Bacillus subtilis Intraspecies Interactions Shape Probiotic Activity Against Salmonella Typhimurium.

Commercial probiotics are often formulated as multi-strain cocktails, but the effects of social interactions, particularly between strains of a species, are often neglected, despite their potential to contribute to higher-order interactions where these interactions could affect those with a third party. In this study, we investigated the probiotic potential of a collection of Bacillus subtilis strains against Salmonella Typhimurium in single-strain and mixed cultures. The results indicate a promising probiotic potential of B.

Nonkin interactions between Bacillus subtilis soil isolates limit the spread of swarming deficient cheats.

Cooperative behaviours in human, animal, and even microbial societies are vulnerable to exploitation. Kin discrimination has been hypothesized to help stabilize cooperation. However, the mechanisms that sustain cooperative behaviour remain poorly understood.

Reduction of hexavalent chromium using bacterial isolates and a microbial community enriched from tannery effluent.

We investigated microbial growth in increasing concentrations of hexavalent chromium (Cr(VI)) and its reduction by a microbial community enriched from tannery effluent and by the bacterial strains isolated from the enriched community. The bacterial growth was monitored by measuring the optical cell density (OD), while the Cr(VI) concentration in the samples was determined using spectrophotometry and liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). At a Cr(VI) concentration of 100 mg/L, the isolates affiliated with Pseudomonas aeruginosa (P.

Kin Discrimination Modifies Strain Distribution, Spatial Segregation, and Incorporation of Extracellular Matrix Polysaccharide Mutants of Bacillus subtilis Strains into Mixed Floating Biofilms.

Microorganisms in nature form multicellular groups called biofilms. In biofilms, bacteria embedded in the extracellular matrix (ECM) interact intensely due to their proximity. Most studies have investigated genetically homogeneous biofilms, leaving a gap in knowledge on genetically heterogeneous biofilms.

Kin discrimination drives territorial exclusion during Bacillus subtilis swarming and restrains exploitation of surfactin.

Swarming is the collective movement of bacteria across a surface. It requires the production of surfactants (public goods) to overcome surface tension and provides an excellent model to investigate bacterial cooperation. Previously, we correlated swarm interaction phenotypes with kin discrimination between B.

Kin discrimination promotes horizontal gene transfer between unrelated strains in Bacillus subtilis.

Bacillus subtilis is a soil bacterium that is competent for natural transformation. Genetically distinct B. subtilis swarms form a boundary upon encounter, resulting in killing of one of the strains.

Influence of Diclofenac on Activated Sludge Bacterial Communities in Fed-Batch Reactors.

Research Background: The occurrence and environmental toxicity of pharmaceuticals have recently attracted increasing attention. Diclofenac is a highly consumed non-steroidal anti-inflammatory drug, which is often detected in wastewaters, but investigations of its influence on bacteria are scarce.

Experimental Approach: We investigated the influence of this pharmaceutical on bacterial community in activated sludge exposed to increasing concentrations of diclofenac in fed-batch reactors over 41 days.

A Combinatorial Kin Discrimination System in Bacillus subtilis.

Multicellularity inherently involves a number of cooperative behaviors that are potentially susceptible to exploitation but can be protected by mechanisms such as kin discrimination. Discrimination of kin from non-kin has been observed in swarms of the bacterium Bacillus subtilis, but the underlying molecular mechanism has been unknown. We used genetic, transcriptomic, and bioinformatic analyses to uncover kin recognition factors in this organism.

Kin discrimination between sympatric Bacillus subtilis isolates.

Kin discrimination, broadly defined as differential treatment of conspecifics according to their relatedness, could help biological systems direct cooperative behavior toward their relatives. Here we investigated the ability of the soil bacterium Bacillus subtilis to discriminate kin from nonkin in the context of swarming, a cooperative multicellular behavior. We tested a collection of sympatric conspecifics from soil in pairwise combinations and found that despite their history of coexistence, the vast majority formed distinct boundaries when the swarms met.

Effect of Low-Density Static Magnetic Field on the Oxidation of Ammonium by and by Activated Sludge in Municipal Wastewater.

Ammonium removal is a key step in biological wastewater treatment and novel approaches that improve this process are in great demand. The aim of this study is to test the hypothesis that ammonium removal from wastewater can be stimulated by static magnetic fields. This was achieved by analysis of the effects of static magnetic field (SMF) on the growth and activity of , a key ammonia-oxidising bacterium, where increased growth and increased ammonia oxidation rate were detected when bacteria were exposed to SMF at 17 mT.

Effects of low-density static magnetic fields on the growth and activities of wastewater bacteria Escherichia coli and Pseudomonas putida.

The aim of this study was to explore the influence of a moderate static magnetic field (SMF) of different densities on Escherichia coli and Pseudomonas putida that are commonly found in wastewater treatment plants. In line with literature reports that SMF increases the efficiency of wastewater treatment the findings of this study indicated that SMF negatively influenced the growth but positively influenced the enzymatic activities and ATP levels of the two model bacteria. The inhibitory effect of SMF on growth of E.

Total bacterial and ammonia-oxidizer community structure in moving bed biofilm reactors treating municipal wastewater and inorganic synthetic wastewater.

Industrial-scale bioreactors treat wastewater of temporally variable composition under different weather conditions, while the microbial populations of wastewater treatment plants are often studied in controlled laboratory-scale systems with defined influent at a constant temperature. 16S rRNA- and ammonia oxidising amoA-gene-defined bacterial community structure was investigated in industrial and laboratory-scale moving bed biofilm bioreactors (MBBRs) treating municipal wastewater (WW) or synthetic ammonium solution (AS). Nitrification activity, 16S rRNA and amoA gene T-RFLP profiles were comparable between industrial and laboratory scale WW bioreactors.

Nitrification activity and community structure of nitrite-oxidizing bacteria in the bioreactors operated with addition of pharmaceuticals.

Pharmaceuticals represent a group of the new emerging contaminants, which might influence microbial communities in the activated sludge. Nitrification activity and Nitrospira community structure in the small-scale reactors supplied with different concentrations (0, 50, 200, 500 μg L(-1)) of the selected pharmaceuticals (ibuprofen, naproxen, ketoprofen, diclofenac and clofibric acid) were evaluated. Ammonia removal was not influenced by selected pharmaceuticals.

Influence of pharmaceutical residues on the structure of activated sludge bacterial communities in wastewater treatment bioreactors.

Concern is growing over contamination of the environment with pharmaceuticals because of their widespread use and incomplete removal during wastewater treatment, where microorganisms drive the key processes. The influence of pharmaceuticals on bacterial community structure in activated sludge was assessed in small-scale wastewater treatment bioreactors containing different concentrations (5, 50, 200 and 500microgL(-1)) of several commonly used pharmaceuticals (ibuprofen, naproxen, ketoprofen, diclofenac and clofibric acid). T-RFLP analyses of the bacterial 16S rRNA genes indicated a minor but consistent shift in the bacterial community structure in the bioreactor R50 supplied with pharmaceuticals at a concentration of 50microgL(-1), compared to the control reactor R0, which was operated without addition of pharmaceuticals.

The Rok protein of Bacillus subtilis represses genes for cell surface and extracellular functions.

Rok is a repressor of the transcriptional activator ComK and is therefore an important regulator of competence in Bacillus subtilis (T. T. Hoa, P.