RESUMO
OBJECTIVE: Multilocus sequence typing is a powerful method for genotyping of clinical isolates of Candidaalbicans. Cross-contamination between the patients is an important reason for nosocomial infections. Oropharyngeal candidiasis (OPC) caused by C. albicans is an important problem in patients with head and neck cancer, in Cancer Institute of Tehran. Here we studied the endemic genotypes of C. albicans isolates and the relationship between geographic distributions, potential cross-contaminations and the expression of SAP2 gene, an important gene in oral candidiasis, with MLST groups. MATERIAL AND METHODS: A total of 32 clinical strains of C. albicans isolated from head and neck cancer patients with oropharyngeal candidiasis were subjected to MLST analysis and SAP2 gene expression was analyzed by Real-time PCR. RESULTS: We identified 75 polymorphic sites in 7 loci of C. albicans isolates and 30 diploid sequence types which 27 of them were found as new. After eBURST analysis, our results determined that CC 124 was the most prevalent group among all CCs. SAP2 gene showed high expression in almost all OPC patients' isolates, compared to the control. CONCLUSION: We found few genetically-related as well as identical isolates among the 32 Candida strains which indicated low cross-contaminations among the patients. There was no relationship between C. albicans MLST profiles and their geographic distribution, cancer type and SAP2 gene expression. This lack of correlation was possibly due to the small understudy population; hence, finding more relevance requires studies with a higher number of samples.
Assuntos
Ácido Aspártico Endopeptidases/genética , Candida albicans/genética , Candidíase Bucal/epidemiologia , Candidíase Bucal/microbiologia , Proteínas Fúngicas/genética , Genótipo , Neoplasias de Cabeça e Pescoço/microbiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Candida albicans/classificação , DNA Fúngico/genética , Feminino , Expressão Gênica , Técnicas de Genotipagem , Neoplasias de Cabeça e Pescoço/complicações , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Técnicas de Tipagem Micológica , Filogenia , Adulto JovemRESUMO
We report the observation of field emission (FE) from InP nanocrystals (NCs) epitaxially grown on an array of p-Si nanotips. We prove that FE can be enhanced by covering the InP NCs with graphene. The measurements are performed inside a scanning electron microscope chamber with a nano-controlled W-thread used as an anode. We analyze the FE by Fowler-Nordheim theory and find that the field enhancement factor increases monotonically with the spacing between the anode and the cathode. We also show that InP/p-Si junction has a rectifying behavior, while graphene on InP creates an ohmic contact. Understanding the fundamentals of such nanojunctions is key for applications in nanoelectronics.
