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1.
Molecules ; 26(7)2021 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-33808054

RESUMEN

The main protease (Mpro) is a major protease having an important role in viral replication of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel coronavirus that caused the pandemic of 2020. Here, active Mpro was obtained as a 34.5 kDa protein by overexpression in E. coli BL21 (DE3). The optimal pH and temperature of Mpro were 7.5 and 37 °C, respectively. Mpro displayed a Km value of 16 µM with Dabcyl-KTSAVLQ↓SGFRKME-Edans. Black garlic extract and 49 polyphenols were studied for their inhibitory effects on purified Mpro. The IC50 values were 137 µg/mL for black garlic extract and 9-197 µM for 15 polyphenols. The mixtures of tannic acid with puerarin, daidzein, and/or myricetin enhanced the inhibitory effects on Mpro. The structure-activity relationship of these polyphenols revealed that the hydroxyl group in C3', C4', C5' in the B-ring, C3 in the C-ring, C7 in A-ring, the double bond between C2 and C3 in the C-ring, and glycosylation at C8 in the A-ring contributed to inhibitory effects of flavonoids on Mpro.


Asunto(s)
/antagonistas & inhibidores , Polifenoles/química , Polifenoles/farmacología , Inhibidores de Proteasas/farmacología , /genética , Dimetilsulfóxido/farmacología , Sinergismo Farmacológico , Ajo/química , Concentración de Iones de Hidrógeno , Extractos Vegetales/farmacología , Plantas/química , Inhibidores de Proteasas/química , Relación Estructura-Actividad , Temperatura
2.
An Acad Bras Cienc ; 93(1): e20190672, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33825790

RESUMEN

Lipases are hydrolases used in various sectors such as the food, pharmaceutical and chemical synthesis industries. In this study, epiphytic microorganisms were isolated from the Serra of Ouro Branco State Park (Minas Gerais, Brazil) and were subsequently evaluated for their ability to produce extracellular lipases. Among the 46 isolated strains, 25 presented positive results for lipase production in the agar plate screening assay. Two of these strains that expressed the highest diffusion halos, were genetically identified as Serratia marcescens and Pseudomonas fluorescens and catalogued in the Tropical Cultures Collection from the André Tosello Foundation/Brazil as CCT 7796 and CCT 7797, respectively. The fermentation growth kinetics indicated that the maximum extracellular lipase activities were achieved between 96 and 120h of cultivation. The highest lipolytic activity for both strains was observed at an optimum temperature and pH of 37°C and 7.0, respectively. At these conditions, the lipase activity detected in the crude enzymatic extract of both strains was close to 15.0 U/mL. We consider that these species are promising lipase producers for industrial applications.


Asunto(s)
Lipasa , Lipólisis , Brasil , Fermentación , Concentración de Iones de Hidrógeno , Cinética , Temperatura
3.
Environ Monit Assess ; 193(5): 253, 2021 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-33834313

RESUMEN

Pine tree (Pinus pinea) components have been used as passive air samples for determining atmospheric polycyclic aromatic hydrocarbon (PAH) concentrations. Our results indicated that pine needles and branches were found to be statistically successful in describing the ambient air. Monthly pine needles, branches (1- and 2-year-old) and ambient air samples were collected for 1 year to identify molecular distributions and temporal concentrations of PAHs in a suburban-industrial area. Annual average Σ14PAH concentrations for pine needles, 1- and 2-year-old branches, and ambient air were 756 ± 232 ng/g DW, 685 ± 350 ng/g DW, 587 ± 361 ng/g DW, and 28.29 ± 32.33 ng/m3, respectively. The order of average Σ14PAH concentrations in the pine tree components was determined as needle > 1-year-old branch > 2-year-old branch. In general, concentrations increased with the rise in the surface area of tree components. In the samples, 3- and 4-ring PAHs were dominant compounds in the ambient air, pine needles, and branches. The annual total fraction of 3- and 4-ring PAHs in the air was 98.5%, while the fraction of 5- and 6-ring PAHs was 1.5%. On the other hand, 3- and 4-ring PAHs in pine needles and branches were 30% or more. The fraction and level of PAHs change with the season. Although needle samples did not show any seasonal trend, PAH levels in other tree components changed with the air temperature. Generally, lower values were observed in warmer seasons in the branch samples. Similarly, ambient air PAH concentrations were higher in the winter season due to heating and adverse meteorological conditions.


