Long-term mortality in a cohort of severely obese persons in Italy

Few large studies on Northern European or US populations reported on mortality of severely obese individuals (BMI > or = 40 kg/m(2)). We studied a historical cohort in Italy to compare its mortality with previous findings, to investigate its relationship with BMI in the >40 range, and to provide evidence useful for clinical decision-making on treatment. The cohort comprised 4,837 persons with a BMI > or =40 kg/m(2) and aged > or =18 at first consultation, referred to six centers for obesity treatment between 1975 and 1996. After exclusion of persons with missing personal identification data or those untraceable, 4,498 (972 men, 3,526 women) remained for analyses. We calculated standardized mortality ratios (SMRs) and carried out Cox proportional hazards modeling. General mortality (484 deaths: 153 men, 331 women) was in excess, with SMRs (95% confidence intervals) of 2.78 (2.36-3.26) for men and 2.10 (1.88-2.34) for women. Excess mortality (i) was observed in all BMI categories, except among women weighing 40-42.4 kg/m(2); (ii) increased with increasing BMI; (iii) increased less among persons recruited in recent calendar periods; (iv) was inversely related to age attained at follow-up; and (v) was due to cardiovascular and respiratory diseases and violent deaths but not malignant neoplasms. Excess mortality was similar to that observed in Northern European and US cohorts. Its steady increase with BMI levels > or =40 suggests that benefits proportional to weight reduction are expected and that even limited control may be beneficial. The smaller excess among persons recruited most recently might reflect better treatment.     

Species traits explain variation in detectability of UK birds

Capsule Heterogeneous detectability amongst species may impact multi-species bird surveys and if not accounted for, may bias community level conclusions. Estimates of detectability were produced for 195 UK bird species, and detectability was significantly affected by bird size, diet and habitat specialization.

Aims To estimate detectability and understand which species traits may impact detectability.

Methods We estimated the detectability of 195 species of birds in the UK using distance sampling methods and examined the average detectability of genetically related groups. We tested the significance of species traits in describing variation in detectability, whilst controlling for phylogenetic relationships.

Results Passeriformes had the lowest median detectability of 0.37 and Charadriiformes the highest median detectability of 0.65, of the seven largest orders considered. Species most associated with closed habitats such as woodland and urban areas had the lowest detectability. Smaller species had lower detectability than larger species.

Conclusion Heterogeneity in species detectability could lead to biased conclusions, particularly when calculating multi-species indices such as species richness or diversity. Accounting for detectability will be most important in studies that cover a wide range of habitat types or a diverse spread of taxa.     

Interspecific relationships in co‐occurring populations of social parasites and their host ants

Myrmica ant colonies host numerous insect species, including the larvae of Maculinea butterflies and Microdon myrmicae hoverflies. Little is known about the interspecific relationships among these social parasites and their host ants occurring in sympatric populations. We investigated communities of social parasites to assess the strategies allowing them to share the same pool of resources (i.e. Myrmica colonies). The present study was carried out at five sites inhabited by different social parasite communities, each comprising varying proportions of Maculinea teleius, Maculinea nausithous, Maculinea alcon, and Microdon myrmicae. We investigated their spatial distributions, host segregation, the degree of chemical similarity between social parasites and hosts, and temporal overlaps in colony resource exploitation. Spatial segregation among social parasites was found in two populations and it arises from microhabitat preferences and biological interactions. Local conditions can drive selection on one social parasite to use a Myrmica host species that is not exploited by other social parasites. Myrmica scabrinodis and Myrmica rubra nests infested by larvae of two social parasite species were found and the most common co‐occurrence was between Ma. teleius and Mi. myrmicae. The successful coexistence of these two species derives from their exploitation of the host colony resources at different times of the year. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 699–709.     

