SEARCH · PubMed Health

Results for “ACTINOMYCETES”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 127 records · Page 7Linked to original sources

PubMed1983

Allergenic fungi and actinomycetes in smoking materials and their health implications.

Street marijuana, commercial cigarettes and pipe tobaccos were studied for the presence of fungi and actinomycetes associated with hypersensitivity pneumonitis. Aspergillus species and thermophilic actinomycetes were isolated from the smoking materials. In addition, Aspergillus fumigatus spores were isolated from marijuana smoke, indicating the potential hazard involved in developing serious disease. Precipitin antibodies against fungi, particularly Aspergillus, showed a higher prevalence in marijuana smokers, whereas only very few cigarette smokers and nonsmokers demonstrated antibodies to fungi. Cigarette smokers and nonsmokers showed more or less similar prevelance of antibodies against thermophilic actinomycetes.

Alveolitis, Extrinsic Allergic↗

PubMedDate not supplied

Suprageneric classification of peptidoglycan group B actinomycetes by nucleotide sequencing of 5S ribosomal RNA.

5S ribosomal RNA sequences were determined for thirteen actinomycetes mainly representatives with the rare group B type peptidoglycan. The primary and secondary structure of the resultant sequences were of the type characteristic of Gram-positive bacteria with DNA rich in guanine plus cytosine. The sequencing and associated chemotaxonomic data provide compelling grounds for classifying actinomycetes with a group B type peptidoglycan in a single family. The family Microbacteriaceae fam. nov. is proposed to accommodate actinomycetes classified in the genera Agromyces, Aureobacterium, Clavibacter, Curtobacterium and Microbacterium.

Actinomyces↗

PubMed1993

Mushroom worker's lung: serologic reactions to thermophilic actinomycetes present in the air of compost tunnels.

Vast numbers of spores of the thermophilic actinomycetes Excellospora flexuosa, Thermomonospora alba, T. curvata and T. fusca were collected from the air in fermentation tunnels during the spawning of mushroom compost, i.e. over 10(9) CFU m-3 of air. Five different genera of fungi, namely, Aspergillus, Aureobasidium, Cladosporium, Penicillium and Scytalidium, were found at only 10(3) CFU m-3 of air. Agaricus bisporus, used for spawning, was absent. Sera of 10 mushroom growers affected by Mushroom Worker's Lung (MWL) were tested by a qualitative dot-ELISA for antibodies against the spores of these micro-organisms. All 10 were positive for one or more of the actinomycetes E. flexuosa, T. alba, T. curvata and T. fusca. No antibodies were found against Streptomyces thermovulgaris, Thermoactinomyces vulgaris and T. sacchari nor against the fungi Aspergillus fumigatus, Penicillium brevicompactum, P. chrysogenum, Scytalidium thermophilum and Trichoderma viride. Sera of 11 of 14 workers engaged in routine spawning of compost in tunnels reacted positively with 1 or more of the actinomycetes. Their 10log serum titres increased with the duration of employment to an upper limit of 2.5. The sera of 19 non-exposed individuals were negative. Because high numbers of spores of E. flexuosa, T. alba, T. curvata and T. fusca were present in the air that was used for successful inhalation provocation of mushroom workers with MWL and because of the elevated serum titres of these workers, we presume these organisms to contribute in the occurrence of MWL.

Actinomycetales↗

PubMed2005

A novel actinomycete strain de-replication approach based on the diversity of polyketide synthase and nonribosomal peptide synthetase biosynthetic pathways.

The actinomycetes traditionally represent one of the most important sources for the discovery of new metabolites with biological activity; and many of these are described as being produced by polyketide synthases (PKS) and nonribosomal peptide synthetases (NRPS). We present a strain characterization system based on the metabolic potential of microbial strains by targeting these biosynthetic genes. After an initial evaluation of the existing bias derived from the PCR detection in a well defined biosynthetic systems, we developed a new fingerprinting approach based on the restriction analysis of these PKS and NRPS amplified sequences. This method was applied to study the distribution of PKS and NRPS biosynthetic systems in a collection of wild-type actinomycetes isolated from tropical soil samples that were evaluated for the production of antimicrobial activities. We discuss the application of this tool as an alternative characterization approach for actinomycetes and we comment on the relationship observed between the presence of PKS-I, PKS-II and NRPS sequences and the antimicrobial activities observed in some of the microbial groups tested.

Actinobacteria↗

PubMed2006

Targeting polyketide synthase gene pool within actinomycetes: new degenerate primers.

