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Scientific Reports Feb 2022The capture and safe storage of radioactive iodine (I or I) are of a compelling significance in the generation of nuclear energy and waste storage. Because of their...
The capture and safe storage of radioactive iodine (I or I) are of a compelling significance in the generation of nuclear energy and waste storage. Because of their physiochemical properties, Porous Organic Polymers (POPs) are considered to be one of the most sought classes of materials for iodine capture and storage. Herein, we report on the preparation and characterization of two triazine-based, nitrogen-rich, porous organic polymers, NRPOP-1 (SA = 519 m g) and NRPOP-2 (SA = 456 m g), by reacting 1,3,5-triazine-2,4,6-triamine or 1,4-bis-(2,4-diamino-1,3,5-triazine)-benzene with thieno[2,3-b]thiophene-2,5-dicarboxaldehyde, respectively, and their use in the capture of volatile iodine. NRPOP-1 and NRPOP-2 showed a high adsorption capacity of iodine vapor with an uptake of up to 317 wt % at 80 °C and 1 bar and adequate recyclability. The NRPOPs were also capable of removing up to 87% of iodine from 300 mg L iodine-cyclohexane solution. Furthermore, the iodine-loaded polymers, I@NRPOP-1 and I@NRPOP-2, displayed good antibacterial activity against Micrococcus luteus (ML), Escherichia coli (EC), and Pseudomonas aeruginosa (PSA). The synergic functionality of these novel polymers makes them promising materials to the environment and public health.
Topics: Adsorption; Anti-Bacterial Agents; Drug Resistance, Bacterial; Drug Storage; Escherichia coli; Iodine Radioisotopes; Micrococcus luteus; Nitrogen; Organic Chemicals; Polymers; Porosity; Triazines; Volatilization
PubMed: 35173259
DOI: 10.1038/s41598-022-06671-0 -
Developmental and Comparative Immunology Aug 2021The formation of extracellular traps (ETs) is an important innate immune mechanism that serves to combat different invading pathogens. In this study, zymosan...
The formation of extracellular traps (ETs) is an important innate immune mechanism that serves to combat different invading pathogens. In this study, zymosan significantly induced the formation of ETs in the hemocytes of Ruditapes philippinarum, and this effect was accompanied by translocation of the mitochondria to the cell surface. Zymosan stimulation clearly induced an increase in intracellular ROS and MPO production and an overexpression of ROS-related genes (PI3K, AKT and HIF). In response to the ROS burst, the mitochondrial membrane potential decreased, and the mitochondrial permeability transition pore opened. Conversely, mitochondrial superoxide inhibitor (Mito-TEMPO) significantly inhibited the formation of ETs, suggesting that mitochondrial ROS were necessary for the formation of ETs. In addition, we found that zymosan-induced ETs showed antibacterial activities against gram-negative and gram-positive bacteria, such as Vibrio anguillarum, Vibrio harveyi, Escherichia coli and Micrococcus luteus. Taken together, these findings elucidated a new antibacterial approach for R. philippinarum and highlighted the role of mitochondria in the formation of zymosan-induced ETs.
Topics: Animals; Bivalvia; Escherichia coli; Extracellular Traps; Hemocytes; Micrococcus luteus; Mitochondria; Vibrio; Zymosan
PubMed: 33823212
DOI: 10.1016/j.dci.2021.104094 -
International Journal of Biological... Dec 2016Bio-composites films were prepared by casting and drying of aqueous solutions containing different weight ratios of chitosan and bark of Mimosa tenuiflora. The...
Bio-composites films were prepared by casting and drying of aqueous solutions containing different weight ratios of chitosan and bark of Mimosa tenuiflora. The physico-chemical and functional properties of the films were characterized by scanning electron microscopy, dynamical mechanical analysis, wettability, cytotoxicity and in vitro antibacterial activities. The morphology studies confirmed that the presence of Mimosa tenuiflora change the surface of films. Moreover, the incorporation of Mimosa tenuiflora improved the thermal stability of the films, as it was indicated by the changes in the glass temperatures obtained. Water-uptake ability changed in relation to polymeric composition of film. This property increased by the addition of Mimosa tenuiflora to the film. Improved antibacterial properties were measured against Escherichia Coli and Micrococcus lysodeikticus or luteus. Finally, cytotoxicity was studied by MTT assay and the films were non-toxic. These preliminary results provide a cheap way to prepare chitosan/Mimosa tenuiflora films for wound healing and skin regeneration.
