Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 128
Filtrar
1.
Food Res Int ; 140: 109850, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33648168

RESUMO

Mongolian cheese is non-fermented cheese, which easily deteriorates during storage because of hydrolysis. The freezing points of sucrose and sucrose-free cheese were measured -5.16 °C and -4.29 °C, respectively. Ice-storage temperatures of -2 °C and -4 °C were used and 0 °C was used as reference temperature. In this study, the changes of proteolytic indexes (PI) and total viable counts (TVC) of cheese at different ice-temperatures during storage were studied. The PIs of all treatments increased over storage time, which conformed to the Arrhenius first-order kinetic model. The shelf lives of sucrose and sucrose-free cheese were predicted. In addition, -4 °C effectively suppressed the increases in TVC and PIs. The split-split-plot design was applied in comparing the effects of cheese type, the storage time and storage temperature on PI. Storage time was the most important factor followed by cheese type and storage temperature.

2.
Parasit Vectors ; 14(1): 129, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33648570

RESUMO

BACKGROUND: The departure of the mature larvae of the horse stomach bot fly from the host indicates the beginning of a new infection period. Gasterophilus pecorum is the dominant bot fly species in the desert steppe of the Kalamaili Nature Reserve (KNR) of northwest China as a result of its particular biological characteristics. The population dynamics of G. pecorum were studied to elucidate the population development of this species in the arid desert steppe. METHODS: Larvae in the freshly excreted feces of tracked Przewalski's horses (Equus przewalskii) were collected and recorded. The larval pupation experiments were carried out under natural conditions. RESULTS: There was a positive correlation between the survival rate and the number of larvae expelled (r = 0.630, p < 0.01); the correlation indicated that the species had characteristic peaks of occurrence. The main periods during which mature larvae were expelled in the feces were from early April to early May (peak I) and from mid-August to early September (peak II); the larval population curve showed a sudden increase and gradual decrease at both peaks. Under the higher temperatures of peak II, the adults developing from the larvae had a higher survival rate, higher pupation rate, higher emergence rate and shorter eclosion period than those developing from peak I larvae. Although G. pecorum has only one generation per year, its occurrence peaked twice annually, i.e. the studied population has a bimodal distribution, which doubles parasitic pressure on the local host. This phenomenon is very rarely recorded in studies on insect life history, and especially in those on parasite epidemiology. CONCLUSION: The period during which G. pecorum larvae are naturally expelled from the host exceeds 7 months in KNR, which indicates that there is potentially a long period during which hosts can become infected with this parasite. The phenomenon of two annual peaks of larvae expelled in feces is important as it provides one explanation for the high rate of equine myiasis in KNR.

3.
Cell Host Microbe ; 29(3): 489-502.e8, 2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33548198

RESUMO

The SARS-CoV-2 virus, the causative agent of COVID-19, is undergoing constant mutation. Here, we utilized an integrative approach combining epidemiology, virus genome sequencing, clinical phenotyping, and experimental validation to locate mutations of clinical importance. We identified 35 recurrent variants, some of which are associated with clinical phenotypes related to severity. One variant, containing a deletion in the Nsp1-coding region (Δ500-532), was found in more than 20% of our sequenced samples and associates with higher RT-PCR cycle thresholds and lower serum IFN-ß levels of infected patients. Deletion variants in this locus were found in 37 countries worldwide, and viruses isolated from clinical samples or engineered by reverse genetics with related deletions in Nsp1 also induce lower IFN-ß responses in infected Calu-3 cells. Taken together, our virologic surveillance characterizes recurrent genetic diversity and identified mutations in Nsp1 of biological and clinical importance, which collectively may aid molecular diagnostics and drug design.


Assuntos
/imunologia , Interferon Tipo I/imunologia , /imunologia , Proteínas não Estruturais Virais/genética , Células A549 , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Sequência de Bases , Linhagem Celular , Criança , Pré-Escolar , Chlorocebus aethiops , Feminino , Deleção de Genes , Genômica , Células HEK293 , Humanos , Lactente , Interferon Tipo I/sangue , Interferon beta/sangue , Interferon beta/metabolismo , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Genética Reversa , Células Vero , Proteínas não Estruturais Virais/imunologia , Adulto Jovem
4.
Andrologia ; 53(3): e13980, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33528066

