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1.
PLoS One ; 15(7): e0235755, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32649709

RESUMO

As a widespread phytoplankton species, the coccolithophore Gephyrocapsaoceanica has a significant impact on the global biogeochemical cycle through calcium carbonate precipitation and photosynthesis. As global change continues, marine phytoplankton will experience alterations in multiple parameters, including temperature, pH, CO2, and nitrogen sources, and the interactive effects of these variables should be examined to understand how marine organisms will respond to global change. Here, we show that the specific growth rate of G. oceanica is reduced by elevated CO2 (1000 µatm) in [Formula: see text]-grown cells, while it is increased by high CO2 in [Formula: see text]-grown ones. This difference was related to intracellular metabolic regulation, with decreased cellular particulate organic carbon and particulate organic nitrogen (PON) content in the [Formula: see text] and high CO2 condition compared to the low CO2 condition. In contrast, no significant difference was found between the high and low CO2 levels in [Formula: see text] cultures (p > 0.05). The temperature increase from 20°C to 25°C increased the PON production rate, and the enhancement was more prominent in [Formula: see text] cultures. Enhanced or inhibited particulate inorganic carbon production rate in cells supplied with [Formula: see text] relative to [Formula: see text] was observed, depending on the temperature and CO2 condition. These results suggest that a greater disruption of the organic carbon pump can be expected in response to the combined effects of increased [Formula: see text]/[Formula: see text] ratio, temperature, and CO2 level in the oceans of the future. Additional experiments conducted under nutrient limitation conditions are needed before we can extrapolate our findings to the global oceans.


Assuntos
Dióxido de Carbono/farmacologia , Haptófitas/crescimento & desenvolvimento , Nitrogênio/farmacologia , Dióxido de Carbono/análise , Haptófitas/efeitos dos fármacos , Nitrogênio/análise , Temperatura
2.
Med Sci (Paris) ; 36(4): 382-388, 2020 Apr.
Artigo em Francês | MEDLINE | ID: mdl-32356715

RESUMO

As burden of chronic respiratory diseases is constantly increasing, improving in vitro lung models is essential in order to reproduce as closely as possible the complex pulmonary architecture, responsible for oxygen uptake and carbon dioxide clearance. The study of diseases that affect the respiratory system has benefited from in vitro reconstructions of the respiratory epithelium with inserts in air/liquid interface (2D) or in organoids able to mimic up to the arborescence of the respiratory tree (3D). Recent development in the fields of pluripotent stem cells-derived organoids and genome editing technologies has provided new insights to better understand pulmonary diseases and to find new therapeutic perspectives.


Assuntos
Técnicas de Cultura de Células , Pulmão/citologia , Organoides/citologia , Células Epiteliais Alveolares/citologia , Células Epiteliais Alveolares/fisiologia , Animais , Bioengenharia/métodos , Bioengenharia/tendências , Dióxido de Carbono/farmacologia , Dióxido de Carbono/fisiologia , Técnicas de Cultura de Células/métodos , Técnicas de Cultura de Células/tendências , Células Cultivadas , Edição de Genes/métodos , Edição de Genes/tendências , Humanos , Pulmão/patologia , Pulmão/fisiologia , Modelos Biológicos , Organoides/patologia , Organoides/fisiologia , Oxigênio/farmacologia , Oxigênio/fisiologia , Troca Gasosa Pulmonar/fisiologia , Mucosa Respiratória/citologia , Mucosa Respiratória/efeitos dos fármacos , Tecidos Suporte/química
3.
Artigo em Inglês | MEDLINE | ID: mdl-32244095

RESUMO

Symbiotic plant-microorganisms interaction is a promising approach to avoid the environmental hazards of synthetic fertilizers and pesticides. Among these, arbuscular mycorrhizal fungi (AMF) are known to improve the growth and quality of many plant species; however the detailed metabolic mechanisms behind such beneficial effects are far from complete. Further, elevated levels of atmospheric CO2 (eCO2) could affect such AMF-plant association. Herein, we have investigated the individual and synchronous impact of AMF and eCO2 (620 ppm) on nutrient uptake, growth, photosynthesis, respiration, and levels of primary and secondary metabolites in oregano (Oreganum vulgare), an economically important herbal plant. Enhanced AMF colonization rate and a better mycelial growth were observed in roots of oregano grown under eCO2. Both AMF and eCO2 treatments significantly enhanced the growth and photosynthesis of oregano plants, however much improvements were observed by their synchronous application. eCO2 further increased the AMF-induced dark respiration and accumulation of macro and microelements. Hierarchical clustering analysis of individual primary and secondary metabolites revealed a metabolite-dependent response toward AMF and eCO2. The synchronous application of AMF and eCO2 resulted in promoted accumulation of the majority of the detected sugars, organic acids, amino acids, unsaturated fatty acids, phenolic acids and flavonoids, as compared with the sole treatments. Moreover, AMF and eCO2 acted synergistically in improving the antioxidant capacity and anti-lipid peroxidation activity of oregano. Therefore, this study suggests that AMF treatment induces a global metabolic change in oregano, the effect that is strengthened under eCO2.


