Fungi play an important role in dying wastewater treatment.In this work,the mycelia of Lactarius deliciosus exhibited an excellent capacity in decolorizing coomassie brilliant blue(CBB).The results demonstrated that t...Fungi play an important role in dying wastewater treatment.In this work,the mycelia of Lactarius deliciosus exhibited an excellent capacity in decolorizing coomassie brilliant blue(CBB).The results demonstrated that the mycelia could treat CBB with high concentrations over a broad range of pH and temperature.The decolorization rate of 99.19%and the removal rate of 16.31 mg·L^(‒1)·h were realized.The mycelia could be recycled from decolorizing process for 19 times,indicating a good re-usability.It verified that the lignin peroxidase(121.65 U·L^(‒1))and manganese peroxidase(36.77 U·L^(‒1))were involved in the degradation and decolorization process of CBB.Toxicity assessments indicated the seed germination rate was up to 82.22%while inhibition to Escherichia coli decreased dramatically and no significant effect on Caenorhabditis elegans growth was found.The removal of CBB was a synergistic process accomplished by adsorption and biodegradation.The mycelia could be used for eco-friendly CBB treatment.展开更多
Changbai Mountain,central in the distribution of Pinus koraiensis,supports a virgin Korean pine forest with vertical gradient distribution.Soil extracellular enzyme activity(EEA) and enzyme stoichiometry(ES) are relia...Changbai Mountain,central in the distribution of Pinus koraiensis,supports a virgin Korean pine forest with vertical gradient distribution.Soil extracellular enzyme activity(EEA) and enzyme stoichiometry(ES) are reliable indicators of the energy and nutrients utilized by microbial communities and of soil nutrient changes.We measured four representative soil EEAs(sucrase,cellulase,urease,acid phosphatase) at two soil layers(A:0-5 cm and B:5-10 cm)beneath Korean pine forest at five elevations on Changbai Mountain during growing season.The vertical and seasonal variations of EEAs were analyzed by soil enzyme stoichiometry to quantify the role of soil microorganism in the nutrient cycling process.The activities of four soil extracellular enzymes and the ratios of enzyme activity to soil microbial biomass carbon(EA/SMBC) did not vary with elevation.The first partition point of multiple regression trees was in September,and the second branch was split by elevation.Seasonal change had more influence on soil enzyme activity(A layer:75.6%;B layer:71.3%) than did change in elevation(A layer:7.8%;B layer:7.5%).Over one entire growing season,both vector length and vector angle were unchanged by elevation,but varied significantly by month.Among the soil physicochemical factors,available phosphorus and pH were the main factors affecting the four soil EE As.The ratio of basal area of the coniferous tree to broad-leaved tree species(S_(con)/S_(br)),soil microbial biomass carbon(MBC) and nitrogen(MBN) influenced the four soil EE As.The results of vector analysis revealed that C and N sources were generally sufficient,but P was limiting(vector angle> 45°).The vector angle for September was significantly higher than for other months.This result verified that phosphorus was the limiting factor affecting soil microorganism function in nutrient metabolism and cycling.Soil enzyme stoichiometry proved to be an efficient index for quantifying soil microorganismmediated nutrient cycling in the Korean pine ecosystem.展开更多
Although returning crop residue to fields is a recommended measure for improving soil carbon(C)stocks in agroecosystems,the response of newly formed soil C(NFC)to the integrated supply of residue and nutrients and the...Although returning crop residue to fields is a recommended measure for improving soil carbon(C)stocks in agroecosystems,the response of newly formed soil C(NFC)to the integrated supply of residue and nutrients and the microbial mechanisms involved in NFC are not fully understood.Therefore,an 84-day incubation experiment was conducted to ascertain the microbial mechanisms that underpin the NFC response to inputs of residue and nitrogen(N),phosphorus(P),and sulfur(S)in two black(Phaeozem)soils from experimental plots at Gongzhuling,Jilin Province and Hailun,Heilongjiang Province,China.The results showed that adding residue alone accelerated microbial nutrient mining,which was supported by decreases of 8^(-1)6%in the ratios of C:N and C:P enzyme activities,relative to soils with nutrient inputs.The NFC amounts increased from 1156 to 1722 mg kg^(−1) in Gongzhuling soil and from 725 to 1067 mg kg^(−1) in Hailun soil as the levels of nutrient supplementation increased.Boosted regression tree analysis suggested thatβ-glucosidase(BG),acid phosphatase(AP),microbial biomass C(MBC),and Acidobacteria accounted for 27.8,18.5,14.7,and 8.1%,respectively,of the NFC in Gongzhuling soil and for 25.9,29.5,10.1,and 13.9%,respectively,of the NFC in Hailun soil.Path analysis determined that Acidobacteria positively influenced NFC both directly and indirectly by regulating BG,AP,and MBC,in which MBC acquisition was regulated more by AP.The amount of NFC was lower in Hailun soil than in Gongzhuling soil and was directly affected by AP,indicating the importance of soil properties such as SOC and pH in determining NFC.Overall,our results reveal the response of NFC to supplementation by N,P,and S,which depends on Acidobacteria and Proteobacteria,and their investment in BG and AP in residue-amended soil.展开更多
