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1.
J Cell Biol ; 220(9)2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34228783

RESUMO

Expansion microscopy (ExM) increases the effective resolving power of any microscope by expanding the sample with swellable hydrogel. Since its invention, ExM has been successfully applied to a wide range of cell, tissue, and animal samples. Still, fluorescence signal loss during polymerization and digestion limits molecular-scale imaging using ExM. Here, we report the development of label-retention ExM (LR-ExM) with a set of trifunctional anchors that not only prevent signal loss but also enable high-efficiency labeling using SNAP and CLIP tags. We have demonstrated multicolor LR-ExM for a variety of subcellular structures. Combining LR-ExM with superresolution stochastic optical reconstruction microscopy (STORM), we have achieved molecular resolution in the visualization of polyhedral lattice of clathrin-coated pits in situ.

2.
Huan Jing Ke Xue ; 42(7): 3281-3290, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212654

RESUMO

In this study, indoor simulation experiments were performed to elucidate the effects of migration and transformation of dissolving organic matter (DOM) during the decay of algal blooms. Based on ultraviolet-visible spectra (UV-vis) and excitation-emission matrix spectroscopy (EEMs), spectral characterizations of dissolved organic matter (DOM) in overlying water were evaluated with analyses of the physical and chemical indexes, variation in dissolved organic carbon (DOC), and variation in dissolved inorganic carbon (DIC). Results showed that at the early stage of decay, a large amount of organic matter was released, and dissolved oxygen (DO) decreased sharply. With the extension of reaction time, DOC gradually changed into DIC, which further changed the oxidation-reduction and acid-base characteristics of the water. UV-vis spectra showed that a large amount of DOM was released with high aromaticity and a high degree of humification, and the released DOM was gradually degraded. With the application of parallel factor analysis in excitation-emission matrix spectroscopy (EEM-PARAFAC), three fluorescence components were analyzed:refractory humic-like substances (C1), protein-like tryptophan substances (C2) produced by algae, and fulvic-like substances (C3) related to microbial activities. Most protein-like tryptophan substances were degraded into fulvic-like substances by microorganisms during the decaying process. Heterotrophic microorganisms promoted the release of algae-derived DOM and accelerated the degradation of DOM. The DOM born during algae blooms decaying process was eventually converted into humic-like substance, which was difficult to be degraded. We analyzed correlations of water quality, UV-vis spectrum, and EEMs parameters. Results showed that ORP was positively correlated (P<0.05) with DO. There was a significant negative correlation (P<0.05) between pH and DOC, which was consistent with the trend of the transformation to from DOC to DIC; C1 was positively correlated (P<0.05) with Fn355; and C2 was significantly positively correlated (P<0.05) with DOC and Fn280; C3 was positively correlated (P<0.05) with FI, BIX and ß:α. The variation trend of these spectral parameters was consistent with that of DOM components. In summary, with the analyses of water quality characteristics and spectral characteristics of DOM in overlying water during algae blooms decaying process, it was expected that our results could contribute to the further exploration of the dynamic migration and transformation of lake DOM and the changes of carbon cycling.


Assuntos
Substâncias Húmicas , Água , Eutrofização , Substâncias Húmicas/análise , Lagos , Espectrometria de Fluorescência
3.
Artigo em Inglês | MEDLINE | ID: mdl-34235851

RESUMO

The role of solution aggregates on the charge transport process of conjugated polymers in electronic devices has gained increasing attention; however, the correlation of the charge carrier mobilities in the solution aggregates and the solid-state films remains elusive. Herein, three polymers, FBDOPV-2T, FBDOPV-2F2T, and FBDOPV-4F2T, are designed and synthesized, and exhibit distinct aggregation behavior in solution. By combining contact-free ultrafast Terahertz (THz) spectroscopy and field-effect transistor measurements, we track the charge carrier mobility of the aggregates of these polymers from the solution to thin-film states. Remarkably, the mobility of three polymers is found to follow nearly the same trend (FBDOPV-2T > FBDOPV-2F2T > > FBDOPV-4F2T) in both solution and thin-film states. The quantitative mobility correlation indicates that the charge transport properties of solution aggregates play a critical role in determining the thin-film charge transport properties and final device performance. Our results highlight the importance of investigating and controlling solution aggregation structures towards efficient organic electronic devices.

