• Journal of Mushroom
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• v.6 no.1
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• pp.13-19
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• 2008

This experiment was carried out to examine physiological and cultural characteristics of two strains ASI 19003, 'Poplar field-cap mushroom' Agrocybe cylindracea, and ASI 19016, 'Chaxingo' A. chaxingu, at the bottle cultivation which have very similar morphological characteristics in genus Agrocybe. There was significant difference between the physiological and cultural characteristics of ASI19003 and ASI19016. The optimal temperature for the hyphal growth was $28^{\circ}C$ in the strain ASI19003 and $30^{\circ}C$ in ASI19016. The optimal pH was not different in two strains and these strains grew well at pH 5.5~7.0. But the optimal pH in the submerged culture was 5.5 in ASI19003 and 5.0 in ASI19016. Especially, hyphal growth of the strain ASI19016 was very poor at pH 6.0~7.3. The optimal carbon source for the growth was lactose in the strain ASI19003 and fructose in ASI19016, and nitrate sources were asparagine, alanine, and glycine in the strain ASI19003, and ammonium tartrate, asparagine, glycine, and alanine in ASI19016, respectively. The periods of incubation and fruiting body formation in the bottle cultivation during the spring were 27 and 13 days in the strain ASI19003, 29 and 17 days in ASI19016. The yields of fruit body were 114 g per bottle (850 $m{\ell}$ volume) in the strain ASI19003 and 100 g in ASI19016. In the summer, the periods of hyphal incubation and fruiting body formation were 29 and 11 days in the strain ASI19003, 30 and 12 days in ASI19016. The color of the cap in the ASI19003 strain according to temperature increase during the fruit body development become more pale, but the strain ASI19016 kept dark color relative to ASI19003. The fruiting body formation of the strain ASI19016 was faster than that of ASI19003. Accordingly, the cultivation of A. cylindracea ASI19003 during the spring, fall and winter, and A. chaxingu ASI19016 during the summer can keep high quality and stable supply all year round of these mushrooms.

• Microbiology and Biotechnology Letters
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• v.36 no.3
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• pp.215-220
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• 2008

Rahnella aquatilis AY2000 has an unique characteristic which produces an anti-yeast substance (AYS). The AYS of the strain AY2000 was always secreted on agar plate, however, its activity in liquid culture was labile upon storage of the medium. In this paper, cultural conditions of the strain AY2000 for the AYS production were investigated in liquid culture, and minimal inhibitory concentration (MIC) against Saccharomyces cerevisiae was determined for the AYS activity. MIC of the AYS cultured in PYG broth at $^25{\circ}C$ for 24 hr was $23.5{\mu}g/mL$, however, that in MYCS (pH 5.5) broth at the same condition was $15.5{\mu}g/mL$. The activity of the AYS had increased rather in MYCS broth excluded $NH_4$-citrate than in the same broth contained $NH_4$-citrate, and MIC of the AYS produced in MYCS broth without $NH_4$-citrate was $15.5{\mu}g/mL$. When the strain AY2000 was maintained in MYCS broth without $NH_4$-citrate but added $100{\mu}M$ $FeCl_3$, the activity of the AYS had increased and its MIC was $7.8{\mu}g/mL$. MIC of the AYS was $7.8{\mu}g/mL$ after the strain AY2000 was cultured in MYCS broth containing $100{\mu}M$ $FeCl_3$ without $NH_4$-citrate, however, its MIC was $31.3{\mu}g/mL$ after 48-60 hr culture in the same broth.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.79-88
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• 2004

Cordyceps pruinosa grows upon dead pupae of Lepidoptera and produces one or $3{\sim}4$ club-shaped stromata per host. The stromata have distinct club-shaped head and long stalk. The length of stromata varies from $1{\sim}3\;cm$. Apical head consists of densely crowded semi-immersed perithecia, which are $360{\sim}400\;{\times}\;180{\sim}200\;{\mu}m$ in size. Asci are $150\;{\mu}m$ in length and $2.8{\sim}3\;{\mu}m$ in diameter. Ascospores, which are $124{\sim}141\;{\mu}m$ in length, have thin thread-like structures in the middle with part-spores attached on both sides. Each ascospore does not separate into part-spores after dispersal, but each part-spore germinates and together develops a colony. The imperfect form produces phialides of $15{\sim}24\;{\times}\;2{\sim}3\;{\mu}m$ size, with spherical or spindle shaped conidia of $4{\sim}6\;{\times}\;1.8{\sim}2.4\;{\mu}m$ size, The anamorph was identified as Mariannaea elegans Samson. YMA and SDAY agar media with pH 7 was produced abundant mycelial growth with high density. Best mycelial growth was observed when dextrin was used as a carbon source. Lactose, saccharose and sucrose also produced high mycelial growth. Peptone, yeast extract and tryptone produced abundant mycelial growth, when used as nitrogen sources. Highest mycelial growth and density was observed when C/N ratio was 1 : 1 at the concentration of 12.5 g/l each. $KH_2PO_4$ was the best mineral source for mycelial growth. Highest mycelial dry wt. was produced in YM and SDAY broths. Optimum inoculum for 100 ml of liquid broth was 6 mycelial discs. Similarly, optimum liquid culture period was 7 days.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.1-6
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• 1974

