Institute of Hydrobiology, Chinese Academy Of Sciences
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Remediation effect of Cr (VI)-contaminated soil by secondary pyrolysis oil-based drilling cuttings ash
No full textIn this study, secondary pyrolysis oil-based drilling cuttings ash (OBDCA-sp) was used to remediate chromium (Cr)-contaminated soil. The effects of the OBCDA-sp mesh, OBCDA-sp dosage and soil moisture content on the removal of Cr (VI) were investigated. Subsequently, a kinetic experiment was conducted where the pseudo-firstorder and pseudo-second-order kinetic models both fitted well on OBDCA-sp with the adsorption process of Cr (VI) in soil. The change of the chromium form indicated that the addition of OBCDA-sp transformed Cr from an effective state to a stable form, reducing its mobility and bioavailability. X-ray diffraction and Fourier transform infrared spectroscopy analysis were used to verify the potential mechanism of Cr (VI) removal; Ba, Fe, S, and P elements in OBCDA-sp were observed to play a significant role in the reduction of Cr (VI). The results from this study indicate that OBCDA-sp could be an emergent and promising alternative for the remediation of Cr-contaminated soil
Response of Vallisneria natans to aluminum phytotoxicity and their synergistic effect on nitrogen, phosphorus change in sediments
No full textIncreasing aluminum (Al) use and its effects on aquatic systems have been a global issue, however the Al impacts on submerged plants and their ecological functions were poorly understood. Aquatic simulation experiments were performed to study Al-toxicity on the germination and seedling morphological and physiological characteristics of Vallisneria natans, and investigate their synergistic effect on nitrogen (N), phosphorus (P) change and microbial community in sediment. The seeds germination characteristics, growth and physiological parameters of seedlings, including root activity, were significantly affected by alum treatments and the inhibition levels increased with Al3+ concentration. The Al accumulation in roots and leaves were significantly different. Al3+ concentration above 0.3 mg/L showed toxic to V. natans. TN, TP, IP, Fe/Al-P contents in sediments varied markedly under co-existence of Al and V. natans. Additionally, the relative abundance of sediment microbial community related to N, P cycle was effected. Results concluded that the increasing aquatic Al-concentration inhibits growth and propagation of submerged plants and the ecological restoration effect, and exerts synergistic effect with submerged plants on N, P components in sediments. Such findings were helpful for Al ecological evaluation, and were instructive for the submerged plants restoration in shallow eutrophic lakes with Al input
Novel Disinfection Byproducts Formed from the Pharmaceutical Gemfibrozil Are Bioaccumulative and Elicit Increased Toxicity Relative to the Parent Compound in Marine Polychaetes (Neanthes arenaceodentata)
No full textFormation of halogenated disinfection byproducts (DBPs) from pharmaceutically active compounds has been observed in water supply systems following wastewater chlorination. Although research has been limited thus far, several studies have shown that halogenated DBPs may elicit increased toxicity compared to their parent compounds. For example, the lipid regulator gemfibrozil has been shown to form chlorogemfibrozil (Cl-gemfibrozil) and bromogemfibrozil (Br-gemfibrozil) following chlorination, which are more potent antiandrogens in male Japanese medaka (Oryzias latipes) compared to their parent compounds. In the present study, we aimed to characterize the bioaccumulative ability of halogenated gemfibrozil DBPs in marine polychaetes via chronic sediment exposures and, consequently, to assess the chronic and acute toxicity of halogenated gemfibrozil DBPs through sediment (in vivo) and aqueous (in vivo and in silico) toxicity evaluations. Following 28 day sediment exposures, Cl-gemfibrozil and Br-gemfibrozil bioaccumulated within Neanthes arenaceodentata, with both compounds reducing survival and growth. The biota-sediment accumulation factors determined for Cl-gemfibrozil and Br-gemfibrozil were 2.59 and 6.86, respectively. Furthermore, aqueous 96 h toxicity tests with N. arenaceodentata indicated that gemfibrozil DBPs elicited increased toxicity compared to the parent compound. While gemfibrozil had an acute LC50 value of 469.85 +/- 0.096 mg/L, Cl-gemfibrozil and Br-gemfibrozil had LC50 values of 12.34 +/- 0.085 and 9.54 +/- 0.086 mg/L, respectively. Although acute toxicity is relatively low, our results indicate that halogenated gemfibrozil DBPs are bioaccumulative and may elicit effects in apex food web organisms prone to accumulation following lifelong exposures
