Allelopathic inhibition of the extracts of Landoltia punctata on Microcystis aeruginosa.

To study the allelopathic effect of the extracts of Landoltia punctata, the changes of cell density of Microcystis aeruginosa were measured. The anti-algae allelopathic effect of different organic solvent extracts of L. punctata was evaluated, and the physiological, biochemical indexes were determined to discuss the mechanism of algal inhibition. The results showed that the petroleum ether, dichloromethane and ethyl acetate extracts showed various inhibitory effects on M. aeruginosa. Among them, ethyl acetate extract was the most strongly allelopathic part with the semi-effect concentration(EC50) of 59.6 mg L-1, the central polarity part of inhibitory activity. The contents of chlorophyll a(Chl a) and phycobiliproteins(PBPs) of M. aeruginosa were decreased under the concentration of 200 mg L-1 ethyl acetate extract, which indicated that the photosynthesis of M. aeruginosa was inhibited. The consent of microcystins was lower compared to control under 200 mg L-1. The contents of superoxide dismutase(SOD), malondialdehyde(MDA) and hydrogen peroxide(H2O2) of cell pellets were firstly increased and then decreased, which suggested that the algal cells were seriously damaged by oxidation. The results indicated that the extracts of L. punctata had inhibitory effect on M. aeruginosa, and the ethyl acetate extract was the central part of the inhibitory substances, which affected photosynthesis and caused peroxidation damage to inhibit cell proliferation. These findings will be helpful for exploration and application of allelopathic effects of L. punctata in harmful algae control.

Effect of allisartan on blood pressure and left ventricular hypertrophy through Kv1.5 channels in hypertensive rats.

BACKGROUND: The objective of the present work was to study the anti-hypertensive effect of allisartan on blood pressure (BP) and in facilitating left ventricular remodeling through voltage-gated potassium channels (Kv) 1.5 channels. METHODS: A total of 30 SD rats were randomly divided into sham operation group, hypertension control group, and allisartan treatment group. Hypertension was induced by renal artery stenosis. The animals of treatment group were administered with allisartan once a day at a dose of 30 mg/kg body weight through an oral gavage for 4 weeks. The heart function of animals post 4 weeks of treatment was evaluated by echocardiography, and the degree of ventricular hypertrophy and cardiomyocyte hypertrophy were evaluated by histomorphology. The expression of Kv1.5 is detected by real-time quantitative polymerase chain reaction while Western blotting was used to detect the protein expression. RESULTS: Four weeks after renal artery stenosis, a significant difference was observed in the whole heart ratio, left heart ratio, and cardiomyocyte area between allisartan treatment group and the hypertension control group (P< .01). A significant decrease in BP of allisartan treatment group compared to hypertension control group (P< .01) was observed. The expression of Kv1.5 mRNA was increased significantly (P< .01) in allisartan treatment group compared to hypertension control group. Western blot analysis also confirmed the increased expression of Kv1.5 channel. CONCLUSION: The results showed that allisartan lowers BP and improves left ventricular remodeling through increased expression of Kv1.5 mRNA.

Microarray analysis of differentially expressed microRNAs in allergic rhinitis.

BACKGROUND: Allergic rhinitis (AR) is a common disease characterized by chronic inflammation of the nasal mucosa, but we have not fully understood the mechanism responsible for the development of AR. MicroRNAs (miRNAs) are short endogenous noncoding RNAs regulating protein translation through a mechanism known as RNA interference. To understand the molecular mechanisms of miRNA involved in the pathogenesis of AR, expressed miRNAs in AR were investigated through genomewide microarray analysis. METHODS: Mammalian miRNA microarrays containing whole human mature and precursor miRNA sequences were used for analyzing eight samples of nasal mucosa of AR and eight samples of nonallergic patients. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) of some different expressed miRNAs was used to confirm the array results. RESULTS: The miRNA microarray chip analysis identified 421 miRNAs differentially expressed in the nasal mucosa of AR, and a total of 9 miRNAs were identified in the AR group with twofold change compared with control samples (p < 0.05). These included up-regulated miRNAs, hsa-hsa-miR-7, and hsa-miRPlus-E1194, and down-regulated miRNAs, hsa-miR-498, hsa-miR-187, hsa-miR-874, hsa-miR-143, hsa-miR-886-3p, hsa-miR-224, and hsa-miR-767-5p. RT-PCR results also confirmed that part of differentially expressed miRNAs as hsa-miR-224, hsa-miR-187, and hsa-miR-143 were down-regulated in AR. CONCLUSION: The report indicated that many miRNA expressions were altered in AR and differentially expressed miRNAs appear to be involved in the development of AR. The study of miRNAs may lead to a better understanding about the roles of identified miRNAs in the pathogenesis of AR; this would be considered in future therapeutic strategies.