Institute of Hydrobiology, Chinese Academy Of Sciences
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Static magnetic field enhanced methane production via stimulating the growth and composition of microbial community
No full textCorn stover has a potentially valuable use as a substrate for biogas production by anaerobic fermentation. Preprocessing of corn stover, such as alkali pretreatment, is usually needed to increase substrate availability. In this study, an experimental biogas production system using a flat circular permanent magnet with a central hole to provide a static magnetic field (SMF) was devised to increase biogas production from corn stover substrate, without pretreatment, by anaerobic fermentation. The effects of varying SMF intensity on the growth of microbe populations in the activated sludge were not linear. Optimal SMF intensity was found to be 11.4 mT (+/- 2%). At this level, the number of microbe populations increased by 85.5% compared to the control. Total gas production and CH4 content of SMF were 19.5% and 20.0% higher than those from the control NMF (no magnetic field). SMF influenced the composition of the bacterial population and significantly increased the percentage of methanogenic archaea in the overall microbe population compared to NMF. Archaea of the order methanocellales were the principal methanogenic archaea found in the decay stage. Our results indicate that SMF can potentially increase biogas production by converting agricultural waste into energy. Life cycle analysis showed that the conversion rate of chemical energy in corn stalks to CH4 was 15.2%. (C) 2020 Elsevier Ltd. All rights reserved
Optimal dietary protein concentrations for largemouth bass (Micropterus salmoides) of different sizes (10-500 g)
No full textThree feeding trials were conducted to determine the optimal dietary protein levels for largemouth bass (Micropterus salmoides) of different sizes. Six isolipidic (12%) diets with different protein levels (46%, 48%, 50%, 52%, 54% and 56%) were tested to feed three size groups of fish for 56 days (Trial 1 and Trial 2) or 84 days (Trial 3). The initial body weights were approximately 10 g in Trial 1, 100 g in Trial 2, and 200 g in Trial 3, respectively. The fish in each size class were randomly distributed into 18 cages (1 m x 1 m x 1 m) in six groups (three replicates) and fed by hand to apparent satiation two times per day. At the end of the feeding trials, the fish grew to an average size of 26-36 g, 276-320 g, and 434-526 g, respectively. The weight gain (WG) showed an increasing trend with increasing dietary protein level up to 52%, 50%, and 48%, respectively, and then plateaued in all the three trials, which indicated that the minimum dietary protein requirements for largemouth bass decrease with increasing fish size. The feed efficiency (FE) in the three trials showed a similar trend to growth performance. Protein efficiency ratio (PER) tended to decline when dietary protein levels exceeded 48%, 50%, and 48% in the three trails, respectively. Broken-line regression analysis showed that the optimal dietary protein levels based on SGR for largemouth bass of different sizes (initial size 10, 100, and 200 g) were 51.6%, 50.5%, and 47.8%, respectively
Molecular cloning, functional characterization and expression analysis of P65 subunit in response to GCRV infection in rare minnow (Gobiocypris rarus)
No full textP65, the all-important subunit of the transcription factor NF-kappa B, plays an important role in the regulation of immune response. In this study, the cDNA of P65 subunit of rare minnow Gobiocypris rarus (GrP65) was cloned, and its expression patterns and functional role in rare minnow were investigated. The GrP65cDNA encodes a polypeptide of 573 amino acids, containing a well-conserved Rel-homology domain (RHD). The amino acid sequence analysis showed that GrP65 shared 81% and 69% identity to the grass carp (Ctenopharyngodon idella) and human (Homo sapiens) orthologous, respectively. Phylogenetic analysis revealed that GrP65 clustered with homologues from other teleosts. Cellular distribution anallysis demonstrated that GrP65 was located in the cytoplasm and nucleus. Quantitative real-time PCR analysis showed that GrP65 was ubiquitously expressed in all examined tissues, but especially highly in liver. Temporal expression analysis in vivo showed that the expression levels of GrP65 were significantly up-regulated in liver in response to GCRV infection, which suggested that GrP65 might play a crucial role in recognition and responses to GCRV infection in fish. In addition, GrP65 activated several interferon (IFN) promoters and induced the expression of downstream IFN-stimulated genes (ISGs). Furthermore, overexpression of P65 remarkably decreased the GCRV proliferation, while knockdown of P65 obtained opposite effects. In summary, we systematically characterized GrP65 and demonstrated its role in the innate immune response to GCRV infections
