Structural and molecular basis for urea recognition by Prochlorococcus.

Nitrogen (N) is an essential element for microbial growth and metabolism. The growth and reproduction of microorganisms in more than 75% of areas of the ocean are limited by N. Prochlorococcus is numerically the most abundant photosynthetic organism on the planet. Urea is an important and efficient N source for Prochlorococcus. However, how Prochlorococcus recognizes and absorbs urea still remains unclear. Prochlorococcus marinus MIT 9313, a typical Cyanobacteria, contains an ABC-type transporter, UrtABCDE, which may account for the transport of urea. Here, we heterologously expressed and purified UrtA, the substrate-binding protein of UrtABCDE, detected its binding affinity toward urea, and further determined the crystal structure of the UrtA/urea complex. Molecular dynamics simulations indicated that UrtA can alternate between "open" and "closed" states for urea binding. Based on structural and biochemical analyses, the molecular mechanism for urea recognition and binding was proposed. When a urea molecule is bound, UrtA undergoes a state change from open to closed surrounding the urea molecule, and the urea molecule is further stabilized by the hydrogen bonds supported by the conserved residues around it. Moreover, bioinformatics analysis showed that ABC-type urea transporters are widespread in bacteria and probably share similar urea recognition and binding mechanisms as UrtA from P. marinus MIT 9313. Our study provides a better understanding of urea absorption and utilization in marine bacteria.

Metagenomic insights into the dynamic degradation of brown algal polysaccharides by kelp-associated microbiota.

Marine bacteria play important roles in the degradation and cycling of algal polysaccharides. However, the dynamics of epiphytic bacterial communities and their roles in algal polysaccharide degradation during kelp decay are still unclear. Here, we performed metagenomic analyses to investigate the identities and predicted metabolic abilities of epiphytic bacterial communities during the early and late decay stages of the kelp Saccharina japonica. During kelp decay, the dominant epiphytic bacterial communities shifted from Gammaproteobacteria to Verrucomicrobia and Bacteroidetes. In the early decay stage of S. japonica, epiphytic bacteria primarily targeted kelp-derived labile alginate for degradation, among which the gammaproteobacterial Vibrionaceae (particularly Vibrio) and Psychromonadaceae (particularly Psychromonas), abundant in alginate lyases belonging to the polysaccharide lyase (PL) families PL6, PL7, and PL17, were key alginate degraders. More complex fucoidan was preferred to be degraded in the late decay stage of S. japonica by epiphytic bacteria, predominantly from Verrucomicrobia (particularly Lentimonas), Pirellulaceae of Planctomycetes (particularly Rhodopirellula), Pontiellaceae of Kiritimatiellota, and Flavobacteriaceae of Bacteroidetes, which depended on using glycoside hydrolases (GHs) from the GH29, GH95, and GH141 families and sulfatases from the S1_15, S1_16, S1_17, and S1_25 families to depolymerize fucoidan. The pathways for algal polysaccharide degradation in dominant epiphytic bacterial groups were reconstructed based on analyses of metagenome-assembled genomes. This study sheds light on the roles of different epiphytic bacteria in the degradation of brown algal polysaccharides.IMPORTANCEKelps are important primary producers in coastal marine ecosystems. Polysaccharides, as major components of brown algal biomass, constitute a large fraction of organic carbon in the ocean. However, knowledge of the identities and pathways of epiphytic bacteria involved in the degradation process of brown algal polysaccharides during kelp decay is still elusive. Here, based on metagenomic analyses, the succession of epiphytic bacterial communities and their metabolic potential were investigated during the early and late decay stages of Saccharina japonica. Our study revealed a transition in algal polysaccharide-degrading bacteria during kelp decay, shifting from alginate-degrading Gammaproteobacteria to fucoidan-degrading Verrucomicrobia, Planctomycetes, Kiritimatiellota, and Bacteroidetes. A model for the dynamic degradation of algal cell wall polysaccharides, a complex organic carbon, by epiphytic microbiota during kelp decay was proposed. This study deepens our understanding of the role of epiphytic bacteria in marine algal carbon cycling as well as pathogen control in algal culture.

