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PubMed1983

Prevalence of viridans streptococci exhibiting lactose-inhibitable coaggregation with oral actinomycetes.

Fresh oral isolates from human dental plaque were selected on the basis of their spherical morphology. In a double-blind experiment, their species identity and ability to coaggregate with human oral Actinomyces viscosus and Actinomyces naeslundii were determined. Of the 110 isolates characterized, 30 were identified as either Streptococcus mutans, Streptococcus anginosus-constellatus, or Veillonella parvula; none of these coaggregated with the actinomycetes. The remaining 80 isolates were identified as Streptococcus sanguis, Streptococcus mitis, Streptococcus MG-intermedius, or Streptococcus morbillorum. Of these 49 isolates (61%) coaggregated with actinomycetes, and nearly 90% (43 of 49 isolates) exhibited lactose-inhibitable coaggregations. Compared with previously characterized coaggregation properties determined with stock culture strains of streptococci, 82% of the fresh isolates exhibited identical coaggregations. The other 18% made up a new coaggregation group that possessed a related lactose-inhibitable coaggregation pattern. Thus, most fresh isolates that coaggregated exhibited lactose-inhibitable coaggregations with human oral actinomycetes. It is suggested that these coaggregations are mediated by a network of lectin-carbohydrate interactions similar to those already characterized in previous studies with stock cultures of actinomycetes and streptococci.

Actinomycetales↗

PubMed1982

Comparison of methods for isolation and enumeration of thermophilic actinomycetes from dust.

Thermophilic actinomycetes are the primary sensitizing agents in farmer's lung disease. We compared dilution pour-plate and spread-plate methods for their usefulness in enumerating thermophilic actinomycetes in moldy silage dust and evaluated the ability of a nonquantitative gravity settling technique to recover thermophilic actinomycetes from moldy silage. Spread plates and pour plates yielded similar estimates of total thermophiles. Higher counts were observed on spread plates (P less than 0.05) for Thermoactinomyces candidus, Micropolyspora faeni, and Saccharomonospora viridis. M. faeni and S. viridis were less efficient than T. candidus in breaking through the agar of pour plates to form colonies which could be identified. Coefficients of variability were less than 10% for the two methods. The relative proportion of organisms recovered by the settling method correlated well with that recovered on spread plates for M. faeni (r = 0.79), S. viridis (r = 0.88), and Thermomonospora spp. (r = 0.79), but not well for T. candidus (r = 0.28). When sophisticated air-sampling equipment is not available, dilution spread plates of dust washings provide a reproducible method for enumerating a broad range of thermophilic actinomycetes of interest. The gravity settling method is a simple, rapid alternative when isolation is all that is required.

Agriculture↗

PubMed1998

Clinical application of PCR-restriction enzyme pattern analysis for rapid identification of aerobic actinomycete isolates.

The accuracy and practicality of PCR-restriction enzyme pattern analysis (PRA) for routine identification of aerobic actinomycete clinical isolates were evaluated for 299 cultures submitted to the Mycobacteria/Nocardia Laboratory at the University of Texas Health Center at Tyler. PRA identification using an amplified 439-bp segment (amplicon) of the 65-kDa heat shock protein gene was compared to identification by traditional methods, including growth characteristics, susceptibility patterns, biochemical testing, and high-performance liquid chromatography analysis. Microbiological examination of six cultures ruled out aerobic actinomycetes, and they were omitted from the study. Amplicons were analyzed with BstEII, HaeIII, MspI, HinfI, and BsaHI. When necessary, AciI, HhaI, and NarI were also used. From March 1995 through May 1997 (27 months), 274 of the remaining 293 (93.5%) isolates were accurately identified by PRA. Major diagnostic groups included 170 mycobacteria, 93 nocardiae, and 30 other aerobic actinomycetes. Mixed cultures were readily recognized by PRA, including a wound culture that contained two Nocardia taxa that were indistinguishable morphologically. Mycobacterium mucogenicum was identified in three cultures heavily contaminated with gram-positive cocci. The 19 isolates that produced PRA patterns that did not match those in the current PRA database were differentiated into 8 Mycobacterium species and 11 other aerobic actinomycetes by the presence or absence of BstEII recognition sites. Identification of 15 of these 19 isolates was also equivocal by traditional methods. PRA results were reportable within 2 to 5 working days and were as accurate as and faster and less expensive to obtain than those of traditional methods.

