Cellular immobilization represents an alternativefor the bioprocess conduction, in which the cells are kept in a matrix and can be used over long periods. The objective of this work was to test a new fungi immobilization methodology with reduced cost to evaluate the viability of these fungi when submitted to the new encapsulation method, and to determine the ideal temperature to store the immobilized fungi. The mycelium of the fungi Aspergillus niger, Cladosporium cladosporioides and Penicillium solitum were mixed with 15 g of titrated rice and 3 g of sodium alginate, which was dripped in a 0.25 M calcium chloride solution for the formation of pellets. After drying in an oven at 26ºC, the granules were stored at three temperatures: room, refrigerator and freezer. The platings were carried out every 15 days in culture medium. The evaluations of the colony size and sporulation were carried out 7, 14 and 12 days after plating, for 195 days for A. niger, 225 days for C. cladosporioides, and 210 days for P. solitum. Storage temperature did not affect the mycelial development of A. niger and P. solitum. However, sporulation was reduced for the granules stored in the freezer. The mycelial development of C. cladosporioides was influenced by temperature. The granules conserved at room temperature had lower viability than those stored in the refrigerator and freezer. In the Scanning Electronic Microscopy analysis, it was observed that the immobilization is a safe method in which the fungus mycelium remains inside the granule, facilitating transport, storage and application of micro-organisms. KEYWORDS: cellular immobilization; encapsulation of fungi; sodium alginate; granulated formulation. RESUMO:A imobilização celular representa uma alternativa para a condução de bioprocessos. As células ficam retidas em matrizes e podem ser utilizadas por longos períodos. O objetivo deste trabalho foi testar uma nova metodologia de imobilização de fungos com custo reduzido, avaliar a viabilidade e segurança dos fungos submetidos ao novo método de encapsulamento e determinar a temperatura ideal para armazenar os fungos imobilizados. Os micé-lios dos fungos Aspergillus niger, Cladosporium cladosporioides e Penicillium solitum foram misturados com 15 g de arroz triturado e 3 g de alginato de sódio, que gotejava em uma solução de cloreto de cálcio a 0,25 M para a formação dos grânulos. Após a secagem em estufa a 26ºC, os grânulos foram armazenados em temperaturas ambiente, geladeira e freezer. Os plaqueamentos foram realizados a cada 15 dias em meio de cultura. As avaliações do tamanho das colônias e esporulação foram realizadas 7, 14 e 21 dias após o plaqueamento, durante 195 dias para A. niger, 225 dias para C. cladosporioides e 210 dias para P. solitum. A temperatura de armazenamento não afetou o desenvolvimento micelial de A. niger e P. solitum. Porém, a esporulação foi reduzida para os grânulos armazenados no freezer. O desenvolvimento micelial de C. cladosporioides foi influenciado pela temperatura. Os grânulos conservados ...
Black pepper (Piper nigrum L.) is a popular spice native of India, and Brazil is one of its most important producing countries. The main disease of black pepper in Brazil is fusariosis, caused by Fusarium solani f. sp. piperis. Symptoms include leaf chlorosis and defoliation, blight of stems or stem cuttings, and root and foot decay. During surveys conducted in the south of the state of Bahia, municipalities of Taperoá (13°34'S, 39°10'W) and Valencia (13°20'S, 39°14'W), stems of diseased plants covered with red or salmon-colored perithecia were observed, while twigs showed leaf chlorosis, leading to early death of the plants. Ascomata were solitary or in groups, mostly superficial or surrounded by mycelia, globose, subglobose, ovoid, and 122 to 400 μm diameter. Microscopic examination revealed unitunicate, cylindric asci, 60 to 90 × 8.5 to 16 μm, thin-walled, containing eight ascospores arranged obliquely in two rows. Ascospores are hyaline, elliptical to oblong, one-septate, constricted at the central septum, 10 to 16 × 4 to 6.5 μm (means ± S.D.: 13.1 ± 1.4 × 5.1 ± 0.6 μm), length/width (L/W) 1.9 to 3.7. Single-spored cultures were transferred to SNA medium (incubated at 20°C for 7 days with 12-h photoperiod) and on potato dextrose agar (25°C in dark) for characterization. The anamorph is characterized by the presence of chlamydospores, canoe-shaped sporodochial macroconidia with three to four septae, and microconidia formed on long monophialidic conidiophores. Based on morphological markers, isolates were identified as F. solani. The partial fragment of the TEF-1α gene of single-spored isolates (CML 2186, 2187, 2188, 2189, 2190, and 2191) were sequenced. BLAST analysis of the sequence resulted in 94 to 99% identity with a reference strain of F. solani f. sp. piperis (NRRL 22570, CML 1888). For pathogenicity tests, cv. Bragantina was used and two isolates were inoculated as 5-mm diameter mycelial plugs on the stem of four plants each. Four control plants were treated only with sterile culture medium. Plants were maintained in the greenhouse at 25°C and 75 to 85% relative humidity under 70% shade. All inoculated plants showed initial symptoms of stem necrosis in inoculated branches 7 days after inoculation. Symptoms were not observed on stems of control plants. Isolates were successfully reisolated and identified as F. solani f. sp. piperis, fulfilling Koch's postulates. Representative isolates were deposited at the Coleção Micológica de Lavras (CML) at Universidade Federal de Lavras, Brazil. Production of perithecia of the pathogen has been previously reported only in Pará and Espírito Santo States (1,3). It is not yet confirmed if this taxon is homothallic or heterothallic. To our knowledge, this is the first report of the associated teleomorph of F. solani f. sp. piperis infecting and causing black pepper fusariosis in Bahia, Brazil. The results suggest that the spread of ascospores from perithecia is likely to be one of the main inoculum sources of the disease on adjacent vines. There is evidence that this special form of F. solani actually represents a distinct species pathogenic to black pepper (2). References: (1) F. C. Albuquerque and S. Ferraz. Experientiae 22:133, 1976. (2) K. O'Donnell. Mycologia 92:919, 2000. (3) J. A. Ventura et al. Fitopatol. Bras. 11:361, 1986.
RESUMO: O objetivo deste trabalho foi avaliar o efeito do contato direto e da fração volátildo óleo de café verde, testado nas concentrações de 500, 1.000, 1.500 e 2.000 µL L-1, sobre o crescimento micelial e a esporulação dos fungos Penicillium roqueforti e Rhizopus stolonifer. O óleo essencial de cravo-da-índia na concentração de 800 µL L-1 foi utilizado para comparação. Nas concentrações de 1.500 e 2.000 µL L-1, o óleo de café verde em contato direto proporcionou redução da esporulação do fungo R. stolonifer , sendo estatisticamente semelhante ao óleo de cravo-da-índia. Na fração volátil do óleo de café verde, observou-se redução significativa da esporulação de P. roqueforti e R. stolonifer na concentração de 2.000 µL L-1. O óleo de café verde, em contato direto ou por volatilização, reduziu significativamente o crescimento micelial e a esporulação de ambos os fungos em comparação com a testemunha.
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