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Journal of Bacteriology Feb 1977Membranes from Spirillum itersonii reduce ferric iron to ferrous iron with reduced nicotinamide adenine dinucleotide or succinate as a source of reductant. Iron...
Membranes from Spirillum itersonii reduce ferric iron to ferrous iron with reduced nicotinamide adenine dinucleotide or succinate as a source of reductant. Iron reduction was measured spectrophotometrically at 562 nm using ferrozine, which chelates ferrous iron specifically. Reduced nicotinamide adenine dinucleotide or succinate was also effective as a source of iron. The effects of respiratory inhibitors suggested that reduction of iron occurs at one or more sites on the respiratory chain before cytochrome c. Reduction of iron and synthesis of protoheme with the physiological reductants were also observed with crude extracts of other bacteria, including Rhodopseudomonas spheroides, Rhodopseudomonas capsulata, Paracoccus denitrificans, and Escherichia coli. The effect of oxygen upon reduction of iron and formation of protoheme was examined with membranes from S. itersonii, using succinate as a source of reductant. Both systems were inhibited by oxygen, but this effect was completely reversed by addition of antimycin A. We conclude that reduced components of the respiratory chain serve as reductants for ferric iron, but with oxygen present they are oxidized preferentially by the successive members of the chain. This could be a mechanism for regulating synthesis of heme and cytochrome by oxygen.
Topics: Antimycin A; Cyanides; Dithiothreitol; Escherichia coli; Ferrochelatase; Ferrozine; Heme; Hydroxyquinolines; Iron; Membranes; NAD; Oxidation-Reduction; Oxidoreductases; Oxygen; Paracoccus denitrificans; Rhodopseudomonas; Rotenone; Spirillum; Subcellular Fractions; Succinates
PubMed: 190208
DOI: 10.1128/jb.129.2.815-820.1977 -
Bacteriological Reviews Mar 1976
Review
Topics: Bacteriophages; Carbohydrate Metabolism; Cell Wall; Chemotaxis; Culture Media; DNA, Bacterial; Flagella; Movement; Oxygen Consumption; Spirillum
PubMed: 773367
DOI: 10.1128/br.40.1.55-115.1976 -
MSystems Jun 2021Among the thousands of species that comprise marine bacterioplankton communities, most remain functionally obscure. One key cosmopolitan group in this understudied...
Among the thousands of species that comprise marine bacterioplankton communities, most remain functionally obscure. One key cosmopolitan group in this understudied majority is the OM252 clade of . Although frequently found in sequence data and even previously cultured, the diversity, metabolic potential, physiology, and distribution of this clade has not been thoroughly investigated. Here, we examined these features of OM252 bacterioplankton using a newly isolated strain and genomes from publicly available databases. We demonstrated that this group constitutes a globally distributed novel genus (" Halomarinus"), sister to , comprising two subclades and multiple distinct species. OM252 organisms have small genomes (median, 2.21 Mbp) and are predicted obligate aerobes capable of alternating between chemoorganoheterotrophic and chemolithotrophic growth using reduced sulfur compounds as electron donors. Subclade I genomes encode genes for the Calvin-Benson-Bassham cycle for carbon fixation. One representative strain of subclade I, LSUCC0096, had extensive halotolerance and a mesophilic temperature range for growth, with a maximum rate of 0.36 doublings/h at 35°C. Cells were curved rod/spirillum-shaped, ∼1.5 by 0.2 μm. Growth yield on thiosulfate as the sole electron donor under autotrophic conditions was roughly one-third that of heterotrophic growth, even though calculations indicated similar Gibbs energies for both catabolisms. These phenotypic data show that some " Halomarinus" organisms can switch between serving as carbon sources or sinks and indicate the likely anabolic cost of lithoautotrophic growth. Our results thus provide new hypotheses about the roles of these organisms in global biogeochemical cycling of carbon and sulfur. Marine microbial communities are teeming with understudied taxa due to the sheer numbers of species in any given sample of seawater. One group, the OM252 clade of , has been identified in gene surveys from myriad locations, and one isolated organism has even been genome sequenced (HIMB30). However, further study of these organisms has not occurred. Using another isolated representative (strain LSUCC0096) and publicly available genome sequences from metagenomic and single-cell genomic data sets, we examined the diversity within the OM252 clade and the distribution of these taxa in the world's oceans, reconstructed the predicted metabolism of the group, and quantified growth dynamics in LSUCC0096. Our results generate new knowledge about the previously enigmatic OM252 clade and point toward the importance of facultative chemolithoautotrophy for supporting some clades of ostensibly "heterotrophic" taxa.