Spartinivicinus marinus sp. nov., isolated from intertidal sediment.

A Gram-stain-negative, aerobic, flagellated, and long rod-shaped bacterium, designated strain SM1973T, was isolated from an intertidal sediment sample collected from the coast of Qingdao, PR China. Strain SM1973T grew at 15-37 °C and with 0-5.5 % NaCl. It reduced nitrate to nitrite and hydrolysed aesculin but did not hydrolyse casein and gelatin. The strain showed the highest 16S rRNA gene sequence similarity (98.2 %) to the type strain of Spartinivicinus ruber. The phylogenetic trees based on the 16S rRNA genes and single-copy orthologous clusters showed that strain SM1973T clustered with S. ruber, forming a separate lineage within the family Zooshikellaceae. The major cellular fatty acids were summed feature 3 (C16 : 1 ω7с and/or C16 : 1 ω6с) and C16 : 0. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The main respiratory quinone was ubiquinone-9. The genomic DNA G+C content of strain SM1973T was 40.4 mol%. Based on the polyphasic evidence presented in this paper, strain SM1973T is considered to represent a novel species within the genus Spartinivicinus, for which the name Spartinivicinus marinus sp. nov. is proposed. The type strain is SM1973T (=MCCC 1K04833T=KCTC 72846T).

Celeribacter litoreus sp. nov., isolated from intertidal sediment.

A Gram-negative, aerobic, non-flagellated and rod-shaped bacterium, strain ASW11-22T, was isolated from an intertidal sediment collected from a coastal area of Qingdao, PR China. The strain grew at 15-40 °C (optimum, 37 °C), at pH 6.0-9.0 (optimum, pH 7.0) and with 0.5-10 % (w/v) NaCl (optimum, 1.0 %). It hydrolysed gelatin and aesculin but did not reduce nitrate to nitrite. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ASW11-22T belonged to the genus Celeribacter, showing the highest sequence similarity to the type strains of Celeribacter halophilus MCCC 1A06432T (98.20 %) and Celeribacter ethanolicus NH195T (97.84 %). The genomic DNA G+C content was 59.1 mol%. The major cellular fatty acid (>10 %) of the strain was summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and its main polar lipids were phosphatidylglycerol and one unidentified aminolipid. The sole respiratory quinone of strain ASW11-22T was ubiquinone-10. On the basis of the polyphasic evidence presented in this paper, strain ASW11-22T represents a novel Celeribacter species, for which the name Celeribacter litoreus sp. nov. is proposed. The type strain is ASW11-22T (=KCTC 82495T=MCCC 1K05584T).

Description of Aureibaculum luteum sp. nov. and Aureibaculum flavum sp. nov. isolated from Antarctic intertidal sediments.

Two Gram-stain-negative, aerobic, non-motile, and rod-shaped bacterial strains, designated SM1352T and A20T, were isolated from intertidal sediments collected from King George Island, Antarctic. They shared 99.8% 16S rRNA gene sequence similarity with each other and had the highest sequence similarity of 98.1% to type strain of Aureibaculum marinum but < 93.4% sequence similarity to those of other known bacterial species. The genomes of strains SM1352T and A20T consisted of 5,108,092 bp and 4,772,071 bp, respectively, with the G + C contents both being 32.0%. They respectively encoded 4360 (including 37 tRNAs and 6 rRNAs) and 4032 (including 36 tRNAs and 5 rRNAs) genes. In the phylogenetic trees based on 16S rRNA gene and single-copy orthologous clusters (OCs), both strains clustered with Aureibaculum marinum and together formed a separate branch within the family Flavobacteriaceae. The ANI and DDH values between the two strains and Aureibaculum marinum BH-SD17T were all below the thresholds for species delineation. The major cellular fatty acids (> 10%) of the two strains included iso-C15:0, iso-C15:1 G, iso-C17:0 3-OH. Their polar lipids predominantly included phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified aminolipid, and two unidentified lipids. Genomic comparison revealed that both strains possessed much more glycoside hydrolases and sulfatase-rich polysaccharide utilization loci (PULs) than Aureibaculum marinum BH-SD17T. Based on the above polyphasic evidences, strains SM1352T and A20T represent two novel species within the genus Aureibaculum, for which the names Aureibaculum luteum sp. nov. and Aureibaculum flavum sp. nov. are proposed. The type strains are SM1352T (= CCTCC AB 2014243 T = JCM 30335 T) and A20T (= CCTCC AB 2020370 T = KCTC 82503 T), respectively.

