Generation of zero-valent sulfur from dissimilatory sulfate reduction in sulfate-reducing microorganisms.

Dissimilatory sulfate reduction (DSR) mediated by sulfate-reducing microorganisms (SRMs) plays a pivotal role in global sulfur, carbon, oxygen, and iron cycles since at least 3.5 billion y ago. The canonical DSR pathway is believed to be sulfate reduction to sulfide. Herein, we report a DSR pathway in phylogenetically diverse SRMs through which zero-valent sulfur (ZVS) is directly generated. We identified that approximately 9% of sulfate reduction was directed toward ZVS with S8 as a predominant product, and the ratio of sulfate-to-ZVS could be changed with SRMs' growth conditions, particularly the medium salinity. Further coculturing experiments and metadata analyses revealed that DSR-derived ZVS supported the growth of various ZVS-metabolizing microorganisms, highlighting this pathway as an essential component of the sulfur biogeochemical cycle.

Jujuboside B alleviates acetaminophen-induced hepatotoxicity in mice by regulating Nrf2-STING signaling pathway.

BACKGROUND: Jujuboside B (JuB) is the main bioactive saponin component of Chinese anti-insomnia herbal medicine Ziziphi Spinosae Semen, which has been reported to possess varied pharmacological functions. Even though it has been traditionally used to treat inflammation- and toxicity-related diseases, the effects of JuB on acetaminophen (APAP) overdose-induced hepatotoxicity have not been determined yet. METHODS: C57BL/6 J mice were pre-treated with JuB (20 or 40 mg/kg) for seven days before APAP (400 mg/kg) injection. After 24 h of APAP treatment, serum, and liver tissues were collected to evaluate the therapeutic effects. To investigate whether the Nrf2-STING signaling pathway is involved in the protective effects of JuB against APAP-induced hepatotoxicity, the mice received the DMXAA (the specific STING agonist) or ML385 (the specific Nrf2 inhibitor) during the administration of JuB, and Hematoxylin-eosin staining, Real-time PCR, immunohistochemical, and western blot were performed. RESULTS: JuB pretreatment reversed APAP-induced CYP2E1 accumulations and alleviated APAP-induced acute liver injury. Furthermore, JuB treatment significantly inhibited oxidative stress and the pro-inflammatory cytokines, as well as alleviated hepatocyte apoptosis induced by APAP. Besides, our result also demonstrated that JuB treatment upregulated the levels of total Nrf2, facilitated its nuclear translocation, upregulated the expression of HO-1 and NQO-1, and inhibited the APAP-induced STING pathway activation. Finally, we verified that the beneficial effects of JuB were weakened by DMXAA and ML385. CONCLUSION: Our study suggested that JuB could ameliorate APAP-induced hepatic damage and verified a previously unrecognized mechanism by which JuB prevented APAP-induced hepatotoxicity through adjusting the Nrf2-STING pathway.

Orthant-symmetric four-dimensional geometric shaping for fiber-optic channels via a nonlinear interference model.

Maximizing the data throughput for optical fiber communication via signal shaping has usually been regarded as challenging due to the nonlinear interference and implementation/optimization complexity. To overcome these challenges, in this paper, we propose an efficient four-dimensional (4D) geometric shaping (GS) approach to design 4D 512-ary and 1024-ary modulation formats by maximizing the generalized mutual information (GMI) using a 4D nonlinear interference (NLI) model, which makes these modulation formats more nonlinear-tolerant. In addition, we propose and evaluate a fast and low-complexity orthant-symmetry based modulation optimization algorithm via neural networks, which allows to improve the optimization speed and GMI performance for both linear and nonlinear fiber transmission systems. The optimized modulation formats with spectral efficiencies of 9 and 10 bit/4D-sym demonstrate a GMI improvement of up to 1.35 dB compared with their quadrature amplitude modulation (QAM) counterparts in additive white Gaussian noise (AWGN) channel. Numerical simulations of optical transmission over two types of fibers show that the 4D NLI model-learned modulation formats could extend the transmission reach by up to 34% and 12% with respect to the QAM formats and the AWGN-learned 4D modulation formats, respectively. Results of effective signal-to-noise ratio are also presented, which confirm that the extra gains in optical fiber channel come from the enhanced SNR by reducing the modulation-dependent NLI.

Unique microbiome in organic matter-polluted urban rivers.

