AdpA, a developmental regulator, promotes ε-poly-L-lysine biosynthesis in Streptomyces albulus.

BACKGROUND: AdpA is a global regulator of morphological differentiation and secondary metabolism in Streptomyces, but the regulatory roles of the Streptomyces AdpA family on the biosynthesis of the natural product ε-poly-L-lysine (ε-PL) remain unidentified, and few studies have focused on increasing the production of ε-PL by manipulating transcription factors in Streptomyces. RESULTS: In this study, we revealed the regulatory roles of different AdpA homologs in ε-PL biosynthesis and morphological differentiation and effectively promoted ε-PL production and sporulation in Streptomyces albulus NK660 by heterologously expressing adpA from S. neyagawaensis NRRLB-3092 (adpASn). First, we identified a novel AdpA homolog named AdpASa in S. albulus NK660 and characterized its function as an activator of ε-PL biosynthesis and morphological differentiation. Subsequently, four heterologous AdpA homologs were selected to investigate their phylogenetic relationships and regulatory roles in S. albulus, and AdpASn was demonstrated to have the strongest ability to promote both ε-PL production and sporulation among these five AdpA proteins. The ε-PL yield of S. albulus heterologously expressing adpASn was approximately 3.6-fold higher than that of the control strain. Finally, we clarified the mechanism of AdpASn in enhancing ε-PL biosynthesis and its effect on ε-PL polymerization degree using real-time quantitative PCR, microscale thermophoresis and MALDI-TOF-MS. AdpASn was purified, and its seven direct targets, zwf, tal, pyk2, pta, ack, pepc and a transketolase gene (DC74_2409), were identified, suggesting that AdpASn may cause the redistribution of metabolic flux in central metabolism pathways, which subsequently provides more carbon skeletons and ATP for ε-PL biosynthesis in S. albulus. CONCLUSIONS: Here, we characterized the positive regulatory roles of Streptomyces AdpA homologs in ε-PL biosynthesis and their effects on morphological differentiation and reported for the first time that AdpASn promotes ε-PL biosynthesis by affecting the transcription of its target genes in central metabolism pathways. These findings supply valuable insights into the regulatory roles of the Streptomyces AdpA family on ε-PL biosynthesis and morphological differentiation and suggest that AdpASn may be an effective global regulator for enhanced production of ε-PL and other valuable secondary metabolites in Streptomyces.

Genetic transmission networks of HIV-1 CRF07_BC strain among HIV-1 infections with virologic failure of ART in a minority area of China: a population-based study.

BACKGROUND: The drug resistance and the virologic failure of antiretroviral therapy (ART) are quite severe in Liangshan. A better understanding of the virologic failure of ART and the HIV-1 transmission network dynamics is essential for the surveillance and prevention of HIV. Here, we analyzed the HIV-1 CRF07_BC strain genetic transmission networks and their associated factors among people living with HIV-1 (PLWH) who had virologic failure of ART by using close genetic links. METHODS: The drug-resistant mutations were determined using the Stanford University HIV Drug Resistance Database. HIV-1 pol genes sequences were used for phylogenetic and genotypic drug resistance analysis. The genetic transmission networks were performed by comparing sequences, constructing the phylogenetic tree, calculating the pairwise distance, and visualizing the network. RESULTS: A total of 1050 PLWH with CRF07_BC pol sequences were finally identified and included in the genetic transmission network analysis from 2016 to 2017. Of the 1050 CRF07_BC pol sequences, 346 (32.95%) fell into clusters at a genetic distance of 0.006, resulting in 137 clusters ranging in size from 2 to 40 individuals. Subjects who were widowed or divorced were less likely to form a genetic transmission network (adjusted OR: 0.50), while subjects who had shared a needle ≥ five times were more likely to form a network (adjusted OR: 1.88). CONCLUSIONS: The genetic transmission networks revealed the complex transmission pattern, highlighting the urgent need for transmission monitoring of virologic failure of ART and selection of more effective therapeutic regimens to promote viral suppression.

Prevalence and determinants of virological failure, genetic diversity and drug resistance among people living with HIV in a minority area in China: a population-based study.