4.
Huan Jing Ke Xue ; 42(7): 3555-3564, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212682

RESUMO

The spatial distribution of fertilization intensity and its influencing factors are significant for the accurate management of fertilization and pollution prevention and control. Previous studies are mostly limited to the discussion of human factors that influences the spatial distribution of fertilization intensity while ignoring natural geographical factors. Based on the chemical fertilizer survey data collected from 23492 sites in Chengdu Plain and combined with Geostatistics analysis and Geographic Information System (GIS) technology, the spatial distribution characteristics and influencing factors of average nitrogen and phosphorus fertilizer application intensity from 2010 to 2015 in this region were explored. The results show that:① the average annual application intensity of nitrogen and phosphorus fertilizer in the study area from 2010 to 2015 is generally in the low and medium risk intensity of 120-360 kg·hm-2 and 60-180 kg·hm-2. The high risk intensity is mainly distributed in the grain (fruit) and vegetable growing areas such as Pidu, Pengzhou, Shifang, Longquanyi and Jintang, while the relatively low value areas are mostly distributed in the south and northeast. ② the nugget coefficients of nitrogen and phosphorus fertilizer application intensities are 66.17% and 41.60%. Their spatial distribution is determined by structural and random factors, showing a moderate spatial autocorrelation. ③ both human and natural factors have significant effects on the application intensity of nitrogen and phosphorus fertilizer. The crop type (fine classification) can explain the spatial variation of nitrogen fertilizer and phosphorus fertilizer respectively by 12.90% and 25.10%, which is the main controlling factor affecting the spatial distribution of nitrogen and phosphorus application intensity; the importance of soil parent material is second only to the planting crop type, and the independent explanation ability of phosphorus application intensity is about 3.6 times higher than that of nitrogen application intensity. When the type of planting crop plays a decisive role, the soil parent material still deeply restricts and affects the spatial distribution of nitrogen and phosphorus fertilizer application intensity in the study area. Therefore, the comprehensive effects of planting crop types and soil parent materials should be considered in fertilization management and environmental risk analysis, and the effects of soil parent material should also be taken into account in the application of phosphate fertilizer.


Assuntos
Fertilizantes , Fósforo , Agricultura , China , Fertilizantes/análise , Nitrogênio/análise , Fósforo/análise , Solo
5.
Biomed Res Int ; 2021: 4970265, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34258262

RESUMO

Objectives: To evaluate the value of the whole volume apparent diffusion coefficient (ADC) histogram in distinguishing between benign and malignant breast lesions and differentiating different molecular subtypes of breast cancers and to assess the correlation between ADC histogram parameters and Ki-67 expression in breast cancers. Methods: The institutional review board approved this retrospective study. Between September 2016 and February 2019, 189 patients with 84 benign lesions and 105 breast cancers underwent magnetic resonance imaging (MRI). Volumetric ADC histograms were created by placing regions of interest (ROIs) on the whole lesion. The relationships between the ADC parameters and Ki-67 were analysed using Spearman's correlation analysis. Results: Of the 189 breast lesions included, there were significant differences in patient age (P < 0.001) and lesion size (P = 0.006) between the benign and malignant lesions. The results also demonstrated significant differences in all ADC histogram parameters between benign and malignant lesions (all P < 0.001). The median and mean ADC histogram parameters performed better than the other ADC histogram parameters (AUCs were 0.943 and 0.930, respectively). The receiver operating characteristic (ROC) analysis revealed that the 10th percentile ADC value and entropy could determine the human epidermal growth factor receptor 2 (HER-2) status (both P = 0.001) and estrogen receptor (ER)/progesterone receptor (PR) status (P = 0.020 and P = 0.041, respectively). Among all breast cancer lesions, 35 tumours in the low-proliferation group (Ki - 67 < 14%) and 70 tumours in the high-proliferation group (Ki - 67 ≥ 14) were analysed with ROC curves and correlation analyses. The ROC analysis revealed that entropy and skewness could determine the Ki-67 status (P = 0.007 and P < 0.001, respectively), and there were weak correlations between ADC entropy (r = 0.383) and skewness (r = 0.209) and the Ki-67 index. Conclusion: The volumetric ADC histogram could serve as an imaging marker to determine breast lesion characteristics and may be a supplemental method in predicting tumour proliferation in breast cancer.

