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Acta Tropica Jan 2022Mycetoma is a chronic granulomatous inflammatory disease that is caused either by bacteria or fungi. Bacterial mycetoma (actinomycetoma) can be caused by various... (Review)
Review
Mycetoma is a chronic granulomatous inflammatory disease that is caused either by bacteria or fungi. Bacterial mycetoma (actinomycetoma) can be caused by various causative agents of the genera Nocardia, Streptomyces and Actinomadura. On the other hand, fungal mycetoma (eumycetoma) is most commonly caused by causative agents belonging to the genera Madurella, Scedosporium and Falciformispora. Early and accurate diagnosis of the causative organisms can guide proper patient management and treatment. To allow rapid and accurate species identification, different molecular techniques were developed over the past decades. These techniques can be protein based (MALDI-TOF MS) as well as DNA based (Sequencing, PCR and isothermal amplification methods). In this review, we provide an overview of the different molecular techniques currently in use and identify knowledge gaps, which need to be addressed before we can implement molecular diagnostics for mycetoma in different clinical settings.
Topics: Fungi; Humans; Madurella; Mycetoma; Polymerase Chain Reaction; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 34687643
DOI: 10.1016/j.actatropica.2021.106205 -
International Journal of Systematic and... Oct 2020The taxonomic positions of two novel aerobic, Gram-positive actinobacteria, designated strains RB29 and RB68, were determined using a polyphasic approach. Based on 16S...
The taxonomic positions of two novel aerobic, Gram-positive actinobacteria, designated strains RB29 and RB68, were determined using a polyphasic approach. Based on 16S rRNA gene sequence analysis, the closest phylogenetic neighbours of RB29 were identified as DSM 102126 (99.2 % similarity) and DSM 43919 (98.7 %), and for strain RB68 was DSM 44148 (98.3 %). Digital DNA-DNA hybridization (dDDH) between RB29 and its closest phylogenetic neighbours, DSM 102126 and DSM 43919, resulted in similarity values of 53.2 % (50.6-55.9 %) and 26.4 % (24.1-28.9 %), respectively. Additionally, the average nucleotide identity (ANI) was 93.2 % (94.0 %) for DSM 102126 and 82.3 % (78.9 %) for DSM 43919. dDDH analysis between strain RB68 and DSM 44148 gave a similarity value of 24.5 % (22.2-27.0 %). Both strains, RB29 and RB68, revealed morphological characteristics and chemotaxonomic features typical for the genus , such as the presence of -diaminopimelic acid in the cell wall, galactose and glucose as major sugar components within whole-cell hydrolysates and the absence of mycolic acids. The major phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. Predominant menaquinones were MK-9(H) and MK-9(H) for RB29 and MK-9(H) and MK-9(H) for RB68. The main fatty acids were identified as 10-methyloctadecanoic acid (10-methyl C), 14-methylpentadecanoic acid (iso-C), hexadecanoic acid (C) and -9-octadecanoic acid (C ω9). Here, we propose two novel species of the genus : sp. nov. with the type strain RB29 (=CCUG 72668=NRRL B-65537) and sp. nov. with the type strain RB68 (=CCUG 72669=NRRL B-65538).
Topics: Actinobacteria; Animals; Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Diaminopimelic Acid; Fatty Acids; Gastrointestinal Microbiome; Isoptera; Nucleic Acid Hybridization; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; South Africa; Vitamin K 2
PubMed: 32845828
DOI: 10.1099/ijsem.0.004403 -
RSC Advances Jul 2019Actinomycetes are outstanding and fascinating sources of potent bioactive compounds, particularly antibiotics. In recent years, rare actinomycetes have had an... (Review)
Review
Actinomycetes are outstanding and fascinating sources of potent bioactive compounds, particularly antibiotics. In recent years, rare actinomycetes have had an increasingly important position in the discovery of antibacterial compounds, especially , and . Focusing on the period from 2008 to 2018, we herein summarize the structures and bioactivities of secondary metabolites from rare actinomycetes, involving 21 genera.
