Root phosphatase activity is a competitive trait affiliated with the conservation gradient in root economic space

Background:The diversity of resource acquisition strategies of plant roots determines the species coexistence patterns to a certain extent.However,few root physiological traits have been investigated,such as root phosphatase activity(PA)that affects plant phosphorus(P)uptake.Methods:Root PA and classical root functional traits were investigated for 21 coexisting species in a deciduous broad-leaved forest in warm temperate-subtropical transition zone,China.We analyzed the root order variation of absorptive fine root PA,clarified the attribution of root PA in root economic space(RES)and the different P acquisition strategies of co-occurring species based on the multidimensional RES theory,and determined the dominant factors affecting interspecific variation in root PA.Results:There was no distinct pattern of PA variation with root order in the first three root orders of absorptive fine roots,and root PA was constrained by phylogeny.Root PA is a competitive trait affiliated with the conservation gradient in RES.The tight linkages among root PA,mycorrhizal colonization,diameter,specific root length,and nitrogen concentration suggested trade-offs among P acquisition strategies of co-occurring species,i.e.species with long and fine roots acquire inorganic P by actively exploring the soil and secreting phosphatase to mineralize and hydrolyze organic P,while species with short and thick roots obtain P mainly by investing C in mycorrhizal partners.Conclusions:Collectively,our study provides an insight into the forest species coexistence in climatic transition zones,i.e.species coexistence mechanisms based on diverse phosphorus acquisition strategies.

Effect of dissolved phosphorus on alkaline phosphatase activity in marine microalgae

Alkaline phosphatase activity (APA) and dissolved phosphorus were monitored during the batch cultures of two bone microalgae. Results indicate that variation of APA was in the shape of 'S' curve. Different specs of dissolved phaphorus had different effects on APA. The concentrations of dis solved inorganic phosphorus (DIP) and and molecular dissolved organic phosphorus (SDOP) had a sig nificant effect on APA, while the concentration of large molecular dissolved organic phosphorus (LDOP) had a little effect on APA., and the increase of APA could accelerate the decomposing of LDOP in the medium. Results also show that algae species and abundance had why a little effect on APA.

Detection of Ca^(2+)-dependent acid phosphatase activity identifies neuronal integrity in damaged rat central nervous system after application of bacterial melanin

The study aims to confirm the neuroregenerative effects of bacterial melanin （BM） on central nervous system injury using a special staining method based on the detection of Ca^2＋-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex （group I; n = 12） or unilateral rubrospinal tract transection at the cervical level （C3-4） （group II; n = 12）. In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution （BM subgroup） and the remaining six rats were intramuscularly in）ected with saline （saline subgroup）. Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca^2＋-dependent acid phosphatase activity detection in combination with Chilingarian＇s calcium adenoside triphosphate method revealed that BM stimulated the sprouting of fibers and dilated the capillaries in the brain and spinal cord. These results suggest that BM can promote the recovery of motor function of rats with central nervous system injury; and detection of Ca^2＋-dependent acid phosphatase activity is a fast and easy method used to study the regeneration-promoting effects of BM on the injured central nervous system.

Synthesis of dihalogenated coumarin derivatives for monitoring acid phosphatase activity

Aim To synthetize 6-chloro-8-fluoro-4-methylumbelliferone phosphate(CF-MUP) and utilize it to analyze acid phosphatase activity.Method CF-MUP obtained by phosphorylation of CFMU(6-chloro-8-fluoro-4-methylumbelliferone) which was prepared by Pechmann reaction between 4 and ethyl acetoacetate in the presence of methanesulfonic acid.And then,the utility of CF-MUP as a substrate for acid phosphatase was compared with MUP(4-methylumbelliferone phosphate).Results The new coumarin phosphate,CF-MUP,demonstrated much higher sensitivity and was more robust for detecting the activity of acid phosphatase than MUP in the physiological pH range.Conclusion This new fluorescence dye,CF-MUP,is a convenient tool for the continuous assay of acid phosphatases with a wide range of pH.

