resistance

摘要： Multi-drug resistance (MDR) in Enterobacteriaceae poses critical public health threat in Nigeria and the global world. This resistant mechanism might be plasmid mediated or chromosomal. Escherichia coli are Gram negative pathogen with a global distribution rate. The study was carried out to determine MDR and plasmid profiling of E. coli isolates from urine, feaces and poultry litter. The samples were cultured on eosine methylene blue agar and incubated for 24 hours at 37°C. Results obtained showed a percentage prevalence of 30% for the urine samples which were the most prevalent, while the prevalence of E. coli from the feacal and poultry litter was 8% and 28% respectively. Identified E. coli were screened for antibiotic susceptibility by Kirby Bauer diffusion method. The results on susceptibility of E. coli to tested antibiotics before plasmid curing showed 100% resistance to cefuroxime and augumentin, while 75% resistance was observed in gentamicine, ciprofloxacin and ofloxacine. Cefixime and cefdazidime resistance were 62.5% on E. coli and the least resistance was observed in nitrofurantion (25%). The poultry litter and urine isolates recorded lower resistance level to antibiotics, compared to the feacal isolates. After plasmid curing the percentage of resistance reduced. The only antibiotics that responded positively was nitrofurantion, with high sensitivity of 87% for feacal isolate, 100% for urine isolates, and 78% for poultry litter isolates after plasmid curing. Twenty (20) of the thirty seven (37) isolates were still resistant to more than two antibiotics after the plasmid curing. Of the twenty isolates, 18 (90%) were found to harbor single plasmid, while 2 (10%) did not possess plasmid. This study concludes that nitrofurantion was the most effective antibiotics on Escherichia coli and plasmids were responsible partly for resistance.

摘要： Information on Culex mosquitoes (vectors of filarial worm and viral encephalitis) from northern Nigeria is scanty, hindering evidence-based control. Here, two Culex populations (Kano and Kaduna) were characterized. Culex quinquefasciatus and Culex pipiens were found breeding in sympatry, with some hybrid individuals identified. Larval bioassays revealed high temephos resistance (LC50s = 1.34 mg/mL and 3.01 mg/mL for Kano and Kaduna, respectively). Larvae were more sensitive to α-cypermethrin (LC50s = 0.026 mg/mL and 0.067 mg/mL for Kano and Kaduna). WHO adult tube bioassays revealed high pyrethroid and DDT resistance, with mortalities of 44.01% ± 6.79%, 35.83% ± 12.58%, 29.69% ± 9.97% and 52.47% ± 4.34% for permethrin, deltamethrin, α-cypermethrin and DDT, respectively. Highest resistance was observed with bendiocarb (mortality = 13.58% ± 3.98%). High resistance was obtained with fenitrothion and malathion (mortalities = 21% ± 4.76% and 56.47% ± 8.67%, respectively), while a full susceptibility was observed with pirimiphos-methyl. Pre-exposure to piperonylbutoxide (PBO) significantly recovered α-cypermethrin susceptibility (mortality = 82% ± 5.16%, χ2 = 50.99, p kdr genotype and resistance phenotype. Sequencing of fragments of the acetylcholinesterase-1 gene detected no G119S mutation, in malathion-alive and malathion-dead females. These suggest a preeminent role of metabolic resistance in these Culex populations.

摘要： A number of plant pathogenic species of Phytophthora are known to produce different classes of secretory proteins during interactions with their hosts.Although several small cysteine-rich(SCR)secretory proteins,conserved in oomycete pathogens,have been identified in Phytophthora,their specific involvement in these interactions remains unknown.In this study,an SCR effector encoded by Pn SCR82 in P.nicotianae was identified and shown to have similarities to P.cactorum phytotoxic protein,Pc F(Phytophthora cactorum Fragaria).Agroinfection with potato virus X vector,Pn SCR82,was capable of inducing plant hypersensitive cell death in Nicotiana benthamiana and Solanum lycopersicum.Real-time PCR results indicated that transiently expressed Pn SCR82 in N.benthamiana leaves activated the jasmonate,salicylic acid and ethylene signaling pathways.Transient expression of Pn SCR82 enhanced plant resisitance to P.capsici.In summary,our results demonstrated that P.nicotianae Pn SCR82 elicits defensive responses in N.benthamiana and may potentially play a significant role in future crop protection programs.