Actinomycetales↗

PubMed2005

Actinomycetes as host cells for production of recombinant proteins.

Actinomycetes (Actinobacteria) are highly attractive as cell factories or bioreactors for applications in industrial, agricultural, environmental, and pharmaceutical fields. Genome sequencing of several species of actinomycetes has paved the way for biochemical and structural analysis of important proteins and the production of such proteins as recombinants on a commercial scale. In this regard, there is a need for improved expression vectors that will be applicable to actinomycetes. Recent advancements in gene expression systems, knowledge regarding the intracellular environment, and identification and characterization of plasmids has made it possible to develop practicable recombinant expression systems in actinomycetes as described in this review.

Journal Article↗

PubMed2003

Isolation of actinomycetes from termites' guts.

Actinomycetes could be isolated efficiently on a defatted wood powder medium from the guts of various species of termites. The actinomycete flora in the termites' guts depended largely on the area in which the termites naturally occur. In termites from the same area, the actinomycete flora changed depending on the taxonomic difference between termite species. Some actinomycetes isolated from termites' guts grew satisfactorily on lignin-related media, and the others grew on cellulose-related media.

Actinobacteria↗

PubMed2004

Isolation of flavohemoglobin from the actinomycete Streptomyces antibioticus grown without external nitric oxide stress.

A flavocytochrome protein was isolated from the actinomycete Streptomyces antibioticus. The purified protein contained protoheme and FAD, and its M(r) was estimated to be 52000. The absorption spectra in its resting oxidized, dithionite-reduced, carbon monoxide-bound, and oxygenated (O(2)-bound) forms were characteristic of those of flavohemoglobin (Fhb). The N-terminal amino acid sequence showed high identities to those of other Fhb's. Furthermore, the actinomycete flavocytochrome scavenged nitric oxide in the presence of NADH. These results demonstrated that the flavocytochrome is the first Fhb purified from actinomycetes. The actinomycete Fhb was produced in S. antibioticus cells in large amounts without any external nitric oxide (NO) stress, which is indicative of a physiological function of Fhb other than detoxification of NO.

Amino Acid Sequence↗

PubMed1999

Chromium-resistant soil actinomycetes: their tolerance to other metals and antibiotics.

Chromium occurs widely in most soils, but generally in trace amounts. Actinomycetes, one of the important components of the microbial population in soils interact with a variety of metals including chromium. This study was aimed to evaluate the tolerance of soil actinomycetes to Cr6+, other metals and antibiotics. Thirty-two actinomycete isolates were screened for their tolerance to Cr6+ on tryptone yeast extract agar medium supplemented with Cr6+ at concentrations ranging from 100 to 2000 micrograms ml-1. Thirteen Cr-tolerant isolates were selected on the basis of their growth at the highest concentration, but their performance was not satisfactory in Cr6+ containing liquid salts medium. Resistance of these isolates to other metals and antibiotics was assessed using agar-cup assay and disc diffusion technique, respectively. The sequence of metal toxicity for the actinomycete isolates was in the order Hg2+ > Ni2+ > Cu2+ > Co2+ > Cd2+, but the Cr6+ resistance of the isolates could not be correlated with their antibiotic-resistance profile.

Actinomycetales↗

PubMed2003

Isolation of new actinomycete strains for the screening of new bioactive compounds.

In order to facilitate the discovery of novel bioactive compounds from microorganisms, various techniques for isolation of new actinomycete strains have been attempted. Studies of the vertical distribution of actinomycetes in soil, isolation of actinomycetes from desert soils or fallen leaves, selective isolation of Kitasatospora strains using novobiocin or Actinoplanes strains using the chemotactic method, and the use of gellan gum as a solidifying agent were carried out. We discovered 9 novel bioactive compounds from actinomycete strains isolated under unusual conditions, and proposed two new genera, five new species and one new subspecies.

Actinobacteria↗

PubMed1994

Pathway engineering in secondary metabolite-producing actinomycetes.

