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Current Opinion in Microbiology Dec 2023Throughout the golden age of antibiotic discovery, Streptomyces have been unsurpassed for their ability to produce bioactive metabolites. Yet, this success has been... (Review)
Review
Throughout the golden age of antibiotic discovery, Streptomyces have been unsurpassed for their ability to produce bioactive metabolites. Yet, this success has been hampered by rediscovery. As we enter a new stage of biodiscovery, omics data and existing scientific repositories can enable informed choices on the biodiversity that may yield novel antibiotics. Here, we focus on the chemical potential of rare actinomycetes, defined as bacteria within the order Actinomycetales, but not belonging to the genus Streptomyces. They are named as such due to their less-frequent isolation under standard laboratory practices, yet there is increasing evidence to suggest these biologically diverse genera harbour considerable biosynthetic and chemical diversity. In this review, we focus on examples of successful isolation and genera that have been the focus of more concentrated biodiscovery efforts, we survey the representation of rare actinomycete taxa, compared with Streptomyces, across natural product data repositories in addition to its biosynthetic potential. This is followed by an overview of clinically useful drugs produced by rare actinomycetes and considerations for future biodiscovery efforts. There is much to learn about these underexplored taxa, and mounting evidence suggests that they are a fruitful avenue for the discovery of novel antimicrobials.
Topics: Actinobacteria; Actinomyces; Anti-Bacterial Agents; Streptomyces; Biodiversity
PubMed: 37804816
DOI: 10.1016/j.mib.2023.102385 -
Microbiology Spectrum Dec 2023As the management of wheat fungal diseases becomes increasingly challenging, the use of bacterial agents with biocontrol potential against the two major wheat...
As the management of wheat fungal diseases becomes increasingly challenging, the use of bacterial agents with biocontrol potential against the two major wheat phytopathogens, and , may prove to be an interesting alternative to conventional pest management. Here, we have shown that dimethylpolysulfide volatiles are ubiquitously and predominantly produced by wheat-associated and actinomycetes, displaying antifungal activity against both pathogens. By limiting pathogen growth and DON virulence factor production, the use of such DMPS-producing strains as soil biocontrol inoculants could limit the supply of pathogen inocula in soil and plant residues, providing an attractive alternative to dimethyldisulfide fumigant, which has many non-targeted toxicities. Notably, this study demonstrates the importance of bacterial volatile organic compound uptake by inhibited , providing new insights for the study of volatiles-mediated toxicity mechanisms within bacteria-fungus signaling crosstalk.
Topics: Arthrobacter; Microbacterium; Triticum; Actinobacteria; Actinomyces; Soil; Plant Diseases
PubMed: 37800942
DOI: 10.1128/spectrum.05292-22 -
PeerJ 2023The quest for microbial cellulases has intensified as a response to global challenges in biofuel production. The efficient deconstruction of lignocellulosic biomass...
The quest for microbial cellulases has intensified as a response to global challenges in biofuel production. The efficient deconstruction of lignocellulosic biomass holds promise for generating valuable products in various industries such as food, textile, and detergents. This article presents a systematic bioprospection aimed at isolating actinomycetes with exceptional cellulose deconstruction capabilities. Our methodology explored the biodiverse oligotrophic region of Cuatro Cienegas, Coahuila, within the Chihuahuan Desert. Among the evaluated actinomycetes collection, 78% exhibited cellulolytic activity. Through a meticulous screening process based on enzymatic index evaluation, we identified a highly cellulolytic strain for further investigation. Submerged fermentation of this strain revealed an endoglucanase enzymatic activity of 149 U/mg. Genomic analysis of strain sp. STCH565-A revealed unique configurations of carbohydrate-active enzyme (CAZyme) genes, underscoring its potential for lignocellulosic bioconversion applications. These findings not only highlight the significance of the Chihuahuan Desert as a rich source of cellulolytic microorganisms but also offer insights into the systematic exploration and selection of high-performing cellulolytic microorganisms for application in diverse environmental contexts. In conclusion, our bioprospecting study lays a foundation for harnessing the cellulolytic potential of actinomycetes from the Chihuahuan Desert, with implications for advancing cellulose deconstruction processes in various industries. The findings can serve as a blueprint for future bioprospecting efforts in different regions, facilitating the targeted discovery of microorganisms with exceptional cellulosic deconstruction capabilities.
