Herbaspirillum seropedicae rfbB and rfbC genes are required for maize colonization

In this study we disrupted two Herbaspirillum seropedicae genes, rfbB and rfbC, responsible for rhamnose biosynthesis and its incoporation into LPS. GC-MS analysis of the H. seropedicae wild-type strain LPS oligosaccharide chain showed that rhamnose, glucose and N-acetyl glucosamine are the predominant monosaccharides, whereas rhamnose and N-acetyl glucosamine were not found in the rfbB and rfbC strains. The electrophoretic pattern of the mutants LPS was drastically altered when compared with the wild type. Knockout of rfbB or rfbC increased the sensitivity towards SDS, polymyxin B sulfate and salicylic acid. The mutants attachment capacity to maize root surface plantlets was 100-fold lower than the wild type. Interestingly, the wild-type capacity to attach to maize roots was reduced to a level similar to that of the mutants when the assay was performed in the presence of isolated wild-type LPS, glucosamine or N-acetyl glucosamine. The mutant strains were also significantly less efficient in endophytic colonization of maize. Expression analysis indicated that the rfbB gene is upregulated by naringenin, apigenin and CaCl(2). Together, the results suggest that intact LPS is required for H. seropedicae attachment to maize root and internal colonization of plant tissues.     

Novel primate-specific genes, RMEL 1, 2 and 3, with highly restricted expression in melanoma, assessed by new data mining tool

Melanoma is a highly aggressive and therapy resistant tumor for which the identification of specific markers and therapeutic targets is highly desirable. We describe here the development and use of a bioinformatic pipeline tool, made publicly available under the name of EST2TSE, for the in silico detection of candidate genes with tissue-specific expression. Using this tool we mined the human EST (Expressed Sequence Tag) database for sequences derived exclusively from melanoma. We found 29 UniGene clusters of multiple ESTs with the potential to predict novel genes with melanoma-specific expression. Using a diverse panel of human tissues and cell lines, we validated the expression of a subset of three previously uncharacterized genes (clusters Hs.295012, Hs.518391, and Hs.559350) to be highly restricted to melanoma/melanocytes and named them RMEL1, 2 and 3, respectively. Expression analysis in nevi, primary melanomas, and metastatic melanomas revealed RMEL1 as a novel melanocytic lineage-specific gene up-regulated during melanoma development. RMEL2 expression was restricted to melanoma tissues and glioblastoma. RMEL3 showed strong up-regulation in nevi and was lost in metastatic tumors. Interestingly, we found correlations of RMEL2 and RMEL3 expression with improved patient outcome, suggesting tumor and/or metastasis suppressor functions for these genes. The three genes are composed of multiple exons and map to 2q12.2, 1q25.3, and 5q11.2, respectively. They are well conserved throughout primates, but not other genomes, and were predicted as having no coding potential, although primate-conserved and human-specific short ORFs could be found. Hairpin RNA secondary structures were also predicted. Concluding, this work offers new melanoma-specific genes for future validation as prognostic markers or as targets for the development of therapeutic strategies to treat melanoma.     

Environmental shaping of sponge associated archaeal communities

Background

Archaea are ubiquitous symbionts of marine sponges but their ecological roles and the influence of environmental factors on these associations are still poorly understood.

Methodology/Principal Findings

We compared the diversity and composition of archaea associated with seawater and with the sponges Hymeniacidon heliophila, Paraleucilla magna and Petromica citrina in two distinct environments: Guanabara Bay, a highly impacted estuary in Rio de Janeiro, Brazil, and the nearby Cagarras Archipelago. For this we used metagenomic analyses of 16S rRNA and ammonia monooxygenase (amoA) gene libraries. Hymeniacidon heliophila was more abundant inside the bay, while P. magna was more abundant outside and P. citrina was only recorded at the Cagarras Archipelago. Principal Component Analysis plots (PCA) generated using pairwise unweighted UniFrac distances showed that the archaeal community structure of inner bay seawater and sponges was different from that of coastal Cagarras Archipelago. Rarefaction analyses showed that inner bay archaeaoplankton were more diverse than those from the Cagarras Archipelago. Only members of Crenarchaeota were found in sponge libraries, while in seawater both Crenarchaeota and Euryarchaeota were observed. Although most amoA archaeal genes detected in this study seem to be novel, some clones were affiliated to known ammonia oxidizers such as Nitrosopumilus maritimus and Cenarchaeum symbiosum.

