Biocontrol science

Publisher: Nihon Bōkin Bōbai Gakkai

Description

Impact factor 1.31

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    Impact factor
  • 5-year impact
    0.00
  • Cited half-life
    4.70
  • Immediacy index
    0.08
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  • Website
    Biocontrol Science website
  • Other titles
    Biocontrol science
  • ISSN
    1342-4815
  • OCLC
    37579252
  • Material type
    Periodical
  • Document type
    Journal / Magazine / Newspaper

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel competition model developed with the new logistic model and the Lotka-Volterra model successfully predicted the growth of bacteria in mixed culture using the mesophiles Staphylococcus aureus, Escherichia coli, and Salmonella at a constant temperature in our previous studies. In this study, we further studied the prediction of the growth of those bacteria in mixed culture at dynamic temperatures with various initial populations with the competition model. First, we studied the growth kinetics of the species in a monoculture at various constant temperatures ranging from 16℃ to 32℃. With the analyzed data in the monoculture, we then examined the prediction of bacterial growth in mixed culture with two and three species. The growth of the bacteria in the mixed culture at dynamic temperatures was successfully predicted with the model. The residuals between the observed and predicted populations at the data points were <0.5 log at most points, being 83.3% and 84.2% for the two-species mixture and the three-species mixture, respectively. The present study showed that the model could be applied to the competitive growth in mixed culture at dynamic temperature patterns.
    Biocontrol science 01/2014; 19(3):121-7.
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    ABSTRACT: We examined amino acid requirements for the growth of the halotolerant Brevibacterium sp. JCM 6894 in the absence and presence of 1.2 M NaCl in a chemically defined medium. The experiment was also carried out in the presence of 1.2 M KCl. As a result, growth was highly enhanced by methionine in the absence and presence of KCl as well as NaCl up to 1.2 M. However, growth in the presence of 150 mM methionine was repressed by leucine (up to 100 mM) and valine (up to 100 mM). Concentration-dependent growth inhibition was observed in the presence of isoleucine (up to 150 mM) and threonine (up to 300 mM). When the cells were incubated in the absence of externally added K(+), growth was strongly repressed, even in the presence of 150 mM methionine. The growth, however, recovered drastically by the addition of 1 mM KCl, regardless of the presence and absence of 1.2 M NaCl. These results indicate that methionine, which seems to be symported into cytoplasm with K(+), plays an important role in the growth of the strain under salt stress.
    Biocontrol science 01/2014; 19(3):151-5.
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    ABSTRACT: Alicyclobacillus acidoterrestris, an obligate aerobe and one of the most harmful bacteria in acidic beverages, requires oxygen for growth. However, the relationship between oxygen availability and its growth has not yet been quantified. We examined the correlation between A. acidoterrestris growth and oxygen availability to determine whether A. acidoterrestris can be controlled by restricting oxygen. Airtight containers were filled with YSG broth and apple juice at various oxygen concentrations. Positive correlation (R(2)=0.9329) was observed between A. acidoterrestris growth and oxygen availability in YSG broth, and a lower but nonetheless slight correlation (R(2)=0.5604) was observed for apple juice. These results indicate that decreased oxygen availability in a container could restrict growth. As results, the addition of reducing compounds along with airtight conditions may help prevent the deterioration of beverages caused by the proliferation of A. acidoterrestris.
    Biocontrol science 01/2014; 19(2):85-8.
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    ABSTRACT: Prediction of microbial growth in mixed culture was studied with a competition model that we had developed recently. The model, which is composed of the new logistic model and the Lotka-Volterra model, is shown to successfully describe the microbial growth of two species in mixed culture using Staphylococcus aureus, Escherichia coli, and Salmonella. With the parameter values of the model obtained from the experimental data on monoculture and mixed culture with two species, it then succeeded in predicting the simultaneous growth of the three species in mixed culture inoculated with various cell concentrations. To our knowledge, it is the first time for a prediction model for multiple (three) microbial species to be reported. The model, which is not built on any premise for specific microorganisms, may become a basic competition model for microorganisms in food and food materials.
    Biocontrol science 01/2014; 19(2):89-92.