PubMed: 35518871
DOI: 10.1039/c9ra03579f -
Frontiers in Microbiology 2015The lack of new antibiotics in the pharmaceutical pipeline guides more and more researchers to leave the classical isolation procedures and to look in special niches and... (Review)
Review
The lack of new antibiotics in the pharmaceutical pipeline guides more and more researchers to leave the classical isolation procedures and to look in special niches and ecosystems. Bioprospecting of extremophilic Actinobacteria through mining untapped strains and avoiding resiolation of known biomolecules is among the most promising strategies for this purpose. With this approach, members of acidtolerant, alkalitolerant, psychrotolerant, thermotolerant, halotolerant and xerotolerant Actinobacteria have been obtained from respective habitats. Among these, little survey exists on the diversity of Actinobacteria in arid areas, which are often adapted to relatively high temperatures, salt concentrations, and radiation. Therefore, arid and desert habitats are special ecosystems which can be recruited for the isolation of uncommon Actinobacteria with new metabolic capability. At the time of this writing, members of Streptomyces, Micromonospora, Saccharothrix, Streptosporangium, Cellulomonas, Amycolatopsis, Geodermatophilus, Lechevalieria, Nocardia, and Actinomadura are reported from arid habitats. However, metagenomic data present dominant members of the communities in desiccating condition of areas with limited water availability that are not yet isolated. Furthermore, significant diverse types of polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes are detected in xerophilic and xerotolerant Actinobacteria and some bioactive compounds are reported from them. Rather than pharmaceutically active metabolites, molecules with protection activity against drying such as Ectoin and Hydroxyectoin with potential application in industry and agriculture have also been identified from xerophilic Actinobacteria. In addition, numerous biologically active small molecules are expected to be discovered from arid adapted Actinobacteria in the future. In the current survey, the diversity and biotechnological potential of Actinobacteria obtained from arid ecosystems, along with the recent work trend on Iranian arid soils, are reported.
PubMed: 26858692
DOI: 10.3389/fmicb.2015.01541 -
Frontiers in Pharmacology 2022Colorectal cancer (CRC) is a common, and deadly disease. Despite the improved knowledge on CRC heterogeneity and advances in the medical sciences, there is still an... (Review)
Review
Colorectal cancer (CRC) is a common, and deadly disease. Despite the improved knowledge on CRC heterogeneity and advances in the medical sciences, there is still an urgent need to cope with the challenges and side effects of common treatments for the disease. Natural products (NPs) have always been of interest for the development of new medicines. Actinobacteria are known to be prolific producers of a wide range of bioactive NPs, and scientific evidence highlights their important protective role against CRC. This review is a holistic picture on actinobacter-derived cytotoxic compounds against CRC that provides a good perspective for drug development and design in near future. This review also describes the chemical structure of 232 NPs presenting anti-CRC activity with the being majority of quinones, lactones, alkaloids, peptides, and glycosides. The study reveals that most of these NPs are derived from marine actinobacteria followed by terrestrial and endophytic actinobacteria, respectively. They are predominantly produced by , , and , respectively, in which as the predominant contributor generating over 76% of compounds exclusively. Besides it provides a valuable snapshot of the chemical structure-activity relationship of compounds, highlighting the presence or absence of some specific atoms and chemical units in the structure of compounds can greatly influence their biological activities. To the best of our knowledge, this is the first comprehensive review on natural actinobacterial compounds affecting different types of CRC. Our study reveals that the high diversity of actinobacterial strains and their NPs derivatives, described here provides a new perspective and direction for the production of new anti-CRC drugs and paves the way to innovation for drugs discovery in the future. The knowledge obtain from this review can help us to understand the pivotal application of actinobacteria in future drugs development.
PubMed: 35899111
DOI: 10.3389/fphar.2022.929161 -
Indian Journal of Dermatology,... 2022Background Mycetoma is widespread in Yemen; however, there are only a few documented reports on the entity from this geographical area. Methods A prospective study of...
