• Journal of Veterinary Clinics
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• v.41 no.1
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• pp.8-17
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• 2024

This study was conducted to explore the efficacy of bee venom as a treatment for mastitis and to determine the optimal dosage and treatment period. When 6 mg or 12 mg of bee venom was administered to each experimental quarter of mastitis in dairy cow, the clinical symptoms in the 12 mg quarter were noticeably improved compared to those in the 6 mg quarter. There was no significant difference in the somatic cell count (SCC) in the milk between normal and mastitis quarters between the 6 and 12 mg doses, but there was a steady decrease in the 12 mg-treated quarter (p = 0.34). To determine the treatment period, bee venom was administered for 2, 4, and 7 days. After administering 12 mg of bee venom for 7 days, the SCC in the milk was compared before 6 days and after 7 days, and the SCC was significantly decreased to less than 100,000 SC/mL after 7 days (p = 0.01). In addition, to investigate the efficacy of bee venom, the minimum inhibitory concentration for S. aureus, E. coli, and coagulase negative staphylococci was measured, and the results showed that Gram-positive bacteria were more sensitive to bee venom than Gram-negative bacteria, and treatment for Gram-negative bacteria was limited. As a result of this study, it was confirmed that a dose of 12 mg of bee venom and a treatment period of more than 7 days were required to treat mastitis, and that treatment with bee venom alone against Gram-negative bacteria was negative.

• Archives of Pharmacal Research
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• v.12 no.4
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• pp.259-262
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• 1989

The reaction of the sodium salts of 4-methoxy and 4, 7-dimethoxy 6-hydroxy benzofuran-5-carboxylic acid with ethyl chloroformate yields the corresponding dicarbethoxy derivatives. The N-substituted amides were obtained by treating the latter compounds with amines. The corresponding hydrazides were synthesized by the reaction of hydrazine hydrate on the dicarbethoxy derivatives which spontaneously cyclized to 5-substituted-2, 3- dihydro-1, 3, 4, -oxadiazol-2-one. Also the reaction with phenyl hydrazine has been studied. The dicarbethoxy derivatives and N-substituted amides were tested against Gram positive and Gram negative bacteria in vitro. Most of the compounds posses moderate or slight activity against Gram positive bacteria.

• Journal of Microbiology and Biotechnology
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• v.21 no.6
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• pp.545-555
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• 2011

The diversity elucidation by amplified ribosomal DNA restriction analysis and 16S rDNA sequencing of 96 associative diazotrophs, isolated from the feeder roots of tea on enriched nitrogen-free semisolid media, revealed the predominance of Gram-positive over Gram-negative bacteria within the Kangra valley in Himachal Pradesh, India. The Gram-positive bacteria observed belong to two taxonomic groupings; Firmicutes, including the genera Bacillus and Paenibacillus; and Actinobacteria, represented by the genus Microbacterium. The Gram-negative bacteria included ${\alpha}$-Proteobacteria genera Brevundimonas, Rhizobium, and Mesorhizobium; ${\gamma}$-Proteobacteria genera Pseudomonas and Stenotrophomonas; and ${\beta}$-Proteobacteria genera Azospira, Burkholderia, Delftia, Herbaspirillum and Ralstonia. The low level of similarity of two isolates, with the type strains Paenibacillus xinjiangensis and Mesorhizobium albiziae, suggests the possibility of raising species novum. The bacterial strains of different phylogenetic groups exhibited distinct carbon-source utilization patterns and fatty acid methyl ester profiles. The strains differed in their nitrogenase activities with relatively high activity seen in the Gramnegative strains exhibiting the highest similarity to Azospira oryzae, Delftia lacustris and Herbaspirillum huttiense.

• Mycobiology
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• v.35 no.4
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• pp.210-214
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• 2007

Antibacterial and antifungal activities of liquid culture filtrate, water and ethanol extract (solid culture) of Stereum ostrea were evaluated against 5 bacteria and 3 plant pathogenic fungi. To determine the minimal inhibitory concentration (MIC), we studied $5{\sim}300\;mg/ml$ concentrations against bacteria and fungi separately. The MIC was 10 mg/ml for Bacillus subtilis and 40 mg/ml for Colletotrichum gloeosporioides and Colletotrichum miyabeanus. Liquid culture filtrate was more effective against Gram positive than Gram negative bacteria, and Staphylococcus aureus was the most inhibited (20.3 mm) bacterium. Water and ethanol extracts were effective against both Gram positive and Gram negative bacteria, and water extract was better than ethanol extract. In water and ethanol extract, inhibition zones were 23.6 and 21.0 mm (S. aureus) and 26.3 and 22.3 mm (Pseudomonas aeruginosa), respectively. For plant pathogenic fungi, the highest and lowest percent inhibition of mycelial growth (PIMG) was found 82.8 and 14.4 against C. miyabeanus and Botrytis cinerea in liquid culture filtrate, respectively. In water extract, the PIMG was found to be the highest 85.2 and lowest 41.7 for C. miyabeanus and C. gloeosporioides, respectively. The inhibitory effect of ethanol extract was better against C. miyabeanus than C. gloeosporioides and B. cinerea. Among 3 samples, water extract was the best against tested pathogenic fungi. This study offers that the extracts isolated from S. ostrea contain potential compounds which inhibit the growth of both bacteria and fungi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.293-298
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• 1995

