Response of bacterial community structure to different ecological niches and their functions in Korean pine forests.

A healthy plant microbiome is diverse, taxonomically-structured, and gives its plant host moderate advantages in growth, development, stress tolerance, and disease resistance. The plant microbiome varies with ecological niches and is influenced by variables that are complex and difficult to separate from each other, such as the plant species, soil, and environmental factors. To explore the composition, diversity, and functions of the bacterial community of Korean pine forests, we used high-throughput sequencing to study five areas with different forest ages from June to October 2017 in northeast China. We obtained 3,247 operational taxonomic units (OTUs) based on 16S rRNA gene sequencing via an Illumina Hi-seq platform. A total of 36 phyla and 159 known genera were classified. The Shannon index of the bacterial community from the rhizospheric soil was significantly higher (p < 0.01, n = 10) than that of the root tips. Beta-diversity analysis confirmed that the bacterial community of the rhizospheric soil was significantly different (p < 0.001) from the root tips. Nine bacterial phyla were dominant (relative richness > 1%) in the rhizospheric soil, but there were six dominant phyla in the root tips. Proteobacteria was the core flora in the root tips with a relative abundance of more than 50%. It is known that the formation of bacterial communities in the rhizospheric soil or the root is mainly caused by the processes of selection, and we found a relatively high abundance of a few dominant species. We further analyzed the correlations between the bacterial community from the rhizospheric soil with that of the root tips, as well as the correlations of the bacterial community with soil physicochemical properties and climate factors. We used Functional Annotation of the Prokaryotic Tax (FAPROTAX) to predict the functions of the bacterial community in the rhizospheric soil and root tips. Five related phototrophic functions, nine nitrogen cycle functions, two related chemoheterotrophic functions, and two others were predicted. The abundance of the bacteria phyla performing relevant functions was different in the rhizospheric soil than in the root tips. These functions were significantly influenced by the contents of nitrogen, phosphorus, and potassium in the soil habitat. The bacterial composition and functions in the rhizospheric soil and root tips of Korean pine were analyzed, and the results demonstrated the importance of soil and plant species on the bacterial community in the below ground plant microbiome.

Angiotensin-converting enzyme inhibitors prevent liver-related events in nonalcoholic fatty liver disease.

BACKGROUND AND AIMS: Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) can inhibit liver fibrogenesis in animal models. We aimed to evaluate the impact of ACEI/ARB use on the risk of liver cancer and cirrhosis complications in patients with NAFLD. APPROACH AND RESULTS: We conducted a retrospective, territory-wide cohort study of adult patients with NAFLD diagnosed between January 2000 and December 2014 to allow for at least 5 years of follow-up. ACEI or ARB users were defined as patients who had received ACEI or ARB treatment for at least 6 months. The primary endpoint was liver-related events (LREs), defined as a composite endpoint of liver cancer and cirrhosis complications. We analyzed data from 12,327 NAFLD patients (mean age, 54.2 ± 14.7 years; 6163 men [50.0%]); 6805 received ACEIs, and 2877 received ARBs. After propensity score weighting, ACEI treatment was associated with a lower risk of LREs (weighted subdistribution hazard ratio [SHR], 0.48; 95% CI, 0.35-0.66; p < 0.001), liver cancer (weighted SHR, 0.46; 95% CI, 0.28-0.75; p = 0.002), and cirrhosis complications (weighted SHR, 0.42; 95% CI, 0.27-0.66; p < 0.001), but ARB was not. In subgroup analysis, ACEI treatment was associated with greater reduction in LREs in patients with chronic kidney diseases (CKDs) than those without (CKD-weighted SHR, 0.74; 95% CI, 0.52-0.96; p = 0.036; non-CKD-weighted SHR, 0.15; 95% CI, 0.07-0.33; p < 0.001). CONCLUSIONS: ACEI, rather than ARB, treatment is associated with a lower risk of LREs in NAFLD patients, especially among those with CKD.

Association of metformin use on metabolic acidosis in diabetic patients with chronic hepatitis B-related cirrhosis and renal impairment.

BACKGROUND AND AIMS: Metformin is an oral anti-hyperglycemic recommended by the American Diabetes Association (ADA) as a preferred initial pharmacologic agent for type 2 diabetes. Metabolic acidosis is a rare yet severe side effect of it. We examined the association of metformin use and dosage on the risk of metabolic acidosis in diabetic patients with different degrees of chronic hepatitis B (CHB)-related cirrhosis and chronic kidney disease (CKD). METHODS: Metabolic acidosis was defined by blood pH ≤7.35, together with lactate >5 mmol/L or arterial bicarbonate ≤18 mmol/L or venous bicarbonate ≤21 mmol/L, and/or diagnosis codes. Child-Pugh class and CKD stage were included in the model as time-dependent covariates. Age, gender, comorbidities, and use of relevant medications were adjusted as covariates. Maximum daily dose of metformin was classified into ≤1000 mg and >1000 mg. RESULTS: We identified 4431 diabetic patients with CHB-related cirrhosis between 2000 and 2017 from a territory-wide database in Hong Kong. The risk of metabolic acidosis increased with Child-Pugh class B and C cirrhosis regardless of CKD stage (adjusted subdistribution hazard ratio [aSHR] ranged from 3.50 to 86.16). Metformin use was associated with a higher risk in patients with Child-Pugh class B or C cirrhosis and stage 3A CKD or above (aSHR ranged from 1.55 to 2.46). In stage 4/5 CKD, a daily dose of metformin ≤1000 mg was still associated with a higher risk of metabolic acidosis regardless of the severity of cirrhosis (aSHR ranged from 2.45 to 3.92). CONCLUSION: In conclusion, patients with Child-Pugh class B cirrhosis or above were at a higher risk of metabolic acidosis. Metformin further increased the risk in patients with Child-Pugh class B cirrhosis or above and stage 3A CKD or above. Dose adjustment in stage 4/5 CKD did not reduce the risk of metabolic acidosis.

