Gaseous pollutant exposure affects semen quality in central China: a cross-sectional study

BACKGROUND

Limited studies have explored the association between gaseous pollutant exposures and male reproductive outcomes, and findings remained inconsistent.

OBJECTIVES

To evaluate the potential association  between gaseous pollutants and semen quality within different exposure windows. MATERIALS AND METHODS: We adopted semen quality data of 1852 subjects who attended the Reproductive Medicine Center of Renmin Hospital at Wuhan University during January 1st, 2013, to August 3rd, 2015. A generalized linear model was employed to assess the relationship between each exposure variable and sperm parameters in different exposure windows.

RESULTS

SO₂ exposure with lag 0-90 days was significantly associated with decreased sperm concentration (β: -1.362; 95% CI: -1.844, -0.879), sperm count (β: -2.979; 95% CI: -4.267, -1.691), and PR (β: -0.551; 95% CI: -0.710, -0.393). Similar trends were observed for SO₂ exposure with three other key periods (lag 0-9, 10-14, and 70-90 days). NO₂ exposure with lag 0-90 days was also associated with decreased sperm concentration (β: -0.517; 95% CI: -1.006, -0.027), sperm count (β: -1.914; 95% CI: -3.214, -0.615), and PR (β: -0.264; 95% CI: -0.425, -0.102). No relationship between gaseous pollutant exposure and ejaculate volume was observed in any exposure window.

DISCUSSION AND CONCLUSION

Our study indicated a strong adverse effect of gaseous pollutants on semen quality outcomes during the sperm development. Gaseous pollution exposure appeared to be more detrimental in the initial phase of spermatogenesis.

Results of a Search for Sub-GeV Dark Matter Using 2013 LUX Data

The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5  GeV/c^{2} using 1.4×10^{4}  kg day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.

Association of a novel SNP in the ASIP gene with skin color in black-bone chicken

The agouti signaling protein gene (ASIP) is a widely studied pigmentation gene that plays an important role in melanin synthesis. To determine the variety of ASIP expression in the Muchuan Black-Bone chicken, we examined genetic variation in the ASIP promoter region. A single nucleotide polymorphism (c.-1826A>T) was found to be associated with the skin color (dorsal and subalar) of black-bone chicken. Individuals with TT and AT genotypes had higher ASIP mRNA levels in the skin than did those with the AA genotype (P < 0.01). In addition, individuals with the TT genotype had higher ASIP mRNA levels than did those with the AT genotype (P < 0.05). Expression of melanogenesis-related genes (melanocortin 1 receptor and tyrosinase genes) was higher in the skin of chickens with the TT and AT genotypes than in those with the AA genotype (P < 0.01). A luciferase assay showed that promoter activity was higher in chickens with the TT genotype than in those with the AA genotype. Putative transcription factor prediction suggested that the c.-1826A>T mutation might shift the promoter binding affinity with differential transcription factors. In summary, we identified a novel mutation in the ASIP gene promoter that may affect chicken skin color by altering ASIP transcriptional activity.

Protective effect of Lycium barbarum polysaccharides against high-fat diet-induced renal injury and lipid deposition in rat kidneys

This study aimed to explore the protective effect of Lycium barbarum polysaccharides (LBPs) against hyperlipidemia and lipid-induced renal injury in a rat model. Male Sprague-Dawley rats (n=30) were randomly divided into three equal groups: a control group (fed a regular diet) and two experimental groups (fed a high-fat diet). By feeding rats a high-fat diet for 12 weeks, an animal model of hyperlipidemia was established, after which one experimental group received oral LBPs at a dose of 300 mg/kg per day. Blood lipids, renal function, and urinary proteins were measured after 12 weeks. Changes in renal pathology and expression levels of sterol regulatory element binding transcription factor 1 (SREBP-1), interleukin-6 (IL- 6), tumor necrosis factor-alpha (TNF-α), AMP-activated protein kinase (AMPK) were determined. Rats with hyperlipidemia induced by a high-fat diet showed increases in blood lipids and blood urea nitrogen, serum creatinine, and urinary protein, as well as increases in renal levels of SREBP-1, TNF-α, and IL-6 and decreases in renal levels of adiponectin and AMPK. Administration of LBPs restored blood lipid, blood urea nitrogen, serum creatinine, and urinary protein levels, downregulated renal levels of SREBP-1, TNF-α, and IL-6, and upregulated renal levels of adiponectin and AMPK. These results indicate that LBPs may mediate lipid metabolism, enhance anti-inflammatory responses, and ameliorate renal injury caused by lipid metabolism isorders in a rat model of hyperlipidemia.

