A GH81-type β-glucan-binding protein enhances colonization by mutualistic fungi in barley

Cell walls are important interfaces of plant-fungal interactions, acting as robust physical and chemical barriers against invaders. Upon fungal colonization, plants deposit phenolics and callose at the sites of fungal penetration to prevent further fungal progression. Alterations in the composition of plant cell walls significantly impact host susceptibility. Furthermore, plants and fungi secrete glycan hydrolases acting on each other's cell walls. These enzymes release various sugar oligomers into the apoplast, some of which activate host immunity via surface receptors. Recent characterization of cell walls from plant-colonizing fungi has emphasized the abundance of β-glucans in different cell wall layers, which makes them suitable targets for recognition. To characterize host components involved in immunity against fungi, we performed a protein pull-down with the biotinylated β-glucan laminarin. Thereby, we identified a plant glycoside hydrolase family 81-type glucan-binding protein (GBP) as a β-glucan interactor. Mutation of GBP1 and its only paralog, GBP2, in barley led to decreased colonization by the beneficial root endophytes Serendipita indica and S. vermifera, as well as the arbuscular mycorrhizal fungus Rhizophagus irregularis. The reduction of colonization was accompanied by enhanced responses at the host cell wall, including an extension of callose-containing cell wall appositions. Moreover, GBP mutation in barley also reduced fungal biomass in roots by the hemibiotrophic pathogen Bipolaris sorokiniana and inhibited the penetration success of the obligate biotrophic leaf pathogen Blumeria hordei. These results indicate that GBP1 is involved in the establishment of symbiotic associations with beneficial fungi-a role that has potentially been appropriated by barley-adapted pathogens.

Prevalence and etiology of urinary stones in hospitalized patients in Baghdad

Epidemiology and pathogenesis in urinary stones diagnosed in 184 patients were studied. Mean age was 38.3 years. Male to female ratio was 2.5:1. Stones were predominantly of mixed type: calcium oxalate was the commonest compound. Anatomical distribution of urinary stones was 67.4% renal, 12.5% ureteric and 14.6% bladder. Recurrence rate following previous surgical removal was 15.0%. Bacteria were isolated from 19 (24.4%) of 78 urinary stones: 14 were urea splitting and 5 non-urea splitting. Females had a greater chance of having infected stones. All bacteria isolated were sensitive to gentamicin and nalidixic acid. All isolates were resistant to amoxicillin and erythromycin. Multiple resistance to 6 antimicrobial agents was common (58.8%).