A unique subseafloor microbiosphere in the Mariana Trench driven by episodic sedimentation.

Hadal trenches are characterized by enhanced and infrequent high-rate episodic sedimentation events that likely introduce not only labile organic carbon and key nutrients but also new microbes that significantly alter the subseafloor microbiosphere. Currently, the role of high-rate episodic sedimentation in controlling the composition of the hadal subseafloor microbiosphere is unknown. Here, analyses of carbon isotope composition in a ~ 750 cm long sediment core from the Challenger Deep revealed noncontinuous deposition, with anomalous 14C ages likely caused by seismically driven mass transport and the funneling effect of trench geomorphology. Microbial community composition and diverse enzyme activities in the upper ~ 27 cm differed from those at lower depths, probably due to sudden sediment deposition and differences in redox condition and organic matter availability. At lower depths, microbial population numbers, and composition remained relatively constant, except at some discrete depths with altered enzyme activity and microbial phyla abundance, possibly due to additional sudden sedimentation events of different magnitude. Evidence is provided of a unique role for high-rate episodic sedimentation events in controlling the subsurface microbiosphere in Earth's deepest ocean floor and highlight the need to perform thorough analysis over a large depth range to characterize hadal benthic populations. Such depositional processes are likely crucial in shaping deep-water geochemical environments and thereby the deep subseafloor biosphere. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-023-00212-y.

Deciphering Microbial Communities and Distinct Metabolic Pathways in the Tangyin Hydrothermal Fields of Okinawa Trough through Metagenomic and Genomic Analyses.

Deep-sea hydrothermal vents have been extensively explored around the globe in the past decades, and the diversity of microbial communities and their ecological functions related to hydrothermal vents have become hotspots in the study of microbial biogeochemistry. However, knowledge of dominant microbial communities and their unique metabolic characteristics adapting to hydrothermal vents is still limited. In our study, the sediment sample near the Tangyin hydrothermal vent in the southern part of the Okinawa Trough was collected, and the most abundant phyla are Proteobacteria and Desulfobacterota based on the 16S rRNA genes and metagenome sequencing. Metagenomic analysis revealed that methane metabolism, sulfur reduction, and Fe2+ uptake were abundantly distributed in hydrothermal sediment. In addition, most of the metagenomic assembly genomes (MAGs), belonging to Chloroflexota, Desulfobacterota, and Gammaproteobacteria, were found to be involved in methanogenesis, sulfur oxidation/reduction, and ferrous/ferric iron metabolisms. Among these MAGs, the two representative groups (Bathyarchaeia and Thioglobaceae) also showed distinct metabolic characteristics related to carbon, sulfur, and iron to adapt to hydrothermal environments. Our results reveal the dominant microbial populations and their metabolic features in the sediment near the Tangyin hydrothermal fields, providing a better understanding of microbial survival strategies in the extreme environment.

The Development of a Novel Fiber-2 Subunit Vaccine against Fowl Adenovirus Serotype 4 Formulated with Oil Adjuvants.

Hepatitis-hydropericardium syndrome (HHS), caused by fowl adenovirus serotype 4 (FAdV-4), has been widely spread across China, resulting in great financial losses in the poultry industry. Therefore, efficient vaccines against this disease urgently need to be developed. In our study, the fiber-2 and penton base proteins derived from the FAdV-4 JS strain were expressed in a prokaryotic system (E. coli) in a soluble form. Then, the efficacy of the two recombinant proteins formulated with cheap and widely used adjuvants (Marcol™ 52 white oil) were respectively tested, and the minimum immune doses and safety of the above proteins were also determined. It was indicated that the fiber-2 (20 µg/bird, 200 µg/bird) and penton base (200 µg/bird) could provide complete protection against the highly pathogenic FAdV-4 and suppress its replication and shedding. Unfortunately, only the fiber-2 protein could induce complete protection (10/10) at a low dose (10 µg/bird). In addition, we confirmed that the fiber-2 subunit vaccine formulated with oil adjuvants was safe for vaccinated chickens. Conclusively, all of our results suggest that we successfully prepared an efficient and cheap fiber-2 subunit vaccine with few side effects.

Environmental heterogeneity of cold seep by biological trait analysis of marine nematodes at Site F cold seep in South China Sea.

