As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions...As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions modify organic carbon （SOC）, nitrogen （N） and phosphorus dynamics, bulk density and water-holding capacity and biological activities in soils, but little is known with regard to soil exchange properties. Variation in soil ex- changeable base cations was examined under C. microphylla plantations with an age sequence of 0, 5, 10, and 22 years in the Horqin Sandy Land, and at the depth of 0-10, 10-20, and 20-30 cm, respectively. C. microphylla has been planted on the non-vegetated sand dunes with similar physical-chemical soil properties. The results showed that exchangeable calcium （Ca）, magnesium （Mg）, and potassium （K）, and cation exchange capacity （CEC） were significantly increased, and Ca saturation tended to decrease, while Mg and K saturations were increased with the plantation years. No difference was observed for exchangeable sodium （Na） neither with plantation years nor at soil depths. Of all the base cations and soil layers, exchangeable K at the depth of 0-10 cm accumulated most quickly, and it increased by 1.76, 3.16, and 4.25 times, respectively after C. microphylla was planted for 5, 10, and 22 years. Exchangeable Ca, Mg, and K, and CEC were significantly （P〈0.001） and positively correlated with SOC, total N, pH and electrical conductivity （EC）. Soil pH and SOC are regarded as the main factors influencing the variation in ex- changeable cations, and the preferential absorption of cations by plants and different leaching rates of base cations that modify cation saturations under C. microphylla plantation. It is concluded that as a nitrogen-fixation species, C. microphylla plantation is beneficial to increasing exchangeable base cations and CEC in soils, and therefore can improve soil fertility and create favorable microenvironments for plants and creatures in the semi-arid sandy land ecosystems.展开更多
Understanding the effects of vegetation cover on seedling survival is helpful for promoting vegetation restoration in environmentally fragile zones. This study was conducted in the desertified, moving sand dunes of Ho...Understanding the effects of vegetation cover on seedling survival is helpful for promoting vegetation restoration in environmentally fragile zones. This study was conducted in the desertified, moving sand dunes of Horqin Sandy Land, Inner Mongolia, northeastern China. We hyphothesized that （1） seed density （i.e., number/m2） increases as vegetation cover increases, and （2） there will be more surviving seedlings in locations with higher vegetation covers. Total vegetation cover and initial densities of seeds, germinated seeds and surviving seedlings of Ulmus pumilia were evaluated under various vegetation covers in trying to clarify the effects of vegetation cover on the early stages of the plant life history. In agreement with the first hypothesis, initial seed densities were greater （P〈0.05） under higher vegetation covers. The relationship between vegetation cover and initial seed density was represented by a quadratic regression, where a threshold occurred with a vegetation cover of 36% （P〈0.05）. The higher total vegetation covers, however, did not result in increased densities of germinated seeds （P〉0.05）, which on average represented 16.7% of initial seed densities. Even more, three months after the study initiation, total vegetation covers were similar （P〉0.05） at all positions in the dunes, and they determined a similar number （P〉0.05） of surviving seedlings at those positions （i.e. the second hypothesis had to be rejected）. The mean number of seedlings that survived at all positions was only 4.5% of germinated seeds. The number of surviving elm seedlings （0 to 1.7 seedlings/m2） under various vegetations covers （12.2% to 20.8%） at all dune positions by late summer would most likely not contribute to vegetation restoration in the study area.展开更多
Caragana microphylla Lam., a leguminous shrub species, plays an important role in revegetation in the degraded ecosystems of the Horqin Sandy Land, Northeastern China. Large areas planted with this shrub have been art...Caragana microphylla Lam., a leguminous shrub species, plays an important role in revegetation in the degraded ecosystems of the Horqin Sandy Land, Northeastern China. Large areas planted with this shrub have been artificially established as sand binders for soil protection, which might change the composition of soil bacterial communities with the development of sand dune stabilization. In this paper, we investigated the diversity and composition of native soil bacterial communities in the C. microphylla plantation for sand fixation using polymerase chain reaction with denaturing gradient gel electrophoresis（PCR-DGGE） to understand the influence of this plantation on sandy soil ecosystem development. We collected soil samples from plantations with an age sequence of 0, 9, 16, and 26 years, as well as from the natural community, to identify the differences among soil bacterial communities. The result showed that bacterial abundance and community composition in the sandy land were affected by the age of the C. microphylla plantation. Moreover, bacterial diversity decreased with increasing plantation age, and the composition of the bacterial community in the 26-year plantation was similar to that in the natural community. Phylogenetic analysis of bands excised from the DGGE gels showed that members of alpha Proteobacterium, gamma Proteobacterium, Gemmatimonadetes and Chloroflexi were dominant in the sandy land. The stabilization of moving sand dune and development of sand-fixed plantation resulted in an increase of soil fertility, which could drive the structural evolvement of soil bacterial community, and it needs over 20 years for the soil bacterial community to form a stable structure, similar to the case for the natural vegetation.展开更多
