Spatial scale dependence of the species diversityin Tianmu Mountain and its relationship with spatial patterns by using multifractal analysis

This study took the Tianmu Mountain National Natural Preservation Area in western Zhejiang Province as an example 1) to quantify the species diversity with selected species indices including Shannon-Wiener index (H), Margalef index (K) and Evenness index (E) at different spatial scales, 2) to analyze the spatial distribution patterns of the species diversity by multifractal parameters such as the singularity index α, its fractal dimension f(α), the f(α)–α spectrum range (SR) and its symmetry (Dist) using the multifractal theory, and 3) to determine their relationships. Results of nonlinear regression analysis with power functions showed that increasing spatial scale resulted in increasing H but decreasing E and K, indicating that the scale dependence of species diversity existed. By using the multifractal method, it was indicated that species spatial distribution had multifractal features. Moreover, strong linear relationships of the diversity indices H, E and K with α_min and clear nonlinear associations of the diversity indices H, E and K with power functions for SR and Dist were found. Since interactions of the species diversity and the spatial characteristics are very complex, the above mentioned relationships need further validation along with precise explanations of any correlations among their ecological processes.     

Energetics of Contraction in Phasic and Tonic Skeletal Muscles of the Chicken

Comparative energetics of chicken latissimus dorsi muscles, tonic anterior (ALD) and phasic posterior (PLD), were investigated by measuring initial heat production. Heat components were analyzed in terms of the equation: E = A + W + α_F(L) + f(P, t) As the muscles were stretched by increments, heat produced in isometric twitches and tetani decreased in a linear fashion. Two processes are involved: one tension independent, the activation heat, or A; and the other tension dependent, W_i + α_F(L) + f(P, t). In twitches, A, per unit tension, is equivalent in the PLD and ALD. Tension-dependent heat, per unit tension, is greater in the PLD due to W_i; but tension-time-related heat, f(P, t), per unit tension, is similar in both muscles. In tetanic contractions, differences in A and f(P, t), per unit tension, are attributed to the greater V_max in the PLD. The differences in the energetics of isometric contractions in the PLD and ALD, therefore, can be explained by inherent differences in tension development, compliance, and myosin and reticular ATPase activities. Data from isotonic twitches were quantified by means of the equivalent tension technique. Both muscles exhibited an extra heat associated with shortening, α_F(L). In the PLD, the ratio α_F/P_ot is greater; it is load independent and ½ the value of a/P_o in both muscles. Enthalpy efficiency, W_e + W_i/E, is comparable in both muscles. A Fenn effect is observed only when isotonic energy liberation is compared to a decreasing isometric energy expenditure base line.     

Roles of α-methyl trans-cyclopropane groups in behavior of mixed mycolic acid monolayers

Mixed Langmuir films of type 1 alpha-(α-) and keto-mycolic acids (MAs) were investigated to understand the roles of α-methyl trans-cyclopropane containing keto-MA in determining the physical and chemical properties of the monolayers. Surface pressure (π) vs. mean molecular area (A) isotherms were measured at constant mole fractions defined as the ratio of the keto-MA molarity to the total molarity of α-MA and keto-MA (X_keto) at 25?°C and 37?°C. A and the elastic modulus (E) of the mixed monolayer were compared for different X_keto at fixed π values. In keto-MA rich monolayers, A values were much larger than values of the combined areas of α-MA and keto-MA, while the E values were close to those of solid keto-MA monolayers. A and E were also plotted against the mole fraction of α-methyl trans-cyclopropane containing keto-MA, which showed that the α-methyl trans-cyclopropane group stabilized the W-form conformation of mycolic acids in monolayers, and rendered them solid state. Furthermore, a comparison of the experimental results and the α-methyl trans-cyclopropane content in cell-wall MAs from various strains indicated that the ratio of trans-cyclopropane content was important in determining the nature of the mixed MA layer.     

