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1.
Pestic Biochem Physiol ; 201: 105860, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38685214

RESUMO

The Osiris gene family is believed to play important roles in insect biology. Previous studies mainly focused on the roles of Osiris in Drorophila, how Osiris operates during the development of other species remains largely unknown. Here, we investigated the role of LmOsi17 in development of the hemimetabolous insect Locusta migratoria. LmOsi17 was highly expressed in the intestinal tract of nymphs. Knockdown of LmOsi17 by RNA interference (RNAi) in nymphs resulted in growth defects. The dsLmOsi17-injected nymphs did not increase in body weight or size and eventually died. Immunohistochemical analysis showed that LmOsi17 was localized to the epithelial cells of the foregut and the gastric caecum. Histological observation and hematoxylin-eosin staining indicate that the foregut and gastric caecum are deformed in dsLmOsi17 treated nymphs, suggesting that LmOsi17 is involved in morphogenesis of foregut and gastric caecum. In addition, we observed a significant reduction in the thickness of the new cuticle in dsLmOsi17-injected nymphs compared to control nymphs. Taken together, these results suggest that LmOsi17 contributes to morphogenesis of intestinal tract that affects growth and development of nymphs in locusts.


Assuntos
Proteínas de Insetos , Locusta migratoria , Morfogênese , Ninfa , Animais , Locusta migratoria/crescimento & desenvolvimento , Locusta migratoria/genética , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética , Ninfa/crescimento & desenvolvimento , Interferência de RNA , Intestinos
2.
Insect Sci ; 31(3): 748-758, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38445520

RESUMO

Lipid homeostasis is crucial for growth and development of organisms. Several cytochrome P450 monooxygenases (CYPs) are involved in lipid metabolism. The function of Cyp311a1 in the anterior midgut as a regulator of phosphatidylethanolamine (PE) metabolism in Drosophila melanogaster has been demonstrated, as depletion of Cyp311a1 caused larval growth arrest that was partially rescued by supplying PE. In this study, we investigated the role of CYP311A1 in wing morphogenesis in Drosophila. Using the GAL4-UAS system, Cyp311a1 was selectively knocked down in the wing disc. A deformed wing phenotype was observed in flies with reduced Cyp311a1 transcripts. BODIPY and oil red O staining revealed a reduction of neutral lipids in the wing disc after the depletion of Cyp311a1. In addition, we observed an enhanced sensitivity to Eosin Y penetration in the wings of Cyp311a1 knocked-down flies. Moreover, the reduction of CYP311A1 function in developing wings does not affect cell proliferation and apoptosis, but entails disordered Phalloidin or Cadherin distribution, suggesting an abnormal cell morphology and cell cortex structure in wing epithelial cells. Taken together, our results suggest that Cyp311a1 is needed for wing morphogenesis by participating in lipid assembly and cell homeostasis.


Assuntos
Sistema Enzimático do Citocromo P-450 , Proteínas de Drosophila , Drosophila melanogaster , Asas de Animais , Animais , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Asas de Animais/crescimento & desenvolvimento , Asas de Animais/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Morfogênese , Larva/crescimento & desenvolvimento , Larva/genética , Larva/metabolismo , Metabolismo dos Lipídeos
3.
Insect Biochem Mol Biol ; 168: 104114, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38552809

RESUMO

The Drosophila hindgut is a classical model to study organogenesis. The adult hindgut originates from the precursor cells in the larval hindgut. However, the territory of these cells has still not been well determined. A ring of wingless (wg)-expressing cells lies at the anterior zone of both the larval and adult hindgut. The larval Wg ring was thought as a portion of precursor of the adult hindgut. By applying a cell lineage tracing tool (G-TRACE), we demonstrate that larval wg-expressing cells have no cell lineage contribution to the adult hindgut. Additionally, adult Wg ring cells do not divide and move posteriorly to replenish the hindgut tissue. Instead, we determine that the precursors of the adult pylorus and ileum are situated in the cubitus interruptus (ci)-expressing cells in the anterior zone, and deduce that the precursor stem cells of the adult rectum locate in the trunk region of the larval pylorus including hedgehog (hh)-expressing cells. Together, this research advances our understanding of cell lineage origins and the development of the Drosophila hindgut.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Larva/genética , Larva/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteína Wnt1 , Proteínas Hedgehog/genética , Regulação da Expressão Gênica no Desenvolvimento
4.
J Food Sci ; 89(3): 1616-1631, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38328981