Two psammophile-dominated Artemisia semi-shrubs （A. wudanica and A. halodendron） and two annual Artemisia forbs （A. sieversiana and A. scoparia） bear significant ecological functions in Horqin Sandy Land, but syst...Two psammophile-dominated Artemisia semi-shrubs （A. wudanica and A. halodendron） and two annual Artemisia forbs （A. sieversiana and A. scoparia） bear significant ecological functions in Horqin Sandy Land, but systematical information on their achenes＇ germination is very limited. A set of studies were conducted to evaluate seed germination responses to storage periods and methods, different temperatures, lights conditions and sand burial depths, in order to determine inter-specific germination variation in the same genus and to explain how the species adapt to its microhabitat. Fresh achenes of A. wudanica, A. halodendron and A. sieversiana showed high germination capacities, but those of A. scoparia had obvious innate dormancy, which could be broken by chilling and dry storage, especially long-term dry storage. Achene germination of the two semi-shrubs preferred lower temperature fluctuation （10 to 22℃） and was not sensitive to light. But the two annuals preferred higher temperature fluctuation （34 to 22℃） and strong light for their achene germination. These four Artemisia species showed similar responses to sand burial, i.e. soil surface was most favorable for seedling emergence, and the deeper the sand burial, the fewer the seedling emergence. For the two semi-shrubs, their microhabitats are sand dunes with high temperature and intense light, which are not favorable for germination and seedling survival. Only rainfall contributes to temporary decrease of temperature and then triggers germination. We deduced that germination is not the main but a supplementary repro- ductive mode for the two semi-shrubs in sand dunes. For the two annuals, achene germination is the only reproductive mode, but different responses have been developed for microhabitat adaptation. For A. sieversiana, high germination capacities in wide temperature ranges and all light conditions could improve its competition and advancement in the wettest microhabitats. For A. scoparia, obvious innate dormancy of fresh achenes and germination inhabitation under unfavorable conditions are important adaptation to environmental disturbances.展开更多
Species richness and abundance are two important species diversity variables that have attracted particular attention because of their significance in determining present and future species composition conditions. Thi...Species richness and abundance are two important species diversity variables that have attracted particular attention because of their significance in determining present and future species composition conditions. This paper aims to explain the qualitative and quantitative relationships between species diversity pattern and grain size （i.e. size of the sampling unit）, and species diversity pattern and sampling area, and to analyze species diversity variability on active sand dunes in the Horqin Sandy Land, northeastern Inner Mongolia, China. A 50 mx50 m sampling plot was selected on the windward slope, where the dominant species was annual herb Agriophyllum squarrosum. Species composition and abundance at five grain sizes were recorded, and the species-area curves were produced for thirteen grain sizes. The range of values for species abundance tended to increase with in- creasing grain size in the study area, whereas, generally, species richness did not follow this rule because of poor species richness on the windward slope of active sand dunes. However, the homogeneity of species richness in- creased significantly. With the increase in sampling area, species abundance increased linearly, but richness in- creased logarithmically. Furthermore, variograms showed that species diversity on the windward slope of active sand dunes was weakly anisotropic and the distribution pattern was random, according to the Moran Coefficient. The results also showed that species richness was low, with a random distribution pattern. This conflicts with the results of previous studies that showed spatial aggregation in lower richness in a sampling area within a community and inferred that the physical processes play a more important role in species diversity than distribution pattern on active sand dunes. Further research into different diversity patterns and mechanisms between active sand dunes and interdune lowlands should be conducted to better understand biodiversity conservation in sand dune fields.展开更多
Litter phosphorus （P） return is important to maintain the P cycle and balance in the sandy land of arid areas. In this study, we determined the loss and return of litter P in sand dune areas and elucidated their rel...Litter phosphorus （P） return is important to maintain the P cycle and balance in the sandy land of arid areas. In this study, we determined the loss and return of litter P in sand dune areas and elucidated their relation- ship. We investigated litter production and litter P amount, and simulated leaf litter moving dynamics to understand the relationships between the loss of litter P and the total litter P, and between the return of litter P and the total litter P in active （AD）, semi-stabilized （SSD） and stabilized （SD） dunes in Inner Mongolia, northeastern China. The vegetation litter P was 12.6, 94.5, and 201.6 mg P/m2 in AD, SSD, and SD, respectively. A significant movement and loss of leaf litter P with time occurred on the three types of sand dunes. As a result, the loss of P was 7.4, 46.9, and 69.8 mg P/m2 and the return of P was 5.5, 47.6, and 131.8 mg P/m2 in AD, SSD, and SD, respectively. The rela- tionship between both loss and return of P and total litter P in AD, SSD, and SD was revealed by linear regression. The slope of the regression line indicated the rate of loss or return of litter P. From AD to SD, the loss rate showed a declining slope （0.52, 0.32, and 0.17 for AD, SSD, and SD, respectively）, and the return rate showed a rising slope （0.48, 0.67, and 0.83 for AD, SSD, and SD, respectively）. The loss of litter P should be regarded in the local man- agement of vegetation and land in sand dune areas. Improved vegetation restoration measures are necessary to decrease litter P loss to maintain the stability of ecosystems in sand dune areas.展开更多
Soil seed banks can provide a mechanistic for understanding the recruitment dynamics and can inform conservation management of ecosystems. To investigate the contribution of soil seed banks to vegetation restoration i...Soil seed banks can provide a mechanistic for understanding the recruitment dynamics and can inform conservation management of ecosystems. To investigate the contribution of soil seed banks to vegetation restoration in moving sand dune systems, we compared seed structure and species similarity between soil seed banks and standing vegetation among moving sand dunes, ecotones and dune slacks in northeast China. Average seed density in dune slacks was greater than in ecotones or moving sand dunes. Seed density in the soil layer of 0-10 cm was greater than at 10-20 cm both in the moving sand dunes and the eco- tones, but seed densities were similar at depths of 10-20 and 20-30 cm in moving sand dunes. Moreover, the spatial autocorrelation of seed density on moving sand dunes was weak but was strong on the ecotones and dune slacks. The species in the soil seed bank of moving sand dune systems were nearly all annuals, and the low similarity was mainly due to the lack of perennial species that were common in standing vegetation. Consequently, vegetation restoration cannot mainly rely on the soil seed banks in the movingsand dunes and more attention should be paid to protection of the dune slacks because they are the main source of seed disperse and seedling recruitment in moving sand dune systems.展开更多