The permeability coefficient of albumin of the isolated rat mesentery Modification by some mediators of inflammation,cyclic AMP and calcium

In order to study the mechanisms whereby mediators of inflammation exert their exudative effects, we used isolated rat mesentery placed as a separation membrane between the two compartments of a diffusion cell. In this experimental arrangement, the permeability coefficient of albumin (P_A) can be easily computed from the equilibration rate of ¹²⁵I-labelled albumin added to one compartment. Histamine, bradykinin, serotonin and prostaglandins A₁, A₂, E₁, E₂, F_1α and F_2α all increased P_A to some extent, the maximal values being approx. +60%. Dibutyryl-cyclic AMP, theophylline and isoproterenol also increased P_A, thus suggesting involvement of cyclic AMP. Direct measurements of this nucleotide confirmed this hypothesis; furthermore, a linear relation between cyclic AMP levels and P_A could be demonstrated. In contrast, cyclic GMP is probably not involved in the control of P_A. Calcium-depleted tissues had a low P_A (approx. 40% below controls), and did not respond to exogenous prostaglandin E₁. These results suggest that transmesenteric passage of albumin is at least partly controlled by cyclic AMP and intracellular Ca²⁺ levels.     

8-Substituted 1,3-dimethyltetrahydropyrazino[2,1-f]purinediones: Water-soluble adenosine receptor antagonists and monoamine oxidase B inhibitors

Multitarget approaches, i.e., addressing two or more targets simultaneously with a therapeutic agent, are hypothesized to offer additive therapeutic benefit for the treatment of neurodegenerative diseases. Validated targets for the treatment of Parkinson’s disease are, among others, the A_2A adenosine receptor (AR) and the enzyme monoamine oxidase B (MAO-B). Additional blockade of brain A₁ ARs may also be beneficial. We recently described 8-benzyl-substituted tetrahydropyrazino[2,1-f]purinediones as a new lead structure for the development of such multi-target drugs. We have now designed a new series of tetrahydropyrazino[2,1-f]purinediones to extensively explore their structure–activity-relationships. Several compounds blocked human and rat A₁ and A_2AARs at similar concentrations representing dual A₁/A_2A antagonists with high selectivity versus the other AR subtypes. Among the best dual A₁/A_2AAR antagonists were 8-(3-(4-chlorophenyl)propyl)-1,3-dimethyl-6,7,8,9-tetrahydropyrazino[2,1-f]purine-2,4(1H,3H)-dione (41, K_i human A₁: 65.5 nM, A_2A: 230 nM; K_i rat A₁: 352 nM, A_2A: 316 nM) and 1,3-dimethyl-8-((2-(thiophen-2-yl)thiazol-4-yl)methyl)-6,7,8,9-tetrahydropyrazino[2,1-f]purine-2,4(1H,3H)-dione (57, K_i human A₁: 642 nM, A_2A: 203 nM; K_i rat A₁: 166 nM, A_2A: 121 nM). Compound 57 was found to be well water-soluble (0.7 mg/mL) at a physiological pH value of 7.4. One of the new compounds showed triple-target inhibition: (R)-1,3-dimethyl-8-(2,1,3,4-tetrahydronaphthalen-1-yl)-6,7,8,9-tetrahydropyrazino[2,1-f]purine-2,4(1H,3H)-dione (49) was about equipotent at A₁ and A_2AARs and at MAO-B (K_i human A₁: 393 nM, human A_2A: 595 nM, IC₅₀ human MAO-B: 210 nM) thus allowing future in vivo explorations of the intended multi-target approach.     

Cross-Correlation Functions for a Neuronal Model

Cross-correlation functions, R_XY(t,τ), are obtained for a neuron model which is characterized by constant threshold θ, by resetting to resting level after an output, and by membrane potential U(t) which results from linear summation of excitatory postsynaptic potentials h(t). The results show that: (1) Near time lag τ = 0, R_XY(t,τ) = f_U [θ-h(τ), t + τ] {h′(τ) + E_U [u′(t + τ)]} for positive values of this quantity, where f_U(u,t) is the probability density function of U(t) and E_U [u′(t + τ)] is the mean value function of U′(t + τ). (2) Minima may appear in R_XY(t,τ) for a neuron subjected only to excitation. (3) For large τ, R_XY(t,τ) is given approximately by the convolution of the input autocorrelation function with the functional of point (1). (4) R_XY(t,τ) is a biased estimator of the shape of h(t), generally over-estimating both its time to peak and its rise time.     

