Institute of Hydrobiology, Chinese Academy Of Sciences
Not a member yet
20118 research outputs found
Sort by
Occurrence and characteristics of microplastics in the Haihe River: An investigation of a seagoing river flowing through a megacity in northern China
No full textFreshwater systems serve as important sources and transportation routes for marine microplastic pollution, and inadequate attention has been paid to this situation. Data on microplastic pollution of typical seagoing rivers in northern China are lacking. In the current study, we investigated the distribution and characteristics of microplastics in the main stream of the Haihe River, which flows through a metropolis with a high population density and level of industrialization and then flows into the Bohai Sea. The microplastic samples were collected by manta trawls with pore sizes of 333 mm, and the microplastic concentrations ranged from 0.69 to 74.95 items/m(3). Fibers dominated in the surface water of the Haihe River; their shapes that were categorized as fibers, film, foam, fragments, and spheres, and contributed 17.4-86.7% of the total microplastics studied. The size distribution of the microplastics was concentrated in a range of 100-1000 mu m, with 54.7% of the total sizes corresponding to the 333-mu m trawl. Micro-Fourier transform infrared (mu-FT-IR) spectra showed that the main components were polyethylene, poly(ethylene-propylene) copolymer, and polypropylene. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) measurements revealed scratches, micropores, and cracks on the surfaces of the microplastics due to mechanical friction, chemical oxidation and degradation processes. The results of this study confirmed the high abundance and high diversity of microplastics in an urban river and indicated appreciable impacts from point-source inputs on the microplastic pollution, such as effluents from wastewater treatment plants (WWTPs). (C) 2020 Elsevier Ltd. All rights reserved
Grazing rates of freshwater copepod Thermocyclops decipiens (Kiefer, 1929) on Chlorella vulgaris under different light intensities
No full textLight is one of the most important structuring factors for life in aquactic biology. For zooplankton grazers, including copepods, light offers a behavioral dilemma that is potentially present at both small and large scales. We investigated the grazing rate, clearance rate, fecal pellet production rate, egg production rate, percertage of egg hatching and survival percentage of the freshwater copepod Thermocyclops deceipiens under different light intensities (0 lx, 500 lx, 1500 lx) over periods of 15 days. For the grazing experiment the fresh water microalgae Chlorella vulgaris was used at concentrations 2-6 x 10(6) cells/mL(-1). The grazing rates of the copepod decreased at higher light intensities when compared to other treatments. Maximum grazing rate and the clearance rate occurred in the treatment with 500 lx (70,490 cells copepod(-1) h(-1), 0.23 mL copepod(-1) h(-1)). Egg production rate and hatching rate percentage (17.4 eggs female(-1) day(-1), 99 +/- 0.98%) were also higher at the algae fed with 500 lx light intensity. Copepods survived well and continuously produced fecal pellets on a 500 lx light intensity diet of Chlorella vulgaris. The results suggest that low light intensity influenced the grazing rate, fecundity and survival of copepod T.decipiens
Zebrafish NF-kappa B/p65 Is Required for Antiviral Responses
No full textTranscriptional programs regulated by the NF-kappa B family are essential for the inflammatory response as well as for innate and adaptive immunity. NF-kappa B activation occurs via two major signaling pathways: the canonical and the noncanonical. The canonical NF-kappa B pathway responds to diverse immune stimulations and leads to rapid but transient activation. As a member of the canonical NF-kappa B family, p65 is thought to be a key regulator of viral infection. Because of the embryonic lethality of p65-null mice, the physiological role of p65 in the antiviral immune response is still unclear. In this study, we generated p65-null zebrafish, which were viable and indistinguishable from their wildtype (WT) siblings under normal conditions. However, p65-null zebrafish were more sensitive to spring viremia of carp virus infection than their WT siblings. Further assays indicated that proinflammatory and antiviral genes, including IFN, were downregulated in p65-null zebrafish after spring viremia of carp virus infection compared with their WT siblings. Our results thus suggested that p65 is required for the antiviral response, activating not only proinflammatory genes but also antiviral genes (including IFN)
Global patterns and determinants of lake macrophyte taxonomic, functional and phylogenetic beta diversity
No full textDocumenting the patterns of biological diversity on Earth has always been a central challenge in macroecology and biogeography. However, for the diverse group of freshwater plants, such research program is still in its infancy. Here, we examined global variation in taxonomic, functional and phylogenetic beta diversity patterns of lake macrophytes using regional data from six continents. A data set of ca. 480 lake macrophyte community observations, together with climatic, geographical and environmental variables, was compiled across 16 regions worldwide. We (a) built the very first phylogeny comprising most freshwater plant lineages; (b) exploited a wide array of functional traits that are important to macrophyte autoecology or that relate to lake ecosystem functioning; (c) assessed if different large-scale beta diversity patterns show a clear latitudinal gradient from the equator to the poles using nullmodels; and (d) employed evolutionary and regression models to first identify the degree to which the studied functional traits show a phylogenetic signal, and then to estimate community environment relationships at multiple spatial scales. Our results supported the notion that ecological niches evolved independently of phylogeny in macrophyte lineages worldwide. We also showed that taxonomic and phylogenetic beta diversity followed the typical global trend with higher diversity in the tropics. In addition, we were able to confirm that species, multi-trait and lineage compositions were first and foremost structured by climatic conditions at relatively broad spatial scales. Perhaps more importantly, we showed that large-scale processes along latitudinal and elevational gradients have left a strong footprint in the current diversity patterns and community-environment relationships in lake macrophytes. Overall, our results stress the need for an integrative approach to macroecology, biogeography and conservation biology, combining multiple diversity facets at different spatial scales. (C) 2020 Elsevier B.V. All rights reserved.
