• ALGAE
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• v.28 no.2
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• pp.185-192
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• 2013

A new cold-adapted Arctic strain of Haematococcus pluvialis from Blomstrandhalv${\o}$ya Island (Svalbard) is described. This strain is predominantly always in non-motile palmelloid stage. Transmission electron microscopy showed the presence of very thick cell wall and abundant lipid vesicles in the palmelloids, including red and green cells. The external morphology of the non-motile palmelloid and motile bi-flagellated cells of our strain is similar to H. pluvialis; however it differs from H. pluvialis in physiology. Our strain is adapted to live and produce astaxanthin in the low temperature ($4-10^{\circ}C$), whilst the usual growth temperature for H. pluvialis is between $20-27^{\circ}C$. Phylogenetic analysis based on 18S rRNA gene data showed that our strain nested within the Haematococcus group, forming a sister relationship to H. lacustris and H. pluvialis, which are considered synonymous. Therefore, we identified our Arctic strain as H. pluvialis.

• Microbiology and Biotechnology Letters
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• v.50 no.1
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• pp.71-80
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• 2022

Lipases (triacylglycerol acylhydrolases [EC 3.1.1.3]) are water-soluble enzymes. They catalyze the hydrolysis of fats and oils. A cold-active lipase from marine Bacillus cereus HSS, isolated from the Mediterranean Sea, Alexandria, Egypt, was purified and characterized. The total purification depending on lipase activity was 438.9 fold purification recording 632 U/mg protein. The molecular weight of the purified lipase was estimated to be 65 kDa using sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The optimum substrate concentration, enzyme concentration, pH, and temperature were 1.5 mM, 100 µl, pH 6 and 10℃, respectively. The lipase was tolerant to NaCl concentrations ranging from 1.5 to 4.5%. The lipase was affected by the tested metal ions, and its activity was inhibited by 16% in the presence of 0.05 M SDS. The application of the cold-active lipase for the removal of an oil stain from a white cotton cloth showed that it is a promising biological agent for the treatment of oily wastes and other related applications. To the best of our knowledge, this is the first report of the purification and characterization of a lipase from marine B. cereus HSS isolated from the Mediterranean Sea.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1067-1076
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• 2016

The gene encoding lipase (Lip98) from Aeromicrobium sp. SCSIO 25071 was cloned and functionally expressed in Escherichia coli. Lip98 amino acid sequence shares the highest (49%) identity to Rhodococcus jostii RHA1 lipase and contains a novel motif (GHSEG), which is different from other clusters in the lipase superfamily. The recombinant lipase was purified to homogeneity with Ni-NTA affinity chromatography. Lip98 showed an apparent molecular mass of 30 kDa on SDS gel. The optimal temperature and pH value for enzymatic activity were recorded at 30℃ and 7.5, respectively. Lip98 exhibited high activity at low temperatures with 35% maximum activity at 0℃ and good stability at temperatures below 35℃. Its calculated activation energy was 4.12 kcal/mol at the low temperature range of 15-30℃. Its activity was slightly affected by some metal ions such as K⁺, Ca²⁺, and Na⁺. The activity of Lip98 was increased by various organic solvents such as DMSO, ethanol, acetone, and hexane with the concentration of 30% (v/v) and retained more than 30% residual activity in neat organic solvent. The unique characteristics of Lip98 imply that it is a promising candidate for industrial application as a nonaqueous biocatalyst and food additive.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.590-599
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• 2014

This study was conducted to compare the cold tolerance of seven ground cover species, Orostachys japonica, Sedum oryzifolium, S. kamtschaticum 'SG1', S. reflexum, S. rupestre 'Blue Spruce', S. spurium 'Green Mental', and S. takesimense, which have been used for green roof and wall systems in Korea. Plants were grown in 10-cm pots and 1 g of tissues at stem-end and crown of each species were kept under either light or dark condition, respectively. For cold tolerance tests, plants were initially left at $4^{\circ}C$ and linearly cooled to 0, -4, -8, -12, -16, and $-20^{\circ}C$ at $-2^{\circ}C{\cdot}h^{-1}$ rate. Low temperature injury and regrowth rates were visually evaluated and assessed by image analysis, respectively. The lethal temperature ($LT_{50}$) of plant species was determined using electrolyte leakage measurements. S. reflexum was the most cold tolerant, showing the most survival at $-16^{\circ}C$, whereas S. oryzifolium and S. takesimense showed low temperature injury at $-8^{\circ}C$. Similar results were found with electrolyte leakage measurements at the stem end. For each species, the crown (Mean $LT_{50}:\;-12.15^{\circ}C$) was more cold tolerant than the stem end (Mean $LT_{50}:\;-10.47^{\circ}C$). In conclusion, S. reflexum and S. rupestre 'Blue Spruce' are recommended for planting in the central region of Korea during late fall and early winter, as they were more cold tolerant and showed more vigorous regrowth than the other tested plant species.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.3
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• pp.171-176
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• 2006

