Sulfurovum mangrovi sp. nov., an obligately chemolithoautotrophic, hydrogen-oxidizing bacterium isolated from coastal marine sediments.

A novel mesophilic, chemolithoautotrophic, hydrogen-oxidizing bacterium, designated strain ST1-3T, was isolated from mud sediment samples collected from mangroves in Jiulong River estuary. The cells were Gram-stain-negative, non-motile and rod-shaped. The temperature, pH and salinity ranges for growth of strain ST1-3T were 4-45 °C (optimum, 35 °C), pH 5.0-8.5 (optimum, pH 7.0) and 0-8.0 % (w/v) NaCl (optimum, 4.0 %). The isolate was an obligate chemolithoautotroph capable of growth using hydrogen as the only energy source, and molecular oxygen, thiosulphate and elemental sulphur as electron acceptors. The major cellular fatty acids of strain ST1-3T were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c). The major polar lipids were phosphatidylethanolamine, phosphatidyldimethyl ethanolamine and phosphatidylglycerol. The respiratory quinone was menaquinone-6. The genomic DNA G+C content was 43.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and core genes showed that the novel isolate belonged to the genus Sulfurovum and was most closely related to Sulfurovum lithotrophicum 42BKTT (94.7 % sequence identity). The average nucleotide identity and digital DNA-DNA hybridization values between ST1-3T and S. lithotrophicum 42BKTT were 74.6 and 16.3 %, respectively. On the basis of the phenotypic, phylogenetic and genomic data presented here, strain ST1-3T represents a novel species of the genus Sulfurovum, for which the name Sulfurovum mangrovi sp. nov. is proposed, with the type strain ST1-3T (=MCCC M25234T=KCTC 25639T).

Sulfurimonas marina sp. nov., an obligately chemolithoautotrophic, sulphur-oxidizing bacterium isolated from a deep-sea sediment sample from the South China Sea.

A novel marine bacterium, designated strain B2T, was isolated from a deep-sea sediment sample collected from the South China Sea. Cells were observed to be Gram-stain negative, motile and rod shaped with a single polar flagellum. B2T could grow at 10-45 °C (optimum, 35 °C), pH 4.5-9.0 (optimum, pH 7.0) and in the presence of 1.0-8.0 % (w/v) NaCl (optimum, 3.0%). The isolate grew chemolithoautotrophically with sulphide, elemental sulphur and thiosulphate as electron donors, carbon dioxide as the sole carbon source, and molecular oxygen as the sole electron acceptor. Molecular hydrogen did not support growth. The predominant fatty acids of B2T were C16 : 1ω7c, C16 : 0 and C18 : 1ω7c. The results of phylogenetic analysis based on 16S rRNA gene sequence indicated that B2T represented a member of the genus Sulfurimonas, with the highest similarity to the 16S rRNA gene sequences of Sulfurimonas indica NW8NT (95.9 %), Sulfurimonas crateris SN118T (95.7 %), Sulfurimonas xiamenensis 1-1NT (95.6 %) and Sulfurimonas paralvinellae GO25T (95.4 %). Sequence similarities to other members of the genus Sulfurimonas were less than 95.0 %. In addition, the average nucleotide identity (ANI) value and digital DNA-DNA hybridization (dDDH) estimate between B2T and S. indica NW8NT were 73.0 and 23.7 %, respectively. The size of the complete genome of B2T is 22 61 034 bp, with a DNA G+C content of 36.0 mol %. On the basis of the phenotypic, phylogenetic and genomic data presented here, strain B2T represent a novel species of the genus Sulfurimonas, for which the name Sulfurimonas marina sp. nov. is proposed, with the type strain B2T (=MCCC 1A14515T=KCTC 15852T).

Early identification and severity prediction of acute respiratory infection (ESAR): a study protocol for a randomized controlled trial.