Approximately half of the global annual production of wastewater is released untreated into aquatic environments, which results in worldwide organic matter pollution in urban rivers, especially in highly populated developing countries. Nonetheless, information on microbial community assembly and assembly-driving processes in organic matter-polluted urban rivers remains elusive. In this study, a field study based on water and sediment samples collected from 200 organic matter-polluted urban rivers of 82 cities in China and Indonesia is combined with laboratory water-sediment column experiments. Our findings demonstrate a unique microbiome in these urban rivers. Among the community assembly-regulating factors, both organic matter and geographic conditions play major roles in determining prokaryotic and eukaryotic community assemblies, especially regarding the critical role of organic matter in regulating taxonomic composition. Using a dissimilarity-overlap approach, we found universality in the dynamics of water and sediment community assembly in organic matter-polluted urban rivers, which is distinctively different from patterns in eutrophic and oligotrophic waters. The prokaryotic and eukaryotic communities are dominated by deterministic and stochastic processes, respectively. Interestingly, water prokaryotic communities showed a three-phase cyclic succession of the community assembly process before, during, and after organic matter pollution. Our study provides the first large-scale and comprehensive insight into the prokaryotic and eukaryotic community assembly in organic matter-polluted urban rivers and supports their future sustainable management.

Improve Niche Colonization and Microbial Interactions for Organohalide-Respiring-Bacteria-Mediated Remediation of Chloroethene-Contaminated Sites.

Organohalide-respiring bacteria (OHRB)-mediated reductive dehalogenation is promising in in situ bioremediation of chloroethene-contaminated sites. The bioremediation efficiency of this approach is largely determined by the successful colonization of fastidious OHRB, which is highly dependent on the presence of proper growth niches and microbial interactions. In this study, based on two ecological principles (i.e., Priority Effects and Coexistence Theory), three strategies were developed to enhance niche colonization of OHRB, which were tested both in laboratory experiments and field applications: (i) preinoculation of a niche-preparing culture (NPC, being mainly constituted of fermenting bacteria and methanogens); (ii) staggered fermentation; and (iii) increased inoculation of CE40 (a Dehalococcoides-containing tetrachloroethene-to-ethene dechlorinating enrichment culture). Batch experimental results show significantly higher dechlorination efficiencies, as well as lower concentrations of volatile fatty acids (VFAs) and methane, in experimental sets with staggered fermentation and niche-preconditioning with NPC for 4 days (CE40_NPC-4) relative to control sets. Accordingly, a comparatively higher abundance of Dehalococcoides as major OHRB, together with a lower abundance of fermenting bacteria and methanogens, was observed in CE40_NPC-4 with staggered fermentation, which indicated the balanced syntrophic and competitive interactions between OHRB and other populations for the efficient dechlorination. Further experiments with microbial source tracking analyses suggested enhanced colonization of OHRB by increasing the inoculation ratio of CE40. The optimized conditions for enhanced colonization of OHRB were successfully employed for field bioremediation of trichloroethene (TCE, 0.3-1.4 mM)- and vinyl chloride (VC, ∼0.04 mM)-contaminated sites, resulting in 96.6% TCE and 99.7% VC dechlorination to ethene within 5 and 3 months, respectively. This study provides ecological principles-guided strategies for efficient bioremediation of chloroethene-contaminated sites, which may be also employed for removal of other emerging organohalide pollutants.

PABPN1 functions as a predictive biomarker in colorectal carcinoma.

PURPOSE: PABPN1 acts as a modulator of poly(A) tail length and alternative polyadenylation. This research was aimed to explore the role of PABPN1 in colorectal cancer (CRC). METHODS: Public databases were performed to analyze expression, location, roles of prognosis and tumor immunity and interaction with RNAs and proteins of PABPN1. To investigate PABPN1 expression in tissues, 78 CRC specimens were collected to conduct IHC, and 30 pairs of frozen CRC and corresponding adjacent normal tissues were used to conduct qRT-PCR and WB. In addition, in vitro experiments were then carried out to identify the role of PABPN1 in CRC. RESULTS: Compared with normal tissues, PABPN1 expression was significant higher in CRC. Its high level predicted poor outcome of CRC. Th1 and Treg had significant negative relationships not only with PABPN1 expression, but also with six molecules interacting with PABPN1, including IFT172, KIAA0895L, RECQL4, WDR6, PABPC1 and NCBP1. In addition, PABPN1 had negative relationships with quite a few immune markers, such as CSF1R, IL-10, CCL2 and so on. In cellular experiments, silencing PABPN1 inhibited proliferation and promoted apoptosis in HCT-116 CRC cells. CONCLUSION: In summary, PABPN1 might become a novel biomarker and correlate with tumor immunity in CRC.

