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1.  The DivJ, CbrA and PleC system controls DivK phosphorylation and symbiosis in Sinorhizobium meliloti 
Molecular microbiology  2013;90(1):54-71.
SUMMARY
Sinorhizobium meliloti is a soil bacterium that invades the root nodules it induces on Medicago sativa, whereupon it undergoes an alteration of its cell cycle and differentiates into nitrogen-fixing, elongated and polyploid bacteroid with higher membrane permeability. In Caulobacter crescentus, a related alphaproteobacterium, the principal cell cycle regulator, CtrA, is inhibited by the phosphorylated response regulator DivK. The phosphorylation of DivK depends on the histidine kinase DivJ, while PleC is the principal phosphatase for DivK. Despite the importance of the DivJ in C. crescentus, the mechanistic role of this kinase has never been elucidated in other Alphaproteobacteria.
We show here that the histidine kinases DivJ together with CbrA and PleC participate in a complex phosphorylation system of the essential response regulator DivK in S. meliloti. In particular, DivJ and CbrA are involved in DivK phosphorylation and in turn CtrA inactivation, thereby controlling correct cell cycle progression and the integrity of the cell envelope. In contrast, the essential PleC presumably acts as a phosphatase of DivK. Interestingly, we found that a DivJ mutant is able to elicit nodules and enter plant cells, but fails to establish an effective symbiosis suggesting that proper envelope and/or low CtrA levels are required for symbiosis.
doi:10.1111/mmi.12347
PMCID: PMC3793127  PMID: 23909720
2.  DNA Binding of the Cell Cycle Transcriptional Regulator GcrA Depends on N6-Adenosine Methylation in Caulobacter crescentus and Other Alphaproteobacteria 
PLoS Genetics  2013;9(5):e1003541.
Several regulators are involved in the control of cell cycle progression in the bacterial model system Caulobacter crescentus, which divides asymmetrically into a vegetative G1-phase (swarmer) cell and a replicative S-phase (stalked) cell. Here we report a novel functional interaction between the enigmatic cell cycle regulator GcrA and the N6-adenosine methyltransferase CcrM, both highly conserved proteins among Alphaproteobacteria, that are activated early and at the end of S-phase, respectively. As no direct biochemical and regulatory relationship between GcrA and CcrM were known, we used a combination of ChIP (chromatin-immunoprecipitation), biochemical and biophysical experimentation, and genetics to show that GcrA is a dimeric DNA–binding protein that preferentially targets promoters harbouring CcrM methylation sites. After tracing CcrM-dependent N6-methyl-adenosine promoter marks at a genome-wide scale, we show that these marks recruit GcrA in vitro and in vivo. Moreover, we found that, in the presence of a methylated target, GcrA recruits the RNA polymerase to the promoter, consistent with its role in transcriptional activation. Since methylation-dependent DNA binding is also observed with GcrA orthologs from other Alphaproteobacteria, we conclude that GcrA is the founding member of a new and conserved class of transcriptional regulators that function as molecular effectors of a methylation-dependent (non-heritable) epigenetic switch that regulates gene expression during the cell cycle.
Author Summary
Methylation of genomic DNA at a specific regulatory site can impact a myriad of processes in eukaryotic cells. In bacteria, methylation at the N6 position of adenosine (m6A) is known to mediate a non-adaptive immunity response to protect cells from foreign DNA. While m6A marks are not known to govern expression of cell cycle genes in Gammaproteobacteria, cell cycle transcription in the model alphaproteobacterium Caulobacter crescentus requires the m6A methyltransferase CcrM that introduces m6A marks at GAnTC sequences and the enigmatic factor GcrA. Investigating if a functional and biochemical relationship exists between CcrM and GcrA, we found that CcrM-dependent m6A marks recruit GcrA to the promoters of cell cycle genes in vitro and in vivo and is required for efficient transcription. GcrA interacts with RNA polymerase, explaining how cell cycle transcription is affected. Importantly, m6A-dependent binding is also seen in GcrA orthologs, indicating that this transcriptional regulatory mechanism by CcrM and GcrA is conserved in Alphaproteobacteria.
