Biodegradation of low-density polyethylene film by two bacteria isolated from plastic debris in coastal beach.

Low-density polyethylene (LDPE) conduces massive environmental accumulation due to its high production and recalcitrance to environment. In this study, We successfully enriched and isolated two strains, Nitratireductor sp. Z-1 and Gordonia sp. Z-2, from coastal plastic debris capable of degrading LDPE film. After a 30-day incubation at 30 ℃, strains Z-1 and Z-2 decreased the weight of branched-LDPE (BLDPE) film by 2.59 % and 10.27 % respectively. Furthermore, high temperature gel permeation chromatography (HT-GPC) analysis revealed molecular weight reductions of 7.69 % (Z-1) and 23.22 % (Z-2) in the BLDPE film. Scanning electron microscope (SEM) image showed the presence of microbial colonization and perforations on the film's surface. Fourier transform infrared spectroscopy (FTIR) analysis indicated novel functional groups, such as carbonyl and carbon-carbon double bonds in LDPE films. During LDPE degradation, both strains produced extracellular reactive oxygen species (ROS). GC-MS analysis revealed the degradation products included short-chain alkanes, alkanols, fatty acids, and esters. Genomic analysis identified numerous extracellular enzymes potentially involved in LDPE chain scission. A model was proposed suggesting a coordinated role between ROS and extracellular enzymes in the biodegradation of LDPE. This indicates strains Z-1 and Z-2 can degrade LDPE, providing a basis for deeper exploration of biodegradation mechanisms.

Aerobic Anoxygenic Phototrophic Bacteria in the Marine Environments Revealed by Raman/Fluorescence-Guided Single-Cell Sorting and Targeted Metagenomics.

Aerobic anoxygenic phototrophic bacteria (AAPB) contribute profoundly to the global carbon cycle. However, most AAPB in marine environments are uncultured and at low abundance, hampering the recognition of their functions and molecular mechanisms. In this study, we developed a new culture-independent method to identify and sort AAPB using single-cell Raman/fluorescence spectroscopy. Characteristic Raman and fluorescent bands specific to bacteriochlorophyll a (Bchl a) in AAPB were determined by comparing multiple known AAPB with non-AAPB isolates. Using these spectroscopic biomarkers, AAPB in coastal seawater, pelagic seawater, and hydrothermal sediment samples were screened, sorted, and sequenced. 16S rRNA gene analysis and functional gene annotations of sorted cells revealed novel AAPB members and functional genes, including one species belonging to the genus Sphingomonas, two genera affiliated to classes Betaproteobacteria and Gammaproteobacteria, and function genes bchCDIX, pucC2, and pufL related to Bchl a biosynthesis and photosynthetic reaction center assembly. Metagenome-assembled genomes (MAGs) of sorted cells from pelagic seawater and deep-sea hydrothermal sediment belonged to Erythrobacter sanguineus that was considered as an AAPB and genus Sphingomonas, respectively. Moreover, multiple photosynthesis-related genes were annotated in both MAGs, and comparative genomic analysis revealed several exclusive genes involved in amino acid and inorganic ion metabolism and transport. This study employed a new single-cell spectroscopy method to detect AAPB, not only broadening the taxonomic and genetic contents of AAPB in marine environments but also revealing their genetic mechanisms at the single-genomic level.

Flagellimonas baculiformis sp. nov. and Flagellimonas crocea sp. nov., isolated from surface seawater of the Pacific Ocean.

Two Gram-negative, non-spore-forming, non-motile, non-flagellated bacteria, designated strains D6T and DH64T, were isolated from surface water of the Pacific Ocean. For strain D6T, growth occurred at 10-40 °C, pH 5.5-9.0 and in the presence of 0-8.0 % NaCl (w/v). For strain DH64T, growth occurred at 10-40 °C, pH 5.5-8.5 and in the presence of 0.5-8.0 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains D6T and DH64T both belonged to the genera Flagellimonas, with the highest sequence identities to Flagellimonas taeanensis JCM 17757T (98.2 %) and Flagellimonas marinaquae JCM 11811T (98.6 %), respectively. The 16S rRNA gene sequence identity between strains D6T and DH64T was 95.9 %. The average amino acid identity and digital DNA-DNA hybridization values between the two strains and the nearest phylogenetic neighbours were 66.7-93.3 % and 16.1-38.5 %, respectively. The major respiratory quinone of both strains was menaquinone-6. The major polar lipid was phosphatidylethanolamine. The major fatty acids were identified similarly as iso-C15 : 1 G, iso-C15 : 0 and iso-C17 : 0 3-OH. The genomic G+C contents of strains D6T and DH64T were determined to be 45.5 and 42.6 mol%, respectively. The combined genotypic and phenotypic data show that the strains represent two novel species within genera Flagellimonas, for which the names Flagellimonas baculiformis sp. nov. and Flagellimonas crocea sp. nov. are proposed, with type strains D6T (=MCCC M28982T=KCTC 92604T) and DH64T (=MCCC M28986T=KCTC 92975T).