Reticulocystis yunnanensegen. et sp. nov., a new member of freshwater Oocystaceae algae (Trebouxiophyceae, Chlorophyta)
No full textOocystis -like algae are diverse and found throughout the world. In this study, two new strains of algae with colonies resemblingOocystiswere identified and successfully cultured in the laboratory. A polyphasic approach, including light microscopy, transmission electron microscopy and phylogenetic analyses of 18S rDNA andrbcL cpDNA, was used to characterize the strains. Observation of the two strains showed a regular colonial morphology (cells/daughter colony are parallel to each other and positioned near the edge of the mother cell wall) and a characteristic fibrillar network structure on the mother cell wall is obvious in light microscopy, which distinguished them from otherOocystis-like members described previously. Molecular analyses revealed that the two strains form an independent lineage within the subfamily Makinoelloideae (Oocystaceae, Trebouxiophyceae), separated from other genera. Therefore, we described this alga asReticulocystis yunnanensegen. et sp. nov. The genera of Makinoelloideae with similar colonial morphotypes were revealed as not monophyletic and the relationships between them remained undetermined. Additional taxon sampling and data from additional multiple genes are necessary to assess the taxonomy of the Makinoelloideae
Degraded functional structure of macroinvertebrates caused by commercial sand dredging practices in a flood plain lake
No full textIn parts of developing countries, the over-exploitation of sands from inland waters has led to serious environmental concerns. However, understanding of the impacts of commercial sand dredging on inland water ecosystem functions remains limited. Herein, we assess the effects of this activity on the functional structure of the macroinvertebrate community and its recovery processes based on a 4-year survey, in the South Dongting Lake in China. Our result showed a simplified macroinvertebrate functional structures within the dredged area, as evidenced by a loss of certain trait categories (e.g., oval and conical body form) and a significant reduction in trait values due to the direct removal of macroinvertebrates and indirect alternations to physical environmental conditions (e.g., water depth and %Medium sand). Moreover, clear increases were observed in certain trait categories (e.g., small body size and swimmer) resulting from the dredging-related disturbance (e.g., increased turbidity) within the adjacent area. Furthermore, one year after the cessation of dredging, a marked recovery in the taxonomic and functional structure of macroinvertebrate assemblages was observed with most lost trait categories returning and an increase in the trait values of eight categories (e.g., body size 1.00-3.00 cm and oval body form) within the dredged and adjacent area. In addition, dispersal processes and sediment composition were the main driver for the structuring of the macroinvertebrate taxonomic and functional assemblages during the dredging stages, whilst water environmental conditions dominated the taxonomic structure and dispersal processes determined the functional structure during the recovery stage. Implications of our results for monitoring and management of this activity in inland waters are discussed. (C) 2020 Elsevier Ltd. All rights reserved
Species range shifts in response to climate change and human pressure for the world's largest amphibian
No full textZebrafishprmt3negatively regulates antiviral responses
No full textArginine methylation catalyzed by protein arginine methyltransferases (PRMT) is a common post-translational modification in histone and nonhistone proteins, which regulates many cellular functions. Protein arginine methyltransferase 3 (prmt3), a type I arginine methyltransferase, has been shown to carry out the formation of stable monomethylarginine as an intermediate before the establishment of asymmetric dimethylarginine. To date, however, the role of PRMT3 in antiviral innate immunity has not been elucidated. This study showed that zebrafishprmt3was upregulated by virus infection and that the overexpression ofprmt3suppressed cellular antiviral response. The PRMT3 inhibitor, SGC707, enhanced antiviral capability. Consistently,prmt3-null zebrafish were more resistant to Spring Viremia of Carp Virus (SVCV) and Grass Carp Reovirus (GCRV) infection. Further assays showed that the overexpression ofprmt3diminished the phosphorylation of irf3 and prmt3 interacted with rig-i. In addition, both zinc-finger domain and catalytic domain of prmt3 were required for the suppressive function ofprmt3on IFN activation. Our findings suggested that zebrafishprmt3negatively regulated the antiviral responses, implicating the vital role ofprmt3-or even arginine methylation-in antiviral innate immunity
