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1.
Opt Express ; 29(3): 3795-3807, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33770972

RESUMO

With the novel capabilities of engineering the optical wavefront at the nanoscale, the dielectric metalens has been utilized for fluorescence microscopy imaging system. However, the main technical difficulty is how to realize the achromatic focusing and light modulation simultaneously by a single-layer metalens in the two-photon excitation STED (TPE-STED) endomicroscopy imaging system. Herein, by combining the spatial multiplexing technology and vortex phase modulation, a single-layer multitasking vortex-metalens as a miniature microscopy objective on the end of fiber was proposed. The multitasking vortex-metalens with 36-sectors interleaving (diameter of 100 µm) could focus the excitation beam (1050 nm) and depletion beam (599 nm) to the same focal distance, modulate a doughnut-shaped depletion spot with vortex phase and reshape the focal spots to further make improvement in the quality and symmetry. According to the TPE-STED theory, a symmetrical effective fluorescent spot with the lateral resolution of 30 nm was obtained by the proposed metalens. Thus, with the advantage of ultra-compact and lightweight, we prospect that the subminiature multitasking metalens will help guide future developments in high-performance metalenses toward high-resolution and real-time images for deep biological tissue in vivo and enable scientific high-end miniature endomicroscopy imaging system.

2.
Nanotechnology ; 2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33684903

RESUMO

Stimulus-triggered drug delivery systems (DDSs) based on lanthanide-doped upconversion nanoparticles (UCNPs) have attracted intensive attention for treating cancers due to the merits of high drug availability, precisely controlled drug release, and low side-effects. However, such DDSs usually exhibit a single stimulus-response, which may limit the efficiency of cancer treatment. To extend response types in a single DDS, we construct NaYF4:Yb/Tm@SiO2- doxorubicin (Dox)/curcumin (Cur)-chitosan (CS)/2-Octen-1-ylsuccinic anhydride (OSA) nanoparticles with core-shell structures. Our method is based on the exploration of a synergistic effect of UCNPs and multiple drugs. To be specific, the NaYF4:Yb/Tm is used to convert near-infrared light to visible light, activating Cur photosensitizers to produce singlet oxygen for photodynamic therapy, while CS/OSA responds to a low pH environment to release cancer drugs including Dox and Cur for chemotherapy through breaking a free carboxyl group. The results show that the UCNPs with 40-nm diameter, 23-nm-thick mesoporous SiO2, and 19/1 mol% Yb3+/Tm3+concentrations could continuously release Dox and Cur at a pH value of 6.5 within 6 hours after the excitation of a 980-nm-wavelength laser. Our study provides a promising approach for developing efficient DDSs for cancer treatment.

3.
New Phytol ; 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33629353

RESUMO

Drought is one of the primary abiotic stresses, seriously implicating plant growth and productivity. Stomata play a crucial role in regulating drought tolerance. However, the molecular mechanism on stomatal movement-mediated drought tolerance remains unclear. Using genetic, molecular and biochemical techniques, we identified that the PdGNC directly activating the promoter of PdHXK1 by binding the GATC element, a hexokinase (HXK) synthesis key gene. Here, PdGNC, a member of the GATA transcription factor family, was greatly induced by abscisic acid and dehydration. Overexpressing PdGNC in poplar (Populus clone 717) resulted in reduced stomatal aperture with greater water-use efficiency and increased water deficit tolerance. By contrast, CRISPR/Cas9-mediated poplar mutant gnc exhibited increased stomatal aperture and water loss with reducing drought resistance. PdGNC activates PdHXK1 (a hexokinase synthesis key gene), resulting in a remarkable increase in hexokinase activity in poplars subjected to water deficit. Furthermore, hexokinase promoted nitric oxide (NO) and hydrogen peroxide (H2 O2 ) production in guard cells, which ultimately reduced stomatal aperture and increased drought resistance. Together, PdGNC confers drought stress tolerance by reducing stomatal aperture caused by NO and H2 O2 production via the direct regulation of PdHXK1 expression in poplars.

