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Nature Communications Mar 2021Long-distance extracellular electron transfer has been observed in Gram-negative bacteria and plays roles in both natural and engineering processes. The electron...
Long-distance extracellular electron transfer has been observed in Gram-negative bacteria and plays roles in both natural and engineering processes. The electron transfer can be mediated by conductive protein appendages (in short unicellular bacteria such as Geobacter species) or by conductive cell envelopes (in filamentous multicellular cable bacteria). Here we show that Lysinibacillus varians GY32, a filamentous unicellular Gram-positive bacterium, is capable of bidirectional extracellular electron transfer. In microbial fuel cells, L. varians can form centimetre-range conductive cellular networks and, when grown on graphite electrodes, the cells can reach a remarkable length of 1.08 mm. Atomic force microscopy and microelectrode analyses suggest that the conductivity is linked to pili-like protein appendages. Our results show that long-distance electron transfer is not limited to Gram-negative bacteria.
Topics: Bacillaceae; Bioelectric Energy Sources; Electric Conductivity; Electrodes; Electron Transport; Fimbriae, Bacterial; Gram-Positive Bacteria; Graphite; Microscopy, Atomic Force; Nanowires
PubMed: 33731718
DOI: 10.1038/s41467-021-21709-z -
Microbial Biotechnology Mar 2021The potential advantages for fermentation production of chemicals at high temperatures are attractive, such as promoting the rate of biochemical reactions, reducing the...
The potential advantages for fermentation production of chemicals at high temperatures are attractive, such as promoting the rate of biochemical reactions, reducing the risk of contamination and the energy consumption for fermenter cooling. In this work, we de novo engineered the thermophile Geobacillus thermoglucosidasius to produce riboflavin, since this bacterium can ferment diverse carbohydrates at an optimal temperature of 60°C with a high growth rate. We first introduced a heterogeneous riboflavin biosynthetic gene cluster and enabled the strain to produce detectable riboflavin (28.7 mg l ). Then, with the aid of an improved gene replacement method, we preformed metabolic engineering in this strain, including replacement of ribC with a mutant allele to weaken the consumption of riboflavin, manipulation of purine pathway to enhance precursor supply, deletion of ccpN to tune central carbon catabolism towards riboflavin production and elimination of the lactate dehydrogenase gene to block the dominating product lactic acid. Finally, the engineered strain could produce riboflavin with the titre of 1034.5 mg l after 12-h fermentation in a mineral salt medium, indicating G. thermoglucosidasius is a promising host to develop high-temperature cell factory of riboflavin production. This is the first demonstration of riboflavin production in thermophilic bacteria at an elevated temperature.
Topics: Bacillaceae; Fermentation; Geobacillus; Metabolic Engineering; Riboflavin
PubMed: 32096925
DOI: 10.1111/1751-7915.13543 -
Laeknabladid Mar 2022The bacterial genus Bacillus is widely distributed environmentally and is usually considered a low-virulence organism, except for B. anthracis. A blood culture positive...
INTRODUCTION
The bacterial genus Bacillus is widely distributed environmentally and is usually considered a low-virulence organism, except for B. anthracis. A blood culture positive for Bacillus is often looked at as contamination. Nevertheless, B. cereus can cause invasive infections in humans and produces harmful toxins. The epidemiology of these infections remains poorly studied.
MATERIAL AND METHODS
All possible invasive infections caused by Bacillus during 2006-2018 at Landspitali University Hospital were identified from culture results. Clinical information was used to evaluate if there was a possible infection or confirmed infection. Here, the authors propose and use clinical criteria to categorize each case as contamination, possible infection or confirmed infection. The incidence of possible or confirmed infections was calculated using hospital catchment population data.
RESULTS
Positive cultures of Bacillus sp. from sterile sites during 2006-2018 were identified from 126 patients; blood (116), synovial fluid (8) and cerebrospinal fluid (2). In total, 26 cases were confirmed infection (20.6%), 10 possible infection (7.9%) and 90 contamination (71.4%). The incidence was 1.4 cases/100.000 inhabitants/year. Injection drug use was a risk factor among 11/26 patients with confirmed infection. The most common clinical presentation was sepsis. In this study, Bacillus was resistant to beta-lactam antibiotics in 92% of confirmed infections and 66% of the cases considered contamination (p=0.02).
CONCLUSION
Positive blood cultures of Bacillus sp. should be taken seriously, especially among patients with injection drug use, malignancy or immunocompromised state. It is important to draw two sets of blood cultures if there is a real suspicion of an infection to establish diagnosis and avoid unnecessary antibiotic therapy.