doi:10.1371/journal.pgen.1003541
PMCID: PMC3667746  PMID: 23737758
3.  Effects of regenerative radioelectric asymmetric conveyer treatment on human normal and osteoarthritic chondrocytes exposed to IL-1β. A biochemical and morphological study 
Purpose
Osteoarthritis (OA) is a degenerative disease characterized by a progressive loss of articular cartilage extracellular matrix and is due to functional impairments occurring in chondrocytes. In previous works, we highlighted that Regenerative Tissue Optimization (TO-RGN) treatment with radioelectric asymmetric conveyer (REAC) technology influenced the gene expression profiles controlling stem cell differentiation and the pluripotency of human skin-derived fibroblasts in vitro. Since interleukin-1 beta signaling has been implicated in the induction and progression of this disease (through metalloproteinase-3 synthesis and nitric oxide production), we investigated whether REAC TO-RGN might influence the biochemical and morphological changes induced by interleukin-1 beta in normal and OA chondrocytes.
Methods
The induction of metalloproteinase-3 and proteoglycan synthesis was evaluated by a solid-phase enzyme-amplified sensitivity immunoassay, and nitric oxide production was evaluated with the Griess method. Ultrastructural features were observed by transmission electron microscopy.
Results
REAC TO-RGN treatment decreased nitric oxide and metalloproteinase-3 production in normal and OA chondrocytes, while inducing an increase in proteoglycan synthesis. OA chondrocytes were more affected by REAC TO-RGN treatment than were normal chondrocytes. Ultrastructural changes confirmed that REAC TO-RGN may counteract the negative effects of interleukin-1 beta incubation.
Conclusion
The results of this in vitro study suggest that REAC TO-RGN treatment may represent a new, promising approach for the management of OA.
doi:10.2147/CIA.S42229
PMCID: PMC3653677  PMID: 23682210
human chondrocytes ultrastructure; metalloproteinase; nitric oxide; proteoglycans; REAC TO-RGN treatment
4.  Serum Amyloid A Circulating Levels and Disease Activity in Patients with Juvenile Idiopathic Arthritis 
Yonsei Medical Journal  2012;53(5):1045-1048.
The aim of our study was to evaluate the association between circulating levels of serum amyloid A protein (SAA) and disease activity in patients with juvenile idiopathic arthritis (JIA). Our study group included 41 JIA patients (9 male, 32 female), classified according to the International League of Associations for Rheumatology (ILAR) criteria (5); 16 had polyarticular onset disease and 25 had oligoarticular onset disease. Among 25 patients with oligoarticular disease, three had extended oligoarthritis. Serum amyloid A (SAA), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were measured in both patients and 26 healthy controls. SAA levels were higher in JIA patients versus healthy controls (p<0.001). Significant positive correlations were found between SAA and the presence of active joints (rho=0.363, p<0.05), the number of active joints (rho=0.418, p<0.05), ESR (R=0.702, p<0.05) and CRP (R=0.827, p<0.05). No significant correlations between ESR and the presence of active joints (rho=0.221, p=0.225) or between ESR and the number of active joints (rho=0.118, p=0.520) were demonstrated in JIA patients. No significant correlations were obtained between CRP and the presence of active joints (rho=0.034, p=0.855) or between CRP and the number of active joints (rho=0.033, p=0.859). We discovered a significant increase in SAA levels in JIA patients, compared to controls, and a strong positive correlation between SAA level and JIA disease activity. We also discerned SAA to be a more sensitive laboratory marker than ESR and CRP for evaluating the presence and number of active joints. We suggest that SAA can be used as an additional indicator of disease activity in JIA.
doi:10.3349/ymj.2012.53.5.1045
PMCID: PMC3423833  PMID: 22869491
Serum amyloid A; juvenile idiopathic arthritis; inflammatory markers; disease activity
5.  Structural insights into ChpT, an essential dimeric histidine phosphotransferase regulating the cell cycle in Caulobacter crescentus  
The cell-cycle regulator ChpT of C. crescentus is a dimeric histidine phosphotransferase that resembles the typical structure of histidine kinases.
