• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.7
• /
• pp.988-995
• /
• 2019

Objective: This study was conducted to estimate the temperature and microbial changes of corn silages during aerobic exposure. Methods: Kwangpyeongok (KW) and Pioneer 1543 (PI) corn hybrids were harvested at 29.7% of dry matter and chopped to 3 to 5 cm lengths. Homo (Lactobacillus plantarum; LP) or hetero (Lactobacillus buchneri; LB) fermentative inoculants at $1.2{\times}10^5$ colony forming unit/g of fresh forage was applied to the chopped corn forage which was then ensiled in quadruplicate with a $2{\times}2$ (hybrid${\times}$inoculant) treatment arrangement for 100 days. After the silo was opened, silage was sub-sampled for analysis of chemical compositions, in vitro digestibility, and fermentation indices. The fresh silage was continued to determine aerobic exposure qualities by recorded temperature and microbial changes. Results: The KW silages had higher (p<0.01) in vitro digestibilities of dry matter and neutral detergent fiber than those of PI silages. Silages applied with LB had higher (p<0.001) acetate concentration, but lower (p<0.01) lactate concentration and lactate to acetate ratio than those of LP silages. The interaction effect among hybrid and inoculant was detected in acetate production (p = 0.008), aerobic stability (p = 0.006), and lactic acid bacteria count (p = 0.048). The yeast was lower (p = 0.018) in LB silages than that in LP silages. During the aerobic exposure, PI silages showed higher (p<0.05) temperature and mold than KW silages, while LP silages had higher (p<0.05) lactic acid bacteria and yeast than LB silages. Conclusion: The results indicated that the changes of silage temperature during aerobic exposure seems mainly affected by mold growth, while applied LB only enhanced aerobic stability of PI silages.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.50 no.1
• /
• pp.65-74
• /
• 2023

This study compared the surface roughness and microbial adhesion characteristics of Omnichroma, a novel composite resin developed using "smart chromatic technology", with those of two other conventional composite resins with different filler compositions. A total of 144 specimens were fabricated using 3 types of composite resins: Omnichroma (nano-spherical), Filtek Z350XT (nanofill), and Tetric N-Ceram (nanohybrid) and, divided into 3 groups of 48. Finishing was performed using tungsten carbide burs. Specimens were then divided into 3 subgroups using different polishing methods: Control, SofLex, and PoGo. Surface roughness was analyzed quantitatively and qualitatively using an atomic force microscope and a scanning electron microscope. Microbial adhesion was assessed by culturing Streptococcus mutans on the specimens for 24 hours and then measuring colony-forming units attached to the upper surface. The surface roughness (Ra) of Omnichroma was 0.123 ㎛ after finishing, and it exhibited a smooth surface compared to the other resins. However, after polishing, there were no significant differences in the surface roughness between the three composite groups, regardless of the polishing methods. The surfaces of the Control subgroups were significantly rougher than those of the SofLex subgroups in all 3 composite groups. However, except for Tetric N-Ceram, there were no significant differences between the Control and PoGo subgroups in the other composite groups. Microbial adhesion assessment showed no significant differences between any of the 3 composite resin subgroups; however, Omnichroma exhibited higher microbial adhesion than the other two composites. No significant correlation was observed between surface roughness and microbial adhesion.

• Korean journal of applied entomology
• /
• v.52 no.4
• /
• pp.357-364
• /
• 2013

Bee-vectoring is a new crop protection technology used for suppressing insect pests and diseases in crops by disseminating microbial agents into plants during bee pollination activities. In this study, we conducted bee-vectoring trials in cherry tomato greenhouses by using the bumble bee (Bombus terrestris), a microbial agent (Bacillus subtilis) and a new dispenser, and we measured the delivered quantity of microbial agent. Bacterial colony forming units (CFUs) in bees exiting a dispenser ranged from $9.0{\times}10^5$ to $1.9{\times}10^6$ per bee. At greenhouse trials in the National Academy of Agricultural Science (NAAS) trials, 3,300 - 8,500 CFUs per flower were counted and 80 - 100% of the flower samples contained detectable concentrations. There was no significant difference in CFU density between microbial replacement intervals (once a week vs twice a week) in the NAAS trials. In a commercial greenhouse trial, 1,800 - 2,400 CFUs per flower were found, and 83 - 93% of the flower samples contained detectable concentrations. CFUs detected in bee-vectored flowers increased by approximately 75 times before bee-vectoring. The mortality of bumble bees in the NAAS trials was, on average, 22% and little negative effects were observed on the bumble bee colonies. The yield difference for cherry tomatoes in the NAAS trials was not significant between treatments. When we select additional microbial agents that can be disseminated using this technology and create a detailed plan based on insect pests and disease incidence, we can apply this technology in greenhouses for growing tomatoes and strawberries in the near future.

