Key Laboratory of Marine Chemical Theory and Technology

Qingdao, China

Key Laboratory of Marine Chemical Theory and Technology

Qingdao, China
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Wang H.,Ocean University of China | Wang H.,CAS Qingdao Institute of Oceanology | Mi T.,CAS Qingdao Institute of Oceanology | Mi T.,Ocean University of China | And 8 more authors.
Journal of Plankton Research | Year: 2017

Diatoms comprise up to 40% of annual productivity in the modern ocean, and some stress factors may alter their physiology and survival. Here, we describe the morphological, biochemical and molecular responses that occur during metacaspase-mediated programmed cell death (PCD) in response to silicate limitation in the ubiquitous diatom Skeletonema marinoi. Transmission electron microscopy revealed that vacuolization occurred while the plasma membranes remained intact. Caspase 3-like activity, antioxidant gene expression, phosphatidylserine externalization and activated caspase-like expression were measured using in vivo staining. The results show that each was significantly increased under silicate limitation conditions. Using quantitative reverse transcription-PCR, we identified six distinct putative metacaspase proteins in S. marinoi, and we show that each contains a conserved caspase-like domain and is differentially expressed and that some of their expression profiles were correlated with PCD. Silicate limitation could trigger PCD in S. marinoi as well as an increase of antioxidant genes. PCD could be employed as a strategy to decrease silicate demand of the whole population and probably regulate the fate of S. marinoi. © The Author 2017. Published by Oxford University Press. All rights reserved.


He H.,Ocean University of China | Zhen Y.,CAS Qingdao Institute of Oceanology | Mi T.,CAS Qingdao Institute of Oceanology | Yu Z.,Key Laboratory of Marine Chemical Theory and Technology
Acta Oceanologica Sinica | Year: 2015

Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Seasonal and spatial distribution of ammonia-oxidizing archaea (AOA) and betaproteobacteria (β-AOB) in surface sediments from the East China Sea (ECS) were investigated using ammonia monooxygenase α subunit (amoA) gene. In order to characterize the community of AOA and β-AOB, real-time quantitative polymerase chain reaction (qPCR) was carried out in this study, along with environmental parameters. The abundance of β-AOB amoA gene (2.17×106–4.54×107 copy numbers per gram wet weight sediment) was always greater than that of AOA amoA gene (2.18×105–9.89×106 copy numbers per gram wet weight sediment) in all sampling stations. The qPCR results were correlated with environmental parameters. AOA amoA gene copy numbers in April were positively related to temperature and nitrite concentration (ρ<0.05). β-AOB amoA gene copy numbers in August correlated negatively with salinity (ρ<0.01), and correlated positively with ammonium concentration (ρ<0.05). With the increase of salinity, the amoA gene copy ratio of AOB to AOA had a tendency to decrease, which suggested β-AOB dominated in the area of high level ammonium and AOA preferred high salinity area. © 2015, The Chinese Society of Oceanography and Springer-Verlag Berlin Heidelberg.


He H.,Ocean University of China | Zhen Y.,Ocean University of China | Zhen Y.,CAS Qingdao Institute of Oceanology | Mi T.,Ocean University of China | And 4 more authors.
Geomicrobiology Journal | Year: 2016

Community composition and abundance of ammonia-oxidizing archaea (AOA) were investigated using ammonia monooxygenase α subunit (amoA) in sediments from the Changjiang estuary and its adjacent area in the East China Sea (ECS). Real-time quantitative polymerase chain reaction (qPCR), clone libraries and sequencing were performed to characterize the AOA community. Clone libraries analysis showed that the majority of amoA sequences fell within the Nitrosopumilus cluster. Correlation analysis showed that AOA diversity was closely related to the nitrite concentration, which was consistent with the canonical correspondence analysis (CCA) where a significant association between nitrite and AOA community composition was observed. The qPCR results were found to be significantly correlated with the environmental parameters. In the gravity cores, a significant positive correlation was found between ammonium concentrations and amoA gene copy numbers from different sediment depths at station S31. At station S33, however, ammonium concentration had a negative correlation and nitrite concentration had a positive correlation with amoA gene copy numbers. In the surface sediments, chlorophyll a concentration had a negative correlation and nitrate concentration had a positive correlation with amoA gene copy numbers. Compared amoA gene copy numbers from AOA with those from ammonia-oxidizing β-proteobacteria (β-AOB) in the same studied areas, the amoA gene copy ratio of β-AOB to AOA was negatively correlated with the phosphate concentration and dissolved oxygen concentration, but was not significantly correlated with either ammonium concentrations or salinity. Our data provided valuable information to achieve a better understanding of the potential role of ammonia oxidizers at the interface between terrestrial and marine environments. © 2016 Taylor & Francis Group, LLC