Water was a key factor restricting the plantation in sandy areas. Foliar δ^(13)C value regarded as an indicator of longterm water use efficiency(WUE) of plants was generally used to evaluate the adaptability of plant...Water was a key factor restricting the plantation in sandy areas. Foliar δ^(13)C value regarded as an indicator of longterm water use efficiency(WUE) of plants was generally used to evaluate the adaptability of plants to arid and semi-arid environment. In Horqin sandy land of China, the foliar δ^(13)C values of 114 species in 35 families naturally growing in the area, and 15 species of sand-fixing trees and shrubs were measured and analyzed in 2012. The results showed that 97 species in all 114 species were C_3 plants and only 17 species were C_4 plants. Most C_4 plants belonged to Gramineae family. The foliar δ^(13)C value of C_3 plants was between -25.000 and -31.075‰ with an average of-28.226‰, while those of C_4 plants between -12.578 and -16.334‰, with an average of -13.678‰. The δ^(13)C values of mature leaves collected in August were averagely 0.85‰ less than that of juvenile leaves collected in June. The foliar δ^(13)C values and WUE of 15 sand-fixing tree species in Horqin sandy land ranked in the order as: S.vulgaris >H.rhamnoides >C.ovata >P.mongolica >T.chinensis >R.typhina >S.matsudana >E.angustifolia >U.pumila >S.gordejevii >X.sorbifolia >C.microphylla >H.fruticosum >C.korshinskii >E.bungeanus.展开更多
Caragana microphylla is one of the key species for vegetation restoration in Horqin Sandy Land. Adopting field investigation and outdoor experiments,the microclimate effect of artificial C. microphylla communities wit...Caragana microphylla is one of the key species for vegetation restoration in Horqin Sandy Land. Adopting field investigation and outdoor experiments,the microclimate effect of artificial C. microphylla communities with different restoration years were studied by observing wind velocity,air temperature,relative humidity and soil temperature. The results show that:( 1) Caragana microphylla community has an obvious wind-breaking effect near ground surface. Compared with shifting dunes,the wind velocity in the 6-year-old and 11-year-old C. microphylla shrubs at the height of 30 cm separately decreases by 71. 9% and 76. 0%.( 2) Mean daily temperature in the 6-year-old and 11-yearold C. microphylla communities is 3. 7 ℃ and 4. 9 ℃ lower than in shifting dunes,respectively.( 3) The relative humidity of air in the Caragana microphylla shrubs is higher than in shifting dunes.( 4) Soil temperature in C. microphylla plantation is lower than in shifting dunes. These results are significant in further exploring material and energy exchange near surface layer of artificial vegetation in the extremely arid condition.展开更多
Spheroids and organoids have attracted significant attention as innovative models for disease modeling and drug screening.By employing diverse types of spheroids or organoids,it is feasible to establish microphysiolog...Spheroids and organoids have attracted significant attention as innovative models for disease modeling and drug screening.By employing diverse types of spheroids or organoids,it is feasible to establish microphysiological systems that enhance the precision of disease modeling and offer more dependable and comprehensive drug screening.High-throughput microphysiological systems that support optional,parallel testing of multiple drugs have promising applications in personalized medical treatment and drug research.However,establishing such a system is highly challenging and requires a multidisciplinary approach.This study introduces a dynamic Microphysiological System Chip Platform(MSCP)with multiple functional microstructures that encompass the mentioned advantages.We developed a high-throughput lung cancer spheroids model and an intestine-liverheart-lung cancer microphysiological system for conducting parallel testing on four anti-lung cancer drugs,demonstrating the feasibility of the MSCP.This microphysiological system combines microscale and macroscale biomimetics to enable a comprehensive assessment of drug efficacy and side effects.Moreover,the microphysiological system enables evaluation of the real pharmacological effect of drug molecules reaching the target lesion after absorption by normal organs through fluid-based physiological communication.The MSCP could serves as a valuable platform for microphysiological system research,making significant contributions to disease modeling,drug development,and personalized medical treatment.展开更多
Aims:Space-for-time substitution(SFT)is often used for vegetation status estimation during the recovery process of deserts.However,the evaluated accuracy of SFT remains uncertain.An eight-year located observation was ...Aims:Space-for-time substitution(SFT)is often used for vegetation status estimation during the recovery process of deserts.However,the evaluated accuracy of SFT remains uncertain.An eight-year located observation was used to assess the validity of SFT for vegetation state prediction.Methods:This study analyzed a chronosequence of Caragana microphylla Lam.plantings using the located observation method to test the accuracy of SFT for vegetation state prediction in the mobile sand dunes of the Horqin Sandy Land in northeastern China from July 2005 to June 2013.Important Findings:According to SFT,simple vegetation parameters(density,coverage and biomass)were found to be unstable,while sophisticated veg-etation parameters(species diversity and evenness)were relatively stable across the experimental treatments during the study period.Conversely,both the simple and sophisticated parameters were found to be relatively stable when tested using the located obser-vation method.Furthermore,most simple vegetation parameters slightly increased,while sophisticated parameters slightly decreased after eight years of field observations.Thus,long-term restoration management facilitated improvements in the simple parameters,but may have adversely impacted the sophisticated parameters in the post-restoration community.Our results suggest that sophisticated vegetation parameter states can be predicted by SFT,while simple vegetation parameter states are not well predicted by SFT.in conclusion,located observations or other effective evaluation methods must be employed to offset the deficiency of the SFT method for the prediction of vegetation parameters.展开更多