Thiodisaccharides with galactofuranose or arabinofuranose as terminal units: Synthesis and inhibitory activity of an exo β-d-galactofuranosidase

Thiodisaccharides having β-d-Galf or α-l-Araf units as non-reducing end have been synthesized by the SnCl₄- or MoO₂Cl₂-promoted thioglycosylation of per-O-benzoyl-d-galactofuranose (1), its 1-O-acetyl analogue 4, or per-O-acetyl-α-l-arabinofuranose (16) with 6-thioglucose or 6-thiogalactose derivatives. After convenient removal of the protecting groups, the free thiodisaccharides having the basic structure β-d-Galf(1→6)-6-thio-α-d-Glcp-OMe (5) or β-d-Galf(1→6)-6-thio-α-d-Galp-OMe (15) were obtained. The respective α-l-Araf analogues 18 and 20 were prepared similarly from 16. Alternatively, β-d-Galf(1→4)-4-thio-3-deoxy-α-l-Xylp-OiPr was synthesized by Michael addition to a sugar enone of 1-thio-β-d-Galf derivative, generated in situ from the glycosyl isothiourea derivative of 1. The free S-linked disaccharides were evaluated as inhibitors of the β-galactofuranosidase from Penicillium fellutanum, being 15 and 20 the more active inhibitors against this enzyme.     

1,3-Dialkyl-substituted tetrahydropyrimido[1,2-f]purine-2,4-diones as multiple target drugs for the potential treatment of neurodegenerative diseases

Adenosine receptors and monoamine oxidases are drug targets for neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease. In the present study we prepared a library of 55 mostly novel tetrahydropyrimido[2,1-f]purinediones with various substituents in the 1- and 3-position (1,3-dimethyl, 1,3-diethyl, 1,3-dipropyl, 1-methyl-3-propargyl) and broad variation in the 9-position. A synthetic strategy to obtain 3-propargyl-substituted tetrahydropyrimido[2,1-f]purinedione derivatives was developed. The new compounds were evaluated for their interaction with all four adenosine receptor subtypes and for their ability to inhibit monoamine oxidases (MAO). Introduction of mono- or di-chloro-substituted phenyl, benzyl or phenethyl residues at N9 of the 1,3-dimethyl series led to the discovery of a novel class of potent MAO-B inhibitors, the most potent compound being 9-(3,4-dichlorobenzyl)-1,3-dimethyl-6,7,8,9-tetrahydropyrimido[1,2-f]purine-2,4(1H,3H)-dione (21g, IC₅₀ human MAO-B: 0.0629 μM), which displayed high selectivity versus the other investigated targets. Potent dually active A₁/A_2A adenosine receptor antagonists were identified, for example, 9-benzyl-1-methyl-3-propargyl-6,7,8,9-tetrahydropyrimido[1,2-f]purine-2,4(1H,3H)dione (19f, K_i, human receptors, A₁: 0.249 μM, A_2A: 0.253 μM). Several compounds showed triple-target inhibition, the best compound being 9-(2-methoxybenzyl)-1-methyl-3-(prop-2-ynyl)-6,7,8,9-tetrahydro pyrimido [1,2-f]purine-2,4(1H,3H)-dione (19g, K_i A₁: 0.605 μM, K_i A_2A: 0.417 μM, IC₅₀ MAO-B: 1.80 μM). Compounds inhibiting several different targets involved in neurodegeneration may exhibit additive or even synergistic effects in vivo.     