BACKGROUND: Liangshan Yi Autonomous Prefecture is one of the areas that most severely affected by human immunodeficiency virus (HIV) in China, and virological failure on antiretroviral therapy (ART) is serious in this area. Analyses of prevalence and determinants of ART failure, the genetic diversity and drug resistance among people living with HIV (PLWH) helps improve HIV treatment efficiency and prevent HIV transmission. METHODS: A total of 5157 PLWH were recruited from 2016 to 2017. The venous blood samples were subjected to RT-PCR, followed by sequencing of the HIV-1 pol gene, targeting the protease and reverse transcriptase fragments. HIV-1 diversity was analyzed using the DNAStar software and drug resistance mutations were analyzed using the Stanford University HIV Drug Resistance Database. RESULTS: A total of 2156 (41.81%) PLWH showed virological failure on ART. Males (ORm = 1.25), heterosexual behaviors and drug injection (ORm = 1.44) and mother to child transmission routes (ORm = 1.58), the clinical stage of AIDS (ORm = 1.35), having used illicit drugs and shared the needles (1-4 times: ORm = 1.34; more than 5 times: ORm = 1.52), having ever replaced ART regimen (ORm = 1.48) increased the risk of virological failure among PLWH, while higher education lever (ORm = 0.77) and ≥ 12 months on ART (12 ~ 36 months: ORm = 0.72; ≥36 months: ORm = 0.66) was associated with lower likelihood of virological failure. The data revealed that CRF07_BC (1508, 95.62%) were the most common strains, and the drug-resistant rate was 32.10% among PLWH with virological failure in this area. The high frequencies of drug resistance were found in EFV and NVP of NNRTIs, ABC, FTC and 3TC of NRTIs, and TPV/r in PIs. The most common mutations in NNRTIs, NRTIs and PIs were K103N/KN (64.69%), M184V/MV/I (36.29%) and Q58E/QE (4.93%), respectively. CONCLUSION: We concluded that surveillance of virological failure, HIV-1 subtypes, and drug resistance to understand HIV-1 epidemiology and guide modification of ART guidelines, and target prevention and control strategies should be formatted to reduce the virological failure and drug resistance to promote viral suppression and prevent HIV-1 transmission.

A novel "AIE + ESIPT" near-infrared nanoprobe for the imaging of γ-glutamyl transpeptidase in living cells and the application in precision medicine.

γ-Glutamyl transpeptidase (GGT) has been reported as a biomarker of hepatocellular carcinoma (HCC), and its imaging is of great benefit for early detection in precise medicine as well as intraoperative navigation. Herein, we have designed and synthesized a novel near-infrared fluorescent probe coupled aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) effect for the detection of GGT. Thanks to conjugated glutamate acid, this probe could be dispersed in aqueous solution and showed barely any fluorescence emission. Through a GGT-mediated enzymatic reaction, the aggregation state of the probe in aqueous solution was changed and an intramolecular hydrogen bond was formed, resulting in an enhanced fluorescence emission. An excellent linear relationship was observed and the concentration of GGT measured was in the range of 10-90 U L-1 with a limit of detection calculated at 2.9 U L-1. Its feasibility has been confirmed by detecting GGT in HepG2 cells with high specificity and long-term sustainability, satisfying clinical need. Moreover, this nanoprobe showed great potential for precise medicine guided surgery by realizing fluorescence imaging in human liver tumour tissue and distinguishing it from normal tissue. Thus, we supposed that our AIE coupled ESIPT fluorescent nanoprobe has great potential in the early detection of HCC, the selective fluorescence imaging of GGT positive cells during surgery and application in precision medicine.

Regulation of the muscle fiber microenvironment by activated satellite cells during hypertrophy.

Our aim in the current study was to determine the necessity of satellite cells for long-term muscle growth and maintenance. We utilized a transgenic Pax7-DTA mouse model, allowing for the conditional depletion of > 90% of satellite cells with tamoxifen treatment. Synergist ablation surgery, where removal of synergist muscles places functional overload on the plantaris, was used to stimulate robust hypertrophy. Following 8 wk of overload, satellite cell-depleted muscle demonstrated an accumulation of extracellular matrix (ECM) and fibroblast expansion that resulted in reduced specific force of the plantaris. Although the early growth response was normal, an attenuation of hypertrophy measured by both muscle wet weight and fiber cross-sectional area occurred in satellite cell-depleted muscle. Isolated primary myogenic progenitor cells (MPCs) negatively regulated fibroblast ECM mRNA expression in vitro, suggesting a novel role for activated satellite cells/MPCs in muscle adaptation. These results provide evidence that satellite cells regulate the muscle environment during growth.