Response of anatomy and CO2-concentrating mechanisms to variable CO2 in linear juvenile leaves of heterophyllous Ottelia alismoides: Comparisons with other leaf types
No full textOttelia alismoides (Hydrocharitaceae) is a heterophyllous freshwater macrophyte which shows heteroblastic heterophylly during plant development, and differs in carbon dioxide-concentrating mechanisms (CCMs) at different stage. This study investigated the anatomy and CCMs in the first stage of leaf during O. alismoides development, linear juvenile leaves. It comprised three layers of cell and enriched air spaces, but not significantly affected by CO2 concentration ([CO2]), while leaf thickness and chloroplast ultrastructure were significantly affected by [CO2]. The linear juvenile leaves could perform C-4 photosynthesis at low [CO2]; the two types of chloroplasts distributed in epidermal and mesophyll cells respectively, with different shape and starch content, might provide the structural basis for C-4 operation. The pH-drift data showed that the linear juvenile leaves could use HCO3- regardless of [CO2]. Whereas, CAM and C-4 operation could only be induced at low [CO2]. When compared the CCMs among all the heteromorphic leaves in O. alismoides, it is shown that CCMs in the O. alismoides heteromorphic leaves become more diversified during the plants development: HCO3- use was present in all leaf-types regardless of the [CO2]; CAM and C-4 were only induced at low [CO2] and became more efficient in mature leaves. The anatomy was also regulated to adapt to the functions of CCMs, and ultimately, the ovate mature leaves can operate C-4 constitutively
Deletion of narfl leads to increased oxidative stress mediated abnormal angiogenesis and digestive organ defects in zebrafish
No full textNuclear prelamin A recognition factor-like (NARFL) is a human protein that participates in cytosolic iron-sulfur (FeS) protein biogenesis and cellular defense against oxidative stress. Previous studies of Narfl knockout mice did not reveal well the regulatory mechanisms of embryonic development mediated by Narfl because the homozygous mice die in utero. Here, we investigated the function of narfl in an established zebrafish knockout model by taking advantage of zebrafish external fertilization and ease of embryonic development examination. Our experiments showed that narfl deletion resulted in larvae lethality, subintestinal vessel (SIV) malformation and digestive organ defects in the early stages of embryonic development. Biochemical analyses and western blot revealed increased oxidative stress and upregulated hypoxia-inducible factor-1 alpha (HIF-1 alpha) expression in narfl(-/-) fish. The use of HIF-1 alpha inhibitor 2-methoxyestradiol (2ME2) for the treatment of mutants partially rescued the SIV sprouting. These results suggest that narfl deletion causes increased oxidative stress and subintestinal vessel malformation, which further influence the development of digestive organs and might contribute to the lethality of the narfl knockout fish
Life history of Ephemera wuchowensis Hsu, 1937 (Ephemeroptera: Ephemeridae) in a northern subtropical stream in Central China
No full textEphemera wuchowensis Hsu, 1937 is a commonly encountered and widely distributed burrowing mayfly species in China, but its biological traits are poorly understood. In this study, we investigated the life history of E. wuchowensis using the size-frequency method at three sites along a creek in Central China. Monthly samples of larvae were taken from January to December 2017. The life history of E. wuchowensis was found to be univoltine in this northern subtropical region, and there were no significant differences among the sites based on the size-frequency histograms. Unlike the emergence of congeneric species, which inhabit southern subtropical monsoon streams and are showed to be highly synchronised with a relatively short flight period, the adults of E. wuchowensis has a long emergence period from April to September with two distinct peaks of emergence: the first from April to June, and the second from August to September
