THE EXPRESSIONS OF HBV X GENE AND ets-2, IGF-Ⅰ, c-myc AND N-ras ONCOGENES IN HUMAN HEPATOCELLULAR CARCINOMA AND TUMOR-ADJACENT TISSUES

The expressions of HBV X gene and ets-2, IGF-I, c-myc and N-ras were studied in 7 pairs of human primary hepatocellular carcinoma (PHC) and tumor-adjacent tissues, using RNA hybridization and im-munoblot methods. The results showed that specific 17 and 28 kD HBV X gene products (HBxAg) were existed in a portion of PHC and tumor-adjacent tissues. The 17 kD HBxAg was detected in the sera of 3 patients who also had 17 kD HBxAg in their liver tissues. Multiple expressions of oncogenes such as ets-2, c-myc and N-ras were observed in PHC and tumor-adjacent tissues that had HBxAg expressed, indicating HBxAg might function as a transactivator in the course of intracellular proto-oncogene activation. It is also observed that in some tumor-adjacnet tissues the expressions of ets-2, c-myc and N-ras were higher than those in corresponding PHC. The relationship of HBxAg to the expression of est-2, IGF-Ⅱ, c-myc and their possible roles in the carcinogenesis of PHC are discussed.

Promoter hypermethylation of tissue specific tumor supressor genes and point mutation in K-ras, c-myc proto-oncogenes in urinary (transitional cell) bladder carcinoma

In a total of 83 UN specimens were investigated for proto-oncogene mutations, tumor supressor genes promoter methylation status and c-myc and Ki-67 expression. Point mutations in c-myc were detected in cases with high grade and proliferation index. Mutated K-ras proto-onco- gene profiles were detected in 17 (21%) tumoral spiecemens that examined. Tumor specimens were also showed hypermethylated promoter domain for the SFRP2, MGMT tumor supressor genes. These findings showed the combine effect of mutated c-myc and K-ras oncogene and epigenetic inactivation of tissue specific tumor supressor genes (TS) play a crucial role in tumor progression and recurrence in UN carcinogenesis.

β-catenin up-regulates the expression of cyclinD1, c-myc and MMP-7 in human pancreatic cancer: Relationships with carcinogenesis and metastasis

AIM:To investigate whether abnormal expression of β-catenin in conjunction with overexpression of cyclinD1, c-myc and matrix metalloproteinase-7 (MMP-7) correlated with the carcinogenesis, metastasis and prognosis of pancreatic cancer, and to analyze the relationship of β-catenin expression with cyclinDl, c-myc and MMP-7 expression. METHODS: Using immunohistochemistry,we examined the expression of β-catenin, cyclinD1,c-myc and MMP-7 in 47 pancreatic adenocarcinoma tissues, 12 pancreatic intraepithelial neoplasia (PanIN) and 10 normal pancreases, respectively. Proliferation cell nuclear antigen was also tested as the index of proliferative activity of pancreatic cancer cells. RESULTS: In 10 cases of normal pancreatic tissues, epithelial cells showed equally strong membranous expression of β-catenin protein at the cell-cell boundaries, but the expression of cyclinDl, c-myc and MMP-7 was negative. The expression of β-catenin, cyclinD1, c-myc and MMP-7 in PanIN and pancreatic adenocarcinoma tissues had no significant difference [6/12 and 32/47 (68.1%), 6/12 and 35/47 (74.5%), 5/12 and 33/47 (70.2%), 7/12 and 30/47 (63.8%), respectively]. The abnormal expression of β-catenin was significantly correlated to metastasis and one-year survival rate of pancreatic cancer, but had no relation with size, differentiation and cell proliferation. The expression of cyclinD1 was correlated with cell proliferation and extent of differentiation, but not with size, metastasis and one-year survival rate of the pancreatic cancer. The expression of c-myc was not correlated with size, extent of differentiation, metastasis and 1-year survival rate, but closely with cell proliferation of pancreatic cancer. The overexpression of MMP-7 was significantly associated with metastasis and 1-year survival rate of pancreatic cancer,but not with size, extent of differentiation and cell proliferation.There was a highly significant positive association between abnormal expression of β-catenin and overexpression of cyclinD1, c-myc and MMP-7 not only in PanIN (r= 1.000, 0.845, 0.845), but also in pancreatic cancer (r= 0.437, 0.452, 0.435). CONCLUSION: The abnormal expression of β-catenin plays a key role in the carcinogenesis and progression of human pancreatic carcinoma by up-regulating the expression of cyclinDl, c-myc and MMP-7, resulting in the degradation of extracellular matrix and uncontrolled cell proliferation and differentiation,β-catenin abnormal expression and MMP-7 overexpression may be considered as two useful markers for determining metastasis and prognosis of human pancreatic cancer.

