Bacterial nitrate assimilation: gene distribution and regulation

In the context of the global nitrogen cycle, the importance of inorganic nitrate for the nutrition and growth of marine and freshwater autotrophic phytoplankton has long been recognized. In contrast, the utilization of nitrate by heterotrophic bacteria has historically received less attention because the primary role of these organisms has classically been considered to be the decomposition and mineralization of dissolved and particulate organic nitrogen. In the pre-genome sequence era, it was known that some, but not all, heterotrophic bacteria were capable of growth on nitrate as a sole nitrogen source. However, examination of currently available prokaryotic genome sequences suggests that assimilatory nitrate reductase (Nas) systems are widespread phylogenetically in bacterial and archaeal heterotrophs. Until now, regulation of nitrate assimilation has been mainly studied in cyanobacteria. In contrast, in heterotrophic bacterial strains, the study of nitrate assimilation regulation has been limited to Rhodobacter capsulatus, Klebsiella oxytoca, Azotobacter vinelandii and Bacillus subtilis. In Gram-negative bacteria, the nas genes are subjected to dual control: ammonia repression by the general nitrogen regulatory (Ntr) system and specific nitrate or nitrite induction. The Ntr system is widely distributed in bacteria, whereas the nitrate/nitrite-specific control is variable depending on the organism

Adaptive Radiation in Mediterranean Cistus (Cistaceae)

lineage consists of 12 species primarily distributed in Mediterranean habitats and is herein subject to analysis. lineages), which display asymmetric characteristics: number of species (2 vs. 10), leaf morphologies (linear vs. linear to ovate), floral characteristics (small, three-sepalled vs. small to large, three- or five-sepalled flowers) and ecological attributes (low-land vs. low-land to mountain environments). A positive phenotype-environment correlation has been detected by historical reconstructions of morphological traits (leaf shape, leaf labdanum content and leaf pubescence). Ecological evidence indicates that modifications of leaf shape and size, coupled with differences in labdanum secretion and pubescence density, appear to be related to success of new species in different Mediterranean habitats.

Endoscopically placed stents: a useful alternative for the management of refractory benign cervical esophageal stenosis

Introduction: Benign esophageal strictures are relatively frequent and can severely affect the quality of life of a patient. Stenting has been proposed for the treatment of refractory cases. Lesions affecting the cervical esophagus are more difficult to treat, and the placement of stents in this location has traditionally been restricted due to potential adverse events. The aim of this study was to describe the efficacy and safety of endoscopic stenting in the management of refractory benign cervical esophageal strictures (RBCES) in a single-center cohort study. Methods: We analyzed 12 patients with RBCES (Kochman's criteria) and severe dysphagia. We recorded previous endoscopic treatments, stricture characteristics and demographic data. The two types of stents used were fully covered self-expandable metallic stents (FCSEMS) and uncovered biodegradable stents (BDS). FCSEMS were removed eight weeks after placement, and BDS were followed-up until degradation. We assessed technical and clinical success, rate of stricture recurrence and adverse events. Results: The mean age of participants was 64 years (range 30-85). A total of 23 stents (13 FCSEMS and 10 BDS) were placed in 12 patients (median 1.92, range 1-4). The technical success rate was 96% (22/23 stents). Eight patients (66.6%) maintained adequate oral intake at the end of follow-up (median 33.3 months, range 3-84 months). Migration was recorded in 7/23 stents (30.4%) and epithelial hyperplasia in 4/23 stents (17.4%). No severe adverse events were noted. All patients complained of minor cervical pain after placement that was well controlled with mild analgesia. Conclusions: Endoscopic stent therapy seems to be effective and safe in the management of RBCES

Bendamustine as part of conditioning of autologous stem cell transplantation in patients with aggressive lymphoma: a phase 2 study from the GELTAMO group

We conducted a phase 2 trial to evaluate the safety and efficacy of bendamustine instead of BCNU (carmustine) in the BEAM (BCNU, etoposide, cytarabine and melphalan) regimen (BendaEAM) as conditioning for autologous stem-cell transplantation (ASCT) in patients with aggressive lymphomas. The primary endpoint was 3-year progression-free survival (PFS). Sixty patients (median age 55 [28–71] years) were included. All patients (except one who died early) engrafted after a median of 11 (9–72) and 14 (4–53) days to achieve neutrophil and platelet counts of >0.5 × 109/l and >20 × 109/l, respectively. Non-relapse mortality at 100 days and 1 year were 3.3% and 6.7%, respectively. With a median follow-up of 67 (40–77) months, the estimated 3-year PFS and overall survival (OS) were 58% and 75%, respectively. Patients in partial response at study entry had significantly worse PFS and OS than patients who underwent ASCT in complete metabolic remission, and this was the only prognostic factor associated with both PFS (Relative risk [RR], 0.27 [95% confidence interval {CI} [0.12–0.56]) and OS (RR, 0.40 [95% CI 0.17–0.97]) in the multivariate analysis. BendaEAM conditioning is therefore a feasible and effective regimen in patients with aggressive lymphomas. However, patients not in complete metabolic remission at the time of transplant had poorer survival and so should be considered for alternative treatment strategies