6.
J Exp Psychol Hum Percept Perform ; 47(5): 689-703, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34264727

RESUMO

In a dynamic search task, participants were instructed to search for a visual target among various distractors. An auditory stimulus presented in synchrony with a color change of the visual target can improve the efficiency of the search, which is known as the pip-and-pop effect. Some researchers have suggested that the underlying mechanism of this effect is multisensory integration, while others have thought it is due to an oddball stimulation that attracts attention. Utilizing the eye movement technique, we conducted 3 experiments to investigate the pip-and-pop effect and its causes. In Experiment 1, we used a static search paradigm and controlled for the presence or absence of sound cues when the visual target was presented. It turned out that sound had no effect on a static search; that is, no pip-and-pop effect was found. In Experiment 2, we used a dynamic search paradigm in which the participants were instructed to search for vertical or horizontal line segments among various directional distractor segments and as the color of individual segments changed randomly during the stimulus presentation, with and without the sound cue. We found that the pip-and-pop effect was present. The irrelevant sound reduced the mean fixation number and expanded the mean saccade amplitude. In Experiment 3, we also used a dynamic search paradigm and controlled the frequency of synchronization between the sound and the target color change. There were 3 types of sound conditions: No-sound, 1-sound, and 2-sound. The results suggest that as the frequency of synchronization between the sound and the target color change increases (2-sound condition), the pip-and-pop effect also increases. Therefore, we propose that the pip-and-pop effect is more likely to result from the attention attracted by oddball stimuli than from the multisensory integration of synchronized auditory-visual stimuli. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