Asunto(s)
Contaminantes Atmosféricos , Pinus , Hidrocarburos Policíclicos Aromáticos , Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente , Hidrocarburos Policíclicos Aromáticos/análisis , Estaciones del Año , Temperatura
4.
Zhongguo Yi Liao Qi Xie Za Zhi ; 45(2): 119-124, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33825367

RESUMEN

Effects of heat treatment conditions (including temperature and time) on the shape memory recovery and corrosion resistance of NiTi self-expanding vascular stents were studied based on working mechanism and clinical use. The Af temperature, dimensional recovery, crush resistance with radially applied load and point applied load of stents and corrosion resistance were characterized in diffident heat treatment conditions. The research results allow the conclusion that the stent treated at 500 ℃ for 10 min has optimum performance, and corrosion resistance meets the requirements.


Asunto(s)
Aleaciones , Calor , Corrosión , Ensayo de Materiales , Stents , Propiedades de Superficie , Temperatura , Titanio
5.
Pestic Biochem Physiol ; 174: 104826, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33838719

RESUMEN

Liriomyza trifolii is an invasive leafminer fly that inflicts damage on many horticultural and vegetable crops. In this study, the effects of elevated temperatures on L. trifolii tolerance to insecticides abamectin (AB), monosultap (MO) and a mixture of abamectin and monosultap (AM) were firstly investigated, then five CYP450 genes (LtCYPs) were cloned, and expression patterns and NADPH cytochrome C reductase (NCR) activity in L. trifolii were compared in response to high temperature stress and insecticide exposure. Results showed elevated temperatures induced expression of LtCYP450s, the expression level of LtCYP4g1, LtCYP4g15 and LtCYP301A1 after exposed to different high temperature were significantly up-regulated compared with the control (25 °C), while there was no significant difference in LtCYP4E21 and LtCYP18A1. Under the joint high temperature and insecticide stress, the expression of LtCYP4g15, LtCYP18A1 and LtCYP301A1 was significantly higher under elevated temperatures than that of only under AB exposure. For MO and AM exposure, only 40 °C could induce the expression of LtCYP4g15, LtCYP18A1 and LtCYP301A1. In general, the LtCYPs expression pattern was correlated with increased NCR activity and decreased mortality in response to insecticide exposure under elevated temperatures. These all demonstrated that insecticide tolerance in L. trifolii could be mediated by high temperature. This study improves our understanding of L. trifolii physiology and offers a theoretical context for improved control that ultimately reduces the abuse of insecticides and decreases exposure to non-target organisms.


Asunto(s)
Dípteros , Insecticidas , Animales , Productos Agrícolas , Sistema Enzimático del Citocromo P-450/genética , Insecticidas/toxicidad , Temperatura
6.
Food Chem ; 351: 129273, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33662907

RESUMEN

Heat processing of ready-to-drink beverages is required to ensure a microbiologically safe product, however, this can result in the loss of bioactive compounds responsible for functionality. The objective of this study was to establish the thermal stability of a novel dihydrochalcone, 3',5'-di-ß-d-glucopyranosyl-3-hydroxyphloretin (2), 3',5'-di-ß-d-glucopyranosylphloretin (3) and other Cyclopia subternata phenolic compounds, in model solutions with or without citric acid and ascorbic acid. The solutions were heated at 93, 121 and 135 °C, relevant to pasteurisation, commercial sterilisation and ultra-high temperature (UHT) pasteurisation, respectively. For most compounds, the acids decreased the second order reaction rate constants, up to 27 times. Compound 2 (46.29 ± 0.53 (g/100 g)-1 h-1), and to a lesser extent compound 3 (5.94 ± 0.01 (g/100 g)-1 h-1) were the most thermo-unstable compounds when treated at 135 °C without added acids. Even though differential effects were observed for compounds at different temperatures and formulations, overall, the phenolic compounds were most stable under UHT pasteurisation conditions.


