Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 105
Filtrar
1.
Toxicol Sci ; 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34609516

RESUMO

Particulate matter (PM) causes adverse developmental outcomes following prenatal exposure, but the underlying biological mechanisms remain uncertain. Here we elucidate the effects of diesel exhaust ultrafine particle (UFP) exposure during pregnancy on placental and fetal development. Time-mated C57Bl/6n mice were gestationally exposed to UFPs at a low dose (LD, 100 µg/m3) or high dose (HD, 500 µg/m3) for 6 hours daily. Phenotypic effects on fetuses and placental morphology at gestational day (GD) of 18.5 were evaluated, and RNA sequencing was characterized for transcriptomic changes in placental tissue from male and female offspring. A significant decrease in average placental weights and crown to rump lengths was observed in female offspring in the LD exposure group. Gestational UFP exposure altered placental morphology in a dose and sex-specific manner. Average female decidua areas were significantly greater in the LD and HD groups. Maternal lacunae mean areas were increased in the female LD group, whereas fetal blood vessel mean areas were significantly greater in the male LD and HD groups. RNA sequencing indicated several disturbed cellular functions related to lipid metabolism, which were most pronounced in the LD group and especially in female placental tissue. Our findings demonstrate the vulnerability of offspring exposed to UFPs during pregnancy, highlighting sex-specific effects and emphasizing the importance of mitigating PM exposure to prevent adverse health outcomes.

3.
Environ Health Prev Med ; 26(1): 72, 2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34253165

RESUMO

BACKGROUND: Particulate matter (PM), a major component of ambient air pollution, accounts for a substantial burden of diseases and fatality worldwide. Maternal exposure to PM during pregnancy is particularly harmful to children's health since this is a phase of rapid human growth and development. METHOD: In this review, we synthesize the scientific evidence on adverse health outcomes in children following prenatal exposure to the smallest toxic components, fine (PM2.5) and ultrafine (PM0.1) PM. We highlight the established and emerging findings from epidemiologic studies and experimental models. RESULTS: Maternal exposure to fine and ultrafine PM directly and indirectly yields numerous adverse birth outcomes and impacts on children's respiratory systems, immune status, brain development, and cardiometabolic health. The biological mechanisms underlying adverse effects include direct placental translocation of ultrafine particles, placental and systemic maternal oxidative stress and inflammation elicited by both fine and ultrafine PM, epigenetic changes, and potential endocrine effects that influence long-term health. CONCLUSION: Policies to reduce maternal exposure and health consequences in children should be a high priority. PM2.5 levels are regulated, yet it is recognized that minority and low socioeconomic status groups experience disproportionate exposures. Moreover, PM0.1 levels are not routinely measured or currently regulated. Consequently, preventive strategies that inform neighborhood/regional planning and clinical/nutritional recommendations are needed to mitigate maternal exposure and ultimately protect children's health.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/efeitos adversos , Exposição Materna/efeitos adversos , Material Particulado/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Adulto , Poluição do Ar/prevenção & controle , Animais , Doenças Cardiovasculares/induzido quimicamente , Saúde da Criança , Pré-Escolar , Modelos Animais de Doenças , Doenças do Sistema Endócrino/induzido quimicamente , Epigenômica , Feminino , Humanos , Doenças do Sistema Imunitário/induzido quimicamente , Lactente , Recém-Nascido , Masculino , Doenças do Sistema Nervoso/induzido quimicamente , Estresse Oxidativo , Tamanho da Partícula , Placenta , Gravidez , Resultado da Gravidez/epidemiologia , Doenças Respiratórias/induzido quimicamente , Adulto Jovem
4.
Environ Sci Technol ; 55(13): 8592-8603, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34137267