RESUMO

Transducin (ß)-like 1 X-linked receptor 1 (TBL1XR1) is an evolutionarily conserved protein related to spermatozoa. To clarify its role and mechanism of action in spermatozoa, qRT-PCR was used to analyse the expression of TBL1XR1 in human spermatozoa and mouse testes. The mice were established as an animal model by injecting the mice testes with small interfering RNA against TBL1XR1 or control siRNA. Our results indicated that deficiency of TBL1XR1 in mice reduced the motility of spermatozoa and disrupted the histone-to-protamine transition. We also found the decreased expression of TBL1XR1 in the spermatozoa of human patients with asthenozoospermia (AZ) compared with that in the spermatozoa of healthy males. Moreover, we carried out chromatin immunoprecipitation analyses and found that genes downstream of TBL1XR1 were related to sperm motility. Thus, TBL1XR1 might be related to sperm motility and might function through its downstream genes. Our data highlight the role of TBL1XR1 involved in spermatozoa and provide new molecular insights into the intricate systems required for male fertility.

5.
Artigo em Inglês | MEDLINE | ID: mdl-33600328

RESUMO

Measurement of total-plaque-area (TPA) is important for determining long term risk for stroke and monitoring carotid plaque progression. Since delineation of carotid plaques is required, a deep learning method can provide automatic plaque segmentations and TPA measurements; however, it requires large datasets and manual annotations for training with unknown performance on new datasets. A UNet++ ensemble algorithm was proposed to segment plaques from 2D carotid ultrasound images, trained on three small datasets (n=33, 33, 34 subjects) and tested on 44 subjects from the SPARC dataset (n=144, London, Canada). The ensemble was also trained on the entire SPARC dataset and tested with a different dataset (n=497, Zhongnan Hospital, China). Algorithm and manual segmentations were compared using Dice-similarity-coefficient (DSC) and TPAs were compared using the difference (TPA), Pearson correlation coefficient (r), and Bland-Altman analyses. Segmentation variability was determined using the intra-class correlation coefficient (ICC) and coefficient-of-variation (CoV). For the 44 SPARC subjects, algorithm DSC was 83.3-85.7%, and algorithm TPAs were strongly correlated (r=0.985-0.988; p<0.001) with manual results with marginal biases (0.73-6.75) mm2 using the three training datasets. Algorithm ICC for TPAs (ICC=0.996) was similar to intra- and inter-observer manual results (ICC=0.977, 0.995). Algorithm CoV=6.98% for plaque areas was smaller than the inter-observer manual CoV (7.54%). For the Zhongnan dataset, DSC was 88.6%; algorithm and manual TPAs were strongly correlated (r=0.972, p<0.001) with TPA=-0.444.05 mm2 and ICC=0.985. The proposed algorithm trained on small datasets and segmented a different dataset without retraining with accuracy and precision that may be useful clinically and for research.

6.
Cell Res ; 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33390587

RESUMO

Glioblastoma (GBM) is an incurable and highly heterogeneous brain tumor, originating from human neural stem/progenitor cells (hNSCs/hNPCs) years ahead of diagnosis. Despite extensive efforts to characterize hNSCs and end-stage GBM at bulk and single-cell levels, the de novo gliomagenic path from hNSCs is largely unknown due to technical difficulties in early-stage sampling and preclinical modeling. Here, we established two highly penetrant hNSC-derived malignant glioma models, which resemble the histopathology and transcriptional heterogeneity of human GBM. Integrating time-series analyses of whole-exome sequencing, bulk and single-cell RNA-seq, we reconstructed gliomagenic trajectories, and identified a persistent NSC-like population at all stages of tumorigenesis. Through trajectory analyses and lineage tracing, we showed that tumor progression is primarily driven by multi-step transcriptional reprogramming and fate-switches in the NSC-like cells, which sequentially generate malignant heterogeneity and induce tumor phenotype transitions. We further uncovered stage-specific oncogenic cascades, and among the candidate genes we functionally validated C1QL1 as a new glioma-promoting factor. Importantly, the neurogenic-to-gliogenic switch in NSC-like cells marks an early stage characterized by a burst of oncogenic alterations, during which transient AP-1 inhibition is sufficient to inhibit gliomagenesis. Together, our results reveal previously undercharacterized molecular dynamics and fate choices driving de novo gliomagenesis from hNSCs, and provide a blueprint for potential early-stage treatment/diagnosis for GBM.