INCREASED EXPRESSION OF PDGF AND C-MYC GENES IN LUNGS AND PULMONARY ARTERIES OF PULMONARY HYPERTENSIVE RATS INDUCED BY HYPOXIA

The role of growth factors and proto-oncogene in pulmonary vascular structural remodelling is not well known.The present study examined gene expression of platelet-derived growth factor(PDGF)-A and -B chain and proto-oncogene,c-myc,in lung tissue and pulmonary artery of rats exposed to hypoxia and compared to those levels of gene expression in normal rats.Normal lungs and pulmonary artery expressed PDGF-A chain transcript of 1.7 kb and PDGF-B chain transcript of 3.5 Kb.The c-myc transcript of 2.2 kb was expressed as well. After hypoxic exposure for 7 and 14 days mRNA levels of PDGF-B chain and cmyc were elevated significantly compared with those of control rats.PDGF-A chain mRNA increased after hypoxia for 7 days,and then declined.These results suggest that activation of autocrine and/or paracrine is important in proliferation mechanism of pulmonary artery smooth muscle cells in hypoxic pulmonary hypertensive rats.

Expression of p53 and C-myc genes and its clinical relevance in the hepatocellular carcinomatous and pericarcinomatous tissues

AIM: To investigate the possible roles of p53 and C-mycgenes in the primary hepatocellular carcinogenesis and therelationship between the liver hyperplastic nodule(LHN) andhepatocellular carcinoma(HCC).METHODS: The expression of p53 and C-myc genes wasdetected immunohist-ochemically in 73 and 60 cases of HCCand pericarcinomatous tissues, respectively .RESULTS: The positive expression of p53 in HCC wassignificantly higher than that in pericarcinomatous tissues(P＜0.05). In pericarcinomatous tissues, the p53 expressionwas observed only in LHN, but not in liver cirrhosis (LC) andnormal liver tissues. The positive expression rate of C-mycin HCC or LHN was significantly higher than that in LC ornormal liver tissues (P＜0.05 and P＜0.01), however, nosignificant difference was found between HCC and LHN(P＞0.05). The positive expression rate of p53 and C-myc inHCC was correlated with the histological differentiation, thatin the poorly differentiated was significantly higher than thatin well differentiated samples (P＜0.05).CONCLUSION: The overexpression of p53 and C-myc genesmight play a role in the carcinogenesis of HCC; And LHNseems a preneoplastic lesion related to hepatocarcinogenesis;No evidence supports that LC contribute directly to thehepatocarcinogenesis.

Distribution of oval cells and c-myc mRNA expression in mouse hepatocarcinogenesis

