Protein convertase subtilisin/Kexin type 9 inhibits hepatocellular carcinoma growth by interacting with GSTP1 and suppressing the JNK signaling pathway

Objective:Protein convertase subtilisin/Kexin type 9(PCSK9)has been found to be closely associated with the occurrence and development of numerous tumors.However,the precise role of PCSK9 and its relationship to the development of hepatocellular carcinoma(HCC)remain largely unknown.This study aimed to clarify these issues.Methods:The expression levels of PCSK9 in HCC tissues and HCC cell lines were determined by the quantitative reverse transcription polymerase chain reaction,Western blot,and immunohistochemical analyses,and the effects of PCSK9 expression on HCC cell biological traits were investigated by overexpressing and downregulating PCSK9 expression in vivo and in vitro.Additionally,the mechanism by which PCSK9 mediated dissociation of glutathione S-transferase Pi 1(GSTP1)dimers and phosphorylation of the Jun N-terminal kinase(JNK)pathway components were investigated.Results:PCSK9 expression levels were significantly lower in HCC tissues than in adjacent non-tumor samples.In vivo and in vitro experiments suggested that PCSK9 inhibited HCC cell proliferation and metastasis.Further analysis showed that PCSK9 interacted with GSTP1 and promoted GSTP1 dimer dissociation and JNK signaling pathway inactivation in HCC cells.Moreover,the relationships between PCSK9 protein expressions and clinical outcomes were investigated.The PCSK9-lo group displayed a significantly shorter overall survival(OS;median OS:64.2 months vs.83.2 months;log-rank statistic:4.237;P=0.04)and recurrencefree survival(RFS;median RFS:26.5 months vs.46.6 months;log-rank statistic:10.498;P=0.001)time than the PCSK9-hi group.Conclusions:PCSK9 inhibited HCC cell proliferation,cell cycle progression,and apoptosis by interacting with GSTP1 and suppressing JNK signaling,suggesting that PCSK9 might act as a tumor suppressor and be a therapeutic target in HCC patients.

Ca^(2+)-independent ZmCPK2 is inhibited by Ca^(2+)-dependent ZmCPK17 during drought response in maize

Calcium oscillations are induced by different stresses.Calcium-dependent protein kinases(CDPKs/CPKs)are one major group of the plant calcium decoders that are involved in various processes including drought response.Some CPKs are calcium-independent.Here,we identified ZmCPK2 as a negative regulator of drought resistance by screening an overexpression transgenic maize pool.We found that ZmCPK2 does not bind calcium,and its activity is mainly inhibited during short term abscisic acid(ABA)treatment,and dynamically changed in prolonged treatment.Interestingly,ZmCPK2 interacts with and is inhibited by calcium-dependent ZmCPK17,a positive regulator of drought resistance,which is activated by ABA.ZmCPK17 could prevent the nuclear localization of ZmCPK2 through phosphorylation of ZmCPK2T60.ZmCPK2 interacts with and phosphorylates and activates ZmYAB15,a negative transcriptional factor for drought resistance.Our results suggest that drought stress-induced Ca^(2+)can be decoded directly by ZmCPK17 that inhibits ZmCPK2,thereby promoting plant adaptation to water deficit.

Occurrence of antibiotic resistance genes and bacterial pathogens in water and sediment in urban recreational water