4.
Transbound Emerg Dis ; 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33559368

RESUMO

The variety and widespread of coronavirus in natural reservoir animals is likely to cause epidemics via interspecific transmission, which has attracted much attention due to frequent coronavirus epidemics in recent decades. Birds are natural reservoir of various viruses, but the existence of coronaviruses in wild birds in central China has been barely studied. Some bird coronaviruses belongs to the genus of Deltacoronavirus. To explore the diversity of bird deltacoronaviruses in central China, we tested fecal samples from 415 wild birds in Hunan Province, China. By RT-PCR detection, we identified eight samples positive for deltacoronaviruses which were all from common magpies, and in four of them, we successfully amplified complete deltacoronavirus genomes distinct from currently known deltacoronavirus, indicating four novel deltacoronavirus stains (HNU1-1, HNU1-2, HNU2 and HNU3) . Comparative analysis on the four genomic sequences showed that these novel magpie deltacoronaviruses shared three different S genes among which the S genes of HNU1-1 and HNU1-2 showed 93.8% amino acid (aa) identity to that of thrush coronavirus HKU12, HNU2 S showed 71.9% aa identity to that of White-eye coronavirus HKU16, and HKU3 S showed 72.4% aa identity to that of sparrow coronavirus HKU17. Recombination analysis showed that frequent recombination events of the S genes occurred among these deltacoronavirus strains. Two novel putative cleavage sites separating the nonstructural proteins in the HNU coronaviruses were found. Bayesian phylogeographic analysis showed that the south coast of China might be a potential origin of bird deltacoronaviruses existing in inland China. In summary, these results suggest that common magpie in China carries diverse deltacoronaviruses with novel genomic features, indicating an important source of environmental coronaviruses closed to human communities, which may provide key information for prevention and control of future coronavirus epidemics.

5.
Endocr Connect ; 10(3): 325-335, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33617465

RESUMO

Exercise has been recommended as an important strategy to improve glucose metabolism in obesity. Adipose tissue fibrosis is associated with inflammation and is implicated in glucose metabolism disturbance and insulin resistance in obesity. However, the effect of exercise on the progression of adipose tissue fibrosis is still unknown. The aim of the present study was to investigate whether exercise retarded the progression of adipose tissue fibrosis and ameliorated glucose homeostasis in diet-induced obese mice. To do so, obesity and adipose tissue fibrosis in mice were induced by high-fat diet feeding for 12 weeks and the mice subsequently received high-fat diet and exercise intervention for another 12 weeks. Exercise alleviated high-fat diet-induced glucose intolerance and insulin resistance. Continued high-fat diet feeding exacerbated collagen deposition and further increased fibrosis-related gene expression in adipose tissue. Exercise attenuated or reversed these changes. Additionally, PPARγ, which has been shown to inhibit adipose tissue fibrosis, was observed to be increased following exercise. Moreover, exercise decreased the expression of HIF-1α in adipose fibrosis, and adipose tissue inflammation was inhibited. In conclusion, our data indicate that exercise attenuates and even reverses the progression of adipose tissue fibrosis, providing a plausible mechanism for its beneficial effects on glucose metabolism in obesity.

6.
Lab Invest ; 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33268842

RESUMO

NLRP3 inflammasome activation, which can be triggered by reactive oxygen species (ROS), contributes to nonalcoholic steatohepatitis (NASH) progression. Exercise is an effective therapeutic strategy for NASH. However, whether exercise prevents NLRP3 activation in NASH has not been investigated. Here, we investigated the effect of exercise on NLRP3 inflammasome in mice with high-fat diet (HFD)-induced or methionine and choine-deficient (MCD) diet-induced NASH and explored whether adropin, a metabolic peptide hormone shown to inhibit inflammation, mediates an exercise-induced benefit against NLRP3 inflammasome activation. Exercise alleviated diet-induced hepatic steatosis, inflammation, and fibrosis. Importantly, exercise significantly reduced the expression of NLRP3 inflammasome components, decreased Caspase-1 enzymatic activity, normalized IL-1ß production, and suppressed ROS overproduction in HFD-fed and MCD diet-fed mice. The exercise-elicited NLRP3 inflammasome inhibition was accompanied by increased adropin levels. Moreover, serum adropin levels were negatively correlated with serum IL-1ß levels. We further explored the effect of adropin on the NLRP3 inflammasome in palmitic acid (PA)-treated hepatocytes and Kupffer cells. Although adropin treatment did not significantly decrease the levels of all inflammasome components, it reduced the active Caspase-1 level, decreased Caspase-1 activity and downregulated IL-1ß expression in hepatocytes and Kupffer cells (KCs) treated with PA. Moreover, ROS levels in PA-stimulated hepatocytes and Kupffer cells were reduced upon adropin treatment. In summary, we demonstrated that the inhibitory effect of exercise on NLRP3 inflammasome activation was associated with adropin induction, resulting in NASH improvement.