In recent decades,three-dimensional(3D)cancer cell models have attracted increasing interest in the field of drug screening due to their significant advantages in more accurate simulations of heterogeneous tumor behav...In recent decades,three-dimensional(3D)cancer cell models have attracted increasing interest in the field of drug screening due to their significant advantages in more accurate simulations of heterogeneous tumor behavior in vivo compared to two-dimensional models.Furthermore,drug sensitivity testing based on 3D cancer cell models can provide more reliable in vivo efficacy prediction.The gold standard fluorescence staining is hard to achieve real-time and label-free viability monitoring in 3D cancer cell models.In this study,a microgroove impedance sensor(MGIS)was specially developed for the dynamic and noninvasive monitoring of 3D cell viability.3D cancer cells were trapped in microgrooves with gold electrodes on opposite walls for in situ impedance measurement.The change in the number of live cells caused inversely proportional changes to the impedance magnitude of the entire cell/Matrigel construct and reflected the proliferation and apoptosis of the 3D cells.It was confirmed that the 3D cell viability detected by the MGIS was highly consistent with the standard live/dead staining by confocal microscope characterization.Furthermore,the accuracy of the MGIS was validated quantitatively using a 3D lung cancer model and sophisticated drug sensitivity testing.In addition,the parameters of the MGIS in the measurement experiments were optimized in detail using simulations and experimental validation.The results demonstrated that the MGIS coupled with 3D cell culture would be a promising platform to improve the efficiency and accuracy of cell-based anticancer drug screening in vitro.展开更多
2D MXene-Ti3C2Tx has demonstrated promising application prospects in various fields;however,it fails to function properly in biosensor setups due to restacking and anodic oxidation problems.To expand beyond these exis...2D MXene-Ti3C2Tx has demonstrated promising application prospects in various fields;however,it fails to function properly in biosensor setups due to restacking and anodic oxidation problems.To expand beyond these existing limitations,an effective strategy to for modifying the MXene by covalently grafting first-generation poly(amidoamine)dendrimers onto an MXene in situ(MXene@PAMAM)was reported herein.When used as a conjugated template,the MXene not only preserved the high conductivity but also conferred a specific 2D architecture and large specific surface areas for anchoring PAMAM.The PAMAM,an efficient spacer and stabilizer,simultaneously suppressed the substantial restacking and oxidation of the MXene,which endowed this hybrid with improved electrochemical performance compared to that of the bare MXene in terms of favorable conductivity and stability under anodic potential.Moreover,the massive amino terminals of PAMAM offer abundant active sites for adsorbing Au nanoparticles(AuNPs).The resulting 3D hierarchical nanoarchitecture,AuNPs/MXene@PAMAM,had advanced structural merits that led to its superior electrochemical performance in biosensing.As a proof of concept,this MXene@PAMAM-based nanobiosensing platform was applied to develop an immunosensor for detecting human cardiac troponin T(cTnT).A fast,sensitive,and highly selective response toward the target in the presence of a[Fe(CN)6]^(3-/4-)redox marker was realized,ensuring a wide detection of 0.1-1000 ng/mL with an LOD of 0.069 ng/mL.The sensor's signal only decreased by 4.38%after 3 weeks,demonstrating that it exhibited satisfactory stability and better results than previously reported MXene-based biosensors.This work has potential applicability in the bioanalysis of cTnT and other biomarkers and paves a new path for fabricating high-performance MXenes for biomedical applications and electrochemical engineering.展开更多
Annual plants are the main vegetation in arid and semi-arid desert regions.Because of their unique traits,they are the optimal experimental subjects for eco-logical studies.In this article,we summarize annual plants’...Annual plants are the main vegetation in arid and semi-arid desert regions.Because of their unique traits,they are the optimal experimental subjects for eco-logical studies.In this article,we summarize annual plants’seed germination strategies,seedling adaptability mechanism to environments,seed dispersal,and soil seed banks.We also discuss the biotic and abiotic factors affecting the composition and dynamics of annual plant populations and communities.Because annual plants have important ecological functions in desert vegetation systems,this study on annual plants will be of great benefit to the conservation and restoration of desert ecosystems,the rational utilization of resources,and the sustainable development of desert regions.展开更多
In this study,15 strains of Lactic acid bacteria(Allata et al.)and 6 strains of propionic acid bacteria(PAB)were firstly tested for their antifungal activity against three spoilage fungi,Aspergillus niger,Penicillium ...In this study,15 strains of Lactic acid bacteria(Allata et al.)and 6 strains of propionic acid bacteria(PAB)were firstly tested for their antifungal activity against three spoilage fungi,Aspergillus niger,Penicillium crustosum and Aspergillus flavus.Two strains of LAB and PAB were selected and assessed,alone or paired,for their abilities to inhibit the most resistant mold,Aspergillus niger.A mixed culture of P.freudenreichii D6 and L.plantarum L9 was found to be the most active and their optimal inoculum was 1×10^(8) and 1×10^(6) CFU/mL,respectively.Furthermore,the in situ antifungal effect of the mixed culture was evaluated against bakery product spoilage fungi.It was found that the growth of airborne fungi was delayed for up to 7 days.The cell number of L.plantarum L9 was slightly increased by the presence of P.freudenreichii D6.Quantification of three main acids(propionic,lactic and acetic acid)produced by the protective cultures suggested that acetic acid was mainly responsible for the antifungal activity.In conclusion,the mixed culture of P.freudenreichii and L.plantarum may be exploited as biopreservatives in bakery products.展开更多
Non-small cell lung cancer(NSCLC)is a leading cause of cancer mortality worldwide.Although epidermal growth factor receptor tyrosine kinase inhibitors(EGFR-TKIs)have dramatically improved the life expectancy of patien...Non-small cell lung cancer(NSCLC)is a leading cause of cancer mortality worldwide.Although epidermal growth factor receptor tyrosine kinase inhibitors(EGFR-TKIs)have dramatically improved the life expectancy of patients with NSCLC,concerns about TKI-induced cardiotoxicities have increased.AC0010,a novel third-generation TKI,was developed to overcome drug resistance induced by EGFR-T790M mutation.However,the cardiotoxicity of AC0010 remains unclear.To evaluate the efficacy and cardiotoxicity of AC0010,we designed a novel multifunctional biosensor by integrating microelectrodes(MEs)and interdigital electrodes(IDEs)to comprehensively evaluate cell viability,electrophysiological activity,and morphological changes(beating of cardiomyocytes).The multifunctional biosensor can monitor AC0010-induced NSCLC inhibition and cardiotoxicity in a quantitative,label-free,noninvasive,and real-time manner.AC0010 was found to significantly inhibit NCI-H1975(EGFR-L858R/T790M mutation),while weak inhibition was found for A549(wild-type EGFR).Negligible inhibition was found in the viabilities of HFF-1(normal fibroblasts)and cardiomyocytes.With the multifunctional biosensor,we found that 10μM AC0010 significantly affected the extracellular field potential(EFP)and mechanical beating of cardiomyocytes.The amplitude of EFP continuously decreased after AC0010 treatment,while the interval decreased first and then increased.We analyzed the change in the systole time(ST)and diastole time(DT)within a beating interval and found that the DT and DT/beating interval rate decreased within 1 h after AC0010 treatment.This result probably indicated that the relaxation of cardiomyocytes was insufficient,which may further aggravate the dysfunction.Here,we found that AC0010 significantly inhibited EGFR-mutant NSCLC cells and impaired cardiomyocyte function at low concentrations(10μM).This is the first study in which the risk of AC0010-induced cardiotoxicity was evaluated.In addition,novel multifunctional biosensors can comprehensively evaluate the antitumor efficacy and cardiotoxicity of drugs and candidate compounds.展开更多
