Validity and reliability of two brief physical activity questionnaires among Spanish-speaking individuals of Mexican descent

Background

Klebsiella pneumoniae is a leading cause of hospital-acquired urinary tract infections and pneumonia worldwide, and is responsible for many cases of pyogenic liver abscess among diabetic patients in Asia. A defining characteristic of this pathogen is the presence of a thick, exterior capsule that has been reported to play a role in biofilm formation and to protect the organism from threats such antibiotics and host immune challenge.

Findings

We constructed two knockout mutants of K. pneumoniae to investigate how perturbations to capsule biosynthesis alter the cellular phenotype. In the first mutant, we deleted the entire gene cluster responsible for biosynthesis of the extracellular polysaccharide capsule. In the second mutant, we deleted the capsule export subsystem within this cluster. We find that both knockout mutants have lower amounts of capsule but produce greater amounts of biofilm. Moreover, one of the two mutants abolishes fimbriae expression as well.

Conclusions

These results are expected to provide insight into the interaction between capsule biosynthesis, biofilm formation, and fimbriae expression in this organism.     

Connexin43 phosphorylation and cytoprotection in the heart

The fundamental role played by connexins including connexin43 (Cx43) in forming intercellular communication channels (gap junctions), ensuring electrical and metabolic coupling between cells, has long been recognized and extensively investigated. There is also increasing recognition that Cx43, and other connexins, have additional roles, such as the ability to regulate cell proliferation, migration, and cytoprotection. Multiple phosphorylation sites, targets of different signaling pathways, are present at the regulatory, C-terminal domain of Cx43, and contribute to constitutive as well as transient phosphorylation Cx43 patterns, responding to ever-changing environmental stimuli and corresponding cellular needs. The present paper will focus on Cx43 in the heart, and provide an overview of the emerging recognition of a relationship between Cx43, its phosphorylation pattern, and development of resistance to injury. We will also review our recent work regarding the role of an enhanced phosphorylation state of Cx43 in cardioprotection. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.     

Choline transporter‐like protein 4 (CTL4) links to non‐neuronal acetylcholine synthesis

Synthesis of acetylcholine (ACh) by non‐neuronal cells is now well established and plays diverse physiologic roles. In neurons, the Na⁺‐dependent, high affinity choline transporter (CHT1) is absolutely required for ACh synthesis. In contrast, some non‐neuronal cells synthesize ACh in the absence of CHT1 indicating a fundamental difference in ACh synthesis compared to neurons. The aim of this study was to identify choline transporters, other than CHT1, that play a role in non‐neuronal ACh synthesis. ACh synthesis was studied in lung and colon cancer cell lines focusing on the choline transporter‐like proteins, a five gene family choline‐transporter like protein (CTL)1–5. Supporting a role for CTLs in choline transport in lung cancer cells, choline transport was Na⁺‐independent and CTL1–5 were expressed in all cells examined. CTL1, 2, and 5 were expressed at highest levels and knockdown of CTL1, 2, and 5 decreased choline transport in H82 lung cancer cells. Knockdowns of CTL1, 2, 3, and 5 had no effect on ACh synthesis in H82 cells. In contrast, knockdown of CTL4 significantly decreased ACh secretion by both lung and colon cancer cells. Conversely, increasing expression of CTL4 increased ACh secretion. These results indicate that CTL4 mediates ACh synthesis in non‐neuronal cell lines and presents a mechanism to target non‐neuronal ACh synthesis without affecting neuronal ACh synthesis.     

A complex species complex: The controversial role of ecology and biogeography in the evolutionary history of Syllis gracilis Grube, 1840 (Annelida,Syllidae)

The cryptic diversity in the polychaete Syllis gracilis Grube, 1840, in the Mediterranean Sea was examined with an integrative morpho-molecular approach. Individuals of S. gracilis were collected at eleven Mediterranean localities to provide an insight into the role of brackish environments in inducing cryptic speciation. The examination of morphological features combined with a molecular genetic analysis based on a partial sequence of the 16S rRNA gene highlighted discrepancies between morphological and molecular diversity. Morphological data allowed to identify a morphotype with short appendages occurring in coralline algae communities and another one with long appendages observed in brackish-water environments and Sabellaria reefs. Multivariate analyses showed that sampling localities were the greatest source of morphological divergence, suggesting that phenotypic plasticity may play a role in local adaptations of S. gracilis populations. Molecular data showed the occurrence of four divergent lineages not corresponding to morphological clusters. Different species delimitation tests gave conflicting results, retrieving, however, at least four separated entities. Some lineages occurred in sympatry and were equally distributed in marine and brackish-water environments, excluding a biogeographic or ecological explanation of the observed pattern and suggesting instead ancient separation between lineages and secondary contact. The co-occurrence of different lineages hindered the identification of the lineage corresponding to S. gracilis sensu stricto. The discrepancy between morphological and molecular diversity suggests that different environmental and biogeographic features may interact in a complex and unpredictable way in shaping diversity patterns. An integrative approach is needed to provide a satisfactory insight on evolutionary processes in marine invertebrates.     

