Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| quantifying the magnetic advantage in magnetotaxis. | magnetotactic bacteria are characterized by the production of magnetosomes, nanoscale particles of lipid bilayer encapsulated magnetite, that act to orient the bacteria in magnetic fields. these magnetosomes allow magneto-aerotaxis, which is the motion of the bacteria along a magnetic field and toward preferred concentrations of oxygen. magneto-aerotaxis has been shown to direct the motion of these bacteria downward toward sediments and microaerobic environments favorable for growth. herein, we ... | 2006 | 16714352 |
| catechol siderophore excretion by magnetotactic bacterium magnetospirillum magneticum amb-1. | siderophore activity was detected in the culture supernatant of the magnetotactic bacterium magnetospirillum magneticum amb-1. here we report the first structural elucidation of a siderophore produced by a magnetotactic bacterium. the structure of the purified compound was 3,4-dihydroxybenzoic acid as determined by nuclear magnetic resonance (nmr) and electro-spray ionization mass spectroscopy (esi-ms). | 2006 | 16781476 |
| how magnetotactic bacteria make magnetosomes queue up. | magnetotactic bacteria contain chains of magnetosomes that comprise a permanent magnetic dipole in each cell. in two separate, recent papers, scheffel et al. and komeili et al. describe the roles of the proteins mamj and mamk in magnetosome chain formation. here, we describe the two studies and highlight questions that must be addressed in future investigations of how magnetotactic bacteria construct their magnetic compass needles. | 2006 | 16782341 |
| novel facultative anaerobic acidotolerant telmatospirillum siberiense gen. nov. sp. nov. isolated from mesotrophic fen. | three facultative anaerobic acidotolerant gram-negative motile spirilla strains designated 26-4b1, 26-2 and k-1 were isolated from mesotrophic siberian fen as a component of methanogenic consortia. the isolates were found to grow chemoorganotrophically on several organic acids and glucose under anoxic and low oxygen pressure in the dark, tolerant up to 5kpa of oxygen. at low oxygen supply, faint autotrophic growth on the h(2):co(2) mixture was also observed. all three isolates were able to fix n ... | 2007 | 16876366 |
| evolutionary diversity of ketoacyl synthases in cellulolytic myxobacterium sorangium. | the diversity of type i polyketide synthases (pkss) in cellulolytic myxobacterium sorangium was explored by assaying the ketoacyl synthases (kss) in 10 sorangium strains with two degenerate primer sets and 64 different ks fragments were obtained. for their deduced amino acid sequences, eight were identical to three known kss from sorangium and magnetospirillum, while the others showed 54-83% identities to the modular ks domains reported from various microorganisms. parts of the sorangium kss tig ... | 2007 | 16899349 |
| origin of magnetosome membrane: proteomic analysis of magnetosome membrane and comparison with cytoplasmic membrane. | prokaryotes are known to have evolved one or more unique organelles. although several hypotheses have been proposed concerning the biogenesis of these intracellular components, the majority of these proposals remains unclear. magnetotactic bacteria synthesize intracellular magnetosomes that are enclosed by lipid bilayer membranes. from the identification and characterization of several surface and transmembrane magnetosome proteins, we have postulated that magnetosomes are derived from the cytop ... | 2006 | 16955514 |
| transcriptional organization and regulation of magnetosome operons in magnetospirillum gryphiswaldense. | genes involved in magnetite biomineralization are clustered within the genomic magnetosome island of magnetospirillum gryphiswaldense. their transcriptional organization and regulation were studied by several approaches. cotranscription of genes within the mamab, mamdc, and mms clusters was demonstrated by reverse transcription-pcr (rt-pcr) of intergenic regions, indicating the presence of long polycistronic transcripts extending over more than 16 kb. the transcription start points of the mamab, ... | 2006 | 16957191 |
| respiratory transformation of nitrous oxide (n2o) to dinitrogen by bacteria and archaea. | n2o is a potent greenhouse gas and stratospheric reactant that has been steadily on the rise since the beginning of industrialization. it is an obligatory inorganic metabolite of denitrifying bacteria, and some production of n2o is also found in nitrifying and methanotrophic bacteria. we focus this review on the respiratory aspect of n2o transformation catalysed by the multicopper enzyme nitrous oxide reductase (n2or) that provides the bacterial cell with an electron sink for anaerobic growth. t ... | 2007 | 17027372 |
| a simple and accurate method for quantification of magnetosomes in magnetotactic bacteria by common spectrophotometer. | a simple apparatus for measuring the magnetism of magnetotactic bacteria was developed with a common laboratory spectrophotometer, which was based on measuring the change in light scattering resulting from cell alignment in a magnetic field. a multiple coils were built around the cuvette holder of the spectrophotometer to compensate geomagnetic field and to generate two mutually perpendicular magnetic fields. in addition, we defined a novel magnetism parameter, r(mag), by modifying the definitio ... | 2007 | 17030397 |
| magnetic separation of cd14+ cells using antibody binding with protein a expressed on bacterial magnetic particles for generating dendritic cells. | herein the potential of a highly efficient cell separation system using bacterial magnetic particles expressing protein a (protein a-bacmps) was demonstrated. protein a was expressed on bacmps using the transmembrane proteins mms13 and maga as anchor molecules. the evaluations of the numbers of bound antibody molecules and binding capabilities of the protein a-bacmps using mms13 indicated that the antibodies were efficiently introduced into protein a-bacmps using mms13 in comparison to maga. in ... | 2006 | 17045961 |
| biogenesis of actin-like bacterial cytoskeletal filaments destined for positioning prokaryotic magnetic organelles. | magnetosomes comprise a magnetic nanocrystal surrounded by a lipid bilayer membrane. these unique prokaryotic organelles align inside magnetotactic bacterial cells and serve as an intracellular compass allowing the bacteria to navigate along the geomagnetic field in aquatic environments. cryoelectron tomography of magnetospirillum strains has revealed that the magnetosome chain is surrounded by a network of filaments that may be composed of mamk given that the filaments are absent in the mamk mu ... | 2006 | 17085581 |
| isolation of the epsilon-caprolactam denitrifying bacteria from a wastewater treatment system manufactured with acrylonitrile-butadiene-styrene resin. | epsilon-caprolactam has high cod and toxicity, so its discharge to natural water and soil systems may lead to an adverse environmental effect on water quality, endangering public health and welfare. this investigation attempts to isolate epsilon-caprolactam denitrifying bacteria from a wastewater treatment system manufactured with acrylonitrile-butadiene-styrene (abs) resin. the goal is to elucidate the effectiveness of isolated pure strain and abs mixed strains in treating epsilon-caprolactam f ... | 2007 | 17161908 |