Qipengyuania benthica sp. nov. and Qipengyuania profundimaris sp. nov., two novel Erythrobacteraceae members isolated from deep-sea environments.

Two Gram-stain-negative, rod-shaped and non-motile strains, designated as DY56-A-20T and G39T, were isolated from deep-sea sediment of the Pacific Ocean and deep-sea seawater of the Indian Ocean, respectively. Strain DY56-A-20T was found to grow at 15-37 °C (optimum, 28 °C), at pH 6.0-10.0 (optimum, pH 6.5-7.0) and in 0.5-6.0 % (w/v) NaCl (optimum, 1.0-2.0 %), while strain G39T was found to grow at 10-42 °C (optimum, 35-40 °C), at pH 5.5-10.0 (optimum, pH 6.5-7.0) and in 0-12.0 % (w/v) NaCl (optimum, 1.0-2.0 %). The 16S rRNA gene sequence identity analysis indicated that strain DY56-A-20T had the highest sequence identity with Qipengyuania marisflavi KEM-5T (97.6 %), while strain G39T displayed the highest sequence identity with Qipengyuania citrea H150T (98.8 %). The phylogenomic reconstruction indicated that both strains formed independent clades within the genus Qipengyuania. The digital DNA-DNA hybridization and average nucleotide identity values between strains DY56-A-20T/G39T and Qipengyuania/Erythrobacter type strains were 17.8-23.8 % and 70.7-81.1 %, respectively, which are below species delineation thresholds. The genome DNA G+C contents were 65.0 and 63.5 mol% for strains DY56-A-20T and G39T, respectively. The predominant cellular fatty acids (>10 %) of strain DY56-A-20T were C17 : 1 ω6c, summed feature 8 and summed feature 3, and the major cellular fatty acids of strain G39T were C17 : 1 ω6c and summed feature 8. The major polar lipids in both strains were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and an unidentified polar lipid. The only respiratory quinone present in both strains was ubiquinone-10. Based on those genotypic and phenotypic results, the two strains represent two novel species belonging to the genus Qipengyuania, for which the names Qipengyuania benthica sp. nov. and Qipengyuania profundimaris sp. nov. are proposed. The type strain of Q. benthica is DY56-A-20T (=MCCC M27941T=KCTC 92309T), and the type strain of Q. profundimaris is G39T (=MCCC M30353T=KCTC 8208T).

Genomic insight into strategy, interaction and evolution of nitrifiers in metabolizing key labile-dissolved organic nitrogen in different environmental niches.

Ammonia-oxidizing archaea (AOA) and bacteria (AOB), nitrite-oxidizing bacteria (NOB), and complete ammonia oxidizers (comammox) are responsible for nitrification in nature; however, some groups have been reported to utilize labile-dissolved organic nitrogen (LDON) for satisfying nitrogen demands. To understand the universality of their capacity of LDON metabolism, we collected 70 complete genomes of AOA, AOB, NOB, and comammox from typical environments for exploring their potentials in the metabolism of representative LDON (urea, polyamines, cyanate, taurine, glycine betaine, and methylamine). Genomic analyses showed that urea was the most popular LDON used by nitrifiers. Each group harbored unique urea transporter genes (AOA: dur3 and utp, AOB: utp, and NOB and comammox: urtABCDE and utp) accompanied by urease genes ureABC. The differentiation in the substrate affinity of these transporters implied the divergence of urea utilization efficiency in nitrifiers, potentially driving them into different niches. The cyanate transporter (cynABD and focA/nirC) and degradation (cynS) genes were detected mostly in NOB, indicating their preference for a wide range of nitrogen substrates to satisfy high nitrogen demands. The lack of genes involved in the metabolism of polyamines, taurine, glycine betaine, and methylamines in most of nitrifiers suggested that they were not able to serve as a source of ammonium, only if they were degraded or oxidized extracellularly as previously reported. The phylogenetic analyses assisted with comparisons of GC% and the Codon Adaptation Index between target genes and whole genomes of nitrifiers implied that urea metabolic genes dur3 and ureC in AOA evolved independently from bacteria during the transition from Thaumarchaeota to AOA, while utp in terrestrial AOA was acquired from bacteria via lateral gene transfer (LGT). Cyanate transporter genes cynS and focA/nirC detected only in a terrestrial AOA Candidadus Nitrsosphaera gargensis Ga9.2 could be gained synchronously with Nitrospira of NOB by an ancient LGT. Our results indicated that LDON utilization was a common feature in nitrifiers, but metabolic potentials were different among nitrifiers, possibly being intensely interacted with their niches, survival strategies, and evolutions.