Reconstruction of Distal Nasal Defects With a Large Postauricular Skin-Fat-Fascia Composite Graft.

BACKGROUND: Composite grafts have previously been reported to achieve a good outcome for nasal defect repair, but composite grafts have greater metabolic needs than simple skin. Therefore, the traditionally recommended size of a composite graft for nasal reconstruction is less than 1.5 cm in diameter. However, the distal nose is generally well supplied with blood vessels, which might support the use of larger composite grafts in such a highly vascularized recipient site. The aim of the article is to investigate whether a large skin-fat-fascia composite graft (larger than 2.0 cm) is viable for the repair of partial-thickness nasal defects. METHODS: From October 2017 to December 2019, 13 patients with partial-thickness nasal defects underwent nasal reconstruction using a large postauricular skin-fat-fascia composite graft. Cases were followed up for 3 to 14 months postoperatively. The aesthetic outcome was evaluated in comparison with preoperative digital images. RESULTS: Skin-fat-fascia composite grafts survived without graft necrosis, dermal fibrosis, or skin contraction in all cases. Favorable aesthetic outcomes were obtained in all patients, and no further revision surgery was need. CONCLUSIONS: A postauricular composite graft larger than 2.0 cm is a safe and effective reconstruction approach for partial-thickness nasal defects. This technique offers significant advantages in terms of no additional facial scar, no visible asymmetry on the face, no additional surgery for revision, and with mild scar in the donor site of the postauricular region.

Identification of differentially expressed circular RNAs in keloid and normal skin tissue by high-throughput sequencing.

Keloid is a kind of pathological skin scar with unclear molecular pathology. Circular RNAs (circRNAs) are involved in the occurrence and development of many diseases; however, their relationship with keloid is not well understood. To investigate the involvement of dysregulated circRNAs in keloid. Thirty-seven keloids and 37 normal skin tissues were collected, and the changes of circRNAs, microRNAs (miRNAs) and mRNAs in 3 keloids and 3 normal samples by high-throughput sequencing were detected first. Based on the circRNA-miRNA-mRNA interaction network construction, gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis combining several signaling pathways associated with keloid formation and progression, the circRNAs required further verification were screened out. The expression levels of the selected circRNAs were verified in 37 keloids and 37 normal skin tissues using quantitative real-time polymerase chain reaction (QPCR). The interaction of candidate circRNA and its predicted binding miRNA was tested by dual-luciferase reporter gene experiment. Compared with normal controls, there was an average of 120 and 12 circRNAs, 44 and 63 miRNAs, 656 and 156 mRNAs were upregulated and downregulated, respectively, in keloids. According to the analysis of bioinformation, six circRNAs were picked out. The QPCR validation results of two upregulated circRNAs (hsa_circ_0001320 and circCOL5A1) were consistent with previous sequencing results. The interaction between hsa_circ_0001320 and miR-574-5p was confirmed. This study makes it clear that the abnormal expression of circRNAs may be related to the pathological process of keloid.

