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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Microbiology and Biotechnology Letters
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Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
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Volume & Issues
Volume 40, Issue 4 - Dec 2012
Volume 40, Issue 3 - Sep 2012
Volume 40, Issue 2 - Jun 2012
Volume 40, Issue 1 - Mar 2012
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Analysis of Genomic Diversity of Endophytic Fungal Strains Isolated from the Roots of Suaeda japonica and S. maritima for the Restoration of Ecosystems in Buan Salt Marsh
You, Young-Hyun ; Yoon, Hyeokjun ; Seo, Yeonggyo ; Kim, Miae ; Shin, Jae-Ho ; Lee, In-Jung ; Choo, Yeon-Sik ; Kim, Jong-Guk ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 287~295
DOI : 10.4014/kjmb.1207.07025
Eighty-four endophytic fungal strains were isolated and identified from the roots of halophytes collected in Buan salt marsh. All halophyte samples, such as Suaeda japonica, and Suaeda maritima were isolated from Buan salt marsh. All endophytic fungi isolated were analyzed by sequences of internal transcribed spacer (ITS) containing ITS1, 5.8s and ITS2 region. All endophytic fungi expressed that fungal strains belong to eight orders; Pleosporales (45%), Eurotiales (27%), Incertae sedis (11%), Dothideales (6%), Capnodiales (5%), Hypocreales (5%), and Agaricales (1%). All endophytic fungi were confirmed at the genus level of Ascomycota and Basidiomycota, containing Alternaria, Ascomycota, Aspergillus, Aureobasidium, Cladosporium, Eupenicillium, Fusarium, Gibberella, Hypocrea, Lewia, Macrophoma, Penicillium, Peyronellaea, Phoma, Pleospora, Pleosporales, Pseudeurotium, Schizophyllum, and Talaromyces. Alternaria (21%) and Penicillium (13%) were the dominant endophytic fungal strains. In this study, endophytic fungal strains analyzed from S. japonica and S. maritime, Alternaria (21%), and Penicillium (13%) of Pleosporales and Eurotiales in halophytes were very abundant.
-Amyalse of Bacillus licheniformis YB-1234 Isolated from the Fermented Soybean of a Korean Buddhist Temple
Lee, Eun Ji ; Yoon, Ki-Hong ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 296~302
DOI : 10.4014/kjmb.1210.10001
A bacterial strain was isolated from soybean paste fermented in a Korean Buddhist temple as a producer of the extracellular thermostable
-amylase. The isolate YB-1234 has been identified as Bacillus licheniformis on the basis of its 16S rDNA sequence, morphology and biochemical properties. A gene encoding the thermostable
-amylase of B. licheniformis YB-1234 was cloned into Escherichia coli and its nucleotide sequence was determined. The deduced amino acid sequence of
-amylase was very highly homologous to those of the thermostable
-amylases of B. licheniformis belonging to the glycosyl hydrolase family 13. The
-amylase produced by recombinant E. coli carrying the
-amylase gene exhibited maximal activity at pH 6.0, identical to
-amylase in the culture filtrate of B. licheniformis, while the temperature profile was somewhat different between the two. Particularly,
-amylase produced from B. lcheniformis is much more thermostable than that from recombinant E. coli. The predominant products resulting from the
-amylase hydrolysis were glucose, maltose and maltotriose for maltotetraose and maltohexaose.