Asunto(s)
Bebidas/análisis , Chalconas/química , Fabaceae/química , Extractos Vegetales/química , Polifenoles/química , Temperatura , Glicosilación , Pasteurización , Fenoles/análisis , Soluciones
7.
Food Chem ; 351: 129335, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33662910

RESUMEN

The effect of hydrolysis degree of gallotannins (GT, 1 mg/g) on cross-linking of nano-size collagen catalyzed by laccase (12 U/g) was studied, and the antibacterial properties of GT hydrolysates (HGT)-laccase (Lac) collagen films on minced cod were also investigated. The results showed that the tensile strength of HGT-Lac films (87.23-100.77 MPa) was higher than those added HGT alone (85.59-95.58 MPa) under the same hydrolysis degree of GT. Compared to the denaturation temperature (78.05 °C) of pure nano-size collagen film without addition of HGT and laccase, the denaturation temperature of HGT (80.75-86.30 °C) and HGT-Lac (91.97-101.64 °C) films increased greatly, especially for HGT-Lac films. Moreover, both HGT and HGT-Lac films showed some mild antibacterial properties for minced cod during storage at 4 °C for 8 days. Therefore, the combination of HGT and laccase could improve the performance of nano-size collagen film and extend the application of collagen in biodegradable/edible packaging.


Asunto(s)
Biocatálisis , Colágeno/química , Colágeno/metabolismo , Taninos Hidrolizables/química , Lacasa/metabolismo , Películas Comestibles , Temperatura , Resistencia a la Tracción
8.
PLoS Negl Trop Dis ; 15(3): e0009259, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33705409

RESUMEN

Dengue, Zika and chikungunya are diseases of global health significance caused by arboviruses and transmitted by the mosquito Aedes aegypti, which is of worldwide circulation. The arrival of the Zika and chikungunya viruses to South America increased the complexity of transmission and morbidity caused by these viruses co-circulating in the same vector mosquito species. Here we present an integrated analysis of the reported arbovirus cases between 2007 and 2017 and local climate and socio-economic profiles of three distinct Colombian municipalities (Bello, Cúcuta and Moniquirá). These locations were confirmed as three different ecosystems given their contrasted geographic, climatic and socio-economic profiles. Correlational analyses were conducted with both generalised linear models and generalised additive models for the geographical data. Average temperature, minimum temperature and wind speed were strongly correlated with disease incidence. The transmission of Zika during the 2016 epidemic appeared to decrease circulation of dengue in Cúcuta, an area of sustained high incidence of dengue. Socio-economic factors such as barriers to health and childhood services, inadequate sanitation and poor water supply suggested an unfavourable impact on the transmission of dengue, Zika and chikungunya in all three ecosystems. Socio-demographic influencers were also discussed including the influx of people to Cúcuta, fleeing political and economic instability from neighbouring Venezuela. Aedes aegypti is expanding its range and increasing the global threat of these diseases. It is therefore vital that we learn from the epidemiology of these arboviruses and translate it into an actionable local knowledge base. This is even more acute given the recent historical high of dengue cases in the Americas in 2019, preceding the COVID-19 pandemic, which is itself hampering mosquito control efforts.


Asunto(s)
Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Infección por el Virus Zika/epidemiología , Aedes/fisiología , Aedes/virología , Animales , Fiebre Chikungunya/economía , Fiebre Chikungunya/virología , Virus Chikungunya/fisiología , Clima , Colombia/epidemiología , Dengue/economía , Dengue/virología , Virus del Dengue/fisiología , Ecosistema , Humanos , Mosquitos Vectores/fisiología , Mosquitos Vectores/virología , América del Sur , Temperatura , Virus Zika/fisiología , Infección por el Virus Zika/economía , Infección por el Virus Zika/virología
9.
Int J Nanomedicine ; 16: 1977-1992, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33727810

RESUMEN

Background: Phytostanols are naturally occurring compounds that reduce blood cholesterol levels significantly. However, their aqueous insolubility poses formulation challenges. Aim: To formulate and characterize solid lipid nanoparticle carriers for phytostanol esters to enhance the bioavailability of phytostanols. Methods: Phytostanol ester solid lipid nanoparticles were formulated by the microemulsion method. They were characterized for particle size distribution, polydispersity index, shape, surface charge, entrapment efficiency, stability, chemical structure, and thermal properties. The uptake of the formulation by cell lines, HepG2 and HT-29, and its effect on cell viability were evaluated. Results: The formulation of solid lipid nanoparticles was successfully optimised by varying the type of lipids and their concentration relative to that of surfactants in the present study. The optimised formulation had an average diameter of (171 ± 9) nm, a negative surface charge of (-23.0 ± 0.8) mV and was generally spherical in shape. We report high levels of drug entrapment at (89 ± 5)% in amorphous form, drug loading of (9.1 ± 0.5)%, nanoparticle yield of (67 ± 4)% and drug excipient compatibility. The biological safety and uptake of the formulations were demonstrated on hepatic and intestinal cell lines. Conclusion: Phytostanol ester solid lipid nanoparticles were successfully formulated and characterized. The formulation has the potential to provide an innovative drug delivery system for phytostanols which reduce cholesterol and have a potentially ideal safety profile. This can contribute to better management of one of the main risk factors of cardiovascular diseases.


