iTRAQ-based Comparative Proteomic Analysis Provides Insights Into Tobacco Callus Response to Carbon Nanoparticles

Background: Carbon nanomaterials (CNMs) have attracted a great deal of research interest for their potential application in plants. Some types of CNMs have exhibited the ability on regulating the growth of plants, which showed a promising future in agriculture. However, detailed mechanism of their application in plants is still not well characterized especially at the molecular level.Methods: The biomass variation of tobacco callus was investigated to exposure of carbon nanoparticles (CNPs). During the incubation period, proteomic profiling in tobacco callus was investigated by using the isobaric tags for relative and absolute quantitation labeling (iTRAQ) coupled with 2D-LC MS/MS. The function of differentially expressed proteins were achieved by using a gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analysis by InterproScan, and qRT-PCR was used to confirm the results of the proteomic data.Results: The results showed that the growth of tobacco callus was enhanced by CNPs, with the optimal concentration at 50 mg/L. The expression levels of 198 cellular proteins were significantly up- or down- regulated after CNPs treatment. These differentially expressed proteins were involved in mitochondria and calcium-mediated signaling. Conclusions: We demonstrated CNPs have the ability to enhance the growth of tobacco callus. The proteomic profile changes of tobacco callus provided a deeper understanding of the highly complex regulatory mechanisms in tobacco callus exposed to CNPs.

Molecular and cytotoxicity investigations of Phytolacca americana (l.) root, leaf, and berry extracts

<p><strong>Background:</strong> Pokeweed anti-viral protein (PAP) and lectin are two of the toxic components of pokeweed, <em>Phytolacca</em> <em>americana</em>, suspected of affecting free grazing livestock and small herbivorous animals.</p><p><strong>Objectives:</strong> This research aimed to investigate the antimicrobial activity of the pokeweed extracts against two bacterial strains, the gram negative <em>Escherichia</em> <em>coli</em> and the gram positive <em>Staphylococcus</em> <em>aureus</em>, to investigate the toxicity of the extracts to cells of tobacco, <em>Nicotiana</em> <em>tabacum</em>, callus, and to investigate the presence of selected toxic constituents present in pokeweed.</p><p><strong>Methodology:</strong> Pokeweed plants were identified and brought to the laboratory and separated into roots and leaves. The berries were collected later in the growing season. Aqueous extracts were obtained by homogenizing the plant parts separately in sterile water followed by centrifugation. The supernatants were filter-sterilized and used for bacterial and tobacco callus growth inhibition assays. Total cytoplasmic proteins were also obtained by homogenizing the plant parts separately in protein extraction buffer and centrifuging. The supernatants were investigated for the presence of various toxins suspected of being present in pokeweed, using western blot analyses.</p><p><strong>Results and Conclusions:</strong> Pokeweed constituents possess growth inhibitory effects to gram negative E. coli and to <em>N</em>. <em>tabacum</em> callus but not of the gram positive S. aureus, and that all three plant parts studied were rich in lectin and lectin-like constituents such as PL-A, PL-C, and PL-G. No PL-B was detected in any of the plant extracts.</p>

Cytokinin content in the potato plant cv. Bintje as affected by ratio of Cl- : SO4-- nutrition

Cytokinin activity in the potato plant (<i>Solarium tuberosum</i> L.), estimated by the tobacco callus assay method, depends upon the ratio of Cl^- : SO₄^-- given to the plant (expressed as ppm) and upon the plant 'part or organ. The order of rising cytokinin activity for nutrient solutions tested, independent of the plant part or organ analysed, was as follows: 212 Cl : 127 S< 372 Cl : 40 S<0 Cl : 225 S. Similary, the plant parts showed the following order of rising cytokinin activity: roots, stems < leaf blades < tubers < leaf petioles, leafy tops.

Phosphorus compounds in callus tissue of Nicotiana tabacum L. treated with morphactins IT 3233 and IT 3456

The morphactins under examination blocked the growth of tobacco callus tis-sues at as low concentrations as l mg/dm³ (IT 3456) and 10 mg/dm³ (IT 3233). The growth inhibition was accompanied by an increase in dry matter content. An increment in total P level induced by morphactins was the result of inorganic P accumulation. It could be supposed that the compounds tested influence the permeability of plasma membranes. No direct relationship his been found between the action of morphactins on growth and the level of phosphorus compounds in tissues. It seems that both the morphactins have a little different mode of action.

The effect of benzene and its Chlorella vulgaris metabolites on the growth of tobacco tissue

The influence of benzene, phenol and catechol on the tobacco callus tissue (<i>Nicotiana tabacum</i> L. cv. Wisconsin No. 38) cultivated <i>in vitro</i> was studied. Although inhibition of callus tissue growth in relation to the control was observed in all variants, the benzene-induced inhibition was the most significant. When catechol and phenol were added to the cultivation medium together, callus tissue growth was similar to that of the control. The addition of catechol to the medium containing phenol presumably reduces the toxic effect of phenol on the callus tissue examined. Callus tissue growing in the presence of phenol, benzene and cathechol became senescent more rapidly than in the control. Moreover microscopic examination revealed significant changes in the callus structure.