Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ACTINOMYCETES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
PubMed1994

[Effect of calcium ions on the differentiation of actinomycetes].

The influence of Ca2+ on the formation of the aerial mycelium in 23 actinomycete strains was studied. It was shown that in concentrations up to 5 mM exogenous Ca2+ induced the formation of the aerial mycelium in 11 out of the 23 actinomycete strains tested. The Ca2+ channel blockers (verapamil and nifedipine), calmodulin inhibitor (chlorpromazine) and Ca2+ chelator (EGTA) inhibited the aerial mycelium formation in 3 streptomycete strains out of the 23 actinomycetes. Chlorpromazine and nifedipine proved to be the most active inhibitors when used in concentrations of 0.2 to 2.5 mumol/disk. The Ca2+ concentrations of 5 mM were found to stimulate the formation of the submerged spores in S. hygroscopicus 155. The activity of ATP synthase was stimulated in the aerial and submerged spores after the Ca2+ uptake.

Actinomycetales↗
PubMedDate not supplied

[Peptidases of preparations of proteolytic enzymes from several species of bacteria, molds and actinomycetes].

The activity of carboxy- and aminopeptidases of enzymic preparations obtained from bacteria Bacillus subtilis 1 M, 17, Bacillus mesentericus 100/26, 100/56, 16; Pseudomonas aeruginosa 1/7a, 1/4; Bacillus thermophilicus S. sp. nov B-22, moulds Aspergillus oryzae 1-746, Aspergillus flavus 716 and actinomycete Streptomyces griseus 32-13 was studied. In the bacterial preparations the proteolytic activity was 1.5-2.5 times lower than in the fungal and actinomycete preparations. The carboxypeptidase activity of bacterial preparations was comparable with that of the moulds and by one order of magnitude lower than that of the actinomycete. The aminopeptidase activity of the bacterial preparations was different; however, it was comparable with that of the moulds and was higher than that in some cases. In the Streptomyces preparation the aminopeptidase activity was significantly higher than in the bacterial and fungal preparations. In most preparations Co2+ and Mn2+ influenced the activity of carboxy- and amino-peptidases. This suggests that these proteins can be referred to metal enzymes.

Aspergillus flavus↗
PubMed1996

Genetic tools in pathogenic nocardioform actinomycetes.

Nocardioform actinomycetes are Gram-positive bacteria with high G+C content. Several species of Mycobacterium, Corynebacterium, Nocardia and Rhodococcus are important human or animal pathogens. Transposon mutagenesis and homologous recombination are powerful genetic tools used for the identification of pathogenicity determinants. Transposable elements with potential application to mutagenize pathogenic nocardioform actinomycetes are described. Homologous recombination experiments which have been recently achieved in mycobacteria and related actinomycetes are commented on.

Actinomycetales↗
PubMed1977

Actinomycetes of the genus Streptomyces in soil from Syria.

Species identification and antagonistic properties of 55 actinomycete strains isolated from Syrian soil were studied. The actinomycete strains belonged to 22 species, of which most abundantly represented were Streptomyces antimycoticus, S. rubiginosohelvolus, S. macrosporeus and S. coerulescens. Actinomycetes belonging to 16 species exhibited antagonism in relation to Gram-positive and Gram-negative bacteria, fungi and neoplastic cells.

Anti-Bacterial Agents↗
PubMed1963

Selective isolation of aerobic Actinomycetes.

The composition of an arginine-glycerol-salt medium (AGS), suitable for the selective isolation of aerobic actinomycetes, was given. When soil samples were treated with calcium carbonate and plated on the AGS medium, higher total and relative plate counts of actinomycetes were obtained than when other media and methods were used.

Actinobacteria↗
PubMed1998

Utilization of quinate and p-hydroxybenzoate by actinomycetes: key enzymes and taxonomic relevance.

