Titanium dioxide nanoparticles (TiO2 NPs) are one of the most widely used nanomaterials in the consumer products, agriculture, and energy sectors. Their large demand and widespread applications will ...inevitably cause damage to organisms and ecosystems. A better understanding of TiO2 NP toxicity in living organisms may promote risk assessment and safe use practices of these nanomaterials. This review summarizes the toxic effects of TiO2 NPs on multiple taxa of microorganisms, algae, plants, invertebrates, and vertebrates. The mechanism of TiO2 NP toxicity to organisms can be outlined in three aspects: The Reactive Oxygen Species (ROS) produced by TiO2 NPs following the induction of electron–hole pairs; cell wall damage and lipid peroxidation of the cell membrane caused by NP-cell attachment by electrostatic force owing to the large surface area of TiO2 NPs; and TiO2 NP attachment to intracellular organelles and biological macromolecules following damage to the cell membranes.
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•eDNA can well recover biodiversity and spatial distribution in rivers.•Both net tow and eDNA recovered similar factors for biodiversity spatial distribution.•Inconsistency was detected at lower ...taxonomic levels in several taxa.•Capturing capacity, eDNA persistence, and biological features likely drove the disparities.•eDNA-metabarcoding is recommended for studying plankton-community interactions.
Human societal development has caused rapid degradation of freshwater ecosystems, resulting in significant biodiversity decline globally. The conservation of aquatic ecosystems, particularly the management of biodiversity in urban areas, has become an increasingly significant issue for ensuring the sustainability of these ecosystems. The restoration of degraded aquatic ecosystems relies on a comprehensive understanding of the interactions between biological communities and multiple stressors derived from human activities. Environmental DNA (eDNA)-based methods have emerged as effective tools for dissecting complex community-environment interactions. Nevertheless, potential causes for technical disparities and conclusions drawn from conventional sampling versus eDNA-based methods remain inadequately evaluated. In this study, we conducted a comprehensive survey of plankton communities along the environmental gradient of the North Canal River in Northern China to assess causes and consequences for any disparities between conventional plankton net tow and eDNA sampling for metabarcoding-based analysis of plankton-environment interactions. Our findings demonstrated that eDNA-metabarcoding was effective for characterizing both biodiversity and geographical distribution. Both methods exhibited general consistency in elucidating community structure and identifying the key environmental factors influencing geographical distribution of both zooplankton and phytoplankton. As we explored lower taxonomic ranks, we found inconsistent patterns at certain levels (e.g., phylum or order) within some taxa (e.g., Bacillariophyta and Rotifera), even substantial variability for several taxonomic groups (e.g., Euglenozoa and Apicomplexa). The varied environmental prevalence and persistence of eDNA, biological and ecological characteristics of diverse taxa in plankton, and sampling efficiency of both methods likely contributed to the observed disparities. Given its higher biodiversity recovery capacity, efficiency, sampling convenience, and capability to identify influential factors driving the geographical distribution of biodiversity, eDNA-based metabarcoding is recommended for studying plankton-environment interactions, particularly in studies involving a large number of samples at extended geographical scales.
The shells of pearl oysters, Pinctada fucata, are composed of calcite and aragonite and possess remarkable mechanical properties. These shells are formed under the regulation of macromolecules, ...especially shell matrix proteins (SMPs). Identification of diverse SMPs will lay a foundation for understanding biomineralization process. Here, we identified 72 unique SMPs using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of proteins extracted from the shells of P. fucata combined with a draft genome. Of 72 SMPs, 17 SMPs are related to both the prismatic and nacreous layers. Moreover, according to the diverse domains found in the SMPs, we hypothesize that in addition to controlling CaCO3 crystallization and crystal organization, these proteins may potentially regulate the extracellular microenvironment and communicate between cells and the extracellular matrix (ECM). Immunohistological localization techniques identify the SMPs in the mantle, shells and synthetic calcite. Together, these proteomic data increase the repertoires of the shell matrix proteins in P. fucata and suggest that shell formation in P. fucata may involve tight regulation of cellular activities and the extracellular microenvironment.
In bivalves, the mantle tissue secretes organic matrix and inorganic ions into the extrapallial space (EPS) to form the shells. In addition, more and more evidences indicate the participation of ...hemocytes in shell mineralization, but no direct evidence has been reported that verifies the presence of hemocytes in the EPS, and their exact roles in biomineralization remain uncertain. Here, we identified hemocytes from the EPS of Pinctada fucata. Numerous components involved in cellular and humoral immunity were identified by proteome analysis, together with several proteins involved in calcium metabolism. The hemocytes exerted active phagocytosis and significantly upregulated the expression of immune genes after immune stimulation. A group of granulocytes were found to contain numerous calcium-rich vesicles and crystals, which serve as a calcium pool. During shell regeneration, some genes involved in calcium metabolism are upregulated. Strikingly, most of the shell matrix proteins were absent in the hemocytes, suggesting that they might not be solely responsible for directing the growth of the shell. Taken together, our results provided comprehensive information about the function of hemocytes in immunity and shell formation.
