Roxarsone biotransformation by a nitroreductase and an acetyltransferase in Pseudomonas chlororaphis, a bacterium isolated from soil.

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid, Rox), a widely used organoarsenical feed additive, can enter soils and be further biotransformed into various arsenic species that pose human health and ecological risks. However, the pathway and molecular mechanism of Rox biotransformation by soil microbes are not well studied. Therefore, in this study, we isolated a Rox-transforming bacterium from manure-fertilized soil and identified it as Pseudomonas chlororaphis through morphological analysis and 16S rRNA gene sequencing. Pseudomonas chlororaphis was able to biotransform Rox to 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA), N-acetyl-4-hydroxy-m-arsanilic acid (N-AHPAA), arsenate [As(V)], arsenite [As(III)], and dimethylarsenate [DMAs(V)]. The complete genome of Pseudomonas chlororaphis was sequenced. PcmdaB, encoding a nitroreductase, and PcnhoA, encoding an acetyltransferase, were identified in the genome of Pseudomonas chlororaphis. Expression of PcmdaB and PcnhoA in E. coli Rosetta was shown to confer Rox(III) and 3-AHPAA(III) resistance through Rox nitroreduction and 3-AHPAA acetylation, respectively. The PcMdaB and PcNhoA enzymes were further purified and functionally characterized in vitro. The kinetic data of both PcMdaB and PcNhoA were well fit to the Michaelis-Menten equation, and nitroreduction catalyzed by PcMdaB is the rate-limiting step for Rox transformation. Our results provide new insights into the environmental risk assessment and bioremediation of Rox(V)-contaminated soils.

Inhibitory effect of polyethylene microplastics on roxarsone degradation in soils.

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid, Rox(V)), an extensively used organoarsenical feed additive, enters soils through the application of Rox(V)-containing manure and further degrades to highly toxic arsenicals. Microplastics, as emerging contaminants, are also frequently detected in soils. However, the effects of microplastics on soil Rox(V) degradation are unknown. A microcosm experiment was conducted to investigate soil Rox(V) degradation responses to polyethylene (PE) microplastics and the underlying mechanisms. PE microplastics inhibited soil Rox(V) degradation, with the main products being 3-amino-4-hydroxyphenylarsonic acid [3-AHPAA(V)], N-acetyl-4-hydroxy-m-arsanilic acid [N-AHPAA(V)], arsenate [As(V)], and arsenite [As(III)]. This inhibition was likely driven by the decline in soil pH by PE microplastic addition, which may directly enhance Rox(V) sorption in soils. The decreased soil pH further suppressed the nfnB gene related to nitroreduction of Rox(V) to 3-AHPAA(V) and nhoA gene associated with acetylation of 3-AHPAA(V) to N-AHPAA(V), accompanied by a decrease in the relative abundance of possible Rox(V)-degrading bacteria (e.g., Pseudomonadales), although the diversity, composition, network complexity, and assembly of soil bacterial communities were largely influenced by Rox(V) rather than PE microplastics. Our study emphasizes microplastic-induced inhibition of Rox(V) degradation in soils and the need to consider the role of microplastics in better risk assessment and remediation of Rox(V)-contaminated soils.

[Speciation and Pollution Assessment of Heavy Metals in Mangrove Surface Sediments in Jiulong River Estuary].