BACKGROUND: The outbreak of SARS-CoV-2 at the end of 2019 sounded the alarm for early inspection on acute respiratory infection (ARI). However, diagnosis pathway of ARI has still not reached a consensus and its impact on prognosis needs to be further explored. METHODS: ESAR is a multicenter, open-label, randomized controlled, non-inferiority clinical trial on evaluating the diagnosis performance and its impact on prognosis of ARI between mNGS and multiplex PCR. Enrolled patients will be divided into two groups with a ratio of 1:1. Group I will be directly tested by mNGS. Group II will firstly receive multiplex PCR, then mNGS in patients with severe infection if multiplex PCR is negative or inconsistent with clinical manifestations. All patients will be followed up every 7 days for 28 days. The primary endpoint is time to initiate targeted treatment. Secondary endpoints include incidence of significant events (oxygen inhalation, mechanical ventilation, etc.), clinical remission rate, and hospitalization length. A total of 440 participants will be enrolled in both groups. DISCUSSION: ESAR compares the efficacy of different diagnostic strategies and their impact on treatment outcomes in ARI, which is of great significance to make precise diagnosis, balance clinical resources and demands, and ultimately optimize clinical diagnosis pathways and treatment strategies. Trial registration Clinicaltrial.gov, NCT04955756, Registered on July 9th 2021.

Evaluation of droplet digital PCR rapid detection method and precise diagnosis and treatment for suspected sepsis (PROGRESS): a study protocol for a multi-center pragmatic randomized controlled trial.

BACKGROUND: Sepsis is still a major public health concern and a medical emergency due to its high morbidity and mortality. Accurate and timely etiology diagnosis is crucial for sepsis management. As an emerging rapid and sensitive pathogen detection tool, digital droplet PCR (ddPCR) has shown promising potential in rapid identification of pathogens and antimicrobial resistance genes. However, the diagnostic value and clinical impact of ddPCR tests remains to be studied in patients with suspected sepsis. PROGRESS trial is aimed to evaluate the clinical effectiveness of a novel ddPCR assay compared with standard practice. METHODS: PROGRESS is a multicenter, open-label, pragmatic randomized controlled trial (pRCT) set in ten hospitals, including departments of infectious disease and intensive care units. In this study, a total of 2292 patients with suspected sepsis will be randomly assigned to two arms: the ddPCR group and the control group with a ratio of 3:1. The primary outcome is the diagnostic efficacy, that is, the sensitivity and specificity of the ddPCR assay compared with the synchronous blood culture. Secondary outcomes include the mortality rates and the mean Sequential Organ Failure Assessment (SOFA) score at follow-up time points, the length of stay in the hospital, the time to directed antimicrobial therapy, duration of broad-spectrum antibiotic use, and the EQ-5D-5L score on day 90. DISCUSSION: It is the first multicenter pragmatic RCT to explore the diagnostic efficacy and clinical impact of the ddPCR assay in patients with suspected sepsis, taking advantage of both RCT's ability to establish causality and the feasibility of pragmatic approaches in real-world studies (RWS). This trial will help us to get a comprehensive view of the assay's capacity for precise diagnosis and treatment of sepsis. It has the potential to monitor the pathogen load change and to guide the antimicrobial therapy, making a beneficial impact on the prognosis of sepsis patients. TRIAL REGISTRATION: ClinicalTrial.gov, NCT05190861. Registered January 13, 2022-'Retrospectively registered', https://clinicaltrials.gov/ct2/show/NCT05190861 .

Elemental sulfur reduction by a deep-sea hydrothermal vent Campylobacterium Sulfurimonas sp. NW10.

Sulfurimonas species (class Campylobacteria, phylum Campylobacterota) were globally distributed and especially predominant in deep-sea hydrothermal environments. They were previously identified as chemolithoautotrophic sulfur-oxidizing bacteria (SOB), whereas little is known about their potential in sulfur reduction. In this report, we found that the elemental sulfur reduction is quite common in different species of genus Sulfurimonas. To gain insights into the sulfur reduction mechanism, growth tests, morphology observation, as well as genomic and transcriptomic analyses were performed on a deep-sea hydrothermal vent bacterium Sulfurimonas sp. NW10. Scanning electron micrographs and dialysis tubing tests confirmed that elemental sulfur reduction occurred without direct contact of cells with sulfur particles while direct access strongly promoted bacterial growth. Furthermore, we demonstrated that most species of Sulfurimonas probably employ both periplasmic and cytoplasmic polysulfide reductases, encoded by genes psrA1 B1 CDE and psrA2 B2 , respectively, to accomplish cyclooctasulfur reduction. This is the first report showing two different sulfur reduction pathways coupled to different energy conservations could coexist in one sulfur-reducing microorganism, and demonstrates that most bacteria of Sulfurimonas could employ both periplasmic and cytoplasmic polysulfide reductases to perform cyclooctasulfur reduction. The capability of sulfur reduction coupling with hydrogen oxidation may partially explain the prevalenceof Sulfurimonas in deep-sea hydrothermal vent environments.