8.
Huan Jing Ke Xue ; 41(12): 5381-5388, 2020 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-33374054

RESUMO

Based on the seasonal changes in the nitrogen and phosphorus concentrations in Hanfeng Lake from March 2017 to February 2018, the nutrient limitation status was evaluated by the stoichiometric molar ratio of nitrogen and phosphorus. The results showed that the average concentrations of TN, DN, and NO3--N were 1.60, 1.25, and 0.91 mg·L-1 in Hanfeng Lake, respectively. The seasonal changes of those indicators were similar, showing the highest concentration in winter and lowest in summer. NO3--N accounted for TN significantly in the water body, and the concentrations of NH4+-N and NO2--N remained at low levels and changed steadily. The average concentrations of TP, DP, and PO43--P were 0.13, 0.09, and 0.06 mg·L-1, respectively. The changes in the concentrations of TP and DP were similar, showing a trend of increasing in spring and summer, and then decreasing in autumn and winter, while the PO43--P concentration showed the trend of fluctuated decrease. TN/TP varied from 11.07 to 56.02, with an average value of 29.23. TN/TP changed seasonally, with the highest value occurring in winter and the lowest value in summer. The conditions of the water body were conducive to growth and reproduction of algae for most of the time during sampling months. The water body was occasionally nitrogen limited and rarely phosphorus limited. The seasonal variation in TN/TP ratio was affected by several factors such as rainfall runoff, fertilizer use, sewage discharge, and aquatic biological activities. Further, protection strategies were proposed for the improvement of the water body in terms of present water quality characteristics in Hanfeng Lake.

9.
Pak J Pharm Sci ; 33(3): 953-960, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33191218

RESUMO

Atractylodis rhizoma is a frequently-used traditional Chinese medicine in clinical practice, which have the effect of eliminating dampness and tonifying spleen. And after being processed with wheat bran, the dryness of A. rhizoma is reduced, and the function of tonifying spleen is enhanced. Atractylenolides are the major bioactive components of A. rhizoma, including atractylenolide I (AI), atractylenolide Ⅱ (AⅡ) and atractylenolide Ⅲ (AⅢ). The present study aimed to develope a new UPLC-MS/MS method for simultaneous quantification of three atractylenolides in rat urine, and applied to the excretory kinetics in Sprague-Dawley rats after oral administration of crude and processed A. rhizoma extracts. Analytes and internal standard were detected without interference in the multiple reaction monitoring (MRM) mode with positive electrospray ionization. The excretory kinetics parameters were calculated by a urine drug analysis model of drug and statistics (DAS) 3.2.8 software. The t1/2 and Ke of three atractylenolides had no significant difference between crude and processed A. rhizoma, but the recovery accumulative excretion of them in processed A. rhizoma were apparently higher than the crude ones (p<0.05, p<0.01). The results showed that only a small amount of atractylenolides excreted in urine and processing A. rhizoma with wheat bran by stir frying could promote the urinary excretion of them.

10.
New Phytol ; 2020 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-33091182

RESUMO

Heat-stressed Arabidopsis plants release heterochromatin-associated transposable element (TE) silencing, yet it is not accompanied by major reductions of epigenetic repressive modifications. In this study, we explored the functional role of histone H1 in repressing heterochromatic TEs in response to heat stress. We generated and analyzed RNA and bisulfite-sequencing data of wild-type and h1 mutant seedlings before and after heat stress. Loss of H1 caused activation of pericentromeric Gypsy elements upon heat treatment, despite these elements remaining highly methylated. By contrast, nonpericentromeric Copia elements became activated concomitantly with loss of DNA methylation. The same Copia elements became activated in heat-treated chromomethylase 2 (cmt2) mutants, indicating that H1 represses Copia elements through maintaining DNA methylation under heat. We discovered that H1 is required for TE repression in response to heat stress, but its functional role differs depending on TE location. Strikingly, H1-deficient plants treated with the DNA methyltransferase inhibitor zebularine were highly tolerant to heat stress, suggesting that both H1 and DNA methylation redundantly suppress the plant response to heat stress.