[Drug-resistance characteristics of CRF01_AE and CRF07_BC subtypes of HIV-1 strains in Sichuan province].

OBJECTIVE: To investigate the drug resistance of HIV patients to the HIV-1 CRF01_AE and CRF07_BC strains in Sichuan province during 2010 to 2013. METHODS: 1.5 ml of plasma were collected from AIDS patients who had been receiving anti-retroviral treatment for over 6 months but still had a HIV-1 virus load of over 1 000 copies/ml from January 1, 2010 to December 31, 2013 in Sichuan province. Genetic analysis of the HIV-1 pol gene was performed using self-established method, and patients with a positive drug-resistant HIV-1 pol gene mutation were included. HIV-1 poly gene was successfully sequenced for a total of 1 213 patients. Drug resistance of different HIV-1 strains was compared with χ2 test or Fisher exact test. RESULTS: 558 cases (46.0%) of the 1 213 successfully sequenced patients were infected by HIV-1-strains with drug-resistant mutations, including 327 cases (58.6%) infected by CRF01_AE strain, 126 (22.6%) by CRF07_BC strain, 46 (8.2%) by CRF08_BC strain, 33 (5.9%) by B strain, 4 (0.7%) by C strain, 1 (0.2%) by CRF02_AG strain, and 21 (3.8%) by unidentified strains. Drug-resistant mutation analysis revealed that L33, F116, L74, Q151, and T69 resistance mutations occurred only in the CRF01_AE strain, while A71, K43, and Q58 resistance mutations occurred only in the CRF07_BC strain; in nuclear nucleoside reverse transcriptase inhibitors (NRTIs) and non nucleoside reverse transcriptase inhibitors (NNRTIs), CRF01_AE subtype strains showed highly resistant rate were higher than CRF07_BC, CRF08_BC and B subtype strains, with the differences were statistically significant (P<0.05). CONCLUSION: The drug-resistant HIV-1 strains in Sichuan mainly included the CRF01_AE and CRF07_BC strains, which had different resistance mutations.

The geostatistic-based spatial distribution variations of soil salts under long-term wastewater irrigation.

The purpose of this study was to determine and evaluate the spatial changes in soil salinity by using geostatistical methods. The study focused on the suburb area of Beijing, where urban development led to water shortage and accelerated wastewater reuse to farm irrigation for more than 30 years. The data were then processed by GIS using three different interpolation techniques of ordinary kriging (OK), disjunctive kriging (DK), and universal kriging (UK). The normality test and overall trend analysis were applied for each interpolation technique to select the best fitted model for soil parameters. Results showed that OK was suitable for soil sodium adsorption ratio (SAR) and Na(+) interpolation; UK was suitable for soil Cl(-) and pH; DK was suitable for soil Ca(2+). The nugget-to-sill ratio was applied to evaluate the effects of structural and stochastic factors. The maps showed that the areas of non-saline soil and slight salinity soil accounted for 6.39 and 93.61%, respectively. The spatial distribution and accumulation of soil salt were significantly affected by the irrigation probabilities and drainage situation under long-term wastewater irrigation.

Transcriptional pausing induced by ionizing radiation enables the acquisition of radioresistance in nasopharyngeal carcinoma.

Lesions on the DNA template can impact transcription via distinct regulatory pathways. Ionizing radiation (IR) as the mainstay modality for many malignancies elicits most of the cytotoxicity by inducing a variety of DNA damages in the genome. How the IR treatment alters the transcription cycle and whether it contributes to the development of radioresistance remain poorly understood. Here, we report an increase in the paused RNA polymerase II (RNAPII), as indicated by the phosphorylation at serine 5 residue of its C-terminal domain, in recurrent nasopharyngeal carcinoma (NPC) patient samples after IR treatment and cultured NPC cells developing IR resistance. Reducing the pool of paused RNAPII by either inhibiting TFIIH-associated CDK7 or stimulating the positive transcription elongation factor b, a CDK9-CycT1 heterodimer, attenuates IR resistance of NPC cells. Interestingly, the poly(ADP-ribosyl)ation of CycT1, which disrupts its phase separation, is elevated in the IR-resistant cells. Mutation of the major poly(ADP-ribosyl)ation sites of CycT1 decreases RNAPII pausing and restores IR sensitivity. Genome-wide chromatin immunoprecipitation followed by sequencing analyses reveal that several genes involved in radiation response and cell cycle control are subject to the regulation imposed by the paused RNAPII. Particularly, we identify the NIMA-related kinase NEK7 under such regulation as a new radioresistance factor, whose downregulation results in the increased chromosome instability, enabling the development of IR resistance. Overall, our results highlight a novel link between the alteration in the transcription cycle and the acquisition of IR resistance, opening up new opportunities to increase the efficacy of radiotherapy and thwart radioresistance in NPC.

