Streptomyces are of great interest in the pharmaceutical industry as they produce a plethora of secondary metabolites that act as antibacterial and antifungal agents. They may thrive on their own in the soil, or associate with other organisms, such as plants or invertebrates. Some soil-derived strains exhibit hemolytic properties when cultivated on blood agar, raising the question of whether hemolysis could be a virulence factor of the bacteria. In this work we examined hemolytic compound production in 23 β-hemolytic Streptomyces isolates; of these 12 were soil-derived, 10 were arthropod-associated, and 1 was plant-associated. An additional human-associated S. sp. TR1341 served as a control. Mass spectrometry analysis suggested synthesis of polyene molecules responsible for the hemolysis: candicidins, filipins, strevertene A, tetrafungin, and tetrin A, as well as four novel polyene compounds (denoted here as polyene A, B, C, and D) in individual liquid cultures or paired co-cultures. The non-polyene antifungal compounds actiphenol and surugamide A were also identified. The findings indicate that the ability of Streptomyces to produce cytolytic compounds (here manifested by hemolysis on blood agar) is an intrinsic feature of the bacteria in the soil environment and could even serve as a virulence factor when colonizing available host organisms. Additionally, a literature review of polyenes and non-polyene hemolytic metabolites produced by Streptomyces is presented.
Regulatory RNAs control a number of physiological processes in bacterial cells. Here we report on a 6S-like RNA transcript (scr3559) that affects both development and antibiotic production in Streptomyces coelicolor. Its expression is enhanced during the transition to stationary phase. Strains that over-expressed the scr3559 gene region exhibited a shortened exponential growth phase in comparison with a control strain; accelerated aerial mycelium formation and spore maturation; alongside an elevated production of actinorhodin and undecylprodigiosin. These observations were supported by LC-MS analyses of other produced metabolites, including: germicidins, desferrioxamines, and coelimycin. A subsequent microarray differential analysis revealed increased expression of genes associated with the described morphological and physiological changes. Structural and functional similarities between the scr3559 transcript and 6S RNA, and its possible employment in regulating secondary metabolite production are discussed.
- Publikační typ
- časopisecké články MeSH
Mandibular/alveolar (m/a) bone, as a component of the periodontal apparatus, allows for the proper tooth anchorage and function of dentition. Bone formation around the tooth germs starts prenatally and, in the mouse model, the mesenchymal condensation turns into a complex vascularized bone (containing osteo-blasts, -cytes, -clasts) within only two days. This very short but critical period is characterized by synchronized cellular and molecular events. The m/a bone, as others, is subjected to endocrine regulations. This not only requires vasculature to allow the circulation of active molecules (ligands), but also the expression of corresponding cell receptors to define target tissues. This contribution aimed at following the dynamics of calciotropic receptors ́ expression during morphological transformation of a mesenchymal condensation into the initial m/a bone structure. Receptors for all three calciotropic systemic regulators: parathormone, calcitonin and activated vitamin D (calcitriol), were localized on serial histological sections using immunochemistry and their relative expression was quantified by q-PCR. The onset of calciotropic receptors was followed along with bone cell differentiation (as checked using osteocalcin, sclerostin, RANK and TRAP) and vascularization (CD31) during mouse prenatal/embryonic (E) days 13-15 and 18. Additionally, the timing of calciotropic receptor appearance was compared with that of estrogen receptors (ESR1, ESR2). PTH receptor (PTH1r) appeared in the bone already at E13, when the first osteocalcin-positive cells were detected within the mesenchymal condensation forming the bone anlage. At this stage, blood vessels were only lining the condensation. At E14, the osteoblasts started to express the receptor for activated vitamin D (VDR). At this stage, the vasculature just penetrated the forming bone. On the same day, the first TRAP-positive (but not yet multinucleated) osteoclastic cells were identified. However, calcitonin receptor was detected only one day later. The first Sost-positive osteocytes, present at E15, were PTH1r and VDR positive. ESR1 almost copied the expression pattern of PTH1r, and ESR2 appearance was similar with VDR with a significant increase between E15 and E18. This report focuses on the in vivo situation and links morphological transformation of the mesenchymal cell condensation into a bone structure with dynamics of cell differentiation/maturation, vascularization and onset of receptors for calciotropic endocrine signalling in developing m/a bone.