| deep-etching electron microscopy of cells of magnetospirillum magnetotacticum: evidence for filamentous structures connecting the magnetosome chain to the cell surface. | magnetospirillum magnetotacticum are magnetotactic bacteria that form a single chain of magnetite magnetosomes within its cytoplasm. here, we studied the ultrastructure of m. magnetotacticum by freeze-fracture and deep-etching to understand the spatial correlation between the magnetosome chain and the cell envelope and its possible implications for magnetotaxis. magnetosomes were found mainly near the cell envelope, forming chains that were closely associated with the granular cytoplasmic materi ... | 2007 | 17171472 |
| detection of epidermal growth factor receptor (egfr) mutations in non-small cell lung cancer (nsclc) using a fully automated system with a nano-scale engineered biomagnetite. | a fully automated system using nano-scale engineered biomagnetite was developed to detect mutations in the epidermal growth factor receptor (egfr) gene in non-small cell lung cancer (nsclc). bacterial magnetic particles (bacmps) were isolated from the magnetic bacterium magnetospirillum magneticum amb-1 and conjugated to streptavidin. biotin-labeled target pcr products were then captured with the bacmps, hybridized with the detection probe and detected by fluorescence signaling. the process was ... | 2007 | 17187977 |
| synthesis of magnetite nanoparticles for bio- and nanotechnology: genetic engineering and biomimetics of bacterial magnetosomes. | magnetotactic bacteria (mtb) have the ability to navigate along the earth's magnetic field. this so-called magnetotaxis is a result of the presence of magnetosomes, organelles which comprise nanometer-sized intracellular crystals of magnetite (fe(3)o(4)) enveloped by a membrane. because of their unique characteristics, magnetosomes have a high potential for nano- and biotechnological applications, which require a specifically designed particle surface. the functionalization of magnetosomes is po ... | 2007 | 17295401 |
| molecular analysis of magnetotactic bacteria and development of functional bacterial magnetic particles for nano-biotechnology. | biomineralization is an elaborate process that produces complex nano-structures consisting of organic and inorganic components of uniform size and highly ordered morphology that self-assemble into structures in a hierarchical manner. magnetotactic bacteria synthesize nano-sized magnetite crystals that are highly consistent in size and morphology within bacterial species; each particle is surrounded by a thin organic membrane, which facilitates their use for various biotechnological applications. ... | 2007 | 17306901 |
| expression level of heterologous tat genes is crucial for in vivo reconstitution of a functional tat translocase in escherichia coli. | the tat system has the remarkable capacity of exporting proteins in folded conformation across the cytoplasmic membrane. the functional tat translocase from gram-negative bacteria consists of tata, tatb and tatc proteins. to gain information about the species specificity of the tat translocase, we cloned tat genes from gram-negative pathogens shigella flexneri 2a str. 301, vibrio cholerae el tor n16961, pseudomonas aeruginosa pao1, thermophilic sulfolobus solfataricus p2, thermus thermophilus hb ... | 2007 | 17336443 |
| fluorescent bacterial magnetic nanoparticles as bimodal contrast agents. | the purpose of this study was to assess whether fluorochrome-coupled bacterial magnetic nanoparticles can be used as bimodal contrast agent for both magnetic resonance imaging (mri) and near-infrared fluorescence optical (nirf) imaging of cultured macrophages. | 2007 | 17351430 |
| molecular mechanisms of magnetosome formation. | magnetotactic bacteria are a diverse group of microorganisms with the ability to use geomagnetic fields for direction sensing. this unique feat is accomplished with the help of magnetosomes, nanometer-sized magnetic crystals surrounded by a lipid bilayer membrane and organized into chains via a dedicated cytoskeleton within the cell. because of the special properties of these magnetic crystals, magnetotactic bacteria have been exploited for a variety of applications in diverse disciplines from g ... | 2007 | 17371202 |
| isolation of magnetotactic bacterium wm-1 from freshwater sediment and phylogenetic characterization. | the magnetotactic bacterium was isolated from freshwater sediment from north lake of wuhan. the isolate, designated wm-1, was gram-negative, helical shaped, and studied by means of electron microscopy. the strain wm-1 was 0.2-0.4 microm in diameter and 3-4 microm in length. the dna g + c content was found to be 65.7 mol%. phylogenetic analysis of the 16s rdna gene (accession number dq899734 in genebank) revealed that this isolate was a member ofalphasubdivision of the proteobacteria. strain wm-1 ... | 2007 | 17429614 |
| comparative genome analysis of four magnetotactic bacteria reveals a complex set of group-specific genes implicated in magnetosome biomineralization and function. | magnetotactic bacteria (mtb) are a heterogeneous group of aquatic prokaryotes with a unique intracellular organelle, the magnetosome, which orients the cell along magnetic field lines. magnetotaxis is a complex phenotype, which depends on the coordinate synthesis of magnetosomes and the ability to swim and orient along the direction caused by the interaction with the earth's magnetic field. although a number of putative magnetotaxis genes were recently identified within a conserved genomic magne ... | 2007 | 17449609 |
| dynamics of magnetotactic bacteria in a rotating magnetic field. | the dynamics of the motile magnetotactic bacterium magnetospirillum gryphiswaldense in a rotating magnetic field is investigated experimentally and analyzed by a theoretical model. these elongated bacteria are propelled by single flagella at each bacterial end and contain a magnetic filament formed by a linear assembly of approximately 40 ferromagnetic nanoparticles. the movements of the bacteria in suspension are analyzed by consideration of the orientation of their magnetic dipoles in the fiel ... | 2007 | 17526564 |
| a novel ferric reductase purified from magnetospirillum gryphiswaldense msr-1. | a ferric reductase was purified into an electrophoretically homologous state from magnetospirillum gryphiswaldense msr-1 strain. the enzyme was found within the cytoplasm and associated with the cytoplasmic membrane. the molecular weight of the purified enzyme was calculated as 16.1 kda using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and was almost identical to that calibrated using agarose gel filtration chromatography. it was nadh-dependent and required flavin mononucleotide a ... | 2007 | 17534559 |
| patch clamp and phenotypic analyses of a prokaryotic cyclic nucleotide-gated k+ channel using escherichia coli as a host. | prokaryotic ion channels have been valuable in providing structural models for understanding ion filtration and channel-gating mechanisms. however, their functional examinations have remained rare and usually been carried out by incorporating purified channel protein into artificial lipid membranes. here we demonstrate the utilization of escherichia coli to host the functional analyses by examining a putative cyclic nucleotide-gated k+ channel cloned from magnetospirillum magnetotacticum, mmak. ... | 2007 | 17588940 |
| purified and sterilized magnetosomes from magnetospirillum gryphiswaldense msr-1 were not toxic to mouse fibroblasts in vitro. | to establish a criterion for measuring the purity of purified and sterilized magnetosomes from magnetospirillum gryphiswaldense and to evaluate their toxicity for mouse fibroblasts in vitro. | 2007 | 17594464 |