Biodiesel production and properties estimation from food waste and domestic wastewater by Rhodosporidium toruloides.

Producing biodiesel from food waste (FW) would benefit both environment and economy. Current study investigated biodiesel production from food waste and domestic wastewater by utilizing the oleaginous yeast Rhodosporidium toruloides under non-sterile condition. The potential of biolipid production from the mixture of effluents of existing local FW treatment facilities and domestic wastewater was firstly evaluated. Then, to increase the nutrient recovery efficiency, FW hydrolysis process by crude enzymes produced from solid FWs by Aspergillus oryzae was introduced and the conditions were further optimized. The optimized hydrolysis process resulted in reducing sugar (RS) yield of 251.81 ± 8.09 mg gdryFW-1 and free amino nitrogen (FAN) yield of 7.70 ± 0.74 mg gdryFW-1 while waste oil with the RS yield of 93.54 ± 0.01 mg gdryFW-1 was easily separated without solvent usage. Compared to the hydrolysate only used, when mixed with domestic wastewater, the results showed obvious enhancement on biomass yield, biolipid yield, and wastewater treatment efficiency. The maximum biolipid yield was 29.80 ± 0.50 mg gdryFW-1 and the estimated quality of biodiesel produced from the biolipid met both EN 14214 and ASTM D6751 standards.

Transmission networks of hepatitis C virus among HIV/HCV-coinfected patients in Guangdong, China.

BACKGROUND: Coinfection with hepatitis C virus (HCV) is common in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients due to shared routes of transmission. We aimed to investigate the characteristics of HCV subgenotypes among HIV/HCV-coinfected patients in Guangdong and explore the molecular transmission networks and related risk factors for HCV strains. METHODS: Plasma samples were obtained from 356 HIV/HCV-coinfected patients for HCV NS5B region sequencing. A neighbor-joining phylogenetic tree was constructed to affirm HCV subgenotypes. The transmission networks based on maximum likelihood phylogenetic tree were determined by Cluster Picker, and visualized using Cytoscape 3.2.1. RESULTS: A total of 302 HCV NS5B sequences were successfully amplified and sequenced from the 356 plasma samples. A neighbor-joining phylogenetic tree based on the 302 NS5B sequences revealed the profile of HCV subgenotypes circulating among HIV/HCV coinfection patients in Guangdong. Two predominant strains were found to be 6a (58.28%, 176/302) and 1b (18.54%, 56/302), followed by 3a (10.93%, 33/302), 3b (6.95%, 21/302), 1a (3.64%, 11/302), 2a (0.99%, 3/302) and 6n (0.66%, 2/302). A molecular transmission network of five major HCV genotypes was constructed, with a clustering rate of 44.04%. The clustering rates of subgenotypes 1a, 3a, 3b, 1b, and 6a were 18.18% (2/11), 42.42%, 52.38%, 48.21%, and 44.89%, respectively. Multivariate logistic regression analysis showed no significant effects from sex, age, transmission route, geographical region, baseline CD4 + T cell count or subgenotype (P > 0.05), except marital status. Married or cohabiting people (compared with unmarried people) had more difficulty forming transmission networks. CONCLUSIONS: In summary, this study, based on HCV NS5B subgenotypes, revealed the HCV subtype diversity and distribution among HIV/HCV-coinfected patients in Guangdong. Marital status inclined to be the factor influencing HCV transmission networks formation.

Preparation of multi-function graphene materials through electrode-distance controlled electrochemical exfoliation.

Preparation of graphene materials with different microstructures is of great significance for the specific applications in various areas. Here, a modified electrochemical exfoliation method with controlled electrode distance is proposed to prepare exfoliated graphene, graphene quantum dots, and graphene oxide (EGr, EGQD, and EGO). Compared with electrolysis at a fixed location, the modified electrode distance can effectively tune the insertion speed and direction, as well as the kinetic rates of exfoliation processes. Specifically, at a short electrode distance of 3 cm, it produced high-quality EGr with the size above 5µm and thickness below 5 layers; when the electrode distance increased to 30 cm, EGQD with the size below 5 nm was produced. Further, the distance between 3 and 30 cm facilitates producing EGO with ca. 15% O content. In addition, it is found that the reaction temperature, optimized electrolyte, and controlled potential can further optimize the exfoliation processes, which can achieve a high exfoliation rate of ca. 2000, 140, and 1500 g h-1for EGr, EGQD, and EGO preparation in an industrial-scale system, respectively. These modified graphene materials can be directly applied in various areas. For example, EGr can act as an effective component to increase one order of the dielectric property of PVDF; EGQD can effectively generate a PL spectrum at ca. 550 nm; EGO can facilely form a conductive and flexible film through self-assembly.

