Fungal mycelia and bacterial thiamine establish a mutualistic growth mechanism

Exclusivity in physical spaces and nutrients is a prerequisite for survival of organisms, but a few species have been able to develop mutually beneficial strategies that allow them to co-habit. Here, we discovered a mutualistic mechanism between filamentous fungus, Aspergillus nidulans, and bacterium, Bacillus subtilis. The bacterial cells co-cultured with the fungus traveled along mycelia using their flagella and dispersed farther with the expansion of fungal colony, indicating that the fungal mycelia supply space for bacteria to migrate, disperse, and proliferate. Transcriptomic, genetic, molecular mass, and imaging analyses demonstrated that the bacteria reached the mycelial edge and supplied thiamine to the growing hyphae, which led to a promotion of hyphal growth. The thiamine transfer from bacteria to the thiamine non-auxotrophic fungus was directly demonstrated by stable isotope labeling. The simultaneous spatial and metabolic interactions demonstrated in this study reveal a mutualism that facilitates the communicating fungal and bacterial species to obtain an environmental niche and nutrient, respectively.

Download Full-text

Retarded swarming motility in Bacillus subtilis NRS-762 and Pseudomonas aeruginosa PRD-10

10.7287/peerj.preprints.26914 ◽

2018 ◽

Author(s):

Wenfa Ng

Keyword(s):

Pseudomonas Aeruginosa ◽

Bacillus Subtilis ◽

Bacterial Species ◽

Nutritional Stress ◽

Cellular Level ◽

Bacterial Cells ◽

Loss Of Function ◽

Swarming Motility ◽

Bacteria Growth ◽

Solid Media

Coping with nutritional stress is essential for cell survival, of which many strategies at the cellular level lend support for ensuring the survival of the population at a particular habitat. One postulated mechanism is swarming motility in bacterial cells, where, upon depletion of nutrients at a locale, cells would coordinate their movement, synthesize more flagella, and secrete lubricants for moving rapidly across surfaces in search for food. Known to engage in swarming motility, Bacillus subtilis and Pseudomonas aeruginosa are two common bacterial species with versatile metabolism that use the motility mode to colonize new habitats with more favourable environmental and nutritional conditions. However, experimental observations of bacteria growth on a variety of agar media revealed that B. subtilis NRS-762 (ATCC 8473) and P. aeruginosa PRD-10 (ATCC 15442) exhibited retarded swarming motility upon entry into stationary phase on solid media. Specifically, B. subtilis NRS-762 colonies exhibited round, wrinkled morphologies compared to complex filamented swarming patterns common in strains able to engage in swarming motility. On the other hand, P. aeruginosa PRD-10 colonies were round, mucoid, and expanded outwards from the colony centre without extending filaments from the centre; thereby, indicating retarded swarming motility. Thus, impaired cellular machinery for swarming motility or mutated and deleted genes likely account for observed retarded swarming motility in B. subtilis NRS-762 and P. aeruginosa PRD-10. More importantly, observations of small filaments extending radially from an expanded colony of P. aeruginosa PRD-10 grown on minimal salts medium supplemented with yeast extract highlighted possible loss of function of effector molecules that transmit cellular decision at swarming motility into movement, while sensory mechanisms feeding into the motility mechanism remained intact. More broadly, observations of impaired swarming motility in B. subtilis NRS-762 and P. aeruginosa PRD-10 in two species otherwise endowed with the motility mode highlighted that additional triggers for swarming motility are likely present, and the motility mode may have been evolutionary selected for other functions in addition to foraging for food in times of nutritional stress.

