• Korean Journal of Food Science and Technology
• /
• v.46 no.6
• /
• pp.716-722
• /
• 2014

Aminopeptidase-active fractions from crude extract of the hepatopancreas of a common squid (Todarodes pacificus) were obtained using acetone (AC; 30-40%) and ammonium sulfate precipitation (AS; 60-70% saturation), anion exchange (AE-II; 0.2 M NaCl) and gel filtration chromatography (GF-I; 30-50 kDa), respectively. The debittering capacity of GF-I fraction based on the aminopeptidase activity (89.2 U/mg), recovery (56.6%) and sensory evaluation (1.0) was better than that of other fractions. Release of amino acids increased as incubation time was increased, and the bitterness of the enzyme reaction mixtures decreased. Incubation with the GF-I fraction for 24 h resulted in the hydrolysis of several peptides, as revealed by reverse-phase HPLC profiles. Peaks 3, 5 and 6 showed the decreased area (%), whereas peaks 1, 2 and 4 showed the increased area. The GF-I fractions were found to be suitable for reducing bitterness in protein hydrolysates by catalyzing the hydrolysis of bitter peptides.

• Journal of Animal Science and Technology
• /
• v.46 no.2
• /
• pp.243-250
• /
• 2004

In an effort to optimize tissue culture responses of Italian ryegrass(Lolium multiflorum Lam.) for future genetic manipulations to improve forage characteristics, the effects of culture medium supplements on tissue culture responses were investigated with mature seeds of three cultivars, 'Jeanne', 'Florida-80' and 'Metro', as explant tissues. For all explants, MS medium containing 5mg/L 2,4-D was optimal for embryogenic callus induction from mature seed and had a strong effect on successive plant regeneration. The optimal concentration of dicamba for the induction of embryogenic callus from mature seeds was 7mg/L. The highest plant regeneration frequency was observed when embryogenic callus was transferred to N6 medium supplemented with 1mg/L 2,4-D and 5mg/L BA. Plant regeneration frequency of callus cultured in the dark was higher than that of cultured in the light. Casein hydrolysate and L-proline improved both in embryogenic callus induction from mature seeds and plant regeneration. High-frequency regeneration system established in this study will be useful for molecular breeding of Italian ryegrass through genetic transformation.

• Korean Journal of Plant Tissue Culture
• /
• v.24 no.1
• /
• pp.49-52
• /
• 1997

The effects of several additives on plant regeneration were investigated from leaf disc culture of S. tuberosum cv. Atlantic which is known as poor in regeneration ability. The presence of 2 g/L casein hydrolysate significantly enhanced shoot regeneration. Addition of 10~20 $\mu$M $AgNO_3$, not only increased the frequency of shoot regeneration but also maintained the leaf disc green presumably by the inhibitory action of ethylene accumulation in vitro. Decrease of sucrose levels to below 3% significantly increased the degree of regeneration. The addition of CuSO$_4$had no effect on shoot regeneration.

• Plant Biotechnology Reports
• /
• v.4 no.2
• /
• pp.139-148
• /
• 2010

Jatropha curcas L. (Physic nut) is a commercially important non-edible oil seed crop known for its use as an alternate source of biodiesel. In order to investigate the morphogenic potential of immature embryo, explants from four developmental stages were cultured on medium supplemented with combinations of auxins and cytokinins. It was found that the size of embryo is critical for the establishment of callus. Immature embryos (1.1-1.5 cm) obtained from the fruits 6 weeks after pollination showed a good response of morphogenic callus induction (85.7%) and subsequent plant regeneration (70%) with the maximum number of plantlets (4.7/explant) on Murashige and Skoog's (MS) medium supplemented with IBA (0.5 $mg\;l^{-1}$) and BA (1.0 $mg\;l^{-1}$). The above medium when supplemented with growth adjuvants such as 100 $mg\;l^{-1}$ casein hydrolysate + 200 $mg\;l^{-1}$ L-glutamine + 8.0 $mg\;l^{-1}$ $CuSO_4$ resulted in an even higher frequency of callus induction (100%). Plant regeneration (90%) with the maximum number of plantlets (10/explant) was achieved on MS medium supplemented with 500 $mg\;l^{-1}$ polyvinyl pyrrolidone + 30 $mg\;l^{-1}$ citric acid + 1 $mg\;l^{-1}$ BA + 0.5 $mg\;l^{-1}$ Kn + 0.25 $mg\;l^{-1}$ IBA. It was observed that plantlet regeneration could occur either through organogenesis of morphogenic callus or via multiplication of pre-existing meristem in immature embryos. The age of immature embryos and addition of a combination of growth adjuvants to the culture medium appear to be critical for obtaining high regeneration rates. Well-developed shoots rooted on half-halfstrength MS medium supplemented with 0.5 $mg\;l^{-1}$ IBA and 342 $mg\;l^{-1}$ trehalose. The rooted plants after acclimatization were successfully transferred to the field in different agro-climatic zones in India. This protocol has been successfully evaluated on five elite lines of J. curcas.