Influence of the PsbA1/PsbA3, Ca2+/Sr2+ and Cl−/Br− exchanges on the redox potential of the primary quinone QA in Photosystem II from Thermosynechococcus elongatus as revealed by spectroelectrochemistry

Ca²⁺ and Cl^? ions are essential elements for the oxygen evolution activity of photosystem II (PSII). It has been demonstrated that these ions can be exchanged with Sr²⁺ and Br^?, respectively, and that these ion exchanges modify the kinetics of some electron transfer reactions at the Mn₄Ca cluster level (Ishida et al., J. Biol. Chem. 283 (2008) 13330–13340). It has been proposed from thermoluminescence experiments that the kinetic effects arise, at least in part, from a decrease in the free energy level of the Mn₄Ca cluster in the S₃ state though some changes on the acceptor side were also observed. Therefore, in the present work, by using thin-layer cell spectroelectrochemistry, the effects of the Ca²⁺/Sr²⁺ and Cl^?/Br^? exchanges on the redox potential of the primary quinone electron acceptor Q_A, E_m(Q_A/Q_A^?), were investigated. Since the previous studies on the Ca²⁺/Sr²⁺ and Cl^?/Br^? exchanges were performed in PsbA3-containing PSII purified from the thermophilic cyanobacterium Thermosynechococcus elongatus, we first investigated the influences of the PsbA1/PsbA3 exchange on E_m(Q_A/Q_A^?). Here we show that i) the E_m(Q_A/Q_A^?) was up-shifted by ca. + 38 mV in PsbA3-PSII when compared to PsbA1-PSII and ii) the Ca²⁺/Sr²⁺ exchange up-shifted the E_m(Q_A/Q_A^?) by ca. + 27 mV, whereas the Cl^?/Br^? exchange hardly influenced E_m(Q_A/Q_A^?). On the basis of the results of E_m(Q_A/Q_A^?) together with previous thermoluminescence measurements, the ion-exchange effects on the energetics in PSII are discussed.     

Does the water-oxidizing Mn4CaO5 cluster regulate the redox potential of the primary quinone electron acceptor QA in photosystem II? A study by Fourier transform infrared spectroelectrochemistry

Redox titration using fluorescence measurements of photosystem II (PSII) has long shown that impairment of the water-oxidizing Mn₄CaO₅ cluster upshifts the redox potential (E_m) of the primary quinone electron acceptor Q_A by more than 100 mV, which has been proposed as a photoprotection mechanism of PSII. However, the molecular mechanism of this long-distance interaction between the Mn₄CaO₅ cluster and Q_A in PSII remains unresolved. In this study, we reinvestigated the effect of depletion of the Mn₄CaO₅ cluster on E_m(Q_A⁻/Q_A) using Fourier transform infrared (FTIR) spectroelectrochemistry, which can directly monitor the redox state of Q_A at an intended potential. Light-induced FTIR difference measurements at a series of electrode potentials for intact and Mn-depleted PSII preparations from spinach and Thermosynechococcus elongatus showed that depletion of the Mn₄CaO₅ cluster hardly affected the E_m(Q_A⁻/Q_A) values. In contrast, fluorescence spectroelectrochemical measurement using the same PSII sample, electrochemical cell, and redox mediators reproduced a large upshift of apparent E_m upon Mn depletion, whereas a smaller shift was observed when weaker visible light was used for fluorescence excitation. Thus, the possibility was suggested that the measuring light for fluorescence disturbed the titration curve in Mn-depleted PSII, in contrast to no interference of infrared light with the PSII reactions in FTIR measurements. From these results, it was concluded that the Mn₄CaO₅ cluster does not directly regulate E_m(Q_A⁻/Q_A) to control the redox reactions on the electron acceptor side of PSII.     

Synthesis, characterization, structures and DNA-binding properties of complexes [Ru(bpy)2(L)] (L = ptdb, ptda and ptdp) with asymmetric intercalative ligands

A series of Ru(II) polypyridyl complexes [Ru(bpy)₂(ptdb)](ClO₄)₂ (1), [Ru(bpy)₂(ptda)](ClO₄)₂ (2) and [Ru(bpy)₂(ptdp)](ClO₄)₂ (3) with asymmetric intercalative ligands have been synthesized and characterized by EA, mass spectra, ¹H NMR and cyclic voltammetry. The crystal structure of complex 1 has been determined. The DNA-binding properties of the complexes were investigated by absorption titration, luminescence spectroscopy and viscosity measurements. The experimental results suggest that all these complexes bind to DNA in an intercalation mode. The results also show that the order of DNA-binding affinities (A) of this series of complexes is A(1) < A(2) < A(3). It is further confirmed that a ligand planarity of the complexes is a very important factor in affecting the DNA-binding behaviors of such complexes. Theoretical studies for these complexes were also carried out with the density functional theory (DFT) method. The trend in the DNA-binding affinities of this series of complexes can be reasonably explained by the synthetical considerations of the calculated planarity of intercalative ligands, some frontier molecular orbital energies of the complexes and the planarity area (S) of the intercalative ligands.     