11.
Biomed Opt Express ; 11(8): 4408-4418, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32923052

RESUMO

With the advantages of completely controlling the phase, amplitude, and polarization in subwavelength range, metalenses have drawn intensive attentions in high resolution two-photon micro-endoscopic fluorescence imaging system. However, chromatic dispersion and severe scattering of biological tissue significantly reduce excitation-collection efficiency in the traditional two-photon imaging system based on traditional metalenses designed in the air background. Here, an excitation and emission dual-wavelength confocal and polarization-insensitive metalens designed in the biological tissue environment was proposed by adopting the composite embedding structure and spatial multiplexing approach. The metalens with numerical aperture (NA) of 0.895 can focus the excitation (915 nm) and emission (510 nm) beams to the same focal spot in the mouse cortex. According to the theoretical simulation of two-photon fluorescence imaging, the lateral resolution of the collected fluorescent spots via the proposed metalens can be up to 0.42 µm. Compared to the metalens designed in the air environment, the collection efficiency of fluorescent spot is improved from 5.92% to 14.60%. Our investigation has opened a new window of high resolution and minimally invasive imaging in deep regions of biological tissues.

12.
JCI Insight ; 5(17)2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32780726

RESUMO

New strategies are needed to enhance the efficacy of anti-programmed cell death protein antibody (anti-PD-1 Ab) in cancer. Here, we report that inhibiting palmitoyl-protein thioesterase 1 (PPT1), a target of chloroquine derivatives like hydroxychloroquine (HCQ), enhances the antitumor efficacy of anti-PD-1 Ab in melanoma. The combination resulted in tumor growth impairment and improved survival in mouse models. Genetic suppression of core autophagy genes, but not Ppt1, in cancer cells reduced priming and cytotoxic capacity of primed T cells. Exposure of antigen-primed T cells to macrophage-conditioned medium derived from macrophages treated with PPT1 inhibitors enhanced melanoma-specific killing. Genetic or chemical Ppt1 inhibition resulted in M2 to M1 phenotype switching in macrophages. The combination was associated with a reduction in myeloid-derived suppressor cells in the tumor. Ppt1 inhibition by HCQ, or DC661, induced cyclic GMP-AMP synthase/stimulator of interferon genes/TANK binding kinase 1 pathway activation and the secretion of interferon-ß in macrophages, the latter being a key component for augmented T cell-mediated cytotoxicity. Genetic Ppt1 inhibition produced similar findings. These data provide the rationale for this combination in melanoma clinical trials and further investigation in other cancers.

13.
Genome Biol ; 21(1): 144, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32546254

RESUMO

BACKGROUND: Stable gene repression is essential for normal growth and development. Polycomb repressive complexes 1 and 2 (PRC1&2) are involved in this process by establishing monoubiquitination of histone 2A (H2Aub1) and subsequent trimethylation of lysine 27 of histone 3 (H3K27me3). Previous work proposed that H2Aub1 removal by the ubiquitin-specific proteases 12 and 13 (UBP12 and UBP13) is part of the repressive PRC1&2 system, but its functional role remains elusive. RESULTS: We show that UBP12 and UBP13 work together with PRC1, PRC2, and EMF1 to repress genes involved in stimulus response. We find that PRC1-mediated H2Aub1 is associated with gene responsiveness, and its repressive function requires PRC2 recruitment. We further show that the requirement of PRC1 for PRC2 recruitment depends on the initial expression status of genes. Lastly, we demonstrate that removal of H2Aub1 by UBP12/13 prevents loss of H3K27me3, consistent with our finding that the H3K27me3 demethylase REF6 is positively associated with H2Aub1. CONCLUSIONS: Our data allow us to propose a model in which deposition of H2Aub1 permits genes to switch between repression and activation by H3K27me3 deposition and removal. Removal of H2Aub1 by UBP12/13 is required to achieve stable PRC2-mediated repression.

