RESUMO
Fundamental to holobiont biology is recognising how variation in microbial composition and function relates to host phenotypic variation. Sponges often exhibit considerable phenotypic plasticity and also harbour dense microbial communities that function to protect and nourish hosts. One of the most prominent sponge genera on Caribbean coral reefs is Agelas. Using a comprehensive set of morphological (growth form, spicule), chemical and molecular data on 13 recognised species of Agelas in the Caribbean basin, we were able to define only five species (=clades) and found that many morphospecies designations were incongruent with phylogenomic and population genetic analyses. Microbial communities were also strongly differentiated between phylogenetic species, showing little evidence of cryptic divergence and relatively low correlation with morphospecies assignment. Metagenomic analyses also showed strong correspondence to phylogenetic species, and to a lesser extent, geographical and morphological characters. Surprisingly, the variation in secondary metabolites produced by sponge holobionts was explained by geography and morphospecies assignment, in addition to phylogenetic species, and covaried significantly with a subset of microbial symbionts. Spicule characteristics were highly plastic, under greater impact from geographical location than phylogeny. Our results suggest that while phenotypic plasticity is rampant in Agelas, morphological differences within phylogenetic species affect functionally important ecological traits, including the composition of the symbiotic microbial communities and metabolomic profiles.
Assuntos
Agelas , Poríferos , Animais , Filogenia , Região do Caribe , Índias Ocidentais , Recifes de Corais , Poríferos/genéticaRESUMO
Ostracods collected from shallow coral reefs in the Bahamas were found to exhibit blue light-stimulated orange fluorescence at night. Fluorescent spectra revealed the presence of orange fluorescence with a maximum emission at ~595 nm on the carapace of these ostracods, while scanning electron microscopy revealed a morphologically diverse microbial community covering the entire carapace of these ostracods. Pyrosequencing and cyanobacterial-specific 16S rRNA sequencing reveals that this epibiont community is highly diverse and highly variable between individual ostracods. Many species of Cyanobacteria in the orders Oscillatoriales and Chroococcales, as well as other Proteobacteria and diatom chloroplast sequences, were identified using the cyanobacterial-specific primers. While no fluorescent proteins or phycoerythrin were detected in these ostracods, it is possible that the observed orange fluorescence is the result of carotenoid fluorescence from Cyanobacteria. The microbial consortium forms an epibiotic biofilm on the carapace of these ostracods whose functions are unknown.
Assuntos
Biofilmes , Crustáceos/microbiologia , Cianobactérias/isolamento & purificação , Diatomáceas/isolamento & purificação , Fluorescência , Proteobactérias/isolamento & purificação , Animais , Bahamas , Recifes de Corais , Crustáceos/ultraestrutura , Cianobactérias/classificação , Cianobactérias/genética , Cianobactérias/fisiologia , DNA Bacteriano/genética , Diatomáceas/classificação , Diatomáceas/genética , Diatomáceas/fisiologia , Metagenoma , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/fisiologia , RNA Ribossômico 16S/genéticaRESUMO
To determine whether survival of patients with beta-thalassemia major has been prolonged by management that utilizes hypertransfusion and chelation with deferoxamine, we analyzed longevity by the Kaplan-Meier product-limit method. Group 1 patients (n = 71) followed between 1960 and 1976 with a low-transfusion regimen (pretransfusion hemoglobin level 7 to 8 gm/dl) and no chelation had an estimated median age of survival of 17.4 years, whereas it was 31.0 years for group 2 subjects (n = 80), who began hypertransfusion between 1976 and 1978 (pretransfusion hemoglobin level 10.5 to 11.5 gm/dl) and chelation with deferoxamine (20 to 60 mg/kg per day) (p less than 0.0001). For 70 patients who were treated with hypertransfusion and deferoxamine, we had data to calculate the ratio of total milligrams of transfusional iron to cumulative grams of deferoxamine. The 24 patients who died had a total iron burden of greater than 1.05 gm/kg; the ratio for them exceeded 31. These patients were characterized by poor compliance with chelation or by late start of therapy, with inability to receive enough deferoxamine before death. Death was preceded by arrhythmia requiring therapy in all but one, and by cardiac failure in all. Of 41 similarly iron-loaded survivors, 33 had a ratio of less than 31; only three had an arrhythmia, and five had cardiac failure. We conclude that treatment with deferoxamine, when used in amounts proportional to iron burden, delayed cardiac complications and improved longevity.