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass(Lolium multiflorum Lam.) in Grassland and Forages Division, National Livestock Research Institute, RDA, Suwon from 1987 to 2005. New variety, Kowinner as a tetraploid variety was dark green in leaf color and growth habit in autumn and early spring was semi-prostrate and medium, respectively Kowinner as a medium or late-heading variety was 19th May in heading date. Flag leaf length of Kowinner was 29 cm that was the same as control variety, Hwasan 101. Length of longest stem and plant length of Kowinner were 70 cm and 97 cm that was longer 3 cm than those of Hwasan 101, respectively. Stem width of Kowinner was thicker than that of Hwasan 101. Expecially, Kowinner was very good in regrowth. Cold tolerance of Kowinner was slightly weaker than that of Hwasan 101 and slightly stronger than that of Florida 80. Dry matter(DM) yield(12,884 kg/ha) of Kowinner was 8% more than that of Hwasan 101. In vitro dry matter digestibility and total digestible nutrient(TDN) of Kowinner were 76.2 and 63.3% that was 1.6 and 0.4% lower than those of Hwasan 101, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.145-150
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• 2007

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass (Lolium multiflorum Lam.) in Grassland and Forage Crops Division, National Institute of Animal Science, RDA, Cheonan from 1999 to 2005. New variety, 'Kospeed' is a diploid variety with green in leaf color, and has semi-erect and erect growth habit in late autumn and early spring, respectively. 'Kospeed' was on 1 May in heading date as a early-maturing variety. Also 'Kospeed' was wider by 0.2mm in flag leaf width, longer by 1cm in flag leaf length and shorter by 1cm in plant length than those of 'Florida 80', respectively. Stem width of 'Kospeed' was similar to that of 'Florida 80' and 'Hwasan 101'. Cold tolerance of 'Kospeed' was better than that of 'Florida 80'. Dry matter (DM) yield (13,257kg/ha) of 'Kospeed' was similar to that of 'Florida 80'. In vitro dry matter digestibility (IVDMD) and total digestible nutrient (TDN) of 'Kospeed' were 73.2% and 65.3% which are 2.1% and 1.7% higher than those of 'Florida 80', respectively. Acid detergent fiber(ADF) and neutral detergent fiber (NDF) of 'Kospeed' were 29.1% and 53.1% which are 2.1% and 2.3% lower than those of 'Florida 80', respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.1
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• pp.9-14
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• 2006

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass (Lolium multiflorum Lam.) at the Grassland and Forage Crops Division, National Livestock Research Institute, RDA at Suwon, Korea, from 1999 to 2005. The new variety 'Kogreen' is a diploid variety with a green leaf color and had semi-erect habit in late autumn and erect growth habit in early spring. The heading date of 'Kogreen' was on May 4, and for 'Florida 80' was May 2, both are considered as early-heading variety. 'Kogreen' was wider by 0.7mm in flag leaf width, longer by 2 cm in flag leaf length and shorter by 1cm in plant length than the control variety, Florida 80. Stem width of 'Kogreen' was similar to that of 'Florida 80' and 'Hwasan 101'. cold tolerance of 'Kogreen' was better than that of 'Florida 80'. Dry matter(DM) yield (12,884kg/ha) of 'Kogreen' was 3% less than that of 'Florida 80'. in vitro dry matter digestibility was 74.7% and total digestible nutrient was 65.1%, which are 3.6% and 1.5% higher than those of 'Florida 80', respectively. Acid detergent fiber and neutral detergent fiber of 'Kogreen' were 30.1% and 54.1% which are 1.9% and 1.3% lower than those of 'Florida 80', respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.3
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• pp.177-184
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• 2008

