• Journal of Pharmacopuncture
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• v.10 no.3
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• pp.47-52
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• 2007

Objective This experimental study was performed to investigate the effect of Coptidis rhizoma extract compared with quantity on Staphylococcus aureus that induce keratitis. Methods Minimal inhibitory concentration(MIC) was measured by dropping to $50{\mu}l$　according to density Coptidis rhizoma extract(100%, 10%, 1%, 0.1%) compared with quantity(40g, 80g, 160g). Anti-bacterial potency was measured by the size of inhibition zone with change of volume. Results 1. MIC on Staphylococcus aureus in Coptidis rhizoma extract was showed anti-bacterial potency compared with quantity and density in 100% and 10% of all samples(40g, 80g, 160g). 2. MIC on Staphylococcus aureus in Coptidis rhizoma extract(40g, 80g, 160g) was showed anti-bacterial potency compared with quantity all samples($20{\mu}l,\;30{\mu}l,\;40{\mu}l,\;50{\mu}l$) in 100% density. 3. MIC on Staphylococcus aureus in Coptidis rhizoma extract(40g, 80g, 160g) was showed anti-bacterial potency compared with quantity all samples ($20{\mu}l,\;30{\mu}l,\;40{\mu}l,\;50{\mu}l$) in 100% density. Anti-bacterial potency of 80g Coptidis rhizoma extract decreased compared with 40g. Anti-bacterial potency of 160g Coptidis rhizoma extract decreased compared with 40g in $20{\mu}l,\;30{\mu}l$. Conclusions Coptidis rhizoma extract was showed anti-bacterial potency compare with quantity and density. In herbal drug, antibacterial potency compare with quantity and density must be studied.

• Journal of Pharmacopuncture
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• v.10 no.1 s.22
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• pp.79-84
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• 2007

Objective : This experimental study was performed to investigate the effect of Coptidis rhizoma extract compared with quantity on Staphylococcus epidermidis that induce keratitis. Methods : MIC was measured by dropping to 50${\mu}l$ according to density Coptidis rhizoma extract(100%, 10%, 1%, 0.1%) compared with quantity(40g, 80g, 160g). Anti-bacterial potency was measured by the size of inhibition zone with change of volume. Results : 1. MIC on Staphylococcus epidermidis in Coptidis rhizoma extract was showed anti-bacterial potency compared with quantity and density in 100% and 10% of all samples(40g, 80g, 160g). 2. MIC on Staphylococcus epidermidis in Coptidis rhizoma extract(40g, 80g, 160g) was showed anti-bacterial potency compared with quantity all samples($20{\mu}l$, $30{\mu}l$, $40{\mu}l$, $50{\mu}l$) in 100% density, but anti-bacterial potency of 80g, $50{\mu}l$ Coptidis rhizoma extract decreased compared with 40g, $50{\mu}l$. 3. MIC on Staphylococcus epidermidis in 40g Coptidis rhizoma extract was showed in $50{\mu}l$, $40{\mu}l$ of 10% density, 80g Coptidis rhizoma extract was showed in $50{\mu}l$ of 10% density, 160g Coptidis rhizoma extract was showed in $50{\mu}l$, $40{\mu}l$, $30{\mu}l$ of 10% density. Conclusions : Coptidis rhizoma extract was showed anti-bacterial potency compare with quantity and density. In herbal drug, anti-bacterial potency compare with quantity and density must be studied.

• Journal of Plant Biotechnology
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• v.30 no.3
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• pp.215-219
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• 2003

This study was conducted to find optimum bacterial density for improving the efficiency of transformation mediated by Agrobacterium tumefaciens in apples. Regeneration(15％) and transformation frequency(10％) were increased in resuspension-culture density $A_{600}$ 1.3 from preculture density $A_{600}$ 0.7 of Agrobacterium tumefaciens in ′Fuji′. In ′Gala′, 20% regeneration and 16% transformation frequency were observed at optimum bacterial density $A_{600}$ 0.7 form preculture density $A_{600}$ 1.3. ′Mclntosh as well as "Gala" were 25％regeneration and 10％ transformation frequency. Hence a frequency optimum condition of bacterial density for the efficient transformation of apple could be depend on apple genotypes.