Noise analysis and relaxation experiments of transport of hydrophobic anions across lipid membranes at equilibrium and nonequilibrium

Under equilibrium and nonequilibnum steady-stale conditions the spectral intensity of current noise S_J(f) generated by the transport of hydrophobic unions across lipid bilayer membranes was investigated. The experimental results were compared with different reaction models S_J(f) showed a characteristic increase proportional to f² between frequency-independent tails at low and high frequencies. This gradient was found to be independent of applied voltage which indicates the contribution of a single voltage-dependent reaction step of ion translocation across the membrane From the shape of S_J(f) at low frequencies the rate constant of ion desorption from the membrane into the aqueous phase could be estimated. Unambiguous evidence for the application of a general model, which includes the coupling of slow ion diffusion in the aqueous phase to ion adsorption/desorption at the membrane interface, could not be obtained from the low-frequency shape of S_J(f). The shot noise of this ion transport determines the amplitude of S_J(f) at high frequencies which decreases with increasing voltage applied. Analysis of voltage-jump current-relaxation experiments and of current noise carried cut on one membrane yielded significant differences of the derived ion partition coefficient. This deviation is qualitatively described on the basis of incomplete reaction steps.     

Species-dependence of the redox potential of the primary quinone electron acceptor QA in photosystem II verified by spectroelectrochemistry

The redox potentials E_m(Q_A/) of the primary quinone electron acceptor Q_A in oxygen-evolving photosystem II complexes of three species were determined by spectroelectrochemistry. The E_m(Q_A/) values were experimentally found to be −162 ± 3 mV for a higher plant spinach, −171 ± 3 mV for a green alga Chlamydomonas reinhardtii and −104 ± 4 mV vs. SHE for a red alga Cyanidioschyzonmerolae. On the basis of possible deviations for the experimental values, as estimated to differ by 9-29 mV from each true value, plausible causes for such remarkable species-dependence of E_m(Q_A/) are discussed, mainly by invoking the effects of extrinsic subunits on the delicate structural environment around Q_A.     

Conformational analysis of 1,2:3,4-di-O-isopropylidene-α-d-galacto-octopyranose derivatives: a 1H- and 13C-N.M.R.-spectral and x-ray comparative study

The pyranoid conformations of 7-acetamido-6,7,8-trideoxy-1,2:3,4-di-O-isopropylidene-d-glycero-α-d-galacto-octopyranose (3) and 7-acetamido-7,8-dideoxy-1,2:3,4-di-O-isopropylidene-l-threo-α-d-galacto-octopyranose (4) in solution have been determined by calculation of the dihedral angles from the vicinal, proton-proton coupling-constants, using three modifications of the Karplus equation. Of these, only the equation ³J(HCCH)(φ)  (7.48  0.74 -ΣδE_x)  (2.03  0.17 ΣE_x)cos φ + (4.60  0.23 ΣδE_x)cos 2φ + 0.06 (Σ ± ΔE_x)sin φ + 0.62 (Σ ± ΔE_x)sin 2φ indicates that the pyranoid part of 3 and 4 has the °S₂ conformation, very slightly distorted towards °H₅, in agreement with the conformations determined for the crystalline state. Analysis of the ¹H-n.m.r. data for a series of 1,2:3,4-di-O-isopropyl-idene-α-d-galacto-octopyranose derivatives shows that the pyranoid parts of these compounds adopt the same conformation as that found for 3 and 4.     