1. The mycelial growth and sporulation of Mycogone perniciosa was compared on modified Czapek's media deficient in carbon source, nitrogen source, K,Mg, P or the heavy metal elements. The mycelial growth was significantly reduced in solution cultures lacking Mg, K or P and only a trace of growth occurred in solutions lacking carbon source or nitrogen source. Most sparse sporulation and smaller chlamydospores than on any of deficient agar media occurred on agar media dificient in carbon source or nitrogen source. 2. In both potato dextrose agar and malt extract solution, growth of the fungus was optimum at $25^{\circ}C$, and undetectable at $10^{\circ}C$ and $35^{\circ}C$. 3. Optimum pH for growth of this fungus was 7.0. 4. This fungus was killed in soil when exposed to $50^{\circ}C$ or higher for 20 minutes or more.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.906-914
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• 1994

Plastic behavior of two-phase intermetallic compounds based on $LI_{2}$-type $(Al, Cr)_3$ Ti was investigated using compression test at R.T. and 77K. $LI_{2}$ single phase alloys and two-phase alloys consisting of mainly $LI_{2}$ phase and a few or 20% second phases were selected from AI-Ti-Cr phase diagram. In general, compared with Llz single phase, two-phase alloys consisting of 20% second phase showed relatively high yield strength and poor ductility. Among the alloys, however, AI-21Ti-23Cr alloy consisting of 20% $Cr_{2}Al$ phase showed available ductility as well as high yield strength. Plastic behavior of $LI_{2}$ single phase alloys and two-phase alloys consisting of a few% $Cr_{2}Al$ was also investigated. Homogenization of arc melted ingots substantially reduced the amount of second phases but introduced extensive pore. When Cr content increased in $Ll_{2}$ single phase alloys after the homogenization, the volume fraction of pore in the alloys decreased, and no residual pore was observed in two-phase alloys consisting of a few% $Cr_{2}Al$ phase. Environmental effect on the ductility of the alloys was investigated using compression test at different strain rates($1.2 \times 10^{-4}/s$ and $1.2 \times 10^{-2}/s$). Environmental embrittlement was least significant in A1-25Ti-10Cr alloy consisting of LIZ single phase among the alloys tested in this study. However, based on the combined estimation of the pore formation, environmental embrittlement and ingot cast structure, AI-21Ti-23Cr alloy consisting of 20% $Cr_{2}Al$ as the second phase is expected to show the best tensile elongation behavior.

• Korean Journal of Food Science and Technology
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• v.48 no.3
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• pp.268-274
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• 2016

The purpose of this study was to investigate the immuno-stimulatory activity of the high-molecular-weight fraction (HMWF) of Cynanchum wilfordii (CW) extracts obtained by ultrafiltration in murine macrophage RAW 264.7 cells and to assess its immuno-stimulatory effect in mice. Ultrafiltration was performed with polyethersulfone membranes (30 kDa cutoff) in a cross-flow filtration system to obtain the HMWF of CW. The results showed that the HMWF increased the production of various cytokines such as tumor necrosis factor-${\alpha}$, interleukin-6, and nitric oxide in dose-ependent manners. In addition, HMWF treatment increased the relative spleen weight as well as splenocyte proliferation induced by concanavalin A or bacterial lipopolysaccharide in mice. Natural killer (NK) cell activity in the HMWF-treated group was significantly increased compared to that in the control group. These results suggest that the HMWF of CW can support the immune system through secretion of macrophage cytokines, thereby enhancing NK cell activity and murine splenocyte proliferation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.527-535
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• 2020

The purpose of this study was to establish a simple vitrification protocols to preserve animal cell lines derived from tissues of livestock that could be recultured. Bovine oviduct epithelial cells (BOEC) were used for the vitrification process using a 0.25 ml straw to increase cryopreservation efficiency. BOEC was cultured from the oviduct of 3.5-day estrus state, and the commercially available polyampholyte StemCell Keep^TM was used as a cryoprotective agent. Using different concentrations, the viability rates of BOEC in 5, 10, 25, 50, 75, and 100% in freezing media were investigated. Survivability was determined using a differential staining technique using a trypan blue test and a CYTO-13/PI staining protocol. The viability rates of BOEC in the trypan blue test were 5.6±11.8, 12.5±7.2, 53.0±2.7, 85.1±6.9, 79.8±0.6, and 60.7±6.7% with a respective concentration of StemCell Keep^TM. The viability rates in CYTO-13/PI staining were 4.6±2.5, 30.8±12.1, 58.4±2.5, 85.5±1.2, 79.8±0.6, and 71.2±1.2%, respectively. These results indicate that BOEC could be preserved with StemCell Keep^TM without toxicity in a 0.25-ml straw. The optimal concentration of vitrification solution with StemCell Keep^TM was determined to be 50% and can be considered as a proper preservation method for cryobanking.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.245-252
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• 2002