Isolation and Characterization of a Feather Degrading Alkalophilic Streptomyces sp. TBG-S13A5 and its Keratinolytic Properties
Indhuja, Selvaraj ; Shiburaj, Sugathan ; Pradeep, Nediyaparambu Sukumaran ; Thankamani, Vaidyanathan ; Abraham, Teruvath Koshy ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 303~309
DOI : 10.4014/kjmb.1205.05015
Keratinases are of particular interest because of their action on insoluble keratins and generally on a broad range of protein substrates. Alkalophilic and neutrophilic actinomycete strains isolated from different soil samples, rich in keratinaceous substances were screened for keratinolytic activity. An alkalophilic isolate, TBG-S13A5, was found to possess good keratinolytic activity and was able to utilize feather as the sole carbon and nitrogen source. TBG-S13A5 exhibited an off-white aerial mass color with a rectus-flexibilis type of spore chain. The morphological, microscopical and biochemical characters were comparable with that of Streptomyces albidoflavus. Fatty acid methyl ester profiling (FAME) and 16S rDNA sequence analysis confirmed its identity as a strain of S. albidoflavus. Under submerged fermentation conditions, maximum protease production was recorded on the
day of incubation at
, using basal broth of pH 9.0 with 0.25% (w/v) white chicken feather. This strain could affect feather degradation when the initial pH was 8 and above and maximum protease production was recorded when the initial pH was around 10.5. The effectiveness of the crude enzyme in destaining and leather dehairing were also demonstrated.
Lactococcus lactis Culture Methods for the Enhanced Depression of Inducers in Atopic Diseases
Jo, Yu-Ran ; Kang, Sang-Mo ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 310~318
DOI : 10.4014/kjmb.1205.05025
We conducted a screening and checked the cultivation methods of lactic acid bacteria, which have anti-atopic dermatitis functions, by determining the lactic acid bacteria's immune enhancement by FACS, and antimicrobial activity against Staphylococcus aureus. The increase of Tcell CD4+/CD25+/foxp3+ was bigger in Lactobacillus plantarum than Lactococcus lactis subsp. lactis (Lc. lactis) and the antimicrobacterial activity against S. aureus was the opposite. The antimicrobial activity of Lb. plantarum culture with medium containing Lc. lactis culture broth was not enhanced, but the antimicrobial activity of Lc. lactis cultured in a medium containing Lb. plantarum culture broth was enhanced. As the optimal method caltivation of Lc. lactis in a medium containing 10% of heat-killed Lb. plantarum culture broth was chosen. By this method, the antibacterial activity of the pure Lc. lactis culture increased sharply at the end of the log phase, while a restraint effect on the growth of S. aureus increased 1.29 times.
Quality Characteristics of Wheat Nuruks by Storage Conditions of Liquid Starters Using Rhizopus oryzae N174
Choi, Jeong-Sil ; Jung, Seok-Tae ; Choi, Ji-Ho ; Choi, Han-Seok ; Baek, Seong-Yeol ; Yeo, Soo-Hwan ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 319~324
DOI : 10.4014/kjmb.1205.05029
Production of liquid starters using wheat bran as a medium for Rhizopus oryzae N174 and the changes in their characteristics noted during storage were investigated in this study. The optimal culture conditions of the liquid starters were determined to be 5~15% (w/v) wheat bran and 48~72 hrs of incubation. The effects of liquid starters with different storage periods and temperatures (-18, 4, 10 and
) on the quality of wheat nuruk were evaluated. According to the results of the pH, acidity, reducing sugar and enzyme activities, it was found that liquid starter using wheat bran preserved for one day, at any temperature, is the best method of storage for seed cultures for R. oryzae N174.
Physicochemical Properties, Lactic Acid Bacteria Content and Physiological Functionalities of Korean Commercial Makgeolli
Kim, Young-Hun ; Min, Jin-Hong ; Kang, Min-Gu ; Kim, Jae-Ho ; Ahn, Byung-Hak ; Kim, Ha-Kun ; Lee, Jong-Soo ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 325~332
DOI : 10.4014/kjmb.1207.07006
The goal of this study was to characterize the physicochemical properties, lactic acid bacteria and physiological functionality of Korean commercial Makgeolli. We collected 60 kinds of raw and pasteurized Makgeolli commercially available in Korea. Their physicochemical properties, lactic acid bacteria content and physiological functionalities were determined. In the commercial raw Makgeolli, ethanol and residual sugar content ranged from 3.6% to 9.6% and 0.20% to 4.52%, respectively. Furthermore, the raw Makgeolli contained 3.50 to 101.9 mg% of amino nitrogen. In the pasteurized Makgeolli, ethanol content ranged from 4.0% to 7.0% and their residual sugar content were 0.98% to 7.57%. The raw Makgeolli contained 2.0
CFU/mL of lactic acid bacteria. Among several functionalities, the antihypertensive angiotensin I-converting enzyme inhibitory activities of EDS-14 raw Makgeolli and PWR-12 pasteurized Makgeolli were very high, at 89.9% and 87.0% respectively. The other functionalities were seen to be below 30% or not detectable. The
-Glucan contents of the raw and pasteurized Makgeolli were noted as average, at 14.1% and 14.6%, respectively.