7.
Lancet Infect Dis ; 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: covidwho-1284631

RESUMO

BACKGROUND: A vaccine against SARS-CoV-2 for children and adolescents will play an important role in curbing the COVID-19 pandemic. Here we aimed to assess the safety, tolerability, and immunogenicity of a candidate COVID-19 vaccine, CoronaVac, containing inactivated SARS-CoV-2, in children and adolescents aged 3-17 years. METHODS: We did a double-blind, randomised, controlled, phase 1/2 clinical trial of CoronaVac in healthy children and adolescents aged 3-17 years old at Hebei Provincial Center for Disease Control and Prevention in Zanhuang (Hebei, China). Individuals with SARS-CoV-2 exposure or infection history were excluded. Vaccine (in 0·5 mL aluminum hydroxide adjuvant) or aluminum hydroxide only (alum only, control) was given by intramuscular injection in two doses (day 0 and day 28). We did a phase 1 trial in 72 participants with an age de-escalation in three groups and dose-escalation in two blocks (1·5 µg or 3·0 µg per injection). Within each block, participants were randomly assigned (3:1) by means of block randomisation to receive CoronaVac or alum only. In phase 2, participants were randomly assigned (2:2:1) by means of block randomisation to receive either CoronaVac at 1·5 µg or 3·0 µg per dose, or alum only. All participants, investigators, and laboratory staff were masked to group allocation. The primary safety endpoint was adverse reactions within 28 days after each injection in all participants who received at least one dose. The primary immunogenicity endpoint assessed in the per-protocol population was seroconversion rate of neutralising antibody to live SARS-CoV-2 at 28 days after the second injection. This study is ongoing and is registered with ClinicalTrials.gov, NCT04551547. FINDINGS: Between Oct 31, 2020, and Dec 2, 2020, 72 participants were enrolled in phase 1, and between Dec 12, 2020, and Dec 30, 2020, 480 participants were enrolled in phase 2. 550 participants received at least one dose of vaccine or alum only (n=71 for phase 1 and n=479 for phase 2; safety population). In the combined safety profile of phase 1 and phase 2, any adverse reactions within 28 days after injection occurred in 56 (26%) of 219 participants in the 1·5 µg group, 63 (29%) of 217 in the 3·0 µg group, and 27 (24%) of 114 in the alum-only group, without significant difference (p=0·55). Most adverse reactions were mild and moderate in severity. Injection site pain was the most frequently reported event (73 [13%] of 550 participants), occurring in 36 (16%) of 219 participants in the 1·5 µg group, 35 (16%) of 217 in the 3·0 µg group, and two (2%) in the alum-only group. As of June 12, 2021, only one serious adverse event of pneumonia has been reported in the alum-only group, which was considered unrelated to vaccination. In phase 1, seroconversion of neutralising antibody after the second dose was observed in 27 of 27 participants (100·0% [95% CI 87·2-100·0]) in the 1·5 µg group and 26 of 26 participants (100·0% [86·8-100·0]) in the 3·0 µg group, with the geometric mean titres of 55·0 (95% CI 38·9-77·9) and 117·4 (87·8-157·0). In phase 2, seroconversion was seen in 180 of 186 participants (96·8% [93·1-98·8]) in the 1·5 µg group and 180 of 180 participants (100·0% [98·0-100·0]) in the 3·0 µg group, with the geometric mean titres of 86·4 (73·9-101·0) and 142·2 (124·7-162·1). There were no detectable antibody responses in the alum-only groups. INTERPRETATION: CoronaVac was well tolerated and safe and induced humoral responses in children and adolescents aged 3-17 years. Neutralising antibody titres induced by the 3·0 µg dose were higher than those of the 1·5 µg dose. The results support the use of 3·0 µg dose with a two-immunisation schedule for further studies in children and adolescents. FUNDING: The Chinese National Key Research and Development Program and the Beijing Science and Technology Program.

8.
Nutr Diabetes ; 11(1): 24, 2021 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193814

RESUMO

BACKGROUND: Patients with both diabetes mellitus (DM) and kidney disease could have diabetic nephropathy (DN) or non-diabetic renal disease (NDRD). IgA nephropathy (IgAN) and membranous nephropathy (MN) are the major types of NDRD. No ideal noninvasive diagnostic model exists for differentiating them. Our study sought to construct diagnostic models for these diseases and to identify noninvasive biomarkers that can reflect the severity and prognosis of DN. METHODS: The diagnostic models were constructed using logistic regression analysis and were validated in an external cohort by receiver operating characteristic curve analysis method. The associations between these microRNAs and disease severity and prognosis were explored using Pearson correlation analysis, Cox regression, Kaplan-Meier survival curves, and log-rank tests. RESULTS: Our diagnostic models showed that miR-95-3p, miR-185-5p, miR-1246, and miR-631 could serve as simple and noninvasive tools to distinguish patients with DM, DN, DM with IgAN, and DM with MN. The areas under the curve of the diagnostic models for the four diseases were 0.995, 0.863, 0.859, and 0.792, respectively. The miR-95-3p level was positively correlated with the estimated glomerular filtration rate (p < 0.001) but was negatively correlated with serum creatinine (p < 0.01), classes of glomerular lesions (p < 0.05), and scores of interstitial and vascular lesions (p < 0.05). However, the miR-631 level was positively correlated with proteinuria (p < 0.001). A low miR-95-3p level and a high miR-631 level increased the risk of progression to end-stage renal disease (p = 0.002, p = 0.011). CONCLUSIONS: These four microRNAs could be noninvasive tools for distinguishing patients with DN and NDRD. The levels of miR-95-3p and miR-631 could reflect the severity and prognosis of DN.