14.
Dev Comp Immunol ; 110: 103727, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32387471

RESUMO

Adiponectin receptors (AdipoRs) comprise a seven-transmembrane domain-containing protein family, which specifically recognize adiponectin (APN) and play critical roles in the immunological and physiological processes in vertebrates. In the present study, a novel AdipoR is identified from oyster Crassostrea gigas (designated as CgAdipoR). The full-length cDNA of CgAdipoR is of 1209 bp encoding a polypeptide of 343 amino acids. There is an N-terminal domain, a Hly III domain, and a C-terminal domain in CgAdipoR. After the transfection of CgAdipoR, the level of intracellular Ca2+ into HEK293T cells increases significantly (1.36-fold, p < 0.05) after APN incubation. The mRNA transcripts of CgAdipoR are widely distributed in all the tested tissues, with the highest expression level in haemocytes (3.20-fold of that in hepatopancreas, p < 0.05). After lipopolysaccharide (LPS), Vibrio splendidus and polyinosinic-polycytidylic acid (poly (I:C)) stimulations, the mRNA expression of CgAdipoR in haemocytes is significantly up-regulated and reached the highest level at 24 h (15.07-fold, p < 0.01), 6 h (4.39-fold, p < 0.01) and 24 h (5.62-fold, p < 0.01) compared to control group, respectively. After CgAdipoR is interfered by specific CgAdipoR-dsRNA, the expression level of interleukins (CgIL17-1, CgIL17-2, CgIL17-3 and CgIL17-5) in haemocytes decreases significantly (p < 0.01) at 24 h post LPS stimulation, while the expression level of CgTNF-1 increases significantly (1.68-fold, p < 0.01), compared to that in the dsEGFP group. In CgAdipoR dsRNA-injected oysters, the mRNA expressions of anti-apoptotic B-cell lymphoma-2 (Bcl-2) in haemocytes significantly decreases at 24 h after LPS challenge, which is (0.58-fold, p < 0.05) of that in dsEGFP-injected oysters, while the apoptotic rate of haemocytes is significantly up-regulated (1.93-fold of that in dsEGFP group, p < 0.05). These results collectively suggest that CgAdipoR plays an important role in the immune response of oysters by regulating the expressions of inflammatory cytokines and haemocyte apoptosis.

15.
Virol Sin ; 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32236817

RESUMO

Porcine adenoviruses (PAdVs) are classified into three species, PAdV-A, PAdV-B, and PAdV-C. The genomes of PAdV-A and PAdV-C have been well characterized. However, the genome of PAdV-B has never been completely sequenced, and the epidemiology of PAdV-B remains unclear. In our study, we have identified a novel strain of PAdV-B, named PAdV-B-HNU1, in porcine samples collected in China by viral metagenomic assay and general PCR. The genome of PAdV-B-HNU1 is 31,743 bp in length and highly similar to that of California sea lion adenovirus 1 (C. sea lion AdV-1), which contains typical mastadenoviral structures and some unique regions at the carboxy-terminal end. Especially, PAdV-B-HNU1 harbors a dUTPase coding region not clustering with other mastadenoviruses except for C. sea lion AdV-1 and a fiber coding region homologous with galectin 4 and 9 of animals. However, the variance of GC contents between PAdV-B-HNU1 (55%) and C. sea lion AdV-1 (36%) indicates their differential evolutionary paths. Further epidemiologic study revealed a high positive rate (51.7%) of PAdV-B-HNU1 in porcine lymph samples, but low positive rates of 10.2% and 16.1% in oral swabs and rectal swabs, respectively. In conclusion, this study characterized a novel representative genome of a lymphotropic PAdV-B with unique evolutionary origin, which contributes to the taxonomical and pathogenic studies of PAdVs.

16.
Fish Shellfish Immunol ; 99: 442-451, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32084540

RESUMO

The homeostasis of immune cells during immune response is vital for hosts to defend against invaders. Activating transcription factor 6 (ATF6) is an important transcription factor in the unfolded protein response (UPR) to maintaining cellular homeostasis. In the present study, one ATF6 homologue was identified from Pacific oyster Crassostrea gigas (designated as CgATF6ß). The full length cDNA of CgATF6ß was of 2645 bp with a 1596 bp open reading frame (ORF) encoding a polypeptide of 531 amino acids. The deduced amino acid sequence of CgATF6ß was predicted to contain a transmembrane region, a conserved basic leucine zipper (bZIP) domain, a site 1 protease cleavage site, a site 2 protease cleavage site, and a Golgi localization signal. CgATF6ß mRNA was constitutively expressed in hemocytes, gill, mantle, gonad, hepatopancreas and labial palp, with a slightly higher expression level in muscle (2.45-fold of that in gill, p < 0.05). After oysters were challenged with Vibrio splendidus, the mRNA expression levels of CgATF6ß in hemocytes were significantly up-regulated at 3 h (2.68-fold of that in seawater group, p < 0.01) and peaked at 12 h (3.14-fold of that in seawater group, p < 0.01). The endogenic CgATF6ß protein was mainly located in the cytoplasm of oyster hemocytes, and it was significantly transported into the nuclei of hemocytes at 1.5 h after the challenge with V. splendidus. After an injection with CgATF6ß dsRNA, the mRNA expression of CgATF6ß was knocked down to 0.26-fold of that in dsGFP group (p < 0.01). In CgATF6ß dsRNA-injected oysters, the mRNA expressions of glucose-regulated protein 78 (GRP78), calnexin (CNX) and anti-apoptotic B-cell lymphoma-2 (Bcl-2) in hemocytes were significantly decreased at 12 h after V. splendidus challenge, which were 0.65-fold (p < 0.01), 0.54-fold (p < 0.01) and 0.17-fold (p < 0.01) of that in dsGFP-injected oysters, while the apoptotic rate of hemocytes was significantly up-regulated (1.97-fold of that in dsGFP group, p < 0.05). Collectively, these results suggested that CgATF6ß was involved in apoptosis inhibition of oyster hemocytes upon V. splendidus challenge by regulating the expression of CgGRP78, CgCNX and CgBcl-2.