Assuntos
Micorrizas , Origanum , Dióxido de Carbono/farmacologia , Micorrizas/efeitos dos fármacos , Micorrizas/fisiologia , Origanum/efeitos dos fármacos , Origanum/microbiologia , Raízes de Plantas/microbiologia , Simbiose/efeitos dos fármacos
4.
Artigo em Inglês | MEDLINE | ID: mdl-32259674

RESUMO

Phenolic compounds, such as phytoalexin resveratrol, can be induced in grapes in response to biotic and abiotic stresses and have been related in many healthy effects. Stilbene synthases (STSs) are the key enzyme responsible for resveratrol biosynthesis. They have been already isolated and characterized from several plant species, however, VviSTS is a multigene family and little is known about their modulation in response to the application of gaseous treatments that maintain table grapes quality during postharvest. In this work, we have analyzed the effect of a 3-day CO2 treatment on the modulation of 4 STSs (VviSTS6, VviSTS7, VviSTS16 and VviSTS46) and on the accumulation of different stilbene compounds (resveratrol, resveratrol-glucoside, trans-piceatannol, z-miyabenol and pallidol) during the postharvest storage at 0 °C of white (Superior Seedless, Dominga), red (Red Globe) and black (Autumn Royal) table grapes. Results indicated that the accumulation of the stilbene compounds by the application of CO2 and low temperature storage were cultivar dependent. In white Dominga fruit, accumulation of stilbene compounds increased in CO2-treated samples what seems to be modulated by VviSTS6, VviSTS7 and VviSTS46. However, in Red Globe the accumulation of compounds was mainly due to the cold storage in air and seems to be also mediated by the induction of the same VviSTSs. By contrast, in Superior Seedless and Autumn Royal table grapes the modulation of VviSTSs genes and the stilbene accumulation was independent of the atmosphere storage. Further studies would be needed to elucidate the possible role of transcription factors involved on VviSTSs modulation.


Assuntos
Dióxido de Carbono , Temperatura Baixa , Regulação da Expressão Gênica , Estilbenos , Vitis , Dióxido de Carbono/farmacologia , Armazenamento de Alimentos , Frutas/efeitos dos fármacos , Frutas/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Estilbenos/metabolismo , Vitis/efeitos dos fármacos , Vitis/genética
5.
Food Chem ; 321: 126747, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32276147

RESUMO

The strawberry fruit is perishable due to its high water content and soft texture, yet exhibits pleasant organoleptic and nutritional profile. Here we conducted a metabolomics-driven analysis followed by linear modelling to dissect the molecular processes in strawberry postharvest. Fruits from five cultivars were harvested and refrigerated during a ten-day period under three different atmospheres: ambient, CO2-enriched and O3-enriched. These analyses revealed that metabolites involved in, (i) organoleptic and nutritional properties; (ii) stress tolerance displayed duration and postharvest treatment-dependent levels. Ozone-enriched atmosphere appears to counteract postharvest negative effects, with fruits exhibiting lower levels of fermentative metabolites when compared to fruits kept in an ambient atmosphere. Furthermore, metabolic reconfiguration towards the synthesis of protective metabolites of those fruits can possibly confer enhanced tolerance to postharvest abiotic stresses. Finally, results from the linear modelling identified metabolites which could be used as biomarkers to assess strawberry quality during its postharvest shelf life.


Assuntos
Armazenamento de Alimentos/métodos , Fragaria/metabolismo , Frutas/metabolismo , Biomarcadores/metabolismo , Dióxido de Carbono/farmacologia , Fragaria/química , Fragaria/efeitos dos fármacos , Frutas/química , Frutas/efeitos dos fármacos , Modelos Lineares , Ozônio/farmacologia , Estresse Fisiológico
6.
Parasit Vectors ; 13(1): 121, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32143711

