• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.367-373
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• 2021

The antimicrobial resistance of Staphylococcus spp. and Gram negative strains present in air samples from waste sorting facilities was assessed. Phenotypic studies have revealed a high percentage of strains of Staphylococcus spp. resistant to methicillin. Genotypically and by RT-PCR, it was found that the mecA gene usually associated with methicillin resistance was present in 8% of the Staphylococcus strains isolated. About 30% of the Gram negative strains from the same samples also displayed resistance to meropenem and 79% of these were resistant to multiple antibiotics from different classes, namely cephalosporins and β-lactams. The results suggest that in professional activities with high levels of exposure to biological agents, the quantification and identification of the microbial flora in the work environment, with the determination of the presence of potential agents displaying multi-resistances is of relevance to the risk assessment. The personal protection of workers is particularly important relevance in these cases, since many of the strains that exhibit multi-resistance are potential opportunistic agents.

• Biomolecules & Therapeutics
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• v.7 no.1
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• pp.44-53
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• 1999

The resistant strains due to the extended-spectrum $\beta$-lactamase (ESBL) were susceptible to cefatrizine combined with clavulanic acid. The purpose of this study was to evaluate the in vitro and in vivo antibacterial activities of cefatrizine/clavulanic acid (CTRZ/CV) combination at a ratio of 2 : 1 in comparison with cefaclor (CCLO), cefuroxime (CRXM), cefuroxime axetil (CRXMA) and amoxicillin/clavulanic acid (AMXCCV). CTRZ/CV showed good activity against laboratory strains of gram-positive and gram-negative bacteria and exhibited excellent antibacterial activity against $\beta$-lactamase-producing strains. The bactericidal activity of CTRZ/CV was superior to that of CCLO and CRXM, and almost equal to that of AMXCCV against the $\beta$-lactamase-producing strains. The in vitro results were substantiated. by in vivo mouse experimental infection studies with $\beta$-lactamase-producing and non-producing strains. In mixed experimental infection due to $\beta$-lactamase-producing and non-producing strains, the therapeutic efficacy of CTRZ/CV was superior to that of CTRZ, CCLO, CRXMA and AMXCCV. In respiratory tract infection in mice due to Klebsiella pneumoniae EB4O, CTRZ/CV was more erective than CCLO, CRXMA and AMXCCV and also more efficacious than CCLO, CRXMA and AMXCCV in urinary tract infection in mice due to Escherichia coli EB13. These results indicate that CTRZ/CV is a useful drug for the treatment of infection caused by $\beta$-1actamase-producing strains including ESBL-producing strains.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.309-315
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• 1996

Selective breeding and hybridization were attempted to improve shiitake(Lentinus edodes) strains for bed-log cultivation, and the results obtained are as follows. 1. Thirty five strains collected in Korea and abroad were cultivated for one generation(five years) and fruit body yields were estimated by the amounts produced from $1m^3$ of oak tree(Quercus mongolica) logs. Thus, three high-temperature type strains including FRI 177 showing productivity of $139kg/m^3log$, two mid-temperature type strains including FRI 188 of $120kg/m^3log$, and seven low-temperature type strains including FRI 187 of $96kg/m^3log$ were selected as superior strains. 2. Twelve hybrid strains confirmed as independent strains through indoor-test with hybrid strains made by Di-mon mating method were cultivated for five years(one generation). Among them, FRI 182 and FRI 184 were turned out to be superior strains. FRI 182 of high-temperature type showed the yield of 108kg per $1m^3logs$ and FRI 184 of low-temperature type produced $103kg/m^3log$. 3. There were no significant differences in productivity among high-, mid- and low-temperature types, but some differences appeared among strain groups. The correlation was not shown in productivities between bed-log and sawdust cultivations.

• YAKHAK HOEJI
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• v.39 no.2
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• pp.131-136
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• 1995

Clinically isolated bacterial strains resistant to almost of all the clinically superior .betha.-lactam antibiotics can be used to screen the promising ones among the newly synthesized $\beta$-lactam antibiotics. To select the resistant strains, the susceptibility of 389 strains of S. aureus, 144 strains of coagulase negative staphylococci, 509 strains of E. coli, 115 strains of E. cloacae and 187 strains of P. aeruginosa to methicillin, ampicillin, piperacillin and gentamicin was determined. The susceptibility of 19 bacterial strains selected through the first screening to cefixime, cefotiam, cefotaxime, flomoxef, cepfirome, cefdnir, SCE-2787, panipenem and imipenem was determined. Four strains of S. aureus finally selected have high degree of resistance to almost of all $\beta$-lactam antibiotics used and also produce $\beta$-lactamases. These 4 strains of S. aurues can be used to screen effectively the promising $\beta$-lactam antibiotics among the numerous numbers of the newly synthesized $\beta$-lactam antibiotics.