The emergence and prevalence of antibiotic resistance genes(ARGs) and pathogens in the environment are serious global health concern. However, information about the occurrence of ARGs and pathogens in recreational water is still limited. Accordingly, we investigated the occurrence of six ARGs and human pathogens in three recreational lakes, and the correlations between ARGs and one mobile genetic element(intI1) were analyzed. The quantitative PCR results showed that the concentration of ARGs ranged from 4.58 × 10~0 to 5.0 × 10~5 copies/mL in water and from 5.78 × 10~3 to 5.89 × 10~8 copies/g dry weight(dw)in sediment. Sul1 exhibited the highest level among the five quantifiable ARGs. The concentrations of sul1, bla_(-TEM), and tetX exhibited significant positive correlations with intI1(p < 0.05), indicating that intI1 may be involved in their proliferation. The detection frequencies of ARGs ranged from 75%–10~0%, indicating the prevalence of these risks in this region. The concentration of Escherichia coli, Aeromonas spp., Mycobacterium avium,Pseudomonas aeruginosa, and Salmonella enterica ranged from 10~3 to 10~5 copies/10~0 mL in water and 10~4–10~6 copies/g dw in sediment. In total, 25% of the samples harbored all pathogen genes, indicating the prevalence of these pathogens in recreational lakes.Furthermore, the next-generation sequencing results showed that 68 genera of pathogens were present, among which Aeromonas, Mycobacterium, and Pseudomonas were the dominant ones in this region, posing a considerable potential health risk to public health. Overall, the widespread distribution of ARGs and pathogens underscores the need to better monitor and mitigate their propagation in recreational lakes and the associated risks to human health.

Arginine, N-carbamylglutamate,and glutamine exert protective effects against oxidative stress in rat intestine

The objective of the current study is to evaluate the effects of dietary supplementation with arginine(ARG), N-carbamylglutamate(NCG), and glutamine(GLN) on rat intestinal morphology and antioxidant status under oxidative stress. Rats were fed for 30 d with one of the following iso-nitrogenous diets:basal diet(BD), BD plus 1% ARG, BD plus 0.1% NCG, and BD plus 1% GLN. On day 28, half of the rats fed BD were intraperitoneally injected with 12 mg/kg body weight of diquat(DT; i.e., the DT group) and the other half was intraperitoneally injected with sterile solution(i,e., the control group). The other diet groups were intraperitoneally injected with 12 mg/kg body weight of DT(i,e., DT + 1% GLN [DT + GLN],DT + 1% ARG [DT + ARG], and DT + 0.1% NCG [DT + NCG]). Rat jejunum samples obtained at 48 h after DT injection were analyzed. Results showed that DT significantly decreased catalase(CAT) activity and glutathione(GSH) content by 58.25% and 56.57%, respectively, and elevated malondialdehyde(MDA)content and crypt depth(CD) by 19.39% and 22.13%, respectively, in the jejunum(P < 0.05, relative to the control group). Compared with the DT group, the DT + GLN group exhibited significantly improved villus height(VH), villus width(VW), villus surface area(VSA), CD and total antioxidant capacity(T-AOC) activity(P < 0.05); the DT + ARG group exhibited significantly increased the ratio of VH to CD(H:D) and TAOC activity(P < 0.05); the DT + GLN, DT + ARG and DT + NCG groups exhibited significantly enhanced CAT activity and GSH content as well as decreased MDA content(P < 0.05). Moreover, VH, VW, VSA, CD and GSH content in the DT + GLN group were higher whereas MDA content was lower compared with the corresponding values observed in both the DT + ARG and the DT + NCG groups(P < 0.05). The H:D ratio in the DT + ARG group significantly increased compared with that in the DT + NCG and DT + GLN groups(P < 0.05). Collectively, this study suggested that dietary supplementation with 1% GLN, 0.1% NCG,and 1% ARG was effective in enhancing the antioxidant status and maintaining the morphological structure of rat jejunum under oxidative stress; of these supplements, 1% GLN exerted the greatest effects on mitigating oxidative stress.

Molecular characterization of methanogenic microbial communities for degrading various types of polycyclic aromatic hydrocarbon

Knowledge on methanogenic microbial communities associated with the degradation of polycyclic aromatic hydrocarbons(PAHs)is crucial to developing strategies for PAHs bioremediation.In this study,the linkage between the type of PAHs and microbial community structure was fully investigated through 16 S rRNA gene sequencing on four PAH-degrading cultures.Putative degradation products were also detected.Our results indicated that naphthalene(Nap)/2-methylnaphthalene(2-Nap),phenanthrene(Phe)and anthracene(Ant)sculpted different microbial communities.Among them,Nap and 2-Nap selected for similar degrading bacteria(i.e.,Alicycliphilus and Thauera)and methanogens(Methanomethylovorans and Methanobacterium).Nap and 2-Nap were probably activated via carboxylation,producing 2-naphthoic acid.In contrast,Phe and Ant shaped different bacterial and archaeal communities,with Arcobacter and Acinetobacter being Phe-degraders and Thiobacillus Ant-degrader.Methanogenic archaea Methanobacterium and Methanomethylovorans predominated Phe-degrading and Ant-degrading culture,respectively.These findings can improve our understanding of natural PAHs attenuation and provide some guidance for PAHs bioremediation in methanogenic environment.

