Studies on Green Synthesis of Copper Nanoparticles Using Punica granatum

Aim: The present study aimed at green synthesis of copper nanoparticles using various plant extracts as reducing and stabilizing agents. It would also study the antibacterial effect of the synthesized copper nanoparticles. Place and Duration of Study: Department of Microbiology, Bhavan’s Vivekananda college of Science, Humanities and Commerce, Hyderabad, India. The duration of the study is for six months between May 2017 to October 2017. Methodology: The aqueous solutions of different plant extracts were mixed with CuSO4 solution and incubated for green synthesis of stable copper nanoparticles. These were tested by UV-Visible spectroscopy and SEM analysis. Antibacterial tests of the biosynthesized nanoparticles were carried out on Gram-positive Bacteria Staphylococcus aureus by Agar well assay. Results: The aqueous solutions of different plant extracts yielded stable copper nanoparticles as indicated by the O.D values tested using UV-Visible spectroscopy. The best plant extract that yielded higher amount of copper nanoparticles was fruit rind extract of Punica granatum. The synthesized nanoparticles were found to be 56-59 nm, characterized by Scanning Electron Microscopy (SEM). The synthesized copper nanoparticles exhibited a strong antibacterial activity against Staphylococcus aureus. Conclusion: The copper nanoparticles can be green synthesized using fruit rind extract of Punica granatum and these can be used as efficient antimicrobial agents against Staphylococcus aureus and the study is significant currently as drug resistant infections of Staphylococcus aureus are gaining much prevalence and prominence.

Studies on cytochrome oxidase in carbon tetrachloride treated rats.

Cytochrome c oxidase was purified from control and CCl4 treated rats and its kinetic properties were studied. The activity of the enzyme was inhibited by 51% in CCl4 (4 g per kg body weight for 24 hr) treated rats. Studies on the kinetic properties showed that the K(m) of the enzyme increased by 60% while Vmax decreased by 44% in CCl4 treated rats compared to controls. The content of cytochrome aa3 was decreased by 34% while cytochrome b and c were not affected by CCl4 treatment. Phosphatidylcholine, phosphatidylethanolamine and cardiolipin were decreased significantly by 40%, 49% and 60% respectively in CCl4 treated rats. A decrease in the cytochrome aa3 content and a change in the lipid environment of the membrane are probably responsible for a decreased rate of electron transfer from cytochrome c to oxygen.

Effect of psychosine on mitochondrial function.

The effect of psychosine on the rate of respiration at different segments of the electron transport chain, respiratory control ratio and the efficiency of phosphorylation was studied. The transfer of electrons through site I, site II and site III was studied independently. The transfer through site I and site III was inhibited by psychosine, whereas the transfer through site II was not inhibited. Cardiolipin, which is essential for the electron transfer through site I and III, was implicated to be responsible for the inhibition of electron transfer by psychosine. Electron carriers of site II are not sensitive to cardiolipin, so psychosine could not inhibit the electron transfer through this site. The ADP/O ratio and respiratory control ratio were inhibited by psychosine showing that it has an uncoupler like effect. Mitochondria isolated from rat liver, kidney and brain behaved essentially the same way in their response to psychosine. Cytochrome c oxidase was significantly inhibited by psychosine and the degree of inhibition was almost same in mitochondria and sub mitochondrial particles. The preence of outer membrane in mitochondria did not make any difference with respect to the action of psychosine on electron transport chain. Psychosine interacts at site I and site III and a change in the lipid environment of the membrane is responsible for the mitochondrial dysfunctions induced by psychosine. This represents a possible mechanism for the destruction of cells in Gaucher's and Krabbe's disease.

Effect of administration of galactosamine hydrochloride on rat liver mitochondria.

The effect of galactosamine on liver mitochondrial functions was studied in vivo in rats at 12hr, 24hr and 36hr after the administration of the drug. State 3 respiration decreased significantly with both NAD+ linked and FAD linked substrates. Respiratory control ratio, an index of membrane integrity and P/O ratio which is a measure of phosphorylation efficiency decreased significantly. There was a significant decrease in the activities of NADH dehydrogenase, succinate dehydrogenase and cytochrome oxidase. A significant decrease was also seen on membrane potential, cytochrome aa3, cytochrome b, cytochrome c and on phospholipids of mitochondria. The observed mitochondrial dysfunctions were related to increased lipid peroxidation, which could cause loss of membrane integrity and a decreased rate of phosphorylation. It is proposed that increased lipid peroxidation was responsible for the inhibition on both oxidation and phosphorylation in mitochondria in galactosamine treated rats.

Assessment of clinical significance: the number needed to treat.

The practising ophthalmologist is frequently confronted with treatment options shown to be "statistically significantly better" than those currently in use. Unfortunately what is statistically significant may not necessarily be clinically significant enough for the practitioner to change from the currently preferred method of treatment. In this article we use common ophthalmic examples to introduce the "number needed to treat" (NNT), as a simple clinical approach for the practising ophthalmologist wishing to assess the clinical significance of treatment options.