Marinifaba aquimaris gen. nov., sp. nov., a novel chitin-degrading gammaproteobacterium in the family Alteromonadaceae isolated from seawater of the Mariana Trench.

A novel Gram-negative, rod-shaped, aerobic, oxidase-positive and catalase-negative bacterium, designated strain SM1970T, was isolated from a seawater sample collected from the Mariana Trench. Strain SM1970T grew at 15-37 oC and with 1-5% (w/v) NaCl. It hydrolyzed colloidal chitin, agar and casein but did not reduce nitrate to nitrite. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain SM1970T formed a distinct lineage close to the genus Catenovulum within the family Alteromonadaceae, sharing the highest sequence similarity (93.6%) with type strain of Catenovulum maritimum but < 93.0% sequence similarity with those of other known species in the class Gammaproteobacteria. The major fatty acids of strain SM1970T 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 major polar lipids of the strain included phosphatidylethanolamine and phosphatidylglycerol and its main respiratory quinone was ubiquinone 8. The draft genome of strain SM1970T consisted of 77 scaffolds and was 4,172,146 bp in length, containing a complete set of genes for chitin degradation. The average amino acid identity (AAI) values between SM1970T and type strains of known Catenovulum species were 56.6-57.1% while the percentage of conserved proteins (POCP) values between them were 28.5-31.5%. The genomic DNA G + C content of strain SM1970T was 40.1 mol%. On the basis of the polyphasic analysis, strain SM1970T is considered to represent a novel species in a novel genus of the family Alteromonadaceae, for which the name Marinifaba aquimaris is proposed with the type strain being SM1970T (= MCCC 1K04323T = KCTC 72844T).

Tritonibacter aquimaris sp. nov. and Tritonibacter litoralis sp. nov., two novel members of the Roseobacter group isolated from coastal seawater.

Two Gram-stain-negative bacterial strains, SM1969T and SM1979T, were isolated from coastal surface seawater of Qingdao, China. They were taxonomically characterized by the phylogenetic, genomic, chemotaxonomic and phenotypic analyses. The two strains shared 97.0% 16S rRNA gene sequence similarity with each other and the highest similarity (96.8-97.5%) with type strains of six species in the genera Shimia, Tritonibacter and Tropicibacter in the Roseobacter group of the family Rhodobacteraceae. In the phylogenetic tree based on single-copy orthologous clusters (OCs), both strains clustered with known species of the genus Tritonibacter and together formed a separate branch adjacent to Tritonibacter ulvae. Although sharing many chemotaxonomic and phenotypic characteristics, the two strains could be differentiated from each other and closely related species by numerous traits. Particularly, strain SM1969T was found to have a DMSP lyase coding gene dddW in its genome and have the ability to produce DMS from DMSP while strain SM1979T was not. The average nucleotide identity and in silico DNA-DNA hybridization values between strains SM1969T and SM1979T and type strains of closely related species were all below the thresholds to discriminate bacterial species, demonstrating that they constitute two new species in the genus Tritonibacter. The names Tritonibacter aquimaris sp. nov. and Tritonibacter litoralis sp. nov. are proposed for the two new species, with type strains being SM1969T (= MCCC 1K04320T = KCTC 72843T) and SM1979T (= MCCC 1K04321T = KCTC 72842T), respectively.

Modified Maximal Levator Palpebrae Superioris Shortening in Correcting Congenital Severe Ptosis in Children.