• Korean Journal of Plant Tissue Culture
• /
• v.22 no.3
• /
• pp.143-148
• /
• 1995

The competence of callus formation and plant regeneration from root derived callus was higher in japonica cultivars than those of Tongil-type cultivars of rice. A japonica type cultivars Yeongdeogbyeo, showed the highest capacity (13%) for plant regeneration from root calli of 6 cultivars tested. The callus induced from seed and root tissues maintained higher capacity for plant regeneration during 7 passages of subculture on N$_{6}$ solid media at 2-week intervals. The maximum frequency (2 x 10$^{5}$ mL) of round cells and their cell colonies showed about 24 days after suspension culture of root-derived callus in N$_{6}$ medium with lmg/L 2,4-D, 300mg/L casein hydrolysate, 10mM L-proline, 20g/L sucrose and 30g/L sorbitol. The frequency of somatic embryo formation in suspension cultures of root-derived callus increased with prolonged advance of subculture time from 30 to 90 days, but their regenerative capacities decreased.

• The Korean Journal of Mycology
• /
• v.22 no.4
• /
• pp.332-337
• /
• 1994

Under standard condition (Han, et al., 1990: glucose 1%-nitrate 0.1% minimal medium, 30 ml in 9 cm plate, $10^6$ cells of inoculum per plate), wild type of Aspergillus nidulans developed both sexual and asexual organs in ballance, while velA1 mutant developed asexual ones preferentially. Increase of glucose concentration did not significantly affect the asexual sporulation. However, development of sexual organs were largely affected. It was greatly enhanced when favorable nitrogen source, for example, casein hydrolysate was added, which is contrary to the case of Neurospora or Saccharomyces where limitation of N source induces sexual development. On most of moderate C sources asexual development in $velA^+$ strain was largely inhibited except acetate on which only asexual spores were produced, while that in velA1 mutant strain was not affected. Lactose promoted the sexual development even in velA1 mutant indicating that lactose itself or its metabolic intermediate may induce sexual development independent of allelic state of velA gene. On other moderate favorable C sources, glycerol, galactose and ethanol, asexual development was largely inhibited in $velA^+$ strain but not in velA1 mutant strain. Sexual organs were, however, never produced on acetate. These results suggested that asexual development of wild type is largely dependent on C sources and the velA gene is involved in the repression of asexual development in not-enough-grown (non-competent) thalli resulting in preferential progression of sexual development.

• Asian Journal of Turfgrass Science
• /
• v.8 no.3
• /
• pp.137-147
• /
• 1994

We have established a high-frequency plant regeneration system via organogenesis from mature seed of Korean lawngrass(Zoysia japonica Steud.). The effects of 2,4-dichiorophenoxy acetic acid (2,4-D), 6-furfuryl amino purine (kinetin), $\alpha$-naphthaiene acetic acid (NAA), N6-benzyl amino pu-rine (BAP), and casein hydrolysate (CR) on cailus induction and multiple shoot formation on ex-posure to light were evaluated. Callus produced on the Murashige and Skoog (MS) medium containing 2,4-D and kinetin had high organogenesis potency. A single addition of 1.0 mg $L-^1$ 2,4-D significantly induced callus. Also, 1.0 mg L-$^1$ 2,4-D, with the addition of 0.1 mg $L-^1$ kinetin highly enlianced callus induction. The trend of cailus induction was also found on mediurn containing 0.1 mg $L-^1$ BAP with 1.0 mg $L-^1$2,4-D, and 1 g $L-^1$ CR with the addition of 1.0 mg $L-^1$ 2,4-D. However, NAA was no effective on callus formation. The growth of root was significantly high in the presence of 0.1 mg $L-^1$ kinetin compared to other concentrations. Over 2 mg $L-^1$ kinetin highly lengthened roots. Fresh weight of plantlet was highest on medium containing 0.1 mg $L-^1$ 2,4-D. Also, on medium containing 0.1 mg $L-^1$ BAP, fresh weight of piantlet was highly enhanced. BAP was significantly effective on multiple shoot formation, particularly when 2.0 mg $L-^1$ was added with 0.1 mg $L-^1$ 2,4-D. Callus induction and multiple shoot formation were achieved on MS basal medium containing 1.0 g $L-^1$ CH.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.2
• /
• pp.256-262
• /
• 2003