| the acidic repetitive domain of the magnetospirillum gryphiswaldense mamj protein displays hypervariability but is not required for magnetosome chain assembly. | magnetotactic bacteria navigate along the earth's magnetic field using chains of magnetosomes, which are intracellular organelles comprising membrane-enclosed magnetite crystals. the assembly of highly ordered magnetosome chains is under genetic control and involves several specific proteins. based on genetic and cryo-electron tomography studies, a model was recently proposed in which the acidic mamj magnetosome protein attaches magnetosome vesicles to the actin-like cytoskeletal filament formed ... | 2007 | 17601786 |
| bacterial magnetic particles (bmps)-pei as a novel and efficient non-viral gene delivery system. | non-viral methods of gene delivery, especially using polyethylenimine (pei), have been widely used in gene therapy or dna vaccination. however, the pei system has its own drawbacks, which limits its applications. | 2007 | 17605136 |
| cytoplasmic atpase involved in ferrous ion uptake from magnetotactic bacterium magnetospirillum magneticum amb-1. | a non-magnetic mutant of magnetospirillum magneticum amb-1 (nma61), harboring a defective gene located in orf4 (gene id: amb4111) was generated by transposon mutagenesis. biochemical characterization of the gene product of orf4 revealed that it was localized in the cytoplasm and displayed atpase activity. the ability of nma61 to take up iron was severely compromised. ferrous ion concentration in the medium decreased more with the wild-type than with nma61, while the iron content in the cytoplasm ... | 2007 | 17618623 |
| controlled formation of magnetite crystal by partial oxidation of ferrous hydroxide in the presence of recombinant magnetotactic bacterial protein mms6. | mms6 is a small acidic protein that is tightly associated with bacterial magnetite in magnetospirillum magneticum amb-1. this protein has previously shown iron binding activity, allowing it to generate uniform magnetic crystals by co-precipitation of ferrous and ferric ions. here, magnetite crystals were formed by the partial oxidation of ferrous hydroxide in the presence and absence of mms6. the crystals synthesised were systematically characterised according to their sizes and morphologies usi ... | 2007 | 17720242 |
| construction and preliminary analysis of a metagenomic library from a deep-sea sediment of east pacific nodule province. | the pacific nodule province is a unique ocean area containing an abundance of polymetallic nodules. to explore more genetic information and discover potentially industrial useful genes of the microbial community from this particular area, a cosmid library with an average insert of about 35 kb was constructed from the deep-sea sediment. the bacteria in the cosmid library were composed mainly of proteobacteria including alphaproteobacteria, gammaproteobacteria and deltaproteobacteria. the end sequ ... | 2007 | 17850328 |
| controlled biomineralization by and applications of magnetotactic bacteria. | 2007 | 17869601 | |
| intracellular magnetite biomineralization in bacteria proceeds by a distinct pathway involving membrane-bound ferritin and an iron(ii) species. | 2007 | 17902080 | |
| polymerization of the actin-like protein mamk, which is associated with magnetosomes. | the recombinant actin-like protein mamk was purified from escherichia coli and used as an antigen to generate the anti-mamk antibody. immunostaining studies showed a linear distribution of mamk in magnetospirillum magnetotacticum cells and of mamk in association with magnetosomes. moreover, we demonstrated that mamk polymerizes into filamentous bundles in vitro. | 2007 | 17905974 |
| in vitro and in vivo antitumor effects of doxorubicin loaded with bacterial magnetosomes (dbms) on h22 cells: the magnetic bio-nanoparticles as drug carriers. | hepatocellular carcinoma (hcc) is the most common form of cancer although effective therapeutic strategy especially targeted therapy is lacking. we recently employed bacterial magnetosomes (bms) as the magnetic-targeted drug carrier and found an antitumor effect of doxorubicin (dox)-loaded bms (dbms) in emt-6 and hl60 cell lines. the aim of this study was to evaluate the in vitro and in vivo anti-neoplastic effects of dbms on hepatic cancer. dbms, dox and bms displayed tumor suppression rates of ... | 2007 | 17920762 |
| preliminary investigation of bio-carriers using magnetotactic bacteria. | this paper proposes a novel micro-carrier based on magnetotactic bacteria (mtb). to confirm the feasibility of such carriers, the thrust force of the bacteria is evaluated. by measuring the swimming speed of mc-1 bacteria in an unbounded medium, a thrust of 4 pn generated by a single mc-1 bacterium is found. the effects on the mtb's swimming speed under the control of micro-electromagnets and influenced by the wall effects when each mtb is attached to a microbead are investigated. | 2006 | 17947027 |
| the major magnetosome proteins mamgfdc are not essential for magnetite biomineralization in magnetospirillum gryphiswaldense but regulate the size of magnetosome crystals. | magnetospirillum gryphiswaldense and related magnetotactic bacteria form magnetosomes, which are membrane-enclosed organelles containing crystals of magnetite (fe3o4) that cause the cells to orient in magnetic fields. the characteristic sizes, morphologies, and patterns of alignment of magnetite crystals are controlled by vesicles formed of the magnetosome membrane (mm), which contains a number of specific proteins whose precise roles in magnetosome formation have remained largely elusive. here, ... | 2008 | 17965152 |
| magnetic resonance imaging of fe3o4 nanoparticles embedded in living magnetotactic bacteria for potential use as carriers for in vivo applications. | mc-1 magnetotactic bacteria (mtb) are studied for their potential use as bio-carriers for drug delivery. the exploitation of the flagella combined with nanoparticles magnetite or magnetosomes chain embedded in each bacterium and used to change the swimming direction of each mtb through magnetotaxis provide both propulsion and steering in small diameters blood vessels. but for guiding these mtb towards a target, being capable to image these living bacteria in vivo using an existing medical imagin ... | 2007 | 18002242 |
| rapid magnetosome formation shown by real-time x-ray magnetic circular dichroism. | magnetosomes are magnetite nanoparticles formed by biomineralization within magnetotactic bacteria. although there have been numerous genetic and proteomic studies of the magnetosome-formation process, there have been only limited and inconclusive studies of mineral-phase evolution during the formation process, and no real-time studies of such processes have yet been performed. thus, suggested formation mechanisms still need substantiating with data. here we report the examination of the magneto ... | 2007 | 18032611 |
| mesaconyl-coenzyme a hydratase, a new enzyme of two central carbon metabolic pathways in bacteria. | the coenzyme a (coa)-activated c5-dicarboxylic acids mesaconyl-coa and beta-methylmalyl-coa play roles in two as yet not completely resolved central carbon metabolic pathways in bacteria. first, these compounds are intermediates in the 3-hydroxypropionate cycle for autotrophic co2 fixation in chloroflexus aurantiacus, a phototrophic green nonsulfur bacterium. second, mesaconyl-coa and beta-methylmalyl-coa are intermediates in the ethylmalonyl-coa pathway for acetate assimilation in various bacte ... | 2008 | 18065535 |