Thiomicrorhabdus sediminis sp. nov. and Thiomicrorhabdus xiamenensis sp. nov., novel sulfur-oxidizing bacteria isolated from coastal sediments and an emended description of the genus Thiomicrorhabdus.

Two novel Gram-strain-negative and rod-shaped bacteria, designated strain G1T and G2T, were isolated from sediment samples collected from the coast of Xiamen, PR China. The cells were motile by a single polar flagellum. Growth of strain G1T occurred at 10-40 °C (optimum, 30 °C), at pH 6.0-9.0 (optimum, pH 7.5) and with 5-1530 mM NaCl (optimum, 510 mM), while the temperature, pH and NaCl concentration ranges for G2T were 4-45 °C (optimum, 28 °C), pH 5.5-8.0 (optimum, pH 6.5) and 85-1530 mM NaCl (optimum, 340 mM). The two isolates were obligate chemolithoautotrophs capable of using thiosulfate, sulfide, elemental sulphur or tetrathionate as an energy source. Strain G1T used molecular oxygen or nitrite as an electron acceptor, while strain G2T used molecular oxygen as the sole electron acceptor. The dominant fatty acids of G1T and G2T were summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16 : 0 and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c). The DNA G+C content of G1T and G2T were 45.1 and 48.3 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain G1T and G2T were members of the genus Thiomicrorhabdus, and most closely related to Thiomicrorhabdus hydrogeniphila MAS2T (96.0 %) and Thiomicrorhabdus indica 13-15AT (95.4 %), respectively. The 16S rRNA gene sequence similarity between strains G1T and G2T was 95.8 %. Based on the phylogenetic, genomic and phenotypic data presented here, the isolate strains represent novel species of the genus Thiomicrorhabdus, for which the names Thiomicrorhabdus sediminis sp. nov. (type strain G1T=MCCC 1A14511T=KCTC 15841T) and Thiomicrorhabdus xiamenensis sp. nov. (type strain G2T=MCCC 1A14512T=KCTC 15842T) are proposed.

Sulfurimonas indica sp. nov., a hydrogen- and sulfur-oxidizing chemolithoautotroph isolated from a hydrothermal sulfide chimney in the Northwest Indian Ocean.

A novel mesophilic, hydrogen- and sulfur-oxidizing bacterium, designated strain NW8NT, was collected from a sulfide chimney at the deep-sea hydrothermal vent on the Carlsberg Ridge of the Northwest Indian Ocean. The cells were Gram-stain-negative, motile, short rods with a single polar flagellum. The temperature, pH and salinity ranges for growth of strain NW8NT were 4-40 °C (optimum, 33 °C), pH 4.5-7.5 (optimum, pH 5.5) and 340-680 mM NaCl (optimum, 510 mM). The isolate was an obligate chemolithoautotroph capable of growth using hydrogen, thiosulfate, sulfide or elemental sulphur as the sole energy source, carbon dioxide as the sole carbon source and molecular oxygen as the sole electron acceptor. The major cellular fatty acids of strain NW8NT were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The total size of its genome was 2 093 492 bp and the genomic DNA G+C content was 36.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and core genes showed that the novel isolate belonged to the genus Sulfurimonas and was most closely related to Sulfurimonas paralvinellae GO25T (97.4 % sequence identity). The average nucleotide identity and DNA-DNAhybridization values between strain NW8NT and S. paralvinellae GO25T was 77.8 and 21.1 %, respectively. Based on the phylogenetic, genomic and phenotypic data presented here, strain NW8NT represents a novel species of the genus Sulfurimonas, for which the name Sulfurimonas indica sp. nov. is proposed, with the type strain NW8NT (=MCCC 1A13988T=KTCC 15780T).

Upregulation of endothelial cell-derived exosomal microRNA-125b-5p protects from sepsis-induced acute lung injury by inhibiting topoisomerase II alpha.