PubMed: 34184914
DOI: 10.1128/mSystems.00276-21 -
Journal of Bacteriology Oct 2015Current knowledge regarding the mechanism that governs flagellar motor rotation in response to environmental stimuli stems mainly from the study of monotrichous and...
UNLABELLED
Current knowledge regarding the mechanism that governs flagellar motor rotation in response to environmental stimuli stems mainly from the study of monotrichous and peritrichous bacteria. Little is known about how two polar flagella, one at each cell pole of the so-called amphitrichous bacterium, are coordinated to steer the swimming. Here we fluorescently labeled the flagella of Magnetospirillum magneticum AMB-1 cells and took advantage of the magnetically controllable swimming of this bacterium to investigate flagellar rotation in moving cells. We identified three motility behaviors (runs, tumbles, and reversals) and two characteristic fluorescence patterns likely corresponding to flagella rotating in opposite directions. Each AMB-1 locomotion mode was systematically associated with particular flagellar patterns at the poles which led us to conclude that, while cell runs are allowed by the asymmetrical rotation of flagellar motors, their symmetrical rotation triggers cell tumbling. Our observations point toward a precise coordination of the two flagellar motors which can be temporarily unsynchronized during tumbling.
IMPORTANCE
Motility is essential for bacteria to search for optimal niches and survive. Many bacteria use one or several flagella to explore their environment. The mechanism by which bipolarly flagellated cells coordinate flagellar rotation is poorly understood. We took advantage of the genetic amenability and magnetically controlled swimming of the spirillum-shaped magnetotactic bacterium Magnetospirillum magneticum AMB-1 to correlate cell motion with flagellar rotation. We found that asymmetric rotation of the flagella (counterclockwise at the lagging pole and clockwise at the leading pole) enables cell runs whereas symmetric rotation triggers cell tumbling. Taking into consideration similar observations in spirochetes, bacteria possessing bipolar ribbons of periplasmic flagella, we propose a conserved motility paradigm for spirillum-shaped bipolarly flagellated bacteria.
Topics: Flagella; Magnetic Fields; Magnetospirillum; Movement
PubMed: 26240070
DOI: 10.1128/JB.00172-15 -
Biophysical Journal Nov 1972The hydromechanics of spirilla locomotion is analyzed by considering the balance of both rectilinear and angular momenta of the surrounding viscous fluid which is...
The hydromechanics of spirilla locomotion is analyzed by considering the balance of both rectilinear and angular momenta of the surrounding viscous fluid which is otherwise at rest. The physical model of Spirillum adopted for the present analysis consists of a rigid helical body with flagella attached to both ends of the helix. The motion is supposed to be activated first by the polar flagella, both rotating in the same sense, thus causing the helical body to rotate in the opposite sense in angular recoil, which in turn pushes the body forward in response to the balance of linear momentum of the surrounding fluid. The sweeping back of the polar flagella during forward motion is ascribed to a certain bending flexibility of the flagella and of their conjunction with the body. Based on this model some quantitative results for Spirillum movement are predicted, and are found to be consistent with existing experimental data.
Topics: Cell Movement; Flagella; Mathematics; Models, Biological; Spirillum
PubMed: 4642227
DOI: 10.1016/S0006-3495(72)86181-2 -
Nutrients Nov 2021(1) Background: Our previous study found that the dietary fiber supplement in patients with hypertension increased SCFA-producers, Bififidobacterium and Spirillum in the...