Antimicrobial effect of tea extracts from green tea(steamed, roasted), oolong tea and black tea was investigated. Minimal inhibitory concentration(MIC) of tea extraxcts against 9 well known strains of foodborne pathogenic bacteria such as the Gram positive and Gram negative bacteria was determined at 37$^{\circ}C$. Significant antimicrobial activity was observed in the steamed green tea and the roasted green tea of the water-soluble fraciton, and the steamed green tea of the methanol-soluble fraction, and the steamed green tea, roasted green tea and the oolong tea of the crude catechin fraction. The MIC of these extracts against B. subtillis were 700$\mu\textrm{g}$/ml, 500$\mu\textrm{g}$/ml and 120 $\mu\textrm{g}$/ml, respectively. The crude catechin fraction possessed greater antimicrobial activity than did the other fractions. Among tea extracts, extracts of steamed green tea, roasted green tea and oolong tea showed higher antimicrobial activity than them of black tea. The MIC of the crude catechin fraction obtained from tea extracts against Gram-positive bacteria such as M. Iuteus, B. subtillis and S. mutans were 30~50$\mu\textrm{g}$/ml, 120~240$\mu\textrm{g}$/ml and 120~180$\mu\textrm{g}$/ml, and against Gram-negative bacteri such as e. aerogenes and V. parahaemolyticus were 50~60$\mu\textrm{g}$/ml and 60~70$\mu\textrm{g}$/ml in the broth medium, respectively. Especially, the MIC to Streptococcus mutans which has known as a causative bacteria of a decayed tooth were 120$\mu\textrm{g}$/ml, 140$\mu\textrm{g}$/ml, 180$\mu\textrm{g}$/ml and above 1,000$\mu\textrm{g}$/ml in steamed green tea, roasted green tea, oolong tea and black tea, respectively. Tea extracts had strong growth inhibition activity against foodborne pathogenic and dental bacteria.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.7
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• pp.1052-1061
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• 2019

Objective: This study was conducted to identify duck liver-expressed antimicrobial peptide 2 (LEAP-2) and demonstrate its antimicrobial activity against various pathogens. Methods: Tissue samples were collected from 6 to 8-week-old Pekin ducks (Anas platyrhynchos domesticus), total RNA was extracted, and cDNA was synthesized. To confirm the duck LEAP-2 transcript expression levels, quantitative real-time polymerase chain reaction was conducted. Two kinds of peptides (a linear peptide and a disulfide-type peptide) were synthesized to compare the antimicrobial activity. Then, antimicrobial activity assay and fluorescence microscopic analysis were conducted to demonstrate duck LEAP-2 bactericidal activity. Results: The duck LEAP-2 peptide sequence showed high identity with those of other avian species (>85%), as well as more than 55% of identity with mammalian sequences. LEAP-2 mRNA was highly expressed in the liver with duodenum next, and then followed by lung, spleen, bursa and jejunum and was the lowest in the muscle. Both of LEAP-2 peptides efficiently killed bacteria, although the disulfide-type LEAP-2 showed more powerful bactericidal activity. Also, gram-positive bacteria was more susceptible to duck LEAP-2 than gram-negative bacteria. Using microscopy, we confirmed that LEAP-2 peptides could kill bacteria by disrupting the bacterial cell envelope. Conclusion: Duck LEAP-2 showed its antimicrobial activity against both gram-positive and gram-negative bacteria. Disulfide bonds were important for the powerful killing effect by disrupting the bacterial cell envelope. Therefore, duck LEAP-2 can be used for effective antibiotics alternatives.

• Biodesign
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• v.6 no.4
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• pp.96-99
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• 2018

The gram-positive bacterium Staphylococcus aureus is a common cause of abscesses, sinusitis and food poisoning. The emergence of antibiotic-resistant strains has caused significant clinical issues worldwide. The HslU-HslV complex was first identified as a prokaryotic homolog of eukaryotic proteasomes. HslU is an unfoldase that mediates the unfolding of the substrate proteins, and it works with the protease HslV in the complex. To date, the protein complex has been mostly studied in gram-negative bacteria. In this study, we report the purification and crystallization of the full-length HslU from S. aureus. The crystal diffracted X-rays to a $3.5{\AA}$ resolution, revealing that the crystals belong to space group $P2_1$, with unit cell parameters of a = 166.5, b = 189.6, $c=226.6{\AA}$, and ${\beta}=108.1^{\circ}$. We solved the phage problem by molecular replacement using the structure of HslU from Haemophilus influenzae as a search model. The cell content analysis with this molecular replacement solution revealed that 24 molecules are contained in the asymmetric unit. This structure provides insight into the structural and mechanistic difference of the HslUV complex of gram-positive bacteria.