474 strains of the actinomycete genera Streptomyces (including species of the former genera Chainia and Streptoverticillium), Pseudonocardia and Micromonospora were examined for their ability to degrade quinate (Q) and p-hydroxybenzoate (pHB); selected strains were also tested for their capacity to catabolize benzoate (B). Whereas in the case of Q (5-10 g/l of a mineral salts agar medium) the growth response signalizes assimilation, pHB has to be supplied in lower concentration (routinely 0.3 g/l together with small amounts of peptone and yeast extract in liquid broth), and its degradation has to be determined spectrophotometrically. 27% of the streptomycete strains were able to grow with Q, and 57% with pHB. The three strains of "Chainia" that were tested metabolized Q and pHB, but none of the fourty species of "Streptoverticillium" showed this ability. 80% of the 30 strains of Psn. autotrophica grew with Q, and 100% degraded pHB and B. Two of the five Micromonospora strains gave a positive response with pHB, but not with Q.-Toluene treated cells (preincubated with Q, pHB or B, respectively) gave a positive Rothera reaction with protocatechuate or catechol respectively, thus demonstrating that these organisms employed the beta-ketoadipate pathway (orthofission) for the degradation of Q, pHB and B. The assay of five relevant enzymes in cell-free extracts of nine selected organisms showed that in nocardioform actinomycetes (Pseudonocardia, Rhodococcus) all enzymes of the protocatechuate branch of the ketoadipate pathway seem to be induced by beta-ketoadipate as demonstrated here for protocatechuate-3,4-dioxygenase. In contrast, in Streptomyces this enzyme appears to be induced by its substrate, protocatechuate, whereas the regulation of the other enzymes of this pathway remains to be elucidated.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2002

Estimation of growth inhibition by copper and cadmium in heavy metal tolerant actinomycetes.

A new isothermic model of actinomycetes growth in presence of toxic concentrations of Cd(2+) and Cu(2+) is described. Microbial growth inhibition, displayed as a decrease of biomass, can be correlated with the increase of cadmium(II) or copper(II) concentration in the medium. The reciprocal dry biomass against metal concentration showed a linear correlation higher than 0.9 in tested strains. The mathematical model can be useful to predict the behavior of actinomycetes at inhibitory concentrations of copper(II) and cadmium(II) in large screening procedures.

Actinomycetales↗
PubMed2004

Glucose metabolism in the antibiotic producing actinomycete Nonomuraea sp. ATCC 39727.

The actinomycete Nonomuraea sp. ATCC 39727, producer of the glycopeptide A40926 that is used as precursor for the novel antibiotic dalbavancin, has an unusual carbon metabolism. Glucose is primarily metabolized via the Entner-Doudoroff (ED) pathway, although the energetically more favorable Embden-Meyerhof-Parnas (EMP) pathway is present in this organism. Moreover, Nonomuraea utilizes a PPi-dependent phosphofructokinase, an enzyme that has been connected with anaerobic metabolism in eukaryotes and higher plants, but recently has been recognized in several actinomycetes. In order to study its primary carbon metabolism in further detail, Nonomuraea was cultivated with [1-13C] glucose as the only carbon source and the 13C-labeling patterns of proteinogenic amino acids were determined by GC-MS analysis. Through this method, the fluxes in the central carbon metabolism during balanced growth were estimated. Moreover, a shift in the label incorporation pattern was observed in connection with phosphate limitation and increased antibiotic productivity in Nonomuraea. The shift indicated an increased flux through the EMP pathway at the expense of the flux through the ED pathway, a suggestion that was supported by alterations in intracellular metabolite levels during phosphate limitation. In contrast, expression levels of genes encoding enzymes in the ED and EMP pathways were not affected by phosphate limitation.

Actinobacteria↗
PubMed1984

Inducers of both cytodifferentiation and anthracycline biosynthesis of Streptomyces griseus and their occurrence in actinomycetes and other microorganisms.

Many taxonomically different strains of actinomycetes as well as several other procaryotic and eucaryotic microorganisms were shown to produce inducers of cytodifferentiation and anthracycline biosynthesis being active towards blocked mutant ZIMET 43682 of Streptomyces griseus. 37 out of 40 strains of the species of S. griseus (92.5%) yielding different kinds of antibiotics were able to induce both the formation of aerial mycelium in the indicator strain ZIMET 43682 concomitant with the biosynthesis of anthracycline antibiotics. 80 (26.3%) out of 304 strains belonging to 94 different Streptomyces species were also producers of inducing agents. Among 77 strains of actinomycetes belonging to 28 different genera being apart from Streptomyces, 12 strains displayed inducing activity (15.6%). The results obtained so far support the conclusion that the formation of inducing agents was neither associated with a particular species of Streptomyces nor its capacity to produce a given antibiotic. The occurrence of inducers has been observed even with members of other genera. Few strains were capable of inducing only one of the differentiation-associated functions. Some strains of Streptomyces species produced at least two different kinds of inducers discernible by their Rf values on TLC.

