BACKGROUND The investigation of plant-based therapeutic agents in medicinal plants has revealed their presence in the extracts and provides the vision to formulate novel techniques for drug therapy.Vitex negundo(V.neg...BACKGROUND The investigation of plant-based therapeutic agents in medicinal plants has revealed their presence in the extracts and provides the vision to formulate novel techniques for drug therapy.Vitex negundo(V.negundo),a perennial herb belonging to the Varbanaceae family,is extensively used in conventional medication.AIM To determine the existence of therapeutic components in leaf and callus extracts from wild V.negundo plants using gas chromatography-mass spectrometry(GCMS).METHODS In this study,we conducted GC-MS on wild plant leaf extracts and correlated the presence of constituents with those in callus extracts.Various growth regulators such as 6-benzylaminopurine(BAP),2,4-dichlorophenoxyacetic acid(2,4-D),α-naphthylacetic acid(NAA),and di-phenylurea(DPU)were added to plant leaves and in-vitro callus and grown on MS medium.RESULTS The results clearly indicated that the addition of BAP(2.0 mg/L),2,4-D(0.2 mg/mL),DPU(2.0 mg/L)and 2,4-D(0.2 mg/mL)in MS medium resulted in rapid callus development.The plant profile of Vitex extracts by GC-MS analysis showed that 24,10,and 14 bioactive constituents were detected in the methanolic extract of leaf,green callus and the methanolic extract of white loose callus,respectively.CONCLUSION Octadecadienoic acid,hexadecanoic acid and methyl ester were the major constituents in the leaf and callus methanolic extract.Octadecadienoic acid was the most common constituent in all samples.The maximum concentration of octadecadienoic acid in leaves,green callus and white loose callus was 21.93%,47.79%and 40.38%,respectively.These findings demonstrate that the concentration of octadecadienoic acid doubles in-vitro compared to in-vivo.In addition to octadecadienoic acid;butyric acid,benzene,1-methoxy-4-(1-propenyl),dospan,tridecanedialdehyde,methylcyclohexenylbutanol,chlorpyrifos,n-secondary terpene diester,anflunine and other important active compounds were also detected.All these components were only available in callus formed in-vitro.This study showed that the callus contained additional botanical characteristics compared with wild plants.Due to the presence of numerous bioactive compounds,the medical use of Vitex for various diseases has been accepted and the plant is considered an important source of therapeutics for research and development.展开更多
Under appropriate culture conditions,plant cells can regenerate new organs or even whole plants.De novo organ regeneration is an excellent biological system,which usually requires additional growth regulators,includin...Under appropriate culture conditions,plant cells can regenerate new organs or even whole plants.De novo organ regeneration is an excellent biological system,which usually requires additional growth regulators,including auxin and cytokinin.Nitrate is an essential nutrient element for plant vegetative and reproductive development.It has been reported that nitrate is involved in auxin biosynthesis and transport throughout the growth and development of plants.In this study,we demonstrated that the ectopic expression of the MdNLP7 transcription factor in Arabidopsis could regulate the regeneration of root explants.MdNLP7 mainly participated in the regulation of callus formation,starting with pericycle cell division,and mainly affected auxin distribution and accumulation in the regulation process.Moreover,MdNLP7 upregulated the expression of genes related to auxin biosynthesis and transport in the callus formation stage.The results demonstrated that MdNLP7 may play a role in the nitrate-modulated regeneration of root explants.Moreover,the results revealed that nitrate–auxin crosstalk is required for de novo callus initiation and clarified the mechanisms of organogenesis.展开更多
Background Gossypium hirsutum undergoes rapid clonal propagation to regenerate a mature plant through tissue culture.However,the correlation between cotton leaf regeneration,callus induction,and regeneration ability w...Background Gossypium hirsutum undergoes rapid clonal propagation to regenerate a mature plant through tissue culture.However,the correlation between cotton leaf regeneration,callus induction,and regeneration ability was still obscure.In this research,cotton leaf regeneration level for 21 accessions in the field(new leaves)was observed after the first harvest,and a comparison between field regeneration level and callus induction with its regeneration capacity(new shoots and roots)for the same 21 accessions was carried out.Agronomic traits,including plant height,leaf area,fresh leaf weight,dry leaf weight,the number of flowers and bolls,and biochemical(proline content)and physiological(chlorophyll and carotenoid content)traits during the flowering stage of 21 upland cotton accessions,were investigated.Result A significant correlation between physiological parameters and callus induction was discovered.Callus induction and regeneration capacity of roots and shoots for hypocotyl,cotyledons,and shoot tip tissues were used to validate field leaf regeneration level after the first harvest.CCRI 24 showed significant leaf regeneration in the field and callus induction capacity through callus induction and regeneration.Conclusion We found a substantial relationship between field regeneration capability and callus induction with its regeneration capacity for the hypocotyl,cotyledons,and shoot tip.The results showed that ZS061,Lumian 378,Jimian 863,and ZS065 have the highest moisture retention capacity,while CCRI 24,Liaoyang Duomaomian,and Beizhe Gongshemian have the lowest moisture retention capacity.CCRI 24 has the highest leaf regeneration capacity in the field,while Beizhe Gongshemian has the lowest leaf regeneration capacity.All our result provides a clue for checking the regeneration capacity through leaf regeneration level in the field.展开更多
Objective:To determine the anti-bacterial efficacy of chloroform,ethanol,ethyl acetate and water extracts of inter-nodal and leaves derived calli extracts from Mentha arvensis(M.arvensis) against Salmonella typhi(S.ty...Objective:To determine the anti-bacterial efficacy of chloroform,ethanol,ethyl acetate and water extracts of inter-nodal and leaves derived calli extracts from Mentha arvensis(M.arvensis) against Salmonella typhi(S.typhi),Streptococcus pyogenes(S.pyogenes),Proteus vulgaris(P. vulgaris) and Bacillus subtilis(B.subtilis).Methods:The inter-nodal and leaves segments of M.arvensis were cut into 0.5-0.7 cm in length and cultured on Murashige and Skoog solid medium supplemented with 3%sucrose,gelled with 0.7%agar and different concentration of 2,4-Dichlorophenoxyacetie acid(2,4-D) either alone or in combinations.The preliminary phytochemical screening was performed by Brindha et al method.Antibacterial efficacy was performed by disc diffusion method and incubated for 24 h at 37℃.Results:Maximum percentage of callus formation(inter-nodal segments 84.3±0.78;leaves segments 93.8±1.27) was obtained on Murashige and Skoog’s basal medium supplemented with 3%sucrose and 1.5 mg/L of 2,4-D.The ethanol extracts of leaves derived calli showed the maximum bio-efficacy than other solvents.The leaves and stem derived calli extracts on Proteus sp.showed that the plants can be used in the treatment of urinary tract infection associated with Proteus sp.Through the bacterial efficacy studies,it is confirmed that the in vitro raised calli tissue was more effective compared to in vivo tissue.Conclusions:The bio-efficacy study confirmed that the calli mediated tissues showed the maximum zone of inhibition.The present study paved a protocol to establish high potential cell lines by in vitro culture.展开更多
