• Journal of Life Science
• /
• v.12 no.6
• /
• pp.786-795
• /
• 2002

Three-day-old sunfower(Helianthus annuus L.) seedlings were do-rooted and incubated in the nutrient solutions that contained either deficient or sufficient boron supply, and exposure to various pH and temperatures. In the absence of boron, no adventitious roots were formed in the majority of the seedlings. Boron caused the development of numerous adventitious roots in the lower part of the hypocotyl. The low pH damage was ameliorated by the simultaneous application of calcium, implying the involvement of calcium-requiring process in overcoming proton toxicity. Borate showed a strong ameliorative effect with $Ca^{2+}$. These results suggest that the primary target of proton toxicity may be linked to a disturbance of the stability in the pectic polysaccharide network, where calcium plays a key role in plant roots. Maximum temperature for the growth of adventitious roots was $25^{\circ}C$. Although cessation of growth is the most apparent symptom of boron deficiency, exogenous ascorbate improved adventitious root growth in plants in the absence of boron. From the results it is suggested that the inhibition of adventitious root resulting from boron deficiency, low pH and temperature damage may be a consequence of disrupted ascorbate metabolism.

• Korean Journal of Food Science and Technology
• /
• v.37 no.2
• /
• pp.241-246
• /
• 2005

Effects of antimicrobial herbs on growth of tactic acid bacteria were investigated to extend shelf-life of Dongchimi, kimchi made with radishes and spices. Marta rosemary, among eight foreign and domestic herbs, showed strongest antimicrobial activity against seven kinds of lactic acid bacteria. Spices such as spring onion, garlic, and ginger showed no antimicrobial activity against lactic acid bacteria. During fermentation of Dongchimi for 6 days at $35^{\circ}C$, addition of marta rosemary inhibited acid formation, maintaining optimal pH of 3.8-4.2 throughout fermentation period, while no inhibitory effect was observed from Sambaekho (Saurus chinensis), pepper mint, and stevia. Results show shelf-life of Dongchimi was extended by addition of marta rosemary, which controlled over-production of tactic acid by inhibiting bacterial growth.

• Journal of the Korean Vacuum Society
• /
• v.6 no.1
• /
• pp.61-68
• /
• 1997

We examined the dependence of the growth of undoped InP epilayer by chloride vapor phase epitaxy on the growth temperature and on the $PCl_3$molar fraction. The growth temperature was varied from $620^{\circ}C$ to $650^{\circ}C$ and the $PCl_3$molar franction from $2.5{\times}10^{-2}$ to $4.5{\times}10^{-2}$. The undoped InP epilayer with hillock free surface was obtained at the growth temperature of $640^{\circ}C$ and at the PCl$_3$molar fraction of $3.0{\times}10^{-2}$. The surface morphology was improved with a decrease of the PCl$_3$molar fraction. The carrier concentration measured by Hall and ECV was less than $1{\times}10^{14}cm^{-3}$. The resistivity of the undoped InP epilayer, measured by using four probe method, showed a high value of <$3.0{\times}10^6{\Omega}\textrm{cm}$.

• Korean Journal of Microbiology
• /
• v.36 no.1
• /
• pp.52-57
• /
• 2000

A method for quantitative and qualitative analysis of geosmin, odorant produced by several actinomycetes and cyanobacteria, was established and optimized. The effects of environmental conditions on the growth of Phormidium sp. NIVA-CYA7 were examined and the production and release of geosmin by the species was analyzed by using the purge and trap-gas chromatographic technique. One of the major advantages of the technique established in the present study is that the preparation of sample is simpler and purge time is shorter. Under the culture conditions (pH 7.9, $20^{\circ}C$, 120-140 $\mu$E/$m^2$/s and Z8 medium), Phormidium showed growth characteristics with a lag phase for 8 days and an exponential phase for 14 days followed by a stationary phase. Reduction of inorganic nitrogen concentrations in the culture medium from 250 to 100 or 25 $\mu$M brought no significant effect on the cell growth. However, the cell growth was significantly inhibited with decreasing concentrations of inorganic phosphorus from 25 to 10 or 2.5 $\mu$M. When the inorganic phosphorus concentration in the medium was lowered from 25 to 10 $\mu$M, the levels of geosmin in the organism expressed as percentages per unit TOC and chlorophyII-$\alpha$ increased by 35% and 68%, respectively. When the initial pH of the medium was 9.4, geosmin content was 0.0824 $\mu$g/mg C, which was 2-fold higher than that at pH 7.9 Consequently, the level of geosmin in Phormidium was found to vary with growth phases of the culture, external inorganic phosphorus concentration and external pH, while the release of geosmin was not significantly affected by the factors.