Colonoscopy and Risk of Colorectal Cancer in Patients With Nonalcoholic Fatty Liver Disease: A Retrospective Territory-Wide Cohort Study.

The benefit of colonoscopy and/or polypectomy for colorectal cancer (CRC) prevention in patients with nonalcoholic fatty liver disease (NAFLD) remains unclear. We aimed to estimate the incidence rate of CRC in patients with NAFLD who had and had not undergone colonoscopy. We conducted a retrospective territory-wide cohort study for patients aged over 40 years with NAFLD identified with the International Classification of Diseases, Ninth Revision, Clinical Modification codes between January 1, 2000, and December 31, 2014. Patients were followed until CRC diagnosis, death, or December 31, 2017. We estimated CRC incidence and standardized incidence ratio (SIR) using the general population of Hong Kong as reference. We included 8,351 patients with NAFLD in the final analysis (median age, 56.2 years; interquartile ratio [IQR], 49.2-65.3 years; 45.4% male; median follow-up, 7.4 years; IQR, 5.4-9.6 years). Compared with the general population, patients with NAFLD who had not undergone colonoscopy had a higher incidence of CRC (SIR, 2.20; 95% confidence interval [CI], 1.64-2.88; P < 0.001). Patients with NAFLD who had undergone colonoscopy had a lower incidence of CRC (SIR, 0.54; 95% CI, 0.37-0.75; P < 0.001), especially among those aged above 50 years or with diabetes mellitus (DM). Patients with NAFLD with a high fibrosis-4 (FIB-4) score (>2.67) had a significantly higher risk of CRC after adjusting for demographic and metabolic factors. Conclusion: Patients with NAFLD who had undergone colonoscopy had a lower incidence of CRC than the general population, especially among those aged ≥50 years or with DM. A high FIB-4 index was associated with a higher risk of CRC.

Similarly low risk of hepatocellular carcinoma after either spontaneous or nucleos(t)ide analogue-induced hepatitis B surface antigen loss.

BACKGROUND: It is unknown whether patients with chronic hepatitis B (CHB) who achieved hepatitis B surface antigen (HBsAg) seroclearance spontaneously or following anti-viral therapy have similar clinical outcomes. AIM: To compare the risk of hepatocellular carcinoma (HCC) in patients with CHB who either cleared HBsAg spontaneously or following anti-viral therapy METHODS: Adult CHB-monoinfected patients who cleared HBsAg between January 2000 and March 2019 were identified from a territory-wide database in Hong Kong. Patients with liver transplantation and/or HCC before HBsAg loss were excluded. Patients' demographics, comorbidities, anti-viral treatment, laboratory parameters and HCC development were analysed. RESULTS: Of 7,124 identified patients with CHB who cleared HBsAg, mean age was 58.1 ± 13.8 years; 4,340 (60.9%) were male; 451 (6.3%) had cirrhosis; 5,917 (83.1%) and 1,207 (16.9%) had spontaneous and nucleos(t)ide analogue (NA)-induced HBsAg seroclearance, respectively. Most patients had normal liver function at HBsAg loss. Patients with NA-induced HBsAg seroclearance were younger, and more likely to be male and cirrhotic than patients with spontaneous HBsAg loss. At a median (interquartile range) follow-up of 4.3 (2.2-7.6) years, 97 (1.6%) and 16 (1.3%) patients with spontaneous and NA-induced HBsAg loss developed HCC, respectively. Patients who achieved NA-induced HBsAg loss had comparable HCC risk as those with spontaneous HBsAg loss (adjusted subdistribution hazard ratio 0.75, 95% CI 0.43-1.32, P = 0.323). The results remained robust in propensity score weighting and matching analyses. CONCLUSION: The HCC risk was similarly low after either spontaneous or NA-induced HBsAg seroclearance in a territory-wide cohort of patients with CHB who had cleared HBsAg.

Phosphoproteomics reveals the apoptotic regulation of aspirin in the placenta of preeclampsia-like mice.

