Transcriptional profiling of genes involved in n-hexadecane compounds assimilation in the hydrocarbon degrading Dietzia cinnamea P4 strain

The petroleum-derived degrading Dietzia cinnamea strain P4 recently had its genome sequenced and annotated. This allowed employing the data on genes that are involved in the degradation of n-alkanes. To examine the physiological behavior of strain P4 in the presence of n-alkanes, the strain was grown under varying conditions of pH and temperature. D. cinnamea P4 was able to grow at pH 7.0-9.0 and at temperatures ranging from 35 ºC to 45 ºC. Experiments of gene expression by real-time quantitative RT-PCR throughout the complete growth cycle clearly indicated the induction of the regulatory gene alkU (TetR family) during early growth. During the logarithmic phase, a large increase in transcriptional levels of a lipid transporter gene was noted. Also, the expression of a gene that encodes the protein fused rubredoxin-alkane monooxygenase was enhanced. Both genes are probably under the influence of the AlkU regulator.

Microbial counts of dark red latosol samples stored at different temperatures

The number of colony forming units (CFU) of different groups of bacteria and fungi in samples stored at temperatures of 5 to -12§C for 0-32 weeks was evaluated. The number of CFU obtained after the different periods of storage of red latossol soil was compared with the number of colonies obtained immediately after removal of soil samples (time zero). The number of total bacteria and actinomycetes in the samples remained pratically unchanged throughout the storage period. The number of Gram-negative bacteria decreased by as much as 69 per cent compared to control, while the number of Bacillus spp and of fungi increased 1.9 to 4.9 times starting from the 12th week in sample stored at 5§C. Except for the variations observed in fungal counts, the remaining groups of bacteria pratically showed the same variation in number of colonies in soil samples stored at 5§C and -12§.

Occurrence of hyphomycetes and actinomycetes in red-yellow latosol from a cerrado region in Brazil

Em área de cerrado, no município de Corumbataí, SP, foi realizado um estudo para quantificar as populaçöes de fungos filamentosos e de actinomicetos, em diferentes profundidades de latossolo vermelho amarelo, textura média, correlacionando-se com a umidade, matéria orgânica, pH do solo e com os fatores climáticos. A técnica utilizada foi a diluiçäo em série de amostras de solos compostas (n=4), utilizando-se o meio Martin com estreptomicina para fungos filamentosos e o meio de amido, para actinomicetos. Os fungos filamentosos foram mais abundantes na primeira camada do solo, 0-5cm, em relaçäo as demais profundidades. Houve variaçöes bimestrais dos números de fungos filamentosos e de actinomicetos. Um decréscimo acentuado de fungos foi verificado no mês de maio/88 em todas as profundidades do solo, quando houve menor temperatura do ar anual e alto índice pluviométrico mensal, atípico para este período no cerrado. Correlaçöes estatisticamente significativas e diretamente proporcionais foram obtidas entre o número de actinomicetos e o índice pluviométrico nas profundidades, 0-5cm e 50-100cm de profundidade, evidenciaram a importância da primeira camada de 0-5cm, devido a grande concentraçäo de microrganismos, principalmente dos fungos filamentosos, juntamente com os maiores teores de matéria orgânica

Interaction in culture medium of actinomycetes and native fungi with rhizobia that form nodules in Neonotonia wightii lackley (Perennial soybean)

Foram feitos estudos, em meio de cultura, de relaçöes entre fungos e actinomicetos do solo com rizóbios eficientes na nodulaçäo de Neonotonia wightii (soja-perene), com o objetivo de obter material a ser utilizado em inoculaçöes mistas desta leguminosa. Para este fim, foi instalado um ensaio de campo para coletas de amostras de solo e isolamento de microrganismos pertencentes a estes grupos, com capacidade de promover interfência no desenvolvimento de duas estirpes selecionadas de rizóbio. Os resultados indicam que as estirpes de Bradyhizobium sp utilizadas e eficientes na nodulaçäo de Neonotonia wightii apresentam grande sensibilidade, em meio de cultura, a substâncias produzidas nesses meios por actinomicetos e fungos

Repeated isolation of Dermatophilus-like organism from leprosy material.

An organism having actinomycetoid type of colonies has been grown repeatedly in pure culture from leprosy material using a solid medium. The isolates obtained from different biopsies, skin scrapes and mouse foot-pad harvests were found to be similar to each other in the routine taxonomical tests and had many characters common with Dermotophilus congolensis. Similar growth could be obtained from a strain of M. leprae from armadillo and also from a DOPA-positive mycobacterium isolated previously from the blood of a leprosy patient.