Banca de QUALIFICAÇÃO: FELIPE EMMANUEL DO ESPÍRITO SANTO GOMES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : FELIPE EMMANUEL DO ESPÍRITO SANTO GOMES
DATA : 06/12/2016
HORA: 10:00
LOCAL: Sala SS1 - Depto. de Biologia Celular e Genética - CB/UFRN
TÍTULO:

STUDY OF GROUP I INTRON VARIABILITY IN THE MITOCHONDRIAL 23S GENE OF PATOGENIC FUNGI OF THE GENUS CRYPTOCOCCUS AND ITS RELATIONSHIP TO SUSCEPTIBILITY TO ANTIFUNGAL

PALAVRAS-CHAVES:

Cryptococcosis, PCR-RFLP, genotyping, Group I intron, antifungal susceptibility.

PÁGINAS: 86
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Cryptococcosis, caused by the fungal species Cryptococcus neoformans or Cryptococcus gattii, is one of the most important systemic and/or opportunistic diseases in the world and its treatment depends on the correct identification of its species and genotypes. The success of the treatment and the prognosis of the patients depend on a species/genotype-specific diagnosis of the causative agent, usually done by PCR-RFLP of the URA5 gene. Each species has four genotypes, which present differences in their ecology, epidemiology, geographical distribution and antifungal susceptibility. The search for more direct molecular markers without the need for digestion or sequencing is attractive for rapid recognition of genotypes or relevant characteristics such as virulence and antifungal susceptibility. In this way, group I autocatalytic introns in the mitochondrial LSU rRNA were evaluated as potential molecular marker for the genotypes of C. neoformans and C. gattii. Seventy-Seven Brazilian isolates were used, most of the genotype VNI (39 strains) followed by 20 VGII, 5 VNIV, 4 VNII, 3 VNIII, 2 VGI, 2 VGIII and 2 VGIV. The introns Cne.mL2449 and Cne.mL2504 were amplified in a single PCR with complementary primers to the flanking region of the introns LSU rRNA gene. PCR products showed a significant polymorphism between C. neoformans and C. gattii genotypes. Some strains had none, one, two or all three introns followed. Sequencing of the PCR products indicated the presence of a new intron, named Cne.mL2439 in C. neoformans and Cga.mL2439 in C. gattii, belonging to subclass IB2, in the LSU rRNA gene, not previously described in the mitochondrial genome of Cryptococcus.  Interestingly, non-intron genotypes are those known to be more virulent and less susceptible to antifungal agents. In antifungal susceptibility assays, we also observed higher MICs for the non-intron isolates for amphotericin B, itraconazole and 5-flucytosine. These findings suggest that these elements can be used as potential molecular markers for genotyping, virulence and/or antifungal resistance. Finally, phylogenetic analyzes suggested high sequence similarity between the introns Cne.mL2449, Cne.mL2504 and Cne.mL2439/Cga.mL2439 with other mitochondrial introns present in the genes COX1, COX2, COX3, NAD5, ATP9, COB, LSU of fungi supporting the hypothesis of horizontal transfer of these elements.

MEMBROS DA BANCA:
Presidente - 1251018 - RIVA DE PAULA OLIVEIRA
Interno - 1507794 - RODRIGO JULIANI SIQUEIRA DALMOLIN
Externo ao Programa - 1804884 - VIVIAN NOGUEIRA SILBIGER