Influences of −482C&gt;T and 3238G&gt;C polymorphisms of the <Emphasis Type="Italic">Apolipoprotein C3</Emphasis> gene on prevalence of metabolic syndrome

Apolipoprotein C3 (ApoC3) plays a regulatory role in triglyceride (TG) metabolism. The higher level of TG can be a cause in pathogenesis of the vascular diseases or metabolic syndrome (MetS). In this study, we examined the associations of ApoC3 polymorphisms (?482C>T rs2854117 and 3238G>C rs5128) with Korean MetS patients. A total of 835 subjects were investigated, including 320 patients with MetS and 515 healthy subjects. The genotype analysis of the ApoC3 polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism methods. Of the two polymorphisms studied, we observed a significant difference in the ?482C>T polymorphism between the MetS and control groups. The TT genotype of the ?482C>T polymorphism was associated with increased risk for MetS, compared with the controls (OR 1.627, 95 % CI 1.075–2.463, P = 0.021). The association was female-specific. No associations were found for the risk of MetS in the 3238G>C polymorphism. Haplotypes composed of two polymorphisms, however, were associated with MetS susceptibility in only male group. The 3238G>C polymorphism was significantly associated with TG levels (P = 0.013). Our data suggest that the ApoC3 ?482C>T polymorphism is associated with increased MetS susceptibility in the Korean population.     

Polymorphisms of extrinsic death receptor apoptotic genes (FAS −670 G&gt;A,FASL −844 T&gt;C) in coronary artery disease

Apoptosis plays an important role in atherogenesis and rupture of vulnerable plaques in coronary artery disease. FAS and FAS ligand (FASL) induce apoptosis when FAS binds to FAS-L. However sFas blocks apoptosis by binding to FAS and FASL or sFasL. The present study is sought to examine the role of extrinsic apoptotic genes (FAS, FASL) polymorphism and serum levels of FAS, FASL in the pathogenesis and susceptibility to CAD in south Indian population. The study included 300 CAD patients and 300 healthy controls. Lipid profiles, sFas, sFasL were estimated by commercially available kits. FAS ?670 G>A, FASL ?844 T>C genotypes were analyzed by PCR–RFLP. Secondary structures of pre mRNA were analyzed by the Vienna RNA webserver and gene–gene and gene–environment interactions were determined by MDR analysis. Total cholesterol, triglyceride and LDL levels were significantly high in CAD patients compared to the controls. Molecular analysis revealed that the frequency of the AA genotype of FAS (54 % vs 27 %) and CC genotypes of FASL (10.3 % vs 1.3 %) were high in CAD patients compared to controls. Secondary structure analysis of FAS and FASL confirmed our molecular analysis. sFas levels were low while serum sFasL were high in CAD patients. MDR analysis revealed synergistic effects of gene polymorphisms and additive effects of epidemiological factors on risk of CAD. Polymorphisms of FAS (?670 G/A), FASL (?844 T/C) and their circulating levels play an important role in the pathology of CAD.     

Structures and stability of N<Subscript>13</Subscript><Superscript>+</Superscript> and N<Subscript>13</Subscript><Superscript>−</Superscript> clusters

The structures and stabilities of eleven N₁₃ ⁺ and N₁₃ ^– isomers have been investigated with second-order Møller–Plesset (MP2) and density functional theory (DFT) methods. Five N₁₃ ⁺ isomers and six N₁₃ ^– isomers are all reasonable local minima on their potential energy hypersurfaces. The most stable N₁₃ ⁺ cation is structure C-2 with C_2v symmetry, which contains a pentazole ring and two N₄ open chains. It is different from those of the N₇ ⁺ and N₉ ⁺ clusters, but similar to the N₁₁ ⁺ cluster. Meanwhile, the most stable N₁₃ ^– structure A-2 is composed of a pentazole ring and a six-membered ring connected by two nitrogen atoms. It is not only different from those of the N₇ ^– and N₉ ^– clusters, but also from the N₁₁ ^– cluster. The decomposition pathways of structures C-2 and A-2 were investigated at the B3LYP/(aug)-cc-pVDZ level. From the barrier heights of the structures C-2 and A-2 decomposition processes, it is suggested that C-2 is difficult to observe experimentally and A-2 may be observed as a short-lived species. Figure Optimized geometrical parameters of N₁₃ ⁺ isomer C-2      