OBJECTIVE: This study aims to evaluate the clinical effect of modified maximal levator palpebrae superioris shortening method for severe congenital ptosis. METHODS: A retrospective case series was performed including 66 eyes from 62 patients who underwent modified maximal levator palpebrae superioris shortening surgery to treat severe congenital ptosis between February 2015 and November 2018. Preoperative and postoperative margin reflex distance 1 and levator muscle function were recorded. The surgical results were graded as good, satisfied, and poor for functional and cosmetic improvement of the eyelids, and the incidence of complications was also documented. RESULTS: The mean patient age at the time of surgery was 4.6 ± 1.8 years (2-9 years), and the mean follow-up time was 36.3 ± 14.1 (12-55 months). A mean significant improvement in margin reflex distance 1 and levator function after operation was noted (P < 0.01). The eyelid height and symmetry were satisfied in 59 patients, with success rate of 95.2%. For the patients in the levator function (≤2 mm) group, the success rate was 87.5%. Moreover, the levator function (≤2 mm) group had a higher rate of poor results than levator function (2-4 mm) group (12.5% vs 2.2%). Overcorrection (6.5%) and eyelid fold deformity (11.3%) were the most frequent postoperative complications. CONCLUSION: Modified maximal levator palpebrae superioris shortening was effective and endurable in the treatment of severe congenital ptosis with poor levator function, including in patients whose levator function was less than 2 mm.

Antarcticimicrobium sediminis gen. nov., sp. nov., isolated from Antarctic intertidal sediment, transfer of Ruegeria lutea to Antarcticimicrobium gen. nov. as Antarcticimicrobium luteum comb. nov.

A Gram-stain-negative, aerobic, non-flagellated and rod- or ovoid-shaped bacterium, designated as strain S4J41T, was isolated from Antarctic intertidal sediment. The isolate grew at 0-37 °C and with 0.5-10 % (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed Tween 80 and gelatin. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain S4J41T constituted a distinct phylogenetic line within the family Rhodobacteraceae and was closely related with some species in the genera Ruegeria, Phaeobacter, Pseudopuniceibacterium, Sulfitobacter, Puniceibacterium and Poseidonocella with 98.6-95.7 % 16S rRNA gene sequence similarities. The major cellular fatty acids were C16 : 0, summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C18 : 0 and the major polar lipids were phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, phosphatidylethanolamine and one unidentified aminolipid. The sole respiratory quinone was Q-10. The genomic DNA G+C content of strain S4J41T was 60.3 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data obtained in this study, strain S4J41T is considered to represent a novel species in a new genus within the family Rhodobacteraceae, for which the name Antarcticimicrobium sediminis gen. nov., sp. nov. is proposed. The type strain is S4J41T (=MCCC 1K03508T=KCTC 62793T). Moreover, the transfer of Ruegeria lutea Kim et al. 2019 to Antarcticimicrobium gen. nov. as Antarcticimicrobium luteum comb. nov. (type strain 318-1T=JCM 30927T=KCTC 72105T) is also proposed.

Fluviibacterium aquatile gen. nov., sp. nov., isolated from estuary sediment.

A Gram-negative, aerobic, non-flagellated and ovoid- or rod-shaped bacterium, designated strain SM1902T, was isolated from the sediment sampled at the Jia River estuary, Yantai, PR China. The strain grew at 10-37 °C (optimum, 25-30 °C), pH 6.0-10.0 (pH 7.0) and with 0.5-13.0 % (w/v) NaCl (2.5%). It reduced nitrate to nitrite, but did not produce bacteriochlorophyll a. The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1902T constituted a separated lineage within the family Rhodobacteraceae and was closely related to Meridianimarinicoccus roseus TG-679T and Phycocomes zhengii LMIT002T with 96.1 and 94.3 % 16S rRNA gene sequence similarities, respectively. The predominant cellular fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid and an unidentified lipid. The sole respiratory quinone was ubiquinone-10. The in silico DNA-DNA hybridization values between strain SM1902T and Meridianimarinicoccus roseus TG-679T and Phycocomes zhengii LMIT002T were 19.6 and 19.5 %, respectively; and the average nucleotide identity values between them were 76.1 and 74.2 %, respectively. The genomic DNA G+C content of strain SM1902T was 58.2 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data obtained in this study, strain SM1902T is considered to represent a novel species in a new genus within the family Rhodobacteraceae, for which the name Fluviibacterium aquatile gen. nov., sp. nov. is proposed. The type strain is SM1902T (=KCTC 72045T=MCCC 1K03596T=CCTCC AB 2018346T).