Effects of irrigation water quality on the presence of pharmaceutical and personal care products in topsoil and vegetables in greenhouses.

The presence of pharmaceutical and personal care products (PPCPs) in the environment has harmful effects on humans and the ecosystem. Reclaimed water irrigation may introduce PPCPs into the agricultural system. Here, a greenhouse experiment investigated the impact of reclaimed water irrigation on PPCP levels in the edible parts of vegetables and topsoil in the North China Plain in 2015 and 2016. Three treatment protocols were applied to each vegetable: irrigation with reclaimed water, irrigation with groundwater, and mixed irrigation with groundwater and reclaimed water (1:1, v/v). The total concentrations of 10 PPCPs in the topsoil (0-20 cm deep) and vegetables were 4.06-19.0 and 2.33-189 µg/kg, respectively. Among the target PPCPs, acetyl-sulfamethoxazole (AC-SMX) had the highest concentration in both soil and vegetables (0.23-10.8 and 1.56-116 µg/kg, respectively). The total concentration of the 10 PPCPs among cabbage, cauliflower, carrot, and cucumber were 13.1-28.1, 10.3-28.3, 2.33-4.04, and 110-189 µg/kg, respectively. The total hazard quotients for the mixture of target PPCPs across all vegetables were 0.0007 and 0.0003 for toddlers and adults, respectively. Compared with groundwater irrigation, reclaimed water irrigation did not evidently affect the vegetable yields, soil-vegetable PPCP concentrations, and BCFs. In this study, we found no potential hazard to human health when people consumed vegetables grown using reclaimed water irrigation.

Metabolic engineering of genome-streamlined strain Pseudomonas putida KTU-U27 for medium-chain-length polyhydroxyalkanoate production from xylose and cellobiose.

Bio-based plastics polyhydroxyalkanoates (PHAs) are considered as a good substitutive to traditional fossil-based plastics because PHAs outcompete chemical plastics in several important properties, such as biodegradability, biocompatibility, and renewability. However, the industrial production of PHA (especially medium-chain-length PHA, mcl-PHA) is greatly restricted by the cost of carbon sources. Currently, xylose and cellobiose derived from lignocellulose are potential substrates for mcl-PHA production. In this study, Pseudomonas putida KTU-U27, a genome-streamlined strain derived from a mcl-PHA producer P. putida KT2440, was used as the optimal chassis for the construction of microbial cell factories with the capacity to efficiently produce mcl-PHA from xylose and cellobiose by introducing the xylose and cellobiose metabolism modules and enhancing the transport of xylose and cellobiose. The lag phases of the xylose- and cellobiose-grown engineered strains were almost completely eliminated and the xylose- and cellobiose-utilizing performance was greatly improved via adaptive laboratory evolution. In shake-flask fermentation, the engineered strain 27A-P13-xylABE-Ptac-tt and 27A-P13-bglC-P13-gts had a mcl-PHA content of 41.67 wt% and 45.18 wt%, respectively, and were able to efficiently utilize xylose or cellobiose as the sole carbon source for cell growth. Herein, microbial production of mcl-PHA using xylose as the sole carbon source has been demonstrated for the first time. Meanwhile, the highest yield of mcl-PHA produced from cellobiose has been obtained in this study. Interestingly, the engineered strains derived from genome-reduced P. putida strains showed higher xylose- and cellobiose-utilizing performance and higher PHA yield than those derived from P. putida KT2440. This study highlights enormous potential of the engineered strains as promising platforms for low-cost production of mcl-PHA from xylose- and cellobiose-rich substrates.

Development of a novel promoter engineering-based strategy for creating an efficient para-nitrophenol-mineralizing bacterium.

