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At least 19 recordsLinked to original sources
PubMed1995

[The investigation on actinomycete population and resources in some areas in Yunnan. IX. The actinomycetes in the west and the northeast of Yunnan].

Two hundred of soil samples of primeval forest, secondary forest, wasteland, nonirrigated farmland, vegetable farmland and paddy farmland were collected from both the west and the northeast of Yunnan in February, 1989. The actinomycetes in the samples were isolated and identified by various methods. This paper discussed the actinomycete population and its difference in the both areas of Yunnan.

Actinomyces↗
PubMed1984

Malate dehydrogenases from actinomycetes: structural comparison of Thermoactinomyces enzyme with other actinomycete and Bacillus enzymes.

Malate dehydrogenases from bacteria belonging to the genus Thermoactinomyces are tetrameric, like those from Bacillus spp., and exhibit a high degree of structural homology to Bacillus malate dehydrogenase as judged by immunological cross-reactivity. Malate dehydrogenases from other actinomycetes are dimers and do not cross-react with antibodies to Bacillus malate dehydrogenase.

Bacillus↗
PubMed1997

Analysis of actinomycete communities by specific amplification of genes encoding 16S rRNA and gel-electrophoretic separation in denaturing gradients.

A group-specific primer, F243 (positions 226 to 243, Escherichia coli numbering), was developed by comparison of sequences of genes encoding 16S rRNA (16S rDNA) for the detection of actinomycetes in the environment with PCR and temperature or denaturing gradient gel electrophoresis (TGGE or DGGE, respectively). The specificity of the forward primer in combination with different reverse ones was tested with genomic DNA from a variety of bacterial strains. Most actinomycetes investigated could be separated by TGGE and DGGE, with both techniques giving similar results. Two strategies were employed to study natural microbial communities. First, we used the selective amplification of actinomycete sequences (E. coli positions 226 to 528) for direct analysis of the products in denaturing gradients. Second, a nested PCR providing actinomycete-specific fragments (E. coli positions 226 to 1401) was used which served as template for a PCR when conserved primers were used. The products (E. coli positions 968 to 1401) of this indirect approach were then separated by use of gradient gels. Both approaches allowed detection of actinomycete communities in soil. The second strategy allowed the estimation of the relative abundance of actinomycetes within the bacterial community. Mixtures of PCR-derived 16S rDNA fragments were used as model communities consisting of five actinomycetes and five other bacterial species. Actinomycete products were obtained over a 100-fold dilution range of the actinomycete DNA in the model community by specific PCR; detection of the diluted actinomycete DNA was not possible when conserved primers were used. The methods tested for detection were applied to monitor actinomycete community changes in potato rhizosphere and to investigate actinomycete diversity in different soils.

Actinomycetales↗
PubMed2001

Insecticidal activity of selected actinomycete strains against the Egyptian cotton leaf worm Spodoptera littoralis (Lepidoptera: Noctuidae).

Actinomycete strains isolated from soil samples of Saudi Arabia and Egypt were used in the present study to investigate the biological activity of their secondary metabolites on the cotton leaf worm Spodoptera littoralis. Secondary metabolites of 41 strains were given to the newly molted last instar larvae through the food plant (Castor leaves). Many actinomycete strains (58% of all) caused larval mortality ranging from 10-60%. Treatments with strains no. 7, 36, 41 resulted in significant prolongation of larval life (10.0 +/- 1.26, 11.5 +/- 0.7 and 10.6 +/- 1.5 days Vs 9.2 +/- 0.4 of controls). Pupation was affected by the actinomycete treatments (60.1% of all). Success of pupation ranged only from 20 to 80%, depending on the efficiency of the tested secondary metabolites. In contrast, the pupal duration had not been significantly affected but 19.5% of actinomycete strains halted the pupation, because different percentages of pupal deformities were counted (100% pupal deformation after treatment with secondary metabolites of actinomycete strains no. 36). In addition, considerable lethal effect of some actinomycetes were observed on pupae (60, 42.9, 40, 50 and 66.6% pupal mortalities caused by secondary metabolites of strains: 2, 9, 16, 18 and 26, respectively). Secondary metabolites of 34.1% of all actinomycete strains blocked the adult emergence. Depending on the available data, Streptomyces and Streptoverticillum were found the most potent actinomycetes affecting the biological and physiological criteria of the present insect species.

