• Food Science of Animal Resources
• /
• v.36 no.2
• /
• pp.186-193
• /
• 2016

This study aimed to inhibit Escherichia coli (E. coli) O157:H7 artificially contaminated in fresh meat using bacteriophage. Among 14 bacteriophages, the highly lytic bacteriophage BPECO19 strain was selected to inhibit E. coli O157:H7 in artificially contaminated meat samples. Bacteriophage BPECO19 significantly reduced E. coli O157:H7 bacterial load in vitro in a multiplicity of infection (MOI)-dependent manner. E. coli O157:H7 was completely inhibited only in 10 min in vitro by the treatment of 10,000 MOI BPECO19. The treatment of BPECO19 at 100,000 MOI completely reduced 5 Log CFU/cm² E. coli O157:H7 bacterial load in beef and pork at 4 and 8h, respectively. In chicken meat, a 4.65 log reduction of E. coli O157:H7 was observed at 4 h by 100,000 MOI. The treatment of single bacteriophage BPECO19 was an effective method to control E. coli O157:H7 in meat samples.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.2
• /
• pp.184-188
• /
• 2013

In the continued search for inhibitors of enoyl-acyl carrier protein (ACP) reductase, we found that four acylbenzenediol sulfate metabolites from Streptomyces sp. AN1761 potently inhibited bacterial enoyl-ACP reductases of Staphylococcus aureus, Streptococcus pneumoniae, and Mycobacterium tuberculosis. Their structures were identified as panosialins A, B, wA, and wB by MS and NMR data. They showed stronger inhibition against S. aureus FabI and S. pneumoniae FabK with $IC_{50}$ of 3-5 ${\mu}M$ than M. tuberculosis InhA with $IC_{50}$ of 9-12 ${\mu}M$. They also exhibited a stronger antibacterial spectrum on S. aureus and S. pneumoniae than M. tuberculosis. In addition, the higher inhibitory activity of panosialin wB than panosialin B on fatty acid biosynthesis was consistent with that on bacterial growth, suggesting that they could exert their antibacterial activity by inhibiting fatty acid synthesis.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.2
• /
• pp.128-132
• /
• 2001

Bacterial vaginosis can be treated by restoring the normal vaginal flora using lactobacilli. Lactobacillus crispatus KLB46 that was isolated from the human vagina has a string antimicrobial activity and was grown in a batch and in a continuous fermentor. During batch cultivation, the maximum specific growth rate of L. crispatus KLB 46 was 0.63h(sup)-1 and the highest viable cell count (1.9$\times$10(sup)9 CFU/mL) was obtained at pH 5.5. L. crispatus KLB 46 did not grow well at either pH 3.5 or 7.5. During continuous cultivation, the highest viable cell count (1.53$\times$10(sup)9 CFU/mL) was obtained at a dilution rate of 0.32h(sup)-1, and was 7.33$\times$10(sup)11 CFU L(sup)-1 h(sup)-1, that is approximately 5 times higher than that obtained from batch culture.

• Korean journal of applied entomology
• /
• v.14 no.3 s.24
• /
• pp.155-161
• /
• 1975

The results of studies on the synthesis of B group vitamins by plant pathogenic bacteria indicate that most bacteria utilize thiamine, nicotinic acid, biotin and P-Aminobenzoic acid as growth factors. Riboflavin (vitamin $B_2$) was produced by most bacterial genera including the Corynebacteria but with the exception of C. rathay and C.fasciant. The results suggest that the ability to produce riboflavin is not a generic characteristic of Corynebacterium, and that the accuracy of the ultra-violet light method (one of the diagnostic tests for potato bacterial ring rot disease caused by Corynebacterium sepedonicum) must he reconsidered.

• Environmental Engineering Research
• /
• v.24 no.1
• /
• pp.17-23
• /
• 2019

This study monitored changes in the level of heterotrophic bacteria in the filtrate and investigated the effect of stagnant water on it, using a batch-operated, gravity-driven membrane system for household water treatment. The filtration test was carried out in the presence and absence of stagnant water in the filtrate line. The results showed that stagnant water accelerated the heterotrophic bacteria levels, measured by heterotrophic plate count, even though the heterotrophic plate count of the filtrate finally increased up to $10^5CFU/mL$ regardless of the presence of stagnant water. When the change in heterotrophic plate count of a batch was monitored over filtration time, heterotrophic plate count of the filtrate rapidly decreased within 5 min for each batch filtration. Biofilm formation on the filtrate line was observed in the presence of stagnant water. The biofilm fully covered the filtrate line and contained numerous microorganisms. During storage after filtration, heterotrophic plate count increased exponentially. To improve the filtrate quality of a filtration-based household water treatment system, therefore, the stagnant water in the filtrate line should be minimized, the filtrate produced at the first 5 min is recommended not to be used as potable water, and the storage of filtrate should be avoided.

