Transcriptome analysis of tea (Camellia sinensis) leaves in response to ammonium starvation and recovery.

The tea plant is a kind of ammonium-preferring crop, but the mechanism whereby ammonium (NH4 +) regulate its growth is not well understood. The current study focused on the effects of NH4 + on tea plants. Transcriptomic analysis was performed to investigate the early- and late-stage NH4 + deprivation and resupply in tea plants shoots. Through short- and long-term NH4 + deficiency, the dynamic response to NH4 + stress was investigated. The most significant effects of NH4 + deficiency were found to be on photosynthesis and gene ontology (GO) enrichment varied with the length of NH4 + deprivation. Enriched KEGG pathways were also different when NH4 + was resupplied at different concentrations which may indicate reasons for tolerance of high NH4 + concentration. Using weighted gene co-expression network analysis (WGCNA), modules related to significant tea components, tea polyphenols and free amino acids, were identified. Hence, NH4 + could be regarded as a signaling molecule with the response of catechins shown to be higher than that of amino acids. The current work represents a comprehensive transcriptomic analysis of plant responses to NH4 + and reveals many potential genes regulated by NH4 + in tea plants. Such findings may lead to improvements in nitrogen efficiency of tea plants.

Genome-wide identification, characterization, and expression analysis of the ammonium transporter gene family in tea plants (Camellia sinensis L.).

As a preferred nitrogen form, ammonium (NH4 + ) transport via specific transporters is particularly important for the growth and development of tea plants (Camellia sinensis L.). However, our understanding of the functions of the AMT family in tea plants is limited. We identified and named 16 putative AMT genes according to phylogenetic analysis. All CsAMT genes were divided into three groups, distributed on 12 chromosomes with only one segmental duplication repetition. The CsAMT genes showed different expression levels in different organs, and most of them were expressed mainly in the apical buds and roots. Complementation analysis of yeast mutants showed that CsAMTs restored the uptake of NH4 + . This study provides insights into the genome-wide distribution and spatial expression of AMT genes in tea plants.

[Comparative study of antegrade and retrograde intramedullary nailing for the treatment of humeral shaft fractures].

OBJECTIVE: To compare therapeutic effects between antegrade intramedullary nailing and retrograde intramedullary nailing for the treatment of humeral shaft fractures. METHODS: From March 1999 to October 2006, 105 patients with humeral shaft fractures were treated with locked intramedullary nail and were adequately followed up. There were 82 antegrade nailing and 23 retrograde nailing. The follow-up parameters included operation time, blood loss,fracture healing rate, healing time, complications, Constant-Murley shoulder score and Mayo elbow performance score. RESULTS: The mean follow-up period was 31.2 months. Antegrade intramedullary nailing had significantly less blood loss than that in retrograde intramedullary nailing (P=0.002). The differences in operation time, complications, healing time and bone healing rate between he two groups had no statistical significance. Complications in the antegrade intramedullary nail group included 4 patients with nonunions, 1 patient with radial nerve palsy, and 8 patients with shoulder pains and decrement in shoulder range of motion. Complications in the retrograde intramedullary nail group included 1 patient with radial nerve palsy and 3 patients with iatrogenic fractures. For shoulder joints,the difference in the average Constant-Murley shoulder score between the two groups was statistically significant (P=0.04). For elbow joints, the average postoperative Mayo elbow performance score between these two approaches did not differ significantly. CONCLUSION: Both the antegrade intramedullary nailing and the retrograde intramedullary nailing are good alternatives for the treatment of humeral shaft fractures. Because of higher incidence of iatrogenic fractures, the insertion point of retrograde intramedullary nailing should be carefully prepared. With antegrade insertion, it important to bury the humeral nail below the rotator cuff to prevent the subacromial impingement, and the rotator cuff should be carefully repaired to avoid shoulder pain and improve shoulder function.

[Antibiotic-PMMA beads combined with external fixator for treating the infected fracture nonunion].

OBJECTIVE: To investigate the effects of antibiotic-PMMA (polymethyl-methacrylate) beads combined with external fixator in treatment of infected fracture nonunion. METHODS: Twenty-two cases of infected fracture-nonunions were reviewed involving 20 male and 2 female with an average age of 34.68 years (ranging 21 to 74 years). The data consisted of 9 cases of tibial fractures, 2 distal fractures of the femur, 6 femoral shaft fractures, 3 intertrochanteric fracture of the femur and 2 humeral shaft fractures. The procedure included thorough debridement to wipe out dead bone and granulation tissue, then antibiotic-PMMA bead chains imbedded into the dead space. One week later, secondary debridement was performed, antibiotic-PMMA bead chains were changed according to result of bacterial culture and susceptibility test, and fractures were stabilized with external fixator. Three months after debridement, antibiotic-PMMA bead chains were taken out and bone graft with autogenous iliac cancellous bone chips was performed. RESULTS: The mean follow-up period was 19.98 months (ranging 15 to 28 months). Infection was controlled in 20 cases. One tibial fracture and 1 intertrochanteric fracture of the femur needed repeated debridement 2 and 3 months after bone grafting respectively,because of infection recurrence and sinus formation. All 22 cases achieved bony union averaged 15.09 weeks after bone grafting with a range of 8 to 24 weeks. CONCLUSION: Thorough debridement, imbedding antibiotic-PMMA bead chains combined with external fixator and staged bone grafting has proven to be effective and simple for treatment of infected fracture nonunion. The antibiotic bead delivers high tissue levels,obliterates dead space, aids bone repair.