RESUMO

Photooxidation of volatile organic compounds (VOCs) produces secondary organic aerosol (SOA) and light-absorbing brown carbon (BrC) via multiple reaction steps/pathways, reflecting significant chemical complexity relevant to gaseous oxidation and subsequent gas-to-particle conversion. Toluene is an important VOC under urban conditions, but the fundamental chemical mechanism leading to SOA formation remains uncertain. Here, we elucidate multigeneration SOA production from toluene by simultaneously tracking the evolutions of gas-phase oxidation and aerosol formation in a reaction chamber. Large size increase and browning of monodisperse sub-micrometer seed particles occur shortly after initiating oxidation by hydroxyl radical (OH) at 10-90% relative humidity (RH). The evolution in gaseous products and aerosol properties (size/density/optical properties) and chemical speciation of aerosol-phase products indicate that the aerosol growth and browning result from earlier generation products consisting dominantly of dicarbonyl and carboxylic functional groups. While volatile dicarbonyls engage in aqueous reactions to yield nonvolatile oligomers and light-absorbing nitrogen heterocycles/heterochains (in the presence of NH3) at high RH, organic acids contribute to aerosol carboxylates via ionic dissociation or acid-base reaction in a wide RH range. We conclude that toluene contributes importantly to SOA/BrC formation from dicarbonyls and organic acids because of their prompt and high yields from photooxidation and unique functionalities for participation in aerosol-phase reactions.


Assuntos
Tolueno , Compostos Orgânicos Voláteis , Aerossóis , Gases , Oxirredução
5.
Environ Sci Technol ; 55(8): 4430-4439, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33721996

RESUMO

Large amounts of small α-dicarbonyls (glyoxal and methylglyoxal) are produced in the atmosphere from photochemical oxidation of biogenic isoprene and anthropogenic aromatics, but the fundamental mechanisms leading to secondary organic aerosol (SOA) and brown carbon (BrC) formation remain elusive. Methylglyoxal is commonly believed to be less reactive than glyoxal because of unreactive methyl substitution, and available laboratory measurements showed negligible aerosol growth from methylglyoxal. Herein, we present experimental results to demonstrate striking oligomerization of small α-dicarbonyls leading to SOA and BrC formation on sub-micrometer aerosols. Significantly more efficient growth and browning of aerosols occur upon exposure to methylglyoxal than glyoxal under atmospherically relevant concentrations and in the absence/presence of gas-phase ammonia and formaldehyde, and nonvolatile oligomers and light-absorbing nitrogen-heterocycles are identified as the dominant particle-phase products. The distinct aerosol growth and light absorption are attributed to carbenium ion-mediated nucleophilic addition, interfacial electric field-induced attraction, and synergetic oligomerization involving organic/inorganic species, leading to surface- or volume-limited reactions that are dependent on the reactivity and gaseous concentrations. Our findings resolve an outstanding discrepancy concerning the multiphase chemistry of small α-dicarbonyls and unravel a new avenue for SOA and BrC formation from atmospherically abundant, ubiquitous carbonyls and ammonia/ammonium sulfate.


Assuntos
Carbono , Glioxal , Aerossóis , Sulfato de Amônio , Aldeído Pirúvico
6.
Environ Sci Technol ; 55(4): 2189-2207, 2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33539077

RESUMO

Severe haze events with exceedingly high-levels of fine aerosols occur frequently over the past decades in the North China Plain (NCP), exerting profound impacts on human health, weather, and climate. The development of effective mitigation policies requires a comprehensive understanding of the haze formation mechanisms, including identification and quantification of the sources, formation, and transformation of the aerosol species. Haze evolution in this region exhibits distinct physical and chemical characteristics from clean to polluted periods, as evident from increasing stagnation and relative humidity, but decreasing solar radiation as well as explosive secondary aerosol formation. The latter is attributed to highly elevated concentrations of aerosol precursor gases and is reflected by rapid increases in the particle number and mass concentrations, both corresponding to nonequilibrium chemical processes. Considerable new knowledge has been acquired to understand the processes regulating haze formation, particularly in light of the progress in elucidating the aerosol formation mechanisms. This review synthesizes recent advances in understanding secondary aerosol formation, by highlighting several critical chemical/physical processes, that is, new particle formation and aerosol growth driven by photochemistry and aqueous chemistry as well as the interaction between aerosols and atmospheric stability. Current challenges and future research priorities are also discussed.


