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1.
Harmful Algae ; 138: 102695, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39244231

RESUMO

In recent years, red tides have increased worldwide in frequency, intensity, involving a higher number of causative species during the events. As the most commonly used method for control of red tides, modified clay (MC) was found to have differential ability to remove various red tide species. However, the underlying mechanisms have not yet been completely elucidated. In this study, the use of MC to remove three typical disaster-causing species, Aureococcus anophagefferens, Prorocentrum donghaiense and Heterosigma akashiwo, was investigated, and differential removal of these species was probed with insights into their biocellular properties and mechanical interactions. The results showed that removal efficiencies of the three species by MC decreased in the order P. donghaiense > A. anophagefferens > H. akashiwo, while the sedimentation rates decreased in the order H. akashiwo > P. donghaiense > A. anophagefferens. Analyses of the cell surface properties and redundancy analysis (RDA) revealed that the highest surface zeta potential of -5.32±0.39 mV made P. donghaiense the most easily removed species; the smallest cell size of 3.30±0.03 µm facilitated the removal of A. anophagefferens; and the highest hydrophobicity with a H2O surface contact angle of 98.50±4.31° made the removal of H. akashiwo difficult. X-ray photoelectron spectroscopy (XPS) data indicated that the electronegativity of P. donghaiense was caused by carboxyl groups and phosphodiester groups, and the hydrophobicity of H. akashiwo was associated with a high C-(C, H) content on the cell surface. According to the extended Derjaguin, Landau, Verwey, and Overbeek (ex-DLVO) theory calculation, differences in the interaction energies between MC and the three red tide species effectively explained their different sedimentation rates. In addition, the degree of oxidative damage caused by MC to the three red tide species differed, which also affected the removal of red tide organisms.


Assuntos
Argila , Proliferação Nociva de Algas , Argila/química , Silicatos de Alumínio/química
2.
Sci Rep ; 14(1): 20368, 2024 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-39223206

RESUMO

Local inflammatory microenvironment in the early stage of myocardial infarction (MI) severely impaired cardiac recovery post-MI. Macrophages play a pivotal role in this process. A classical glycolytic inhibitor, 2-Deoxy-Glucose (2-DG), has been found to regulate the excessive pro-inflammatory macrophage polarization in the infarcted myocardium. This study investigated the effect of 2-DG-loaded chitosan/gelatin composite patch on the infarct microenvironment post-MI and its impact on cardiac repair. The results showed that the 2-DG patch significantly inhibited the expression of inflammatory cytokines, alleviated reactive oxygen species (ROS) accumulation, repressed the proinflammatory polarization of macrophages, attenuated local inflammatory microenvironment in the ischemic hearts, as well as improved cardiac function, reduced scar size, and promoted angiogenesis post-MI. In terms of mechanism, 2-DG exerts anti-inflammatory effects through inhibiting the NF-κB signaling pathway and reducing the assembly and activation of the NLRP3 inflammasome. These findings suggest that 2-DG composite patch may represent a promising therapeutic strategy for cardiac repair after MI.


Assuntos
Desoxiglucose , Infarto do Miocárdio , Proteína 3 que Contém Domínio de Pirina da Família NLR , Animais , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/metabolismo , Desoxiglucose/farmacologia , Desoxiglucose/administração & dosagem , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , NF-kappa B/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Camundongos , Masculino , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Transdução de Sinais/efeitos dos fármacos , Quitosana/farmacologia , Quitosana/química , Gelatina/química , Citocinas/metabolismo , Miocárdio/metabolismo , Miocárdio/patologia , Modelos Animais de Doenças , Inflamassomos/metabolismo , Inflamassomos/efeitos dos fármacos , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/administração & dosagem , Camundongos Endogâmicos C57BL
3.
Adv Mater ; : e2407437, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39300864

