Determination of zinc oxide nanoparticles toxicity in root growth in wheat (Triticum aestivum L.) seedlings

The effect of zinc oxide nanoparticles (ZnONPs) was studied in wheat (Triticum aestivum L.) seedlings under in vitro exposure conditions. To avoid precipitation of nanoparticles, the seedlings were grown in half strength semisolid Murashige and Skoog medium containing 0, 50, 100, 200, 400 and 500 mg L−1 of ZnONPs. Analysis of zinc (Zn) content showed significant increase in roots. In vivo detection using fluorescent probe Zynpyr-1 indicated accumulation of Zn in primary and lateral root tips. All concentrations of ZnONPs significantly reduced root growth. However, significant decrease in shoot growth was observed only after exposure to 400 and 500 mg L−1 of ZnONPs. The reactive oxygen species and lipid peroxidation levels significantly increased in roots. Significant increase in cell-wall bound peroxidase activity was observed after exposure to 500 mg L−1 of ZnONPs. Histochemical staining with phloroglucinol-HCl showed lignification of root cells upon exposure to 500 mg L−1 of ZnONPs. Treatment with propidium iodide indicated loss of cell viability in root tips of wheat seedlings. These results suggest that redox imbalances, lignification and cell death has resulted in reduction of root growth in wheat seedlings exposed to ZnONPs nanoparticles

In vitro regeneration from internodal explants of bitter melon (Momordica charantia L.) via indirect organogenesis

Organogenic callus induction and high frequency shoot regeneration were achieved from internodal explants of bitter melon. About 97.5% of internodal explants derived from 30 day old in vivo grown plants produced green, compact nodular organogenic callus in Murashige and Skoog (MS) plus Gamborg et al. (1968) (B5) medium containing 5.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.0 μM thidiazuron (TDZ) after two successive transfers at 11 days interval. Adventitious shoots were produced from organogenic callus when it was transferred to MS medium supplemented with 4.0 μM TDZ, 1.5 μM 2,4-D and 0.07 mM L-glutamine with shoot induction frequency of 96.5% and regeneration of adventitious shoots from callus (48 shoots per explant). Shoot proliferation occurred when callus with emerging shoots was transferred in the same medium at an interval of 15 days. The regenerated shoots were elongated on the same medium. The elongated shoots were rooted in MS medium supplemented with 3.0 μM indole 3-butyric acid (IBA). Rooted plants were acclimatized in green-house and subsequently established in soil with a survival rate of 95%. This protocol yielded an average of 48 shoots per internodal explant after 80 days of culture.Keywords: Adventitious shoots, growth regulators, hardening, organogenic callus, Momordica charanti

In vitro regeneration from internodal explants of bitter melon (Momordica charantia L.) via indirect organogenesis

Organogenic callus induction and high frequency shoot regeneration were achieved from internodal explants of bitter melon. About 97.5% of internodal explants derived from 30 day old in vivo grown plants produced green, compact nodular organogenic callus in Murashige and Skoog (MS) plus Gamborg et al. (1968) (B5) medium containing 5.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.0 μM thidiazuron (TDZ) after two successive transfers at 11 days interval. Adventitious shoots were produced from organogenic callus when it was transferred to MS medium supplemented with 4.0 μM TDZ, 1.5 μM 2,4-D and 0.07 mM L-glutamine with shoot induction frequency of 96.5% and regeneration of adventitious shoots from callus (48 shoots per explant). Shoot proliferation occurred when callus with emerging shoots was transferred in the same medium at an interval of 15 days. The regenerated shoots were elongated on the same medium. The elongated shoots were rooted in MS medium supplemented with 3.0 μM indole 3-butyric acid (IBA). Rooted plants were acclimatized in green-house and subsequently established in soil with a survival rate of 95%. This protocol yielded an average of 48 shoots per internodal explant after 80 days of culture.Keywords: Adventitious shoots, growth regulators, hardening, organogenic callus, Momordica charanti