The speciation of heavy metals was analyzed using modified BCR four-step extraction methods to analyze the pollution of heavy metals in surface sediments collected from the mangrove wetland in Jiulong River Estuary. Subsequently, the pollution degree and the ecological risk of heavy metals were evaluated by using the ratio of secondary phase to primary phase (RSP), risk assessment code (RAC), and modified potential ecological risk index (MRI) assessment methods. The results of BCR four-step extraction showed that Cd (52.55%) and Mn (47.71%) mainly existed in weak-acid extractable fractions. Pb, Y, and Cu mainly existed in reducible and oxidizable fractions. Ba, Tl, V, Th, Cr, As, U, Hg, Ni, Zn, and Co mainly existed in residue fractions. The results of RSP showed that the sediments were heavily polluted by Cd and Mn and moderately polluted by Pb. Cu, Y, and Co were slightly polluted, whereas Zn, Hg, As, U, Ni, Cr, Th, V, Ba, and Tl were not polluted. The results of RAC showed that Cd and Mn were high risk, whereas Co and Zn were moderate risk. Ni, Cu, Hg, and Y were slight risk, and the other elements (U, As, Pb, Cr, V, Tl, Ba, and Th) presented no risk. The MRI results showed that the comprehensive potential ecological risk of heavy metals was serious in the surface sediments, whereas Hg and Cd were the main contribution factors. Hg was a serious potential hazard, followed by Cd. Tl was a medium potential hazard, and the other elements were low potential hazards. These results demonstrated that the mangroves were polluted by heavy metals in Jiulong River Estuary, and effective strategies should be employed to remediate the mangrove sediment in the future.

Therapeutic Response Is Associated With Antipsychotic-Induced Weight Gain in Drug-Naive First-Episode Patients With Schizophrenia: An 8-Week Prospective Study.

BACKGROUND: Some previous studies have shown that weight gain is associated with greater improvement in psychopathology during antipsychotic treatment in patients with chronic schizophrenia. However, the results are mixed due to many confounding factors. The current study aimed to investigate whether weight gain was associated with antipsychotic response in patients with antipsychotic-naive and first-episode (ANFE) DSM-IV--diagnosed schizophrenia. METHODS: 526 ANFE patients and 313 healthy controls were enrolled in this study, which was conducted from January 2012 to December 2018. Treatment outcome was measured by the Positive and Negative Syndrome Scale (PANSS) at baseline and follow-up. Weight was measured at baseline and at the end of 8 weeks. RESULTS: After treatment, PANSS scores were significantly reduced as follows: positive symptoms (-10.40; 95% CI, -9.31 to -10.60), negative symptoms (-5.01; 95% CI, -4.43 to -5.54), general psychopathology (-13.01; 95% CI, -12.01 to -14.01), and PANSS total score (-28.53; 95% CI, -26.73 to -30.33). In addition, the average weight of ANFE patients increased by 2.89 kg (95% CI, 2.55 to 3.22), although it was still lower than the average weight of healthy controls. The proportion of patients with weight gain ≥ 7% after treatment was 38.2%. Weight gain was positively associated with decrease of PANSS positive symptoms, general psychopathology, and total score (all P < .05). Multiple linear regression analysis showed that baseline weight, decrease of PANSS total score, and sex were significantly associated with weight gain after treatment. CONCLUSIONS: Our findings suggest that there is a significant association between weight gain and improvement of clinical symptoms after 8 weeks of antipsychotic treatment in patients with ANFE schizophrenia. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04076371.

Kiwifruit Genome Database (KGD): a comprehensive resource for kiwifruit genomics.

Kiwifruit (Actinidia spp.) plants produce economically important fruits containing abundant, balanced phytonutrients with extraordinarily high vitamin C contents. Since the release of the first kiwifruit reference genome sequence in 2013, large volumes of genome and transcriptome data have been rapidly accumulated for a handful of kiwifruit species. To efficiently store, analyze, integrate, and disseminate these large-scale datasets to the research community, we constructed the Kiwifruit Genome Database (KGD; http://kiwifruitgenome.org/). The database currently contains all publicly available genome and gene sequences, gene annotations, biochemical pathways, transcriptome profiles derived from public RNA-Seq datasets, and comparative genomic analysis results such as syntenic blocks and homologous gene pairs between different kiwifruit genome assemblies. A set of user-friendly query interfaces, analysis tools and visualization modules have been implemented in KGD to facilitate translational and applied research in kiwifruit, which include JBrowse, a popular genome browser, and the NCBI BLAST sequence search tool. Other notable tools developed within KGD include a genome synteny viewer and tools for differential gene expression analysis as well as gene ontology (GO) term and pathway enrichment analysis.