| disruption of a fur-like gene inhibits magnetosome formation in magnetospirillum gryphiswaldense msr-1. | in this study, a genomic library of magnetospirillum gryphiswaldense msr-1 strain was constructed and a fur-like gene (encoding fur protein, ferric uptake regulator) was isolated and sequenced. this gene consisted of 420 bp and encoded 139 amino acid residues. to investigate the function of this gene in msr-1, a fur mutant was generated by double crossover with a kanamycin cassette inserted into its coding region. iron uptake and magnetosome formation were dramatically inhibited by disruption of ... | 2007 | 18205608 |
| in chlamydomonas, the loss of nd5 subunit prevents the assembly of whole mitochondrial complex i and leads to the formation of a low abundant 700 kda subcomplex. | in the green alga chlamydomonas reinhardtii, a mutant deprived of complex i enzyme activity presents a 1t deletion in the mitochondrial nd5 gene. the loss of the nd5 subunit prevents the assembly of the 950 kda whole complex i. instead, a low abundant 700 kda subcomplex, loosely associated to the inner mitochondrial membrane, is assembled. the resolution of the subcomplex by sds-page gave rise to 19 individual spots, sixteen having been identified by mass spectrometry analysis. eleven, mainly as ... | 2008 | 18258177 |
| development of a cell surface display system in a magnetotactic bacterium, "magnetospirillum magneticum" amb-1. | bacterial cell surface display is a widely used technology for bioadsorption and for the development of a variety of screening systems. magnetotactic bacteria are unique species of bacteria due to the presence of magnetic nanoparticles within them. these intracellular, nanosized (50 to 100 nm) magnetic nanoparticles enable the cells to migrate and be manipulated by magnetic force. in this work, using this unique characteristic and based on whole-genomic and comprehensive proteomic analyses of th ... | 2008 | 18378651 |
| high-yield growth and magnetosome formation by magnetospirillum gryphiswaldense msr-1 in an oxygen-controlled fermentor supplied solely with air. | magnetotactic bacteria are difficult to grow under defined conditions in culture, which has presented a major obstacle to commercial application of magnetosomes. we studied the relationships among the cell growth, magnetosome formation, dissolved oxygen concentration (do), and the ability to supply oxygen to the cells. mass culture of magnetospirillum gryphiswaldense msr-1 for the production of magnetosomes was established in a 42-l fermentor under the following conditions: (1) sterile air was t ... | 2008 | 18425510 |
| genetics and cell biology of magnetosome formation in magnetotactic bacteria. | the ability of magnetotactic bacteria (mtb) to orient in magnetic fields is based on the synthesis of magnetosomes, which are unique prokaryotic organelles comprising membrane-enveloped, nano-sized crystals of a magnetic iron mineral that are aligned in well-ordered intracellular chains. magnetosome crystals have species-specific morphologies, sizes, and arrangements. the magnetosome membrane, which originates from the cytoplasmic membrane by invagination, represents a distinct subcellular compa ... | 2008 | 18537832 |
| expression of green fluorescent protein fused to magnetosome proteins in microaerophilic magnetotactic bacteria. | the magnetosomes of magnetotactic bacteria are prokaryotic organelles consisting of a magnetite crystal bounded by a phospholipid bilayer that contains a distinct set of proteins with various functions. because of their unique magnetic and crystalline properties, magnetosome particles are potentially useful as magnetic nanoparticles in a number of applications, which in many cases requires the coupling of functional moieties to the magnetosome membrane. in this work, we studied the use of green ... | 2008 | 18539817 |
| formation of magnetite by bacteria and its application. | magnetic particles offer high technological potential since they can be conveniently collected with an external magnetic field. magnetotactic bacteria synthesize bacterial magnetic particles (bacmps) with well-controlled size and morphology. bacmps are individually covered with thin organic membrane, which confers high and even dispersion in aqueous solutions compared with artificial magnetites, making them ideal biotechnological materials. recent molecular studies including genome sequence, mut ... | 2008 | 18559314 |
| noncovalent immobilization of streptavidin on in vitro- and in vivo-biotinylated bacterial magnetic particles. | biotinylated magnetic nanoparticles were constructed by displaying biotin acceptor peptide (bap) or biotin carboxyl carrier protein (bccp) on the surface of bacterial magnetic particles (bacmps) synthesized by magnetospirillum magneticum amb-1. bap-displaying bacmps (bap-bacmps) were extracted from bacterial cells and incubated with biotin and escherichia coli biotin ligase. then the in vitro biotinylation of bap-bacmps was confirmed using alkaline phosphatase-labeled antibiotin antibody. in con ... | 2008 | 18567691 |
| ferrous iron transport protein b gene (feob1) plays an accessory role in magnetosome formation in magnetospirillum gryphiswaldense strain msr-1. | to investigate the role of ferrous iron transport (feo) systems in magnetosome formation, the gene for protein feob (feob1), encoding 704 amino acids, was cloned from magnetotactic bacterium magnetospirillum gryphiswaldense strain msr-1. feob1 constitutes a putative operon with feoa1, and the interval between the two genes is 36 base pairs. a feob1-deficient mutant (deltafeob1) was constructed, and compared with wild-type in terms of iron uptake, iron content and functional complementation. ferr ... | 2008 | 18639631 |
| nanobiotechnology: putting cobalt on the menu. | 2008 | 18654484 | |
| controlled cobalt doping of magnetosomes in vivo. | magnetotactic bacteria biomineralize iron into magnetite (fe3o4) nanoparticles that are surrounded by lipid vesicles. these 'magnetosomes' have considerable potential for use in bio- and nanotechnological applications because of their narrow size and shape distribution and inherent biocompatibility. the ability to tailor the magnetic properties of magnetosomes by chemical doping would greatly expand these applications; however, the controlled doping of magnetosomes has so far not been achieved. ... | 2008 | 18654488 |
| novel method for evaluation of chemicals based on ligand-dependent recruitment of gfp labeled coactivator to estrogen receptor displayed on bacterial magnetic particles. | we established a novel method to evaluate endocrine disrupting chemicals (edcs) by assembling the estrogen receptor-ligand binding domain (erlbd) and gfp labeled coactivator on magnetic nanoparticles. edc can promote or inhibit coactivator recruitment to the ligand-erlbd complex. erlbd was displayed on the surface of nano-sized bacterial magnetic particles (bacmps) produced by the magnetic bacterium, magnetospirillum magneticum amb-1. our method resulted in 38 molecules of erlbd molecules on a b ... | 2008 | 18761123 |
| a mutation upstream of an atpase gene significantly increases magnetosome production in magnetospirillum gryphiswaldense. | a mutant of magnetospirillum gryphiswaldense, nphb, was obtained from a conjugation experiment. an aberrant recombination occurred between a putative elongation factor-g gene (fus-like) of the bacterial chromosome and the chloramphenicol resistant gene (cat) of a suicide vector, psup202. complementary experiments and transcription analysis of genes around the recombinant site showed that the cat promoter enhanced the expression of adenosine triphosphatase gene downstream. adenosine triphosphate ... | 2008 | 18800186 |