Somatic embryogenesis of Fraxinus mandshurica has the problems of low somatic embryo(SE) yield,unsynchronized SE development,and a high percentage of deformed SEs.We aimed to improve F.mandshurica SE production by syn...Somatic embryogenesis of Fraxinus mandshurica has the problems of low somatic embryo(SE) yield,unsynchronized SE development,and a high percentage of deformed SEs.We aimed to improve F.mandshurica SE production by synchronizing SE development,improving SE quality,and inducing root formation to obtain complete regenerated plants.Cotyledons of immature zygotic embryos of F.mandshurica were induced to form callus and then SEs.The SE induction percentage from explants differed among 32 mother trees,and the one with the highest SE induction percentage(29.8%) was used for further experiments.The highest callus induction percentage was94.2% on 1/2-strength Murashige and Skoog medium(MS1/2)supplemented with 0.15 mg·L^(-1) naphthalene acetic acid.The highest callus proliferation coefficient(240.5) was obtained on McCown's Woody Plant Medium containing 0.1 mg·L^(-1)6-benzyl adenine and 0.15 mg·L^(-1) 2,4-dichlorophenoxyacetic acid.The highest number of SEs(1020.5 g~(-1) fresh weight) was obtained on MS1/2 medium supplemented with1 mg·L^(-1) 6-benzyladenine.The highest number of cotyledon embryos(397/g fresh weight) was obtained by incubating materials on medium containing 1 mg·L^(-1) abscisic acid and then applying a drying treatment.The cotyledon embryos were milky white,uniformly sized(average length 4.7 mm),and 80% of them were normal.The SE rooting percentage on 1/2 MS medium containing 0.01 mg·L^(-1) NAA was 37.5%.Overall,the germination percentage of SEs was 26.4%,and complete regenerated plants were obtained after transplanting and acclimation.These results provide more possibilities for the preservation and breeding of F.mandshurica.展开更多
Objective:To study callus induction from different explants(internode,leaf,root)and in vitro plantlets propagation from medicinally important plant Achyranthes aspera L.Methods:Sterilized explants were prepared by uni...Objective:To study callus induction from different explants(internode,leaf,root)and in vitro plantlets propagation from medicinally important plant Achyranthes aspera L.Methods:Sterilized explants were prepared by uning 0.1%HgCl_2 and 0.5%Bavistin and callus was obtained when cultured onto Murashige Skoog's(MS)medium by using different concentrations and combination of 2,4-D.NAA.BAP,IAA,IBA with 3%sucrose and 0.8%agar.Induced callus was immediately transferred to MS medium containing at different concentrations of phytohormones for shootlets and rootlets induction respectively.Results:Sterilization treatment of 0.1%HgCl_2.for 2-3 min and Bavistin 0.5%for 10-12 min showed the highest percentage of asepsis and survival rate.Maximum induction of callus was obtained from a combination of 2.0 mg/L 2,4-D and 0.5 mg/L NAA from leaf.Highest shootlets number(4.83±0.l7)and length(3.8±0.16)cm were observed on full strength MS medium when fortified with BAP 4.0 mg/L and KIN 0.5 mg/L.Concerted efforts of BAP 10 mg/L and NAA 0.5 mg/L on full strength MS medium showed highest leaf number(6.77±0.94).In vitro raised shoots were allowed to root on different strengths of MS medium fortified with IAA and IBA at different concentrations.Experimentally,3.0 mg/L IBA was enabled to induce maximum rootlets number(10.0±9.82)on full strength MS medium.Afterwards,regenerated shoots with well developed roots were successfully subjected to hardening process and were acclimatized.The survived plantlets showed 66.67%survival frequency without any morphological abnormality.Conclusions:The results demonstrated that different explants were good source of callus induction,morphology analysis as well as indirect plantlets regeneration.展开更多
The induction and proliferation of embryogenic callus are key steps for large-scale propagation of somatic embryogenesis pathway and long-term preservation of coniferous germplasm.Callus can be induced from immature e...The induction and proliferation of embryogenic callus are key steps for large-scale propagation of somatic embryogenesis pathway and long-term preservation of coniferous germplasm.Callus can be induced from immature embryos of Korean pine(Pinus koraiensis Sieb.et Zucc.;Pinaceae)as explants,but there are problems,such as low proliferation efficiency,loss of embryogenicity,poor vigor;thus,best conditions for proliferation and culture of immature embryos of Korean pine are not yet clear.To solve the problems with somatic embryogenesis of Korean pine and determine the best culture conditions for callus induction and proliferation,we varied hormone concentration,subculture cycle of proliferation and other plant growth regulators combinations in media to induce callus formation by megagametophytes of three Korean pine families at different developmental stages,then analyzed the effects on embryogenic callus retention and cell proliferation using a quadratic regression orthogonal rotation design.The results showed that the family origin and collection date of explants significantly affected callus induction(induction rate reached 1.67%).Embryogenic maintenance and callus proliferation were best on DCR medium supplemented with 0.25 mg L^(−1)6-benzyl adenine,1 mg L^(−1)naphthaleneacetic acid,30 g L^(−1)sucrose,500 mg L^(−1),L-glutamine,500 mg L^(−1)casein hydrolysis and 6.5 g L^(−1)agar.In addition,the combination of 2,4-dichlorophenoxyacetic acid+6-benzyl adenine also had a better proliferative effect on callus.The effects of different combinations of growth regulators on callus proliferation efficiency were significantly different.Transfer to new medium every 13–15 days not only maintained robust callus vigor,but also yielded a larger proliferation coefficient.The techniques and conditions for embryogenic callus induction and proliferation of Korean determined here will serve as a foundation for establishing a large-scale system for somatic embryogenesis and propagation of Korean pine.展开更多
Plant natural products including alkaloids,polyphenols,terpenoids and flavonoids have been reported to exert anticancer activity by targeting various metabolic pathways.The biological pathways regulated by plant produ...Plant natural products including alkaloids,polyphenols,terpenoids and flavonoids have been reported to exert anticancer activity by targeting various metabolic pathways.The biological pathways regulated by plant products can serve as novel drug targets.Plant natural compounds or their derivatives used for cancer treatment and some novel plant-based compounds which are used in clinical trials were discussed.Callus suspension culture with secondary metabolites can provide a continuous source of plant pharmaceuticals without time and space limitations.Previous research has shown that rice callus suspension culture can kill>95%cancer cells with no significant effect on the growth of normal cells.The role of candidate genes and metabolites which are likely to be involved in the process and their potential to serve as anticancer and anti-inflammatory agents were discussed.Large scale production of plant callus suspension culture and its constituents can be achieved using elicitors which enhance specific secondary metabolites combined with bioprocess technology.展开更多
This study was conducted to determine effects of 2,4-dichlorophenoxy acetic acid(2,4-D) and light on growth of gerbera(Gerbera jamesonii cv. Daxueju) callus. Callus was induced from both petiole and leaf explants of g...This study was conducted to determine effects of 2,4-dichlorophenoxy acetic acid(2,4-D) and light on growth of gerbera(Gerbera jamesonii cv. Daxueju) callus. Callus was induced from both petiole and leaf explants of gerbera on Murashige and Skoog medium supplemented with 3% sucrose and various concentrations of 2,4-D and placed under light and dark. Callus induction percentage, callus size and callus fresh and dry weights were efficiently higher when using petiole as explant. MS medium supplemented with 1.5 mg/L 2,4-D showed the highest callus induction percentage of 96.70%. Callus induced under light had larger weight mass. It was indicated that 1.5 mg/L 2,4-D and light could promote growth of gerbera callus from petiole explant.展开更多
This research reports on an efficient shoot proliferation and callus regeneration system for bamboo.Young, semi-lignified branches with one lateral bud from Drepanostachyum luodianense(Yi et R. S. Wang) Keng f.were us...This research reports on an efficient shoot proliferation and callus regeneration system for bamboo.Young, semi-lignified branches with one lateral bud from Drepanostachyum luodianense(Yi et R. S. Wang) Keng f.were used as explants. Disinfection with 0.1% HgCl2 for 8 min was the optimum treatment and the best medium for bud initiation was Murashige and Skoog(MS) medium containing 3.0 mg L-16-benzyladenine(BA). Multiple shoots were induced from nodal shoot segments on MS medium containing 5.0 mg L-1 BA, 0.5 mg L-1 kinetin(Kin), and 1.0 mg L-1 naphthaleneacetic acid(NAA). The highest frequency of callus formation(65.6%) was on MS medium containing 4.0 mg L-12,4-dichlorophenoxyacetic acid(2, 4-D), 0.5 mg L-1 NAA, and 0.1 mg L-1 thidiazuron(TDZ). The optimum medium for callus proliferation was MS medium with 4 mg L-12,4-D, 0.5 mg L-1 TDZ and 0.5 mg L-1 NAA, and the optimum hormone combination was 4 mg L-1 BA ? 0.5 mg L-1 NAA for callus redifferentiation(up to 85.6%). A 100% rooting was achieved on MS medium supplemented with 2.0 mg L-1 NAA and 0.5 mg L-13-indole butyric acid(IBA). Rooted plantlets were acclimatized in a greenhouse in humus soil ? perlite(1:1) substrate. These micropropagated callus induction and regeneration systems for bamboo will be useful for genetic engineering and multiplication.展开更多
Objective: To induce callus from the medicinally valuable species, Barringtonia racemosa L.(B. racemosa) whereby the formation of callus is essential for micropropagation studies and in vitro plant secondary metabolit...Objective: To induce callus from the medicinally valuable species, Barringtonia racemosa L.(B. racemosa) whereby the formation of callus is essential for micropropagation studies and in vitro plant secondary metabolites production.Methods: The callus induction potential in B. racemosa was assessed from endosperm explant cultured on different culture media and plant hormonal treatments. Lloyd and Mc Cown's woody plant medium and Murashige and Skoog's medium were used in the study as culture media. On the other hand, various concentrations and combinations of2,4-dichlorophenoxyacetic acid(1.0–2.0 mg/L) and kinetin(0.5–2.5 mg/L) had been incorporated in the culture media to exert the effects of auxin and cytokinin on callus induction.Results: From the present study, it was found that the profuse [(1.681 ± 0.770) g fresh weight,(0.239 ± 0.239) g dry weight] and friable callus formation was optimally produced with desirable morphology and considerable percentage of callus induction(56.70%) in endosperm explants cultured on 1.0 mg/L 2,4-dichlorophenoxyacetic acid and 1.5 mg/L kinetin in Murashige and Skoog's medium.Conclusions: A reliable protocol for inducing callus formation of profuse and friable morphology in endosperm explant of B. racemosa had therefore been successfully established.展开更多
The influence of exogenic hormones (indole-3-acetic acid (IAA), abscisic acid (ABA) and kinetin) on defense reaction of wheat (Triticum aestivum L.) calli to the bunt agent Tilletia caries (D.C.) Tul. & C. Tul. wa...The influence of exogenic hormones (indole-3-acetic acid (IAA), abscisic acid (ABA) and kinetin) on defense reaction of wheat (Triticum aestivum L.) calli to the bunt agent Tilletia caries (D.C.) Tul. & C. Tul. was studied. ABA and kinetin induced the oxalate oxidase activity, increased the Н2О2 level, decreased germination of fungi teliospores and induced on calli the occurrence of dense sites non-infected by pathogen. On the contrary, IAA led to the decrease of oxalate oxidase activity, loosening of calli and increase germination of bunt agent teliospores and growth of fungi mycelium, besides stimulated rhizoids formation of wheat calli. Probably, the accumulation of Н2О2 in wheat calli under the influence of kinetin and ABA connected with activity of oxalate oxidase is one of the factors increasing defense reaction of wheat to bunt agent.展开更多
The wild type maize genotype, B73, is not amenable for callus production and an efficient protocol for B73 maize callus induction has never been reported up-to-date. Scientific efforts in producing B73 maize callus us...The wild type maize genotype, B73, is not amenable for callus production and an efficient protocol for B73 maize callus induction has never been reported up-to-date. Scientific efforts in producing B73 maize callus using all known callus inducible media have been unsatisfactory. Here we developed and described an efficient protocol for callus induction from B73 maize seedlings. The protocol is based on well known callus inducible media CM4C where we have sequentially subtracted some chemical compounds and added some new compounds mediating cell proliferations. This newly described protocol was able to induce callus production in a wide range of crop species including rice and soybean. We found that cell proliferation factors, NAA (auxin analog) and 2,4 D (auxin influx carrier) were not only very crucial but required for positive B73 maize callus induction. The absence of one or the other will lead to the failure of B73 maize callus production. The well known CM4C callus induction composition lacks NAA. Our findings will advance genetic studies of maize mutants generated from B73 genotype background.展开更多
