[Molecular mechanisms of meiotic recombination suppression in plants].

Meiotic recombination not only ensures the stability of chromosome numbers during the sexual reproduction in eukaryotes, but also shuffles the maternal and paternal genetic materials to generate genetic diversity in the gametes. Therefore, meiotic recombination is an important pathway for genetic diversity, which has been considered as a major driving force for species evolution and biodiversity in nature. In most eukaryotes, meiotic recombination is strictly limited, despite the large variation of physical genome size and chromosome numbers among species, but the mechanisms suppressing meiotic recombination remain elusive. Recently, several suppressors have been identified through the forward genetics screen, and revealed the functions and regulation pathways of these suppressors. In this review, we summarize the breakthrough discovery of meiotic recombination suppressors in plants based on research in Arabidopsis, with particular focus on the gene function and its regulation network to elucidate the molecular mechanisms of meiotic recombination suppression in plants.

Clinical analysis of 41 children's urinary calculus and acute renal failure / 中华儿科杂志

<p><b>OBJECTIVE</b>To analyze the treatment of acute renal failure caused by irrational drug use.</p><p><b>METHOD</b>Data of 41 cases of acute renal failure seen from July 2008 to June 2012 in our hospital were reviewed. Bilateral renal parenchymas diffuse echo was found enhanced by ultrasound in all cases. Calculus image was not found by X-ray. All children had medical history of using cephalosporins or others. Alkalinization of urine and antispasmodic treatment were given to all children immediately, 17 children were treated with hemodialysis and 4 children accepted intraureteral cannula placement.</p><p><b>RESULT</b>In 24 children who accepted alkalinization of urine and antispasmodic treatment micturition could be restored within 24 hours, in 11 children micturition recovered after only one hemodialysis treatment and 2 children gradually restored micturition after hemodialysis twice, 4 children who accepted intraureteral cannula immediately restored micturition. In all children micturition recovered gradually after a week of treatment. Ultrasound examination showed that 39 children's calculus disappeared totally and renal parenchymas echo recovered to normal. The residual calculi with diameter less than 5 mm were found in 2 children, but they had no symptoms. The children received potassium sodium hydrogen citrate granules per os and were discharged from hospital. Ultrasound showed calculus disappeared totally one month later.</p><p><b>CONCLUSION</b>Irrational drug use can cause children urolithiasis combined with acute renal failure, while renal dysfunction can reverse by drug withdrawal and early alkalinization of urine, antispasmodic treatment, intraureteral cannula or hemodialysis when necessary, most calculus can be expelled after micturition recovered to normal.</p>

Clinical features and changes of 5-hydroxytryptamine in children with vasovagal syncope / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate clinical features of childhood vasovagal syncope (VVS) and the possible relationship between changes of plasma and platelet 5-hydroxytryptamine (5-HT) and childhood VVS.</p><p><b>METHOD</b>Forty-one children who were diagnosed as VVS because of positive head-up tilt test (HUTT) in Capital Institute of Pediatrics were enrolled as HUT-positive group, while 36 healthy children as control group. Clinical features of all children were analyzed, and blood samples of all children were obtained. Plasma and platelet 5-HT was measured by enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULT</b>(1) The mean age of 41 VVS children was (10.5 +/- 1.8) years, and there were more girls than boys with the boys to girls ratio of 1:1.4. (2) Presyncopal symptoms occurred in 33 patients (80.4%), among whom dizziness had a high rate: 78.8%. (3) Commonly, there were some provocation factors before syncope, among which long-time standing was the most common one with the rate of 91.7%. (4) The mean time of positive response in BHUT and SNHUT were (20.6 +/- 8.6) minutes and (5.0 +/- 2.2) minutes, respectively. Duration of syncope was shorter than 5 minutes. (5) HUTT positive response included vasodepressor type with the rate of 61.0%, cardioinhibitory type with 14.6%, and mixed type with 24.4%. (6) There were no significant differences in baseline heart rate, systolic blood pressure and diastolic blood pressure between VVS children and healthy children. And it was the same among different types of VVS children. (7) There were no significant differences in plasma 5-HT between VVS group of baseline or HUTT-positive and control group [(27.51 +/- 1.32) microg/L vs.(27.28 +/- 2.48)microg/L, t = 0.518, P = 0.606; (27.51 +/- 1.32) microg/L vs.(28.05 +/- 1.40) microg/L, t = 2.044, P = 0.167]. There were no significant differences in platelet 5-HT concentration between VVS group of baseline and control group [(82.30 +/- 6.06) 10(9) ng/L vs. (79.88 +/- 5.79) 10(9) ng/L, t = 1.788, P = 0.780].(8) HUTT-positive platelet 5-HT concentration of VVS children was significantly higher than baseline value [(97.90 +/- 6.59) 10(9) ng/L vs. (82.30 +/- 6.06) 10(9) ng/L, t = 11.26, P = 0.00].</p><p><b>CONCLUSION</b>There were no significant changes in plasma 5-HT in children with VVS during baseline, syncope or pre-syncope, which suggests that plasma 5-HT might not be valuable for the prediction of syncope trigger. However, platelet 5-HT of VVS children was obviously higher during syncope and presyncope, which suggests that central serotonergic system might be involved in the pathogenesis of VVS.</p>