7.
J Assist Reprod Genet ; 38(3): 697-707, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33409754

RESUMO

PURPOSE: A growing number of Chinese individuals of reproductive age will face the choice of accepting or refusing expanded carrier screening (ECS). This study aimed to explore the awareness, wishes, and possible misconceptions of ECS among this population, as well as factors affecting their decision-making. METHODS: Chinese reproductive-aged individuals in Eastern China who sought cell-free fetal DNA screening and peripheral blood karyotype were invited to complete a 31-item ECS survey by scanning a specific quick response code. We evaluated the relationship between awareness, attitudes, and intentions to participate in ECS, along with possible misconceptions. RESULTS: Overall, 93.1% of participants intended to undergo ECS at their expenses, and 53.6% indicated they would pay less than 1000 CNY (approximately 145 USD) for the test. Around 96.5% of participants had misconceptions about ECS and genetic diseases. Participants whose first reaction was interest, who had prior awareness of the test, or who perceived benefits were more likely to intend to use ECS (p < 0.001). Participants with a bachelor's degree or above or with a household income over 150,000 CNY (approximately 21,700 USD) would be more likely to pay ≥ 1000 CNY (p < 0.05). CONCLUSIONS: Our study indicates that overall, the Eastern Chinese reproductive-aged population has positive attitudes towards ECS, although there are some misconceptions about ECS and genetic disorders. Population-based ECS appears to be desired by the reproductive-aged people in Eastern China. Steps should be taken to offer ECS along with pre- and post-test education and genetic counseling to raise awareness and to reduce misconceptions.

8.
Talanta ; 224: 121784, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33379013

RESUMO

Fluorine and chlorine are key elements to affecting water quality, but they are hard to be determined by conventional laser-induced breakdown spectroscopy (LIBS). To achieve high sensitivity detection of them, the CaF and CaCl molecules were synthesized by combining calcium in calcite and F and Cl in sample. The temporal characteristics of CaF and CaCl molecular emissions were investigated. It shows that molecular emission of CaF and CaCl has a longer lifetime and high spectral intensity than that of their atomic emissions. Such unique feature of molecular emission inspired us to use it for high sensitivity analysis of Cl and F elements in water. The results show that these two elements can be sensitively and accurately detected using LIBS assisted with molecular emission. The limits of detections (LoDs) were 0.38 mg/L and 1.03 mg/L for F and Cl elements, respectively, and the limit of quantitation (LoQ) was 3.404 mg/L to 20.569 mg/L for fluorine elements and 9.986 mg/L to 39.757 mg/L for fluorine. These detection limits can meet the World Health Organization's detection requirements for F and Cl elements in water. The results show that LIBS assisted with molecular synthesis has a huge potential in water quality monitoring.

9.
Water Sci Technol ; 82(11): 2296-2303, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33339785

RESUMO

In this study, the removal effect of free and immobilized bacteria on crude oil was determined. Sodium alginate and polyvinyl alcohol were used as embedding agent, and ramie was modified as an adsorbent to immobilize free bacteria. The conditions for preparing immobilized pellets were optimized using the response surface method, and the best combination was simulated and obtained by Design-Expert 8.0. The best degradation rate of immobilized bacteria was 75.52%. The degradation by free bacteria and immobilized bacteria showed that the selected microorganisms had a good degradation effect on petroleum hydrocarbons.


Assuntos
Poluição por Petróleo , Petróleo , Bactérias , Biodegradação Ambiental , Hidrocarbonetos
10.
J Mol Diagn ; 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33069876

RESUMO

Embryonic chromosomal abnormalities are the major cause of miscarriage. An accurate, rapid, and cheap method of chromosome analysis in miscarriage is warranted in clinical practice. Thus, a high-throughput ligation-dependent probe amplification (HLPA)-based method of detecting aneuploidies and copy number variations in miscarriage was developed. A total of 1060 cases of miscarriage were assessed. Each specimen was subjected to quantitative fluorescence (QF)-PCR/HLPA and chromosomal microarray analysis (CMA) in parallel. All 1060 samples were successfully analyzed using both methods; of these samples, 1.7% (18/1060) were identified as having significant maternal cell contamination. Among the remaining 1042 cases without significant maternal cell contamination, QF-PCR/HLPA reached a diagnostic yield of 59.6% (621/1042), which is comparable to the yield of 60.3% (628/1042) with CMA. Compared with CMA results, the sensitivity and specificity of QF-PCR/HLPA in the identification of total pathogenic chromosomal abnormalities were 98.9% and 100%, respectively. Furthermore, the overall prevalence of chromosomal abnormalities in cases of spontaneous abortion was not significantly different from that in cases of recurrent miscarriage (61.3% versus 58.5%). In summary, QF-PCR/HLPA rapidly and accurately identified chromosomal abnormalities at a comparable performance and lower cost as compared with CMA. Combining simplicity and accuracy with cost-effectiveness, QF-PCR/HLPA may serve as a promising approach to routine genetic testing in miscarriage in clinical practice.