Determination of the lifetime of D<Stack><Subscript>2</Subscript><Superscript>−</Superscript></Stack> and HD<Superscript>−</Superscript> ions

A method for determining the lifetime of unstable ions is described. The method is based on measuring the decrease in the ion beam current onto a fixed detector with increasing path length of the ion beam from the ion source to the detector. The measurements performed for D^? ₂ and HD^? molecular ions have shown that their lifetimes are 3.5 ± 0.1 and 4.4 ± 0.1 μs, respectively.     

Variability and directionality of temporal changes in δ<Superscript>13</Superscript>C and δ<Superscript>15</Superscript>N of aquatic invertebrate primary consumers

Seasonal oscillations in the carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope signatures of aquatic algae can cause seasonal enrichment–depletion cycles in the isotopic composition of planktonic invertebrates (e.g., copepods). Yet, there is growing evidence that seasonal enrichment–depletion cycles also occur in the isotope signatures of larger invertebrate consumers, taxa used to define reference points in isotope-based trophic models (e.g., trophic baselines). To evaluate the general assumption of temporal stability in non-zooplankton aquatic invertebrates, δ¹³C and δ¹⁵N time series data from the literature were analyzed for seasonality and the influence of biotic (feeding group) and abiotic (trophic state, climate regime) factors on isotope temporal patterns. The amplitude of δ¹³C and δ¹⁵N enrichment–depletion cycles was negatively related to body size, although all size-classes of invertebrates displayed a winter-to-summer enrichment in δ¹³C and depletion in δ¹⁵N. Among feeding groups, periphytic grazers were more variable and displayed larger temporal changes in δ¹³C than detritivores. For nitrogen, temporal variability and magnitude of directional change of δ¹⁵N was most strongly related to ecosystem trophic state (eutrophic > mesotrophic, oligotrophic). This study provides evidence of seasonality in the isotopic composition of aquatic invertebrates across very broad geographical and ecological gradients as well as identifying factors that are likely to modulate the strength and variability of seasonality. These results emphasize the need for researchers to recognize the likelihood of temporal changes in non-zooplankton aquatic invertebrate consumers at time scales relevant to seasonal studies and, if present, to account for temporal dynamics in isotope trophic models.     

Estimation of denitrification potential in a karst aquifer using the <Superscript>15</Superscript>N and <Superscript>18</Superscript>O isotopes of NO<Stack><Subscript>3</Subscript><Superscript>−</Superscript></Stack>

A confined aquifer in the Malm Karst of the Franconian Alb, South Germany was investigated in order to understand the role of the vadose zone in denitrifiaction processes. The concentrations of chemical tracers Sr²⁺ and Cl^– and concentrations of stable isotope ¹⁸O were measured in spring water and precipitation during storm events. Based on these measurements a conceptual model for runoff was constructed. The results indicate that pre-event water, already stored in the system at the beginning of the event, flows downslope on vertical and lateral preferential flow paths. Chemical tracers used in a mixing model for hydrograph separation have shown that the pre-event water contribution is up to 30%. Applying this information to a conceptual runoff generation model, the values of ¹⁵N and ¹⁸O in nitrate could be calculated. Field observations showed the occurence of significant microbial denitrification processes above the soil/bedrock interface before nitrate percolates through to the deeper horizon of the vadose zone. The source of nitrate could be determined and denitrification processes were calculated. Assuming that the nitrate reduction follows a Rayleigh process one could approximate a nitrate input concentration of about 170 mg/l and a residual nitrate concentration of only about 15%. The results of the chemical and isotopic tracers postulate fertilizers as nitrate source with some influence of atmospheric nitrate. The combined application of hydrograph separation and determination of isotope values in ¹⁵N and ¹⁸O of nitrate lead to an improved understanding of microbial processes (nitrification, denitrification) in dynamic systems.     

