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Pharmaceuticals (Basel, Switzerland) Jun 2024A tremendous increase in the green synthesis of metallic nanoparticles has been noticed in the last decades, which is due to their unique properties at the nano...
Exploring the Potential of Halotolerant Actinomycetes from Rann of Kutch, India: A Study on the Synthesis, Characterization, and Biomedical Applications of Silver Nanoparticles.
A tremendous increase in the green synthesis of metallic nanoparticles has been noticed in the last decades, which is due to their unique properties at the nano dimension. The present research work deals with synthesis mediated by the actinomycete of silver nanoparticles (AgNPs), isolated from Little and Greater Rann of Kutch, India. The confirmation of the formation of AgNPs by the actinomycetes was carried out by using a UV-Vis spectrophotometer where an absorbance peak was obtained at 420 nm. The X-ray diffraction pattern demonstrated five characteristic diffraction peaks indexed at the lattice plane (111), (200), (231), (222), and (220). Fourier transform infrared showed typical bands at 531 to 1635, 2111, and 3328 cm. Scanning electron microscopy shows that the spherical-shaped AgNPs particles have diameters in the range of 40 to 90 nm. The particle size analysis displayed the mean particle size of AgNPs in aqueous medium, which was about 55 nm (±27 nm), bearing a negative charge on their surfaces. The potential of the -mediated synthesized AgNPs was evaluated for their antimicrobial, anti-methicillin-resistant (MRSA), anti-biofilm, and anti-oxidant activity. The maximum inhibitory effect was observed against at (8 µg/mL), followed by and at (32 µg/mL), and against (64 µg/mL), whereas (128 µg/mL) and (256 µg/mL) were much less sensitive to AgNPs. The biosynthesized AgNPs displayed activity against MRSA, and the free radical scavenging activity was observed with an increase in the dosage of AgNPs from 25 to 200 µg/mL. AgNPs in combination with ampicillin displayed inhibition of the development of biofilm in and at 98% and 83%, respectively. AgNPs were also successfully coated on the surface of cotton to prepare antimicrobial surgical cotton, which demonstrated inhibitory action against (15 mm) and (12 mm). The present research integrates microbiology, nanotechnology, and biomedical science to formulate environmentally friendly antimicrobial materials using halotolerant actinomycetes, evolving green nanotechnology in the biomedical field. Moreover, this study broadens the understanding of halotolerant actinomycetes and their potential and opens possibilities for formulating new antimicrobial products and therapies.
PubMed: 38931410
DOI: 10.3390/ph17060743 -
Plants (Basel, Switzerland) Jun 2024The use of rhizospheric SynComs can be a new and sustainable strategy in the agrobiotechnology sector. The objective of this study was to create the most appropriate...
The use of rhizospheric SynComs can be a new and sustainable strategy in the agrobiotechnology sector. The objective of this study was to create the most appropriate SynCom composition; examine the ability to dissolve natural rock phosphate (RP) from Morocco in liquid-modified NBRIP medium; determine organic acids, and phytohormones; and verify plant growth promoting and nutrition uptake effect in the pot experiments of winter wheat (). A total of nine different microorganisms were isolated, which belonged to three different genera: , , and . Out of the 21 treatments tested, four SynComs had the best phosphate-dissolving properties: IJAK-27+44+91 (129.17 mg L), IIBEI-32+40 (90.95 µg mL), IIIDEG-45+41 (122.78 mg L), and IIIDEG-45+41+72 (120.78 mg L). We demonstrate that these SynComs are capable of producing lactic, acetic, gluconic, malic, oxalic, citric acids, and phytohormones such as indole-3-acetic acid, zeatin, gibberellic acid, and abscisic acid. In pot experiments with winter wheat, we also demonstrated that the designed SynComs were able to effectively colonize the plant root rhizosphere and contributed to more abundant plant growth characteristics and nutrient uptake as uninoculated treatment or uninoculated treatment with superphosphate (NPK 0-19-0). The obtained results show that the SynCom compositions of IJAK-27+44+91, IIBEI-32+40, IIIDEG-45+41, and IIIDEG-45+41+72 can be considered as promising candidates for developing biofertilizers to facilitate P absorption and increase plant nutrition.
PubMed: 38931148
DOI: 10.3390/plants13121716 -
Microorganisms Jun 2024Sigma factors are transcriptional regulators that are part of complex regulatory networks for major cellular processes, as well as for growth phase-dependent regulation...