Effects of spermine supplementation on the morphology, digestive enzyme activities, and antioxidant capacity of intestine in weaning rats

The main objective of this study was to investigate the effects of different doses of spermine and its extended supplementation on the morphology, digestive enzyme activities, and intestinal antioxidant capacity in weaning rats. Nineteen-day-old male rats received intragastric spermine at doses of 0.2 and0.4 μmol/g BW for 3 or 7 d, whereas control rats received similar doses of saline. The results are as follows: 1) In the jejunum, the seven-day supplementation with both doses of spermine significantly increased crypt depth(P < 0.05) compared with the control group; the supplementation extension of the high spermine dose increased villus height and crypt depth(P < 0.05); in the ileum, the low spermine dose significantly increased villus height and crypt depth compared with the control group for 7 days(P < 0.05). 2) The 3-day supplementation with high spermine dose increased alkaline phosphatase activity in the jejunum(P < 0.05). 3) In the jejunum, the anti-hydroxyl radical(AHR), total superoxide dismutase(T-SOD), catalase(CAT), and total antioxidant capacity(T-AOC) activities were increased(P < 0.05); however, the malondialdehyde(MDA) content was reduced(P < 0.05) in groups supplemented with the high spermine dose relative to those in the control groups after 3 and 7 d; moreover, the anti-superoxide anion(ASA) and glutathione(GSH) contents increased with the high spermine dose that lasted for 3 days(P < 0.05). Furthermore, the T-SOD and CAT activities(after 3 and 7 d), ASA(after 3 d),and AHR(after 7 d) increased with the high spermine dose compared with those of the low spermine dose(P < 0.05). Extending the supplementation duration(7 d) of the high spermine dose decreased the MDA content and ASA and T-AOC activities(P < 0.05). These results suggested that spermine supplementation can modulate gut development and enhance the antioxidant status of the jejunum in weaning rats, and a dosage of 0.4 μmol spermine/g BW had better effects than the dosage of 0.2 μmol spermine/g BW on accelerating gut development and increasing antioxidant capacity.

Evaluation of bacterial pathogen diversity,abundance and health risks in urban recreational water by amplicon next-generation sequencing and quantitative PCR

The microbial quality of urban recreational water is of great concern to public health.The monitoring of indicator organisms and several pathogens alone is not sufficient to accurately and comprehensively identify microbial risks.To assess the levels of bacterial pathogens and health risks in urban recreational water,we analyzed pathogen diversity and quantified four pathogens in 46 water samples collected from waterbodies in Beijing Olympic Forest Park in one year.The pathogen diversity revealed by 16 S r RNA gene targeted next-generation sequencing（NGS） showed that 16 of 40 genera and 13 of 76 reference species were present.The most abundant species were Acinetobacter johnsonii,Mycobacterium avium and Aeromonas spp.Quantitative polymerase chain reaction（q PCR） of Escherichia coli（uid A）,Aeromonas（aer A）,M.avium（16S r RNA）,Pseudomonas aeruginosa（oaa） and Salmonella（inv A） showed that the aer A genes were the most abundant,occurring in all samples with concentrations of 10^（4–6） genome copies/100 m L,followed by oaa,inv A and M.avium.In total,34.8% of the samples harbored all genes,indicating the prevalence of these pathogens in this recreational waterbody.Based on the q PCR results,a quantitative microbial risk assessment（QMRA） showed that the annual infection risks of Salmonella,M.avium and P.aeruginosa in five activities were mostly greater than the U.S.EPA risk limit for recreational contacts,and children playing with water may be exposed to the greatest infection risk.Our findings provide a comprehensive understanding of bacterial pathogen diversity and pathogen abundance in urban recreational water by applying both NGS and q PCR.