BACKGROUND Extracellular matrix(ECM)remodeling and stiffening,which are correlated with tumor malignancy,drives tumor development.However,the relationship between ECM remodeling and rat experimental model of 1,2-dimet...BACKGROUND Extracellular matrix(ECM)remodeling and stiffening,which are correlated with tumor malignancy,drives tumor development.However,the relationship between ECM remodeling and rat experimental model of 1,2-dimethylhyrazine(DMH)-induced colorectal cancer(CRC)imposed by cold and capsaicin exposure remains unclear.AIM To explore the effects of cold exposure and capsaicin on ECM remodeling and ECM enzymes in DMH-induced CRC.METHODS For histopathological analysis,the sections of colon tissues were stained with hematoxylin and eosin,Masson’s trichrome,Picrosirius red,and Weigert’s Resorcin-Fuchsin to observe the remodeling of collagen and elastin.Additionally,the protein expression level of type I collagen(COL I),type 3 collagen(COL III0,elastin,matrix metalloproteinase(MMP)1,MMP2,MMP9,and tissue-specific matrix metalloproteinase 1(TIMP1)was assessed by immunohistochemistry.The messenger RNA(mRNA)levels of COL I,COL III,elastin,and lysyl oxidase-like-2(LOXL2)in the colon tissues of rats was measured by reverse-transcriptase quantitative polymerase chain reaction.RESULTS Although no differences were observed in the proportion of adenomas,a trend towards the increase of invasive tumors was observed in the cold and capsaicin group.The cold exposure group had a metastasis rate compared with the other groups.Additionally,abnormal accumulation of both collagen and elastin was observed in the cold exposure and capsaicin group.Specifically,collagen quantitative analysis showed increased length,width,angle,and straightness compared with the DMH group.Collagen deposition and straightness were significantly increased in the cold exposure group compared with the capsaicin group.Cold exposure and capsaicin significantly increased the protein levels of COL I,elastin,and LOXL2 along with increases in their mRNA levels in the colon tissues compared with the DMH group,while COL III did not show a significant difference.Furthermore,in immunohistochemical evaluations,MMP1,MMP2,MMP9,and TIMP1 staining increased in the cold exposure and capsaicin group compared with the DMH group.CONCLUSION These results suggest that chronic cold and capsaicin exposure further increased the deposition of collagen and elastin in the colonic tissue.Increased COL I and elastin mRNA and protein levels expression may account for the enhanced ECM remodel and stiffness variations of colon tissue.The upregulated expression of the LOXL2 and physiological imbalance between MMP/TIMP activation and deactivation could contribute to the progression of the CRC resulting from cold and capsaicin exposure.展开更多
The high water content of municipal solid waste(MSW)will reduce the effciency of mechanical sorting,consequently unfavorable for beneficial utilization.In this study,a combined hydrolytic-aerobic biodrying technology ...The high water content of municipal solid waste(MSW)will reduce the effciency of mechanical sorting,consequently unfavorable for beneficial utilization.In this study,a combined hydrolytic-aerobic biodrying technology was introduced to remove water from MSW.The total water removals were proved to depend on the ventilation frequency and the temporal span in the hydrolytic stage. The ventilation frequency of 6 times/d was preferable in the hydrolytic stage.The hydrolytic span should not be prolonged more than 4 d.At this optimal scenario,the final water content was 50.5%reduced from the initial water content of 72.0%,presenting a high water removal effciency up to 78.5%.A positive correlation was observed between the organics losses and the water losses in both hydrolytic and aerobic stages(R=0.944,p<0.01).The evolutions of extracellular enzyme activities were shown to be consistent with the organics losses.展开更多
Mangroves are one of the most ecologically sensitive ecosystems to global climate change,which have cascading impacts on soil carbon(C),nitrogen(N)and phosphorus(P)cycling.Moreover,mangroves are experiencing increasin...Mangroves are one of the most ecologically sensitive ecosystems to global climate change,which have cascading impacts on soil carbon(C),nitrogen(N)and phosphorus(P)cycling.Moreover,mangroves are experiencing increasing N and P loadings and reduced oxygen availability due to intensified climate change and human activities.However,both direct and interactive effects of these perturbations on microbially mediated soil C,N and P cycling are poorly understood.Here,we simultaneously investigated the effects of N and P loadings and reduced oxygen on microbial biomass,microbial respiration,and extracellular enzyme activities(EEAs)in mangrove soils.We calculated the microbial metabolic quotient(qCO_(2)),which is regarded as a useful inverse metric of microbial C use efficiency(CUE).Our results show that reduced oxygen significantly increases both qCO_(2) and microbial specific EEAs(enzyme activity per unit of microbial biomass)for C-,N-and P-acquisition regardless of N or P loadings.Furthermore,we found that qCO_(2) positively correlated with microbial specific EEAs under reduced oxygen,whereas no clear relationship was detected under ambient oxygen.These results suggest that reduced oxygen increases microbial specific EEAs at the expense of increasing microbial respiration per unit biomass,indicating higher energy cost per unit enzyme production.展开更多
