Quantitative proteomic analysis of mouse testis uncovers cellular pathways associated with bisphenol A (BPA)-induced male infertility.

Quantitative proteomic analysis was performed using iTRAQ to explore the potential regulation of differentially expressed proteins (DEPs) by bisphenol A (BPA) in murine testis. BPA was intraperitoneally injected into mice at a dose of 100 mg/kg body weight for 7 consecutive days. After BPA treatment, the histopathology changes of testis were examined. The circulating levels of testosterone (T) and estradiol (E2) were determined. iTRAQ was used to assess the expression levels of DEPs and to reveal potential interactions between different DEPs. Results showed that BPA caused histological damage in testicular tissues. The levels of T and E2 were affected by BPA exposure. The abundances of orosomucoid 1 (Orm1), haptoglobin (Hp), and insulin-like 3 (Insl3) were significantly lower in BPA-treated mice than those in control mice. The expression changes in the above-mentioned proteins were further validated at the protein level using Western blot analysis. We concluded that BPA affects histological morphology of testis and sex hormone productions. The regulation of key proteins (such as Orm1, Hp and Insl3) may reflect that these proteins may serve as important factors in male reproductive disorders caused by BPA, and these proteins are probably biomarkers for infertility caused by endocrine disrupting chemicals.

Icariin protects vascular endothelial cells from oxidative stress through inhibiting endoplasmic reticulum stress.

OBJECTIVE: To investigate the protective effect and underlying mechanism(s) of icariin (ICA) in preventing hydrogen peroxide (H2O2)-induced vascular endothelial cell injury via endoplasmic reticulum stress (ERS). METHODS: To study the effects of ICA on H2O2-induced damage, we used the cell counting kit-8 assay to detect cell viability and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay to determine cell adhesion and apoptosis, respectively. Spectrophotometry and enzyme-linked immunosorbent assay were used to measure the expression levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Subsequently, glucose-regulated protein 78 (GRP78), activating transcription factor-4 (ATF4) and eukaryotic initiation factor-2α (eIF2α) were detected using Western blotting. RESULTS: In human umbilical vein endothelial cells, different concentrations of ICA exhibited multiple effects, including reduced H2O2 damage, improved cell viability and adhesion, reduced cell apoptosis and increased SOD and GSH-Px activity. Among the ICA concentrations used, only the H2O2 + 100 µmol/L ICA group had significant differences compared to the H2O2 group. ERS activators H2O2 and dl-dithiothreitol (DTT) significantly increased GRP78, ATF4 and eIF2α expressions, decreased cell activity and reduced SOD and GSH-Px activity. In contrast, the H2O2 + 100 µmol/L ICA and H2O2 + 100 µmol/L ICA + DTT groups had significant inhibitory effects on the expressions of GRP78, ATF4 and eIF2α proteins, showing enhanced cell viability and SOD and GSH-Px activity. CONCLUSION: The results showed the dose-dependent effects of ICA against H2O2-induced injury in vascular endothelial cells. The inhibition of GRP78, ATF4 and eIF2α protein expressions in the ERS, and the subsequent alleviation of oxidative stress damage, might be the molecular mechanism.

[Reproduction-related proteins differentially expressed in the testes of the mice with kidney-yang or kidney-yin deficiency].