• Microbiology and Biotechnology Letters
• /
• v.18 no.3
• /
• pp.273-279
• /
• 1990

For poly- $\beta$ -hydroxybutyrate (PHB) production, a pink-pigmented facultative methylotrophic bacterium (PPFM) P-10 was newly isolated from soils through methanol-enrichment culture. The optimal medium composition for cell growth was 1.0% (vlv) of methanol as carbon source and l.Og/l of ,TEX>$NH_4Cl$, equivalent to C/N ratio of 13.2 at pH 7.0 and $30^{\circ}C$. To investigate the optimal condition for YHB accumulation, two-stage culture technique was adopted; first stage for cell growth and second stage for accumulation of PHB providing unbalanced growth conditions. The optimal PHB accumulation was 1.0% (vIv) of methanol and 0.26gll of $NH_4Cl$, C/N of 50.8 at pH 6.0. To overcome methanol inhibition on cell growth, intermittent feeding fed-batch culture technique was employed, and the cell concentration as high as 14gll with 40% of PHB was achieved. The purified PHB was identified using IR and $1^H NMR$ as homopolymer of 8hydroxybutyric acid. The absorption spectrum of extracted pink colored microbial pigment was alsa investigated.

• Korean Journal of Microbiology
• /
• v.51 no.3
• /
• pp.288-299
• /
• 2015

Lactobacillus brevis BK11 obtained from Baikkimchi was selected to study the effects of culture medium, initial pH, atmosphere composition, incubation temperature and time, and prebiotics on growth and production of antimicrobial substances. Growth and antimicrobial substances production of L. brevis BK11 were significantly higher in MRS broth than in BHI or M17 broth. The production of cell mass, lactic acid, and bacteriocin by BK11 strain was at maximum in MRS broth adjusted to pH 6.0. Aerobic and microaerobic conditions were favored cell growth and antimicrobial substances production than anaerobic condition. Biomass and lactic acid production and antimicrobial substances activity of BK 11 were significantly better at 30 and $37^{\circ}C$ than at $25^{\circ}C$. Growth of the strain BK11 entered the stationary growth stage at 24 h after inoculation, and decreased after 36 h. Antimicrobial activities of cell-free culture supernatant and bacteriocin solution were highest when cultured in MRS broth with an initial pH 6.0 for 24-30 h at $37^{\circ}C$. In addition, the highest cell number and lactic acid and bacteriocin production were recorded in the presence of 1 and 2% (w/v) fructooligosaccharide (FOS), however, inulin and raffinose did not affect biological and physicochemical characteristics and antimicrobial activities of L. brevis BK11 cultures. According to these results, production of antimicrobial substances by L. brevis KB11 was closely associated with cell density. Under optimal conditions for antimicrobial substances production, L. brevis BK11 effectively inhibited the growth of Helicobacter pylori ATCC 43504.

• Journal of Life Science
• /
• v.16 no.4
• /
• pp.605-611
• /
• 2006

To investigate the possible use of probiont in fish farming industry, a bacterium with inhibitory effect against Vibrio anguillarum was isolated from gastrointestinal tract of the marine fish of yellow tail. It was identified to be Bacillus amyloliquefaciens H41 based on biochemical and physiological characterization. The optimal growth conditions of the isolated strain were 1% peptone, 1.5% yeast extract, 1% sucrose, 0.5% NaCl, 0.05% $MgSO_4{\cdot}7H_20$, pH 7.0-8.0, and 20 hr of incubation between $28-35^{\circ}C$ under aeration. The culture supernatant of the isolated strain showed inhibition activity against V. anguillarum. Inhibition activity was cleared by forming a clear zone by a paper-disk method. The maximal production of growth inhibition factor was induced by cultivation under 1% peptone, 1.5% yeast extract, 1% sucrose, 1% NaCl, 0.05% $MgSO_4{\cdot}7H_20$, pH 7.5 and at $35^{\circ}C$. The highest growth inhibition factor production was observed after 16-24 hr cultivation under aeration. The culture supernatant of the isolated strain showed inhibition activity whereas no inhibition activity was shown from the standard B. amyloliquefaciens KCTC 1724 strain. The growth inhibition affected only against V. anguillarum among other pathogenic Vibrios tested here.