Conclusion/Significance

The composition and diversity of archaeal communities associated with pollution-tolerant sponge species can change in a range of few kilometers, probably influenced by eutrophication. The presence of archaeal amoA genes in Porifera suggests that Archaea are involved in the nitrogen cycle within the sponge holobiont, possibly increasing its resistance to anthropogenic impacts. The higher diversity of Crenarchaeota in the polluted area suggests that some marine sponges are able to change the composition of their associated archaeal communities, thereby improving their fitness in impacted environments.     

Swimming training induces liver adaptations to oxidative stress and insulin sensitivity in rats submitted to high-fat diet

Oxidative stress, physical inactivity and high-fat (FAT) diets are associated with hepatic disorders such as metabolic syndrome (MS). The therapeutic effects of physical training (PT) were evaluated in rats with MS induced by FAT diet for 13 weeks, on oxidative stress and insulin signaling in the liver, during the last 6 weeks. FAT-sedentary (SED) rats increased body mass, retroperitoneal fat, mean arterial pressure (MAP) and heart rate (HR), and total cholesterol, serum alanine aminotransferase, glucose and insulin. Livers of FAT-SED rats increased superoxide dismutase activity, thiobarbituric acid-reactive substances, protein carbonyl and oxidized glutathione (GSSG); and decreased catalase activity, reduced glutathione/GSSG ratio, and the mRNA expression of insulin receptor substrate 1 (IRS-1) and serine/threonine kinase 2. FAT-PT rats improved in fitness and reduced their body mass, retroperitoneal fat, and glucose, insulin, total cholesterol, MAP and HR; and their livers increased superoxide dismutase and catalase activities, the reduced glutathione/GSSG ratio and the expression of peroxisome proliferator-activated receptor gamma and insulin receptor compared to FAT-SED rats. These findings indicated adaptive responses to PT by restoring the oxidative balance and insulin signaling in the liver and certain biometric and biochemical parameters as well as MAP in MS rats.     

HLA-typing analysis following allogeneic bone grafting for sinus lifting

According to the Brazilian Association of Organ Transplants, in 2015, 19,408 bone transplants were performed in Brazil, over 90% by Dental Surgeons. The surgical technique itself has a respectable number of reports regarding its clinical efficacy, as measured by long-term survival of dental implants in grafted areas. Uncertainty remains, however, as to whether fresh frozen grafts from human bone donors remain immunologically innocuous in the body of the host. Six male with no previous medical history of note, including systemic diseases, surgery or blood transfusion were selected. These patients underwent reconstructive procedures (sinus lifting) using fresh frozen human bone from a tissue bank. All patients had venous blood samples collected prior to surgery and 6 months after the procedure. Anti-HLA analysis for the detection of HLA (human leukocyte antigen) antibodies was performed using methods such as the LABScreen PRA Class I and Class II, LABScreen Single Antigen Class I and Class II, Luminex Platform. Reactive individuals to the screening tests (LABScreen PRA) were further investigated to determine the specificity of the antibodies detected (LABScreen Single Antigen) with a cutoff value of median fluorescence intensity ≥500. As a result, it was observed that two patients (33%) were positive in screening tests, one presenting with anti-HLA Class I and II sensitization and the other with anti-HLA class II. The specificity analysis showed that the patients sensitized to HLA class II presented 4 specificities, 3 of which immunologically relevant. In the second individual, 23 specificities were identified, 6 of which immunologically important for HLA class I and 4 specificities for HLA class II, 3 of these were immunologically important. All specificities detected had average fluorescence. These findings are suggestive that sinus-lifting procedures with allogeneic bone can induce immunological sensitization.     