(1) Background: Our previous study found that the dietary fiber supplement in patients with hypertension increased SCFA-producers, Bififidobacterium and Spirillum in the gut microbiota, which may be associated with improvement of depression and anxiety through the gut-brain axis. However, only a few studies have explored the association between dietary fiber intake (DFI) and the incidence of depression and anxiety in hypertensive patients. (2) Methods: A cross-sectional survey was conducted in one comprehensive hospital and one community clinic aimed at understanding the status of DFI and the association between DFI and incidences of depression and anxiety in hypertensive patients. Levels of DFI were obtained through a two-24 h diet recall. According to the levels of DFI from low to high, the participants were divided into Q1, Q2, Q3 and Q4 groups. The Reported Outcomes Measurement Information System short form v1.0-Depression 8b and Anxiety 8a were used to assess patients' levels of depression and anxiety. (3) Results: A total of 459 hypertensive patients were recruited and the daily DFI was 10.4 g. The incidences of hypertension combined with depression and anxiety were 19.6% and 18.5%, respectively. Regression analysis showed statistically significant associations between DFI and depression (B = -0.346, = 0.001) and anxiety score (B = -0.565, < 0.001). In logistic regression, after the covariates were adjusted, DFI was associated with the incidence of depression in Q3 (OR 2.641, 95% CI 1.050-6.640) and with that of anxiety in Q1 (OR 2.757, 95% CI 1.035-7.346), compared with Q4. (4) Conclusions: A higher consumption of DF was a protective factor for depression and anxiety in hypertensive patients.
Topics: Adult; Aged; Aged, 80 and over; Anxiety; Brain-Gut Axis; Cross-Sectional Studies; Depression; Diet; Diet Surveys; Dietary Fiber; Eating; Essential Hypertension; Female; Humans; Incidence; Male; Middle Aged; Regression Analysis; Young Adult
PubMed: 34836414
DOI: 10.3390/nu13114159 -
Applied and Environmental Microbiology Nov 2021Magnetotactic bacteria (MTB) are prokaryotes that form intracellular magnetite (FeO) or greigite (FeS) nanocrystals with tailored sizes, often in chain configurations....
Magnetotactic bacteria (MTB) are prokaryotes that form intracellular magnetite (FeO) or greigite (FeS) nanocrystals with tailored sizes, often in chain configurations. Such magnetic particles are each surrounded by a lipid bilayer membrane, called a magnetosome, and provide a model system for studying the formation and function of specialized internal structures in prokaryotes. Using fluorescence-coupled scanning electron microscopy, we identified a novel magnetotactic spirillum, XQGS-1, from freshwater Xingqinggong Lake, Xi'an City, Shaanxi Province, China. Phylogenetic analyses based on 16S rRNA gene sequences indicate that strain XQGS-1 represents a novel genus of the class in the phylum. Transmission electron microscopy analyses reveal that strain XQGS-1 forms on average 17 ± 3 magnetite magnetosome particles with an ideal truncated octahedral morphology, with an average length and width of 88.3 ± 11.7 nm and 83.3 ± 11.0 nm, respectively. They are tightly organized into a single chain along the cell long axis close to the concave side of the cell. Intrachain magnetic interactions likely result in these large equidimensional magnetite crystals behaving as magnetically stable single-domain particles that enable bacterial magnetotaxis. Combined structural and chemical analyses demonstrate that XQGS-1 cells also biomineralize intracellular amorphous calcium phosphate (2 to 3 granules per cell; 90.5- ± 19.3-nm average size) and weakly crystalline calcium carbonate (2 to 3 granules per cell; 100.4- ± 21.4-nm average size) in addition to magnetite. Our results expand the taxonomic diversity of MTB and provide evidence for intracellular calcium phosphate biomineralization in MTB. Biomineralization is a widespread process in eukaryotes that form shells, teeth, or bones. It also occurs commonly in prokaryotes, resulting in more than 60 known minerals formed by different bacteria under wide-ranging conditions. Among them, magnetotactic bacteria (MTB) are remarkable because they might represent the earliest organisms that biomineralize intracellular magnetic iron minerals (i.e., magnetite [FeO] or greigite [FeS]). Here, we report a novel magnetotactic spirillum (XQGS-1) that is phylogenetically affiliated with the class. In addition to magnetite crystals, XQGS-1 cells form intracellular submicrometer calcium carbonate and calcium phosphate granules. This finding supports the view that MTB are also an important microbial group for intracellular calcium carbonate and calcium phosphate biomineralization.
Topics: Alphaproteobacteria; Calcium; Calcium Carbonate; Calcium Phosphates; China; Ferrosoferric Oxide; Lakes; Phylogeny; RNA, Ribosomal, 16S
PubMed: 34756060
DOI: 10.1128/AEM.01556-21 -
Autopsy & Case Reports 2023Endocarditis is a rare, often fatal complication of rat bite fever caused by . Only 39 cases have been reported (including this case) as of 2022. We describe a case and...
INTRODUCTION
Endocarditis is a rare, often fatal complication of rat bite fever caused by . Only 39 cases have been reported (including this case) as of 2022. We describe a case and aim to perform this entit's first systematic literature review.