RESUMO

To quickly calibrate the discrete element parameters (DEP) of pellets with different moisture content (MC), the angle of repose (AoR) was taken as the target value to conduct experimental and simulation research on gluten pellets. The experimental method obtained the intrinsic parameters, contact parameters, and AoR of pellets with different moisture content. The parameters differed significantly under different moisture content (p < 0.05). The AoR-MC model (R2  = 0.987) was established. The Plackett-Burman test, steepest ascent test, and center compound test were carried out to establish the AoR-DEP model (R2  = 0.969) with a relative error less than or equal to 2.07%. The MC-DEP model was derived, and verified by the side plate lifting method with a relative error less than or equal to 2.58%. This paper provides a new method for calibrating DEP under different moisture content.


Assuntos
Calibragem
5.
Int J Biol Macromol ; 263(Pt 2): 130245, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38367779

RESUMO

The dynamic adhesion between cells and their extracellular matrix is essential for the development and function of organs. During insect wing development, two epithelial sheets contact each other at their basal sites through the interaction of ßPS integrins with the extracellular matrix. We report that Osiris17 contributes to the maintenance of ßPS integrins localization and function in developing wing of Drosophila and locust. In flies with reduced Osiris17 expression the epithelia sheets fail to maintain the integrity of basal cytoplasmic junctional bridges and basal adhesion. In contrast to the continuous basal integrin localization in control wings, this localization is disrupted during late stages of wing development in Osiris17 depleted flies. In addition, the subcellular localization revealed that Osiris17 co-localizes with the endosomal markers Rab5 and Rab11. This observation suggests an involvement of Osiris17 in endosomal recycling of integrins. Indeed, Osiris17 depletion reduced the numbers of Rab5 and Rab11 positive endosomes. Moreover, overexpression of Osiris17 increased co-localization of Rab5 and ßPS integrins and partially rescued the detachment phenotype in flies with reduced ßPS integrins. Taken together, our data suggest that Osiris17 is an endosome related protein that contributes to epithelial remodeling and morphogenesis by assisting basal integrins localization in insects.


Assuntos
Proteínas de Drosophila , Integrinas , Animais , Integrinas/metabolismo , Drosophila/genética , Epitélio/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Matriz Extracelular/metabolismo
6.
Natl Sci Rev ; 10(11): nwad251, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37900194

RESUMO

Water input budget of global oceanic lithosphere at different tectonic settings are quantitatively estimated. The results indicate that the hydration at subduction zone is fundamentally essential to plate dynamics and water cycle of the Earth.

7.
RSC Adv ; 13(29): 20113-20123, 2023 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-37416912

RESUMO

In wastewater treatment plants (WWTPs), external carbon sources are often required due to low C/N influent. However, the use of external carbon sources can increase treatment costs and cause large carbon emissions. Beer wastewater, which contains a substantial amount of carbon, is often treated separately in China, consuming significant energy and cost. However, most studies using beer wastewater as an external carbon source are still on a laboratory scale. To address this issue, this study proposes using beer wastewater as an external carbon source in an actual WWTP to reduce operating costs and carbon emissions while achieving a win-win situation. The denitrification rate of beer wastewater was found to be higher than that of sodium acetate , resulting in improved treatment efficiency of the WWTP. Specifically, COD, BOD5, TN, NH4+-N and TP increased by 3.4%, 1.6%, 10.8%, 1.1%, and 1.7%, respectively. Additionally, the treatment cost and carbon emission per 10 000 tons of wastewater treated were reduced by 537.31 yuan and 2.27 t CO2, respectively. These results indicate that beer wastewater has significant utilization potential and provide a reference for using different types of production wastewater in WWTPs. This study's findings demonstrate the feasibility of implementing this approach in an actual WWTP setting.