Topics: Actinobacteria; Actinomyces; Cellulose; Cellulases; Cellulase; Streptomyces
PubMed: 37790635
DOI: 10.7717/peerj.16119 -
International Journal of Systematic and... Sep 2023Two novel Gram-positive bacteria designated as strains STR2 and STR3 were isolated from the rhizosphere of a sample collected from Goyang-si, Republic of Korea. Strains...
Two novel Gram-positive bacteria designated as strains STR2 and STR3 were isolated from the rhizosphere of a sample collected from Goyang-si, Republic of Korea. Strains STR2 and STR3 were aerobic, rod shaped, non-sporulated, catalase negative, oxidase negative and non-motile bacteria. They grew at 15-37 °C (optimum, 25-30 °C), at pH 6.0-11.0 (optimum, pH 7.0) and in the presence of 0-2% NaCl (optimum, 0 %, w/v). The chemotaxonomic and morphological characteristics of the novel strains were consistent with those of the members of . The phylogenetic analysis of the 16S rRNA gene sequences revealed that STR2 was closely related to YIM A1136 (99.3 %) and Y4 (99.1 %), and STR3 was closely related to DSM 22017 (99.0 %), G10 (98.8 %) and HFW-21 (98.7 %). The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values of STR2 and STR3 with the most closely related strains that have publicly available whole genomes were 83.1-89.8 %, 80.9-89.6% and 26.2-39.1 %, respectively. The cell-wall peptidoglycan of strain STR2 and STR3 contained ll-diaminopimelic acid as the diagnostic amino acid. The major fatty acids in STR2 and STR3 were iso-C and C ω8, and the predominant quinone was MK-8(H). Their polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and other polar lipids. The draft genome sequences showed that the genomic DNA G+C content of STR2 and STR3 were both 72.2 mol%. Physiological and biochemical tests and 16S rRNA sequence analysis clearly revealed that STR2 and STR3 could represent novel species. Their proposed names were as follows: sp. nov. for strain STR2 (=KACC 22784=TBRC 16336) and sp. nov. for strain STR3 (= KACC 22785=TBRC 16337).
Topics: Actinobacteria; Nocardioides; Actinomyces; Pinus; Phylogeny; RNA, Ribosomal, 16S; Base Composition; Fatty Acids; Sequence Analysis, DNA; DNA, Bacterial; Bacterial Typing Techniques; Amino Acids
PubMed: 37755157
DOI: 10.1099/ijsem.0.006062 -
BMJ Case Reports Sep 2023Actinomycosis is a rare chronic infection, caused by species of the bacterium spp. This report proposes oral breast trauma as a cause of infection. An adult female in...
Actinomycosis is a rare chronic infection, caused by species of the bacterium spp. This report proposes oral breast trauma as a cause of infection. An adult female in her 30s presented with a recurrent left breast abscess to a local hospital. She had previously undergone nine operations for abscess in the past 2 years. Shortly prior to her first presentation, a sexual partner with reported dental infection bit her periareolar area. The treating team noted that her bacterial culture from the first operation was positive for spp. She was treated with long-term intravenous antibiotics and had no further recurrences of infection. Oral trauma to the periareolar area by an individual with pre-existing dental disease has led to the introduction and establishment of this pathogen in the ductal system of the breast. This infection should be considered in cases of treatment resistant recurrent breast abscess.
Topics: Female; Adult; Humans; Abscess; Breast; Mastitis; Actinomycetaceae; Empyema, Pleural; Thoracic Injuries
PubMed: 37723094
DOI: 10.1136/bcr-2022-253472 -
Clinical Pediatrics Feb 2024
Topics: Humans; Empyema; Actinomycetaceae; Actinomycosis
PubMed: 37698129
DOI: 10.1177/00099228231200090 -
Scientific Reports Aug 2023Trueperella pecoris was described as a new species of the genus Trueperella in 2021 and might be pathogenic to various animal species. However, the lack of a suitable...
