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author:("Yang, hailing")
1.  Over-expression of the Arabidopsis proton-pyrophosphatase AVP1 enhances transplant survival, root mass, and fruit development under limiting phosphorus conditions 
Journal of Experimental Botany  2014;65(12):3045-3053.
Phosphorus (P), an element required for plant growth, fruit set, fruit development, and fruit ripening, can be deficient or unavailable in agricultural soils. Previously, it was shown that over-expression of a proton-pyrophosphatase gene AVP1/AVP1D (AVP1DOX) in Arabidopsis, rice, and tomato resulted in the enhancement of root branching and overall mass with the result of increased mineral P acquisition. However, although AVP1 over-expression also increased shoot biomass in Arabidopsis, this effect was not observed in tomato under phosphate-sufficient conditions. AVP1DOX tomato plants exhibited increased rootward auxin transport and root acidification compared with control plants. AVP1DOX tomato plants were analysed in detail under limiting P conditions in greenhouse and field trials. AVP1DOX plants produced 25% (P=0.001) more marketable ripened fruit per plant under P-deficient conditions compared with the controls. Further, under low phosphate conditions, AVP1DOX plants displayed increased phosphate transport from leaf (source) to fruit (sink) compared to controls. AVP1DOX plants also showed an 11% increase in transplant survival (P<0.01) in both greenhouse and field trials compared with the control plants. These results suggest that selection of tomato cultivars for increased proton pyrophosphatase gene expression could be useful when selecting for cultivars to be grown on marginal soils.
PMCID: PMC4071825  PMID: 24723407
Fruit development; H+-pyrophosphatase; phosphorus; root development; tomato; transplant efficiency.
2.  Clinical implications of elevated serum soluble CD137 levels in patients with acute coronary syndrome 
Clinics  2013;68(2):193-198.
Atherosclerosis is a chronic inflammatory disease. Research has focused on identifying specific serum biomarkers to detect vulnerable plaques. These markers serve as diagnostic tools for acute coronary syndrome and assist in identifying high-risk patients. However, the existing data are limited and conflicting. This study tested the hypothesis that CD137 levels identify patients with acute coronary syndrome who are at a heightened risk for recurrent cardiac events.
The levels of soluble CD137 (sCD137) were measured using ELISA in 180 patients with acute coronary syndrome and 120 patients with acute chest pain. Platelet activation was assessed by flow cytometry. Receiver operating characteristic curve analysis was performed to evaluate the prognostic characteristics of sCD137.
The levels of sCD137 were elevated in 75 patients with acute coronary syndromes and 20 patients with acute chest pain (>35.0 ng/ml). In patients with acute coronary syndrome, elevated sCD137 levels (>35.0 ng/ml) indicated an increased risk for major adverse cardiovascular events (OR = 1.93, 95% CI: 1.39-2.54). Elevated serum levels of sCD137 and cTnT were correlated with a significantly increased risk of major adverse cardiovascular events in both groups after 30 days, six months and nine months of follow-up. The increased sCD137 levels were significantly correlated with the levels of troponin I (r = 0.4799, p<0.001). Importantly, 26 patients with normal cTnI levels had acute coronary syndrome. However, elevated sCD137 levels identified these patients as a being high-risk subgroup (OR = 2.14, 95% CI: 1.25-4.13).
Elevated sCD137 levels indicate an increased risk of cardiovascular events in patients with acute coronary syndrome. Soluble CD137 may be a useful prognostic marker or indicator for adverse events in patients with acute coronary syndrome.
PMCID: PMC3584275  PMID: 23525315
CD137; Acute Coronary Syndrome; Atherosclerosis
3.  A study of the distobuccal root canal orifice of the maxillary second molars in Chinese individuals evaluated by cone-beam computed tomography 
Journal of Applied Oral Science  2012;20(5):563-567.
As is commonly understood, the root canal morphology of the maxillary molars is usually complex and variable. It is sometimes difficult to detect the distobuccal root canal orifice of a maxillary second molar with root canal treatment. No literature related to the distobuccal root canals of the maxillary second molars has been published.
To investigate the position of the distobuccal root canal orifice of the maxillary second molars in a Chinese population using cone-beam computed tomography (CBCT).
Material and methods
In total, 816 maxillary second molars from 408 patients were selected from a Chinese population and scanned using CBCT. The following information was recorded: (1) the number of root canals per tooth, (2) the distance between the mesiobuccal and distobuccal root canal orifice (DM), (3) the distance between the palatal and distobuccal root canal orifice (DP), (4) the angle formed by the mesiobuccal, distobuccal and palatal root canal orifices (∠ PDM). DM, DP and ∠ PDM of the teeth with three or four root canals were analyzed and evaluated.
In total, 763 (93.51%) of 816 maxillary second molars had three or four root canals. The distance between the mesiobuccal and distobuccal orifice was 0.7 to 4.8 mm. 621 (81.39%) of 763 teeth were distributed within 1.5-3.0 mm. The distance between the palatal and distobuccal orifice ranged from 0.8 mm to 6.7 mm; 585 (76.67%) and were distributed within 3.0-5.0 mm. The angle (∠ PDM) ranged from 69. 4º to 174.7º in 708 samples (92.80%), the angle ranged from 90º to 140º.