Assuntos
Poluentes Atmosféricos , Substâncias Explosivas , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Humanos , Material Particulado/análise
7.
Chemosphere ; 273: 129207, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33349467

RESUMO

Tertiary amines are one kind of identified amines in the atmosphere. Here, the atmospheric oxidation mechanism and kinetics of tertiary amines were investigated by using computational methods. As proxies of these amines, trimethylamine (TMA) and triethylamine (TEA) have been selected. Results indicate that N-containing peroxy radicals (NRO2⋅), which are key intermediates in ⋅OH initiated oxidation of TMA and TEA, can follow a so-called autoxidation mechanism (a chain reaction of H-shift followed by O2 addition) even on the condition of high NO/HO2⋅ concentration. Such unique mechanism can be ascribed to the ability of N-atom in facilitating the unimolecular H-shift of NRO2⋅ and the absence of H-atoms on N-atom. However, different from TMA reaction system, the pathway dissociating into fragmental products can compete with the autoxidation pathway for TEA system. More importantly, TEA reaction system cannot lead to the formation of products with high O/C ratio due to the autoxidation pathway terminated by the release of fragmental molecules. Such difference can be corroborated by previously observing lower secondary organic aerosol yield of TEA oxidation than that of TMA oxidation. The unveiled mechanism enhances current understanding on atmospheric fate of amines and autoxidation mechanism.


Assuntos
Aminas , Atmosfera , Aerossóis , Cinética , Oxirredução
8.
Sci Total Environ ; 748: 141560, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32798884

RESUMO

The outbreak of the novel coronavirus disease (COVID-19) severely threatens the public health worldwide, but the transmission mechanism and the effectiveness of mitigation measures remain uncertain. Here we assess the role of airborne transmission in spreading the disease and the effectiveness of face covering in preventing inter-human transmission for the top-fifteen infected U.S. states during March 1 and May 18, 2020. For all fifteen states, the curve of total confirmed infections exhibits an initial sub-exponential growth and a subsequent linear growth after implementing social distancing/stay-at-home orders. The linearity extends one to two months for the six states without mandated face covering and to the onset of mandated face covering for the other nine states with this measure, reflecting a dynamic equilibrium between first-order transmission kinetics and intervention. For the states with mandated face covering, significant deviation from this linearity and curve flattening occur after the onset of this measure for seven states, with exceptions for two states. Most states exhibit persistent upward trends in the daily new infections after social distancing/stay-at-home orders, while reversed downward or slowing trends occur for eight states after implementing mandated face covering. The inadequacy of social distancing and stay-at-home measures alone in preventing inter-human transmission is reflected by the continuous linear growth in the total infection curve after implementing these measures, which is mainly driven by airborne transmission. We estimate that the number of the total infections prevented by face covering reaches ~252,000 on May 18 in seven states, which is equivalent to ~17% of the total infections in the nation. We conclude that airborne transmission and face covering play the dominant role in spreading the disease and flattening the total infection curve, respectively. Our findings provide policymakers and the public with compelling evidence that universal face covering, in conjunction with social distancing and hand hygiene, represents the maximal protection against inter-human transmission and the combination of these intervention measures with rapid and extensive testing as well as contact tracing is crucial in containing the COVID-19 pandemic.