RESUMO

There has been a significant focus on real topological systems that enjoy space-time inversion symmetry and lack spin-orbit coupling. While the theoretical classification of the real topology has been established, more progress has yet to be made in the materials realization of real topological phononic states in 3D. To address this crucial issue, high-throughput computing is performed to inspect the real topology in the phonon spectrums of the 3D carbon allotropes. Among 1661 carbon allotropes listed in the Samara Carbon Allotrope Database (SACADA), 79 candidates host a phononic real Chern insulating (PRCI) state, 2 candidates host a phononic real nodal line (PRNL) state, 12 candidates host a phononic real Dirac point (PRDP) state, and 10 candidates host a phononic real triple-point pair (PRTPP) state. The PRCI, PRNL, PRTPP, and PRDP states of 27-SG. 166-pcu-h, 1081-SG. 194-42T13-CA, 52-SG. 141-gis, and 132-SG. 191-3,4T157 are exhibited as illustrative examples, and the second-order phononic hinge modes are explored. This study broadens the understanding of 3D topological phonons and expands the material candidates with phononic hinge modes and phononic real topology.

4.
Nano Lett ; 24(33): 10402-10407, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39115228

RESUMO

The helical edge states (ESs) protected by underlying Z2 topology in two-dimensional topological insulators (TIs) arouse upsurges in saturable absorptions thanks to the strong photon-electron coupling in ESs. However, limited TIs demonstrate clear signatures of topological ESs at liquid nitrogen temperatures, hindering the applications of such exotic quantum states. Here, we demonstrate the existence of one-dimensional (1D) ESs at the step edge of the quasi-1D material Ta2NiSe7 at 78 K by scanning tunneling microscopy. Such ESs are rather robust against the irregularity of the edges, suggesting a possible topological origin. The exfoliated Ta2NiSe7 flakes were used as saturable absorbers (SAs) in an Er-doped fiber laser, hosting a mode-locked pulse with a modulation depth of up to 52.6% and a short pulse duration of 225 fs, far outstripping existing TI-based SAs. This work demonstrates the existence of robust 1D ESs and the superior SA performance of Ta2NiSe7.

5.
Front Immunol ; 15: 1428551, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39086479

RESUMO

Background: Myocardial inflammation and apoptosis induced by cirrhosis are among the primary mechanisms of cirrhotic cardiomyopathy. CD73, a common extracellular nucleotidase also known as 5'-nucleotidase, is associated with the progression of inflammation and immunity in multiple organs. However, the mechanism by which CD73 contributes to myocardial inflammation and apoptosis in cirrhosis remains unclear. Methods: In this study, a cirrhotic cardiomyopathy model in mice was established by bile duct ligation. Myocardial-specific overexpression of CD73 was achieved by tail vein injection of AAV9 (adeno-associated virus)-cTNT-NT5E-mCherry, and cardiac function in mice was assessed using echocardiography. Myocardial inflammation infiltration and apoptosis were evaluated through pathological observation and ELISA assays. The expression of CD73, A2AR, apoptotic markers, and proteins related to the NF-κB pathway in myocardial tissue were measured. Results: In the myocardial tissue of the cirrhotic cardiomyopathy mouse model, the expression of CD73 and A2AR increased. Overexpression of CD73 in the myocardium via AAV9 injection and stimulation of A2AR with CGS 21680 inhibited myocardial inflammation and cardiomyocyte apoptosis induced by cirrhosis. Additionally, overexpression of CD73 suppressed the activation of the NF-κB pathway by upregulating the expression of the adenosine receptor A2A. Conclusion: Our study reveals that the CD73/A2AR signaling axis mitigates myocardial inflammation and apoptosis induced by cirrhosis through negative feedback regulation of the NF-κB pathway.


Assuntos
5'-Nucleotidase , Cardiomiopatias , Cirrose Hepática , Receptor A2A de Adenosina , Transdução de Sinais , Animais , Masculino , Camundongos , 5'-Nucleotidase/metabolismo , Apoptose , Cardiomiopatias/metabolismo , Cardiomiopatias/etiologia , Cardiomiopatias/imunologia , Modelos Animais de Doenças , Retroalimentação Fisiológica , Proteínas Ligadas por GPI , Cirrose Hepática/imunologia , Cirrose Hepática/metabolismo , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Receptor A2A de Adenosina/metabolismo
6.
Phys Rev Lett ; 133(5): 056401, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39159119

