scholarly journals Effective extracellular expression in Bacillus subtilis of thermostable Geobacillus stearothermophilus lipase

2021 ◽  
Author(s):  
Elemosho Ridwan ◽  
Antonius Suwanto ◽  
Maggy Thenawidjaja
Keyword(s):  
Bacillus Subtilis ◽  
Geobacillus Stearothermophilus ◽  
Extracellular Expression

Extracellular expression of agarase rAgaM1 in Bacillus subtilis and its ability for neoagaro-oligosaccharide production

2019 ◽  
Vol 59 (4) ◽  
pp. 359-367 ◽  
Author(s):  
Li Li ◽  
Wu Qu ◽  
Min Jin ◽  
Wenjie Di ◽  
Runying Zeng
Keyword(s):  
Bacillus Subtilis ◽  
Extracellular Expression

scholarly journals Effect of Pasteurized Low Acidic Indigenous Beverages Produced in Northern Cameroon on Germination of Bacillus and Geobacillus Spores Species

2021 ◽  
Vol 8 (2) ◽  
pp. 52-62
Author(s):  
James Ronald Bayoï ◽  
François-Xavier Etoa
Keyword(s):  
Bacillus Subtilis ◽  
Incubation Time ◽  
Spore Germination ◽  
Inhibitory Effect ◽  
Geobacillus Stearothermophilus ◽  
Northern Cameroon ◽  
Natural Preservatives ◽  
Acidic Beverages ◽  
Good Hygiene ◽  
Spore Forming Bacteria

The present study aimed to investigate the influence of three commercially available traditional acidic beverages on spore germination. “Foléré”, red “té” and white “mpedli” sorghum beers have been produced at the laboratory scale assisted by experimented producers, and pH of samples were adjusted at 2.01, 2.63 and 2.8 respectively, then they were pasteurized. The samples produced were tested on four spore-forming bacteria (Bacillus cereus, Bacillus megapterium, Bacillus subtilis and Geobacillus stearothermophilus) and germination was assessed both on culture plate media and by loss of optical density (OD) methods. The results obtained showed that “foléré” at pH 2.01, and both indigenous sorghum red beer at pH 2.63 and white beer at pH 2.8 were effective on spore germination, and efficacy significantly increase (p < 0.05) with the incubation time. The presence of alcohol in the pasteurized white (2.43 %) and red (4.7 %) sorghum beers has significantly (p < 0.05) improved the anti-germinating activity compared to the non-alcoholic “foléré” beverage. The sensitivity of B. cereus and B. subtilis was positively and significantly correlated (r = 0.880; p < 0.01) likewise the sensitivity of B. megapterium and G. stearothermophilus (r = 0.725; p < 0.05), and the activity of traditional white and red sorghum beers was found to be very significant (p < 0.05) for each couple respectively. The loss of OD showed an inhibitory effect of indigenous beverages germination and exhibited a microcycle on all tested spore-forming bacteria. It was concluded that if the good hygiene and manufacturing practices were applied for production of indigenous beverages, they might easily be used as natural preservatives and for prevention of gastroenteritis induced by germination and outgrowth of spore-forming bacteria like B. cereus.

PTS-Mediated Regulation of the Transcription Activator MtlR from Different Species: Surprising Differences despite Strong Sequence Conservation

2015 ◽  
Vol 25 (2-3) ◽  
pp. 94-105 ◽  
Author(s):  
Philippe Joyet ◽  
Meriem Derkaoui ◽  
Houda Bouraoui ◽  
Josef Deutscher
Keyword(s):  
Bacillus Subtilis ◽  
Lactobacillus Casei ◽  
Sequence Conservation ◽  
Geobacillus Stearothermophilus ◽  
Transcription Activator ◽  
Phosphotransferase System ◽  
Transcription Regulator ◽  
Regulatory Domains ◽  
Genes Encoding ◽  
Enzyme I