Topics: Anti-Bacterial Agents; Bacillus; Bacillus anthracis; Bacillus cereus; Humans; Iceland
PubMed: 35230258
DOI: 10.17992/lbl.2022.03.681 -
Microbiology (Reading, England) Jan 2014The genus Geobacillus comprises endospore-forming obligate thermophiles. These bacteria have been isolated from cool soils and even cold ocean sediments in anomalously... (Review)
Review
The genus Geobacillus comprises endospore-forming obligate thermophiles. These bacteria have been isolated from cool soils and even cold ocean sediments in anomalously high numbers, given that the ambient temperatures are significantly below their minimum requirement for growth. Geobacilli are active in environments such as hot plant composts, however, and examination of their genome sequences reveals that they are endowed with a battery of sensors, transporters and enzymes dedicated to hydrolysing plant polysaccharides. Although they appear to be relatively minor members of the plant biomass-degrading microbial community, Geobacillus bacteria have achieved a significant population with a worldwide distribution, probably in large part due to adaptive features of their spores. First, their morphology and resistance properties enable them to be mobilized in the atmosphere and transported long distances. Second, their longevity, which in theory may be extreme, enables them to lie quiescent but viable for long periods of time, accumulating gradually over time to achieve surprisingly high population densities.
Topics: Environmental Microbiology; Geobacillus; Microbial Viability; Temperature
PubMed: 24085838
DOI: 10.1099/mic.0.071696-0 -
MSphere Apr 2021The exosporium is the outermost spore layer of some and species and related organisms. It mediates the interactions of spores with their environment, modulates spore...
The exosporium is the outermost spore layer of some and species and related organisms. It mediates the interactions of spores with their environment, modulates spore adhesion and germination, and has been implicated in pathogenesis. In , the exosporium consists of a crystalline basal layer, formed mainly by the two cysteine-rich proteins CotY and ExsY, surrounded by a hairy nap composed of glycoproteins. The morphogenetic protein CotE is necessary for the integrity of the exosporium, but how CotE directs exosporium assembly remains unknown. Here, we used super-resolution fluorescence microscopy to follow the localization of SNAP-tagged CotE, CotY, and ExsY during sporulation and evidenced the interdependencies among these proteins. Complexes of CotE, CotY, and ExsY are present at all sporulation stages, and the three proteins follow similar localization patterns during endospore formation that are reminiscent of the localization pattern of CotE. We show that CotE guides the formation of one cap at both forespore poles by positioning CotY and then guides forespore encasement by ExsY, thereby promoting exosporium elongation. By these two actions, CotE ensures the formation of a complete exosporium. Importantly, we demonstrate that the assembly of the exosporium is not a unidirectional process, as previously proposed, but occurs through the formation of two caps, as observed during coat morphogenesis, suggesting that a general principle governs the assembly of the spore surface layers of Spores of are enveloped in an outermost glycoprotein layer. In the group, encompassing the and pathogens, this layer is easily recognizable by a characteristic balloon-like appearance and separation from the underlying coat by an interspace. In spite of its importance for the environmental interactions of spores, including those with host cells, the mechanism of assembly of the exosporium is poorly understood. We used super-resolution fluorescence microscopy to directly visualize the formation of the exosporium during the sporulation of , and we studied the localization and interdependencies of proteins essential for exosporium morphogenesis. We discovered that these proteins form a morphogenetic scaffold before a complete exosporium or coat is detectable. We describe how the different proteins localize to the scaffold and how they subsequently assemble around the spore, and we present a model for the assembly of the exosporium.
Topics: Bacillus cereus; Bacterial Proteins; Microscopy, Fluorescence; Spores, Bacterial
PubMed: 33883264
DOI: 10.1128/mSphere.00007-21 -
Journal of Microbiological Methods Nov 2022Parageobacillus thermoglucosidasius is a promising chassis for producing chemicals and fuels. Here we designed, built and tested the pMTL60000 modular plasmids...
Parageobacillus thermoglucosidasius is a promising chassis for producing chemicals and fuels. Here we designed, built and tested the pMTL60000 modular plasmids containing standardised Gram-positive and Gram-negative replicons, selectable markers and application-specific modules. The pMTL60000 modular plasmids were characterised with regard to transformation efficiency, segregational stability, copy number and compatibility.
Topics: Genetic Vectors; Plasmids; Bacillaceae; Replicon
PubMed: 36241006
DOI: 10.1016/j.mimet.2022.106600 -
Journal of Clinical Microbiology Dec 2020The objective of this study was to construct a rapid, high-throughput, and biosafety-compatible screening method for and based on matrix-assisted laser desorption...
Novel Strategy for Rapidly and Safely Distinguishing Bacillus anthracis and Bacillus cereus by Use of Peptide Mass Fingerprints Based on Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.
The objective of this study was to construct a rapid, high-throughput, and biosafety-compatible screening method for and based on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). MALDI-TOF MS coupled to ClinProTools was used to discover MALDI-TOF MS biomarker peaks and generate a classification model based on a genetic algorithm (GA) to differentiate between different and isolates. Thirty and 19 strains were used to construct and analyze the model, and 40 strains were used for validation. For the GA screening model, the cross-validation values, which reflect the ability of the model to handle variability among the test spectra, and the recognition capability values, which reflect the model's ability to correctly identify its component spectra, were all 100%. This model contained 10 biomarker peaks ( 3,339.9, 3,396.3, 3,682.4, 5,476.7, 6,610.6, 6,680.1, 7,365.3, 7,792.4, 9,475.8, and 10,934.1) used to correctly identify 28 and 12 isolates from 40 isolates, with a sensitivity and specificity of 100%. With the obvious advantages of being rapid, highly accurate, and highly sensitive and having a low cost and high throughput, MALDI-TOF MS ClinProTools is a powerful and reliable tool for screening and strains.
