Reference genomes are essential for metagenomic analyses and functional characterization of the human gut microbiota. We present the Culturable Genome Reference (CGR), a collection of 1,520 ...nonredundant, high-quality draft genomes generated from >6,000 bacteria cultivated from fecal samples of healthy humans. Of the 1,520 genomes, which were chosen to cover all major bacterial phyla and genera in the human gut, 264 are not represented in existing reference genome catalogs. We show that this increase in the number of reference bacterial genomes improves the rate of mapping metagenomic sequencing reads from 50% to >70%, enabling higher-resolution descriptions of the human gut microbiome. We use the CGR genomes to annotate functions of 338 bacterial species, showing the utility of this resource for functional studies. We also carry out a pan-genome analysis of 38 important human gut species, which reveals the diversity and specificity of functional enrichment between their core and dispensable genomes.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We carried out metagenomic shotgun sequencing and a metagenome-wide association study (MGWAS) of fecal, dental and salivary samples from a cohort of individuals with rheumatoid arthritis (RA) and ...healthy controls. Concordance was observed between the gut and oral microbiomes, suggesting overlap in the abundance and function of species at different body sites. Dysbiosis was detected in the gut and oral microbiomes of RA patients, but it was partially resolved after RA treatment. Alterations in the gut, dental or saliva microbiome distinguished individuals with RA from healthy controls, were correlated with clinical measures and could be used to stratify individuals on the basis of their response to therapy. In particular, Haemophilus spp. were depleted in individuals with RA at all three sites and negatively correlated with levels of serum autoantibodies, whereas Lactobacillus salivarius was over-represented in individuals with RA at all three sites and was present in increased amounts in cases of very active RA. Functionally, the redox environment, transport and metabolism of iron, sulfur, zinc and arginine were altered in the microbiota of individuals with RA. Molecular mimicry of human antigens related to RA was also detectable. Our results establish specific alterations in the gut and oral microbiomes in individuals with RA and suggest potential ways of using microbiome composition for prognosis and diagnosis.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, UILJ, UKNU, UL, UM, UPUK
Abstract
Exploiting a pure culture strategy to investigate the composition of the human gut microbiota, two novel anaerobes, designated strains AF52-21
T
and CM04-06
T
, were isolated from faeces of ...two healthy Chinese donors and characterized using a polyphasic approach. The two strains were observed to be gram-negative, non-motile, and rod-shaped. Both strains grew optimally at 37 °C and pH 7.0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the two strains clustered with species of the genus
Faecalibacterium
and were most closely related to
Faecalibacterium prausnitzii
ATCC 27768
T
with sequence similarity of 97.18% and 96.87%, respectively. The two isolates shared a 16S rRNA gene sequence identity of 98.69%. Draft genome sequencing was performed for strains AF52-21
T
and CM04-06
T
, generating genome sizes of 2.85 Mbp and 3.01 Mbp. The calculated average nucleotide identity values between the genomes of the strains AF52-21
T
and CM04-06
T
compared to
Faecalibacterium prausnitzii
ATCC 27768
T
were 83.20% and 82.54%, respectively, and 90.09% when comparing AF52-21
T
and CM04-06
T
. Both values were below the previously proposed species threshold (95–96%), supporting their recognition as novel species in the genus
Faecalibacterium
. The genomic DNA G + C contents of strains AF52-21
T
and CM04-06
T
calculated from genome sequences were 57.77 mol% and 57.51 mol%, respectively. Based on the phenotypic, chemotaxonomic and phylogenetic characteristics, we conclude that both strains represent two new
Faecalibacterium
species, for which the names
Faecalibacterium butyricigenerans
sp. nov. (type strain AF52-21
T
= CGMCC 1.5206
T
= DSM 103434
T
) and
Faecalibacterium longum
sp. nov. (type strain CM04-06
T
= CGMCC 1.5208
T
= DSM 103432
T
) are proposed.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Heterostructure composites have gained prominence for potential energy storage applications. Here, we synthesized a nanorod-like core–shell heterostructure supercapacitor electrode material, denoted ...as Sb
2
S
3
@MoS
2
/C, using a facile hydrothermal method. Impressively, this Sb
2
S
3
/MoS
2
/C heterostructure demonstrated superior electrochemical performance compared to pure Sb
2
S
3
nanorods, exhibiting a high capacitance of 226 F g
−1
at 1 A g
−1
. Remarkably, this capacity stability remained at 83.5% even after 10,000 cycles at current densities up to 10 A g
−1
. This enhanced performance arises from the core–shell structure, allowing increased active sites. The outer shell effectively prevents the bulk deformation of Sb
2
S
3
, while the inner core hinders the collapse of lamellar MoS
2
during charge–discharge process. As a result, this core–shell configuration enables a more rapid ion transport and maintains a stable structure, thereby contributing to the enhanced electrochemical performance.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Assessment and characterization of gut microbiota has become a major research area in human disease, including type 2 diabetes, the most prevalent endocrine disease worldwide. To carry out analysis ...on gut microbial content in patients with type 2 diabetes, we developed a protocol for a metagenome-wide association study (MGWAS) and undertook a two-stage MGWAS based on deep shotgun sequencing of the gut microbial DNA from 345 Chinese individuals. We identified and validated approximately 60,000 type-2-diabetes-associated markers and established the concept of a metagenomic linkage group, enabling taxonomic species-level analyses. MGWAS analysis showed that patients with type 2 diabetes were characterized by a moderate degree of gut microbial dysbiosis, a decrease in the abundance of some universal butyrate-producing bacteria and an increase in various opportunistic pathogens, as well as an enrichment of other microbial functions conferring sulphate reduction and oxidative stress resistance. An analysis of 23 additional individuals demonstrated that these gut microbial markers might be useful for classifying type 2 diabetes.