Distinct effects of the C-terminal octapeptide of cholecystokinin and of a cholera toxin pretreatment on the kinetics of rat pancreatic adenylate cyclase activity

(1) The kinetic parameters of rat pancreatic adenylate cyclase were evaluated, using GTP, p[NH]ppG or GTPγS as nucleotide activator, cholecystokinin as peptide hormone, and GDPβS and dibutyryl cyclic GMP as inhibitors of guanosine triphosphate and CCK-8, respectively. The time courses of activation and the degree of activation at steady state (E_A/E_TOT) were compatible with a simple two-state model of activation-deactivation based on a pseudo-monomolecular activation process (rate constant k₊₂, and a deactivation process (rate constant k_off) that included, depending on the activating nucleotide, the hydrolysis of GTP (rate constant k₂) and/or the dissociation of the intact nucleotide (rate constant k_?1), so that E_A/E_TOT = k₊₁/(k₊₁ + k₂ + k_?a). (2) The hormone CCK-8 increased the value of k₊₁ with GTP dose-dependently, from 0.2 to 10.9 min^?1. The value of k_?1 increased 0.01 to 0.3 min^?1 but the value of k₂ was unaltered at 7 min^?1, so that E_A/E_TOT increased 15-fold, from 4% to 61%. (3) A cholera toxin pretreatment at 30 μg/ml allowed also a large increase in E_A/E_TOT with GTP (up to 51%) but the underlying mechanism was different. It consisted of a 14-fold decrease in the k_off value of the GTP-activated enzyme (from 7 min^? to 0.5 min^?1) that corresponded to a reduction in GTPase activity. When testing the system with p[NH]ppG, two added effects of the cholera toxin pretreatment were observed: a 4-fold increase in the value of k₊₁ (from 0.2 to 0.8 min^?1) and the occurrence of a significant 0.3 min^?1 value for k_?1.     

Estrus synchronization affects WNT signaling in the porcine reproductive tract and embryos

The purpose of the study was to investigate an effect of estrus synchronization with prostaglandin (PG) F_2α and PMSG/hCG on WNT4, WNT5A, WNT7A, β-catenin (CTNNB1) and E-cadherin (CDH1) gene expression. The weight of the uterus, morphometrical parameters of the endometrium and the number of CL were recorded. The analysis of estradiol (E₂), prostaglandin (PG) F_2α and E₂ content in the uterine luminal flushings (ULFs) and progesterone (P₄) level in the blood serum were conducted. RNA was isolated from endometrial, luteal and embryonic tissue of pregnant non-synchronized (Control; n = 15) and pregnant synchronized (PGF_2α/PMSG/hCG; n = 15) pigs. Whereas there was no change in uterine weight, differences in height of endometrial surface and glandular epithelium were found. However, height of the endometrium, number of the glands and capillaries were unaffected. The total number of the CLs was higher (P < 0.05) in animals treated with PGF_2α/PMSG/hCG. The amount of E₂ and P₄ was lower (P < 0.05, P < 0.001, respectively) in pregnant gilts administrated with PGF_2α/PMSG/hCG. The concentration of PGF_2α in ULFs was not affected by hormonal management, while PGE₂ was higher (P < 0.01) in hormonally in comparison to non-hormonally treated pigs. The content of WNT4 mRNA in conceptuses increased on particular Days studied in Control and PGF_2α/PMSG/hCG administered animals. WNT7A and CTNNB1 were affected by PGF_2α/PMSG/hCG treatment in both conceptuses (P < 0.001, P < 0.05) and endometrial tissue (P < 0.001, P < 0.01). The PGF_2α/PMSG/hCG treatment resulted in elevated expression of WNT4 (P < 0.001) and CTNNB1 (P < 0.05) in luteal tissue in comparison to the Control gilts. Moreover, luteal amount of WNT5A mRNA was higher in PGF_2α/PMSG/hCG animals in comparison to the Control group (P < 0.05). Presented data show that exogenous hormones administration can affect gene expression in the porcine reproductive tract and embryo.     