基金supported by the National Key Basic Research Program of China (2011CB403204)the Natural Science Foundation of China (31000200)
文摘As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions modify organic carbon （SOC）, nitrogen （N） and phosphorus dynamics, bulk density and water-holding capacity and biological activities in soils, but little is known with regard to soil exchange properties. Variation in soil ex- changeable base cations was examined under C. microphylla plantations with an age sequence of 0, 5, 10, and 22 years in the Horqin Sandy Land, and at the depth of 0-10, 10-20, and 20-30 cm, respectively. C. microphylla has been planted on the non-vegetated sand dunes with similar physical-chemical soil properties. The results showed that exchangeable calcium （Ca）, magnesium （Mg）, and potassium （K）, and cation exchange capacity （CEC） were significantly increased, and Ca saturation tended to decrease, while Mg and K saturations were increased with the plantation years. No difference was observed for exchangeable sodium （Na） neither with plantation years nor at soil depths. Of all the base cations and soil layers, exchangeable K at the depth of 0-10 cm accumulated most quickly, and it increased by 1.76, 3.16, and 4.25 times, respectively after C. microphylla was planted for 5, 10, and 22 years. Exchangeable Ca, Mg, and K, and CEC were significantly （P〈0.001） and positively correlated with SOC, total N, pH and electrical conductivity （EC）. Soil pH and SOC are regarded as the main factors influencing the variation in ex- changeable cations, and the preferential absorption of cations by plants and different leaching rates of base cations that modify cation saturations under C. microphylla plantation. It is concluded that as a nitrogen-fixation species, C. microphylla plantation is beneficial to increasing exchangeable base cations and CEC in soils, and therefore can improve soil fertility and create favorable microenvironments for plants and creatures in the semi-arid sandy land ecosystems.
基金supported by the State Key Development Program for Basic Research (2013CB429905)the National Natural Science Foundation of China (41201052 and 41071187)the National Department Public Benefit Research Foundation (201004023)
文摘Understanding the effects of vegetation cover on seedling survival is helpful for promoting vegetation restoration in environmentally fragile zones. This study was conducted in the desertified, moving sand dunes of Horqin Sandy Land, Inner Mongolia, northeastern China. We hyphothesized that （1） seed density （i.e., number/m2） increases as vegetation cover increases, and （2） there will be more surviving seedlings in locations with higher vegetation covers. Total vegetation cover and initial densities of seeds, germinated seeds and surviving seedlings of Ulmus pumilia were evaluated under various vegetation covers in trying to clarify the effects of vegetation cover on the early stages of the plant life history. In agreement with the first hypothesis, initial seed densities were greater （P〈0.05） under higher vegetation covers. The relationship between vegetation cover and initial seed density was represented by a quadratic regression, where a threshold occurred with a vegetation cover of 36% （P〈0.05）. The higher total vegetation covers, however, did not result in increased densities of germinated seeds （P〉0.05）, which on average represented 16.7% of initial seed densities. Even more, three months after the study initiation, total vegetation covers were similar （P〉0.05） at all positions in the dunes, and they determined a similar number （P〉0.05） of surviving seedlings at those positions （i.e. the second hypothesis had to be rejected）. The mean number of seedlings that survived at all positions was only 4.5% of germinated seeds. The number of surviving elm seedlings （0 to 1.7 seedlings/m2） under various vegetations covers （12.2% to 20.8%） at all dune positions by late summer would most likely not contribute to vegetation restoration in the study area.
基金supported by the National Natural Science Foundation of China (40871247)the China National Twelfth Five-year-plan Key Project (2012BAD16B0302)
文摘Caragana microphylla Lam., a leguminous shrub species, plays an important role in revegetation in the degraded ecosystems of the Horqin Sandy Land, Northeastern China. Large areas planted with this shrub have been artificially established as sand binders for soil protection, which might change the composition of soil bacterial communities with the development of sand dune stabilization. In this paper, we investigated the diversity and composition of native soil bacterial communities in the C. microphylla plantation for sand fixation using polymerase chain reaction with denaturing gradient gel electrophoresis（PCR-DGGE） to understand the influence of this plantation on sandy soil ecosystem development. We collected soil samples from plantations with an age sequence of 0, 9, 16, and 26 years, as well as from the natural community, to identify the differences among soil bacterial communities. The result showed that bacterial abundance and community composition in the sandy land were affected by the age of the C. microphylla plantation. Moreover, bacterial diversity decreased with increasing plantation age, and the composition of the bacterial community in the 26-year plantation was similar to that in the natural community. Phylogenetic analysis of bands excised from the DGGE gels showed that members of alpha Proteobacterium, gamma Proteobacterium, Gemmatimonadetes and Chloroflexi were dominant in the sandy land. The stabilization of moving sand dune and development of sand-fixed plantation resulted in an increase of soil fertility, which could drive the structural evolvement of soil bacterial community, and it needs over 20 years for the soil bacterial community to form a stable structure, similar to the case for the natural vegetation.
