98 research outputs found
Facile synthesis of carbon-11-labeled sEH/PDE4 dual inhibitors as new potential PET agents for imaging of sEH/PDE4 enzymes in neuroinflammation
To develop PET tracers for imaging of neuroinflammation, new carbon-11-labeled sEH/PDE4 dual inhibitors have been synthesized. The reference standard N-(4-methoxy-2-(trifluoromethyl)benzyl)benzamide (1) and its corresponding desmethylated precursor N-(4-hydroxy-2-(trifluoromethyl)benzyl)benzamide (2) were synthesized from (4-methoxy-2-(trifluoromethyl)phenyl)methanamine and benzoic acid in one and two steps with 84% and 49% overall chemical yield, respectively. The standard N-(4-methoxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide (MPPA, 4) and its precursor N-(4-hydroxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide (5) were synthesized from methyl 4-piperidinecarboxylate, propionyl chloride and (4-methoxy-2-(trifluoromethyl)phenyl)methanamine in two and three steps with 62% and 34% overall chemical yield, respectively. The target tracers N-(4-[11C]methoxy-2-(trifluoromethyl)benzyl)benzamide ([11C]1) and N-(4-[11C]methoxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide ([11C]MPPA, [11C]4) were prepared from their corresponding precursors 2 and 5 with [11C]CH3OTf through O-[11C]methylation and isolated by HPLC combined with SPE in 25–35% radiochemical yield, based on [11C]CO2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the molar activity (AM) at EOB was 370–740 GBq/μmol with a total synthesis time of 35–40-minutes from EOB
Valence band offset of InN/BaTiO3 heterojunction measured by X-ray photoelectron spectroscopy
X-ray photoelectron spectroscopy has been used to measure the valence band offset of the InN/BaTiO(3 )heterojunction. It is found that a type-I band alignment forms at the interface. The valence band offset (VBO) and conduction band offset (CBO) are determined to be 2.25 ± 0.09 and 0.15 ± 0.09 eV, respectively. The experimental VBO data is well consistent with the value that comes from transitivity rule. The accurate determination of VBO and CBO is important for use of semiconductor/ferrroelectric heterojunction multifunctional devices
Observation of a multitude of correlated states at the surface of bulk 1T-TaSe crystals
The interplay between electron-electron interactions and structural ordering
can yield exceptionally rich correlated electronic phases. We have used
scanning tunneling microscopy to investigate bulk 1T-TaSe2 and have uncovered
surprisingly diverse correlated surface states thereof. These surface states
exhibit the same in-plane charge density wave ordering but dramatically
different electronic ground states ranging from insulating to metallic. The
insulating variety of surface state shows signatures of a decoupled surface
Mott layer. The metallic surface states, on the other hand, exhibit zero-bias
peaks of varying strength that suggest Kondo phases arising from coupling
between the Mott surface layer and the metallic bulk of 1T-TaSe2. The surface
of bulk 1T-TaSe2 thus constitutes a rare realization of the periodic Anderson
model covering a wide parameter regime, thereby providing a model system for
accessing different correlated phenomena in the same crystal. Our results
highlight the central role played by strong correlations in this material
family
Molecular cloning and expression analysis of the MaASR1 gene in banana and functional characterization under salt stress
Background: Abscisic acid (ABA)-, stress- and ripening-induced protein
(ASR) is plant-specific hydrophilic transcriptional regulators involved
in sucrose stress and wounding in banana. However, it is not known
whether banana ASR genes confer salt stress tolerance. The contexts of
the studywas to analysis the sequence characterization of banana ASR1,
and identify its expression patterns and function under salt stress
using quantitative real-time PCR (qPCR) and overexpression in
Arabidopsis . The purpose was to evaluate the role of banana ASR1 to
salt stress tolerance employed by plants. Results: A full-length cDNA
isolated from banana fruitwas named MaASR1, and it had a 432 bp open
reading frame (ORF) encoding 143 amino acids. MaASR1 was preferential
expression in roots and leaves compared to low expression in fruits,
rhizomes and flowers. Under salt stress, the expression of MaASR1
quickly increased and highest expression level was detected in roots
and leaves at 4 h, and then gradually decreased. These results