RESUMO

Spintronics, a technology harnessing electron spin for information transmission, offers a promising avenue to surpass the limitations of conventional electronic devices. While the spin directly interacts with the magnetic field, its control through the electric field is generally more practical, and has become a focal point in the field. Here, we propose a mechanism to realize static and almost uniform effective magnetic field by gate-electric field. Our method employs two-dimensional altermagnets with valley-mediated spin-layer coupling (SLC), in which electronic states display valley-contrasted spin and layer polarization. For the low-energy valley electrons, a uniform gate field is approximately identical to a uniform magnetic field, leading to predictable control of spin. Through symmetry analysis and ab initio calculations, we predict altermagnetic monolayer Ca(CoN)_{2} and its family materials as potential candidates hosting SLC. We show that an almost uniform magnetic field (B_{z}) indeed is generated by gate field (E_{z}) in Ca(CoN)_{2} with B_{z}∝E_{z} in a wide range, and B_{z} reaches as high as about 10^{3} T when E_{z}=0.2 eV/Å. Furthermore, owing to the clean band structure and SLC, one can achieve perfect and switchable spin and valley currents and significant tunneling magnetoresistance in Ca(CoN)_{2} solely using the gate field. Our work provides new opportunities to generate predictable control of spin and design spintronic devices that can be controlled by purely electric means.

7.
iScience ; 27(8): 110575, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39193189

RESUMO

The phytoplankton Phaeocystis globosa plays an important role in sulfur cycling and climate control, and can develop harmful algal blooms (HABs). Here we report a chromosome-scale reference genome assembly of P. globosa, which enable in-depth analysis of molecular underpinnings of important ecological characteristics. Comparative genomic analyses detected two-rounds of genome duplications that may have fueled evolutionary innovations. The genome duplication may have resulted in the formation of dual HiDP and LoDP dimethylsulphoniopropionate (DMSP) biosynthesis pathways in P. globosa. Selective gene family expansions may have strengthened biological pathways critical for colonial formation that is often associated with the development of algal blooms. The copy numbers of rhodopsin genes are variable in different strains, suggesting that rhodopsin genes may play a role in strain-specific adaptation to ecological factors. The successful reconstruction of the P. globosa genome sets up an excellent platform that facilitates in-depth research on bloom development and DMSP metabolism.

8.
Mar Pollut Bull ; 206: 116700, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39002214

RESUMO

Phycosphere bacteria can regulate the dynamics of different algal blooms that impact marine ecosystems. Phaeocystis globosa can alternate between solitary free-living cells and colonies and the latter morphotype is dominate during blooms. The mechanisms underlying the formation of these blooms have received much attention. High throughput sequencing results showed that the bacterial community composition differed significantly between colony and solitary strains in bacterial composition and function. It was found that the genera SM1A02 and Haliea were detected only among the colony strains and contribute to ammonium accumulation in colonies, and the genus Sulfitobacter was abundant among the colony strains that were excellent at producing DMS. In addition, the bacterial communities of the two colony strains exhibited stronger abilities for carbon and sulfur metabolism, energy metabolism, vitamin B synthesis, and signal transduction, providing inorganic and organic nutrients and facilitating tight communication with the host algae, thereby promoting growth and bloom development.


Assuntos
Bactérias , Eutrofização , Haptófitas , Haptófitas/crescimento & desenvolvimento , Ecossistema
9.
Chemosphere ; 362: 142668, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38906188

RESUMO

Harmful algal blooms (HABs), especially those caused by toxic dinoflagellates, are spreading in marine ecosystems worldwide. Notably, the prevalence of Karenia brevis blooms and potent brevetoxins (BTXs) pose a serious risk to public health and marine ecosystems. Therefore, developing an environmentally friendly method to effectively control HABs and associated BTXs has been the focus of increasing attention. As a promising method, modified clay (MC) application could effectively control HABs. However, the environmental fate of BTXs during MC treatment has not been fully investigated. For the first time, this study revealed the effect and mechanism of BTX removal by MC from the perspective of adsorption and transformation. The results indicated that polyaluminium chloride-modified clay (PAC-MC, a typical kind of MC) performed well in the adsorption of BTX2 due to the elevated surface potential and more binding sites. The adsorption process was a spontaneous endothermic process that conformed to pseudo-second-order adsorption kinetics (k2 = 6.8 × 10-4, PAC-MC = 0.20 g L-1) and the Freundlich isotherm (Kf = 55.30, 20 °C). In addition, detailed product analysis using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) indicated that PAC-MC treatment effectively removed the BTX2 and BTX3, especially those in the particulate forms. Surprisingly, PAC-MC could promote the transformation of BTX2 to derivatives, including OR-BTX2, OR-BTX3, and OR-BTX-B5, which were proven to have lower cytotoxicity.


