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To understand the fish diversity in the upper reaches of the Yangtze River in Chongqing, environmental DNA (eDNA) technology was used to analyze the fish diversity during a one-year water body sampling period from April 2021 to January 2022. The results showed that a total of 82 fish species (including Oreochromis, which was not identified to species level). 7 orders and 19 families and 63 genera were detected in the Jiangbei Section of the upper Yangtze River in Chongqing including 5 species of national key protected animals, 8 species of endemic animals in the upper reaches of Yangtze River and 8 exotic species. The number of fish species showed a seasonal trend of autumn > winter > summer > spring, among which Cyprinus carpio, Hypophthalmichthys nobilis, Pelteobagrus fulvidraco, Hemiculter tchangi and Ctenopharyngodon idella were all detected in the four seasons and had high sequence abundance. The Chao1 and ACE indices differed significantly between seasons (P<0.05) and the alpha diversity index in winter was higher than the three other seasons. The PCoA results showed that the heterogeneity between spring and summer samples was low and the species composition was similar, while the fish species composition in autumn and winter were significantly different and the heterogeneity was high. RDA analysis showed that water level, water flow and water temperature were the main factors affecting the seasonal distribution of the fish community. They were negatively correlated with water temperature and water flow, positively correlated with water level in spring and summer, and negatively correlated with water temperature and flow and positively correlated with water level in winter. Spearman's correlation test showed that water temperature was significantly negatively correlated with Shannon diversity, Chao1 index and ACE index (P<0.01); conductivity was negatively correlated with Coverage index (P<0.05), and water temperature, water flow was negatively correlated with Simp- son diversity (P<0.05). Overall, this study shows that eDNA technology can rapidly analyze fish species composition and distribution, and has great potential and importance in the monitoring fish resources in the Yangtze River. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the effects of information technology (IT) capability on firm growth in the context of open technological innovation. The paper utilized a logical deductive approach to develop hypotheses and analytical frameworks, and collected empirical data from 256 Chinese new ventures. Regression analysis and structural equation models were used to test the hypotheses and analyze the data. The results showed that IT capability, including flexibility and integration of information technology, significantly influenced firm growth, and open technological innovation partially mediated the relationship between IT flexibility and firm growth, and significantly mediated the relationship between IT integration and firm growth. The paper's limitations include the cross-sectional design, limited sample size, and potential unobserved variables such as organizational learning that could affect the relationship between IT capability and firm growth. The research is the first to investigate the effects of IT capability on firm growth based on the mediation of open technological innovation in China, contributing to the literature on IT capability and providing insights for managerial practice in the sharing economy era. [ABSTRACT FROM AUTHOR]

Simple Summary: Thyrotropin-releasing hormone (TRH) is an important upstream regulator in the hypothalamus-pituitary-thyroid (HPT) axis in mammals. In this study, we isolated and characterized trh gene from a protogynous hermaphrodite fish rice field eel Monopterus albus. TRH had no significant effect on serum thyroid hormone levels in rice field eel. However, we found that TRH was involved in the regulation gonadal differentiation-related gene expression and serum sex steroid hormone secretion. Our results indicated that TRH may play a novel role in gonadal differentiation in rice field eel. Rice field eel (Monopterus albus), a protogynous hermaphrodite fish, is a good model for the research of sex determination and gonadal differentiation in teleosts. In this study, we cloned the full-length cDNA sequence of trh, which encoded a predicted protein with 270 amino acids. Trh mainly expressed in the brain, followed by the ovary, testis, muscle and pituitary, and had low levels in other peripheral tissues. During natural sex reversal, trh mRNA expression levels exhibited a significant increase at the late intersexual stage in the hypothalamus. In the gonad, trh mRNA expression levels showed a trend of increase followed by decrease, and only increased significantly at the middle intersexual stage. No matter static incubation or intraperitoneal (IP) injection, TRH had no significant effect on trh and thyroid-stimulating hormone βsubunit (tshβ) mRNA expression levels, and serum T3, T4 and TRH release. After static incubation of ovarian fragments by TRH, the expression of gonadal soma derived factor (gsdf) was up-regulated significantly at both the doses of 10 and 100 nM. IP injection of TRH stimulated the expression of gsdf, and inhibited the expression of ovarian aromatase gene (cyp19a1a), accompanied by the increase of serum 11-KT levels. The results indicated that TRH may play a novel role in gonadal differentiation by the regulation of gonadal differentiation-related gene expression and sex steroid hormone secretion in rice field eel. [ABSTRACT FROM AUTHOR]