Background Mycetoma is widespread in Yemen; however, there are only a few documented reports on the entity from this geographical area. Methods A prospective study of 184 cases of mycetoma (male 145 and female 39) from different regions of north-western Yemen was conducted between July 2000 and May 2014. Clinical profile was recorded in a standardized protocol. The diagnosis was based on clinical features, X-ray studies, examination of grains, and histopathology. Results Eumycetoma was diagnosed in 129, caused by Madurella mycetomatis in 124, Leptosphaeria senegalensis in one and pale grain fungus in four, whereas actinomycetoma occurred in 55, caused by Streptomyces somaliensis in 29, Actinomadura madurai in nine, Actinomadura pelletieri in one, and Nocardia in sixteen. Eumycetoma cases were treated with prolonged course of antifungal drugs, mostly ketoconazole, with itraconazole being used in four patients, along with excision or debulking. Results were better when antifungal drugs were given two to three months before surgery and in those who received itraconazole. Actinomycetoma cases were initially treated with co-trimoxazole monotherapy; later streptomycin was added in 30 cases. Six patients who did not show adequate improvement and two others from the start were treated with modified Welsh regimen and with good results. Limitations Identification of different causative agents was done by histopathology and could not be reconfirmed by culture. Conclusion Mycetoma is widespread in north-western Yemen with a higher incidence of eumycetoma and a majority of the cases were caused by Madurella mycetomatis. Modified Welsh regimen in actinomycetoma and itraconazole with excision in eumycetoma showed the best results.
Topics: Antifungal Agents; Female; Humans; India; Itraconazole; Madurella; Male; Mycetoma; Prospective Studies; Yemen
PubMed: 35389029
DOI: 10.25259/IJDVL_500_2021 -
Molecules (Basel, Switzerland) Nov 2022Large scale cultivation and chemical investigation of an extract obtained from sp. resulted in the identification of six previously undescribed spirotetronates...
Large scale cultivation and chemical investigation of an extract obtained from sp. resulted in the identification of six previously undescribed spirotetronates (pyrrolosporin B and decatromicins C-G; -), along with six known congeners, namely decatromicins A-B (-), BE-45722B-D (-), and pyrrolosporin A (). The chemical structures of compounds - were characterized via comparison with previously reported data and analysis of 1D/2D NMR and MS data. The structures of all new compounds were highly related to the spirotetronate type compounds, decatromicin and pyrrolosporin, with variations in the substituents on the pyrrole and aglycone moieties. All compounds were evaluated for antibacterial activity against the Gram-negative bacteria, and Gram-positive bacteria, and were investigated for their cytotoxicity against the human cancer cell line A549. Of these, decatromicin B (), BE-45722B (), and pyrrolosporin B () exhibited potent antibacterial activities against both Gram-positive (MIC between 1-3 μM) and Gram-negative bacteria (MIC values ranging from 12-36 μM) with weak or no cytotoxic activity against A549 cells.
Topics: Humans; Polyketides; Actinomadura; Anti-Bacterial Agents; Gram-Negative Bacteria; Gram-Positive Bacteria; Microbial Sensitivity Tests
PubMed: 36500287
DOI: 10.3390/molecules27238196 -
Natural Product Reports Mar 2024Covering: up to the end of 2022In recent years rare Actinobacteria have become increasingly recognised as a rich source of novel bioactive metabolites. are... (Review)
Review
Covering: up to the end of 2022In recent years rare Actinobacteria have become increasingly recognised as a rich source of novel bioactive metabolites. are Gram-positive bacteria that occupy a wide range of ecological niches. This review highlights about 230 secondary metabolites produced by spp., reported until the end of 2022, including their bioactivities and selected biosynthetic pathways. Notably, the bioactive compounds produced by spp. demonstrate a wide range of activities, including antimicrobial, antitumor and anticoccidial effects, highlighting their potential in various fields.