Topics: 3T3 Cells; Animals; Anti-Bacterial Agents; Bandages; Biocompatible Materials; Chitosan; Escherichia coli; Mice; Micrococcus; Mimosa; Regeneration; Skin; Transdermal Patch; Wettability
PubMed: 27693339
DOI: 10.1016/j.ijbiomac.2016.09.083 -
Protoplasma Sep 2022The interaction of plant roots with bacteria is influenced by chemical signaling, where auxins play a critical role. Auxins exert positive or negative influences on the...
The interaction of plant roots with bacteria is influenced by chemical signaling, where auxins play a critical role. Auxins exert positive or negative influences on the plant traits responsible of root architecture configuration such as root elongation and branching and root hair formation, but how bacteria that modify the plant auxin response promote or repress growth, as well as root structure, remains unknown. Here, we isolated and identified via molecular and electronic microscopy analysis a Micrococcus luteus LS570 strain as a plant growth promoter that halts primary root elongation in Arabidopsis seedlings and strongly triggers root branching and absorptive potential. The root biomass was exacerbated following root contact with bacterial streaks, and this correlated with inducible expression of auxin-related gene markers DR5:GUS and DR5:GFP. Cellular and structural analyses of root growth zones indicated that the bacterium inhibits both cell division and elongation within primary root tips, disrupting apical dominance, and as a consequence differentiation programs at the pericycle and epidermis, respectively, triggers the formation of longer and denser lateral roots and root hairs. Using Arabidopsis mutants defective on auxin signaling elements, our study uncovers a critical role of the auxin response factors ARF7 and ARF19, and canonical auxin receptors in mediating both the primary root and lateral root response to M. luteus LS570. Our report provides very basic information into how actinobacteria interact with plants and direct evidence that the bacterial genus Micrococcus influences the cellular and physiological plant programs ultimately responsible of biomass partitioning.
Topics: Arabidopsis; Arabidopsis Proteins; Gene Expression Regulation, Plant; Indoleacetic Acids; Micrococcus luteus; Plant Roots
PubMed: 34792622
DOI: 10.1007/s00709-021-01724-z -
ACS Applied Materials & Interfaces Aug 2022Protective equipment for detecting bacterial contamination has been in high demand with increasing interest in public health and hygiene. Herein, a fiber-based visually...
Protective equipment for detecting bacterial contamination has been in high demand with increasing interest in public health and hygiene. Herein, a fiber-based visually indicating bacteria sensor (VIBS) embedded with iodonitrotetrazolium chloride is developed for the general purpose of detecting live bacteria, and its chromogenic effectiveness is investigated for Gram-negative and Gram-positive . The developed color intensity is measured by the light absorption coefficient to the scattering coefficient (/) based on the Kubelka-Munk equation, and the colorimetric sensitivities of different membranes are examined by calculating the limit of detection (LOD) and the limit of quantification (LOQ). The results demonstrate that the interactions between VIBS and bacteria depend on the wetting properties of membranes. A hydrophobic membrane shows excessive interactions at high concentrations of Gram-negative bacteria, whose cell membrane is lipophilic. The membrane blended with hydrophobic and hydrophilic polymers displays linear colorimetric responses for both Gram-negative and Gram-positive bacteria strains, demonstrating a reliable sensing capability in the range of the tested bacteria concentration. This study is significant in that explorative experimentations are performed to conceive a proof of concept of a fiber-based bacteria sensor, which is readily applicable in various fields where bacteria pose a threat.
Topics: Bacteria; Colorimetry; Escherichia coli; Gram-Negative Bacteria; Gram-Positive Bacteria; Micrococcus luteus
PubMed: 35946791
DOI: 10.1021/acsami.2c08613 -
Applied Microbiology and Biotechnology Mar 2020Multiple heavy metal-resistant bacterium, Micrococcus luteus strain AS2, was isolated from industrial waste water of District Sheikhupura, Pakistan. The isolated...
Phenotypic and genomic analysis of multiple heavy metal-resistant Micrococcus luteus strain AS2 isolated from industrial waste water and its potential use in arsenic bioremediation.