The proportion of organic matter and mineral composition are important factors determining the formation and type of non-extractable residues(NERs) of pesticides in soil. In this study, we investigated the enantiosele...The proportion of organic matter and mineral composition are important factors determining the formation and type of non-extractable residues(NERs) of pesticides in soil. In this study, we investigated the enantioselectivity in degradation and NER formation of the chiral fungicide metalaxyl in soil particle size fractions(silt and clay). Microbial and extracellular enzyme activities during these processes were monitored in incubation of silt and clay samples isolated from sterilized and non-sterilized soil samples collected from a long-term agricultural field experimental site in Ultuna, Sweden. The temporal influence on the fate of the fungicide was noted by short-term(10-d) and long-term(92-d) incubations. Besides the acquisition of quantitative data with gas chromatography-mass spectrometry(GC/MS), stereoselective analyses were performed with chiral GC/MS. Quantitative results pointed to a higher metabolism rate of the pesticide through microbial activity than through extracellular enzyme activity. This was also confirmed by the enantioselective depletion of R-metalaxyl and the subsequent formation of R-metalaxyl acid in microbially active samples from non-sterilized soil. The silt fraction containing a high amount of organic matter exhibited a significant hydrolyzable proportion of metalaxyl NERs that was releasable under alkaline conditions. On the contrary, the clay fraction showed an enhanced affinity for covalently bound residues. Based on our results, we recommend differentiating between reversibly and irreversibly bound proportions of pesticides in persistence and environmental risk assessment because the reversible fraction contained potentially bioavailable amounts of residues that may be released under natural conditions.展开更多
Wallemia comprises air-and food-borne,mycotoxigenic contaminants including the halophilic W.ichthyophaga,xerotolerant W.sebi and xerophilic W.muriae.Wallemia isolates are easily overlooked and only a comparably small ...Wallemia comprises air-and food-borne,mycotoxigenic contaminants including the halophilic W.ichthyophaga,xerotolerant W.sebi and xerophilic W.muriae.Wallemia isolates are easily overlooked and only a comparably small number of strains have been deposited in culture collections so far.In order to better understand the natural distribution of Wallemia spp.and to encounter their natural habitats,we tested more than 300 low-water-activity substrates and 30 air samples from a wide geographical coverage.We isolated more than 150 new Wallemia strains.Wallemia sebi and W.muriae were isolated mostly from hypersaline water,low-water-activity foods,plant materials and indoor.Wallemia muriae is the dominant Wallemia species in the air of natural and human influenced environments in Europe.New isolates of W.ichthyophaga were obtained from hypersaline environments such as brine,salt crystals,salty foods and MgCl_(2)-rich bitterns,and from the air of hay barns in Denmark.Five halotolerant strains were recognised as a hitherto un-described species Wallemia hederae,the phylogenetic sister of the halophilic W.ichthyophaga.Wallemia spp.show in-vitro growth on media that contain the chaotropic salt MgCl_(2).Wallemia ichthyophaga can grow in liquid medium enriched with 2 M MgCl_(2).Never before has a microorganism been grown on comparably high MgCl_(2) concentrations.Tests of the activity of a wide range of extracellular enzymes in the presence of NaCl also suggested that Wallemia iswell-adapted to substrates with a reduced water activity.展开更多