Five alternative splicing variants of the TYR gene and their different roles in melanogenesis in the Muchuan black-boned chicken

1. The TYR gene encodes tyrosinase, a multifunctional enzyme that is essential for melanin biosynthesis in melanocytes. This experiment involved the cloning and characterisation of the TYR gene in chicken. Five alternative splice variants were identified in the black feather bulb and designated as TYR-AS1, TYR-AS2, TYR-AS3, TYR-AS4 and TYR-AS5. 2. Among the 11 chicken tissues examined, the feather bulb, comb and skin showed higher levels of all TYR variants. All TYR variants were expressed at significantly different levels in black and white feather bulbs (P < 0.05) and may be involved in melanin formation in plumage. Only TYR-AS1, which plays an important role in muscle melanogenesis, was significantly differentially expressed between black and white muscle (P < 0.01). All TYR variants were expressed at significantly different levels in black and white skin (P < 0.01). 3. The mRNA expression levels of the 5 variants were closely associated with skin melanogenesis in the chicken. These findings provide new clues to the molecular mechanism of melanin formation in the Muchuan black-boned chicken.

Autophagy attenuates copper-induced mitochondrial dysfunction by regulating oxidative stress in chicken hepatocytes

Copper (Cu) is an essential trace element that is required for the catalysis of several cellular enzymes. Excessive Cu could induce hepatotoxicity in humans and multiple animals. The purpose of this study was to investigate the effects of autophagy machinery on Cu-induced hepatotoxicity. Chicken hepatocytes were cultured in medium in the absence and presence of Cu sulfate (CuSO₄) (0, 10, 50, and 100 μM) for 0, 6, 12, and 24 h, and in the combination of CuSO₄ and N-acetyl-l-cysteine (NAC) (1 mM), rapamycin (10 nM), and 3-methyladenine (3-MA) (5 mM) for 24 h. Results showed that Cu could markedly increase the number of autophagosomes and LC3 puncta, induce autophagy-related genes (Beclin1, ATG5, LC3Ⅰ, LC3Ⅱ, mTOR, and Dynein) mRNA expression and proteins (BECN1, LC3Ⅱ/LC3Ⅰ) expression. NAC could relieve Cu-induced the changes of above genes and proteins. Additionally, rapamycin attenuated Cu-induced the increased lactic dehydrogenase (LDH), aspartate amino transferase (AST), and alanine aminotransferase (ALT) activities, and SOD-1 mRNA expression as well as the decreased cell viability, reactive oxygen species (ROS), hydrogen peroxide, total superoxide dismutase (T-SOD), malonaldehyde (MDA), catalase (CAT), HO-1 mRNA expression, adenosine triphosphate (ATP) levels, mitochondrial mass, and mitochondria membrane potential (MMP). But 3-MA had the opposite effects on above factors. Collectively, these findings provide strong evidence that Cu could induce autophagy by generating excessive ROS in hepatocytes, and autophagy might attenuate Cu-induced mitochondrial dysfunction by regulating oxidative stress.

Depth of field extension and objective space depth measurement based on wavefront imaging

When all the parts of the wavefront imaging system are kept static after wavefront measuring, the target's images are blurry, because the depth of field (DOF) of the system affects the imaging quality. In this paper, the method for extending the DOF of the wavefront imaging system through an integrated architecture of a liquid-crystal microlens array (LCMLA) powered by electricity and a common photosensitive array, is presented. The DOF can be extended remarkably only by stitching together several sub-images of the LCMLA. The problem that the wavefronts and imaging results are insensitive to the objective depth is also solved. Optimal driving voltage signals are found out according to Sobel mean gradient to efficiently calibrate the depth of objective space in order to quantitatively measure the depth. The approach indicates a viable way to effectively extend the DOF of imaging micro-systems and to measure the geometrical depth of targets at the same time.

An OLTAM system for analysis of brown/beige fat thermogenic activity

BACKGROUND/OBJECTIVES

Thermogenic fat is present in humans and emerging evidence indicates that increasing the content and activity of these adipocytes may lead to weight loss and improved metabolic health. Multiple reporter systems have been developed to assay thermogenic fat activity based on the transcriptional and translational activation of Ucp1, the key molecule that mediates nonshivering thermogenesis. Our study aims to develop a much-needed tool to monitor thermogenic fat activity through a mechanism independent of Ucp1 regulation, therefore effectively assaying not only canonical β-adrenergic activation but also various non-UCP1-mediated thermogenic pathways that have been increasingly appreciated.

METHODS

We detected increased luciferase activity upon thermogenic activation in interscapular brown and inguinal subcutaneous fat in ODD-Luc mice, a hypoxia reporter mouse model. We then developed an OLTAM (ODD-Luc based Thermogenic Activity Measurement) system to assay thermogenic fat cell activity.

RESULTS

In both primary murine and human adipocytes and an immortalized adipose cell line that were transduced with the OLTAM system, luciferase activity can be readily measured and visualized by bioluminescence imaging in response to a variety of stimuli, including UCP1-independent thermogenic signaling. This system can offer a convenient method to assay thermogenic activity for both basic and translational research.

CONCLUSIONS

The OLTAM system offers a convenient way to measure of the activation of thermogenic fat and presents opportunities to discover novel signaling pathways and unknown compounds targeting metabolically active adipocytes to counteract human obesity.