A toxic and persistent pollutant para-nitrophenol (PNP) enters into the environment through improper industrial waste treatment and agricultural usage of chemical pesticides, leading to a potential risk to humans. Although a variety of PNP-degrading bacteria have been isolated, their application in bioremediation has been precluded due to unknown biosafety, poor PNP-mineralizing capacity, and lack of genome editing tools. In this study, a novel promoter engineering-based strategy is developed for creating efficient PNP-mineralizing bacteria. Initially, a complete PNP biodegradation pathway from Pseudomonas sp. strain WBC-3 was introduced into the genome of a biosafety and soil-dwelling bacterium Pseudomonas putida KT2440. Subsequently, five strong promoters were identified from P. putida KT2440 by transcriptome analysis and strength characterization, and each of the five promoters was independently inserted into upstream of the pnp operon in the KT2440 genome. Consequently, a P8 promoter-substituted mutant strain showed the highest PNP degradation rate and strong tolerance against high concentrations of PNP. Furthermore, when using P8 promoter to regulate the transcription of all PNP degradation genes pnpABCDEF, the complete and efficient PNP mineralization was demonstrated by stable isotope 13C-labeled PNP transformation assay. Additionally, the finally constructed KTU-P8pnp can be monitored using integrated GFP on chromosome. This strategy of a combination of pathway construction and promoter engineering should open new avenues for creating efficient degraders for bioremediation.

Cropping system exerts stronger influence on antibiotic resistance gene assemblages in greenhouse soils than reclaimed wastewater irrigation.

The effects of reclaimed wastewater (RW) irrigation on the spread of antibiotic resistance genes (ARGs) in soil is modulated by a myriad of biotic and abiotic factors and their relative significance remains vague. We compared microbial communities, assemblages of genes associated with microbial resistance to antibiotics, biocides and metals, and insertion sequences (ISs) in soils following 16 years of irrigation with groundwater (GW), RW or alternately with GW and RW in two greenhouses with different cropping systems, using shotgun metagenome sequencing. The results showed that cropping system exerted greater influence than irrigation on the profile of ISs and resistance genes. This influence was most strongly associated with concentrations of copper, mercury and perfloxacin in the soils. There was no significant difference in soil ARG profiles between continuous RW irrigation and alternating GW and RW irrigation. Proteobacteria, Actinobacteria and Firmicutes and a limited number of ISs were closely associated with the detected ARGs. Most ARGs were found to co-occur with metal and biocide resistance genes through the mechanism of efflux pumps. These findings highlight the significance of understanding and improving crop management in mitigating the dissemination of ARGs in soils irrigated with RW.

A patent and literature review of CDK12 inhibitors.

INTRODUCTION: Cyclin-dependent kinase 12 (CDK12) belongs to the CDK family of serine/threonine protein kinases and is associated with cyclin K to exert its biological functions, including regulating gene transcription, mRNA processing, and translation. Increasing evidences demonstrate the importance of CDK12 in various human cancers, illustrating its potential as both biomarker and therapeutic target. In addition, CDK12 is also a promising target for the treatment of myotonic dystrophy type 1. Efforts have been taken to discover small molecule inhibitors to validate this important therapeutic target. AREAS COVERED: This review covers the patented CDK12 inhibitors from 2016 to present, as well as these from peer-reviewed literature. It provides the reader an update of the discovery strategies, chemical structures, and molecular profiling of all available CDK12 inhibitors. EXPERT OPINION: CDK12 inhibitors with various mechanism of actions have been discovered, and it is a great set of tools to evaluate the therapeutic potential of CDK12 in different disease models. CDK12 inhibitors have shown promising results in myotonic dystrophy type 1 mouse model and several preclinical cancer models either as single agent or combination with other anti-cancer agents. Its therapeutic value awaits more rigorous preclinical testing and further clinical investigation.

Enhanced production of polyhydroxyalkanoates in Pseudomonas putida KT2440 by a combination of genome streamlining and promoter engineering.