Actinomycetales↗
PubMed1977

[Investigations about cause of specific replant disease of fruit trees. VI. Proof of actinomycetes in feeder roots of apple seedlings in soils with different digrees of soil sickness (author's transl)].

Microscopic analysis of longitudinal sections of feeder roots of apple seedlings from soil with experimentally prepared different degrees of soil sickness led to the following results: 1. A colonization of root-barks by actinomycetes could be pointed out in injured and in macroscopic not visible injured feeder roots of apple seedlings from sick soil. 2. The frequency of the colonization of root-pieces of the two highest root classes was in the sick soil at 47.3% and in the two soils with a less degree of soil sickness at 32.4%. In the non-sick soil the root were at a frequency of 0.3% nearly free from actinomycetes. 3. Feeder roots colonizated by actinomycetes showed injuries in the cell-bandage. Increasing injuries of the roots were obtained with increasing intensity of colonization by actinomycetes. In heavy injured feeder roots the proof of actinomycetes was difficult or no more possible. As the share of heavy injured roots was increasing with increasing degree of soil sickness can be supposed that the real frequency of root colonization by actinomycetes is substantially higher than it was observed in roots seeming to be healthy macroscopically. 4. The results obtained support our hypothesis that soil sickness of apple trees is caused by actinomycetes. The injuries of the roots appearing as a consequence of the colonization may explain both, the soil sickness in the case of replanting and the development of soil sickness in growing apple plantations. 5. Since until now there is no proof that actinomycetes cause injuries in roots of fruit-trees further examinations have to be aspired to confirm our results.

Actinomycetales↗
PubMed2001

Aquatic Actinomycete-Fungal Interactions and Their Effects on Organic Matter Decomposition: A Microcosm Study.

The role of fungi in the decomposition of organic matter in streams has been well examined, although the role of bacterial antagonists in such processes has gained little attention. To examine bacterial-fungal interactions, experiments involving pairwise combinations of four actinomycete isolates (A1+ and A2+ could remove chitin from chitin-containing media, and A1? and A2? could not) and two fungal isolates (F+ a true fungus, F? an oomycote) were conducted. For each bacterial-fungal combination, 250-ml microcosms were sampled at 8 day intervals for 32 days. Microbial biomass and organic matter, as well as the activities of five extracellular enzymes, were measured. Each experiment consisted of a control group and four treatment groups. Controls comprised sterilized stream water and macrophytes. The first treatment was inoculated with only actinomycetes (~103 cells ml-1), the second treatment was inoculated with only fungi (~102 cells ml-1), the third group was inoculated simultaneously with actinomycetes and fungi, and the fourth group was inoculated with actinomycetes 2 days after fungal establishment. For all combinations, the lowest rates of organic matter decomposition were expected in the controls, as a result of only physical degradation. In contrast, the greatest rates of organic matter decomposition were predicted in treatments inoculated with F+ 2 days prior to A1? or A2?. Greater than 50% of the organic matter was decomposed in each of the fungal treatments. Fungal-actinomycete interactions resulted in reduced fungal biomass relative to the fungal-only treatments. However, when inoculated 2 days apart, combinations of F? and actinomycetes resulted in enhanced rates of organic matter decomposition, as well as greater levels of extracellular enzyme activities. These results demonstrate that actinomycete-fungal interactions and their colonization dynamics affect the accumulation of biomass, extracellular enzyme activities, and rates of organic matter decomposition.

Journal Article↗
PubMed1982

The relationship of genital tract actinomycetes and the development of pelvic inflammatory disease.

As a corollary to a case-control study evaluating the risk of pelvic inflammatory disease (PID) among users of an intrauterine contraceptive device (IUD), Papanicolaou smears were studied to detect the presence of actinomycetes. Forty-six PID case patients and 108 control patients were included in the corollary study. The presence of actinomycetes was noted only among current or past wearers of an IUD. Women with actinomycetes present on Papanicolaou smear had a 3.6-fold risk of hospitalization for PID, as compared to women without actinomycetes. This trend persisted when only IUD users were evaluated. Of patients with PID who had actinomycetes noted on the Papanicolaou smear, 87 1/2% had a tuboovarian abscess, compared to 28.9% of patients without actinomycetes. In addition, patients with actinomycetes present had PID treated surgically more frequently.

Abscess↗