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Treatment of a Cinchona robusta How. cell suspension culture with a homogenate of Phytophthora cinnamomi resulted in cessation of growth and a rapid induction of the biosynthesis of anthraquinone-type phytoalexins. The strongest
induction of anthraquinone biosynthesis was obtained when the elicitor was added in the early growth phase of the growth cycle.
The accumulation of anthraquinones was accompanied by a tri-phasic response in the activity of isopentenyl diphosphate (IPP)
isomerase (EC 5.3.3.2): phase I was characterised by a rapid induction of activity, reaching a maximum at 12 h after elicitation.
During phase II, IPP isomerase rapidly decreased to levels below those found in untreated cells. At phase III, IPP isomerase
activity increased again, reaching a second maximum at about 72 h after elicitation. During phase I, the activity of farnesyl
diphosphate synthase (EC 2.5.1.10) was found to be suppressed. Extraction and assay conditions were optimised for IPP isomerase.
The presence of Mn2+ in the incubation buffer resulted in a marked increase in the activity of the enzymes obtained from cells in phase I. The
induction of IPP isomerase in combination with a concomitant inhibition of farnesyl diphosphate synthase might result in an
efficient channeling of C5-precursors into phytoalexin biosynthesis.
Received: 23 August 1996 / Accepted: 20 March 1997 相似文献
3.
R. Rojas J. Alba I. Magaña-Plaza F. Cruz A.C. Ramos-Valdivia 《Biotechnology letters》1999,21(10):907-911
Dioscorea deltoidea cell suspension cultures were established in modified Murashige and Skoog medium. The diosgenin production increased from 0.10 g–1 to 3.98 g–1 dry cell weight when cells were cultivated in the light and in a growth medium limited in phosphate and sucrose. The addition of 1.3 g of autoclaved fungal mycelium of Alternaria tenuis per litre of cell culture growing in the dark induced the production of 0.04 mg diosgenin g–1 dry cell weight. In both cases, the production of diosgenin was preceded by a transient induction of isopentenyl diphosphate isomerase activity. 相似文献
4.
David J. Mendoza-Aguayo Héctor M. Poggi-Varaldo Jaime García-Mena Ana C. Ramos-Valdivia Luis M. Salgado Mayra de la Torre-Martínez Teresa Ponce-Noyola 《Archives of microbiology》2014,196(1):25-33
The catalytic fraction of the Cellulomonas flavigena PN-120 oligomeric β-glucosidase (BGLA) was expressed both intra- and extracellularly in a recombinant diploid of Saccharomyces cerevisiae, under limited nutrient conditions. The recombinant enzyme (BGLA15) expressed in the supernatant of a rich medium showed 582 IU/L and 99.4 IU/g dry cell, with p-nitrophenyl-β-d-glucopyranoside as substrate. BGLA15 displayed activity against cello-oligosaccharides with 2–5 glucose monomers, demonstrating that the protein is not specific for cellobiose and that the oligomeric structure is not essential for β-d-1,4-bond hydrolysis. Native β-glucosidase is inhibited almost completely at 160 mM glucose, thus limiting cellobiose hydrolysis. At 200 mM glucose concentration, BGLA15 retained more than 50 % of its maximal activity, and even at 500 mM glucose concentration, more than 30 % of its activity was preserved. Due to these characteristics of BGLA15 activity, recombinant S. cerevisiae is able to utilize cellulosic materials (cello-oligosaccharides) to produce bioethanol. 相似文献
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San Miguel-Chávez R Soto-Hernández M Ramos-Valdivia AC Kite G Martínez-Vázquez M del Rosario García M M Terrazas S T 《Biotechnology letters》2003,25(13):1055-1059
The production of erythroidines and other alkaloids was studied in cotyledons, callus and cell suspension cultures of Erythrina americana Miller. The cell suspension cultures, grown in Murashige & Skoog medium with naphthaleneacetic acid (3 mg l–1) and kinetin (2 mg l–1), produced 89 and 17 g - and -erythroidines respectively per g dry wt. 相似文献
7.
Biosynthesis of sterols and triterpenes in cell suspension cultures of Uncaria tomentosa 总被引:2,自引:0,他引:2
Flores-Sánchez IJ Ortega-López J del Carmen Montes-Horcasitas M Ramos-Valdivia AC 《Plant & cell physiology》2002,43(12):1502-1509
Pectin administered to Uncaria tomentosa cell suspension cultures, was found to increase the production of triterpene acids (ursolic and oleanolic acid), however, neither growth nor sterol accumulation were affected. Cell cultures showed that pectin treatment caused a rapid threefold increase in the activities of enzymes involved in the biosynthesis of C(5) and C(30 )isoprenoid, such as isopentenyl diphosphate isomerase and squalene synthase. The activity of a farnesyl diphosphatase, which could divert the flux of farnesyl diphosphate to farnesol, was two times lower in elicited than in control cells. Elicited cells also transformed more rapidly a higher percentage of [5-(3)H]mevalonic acid into triterpene acids. Interestingly, addition of terbinafine, an inhibitor of squalene epoxidase, to elicited cell cultures inhibited sterol accumulation while triterpene production was not inhibited. These results suggest that in U. tomentosa cells, both the previously mentioned enzymes and those involved in squalene 2,3-oxide formation play an important regulatory role in the biosynthesis of sterols and triterpenes. 相似文献
8.
