Temporal Transcriptomic Profiling Reveals Dynamic Changes in Gene Expression of Giant Freshwater Prawn upon Acute Saline-Alkaline Stresses.

Bicarbonate and sulfate are among two primary ion constituents of saline-alkaline water, with excessive levels potentially causing metabolic disorders in crustaceans, affecting their molting and interrupting development. As an economically important crustacean species, the molecular adaptive mechanism of giant freshwater prawn Macrobrachium rosenbergii in response to the stress of bicarbonate and sulfate remains unexplored. To investigate the mechanism underlying NaHCO3, Na2SO4, and mixed NaHCO3, Na2SO4 stresses, M. rosenbergii larvae were exposed to the above three stress conditions, followed by total RNA extraction and high-throughput sequencing at eight distinct time points (0, 4, 8, 12, 24, 48, 72, and 96 h). Subsequent analysis revealed 13, 16, and 13 consistently identified differentially expressed genes (DEGs) across eight time points under three stress conditions. These consistently identified DEGs were significantly involved in the Gene Ontology (GO) terms of chitin-based cuticle development, protein-carbohydrate complex, structural constituent of cuticle, carnitine biosynthetic process, extracellular matrix, and polysaccharide catabolic process, indicating that alkaline stresses might potentially impact the energy metabolism, growth, and molting of M. rosenbergii larvae. Particularly, the transcriptome data revealed that DEGs associated with energy metabolism, immunity, and amino acid metabolism were enriched across multiple time points under three stress conditions. These DEGs are linked to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including glycolysis/glucogenesis, amino sugar and nucleotide sugar metabolism, and lysine degradation. Consistent enrichment findings across the three stress conditions support conclusions above. Together, these insights are instrumental in enhancing our understanding of the molecular mechanisms underlying the alkaline response in M. rosenbergii larvae. Additionally, they offer valuable perspectives on the regulatory mechanisms of freshwater crustaceans amid saline-alkaline water development.

The Role of Biogeography in Shaping Intestinal Flora and Influence on Fatty Acid Composition in Red Swamp Crayfish (Procambarus clarkii).

Intestinal microbiota plays an important role in promoting digestion, metabolism, and immunity. Intestinal microbiota and fatty acids are important indicators to evaluate the health and nutritional composition of Procambarus clarkii. They have been shown to be strongly influence by environmental and genetic factors. However, it is not clear whether environmental factors have a greater impact on the intestinal microbiota and fatty acid composition of crayfish. The link between the intestinal microbial communities and fatty acid (FA) compositions of red swamp crayfish from different geographical has not yet been studied. Thus, the current paper focuses on the influence of different environments on the fatty acids in muscles of crayfish and the possible existence between gut microbiota and fatty acids. Therefore, in this study, we compared the fatty acid compositions and intestinal microbiota of five crayfish populations from different geographical locations. The results were further analyzed to determine whether there is a relationship between geographical location, fatty acid compositions and intestinal microbiota. The gut microbial communities of the crayfish populations were characterized using 16S rRNA high-throughput gene sequencing. The results showed that there were significant differences in FA compositions of crayfish populations from different geographical locations. A similar trend was observed in the gut microbiome, which also varied significantly according to geographic location. Interestingly, the analysis revealed that there was a relationship between fatty acid compositions and intestinal microbes, revealed by alpha diversity analysis and cluster analysis. However, further studies of the interactions between the P. clarkii gut microbiota and biochemical composition are needed, which will ultimately reveal the complexity of microbial ecosystems with potential applications in aquaculture and species conservation.

Effect of Dietary Selenium on the Growth and Immune Systems of Fish.

Dietary selenium (Se) is an essential component that supports fish growth and the immune system. This review attempts to provide insight into the biological impacts of dietary Se, including immunological responses, infection defense, and fish species growth, and it also identifies the routes via which it enters the aquatic environment. Dietary Se is important in fish feed due to its additive, antioxidant, and enzyme properties, which aid in various biological processes. However, excessive intake of it may harm aquatic ecosystems and potentially disrupt the food chain. This review explores the diverse natures of dietary Se, their impact on fish species, and the biological methods for eliminating excesses in aquatic environments. Soil has a potential role in the distribution of Se through erosion from agricultural, industrial, and mine sites. The research on dietary Se's effects on fish immune system and growth can provide knowledge regarding fish health, fish farming strategies, and the health of aquatic ecosystems, promoting the feed industry and sustainable aquaculture. This review provides data and references from various research studies on managing Se levels in aquatic ecosystems, promoting fish conservation, and utilizing Se in farmed fish diets.

