Arabidopsis thaliana

The disease resistance genes RPS2 of Arabidopsis and N of tobacco, among other recently cloned resistance genes, share several conserved sequences. Degenerate oligonucleotide primers, based on conserved sequences in the nucleotide binding site (NBS) and a weak hydrophobic domain of RPS2 and N, were used to amplify homologous sequences from Arabidopsis thaliana. Amplification products were obtained that were similar in sequence to the disease resistance genes RPS2, RPM1, N and L6. The Arabidopsis CIC-YAC library was used to identify the position of the disease resistance homologs on the Arabidopsis genome. Their map positions could be correlated with the disease resistance loci RPS5, RAC1, RPP9, CAR1, RPP7, RPW2, RPP1, RPP10, RPP14, RPP5, RPP4, RPS2, RPW6, HRT, RPS4, RPP8, RPP21, RPP22, RPP23, RPP24 and TTR1. This method was therefore not only successful in the identification of sequences located within gene clusters that are involved in disease resistance, but could also contribute to the cloning of disease resistance genes from Arabidopsis.     

<Emphasis Type="Italic">Candida albicans SUR7</Emphasis> contributes to secretion,biofilm formation,and macrophage killing

Background  

Candida albicans SUR7 has been shown to be required for plasma membrane organization and cell wall synthesis, but its role in virulence is not known. Using a bioinformatics strategy, we previously identified several novel putative secretion pathway proteins potentially involved in virulence, including the C. albicans homolog of the Saccharomyces cerevisiae endocytosis-related protein Sur7p. We therefore generated a C. albicans sur7Δ null mutant and examined its contribution to key virulence attributes.     

Bio-informatics analysis of a gene co-expression module in adipose tissue containing the diet-responsive gene <Emphasis Type="Italic">Nnat</Emphasis>

Background  

Obesity causes insulin resistance in target tissues - skeletal muscle, adipose tissue, liver and the brain. Insulin resistance predisposes to type-2 diabetes (T2D) and cardiovascular disease (CVD). Adipose tissue inflammation is an essential characteristic of obesity and insulin resistance. Neuronatin (Nnat) expression has been found to be altered in a number of conditions related to inflammatory or metabolic disturbance, but its physiological roles and regulatory mechanisms in adipose tissue, brain, pancreatic islets and other tissues are not understood.     

Costs and benefits of multiple resistance to insecticides for <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> mosquitoes

Background  

The evolutionary dynamics of xenobiotic resistance depends on how resistance mutations influence the fitness of their bearers, both in the presence and absence of xenobiotic selection pressure. In cases of multiple resistance, these dynamics will also depend on how individual resistance mutations interact with one another, and on the xenobiotics applied against them. We compared Culex quinquefasciatus mosquitoes harbouring two resistance alleles ace-1 ^R and Kdr ^R (conferring resistance to carbamate and pyrethroid insecticides, respectively) to mosquitoes bearing only one of the alleles, or neither allele. Comparisons were made in environments where both, only one, or neither type of insecticide was present.     

<Emphasis Type="Italic">Brucella abortus ure2</Emphasis> region contains an acid-activated urea transporter and a nickel transport system

Background  

Urease is a virulence factor that plays a role in the resistance of Brucella to low pH conditions, both in vivo and in vitro. Brucella contains two separate urease gene clusters, ure1 and ure2. Although only ure1 codes for an active urease, ure2 is also transcribed, but its contribution to Brucella biology is unknown.     

Identification of critical residues in Gap3 of <Emphasis Type="Italic">Streptococcus parasanguinis</Emphasis> involved in Fap1 glycosylation,fimbrial formation and <Emphasis Type="Italic">in vitro</Emphasis>adhesion

Background  

Streptococcus parasanguinis is a primary colonizer of human tooth surfaces and plays an important role in dental plaque formation. Bacterial adhesion and biofilm formation are mediated by long peritrichous fimbriae that are composed of a 200 kDa serine rich glycoprotein named Fap1 (fimbriae-associated protein). Glycosylation and biogenesis of Fap1 are modulated by a gene cluster downstream of the fap1 locus. A gene encoding a glycosylation-associated protein, Gap3, was found to be important for Fap1 glycosylation, long fimbrial formation and Fap1-mediated biofilm formation.     

<Emphasis Type="Italic">Constitutive Expressor of Pathogenesis-Related Genes5</Emphasis>affects cell wall biogenesis and trichome development

Background  

The Arabidopsis thaliana CONSTITUTIVE EXPRESSOR OF PATHOGENESIS-RELATED GENES5 (CPR5) gene has been previously implicated in disease resistance, cell proliferation, cell death, and sugar sensing, and encodes a putative membrane protein of unknown biochemical function. Trichome development is also affected in cpr5 plants, which have leaf trichomes that are reduced in size and branch number.     

Analysis of the ArcA regulon in anaerobically grown <Emphasis Type="Italic">Salmonella enterica sv</Emphasis>. Typhimurium

Background  

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a Gram-negative pathogen that must successfully adapt to the broad fluctuations in the concentration of dissolved dioxygen encountered in the host. In Escherichia coli, ArcA (Aerobic Respiratory Control) helps the cells to sense and respond to the presence of dioxygen. The global role of ArcA in E. coli is well characterized; however, little is known about its role in anaerobically grown S. Typhimurium.     

Aciculatin inhibits lipopolysaccharide-mediated inducible nitric oxide synthase and cyclooxygenase-2 expression via suppressing NF-κB and JNK/p38 MAPK activation pathways

Objectives  

Natural products have played a significant role in drug discovery and development. Inflammatory mediators such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been suggested to connect with various inflammatory diseases. In this study, we explored the anti-inflammatory potential of aciculatin (8-((2R,4S,5S,6R)-tetrahydro-4,5-dihydroxy-6-methyl-2H-pyran-2-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one), one of main components of Chrysopogon aciculatis, by examining its effects on the expression and activity of iNOS and COX-2 in lipopolysaccharide (LPS)-activated macrophages.     

The clathrin-binding motif and the J-domain of <Emphasis Type="Italic">Drosophila Auxilin</Emphasis> are essential for facilitating Notch ligand endocytosis

Background  

Ligand endocytosis plays a critical role in regulating the activity of the Notch pathway. The Drosophila homolog of auxilin (dAux), a J-domain-containing protein best known for its role in the disassembly of clathrin coats from clathrin-coated vesicles, has recently been implicated in Notch signaling, although its exact mechanism remains poorly understood.