• Korean Journal of Soil Science and Fertilizer
• /
• v.32 no.1
• /
• pp.76-83
• /
• 1999

Studies were conducted during 2 months from May of 1997 to evaluate the effects of pig manure compost(PMC) on soil microbial flora. To do so, a field experiment of Chinese cabbage(Brassica campestris L.) was conducted in a randomized block design on a sandy loam soil and microbial floral characteristics in soils were analyzed. Treatments to control included the application of PMC at (A) $8Mg\;ha^{-1}$CM-8), (B) $29Mg\;ha^{-1}$(CM-2,9), and (C) $57Mg\;ha^{-1}$(CM-57), and of chemical fertilizer(D) at $320N-80P_2O_5-200K_2O\;kg\;ha^{-1}$(NPK). In each treatment, the rhizosphere and non-rhizosphere soils were tested for the analysis of microbial populations. The populations of bacteria, actinomycetes, and fungi increased in soils with the applications of PMC and chemical fertilizer, but that of Bacillus sp. decreased. However, the population of fluorescent Pseudomonas sp. was reduced in NPK plots only. With increasing application rates of PMC, the number of colony forming units(cfu) of bacteria (Pseudomonas sp. and actinomycetes) and fungi increased. in all PMC-treated plots, the population density peaked at early growth stage for bacteria(including Bacillus sp.), at late growth for fluorscent Pseudomonas sp., and at harvest for fungi and actinomycetes. The rhizosphere effect was greatest for fluorscent Pseudomonas sp. As the application rates of PMC increased, Total N, organic matter, available phosphate, and exchangeable -K, -Ca, and -Mg increased compared to control, but soil pH was lowered. In NPK plots, EC was 3.4-fold and exchangeable K was 5-fold higher than control.

• Horticultural Science & Technology
• /
• v.30 no.4
• /
• pp.442-448
• /
• 2012

Many outbreaks of food-borne illnesses have been associated with the consumption of fresh vegetables and fruits contaminated with food-borne pathogens. Contaminated medium, manure and irrigation water are probable vehicles for the pathogen in many outbreaks. The aim of this study was to determine the potential transfer of Escherichia coli and Bacillus cereus from medium and soil fertilized with contaminated compost or irrigation with contaminated water to the edible parts of lettuce. Moreover, survivals of the two pathogens on lettuce contaminated medium, soil and irrigation water were estimated. Lettuce seeds were planted in medium contaminated with 7.5 log colony forming unit (CFU)/g of E. coli and B. cereus. Seedlings grown in the contaminated medium were transplanted in soil fertilized with contaminated pig manure compost or uncontaminated soil. Contaminated irrigation water with E. coli and B. cereus at 8.0 log CFU/mL was applied only once on the plant by sprinkle irrigation and surface irrigation. Although E. coli and B. cereus in medium and sprouted lettuce after planting seeds were reduced as time passed, these pathogens survived in seedling raising stage for extended periods. The numbers of E. coli and B. cereus in lettuce grown on contaminated soil were detected over 4.0 log CFU/g for 21 days. The numbers of E. coli and B. cereus in lettuce applied by sprinkle irrigation were higher than those of surface irrigation by 5.0 log CFU/g. Our results indicated that contaminated medium, soil and irrigation water can play an important role in the presence of food-borne pathogens on vegetables.

• Journal of Life Science
• /
• v.28 no.3
• /
• pp.361-368
• /
• 2018

This study investigated the diversity of communities of intestinal microorganisms, separated from the intestinal organs of Red tilefish (Branchiostegus japonicas), collected on the Jeju Coast. First, in the isolation of 1.5% BHIA, MA, TSA and R2A Agar on the medium, there were most colonies in 1.5% BHIA. The results of aerobic culture and anaerobic culture were $1.7{\times}10^6CFU/g^{-1}$ and $1.1{\times}10^5cfu/g^{-1}$, respectively, on average, and 147 pure colonies were separated in total. In 16S rDNA sequencing, there were 58 genera and 74 species, showing 95-100% similarity with the basic strain. They were divided broadly into 5 phyla, and as the main phyletic group, Proteobacteria phylum comprised 50% with 9 families, 35 genera and 35 species of Moraxellaceae, Rhodobacteraceae, Shewanellae, Halomondaceae, Enterobacteriaceae, Vibrionaceae, Hahellaceae, Pseudomonadaceae, and Erythrobacteraceae, with the highest index of dominance. Actinobacteria phylum comprised 24% with 8 families, 11 genera and 17 species of Microbacteriaceae, Intrasporangiaceae, Dietziaceae, Dermabacteraceae, Dermacoccaceae, Nocardiodaceae, Brevibacteriaceae and Propionobacteriacea; Firmicutes phylum, 16% with 6 families, 8 genera and 17 species of Bacillaceae, Staphylcoccaceae, Planococcaceae, Streptococcaceae, Paenibacillaceae and Clostridiaceae; Bacteroidetes phylum, 6% with 2 families, 3 genera and 4 species of Cyclobacteriaceae and Flavobacteriaceae; and Deinococcus-Thermus phylum, 4% with 1 family, 1 genus and 1 species of Deinococcaceae.