3D porous carbon conductive network with highly dispersed Fe-Nxsites catalysts for oxygen reduction reaction.

Intrinsic activity and reactive numbers are considered two important factors in oxygen reduction reaction (ORR) catalysts. Herein, we report the rational design and synthesis of a strongly coupled hybrid material comprising of FeZn nanoparticles (FeZn NPs) supported by a three-dimensional carbon conductive network (FeZn NPs@3D-CN) for increased ORR performance. Fe-N-C sites can offer high intrinsic activity owing to the unique bonding and oxygen vacancies, and the carbon conductive network facilitating the exposure to active sites, and increasing electron transport. Because of the synergetic effect of the conductive networks containing Fe-N-C and polyaniline, the catalysts exhibited ORR activity in an alkaline medium via a four-electron transfer process. FeZn NPs@3D-CN exhibited outstanding performance with a limited current density (6.2 mA cm-2), the Tafel slope (81.19 mV dec-1), and stability (23 mV negative shift after 2000 cycles), which were superior to those of 20% Pt/C (5.7 mA cm-2, 75.1 mV dec-1, 36 mV negative shift after 2000 cycles). This research highlights the effect of conductive networks expanding pathways and reducing the resistance of mass transport, which is a facile method to generate superior ORR electrocatalysts.

Strong Circularly-Polarized Room-Temperature Phosphorescence from a Feasibly Separable Scaffold of Bidibenzo[b,d]furan with Locked Axial Chirality.

Novel accessible scaffold featuring circularly-polarized room-temperature phosphorescence (RTP) is attractive but challenging. Herein, we report a new feasibly separable bidibenzo[b,d]furan compound with strong circularly-polarized RTP when doping into the rigid polymer matrix. The simple silica-gel column can separate the absolute chiral R-isomer with excellent chiroptical properties. The experimental data reveal that the treated films exhibit an RTP efficiency of 14.8 %, a largest dissymmetric factor of 0.12, and a longest lifetime of 0.56 s under ambient conditions. It is found that reducing the nonradiative decays boosts the intrinsic circularly-polarized RTP emission. The impressive results indicate that the locked axial chirality skeleton endows the potential of achieving superior circularly-polarized emission for the small organic optoelectronic molecules.

5-Fluorouracil enhances the chemosensitivity of gastric cancer to TRAIL via inhibition of the MAPK pathway.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has the ability to selectively trigger cancer cell apoptosis and can be used as a target for tumor therapy. However, gastric cancer cells are usually insensitive to TRAIL so reducing this drug resistance may improve the treatment of gastric cancer. In this study, we used Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) experiments to determine the effects of 5-fluorouracil (5-FU) and TRAIL on the proliferation of gastric cancer cells. An Annexin V/propidium iodide (PI) staining experiment was used to detect apoptosis, and Western blotting was used to analyze the expression levels of apoptosis-related proteins and mitogen-activated protein kinase (MAPK) pathway proteins. The antitumor effects of 5-FU and TRAIL were verified in vivo using a nude mouse tumorigenesis experiment, and a TUNEL assay was performed to evaluate apoptosis in tumor tissue from the nude mice. We found the combination of 5-FU and TRAIL had a greater inhibitory effect on the proliferation of gastric cancer cells than 5-FU or TRAIL alone both in vivo and in vitro. 5-FU enhanced TRAIL-induced gastric cancer cell apoptosis by inactivating the MAPK pathway. Overall, our analysis firstly provided new insights into the role of 5-FU in increasing sensitivity to TRAIL. 5-FU can be used as a sensitizer for TRAIL, and its administration is a potential strategy for the treatment of gastric cancer.

Spatial Distribution, Bioconversion and Ecological Risk of PCBs and PBDEs in the Surface Sediment of Contaminated Urban Rivers: A Nationwide Study in China.

