Environmental Shaping of Sponge Associated Archaeal Communities

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

Influence of KIR genes and their HLA ligands in susceptibility to dengue in a population from southern Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Killer cell immunoglobulin-like receptors (KIR) form a group of regulatory molecules that specifically recognise human leukocyte antigen (HLA) class I molecules, modulating the cytolytic activity of natural killer cells. The purpose of this study was to investigate the influence of KIR genes and their class I HLA ligands in susceptibility to dengue fever in a population from southern Brazil through a case-control study. One hundred four subjects with confirmed diagnoses of dengue participated in this study, along with a control group of 172 individuals from the same geographic area. HLA and KIR genotyping was performed by polymerase chain reaction with sequence-specific oligonucleotide probes (PCR-SSOP) and with sequence-specific primer (PCR-SSP) techniques, respectively. Data analysis showed significant differences for the KIR2DS1 (54.8% vs 40.7%, P=0.03), KIR2DS5 (50.0% vs 36.0%, P=0.03) and KIR2DL5 (76.0% vs 56.4%, P=0.001) genes. With regard to KIR-ligand pairs, positive associations with dengue were observed in KIR3DS1-Bw4 (45.2% vs 29.7%, P=0.01), KIR3DL1-Bw4 (80.7% vs 65.1%, P<0.001), KIR2DL1-C2 (75.0% vs 62.2%, P=0.03) and KIR2DS1-C2 (40.4% vs 25.6%, P=0.01) interactions, and a negative association in KIR2DL3-C1/C1 (18.2% vs 33.1%, P = 0.01). Furthermore, the analysis of KIR haplogroups showed a possible protective factor against dengue fever in individuals with the AA genotype. Taken together, these results suggest the existence of genetic predisposition to dengue fever in the population from southern Brazil.826397404Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Laboratory of Immunogenetics at the Universidade Estadual de MaringaCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES