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2.
Sung Ho Son Sung Mee Choi Kum Boo Choi Yun Hee Lee Dea Sook Lee Myung Suk Choi Young Goo Park 《Biotechnology and Bioprocess Engineering》1999,4(2):112-118
Calli were induced from 300,000 embryos isolated from immature to mature stage of seeds collected on late September from 14
elite trees. When the embryos were cultured onto plastic Petri-dish containing 20 mL of modified B5 basal medium supplemented
with 3% (w/v) sucrose, 500 mg/L casein hydrolysate, 250 mg/L myo-inositol, 0.5% (w/v) polyvinyl polypyrrolidon (PVPP), 2×MS
vitamins, 0.5 mg/L gibberellic acid, and 10 mg/L 2,4-D after 2 weeks of culture, yellowish-white calli were immediately formed
on the surfaces of embryos, and subcultured for 4 weeks in same culture medium. Because most of calli maintained for more
than 3 months were revealed differences in their colors, surface texture, and growth rate, visual selection was made for first
round screening. When the size of visually selected calli larger than 19 mm in their diameter were inoculated, persistent
proliferation was observed. Among the plating methods tested for the selection of rapid growing cell lines at single cell
and/or small cell aggregate level, 2-layer spread plating revealed as the best for single cell cloning. To enhance cell growth
and maintain high rate of viability for long-term culture of yew cells in bioreactor, final cell volume less than 50% in SCV
seemed to be the best. Time course study revealed that 30% of inoculum density was suitable for fed batch culture. Among the
tested conditional media, the rate of 1∶2 (old medium: fresh medium) was recorded at the best for cell growth. 相似文献
3.
Summary Production of tryptophan by a temperature sensitive recombinant microorganism (Escherichia coli W3110 trpLDtrpR
ts
tna
– (pCRT185)) was investigated. In a single-stage continous culture, at an elevated temperature, 42°C (derepressed condition), tryptophan concentration increased in an early phase of the fermentation, and then gradually decreased with time. The reduction in the production rate was mostly due to the segregation of the plasmid and subsequent increase of plasmid-free cells. However, the plasmid could be maintained stable at 37°C, with repressed condition oftrp-operon, over 200 generations. A two-stage continuous culture system, i.e. cell growth was maintained in the first stage at 37°C and gene expression was induced in the second stage at 42°C, was therefore tested to improve the performance of the fermentation system. Operation of the two-stage system showed that the plasmid stability was significantly improved, and the specific rate of tryptophan production was maintained almost constant for more than 500 hours in the second stage. 相似文献
4.
Cascade control of Escherichia coli glutamine synthetase. Purification and properties of PII protein and nucleotide sequence of its structural gene 总被引:20,自引:0,他引:20
A procedure was developed to purify large quantities of PII protein from an Escherichia coli strain which contains a multicopy plasmid harboring the structural gene of PII (the glnB gene). Ultraviolet spectra of uridylylated and unuridylylated PII were obtained using the purified PII and empirical formulas to calculate the concentration of protein and the average number of uridylylated subunits per molecule were derived. A continuous fluorometric assay for the measurement of uridylylated PII (PIID) and adenylyltransferase (ATase) was also established. Rate measurements at various concentrations of PIID and at a fixed concentration of ATase showed that a tetrameric PIID molecule interacts with only one ATase molecule at a time. The complete nucleotide sequence of the glnB gene was determined and parts of the deduced amino acid sequence were confirmed by the results of amino acid sequence analysis of peptides. The PII subunit consists of 103 amino acids (Mr = 11,580). Two tyrosines reside at positions 46 and 51, where Tyr51 is the site of uridylylation. Nucleotide sequence analysis of the upstream region showed no obvious sites for the binding of RNA polymerase, indicating that the glnB gene is a part of an as yet unidentified operon. 相似文献
5.