Soil microorganisms play a key role in soil organic matter dynamics, nutrient cycling, and soil fertility maintenance in forest ecosystems, and they are influenced by stand age and soil depth. However, few studies hav...Soil microorganisms play a key role in soil organic matter dynamics, nutrient cycling, and soil fertility maintenance in forest ecosystems, and they are influenced by stand age and soil depth. However, few studies have simultaneously considered these two factors. In this study, we measured soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil basal respiration (SBR) rate, and potential extracellular enzyme activity (EEA) in soil to a depth of 60 cm under 10-, 30-, and 40-year-old Scots pine (Pinus sylvestris var. mongolica) stands (Y10, Y30, and Y40, respectively) in plantations in northern China in 2011. Soil water content (SWC), soil pH, soil organic carbon (SOC), and soil total nitrogen (STN) were also measured to explore their effects on soil microbial indices across different stand ages and soil depths. Our results showed that SMBC, SMBN, and the SBR rate were generally higher for the Y30 stand than for the Y10 and Y40 stands. Potential EEA, except forα-glucosidase, decreased significantly with increasing stand age. Soil organic carbon,STN, SWC, and soil pH explained 67%of the variation in soil microbial attributes among the three stand ages. For the same stand age, soil microbial biomass and the SBR rate decreased with soil depth. Lower microbial biomass, lower SBR rate, and lower EEA for the mature Y40 stand indicate lower substrate availability for soil microorganisms, lower soil quality, and lower microbial adaptability to the environment. Our results suggest that changes in soil quality with stand age should be considered when determining the optimum rotation length of plantations and the best management practices for afforestation programs.展开更多
Aims Plants generally respond to nitrogen(N)fertilization with increased growth,but N addition can also suppress rhizosphere effects,which consequently alters soil processes.We quantified the influence of N addition o...Aims Plants generally respond to nitrogen(N)fertilization with increased growth,but N addition can also suppress rhizosphere effects,which consequently alters soil processes.We quantified the influence of N addition on rhizosphere effects of two C4 grasses:smooth crabgrass(Digitaria ischaemum)and bermudagrass(Cynodon dactylon).Methods Plants were grown in nutrient-poor soil for 80 days with either 20 or 120μg NH4No3-N g dry soil−1.N mineralization rates,microbial biomass,extracellular enzyme activities and bacterial community structure were measured on both rhizosphere and bulk(unplanted)soils after plant harvest.Important Findings Fertilization showed nominal differences in net N mineralization,extracellular enzyme activity and microbial biomass between the rhizosphere and bulk soils,indicating minimal influence of N on rhizosphere effects.Instead,the presence of plant roots showed the strongest impact(up to 80%)on rates of net N mineralization and activities of three soil enzymes indicative of N release from organic matter.Principal component analysis of terminal restriction fragment length polymorphism(t-rFlP)also reflected these trends by highlighting the importance of plant roots in structuring the soil bacterial community,followed by plant species and N fertilization(to a minor extent).overall,the results indicate minor contributions of short-term N fertilization to changes in the magnitude of rhizos-phere effects for both grass species.展开更多
Microbial biomass and extracellular enzyme activities control the rate of soil organic carbon decomposition,thereby affecting soil carbon pool.However,seasonal dynamics of soil microbial properties at different depths...Microbial biomass and extracellular enzyme activities control the rate of soil organic carbon decomposition,thereby affecting soil carbon pool.However,seasonal dynamics of soil microbial properties at different depths of the soil profile remain unclear.In this study,we sampled soils in the early,middle and late growing season at different soil depths(0–100 cm)in two alpine ecosystems(meadow and shrubland)on the Tibetan Plateau.We measured plant belowground biomass,soil properties,microbial biomass and extracellular enzyme activities.We found that soil properties changed significantly with sampling time and soil depth.Specifically,most of soil properties consistently decreased with increasing soil depth,but inconsistently varied with sampling time.Moreover,root biomass and microbial biomass decreased with increasing soil depth and increased with sampling time during the growing season.However,microbial extracellular enzyme activities and their vector properties all changed with depth,but did not vary significantly with time.Taken together,these results show that soil properties,microbial biomass and extracellular enzyme activities mostly decline with increasing depth of the soil profile,and soil properties and microbial biomass are generally more variable during the growing season than extracellular enzyme activities across the soil profile in these alpine ecosystems.Further studies are needed to investigate the changes in soil microbial community composition and function at different soil depths over the growing season,which can enhance our mechanistic understanding of whole-profile soil carbon dynamics of alpine ecosystems under climate change.展开更多
基金This work was supported by the Anhui Provincial Program on Key Research and Development Project(Grant No.202004a06020021)the National Natural Science Foundation of China(Grant No.21606002)+1 种基金the Natural Science Foundation of Anhui Province(CN)(Grant No.1708085QC64)the Undergraduate Research Training Programs for Innovation(Grant Nos.201910357069,S201910357427).