This paper reports the first successful isolation of protoplasts from G racilariopsis bailiniae and their callus formation. The base solution type, concentration of isolating enzymes, concentration of sorbitol, incuba...This paper reports the first successful isolation of protoplasts from G racilariopsis bailiniae and their callus formation. The base solution type, concentration of isolating enzymes, concentration of sorbitol, incubation time, temperature and pH of the enzyme solution were tested to optimize the protoplast yield. The optimized isolation conditions were: 40% base solution 3(deionized water containing 25 mmol/L MESTris and 25 mmol/L CaCl 2 ·2 H 2 O) and 60% crude Marinomonas sp. YS-70 agarase solution, containing 2% w/v cellulase, 1% w/v macerozyme R-10 and 0.4 mol/L sorbitol, with incubation for 4 h at 28°C and pH 6.5. The highest yield of viable protoplasts, which was obtained in these conditions, was(1.75±0.25)×10 6 cells/g fresh weight. Cell wall regeneration of most protoplasts from G. bailiniae was complete within 60 h and the first division of cells happened after ≥3 days. Two division types were observed in the first division of protoplasts from G. bailiniae— asymmetric division and symmetric division. After the first division, the cells underwent a series of divisions to form callus cell masses.展开更多
This review on current biotechnological methods in forestry for in vitro tissue cultures to define the effect of stress conditions on trees,concentrates on somatic embryogenesis.Callus tissue,the key product of somati...This review on current biotechnological methods in forestry for in vitro tissue cultures to define the effect of stress conditions on trees,concentrates on somatic embryogenesis.Callus tissue,the key product of somatic embryogenesis,grows over a tree wound under ex vitro conditions.Callus tissue can be used in research in areas such as pathogenic susceptibility at the embryonic level,effect of heavy metals,influence of low temperatures(cryopreservation),production of secondary metabolites and transformation of plants.Callus of arborescent plants can be induced in vitro by fungal elicitors to produce secondary metabolites for pharmaceutical and cosmetic industries and are strongly repellant to herbivores and can thus act to protect forests.Analyses of dual cultures demonstrated that callus tissue exposed to a pathogenic fungus responds by synthesizing low-molecular-mass proteins belonging to an immune protein class.Cryopreservation of embryonic callus tissue also has broad applications,e.g.,for valuable plant genotypes in gene banks.Without strategies to protect forests against stressfactors,forest ecosystems will degrade to the detriment of all life,including humans.In vitro biotechnological research using callus tissue contributes to progress in forestry and the disciplines of ecology,physiology,phytopathology,culture and selection of plants.展开更多
For investigation on the characteristics of ethanol metabolism in tissues of different phant species, calluses from eight selected plant species were cultured on medium supplemented with ethanol in tightly sealed cult...For investigation on the characteristics of ethanol metabolism in tissues of different phant species, calluses from eight selected plant species were cultured on medium supplemented with ethanol in tightly sealed culture flasks. Chauges of the ethanol level were detected by gas chromatography. During the culture period, the calluses or tobacco, potato and petunia were able to catabolize exogenous ethanol, resulting in the prominent decline of the ethanol level in the medium. The calluses of melon and peanut were also able to ca- tabolize ethanol but with lower efficiency. the other three calluses of carrot, soybean and rice did not catabo- lize ethanol but instead produced small to large amount of ethanol,resulting in the increase of the ethanol level in the media. It was also found that changing the balance between auxin and cytokinin could influence only the ethanol metabolism efficiency but could not change the metabolism patterns on ethanol of the cul- tured calluses .It can be concluded that, ethanol metabolism pattern of calluese in cultures is an innate physi- ological characteristic of the respective plant species.展开更多
This work provides some evidences for the saponinproduction of Panax notoginseng callus by using biologi-cally active,wall-related oligosaccharins.In anappropriate concentration,three kinds of oligosaccharinsstimulate...This work provides some evidences for the saponinproduction of Panax notoginseng callus by using biologi-cally active,wall-related oligosaccharins.In anappropriate concentration,three kinds of oligosaccharinsstimulated saponin formation or callus growth.Theconcentration of DO,GO and CO for saponin productionof Panax notoginseng callus culture were 15ppm,15ppmaud 20ppm respectively by comparing saponin yield.Itwas very obvious for DO to increase saponin contentwhen the concentration was 10ppm,and for GO tostimulate callus growth when the concentration was20ppm.It would be a good way to produce saponin byusing oligosaccharins in large scale culture in thefuture.展开更多
The resveratrol-enriched transgenic rice line Iksan526(IS526),first developed by the Rural Development Administration of Korea using genetic engineering techniques,shows beneficial health effects in mitigating metabol...The resveratrol-enriched transgenic rice line Iksan526(IS526),first developed by the Rural Development Administration of Korea using genetic engineering techniques,shows beneficial health effects in mitigating metabolic syndrome and obesity.However,the effects of IS526 on the differentiation of chondrocytes and the underlying mechanism have not been investigated in detail.In this study,the effects and cellular regulatory mechanisms of IS526 on rabbit articular chondrocytes were examined.Following IS526 callus extract treatment,the expression levels of differentiation-related proteins were detected via western blotting,Alcian blue staining and immune-luorescence staining.IS526 decreased the type Ⅱ collagen and proteoglycan levels in dose-and time-dependent manners.We further analyzed the effects of IS526 on skeleton genesis in zebrafish larvae using Alcian blue staining,which showed a reduction in cartilage formation along with increased production of matrix metalloproteinase(MMP)-13.IS526 also increased the phosphorylation of ERK1/2 and p38 kinase but inhibited the phosphorylation of Akt.Pharmacological inhibition of MMP-13 blocked the IS526-induced decrease in type Ⅱ collagen levels.Inhibition of p38 kinase or PI-3K/Akt with SB203580 and LY294002 enhanced the suppression of type Ⅱ collagen,but the blockage of ERK-1/2 by PD98059 rescued IS526-induced dedifferentiation.These results suggested that IS526 regulates type Ⅱ collagen and MMP-13 expression via the ERK1/2 and PI-3K/Akt pathways in rabbit articular chondrocytes.展开更多