Antioxidant Activities of Bacterial Culture Extracts Isolated from Arctic Lichens
Kim, Mi-Kyeong ; Park, Hyun ; Oh, Tae-Jin ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 333~338
DOI : 10.4014/kjmb.1207.07027
Lichens are a symbiosis between fungi, algae and cyanobacteria. Our group recently studied the antioxidant properties of some bacterial species isolated from Arctic lichens and we confirmed that they possess high antioxidant activities. In this paper, we investigated the antioxidant capacity of 5 microorganisms newly isolated from 4 Arctic lichen species, Cladonia sp., Sterocaulon sp., Umbilicaria sp. and Cetraria sp., using various solvent extractions. We carried out 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging activity test and ferric reducing antioxidant power (FRAP) assay. Also total phenolic and flavonoid content assays were performed. Among the bacterial culture extracts of the tested lichen-microorganisms, ethyl acetate extracts of Burkholderia sordidicola S5-B(T) had not only a high antioxidant activity (72.9%) when compared with the ascorbic acid used as the control (51.3%) in the DPPH assay, but also a high amount of phenolic content as well as flavonoid content. As a result, these lichen-microorganisms may be potentially useful sources of natural antioxidants.
Multiplex Reverse Transcription-PCR for Simultaneous Detection of Reovirus, Bovine Viral Diarrhea Virus, and Bovine Parainfluenza Virus during the Manufacture of Cell Culture-derived Biopharmaceuticals
Oh, Seon Hwan ; Bae, Jung Eun ; Kim, In Seop ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 339~347
DOI : 10.4014/kjmb.1210.10008
Viral safety is an important prerequisite for clinical preparations of mammalian cell culture-derived biopharmaceuticals, because numerous adventitious viruses have been contaminated during the manufacturing process. In particular, Chinese hamster ovary (CHO) cells are highly susceptible to several RNA viruses including reovirus (Reo), bovine viral diarrhea virus (BVDV), and bovine parainfluenza virus (BPIV) and there have been reports of such viral contaminations. Therefore, viral detection during the CHO cell process is necessary to ensure the safety of biopharmaceuticals against viruses. In this study, a multiplex reverse transcription (RT)-PCR assay was developed and subsequently evaluated for its effectiveness as a means to simultaneously detect Reo, BVDV, and BPIV during the manufacture of cell culture-derived biopharmaceuticals. Specific primers for Reo, BVDV, and BPIV were selected, and a multiplex RT-PCR was optimized. The sensitivity of the assay for simultaneous amplification of all viral target RNAs was
for BVDV, and
for BPIV. The multiplex RT-PCR was proven to be very specific to Reo, BVDV, and BPIV and was subsequently applied to the validation of CHO cells artificially infected with each virus. It could detect each viral RNA from CHO cells as well as culture supernatants. Therefore, it was concluded that the multiplex RT-PCR assay can be applied to detection of the adventitious viruses during the manufacture of cell culture-derived biopharmaceuticals.