Integrative expression network analysis of microRNA and gene isoforms in sacred lotus
No full textBackground Gene expression is complex and regulated by multiple molecular mechanisms, such as miRNA-mediated gene inhibition and alternative-splicing of pre-mRNAs. However, the coordination of interaction between miRNAs with different splicing isoforms, and the change of splicing isoform in response to different cellular environments are largely unexplored in plants. In this study, we analyzed the miRNA and mRNA transcriptome from lotus (Nelumbo nucifera), an economically important flowering plant. Results Through RNA-seq analyses on miRNAs and their target genes (isoforms) among six lotus tissues, expression of most miRNAs seem to be negatively correlated with their targets and tend to be tissue-specific. Further, our results showed that preferential interactions between miRNAs and hub gene isoforms in one coexpression module which is highly correlated with leaf. Intriguingly, for many genes, their corresponding isoforms were assigned to different co-expressed modules, and they exhibited more divergent mRNA structures including presence and absence of miRNA binding sites, suggesting functional divergence for many isoforms is escalated by both structural and expression divergence. Further detailed functional enrichment analysis of miRNA targets revealed that miRNAs are involved in the regulation of lotus growth and development by regulating plant hormone-related pathway genes. Conclusions Taken together, our comprehensive analyses of miRNA and mRNA transcriptome elucidate the coordination of interaction between miRNAs and different splicing isoforms, and highlight the functional divergence of many transcript isoforms from the same locus in lotus
PGRL1 overexpression inPhaeodactylum tricornutuminhibits growth and reduces apparent PSII activity
No full textProton gradient regulation 5-like photosynthetic phenotype 1 (PGRL1)-dependent cyclic electron transport around photosystem I (PSI) plays important roles in the response to different stresses, including high light. Although the function of PGRL1 in higher plants and green algae has been thoroughly investigated, little information is available on the molecular mechanism of PGRL1 in diatoms. We created PGRL1 overexpression and knockdown transformants ofPhaeodactylum tricornutum, the diatom model species, and investigated the impact on growth and photosynthesis under constant and fluctuating light conditions. PGRL1 over-accumulation resulted in significant decreases in growth rate and apparent photosystem II (PSII) activity and led to an opposing change of apparent PSII activity when turning to high light, demonstrating a similar influence on photosynthesis as a PSII inhibitor. Our results suggested that PGRL1 overexpression can reduce the apparent efficiency of PSII and inhibit growth inP. tricornutum. These findings provide physiological evidence that the accumulation of PGRL1 mainly functions around PSII instead of PSI
Impacts of microdiet manufacturing technologies on the growth performance of large yellow croaker ( Pseudosciaena crocea ) larvae
No full textCrumbled feed (CF) is the most commonly used microdiet in the weaning phrase of large yellow croaker ( Pseudosciaena crocea ) in China. However, CF can be inefficient for local hatcheries due to its low water stability. In this study, we evaluated a more water -stable microdiet (micro -extrusion marumerization diet or MM) in comparison to the CF, and ascertained their effects on the growth of larval croaker. Our results showed that the MM (ca. 98% dry weight retained) was much more water -stable than the CF (only 76% dry weight retained) after 5 min vigorous aeration. This was especially true for the preservation of lipid content, 40% of which was lost from the CF. The remaining intact structure and nearly unchanged nutritional composition of the MM enabled greater fish growth performance after a 24 -day feeding trail, with 37% more dry weight gained than CF -fed larvae. Additionally, fish body compositions of each treatment directly reflected the nutritional profiles of each diet after aeration, and CF -fed fish had a significantly lower lipid content than those fed the MM (8.97 vs. 15.2%). Our results suggest that MM is a more suitable microdiet for the weaning phrase of croaker in hatcheries with vigorous aeration