While being one of the world's most important crops,maize ( Zea mays L.) is still difficult to regenerate in tissue culture which severely limits its improvement by genetic engineering.Currently,immature zygotic e...While being one of the world's most important crops,maize ( Zea mays L.) is still difficult to regenerate in tissue culture which severely limits its improvement by genetic engineering.Currently,immature zygotic embryos provide the predominantly used material for regeneration and transformation.However,the procedures involved are often laborious,time-consuming and season-dependent.Here,we further improved an efficient tissue culture and plant regeneration system that uses maize leaf segments of young seedlings as an alternative explant source.Embryogenic calli were evaluated by morphology,proliferation and regeneration capacity.All these indicated that seedling-derived leaf materials have the potential to replace immature embryos for tissue culture and regeneration.展开更多
文摘BACKGROUND The investigation of plant-based therapeutic agents in medicinal plants has revealed their presence in the extracts and provides the vision to formulate novel techniques for drug therapy.Vitex negundo(V.negundo),a perennial herb belonging to the Varbanaceae family,is extensively used in conventional medication.AIM To determine the existence of therapeutic components in leaf and callus extracts from wild V.negundo plants using gas chromatography-mass spectrometry(GCMS).METHODS In this study,we conducted GC-MS on wild plant leaf extracts and correlated the presence of constituents with those in callus extracts.Various growth regulators such as 6-benzylaminopurine(BAP),2,4-dichlorophenoxyacetic acid(2,4-D),α-naphthylacetic acid(NAA),and di-phenylurea(DPU)were added to plant leaves and in-vitro callus and grown on MS medium.RESULTS The results clearly indicated that the addition of BAP(2.0 mg/L),2,4-D(0.2 mg/mL),DPU(2.0 mg/L)and 2,4-D(0.2 mg/mL)in MS medium resulted in rapid callus development.The plant profile of Vitex extracts by GC-MS analysis showed that 24,10,and 14 bioactive constituents were detected in the methanolic extract of leaf,green callus and the methanolic extract of white loose callus,respectively.CONCLUSION Octadecadienoic acid,hexadecanoic acid and methyl ester were the major constituents in the leaf and callus methanolic extract.Octadecadienoic acid was the most common constituent in all samples.The maximum concentration of octadecadienoic acid in leaves,green callus and white loose callus was 21.93%,47.79%and 40.38%,respectively.These findings demonstrate that the concentration of octadecadienoic acid doubles in-vitro compared to in-vivo.In addition to octadecadienoic acid;butyric acid,benzene,1-methoxy-4-(1-propenyl),dospan,tridecanedialdehyde,methylcyclohexenylbutanol,chlorpyrifos,n-secondary terpene diester,anflunine and other important active compounds were also detected.All these components were only available in callus formed in-vitro.This study showed that the callus contained additional botanical characteristics compared with wild plants.Due to the presence of numerous bioactive compounds,the medical use of Vitex for various diseases has been accepted and the plant is considered an important source of therapeutics for research and development.
基金the National Natural Science Foundation of China(31972378)the Shandong Province Key R&D Program+1 种基金China(2021CXGC010802)the China Agriculture Research System of MOF and MARA(CARS-27)。
文摘Under appropriate culture conditions,plant cells can regenerate new organs or even whole plants.De novo organ regeneration is an excellent biological system,which usually requires additional growth regulators,including auxin and cytokinin.Nitrate is an essential nutrient element for plant vegetative and reproductive development.It has been reported that nitrate is involved in auxin biosynthesis and transport throughout the growth and development of plants.In this study,we demonstrated that the ectopic expression of the MdNLP7 transcription factor in Arabidopsis could regulate the regeneration of root explants.MdNLP7 mainly participated in the regulation of callus formation,starting with pericycle cell division,and mainly affected auxin distribution and accumulation in the regulation process.Moreover,MdNLP7 upregulated the expression of genes related to auxin biosynthesis and transport in the callus formation stage.The results demonstrated that MdNLP7 may play a role in the nitrate-modulated regeneration of root explants.Moreover,the results revealed that nitrate–auxin crosstalk is required for de novo callus initiation and clarified the mechanisms of organogenesis.
基金supported by Ministry of Agriculture and Rural Affairs(19221957).
文摘Background Gossypium hirsutum undergoes rapid clonal propagation to regenerate a mature plant through tissue culture.However,the correlation between cotton leaf regeneration,callus induction,and regeneration ability was still obscure.In this research,cotton leaf regeneration level for 21 accessions in the field(new leaves)was observed after the first harvest,and a comparison between field regeneration level and callus induction with its regeneration capacity(new shoots and roots)for the same 21 accessions was carried out.Agronomic traits,including plant height,leaf area,fresh leaf weight,dry leaf weight,the number of flowers and bolls,and biochemical(proline content)and physiological(chlorophyll and carotenoid content)traits during the flowering stage of 21 upland cotton accessions,were investigated.Result A significant correlation between physiological parameters and callus induction was discovered.Callus induction and regeneration capacity of roots and shoots for hypocotyl,cotyledons,and shoot tip tissues were used to validate field leaf regeneration level after the first harvest.CCRI 24 showed significant leaf regeneration in the field and callus induction capacity through callus induction and regeneration.Conclusion We found a substantial relationship between field regeneration capability and callus induction with its regeneration capacity for the hypocotyl,cotyledons,and shoot tip.The results showed that ZS061,Lumian 378,Jimian 863,and ZS065 have the highest moisture retention capacity,while CCRI 24,Liaoyang Duomaomian,and Beizhe Gongshemian have the lowest moisture retention capacity.CCRI 24 has the highest leaf regeneration capacity in the field,while Beizhe Gongshemian has the lowest leaf regeneration capacity.All our result provides a clue for checking the regeneration capacity through leaf regeneration level in the field.
