Correlation of methane production with physiological traits in IMS 101 grown with methylphosphonate at different temperatures.

The diazotrophic cyanobacterium has been recognized as a potentially significant contributor to aerobic methane generation via several mechanisms including the utilization of methylphophonate (MPn) as a source of phosphorus. Currently, there is no information about how environmental factors regulate methane production by . Here, we grew IMS101 at five temperatures ranging from 16 to 31°C, and found that its methane production rates increased with rising temperatures to peak (1.

, a Bacterial Endophyte of the Marine Macroalga , Emits 8-Nonenoic Acid Which Inhibits the Aquaculture Pathogen .

Secondary metabolites-organic compounds that are often bioactive-produced by endophytes, among others, provide a selective advantage by increasing the organism's survivability. Secondary metabolites mediate the symbiotic relationship between endophytes and their host, potentially providing the host with tolerance to, and protection against biotic and abiotic stressors. Secondary metabolites can be secreted as a dissolved substance or emitted as a volatile.

Diazotrophs are overlooked contributors to carbon and nitrogen export to the deep ocean.

Diazotrophs are widespread microorganisms that alleviate nitrogen limitation in 60% of our oceans, thereby regulating marine productivity. Yet, the group-specific contribution of diazotrophs to organic matter export has not been quantified, which so far has impeded an accurate assessment of their impact on the biological carbon pump. Here, we examine the fate of five groups of globally-distributed diazotrophs by using an original combination of mesopelagic particle sampling devices across the subtropical South Pacific Ocean.

Trichodesmium erythraeum produces a higher photocurrent than other cyanobacterial species in bio-photo electrochemical cells.

The increase in world energy consumption, and the worries from potential future disasters that may derive from climate change have stimulated the development of renewable energy technologies. One promising method is the utilization of whole photosynthetic cyanobacterial cells to produce photocurrent in a bio-photo electrochemical cell (BPEC). The photocurrent can be derived from either the respiratory or photosynthetic pathways, via the redox couple NADP/NADPH mediating cyclic electron transport between photosystem I inside the cells, and the anode.

Sinking Trichodesmium fixes nitrogen in the dark ocean.

The photosynthetic cyanobacterium Trichodesmium is widely distributed in the surface low latitude ocean where it contributes significantly to N fixation and primary productivity. Previous studies found nifH genes and intact Trichodesmium colonies in the sunlight-deprived meso- and bathypelagic layers of the ocean (200-4000 m depth). Yet, the ability of Trichodesmium to fix N in the dark ocean has not been explored.

Metagenomes of Red Sea Subpopulations Challenge the Use of Marker Genes and Morphology to Assess Diversity.

are filamentous cyanobacteria of key interest due to their ability to fix carbon and nitrogen within an oligotrophic marine environment. Their blooms consist of a dynamic assemblage of subpopulations and colony morphologies that are hypothesized to occupy unique niches. Here, we assessed the poorly studied diversity of in the Red Sea, based on metagenome-assembled genomes (MAGs) and gene-based phylotyping.

Fine-scale sampling unveils diazotroph patchiness in the South Pacific Ocean.

Diazotrophs are important contributors to nitrogen availability in the ocean. Oceanographic cruise data accumulated over the past three decades has revealed a heterogeneous distribution of diazotroph species at regional to global scales. However, dynamic fine-scale physical structures likely affect the distribution of diazotrophs at smaller spatiotemporal scales.

Classification and Nomenclature of Metacaspases and Paracaspases: No More Confusion with Caspases.

Metacaspases and paracaspases are proteases that were first identified as containing a caspase-like structural fold (Uren et al., 2000). Like caspases, meta- and paracaspases are multifunctional proteins regulating diverse biological phenomena, such as aging, immunity, proteostasis and programmed cell death.

Metacaspase involvement in programmed cell death of the marine cyanobacterium Trichodesmium.

Metacaspases are cysteine specific proteases implicated in cell-signalling, stress acclimation and programmed cell death (PCD) pathways in plants, fungi, protozoa, bacteria and algae. We investigated metacaspase-like gene expression and biochemical activity in the bloom-forming, N -fixing, marine cyanobacterium Trichodesmium, which undergoes PCD under low iron and high-light stress. We examined these patterns with respect to in-silico analyses of protein domain architectures that revealed a diverse array of regulatory domains within Trichodesmium metacaspases-like (TeMC) proteins.