Asunto(s)
Composición de Medicamentos , Ésteres/química , Hipercolesterolemia/tratamiento farmacológico , Lípidos/química , Nanopartículas/química , Fitosteroles/uso terapéutico , Muerte Celular , Emulsiones/química , Endocitosis , Citometría de Flujo , Células HT29 , Células Hep G2 , Humanos , Tamaño de la Partícula , Polvos , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad Estática , Temperatura
10.
Sci Rep ; 11(1): 5448, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33750853

RESUMEN

To safely re-open economies and prevent future outbreaks, rapid, frequent, point-of-need, SARS-CoV-2 diagnostic testing is necessary. However, existing field-deployable COVID-19 testing methods require the use of uncomfortable swabs and trained providers in PPE, while saliva-based methods must be transported to high complexity laboratories for testing. Here, we report the development and clinical validation of High-Performance Loop-mediated isothermal Amplification (HP-LAMP), a rapid, saliva-based, SARS-CoV-2 test with a limit of detection of 1.4 copies of virus per µl of saliva and a sensitivity and specificity with clinical samples of > 96%, on par with traditional RT-PCR based methods using swabs, but can deliver results using only a single fluid transfer step and simple heat block. Testing of 120 patient samples in 40 pools comprised of 5 patient samples each with either all negative or a single positive patient sample was 100% accurate. Thus, HP-LAMP may enable rapid and accurate results in the field using saliva, without need of a high-complexity laboratory.


Asunto(s)
/diagnóstico , Saliva/virología , /virología , Humanos , Límite de Detección , Técnicas de Diagnóstico Molecular , Nasofaringe/virología , Técnicas de Amplificación de Ácido Nucleico , ARN Viral/metabolismo , Sensibilidad y Especificidad , Temperatura
11.
J Environ Manage ; 286: 112167, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33676135

RESUMEN

In this study, the cellulose sulfate/chitosan aerogel (CCA) was prepared by chitosan and sulfonated cotton, and its efficiency was assessed for lead removal from contaminated waters. The adsorbent was determined by FESEM, EDS, FTIR, and BET analysis. The batch experiments were designed by Design-Expert software. At an initial lead concentration of 300 mg L-1, the contact time of 40 min, and the temperature of 26 °C, the maximum adsorption capacity and the removal efficiency were 137.8 mg g-1 and 91.9%, respectively. Also, the effect of ions including cations and anions at 100 mg L-1 was investigated, and it was found that the presence of anions does not have much effect on adsorption, but among cations, calcium and magnesium have the inhibitor effect on adsorption due to their double plosive. Adsorption isotherms were studied at different temperatures, and the kinetics of the reaction were investigated at different concentrations. Thermodynamic parameters indicated that the adsorption process was spontaneous, endothermic, and increasing irregularity at the adsorbent level. Adsorption recovery was performed five times adsorption and de-adsorption by hydrochloric acid 1 M washing and only 10% of adsorption capacity was decreased.


Asunto(s)
Quitosano , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Celulosa/análogos & derivados , Concentración de Iones de Hidrógeno , Cinética , Plomo , Temperatura , Termodinámica
12.
J Environ Manage ; 286: 112249, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33677345

RESUMEN

Understanding vegetation response to natural and anthropogenic forcings is vital for managing watersheds as natural ecosystems. We used a novel integrated framework to separate the impacts of natural factors (e.g. drought, precipitation and temperature) from those of anthropogenic factors (e.g. human activity) on vegetation cover change at the watershed scale. We also integrated several datasets including satellite remote sensing and in-situ measurements for a twenty-year time period (2000-2019). Our results show that despite no significant trend being observed in temperature and precipitation, vegetation indices expressed an increasing trend at both the control and treated watersheds. The vegetation cover was not significantly affected by the natural factors whereas the watershed management practice (as a human activity) had significant impacts on vegetation change in the long-term. Further, the vegetation cover long-term response to watershed management practice was mainly linear. We also found that the vegetation indices values in the 2011-2019 period (as the treated period in treated watershed) were significantly higher than those in the 2000-2010 period. In the short-term, however, the drought condition and decreased precipitation (as natural factors) explained the majority of the change in vegetation cover. For example, the majority of the breakpoints occurred in 2008, and it was related to a widespread extreme drought in the area. The watershed management practice as a human activity along with extreme climatic events could explain a large part of the vegetation changes observed in the treated and control watersheds.