8.
Adv Mater ; 35(45): e2302530, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37332101

RESUMO

Mechanical metamaterials are meticulously designed structures with exceptional mechanical properties determined by their microstructures and constituent materials. Tailoring their material and geometric distribution unlocks the potential to achieve unprecedented bulk properties and functions. However, current mechanical metamaterial design considerably relies on experienced designers' inspiration through trial and error, while investigating their mechanical properties and responses entails time-consuming mechanical testing or computationally expensive simulations. Nevertheless, recent advancements in deep learning have revolutionized the design process of mechanical metamaterials, enabling property prediction and geometry generation without prior knowledge. Furthermore, deep generative models can transform conventional forward design into inverse design. Many recent studies on the implementation of deep learning in mechanical metamaterials are highly specialized, and their pros and cons may not be immediately evident. This critical review provides a comprehensive overview of the capabilities of deep learning in property prediction, geometry generation, and inverse design of mechanical metamaterials. Additionally, this review highlights the potential of leveraging deep learning to create universally applicable datasets, intelligently designed metamaterials, and material intelligence. This article is expected to be valuable not only to researchers working on mechanical metamaterials but also those in the field of materials informatics.

9.
Insects ; 14(5)2023 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-37233034

RESUMO

Group I chitin deacetylases (CDAs), CDA1 and CDA2, play an essential role in cuticle formation and molting in the process of insect wing development. A recent report showed that trachea are able to take up a secreted CDA1 (serpentine, serp) produced in the fat body to support normal tracheal development in the fruit fly Drosophila melanogaster. However, whether CDAs in wing tissue were produced locally or derived from the fat body remains an open question. To address this question, we applied tissue-specific RNAi against DmCDA1 (serpentine, serp) and DmCDA2 (vermiform, verm) in the fat body or the wing and analyzed the resulting phenotypes. We found that repression of serp and verm in the fat body had no effect on wing morphogenesis. RT-qPCR showed that RNAi against serp or verm in the fat body autonomously reduced their expression levels of serp or verm in the fat body but had no non-autonomous effect on the expression in wings. Furthermore, we showed that inhibition of serp or verm in the developing wing caused wing morphology and permeability deficiency. Taken together, the production of Serp and Verm in the wing was autonomous and independent of the fat body.

10.
Insect Mol Biol ; 32(6): 583-591, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37212394

RESUMO

Insect halteres, as specialised hind wings, play an important role during aerial manoeuvres. In Drosophila, halteres and wings are homologous appendages with different morphology. Previous studies have focused on the metamorphosis of halteres, while current knowledge about its cell lineage and regional compartmentalization is still limited. In this study, we performed cell-lineage tracing of canonical landmark signals in halteres and present a simple model for haltere development. Cell lineage tracing in wings was used as a reference. The nub showed wing-like expressions in halteres, whereas hth and pnr exhibited different expressions in adult wings and halteres. The lineage tracing revealed that the pouch region gives rise to end-bulb, and hinge cells contribute to proximal haltere formation. Moreover, we demonstrated that twi-expressing cells participate in the cell population of the distal end-bulb. Haematoxylin and eosin staining indicated that muscle cells were present at the distal end-bulb. These results indicated that adult halteres displayed unique cell lineage patterns and the muscle cells are important components of end-bulbs.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Linhagem da Célula , Asas de Animais , Drosophila melanogaster/fisiologia
11.
Nat Commun ; 14(1): 2710, 2023 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-37169745

RESUMO

Water is the most common volatile component inside the Earth. A substantial amount of water can be carried down to the interior of the Earth by subducting plates. However, how the subducted water evolves after the subducting slab breaks off remains poorly understood. Here we use the data from a passive seismic experiment using ocean bottom seismometers (OBSs) together with the land stations to determine the high-resolution, three-dimensional seismic structure of the Southwest Sub-basin (SWSB) of the South China Sea (SCS). At depths below 40 km, the mantle shear velocity (Vsv) beneath the northern side of the SWSB is similar to that of the conventional oceanic pyrolite mantle, but roughly 3% shear-velocity reduction is found beneath the southern side of the SWSB. Results of thermal dynamic modeling reveal that the observed shear-velocity reduction could be explained by the presence of 150-300 ppm of water and 5-10% of lower continental crust. The inferred high-water content at the southern side of the SWSB is consistent with a model in which the Proto-SCS plate subducted southward prior to and during the formation of the SCS basin, releasing water into the upper mantle of the SWSB.