Microbe-driven elemental cycling enables microbial adaptation to deep-sea ferromanganese nodule sediment fields.

BACKGROUND: Ferromanganese nodule-bearing deep-sea sediments cover vast areas of the ocean floor, representing a distinctive habitat in the abyss. These sediments harbor unique conditions characterized by high iron concentration and low degradable nutrient levels, which pose challenges to the survival and growth of most microorganisms. While the microbial diversity in ferromanganese nodule-associated sediments has been surveyed several times, little is known about the functional capacities of the communities adapted to these unique habitats. RESULTS: Seven sediment samples collected adjacent to ferromanganese nodules from the Clarion-Clipperton Fracture Zone (CCFZ) in the eastern Pacific Ocean were subjected to metagenomic analysis. As a result, 179 high-quality metagenome-assembled genomes (MAGs) were reconstructed and assigned to 21 bacterial phyla and 1 archaeal phylum, with 88.8% of the MAGs remaining unclassified at the species level. The main mechanisms of resistance to heavy metals for microorganisms in sediments included oxidation (Mn), reduction (Cr and Hg), efflux (Pb), synergy of reduction and efflux (As), and synergy of oxidation and efflux (Cu). Iron, which had the highest content among all metallic elements, may occur mainly as Fe(III) that potentially functioned as an electron acceptor. We found that microorganisms with a diverse array of CAZymes did not exhibit higher community abundance. Instead, microorganisms mainly obtained energy from oxidation of metal (e.g., Mn(II)) and sulfur compounds using oxygen or nitrate as an electron acceptor. Chemolithoautotrophic organisms (Thaumarchaeota and Nitrospirota phyla) were found to be potential manganese oxidizers. The functional profile analysis of the dominant microorganisms further indicated that utilization of inorganic nutrients by redox reactions (rather than organic nutrient metabolism) is a major adaptive strategy used by microorganisms to support their survival in the ferromanganese nodule sediments. CONCLUSIONS: This study provides a comprehensive metagenomic analysis of microbes inhabiting metal-rich ferromanganese nodule sediments. Our results reveal extensive redundancy across taxa for pathways of metal resistance and transformation, the highly diverse mechanisms used by microbes to obtain nutrition, and their participation in various element cycles in these unique environments. Video Abstract.

Global analysis of the biosynthetic chemical space of marine prokaryotes.

BACKGROUND: Marine prokaryotes are a rich source of novel bioactive secondary metabolites for drug discovery. Recent genome mining studies have revealed their great potential to bio-synthesize novel secondary metabolites. However, the exact biosynthetic chemical space encoded by the marine prokaryotes has yet to be systematically evaluated. RESULTS: We first investigated the secondary metabolic potential of marine prokaryotes by analyzing the diversity and novelty of the biosynthetic gene clusters (BGCs) in 7541 prokaryotic genomes from cultivated and single cells, along with 26,363 newly assembled medium-to-high-quality genomes from marine environmental samples. To quantitatively evaluate the unexplored biosynthetic chemical space of marine prokaryotes, the clustering thresholds for constructing the biosynthetic gene cluster and molecular networks were optimized to reach a similar level of the chemical similarity between the gene cluster family (GCF)-encoded metabolites and molecular family (MF) scaffolds using the MIBiG database. The global genome mining analysis demonstrated that the predicted 70,011 BGCs were organized into 24,536 mostly new (99.5%) GCFs, while the reported marine prokaryotic natural products were only classified into 778 MFs at the optimized clustering thresholds. The number of MF scaffolds is only 3.2% of the number of GCF-encoded scaffolds, suggesting that at least 96.8% of the secondary metabolic potential in marine prokaryotes is untapped. The unexplored biosynthetic chemical space of marine prokaryotes was illustrated by the 88 potential novel antimicrobial peptides encoded by ribosomally synthesized and post-translationally modified peptide BGCs. Furthermore, a sea-water-derived Aquimarina strain was selected to illustrate the diverse biosynthetic chemical space through untargeted metabolomics and genomics approaches, which identified the potential biosynthetic pathways of a group of novel polyketides and two known compounds (didemnilactone B and macrolactin A 15-ketone). CONCLUSIONS: The present bioinformatics and cheminformatics analyses highlight the promising potential to explore the biosynthetic chemical diversity of marine prokaryotes and provide valuable knowledge for the targeted discovery and biosynthesis of novel marine prokaryotic natural products. Video Abstract.

