Design of a high-bunch-charge 112-MHz superconducting RF photoemission electron source

High-bunch-charge photoemission electron-sources operating in a continuous wave (CW) mode are required for many advanced applications of particle accelerators, such as electron coolers for hadron beams, electron-ion colliders, and free-electron lasers. Superconducting RF (SRF) has several advantages over other electron-gun technologies in CW mode as it offers higher acceleration rate and potentially can generate higher bunch charges and average beam currents. A 112 MHz SRF electron photoinjector (gun) was developed at Brookhaven National Laboratory to produce high-brightness and high-bunch-charge bunches for the coherent electron cooling proof-of-principle experiment. The gun utilizes a quarter-wave resonator geometry for assuring beam dynamics and uses high quantum efficiency multi-alkali photocathodes for generating electrons.

Revenue management with two market segments and reserved capacity for priority customers

This paper studies a revenue management problem in which a finite number of substitutable commodities are sold to two different market segments at respective prices. It is required that a certain number of commodities are reserved for the high-price segment to ensure a minimum service level. The two segments are served concurrently at the beginning of the season. To improve revenues, management may choose to close the low-price segment at a time when the chance of selling all items at the high price is promising. The difficulty is determining when such a decision should be made. We derive the exact solution in closed form using the theory of optimal stopping time. We show that the optimal decision is made in reference to a sequence of thresholds in time. These time thresholds take both remaining sales season and inventory into account and exhibit a useful monotone property.

Enhanced antitumor effect of combining TRAIL and MnSOD mediated by CEA-controlled oncolytic adenovirus in lung cancer

Lung cancer, especially adenocarcinoma, is one of the leading causes of death in the world. Carcinoembryonic antigen (CEA), a superb non-small-cell lung cancer marker candidate, showed a beneficial effect in cancer therapy with oncolytic adenovirus in recent studies. Cancer-targeting dual gene-virotherapy delivers two therapeutic genes, linked by a connexon, in the replication-deficient vector instead of one gene so that they can work in common. In this study, we constructed a tumor-specific oncolytic adenovirus, CD55-TRAIL-IETD-MnSOD. The virus has the fusion protein complementary DNAs for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and for manganese superoxide dismutase (MnSOD) complementary DNA linked through a 4-amino acid caspase-8 cleavage site (IETD), and uses a CEA promoter to control virus E1A express. This is the first work to use a CEA promoter-regulated oncolytic adenovirus carrying two therapeutic genes for cancer research. Its targeting and anticancer capacity was evaluated by in vitro and in vivo experiments. The results indicated that CD55-TRAIL-IETD-MnSOD caused more cell apoptosis than CD55-TRAIL or CD55-MnSOD alone, or their combination in vitro, with low cytotoxicity of normal cells. In the A549 tumor xenograft model in nude mice, data showed that CD55-TRAIL-IETD-MnSOD could effectively suppress tumor growth than single gene groups, with no histological damage in liver, spleen or kidney tissues. Thus, the CEA-regulated dual-gene oncolytic virus CD55-TRAIL-IETD-MnSOD may be a novel potential therapy for lung cancer.

Total synthesis of mambalgin-1/2/3 by two-segment hydrazide-based native chemical ligation

Mambalgins are a class of 57-residue polypeptide toxins isolated from the venom of the African mamba. They exhibit potent analgesic effects by inhibiting the acid-sensing ion channels. Classified as members of the family of three-finger toxins, mambalgins contain four pairs of disulfide bridges that help to stabilize the three-finger scaffold. Here, we report the chemical synthesis of functional mambalgin-1/2/3 by using one-step two-segment hydrazide-based native chemical ligation. The two-segment ligation approach reported here may enable efficient production of mambalgin toxins. These synthetic mambalgins are useful compounds for development of diagnostic or therapeutic reagents. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Ion Permeation and Mechanotransduction Mechanisms of Mechanosensitive Piezo Channels