To enhance the production of heavy chain immunoglobulin G (HC IgG) in the suspension cultures of transgenic tobacco cells (Nicotiana tabacum), the effects of adding various cytokinins (i.e., growth regulators) and organic nitrogen sources to culture media were investigated. Four different cytokinins including kinetin, isopentenyladenine (IPA), 6-benzylaminepurine (BA), and zeatin were tested with or without dichlorophenoxyacetic acid (2,4-D), which is a typical growth regulator supplemented in the standard Murashige and Skoog (MS) medium. The productivity of intracellular HC IgG was increased by 36 and $42\%$, compared to the control, especially when IPA (2 mg/l) or BA (0.2 mg/l) was added to the media in the presence of 2,4-D, respectively. In the study of organic nitrogen sources, addition of each casein hydrolysate and tryptone to the culture media at a final concentration of 0.01 and 1 g/l, respectively. increased the productivity or he IgG as much as 68 and $67\%$, respectively, in comparison with the control, which was is MS medium without supplementation of any organic nitrogen sources. This study shows that the optimization of media composition could offer significant improvements in the production of foreign proteins in the suspension cultures of transgenic plants.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.2
• /
• pp.207-214
• /
• 2012

Laccase- and peroxidase-free tyrosinase has commercial importance in the production of L-3, 4-dihydroxyphenylalanine (L-DOPA), which is mainly used in the treatment of Parkinson's disease. In the present study, isolation of an actinomycetes microbial strain capable of producing only tyrosinase is reported. Among all soil isolates, three individual colonies revealed black color around the colony in the presence of tyrosine. Further screening for laccase and peroxidase activities using syringaldazine denoted that one of the isolates, designated as RSP-T1, is laccase and peroxidase negative and produces only tyrosinase. The microbe was authenticated as Streptomyces antibioticus based on 16S ribotyping. Effective growth of this isolate was noticed with the use of medium (pH 5.5) containing casein acid hydrolysate (10.0 g/l), $K_2HPO_4$ (5.0 g/l), $MgSO_4$ (0.25 g/l), L-tyrosine (1.0 g/l), and agar (15 g/l). The scanning electron micrograph depicted that the microbe is highly branched and filamentous in nature. The enzyme production was positively regulated in the presence of copper sulfate. The impact of different fermentation parameters on tyrosinase production depicted that the maximized enzyme titer values were observed when this isolate was grown at 6.5 pH and at $30^{\circ}C$ temperature under agitated conditions (220 rpm). Among all the studied physiological parameters, agitation played a significant role on tyrosinase production. Upon optimization of the parameters, the yield of tyrosinase was improved more than 100% compared with the initial yield.

• Journal of Microbiology
• /
• v.41 no.1
• /
• pp.34-40
• /
• 2003

Aspergillus nidulans, a homothalic ascomycete, has a complete sexual reproductive cycle as well as an asexual one. Both sexual and asexual development are known to be genetically programmed, but are also strongly affected by environmental factors including nutrients, light, temperature and osmolarity. We have examined these factors to define favored conditions for fruiting body (cleistothecium) formation. In general, fruiting body formation was enhanced where carbon and nitrogen sources were sufficient. Limitation of C-source caused predominant asexual development while inhibiting sexual development. When higher concentrations of glucose were supplied, more cleistothecia were formed. Other carbon sources including lactose, galactose and glycerol made the fungus develop cleistothecia very well, whereas acetate caused asexual sporulation only. Organic nitrogen sources like casein hydrolysate and glycine, and an increase in nitrate or ammonium concentration also enhanced sexual development. In addition to nutrient effects, low levels of aerobic respiration, caused either by platesealing or treatment with various chemicals, favored sexual development. Carbon limitation, light exposure and a high concentration of salts promoted asexual development preferentially, suggesting that stress conditions may drive the cell to develop asexual sporulation while comfortable and wellnourished growth conditions favored sexual development.