Topics: Bacillus; Bacillus anthracis; Bacillus cereus; Humans; Peptides; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 33115846
DOI: 10.1128/JCM.02358-20 -
Microbiology Spectrum Feb 2016The three main species of the Bacillus cereus sensu lato, B. cereus, B. thuringiensis, and B. anthracis, were recognized and established by the early 1900 s because they...
The three main species of the Bacillus cereus sensu lato, B. cereus, B. thuringiensis, and B. anthracis, were recognized and established by the early 1900 s because they each exhibited distinct phenotypic traits. B. thuringiensis isolates and their parasporal crystal proteins have long been established as a natural pesticide and insect pathogen. B. anthracis, the etiological agent for anthrax, was used by Robert Koch in the 19th century as a model to develop the germ theory of disease, and B. cereus, a common soil organism, is also an occasional opportunistic pathogen of humans. In addition to these three historical species designations, are three less-recognized and -understood species: B. mycoides, B. weihenstephanensis, and B. pseudomycoides. All of these "species" combined comprise the Bacillus cereus sensu lato group. Despite these apparently clear phenotypic definitions, early molecular approaches to separate the first three by various DNA hybridization and 16S/23S ribosomal sequence analyses led to some "confusion" because there were limited differences to differentiate between these species. These and other results have led to frequent suggestions that a taxonomic change was warranted to reclassify this group to a single species. But the pathogenic properties of B. anthracis and the biopesticide applications of B. thuringiensis appear to "have outweighed pure taxonomic considerations" and the separate species categories are still being maintained. B. cereus sensu lato represents a classic example of a now common bacterial species taxonomic quandary.
Topics: Bacillus anthracis; Bacillus cereus; Bacillus thuringiensis; Humans; Phylogeny
PubMed: 26999390
DOI: 10.1128/microbiolspec.TBS-0012-2012 -
FEMS Microbiology Ecology Jun 2013Bacillus cereus comprises a highly versatile group of bacteria, which are of particular interest because of their capacity to cause disease. Emetic food poisoning is... (Review)
Review
Bacillus cereus comprises a highly versatile group of bacteria, which are of particular interest because of their capacity to cause disease. Emetic food poisoning is caused by the toxin cereulide produced during the growth of emetic B. cereus in food, while diarrhoeal food poisoning is the result of enterotoxin production by viable vegetative B. cereus cells in the small intestine, probably in the mucus layer and/or attached to the host's intestinal epithelium. The numbers of B. cereus causing disease are highly variable, depending on diverse factors linked to the host (age, diet, physiology and immunology), bacteria (cellular form, toxin genes and expression) and food (nutritional composition and meal characteristics). Bacillus cereus group strains show impressive ecological diversity, ranging from their saprophytic life cycle in soil to symbiotic (commensal and mutualistic) lifestyles near plant roots and in guts of insects and mammals to various pathogenic ones in diverse insect and mammalian hosts. During all these different ecological lifestyles, their toxins play important roles ranging from providing competitive advantages within microbial communities to inhibition of specific pathogenic organisms for their host and accomplishment of infections by damaging their host's tissues.
Topics: Animals; Bacillaceae Infections; Bacillus; Bacillus cereus; Bacterial Toxins; Diarrhea; Ecosystem; Emetics; Enterotoxins; Food Microbiology; Foodborne Diseases; Humans; Microbial Interactions; Phylogeny
PubMed: 23488744
DOI: 10.1111/1574-6941.12110 -
Journal of Hazardous Materials Feb 2021With the number of easily accessible ores depleting, alternate primary and secondary sources are required to meet the increasing demand of economically important metals....
With the number of easily accessible ores depleting, alternate primary and secondary sources are required to meet the increasing demand of economically important metals. Whilst highly abundant, these materials are of lower grade with respect to traditional ores, thus highly selective and sustainable metal extraction technologies are needed to reduce processing costs. Here, we investigated the metal leaching potential of biogenic ammonia produced by a ureolytic strain of Lysinibacillus sphaericus on eight primary and secondary materials, comprised of mining and metallurgical residues, sludges and automotive shredder residues (ASR). For the majority of materials, moderate to high yields (30-70%) and very high selectivity (>97% against iron) of copper and zinc were obtained with 1 mol L total ammonia. Optimal leaching was achieved and further refined for the ASR in a two-step indirect leaching system with biogenic ammonia. Copper leaching was the result of local corrosion and differences in leaching against the synthetic (NH)CO control could be accounted for by pH shifts from microbial metabolism, subsequently altering free NH required for coordination. These results provide important findings for future sustainable metal recovery technologies from secondary materials.
Topics: Ammonia; Bacillaceae; Copper; Minerals; Zinc
PubMed: 33264923
DOI: 10.1016/j.jhazmat.2020.123842