Surface sediments of polluted urban rivers can be a reservoir of hydrophobic persistent organic pollutants (POPs). In this study, we comprehensively assessed the contamination of two groups of POPs, that is, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), in 173 black-odorous urban rivers in China. Spatial distribution of PCBs and PBDEs showed similar patterns but very different contamination levels in surface sediments, that is, average concentrations of 10.73 and 401.16 ng/g dw for the ∑PCBs and ∑PBDEs, respectively. Tetra-/di-CBs and deca-BDE are major PCBs and PBDEs and accounted for 59.11 and 95.11 wt % of the ∑PCBs and ∑PBDEs, respectively. Compared with the persistence of PBDEs, the EF changes of chiral PCBs together with previous cultivation evidence indicated indigenous bioconversion of PCBs in black-odorous urban rivers, particularly the involvement of uncharacterized Dehalococcoidia in PCB dechlorination. Major PCB sources (and their relative contributions) included pigment/painting (25.36%), e-waste (22.92%), metallurgical industry (13.25%), and e-waste/biological degradation process (10.95%). A risk assessment indicated that exposure of resident organisms in urban river sediments to deca-/penta-BDEs could pose a high ecological risk. This study provides the first insight into the contamination, conversion and ecological risk of PCBs and PBDEs in nationwide polluted urban rivers in China.

Sludge digestibility and functionally active microorganisms in methanogenic sludge digesters revealed by E. coli-fed digestion and microbial source tracking.

Methanogenic sludge digestion plays a pivotal role in attenuating and hygienizing the massively-produced waste activated sludge (WAS), which is predominantly composed of microbial cells and extracellular polymeric substances (EPS). The efficient sludge digestion requires a variety of functionally active microorganisms working together closely to convert sludge organic matter into biogas. Nonetheless, the digestion efficiency (or digestibility quantified as carbon removal efficiency) of major sludge constituents (i.e., microbial cells and EPS) and associated functionally active microorganisms in sludge digesters remain elusive. In this study, we identified the digestibility of sludge microbial cells and the associated functionally active microorganisms by using Escherichia coli (E. coli)-fed digestion and microbial source tracking. The average carbon removals in four digesters fed with fresh WAS (WAS-AD), thermal pretreated WAS (Thermal-WAS-AD), E. coli cells (E.coli-AD) and thermal pretreated E. coli cells (Thermal-E.coli-AD) were 30.6 ± 3.4%, 45.8 ± 2.9%, 69.0 ± 3.4% and 68.9 ± 4.6%, respectively. Compared to WAS-AD and Thermal-WAS-AD, the significantly higher carbon removals in E. coli-AD and Thermal-E. coli-AD suggested the remarkably higher digestibility of microbial cells than EPS, and releasing organic matter from EPS might be a rate-limiting step in sludge digestion. Functionally active microorganisms for microbial cell digestion predominantly included fermenters (e.g., Petrimonas and Lentimicrobium), syntrophic acetogens (e.g., Synergistaceae) and methanogens (e.g., Methanosaeta and Methanosarcina). Microbial source tracking estimation showed that the microbial cell-digesting populations accounted for 35.6 ± 9.1% and 70.3 ± 10.1% of total microbial communities in the WAS-AD and Thermal-WAS-AD, respectively. Accordingly, the functionally active microorganisms for digestion of both microbial cells and EPS accounted for 64.5 ± 12.1% and 97.3 ± 2.0% of total digestion sludge microbiome in WAS-AD and Thermal-WAS-AD, respectively. By contrast, feeding WAS-derived microorganisms accounted for 23.2 ± 4.4% and 2.3 ± 1.2% of total microbial communities in the WAS-AD and Thermal-WAS-AD, respectively.

Effect on simultaneous removal of ammonia, nitrate, and phosphorus via advanced stacked assembly biological filter for rural domestic sewage treatment.

