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1.
Integr Cancer Ther ; 23: 15347354241236205, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38462929

RESUMEN

BACKGROUND: Siwu Decoction (SWD) is a well-known classical TCM formula that has been shown to be effective as a basis for preventing and reducing liver metastases (LM). However, the active ingredients and potential molecular mechanisms remain unclear. OBJECTIVE: This study aimed to systematically analyze the active ingredients and potential molecular mechanisms of SWD on LM and validate mechanisms involved. MATERIALS AND METHODS: The active ingredients in SWD were extracted by UHPLC-MS/MS in a latest study. Protox II was retrieved to obtain toxicological parameters to detect safety. Swiss Target Prediction database was exploited to harvest SWD targets. Five databases, Gene Cards, DisGeNET, Drugbank, OMIM, and TTD, were employed to filter pathogenic targets of LM. STRING database was utilized to construct the protein-protein interaction network for therapeutic targets, followed by Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. GEPIA database and the Human Protein Atlas were taken to observe the expression of core genes and proteins. ImmuCellAI algorithm was applied to analyze the immune microenvironment and survival relevant to core genes. Molecular docking was performed to verify the affinity of SWD effective ingredients to core targets. In vivo experiments were carried out to validate the anti-LM efficacy of SWD and verify the pivotal mechanisms of action. RESULTS: Eighteen main bioactive phytochemicals identified were all non-hepatotoxic. PPI network acquired 118 therapeutic targets, of which VEGFA, CASP3, STAT3, etc. were identified as core targets. KEGG analysis revealed that HIF-1 pathway and others were critical. After tandem targets and pathways, HIF-1/VEGF was regarded as the greatest potential pathway. VEGFA and HIF-1 were expressed differently in various stages of cancer and normal tissues. There was a negative regulation of immunoreactive cells by VEGFA, which was influential for prognosis. Molecular docking confirmed the tight binding to VEGFA. This study revealed the exact effect of SWD against LM, and identified significant inhibition the expression of HIF-1α, VEGF, and CD31 in the liver microenvironment. CONCLUSION: This study clarified the active ingredients of SWD, the therapeutic targets of LM and potential molecular mechanisms. SWD may protect against LM through suppressing HIF-1/VEGF pathway.


Asunto(s)
Medicamentos Herbarios Chinos , Neoplasias Hepáticas , Humanos , Simulación del Acoplamiento Molecular , Farmacología en Red , Espectrometría de Masas en Tándem , Factor A de Crecimiento Endotelial Vascular , Neoplasias Hepáticas/tratamiento farmacológico , Medicamentos Herbarios Chinos/farmacología , Microambiente Tumoral
2.
Biochim Biophys Acta Rev Cancer ; 1879(2): 189081, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38280471

RESUMEN

Distant metastasis is responsible for high mortality in most cancer cases and the lung is one of the most common target organs, severely affecting the quality of daily life and overall survival of cancer patients. With relevant research breakthroughs accumulating, scientists have developed a deeper understanding of lung metastasis (LM) from the rudimentary "seed and soil" theory to a more vivid concept of the pre-metastatic niche (PMN). Thus, the mechanisms of PMN formation become considerably complicated, involving various types of cells, chemokines, cytokines, and proteins, providing potential biomarkers for improved LM diagnosis and treatment techniques. Here we summarized the latest findings (in 3 years) of lung PMN and systematically collated it from basic research to clinical application, which clearly exhibited the influences of the primary tumor, stromal, and bone marrow-derived cells (BMDCs) and associated molecules in the formation of lung PMN.


Asunto(s)
Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/patología , Pulmón/patología , Citocinas , Biomarcadores
3.
iScience ; 26(12): 108484, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38094246

RESUMEN

Fibrosis disrupts tissue balance and links to severe illnesses, impairing organ function and, in some cases, even fatality. The interaction between M2 macrophages and fibroblasts is vital for tissue equilibrium. Transforming growth factor ß1 (TGF-ß1) released by M2 macrophages plays a central role in fibrosis, regulating fibroblast activity and extracellular matrix metabolism. Targeting TGF-ß1 is key to fibrosis treatment. In our study using three fibroblast cell lines, we reveal that the M2 macrophage transcription factor SP1 enhances binding to the TGF-ß1 promoter motif, promoting TGF-ß1 transcription and activating fibroblasts (This process does not involve changes in DNA methylation levels surrounding the motif sequence). The zinc fingers in SP1's DNA-binding domain 3 are crucial for this binding. In vivo, targeting SP1 in rat ligaments significantly reduces extracellular matrix accumulation. Our findings highlight SP1 as a promising target for regulating tissue extracellular matrix and combating fibrosis.

