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Trends in Microbiology Nov 2020
Topics: Bacterial Proteins; Ferrosoferric Oxide; Iron; Magnetosomes; Magnetospirillum
PubMed: 32674989
DOI: 10.1016/j.tim.2020.06.001 -
Biotechnology Advances 2023Different from other aerobic microorganisms that oxidise carbon sources to water and carbon dioxide, Gluconobacter catalyses the incomplete oxidation of various... (Review)
Review
Different from other aerobic microorganisms that oxidise carbon sources to water and carbon dioxide, Gluconobacter catalyses the incomplete oxidation of various substrates with regio- and stereoselectivity. This ability, as well as its capacity to release the resulting products into the reaction media, place Gluconobacter as a privileged member of a non-model microorganism class that may boost industrial biotechnology. Knowledge of new technologies applied to Gluconobacter has been piling up in recent years. Advancements in its genetic modification, application of immobilisation tools and careful designs of the transformations, have improved productivities and stabilities of Gluconobacter strains or enabled new bioconversions for the production of valuable marketable chemicals. In this work, the latest advancements applied to Gluconobacter-catalysed biotransformations are summarised with a special focus on recent available tools to improve them. From genetic and metabolic engineering to bioreactor design, the most recent works on the topic are analysed in depth to provide a comprehensive resource not only for scientists and technologists working on/with Gluconobacter, but for the general biotechnologist.
Topics: Gluconobacter; Gluconobacter oxydans; Biotechnology; Catalysis; Biotransformation
PubMed: 36924811
DOI: 10.1016/j.biotechadv.2023.108127 -
Nature Communications Sep 2019Spin wave logic circuits using quantum oscillations of spins (magnons) as carriers of information have been proposed for next generation computing with reduced energy...
Spin wave logic circuits using quantum oscillations of spins (magnons) as carriers of information have been proposed for next generation computing with reduced energy demands and the benefit of easy parallelization. Current realizations of magnonic devices have micrometer sized patterns. Here we demonstrate the feasibility of biogenic nanoparticle chains as the first step to truly nanoscale magnonics at room temperature. Our measurements on magnetosome chains (ca 12 magnetite crystals with 35 nm particle size each), combined with micromagnetic simulations, show that the topology of the magnon bands, namely anisotropy, band deformation, and band gaps are determined by local arrangement and orientation of particles, which in turn depends on the genotype of the bacteria. Our biomagnonic approach offers the exciting prospect of genetically engineering magnonic quantum states in nanoconfined geometries. By connecting mutants of magnetotactic bacteria with different arrangements of magnetite crystals, novel architectures for magnonic computing may be (self-) assembled.
Topics: Anisotropy; Computer Simulation; Crystallization; Genotype; Magnetics; Magnetosomes; Magnetospirillum; Mutation; Nanoparticles; Particle Size; Quantum Theory; Spin Labels
PubMed: 31554798
DOI: 10.1038/s41467-019-12219-0 -
Microbiological Research Oct 2017Bacterial magnetosome, synthetized by magnetosome-producing microorganisms including magnetotactic bacteria (MTB) and some non-magnetotactic bacteria (Non-MTB), is a new... (Review)
Review
Bacterial magnetosome, synthetized by magnetosome-producing microorganisms including magnetotactic bacteria (MTB) and some non-magnetotactic bacteria (Non-MTB), is a new type of material comprising magnetic nanocrystals surrounded by a phospholipid bilayer. Because of the special properties such as single magnetic domain, excellent biocompatibility and surface modification, bacterial magnetosome has become an increasingly attractive for researchers in biology, medicine, paleomagnetism, geology and environmental science. This review briefly describes the general feature of magnetosome-producing microorganisms. This article also highlights recent advances in the understanding of the biochemical and magnetic characteristics of bacterial magnetosome, as well as the magnetosome formation mechanism including iron ions uptake, magnetosome membrane formation, biomineralization and magnetosome chain assembly. Finally, this review presents the potential applications of bacterial magnetosome in biomedicine, wastewater treatment, and the significance of mineralization of magnetosome in biology and geology.