文摘Fungi play an important role in dying wastewater treatment.In this work,the mycelia of Lactarius deliciosus exhibited an excellent capacity in decolorizing coomassie brilliant blue(CBB).The results demonstrated that the mycelia could treat CBB with high concentrations over a broad range of pH and temperature.The decolorization rate of 99.19%and the removal rate of 16.31 mg·L^(‒1)·h were realized.The mycelia could be recycled from decolorizing process for 19 times,indicating a good re-usability.It verified that the lignin peroxidase(121.65 U·L^(‒1))and manganese peroxidase(36.77 U·L^(‒1))were involved in the degradation and decolorization process of CBB.Toxicity assessments indicated the seed germination rate was up to 82.22%while inhibition to Escherichia coli decreased dramatically and no significant effect on Caenorhabditis elegans growth was found.The removal of CBB was a synergistic process accomplished by adsorption and biodegradation.The mycelia could be used for eco-friendly CBB treatment.
基金supported by the National Natural Science Foundation of China (No.31670496)。
文摘Changbai Mountain,central in the distribution of Pinus koraiensis,supports a virgin Korean pine forest with vertical gradient distribution.Soil extracellular enzyme activity(EEA) and enzyme stoichiometry(ES) are reliable indicators of the energy and nutrients utilized by microbial communities and of soil nutrient changes.We measured four representative soil EEAs(sucrase,cellulase,urease,acid phosphatase) at two soil layers(A:0-5 cm and B:5-10 cm)beneath Korean pine forest at five elevations on Changbai Mountain during growing season.The vertical and seasonal variations of EEAs were analyzed by soil enzyme stoichiometry to quantify the role of soil microorganism in the nutrient cycling process.The activities of four soil extracellular enzymes and the ratios of enzyme activity to soil microbial biomass carbon(EA/SMBC) did not vary with elevation.The first partition point of multiple regression trees was in September,and the second branch was split by elevation.Seasonal change had more influence on soil enzyme activity(A layer:75.6%;B layer:71.3%) than did change in elevation(A layer:7.8%;B layer:7.5%).Over one entire growing season,both vector length and vector angle were unchanged by elevation,but varied significantly by month.Among the soil physicochemical factors,available phosphorus and pH were the main factors affecting the four soil EE As.The ratio of basal area of the coniferous tree to broad-leaved tree species(S_(con)/S_(br)),soil microbial biomass carbon(MBC) and nitrogen(MBN) influenced the four soil EE As.The results of vector analysis revealed that C and N sources were generally sufficient,but P was limiting(vector angle> 45°).The vector angle for September was significantly higher than for other months.This result verified that phosphorus was the limiting factor affecting soil microorganism function in nutrient metabolism and cycling.Soil enzyme stoichiometry proved to be an efficient index for quantifying soil microorganismmediated nutrient cycling in the Korean pine ecosystem.
基金financially supported by the Agro-scientific Research in the Public Interest of China (201503122)the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences (CAASXTCX2016008)the National Natural Science Foundation of China (41620104006)
文摘Although returning crop residue to fields is a recommended measure for improving soil carbon(C)stocks in agroecosystems,the response of newly formed soil C(NFC)to the integrated supply of residue and nutrients and the microbial mechanisms involved in NFC are not fully understood.Therefore,an 84-day incubation experiment was conducted to ascertain the microbial mechanisms that underpin the NFC response to inputs of residue and nitrogen(N),phosphorus(P),and sulfur(S)in two black(Phaeozem)soils from experimental plots at Gongzhuling,Jilin Province and Hailun,Heilongjiang Province,China.The results showed that adding residue alone accelerated microbial nutrient mining,which was supported by decreases of 8^(-1)6%in the ratios of C:N and C:P enzyme activities,relative to soils with nutrient inputs.The NFC amounts increased from 1156 to 1722 mg kg^(−1) in Gongzhuling soil and from 725 to 1067 mg kg^(−1) in Hailun soil as the levels of nutrient supplementation increased.Boosted regression tree analysis suggested thatβ-glucosidase(BG),acid phosphatase(AP),microbial biomass C(MBC),and Acidobacteria accounted for 27.8,18.5,14.7,and 8.1%,respectively,of the NFC in Gongzhuling soil and for 25.9,29.5,10.1,and 13.9%,respectively,of the NFC in Hailun soil.Path analysis determined that Acidobacteria positively influenced NFC both directly and indirectly by regulating BG,AP,and MBC,in which MBC acquisition was regulated more by AP.The amount of NFC was lower in Hailun soil than in Gongzhuling soil and was directly affected by AP,indicating the importance of soil properties such as SOC and pH in determining NFC.Overall,our results reveal the response of NFC to supplementation by N,P,and S,which depends on Acidobacteria and Proteobacteria,and their investment in BG and AP in residue-amended soil.
