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Three ceramides with intriguing structural features, bathymodiolamides C (1), D (2), and E (3). were isolated from the deep-sea hydrothermal vent invertebrate mussel Bathymodiolus azoricus that inhabits vent environments along the Mid-Atlantic Ridge. The molecular structures of these compounds were elucidated using a combination of Nuclear Magnetic Resonance spectroscopy, mass spectrometry, and chemical degradation. Biological activities were assessed by Lactate Dehydrogenase assay for necrosis induction and the patented ApopSereen cell-based screen for apoptosis-induction and potential anticancer activity. This represents a second report of ceramide natural products from B. azoricus. KEY WORDS: Ceramide, necrosis inducer, anticancer agent, marine biotechnology, marine hydrothermal vent mussel, Bathymodiolus azoricus, INTRODUCTION Cell death regulations have been arranged based on morphological criteria into three categories (Okada & Mak 2004): apoptosis, autophagy, and necrosis. Apoptosis or type I cell death (the most [...]

In March 2024, tag team operations between a deep-sea robot and a human-occupied submersible led to the discovery of new hydrothermal vent sites more than a mile below the ocean […]

$5M National Science Foundation Digital Twin Network for the coral reef blue economy $2.5M Windward Foundation Ocean alkalinity enhancement trial on the U.S. Northeast continental shelf $2M Simons Foundation Biochemical [...]

Abstract Jambu (Acmella oleracea (L.) R.K. Jansen) is a neglected plant native to the Amazon Biome. Although it is very consumed in the north of Brazil, little is known about its chemical and nutritional composition. Thus, this study aimed to characterize jambu and to evaluate the effects of the boiling process on its chemical composition. The proximate composition, minerals, total amino acids, fatty acids levels, and phytosterols were determined. In comparison with conventional vegetables jambu presented higher levels of protein (24.01%), ash (10.92%), total fiber (62.61%) some mineral such as Ca (2551.56 mg/100 g), Mg (734 mg/100 g) and Cu (2.09 mg/100 g), and amino acids such as asparagine (32.01 mg/g), glutamic acid (28.26 mg/g), valine (14.55 mg/g) and isoleucine (14.19 mg/g). A significant reduction was observed in carbohydrates, total dietary fibers, minerals, unsaturated fatty acids, and in some amino acid levels after the boiling process, with an increase in ash content, protein, and saturated fatty acids in the heat-treated jambu. Lipids, phytosterols, and some amino acid levels were not significantly affected by the hydrothermal process. Thus, this study has shown that raw and processed jambu may be good alternatives for conventional vegetables, even with nutrients losses during boiling. Graphical abstract Unlabelled Image Highlights • The influence of the boiling process in jambu nutritional content was evaluated. • Protein, ash, Na, and some amino acid and fatty acid levels increased after heating. • Nutrients content are higher or similar in jambu than in conventional vegetables. • Raw and processed jambu can be used to improve the food security. [ABSTRACT FROM AUTHOR]

