共查询到20条相似文献,搜索用时 15 毫秒
1.
Dennis A. Bazylinski Anthony J. Garratt-Reed Afshin Abedi Richard B. Frankel 《Archives of microbiology》1993,160(1):35-42
Greigite (Fe3S4) and pyrite (FeS2) particles in the magnetosomes of a many-celled, magnetotactic prokaryote (MMP), common in brackish-to-marine, sulfidic, aquatic habitats, contained relatively high concentrations of copper which ranged from about 0.1 to 10 atomic per cent relative to iron. In contrast, the greigite particles in the magnetosomes of a curved magnetotactic bacterium collected from the same sampling site did not contain significant levels of copper. The ability of the MMP to biomineralize copper within its magnetosomes appeared to be limited to that organism and dependent upon the site from which it was collected. Although the chemical mechanism and physiological function of copper accumulation in the magnetosomes of the MMP is unclear, the presence of copper is the first evidence that another transition metal ion could be incorporated in the mineral phase of the magnetosomes of a magnetotactic bacterium.Abbreviation MMP
many-celled magnetotactic prokaryote 相似文献
2.
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 μm in diameter
and 3–4 μm 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 ofαsubdivision of the Proteobacteria. Strain WM-1 was closely related (97.7%) to Magnetospirillum sp. AMB-1. Randomly amplified polymorphic DNA analysis showed that these two strains were in fact different strains. Electron
diffraction patterns of WM-1 magnetosomes indicated that the magnetosomes were composed of magnetite. The magnetosomes from
WM-1 were cuboidal in shape as observed by electron microscopy. Statistical analysis of magnetite crystals from WM-1 showed
narrow asymmetric size distribution. The average number of magnetosomes in each WM-1 bacterium was 8 ± 3.4. The average length
of magnetosomes in WM-1 was 54 ± 12.3 nm and the average width is 43 ± 10.9 nm. These data showed that the grains in WM-1
were single-domain crystals. 相似文献
3.
4.
Wenbing Li Longjiang Yu Pengpeng Zhou Min Zhu 《World journal of microbiology & biotechnology》2007,23(10):1489-1492
Summary A helical shaped bacterium capable of producing magnetosomes, designated WM-1, was isolated from freshwater sediment through
an improved isolated method that combined magnetic separation and the “race track” method. The strain WM-1 was Gram-negative,
0.2–0.4 μm in diameter and 3–4 μm in length. The strain WM-1 was identified as genus Magnetospirillum in the α-Proteobacteria according to the sequence analysis of the 16S rDNA, the morphology and physiological characteristics.
The shape of the magnetosomes in WM-1was cuboidal by electron microscopy. Statistical analysis of WM-1 magnetosome crystals
showed that the average number of magnetosomes in a WM-1 bacterium was 8 ± 3.4, and the average length was 54 ± 12.3 nm, and
the average width was 43 ± 10.9 nm. 相似文献
5.
Elodie C.T. Descamps Caroline L. Monteil Nicolas Menguy Nicolas Ginet David Pignol Dennis A. Bazylinski Christopher T. Lefèvre 《Systematic and applied microbiology》2017,40(5):280-289
A magnetotactic bacterium, designated strain BW-1T, was isolated from a brackish spring in Death Valley National Park (California, USA) and cultivated in axenic culture. The Gram-negative cells of strain BW-1T are relatively large and rod-shaped and possess a single polar flagellum (monotrichous). This strain is the first magnetotactic bacterium isolated in axenic culture capable of producing greigite and/or magnetite nanocrystals aligned in one or more chains per cell. Strain BW-1T is an obligate anaerobe that grows chemoorganoheterotrophically while reducing sulfate as a terminal electron acceptor. Optimal growth occurred at pH 7.0 and 28 °C with fumarate as electron donor and carbon source. Based on its genome sequence, the G + C content is 40.72 mol %. Phylogenomic and phylogenetic analyses indicate that strain BW-1T belongs to the Desulfobacteraceae family within the Deltaproteobacteria class. Based on average amino acid identity, strain BW-1T can be considered as a novel species of a new genus, for which the name Desulfamplus magnetovallimortis is proposed. The type strain of D. magnetovallimortis is BW-1T (JCM 18010T–DSM 103535T). 相似文献
6.
7.