Overexpression and Characterization of Bovine Pancreatic Deoxyribonuclease I in Saccharomyces cerevisiae and Pichia pastoris
Cho, Eun-Soo ; Kim, Jeong-Hwan ; Yoon, Ki-Hong ; Kim, Yeon-Hee ; Nam, Soo-Wan ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 348~355
DOI : 10.4014/kjmb.1211.11001
In the present study, we investigated the overexpression and characterization of bovine pancreatic (bp)- DNase I in Saccharomyces cerevisiae and Pichia pastoris. The bp-DNase I gene was fused in frame with the GAL10 promoter,
, and GAL7 terminator sequences, resulting in the plasmid, pGAL-
-DNaseI (6.4 kb). Also, the bp-DNase I gene was fused in frame with the AOX1 promoter,
, and AOX1 terminator sequences, resulting in the plasmid, pPEXI (8.8 kb). The recombinant plasmids, pGAL-
-DNaseI and pPEXI were introduced into S. cerevisiae and P. pastoris host cells, respectively. When the transformed yeast cells were cultured at
for 48 h in galactose or methanol medium, bp-DNase I was overexpressed and the most of activity was found in the extracellular fraction. P. pastoris transformant activity showed 45.5 unit/mL in the culture medium at 48 h cultivation, whereas S. cerevisiae transformant revealed 37.7 unit/mL in the extracellular fraction at 48 h cultivation. The enzymatic characteristics, such as DNA cleavage and half life were investigated. Treatment of the recombinant DNase I from P. pastoris induced degradation of the calf thymus DNA within 1 minute, and this DNA degradation rate was higher than that of commercial bp-DNase I (SIGMA) and the recombinant DNase I from S. cerevisiae.
Xanthan Gum Production from Hydrolyzed Rice Bran as a Carbon Source by Xanthomonas spp.
Demirci, Ahmet Sukru ; Arici, Muhammet ; Gumus, Tuncay ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 356~363
DOI : 10.4014/kjmb.1205.05023
The aim of this study was to utilize rice bran, the main waste product of paddy processing, in xanthan gum production by Xanthomonas campestris fermentation. Deffated rice bran was enzymatically hydrolyzed using cellulase, gluco-amylase, alpha-amylase and xylanase at various pHs and temperatures within 0-12 h. The highest sugar content reached at
, pH 5.5 in 6 h with 41.66%. The enzymatic hydrolysate was used as the carbon source for xanthan gum production by X. campestris NRRL B-1459 and X. campestris pv. campestris. The highest productivities obtained were 21.87 and 17.10 g/L, respectively. Viscosity measurement for the obtained xanthan gums and commercial gum was carried out in gum solutions at various pHs and temperatures. The highest viscosity was reached with 1% gum solutions at
and pH 5.5 for all gums with viscosity values of 470, 131 and 138 mPa sec, respectively. This work has provided relevant scientific information about the use of rice bran, an abundant agroindustrial residue, to produce xanthan gum.
Whitening and Anti-wrinkling Effects of Fractions from Prunus persica Flos
Lee, Jin-Young ; An, Bong-Jeun ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 364~370
DOI : 10.4014/kjmb.1207.07007
In this study, the compounds of Prunus persica Flos were extracted with 70.0% acetone and were purified using a sephadex-LH-20 column chromatography. As a result, eight fractions were isolated. For whitening effects, the tyrosinase inhibitory activity was determined to be 92.2% in Fr.-8 isolated from P. persica Flos at 1.000 ppm. The melanoma cell-originated tyrosinase inhibitory effect of Fr.-8 from P. persica Flos was approximately 63.4% at 100 ppm. The inhibitory activity on melanin synthesis by Fr.-8 isolated from P. persica Flos was about 71.7% at 100 ppm concentration. For anti-wrinkling effects, the elastase inhibition activities by Fr.-5, 7 isolated from P. persica Flos were around 71.4 and 74.5% respectively at 1,000 ppm. The collagenase inhibition activity and collagen synthesis by Fr.-8 isolated from P. persica Flos was about 80.0% at 100 ppm. All these findings suggested that the fractions of P. persica Flos have great potential as cosmeceutical ingredients with whitening and anti-wrinkling effects.