Nowadays, the cultivation mode of Hyriopsis cumingii urgently needs transformation and upgrading, and realizing sustainable aquaculture lacks the selection of suitable algae and the exploration of culture conditions. This experiment is to evaluate combined effects of ration levels (low ration, medium ration and high ration) and temperature (13.0 ± 0.2°C, 23.0 ± 0.2°C, and 33.0 ± 0.2°C) on immune responses of H. cumingii. Activities of immune enzymes (alkaline phosphatase, superoxide dismutase, catalase and lysozyme) and expression of immune‐related genes (interleukin‐17 and inhibitor of apoptosis protein) in mussels were analysed during 21 days exposure period. Results suggested that the diatom Navicula pelliculosa was suitable algae for H. cumingii, the optimal ration level and temperature of H. cumingii were the medium ration and 23℃. Semi‐starvation, excessive dietary, low‐ or high‐temperature stimulated immune activities, and when beyond the immune regulation range, most immune enzyme activities decreased. Acute stress also stimulated expression of HcIL‐17 and IAP, and long‐term stress of discomfort temperature and ration levels led to immune dysfunction and affected expression of these genes. The study has practical significance in realizing the sustainable aquaculture of H. cumingii and provides a broader perspective regarding the water ecosystem. [ABSTRACT FROM AUTHOR]

Standard single‐exposure of calcein (CAL) was conducted on juvenile silver carp, Hypophthalmichthys molitrix, to examine its effects on antioxidant enzyme levels and lipid peroxidation. Juveniles were exposed to different concentrations of CAL solutions (0, 100, 300, 500 and 700 mg/L) for different immersion periods (12, 24, 48, 72 and 96 hr). Increased glutamate‐oxaloacetate transaminase, glutamate‐pyruvate transaminase and alkaline phosphatases activities were assumed to be due to CAL‐induced hepatic damage, probably because of the high potential of CAL to accumulate in fish hepatopancreas. Higher CAL concentrations (>300 mg/L) and prolonged immersion periods (>48 hr) could lead to greater toxicity in juvenile silver carp and, to a certain degree, damage the gills and hepatopancreas. The antioxidant responses in the gills and hepatopancreas result in successful elimination of the excess CAL‐induced reactive oxygen species for CAL exposure ≤24 hr. Our results confirmed that the toxic effects of CAL on antioxidant enzyme levels and lipid peroxidation in juvenile silver carp depended on both CAL concentrations and duration of exposure. Moreover, concentration of CAL solutions and the immersion period should be, respectively, restricted to ≤300 mg/L and ≤24 hr, when CAL is used for immersion marking juvenile silver carp. [ABSTRACT FROM AUTHOR]

Hyriopsis cumingii plays an important role in aquatic ecosystems and fishery economy due to its potential value for water purification and edibleness. The present study was undertaken to reveal the short- and long-term purifying effects of H. cumingii on pond water. The short-term experiment results showed that total suspended solids, particulate organic carbon, and fatty acid in water were significantly eliminated by H. cumingii, with average percentage of filtering effect respectively reaching 22.19%, 57.48%, and 21.00% in the high-density group. Analogously, H. cumingii could significantly reduce phytoplankton biomass, species number, density, and chlorophyll-a concentration, especially in the control of diatoms, green algae, and cyanobacteria. Besides, electric conductivity also was significantly reduced by H. cumingii and its variation tendency showed a typical density-dependent effect. Similar purification effects were observed in chemical oxygen demand (COD), total nitrogen, and total phosphorus. In the long-term monitoring test, H. cumingii has also shown positive effects on the water transparency and the control to phytoplankton and COD in recirculating aquaculture pond. Overall, H. cumingii showed excellent ecological function, and the mixed breeding density of shellfish in the recirculating aquaculture pond is worth further exploration. [ABSTRACT FROM AUTHOR]

Tropical cyclone (hereafter as TC) is one of the serious environmental disasters. In order to promote theoretical research into prevention and control of TCs, the current developments and trends in research on economic loss assessment of TCs around the world need to be understood. In this paper, bibliometric visualization analysis is used to analyze research progress based on literature collected from the Web of Science Core Collection database. The evolution trend of years and countries, cooperation networks, major scholars, knowledge bases, key topics, hotspots and challenges were presented quantitatively through keyword co-occurrence analysis, burst strength analysis, cluster analysis and keyword strategy matrix. The results indicate that the USA currently has the most influential studies. The top four topics in this research field are the influence of TCs on forest ecosystem, human health, social and economic system, along with the research on the influence of TCs under climate change. In addition, more studies considering the vulnerability, variability and risk assessment of TCs need to be further investigated in the future. Through quantitative literature analysis and review, this paper can help interested scholars develop a deeper understanding of the current situation and future trends in research on economic loss assessment of TCs. [ABSTRACT FROM AUTHOR]