Download Full-text

Inactivation and Ultrastructure Analysis ofBacillus spp. andClostridium perfringensSpores

Microscopy and Microanalysis ◽

10.1017/s1431927613013949 ◽

2014 ◽

Vol 20 (1) ◽

pp. 238-244 ◽

Cited By ~ 2

Author(s):

Christine A. Brantner ◽

Ryan M. Hannah ◽

James P. Burans ◽

Robert K. Pope

Keyword(s):

Electron Microscopy ◽

Bacillus Subtilis ◽

Bacillus Thuringiensis ◽

Environmental Factors ◽

Prolonged Exposure ◽

Bacterial Species ◽

Temperature Extremes ◽

Bacterial Cells ◽

Bacterial Endospores ◽

Time Required

AbstractBacterial endospores are resistant to many environmental factors from temperature extremes to ultraviolet irradiation and are generally more difficult to inactivate or kill than vegetative bacterial cells. It is often considered necessary to treat spores or samples containing spores with chemical fixative solutions for prolonged periods of time (e.g., 1–21 days) to achieve fixation/inactivation to enable electron microscopy (EM) examination outside of containment laboratories. Prolonged exposure to chemical fixatives, however, can alter the ultrastructure of spores for EM analyses. This study was undertaken to determine the minimum amount of time required to inactivate/sterilize and fix spore preparations from several bacterial species using a universal fixative solution for EM that maintains the ultrastructural integrity of the spores. We show that a solution of 4% paraformaldehyde with 1% glutaraldehyde inactivated spore preparations ofBacillus anthracis,Bacillus cereus,Bacillus megaterium,Bacillus thuringiensis, andClostridium perfringensin 30 min, andBacillus subtilisin 240 min. These results suggest that this fixative solution can be used to inactivate and fix spores from several major groups of bacterial spore formers after 240 min, enabling the fixed preparations to be removed from biocontainment and safely analyzed by EM outside of biocontainment.

Download Full-text

Retarded swarming motility in Bacillus subtilis NRS-762 and Pseudomonas aeruginosa PRD-10

10.7287/peerj.preprints.26914v1 ◽

2018 ◽

Author(s):

Wenfa Ng

Keyword(s):

Pseudomonas Aeruginosa ◽

Bacillus Subtilis ◽

Bacterial Species ◽

Nutritional Stress ◽

Cellular Level ◽

Bacterial Cells ◽

Loss Of Function ◽

Swarming Motility ◽

Bacteria Growth ◽

Solid Media

Coping with nutritional stress is essential for cell survival, of which many strategies at the cellular level lend support for ensuring the survival of the population at a particular habitat. One postulated mechanism is swarming motility in bacterial cells, where, upon depletion of nutrients at a locale, cells would coordinate their movement, synthesize more flagella, and secrete lubricants for moving rapidly across surfaces in search for food. Known to engage in swarming motility, Bacillus subtilis and Pseudomonas aeruginosa are two common bacterial species with versatile metabolism that use the motility mode to colonize new habitats with more favourable environmental and nutritional conditions. However, experimental observations of bacteria growth on a variety of agar media revealed that B. subtilis NRS-762 (ATCC 8473) and P. aeruginosa PRD-10 (ATCC 15442) exhibited retarded swarming motility upon entry into stationary phase on solid media. Specifically, B. subtilis NRS-762 colonies exhibited round, wrinkled morphologies compared to complex filamented swarming patterns common in strains able to engage in swarming motility. On the other hand, P. aeruginosa PRD-10 colonies were round, mucoid, and expanded outwards from the colony centre without extending filaments from the centre; thereby, indicating retarded swarming motility. Thus, impaired cellular machinery for swarming motility or mutated and deleted genes likely account for observed retarded swarming motility in B. subtilis NRS-762 and P. aeruginosa PRD-10. More importantly, observations of small filaments extending radially from an expanded colony of P. aeruginosa PRD-10 grown on minimal salts medium supplemented with yeast extract highlighted possible loss of function of effector molecules that transmit cellular decision at swarming motility into movement, while sensory mechanisms feeding into the motility mechanism remained intact. More broadly, observations of impaired swarming motility in B. subtilis NRS-762 and P. aeruginosa PRD-10 in two species otherwise endowed with the motility mode highlighted that additional triggers for swarming motility are likely present, and the motility mode may have been evolutionary selected for other functions in addition to foraging for food in times of nutritional stress.