基金financially supported by the National Natural Science Foundation of China (41071187 and 40701097)
文摘Two psammophile-dominated Artemisia semi-shrubs （A. wudanica and A. halodendron） and two annual Artemisia forbs （A. sieversiana and A. scoparia） bear significant ecological functions in Horqin Sandy Land, but systematical information on their achenes＇ germination is very limited. A set of studies were conducted to evaluate seed germination responses to storage periods and methods, different temperatures, lights conditions and sand burial depths, in order to determine inter-specific germination variation in the same genus and to explain how the species adapt to its microhabitat. Fresh achenes of A. wudanica, A. halodendron and A. sieversiana showed high germination capacities, but those of A. scoparia had obvious innate dormancy, which could be broken by chilling and dry storage, especially long-term dry storage. Achene germination of the two semi-shrubs preferred lower temperature fluctuation （10 to 22℃） and was not sensitive to light. But the two annuals preferred higher temperature fluctuation （34 to 22℃） and strong light for their achene germination. These four Artemisia species showed similar responses to sand burial, i.e. soil surface was most favorable for seedling emergence, and the deeper the sand burial, the fewer the seedling emergence. For the two semi-shrubs, their microhabitats are sand dunes with high temperature and intense light, which are not favorable for germination and seedling survival. Only rainfall contributes to temporary decrease of temperature and then triggers germination. We deduced that germination is not the main but a supplementary repro- ductive mode for the two semi-shrubs in sand dunes. For the two annuals, achene germination is the only reproductive mode, but different responses have been developed for microhabitat adaptation. For A. sieversiana, high germination capacities in wide temperature ranges and all light conditions could improve its competition and advancement in the wettest microhabitats. For A. scoparia, obvious innate dormancy of fresh achenes and germination inhabitation under unfavorable conditions are important adaptation to environmental disturbances.
基金funded by the National Natural Science Foundation of China (41071187)the State Forestry Administration Industry Special Project (201004023)
文摘Species richness and abundance are two important species diversity variables that have attracted particular attention because of their significance in determining present and future species composition conditions. This paper aims to explain the qualitative and quantitative relationships between species diversity pattern and grain size （i.e. size of the sampling unit）, and species diversity pattern and sampling area, and to analyze species diversity variability on active sand dunes in the Horqin Sandy Land, northeastern Inner Mongolia, China. A 50 mx50 m sampling plot was selected on the windward slope, where the dominant species was annual herb Agriophyllum squarrosum. Species composition and abundance at five grain sizes were recorded, and the species-area curves were produced for thirteen grain sizes. The range of values for species abundance tended to increase with in- creasing grain size in the study area, whereas, generally, species richness did not follow this rule because of poor species richness on the windward slope of active sand dunes. However, the homogeneity of species richness in- creased significantly. With the increase in sampling area, species abundance increased linearly, but richness in- creased logarithmically. Furthermore, variograms showed that species diversity on the windward slope of active sand dunes was weakly anisotropic and the distribution pattern was random, according to the Moran Coefficient. The results also showed that species richness was low, with a random distribution pattern. This conflicts with the results of previous studies that showed spatial aggregation in lower richness in a sampling area within a community and inferred that the physical processes play a more important role in species diversity than distribution pattern on active sand dunes. Further research into different diversity patterns and mechanisms between active sand dunes and interdune lowlands should be conducted to better understand biodiversity conservation in sand dune fields.
基金supported by the National Natural Science Foundation of China(30800163)
文摘Litter phosphorus （P） return is important to maintain the P cycle and balance in the sandy land of arid areas. In this study, we determined the loss and return of litter P in sand dune areas and elucidated their relation- ship. We investigated litter production and litter P amount, and simulated leaf litter moving dynamics to understand the relationships between the loss of litter P and the total litter P, and between the return of litter P and the total litter P in active （AD）, semi-stabilized （SSD） and stabilized （SD） dunes in Inner Mongolia, northeastern China. The vegetation litter P was 12.6, 94.5, and 201.6 mg P/m2 in AD, SSD, and SD, respectively. A significant movement and loss of leaf litter P with time occurred on the three types of sand dunes. As a result, the loss of P was 7.4, 46.9, and 69.8 mg P/m2 and the return of P was 5.5, 47.6, and 131.8 mg P/m2 in AD, SSD, and SD, respectively. The rela- tionship between both loss and return of P and total litter P in AD, SSD, and SD was revealed by linear regression. The slope of the regression line indicated the rate of loss or return of litter P. From AD to SD, the loss rate showed a declining slope （0.52, 0.32, and 0.17 for AD, SSD, and SD, respectively）, and the return rate showed a rising slope （0.48, 0.67, and 0.83 for AD, SSD, and SD, respectively）. The loss of litter P should be regarded in the local man- agement of vegetation and land in sand dune areas. Improved vegetation restoration measures are necessary to decrease litter P loss to maintain the stability of ecosystems in sand dune areas.
基金supported by National Natural Science Foundation of China(41271115)
文摘Soil seed banks can provide a mechanistic for understanding the recruitment dynamics and can inform conservation management of ecosystems. To investigate the contribution of soil seed banks to vegetation restoration in moving sand dune systems, we compared seed structure and species similarity between soil seed banks and standing vegetation among moving sand dunes, ecotones and dune slacks in northeast China. Average seed density in dune slacks was greater than in ecotones or moving sand dunes. Seed density in the soil layer of 0-10 cm was greater than at 10-20 cm both in the moving sand dunes and the eco- tones, but seed densities were similar at depths of 10-20 and 20-30 cm in moving sand dunes. Moreover, the spatial autocorrelation of seed density on moving sand dunes was weak but was strong on the ecotones and dune slacks. The species in the soil seed bank of moving sand dune systems were nearly all annuals, and the low similarity was mainly due to the lack of perennial species that were common in standing vegetation. Consequently, vegetation restoration cannot mainly rely on the soil seed banks in the movingsand dunes and more attention should be paid to protection of the dune slacks because they are the main source of seed disperse and seedling recruitment in moving sand dune systems.
基金Supported by the Scientific Research Project of Hebei Higher Education(QN2015306)National Key Technology Research and Development Program of China during the 12th Five-Year Plan(2012BAD16B0302)
文摘Water was a key factor restricting the plantation in sandy areas. Foliar δ^(13)C value regarded as an indicator of longterm water use efficiency(WUE) of plants was generally used to evaluate the adaptability of plants to arid and semi-arid environment. In Horqin sandy land of China, the foliar δ^(13)C values of 114 species in 35 families naturally growing in the area, and 15 species of sand-fixing trees and shrubs were measured and analyzed in 2012. The results showed that 97 species in all 114 species were C_3 plants and only 17 species were C_4 plants. Most C_4 plants belonged to Gramineae family. The foliar δ^(13)C value of C_3 plants was between -25.000 and -31.075‰ with an average of-28.226‰, while those of C_4 plants between -12.578 and -16.334‰, with an average of -13.678‰. The δ^(13)C values of mature leaves collected in August were averagely 0.85‰ less than that of juvenile leaves collected in June. The foliar δ^(13)C values and WUE of 15 sand-fixing tree species in Horqin sandy land ranked in the order as: S.vulgaris >H.rhamnoides >C.ovata >P.mongolica >T.chinensis >R.typhina >S.matsudana >E.angustifolia >U.pumila >S.gordejevii >X.sorbifolia >C.microphylla >H.fruticosum >C.korshinskii >E.bungeanus.