In August 2019, massive mortalities of cultured Hyriopsis cumingii occurred in a local shellfish breeding experimental base in Chongqing, China. In this report, we identified 14 isolates from cultured mussels in mortality events and demonstrated that these strains caused mortality from 9% to 97%. Significant mussel mortality (p <.05) was observed in association with most isolates after bacterial challenge; however, considerable variation in the virulence of different isolates was noted, with survival ranging from 3% to 88% after 7 days. The most virulent strains (HOP3 and GL1) in haemolymph and tissues were identified as Stenotrophomonas maltophilia and Aeromonas veronii based on biochemical and 16S rDNA sequence analysis. The LD50 values of HOP3 and GL1 were found to be 2.45 × 106 CFU/g (body weight) and 2.24 × 105 CFU/g (body weight) respectively. Histopathology of H. cumingii infected with S. maltophilia and A. veronii displayed degeneration of muscle fibres and gill necrosis. We tested the antibiotic susceptibility of the two isolates and found that HOP3 was multidrug‐resistant. Growth optimization study revealed that both isolates remained surviving across wide environmental ranges. Our data lay the foundation for the pathogenic mechanism of mussel bacterial diseases, and they also suggest that effective control measures are worth further investigation. [ABSTRACT FROM AUTHOR]

Marking fish with fluorochrome dyes has the potential to produce detectable marks in otoliths, scales, fin rays, fin spines, and other bony structures based on differential staining of chemical dyes, and it is a widely used technique for mass-marking fish that included both teleosts and elasmobranchs. This technique, which has relatively economic advantages and simple marking process, can be applied to fish of all ages, and these fluorescent marks can be retained for several months and even years. Up to now, >200 fish species have been successfully marked by this marking technique. Fluorescent labeling is a practical and available marking technique for large-scale marking hatchery-reared fish. The methodology of fluorescent labeling is reviewed, including fluorochrome labeling dyes, application method, detection, and evaluation strategies. Aspects of practical applications, limitations, and supervision of fluorescent labeling are also discussed. [ABSTRACT FROM AUTHOR]

Microbes, as an important part of aquaculture ponds, can improve the recirculation of nutrients. This nearly 1-year-long study aimed to understand the factors and mechanisms that cause temporal changes in the concentration of microbiological indicators and nutrient concentration in the grass carp pond water of Chongqing Jiguan Aquaculture Limited. The study was comprised of five sampling campaigns, with samples spaced 2 months apart. Water temperature, dissolved oxygen and pH were measured in the field during sampling, and the concentration of nitrates, nitrites and phosphates were determined afterward in the laboratory. Subsequent analysis of 16s genome sequencing classified microorganisms into 32 phyla and 481 genera and revealed the core composition of the bacterial community for each season. Principal component analysis revealed that pathogens (Pseudomonas and Flavobacterium) are a significant negative correlation with water temperature and a positive correlation with ammonium concentration and dissolved oxygen. Bacillus and Streptomyces population size was negatively correlated with total phosphorus, while Lactobacillus and Bacteroides populations were positively correlated with water temperature and negatively correlated with ammonium salt. These findings reveal a significant relationship between microbial communities and the physicochemical parameters in aquaculture environments, providing a basis for further improving the aquaculture environment. [ABSTRACT FROM AUTHOR]

How does one connect two of the most important rivers in the world? In the East, China's longest river, the Yangtze, stretches 6300km from the Tibetan Plateau to the port of Shanghai. In the West, the longest river in the United States, the Mississippi, runs 5970 km from northern Minnesota down to the Gulf of Mexico. Both rivers play vital roles in the cultures and economies of their respective countries. Each river system gives life to a wealth of biodiversity while providing millions of people with drinking water, hydroelectric power, and a number of other services. The vitality of the Yangtze and Mississippi faces challenges, however, and the fisheries resources of these two great rivers face specific and common threats. That is why The Nature Conservancy and the Yangtze River Basin Fisheries Resources Management Commission (YFC) came together to form an EcoPartnership to help preserve the natural fisheries of these two great rivers. (Note: YFC recently became the Yangtze Fisheries Bureau, with fisheries responsibilities for all rivers in China from the Yangtze on south and greater administrative authority. The great rivers partnership logo uses the rubric of the Changjiang Fisheries Agency, retaining the Chinese pinyin for the name of the river. [ABSTRACT FROM AUTHOR]

