VOZ1 and VOZ2 transcription factors regulate arsenic tolerance and distribution in rice and Arabidopsis.

Rice is the major source of arsenic (As) intake in humans, as this staple crop readily accumulates As in the grain. Identifying the genes and molecular mechanisms underlying As accumulation and tolerance is a crucial step toward developing rice with reduced As levels. We identified 25 rice genes that improve As tolerance in yeast cells by expressing a complementary DNA (cDNA) library generated from As-treated rice roots. Among them, a zinc finger-type transcription factor VASCULAR PLANT ONE- ZINC FINGER 1 (OsVOZ1) (OsVOZ1) conferred the most pronounced As tolerance. OsVOZ1 inhibits As accumulation in yeast via activation of As efflux transporter Acr3p by post-transcriptional modification in yeast. The Arabidopsis voz1 voz2 double-knockout mutant exhibited As hypersensitivity, altered As concentrations in various tissues, and reduced As transport activity via the phloem. Arabidopsis and rice VOZs were highly expressed in phloem cells in various tissues, which are critical for As distribution in plant tissues. The double-knockdown and single-knockout plants of OsVOZ1 and OsVOZ2 reduced As accumulation in their seeds. These findings suggest that rice and Arabidopsis VOZs regulate the translocation of As into tissues by regulating the phloem loading of this element.

[Effect of litchi seed aqueous extracts on learning and memory obstacles induced by D-galactose in mice and its mechanism].

OBJECTIVE: To investigate the improving effect of Litchi Seed Aqueous Extracts on learning and memory obstacles model and its mechanism. METHODS: The learning and memory obstacles model was incluced by subcutoneous injection of D-galactose (500 mg/kg) for 8 weeks. The model group and treatment groups were given huperzine A (0.4 mg/kg) and Litchi Seed Aqueous Extracts (15,60 g/kg) respectively for 4 weeks by ig at the 5th week. After huperzine A and Litchi Seed Aqueous Extracts treatment for 4 weeks, water maze test was used to determine the ability of mice's spatial learning and memory. The contents of advanced glycation end products (AGEs) in serum, the content of nitric oxide (NO) and acetylcholine (Ach), the activity of nitric oxide synthase (NOS) and acetylcholinesterase (AchE) in the brain tissue were detected. RESULTS: Litchi Seed Aqueous Extracts significantly ameliorated the learning and memory ability in mice, decreased the level of AGEs in serum, and reduced the content of NO and activity of NOS in brain tissues. No significantly influence was observed for the Ach and Ach-E in brain tissues. CONCLUSION: Litchi Seed Aqueous Extracts possesses improving the learning and memory effects on the model mice induced by D-galactose, which may be related to inhibiting too much AGEs and NO formation and reducing damage in the brain cells.

Ameliorative effect of berberine on renal damage in rats with diabetes induced by high-fat diet and streptozotocin.

Berberine (BBR) is one of the main constituents in Rhizoma coptidis and it has widely been used for the treatment of diabetic nephropathy. The aims of the study were to investigate the effects and mechanism of action of berberine on renal damage in diabetic rats. Diabetes and hyperglycaemia were induced in rats by a high-fat diet and intraperitoneal injection of 40 mg/kg streptozotocin (STZ). Rats were randomly divided into 5 groups, such as i) control rats, ii) untreated diabetic rats iii) 250 mg/kg metformin-treated, iv and v) 100 and 200 mg/kg berberine-treated diabetic rats and treated separately for 8 weeks. The fasting blood glucose, insulin, total cholesterol, triglyceride, glycosylated hemoglobin were measured in rats. Kidneys were isolated at the end of the treatment for histology, Western blot analysis and estimation of malonaldehyde (MDA), superoxide dismutase (SOD) and renal advanced glycation endproducts (AGEs). The results revealed that berberine significantly decreased fasting blood glucose, insulin levels, total cholesterol, triglyceride levels, urinary protein excretion, serum creatinine (Scr) and blood urea nitrogen (BUN) in diabetic rats. The histological examinations revealed amelioration of diabetes-induced glomerular pathological changes following treatment with berberine. In addition, the protein expressions of nephrin and podocin were significantly increased. It seems likely that in rats berberine exerts an ameliorative effect on renal damage in diabetes induced by high-fat diet and streptozotocin. The possible mechanisms for the renoprotective effects of berberine may be related to inhibition of glycosylation and improvement of antioxidation that in turn upregulate the expressions of renal nephrin and podocin.