4.
Front Cardiovasc Med ; 10: 1267525, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37915739

RESUMEN

Background: Recently, attention has been paid to the protective properties of active ingredients in Salvia miltiorrhiza (AISM) against organ toxicity induced by chemotherapy drugs. Purpose of the present systematic review is to evaluate the chemoprotective effects and mechanisms of AISM on in vitro and in vivo models of doxorubicin-induced cardiotoxicity (DIC). Methods: According to the PRISMA guideline, the current systematic review was conducted in the Web of Science, PubMed, Embase, and the Cochrane Library to collect all relevant in vitro and in vivo studies on "the role of AISM on DIC" published up until May 2023. The SYRCLE's tool was used to identify potential risk of bias. Results: Twenty-two eligible articles were included in this systematic review. Eleven types of active ingredients in Salvia miltiorrhiza were used for DIC, which have the following effects: improvement of physical signs and biochemical indicators, reduction of cardiac function damage caused by DIC, protection of heart tissue structure, enhancement of myocardial cell viability, prevention of cardiomyocyte apoptosis, increase of the chemosensitivity of cancer cells to Doxorubicin, etc. The cardioprotective mechanism of AISM involves inhibiting apoptosis, attenuating oxidative stress, suppressing endoplasmic reticulum (ER) stress, decreasing inflammation, improving mitochondrial structure and function, affecting cellular autophagy and calcium homeostasis. The quality scores of included studies ranged from 4 to 7 points (a total of 10 points), according to SYRCLE's risk of bias tool. Conclusion: This systematic review demonstrated that AISM have chemoprotective effects on DIC in vivo and in vitro models through several main mechanisms such as anti-apoptosis, antioxidant effects, anti-ER stress, and anti-inflammatory.

5.
Sci Adv ; 8(19): eabn6045, 2022 05 13.
Artículo en Inglés | MEDLINE | ID: mdl-35559677

RESUMEN

Biosilicification-the formation of biological structures composed of silica-has a wide distribution among eukaryotes; it plays a major role in global biogeochemical cycles, and has driven the decline of dissolved silicon in the oceans through geological time. While it has long been thought that eukaryotes are the only organisms appreciably affecting the biogeochemical cycling of Si, the recent discoveries of silica transporter genes and marked silicon accumulation in bacteria suggest that prokaryotes may play an underappreciated role in the Si cycle, particularly in ancient times. Here, we report a previously unidentified magnetotactic bacterium that forms intracellular, amorphous silica globules. This bacterium, phylogenetically affiliated with the phylum Nitrospirota, belongs to a deep-branching group of magnetotactic bacteria that also forms intracellular magnetite magnetosomes and sulfur inclusions. This contribution reveals intracellularly controlled silicification within prokaryotes and suggests a previously unrecognized influence on the biogeochemical Si cycle that was operational during early Earth history.


Asunto(s)
Magnetosomas , Silicio , Bacterias/genética , Eucariontes , Óxido Ferrosoférrico , Magnetosomas/genética , Dióxido de Silicio
6.
Artículo en Inglés | MEDLINE | ID: mdl-35356244

RESUMEN

Background: Lung metastasis of malignant tumor signifies worse prognosis and immensely deteriorates patients' life quality. Spatholobi Caulis (SC) has been reported to reduce lung metastasis, but the mechanism remains elusive. Methods: The active components and corresponding targets of SC were obtained from the Traditional Chinese Medicine Database and Analysis Platform (TCMSP) database and the SwissTargetPrediction database. The disease targets were acquired from DisGeNET and GeneCards databases. Venn map was composed to figure out intersection targets by using R. The PPI network was constructed through STRING and Cytoscape, and MCODE plug-in was used to sift hub targets. Gene Ontology (GO)-Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was carried out by utilizing clusterProfiler package (R3.6.1) with adjusted P value <0.05. Network of SC-active components-intersection targets-KEGG pathway was accomplished with Cytoscape. Molecular docking between hub targets and active components was performed, analyzed, and visualized by AutoDockTools, AutoDock Vina, PLIP Web tool, and PYMOL. Results: 24 active components and 123 corresponding targets were screened, and the number of disease targets and intersection targets was 1074 and 47, respectively. RELA, JUN, MAPK1, MAPK14, STAT3, IL-4, ESR1, and TP53 were the 8 hub targets. GO analysis and KEGG analysis elucidated that SC could ameliorate lung metastasis mainly by intervening oxidative stress, AGE-RAGE signaling pathway, and microRNAs in cancer. All 8 hub targets were proven to combine successfully with active components of SC. Conclusion: Inflammation is the core factor that integrates all these targets, biological process, and signaling pathways, which indicates that SC prevents or reduces lung metastasis mainly by dispelling inflammation.