RESUMO

BACKGROUND: Emerging arboviral diseases like Zika, dengue and chikungunya that are transmitted by Aedes aegypti mosquitoes, are increasingly threatening human health. Blends of human-like synthetic chemical attractants can be used to attract host-seeking mosquitoes. The aim of this study was to test new combinations of traps and odour baits in the laboratory, followed by testing the best candidates in the field to improve Ae. aegypti monitoring and surveillance. METHODS: First, the BG-Suna trap was evaluated for capturing laboratory-reared Ae. aegypti by testing normal and inverted positions in screen cage tests. Secondly, the attractiveness of the MB5 blend, CO2, and their combination was tested. Thirdly, we tested the attractiveness of different trap types (BG-Suna, BG-Sentinel, MM-X and CDC light trap). Finally, we confirmed laboratory results in the field in Paramaribo, Suriname, using the MB5 and BG-Lure odour blends, CO2 and the BG-Sentinel and BG-Bowl trap using a Latin Square design. RESULTS: The MB5 blend in combination with CO2 outperformed traps baited only with CO2 or MB5 in screen cage tests (P < 0.0001). The BG-Sentinel trap performed equally well as the inverted BG-Suna and was taken to the field (P = 0.729). In the field, we captured Ae. aegypti, Cx. quinquefasciatus and Cx. nigripalpus. We confirmed the laboratory results and found that the combination of the MB5 blend and CO2 almost doubled Ae. aegypti female captures (P = 0.004) and more than doubled Culex spp. female captures (P = 0.005) compared to using only CO2. Interestingly, the MB5 blend outperformed the commercially available BG-Lure, in the BG-Sentinel (P < 0.001). The BG-Bowl also attracted Ae. aegypti when baited with the MB5 blend in similar numbers as the BG-Sentinel baited with the MB5 (P = 0.362). CONCLUSIONS: Our study demonstrated that the BG-Sentinel trap baited with the MB5 blend and CO2 outperforms the current golden standard (BG-Sentinel trap with BG-Lure) for monitoring Ae. aegypti females and males, in both laboratory and field experiments. The BG-Bowl baited with the MB5 blend is a good candidate for home use. Finally, the results show that CO2 is an indispensable component of the attractive blend.


Assuntos
Comportamento Animal/fisiologia , Controle de Mosquitos/métodos , Mosquitos Vetores/fisiologia , Odorantes , Aedes/fisiologia , Animais , Dióxido de Carbono/farmacologia , Culex , Masculino , Controle de Mosquitos/instrumentação , Feromônios , Suriname
7.
Artigo em Inglês | MEDLINE | ID: mdl-32130026

RESUMO

Profound increases (>15 mmHg) in arterial carbon dioxide (i.e., hypercapnia) reduce renal blood flow. However, a relatively brief and mild hypercapnia can occur in patients with sleep apnea or in those receiving supplemental oxygen therapy during an acute exacerbation of chronic obstructive pulmonary disease. We tested the hypothesis that a brief, mild hypercapnic exposure increases vascular resistance in the renal and segmental arteries. Blood velocity in 14 healthy adults (26 ± 4 yr; 7 women, 7 men) was measured in the renal and segmental arteries with Doppler ultrasound while subjects breathed room air (Air) and while they breathed a 3% CO2, 21% O2, 76% N2 gas mixture for 5 min (CO2). The end-tidal partial pressure of CO2 ([Formula: see text]) was measured via capnography. Mean arterial pressure (MAP) was measured beat to beat via the Penaz method. Vascular resistance in the renal and segmental arteries was calculated as MAP divided by blood velocity. [Formula: see text] increased with CO2 (Air: 45 ± 3, CO2: 48 ± 3 mmHg, P < 0.01), but there were no changes in MAP (P = 0.77). CO2 decreased blood velocity in the renal (Air: 35.2 ± 8.1, CO2: 32.2 ± 7.3 cm/s, P < 0.01) and segmental (Air: 24.2 ± 5.1, CO2: 21.8 ± 4.2 cm/s, P < 0.01) arteries and increased vascular resistance in the renal (Air: 2.7 ± 0.9, CO2: 3.0 ± 0.9 mmHg·cm-1·s, P < 0.01) and segmental (Air: 3.9 ± 1.0, CO2: 4.4 ± 1.0 mmHg·cm-1·s, P < 0.01) arteries. These data provide evidence that the kidneys are hemodynamically responsive to a mild and acute hypercapnic stimulus in healthy humans.