Polyhydroxyalkanoates (PHAs), a class of bioplastics produced by a variety of microorganisms, have become the ideal alternatives for oil-derived plastics due to their superior physicochemical and material characteristics. Pseudomonas putida KT2440 can produce medium-chain-length PHA (mcl-PHA) from various substrates. In this study, a novel strategy of the large-scale deletion of genomic islands (GIs) coupling with promoter engineering was developed in P. putida KT2440 for constructing the minimal genome cell factories (MGF) capable of efficiently producing mcl-PHA. Firstly, P. putida KTU-U13, a 13 GIs- and upp-deleted mutant derived from the parental strain P. putida KT2440, was used as a starting strain for further deletion of GIs to generate a series of genome-reduced strains. Subsequently, the two minimal genome strains KTU-U24 and KTU-U27, which had a 7.19% and 8.35% reduction relative to the genome size of KT2440 and were advantageous over the strain KTU (KT2440∆upp) and KTU-U13 in several physiological traits such as the maximum specific growth rate, plasmid transformation efficiency, heterologous protein expression capacity and PHA production capacity, were selected as the chassis cells for PHA metabolic engineering. To prevent the formation of the by-product gluconic acid, the glucose dehydrogenase gene was deleted in KTU-U24 and KTU-U27, resulting in KTU-U24∆gcd and KTU-U27∆gcd. To enhance the transcriptional level of PHA synthase genes (phaC) and the supply of the precursor acetyl-CoA, a strong endogenous promoter P46 was inserted into upstream of the phaC operon and pyruvate dehydrogenase gene in the genome of KTU-U24∆gcd and KTU-U27∆gcd, to generate KTU-U24∆gcd-P46CA and KTU-U27∆gcd-P46CA, with the PHA yield of 50.5 wt% and 53.8 wt% (weight percent of PHA in cell dry weight). Finally, KTU-U27∆gcd-P46CA, the most minimal KT2440 chassis currently available, was able to accumulate the PHA to 55.82 wt% in a 5-l fermentor, which is the highest PHA yield obtained with P. putida KT2440 so far. This study suggests that genome streamlining in combination with promoter engineering may be a feasible strategy for the development of the MGF for the efficient production of high value products. Moreover, further streamlining of the P. putida KT2440 genome has great potential to create the optimal chassis for synthetic biology applications.

ARID1A loss derepresses a group of human endogenous retrovirus-H loci to modulate BRD4-dependent transcription.

Transposable elements (TEs) through evolutionary exaptation have become an integral part of the human genome, offering ample regulatory sequences and shaping chromatin 3D architecture. While the functional impacts of TE-derived sequences on early embryogenesis have been recognized, their roles in malignancy are only starting to emerge. Here we show that many TEs, especially the pluripotency-related human endogenous retrovirus H (HERVH), are abnormally activated in colorectal cancer (CRC) samples. Transcriptional upregulation of HERVH is associated with mutations of several tumor suppressors, particularly ARID1A. Knockout of ARID1A in CRC cells leads to increased transcription at several HERVH loci, which involves compensatory contribution by ARID1B. Suppression of HERVH in CRC cells and patient-derived organoids impairs tumor growth. Mechanistically, HERVH transcripts colocalize with nuclear BRD4 foci, modulating their dynamics and co-regulating many target genes. Altogether, we uncover a critical role for ARID1A in restraining HERVH, whose abnormal activation can promote tumorigenesis by stimulating BRD4-dependent transcription.

Phenols in soils and agricultural products irrigated with reclaimed water.

The presence of phenols, such as nonylphenol (NP), bisphenol (BPA), and octylphenol (OP), in the environment have been receiving increased attention due to their potential risks to human health and environment. The use of reclaimed water for irrigation may be one of the sources of these phenols in the agricultural system. A field experiment was conducted to assess the effects of reclaimed water irrigation on phenol contamination of agricultural topsoil and products in the North China Plain between 2015 and 2016. Three irrigation treatments were applied to all crops: reclaimed water irrigation, groundwater irrigation and alternative irrigation with reclaimed water and groundwater (1:1, v/v). The results showed that the concentrations of NP, BPA, and OP in the topsoil were 0.02-0.54, 0.004-0.06, and ND-9.9 × 10-3 mg/kg, respectively; the corresponding values in agricultural products were 0.007-0.70, 0.004-0.24, and ND-1.08 mg/kg, respectively. The concentration of NP in the topsoil and agricultural products and that of BPA in the agricultural products were all less than the recommended limits. The yields of wheat, maize, vegetables were 4.35-7.08, 1.03-6.46, and 10.9-67.0 t/ha, respectively. The bioaccumulation factors (BCFs) of OP, NP, and BPA for cereals were 0.7-4.77, 0.16-4.59, and 1.3-23.9, respectively; the corresponding values in vegetables were 0.0-4.53 (except cucumber and eggplant), 0.38-12.6, and 0.57-24.3, respectively. No significant differences in phenol concentrations, BCFs, or yields of wheat and vegetables were observed among the three irrigation treatments. In conclusion, compared with groundwater irrigation, reclaimed water irrigation in this experiment did not significantly affect phenol concentrations in the topsoil and agricultural products as well as BCFs and yields of wheat and vegetables. However, because the quality of reclaimed water may vary across collected areas, additional experiments are warranted to analyze the effects of reclaimed water irrigation on the risk of phenol contamination.