• Applied Biological Chemistry
• /
• v.49 no.1
• /
• pp.1-6
• /
• 2006

This study was carried out to evaluate the growth characteristics of Lactobacillus acidophilus KCCM 32820 and Propionibacterium freudenreichii KCCM 31227 in MRS (De Man-Rogosa-Sharpe), RCM (Reinforced Clostridial Medium) and whey broth. Bacterial growth, increase rate of TTA (Total Titratible Acidity) and decline rate of pH in broth were the greatest in 9-21 hr after culturing Lactobacillus acidophilus KCCM 32820 in MRS. Those were the greatest in 24-60 hr after culturing Propionibacterium freudenreichii KCCM 31227 in RCM. However changes of pH and TTA of broth were the greatest in 18-54 hr after culturing Propionibacterium freudenreichii in RCM after culturing Lactobacillus acidophilus in MRS for 36 hr. Viable cells of Lactobacillus acidophilus KCCM 32820 and Propionibacterium freudenreichii KCCM 31227 revealed larger numbers in 12% whey broth than in 6% whey broth. These also showed larger numbers in pasteurized whey broth than in sterilized whey broth. Lactobacillus acidophilus KCCM 32820 and Propionibacterium freudenreichii KCCM 31227 grew best in pasteurized 12% whey broth.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.21 no.1
• /
• pp.81-87
• /
• 2019

The investigation of mycelial growth for artificial cultivation in T. albuminosus determined that within PDA, YM, MEA medium, both KNCAF 9001 and 9002 strains showed the highest mycelial growth in MEA media with 89, 81 mm, respectively, followed by YM, PDA in respected order. Furthermore, optimal mycelial growth of 89 and 77 mm in 9001 and 9002, respectively, at 25 ℃. Mycelial growth rapidly decreased at 30 ℃, but it was confirmed that it survived at 40 ℃. At pH 6, mycelial growth was fast with growth of 89 and 88 mm for both 9001 and 9002, respectively. In the case of 9001, the addition of with cotton seed hull(80%) and rice bran (20%) each other resulted in maximum productivity of 99 mm/10 days. The result differed in order of corn cob(97 mm), oak sawdust(96 mm) and poplar sawdust(93 mm). Ultimately, the result confirmed that addition of rice bran in comparison to bran resulted in higher yield. Even with identical medium component, 9002 showed the same tendency as 9001 but its growth was relatively slower than 9001. The effect of mycelial growth on the moisture content of the medium was best at 101. 94 mm/10 days when the moisture content of 9001 and 9002 was 65%. Mycelial growth rate tended to be slower when the moisture content was higher or lower than 65%.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.2
• /
• pp.238-245
• /
• 2009

Pure culture experiments were conducted to assess the bacteriostatic and bactericidal effects of phlorotannins (PT) isolated from Ascophyllum nodosum (brown seaweed) on Escherichia coli O157:H7. In Exp. 1, one non-O157:H7 strain (25922) and three strains of E. coli O157:H7 (3081, EDL933 and E318N) were cultured in M9 medium with PT included at 0 (control), 25, 50 or $100{\mu}g/ml$ (n = 3). Bacterial growth was monitored by $OD_{600}$ at 0, 4, 6, 12 and 24 h, and by dilution plating at 0, 4, 6 and 24 h. All strains were inhibited (p<0.001) by PT to varying degrees. At 50 or $100{\mu}g/ml$, PT prevented growth of all four strains. At $25{\mu}g\;PT/ml$, growth of 25922, 3081, E318N and EDL933 was inhibited for 6, 12 and 24 h, respectively, but 25922 and 3081 resumed growth by 12 and 24 h. Direct plating confirmed bactericidal effects of PT on all four strains at $100{\mu}g/ml$, and on EDL933 and E318N at $50{\mu}g/ml$. In Exp. 2, strains 25922 and 3081 were incubated with no tannins or with $50{\mu}g/ml$ of PT, purified condensed tannins (CT) from Quebracho (Schinopsis balansaei), or purified tannic acid from Rhus semialata (Anacardiaceae) as hydrolysable tannins (HT). Strain 3081 was unaffected by HT or CT, but was completely inhibited (p<0.001) by PT at 4, 6 and 24 h. Strain 25922 was unaffected by HT, slightly inhibited by CT, and almost eradicated by PT at 4 and 6 h. Transmission electron microscopy revealed tannin-mediated alterations to bacterial cell walls. Phlorotannins from A. nodosum exhibit growth-inhibiting and bactericidal effects in vitro against the strains of E. coli O157:H7 investigated. Anti-E. coli efficacy of A. nodosum PT is superior to that of terrestrial tannins purified from Quebracho and from Rhus semialata.