Piezo proteins have been proposed as the long-sought-after mechanosensitive cation channels in mammals that play critical roles in various mechanotransduction processes. However, the molecular bases that underlie their ion permeation and mechanotransduction have remained functionally undefined. Here we report our finding of the miniature pore-forming module of Piezo1 that resembles the pore architecture of other trimeric channels and encodes the essential pore properties. We further identified specific residues within the pore module that determine unitary conductance, pore blockage and ion selectivity for divalent and monovalent cations and anions. The non-pore-containing region of Piezo1 confers mechanosensitivity to mechano-insensitive trimeric acid-sensing ion channels, demonstrating that Piezo1 channels possess intrinsic mechanotransduction modules separate from their pore modules. In conclusion, this is the first report on the bona fide pore module and mechanotransduction components of Piezo channels, which define their ion-conducting properties and gating by mechanical stimuli, respectively.

Phonon optics, thermal expansion tensor, thermodynamic and chemical bonding properties of Al4SiC4 and Al4Si2C5: a first-principles study

The creation of stacking fault in Al₄SiC₄ crystal structure due to a phonon mode (E₁, 139.7 cm⁻¹, Raman active) at Γ-point with negative mode-Grüneisen constant (−0.28). (a) 3-D side-view; (b) 2-D side view.

MicroRNA-22 inhibits tumor growth and metastasis in gastric cancer by directly targeting MMP14 and Snail

MicroRNAs (miRNAs) deregulation is frequent in human gastric cancers (GCs), but the role of specific miRNAs involved in this disease remains elusive. MiR-22 was previously reported to act as tumor suppressors or oncogenes in diverse cancers. However, their accurate expression, function and mechanism in GC are largely unclear. Here, we found that the expression of miR-22 was significantly reduced in clinical GC tissues compared with paired adjacent normal tissues, and was significantly correlated with a more aggressive phenotype of GC in patients, and miR-22 low expression correlated with poor overall survival. The introduction of miR-22 markedly suppressed GC cell growth, migration and invasion, and inhibition of miR-22 promoted GC cell proliferation, migration and invasion in vitro. We further demonstrated that miR-22 acted as tumor suppressors through targeting extracellular matrix (ECM) remodeling member matrix metalloproteinase 14 (MMP14) and epithelial-to-mesenchymal transition (EMT) inducer Snail in GC. Moreover, ectopic expression of MMP14 or Snail restored inhibitory effects of miR-22 on cell migration and invasion in GC cells, and a negative relationship between the miR-22 expression and MMP14 or Snail mRNA levels was observed in GC. Finally, overexpression of miR-22 suppressed tumor growth, peritoneal dissemination and pulmonary metastasis in vivo. Taken together, we identified that miR-22 is a potent tumor suppressor in GC. MiR-22 downregulation promotes GC invasion and metastasis by upregulating MMP14 and Snail, and then inducing ECM remodeling and EMT. These findings provide a better understanding of the development and progression of GC and may be an important implication for future therapy of the GC.

Overexpression of miR-98 inhibits cell invasion in glioma cell lines via downregulation of IKKε

OBJECTIVE

MicroRNAs (miRNAs) function as negative regulators for the expression of genes involved in cancer metastasis. The aim of this study was to investigate the potential role of miR-98 in gliomas and validate its regulatory mechanism.

PATIENTS AND METHODS

Cell viability assays are used to measure proliferation of cell. mRNA expression is measured by qRT-PCR. Western blot analysis is used to measure protein expression.

RESULTS

Functional studies showed that miR-98 overexpression inhibited glioma migration and invasion, but had no effect on the cell viability. An enhanced green fluorescent protein reporter assay, quantitative RT-PCR, and a western blot analysis confirmed that miR-98 suppressed the expression of IκB kinase (IKKε) by directly targeting its 3'-untranslated region, also, the NF-κB p65 nuclear translocation and matrix metalloproteinase (MMP)-9 expression were significantly arrested in glioma cells treated with miR-98 mimics. Accordingly, the overexpression of IKKε or NF-κB p65 can restore cell migration and invasion after being inhibited by miR-98, and can restore NF-κB p65 nuclear translocation as well as increase MMP-9 expression.

CONCLUSIONS

These findings demonstrated that miR-98 functions as a tumor suppressor in gliomas. Furthermore, miR-98 may act as a potential therapeutic biomarker for glioma patients.