Density functional theory study of interactions between carbon monoxide and iron tetraaza macrocyclic complexes,FeTXTAA (X = −Cl, −OH, −OCH<Subscript>3</Subscript>, −NH<Subscript>2</Subscript>, and –NO<Subscript>2</Subscript>)

This work describes a DFT level theoretical quantum study using the B3LYP functional with the Lanl2TZ(f)/6-31G* basis set to calculate parameters including the bond distances and angles, electronic configurations, interaction energies, and vibrational frequencies of FeTClTAA (iron-tetrachloro-tetraaza[14]annulene), FeTOHTAA (iron-tetrahydroxy-tetraaza[14]annulene), FeTOCH₃TAA (iron- tetramethoxy-tetraaza[14]annulene), FeTNH₂TAA (iron-tetraamino-tetraaza[14]annulene), and FeTNO₂TAA (iron-tetranitro-tetraaza[14]annulene) complexes, as well as their different spin multiplicities. The calculations showed that the complexes were most stable in the triplet spin state (S?=?1), while, after interaction with carbon monoxide, the singlet state was most stable. The reactivity of the complexes was evaluated using HOMO–LUMO gap calculations. Parameter correlations were performed in order to identify the best complex for back bonding (3d _xzFe?→?2p _xC and 3d _yzFe?→?2p _zC) with carbon monoxide, and the degree of back bonding increased in the order: FeTNO₂TAA?<?FeTClTAA?<?FeTOHTAA?<?FeTOCH₃TAA?<?FeTNH₂TAA.     

<Superscript>2</Superscript>H–<Superscript>13</Superscript>C correlation solid-state NMR for investigating dynamics and water accessibilities of proteins and carbohydrates

Site-specific determination of molecular motion and water accessibility by indirect detection of ²H NMR spectra has advantages over dipolar-coupling based techniques due to the large quadrupolar couplings and the ensuing high angular resolution. Recently, a Rotor Echo Short Pulse IRrAdiaTION mediated cross polarization (^RESPIRATIONCP) technique was developed, which allowed efficient transfer of ²H magnetization to ¹³C at moderate ²H radiofrequency field strengths available on most commercial MAS probes. In this work, we investigate the ²H–¹³C magnetization transfer characteristics of one-bond perdeuterated CD _n spin systems and two-bond H/D exchanged C–(O)–D and C–(N)–D spin systems in carbohydrates and proteins. Our results show that multi-bond, broadband ²H–¹³C polarization transfer can be achieved using ²H radiofrequency fields of ~50 kHz, relatively short contact times of 1.3–1.7 ms, and with sufficiently high sensitivity to enable 2D ²H–¹³C correlation experiments with undistorted ²H spectra in the indirect dimension. To demonstrate the utility of this ²H–¹³C technique for studying molecular motion, we show ²H–¹³C correlation spectra of perdeuterated bacterial cellulose, whose surface glucan chains exhibit a motionally averaged C6 ²H quadrupolar coupling that indicates fast trans-gauche isomerization about the C5–C6 bond. In comparison, the interior chains in the microfibril core are fully immobilized. Application of the ²H–¹³C correlation experiment to H/D exchanged Arabidopsis primary cell walls show that the O–D quadrupolar spectra of the highest polysaccharide peaks can be fit to a two-component model, in which 74% of the spectral intensity, assigned to cellulose, has a near-rigid-limit coupling, while 26% of the intensity, assigned to matrix polysaccharides, has a weakened coupling of 50 kHz. The latter O–D quadrupolar order parameter of 0.22 is significantly smaller than previously reported C–D dipolar order parameters of 0.46–0.55 for pectins, suggesting that additional motions exist at the C–O bonds in the wall polysaccharides. ²H–¹³C polarization transfer profiles are also compared between statistically deuterated and H/D exchanged GB1.     