New triterpenes from Cimicifuga yunnanensis down-regulating the mRNA expression of CD147, MMP-2, and MMP-9.

Eleven new 9,19-cycloartane triterpenes (1-9, 11-12) and one undescribed lanostane-type aglycone (10) were identified from the aerial parts of Cimicifuga yunnanensis. The new structures were elucidated by analysis of spectroscopic data. Compounds 3-5, 7-9, and 11, without obvious cytotoxicity at 50 µM, were evaluated for inhibiting the mRNA expressions of atherosclerosis-related factors of CD147 (extracellular matrix metalloproteinase inducer, EMMPRIN), matrix metalloproteinase 2 (MMP-2) and MMP-9 in phorbol-12-myristate-13-acetate (PMA) induced Human monocytic THP-1 cells by using a quantitative real-time PCR method (q-PCR). Among them, aglycones 7 and 8 showed potent activities, whereas all tested glycosides were inactive. Compounds 7 and 8 suppressed the mRNA expression of CD147 in a dose-dependent manner, with an IC50 value of 3.38 ± 0.27 µM and 8.25 ± 0.33 µM, respectively. Besides, 7 dose-related down-regulated the mRNA expression of MMP-2, and MMP-9, having an IC50 value of 6.32 ± 0.31 µM and 11.57 ± 0.23 µM, respectively. Meanwhile, 8 at 10 µM reduced the mRNA expression of MMP-2 and MMP-9 by 35% and 25%, respectively. Significantly, the migration ability of the induced THP-1 cells was potently and dose-dependently inhibited by 7, with an IC50 value of 5.87 ± 0.27 µM.

A promoter engineering-based strategy enhances polyhydroxyalkanoate production in Pseudomonas putida KT2440.

Polyhydroxyalkanoate (PHA), a class of biopolyester synthesized by various bacteria, is considered as an alternative to petroleum-based plastics because of its excellent physochemical and material properties. Pseudomonas putida KT2440 can produce medium-chain-length PHA (mcl-PHA) from glucose, fatty acid and glycerol, and its whole-genome sequences and cellular metabolic networks have been intensively researched. In this study, we aim to improve the PHA yield of P. putida KT2440 using a novel promoter engineering-based strategy. Unlike previous studies, endogenous strong promoters screening from P. putida KT2440 instead of synthetic or exogenous promoters was applied to the optimization of PHA biosynthesis pathway. Based on RNA-seq and promoter prediction, 30 putative strong promoters from P. putida KT2440 were identified. Subsequently, the strengths of these promoters were characterized by reporter gene assays. Furthermore, each of 10 strong promoters screened by transcriptional level and GFP fluorescence was independently inserted into upstream of PHA synthase gene (phaC1) on chromosome. As a result, the transcriptional levels of the phaC1 and phaC2 genes in almost all of the promoter-substituted strains were improved, and the relative PHA yields of the three promoter-substituted strains KTU-P1C1, KTU-P46C1 and KTU-P51C1 were improved obviously, reaching 30.62 wt%, 33.24 wt% and 33.29 wt% [the ratio of PHA weight to cell dry weight (CDW)], respectively. By further deletion of the glucose dehydrogenase gene in KTU-P1C1, KTU-P46C1 and KTU-P51C1, the relative PHA yield of the resulting mutant strain KTU-P46C1-∆gcd increased by 5.29% from 33.24% to 38.53%. Finally, by inserting P46 into upstream of pyruvate dehydrogenase gene in the genome of KTU-P46C1-∆gcd, the relative PHA yield and CDW of the resulting strain KTU-P46C1A-∆gcd reached nearly 42 wt% and 4.06 g/l, respectively, which increased by 90% and 40%, respectively, compared with the starting strain KTU. In particular, the absolute PHA yield of KTU-P46C1A-∆gcd reached 1.7 g/l, with a 165% improvement compared with the strain KTU. Herein, we report the highest PHA yield obtained by P. putida KT2440 in shake-flask fermentation to date. We demonstrate for the first time the effectiveness of endogenous strong promoters for improving the PHA yield and biomass of P. putida KT2440. More importantly, our findings highlight great potential of this strategy for enhanced production of secondary metabolites and heterologous proteins in P. putida KT2440.