Download Full-text

Modulation of Gut Microbiota through Dietary Phytochemicals as a Novel Anti-infective Strategy

Current Drug Discovery Technologies ◽

10.2174/1570163816666191107124214 ◽

2020 ◽

Vol 17 (4) ◽

pp. 498-506 ◽

Cited By ~ 2

Author(s):

Pavan K. Mujawdiya ◽

Suman Kapur

Keyword(s):

Microbial Community ◽

Quorum Sensing ◽

Population Density ◽

Gut Microbiota ◽

Biofilm Formation ◽

Chemical Interaction ◽

Bacterial Species ◽

Critical Role ◽

Bacterial Cells ◽

Gut Microbes

: Quorum Sensing (QS) is a phenomenon in which bacterial cells communicate with each other with the help of several low molecular weight compounds. QS is largely dependent on population density, and it triggers when the concentration of quorum sensing molecules accumulate in the environment and crosses a particular threshold. Once a certain population density is achieved and the concentration of molecules crosses a threshold, the bacterial cells show a collective behavior in response to various chemical stimuli referred to as “auto-inducers”. The QS signaling is crucial for several phenotypic characteristics responsible for bacterial survival such as motility, virulence, and biofilm formation. Biofilm formation is also responsible for making bacterial cells resistant to antibiotics. : The human gut is home to trillions of bacterial cells collectively called “gut microbiota” or “gut microbes”. Gut microbes are a consortium of more than 15,000 bacterial species and play a very crucial role in several body functions such as metabolism, development and maturation of the immune system, and the synthesis of several essential vitamins. Due to its critical role in shaping human survival and its modulating impact on body metabolisms, the gut microbial community has been referred to as “the forgotten organ” by O`Hara et al. (2006) [1]. Several studies have demonstrated that chemical interaction between the members of bacterial cells in the gut is responsible for shaping the overall microbial community. : Recent advances in phytochemical research have generated a lot of interest in finding new, effective, and safer alternatives to modern chemical-based medicines. In the context of antimicrobial research various plant extracts have been identified with Quorum Sensing Inhibitory (QSI) activities among bacterial cells. This review focuses on the mechanism of quorum sensing and quorum sensing inhibitors isolated from natural sources.

Download Full-text

Effects of the Chromosome Partitioning Protein Spo0J (ParB) on oriC Positioning and Replication Initiation in Bacillus subtilis

Journal of Bacteriology ◽

10.1128/jb.185.4.1326-1337.2003 ◽

2003 ◽

Vol 185 (4) ◽

pp. 1326-1337 ◽

Cited By ~ 79

Author(s):

Philina S. Lee ◽

Daniel Chi-Hong Lin ◽

Shigeki Moriya ◽

Alan D. Grossman

Keyword(s):

Bacillus Subtilis ◽

Binding Sites ◽

Fluorescent Protein ◽

Bacterial Species ◽

Significant Proportion ◽

Subcellular Location ◽

Replication Initiation ◽

Null Mutant ◽

Protein Ratio ◽

Chromosome Partitioning

ABSTRACT Spo0J (ParB) of Bacillus subtilis is a DNA-binding protein that belongs to a conserved family of proteins required for efficient plasmid and chromosome partitioning in many bacterial species. We found that Spo0J contributes to the positioning of the chromosomal oriC region, but probably not by recruiting the origin regions to specific subcellular locations. In wild-type cells during exponential growth, duplicated origin regions were generally positioned around the cell quarters. In a spo0J null mutant, sister origin regions were often closer together, nearer to midcell. We found, by using a Spo0J-green fluorescent protein [GFP] fusion, that the subcellular location of Spo0J was a consequence of the chromosomal positions of the Spo0J binding sites. When an array of binding sites (parS sites) were inserted at various chromosomal locations in the absence of six of the eight known parS sites, Spo0J-GFP was no longer found predominantly at the cell quarters, indicating that Spo0J is not sufficient to recruit chromosomal parS sites to the cell quarters. spo0J also affected chromosome positioning during sporulation. A spo0J null mutant showed an increase in the number of cells with some origin-distal regions located in the forespore. In addition, a spo0J null mutation caused an increase in the number of foci per cell of LacI-GFP bound to arrays of lac operators inserted in various positions in the chromosome, including the origin region, an increase in the DNA-protein ratio, and an increase in origins per cell, as determined by flow cytometry. These results indicate that the spo0J mutant produced a significant proportion of cells with increased chromosome content, probably due to increased and asynchronous initiation of DNA replication.

