• Journal of Environmental Health Sciences
• /
• v.19 no.1
• /
• pp.30-36
• /
• 1993

A survey was conducted to measure concentration of airborne microbe in a hospital using RSC air sampler during October~November 1991.The result was as follows: 1) In an agar strip GK-A media for total counts of microbial particles. The highest count were 1384 CFU/m$^3$ in the main lobby, followed by 912 CFU/m$^3$, in the obstetric room, 688 CFU/m$^3$ in 1CU. By gram staining, the distribution for organisms in the air were shown 74.1% in gram possitive cocci followed by 16.8%, in gram possitive bacilli 6.7% in gram negative bacilli and 4.7% in yeast, but low organism was detected in recovery room with 194 CFU/m$^3$. 2) In agar strip S media for Staphylococci the count at the main lobby was detected in the recovery room with 92 CFU/m$^3$, Tests of coagulase were negative Staphylococci with 78%, and positive Staphylococci with 22%. The Staphylococci were highly resistance to penicillin, ampicillin and sensitive to amikacin, cefazolin, gentamycin and chloramphenicol. 3) In agar strip C media for coliform bacteria the colony counts at the main lobby was 139 CFU/m$^3$ and treatment room was 190 CFU/m$^3$, most frequently isolated microorganisms were non fermentative bacilli. 4) In agar strip HS media for yeast and molds. Most frequently colony counts 17~76 CFU/m$^3$, 0.5% lactophenol cotton blue stains were shown unidentified 77.2%, 8.1%, in Penicillium 8.1% in Aspergillus, and 3.8% in mucor.

• Journal of environmental and Sanitary engineering
• /
• v.23 no.2
• /
• pp.1-18
• /
• 2008

The tetrachloroethylene (PCE) dehalogenase of Clostridium bifermentans DPH-1 (a halorespiring organism) was purified, cloned, and sequenced. This enzyme is a homodimer with a molecular mass of ca. 70 kDa and exhibits dehalogenation of dichloroethylene isomers along with PCE and trichloroethylene (TCE). Broad range of substrate specificity for chlorinated aliphatic compounds (PCE, TCE, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,1-dichloroethylene, 1,2-dichloropropene, and 1,1,2-trichloroethane) for this enzyme was also observed. A mixture of propyl iodide and titanium citrate caused a light-reversible inhibition of enzymatic activity suggesting the involvement of a corrinoid cofactor. A partial sequence (81 bp) of the encoding gene for PCE dehalogenase was amplified and sequenced with degenerateprimers designed from the N-terminal sequence (27 amino acid residues). Southern analysis of C. bifermentans genomic DNA using the polymerase chain reaction product as a probe revealed restriction fragment bands. A 5.0 kb ClaI fragment, harboring the relevant gene (designated pceC) was cloned (pDEHAL5) and the complete nucleotide sequence of pceC was determined. The gene showed homology mainly with microbial membrane proteins and no homology with any known dehalogenase, suggesting a distinct PCE dehalogenase. So, C. bifermentans could play some important role in the initial breakdown of PCE and other chlorinated aliphatic compounds in sites contaminated with mixtures of halogenated substances.

• Food Science and Biotechnology
• /
• v.17 no.6
• /
• pp.1337-1340
• /
• 2008

The objective of this study was to evaluate the microbial safety of raw beef used to produce Korean beef jerky, The raw beef samples harbored large populations of microorganisms. In particular, psychrophilic bacteria were found to be most numerous ($9.2{\times}10^3-1.0{\times}10^5\;CFU/g$) in the samples. Mesophilic bacteria and anaerobic bacteria were present in average numbers ($10^3-10^5\;CFU/g$). Spore-forming bacteria and coliforms were not detected below detection limit. Yeast and molds were detected at $2.2{\times}10^1-7.8{\times}10^2\;CFU/g$ in the raw beef. Ten samples of raw beef were analyzed for the presence of pathogenic bacteria. Bacillus cereus was isolated from sample B, G, and H. The B. cereus isolates from raw beef samples were identified with 99.8% agreement according to the API CHB 50 kit.

• The Plant Pathology Journal
• /
• v.34 no.6
• /
• pp.459-469
• /
• 2018

Plants and microorganisms (microbes) use information from chemicals such as volatile compounds to understand their environments. Proficiency in sensing and responding to these infochemicals increases an organism's ecological competence and ability to survive in competitive environments, particularly with regard to plant-pathogen interactions. Plants and microbes acquired the ability to sense and respond to biogenic volatiles during their evolutionary history. However, these signals can only be interpreted by humans through the use of state-of the-art technologies. Newly-developed tools allow microbe-induced plant volatiles to be detected in a rapid, precise, and non-invasive manner to diagnose plant diseases. Beside disease diagnosis, volatile compounds may also be valuable in improving crop productivity in sustainable agriculture. Bacterial volatile compounds (BVCs) have potential for use as a novel plant growth stimulant or as improver of fertilizer efficiency. BVCs can also elicit plant innate immunity against insect pests and microbial pathogens. Research is needed to expand our knowledge of BVCs and to produce BVC-based formulations that can be used practically in the field. Formulation possibilities include encapsulation and sol-gel matrices, which can be used in attract and kill formulations, chemigation, and seed priming. Exploitation of biogenic volatiles will facilitate the development of smart integrated plant management systems for disease control and productivity improvement.