Phthalate esters (PAEs) in soil and vegetables in solar greenhouses irrigated with reclaimed water.

Phthalate esters (PAEs) in environments have become a public concern due to their harmful impacts on human and environments, and waste/reclaimed water irrigation maybe one of their sources in agricultural soil. A field experiment was setup to analyze the impacts of reclaimed water irrigation on levels of PAEs in vegetables and topsoil in solar greenhouse on the North China Plain during 2015 and 2016. There were 6 varieties of vegetables. For each variety, there were three irrigation treatments, including groundwater irrigation, reclaimed water irrigation, and alternative irrigation with groundwater and reclaimed water (1:1, v/v). The results show that the levels of the 6 PAEs in soil and vegetables varied between 0.73 and 9.48 mg/kg and 1.89 and 6.35 mg/kg, respectively. There were no significant differences for PAE concentrations among these different treatments at each vegetable harvest (p > 0.05). For both soil and vegetable samples, Di-n-butyl phthalate (DnBP) and Di (2-ethylhexyl) phthalate (DEHP) were the most dominant PAEs, with contents of 0.39-4.43 mg/kg and 0.25-6.31 mg/kg, respectively, contributing12.5-74.60% and 21.24-76.48% of the total 6 PAEs, respectively. The contents of DnBP and dimethyl phthalate (DMP) in topsoil were higher than the suggested allowable values, while the concentration of each individual PAE in topsoil was lower than the suggested cleanup objectives. The levels of 6 PAEs, DEHP, and DnBP in vegetables were below the reference doses. The yields of eggplant, cauliflower, bean, cabbage, cucumber, and carrot were 64.4-67.0 t/ha, 10.9-13.0 t/ha, 12.3-15.1 t/ha, 17.3-17.5 t/ha, 43.9-44.5 t/ha, and 19.0-22.9 t/ha, respectively, and no significant differences were found among these different treatments for each kind of vegetable. The bioaccumulation factors (BCFs) of 6 PAEs in vegetable samples were 0.43-5.79 and the corresponding values for each PAE were 0.00-27.32, respectively. The BCFs of butyl benzyl phthalate were the greatest (with a mean of 9.28), followed by DEHP (with a mean of 3.03) and DMP (with a mean of 1.90). In one word, the reclaimed water in this study did not affect the vegetable yields obviously. PAE levels in soil and vegetables irrigated with reclaimed water were in the acceptable range. Considering the difference of reclaimed water quality of Sewage Treatment Plants in different areas, so more reclaimed water from different areas is needed to assess the impacts of reclaimed water irrigation on PAE contamination in soil and vegetables.

Quantitative assessment of groundwater pollution risk in reclaimed water irrigation areas of northern China.

The application of reclaimed water for agricultural irrigation can effectively reduce the use of freshwater resources including groundwater, addressing the increasingly severe challenge of water shortage. However, reclaimed water irrigation will cause potential pollution risks to groundwater, which needs to be further studied to ensure the safety of reclaimed water irrigation. An integrated quantitative assessment system including the modified DRASTIC model was developed to evaluate the pollution risks caused by reclaimed water irrigation and scientific strategies were offered for the development of reclaimed water irrigation in water shortage areas to avoid groundwater pollution. The groundwater intrinsic vulnerability index, the hazards of the characteristic pollutants, and the groundwater values were quantified to obtain the pollution risks distribution map. In the Beijing plain of north China, the low groundwater pollution risk areas were located in the midstream of Chaobai river baisin, Beiyun river basin, and Yongding river basin, accounting for 48.3% of the total study area. These areas in low pollution risk can be considered as safety areas for reclaimed water irrigation. The moderate groundwater pollution risk areas accounting for 46.9% of the total study area were suggested to apply water-saving irrigation measures for preventing groundwater pollution. The reclaimed water irrigation should be prohibited in the high groundwater pollution risk areas, which accounted for 4.8% of the total study area. This study highlights the reasonable strategy for the development of reclaimed water irrigation in water shortage areas and lay a foundation for finding alternative water sources for agricultural irrigation.