Zhang Y.,Ocean University of China | Zhang Y.,CAS Qingdao Institute of Oceanology | Zhen Y.,Ocean University of China | Zhen Y.,CAS Qingdao Institute of Oceanology | And 5 more authors.
Journal of Ocean University of China | Year: 2016

Sulfate-reducing bacteria (SRB), which obtain energy from dissimilatory sulfate reduction, play a vital role in the carbon and sulfur cycles. The dissimilatory sulfite reductase (Dsr), catalyzing the last step in the sulfate reduction pathway, has been found in all known SRB that have been tested so far. In this study, the diversity of SRB was investigated in the surface sediments from the adjacent area of Changjiang Estuary by PCR amplification, cloning and sequencing of the dissimilatory sulfite reductase beta subunit gene (dsrB). Based on dsrB clone libraries constructed in this study, diversified SRB were found, represented by 173 unique OTUs. Certain cloned sequences were associated with Desulfobacteraceae, Desulfobulbaceae, and a large fraction (60%) of novel sequences that have deeply branched groups in the dsrB tree, indicating that novel SRB inhabit the surface sediments. In addition, correlations of the SRB assemblages with environmental factors were analyzed by the linear model-based redundancy analysis (RDA). The result revealed that temperature, salinity and the content of TOC were most closely correlated with the SRB communities. More information on SRB community was obtained by applying the utility of UniFrac to published dsrB gene sequences from this study and other 9 different kinds of marine environments. The results demonstrated that there were highly similar SRB genotypes in the marine and estuarine sediments, and that geographic positions and environmental factors influenced the SRB community distribution. © 2016, Science Press, Ocean University of China and Springer-Verlag Berlin Heidelberg.


Qiao L.,Ocean University of China | Qiao L.,CAS Qingdao Institute of Oceanology | Chen Y.,Xiamen University | Mi T.,Ocean University of China | And 6 more authors.
Journal of Applied Phycology | Year: 2016

Brown tides caused by the excessive growth of the pelagophyte Aureococcus anophagefferens have occurred frequently in Qinhuangdao, China, since 2009. In this study, the temporal and spatial variations of A. anophagefferens and Minutocellus polymorphus were analyzed using real-time fluorescent quantitative PCR. The relationship between nutrient contents and brown tide events as well as the impacts of the brown tides on the composition of phytoplankton is discussed. The results showed that A. anophagefferens reached peak densities in July. Brown tides occurred in the coastal waters of Funing and Changli, and the main affected areas shifted from south to north throughout the experiment. The A. anophagefferens brown tide event was not monospecific, as M. polymorphus and Prorocentrum minimum were also observed. A redundancy analysis (RDA) indicated that decreasing concentrations of dissolved inorganic nitrogen (DIN) and increasing concentrations of the available organic nitrogen compounds (urea, dissolved free amino acids (DFAA), and dissolved combined amino acids (DCAA)) from March to June may have resulted in the outbreak of the brown bloom of A. anophagefferens, coinciding with a reduction in the community diversity of phytoplankton in the coastal waters of Qinhuangdao. © 2016 Springer Science+Business Media Dordrecht


He H.,Ocean University of China | Zhen Y.,Ocean University of China | Zhen Y.,CAS Qingdao Institute of Oceanology | Mi T.,Ocean University of China | And 7 more authors.
Estuarine, Coastal and Shelf Science | Year: 2015

Sulfate- and sulfite-reducing prokaryotes (SSRP) communities play a vital role in both sulfur and carbon cycles. Community composition and abundance of SSRP were investigated using dissimilatory sulfite reductase β subunit (dsrB) gene sequencing in sediments from the Changjiang estuary and its adjacent area in the East China Sea (ECS). Clone libraries were constructed and real-time fluorescence quantitative polymerase chain reaction (qPCR) was applied to understand the community information of SSRP. In addition to sequences affiliated to sulfate-reducing prokaryotes (SRP), those affiliated with sulfite-reducing prokaryotes (SiRP) were also observed. Four phylotypes of SRP in this study showed genetic similarity to Desulfobulbaceae, Syntrophobacteraceae, Desulfobacteraceae and Peptococcaceae, and an unknown group that could not be clearly affiliated with known lineages was found. Salinity, temperature and contents of total organic carbon (TOC) were most closely correlated with the SSRP communities by canonical correspondence analysis (CCA). 210Pb activities demonstrated the sedimentary environment at S33 was more stable than that at S31. Intense resuspension and reconstruction of sediments made the vertical abundance profile of SSRP fluctuate violently. For surface sediments, the dsrB gene copy numbers near the Changjiang estuary were higher than those in the mouth of Hangzhou Bay and the mud deposits along the Zhejiang coast, and contents of TOC were positively related to the copy numbers of dsrB gene. Our data provided valuable information to achieve a better understanding of the potential role of SSRP in sediments from the Changjiang estuary and adjacent East China Sea. © 2015.

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