Highlights • Germination rate and germination percentage of R. raetam seeds were significantly influenced by ψ , T and their interactions (P < 0.01). • Cardinal Ts were 4.2°C for T b , 17°C for T o and 30°C for T c at 0 MPa. The T d (the T at which ψ b(50) starts to change) was estimated to be 10°C. • By increasing Ts to T o , hydrotime constant (θH) decreased nonlinearly and then stabilized to 30 MPa °C h at Ts ranging from 15 to 30°C. • The HTT model can accurately describe the time course of germination across all Ts and ψ s for this plant (R2 = 0.90). • Estimated parameters using HTT model were 388.6 MPa °C h for θ HTT , –0.913 MPa for ψ b(50) and 0.047 MPa °C h for the k T (the slope of ψ b(50) x T ≥ T d). Abstract Retama raetam (Forssk Webb; Fabaceae) is a xerophytic shrub that is distributed from northern to southern Tunisia and which is of interest for medical use and for revegetation. To quantify seed germination responses of R. raetam to temperature (T) and water potential (ψ), and to determine cardinal Ts, a hydrothermal time model (HTT) was used. The experiment was conducted at six constant Ts (5, 10, 15, 20, 25, and 30 °C) at each of the following ψ s (0, –0.3, –0.7 and −1 MPa; provided by PEG 6000). Results showed that germination rate (GR) and germination percentage (GP) were significantly influenced by ψ , T and their interactions (P < 0.01). Cardinal Ts for R. raetam was 4.2 °C for T b (the base T), 17 °C for T o (the optimum T) and 30 °C for T c (the ceiling T) in the control condition (0 MPa). The T d (the T at which ψ b(50) starts to change) was estimated to be 10 °C. By increasing T to T o , hydrotime constant (θ H) decreased nonlinearly and then stabilized to 30 MPa °C h at Ts ranging from 15 to 30 °C. The study showed that when the HTT model is applied, it can accurately describe the time course of germination across all Ts and ψ s for this plant (R2 = 0.90). Moreover, estimated parameters using HTT model were 388.6 MPa °C h for the hydrothermal time constant (θ HTT), –0.913 MPa for the base water potential (ψ b(50)) and 0.047 MPa °C h for the k T (the slope of the relationship between ψ b(50) and T ≥ T d). The parameters presented in this study can easily be used in R. raetam SG simulation models for characterizing the physiological status of R. raetam seed populations and also for predicting germination time courses of this plant under different environmental conditions. [ABSTRACT FROM AUTHOR]

Microbes living around hydrothermal vents have developed lots of enzymes with specific characteristics that allow them to thrive in the environment. Extracellular enzyme leucine aminopeptidases (LAPs) are all metallopeptidases that catalyze the hydrolysis of leucine residues from N-terminal residues from peptides and proteins. Genomic analysis of Pseudoalteromonas telluritireducens DSM 16098, a strain of deep-sea bacteria isolated from hydrothermal vents fluid, revealed the presence of an LAP gene (designated as PtLAP). The open reading frame of PtLAP encodes a protein of 614 amino acids (GenBank accession no. KY429939 ), consisting of a signal peptide, a peptidase_M1 domain and a leuk-A4-hydro_C domain. The putative substrate binding site GGMEN, zinc-binding motif HEXXHX 18 E and the catalytic residues involved in aminopeptidase activity are all conserved, indicating PtLAP is a member of M1 leucine aminopeptidases. The recombinant PtLAP expressed in Escherichia coli Transetta (DE3) (designated as rPtLAP) exhibits a significant LAP activity to hydrolyze L -leucine 7-amido-4-methylcoumarin (MAC-L). The optimal activity of rPtLAP is observed at pH 7.2 and 28 °C with half-saturation coefficient (K m ) of 44.56 ± 5.09 μmol L −1 . rPtLAP activity is relatively stable at 30–40 °C and exhibits a relatively wide pH range (6.0–12.5) with the maximal activity ranging at pH 7.2–8.0. It can be inhibited by EDTA, protease inhibitors and some metal ions including Cu 2+ , Zn 2+ and Cd 2+ , but is relatively tolerant to Mn 2+ which is enriched in hydrothermal vent fluids. Furthermore, rPtLAP can significantly promote the proliferation of tumor cells, including the cell lines HCT116, BEL-7402 and Hela, while displays no effect on that of normal cell 3T3. These results together suggest that the extracellular enzyme PtLAP executes the degradation of organic matters, contributes to the adaptive survival of microbe in deep-sea environment and may play important roles in marine biogeochemical cycles. [ABSTRACT FROM AUTHOR]

Herein, the rheological properties of microalgae slurries ( Chlorella pyrenoidosa ) under different mass fractions and temperatures (293–373 K) were reported, which can significantly affect the energy requirement of hydrothermal pretreatment process and hence the performance of fermentation processes. The experiment results showed that the microalgae slurry had a shear-thinning phenomenon, suggesting that microalgae slurry is a non-Newtonian fluid. For the first time, the phenomenon of variable flow behavior index under varying shear rates was discovered. In addition, the viscosity and yield stress of the microalgae slurries decreased from 293 to 343 K; above 343 K, they increased with the temperature. Scanning electron microscopy analyses showed that the surface of the microalgae cells became rougher when the temperature increased from 343 to 373 K. Finally, the equations of the viscosity of the microalgae slurry, based on the temperatures and shear rates, were obtained. [ABSTRACT FROM AUTHOR]

