Sulfated lentinan induced mitochondrial dysfunction leads to programmed cell death of tobacco BY-2 cells

Fabrication and optimization of chitosan-g-m-PEG-NH2 copolymer for advanced glioblastoma therapy using surface engineered lentinan loaded nanovesicles for nasal delivery

Glioblastoma multiforme (GBM) exhibits a high mortality with an incidence rate of 3-5 per 100,000 each year, which demands existence of newer approach for its treatment. The current study focuses on synthesis of novel lipidic nanovesicles (LNs) loaded with highly potent macromolecule Lentinan (LNT) and surface modified with methoxy poly (ethylene glycol; PEG) amine (m-PEG-NH2)-grafted-chitosan (CS) for intranasal delivery. The grafting procedure was optimized using Box Behnken design (BBD) to limit the use of organic solvents. The fabricated polymer showed enhanced aqueous solubility, biodegradability and mucoadhesion, resulting in higher nasal mucosa permeation (z = 53.52 μm). The presence of PEG enabled the sustained release of LNT till 48 h and assisted in achieving higher accumulation of LNT in CSF (41.7 ± 3.1 μg/mL) and a higher brain targeting potential of 96.3 ± 2.31 % (p < 0.05). In-vitro cellular studies showed the enhanced anti-GBM effect of LNT on U87 MG cells by reducing the cell viability (~2 times reduction in IC50 value) accompanied with large number of cells undergoing late apoptosis and death (p < 0.05) because of the higher cellular uptake (63.22 ± 3.01 ng/100 cells) of novel formulation. The copolymer comprising LNs were biocompatible, stable and can be used as an effective tool in the management of GBM.

The regulation of Cytochrome f by mannose treatment in broccoli and its relationship with programmed cell death in tobacco BY-2 cells

It is well established that programmed cell death (PCD) occurred in broccoli during postharvest senescence, but no studies have been conducted on the regulation of broccoli cytochrome f by mannose treatment and its relationship with PCD. In this study, we treated broccoli buds with mannose to investigate the changes in color, total chlorophyll content, gene expression related to chlorophyll metabolism, chloroplast structure, and cytochrome f determination during postharvest storage. In addition, to investigate the effect of cytochrome f on PCD, we extracted cytochrome f from broccoli and treated Nicotiana tabacum L. cv Bright Yellow 2 (BY-2) cells with extracted cytochrome f from broccoli at various concentrations. The results showed that cytochrome f can induce PCD in tobacco BY-2 cells, as evidenced by altered cell morphology, nuclear chromatin disintegration, DNA degradation, decreased cell viability, and increased caspase-3-like protease production. Taken together, our study indicated that mannose could effectively delay senescence of postharvest broccoli by inhibiting the expression of gene encoding cytochrome f which could induce PCD.

Cyanobacterial VOCs β-ionone and β-cyclocitral poisoning Lemna turionifera by triggering programmed cell death

β-Ionone and β-cyclocitral are two typical components in cyanobacterial volatiles, which can poison aquatic plants and even cause death. To reveal the toxic mechanisms of the two compounds on aquatic plants through programmed cell death (PCD), the photosynthetic capacities, caspase-3-like activity, DNA fragmentation and ladders, as well as expression of the genes associated with PCD in Lemna turionifera were investigated in exposure to β-ionone (0.2 mM) and β-cyclocitral (0.4 mM) at lethal concentration. With prolonging the treatment time, L. turionifera fronds gradually died, and photosynthetic capacities gradually reduced and even disappeared at the 96th h. This demonstrated that the death process might be a PCD rather than a necrosis, due to the gradual loss of physiological activities. When L. turionifera underwent the death, caspase-3-like was activated after 3 h, and reached to the strongest activity at the 24th h. TUNEL-positive nuclei were detected after 12 h, and appeared in large numbers at the 48th h. The DNA was cleaved by Ca2+-dependent endonucleases and showed obviously ladders. In addition, the expression of 5 genes (TSPO, ERN1, CTSB, CYC, and ATR) positively related with PCD initiation was up-regulated, while the expression of 2 genes (RRM2 and TUBA) negatively related with PCD initiation was down-regulated. Therefore, β-ionone and β-cyclocitral can poison L. turionifera by adjusting related gene expression to trigger PCD.

Melatonin Protects Tobacco Suspension Cells against Pb-Induced Mitochondrial Dysfunction

Recent studies have shown that melatonin is an important molecule in plant physiology. It seems that the most important is that melatonin effectively eliminates oxidative stress (direct and indirect antioxidant) and switches on different defence strategies (preventive and interventive actions) during environmental stresses. In the presented report, exogenous melatonin potential to protect Nicotiana tabacum L. line Bright Yellow 2 (BY-2) exposed to lead against death was examined. Analyses of cell proliferation and viability, the level of intracellular calcium, changes in mitochondrial membrane potential (ΔΨm) as well as possible translocation of cytochrome c from mitochondria to cytosol and subsequent caspase-like proteolytic activity were conducted. Our results indicate that pretreatment BY-2 with melatonin protected tobacco cells against mitochondrial dysfunction and caspase-like activation caused by lead. The findings suggest the possible role of this indoleamine in the molecular mechanism of mitochondria, safeguarding against potential collapse and cytochrome c release. Thus, it seems that applied melatonin acted as an effective factor, promoting survival and increasing plant tolerance to lead.

Cytotoxicity of the natural herbicidal chemical, berberine, on Nicotiana tabacum Bright yellow-2 cells

Berberine is a naturally occurring plant secondary metabolite with allelopathic and cytotoxic properties. We investigated the cytotoxic effects of berberine against tobacco Bright Yellow-2 (BY-2) cells. We found that berberine inhibited tobacco BY-2 cell growth in a concentration-dependent manner and the potency of berberine was comparable to the traditional herbicide glyphosate. Meanwhile, the in vivo test revealed that the herbicidal activity of berberine was also comparable to that of glyphosate. Further mechanism studies for the cytotoxicity demonstrated that berberine at concentrations of 40 μg/mL and 80 μg/mL induced cell death by causing mitochondrial membrane depolarization, irregular nuclei and chromatin condensation but not leading to significant apoptosis. Ultra-structure analysis through transmission electron microscopy (TEM) indicated that treatments with 40 μg/mL berberine for 2 d or 80 μg/mL berberine for 1 d induced cell damage, including nuclei morphological changes, cytoplasm and mitochondria degradation and cell wall fibrosis. Treatment at higher concentration of 80 μg/mL for longer period of 2 d, induced plasmolysis and severe damage to basic cell structure, which are indicative of explosive necrosis. Our results suggest that berberine was cytotoxic to tobacco BY-2 cells by inducing necrosis but not apoptosis. Cell wall, mitochondria, nuclei and chromatin were damaged and may be possible primary targets. Therefore, the herbicidal activity of berberine appears to be a complex process associated with multiple mechanisms of action.