Actinomycetes represent the microbial group richest in production of variable secondary metabolites. These mostly bioactive molecules are the end products of complex multistep biosynthetic pathways. Recent progress in the molecular genetics and biochemistry of the biosynthetic capacities of actinomycetes enables first attempts to redesign these pathways in a directed fashion. However, in contrast to several examples of designed biochemical improvement of primary metabolic processes in microorganisms, none of the products or strains derived from pathway engineering in actinomycetes discussed herein have reached pilot or production scale. The main reasons for this slow progress are the complicated pathways themselves, their complex regulation during the actinomycete cell cycle, and their uniqueness, as most pathways and products are specific for a strain rather than for a given species or larger taxonomic group. However, the modular use of a minimum of very similar enzymes and their conversion of similar intermediates to form the building blocks for the production of a maximum of divergent end products gives hope for the future application of these genetic models for the redesign of complex pathways for modified or new natural products. Several strategies that can be followed to reach this aim are discussed, mainly for the variable 6-deoxyhexose metabolism as an ubiquitously applicable example.

Actinomyces↗

PubMedDate not supplied

[Isolation of actinomycetes from soil using extremely high frequency radiation].

A new method employing extremely high frequencies (EHFs) is proposed for the selective isolation of actinomycetes from soil. The pretreatment of soil suspensions with EHF wavelengths of 5.6 and 7.1 mm led to a nonselective isolation of actinomycetes. At the same time, the irradiation of soil suspensions within wavelength bands of 3.8-5.8 and 8-11.5 mm considerably augmented the total number of isolated actinomycetes and increased the fraction of the isolated rare genera by 2 and 7 times, respectively. The rare actinomycete genera were represented by Actinomadura, Microtetraspora, Nonomuraea, Micromonospora, Amycolatopsis, Pseudonocardia, Saccharotrix, and Streptosporangium.

Actinomycetales↗

PubMedDate not supplied

[Actinomycetes in the rhizosphere of barley plants grown in the strongly acidic soddy podzolic soil].

The study of various factors (soil acidity, the variety of barley plants, and their developmental phases) on the rhizosphere actinomycete complex showed that it is soil acidity that substantially influences the population of rhizosphere actinomycetes. The effect of soil acidity was most likely due to the different tolerance of rhizosphere actinomycetes to high concentrations of the aluminum and hydrogen ions. The developmental phases of barley plants correlated with the population indices of only one genus of actinomycetes, Micromonospora.

Acids↗

PubMed2001

[Study on the application of quantitative analysis of cell-wall amino acids in actinomycetes classification].

This paper has collected 70 recognized type strains of actinomycete from home and abroad Microbiological culture collection centers. Adopting thin-layer chromatography and thin-layer chromatogram scanner methods to quantitatively analyze the composition of cell-wall amino acids in actinomycete. It has made comparison between quantitative results and qualitative ones. After a thorough discussion, a revision is made on the standard of dividing cell-wall types in actinomycete chemical classification, which has provided some original suggestion in hope of improving the research of actinomycete chemical classification.

Actinobacteria↗

PubMedDate not supplied

[New genus of actinomycetes: Excellospora gen. nov].

Morphological, cultural and physiological properties of two strains of soil thermophilic actinomycetes were studied. These strains were compared to the actinomycetes of related genera and were found to be close to Micropolyspora and Actinomadura. However, they differed from both genera by the structure of the sporiferous apparatus, from Micropolyspora by the type of the cell wall, and from Actinomadura by the fatty acid composition of lipids of the mycelium. A new genus of actinomycetes, Excellospora Agre a. Guzeva gen. nov., is suggested on the basis of this study. Two species belonging to the genus Micropolyspora are proposed to assign to the new genus as Excellospora viridinigra and Excellospora rubrobrunea. Since these strains differ from the aforementioned species by the traits used for differentiation of the species of actinomycetes, they are described as a new species of the new genus Excellospora Agre a. Guzeva gen. nov. sp. nov.

Hot Temperature↗

PubMedDate not supplied

[Actinomycete complexes in the rhizosphere of winter rye on soddy podzolic soil].