Local cytotoxic T-lymphocyte-associated antigen-4 immunoglobulin inhibition of rejection response is dependent on indoleamine 2,3-dioxygenase activities in the allograft

A previous study showed that local gene transfer of cytotoxic T-lymphocyte-associated antigen-4 immunoglobulin (CTLA4Ig) significantly prolonged the survival time of rat flap allografts. However, the underlying mechanism is not fully understood. Indoleamine 2,3-dioxygenase (IDO) is considered to be able to modulate the unresponsiveness state of allografts. In this study, we tested the expression of the CD80 molecule, IDO mRNA, and the level of the tryptophan metabolite kynurenine with or without the application of the IDO blocker 1-methyl-tryptophan (1-MT) in a rat composite tissue allotransplantation model. CD80 expression could be detected in the allograft. The ration of IDO mRNA/glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA and the level of kynurenine were both enhanced (46.3 ± 8.8 versus 4.6 ± 1.8 and 18.9 ± 1.3 μmol/L versus 2.1 ± 0.2 μmol/L separately) after adenovirus-mediated CTLA4Ig (AdCTLA4Ig) transduction. When 1-MT was applied to the AdCTLA4Ig perfusion recipients, the ration of IDO mRNA/GAPDH mRNA (5.2 ± 2.9) and the level of kynurenine (0.8 ± 0.5 μmol/L) were significantly reduced. Moreover, the allograft survival time was greatly reduced when 1-MT was applied to AdCTLA4Ig perfusion recipients compared to single AdCTLA4Ig perfusion therapy recipients (7.2 days versus 13.6 days). We showed that the inhibitory effect of locally delivered CTLA4Ig is dependent on IDO activities within the allograft.

Puerarin protects against damage to spatial learning and memory ability in mice with chronic alcohol poisoning

We evaluated the effect of puerarin on spatial learning and memory ability of mice with chronic alcohol poisoning. A total of 30 male C57BL/6 mice were randomly divided into model, puerarin, and control groups (n=10 each). The model group received 60% (v/v) ethanol by intragastric administration followed by intraperitoneal injection of normal saline 30 min later. The puerarin group received intragastric 60% ethanol followed by intraperitoneal puerarin 30 min later, and the control group received intragastric saline followed by intraperitoneal saline. Six weeks after treatment, the Morris water maze and Tru Scan behavioral tests and immunofluorescence staining of cerebral cortex and hippocampal neurons (by Neu-N) and microglia (by Ib1) were conducted. Glutamic acid (Glu) and gamma amino butyric acid (GABA) in the cortex and hippocampus were assayed by high-performance liquid chromatography (HPLC), and tumor necrosis factor (TNF)-α and interleukin (IL)-1β were determined by ELISA. Compared with mice in the control group, escape latency and distance were prolonged, and spontaneous movement distance was shortened (P<0.05) by puerarin. The number of microglia was increased in both the cortex and hippocampal dentate gyrus (P<0.01), and neurons were reduced only in the hippocampal dentate gyrus (P<0.01) in puerarin-treated mice. In the model group, Glu and GABA levels decreased (P<0.05), and Glu/GABA, TNF-α, and IL-1β increased (P<0.01) with puerarin treatment, returning to near normal levels. In conclusion, puerarin protected against the effects of chronic alcohol poisoning on spatial learning and memory ability primarily because of anti-inflammatory activity and regulation of the balance of Glu and GABA.

MicroRNA-141 inhibits tumor growth and metastasis in gastric cancer by directly targeting transcriptional co-activator with PDZ-binding motif, TAZ