Trueperella pecoris was described as a new species of the genus Trueperella in 2021 and might be pathogenic to various animal species. However, the lack of a suitable diagnostic test system stands in the way of epidemiological surveys to clarify possible causalities. In this study, a Loop-mediated Isothermal Amplification (LAMP) assay was developed and validated that was highly specific for T. pecoris. The assay provided an analytical sensitivity of 0.5 pg/25 µL and showed 100% inclusivity and exclusivity for 11 target and 33 non-target strains, respectively. Three different DNA extraction methods were evaluated to select the most LAMP-compatible method for cell disruption in pure and complex samples. Using an on-site applicable single-buffer DNA extraction with additional heating, the cell-based detection limit was 2.3 CFU/reaction. Finally, the LAMP assay was validated by means of artificially contaminated porcine lung tissue samples in which minimal microbial loads between 6.54 and 8.37 × 10 CFU per swab sample were detectable. The LAMP assay established in this study represents a suitable diagnostic procedure for identifying T. pecoris in clinical specimens and will help to collect epidemiological data on the pathogenicity of this species.
Topics: Animals; Swine; Actinomycetaceae; Biological Assay; Cell Membrane; Heating
PubMed: 37635174
DOI: 10.1038/s41598-023-40787-1 -
The Lancet. Infectious Diseases Sep 2023
Topics: Humans; Actinomyces; Abdomen
PubMed: 37625860
DOI: 10.1016/S1473-3099(23)00182-2 -
Journal of Endodontics Nov 2023The extrusion of bacteria from infected root canals may lead to increase in symptoms, expansion of periapical lesions, and contribution to systemic diseases. The aim of...
INTRODUCTION
The extrusion of bacteria from infected root canals may lead to increase in symptoms, expansion of periapical lesions, and contribution to systemic diseases. The aim of this study is to investigate a potential proof-of-concept model to study the extent to which bacteria can escape from infected root canals under dynamic loading (simulated chewing).
METHODS
The study was completed in 2 experiments performed at 2 institutions. Biofilms of Streptococcus intermedius in the first experiment and S. intermedius and Actinomyces naeslundii were allowed to grow in root canals of single-rooted extracted teeth for 3 weeks. The roots of the teeth were suspended in a small chamber containing dental transport medium and were mounted on a lower sample holder of a chewing simulator. In the experimental group, simulated chewing cycles equivalent to 1 year of function were conducted, and then bacterial migration was quantified and compared with stationary teeth.
RESULTS
All experimental samples of the loading group revealed bacterial penetration in both experiments. Several of the unloaded samples revealed no bacterial penetration. In the first experiment, a significantly higher number of bacteria were able to escape into the periapex of the loaded group compared with the unloaded group (P = .017). In the second experiment, there was no significant difference between the 2 bacterial species used in the amount of extruded bacteria; however, there was a highly significant effect for occlusal loading (P = .0001).
CONCLUSIONS
The potential for occlusal forces to enhance bacterial extrusion from infected root canals should be further explored.
Topics: Dental Pulp Cavity; Humans; Mastication; Biofilms; Actinomyces; Streptococcus intermedius; In Vitro Techniques
PubMed: 37611655
DOI: 10.1016/j.joen.2023.08.008 -
Molecules (Basel, Switzerland) Aug 2023Actinomycetes inhabit both terrestrial and marine ecosystems and are highly proficient in producing a wide range of natural products with diverse biological functions,... (Review)
Review
Actinomycetes inhabit both terrestrial and marine ecosystems and are highly proficient in producing a wide range of natural products with diverse biological functions, including antitumor, immunosuppressive, antimicrobial, and antiviral activities. In this review, we delve into the life cycle, ecology, taxonomy, and classification of actinomycetes, as well as their varied bioactive metabolites recently discovered between 2015 and 2023. Additionally, we explore promising strategies to unveil and investigate new bioactive metabolites, encompassing genome mining, activation of silent genes through signal molecules, and co-cultivation approaches. By presenting this comprehensive and up-to-date review, we hope to offer a potential solution to uncover novel bioactive compounds with essential activities.
Topics: Actinobacteria; Actinomyces; Ecosystem; Anti-Infective Agents; Biological Products
PubMed: 37570885
DOI: 10.3390/molecules28155915