Isolation and expression analysis of four HD-ZIP III family genes targeted by microRNA166 in peach.

MicroRNA166 (miR166) is known to have highly conserved targets that encode proteins of the class III homeodomain-leucine zipper (HD-ZIP III) family, in a broad range of plant species. To further understand the relationship between HD-ZIP III genes and miR166, four HD-ZIP III family genes (PpHB14, PpHB15, PpHB8, and PpREV) were isolated from peach (Prunus persica) tissue and characterized. Spatio-temporal expression profiles of the genes were analyzed. Genes of the peach HD-ZIP III family were predicted to encode five conserved domains. Deduced amino acid sequences and tertiary structures of the four peach HD-ZIP III genes were highly conserved, with corresponding genes in Arabidopsis thaliana. The expression level of four targets displayed the opposite trend to that of miR166 throughout fruit development, with the exception of PpHB14 from 35 to 55 days after full bloom (DAFB). This finding indicates that miR166 may negatively regulate its four targets throughout fruit development. As for leaf and phloem, the same trend in expression level was observed between four targets and miR166 from 75 to 105 DAFB. However, the opposite trend was observed for the transcript level between four targets and miR166 from 35 to 55 DAFB. miRNA166 may negatively regulate four targets in some but not all developmental stages for a given tissue. The four genes studied were observed to have, exactly or generally, the same change tendency as individual tissue development, a finding that suggests genes of the HD-ZIP III family in peach may have complementary or cooperative functions in various tissues.

Potassium contributes to zinc stress tolerance in peach (Prunus persica) seedlings by enhancing photosynthesis and the antioxidant defense system.

Zinc (Zn) is considered to be a major industrial pollutant because excessive amounts can impair plant growth. In this paper, we found that peach 'Yoshihime' seedlings are promising Zn tolerant plants. However, heavy Zn toxicity (2 mM) damaged plant performance by disrupting biochemical processes, including photosynthesis, proline production, and K(+) nutrition. Notably, elevated external K(+) supply (10 mM) alleviated peach seedlings from Zn toxicity, evidenced by enhanced photosynthesis, antioxidant defense systems, and plant K(+) nutritional status. Moreover, the transcript levels of KUP (K(+) uptake) genes involved in K(+) acquisition, transport, and homeostasis were significantly upregulated following supply of sufficient K(+) upon Zn toxicity. In general, K(+) favorably contributes to improvements in internal K(+) homeostasis, via the help of K(+) transporters, further protecting plant photosynthesis and the antioxidative defense system. Our findings further benefit the study of the mechanisms underpinning heavy metal tolerance in woody plants.

Toll-like receptor 4 promotes fibrosis in bleomycin-induced lung injury in mice.

The specific role of Toll-like receptor 4 (TLR4) in bleomycin-induced lung fibrosis of mice, a model of human idiopathic pulmonary fibrosis, has not been characterized. We injected bleomycin intratracheally into TLR4 knockout (TLR4(-/-)) and wild-type (WT) mice. Twenty-one days after injection, mice were sacrificed and their lungs were harvested for pathological, hydroxyproline, mRNA expression, and collagen I analyses. Body weight changes and mortality were observed. Light microscopy showed that lung fibrosis was minimal in TLR4(-/-) compared to that in WT mice on day 21 after bleomycin instillation. The Ashcroft score was significantly lower in TLR4(-/-) than in WT mice (3.667 ± 0.730 vs 4.945 ± 0.880, P < 0.05). Hydroxyproline content was significantly lower in TLR4(-/-) than in WT mice on day 21 after bleomycin injection (0.281 ± 0.022 vs 0.371 ± 0.047, P < 0.05). Compared to WT mice, bleomycin-treated TLR4(-/-) mice expressed significantly lower type I collagen mRNA levels (mesenchymal marker; 11.069 ± 2.627 vs 4.589 ± 1.440, P < 0.05). Collagen I was significantly lower in TLR4(-/-) than in WT mice (0.838 ± 0.352 vs 2.427 ± 0.551, P < 0.05). Bleomycin-treated TLR4(-/-) mice had a significantly lower mortality rate on day 21 than WT mice (33 vs 75%, P < 0.05). Body weight reduction was lower in TLR4(-/-) mice than in WT mice; this difference was not statistically significant (-3.735 ± 5.276 vs -6.698 ± 3.218, P > 0.05). Thus, bleomycin-induced pulmonary fibrosis is TLR4-dependent and TLR4 promoted fibrosis in bleomycin-challenged mice.

Torasemide reduces dilated cardiomyopathy, complication of arrhythmia, and progression to heart failure.

The aim of this study was to analyze the incidence and types of arrhythmia and their relationship with the severity and prognosis of chronic heart failure (CHF) in patients with dilated cardiomyopathy (DCM), and to investigate the therapeutic effect of torasemide versus furosemide on CHF and incidence of arrhythmia. DCM patients with NYHA cardiac function II-IV were continuously monitored using a 24-h dynamic electrocardiogram (Holter), and arrhythmia incidence was analyzed by computer automatic analysis combined with manual assessment. In total, 125 participants were evenly divided into two groups: torasemide group which received 10 mg oral torasemide once daily) and regular anti-heart failure treatment (N=65), and furosemide group which received torasemide (20 mg once daily orally) and regular antiheart failure treatment (N=60). Another 60 normal healthy persons served as the normal control group. Incidence and severity of arrhythmia increased when degree of CHF was elevated. Size of left atrium was related to atrial fibrillation and size of left ventricle was related to malignant arrhythmia. At 3 months after treatment, cardiac function in both groups improved and incidence and severity of arrhythmia in both groups were reduced. However, left ventricular ejection fraction (LVEF) was higher in the torasemide group than in the furosemide group, while incidence of arrhythmia was lower in the torasemide group. Arrhythmias frequently occurred in patients with DCM and HF. Type of cardiac arrhythmia is closely related to ventricular enlargement and cardiac function grade. Torasemide is better for improving cardiac function to reduce arrhythmia and CHF compared to furosemide.