Multiple heavy metal-resistant bacterium, Micrococcus luteus strain AS2, was isolated from industrial waste water of District Sheikhupura, Pakistan. The isolated bacterium showed minimum inhibitory concentrations of 55 and 275 mM against arsenite and arsenate. The bacterial strain also showed resistance against other heavy metal ions, i.e., lead, cadmium, chromium, mercury, nickel, and zinc, apart from arsenic. The optimum temperature and pH were 37 °C and 7, respectively. The antioxidant enzymes such as catalase were significantly increased under arsenite stress. The increase in 43.9% of GSH/GSSG and 72.72% of non-protein thiol was determined under15 mM arsenite stress. Bacterial genome was sequenced through Illumina and Nanopore and genes related to arsenic and other heavy metals were identified and blast (tblastx) on NCBI. Through scanning electron microscopy, no morphological changes were observed in bacterial cells under arsenite stress. The peaks appeared in EDX showed that there is surface adsorption of arsenite in bacterial cell while it was confirmed from Fourier transformed infrared spectroscopy analysis that there is some interaction between arsenite and functional groups present on the surface of bacterial cell. The SDS-PAGE analysis of whole-cell proteins under 15 mM arsenite stress clearly revealed that there is upregulation of some proteins in ranged of 60 to 34 kDa. The bioremediation efficiency (E) of bacterial biomass was 72% after 2 h and 99% after 10 h. The bioremediation efficiency of bacterial biomass is an indicator for the isolated bacterium to employ as a potential candidate for the amelioration of sites contaminated with arsenic.
Topics: Arsenic; Biodegradation, Environmental; Cadmium; Chromium; Industrial Waste; Micrococcus luteus; Wastewater
PubMed: 31927763
DOI: 10.1007/s00253-020-10351-2 -
Environmental Science and Pollution... Aug 2022Levofloxacin (LFX) is a widely used antibiotic medication. Persistent traces of LFX in water and wastewater may induce bacterial resistance. Photon-driven advanced... (Comparative Study)
Comparative Study
Levofloxacin (LFX) is a widely used antibiotic medication. Persistent traces of LFX in water and wastewater may induce bacterial resistance. Photon-driven advanced oxidation processes (AOPs) can assist in attaining complete abatement of LFX for environmental protection. This work benchmarks different solar AOPs based on hydroxyl radical (OH) and sulphate radical (SO) chemistry. Other oxidant precursors, as radical sources, were used to selectively control the generation of either hydroxyl radical (i.e., HO), sulphate radical (i.e., peroxydisulphate (PDS)), or a controlled mixture ratio of both OH/SO (i.e., peroxymonosulphate (PMS)). The influence of pH on degradation performance was evaluated using unbuffered and buffered solutions. Simulated irradiation/PMS process exhibited a strong pH-dependence attaining partial degradation of ca. 56% at pH 5 up to complete degradation at pH 7. Despite the similitudes on the abatement of target pollutant LFX in pristine solutions, only simulated irradiation/PDS treatment achieved effective abatement of LFX in wastewater samples given the higher selectivity of SO. Toxicity tests were conducted with Escherichia coli (LMG2092) and Micrococcus flavus (DSM1790), demonstrating successful inhibition of the antibiotic character of polluted waters, which would contribute to preventing the development of resistant bacterial strains. Finally, a degradative pathway was suggested from the by-products and intermediates identified by LC-MS. Results demonstrate that the degradation of specific functional groups (i.e., piperazine ring) is associated with the loss of antibacterial character of the molecule.
Topics: Anti-Bacterial Agents; Escherichia coli; Hydrogen Peroxide; Hydroxyl Radical; Kinetics; Levofloxacin; Micrococcus; Oxidation-Reduction; Sunlight; Wastewater; Water Pollutants, Chemical
PubMed: 35359212
DOI: 10.1007/s11356-022-19768-w -
Nature Communications Aug 2020Here, we demonstrate the self-assembly of the antimicrobial human LL-37 active core (residues 17-29) into a protein fibril of densely packed helices. The surface of the...