Anti-Oxidant, Anti-Melanogenic, and Anti-Inflammatory Activities of Zanthoxylum schinifolium Extract and its Solvent Fractions
Jin, Kyong-Suk ; Oh, You Na ; Park, Jung Ae ; Lee, Ji Young ; Jin, Soojung ; Hyun, Sook Kyung ; Hwang, Hye Jin ; Kwon, Hyun Ju ; Kim, Byung Woo ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 371~379
DOI : 10.4014/kjmb.1207.07023
This study was designed to explore new nutraceutical and cosmetic resources possessing biological activities from the plant kingdom. To fulfill this purpose, we analyzed the anti-oxidative, anti-melanogenic, and anti-inflammatory activities of Zanthoxylum schinifolium extract (ZSE) and its solvent fractions using in vitro assays and cell culture model systems. Three kinds of ZSE treated with methanol, ethanol, and water exhibited potent anti-oxidative activities through DPPH radical scavenging capacity, and inhibited in vitro DOPA oxidation. Furthermore, Z. schinifolium methanol extract (ZSME) inhibited the
-melanocyte stimulating hormone, which induces melanin contents in B16F10 cells. Its anti-melanogenic activity originates from the inhibition of tyrosinase enzyme activity and melanogenesis related protein expression. Moreover, lipopolysaccharide induced nitric oxide production in the RAW 264.7 cell line was also ameliorated by ZSME treatment in a dose dependent manner. Among the four solvent fractions of ZSME treated with dichloromethane, ethyl acetate, n-butanol, and water, three fractions, except water, showed significant anti-melanogenic and anti-inflammatory activities. Taken together, these results provide important new insights into Z. schinifolium, indicating that it possesses numerous biological activities such as anti-oxidative, anti-melanogenic, and anti-inflammatory activities. Therefore, it may well serve as a promising material in the field of nutraceuticals and cosmetics.
Antibacterial Properties Associated with Microorganisms Isolated from Arctic Lichens
Kim, Mi-Kyeong ; Park, Hyun ; Oh, Tae-Jin ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 380~388
DOI : 10.4014/kjmb.1207.07028
A total of 5 different polar microorganisms were isolated from Arctic lichens and their bioactive compounds were extracted from cell culture using different solvents including acetone, water, chloroform, diethylether, ethanol, ethyl acetate, methanol, and petroleum ether. The antibacterial properties of the extracts were evaluated by disk diffusion tests and minimal inhibitory concentration tests against 6 bacterial pathogens; Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Enterobacter cloacae, Pseudomonas aeruginosa and Escherichia coli. Among the extraction samples, ethyl acetate extracts of Burkholderia sordidicola S5-
(KOPRI 26644) showed the highest activity (inhibition zone, 7-10 mm; MIC value, 57.5-1000 ug/ml) against targeted bacteria. Among the various solvents used for extraction, chloroform extract exhibited the weakest, but still obvious, activity.
Evaluation of the Colonization of Lactobacillus plantarum in Mouse Gut by Terminal Restriction Fragment Length Polymorphism Analysis
Jung, Gwangsick ; Lee, Jong-Hoon ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 389~395
DOI : 10.4014/kjmb.1208.08009
T-RFLP (terminal restriction fragment length polymorphism) analysis, one of the most highly adopted culture-independent microbial community analysis methods, was applied to evaluate the colonization of probiotics in experimental animal gut. Lactic acid bacteria that exhibited cinnamoyl esterase activity were isolated from Korean fermented vegetables and identified by 16S ribosomal RNA sequence analysis. Lactobacillus plantarum KK3, which demonstrated high chlorogenic acid hydrolysis by cinnamoyl esterase activity, and acid/bile salt resistances, was cultured, freeze-dried, and fed to mice and the microbiota in their feces were monitored by T-RFLP analysis. The T-RF of L. plantarum was detected in the feces of mice after the start of administration and lasted at least 31 days after the initial 7 day feeding. T-RFLP analysis was considered a useful tool to evaluate the gut colonization of probiotic L. plantarum. In order to prove that L. plantarum was from viable cells, we reisolated L. plantarum in the feces using cinnamoyl esterase activity media as the screening step. The colonization of L. plantarum KK3 in the mouse gut was confirmed by this research.