Assuntos
Fator 6 Ativador da Transcrição/imunologia , Apoptose , Crassostrea/imunologia , Hemócitos/imunologia , Vibrioses/veterinária , Fator 6 Ativador da Transcrição/genética , Animais , Clonagem Molecular , Crassostrea/genética , DNA Complementar/genética , Regulação da Expressão Gênica , Hemócitos/citologia , Homeostase , Imunidade Inata , Fases de Leitura Aberta , RNA Mensageiro/genética , Resposta a Proteínas não Dobradas , Vibrio , Vibrioses/imunologia
17.
Artigo em Inglês | MEDLINE | ID: mdl-32106644

RESUMO

Objective: The purpose of this experiment was to investigate the effects of the Agaricus bisporus stem residue (ABSR) on the performance, nutrients digestibility, antioxidant activity of laying hens, and its effects on egg storage to determine the appropriate dosage of ABSR, so as to provide a scientific basis for the effective utilization of ABSR. Methods: A total of 384 53-wk-old Nongda Ⅲ layers were randomly divided into six treatments, four replicates in each treatment and 16 birds in each replicate. The control treatment was fed with basic diet, while experimental treatments were fed with diets of 2%, 4%, 6%, 8%, and 10% ABSR respectively. The experimental period was 56 d. Results: The results showed that compared with the control treatment, ABSR had no significant effect on laying performance (p>0.05). The crude protein and total energy digestibility of experimental treatments was significantly higher than those of control treatment (p<0.05). When eggs were stored for 1 wk, 2 wk, and 3 wk at 25℃, there were no significant differences in egg storage between the experimental treatments and the control treatment (p>0.05). The superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity in the serum of the experimental treatments were significantly higher than those of the control treatment (p<0.05), and the malonaldehyde (MDA) content did not change dramatically. SOD activity in yolk of experimental treatments was significantly higher than that in control treatment (p<0.05); MDA content in yolk was markedly lower than that in control treatment (p<0.05). The activity of GSH-Px and SOD in yolk of experimental treatments was significantly higher than that of control treatment stored at 25℃ for 21 d, and the content of MDA was significantly lower than that of control treatment (p<0.05). Conclusion: ABSR can be used to improve the antioxidant activity of laying hens without affecting laying performance.

