It has been suggested that electrical conductivity of a solution increases when the plant tissues are immersed in it. This is correct up to a limit above which the conductance becomes constant because, as the concentration [187] of leached salts, amino acids, potassium, phosphate, sugar, carbohydrates, etc. increases, the freedom of movement of these molecules and ions decreases. Aquaporins are water channels that not only selectively allow water molecules to flow in and out of the tissue but also reject certain substances in order to maintain the equilibrium. It is concluded that pre-soaking ALK inhibitor of seeds with very low concentration of oxidized MWCNT have positive effect on seed

germination. Exploitation of nanoparticles in different areas has become a fashionable trait even though their inadvertent use may create an imbalance in the ecosystem. For instance, Oberdörster [188] showed for the first time that the fullerenes, C60, cause lipid peroxidation in fish brain tissue, an example of adverse effect of nanoparticles in aquatic animals. Furthermore, fullerene

(C60) is known for its multifunctional use such as imaging probe, antioxidant and drug carrier [189], but it has been shown to exhibit genotoxicity and cytotoxicity and also to induce ROS in rat/fish cell lines [190–192]. C60 can selleck screening library cause damage to E. coli but not to the extent of being used as a drug. On the other hand, an attempt to exploit it in other areas without knowing its properties may be hazardous. Wang et al. [193] studied the effect of gold, silver, iron and C60 nanoparticles on the growth of E. coli, Bacillus subtilis and Agrobacterium tumefaciens. It was observed that silver nanoparticle

is most effective against all the above bacteria, while the other two nanoparticles have little or no influence on their growth. Perhaps, the silver nanoparticles easily penetrate the cell wall and interact with the pathogens inhibiting their further replication. The Au, Fe and C60 are regarded to be ineffective because they may be essential ingredients of these microbes. As little as 1 μg mL-1 silver nanoparticles Liothyronine Sodium are effective against the above bacterial strains. Approximately 5 μg mL-1 silver nanoparticles cause 100% mortality. It is clear from the SEM images that the cell wall of E. coli is damaged preventing further growth (Figure 10). In an experiment, Liu et al. [194] subjected human cell lines to silver nanoparticles of different sizes and demonstrated that smaller particles enter the cell more easily than the larger ones. Only penetration of nanoparticles into the cell wall is not the reason for their toxicity. It is concluded from a study that the toxicity of silver nanoparticles is due to their interaction with essential sulfhydryl group of the respiratory enzyme present in the bacterial cells [195]. Figure 10 Images of E. coli taken by SEM after exposure to nano-Ag. (A) Control and (B) 1 μg mL-1 nano-Ag. Magnifications and plotting scales are marked out in each picture [193].