Anti-Bacterial Agents↗
PubMed2004

Antifungal activity of actinomycetes from Cuban soils.

This study reports on the capacity of actinomycete strains isolated from Cuban soils to produce antifungal agents. The antimicrobial activities were determined by susceptibility disk assay methods. We isolated 563 different actinomycetes and 286 produced compounds with antifungal activity. Our screening method indicated the presence of many possible polyene macrolide antibiotics and the important antifungal activity in the soils rich in minerals.

Actinobacteria↗
PubMed1988

Biotyping of aerobic actinomycetes by modified killer system.

Forty-four yeasts belonging to the genera Pichia, Candida, Saccharomyces and Kluyveromyces were tested for their potential killer effect on 13 aerobic actinomycetes (6 Nocardia asteroides, 1 N. brasiliensis, 1 N. caviae and 5 Actinomadura madurae). Only a few yeast strains did not display any killer activity against the aerobic actinomycetes studied, thus confirming that the killer phenomenon is widespread among microorganisms. For epidemiological purposes, a killer system was developed. According to their susceptibility to the 9 killer yeasts chosen, it was possible to differentiate the Nocardia and Actinomadura isolates into biotypes. Fitting conditions of the killer system to potential sensitive microorganisms with different characteristics of growth are also discussed.

Actinomycetaceae↗
PubMed1984

Actinomycetes as the causative organism of osteomyelitis in sickle cell disease.

The case of a 17-year-old girl with sickle cell anaemia who presented with extensive osteomyelitis due to actinomycetes is reported. Osteomyelitis in the long bones due to actinomycosis is extremely rare. A review of the literature reveals only six cases in which actinomycetes have been isolated from lesions affecting a long bone. The occurrence of this condition in sickle cell haemoglobinopathy has not been previously reported.

Actinomycosis↗
PubMed1976

Occurrence of pppApp-synthesizing activity in actinomycetes and isolation of purine nucleotide pyrophosphotransferase.

The occurrence of adenosine 5'-triphosphate-3'diphosphate-synthesizing activity was detected in five strains of actinomycetes; Streptomyces morookaensis, Streptomyces aspergilloides, Streptomyces hachijoensis, tactinomyces violascens and Streptoverticillium septatum, out of 825 strains of actinomycetes, bacteria, fungi and fungi imperficti. Purine nucleotide pyrophosphotransferase were extracellularly excreted associating with the cell growth, and were purified partially or to apparent homogeneiety from the culture filtrate. The enzymes are a monomeric protein with molecular weight of 18,000-26,000 and synthesize adenosine, guanosine and inosine 5'-phosphate (mono, di or tri)-3'-diphosphate such as pApp, ppA pp, pppApp, pGpp, ppGpp, pppGpp, and pppIpp by transferring a pyrophosphoryl group from the 5'-position of ATP, dATP and ppApp to the 3'-position of purine nucleotides in the presence of a divalent cation and in alkaline state.

Actinomycetales↗
PubMed1981

Survey of human pathogenic actinomycetes and fungi in soil from Rome and other Italian areas.

As part of a study sponsored by the Ministry of Health of Italy, a research program on pathogenic actinomycetes, keratinophilic and pathogenic fungi in soil was carried out. Two hundred soil samples, collected from different areas of the city of Rome, Calabria, Emilia Romagna, Latium, Apulia, Sardinia, Sicily, Tuscany and Umbria, were examined by several techniques to detect the widest possible variety of pathogenic actinomycetes and fungi. Seven isolates of Nocardia asteroides, four of Actinomadura madurae and one of Nocardiopsis dassonvillei were isolated for the first time from soil in Italy. In addition, numerous isolates of Petriellidium boydii, Aspergillus fumigatus, A. flavus, A. niger and keratinophilic fungi of the genera Microsporum, Trichophyton and Chrysosporium were also recovered.

Aspergillus↗
PubMed1991

Occurrence and significance of precipitating antibodies against thermophilic actinomycetes in the sera of dairy herd workers, Nangali, Delhi.