OBJECTIVE: Emerging evidence has revealed that exosomal microRNAs (miRNAs) are implicated in human diseases. However, role of exosomal miR-125b-5p in sepsis-induced acute lung injury (ALI) remains further explored. We focused on the effect of exosomal miR-125b-5p on ALI progression via targeting topoisomerase II alpha (TOP2A). METHODS: The ALI mouse models were established by cecal ligation and perforation, which were then treated with miR-125b-5p agomir or overexpressed TOP2A. Next, the pathological structure of ALI mouse lung tissues were observed, miR-125b-5p, TOP2A and vascular endothelial growth factor (VEGF) expression was determined, and the lung water content, inflammatory response, protein content in bronchoalveolar lavage fluid (BALF) and cell apoptosis in ALI mouse lung tissues were assessed. Exosomes were extracted from endothelial cells (ECs) and identified, which were then injected into the modeled mice to observe their roles in ALI. The targeting relationship between miR-125b-5p and TOP2A was confirmed. RESULTS: MiR-125b-5p was downregulated while TOP2A was upregulated in ALI mice. MiR-125b-5p elevation or ECs-derived exosomes promoted VEGF expression, improved pathological changes and restrained lung water content, inflammatory response, protein content in BALF and cell apoptosis in lung tissues ALI mice. TOP2A overexpression reversed the repressive role of miR-125b-5p upregulation in ALI, while downregulated miR-125b-5p abrogated the effect of ECs-derived exosomes on ALI. TOP2A was confirmed as a direct target gene of miR-125b-5p. CONCLUSION: Our study indicates that ECs-derived exosomes overexpressed miR-125b-5p to protect from sepsis-induced ALI by inhibiting TOP2A, which may contribute to ALI therapeutic strategies.

Sulfurimonas sediminis sp. nov., a novel hydrogen- and sulfur-oxidizing chemolithoautotroph isolated from a hydrothermal vent at the Longqi system, southwestern Indian ocean.

A novel marine hydrogen- and sulfur-oxidizing bacterium, designated strain S2-6 T, was isolated from the deep-sea sediment samples at the Longqi hydrothermal system, southwestern Indian Ocean. Cells were Gram-stain-negative, motile, short rods with a single polar flagellum. Growth was observed at 10-45 °C (optimum 33 °C), pH 5.0-8.0 (optimum pH 7.0) and 1.5 to 6.0% (w/v) NaCl with an optimum at 3.0% (w/v). The isolate was an obligate chemolithoautotroph capable of growth using thiosulfate, tetrathionate, elemental sulfur or sodium sulfide as the energy source, and oxygen or nitrate as the sole electron acceptor. When hydrogen was used as the energy source, strain S2-6 T could respire oxygen, nitrate or element sulfur. The major cellular fatty acids of strain S2-6 T were summed feature 3 (C16:1ω7c and/or C16:1ω6c), C16:0 and summed feature 8 (C18:1ω7c and/or C18:1ω6c). The total size of its genome was 2,320,257 bp and the genomic DNA G + C content was 37.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and core genes showed that the novel isolate belonged to the genus Sulfurimonas and was most closely related to Sulfurimonas paralvinellae GO25T (96.8% sequence identity) and Sulfurimonas autotrophica OK10T (95.8% sequence identity). The average nucleotide identity and DNA-DNA hybridization values between strain S2-6 T and S. paralvinellae GO25T and S. autotrophica OK10T were 74.6%-81.2% and 19.1%-24.6%, respectively. Based on the polyphase taxonomical data, strain S2-6 T represents a novel species of the genus Sulfurimonas, for which the name Sulfurimonas sediminis sp. nov. is proposed, with the type strain S2-6 T (= MCCC 1A14513T = KCTC 15854 T).

Reversal of Multidrug Resistance by Apolipoprotein A1-Modified Doxorubicin Liposome for Breast Cancer Treatment.

Multidrug resistance (MDR) remains a major problem in cancer therapy and is characterized by the overexpression of p-glycoprotein (P-gp) efflux pump, upregulation of anti-apoptotic proteins or downregulation of pro-apoptotic proteins. In this study, an Apolipoprotein A1 (ApoA1)-modified cationic liposome containing a synthetic cationic lipid and cholesterol was developed for the delivery of a small-molecule chemotherapeutic drug, doxorubicin (Dox) to treat MDR tumor. The liposome-modified by ApoA1 was found to promote drug uptake and elicit better therapeutic effects than free Dox and liposome in MCF-7/ADR cells. Further, loading Dox into the present ApoA1-liposome systems enabled a burst release at the tumor location, resulting in enhanced anti-tumor effects and reduced off-target effects. More importantly, ApoA1-lip/Dox caused fewer adverse effects on cardiac function and other organs in 4T1 subcutaneous xenograft models. These features indicate that the designed liposomes represent a promising strategy for the reversal of MDR in cancer treatment.