Here, we demonstrate the self-assembly of the antimicrobial human LL-37 active core (residues 17-29) into a protein fibril of densely packed helices. The surface of the fibril encompasses alternating hydrophobic and positively charged zigzagged belts, which likely underlie interactions with and subsequent disruption of negatively charged lipid bilayers, such as bacterial membranes. LL-37 correspondingly forms wide, ribbon-like, thermostable fibrils in solution, which co-localize with bacterial cells. Structure-guided mutagenesis analyses supports the role of self-assembly in antibacterial activity. LL-37 resembles, in sequence and in the ability to form amphipathic helical fibrils, the bacterial cytotoxic PSMα3 peptide that assembles into cross-α amyloid fibrils. This argues helical, self-assembling, basic building blocks across kingdoms of life and points to potential structural mimicry mechanisms. The findings expose a protein fibril which performs a biological activity, and offer a scaffold for functional and durable biomaterials for a wide range of medical and technological applications.
Topics: Amyloid; Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Bacteria; Benzothiazoles; Cathelicidins; Crystallography, X-Ray; Gorilla gorilla; Humans; Microbial Sensitivity Tests; Micrococcus luteus; Microscopy, Confocal; Microscopy, Electron, Transmission; Models, Molecular; Protein Conformation; Staphylococcus hominis; X-Ray Diffraction
PubMed: 32753597
DOI: 10.1038/s41467-020-17736-x -
Chinese Journal of Natural Medicines Jun 2019Three new phenazine-type compounds, named phenazines SA-SC (1-3), together with four new natural products (4-7), were isolated from the fermentation broth of an...
Three new phenazine-type compounds, named phenazines SA-SC (1-3), together with four new natural products (4-7), were isolated from the fermentation broth of an earwig-associated Streptomyces sp. NA04227. The structures of these compounds were determined by extensive analyses of NMR, high resolution mass spectroscopic data, as well as single-crystal X-ray diffraction measurement. Sequencing and analysis of the genome data allowed us to identify the gene cluster (spz) and propose a biosynthetic pathway for these phenazine-type compounds. Additionally, compounds 1-5 exhibited moderate inhibitory activity against acetylcholinesterase (AChE), and compound 3 showed antimicrobial activities against Micrococcus luteus.
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Crystallography, X-Ray; Insecta; Magnetic Resonance Spectroscopy; Microbial Sensitivity Tests; Micrococcus luteus; Molecular Structure; Multigene Family; Phenazines; Streptomyces
PubMed: 31262460
DOI: 10.1016/S1875-5364(19)30055-X -
Journal, Genetic Engineering &... Dec 2023Lipases have emerged as essential biocatalysts, having the ability to contribute to a wide range of industrial applications. Microbial lipases have garnered significant...
BACKGROUND
Lipases have emerged as essential biocatalysts, having the ability to contribute to a wide range of industrial applications. Microbial lipases have garnered significant industrial attention due to their stability, selectivity, and broad substrate specificity. In the previous study, a unique lipolytic bacterium (Micrococcus luteus EMP48-D) was isolated from tempeh. It turns out the bacteria produce an acidic lipase, which is important in biodiesel production. Our main objectives were to clone the acidic lipase and investigate its potential in biodiesel production.
RESULT
In this study, the gene encoding a lipase from M. luteus EMP48-D was cloned and expressed heterologously in Escherichia coli. To our knowledge, this is the first attempt at the cloning and expression of the lipase gene from Micrococcus luteus. The amino acid sequence was deduced from the nucleotide sequence (1356 bp) corresponded to a protein of 451 amino acid residues with a molecular weight of about 40 kDa. The presence of a signal peptide suggested that the protein was extracellular. A sequence analysis revealed that the protein had a lipase-specific Gly-X-Ser-X-Gly motif. The enzyme was identified as an acidic lipase with a pH preference of 5.0. Fatty acid preferences for enzyme activities were C8 and C12 (p-nitrophenyl esters), with optimum temperatures at 30-40 °C and still remaining active at 80°C. The enzyme was also shown to convert up to 70% of the substrate into fatty acid methyl ester.
CONCLUSION
The enzyme was a novel acidic lipase that demonstrated both hydrolytic and transesterification reactions. It appeared particularly promising for the synthesis of biodiesel as this enzyme's catalytic reaction was optimum at low temperatures and was still active at high temperatures.
PubMed: 38038870
DOI: 10.1186/s43141-023-00611-9