Arabidopsis CURVATURE THYLAKOID1 Proteins Modify Thylakoid Architecture by Inducing Membrane Curvature

Chloroplasts of land plants characteristically contain grana, cylindrical stacks of thylakoid membranes. A granum consists of a core of appressed membranes, two stroma-exposed end membranes, and margins, which connect pairs of grana membranes at their lumenal sides. Multiple forces contribute to grana stacking, but it is not known how the extreme curvature at margins is generated and maintained. We report the identification of the CURVATURE THYLAKOID1 (CURT1) protein family, conserved in plants and cyanobacteria. The four Arabidopsis thaliana CURT1 proteins (CURT1A, B, C, and D) oligomerize and are highly enriched at grana margins. Grana architecture is correlated with the CURT1 protein level, ranging from flat lobe-like thylakoids with considerably fewer grana margins in plants without CURT1 proteins to an increased number of membrane layers (and margins) in grana at the expense of grana diameter in overexpressors of CURT1A. The endogenous CURT1 protein in the cyanobacterium Synechocystis sp PCC6803 can be partially replaced by its Arabidopsis counterpart, indicating that the function of CURT1 proteins is evolutionary conserved. In vitro, Arabidopsis CURT1A proteins oligomerize and induce tubulation of liposomes, implying that CURT1 proteins suffice to induce membrane curvature. We therefore propose that CURT1 proteins modify thylakoid architecture by inducing membrane curvature at grana margins.     

Immuno-spin trapping of protein and DNA radicals: “Tagging” free radicals to locate and understand the redox process

Biomolecule-centered radicals are intermediate species produced during both reversible (redox modulation) and irreversible (oxidative stress) oxidative modification of biomolecules. These oxidative processes must be studied in situ and in real time to understand the molecular mechanism of cell adaptation or death in response to changes in the extracellular environment. In this regard, we have developed and validated immuno-spin trapping to tag the redox process, tracing the oxidatively generated modification of biomolecules, in situ and in real time, by detecting protein- and DNA-centered radicals. The purpose of this methods article is to introduce and update the basic methods and applications of immuno-spin trapping for the study of redox biochemistry in oxidative stress and redox regulation. We describe in detail the production, detection, and location of protein and DNA radicals in biochemical systems, cells, and tissues, and in the whole animal as well, by using immuno-spin trapping with the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide.     

NUPTs in sequenced eukaryotes and their genomic organization in relation to NUMTs

NUPTs (nuclear plastid DNA) derive from plastid-to-nucleus DNA transfer and exist in various plant species. Experimental data imply that the DNA transfer is an ongoing, highly frequent process, but for the interspecific diversity of NUPTs, no clear explanation exists. Here, an inventory of NUPTs in the four sequenced plastid-bearing species and their genomic organization is presented. Large genomes with a predicted low gene density contain more NUPTs. In Chlamydomonas and Plasmodium, DNA transfer occurred but was limited, probably because of the presence of only one plastid per cell. In Arabidopsis and rice, NUPTs are frequently organized as clusters. Tight clusters can contain both NUPTs and NUMTs (nuclear mitochondrial DNA), indicating that preNUPTs and preNUMTs might have concatamerized before integration. The composition of such a hypothetical preNUPT-preNUMT pool seems to be variable, as implied by substantially different NUPTs:NUMTs ratios in different species. Loose clusters can span several dozens of kbps of nuclear DNA, and they contain markedly more NUPTs or NUMTs than expected from a random genomic distribution of nuclear organellar DNA. The level of sequence similarity between NUPTs/NUMTs and plastid/mitochondrial DNA correlates with the size of the integrant. This implies that original insertions are large and decay over evolutionary time into smaller fragments with diverging sequences. We suggest that tight and loose clusters represent intermediates of this decay process.     

The formation of a salt bridge between helices 3 and 6 is responsible for the constitutive activity and lack of hormone responsiveness of the naturally occurring L457R mutation of the human lutropin receptor