Metagenome-based analysis of carbon-fixing microorganisms and their carbon-fixing pathways in deep-sea sediments of the southwestern Indian Ocean.

Carbon fixation by chemoautotrophic microorganisms in the dark ocean makes a large contribution to oceanic primary production and the global carbon cycle. In contrast to the Calvin cycle-dominated carbon-fixing pathway in the marine euphotic zone, carbon-fixing pathways and their hosts in deep-sea areas are diverse. In this study, four deep-sea sediment samples close to hydrothermal vents in the southwestern Indian Ocean were collected and processed using metagenomic analysis to investigate carbon fixation potential. Functional annotations revealed that all six carbon-fixing pathways had genes to varied degrees present in the samples. The reductive tricarboxylic acid cycle and Calvin cycle genes occurred in all samples, in contrast to the Wood-Ljungdahl pathway, which previous studies found mainly in the hydrothermal area. The annotations also elucidated the chemoautotrophic microbial members associated with the six carbon-fixing pathways, and the majority of them containing key carbon fixation genes belonged to the phyla Pseudomonadota and Desulfobacterota. The binned metagenome-assembled genomes revealed that key genes for the Calvin cycle and the 3-hydroxypropionate/4-hydroxybutyrate cycle were also found in the order Rhodothermales and the family Hyphomicrobiaceae. By identifying the carbon metabolic pathways and microbial populations in the hydrothermal fields of the southwest Indian Ocean, our study sheds light on complex biogeochemical processes in deep-sea environments and lays the foundation for further in-depth investigations of carbon fixation processes in deep-sea ecosystems.

Microbulbifer zhoushanensis sp. nov., Microbulbifer sediminum sp. nov. and Microbulbifer guangxiensis sp. nov., three marine bacteria isolated from a tidal flat.

Three strains, TT30T, TT37T and L3T, were isolated from tidal flat samples. Cells were Gram-stain-negative, non-motile and rod shaped. Cells of strains TT30T and TT37T were able to grow in a medium containing 1.0-15.0 % (w/v) NaCl (optimum, 3.0 and 4.0 %, respectively), and cells of strain L3T was able to grow in a medium containing 1.0-10.0 % (w/v) NaCl (optimum, 1.0 %). Growth of the three strains was observed at pH 6.0-10.0 and at 10-40 °C. Strains TT30T, TT37T and L3T showed the highest similarity to Microbulbifer hydrolyticus DSM 11525T (97.7 %), M. yueqingensis CGMCC 1.10658T (98.0 %) and M. elongatus DSM 6810T (97.9 %), respectively. Results of phylogenetic analyses indicated that the three isolates represented two distinct lineages within the genus Microbulbifer. The DNA G+C contents of strains TT30T, TT37T and L3T were 61.3, 60.9 and 60.2%, respectively. The average nucleotide identity and in silico DNA-DNA hybridization values among strains TT30T, TT37T and L3T and the reference strains were 84.4-87.4 and 19.6-28.9 %, respectively. Differential phenotypic properties, chemotaxonomic differences, phylogenetic distinctiveness, together with the genomic data, demonstrated that strains TT30T, TT37 T and L3T represent novel species of the genus Microbulbifer, which are named Microbulbifer zhoushanensis sp. nov. (TT30T=KCTC 92167T=MCCC 1K07276T), Microbulbifer sediminum sp. nov. (TT37T=KCTC 92168T=MCCC 1K07277T) and Microbulbifer guangxiensis sp. nov. (L3T=KCTC 92165T=MCCC 1K07278T).

The effect of barium and strontium on activity of glucoamylase QsGH97a from Qipengyuania seohaensis SW-135.