Assuntos
Argila , Dinoflagellida , Proliferação Nociva de Algas , Toxinas Marinhas , Adsorção , Argila/química , Dinoflagellida/crescimento & desenvolvimento , Oxocinas/química , Cinética , Poluentes Químicos da Água/química , Toxinas de Poliéter
10.
Mar Pollut Bull ; 205: 116617, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38917494

RESUMO

Excessive nitrate input is one of the primary factors causing nearshore eutrophication. This study applied the nitrate stable isotope techniques to analyse the biogeochemical processes and sources of nitrate in the Bohai Sea (BHS). The results showed that intensive NO3- assimilation probably occurred at surface in summer, while nitrification primarily occurred in the Yellow River diluted water. In autumn, regional assimilation and nitrification were still identified. For avoiding the interference from assimilation, the isotopic fractionations were further calculated as correction data for the quantitative analysis of nitrate sources. The river inputs were identified as the primary source of nitrate in the BHS in summer and autumn, accounting for >50 %, and the atmospheric deposition was the secondary source. This study provides quantitative data for evaluating the significance of river inputs to the nearshore nitrate, which will be beneficial to policy formulation on the BHS eutrophication control.


Assuntos
Monitoramento Ambiental , Modelos Teóricos , Nitratos , Poluentes Químicos da Água , Nitratos/análise , China , Oceanos e Mares , Água do Mar/química , Ciclo do Nitrogênio , Nitrificação , Poluentes Químicos da Água/análise , Poluição Química da Água/estatística & dados numéricos
11.
Mar Pollut Bull ; 203: 116437, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38733893

RESUMO

Dissolved algal organic matter (dAOM) originating from harmful algal blooms (HABs) can deteriorate the quality of municipal water supplies, threaten the health of aquatic environments, and interfere with modified clay (MC)-based HABs control measures. In this study, we explored the composition of dAOM from Prorocentrum donghaiense, a typical HAB organism, and assessed the influence of dAOM on MC flocculation. Our results suggested that dAOM composition was complex and had a wide molecular weight (MW) distribution. MW and electrical properties were important dAOM characteristics affecting flocculation and algal removal efficiency of MC. Negatively charged high-MW components (>50 kDa) critically affected algal removal efficiency, reducing the zeta potential of MC particles and leading to small and weak flocs. However, the effect of dAOM depended on its concentration. When the cell density of P. donghaiense reached HAB levels, the high-MW dAOM strongly decreased the algal removal efficiency of MC.


Assuntos
Argila , Floculação , Proliferação Nociva de Algas , Argila/química
12.
Harmful Algae ; 134: 102629, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38705615

RESUMO

Electrophysiological techniques, by measuring bioelectrical signals and ion channel activities in tissues and cells, are now widely utilized to study ion channel-related physiological functions and their underlying mechanisms. Electrophysiological techniques have been extensively employed in the investigation of animals, plants, and microorganisms; however, their application in marine algae lags behind that in other organisms. In this paper, we present an overview of current electrophysiological techniques applicable to algae while reviewing the historical usage of such techniques in this field. Furthermore, we explore the potential specific applications of electrophysiological technology in harmful algal bloom (HAB) research. The application prospects in the studies of stress tolerance, competitive advantage, nutrient absorption, toxin synthesis and secretion by HAB microalgae are discussed and anticipated herein with the aim of providing novel perspectives on HAB investigations.