The human lutropin receptor (hLHR) plays a pivotal role in reproductive endocrinology. A number of naturally occurring mutations of the hLHR have been identified that cause the receptor to become constitutively active. To gain further insights into the structural basis for the activation of the hLHR by activating mutations, we chose to examine a particularly strong constitutively activating mutation of this receptor, L457R, in which a leucine that is highly conserved among rhodopsin-like G protein-coupled receptors in helix 3 has been substituted with arginine. Using both disruptive as well as reciprocal mutagenesis strategies, our studies demonstrate that the ability of L457R to stabilize an active form of the hLHR is because of the formation of a salt bridge between the replacing amino acid and Asp-578 in helix 6. Such a lock between the transmembrane portions of helices 3 and 6 is concurrent with weakening the connections between the cytosolic ends of the same helices, including the interaction found in the wild-type receptor between Arg-464, of the (E/D)R(Y/W) motif, and Asp-564. This structural effect is properly marked by the increase in the solvent accessibility of selected amino acids at the cytosolic interfaces between helices 3 and 6. The integrity of the conserved amino acids Asn-615 and Asn-619 in helix 7 is required for the transfer of the structural change from the activating mutation site to the cytosolic interface between helices 3 and 6. The results of in vitro and computational experiments further suggest that the structural trigger of the constitutive activity of the L457R mutant may also be responsible for its lack of hormone responsiveness.     

Arginine methylation analysis of the splicing-associated SR protein SFRS9/SRP30C

The human SFRS9/SRp30c belongs to the SR family of splicing regulators. Despite evidence that members of this protein family may be targeted by arginine methylation, this has yet to be experimentally addressed. In this study, we found that SFRS9 is a target for PRMT1-mediated arginine methylation in vitro, and that it is immunoprecipitated from HEK-293 lysates by antibodies that recognize both mono- and dimethylated arginines. We further observed that upon treatment with the methylation inhibitor Adox, the fluorescent EGFP-SFRS9 re-localizes to dot-like structures in the cell nucleus. In subsequent confocal analyses, we found that EGFP-SFRS9 localizes to nucleoli in Adox-treated cells. Our findings indicate the importance of arginine methylation for the subnuclear localization of SFRS9.     

Comparison of PCR, electrochemical enzyme-linked immunosorbent assays, and the standard culture method for detecting salmonella in meat products

An electrochemical enzyme-linked immunosorbent assay (ELISA) coupled with flow injection analysis (ELISA-FIA) and a PCR-based method using ST11 and ST15 primers for detecting salmonellae in meat were evaluated in comparison with the International Organization for Standardization (ISO) culture method. The methods were applied to experimentally contaminated and naturally contaminated meat samples. The results showed that both ELISA-FIA and PCR allowed detection of salmonella in a product contaminated with a low number of the microorganisms (1 to 10 salmonellae/25 g) after only 5 h of incubation of preenrichment broth, and they were just as effective as the ISO method.     

Helicobacter pylori associated antigastric autoantibodies: role in Sjögren's syndrome gastritis

Background. Previous studies have shown that Helicobacter pylori seroprevalence in Sjögren's syndrome is comparable with that of the general population. However, the origin of the chronic gastropathy associated with this syndrome and the role of local autoimmunity – possibly triggered by bacterial infection – in its pathogenesis remain unclear. Materials and Methods. We initially determined the prevalence of IgG anti H. pylori in dyspeptic subjects with and without Sjögren's syndrome. In subsets of both groups we then determined anti CagA and human tissue‐tested anticanalicular/antifoveolar autoantibodies. We also compared activity, atrophy and Mucosa Associated Lymphoid Tissue (MALT) scores, as well as symptoms, before and after bacterial eradication. Results. Prevalence of H. pylori in Sjögren's syndrome patients was similar to controls: 31/54 (57%) vs. 93/150 (62%). Anti CagA prevalence was also similar in the two groups. Twenty weeks after H. pylori eradication, histological activity decreased in both groups, however, atrophy and MALT decreased significantly only in controls. Sixteen months after H. pylori eradication, 75% of Sjögren's syndrome patients still complained of dyspepsia compared with 13% of controls. Finally, antigastric autoantibodies were present in 29% of tested Sjögren's syndrome patients vs. 28% of controls. Conclusions. H. pylori infection was equally prevalent among dyspeptic Sjögren's syndrome patients and dyspeptic controls. Likewise, there were no differences regarding anti CagA prevalence or antigastric autoantibodies among the two groups. The persistence of symptoms as well as of the lymphocytic infiltration and atrophy after H. pylori eradication in Sjögren's syndrome may underlie the ‘endogenous’ and still unknown nature of the gastropathy in this condition.