NO<Subscript>3</Subscript><Superscript>−</Superscript>-Driven SO<Subscript>4</Subscript><Superscript>2−</Superscript> Production in Freshwater Ecosystems: Implications for N and S Cycling

Massive anthropogenic acceleration of the global nitrogen (N) cycle has stimulated interest in understanding the fate of excess N loading to aquatic ecosystems. Nitrate (NO₃ ⁻) is traditionally thought to be removed mainly by microbial respiratory denitrification coupled to carbon (C) oxidation, or through biomass assimilation. Alternatively, chemolithoautotrophic bacterial metabolism may remove NO₃ ⁻ by coupling its reduction with the oxidation of sulfide to sulfate (SO₄ ²⁻). The NO₃ ⁻ may be reduced to N₂ or to NH₄ ⁺, a form of dissimilatory nitrate reduction to ammonium (DNRA). The objectives of this study were to investigate the importance of S oxidation as a NO₃ ⁻ removal process across diverse freshwater streams, lakes, and wetlands in southwestern Michigan (USA). Simultaneous NO₃ ⁻ removal and SO₄ ²⁻ production were observed in situ using modified “push-pull” methods in nine streams, nine wetlands, and three lakes. The measured SO₄ ²⁻ production can account for a significant fraction (25–40%) of the overall NO₃ ⁻ removal. Addition of ¹⁵NO₃ ⁻ and measurement of ¹⁵NH₄ ⁺ production using the push–pull method revealed that DNRA was a potentially important process of NO₃ ⁻ removal, particularly in wetland sediments. Enrichment cultures suggest that Thiomicrospira denitrificans may be one of the organisms responsible for this metabolism. These results indicate that NO₃ ⁻-driven SO₄ ²⁻ production could be widespread and biogeochemically important in freshwater sediments. Removal of NO₃ ⁻ by DNRA may not ameliorate problems such as eutrophication because the N remains bio-available. Additionally, if sulfur (S) pollution enhances NO₃ ⁻ removal in freshwaters, then controls on N processing in landscapes subject to S and N pollution are more complex than previously appreciated. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Functional blockade of α<Subscript>5</Subscript>β<Subscript>1</Subscript> integrin induces scattering and genomic landscape remodeling of hepatic progenitor cells

Background  

Cell scattering is a physiological process executed by stem and progenitor cells during embryonic liver development and postnatal organ regeneration. Here, we investigated the genomic events occurring during this process induced by functional blockade of α₅β₁ integrin in liver progenitor cells.     

Comparisons of δ<Superscript>13</Superscript>C of photosynthetic products and ecosystem respiratory CO<Subscript>2</Subscript> and their responses to seasonal climate variability

This study investigated the relationship between ¹³C of ecosystem components, soluble plant carbohydrates and the isotopic signature of ecosystem respired CO₂ (¹³C_R) during seasonal changes in soil and atmospheric moisture in a beech (Fagus sylvatica L.) forest in the central Apennine mountains, Italy. Decrease in soil moisture and increase in air vapour pressure deficit during summer correlated with substantial increase in ¹³C of leaf and phloem sap soluble sugars. Increases in ¹³C of ecosystem respired CO₂ were linearly related to increases in phloem sugar ¹³C (r²=0.99, P0.001) and leaf sugar ¹³C (r²=0.981, P0.01), indicating that a major proportion of ecosystem respired CO₂ was derived from recent assimilates. The slopes of the best-fit lines differed significantly (P0.05), however, and were about 0.86 (SE=0.04) for phloem sugars and about 1.63 (SE=0.16) for leaf sugars. Hence, changes in isotopic signature in phloem sugars were transferred to ecosystem respiration in the beech forest, while leaf sugars, with relatively small seasonal changes in ¹³C, must have a slower turnover rate or a significant storage component. No significant variation in ¹³C was observed in bulk dry matter of various plant and ecosystem components (including leaves, bark, wood, litter and soil organics). The apparent coupling between the ¹³C of soluble sugars and ecosystem respiration was associated with large apparent isotopic disequilibria. Values of ¹³C_R were consistently more depleted by about 4 relative to phloem sugars, and by about 2 compared to leaf sugars. Since no combination of the measured pools could produce the observed ¹³C_R signal over the entire season, a significant isotopic discrimination against ¹³C might be associated with short-term ecosystem respiration. However, these differences might also be explained by substantial contributions of other not measured carbon pools (e.g., lipids) to ecosystem respiration or contributions linked to differences in footprint area between Keeling plots and carbohydrate sampling. Linking the seasonal and inter-annual variations in carbon isotope composition of carbohydrates and respiratory CO₂ should be applicable in carbon cycle models and help the understanding of inter-annual variation in biospheric sink strength.     

