Disease relevance of Actinobacteria

• Another interesting result of analysis of operon structures and BirA sites is that some biotin-dependent carboxylases from Rhodobacter capsulatus, actinomycetes, and archaea are possibly coregulated with BirA [1].
• Cystathionine gamma-lyase (EC 4.4.1.1) is widely distributed in actinomycetes, e.g. genera Streptomyces, Micromonospora, Micropolyspora, Mycobacterium, Nocardia, Streptosporangium, and Streptoverticillium [2].
• At the amino acid level, the cmr gene is 52% identical to a previously identified chloramphenicol-resistance determinant in Streptomyces lividans, indicating a wider dispersion of this type of cmr gene among the actinomycetes [3].
• The ornithine carbamoyltransferases (OTCases) from the beta-lactam-producing actinomycetes Streptomyces clavuligerus and Nocardia lactamdurans have been purified to near-homogeneity by delta-N-phosphonoacetylornithine-Sepharose 4B affinity chromatography [4].
• Ciclopirox olamine is a substituted pyridone antimycotic, unrelated to the imidazole derivatives, with activity against a broad spectrum of dermatophytes, yeasts, actinomycetes, molds, other fungi, and a variety of Gram-positive and Gram-negative bacteria [5].

High impact information on Actinobacteria

• Leupeptin, isolated from Actinomycetes, is a potent and specific inhibitor of proteases [6].
• The antibiotic bleomycin, a strong DNA cutting agent, is naturally produced by actinomycetes which have developed a resistance mechanism against such a lethal compound [7].
• A balanced synthesis of beta-lactam antibiotics, beta-lactamase and PBP is postulated to be critical for the survival of beta-lactam-producing actinomycetes [8].
• The highly aerobic actinomycetes produce mycothiol, a conjugate of N-acetylcysteine with a pseudodisaccharide of glucosamine and myo-inositol, AcCys-GlcNalpha(1 --> 1)Ins, which appears to play an antioxidant role similar to glutathione [9].
• Ergothioneine, also produced by actinomycetes, remains a mystery despite many years of study [9].

Chemical compound and disease context of Actinobacteria

• Mycothiol (MSH; 1-D-myo-inosityl-2-(N-acetyl-L-cysteinyl)amido-2-deoxy-alpha-D- glucop yranoside (AcCys-GlcN-Ins)) is a novel thiol produced at millimolar levels by mycobacteria and other actinomycetes that do not make glutathione [10].
• Pepstatin A, a natural pentapeptide isolated from cultures of actinomycetes, induced histamine secretion from human basophils in the concentration range of 3 X 10(-7) to 10(-4) M [11].
• Because restoration of pimaricin production in the npi287 mutant is conferred by both A-factor and PI factor, S. natalensis appears to be able to integrate different quorum signals from actinomycetes [12].
• In conclusion, GlcP, which is the first glucose permease from high G+C Gram-positive bacteria characterized at the molecular level, represents the major glucose uptake system in S. coelicolor A3(2) that is indispensable for the high growth rate on glucose [13].
• Severely scorbutic guinea pig leukocytes killed only 12% of phagocytosed actinomycetes, had distorted nuclear morphology, had 16 times less ascorbate, and had no chemotactic responses in vitro [14].

Biological context of Actinobacteria

• Tropheryma whipplei Twist: a human pathogenic Actinobacteria with a reduced genome [15].
• The predicted amino acid sequence of the garA gene, including both the N-terminal phosphorylation motif and the FHA domain, is strongly conserved in mycobacteria and other related actinomycetes, suggesting a functional role of GarA in putative STPK-mediated signal transduction pathways [16].
• A Sorangium cellulosum (myxobacterium) gene cluster for the biosynthesis of the macrolide antibiotic soraphen A: cloning, characterization, and homology to polyketide synthase genes from actinomycetes [17].
• DNA sequences which hybridized strongly with the lat gene of N. lactamdurans were found in four cephamycin-producing Streptomyces species but not in four other actinomycetes which are not known to produce beta-lactams, suggesting that the gene is specific for beta-lactam biosynthesis and is not involved in general lysine catabolism [18].
• Analysis of completed bacterial genomes indicates that the convergent beta-ketoadipate pathway and some aspects of its genetic organization are characteristic of rhodococci and related actinomycetes [19].

Anatomical context of Actinobacteria

• A fermentation product of the soil actinomycetes Streptomyces nodosus, amphotericin B binds selectively to ergosterol in the cell membrane of susceptible fungi, inducing changes in permeability that can produce lethal cell injury [20].
• Elastatinal, a specific inhibitor of elastases, isolated from actinomycetes (Streptomyces griseoruber), forms stable complexes with elastase from human (Ki = 6.2 X 10(-6)M) and canine granulocytes (Ki = 1.1 X 10(-6)M) [21].

Gene context of Actinobacteria

• The parC gene was detected in actinobacteria for the first time [22].
• (type strain VKM Ac-1804T=UCM Ac-620T) is proposed to accommodate aerobic, oxidase- and catalase-positive, weakly motile, coryneform actinobacteria isolated from leaf galls induced by the plant-parasitic nematode Heteroanguina graminophila in narrow reed grass, Calamagrostis neglecta [23].
• Both the ClgR- and sigmaH-dependent regulation of clpC and clpP1P2 expression appears to be conserved in other actinomycetes [24].
• The pks12 gene (Maa1979), which may be cotranscribed with a downstream gene (Maa1980), is widely conserved in the actinomycetes [25].
• Finally, T-boxes likely involved in the regulation of translation initiation were observed upstream of ileS genes from several Actinobacteria [26].

Analytical, diagnostic and therapeutic context of Actinobacteria

• Deletion mapping and sequence analysis showed that the RT activity of Streptomcyces TopA resides in a peptide region containing motifs that are absent from most bacterial topoisomerases but are highly conserved in a novel subfamily of eubacterial topoisomerases found largely in Actinobacteria [27].
• Southern blot hybridization analysis revealed that this type of dioxygenase gene is distributed among diverse dibenzofuran-utilizing actinomycetes [28].
• An HPLC procedure which separates D- and L-amino acid isomers was applied to an analysis of peptidoglycan of 2,4-diaminobutyric acid (DAB)-containing actinomycetes [29].
• In 350 pancervico-vaginal (Fast) smears obtained from women using intrauterine contraceptive devices, organisms consistent with Actinomycetes have been found [30].

References