• Korean Chemical Engineering Research
• /
• v.52 no.5
• /
• pp.581-586
• /
• 2014

Main objects for wastewater treatment operation are to maintain effluent water quality and minimize operation cost. However, the optimal operation is difficult because of the change of influent flow rate and concentrations, the nonlinear dynamics of microbiology growth rate and other environmental factors. Therefore, many wastewater treatment plants are operated for much more redundant oxygen or chemical dosing than the necessary. In this study, the optimal control scheme for dissolved oxygen (DO) is suggested to prevent over-aeration and the reduction of the electric cost in plant operation while maintaining the dissolved oxygen (DO) concentration for the metabolism of microorganisms in oxic reactor. The oxygen uptake rate (OUR) is real-time measured for the identification of influent characterization and the identification of microorganisms' oxygen requirement in oxic reactor. Optimal DO set-point needed for the micro-organism is suggested based on real-time measurement of oxygen uptake of micro-organism and the control of air blower. Therefore, both stable effluent quality and minimization of electric cost are satisfied with a suggested optimal set-point decision system by providing the necessary oxygen supply requirement to the micro-organisms coping with the variations of influent loading.

• Applied Biological Chemistry
• /
• v.24 no.2
• /
• pp.85-93
• /
• 1981

For the utilization of natural cellulosic materials by microorganisms, a potent cellulase-producing microorganism was isolated and identified as Trichoderma spp. Rice straw used as a substrate in this study was preliminarily treated with chemical solvents and/or additionally treated with acids and by heat, and then examined with the cellulase produced by the organism. Better results in sugar production by decomposing the straw cellulose were obtained, when the cellulase was produced by cultivating the organism in the selection medium, pH 5.0, for 5 days, and when the pretreated straw substrate was additionally treated with 0.1% $H_2SO_4$ sulfuric acid at $120^{\circ}C$ for 1 hour. The enzyme production was increased by about 20%, when 0.5% urea 0.5% phosphate, 0.1% meat extract, or 5% orange peel was added into the culture medium. For the practical purposes, the sugar production from the rice straw by the cellulase-producing microorganism can be improved by extending the reaction time of the enzyme up to 24 hr or longer.

• Journal of Periodontal and Implant Science
• /
• v.31 no.4
• /
• pp.661-668
• /
• 2001

Anti-P. gingivalis immune sera were obtained from mice immunized with either P. gingivalis alone, or F. nucleaturm followed by P. gingivalis. Two groups of immune sera were examined for binding capacity to P. gingivalis biofilm by confocal laser scanning microscope, Antibody avidity index was also determined for each immune sera. The results indicated that prior immunization of mice with F. nucleaturm impaired P. gingivalis-specific immune sera in binding capacity to biofilm and antibody avidity to P. gingivalis. Elevated antibody responses in patients with destructive periodontal disease has often been related to suboptimal level of protective antibody $(opsonophagocytosis)^{1-3)}$ while post-immune sera obtained with experimental animals using a single periodontal pathogen demonstrated satisfactory levels of protective function against the homologous bacterial $challenge^{4,5)}$.The reason is unclear why elevated IgG responses in periodontal patients to periodontal pathogens do not necessarily reflect their protective function. Such an immune deviation might be derived from the fact that destructive periodontal disease is cumulative result of immunopathologic processes responding to an array of different colonizing microorganisms sequentially infecting in the subgingival environmental niche. Fusobacterium nucleaturm is one of the key pathogens in gingivitis, in the transitional phase of conversion of gingivitis into destructive periodontitk, and in adult $periodontitis^{6-8)}$. It also plays a central role in coaggregation with other important microbial species in subgingival $area^{6,9,10)}$ as well as in $biofilm^{11)}$, especially with Porphyromonas gingjvalis in synergism of virulence in human periodontal disease or in animal $models^{12-14)}$. This organism has also been reported to have immune modulating activity for secondary immune response to Actinobacillus $actinomycetemcomitans^{15)}$. It is presumed that sequential colonization and intermicrobial coaggregation between intermediate and late colonizers could potentially modulate the immune responses and development of specific T cell phenotypes in periodontal lesions. We have recently demonstrated the skewed polarization of P. gingivalis-specific helper T cell clones in mice immunized with F. nucleaturm followed by P. $gingivalis.^{16)}$. Consequently F. nucleaturm may initially prime the immune cells and modify their responses to the successive organism, P. gingivalis. This could explain why one frequently observes non-protective serum antibodies to P. gingivalis in periodontal patients in contrast with those obtained from animals that were immunized with $P.gingivalis\;alone^{17)}$. The present study was performed to investigate the immune modulating effect of F. nucleatum on serum binding to experimental biofilms and the avidity of anti-P. gingivalis antibody.