• Plant Resources
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• v.1 no.2
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• pp.98-104
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• 1998

The effects of basal media, sucrose and phytohormone concentrations, and gelling agent combinations on in vitro frond proliferation of Lemna gibba G3 and 24 additional Lemna gibba strains were examined. Frond proliferation was equivalent on Schenk and Hidebrand. Murashige and Skoog. Nitsch and Nitsch, and Gamborg's B5 media and poor on murashige and Skoog medium in the absence of benzyladenine. With the addition of benzyladenine, Schenk and Hildebrand and Gamborg's B5 Were superior and equivalent. The addition of benzuyladenine increased equally frond proliferation at either 1 or $10{\mu}M$, however at $10{\mu}M$ fronds were severely curled or fused. Benzyladenine and thidiazuron suppressed root growth but kinetin was found to greatly enhance root growth. Gibberellic acid inhibited frond proliferation. Frond proliferation was significantly different on the four sucrose concentrations of 0, 1, 3, and 5% Among them, 3% sucrose was found to be superior. The reduced frond size observed in cultures grown on 8% sucrose could be explained by showing medium osmotic potential in excess of frond water potential. Gell agents also varied significantly in their ability to promote frond proliferation with 0.25% Gelrite or a mixture of 0.15% Gelrite and 0.4% agar. Proliferation of 25 Lemna gibba strains on medium neat optimal for Lemna gibba G3 showed a six-fold variation across strains with Lemna gobba G3 placing in the top 5 fastest proliferating strains.

• International Journal of Industrial Entomology and Biomaterials
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• v.46 no.2
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• pp.55-59
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• 2023

One of the necessary conditions for the mass production of the edible insect, the white-spotted flower chafer Protaetia brevitarsis seulensis (Kolbe), is to breed a strain with excellent egg-laying ability. To identify external morphological traits related to egg-laying ability, we investigated the effects of the weight, length, and width of female adults on egg production. Correlation and multiple regression analyses revealed a positive correlation between the weight of female adults and egg production. This study suggests that selection of heavier females is a good strategy for breeding strains with superior egg-laying characteristics. The results of this study will serve as important foundational data for future breeding of superior strains.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.422-425
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• 2001

For isolating and identifying Bifidobacterium spp. originating from Korea, feces were sampled from healthy Korean infants nursery school and postpartum care center. Through the use of gram staining and microscopic examination for cell morphology, 87 bacterial strains presumed to be the Bifidobacterium strains were isolated from 59 Koreans. To identify the Bifidobacterium strains at the genus level, these bacteria were then analyzed using the TLC method. As a result, 29 of the isolated strains were confirmed as members of the genus Bifidobacterium. 29 Bifidobacterium strains were tested acid, bile salts and oxygen tolerance and investigated antioxidative effect specially. And determined the superiority of 5 strains out of 29 Bifidobacterium strains. Finally, the selected bifidobacterium was identified with using designed 16S-ITS rDNA primer.

• The Korean Journal of Mycology
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• v.47 no.2
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• pp.173-179
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• 2019

Sawdust cultivation of Lentinula edodes has been increasing in Korea. Fourteen strains were used to develop the best varieties of L. edodes, and hybridization was carried out by monohybrid cross. The number of hybridized strains was 1,638 among 3,100 combinations. They were cultivated on sawdust medium, and fruiting bodies were formed in 364 strains. Among them, 65 strains were selected as superior candidate strains based on the shape and size of the fruiting bodies. Forty strains formed fruiting bodies without lamellae structure. The shape of the stipe was cylindrical (255 strains), thick to lower part (15 strains), and thick to upper part (94 strains). By the combinations of 2462 n1-10 and 3420 n1-10, 2462 n1, 2462 n2, 2462 n10, and 3420 n3 were selected as excellent monokaryotic strains. These strains were considered to be superior monokaryotic strains that could be used for hybrid breeding.

• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.86-91
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• 2000

The purpose of this was to investigate the degradation efficiency of phenol compounds(catechol, ferulic acid, protocatechuic acid, syringic acid, vanillic acid) by Streptomyces halstedii scabies SAI-36, Streptomyces avendulas SA2-14, and Strptomyces badius(ATCC 39117, control group). The results were as follows: Catechol showed the degradation efficiency that is lower than 50% in three strains. Ferulic acid and vanillic acid showed high degradation efficiency of 98.8% and 94.5% respectively by Streptomyces lavendulas SA2-14. protocatechuic acid and syringicacid showed high degradation efficiency of 89.6% and 77.9%. The degradation efficiency of catechol by Streptomyces halstedii scabies SAI-36, Streptomyces lavendulas SA2-14 and Streptomyces badius(ATCC 39117) was low as 49.2%, 40.2% and 20.2% respectively. But the degradation of other phenolic compoumds except catechol by Streptomyces laven-dulas SA2-36 and Streptomyces badius(ATCC 39117). The results demonstrated that two experimental strains are superior ability to control group in degradation of phenol compounds and Streptomyces lavendulas SA2-14 was superior of two experimental strain. This results were consistent with previous research results that Streptomyces lavendulas SA2-14 was the best strain in degradation ability for lignin, decoloration abilities for variousdyes, and various enzyme production abilities. Therefore, it is suggested that lignin can be used as a indicator when selecting Actinomycetes for degradation of non-degradable materials such as phenol compounds.

• The Korean Journal of Mycology
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• v.37 no.2
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• pp.173-180
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• 2009

This study was carried out to obtain basic data on mycelial growth characteristics for an artificial cultivation of Volvariella volvacea. Twelve URP primers were used to assess genetic relationship of V. volvacea and its result was divided into two groups. But there was nothing different in morphological characteristics in V. volvacea. Among five kinds of mushroom media, MCM medium was selected as the favorable culture medium. The optimal range of temperature and pH for mycelial growth on V. volvacea were 35oC and pH 6~8, respectively. Carbon sources had not an effect on 10 strains of V. volvacea, and nitrogen source for the optimum mycelial growth was yeast extract. Also, we selected GMVV 79004 as a superior strain of 10 strains V. volvacea based on the mycelial growth and yield.