9.
Appl Radiat Isot ; 176: 109846, 2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34214912

RESUMO

In order to improve the detection sensitivity of 85Kr, an anti-cosmic HPGe γ spectrometer was established and a specific Marinelli beaker was designed for 85Kr measurement. Comparing to the non-anticoincidence γ spectrum, the integral background counts rate range from 20 to 2400 keV was reduced by a factor of 5.17 using anticoincidence shielding. The minimum detectable activity of 85Kr was 10.5 Bq within 24 h measurement in standard mode and that of 3.99 Bq in anticoincidence mode. The activity concentration of atmospheric 85Kr was preliminarily measured to be an average of 1.30 Bq/m3 in Beijing and corresponding minimum detectable concentration was 0.2 Bq/m3.

10.
Oncogene ; 2021 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-34274946

RESUMO

Epigenetic alterations have been previously shown to contribute to multiple myeloma (MM) pathogenesis via DNA methylations and histone modifications. RNA methylation, a novel epigenetic modification, is required for cancer cell survival, and targeting this pathway has been proposed as a new therapeutic strategy. The extent to the N6-methyladenosine (m6A)-regulatory pathway functions in MM remains unknown. Here, we show that an imbalance of RNA methylation may underlies the tumorigenesis of MM. Mechanistically, isocitrate dehydrogenase 2 (IDH2) is highly expressed in CD138+ cells from MM and its levels appear a progressive increase in the progression of plasma cell dyscrasias. Downregulation of IDH2 increases global m6A RNA levels and reduces myeloma cell growth in vitro, decreases the burden of disease and prolongs overall survival in vivo. IDH2 regulates RNA methylation by activating the RNA demethylase FTO, which is an α-KG-dependent dioxygenase. Furthermore, IDH2-mediated FTO activation decreases the m6A level on WNT7B transcripts, then increases WNT7B expression and thus activated Wnt signaling pathway. Moreover, survival analysis indicates that the elevated expression of IDH2 predicts a poor prognosis. Higher expression of FTO is related to higher International Staging System (ISS) stage and higher Revised-ISS (R-ISS) stage of MM. Collectively, our studies reveal that IDH2 regulates global m6A RNA modification in MM via targeting RNA demethylases FTO. The imbalance of m6A methylation activates the Wnt signaling pathway by enhancing the WNT7B expression, and thus promoting tumorigenesis and progression of MM. IDH2 might be used as a therapeutic target and a possible prognostic factor for MM.

11.
Environ Sci Technol ; 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34286959

RESUMO

Hydroxyl radicals (•OH) are important reactive species that are photochemically generated through solar irradiation of chromophoric dissolved organic matter (CDOM) in surface waters. However, the spatial distribution within the complex three-dimensional structure of CDOM has not been examined. In this study, we used a series of hydrophobic chlorinated paraffins as chemical probes to elucidate the microheterogeneous distribution of •OH in illuminated CDOM solutions. The steady-state concentration of •OH inside the CDOM microphase is 210 ± 31-fold higher than the concentration in the aqueous phase. Our results suggest that the most photochemically generated •OH are confined into the CDOM microphase. Thus, illuminated CDOM behaves as a natural microreactor for •OH-based oxidations. By including intra-CDOM •OH, the quantum yield of •OH for CDOM solutions was estimated to be 2.2 ± 0.5 × 10-3, which is 2 orders of magnitude greater than previously thought. The elevated concentrations of photogenerated •OH within the CDOM microphase may improve the understanding of hydrophobic pollutant degradation in aqueous environments. Moreover, our results also suggest that •OH oxidation may play more important roles in the phototransformation of CDOM than previously expected.