Effect of silver nanoparticles on phenolic compounds production and biological activities in hairy root cultures of Cucumis anguria

The present study describes the elicitor effect of silver ion (Ag+) and biologically synthesized silver nanoparticles (AgNPs) to enhance the biomass accumulation and phenolic compound production as well as biological activities (antioxidant, antimicrobial and anticancer) in genetically transformed root (hairy root) cultures of Cucumis anguria. The biomass of hairy root cultures was significantly increased by AgNPs whereas decreased in Ag+ elicitation at 1 and 2 mg/L. AgNPs-elicited hairy roots produced a significantly higher amount of individual phenolic compounds (flavonols, hydroxycinnamic and hydroxybenzoic acids), total phenolic and flavonoid contents than Ag+-elicited hairy roots. Moreover, antioxidant, antimicrobial and anticancer activities were significantly higher following AgNPs-elicitation compared with that in Ag+-elicited hairy roots. We suggest that AgNPs could be an efficient elicitor in hairy root cultures to increase the phytochemical production

Karyotype and nucleic acid content in Zantedeschia aethiopica Spr. and Zantedeschia elliottiana Engl.

Analysis of karyotype, nucleic deoxyribonucleic acid (DNA) content and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were performed in Zantedeschia aethiopica and Zantedeschia elliottiana. Mitotic metaphase in both species showed 2n=32. The chromosomes of both species were quite similar with medium length ranging from 1.55 ± 0.04 to 3.85 ± 0.12 μM in Z. aethiopica and 2.15 ± 0.04 to 3.90 ± 0.12 μM in Z. elliottiana. However, some differences were found in morphology and centromeric position among the chromosomes. Identification of individual chromosomes was carried out using chromosomes length, and centromeric positions. The karyotype of Z. aethiopica was determined to be 2n = 32 = 14 m + 18 sm and of Z. elliottiana to be 2n = 32 = 10 m + 22 sm. The 2C nuclear DNA content was found to be 3.72 ± 0.10 picograms (equivalent to 3638.16 mega base pairs) for Z. aethiopica and 1144.26 ± 0.05 picograms (equivalent to 1144.26 mega base pairs) for Z. elliottiana. Leaf protein analysis showed 11 and 9 bands for Z. aethiopica and Z. elliottiana, respectively, among which some were species specific. These results may provide useful information regarding Zantedeschia for the study of taxonomic relationships, genetics and breeding.Keywords: Zantedeschia, karyotype, mitotic metaphase, chromosomes, flow cytometr

Changes of phenolic compounds in LebZIP2-overexpressing transgenic plants

484-491The bZIP gene is a transcription factor that plays various roles in relation to plant stress and hormone signaling. This gene is also involved in plant environmental stress and herbicide tolerance. We generated Nicotiana benthamiana transgenic plants with LebZIP2-encoding gene isolated from tomatoes using Agrobacterium-mediated transformation. Transgenic seeds harvested from these T0 transgenic plants were grown and examined for gene transfer and changes in phenolic compounds in the T1 generation. RT-PCR analysis using a primer specific to the LebZIP gene confirmed that the gene was transferred to the T1 generation. We analyzed the increase and decrease tendency for 30 phenolic compounds using the T1 generation-transgenic plants and investigated the mechanism between the specifically increased compound and LebZIP2 gene. Gallic acid, homogentisic acid, protocatechuic acid, myricetin, t-cinnamic acid, and b-resorcyclic acid were identified as the phenolic compounds that increased in T1 transgenic plants overexpressing the LebZIP gene. Among these, homogentisic acid at 246.75-1055.19 µg/g, was increased by 2-5 fold in the T1 transgenic plants compared to the control. Protocatechuic acid was found at 1640.54-2456.00 µg/g and was increased by 2-4 fold in T1 transgenic plants. t-Cinnamic acid was present in a small amount of 23.14 µg/g in the control, whereas it was 102.19-135.47 µg/g in T1 transgenic plants, showing an increase of 4-5 folds. These results indicated that homogentisic acid, protocatechuic acid, and t-cinnamic acid among the 30 phenolic compounds analyzed, were significantly increased in LebZIP2-overexpressing T1 transgenic plants, and support the evidence that the LebZIP2 gene is significantly involved in the increment of three phenolic compounds

Jasmonic and salicylic acids enhanced phytochemical production and biological activities in cell suspension cultures of spine gourd (Momordica dioica Roxb)

In vitro cell suspension culture was established for the production of commercially valuable phytochemicals in Momordica dioica. The influence of elicitors in jasmonic acid (JA) and salicylic acid (SA) increased their effect on phytochemical production and biomass accumulation in M. dioica. The results indicate that compared with non-elicited cultures, JA- and SA-elicited cell suspension cultures had significantly enhanced phenolic, flavonoid, and carotenoid production, as well as antioxidant, antimicrobial, and antiproliferative activities. Furthermore, elicited cultures produced 22 phenolic compounds, such as flavonols, hydroxycinnamic acids, and hydroxybenzoic acids. Greater biomass production, phytochemical accumulation, and biological activity occurred in JA- than in SA-elicited cell cultures. This study is the first to successfully establish M. dioica cell suspension cultures for the production of phenolic compounds and carotenoids, as well as for biomass accumulation

Anti-malarial activity of 6-(8'Z-pentadecenyl)-salicylic acid from Viola websteri in mice

<p>Abstract</p> <p>Background</p> <p>Petroleum ether extracts of <it>Viola websteri </it>Hemsl (Violaceae) were reported to have anti-plasmodial activity against <it>Plasmodium falciparum in vitro</it>, with this activity being largely attributable to 6-(8'Z-pentadecenyl)-salicylic acid (6-SA).</p> <p>Methods</p> <p>The schizontocidal activity of 6-SA on early <it>Plasmodium berghei </it>infections was evaluated in a four-day test. The possible 'repository' activity of 6-SA was assessed using the method described by Peters. The median lethal dose (LD₅₀) of 6-SA, when given intraperitoneally, was also determined using uninfected ICR mice and the method of Lorke.</p> <p>Results</p> <p>In the present study, 6-SA was found to have anti-malarial activity <it>in vivo</it>, when tested against <it>P. berghei </it>in mice. 6-SA at 5, 10 and 25 mg/kg·day exhibited a significant blood schizontocidal activity in four-day early infections, repository evaluations and established infections with a significant mean survival time comparable to that of the standard drug, chloroquine (5 mg/kg·day).</p> <p>Conclusion</p> <p>6-SA possesses a moderate anti-malarial activity that could be exploited for malaria therapy.</p

Direct shoot organogenesis from petiole and leaf discs of Withania somnifera (L.) Dunal

An efficient and reproducible procedure is described for direct shoot regeneration using petiole and leaf explants of Withania somnifera (L.). The shoots were mainly induced from the distal end of the petiole, whereas in leaf explants, shoot regeneration was initiated from the basal part and wounded tissue. The regeneration medium that induced the highest numbers of shoots in the petiole and leaf explants was Murashige and Skoog (MS) medium supplemented with 2 mg/l N6-benzyladenine (BA) alone or with 0.1 mg/l a-naphthalene acetic acid (NAA). The frequency of shoot regeneration was greatly influenced by the type of explant, the carbon source, the orientation of the explant, and the basal medium used in the regeneration medium. Explants produced shoot buds and adventitious shoots within four weeks. Histological analysis of the regenerating shoots showed that the shoot buds emerged from sub epidermal parenchymal cells, with no intermediate callus formation. Plantlets were rooted on MS alone or MS containing different concentrations of 3-indolebutyric acid (IBA). The addition of 1 mg/l IBA to the medium was most effective in inducing root formation. The regenerated plantlets were acclimatized in the greenhouse and successfully transferred to the field, with a 90% survival rate. The acclimatized plants showed normal flowering and were not morphologically different from the seed-derived mother plants.Key words: Histology, medicinal plant, plant growth regulator, plant regeneration, Withania somnifera