• KSBB Journal
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• v.26 no.6
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• pp.543-551
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• 2011

Bacterial antibiotic resistance is a real and growing problem for both Gram positive and Gram negative bacterial pathogens in the hospital setting. Among Gram negative bacteria, the ubiquitous bacterium Pseudomonas aeruginosa is a particular concern in immunocompromised and burn patients. The present study evaluated antibacterial activity and efficacy of a Korean herbal medicine against eight multi-drug resistant clinical isolates of P. aeruginosa (0225, 0254, 0347, 0826, 1113, 1378, 1731, and 2492) isolated at Daegu Catholic University Hospital. Methanol extracts of Galla rhois (5 and 10 mg/mL) displayed inhibition diameters for isolate 2492 of 10 and 12 mm, respectively, in a conventional disc diffusion assay. In seven kinds of Korean herbal medicines, increased inhibitory power of Lonicera japonica, Gardenia jasminoides, Galla rhois, and Scultellaria baicalensis was evident with the fermentation of six kinds of lactic acid bacteria. Three lactic acid bacteria (Lactobacillus plantarum subsp. plantarum KCTC 3108, L. casei KCTC 3109, and L. fermentum KCTC 3112) were identified as excellent strains for the production of antibacterial materials. In the six Korean herbal medicine extracts, strong inhibitory activity of fermented Forsythia suspensa, Glycyrrhizae radix, Lycium chinense, Platycodon grum, and Schizandra chinensis with five kinds of lactic acid bacteria was evident for seven multi-drug resistant P. aeruginosa isolates.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.783-788
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• 2016

Agricultural management of paddy soil depends on the effects of soil microbial activities. The present study evaluated the soil microbial community of 25 paddy soils in Gyeongnam Province by fatty acid methyl ester (FAME). The average of microbial communities in paddy soils were 32.2% of total bacteria, 16.7% of Gram-negative bacteria, 12.9% of Gram-positive bacteria, 2.0% of actinomycetes, 14.9% of fungi, and 1.3% of arbuscular mycorrhizal fungi. The communities of total bacteria (34.9%) and Gram-negative bacteria (19.4%) in soils with $30{\sim}35g\;kg^{-1}$ of organic matter were significantly larger than those in soils with other organic matter levels. However, soils with $20{\sim}30g\;kg^{-1}$ of organic matter had significantly low ratio of cy17:0 to $16:1{\omega}7c$ and cy19:0 to $18:1{\omega}7c$ as compared with soils with $30{\sim}35g\;kg^{-1}$ of organic matter, indicating microbial stress decreased (p < 0.05). In principal component analyses of soil microbial communities, Gram-negative bacteria should be considered as a potential responsible factor for the obvious microbial community differentiation that was observed between the two different organic matter levels in paddy fields. Thus, soils containing $20{\sim}30g\;kg^{-1}$ of organic matter were responsible for strong effect on microbial biomass and stress in paddy fields.

• Pediatric Infection and Vaccine
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• v.19 no.3
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• pp.131-140
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• 2012

Purpose : This study was performed to identify the etiologic agents and antimicrobial susceptibility patterns of organisms responsible for bloodstream infections in pediatric cancer patients for guidance in empiric antimicrobial therapy. Methods : A 5-year retrospective study of pediatric hemato-oncologic patients with bacteremia in Seoul National University Children's Hospital, from 2006 to 2010 was conducted. Results : A total of 246 pathogens were isolated, of which 63.4% (n=156) were gram-negative, bacteria 34.6% (n=85) were gram-positive bacteria, and 2.0% (n=5) were fungi. The most common pathogens were Klebsiella spp. (n=61, 24.8%) followed by Escherichia coli (n=31, 12.6%), coagulase-negative staphylococci (n=23, 9.3%), and Staphylococcus aureus (n=22, 8.9 %). Resistance rates of gram-positive bacteria to penicillin, oxacillin, and vancomycin were 85.7%, 65.9%, and 9.5%, respectively. Resistance rates of gram-negative bacteria to cefotaxime, piperacillin/tazobactam, imipenem, gentamicin, and amikacin were 37.2%, 17.1%, 6.2%, 32.2%, and 13.7%, respectively. Overall fatality rate was 12.7%. Gram-negative bacteremia was more often associated with shock (48.4% vs. 11.9%, P<0.01) and had higher fatality rate than gram-positive bacteremia (12.1% vs. 3.0%, P=0.03). Neutropenic patients were more often associated with shock than non-neutropenic patients (39.6 % vs. 22.0%, P=0.04). Conclusion : This study revealed that gram-negative bacteria were still dominant organisms of bloodstream infections in children with hemato-oncologic diseases, and patients with gram-negative bacteremia showed fatal course more frequently than those with gram-positive bacteremia.