| the targeting of endothelial progenitor cells to a specific location within a microfluidic channel using magnetic nanoparticles. | a common problem with the in vivo therapeutic applications of cells is that cells can rapidly disappear into the circulatory system after an injection. magnetic nanoparticles can be used to solve this problem. bacterial magnetic nanoparticles were used in this study for targeting stem cells at a specific location within a microfluidic channel. magnetic nanoparticles were isolated from magnetospirillum sp. amb-1 and delivered to endothelial progenitor cells (epcs). cellular uptake of magnetic nan ... | 2009 | 18836835 |
| novel method for selection of antimicrobial peptides from a phage display library by use of bacterial magnetic particles. | antimicrobial peptides were isolated from a phage display peptide library using bacterial magnetic particles (bacmps) as a solid support. the bacmps obtained from "magnetospirillum magneticum" strain amb-1 consist of pure magnetite (50 to 100 nm in size) and are covered with a lipid bilayer membrane derived from the invagination of the inner membrane. bacmps are easily purified from a culture of magnetotactic bacteria by magnetic separation. approximately 4 x 10(10) pfu of the library phage (com ... | 2008 | 18952877 |
| identification of iron transporters expressed in the magnetotactic bacterium magnetospirillum magnetotacticum. | the magnetotactic bacterium magnetospirillum magnetotacticum ms-1 mineralizes the magnetite (fe(3)o(4)) crystal and organizes a highly ordered intracellular structure, called the magnetosome. however, the iron transport system, which supports the biogenesis of magnetite, is not fully understood. in this study, we first identified the expressions of both the ferric and the ferrous iron transporter proteins in m. magnetotacticum. the cellular protein compositions of ferric and ferrous iron-rich cu ... | 2009 | 18972162 |
| preparation and anti-tumor efficiency evaluation of doxorubicin-loaded bacterial magnetosomes: magnetic nanoparticles as drug carriers isolated from magnetospirillum gryphiswaldense. | bacterial magnetosomes (bms) are commonly used as vehicles for certain enzymes, nucleic acids and antibodies, although they have never been considered drug carriers. to evaluate the clinical potential of bms extracted from magnetospirillum gryphiswaldense in cancer therapy, doxorubicin (dox) was loaded onto the purified bms at a ratio of 0.87 +/- 0.08 mg/mg using glutaraldehyde. the dox-coupled bms (dbms) and bms exhibited uniform sizes and morphology evaluated by tem. the diameters of dbms and ... | 2008 | 18980188 |
| [magnetotactic bacteria's organella, magnetosome-localization, and cytoskeleton]. | 2008 | 19044287 | |
| sinusoidal magnetic field stimulates magnetosome formation and affects mama, mms13, mms6, and maga expression in magnetospirillum magneticum amb-1. | magnetic particles are currently one of the most important materials in the industrial sector, where they have been widely used for biotechnological and biomedical applications. to investigate the effects of the imposed magnetic field on biomineralization in magnetospirillum magneticum amb-1 and to suggest a new approach that enhances formation of magnetosomes, cultures inoculated with either magnetic or nonmagnetic precultures were incubated under a sinusoidal magnetic field or geomagnetic fiel ... | 2008 | 19096456 |
| magnetic separation of melanoma-specific cytotoxic t lymphocytes from a vaccinated melanoma patient's blood using mhc/peptide complex-conjugated bacterial magnetic particles. | target antigen-specific cytotoxic t lymphocytes (ctls) play a key role in anticancer and antivirus immunity in the body, and purification of ctls from heterogeneous immune cells is desired for an efficient cancer immunotherapy and fundamental research. herein, a novel magnetic nanoparticle conjugated with major histocompatibility complex (mhc)/peptide complexes was developed for the magnetic separation of melanoma-specific ctls. to conjugate biotinylated mhc/peptide complexes on nanosized bacter ... | 2009 | 19143499 |
| effects of static magnetic field on magnetosome formation and expression of mama, mms13, mms6 and maga in magnetospirillum magneticum amb-1. | magnetotactic bacteria produce nanometer-size intracellular magnetic crystals. the superior crystalline and magnetic properties of magnetosomes have been attracting much interest in medical applications. to investigate effects of intense static magnetic field on magnetosome formation in magnetospirillum magneticum amb-1, cultures inoculated with either magnetic or non-magnetic pre-cultures were incubated under 0.2 t static magnetic field or geomagnetic field. the results showed that static magne ... | 2009 | 19165820 |
| nano-sized bacterial magnetic particles displaying pyruvate phosphate dikinase for pyrosequencing. | there is a high demand for inexpensive and high-throughput dna sequencing technologies in molecular biology and applied biosciences. in this study, novel nano-sized magnetic particles displaying enzymes for pyrosequencing, a rather novel bioluminometric dna sequencing method based on the sequencing-by-synthesis principle by employing a cascade of several enzymatic reactions, was developed. a highly thermostable enzyme, pyruvate phosphate dikinase (ppdk) which converts ppi to atp was successfully ... | 2009 | 19170242 |
| manganese in biogenic magnetite crystals from magnetotactic bacteria. | magnetotactic bacteria produce either magnetite (fe(3)o(4)) or greigite (fe(3)s(4)) crystals in cytoplasmic organelles called magnetosomes. whereas greigite magnetosomes can contain up to 10 atom% copper, magnetite produced by magnetotactic bacteria was considered chemically pure for a long time and this characteristic was used to distinguish between biogenic and abiogenic crystals. recently, it was shown that magnetosomes containing cobalt could be produced by three strains of magnetospirillum. ... | 2009 | 19187208 |
| direct magnetic separation of immune cells from whole blood using bacterial magnetic particles displaying protein g. | direct separation of target cells from mixed population, such as peripheral blood, umbilical cord blood, and bone marrow, is an essential technique for various therapeutic or diagnosis applications. in this study, novel particles were fabricated, and direct magnetic separation of immune cells from whole blood using such particles was performed. the magnetotactic bacterium magnetospirillum magneticum amb-1 synthesizes intracellular bacterial magnetic particles (bacmps), and protein g was expresse ... | 2009 | 19197981 |
| cobalt ferrite nanocrystals: out-performing magnetotactic bacteria. | magnetotactic bacteria produce exquisitely ordered chains of uniform magnetite (fe(3)o(4)) nanocrystals, and the use of the bacterial mms6 protein allows for the shape-selective synthesis of fe(3)o(4) nanocrystals. cobalt ferrite (cofe(2)o(4)) nanoparticles, on the other hand, are not known to occur in living organisms. here we report on the use of the recombinant mms6 protein in a templated synthesis of cofe(2)o(4) nanocrystals in vitro. we have covalently attached the full-length mms6 protein ... | 2007 | 19206653 |
