From friends to foes: fungi could be emerging marine sponge pathogens under global change scenarios

Global change, experienced in the form of ocean warming and pollution by man-made goods and xenobiotics, is rapidly affecting reef ecosystems and could have devastating consequences for marine ecology. Due to their critical role in regulating marine food webs and trophic connections, sponges are an essential model for studying and forecasting the impact of global change on reef ecosystems. Microbes are regarded as major contributors to the health and survival of sponges in marine environments. While most culture-independent studies on sponge microbiome composition to date have focused on prokaryotic diversity, the importance of fungi in holobiont behavior has been largely overlooked. Studies focusing on the biology of sponge fungi are uncommon. Thus, our current understanding is quite limited regarding the interactions and “crosstalk” between sponges and their associated fungi. Anthropogenic activities and climate change may reveal sponge-associated fungi as novel emerging pathogens. Global change scenarios could trigger the expression of fungal virulence genes and unearth new opportunistic pathogens, posing a risk to the health of sponges and severely damaging reef ecosystems. Although ambitious, this hypothesis has not yet been proven. Here we also postulate as a pioneering hypothesis that manipulating sponge-associated fungal communities may be a new strategy to cope with the threats posed to sponge health by pathogens and pollutants. Additionally, we anticipate that sponge-derived fungi might be used as novel sponge health promoters and beneficial members of the resident sponge microbiome in order to increase the sponge's resistance to opportunistic fungal infections under a scenario of global change

Diversity of culturable bacteria recovered from Pico Bolívar’s glacial and subglacial environments,at 4950 m,in Venezuelan tropical Andes

Even though tropical glaciers are retreating rapidly and many will disappear in the next few years,their microbial diversity remains to be studied in depth. In this paper we report on the biodiversity of the culturable fraction of bacteria colonizing Pico Bolívar’s glacier ice and subglacial meltwaters,at ~4950 m in the Venezuelan Andean Mountains. Microbial cells of diverse morphologies and exhibiting uncompromised membranes were present at densities ranging from 1.5 × 104 to 4.7 × 104 cells/mL in glacier ice and from 4.1 × 105 to 9.6 × 105 cells/mL in subglacial meltwater. Of 89 pure isolates recovered from the samples,the majority were eurypsychrophilic or stenopsychrophilic,according to their temperature range of growth. Following analysis of their 16S rDNA nucleotidic sequence,54 pure isolates were assigned to 23 phylotypes distributed within 4 different phyla or classes: Beta- and Gammaproteobacteria,Actinobacteria,and Bacteroidetes. Actinobacteria dominated the culturable fraction of glacier ice samples,whereas Proteobacteria were dominant in subglacial meltwater samples. Chloramphenicol and ampicillin resistance was exhibited by 73.07% and 65.38%,respectively,of the subglacial isolates,and nearly 35% of them were multiresistant. Considering the fast rate at which tropical glaciers are melting,this study confirms the urgent need to study the microbial communities immured in such environments

Etude de l'opéron rus, codant pour sept protéines transporteurs d'électrons, chez la bactérie acidophile, chimioautotrophe obligatoire, Acidithiobacillus ferrooxidans

AIX-MARSEILLE2-BU Sci.Luminy (130552106) / SudocSudocFranceF

Memorias IX Congreso Geológico Venezolano (3)

Memorias IX Congreso Geológico Venezolano (3