12.
Rejuvenation Res ; 25(4): 181-190, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35726384

RESUMO

Astragali Radix is the dry root of the leguminous plants Astragalus membranaceus (Fisch.) Bge. Var. mongholicus (Bge.) Hsiao and A. membranaceus (Fisch.) Bge. Astragali Radix is mostly used clinically as a decoction. A number of pharmacological studies show that Astragalus extract can increase telomerase activity and has antioxidation, anti-inflammatory, immune regulation, anticancer, lowering blood lipid, lowering blood sugar, and other effects. However, the anti-aging mechanism of aqueous extract from Astragali Radix (ARE) is still unclear. In this study, we evaluated the anti-aging effect of ARE on Drosophila melanogaster and investigated the underlying mechanism. The results of life span assay showed that 1.25 mg/mL of ARE can significantly prolong the life span of D. melanogaster in a natural aging model and protect against H2O2 and paraquat. Meanwhile, ARE can improve the climbing ability and food intake of flies. Metabolomics and the glutamate content assay suggested that ARE prevented an age-dependent increase in glutamate levels in D. melanogaster. Furthermore, ARE showed a dose-dependent effect on the scavenging ability of α, α-diphenyl-ß-picrylhydrazyl in vitro. Superoxide dismutase and catalase activities in the aging group also increased after the intervention of ARE. The data and the findings described here support the notion that ARE may play a preventive role in aging by improving the climbing ability, eliminating harmful free radicals accumulated in D. melanogaster and triggering antioxidant responses.


Assuntos
Astragalus propinquus , Drosophila melanogaster , Envelhecimento , Animais , Antioxidantes/farmacologia , Glutamatos , Peróxido de Hidrogênio
13.
Cell Mol Life Sci ; 79(5): 261, 2022 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-35478270

RESUMO

Lipids are either taken up from food sources or produced internally in specialized tissues such as the liver. Among others, both routes of lipid metabolism involve cytochrome P450 monooxygenases (CYPs). We sought to analyze the function of Cyp311a1 that has been shown to be expressed in the midgut of the fruit fly Drosophila melanogaster. Using a GFP-tagged version of CYP311A1 that is expressed under the control of its endogenous promoter, we show that Cyp311a1 localizes to the endoplasmic reticulum in epithelial cells of the anterior midgut. In larvae with reduced Cyp311a1 expression in the anterior midgut, compared to control larvae, the apical plasma membrane of the respective epithelial cells contains less and shorter microvilli. In addition, we observed reduction of neutral lipids in the fat body, the insect liver, and decreased phosphatidylethanolamine (PE) and triacylglycerols (TAG) amounts in the whole body of these larvae. Probably as a consequence, they cease to grow and eventually die. The microvillus defects in larvae with reduced Cyp311a1 expression are restored by supplying PE, a major phospholipid of plasma membranes, to the food. Moreover, the growth arrest phenotype of these larvae is partially rescued. Together, these results suggest that the anterior midgut is an import hub in lipid distribution and that the midgut-specific CYP311A1 contributes to this function by participating in shaping microvilli in a PE-dependent manner.


Assuntos
Drosophila melanogaster , Lipídeos , Animais , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Larva , Microvilosidades
14.
Ying Yong Sheng Tai Xue Bao ; 32(6): 2147-2157, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34212621

RESUMO

Information on the spatial distribution of soil microbial communities on the Tibetan Pla-teau is critical for in-depth understanding the important roles of microbes in typical alpine ecosystems. In this study, 16S rDNA Illumina Miseq sequencing was used to analyze the variations in bacterial community composition and functional potentials in soils sampled from four elevations on Mount Segrila, Tibet, and the driving environmental factors. Results showed that richness and Shannon diversity index of soil bacteria significantly decreased with increasing altitude. The relative abundances of Acidobacteria, Chloroflexi, Gemmatimonadetes, and Nitrospirae significantly increased, whereas that of Proteobacteria, Actinobacteria and Bacteroidetes significantly decreased with increasing altitude. In KEGG pathway (level Ⅱ), the relative abundance of genes related to membrane transport and the metabolism of amino acids, lipids, terpenoids and polyketones was significantly lower at high elevations. In contrast, genes related to carbohydrates metabolism, signal transduction, replication and repair and enzyme family were more abundant at high altitudes. Soil bacterial community composition and predicted functions were significantly affected by vegetation types and soil properties, with soil pH being the key driver. There were significant correlations between the abundances of predicted functions and bacterial taxa, such as Acitnobacteria, Bacteroidetes, and Fibrobacteres. The dissimilarity in the composition of KEGG pathway genes along the elevational gradient (ß-diversity) showed a significantly positive correlation with the dissimilarity in bacterial community structure, indicating that there was a strong relationship between microbial community composition and potential functionality.