Assuntos
Betacoronavirus , Infecções por Coronavirus , Coronavirus , Pandemias , Pneumonia Viral , COVID-19 , Humanos , SARS-CoV-2 , Estados Unidos/epidemiologia
9.
Proc Natl Acad Sci U S A ; 117(24): 13294-13299, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32493751

RESUMO

Secondary organic aerosol (SOA) represents a major constituent of tropospheric fine particulate matter, with profound implications for human health and climate. However, the chemical mechanisms leading to SOA formation remain uncertain, and atmospheric models consistently underpredict the global SOA budget. Small α-dicarbonyls, such as methylglyoxal, are ubiquitous in the atmosphere because of their significant production from photooxidation of aromatic hydrocarbons from traffic and industrial sources as well as from biogenic isoprene. Current experimental and theoretical results on the roles of methylglyoxal in SOA formation are conflicting. Using quantum chemical calculations, we show cationic oligomerization of methylglyoxal in aqueous media. Initial protonation and hydration of methylglyoxal lead to formation of diols/tetrol, and subsequent protonation and dehydration of diols/tetrol yield carbenium ions, which represent the key intermediates for formation and propagation of oligomerization. On the other hand, our results reveal that the previously proposed oligomerization via hydration for methylglyoxal is kinetically and thermodynamically implausible. The carbenium ion-mediated mechanism occurs barrierlessly on weakly acidic aerosols and cloud/fog droplets and likely provides a key pathway for SOA formation from biogenic and anthropogenic emissions.

10.
Sci Rep ; 10(1): 10295, 2020 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-32581317

RESUMO

Silicon (Si) plays an important role in plant nutrient capture and absorption, and also promotes plant mechanical strength and light interception in alpine meadows. In this study, we conducted a field experiment to examine the effect of nitrogen (N) application, with (N + Si) and without Si (N-only), on the potential for soil nutrient and the growth of grass and legume plant functional types (PFTs) in an alpine meadow. It was found that N + Si resulted in higher soil nutrient contents, leaf N and P concentrations, abundance and biomass of legume and grass PFTs than N-only. The aboveground biomass of grass (598 g m-2) and legume (12.68 g m-2) PFTs under 600 kg ha-1 ammonium nitrate (NH4NO3) per year addition with Si was significantly higher than that under the same level of N addition without Si (515 and 8.68 g m-2, respectively). The grass:legume biomass ratio did not differ significantly between the N + Si and N-only. This demonstrates that Si enhances N fertilization with apparently little effect on grass:legume ratio and increases plant-available nutrients, indicating that Si is essential for the plant community in alpine meadows.

11.
Proc Natl Acad Sci U S A ; 117(26): 14857-14863, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32527856

RESUMO

Various mitigation measures have been implemented to fight the coronavirus disease 2019 (COVID-19) pandemic, including widely adopted social distancing and mandated face covering. However, assessing the effectiveness of those intervention practices hinges on the understanding of virus transmission, which remains uncertain. Here we show that airborne transmission is highly virulent and represents the dominant route to spread the disease. By analyzing the trend and mitigation measures in Wuhan, China, Italy, and New York City, from January 23 to May 9, 2020, we illustrate that the impacts of mitigation measures are discernable from the trends of the pandemic. Our analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the pandemic trends in the three epicenters. This protective measure alone significantly reduced the number of infections, that is, by over 78,000 in Italy from April 6 to May 9 and over 66,000 in New York City from April 17 to May 9. Other mitigation measures, such as social distancing implemented in the United States, are insufficient by themselves in protecting the public. We conclude that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with simultaneous social distancing, quarantine, and contact tracing, represents the most likely fighting opportunity to stop the COVID-19 pandemic. Our work also highlights the fact that sound science is essential in decision-making for the current and future public health pandemics.


Assuntos
Infecções por Coronavirus/transmissão , Transmissão de Doença Infecciosa/estatística & dados numéricos , Exposição por Inalação/estatística & dados numéricos , Pneumonia Viral/transmissão , COVID-19 , Infecções por Coronavirus/epidemiologia , Transmissão de Doença Infecciosa/classificação , Transmissão de Doença Infecciosa/prevenção & controle , Humanos , Exposição por Inalação/prevenção & controle , Máscaras/estatística & dados numéricos , Pandemias , Pneumonia Viral/epidemiologia , Prevenção Primária/métodos , Prevenção Primária/estatística & dados numéricos , Quarentena/métodos , Quarentena/estatística & dados numéricos , Dispositivos de Proteção Respiratória/estatística & dados numéricos , Estados Unidos
12.
Environ Res ; 187: 109464, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32438096