• Journal of Forest and Environmental Science
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• v.34 no.1
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• pp.61-65
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• 2018

To know if small changes in rearing water temperature and density affect the number of bacterial and fungal colonies in metamorphosed frogs, Dybowski's frog tadpoles were reared from Gosner 25-26 stages at either low ($1^{\circ}C$ low to ambient water temperature), ambient, or high ($1^{\circ}C$ high) water temperature (each 15 tadpoles in 20 L water) condition and at either low (10 tadpoles/20 L water), medium (20 tadpoles), or high (30 tadpoles) density condition. Immediately after metamorphosis, we sampled bacteria and fungi from skin, liver, and heart of six metamorphosed frogs, randomly selected for each treatment group. After separate incubation of bacteria and fungi on 3M Petrifilm plates, we counted the number of bacterial and fungal colonies appeared on the plates and compared the numbers among the temperature and density treatment groups. For temperature treatment, high-temperature group had fewer bacterial colonies, while low-temperature group had more fungal colonies than the other two groups. For density treatment, low-density group had fewer bacterial colonies than the other two groups, but the number of fungal colonies were not different among the groups. Our results suggest that small increased rearing water temperature and lowered rearing density could potentially reduce pathogens in farming frogs.

• Korean Journal of Veterinary Service
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• v.31 no.4
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• pp.547-554
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• 2008

Bacteriospermia is a frequent finding in fresh boar semen and can result in detrimental effects on semen quality and longevity. The objectives of this study was to evaluate types of bacterial contaminants in porcine fresh semen and the reducing effect of antibiotic and density gradient with percoll on the bacterial contaminants. Fresh semen was collected by gloved-hand method into a pre-warmed($37^{\circ}C$) thermostable bottle, and was inoculated onto blood agar and MacConkey agar, respectively. After incubated for 48 hour, 7.5% $CO_2$ at $37^{\circ}C$, bacterial colonies were selected and identified by Gram staining, oxidase test, catalase test and finally identified using API kits and Vitek system. Aerobic culture yielded a variety of bacteria from different genera. The most prevalent contaminant of fresh semen were Leclecia adecarboxylata, Acineobacter banmanni, Staphylococcus epidermidis, Staphylococcus cohni spp urealyticus, Proteus mirabilis. Most of identified bacteria were Gram(-) and non-pathogenic bacteria. It seems that bacterial contaminants in fresh semen were seem originated from multiple sources at the stud/farm, and were from animal and non-animal origins. Gentamicin treatment did not eliminate the bacterial contaminants completely but 3 step-density gradient with percoll completely removed the bacterial contaminants in fresh semen. Therefore, future study is necessary to prove that density gradient method with percoll can eliminate bacteria in fresh semen without significantly affecting sperm viability or function.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.349-356
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• 2012

Eicosanoid mediates various cellular immune responses in insects. This study aimed to discover its novel action on the modulation of hemocyte populations in response to an immune challenge. Upon bacterial challenge, the last instar larvae of the beet armyworm, Spodoptera exigua, increased their total hemocyte density in 2 h, and then decreased it to a basal hemocyte density level. This rapid increase in total hemocyte density was explained by an increase of plasmatocyte and spherulocyte densities. When larvae were treated with dexamethasone (a specific phospholipase $A_2$ ($PLA_2$) inhibitor), they did not show any increase in hemocyte density in response to bacterial challenge. However, the addition of arachidonic acid (a catalytic product of $PLA_2$) to larvae treated with dexamethasone recovered the up-regulation of hemocyte density in response to bacterial infection. Among eicosanoid, cyclooxygenase (COX), but not lipoxygenase (LOX), products seemed to mediate the increase of hemocyte density in response to bacterial infection because naproxene (a COX inhibitor) inhibited the hemocyte density increase, though esculetin (a LOX inhibitor) did not. Prostaglandin $E_2$, a COX product, significantly increased the hemocyte density even without bacterial infection. These results suggest that eicosaniod mediates a rapid increase in total hemocyte density in response to immune challenge.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.60-66
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• 1988