BACKGROUND: This study was designed to assess theroles of oval cells and c-myc mRNA in the process of hepa-tocarcinogenesis and to clarify the function of carcinogenec-myc in the development of hepatocellular carcinoma( HCC) and the mechanism of inhibitory function of uscha-ridin on HCC in mouse hepatocarcinogenesis.METHODS: A total of 120 clean SD mice were divided intonormal group, cancer induction group, and interventiongroup. The normal group was fed with standard foragewhile the rest two groups were given p-dimethylaminoazo-benzene (DAB) to induce cancer. Thirteen weeks after in-duction of cancer, the two groups were fed with standardforage and water. Once the pattern was set up, the inter-vention group was given uscharidin injection into the ab-dominal cavity from the first week to the 14th week. Onthe 2nd, 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, 20th,22nd, and 24th week, all mice were killed and biopsiedfrom the liver lobe for pathological analysis. At the sametime, the number of tumor nodes was counted and the ex-pression of c-myc mRNA was tested by RT-PCR.RESULTS: Since the 2nd week after cancer induction, pro-liferated oval cells could be seen in the portal area. Initially,the oval cells appeared in the cortical layer of the portalarea, then proliferated gradually and immigrated into theliver parenchyma. In the period of fibrosis after liver proli-feration, proliferated heaps of oval cells were noted in bothportal and peripheral areas. In the period of carcinomatouschange, oval cells could be seen both outside and inside ofcancer nodes, but most of them were distributed outside.The c-myc gene was expressed negatively in the liver tissueof mice. The quantity of the expression began to increaseat the time of infection of the liver and tended to increasewith the degree of hepatic injury. In the period of cancera-tion, the expression level of c-myc mRNA increased gra-dually. The intervention of uscharidin could not inhibit butdelay the increase of the expression of c-myc mRNA.CONCLUSION: Oval cells are closely related to hepatocar-cinoma cells, which play an important role in the occur-rence and development of hepatocarcinogenesis. Uschari-din can inhibit the occurrence of hepatocarcinogenesis orlocal spreading at the early stage of cancer induction byDAB, but it cannot inhibit the expression of c-myc.

Expressions of oncogenes c-fos and c-myc in skin lesion of cutaneous squamous cell carcinoma

Objective:To explore the expressions of c-fos and c-myc in skin lesion of cutaneous squamous cell carcinoma(CSCC).Methods:Using retrospective analysis.73 cases of CSCC were selected from Department of Dermatology,the Second Affiliated Hospital of Xi'an Jiaotong University.which were removed between January 2000 and January 2012.It was considered as experimental group.Meanwhile.11 cases of normal skin specimens of non tumor patients were selected as control group.The expression level of c-fos and c-myc was compared in the two groups.Results:The expressions of c-fos[72.60%(53/73)]and c-myc[83.56%(61/73)]in experimental group were statistically significant(P≤0.05)compared with control group(0%).Expression of c-myc protein was negatively related to differentiation of CSCC.The difference was statistically significant(X^2=7.26.P=0.001<0.05).While expression of c-fos protein was positively related to differentiation of CSCC.which was statistically significant(X^2=7.47,P=0.0012<0.025).Conclusions:The expression level of c-fos and c-myc can be used as an importan indicator of CSCC differentiation,and it has closely connection with the differentiated degree,which can guide clinical prognosis.

The Synergistic Effects Study of C-myc and C-erbB-2 in the Carcinogenesis of Gastric Carcinoma

Objective: To study the significance of c-myc and c-erbB-2 oncogene expression in gastric cancer. Methods: 81 gastric cancer specimens were detected for c-myc and c-erbB-2 oncogene amplification using non-radioactive in situ hybridization method. Results: The amplification rates for c-myc and c-erbB-2 were 67.9% and 50.6% respectively, and there were significant correlation in the amplification of these two genes (χ2 = 7.26, P Conclusions: The amplification of c-myc and c-erbB-2 may play an important role in gastric cancer development, and these two genes may have synergistic effect.