12.
J Neuroinflammation ; 18(1): 149, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34225746

RESUMO

BACKGROUND: Microglia are key regulators of the inflammatory response in the brain. Adenosine in RNAs can be converted to m6A (N6-methyladenosine), which regulates RNA metabolism and functions as a key epitranscriptomic modification. The m6A modification pattern and m6A-related signatures under pro-inflammatory and anti-inflammatory conditions of microglia remain unclear. METHODS: Primary rat microglia were differentiated into pro-inflammatory M1-like (M1-L), anti-inflammatory M2-like (M2-L), and resting, unstimulated (M0-L) phenotypes. m6A mRNA and lncRNA epitranscriptomic microarray analyses were performed, and pathway analysis was conducted to understand the functional implications of m6A methylation in mRNAs and lncRNAs. The m6A methylation level and gene expression of mRNAs and lncRNAs were subsequently verified by m6A Me-RIP and qRT-PCR. RESULTS: A total of 1588 mRNAs and 340 lncRNAs, 315 mRNAs and 38 lncRNAs, and 521 mRNAs and 244 lncRNAs were differentially m6A methylated between M1-L and M0-L (M1-L/M0-L), M2-L and M0-L (M2-L/M0-L), M2-L and M1-L (M2-L/M1-L), respectively. Furthermore, 4902 mRNAs, 4676 mRNAs, and 5095 mRNAs were identified distinctively expressed in M1-L/M0-L, M2-L/M0-L, and M2-L/M1-L, respectively. Pathway analysis of differentially m6A methylated mRNAs and lncRNAs in M1-L/M0-L identified immune system, signal transduction, and protein degradation processes. In contrast, the distinct m6A methylated mRNAs in M2-L/M0-L were involved in genetic information processing, metabolism, cellular processes, and neurodegenerative disease-related pathways. We validated m6A methylation and the expression levels of five mRNAs and five lncRNAs, which were involved in upregulated pathways in M1-L/M0-L, and five mRNAs involved in upregulated pathways in M2-L/M0-L. CONCLUSIONS: These findings identify a distinct m6A epitranscriptome in microglia, and which may serve as novel and useful regulator during pro-inflammatory and anti-inflammatory response of microglia.

13.
Cell Signal ; 85: 110068, 2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34197957

RESUMO

Deubiquitinating enzyme (DUB) can hydrolyze ubiquitin molecules from the protein bound with ubiquitin, and reversely regulate protein degradation. The ubiquitin-specific proteases (USP) family are cysteine proteases, which owns the largest members and diverse structure among the currently known DUB. The important roles of ubiquitin-specific peptidase39 (USP39) in cancer have been widely investigated. However, little is known about the putative de-ubiquitination function of USP39 in hepatocellular carcinoma (HCC) and the mechanisms of USP39 regulating tumor growth. Here, we used bioinformatics methods to reveal that USP39 expression is significantly upregulated in several cancer database. High expression of USP39 is correlated with poor prognosis of HCC patients. Then, we identify the specificity protein 1 (SP1), as a novel subtract of the USP39. We observe that USP39 stabilizes SP1 protein and prolongs its half-life by promoting its deubiquitylation pathway. In addition, our results show USP39 promotes cell proliferation by SP1-depenet manner in vivo and vitro. Knocking-down of USP39 promotes the cell apoptosis and arrest of the cell cycle, whereas SP1 forcefully reversed these effects. Taken together, our results suggest that USP39 participates the deubiquitylation of SP1 protein, providing new pathway for understand the upstream signaling for oncogene SP1.