Stable Genome Incorporation of Sperm-derived DNA Fragments in Gynogenetic Clone of Gibel Carp
No full textHow unisexual animals eliminate deleterious mutations to avoid dead ends is one of the most interesting puzzles in evolutionary genetics. Incorporation of microchromosomes derived from exogenous sperm had been observed in gynogenetic animals, but little is known about their detailed process and hereditary fate. Here, we show a stable genome incorporation case in an artificial clone F of gynogenetic gibel carp (Carassius gibelio). A total of 12 exogenous DNA fragments were screened through a read depth-dependent comparison strategy and confirmed to be specific to the clone F and the paternal blunt snout bream (Megalobrama amblycephala Yin) by SCAR (sequence characterized amplified regions) marker detection. Moreover, these sperm-derived DNA fragments were not detected in some samples in early gynogenetic generations, but they were found to exist in all examined individuals through artificial gynogenetic selections of 13 generations, implying that they might have stably incorporated into the genome of clone F. Furthermore, chromosome localization and sequence characterization indicate that the largest fragment CgA22_34 is derived from blunt snout bream non-LTR retrotransposon and durably incorporated into only one of three homologous chromosomes of gibel carp clone F. Our results suggest that the incorporated sperm-derived DNA fragments by allogynogenesis should increase genetic diversity and introduce new traits into unisexual animals which will benefit genetic breeding of gibel carp. During the process, transposable elements (TEs) may play significant roles in shaping the genome structures. Simultaneously, the incorporated DNA fragments are able to be used as genetic markers to perform selective breeding programs in aquaculture practices of gibel carp.</p
PhyloSuite: An integrated and scalable desktop platform for streamlined molecular sequence data management and evolutionary phylogenetics studies
No full textMultigene and genomic data sets have become commonplace in the field of phylogenetics, but many existing tools are not designed for such data sets, which often makes the analysis time-consuming and tedious. Here, we present PhyloSuite, a (cross-platform, open-source, stand-alone Python graphical user interface) user-friendly workflow desktop platform dedicated to streamlining molecular sequence data management and evolutionary phylogenetics studies. It uses a plugin-based system that integrates several phylogenetic and bioinformatic tools, thereby streamlining the entire procedure, from data acquisition to phylogenetic tree annotation (in combination with iTOL). It has the following features: (a) point-and-click and drag-and-drop graphical user interface; (b) a workplace to manage and organize molecular sequence data and results of analyses; (c) GenBank entry extraction and comparative statistics; and (d) a phylogenetic workflow with batch processing capability, comprising sequence alignment (mafft and macse), alignment optimization (trimAl, HmmCleaner and Gblocks), data set concatenation, best partitioning scheme and best evolutionary model selection (PartitionFinder and modelfinder), and phylogenetic inference (MrBayes and iq-tree). PhyloSuite is designed for both beginners and experienced researchers, allowing the former to quick-start their way into phylogenetic analysis, and the latter to conduct, store and manage their work in a streamlined way, and spend more time investigating scientific questions instead of wasting it on transferring files from one software program to another.</p
Molecular phylogenetics and mitogenomics of three avian dicrocoeliids (Digenea: Dicrocoeliidae) and comparison with mammalian dicrocoeliids