"Candidatus Desulfobulbus rimicarensis," an Uncultivated Deltaproteobacterial Epibiont from the Deep-Sea Hydrothermal Vent Shrimp Rimicaris exoculata.

The deep-sea hydrothermal vent shrimp Rimicaris exoculata largely depends on a dense epibiotic chemoautotrophic bacterial community within its enlarged cephalothoracic chamber. However, our understanding of shrimp-bacterium interactions is limited. In this report, we focused on the deltaproteobacterial epibiont of R. exoculata from the relatively unexplored South Mid-Atlantic Ridge. A nearly complete genome of a Deltaproteobacteria epibiont was binned from the assembled metagenome. Whole-genome phylogenetic analysis reveals that it is affiliated with the genus Desulfobulbus, representing a potential novel species for which the name "Candidatus Desulfobulbus rimicarensis" is proposed. Genomic and transcriptomic analyses reveal that this bacterium utilizes the Wood-Ljungdahl pathway for carbon assimilation and harvests energy via sulfur disproportionation, which is significantly different from other shrimp epibionts. Additionally, this epibiont has putative nitrogen fixation activity, but it is extremely active in directly taking up ammonia and urea from the host or vent environments. Moreover, the epibiont could be distinguished from its free-living relatives by various features, such as the lack of chemotaxis and motility traits, a dramatic reduction in biosynthesis genes for capsular and extracellular polysaccharides, enrichment of genes required for carbon fixation and sulfur metabolism, and resistance to environmental toxins. Our study highlights the unique role and symbiotic adaptation of Deltaproteobacteria in deep-sea hydrothermal vent shrimps.IMPORTANCE The shrimp Rimicaris exoculata represents the dominant faunal biomass at many deep-sea hydrothermal vent ecosystems along the Mid-Atlantic Ridge. This organism harbors dense bacterial epibiont communities in its enlarged cephalothoracic chamber that play an important nutritional role. Deltaproteobacteria are ubiquitous in epibiotic communities of R. exoculata, and their functional roles as epibionts are based solely on the presence of functional genes. Here, we describe "Candidatus Desulfobulbus rimicarensis," an uncultivated deltaproteobacterial epibiont. Compared to campylobacterial and gammaproteobacterial epibionts of R. exoculata, this bacterium possessed unique metabolic pathways, such as the Wood-Ljungdahl pathway, as well as sulfur disproportionation and nitrogen fixation pathways. Furthermore, this epibiont can be distinguished from closely related free-living Desulfobulbus strains by its reduced genetic content and potential loss of functions, suggesting unique adaptations to the shrimp host. This study is a genomic and transcriptomic analysis of a deltaproteobacterial epibiont and largely expands the understanding of its metabolism and adaptation to the R. exoculata host.

Sulfurimonas xiamenensis sp. nov. and Sulfurimonas lithotrophica sp. nov., hydrogen- and sulfur-oxidizing chemolithoautotrophs within the Epsilonproteobacteria isolated from coastal sediments, and an emended description of the genus Sulfurimonas.

Strains 1-1NT and GYSZ_1T were isolated from marine sediments collected from the coast of Xiamen, PR China. Cells of the two strains were Gram-stain-negative, rod-shaped or slightly curved. Strain 1-1NT was non-motile, whereas strain GYSZ_1T was motile by means of one polar flagellum. The temperature, pH and salinity concentration ranges for growth of 1-1NT were 10-45 °C (optimum 30 °C), pH 5.5-8.0 (optimum 7.0) and 0-90 g l-1 NaCl (optimum 50 g l-1), while the growth of GYSZ_1T occurred at 4-45 °C (optimum 33 °C), pH 5.0-8.5 (optimum 6.5) and 5-90 g l-1 NaCl (optimum 20 g l-1). The two novel isolates were obligate chemolithoautotrophs capable of growth using hydrogen, thiosulfate, sulfide or elemental sulfur as the sole energy source, and nitrate, elemental sulfur or molecular oxygen as an electron acceptor. The major fatty acids of 1-1NT were C16 : 1ω7c, C16 : 0, C18 : 1ω7c and C18 : 0, while the predominant fatty acids of strain GYSZ_1T were C16 : 1ω7c, C16 : 0, C18 : 1ω7c and C14 : 0 3-OH. The DNA G+C contents of 1-1NT and GYSZ_1T were 34.5 mol% and 33.2 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that 1-1NT and GYSZ_1T represented members of the genus Sulfurimonas, with the highest sequence similarities to Sulfurimonas crateris SN118T (97.4 %) and Sulfurimonas denitrificans DSM 1251T (94.7 %), respectively. However, 1-1NT and GYSZ_1T shared 95.5 % similarity of 16S rRNA gene sequences, representing different species of the genus Sulfurimonas. On the basis of the physiological properties and the results of phylogenetic analyses, including average nucleotide identity and in silico DNA-DNA hybridization values, strains 1-1NT and GYSZ_1T represent two novel species within the genus Sulfurimonas, for which the names Sulfurimonas xiamenensis sp. nov. and Sulfurimonas lithotrophica sp. nov. are proposed, with the type strains 1-1NT (=MCCC 1A14514T=KCTC 15851T) and GYSZ_1T (=MCCC 1A14739T=KCTC 15853T), respectively. Our results also justify an emended description of the genus Sulfurimonas.