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    ABSTRACT: A novel competition model for describing bacterial growth in mixed culture was developed in this study. Several model candidates were made with our logistic growth model that precisely describes the growth of a monoculture of bacteria. These candidates were then evaluated for the usefulness in describing growth of two competing species in mixed culture using Staphylococcus aureus, Escherichia coli, and Salmonella. Bacterial cells of two species grew at initial doses of 10(3), 10(4), and 10(5) CFU/g at 28ºC. Among the candidates, a model where the Lotka-Volterra model, a general competition model in ecology, was incorporated as a new term in our growth model was the best for describing all types of growth of two competitors in mixed culture. Moreover, the values for the competition coefficient in the model were stable at various combinations of the initial populations of the species. The Baranyi model could also successfully describe the above types of growth in mixed culture when it was coupled with the Gimenez and Dalgaard model. However, the values for the competition coefficients in the competition model varied with the conditions. The present study suggested that our model could be a basic model for describing microbial competition.
    Biocontrol science 01/2014; 19(2):61-71.
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    ABSTRACT: Bacillus cereus is a spore-forming bacterium. B. cereus occasionally causes nosocomial infections, in which hand contamination with the spores plays an important role. Therefore, hand hygiene is the most important practice for controlling nosocomial B. cereus infections. This study aimed to determine the appropriate hand hygiene procedure for removing B. cereus spores. Thirty volunteers' hands were experimentally contaminated with B. cereus spores, after which they performed 6 different hand hygiene procedures. We compared the efficacy of the procedures in removing the spores from hands. The alcohol-based hand-rubbing procedures scarcely removed them. The soap washing procedures reduced the number of spores by more than 2 log10. Extending the washing time increased the spore-removing efficacy of the washing procedures. There was no significant difference in efficacy between the use of plain soap and antiseptic soap. Handwashing with soap is appropriate for removing B. cereus spores from hands. Alcohol-based hand-rubbing is not effective.
    Biocontrol science 01/2014; 19(3):129-34.
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    ABSTRACT: Gas plasma generated and applied under two different systems, atmospheric pressure plasma and low pressure plasma, was used to investigate the inactivation efficacy on the seedborne pathogenic fungus, Rhizoctonia solani, which had been artificially introduced to brassicaceous seeds. Treatment with atmospheric plasma for 10 min markedly reduced the R. solani survival rate from 100% to 3% but delayed seed germination. The low pressure plasma treatment reduced the fungal survival rate from 83% to 1.7% after 10 min and the inactivation effect was dependent on the treatment time. The seed germination rate after treatment with the low pressure plasma was not significantly different from that of untreated seeds. The air temperature around the seeds in the low pressure system was lower than that of the atmospheric system. These results suggested that gas plasma treatment under low pressure could be effective in disinfecting the seeds without damaging them.
    Biocontrol science 01/2014; 19(2):99-102.
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    ABSTRACT: Kudoa septempunctata in olive flounder meat was inactivated using 3 distinct freezing methods: liquid freezing for 5 min, air blast freezing at -30℃ for 5 h, and -80℃ for 1 h. The fracture curve of olive flounder meat subjected to liquid freezing resembled that of meat stored at 4℃, indicating that the structure of olive flounder muscle was well preserved. In contrast, air blast freezing induced the disappearance of the fracture point in the fracture curve, indicating that there was deterioration in the meat quality. Liquid freezing preserved the transparency of olive flounder meat to the same degree as that of meat stored at 4°C. However, air blast freezing induced meat cloudiness. These results indicate that liquid freezing can be used for K. septempunctata inactivation without affecting the meat quality.
    Biocontrol science 01/2014; 19(3):135-8.
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    ABSTRACT: Scanning electron microscopy revealed that the rpoS-deficient cells of E. coli K-12 BW25113 (ΔrpoS) increased the number of flagella on the cell surfaces. However, the quantitative analysis of cell colonization showed that the increased number of flagella on ΔrpoS cell surfaces did not cause the enhancement of cell colonization on the surfaces of polyvinyl chloride (PVC), polypropylene (PP) and polystyrene (PS) after 24 h of incubation at 37℃. To facilitate the enhanced expression of curli, the csgA gene was introduced into the ΔrpoS cells. The transformed cells rich in flagella and curli on the cell surfaces were found to make colonies 2-3 times larger than both the wild type and ΔrpoS cells on the PVC, PP and PS surfaces at 37℃. It was thus verified that the reinforcement of csgA gene in the ΔrpoS cells induced the enhanced colonization on the solid surfaces with the increased flagellum and curli expressions.
    Biocontrol science 01/2014; 19(3):147-50.