Iron and phosphorus deprivation induce sociality in the marine bloom-forming cyanobacterium Trichodesmium.

Trichodesmium spp. are diazotrophic cyanobacteria that exist as single filaments (trichomes) and as macroscopic colonies of varying shapes formed by aggregating trichomes. The causes and dynamics of colony formation and disassociation are not yet elucidated.

Benefit from decline: the primary transcriptome of Alteromonas macleodii str. Te101 during Trichodesmium demise.

Interactions between co-existing microorganisms deeply affect the physiology of the involved organisms and, ultimately, the function of the ecosystem as a whole. Copiotrophic Alteromonas are marine gammaproteobacteria that thrive during the late stages of phytoplankton blooms in the marine environment and in laboratory co-cultures with cyanobacteria such as Trichodesmium. The response of this heterotroph to the sometimes rapid and transient changes in nutrient supply when the phototroph crashes is not well understood.

Chasing after Non-cyanobacterial Nitrogen Fixation in Marine Pelagic Environments.

Traditionally, cyanobacterial activity in oceanic photic layers was considered responsible for the marine pelagic dinitrogen (N) fixation. Other potentially N-fixing bacteria and archaea have also been detected in the pelagic water column, however, the activity and importance of these non-cyanobacterial diazotrophs (NCDs) remain poorly constrained. In this perspective we summarize the N fixation rates from recently published studies on photic and aphotic layers that have been attributed to NCD activity via parallel molecular measurements, and discuss the status, challenges, and data gaps in estimating non-cyanobacterial N fixation NCNF in the ocean.

Genome of a giant bacteriophage from a decaying Trichodesmium bloom.

De-novo assembly of a metagenomic dataset obtained from a decaying cyanobacterial Trichodesmium bloom from the New Caledonian lagoon resulted in a complete giant phage genome of 257,908bp, obtained independently with multiple assembly tools. Noteworthy, gammaproteobacteria were an abundant fraction in the sequenced samples. Mapping of the raw reads with 99% accuracy to the giant phage genome resulted in an average coverage of 262X.

The effect of coagulants and antiscalants discharged with seawater desalination brines on coastal microbial communities: A laboratory and in situ study from the southeastern Mediterranean.

Desalination outflows frequently discharge brine containing coagulants and antiscalants (e.g. Iron-hydroxides and polyphosphonates) to the coastal environment.

Microbial metatranscriptomes from the thermally stratified Gulf of Aqaba/Eilat during summer.

The water column in the oligotrophic Gulf of Aqaba/Eilat experiences distinct seasonal cycles with the cooling air and water temperatures of late fall and winter destabilizing the thermocline and forming mixed layer depths reaching 300 to 700m. As air temperatures warm thermal re-stratification results in a stable thermocline throughout the summer which physically separates a photic, nutrient-poor surface layer from an aphotic, nutrient-rich deep layer. Here we present the first metatranscriptome dataset, and its taxonomic assignments, sampled from three depths of the 700m deep Station A in the Gulf of Aqaba during the summer stratification (surface - 10m, deep chlorophyll maximum (DCM) - 85m, deep aphotic zone -500m).

Trimethylated homoserine functions as the major compatible solute in the globally significant oceanic cyanobacterium Trichodesmium.

The oceanic N-fixing cyanobacterium Trichodesmium spp. form extensive surface blooms and contribute significantly to marine carbon and nitrogen cycles in the oligotrophic subtropical and tropical oceans. Trichodesmium grows in salinities from 27 to 43 parts per thousand (ppt), yet its salt acclimation strategy remains enigmatic because the genome of Trichodesmium erythraeum strain IMS101 lacks all genes for the biosynthesis of any known compatible solute.

mdRNA-Seq analysis of marine microbial communities from the northern Red Sea.