Thiomicrorhabdus indica sp. nov., an obligately chemolithoautotrophic, sulfur-oxidizing bacterium isolated from a deep-sea hydrothermal vent environment.

A new mesophilic bacterium, designated strain 13-15AT, was isolated from the deep-sea water from the Carlsberg Ridge, northwestern Indian Ocean. Cells were short rods and motile with a single polar flagellum. Growth was observed in the presence of 85-1700 mM NaCl (optimum 680 mM), at 10-45 °C (optimum, 28 °C) and pH 5.0-9.0 (optimum, pH 7.0). The isolate was an obligate chemolithoautotroph capable of growth using thiosulfate, sulfide, elemental sulfur or tetrathionate as the sole energy source, carbon dioxide as the sole carbon source, and molecular oxygen as the sole electron acceptor. Molecular hydrogen did not support growth. The major fatty acids were C16 : 1 (45.0 %), C18 : 1 (22.5 %) and C16 : 0 (20.1 %). The G+C content of the genomic DNA was 41.6 mol%. The results of phylogenetic analysis based on 16S rRNA gene sequences showed that the novel isolate belonged to the genus Thiomicrorhabdus and was most closely related to Thiomicrorhabdus hydrogeniphila MAS2T (94.8 % sequence similarity). On the basis of the taxonomic data obtained in this study, strain 13-15AT represents a novel species of the genus Thiomicrorhabdus, for which the name Thiomicrorhabdus indica sp. nov. is proposed, with the type strain 13-15AT (=MCCC 1A13986T=KCTC 15750T).

Sulfurovum indicum sp. nov., a novel hydrogen- and sulfur-oxidizing chemolithoautotroph isolated from a deep-sea hydrothermal plume in the Northwestern Indian Ocean.

A novel mesophilic, hydrogen-, and sulfur-oxidizing bacterium, designated strain ST-419T, was isolated from a deep-sea hydrothermal vent plume on the Carlsberg Ridge of the Northwestern Indian Ocean. The isolate was a Gram-staining-negative, non-motile and coccoid to oval-shaped bacterium. Growth was observed at 4-50 °C (optimum 37 °C), pH 5.0-8.6 (optimum pH 6.0) and 1.0-5.0 % (w/v) NaCl (optimum 3.0 %). ST-419T could grow chemlithoautotrophically with molecular hydrogen, sulfide, elemental sulfur and thiosulfate as energy sources. Molecular oxygen, nitrate and elemental sulfur could be used as electron acceptors. The predominant fatty acids were C16 : 1ω7c, C18 : 1ω7c and C16 : 0. The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The respiratory quinone was menaquinone MK-6 and the G+C content of the genomic DNA was 42.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that ST-419T represented a member of genus Sulfurovum and was most closely related to Sulfurovum riftiae 1812ET, with 97.6 % sequence similarity. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between ST-419T and S. riftiae 1812ET were 74.6 and 19.6 %, respectively. The combined genotypic and phenotypic data indicate that ST-419T represents a novel species within the genus Sulfurovum, for which the name Sulfurovum indicum sp. nov. is proposed. The type strain is ST-419T (=MCCC 1A17954T=KCTC 25164T).

[Diversity of culturable sulfur-oxidizing bacteria in deep-sea hydrothermal vent environments of the South Atlantic].