18.
Fish Shellfish Immunol ; 95: 584-594, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31678182

RESUMO

Dicer, as a member of ribonuclease III family, functions in RNA interference (RNAi) pathway to direct sequence-specific degradation of cognate mRNA. It plays important roles in antiviral immunity and production of microRNAs. In the present study, a Dicer gene was identified from oyster Crassostrea gigas, and its open reading frame (ORF) encoded a polypeptide (designed as CgDicer) of 1873 amino acids containing two conserved ribonuclease III domains (RIBOc) and a double-stranded RNA-binding motif (DSRM). The deduced amino acid sequence of CgDicer shared identities ranging from 18.5% to 46.6% with that of other identified Dicers. The mRNA transcripts of CgDicer were detectable in all the examined tissues of adult oysters, with the highest expression in hemocytes (11.21 ±â€¯1.64 fold of that in mantle, p < 0.05). The mRNA expression level of CgDicer in hemocytes was significantly up-regulated (36.70 ±â€¯11.10 fold, p < 0.01) after the oysters were treated with double-stranded RNA (dsRNA). In the primarily cultured oyster hemocytes, the mRNA transcripts of CgDicer were significantly induced at 12 h after the stimulation with poly(I:C), which were 2.04-fold (p < 0.05) higher than that in control group. Immunocytochemistry assay revealed that CgDicer proteins were mainly distributed in the cytoplasm of hemocytes. The two most important functional domains of CgDicer, DSRM and RIBOc, were recombinant expressed in Escherichia coli transetta (DE3), and the recombinant DSRM protein displayed significantly binding activity to dsRNA and poly(I:C) in vitro, while the recombinant RIBOc protein exhibited significantly dsRNase activity to cleave dsRNA in vitro. These results collectively suggested that CgDicer functioned as either an intracellular recognition molecule to bind dsRNA or an effector with ribonuclease activity, which might play a crucial role in anti-viral immunity of oyster.


Assuntos
Crassostrea/enzimologia , Crassostrea/imunologia , Imunidade Inata , Ribonuclease III/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Células Cultivadas , Crassostrea/genética , Perfilação da Expressão Gênica , Hemócitos/efeitos dos fármacos , Hemócitos/imunologia , Filogenia , Poli I-C/farmacologia , RNA Mensageiro , Ribonuclease III/genética , Alinhamento de Sequência , Viroses/imunologia , Viroses/veterinária
19.
Arch Virol ; 164(12): 3151-3155, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31616994

RESUMO

Astroviruses (AstVs) have a very wide range of hosts and are associated with enteric and extra-enteric disease in mammals and birds. Cross-species transmission of AstVs has been observed frequently. In the present study, the genome of a novel astrovirus from Amur tigers (Panthera tigris) from a zoo in China was characterized and was found to have the typical genomic features of other mammal AstVs. It showed the highest nucleotide sequence similarity (46.1-87.3% identity) to AstVs from cats, indicating a close phylogenetic relationship and possible cross-species transmission between them. To our knowledge, this is the first identification and characterization of AstV from tigers, and this virus is the third astrovirus identified in hosts of the family Felidae. The results of this study will be helpful for understanding the origin, genetic diversity, and cross-species transmission of AstV.


Assuntos
Animais de Zoológico/virologia , Infecções por Astroviridae/veterinária , Astroviridae/isolamento & purificação , Tigres/virologia , Animais , Astroviridae/classificação , Astroviridae/genética , Infecções por Astroviridae/virologia , Gatos , China , Fezes/virologia , Filogenia , Análise de Sequência de DNA
20.
Front Cell Neurosci ; 13: 400, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31555097

RESUMO

Anodal-transcranial pulsed current stimulation (a-tPCS) has been used in human studies to modulate cortical excitability or improve behavioral performance in recent years. Multiple studies show crucial roles of astrocytes in cortical plasticity. The calcium activity in astrocytes could regulate synaptic transmission and synaptic plasticity. Whether the astrocytic activity is involved in a-tPCS-induced cortical plasticity is presently unknown. The purpose of this study is to investigate the calcium responses in neurons and astrocytes evoked by a-tPCS with different current intensities, and thereby provides some indication of the mechanisms underlying a-tPCS-induced cortical plasticity. Two-photon calcium imaging was used to record the calcium responses of neurons and astrocytes in mouse somatosensory cortex. Local field potential (LFP) evoked by sensory stimulation was used to assess the effects of a-tPCS on plasticity. We found that long-duration a-tPCS with high-intensity current could evoke large-amplitude calcium responses in both neurons and astrocytes, whereas long-duration a-tPCS with low-intensity current evoked large-amplitude calcium responses only in astrocytes. The astrocytic Ca2+ elevations are driven by noradrenergic-dependent activation of the alpha-1 adrenergic receptors (A1ARs), while the intense Ca2+ responses of neurons are driven by action potentials. LFP recordings demonstrated that low-intensity a-tPCS led to enhancement of cortical excitability while high-intensity a-tPCS resulted in diminution of cortical excitability. The results provide some evidence that the enhancement of a-tPCS-induced cortical excitability might be partly associated with calcium elevation in astrocytes, whereas the diminution of a-tPCS-induced cortical excitability might be caused by excessive calcium activity in neurons. These findings indicate that the appropriate current intensity should be used in the application of a-tPCS.

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