Electronic Tagging of Atlantic Bluefin Tuna (Thunnus thynnus,L.) Reveals Habitat Use and Behaviors in the Mediterranean Sea

We analyzed the movements of Atlantic tuna (Thunnus thynnus L.) in the Mediterranean Sea using data from 2 archival tags and 37 pop-up satellite archival tags (PAT). Bluefin tuna ranging in size from 12 to 248 kg were tagged on board recreational boats in the western Mediterranean and the Adriatic Sea between May and September during two different periods (2000 to 2001 and 2008 to 2012). Although tuna migrations between the Mediterranean Sea and the Atlantic Ocean have been well reported, our results indicate that part of the bluefin tuna population remains in the Mediterranean basin for much of the year, revealing a more complex population structure. In this study we demonstrate links between the western Mediterranean, the Adriatic and the Gulf of Sidra (Libya) using over 4336 recorded days of location and behavior data from tagged bluefin tuna with a maximum track length of 394 days. We described the oceanographic preferences and horizontal behaviors during the spawning season for 4 adult bluefin tuna. We also analyzed the time series data that reveals the vertical behavior of one pop-up satellite tag recovered, which was attached to a 43.9 kg tuna. This fish displayed a unique diving pattern within 16 days of the spawning season, suggesting a use of the thermocline as a thermoregulatory mechanism compatible with spawning. The results obtained hereby confirm that the Mediterranean is clearly an important habitat for this species, not only as spawning ground, but also as an overwintering foraging ground.     

Identification of NF-κB and PLCL2 as new susceptibility genes and highlights on a potential role of IRF8 through interferon signature modulation in systemic sclerosis

IntroductionSystemic sclerosis (SSc) and primary biliary cirrhosis (PBC) are rare polygenic autoimmune diseases (AIDs) characterized by fibroblast dysfunction. Furthermore, both diseases share some genetic bases with other AIDs, as evidenced by autoimmune gene pleiotropism. The present study was undertaken to investigate whether single-nucleotide polymorphisms (SNPs) identified by a large genome-wide association study (GWAS) in PBC might contribute to SSc susceptibility.MethodsSixteen PBC susceptibility SNPs were genotyped in a total of 1,616 patients with SSc and 3,621 healthy controls from two European populations (France and Italy).ResultsWe observed an association between PLCL2 rs1372072 (odds ratio (OR) = 1.22, 95% confidence interval (CI) 1.12 to 1.33, P_adj = 7.22 × 10⁻⁵), nuclear factor-kappa-B (NF-κB) rs7665090 (OR = 1.15, 95% CI 1.06 to 1.25, P_adj = 0.01), and IRF8 rs11117432 (OR = 0.75, 95% CI 0.67 to 0.86, P_adj = 2.49 × 10⁻⁴) with SSc susceptibility. Furthermore, phenotype stratification showed an association between rs1372072 and rs11117432 with the limited cutaneous subgroup (lcSSc) (P_adj = 4.45 × 10⁻⁴ and P_adj = 0.001), whereas rs7665090 was associated with the diffuse cutaneous subtype (dcSSc) (P_adj = 0.003). Genotype-mRNA expression correlation analysis revealed that the IRF8 protective allele was associated with increased interferon-gamma (IFN-γ) expression (P = 0.03) in patients with SSc but decreased type I IFN (IFIT1) expression in patients and controls (P = 0.02). In addition, we found an epistatic interaction between NF-κB and IRF8 (OR = 0.56, 95% CI 0.00 to 0.74, P = 4 × 10⁻⁴) which in turn revealed that the IRF8 protective effect is dependent on the presence of the NF-κB susceptibility allele.ConclusionsAn analysis of pleiotropic genes identified two new susceptibility genes for SSc (NF-κB and PLCL2) and confirmed the IRF8 locus. Furthermore, the IRF8 variant influenced the IFN signature, and we found an interaction between IRF8 and NF-κB gene variants that might play a role in SSc susceptibility.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0572-y) contains supplementary material, which is available to authorized users.     