Asunto(s)
Sequías , Ecosistema , Actividades Humanas , Humanos , Temperatura
13.
Bioresour Technol ; 329: 124924, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33691205

RESUMEN

For exploring the impact of temperature on antibiotic resistant genes (ARGs) during sludge anaerobic digestion (AD), the dynamic variations of sludge ARGs, plasmid ARGs, and cell-free ARGs in mesophilic (25 °C and 35 °C) and thermophilic (55 °C) digesters were investigated. The study revealed that the abundance of sludge ARGs and plasmid ARGs in thermophilic sludge AD was significantly lower than that in mesophilic digesters, while the cell-free ARGs abundance of the thermophilic digesters was similar to mesophilic digesters. Higher archaea abundance, lower bacteria abundance, and different microbial community were found in thermophilic digesters compared to that of mesophilic ones. Firmicutes might be a main group of potential hosts of ARGs in sludge AD. The distinct microbial community was the main contributor to the low ARGs abundance in thermophilic sludge AD. Thermophilic operation at 55 °C rather than mesophilic operation is more conducive to control ARGs in sludge anaerobic digestion.


Asunto(s)
Antibacterianos , Aguas del Alcantarillado , Anaerobiosis , Antibacterianos/farmacología , Bacterias/genética , Farmacorresistencia Microbiana/genética , Temperatura
14.
Bioresour Technol ; 329: 124907, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33706175

RESUMEN

To further explain effects of pyrolysis temperature on physicochemical properties of corn stalk pellet biochar from a new perspective, various lab physicochemical analysis methods combining microcomputed tomography were used to characterize biochar in this study. The results showed that at pyrolysis temperatures from 300 °C to 800 °C, yield of biochar decreased logarithmically with increasing pyrolysis temperature (T); changes of proximate and elemental compositions all showed significant differences, but the change rules were not consistent; high temperature pyrolysis biochar had high stability, high hardness and was convenient for storage and transportation; the proportions of hydroxyl group and amino group were highest in BC800 and BC600, respectively, contributing to the adsorption and removal of pollutants; BC400 had the best combustion performance; X-ray mean attenuation coefficient (XMAC) showed the following correlations, namely, XMAC = 0.003*ln(T-285.329) + 0.011 (R2 = 0.904) and XMAC = -0.031*(VM/100) + 0.021*(Ash/100) + 0.027 (R2 = 0.915). Above results provide important basic data support for development of corn stalk pellet biochar.


Asunto(s)
Pirólisis , Zea mays , Adsorción , Carbón Orgánico , Temperatura , Microtomografía por Rayos X
15.
Sci Total Environ ; 772: 144568, 2021 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-33770895

RESUMEN

BACKGROUND: Temperature stress was reported to impact the gut-brain axis including intestinal microbiome and neuroinflammation, but the molecular markers involved remain unclear. We aimed to examine the effects of different temperature stress on the intestinal microbiome and central nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasomes. MATERIALS AND METHODS: Mice models were established under low temperature (LT), room temperature (RT), high temperature (HT), and temperature variation (TV) respectively for seven days. We examined temperature-induced changes of intestinal microbiome composition and the levels of its metabolites short-chain fatty acids (SCFAs), as well as the expressions of central NLRP3 inflammasomes and inflammatory cytokines. Redundancy analysis and Spearman correlation analysis were performed to explore the relationships between microbiome and NLRP3 inflammasomes and other indicators. RESULTS: HT and LT significantly increased the Alpha diversity of intestinal microbiome. Compared with RT group, Bacteroidetes were most abundant in LT group while Actinobacteria were most abundant in HT and TV groups. Nineteen discriminative bacteria were identified among four groups. LT increased the expressions of acetate and propionate while decreased that of NLRP3 inflammasomes; HT decreased the expression of butyrate while increased that of NLRP3 inflammasomes, interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α; TV decreased the expression of propionate while increased that of NLRP3 inflammasomes and TNF-α. Microbiome distribution could significantly explain the differences in NLRP3 between comparison groups (LT&RT: R2 = 0.82, HT&RT: R2 = 0.86, TV&RT: R2 = 0.94; P < 0.05). The discriminative bacteria were significantly correlated with SCFAs but were correlated with NLRP3 inflammasomes and cytokines in the opposite direction. CONCLUSIONS: LT inhibits while HT and TV promote the activation of NLRP3 inflammasomes in brain, and intestinal microbiome and its metabolites may be the potential mediators. Findings may shed some light on the impact of temperature stress on gut-brain axis.