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 cytoplasmic fraction of NMA61 was much lower than the wild-type strain. This cytoplasmic ATPase is essential for iron trafficking within M. magneticum AMB-1. 相似文献
8.
9.
10.
Lactococcus lactis is a Gram-positive bacteria, which belongs to the group of lactic acid bacteria among which several genera play an essential role in the manufacture of food products. Cytosolic proteins of L. lactis IL1403 cultivated in M17 broth have been resolved by two-dimensional gel electrophoresis using two pH gradients (pH 4-7, 4.5-5.5). More than 230 spots were identified by peptide mass fingerprints, corresponding to 25% of the predicted acid proteome. The present study made it possible to describe at the proteome level a significant number of cellular pathways (glycolysis, fermentation, nucleotide metabolism, proteolysis, fatty acid and peptidoglycan synthesis) related to important physiological processes and technological properties. It also indicated that the fermentative metabolism, which characterizes L. lactis is associated with a high expression of glycolytic enzymes. Thirty-four proteins were matched to open reading frames for which there is no assigned function. The comparison at the proteome level of two strains of L. lactis showed an important protein polymorphism. The comparison of the proteomes of glucose- and lactose-grown cells revealed an unexpected link between the nature of the carbon source and the metabolism of pyrimidine nucleotides. 相似文献
11.
Magnetotactic bacteria synthesize uniform-sized and regularly shaped magnetic nanoparticles in their organelles termed magnetosomes. Homeostasis of the magnetosome lumen must be maintained for its role accomplishment. Here, we developed a method to estimate the pH of a single living cell of the magnetotactic bacterium Magnetospirillum magneticum AMB-1 using a pH-sensitive fluorescent protein E2GFP. Using the pH measurement, we estimated that the cytoplasmic pH was approximately 7.6 and periplasmic pH was approximately 7.2. Moreover, we estimated pH in the magnetosome lumen and cytoplasmic surface using fusion proteins of E2GFP and magnetosome-associated proteins. The pH in the magnetosome lumen increased during the exponential growth phase when magnetotactic bacteria actively synthesize magnetite crystals, whereas pH at the magnetosome surface was not affected by the growth stage. This live-cell pH measurement method will help for understanding magnetosome pH homeostasis to reveal molecular mechanisms of magnetite biomineralization in the bacterial organelle. 相似文献
12.
13.
14.
15.
Kathrin Jansen Rudolf K. Thauer Fritz Widdel Georg Fuchs 《Archives of microbiology》1984,138(3):257-262
Desulfovibrio baarsii is a sulfate reducing bacterium, which can grown on formate plus sulfate as sole energy source and formate and CO2 as sole carbon sources. It is shown by 14C labelling studies that more than 60% of the cell carbon is derived from CO2 and the rest from formate. The cells thus grow autotrophically. Labelling studies with [14C]acetate, 14CO and [14C]formate indicate that CO2 fixation does not proceed via the Calvin cycle. The labelling patterns of alanine, aspartate, glutamate, and glucosamine indicate that acetate (or activated acetic acid) is an early intermediate in formate and CO2 assimilation; the methyl group of acetate is derived from formate, and the carboxyl group from CO2 via CO; pyruvate is formed from acetyl-CoA by reductive carboxylation. The capacity to synthesize an acetate unit from two C1-compounds obviously distinguishes D. baarsii from those Desulfovibrio species, which require acetate as a carbon source in addition to CO2. 相似文献
16.
17.
The transmembrane proton gradient of the sulfate-reducing bacterium Desulfovibrio desulfuricans strain CSN has been determined by in vivo31P nuclear magnetic resonance (NMR) spectroscopy in the absence of dioxygen. At pH 7.0 in the medium (pHex) the intracellular pH (pHin) was 7.5. By lowering pHex to 5.9 pHin decreased to 7.1. At pHex greater than 7.7 the transmembrane proton gradient (pH) was zero. The uncouplers 3,3,4,5-tetrachlorosalicylanilide (TCS) and carbonylcyanide-m-chlorophenylhydrazone (CCCP), or the permeant anion thiocyanate caused complete dissipation of pH.Abbreviations
CCCP
carbonylcyanide-m-chlorophenylhydrazone
-
TCS
3,3,4,5-tetrachlorosalicylanilide
-
MOPS
3-(N-morpholino)-propanesulfonic acid
-
P
i
inorganic phosphate
-
pH
in (pHex)
intracellular (extracellular) pH
- pH
transmembrane proton gradient (pHin-pHex)
-
electrochemical membrane potential
-
chemical shift in parts per million
-
NMR
nuclear magnetic resonance 相似文献
18.