• Applied Biological Chemistry
• /
• v.26 no.1
• /
• pp.35-40
• /
• 1983

The inhibitory activity of 20 Lactic strains from Kimchi was tested against Escherichia coli and other microorganisms. Of the lactic strains investigated, A7 (Pediococcus cerevisiae) and C4(Leuconostoc spp.) were the most effective in restricting the growth of test organisms. The mixed culture inoculation of each selected lactic strain and Escherichia coli resulted in a drastic reduction in the plate count of Escherichia coli after 24 hours. Similar results were obtained when Staphylococcus aureus and Bacillus cereus were used as test organisms. For all test organisms, the presence of A7 caused a higher death rate constant than that of C4. Addition of catalase in the mixed culture did not prevent inhibition, suggesting that hydrogen peroxide did not cause the inhibition. The filtrate of A7 culture added to Escherichia coli showed identical inhibitory action, however heat treatment of filtrate at $80^{\circ}C$ 30min. destroyed the inhibitory activity. A7 filtrate treated with trypsin substantially lost the inhibitory effect, but not by pepsin. The results imply that the protein-like compound(s) is the principal inhibitor produced by this lactic strain.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.8
• /
• pp.1202-1208
• /
• 2009

Synbiotics is the term used for a mixture of probiotics (live microbial feed additives that beneficially affects the host animal) and prebiotics (non-digestible food ingredients that beneficially affect the organism). This study investigated the effect of probiotics from anaerobic microflora with prebiotics on growth performance, nutrient digestibility, noxious gas emission and fecal microbial population in weaning pigs. 150 pigs with an initial BW of 6.80${\pm}$0.32 kg (20 d of age) were randomly assigned to 5 dietary treatments as follows: i) US, basal diet+0.15% antibiotics (0.05% oxytetracycline 200 and 0.10% tiamulin 38 g), ii) BS, basal diet+0.2% synbiotics (probiotics from bacteria), iii) YS, basal diet+0.2% synbiotics (probiotics from yeast), iv) MS, basal diet+0.2% synbiotics (probiotics from mold), v) CS, basal diet+0.2% synbiotics (from compounds of bacteria, yeast and mold). The probiotics were contained in $10^{9}$ cfu/ml, $10^{5}$ cfu/ml and $10^{3}$ tfu/ml of bacteria, yeast and molds, respectively. The same prebiotics (mannan oligosaccharide, lactose, sodium acetate and ammonium citrate) was used for all the synbiotics. Pigs were housed individually for a 16-day experimental period. Growth performance showed no significant difference between antibiotic treatments and synbiotics-added treatments. The BS treatment showed higher (p<0.05) dry matter (DM) and nitrogen digestibility while ether extract and crude fiber digestibility were not affected by the dietary treatment. Also, the BS treatment decreased (p<0.05) fecal ammonia and amine gas emissions. Hydrogen sulfide concentration was also decreased (p<0.05) in BS, YS and MS treatments compared to other treatments. Moreover, all the synbioticsadded treatments increased fecal acetic acid concentration while the CS treatment had lower propionic acid concentration than the US treatment (p<0.05) gas emissions but decreased in fecal propionate gas emissions. Total fecal bacteria and Escherichia coli populations did not differ significantly among the treatments, while the Shigella counts were decreased (p<0.05) in synbiotics-included treatment. Fecal bacteria population was higher in the YS treatment than other treatments (p<0.05). The BS treatment had higher yeast concentration than YS, MS and CS treatments, while US treatment had higher mold concentrations than MS treatment (p<0.05). Therefore, the results of the present study suggest that synbiotics are as effective as antibiotics on growth performance, nutrient digestibility and fecal microflora composition in weaning pigs. Additionally, synbiotics from anaerobic microflora can decrease fecal noxious gas emission and synbiotics can substitute for antibiotics in weaning pigs.

• Journal of Life Science
• /
• v.25 no.6
• /
• pp.715-723
• /
• 2015

Insects represent the largest class within the animal kingdom in terms of species number. Humans had been utilized insect in the broad area, including food, agriculture, industry, pharmaceuticals and so on. At present, insects are emerging as a leading group for identifying and extracting novel bioactive substances due to enormous number and a high nutritional value. Insects rely on a suite of systemic response to resist infection such as immune cells, hemocytes, activation of enzymes cascades, and antimicrobial peptide/protein. Among the substances, antimicrobial peptides (AMPs) are main components of potent antimircrobial innate defense system into the insect hemolymph. AMPs raise influential candidate as avenue to resolve the development of antibiotic-resistant microbial organism. Insect AMPs are classified into four main classes: cecropins, insect defensins, glycine/proline-rich peptides. Insect AMPs have been purified, over 150. In this review, AMPs derived from several insects were summarized including honey bee, dung beetle, butterfly and longicorn beetle. These peptides almost exhibited potent antimicrobial activities against human microbial pathogens without causing remarkable hemolysis to erythrocytes excluding melittin, and their mode of action(s) are based on disruption of the plasma membrane or fungal apoptosis. Therefore, study of insect AMPs is expected to be useful for designing novel therapeutic antimicrobial applications.