An exercise to estimate differential gene expression in human cells

Naringin enhances reverse cholesterol transport in high fat/low streptozocin induced diabetic rats

Naringin, a citrus-derived flavonoid with antihyperglycemic, antihyperlipidemic, and antioxidant properties, is reported to be a useful nutraceutical in the management of diabetes and its complications. This study investigated the mechanism of antiatherogenic properties of naringin in type 2 diabetes (T2DM) using high fat-low streptozocin rat model of T2DM. Rats were treated daily with 50, 100 and 200 mg/kg naringin orally for 21days. Levels of biomarkers of T2DM, lipid profile and activity of paraoxonase (PON) were assayed spectrophotometrically. The levels of expression of hepatic 3-hydroxy-3-methyl-glutaryl-CoA reductase (Hmgcr), scavenger receptor class B member 1 (Scarb1), aryl hydrocarbon receptor (Ahr), hepatic Lipase (Lipc), and lecithin-cholesterol acyltransferase (Lcat) were assessed using relative reverse transcriptase polymerase chain reaction technique. Naringin treatment resulted in a dose-dependent significant (p < 0.05) decrease in the levels of plasma cholesterol and triglyceride from 84.84 ± 1.62 to 55.59 ± 1.50 mg/dL and 123.03 ± 15.11 to 55.00 ± 0.86 mg/dL, respectively, at 200 mg/kg naringin. In the liver, Scarb1 and Ahr were significantly (p < 0.05) upregulated at 200 mg/kg naringin while Lipc and Lcat were significantly (p < 0.05) upregulated by 50 mg/kg naringin. T2DM-induced decrease in PON activities in the plasma, liver and HDL was significantly (p < 0.05) reversed by 200 mg/kg naringin treatment. These genes play critical roles in reverse cholesterol transport and hence our results showed that the antiatherogenic property of naringin in T2DM involves enhancement of reverse cholesterol transport and PON activity.

A practical home-made microcentrifuge for teaching purposes

We report a practical home-made microcentrifuge to be used for teaching purposes. It was made using a salad spinner and two polymerase chain reaction (PCR) tubes racks. It can accommodate 2 standard size 96-well plates or 24 strips or up to 192 microfuge tube. The centrifuge is hand-operated and is ideal for short spin down purposes.

PCR cloning of partial nbs sequences from grape (Vitis aestivalis Michx)

Plants defend themselves against pathogens via the expressions of disease resistance (R) genes. Many plant R gene products contain the characteristic nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains. There are highly conserved motifs within the NBS domain which could be targeted for polymerase chain reaction (PCR) cloning of R genes. Here, we report a 4-week undergraduate laboratory exercise that mimics the research environment to PCR-clone partial nbs sequences using degenerate primers corresponding to the phosphate-binding loop (P-loop) and GLPL motifs within the NBS domain of potential R gene products from the North American grape, Vitis aestivalis Michx. Students were able to complete the laboratory procedures successfully and obtained four different clones, among which three are new. Through the laboratory exercise, students learned a variety of important molecular techniques including genomic DNA isolation, DNA quantification, PCR, agarose gel electrophoresis, DNA extraction from agarose gel, ligation, bacterial transformation, and plasmid DNA isolation and purification. They also used currently available web-based bioinformatic programs for sequence analysis. The laboratory exercise provides students the hands-on experience on PCR cloning and shows them how it is done in a research environment. The clones obtained may be further tested for their potential use as markers to differentiate resistant cultivars from the susceptible ones, a useful tool in breeding programs.