Cold seeps provide high environmental heterogeneity for marine benthos. Site F is one of the active cold seeps in the South China Sea. In this study, free-living marine nematode communities were investigated at Site F and the adjacent deep-sea area. A total of 67 genera and 32 families were identified. The mean density at cold seep sites ranged from 13.6 to 181.8 ind./10 cm2, and that at the adjacent deep-sea sites ranged from 36.9 to 301.4 ind./10 cm2. At cold seep sites, the most dominant nematode genera were Desmoscolex, Pierrickia, Sabatieria, Halalaimus, and Dorylaimopsis while at deep-sea sites, the most dominant genera were Retrotheristus, Thalassomonhystera, Desmoscolex, Cobbia, and Halalaimus. Deposit feeders of nematodes were dominant at all sites. Results of biological trait analysis showed that there was high environmental heterogeneity for nematodes at Site F. Water depth, sediment organic matter content, and sand proportion had important influences on nematode communities.

Methylation of TTC4 interaction with HSP70 inhibits pyroptosis in macrophages of sepsis-induced lung injury by NLRP3 inflammation.

Acute lung injury (ALI) is an acute infectious diseases caused by a variety of factors. The function of TTC4 in sepsis-induced lung injury remains largely unknown. This study aimed to explore the critical role of TTC4 in sepsis-induced lung injury. Mice anaesthetized using pentobarbital sodium and subjected to cecal ligation and puncture (CLP) surgery. TTC4 expression levels in patients with sepsis-induced lung injury were down-regulated. The inhibition of TTC4 gene promoted lung injury in mice model of sepsis. TTC4 gene improved inflammation in vitro model and mice model. TTC4 gene reduced pyroptosis in macrophages of sepsis-induced lung injury by the inhibition of mitochondrial damage. TTC4 gene induced HSP70 expression to reduce NLRP3-induced pyroptosis in macrophages. TTC4 protein interlinked HSP70 protein. The activation of HSP70 reduced the effects of sh-TTC4 in model of sepsis-induced lung injury through mitochondrial damage. m6A-forming enzyme METTL3 reduced TTC4 stability. Our study suggests the m6A forming enzyme METTL3 control TTC4 reduced inflammation and pyroptosis in model of sepsis-induced lung injury through inhibition of mitochondrial damage by HSP70/ROS/NLRP3 signaling pathway, TTC4 gene as an represents a potential therapeutic strategy for the treatment of sepsis-induced lung injury.

Hot Deformation Behavior and Processing Maps of 26CrMo7S Steel Used in Oil Exploration.

The hot deformation behavior and flow stress characteristics of experimental 26CrMo7S steel were analyzed using a thermal simulator under a range of conditions, including a strain rate range of 0.01~10 s-1, a temperature range of 850~1250 °C, and a maximum deformation amount of 70%. The Arrhenius constitutive model was built for the corresponding conditions, and the model's accuracy was verified through error analysis. Additionally, hot processing maps were constructed to analyze the processing zone of the steel under different hot deformation conditions. Finally, the microstructure of the processing zones was observed and verified using the electron backscattered diffraction (EBSD). The results indicate that the interaction of work hardening and dynamic softening influences the hot deformation behavior of 26CrMo7S steel. The Arrhenius constitutive equation with a value of the correlation coefficient (r = 0.99523) accurately predicts the flow behavior of 26CrMo7S steel under different strains. The optimal processing zone obtained with the hot processing maps is within a deformation range of 1010~1190 °C and a strain rate range of 0.01~10-1.5 s-1, and the obtained microstructure is in good agreement with the analysis results.

Phylogenetically and metabolically diverse autotrophs in the world's deepest blue hole.

