Institute of Hydrobiology, Chinese Academy Of Sciences
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Ultrastructural description and phylogeny of a novel microsporidian, Glugea eda n. sp. from the striated fusilier, Caesio striata, in the Red Sea off Saudi Arabia
No full textGlugea eda n. sp. is described from the mesenteries of the striated fusilier, Caesio striata, collected from the Red Sea coast off Yanbu' al Bahr, Saudi Arabia. Numerous blackish xenomas, ranged from 3 to 5 mm, were found in the body cavity associated with the mesenteries. Mature spores are monomorphic, ellipsoidal with an average size of 5(4-6) mu m in length and 2.2 (2-3) mu m in width. Observations of the ultrastructure revealed that the development was asynchronous and that the nuclei were isolated throughout the life cycle with uninucleate meronts. Sporoblasts were uninucleated and existed together with sporonts in a fully formed parasitophorous vacuole. The polar filament of the mature spore was isofilar with 24-28 coils, arranged in three rows. Phylogenetic analysis placed the current microsporidia within the clade grouping Glugea species and close to the species described from the Red Sea and Arabian Gulf. The morphometric and molecular comparison with other members of the genus Glugea evidenced the taxonomic novelty of the present form, suggesting that it should be considered as a new species. To the best of our knowledge, the parasite here described represents the first occurrence of microsporidian infection in the fish of the family Caesionidae.</p
Community metagenomic assembly reveals microbes that contribute to the vertical stratification of nitrogen cycling in an aquaculture pond
No full textThe identities and functional capacities of the microbial populations within surface water (SW), bottom water (BW), surface sediment (SS) and deep sediment (DS) samples from a typical grass carp (Ctenopharyngodon idellus) culturing pond in central China were explored using metagenomics. In total, the community structure and microbial processes of the water columns was distinct from that of the SS and DS layers. Alphaproteobacteria, Actinobacteria, Cyanobacteria and Planctomycetes were abundant in the water, while Deltaproteobacteria, Gammaproteobacteria, Euryarchaeota (Archaea) and Nitrospirae were more abundant in the sediment (P < .05). The functional potential and microorganisms responsible for the N nutrient cycles were also reconstructed in silico. The high functional potential for N assimilation, protein synthesis and cell proliferation in pond water should be responsible for low ammonia concentration detected. Ammonia oxidation functional genes were present in very low abundances, and were mostly detected in the water columns and related to Nitrosomonas (100%). Denitrification were observed mostly in SS and the main taxon involved was Rhodocyclales. The potential for N fixation (nif genes) and dissimilatory nitrate reduction to ammonium was also observed mostly in sediment, which is a disadvantage for ammonia reduction in the pond ecosystem. Overall, these results offer a more detailed perspective on the microbial functional ecology of the aquaculture pond
Improving methane production from algal sludge based anaerobic digestion by co-pretreatment with ultrasound and zero-valent iron
No full textResource recovery using algal sludge harvested from algal bloom has aroused broad interest. The present study investigated the methane production potential of algal sludge subjected to co-pretreatment with zero-valent iron and ultrasound. Results indicated that the combined zero-valent iron and ultrasound pretreatments induce algal cell wall disruption. Chlorophyll-a concentrations decreased by 14.17%, 25.20%, 35.77%, 45.05%, 61.07%, and 71.52% at zero-valent iron concentrations of 0,1, 2, 5,10, and 20 g of zero-valent iron/g of total solid, respectively, after ultrasound treatment for 30 min. Soluble chemical oxygen demands increased 5.22, 8.51, 9.85, 5.52, 11.94, and 9.40 times of corresponding original levels, respectively. After anaerobic digestion for 37 days, accumulative methane production was 30.39, 37.11, 38.06, 42.52, 49.27, 48.93, and 60.84 L CH4/kg total chemical oxygen demand of algae in Reactors R1-R7, respectively. Methane production constantly increased with zero-valent iron dosage, and the highest methane production was achieved at 20 g of zero-valent iron/g of algal total solid. Methane production in all conditions tested fitted to the one-substrate model. Model analysis indicated that hydrolysis coefficient and the dewaterability of algae increased with zero-valent iron dosage. The present study indicated that a pretreatment method combining zero-valent iron and ultrasound may be developed as an effective resource recovery technology for algal sludge treatment. (C) 2020 Elsevier Ltd. All rights reserved
TET is targeted for proteasomal degradation by the PHD-pVHL pathway to reduce DNA hydroxymethylation
No full textHypoxia-inducible factors are heterodimeric transcription factors that play a crucial role in a cell's ability to adapt to low oxygen. The von Hippel-Lindau tumor suppressor (pVHL) acts as a master regulator of HIF activity, and its targeting of prolyl hydroxylated HIF-alpha for proteasomal degradation under normoxia is thought to be a major mechanism for pVHL tumor suppression and cellular response to oxygen. Whether pVHL regulates other targets through a similar mechanism is largely unknown. Here, we identify TET2/3 as novel targets of pVHL. pVHL induces proteasomal degradation of TET2/3, resulting in reduced global 5-hydroxymethylcytosine levels. Conserved proline residues within the LAP/LAP-like motifs of these two proteins are hydroxylated by the prolyl hydroxylase enzymes (PHD2/EGLN1 and PHD3/EGLN3), which is prerequisite for pVHL-mediated degradation. Using zebrafish as a model, we determined that global 5-hydroxymethylcytosine levels are enhanced in vhl-null, egln1a/b-double-null, and egln3-null embryos. Therefore, we reveal a novel function for the PHD-pVHL pathway in regulating TET protein stability and activity. These data extend our understanding of how TET proteins are regulated and provide new insight into the mechanisms of pVHL in tumor suppression
An Indo-Pacific Humpback Dolphin Genome Reveals Insights into Chromosome Evolution and the Demography of a Vulnerable Species