Pretricuspid shunts have been associated with poorer survival rates in patients with Eisenmenger syndrome compared with postricuspid shunts and complex lesions. However, the risk stratification for ...persistent pulmonary hypertension (PH) in this population remains uncertain.
We retrospectively enrolled 103 patients with pretricuspid shunts with high total pulmonary resistance >4.5 Wood units (estimated pulmonary vascular resistance ≥3 Wood units). During a mean±SD follow-up of 20.95±24.84 months, 32 patients developed postoperative persistent PH after shunt correction. We identified 3 significant predictors of postoperative persistent PH, including mean pulmonary artery pressure after inhaled oxygen ≥40.5 mm Hg (odds ratio OR, 7.78 95% CI, 2.02-30.03;
<0.01), total pulmonary resistance after inhaled oxygen ≥6.5 Wood units (estimated pulmonary vascular resistance ≥5 Wood units; OR, 12.23 95% CI, 2.12-70.46;
<0.01), and artery oxygen saturation at rest <95% (OR, 3.34 95% CI, 1.07-10.44;
=0.04). We established the prediction model with the C-statistics of 0.85 (95% CI, 0.77-0.93;
<0.01), and the C-statistic was 0.83 (95% CI, 0.80-0.86) after bootstrapping 10 000 times with a good performance of the nomogram calibration curve for predicting persistent PH.
Our study presents a multivariable risk stratification model for persistent PH after shunt correction in adults with pretricuspid shunts. This model, based on 3 hemodynamic predictors after inhaled oxygen, may assist in identifying individuals at higher risk of persistent PH after shunt correction.
In this study, light microscope, scanning and transmission electron microscope, hematoxylin-eosin and fluorescent staining, and mass spectrometry methods were employed to observe the calcium ...carbonate (CaCO3) crystal formation, hemocyte release and transportation, and hemocyte distribution at the shell regeneration area and to analyse the proteome of hemocytes in the pearl oyster, Pinctada fucata. The results indicated that intracellular CaCO3 crystals were observed in circulating hemocytes in P. fucata, implying that there was a suitable microenvironment for crystal formation in the hemocytes. This conclusion was further supported by the proteome analysis, in which various biomineralization-related proteins were detected. The crystal-bearing hemocytes, mainly granulocytes, may be released to extrapallial fluid (EPF) by the secretory cavities distributed on the outer surface of the mantle centre. These granulocytes in the EPF and between the regenerated shells were abundant and free. In the regenerated prismatic layer, the granulocytes were fused into each column and fragmented with the duration of shell maturation, suggesting the direct involvement of hemocytes in shell regeneration. Overall, this study provided evidence that hemocytes participated in CaCO3 crystal formation, transportation and shell regeneration in the pearl oyster. These results are helpful to further understand the exact mechanism of hemocyte-mediated biomineralization in shelled molluscs.
•CaCO3 crystals are observed in circulating hemocytes in Pinctada fucata.•Hemocyte proteome shows the molecular basis for CaCO3 crystal formation.•Crystal-bearing hemocytes may be secreted by secretory cavities on mantle.•Hemocytes directly involve in the regeneration of prismatic layer in P. fucata.
Biological response to rapid changing environments is an outstanding research question in ecology and evolution. Biological invasions provide excellent "natural" experiments to study such a complex ...response process, as invaders often encounter rapidly changing environments during biological invasions. The regulation of heat shock proteins (Hsp) is a common pathway responsible for various environmental stresses; however, the comprehensive study on Hsp system across the whole genome and potential roles in determining invasion success are still largely unexplored. Here, we used a marine invasive model ascidian,
, to investigate transcriptional response of Hsp-related genes to harsh environments. We identified 32 genes, including three Hsp20, six Hsp40, ten Hsp60, eight Hsp70, three Hsp90, one Hsp100, and one heat shock transcription factor (Hsf), across the whole genome of
. We further characterized gene structure and protein motifs, and identified potential heat shock elements (HSEs) in promoters of Hsp genes. The expression analysis showed that most Hsp genes, but not all, were involved in transcriptional response to temperature and salinity challenges in a duration- and stress-specific pattern, and the maximum amplitude of induction occurred in Hsp70-4 after 1-h of high temperature treatment. However, the Hsf gene was scarcely induced and limited interactions were predicted between Hsp and Hsf genes. Our study provide the first systematic genome-wide analysis of Hsp and Hsf family in the marine invasive model ascidian, and our results are expected to dissect Hsp-based molecular mechanisms responsible for extreme environmental adaptation using
as a model system.