Correlation of c-Myc and PIK3R3 expression with invasion and migration genes in melanoma tissue

Objective:To study the correlation of c-Myc and PIK3R3 expression with invasion and migration genes in melanoma tissue.Methods: Surgical removed melanoma tissue and normal skin tissue left in full-thickness skin grafting in 95 Clinical Department, Fuzhou General Hospital between May 2015 and March 2017 were selected, the RNA in the tissue was separated and extracted, and then fluorescence quantitative PCR kit was used to determine the mRNA expression of c-Myc and PIK3R3 as well as invasion and migration genes.Results:c-Myc, PIK3R3, CXCL12, CXCR4, CXCR7, NRP1, MMP2, MMP9 and CatK mRNA expression in melanoma tissue were significantly higher than those in normal skin tissue while E-cadherin, TIMP1 and KISS1 mRNA expression were significantly lower than those in normal skin tissue;c-Myc mRNA expression in melanoma tissue was positively correlated with PIK3R3 mRNA expression;CXCL12, CXCR4, CXCR7, NRP1, MMP2, MMP9 and CatK mRNA expression in melanoma tissue with higher c-Myc expression were significantly higher than those in melanoma tissue with lower c-Myc expression while E-cadherin, TIMP1 and KISS1 mRNA expression were significantly lower than those in melanoma tissue with lower c-Myc expression.Conclusion:The high expression of c-Myc and PIK3R3 in melanoma tissue can promote the invasion and migration of cancer cells.

Comprehensive analysis of the potential pathogenesis of COVID-19 infection and liver cancer

BACKGROUND A growing number of clinical examples suggest that coronavirus disease 2019(COVID-19)appears to have an impact on the treatment of patients with liver cancer compared to the normal population,and the prevalence of COVID-19 is significantly higher in patients with liver cancer.However,this mechanism of action has not been clarified.Gene sets for COVID-19(GSE180226)and liver cancer(GSE87630)were obtained from the Gene Expression Omnibus database.After identifying the common differentially expressed genes(DEGs)of COVID-19 and liver cancer,functional enrichment analysis,protein-protein interaction network construction and scree-ning and analysis of hub genes were performed.Subsequently,the validation of the differential expression of hub genes in the disease was performed and the regulatory network of transcription factors and hub genes was constructed.RESULTS Of 518 common DEGs were obtained by screening for functional analysis.Fifteen hub genes including aurora kinase B,cyclin B2,cell division cycle 20,cell division cycle associated 8,nucleolar and spindle associated protein 1,etc.,were further identified from DEGs using the“cytoHubba”plugin.Functional enrichment analysis of hub genes showed that these hub genes are associated with P53 signalling pathway regulation,cell cycle and other functions,and they may serve as potential molecular markers for COVID-19 and liver cancer.Finally,we selected 10 of the hub genes for in vitro expression validation in liver cancer cells.CONCLUSION Our study reveals a common pathogenesis of liver cancer and COVID-19.These common pathways and key genes may provide new ideas for further mechanistic studies.

Dysregulation of genes involved in the long-chain fatty acid transport in pancreatic ductal adenocarcinoma

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is an aggressive lethal malignancy with limited options for treatment and a 5-year survival rate of 11%in the United States.As for other types of tumors,such as colorectal cancer,aberrant de novo lipid synthesis and reprogrammed lipid metabolism have been suggested to be associated with PDAC development and progression.AIM To identify the possible involvement of lipid metabolism in PDAC by analyzing in tumoral and non-tumoral tissues the expression level of the most relevant genes involved in the long-chain fatty acid(FA)import into cell.METHODS A gene expression analysis of FASN,CD36,SLC27A1,SLC27A2,SLC27A3,SLC27A4,SLC27A5,ACSL1,and ACSL3 was performed by qRT-PCR in 24 tumoral PDAC tissues and 11 samples from non-tumoral pancreatic tissues obtained via fine needle aspiration or via surgical resection.The genes were considered significantly dysregulated between the groups when the p value was<0.05 and the fold change(FC)was≤0.5 and≥2.RESULTS We found that three FA transporters and two long-chain acyl-CoA synthetases genes were significantly upregulated in the PDAC tissue compared to the non-tumoral tissue:SLC27A2(FC=5.66;P=0.033),SLC27A3(FC=2.68;P=0.040),SLC27A4(FC=3.13;P=0.033),ACSL1(FC=4.10;P<0.001),and ACSL3(FC=2.67;P=0.012).We further investigated any possible association between the levels of the analyzed mRNAs and the specific characteristics of the tumors,including the anatomic location,the lymph node involvement,and the presence of metastasis.A significant difference in the expression of SLC27A3(FC=3.28;P=0.040)was found comparing patients with and without lymph nodes involvement with an overexpression of this transcript in 17 patients presenting tumoral cells in the lymph nodes.CONCLUSION Despite the low number of patients analyzed,these preliminary results seem to be promising.Addressing lipid metabolism through a broad strategy could be a beneficial way to treat this malignancy.Future in vitro and in vivo studies on these genes may offer important insights into the mechanisms linking PDAC with the long-chain FA import pathway.