Summary: Viruses represent a driving force in the evolution of microorganisms including those thriving in extreme environments. However, our knowledge of the viral diversity associated to microorganisms inhabiting the deep‐sea hydrothermal vents remains limited. The phylum of Thermotogae, including thermophilic bacteria, is well represented in this environment. Only one virus was described in this phylum, MPV1 carried by Marinitoga piezophila. In this study, we report on the functional and genomic characterization of two new bacterioviruses that infect bacteria from the Marinitoga genus. Marinitoga camini virus 1 and 2 (MCV1 and MCV2) are temperate siphoviruses with a linear dsDNA genome of 53.4 kb and 50.5 kb respectively. Here, we present a comparative genomic analysis of the MCV1 and MCV2 viral genomes with that of MPV1. The results indicate that even if the host strains come from geographically distant sites, their genomes share numerous similarities. Interestingly, heavy metals did not induce viral production, instead the host of MCV1 produced membrane vesicles. This study highlights interaction of mobile genetic elements (MGE) with their hosts and the importance of including hosts‐MGEs' relationships in ecological studies. [ABSTRACT FROM AUTHOR]

Summary: At deep‐sea hydrothermal vents, microbial communities thrive across geochemical gradients above, at, and below the seafloor. In this study, we determined the gene content and transcription patterns of microbial communities and specific populations to understand the taxonomy and metabolism both spatially and temporally across geochemically different diffuse fluid hydrothermal vents. Vent fluids were examined via metagenomic, metatranscriptomic, genomic binning, and geochemical analyses from Axial Seamount, an active submarine volcano on the Juan de Fuca Ridge in the NE Pacific Ocean, from 2013 to 2015 at three different vents: Anemone, Marker 33, and Marker 113. Results showed that individual vent sites maintained microbial communities and specific populations over time, but with spatially distinct taxonomic, metabolic potential, and gene transcription profiles. The geochemistry and physical structure of each vent both played important roles in shaping the dominant organisms and metabolisms present at each site. Genomic binning identified key populations of SUP05, Aquificales and methanogenic archaea carrying out important transformations of carbon, sulfur, hydrogen, and nitrogen, with groups that appear unique to individual sites. This work highlights the connection between microbial metabolic processes, fluid chemistry, and microbial population dynamics at and below the seafloor and increases understanding of the role of hydrothermal vent microbial communities in deep ocean biogeochemical cycles. [ABSTRACT FROM AUTHOR]

Abstract: The Yellowstone National Park ecosystem is a product of dynamic earth system processes, which have been of interest to scientists and the public since the park's discovery. Here, we outline the history of two successive generations of scientific collaboration in Yellowstone National Park. Early collaboration was spurred by the discovery of an unknown diatom species found in Yellowstone Lake. This prompted the first coring project in 1992 that described the morphological evolution of that species and the paleoenvironmental conditions during which it evolved. About twenty years later, the group was brought together again, with the addition of early career scientists, for a coring project focused on hydrothermal activity in the Yellowstone Lake basin. We discuss the ongoing research and analyses of core material, and conclude with the benefits of working in multigenerational interdisciplinary research groups. [ABSTRACT FROM AUTHOR]

This study develops a model to estimate the spatiotemporal distribution of stream algae on a basin scale by integrating an existing periphyton model into a distributed hydrothermal model to calculate the daily periphyton biomass throughout the Natori River basin. The influence of inorganic phosphorus on periphyton growth is incorporated into the periphyton model. The inorganic phosphorus concentration is simulated using the distributed pollute model depending on land use data to determine the phosphorus load. The model had a root mean square error (RMSE) = 14.1 mg/m 2 for periphyton biomass in the entire basin. This model shows that periphyton biomass tends to increase in the summer season with high water temperature and to decrease in the spring season with high discharge. This model can be applied to understand large spatial and temporal areas of the environment in a temperate catchment. [ABSTRACT FROM AUTHOR]