Gastric cancer (GC) is a biologically heterogeneous disease accompanying various genetic and epigenetic alterations, and the molecular mechanisms underlying this disease are complex and not completely understood. Increasing evidence shows that abnormal microRNA (miRNA) expression is involved in GC tumorigenesis, but the role of specific miRNAs involved in this disease remains elusive. MiR-141 was previously reported to act as tumor suppressors or oncogenes in diverse cancers. However, their accurate expression, function and mechanism in GC are largely unclear. Here we found that the expression of miR-141 was significantly reduced in GC compared with paired adjacent normal tissues and was significantly correlated with a more aggressive phenotype of GC in patients. Ectopic expression of miR-141 mimics in GC cell lines resulted in reduced proliferation, invasion and migration, and inhibition of miR-141 in GC cell lines promoted cell proliferation, invasion and migration in vitro. We further demonstrated that miR-141 acted as tumor suppressors through targeting transcriptional co-activator with PDZ-binding motif (TAZ) in GC. Moreover, the inverse relationship between miR-141 and its target was verified in patients and xenograft mice. Finally, overexpression of miR-141 suppressed tumor growth and pulmonary metastasis in nude mice. Take together, we identified that miR-141 is a potent tumor suppressor in the stomach, and its growth inhibitory effects are, in part, mediated through its downstream target gene, TAZ. These findings implied that miR-141 might be employed as novel prognostic markers and therapeutic targets of GC.

MicroRNA-25 promotes gastric cancer migration, invasion and proliferation by directly targeting transducer of ERBB2, 1 and correlates with poor survival

Gastric cancer (GC) is one of the most common tumors and the molecular mechanism underlying its metastasis is still largely unclear. Here, we show that miR-25 was overexpressed in plasma and primary tumor tissues of GC patients with tumor node metastasis stage (III or IV) or lymph node metastasis. MiR-25 inhibition significantly decreased the metastasis, invasion and proliferation of GC cells in vitro, and reduced their capacity to develop distal pulmonary metastases and peritoneal dissemination in vivo. Furthermore, miR-25 repressed transducer of ERBB2, 1 (TOB1) expression by directly binding to TOB1-3'-UTR, and the inverse correlation was observed between the expressions of miR-25 and TOB1 mRNA in primary GC tissues. Moreover, the loss of TOB1 increased the metastasis, invasion and proliferation of GC cells, and the restoration of TOB1 led to suppressed metastasis, invasion and proliferation. The receiver operating characteristics analysis yielded an area under the curve value of 0.7325 in distinguishing the GC patients with death from those with survival. The analysis of optimal cutoff value revealed poor survival in GC patients with high plasma concentrations of miR-25 (>0.2333 amol/μl). Taken together, miR-25 promotes GC progression by directly downregulating TOB1 expression, and may be a noninvasive biomarker for the prognosis of GC patients.

Three-dimensional visualization of rat brain microvasculature following permanent focal ischaemia by synchrotron radiation

OBJECTIVE

Identifying morphological changes that occur in microvessels under both normal and ischaemic conditions is crucial for understanding and treating stroke. However, conventional imaging techniques are not able to detect microvessels on a micron or sub-micron scale without angiography. In the present study, synchrotron radiation (SR)-based X-ray in-line phase contrast imaging (ILPCI) was used to acquire high-resolution and high-contrast images of rat brain tissues in both normal and ischaemic states.

METHODS

ILPCI was performed at the Shanghai Synchrotron Radiation Facility, Shanghai, China, without the use of contrast agents. CT slices were reformatted and then converted into three-dimensional (3D) reconstruction images to analyse subtle details of the cerebral microvascular network.

RESULTS

By using ILPCI, brain vessels up to 11.8 μm in diameter were resolved. The number of cortical and penetrating arteries detected were found to undergo a remarkable decrease within the infarct area. 3 days after permanent ischaemia, vascular masses were also observed in the peripheral region of the infarcts.

CONCLUSION

SR-based ILPCI-CT can serve as a powerful tool to accurately visualize brain microvasculature. The morphological parameters of blood vessels in both CT slices and 3D reconstructions were determined, and this approach has great potential for providing an effective diagnosis and evaluation for rehabilitation therapy for stroke.

ADVANCES IN KNOWLEDGE

In the absence of contrast agent, the 3D morphologies of the brain microvasculature in normal and stroke rats were obtained using SR-based ILPCI. SR imaging is a sensitive and promising method which can be used to explore primary brain function.