The structure of actinomycete complexes in the rhizosphere of winter rye (Secale cereale L.) varieties originating from different ecosystems and geographical zones was studied in field experiments on soddy podzolic soil. In addition to streptomycetes, the complexes studied contained actinomycetes of the genera Micromonospora and Streptosporangium, represented at high occurrence and comparable abundance rates. The rhizosphere of most of the studied rye varieties was dominated by micromonosporas. The antifungal potential of mycelial prokaryotes associated with winter rye was assessed. The taxonomic and functional structure of actinomycete complexes was shown to be similar in rye varieties originating from the nonchernozem zone of Russia. However, the actinomycete complex proved to be much different in the rye variety that developed in the steppe zone of the lower Volga region.

Actinobacteria↗

PubMed2004

[Study on actinomycetes population of alpine meadow soil in Qinghai].

Soil samples were collected from six kinds of soil in Haibei alpine meadow ecosystem during 2001 - 2002. More than 300 strains of actinomycete were isolated by five agar media. On the basis of morphological characteristics and some chemotaxonomic properties, the isolated strains were classified into different genera, such as Micromonospora, Nocardia, Saccharopolyspora, Promicromonospora, Streptomyces, and the Streptomyces strains were classified into seven groups. The result indicated that the biodiversity of actinomycetes in different soils and the actinomycetes abundance of different kinds showed significant differences. The activities of some enzymes produced by mesophilic and psychrophilic actinomycetes also discussed in this paper. It is found that many strains of streptomyces not only have some enzyme activities such as starch decomposition, nitrate deoxidization, gelatin utilization etc., but also have some inhibiting activities for fungi and bacteria offered to test, whereas the rare actinomyces showed low positive rate of enzyme activities and inhibiting activities for fungi and bacteria.

Actinobacteria↗

PubMed1983

[Growth and antimicrobial activity of an association of an actinomycete and a green alga].

During joint cultivation of the actinomycetes Streptomyces griseus (strains 65 and 744) isolated from the soil and the green algae Chlorella vulgaris larger amount of biomass as compared with solitary axenic culture have been shown. The relation of biomass of actinomycetes S. griseus strain 65 and S. griseus strain 744 and algae in the lichen-like experimentally formed thallom make up 42:1 and 40:1 relatively, i. e. the mass of actinomycetes forms 97-98% from the mass of thalloms. Actinomycetes in the associations with the algae accumulate larger amount of biomass that in the axenic cultures on corresponding medium, whereas the algae produce the same amount of the biomass as the axenic culture under the same conditions. The associations have the antimicrobic properties differed from the axenic cultures established.

Antibiosis↗

PubMedDate not supplied

[Fatty acids of actinomycete phospholipids].

The fatty acid composition of phospholipids was studied in different actinomycetes growing in two media in order to detect their biological activity. The total phospholipids of the actinomycetes did not differ qualitatively and their composition was represented by the same series of fatty acids (C13--C19). The qualitative composition and the quantitative content of fatty acids in phospholipids depended on the composition of the growth medium. When the actinomycetes were cultivated in a complex medium, the proportion between fatty acids (C14:0, C14:1, C16:0, C17:0, C17:1, C18:1, C18:2) changed. The qualitative composition of fatty acids in phospholipids varied among the cultures. However, the content of palmitoleic, palmitic and oleic acids was elevated in all of the cultures. Under the given experimental conditions, the actinomycetes were found to synthesize phospholipids containing fatty acids with a high degree of unsaturation (mainly at the account of C16:1 and C18:1 acids).

Chemical Phenomena↗

PubMed1977

[Study of natural mutiple drug resistance in actinomycetes of the genus Streptomyes].

Natural strains of actinomycetes belonging to 3 systematic groups of the Streptomyces genera, i.e. blue, gray and globisporine were characterized for their resistance to antibiotics and sulfamids. The majority of the strains were shown to have stable inherited multiple resistence to a wide variety of antibiotics. Linkage analysis for resistance determinants in pairs showed random distribution of most of the determinants among the members of the blue and grey groups of the actinomycetes. Non-random distribution of the resistance determinants to Tc, Cm and Rm in TcCm, TcRm conbinations for the blue group actinomycetes and to Om, Rm, Fa, Lm, Em, Rm and Tc in OmRm, FaLm, EmPm, TcOm combinations among the members of the grey group of actinomycetes was found.

Anti-Bacterial Agents↗