Identification of hub genes associated with Helicobacter pylori infection and type 2 diabetes mellitus:A pilot bioinformatics study

BACKGROUND Helicobacter pylori(H.pylori)infection is related to various extragastric diseases including type 2 diabetes mellitus(T2DM).However,the possible mechanisms connecting H.pylori infection and T2DM remain unknown.AIM To explore potential molecular connections between H.pylori infection and T2DM.METHODS We extracted gene expression arrays from three online datasets(GSE60427,GSE27411 and GSE115601).Differentially expressed genes(DEGs)commonly present in patients with H.pylori infection and T2DM were identified.Hub genes were validated using human gastric biopsy samples.Correlations between hub genes and immune cell infiltration,miRNAs,and transcription factors(TFs)were further analyzed.RESULTS A total of 67 DEGs were commonly presented in patients with H.pylori infection and T2DM.Five significantly upregulated hub genes,including TLR4,ITGAM,C5AR1,FCER1G,and FCGR2A,were finally identified,all of which are closely related to immune cell infiltration.The gene-miRNA analysis detected 13 miRNAs with at least two gene cross-links.TF-gene interaction networks showed that TLR4 was coregulated by 26 TFs,the largest number of TFs among the 5 hub genes.CONCLUSION We identified five hub genes that may have molecular connections between H.pylori infection and T2DM.This study provides new insights into the pathogenesis of H.pylori-induced onset of T2DM.

Key genes and regulatory networks for diabetic retinopathy based on hypoxia-related genes:a bioinformatics analysis

AIM:To prevent neovascularization in diabetic retinopathy(DR)patients and partially control disease progression.METHODS:Hypoxia-related differentially expressed genes(DEGs)were identified from the GSE60436 and GSE102485 datasets,followed by gene ontology(GO)functional annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis.Potential candidate drugs were screened using the CMap database.Subsequently,a protein-protein interaction(PPI)network was constructed to identify hypoxia-related hub genes.A nomogram was generated using the rms R package,and the correlation of hub genes was analyzed using the Hmisc R package.The clinical significance of hub genes was validated by comparing their expression levels between disease and normal groups and constructing receiver operating characteristic curve(ROC)curves.Finally,a hypoxia-related miRNA-transcription factor(TF)-Hub gene network was constructed using the NetworkAnalyst online tool.RESULTS:Totally 48 hypoxia-related DEGs and screened 10 potential candidate drugs with interaction relationships to upregulated hypoxia-related genes were identified,such as ruxolitinib,meprylcaine,and deferiprone.In addition,8 hub genes were also identified:glycogen phosphorylase muscle associated(PYGM),glyceraldehyde-3-phosphate dehydrogenase spermatogenic(GAPDHS),enolase 3(ENO3),aldolase fructose-bisphosphate C(ALDOC),phosphoglucomutase 2(PGM2),enolase 2(ENO2),phosphoglycerate mutase 2(PGAM2),and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3(PFKFB3).Based on hub gene predictions,the miRNA-TF-Hub gene network revealed complex interactions between 163 miRNAs,77 TFs,and hub genes.The results of ROC showed that the except for GAPDHS,the area under curve(AUC)values of the other 7 hub genes were greater than 0.758,indicating their favorable diagnostic performance.CONCLUSION:PYGM,GAPDHS,ENO3,ALDOC,PGM2,ENO2,PGAM2,and PFKFB3 are hub genes in DR,and hypoxia-related hub genes exhibited favorable diagnostic performance.