11.
Mol Biol Evol ; 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33027519

RESUMO

Dioecy, the presence of separate sexes on distinct individuals, has evolved repeatedly in multiple plant lineages. However, the specific mechanisms by which sex systems evolve and their commonalities among plant species remain poorly understood. With both XY and ZW sex systems, the family Salicaceae provides a system to uncover the evolutionary forces driving sex chromosome turnovers. In this study, we performed a genome-wide association study to characterize sex determination in two Populus species, P. euphratica and P. alba. Our results reveal an XY system of sex determination on chromosome 14 of P. euphratica, and a ZW system on chromosome 19 of P. alba. We further assembled the corresponding sex determination regions, and found that their sex chromosome turnovers may be driven by the repeated translocations of a Helitron-like transposon. During the translocation, this factor may have captured partial or intact sequences that are orthologous to a type-A cytokinin response regulator gene. Based on results from this and other recently published studies, we hypothesize that this gene may act as a master regulator of sex determination for the entire family. We propose a general model to explain how the XY and ZW sex systems in this family can be determined by the same RR gene. Our study provides new insights into the diversification of incipient sex chromosomes in flowering plants by showing how transposition and rearrangement of a single gene can control sex in both XY and ZW systems.

12.
Sensors (Basel) ; 20(21)2020 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-33113788

RESUMO

New ongoing rural construction has resulted in an extensive mixture of new settlements with old ones in the rural areas of China. Understanding the spatial characteristic of these rural settlements is of crucial importance as it provides essential information for land management and decision-making. Despite a great advance in High Spatial Resolution (HSR) satellite images and deep learning techniques, it remains a challenging task for mapping rural settlements accurately because of their irregular morphology and distribution pattern. In this study, we proposed a novel framework to map rural settlements by leveraging the merits of Gaofen-2 HSR images and representation learning of deep learning. We combined a dilated residual convolutional network (Dilated-ResNet) and a multi-scale context subnetwork into an end-to-end architecture in order to learn high resolution feature representations from HSR images and to aggregate and refine the multi-scale features extracted by the aforementioned network. Our experiment in Tongxiang city showed that the proposed framework effectively mapped and discriminated rural settlements with an overall accuracy of 98% and Kappa coefficient of 85%, achieving comparable and improved performance compared to other existing methods. Our results bring tangible benefits to support other convolutional neural network (CNN)-based methods in accurate and timely rural settlement mapping, particularly when up-to-date ground truth is absent. The proposed method does not only offer an effective way to extract rural settlement from HSR images but open a new opportunity to obtain spatial-explicit understanding of rural settlements.

13.
Biomed Res Int ; 2020: 5175393, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33015171

RESUMO

Background: Shock is one of the causes of mortality in the intensive care unit (ICU). Traditionally, hemodynamics related to shock have been monitored by broad-spectrum devices with treatment guided by many inaccurate variables to describe the pathophysiological changes. Critical care ultrasound (CCUS) has been widely advocated as a preferred tool to monitor shock patients. The purpose of this study was to analyze and broaden current knowledge of the characteristics of ultrasonic hemodynamic pattern and investigate their relationship to outcome. Methods: This prospective study of shock patients in CCUS was conducted in 181 adult patients between April 2016 and June 2017 in the Department of Intensive Care Unit of West China Hospital. CCUS was performed within the initial 6 hours after shock patients were enrolled. The demographic and clinical characteristics, ultrasonic pattern of hemodynamics, and outcome were recorded. A stepwise bivariate logistic regression model was established to identify the correlation between ultrasonic variables and the 28-day mortality. Results: A total of 181 patients with shock were included in our study (male/female: 113/68). The mean age was 58.2 ± 18.0 years; the mean Acute Physiology and Chronic Health Evaluation II (APACHE II score) was 23.7 ± 8.7, and the 28-day mortality was 44.8% (81/181). The details of ultrasonic pattern were well represented, and the multivariate analysis revealed that mitral annular plane systolic excursion (MAPSE), mitral annular peak systolic velocity (S'-MV), tricuspid annular plane systolic excursion (TAPSE), and lung ultrasound score (LUSS) were the independent risk factors for 28-day mortality in our study, as well as APACHE II score, PaO2/FiO2, and lactate (p = 0.047, 0.041, 0.022, 0.002, 0.027, 0.028, and 0.01, respectively). Conclusions: CCUS exam on admission provided valuable information to describe the pathophysiological changes of shock patients and the mechanism of shock. Several critical variables obtained by CCUS were related to outcome, hence deserving more attention in clinical decision-making. Trial Registration. The study was approved by the Ethics Committee of West China Hospital Review Board for human research with the following reference number 201736 and was registered on ClinicalTrials. This trial is registered with NCT03082326 on 3 March 2017 (retrospectively registered).