Natural products provide a unique element of molecular diversity and biological functionality and they are still indispensable for drug discovery. The polyketides, comprising a large and structurally diverse family of bioactive natural products, have been isolated from a group of mycelia-forming Gram-positive microorganisms, the actinomycetes. Relatively high amino acid sequence identity of the actinomycetes type I polyketide synthases (PKSs) was used to design three degenerate primer pairs for homology-based PCR detection of novel PKS genes, with particular interest into PKSs involved in biosynthesis of immunosuppressive-like metabolites. The stepdown PCR method, described here, enables fast insight into the PKS arsenal within actinomycetes. Designed primers and stepdown PCR were applied for the analysis of two natural isolates, Streptomyces sp. strains NP13 and MS405. Sequence analysis of chosen clones revealed the presence of two distinctive sequences in strain Streptomyces sp. NP13, but only one of these showed homology to PKS-related sequences. On analysing PCR amplicons derived from Streptomyces sp. strain MS405, three different PKS-related sequences were identified demonstrating a potential of designed primers to target PKS gene pool within single organism.

Actinobacteria↗

PubMed2005

Actinophages as indicators of actinomycete taxa in marine environments.

It is necessary to continue to screen for new metabolites and evaluate the potential of less known and new bacterial taxa so that new and improved compounds for future use against drug-resistant bacteria or for chemical modification may be developed. There has been considerable interest in the detection and identification of marine microorganisms since they have been reported to produce bioactive compounds ranging from antitumour to antibacterial and antiviral agents. In this study, an improved technique that involves the exploitation of marine actinophages as indicators of the marine actinomycete taxa and uses marine bacteriophages as tools to reduce the numbers of common marine bacteria, which impedes the growth of rare actinomycetes on isolation plates, has been applied. This technique reduced the numbers of colony forming units of unwanted bacteria on isolation plates and hence increased the chances of detecting novel marine actinomycete genera for isolation and subsequent screening for antiviral activity.

Actinobacteria↗

PubMed2005

Characterization of clinical isolates of pathogenic Nocardia strains and related actinomycetes in Thailand from 1996 to 2003.

In Thailand from 1996 to 2003, 171 strains of pathogenic aerobic actinomycetes from clinical specimens were isolated. Of those strains, 134 were mycolic acid containing actinomycetes, including 96 strains of Nocardia species. Others included 10 strains of Gordonia, 14 strains of Rhodococcus, and 22 strains of Mycobacterium. One strain each of the genera Tsukamurella and Corynebacterium were also isolated. Also identified were 27 strains of non-mycolic acid containing actinomycetes. Our identification studies of 96 strains of Nocardia species showed that significant pathogens in Thailand were N. beijingensis (18 strains), N. cyriacigeorgica (13 strains), and N. farcinica (34 strains); the most prevalent species was N. farcinica (35.4%). We also isolated four strains of N. asiatica, five strains of N. asteroides sensu stricto, four strains of N. nova, seven strains of N. otitidiscaviarum, eight strains of N. transvalensis, and two strains of N. pseudobrasiliensis.

Actinobacteria↗

PubMed1976

Immunologic cross-reactions among thermophilic actinomycetes associated with hypersensitivity pneumonitis.

Antibodies produced in rabbits against Micropolyspora faeni, Thermoactinomyces vulgaris, T. sacchari, Thermoactinomyces candidus, and Saccharomonospora viridis were tested against antigens derived from many strains of thermophilic actinomycetes for precipitating antibodies by immunodiffusion test. It was found that immune sera reacted strongly against antigens from strains belonging to the same species and weakly against antigens from different species of thermophilic actinomycetes. However, sera from farmer's lung patients showed cross-reactivity against antigens from different species. This may be because the patient is sensitized to multiple species of thermophilic actinomycetes present in the environment and developed antibodies against most of them.

Animals↗

PubMed1992

Early impressions concerning actinomycetal infections that may play a role in the pathogenesis of eosinophilia-myalgia syndrome (EMS) and other 'new illnesses'.