Two-component and phosphorelay signal-transduction proteins are crucial for bacterial cell-cycle regulation in Caulobacter crescentus. ChpT is an essential histidine phosphotransferase that controls the activity of the master cell-cycle regulator CtrA by phosphorylation. Here, the 2.2 Å resolution crystal structure of ChpT is reported. ChpT is a homodimer and adopts the domain architecture of the intracellular part of class I histidine kinases. Each subunit consists of two distinct domains: an N-terminal helical hairpin domain and a C-terminal α/β domain. The two N-terminal domains are adjacent within the dimer, forming a four-helix bundle. The ChpT C-terminal domain adopts an atypical Bergerat ATP-binding fold.
doi:10.1107/S1744309112033064
PMCID: PMC3433190  PMID: 22949187
bacterial cell cycle; Caulobacter crescentus; histidine kinases; histidine phosphotransferases
6.  Fibromyalgia Syndrome and Spa Therapy: Myth or Reality? 
Fibromyalgia syndrome (FS) is a common musculoskeletal disorder characterized by otherwise unexplained chronic widespread pain, a lowered pain threshold, high tender point counts, sleep disturbances, fatigue, headache, irritable bowel syndrome, morning stiffness, paraesthesias in the extremities, often psychological distress and depressed mood. Consequently, FS has a negative impact on working capacity, family life, social functioning and quality of life. Because of unknown etiology and not clearly understood pathogenesis, there is no standard therapy regime for FS. A variety of medical treatments, including antidepressants, opioids, analgesic or non-steroidal anti-inflammatory drugs, sedatives, muscle relaxants and antiepileptics, have been used to treat FS. Currently, no pharmacological treatment for FS is consistently successful. According to recent guidelines, the optimal treatment of FS requires a multidisciplinary approach with a combination of non-pharmacological and pharmacological treatment modalities. Spa therapy is a popular treatment for FS in many European countries, as well as in Japan and Israel. However, despite their long history and popularity spa treatments are still the subject of debate and their role in modern medicine is still not clear. The objective of this review is to summarize the currently available information on clinical effects and mechanism of action of spa therapy in FS. We also provide some suggestions for further development in this area.
doi:10.4137/CMAMD.S8797
PMCID: PMC3296493  PMID: 22408369
spa therapy; fibromyalgia syndrome; balneotherapy; mud-packs; randomized clinical trial
7.  Exploring the symbiotic pangenome of the nitrogen-fixing bacterium Sinorhizobium meliloti 
BMC Genomics  2011;12:235.
Background
Sinorhizobium meliloti is a model system for the studies of symbiotic nitrogen fixation. An extensive polymorphism at the genetic and phenotypic level is present in natural populations of this species, especially in relation with symbiotic promotion of plant growth. AK83 and BL225C are two nodule-isolated strains with diverse symbiotic phenotypes; BL225C is more efficient in promoting growth of the Medicago sativa plants than strain AK83. In order to investigate the genetic determinants of the phenotypic diversification of S. meliloti strains AK83 and BL225C, we sequenced the complete genomes for these two strains.