Cryptic species inside the genus Hariotina (Scenedesmaceae, Sphaeropleales), with descriptions of four new species in this genus
No full textThe genus Hariotina was established in 1889 based on the type species Hariotina reticulata. This species was then transferred to Coelastrum by Senn (1899). The genus Hariotina was eventually restored by Hegewald et al. (2002) based on morphological characteristics. Species of Hariotina are ubiquitous in fresh water, especially in some tropical and subtropical areas. The taxonomic position of the genus is now considered to be within the family Scenedesmaceae. However, until now, there was an insufficient understanding of the molecular diversity within this genus, and the related reference sequences in the database were inadequate to resolve the species taxonomy. In this study, 20 strains of Hariotina were identified and successfully cultured in the laboratory. We used a combined approach, joining molecular and morphological analyses, to determine their taxonomic relationships and phylogenetic positions. The molecular analyses based on 18S rDNA+ITS sequences and the tufA gene resolved the analysed strains into at least six species, including the known species H. reticulata and H. polychorda and four new species herein described, i.e. H. hainanensis sp. nov., H. compacta sp. nov., H. guilinensis sp. nov. and H. laxa sp. nov. The genus Hariotina was confirmed in the Scenedesmaceae as a monophyletic clade that was closely related to the genus Coelastrum in tufA gene phylogeny. Strains with H. reticulata morphotype were found to be located on two different branches, and formed sister relationships with the other two morphologically distinct species. In addition, the topology was supported by all three DNA markers. The congruence between the phylogeny and the classical taxonomic system based on morphological criteria for this taxon is discussed
Cryptic species inside the genus Hariotina (Scenedesmaceae, Sphaeropleales), with descriptions of four new species in this genus
No full textThe genus Hariotina was established in 1889 based on the type species Hariotina reticulata. This species was then transferred to Coelastrum by Senn (1899). The genus Hariotina was eventually restored by Hegewald et al. (2002) based on morphological characteristics. Species of Hariotina are ubiquitous in fresh water, especially in some tropical and subtropical areas. The taxonomic position of the genus is now considered to be within the family Scenedesmaceae. However, until now, there was an insufficient understanding of the molecular diversity within this genus, and the related reference sequences in the database were inadequate to resolve the species taxonomy. In this study, 20 strains of Hariotina were identified and successfully cultured in the laboratory. We used a combined approach, joining molecular and morphological analyses, to determine their taxonomic relationships and phylogenetic positions. The molecular analyses based on 18S rDNA+ITS sequences and the tufA gene resolved the analysed strains into at least six species, including the known species H. reticulata and H. polychorda and four new species herein described, i.e. H. hainanensis sp. nov., H. compacta sp. nov., H. guilinensis sp. nov. and H. laxa sp. nov. The genus Hariotina was confirmed in the Scenedesmaceae as a monophyletic clade that was closely related to the genus Coelastrum in tufA gene phylogeny. Strains with H. reticulata morphotype were found to be located on two different branches, and formed sister relationships with the other two morphologically distinct species. In addition, the topology was supported by all three DNA markers. The congruence between the phylogeny and the classical taxonomic system based on morphological criteria for this taxon is discussed
Taxonomic scheme of the order Chaetophorales (Chlorophyceae, Chlorophyta) based on chloroplast genomes
No full textAbstractBackgroundOrder Chaetophorales currently includes six families, namely Schizomeridaceae, Aphanochaetaceae, Barrancaceae, Uronemataceae, Fritschiellaceae, and Chaetophoraceae. The phylogenetic relationships of Chaetophorales have been inferred primarily based on short and less informative rDNA sequences. This study aimed to phylogenetically reconstruct order Chaetophorales and determine the taxonomic scheme, and to further understand the evolution of order Chaetophorales.ResultsIn the present study, seven complete and five fragmentary chloroplast genomes were harvested. Phylogenomic and comparative genomic analysis were performed to determine the taxonomic scheme within Chaetophorales. Consequently, Oedogoniales was found to be a sister to a clade linking Chaetophorales and Chaetopeltidales. Schizomeriaceae, and Aphanochaetaceae clustered into a well-resolved basal clade in Chaetophorales, inconsistent with the results of phylogenetic analysis based on rDNA sequences. Comparative genomic analyses revealed that the chloroplast genomes of Schizomeriaceae and Aphanochaetaceae were highly conserved and homologous, highlighting the closest relationship in this order. Germination types of zoospores precisely correlated with the phylogenetic relationships.Conclusionschloroplast genome structure analyses, synteny analyses, and zoospore germination analyses were concurrent with phylogenetic analyses based on the chloroplast genome, and all of them robustly determined the unique taxonomic scheme of Chaetophorales and the relationships of Oedogoniales, Chaetophorales, and Chaetopeltidales.</p