Comprehensive therapeutic protocol of electroacupuncture combined with Chinese herbs and rehabilitation training for treatment of cerebral infarction: a multi-center randomized controlled trial / 中国针灸

<p><b>OBJECTIVE</b>To evaluate the therapeutic effect of comprehensive therapeutic protocol of electroacupuncture combined with active-blood-and-dissolve-stasis herbs and rehabilitation training for cerebral infarction.</p><p><b>METHODS</b>A multi-center randomized controlled trial was done, three hundred and twenty cases were divided into four groups: electroacupuncture combined with active-blood and dissolve-stasis herbs and rehabilitation training group (group A), electroacupuncture combined with rehabilitation training group (group B), herbs combined with rehabilitation training group (group C) and rehabilitation training group (group D), 80 cases in each group. The following two groups of acupoints were used alternatively in electroacupuncture treatment: the first group including Vasomotor Area, Jianyu (LI 15), Biguan (ST 31), Hegu (LI 4) and Taichong (LR 3); the second group including Motor Area, Quchi (LI 11), Yanglingquan (GB 34) and Shenshu (BL 23). 20 mL Xiangdan injection and 250 mL 5% glucose injection or 250 mL 0.9% sodium chloride injection were used by intravenous drip in herbs treatment once a day. The rehabilitation training was performed by the professional physical therapist. Each group was treated with corresponding treatment protocol. The therapeutic effect was evaluated by index of the mortality or disability rate 3 months after the onset of disease. The intention to treat analysis (ITT) was used in data.</p><p><b>RESULTS</b>The mortality or handicap rate 3 months after the onset of disease of four groups were 17.5% (14/80) in group A, 22.5% (18/80) in group B, 40. 0% (32/80) in group C, and 31.3% (25/80) in group D, respectively. The group A has a best therapeutic effect (vs group C, group D, both P<0.05), and there was no adverse event.</p><p><b>CONCLUSION</b>The combined application of electroacupuncture, active-blood and dissolve-stasis herbs and rehabilitation training is a better treatment for cerebral infarction in clinic.</p>

Comparison of the reliability of two ELISA kits for detecting IgM antibody against hepatitis E virus / 中华预防医学杂志

<p><b>OBJECTIVE</b>To study the reliability of two ELISA kits for detecting IgM antibody against hepatitis E virus (HEV).</p><p><b>METHODS</b>Serum samples from 92 healthy subjects, 71 cases suspected of hepatitis E, 55 patients with confirmed diagnosis of acute hepatitis E, 50 individuals with rheumatoid factor (RF) positive and 54 persons with anti-HAV IgM positive were detected with three hepatitis E diagnostic kits. MP-IgM (MP, Singapore), Wantai-IgM and anti-HEV IgG (Wantai, China). HEV RNA was analyzed with RT-PCR in 52 of 71 cases suspected of hepatitis E.</p><p><b>RESULTS</b>In healthy subjects,cases suspected of hepatitis E and confirmed acute hepatitis E, the concordance between the two anti-HEV IgM reagents was 73.39% (160/218) and the significant differences in the positive rates of two assays were not observed [46.79% (102/218) vs 44.04% (96/218), chi2 = 0.62, P > 0.05]. Of 71 patients suspected of hepatitis E, the sensitivity for diagnosing acute hepatitis E of Wantai-IgM and MP-IgM were 83.08% (54/65) and 78.46% (51/65) (chi2 = 0.16, P > 0.05), respectively. Among those suspected of hepatitis E with HEV RNA positive, the sensitivity of Wantai-IgM was obviously higher than that of MP-IgM [(97.14%, 34/35) vs (74.29%, 26/35), chi2 = 4.9, P < 0.05]. 48 of 55 patients (87.27%) with confirmed diagnosis of hepatitis E were Wantai-IgM positive while 37 (67.27%) was MP-IgM positive (chi2 = 4.0, P < 0.05). The specificity of Wantai-IgM was higher than MP-IgM [100.00% (202/202) vs 89. 11% (180/202), chi2 = 20.05, P < 0.005]. RF and anti-HAV IgM might cause MP-IgM false positive without interference on Wantai-IgM.</p><p><b>CONCLUSION</b>Wantai-IgM should be a good ELISA kit for the diagnosis of acute hepatitis E.</p>

AtMTM1, a novel mitochondrial protein, may be involved in activation of the manganese-containing superoxide dismutase in Arabidopsis.