7.
Oncol Lett ; 23(5): 141, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35340557

RESUMEN

Chemotherapy dose intensity is a momentous parameter of antitumor clinical medication. In certain clinical trials, the actual application dose of the chemotherapeutic drugs is frequently different from the prescribed dose. The chemotherapy dose intensity completed in different trials is also variable, which has an impact on the treatment efficacy, disease prognosis and patient safety. When these agents are tested in the population, chemotherapy reduction and delay or failure to complete the planned cycle constantly occur due to age, performance status, adverse reactions and other reasons, resulting in the modification of the chemotherapy dose intensity. The present review analyzed the correlation between the chemotherapy dose intensity and the incidence of adverse reactions, the treatment efficacy and disease prognosis in clinical trials of metastatic colorectal cancer. Moreover, the clinical applications of chemotherapy dose intensity were discussed. Based on individual differences, the present review analyzed the clinical trials that examined the efficacy of the chemotherapy dose intensity in different patient populations. The conclusions suggested that different populations require a specific dose intensity to reduce treatment toxicity without affecting the curative effect.

8.
Neoplasma ; 68(6): 1132-1138, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34779643

RESUMEN

Prostate cancer (PCa) is one of the most common malignancies in men worldwide, and metastatic castrate-resistant prostate cancer (mCRPC) has shown a poor prognosis. Although chemotherapy and androgen deprivation therapy (ADT) have improved clinical outcomes, the median survival (MS) of patients with mCRPC is still less than 2 years. With the development of poly adenosine diphosphate-ribose polymerase inhibitor (PARPi), the treatment strategy for patients with mCRPC has markedly evolved. Olaparib, a type of PARPi that can selectively induce synthetic lethality in cancer cells with homologous recombination (HR) deficiencies, was the first type of PARPi approved for treating patients with mCRPC harboring mutations in HR repair (HRR) genes. This review discusses and summarizes the latest progress on therapeutic mechanisms, monotherapy, combination therapy, and adverse events of Olaparib.


Asunto(s)
Antagonistas de Andrógenos , Neoplasias de la Próstata Resistentes a la Castración , Antagonistas de Andrógenos/uso terapéutico , Humanos , Masculino , Ftalazinas/uso terapéutico , Piperazinas , Inhibidores de Poli(ADP-Ribosa) Polimerasas/uso terapéutico , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico
9.
Artículo en Inglés | MEDLINE | ID: mdl-33628320

RESUMEN

Cinobufotalin injection is a water-soluble preparation extracted from the skin secretion of Bufo bufo gargarizans Cantor or B. melanotictus Schneider, which has been widely used as an adjuvant treatment in lung cancer patients. This study aimed to evaluate the clinical efficacy and safety of cinobufotalin (PubChem CID: 259776) injection as an adjunctive treatment for lung cancer. We designed a meta-analysis that performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We aim to include randomized controlled trials by systematically searching the PubMed, EMBASE, CNKI, Wanfang database, VIP, CBM, the Cochrane Central Register of Controlled Trials, and Chinese Clinical Trial Registry from inception to Mar 1, 2020, comparing the difference between the use of cinobufotalin injection as an adjunctive treatment and a control group without cinobufotalin injection. The objective response rate (ORR) and quality of life (QOL) will be defined as the primary outcomes, and the disease control rate (DCR) and adverse events will be defined as the secondary outcomes. We included 21 articles with 1735 cases of lung cancer patients. Comparison results show that combining with cinobufotalin injection can improve ORR (OR = 1.77, 95% CI [1.43, 2.21], P < 0.001), with low heterogeneity (P = 0.94, I 2 = 0%); DCR (OR = 2.20, 95% CI [1.70, 2.85], P < 0.001), with low heterogeneity (P = 0.60, I 2 = 0%); KPS score (OR = 3.10, 95% CI [2.23, 4.32], P < 0.001), with low heterogeneity (P = 0.85, I 2 = 0%); and the effect of pain relief (OR = 2.68, 95% CI [1.30, 5.55], P = 0.008), with low heterogeneity (P = 0.72, I 2 = 0%). Low-to-moderate evidence shows that cinobufotalin injection combined with chemotherapy can significantly increase ORR, DCR, QOL, and the effect of pain relief. Meanwhile, cinobufotalin injection did not bring additional adverse events such as hematological toxicity, gastrointestinal toxicity, cardiotoxicity, hepatotoxicity, and nephrotoxicity; however, multicenter, large-sample, high-quality clinical research results are still needed to reveal the therapeutic effect of cinobufotalin injection in small-cell lung cancer (PROSPERO registration number: CRD42020170052).