This study was to evaluate the in vitro survival of bovine enucleated MII (eMII) oocytes according to minimum volume cooling (MVC) freezing method and activation timing, and their in vitro development after somatic cell nuclear transfer (SONT). in vitro matured bovine oocytes for 20 h were stained with 5 $\mu\textrm{g}$/$m\ell$ Hoechst, and their 1st polar body and MII plate were removed by enucleation micropipette under UV filter. Also, eMII oocytes were subjected to activation after (group II) and before (group III) vitrification in 5 ${\mu}{\textrm}{m}$ ionomycin added CRlaa medium for 5 min. For vitrification, eMll oocytes were pretreated with EG10 for 5 min, exposed to EG30 for 30 sec and then directly plunged into L$N_2$. Thawing was taken by 4-step procedures at 37$^{\circ}C$. Survived eMII oocytes were subjected to SONT with cultured adult bovine ear cells. Reconstructed oocytes were cultured in 10 $\mu\textrm{g}$/$m\ell$ of cycloheximide and 2.5 $\mu\textrm{g}$/$m\ell$ of cytochalasin D added CRlaa medium for 1 h, and then in 10 $\mu\textrm{g}$/$m\ell$ of cycloheximide added CRlaa medium for 4 h. Subsequently, the reconstructed oocytes were incubated for 2 days and cleaved embryos were further cultured on cumulus-cell monolayer drop in CRlaa medium for 6 days. Survival rates of bovine vitrified-thawed eMII oocytes in group II (activation after vitrification and thawing) and III (activation before vitrification) were 81.0% and 84.9%, respectively. Fusion rates of cytoplasts and oocytes in group II and III were 69.0% and 70.0%, respectively, and their results were not different with non-frozen NT group (control, 75.2%). Although their cleaved rates (53.4% and 58.4%) were not different, cytoplasmic fragment rate in group II (32.8%) was significantly higher than that in group III (15.6%)(P<0.05). Also, subsequent development rate into >morula in group II (8.6%) was low than that in group III(15.6%). However, in vitro development rate in group III was not different with that in control (24.8%). This result suggested that MVC method was appropriate freezing method for the bovine eMII oocytes and vitrified eMII oocytes after pre-activation could support in vitro embryonic development after SONT as equally well as fresh oocytes.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.313-321
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• 1999

The purpose of these study was to investigate the use of a glass micropipette (GMP) as a vessel for vitrification of bovine IVP blastocysts, to compare the post-thaw survival rates of bovine blastocysts frozen in GMP with those frozen in OPS that have been previously investigated, and to improve the hatching rate following vitrification with GMP method. The GMP vessel permits higher freezing and warming rate than the OPS due to the higher heat conductivity of the glass and lower mass of the solution that contains the embryos. Groups of three bovine IVP blastocysts were sequentially placed into vitrification solution before being loaded into either the OPS or GMP vessels and immersed into L$N_2$within 20 to 25 sec. Post-thaw blastocysts were serially washed in 0.25 and 0.15 M sucrose in HM and TCM-199 for each 5 min, respectively, and then cultured in TCM 199 supplemented with 10% FCS for 24 h. The rate of blastocyst re-expanding did not significantly different for OPS (75.9%) and GMP (80.0%) methods (P＞0.05). The hatching rates in OPS (34.1%) and GMP (37.5%) methods were significantly lower than that in control group (54.3%) (P＞0.05). In addition, the rate of blastocyst re-expanding was significantly lower if blastocysts were vitrified in the wide portion of the micropipette rather than the narrow portion of the micropipette (83.3 vs 56.7%) (P＞0.05), even though three blastocysts were loaded per vessel. The hatching rate in 0.05% pronase solution treatment for 30, 60 and 90 see (45.9, 54.7 and 57.5%) were significantly higher than that in control (35.0%), even though there was not significantly different between 30 see and control. These results indicate that both vitrification vessels can provide high survival rates of bovine IVP blastocysts. However, the GMP vessel has the advantage over the OPS, in that the former does not need a cap to protect the vessel from floating after immersion in L$N_2$. The location of the embryos (narrow or wide portion of immersion) were considered to be limiting factors to the viability of bovine IVP embryos. The exposing in 0.05% pronase solution for 60 or 90 see can increase hatching rates of post-thaw bovine IVP blastocysts.

• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.483-488
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• 2007

Current feeder system (CFS) for Korea superconducting tokamak advanced research(KSTAR) project plays a role to interconnect magnet power supply (MPS) and superconducting (SC) magnets through the normal bus-bar at the room temperature(300 K) environment and the SC bus-line at the low temperature (4.5 K) environment. It is divided by two systems, i.e., toroidal field system which operates at 35 kA DC currents and poloidal field system wherein 20$\sim$26 kA pulsed currents are applied during 350 s transient time. Aside from the vacuum system of main cryostat, an independent vacuum system was constructed for the CFS in which a roughing system is consisted by a rotary and a mechanical booster pump and a high vacuum system is developed by four cryo-pumps with one dry pump as a backing pump. A self interlock and its control system, and a supervisory interlock and its control system are also established for the operational reliability as well. The entire CFS was completely tested including the reliability of local/supervisory control/interlock, helium gas leakage, vacuum pressure, and so on.