Improvement of nutritional quality of live feed for aquaculture: An overview
No full textIn hatcheries, the adequate supply of live feed has a vital role in feeding fish larvae, fry and fingerlings. Furthermore, the enhancement of the nutritional quality of live feeds is well-developed techniques in aquaculture. Essential fatty acids (EFA) such as docosahexaenoic acid (DHA; C22:6 n-3), eicosapentaenoic acid (EPA; 20:5(n-3) and arachidonic acid (ARA; 20:4(n-6) and amino acids are an essential source of proteins for larval rearing of fish. However, the common practised live feeds used for the primary feeding such as rotifers and Artemia are naturally deficient in essential nutrient components. Hence, the improvement of the nutritional quality of live feeds with different oil emulsions and commercial diets, and manipulation of the feed are necessary for fish production. The production protocols of copepods, Moina and fairy shrimps as live feed are still underdeveloped in hatcheries. The different lipid sources using for the enrichment of Artemia and rotifers are not effective on other live feeds, especially copepods and cladocerans (Moina, Daphnia) and fairy shrimps. This review focuses on the importance of live feeds by the techniques of feed enhancement or enrichment of zooplankton by direct incorporation of nutrients for feeding of early stages of fish
From asymmetrical to balanced genomic diversification during rediploidization: Subgenomic evolution in allotetraploid fish
No full textA persistent enigma is the rarity of polyploidy in animals, compared to its prevalence in plants. Although animal polyploids are thought to experience deleterious genomic chaos during initial polyploidization and subsequent rediploidization processes, this hypothesis has not been tested. We provide an improved reference-quality de novo genome for allotetraploid goldfish whose origin dates to similar to 15 million years ago. Comprehensive analyses identify changes in subgenomic evolution from asymmetrical oscillation in goldfish and common carp to diverse stabilization and balanced gene expression during continuous rediploidization. The homoeologs are coexpressed in most pathways, and their expression dominance shifts temporally during embryogenesis. Homoeolog expression correlates negatively with alternation of DNA methylation. The results show that allotetraploid cyprinids have a unique strategy for balancing subgenomic stabilization and diversification. Rediploidization process in these fishes provides intriguing insights into genome evolution and function in allopolyploid vertebrates
Morphological and molecular characterization of a new freshwater microsporidium, Jirovecia sinensis sp. n. (Microsporidia) infecting the coelomocytes of Branchiura sowerbyi (Oligochaeta: Naididae) in China
No full textWe report a new microsporidium Jirovecia sinensis sp. n. from a freshwater oligochaete, Branchiura sowerbyi collected in Hongze city, Jiangsu province, East China. Numerous whitish hypertrophied coelomocytes of 0.33-0.59 mm in diameter indicated infection. Transmission electron microscopy observations revealed that all developmental stages were diplokaryotic. The earliest life stages observed were meronts that were in direct contact with host cytoplasm, accumulated peripherally in the hypertrophied coelomocytes and connected with host cytoplasm through many pinocytotic canals. Mature spores are rod-shaped with a blunt end, measuring 17.0 +/- 0.1 (14.9-18.5) mu m long and 2.0 +/- 0.2 (1.7-2.2) mu m wide. The most conspicuous character of the novel microsporidian parasite is the tail-like posterior prolongations, with a length of 29.6-40.8 mu m. Mature spores have a manubrium with a diameter of 447-485 nm which consist of six density-discontinuous concentric circles. Spores possess a collar-shaped anchoring disk and a bipartite polarplast with an anterior lamellar region and a posterior tubular section. SSU rDNA-based phylogenetic analysis indicated with high support values that the new species clustered with two Bacillidium species (B. vesiculoformis and Bacillidium sp.) infecting the freshwater oligochaetes and Janacekia debaisieuxi infecting the insect Simulium maculatum. Based on the ultrastructural features and molecular characteristics, a new species in the genus Jirovecia, Jirovecia sinensis sp. n., is designated