14.
Mol Ecol Resour ; 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34214251

RESUMO

Ark shells are commercially important clam species that inhabit in muddy sediments of shallow coasts in East Asia. For a long time, the lack of genome resources has hindered scientific research of ark shells. Here, we report a high-quality chromosome-level genome assembly of Scapharca kagoshimensis, with an aim to unravel the molecular basis of heme biosynthesis, and develop genomic resources for genetic breeding and population genetics in ark shells. Nineteen scaffolds corresponding to 19 chromosomes were constructed from 938 contigs (contig N50 = 2.01 Mb) to produce a final high-quality assembly with a total length of 1.11 Gb and scaffold N50 around 60.64 Mb. The genome assembly represents 93.4% completeness via matching 303 eukaryota core conserved genes. A total of 24,908 protein-coding genes were predicted and 24,551 genes (98.56%) of which were functionally annotated. The enrichment analyses suggested that genes in heme biosynthesis pathways were expanded and positive selection of the haemoglobin genes was also found in the genome of S. kagoshimensis, which gives important insights into the molecular mechanisms and evolution of the heme biosynthesis in mollusca. The valuable genome assembly of S. kagoshimensis would provide a solid foundation for investigating the molecular mechanisms that underlie the diverse biological functions and evolutionary adaptations of S. kagoshimensis.

16.
Int J Mol Sci ; 22(11)2021 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-34204154

RESUMO

Porphyrins are a widespread group of pigments in nature which are believed to contribute to shell colors in mollusks. Previous studies have provided candidate genes for porphyrin shell coloration, however, the linkage analysis between functional genes and porphyrin pigmentation remains unclear in mollusks. RNA interference is a powerful molecular tool for analyzing the loss of functions of genes in vivo and alter gene expression. In this study, we used unicellular alga Platymonas subcordiformis and Nitzschia closterium f. minutissima as vectors to feed oysters with Escherichia coli strain HT115 engineered to express double-stranded RNAs targeting specific genes involved in porphyrin synthesis. A strain of Crassostrea gigas with orange shell was used to target key haem pathway genes expression using the aforementioned approach. We show here that feeding the oysters with E. coli, containing dsRNA targeting pigmentation genes, can cause changes in the color of the newly deposited shell. For example, the RNAi knockdown of CgALAS and CgPBGD resulted in the loss of uroporphyrin pigmentation from the shell due to the accumulation of the pigment in the oyster's mantle. The study probed the crucial role of ALAS and PBGD genes potential functions of uroporphyrin production and shell color pigmentation in C. gigas.


Assuntos
Crassostrea/metabolismo , Ingestão de Alimentos/fisiologia , Pigmentação , Porfirinas/metabolismo , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , Estruturas Animais/metabolismo , Animais , Crassostrea/genética , Regulação da Expressão Gênica , Fenótipo , Plasmídeos/genética , Transcrição Genética
17.
Int J Biol Sci ; 17(9): 2157-2166, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34239346

RESUMO

Adult mammalian hearts show limited capacity to proliferate after injury, while zebrafish are capable to completely regenerate injured hearts through the proliferation of spared cardiomyocytes. BMP and Notch signaling pathways have been implicated in cardiomyocyte proliferation during zebrafish heart regeneration. However, the molecular mechanism underneath this process as well as the interaction between these two pathways remains to be further explored. In this study we showed BMP signaling was activated after ventricle ablation and acted epistatic downstream of Notch signaling. Inhibition of both signaling pathways differentially influenced ventricle regeneration and cardiomyocyte proliferation, as revealed by time-lapse analysis using a cardiomyocyte-specific FUCCI (fluorescent ubiquitylation-based cell cycle indicator) system. Further experiments revealed that inhibition of BMP and Notch signaling led to cell-cycle arrest at different phases. Overall, our results shed light on the interaction between BMP and Notch signaling pathways and their functions in cardiomyocyte proliferation during cardiac regeneration.