Download Full-text

Bacteria in the global atmosphere – Part 2: Modeling of emissions and transport between different ecosystems

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-9281-2009 ◽

2009 ◽

Vol 9 (23) ◽

pp. 9281-9297 ◽

Cited By ~ 190

Author(s):

S. M. Burrows ◽

T. Butler ◽

P. Jöckel ◽

H. Tost ◽

A. Kerkweg ◽

...

Keyword(s):

Seasonal Variation ◽

Residence Time ◽

General Circulation ◽

Bacterial Species ◽

Circulation Model ◽

Cloud Condensation Nucleus ◽

Cloud Formation ◽

Emission Region ◽

Culturable Bacteria ◽

Bacterial Cells

Abstract. Bacteria are constantly being transported through the atmosphere, which may have implications for human health, agriculture, cloud formation, and the dispersal of bacterial species. We simulate the global transport of bacteria, represented as 1 μm and 3 μm diameter spherical solid particle tracers in a general circulation model. We investigate factors influencing residence time and distribution of the particles, including emission region, cloud condensation nucleus activity and removal by ice-phase precipitation. The global distribution depends strongly on the assumptions made about uptake into cloud droplets and ice. The transport is also affected, to a lesser extent, by the emission region, particulate diameter, and season. We find that the seasonal variation in atmospheric residence time is insufficient to explain by itself the observed seasonal variation in concentrations of particulate airborne culturable bacteria, indicating that this variability is mainly driven by seasonal variations in culturability and/or emission strength. We examine the potential for exchange of bacteria between ecosystems and obtain rough estimates of the flux from each ecosystem by using a maximum likelihood estimation technique, together with a new compilation of available observations described in a companion paper. Globally, we estimate the total emissions of bacteria-containing particles to the atmosphere to be 7.6×1023–3.5×1024 a−1, originating mainly from grasslands, shrubs and crops. We estimate the mass of emitted bacteria- to be 40–1800 Gg a−1, depending on the mass fraction of bacterial cells in the particles. In order to improve understanding of this topic, more measurements of the bacterial content of the air and of the rate of surface-atmosphere exchange of bacteria will be necessary. Future observations in wetlands, hot deserts, tundra, remote glacial and coastal regions and over oceans will be of particular interest.

Download Full-text

Lysis and biological control of Aspergillus niger by Bacillus subtilis AF 1

Canadian Journal of Microbiology ◽

10.1139/m96-072 ◽

1996 ◽

Vol 42 (6) ◽

pp. 533-538 ◽

Cited By ~ 64

Author(s):

A. R. Podile ◽

A. P. Prakash

Keyword(s):