14.
Sci Rep ; 10(1): 15731, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978441

RESUMO

Oviposition by Gasterophilus pecorum on shoot tips of Stipa caucasica is a key determinant of its severe infection of the reintroduced Przewalski's horse (Equus przewalskii). Volatiles in shoots of grasses on which Przewalski's horse feeds, including S. caucasica at preoviposition, oviposition, and postoviposition stages of G. pecorum, S. caucasica, Stipa orientalis, and Ceratoides latens at the oviposition stage, and S. caucasica in various growth periods, were collected by dynamic headspace adsorption and analyzed by automatic thermal desorption gas chromatography-mass spectrometry. Among five volatiles with highest relative contents under three sets of conditions, caprolactam and 3-hexen-1-ol,(Z)- were common to all samples. Caprolactam was highest in C. latens at oviposition stage of G. pecorum and lowest in S. caucasica at postoviposition stage, and that of 3-hexen-1-ol,(Z)- was lowest in C. latens and highest in S. caucasica at its oviposition stage. Particularly, in S. caucasica during the three oviposition phenological stages of G. pecorum, 3-hexen-1-ol,acetate,(Z)-, 2(5H)-furanone,5-ethyl-, and 3-hexen-1-ol,acetate,(E)- were unique, respectively, to the preoviposition, oviposition, and postoviposition stages; in three plant species during the oviposition stage of G. pecorum, 3-hexen-1-ol,acetate,(Z)-, 3-hexenal, and 1-hexanol were unique to S. orientalis, acetic acid, hexanal, and 2(5H)-furanone,5-ethyl- to S. caucasica, and 1,3,6-octatriene,3,7-dimethyl-, cis-3-hexenyl isovalerate, and acetic acid hexyl ester to C. latens; in S. caucasica, 2-undecanone,6,10-dimethyl- was unique to the early growth period, acetic acid and 2(5H)-furanone,5-ethyl- to the flourishing growth period, and 3-hexen-1-ol,acetate,(Z)- and 1,3,6-octatriene,3,7-dimethyl- to the late growth period. Furthermore, substances specific to S. orientalis and C. latens were also present in S. caucasica, except at oviposition stage. Our findings will facilitate studies on G. pecorum's adaptation to the arid desert steppe and its future control.

15.
Eur J Med Res ; 25(1): 43, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32943114

RESUMO

BACKGROUND: Hepatic fibrosis (HF), which is characterized by the excessive accumulation of extracellular matrix (ECM) in the liver, usually progresses to liver cirrhosis and then death. To screen differentially expressed (DE) long non-coding RNAs (lncRNAs) and mRNAs, explore their potential functions to elucidate the underlying mechanisms of HF. METHODS: The microarray of GSE80601 was downloaded from the Gene Expression Omnibus database, which is based on the GPL1355 platform. Screening for the differentially expressed LncRNAs and mRNAs was conducted between the control and model groups. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to analyze the biological functions and pathways of the DE mRNAs. Additionally, the protein-protein interaction (PPI) network was delineated. In addition, utilizing the Weighted Gene Co-expression Network Analysis (WGCNA) package and Cytoscape software, we constructed lncRNA-mRNA weighted co-expression networks. RESULTS: A total of 254 significantly differentially expressed lncRNAs and 472 mRNAs were identified. GO and KEGG analyses revealed that DE mRNAs regulated HF by participating in the GO terms of metabolic process, inflammatory response, response to wounding and oxidation-reduction. DE mRNAs were also significantly enriched in the pathways of ECM-receptor interaction, PI3K-Akt signaling pathway, focal adhesion (FA), retinol metabolism and metabolic pathways. Moreover, 24 lncRNAs associated with 40 differentially expressed genes were observed in the modules of lncRNA-mRNA weighted co-expression network. CONCLUSIONS: This study revealed crucial information on the molecular mechanisms of HF and laid a foundation for subsequent genes validation and functional studies, which could contribute to the development of novel diagnostic markers and provide new therapeutic targets for the clinical treatment of HF.