10.
Artículo en Inglés | MEDLINE | ID: mdl-32802118

RESUMEN

BACKGROUND: Ginseng, a traditional Chinese medicine, was used to prevent and treat many diseases such as diabetes, inflammation, and cancer. In recent years, there are some reports about the treatment of lung adenocarcinoma with ginseng monomer compounds, but there is no systematic study on the related core targets and mechanism of ginseng in the treatment of lung adenocarcinoma up to now. Therefore, this study systematically and comprehensively studied the molecular mechanism of ginseng in the treatment of lung adenocarcinoma based on network pharmacology and further proved the potential targets by A549 cell experiments for the first time. METHODS: The targets of disease and drug were obtained from Gene database. Subsequently, the compound-target network was constructed, and the core potential targets were screened out by plug-in into Cytoscape. Furthermore, the core targets and mechanism of ginseng in the treatment of lung adenocarcinoma were verified by MTT test, cell scratch test, immunohistochemistry, and qRT-PCR. RESULTS: 1791 disease targets and 144 drug targets were obtained by searching the Gene database. Meanwhile, 15 core targets were screened out: JUN, MAPK8, PTGS2, CASP3, VEGFA, MMP9, AKT1, TNF, FN1, FOS, MMP782, IL-1ß, IL-2, ICAM1, and HMOX1. The results of cell experiments indicate that ginseng could treat lung adenocarcinoma by cell proliferation, migration, and apoptosis. In addition, according to the results of the 15 core targets by qRT-PCR, JUN, IL-1ß, IL-2, ICAM1, HMOX1, MMP9, and MMP2 are upregulated core targets, while PTGS2 and TNF are downregulated core targets. CONCLUSION: This study systematically and comprehensively studied 15 core targets by network pharmacology for the first time. Subsequently, it is verified that 9 core targets for ginseng treatment of lung adenocarcinoma, namely, JUN, IL-1ß, IL-2, ICAM1, HMOX1, MMP9, MMP2, PTGS2, and TNF, are closely related to the proliferation, migration, and apoptosis of lung adenocarcinoma cells. This study has reference value for the clinical application of ginseng in the treatment of lung adenocarcinoma.

11.
Medicine (Baltimore) ; 99(21): e20097, 2020 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-32481276

RESUMEN

BACKGROUND: Total knee arthroplasty (TKA) is one of the most common orthopedic procedures. However, the decision to resurface the patella during a primary TKA remains controversial. Therefore, a systematic review and meta-analysis were conducted to determine whether patellar resurfacing is needed in primary total knee arthroplasty. METHODS: A systematic literature research will be conducted in 7 databases including PubMed, Embase, Cochrane Library website, ClinicalTrials.gov databases, Chinese National Knowledge Infrastructure Database, Wanfang database, and VIP database for Chinese Technical Periodicals. The quality of studies will be assessed according to Cochrane risk of bias tool and Methodological index for non-randomized studies (MINORS) scale. The level of the evidence will be estimated by grading of recommendations assessment, development, and evaluation system. Data analysis and synthesis will be completed by the Review Manager 5.3. CONCLUSIONS: The conclusion of this study will provide clinicians performing TKA with a recommendation whether to conduct patellar resurfacing and further guide the clinical decision-making.PROSPERO registration number: CRD42019129711.