RESUMO

BACKGROUND: Except for known cardiovascular risk factors, long-term exposure to environmental endocrine disruptors (EEDs) - a class of exogenous chemicals, or a mixture of chemicals, that can interfere with any aspect of hormone action - has been shown to increase the risk of cardiovascular diseases (CVDs), which are still controversial. OBJECTIVE: To conduct a comprehensive systematic review and meta-analysis to estimate the association between EEDs, including nonylphenol (NP), bisphenol A (BPA), polychlorinated biphenyl (PCB), organo-chlorine pesticide (OCP) and phthalate (PAE) exposure and CVD risk. METHODS: The heterogeneity between different studies was qualitatively and quantitatively evaluated using Q test and I2 statistical magnitude, respectively. Subgroup analysis was performed using chemical homologs - a previously unused grouping method - to extract data and perform meta-analysis to assess their exposure to CVD. RESULTS: Twenty-nine literatures were enrolled with a total sample size of 88891. The results indicated that exposure to PCB138 and PCB153 were the risk factors for CVD morbidity (odds ratio (OR) = 1.35, 95% confidence interval (CI): 1.10-1.66; OR = 1.35, 95% CI: 1.13-1.62). Exposure to organo-chlorine pesticide (OCP) (OR = 1.12, 95% CI: 1.00-1.24), as well as with phthalate (PAE) (OR = 1.11, 95% CI: 1.06-1.17) and BPA (OR = 1.19, 95% CI: 1.03-1.37) were positively associated with CVD risk, respectively. BPA exposure concentration had no correlation with total cholesterol (TC), or low-density lipoprotein (LDL), but exhibited a correlation with gender, waist circumference (WC), high-density lipoprotein (HDL), age, and body mass index (BMI) (standardized mean difference (SMD)) = 1.51; 95% CI: =(1.01-2.25); SMD = 0.16; 95% CI: (0.08-0.23); SMD = -0.19; 95% CI: (-0.27-0.12); SMD = -0.78; 95% CI: (-1.42-0.14); SMD = 0.08; 95% CI: (0.00-0.16). CONCLUSIONS: EED exposure is a risk factor for CVD. Long-term exposure to EEDs can influence cardiovascular health in humans. A possible synergistic effect may exist between the homologs. The mechanism of which needs to be further explored and demonstrated by additional prospective cohort studies, results of in vitro and in vivo analyses, as well as indices affecting CVD.


Assuntos
Doenças Cardiovasculares , Disruptores Endócrinos , Índice de Massa Corporal , Doenças Cardiovasculares/induzido quimicamente , Doenças Cardiovasculares/epidemiologia , Disruptores Endócrinos/toxicidade , Humanos , Estudos Prospectivos , Fatores de Risco
13.
PLoS One ; 15(4): e0231880, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32315365

RESUMO

BACKGROUND: Evidence has shown that deep learning computer aided detection (CADe) system achieved high overall detection accuracy for polyp detection during colonoscopy. AIM: The detection performance of CADe system on non-polypoid laterally spreading tumors (LSTs) and sessile serrated adenomas/polyps (SSA/Ps), with higher risk for malignancy transformation and miss rate, has not been exclusively investigated. METHODS: A previously validated deep learning CADe system for polyp detection was tested exclusively on LSTs and SSA/Ps. 1451 LST images from 184 patients were collected between July 2015 and January 2019, 82 SSA/Ps videos from 26 patients were collected between September 2018 and January 2019. The per-frame sensitivity and per-lesion sensitivity were calculated. RESULTS: (1) For LSTs image dataset, the system achieved an overall per-image sensitivity and per-lesion sensitivity of 94.07% (1365/1451) and 98.99% (197/199) respectively. The per-frame sensitivity for LST-G(H), LST-G(M), LST-NG(F), LST-NG(PD) was 93.97% (343/365), 98.72% (692/701), 85.71% (324/378) and 85.71% (6/7) respectively. The per-lesion sensitivity of each subgroup was 100.00% (71/71), 100.00% (64/64), 98.31% (58/59) and 80.00% (4/5). (2) For SSA/Ps video dataset, the system achieved an overall per-frame sensitivity and per-lesion sensitivity of 84.10% (15883/18885) and 100.00% (42/42), respectively. CONCLUSIONS: This study demonstrated that a local-feature-prioritized automatic CADe system could detect LSTs and SSA/Ps with high sensitivity. The per-frame sensitivity for non-granular LSTs and small SSA/Ps should be further improved.