Dynamics of bacterial communities and its colonization under aerobic gemp retting were observed in air lift fermentor as a closed system, unlike conventional hemp retting as an open system. Dried hemp which was harvested in both 1986 and 1987 was retted at room temperature. Predominant community was facultatively anaerobic Gram-negative rods, and its density was increased from $3.0\times 10^{7}$ cells/ml to $9.0\times 10^{8}$ cells/ml. The density of facultatively nanerobic Gram-positive fods was maintained at the lovel of $5.0\times 10^{6}$ cells/m, and this Gram-positive bacterial community was not participated in retting. In the Gram-negative bacterial community during the retting, five types of colonieswere developed at early stage of pH7.0-8.0, and thereafter, only three types were colonized till later stage, shich were identified as pectolytic strain Erwinia salicis, Erwinia tracheiphila and Enterobacter agglomerans. A community of facultatively Gram-negative rods was mainly proliferated in stems and dispersed into liquor after 6-8 hours. Retting was terminated within 70-80 hours.

• The Plant Pathology Journal
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• v.27 no.4
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• pp.333-341
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• 2011

Two antifungal bacteria were selected from forest soils during the screening of microorganisms antagonistic to Cylindrocarpon destructans, a cause of ginseng root rot. The antifungal bacteria were identified as Bacillus subtilis (I4) and B. amyloliquefaciens (yD16) based on physiological and cultural characteristics, the Biolog program, and 16S rRNA gene sequencing analyses. Antagonistic activity of both bacterial isolates to C. destructans increased with increasing temperature. More rapid starch hydrolytic activity of the bacteria was seen on starch agar at higher temperatures than at lower temperatures, and in the higher density inoculum treatment than in the lower density inoculum treatment. The bacterial isolates failed to colonize ginseng root the root tissues inoculated with the bacteria alone at an inoculum density of $1{\times}10^6$ cfu/ml, but succeeded in colonizing the root tissues co-inoculated with the bacteria and C. destructans. Scanning electron microscopy showed that the pathogen was damaged by the low-density inoculum treatment with the bacterial isolates as much as by the high-density inoculum treatment. Both bacterial isolates were more effective in reducing root rot when they were treated at a concentration of $1{\times}10^6$ cfu/ml than at $1{\times}10^8$ cfu/ml. Also, only the former treatment induced prominent wound periderm formation, related to structural defense against pathogen infection. The results suggest that the bacterial antagonists may have high potential as biocontrol agents against ginseng root rot at relatively low-inoculum concentrations.

• Korean journal of applied entomology
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• v.19 no.4 s.45
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• pp.199-202
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• 1980

In order to investigate the relationship among the occurrence of bacterial leaf blight, amount of nitrogen application and planting density, a field experiment was carried out with factorial combinations of N levels (7.5, 15, 30kg/10a) and planting densities (10\times20,\;15\times30,\;20\times40cm). The results obtained in this study were; (1) The incidence of bacterial leaf blight was increased with increase of nitrogen application; (2) In double amount of nitrogen application (30kg/10a), the incidence of bacterial leaf blight was higher, regardless of planting density; (3) The incidence of bacterial leaf blight in Standard nitrogen application was significantly higher $(R=0.94^{**})$ than at $15\times30cm$ density and $20\times40cm$ planting density.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.1-10
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• 2004

Many bacteria monitor their population density and control the expression of specialized gene sets in response to bacterial cell density based on a mechanism referred to as quorum sensing. In all cases, quorum sensing involves the production and detection of extracellular signaling molecules, auto inducers, as which Gram-negative and Gram-positive bacteria use most prevalently acylated homoserine lactones and processed oligo-peptides, respectively. Through quorum-sensing communication circuits, bacteria regulate a diverse array of physiological functions, including virulence, symbiosis, competence, conjugation, antibiotic production, motility, sporulation, and biofilm formation. Many pathogens have evolved quorum-sensing mechanisms to mount population-density-dependent attacks to over-whelm the defense responses of plants, animals, and humans. Since these AHL-mediated signaling mechanisms are widespread and highly conserved in many pathogenic bacteria, the disruption of quorum-sensing system might be an attractive target for novel anti-infective therapy. To control AHL-mediated pathogenicity, several promising strategies to disrupt bacterial quorum sensing have been reported, and several chemicals and enzymes have been also investigated for years. These studies indicate that anti-quorum sensing strategies could be developed as possible alternatives of antibiotics.