Assuntos
Dióxido de Carbono/farmacologia , Hemodinâmica/efeitos dos fármacos , Hipercapnia/fisiopatologia , Rim/irrigação sanguínea , Resistência Vascular/efeitos dos fármacos , Adulto , Artérias/efeitos dos fármacos , Feminino , Humanos , Masculino , Adulto Jovem
8.
Food Chem ; 318: 126462, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32126463

RESUMO

Degreening is widely used in citrus fruit to extend the market season for economic gains and increase the consumer acceptance. Elevated CO2 was exogenously applied to Satsuma mandarins (Citrus unshiu Marc.) for degreening and its effect on pigment metabolism was investigated. The results revealed 15% CO2 treatment accelerated the citrus fruit peel color change along with the chlorophyll degradation, ß-cryptoxanthin and flavonoids accumulation. The expression of CitSGR, CitNYC, CitChlase, CitPPH, CitPAO and CitRCCR genes involved in chlorophyll metabolism and a set of genes involved in producing ß, ß-xanthophylls were up-regulated by elevated CO2. For flavonoid metabolism, the up-regulated expressions of CitPAL, CitCHS and CitCHI partly explained the increased total flavonoids content. These results showed that 15% CO2 treatment improved the visual appearance of citrus fruits due to its impact on pigment metabolism and also maintained their nutritional value, thus could be employed as a potential commercial technique for citrus degreening.


Assuntos
Dióxido de Carbono/farmacologia , Citrus/fisiologia , Armazenamento de Alimentos/métodos , Pigmentação/efeitos dos fármacos , Pigmentos Biológicos/metabolismo , Adulto , Clorofila/genética , Clorofila/metabolismo , Citrus/química , Citrus/efeitos dos fármacos , Feminino , Flavonoides/genética , Flavonoides/metabolismo , Frutas/química , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Humanos , Masculino , Pigmentação/fisiologia , Pigmentos Biológicos/genética , Paladar , Xantofilas/análise , Xantofilas/metabolismo
9.
PLoS One ; 15(3): e0223937, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32168346

RESUMO

Panicum maximum Jacq. 'Mombaça' (Guinea grass) is a C4 forage grass widely used in tropical pastures for cattle feeding. In this study, we evaluated the isolated and combined effects of warming and elevated CO2 concentration [CO2] during summer on nutrient content, nutrient accumulation, nutrient use efficiency and growth of P. maximum under field conditions. Field temperature and [CO2] were controlled by temperature free-air controlled enhancement and free-air CO2 enrichment systems, respectively. We tested two levels of canopy temperature: ambient temperature (aT) and 2°C above ambient temperature (eT), as well as two levels of atmospheric [CO2]: ambient [CO2] (aCO2) and 200 ppm above ambient CO2 (eCO2). The experiment was established in a completely randomized design with four replications, in a 2×2 factorial scheme. After pasture establishment, plants were exposed to the treatments during 30 days, with evaluations at 9, 16, 23 and 30 days after the treatments started. Results were dependent on the time of the evaluation, but in the last evaluation (beginning of the grazing), contents of N, K, Mg and S did not change as a function of treatments. However, P decreased as a function of warming under both levels of [CO2], and Ca increased under [eCO2] combined with warming. There was an increase in root dry mass under warming treatment. Combined treatment increased N, Ca and S accumulation without a corresponding increase in the use efficiency of these same nutrients, indicating that the fertiliser dose should increase in the next decades due to climate change. Our short-term results in young and well fertilized pasture suggest that under the combination of [eCO2] and eT conditions, P. maximum productivity will increase and the nutritional requirement for N, Ca and S will also increase.


Assuntos
Dióxido de Carbono/farmacologia , Temperatura Alta , Nutrientes/análise , Panicum/crescimento & desenvolvimento , Ração Animal , Animais , Cálcio/análise , Dióxido de Carbono/química , Bovinos , Mudança Climática , Nitrogênio/análise , Concentração Osmolar , Panicum/efeitos dos fármacos , Solo/química , Água
10.
Artigo em Inglês | MEDLINE | ID: mdl-32078898

RESUMO

Rising atmospheric CO2 concentrations ([CO2]) together with water deficit can influence ecological interactions of trees through an array of chemically driven changes in plant leaves. In four drought stressed Pinus pinaster genotypes, grown under two levels of atmospheric [CO2] (ambient (aCO2) and enriched (eCO2)) the metabolome of adult and juvenile needles was analyzed to know if the metabolic responses to this environmental situation could be genotype-dependent and vary according to the stage of needle ontogeny. Drought had the highest incidence, followed by needle ontogeny, being lower the eCO2 effect. The eCO2 reduced, eliminated or countered the 50 (adult needles) - 44% (juvenile) of the drought-induced changes, suggesting that CO2-enriched plants could perceived less oxidative stress under drought, and proving that together, these two abiotic factors triggered a metabolic response different from that under single factors. Genotype drought tolerance and ontogenetic stage determined the level of metabolite accumulation and the plasticity to eCO2 under drought, which was mainly reflected in antioxidant levels and tree chemical defense. At re-watering, previously water stressed plants showed both, reduced C and N metabolism, and a "drought memory effect", favoring antioxidants and osmolyte storage. This effect showed variations regarding genotype drought-tolerance, needle ontogeny and [CO2], with remarkable contribution of terpenoids. Chemical defense and drought tolerance were somehow linked, increasing chemical defense during recovery in the most drought-sensitive individuals. The better adaptation of trees to drought under eCO2, as well as their ability to recover better from water stress, are essential for the survival of forest trees.