Pilar Junier Thomas Junier Sheila Podell David R. Sims John C. Detter Athanasios Lykidis Cliff S. Han Nicholas S. Wigginton Terry Gaasterland Rizlan Bernier‐Latmani 《Environmental microbiology》2010,12(10):2738-2754
Spore‐forming, Gram‐positive sulfate‐reducing bacteria (SRB) represent a group of SRB that dominates the deep subsurface as well as niches in which resistance to oxygen and dessication is an advantage. Desulfotomaculum reducens strain MI‐1 is one of the few cultured representatives of that group with a complete genome sequence available. The metabolic versatility of this organism is reflected in the presence of genes encoding for the oxidation of various electron donors, including three‐ and four‐carbon fatty acids and alcohols. Synteny in genes involved in sulfate reduction across all four sequenced Gram‐positive SRB suggests a distinct sulfate‐reduction mechanism for this group of bacteria. Based on the genomic information obtained for sulfate reduction in D. reducens, the transfer of electrons to the sulfite and APS reductases is proposed to take place via the quinone pool and heterodisulfide reductases respectively. In addition, both H2‐evolving and H2‐consuming cytoplasmic hydrogenases were identified in the genome, pointing to potential cytoplasmic H2 cycling in the bacterium. The mechanism of metal reduction remains unknown. 相似文献
19.
David T. Welsh Yvonne E. Lindsay Pierre Caumette Rodney A. Herbert john Hannan 《FEMS microbiology letters》1996,140(2-3):203-207
Abstract A gene ( ERG11 ) encoding cytochrome P450 sterol 14α-demethylase (P45014DM ) was isolated from the maize pathogen, Ustilago maydis , by amplifying part of the coding region of the gene using PCR and by employing the amplified DNA fragment as a hybridization probe to recover the complete gene from an U. maydis λEMBL3 genomic library. The deduced amino acid sequence of the U. maydis gene showed homology to P45014DM s from other organisms and contained specific motifs which were hallmarks of P450s. Expression of the gene in an U. maydis mutant (A20) deficient in P45014DM led to only a partial restoration of P45014DM activity. Accumulation of ergosta-7,22-dienol and ergost-7-enol in A20 transformants containing the ERG11 gene implied that an additional mutation affecting sterol Δ 5,6 -desaturase activity accompanied the P45014DM lesion. 相似文献
20.
Mauricio Toro‐Nahuelpan Laura Corrales‐Guerrero Theresa Zwiener Manuel Osorio‐Valeriano Frank‐Dietrich Müller Jürgen M. Plitzko Marc Bramkamp Martin Thanbichler Dirk Schüler 《Molecular microbiology》2019,112(5):1423-1439
Cell division needs to be tightly regulated and closely coordinated with other cellular processes to ensure the generation of fully viable offspring. Here, we investigate division site placement by the cell division regulator MipZ in the alphaproteobacterium Magnetospirillum gryphiswaldense, a species that forms linear chains of magnetosomes to navigate within the geomagnetic field. We show that M. gryphiswaldense contains two MipZ homologs, termed MipZ1 and MipZ2. MipZ2 localizes to the division site, but its absence does not cause any obvious phenotype. MipZ1, by contrast, forms a dynamic bipolar gradient, and its deletion or overproduction cause cell filamentation, suggesting an important role in cell division. The monomeric form of MipZ1 interacts with the chromosome partitioning protein ParB, whereas its ATP‐dependent dimeric form shows non‐specific DNA‐binding activity. Notably, both the dimeric and, to a lesser extent, the monomeric form inhibit FtsZ polymerization in vitro. MipZ1 thus represents a canonical gradient‐forming MipZ homolog that critically contributes to the spatiotemporal control of FtsZ ring formation. Collectively, our findings add to the view that the regulatory role of MipZ proteins in cell division is conserved among many alphaproteobacteria. However, their number and biochemical properties may have adapted to the specific needs of the host organism. 相似文献