Asunto(s)
Artroplastia de Reemplazo de Rodilla/métodos , Rótula/cirugía , Toma de Decisiones Clínicas , Humanos , Metaanálisis como Asunto , Revisiones Sistemáticas como Asunto
12.
Medicine (Baltimore) ; 99(17): e19761, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32332614

RESUMEN

The objective of this review is to systematically evaluate the short-term efficacy of mud therapy in the treatment of knee osteoarthritis (KOA).Randomized controlled trials, in which treatment of KOA is mud therapy, were included by systematically searching the PubMed, Embase, and the Cochrane Library databases.According to inclusion criteria and searching method, 11 articles, containing a total of 1106 patients, were included in the study. Our results showed significant differences in visual analog scale pain score and Western Ontario and McMaster Universities Osteoarthritis Index (pain, stiffness, function). In addition, the heterogeneity of study included is lower (I < 25%).According to the results of this meta-analysis, mud therapy can effectively alleviate the pain and improve joint function for KOA.


Asunto(s)
Peloterapia/normas , Osteoartritis de la Rodilla/terapia , Factores de Tiempo , Humanos , Peloterapia/métodos , Osteoartritis de la Rodilla/psicología , Resultado del Tratamiento
13.
Mol Med Rep ; 20(3): 2199-2208, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31257520

RESUMEN

Small­cell lung cancer (SCLC) is a type of lung cancer with early metastasis, and high recurrence and mortality rates. The molecular mechanism is still unclear and further research is required. The aim of the present study was to examine the pathogenesis and potential molecular markers of SCLC by comparing the differential expression of mRNA and microRNA (miRNA) between SCLC tissue and normal lung tissue. A transcriptome sequencing dataset (GSE6044) and a non­coding RNA sequence dataset (GSE19945) were downloaded from the Gene Expression Omnibus (GEO) database. In total, 451 differentially expressed genes (DEGs) and 134 differentially expressed miRNAs (DEMs) were identified using the R limma software package and the GEO2R tool of the GEO, respectively. The Gene Ontology function was significantly enriched for 28 terms, and the Kyoto Encyclopedia of Genes and Genomes database had 19 enrichment pathways, mainly related to 'cell cycle', 'DNA replication' and 'oocyte meiosis mismatch repair'. The protein­protein interaction network was constructed using Cytoscape software to identify the molecular mechanisms of key signaling pathways and cellular activities in SCLC. The 1,402 miRNA­gene pairs encompassed 602 target genes of the DEMs using miRNAWalk, which is a bioinformatics platform that predicts DEM target genes and miRNA­gene pairs. There were 19 overlapping genes regulated by 32 miRNAs between target genes of the DEMs and DEGs. Bioinformatics analysis may help to better understand the role of DEGs, DEMs and miRNA­gene pairs in cell proliferation and signal transduction. The related hub genes may be used as biomarkers for the diagnosis and prognosis of SCLC, and as potential drug targets.


Asunto(s)
Regulación Neoplásica de la Expresión Génica , Redes Reguladoras de Genes , Neoplasias Pulmonares/genética , MicroARNs/genética , ARN Mensajero/genética , Carcinoma Pulmonar de Células Pequeñas/genética , Biología Computacional , Perfilación de la Expresión Génica , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos
14.
Sci Rep ; 4: 6868, 2014 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-25359610

RESUMEN

Investigation of climatic conditions prior to the Sturtian glaciations is critical to understanding the trigger mechanism for the series of Neoproterozoic global glaciations. In this study, we report high-resolution chemical index of alteration (CIA) records in the sediments of South China prior to the Sturtian glaciation (820~720 Ma). Our results showed there occurred multiple climate cooling before the Sturtian glaciations in South China: (1) a series of episodic and possibly global climate cooling periods from ca. 750 Ma to 725 Ma, which also caused some diachronous regional glaciations; (2) a permanent climate cooling period between ca. 800 Ma and 770 Ma, probably contemporaneous to the global "Bitter Springs stage" δ(13)C negative excursion; (3) a climate cooling period between ca. 815 Ma and 810 Ma. The three stages of climate cooling are also supported by their correspondence to previously reported extremely low δ(18)O records of igneous/metamorphic minerals from South China. These climate cooling periods also coincide with the magmatism and rifting events in South China. We argue that tectonic movements were the primary control on the climate cooling before the Neoproterozoic global glaciations.