OBJECTIVE: To investigate the diversity of culturable sulfur-oxidizing bacteria in hydrothermal vent environments of the South Atlantic, and analyze their characteristics of sulfur oxidation. METHODS: We enriched and isolated sulfur-oxidizing bacteria from hydrothermal vent samples collected from the South Atlantic. The microbial diversity in enrichment cultures was analyzed using the Denatural Gradient Gel Electrophoresis method. Sulfur-oxidizing characteristics of the isolates was further studied by using ion chromatography. RESULTS: A total of 48 isolates were obtained from the deep-sea hydrothermal vent samples, which belonged to 23 genera and mainly grouped into alpha-Proteobacteria (58.3%), Actinobacteria (22.9%) and gama-Proteobacteria (18.8%). Among them, the genus Thalassospira, Martelella and Microbacterium were dominant. About 60% of the isolates exibited sulfur-oxidizing ability and strain L6M1-5 had a higher sulfur oxidation rate by comparison analysis. CONCLUSION: The diversity of sulfur-oxidizing bacteria in hydrothermal environments of the South Atlantic was reported for the first time based on culture-dependent methods. The result will help understand the biogechemical process of sulfur compounds in the deep-sea hydrothermal environments.

Multiple loci not only Rf3 involved in the restoration ability of pollen fertility, anther exsertion and pollen shedding to S type cytoplasmic male sterile in maize.

KEY MESSAGE: Thirty loci for fertility restoration of pollen fertility, anther exsertion and pollen shedding to maize CMS-S were identified by GWAS. S type cytoplasmic male sterile (CMS-S) is the main type of CMS in maize; poor understanding of the genetic architecture of fertility restoration to CMS-S is one of the reasons to impede its utility in hybrid breeding. In this study, genome-wide identification of genetic loci for fertility restoration ability to CMS-S was firstly conducted with a set of testcrossing association mapping panel in three environments. A total of 19, 3 and 8 significant loci (P < 1.8 × 10(-6), α = 1) for pollen fertility, anther exsertion and pollen shedding were identified, respectively, and individual locus explained up to 28.26% of phenotypic variation. Of them, only Rf3, the main restorer-fertility gene of CMS-S, was identified for the three traits simultaneously. In addition, 83 candidate genes within the 100 kb extension regions of these loci were predicted. These results revealed that besides Rf3 multiple genetic loci and mechanisms are involved in the fertility restoration ability to CMS-S. Results in this study would provide important information for understanding the genetic architecture of fertility restoration to CMS-S in maize.

Mameliella atlantica sp. nov., a marine bacterium of the Roseobacter clade isolated from deep-sea sediment of the South Atlantic Ocean.

A taxonomic study was carried out on strain L6M1-5(T), which was isolated from deep-sea sediment collected from the South Atlantic Ocean. The isolate was Gram-reaction-negative, oxidase-negative and catalase-weakly positive. Growth was observed in the presence of 0.5-15% (w/v) NaCl (optimum 3-5%), at 10-41 °C (optimum 28-30 °C), and pH 5.0-10.5 (optimum pH 7.0). The principal fatty acids were summed feature 8 (C18 : 1ω7c/ω6c) (84.2%), C18 : 0 (6.3%), C12 : 1 3-OH (3.2%) and C16 : 0 (2.7%). The polar lipid profile comprised phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids, two unknown phospholipids and one unknown lipid. Ubiquinone-10 was the major quinone. The G+C content of the genomic DNA was 66.0 mol %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain L6M1-5(T) belonged to the genus Mameliella and shared 95.8% sequence similarity with Mameliella alba JLT354-W(T). The combined genotypic and phenotypic data show that strain L6M1-5(T) represents a novel species of the genus Mameliella, for which the name Mameliella. atlantica sp. nov. is proposed. The type strain is L6M1-5(T) ( = MCCC 1A07531(T) = JCM 30230(T)).

Thioclava indica sp. nov., isolated from surface seawater of the Indian Ocean.