Assuntos
Adenoma/diagnóstico , Colonoscopia , Neoplasias Colorretais/diagnóstico , Processamento de Imagem Assistida por Computador/métodos , Adenoma/patologia , Pólipos do Colo/patologia , Neoplasias Colorretais/patologia , Aprendizado Profundo , Humanos
15.
Proc Natl Acad Sci U S A ; 117(8): 3960-3966, 2020 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-32041887

RESUMO

Although regional haze adversely affects human health and possibly counteracts global warming from increasing levels of greenhouse gases, the formation and radiative forcing of regional haze on climate remain uncertain. By combining field measurements, laboratory experiments, and model simulations, we show a remarkable role of black carbon (BC) particles in driving the formation and trend of regional haze. Our analysis of long-term measurements in China indicates declined frequency of heavy haze events along with significantly reduced SO2, but negligibly alleviated haze severity. Also, no improving trend exists for moderate haze events. Our complementary laboratory experiments demonstrate that SO2 oxidation is efficiently catalyzed on BC particles in the presence of NO2 and NH3, even at low SO2 and intermediate relative humidity levels. Inclusion of the BC reaction accounts for about 90-100% and 30-50% of the sulfate production during moderate and heavy haze events, respectively. Calculations using a radiative transfer model and accounting for the sulfate formation on BC yield an invariant radiative forcing of nearly zero W m-2 on the top of the atmosphere throughout haze development, indicating small net climatic cooling/warming but large surface cooling, atmospheric heating, and air stagnation. This BC catalytic chemistry facilitates haze development and explains the observed trends of regional haze in China. Our results imply that reduction of SO2 alone is insufficient in mitigating haze occurrence and highlight the necessity of accurate representation of the BC chemical and radiative properties in predicting the formation and assessing the impacts of regional haze.

16.
Proc Natl Acad Sci U S A ; 117(7): 3427-3432, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-32015109

RESUMO

High levels of ultrafine particles (UFPs; diameter of less than 50 nm) are frequently produced from new particle formation under urban conditions, with profound implications on human health, weather, and climate. However, the fundamental mechanisms of new particle formation remain elusive, and few experimental studies have realistically replicated the relevant atmospheric conditions. Previous experimental studies simulated oxidation of one compound or a mixture of a few compounds, and extrapolation of the laboratory results to chemically complex air was uncertain. Here, we show striking formation of UFPs in urban air from combining ambient and chamber measurements. By capturing the ambient conditions (i.e., temperature, relative humidity, sunlight, and the types and abundances of chemical species), we elucidate the roles of existing particles, photochemistry, and synergy of multipollutants in new particle formation. Aerosol nucleation in urban air is limited by existing particles but negligibly by nitrogen oxides. Photooxidation of vehicular exhaust yields abundant precursors, and organics, rather than sulfuric acid or base species, dominate formation of UFPs under urban conditions. Recognition of this source of UFPs is essential to assessing their impacts and developing mitigation policies. Our results imply that reduction of primary particles or removal of existing particles without simultaneously limiting organics from automobile emissions is ineffective and can even exacerbate this problem.