Identification and Validation of Vascular-Associated Biomarkers for the Prognosis and Potential Pathogenesis of Hypertension Using Comprehensive Bioinformatics Methods

Background: Hypertension, also known as increased blood pressure, is a phenomenon in which blood flows in blood vessels and causes persistently higher-than-normal pressure on the vessel wall. The identification of novel prognostic and pathogenesis biomarkers plays a key role in the management of hypertension. Methods: The GSE7483 and GSE75815 datasets from the gene expression omnibus (GEO) database were used to identify the genes associated with hypertension that were differentially expressed genes (DEGs). The functional role of the DEGs was elucidated by gene body (GO) enrichment analysis. In addition, we performed an immune infiltration assay and GSEA on the DEGs of hypertensive patients and verified the expression of novel DEGs in the blood of hypertensive patients by RT-qPCR. Results: A total of 267 DEGs were identified from the GEO database. GO analysis revealed that these genes were associated mainly with biological processes such as fibroblast proliferation, cell structural organization, extracellular matrix organization, vasculature development regulation, and angiogenesis. We identified five possible biomarkers, Ecm1, Sparc, Sphk1, Thbsl, and Mecp2, which correlate with vascular development and angiogenesis characteristic of hypertension by bioinformatics, and explored the clinical expression levels of these genes by RT-qPCR, and found that Sparc, Sphk1, and Thbs1 showed significant up-regulation, in agreement with the results of the bioinformatics analysis. Conclusion: Our study suggested that Sparc, Sphk1 and Thbs1 may be potential novel biomarkers for the diagnosis, treatment and prognosis of hypertension and that they are involved in the regulation of vascular development and angiogenesis in hypertension.

Mining elite loci and candidate genes for root morphology-related traits at the seedling stage by genome-wide association studies in upland cotton(Gossypium hirsutum L.)

Root system architecture plays an essential role in water and nutrient acquisition in plants,and it is significantly involved in plant adaptations to various environmental stresses.In this study,a panel of 242 cotton accessions was collected to investigate six root morphological traits at the seedling stage,including main root length(MRL),root fresh weight(RFW),total root length(TRL),root surface area(RSA),root volume(RV),and root average diameter(AvgD).The correlation analysis of the six root morphological traits revealed strong positive correlations of TRL with RSA,as well as RV with RSA and AvgD,whereas a significant negative correlation was found between TRL and AvgD.Subsequently,a genome-wide association study(GWAS)was performed using the root phenotypic and genotypic data reported previously for the 242 accessions using 56,010 single nucleotide polymorphisms(SNPs)from the CottonSNP80K array.A total of 41 quantitative trait loci(QTLs)were identified,including nine for MRL,six for RFW,nine for TRL,12 for RSA,12 for RV and two for AvgD.Among them,eight QTLs were repeatedly detected in two or more traits.Integrating these results with a transcriptome analysis,we identified 17 candidate genes with high transcript values of transcripts per million(TPM)≥30 in the roots.Furthermore,we functionally verified the candidate gene GH_D05G2106,which encodes a WPP domain protein 2in root development.A virus-induced gene silencing(VIGS)assay showed that knocking down GH_D05G2106significantly inhibited root development in cotton,indicating its positive role in root system architecture formation.Collectively,these results provide a theoretical basis and candidate genes for future studies on cotton root developmental biology and root-related cotton breeding.