Assuntos
Dióxido de Carbono , Secas , Metaboloma , Pinus , Folhas de Planta , Dióxido de Carbono/farmacologia , Genótipo , Metaboloma/efeitos dos fármacos , Pinus/efeitos dos fármacos , Pinus/genética , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/metabolismo , Água
11.
Int J Food Microbiol ; 321: 108550, 2020 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-32058874

RESUMO

Low water activity (aW) foods permit the survival of low-infectious dose pathogens including Escherichia coli and Salmonella. Desiccation of non-heat resistant E. coli and Salmonella enterica increases their heat resistance; therefore, alternative methods are necessary to ensure the safety of low aW foods. High-pressure carbon dioxide (HPCD) reduced microbial contaminants in high aW foods. This study aimed to identify HPCD conditions that reduce pathogenic E. coli and Salmonella in low aW conditions. Four strains of Shiga toxin-producing E. coli (STEC) and one strain of enteropathogenic E. coli were treated as a cocktail, and five strains of Salmonella were treated individually. The suitability of E. coli AW1.7, Pediococcus acidilactici FUA 3072, Enterococcus faecium NRRL B-2354 and Staphylococcus carnosus R6 FUA 2133 as surrogate organisms was evaluated. Treatments were validated in beef jerky. Samples were equilibrated to aW 0.75 and treated with heat, HPCD or pressurized N2. Treatment of desiccated E. coli AW1.7 and the STEC cocktail with dry gaseous CO2 (5.7 MPa and 65 °C) did not reduce cell counts; however, treatment with gaseous CO2 saturated with water reduced cell counts of all strains of E. coli. Treatment of beef jerky inoculated with E. coli and Salmonella with saturated gaseous CO2 resulted in >5-log reductions for all strains. E. faecium NRRL B-2354 and S. carnosus R6 were suitable surrogates for Salmonella on beef jerky treated with HPCD. Treatment of beef jerky with water-saturated gaseous CO2 was more effective than treatment with supercritical CO2 or treatments with N2 at the same temperature and pressure. Overall, the treatment of low aW foods with water-saturated gaseous HPCD can meet industry standards by achieving a >5-log reductions of E. coli and Salmonella. Additionally, surrogate organisms representing pathogenic E. coli and Salmonella have been validated.


Assuntos
Dióxido de Carbono/farmacologia , Alimentos em Conserva/microbiologia , Carne Vermelha/microbiologia , Salmonella/efeitos dos fármacos , Escherichia coli Shiga Toxigênica/efeitos dos fármacos , Animais , Bovinos , Microbiologia de Alimentos , Alimentos em Conserva/análise , Pasteurização/métodos , Água/análise
12.
Planta ; 251(2): 52, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31950281

RESUMO

MAIN CONCLUSION: Our study demonstrated that the species respond non-linearly to increases in CO2 concentration when exposed to decadal changes in CO2, representing the year 1987, 2025, 2051, and 2070, respectively. There are several lines of evidence suggesting that the vast majority of C3 plants respond to elevated atmospheric CO2 by decreasing their stomatal conductance (gs). However, in the majority of CO2 enrichment studies, the response to elevated CO2 are tested between plants grown under ambient (380-420 ppm) and high (538-680 ppm) CO2 concentrations and measured usually at single time points in a diurnal cycle. We investigated gs responses to simulated decadal increments in CO2 predicted over the next 4 decades and tested how measurements of gs may differ when two alternative sampling methods are employed (infrared gas analyzer [IRGA] vs. leaf porometer). We exposed Populus tremula, Popolus tremuloides and Sambucus racemosa to four different CO2 concentrations over 126 days in experimental growth chambers at 350, 420, 490 and 560 ppm CO2; representing the years 1987, 2025, 2051, and 2070, respectively (RCP4.5 scenario). Our study demonstrated that the species respond non-linearly to increases in CO2 concentration when exposed to decadal changes in CO2. Under natural conditions, maximum operational gs is often reached in the late morning to early afternoon, with a mid-day depression around noon. However, we showed that the daily maximum gs can, in some species, shift later into the day when plants are exposed to only small increases (70 ppm) in CO2. A non-linear decreases in gs and a shifting diurnal stomatal behavior under elevated CO2, could affect the long-term daily water and carbon budget of many plants in the future, and therefore alter soil-plant-atmospheric processes.


