Ammonium removal through anaerobic ammonium oxidation coupled to iron(III) reduction along the Yangtze river-estuary continuum.

Anaerobic ammonium oxidation coupled to iron(III) reduction (Feammox) process has recently been recognized as an important pathway for removing ammonium in various natural habitats. However, our understanding for Feammox in river-estuary continuum is limited. In this study, stable isotope tracers and high-throughput amplicon sequencing were employed to determine Feammox rates and identify associated microbial communities in sediments along the Yangtze river-estuary continuum.

Microbial nitrogen cycling in Microcystis colonies and its contribution to nitrogen removal in eutrophic Lake Taihu, China.

Cyanobacterial blooms induced by excessive loadings of nitrogen (N) and other nutrients are a severe ecological problem in aquatic ecosystems. Previous studies of N removal have primarily focused on sediment-water interface, yet the role of cyanobacterial colonies has recently been attracting more research attention. In this study, N cycling processes were quantified for cyanobacterial colonies (primarily Microcystis colonies) and their contribution to N removal was estimated for a large, shallow eutrophic lake in China, Lake Taihu.

Metabolic versatility of aerobic methane-oxidizing bacteria under anoxia in aquatic ecosystems.

The potential positive feedback between global aquatic deoxygenation and methane (CH) emission emphasizes the importance of understanding CH cycling under O-limited conditions. Increasing observations for aerobic CH-oxidizing bacteria (MOB) under anoxia have updated the prevailing paradigm that MOB are O-dependent; thus, clarification on the metabolic mechanisms of MOB under anoxia is critical and timely. Here, we mapped the global distribution of MOB under anoxic aquatic zones and summarized four underlying metabolic strategies for MOB under anoxia: (a) forming a consortium with oxygenic microorganisms; (b) self-generation/storage of O by MOB; (c) forming a consortium with non-oxygenic heterotrophic bacteria that use other electron acceptors; and (d) utilizing alternative electron acceptors other than O.

Phosphorus-driven regime shift from heterotrophic to autotrophic diazotrophs in a deep alpine lake.

Biological nitrogen fixation plays a critical role in maintaining primary production, particularly in systematic nitrogen deficiency. However, little is known about the dynamics within diazotrophic community facing ongoing nutrient enrichment in freshwater lakes. Here, a consecutive five-year investigation on diazotrophic community was conducted in Lake Fuxian, an oligotrophic deep alpine lake on the trajectory to eutrophic state.

N-containing dissolved organic matter promotes dissolved inorganic carbon supersaturation in the Yangtze River, China.

Dissolved inorganic carbon (DIC) represents a major global carbon pool and the flux from rivers to oceans has been observed to be increasing. The effect of weathering with respect to increasing DIC has been widely studied in recent decades; however, the influence of dissolved organic matter (DOM) on increasing DIC in large rivers remains unclear. This study employed stable carbon isotopes and Fourier transform ion cyclotron mass spectrometry (FT-ICR MS) to investigate the effect of the molecular composition of DOM on the DIC in the Yangtze River.

Short-term photodegradation of autochthonous and allochthonous dissolved organic matter in Lake Taihu, China.

Photochemistry is one of the key processes that shape the quality of dissolved organic matter (DOM) in aquatic systems, yet the photoreactivity of DOM from different sources remains largely unclear. In this study, DOM from 10 typical autochthonous and allochthonous sources in Lake Taihu basin were exposed to simulated sunlight, and quantitative and compositional changes of the DOM were explored by measuring its UV-Visable absorption and fluorescence spectroscopy. Photochemical release of nutrients was also explored during the incubations.

Higher allochthonous organic carbon increases polycyclic aromatic hydrocarbon concentration whereas fossil fuel combustion alters the composition: Evidence from a eutrophic plateau lake in southwest China.

Understanding the source of polycyclic aromatic hydrocarbons (PAHs) is crucial for determining their structural, degradational, and burial characteristics in lake sediments. Here, we used a sediment core to determine the changing sources and burial characteristics of 16 PAHs from Dianchi Lake, southwest China. The ∑PAH concentrations ranged from 105.

Anthropogenic Activities Generate High-Refractory Black Carbon along the Yangtze River Continuum.