Topics: Actinomadura; Actinobacteria; Anti-Infective Agents; Bacteria; Biology
PubMed: 38099919
DOI: 10.1039/d3np00047h -
Frontiers in Microbiology 2021, an important Chinese medicinal herb, can be mainly cultivated in two planting patterns, cropland planting (DT) and understory planting (LX). We speculate that the...
, an important Chinese medicinal herb, can be mainly cultivated in two planting patterns, cropland planting (DT) and understory planting (LX). We speculate that the rhizosphere microbiome may vary in DT and LX and may play an important role in promoting the growth and health of . In the present study, culture-independent Illumina HiSeq was employed to investigate the rhizosphere bacteria and fungi under DT and LX planting patterns. Predominant phyla include , , , , and in the two planting patterns. DT has higher alpha diversity index than LX. The predominant LX-core genera include , , and the predominant DT-core genera include , , and . Total relative abundance of the disease-suppression phylum (, , and ) and the potential plant growth-promoting rhizobacteria (PGPR) were both significantly higher in LX than in DT. We also identified over-presented microbial functional traits mediating plant-microbe and microbe-microbe interactions, nutrition acquisition, and plant growth promotion in rhizosphere. Our findings provide a valuable reference for studying beneficial microbes and pathogens of planted in DT and LX.
PubMed: 34177857
DOI: 10.3389/fmicb.2021.673512 -
Applied and Environmental Microbiology May 2022Nonheme iron- and α-ketoglutarate (αKG)-dependent halogenases (NHFeHals), which catalyze the regio- and stereoselective halogenation of the unactivated C()-H bonds,...
Nonheme iron- and α-ketoglutarate (αKG)-dependent halogenases (NHFeHals), which catalyze the regio- and stereoselective halogenation of the unactivated C()-H bonds, exhibit tremendous potential in the challenging asymmetric halogenation. AdeV from Actinomadura sp. ATCC 39365 is the first identified carrier protein-free NHFeHal that catalyzes the chlorination of nucleotide 2'-deoxyadenosine-5'-monophosphate (2'-dAMP) to afford 2'-chloro-2'-deoxyadenosine-5'-monophosphate. Here, we determined the complex crystal structures of AdeV/Fe/Cl and AdeV/Fe/Cl/αKG at resolutions of 1.76 and 1.74 Å, respectively. AdeV possesses a typical β-sandwich topology with H194, H252, αKG, chloride, and one water molecule coordinating Fe in the active site. Molecular docking, mutagenesis, and biochemical analyses reveal that the hydrophobic interactions and hydrogen bond network between the substrate-binding pocket and the adenine, deoxyribose, and phosphate moieties of 2'-dAMP are essential for substrate recognition. Residues H111, R177, and H192 might play important roles in the second-sphere interactions that control reaction partitioning. This study provides valuable insights into the catalytic selectivity of AdeV and will facilitate the rational engineering of AdeV and other NHFeHals for synthesis of halogenated nucleotides. Halogenated nucleotides are a group of important antibiotics and are clinically used as antiviral and anticancer drugs. AdeV is the first carrier protein-independent nonheme iron- and α-ketoglutarate (αKG)-dependent halogenase (NHFeHal) that can selectively halogenate nucleotides and exhibits restricted substrate specificity toward several 2'-dAMP analogues. Here, we determined the complex crystal structures of AdeV/Fe/Cl and AdeV/Fe/Cl/αKG. Molecular docking, mutagenesis, and biochemical analyses provide important insights into the catalytic selectivity of AdeV. This study will facilitate the rational engineering of AdeV and other carrier protein-independent NHFeHals for synthesis of halogenated nucleotides.
Topics: Carrier Proteins; Ferrous Compounds; Halogenation; Halogens; Iron; Ketoglutaric Acids; Molecular Docking Simulation; Nucleotides
PubMed: 35435717
DOI: 10.1128/aem.02497-21