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DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Plasma anodizing is a novel promising process to fabricate corrosion-resistant protective films on metal matrix composites. The corrosion-resistant films were prepared by plasma anodizing on SiC ...reinforced aluminum matrix composite. The morphology and microstructure of films were analyzed by scanning electron microscopy. Specifically, the morphology of residual SiC reinforcement particles in the film was observed. It is found that the most SiC reinforcement particles have been molten to become silicon oxide, but a few tiny SiC particles still remain in the film close to the composite/film interface. This interface is irregular due to the hindering effect of SiC particles on the film growth. Morphology and distribution of residual SiC particles in film provide direct evidence to identify the local melt occurs in the interior of plasma anodizing film even near the composite/film interface. A model of film growth by plasma anodizing on metal matrix composites was proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract
In order to adapt to the development of lightweight equipment, and further improve the wear resistance of ZL109 aluminum alloy, the influence of nickel-coated carbon nanotubes as an ...electrolyte additive on the preparation and wear resistance of microarc oxidation ceramic coatings on ZL109 aluminum alloy surface was investigated. In this work, 0.4 g/L, 0.8 g/L, 1.2 g/L, 1.6 g/L, and 2 g/L nickel-coated carbon nanotubes were added to the electrolyte respectively. The microarc oxidation ceramic coatings were prepared under bipolar pulse constant pressure mode, which were analyzed from the aspects of morphology, chemical composition, and wear resistance property. The results show that the nickel-coated carbon nanotubes possess a great influence on ceramic coatings. The morphology of ceramic coatings was significantly changed. In this work, the coating prepared by 1.2 g/L nickel-coated carbon nanotubes exhibits excellent wear resistance property.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
•Prepare hardened layers on steel by plasma electrolytic borocarburizing (PEB/C).•Characterize morphology, microstructure and hardness of PEB/C steel.•Evaluate corrosion resistance of PEB/C steel by ...polarization and EIS.•The PEB/C treatment greatly improved wear resistance of steel.
The Q235 low-carbon steel was hardened by plasma electrolytic borocarburizing (PEB/C) process. Surface borocarburizing was carried out in 15% borax aqueous solution with glycerin additive at 290V under different treating time. The hardened layers on Q235 low-carbon steel were analyzed by SEM, XRD and microhardness test. Corrosion behavior of PEB/C layers was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy. Their wear performance under dry sliding was measured using a pin-disc friction and wear tester. It showed that the PEB/C layer consisted of a boride (Fe2B) layer and a transition layer. The thickness of boride layer increased with the borocarburizing time and reached 8μm after 30min treatment. The highest microhardness of the boride layer was up to 1450HV, which was much higher than that of bare Q235 steel with about 170HV. The PEB/C treatment slightly improved corrosion resistance of Q235 low-carbon steel and the corrosion resistance of the PEB/C treated steel increased with increasing the borocarburizing time, which was ascribed to the formation of boride in the hardened layer. After the PEB/C treatment, the friction coefficient of Q235 low-carbon steel decreased from 0.63 to 0.16. The lowest wear rate of hardened layer under dry sliding against ZrO2 ball was about 1.438×10−6mm3/Nm, which was only 1/12 of the bare Q235 steel. The PEB/C treatment is an effective method to improve the wear resistance of carbon steel.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A thin protective film on Zr–1Nb alloy was fabricated by AC microarc oxidation (MAO) in phosphate electrolyte. The morphology, microstructure and phase constituents of MAO films under different ...discharge voltages were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. Their surface roughness and microhardness were measured. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate corrosion behaviors of films. The equivalent circuits of EIS plots for bare Zr–1Nb alloy and MAO films were proposed. It was found that all of films at different discharge voltages consisted of the monoclinic ZrO2 and tetragonal ZrO2 phases, but the content of monoclinic ZrO2 was much higher than that of tetragonal ZrO2 phase. Microhardness of MAO films is over 570HV, which is higher than that of Zr–1Nb alloy substrate with 245HV. The film fabricated in higher voltage shows lower corrosion current density and higher impedance, which displays better corrosion resistance. The EIS results identify that the inner compact layer of MAO films plays a key role in improving the corrosion resistance of Zr–1Nb alloy.
► Prepare protective film on Zr alloy by AC microarc oxidation in phosphate solution. ► Effects of voltage on microstructure and properties of MAO films were studied. ► The film below 15μm thick is compact. ► The MAO films have better corrosion resistance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Thick ceramic coatings were prepared on zirconium alloy by plasma electrolytic oxidation (PEO) in silicate electrolyte. Their microstructure and phase constituent were analyzed. The micromechanical ...properties of a thick coating are measured by nanoindentation method. The electrochemical corrosion behaviors of the coatings were evaluated by potentiodynamic polarization. The coating consists of the monoclinic ZrO
2 and tetragonal ZrO
2, but the tetragonal ZrO
2 content is much lower than the monoclinic ZrO
2 content. In the inner layer coating, the nanohardness and elastic modulus are much higher than that of the Zr substrate, and their maximum values reach 7.4
GPa and 170
GPa, respectively. However, the elastic modulus of the coating is lower than that of Zr substrate when the distance is far from the coating/Zr interface. After PEO treatment, the corrosion potential of zirconium alloy moves to a more positive potential, and the corrosion current density reduces several orders of magnitude. However, the corrosion current density increases again while the coating is very thick. PEO is an effective method to improve corrosion resistance of zirconium, especially for pitting attack.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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