The world's deepest yongle blue hole (YBH) is characterized by sharp dissolved oxygen (DO) gradients, and considerably low-organic-carbon and high-inorganic-carbon concentrations that may support active autotrophic communities. To understand metabolic strategies of autotrophic communities for obtaining carbon and energy spanning redox gradients, we presented finer characterizations of microbial community, metagenome and metagenome-assembled genomes (MAGs) in the YBH possessing oxic, hypoxic, essentially anoxic and completely anoxic zones vertically. Firstly, the YBH microbial composition and function shifted across the four zones, linking to different biogeochemical processes. The recovery of high-quality MAGs belonging to various uncultivated lineages reflected high novelty of the YBH microbiome. Secondly, carbon fixation processes and associated energy metabolisms varied with the vertical zones. The Calvin-Benson-Bassham (CBB) cycle was ubiquitous but differed in affiliated taxa at different zones. Various carbon fixation pathways were found in the hypoxic and essentially anoxic zones, including the 3-hyroxypropionate/4-hydroxybutyrate (3HP/4HB) cycle affiliated to Nitrososphaeria, and Wood-Ljungdahl (WL) pathway affiliated to Planctomycetes, with sulfur oxidation and dissimilatory nitrate reduction as primary energy-conserving pathways. The completely anoxic zone harbored diverse taxa (Dehalococcoidales, Desulfobacterales and Desulfatiglandales) utilizing the WL pathway coupled with versatile energy-conserving pathways via sulfate reduction, fermentation, CO oxidation and hydrogen metabolism. Finally, most of the WL-pathway containing taxa displayed a mixotrophic lifestyle corresponding to flexible carbon acquisition strategies. Our result showed a vertical transition of microbial lifestyle from photo-autotrophy, chemoautotrophy to mixotrophy in the YBH, enabling a better understanding of carbon fixation processes and associated biogeochemical impacts with different oxygen availability.

Distinct coral environments shape the dynamic of planktonic Vibrio spp.

BACKGROUND: Coral reefs are one of the most biodiverse and productive ecosystems, providing habitat for a vast of species. Reef-building scleractinian corals with a symbiotic microbiome, including bacteria, archaea, viruses and eukaryotic microbes, are referred to coral holobionts. Among them, coral diseases, mainly caused by Vibrio spp., have significantly contributed to the loss of coral cover and diversity. Habitat filtering across the globe has led to a variety structure of marine bacterial communities. Coral species, quantity and characteristics are significant differences between the Xisha Islands and Daya Bay (Guangdong Province). Thus, the Vibrio communities may be distinct between coral rich and poor areas. RESULTS: Through comparison of Vibrio dynamics between coral-rich (Xisha Islands) and coral-poor (Daya Bay) locations, we uncovered differences in Vibrio abundance, diversity, community composition and assembly mechanisms associated with corals. The higher abundance of Vibrio in coral rich areas may indicate a strong interaction between vibrios and corals. V. campbellii, Paraphotobacterium marinum and V. caribbeanicus were widely distributed in both coral rich and poor areas, likely indicating weak species specificity in the coral-stimulated growth of Vibrio. Random-forest prediction revealed Vibrio species and Photobacterium species as potential microbial indicators in the coral rich and coral poor areas, respectively. Ecological drift rather than selection governed the Vibrio community assembly in the Xisha Islands. Comparatively, homogenizing selection was more important for the Daya Bay community, which may reflect a role of habitat filtration. CONCLUSION: This study revealed the different distribution pattern and assembly mechanism of Vibrio spp. between coral rich and poor areas, providing the background data for the research of Vibrio community in coral reef areas and may help the protection of coral reef at the biological level. The main reasons for the difference were different number and species of corals, environmental (e.g., temperature) and spatial factors. It reflected the strong interaction between Vibrio and corals, and provided a new perspective for the investigation of Vibrio in coral reef ecosystem.

Genistein upregulates AHR to protect against environmental toxin-induced NASH by inhibiting NLRP3 inflammasome activation and reconstructing antioxidant defense mechanisms.

We have previously proven that the environmental toxin could accelerate the development and progression of nonalcoholic steatohepatitis (NASH). However, the underlying mechanism associated with such excessive inflammation hasn't been fully illustrated. Although Genistein has been well accepted for its capability in anti-inflammation and anti-oxidation, its effect in ameliorating contaminants-induced NASH still needs to be identified. In this study, using chickens and primary chicken hepatocytes as models, we found that NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome were over-activated in bromoacetic acid (BAA, one of the typical environmental toxins)-induced NASH, characterized by the infiltration of inflammatory cell, and the increase of NLRP3, Caspase-1 p20, and cytokines (IL-1ß, IL-18) expressions. Interestingly, genistein treatment could recover these changes, with the signs of restored activities of anti-oxidases, decreased expressions of NLRP3 inflammasome components, and increased levels of elements in phase I metabolic system. The detailed mechanism was that, via up-regulating aryl hydrocarbon receptor (AHR), genistein lifted mRNA levels of Cyp1-related genes to reconstruct cytochrome P450 (CYP450) systems, and the raised AHR negatively regulated NLRP3 inflammasome activity to relieve inflammation. More important, the interaction and co-localization between AHR and NLRP3 was first proved, and genistein could promote the levels of AHR that interacted with NLRP3, which thereafter blocked the activation of NLRP3 inflammasome. Conclusively, in this research, we confirmed the AHR-dependent protective role of genistein in environmental toxin-linked NASH, which shed light on the potential precautions for contaminants-induced NASH.