• Journal of Animal Science and Technology
• /
• v.51 no.4
• /
• pp.321-328
• /
• 2009

A total of fourteen, 1-wk-old male Holstein calves were allotted into two groups consisted of control (CON) and IGY which was orally administrated with immunoglobulin yolk (IgY) for 1wk. Calves in both groups were provided with milk replacer according to feeding program and had ad libitum access to timothy hay for the entire experimental period (7wks). At 0, 7 and 49 day of experiment, blood samples were collected from the jugular vein of calves to investigate blood biochemical profiles and the differential count (%) of white blood cell (WBC). We also monitored growth performance and colony forming unit (CFU) of fecal microbial population in calves. The adminstration of IgY in calves did not affect body weight and weight gain during 49 days feeding trial compared with control group. The CFU of E. coli and Lactobacilli in the feces of calves were not significantly affected by IgY treatment, whereas the score of the calf scours during day 43 to 49 in IgY group showed a significant (P<0.05) solid type. There were no differences in plasma biochemical components including total protein, albumin, immunoglobulin and the other indicators. As for WBC differential count (%), there was no statistical difference in the percentages of neutrophil, lymphocyte, monocyte, eosinophil and basophil at 0, 7 and 49 days after the oral supplementation of IgY. In conclusion, the oral supplementation of IgY as an immunostimulant did not affect growth performance, fecal microbial population, blood biochemical profile and WBC differential count in Holstein calves.

• Korean Journal of Microbiology
• /
• v.46 no.3
• /
• pp.262-269
• /
• 2010

To investigate a quantitative evaluation of the actinobacteria, we have collected samples from various kinds of bamboo forest soil. Each different layers contained $2.7{\times}10^6-2.7{\times}10^8$ CFU/g of actinobacteria which was the highest in litter layers of Sasa boreali forest soil. We obtained 330 actinobacteria from different layers of bamboo forest soil; litter (100 strains), humus (70 strains), and rhizosphere soil (160 strains). Based on the colony morphology (aerial mycelium, substrate mycelium, and soluble pigment), isolates were divided into thirty-six groups and we selected 50 representative isolates. 16S rRNA gene sequence analysis showed Streptomyces was major actinobacteria (94%) and they were categorized as cluster I (2 strains), II (35 strains), III (6 strains), and IV (7 strains), respectively. The diversity index of 50 Streptomyces collected from the bamboo forest soil was calculated with the Shannon-Wiener method. Bamboo litter showed higher diversity index level of 3.33 than that of humus and rhizosphere soil. Also, antibiotic activities of our isolates were investigated against Botrytis cinerea, Xanthomonas campestris, Xanthomonas axonopodis pv. vesicatoria, and Bacillus cereus and found in 74, 16, 25, and 24 strains, respectively.

• Korean journal of applied entomology
• /
• v.40 no.3
• /
• pp.259-264
• /
• 2001

Toxicological studies of two potential biological control agents, the entomopathogenic nematode (Steinernema carpocapsae) and the symbiotic bacteria (Xenorhabdus nematophilus) were conducted against two beneficial insects and one mammal species. Two microbial agents varied in their toxicities between two insect species: an ant, Pristomyrmex pungens, and silkworm, Bombyx mori. In oral toxicity test, the symbiotic bacteria resulted in significant lethal [half lethal concentration of $1.4$\times$10^3$colony-forming units (cfu)/ml] on the ants, while they gave little lethal effect (half lethal concentration of more than $10^{8}$ cfu/ml) on the silkworms. The nematodes, however, gave significant lethal effect [half lethal concentration of 4 infected juveniles (IJs)/ml] on the silkworms, while they did little lethal effect (half lethal concentration of 150,000 IJs/ml) on the ants in topical assays. Both the nematodes and the bacteria did not give lethal effect to the albino rats, Rattus norvegicus, when they were fed orally into the rats. Also, any of these microbial agents were not detected in the internal organs of the treated rats.

• Korean journal of applied entomology
• /
• v.49 no.4
• /
• pp.409-416
• /
• 2010

An entomopathogenic bacterium, Photorhabdus temperata ssp. temperata (Ptt), suppresses insect immune responses and facilitates its symbiotic nematode development in target insects. The immunosuppressive activity of Ptt enhances pathogenicity of various microbial pesticides including Bacillus thuringiensis (Bt). This study was performed to select a cheap and efficient bacterial culture medium for large scale culturing of the bacteria. Relatively cheap industrial bacterial culture media (MY and M2) were compared to two research media, Luria-Bertani (LB) and tryptic soy broth (TSB). In all tested media, a constant initial population of Ptt multiplied and reached a stationary phase at 48 h. However, more bacterial colony densities were detected in LB and TSB at the stationary phase compared to two industrial media. All bacterial culture broth gave significant synergism to Bt pathogenicity against third instars of the diamondback moth, Plutella xylostella. Production of bacterial metabolites extracted by either hexane or ethyl acetate did not show any significant difference in total mass among four culture media. Reverse phase HPLC separated the four bacterial metabolites, which were not much different in quantities among four bacterial culture broths. This study suggests that two industrial bacterial culture media can be used to economically culture Ptt in a large scale.