Banana MaSPL16 Modulates Carotenoid Biosynthesis during Fruit Ripening through Activating the Transcription of Lycopene ß-Cyclase Genes.

Carotenoids are a class of bioactive compounds that exhibit health-promoting properties for humans, but their regulation in bananas during fruit ripening remains largely unclear. Here, we found that the total carotenoid content continued to be elevated along the course of banana ripening and peaked at the ripening stage followed by a decrease, which is presumably caused by the transcript abundances of carotenoid biosynthetic genes MaLCYB1.1 and MaLCYB1.2. Moreover, a ripening-inducible transcription factor MaSPL16 was characterized, which was a nuclear protein with transactivation activity. Transient transformation of MaSPL16 in banana fruits led to enhanced transcript levels of MaLCYB1.1 and MaLCYB1.2 and hence the total carotenoid accumulation. Importantly, MaSPL16 stimulated the transcription of MaLCYB1.1 and MaLCYB1.2 through directly binding to their promoters. Collectively, our findings indicate that MaSPL16 behaves as an activator to modulate banana carotenoid biosynthesis, which may provide a new target for molecular improvement of the nutritional and bioactive qualities of agricultural crops that accumulate carotenoids.

MaBZR1/2 act as transcriptional repressors of ethylene biosynthetic genes in banana fruit.

Banana fruit (Musa acuminate L.) ripening is a complex genetical process affected by multiple phytohormones and expression of various genes. However, whether plant hormone brassinosteroid (BR) is involved in this process remains obscure. In this work, three genes that encode BR core signaling components brassinazole resistant (BZR) proteins, namely MaBZR1 to MaBZR3, were characterized from banana fruit. MaBZR1-MaBZR3 exhibited both nuclear and cytoplasmic localization and behaved as transcription inhibitors. Expression analysis showed that MaBZR1/2/3 were continuously decreased as fruit ripening proceeded, indicating their negative roles in banana ripening. Moreover, gel shift and transient expression assays demonstrated that MaBZR1/2 could suppress the transcription of ethylene biosynthetic genes, including MaACS1, MaACO13 and MaACO14, which increased gradually during the banana ripening, via specifically binding to CGTGT/CG sequence in their promoters. Importantly, exogenous application of BRs promotes banana ripening, which is presumably due to the accelerated expression of MaACS1 and MaACO13/14, and consequently the ethylene production. Our study indicates that MaBZR1/2 act as transcriptional repressors of ethylene biosynthetic genes during banana fruit ripening.

Prognostic Impact of Fasting Plasma Glucose on Mortality and Re-Hospitalization in Patients with Acute Heart Failure.

BACKGROUND: The impact of fasting plasma glucose (FPG) on survival outcomes in patients with acute heart failure (HF) is unclear, and the relationship between intensity of glycemic control of FPG in diabetes mellitus (DM) patients and HF prognosis remains uncertain. This retrospective study aimed to evaluate the prognostic impact of FPG in patients with acute HF. METHODS: A total of 624 patients hospitalized with acute HF from October 2000 to April 2014 were enrolled in this study. All patients were stratified by three groups according to their admission FPG levels (i.e., DM, impaired fasting glucose [IFG], and non-DM). All-cause and cardiovascular mortality was the primary end point, and HF re-hospitalization was the secondary end point during follow-up period. RESULTS: A total of 587 patients were included in final analysis. The all-cause mortality rates of patients with DM, IFG, and non-DM were 55.5%, 40.3%, and 39.2%, with significant difference (P = 0.001). Moreover, compared with those with IFG (34.3%) and non-DM (32.6%), patients with DM had significantly higher rate of cardiovascular mortality (45.1%). Multiple Cox regression analysis showed that DM as well as IFG was related to all-cause mortality (DM: hazard ratio [HR] = 1.936, P < 0.001; IFG: HR = 1.672, P = 0.019) and cardiovascular mortality (DM: HR = 1.739, P < 0.001; IFG: HR = 1.817, P = 0.013). However, they were both unrelated to HF re-hospitalization. DM patients with strictly controlled blood glucose (FPG <3.9 mmol/L) had higher all-cause mortality than patients with non-DM, IFG, and DM patients with moderately controlled glucose (3.9 mmol/L≤ FPG <7.0 mmol/L). Likewise, both the primary end point and secondary end point were found to be worse in DM patients with poorly controlled blood glucose (FPG ≥7.0 mmol/L). CONCLUSIONS: IFG and DM were associated with higher all-cause mortality and cardiovascular mortality in patients with acute HF. The association between mortality and admission FPG in DM patients with acute HF appeared U-shaped.

Identification of Two Transcriptional Activators MabZIP4/5 in Controlling Aroma Biosynthetic Genes during Banana Ripening.

The transcriptional regulation of aroma formation genes remains poorly understood in the banana. In this work, we found that the expressions of a subset of aroma biosynthetic genes including MaOMT1, MaMT1, MaGT1, MaBCAT1, MaACY1, MaAGT1, and BanAAT, as well as two bZIP genes, MabZIP4 and MabZIP5, were down-regulated when prestored at 7 °C compared to those prestored at 22 °C during the ripening process of banana. Furthermore, MabZIP4 and MabZIP5 were shown to be able to activate the transcription of these aroma biosynthetic genes. Importantly, MabZIP4 directly binds to BanAAT promoter, while MabZIP5 binds to the promoters of MaMT1, MaACY1, MaAGT1, and BanAAT via the G-box motif, implicating the diverse functional significances of MabZIPs in controlling aroma biosynthesis in banana. Overall, this work sheds new insights on the understanding of transcriptional regulatory mechanisms associated with aroma formation during banana ripening.

Role of Circulating Fibrocytes in Cardiac Fibrosis.

OBJECTIVE: It is revealed that circulating fibrocytes are elevated in patients/animals with cardiac fibrosis, and this review aims to provide an introduction to circulating fibrocytes and their role in cardiac fibrosis. DATA SOURCES: This review is based on the data from 1994 to present obtained from PubMed. The search terms were "circulating fibrocytes " and "cardiac fibrosis ". STUDY SELECTION: Articles and critical reviews, which are related to circulating fibrocytes and cardiac fibrosis, were selected. RESULTS: Circulating fibrocytes, which are derived from hematopoietic stem cells, represent a subset of peripheral blood mononuclear cells exhibiting mixed morphological and molecular characteristics of hematopoietic and mesenchymal cells (CD34+/CD45+/collagen I+). They can produce extracellular matrix and many cytokines. It is shown that circulating fibrocytes participate in many fibrotic diseases, including cardiac fibrosis. Evidence accumulated in recent years shows that aging individuals and patients with hypertension, heart failure, coronary heart disease, and atrial fibrillation have more circulating fibrocytes in peripheral blood and/or heart tissue, and this elevation of circulating fibrocytes is correlated with the degree of fibrosis in the hearts. CONCLUSIONS: Circulating fibrocytes are effector cells in cardiac fibrosis.