Nematocytes, the stinging cells of cnidarians, are most evolutionarily ancient venom apparatus. These nanosyringe-like weaponry systems reach pressures approximately 150 atmospheres before discharging and punching through outer layer prey or predator at accelerations more than 5 million g, making them one fastest biomechanical events known. To gain better understanding function complex, phylum-specific nematocyst organelle, its payload, we compared soluble nematocyst's proteome from sea...

In the oceans and seas, environmental conditions change over multiple temporal spatial scales. Here, we ask what factors affect bacterial community structure across time, depth size fraction during six seasonal cruises (2 years) in ultra-oligotrophic Eastern Mediterranean Sea. The varied most between fractions (free-living (FL) vs. particle-associated), followed by finally season. FL was taxonomically richer more stable than particle-associated (PA) one, which characterized recurrent...

Abstract Marine phytoplankton are responsible for about half of the photosynthesis on Earth. Many mixotrophs, combining with heterotrophic assimilation organic carbon, but relative contribution these two lifestyles is unclear. Here single-cell measurements reveal that Prochlorococcus at base photic zone in Eastern Mediterranean Sea obtain only ~20% carbon required growth by photosynthesis. This supported laboratory-calibrated calculations based photo-physiology parameters and compared situ...

The ability of microorganisms to withstand long periods nutrient starvation is key their survival and success under highly fluctuating conditions that are common in nature. Therefore, one would expect this trait be prevalent among organisms the nutrient-poor open ocean. Here, we show not case for Prochlorococcus , a globally abundant ecologically important marine cyanobacterium. Instead, relies on co-occurring heterotrophic bacteria survive extended phases light starvation. Our results...

Phytoplankton-bacterium interactions are mediated, in part, by phytoplankton-released dissolved organic matter (DOMp). Two factors that shape the bacterial community accompanying phytoplankton (i) producer species, defining initial composition of released DOMp, and (ii) DOMp transformation over time. We added from diatom Skeletonema marinoi cyanobacterium Prochlorococcus marinus MIT9312 to natural communities eastern Mediterranean determined responses a time course 72 h terms cell numbers,...

Phytoplankton growth and death depend on interactions with heterotrophic bacteria, yet the underlying mechanisms remain mostly unclear. We ask whether mathematical models explicitly representing four putative of interaction (overflow metabolism, mixotrophy, exoenzymes ROS detoxification) can recapitulate laboratory co-cultures between Prochlorococcus 8 ranging from synergism to antagonism. Two fundamentally distinct modes emerge models: i) Organic carbon nitrogen recycling through or...

Toxic cyanobacterial blooms are a growing threat to freshwater bodies worldwide. In order for toxic bloom occur, population of cells with the genetic capacity produce toxins must be present together appropriate environmental conditions. this study, we investigated distribution patterns and phylogeny potentially-toxic Microcystis (indicated by presence and/or mcyD mcyA genes). Samples were collected from water column almost sixty across widely differing gradients conditions land use in...

Marine microbial communities vary seasonally and spatially, but these two factors are rarely addressed together. In this study, the temporal spatial patterns of bacterial archaeal community were studied along a coast-to-offshore transect in Eastern Mediterranean Sea (EMS) over six cruises, three seasons 2 consecutive years. Amplicon sequencing 16S rRNA genes transcripts was performed to determine presence activity, respectively. The ultra-oligotrophic status Southeastern reflected...

Marine bacteria rely on phytoplankton exudates as carbon sources (DOCp). Yet, it is unclear to what extent also provide nutrients such phytoplankton-derived N and P (DONp, DOPp). We address these questions by mesocosm exudate addition experiments with spent media from the ubiquitous pico-cyanobacterium Prochlorococcus bacterial communities in contrasting ecosystems Eastern Mediterranean - a coastal an open-ocean, oligotrophic station without on-top additions of inorganic nutrients. Inorganic...

ABSTRACT Heterotrophic marine bacteria utilize and recycle dissolved organic matter (DOM), impacting biogeochemical cycles. It is currently unclear to what extent distinct DOM components can be used by different heterotrophic clades. Here, we ask how a natural microbial community from the Eastern Mediterranean Sea (EMS) responds molecular classes of (peptides, amino acids, sugars, disaccharides, monosaccharides, acids) comprising much biomass living organisms. Bulk bacterial activity...

Sunlight can be directly harvested by photoheterotrophic bacteria to create a pH gradient across the membrane, which then utilized produce ATP. Despite potential importance of this trophic strategy, when and where such organisms are found in seas oceans is poorly described. Here, we describe abundance taxonomy with different strategies (heterotrophs, phototrophs photoheterotrophs) contrasting water masses ultra-oligotrophic eastern Mediterranean Sea. These bodies, an anticyclonic eddy...