This experiment was carried out to breed a cold-tolerant variety of Italian ryegrass (Lolium multiflorum Lam.) in Grassland and Forage Crops Division, National Institute of Animal Science, RDA, Suwon from 1999 to 2006. ew variety, Kowinmaster as a diploid variety was light-green in leaf color and had medium and semi-erect growth habit in late autumn and early spring, respectively. Kowinmaster was 13th May in heading date as a medium-maturing variety. Especially, Kowinmaster was similar to Florida 80 in flag leaf width, longer 3cm in flag leaf length and longer 6cm in plant length than those of control variety, Florida 80, respectively. Stem width of Kowinmaster was similar to that of Florida 80. Cold tolerance of Kowinmaster was better than that of Florida 80. Dry matter yield (9,521 kg/ha) of Kowinmaster was 2% more than that of Florida 80. Feed value of Kowinmaster was 12.1% in crude protein, 70.9% in In vitro dry matter digestibility and 32.9% in acid detergent fiber that were similar to those of Florida 80, respectively, but in neutral detergent fiber, Kowimaster was 56.0% that was 1% lower than that of Florida 80.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.4
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• pp.275-280
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• 2005

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass (Lolium multiflorum Lam.) in Grassland and Forage Crops Division, National Livestock Research Institute, RDA, Suwon from 1997 to 2002. Hwasan 104 as a tetraploid variety was dark green in leaf color and had semi-prostrate and medium growth habit in late autumn and early spring, respectively. Hwasan 104 was 19th May in heading date as a late-heading variety. Especially, Hwasan 104 was broader in flag leaf and longer 7 cm in plant length, and thicker in stem width than those of control variety, Hwasan 101. Cold tolerance of Hwasan 104 was better than that of Hwasan 101 registered as a cold-tolerant variety. Dry matter (DM) yield of Hwasan 104 was $5\%$ more than DM 9,348 kg/ha of Hwasan 101. In vitro dry matter digestibility and total digestible nutrient of Hwasan 104 were 74.3 and $63.1\%$ which are 3.3 and $1.5\%$ lower than those of Hwasan 101, respectively. Acid detergent fiber and neutral detergent fiber of Hwasan 104 were 32.6 and $55.8\%$ which are 1.9 and $2.4\%$ higher than those of Hwasan 101, respectively.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.561-567
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• 2011

Cold tolerance of the native Rhododendron species which are on the verge of extinction in Korean nature were compared with the introduced species and its mechanism were studied physiologically with the investigation of the leaf angle, leaf curling, and photosynthetic activity. The degree of cold tolerance measured with the leaf burning after winter season was higher in the native species, Rhododendron brachycarpum and Rhododendron brachycarpum var. roseum than all the introduced species. 'Nova Zembla', an introduced species, showed high sensitivity to the low temperature. Changes in leaf angle by the low temperature were bigger in 2 native species and 'Parker's Pink' than the other introduced species and small comparatively in 'Nova Zembla' and 'Cunningham's White' cultivar. Leaf curling also occurred strongly in 2 native species by the low temperature. While, it was comparatively little and mild in the other introduced species. Therefore these results suggested that the leaf movement such as leaf angle change and curling adapted to the low temperature is positively related to the cold tolerance of 2 native species. By the way, such relationship is not explainable in the cold-sensitive 'Parker's Pink' cultivar showing comparatively stronger leaf movement. Photosynthetic activity measured before the winter season was high in the cold-tolerant R. brachycarpum and its recovery after winter season was faster in the 2 native species and the introduced 'Cynosure' cultivar than the other introduced species. They were the lowest in the most cold-sensitive 'Nova Zembla'. This phenomena occurred similarly even in the stomatal conductivity, suggesting that the movement of water from the roots to the leaves is better and then the leaf burning after winter season become small in the cold-tolerant species. The recovery of photosynthetic activity and stomatal conductivity was comparatively slower in the cold-sensitive 'Parker's Pink'. From the above results, leaf behavior adapted to the low temperature during the winter season and water movement to the leaves are related collectively to the cold tolerance represented as the leaf burning in the Rhododendron species is suggested.