Assuntos
Microbiologia do Solo , Solo , Bactérias/genética , China , RNA Ribossômico 16S , Tibet
15.
J Chromatogr A ; 1638: 461882, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33453657

RESUMO

This paper reported a headspace gas chromatography (HS-GC) for the determination of denitrifying enzyme activity in soil samples. It was based on measuring the NO2 signal in a set of closed/air-free vials containing soil samples that incubated at the designated conditions. The results showed that the method has a good measurement precision (RSD < 5.0%) and reasonable accuracy for determining the denitrifying enzyme activity in soil samples. It is simple and efficient, and very suitable to be used in batch sample analysis.


Assuntos
Cromatografia Gasosa/métodos , Desnitrificação , Enzimas/metabolismo , Solo/química , Calibragem , Dióxido de Nitrogênio/análise , Tamanho da Amostra , Fatores de Tempo
16.
Sci Total Environ ; 767: 144350, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33434843

RESUMO

The effect of different fertilization strategies on changes in soil organic carbon (SOC) largely depends on the current status of a given agricultural region. We analysed the results of 90 long-term field trials (20-37 years) in Chinese croplands to determine the effects of fertilization strategies [i.e., no fertilizer (CK), chemical fertilizer (NPK), manure only (M) and manure plus chemical fertilizers (NPKM)] on soil organic carbon stock (SOCs) at 0-20 cm depth in the North (NC), Northeast (NEC), Northwest (NWC) and South (SC) China. Compared with initial values, SOCs increased by 24-68% and 24-74% under NPKM and M applications, respectively, over the experimental periods. Furthermore, final SOCs under NPKM in NEC and NWC were significantly higher than those under other treatments, but there was no significant difference between NPKM and M in SC and no significant differences among fertilizer treatments in NC. Average SOC stock change rates (SOCr) were positive under all treatments for all regions except for CK and NPK in NEC, which were negative. There were regional differences in treatment effects: all treatments showed significantly different rates in NC and NWC, whereas there were no significant differences between the M and NPKM in NEC and SC. Random forest (RF) modeling showed that among the selected variables initial SOCs was the most important in accounting for differences in SOCr, followed by soil bulk density, mean annual temperature and precipitation for all treatments. Soil total nitrogen content was also an important explanatory variable for SOCr for CK and NPK, and soil pH for M. This study has highlighted the main driving variables of SOC change which can be of use in optimizing fertilization strategies, by taking account of the baseline SOCs status and environmental factors for different regions, to minimize soil carbon emissions while maximizing carbon sequestration in soils.

17.
Insect Sci ; 27(6): 1198-1207, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32129536

RESUMO

Wings are essential for insect fitness. A number of proteins and enzymes have been identified to be involved in wing terminal differentiation, which is characterized by the formation of the wing cuticle. Here, we addressed the question whether chitinase 10 (Cht10) may play an important role in chitin organization in the wings of the fruit fly Drosophila melanogaster. Initially, we first found that Cht10 expression coincides with the expression of the chitin synthase coding gene kkv. This suggests that the respective proteins may cooperate during wing differentiation. In tissue-specific RNA interference experiments, we demonstrate that suppression of Cht10 causes an excess in chitin amounts in the wing cuticle. Chitin organization is severely disrupted in these wings. Based on these data, we hypothesize that Cht10 restricts chitin amounts produced by Kkv in order to ensure normal chitin organization and wing cuticle formation. In addition, we found by scanning electron microscopy that Cht10 suppression also affects the cuticle surface. In turn, cuticle inward permeability is enhanced in Cht10-less wings. Moreover, flies with reduced Cht10 function are unable to fly. In conclusion, Cht10 is essential for wing terminal differentiation and function.


Assuntos
Quitina/metabolismo , Drosophila melanogaster/metabolismo , Asas de Animais/metabolismo , Animais , Drosophila melanogaster/crescimento & desenvolvimento , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Asas de Animais/crescimento & desenvolvimento
18.
Insect Sci ; 27(1): 14-21, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31246335