Glycoside hydrolases (GHs), the enzymes that break glycosidic bonds, are ubiquitous in the ecosystem, where they perform a range of biological functions. As an interesting glycosidase family, Glycoside hydrolase family 97 (GH97) contains α-glucosidase, α-galactosidase, and glucoamylase. Only ten members of GH97 have been characterized so far. It is critical to explore novel members to elucidate the catalytic mechanism and application potential of GH97 family. In this study, a novel glucoamylase QsGH97a from Qipengyuania seohaensis SW-135 was cloned and expressed in E. coli. Sequence analysis and NMR results show that QsGH97a is classified into GH97a, and adopts inverting mechanism. The biochemical characterization indicates that QsGH97a shows the optimal activity at 50 °C and pH 8.0. Ca2+ has little effect on the catalytic activity; however, the activity can be substantially increased by 8-13 folds in the presence of Ba2+ or Sr2+. Additionally, the metal content of QsGH97a assay showed a high proportion of Sr2+. The specific metal activity was initially revealed in glucoamylases, which is not found in other members. These results imply that QsGH97a not only is a new member of GH97, but also has potential for industrial applications. Our study reveals that Ba2+ or Sr2+ may be involved in the catalytic mechanism of glucoamylase, laying the groundwork for a more complete knowledge of GH97 and its possible industrial application.

Understanding the mechanisms of halotolerance in members of Pontixanthobacter and Allopontixanthobacter by comparative genome analysis.

Halotolerant microorganisms have developed versatile mechanisms for coping with saline stress. With the increasing number of isolated halotolerant strains and their genomes being sequenced, comparative genome analysis would help understand the mechanisms of salt tolerance. Six type strains of Pontixanthobacter and Allopontixanthobacter, two phylogenetically close genera, were isolated from diverse salty environments and showed different NaCl tolerances, from 3 to 10% (w/v). Based on the co-occurrence greater than 0.8 between halotolerance and open reading frame (ORF) among the six strains, possible explanations for halotolerance were discussed regarding osmolyte, membrane permeability, transportation, intracellular signaling, polysaccharide biosynthesis, and SOS response, which provided hypotheses for further investigations. The strategy of analyzing genome-wide co-occurrence between genetic diversity and physiological characteristics sheds light on how microorganisms adapt to the environment.

Membranihabitans maritimus sp. nov., a marine bacterium isolated from deep seawater.

A Gram-stain-negative, non-motile, rod-shaped bacterial strain, designated C281T, was isolated from seawater sampled at the Marshallese seamount chain. Results of 16S rRNA gene analysis revealed that strain C281T was most closely related to Membranihabitans marinus CZ-AZ5T with 92.7 % sequence similarity. Phylogenetic analysis indicated that the new isolate represented a novel species by forming a distinctive lineage within the family Saprospiraceae. The DNA G+C content of strain C281T was 38.4 mol%. The genome sizes of strain C281T and the reference strain M. marinus CZ-AZ5T were 5 962 917 and 5 395 999 bp, respectively. The average nucleotide identity and in silico DNA-DNA hybridization values between strains C281T and M. marinus CZ-AZ5T were found to be low (69.3 and 17.6 %, respectively). Different functional genes were found in the genome of strain C281T, such as CZC CBA, polysaccharide utilization loci and linear azol(in)e-containing peptide cluster coding genes. The NaCl range for growth was 0.5-15.0 %. Positive results were obtained for hydrolysis of Tween 60 and urease. MK-7 was the sole respiratory quinone. The major fatty acids were C16 : 1 ω6c and/or C16 : 1 ω7c, iso-C15 : 0 and iso-C15 : 1 F. The major polar lipids of strain C281T were phosphatidylethanolamine, phosphatidylglycerol, two unidentified lipids and five unidentified glycolipids. On the basis of its taxonomic characteristics, the isolate represents a novel species of the genus Membranihabitans, for which the name Membranihabitans maritimus sp. nov. (type strain C281T=KCTC 92171T=MCCC M27001T) is proposed.

Secondary Metabolic Potential of Kutzneria.

Kutzneria is a rare genus of Actinobacteria that harbors a variety of secondary metabolite gene clusters and produces several interesting types of bioactive secondary metabolites. Recent efforts have partially elucidated the biosynthetic pathways of some of these bioactive natural products, suggesting the diversity and specificity of secondary metabolism within this genus. Here, we summarized the chemical structures, biosynthetic pathways, and key metabolic enzymes of the secondary metabolites isolated from Kutzneria strains. In-depth comparative genomic analysis of all six available high-quality Kutzneria genomes revealed that the majority (77%) of the biosynthetic gene cluster families of Kutzneria were untapped and identified homologues of key metabolic enzymes in the putative gene clusters, including cytochrome P450s, halogenases, and flavin-dependent N-hydroxylases. The present study suggests that Kutzneria exhibits great potential to synthesize novel secondary metabolites, encodes a variety of valuable metabolic enzymes, and also provides valuable information for the targeted discovery and biosynthesis of novel natural products from Kutzneria.