基金Supported by Project of National Natural Science Foundation(71203057,41271115,41071187)Young Scholar Project of Humanities and Social Science Foundation of Ministry of Education(11YJCZH056)Ph.D Foundation Project of Henan Polytechnic University(B2011-017)
文摘Caragana microphylla is one of the key species for vegetation restoration in Horqin Sandy Land. Adopting field investigation and outdoor experiments,the microclimate effect of artificial C. microphylla communities with different restoration years were studied by observing wind velocity,air temperature,relative humidity and soil temperature. The results show that:( 1) Caragana microphylla community has an obvious wind-breaking effect near ground surface. Compared with shifting dunes,the wind velocity in the 6-year-old and 11-year-old C. microphylla shrubs at the height of 30 cm separately decreases by 71. 9% and 76. 0%.( 2) Mean daily temperature in the 6-year-old and 11-yearold C. microphylla communities is 3. 7 ℃ and 4. 9 ℃ lower than in shifting dunes,respectively.( 3) The relative humidity of air in the Caragana microphylla shrubs is higher than in shifting dunes.( 4) Soil temperature in C. microphylla plantation is lower than in shifting dunes. These results are significant in further exploring material and energy exchange near surface layer of artificial vegetation in the extremely arid condition.
基金funded by the National Key Research and Development Program of China(No.2021YFF1200803)National Natural Science Foundation of China(No.62120106004,61901412,62271443)and China Postdoctoral Science Foundation Funded Project(2022M712783).
文摘Spheroids and organoids have attracted significant attention as innovative models for disease modeling and drug screening.By employing diverse types of spheroids or organoids,it is feasible to establish microphysiological systems that enhance the precision of disease modeling and offer more dependable and comprehensive drug screening.High-throughput microphysiological systems that support optional,parallel testing of multiple drugs have promising applications in personalized medical treatment and drug research.However,establishing such a system is highly challenging and requires a multidisciplinary approach.This study introduces a dynamic Microphysiological System Chip Platform(MSCP)with multiple functional microstructures that encompass the mentioned advantages.We developed a high-throughput lung cancer spheroids model and an intestine-liverheart-lung cancer microphysiological system for conducting parallel testing on four anti-lung cancer drugs,demonstrating the feasibility of the MSCP.This microphysiological system combines microscale and macroscale biomimetics to enable a comprehensive assessment of drug efficacy and side effects.Moreover,the microphysiological system enables evaluation of the real pharmacological effect of drug molecules reaching the target lesion after absorption by normal organs through fluid-based physiological communication.The MSCP could serves as a valuable platform for microphysiological system research,making significant contributions to disease modeling,drug development,and personalized medical treatment.
基金This work was supported by the National Key Research and Development Program of China(2016YFC0500803).
文摘Aims:Space-for-time substitution(SFT)is often used for vegetation status estimation during the recovery process of deserts.However,the evaluated accuracy of SFT remains uncertain.An eight-year located observation was used to assess the validity of SFT for vegetation state prediction.Methods:This study analyzed a chronosequence of Caragana microphylla Lam.plantings using the located observation method to test the accuracy of SFT for vegetation state prediction in the mobile sand dunes of the Horqin Sandy Land in northeastern China from July 2005 to June 2013.Important Findings:According to SFT,simple vegetation parameters(density,coverage and biomass)were found to be unstable,while sophisticated veg-etation parameters(species diversity and evenness)were relatively stable across the experimental treatments during the study period.Conversely,both the simple and sophisticated parameters were found to be relatively stable when tested using the located obser-vation method.Furthermore,most simple vegetation parameters slightly increased,while sophisticated parameters slightly decreased after eight years of field observations.Thus,long-term restoration management facilitated improvements in the simple parameters,but may have adversely impacted the sophisticated parameters in the post-restoration community.Our results suggest that sophisticated vegetation parameter states can be predicted by SFT,while simple vegetation parameter states are not well predicted by SFT.in conclusion,located observations or other effective evaluation methods must be employed to offset the deficiency of the SFT method for the prediction of vegetation parameters.
基金This work was supported by National Natural Science Foundation of China(grant no.31627801)the National Natural Science Foundation of China(nos.81811530116,31800826,and 61901412)Fundamental Research Funds for the Central Universities(grant no.2018QNA5018,2018FZA5018).
文摘In recent decades,three-dimensional(3D)cancer cell models have attracted increasing interest in the field of drug screening due to their significant advantages in more accurate simulations of heterogeneous tumor behavior in vivo compared to two-dimensional models.Furthermore,drug sensitivity testing based on 3D cancer cell models can provide more reliable in vivo efficacy prediction.The gold standard fluorescence staining is hard to achieve real-time and label-free viability monitoring in 3D cancer cell models.In this study,a microgroove impedance sensor(MGIS)was specially developed for the dynamic and noninvasive monitoring of 3D cell viability.3D cancer cells were trapped in microgrooves with gold electrodes on opposite walls for in situ impedance measurement.The change in the number of live cells caused inversely proportional changes to the impedance magnitude of the entire cell/Matrigel construct and reflected the proliferation and apoptosis of the 3D cells.It was confirmed that the 3D cell viability detected by the MGIS was highly consistent with the standard live/dead staining by confocal microscope characterization.Furthermore,the accuracy of the MGIS was validated quantitatively using a 3D lung cancer model and sophisticated drug sensitivity testing.In addition,the parameters of the MGIS in the measurement experiments were optimized in detail using simulations and experimental validation.The results demonstrated that the MGIS coupled with 3D cell culture would be a promising platform to improve the efficiency and accuracy of cell-based anticancer drug screening in vitro.
