61 research outputs found

    Self-Regulated Learning and Academic Achievement in Blended Learning in China

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    College students who participate in blended learning face a greater challenge because they cannot achieve good academic achievement without self-regulated learning (SRL). The purpose of this study is to examine the SRL level of students, investigate the correlation between SRL and achievement, and determine the predictive power of SRL on achievement. A questionnaire was distributed to 90 students at a university in Shandong, China. The data were analyzed using descriptive analysis, correlation analysis, and regression analysis. As a result of the findings of this study, instructors will gain a better understanding of how to design language curricula that incorporates SRL into blended learning to enhance students’ SRL

    Arabidopsis lox3 lox4 double mutants are male sterile and defective in global proliferative arrest

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    Fertility and flower development are both controlled in part by jasmonates, fatty acid-derived mediators produced via the activity of 13-lipoxygenases (13-LOXs). The Arabidopsis thaliana Columbia-0 reference genome is predicted to encode four of these enzymes and it is already known that one of these, LOX2, is dispensable for fertility. In this study, the roles of the other three 13-LOXs (LOX3, LOX4 and LOX6) were investigated in single and double mutants. Four independent lox3 lox4 double mutants assembled with different mutated lox3 and lox4 alleles had fully penetrant floral phenotypes, displaying abnormal anther maturation and defective dehiscence. The plants were no longer self-fertile and pollen was not viable. Fertility in the double mutant was restored genetically by complementation with either the LOX3 or the LOX4 cDNAs and biochemically with exogenous jasmonic acid. Furthermore, deficiency in LOX3 and LOX4 causes developmental dysfunctions, compared to wild type; lox3 lox4 double mutants are taller and develop more inflorescence shoots and flowers. Further analysis revealed that developmental arrest in the lox3 lox4 inflorescence occurs with the production of an abnormal carpelloid flower. This distinguishes lox3 lox4 mutants from the wild type where developmentally typical flower buds are the terminal inflorescence structures observed in both the laboratory and in nature. Our studies of lox3 lox4 as well as other jasmonic acid biosynthesis and perception mutants show that this plant hormone is not only required for male fertility but also involved in global proliferative arres

    Anti-epiphyte defenses in the red seaweed Gracilaria vermiculophylla : non-native algae are better defended than their native conspecifics

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    Epibiosis in the marine environment is a stressor that may determine invasion success in introduced species. Previous comparisons showed resistance to epibionts can be higher in non-native than in resident seaweed species, but we do not know whether it is an intrinsic trait of the non-natives or it has been acquired during the invasion process. To elucidate this question, a comparison between native and non-native populations of the same species is needed. Resistance against two groups of epiphytes was assessed in living thalli and in artificial substrata coated with surface extracts, both gained from four Asian (native) and four European (non-native) populations of the red alga Gracilaria vermiculophylla. Two diatom species and two filamentous macroalgae were used as micro- and macro-epiphytes, and one of each type was collected in Asia, while the other came from Europe. Laboratory assays were done in both distributional ranges of G. vermiculophylla and in different seasons. We used G. vermiculophylla from four populations in each range and used a fully crossed design with the factors (i) ‘Origin of Gracilaria’, (ii) ‘Origin of epiphytes’, (iii) ‘Season’ and (iv) ‘Solvent used for extraction’. Both groups of epiphytes, regardless of their origin, attached less to living thalli and to surface extracts from non-native G. vermiculophylla. Fewer diatoms attached to hexane-based extracts, while fewer Ceramium filaments settled on extracts gained with dichloromethane. Synthesis. Our results show for the first time that non-native individuals of a marine organism are better defended against epiphytes than native conspecifics. Furthermore, we found evidence that at least a part of the defence is based on extractable secondary metabolites. We discuss several mechanisms that could explain the increased resistance to epiphytes in non-native individuals, including the release from enemies in the non-native range, which could lead to an increase in algal performance during the invasion process. We suggest that an enhanced defence against epiphytes after introduction is one reason for G. vermiculophylla's invasion success. Our observation may also apply to other basibiont–epibiont and host–enemy systems, including plant–plant, plant–animal and animal–animal interactions, in aquatic environments and could be a key feature of bioinvasions

    How do microbiota associated with an invasive seaweed vary across scales?