Abstract In this study, we test the applicability of Droop/Caperon internal stores model to describe growth and decline globally abundant marine cyanobacterium Prochlorococcus in batch culture as a function external inorganic organic carbon nitrogen. A rigorous parameter fitting exercise, constrained by measured cell density, ammonium concentrations, revealed many different combinations values that provided equally good model‐data fit. Introducing data on C : N ratio from published...

Genome sequencing is rapidly becoming a staple technique in environmental and clinical microbiology, yet computational challenges still remain, leading to many draft genomes which are typically fragmented into contigs. We sequenced completely assembled the genome of marine heterotrophic bacterium, Alteromonas macleodii HOT1A3, compared its full several obtained using different reference-based de-novo methods. In general, assemblies clearly outperformed or hybrid ones, covering>99% genes...

Amplicon sequencing of the 16S rRNA gene is extensively used to characterize bacterial communities, including those living in association with eukaryotic hosts. Deciding which region analyze and selecting appropriate PCR primers remains a major decision when initiating any new microbiome study. Based on detailed literature survey studies focusing cnidarian microbiomes, we compared three commonly targeting different hypervariable regions gene, V1V2, V3V4, V4V5, using jellyfish Rhopilema...

Abstract Every living cell is composed of macromolecules such as proteins, DNA, RNA, and pigments. The ratio between these macromolecular pools depends on the allocation resources within organism to different physiological requirements, in turn affects biogeochemical cycles elements carbon, nitrogen, phosphorus. Here, we present detailed measurements composition Prochlorococcus MIT9312, a representative strain globally abundant marine primary producer, it grows declines due nitrogen...

Abstract Due to their potential impact on ecosystems and biogeochemistry, microbial interactions, such as those between phytoplankton bacteria, have been studied intensively using specific model organisms. Yet, what extent interactions differ closely related organisms, or how these change over time, culture conditions, remains unclear. Here, we characterize the five strains each of two globally abundant marine microorganisms, Prochlorococcus (phototroph) Alteromonas (heterotroph), from first...

Abstract The Eastern Mediterranean Sea (EMS) is a poorly studied ultra-oligotrophic marine environment, dominated by small-size phyto- and bacterioplankton. Here, we describe the dynamics of single annual cycle (2018-19) bacterioplankton (abundances, pigments productivity) in relation to physical chemical conditions photic water column at an offshore EMS site (Station THEMO-2, ∼1,500m depth, 50km offshore). We show that phytoplankton biomass (as chlorophyll a), primary bacterial productivity...

Abstract Heterotrophic marine bacteria utilize and recycle dissolved organic matter (DOM), impacting biogeochemical cycles. It is currently unclear to what extent distinct DOM components can be utilized by different heterotrophic clades. Here, we ask how a natural microbial community from the Eastern Mediterranean Sea responds molecular classes of DOM. These - peptides, amino acids, sugars, disaccharides, monosaccharides acids together comprise much biomass living organisms, released upon...

Metabolomics can be used to study complex mixtures of natural products, or secondary metabolites, for many different purposes. One productive application metabolomics that has emerged in recent years is the guiding direction isolating molecules with structural novelty through analysis untargeted LC-MS/MS data. The metabolomics-driven investigation and bioassay-guided fractionation a biomass assemblage from South China Sea dominated by marine filamentous cyanobacteria, cf. Neolyngbya sp., led...

Abstract Marine phytoplankton are responsible for about half of the photosynthesis on Earth. Many mixotrophs, combining with heterotrophic assimilation organic carbon but relative contribution these two sources is not well quantified. Here, single-cell measurements reveal that Prochlorococcus at base photic zone in Eastern Mediterranean Sea obtaining only ~20% required growth by photosynthesis. Consistently, laboratory-calibrated evaluations indicate fixation systematically too low to...

Abstract Every living cell is composed of macromolecules such as proteins, DNA, RNA and pigments. The ratio between these macromolecular pools depends on the allocation resources within organism to different physiological requirements, in turn affects biogeochemical cycles elements carbon, nitrogen phosphorus. Here, we present detailed measurements composition Prochlorococcus MIT9312, a representative strain globally abundant marine primary producer, it grows declines due starvation...

Abstract Marine microbial communities vary seasonally and spatially, but these two factors are rarely addressed together. We studied temporal spatial patterns of the community structure activity along a coast to offshore transect from Israeli Eastern Mediterranean Sea (EMS) over six cruises, in three seasons consecutive years. The ultra-oligotrophic status South was reflected composition that dominated by oligotrophic groups such as SAR11 throughout year, even at most coastal station...