Assuntos
Proliferação Nociva de Algas , Microalgas , Microalgas/fisiologia , Proliferação Nociva de Algas/fisiologia , Fenômenos Eletrofisiológicos
13.
Plants (Basel) ; 13(9)2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38732418

RESUMO

Soybean is considered one of the most drought-sensitive crops, and ROS homeostasis can regulate drought tolerance in these plants. Understanding the mechanism of H2O2 homeostasis and its regulatory effect on drought stress is important for improving drought tolerance in soybean. We used different concentrations of polyethylene glycol (PEG) solutions to simulate the progression from weak drought stress (0.2%, 0.5%, and 1% PEG) to strong drought stress (5% PEG). We investigated the responses of the soybean plant phenotype, ROS level, injury severity, antioxidant system, etc., to different weak drought stresses and subsequent strong drought stresses. The results show that drought-treated plants accumulated H2O2 for signaling and exhibited drought tolerance under the following stronger drought stress, among which the 0.5% PEG treatment had the greatest effect. Under the optimal treatment, there was qualitatively describable H2O2 homeostasis, characterized by a consistent increasing amplitude in H2O2 content compared with CK. The H2O2 signal formed under the optimum treatment induced the capacity of the antioxidant system to remove excess H2O2 to form a primary H2O2 homeostasis. The primary H2O2 homeostasis further induced senior H2O2 homeostasis under the following strong drought and maximized the improvement of drought tolerance. These findings might suggest that gradual drought training could result in stepwise H2O2 homeostasis to continuously improve drought tolerance.

14.
Adv Mater ; 36(29): e2402232, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38684179

RESUMO

Recently, the real topology has been attracting widespread interest in two dimensions (2D). Here, based on first-principles calculations and theoretical analysis, the monolayer Cr2Se2O (ML-CrSeO) is revealed as the first material example of a 2D antiferromagnetic (AFM) real Chern insulator (RCI) with topologically protected corner states. Unlike previous RCIs, it is found that the real topology of the ML-CrSeO is rooted in one certain mirror subsystem of the two spin channels, and cannot be directly obtained from all the valence bands in each spin channel as commonly believed. In particular, due to antiferromagnetism, the corner modes in ML-CrSeO exhibit strong corner-contrasted spin polarization, leading to spin-corner coupling (SCC). This SCC enables a direct connection between spin space and real space. Consequently, large and switchable net magnetization can be induced in the ML-CrSeO nanodisk by electrostatic means, such as potential step and in-plane electric field, and the corresponding magnetoelectric responses behave like a sign function, distinguished from that of the conventional multiferroic materials. This work considerably broadens the candidate range of RCI materials, and opens up a new direction for topo-spintronics and 2D AFM materials research.

15.
Plants (Basel) ; 13(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38475589

RESUMO

RNAs play important roles in regulating biological growth and development. Advancements in RNA-imaging techniques are expanding our understanding of their function. Several common RNA-labeling methods in plants have pros and cons. Simultaneously, plants' spontaneously fluorescent substances interfere with the effectiveness of RNA bioimaging. New technologies need to be introduced into plant RNA luminescence. Aggregation-induced emission luminogens (AIEgens), due to their luminescent properties, tunable molecular size, high fluorescence intensity, good photostability, and low cell toxicity, have been widely applied in the animal and medical fields. The application of this technology in plants is still at an early stage. The development of AIEgens provides more options for RNA labeling. Click chemistry provides ideas for modifying AIEgens into RNA molecules. The CRISPR/Cas13a-mediated targeting system provides a guarantee of precise RNA modification. The liquid-liquid phase separation in plant cells creates conditions for the enrichment and luminescence of AIEgens. The only thing that needs to be looked for is a specific enzyme that uses AIEgens as a substrate and modifies AIEgens onto target RNA via a click chemical reaction. With the development and progress of artificial intelligence and synthetic biology, it may soon be possible to artificially synthesize or discover such an enzyme.

