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1.
Braz. j. microbiol ; 47(4): 793-799, Oct.-Dec. 2016. tab
Article in English | LILACS | ID: biblio-828190

ABSTRACT

Abstract Triazole fungicides are used broadly for the control of infectious diseases of both humans and plants. The surge in resistance to triazoles among pathogenic populations is an emergent issue both in agriculture and medicine. The non-rational use of fungicides with site-specific modes of action, such as the triazoles, may increase the risk of antifungal resistance development. In the medical field, the surge of resistant fungal isolates has been related to the intensive and recurrent therapeutic use of a limited number of triazoles for the treatment and prophylaxis of many mycoses. Similarities in the mode of action of triazole fungicides used in these two fields may lead to cross-resistance, thus expanding the spectrum of resistance to multiple fungicides and contributing to the perpetuation of resistant strains in the environment. The emergence of fungicide-resistant isolates of human pathogens has been related to the exposure to fungicides used in agroecosystems. Examples include species of cosmopolitan occurrence, such as Fusarium and Aspergillus, which cause diseases in both plants and humans. This review summarizes the information about the most important triazole fungicides that are largely used in human clinical therapy and agriculture. We aim to discuss the issues related to fungicide resistance and the recommended strategies for preventing the emergence of triazole-resistant fungal populations capable of spreading across environments.


Subject(s)
Humans , Triazoles/poisoning , Ecosystem , Drug Resistance, Fungal , Agriculture , Fungi/drug effects , Antifungal Agents/pharmacology , Plant Diseases/microbiology , Triazoles/therapeutic use , Fungi/physiology , Fungicides, Industrial , Mycoses/microbiology , Mycoses/drug therapy , Antifungal Agents/therapeutic use
2.
Ciênc. rural ; 41(3): 369-372, mar. 2011. ilus
Article in English | LILACS-Express | LILACS | ID: lil-579651

ABSTRACT

In the harvest year of 2004, a random sample of seed lots (n=165) from six rice-growing regions of Rio Grande do Sul (RS) State, Brazil, were examined under seed health blotter test. Fungi growth resembling Bipolaris or Drechslera spp. was isolated and identified at the species level. Observations on the anamorphic structures (conidiophores and conidia) allowed separation of isolates into three groups. Pseudothecia, asci and ascospores from sexual crosses between isolates from a same anamorphic group but originated from different regions showed the typical characteristics of three recognized species (anamorph/teleomorph): Bipolaris cynodontis (Cochliobolus cynodontis); B. curvispora (C. melinidis) and B. oryzae (C. miyabeanus). All species were widely distributed across the rice-growing regions. Overall, the most prevalent species were B. oryzae (44.6 percent) and B. curvispora (42,9 percent) followed by B. cynodontis (24,1 percent). This is the first report of B. cynodontis associated with rice seeds in Brazil and the preliminary identification of B. curvispora in rice by the observation of the teleomorph phase was confirmed. The regional occurrence of a complex of pathogenic Bipolaris species related to brown spot epidemics in other countries, may have epidemiological consequences in the region which deserve further investigation.


Uma amostra aleatória (n=165) de lotes de sementes de seis regiões produtoras de arroz no Estado do Rio Grande do Sul (RS), Brasil, ano de colheita 2004, foi examinada em teste blotter de sanidade de sementes. Fungos semelhantes a espécies de Bipolaris e Drechslera foram isolados para identificação das espécies. A observação de estruturas da fase anamórfica (conidióforos e conídios) permitiu separar os isolados em três grupos. Cruzamentos sexuais induzidos em isolados do mesmo grupo, mas originados de diferentes regiões, resultaram em pseudotécio, ascos e ascósporos, permitindo a identificação de três espécies (anamorfo/teleomorfo): Bipolaris cynodontis (Cochliobolus cynodontis); B. curvispora (C. melinidis) e B. oryzae (C. miyabeanus). Todas as espécies estavam distribuídas nas seis regiões produtoras no Rio Grande do Sul. Em geral, a espécie mais prevalente nas amostras foi B. oryzae (44,6 por cento) e B. curvispora (42,9 por cento) seguido de B. cynodontis (24,1 por cento). Este é o primeiro relato de B. cynodontis associada a sementes de arroz no Brasil, e confirma-se a ocorrência de B. curvispora pela observação da fase teleomórfica. A ocorrência de um complexo de espécies patogênicas de Bipolaris, relacionadas com a mancha parda em outros países, pode ter consequências epidemiológicas na região, o que merece futura atenção.

3.
Ciênc. rural ; 40(3): 661-665, mar. 2010. tab, ilus
Article in Portuguese | LILACS-Express | LILACS | ID: lil-542979

ABSTRACT

A podridão "olho de boi", causada pelo fungo Cryptosporiopsis perennans, é uma das doenças de pós-colheita da macieira mais importantes no Brasil. Os objetivos deste trabalho foram desenvolver e avaliar um meio semiseletivo para a recuperação e mensuração da população epífita de C. perennans em maçãs "Fuji". A suplementação de BDA com tetraciclina, nistatina e iprodiona, nas respectivas concentrações de 12,5; 1 e 1µg p.a mL-1, proporcionou o desenvolvimento de colônias de C. perennans estatisticamente igual (P>0,05) ao observado no meio BDA. Em condições de infecção natural e em amostras pré-inoculadas com C. perennans, o meio semiseletivo permitiu detectar e quantificar a população do fungo na superfície dos frutos, além de ter inibido o crescimento de fungos leveduriformes, dematiáceos e leveduras. Em lavagens de frutos previamente inoculados, o número de conídios recuperados com o meio semiseletivo apresentou correlação (r=0,88; P<0,05) com a concentração do inóculo aspergido sobre os frutos.


Bull's eye rot, caused by Cryptosporiopsis perennans, is one of the most important apple's posharvest diseases in Brazil. The aim of this research was to develop and evaluate a semi-selective media to recovery and quantification of the epiphytic population of C. perennans on the apple fruit surface. A PDA medium amended with tetracycline, nistatine and iprodione in concentrations of 12.5; 1 and 1µg i.a.mL-1, respectively, allowed the development of C. perennans colonies statistically similar (P>0.05) to those in PDA media. Nistatine concentrations higher than 1µg.mL-1 inhibited the growth of the pathogen. Under natural infection conditions and pre-inoculation with C. perennans, the media allowed the detection and quantification of the fungal population on the fruit surface without affecting C. perennans development. Number of conidia observed in pre-inoculated fruits was correlated (r=0.88; P<0.05) to inoculum concentration sprayed on the fruit surface.

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