Metatranscriptomic differential RNA-Seq (mdRNA-Seq) identifies the suite of active transcriptional start sites at single-nucleotide resolution through enrichment of primary transcript 5' ends. Here we analyzed the microbial community at 45 m depth at Station A in the northern Gulf of Aqaba, Red Sea, during 500 m deep mixing in February 2012 using mdRNA-Seq and a parallel classical RNA-Seq approach. We identified promoters active in situ for five different pico-planktonic genera (the SAR11 clade of Alphaproteobacteria, Synechococcus of Cyanobacteria, Euryarchaeota, Thaumarchaeota, and Micromonas as an example for picoeukaryotic algae), showing the applicability of this approach to highly diverse microbial communities.

Enhanced salinities, as a proxy of seawater desalination discharges, impact coastal microbial communities of the eastern Mediterranean Sea.

Seawater desalination plants increase local coastal salinities by discharging concentrated brine back to the sea with ∼ 50% higher than ambient salinities. The impacts of high salinities on microbial coastal populations of the eastern Mediterranean Sea (EMS) were examined in two mesocosm experiments; first, during the mixed-spring and second, during the stratified-summer periods with average salinity of ∼ 39. Ambient salinities were increased by 5% and 15%.

The primary transcriptome of the marine diazotroph Trichodesmium erythraeum IMS101.

Blooms of the dinitrogen-fixing marine cyanobacterium Trichodesmium considerably contribute to new nitrogen inputs into tropical oceans. Intriguingly, only 60% of the Trichodesmium erythraeum IMS101 genome sequence codes for protein, compared with ~85% in other sequenced cyanobacterial genomes. The extensive non-coding genome fraction suggests space for an unusually high number of unidentified, potentially regulatory non-protein-coding RNAs (ncRNAs).

Trichodesmium’s strategies to alleviate phosphorus limitation in the future acidified oceans.

Global warming may exacerbate inorganic nutrient limitation, including phosphorus (P), in the surface waters of tropical oceans that are home to extensive blooms of the marine diazotrophic cyanobacterium, Trichodesmium. We examined the combined effects of P limitation and pCO(2), forecast under ocean acidification scenarios, on Trichodesmium erythraeum IMS101 cultures. We measured nitrogen acquisition,glutamine synthetase activity, C uptake rates, intracellular Adenosine Triphosphate (ATP) concentration and the pool sizes of related key proteins.

Depth dependent metatranscriptomes of the marine pico-/nanoplanktonic communities in the Gulf of Aqaba/Eilat during seasonal deep mixing.

Metatranscriptomics is a widely used approach to study the gene expression within a whole microbial community. Spatial or temporal differences observed between datasets point to transcriptional responses to changes or alterations in the community's environment. No transcriptomic data has yet been published from the oligotrophic Gulf of Aqaba/Eilat, northern Red Sea.

Dinitrogen fixation in aphotic oxygenated marine environments.

We measured N2 fixation rates from oceanic zones that have traditionally been ignored as sources of biological N2 fixation; the aphotic, fully oxygenated, nitrate (NO(-) 3)-rich, waters of the oligotrophic Levantine Basin (LB) and the Gulf of Aqaba (GA). N2 fixation rates measured from pelagic aphotic waters to depths up to 720 m, during the mixed and stratified periods, ranged from 0.01 nmol N L(-1) d(-1) to 0.

Programmed cell death in the marine cyanobacterium Trichodesmium mediates carbon and nitrogen export.

The extent of carbon (C) and nitrogen (N) export to the deep ocean depends upon the efficacy of the biological pump that transports primary production to depth, thereby preventing its recycling in the upper photic zone. The dinitrogen-fixing (diazotrophic) Trichodesmium spp. contributes significantly to oceanic C and N cycling by forming extensive blooms in nutrient-poor tropical and subtropical regions.

Bioflocculation: chemical free, pre-treatment technology for the desalination industry.

Rapid sand filtration (RSF), proceeded by chemical coagulation and flocculation, is a commonly used, effective pretreatment in the desalination industry. We designed and tested a novel, large pilot-scale, two-stage granular Rapid Bioflocculation Filter (RBF) based on a first-stage Bioflocculator (BF) unit followed by a mixed-media bed filter (MBF). The BF filter bed consisted of an extremely porous volcanic Tuff granular medium which provided an enlarged surface area for microbial development and biofilm proliferation.