METHODS
We performed a systematic review in CENTRAL, EMBASE, MEDLINE, SciELO, and LILACS. The terms used were terms used were (but not limited to) rat bite fever, , and endocarditis. We included all abstracts and articles with patients with echocardiographic or histologic-proven endocarditis. In case of discordance, a third reviewer was involved. Our protocol was submitted to PROSPERO (CRD42022334092). We also performed searches for studies on the reference list of included articles.
RESULTS
We retrieved 108 and included 36 abstracts and articles. A total of 39 patients (including our report) were identified. The mean age was 41.27, and 61.5% were males. The most common findings were fever, murmur, arthralgias, fatigue, splenomegaly, and rash. Underlying heart disease was present in 33%. Exposure to rats was noted in 71.8% of patients, with 56.4% recalling a rat bite. Anemia was seen in 57%, leukocytosis in 52%, and elevated inflammatory markers in 58% that had lab work performed. The mitral valve was most affected, followed by the aortic, tricuspid, and pulmonary valves. Surgical intervention was required in 14 (36%) cases. Of those, 10 required valve replacement. Death was reported in 36% of cases. Unfortunately, the literature available is limited to case series and reports.
CONCLUSION
Our review allows clinicians to suspect better, diagnose, and manage Streptobacillary endocarditis.
PubMed: 37101553
DOI: 10.4322/acr.2023.423 -
Journal of Bacteriology Nov 1967Spirillum itersonii contains b- and c-type cytochromes as well as a carbon monoxide-binding pigment of the cytochrome o type. Synthesis of cytochromes b and c is...
Spirillum itersonii contains b- and c-type cytochromes as well as a carbon monoxide-binding pigment of the cytochrome o type. Synthesis of cytochromes b and c is increased by about two- and fourfold, respectively, when cells are transferred from high to low aeration. The increased concentration of cytochrome is not accompanied by an increase in the respiration rate of the cells. Both cytochrome b and cytochrome c are located in the particulate fraction of cells grown under high or low aeration, and both pigments are fully reducible by succinate. No evidence was found for the accumulation of the protein component of either cytochrome when synthesis of the prosthetic group was limited by iron deficiency, nor did heme or precursors accumulate when protein synthesis was prevented. It was therefore concluded that the formation of the heme prosthetic group is closely integrated with the synthesis of the protein moiety. delta-Aminolevulinate synthase was detected in extracts of the organism. Its activity was correlated with cytochrome synthesis; it was reduced by high aeration and increased under low aeration. The synthase was inhibited by hemin at concentrations of 10 mum or higher. The observations are consistent with a central role for the heme prosthetic group in the regulation of cytochrome synthesis.
Topics: Bacterial Proteins; Carbon Monoxide; Chloramphenicol; Culture Media; Cytochromes; Electron Transport; Heme; Iron; Lyases; Nitrates; Oxygen; Oxygen Consumption; Pigments, Biological; Spectrum Analysis; Spirillum; Succinates
PubMed: 6057811
DOI: 10.1128/jb.94.5.1648-1655.1967 -
Journal of Bacteriology Mar 1980The ultrastructure of a magnetotactic bacterium (strain MS-1) was examined by transmission, scanning, and scanning-transmission electron microscopy. The organism...
The ultrastructure of a magnetotactic bacterium (strain MS-1) was examined by transmission, scanning, and scanning-transmission electron microscopy. The organism resembled other spirilla in general cell morphology, although some differences were detected at the ultrastructural level. Electron-dense particles within magnetotactic cells were shown by energy-dispersive X-ray analysis to be localizations containing iron. A non-magnetotactic variant of strain MS-1 lacked these novel bacterial inclusion bodies. A chain of these particles traversed each magnetotactic cell in a specific arrangement that was consistent from cell to cell, seemingly associated with the inner surface of the cytoplasmic membrane. Each particle was surrounded by an electron-dense layer separated from the particle surface by an electron-transparent region. The term "magnetosome" is proposed for the electron-dense particles with their enveloping layer(s) as found in this and other magnetotactic bacteria.
Topics: Cell Membrane; Cell Nucleus; Cell Wall; Cytoplasm; Flagella; Inclusion Bodies; Magnetics; Microscopy, Electron; Organoids; Ribosomes; Spirillum
PubMed: 6245069
DOI: 10.1128/jb.141.3.1399-1408.1980