Influence of sodium fluoride on alkaline phosphatase activity and bone gla protein synthesis in human yellow ligament cells in vitro

Objective To investigate the influence of sodium fluoride(NaF)on alkaline phosphatase(ALP)activity and bone gla protein(BGP)synthesis in yellow ligament cells from different surgical simples in vitro.Methods The human ligament cells

Responses of alkaline phosphatase activity to wind-driven waves in a large,shallow lake:Implications for phosphorus availability and algal blooms

Phosphorus is a vital nutrient for algal growth,thus,a better understanding of phosphorus availability is essential to mitigate harmful algal blooms in lakes.Wind waves are a ubiquitous characteristic of lake ecosystems.However,its effects on the cycling of organic phosphorus and its usage by phytoplankton remain poorly elucidated in shallow eutrophic lakes.A mesocosm experiment was carried out to investigate the responses of alkaline phosphatase activity fractions to wind waves in large,shallow,eutrophic Lake Taihu.Results showed that wind-driven waves induced the release of alkaline phosphatase and phosphorus from the sediment,and dramatically enhanced phytoplanktonic alkaline phosphatase activity.However,compared to the calm conditions,bacterial and dissolved alkaline phosphatase activity decreased in wind-wave conditions.Consistently,the gene copies of Microcystis phoX increased but bacterial phoX decreased under wind-wave conditions.The ecological effects of these waves on phosphorus and phytoplankton likely accelerated the biogeochemical cycling of phosphorus and promoted phytoplankton production in Lake Taihu.This study provides an improved current understanding of phosphorus availability and the phosphorus strategies of plankton in shallow,eutrophic lakes.

Phosphorus Starvation-induced Expression of Leaf Acid Phosphatase Isoforms in Soybean

Leaf acid phosphatase (APase) activities of 274 soybean genotypes were surveyed under field conditions with two levels of P supplies, and a nutrient solution culture experiment with eight selected genotypes was subsequently conducted under greenhouse conditions to further characterize APase activity and its isoform expression induced by P starvation. Results from the field experiment showed that there was a great genotypic variation for leaf APase activity among the tested soybean genotypes from different origins, and APase activity in many of the tested genotypes (about 60%) was generally increased in the treatment without P fertilizer addition. Results from the nutrient solution culture experiment showed that APase activity in all the eight tested genotypes was generally enhanced by P starvation. Six isoforms of APases were detected in isoelectric focusing gels with samples from both young and old leaves. The activity of all the six isoforms was increased by P starvation, but no new APase isoform was induced. Our results suggest that leaf APase activity could serve as an enzymatic indicator of P starvation for soybean; the increase in leaf APase activity under low P stress was mainly caused by the increase in the activity of existing isoforms but not by the induction of new isoforms.

Effects of a decade of organic fertilizer substitution on vegetable yield and soil phosphorus pools, phosphatase activities, and the microbial community in a greenhouse vegetable production system

Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated the effects of longterm organic substitution on soil P availability and microbial activity in greenhouse vegetable fields.A 10-year(2009–2019)field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools,phosphatase activities and the microbial community,and identify factors that regulate these soil P transformation characteristics.Four treatments included 100%chemical N fertilizer(4 CN),50%substitution of chemical N by manure(2 CN+2 MN),straw(2 CN+2 SN),and combined manure with straw(2 CN+1 MN+1 SN).Compared with the 4 CN treatment,organic substitution treatments increased celery and tomato yields by 6.9-13.8%and 8.6-18.1%,respectively,with the highest yields being in the 2 CN+1 MN+1 SN treatment.After 10 years of fertilization,organic substitution treatments reduced total P and inorganic P accumulation,increased the concentrations of available P,organic P,and microbial biomass P,and promoted phosphatase activities(alkaline and acid phosphomonoesterase,phosphodiesterase,and phytase)and microbial growth in comparison with the 4 CN treatment.Further,organic substitution treatments significantly increased soil C/P,and the partial least squares path model(PLS-PM)revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield.Partial least squares(PLS)regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities.Our results suggest that organic fertilizer substitution can promote soil P transformation and availability.Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices.