The position of the distobuccal root canal orifice of the maxillary second molars with 3 or 4 root canals in a Chinese population was complex and variable. Clinicians should have a thorough knowledge of the anatomy of the maxillary second molars.
PMCID: PMC3881797  PMID: 23138744
Cone-beam computed tomography; Distobuccal root canal; Maxillary second molar; Root and canal anatomy
4.  phot1 Inhibition of ABCB19 Primes Lateral Auxin Fluxes in the Shoot Apex Required For Phototropism 
PLoS Biology  2011;9(6):e1001076.
It is well accepted that lateral redistribution of the phytohormone auxin underlies the bending of plant organs towards light. In monocots, photoreception occurs at the shoot tip above the region of differential growth. Despite more than a century of research, it is still unresolved how light regulates auxin distribution and where this occurs in dicots. Here, we establish a system in Arabidopsis thaliana to study hypocotyl phototropism in the absence of developmental events associated with seedling photomorphogenesis. We show that auxin redistribution to the epidermal sites of action occurs at and above the hypocotyl apex, not at the elongation zone. Within this region, we identify the auxin efflux transporter ATP-BINDING CASSETTE B19 (ABCB19) as a substrate target for the photoreceptor kinase PHOTOTROPIN 1 (phot1). Heterologous expression and physiological analyses indicate that phosphorylation of ABCB19 by phot1 inhibits its efflux activity, thereby increasing auxin levels in and above the hypocotyl apex to halt vertical growth and prime lateral fluxes that are subsequently channeled to the elongation zone by PIN-FORMED 3 (PIN3). Together, these results provide new insights into the roles of ABCB19 and PIN3 in establishing phototropic curvatures and demonstrate that the proximity of light perception and differential phototropic growth is conserved in angiosperms.
Author Summary
Plants depend on sunlight for photosynthesis and adapt their growth to optimize light capture. Phototropism, the reorientation of growth towards light, is one important adaptive response. Modern studies of phototropism began with experiments in monocotyledonous grasses by Charles Darwin and led ultimately to the discovery of the plant growth hormone auxin, establishing the concept that light perception at the shoot apex triggers differential bending in the tissues below. In the past two decades, molecular-genetic analysis in the model flowering plant Arabidopsis thaliana has identified the principle photoreceptor for phototropism, phot1, as well as the major auxin transporters. Despite extensive efforts, how the photoreceptor regulates auxin transport so as to establish differential growth is still poorly understood, as is whether this process is conserved between monocots and dicots. Here, we introduce a new approach to the study of Arabidopsis phototropism in the absence of developmental events associated with seedling photomorphogenesis. In doing so, we show that the proximity of light perception and differential growth is conserved between monocots and dicots: in both plant types, differential growth is a consequence of lateral auxin movements across the shoot apex. Moreover, we identify two auxin transporters, PIN3 and ABCB19, that contribute to these movements, the latter serving to prime lateral auxin fluxes in the shoot apex. ABCB19 function is regulated by phot1, identifying it as a substrate for this class of photoreceptor kinase.
PMCID: PMC3110179  PMID: 21666806
5.  Plant Lessons: Exploring ABCB Functionality Through Structural Modeling 
In contrast to mammalian ABCB1 proteins, narrow substrate specificity has been extensively documented for plant orthologs shown to catalyze the transport of the plant hormone, auxin. Using the crystal structures of the multidrug exporters Sav1866 and MmABCB1 as templates, we have developed structural models of plant ABCB proteins with a common architecture. Comparisons of these structures identified kingdom-specific candidate substrate-binding regions within the translocation chamber formed by the transmembrane domains of ABCBs from the model plant Arabidopsis. These results suggest an early evolutionary divergence of plant and mammalian ABCBs. Validation of these models becomes a priority for efforts to elucidate ABCB function and manipulate this class of transporters to enhance plant productivity and quality.
PMCID: PMC3355715  PMID: 22639627
ABCB exporter; ABCB importer; structural modeling; auxin; substrate docking
6.  Auxin Transporters—Why So Many? 
Interacting and coordinated auxin transporter actions in plants underlie a flexible network that mobilizes auxin in response to many developmental and environmental changes encountered by these sessile organisms. The independent but synergistic activity of individual transporters can be differentially regulated at various levels. This invests auxin transport mechanisms with robust functional redundancy and added auxin flow capacity when needed. An evolutionary perspective clarifies the roles of the different transporter groups in plant development. Mathematical and functional analysis of elements of auxin transport makes it possible to rationalize the relative contributions of members of the respective transporter classes to the localized auxin transport streams that then underlie both preprogrammed developmental changes and reactions to environmental stimuli.
By using multiple transporters for the hormone auxin, plants can generate distinct hormonal responses to different stimuli and sustain high levels of auxin flow when needed.
PMCID: PMC2829953  PMID: 20300209

Results 1-6 (6)