16.
Diabetes Metab J ; 48(4): 716-729, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38408883

RESUMO

BACKGRUOUND: Diabetes-induced cardiac fibrosis is one of the main mechanisms of diabetic cardiomyopathy. As a common histone methyltransferase, enhancer of zeste homolog 2 (EZH2) has been implicated in fibrosis progression in multiple organs. However, the mechanism of EZH2 in diabetic myocardial fibrosis has not been clarified. METHODS: In the current study, rat and mouse diabetic model were established, the left ventricular function of rat and mouse were evaluated by echocardiography and the fibrosis of rat ventricle was evaluated by Masson staining. Primary rat ventricular fibroblasts were cultured and stimulated with high glucose (HG) in vitro. The expression of histone H3 lysine 27 (H3K27) trimethylation, EZH2, and myocardial fibrosis proteins were assayed. RESULTS: In STZ-induced diabetic ventricular tissues and HG-induced primary ventricular fibroblasts in vitro, H3K27 trimethylation was increased and the phosphorylation of EZH2 was reduced. Inhibition of EZH2 with GSK126 suppressed the activation, differentiation, and migration of cardiac fibroblasts as well as the overexpression of the fibrotic proteins induced by HG. Mechanical study demonstrated that HG reduced phosphorylation of EZH2 on Thr311 by inactivating AMP-activated protein kinase (AMPK), which transcriptionally inhibited peroxisome proliferator-activated receptor γ (PPAR-γ) expression to promote the fibroblasts activation and differentiation. CONCLUSION: Our data revealed an AMPK/EZH2/PPAR-γ signal pathway is involved in HG-induced cardiac fibrosis.


Assuntos
Proteínas Quinases Ativadas por AMP , Diabetes Mellitus Experimental , Cardiomiopatias Diabéticas , Proteína Potenciadora do Homólogo 2 de Zeste , Fibrose , Miocárdio , PPAR gama , Transdução de Sinais , Animais , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , PPAR gama/metabolismo , Camundongos , Ratos , Cardiomiopatias Diabéticas/metabolismo , Cardiomiopatias Diabéticas/etiologia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/complicações , Masculino , Proteínas Quinases Ativadas por AMP/metabolismo , Miocárdio/patologia , Miocárdio/metabolismo , Ratos Sprague-Dawley , Fibroblastos/metabolismo , Camundongos Endogâmicos C57BL , Células Cultivadas , Fosforilação
17.
Sci Total Environ ; 919: 170652, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38331282

RESUMO

The prevalence of harmful algal blooms (HABs), especially in mariculture waters, has become a concern for environmental and human health worldwide. Notably, the frequent occurrence of HABs relies upon a substantial supply of available nutrients, which are influenced by nutrient recycling. However, nutrient regeneration, transformation pattern, and their contribution to HABs in mariculture waters remain largely unknown. In this study, by combining field investigation and incubation experiments from June to September 2020, the temporal variations in nutrients and algal composition were revealed. In addition, the nutrient regeneration and assimilation rates in the water column during two continuous algal blooms were measured. The results indicated that organic nutrients, which were the dominant components, strongly stimulated nutrient regeneration. High regeneration rates were observed, with dissolved inorganic nitrogen (DIN) and phosphorous (DIP) regeneration rates ranging from 0.25 to 2.64 µmol/L·h and 0.01 to 0.09 µmol/L·h, respectively. Compared to the direct uptake of organic nutrients, the rapid regeneration of inorganic nutrients played a vital role in sustaining continuous algal blooms, as regenerated DIN contributed 100 % while regenerated DIP contributed 72-100 % of the algal assimilation demand. Furthermore, the redundancy analysis and inverse solution equations indicated that different N transformation patterns and utilization strategies occurred during Heterosigma and Nannochloris blooms. The shorter N recycling pathway and faster NH4+ supply rates provided favorable conditions for the dominance of Nannochloris over Heterosigma, which had a preference for the uptake of NO3-. In conclusion, we propose that nutrient regeneration is a key maintenance mechanism underlying the maintenance of continuous algal blooms, and different N transformation patterns and utilization strategies regulate algal communities in mariculture waters.


Assuntos
Proliferação Nociva de Algas , Água , Humanos , Nutrientes/análise , Nitrogênio/análise , Fósforo/análise
18.
PLoS One ; 18(11): e0288818, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37967130

RESUMO

In the natural environment, complex and changeable meteorological factors can influence changes in the internal physiology and phenotype of crops. It is important to learn how to convert complex meteorological factor stimuli into plant perception phenotypes when analyzing the biological data obtained under the natural field condition. We restored the true gradation distribution of leaf color, which is also known as the skewed distribution of color scale, and obtained 20 multi-dimensional color gradation skewness-distribution (CGSD) parameters based on the leaf color skewness parameter system. Furthermore, we analyzed the correlation between the five corresponding meteorological factors and canopy CGSD parameters of peppers growing in a greenhouse and cabbages growing in an open air environment, built response model and inversion mode of leaf color to meteorological factors. Based on the analysis, we find a new method for correlating complex environmental problems with multi-dimensional parameters. This study provides a new idea for building a correlation model that uses leaf color as a bridge between meteorological factors and plants internal physiological state.