| comparative analysis of magnetosome gene clusters in magnetotactic bacteria provides further evidence for horizontal gene transfer. | the organization of magnetosome genes was analysed in all available complete or partial genomic sequences of magnetotactic bacteria (mtb), including the magnetosome island (mai) of the magnetotactic marine vibrio strain mv-1 determined in this study. the mai was found to differ in gene content and organization between magnetospirillum species and strains mv-1 or mc-1. although a similar organization of magnetosome genes was found in all mtb, distinct variations in gene order and sequence similar ... | 2009 | 19220405 |
| magnetic separation of human podocalyxin-like protein 1 (hpclp1)-positive cells from peripheral blood and umbilical cord blood using anti-hpclp1 monoclonal antibody and protein a expressed on bacterial magnetic particles. | hemangioblasts are common progenitors of hematopoietic and angiogenic cells, which have been demonstrated in the mouse to possess a unique cell surface marker, podocalyxin-like protein 1 (pclp1) (hara, t. et al., immunity, 11: 567-578. 1999). in this study, we prepared a novel monoclonal antibody against human pclp1 (hpclp1) and attempted to isolate human hematopoietic progenitor cells from umbilical cord blood and peripheral blood using nano-sized bacterial magnetic particles (bacmps) coupled w ... | 2009 | 19293534 |
| high-sensitivity detection of fruit tree viruses using bacterial magnetic particles. | prunus necrotic ring spot virus (pnrsv) and grapevine fanleaf virus (gflv) were detected by fluoroimmunoassay using bacterial magnetic particles (bmps), and a double antibody sandwich enzyme linked immunosorbent assay (das-elisa). for the fluoroimmunoassay, fluorescein isothiocyanate labeled anti-pnrsv antibody or anti-gflv antibody was conjugated onto bmps of magnetospirillum gryphiswaldense msr-1. with this method, a very low minimum antigen concentration (1 x 10(6) dilution of the original sa ... | 2009 | 19341408 |
| characterization of bacterial magnetotactic behaviors by using a magnetospectrophotometry assay. | magnetotactic bacteria have the unique capacity of synthesizing intracellular single-domain magnetic particles called magnetosomes. the magnetosomes are usually organized in a chain that allows the bacteria to align and swim along geomagnetic field lines, a behavior called magnetotaxis. two mechanisms of magnetotaxis have been described. axial magnetotactic cells swim in both directions along magnetic field lines. in contrast, polar magnetotactic cells swim either parallel to the geomagnetic fie ... | 2009 | 19376916 |
| identification of promoters for efficient gene expression in magnetospirillum gryphiswaldense. | to develop an expression system for the magnetotactic bacterium magnetospirillum gryphiswaldense, we compared gene expression from the widely used escherichia coli p(lac) promoter with that from known and predicted genuine m. gryphiswaldense promoters. with the use of green fluorescent protein as a reporter, the highest expression level was observed with the magnetosomal p(mamdc) promoter. we demonstrate that this promoter can be used for the expression of modified magnetosome proteins to genera ... | 2009 | 19395573 |
| targeted distribution of bacterial magnetosomes isolated from magnetospirillum gryphiswaldense msr-1 in healthy sprague-dawley rats. | bacterial magnetosomes (bms) have drawn great interest as novel magnetic targeted carriers and have been widely used as carriers for enzymes, nucleic acids and antibodies experimentally. however, bms have rarely been employed as drug carriers in vivo mainly due to the unclear biocompatibility and pharmacokinetics of bms. in this study, we provided a unique effective method for purification and sterilization of bms. the bms obtained exhibited sterility, high purity, narrowed size-distribution, un ... | 2009 | 19435053 |
| contributions of phosphate to dna adsorption/desorption behaviors on aminosilane-modified magnetic nanoparticles. | the adsorption and desorption behaviors of dna on aminosilane-modified magnetic nanoparticles were investigated by altering both type of anions and solvation state to achieve eficient recovery of dna useful for subsequent polymerase chain reaction (pcr) analysis. the effects of multiple anions in accordance with the hofmeister ion series were determined to clarify the contribution of phosphate ions on the effective desorption of dna from aminosilane surfaces. efficient dna desorption (85% recove ... | 2009 | 19437706 |
| effect of oxidative stress on the growth of magnetic particles in magnetospirillum magneticum. | individual magnetosome-containing magnetic mineral particles (mmp) from magnetotactic bacteria grow rapidly such that only a small fraction (5%) of all magnetosomes contain dwarf (< or =20 nm) mmp. studies of the developmental stages in the growth of mmp are difficult due to the absence of techniques to separate dwarf from mature particles and because the former are sensitive to extraction procedures. here, o2 stress was used to inhibit mmp expression in magnetospirillum magneticum strain amb-1. ... | 2009 | 19440983 |
| magnetosome formation and expression of mama, mms13, mms6 and maga in magnetospirillum magneticum amb-1 exposed to pulsed magnetic field. | to investigate the effects of pulsed magnetic field on magnetosome formation in magnetospirillum magneticum amb-1, cultures inoculated with either mangetic or non-magnetic pre-cultures were incubated under 1 mt pulsed magnetic field. magnetism of cells was measured by using spectrophotometer coupled with applied magnetic fields and the values were described as c(mag). magnetosome in cells was counted by transmission electron microscopy observation. the results showed that pulsed magnetic field d ... | 2009 | 19459005 |
| assemblies of aligned magnetotactic bacteria and extracted magnetosomes: what is the main factor responsible for the magnetic anisotropy? | the origin of the magnetic anisotropy is explained in an assembly of aligned magnetic nanoparticles. for that, nanoparticles synthesized biologically by magnetospirillum magneticum amb-1 magnetotactic bacteria are used. for the first time, it is possible to differentiate between the two contributions arising from the alignment of the magnetosome easy axes and the strength of the magnetosome dipolar interactions. the magnetic anisotropy is shown to arise mainly from the dipolar interactions betwe ... | 2009 | 19459692 |
| on the change in bacterial size and magnetosome features for magnetospirillum magnetotacticum (ms-1) under high concentrations of zinc and nickel. | the characteristic size, shape and specific alignment of magnetite crystals synthesized by magnetotactic bacteria is a highly coordinated process with precise control over magnetosome vesicle formation, uptake and transport of fe, and magnetite biomineralization. magnetosome membranes along with some specific membrane proteins regulate crystal nucleation and morphology of magnetite. several previous works have indicated that the morphology of mature magnetite crystals is largely unaffected by en ... | 2009 | 19500838 |
| proteomic analysis of irregular, bullet-shaped magnetosomes in the sulphate-reducing magnetotactic bacterium desulfovibrio magneticus rs-1. | recent molecular studies on magnetotactic bacteria have identified a number of proteins associated with bacterial magnetites (magnetosomes) and elucidated their importance in magnetite biomineralisation. however, these analyses were limited to magnetotactic bacterial strains belonging to the alpha-subclass of proteobacteria. we performed a proteomic analysis of magnetosome membrane proteins in desulfovibrio magneticus strain rs-1, which is phylogenetically classified as a member of the delta-pro ... | 2009 | 19579222 |