Marinomonas algicola sp. nov. and Marinomonas colpomeniae sp. nov., isolated from marine macroalgae.

Two Gram-stain-negative, aerobic, rod-shaped bacteria, polar flagellated, designated strains SM2066T and SM1966T, were respectively isolated from the surfaces of Colpomenia sinuosa and Ulva pertusa macroalgae collected off the coastal areas of Rongcheng, PR China. Strain SM2066T grew at 8-37 °C and with 0.5-7.0 % (w/v) NaCl, while strain SM1966T grew at 5-30 °C and with 0.5-8.5% (w/v) NaCl. Both of them reduced nitrate to nitrite and required Na+ for growth but neither of them hydrolysed starch and DNA. Phylogenetic analysis based on 16S rRNA gene and single-copy orthologous cluster sequences revealed that both strains SM2066T and SM1966T were affiliated with the genus Marinomonas but formed distinct phylogenetic branches from known Marinomonas species, respectively sharing the highest 16S rRNA gene sequence similarities with type strains of Marinomonas ushuaiensis (97.9 %) and Marinomonas blandensis (96.7 %). The digital DNA-DNA hybridization and average nucleotide identity values between strains SM2066T and SM1966T and type strains of closely related Marinomonas species were all below 22.9 and 79.9 mol%, respectively. The major fatty acids of the two strains were summed feature 3 (C16 : 1 ω6c/C16 : 1 ω7c), summed feature 8 (C18 : 1 ω7c) and C16 : 0, with their predominant polar lipids being phosphatidylethanolamine and phosphatidylglycerol, and their sole respiratory quinone being Q-8. The genomic DNA G+C contents of strains SM2066T and SM1966T determined from genomic sequences were 40.3 and 41.6 mol%, respectively. On the basis of the polyphasic evidence presented in this study, strains SM2066T and SM1966T are considered to represent two novel species within the genus Marinomonas, for which the names Marinomonas colpomeniae sp. nov. and Marinomonas algicola sp. nov. are proposed. The type strains are SM2066T (=MCCC 1K04390T= KCTC 82372T) and SM1966T (=MCCC 1K04387T= KCTC 72848T), respectively.

Application of avidin-biotin technology to improve cell adhesion on nanofibrous matrices.

BACKGROUND: Electrospinning is an easy and effective technique to produce submicron fibers possessing a range of attractive characteristics such as interconnected porous structures similar to natural ECM and good resilience to movement. Rapid and efficient cell attachment to nanofibrous matrices is a necessary prerequisite in tissue engineering. Thus, the aim of this study is to evaluate poly(ε-caprolactone-co-lactide)/Pluronic (PLCL/Pluronic) nanofibrous matrices with avidin-biotin technology for improving cell adhesion for the first time. RESULTS: PLCL/Pluronic nanofibers had relatively homogeneous fibers and interconnected porous structures. Pluronic significantly modified the hydrophilicity of nanofibrous matrices and PLCL/Pluronic nanofibrous matrices had better performance on maintaining cell proliferation. Avidin-biotin technology had no negative effect on the hydrophilic property, mechanical property and cell proliferation. Meanwhile, the attachment and spreading of adipose-derived stem cells (ADSCs) onto PLCL/Pluronic nanofibrous matrices with avidin-biotin technology was promoted obviously. CONCLUSIONS: PLCL/Pluronic nanofibrous matrices inheriting the excellent characteristics of both PLCL and Pluronic have the better cell adhesion ability through avidin-biotin technology, implying a promising application in skin care, tissue regeneration and other related area.

Quantitative Framework Fabrication with Autogenous Costal Cartilage in Microtia Reconstruction.