Topics: Cell Membrane; Ferrosoferric Oxide; Iron; Magnetic Fields; Magnetosomes; Magnetospirillum; Sulfides
PubMed: 28754204
DOI: 10.1016/j.micres.2017.06.005 -
Marine Drugs Jan 2015Magnetotactic bacteria (MTB) produce intracellular organelles called magnetosomes which are magnetic nanoparticles composed of magnetite (Fe3O4) or greigite (Fe3S4)... (Review)
Review
Magnetotactic bacteria (MTB) produce intracellular organelles called magnetosomes which are magnetic nanoparticles composed of magnetite (Fe3O4) or greigite (Fe3S4) enveloped by a lipid bilayer. The synthesis of a magnetosome is through a genetically controlled process in which the bacterium has control over the composition, direction of crystal growth, and the size and shape of the mineral crystal. As a result of this control, magnetosomes have narrow and uniform size ranges, relatively specific magnetic and crystalline properties, and an enveloping biological membrane. These features are not observed in magnetic particles produced abiotically and thus magnetosomes are of great interest in biotechnology. Most currently described MTB have been isolated from saline or brackish environments and the availability of their genomes has contributed to a better understanding and culturing of these fastidious microorganisms. Moreover, genome sequences have allowed researchers to study genes related to magnetosome production for the synthesis of magnetic particles for use in future commercial and medical applications. Here, we review the current information on the biology of MTB and apply, for the first time, a genome mining strategy on these microorganisms to search for secondary metabolite synthesis genes. More specifically, we discovered that the genome of the cultured MTB Magnetovibrio blakemorei, among other MTB, contains several metabolic pathways for the synthesis of secondary metabolites and other compounds, thereby raising the possibility of the co-production of new bioactive molecules along with magnetosomes by this species.
Topics: Biological Products; Magnetic Phenomena; Magnetosomes; Rhodospirillaceae
PubMed: 25603340
DOI: 10.3390/md13010389 -
Nature Reviews. Microbiology Sep 2016Magnetotactic bacteria derive their magnetic orientation from magnetosomes, which are unique organelles that contain nanometre-sized crystals of magnetic iron minerals.... (Review)
Review
Magnetotactic bacteria derive their magnetic orientation from magnetosomes, which are unique organelles that contain nanometre-sized crystals of magnetic iron minerals. Although these organelles have evident potential for exciting biotechnological applications, a lack of genetically tractable magnetotactic bacteria had hampered the development of such tools; however, in the past decade, genetic studies using two model Magnetospirillum species have revealed much about the mechanisms of magnetosome biogenesis. In this Review, we highlight these new insights and place the molecular mechanisms of magnetosome biogenesis in the context of the complex cell biology of Magnetospirillum spp. Furthermore, we discuss the diverse properties of magnetosome biogenesis in other species of magnetotactic bacteria and consider the value of genetically 'magnetizing' non-magnetotactic bacteria. Finally, we discuss future prospects for this highly interdisciplinary and rapidly advancing field.
Topics: Bacterial Proteins; Biotechnology; Crystallization; Ferrosoferric Oxide; Magnetosomes; Magnetospirillum; Organelle Biogenesis
PubMed: 27620945
DOI: 10.1038/nrmicro.2016.99 -
Enzyme and Microbial Technology Jun 2021Phlorizin is a low soluble dihydrochalcone with relevant pharmacological properties. In this study, enzymatic fructosylation was approached to enhance the water...
Phlorizin is a low soluble dihydrochalcone with relevant pharmacological properties. In this study, enzymatic fructosylation was approached to enhance the water solubility of phlorizin, and consequently its bioavailability. Three enzymes were assayed for phlorizin fructosylation in aqueous reactions using sucrose as fructosyl donor. Levansucrase (EC 2.4.1.10) from Gluconacetobacter diazotrophicus (Gd_LsdA) was 6.5-fold more efficient than invertase (EC 3.2.1.26) from Rhodotorula mucilaginosa (Rh_Inv), while sucrose:sucrose 1-fructosyltransferase (EC 2.4.1.99) from Schedonorus arundinaceus (Sa_1-SST) failed to modify the non-sugar acceptor. Gd_LsdA synthesized series of phlorizin mono- di- and tri-fructosides with maximal conversion efficiency of 73 %. The three most abundant products were identified by ESI-MS and NMR analysis as β-D-fructofuranosyl-(2→6)-phlorizin (P1a), phlorizin-4'-O-β-D-fructofuranosyl-(2→6)-D-fructofuranoside (P2c) and phlorizin-4-O-monofructofuranoside (P1b), respectively. Purified P1a was 16 times (30.57 g L at 25 °C) more soluble in water than natural phlorizin (1.93 g L at 25 °C) and exhibited 44.56 % free radical scavenging activity. Gd_LsdA is an attractive candidate enzyme for the scaled synthesis of phlorizin fructosides in the absence of co-solvent.