15.
Nature ; 477(7365): 448-51, 2011 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-21900895

RESUMEN

The chemical composition of the ocean changed markedly with the oxidation of the Earth's surface, and this process has profoundly influenced the evolutionary and ecological history of life. The early Earth was characterized by a reducing ocean-atmosphere system, whereas the Phanerozoic eon (less than 542 million years ago) is known for a stable and oxygenated biosphere conducive to the radiation of animals. The redox characteristics of surface environments during Earth's middle age (1.8-1 billion years ago) are less well known, but it is generally assumed that the mid-Proterozoic was home to a globally sulphidic (euxinic) deep ocean. Here we present iron data from a suite of mid-Proterozoic marine mudstones. Contrary to the popular model, our results indicate that ferruginous (anoxic and Fe(2+)-rich) conditions were both spatially and temporally extensive across diverse palaeogeographic settings in the mid-Proterozoic ocean, inviting new models for the temporal distribution of iron formations and the availability of bioessential trace elements during a critical window for eukaryotic evolution.


Asunto(s)
Hierro/análisis , Agua de Mar/química , Evolución Biológica , Sedimentos Geológicos/química , Historia Antigua , Hierro/química , Océanos y Mares , Azufre/análisis , Azufre/química , Isótopos de Azufre , Factores de Tiempo
16.
Science ; 328(5974): 80-3, 2010 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-20150442

RESUMEN

The Ediacaran Period (635 to 542 million years ago) was a time of fundamental environmental and evolutionary change, culminating in the first appearance of macroscopic animals. Here, we present a detailed spatial and temporal record of Ediacaran ocean chemistry for the Doushantuo Formation in the Nanhua Basin, South China. We find evidence for a metastable zone of euxinic (anoxic and sulfidic) waters impinging on the continental shelf and sandwiched within ferruginous [Fe(II)-enriched] deep waters. A stratified ocean with coeval oxic, sulfidic, and ferruginous zones, favored by overall low oceanic sulfate concentrations, was maintained dynamically throughout the Ediacaran Period. Our model reconciles seemingly conflicting geochemical redox conditions proposed previously for Ediacaran deep oceans and helps to explain the patchy temporal record of early metazoan fossils.


Asunto(s)
Evolución Biológica , Fósiles , Sedimentos Geológicos/química , Oxígeno/análisis , Agua de Mar/química , Animales , Carbonatos/análisis , China , Compuestos Ferrosos/análisis , Sulfuro de Hidrógeno , Hierro , Océanos y Mares , Oxidación-Reducción , Sulfatos/análisis
17.
Proc Natl Acad Sci U S A ; 105(9): 3197-202, 2008 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-18299566

RESUMEN

Recent geochemical data from Oman, Newfoundland, and the western United States suggest that long-term oxidation of Ediacaran oceans resulted in progressive depletion of a large dissolved organic carbon (DOC) reservoir and potentially triggered the radiation of acanthomorphic acritarchs, algae, macroscopic Ediacara organisms, and, subsequently, motile bilaterian animals. However, the hypothesized coupling between ocean oxidation and evolution is contingent on the reliability of continuous geochemical and paleontological data in individual sections and of intercontinental correlations. Here we report high-resolution geochemical data from the fossil-rich Doushantuo Formation (635-551 Ma) in South China that confirm trends from other broadly equivalent sections and highlight key features that have not been observed in most sections or have received little attention. First, samples from the lower Doushantuo Formation are characterized by remarkably stable delta(13)C(org) (carbon isotope composition of organic carbon) values but variable delta(34)S(CAS) (sulfur isotope composition of carbonate-associated sulfate) values, which are consistent with a large isotopically buffered DOC reservoir and relatively low sulfate concentrations. Second, there are three profound negative delta(13)C(carb) (carbon isotope composition of carbonate) excursions in the Ediacaran Period. The negative delta(13)C(carb) excursions in the middle and upper Doushantuo Formation record pulsed oxidation of the deep oceanic DOC reservoir. The oxidation events appear to be coupled with eukaryote diversity in the Doushantuo basin. Comparison with other early Ediacaran basins suggests spatial heterogeneity of eukaryote distribution and redox conditions. We hypothesize that the distribution of early Ediacaran eukaryotes likely tracked redox conditions and that only after approximately 551 Ma (when Ediacaran oceans were pervasively oxidized) did evolution of oxygen-requiring taxa reach global distribution.


Asunto(s)
Evolución Biológica , Oxígeno , Paleontología/métodos , Agua de Mar/química , Animales , Carbono , Isótopos de Carbono , Fósiles , Sedimentos Geológicos , Océanos y Mares
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