A moderately thermophilic origin of a novel family of marine group II euryarchaeota from deep ocean.

Marine group II (MGII) is the most abundant planktonic heterotrophic archaea in the ocean. The evolutionary history of MGII archaea is elusive. In this study, 13 new MGII metagenome-assembled genomes were recovered from surface to the hadal zone in Challenger Deep of the Mariana Trench; four of them from the deep ocean represent a novel group. The optimal growth temperature (OGT) of the common ancestor of MGII has been estimated to be at about 60°C and OGTs of MGIIc, MGIIb, and MGIIa at 47°C-50ºC, 37°C-44ºC, and 30°C-37ºC, respectively, suggesting the adaptation of these species to different temperatures during evolution. The estimated OGT range of MGIIc was supported by experimental measurements of cloned ß-galactosidase that showed optimal enzyme activity around 50°C. These results indicate that MGIIc may have originated from a common ancestor that lived in warm or even hot marine environment, such as hydrothermal vents.

Deep-sea Bacteroidetes from the Mariana Trench specialize in hemicellulose and pectin degradation typically associated with terrestrial systems.

BACKGROUND: Hadal trenches (>6000 m) are the deepest oceanic regions on Earth and depocenters for organic materials. However, how these enigmatic microbial ecosystems are fueled is largely unknown, particularly the proportional importance of complex polysaccharides introduced through deposition from the photic surface waters above. In surface waters, Bacteroidetes are keystone taxa for the cycling of various algal-derived polysaccharides and the flux of carbon through the photic zone. However, their role in the hadal microbial loop is almost unknown. RESULTS: Here, culture-dependent and culture-independent methods were used to study the potential of Bacteroidetes to catabolize diverse polysaccharides in Mariana Trench waters. Compared to surface waters, the bathypelagic (1000-4000 m) and hadal (6000-10,500 m) waters harbored distinct Bacteroidetes communities, with Mesoflavibacter being enriched at ≥ 4000 m and Bacteroides and Provotella being enriched at 10,400-10,500 m. Moreover, these deep-sea communities possessed distinct gene pools encoding for carbohydrate active enzymes (CAZymes), suggesting different polysaccharide sources are utilised in these two zones. Compared to surface counterparts, deep-sea Bacteroidetes showed significant enrichment of CAZyme genes frequently organized into polysaccharide utilization loci (PULs) targeting algal/plant cell wall polysaccharides (i.e., hemicellulose and pectin), that were previously considered an ecological trait associated with terrestrial Bacteroidetes only. Using a hadal Mesoflavibacter isolate (MTRN7), functional validation of this unique genetic potential was demonstrated. MTRN7 could utilize pectic arabinans, typically associated with land plants and phototrophic algae, as the carbon source under simulated deep-sea conditions. Interestingly, a PUL we demonstrate is likely horizontally acquired from coastal/land Bacteroidetes was activated during growth on arabinan and experimentally shown to encode enzymes that hydrolyze arabinan at depth. CONCLUSIONS: Our study implies that hadal Bacteroidetes exploit polysaccharides poorly utilized by surface populations via an expanded CAZyme gene pool. We propose that sinking cell wall debris produced in the photic zone can serve as an important carbon source for hadal heterotrophs and play a role in shaping their communities and metabolism. Video Abstract.

G protein-coupled estrogen receptor activation by bisphenol-A disrupts lipid metabolism and induces ferroptosis in the liver.