基金by National Natural Science Foundation of China,No.81673944.
文摘BACKGROUND Extracellular matrix(ECM)remodeling and stiffening,which are correlated with tumor malignancy,drives tumor development.However,the relationship between ECM remodeling and rat experimental model of 1,2-dimethylhyrazine(DMH)-induced colorectal cancer(CRC)imposed by cold and capsaicin exposure remains unclear.AIM To explore the effects of cold exposure and capsaicin on ECM remodeling and ECM enzymes in DMH-induced CRC.METHODS For histopathological analysis,the sections of colon tissues were stained with hematoxylin and eosin,Masson’s trichrome,Picrosirius red,and Weigert’s Resorcin-Fuchsin to observe the remodeling of collagen and elastin.Additionally,the protein expression level of type I collagen(COL I),type 3 collagen(COL III0,elastin,matrix metalloproteinase(MMP)1,MMP2,MMP9,and tissue-specific matrix metalloproteinase 1(TIMP1)was assessed by immunohistochemistry.The messenger RNA(mRNA)levels of COL I,COL III,elastin,and lysyl oxidase-like-2(LOXL2)in the colon tissues of rats was measured by reverse-transcriptase quantitative polymerase chain reaction.RESULTS Although no differences were observed in the proportion of adenomas,a trend towards the increase of invasive tumors was observed in the cold and capsaicin group.The cold exposure group had a metastasis rate compared with the other groups.Additionally,abnormal accumulation of both collagen and elastin was observed in the cold exposure and capsaicin group.Specifically,collagen quantitative analysis showed increased length,width,angle,and straightness compared with the DMH group.Collagen deposition and straightness were significantly increased in the cold exposure group compared with the capsaicin group.Cold exposure and capsaicin significantly increased the protein levels of COL I,elastin,and LOXL2 along with increases in their mRNA levels in the colon tissues compared with the DMH group,while COL III did not show a significant difference.Furthermore,in immunohistochemical evaluations,MMP1,MMP2,MMP9,and TIMP1 staining increased in the cold exposure and capsaicin group compared with the DMH group.CONCLUSION These results suggest that chronic cold and capsaicin exposure further increased the deposition of collagen and elastin in the colonic tissue.Increased COL I and elastin mRNA and protein levels expression may account for the enhanced ECM remodel and stiffness variations of colon tissue.The upregulated expression of the LOXL2 and physiological imbalance between MMP/TIMP activation and deactivation could contribute to the progression of the CRC resulting from cold and capsaicin exposure.
基金supported by the National Key Technolo-gy R&D Program(No.2006BAC06B04,2006BAC02A03)the Key Grant Project of Shanghai Committee of Science and Technology(No.06dz12308).
文摘The high water content of municipal solid waste(MSW)will reduce the effciency of mechanical sorting,consequently unfavorable for beneficial utilization.In this study,a combined hydrolytic-aerobic biodrying technology was introduced to remove water from MSW.The total water removals were proved to depend on the ventilation frequency and the temporal span in the hydrolytic stage. The ventilation frequency of 6 times/d was preferable in the hydrolytic stage.The hydrolytic span should not be prolonged more than 4 d.At this optimal scenario,the final water content was 50.5%reduced from the initial water content of 72.0%,presenting a high water removal effciency up to 78.5%.A positive correlation was observed between the organics losses and the water losses in both hydrolytic and aerobic stages(R=0.944,p<0.01).The evolutions of extracellular enzyme activities were shown to be consistent with the organics losses.
基金funding from EU H2020 Marie SkłodowskaCurie Actions(No.839806)Aarhus Universitets Forskningsfond(AUFF-E-2019-7-1)+3 种基金Danish Independent Research Foundation(1127-00015B)Nordic Committee of Agriculture and Food Researchsupported by Natural Environment Research Council(NERC)EAO Doctoral Training Partnership(NE/L002469/1)supported by a Ramon Areces Foundation research Fellowship and BBSRC Discovery Fellowship(BB/S010661/1).