A short-rod shaped, non-motile and Gram-negative strain, designated as DT23-4(T), was isolated from a dotriacontane-degrading bacterial consortium, enriched in the surface seawater of the Indian Ocean. To delineate its taxonomic position, strain DT23-4(T) was subjected to polyphasic characterization. Strain DT23-4(T) can grow at temperatures from 10 to 41 °C, in the range of pH 6-10 and at salinities from 0 to 18 % (w/v). It is positive for denitrification, oxidase and catalase, but negative for gelatin hydrolysis and indole production. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain DT23-4(T) affiliates to the genus Thioclava, sharing high sequence similarity to Thioclava dalianensis DLFJ1-1(T) (98.2 %), Thioclava atlantica 13D2W-2(T) (96.8 %), Thioclava pacifica TL 2(T) (95.9 %) and less than 95.7 % with other species of the family Rhodobacteraceae. The digital DNA:DNA hybridization (dDDH) pairwise values between strain DT23-4(T) and T. dalianensis DLFJ1-1(T), T. atlantica 13D2W-2(T) and T. pacifica TL 2(T) were 21.5 ± 2.3, 20.6 ± 2.3 and 20.9 ± 2.3 %, respectively. Similarly, the average nucleotide identity values between strain DT23-4(T) and these three type strains were 78.0, 77.1 and 77.3 %, respectively. The principal fatty acid was identified as Summed Feature 8 (C18:1 ω7c/ω6c) (81.9 %). The quinone of strain DT23-4(T) was identified as Q10 (100 %). The polar lipids of strain DT23-4(T) were found to contain phosphatidylethanolamine, phosphatidylglycerol, two glycolipids and four phospholipids. The genomic DNA G+C content was determined to be 60.3 mol%. On the basis of genotypic, phenotypic and chemotaxonomic analyses, strain DT23-4(T) can be concluded to represent a novel species of the genus Thioclava, for which the name Thioclava indica sp. nov. is proposed, with the type strain DT23-4(T) (= MCCC 1A00513(T) = LMG 27698(T) = KCTC 33533(T)).

Defluviimonas indica sp. nov., a marine bacterium isolated from a deep-sea hydrothermal vent environment.

A Gram-stain-negative, strictly aerobic, chemoheterotrophic marine bacterium, designated 20V17(T), was isolated from a deep-sea hydrothermal vent chimney collected from the South-west Indian Ridge. Cells of strain 20V17(T) were motile, short rods, 1.2-1.8 µm in length and 0.5-0.7 µm in width. Growth was observed at between 20 and 37 °C (optimum 25 °C-28 °C), pH 5.0 and 8.0 (optimum pH 7.0) and 0.5 and 8% (w/v) NaCl (optimum 1.5-2.0% NaCl). The major fatty acids were C(18 : 1)ω7c (74.4%), C(19 : 0) cyclo ω8c (11%), C(18 : 0) (5.1%) and C(18 : 0) 3-OH (2.8%), and the polar lipid profile comprised diphosphatidylglycerol, phosphatidylethanolamine, an unidentified glycolipid and four unidentified phospholipids. Ubiquinone 10 was the major quinone. The G+C content of genomic DNA was 66.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 20V17(T) belonged to the genus Defluviimonas and shared 96.5 and 96.1% sequence similarity with Defluviimonas denitrificans D9-3(T) and Defluviimonas aestuarii BS14(T), respectively. On the basis of the taxonomic data obtained in this study, strain 20V17(T) represents a novel species of the genus Defluviimonas, for which the name Defluviimonas indica sp. nov. is proposed. The type strain is 20V17(T) (CGMCC 1.10859(T) = JCM 17871(T) = MCCC 1A01802(T)).

Kosmotoga pacifica sp. nov., a thermophilic chemoorganoheterotrophic bacterium isolated from an East Pacific hydrothermal sediment.

A novel strictly anaerobic thermophilic heterotrophic bacterium, strain SLHLJ1(T), was isolated from a Pacific hydrothermal sediment. Cells were Gram-negative coccobacilli (approximately 1.0 × 0.6 µm) with a toga. It grew at temperatures between 33 and 78 °C (optimum 70 °C). Elemental sulphur and L-cystine stimulated its growth. It contained C16:0, C16:1 ω11c, C18:0 and C18:1 ω9c as major fatty acids (>5%), 3 phospholipids and 2 glycolipids as polar lipids. Its DNA G+C content was 43.7 mol%. Phylogenetic analyses based on 16S rRNA gene sequences placed strain SLHLJ1(T) within the family Thermotogaceae. The novel isolate was most closely related to Kosmotoga arenicorallina (97.93 % 16S rRNA gene sequence similarity), K. olearia (92.43%) and K. shengliensis (92.17 %). On the basis of phenotypic, chemotaxonomic and phylogenetic comparisons with its closest relatives, we propose its assignment to a novel species of the genus Kosmotoga. The name Kosmotoga pacifica sp. nov. is proposed with strain SLHLJ1(T) (=DSM 26965(T) = JCM 19180(T) = UBOCC 3254(T)) as the type species.