As a metabolic disruptor, bisphenol A (BPA) has been widely reported to disrupt lipid balance. Moreover, BPA has gained significant attention due to its estrogenic activity. While both ferroptosis and the G-protein-coupled estrogen receptor (GPER) have been implicated in lipid metabolism, their link to BPA-induced lipid accumulation remains unclear. In this study, chickens were randomly assigned to three groups and housed them for 4 weeks: a control group (0 µg/L BPA), a low dose group (50 µg/L BPA) and a high dose group (5000 µg/L BPA) to investigate the underlying mechanism of BPA-induced hepatotoxicity. Our results showed that BPA exposure significantly increased the contents of TG, TC, and LDL-C while decreasing HDL-C levels. We also found that BPA treatment altered the levels of genes involved in fatty acid ß-oxidation (ampkα, cpt-1, and ppaα), synthesis (acc, fas, scd-1, and srebp-1) and absorption (lpl and cd36). Moreover, the results showed that the BPA group had higher levels of IL-1ß, IL-18 and TNF-α. These results indicated that BPA exposure disrupted lipid metabolism and induced inflammation in the liver. We also demonstrated that BPA caused hepatic ferroptosis by raising iron content and the expression of genes related to lipid peroxidation (lpcat3, acsl4 and alox15), while reducing the expression of antioxidant system-associated genes (gpx4, slc7a11 and slc3a2). Importantly, BPA remarkably activated GPER expression in the liver. Interestingly, inhibition of GPER remarkably ameliorated BPA-induced lipid metabolism disorder, inflammatory response, and ferroptosis, indicating the crucial role of GPER in BPA-induced liver abnormalities. These findings highlight the link between GPER and ferroptosis in BPA-induced hepatotoxicity, providing new insights into the potential hazard of BPA.

Construction and validation of a musculoskeletal disease risk prediction model for underground coal miners.

Objective: To understand the prevalence among underground coal miners of musculoskeletal disorders (MSDs), analyze the risk factors affecting MSDs, and develop and validate a risk prediction model for the development of MSDs. Materials and methods: MSD questionnaires were used to investigate the prevalence of work-related musculoskeletal disorders among 860 underground coal miners in Xinjiang. The Chinese versions of the Effort-Reward Imbalance Questionnaire (ERI), the Burnout Scale (MBI), and the Self-Rating Depression Inventory (SDS) were used to investigate the occupational mental health status of underground coal miners. The R4.1.3 software cart installation package was applied to randomly divide the study subjects into a 1:1 training set and validation set, screen independent predictors using single- and multi-factor regression analysis, and draw personalized nomogram graph prediction models based on regression coefficients. Subject work characteristic (ROC) curves, calibration (Calibrate) curves, and decision curves (DCA) were used to analyze the predictive value of each variable on MSDs and the net benefit. Results: (1) The prevalence of MSDs was 55.3%, 51.2%, and 41.9% since joining the workforce, in the past year, and in the past week, respectively; the highest prevalence was in the lower back (45.8% vs. 38.8% vs. 33.7%) and the lowest prevalence was in the hips and buttocks (13.3% vs. 11.4% vs. 9.1%) under different periods. (2) Underground coal miners: the mean total scores of occupational stress, burnout, and depression were 1.55 ± 0.64, 51.52 ± 11.53, and 13.83 ± 14.27, respectively. (3) Univariate regression revealed a higher prevalence of MSDs in those older than 45 years (49.5%), length of service > 15 years (56.4%), annual income <$60,000 (79.1%), and moderate burnout (43.2%). (4) Binary logistic regression showed that the prevalence of MSDs was higher for those with 5-20 years of service (OR = 0.295, 95% CI: 0.169-0.513), >20 years of service (OR = 0.845, 95% CI: 0.529-1.350), annual income ≥$60,000 (OR = 1.742, 95% CI: 1.100-2.759), and severe burnout (OR = 0.284, 95% CI: 0.109-0.739), and that these were independent predictors of the occurrence of MSDs among workers in underground coal mine operations (p < 0.05). (5) The areas under the ROC curve for the training and validation sets were 0.665 (95% CI: 0.615-0.716) and 0.630 (95% CI: 0.578-0.682), respectively, indicating that the model has good predictive ability; the calibration plots showed good agreement between the predicted and actual prevalence of the model; and the DCA curves suggested that the predictive value of this nomogram model for MSDs was good. Conclusion: The prevalence of MSDs among workers working underground in coal mines was high, and the constructed nomogram showed good discriminatory ability and optimal accuracy.

Shift work is associated with an increased risk of type 2 diabetes and elevated RBP4 level: cross sectional analysis from the OHSPIW cohort study.

