			Home About us Contact

Streptomyces Species (streptomyces + species)

Distribution by Scientific Domains

Life Sciences	85%

Selected Abstracts

Phylogenetic analysis of actinobacterial populations associated with Antarctic Dry Valley mineral soils

ENVIRONMENTAL MICROBIOLOGY, Issue 3 2009
Olubukola O. Babalola
Summary Despite the apparent severity of the environmental conditions in the McMurdo Dry Valleys, Eastern Antarctica, recent phylogenetic studies conducted on mineral soil samples have revealed the presence of a wide diversity of microorganisms, with actinobacteria representing one of the largest phylotypic groups. Previous metagenomic studies have shown that the majority of Antarctic actinobacterial populations are classified as ,uncultured'. In this study, we assessed the diversity of actinobacteria in Antarctic cold desert soils by complementing traditional culture-based techniques with a metagenomic study. Phylogenetic analysis of clones generated with actinobacterium- and streptomycete-specific PCR primers revealed that the majority of the phylotypes were most closely related to uncultured Pseudonocardia and Nocardioides species. Phylotypes most closely related to a number of rarer actinobacteria genera, including Geodermatophilus, Modestobacter and Sporichthya, were also identified. While complementary culture-dependent studies isolated a number of Nocardia and Pseudonocardia species, the majority of the cultured isolates (> 80%) were Streptomyces species , although phylotypes affiliated to the genus Streptomyces were detected at a low frequency in the metagenomic study. This study confirms that Antarctic Dry Valley desert soil harbours highly diverse actinobacterial communities and suggests that many of the phylotypes identified may represent novel, uncultured species. [source]

Occurrence and survival of potato scab pathogens (Streptomyces species) on tuber lesions: quick diagnosis based on a PCR-based assay

PLANT PATHOLOGY, Issue 3 2004
M. J. Lehtonen
A time-saving and cost-effective polymerase chain reaction (PCR)-based method was developed for species-specific detection of the scab pathogens (Streptomyces scabies and S. turgidiscabies) prevalent in potato (Solanum tuberosum) in northern Scandinavia. Species specificity of primers was verified using a collection of previously characterized Streptomyces strains isolated from potato scab lesions in Finland and Sweden. A total of 1245 scab lesions was tested from potato cvs Matilda and Sabina grown in the field in two geographic regions of Finland in 2000 and 2001. Freshly harvested or stored potato tubers were incubated at room temperature (18,21°C) under humid conditions for a few days. Bacterial growth was collected from scab lesions for DNA isolation and PCR. The two scab pathogens were detected in the same potato fields, tubers and scab lesions. The relative incidence of S. scabies was high in freshly harvested tubers but was much lower than that of S. turgidiscabies following storage. Both pathogens were seed-transmitted in Matilda and Sabina after 24 weeks of storage at 4°C. [source]

Differences in host range, pathogenicity to potato cultivars and response to soil temperature among Streptomyces species causing common and netted scab in France

PLANT PATHOLOGY, Issue 1 2000
Bouchek-Mechiche
The pathogenicity and ecology of some isolates representative of the four main Streptomyces species (S. scabies, S. europaeiscabiei, S. stelliscabiei and S. reticuliscabiei) identified as pathogenic to potato tubers were investigated. Three pathogenicity groups could be distinguished. Group 1 included all isolates of S. scabies, S. europaeiscabiei and S. stelliscabiei from common scab lesions of potato and other susceptible root crops. All these produced similar symptoms and were pathogenic to potato, carrot and radish. Group 2 included all isolates from S. reticuliscabiei netted scab lesions; they were pathogenic to both tubers and roots of only a few potato cultivars, and did not infect carrot or radish. Group 3 included three isolates of S. europaeiscabiei from netted scab lesions on cv. Bintje, which produced either common or netted scab symptoms depending on the potato cultivar or plant species. In an experiment on a few isolates from each of the three groups, held at various soil temperature regimes, the three from group 1 were most pathogenic at higher temperatures (20°C or 20/30°C), the two from group 2 were most pathogenic at a lower temperature (17°C). The group 3 isolate caused netted scab symptoms on susceptible cultivars at low temperatures (, 20°C) and deep-pitted lesions at higher temperatures. Since the groups identified differ in ecological requirements, it is important to adapt the control methods to the pathogenic species present in the soil. [source]

Review: Alternatives to synthetic fungicides for Botrytis cinerea management in vineyards

AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2010
M.A. JACOMETTI
Abstract Botrytis cinerea (Pers.: Fr), the causal agent of botrytis bunch rot, is an important disease of grapevines worldwide, with canopy management and the prophylactic use of fungicides being the most common control methods. The latter has resulted in fungicide resistance and is increasingly raising concerns regarding residues in wine and effects on human and environmental health. Research-led alternatives to this practice are beginning to emerge, including a range of biotic and abiotic treatments that induce vine resistance to B. cinerea and inundative applications of biological control agents such as Trichoderma, Bacillus, Ulocladium and Streptomyces species. Also, habitat manipulation techniques that aim to improve the effectiveness of naturally occurring biological control are being developed using mulches brought into the vineyard, as well as mulched cover crops. These can accelerate decomposition of botrytis mycelium and sclerotia on the vineyard floor in winter. The challenges of these different techniques and the prospects for habitat manipulation for this fungal disease are discussed. Extensive tables on synthetic fungicides, biofungicides, essential oils and plant extracts effective against B. cinerea are included. [source]

Involvement of alanine 103 residue in kinetic and physicochemical properties of glucose isomerases from Streptomyces species

BIOTECHNOLOGY JOURNAL, Issue 2 2007
Mohamed Ali Borgi
Abstract The Ala103 to Gly mutation, introduced within the glucose isomerase from Streptomyces sp. SK (SKGI) decreased its catalytic efficiency (kcat/Km) toward D -glucose from 7.1 to 3 mM,1 min,1. The reverse counterpart replacement Gly103Ala introduced into the glucose isomerase of Streptomyces olivochromogenes (SOGI) considerably improved its catalytic efficiency to be 6.7 instead of 3.2 mM,1 min,1. This later mutation also increased the half-life time of the enzyme from 70 to 95 min at 80°C and mainly modified its pH profile. These results provide evidence that the residue Ala103 plays an essential role in the kinetic and physicochemical properties of glucose isomerases from Streptomyces species. [source]