Effects of activation of μ-, κ<Subscript>1</Subscript>-, δ<Subscript>1</Subscript>-, δ<Subscript>2</Subscript>-, and ORL<Subscript>1</Subscript>-receptors on heart resistance to the pathogenic action of delayed ischemia and reperfusion

Different subtypes of opioid receptors (OR) were activated in rats in vivo to study the activation effect on the heart’s resistance to ischemia and reperfusion. It has been established that administration of deltorphin II, a selective δ₂-OR agonist, lowered the infarct size/area at risk index (IS/AAR) by 23%. Naltrexone, naloxone methiodide (an OR inhibitor not penetrating the blood-brain barrier (BBB)), and naltriben (δ₂-antagonist) eliminated the cardioprotective effect of deltorphin II, while BNTX (a δ₁-antagonist) produced no effect on the cardioprotective action of the δ₂-agonist. The infarct-reducing effect of deltorphin II was eliminated by administration of chelerythrine (a protein kinase C (PKC) inhibitor), glibenclamide (a K_ATP-channels inhibitor), and 5-hydroxydecanoate (a mitochondrial K_ATP-channel blocker). Administration of other opioids did not reduce the IS/AAR index. It has been established that all the deltorphins manifest antiarrhythmic potency. Other opioids do not produce any effect on the incidence of arrhythmia occurrences. The antiarrhythmic effect of deltorphin II was eliminated by preliminary administration of naltrexone, naloxone methiodide, and naltriben, but BNTX did not affect the δ₂-agonist’s anti-arrhythmic effect. The preliminary administration of chelerythrine, a PKC inhibitor, eliminated the δ₂ agonist’s antiarrhythmic action. However, glibenclamide and 5-hydroxydecanoate did not alter the antiarrhythmic effect by deltorphin II. Therefore, activation of the peripheral δ₂-ORs reduces the infarct size and prevents the onset of arrhythmias. The antiarrhythmic effect of the δ₂-OR stimulation is mediated by activating PKC and opening the mitochondrial K_ATP-channels. PKC participates in the antiarrhythmic effect of the δ₂-OR activation, but this effect does not depend on the condition of K_ATP-channels.     

Kinetic analysis of recombinant mammalian α<Subscript>1</Subscript> and α<Subscript>1</Subscript>β glycine receptor channels

To analyze the influence of the beta-subunit on the kinetic properties of GlyR channel currents, alpha(1)-subunits and alpha(1)beta-subunits were transiently expressed in HEK 293 cells. A piezo dimorph was used for fast application of glycine to outside-out patches. The rise time of activation was dose dependent for both receptors and decreased with increasing glycine concentrations. Subunit composition had no effect on the time course of activation. Coexpression of alpha(1)- and beta-subunits resulted in a significantly lower EC(50) and a reduced slope of the dose-response curve of glycine compared with expression of alpha(1)-subunits alone. For both receptor subtypes, the time course of desensitization was concentration dependent. Desensitization was best fitted with a single time constant at 10-30 micro M, with two at 0.1 mM, and at saturating concentrations (0.3-3 mM) with three time constants. Desensitization of homomeric alpha(1)-receptor channels was significantly slower than that of alpha(1)beta-receptor channels. The time course of current decay after the end of glycine pulses was tested at different pulse durations of 1 mM glycine. It was best fitted with two time constants for both alpha(1) and alpha(1)beta GlyR channels, and increased significantly with increasing pulse duration.     

