Qri7/OSGEPL,the mitochondrial version of the universal Kae1/YgjD protein,is essential for mitochondrial genome maintenance

Yeast Qri7 and human OSGEPL are members of the orthologous Kae1(OSGEP)/YgjD protein family, the last class of universally conserved proteins without assigned function. Phylogenetic analyses indicate that the eukaryotic Qri7(OSGEPL) proteins originated from bacterial YgjD proteins. We have recently shown that the archaeal Kae1 protein is a DNA-binding protein that exhibits apurinic endonuclease activity in vitro. We show here that the Qri7/OSGEPL proteins localize in mitochondria and are involved in mitochondrial genome maintenance in two model eukaryotic organisms, Saccharomyces cerevisiae and Caenorhabditis elegans. Furthermore, S. cerevisiae Qri7 complements the loss of the bacterial YgjD protein in Escherichia coli, suggesting that Qri7/OSGEPL and YgjD proteins have retained similar functions in modern organisms. We suggest to name members of the Kae1(OSGEP)/YgjD family UGMP, for Universal Genome Maintenance Proteins.     

Response of Rhizobial Populations to Moderate Copper Stress Applied to an Agricultural Soil

The use of pesticides in agricultural soils may affect the soil microbiota. The effect of repeated application of copper sulfate in soil on indigenous populations of rhizobia was assessed in a medium-term field experiment. Copper sulfate was applied over 8 years at two different rates, 12.5 and 50 kg of CuSO₄ ha^–1 year^–1, in the field. The concentrations of total copper in soil varied between 14.0 (control plots that did not receive copper sulfate) and 91.0 mg kg^–1 (the most contaminated plots) at the time of sampling, 3 years after the end of the copper treatments. All the other physicochemical parameters were similar among the plots that also shared the same cropping history. The target rhizobia were monospecific populations of Rhizobium leguminosarum bv. viciae nodulating Vicia sativa and communities of rhizobial species nodulating Phaseolus vulgaris. The size of the vetch rhizobial populations was significantly reduced in the soils with the higher Cu content, whereas the size of the Phaseolus rhizobial populations was not significantly affected. However, the number of nodules formed on both vetches and common beans were reduced for the plants grown in the most contaminated soils, suggesting an additional toxic effect of copper on plant physiology. The diversity (Simpson's indices) of rhizobial genotypes, as characterized by polymerase chain reaction restriction fragment length polymorphism of 16S–23S rDNA intergenic spacer (IGS), was not influenced by copper application. Also, the genetic structure of the R. leguminosarum bv. viciae populations was not modified by copper treatments. By contrast, a shift was observed in the composition of the Phaseolus-nodulating communities in relation to soil copper content. The communities were composed of three 16S rDNA haplotypes: one corresponding to the R. leguminosarum (biovar phaseoli) species, the two others forming a new lineage of Phaseolus rhizobia based on 16S rDNA sequence analysis. The reduced frequency of the R. leguminosarum species in the Phaseolus-nodulating communities from the copper-treated soils was linked to its higher sensitivity to copper as compared to the higher tolerance of isolates belonging to the other rhizobial lineage. The new lineage was functionally efficient for symbiotic nitrogen fixation with P. vulgaris. Our results suggest that functional redundancy among species exhibiting variability for copper tolerance preserved the size of Phaseolus-nodulating communities. In contrast, the abundance of the vetch-nodulating rhizobia, which was a monospecific functional group mainly constituted by copper-sensitive genotypes, was adversely affected by repeated application of copper sulfate.     

Transition of healthy to diseased synovial tissue in rheumatoid arthritis is associated with gain of mesenchymal/fibrotic characteristics

The healthy synovial lining layer consists of a single cell layer that regulates the transport between the joint cavity and the surrounding tissue. It has been suggested that abnormalities such as somatic mutations in the p53 tumor-suppressor gene contribute to synovial hyperplasia and invasion in rheumatoid arthritis (RA). In this study, expression of epithelial markers on healthy and diseased synovial lining tissue was examined. In addition, we investigated whether a regulated process, resembling epithelial to mesenchymal transition (EMT)/fibrosis, could be responsible for the altered phenotype of the synovial lining layer in RA. Synovial tissue from healthy subjects and RA patients was obtained during arthroscopy. To detect signs of EMT, expression of E-cadherin (epithelial marker), collagen type IV (indicator of the presence of a basement membrane) and alpha-smooth muscle actin (alpha-sma; a myofibroblast marker) was investigated on frozen tissue sections using immunohistochemistry. Fibroblast-like synoviocytes (FLSs) from healthy subjects were isolated and subjected to stimulation with synovial fluid (SF) from two RA patients and to transforming growth factor (TGF)-beta. To detect whether EMT/fibrotic markers were increased, expression of collagen type I, alpha-sma and telopeptide lysylhydroxylase (TLH) was measured by real time PCR. Expression of E-cadherin and collagen type IV was found in healthy and arthritic synovial tissue. Expression of alpha-sma was only found in the synovial lining layer of RA patients. Stimulation of healthy FLSs with SF resulted in an upregulation of alpha-sma and TLH mRNA. Collagen type I and TLH mRNA were upregulated after stimulation with TGF-beta. Addition of bone morphogenetic protein (BMP)-7 to healthy FLS stimulated with SF inhibited the expression of alpha-sma mRNA. The finding that E-cadherin and collagen type IV are expressed in the lining layer of healthy and arthritic synovium indicates that these lining cells display an epithelial-like phenotype. In addition, the presence of alpha-sma in the synovial lining layer of RA patients and induction of fibrotic markers in healthy FLSs by SF from RA patients indicate that a regulated process comparable to EMT might cause the alteration in phenotype of RA FLSs. Therefore, BMP-7 may represent a promising agent to counteract the transition imposed on synoviocytes in the RA joint.     