Transcriptome analysis of the post-larvae of giant freshwater prawn (Macrobrachium rosenbergii) after IAG gene knockdown with microRNA interference.

The insulin-like androgenic gland hormone gene (IAG) of crustaceans plays pivotal roles in the regulation of sex differentiation. MicroRNAs (miRNAs) are a class of short, non-coding RNAs that function as post-transcriptional gene regulators. However, little information about the regulatory relationship between miRNA and Macrobrachium rosenbergii IAG (MrIAG) were exposed. In this study, we used the 3' untranslated region (UTR) of MrIAG to predict potential target sites of miRNAs. The results showed that miR-184 has one target site in the 3'UTR of MrIAG. Dual-luciferase report assay in vitro confirmed that miR-184 can significantly down-regulate MrIAG expression. Besides, we constructed mutant plasmids of 3'UTR of MrIAG. The result displayed that after co-transfection of mutant plasmids and miR-184 agomir, the activity of luciferase was not affected compared to the control. These results indicated that miR-184 could directly regulate MrIAG. In addition, we found that overexpression of miR-184 in M. rosenbergii can lead to significant changes in the transcription level of genes. Compared with control group, we identified 1510 differentially expressed genes (DEGs) in the miR-184 injection group. Some DEGs were involved in sex differentiation, gonad development, growth and molting were found. qRT-PCR verification was performed on eight DEGs randomly, and the results showed that the expression level of sex-, growth-, and metabolism-related genes changed significantly after MrIAG gene knockdown. Collectively, findings from this study suggest that miR-184, by mediating IAG expression, may be involved in many physiological processes in M. rosenbergii. The current study lays a basic understanding for short-term silencing of MrIAG with miR-184, and facilitates miRNA function analysis in M. rosenbergii in future.

Corrigendum: CEO Empowering Leadership and Corporate Entrepreneurship: The Roles of TMT Information Elaboration and Environmental Dynamism.

[This corrects the article DOI: 10.3389/fpsyg.2021.671232.].

Dietary pectin caused great changes in bile acid profiles of Pelteobagrus fulvidraco.

To reveal the impact of dietary fiber (DF) on the bile acid (BA) profiles of fish, yellow catfish (Pelteobagrus fulvidraco) were fed a diet containing 300 g kg-1 dextrin (CON diet, control) or pectin (a type of soluble DF, PEC diet) for 7 days, and then the BA profiles were analyzed by UHPLC-MS/MS. A total of 26 individuals of BAs were detected in the fish body, with 8, 10, 14, and 22 individuals of BAs detected in the liver, serum, bile, and hindgut digesta, respectively. The conjugated BAs (CBAs) of fish were dominated by taurine CBAs (TCBAs). The concentrations of free BAs (FBAs) and the value of FBAs/CBAs in the bile of fish fed the PEC diet were nearly 5 and 7 times higher, respectively than those in fish fed the CON diet. The value of glycine CBAs/TCBAs in the liver, serum and bile of fish fed the PEC diet was significantly lower, and in the hindgut digesta was higher than that of fish fed the CON diet (P < 0.05). These results suggested that dietary pectin greatly changed the BA profiles of Pelteobagrus fulvidraco, attributed to inhibition of reabsorption of BAs. Therefore, attention should be paid to the impact on BA homeostasis when replacing fishmeal with DF-rich plant ingredients in the fish diet.

CEO Empowering Leadership and Corporate Entrepreneurship: The Roles of TMT Information Elaboration and Environmental Dynamism.

In this paper we investigate the relationship between chief executive officer (CEO) empowering leadership and corporate entrepreneurship. In addition, the mediating role of information elaboration in top management teams (TMTs) and the moderating role of environmental dynamism are examined. Drawing on the information exchange/sharing perspective, we hypothesize that CEO empowering leadership has a positive effect on corporate entrepreneurship, and TMT information elaboration mediates the relationship above. Furthermore, we find that environmental dynamism positively moderates the relationship between empowering leadership and information elaboration, and negatively moderates the relationship between information elaboration and corporate entrepreneurship. Data from a sample of Chinese firms provide empirical evidence in support of these hypotheses.

Daily Challenge/Hindrance Demands and Cognitive Wellbeing: A Multilevel Moderated Mediation Model.