Actinomycetal infections by Actinomyces, Nocardia, and Streptomyces appear to be increasing in incidence. Clinical and laboratory data from twelve patients believed to have subclinical actinomycete-streptomycete infections (ASI)* are presented. It is proposed that the recent epidemic of eosinophilia-myalgia syndrome (EMS) may have been caused by pre-existing host ASI that generated toxic agents when individuals ingested supplemental L-tryptophan (LT). LT is the substrate used by streptomycetes to synthesize actinomycins, extremely cytotoxic metabolites that could have accounted for symptoms seen in EMS. Actinomycins inhibit CoA activity and interfere with the synthesis and utilization of amino acids. LT also provides streptomycetes with additional NAD, a substance of great importance to their DNA synthesis and metabolic activity. With increased activity, streptomycin, chloramphenicol, adriamycin or any one of the many secondary metabolites (antibiotics) produced by Streptomyces could be endogenously generated in greater quantities. The clinical result would be increased host toxicity. A contaminant that has been isolated from case associated lots of LT may have simply provided additional tryptophan for an ASI. It is also possible that a nucleotide or similar substance in the case associated LT products caused increased activation of tryptophan-2,3-dioxygenase, the rate-limiting enzyme required for the production of NAD and/or actinomycin. Potential reasons for ASI, atypical forms of actinomycete-streptomycete micro-organisms, and the possibility of involvement in other diseases are discussed.

Actinomyces↗

PubMed1992

Polyacrylamide gel electrophoresis analysis of ribosomal protein: a new approach for actinomycete taxonomy.

The ribosomal (r)-proteins from eleven Streptomyces strains representing various numerical taxonomic clusters were compared by two-dimensional polyacrylamide-gel electrophoresis (2D-PAGE). The protein patterns were specific for each species. An attempt was made to identify one strain of Streptomyces by both traditional taxonomic methods and 2D-PAGE analysis of the r-protein patterns. Both methods identified the strain as Streptomyces lavendulae, and protein pattern analysis also showed that S. griseolavendus was a variant of S. lavendulae. Actinomycete r-protein AT-L30 exhibited electrophoretic mobility that is specific for each genus. On the basis of this observation, we analyzed AT-L30 r-proteins from numerous strains of species belonging to the genera Actinomadura, Microtetraspora, Streptosporangium, Nocardia, Rhodococcus and mycolate-less wall chemotype-IV actinomycetes. The results strongly supported the conclusions of previous work and thus proved the efficacy of r-protein analysis as a novel approach for taxonomy of actinomycetes.

Actinomycetales↗

PubMed1993

Identification of some clinically significant actinomycetes.

Early recognition of infections caused by actinomycetes tend to be highly dependent on at least a tentative diagnosis derived from microbiological tests, since the clinical symptoms can be difficult to interpret. Reliable identification of clinically significant actinomycetes depends upon the application of taxonomic techniques that are not yet widely used in clinical laboratories. The value of rapid enzyme, chemical and molecular fingerprinting techniques is exemplified by their application to the identification of representatives of clinically significant actinomycete taxa.

Actinomycetales Infections↗

PubMed1993

Physiology of some actinomycete genera.

Actinomycetes are widespread in the environment and are mainly organotrophic. Studies of their ecology have been primarily focussed on their detection and isolation, with comparatively little attention to the control mechanisms that determine their occurrence and behaviour in their natural environments. This session provided some diverse examples of approaches to this problem. Several actinomycete genera produce motile spores. The significance of flagella proteins and factors influencing spore motility and germination are considered. The genus Frankia forms nitrogen-fixing associations with non-leguminous plants. Molecular techniques have been used to clarify the endophyte-host relationships. Micromonospora species are common in the environment. The growth and physiology of a gentamicin-producing strain are described. Thermophilic actinomycetes in the genus Thermoactinomyces are common in composts and other self-heating environments. Novel isolates from acid soil, which grow and produce enzymes active at high temperatures and in acidic conditions, are discussed.

Actinomycetales↗

PubMed2006

Chromium(VI) resistance and removal by actinomycete strains isolated from sediments.

Forty-one isolated actinomycetes were used to study qualitative and semi-quantitative screening of chromium(VI) resistance. Chromate-removing activity was estimated using the Cr(VI) specific colorimetric reagent 1,5-diphenylcarbazide. Twenty percent of the isolates from El Cadillal (EC) and 14% of isolates from a copper filter plant (CFP) were able to grow at 13 mM of Cr(VI). All isolates from sugar cane (SCP) could grow up to Cr(VI) concentration of 17 mM. EC, CFP and SCP strains were able to remove 24%, 30% and more than 40% of Cr(VI), respectively. The highest and lowest Cr(VI) specific removal values were 75.5 mg g(-1) cell by M3 (CFP), and 1.5 mg g(-1) cell by C35 (EC) strains. Eleven Cr(VI) resistant strains were characterized and identified as species of the genera Streptomyces (10) and Amycolatopsis (1). Differences on actinomycete community composition between contaminated and non-contaminated soil were found. This study showed the potential capacity of actinomycetes as tools for Cr(VI) bioremediation.