| microbial sulfide oxidation in the oxic-anoxic transition zone of freshwater sediment: involvement of lithoautotrophic magnetospirillum strain j10. | the oxic-anoxic transition zone (oatz) of freshwater sediments, where opposing gradients exist of reduced iron and sulfide with oxygen, creates a suitable environment for microorganisms that derive energy from the oxidation of iron or sulfide. gradient microcosms incubated with freshwater sediment showed rapid microbial turnover of sulfide and oxygen compared with sterile systems. microcosms with fes as a substrate also showed growth at the oatz and subsequent dilution series resulted in the iso ... | 2009 | 19659746 |
| visualizing implanted tumors in mice with magnetic resonance imaging using magnetotactic bacteria. | to determine if magnetotactic bacteria can target tumors in mice and provide positive contrast for visualization using magnetic resonance imaging. | 2009 | 19671860 |
| whole genome sequence of desulfovibrio magneticus strain rs-1 revealed common gene clusters in magnetotactic bacteria. | magnetotactic bacteria are ubiquitous microorganisms that synthesize intracellular magnetite particles (magnetosomes) by accumulating fe ions from aquatic environments. recent molecular studies, including comprehensive proteomic, transcriptomic, and genomic analyses, have considerably improved our hypotheses of the magnetosome-formation mechanism. however, most of these studies have been conducted using pure-cultured bacterial strains of alpha-proteobacteria. here, we report the whole-genome seq ... | 2009 | 19675025 |
| magnetic resonance imaging of cells overexpressing maga, an endogenous contrast agent for live cell imaging. | molecular imaging with magnetic resonance imaging (mri) may benefit from the ferrimagnetic properties of magnetosomes, membrane-enclosed iron biominerals whose formation in magnetotactic bacteria is encoded by multiple genes. one such gene is maga, a putative iron transporter. we have examined expression of maga in mouse neuroblastoma n2a cells and characterized their response to iron loading and cellular imaging by mri. maga expression augmented both prussian blue staining and the elemental iro ... | 2009 | 19723470 |
| effects of pulsed magnetic field on the formation of magnetosomes in the magnetospirillum sp. strain amb-1. | magnetotactic bacteria are a diverse group of microorganisms which possess one or more chains of magnetosomes and are endowed with the ability to use geomagnetic fields for direction sensing, thus providing a simple and excellent model for the study of magnetite-based magnetoreception. in this study, a 50 hz, 2 mt pulsed magnetic field (pmf) was applied to study the effects on the formation of magnetosomes in magnetospirillum sp. strain amb-1. the results showed that the cellular magnetism (r(ma ... | 2010 | 19780093 |
| in vivo display of a multisubunit enzyme complex on biogenic magnetic nanoparticles. | magnetosomes are unique bacterial organelles comprising membrane-enveloped magnetic crystals produced by magnetotactic bacteria. because of several desirable chemical and physical properties, magnetosomes would be ideal scaffolds on which to display highly complicated biological complexes artificially. as a model experiment for the functional expression of a multisubunit complex on magnetosomes, we examined the display of a chimeric bacterial rnase p enzyme composed of the protein subunit (c5) o ... | 2009 | 19837839 |
| anaerobic metabolism of phenol in proteobacteria and further studies of phenylphosphate carboxylase. | anaerobic phenol metabolism was studied in three facultative aerobic denitrifying bacteria, thauera aromatica, "aromatoleum aromaticum" strain ebn1 (betaproteobacteria), and magnetospirillum sp. (alphaproteobacterium). all species formed phenylphosphate and contained phenylphosphate carboxylase but not phenol carboxylase activity. this is in contrast to direct phenol carboxylation by fermenting bacteria. antisera raised against subunits of the thauera phenylphosphate synthase and phenylphosphate ... | 2009 | 19838679 |
| [protein display onto nano-sized bacterial magnetic particles for receptor analysis]. | magnetic particles offer vast potential in ushering new techniques, especially in biomedical applications, as they can be easily manipulated by magnetic force. magnetotactic bacteria synthesize nano-sized biomagnetites, otherwise known as bacterial magnetic particles (bacmps) that are individually enveloped by a lipid bilayer membrane. bacmps are ultrafine magnetite crystals (50-100 nm diameters) with uniform morphology produced by magnetospirillum magneticum amb-1. based on our elucidations on ... | 2009 | 19881203 |
| control of the morphology and size of magnetite particles with peptides mimicking the mms6 protein from magnetotactic bacteria. | mms6 is a dominant protein that tightly associates with the surface of bacterial magnetites in magnetospirillum magneticum amb-1. the protein has previously been shown to mediate the formation of uniform magnetite crystals of cubo-octahedral morphology consisting of (1 1 1) and (1 0 0) crystal faces with a narrow size distribution during chemical magnetite synthesis. in order to understand the role of this protein in chemical magnetite synthesis, magnetite formation was investigated using synthe ... | 2010 | 20006848 |
| deletion of the ftsz-like gene results in the production of superparamagnetic magnetite magnetosomes in magnetospirillum gryphiswaldense. | magnetotactic bacteria (mtb) synthesize unique organelles termed "magnetosomes," which are membrane-enclosed structures containing crystals of magnetite or greigite. magnetosomes form a chain around mamk cytoskeletal filaments and provide the basis for the ability of mtb to navigate along geomagnetic field lines in order to find optimal microaerobic habitats. genomes of species of the mtb genus magnetospirillum, in addition to a gene encoding the tubulin-like ftsz protein (involved in cell divis ... | 2010 | 20023033 |
| inducible expression of transmembrane proteins on bacterial magnetic particles in magnetospirillum magneticum amb-1. | bacterial magnetic particles (bacmps) produced by the magnetotactic bacterium magnetospirillum magneticum amb-1 are used for a variety of biomedical applications. in particular, the lipid bilayer surrounding bacmps has been reported to be amenable to the insertion of recombinant transmembrane proteins; however, the display of transmembrane proteins in bacmp membranes remains a technical challenge due to the cytotoxic effects of the proteins when they are overexpressed in bacterial cells. in this ... | 2010 | 20038711 |
| preparation of genomic dna from a single species of uncultured magnetotactic bacterium by multiple-displacement amplification. | magnetotactic bacteria comprise a phylogenetically diverse group that is capable of synthesizing intracellular magnetic particles. although various morphotypes of magnetotactic bacteria have been observed in the environment, bacterial strains available in pure culture are currently limited to a few genera due to difficulties in their enrichment and cultivation. in order to obtain genetic information from uncultured magnetotactic bacteria, a genome preparation method that involves magnetic separa ... | 2010 | 20081000 |