- MeSH
- adaptorové proteiny signální transdukční analýza genetika MeSH
- buněčná diferenciace MeSH
- imunohistochemie MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- mandibula růst a vývoj MeSH
- messenger RNA analýza MeSH
- myši MeSH
- osteoblasty fyziologie MeSH
- osteocyty fyziologie MeSH
- osteogeneze fyziologie MeSH
- osteokalcin analýza genetika MeSH
- osteoklasty fyziologie MeSH
- receptory kalcitoninu metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Tuftelin was originally discovered and mostly studied in the tooth, but later found also in other organs. Despite its wide distribution among tissues, tuftelin's function has so far been specified only in the formation of enamel crystals. Nevertheless, in many cases, tuftelin was suggested to be associated with cellular adaptation to hypoxia and recently even with cell differentiation. Therefore, we aimed to investigate tuftelin expression along with hypoxia-inducible factors (HIFs) during the early development of the mandibular/alveolar (m/a) bone, when osteoblasts started to differentiate in vivo and to compare their expression levels in undifferentiated versus differentiated osteoblastic cells in vitro. Immunohistochemistry demonstrated the presence of tuftelin already in osteoblastic precursors which were also HIF1-positive, but HIF2-negative. Nevertheless, HIF2 protein appeared when osteoblasts differentiated, one day later. This is in agreement with observations made with MC3T3-E1 cells, where there was no significant difference in tuftelin and Hif1 expression in undifferentiated vs. differentiated cells, although Hif2 increased upon differentiation induction. In differentiated osteoblasts of the m/a bone, all three proteins accumulated, first, prenatally, in the cytoplasm and later, particularly at postnatal stages, they displayed also peri/nuclear localization. Such a dynamic time-space pattern of tuftelin expression has recently been reported in neurons, which, as the m/a bone, differentiate under less hypoxic conditions as indicated also by a prevalent cytoplasmic expression of HIF1 in osteoblasts. However, unlike what was shown in cultured neurons, tuftelin does not seem to participate in final osteoblastic differentiation and its functions, thus, appears to be tissue specific.
- MeSH
- buňky 3T3 MeSH
- faktor 1 indukovatelný hypoxií analýza genetika MeSH
- imunohistochemie MeSH
- kultivované buňky MeSH
- myši MeSH
- osteogeneze genetika MeSH
- proteiny zubní skloviny analýza genetika MeSH
- transkripční faktory analýza genetika MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The complex development undergone by Streptomyces encompasses transitions from vegetative mycelial forms to reproductive aerial hyphae that differentiate into chains of single-celled spores. Whereas their mycelial life - connected with spore formation and antibiotic production - is deeply investigated, spore germination as the counterpoint in their life cycle has received much less attention. Still, germination represents a system of transformation from metabolic zero point to a new living lap. There are several aspects of germination that may attract our attention: (1) Dormant spores are strikingly well-prepared for the future metabolic restart; they possess stable transcriptome, hydrolytic enzymes, chaperones, and other required macromolecules stabilized in a trehalose milieu; (2) Germination itself is a specific sequence of events leading to a complete morphological remodeling that include spore swelling, cell wall reconstruction, and eventually germ tube emergences; (3) Still not fully unveiled are the strategies that enable the process, including a single cell's signal transduction and gene expression control, as well as intercellular communication and the probability of germination across the whole population. This review summarizes our current knowledge about the germination process in Streptomyces, while focusing on the aforementioned points.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND: Bacterial spore germination is a developmental process during which all required metabolic pathways are restored to transfer cells from their dormant state into vegetative growth. Streptomyces are soil dwelling filamentous bacteria with complex life cycle, studied mostly for they ability to synthesize secondary metabolites including antibiotics. RESULTS: Here, we present a systematic approach that analyzes gene expression data obtained from 13 time points taken over 5.5 h of Streptomyces germination. Genes whose expression was significantly enhanced/diminished during the time-course were identified, and classified to metabolic and regulatory pathways. The classification into metabolic pathways revealed timing of the activation of specific pathways during the course of germination. The analysis also identified remarkable changes in the expression of specific sigma factors over the course of germination. Based on our knowledge of the targets of these factors, we speculate on their possible roles during germination. Among the factors whose expression was enhanced during the initial part of germination, SigE is though to manage cell wall reconstruction, SigR controls protein re-aggregation, and others (SigH, SigB, SigI, SigJ) control osmotic and oxidative stress responses. CONCLUSIONS: From the results, we conclude that most of the metabolic pathway mRNAs required for the initial phases of germination were synthesized during the sporulation process and stably conserved in the spore. After rehydration in growth medium, the stored mRNAs are being degraded and resynthesized during first hour. From the analysis of sigma factors we conclude that conditions favoring germination evoke stress-like cell responses.
- MeSH
- echokardiografie MeSH
- infarkt myokardu komplikace MeSH
- koronární aneurysma MeSH
- lidé MeSH
- ruptura diagnóza farmakoterapie chirurgie MeSH
- senioři MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