Actinobacteria↗

PubMed2005

Introduction of DNA into Actinomycetes by bacterial conjugation from E. coli--an evaluation of various transfer systems.

Gene transfer is a basic requirement for optimizing bioactive natural substances produced by an increasing number of industrially used microorganisms. We have analyzed quantitatively horizontal gene transfer from Escherichia coli to Actinomycetes. The efficiencies of DNA transfer of four different systems were compared that consist of conjugative and mobilizable plasmids with a broad-host range. Three novel binary vector set-ups were constructed based on: (i) the IncQ group of mobilizable plasmids (RSF1010), (ii) IncQ-like pTF-FC2 and (iii) pSB102 that belongs to a new class of broad-host-range plasmids. The established system based on the IncPalpha group of conjugative plasmids served as the reference. For all plasmids constructed, we confirmed the functional integrity of the selected transfer machineries by intrageneric matings between E. coli strains. We demonstrate that the transfer systems introduced in this study are efficient in mediating gene transfer from E. coli to Actinomycetes and are possible alternatives for gene transfer into Actinomycetes for which the IncPalpha-based transfer system is not applicable. The use of plasmids that integrate into the recipients' chromosomes compared to that of plasmids replicating autonomously is shown to allow the access to a wider range of hosts.

Actinobacteria↗

PubMed2024

Natural product discovery in soil actinomycetes: unlocking their potential within an ecological context.

Natural products (NPs) produced by bacteria, particularly soil actinomycetes, often possess diverse bioactivities and play a crucial role in human health, agriculture, and biotechnology. Soil actinomycete genomes contain a vast number of predicted biosynthetic gene clusters (BGCs) yet to be exploited. Understanding the factors governing NP production in an ecological context and activating cryptic and silent BGCs in soil actinomycetes will provide researchers with a wealth of molecules with potential novel applications. Here, we highlight recent advances in NP discovery strategies employing ecology-inspired approaches and discuss the importance of understanding the environmental signals responsible for activation of NP production, particularly in a soil microbial community context, as well as the challenges that remain.

Soil Microbiology↗

PubMed2006

Gas vesicles in actinomycetes?

Gas vesicles encoded by gvp genes provide buoyancy in many prokaryotes. In a recent Trends in Microbiology article entitled 'Gas vesicles in actinomycetes: old buoys in novel habitats?' van Keulen et al. documented the occurrence of gvp genes in soil-inhabiting actinomycetes but questioned whether any of them produce gas vesicles. We suggest that the protein encoded by gvpA in actinomycetes might be incompatible with the structure of the standard gas vesicle. Perhaps it has another role associated with the air-water interface.

Actinobacteria↗

PubMed2006

Actinomycetes in rice straw decomposition.

Actinomycetes are well known as lignocellulose decomposers. Forty-two cellulolytic actinomycete isolates have been recovered from soil. Those were identified to the genus level as: Streptomyces (26 isolates), Nocardiopsis (5 isolates), Micromonospora (4 isolates), Nocardioides (4 isolates) in addition to three isolates tentatively identified as Nocardia, Kibdelosporangium and Saccharomonospora. These actinomycetes were examined for their cellulolytic activity using filter paper strips and rice straw pieces. Four isolates of the four genera Kibdelosporangium, Micromonospora, Streptomyces and Nocardioides were able to efficiently degrade rice straw pieces in minimal medium causing significant weight loss between 50 and 61%. Application of this knowledge may improve the management of waste rice straw.

Actinobacteria↗

PubMedDate not supplied

Identification and evolution of the cellulolytic microflora present during composting of cattle manure: on the role of Actinomycetes sp.

Population changes in cellulolytic microflora were studied during composting of cattle manure. Six bacterial and nine actinomycetes species were isolated. Among the isolates, two actinomycetes, Micromonospora chalcae and Pseudonocardia thermophila, were cellulolytic strains which were numerically dominant and might therefore play a notable role in the degradation of cellulose in cattle manure. Fungi were practically absent during the process, but two cellulose-degrading bacterial species, Sporocytophaga myxococcoides and Cytophaga hutchinsonii, appeared to coexist in equilibrium with actinomycetes during the maturation phase.

Actinomycetales↗