摘要： Cancer stem cells(CSCs)possess self-renewal and differentiation potential,which may be related to recurrence,metastasis,and radiochemotherapy resistance during tumor treatment.Understanding the mechanisms via which CSCs maintain self-renewal may reveal new therapeutic targets for attenuating CSC resistance and extending patient life-span.Recent studies have shown that amino acid metabolism plays an important role in maintaining the self-renewal of CSCs and is involved in regulating their tumorigenicity characteristics.This review summarizes the relationship between CSCs and amino acid metabolism,and discusses the possible mechanisms by which amino acid metabolism regulates CSC characteristics particularly self-renewal,survival and stemness.The ultimate goal is to identify new targets and research directions for elimination of CSCs.

摘要： Vegetation uprooting is a complex process which depends on many interrelated factors.In this paper,attention is focused on the flow-induced uprooting in river bends,where the flow characteristics vary as effected by the channel's curvature and its continuous changing in the downstream direction.Results are presented by an experimental work done in a high-amplitude meandering flume with mature herbaceous vegetation on the bed.In the first part of the paper,the variation along the bend of the geometrical(length,thickness,and radical architecture)and the mechanical(resistance force)characteristics of the roots are analyzed.In the second part of the paper,the transition from the condition of vegetation distributed on the bed to the condition of vegetation uprooted by the flow is experimentally examined.The results show that the flow-induced uprooting varies along the bend depending on the roots'geometrical and mechanical characteristics which are,in turn,influenced by the variation of the water surface elevation along the bend itself.It has been found that lower values of the resistance force occur at the apex section where the roots are characterized by higher values of length and lower values of thickness and have radical apparatuses characterized by limited encumbrance,a high number of roots,and low bushyness.The flow-induced uprooting especially develops close to the outer bank along the channel reach between the bend entrance and the apex section,where the root resistance force and the water surface slope tend to decrease in value.

摘要： BACKGROUND Several strategies have been implemented to reduce or abolish the life-threatening risk of endoscopic retrograde cholangiopancreatography(ERCP)-related multidrug-resistant infections due to duodenoscopes contaminations;among those strategies,serial microbiologic tests,thorough reprocessing schedules,and use of removable scope cap have been adopted,but the potential cross-infection risk was not eliminated.AIM To review available evidence in the field of single-use duodenoscopes(SUD)use for ERCP.METHODS An overview on ongoing clinical studies was also performed to delineate which data will become available in the next future.RESULTS One bench comparative study and four clinical trials performed with EXALT model-D(Boston Scientific Corp.,United States)have been identified.Of them,one is a randomized controlled trial,while the other three studies are prospective single-arm,cross-over studies.Pooled technical success rate(4 studies,368 patients)was 92.9%[95%confidence interval(CI):89.9-95.5;I2:11.8%].Pooled serious adverse event(4 studies,381 patients)rate was 5.9%[3.7%-8.5%;I2:0.0%].CONCLUSION Although few clinical trials are available,evidence is concordant in identifying an absolute feasibility and safety and feasibility for SUD use for ERCP.The expertise and quality of evidence in this field are going to be improved by further large clinical trials;data on cost-effectiveness and environmental impact will be needed for a worldwide spread of SUD use for ERCP.

摘要： Cell death is an important physiological phenomenon in life.It can be programmed or unprogrammed.Unprogrammed cell death is usually induced by abiotic or biotic stress.Recent studies have shown that many proteins regulate both cell death and immunity in plants.Here,we provide a review on the advances in plant immunity with cell death,especially the molecular regulation and underlying mechanisms of those proteins involved in both cell death and plant immunity.In addition,we discuss potential approaches toward improving plant immunity without compromising plant growth.

