American International Journal of Biology and Life Sciences en-US (Managing Editorial Board) (Editorial Assistant) Thu, 19 Mar 2020 00:00:00 +0600 OJS 60 Ecological Mechanism of Dinosaur Extinction <p>To analyze the reasons for the extinction of dinosaurs by applying the elimination methods, to exclude the factors that could not cause the worldwide extinction of the dinosaurs. At last obtain a conclusion that because the Ice Age had come on the Earth and caused the changing of climate that it had been becoming cold and arid from warmth and moist, and caused the <a href=";wd=&amp;eqid=ce59c5db00303363000000045e6bb98c">phyto-group</a> had been changing, which the Pteridophyte and gymnosperm groups fell off or died out, but the angiosperm groups had been developing and expanding. The characters of photosynthesis of producers of the biosphere had been becoming to the seasonal and regional from the perennial and global, the total of oxygen had reduced sharply in the atmosphere, the density of oxygen had declined, and finally affected the breath of dinosaurs, and led to the extinction of dinosaurs. And as the main producers of biosphere, the pteridophyte and gymnosperm groups had fallen off or died out were the mainly reasons for the creature’s extinction at the later of the Cretaceous period.</p> Huai Tang Gu ##submission.copyrightStatement## Thu, 19 Mar 2020 15:34:23 +0600 Antioxidant Potential of Morinda Lucida and Psidium Guajava Extracts and Actions Against Paracetamol- Induced Kidney and Liver Injuries in Rats <p>Antioxidant agents of plants origin have continued to attract interest because of the potential they hold in the maintenance of human health accompany with their minimal side effects. The present study sought to evaluate the comparative free radical scavenging activities of ethanol extracts of air dried <em>Morinda lucida</em> leaves (EMLL) and <em>Psidium guajava</em> leaves (EPGL) by measuring their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, nitric oxide (NOˉ) radical, 2,2 azinobis-( 3-ethylbenzothiazoline-6-sulfonic acid) (ABTS*), and inhibit lipid peroxidation (LPO). Antioxidant activities of the extracts were also determined in the plasma of the rats fed with the extracts by assaying for antiradical activity against DPPH and NO radicals <em>in vitro</em>. <em>In vivo</em> antioxidant effects of the extracts were also evaluated in paracetamol treated rats. Twenty rats were randomly divided into four groups for this study. Group 1 received normal feed as control, group 2 received 14.30mg/kg b.w of paracetamol by gavage, groups 3 and 4 received 400mg/kg b.w of EMLL and EPGL each for 7 days plus paracetamol on the 8<sup>th</sup> day respectively. Catalase (CAT) and superoxide dismutase (SOD) activities and malondialdehyde (MDA) status were assayed for in the kidney, liver and serum. Histopathological examinations of liver and kidney were also carried out. The results showed that EMLL and EPGL exhibited free radical scavenging ability in dose dependent manner towards DPPH, NO, ABTS radicals as well as inhibition of LPO. The results of evaluation of the antioxidant potentials of the extracts while in the plasma showed that they were associated with free radical scavenging activity <em>in vivo</em>. Paracetamol treatment caused significant (p&lt;0.05) decreases in SOD and CAT activities, and marked increase (p&lt;0.05) in MDA levels when compared with the control. However, compared with paracetamol only group, the extracts caused significant (p&lt;0.05) increase in SOD and CAT activities and decreased MDA levels. Histopathological analysis of kidney and liver showed that the extracts were able to offer protection against paracetamol-induced kidney and liver injuries. The extracts therefore have strong antioxidant and cytoprotection abilities.</p> Fakoya Akindele, Fredrick O. Obi ##submission.copyrightStatement## Thu, 19 Mar 2020 00:00:00 +0600 Rubidium Efflux Assay for the Determination of Calcium Activated Potassium Channel Activity <p>Rubidium efflux assay using flame atomic absorption spectrometry is employed in analyzing potassium channel activity. Calibration using standards of known R &nbsp;concentrations (10 - 100µM) in tubes was done at the beginning and end of each analysis. R &nbsp;standard curves were constructed from the data obtained from the analysis of the R standards in both the tubes and 96 well plates. HEK293 cells expressing the alpha subunit of BK channel were incubated with R &nbsp;for 4 hours after which the cells were washed and then treated with higher concentrations of KBS (50mM / 80mM) or NS1619 (0.003 - 100µM) for 10 minutes. The supernatant was removed and the cells lysed with 0.1%v/v triton. The percentage efflux was then determined from values obtained after analyzing the supernatant and lysate using flame atomic absorption spectrometer. The results showed that there was consistency during each analysis as the R &nbsp;standard curves constructed from the data obtained overlapped with no significant difference indicating precise calibration and internal validation. For the loaded cells (un-treated), the average concentration of R &nbsp;&nbsp;&nbsp;in the supernatant was 14.47µM while that in the lysate was 56.24µM and statistical analysis showed there was a significant difference with p&lt;0.0001. The treated cells with higher concentrations of KBS in comparison with 5.4mM KBS gave a percentage increase in R efflux of 47.8% for50mM KBS with significant different of p&lt;0.0001 and 80.11% increase with significant different of p&lt;0.05 for 80mM KBS. The treated cells with 0.1, 0.01 and 0.003µM NS1619 gave a percentage increase in efflux of 13.98%, 29.95% and 23.69% respectively. This research indicated the viability of using flame atomic absorption spectrometry for rubidium efflux assay to test for compounds activating effect on BK channel.</p> Zainab Gambo Ibrahim, Hussein A Saad Elrewey ##submission.copyrightStatement## Fri, 07 Aug 2020 00:22:53 +0600