Proteomic analysis of nuclei dissected from fixed rat brain tissue using expression microdissection

Expression microdissection (xMD) is a high-throughput, operator-independent technology that enables the procurement of specific cell populations from tissue specimens. In this method, histological sections are first stained for cellular markers via either chemical or immuno-guided methods, placed in close contact with an ethylene vinyl acetate (EVA) film, and exposed to a light source. The focal, transient heating of the stained cells or subcellular structures melts the EVA film selectively to the targets for procurement. In this report, we introduce a custom-designed flashcube system that permits consistent and reproducible microdissection of nuclei across an FFPE rat brain tissue section in milliseconds. In addition, we present a method to efficiently recover and combine captured proteins from multiple xMD films. Both light and scanning electron microscopy demonstrated captured nuclear structures. Shotgun proteomic analysis of the samples showed a significant enrichment in nuclear localized proteins, with an average 25% of recovered proteins localized to the nucleus, versus 15% for whole tissue controls (p < 0.001). Targeted mass spectrometry using multiple reaction monitoring (MRM) showed more impressive data, with a 3-fold enrichment in histones, and a concurrent depletion of proteins localized to the cytoplasm, cytoskeleton, and mitochondria. These data demonstrate that the flashcube-xMD technology is applicable to the proteomic study of a broad range of targets in molecular pathology.

Inverted Duplication and Deletion of 10q25q26 in a Patient without Any Obvious Skeletal Anomalies

We report on a girl with inverted duplication and deletion of 10q25q26 revealed by array-CGH and FISH analysis. Array-CGH analysis demonstrated a ∼13.1-Mb duplication encompassing 10q25.3q26.2 and a ∼5-Mb deletion at 10q26.2q26.3. No single-copy region was detected between the deleted and duplicated segments. FISH analysis found the arrangement duplicated in an inverted position. FISH analysis using the same probes did not show any abnormality in both parents, which indicates a de novo occurrence. The frequently reported features of distal 10q duplication include developmental delay, blepharophimosis, hypotonia, skeletal anomalies and some facial dysmorphisms. The girl presented with many features of distal 10q duplication with the exception of skeletal anomalies. To our knowledge, this is the fourth patient reported in the literature with inv dup del 10q. 10q duplication seems to account for most of the phenotypes for our patient. Although no obvious skeletal feature was found in our patient at present, follow-up assessment of skeletal development should be planned with the increase of age.

Association study of myelin transcription factor 1-like polymorphisms with schizophrenia in Han Chinese population

Schizophrenia (SZ) is characterized by a variety of complex positive, negative and cognitive symptoms that are differentially expressed in individual patients. Variability in symptom presentation indicates that multiple genes, many involved in neurodevelopment, contribute to the etiology of SZ. The myelin transcription factor 1-like (MYT1L) gene encodes the MYT1L protein that participates in several neurodevelopment pathways. The copy number variant of MYT1L gene is associated with SZ, and single-nucleotide polymorphisms (SNPs) of MYT1L contribute to major depressive disorder. To explore the association of MYT1L polymorphisms with SZ, we examined six SNPs of MYT1L in a Han Chinese population consisting of 528 paranoid schizophrenic patients and 528 healthy subjects. Our results showed that rs17039584 was significantly associated with SZ (A>G), even after Bonferroni correction. When subjects were divided by gender, the rs10190125 allele and genotype remained significantly associated with SZ in female patients. Moreover, we found that rs6742365 was associated with a family history of SZ in females. Other SNPs did not achieve statistical significance for SZ but were associated with individual phenotypes, as measured by the Positive and Negative Syndrome Scale (PANSS) inventory. Our findings suggest that MYT1L may represent a susceptibility gene for SZ in the Han Chinese population and show that a specific SNP may increase susceptibility in females.