OBJECTIVE: To compare the differentially expressed proteins in mice with kidney-yang deficiency and those with kidney-yin deficiency induced by hydrocortisone, and explore the similar and different material bases of male infertility caused by the two types of kidney deficiency. METHODS: Thirty Kunming mice were equally randomized into a normal control, a kidney-yang deficiency and a kidney-yin deficiency group. The animals of the normal control group were injected intraperitoneally with normal saline at 0.2 ml qd for 7 days, while those of the latter two groups with hydrocortisone at 25 mg/kg/d for 10 days and 50 mg/kg/d for 7 days, respectively, for establishment of kidney-yang deficiency and kidney-yin deficiency models. Then the pathological changes in the testicular tissue of the mice were observed by HE staining and the differentially expressed proteins were compared among different groups using isobaric tags for relative and absolute quantitation (iTRAQ) and the bioinformatics method. RESULTS: Sod1 was found to be a reproduction-related node protein differentially expressed in the testis tissues of the two types of kidney-deficiency mice, more highly expressed in the kidney-yin than in the kidney-yang deficiency group (P < 0.05). Five reproduction-associated node proteins were co-expressed in the testes of the two groups of kidney-deficiency mice, with significantly up-regulated expression of Rps28 and down-regulated expressions of Rpl11, Rplp2, Svs2 and Svs3a (P < 0.01). CONCLUSIONS: Sod1 may be one of the key material bases for the differentiation of male infertility caused by kidney-yang deficiency from that induced by kidney-yin deficiency, while Rps28, Rpl11, Rplp2, Svs2 and Svs3a may be the common material bases of male infertility caused by the two types of kidney deficiency.

[Expression of G-protein coupled estrogen receptor in the testis of the male mouse with kidney yin or kidney yang deficiency and its impact on the reproductive function of the mouse].

OBJECTIVE: To investigate the expression of the G-protein coupled estrogen receptor (GPER) in the testis of the male mouse with kidney yin or kidney yang deficiency and its influence on the reproductive function of the mouse. METHODS: We randomized 30 six-week-old male Kunming mice into three groups of equal number: kidney yang deficiency, kidney yin deficiency, and normal control, and established the models of kidney yang deficiency and kidney yin deficiency by peritoneal injection of hydrocortisone at 50 mg/kg for 5 days and 25 mg/kg for 10 days, respectively. We observed the behavioral changes of the mice using the elevated plus-maze, exhaustive swimming and field experiment, examined the semen quality with the automatic sperm quality analyzer, calculated the average number of the offspring, measured the serum testosterone (T) and estradiol (E2) levels and T/E2 ratio by Roche electrochemiluminescence assay, and determined the localization and expression of GPER in the testis by immunohistochemistry and immunofluorescence staining. RESULTS: Compared with the mice with kidney yin deficiency, those with kidney yang deficiency showed remarkably fewer entries into the open arm and central area (P <0.05) and shorter time of exhaustive swimming (P <0.05), but no statistically significant difference in the time spent in the open arm or the central area (P >0.05); the latter group also exhibited significant decreases in the epididymal sperm count (ï¼»7.27 ± 1.30ï¼½ vs ï¼»3.05 ± 1.06ï¼½ ×108/g, P <0.01), sperm motility (ï¼»54.15 ± 13.52ï¼½ vs ï¼»51.57 ± 8.75ï¼½ %, P <0.01) and average number of the offspring (6.46 vs 4.33, P <0.05), a slight increase in the rate of morphologically abnormal sperm (ï¼»13.42 ± 2.32ï¼½ vs ï¼»15.39 ± 2.48ï¼½ %, P >0.05), and markedly reduced serum T (ï¼»24.96 ± 6.18ï¼½ vs ï¼»16.72 ± 5.92ï¼½ ng/dl,P <0.05), E2 (ï¼»19.81 ± 4.01ï¼½ vs ï¼»15.24 ± 1.11ï¼½ pg/ml,P <0.05) and T/E2 ratio (1.41 vs 1.25, P <0.05). The expression of GPER was found in the cytoplasm of the Leydig cells, negative in the nuclei and cell membrane, significantly higher in the kidney yang than in the kidney yin deficiency group (P <0.05). CONCLUSIONS: The numbers of sperm and offspring decreased while the percentage of morphologically abnormal sperm increased in both the kidney yang and kidney yin deficiency mice, even more significantly in the former, which might be associated with the up-regulated expression of GPER in the testis of the mouse with kidney yang deficiency and consequently the reduced serum T level and T/E2 ratio.

Bell's Nonlocality Can be Detected by the Violation of Einstein-Podolsky-Rosen Steering Inequality.