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    ABSTRACT: The present study evaluates the feasibility of using Artemia franciscana in reducing the Ni concentration of synthetic wastewater by the process of bioaccumulation. Metallothionein protein plays a key role in the uptake of nickel by Artemia. Artemia (Brine shrimp) was exposed to an initial nickel concentration of 40 mg/L. Gradual decrease of nickel was observed from 40 mg/L to 5 mg/L with a removal efficiency of 87.5%. The number of organisms were varied to determine the number for the maximum removal efficiency. Metallothionein protein in Artemia was estimated by the silver saturation method. The physical parameters such as pH were maintained in an alkaline condition of 9-10, temperature was maintained at room temperature and salinity at 30-35‰. These were found to be the optimal conditions for the survival and reduction of nickel by Artemia.
    Biocontrol science 01/2014; 19(2):79-84.
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    ABSTRACT: We offer the first description of the development of a multiple detection technique for fungi by DNA microarray with the simultaneous use of internal transcribed spacer region (ITS) of ribosomal RNA gene and β-tubulin gene probes. The assay uses 12 oligonucleotide probes and multiplex amplification to detect fungal species belonging to various sections of Aspergillus, the Eurotium genus, and the Penicillium genus. The specificity of each probe was tested using 231 reference fungal strains, including 79 target and 152 non-target strains in 102 species of 24 genera. We determined the optimum concentration of the primer pairs for multiplex PCR to be 0.5 μM for the β-tubulin gene and 0.125 μM for the ITS region. In the field trial using 76 specimens containing 323 fungi (up to five fungal strains were included in one specimen), the concordance rate between the DNA microarray and the DNA sequencing results was 97.4% at the species or genus levels.
    Biocontrol science 01/2014; 19(3):139-45.
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    ABSTRACT: Effects of surface contamination and cleaning with hypochlorite wipes on the antibacterial activity of copper-alloyed stainless steel were studied. The antibacterial activity of copper alloyed stainless steel decreased with the increase in the amount of surface contaminant, and the bacterial counts from specimens contaminated with a contaminant, e.g. 1.6 × 10(-2) μg/mm(2) of bovine serum albumin, were not significantly different from those from ordinary stainless steel specimens. The once contaminated surface could regain its antibacterial activity when it was sufficiently wiped clean with sterile wipes loaded with sodium hypochlorite solution.
    Biocontrol science 01/2014; 19(2):73-8.
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    ABSTRACT: A total of 2690 actinomycete strains were screened as potential biological control agents in controlling rice bacterial blight (BB) in Vietnam. From these microorganisms, seventeen actinomycete strains were found to be capable of inhibiting all 10 major Xoo races isolated from Xoo-infected rice leaves. One strain, namely VN08-A-12, contained effective characteristics in selectively inhibiting all 10 races in vitro, but did not inhibit most of the other tested microorganisms. Therefore, VN08-A-12 was subsequently selected for rice field trials for two seasons on two rice cultivars SS1 and KD18. Results showed VN08-A-12 was not only able to reduce Xoo lesion lengths in the two rice cultivars (lesion length reduction of up to 38.3 %), but it also significantly reduced Xoo-related yield loss in infected rice cultivars from the field (yield loss reduction of up to 43.2 %). Interestingly, the culture of this strain also increased the rice yield in healthy rice cultivars (from 2.66 % to 16.98 % for SS1 and from 3.11 % to 5.94 % for KD18 cultivar). The strain VN08-A-12 was shown to be identical to Streptomyces toxytricini. To our knowledge, this is the first study reporting S. toxytricini as a beneficial biological agent for the control of BB in rice.
    Biocontrol science 12/2013; 19(3):103-111.
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    ABSTRACT: A commercial aflatoxin detection ELISA kit, "RIDASCREEN FAST Aflatoxin", was validated with corn samples naturally contaminated with aflatoxin and non-contaminated reference corn samples according to the Japanese Notification Method ShokuAnHatsu 0816-7. The trueness, intra-laboratory repeatability, intermediate precision, limit of detection and limit of quantitaion were found to be 91%, 10%, 6.4%, 0.6 ug/kg and 2 ug/kg, respectively, and the performance of the kit was recognized as complying with all criteria in the Supplement Table of the Notification. These data suggest that this kit is useful as a simplified device to screen out negative corn samples contaminated with less than 4 ug/kg.
    Biocontrol science 08/2013; 19(1):39-43.
  • Biocontrol science 01/2013;
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    ABSTRACT: In May 2011, strain HYNE-20 (=JCM 17837) was isolated from a sample of hot spring water from a foot spa in Niigata, Japan, by a plating method using glycine vancomycin polymyxin B cycloheximide α-ketoglutarate (GVPCα) medium at 36°C for 7 d. The 16S rDNA sequences (1,469bp) of this strain (accession number: AB638719) had high (99.7%) similarity to Legionella rubrilucens, and we identified that this strain was indeed Legionella rubrilucens. When this strain was cultured on buffered charcoal yeast extract α-ketoglutarate (BCYEα) agar at 36°C for 7 d, it exhibited red autofluorescence under UV light (365 nm) . The dominant cellular fatty acids of the strain HYNE-20 were 16:1ω7c (29.9%) , and the guanine-plus-cytosine (G+C) content of DNA was 49.0 mol%. This is the first report that Legionella rubrilucens was isolated from a hot spring for foot soaking.
    Biocontrol science 06/2012; 17(2):101-5.