Experimental study on air-stream gasification of biomass micron fuel (BMF) in a cyclone gasifier

Based on biomass micron fuel (BMF) with particle size of less than 250 microm, a cyclone gasifier concept has been considered in our laboratory for biomass gasification. The concept combines and integrates partial oxidation, fast pyrolysis, gasification, and tar cracking, as well as a shift reaction, with the purpose of producing a high quality of gas. In this paper, experiments of BMF air-stream gasification were carried out by the gasifier, with energy for BMF gasification produced by partial combustion of BMF within the gasifier using a hypostoichiometric amount of air. The effects of ER (0.22-0.37) and S/B (0.15-0.59) and biomass particle size on the performances of BMF gasification and the gasification temperature were studied. Under the experimental conditions, the temperature, gas yields, LHV of the gas fuel, carbon conversion efficiency, stream decomposition and gasification efficiency varied in the range of 586-845 degrees C, 1.42-2.21 N m(3)/kg biomass, 3806-4921 kJ/m(3), 54.44%-85.45%, 37.98%-70.72%, and 36.35%-56.55%, respectively. The experimental results showed that the gasification performance was best with ER being 3.7 and S/B being 0.31 and smaller particle, as well as H(2)-content. And the BMF gasification by air and low temperature stream in the cyclone gasifier with the energy self-sufficiency is reliable.

Correction of congenital severe ptosis by suspension of a frontal muscle flap overlapped with an inferiorly based orbital septum flap

BACKGROUND

This report introduces a new method for correction of congenital severe upper eyelid ptosis.

METHODS

The poor levator-function upper eyelid ptosis of 22 patients was corrected using suspension of the frontal muscle flap overlapped with an inferiorly based orbital septum flap as a motor unit, which substituted for the function of the levator muscle. The frontal muscle flap and orbital septum flap were formed in the frontal part and upper eyelid, respectively. Two flaps were overlapped and sutured to suspend the upper eyelid and to correct the congenital severe upper eyelid ptosis. This technique avoids the need for the linking structure necessary with the standard frontalis sling approach and improves the direction of pull to mimic that of a normal levator more closely than that of frontalis muscle advancement.

RESULTS

The follow-up period ranged from 6 to 20 months (mean, 12 months). A total of 4 patients had bilateral surgery, whereas 18 patients underwent unilateral surgery (26 eyelids). In 22 cases (26 eyes), congenital severe upper eyelid ptosis was treated using suspension of the frontal muscle flap overlapped with an inferiorly based orbital septum flap. After the operation, 17 cases (19 eyes) were followed up and analyzed retrospectively. The average follow-up period was about 12 months (range, 6-20 months). The 17 corrected eyes had a symmetric redundant fold of preseptal skin according to the marginal reflex distance-1 (MRD-1) measurement used to judge efficacy. Two eyes in this series required reoperation for undercorrection. Complications such as ectropion and corneal exposure were avoided.

CONCLUSION

Use of a frontalis muscle lap overlapped with an inferior based orbital septum flap to manage severe congenital upper eyelid ptosis is a useful procedure that results in substantial cosmetic and functional improvement with few complications.

Functional consequence of protein kinase A-dependent phosphorylation of the cardiac ryanodine receptor: sensitization of store overload-induced Ca2+ release

The phosphorylation of the cardiac Ca(2+)-release channel (ryanodine receptor, RyR2) by protein kinase A (PKA) has been extensively characterized, but its functional consequence remains poorly defined and controversial. We have previously shown that RyR2 is phosphorylated by PKA at two major sites, serine 2,030 and serine 2,808, of which Ser-2,030 is the major PKA site responding to beta-adrenergic stimulation. Here we investigated the effect of the phosphorylation of RyR2 by PKA on the properties of single channels and on spontaneous Ca(2+) release during sarcoplasmic reticulum Ca(2+) overload, a process we have referred to as store overload-induced Ca(2+) release (SOICR). We found that PKA activated single RyR2 channels in the presence, but not in the absence, of luminal Ca(2+). On the other hand, PKA had no marked effect on the sensitivity of the RyR2 channel to activation by cytosolic Ca(2+). Importantly, the S2030A mutation, but not mutations of Ser-2,808, diminished the effect of PKA on RyR2. Furthermore, a phosphomimetic mutation, S2030D, potentiated the response of RyR2 to luminal Ca(2+) and enhanced the propensity for SOICR in HEK293 cells. In intact rat ventricular myocytes, the activation of PKA by isoproterenol reduced the amplitude and increased the frequency of SOICR. Confocal line-scanning fluorescence microscopy further revealed that the activation of PKA by isoproterenol increased the rate of Ca(2+) release and the propagation velocity of spontaneous Ca(2+) waves, despite reduced wave amplitude and resting cytosolic Ca(2+). Collectively, our data indicate that PKA-dependent phosphorylation enhances the response of RyR2 to luminal Ca(2+) and reduces the threshold for SOICR and that this effect of PKA is largely mediated by phosphorylation at Ser-2,030.