No full textThe Indo-Pacific humpback dolphin (Sousa chinensis) is a small inshore species of odontocete cetacean listed as Vulnerable on the IUCN Red List. Here, we report on the evolution of S. chinensis chromosomes from its cetruminant ancestor and elucidate the evolutionary history and population genetics of two neighboring S. chinensis populations. We found that breakpoints in ancestral chromosomes leading to S. chinensis could have affected the function of genes related to kidney filtration, body development, and immunity. Resequencing of individuals from two neighboring populations in the northwestern South China Sea, Leizhou Bay and Sanniang Bay, revealed genetic differentiation, low diversity, and small contemporary effective population sizes. Demographic analyses showed a marked decrease in the population size of the two investigated populations over the last similar to 4,000 years, possibly related to climatic oscillations. This study implies a high risk of extinction and strong conservation requirement for the Indo-Pacific humpback dolphin
Ontogeny and Phylogeny of a New Hypotrichous Ciliate (Protista, Ciliophora), Metaurostylopsis alrasheidi n. sp., With Establishment of a New Genus Monourostylopsis n. gen
No full textIn the present study, based on both morphologic and phylogenetic analyses, a new genus, Monourostylopsis n. gen., and new species, Metaurostylopsis alrasheidi n. sp. as well as a new combination, Monourostylopsis antarctica (Jung et al., 2011) n. comb. (original combination: Metaurostylopsis antarctica Jung et al., 2011), are suggested. The new genus is diagnosed mainly by having three or more frontoterminal cirri, a midventral complex with midventral pairs and a single midventral row, one right marginal row and two or more left marginal rows. The new genus can be easily separated from the morphologically similar genera mainly by having single right marginal row (vs. two or more right marginal rows). Based on live observation and protargol staining, the morphology and morphogenesis of a new species, M. alrasheidi n. sp. isolated from China, were investigated. The new species can be characterized by: two types of cortical granules; about 22 adoral membranelles; three or four frontoterminal, four or five transverse cirri; about eight midventral pairs and a midventral row of three or four unpaired midventral cirri; three or four left and right marginal rows. The main morphogenetic features of Metaurostylopsis alrasheidi n. sp. can be summarized as: (1) the entire parental ciliature, including the oral apparatus, is renewed; (2) the oral primordium of the proter probably originates within a pouch; (3) the oral primordium of the opisthe forms de novo on the cell surface; (4) the anlagen of marginal rows and dorsal kineties are formed intrakinetally, and (5) the fusion of macronuclear nodules results in an irregular branched mass prior to karyokinesis. In the phylogenetic trees, all the available Metaurostylopsis sequences cluster together in a clade with full support (ML/BI: 100/1.00) revealing that the genus is monophyletic within the large group of core urostylids
Healthy waterways and ecologically sustainable cities in Beijing-Tianjin-Hebei urban agglomeration (northern China): Challenges and future directions
No full textThe cities across the northern dry region of China are exposed to multiple sustainability challenges. Beijing-Hebei-Tianjin (BTH) urban agglomeration, for example, experiences severe water shortages due to rapidly expanding urban populations, industrial use, and irrigation-intensive agriculture. Climate change has further threatened water resources security. Overuse of water resources to meet the demand of various water sectors has far-reaching health and environmental implications including ecosystem sustainability. Surface water and groundwater pollution present public health risks. Despite the extraordinary policies and efforts being made and implemented by the Government of China, the BTH region currently lacks coordination among stakeholders leading to poor water governance. Consultation among scientists, engineers and stakeholders on regional water security issues is crucial and must be frequent and inclusive. An international symposium was held in Shijiazhuang in early November 2019 to identify some of the key water security challenges and scope of an idealized future eco-city in the region by developing a sustainability framework. This work drew on experiences from across China and beyond. Scientists agree that integration of science, technology, and governance within an appropriate policy framework was particularly significant for combating the issue of water insecurity, including in the region's newly developed city, Xiong'an New Area. An emerging concept, "Healthy Waterways and Ecologically Sustainable Cities" which integrates social, ecological and hydrological systems and acts as an important pathway for sustainability in the 21st century was proposed in the symposium to tackle the problems in the region. This high level biophysical and cultural concept empowers development goals and promotes human health and wellbeing. The framework on healthy waterways and ecologically sustainable cities can overcome sustainability challenges by resolving water resource management issues in BTH in a holistic way. To implement the concept, we strongly recommend the utilization of evidence-based scientific research and institutional cooperation including national and international collaborations to achieve the Healthy Waterways and Ecologically Sustainable Cities goal in the BTH in future
Resource utilization of secondary pyrolysis oil-based drilling cuttings ash for removing Cr (VI) contaminants: Adsorption properties, kinetics and mechanism
No full textSecondary pyrolysis oil-based drilling cuttings ash (OBCDA-sp) was employed as a new absorbing material to remove Cr (VI) in wastewater. Varying factors, including pH value, dosage of OBCDA-sp, reaction time and original Cr (VI) contents were studied to investigate the Cr (VI) removal efficiency. Elovich and Pseudo-secondorder models were fitted well with the adsorption kinetics process. In addition, the Langmuir model was well employed to fit Cr (VI) adsorption isotherm on OBCDA-sp. The calculated Cr (VI) theoretic adsorption quantity of OBCDA-sp was 48 mg/g. XPS, SEM-EDS, FTIR and XRD were used to characterize the physicochemical properties of OBDCA-sp. The result shows that the complex process of the Cr (VI) removal involves physical and chemical adsorption, and co-precipitation and reduction. Ba, Fe, S and P element onto OBCDA-sp surface have exerted significant role in Cr (VI) removal