Impact of temperature and oxygen on the fate of Bacillus weihenstephanensis in a food-based medium

ABSTRACT We used multilocus sequence typing (MLST) to characterize phylogenetic relationships for a collection of Bacillus cereus group strains isolated from forest soil in the Paris area during a mild winter. This collection contains multiple strains isolated from the same soil sample and strains isolated from samples from different sites. We characterized 115 strains of this collection and 19 other strains based on the sequences of the clpC, dinB, gdpD, panC, purF, and yhfL loci. The number of alleles ranged from 36 to 53, and a total of 93 allelic profiles or sequence types were distinguished. We identified three major strain clusters—C, T, and W—based on the comparison of individual gene sequences or concatenated sequences. Some less representative clusters and subclusters were also distinguished. Analysis of the MLST data using the concept of clonal complexes led to the identification of two, five, and three such groups in clusters C, T, and W, respectively. Some of the forest isolates were closely related to independently isolated psychrotrophic strains. Systematic testing of the strains of this collection showed that almost all the strains that were able to grow at a low temperature (6°C) belonged to cluster W. Most of these strains, including three independently isolated strains, belong to two clonal complexes and are therefore very closely related genetically. These clonal complexes represent strains corresponding to the previously identified species Bacillus weihenstephanensis. Most of the other strains of our collection, including some from the W cluster, are not psychrotrophic. B. weihenstephanensis (cluster W) strains appear to comprise an effectively sexual population, whereas Bacillus thuringiensis (cluster T) and B. cereus (cluster C) have clonal population structures.

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Isolation and characterization of heavy metal tolerant Gram-positive bacteria with bioremedial properties from municipal waste rich soil of Kestopur canal (Kolkata), West Bengal, India

Biologia ◽

10.2478/s11756-012-0099-5 ◽

2012 ◽

Vol 67 (5) ◽

Cited By ~ 20

Author(s):

Kamala Gupta ◽

Chitrita Chatterjee ◽

Bhaskar Gupta

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Metal Tolerance ◽

Environmental Pollutants ◽

Heavy Metal Tolerance ◽

Antibiotic Sensitivity ◽

Bacterial Strains ◽

High Concentration ◽

Isolation And Characterization ◽

Bacillus Weihenstephanensis

AbstractThe present study was conducted to determine the culturable bacterial profile from Kestopur canal (Kolkata, India) and analyze their heavy metal tolerance. In addition to daily sewage including solid and soluble wastes, a considerable load of toxic metals are released into this water body from industries, tanneries and agriculture, household as well as health sectors. Screening out microbes from such an environment was done keeping in mind their multifunctional application especially for bioremediation. Heavy metals are major environmental pollutants when present in high concentration in soil and show potential toxic effects on growth and development in plants and animals. Some edible herbs growing in the canal vicinity, and consumed by people, were found to harbour these heavy metals at sub-toxic levels. The bioconcentration factor of these plants being <1 indicates that they probably only absorb but not accumulate heavy metals. All the thirteen Grampositive bacteria isolated from these plants rhizosphere were found to tolerate high concentration of heavy metals like Co, Ni, Pb, Cr, Fe. Phylogenetic analysis of their 16S rDNA genes revealed that they belonged to one main taxonomic group — the Firmicutes. Seven of them were found to be novel with 92–95% sequence homology with known bacterial strains. Further microbiological analyses show that the alkaliphilic Bacillus weihenstephanensis strain IA1 and Exiguobacterium aestuarii strain CE1, with selective antibiotic sensitivity along with high Ni2+ and Cr6+ removal capabilities, respectively, can be prospective candidates for bioremediation.

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Effect of Imidacloprid on Bacterial Soil Isolate Bacillus weihenstephanensis

Insecticides Resistance ◽

10.5772/61503 ◽

2016 ◽

Author(s):

A.A. Shetti ◽

B.B. Kaliwal

Keyword(s):

Bacillus Weihenstephanensis ◽

Soil Isolate

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Detection and Identification of Bacillus cereus, Bacillus cytotoxicus, Bacillus thuringiensis, Bacillus mycoides and Bacillus weihenstephanensis via Machine Learning Based FTIR Spectroscopy

Frontiers in Microbiology ◽

10.3389/fmicb.2019.00902 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 12

Author(s):

Murat Bağcıoğlu ◽

Martina Fricker ◽

Sophia Johler ◽

Monika Ehling-Schulz

Keyword(s):

Machine Learning ◽

Bacillus Thuringiensis ◽

Bacillus Cereus ◽

Ftir Spectroscopy ◽

Bacillus Mycoides ◽

Detection And Identification ◽

Bacillus Weihenstephanensis

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Suboptimal Bacillus licheniformis and Bacillus weihenstephanensis Spore Incubation Conditions Increase Heterogeneity of Spore Outgrowth Time

Applied and Environmental Microbiology ◽

10.1128/aem.02061-19 ◽

2020 ◽

Vol 86 (6) ◽

Author(s):

C. Trunet ◽

N. Mtimet ◽

A.-G. Mathot ◽

F. Postollec ◽

I. Leguerinel ◽

...

Keyword(s):

Heat Treatment ◽

Flow Cytometry ◽

Bacillus Licheniformis ◽

Model Parameters ◽

Vegetative Cells ◽

Content Type ◽

Bacillus Weihenstephanensis ◽

Spore Outgrowth ◽

Growth Limits ◽

Kinetics Of

ABSTRACT Changes with time of a population of Bacillus weihenstephanensis KBAB4 and Bacillus licheniformis AD978 dormant spores into germinated spores and vegetative cells were followed by flow cytometry, at pH ranges of 4.7 to 7.4 and temperatures of 10°C to 37°C for B. weihenstephanensis and 18°C to 59°C for B. licheniformis. Incubation conditions lower than optimal temperatures or pH led to lower proportions of dormant spores able to germinate and extended time of germination, a lower proportion of germinated spores able to outgrow, an extension of their times of outgrowth, and an increase of the heterogeneity of spore outgrowth time. A model based on the strain growth limits was proposed to quantify the impact of incubation temperature and pH on the passage through each physiological stage. The heat treatment temperature or time acted independently on spore recovery. Indeed, a treatment at 85°C for 12 min or at 95°C for 2 min did not have the same impact on spore germination and outgrowth kinetics of B. weihenstephanensis despite the fact that they both led to a 10-fold reduction of the population. Moreover, acidic sporulation pH increased the time of outgrowth 1.2-fold and lowered the proportion of spores able to germinate and outgrow 1.4-fold. Interestingly, we showed by proteomic analysis that some proteins involved in germination and outgrowth were detected at a lower abundance in spores produced at pH 5.5 than in those produced at pH 7.0, maybe at the origin of germination and outgrowth behavior of spores produced at suboptimal pH. IMPORTANCE Sporulation and incubation conditions have an impact on the numbers of spores able to recover after exposure to sublethal heat treatment. Using flow cytometry, we were able to follow at a single-cell level the changes in the physiological states of heat-stressed spores of Bacillus spp. and to discriminate between dormant spores, germinated spores, and outgrowing vegetative cells. We developed original mathematical models that describe (i) the changes with time of the proportion of cells in their different states during germination and outgrowth and (ii) the influence of temperature and pH on the kinetics of spore recovery using the growth limits of the tested strains as model parameters. We think that these models better predict spore recovery after a sublethal heat treatment, a common situation in food processing and a concern for food preservation and safety.

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