Sigma factors are transcriptional regulators that are part of complex regulatory networks for major cellular processes, as well as for growth phase-dependent regulation and stress response. sp. SE50/110 is the natural producer of acarbose, an α-glucosidase inhibitor that is used in diabetes type 2 treatment. Acarbose biosynthesis is dependent on growth, making sigma factor engineering a promising tool for metabolic engineering. ACSP50_0507 is a homolog of the developmental and osmotic-stress-regulating σH. Therefore, the protein encoded by was named σH. Here, an sp. SE50/110 expression strain for the alternative sigma factor gene () achieved a two-fold increased acarbose yield with acarbose production extending into the stationary growth phase. Transcriptome sequencing revealed upregulation of acarbose biosynthesis genes during growth and at the late stationary growth phase. Genes that are transcriptionally activated by σH frequently code for secreted or membrane-associated proteins. This is also mirrored by the severely affected cell morphology, with hyperbranching, deformed and compartmentalized hyphae. The dehydrated cell morphology and upregulation of further genes point to a putative involvement in osmotic stress response, similar to its homolog. The DNA-binding motif of σH was determined based on transcriptome sequencing data and shows high motif similarity to that of its homolog. The motif was confirmed by in vitro binding of recombinantly expressed σH to the upstream sequence of a strongly upregulated gene. Autoregulation of σH was observed, and binding to its own gene promoter region was also confirmed.
PubMed: 38930623
DOI: 10.3390/microorganisms12061241 -
Microorganisms Jun 2024species are attractive sources of secondary metabolites that serve as major sources of antibiotics and other drugs. In this study, genome mining was used to determine...
species are attractive sources of secondary metabolites that serve as major sources of antibiotics and other drugs. In this study, genome mining was used to determine the biosynthetic potential of sp. 21So2-11 isolated from Antarctic soil. 16S rRNA gene sequencing revealed that this strain is most closely related to NBRC 101007, with a similarity of 98.02%. Genome comparisons based on average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) showed that strain 21So2-11 represents a novel species of the genus . In addition to a large number of genes related to environmental adaptation and ecological function, a total of 28 putative biosynthetic gene clusters (BGCs) responsible for the biosynthesis of known and/or novel secondary metabolites, including terpenes, lantipeptides, polyketides, nonribosomal peptides, RiPPs and siderophores, were detected in the genome of strain 21So2-11. In addition, a total of 1456 BGCs were predicted to contribute to the biosynthesis of more than 300 secondary metabolites based on the genomes of 47 strains originating from polar regions. The results indicate the potential of sp. 21So2-11 for bioactive secondary metabolite production and are helpful for understanding bacterial adaptability and ecological function in cold terrestrial environments.
PubMed: 38930610
DOI: 10.3390/microorganisms12061228 -
Microorganisms May 2024is an emerging human pathogen that has a high rate of incidence in immunocompromised individuals. We have found a putative secondary metabolite pathway within , which...
is an emerging human pathogen that has a high rate of incidence in immunocompromised individuals. We have found a putative secondary metabolite pathway within , which may be a key factor in its pathogenesis. This novel pathway is encoded in a gene cluster spanning MAB_0284c to 0305 and is related to pathways, producing the secondary metabolites streptonigrin and nybomycin. We constructed an in-frame deletion of the MAB_0295 () gene and tested it in our animal model. We have previously shown that tadpoles, which have functional lungs and T cells, can serve as a reliable comparative model for persistent infection and pathogenesis. Here, we report that tadpoles intraperitoneally infected with the ∆ mutant exhibit early decreased bacterial loads and significantly increased survival compared with those infected with WT . ∆ mutant also induced lower transcript levels of several pro-inflammatory cytokines (, , , ) than those of WT in the liver and lungs. In addition, there was impaired macrophage recruitment and decreased macrophage infection in tadpoles infected with the ∆ mutant, by tail wound inoculation, compared to those infected with the WT bacteria, as assayed by intravital confocal microscopy. These data underline the relevance and usefulness of tadpoles as a novel comparative animal model to identify genetic determinants of immunopathogenesis, suggesting a role for this novel and uncharacterized pathway in pathogenesis and macrophage recruitment.
PubMed: 38930501
DOI: 10.3390/microorganisms12061120 -
Biology May 2024This work aimed to study the genome organization and the metabolic potential of strain SCPM-O-B-9993, a promising plant-protecting and plant-stimulating strain isolated...
This work aimed to study the genome organization and the metabolic potential of strain SCPM-O-B-9993, a promising plant-protecting and plant-stimulating strain isolated from brown semi-desert soils with very high salinity. The strain genome contains a linear chromosome 5,968,715 bp long and has no plasmids. The genome contains 5331 coding sequences among which 2139 (40.1%) are functionally annotated. Biosynthetic gene clusters (BGCs) of secondary metabolites exhibiting antimicrobial properties (ohmyungsamycin, pellasoren, naringenin, and ansamycin) were identified in the genome. The most efficient period of SCPM-O-B-9993 strain cultivation was 72 h: during this period, the culture went from the exponential to the stationary growth phase as well as exhibited excellent phytostimulatory properties and antiviral activity against the cucumber mosaic virus in tomatoes under laboratory conditions. The SCPM-OB-9993 strain is a biotechnologically promising producer of secondary metabolites exhibiting antiviral and phytostimulatory properties.
PubMed: 38927268
DOI: 10.3390/biology13060388 -
Toxins May 2024Zearalenone (ZEN) is a prevalent mycotoxin found in grains and grain-derived products, inducing adverse health effects in both animals and humans. The in-field...