The environments around deep-sea hydrothermal vents are very harsh conditions for organisms due to the possibility of exposure to highly toxic compounds and extremely hot venting there. Despite such extreme environments, some indigenous species have thrived there. Alvinellid worms (Annelida) are among the organisms best adapted to high-temperature and oxidatively stressful venting regions. Although intensive studies of the adaptation of these worms to the environments of hydrothermal vents have been made, little is known about the worms’ sensory adaptation to the severe chemical conditions there. To examine the sensitivity of the vent-endemic worm Paralvinella hessleri to low pH and oxidative stress, we determined the concentration of acetic acid and hydrogen peroxide that induced avoidance behavior of this worm, and compared these concentrations to those obtained for related species inhabiting intertidal zones, Thelepus sp. The concentrations of the chemicals that induced avoidance behavior of P. hessleri were 10–100 times lower than those for Thelepus sp. To identify the receptors for these chemicals, chemical avoidance tests were performed with the addition of ruthenium red, a blocker of transient receptor potential (TRP) channels. This treatment suppressed the chemical avoidance behavior of P. hessleri, which suggests that TRP channels are involved in the chemical avoidance behavior of this species. Our results revealed for the first time hypersensitive detection systems for acid and for oxidative stress in the vent-endemic worm P. hessleri, possibly mediated by TRP channels, suggesting that such sensory systems may have facilitated the adaptation of this organism to harsh vent environments. [ABSTRACT FROM AUTHOR]

The assessment and comparison of food webs across various hydrothermal vent sites can enhance our understanding of ecological processes involved in the structure and function of biodiversity. The Menez Gwen, Lucky Strike and Rainbow vent fields are located on the Azores triple junction of the Mid-Atlantic Ridge. These fields have distinct depths (from 850 to 2320 m) and geological contexts (basaltic and ultramafic), but share similar faunal assemblages defined by the presence of foundation species that include Bathymodiolus azoricus, alvinocarid shrimp and gastropods. We compared the food webs of 13 faunal assemblages at these three sites using carbon and nitrogen stable isotope analyses (SIA). Results showed that photosynthesis-derived organic matter is a negligible basal source for vent food webs, at all depths. The contribution of methanotrophy versus autotrophy based on Calvin-Benson-Bassham (CBB) or reductive tricarboxylic acid (rTCA) cycles varied between and within vent fields according to the concentrations of reduced compounds (e.g. CH 4 , H 2 S). Species that were common to vent fields showed high trophic flexibility, suggesting weak trophic links to the metabolism of chemosynthetic primary producers. At the community level, a comparison of SIA-derived metrics between mussel assemblages from two vent fields (Menez Gwen & Lucky Strike) showed that the functional structure of food webs was highly similar in terms of basal niche diversification, functional specialization and redundancy. Coupling SIA to functional trait approaches included more variability within the analyses, but the functional structures were still highly comparable. These results suggest that despite variable environmental conditions (physico-chemical factors and basal sources) and faunal community structure, functional complexity remained relatively constant among mussel assemblages. This functional similarity may be favoured by the propensity of species to adapt to fluid variations and practise trophic flexibility. Furthermore, the different pools of species at vent fields may play similar functions in the community such as the change in composition does not affect the overall functional structure. Finally, the absence of a relationship between the functional structure and taxonomic diversity as well as the high overlap between species’ isotopic niches within communities indicates that co-occuring species may have redundant functions. Therefore, the addition of species within in a functional group does not necessarily lead to more complexity. Overall, this study highlights the complexity of food webs within chemosynthetic communities and emphasizes the need to better characterize species’ ecological niches and biotic interactions. [ABSTRACT FROM AUTHOR]