Assuntos
Atmosfera/química , Dióxido de Carbono/farmacologia , Fisiologia/métodos , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/fisiologia , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/efeitos da radiação , Raios Infravermelhos , Luz , Estômatos de Plantas/efeitos da radiação , Análise de Regressão
13.
Artigo em Inglês | MEDLINE | ID: mdl-31967860

RESUMO

Naked mole-rats (NMRs) live in large colonies within densely populated underground burrows. Their collective respiration generates significant metabolic carbon dioxide (CO2) that diffuses slowly out of the burrow network, creating a hypercapnic environment. Currently, the physiological mechanisms that underlie the ability of NMRs to tolerate environmental hypercapnia are largely unknown. To address this, we used whole-body plethysmography and respirometry to elucidate the hypercapnic ventilatory and metabolic responses of awake, freely behaving NMRs to 0%-10% CO2. We found that NMRs have a blunted hypercapnic ventilatory response (HCVR): ventilation increased only in 10% CO2. Conversely, metabolism was unaffected by hypercapnia. NMRs are insensitive to cutaneous acid-based pain caused by modified substance P (SP)-mediated peripheral neurotransmission, and SP is also an important neuromodulator of ventilation. Therefore, we re-evaluated physiological responses to hypercapnia in NMRs after an intraperitoneal injection of exogenous substance P (2 mg/kg) or a long-lived isoform of substance P {[pGlu5-MePhe8-MeGly9]SP(5-11), DiMe-C7; 40-400 µg/kg}. We found that both drugs restored hypercapnia sensitivity and unmasked an HCVR in animals breathing 2%-10% CO2. Taken together, our findings indicate that NMRs are remarkably tolerant of hypercapnic environments and have a blunted HCVR; however, the signaling network architecture required for a "normal" HCVR is retained but endogenously inactive. This muting of chemosensitivity likely suits the ecophysiology of this species, which presumably experiences hypercapnia regularly in their underground niche.


Assuntos
Dióxido de Carbono/farmacologia , Hipercapnia , Ratos-Toupeira , Receptores da Neurocinina-1/metabolismo , Fenômenos Fisiológicos Respiratórios , Substância P/metabolismo , Animais , Dióxido de Carbono/administração & dosagem , Masculino , Pletismografia , Substância P/deficiência
14.
Aquat Toxicol ; 220: 105400, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31901577

RESUMO

We investigated the impacts of carbon dioxide (CO2)-induced acidification on energy metabolism in muscle tissue of rainbow trout Oncorhynchus mykiss fry. Fry were exposed to freshwater in equilibrium with air containing CO2 at volume concentrations of 380, 1000 and 2000 ppm for 30 days. At this critical and sensitive life stage, we showed dose-dependent reductions in weight gain and changes in energy metabolism under projected future CO2 levels. Rainbow trout fry exposed to elevated CO2 concentrations produced more energy in muscle tissue because ATP levels were significantly elevated. Fry exposed to 1000 ppm CO2 had a higher activity of pyruvate kinase (PK), higher concentrations of pyruvate, acetate, 2-oxoglutarate, phenylalanine, tyrosine, inosine, uracil and uridine, and lower concentrations of anserine and IMP in muscle tissue based on metabolomic analysis. We infer that the increased ATP production in fry exposed to 1000 ppm CO2 is produced through glycolysis. In the 2000 ppm group, the protein content of muscle was lower than in the control, and the activities of PK, cytochrome C oxidase (COX), Na+/K+-ATP and Ca2+/Mg2+-ATPase were significantly higher. Concentrations of pyruvate, 2-oxoglutarate, histidine, anserine and IMP were significantly lower, and alanine, methionine, leucine, isoleucine, valine, lysine, pantothenate, uracil and inosine were significantly higher. Accelerated tissue decomposition may have sustained the higher production of ATP in the 2000 ppm group.