Hearing improvement is another basic requirement for microtia patients in addition to aesthetic needs. This quantitative framework fabrication method can reduce the learning curve, obtain satisfactory aesthetic results with few complications, and reserve a certain space for future canalplasty. Laryngoscope, 134:148-153, 2024.

SAR92 clade bacteria are potentially important DMSP degraders and sources of climate-active gases in marine environments.

Dimethylsulfoniopropionate (DMSP) is one of Earth's most abundant organosulfur molecules, which can be catabolized by marine bacteria to release climate-active gases through the cleavage and/or demethylation pathways. The marine SAR92 clade is an abundant oligotrophic group of Gammaproteobacteria in coastal seawater, but their ability to catabolize DMSP is untested. Three SAR92 clade strains isolated from coastal seawater in this study and the SAR92 representative strain HTCC2207 were all shown to catabolize DMSP as a carbon source. All the SAR92 clade strains exhibited DMSP lyase activity producing dimethylsulfide (DMS) and their genomes encoded a ratified DddD DMSP lyase. In contrast, only HTCC2207 and two isolated strains contained the DMSP demethylase dmdA gene and potentially simultaneously demethylated and cleaved DMSP to produce methanethiol (MeSH) and DMS. In SAR92 clade strains with dddD and dmdA, transcription of these genes was inducible by DMSP substrate. Bioinformatic analysis indicated that SAR92 clade bacteria containing and transcribing DddD and DmdA were widely distributed in global oceans, especially in polar regions. This study highlights the SAR92 clade of oligotrophic bacteria as potentially important catabolizers of DMSP and sources of the climate-active gases MeSH and DMS in marine environments, particularly in polar regions.IMPORTANCECatabolism of dimethylsulfoniopropionate (DMSP) by marine bacteria has important impacts on the global sulfur cycle and climate. However, whether and how members of most oligotrophic bacterial groups participate in DMSP metabolism in marine environments remains largely unknown. In this study, by characterizing culturable strains, we have revealed that bacteria of the SAR92 clade, an abundant oligotrophic group of Gammaproteobacteria in coastal seawater, can catabolize DMSP through the DMSP lyase DddD-mediated cleavage pathway and/or the DMSP demethylase DmdA-mediated demethylation pathway to produce climate-active gases dimethylsulfide and methanethiol. Additionally, we found that SAR92 clade bacteria capable of catabolizing DMSP are widely distributed in global oceans. These results indicate that SAR92 clade bacteria are potentially important DMSP degraders and sources of climate-active gases in marine environments that have been overlooked, contributing to a better understanding of the roles and mechanisms of the oligotrophic bacteria in oceanic DMSP degradation.

In situ visualization of Braun's lipoprotein on E. coli sacculi.

Braun's lipoprotein (Lpp) plays a major role in stabilizing the integrity of the cell envelope in Escherichia coli, as it provides a covalent cross-link between the outer membrane and the peptidoglycan layer. An important challenge in elucidating the physiological role of Lpp lies in attaining a detailed understanding of its distribution on the peptidoglycan layer. Here, using atomic force microscopy, we visualized Lpp directly on peptidoglycan sacculi. Lpp is homogeneously distributed over the outer surface of the sacculus at a high density. However, it is absent at the constriction site during cell division, revealing its role in the cell division process with Pal, another cell envelope-associated protein. Collectively, we have established a framework to elucidate the distribution of Lpp and other peptidoglycan-bound proteins via a direct imaging modality.

Ginsenoside Rb1 Modulates the Migration of Bone-Derived Mesenchymal Stem Cells through the SDF-1/CXCR4 Axis and PI3K/Akt Pathway.

