Cytoskeletal responses during early development of the downy mildew of grapevine (Plasmopara viticola)

A host-free system was established to induce the early development of the obligate biotrophic pathogen Plasmopara viticola, the downy mildew of grapevine. This system was used to study cytoskeletal responses during encystation and germ tube formation. During these processes, both the actin and the tubulin cytoskeleton show a stage-specific pattern of distribution. Elimination of the cytoskeleton by the actin drug latrunculin B and the microtubule drug ethyl-N-phenyl-carbamate did not affect the release of mobile zoospores from the sporangia, nor the encystation process, but efficiently inhibited the formation of a germ tube. The data are discussed with respect to a role of both actin and microtubules for the establishment of the cell polarity guiding the emergence and the growth of the germ tube.     

Monocytes/macrophages express chemokine receptor CCR9 in rheumatoid arthritis and CCL25 stimulates their differentiation

Introduction  

Monocytes/macrophages accumulate in the rheumatoid (RA) synovium where they play a central role in inflammation and joint destruction. Identification of molecules involved in their accumulation and differentiation is important to inform therapeutic strategies. This study investigated the expression and function of chemokine receptor CCR9 in the peripheral blood (PB) and synovium of RA, non-RA patients and healthy volunteers.     

Lipidic phase membrane protein serial femtosecond crystallography

X-ray free electron laser (X-FEL)-based serial femtosecond crystallography is an emerging method with potential to rapidly advance the challenging field of membrane protein structural biology. Here we recorded interpretable diffraction data from micrometer-sized lipidic sponge phase crystals of the Blastochloris viridis photosynthetic reaction center delivered into an X-FEL beam using a sponge phase micro-jet.     

Association of genetic variants rs641153 (CFB), rs2230199 (C3), and rs1410996 (CFH) with age-related macular degeneration in a Brazilian population

This study aimed to investigate the association among genetic variants of the complement pathway CFB R32Q (rs641153), C3 R102G (rs2230199), and CFH (rs1410996) with age-related macular degeneration (AMD) in a sample of the Brazilian population. In a case-control study, 484 AMD patients were classified according to the clinical age-related maculopathy grading system (CARMS) and compared to 479 unrelated controls. The genetic variants rs1410996 of complement H (CFH), rs641153 of complement factor B (CFB), and rs2230199 of complement 3 (C3) were evaluated through polymerase chain reaction (PCR) and direct sequencing. The associations between single nucleotide polymorphisms (SNPs) and AMD, adjusted by age, were assessed by using logistic regression models. A statistically significant association was observed between AMD risk and rs2230199 variant with an OR of 2.01 (P  = 0.0002) for CG individuals compared to CC individuals. Regarding the comparison of advanced AMD versus the control group, the OR was 2.12 (P = 0.0036) for GG versus AA genotypes for rs1410996 variant. Similarly, the OR for rs2230199 polymorphism was 2.3034 (P  = 5.47^e-05) when comparing CG individuals to CC carriers. In contrast, the rs641153 variant showed a significant protective effect against advanced AMD for GA versus GG genotype (OR = 0.4406; P  = 0.0019). When comparing wet AMD versus controls, a significant association was detected for rs1410996 variant (OR = 2.16; P  = 0.0039) comparing carriers of the homozygous GG versus AA genotype, as well as in the comparisons of GG (OR = 3.0713; P  = 0.0046) and CG genotypes (OR = 2.2249; P  = 0.0002) versus CC genotype for rs2230199 variant, respectively. The rs641153 variant granted a significant protective effect against wet AMD for GA versus GG genotypes (OR = 0.4601; P  = 0.0044). Our study confirmed the risk association between rs2230199 and rs1410996 variants and AMD, and the protective role against AMD for rs641153 variant.     