Three-dimensional localization of serine 2808, a phosphorylation site in cardiac ryanodine receptor

Type 2 ryanodine receptor (RyR2) is the major calcium release channel in cardiac muscle. Phosphorylation of RyR2 by cAMP-dependent protein kinase A and by calmodulin-dependent protein kinase II modulates channel activity. Hyperphosphorylation at a single amino acid residue, Ser-2808, has been proposed to directly disrupt the binding of a 12.6-kDa FK506-binding protein (FKBP12.6) to RyR2, causing a RyR2 malfunction that triggers cardiac arrhythmias in human heart failure. To determine the structural basis of the interaction between Ser-2808 and FKBP12.6, we have employed two independent approaches to map this phosphorylation site in RyR2 by three-dimensional cryo-electron microscopy. In one approach, we inserted a green fluorescent protein (GFP) after amino acid Tyr-2801, and mapped the GFP three-dimensional location in the RyR2 structure. In another approach, the binding site of monoclonal antibody 34C was mapped in the three-dimensional structure of skeletal muscle RyR1. The epitope of antibody 34C has been mapped to amino acid residues 2,756 through 2,803 of the RyR1 sequence, corresponding to residues 2,722 through 2,769 of the RyR2 sequence. These locations of GFP insertion and antibody binding are adjacent to one another in domain 6 of the cytoplasmic clamp region. Importantly, the three-dimensional location of the Ser-2808 phosphorylation site is 105-120 A distance from the FKBP12.6 binding site mapped previously, indicating that Ser-2808 is unlikely to be directly involved in the binding of FKBP12.6 to RyR2, as had been proposed previously.

Ca 2+ /Calmodulin Kinase II-Dependent Phosphorylation of Ryanodine Receptors Suppresses Ca 2+ Sparks and Ca 2+ Waves in Cardiac Myocytes

The multifunctional Ca 2+ /calmodulin-dependent protein kinase II δ C (CaMKIIδ C ) is found in the macromolecular complex of type 2 ryanodine receptor (RyR2) Ca 2+ release channels in the heart. However, the functional role of CaMKII-dependent phosphorylation of RyR2 is highly controversial. To address this issue, we expressed wild-type, constitutively active, or dominant-negative CaMKIIδ C via adenoviral gene transfer in cultured adult rat ventricular myocytes. CaMKII-mediated phosphorylation of RyR2 was reduced, enhanced, or unaltered by dominant-negative, constitutively active, or wild-type CaMKIIδ C expression, whereas phosphorylation of phospholamban at Thr17, an endogenous indicator of CaMKII activity, was at 73%, 161%, or 115% of the control group expressing β-galactosidase (β-gal), respectively. In parallel with the phospholamban phosphorylation, the decay kinetics of global Ca 2+ transients was slowed, accelerated, or unchanged, whereas spontaneous Ca 2+ spark activity was hyperactive, depressed, or unchanged in dominant-negative, constitutively active, or wild-type CaMKIIδ C groups, respectively. When challenged by high extracellular Ca 2+ , both wild-type and constitutively active CaMKIIδ C protected the cells from store overload-induced Ca 2+ release, manifested by a ≈60% suppression of Ca 2+ waves (at 2 to 20 mmol/L extracellular Ca 2+ ) in spite of an elevated sarcoplasmic reticulum Ca 2+ content, whereas dominant-negative CaMKIIδ C promoted Ca 2+ wave production (at 20 mmol/L Ca 2+ ) with significantly depleted sarcoplasmic reticulum Ca 2+ . Taken together, our data support the notion that CaMKIIδ C negatively regulates RyR2 activity and spontaneous sarcoplasmic reticulum Ca 2+ release, thereby affording a negative feedback that stabilizes local and global Ca 2+ -induced Ca 2+ release in the heart.