PbrARF4 contributes to calyx shedding of fruitlets in ‘Dangshan Suli’ pear by partly regulating the expression of abscission genes

Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (DAFB) higher levels of indoleacetic acid (IAA) and tryptophan (Trp) in calyx persistence fruitlet (CPF) than calyx shedding fruitlet (CSF) ofDanshan Suli’ pear (Pyrus bretschneideri Rhed.). Consisting with this, the activity of indolealdehyde oxidase (IAAIdO), which promotes IAA synthesis, was remarkably increased, and that of peroxidase(POD), which degrades IAA, dropped markedly in CPF but not in CSF. Further, qRT-PCR results revealed that most of 31 PbrARFs (encoding auxin response factors) in Pyrus bretschneideri were highly expressed in CPF, whereas PbrARF4, PbrARF24 and PbrARF26 were significantly downregulated in CPF vis-a-vis CSF. Phylogenetic analysis revealed that 6 PbrARFs clustered in the group III, where PbrARF4 showed the closest affinity with AtARF1 that promotes organ abscission, indicating a putative role of PbrARF4 in mediating the process of calyx shedding in pear. In fact, the ectopic overexpression of PbrARF4 in Solanum lycopersicum resulted in an earlier-formed and deeper abscission layer (AL) in the transgenic plants, whose calyxes were more prone to wilt at the mature red stage (MR) compared with the control plants (wild-type). More importantly, expression levels of the abscission genes SILS and Sl Cel2 in transgenic plants overexpressing PbrARF4 were significantly upregulated in comparation with the WT, whereas those of Sl BI and Sl TAPG2 were considerably inhibited. Further, PbrJOINTLESS and PbrIDA,the two genes related to calyx shedding in pear, were up-regulated more in CSF than CPF. The findings contribute to a better understanding of PbrARFs involved in fruitlet calyx shedding of pear, which could prove beneficial to improving the quality of pear fruit.

Regulatory potential of soil available carbon,nitrogen,and functional genes on N_(2)O emissions in two upland plantation systems

Dynamic nitrification and denitrification processes are affected by changes in soil redox conditions,and they play a vital role in regulating soil N_(2)O emissions in rice-based cultivation.It is imperative to understand the influences of different upland crop planting systems on soil N_(2)O emissions.In this study,we focused on two representative rotation systems in Central China:rapeseed–rice(RR)and wheat–rice(WR).We examined the biotic and abiotic processes underlying the impacts of these upland plantings on soil N_(2)O emissions.The results revealed that during the rapeseed-cultivated seasons in the RR rotation system,the average N_(2)O emissions were 1.24±0.20 and 0.81±0.11 kg N ha^(–1)for the first and second seasons,respectively.These values were comparable to the N_(2)O emissions observed during the first and second wheat-cultivated seasons in the WR rotation system(0.98±0.25 and 0.70±0.04 kg N ha^(–1),respectively).This suggests that upland cultivation has minimal impacts on soil N_(2)O emissions in the two rotation systems.Strong positive correlations were found between N_(2)O fluxes and soil ammonium(NH_(4)^(+)),nitrate(NO_(3)^(–)),microbial biomass nitrogen(MBN),and the ratio of soil dissolved organic carbon(DOC)to NO_(3)^(–)in both RR and WR rotation systems.Moreover,the presence of the AOA-amoA and nirK genes were positively associated with soil N_(2)O fluxes in the RR and WR systems,respectively.This implies that these genes may have different potential roles in facilitating microbial N_(2)O production in various upland plantation models.By using a structural equation model,we found that soil moisture,mineral N,MBN,and the AOA-amoA gene accounted for over 50%of the effects on N_(2)O emissions in the RR rotation system.In the WR rotation system,soil moisture,mineral N,MBN,and the AOA-amoA and nirK genes had a combined impact of over 70%on N_(2)O emissions.These findings demonstrate the interactive effects of functional genes and soil factors,including soil physical characteristics,available carbon and nitrogen,and their ratio,on soil N_(2)O emissions during upland cultivation seasons under rice-upland rotations.