BACKGROUND: Shift work, with its growing prevalence globally, disrupts the body's inherent circadian rhythm. This disruption may escalate the risk of chronic diseasesxacerbate chronic disease risk by dysregulating physiological, behavioral, and psychosocial pathways. This study aimed to evaluate the effect of shift work on type 2 diabetes (T2DM) and Retinol binding protein 4 (RBP4) level. METHODS: The current study employed a multi-stage stratified cluster sampling technique, examining 1499 oilfield workers from the OHSPIW cohort who participated in occupational health assessments between March 2017 and June 2018.The evaluation involved shift work, sleep quality, T2DM status with questionnaires and plasma RBP4 levels in blood samples. Statistical analysis includes, Chi-square tests, t-tests, multivariate logistic regression analyses, and multivariate linear mixed models. RESULTS: The prevalence rate of T2DM in shift workers (6.56%) was significantly higher than in day workers (4.21%) (OR = 1.60, 95% CI: 1.01-2.53), with no significant difference found in the family history of diabetes, hypertension, or other chronic heart diseases (P = 0.378). The shift worker (6.89 ± 3.35) also exhibited distinctly higher PSQI scores than day workers (5.99 ± 2.87) (P < 0.001). Adjusting the age, gender, BMI, family income, tobacco smoking, alcohol drinking and PSQI, hailed shift work as a risk factor for T2DM (OR = 1.91, 95% CI: 1.17-3.14). The pairwise comparison revealed significant differences in RBP4 levels across different groups: shift and non-shift workers both with and without T2DM (P < 0.001). The RBP4 level of the shift group without T2DM was higher than the non-shift group without T2DM (P < 0.05). The levels of RBP4 level in shift and non-shift groups with T2DM was higher than those without T2DM (P < 0.05). The multivariate linear mixed model showed that when age, gender, BMI, diabetes, PSQI, family income, smoking and drinking remained unchanged, the RBP4 level of the shift workers increased by an average of 9.51 µg/mL compared with the day workers. CONCLUSIONS: Shift work is associated with an increased risk of T2DM and high levels of RBP4. Follow-up of RBP4 could facilitateearly detection of T2DM among shift workers.

Phylotype resolved spatial variation and association patterns of planktonic Thaumarchaeota in eastern Chinese marginal seas.

The majority of marine ammonia oxidizers belong to Thaumarchaeota, a phylum of Archaea, which is distributed throughout the water column. Marine surface waters contain distinct thaumarchaeotal phylotypes compared to the deeper ocean, but spatial dynamics of the surface-associated lineages are largely unsolved. This study of 120 seawater samples from the eastern Chinese marginal seas identified contrasting distribution and association patterns among thaumarchaeotal phylotypes across different dimensions. Horizontally, Nitrosopumilus-like and Nitrosopelagicus-like phylotypes dominated the surface water (3 m) of the Yellow Sea (YS) and East China Sea (ECS), respectively, along with increased abundance of total free-living Thaumarchaeota in ECS. Similar compositional changes were observed in the surface microlayer. The spatial heterogeneity of particle-attached Thaumarchaeota was less clear in surface microlayers than in surface waters. Vertically, the Nitrosopelagicus-like phylotype increased in abundance from surface to 90 m in ECS, which led to an increase in the proportion of Thaumarchaeota relative to total prokaryotes. This occurred mainly in the free-living fraction. These results indicate a clear size-fractionated niche partitioning, which is more pronounced at lower depths than in the surface water/surface microlayer. In addition, associations of Thaumarchaeota with other microbial taxa varied between phylotypes and size fractions. Our results show that a phylotype-resolved and size-fractionated spatial heterogeneity of the thaumarchaeotal community is present in surface oceanic waters and a vertical variation of the Nitrosopelagicus-like phylotype is present in shallow shelf waters. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-023-00169-y.

A special satellite-like RNA of a novel hypovirus from Pestalotiopsis fici broadens the definition of fungal satellite.