Recently quantum nonlocality has been classified into three distinct types: quantum entanglement, Einstein-Podolsky-Rosen steering, and Bell's nonlocality. Among which, Bell's nonlocality is the strongest type. Bell's nonlocality for quantum states is usually detected by violation of some Bell's inequalities, such as Clause-Horne-Shimony-Holt inequality for two qubits. Steering is a manifestation of nonlocality intermediate between entanglement and Bell's nonlocality. This peculiar feature has led to a curious quantum phenomenon, the one-way Einstein-Podolsky-Rosen steering. The one-way steering was an important open question presented in 2007, and positively answered in 2014 by Bowles et al., who presented a simple class of one-way steerable states in a two-qubit system with at least thirteen projective measurements. The inspiring result for the first time theoretically confirms quantum nonlocality can be fundamentally asymmetric. Here, we propose another curious quantum phenomenon: Bell nonlocal states can be constructed from some steerable states. This novel finding not only offers a distinctive way to study Bell's nonlocality without Bell's inequality but with steering inequality, but also may avoid locality loophole in Bell's tests and make Bell's nonlocality easier for demonstration. Furthermore, a nine-setting steering inequality has also been presented for developing more efficient one-way steering and detecting some Bell nonlocal states.

Miscibility and ordered structures of MgO-ZnO alloys under high pressure.

The MgxZn(1-x)O alloy system may provide an optically tunable family of wide band gap materials that can be used in various UV luminescences, absorption, lighting, and display applications. A systematic investigation of the MgO-ZnO system using ab initio evolutionary simulations shows that MgxZn(1-x)O alloys exist in ordered ground-state structures at pressures above about 6.5 GPa. Detailed enthalpy calculations for the most stable structures allowed us to construct the pressure-composition phase diagram. In the entire composition, no phase transition from wurzite to rock-salt takes place with increasing Mg content. We also found two different slops occur at near x = 0.75 of Eg-x curves for different pressures, and the band gaps of high pressure ground-state MgxZn(1-x)O alloys at the Mg concentration of x > 0.75 increase more rapidly than x < 0.75.

Nitrogen concentration driving the hardness of rhenium nitrides.

The structures and properties of rhenium nitrides are studied with density function based first principle method. New candidate ground states or high-pressure phases at Re:N ratios of 3:2, 1:3, and 1:4 are identified via a series of evolutionary structure searches. We find that the 3D polyhedral stacking with strong covalent N-N and Re-N bonding could stabilize Re nitrides to form nitrogen rich phases, meanwhile, remarkably improve the mechanical performance than that of sub-nitrides, as Re3N, Re2N, and Re3N2. By evaluating the trends of the crystal configuration, electronic structure, elastic properties, and hardness as a function of the N concentration, we proves that the N content is the key factor affecting the metallicity and hardness of Re nitrides.

Pressure induced phase transition in MH2 (M = V, Nb).

High-pressure structures of MH2 (M = V, Nb) are explored through ab initio evolutionary methodology. As the same main group metal hydrides, VH2 and NbH2 adopt the same tetragonal structure with space group Fm-3m at low pressures. However, at high pressures VH2 and NbH2 possess Pnma and P63mc phases differently. The two phase transitions are both the first order phase transition identified by volume collapses. Our calculations suggest that two high-pressure structures have both dynamical and mechanical stability up to 100 GPa. Pnma VH2 and P63mc NbH2 are metallic phases demonstrated by the band structure and density of states. However, their superconducting temperatures are only several Kelvins.

Cubic gauche-CN: A superhard metallic compound predicted via first-principles calculations.

In this paper, we suggest a novel potential superhard material, a new carbon nitride phase consisted of sp(3) hybridized bonds, possessing a cubic P2(1)3 symmetry (8 atoms/cell, labeled by cg-CN) which is similar to cubic gauche nitrogen (cg-N) by first-principles calculations. It is a metallic compound, while most of other superhard materials are insulators or semiconductors. The Vickers hardness of cg-CN is 82.56 GPa, and if we considered the negative effect of metallic component on hardness, it is 54.7 GPa, which is much harder than any other metallic materials. It is found that a three-dimensional C-N network is mainly responsible for the high hardness. Both elastic constant and phonon-dispersion calculations show that this structure remains mechanically and dynamically stable in the pressure ranges from 0 to 100 GPa. Furthermore, we compared our results with many other proposed structures of carbon nitride with 1:1 stoichiometry and found that only cg-CN is the most favorable stable crystal structure. Formation enthalpies calculations demonstrate that this material can be synthesizable at high pressure (12.7-36.4 GPa).