18.
PLoS Pathog ; 17(7): e1009745, 2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34252166

RESUMO

Norovirus (NoV) is the major pathogen causing the outbreaks of the viral gastroenteritis across the world. Among the various genotypes of NoV, GII.4 is the most predominant over the past decades. GII.4 NoVs interact with the histo-blood group antigens (HBGAs) to invade the host cell, and it is believed that the receptor HBGAs may play important roles in selecting the predominate variants by the nature during the evolution of GII.4 NoVs. However, the evolution-induced changes in the HBGA-binding affinity for the GII.4 NoV variants and the mechanism behind the evolution of the NoV-HBGA interactions remain elusive. In the present work, the virus-like particles (VLPs) of the representative GII.4 NoV stains epidemic in the past decades were expressed by using the Hansenula polymorpha yeast expression platform constructed by our laboratory, and then the enzyme linked immunosorbent assay (ELISA)-based HBGA-binding assays as well as the molecular dynamics (MD) simulations combined with the molecular mechanics/generalized born surface area (MMGBSA) calculations were performed to investigate the interactions between various GII.4 strains and different types of HBGAs. The HBGA-binding assays show that for all the studied types of HBGAs, the evolution of GII.4 NoVs results in the increased NoV-HBGA binding affinities, where the early epidemic strains have the lower binding activity and the newly epidemic strains exhibit relative stronger binding intensity. Based on the MD simulation and MMGBSA calculation results, a physical mechanism that accounts for the increased HBGA-binding affinity was proposed. The evolution-involved residue mutations cause the conformational rearrangements of loop-2 (residues 390-396), which result in the narrowing of the receptor-binding pocket and thus tighten the binding of the receptor HBGAs. Our experimental and computational studies are helpful for better understanding the mechanism behind the evolution-induced increasing of HBGA-binding affinity, which may provide useful information for the drug and vaccine designs against GII.4 NoVs.

19.
Artigo em Inglês | MEDLINE | ID: mdl-34207332

RESUMO

Cerebrovascular disease (CVD) is the leading cause of death in many countries including China. Early diagnosis and risk assessment represent one of effective approaches to reduce the CVD-related mortality. The purpose of this study was to understand the prevalence and influencing factors of cerebrovascular disease among community residents in Qingyunpu District, Nanchang City, Jiangxi Province, and to construct a model of cerebrovascular disease risk index suitable for local community residents. A stratified cluster sampling method was used to sample 2147 community residents aged 40 and above, and the prevalence of cerebrovascular diseases and possible risk factors were investigated. It was found that the prevalence of cerebrovascular disease among local residents was 4.5%. Poisson regression analysis found that old age, lack of exercise, hypertension, diabetes, smoking, and family history of cerebrovascular disease are the main risk factors for local cerebrovascular disease. The relative risk ORs were 3.284, 2.306, 2.510, 3.194, 1.949, 2.315, respectively. For these six selected risk factors, a cerebrovascular disease risk prediction model was established using the Harvard Cancer Index method. The R value of the risk prediction model was 1.80 (sensitivity 81.8%, specificity 47.0%), which was able to well predict the risk of cerebrovascular disease among local residents. This provides a scientific basis for the further development of local cerebrovascular disease prevention and control work.

20.
Int J Legal Med ; 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34282483

RESUMO

Diatom test is one of the commonly used diagnostic methods for drowning in forensic pathology, which provides supportive evidence for drowning. However, in forensic practice, it is time-consuming and laborious for forensic experts to classify and count diatoms, whereas artificial intelligence (AI) is superior to human experts in processing data and carrying out classification tasks. Some AI techniques have focused on searching diatoms and classifying diatoms. But, they either could not classify diatoms correctly or were time-consuming. Conventional detection deep network has been used to overcome these problems but failed to detect the occluded diatoms and the diatoms similar to the background heavily, which could lead to false positives or false negatives. In order to figure out the problems above, an improved region-based full convolutional network (R-FCN) with online hard example mining and the shape prior of diatoms was proposed. The online hard example mining (OHEM) was coupled with the R-FCN to boost the capacity of detecting the occluded diatoms and the diatoms similar to the background heavily and the priors of the shape of the common diatoms were explored and introduced to the anchor generation strategy of the region proposal network in the R-FCN to locate the diatoms precisely. The results showed that the proposed approach significantly outperforms several state-of-the-art methods and could detect the diatom precisely without missing the occluded diatoms and the diatoms similar to the background heavily. From the study, we could conclude that (1) the proposed model can locate the position and identify the genera of common diatoms more accurately; (2) this method can reduce the false positives or false negatives in forensic practice; and (3) it is a time-saving method and can be introduced.

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