Topics: Gluconacetobacter; Phlorhizin; Rhodotorula; Sucrose
PubMed: 33992405
DOI: 10.1016/j.enzmictec.2021.109783 -
Journal of Molecular Microbiology and... 2016The anaerobic degradation of 4-alkylbenzoates and 4-alkyltoluenes is to date a rarely reported microbial capacity. The newly isolated Alphaproteobacterium... (Review)
Review
The anaerobic degradation of 4-alkylbenzoates and 4-alkyltoluenes is to date a rarely reported microbial capacity. The newly isolated Alphaproteobacterium Magnetospirillum sp. strain pMbN1 represents the first pure culture demonstrated to degrade 4-methylbenzoate completely to CO2 in a process coupled to denitrification. Differential proteogenomic studies in conjunction with targeted metabolite analyses and enzyme activity measurements elucidated a specific 4-methylbenzoyl-coenzyme A (CoA) pathway in this bacterium alongside the classical central benzoyl-CoA pathway. Whilst these two pathways are analogous, in the former the p-methyl group is retained and its 4-methylbenzoyl-CoA reductase (MbrCBAD) is phylogenetically distinct from the archetypical class I benzoyl-CoA reductase (BcrCBAD). Subsequent global regulatory studies on strain pMbN1 grown with binary or ternary substrate mixtures revealed benzoate to repress the anaerobic utilization of 4-methylbenzoate and succinate. The shared nutritional property of betaproteobacterial 'Aromatoleum aromaticum' pCyN1 and Thauera sp. strain pCyN2 is the anaerobic degradation of the plant-derived hydrocarbon p-cymene (4-isopropyltoluene) coupled to denitrification. Notably, the two strains employ two different peripheral pathways for the conversion of p-cymene to 4-isopropylbenzoyl-CoA as the possible first common intermediate. In 'A. aromaticum' pCyN1 a putative p-cymene dehydrogenase (CmdABC) is proposed to hydroxylate the benzylic methyl group, which is subsequently further oxidized to the CoA-thioester. In contrast, Thauera sp. strain pCyN2 employs a reaction sequence analogous to the known anaerobic toluene pathway, involving a distinct branching (4-isopropylbenzyl)succinate synthase (IbsABCDEF).
Topics: Anaerobiosis; Bacteria, Anaerobic; Benzoates; Biodegradation, Environmental; Magnetospirillum; Phylogeny; Toluene
PubMed: 26960059
DOI: 10.1159/000441144 -
IEEE Transactions on Nanobioscience Oct 2018Magnetotactic bacteria are a group of organisms deeply studied in the last years due to their interesting magnetic behavior and potential applications in nanometrology,...
Magnetotactic bacteria are a group of organisms deeply studied in the last years due to their interesting magnetic behavior and potential applications in nanometrology, hyperthermia, and biosensor devices. One intrinsic common characteristic is the presence, inside the bacteria, of magnetic nanoparticles called magnetosomes. The role of magnetosomes as bacterial tools to orient the bacteria and find new habitats is universally accepted, but the way they develop still is not fully understood. A strain of Magnetospirillum magnetotacticum was grown and investigated at the nanoscale using transmission electron microscopy and atomic/magnetic force microscopy techniques. Magnetosomes were observed as well as long filaments with magnetic response that could be associated to the actin-like filaments being crucial to allow the nanoparticles orientation and magnetosomes formation. To the best of our knowledge, this paper is the first to visualize these reproducible long-range size magnetic crystalline structures.
Topics: Actin Cytoskeleton; Magnetosomes; Magnetospirillum; Microscopy, Atomic Force; Microscopy, Electron, Transmission
PubMed: 30371384
DOI: 10.1109/TNB.2018.2878085 -
ACS Chemical Biology Jan 2017Magnetosomes are protein-rich membrane organelles that encapsulate magnetite or greigite and whose chain alignment enables magnetotactic bacteria (MTB) to sense the... (Review)
Review
Magnetosomes are protein-rich membrane organelles that encapsulate magnetite or greigite and whose chain alignment enables magnetotactic bacteria (MTB) to sense the geomagnetic field. As these bacteria synthesize uniform magnetic particles, their biomineralization mechanism is of great interest among researchers from different fields, from material engineering to medicine. Both magnetosome formation and magnetic particle synthesis are highly controlled processes that can be divided into several crucial steps: membrane invagination from the inner-cell membrane, protein sorting, the magnetosomes' arrangement into chains, iron transport, chemical environment regulation of the magnetosome lumen, magnetic particle nucleation, and finally crystal growth, size, and morphology control. This complex system involves an ensemble of unique proteins that participate in different stages during magnetosome formation, some of which were extensively studied in recent years. Here, we present the current knowledge on magnetosome biosynthesis with a focus on the different proteins and the main biochemical pathways along this process.
Topics: Bacterial Proteins; Magnetosomes; Magnetospirillum; Models, Molecular; Proteobacteria
PubMed: 27930882
DOI: 10.1021/acschembio.6b01000