Assuntos
Dióxido de Carbono/farmacologia , Metabolismo Energético/efeitos dos fármacos , Músculos/metabolismo , Oncorhynchus mykiss/metabolismo , Animais , Metabolômica , Oncorhynchus mykiss/crescimento & desenvolvimento , Poluentes Químicos da Água/toxicidade
15.
Food Chem ; 312: 126114, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31901819

RESUMO

Preserving quality of crustaceans requires efficient modified atmosphere packaging (MAP). Effects of CO2 (20%-80%) on quality and melanosis in chilled Pacific white shrimp (Litopenaeus vannamei) under O2 concentrations of 5 and 15% were investigated. Increased headspace CO2 and lipid oxidation contributed to loss of firmness due to protein degradation. Image analysis indicated increased degree of melanosis at higher O2 concentration. High CO2 above 60% and 5% O2 MAP effectively prevented melanosis (below 10% for 12 days) and formation of trimethylamine (TMA) concurrent with limited total viable count (TVC), Enterobacteriaceae and reduced conversion of pro-polyphenoloxidase into polyphenoloxidase accelerated shell browning. Linear correlation was found between TVC-melanosis and TVC-firmness for all MAP mixtures, while CO2 gave higher efficacy to inhibit melanosis at low O2 MAP. Increased CO2 linearly prevented melanosis and TMA formation, whereas decreased O2 concentration gave higher efficacy of CO2 indicated synergistic effects on melanosis and TMA inhibition.


Assuntos
Dióxido de Carbono/farmacologia , Penaeidae/metabolismo , Animais , Atmosfera , Catecol Oxidase/metabolismo , Microbiologia de Alimentos
16.
Can J Microbiol ; 66(4): 263-273, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31999470

RESUMO

Trace gas uptake by microorganisms controls the oxidative capacity of the troposphere, but little is known about how this important function is affected by changes in soil microbial diversity. This article bridges that knowledge gap by examining the response of the microbial community-level physiological profiles (CLPPs), carbon dioxide (CO2) production, and molecular hydrogen (H2) and carbon monoxide (CO) oxidation activities to manipulation of microbial diversity in soil microcosms. Microbial diversity was manipulated by mixing nonsterile and sterile soil with and without the addition of antibiotics. Nonsterile soil without antibiotics was used as a reference. Species composition changed significantly in soil microcosms as a result of dilution and antibiotic treatments, but there was no difference in species richness, according to PCR amplicon sequencing of the bacterial 16S rRNA gene. The CLPP was 15% higher in all dilution and antibiotic treatments than in reference microcosms, but the dilution treatment had no effect on CO2 production. Soil microcosms with dilution treatments had 58%-98% less H2 oxidation and 54%-99% lower CO oxidation, relative to reference microcosms, but did not differ among the antibiotic treatments. These results indicate that H2 and CO oxidation activities respond to compositional changes of microbial community in soil.


Assuntos
Bactérias/efeitos dos fármacos , Monóxido de Carbono/química , Hidrogênio/química , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Dióxido de Carbono/química , Dióxido de Carbono/farmacologia , Monóxido de Carbono/farmacologia , Hidrogênio/farmacologia , Microbiota , Oxirredução , Solo/química
17.
Physiol Plant ; 168(3): 694-708, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31376304

RESUMO

Carbon dioxide concentration (CO2 ) and light intensity are known to play important roles in plant growth and carbon assimilation. Nevertheless, the underlying physiological mechanisms have not yet been fully explored. Tomato seedlings (Solanum lycopersicum Mill. cv. Jingpeng No. 1) were exposed to two levels of CO2 and three levels of light intensity and the effects on growth, leaf gas exchange and water use efficiency were investigated. Elevated CO2 and increased light intensity promoted growth, dry matter accumulation and pigment concentration and together the seedling health index. Elevated CO2 had no significant effect on leaf nitrogen content but did significantly upregulate Calvin cycle enzyme activity. Increased CO2 and light intensity promoted photosynthesis, both on a leaf-area basis and on a chlorophyll basis. Increased CO2 also increased light-saturated maximum photosynthetic rate, apparent quantum efficiency and carboxylation efficiency and, together with increased light intensity, it raised photosynthetic capacity. However, increased CO2 reduced transpiration and water consumption across different levels of light intensity, thus significantly increasing both leaf-level and plant-level water use efficiency. Among the range of treatments imposed, the combination of increased CO2 (800 µmol CO2 mol-1 ) and high light intensity (400 µmol m-2 s-1 ) resulted in optimal growth and carbon assimilation. We conclude that the combination of increased CO2 and increased light intensity worked synergistically to promote growth, photosynthetic capacity and water use efficiency by upregulation of pigment concentration, Calvin cycle enzyme activity, light energy use and CO2 fixation. Increased CO2 also lowered transpiration and hence water usage.