Asunto(s)
Microbioma Gastrointestinal , Inflamasomas , Animales , Encéfalo/metabolismo , Inflamasomas/metabolismo , Interleucina-1beta/metabolismo , Ratones , Proteína con Dominio Pirina 3 de la Familia NLR , Temperatura
16.
Sci Total Environ ; 772: 145039, 2021 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-33770902

RESUMEN

There has been much debate on the temporal change trend and existence of a turning point in spring green-up date (GUD) of plants on the Qinghai-Tibetan Plateau (QTP). Most previous studies on the QTP used remote sensing data, which have large uncertainties. In this study, using a large amount of long-term ground observation data at 27 phenological stations across the QTP (1694 GUD records), we showed that on the whole, QTP herbaceous plant GUD insignificantly advanced during 1982-2017. Although the direction of the GUD trend did not change from 1982 to 2017, the magnitude of the advancing trend greatly weakened after 1999. According to our estimated results from 28 paired GUD time series, the overall GUD trend shifted from -2.70 days/decade during 1982-1999 to -0.56 days/decade during 2000-2017. This finding contrasts with the conclusions of previous satellite-based studies, which either reported a continuous significant advancement of GUD or a turning point in the mid-to-late 1990s. Through partial correlation analysis and partial least squares regression, we found that winter and spring air temperatures were the primary climatic factors that influenced the temporal change in GUD, and both had negative effects on GUD. The decreased GUD trend was mainly attributable to the warming slowdown in spring. On average, the spring warming rate decreased by 52.43% after 1999, whereas the winter warming rate displayed no obvious change. This study also found that the GUD of forbs showed stronger sensitivity to air temperature change than that of sedges and grasses. This indicates that forbs are more competitive in adaptation to climate warming, which might shift plant community structure and affect ecosystem service function. Moreover, the declined advancement in GUD implies that the spring phenologically driven increase in carbon uptake may have also slowed in the past two decades.


Asunto(s)
Cambio Climático , Ecosistema , Estaciones del Año , Temperatura , Tibet
17.
Pestic Biochem Physiol ; 173: 104794, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33771265

RESUMEN

Climate change will be an additional issue to the challenge to manage herbicide resistant weeds. This work investigated the impact of three temperature regimes (10/5, 20/15 and 30/25 °C) on the efficacy, foliar retention, absorption and translocation of fomesafen, protoporphyrinogen oxidase (PPO) inhibitor, and imazamox, acetolactate synthase (ALS) inhibitor, between two Euphorbia heterophylla populations, one susceptible (S) and one multiple PPO and ALS resistant (R). The R population went from 5 (fomesafen) and 12 (imazamox) times more resistant than the S population at 10/5 °C to more than 100 times to both herbicides at 20/15 and 30/25 °C. Leaf retention of fomesafen was not affected by temperature; however, imazamox retention was less at 10/5 and 20/15 °C than at 30/25 °C, and the R population always retained less imazamox than the S population. 14C-fomesafen absorption was similar between populations, but lower amounts were absorbed at 10/5 °C regardless of the evaluation time. Recovered 14C-imazamox rates decreased in both populations as the evaluation time increased, ranging from 82 to 92% at 6 h after treatment (HAT), and from 47 to 76% at 48 HAT, depending on the temperature regime. The 14C-imazamox losses were greater from 24 HAT in R plants grown at 30/25 °C and in all temperature regimes at 48 HAT. Although both populations translocated large amounts of imazamox, the S population distributed it in the rest of the plant (33%) and roots (15%), while the R population kept it mainly on the treated leaf (24%) or lost ~20% more herbicide than S population at 48 HAT, indicating the need for further studies on root exudation between these populations. Low temperatures reduced resistance levels to fomesafen and imazamox in E. heterophylla, suggesting that temperature influences the expression of the mechanisms that govern this multiple resistance.