文摘Objective:To determine the anti-bacterial efficacy of chloroform,ethanol,ethyl acetate and water extracts of inter-nodal and leaves derived calli extracts from Mentha arvensis(M.arvensis) against Salmonella typhi(S.typhi),Streptococcus pyogenes(S.pyogenes),Proteus vulgaris(P. vulgaris) and Bacillus subtilis(B.subtilis).Methods:The inter-nodal and leaves segments of M.arvensis were cut into 0.5-0.7 cm in length and cultured on Murashige and Skoog solid medium supplemented with 3%sucrose,gelled with 0.7%agar and different concentration of 2,4-Dichlorophenoxyacetie acid(2,4-D) either alone or in combinations.The preliminary phytochemical screening was performed by Brindha et al method.Antibacterial efficacy was performed by disc diffusion method and incubated for 24 h at 37℃.Results:Maximum percentage of callus formation(inter-nodal segments 84.3±0.78;leaves segments 93.8±1.27) was obtained on Murashige and Skoog’s basal medium supplemented with 3%sucrose and 1.5 mg/L of 2,4-D.The ethanol extracts of leaves derived calli showed the maximum bio-efficacy than other solvents.The leaves and stem derived calli extracts on Proteus sp.showed that the plants can be used in the treatment of urinary tract infection associated with Proteus sp.Through the bacterial efficacy studies,it is confirmed that the in vitro raised calli tissue was more effective compared to in vivo tissue.Conclusions:The bio-efficacy study confirmed that the calli mediated tissues showed the maximum zone of inhibition.The present study paved a protocol to establish high potential cell lines by in vitro culture.
基金supported by the Fundamental Research Funds for the Central Universities of China(2572018BW02)the National Natural Science Foundation of China (31400535 and 31570596)+1 种基金the Innovation Project of State Key Laboratory of Tree Genetics and Breeding (2016C01)the National Key R&D Program of China (2017YFD0600600)。
文摘Somatic embryogenesis of Fraxinus mandshurica has the problems of low somatic embryo(SE) yield,unsynchronized SE development,and a high percentage of deformed SEs.We aimed to improve F.mandshurica SE production by synchronizing SE development,improving SE quality,and inducing root formation to obtain complete regenerated plants.Cotyledons of immature zygotic embryos of F.mandshurica were induced to form callus and then SEs.The SE induction percentage from explants differed among 32 mother trees,and the one with the highest SE induction percentage(29.8%) was used for further experiments.The highest callus induction percentage was94.2% on 1/2-strength Murashige and Skoog medium(MS1/2)supplemented with 0.15 mg·L^(-1) naphthalene acetic acid.The highest callus proliferation coefficient(240.5) was obtained on McCown's Woody Plant Medium containing 0.1 mg·L^(-1)6-benzyl adenine and 0.15 mg·L^(-1) 2,4-dichlorophenoxyacetic acid.The highest number of SEs(1020.5 g~(-1) fresh weight) was obtained on MS1/2 medium supplemented with1 mg·L^(-1) 6-benzyladenine.The highest number of cotyledon embryos(397/g fresh weight) was obtained by incubating materials on medium containing 1 mg·L^(-1) abscisic acid and then applying a drying treatment.The cotyledon embryos were milky white,uniformly sized(average length 4.7 mm),and 80% of them were normal.The SE rooting percentage on 1/2 MS medium containing 0.01 mg·L^(-1) NAA was 37.5%.Overall,the germination percentage of SEs was 26.4%,and complete regenerated plants were obtained after transplanting and acclimation.These results provide more possibilities for the preservation and breeding of F.mandshurica.
基金Supported by Islamic University.Kushtia-7003.Bangladesh(Grant No.IUBT-1108)
文摘Objective:To study callus induction from different explants(internode,leaf,root)and in vitro plantlets propagation from medicinally important plant Achyranthes aspera L.Methods:Sterilized explants were prepared by uning 0.1%HgCl_2 and 0.5%Bavistin and callus was obtained when cultured onto Murashige Skoog's(MS)medium by using different concentrations and combination of 2,4-D.NAA.BAP,IAA,IBA with 3%sucrose and 0.8%agar.Induced callus was immediately transferred to MS medium containing at different concentrations of phytohormones for shootlets and rootlets induction respectively.Results:Sterilization treatment of 0.1%HgCl_2.for 2-3 min and Bavistin 0.5%for 10-12 min showed the highest percentage of asepsis and survival rate.Maximum induction of callus was obtained from a combination of 2.0 mg/L 2,4-D and 0.5 mg/L NAA from leaf.Highest shootlets number(4.83±0.l7)and length(3.8±0.16)cm were observed on full strength MS medium when fortified with BAP 4.0 mg/L and KIN 0.5 mg/L.Concerted efforts of BAP 10 mg/L and NAA 0.5 mg/L on full strength MS medium showed highest leaf number(6.77±0.94).In vitro raised shoots were allowed to root on different strengths of MS medium fortified with IAA and IBA at different concentrations.Experimentally,3.0 mg/L IBA was enabled to induce maximum rootlets number(10.0±9.82)on full strength MS medium.Afterwards,regenerated shoots with well developed roots were successfully subjected to hardening process and were acclimatized.The survived plantlets showed 66.67%survival frequency without any morphological abnormality.Conclusions:The results demonstrated that different explants were good source of callus induction,morphology analysis as well as indirect plantlets regeneration.
基金supported by the National Key R&D Program of China(2017YFD0600600).
文摘The induction and proliferation of embryogenic callus are key steps for large-scale propagation of somatic embryogenesis pathway and long-term preservation of coniferous germplasm.Callus can be induced from immature embryos of Korean pine(Pinus koraiensis Sieb.et Zucc.;Pinaceae)as explants,but there are problems,such as low proliferation efficiency,loss of embryogenicity,poor vigor;thus,best conditions for proliferation and culture of immature embryos of Korean pine are not yet clear.To solve the problems with somatic embryogenesis of Korean pine and determine the best culture conditions for callus induction and proliferation,we varied hormone concentration,subculture cycle of proliferation and other plant growth regulators combinations in media to induce callus formation by megagametophytes of three Korean pine families at different developmental stages,then analyzed the effects on embryogenic callus retention and cell proliferation using a quadratic regression orthogonal rotation design.The results showed that the family origin and collection date of explants significantly affected callus induction(induction rate reached 1.67%).Embryogenic maintenance and callus proliferation were best on DCR medium supplemented with 0.25 mg L^(−1)6-benzyl adenine,1 mg L^(−1)naphthaleneacetic acid,30 g L^(−1)sucrose,500 mg L^(−1),L-glutamine,500 mg L^(−1)casein hydrolysis and 6.5 g L^(−1)agar.In addition,the combination of 2,4-dichlorophenoxyacetic acid+6-benzyl adenine also had a better proliferative effect on callus.The effects of different combinations of growth regulators on callus proliferation efficiency were significantly different.Transfer to new medium every 13–15 days not only maintained robust callus vigor,but also yielded a larger proliferation coefficient.The techniques and conditions for embryogenic callus induction and proliferation of Korean determined here will serve as a foundation for establishing a large-scale system for somatic embryogenesis and propagation of Korean pine.