Satellites associated with plant or animal viruses have been largely detected and characterized, while those from mycoviruses together with their roles remain far less determined. Three dsRNA segments (dsRNA 1 to 3 termed according to their decreasing sizes) were identified in a strain of phytopathogenic fungus Pestalotiopsis fici AH1-1 isolated from a tea leaf. The complete sequences of dsRNAs 1 to 3, with the sizes of 10316, 5511, and 631 bp, were determined by random cloning together with a RACE protocol. Sequence analyses support that dsRNA1 is a genome of a novel hypovirus belonging to genus Alphahypovirus of the family Hypoviridae, tentatively named Pestalotiopsis fici hypovirus 1 (PfHV1); dsRNA2 is a defective RNA (D-RNA) generating from dsRNA1 with septal deletions; and dsRNA3 is the satellite component of PfHV1 since it could be co-precipitated with other dsRNA components in the same sucrose fraction by ultra-centrifuge, suggesting that it is encapsulated together with PfHV1 genomic dsRNAs. Moreover, dsRNA3 shares an identical stretch (170 bp) with dsRNAs 1 and 2 at their 5' termini and the remaining are heterogenous, which is distinct from a typical satellite that generally has very little or no sequence similarity with helper viruses. More importantly, dsRNA3 lacks a substantial open reading frame (ORF) and a poly (A) tail, which is unlike the known satellite RNAs of hypoviruses, as well as unlike those in association with Totiviridae and Partitiviridae since the latters are encapsidated in coat proteins. As up-regulated expression of RNA3, dsRNA1 was significantly down-regulated, suggesting that dsRNA3 negatively regulates the expression of dsRNA1, whereas dsRNAs 1 to 3 have no obvious impact on the biological traits of the host fungus including morphologies and virulence. This study indicates that PfHV1 dsRNA3 is a special type of satellite-like nucleic acid that has substantial sequence homology with the host viral genome without encapsidation in a coat protein, which broadens the definition of fungal satellite.

Microbial Dimethylsulfoniopropionate Cycling in Deep Sediment of the Mariana Trench.

Dimethylsulfoniopropionate (DMSP) and related organic sulfur compounds play key roles in global sulfur cycling. Bacteria have been found to be important DMSP producers in seawater and surface sediments of the aphotic Mariana Trench (MT). However, detailed bacterial DMSP cycling in the Mariana Trench subseafloor remains largely unknown. Here, the bacterial DMSP-cycling potential in a Mariana Trench sediment core (7.5 m in length) obtained at a 10,816-m water depth was investigated using culture-dependent and -independent methods. The DMSP content fluctuated along the sediment depth and reached the highest concentration at 15 to 18 cm below the seafloor (cmbsf). dsyB was the dominant known DMSP synthetic gene, existing in 0.36 to 1.19% of the bacteria, and was identified in the metagenome-assembled genomes (MAGs) of previously unknown bacterial DMSP synthetic groups such as Acidimicrobiia, Phycisphaerae, and Hydrogenedentia. dddP, dmdA, and dddX were the major DMSP catabolic genes. The DMSP catabolic activities of DddP and DddX retrieved from Anaerolineales MAGs were confirmed by heterologous expression, indicating that such anaerobic bacteria might participate in DMSP catabolism. Moreover, genes involved in methanethiol (MeSH) production from methylmercaptopropionate (MMPA) and dimethyl sulfide (DMS), MeSH oxidation, and DMS production were highly abundant, suggesting active conversions between different organic sulfur compounds. Finally, most culturable DMSP synthetic and catabolic isolates possessed no known DMSP synthetic and catabolic genes, and actinomycetes could be important groups involved in both DMSP synthesis and catabolism in Mariana Trench sediment. This study extends the current understanding of DMSP cycling in Mariana Trench sediment and highlights the need to uncover novel DMSP metabolic genes/pathways in extreme environments. IMPORTANCE Dimethylsulfoniopropionate (DMSP) is an abundant organosulfur molecule in the ocean and is the precursor for the climate-active volatile gas dimethyl sulfide. Previous studies focused mainly on bacterial DMSP cycling in seawater, coastal sediment, and surface trench sediment samples, but DMSP metabolism in the Mariana Trench (MT) subseafloor sediments remains unknown. Here, we describe the DMSP content and metabolic bacterial groups in the subseafloor of the MT sediment. We found that the tendency for vertical variation of the DMSP content in the MT was distinct from that of the continent shelf sediment. Although dsyB and dddP were the dominant DMSP synthetic and catabolic genes in the MT sediment, respectively, both metagenomic and culture methods revealed multiple previously unknown DMSP metabolic bacterial groups, especially anaerobic bacteria and actinomycetes. The active conversion of DMSP, DMS, and methanethiol may also occur in the MT sediments. These results provide novel insights for understanding DMSP cycling in the MT.

Sedimentary Vibrio Blooms in the Xisha Islands May Associate with the 2020 Coral Bleaching Event.