Zearalenone (ZEN) is a prevalent mycotoxin found in grains and grain-derived products, inducing adverse health effects in both animals and humans. The in-field application of microorganisms to degrade and detoxify ZEN is a promising strategy to enhance the safety of food and feed. In this study, we investigated the potential of three actinobacterial strains to degrade and detoxify ZEN in vitro and in planta on wheat ears. The residual ZEN concentration and toxicity in the samples were analysed with UHPLC-MS/MS and a bioluminescence BLYES assay, respectively. subsp. LMG19352 could completely degrade and detoxify 5 mg/L ZEN in LB broth within 24 h, along with significant reductions in ZEN concentration both in a minimal medium (MM) and on wheat ears. Additionally, it was the only strain that showed a significant colonisation of these ears. sp. R25614 exhibited partial but significant degradation in LB broth and MM, whereas sp. LMG16995 degraded and detoxified ZEN in LB broth after 72 h by 39% and 33%, respectively. Although all three actinobacterial strains demonstrated the metabolic capability to degrade and detoxify ZEN in vitro, only subsp. LMG19352 showed promising potential to mitigate ZEN in planta. This distinction underscores the importance of incorporating in planta screening assays for assessing the potential of mycotoxin-biotransforming microorganisms as biocontrol agents.
Topics: Zearalenone; Triticum; Biological Control Agents; Streptomyces; Actinobacteria; Food Contamination; Tandem Mass Spectrometry
PubMed: 38922147
DOI: 10.3390/toxins16060253 -
Marine Drugs Jun 2024Three new cyclic lipopeptides, olenamidonins A-C (-), in addition to two previously reported metabolites ( and ), were accumulated in the Δ deletion mutant of...
Three new cyclic lipopeptides, olenamidonins A-C (-), in addition to two previously reported metabolites ( and ), were accumulated in the Δ deletion mutant of deepsea-derived SCSIO 1071. The structures of these cyclic lipopeptides were determined by a combination of spectroscopic methods and circular dichroism (CD) measurement. The antibacterial assay results showed that compounds displayed different degrees of growth inhibition against multidrug-resistant (MDR) bacterial strains CCARM 5172 and CCARM 5203 with minimum inhibitory concentrations (MICs) of 1.56-6.25 μg/mL.
Topics: Streptomyces; Lipopeptides; Microbial Sensitivity Tests; Anti-Bacterial Agents; Enterococcus faecalis; Peptides, Cyclic; Enterococcus faecium; Drug Resistance, Multiple, Bacterial; Bacterial Proteins
PubMed: 38921573
DOI: 10.3390/md22060262 -
Marine Drugs Jun 2024A new dimeric C-glycoside polyketide chrysomycin F (), along with four new monomeric compounds, chrysomycins G (), H (), I (), J (), as well as three known analogues,...
A new dimeric C-glycoside polyketide chrysomycin F (), along with four new monomeric compounds, chrysomycins G (), H (), I (), J (), as well as three known analogues, chrysomycins A (), B (), and C (), were isolated and characterised from a strain of sp. obtained from a sediment sample collected from the South China Sea. Their structures were determined by detailed spectroscopic analysis. Chrysomycin F contains two diastereomers, whose structures were further elucidated by a biomimetic [2 + 2] photodimerisation of chrysomycin A. Chrysomycins B and C showed potent anti-tuberculosis activity against both wild-type and a number of clinically isolated MDR strains.
Topics: Streptomyces; Mycobacterium tuberculosis; Antitubercular Agents; Polyketides; Microbial Sensitivity Tests; Glycosides; China; Molecular Structure; Anthraquinones
PubMed: 38921570
DOI: 10.3390/md22060259 -
Marine Drugs May 2024Subjecting the Australian marine-derived fungus CMB-M0339 to cultivation profiling using an innovative miniaturized 24-well plate format (MATRIX) enabled access to new...
Subjecting the Australian marine-derived fungus CMB-M0339 to cultivation profiling using an innovative miniaturized 24-well plate format (MATRIX) enabled access to new examples of the rare class of 2,6-diketopiperazines, noonazines A-C (-), along with the known analogue coelomycin (), as well as a new azaphilone, noonaphilone A (). Structures were assigned to - on the basis of a detailed spectroscopic analysis, and in the case of -, an X-ray crystallographic analysis. Plausible biosynthetic pathways are proposed for -, involving oxidative Schiff base coupling/dimerization of a putative Phe precursor. Of note, incorporates a rare -Tyr motif, typically only reported in a limited array of metabolites. Similarly, a plausible biosynthetic pathway is proposed for , highlighting a single point for stereo-divergence that allows for the biosynthesis of alternate antipodes, for example, the 7 noonaphilone A () versus the 7 deflectin 1a ().
Topics: Aspergillus; Australia; Diketopiperazines; Aquatic Organisms; Biosynthetic Pathways; Crystallography, X-Ray; Molecular Structure; Benzopyrans; Pigments, Biological
PubMed: 38921553
DOI: 10.3390/md22060243