Effect of salinity on community structure and naphthalene dioxygenase gene diversity of a halophilic bacterial consortium

The aim of this study is to analyze the effect of salinity on polycyclic aromatic hydrocarbons （PAHs） biodegradation, community structure and naphthalene dioxygenase gene （ndo） diversity of a halophilic bacterial consortium with the denaturing gradient gel electrophoresis （DGGE） approach. The consortium was developed from oil-contaminated saline soil after enrichment for six times, using phenanthrene as the substrate. The prominent species in the bacterial consortium at all salinities were identified as halophilic bacteria Halomonas, Alcanivorax, Marinobacter, Idiomarina, Martelella and uncultured bacteria. The predominant microbes gradually changed associating with the saline concentration fluctuations ranging from 0.1% to 25% （w/v）. Two ndo alpha subunits were dominant at salinities ranging, from 0.1% to 20%. while not been clearly detected at 25% salinity. Consistently. the biodegradation occurred at salmltles rangmg from 0.1% to 20%, while no at 25% salinity, suggesting the two ndo genes played an important role in the degradation. The phylogenetic analysis revealed that both of the two ndo alpha subunits were related to the classic nab-like gene from Pseudomonas stutzeri AN10 and Pseudomonas aeruginosa PaK1, while one with identity of about 82% and the other one with identity of 90% at amino acid sequence level. We concluded that salinity greatly affected halophilic bacterial community structure and also the functional genes which were more related to biodegradation.

Insights into effects of algae on decay and distribution of bacterial pathogens in recreational water:Implications for microbial risk management

The decay and distribution of bacterial pathogens in water is an important information for the health risk assessment to guide water safety management, and suspended algae might affect bacterial pathogens in water. This study established microcosms to investigate the effects of algae-related factors on the representative indicators and opportunistic pathogen species in water. We found that suspended algae increased the persistence of targeted species by 1-2 orders of magnitude of concentrations compared to microcosms without algae;and the effect of algae on microbial survival was affected by water nutrient levels(i.e., carbon, nitrogen and phosphorus), as the increased microbial persistence were correlated to the increased algae concentrations with more nutrient supplies. Moreover, decay and distribution profiles of representative species were determined. The three opportunistic pathogen species( Pseudomonas aeruginosa, Aeromonas hydrophila and Staphylococcus aureus) showed lower decay rates(0.82–0.98/day, 0.76–0.98/day, 0.63–0.87/day) largely affected by algae-related factors, while the enteric species( Escherichia coli and Enterococcus faecalis) had higher decay rates(0.94–1.31/day, 0.89–1.21/day) with little association with algae, indicating the propensity for attachment to algae is an important parameter in microbial fate. Together results suggest suspended algae played an evident role in the decay and distribution of bacterial pathogens, providing important implications regarding microbial safety in recreational water.

Superior performance for lithium storage from an integrated composite anode consisting of SiO-based active material and current collector

Silicon-based material is considered to be one of the most promising anodes for the next-generation lithium-ion batteries(LIBs)due to its rich sources,nontoxicity,low cost and high theoretical specific capacity.However,it cannot maintain a stable electrode structure during repeated charge/discharge cycles,and therefore long cycling life is difficult to be achieved.To address this problem,herein a simple and efficient method is developed for the fabrication of an integrated composite anode consisting of SiO-based active material and current collector,which exhibits a core-shell structure with nitrogen-doped carbon coating on SiO/P micro-particles.Without binder and conductive agent,the volume expansion of SiO active material in the integrated composite anode is suppressed to prevent its pulverization.At a current density of 500 mA·g−1,this integrated composite anode exhibits a reversible specific capacity of 458 mA·h·g−1 after 200 cycles.Furthermore,superior rate performance and cycling stability are also achieved.This work illustrates a potential method for the fabrication of integrated composite anodes with superior electrochemical properties for high-performance LIBs.