suggested that MaASR1 expression was induced under salt stress. MaASR1
protein was localized in the nucleus and plasma membrane. MaASR1 was
transformed to Arabidopsis and verified by southern and northern
analysis, transgenic lines L14 and L38 integrated one and two copies of
MaASR1, respectively, while overexpression in transgenic lines provided
evidence for the role of MaASR1 to salt stress tolerance. Conclusions:
This study demonstrated that overexpression of MaASR1 in Arabidopsis
confers salt stress tolerance by reducing the expression of
ABA/stress-responsive genes, but does not affect the expression of the
ABA-independent pathway and biosynthesis pathway genes
Efficient regeneration and genetic transformation platform applicable to five Musa varieties
Background: Banana ( Musa spp.) is an important staple food, economic
crop, and nutritional fruit worldwide. Conventional breeding has been
seriously hampered by their long generation time, polyploidy, and
sterility of most cultivated varieties. Establishment of an efficient
regeneration and transformation system for banana is critical to its
genetic improvement and functional genomics. Results: In this study, a
vigorous and repeatable transformation systemfor banana using direct
organogenesiswas developed. The greatest number of shoots per explant
for all five Musa varieties was obtained using Murashige and Skoog
medium supplemented with 8.9 \u3bcM benzylaminopurine and 9.1 \u3bcM
thidiazuron. One immature male flower could regenerate 380\u2013456,
310\u2013372, 200\u2013240, 130\u2013156, and 100\u2013130
well-developed shoots in only 240\u2013270 d for Gongjiao, Red banana,
Rose banana, Baxi, and Xinglongnaijiao, respectively. Longitudinal
sections of buds were transformed through particle bombardment combined
with Agrobacterium -mediated transformation using a promoterless
\u3b2-glucuronidase (GUS) reporter gene; the highest transformation
efficiency was 9.81% in regenerated Gongjiao plantlets in an optimized
selection medium. Transgenic plants were confirmed by a histochemical
assay of GUS, polymerase chain reaction, and Southern blot.
Conclusions: Our robust transformation platform successfully generated
hundreds of transgenic plants. Such a platform will facilitate
molecular breeding and functional genomics of banana
Nicotine aggravates vascular adiponectin resistance via ubiquitin-mediated adiponectin receptor degradation in diabetic Apolipoprotein E knockout mouse
There is limited and discordant evidence on the role of nicotine in diabetic vascular disease. Exacerbated endothelial cell dysregulation in smokers with diabetes is associated with the disrupted adipose function. Adipokines possess vascular protective, anti-inflammatory, and anti-diabetic properties. However, whether and how nicotine primes and aggravates diabetic vascular disorders remain uncertain. In this study, we evaluated the alteration of adiponectin (APN) level in high-fat diet (HFD) mice with nicotine (NIC) administration. The vascular pathophysiological response was evaluated with vascular ring assay. Confocal and co-immunoprecipitation analysis were applied to identify the signal interaction and transduction. These results indicated that the circulating APN level in nicotine-administrated diabetic Apolipoprotein E-deficient (ApoE−/−) mice was elevated in advance of 2 weeks of diabetic ApoE−/− mice. NIC and NIC addition in HFD groups (NIC + HFD) reduced the vascular relaxation and signaling response to APN at 6 weeks. Mechanistically, APN receptor 1 (AdipoR1) level was decreased in NIC and further significantly reduced in NIC + HFD group at 6 weeks, while elevated suppressor of cytokine signaling 3 (SOCS3) expression was induced by NIC and further augmented in NIC + HFD group. Additionally, nicotine provoked SOCS3, degraded AdipoR1, and attenuated APN-activated ERK1/2 in the presence of high glucose and high lipid (HG/HL) in human umbilical vein endothelial cells (HUVECs). MG132 (proteasome inhibitor) administration manifested that AdipoR1 was ubiquitinated, while inhibited SOCS3 rescued the reduced AdipoR1. In summary, this study demonstrated for the first time that nicotine primed vascular APN resistance via SOCS3-mediated degradation of ubiquitinated AdipoR1, accelerating diabetic endothelial dysfunction. This discovery provides a potential therapeutic target for preventing nicotine-accelerated diabetic vascular dysfunction
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