• Microbiology and Biotechnology Letters
• /
• v.47 no.2
• /
• pp.269-277
• /
• 2019

In the present study, we have studied the bioremediating capability of bacterial strain against six heavy metals. The strain was isolated from river Yamuna, New Delhi which is a very rich repository of bioremediating flora and fauna. The strain was found to be Gram positive as indicated by Gram staining. The strain was characterized using 16s rRNA gene sequencing and the BlastN result showed its close resemblance with the Cellulosimicrobium sp. As each treatment has its own toxicity eliciting expression of different factors, we observed varied growth characteristics of the bacterial isolate and its protein content in response to different heavy metals. The assessment of its bioremediation capability showed that the strain Cellulosimicrobium sp. has potential to consume or sequester the six heavy metals in this study in the following order iron > lead > zinc > cooper > nickel > cadmium. Thus, the strain Cellulosimicrobium sp. isolated in the present study can be a good model system to understand the molecular mechanism behind its bioremediating capabilities under multiple stress conditions.

• 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.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.9
• /
• pp.1424-1433
• /
• 2019

DDT is a hydrophobic organic pollutant, which can be bio-accumulated in nature and have adverse consequences on the physical condition of humans and animals. This study investigated the relationship between the white-rot fungus Pleurotus eryngii and biosurfactant-producing bacterium Ralstonia pickettii associated with the degradation of DDT. The effects of R. pickettii on fungal development were examined using in vitro confrontation assay on a potato dextrose agar (PDA) medium. R. pickettii culture was added to the P. eryngii culture at 1, 3, 5, 7, and 10 ml ($1ml{\approx}1.44{\times}10^{13}CFU$). After 7 d incubation, about 43% of the initial DDT ($12.5{\mu}M$) was degraded by the P. eryngii culture only. The augmentation of 7 ml of R. pickettii culture revealed a more highly optimized synergism with DDT degradation being approximately 78% and the ratio of optimization 1.06. According to the confrontational assay, R. pickettii promoted the growth of P. eryngii towards the bacterial colony, with no direct contact between the bacterial cells and mycelium (0.71 cm/day). DDD (1,1-dichloro-2,2-bis(4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene), and DDMU (1-chloro-2,2-bis(4-chlorophenyl) ethylene) were identified as metabolic products, indicating that the R. pickettii could enhance the DDT biodegradation by P. eryngii.

• International Journal of Clinical Preventive Dentistry
• /
• v.14 no.4
• /
• pp.216-221
• /
• 2018

Objective: In this study, we tried to investigate the antimicrobial activity of natural herbaceous plant-derived essential oils against oral disease-causing bacterial strains and establish the scientific evidences to apply them to the dentifrice, mouthwash, and other uses. Methods: We used the disk diffusion method with 23 types of 100% natural essential oils to verify the antimicrobial effect against Streptococcus mutans, Porphyromonas gingivalis, and Lactobacillus rhamnosus. After adhering to the surface of the plate culture medium, $20{\mu}l$ of the essential oil was prepared, and the diameter of the transparent ring was measured after incubation for 24 hours. All the experiments were repeated three times. Results: Among 23 types of oils, 13 were effective against all three strains: myrrh, ginger, basil, carrot seed, tea tree, patchouli, ylang ylang, cypress, lemongrass, cinnamon, peppermint, lavender, and eucalryptus. Seventeen oils were effective against S. mutans, and myrrh, basil, and carrot seed showed high antimicrobial activity. Eighteen oils were effective against P. gingivalis, and tea tree, carrot seed, and cinnamons showed high antimicrobial activity. Sixteen oils were effective against L. rhamnosus, and carrot seed and peppermint cinnamon showed high antimicrobial activity. Conclusion: Consequently, 13 essential oils showed the antimicrobial activity against three bacterial strains, which indicates these essential oils might be used as the effective materials to suppress the growth of oral-disease inducing microorganisms. Moreover, essential oils that have been analyzed activities in this study will be mixed up within the constant range and analyzed their antimicrobial effects to examine the synergistic activity among them.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.2
• /
• pp.195-204
• /
• 2022

Chinese chive (Allium tuberosum Rottler) has potential risks associated with pathogenic bacterial contamination as it is usually consumed raw. In this study, we investigated the microbiota of Chinese chives purchased from traditional markets and grocery stores in March (Spring) and June (Summer) 2017. Differences in bacterial diversity were observed, and the microbial composition varied across sampling times and sites. In June, potential pathogenic genera, such as Escherichia, Enterobacter, and Pantoea, accounted for a high proportion of the microbiota in samples purchased from the traditional market. A large number of pathogenic bacteria (Acinetobacter lwoffii, Bacillus cereus, Klebsiella pneumoniae, and Serratia marcescens) were detected in the June samples at a relatively high rate. In addition, the influence of the washing treatment on Chinese chive microbiota was analyzed. After storage at 26℃, the washing treatment accelerated the growth of enterohemorrhagic Escherichia coli (EHEC) because it caused dynamic shifts in Chinese chive indigenous microbiota. These results expand our knowledge of the microbiota in Chinese chives and provide data for the prediction and prevention of food-borne illnesses.