Rheumatoid synovial fluid interleukin-17-producing CD4 T cells have abundant tumor necrosis factor-alpha co-expression,but little interleukin-22 and interleukin-23R expression

Introduction  

Th17 cells have been implicated in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to systematically analyse the phenotype, cytokine profile and frequency of interleukin-17 (IL-17) producing CD4-positive T cells in mononuclear cells isolated from peripheral blood, synovial fluid and synovial tissue of RA patients with established disease, and to correlate cell frequencies with disease activity.     

Effect of Tetracosactid on Post Partum Cyclicity in Cows after Induction of Parturition with PGF2α

Parturition and retention of fetal membranes were induced with PGF_2α in 3 primiparous dairy cows. Starting on day 12 post partum (PP) the cows were treated with 500 μ g i.m. of ACTH-analogue (tetracosactid) every 6 h for 6 times. Changes in plasma concentrations of cortisol, progesterone and 15-ketodihydro-PGF_2α were evaluated immediately after treatment. The effects on the resumption of ovarian activity were evaluated by clinical and ultrasound examinations and by progesterone and 15-ketodihydro-PGF_2α analyses for 56 days after parturition. Treatment was able to induce a statistically significant (p < 0.01) similar increase in cortisol and progesterone after both the 1^st and the 6^th injections, in all cows. No changes in 15-ketodihydro-PGF_2αconcentrations were seen after any of the injections of ACTH-analogue. The first corpus luteum (CL) was seen on day 18 PP (cow A), and 28 (cow B) and in both cases it was followed by a normal ovarian cyclicity. No CL was observed during the whole period of study in cow C. Progesterone profiles confirmed these clinical and ultrasonographic findings. The steroid output, especially progesterone, induced by the ACTH-analogue might be a stimulus for the onset of ovarian cyclicity, since 2 of the 3 animals ovulated earlier than expected. These findings point to the fact that interference with the stress system might have a positive effect on ovarian cyclicity. The different pattern of response does however demand further studies.     

Surface colonization of lodgepole pine (Pinus contorta var. latifolia [Dougl. Engelm.]) roots by Pseudomonas fluorescens and Paenibacillus polymyxa under gnotobiotic conditions

Indirect immunofluorescence techniques and confocal scanning laser microscopy were used to identify rhizobacterial strains on the root surfaces of pine seedlings, which were grown from seeds under gnotobiotic conditions. Conifer plant growth promoting rhizobacterial strains Paenibacillus polymyxa L6 and Pw-2, and the forest soil isolate Pseudomonas fluorescens M20, were inoculated onto surface-disinfested pine seeds, singly, or in dual combinations: strains L6 + M20, or strains Pw-2 + M20. Segments containing particular root microsites (root tip, root hair zone, or areas of lateral root emergence) were sampled randomly from roots 7 or 13 weeks after inoculation, and the colonization of roots by each bacterium was observed. Root segments were also sampled from individual roots at six different points along the length of the root, and the qualitative colonization of younger areas, closer to the root tip, contrasted with that of older areas, closer to the root base. The ability of strain M20 to colonize root areas adjacent to sites of lateral root emergence improves in the presence of either P. polymyxa strain, while the ability of the P. polymyxa strains to colonize these areas was not affected. More rhizobacteria were also generally observed on younger root tissues than on areas closer to the root base.     

Disruption of the subtilase gene, albin1, in Ophiostoma piliferum

Wood sapstaining fungi produce multiple proteases that break down wood protein. Three groups of subtilases have been identified in sapstaining fungi; however, it is not known if these groups have distinct physiological roles (B. Hoffman and C. Breuil, Curr. Genet. 41:168-175, 2002). In this work we examined the role of the subtilase Albin1 from Ophiostoma piliferum. Reamplification of cDNA ends PCR was used to obtain the albin1 gene sequence. The encoded subtilase is probably extracellular and involved in nutrient acquisition. This gene was disrupted with an Agrobacterium tumefaciens-mediated transformation system. Two of the disruptants obtained had significantly lower levels of proteolytic activity, slower growth in bovine serum albumin, and significantly reduced growth on wood. Thus, albin1 plays an important role in O. piliferum's ability to acquire nitrogen from wood proteins.     

Distinguishing Ophiostoma ips and Ophiostoma montium,two bark beetle-associated sapstain fungi

Two synonymous sapstain species, Ophiostoma montium and Ophiostoma ips, which are vectored by Dendroctonus ponderosae and various bark beetles, respectively, were differentiated into separate species using growth and molecular characteristics. Analysis of 32 isolates of the two species from different countries showed that O. ips was able to grow at 35 degrees C while O. montium was not. This growth-based differentiation was strongly supported by sequence data for the internal transcribed spacer (ITS), 5.8S and partial 28S rDNA, and the beta-tubulin genes. The beta-tubulin gene sequence data indicate that the two species can easily be differentiated with a single polymerase chain reaction (PCR) assay.