Results
With sizes of 7.14 Mbp and 6.97 Mbp, respectively, the genomes of AK83 and BL225C are larger than the laboratory strain Rm1021. The core genome of Rm1021, AK83, BL225C strains included 5124 orthologous groups, while the accessory genome was composed by 2700 orthologous groups. While Rm1021 and BL225C have only three replicons (Chromosome, pSymA and pSymB), AK83 has also two plasmids, 260 and 70 Kbp long. We found 65 interesting orthologous groups of genes that were present only in the accessory genome, consequently responsible for phenotypic diversity and putatively involved in plant-bacterium interaction. Notably, the symbiosis inefficient AK83 lacked several genes required for microaerophilic growth inside nodules, while several genes for accessory functions related to competition, plant invasion and bacteroid tropism were identified only in AK83 and BL225C strains. Presence and extent of polymorphism in regulons of transcription factors involved in symbiotic interaction were also analyzed. Our results indicate that regulons are flexible, with a large number of accessory genes, suggesting that regulons polymorphism could also be a key determinant in the variability of symbiotic performances among the analyzed strains.
Conclusions
In conclusions, the extended comparative genomics approach revealed a variable subset of genes and regulons that may contribute to the symbiotic diversity.
doi:10.1186/1471-2164-12-235
PMCID: PMC3164228  PMID: 21569405
Sinorhizobium meliloti; nodulation; symbiosis; comparative genomics; pangenome; panregulon
8.  The efficacy and tolerability of glucosamine sulfate in the treatment of knee osteoarthritis: A randomized, double-blind, placebo-controlled trial 
Background: Osteoarthritis (OA) is the most common form of arthritis and is often associated with disability and impaired quality of life.
Objective: The aim of the study was to assess the efficacy and tolerability of glucosamine sulfate (GS) in the treatment of knee OA.
Methods: Consecutive outpatients affected by primary monolateral or bilateral knee OA were enrolled in this double-blind, double-dummy, prospective, randomized, placebo-controlled trial. One group received GS 1500 mg QD for 12 weeks, and the other group received placebo QD for 12 weeks. The treatment period was followed by a 12-week treatment-free observation phase. Each patient was examined at baseline and at weeks 4, 8, 12, 16, 20, and 24. The primary efficacy criteria were pain at rest and during movement, assessed on a visual analog scale (VAS) of 0 to 100 mm. The secondary criteria included the Western Ontario and McMaster Universities (WOMAC) index for total pain score (W-TPS), total stiffness score (W-TSS), and total physical function score (W-TPFS). VAS, W-TPS, W-TSS, and W-TPFS were evaluated at baseline and at weeks 4, 8, 12, 16, 20, and 24. Analgesic drug consumption (ie, acetaminophen or NSAIDs) was also assessed.
Results: Patient demographics were similar in the GS and placebo groups. Of 60 randomized patients (30 per group), 56 completed the study (28 treated with GS and 28 who received placebo). Statistically significant improvements in symptomatic knee OA were observed, as measured by differences in resting pain at weeks 8, 12, and 16 (all, P < 0.05 vs placebo) and in pain during movement at weeks 12 and 16 (both, P < 0.05). W-TPS was lower with GS than placebo at weeks 8, 12, and 16 (all, P < 0.01), and at week 20 (P < 0.05). W-TSS was also lower with GS than placebo at weeks 8, 12, 16, and 20 (all, P < 0.05). W-TPFS was lower with GS than placebo at weeks 8 (P < 0.05), 12 (P < 0.01), 16 (P < 0.05), and 20 (P < 0.05). Drug consumption was lower in the GS group than the placebo group at weeks 8, 12, 16, and 20 (all, P < 0.05). The incidence of adverse events was 36.7% with GS and 40.0% with placebo.
Conclusions: GS 1500 mg QD PO for 12 weeks was associated with statistically significant reductions in pain and improvements in functioning, with decreased analgesic consumption, compared with baseline and placebo in these patients with knee OA. A carryover effect was detected after treatment ended.
doi:10.1016/j.curtheres.2009.05.004
PMCID: PMC3967292  PMID: 24683229
glucosamine sulfate; knee osteoarthritis; efficacy; carryover effect; tolerability

Results 1-8 (8)