Genome variations account for different response to three mineral elements between Medicago truncatula ecotypes Jemalong A17 and R108.

BACKGROUND: Resequencing can be used to identify genome variations underpinning many morphological and physiological phenotypes. Legume model plant Medicago truncatula ecotypes Jemalong A17 (J. A17) and R108 differ in their responses to mineral toxicity of aluminum and sodium, and mineral deficiency of iron in growth medium. The difference may result from their genome variations, but no experimental evidence supports this hypothesis. RESULTS: A total of 12,750 structure variations, 135,045 short insertions/deletions and 764,154 single nucleotide polymorphisms were identified by resequencing the genome of R108. The suppressed expression of MtAACT that encodes a putative aluminum-induced citrate efflux transporter by deletion of partial sequence of the second intron may account for the less aluminum-induced citrate exudation and greater accumulation of aluminum in roots of R108 than in roots of J. A17, thus rendering R108 more sensitive to aluminum toxicity. The higher expression-level of MtZpt2-1 encoding a TFIIIA-related transcription factor in J. A17 than R108 under conditions of salt stress can be explained by the greater number of stress-responsive elements in its promoter sequence, thus conferring J. A17 more tolerant to salt stress than R108 plants by activating the expression of downstream stress-responsive genes. YSLs (Yellow Stripe-Likes) are involved in long-distance transport of iron in plants. We found that an YSL gene was deleted in the genome of R108 plants, thus rendering R108 less tolerance to iron deficiency than J. A17 plants. CONCLUSIONS: The deletion or change in several genes may account for the different responses of M. truncatula ecotypes J. A17 and R108 to mineral toxicity of aluminum and sodium as well as iron deficiency. Uncovering genome variations by resequencing is an effective method to identify different traits between species/ecotypes that are genetically related. These findings demonstrate that analyses of genome variations by resequencing can shed important light on differences in responses of M. truncatula ecotypes to abiotic stress in general and mineral stress in particular.

Boron toxicity is alleviated by hydrogen sulfide in cucumber (Cucumis sativus L.) seedlings.

Boron (B) is an essential micronutrient for plants, which when occurs in excess in the growth medium, becomes toxic to plants. Rapid inhibition of root elongation is one of the most distinct symptoms of B toxicity. Hydrogen sulfide (H(2)S) is emerging as a potential messenger molecule involved in modulation of physiological processes in plants. In the present study, we investigated the role of H(2)S in B toxicity in cucumber (Cucumis sativus) seedlings. Root elongation was significantly inhibited by exposure of cucumber seedlings to solutions containing 5 mM B. The inhibitory effect of B on root elongation was substantially alleviated by treatment with H(2)S donor sodium hydrosulfide (NaHS). There was an increase in the activity of pectin methylesterase (PME) and up-regulated expression of genes encoding PME (CsPME) and expansin (CsExp) on exposure to high B concentration. The increase in PME activity and up-regulation of expression of CsPME and CsExp induced by high B concentration were markedly reduced in the presence of H(2)S donor. There was a rapid increase in soluble B concentrations in roots on exposure to high concentration B solutions. Treatment with H(2)S donor led to a transient reduction in soluble B concentration in roots such that no differences in soluble B concentrations in roots in the absence and presence of NaHS were found after 8 h exposure to the high concentration B solutions. These findings suggest that increases in activities of PME and expansin may underlie the inhibition of root elongation by toxic B, and that H(2)S plays an ameliorative role in protection of plants from B toxicity by counteracting B-induced up-regulation of cell wall-associated proteins of PME and expansins.

[Observation on effects of hepatitis B vaccine immunization for 12 years in children in Beijing].

OBJECTIVE: To evaluate the long-term protective effects of hepatitis B vaccine after immunizing to the children for 12 years in Beijing. METHODS: The multiple stratified cluster sampling was used in this epidemiological survey. The sampling children's blood serum HBsAg, anti-HBs and anti-HBc were checked and measured by the solid phase radioimmunoassay (SPRIA). The serological level of these index and the causes of the children with HBsAg positive were analyzed. RESULTS: There were 2,419 cases 3-12 years-old children immunized with the hepatitis B vaccine in infant period were surveyed and the total HBsAg positive rate was 0.52%. The vaccine protective rate was 88.45% (95% CI: 65.67%-97.89%). The total anti-HBc positive rate was 2.21%, being no statistical significance among the age groups. The average anti-HBs positive rate of 3-6 years-old children immunized with gene recombining vaccine was 38.79% and descending greatly following the age's dropping. The geometric means of anti-HBs serological titer (GMT) was 52.83 mIU/ml, showing no statistical significance among the age groups. The average anti-HBs positive rate of 6-12 years-old children immunized with the blood rooting vaccine was 50.79%. The geometric means of anti-HBs serological titer (GMT) was 61.51 mIU/ml. There were no statistical significances among the age groups. Among the HBsAg positive children, more than 50% of the children's mothers were HBsAg positive also. CONCLUSIONS: The protective effects given by immunization were significant after the hepatitis B vaccine vaccination for 12 years in Beijing. The booster immunization was not necessary, because the HBsAg positive rate didn't ascend obviously as the immunization time prolonging. As the anti-HBs positive rate of children who were immunized by the gene recombining vaccine might be descending following the age's dropping greatly, we should strengthen the serological surveillance of hepatitis B. The main cause that the children became the HBsAg carrier should be a vertical transmission.

Comparison of functional magnetic resonance imaging in cerebral activation between normal Uygur and Mandarin participants in semantic identification task.

PURPOSE: This study utilized blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) technology to study the activated cerebral regions in normal participants whose native language was Uyghur or Chinese. METHODS: We collected the fMRI data from 15 Uyghur-speaking volunteers and 15 Mandarin-speaking volunteers when executing the semantic identification task and compared the results of two groups. RESULTS: Statistically significant difference of brain activation was found primarily in the left anterior cingulate gyrus (BA23) and the midline precuneus (P<0.05). When performing the semantic identification task, the Uyghur group exhibited significant activation in these two regions, whereas the Chinese group demonstrated relatively weak activation in these areas. CONCLUSION: The cerebral regions activated by Uyghur and Chinese semantic identification are not identical, the dominant hemisphere for both languages is the left cerebral hemisphere. The left anterior cingulate gyrus might have a language function in Uyghur semantic processing.

[Series orthodontic treatment on teeth transposition of maxillary canine and lateral incisor].

OBJECTIVE: To explore the treatment on teeth transposition of maxillary canine and lateral incisor in order to improve the clinical treatment effect. METHODS: Eleven patients with transposition maxillary canine and lateral incisor were treated with the method: Expand space, artificial reverse occlusion of transpositional lateral incisor to give way, transpositional lateral canine distalization and controlling root, mesial movement of lateral incisor with tongue arch, interactive controlling roots and retention with tongue fixed retaining appliance. RESULTS: Eleven patients had satisfactory treatment effect, with tidy dentition and parallel teeth roots of transpositional canine and lateral incisor. CONCLUSION: Series orthodontic treatment on teeth transposition of maxillary canine and lateral incisor can effectively improve the clinical treatment effect and shorten the treatment time.