16.
Addict Behav ; 111: 106569, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32739589

RESUMO

Although Social Network Site (SNS) usage has been shown to be related to online compulsive buying among women, little is known about the mediating mechanisms underlying this association. Based on the Interaction of Person-Affect-Cognition-Execution model (I-PACE) for addictive behaviors and social comparison theory, the present study examined the mediating roles of upward social comparison and state anxiety in the link between passive SNS usage and online compulsive buying among female undergraduate students. A sample of 799 Chinese female undergraduate students (mean age = 19.86 years, SD = 1.63) were recruited to complete questionnaires measuring passive SNS usage, upward social comparison on SNS, state anxiety, and online compulsive buying. After controlling for online shopping experience, the results showed that passive SNS usage was positively associated with online compulsive buying; upward social comparison and state anxiety partially mediated this link, which contained three mediating pathways - the separate mediating effect of upward social comparison and state anxiety, and the sequential mediating effect of upward social comparison and state anxiety. These findings can advance our understanding of how passive SNS usage is related to online compulsive buying among female undergraduate students. Limitations and implications of this study are discussed.

17.
Genes (Basel) ; 11(8)2020 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-32722098

RESUMO

The ages and sizes of a sex-determination region (SDR) are difficult to determine in non-model species. Due to the lack of recombination and enrichment of repetitive elements in SDRs, the quality of assembly with short sequencing reads is universally low. Unique features present in the SDRs help provide clues about how SDRs are established and how they evolve in the absence of recombination. Several Populus species have been reported with a male heterogametic configuration of sex (XX/XY system) mapped on chromosome 19, but the exact location of the SDR has been inconsistent among species, and thus far, none of these SDRs has been fully assembled in a genomic context. Here we identify the Y-SDR from a Y-linked contig directly from a long-read PacBio assembly of a Populus trichocarpa male individual. We also identified homologous gene sequences in the SDR of P. trichocarpa and the SDR of the W chromosome in Salix purpurea. We show that inverted repeats (IRs) found in the Y-SDR and the W-SDR are lineage-specific. We hypothesize that, although the two IRs are derived from the same orthologous gene within each species, they likely have independent evolutionary histories. Furthermore, the truncated inverted repeats in P. trichocarpa may code for small RNAs that target the homologous gene for RNA-directed DNA methylation. These findings support the hypothesis that diverse sex-determining systems may be achieved through similar evolutionary pathways, thereby providing a possible mechanism to explain the lability of sex-determination systems in plants in general.

18.
Anal Methods ; 12(27): 3530-3536, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32672299

RESUMO

Rapid and accurate measurement of coal quality has great significance for efficient use of coal at thermal power plants. Laser-induced breakdown spectroscopy (LIBS) combined with chemometric methods has many unique advantages in coal analysis. In this study, four calibration models, based on partial least squares regression (PLSR), support vector regression (SVR), artificial neural network (ANN), and principal component regression (PCR), were applied assisted by the LIBS technique for the quantitative analysis of coal quality. In order to find the optimal calibration method with LIBS for coal analysis, the spectral data of 40 standard coal samples with pressed-pellet pretreatment were acquired through a LIBS experimental setup, and the modeling efficiency and prediction accuracy of the four chemometric methods were compared based on these spectral data. As a result, the modeling efficiency of PLSR was found to be the highest, that of SVR was the lowest, and that of ANN ranked third. In terms of prediction performance, ANN was found to work better than the other three chemometric methods, and the average absolute error (AAE) of prediction of ash content, volatile matter content and calorific value were 0.69%, 0.87%, and 0.56 MJ kg-1, respectively. ANN can seek the best compromise of modeling efficiency and prediction accuracy and is demonstrated to be an optimal multivariate calibration method with LIBS for online measurement of coal quality at thermal power plants.