Hydrogen bond symmetrization and superconducting phase of HBr and HCl under high pressure: An ab initio study.

Ab initio calculations are performed to probe the hydrogen bonding, structural, and superconducting behaviors of HBr and HCl under high pressure. The calculated results show that the hydrogen bond symmetrization (Cmc2(1)-->Cmcm transition) of HBr and HCl occurs at 25 and 40 GPa, respectively, which can be attributed to the symmetry stretching A(1) mode softening. After hydrogen bond symmetrization, a pressure-induced soft transverse acoustic phonon mode of Cmcm phase is identified and a unique metallic phase with monoclinic structure of P2(1)/m (4 molecules/cell) for both compounds is revealed by ab initio phonon calculations. This phase preserves the symmetric hydrogen bond and is stable in the pressure range from 134 to 196 GPa for HBr and above 233 GPa for HCl, while HBr is predicted to decompose into Br(2)+H(2) above 196 GPa. Perturbative linear-response calculations predict that the phase P2(1)/m is a superconductor with T(c) of 27-34 K for HBr at 160 GPa and 9-14 K for HCl at 280 GPa.

Order-disorder phase transition and dissociation of hydrogen sulfide under high pressure: ab initio molecular dynamics study.

The structural and dynamical properties of phase IV and V of hydrogen sulfide were investigated by means of extensive ab initio molecular dynamics simulations. Starting from an experimental proposal for the structure of phase IV, an Ibca symmetry with a stable hydrogen bonding network is found at 15 GPa and 100 K. Molecular dynamics simulations at increasing temperature and at the pressure of 15 GPa suggest that phase IV will transform to a proton disordered structure at 15 GPa and 350 K. The newfound structure has a hexagonal lattice of P63/mmc symmetry, which is believed to be the remaining crystalline structure of phase V. The high mobility of protons in phase V is believed to be the key point to the dissociation and decomposition of hydrogen sulfide.

The crystal structure and superconducting properties of monatomic bromine.

The crystal structure and superconducting properties of monatomic bromine under high pressure have been studied by first-principles calculations. We have found the following phase transition sequence with increasing pressure: from body-centered orthorhombic (bco, phase II) to body-centered tetragonal structure (bct, phase III) at 126 GPa, then to face-centered cubic structure (fcc, phase IV) at 157 GPa, which is stable at least up to 300 GPa. The calculated superconducting critical temperature T(c) = 1.46 K at 100 GPa is consistent with the experimental value of 1.5 K. In addition, our results of T(c) decrease with increasing pressure in all the monatomic phases of bromine, similar to monatomic iodine. Further calculations show that the decrease of λ with pressure in phase IV is mainly attributed to the weakening of the 'soft' vibrational mode caused by pressure.

New high-pressure phase of BaH2 predicted by ab initio studies.

Pressure-induced phase transitions of BaH2 have been studied by ab initio calculations. Our results show that BaH2 transforms from the cotunnite structure to the InNi2-type structure at about 2.3 GPa, which is in agreement with experimental results. The InNi2 phase is predicted to be an insulator and transforms to a metallic phase with an AlB2-type structure at about 34 GPa. Under higher pressure, a post-AlB2 phase with the YbZn2-type structure (space group Imma, 4 f.u./cell) is predicted, which is both dynamically and mechanically stable. Analysis of the enthalpies for both AlB2 and YbZn2 phases further supports the existence of this new phase. The [AlB2 → YbZn2] structural phase transition is identified as a second-order nature, driven by the softening of the transverse acoustic phonon mode at the L point (0.5, 0.0, 0.5).