Based on the challenge-hindrance stressor model, this study explored the mechanism of how challenge/hindrance demands affect cognitive wellbeing on a daily basis. Specifically, we examined the mediating effect of work-family enrichment on the relationship between challenge/hindrance demands and cognitive wellbeing. In addition, we tested the moderating effect of overqualification on the relationship between challenge/hindrance demands and work-family enrichment on a daily basis. Finally, we examined the moderated mediation effect of perceived overqualification in a multilevel model. To capture changes in work-family enrichment and cognitive wellbeing that individuals perceived daily, the experience sampling method was adopted to test our theoretical models. A total of 99 participants from China were involved in this investigation. The results showed that daily challenge demands had a significant positive effect on daily cognitive wellbeing, and daily hindrance demands had a significant negative effect on wellbeing. In addition, daily work-family enrichment mediated the positive relationship between daily challenge demands and daily cognitive wellbeing. Moreover, perceived overqualification moderated the relationship between daily challenge demands and daily cognitive wellbeing in the multilevel model. Finally, a significant moderated mediating effect of this overqualification on the indirect effect of daily work-family enrichment on the relationship between daily challenge demands and daily cognitive wellbeing was observed.

Synergy of Effectuation and Causation: An Emotional Complexity Perspective.

This study enriches the literature on entrepreneurial decisions by investigating the antecedents of the synergetic use of causal and effectual logic. Based on entrepreneurial metacognition and emotional complexity theories, we argued that the emotional complexity of an entrepreneur, referred to as the granular experience of, or variety in, experienced emotions during the entrepreneurial task, would contribute to the synergetic use of decision logic. With survey data gathered from 218 Chinese entrepreneurs, we found that entrepreneurs with higher emotional complexity are more likely to adopt two types of entrepreneurial logic in tandem, and cognitive flexibility mediates this positive relationship. Thereby, this study helps to unravel some of the complexities behind the choice of decision logic of entrepreneurs.

Insights into the Gut Microbiota of Freshwater Shrimp and Its Associations with the Surrounding Microbiota and Environmental Factors.

The gut microbiota of aquatic animals plays a crucial role in host health through nutrient acquisition and outcompetition of pathogens. In this study, on the basis of the high-throughput sequencing of 16S rRNA gene amplicons, we examined the bacterial communities in the gut of freshwater shrimp (Macrobrachium nipponense) and in their living environments (sediment and pond water) and analyzed the effects of abiotic and biotic factors on the shrimp gut bacterial communities. High bacterial heterogeneity was observed in the freshwater shrimp gut samples, and the result indicated that both the surrounding bacterial community and water quality factors (particularly dissolved oxygen and temperature) could affect the shrimp gut bacterial community. Despite the observed heterogeneity, 57 genera, constituting 38%-99% of the total genera in each of the 40 shrimp gut samples, were identified as the main bacterial population in the gut of M. nipponense. In addition, a high diversity and abundance of lactic acid bacteria (26 genera), which could play significant roles in the digestion process in shrimp, were observed in the shrimp gut samples. Overall, this study provides insights into the gut bacterial communities of freshwater shrimp and basic information for shrimp farming regarding the application of probiotics and disease prevention.

Metagenomic analysis revealed the prevalence of antibiotic resistance genes in the gut and living environment of freshwater shrimp.

Antibiotic resistance disseminating from animals and their environments is a public issue that poses significant threats to human health. In the present study, the diversity and abundance of antibiotic resistance genes (ARGs) in 15 samples from the guts and related aquaculture environments (water and sediment) of shrimp were investigated. In total, 60 ARGs, 102 ARGs and 67 ARGs primarily belonging to 13, 15 and 15 different types were detected in the shrimp gut, pond water and sediment samples, respectively. Efflux pump and target modification were the predominant resistance mechanisms in all samples. It was found that Aeromonas, Yersinia and Clostridium XlVb were significantly correlated with the distribution of the ARGs. Besides, the relative abundance of ARGs was positively correlated with the levels of mobile genetic elements (MGEs). Moreover, variation partitioning analysis showed that MGEs, contributing to 74.46% of the resistome variation, played an important role in the affecting of the antibiotic resistome than the bacterial communities and their joint effects. Collectively, this study provides comprehensive information to better understand the ARG dissemination in aquaculture environments and to improve the ecological management of aquatic ecosystems.