Methods: Wound-healing assay and Transwell assay were utilized to evaluate the effect of ginsenoside Rb1 on the migration of BMSCs. RT-PCR and Western blotting were performed to evaluate the expression of stromal-derived factor 1 (SDF-1), C-X-C chemokine receptor type 4 (CXCR4), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (PKB; AKT). Results: Ginsenoside Rb1 significantly enhanced the migration of BMSCs through the activation of SDF-1, CXCR4, p-PI3K/PI3K, and p-Akt/Akt relative expression. Furthermore, this stimulus was blocked by the pretreatment with AMD3100 and LY294002. Conclusions: Ginsenoside Rb1 facilitated the migration of BMSCs through the activation of the SDF-1/CXCR4 axis and PI3K/Akt pathway.

Skin redraping for correction of lower eyelid epiblepharon combined with medial epicanthal fold: a retrospective analysis of 286 Asian children.

OBJECTIVE: This study was performed to evaluate the clinical effect of skin redraping on lower eyelid epiblepharon accompanied by a medial epicanthal fold. METHODS: This retrospective case series involved 572 eyes of 286 patients who underwent skin redraping surgery to treat lower eyelid epiblepharon accompanied by a medial epicanthal fold from January 2015 to May 2019. The postoperative surgical results were classified as "good", "fair" and "poor". The incision scars were assessed using the Vancouver scar scale. The patients' subjective satisfaction and incidence of complications were also documented. RESULTS: The mean patient age at the time of surgery was 6.9 ± 3.6 years (3-12 years), and the mean follow-up time was 32.6 ± 13.5 months (6-58 months). The clinical symptoms and severity of keratopathy were improved postoperatively. "Good" surgical outcomes were obtained in all patients, the mean Vancouver scar scale score was 1.1 ± 0.3, and hypertrophic scar formation did not occur. A total of 272 patients and their guardians were "very satisfied" with the cosmetic outcomes. CONCLUSION: Skin redraping was effective and endurable in the treatment of lower eyelid epiblepharon accompanied by a medial epicanthal fold. The postoperative scars were slight and nearly invisible, and no cases of recurrence were observed in this study.

Ginsenoside Rb1 Reduces D-GalN/LPS-induced Acute Liver Injury by Regulating TLR4/NF-κB Signaling and NLRP3 Inflammasome.

Background and Aims: The effect of ginsenoside Rb1 on D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced acute liver injury (ALI) is unknown. The aim of this study was to evaluate the effect of ginsenoside Rb1 on ALI and its underlying mechanisms. Methods: Mice were pretreated with ginsenoside Rb1 by intraperitoneal injection for 3 days before D-GalN/LPS treatment, to induce ALI. The survival rate was monitored every hour for 24 h, and serum biochemical parameters, hepatic index and histopathological analysis were evaluated to measure the degree of liver injury. ELISA was used to detect oxidative stress and inflammatory cytokines in hepatic tissue and serum. Immunohistochemistry staining, RT-PCR and western blotting were performed to evaluate the expression of toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), and NLR family, pyrin domain-containing 3 protein (NLRP3) in liver tissue and Kupffer cells (KCs). Results: Ginsenoside Rb1 improved survival with D-GalN/LPS-induced ALI by up to 80%, significantly ameliorated the increased alanine and aspartate transaminase, restored the hepatic pathological changes and reduced the levels of oxidative stress and inflammatory cytokines altered by D-GalN/LPS. Compared to the control group, the KCs were increased in the D-GalN/LPS groups but did not increase significantly with Rb1 pretreatment. D-GalN/LPS could upregulate while Rb1 pretreatment could downregulate the expression of interleukin (IL)-1ß, IL-18, NLRP3, apoptosis associated speck-like protein containing CARD (ASC) and caspase-1 in isolated KCs. Furthermore, ginsenoside Rb1 inhibited activation of the TLR4/NF-κB signaling pathway and NLRP3 inflammasome induced by D-GalN/LPS administration. Conclusions: Ginsenoside Rb1 protects mice against D-GalN/LPS-induced ALI by attenuating oxidative stress and the inflammatory response through the TLR4/NF-κB signaling pathway and NLRP3 inflammasome activation.