Seasonal Patterns of Picocyanobacterial Community Structure in the Kuroshio Current.

The nutrient-scarce, warm, and high-salinity Kuroshio current has a profound impact on both the marine ecology of the northwestern Pacific Ocean and the global climate. This study aims to reveal the seasonal dynamics of picoplankton in the subtropical Kuroshio current. Our results showed that one of the picocyanobacteria, Synechococcus, mainly distributed in the surface water layer regardless of seasonal changes, and the cell abundance ranged from 104 to 105 cells mL-1. In contrast, the maximum concentration of the other picocyanobacteria, Prochlorococcus, was maintained at more than 105 cells mL-1 throughout the year. In the summer and the autumn, Prochlorococcus were mainly concentrated at the water layer near the bottom of the euphotic zone. They were evenly distributed in the euphotic zone in the spring and winter. The stirring effect caused by the monsoon determined their distribution in the water column. In addition, the results of 16S rRNA gene diversity analysis showed that the seasonal changes in the relative abundance of Synechococcus and Prochlorococcus in the surface water of each station accounted for 20 to 40% of the total reads. The clade II of Synechococcus and the High-light II of Prochlorococcus were the dominant strains in the waters all year round. Regarding other picoplankton, Proteobacteria and Actinobacteria occupied 45% and 10% of the total picoplankton in the four seasons. These data should be helpful for elucidating the impacts of global climate changes on marine ecology and biogeochemical cycles in the Western Boundary Currents in the future.

Single-cell RNA sequencing uncovers the individual alteration of intestinal mucosal immunocytes in Dusp6 knockout mice.

Single-cell RNA sequencing (scRNA-seq) approach can broadly and specifically evaluate the individual cells with minimum detection bias. To explore the individual compositional and transcriptional alteration of intestinal leukocytes in the Dual Specificity Phosphatase six knockout (D6KO) mice, we performed a scRNA-seq followed by the cell type annotation based on ImmGen database. Composition assessments found that D6KO-derived intestinal leukocytes tend to stay inactivate or immature status. The enrichment analysis showed that D6KO-derived intestinal leukocytes are less sensitive to microbes. The mod PhEA phenotypic analysis showed that the D6KO leukocytes may link to not only immune-associated but also diverse previously non-immune-related diseases. Integrating our dataset with the published dataset GSE124880 generated a comprehensive dataset for exploring intestinal immunity. Down-regulation of Ccl17 gene was found in the D6KO-derived dendritic cells. Our results demonstrated the advantage of applying scRNA-seq for dissecting the individual alteration of intestinal leukocytes, particularly in the D6KO mice at a naive state.

Identification of a gut microbiota member that ameliorates DSS-induced colitis in intestinal barrier enhanced Dusp6-deficient mice.

Strengthening the gut epithelial barrier is a potential strategy for management of gut microbiota-associated illnesses. Here, we demonstrate that dual-specificity phosphatase 6 (Dusp6) knockout enhances baseline colon barrier integrity and ameliorates dextran sulfate sodium (DSS)-induced colonic injury. DUSP6 mutation in Caco-2 cells enhances the epithelial feature and increases mitochondrial oxygen consumption, accompanied by altered glucose metabolism and decreased glycolysis. We find that Dusp6-knockout mice are more resistant to DSS-induced dysbiosis, and the cohousing and fecal microbiota transplantation experiments show that the gut/fecal microbiota derived from Dusp6-knockout mice also confers protection against colitis. Further culturomics and mono-colonialization experiments show that one gut microbiota member in the genus Duncaniella confers host protection from DSS-induced injury. We identify Dusp6 deficiency as beneficial for shaping the gut microbiota eubiosis necessary to protect against gut barrier-related diseases.

Copper(I) nitro complex with an anionic [HB(3,5-Me2Pz)3]− ligand: a synthetic model for the copper nitrite reductase active site.

The new copper(I) nitro complex [(Ph(3)P)(2)N][Cu(HB(3,5-Me(2)Pz)(3))(NO(2))] (2), containing the anionic hydrotris(3,5-dimethylpyrazolyl)borate ligand, was synthesized, and its structural features were probed using X-ray crystallography. Complex 2 was found to cocrystallize with a water molecule, and X-ray crystallographic analysis showed that the resulting molecule had the structure [(Ph(3)P)(2)N][Cu(HB(3,5-Me(2)Pz)(3))(NO(2))]·H(2)O (3), containing a water hydrogen bonded to an oxygen of the nitrite moiety. This complex represents the first example in the solid state of an analogue of the nitrous acid intermediate (CuNO(2)H). A comparison of the nitrite reduction reactivity of the electron-rich ligand containing the CuNO(2) complex 2 with that of the known neutral ligand containing the CuNO(2) complex [Cu(HC(3,5-Me(2)Pz)(3))(NO(2))] (1) shows that reactivity is significantly influenced by the electron density around the copper and nitrite centers. The detailed mechanisms of nitrite reduction reactions of 1 and 2 with acetic acid were explored by using density functional theory calculations. Overall, the results of this effort show that synthetic models, based on neutral HC(3,5-Me(2)Pz)(3) and anionic [HB(3,5-Me(2)Pz)(3)](-) ligands, mimic the electronic influence of (His)(3) ligands in the environment of the type II copper center of copper nitrite reductases (Cu-NIRs).

Characterization of a new copper(I)-nitrito complex that evolves nitric oxide.

The complexes [Cu(kappa(2)-Ph(2)PC(6)H(4)(o-OMe))(2)(CH(3)CN)](BF(4)) (1) and [CuCl(Ph(2)PC(6)H(4)(o-OMe))(2)] (2) have been prepared by treating [Cu(CH(3)CN)(4)](BF(4)) or CuCl with two equivalents o-(diphenylphosphino)anisole (Ph(2)PC(6)H(4)(o-OMe)) at room temperature, respectively. The reaction of 1 and (PPN)(NO(2)) in acetonitrile solution affords a neutral compound [Cu(Ph(2)PC(6)H(4)(o-OMe))(2)(ONO)] (3). In contrast to the synthesis of 3, mixing NaNO(2) and 1 in MeOH yielded a unique dicopper(I) cationic species, [((Ph(2)PC(6)H(4)(o-OMe))(2)Cu)(2)(mu-NO(2))](+) (4) after ether/CH(2)Cl(2) crystallization. The molecular structures of 1-4 have been determined by an X-ray diffraction study. The copper(I)-nitrito adduct 3 containing phosphine-ether ligands forms nitric oxide gas from the reaction with acetic acid, suggesting the first example and model compound in the asymmetric O-bound copper(I) nitrite intermediate microenvironment of copper nitrite reductases (Cu-NIRs).