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    Communities are shaped by scale dependent processes. To study the diversity and variation of microbial communities across scales, the invasive and widespread seaweed Agarophyton vermiculophyllum presents a unique opportunity. We characterized pro‐ and eukaryotic communities associated with this holobiont across its known distribution range, which stretches over the northern hemisphere. Our data reveal that community composition and diversity in the holobiont vary at local but also larger geographic scales. While processes acting at the local scale (i.e., within population) are the main structuring drivers of associated microbial communities, changes in community composition also depend on processes acting at larger geographic scales. Interestingly, the largest analysed scale (i.e., native and non‐native ranges) explained variation in the prevalence of predicted functional groups, which could suggest a functional shift in microbiota occurred over the course of the invasion process. While high variability in microbiota at the local scale supports A. vermiculophyllum to be a generalist host, we also identified a number of core taxa. These geographically independent holobiont members imply that cointroduction of specific microbiota may have additionally promoted the invasion process

    Can targeted defense elicitation improve seaweed aquaculture?

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    Diseases increasingly threaten aquaculture of kelps and other seaweeds. At the same time, protection concepts that are based upon application of biocides are usually not applicable, as such compounds would be rapidly diluted in the sea, causing ecological damage. An alternative concept could be the application of immune stimulants to prevent and control diseases in farmed seaweeds. We here present a pilot study that investigated the effects of oligoalginate elicitation on juvenile and adult sporophytes of Saccharina japonica cultivated in China and on adult sporophytes of Saccharina latissima cultivated in Germany. In two consecutive years, treatment with oligoalginate clearly reduced the detachment of S. japonica juveniles from their substrate curtains during the nursery stage in greenhouse ponds. Oligoalginate elicitation also decreased the density of endobionts and the number of bacterial cells on sporophytes of S. latissima that were cultivated on sea-based rafts. However, the treatment increased the susceptibility of kelp adults to settlement of epibionts (barnacles in Germany and filamentous algal epiphytes in China). In addition, oligoalginate elicitation accelerated the aging of S. japonica adults. Based upon these findings, oligoalginate elicitation could be a feasible way to provide “environmentally friendly” protection of kelp juveniles in nurseries. The same treatment causes not only beneficial, but also unwanted effects in adult kelp sporophytes. Therefore, it is not recommended as a treatment after the juvenile stage is completed. Future tests with other elicitors and other cultivated seaweed species may allow for the development of more feasible applications of targeted defense elicitation in seaweed aquaculture

    Machine learning to construct sphingolipid metabolism genes signature to characterize the immune landscape and prognosis of patients with uveal melanoma

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    BackgroundUveal melanoma (UVM) is the most common primary intraocular malignancy in adults and is highly metastatic, resulting in a poor patient prognosis. Sphingolipid metabolism plays an important role in tumor development, diagnosis, and prognosis. This study aimed to establish a reliable signature based on sphingolipid metabolism genes (SMGs), thus providing a new perspective for assessing immunotherapy response and prognosis in patients with UVM.MethodsIn this study, SMGs were used to classify UVM from the TCGA-UVM and GEO cohorts. Genes significantly associated with prognosis in UVM patients were screened using univariate cox regression analysis. The most significantly characterized genes were obtained by machine learning, and 4-SMGs prognosis signature was constructed by stepwise multifactorial cox. External validation was performed in the GSE84976 cohort. The level of immune infiltration of 4-SMGs in high- and low-risk patients was analyzed by platforms such as CIBERSORT. The prediction of 4-SMGs on immunotherapy and immune checkpoint blockade (ICB) response in UVM patients was assessed by ImmuCellAI and TIP portals.Results4-SMGs were considered to be strongly associated with the prognosis of UVM and were good predictors of UVM prognosis. Multivariate analysis found that the model was an independent predictor of UVM, with patients in the low-risk group having higher overall survival than those in the high-risk group. The nomogram constructed from clinical characteristics and risk scores had good prognostic power. The high-risk group showed better results when receiving immunotherapy.Conclusions4-SMGs signature and nomogram showed excellent predictive performance and provided a new perspective for assessing pre-immune efficacy, which will facilitate future precision immuno-oncology studies

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    Early development of grateloupia turuturu (Halymeniaceae, Rhodophyta)

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    Grateloupia turuturu is a commercial red alga with potential value in nutraceuticals and pharmaceuticals. To supplement information on its life history and verify whether carpospores can be used for seedling culture, early development of G. turuturu was investigated under culture conditions (27°C, 10–13 ÎŒol/(m2·s) in irradiance, photoperiod 10:14 h L:D). Three physiological stages were recognized by continuous microscopic observation: division stage, discoid crust stage, and juvenile seedling stage. At the beginning of the division stage, the carpospores developed germ tubes into which the carpospore protoplasm was evacuated, and then the carpospore protoplasm in the germ tubes began to divide continuously until discoid crusts formed. Finally, upright thalli appeared on the discoid crusts and developed into juvenile seedlings. It took about 60 days for carpospores to develop into juvenile seedlings. The growth parameters, including germination rate for carpospores and discoid crust diameter, were recorded. These results contribute more information on the life cycle, and at the same time are of great significance in the scaling-up of artificial seedling cultures of G. turuturu
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