No full textBackgroundThe Dicrocoeliidae are digenetic trematodes mostly parasitic in the bile ducts and gall bladder of various avian and mammalian hosts. Until recently their systematics was based on morphological data only. Due to the high morphological uniformity across multiple dicrocoeliid taxa and insufficient knowledge of relative systematic value of traditionally used morphological characters, their taxonomy has always been unstable. Therefore, DNA sequence data provide a critical independent source of characters for phylogenetic inference and improvement of the system.MethodsWe examined the phylogenetic affinities of three avian dicrocoeliids representing the genera Brachylecithum, Brachydistomum and Lyperosomum, using partial sequences of the nuclear large ribosomal subunit (28S) RNA gene. We also sequenced the complete or nearly complete mitogenomes of these three isolates and conducted a comparative mitogenomic analysis with the previously available mitogenomes from three mammalian dicrocoeliids (from 2 different genera) and examined the phylogenetic position of the family Dicrocoeliidae within the order Plagiorchiida based on concatenated nucleotide sequences of all mitochondrial genes (except trnG and trnE).ResultsCombined nucleotide diversity, Kimura-2-parameter distance, non-synonymous/synonymous substitutions ratio and average sequence identity analyses consistently demonstrated that cox1, cytb, nad1 and two rRNAs were the most conserved and atp6, nad5, nad3 and nad2 were the most variable genes across dicrocoeliid mitogenomes. Phylogenetic analyses based on mtDNA sequences did not support the close relatedness of the Paragonimidae and Dicrocoeliidae and suggested non-monophyly of the Gorgoderoidea as currently recognized.ConclusionsOur results show that fast-evolving mitochondrial genes atp6, nad5 and nad3 would be better markers than slow-evolving genes cox1 and nad1 for species discrimination and population level studies in the Dicrocoeliidae. Furthermore, the Dicrocoeliidae being outside of the clade containing other xiphidiatan trematodes suggests a need for the re-evaluation of the taxonomic content of the Xiphidiata
Benthic-pelagic coupling in lake energetic food webs
No full textUnderstanding how energy and matter flow among habitats is a central issue in ecology. In lake ecosystems, benthic-pelagic coupling (B-P coupling) was mainly studied based on the diets of top consumers at a population level or through food chains. However, how B-P coupling operates at the ecosystem level is largely unknown. In the present study, we revealed B-P coupling within an energetic food web framework, combining stable isotope analyses and mass balanced model. We constructed the energetic food webs of two large shallow lakes of different trophic status based on field survey data. We also defined benthic and pelagic components based on the proportion of consumer energy uptake from phytoplankton (benthic: < 50%; pelagic: > 50%; benthivore: < 20%; planktivore: > 80%; coupler: 20-80%) and quantified the energy flux through B-P coupling in the two lake food webs. The total consumption was estimated to be 699 t/km(2)/y in Lake Erhai (mesoeutrophic lake) and 2094 t/km(2)/y in Lake Dianchi (hypereutrophic lake), and the B-P coupling energy was 405 t/km(2)/y and 213 t/km(2)/y, re-spectively. In these lakes, B-P coupling occurred on multiple trophic levels; lower trophic level consumers contributed the largest proportion (90% and 98%), while top consumers were of limited importance; most coupling links were weak, and energy exchange was highly asymmetric with the total amount of energy exported from benthic part to pelagic part being over 4 folds of the counter flux. The quantity and pattern of B-P coupling vary between the mesoeutrophic and hypereutrophic lakes. In terms of energy flux per unit area, the total system throughput in the mesoeutrophic lake (Lake Erhai) was 3.73 times of that in the hypereutrophic lake (Lake Dianchi), while the proportion of coupling energy was much lower in the former (19%) than the latter (31%). A greater energy flux through pelagic-to-benthic pathways was found in the hypereutrophic lake, and most of the coupling energy was contributed by consumers at higher trophic levels. Besides, the coupling strength was stronger in the hypereutrophic than the mesoeutrophic lake. We showed for the first time how B-P coupling operates in lake energetic food webs. Our results provided new insights into understanding the energy flux through B-P coupling of lake ecosystems, and how such coupling could be changed by environmental disturbances. We also provided a new approach to reveal habitat coupling within an energetic food web framework.</p