Genome-Wide Identification of BES1 Gene Family in Six Cucurbitaceae Species and Its Expression Analysis in Cucurbita moschata.

The BES1 (BRI1-EMSSUPPRESSOR1) gene family play a vital role in the BR (brassinosteroid) signaling pathway, which is involved in the growth and development, biotic, abiotic, and hormone stress response in many plants. However, there are few reports of BES1 in Cucurbita moschata. In this study, 50 BES1 genes were identified in six Cucurbitaceae species by genome-wide analysis, which could be classified into 3 groups according to their gene structural features and motif compositions, and 13 CmoBES1 genes in Cucurbita moschata were mapped on 10 chromosomes. Quantitative real-time PCR analysis showed that the CmoBES1 genes displayed differential expression under different abiotic stress and hormone treatments. Subcellular localization showed that the most of CmoBES1 proteins localized in nucleus and cytoplasm, and transactivation assay indicated 9 CmoBES1 proteins played roles as transcription factors. Our analysis of BES1s diversity, localization, and expression in Curcubitaceae contributes to the better understanding of the essential roles of these transcription factors in plants.

Control of lateral root initiation by DA3 in Arabidopsis.

Lateral root (LR) initiation is controlled by the pericycle and the neighboring endodermis in Arabidopsis. Here, we demonstrate that UBIQUITIN-SPECIFIC PROTEASE14/DA3 regulates LR initiation by modulating auxin signaling in the pericycle and endodermis. DA3 negatively affects the mRNA and protein levels of AUXIN RESPONSE FACTOR7 (ARF7) and ARF19 in the pericycle and endodermis but positively regulates the protein stability of SHORT HYPOCOTYL 2 (SHY2/IAA3), an auxin signaling repressor, in the endodermis. We show that DA3 interacts with ARF7 and ARF19, inhibiting their binding to the locus of LATERAL ORGAN BOUNDARY DOMAIN16 (LBD16) to repress its expression in the pericycle. SHY2 also interacts with ARF7 and ARF19 in the endodermis and enhances the DA3 repressive effect on ARF7 and ARF19, thus modulating LBD16 expression in the pericycle. Overall, our findings show that DA3 acts with SHY2, ARF7, and ARF19 to coordinate auxin signaling in the pericycle and endodermis to control LR initiation in Arabidopsis.

Metatranscriptomes reveal the diverse responses of Thaumarchaeota ecotypes to environmental variations in the northern slope of the South China Sea.

Thaumarchaeota are among the most abundant prokaryotes in the ocean, playing important roles in carbon and nitrogen cycling. Marine Thaumarchaeota ecotypes exhibit depth-related diversification and seasonal changes. However, transcriptomic activities concerning niche partitioning among thaumarchaeal ecotypes remain unclear. Here, we examined the variations in the distribution and transcriptomic activity of marine Thaumarchaeota ecotypes. Three primary ecotypes were identified: a Nitrosopumilus-like clade; a Nitrosopelagicus-like water column A (WCA) clade, thriving in epipelagic water; and a water column B (WCB) clade, dominant in deep water. Depth-related partitioning of the three ecotypes and the seasonal variability of the WCA and WCB ecotypes were observed. Nutrient concentrations, chlorophyll α and salinity were the primary environmental factors. The relative abundance of the WCA ecotype and its transcript abundance of amoA gene were positively correlated with chlorophyll α and salinity, while the WCB ecotype was positively correlated with nitrate and phosphate. Based on high-quality metagenome-assembled genomes, transcriptomic analysis revealed that the three ecotypes exhibited various co-occurring expression patterns of the elemental cycling genes in the nitrogen, carbon, phosphorus, and sulfur cycles. Our results provide transcriptomic evidence of the niche differentiation of marine Thaumarchaeota ecotypes, highlighting the diverse roles of ecotypes and WCA subclades in biogeochemical cycles.