Mtm1p is essential for the posttranslational activation of manganese-containing superoxide dismutase (SOD2) in Saccharomyces cerevisiae; however, whether the same holds true for Arabidopsis thaliana is unknown. In this study, by using the yeast mtm1 mutant complementation method, we identified a putative MTM gene (AtMTM1, At4g27940) that is necessary for SOD2 activation. Further, analysis of SOD activity revealed that an SOD2 defect is rescued in the yeast mutant Y07288 harboring the AtMTM1 gene. Related mRNA-level analysis showed the AtMTM1 gene is induced by paraquat but not by hydrogen peroxide, which indicates that this gene is related to the superoxide scavenger SOD. In addition, an AtMTM1::GFP fusion construct was transiently expressed in the protoplasts, and it was localized to the mitochondria. Furthermore, sequence deletion analysis of AtMTM1 revealed that the code region (amino acid (aa) 60-198) of Mtm1p plays an important role in localization of the protein to the mitochondria. Regulation of AtMTM1 gene expression was analyzed using a fusion construct of the 1,766 bp AtMTM1 promoter and the GUS (beta-glucuronidase) reporter gene. The screen identified GUS reporter gene expression in the developing cotyledons, leaves, roots, stems, and flowers but not in the siliques. Our results suggest that AtMTM1 encodes a mitochondrial protein that may be playing an important role in activation of MnSOD1 in Arabidopsis.

AtNHX8, a member of the monovalent cation: proton antiporter-1 family in Arabidopsis thaliana, encodes a putative Li/H antiporter.

The Arabidopsis monovalent cation:proton antiporter-1 (CPA1) family includes eight members, AtNHX1-8. AtNHX1 and AtNHX7/SOS1 have been well characterized as tonoplast and plasma membrane Na+/H+ antiporters, respectively. The proteins AtNHX2-6 have been phylogenetically linked to AtNHX1, while AtNHX8 appears to be related to AtNHX7/SOS1. Here we report functional characterization of AtNHX8. AtNHX8 T-DNA insertion mutants are hypersensitive to lithium ions (Li+) relative to wild-type plants, but not to the other metal ions such as sodium (Na+), potassium (K+) and caesium (Cs+). AtNHX8 overexpression in a triple-deletion yeast mutant AXT3 that exhibits defective Na+/Li+ transport specifically suppresses sensitivity to Li+, but does not affect Na+ sensitivity. Likewise, AtNHX8 overexpression complemented sensitivity to Li+, but not Na+, in sos1-1 mutant seedlings, and increased Li+ tolerance of both the sos1-1 mutant and wild-type seedlings. Results of Li+ and K+ measurement of loss-of-function and gain-of-function mutants indicate that AtNHX8 may be responsible for Li+ extrusion, and may be able to maintain K+ acquisition and intracellular ion homeostasis. Subcellular localization of the AtNHX8-enhanced green fluorescent protein (EGFP) fusion protein suggested that AtNHX8 protein is targeted to the plasma membrane. Taken together, our findings suggest that AtNHX8 encodes a putative plasma membrane Li+/H+ antiporter that functions in Li detoxification and ion homeostasis in Arabidopsis.

A novel drought-inducible gene, ATAF1, encodes a NAC family protein that negatively regulates the expression of stress-responsive genes in Arabidopsis.

NAC proteins are plant-specific transcriptional regulators. ATAF1 was one of the first identified NAC proteins in Arabidopsis. In present study, we characterized the ATAF1 expression and biological function in response to water deficit stress. ATAF1 mRNA expression was strongly induced by dehydration and abscisic acid (ABA) treatment, but inhibited by water treatment, suggesting a general role in drought stress responses. Transient expression analysis in onion epidermal cells indicated the nuclear localization for the ATAF1::GFP fusion protein. Yeast transactivation analysis showed that ATAF1 had ability to activate reporter gene expression. Furthermore, domain deletion analysis revealed that the ATAF1 transactivation activity was conferred by its C-terminal domain. When ATAF1 gene was knocked out by T-DNA insertions, Arabidopsis ataf1-1 and ataf1-2 mutants displayed a recovery rate about seven times higher than wild-type plants in drought response test. This ataf1 phenotype was coincident with the enhanced expression of stress responsive marker genes, such as COR47, ERD10, KIN1, RD22 and RD29A under drought stress. Above evidences suggest that ATAF1, as a transcriptional regulator, negatively regulates the expression of stress responsive genes under drought stress in Arabidopsis.