Criteria for screening probiotics such as bile tolerance and resistance to acids were studied with 13 spore-forming lactic acid producing bacteria. Different strains of
Sporolactobacillus,
Bacillus ...laevolacticus,
Bacillus racemilacticus and
Bacillus coagulans grown in MRS broth were subjected to low pH conditions (2, 2.5 and 3) and increasing bile concentrations. Among these microorganisms,
Bacillus laevolacticus DSM 6475 and all
Sporolactobacillus strains tested except
Sporolactobacillus racemicus IAM 12395, were resistant to pH 3. Only
Bacillus racemilacticus and
Bacillus coagulans strains were tolerant to bile concentrations over 0.3% (w/v).
A protease‐sensitive antibacterial substance produced by Bacillus coagulans I4 strain, isolated from cattle faeces, was classified as a bacteriocin‐like inhibitory substance and named coagulin. The ...inhibitory spectrum included B. coagulans and unrelated bacteria such as Enterococcus, Leuconostoc, Oenococcus, Listeria and Pediococcus. Coagulin was stable at 60 °C for 90 min, at a pH ranging from 4 to 8 and appeared to be unaffected by α‐amylase, lipase or organic solvents (10% v/v). Coagulin exhibited a bactericidal and a bacteriolytic mode of action against indicator cells. The apparent molecular mass was estimated to be about 3–4 kDa by SDS‐PAGE. The B. coagulans I4 strain harbours a plasmid, pI4, approximately 14 kb in size. Novobiocin curing experiments yielded two derivatives that no longer produced the bacteriocin‐like inhibitory substance. Plasmid content of these two derivatives showed that one had lost pI4,whereas the second harboured a deleted form of this plasmid, thus suggesting a plasmid location for the genes for coagulin production.
ABSTRACT
A plasmid-linked antimicrobial peptide, named coagulin, produced by
Bacillus coagulans
I
4
has recently been reported (B. Hyronimus, C. Le Marrec and M. C. Urdaci, J. Appl. Microbiol. ...85:42–50, 1998). In the present study, the complete, unambiguous primary amino acid sequence of the peptide was obtained by a combination of both N-terminal sequencing of purified peptide and the complete sequence deduced from the structural gene harbored by plasmid I
4
. Data revealed that this peptide of 44 residues has an amino acid sequence similar to that described for pediocins AcH and PA-1, produced by different
Pediococcus acidilactici
strains and 100% identical. Coagulin and pediocin differed only by a single amino acid at their C terminus. Analysis of the genetic determinants revealed the presence, on the pI
4
DNA, of the entire 3.5-kb operon of four genes described for pediocin AcH and PA-1 production. No extended homology was observed between pSMB74 from
P. acidilactici
and pI
4
when analyzing the regions upstream and downstream of the operon. An oppositely oriented gene immediately dowstream of the bacteriocin operon specifies a 474-amino-acid protein which shows homology to Mob-Pre (plasmid recombination enzyme) proteins encoded by several small plasmids extracted from gram-positive bacteria. This is the first report of a pediocin-like peptide appearing naturally in a non-lactic acid bacterium genus.
The Multi-sensor Airborne Radiation Survey (MARS) instrument Fast, J.E.; Aalseth, C.E.; Asner, D.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2013, Letnik:
698
Journal Article
Recenzirano
The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gama ray spectrometers that achieves the high ...detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications, including airborne and maritime operations.
Historically, large germanium arrays for field applications have consisted of multiple detectors each housed in their own cryostat. In order to ruggedize the detectors for field use these cryostats ...have had additional support material introduced that significantly impacted cryogenic performance. This paper presents the development of a new cryostat design suitable for deployment of ~10 kg of high purity germanium detectors that achieves outstanding cryogenic performance (~5 W at 80 K) while providing the high detection efficiency required for stand-off measurements and the ruggedization required for use in a variety of field applications.
On-Site Inspection (OSI) is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclide isotopes created by an underground nuclear ...explosion are a valuable signature of a Treaty violation. Argon-37 is produced by neutron interaction with calcium in soil, super(40)Ca(n,alpha) super(37)Ar. For OSI, the 35-day half-life of super(37)Ar provides both high specific activity and sufficient time for completion of an inspection before decay limits sensitivity. This paper presents a low-background internal-source gas proportional counter with an super(37)Ar measurement sensitivity level equivalent to 45 mBq/SCM in wholeair.
The MAJORANA Project Elliott, S R; Aalseth, C E; Akashi-Ronquest, M ...
Journal of physics. Conference series,
06/2009, Letnik:
173, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Building a Ovββ experiment with the ability to probe neutrino mass in the inverted hierarchy region requires the combination of a large detector mass sensitive to Ovββ, on the order of 1-tonne, and ...unprecedented background levels, on the order of or less than 1 count per year in the Ovβ β signal region. The MAJORANA Collaboration proposes a design based on using high-purity enriched 76Ge crystals deployed in ultralow background electroformed Cu cryostats and using modern analysis techniques that should be capable of reaching the required sensitivity while also being scalable to a 1-tonne size. To demonstrate feasibility, the collaboration plans to construct a prototype system, the MAJORANA DEMONSTRATOR, consisting of 30 kg of 86% enriched 76Ge detectors and 30 kg of natural or isotope-76-depleted Ge detectors. We plan to deploy and evaluate two different Ge detector technologies, one based on a p-type configuration and the other on n-type.
On-Site Inspection (OSI) is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclide isotopes created by an underground nuclear ...explosion are a valuable signature of a Treaty violation. Argon-37 is produced from neutron interaction with calcium in soil, 40Ca(n,{\alpha})37Ar. For OSI, the 35-day half-life of 37Ar provides both high specific activity and sufficient time for completion of an inspection before decay limits sensitivity. This paper presents a low-background internal-source gas proportional counter with an 37Ar measurement sensitivity level equivalent to 45.1 mBq/SCM in whole air.
A protease-sensitive antibacterial substance produced by Bacillus coagulans I4 strain, isolated from cattle faeces, was classified as a bacteriocin-like inhibitory substance and named coagulin. The ...inhibitory spectrum included B. coagulans and unrelated bacteria such as Enterococcus, Leuconostoc, Oenococcus, Listeria and Pediococcus. Coagulin was stable at 60 degrees C for 90 min, at a pH ranging from 4 to 8 and appeared to be unaffected by alpha-amylase, lipase or organic solvents (10% v/v). Coagulin exhibited a bactericidal and a bacteriolytic mode of action against indicator cells. The apparent molecular mass was estimated to be about 3-4 kDa by SDS-PAGE. The B. coagulans I4 strain harbours a plasmid, pI4, approximately 14 kb in size. Novobiocin curing experiments yielded two derivatives that no longer produced the bacteriocin-like inhibitory substance. Plasmid content of these two derivatives showed that one had lost pI4, whereas the second harboured a deleted form of this plasmid, thus suggesting a plasmid location for the genes for coagulin production.
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