Efficacy and safety of three adefovir-based combination therapies in HBeAg-positive chronic hepatitis B patients with suboptimal response to adefovir monotherapy

Although high potent nucleos(t)ide analogues are strongly recommended as first-line therapy for chronic hepatitis B (CHB) in China, some patients are still being treated with adefovir disoproxil (ADV), especially those low-income patients whose health insurance could not reimburse the drug cost. Therefore, the management of patients who have failed ADV therapy or who sustained renal damage during ADV therapy remains an important clinical problem in China. This retrospective study aimed to compare the efficacy and safety of lamivudine (LAM), telbivudine (LdT) or entecavir (ETV) add-on strategies to optimize the treatment of patients with prior suboptimal response to ADV monotherapy. A total of 277 eligible patients were included in this study, and the baseline characteristics were similar among the LAM + ADV (n = 116), LdT + ADV (n = 72) and ETV + ADV (n = 89) groups. At week 96, both the proportion of undetectable HBV DNA (81.03% for LAM + ADV, 84.72% for LdT + ADV and 88.76% for ETV + ADV; P = .317) and ALT elevation (5.17% for LAM + ADV, 4.17% for LdT + ADV and 4.49% for ETV + ADV; P = 1.000) were similar among the three groups; also, a significant decline in liver stiffness was observed in each group from baseline to week 96. At week 96, the rate of HBeAg seroconversion was significantly higher in LdT + ADV than in LAM + ADV (26.39% vs 13.79%, P = .031) and ETV + ADV (26.39% vs 10.11%, P = .007). During the 96 weeks, no obvious renal injury was reported in any of the three groups, but an improvement in eGFR was found in LdT + ADV compared with LAM + ADV and ETV + ADV. In summary, all three combination strategies provide good control of virus replication, but the LdT + ADV combination therapy may yield better HBeAg seroconversion and eGFR improvement.

Genetic variation in the MITF promoter affects skin colour and transcriptional activity in black-boned chickens

1. Microphthalmia-associated transcription factor (MITF) plays a pivotal role in melanocyte development by regulating the transcription of major pigmentation enzymes (e.g. TYR, TYRP1 and DCT). A single-nucleotide polymorphism (SNP), c.-638T>C, was identified in the MITF promoter, and genotyping of a population (n = 426) revealed that SNP c.-638T>C was associated with skin colour in black-boned chickens. 2. Individuals with genotypes CC and TC exhibited greater MTIF expression than those with genotype TT. Luciferase assays also revealed that genotype CC and TC promoters had higher activity levels than genotype TT. Expression of melanogenesis-related gene (TYR) was higher in the skin of chickens with the CC and CT genotype compared to TT chickens (P < 0.05). 3. Transcription factor-binding site analyses showed that the c.-638C allele contains a putative binding site for transcription factor sterol regulatory element-binding transcription factor 2, aryl hydrocarbon receptor nuclear translocator, transcription factor binding to IGHM enhancer 3 and upstream transcription factor 2. In contrast, the c.-638T allele contains binding sites for Sp3 transcription factor and Krüppel-like factor 1. 4. It was concluded that MITF promoter polymorphisms affected chicken skin colour. SNP c.-638T>C could be used for the marker-assisted selection of skin colour in black-boned chicken breeding.

Characterization of retroviral infectivity and superinfection resistance during retrovirus-mediated transduction of mammalian cells

Retroviral vectors including lentiviral vectors are commonly used tools to stably express transgenes or RNA molecules in mammalian cells. Their utilities are roughly divided into two categories, stable overexpression of transgenes and RNA molecules, which requires maximal transduction efficiency, or functional selection with retrovirus (RV)-based libraries, which takes advantage of retroviral superinfection resistance. However, the dynamic features of RV-mediated transduction are not well characterized. Here, we engineered two murine stem cell virus-based retroviral vectors expressing dual fluorescence proteins and antibiotic markers, and analyzed virion production efficiency and virion stability, dynamic infectivity and superinfection resistance in different cell types, and strategies to improve transduction efficiency. We found that the highest virion production occurred between 60 and 72 h after transfection. The stability of the collected virion supernatant decreased by >60% after 3 days in storage. We found that RV infectivity varied drastically in the tested human cancer lines, while low transduction efficiency was partially overcome with increased virus titer, prolonged infection duration and/or repeated infections. Furthermore, we demonstrated that RV receptors PIT1 and PIT2 were lowly expressed in the analyzed cells, and that PIT1 and/or PIT2 overexpression significantly improved transduction efficiency in certain cell lines. Thus, our findings provide resourceful information for the optimal conditions of retroviral-mediated gene delivery.

First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter with DAMIC at SNOLAB

We present direct detection constraints on the absorption of hidden-photon dark matter with particle masses in the range 1.2-30  eV c^{-2} with the DAMIC experiment at SNOLAB. Under the assumption that the local dark matter is entirely constituted of hidden photons, the sensitivity to the kinetic mixing parameter κ is competitive with constraints from solar emission, reaching a minimum value of 2.2×10^{-14} at 17  eV c^{-2}. These results are the most stringent direct detection constraints on hidden-photon dark matter in the galactic halo with masses 3-12  eV c^{-2} and the first demonstration of direct experimental sensitivity to ionization signals <12  eV from dark matter interactions.