The discharge of ammonia-nitrogen (NH3-N), total nitrogen (TN), chemical oxygen demand (COD), and total phosphorus (TP) in rural sewage usually exceeds the Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB18918-2002). Efficient and cost-effective removal of these pollutants cannot be simultaneously realized using conventional rural sewage treatment methods. Thus, an assembled biological filter (D50 × W50 × H113 cm), including a phosphorus removal layer filled with solid polymeric ferric sulfate and alternating aerobic-anaerobic layers, is proposed herein. The aerobic (anerobic) layers were filled with zeolite (zeolite and composite soil) at different intervals. This system was used for the treatment of synthetic sewage having COD: 122.0-227.0 mg/L; NH3-N: 29.1-47.0 mg/L; TN: 28.0-58.0 mg/L; and TP: 2.0-3.8 mg/L. Based on optimal operation conditions (40 L/h reflow rate, without artificial aeration, and 12-h operation cycle), the system showed NH3-N, TN, COD, and TP removal efficiencies of 87.1  ±  8.1, 83.4  ±  7.9, 91.0  ±  9.4, and 80.0  ±  6.4%, respectively. Further, in the pilot-scale test, under the same optimal parameters, the removal efficiencies of NH3-N, TN, COD, and TP were 78.9  ±  8.1, 75.4  ±  7.9, 82  ±  9.4, and 76  ±  6.4%, respectively. Furthermore, in the different functional units of the system, a large number of functional bacteria capable of efficiently facilitating the simultaneous removal of the different pollutants from sewage were identified. Therefore, this proposed system, which complies with current environmental discharge regulations, can be a more sustainable approach for the treatment of unattended rural sewage.

Genome-Centric Metagenomic Insights into the Impact of Alkaline/Acid and Thermal Sludge Pretreatment on the Microbiome in Digestion Sludge.

Pretreatment of waste-activated sludge (WAS) is an effective way to destabilize sludge floc structure and release organic matter for improving sludge digestion efficiency. Nonetheless, information on the impact of WAS pretreatment on digestion sludge microbiomes, as well as mechanistic insights into how sludge pretreatment improves digestion performance, remains elusive. In this study, a genome-centric metagenomic approach was employed to investigate the digestion sludge microbiome in four sludge digesters with different types of feeding sludge: WAS pretreated with 0.25 mol/liter alkaline/acid (APAD), WAS pretreated with 0.8 mol/liter alkaline/acid (HS-APAD), thermally pretreated WAS (thermal-AD), and fresh WAS (control-AD). We retrieved 254 metagenome-assembled genomes (MAGs) to identify the key functional populations involved in the methanogenic digestion process. These MAGs span 28 phyla, including 69 yet-to-be-cultivated lineages, and 30 novel lineages were characterized with metabolic potential associated with hydrolysis and fermentation. Interestingly, functional populations involving carbohydrate digestion were enriched in APAD and HS-APAD, while lineages related to protein and lipid fermentation were enriched in thermal-AD, corroborating the idea that different substrates are released from alkaline/acid and thermal pretreatments. Among the major functional populations (i.e., fermenters, syntrophic acetogens, and methanogens), significant correlations between genome sizes and abundance of the fermenters were observed, particularly in APAD and HS-APAD, which had improved digestion performance.IMPORTANCE Wastewater treatment generates large amounts of waste-activated sludge (WAS), which consists mainly of recalcitrant microbial cells and particulate organic matter. Though WAS pretreatment is an effective way to release sludge organic matter for subsequent digestion, detailed information on the impact of the sludge pretreatment on the digestion sludge microbiome remains scarce. Our study provides unprecedented genome-centric metagenomic insights into how WAS pretreatments change the digestion sludge microbiomes, as well as their metabolic networks. Moreover, digestion sludge microbiomes could be a unique source for exploring microbial dark matter. These results may inform future optimization of methanogenic sludge digestion and resource recovery.

Organohalide-Respiring Bacteria in Polluted Urban Rivers Employ Novel Bifunctional Reductive Dehalogenases to Dechlorinate Polychlorinated Biphenyls and Tetrachloroethene.

Polluted urban river sediments could be a sink of persistent and toxic polychlorinated biphenyls (PCBs) in urban areas and provide desired growth niches for organohalide-respiring bacteria (OHRB). In this study, microcosms were set up with surface sediments of nationwide polluted urban rivers in China, of which 164 cultures could dechlorinate tetrachloroethene (PCE) to dichloroethenes (DCEs) and to vinyl chloride and/or ethene. Further in vivo tests showed extensive PCB dechlorination with different pathways in 135 PCE pregrown cultures. Taking reductive dechlorination of PCB180 (2345-245-CB) as an example, 121 and 14 cultures preferentially removed flanked para- and meta-chlorines, respectively. Strikingly, all in vitro assays with the 135 PCE pregrown cultures showed identical PCB dechlorination pathways with their living cultures, implying the involvement of bifunctional reductive dehalogenases (RDases) to dechlorinate both PCBs and PCE. Further 16S rRNA and RDase gene-based analyses, together with enantioselective dechlorination of chiral PCBs, suggested that Dehalococcoides and Dehalogenimonas in the 135 cultures largely employed distinctively different novel bifunctional RDases to catalyze PCB/PCE dechlorination. Quantitative assessment of the community assembly process with the modified stochasticity ratio (MST) indicated three different stages in enrichment of OHRB. The second stage, as the only one controlled by stochastic processes (MST > 0.5), required extra attention in monitoring community successional patterns to minimize stochastic variance for enriching the PCB/PCE-dechlorinating OHRB.