基金supported by the National Natural Science Foundation of China(Grant Nos.31627801,61901412)the Science and Technology Project of Zhejiang Province(Grant Nos.2019C03066,LGF19H180022).
文摘2D MXene-Ti3C2Tx has demonstrated promising application prospects in various fields;however,it fails to function properly in biosensor setups due to restacking and anodic oxidation problems.To expand beyond these existing limitations,an effective strategy to for modifying the MXene by covalently grafting first-generation poly(amidoamine)dendrimers onto an MXene in situ(MXene@PAMAM)was reported herein.When used as a conjugated template,the MXene not only preserved the high conductivity but also conferred a specific 2D architecture and large specific surface areas for anchoring PAMAM.The PAMAM,an efficient spacer and stabilizer,simultaneously suppressed the substantial restacking and oxidation of the MXene,which endowed this hybrid with improved electrochemical performance compared to that of the bare MXene in terms of favorable conductivity and stability under anodic potential.Moreover,the massive amino terminals of PAMAM offer abundant active sites for adsorbing Au nanoparticles(AuNPs).The resulting 3D hierarchical nanoarchitecture,AuNPs/MXene@PAMAM,had advanced structural merits that led to its superior electrochemical performance in biosensing.As a proof of concept,this MXene@PAMAM-based nanobiosensing platform was applied to develop an immunosensor for detecting human cardiac troponin T(cTnT).A fast,sensitive,and highly selective response toward the target in the presence of a[Fe(CN)6]^(3-/4-)redox marker was realized,ensuring a wide detection of 0.1-1000 ng/mL with an LOD of 0.069 ng/mL.The sensor's signal only decreased by 4.38%after 3 weeks,demonstrating that it exhibited satisfactory stability and better results than previously reported MXene-based biosensors.This work has potential applicability in the bioanalysis of cTnT and other biomarkers and paves a new path for fabricating high-performance MXenes for biomedical applications and electrochemical engineering.
基金The project was supported by the National Science and Technology Tackle of China(No.2005BA517A08)Desert Monitor Programme of State Forestry Administration,China(No.00-08-05).
文摘Annual plants are the main vegetation in arid and semi-arid desert regions.Because of their unique traits,they are the optimal experimental subjects for eco-logical studies.In this article,we summarize annual plants’seed germination strategies,seedling adaptability mechanism to environments,seed dispersal,and soil seed banks.We also discuss the biotic and abiotic factors affecting the composition and dynamics of annual plant populations and communities.Because annual plants have important ecological functions in desert vegetation systems,this study on annual plants will be of great benefit to the conservation and restoration of desert ecosystems,the rational utilization of resources,and the sustainable development of desert regions.
文摘In this study,15 strains of Lactic acid bacteria(Allata et al.)and 6 strains of propionic acid bacteria(PAB)were firstly tested for their antifungal activity against three spoilage fungi,Aspergillus niger,Penicillium crustosum and Aspergillus flavus.Two strains of LAB and PAB were selected and assessed,alone or paired,for their abilities to inhibit the most resistant mold,Aspergillus niger.A mixed culture of P.freudenreichii D6 and L.plantarum L9 was found to be the most active and their optimal inoculum was 1×10^(8) and 1×10^(6) CFU/mL,respectively.Furthermore,the in situ antifungal effect of the mixed culture was evaluated against bakery product spoilage fungi.It was found that the growth of airborne fungi was delayed for up to 7 days.The cell number of L.plantarum L9 was slightly increased by the presence of P.freudenreichii D6.Quantification of three main acids(propionic,lactic and acetic acid)produced by the protective cultures suggested that acetic acid was mainly responsible for the antifungal activity.In conclusion,the mixed culture of P.freudenreichii and L.plantarum may be exploited as biopreservatives in bakery products.
基金This study was supported by the National Natural Science Foundation of China(Grant no.62120106004)the China Postdoctoral Science Foundation(Grant no.2022M712783,BX2021265,2021M702859).
文摘Non-small cell lung cancer(NSCLC)is a leading cause of cancer mortality worldwide.Although epidermal growth factor receptor tyrosine kinase inhibitors(EGFR-TKIs)have dramatically improved the life expectancy of patients with NSCLC,concerns about TKI-induced cardiotoxicities have increased.AC0010,a novel third-generation TKI,was developed to overcome drug resistance induced by EGFR-T790M mutation.However,the cardiotoxicity of AC0010 remains unclear.To evaluate the efficacy and cardiotoxicity of AC0010,we designed a novel multifunctional biosensor by integrating microelectrodes(MEs)and interdigital electrodes(IDEs)to comprehensively evaluate cell viability,electrophysiological activity,and morphological changes(beating of cardiomyocytes).The multifunctional biosensor can monitor AC0010-induced NSCLC inhibition and cardiotoxicity in a quantitative,label-free,noninvasive,and real-time manner.AC0010 was found to significantly inhibit NCI-H1975(EGFR-L858R/T790M mutation),while weak inhibition was found for A549(wild-type EGFR).Negligible inhibition was found in the viabilities of HFF-1(normal fibroblasts)and cardiomyocytes.With the multifunctional biosensor,we found that 10μM AC0010 significantly affected the extracellular field potential(EFP)and mechanical beating of cardiomyocytes.The amplitude of EFP continuously decreased after AC0010 treatment,while the interval decreased first and then increased.We analyzed the change in the systole time(ST)and diastole time(DT)within a beating interval and found that the DT and DT/beating interval rate decreased within 1 h after AC0010 treatment.This result probably indicated that the relaxation of cardiomyocytes was insufficient,which may further aggravate the dysfunction.Here,we found that AC0010 significantly inhibited EGFR-mutant NSCLC cells and impaired cardiomyocyte function at low concentrations(10μM).This is the first study in which the risk of AC0010-induced cardiotoxicity was evaluated.In addition,novel multifunctional biosensors can comprehensively evaluate the antitumor efficacy and cardiotoxicity of drugs and candidate compounds.