Assuntos
Material Particulado/química , Emissões de Veículos/análise , Poluentes Atmosféricos/química , Oxirredução , Tamanho da Partícula , Temperatura
17.
Genome Biol Evol ; 12(1): 3725-3737, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31917411

RESUMO

Sympatric speciation remains a central focus of evolutionary biology. Although some evidence shows speciation occurring in this way, little is known about the gene expression evolution and the characteristics of population genetics as species diverge. Two closely related Gymnocypris fish (Gymnocypris chui and Gymnocypris scleracanthus), which come from a small glacier lake in the Tibetan Plateau, Lake Langcuo, exist a possible incipient sympatric adaptive ecological speciation. We generated large amounts of RNA-Seq data from multiple individuals and tissues from each of the two species and compared gene expression patterns and genetic polymorphisms between them. Ordination analysis separated samples by organ rather than by species. The degree of expression difference between organs within and between species was different. Phylogenetic analyses indicated that the two closely related taxa formed a monophyletic complex. Population structure analysis displayed two distinctly divergent clusters of G. chui and G. scleracanthus populations. By contrast, G. scleracanthus population genetic diversity is higher than that of G. chui. Considerable sites of the two populations were differentiated with a coefficient of FST = 0.25-0.50, implying that a small proportion of loci nevertheless exhibited deep divergence in two comparisons. Concomitantly, putatively selected genes during speciation revealed functional categories are enriched in bone morphogenesis, cell growth, neurogenetics, enzyme activity, and binding activity in G. chui population. In contrast, nutrition and localization were highlighted in G. scleracanthus. Collectively, morphological traits and dietary preference combine with genetic variation and expression variation, probably contributed to the incipient speciation of two sympatric populations.


Assuntos
Cyprinidae/genética , Especiação Genética , Transcriptoma , Animais , Camada de Gelo , Lagos , Especificidade de Órgãos , RNA-Seq , Especificidade da Espécie , Simpatria , Tibet
20.
Proc Natl Acad Sci U S A ; 116(24): 11590-11595, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31138695

RESUMO

Exposure to fine particulate matter (PM) during pregnancy is associated with high risks of birth defects/fatality and adverse long-term postnatal health. However, limited mechanistic data are available to assess the detailed impacts of prenatal PM exposure. Here we evaluate fine PM exposure during pregnancy on prenatal/postnatal organogenesis in offspring and in predisposing metabolic syndrome for adult life. Between days 0 and 18 of gestation, two groups of adult female rats (n = 10 for each) were placed in a dual-exposure chamber device, one with clean ambient air (∼3 µg·m-3) and the other with ambient air in the presence of 100 to 200 µg·m-3 of ultrafine aerosols of ammonium sulfate. At birth (postnatal day 0, PND0), four males and four females were selected randomly from each litter to be nursed by dams, whereas tissues were collected from the remaining pups. At PND21, tissues were collected from two males and two females, whereas the remaining pups were fed either a high- or low-fat diet until PND105, when tissues were obtained for biochemical and physiological analyses. Maternal exposure to fine PM increased stillbirths; reduced gestation length and birth weight; increased concentrations of glucose and free fatty acids in plasma; enhanced lipid accumulation in the liver; and decreased endothelium-dependent relaxation of aorta. This lead to altered organogenesis and predisposed progeny to long-term metabolic defects in an age-, organ-, and sex-specific manner. Our results highlight the necessity to develop therapeutic strategies to remedy adverse health effects of maternal PM exposure on conceptus/postnatal growth and development.


Assuntos
Exposição Materna/efeitos adversos , Síndrome Metabólica/induzido quimicamente , Organogênese/efeitos dos fármacos , Material Particulado/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal/patologia , Poluição do Ar/efeitos adversos , Animais , Peso ao Nascer/efeitos dos fármacos , Suscetibilidade a Doenças/sangue , Suscetibilidade a Doenças/metabolismo , Suscetibilidade a Doenças/patologia , Exposição Ambiental/efeitos adversos , Ácidos Graxos/sangue , Feminino , Glucose/metabolismo , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/metabolismo , Síndrome Metabólica/patologia , Organogênese/fisiologia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/sangue , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Ratos , Ratos Sprague-Dawley
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...