Sequence specific <Superscript>1</Superscript>H, <Superscript>13</Superscript>C and <Superscript>15</Superscript>N resonance assignments of a cataract-related variant G57W of human γS-crystallin

γS-crystallin is a major structural component of the human eye lens, which maintains its stability over the lifetime of an organism with negligible turnover. The G57W mutant of human γS-crystallin (abbreviated hereafter as γS-G57W) is associated with dominant congenital cataracts. In order to provide a structural basis for the ability of γS-G57W causing cataract, we have cloned, overexpressed, isolated and purified the protein. The 2D [¹⁵N–¹H]-HSQC spectrum recorded with uniformly ¹³C/¹⁵N-labelled γS-G57W was highly dispersed indicating the protein to adopt an ordered conformation. In this paper, we report almost complete sequence-specific ¹H, ¹³C and ¹⁵N resonance assignments of γS-G57W using a suite of heteronuclear 3D NMR experiments.     

Study of Electric Explosion of Flat Micron-Thick Foils at Current Densities of (5−50)×10<Superscript>8</Superscript> A/cm<Superscript>2</Superscript>

Electric explosions of flat Al, Тi, Ni, Cu, and Та foils with thicknesses of 1?16 μm, widths of 1?8 mm, and lengths of 5?11 mm were studied experimentally on the BIN, XP, and COBRA high-current generators at currents of 40?1000 kA and current densities of (5–50) × 10⁸ A/cm². The images of the exploded foils were taken at different angles to the foil surface by using point projection radiography with an X-pinch hot spot as the radiation source, the spatial resolution and exposure time being 3 μm and 50 ps, respectively, as well by the laser probing method with a spatial resolution of 20 μm and an exposure time of 180 ps. In the course of foil explosion, rapidly expanding objects resembling the core and corona of an exploded wire were observed. It is shown that the core of the exploded foil has a complicated time-varying structure.     

Synthesis of the β-amyloid fragment <Superscript>5</Superscript>RHDSGY<Superscript>10</Superscript> and its isomers

The peptide RHDSGY, a fragment of the human β-amyloid Zn-binding site, and its isomers RH(D-Asp)SGY and RH(β-Asp)SGY have been obtained as amides by means of solid-phase synthesis and analyzed by HPLC and various mass spectrometric methods. The problem of low yield of the RHDSGY peptide and its isomers attributed to 9-fluorenylmethoxycarbonyl (Fmoc)-amino acids and/or formation of such side-products as RH(β-Asp)SGY (or RHDSGY during synthesis of RH(β-Asp)SGY) and RH(Asp-imide) SGY was solved via selection of individual reagents for removal of Fmoc groups from α-amino groups of the growing peptide chain.     

A critical evaluation of intrapopulation variation of δ<Superscript>13</Superscript>C and isotopic evidence of individual specialization

Individual variation in the diet of consumers is common in many ecological systems and has important implications for the study of population dynamics, animal behavior, and evolutionary or ecological interactions. Ecologists frequently quantify the niche of a population by intensive analyses of gut contents and feeding behaviors of consumers. Inter-individual differences in ¹³C signature can indicate long term differences in feeding behavior, often unattainable by a single snapshot analysis of gut contents. If a consumers food sources have unique ¹³C signatures, then the intrapopulation variation in ¹³C may be useful for quantifying diet variation and detecting isotopic evidence of individual specialization. However, intrapopulation variation in ¹³C can underestimate or overestimate dietary variation, and therefore is not directly equivalent to a dietary based niche. In this paper we show that intrapopulation variability of ¹³C in consumers critically depends on the isotopic range and distribution of food sources. Our analyses fundamentally challenge how we interpret the intrapopulation isotopic variance of ¹³C, and how we evaluate isotopic evidence of individual specialization.