Eutrophication in freshwater has become increasingly severe around the world, resulting in phytoplankton overgrowth and benthic algae reduction. Bivalves can change the density, dominant species and community structure of phytoplankton, increase available light levels, and provide physical habitats and growth conditions for benthic algae. The nutritional composition, density, community structure, and toxin of algae affect the growth, feeding, digestion, metabolism, immunity of bivalves in return. Interactions of bivalves and algae and effects of environmental factors on these interactions need a synthesis of studies, when using bivalves as a biomanipulation tool to control eutrophication. Whether bivalves can effectively suppress phytoplankton and promote benthic algae is related to the collective filtration and excretion capacity determined by size, species, population densities of bivalves, the quantity and quality of algae, and environmental factors such as temperature, dissolved oxygen, pH, and hydrodynamic. Small scale bivalve biomanipulation experiments are mostly conducted in lakes, urban ponds, and reservoirs with some success, applying in the whole ecosystem should consider more questions such as natural conditions, selection and death or reproduction of bivalves, and ecological disturbances. This review provides new considerations for technical issues such as the sustainable cultivation of bivalves and the implementation of biomanipulation in eutrophic waters. • Bivalves suppress phytoplankton and promote benthic algae based on ecological functions. • This function is related to collective filtration capacities, particles, environmental factors. • We analyzed the feasibility and limitation of using bivalves for biomanipulation. • The nutritional composition, community structure and toxin of algae affect bivalves' physiology. • Environmental factors influence interactions of bivalves and pelagic-benthic algae. [ABSTRACT FROM AUTHOR]

Ammonia is one of the major pollutants in the aquatic ecosystem. Hyriopsis cumingii has great potential for the restoration of eutrophic water. However, there is no study investigating the effect of ammonia exposure in H. cumingii. The median lethal concentration (96 h LC50) of unionized ammonium was 12.86 mg/L in H. cumingii. In the study, H. cumingii were exposed to 6.43 mg L−1 unionized ammonium (1/2 96 h LC50) for 0, 6, 12, 24, 48, 72, and 96 h. High environment ammonia induced antioxidant response to protect the body from oxidative damage. After exposure to ammonia, there was a same trend of induction followed by inhibition of the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-S-transferases (GST) in the hepatopancreas and gills of H. cumingii. However, the antioxidant response could not completely counteract the oxidation effect during the exposure period, resulting in lipid peroxidation (LPO) and tissue injury in the hepatopancreas and gills of H. cumingii eventually. Moreover, this study indicated that glutamine synthetase (GS), glutamate dehydrogenase (GDH), alanine aminotransaminase (ALT), and aspartate aminotransaminase (AST) in the hepatopancreas and gills may play an important role in ammonia detoxification of H. cumingii. Our results will be helpful to understand the mechanism of aquatic toxicology induced by ammonia in shellfish. [ABSTRACT FROM AUTHOR]

The characteristics of strengthening nanoparticles have a major influence on the mechanical property and irradiation resistance of oxide dispersion strengthened (ODS) steels. In situ small angle neutron scattering (SANS) experiments were performed to determine the evolution of nanoparticles in 9Cr ODS steel powders varied with temperature. Initial-added Y 2 O 3 was completely dissolved into the steel matrix after mechanical alloying. Nanoparticles emerge after annealing at 600 °C for 10 min and coarsen slightly after 12 h. The radius of nanoparticles increases from 0.73 nm at 600 °C to 1.63 nm at 1000 °C, while the volume fraction decreases with increasing annealing temperature. [ABSTRACT FROM AUTHOR]

Abstract: High ammonia (i.e. the total of NH3 and ) concentration or nitrogen deficiency in water can exert stress on growth and health of many aquatic plants. To investigate the physiological impacts of high ammonia-N (NH4Cl) concentration and nitrogen deficiency on plant physiology, apical shoots of submerged macrophyte Egeria densa were first treated with five levels of nitrogen: 0, 1, 10, 30, 60mgL−1 ammonia-N (NH4Cl) for 5d. After having explored the stress range of ammonia-N, its effect on E. densa was further examined at three levels of ammonium (0, 1, 30mgL−1 ammonia-N) and at six exposure times (0, 1, 2, 3, 5 and 7d). In testing the concentration-dependent stress, the increase of ammonia-N reduced the amounts of total chlorophyll (chl a and b), soluble proteins and soluble carbohydrates, but increased the activity levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase and peroxidase in E. densa. In the N-free medium, total chlorophyll, soluble proteins, soluble carbohydrates and the activities of SOD and peroxidase in E. densa decreased significantly compared with the control (1mgL−1 ammonia-N). When comparing the ammonia-N impacts over time, the plants showed a declining trend in total chlorophyll, soluble proteins and soluble carbohydrates, but an rising trend in MDA, SOD, peroxidase and catalase in 30mgL−1 ammonia-N over 7d. Compared with the control, the N-free medium significantly decreased the amounts of total chlorophyll, soluble proteins, soluble carbohydrates, SOD and peroxidase in E. densa over time. Our study indicates that high ammonium (ammonia-N⩾10mgL−1) affects the growth of E. densa through inducing oxidative stress and inhibiting photosynthesis, and nitrogen deficiency can also induce an abiotic stress condition for the E. densa growth by reducing photosynthetic pigments, soluble proteins, soluble carbohydrates, and the activity of antioxidant enzymes. [Copyright &y& Elsevier]

