Circadian rhythm response and its effect on photosynthetic characteristics of the Lhcb family genes in tea plant.

BACKGROUND: The circadian clock, also known as the circadian rhythm, is responsible for predicting daily and seasonal changes in the environment, and adjusting various physiological and developmental processes to the appropriate times during plant growth and development. The circadian clock controls the expression of the Lhcb gene, which encodes the chlorophyll a/b binding protein. However, the roles of the Lhcb gene in tea plant remain unclear. RESULTS: In this study, a total of 16 CsLhcb genes were identified based on the tea plant genome, which were distributed on 8 chromosomes of the tea plant. The promoter regions of CsLhcb genes have a variety of cis-acting elements including hormonal, abiotic stress responses and light response elements. The CsLhcb family genes are involved in the light response process in tea plant. The photosynthetic parameter of tea leaves showed rhythmic changes during the two photoperiod periods (48 h). Stomata are basically open during the day and closed at night. Real-time quantitative PCR results showed that most of the CsLhcb family genes were highly expressed during the day, but were less expressed at night. CONCLUSIONS: Results indicated that CsLhcb genes were involved in the circadian clock process of tea plant, it also provided potential references for further understanding of the function of CsLhcb gene family in tea plant.

Differential Response of MYB Transcription Factor Gene Transcripts to Circadian Rhythm in Tea Plants (Camellia sinensis).

The circadian clock refers to the formation of a certain rule in the long-term evolution of an organism, which is an invisible 'clock' in the body of an organism. As one of the largest TF families in higher plants, the MYB transcription factor is involved in plant growth and development. MYB is also inextricably correlated with the circadian rhythm. In this study, the transcriptome data of the tea plant 'Baiyeyihao' were measured at a photoperiod interval of 4 h (24 h). A total of 25,306 unigenes were obtained, including 14,615 unigenes that were annotated across 20 functional categories within the GO classification. Additionally, 10,443 single-gene clusters were annotated to 11 sublevels of metabolic pathways using KEGG. Based on the results of gene annotation and differential gene transcript analysis, 22 genes encoding MYB transcription factors were identified. The G10 group in the phylogenetic tree had 13 members, of which 5 were related to the circadian rhythm, accounting for 39%. The G1, G2, G8, G9, G15, G16, G18, G19, G20, G21 and G23 groups had no members associated with the circadian rhythm. Among the 22 differentially expressed MYB transcription factors, 3 members of LHY, RVE1 and RVE8 were core circadian rhythm genes belonging to the G10, G12 and G10 groups, respectively. Real-time fluorescence quantitative PCR was used to detect and validate the expression of the gene transcripts encoding MYB transcription factors associated with the circadian rhythm.

Transarterial chemoembolization extends long-term survival in patients with unresectable hepatocellular carcinoma.

The long-term survival benefit of treating unresectable hepatocellular carcinoma (HCC) patients with transarterial chemoembolization (TACE) rather than conservative treatment remains controversial. This retrospective case-control study evaluated the survival of patients with unresectable HCC treated with TACE, relative to that of patients who received best supportive care.From January 2002 to December 2010, 522 of 2386 consecutive patients with unresectable HCC were enrolled. Patients were treated with TACE (n = 347) or best supportive care (non-TACE; n = 175). A survival analysis compared the survival of the 2 groups, as well as only those at Barcelona Clinic Liver Cancer Classification (BCLC)-C and Child-Pugh-B (39 TACE, 61 non-TACE).The median follow-up was 5 months (0.15-106 months).The overall median survival of the TACE group (8.0 months) was significantly longer than that of the non-TACE (2.0 months; P ≤ .01). Of the patients at BCLC-C and Child-Pugh-B, the overall median survivals of the TACE and non-TACE patients were 6.0 and 2.0 months, respectively (P ≤ .01); and the 1, 2, 3, 5, and 8-year overall survival rates were significantly superior in the TACE group (P ≤ .01). For all the patients, the independent predictors of survival were treatment modalities, portal vein tumor thrombosis, alpha-fetoprotein, and BCLC stage. Regarding the TACE patients, contributors to prognosis were portal vein tumor thrombosis, alpha-fetoprotein level, and the number of TACE procedures.TACE for unresectable HCC was associated with longer survival compared with best supportive care, especially for patients at BCLC-C and Child-Pugh-B.