Combustion-driven particulate black carbon (PBC) is a crucial slow-cycling pool in the organic carbon flux from rivers to oceans. Since the refractoriness of PBC stems from the association of non-homologous char and soot, the composition and source of char and soot must be considered when investigating riverine PBC. Samples along the Yangtze River continuum during different hydrological periods were collected in this study to investigate the association and asynchronous combustion drive of char and soot in PBC.

Hydrogenotrophic pathway dominates methanogenesis along the river-estuary continuum of the Yangtze River.

Rivers are considered as an important source of methane (CH) to the atmosphere, but our understanding for the methanogenic pathway in rivers and its linkage with CH emission is very limited. Here, we investigated the diffusive flux of CH and its stable carbon isotope signature (δC-CH) along the river-estuary continuum of the Yangtze River. The diffusive CH flux was estimated to 27.

Sandwich Plate Structure Periodically Attached by S-Shaped Oscillators for Low Frequency Ship Vibration Isolation.

Locally resonant phononic crystals are a kind of artificial periodic composite material/structure with an elastic wave band gap that show attractive application potential in low-frequency vibration control. For low-frequency vibration control problems of ship power systems, this paper proposes a phononic crystal board structure, and based on the Bloch theorem of periodic structure, it uses a finite element method to calculate the band structure and the displacement fields corresponding to the characteristic mode and vibration transmission curve of the corresponding finite periodic sandwich plate structure, and the band gap characteristics are studied. The mechanism of band gap formation is mainly attributed to the mode coupling of the phononic crystal plate structure.

Internal loop sustains cyanobacterial blooms in eutrophic lakes: Evidence from organic nitrogen and ammonium regeneration.

Algal bloom species can live upon internal regenerated ammonium (NH) for growth during the nitrogen-limited period. However, the linkages between NH regeneration and phytoplankton biomass and community composition dynamics remain largely unknown. To unravel the interactions between NH regeneration and phytoplankton community, we measured water column NH regeneration rates (REGs) during a continuous phytoplankton growing period and a contrast summer/winter turnover in eutrophic Lake Taihu.

Emerging role of dissolved organic nitrogen in supporting algal bloom persistence in Lake Taihu, China: Emphasis on internal transformations.

Dissolved organic nitrogen (DON) accounts for a significant fraction of the dissolved nitrogen (N) pool in eutrophic lakes, and substantial components of DON are available for phytoplankton. However, long-term changes in DON concentrations in eutrophic lakes have been poorly documented, and the particulate-related internal cycling of DON at the molecular level remains unclear. In this study, changes in the concentration of DON during the past 14 years of Lake Taihu, China were analyzed.

In-Depth Characterization of a Pro-Antibody-Drug Conjugate by LC-MS.

Pro-antibody-drug conjugate (PDC) is a hybrid structural format of immunoconjugate, where the structural complexity of pro-antibody and intrinsic heterogeneity of ADCs impose a prominent analytical challenge to the in-depth characterization of PDCs. In the present study, we successfully prepared and characterized PanP-DM1 as a model of PDCs, which is an anti-EGFR pro-antibody following conjugation with DM1 at lysine residues. The drug-to-antibody ratio (DAR) of PanP-DM1 was determined by LC-MS after deglycosylation, and verified by UV/vis spectroscopy.

Preparation and characterization of recombinant protein ScFv(CD11c)-TRP2 for tumor therapy from inclusion bodies in Escherichia coli.

Dendritic cells (DCs)-based immunotherapy represents an approach to the prevention and treatment of cancers. Targeting antigens to receptors on DCs can be expected to enhance immune response. We have constructed an expression vector pET32a(+)-ScFv(CD11c)-TRP2 based on a single-chain antibody fragment (ScFv) that targets the high affinity receptor CD11c which is expressed on murine DCs.

Preparation and characterization of fusion protein truncated Pseudomonas Exotoxin A (PE38KDEL) in Escherichia coli.

Pseudomonas Exotoxin A (PE) and truncated PE have been used to prepare immunotoxin with monoclonal antibodies. Truncated Pseudomonas Exotoxin A (PE38KDEL) was expressed with the pET-32a(+) vector in Escherichia coli under control of a T7 promoter. The recombinant protein was purified by His-Ni(2+) metal affinity chromatography and gel filtration.