Ocean acidification and global warming have been shown to significantly affect the physiological performances of marine calcifiers; however, the underlying mechanisms remain poorly understood. In ...this study, the transcriptome and biomineralization responses of Pinctada fucata to elevated CO2 (pH 7.8 and pH 7.5) and temperature (25 °C and 31 °C) are investigated. Increases in CO2 and temperature induced significant changes in gene expression, alkaline phosphatase activity, net calcification rates and relative calcium content, whereas no changes are observed in the shell ultrastructure. "Ion and acid-base regulation" related genes and "amino acid metabolism" pathway respond to the elevated CO2 (pH 7.8), suggesting that P. fucata implements a compensatory acid-base mechanism to mitigate the effects of low pH. Additionally, "anti-oxidation"-related genes and "Toll-like receptor signaling", "arachidonic acid metabolism", "lysosome" and "other glycan degradation" pathways exhibited responses to elevated temperature (25 °C and 31 °C), suggesting that P. fucata utilizes anti-oxidative and lysosome strategies to alleviate the effects of temperature stress. These responses are energy-consuming processes, which can lead to a decrease in biomineralization capacity. This study therefore is important for understanding the mechanisms by which pearl oysters respond to changing environments and predicting the effects of global climate change on pearl aquaculture.
The world's largest water diversion, the South-to-North Water Transfer Project (SNWTP) in China, has created an "invasion highway" to introduce invasive golden mussels (
) from the Yangtze River ...basin to Beijing. To examine the spread and colonization patterns of this newly introduced invasive species, we conducted comprehensive environmental DNA (eDNA)-based early detection and conventional field surveys across all water bodies in five river basins in Beijing from 2020 to 2023. Our results indicated a rapid spread over the past four years. Among the 130 tested sites, the number of sites with positive signals from eDNA analysis exhibited an annual increase: Commencing with four infested sites identified through field surveys in 2019, eDNA analysis detected an additional 13, 11, and 10 positive sites in 2020, 2021, and 2022, respectively, and a substantial rise comprising an additional 28 sites in 2023. Conventional field surveys detected mussels 1-3 years later than eDNA-based analysis at 16 sites. Across all 16 sites, we detected a low population density ranging from 1 to 30 individuals/m
. These findings collectively indicate that the invasions by golden mussels in Beijing are still in their early stages. To date, golden mussels have successfully colonized four out of the five investigated river basins, including the Jiyun River (22.2% positive sites), North Canal River (59.6% positive sites), Chaobai River (40% positive sites), and Yongding River (63.6% positive sites), with the North Canal River and Yongding River being the most heavily infested. Currently, only the Daqing River basin remains uninfested. Given the significant number of infested sites and the ongoing transport of large new propagules via SNWTP, further rapid spread and colonization are anticipated across aquatic ecosystems in Beijing and beyond. Consequently, we call for the proper implementation of effective management strategies, encompassing early detection, risk assessment, and the use of appropriate control measures to mitigate the potential ecological and economic damages in invaded ecosystems.
Biofouling mediated by byssus adhesion in invasive bivalves has become a global environmental problem in aquatic ecosystems, resulting in negative ecological and economic consequences. Previous ...studies suggested that mechanisms responsible for byssus adhesion largely vary among bivalves, but it is poorly understood in freshwater species. Understanding of byssus structure and protein composition is the prerequisite for revealing these mechanisms. Here, we used multiple methods, including scanning electron microscope, liquid chromatography-tandem mass spectrometry, transcriptome sequencing, real-time quantitative PCR, inductively coupled plasma mass spectrometry, to investigate structure, and protein composition of byssus in the highly invasive freshwater mussel
. The results indicated that the structure characteristics of adhesive plaque, proximal and distal threads were conducive to byssus adhesion, contributing to the high biofouling capacity of this species. The 3,4-dihydroxyphenyl-α-alanine (Dopa) is a major post-transnationally modification in
byssus. We identified 16 representative foot proteins with typical repetitive motifs and conserved domains by integrating transcriptomic and proteomic approaches. In these proteins, Lfbp-1, Lffp-2, and Lfbp-3 were specially located in foot tissue and highly expressed in the rapid byssus formation period, suggesting the involvement of these foot proteins in byssus production and adhesion. Multiple metal irons, including Ca
, Mg
, Zn
, Al
, and Fe
, were abundant in both foot tissue and byssal thread. The heavy metals in these irons may be directly accumulated by
from surrounding environments. Nevertheless, some metal ions (e.g., Ca
) corresponded well with amino acid preferences of
foot proteins, suggesting functional roles of these metal ions by interacting with foot proteins in byssus adhesion. Overall, this study provides structural and molecular bases of adhesive mechanisms of byssus in
, and findings here are expected to develop strategies against biofouling by freshwater organisms.
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