Characterization of a thermoactive endoglucanase isolated from a biogas plant metagenome

A metagenomic library from DNA isolated from a biogas plant was constructed and screened for thermoactive endoglucanases to gain insight into the enzymatic diversity involved in plant biomass breakdown at elevated temperatures. Two cellulase-encoding genes were identified and the corresponding proteins showed sequence similarities of 59% for Cel5A to a putative cellulase from Anaerolinea thermolimosa and 99% for Cel5B to a characterized endoglucanase isolated from a biogas plant reactor. The cellulase Cel5A consists of one catalytical domain showing sequence similarities to glycoside hydrolase family 5 and comprises 358 amino acids with a predicted molecular mass of 41.2 kDa. The gene coding for cel5A was successfully cloned and expressed in Escherichia coli C43(DE3). The recombinant protein was purified to homogeneity using affinity chromatography with a specific activity of 182 U/mg, and a yield of 74%. Enzymatic activity was detectable towards cellulose and mannan containing substrates and over a broad temperature range from 40 °C to 70 °C and a pH range from 4.0 to 7.0 with maximal activity at 55 °C and pH 5.0. Cel5A showed high thermostability at 60 °C without loss of activity after 24 h. Due to the enzymatic characteristics, Cel5A is an attractive candidate for the degradation of lignocellulosic material.

     

Role of the MexAB-OprM efflux pump of Pseudomonas aeruginosa in tolerance to tea tree (Melaleuca alternifolia) oil and its monoterpene components terpinen-4-ol, 1,8-cineole, and alpha-terpineol

Using a series of efflux mutants of Pseudomonas aeruginosa, the MexAB-OprM pump was identified as contributing to this organism's tolerance to the antimicrobial agent tea tree (Melaleuca alternifolia) oil and its monoterpene components terpinen-4-ol, 1,8-cineole, and alpha-terpineol. These data show that a multidrug efflux system of P. aeruginosa can extrude monoterpenes and related alcohols.     

Effects of decapitation and ovariectomy on the regulation of juvenile hormone synthesis in the cockroach, Diploptera punctata

Corpora allata from Diploptera punctata females at adult ecdysis or at the end of the last-larval stadium, when implanted into decapitated females, underwent a cycle of juvenile hormone synthesis similar in timing and magnitude to that of glands implanted into control animals which had been starved and allatectomized. Starvation did not alter the cycle in rates of juvenile hormone synthesis of sham-operated animals.Decapitation of ovariectomized animals resulted in no cycle in rates of juvenile hormone synthesis by implanted adult corpora allata; however, implantation of an ovary along with the corpora allata into decapitated, ovariectomized hosts resulted in a cycle of juvenile hormone synthesis. In control animals, which retained their heads but were starved and allatectomized as well as ovariectomized, the implanted corpora allata showed a cycle of juvenile hormone synthesis only when implanted with an ovary. The maximal rates of juvenile hormone synthesis by the corpora allata in both experimental and control conditions were lower than normal, likely due to the repeated trauma of surgery. However, at no time from eclosion to the end of the first gonotrophic period was the brain necessary for the cyclic response of the corpora allata to the presence of the ovary.     

Characterization of the full‐length human Grb7 protein and a phosphorylation representative mutant

It is well known the dimerization state of receptor tyrosine kinases (RTKs), in conjunction with binding partners such as the growth factor receptor bound protein 7 (Grb7) protein, plays an important role in cell signaling regulation. Previously, we proposed, downstream of RTKs, that the phosphorylation state of Grb7SH2 domain tyrosine residues could control Grb7 dimerization, and dimerization may be an important regulatory step in Grb7 binding to RTKs. In this manner, additional dimerization‐dependent regulation could occur downstream of the membrane‐bound kinase in RTK‐mediated signaling pathways. Extrapolation to the full‐length (FL) Grb7 protein, and the ability to test this hypothesis further, has been hampered by the availability of large quantities of pure and stable FL protein. Here, we report the biophysical characterization of the FL Grb7 protein and also a mutant representing a tyrosine‐phosphorylated Grb7 protein form. Through size exclusion chromatography and analytical ultracentrifugation, we show the phosphorylated‐tyrosine‐mimic Y492E‐FL‐Grb7 protein (Y492E‐FL‐Grb7) is essentially monomeric at expected physiological concentrations. It has been shown previously the wild‐type FL Grb7(WT‐FLGrb7) protein is dimeric with a dissociation constant (Kd) of approximately 11μM. Our studies here measure a FL protein dimerization K_d of WT‐FL‐Grb7 within one order of magnitude at approximately 1μM. The approximate size and shape of the WT‐FL‐Grb7 in comparison the tyrosine‐phosphorylation mimic Y492E‐FL‐Grb7 protein was determined by dynamic light scattering methods. In vitro phosphorylation of the Grb7SH2 domain indicates only one of the available tyrosine residues is phosphorylated, suggesting the same phosphorylation pattern could be relevant in the FL protein. The biophysical characterization studies in total are interpreted with a view towards understanding the functionally active Grb7 protein conformation.