Deep-sea hydrothermal sediment is known to support remarkably diverse microbial consortia. In deep sea environments, fungal communities remain less studied despite their known taxonomic and functional diversity. High-throughput sequencing methods have augmented our capacity to assess eukaryotic diversity and their functions in microbial ecology. Here we provide the first description of the fungal community diversity found in deep sea sediments collected at the Southwest Indian Ridge (SWIR) using culture-dependent and high-throughput sequencing approaches. A total of 138 fungal isolates were cultured from seven different sediment samples using various nutrient media, and these isolates were identified to 14 fungal taxa, including 11 Ascomycota taxa (7 genera) and 3 Basidiomycota taxa (2 genera) based on internal transcribed spacers (ITS1, ITS2 and 5.8S) of rDNA. Using illumina HiSeq sequencing, a total of 757,467 fungal ITS2 tags were recovered from the samples and clustered into 723 operational taxonomic units (OTUs) belonging to 79 taxa (Ascomycota and Basidiomycota contributed to 99% of all samples) based on 97% sequence similarity. Results from both approaches suggest that there is a high fungal diversity in the deep-sea sediments collected in the SWIR and fungal communities were shown to be slightly different by location, although all were collected from adjacent sites at the SWIR. This study provides baseline data of the fungal diversity and biogeography, and a glimpse to the microbial ecology associated with the deep-sea sediments of the hydrothermal vent system of the Southwest Indian Ridge. [ABSTRACT FROM AUTHOR]

Irradiated ice-covered ocean worlds with rocky mafic mantles may provide the conditions needed to drive the emergence and maintenance of life. Alkaline hydrothermal springs-relieving the geophysical, thermal, and chemical disequilibria between oceans and tidally stressed crusts-could generate inorganic barriers to the otherwise uncontrolled and kinetically disfavored oxidation of hydrothermal hydrogen and methane. Ionic gradients imposed across these inorganic barriers, comprising iron oxyhydroxides and sulfides, could drive the hydrogenation of carbon dioxide and the oxidation of methane through thermodynamically favorable metabolic pathways leading to early life-forms. In such chemostatic environments, fuels may eventually outweigh oxidants. Ice-covered oceans are primarily heated from below, creating convection that could transport putative microbial cells and cellular cooperatives upward to congregate beneath an ice shell, potentially giving rise to a highly focused shallow biosphere. It is here where electron acceptors, ultimately derived from the irradiated surface, could be delivered to such life-forms through exchange with the icy surface. Such zones would act as 'electron disposal units' for the biosphere, and occupants might be transferred toward the surface by buoyant diapirs and even entrained into plumes. Key Words: Biofilms-Europa-Extraterrestrial life-Hydrothermal systems. Astrobiology 17, 1265-1273. [ABSTRACT FROM AUTHOR]

Hydrothermal vent systems are inhabited by dense benthic communities adapted to extreme conditions such as high temperature, hydrogen sulphide (H 2 S) and elevated fluxes of metals. In the present work, a wide range of trace elements (Ag, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Se, V and Zn) were measured in tissues of three tube dwelling annelids, Alvinella pompejana , Alvinella caudata and Riftia pachyptila , which colonize distinct habitats of the East Pacific Rise (EPR) at 2500 m depth. Metals concentrations in alvinellids were often 2–4 orders of magnitude higher than those commonly found in marine organisms, while much lower values were observed in the vestimentiferan polychaete. Mobility of trace elements was further characterized in tissues of A. pompejana where metals appeared mostly in insoluble forms, i.e. associated with hydrated oxides and sulphides. Arsenic was mainly present in a weakly insoluble form and with concentrations in the branchial tentacles of alvinellids, approximately 5–15 fold higher than those measured in the thorax. Chemical speciation of this element in tissues of the three polychaete species revealed a major contribution of methylated arsenic compounds, like dimethylarsinate (DMA) and, to a lower extent, monomethylarsonate (MMA) and trimethylarsine oxide (TMAO). Although the biotransformation of inorganic arsenic might represent a detoxification mechanism in polychaetes from hydrothermal vents, the elevated levels of methylated forms of arsenic in branchial tissues also suggest an ecological role of this element as an antipredatory strategy for more vulnerable tissues toward generalist consumers. [ABSTRACT FROM AUTHOR]