The hexitol <smlcap>D</smlcap>-mannitol is transported by many bacteria via a phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS). In most Firmicutes, the transcription activator MtlR controls the expression of the genes encoding the <smlcap>D</smlcap>-mannitol-specific PTS components and <smlcap>D</smlcap>-mannitol-1-P dehydrogenase. MtlR contains an N-terminal helix-turn-helix motif followed by an Mga-like domain, two PTS regulation domains (PRDs), an EIIB<sup>Gat</sup>- and an EIIA<sup>Mtl</sup>-like domain. The four regulatory domains are the target of phosphorylation by PTS components. Despite strong sequence conservation, the mechanisms controlling the activity of MtlR from <i>Lactobacillus casei</i>, <i>Bacillus subtilis</i> and <i>Geobacillus stearothermophilus</i> are quite different. Owing to the presence of a tyrosine in place of the second conserved histidine (His) in PRD2, <i>L. casei</i> MtlR is not phosphorylated by Enzyme I (EI) and HPr. When the corresponding His in PRD2 of MtlR from <i>B. subtilis</i> and <i>G. stearothermophilus</i> was replaced with alanine, the transcription regulator was no longer phosphorylated and remained inactive. Surprisingly, <i>L. casei</i> MtlR functions without phosphorylation in PRD2 because in a <i>ptsI</i> (EI) mutant MtlR is constitutively active. EI inactivation prevents not only phosphorylation of HPr, but also of the PTS<sup>Mtl</sup> components, which inactivate MtlR by phosphorylating its EIIB<sup>Gat</sup>- or EIIA<sup>Mtl</sup>-like domain. This explains the constitutive phenotype of the <i>ptsI</i> mutant. The absence of EIIB<sup>Mtl</sup>-mediated phosphorylation leads to induction of the <i>L. casei</i><i>mtl </i>operon. This mechanism resembles <i>mtlARFD</i> induction in <i>G. stearothermophilus</i>, but differs from EIIA<sup>Mtl</sup>-mediated induction in <i>B. subtilis</i>. In contrast to <i>B. subtilis</i> MtlR, <i>L. casei</i> MtlR activation does not require sequestration to the membrane via the unphosphorylated EIIB<sup>Mtl</sup> domain.

scholarly journals A microbiological multi-plate method to detect cephalosporin residues in milk

2020 ◽  
Vol 89 (2) ◽  
pp. 201-208
Author(s):  
Pavlína Navrátilová ◽  
Jana Vyhnálková ◽  
Hana Zachovalová ◽  
Lenka Vorlová
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Diffusion Method ◽  
Geobacillus Stearothermophilus ◽  
Detection Capability ◽  
Plate Method ◽  
Maximum Residue Limits ◽  
The Individual ◽  
Kocuria Rhizophila

The aim of this study was to determine the detection capability (CCβ) of a multi-plate diffusion method for selected cephalosporins for which the maximum residue limits (MRLs) in milk have been set (ceftiofur, cefoperazone, cephalexine, cephazoline, cephalonium, cephapirine, cefquinome). The multiplate method was composed of Bacillus subtilis BGA CCM 4062 plates (agar pH of 6, 8 and 7.2); Kocuria rhizophila CCM 552 plate, Geobacillus stearothermophilus CCM 5965 plate and Escherichia coli CCM 7372 plate. Geobacillus stearothermophilus plate showed the highest sensitivity. CCβ for the tested cephalosporins was determined at MRLs or lower, except for cefquinome, which was undetectable even at 12 × the MRL. Kocuria rhizophila plate showed the highest sensitivity to ceftiofur (CCβ = 100 μg/l); cephazoline and cephalonium could not be detected even at 12 × times the MRL. Escherichia coli plate was most sensitive to cefoperazone (CCβ = 60 μg/l). Other than cephapirine, none of the cephalosporins could be detected by B. subtilis BGA (pH 6, 8 and 7.2) plates even at 12 × the MRL. Our results demonstrate the differences in sensitivity to selected cephalosporins of the individual plate methods that together form the multi-plate method. The multi-plate method is sensitive enough to detect most of the tested cephalosporins, with the exception of cefquinome, which could not be detected at levels close to MRL.

Decontamination of Sugar Syrup by Pulsed Light

2012 ◽  
Vol 75 (5) ◽  
pp. 913-917 ◽  
Author(s):  
ALINE CHAINE ◽  
CAROLINE LEVY ◽  
BERNARD LACOUR ◽  
CHRISTOPHE RIEDEL ◽  
FRÉDÉRIC CARLIN
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Bacillus Subtilis ◽  
Aspergillus Niger ◽  
Flow Rate ◽  
Light Treatment ◽  
Geobacillus Stearothermophilus ◽  
Pulsed Light ◽  
Log Reduction ◽  
Sugar Syrup ◽  
Xenon Flash

The pulsed light produced by xenon flash lamps was applied to 65 to 67 °Brix sugar syrups artificially contaminated with suspensions of Saccharomyces cerevisiae and with spores of Bacillus subtilis, Geobacillus stearothermophilus, Alicyclobacillus acidoterrestris, and Aspergillus niger. The emitted pulsed light contained 18.5% UV radiation. At least 3-log reductions of S. cerevisiae, B. subtilis, G. stearothermophilus, and A. acidoterrestris suspended in 3-mm-deep volumes of sugar syrup were obtained with a fluence of the incident pulsed light equal to or less than 1.8 J/cm2, and the same results were obtained for B. subtilis and A. acidoterrestris suspended in 10-mm-deep volumes of sugar syrup. A. niger spores would require a more intense treatment; for instance, the maximal log reduction was close to 1 with a fluence of the incident pulsed light of 1.2 J/cm2. A flowthrough reactor with a flow rate of 320 ml/min and a flow gap of 2.15 mm was designed for pulsed light treatment of sugar syrup. Using this device, a 3-log reduction of A. acidoterrestris spores was obtained with 3 to 4 pulses of incident pulsed light at 0.91 J/cm2 per sugar syrup volume.

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