ABSCISIC ACID-INSENSITIVE 5-KIP-RELATED PROTEIN 1-SHOOT MERISTEMLESS modulates reproductive development of Arabidopsis.

Soil (or plant) water deficit accelerates plant reproduction. However, the underpinning molecular mechanisms remain unknown. By modulating cell division/number, ABSCISIC ACID-INSENSITIVE 5 (ABI5), a key bZIP (basic (region) leucine zippers) transcription factor, regulates both seed development and abiotic stress responses. The KRP (KIP-RELATED PROTEIN) cyclin-dependent kinases (CDKs) play an essential role in controlling cell division, and SHOOT MERISTEMLESS (STM) plays a key role in the specification of flower meristem identity. Here, our findings show that abscisic acid (ABA) signaling and/or metabolism in adjust reproductive outputs (such as rosette leaf number and open flower number) under water-deficient conditions in Arabidopsis (Arabidopsis thaliana) plants. Reproductive outputs increased under water-sufficient conditions but decreased under water-deficient conditions in the ABA signaling/metabolism mutants abscisic acid2-1 (aba2-1), aba2-11, abscisic acid insensitive3-1 (abi3-1), abi4-1, abi5-7, and abi5-8. Further, under water-deficient conditions, ABA induced-ABI5 directly bound to the promoter of KRP1, which encodes a CDK that plays an essential role in controlling cell division, and this binding subsequently activated KRP1 expression. In turn, KRP1 physically interacted with SHOOT MERISTEMLESS (STM), which functions in the specification of flower meristem identity, promoting STM degradation. We further demonstrate that reproductive outputs are adjusted by the ABI5-KRP1-STM molecular module under water-deficient conditions. Together, our findings reveal the molecular mechanism by which ABA signaling and/or metabolism regulate reproductive development under water-deficient conditions. These findings provide insights that may help guide crop yield improvement under water deficiency.

Glucose status within dark-grown etiolated cotyledons determines seedling de-etiolation upon light irradiation.

Exposure of dark-grown etiolated seedlings to light triggers the transition from skotomorphogenesis/etiolation to photomorphogenesis/de-etiolation. In the life cycle of plants, de-etiolation is essential for seedling development and plant survival. The mobilization of soluble sugars (glucose [Glc], sucrose, and fructose) derived from stored carbohydrates and lipids to target organs, including cotyledons, hypocotyls, and radicles, underpins de-etiolation. Therefore, dynamic carbohydrate biochemistry is a key feature of this phase transition. However, the molecular mechanisms coordinating carbohydrate status with the cellular machinery orchestrating de-etiolation remain largely opaque. Here, we show that the Glc sensor HEXOKINASE 1 (HXK1) interacts with GROWTH REGULATOR FACTOR5 (GRF5), a transcriptional activator and key plant growth regulator, in Arabidopsis (Arabidopsis thaliana). Subsequently, GRF5 directly binds to the promoter of phytochrome A (phyA), encoding a far-red light (FR) sensor/cotyledon greening inhibitor. We demonstrate that the status of Glc within dark-grown etiolated cotyledons determines the de-etiolation of seedlings when exposed to light irradiation by the HXK1-GRF5-phyA molecular module. Thus, following seed germination, accumulating Glc within dark-grown etiolated cotyledons stimulates a HXK1-dependent increase of GRF5 and an associated decrease of phyA, triggering the perception, amplification, and relay of HXK1-dependent Glc signaling, thereby facilitating the de-etiolation of seedlings following light irradiation. Our findings, therefore, establish how cotyledon carbohydrate signaling under subterranean darkness is sensed, amplified, and relayed, determining the phase transition from skotomorphogenesis to photomorphogenesis on exposure to light irradiation.

Role of hydrogen sulphide in physiological and pathological angiogenesis.

The role of hydrogen sulphide (H2 S) in angiogenesis has been widely demonstrated. Vascular endothelial growth factor (VEGF) plays an important role in H2 S-induced angiogenesis. H2 S promotes angiogenesis by upregulating VEGF via pro-angiogenic signal transduction. The involved signalling pathways include the mitogen-activated protein kinase pathway, phosphoinositide-3 kinase pathway, nitric oxide (NO) synthase/NO pathway, signal transducer and activator of transcription 3 (STAT3) pathway, and adenosine triphosphate (ATP)-sensitive potassium (KATP ) channels. H2 S has been shown to contribute to tumour angiogenesis, diabetic wound healing, angiogenesis in cardiac and cerebral ischaemic tissues, and physiological angiogenesis during the menstrual cycle and pregnancy. Furthermore, H2 S can exert an anti-angiogenic effect by inactivating Wnt/ß-catenin signalling or blocking the STAT3 pathway in tumours. Therefore, H2 S plays a double-edged sword role in the process of angiogenesis. The regulation of H2 S production is a promising therapeutic approach for angiogenesis-associated diseases. Novel H2 S donors and/or inhibitors can be developed in the treatment of angiogenesis-dependent diseases.

SPECT myocardial perfusion versus fractional flow reserve for evaluation of functional ischemia: a meta analysis.

PURPOSE: The present meta-analysis illustrates the accuracy of myocardial perfusion SPECT (MPS) to diagnose functional stenotic coronary artery disease (CAD) with fractional flow reserve (FFR) as standard reference. METHODS: All investigators screened and selected studies that compared MPS with FFR in symptomatic patients with suspected CAD. Patients and study characteristics were independently extracted by two investigators; differences were resolved by consensus. RESULTS: 13 articles, including 1,017 patients, 699 vessels were included in the study. No significant publication bias was detected (P=0.65). At the patient level, the summary sensitivity and specificity were 77% (95% confidence interval [CI], 70-83%) and 77% (95%CI, 67-84%) for MPS. Vessel-level pooled sensitivity was 66% (95%CI, 57-74%) and specificity was 81% (95%CI, 70-89%). The overall diagnostic performance of MPS was moderate. [The area under the summary receiver operating characteristic (sROC) curve was 0.83]. No study influenced the pooled results larger than 0.03. CONCLUSIONS: The accuracy between FFR and MPS SPECT was moderate.

[Differential judgment of coronary stenosis by 320-slice dynamic volume computed tomography and coronary angiography].

OBJECTIVE: To compare the characteristics of lesions with consistent and inconsistent judgments of coronary stenosis on 320-slice dynamic volume computed tomography (DVCT) versus coronary angiography (CAG). METHODS: Ninety-two patients (265 lesions) with CAG and DVCT within 2 weeks from January 2011 to May 2012 were enrolled. According to the matching degree of stenotic judgment, all lesions were divided into consistent and inconsistent groups. The position of lesions, degree of bending, plaque morphology and calcification proportion were analyzed. RESULTS: There were 236 lesions in consistent group versus 29 lesions in inconsistent group.In inconsistent group, there were more left circumflex artery, distal, ostial and tortuous lesions than that in consistent group (P < 0.05). At the same time, the proportion of nubbly type plaque, calcified plaque, nubbly and nodular type calcification in the main plaque in inconsistent group was higher than those in consistent group (P < 0.05).Segmental coronary calcium score (250 ± 210 vs 82 ± 66, P < 0.05), number of calcifications and calcification proportion in main plaque (55% ± 28% vs 43% ± 30%, P < 0.05) in inconsistent group were higher than those in consistent group (P < 0.05). CONCLUSION: When coronary lesion occurs in ostial, distal or tortuous position or its main plaque is of nubbly type with a heavy calcification load, the judgment of stenosis by CTA and CAG is more likely to be inconsistent.