Biological Control ◽

Bacillus Subtilis ◽

Aspergillus Niger ◽

Fungal Growth ◽

Dry Weight ◽

Crown Rot ◽

Fungal Mycelium ◽

Infested Soil ◽

Dual Culture ◽

Bacterial Cells

A biocontrol rhizobacterial strain of Bacillus subtilis AF 1 grown for 6 h was coinoculated with Aspergillus niger at different time intervals and microscopic observations revealed adherence of bacterial cells to the fungal mycelium. Bacterial cells multiplied in situ and colonized the mycelial surface. Growth of AF 1 resulted in damage to the cell wall, followed by lysis. AF 1 inoculation into media containing A. niger at 0, 6, and 12 h suppressed >90% fungal growth, while in 18- and 24-h cultures fungal growth inhibition was 70 and 56%, respectively, in terms of dry weight. In dual culture the fungal growth was not accompanied by formation of spores. The mycelial preparation of A. niger as principal carbon source supported the growth of B. subtilis, as much as chitin. Extracellular protein precipitate from B. subtilis culture filtrate had a significant growth-retarding effect on A. niger. Groundnut seeds bacterized with B. subtilis showed a reduced incidence of crown rot in A. niger infested soil, suggesting a possible role of B. subtilis in biological control of A. niger.Key words: mycolytic bacteria, Bacillus subtilis, Aspergillus niger, biological control.

Download Full-text

Microbial Photoinactivation by Visible Light Results in Limited Loss of Membrane Integrity

Antibiotics ◽

10.3390/antibiotics10030341 ◽

2021 ◽

Vol 10 (3) ◽

pp. 341

Author(s):

Katharina Hoenes ◽

Richard Bauer ◽

Barbara Spellerberg ◽

Martin Hessling

Keyword(s):

Visible Light ◽

Pseudomonas Fluorescens ◽

Bacterial Cell ◽

Bacterial Species ◽

Membrane Integrity ◽

Cell Lysis ◽

Microbial Inactivation ◽

Bacterial Cells ◽

Resistance Development ◽

Transmission Electron

Interest in visible light irradiation as a microbial inactivation method has widely increased due to multiple possible applications. Resistance development is considered unlikely, because of the multi-target mechanism, based on the induction of reactive oxygen species by wavelength specific photosensitizers. However, the affected targets are still not completely identified. We investigated membrane integrity with the fluorescence staining kit LIVE/DEAD® BacLight™ on a Gram positive and a Gram negative bacterial species, irradiating Staphylococcus carnosus and Pseudomonas fluorescens with 405 nm and 450 nm. To exclude the generation of viable but nonculturable (VBNC) bacterial cells, we applied an ATP test, measuring the loss of vitality. Pronounced uptake of propidium iodide was only observed in Pseudomonas fluorescens at 405 nm. Transmission electron micrographs revealed no obvious differences between irradiated samples and controls, especially no indication of an increased bacterial cell lysis could be observed. Based on our results and previous literature, we suggest that visible light photoinactivation does not lead to rapid bacterial cell lysis or disruption. However, functional loss of membrane integrity due to depolarization or inactivation of membrane proteins may occur. Decomposition of the bacterial envelope following cell death might be responsible for observations of intracellular component leakage.

Download Full-text

Toxicity of the First Ten MEIC Chemicals to Bacteria

Alternatives to Laboratory Animals ◽

10.1177/026119299302100205 ◽

1993 ◽

Vol 21 (2) ◽

pp. 151-155

Author(s):

Gustaw Kerszman

Keyword(s):

Escherichia Coli ◽

Bacillus Subtilis ◽

Linear Regression ◽

Minimal Inhibitory Concentration ◽

Blood Concentration ◽

Inhibitory Concentration ◽

Human Lymphocytes ◽

Bacterial Species ◽

E Coli ◽

Mild Toxicity

The toxicity of the first ten MEIC chemicals to Escherichia coli and Bacillus subtilis was examined. Nine of the chemicals were toxic to the bacteria, with the minimal inhibitory concentration (MIC) ranging from 10-3 to 4.4M. The sensitivities of both organisms were similar, but the effect on E. coli was often bactericidal, while it was bacteriostatic for B. subtilis. Digoxin was not detectably toxic to either bacterial species. Amitriptyline and FeSO4 were relatively less toxic to the bacteria than to human cells. For seven chemicals, a highly significant linear regression was established between log MIC in bacteria and log of blood concentration, giving lethal and moderate/mild toxicity in humans, as well as with toxicity to human lymphocytes.

Download Full-text