Coral reefs are among the most biodiverse ecosystems, providing habitats for various organisms. Studies on coral bleaching have been increasing recently, but little is known about the distribution and community assembly of coral pathogenic bacteria (e.g., several Vibrio species). We elucidated the distribution pattern and interaction relationships of total bacteria and Vibrio spp. in sediments from the Xisha Islands, which are characterized by their high coverage and diversity of coral resources. Vibrio spp. showed significantly higher relative abundance values in the Xisha Islands (1.00 × 108 copies/g) than in other areas (approximately 1 × 104 to 9.04 × 105 copies/g), indicating that the coral bleaching event of 2020 may have promoted the bloom of vibrios. A spatial shift in community composition was observed between the northern (Photobacterium rosenbergii and Vibrio ponticus) and southern (Vibrio ishigakensis and Vibrio natriegens) sites, accompanied by a clear distance-decay pattern. The spatial distance and coral species (e.g., Acroporidae and Fungiidae) had much greater correlations with the Vibrio community than did environmental factors. However, complex mechanisms may exist in the community assembly of Vibrio spp. due to the large proportion of unexplained variation. Stochastic processes may play an important role, as shown by the neutral model. Vibrio harveyi had the highest relative abundance (77.56%) and niche breadth, compared to other species, and it was negatively correlated with Acroporidae, likely reflecting its strong competitive ability and adverse effects on specific corals. Our study provides insights into the bloom and underlying assembly mechanisms of sedimentary vibrios in the Xisha Islands, thereby contributing to identify the potential indicator of coral bleaching and provide inspiration for the environmental management of coral reef areas. IMPORTANCE Coral reefs exert important roles in maintaining the sustainability of marine ecosystems but decline worldwide due to various drivers, especially pathogenic microorganisms. Here, we investigated the distribution pattern and interactions of total bacteria and Vibrio spp. in the sediments from Xisha Islands during the coral bleaching event of 2020. Our results showed that the abundances of Vibrio (1.00 × 108 copies/g) were high across the whole sites, indicating the bloom of sedimentary Vibrio spp. Coral pathogenic Vibrio species were abundant in the sediments, likely reflecting adverse effects on several kinds of corals. The compositions of the Vibrio spp. were separated by geographical location, which was mainly attributable to the spatial distance and coral species. Overall, this work contributes by providing evidence for the outbreak of coral pathogenic vibrios. The pathogenic mechanism of the dominant species (especially V. harveyi) should be comprehensively considered by laboratory infection experiments in the future.

Endothelial Gata6 deletion reduces monocyte recruitment and proinflammatory macrophage formation and attenuates atherosclerosis through Cmpk2-Nlrp3 pathways.

Endothelial dysfunction results in chronic vascular inflammation, which is critical for the development of atherosclerotic diseases. Transcription factor Gata6 has been reported to regulate vascular endothelial cell activation and inflammation in vitro. Here, we aimed to explore the roles and mechanisms of endothelial Gata6 in atherogenesis. Endothelial cell (EC) specific Gata6 deletion was generated in the ApoeKO hyperlipidemic atherosclerosis mouse model. Atherosclerotic lesion formation, endothelial inflammatory signaling, and endothelial-macrophage interaction were examined in vivo and in vitro by using cellular and molecular biological approaches. EC-GATA6 deletion mice exhibited a significant decrease in monocyte infiltration and atherosclerotic lesion compared to littermate control mice. Cytosine monophosphate kinase 2 (Cmpk2) was identified as a direct target gene of GATA6 and EC-GATA6 deletion decreased monocyte adherence, migration and pro-inflammatory macrophage foam cell formation through regulation of the CMPK2-Nlrp3 pathway. Endothelial target delivery of Cmpk2-shRNA by intercellular adhesion molecule 2 (Icam-2) promoter-driven AAV9 carrying the shRNA reversed the Gata6 upregulation mediated elevated Cmpk2 expression and further Nlrp3 activation and thus attenuated atherosclerosis. In addition, C-C motif chemokine ligand 5 (Ccl5) was also identified as a direct target gene of Gata6 to regulate monocyte adherence and migration influencing atherogenesis. This study provides direct in vivo evidence of EC-GATA6 involvement in the regulation of Cmpk2-Nlrp3, as well as Ccl5, on monocyte adherence and migration in atherosclerosis development and advances our understanding of the in vivo mechanisms of atherosclerotic lesion development, and meanwhile provides opportunities for future therapeutic interventions.