Effect of load training on physical fitness in running athletes / Efeito do treinamento de corrida com carga sobre a aptidão física em atletas de corrida / Efecto del entrenamiento de carrera con carga sobre la aptitud física en corredores

ABSTRACT Introduction: Cardiopulmonary capacity and sports endurance are very important for running athletes. Objective: Study whether running with load training can improve physical fitness, focusing on running athletes' cardiopulmonary capacity and exercise endurance. Methods: 36 professional athletes were selected. One group was trained with normal running and the other group was trained with running with a weight load. Results: In the weight-bearing training group, FVC went from 5.13 ± 0.20 to 5.68 ± 1.25, FEV1 went from 4.38 ± 0.33 to 4.56 ± 0.35, PEF went from 8.27 ± 0.98 to 8.88 ± 1.02, ERV went from 1.44 ± 0.37 to 1.68 ± 0.34, IVC went from 4.91 ± 0.45 to 5.28 ± 1.46, VT went from 1.10 ± 0.25 to 1.42 ± 1.26, systolic blood pressure varied from 115.16 ± 8.18 to 117.02 ± 5.47, diastolic blood pressure varied from 78.58 ± 8.97 78.16 ± 7.42, BPM varied from 73.42 ± 9.27 to 73.52 ± 9.02, serum lactic acid was from 1.36 ± 0.28 to 1.31 ± 0.27, and serum creatine kinase was from 21.85 ± 59.02 to 208.11 ± 49.20. Conclusion: Load running training positively impacts athletes' physical fitness and may be added to improve athletes' cardiorespiratory capacity and exercise endurance. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: A capacidade cardiopulmonar e a resistência esportiva são muito importantes para os atletas de corrida. Objetivo: Estudar se o treinamento de corrida com carga pode melhorar a aptidão física, com enfoque na capacidade cardiopulmonar e a resistência ao exercício dos atletas de corrida. Métodos: Foram selecionados 36 atletas profissionais. Um grupo foi treinado com corrida normal e o outro grupo foi treinado com corrida com carga de peso. Resultados: No grupo de treinamento com rolamentos de peso, FVC passou de 5,13 ± 0.20 para 5,68 ± 1,25, FEV1 passou de 4,38 ± 0,33 para 4,56 ± 0,35, PEF passou de 8,27 ± 0,98 para 8,88 ± 1,02, ERV passou de 1,44 ± 0,37 para 1,68 ± 0,3431, IVC passou de 4,91 ± 0,45 para 5,28 ± 1,46, VT passou de 1,10 ± 0,25 para 1,42 ± 1,26, pressão arterial sistólica variou de 115,16 ± 8,18 para 117,02 ± 5,47, pressão arterial diastólica variou de 78,58 ± 8,97 78,16 ± 7,42, BPM variou de 73,42 ± 9,27 para 73,52 ± 9,02, o valor de ácido lático sanguíneo foi de 1,36 ± 0,28 para 1,31 ± 0,27, e a creatina quinase sérica foi de 219,85 ± 59,02 para 208,11 ± 49,20. Conclusão: O treinamento de corrida com carga impacta positivamente a aptidão física dos atletas, podendo ser acrescido para melhorar a capacidade cardiorrespiratória e a resistência ao exercício dos atletas. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: La capacidad cardiopulmonar y la resistencia al deporte son muy importantes para los atletas que corren. Objetivo: Estudiar si correr con entrenamiento de carga puede mejorar la forma física, centrándose en la capacidad cardiopulmonar y la resistencia al ejercicio en atletas corredores. Métodos: Se seleccionaron 36 atletas profesionales. Un grupo fue entrenado con carrera normal y el otro con carrera con carga de peso. Resultados: En el grupo de entrenamiento con carga de peso, la FVC pasó de 5,13 ± 0,20 a 5,68 ± 1,25, el FEV1 pasó de 4,38 ± 0,33 a 4,56 ± 0,35, el PEF pasó de 8,27 ± 0. 98 a 8,88 ± 1,02, ERV pasó de 1,44 ± 0,37 a 1,68 ± 0,34, IVC pasó de 4,91 ± 0,45 a 5,28 ± 1,46, VT pasó de 1,10 ± 0,25 a 1,42 ± 1. 2645, la presión arterial sistólica varió de 115,16 ± 8,18 a 117,021 ± 5,47, PPM varió de 78,58 ± 8,97 a 78,16 ± 7,42, las pulsaciones por minuto variaron de 73,42 ± 9,27 a 73,52 ± 9,02, el valor de ácido láctico en sangre fue de 1,36 ± 0,28 a 1,31 ± 0,27, y la creatina quinasa sérica fue de 219,85 ± 59,02 a 208,11 ± 49,20. Conclusión: El entrenamiento de carrera con carga influye positivamente en la forma física de los atletas, y puede añadirse para mejorar la capacidad cardiorrespiratoria y la resistencia al ejercicio de los atletas. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

Sphingomicrobium nitratireducens sp. nov., isolated from a tidal flat in Guangxi.