19.
Ann Transl Med ; 8(9): 577, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32566604

RESUMO

Background: We investigated the correlation between glucose metabolism patterns of different immune cells and the metabolic regulatory signaling pathways in myasthenia gravis (MG) and aimed to identify therapeutic targets for MG. Methods: We isolated peripheral blood mononuclear cells (PBMCs) and sorted CD19+B cells, dendritic cells (DCs), CD4+ T cells, CD8+ T cells, CD4+CD25+ regulatory T cells (Tregs), CD4+CD25-T cells, and T helper (Th) cells such as Th1, Th2, and Th17 cells. Then, we detected the expression levels of PI3K/AKT/mTOR-HIF-1α, GLUT1, hexokinase (HK), phosphofructokinase (PFK), and pyruvate kinase (PK) by RT-PCR, measured the oxygen consumption rate and extracellular acidification rate of ex vivo freshly sorted cells using the Seahorse XFe96 Analyzer. In addition, we compared the glycolysis levels using these cells from the same MG patients. By performing in vitro experiments, we measured, the mRNA expression levels of mTOR, HIF-1α, B cell activating factor receptor (BAFF-R), GLUT1, HK, PFK, and PK, in addition to ECAR profiles, frequency of CD80 and CD86, and IgG levels from the culture supernatant of B cells (isolated from MG patients) treated with rapamycin and PX-478 (selective mTOR and HIF-1α inhibitor, respectively) from. Results: Except PBMCs, Th2 and CD8+ T cells, the expression levels of the key enzymes involved in glycolysis and HIF-1α were significantly higher in B cells, DCs, Tregs, CD4+CD25-T cells, and Th1 and Th17 cells in MG patients, and the measurement of ECAR and OCR confirmed the metabolic status. In MG patients, B cells and DCs showed significantly higher levels of glycolysis and glycolytic capacity than CD8+ T cells, CD4+ T cells and its subsets. In vitro, except IgG levels, the increased glycolysis levels, expression of key glycolytic enzymes, BAFF-R and frequency of CD80 and CD86 of B cells, could be inhibited by rapamycin and PX-478. Conclusions: Different subtypes of immune cells in MG exhibit different glucose metabolism patterns. The mTOR-HIF-1α signaling pathway might be the immunometabolism reprogramming checkpoint of glycolysis-dependent activated B cells in MG.

20.
J Food Biochem ; 44(8): e13328, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32578894

RESUMO

Hami melon (Cucumis melo var. saccharinus) is famous in China because of its delicious taste. The fast post-harvest metabolism of Hami melon, which is harvested in summer, creates challenges for preservation during storage. In this study, the ripening-related changes in Hami melon were monitored throughout postharvest storage, including transport. The effects of hot water (HW) treatment and HW treatment in combination with O-carboxymethyl chitosan (CMC) coating on ripening were evaluated based on the changes in membrane leakage; respiration rates; malondialdehyde (MDA) content; superoxide dismutase, catalase, and peroxidase activities; total antioxidant capacity (TAC); and total phenolic content during storage. Transmission electron microscopy and magnetic resonance imaging were also used to monitor changes in the quality of Hami melons during storage. The results indicate that transport vibration can accelerate ripening-related changes in Hami melon. Transport vibration increased membrane leakage and microstructural changes in the melon tissue; enhanced the respiration rate and MDA content; suppressed the activities of antioxidant enzymes; and decreased the TAC and total phenolic contents. Compared to HW treatment alone, HW treatment combined with the coating with 1% (w/v) CMC more effectively delayed the ripening-related changes in Hami melons under transport vibration. PRACTICAL APPLICATIONS: The results of this study show that transport vibration can accelerate ripening in Hami melons. Both hot water (HW) treatment and a combination of HW treatment and O-carboxymethyl chitosan (CMC) coating were effective in delaying ripening in Hami melons under simulated long-term transport vibration. Compared with HW treatment alone, HW treatment combined with CMC coating was more effective in preserving Hami melons, as indicated by lower respiration rates; better integrity of the plasma membrane and cell wall in the parenchyma tissue; lower membrane leakage and malondialdehyde content; greater antioxidant enzyme activities, total antioxidant capacity, and total phenolic content; and improved magnetic resonance imaging T2 relaxation values. Thus, HW treatment combined with CMC coating provides a useful way for the Hami melon industry to maintain postharvest quality, extend the shelf life, and improve the marketing of Hami melon.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...