[Research advances on hypolipidemic effect of polysaccharides].

Hyperlipidemia is a systemic chronic metabolic disease caused by dyslipidemia in the body. It is an important risk factor of accelerating atherosclerosis, which will cause coronary heart disease, thrombus and other cardiovascular diseases, so it is a "invisible killer" for human health. Controlling and lowering blood lipids can reduce the risk of cardiovascular and cerebrovascular diseases. The current therapies for hyperlipidemia mainly include chemical synthetic medicines. However, long-term use of hypolipidemic drugs would cause various side effects, and the demand of effective and nontoxic drugs for hyperlipidemia patients is eager. Polysaccharide has attracted worldwide concerns due to its characteristics of good biocompatibility and less side effects. Polysaccharide is a kind of biological macromolecule which is widely found in plant cell walls, animal cell membranes and microorganism cell walls. A number of studies have shown that polysaccharides from natural materials have broad biological activities, such as anti-tumor, immunomodulatory, antioxidant, hypoglycemic, and hypolipidemic effects, with broad application prospect. This paper has reviewed and summarized the polysaccharides with hypolipidemic effect and their mechanisms which have been reported at home and abroad, hoping to provide certain reference for their development and application in lowering blood lipids.

Enhanced butanol production by solvent tolerance Clostridium acetobutylicum SE25 from cassava flour in a fibrous bed bioreactor.

To enhance the butanol productivity and reduce the material cost, acetone, butanol, and ethanol fermentation by Clostridium acetobutylicum SE25 was investigated using batch, repeated-batch and continuous cultures in a fibrous bed bioreactor, where cassava flour was used as the substrate. With periodical nutrient supplementation, stable butanol production was maintained for about 360h in a 6-cycle repeated-batch fermentation with an average butanol productivity of 0.28g/L/h and butanol yield of 0.32g/g-starch. In addition, the highest butanol productivity of 0.63g/L/h and butanol yield of 0.36g/g-starch were achieved when the dilution rate were investigated in continuous production of acetone, butanol, and ethanol using a fibrous bed bioreactor, which were 231.6% and 28.6% higher than those of the free-cell fermentation. On the other hand, this study also successfully comfirmed that the biofilm can provide an effective protection for the microbial cells which are growing in stressful environment.

Luciferase assay to screen tumour-specific promoters in lung cancer.

OBJECTIVE: Specific promoters could improve efficiency and ensure the safety of gene therapy. The aim of our study was to screen examples for lung cancer. METHODS: The firefly luciferase gene was used as a reporter, and promoters based on serum markers of lung cancer were cloned. The activity and specificity of seven promoters, comprising CEACAM5 (carcinoembryonic antigen, CEA), GRP (Gastrin-Releasing Peptide), KRT19 (cytokeratin 19, KRT), SFTPB (surfactant protein B, SP-B), SERPINB3 (Squamous Cell Carcinoma Antigen, SCCA), SELP (Selectin P, Granule Membrane Protein 140 kDa, Antigen CD62, GMP) and DKK1 (Dickkopf-1) promoters were compared in lung cancer cells to obtain cancer-specific examples with strong activity. RESULTS: The CEACAM5, DKK1, GRP, SELP, KRT19, SERPINB3 and SFTPB promoters were cloned. Furthermore, we successfully constructed recombinant vector pGL-CEACAM5 (DKK1, GRP, SELP, KRT19, SERPINB3 and SFTPB) contained the target gene. After cells were transfected with recombinant plasmids, we found that the order of promoter activity from high to low was SERPINB3, DKK1, SFTPB, KRT19, CEACAM5, SELP and GRP and the order for promoters regarding specificity and high potential were SERPINB3, DKK1, SELP, SFTPB, CEACAM5, KRT19 and GRP. CONCLUSION: The approach adopted is feasible to screen for new tumour specific promoters with biomarkers. In addition, the screened lung-specific promoters might have potential for use in lung cancer targeted gene therapy research.