An aerobic, yellow-pigmented and Gram-stain-negative strain, designated as O-35 T, was isolated from a tidal flat sediment collected in Dangjiang Town, the southern China. Colonies of strain O-35 T were circular with 0.5-1.0 mm in diameter, convex and smooth. Cells of strain O-35 T were coccoid-shaped, non-spore forming, non-motile and the strain could reduce nitrate. Growth of strain O-35 T was observed at 15-40 °C (optimum 30 °C), at pH 6.0-9.5 (optimum 7.5-8.0) and in 0.5-5.0% NaCl (optimum 2%, w/v). Strain O-35 T showed 16S rRNA gene sequence identities of 97.3-97.5% with Sphingomicrobium lutaoense CC-TBT-3 T and Sphingomicrobium aestuariivivum AH-M8T, higher than the rest of Sphingomicrobium type strains. Phylogenetic trees based on the 16S rRNA gene and the core-genome sequences demonstrated that strain O-35 T was affiliated within the genus Sphingomicrobium. Overall genome relatedness index calculations revealed that strain O-35 T had < 75.8% of average nucleotide identity and < 19.2% of digital DNA-DNA hybridization values with Sphingomicrobium type strains. The sole isoprenoid quinone was ubiquinone-10. The major fatty acids (> 10%) were summed feature 8, summed feature 3, C16:0 and C18:1 2-OH. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, sphingoglycolipid, two unidentified glycolipids, one unidentified lipid and one unidentified phospholipid. On the basis of the phenotypic, chemotaxonomic and genomic properties, strain O-35 T represents a novel species in the genus Sphingomicrobium, for which the name Sphingomicrobium nitratireducens sp. nov. is proposed. The type strain is O-35 T (= KCTC 92308 T = MCCC 1K07589T).

Metagenomic Features Characterized with Microbial Iron Oxidoreduction and Mineral Interaction in Southwest Indian Ridge.

The Southwest Indian Ridge (SWIR) is one of the typical representatives of deep-sea ultraslow-spreading ridges, and has increasingly become a hot spot of studying subsurface geological activities and deep-sea mining management. However, the understanding of microbial activities is still limited on active hydrothermal vent chimneys in SWIR. In this study, samples from an active black smoker and a diffuse vent located in the Longqi hydrothermal region were collected for deep metagenomic sequencing, which yielded approximately 290 GB clean data and 295 mid-to-high-quality metagenome-assembled genomes (MAGs). Sulfur oxidation conducted by a variety of Gammaproteobacteria, Alphaproteobacteria, and Campylobacterota was presumed to be the major energy source for chemosynthesis in Longqi hydrothermal vents. Diverse iron-related microorganisms were recovered, including iron-oxidizing Zetaproteobacteria, iron-reducing Deferrisoma, and magnetotactic bacterium. Twenty-two bacterial MAGs from 12 uncultured phyla harbored iron oxidase Cyc2 homologs and enzymes for organic carbon degradation, indicated novel chemolithoheterotrophic iron-oxidizing bacteria that affected iron biogeochemistry in hydrothermal vents. Meanwhile, potential interactions between microbial communities and chimney minerals were emphasized as enriched metabolic potential of siderophore transportation, and extracellular electron transfer functioned by multi-heme proteins was discovered. Composition of chimney minerals probably affected microbial iron metabolic potential, as pyrrhotite might provide more available iron for microbial communities. Collectively, this study provides novel insights into microbial activities and potential mineral-microorganism interactions in hydrothermal vents. IMPORTANCE Microbial activities and interactions with minerals and venting fluid in active hydrothermal vents remain unclear in the ultraslow-spreading SWIR (Southwest Indian Ridge). Understanding about how minerals influence microbial metabolism is currently limited given the obstacles in cultivating microorganisms with sulfur or iron oxidoreduction functions. Here, comprehensive descriptions on microbial composition and metabolic profile on 2 hydrothermal vents in SWIR were obtained based on cultivation-free metagenome sequencing. In particular, autotrophic sulfur oxidation supported by minerals was presumed, emphasizing the role of chimney minerals in supporting chemosynthesis. Presence of novel heterotrophic iron-oxidizing bacteria was also indicated, suggesting overlooked biogeochemical pathways directed by microorganisms that connected sulfide mineral dissolution and organic carbon degradation in hydrothermal vents. Our findings offer novel insights into microbial function and biotic interactions on minerals in ultraslow-spreading ridges.