RESUMO

Manipulating an exogenous or endogenous gene of interest at a defined level is critical for a wide variety of experiments. The Gal4/UAS system has been widely used to direct gene expression for studying complex genetic and biological problems in Drosophila melanogaster and other model organisms. Driven by a given tissue-specific Gal4, expressing UAS-transgene or UAS-RNAi (RNA interference) could be used to up- or down-regulate target gene expression, respectively. However, the efficiency of the Gal4/UAS system is roughly predefined by properties of transposon vector constructs and the insertion site in the transgenic stock. Here, we describe a simple way to modulate optomotor blind (omb) expression levels in its endogenous expression region of the wing disc. We co-expressed UAS-omb and UAS-omb-RNAi together under the control of dpp-Gal4 driver which is expressed in the omb expression region of the wing pouch. The repression effect is more sensitive to temperature than that of overexpression. At low temperature, overexpression plays a dominant role but the efficiency is attenuated by UAS-omb-RNAi. In contrast, at high temperature RNAi predominates in gene expression regulation. By this strategy, we could manipulate omb expression levels at a moderate level. It allows us to manipulate omb expression levels in the same tissue between overexpression and repression at different stages by temperature control.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas do Tecido Nervoso/genética , Proteínas com Domínio T/genética , Asas de Animais/crescimento & desenvolvimento , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/crescimento & desenvolvimento , Animais Geneticamente Modificados/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Transdução de Sinais , Proteínas com Domínio T/metabolismo
19.
Sci Total Environ ; 701: 134660, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31704401

RESUMO

The biogeochemical cycles of plant nitrogen (N) and phosphorus (P) are interlinked by ecological processes, and the N and P cycles become uncoupled in response to global change experiments. However, the complex natural hydrothermal conditions in arid, semiarid and humid grassland ecosystems may have different effects on the availability of soil nutrients and moisture and may induce different balances between the N and P cycles. Here, we evaluated how the aridity index (AI) affects the balance between N and P of alpine grassland by the collected 115 sites along water and heat availability gradients on the Tibetan Plateau. We found that AI was negatively related to the variation in the coefficients of soil total dissolved N (TDN) and soil availability of P (SAP), and positive effects of AI, TDN and SAP on the coupling of plant N and P were detected. Thus, AI was positively correlated with soil nutrients and moisture, which may favor the co-uptake of soil nutrients by plants, resulting in a small variation in plant N and P in humid environments. Conversely, in arid environments with temporally variable soil nutrients, the plants tend to be more flexible in their N:P stoichiometry. Generally, our findings suggest that plant N and P could be more strongly coupled in humid conditions than in arid environments across alpine grasslands, with potential decoupling of the N biogeochemical cycle from P in an arid environment with an asynchronous dynamic of temperature and precipitation.


Assuntos
Monitoramento Ambiental , Pradaria , Nitrogênio/análise , Fósforo/análise , Microbiologia do Solo , Ecossistema , Temperatura , Água
20.
Artigo em Inglês | MEDLINE | ID: mdl-31671530

RESUMO

The assessment of soil organic carbon (SOC) in mountainous karst areas is very challenging, due to the high spatial heterogeneity in SOC content and soil type. To study and assess the SOC storage in mountainous karst areas, a total of 22,786 soil samples were collected from 2,854 soil profiles in Guizhou Province in Southwest China. The SOC content in the soil samples was determined by the oxidation of potassium dichromate (K2Cr2O7), followed by titration with iron (II) sulfate (FeSO4). The SOC storage was assessed based on different land uses. The results suggested that the average SOC density in the top 1.00 m of soil associated with different land uses decreased in the following order: Croplands (9.58 kg m-2) > garden lands (9.07 kg m-2) > grasslands (8.07 kg m-2) > forestlands (7.35 kg m-2) > uncultivated lands (6.94 kg m-2). The SOC storage values in the 0.00-0.10 m, 0.00-0.20 m, 0.00-0.30 m and 0.00-1.00 m soil layers of Guizhou Province were 0.50, 0.87, 1.11 and 1.58 Pg, respectively. The SOC in the top 0.30 m of soil accounted for 70.25% of the total within the 0.00-1.00 m layer in Guizhou Province. It was concluded that assessing SOC storage in mountainous karst areas was more accurate when using land use rather than soil type. This result can supply a scientific reference for the accurate assessment of the SOC storage in the karst areas of southwestern China, the islands of Java, northern and central Vietnam, Indonesia, Kampot Province in Cambodia and in the general area of what used to be Yugoslavia, along with other karst areas with similar ecological backgrounds.


Assuntos
Agricultura , Carbono/análise , Ecossistema , Monitoramento Ambiental/métodos , Solo/química , China
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