| reduced inorganic sulfur oxidation supports autotrophic and mixotrophic growth of magnetospirillum strain j10 and magnetospirillum gryphiswaldense. | magnetotactic bacteria are present at the oxic-anoxic transition zone where opposing gradients of oxygen and reduced sulfur and iron exist. growth of non-magnetotactic lithoautotrophic magnetospirillum strain j10 and its close relative magnetotactic magnetospirillum gryphiswaldense was characterized in microaerobic continuous culture. both strains were able to grow in mixotrophic (acetate + sulfide) and autotrophic (sulfide or thiosulfate) conditions. autotrophically growing cells completely con ... | 2010 | 20105221 |
| a second actin-like mamk protein in magnetospirillum magneticum amb-1 encoded outside the genomic magnetosome island. | magnetotactic bacteria are able to swim navigating along geomagnetic field lines. they synthesize ferromagnetic nanocrystals that are embedded in cytoplasmic membrane invaginations forming magnetosomes. regularly aligned in the cytoplasm along cytoskeleton filaments, the magnetosome chain effectively forms a compass needle bestowing on bacteria their magnetotactic behaviour. a large genomic island, conserved among magnetotactic bacteria, contains the genes potentially involved in magnetosome for ... | 2010 | 20161777 |
| cre-lox-based method for generation of large deletions within the genomic magnetosome island of magnetospirillum gryphiswaldense. | magnetosome biomineralization and magnetotaxis in magnetotactic bacteria are controlled by numerous, mostly unknown gene functions that are predominantly encoded by several operons located within the genomic magnetosome island (mai). genetic analysis of magnetotactic bacteria has remained difficult and requires the development of novel tools. we established a cre-lox-based deletion method which allows the excision of large genomic fragments in magnetospirillum gryphiswaldense. two conjugative su ... | 2010 | 20173068 |
| isolation and characterization of a marine magnetotactic spirillum axenic culture qh-2 from an intertidal zone of the china sea. | magnetotactic bacteria (mtb) are ubiquitous in aquatic habitats. because of their fastidious requirements for growth conditions, only very few axenic mtb cultures have been obtained worldwide. in this study, we report a novel marine magnetotactic spirillum axenic culture, designated as qh-2, isolated from the china sea. it was able to grow in semi-solid or liquid chemically defined medium. the cells were amphitrichously flagellated and contained one single magnetosome chain with an average numbe ... | 2010 | 20178843 |
| comprehensive genetic dissection of the magnetosome gene island reveals the step-wise assembly of a prokaryotic organelle. | although membrane-bounded compartments are commonly considered a unique eukaryotic characteristic, many species of bacteria have organelles. compartmentalization is well studied in eukaryotes; however, the molecular factors and processes leading to organelle formation in bacteria are poorly understood. we use the magnetosome compartments of magnetotactic bacteria as a model system to investigate organelle biogenesis in a prokaryotic system. the magnetosome is an invagination of the cell membrane ... | 2010 | 20212111 |
| purification of the m. magneticum strain amb-1 magnetosome associated protein mamadelta41. | magnetotactic bacteria comprise a diverse group of aquatic microorganisms that are able to orientate themselves along geomagnetic fields. this behavior is believed to aid their search for suitable environments (1). this capability is conferred by the magnetosome, a subcellular organelle that consists of a linear-chain assembly of lipid vesicles each able to biomineralize and enclose a ~50-nm crystal of magnetite or greigite. a principle component of the magnetosome that was shown to be required ... | 2010 | 20339346 |
| identification and functional characterization of liposome tubulation protein from magnetotactic bacteria. | magnetotactic bacteria synthesize intracellular magnetosomes that are comprised of membrane-enveloped magnetic crystals. in this study, to identify the early stages of magnetosome formation, we isolated magnetosomes containing small magnetite crystals and those containing regular-sized magnetite crystals from magnetospirillum magneticum amb-1. this was achieved by using a novel size fractionation technique, resulting in the identification of a characteristic protein (amb1018/mamy) from the small ... | 2010 | 20345667 |
| surface modification of magnetic nanoparticles using asparagines-serine polypeptide designed to control interactions with cell surfaces. | surface modification is an important part of the fabrication of nanoparticles that have specific properties and functions. here we describe the development of a functional polypeptide and a simple available technology for surface modification of nanoparticles. a ns polypeptide, which is 100 amino acids composed of repeated units of four asparagine and one serine residue (ns), as a molecule for nanoparticle surface modification was designed. modification of the surface of a magnetic nanoparticle ... | 2010 | 20363023 |
| [geographical distribution of magnetotactic bacteria]. | magnetotactic bacteria (mtb) are widely distributed in aquatic environments. to assess the correlation between their evolutionary relatedness and geographic distribution, we analyzed 239 16s rdna sequences available in the genbank, and constructed phylogenetic trees based on the sequences. after elimination of redundant sequences by grouping those with identity > 97% into a single one, we analyzed in detail total 139 16s rdna sequences, including 55 from marine mtb and 82 from freshwater sequenc ... | 2010 | 20391717 |
| visualization and structural analysis of the bacterial magnetic organelle magnetosome using atomic force microscopy. | the unique ability of magnetotactic bacteria to navigate along a geomagnetic field is accomplished with the help of prokaryotic organelles, magnetosomes. the magnetosomes have well-ordered chain-like structures, comprising membrane-enveloped, nano-sized magnetic crystals, and various types of specifically associated proteins. in this study, we applied atomic force microscopy (afm) to investigate the spatial configuration of isolated magnetosomes from magnetospirillum magneticum amb-1 in near-nat ... | 2010 | 20439702 |
| an mcp-like protein interacts with the mamk cytoskeleton and is involved in magnetotaxis in magnetospirillum magneticum amb-1. | magnetotactic bacteria have the unique capacity of aligning and swimming along geomagnetic field lines, a behavior called magnetotaxis. although this behavior has been observed for 40 years, little is known about its mechanism. magnetotactic bacteria synthesize unique organelles, magnetosomes, which are magnetic crystals enveloped by membrane. they form chains with the help of the filamentous cytoskeletal protein mamk and impart a net magnetic-dipole moment to the bacterium. the current model pr ... | 2010 | 20471399 |
| cell division in magnetotactic bacteria splits magnetosome chain in half. | cell division in magnetotactic bacteria has attracted much interest, speculation and hypothesis with respect to the biomineralised chains of magnetic iron-oxide particles known as magnetosomes. here we report direct transmission electron microscopy (tem) evidence that division occurs at a central point of the cell and the chain, cleaving the magnetosome chain in two. additionally, the new magnetosome chain relocates rapidly to the centre of the daughter cell and the number of magnetosomes is dir ... | 2010 | 20473965 |