Summary Protoplasts were isolated from leaf mesophyll of hybrid poplar (Populus nigra X P. maximowiczii) with a mean yield of 10.4 x 106 protoplasts per g fresh weight using 2.0% Cellulase Onozuka R-10, 0.8% Macerozyme R-10, 1.2% Hemicellulase, 2.0% Driselase, and 0.05% Pectolyase Y-23 with CPW salts solution containing 0.6 M mannitol, 0.002 M DTT, 3 mM MES at pH 5.6. A liquid plating method produced the highest frequency of dividing protoplasts (48.6%) using an MS medium without NH4NO3. The highest percent of colony formation was 22.8%, produced with fabric supported semi-solid (0.5% w/v) agar plating method using the same culture medium. Growing cell colonies and/or micro-calli were transferred to a fresh semisolid agar medium containing 0.44 M BAP and 9.0 M 2,4-D. Multiple shoots were produced from protoplast-derived callus after culture on MS medium containing 6.8 M zeatin. After root induction on half-strength MS medium that lacked growth regulators, shoots were transferred to pots containing artificial soil mix.Abbreviations CPW
Cell and Potoplast Wash solution
- LPM
Liquid Plating Method
- LDM
Liquid Drop Method
- HDM
Hanging Drop Method
- FSPM
Fabric supported Semi-solid agar Plating Method
- DTT
Dithiothreitol
- MES
2-(N-morpholino) ethane sulfonic acid
- BAP
6-benzylaminopurine
- 2,4-D
2,4-dichlorophenoxy acetic acid
- NAA
-naphthalene acetic acid
- MS
Murashige and Skoog (1962) 相似文献
6.
7.
We examined the applicability of radiotelemetry to studies of acorn dispersal byApodemus mice and compared its efficiency with the of this spool-and-line method. Installation of a transmitter (2.2 g) onto acorns
did not interfere with the transporting and feeding behavior of the mice. We were able to detect all transmitter-installed
acorns and follow the daily changes in the sites in which they were hoarded, while we missed 59% of the spool-tied acorns
due to mice breaking the threads. Mice carried transmitter-installed acorns farther than spool-tied ones. The radiotelemetry
method is superior to the spool-and-line method and useful for the study of hoarding behavior in rodents. 相似文献
8.
9.
Nguyen Dinh Luyen Le Mai Huong Nguyen Thi Thu Ha Nguyen Thanh Tra Le Thi Tu Anh Nguyen Van Tuyen Katalin Posta Ninh The Son Hai Pham-The 《化学与生物多样性》2023,20(2):e202200456
The current report describes the chemical investigation and biological activity of extracts produced by three fungal strains Fusarium oxysporum, Penicillium simplicissimum, and Fusarium proliferatum isolated from the roots of Piper nigrum L. growing in Vietnam. These fungi were namely determined by morphological and DNA analyses. GC/MS identification revealed that the EtOAc extracts of these fungi were associated with the presence of saturated and unsaturated fatty acids. These EtOAc extracts showed cytotoxicity towards cancer cell lines HepG2, inhibited various microbacterial organisms, especially fungus Aspergillus niger and yeast Candida albicans (the MIC values of 50–100 μg/mL). In α-glucosidase inhibitory assay, they induced the IC50 values of 1.00-2.53 μg/mL were better than positive control acarbose (169.80 μg/mL). The EtOAc extract of F. oxysporum also showed strong anti-inflammatory activity against NO production and PGE-2 level. Four major compounds linoleic acid (37.346 %), oleic acid (27.520 %), palmitic acid (25.547 %), and stearic acid (7.030 %) from the EtOAc extract of F. oxysporum were selective in molecular docking study, by which linoleic and oleic acids showed higher binding affinity towards α-glucosidase than palmitic and stearic acids. In subsequent docking assay with inducible nitric oxide synthase (iNOS), palmitic acid, oleic acid and linoleic acid could be moderate inhibitors. 相似文献
10.
This paper reports a restriction map of a fragment of DNA encoding kanamycin resistance cloned from plasmid DNA of Campylobacter jejuni ABA94 in the recombinant plasmid pRS9421-1. In transposition experiments, kanamycin-resistant R751::km9421 transconjugants appeared at frequencies of 10-7 per donor cell. These transconjugants harboured a plasmid 4 kb larger than the parental 49 kb plasmid R751. Restriction enzyme analysis and Southern blot hybridization of these transconjugants showed that the kanamycin resistant determinant had transposed from recombinant plasmid pRS9421-1 to plasmid R751.The authors are with the Department of Genetics and Cellular Biology, Faculty of Science, University of Malaya, 59100 Kuala Lumpur, Malaysia 相似文献