Fate and Behavior of Tetracycline Resistance Genes in Activated Carbon Adsorption

The accessibility of tetracycline resistance gene (tetG) into the pores of activated carbon (AC), as well as the impact of the pore size distribution (PSD) of AC on the uptake capacity of tetG, were investigated using eight types of AC (four coal-based and four wood-based). AC showed the capability to admit tetG and the average reduction of tetG for coal-based and wood-based ACs at the AC dose of 1 g·L-1 was 3.12 log and 3.65 log, respectively. The uptake kinetic analysis showed that the uptake of the gene followed the pseudo-second-order kinetics reaction, and the uptake rate constant for the coal-based and wood-based ACs was in the range of 5.97 × 10-12 - 4.64 × 10-9 and 7.02 × 10-11 - 1.59 × 10-8 copies·mg-1·min-1, respectively. The uptake capacity analysis by fitting the obtained experiment data with the Freundlich isotherm model indicated that the uptake constant (KF) values were 1.71 × 103 - 8.00 × 109 (copies·g-1)1-1/n for coal-based ACs and 7.00 × 108 - 3.00 × 1010 (copies·g-1)1-1/n for wood-based ones. In addition, the correlation analysis between KF values and pore volume as well as pore surface at different pore size regions of ACs showed that relatively higher positive correlation was found for pores of 50 - 100 Å, suggesting ACs with more pores in this size region can uptake more tetG. The findings of this study are valuable as reference for optimizing the adsorption process regarding antibiotic resistance-related concerns in drinking water treatment.

The Application of Nicotiana benthamiana as a Transient Expression Host to Clone the Coding Sequences of Plant Genes

Coding sequences (CDS) are commonly used for transient gene expression, in yeast two-hybrid screening, to verify protein interactions and in prokaryotic gene expression studies. CDS are most commonly obtained using complementary DNA (cDNA) derived from messenger RNA (mRNA) extracted from plant tissues and generated by reverse transcription. However, some CDS are difficult to acquire through this process as they are expressed at extremely low levels or have specific spatial and/or temporal expression patterns in vivo. These challenges require the development of alternative CDS cloning technologies. In this study, we found that the genomic intron-containing gene coding sequences (gDNA) from Arabidopsis thaliana, Oryza sativa, Brassica napus, and Glycine max can be correctly transcribed and spliced into mRNA in Nicotiana benthamiana. In contrast, gDNAs from Triticum aestivum and Sorghum bicolor did not function correctly. In transient expression experiments, the target DNA sequence is driven by a constitutive promoter. Theoretically, a sufficient amount of mRNA can be extracted from the N. benthamiana leaves, making it conducive to the cloning of CDS target genes. Our data demonstrate that N. benthamiana can be used as an effective host for the cloning CDS of plant genes.

Dissemination of Resistance Integrons and Genes Coding for Blse and Cabapenemases in the Urban Drainage Network in Cote d’Ivoire

Antibiotic resistance has become a major threat to human health worldwide. Environment, particularly the water environment, has long been overlooked as a player in the antibiotic resistance cycle, although its role remains unclear. These can provide an ideal setting for the acquisition and dissemination of antibiotic resistance, as they are frequently affected by anthropogenic activities. The objective of this study was to establish a diffusion map of resistance integrons used as genetic markers of resistance associated with antibiotic resistance conferring genes (ARGs). Total DNA extracts from non-cultivable bacterial communities were used for the analyses. These communities were obtained from wastewater samples from 14 sites upstream and downstream of drainage channels or effluents in the cities of Abidjan, Bouaké, and Yamoussoukro. The results obtained correspond to the number of positives among the treated samples (n = 39). Among the genetic markers of dissemination, class 1 integrons were the most evident in 94.8% of samples in Abidjan (93.3%), Bouaké (100%) and Yamoussoukro (91.6%). Class 2 integrons and class 3 integrons were found respectively in 41% and 51% of all samples. Genes coding for β-lactamases and blaTEM was identified in almost all samples at a rate of 97.4%. A co-presence of the three genes blaTEM, blaSHV and blaCTX-M is also remarkable in the sites of the city of Yamoussoukro. Among the genes coding for carbapenemases, only blaKPC 17.94%, blaNDM 30.76% and blaOXA48 38.46% were detected in the samples.