Anti-Porcine Epidemic Diarrhea Virus (PEDV) Activity and Antimicrobial Activities of Artemisia dubia Essential Oil
Kim, Jong-Im ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 396~402
DOI : 10.4014/kjmb.1208.08011
The chemical composition, anti-porcine epidemic diarrhea virus (PEDV) activity and antimicrobial activity of Artemisia dubia essential oil were evaluated in this study. Fifty eight compounds from A. dubia essential oil were identified through analysis by gas chromatography-mass spectrometry (GC-MS). The major constituents of the oil were camphor (17.18 %), germacrene-D (15.70%), trans (
) racaryophyllene (6.79%), ene thujones (6.57%), 1, 8-cineole (5.94%) and camphene (5.08%). The essential oil was evaluated for antiviral activity against PEDV in Vero cells using a cytopathic effect (CPE) reduction method. The oils actively inhibited PEDV replication with a 50% inhibitory concentration (
) of 43.7
. The 50% cytotoxicity concentration (
) of the oils was over 100
and the derived therapeutic index was >2.3. Similar analysis of the ribavirin revealed that they have a relatively weaker efficacy when compared to the oils. The antimicrobial activity of the essential oil against 5 microorganisms was evaluated by the disc diffusion method. The essential oil exhibited antimicrobial activity against 5 tested microorganisms with a clear zone of 8-22 mm. Among the tested microorganisms, Streptococcus pyogenes was the most sensitive and Candida albicans the least. Therefore, in can be concluded that essential oils of A. dubia may have interesting applications for microbial control or the control of PEDV-derived diseases.
Antibacterial Effect of Gelatin/Ag Nanoparticle Biocomposite Prepared Using Solution Plasma Generated by Unipolar DC Power
Kim, Seong-Cheol ; Yoon, Gook-Jin ; Nam, Sang-Woo ; Lee, Sang-Yul ; Kim, Jung-Wan ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 403~408
DOI : 10.4014/kjmb.1209.09001
Gelatin/Ag nanoparticle (AgNP) biocomposite was synthesized using the solution plasma process (SPP) that has been recently introduced as an effective method for synthesis of nanoparticles. In this study, gelatin/AgNP biocomposite was synthesized using various concentrations of Ag precursor (
) and gelatin in the range of 1-5 mM and 1-3% (w/w), respectively, without using any chemical reducing agent. Physical properties of the gelatin/AgNP biocomposites were analyzed using EDS, FE-SEM, and TEM. The results indicated that spherical AgNPs with approximately 12~20 nm in diameter were synthesized successfully in the gelatin matrix by SPP. As the concentration of gelatin was increased (3%, w/w), disperse stability of AgNP was improved and micro-pores of gelatin became smaller and denser in the 3D scaffold. Bactericidal activity of the AgNPs was examined against Staphylococcus aureus and Escherichia coli by measuring zone of growth inhibition and decrease in colony forming unit (CFU). CFUs of S. aureus and E. coli were decreased approximately to 56% and 0%, respectively, by the gelatin/AgNP biocomposite, Ag5G3.
Design of Short Indolicidin Analogs with Enhanced Prokaryotic Selectivity
Shin, Song Yub ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 409~413
DOI : 10.4014/kjmb.1209.09002
Indolicidin (ID) is a 13-residue Trp-rich antimicrobial peptide (AMP) isolated from bovine neutrophils. In addition to having a high antimicrobial potency, it is also toxic to mammalian cells. To develop novel ID-derived AMPs with shorter lengths and enhanced prokaryotic selectivities (meaning potent antimicrobial activity against bacterial cells without toxicity against mammalian cells) over the parental ID, several ID analogs were designed and synthesized. Finally, 10-residue ID analogs (SI, SI-PA, SI-WF and SI-WL) with much higher prokaryotic selectivity than the parental ID were developed. Our results suggest that the hydrophobic and aromatic amino acids at the central position of the analog SI with the highest prokaryotic selectivity are important for potent antimicrobial activity, but two Pro residues do not affect antimicrobial activity. The order of prokaryotic selectivity for ID and its designed analogs was SI > SI-PA > SI-WF > SI-WL > ID > SI-WA. Taken together, our designed short ID analogs could be developed as therapeutic agents for treating bacterial infections.