Thyroid-stimulating hormone (TSH) is an important glycoprotein in hypothalamic-pituitary-thyroid axis, which plays a crucial role in the synthesis and release of thyroid hormones in vertebrates. Rice field eel, Monopterus albus , a protogynous hermaphroditic fish, which undergoes sex reversal from a functional female to a male, is an ideal model to investigate the regulation of sex differentiation. In this study, we obtained the cDNA sequence of thyroid-stimulating hormone β subunit (tshβ) from rice field eel, which contained a complete open reading frame and encoded a putative protein of 151 amino acids. Multiple alignment of protein sequences showed that tshβ was highly conserved in teleost. The tissue distribution indicated that tshβ showed high expression in the pituitary, moderate expression in the brain region, gonad, intestine and liver, and low expression in other peripheral tissues. During natural sex reversal, the expression of tshβ had no significant difference in the pituitary. Compared to that in the ovary, the expression of tshβ increased significantly in the gonad at late intersexual and male stages. After treatment by different doses of triiodothyronine (T3) (1 μg/g, 10 μg/g and 100 μg/g body weight), serum T3 and free triiodothyronine (FT3) increased sharply, while the expression of tshβ were inhibited significantly in the pituitary. Although T3 had no significant effect on the levels of serum E2, it stimulated the release of serum 11-KT at high-dose group. We also detected the effects of T3 on the expression of gonadal differentiation-related genes in rice field eel. T3 treatment inhibited the expression of foxl2 , cyp19a1a and dax1 , while stimulated the expression of sox9a1. These results indicate that TSH may be involved in sex differentiation, and THs may play roles in the regulation of male development and sex reversal in rice field eel. [Display omitted] • Rice field eel tsh β was cloned and characterized, which was highly conserved in teleost. • T sh β showed high expression in the pituitary, moderate expression in the brain region and gonad. • The expression of tsh β increased at late intersexual and male stages in the gonad. • T3 stimulated the release of serum 11-KT at high-dose group. • T3 treatment inhibited the expression of foxl2 , cyp19a1a and dax1 , while stimulated the expression of sox9a. [ABSTRACT FROM AUTHOR]

The ecologically and economically important bivalve species Hyriopsis cumingii is affected by numerous bacterial diseases, but the effects of these harmful bacteria on the antioxidant responses and histological alterations of H. cumingii are unclear. This study evaluated the effects of common pathogenic infections on immune function in H. cumingii. A series of antioxidant enzyme activities, total haemocyte counts, and histopathological changes were measured at 24, 48, and 96 h post infection (hpi) with three pathogens (Aeromonas hydrophila , Streptococcus agalactiae , and Pseudomonas fluorescens). All enzyme activities sharply decreased or remained constant at 24 hpi, except for acid phosphatase and alkaline phosphatase activities in the P. fluorescens -infected group. However, peroxidase activity significantly increased at 24 and 48 hpi in all treatments (p < 0.05), followed by a time-dependent decrease. The lysozyme, superoxide dismutase, and glutathione peroxidase activities decreased first and then gradually approached the control levels at 96 hpi. In our observations, there were five major types of haemocytes in H. cumingii , including mainly granulocytes and hyalinocytes. Bacterial infection increased total haemocyte counts and especially the proportion of granulocytes. Moreover, infection resulted in tissue oedema, columnar cell disarrangement, and epidermal detachment. Overall, our data provide a new perspective on the initiation of innate immunity after bacterial challenge in H. cumingii. • The effects of environmental pathogens on Hyriopsis cumingii were determined. • Pathological changes of the foot tissues in the pathogens-infected mussels were observed. • Pseudomonas fluorescens caused more severe effects on H. cumingii than Aeromonas hydrophila and Streptococcus agalactiae. [ABSTRACT FROM AUTHOR]