Adsorption properties of HKUST-1 toward hydrogen and other small molecules monitored by IR

Among microporous systems metal organic frameworks are considered promising materials for molecular adsorption. In this contribution infrared spectroscopy is successfully applied to highlight the positive role played by coordinatively unsaturated Cu2+ ions in HKUST-1, acting as specific interaction sites. A properly activated material, obtained after solvent removal, is characterized by a high fraction of coordinatively unsaturated Cu2+ ions acting as preferential adsorption sites that show specific activities towards some of the most common gaseous species (NO, CO2, CO, N2 and H2). From a temperature dependent IR study, it has been estimated that the H2 adsorption energy is as high as 10 kJ mol(-1). A very complex spectral evolution has been observed upon lowering the temperature. A further peculiarity of this material is the fact that it promotes ortho-para conversion of the adsorbed H2 species.

Ser-2030, but not Ser-2808, is the major phosphorylation site in cardiac ryanodine receptors responding to protein kinase A activation upon beta-adrenergic stimulation in normal and failing hearts

We have recently shown that RyR2 (cardiac ryanodine receptor) is phosphorylated by PKA (protein kinase A/cAMP-dependent protein kinase) at two major sites, Ser-2030 and Ser-2808. In the present study, we examined the properties and physiological relevance of phosphorylation of these two sites. Using site- and phospho-specific antibodies, we demonstrated that Ser-2030 of both recombinant and native RyR2 from a number of species was phosphorylated by PKA, indicating that Ser-2030 is a highly conserved PKA site. Furthermore, we found that the phosphorylation of Ser-2030 responded to isoproterenol (isoprenaline) stimulation in rat cardiac myocytes in a concentration- and time-dependent manner, whereas Ser-2808 was already substantially phosphorylated before beta-adrenergic stimulation, and the extent of the increase in Ser-2808 phosphorylation after beta-adrenergic stimulation was much less than that for Ser-2030. Interestingly, the isoproterenol-induced phosphorylation of Ser-2030, but not of Ser-2808, was markedly inhibited by PKI, a specific inhibitor of PKA. The basal phosphorylation of Ser-2808 was also insensitive to PKA inhibition. Moreover, Ser-2808, but not Ser-2030, was stoichiometrically phosphorylated by PKG (protein kinase G). In addition, we found no significant phosphorylation of RyR2 at the Ser-2030 PKA site in failing rat hearts. Importantly, isoproterenol stimulation markedly increased the phosphorylation of Ser-2030, but not of Ser-2808, in failing rat hearts. Taken together, these observations indicate that Ser-2030, but not Ser-2808, is the major PKA phosphorylation site in RyR2 responding to PKA activation upon beta-adrenergic stimulation in both normal and failing hearts, and that RyR2 is not hyperphosphorylated by PKA in heart failure. Our results also suggest that phosphorylation of RyR2 at Ser-2030 may be an important event associated with altered Ca2+ handling and cardiac arrhythmia that is commonly observed in heart failure upon beta-adrenergic stimulation.

Inhibition of growth and increase of alkaline phosphatase activity in cultured human oral cancer cells by all-trans retinoic acid

In this study, the effects of all-trans retinoic acid (ATRA) on human oral cancer cells with regard to cell growth, the cell cycle, and alkaline phosphatase (ALP) activity were evaluated. Human oral cancer KB cells were treated with various concentrations of ATRA, and cell growth was then determined using the MTT viability assay. The cell-cycle distribution and ALP activity were analysed using a flow cytometer and chemical analyser, respectively. The KB cells were inhibited by ATRA at concentrations of 1-16 microM (1 microM, P<0.05; 2 microM, P<0.01; 4, 8 and 16 microM, P<0.001) in a dose-dependent manner. ATRA arrested KB cells in the G0/G1 phase. The ALP activity in KB cells was increased by ATRA. This is one of the first studies to focus on the expression of ALP in human head-and-neck carcinoma cells treated with retinoids. These findings suggest that the anti-tumour effects of ATRA on human oral cancer are associated with G0/G1 phase arrest and an increase in ALP activity.