Asunto(s)
Acetolactato Sintasa , Euphorbia , Herbicidas , Benzamidas , Resistencia a los Herbicidas , Herbicidas/farmacología , Imidazoles , Temperatura
18.
Environ Monit Assess ; 193(4): 233, 2021 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-33772652

RESUMEN

Deltas are geographically and socio-ecologically distinct systems, with a unique climate and contextually high vulnerabilities to climate dynamics. Hence, they require specific climate change adaptation and policy responses, informed by delta-scale analysis. However, available climate knowledge on deltas is based mainly on broad-scale analysis that masks information unique to deltas. This applies to the Volta Delta system of Ghana. This study presents annual and intra-annual climate variability and trend analysis carried out across the Volta Delta, using the coefficient of variation (CV), anomaly, Mann-Kendall and Pettit statistics. There were time and space differences in climate change and variability. Statistically significant (P < 0.05) positive trends were observed for the major wet season and the mean annual rainfall for Ada and highly significant (P < 0.01) positive trends for Akatsi. These contrasted with the observations in Adidome, which experienced a statistically highly significant (P < 0.01) decreasing trend in rainfall. There were significant (P< 0.05) increases in annual minimum, maximum, and mean temperatures over time in both coastal and inland delta stations. The annual rate of change of mean temperature ranged from 0.03 to 0.05. Ada, the more coastal location, has experienced a narrow range of temperature change, most probably due to the buffering capacity of the ocean. Point changes were observed in the climate data series in four (4) localities. We recommend that adaption and policy actions should include, the provision of small-scale irrigation, encouraging adoption of drought-resistant crop varieties and crop diversification, and also be made responsive to the existing spatiotemporal climate variability and change within the Volta Delta.


Asunto(s)
Monitoreo del Ambiente , Lluvia , Cambio Climático , Ghana , Temperatura
19.
Environ Sci Pollut Res Int ; 28(14): 18284-18293, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33665692

RESUMEN

The objective of this study was to check the potential of crude xylano-pectinolytic enzymes in bleaching of rice straw pulp, in order to reduce the toxic waste load for managing the environmental pollution. The xylano-pectinolytic enzymatic bleaching step for delignification was found to be most effective at pulp consistency 1:10 g/ml, xylanase:pectinase dose of 9:4 IU/ml, pH 8.5 and treatment time 180 min at temperature of 55 °C, and resulted in lowering of kappa number of the rice straw pulp by 15.29%. In subsequent bleaching stages, this enzymatic pre-bleaching treatment also resulted in 30% reduction of active chlorine dioxide dose without any loss of optical properties. Significant improvement in various physical properties of the enzymes treated pulp, tear index (15.43%), breaking length (11.11%), double fold number (25.92%), burst index (9.88%) and viscosity (13.63%), and Gurley porosity (39.86%) was also noticed. This approach resulted in reduction of BOD and COD values by 21.07% and 26.57%, respectively. This is the first study on the use of crude xylano-pectinolytic enzymes for bio-bleaching of rice straw pulp.


Asunto(s)
Oryza , Papel , Poligalacturonasa , Compuestos de Sodio , Temperatura
20.
Science ; 371(6533)2021 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-33674467

RESUMEN

The mechanisms that underly the adaptation of enzyme activities and stabilities to temperature are fundamental to our understanding of molecular evolution and how enzymes work. Here, we investigate the molecular and evolutionary mechanisms of enzyme temperature adaption, combining deep mechanistic studies with comprehensive sequence analyses of thousands of enzymes. We show that temperature adaptation in ketosteroid isomerase (KSI) arises primarily from one residue change with limited, local epistasis, and we establish the underlying physical mechanisms. This residue change occurs in diverse KSI backgrounds, suggesting parallel adaptation to temperature. We identify residues associated with organismal growth temperature across 1005 diverse bacterial enzyme families, suggesting widespread parallel adaptation to temperature. We assess the residue properties, molecular interactions, and interaction networks that appear to underly temperature adaptation.


Asunto(s)
Adaptación Fisiológica , Proteínas Bacterianas/química , Evolución Molecular , Esteroide Isomerasas/química , Sustitución de Aminoácidos , Proteínas Bacterianas/genética , Estabilidad de Enzimas , Mutación , Esteroide Isomerasas/genética , Temperatura
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