Molecular phylogeny of the genus Vitis (Vitaceae) based on plastid markers

? Premise of the study: This work represents the first molecular phylogeny of the economically important genus Vitis, an important genetic resource for breeding in grapevine, Vitis vinifera. ? Methods: A molecular phylogeny of Vitis using a combined data set of three noncoding regions of the plastid DNA genome was constructed from 47 accessions covering 30 species of Vitis. The data for the trnL-F marker were combined with previously published data across the Vitaceae. ? Key results: The molecular phylogeny demonstrated monophyly of the genus Vitis. Based on the combined analysis of three genes, Vitis is split into three clades that mirror the continental distribution of these accessions. The diversity is highest in the Asian clade, but the general genetic distances across taxa from different continents are relatively small. ? Conclusions: The findings support a relatively recent and intense gene flow between East Asia and North America and the possible impact of hybridization on the evolution of the genus Vitis. Taxon identity in important stock collections should be screened carefully because roughly 10% of the accessions analyzed in the present study had been misidentified.     

The mode of interaction between Vitis and Plasmopara viticola Berk. & Curt. Ex de Bary depends on the host species

In order to obtain insight into host responses to grapevine downy mildew ( Plasmopara viticola ), we compared pathogen development on a panel of Vitis species from North America, Asia and Europe. Leaf discs from different host species were inoculated in parallel, and the colonisation of the mesophyll was visualised by aniline blue staining and quantified with respect to infection incidence and mycelial growth. In parallel, the morphology of guard cells was screened for the presence of an internal cuticular rim after staining with acridine orange and using low-temperature scanning electron microscopy. We observed three response patterns: (i) inhibition of pathogen development early after attachment of zoospores; (ii) successful colonisation of the mesophyll by the pathogen; and (iii) aberrant development, where the pathogen does not attach to guard cells, but produces hyphae on the leaf surface without formation of viable sporangiophores. Inhibition is observed in the North American and Siberian species, successful colonisation prevails in the European hosts, and surface hyphae are found on non-Siberian Asiatic species. We propose that the interaction between host and pathogen is under control of specific signals that have been subject to evolutionary diversification.     

Fucosebeta-1-P-Ser is a new type of glycosylation: using antibodies to identify a novel structure in Dictyostelium discoideum and study multiple types of fucosylation during growth and development

Three antibodies that recognize distinct fucose epitopes were used to study fucosylation during growth and development of Dictyostelium discoideum. mAb83.5 is known to recognize an undefined "fucose epitope" on several proteins with serine-rich domains, while mAb CAB4, and a component of anti-horse-radish peroxidase, specifically recognize Fucalpha1,6GlcNAc and Fucalpha1,3GlcNAc residues respectively in the core of N-linked oligosaccharides. We show that mAb 83.5 defines a new type of O-glycosylation. Serine-containing peptides incubated with GDPbeta[3H]Fuc and microsomes formed two fucosylated products. A neutral product accounting for 30% of the label did not react with the antibody, while the rest of the label was incorporated into a charged product which contained all the mAb83.5 reactive material. beta- Elimination of the labeled peptide or endogenous products produced [3H]Fuc-1-P, indicating phosphodiester linkage to serine. Fucbeta-1-P and GDP-betaFuc at 100 microM blocked mAb83.5 binding to endogenous and peptide products, but their alpha-linked anomers did not. Electrospray ionization mass spectra of the neutral and anionic labeled products showed major peaks of mass units corresponding to O-Fuc-Ser peptide and O-Fuc-phospho-Ser peptide, respectively. The activity of Fuc- phosphotransferase exactly paralleled the accumulation of reactive glycans during growth and development. The expressions of N-glycan core Fucalpha1,6GlcNAc and Fucalpha1,3GlcNAc and their respective fucosyl transferase activities were also synchronous, but their developmental regulation differed from one another. Fucalpha1, 6GlcNAc was expressed maximally during growth but declined during development. In contrast core Fucalpha1,3GlcNAc epitopes were expressed almost exclusively during development. These findings provide direct evidence for a novel type of O-phosphofucosylation, demonstrate the existence of an O- fucosyl transferase, and identify two different types of core fucosylation in the N-glycans of Dictyostelium.