摘要： Common bean(Phaseolus vulgaris) is an annual legume crop that is grown worldwide for its edible dry seeds and tender pods. Marsh spot(MS) of the seeds is a physio-genic stress disease affecting seed quality in beans. Studies have suggested that this disease involves a nutritional disorder caused by manganese deficiency, but the inheritance of resistance to this disease has not been reported. A biparental genetic population composed of 138 recombinant inbred lines(RILs) was developed from a cross between an MS resistant cultivar ‘Cran09’ and an MS susceptible cultivar ‘Messina’. The 138 RILs and their two parents were evaluated for MS resistance during five consecutive years from 2015 to 2019 in sandy and heavy clay soils in Morden, Manitoba, Canada. The MS incidence(MSI) and the MS resistance index(MSRI) representing disease severity were shown to be both highly correlated heritable traits that had high broad-sense heritability values(H;) of 86.5% and 83.2%, respectively. No significant differences for MSI and MSRI were observed between the two soil types in all five-(MSI) or four-year(MSRI) data collection, but significant correlations among years were observed despite MS resistance was moderately affected by year. The MSIs and MSRIs displayed a right-skewed distribution, indicating a mixed genetic model involving a few major genes and polygenes. Using the joint segregation analysis method, the same four major genes with additive-epistasis effects showed the best fit for both traits, explaining 84.4% and85.3% of the phenotypic variance for MSI and MSRI, respectively. For both traits, the M1, M2, M3 and m4 acted as the favorable(resistant) alleles for the four genes where M and m represent two alleles of each gene. However, due to epistatic effects, only the individuals of the M1 M2 M3 M4 haplotype appeared to be highly resistant, whereas those of the m1 m2 m3 M4 haplotype were the most susceptible. The m4 allele significantly suppressed the additive effects of M1 M2 M3 on resistance, but decreased susceptibility due to the additive effects of m1 m2 m3. Further quantitative trait locus(QTL) mapping is warranted to identify and validate individual genes and develop molecular markers for marker-assisted selection of resistant cultivars.

摘要： Melanoma is a relentless type of skin cancer which involves myriad signaling pathways which regulate many cellular processes.This makes melanoma difficult to treat,especially when identified late.At present,therapeutics include chemotherapy,surgical resection,biochemotherapy,immunotherapy,photodynamic and targeted approaches.These interventions are usually administered as either a single-drug or in combination,based on tumor location,stage,and patients'overall health condition.However,treatment efficacy generally decreases as patients develop treatment resistance.Genetic profiling of melanocytes and the discovery of novel molecular factors involved in the pathogenesis of melanoma have helped to identify new therapeutic targets.In this literature review,we examine several newly approved therapies,and briefly describe several therapies being assessed for melanoma.The goal is to provide a comprehensive overview of recent developments and to consider future directions in the field of melanoma.

摘要： In this paper,the basic characteristics of Quanyou series of high-quality rice varieties,suitable for planting in Hubei ecological areas(except Wuling Mountain Area)and approved by the provincial government in 2020,were analyzed.The result showed that,there were 12 suitable rice varieties.From the perspective of the main body of variety breeding,the varieties were mainly selected by enterprises;Quanyou series of high-quality hybrid combinations generally had large grains per panicle and high seed setting rate,but the effective panicle number was general,and the yield per panicle contributed more in unit yield.Quanyou series of high-quality hybrid combinations can be used for the selection and breeding of varieties with good rice quality and blast resistance,but breeding varieties resistant to bacterial blight and brown planthopper should be strengthened.

摘要： AbstractThis paer uses a new method to deal with skin effect problem of tubular bus. Thenumericalformulars for calculating altemating current resistamce are deduced By means of one-dimensionSearch methodit detemnines critical thickness referred tominimum alternating current resistance ofthe bus. The satisfactory calculated results also given in the paper.