The study was prompted by the lack of information on the role of thermophilic actinomycetes in hypersensitivity pneumonitis in India. It reports the occurrence of precipitating antibodies against clinically important thermophilic actinomycetes in the sera of a population sample of dairy herd workers, Nangali, Delhi. Of 112 workers investigated, 28 (25%) showed precipitins against Faenia rectivirgula, 4 (3.2%) against Saccharomonospora viridis, 2 against Thermoactinomyces thalpophilus and one each against T. vulgaris and T. sacchari. The results of enzyme-linked immunosorbent assay (ELISA) indicated that IgG antibody activity against F. rectivirgula was significantly higher in the symptomatic group than in the asymptomatic group (p less than 0.05) of workers and the controls (p less than 0.01). Significant difference in F. rectivirgula IgG activity was also obtained between the precipitin-positive symptomatic group and the precipitin-positive asymptomatic group (p less than 0.05). In strong contrast, the IgG antibody activity against T. thalpophilus was found to be uniformly low. A limited aeromicrobiological sampling of the dairy farm revealed S. viridis (55.8%) to be the commonest species followed by T. vulgaris (19.2%), T. thalpophilus (18.5%), F. rectivirgula (5%) and T. sacchari (1.5%). On the basis of suggestive clinical and laboratory findings, farmer's lung disease was suspected in four dairy herd workers. A comprehensive clinical evaluation including pulmonary function studies on the dairy herd workers and their long-term follow-up is indicated to determine the extent of respiratory morbidity caused by F. rectivirgula, S. viridis, T. thalpophilus, T. sacchari and T. vulgaris in India.

Adult↗
PubMed1990

The chromosomal integration site of the Streptomyces element pSAM2 overlaps a putative tRNA gene conserved among actinomycetes.

The pSAM2 element of Streptomyces ambofaciens integrates site-specifically in the genome of different Streptomyces species by recombination between a 58 bp sequence common to the plasmid (attP) and the chromosome (attB). Southern hybridization analysis showed that sequences similar to the pSAM2 attB site were found in other actinomycetes (Mycobacterium, Nocardia, Micromonospora) as well as unrelated bacteria (Bacillus circulans, Escherichia coli, Clostridium botulinum, Bordetella pertussis, and Legionella pneumophila). Hybridizing fragments from B. circulans and Mycobacterium tuberculosis were cloned and sequenced. Comparison of these sequences with the sequence of the integration zone of S. ambofaciens revealed a conserved region of 76 bp which overlapped with the attB site. This conserved sequence was similar to the Salmonella typhimurium and E. coli tRNA(pro1) genes as well as a number of eucaryotic tRNA genes and had a proline-tRNA-like cloverleaf structure. Furthermore, the Streptomyces lividans attB site of the Streptomyces glaucescens element pIJ408 was also found to overlap a potential tRNA gene (tRNA(thr)). We note here that these two putative tRNA genes as well as those which overlap the attB site of the elements SLP1 of Streptomyces coelicolor and pMEA100 of Nocardia mediterranei all contain the site where integrative recombination takes place. These presumptive actinomycete tRNA genes lack the 3' terminal CCA sequence found in most procaryotic tRNA genes.

Actinomycetales↗
PubMed1994

Occurrence of thermophilic actinomycetes in natural substrates in Nigeria.

Thermophilic actinomycetes were isolated from 163 (48.95%) of 333 samples of vegetable substrates and soil from different sites in Anambra and Enugu States in Nigeria. Thermoactinomyces (Tha.) vulgaris was the most common, occurring in 32.4% of samples while Tha. thalpophilus was isolated from 20.1%. Tha. sacchari, Saccharomonospora (Sam.) viridis and Saccharopolyspora (Sap.) rectivirgula were isolated from 3-10.5% of the samples examined. Streptomyces (Stm.) thermovulgaris occurred in 2.7% and Thermomonospora spp. in 0.6% of samples. Except for Stm. thermovulgaris and, perhaps, Thermomonospora spp., all the species isolated are known to be allergenic in man. The five known allergenic species were abundant in hay and maize silage. T. vulgaris and T. thalpophilus were also frequently isolated from rice straw. Tha. vulgaris, Tha. thalpophilus and Sap. rectivirgula were all most numerous in hay while Tha. sacchari was most numerous in maize silage. The widespread occurrence of thermophilic actinomycetes in Nigeria emphasizes the need for investigation of their role in allergic respiratory disorders.

Actinomycetales↗
PubMed1989

Actinomycetes in pyogenic liver abscess.

Three patients with pyogenic liver abscesses had actinomycetes cultured from aspirated pus, although it is unusual for hepatic actinomycosis to present in this way. The spectrum of bacteria found in liver abscesses appears to be changing, with the increased isolation of anaerobes partly due to improved techniques. It is important to recognise the presence of actinomycetes so that appropriate chemotherapy can be given.

Actinomyces↗