The MCT1 gene Glu490Asp polymorphism (rs1049434) is associated with endurance athlete status,lower blood lactate accumulation and higher maximum oxygen uptake

The purpose of this study was to explore the association of the MCT1 gene Glu490Asp polymorphism (rs1049434) with athletic status and performance of endurance athletes. A total of 1,208 Brazilians (318 endurance athletes and 890 non-athletes) and 867 Europeans (315 endurance athletes and 552 non-athletes) were evaluated in a case–control approach. Brazilian participants were classified based on self-declared ethnicity to test whether the polymorphism was different between Caucasians and Afro-descendants. Moreover, 66 Hungarian athletes underwent an incremental test until exhaustion to assess blood lactate levels, while 46 Russian athletes had their maximum oxygen uptake (V⋅O2max ) compared between genotypes. In the Brazilian cohort, the major T-allele was more frequent in Caucasian top-level competitors compared to their counterparts of lower competitive level (P = 0.039), and in Afro-descendant athletes compared to non-athletes (P = 0.015). Similarly, the T-allele was more frequent in European athletes (P = 0.029). Meta-analysis of the Brazilian and European cohorts confirmed that the T-allele is over-represented in endurance athletes (OR: 1.48, P = 0.03), especially when Afro-descendant athletes were included in the meta-analysis (OR: 1.58, P = 0.005). Furthermore, carriers of the T/T genotype accumulated less blood lactate in response to intense effort (P < 0.01) and exhibited higher V⋅O2max (P = 0.04)_. In conclusion, the Glu490Asp polymorphism was associated with endurance athletic status and performance. Our findings suggest that, although ethnic differences may exist, the presence of the major T-allele (i.e., the Glu-490 allele) favours endurance performance more than the mutant A-allele (i.e., the 490-Asp allele).     

Conservation implications of genetic structure in the narrowest endemic quillwort from the Eastern Amazon

The quillwort Isoëtes cangae is a critically endangered species occurring in a single lake in Serra dos Carajás, Eastern Amazon. Low genetic diversity and small effective population sizes (N _e) are expected for narrow endemic species (NES). Conservation biology studies centered in a single species show some limitations, but they are still useful considering the limited time and resources available for protection of species at risk of extinction. Here, we evaluated the genetic diversity, population structure, N _e, and minimum viable population (MVP) of I. cangae to provide information for effective conservation programs. Our analyses were based on 55 individuals collected from the Amendoim Lake and 35,638 neutral SNPs. Our results indicated a single panmictic population, moderate levels of genetic diversity, and N _e in the order of thousands, contrasting the expected for NES. Negative F_IS values were also found, suggesting that I. cangae is not under risk of inbreeding depression. Our findings imply that I. cangae contains enough genetic diversity to ensure evolutionary potential and that all individuals should be treated as one demographic unit. These results provide essential information to optimize ex situ conservation efforts and genetic diversity monitoring, which are currently applied to guide I. cangae conservation plans.     

Role of luteinizing hormone in changes in concentrations of progesterone and luteal blood flow during the hours of a simulated pulse of 13,14-dihydro-15-keto-prostaglandin F(2alpha) (PGFM) in heifers

A bolus treatment (e.g., 25 mg) of prostaglandin F(2alpha) (PGF) in the study of luteolysis in cattle results in dubious interpretations. Therefore, in experiment 1 of the present study, a 13,14-dihydro-15-keto-PGF (PGFM) pulse was simulated by incremental intrauterine (IU) infusion of PGF for 2.7 h on Day 14 postovulation. Concentrations of PGFM during the first hour of infusion and at the maximum were not different between simulated (n = 7) and spontaneous (n = 7) pulses. In experiment 2, four groups (n = 6 per group) were treated at Minute 0 (beginning of infusion) as follows: saline (infused IU), PGF (infused IU), acyline/saline, and acyline/PGF. Two hours before Minute 0, each heifer was given flunixin meglumine to inhibit endogenous PGF secretion, and heifers in the acyline/saline and acyline/PGF groups were given acyline to inhibit luteinizing hormone (LH). Plasma progesterone concentrations were similar among groups during Minutes 0 to 60, with no indication of an initial transient progesterone increase in the two PGF groups. Progesterone began to decrease in the PGF groups at Minute 60 and to rebound at Minute 135 after the PGFM peak at Minute 120. The rebound was complete in association with an increase in LH in the PGF group, but it was not complete when LH was inhibited in the acyline/PGF group. Luteal blood flow increased during PGF infusion in the two PGF groups and remained elevated for approximately 2 h after the PGFM peak in the PGF group but not in the acyline/PGF group. Novel findings were that an initial transient increase in progesterone did not occur with the simulated PGFM pulse and that LH stimulated a progesterone rebound and maintained the elevated luteal blood flow after the PGFM peak.