Use of Nitrate and Ferric Ion as Electron Acceptors in Cathodes to Improve Current Generation in Single-cathode and Dual-cathode Microbial Fuel Cells
Jang, Jae Kyung ; Ryou, Young Sun ; Kim, Jong Goo ; Kang, Youn Koo ; Lee, Eun Young ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 414~418
DOI : 10.4014/kjmb.1210.10007
The quantity of research on microbial fuel cells has been rapidly increasing. Microbial fuel cells are unique in their ability to utilize microorganisms and to generate electricity from sewage, pig excrement, and other wastewaters which include organic matter. This system can directly produce electrical energy without an inefficient energy conversion step. However, with MFCs maximum power production is limited by several factors such as activation losses, ohmic losses, and mass transfer losses in cathodes. Therefore, electron acceptors such as nitrate and ferric ion in the cathodes were utilized to improve the cathode reaction rate because the cathode reaction is very important for electricity production. When 100 mM nitrate as an electron acceptor was fed into cathodes, the current in single-cathode and dual-cathode MFCs was noted as
mA, respectively. These values were similar to when air-saturated water was fed into the cathodes. One hundred mM nitrate as an electron acceptor in the cathode compartments did not affect an increase in current generation. However, when ferric ion was used as an electron acceptor the current increased by
mA, in the single-cathode and dual-cathode microbial fuel cells, respectively. These values, in single-cathode and dual-cathode microbial fuel cells, represent an increase of 67.1% and 17.6%, respectively. Furthermore, when supplied with ferric ion without air, the current was higher than that of only air-saturated water. In this study, we attempted to reveal an inexpensive and readily available electron acceptor which can replace platinum in cathodes to improve current generation by increasing the cathode reaction rate.
Isolation and Characterization of a Xylanolytic Bacterium, Bacillus sp. MX47
Chi, Won-Jae ; Park, Da Yeon ; Park, Jae-Seon ; Hong, Soon-Kwang ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 419~423
DOI : 10.4014/kjmb.1207.07026
A xylanolytic bacterial strain, MX47, was isolated from rotting plant matter in soil. The strain was aerobic and gram positive, and grew between pH 6.0 and 11.0. Cells were susceptible to thiostrepton and chloramphenicol. The major fatty acids (>3%) comprised 64.55% of iso-
, 22.76% of anteiso-
, and 3.92% of iso-
. The G/C content of the DNA was 44.15 mol%. The predominant respiratory quinone was menaquinone 7 (MK-7). Searches for 16S rRNA gene sequence similarity as well as phylogenetic analyses strongly suggested that the strain should be classified to the genus Bacillus. However, its biochemical characteristics, including acid production and enzyme activities, are different from those of other Bacillus strains in the same clade, and therefore, we propose the name Bacillus sp. MX47.
An Investigation of the Solubilization of Primary Sewage Sludge using Lactic Acid Bacteria Cultured in a Glucose and Yeast Extract Medium
Lee, Sang Min ; Choi, Han Na ; Shin, Jung Hun ; Lee, Eun Young ;
Microbiology and Biotechnology Letters, volume 40, issue 4, 2012, Pages 424~429
DOI : 10.4014/kjmb.1210.10010
The intention of this research was to investigate the solubilization of primary sewage sludge using lactic acid bacteria cultured in a glucose and yeast extract medium. Glucose as the carbon source and yeast extract as the source of nitrogen were chosen as an economic medium with the potential for the mass production of lactic acid bacteria. The optimal concentrations of the medium were 3% (w/v) glucose and 2% (w/v) yeast extract. In this study, in order to improve field applications for the solubilization of sludge at sewage treatment plants, a powdered form of lactic acid bacteria was produced. The optimal inoculum of the powder for the maximum efficiency of solubilization was 1% (w/v). In that condition, the SCOD value increased from 8600 (mg/L) at the beginning of experiment to 10290 (mg/L) at 96 h, with the highest solubilization rate (20.6% DDCOD) and 11.2% (SCOD). Also, the TVFAs of the lactic acid bacteria inoculation group were produced more than that of the control group. In particular, acetic acid was produced 5 times more in the experimental group than in the control group. In this research, the potential of lactic acid bacteria in the pretreatment of primary sewage sludge as a solubilizer, and as an energy source producer for microbial fuel cells was revealed.