文摘Plant natural products including alkaloids,polyphenols,terpenoids and flavonoids have been reported to exert anticancer activity by targeting various metabolic pathways.The biological pathways regulated by plant products can serve as novel drug targets.Plant natural compounds or their derivatives used for cancer treatment and some novel plant-based compounds which are used in clinical trials were discussed.Callus suspension culture with secondary metabolites can provide a continuous source of plant pharmaceuticals without time and space limitations.Previous research has shown that rice callus suspension culture can kill>95%cancer cells with no significant effect on the growth of normal cells.The role of candidate genes and metabolites which are likely to be involved in the process and their potential to serve as anticancer and anti-inflammatory agents were discussed.Large scale production of plant callus suspension culture and its constituents can be achieved using elicitors which enhance specific secondary metabolites combined with bioprocess technology.
基金Supported by Major Science and Technology Project of Fujian Province(2015NZ0002-1)
文摘This study was conducted to determine effects of 2,4-dichlorophenoxy acetic acid(2,4-D) and light on growth of gerbera(Gerbera jamesonii cv. Daxueju) callus. Callus was induced from both petiole and leaf explants of gerbera on Murashige and Skoog medium supplemented with 3% sucrose and various concentrations of 2,4-D and placed under light and dark. Callus induction percentage, callus size and callus fresh and dry weights were efficiently higher when using petiole as explant. MS medium supplemented with 1.5 mg/L 2,4-D showed the highest callus induction percentage of 96.70%. Callus induced under light had larger weight mass. It was indicated that 1.5 mg/L 2,4-D and light could promote growth of gerbera callus from petiole explant.
基金supported by the National Key Research and Development Program of China under Grant2016YFD0600901Jiangsu Province ‘‘SANXIN’’ Support Project under Grant LYSX [2016]04+1 种基金National Natural Science Foundation for Young Scholars of China under Grant 31000294Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘This research reports on an efficient shoot proliferation and callus regeneration system for bamboo.Young, semi-lignified branches with one lateral bud from Drepanostachyum luodianense(Yi et R. S. Wang) Keng f.were used as explants. Disinfection with 0.1% HgCl2 for 8 min was the optimum treatment and the best medium for bud initiation was Murashige and Skoog(MS) medium containing 3.0 mg L-16-benzyladenine(BA). Multiple shoots were induced from nodal shoot segments on MS medium containing 5.0 mg L-1 BA, 0.5 mg L-1 kinetin(Kin), and 1.0 mg L-1 naphthaleneacetic acid(NAA). The highest frequency of callus formation(65.6%) was on MS medium containing 4.0 mg L-12,4-dichlorophenoxyacetic acid(2, 4-D), 0.5 mg L-1 NAA, and 0.1 mg L-1 thidiazuron(TDZ). The optimum medium for callus proliferation was MS medium with 4 mg L-12,4-D, 0.5 mg L-1 TDZ and 0.5 mg L-1 NAA, and the optimum hormone combination was 4 mg L-1 BA ? 0.5 mg L-1 NAA for callus redifferentiation(up to 85.6%). A 100% rooting was achieved on MS medium supplemented with 2.0 mg L-1 NAA and 0.5 mg L-13-indole butyric acid(IBA). Rooted plantlets were acclimatized in a greenhouse in humus soil ? perlite(1:1) substrate. These micropropagated callus induction and regeneration systems for bamboo will be useful for genetic engineering and multiplication.
基金Supported by Ministry of Education under Higher Education Department through Fundamental Research Grant Scheme(FRGS)with the grant number of FRGS/1/2012/STW/N03/UITM/02/01
文摘Objective: To induce callus from the medicinally valuable species, Barringtonia racemosa L.(B. racemosa) whereby the formation of callus is essential for micropropagation studies and in vitro plant secondary metabolites production.Methods: The callus induction potential in B. racemosa was assessed from endosperm explant cultured on different culture media and plant hormonal treatments. Lloyd and Mc Cown's woody plant medium and Murashige and Skoog's medium were used in the study as culture media. On the other hand, various concentrations and combinations of2,4-dichlorophenoxyacetic acid(1.0–2.0 mg/L) and kinetin(0.5–2.5 mg/L) had been incorporated in the culture media to exert the effects of auxin and cytokinin on callus induction.Results: From the present study, it was found that the profuse [(1.681 ± 0.770) g fresh weight,(0.239 ± 0.239) g dry weight] and friable callus formation was optimally produced with desirable morphology and considerable percentage of callus induction(56.70%) in endosperm explants cultured on 1.0 mg/L 2,4-dichlorophenoxyacetic acid and 1.5 mg/L kinetin in Murashige and Skoog's medium.Conclusions: A reliable protocol for inducing callus formation of profuse and friable morphology in endosperm explant of B. racemosa had therefore been successfully established.
文摘The influence of exogenic hormones (indole-3-acetic acid (IAA), abscisic acid (ABA) and kinetin) on defense reaction of wheat (Triticum aestivum L.) calli to the bunt agent Tilletia caries (D.C.) Tul. & C. Tul. was studied. ABA and kinetin induced the oxalate oxidase activity, increased the Н2О2 level, decreased germination of fungi teliospores and induced on calli the occurrence of dense sites non-infected by pathogen. On the contrary, IAA led to the decrease of oxalate oxidase activity, loosening of calli and increase germination of bunt agent teliospores and growth of fungi mycelium, besides stimulated rhizoids formation of wheat calli. Probably, the accumulation of Н2О2 in wheat calli under the influence of kinetin and ABA connected with activity of oxalate oxidase is one of the factors increasing defense reaction of wheat to bunt agent.
文摘The wild type maize genotype, B73, is not amenable for callus production and an efficient protocol for B73 maize callus induction has never been reported up-to-date. Scientific efforts in producing B73 maize callus using all known callus inducible media have been unsatisfactory. Here we developed and described an efficient protocol for callus induction from B73 maize seedlings. The protocol is based on well known callus inducible media CM4C where we have sequentially subtracted some chemical compounds and added some new compounds mediating cell proliferations. This newly described protocol was able to induce callus production in a wide range of crop species including rice and soybean. We found that cell proliferation factors, NAA (auxin analog) and 2,4 D (auxin influx carrier) were not only very crucial but required for positive B73 maize callus induction. The absence of one or the other will lead to the failure of B73 maize callus production. The well known CM4C callus induction composition lacks NAA. Our findings will advance genetic studies of maize mutants generated from B73 genotype background.