文摘Mangroves are one of the most ecologically sensitive ecosystems to global climate change,which have cascading impacts on soil carbon(C),nitrogen(N)and phosphorus(P)cycling.Moreover,mangroves are experiencing increasing N and P loadings and reduced oxygen availability due to intensified climate change and human activities.However,both direct and interactive effects of these perturbations on microbially mediated soil C,N and P cycling are poorly understood.Here,we simultaneously investigated the effects of N and P loadings and reduced oxygen on microbial biomass,microbial respiration,and extracellular enzyme activities(EEAs)in mangrove soils.We calculated the microbial metabolic quotient(qCO_(2)),which is regarded as a useful inverse metric of microbial C use efficiency(CUE).Our results show that reduced oxygen significantly increases both qCO_(2) and microbial specific EEAs(enzyme activity per unit of microbial biomass)for C-,N-and P-acquisition regardless of N or P loadings.Furthermore,we found that qCO_(2) positively correlated with microbial specific EEAs under reduced oxygen,whereas no clear relationship was detected under ambient oxygen.These results suggest that reduced oxygen increases microbial specific EEAs at the expense of increasing microbial respiration per unit biomass,indicating higher energy cost per unit enzyme production.
基金Financial support by the German Research Foundation (DFG) (SCHW750/9) in the frame of the Priority Program SPP 1315。
文摘The proportion of organic matter and mineral composition are important factors determining the formation and type of non-extractable residues(NERs) of pesticides in soil. In this study, we investigated the enantioselectivity in degradation and NER formation of the chiral fungicide metalaxyl in soil particle size fractions(silt and clay). Microbial and extracellular enzyme activities during these processes were monitored in incubation of silt and clay samples isolated from sterilized and non-sterilized soil samples collected from a long-term agricultural field experimental site in Ultuna, Sweden. The temporal influence on the fate of the fungicide was noted by short-term(10-d) and long-term(92-d) incubations. Besides the acquisition of quantitative data with gas chromatography-mass spectrometry(GC/MS), stereoselective analyses were performed with chiral GC/MS. Quantitative results pointed to a higher metabolism rate of the pesticide through microbial activity than through extracellular enzyme activity. This was also confirmed by the enantioselective depletion of R-metalaxyl and the subsequent formation of R-metalaxyl acid in microbially active samples from non-sterilized soil. The silt fraction containing a high amount of organic matter exhibited a significant hydrolyzable proportion of metalaxyl NERs that was releasable under alkaline conditions. On the contrary, the clay fraction showed an enhanced affinity for covalently bound residues. Based on our results, we recommend differentiating between reversibly and irreversibly bound proportions of pesticides in persistence and environmental risk assessment because the reversible fraction contained potentially bioavailable amounts of residues that may be released under natural conditions.
文摘Wallemia comprises air-and food-borne,mycotoxigenic contaminants including the halophilic W.ichthyophaga,xerotolerant W.sebi and xerophilic W.muriae.Wallemia isolates are easily overlooked and only a comparably small number of strains have been deposited in culture collections so far.In order to better understand the natural distribution of Wallemia spp.and to encounter their natural habitats,we tested more than 300 low-water-activity substrates and 30 air samples from a wide geographical coverage.We isolated more than 150 new Wallemia strains.Wallemia sebi and W.muriae were isolated mostly from hypersaline water,low-water-activity foods,plant materials and indoor.Wallemia muriae is the dominant Wallemia species in the air of natural and human influenced environments in Europe.New isolates of W.ichthyophaga were obtained from hypersaline environments such as brine,salt crystals,salty foods and MgCl_(2)-rich bitterns,and from the air of hay barns in Denmark.Five halotolerant strains were recognised as a hitherto un-described species Wallemia hederae,the phylogenetic sister of the halophilic W.ichthyophaga.Wallemia spp.show in-vitro growth on media that contain the chaotropic salt MgCl_(2).Wallemia ichthyophaga can grow in liquid medium enriched with 2 M MgCl_(2).Never before has a microorganism been grown on comparably high MgCl_(2) concentrations.Tests of the activity of a wide range of extracellular enzymes in the presence of NaCl also suggested that Wallemia iswell-adapted to substrates with a reduced water activity.
基金This study was supported by projects of the National Natural Science Foundation of China(Nos.31972939,31630009 and 31670325)the National Basic Research Pro-gram of China(No.2016YFC0500701)+1 种基金the Research Fund of the State Key Laboratory of Soil and Sustainable Agri-culture,Nanjing Institute of Soil Science,Chinese Academy of Sciences(No.Y412201439)the University Con-struction Projects from the Central Authorities in Beiing of China.