Assuntos
Dióxido de Carbono/farmacologia , Luz , Lycopersicon esculentum/fisiologia , Fotossíntese , Clorofila/fisiologia , Lycopersicon esculentum/efeitos da radiação , Folhas de Planta/fisiologia , Transpiração Vegetal , Plântula
18.
Neuron ; 105(1): 106-121.e10, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31757604

RESUMO

The extent to which behavior is shaped by experience varies between individuals. Genetic differences contribute to this variation, but the neural mechanisms are not understood. Here, we dissect natural variation in the behavioral flexibility of two Caenorhabditis elegans wild strains. In one strain, a memory of exposure to 21% O2 suppresses CO2-evoked locomotory arousal; in the other, CO2 evokes arousal regardless of previous O2 experience. We map that variation to a polymorphic dendritic scaffold protein, ARCP-1, expressed in sensory neurons. ARCP-1 binds the Ca2+-dependent phosphodiesterase PDE-1 and co-localizes PDE-1 with molecular sensors for CO2 at dendritic ends. Reducing ARCP-1 or PDE-1 activity promotes CO2 escape by altering neuropeptide expression in the BAG CO2 sensors. Variation in ARCP-1 alters behavioral plasticity in multiple paradigms. Our findings are reminiscent of genetic accommodation, an evolutionary process by which phenotypic flexibility in response to environmental variation is reset by genetic change.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Dendritos/metabolismo , Plasticidade Neuronal/fisiologia , Neuropeptídeos/biossíntese , Transdução de Sinais/fisiologia , Animais , Animais Geneticamente Modificados , Nível de Alerta/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Dióxido de Carbono/farmacologia , Feminino , Individualidade , Diester Fosfórico Hidrolases/metabolismo , Polimorfismo Genético , Células Receptoras Sensoriais/metabolismo , Especificidade da Espécie
19.
Chemosphere ; 243: 125415, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31770697

RESUMO

Oceanic uptake of atmospheric CO2 is reducing seawater pH and shifting carbonate chemistry within, a process termed as ocean acidification (OA). Marine mussels are a family of ecologically and economically significant bivalves that are widely distributed along coastal areas worldwide. Studies have demonstrated that OA greatly disrupts mussels' physiological functions. However, the underlying molecular responses (e.g., whether there were any molecular compensation mechanisms) and the extent to which OA affects mussel shell defense capacity remain largely unknown. In this study, the thick shell mussels Mytilus coruscus were exposed to the ambient pH (8.1) or one of two lowered pH levels (7.8 and 7.4) for 40 days. The results suggest that future OA will damage shell structure and weaken shell strength and shell closure strength, ultimately reducing mussel shell defense capacity. In addition, future OA will also disrupt haemolymph pH and Ca2+ homeostasis, leading to extracellular acidosis and Ca2+ deficiency. Mantle transcriptome analyses indicate that mussels will adopt a series of molecular compensatory responses to mitigate these adverse effects; nevertheless, weakened shell defense capacity will increase mussels' susceptibility to predators, parasites and pathogens, and thereby reduce their fitness. Overall, the findings of this study have significant ecological and economic implications, and will enhance our understanding of the future of the mussel aquaculture industry and coastal ecosystems.


Assuntos
Dióxido de Carbono/farmacologia , Concentração de Íons de Hidrogênio , Mytilus/fisiologia , Água do Mar/química , Animais , Dióxido de Carbono/química , Ecossistema , Homeostase , Oceanos e Mares
20.
Physiol Plant ; 168(1): 218-226, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31069813

RESUMO

The metabolic basis for observed differences in the yield response of rice to projected carbon dioxide concentrations (CO2 ) is unclear. In this study, three rice cultivars, differing in their yield response to elevated CO2 , were grown under ambient and elevated CO2 conditions, using the free-air CO2 enrichment technology. Flag leaves of rice were used to determine (1) if manipulative increases in sink strength decreased the soluble sucrose concentration for the 'weak' responders and (2), whether the genetic expression of sucrose transporters OsSUT1 and OsSUT2 was associated with an accumulation of soluble sugars and the maintenance of photosynthetic capacity. For the cultivars that showed a weak response to additional CO2 , photosynthetic capacity declined under elevated CO2 and was associated with an accumulation of soluble sugars. For these cultivars, increasing sink relative to source strength did not increase photosynthesis and no change in OsSUT1 or OsSUT2 expression was observed. In contrast, the 'strong' response cultivar did not show an increase in soluble sugars or a decline in photosynthesis but demonstrated significant increases in OsSUT1 and OsSUT2 expression at elevated CO2 . Overall, these data suggest that the expression of the sucrose transport genes OsSUT1 and OsSUT2 may be associated with the maintenance of photosynthetic capacity of the flag leaf during grain fill; and, potentially, greater yield response of rice as atmospheric CO2 increases.


Assuntos
Dióxido de Carbono/farmacologia , Oryza/genética , Fotossíntese , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Oryza/fisiologia , Folhas de Planta , Sacarose
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