基金Supported by the China Agriculture Research System(No.CARS-50)the Science and Technology Program of Guangdong Province of China(Nos.2016A020222023,2015B090903081)the Project of Guangdong Province Education Department(No.2017KCXTD014)
文摘This paper reports the first successful isolation of protoplasts from G racilariopsis bailiniae and their callus formation. The base solution type, concentration of isolating enzymes, concentration of sorbitol, incubation time, temperature and pH of the enzyme solution were tested to optimize the protoplast yield. The optimized isolation conditions were: 40% base solution 3(deionized water containing 25 mmol/L MESTris and 25 mmol/L CaCl 2 ·2 H 2 O) and 60% crude Marinomonas sp. YS-70 agarase solution, containing 2% w/v cellulase, 1% w/v macerozyme R-10 and 0.4 mol/L sorbitol, with incubation for 4 h at 28°C and pH 6.5. The highest yield of viable protoplasts, which was obtained in these conditions, was(1.75±0.25)×10 6 cells/g fresh weight. Cell wall regeneration of most protoplasts from G. bailiniae was complete within 60 h and the first division of cells happened after ≥3 days. Two division types were observed in the first division of protoplasts from G. bailiniae— asymmetric division and symmetric division. After the first division, the cells underwent a series of divisions to form callus cell masses.
基金supported by DS 3414 theme from the Polish Ministry of Education and Science
文摘This review on current biotechnological methods in forestry for in vitro tissue cultures to define the effect of stress conditions on trees,concentrates on somatic embryogenesis.Callus tissue,the key product of somatic embryogenesis,grows over a tree wound under ex vitro conditions.Callus tissue can be used in research in areas such as pathogenic susceptibility at the embryonic level,effect of heavy metals,influence of low temperatures(cryopreservation),production of secondary metabolites and transformation of plants.Callus of arborescent plants can be induced in vitro by fungal elicitors to produce secondary metabolites for pharmaceutical and cosmetic industries and are strongly repellant to herbivores and can thus act to protect forests.Analyses of dual cultures demonstrated that callus tissue exposed to a pathogenic fungus responds by synthesizing low-molecular-mass proteins belonging to an immune protein class.Cryopreservation of embryonic callus tissue also has broad applications,e.g.,for valuable plant genotypes in gene banks.Without strategies to protect forests against stressfactors,forest ecosystems will degrade to the detriment of all life,including humans.In vitro biotechnological research using callus tissue contributes to progress in forestry and the disciplines of ecology,physiology,phytopathology,culture and selection of plants.
基金Supported by the Natural Science Foundation of Guangdong Province(No.950406)
文摘For investigation on the characteristics of ethanol metabolism in tissues of different phant species, calluses from eight selected plant species were cultured on medium supplemented with ethanol in tightly sealed culture flasks. Chauges of the ethanol level were detected by gas chromatography. During the culture period, the calluses or tobacco, potato and petunia were able to catabolize exogenous ethanol, resulting in the prominent decline of the ethanol level in the medium. The calluses of melon and peanut were also able to ca- tabolize ethanol but with lower efficiency. the other three calluses of carrot, soybean and rice did not catabo- lize ethanol but instead produced small to large amount of ethanol,resulting in the increase of the ethanol level in the media. It was also found that changing the balance between auxin and cytokinin could influence only the ethanol metabolism efficiency but could not change the metabolism patterns on ethanol of the cul- tured calluses .It can be concluded that, ethanol metabolism pattern of calluese in cultures is an innate physi- ological characteristic of the respective plant species.
文摘This work provides some evidences for the saponinproduction of Panax notoginseng callus by using biologi-cally active,wall-related oligosaccharins.In anappropriate concentration,three kinds of oligosaccharinsstimulated saponin formation or callus growth.Theconcentration of DO,GO and CO for saponin productionof Panax notoginseng callus culture were 15ppm,15ppmaud 20ppm respectively by comparing saponin yield.Itwas very obvious for DO to increase saponin contentwhen the concentration was 10ppm,and for GO tostimulate callus growth when the concentration was20ppm.It would be a good way to produce saponin byusing oligosaccharins in large scale culture in thefuture.
基金This work was supported by the National Research Foundation of Korea funded by the Korean Government(Grant No.2017R1D1A3B03033401)the Center for Women in Science,Engineering and Technology Grant funded by the Ministry of Science and ICT under the Program for Returners into Research and Development.
文摘The resveratrol-enriched transgenic rice line Iksan526(IS526),first developed by the Rural Development Administration of Korea using genetic engineering techniques,shows beneficial health effects in mitigating metabolic syndrome and obesity.However,the effects of IS526 on the differentiation of chondrocytes and the underlying mechanism have not been investigated in detail.In this study,the effects and cellular regulatory mechanisms of IS526 on rabbit articular chondrocytes were examined.Following IS526 callus extract treatment,the expression levels of differentiation-related proteins were detected via western blotting,Alcian blue staining and immune-luorescence staining.IS526 decreased the type Ⅱ collagen and proteoglycan levels in dose-and time-dependent manners.We further analyzed the effects of IS526 on skeleton genesis in zebrafish larvae using Alcian blue staining,which showed a reduction in cartilage formation along with increased production of matrix metalloproteinase(MMP)-13.IS526 also increased the phosphorylation of ERK1/2 and p38 kinase but inhibited the phosphorylation of Akt.Pharmacological inhibition of MMP-13 blocked the IS526-induced decrease in type Ⅱ collagen levels.Inhibition of p38 kinase or PI-3K/Akt with SB203580 and LY294002 enhanced the suppression of type Ⅱ collagen,but the blockage of ERK-1/2 by PD98059 rescued IS526-induced dedifferentiation.These results suggested that IS526 regulates type Ⅱ collagen and MMP-13 expression via the ERK1/2 and PI-3K/Akt pathways in rabbit articular chondrocytes.
文摘While being one of the world's most important crops,maize ( Zea mays L.) is still difficult to regenerate in tissue culture which severely limits its improvement by genetic engineering.Currently,immature zygotic embryos provide the predominantly used material for regeneration and transformation.However,the procedures involved are often laborious,time-consuming and season-dependent.Here,we further improved an efficient tissue culture and plant regeneration system that uses maize leaf segments of young seedlings as an alternative explant source.Embryogenic calli were evaluated by morphology,proliferation and regeneration capacity.All these indicated that seedling-derived leaf materials have the potential to replace immature embryos for tissue culture and regeneration.