文摘Soil microorganisms play a key role in soil organic matter dynamics, nutrient cycling, and soil fertility maintenance in forest ecosystems, and they are influenced by stand age and soil depth. However, few studies have simultaneously considered these two factors. In this study, we measured soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil basal respiration (SBR) rate, and potential extracellular enzyme activity (EEA) in soil to a depth of 60 cm under 10-, 30-, and 40-year-old Scots pine (Pinus sylvestris var. mongolica) stands (Y10, Y30, and Y40, respectively) in plantations in northern China in 2011. Soil water content (SWC), soil pH, soil organic carbon (SOC), and soil total nitrogen (STN) were also measured to explore their effects on soil microbial indices across different stand ages and soil depths. Our results showed that SMBC, SMBN, and the SBR rate were generally higher for the Y30 stand than for the Y10 and Y40 stands. Potential EEA, except forα-glucosidase, decreased significantly with increasing stand age. Soil organic carbon,STN, SWC, and soil pH explained 67%of the variation in soil microbial attributes among the three stand ages. For the same stand age, soil microbial biomass and the SBR rate decreased with soil depth. Lower microbial biomass, lower SBR rate, and lower EEA for the mature Y40 stand indicate lower substrate availability for soil microorganisms, lower soil quality, and lower microbial adaptability to the environment. Our results suggest that changes in soil quality with stand age should be considered when determining the optimum rotation length of plantations and the best management practices for afforestation programs.
基金United States Department of Agriculture National Institute of Food and Agriculture Hatch program(NYC-145403)the New York State Turfgrass Association and the US Department of Energy,Office of Science,Office of Biological and Environmental Research Terrestrial Ecosystem Science Program(DE-AC02-05CH11231).
文摘Aims Plants generally respond to nitrogen(N)fertilization with increased growth,but N addition can also suppress rhizosphere effects,which consequently alters soil processes.We quantified the influence of N addition on rhizosphere effects of two C4 grasses:smooth crabgrass(Digitaria ischaemum)and bermudagrass(Cynodon dactylon).Methods Plants were grown in nutrient-poor soil for 80 days with either 20 or 120μg NH4No3-N g dry soil−1.N mineralization rates,microbial biomass,extracellular enzyme activities and bacterial community structure were measured on both rhizosphere and bulk(unplanted)soils after plant harvest.Important Findings Fertilization showed nominal differences in net N mineralization,extracellular enzyme activity and microbial biomass between the rhizosphere and bulk soils,indicating minimal influence of N on rhizosphere effects.Instead,the presence of plant roots showed the strongest impact(up to 80%)on rates of net N mineralization and activities of three soil enzymes indicative of N release from organic matter.Principal component analysis of terminal restriction fragment length polymorphism(t-rFlP)also reflected these trends by highlighting the importance of plant roots in structuring the soil bacterial community,followed by plant species and N fertilization(to a minor extent).overall,the results indicate minor contributions of short-term N fertilization to changes in the magnitude of rhizos-phere effects for both grass species.
基金the National Natural Science Foundation of China(31971528 and 31988102).
文摘Microbial biomass and extracellular enzyme activities control the rate of soil organic carbon decomposition,thereby affecting soil carbon pool.However,seasonal dynamics of soil microbial properties at different depths of the soil profile remain unclear.In this study,we sampled soils in the early,middle and late growing season at different soil depths(0–100 cm)in two alpine ecosystems(meadow and shrubland)on the Tibetan Plateau.We measured plant belowground biomass,soil properties,microbial biomass and extracellular enzyme activities.We found that soil properties changed significantly with sampling time and soil depth.Specifically,most of soil properties consistently decreased with increasing soil depth,but inconsistently varied with sampling time.Moreover,root biomass and microbial biomass decreased with increasing soil depth and increased with sampling time during the growing season.However,microbial extracellular enzyme activities and their vector properties all changed with depth,but did not vary significantly with time.Taken together,these results show that soil properties,microbial biomass and extracellular enzyme activities mostly decline with increasing depth of the soil profile,and soil properties and microbial biomass are generally more variable during the growing season than extracellular enzyme activities across the soil profile in these alpine ecosystems.Further studies are needed to investigate the changes in soil microbial community composition and function at different soil depths over the growing season,which can enhance our mechanistic understanding of whole-profile soil carbon dynamics of alpine ecosystems under climate change.