Synthesis, crystal structure, luminescence and thermal decomposition kinetics of Eu(III) complex with 2,4-dichlorobenzoic acid and 2,2′-bipyridine

The complex of [Eu(2,4-DClBA)₃(bipy)]₂ (2,4-DClBA = 2,4-dichlorobenzoate; bipy = 2,2′-bipyridine) was obtained and characterized by elemental analysis, IR spectra, UV spectra, luminescence spectra, ¹H NMR spectra, single crystal X-ray diffraction and TG-DTG techniques. Two Eu³⁺ ions are connected by four carboxylate groups through bridging bidentate and bidentate chelating-bridging mode. The coordination number of europium ion is nine. The thermal decomposition behavior of the title complex under a static air atmosphere can be discussed by TG-DTG, SEM and IR techniques. The non-isothermal kinetics was investigated by using double equal-double steps method and Starink method. The mechanism function of the first decomposition step was determined. Meanwhile, the thermodynamic parameters (ΔH^≠, ΔG^≠ and ΔS^≠) and kinetic parameters (activation energy E and the pre-exponential factor A) were also calculated.     

Ring A-stereoisomers of 1-hydroxyvitamin D3 and their relative binding affinities for the intestinal 1α,25-dihydroxyvitamin D3 receptor protein

A set of eight 1-hydroxyvitamin D₃ compounds comprising the four possible (5Z)-1,3-diol stereoisomers and the corresponding (5E)-double bond isomers, has been prepared in order to assess the effect of 1,3-diol stereochemistry and 5,6-double bond geometry on binding affinity for the intestinal 1,25-(OH)₂D₃-receptor protein. The compounds were synthesized from either vitamin D₃ or 3-epivitamin D₃ via 3,5-cyclovitamin D intermediates. Competitive receptor binding assays establish that all changes from the natural ring A-configuration (1S, 3R, 5Z) lead to decreased binding affinity, and confirm the importance of the 1-hydroxy function since the conversion of stereochemistry at that center from 1α(S) to 1β(R) has the most pronounced effect on binding affinity (attenuation by more than three orders of magnitude). Other modifications (i.e., conversion at C-3, or cis to trans isomerization of the 5,6-double bond) decrease binding affinity by more moderate (ca. 10-fold) but cumulative factors.     

Estrus synchronization affects WNT signaling in the porcine reproductive tract and embryos

The purpose of the study was to investigate an effect of estrus synchronization with prostaglandin (PG) F_2α and PMSG/hCG on WNT4, WNT5A, WNT7A, β-catenin (CTNNB1) and E-cadherin (CDH1) gene expression. The weight of the uterus, morphometrical parameters of the endometrium and the number of CL were recorded. The analysis of estradiol (E₂), prostaglandin (PG) F_2α and E₂ content in the uterine luminal flushings (ULFs) and progesterone (P₄) level in the blood serum were conducted. RNA was isolated from endometrial, luteal and embryonic tissue of pregnant non-synchronized (Control; n = 15) and pregnant synchronized (PGF_2α/PMSG/hCG; n = 15) pigs. Whereas there was no change in uterine weight, differences in height of endometrial surface and glandular epithelium were found. However, height of the endometrium, number of the glands and capillaries were unaffected. The total number of the CLs was higher (P < 0.05) in animals treated with PGF_2α/PMSG/hCG. The amount of E₂ and P₄ was lower (P < 0.05, P < 0.001, respectively) in pregnant gilts administrated with PGF_2α/PMSG/hCG. The concentration of PGF_2α in ULFs was not affected by hormonal management, while PGE₂ was higher (P < 0.01) in hormonally in comparison to non-hormonally treated pigs. The content of WNT4 mRNA in conceptuses increased on particular Days studied in Control and PGF_2α/PMSG/hCG administered animals. WNT7A and CTNNB1 were affected by PGF_2α/PMSG/hCG treatment in both conceptuses (P < 0.001, P < 0.05) and endometrial tissue (P < 0.001, P < 0.01). The PGF_2α/PMSG/hCG treatment resulted in elevated expression of WNT4 (P < 0.001) and CTNNB1 (P < 0.05) in luteal tissue in comparison to the Control gilts. Moreover, luteal amount of WNT5A mRNA was higher in PGF_2α/PMSG/hCG animals in comparison to the Control group (P < 0.05). Presented data show that exogenous hormones administration can affect gene expression in the porcine reproductive tract and embryo.