Preeclampsia (PE) is a severe gestational complication, and dysfunctional placenta plays an essential role in PE pathogenesis. Although low-dose aspirin is currently the most promising prophylactic drug for PE prevention, the exact mechanism of aspirin remains unclear. A previous study reported that treatment with low-dose aspirin could ameliorate PE-like symptoms in lipopolysaccharide (LPS)-induced PE-like mouse model. This study aimed to uncover the potential mechanism of aspirin action in PE through quantitative phosphoproteomics comparison. We established the following four groups: a control (CTRL) group, an LPS-treated (L) group, an LPS + aspirin co-treatment (LA) group, and an aspirin-treated (A) group. A total of 4350 phosphosites and 4170 phosphopeptides from 1866 phosphoproteins were identified in the placenta on embryonic day 13.5. Among the significantly altered phosphoproteins identified, apoptosis-related pathways were significantly regulated in both the L group vs. CTRL group and the LA group vs. L group comparisons. We demonstrated that apoptosis was increased in the placenta of PE-like mice and was inhibited in the LA group by quantify the apoptosis-positive cells and the protein levels of cleaved caspase 3, 8, and 9. Moreover, the phosphorylation of HSP90ß (S254) and GSK3ß (Y216) may be a crucial factor in the aspirin-mediated regulation of apoptosis according to protein-protein interaction analysis. This study revealed that apoptosis regulation is a mechanism of aspirin action in PE, particularly in women with over-activated inflammation. The phosphorylation of HSP90ß (S254) and GSK3ß (Y216) could be the key intervention targets.

Diverse Coordinative Zinc Complexes Containing Amido-Pyridinate Ligands: Structural and Catalytic Studies.

In this work, zinc complexes containing amidopyridinate ligands substituted with different pendant arms have been described. Treatment of ligand precursors with ZnEt2 at a 1:1 ratio in THF yields zinc ethyl complexes (PyN C 1 Py )2(ZnEt)2 (1) and (PyN C 2 NMe 2 )2(ZnEt)2 (2), respectively. Complexes 1 and 2 show the same geometry as a distorted tetrahedron, but adopt different coordination behaviors supported by the ligands. Complex 1 represents a rare and a non-centrosymmetric mode, which the amido group bridges two zinc centers to form a six-membered ring. However, complex 2 shows a centrosymmetric mode, which the pyridine group links to the zinc centers to form an eight-membered ring. Recrystallization of complex 2 gives an additional complex (PyN C 2 NMe 2 )4Zn3(µ3-O) (3). We attempted to prepare zinc benzyl oxide complexes but afforded only a self-assembly cubane complex Zn7Et6(OBn)8 (4). All molecular structures 1-4 are characterized depending on both single-crystal X-ray and spectroscopic data. Furthermore, their catalytic properties toward the ring opening polymerization of ε-caprolactone and L-lactide, using benzyl alcohol as the initiation reagent, are under investigation.

[Toxin-neutralizing monoclonal antibodies to the different domains of anthrax protective antigen].

Anthrax toxin from Bacillus anthracis is a three-component toxin consisting of lethal factor (LF), edema factor (EF), and protective antigen (PA). PA binds to target cells and transports LF or EF into the cell cytosol where they carry out their enzymatic functions. PA can induce protective immunity to the infection of the bacterium and is the major component in the only anthrax vaccine approved by FDA of USA. Mouse hybridoma clones specifically secreting anti-PA monoclonal antibodies (MAbs) were generated by cell fusion technique and their ability to neutralize anthrax lethal toxin activities was screened in vitro on a toxin-sensitive cell line. Nine toxin-neutralizing MAbs obtained were then characterized for the domains of PA they recognize, and the epitope regions they bind were analyzed by competitive binding ELISA. It was found that these MAbs bind four potential neutralizing epitope regions in three different domains of PA. Four MAbs bind to two non-overlapping epitope regions in domain 4 of PA and may prevent the binding of PA to its cell receptor. Four MAbs bind to domain 2, a domain involved in membrane insertion. One MAb binds to domain 3, a region involved in the oligomerization of PA. The results provided supporting evidence that PA has several neutralizing epitopes, and offered potential immunotherapeutic agents for the treatment of anthrax.

[Expression, purification and characterization of the recombinant anthrax protective antigen].

An expression plasmid carrying anthrax protective antigen (PA) gene was constructed, which has an OmpA signal sequence attached to the 5' end of PA gene. The plasmid was transformed into E. coli and induced to express recombinant PA (rPA) . The recombinant protein, about 10% of the total bacterial protein in volume, was secreted to the periplasmic space of the cell. After a purification procedure including ion-exchange, hydrophobic interaction chromatography, and gel filtration, about 15 mg of 95 % pure rPA was obtained from 1-liter culture. The bioactivity of rPA was proved by in vitro cytotoxicity assay. The polyclonal antiserum from rabbits immunized with rPA could inhibit the action of anthrax lethal toxin in vitro, which suggests that antibodies against rPA can provide high passive protection against anthrax. The results reported here may be helpful to develop a safe and efficacious recombinant PA vaccine against anthrax.