Luna-Palencia GR Cerda-García-Rojas CM Rodríguez-Monroy M Ramos-Valdivia AC 《Biotechnology progress》2005,21(1):198-204
Growth and alkaloid production in Uncaria tomentosa cell suspension cultures were studied in Murashige and Skoog medium supplemented with 10 microM 2,4-dichlorophenoxyacetic acid, 10 microM kinetin, and 58 mM sucrose for maintenance and with 10 microM indole-3-acetic acid, 10 microM kinetin, and 58 mM sucrose for production. A U. tomentosa pale Uth-3 cell line, cultured in the production medium, showed a reduced lag phase and a specific growth rate (mu) of 0.27 day(-1), while cells growing in the maintenance medium showed mu = 0.20 day(-1). U. tomentosa cells growing in the production medium produced monoterpenoid oxindole alkaloids (MOA) in amounts of 10.2 +/- 1.6 microg g(-1) dry weight (DW). The chemical profile of MOA produced by in vitro cell cultures was similar to that found in the plant. After 10 subcultures, maximum MOA production decreased to 2.0 +/- 0.7 microg g(-1) DW, while tryptamine alkaloids (TA) were produced with a maximum of 6.2 +/- 0.4 microg g(-1) DW. The increase of initial sucrose concentration up to 145 mM in the production medium enhanced the cell biomass by 3.2-fold (from 10.2 +/- 0.1 to 32.8 +/- 1.1 g DW L(-1)), reduced mu from 0.27 to 0.23 day(-1), and provoked a substantial accumulation of TA (23.1 +/- 4.7 microg g(-1) DW). A high sucrose concentration stimulated MOA production in the maintenance medium (2.7 +/- 0.5 microg g(-1) DW), even in the presence of 2,4-dichlorophenoxyacetic acid. 相似文献
9.
Rojas-Rejn Oscar A. Poggi-Varaldo Hctor M. Ramos-Valdivia Ana C. Martnez-Jimnez Alfredo Cristiani-Urbina Eliseo de la Torre Martnez Mayra Ponce-Noyola Teresa 《Journal of industrial microbiology & biotechnology》2011,38(1):257-264
Derepressed mutant PR-22 was obtained by N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) mutagenic treatment of Cellulomonas flavigena PN-120. This mutant improved its xylanolytic activity from 26.9 to 40 U mg−1 and cellulolytic activity from 1.9 to 4 U mg−1; this represented rates almost 2 and 1.5 times higher, respectively, compared to its parent strain growing in sugarcane bagasse.
Either glucose or cellobiose was added to cultures of C. flavigena PN-120 and mutant PR-22 induced with sugarcane bagasse in batch culture. The inhibitory effect of glucose on xylanase activity
was more noticeable for parent strain PN-120 than for mutant PR-22. When 20 mM glucose was added, the xylanolytic activity
decreased 41% compared to the culture grown without glucose in mutant PR-22, whereas in the PN-120 strain the xylanolytic
activity decreased by 49% at the same conditions compared to its own control. Addition of 10 and 15 mM of glucose did not
adversely affect CMCase activity in PR-22, but glucose at 20 mM inhibited the enzymatic activity by 28%. The CMCase activity
of the PN-120 strain was more sensitive to glucose than PR-22, with a reduction of CMCase activity in the range of 20–32%.
Cellobiose had a more significant effect on xylanase and CMCase activities than glucose did in the mutant PR-22 and parent
strain. Nevertheless, the activities under both conditions were always higher in the mutant PR-22 than in the PN-120 strain.
Enzymatic saccharification experiments showed that it is possible to accumulate up to 10 g l−1 of total soluble sugars from pretreated sugarcane bagasse with the concentrated enzymatic crude extract from mutant PR-22. 相似文献
10.
Barrera-Islas GA Ramos-Valdivia AC Salgado LM Ponce-Noyola T 《Current microbiology》2007,54(4):266-270
The mutant strain PN-120 of Cellulomonas flavigena produces a ss-glucosidase that is 10-fold more active than the corresponding enzyme isolated from the parental strain. These enzymes were partially purified through Q Sepharose and Bio-Gel filtration. A single protein band was detected on polyacrylamide-gel electrophoresis/zymogram using 4-methylumbelliferyl-beta-D-glucoside. On sodium dodecyl sulfate-PAGE, the enzyme displayed three protein bands, suggesting that in C. flavigena the enzyme is oligomeric with a molecular mass of 210 kDa. On purification, the specific activity of ss-glucosidase isolated from PN-120 was increased 16-fold and showed three times more affinity for cellobiose than the enzyme of the parental strain; nevertheless, the optimum pH and temperature were similar for both enzymes. The kinetic parameters suggested that the increase in the activity of the enzyme, from the mutant strain, was caused by a mutation that affects the catalytic site of the enzyme. The partial amino-acid sequence of the isolated enzyme confirmed that it is a beta-glucosidase because of its homology with other beta-glucosidases produced by cellulolytic bacteria and fungi. 相似文献