Characterization and immune function of the thioredoxin-interacting protein (TXNIP) from Litopenaeus vannamei.

The thioredoxin (Trx) system plays essential roles in maintenance and regulation of the redox state of cysteine residues in cellular proteins. The Trx-interacting protein (TXNIP) is a TRX inhibitory protein that works as a negative regulator in the TRX system. The function of TXNIP in invertebrates, in particular in immunity, remains unclear to date. In the current study, a novel TXNIP from Pacific white shrimp Litopenaeus vannamei was identified and characterized and its roles in immune responses was investigated. TXNIP could interact with Trx and inhibit its redox regulatory activity, suggesting that TXNIP was involved in regulation of the cellular redox state in shrimp. The expression of TXNIP was high in the stomach, gill, scape, eyestalk, epithelium, pyloric and muscle and low in the hepatopancreas, intestine, nerve, hemocytes and heart. Stimulations with pathogens white spot syndrome virus (WSSV) and Vibrio parahaemolyticus and immune stimulants poly (I:C) and LPS could significantly increase the expression of TXNIP in vivo. Silencing of TXNIP using RNAi strategy significantly facilitated the infection of V. parahaemolyticus but inhibited the infection of WSSV in shrimp. These indicated that TXNIP could be positively involved in antibacterial responses but negatively involved in antiviral responses in shrimp. Moreover, knockdown of TXNIP in vivo exerted opposite effects on expression of antimicrobial peptides anti-lipopolysaccharide factors and penaeidins and enhanced the phagocytic activity of hemocytes against bacteria. These suggested that TXNIP could play a complex role in regulation of humoral and cellular immune responses in shrimp.

Critical role for the long non-coding RNA AFAP1-AS1 in the proliferation and metastasis of hepatocellular carcinoma.

Increasing evidence has indicated that dysregulation of long non-coding RNAs (lncRNAs) can contribute to the progression and metastasis of human cancer, including HCC. Previous studies have shown that the lncRNA AFAP1-AS1 plays a critical role in cancer. However, the roles of AFAP1-AS1 in HCC remain to be determined. In the present study, AFAP1-AS1 was found to be increased in HCC tissues, and high AFAP1-AS1 expression was associated with tumor size, TNM stage, vascular invasion, and poor prognosis. Silencing of AFAP1-AS1 significantly reduced cell proliferation, clonal growth, cell migration, and invasion and increased apoptosis in vitro. Furthermore, AFAP1-AS1 silencing markedly reduced tumor growth in a murine allograft model in vivo. The results suggested that AFAP1-AS1 is important in HCC development and serves as a therapeutic target of HCC.

The structure and component characteristics of partial nitrification biofilms under autotrophic and heterotrophic conditions.

The differences in the structure and component characteristics of partial nitrification biofilms between autotrophic and heterotrophic conditions were investigated in this work. Three-dimensional excitation-emission matrix fluorescence spectroscopy (EEM), fluorescence staining, and confocal laser scanning microscopy (CLSM) were used to determine differences in the architecture and extracellular polymeric substance (EPS) distribution of the autotrophic and heterotrophic biofilms. Partial nitrification was successfully achieved, and the results demonstrated that an appropriate amount of organic carbon (chemical oxygen demand (COD)/N = 2.6) is advantageous for obtaining better partial nitrification. The final ammoniation and nitrosation rates achieved were 97 and 99 %, respectively. Proteins (PN) and polysaccharides (PS) were dominant in the tightly bound EPS (TB-EPS) of autotrophic and heterotrophic biofilms, with PN/PS ratios of 0.96 and 0.69, respectively. Proteins, lipids, α-D-glucopyranose polysaccharides, and nucleic acids were mostly present within the layers of biofilms, but they were distributed in the upper-middle portion of the autotrophic biofilm and increased with depth from the upper layer in the heterotrophic biofilms.