Assuntos
Meio Ambiente , Folhas de Planta , Fenótipo , Conceitos Meteorológicos , Produtos Agrícolas , Cor
19.
Harmful Algae ; 129: 102516, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37951610

RESUMO

Paralytic shellfish toxins (PSTs) are widely distributed globally and are produced by Alexandrium pacificum in marine system. However, the characteristics of toxins producing and secreting associated with growth phases are still unclear, especially whether A. pacificum has the ability to actively secrete PSTs is controversial. In this study, variation characteristics of intracellular and extracellular PSTs contents associated with A. pacificum growth phases were investigated thoroughly. The results showed that intracellular and extracellular PSTs contents increased sharply during the exponential phase. But during the stationary phase, the intracellular PSTs content increased by only 26 %, and the extracellular PSTs content did not increase significantly. Since the increase in extracellular PSTs content mainly occurred at the exponential phase, when most cells were living, we speculated that active PSTs secretion of living cells might be an important production pathway of extracellular toxins besides leakage from dead cells. Furthermore, toxin cell quota variation associated with the growth phase was analysed. In the exponential phase, the toxin cell quota first increased and then decreased, with a maximum of 19.02 ± 1.80 fmol/cell at 6 d. However, after entering the stationary phase, this value slowly increased again, suggesting that vigilance should be raised for the plateau of Alexandrium blooms. In addition, cells in the exponential phase mainly produced O-sulfated components such as GTX1&4, cells in the stationary phase mainly produced O-sulfate-free components such as GTX5. In this study, the toxigenic rules of A. pacificum were comprehensively uncovered, which provided theoretical guidance for the prevention and mitigation of A. pacificum blooms.


Assuntos
Dinoflagellida , Toxinas Biológicas
20.
Harmful Algae ; 129: 102499, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37951615

RESUMO

The impacts of harmful algal blooms (HABs) on economies, public health, ecosystems, and aquaculture across the globe have all increased in recent decades, and this has been acutely the case in China. Here, we review the history of HABs and HABs research in China, as well as recent trends in HABs and future prospects of HAB science in China. The most updated analyses demonstrated that the number of HAB events, the number of HAB species, the aerial coverage of HABs, and the impacts of HABs in Chinese waters during the 21st century were all higher than that during the last two decades of the 20th century. The increase in the number of HABs in China has been significantly correlated with the increased discharge of ammonium and total phosphorus into coastal waters (p < 0.01 for both). Notable newly recognized events this century have included chronic HABs caused by Prorocentrum donghaiense and Karenia mikimotoi, a paralytic shellfish poisoning event caused by Gymnodinium catenatum that sickened 80 people, brown tides caused by Aureococcus anophagefferens, green tides caused by Ulva prolifera, golden tides caused by Sargassum horneri, and the disruption of a nuclear power plant caused by a bloom of Phaeocystis globosa. A series of key discoveries regarding HABs has been made this century including documentation of nearly all known HAB toxins in Chinese waters, discovery of novel cyst-formation and/or life stages of multiple HABs-causing species, identification of the chemical and physical oceanographic drivers of multiple HABs including those formed by P. donghaiense, K. mikimotoi, and U. prolifera, and the successful mitigation of HABs via the use of modified clay approaches. Future research prospects highlighted include the use of macroalgae as a means to prevent, mitigate, and control (PCM) HABs and the process by which multi-disciplinary studies involving molecular approaches (omics), remote in situ detection, artificial intelligence, and mega-data analyses might be used to develop refined and realistic HAB forecasting platforms. Collectively, this review demonstrates the significant evolution of HAB science since the 20th century in China and demonstrates that while HABs in China are complex and widespread, recent and on-going discoveries make the development of detailed understanding and effective measures to mitigate the negative effects of HABs a hopeful outcome in the coming years.


Assuntos
Dinoflagellida , Proliferação Nociva de Algas , Humanos , Ecossistema , Inteligência Artificial , China
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