Soil Phosphorus Composition and Phosphatase Activities along Altitudes of Alpine Tundra in Changbai Mountains,China

Alpine tundra ecosystems have specific vegetation and environmental conditions that may affect soil phosphorus （P） composition and phosphatase activities. However, these effects are poody understood. This study used NaOH-EDTA extraction and solution ^31P nuclear magnetic resonance （NMR） spectroscopy to determine soil P composition and phosphatase activities, including acid phosphomonoesterase （AcP）, phosphodiesterase （PD） and inorganic pyrophosphatase （IPP）, in the alpine tundra of the Changbai Mountains at seven different altitudinal gradients （i.e., 2000 m, 2100 m, 2200 m, 2300 m, 2400 m, 2500 m, and 2600 m）. The results show that total P （TP）, organic P （OP）, OP/TP, NaOH-EDTA extracted P and AcP, PD, and IPP activities over the altitude range of 2500-2600 m are significantly lower than those below 2400 m. The dominant extracted form of P is OP （73%0-83%） with a large proportion of monoesters （65%0-72%）, whereas inorganic P is present in lower proportions （17%-27%）. The activity of AcP is significantly positively correlated with the contents of soil OP, total carbon （TC）, total nitrogen （TN）, and TP （P 〈 0.05）, indicating that the AcP is a more sensitive index for responding P nutrient storage than PD and IPP. Soil properties, P composition, and phosphatase activities decrease with increased altitude and soil pH. Our results indicate that the distribution of soil P composition and phosphatase activities along altitude and AcP may play an important role in P hydrolysis as well as have the potential to be an indicator of soil quality.

Cantharidin and Its Analogues:Anticancer and Ser/Thr Protein Phosphatase Inhibitory Activities

This paper mainly describes the anticancer activities and Ser/Thr protein phosphatase inhibitory activities of cantharidin and its analogues.

Liming reduces soil phosphorus availability but promotes yield and P uptake in a double rice cropping system

Liming is often applied to alleviate soil acidification and increase crop yield on acidic soils,but its effect on soil phosphorus(P)availability is unclear,particularly in rice paddies.The objective of this study was to examine the effect of liming on rice production,yield and P uptake in a three-year field experiment in a double rice cropping system in subtropical China.We also conducted an incubation experiment to investigate the direct effect of liming on soil available P and phosphatase activities on paddy soils in the absence of plants.In the incubation experiment,liming reduced soil P availability(measured as Olsenextractable P)by 14–17%and inhibited the activity of soil acid phosphatase.Nonetheless,lime application increased grain yield,biomass,and P uptake in the field.Liming increased grain yield and P uptake more strongly for late rice(26 and 21%,respectively)than for early rice(15 and 8%,respectively).Liming reduced the concentration of soil available P in the field as well,reflecting the increase in rice P uptake and the direct negative effect of liming on soil P availability.Taken together,these results suggest that by stimulating rice growth,liming can overcome direct negative effects on soil P availability and increase plant P uptake in this acidic paddy soil where P is not the limiting factor.

ALP Induction by β－glycerophosphate during the Nonmineralization Phase In Vitro

β-GP influences on rat osteoblast development at the early period of culture i.e , the non-mineralization phase, and changes with the different cell passages were investigated. Alkaline phosphatase (ALP) was chosen as a main object. Northern blot analysis revealed up to two-fold increase in the steady statelevel of ALP mRNA after stimulation of rat osteoblast with 10 mM β-GP- Likewise, 10 mM β-GP induced a 10─30 % increase in ALP activity (P< 0. 01) of early passages (1 to 4), but not of later passages (5 to 6). The β-GP induced increase in ALP activity was totally inhibited by the protein synthesis inhibitor, cycloheximide (50 μM).β- GP stimulation was found to be without effect on cell proliferation measured as 3H-thymidine incorporation. It is concluded that β-GP has no effect on proliferation but induces an increase in both mRNA level and activity of ALP in the non-mineralization phase of cultures of fetal rat calvarial cells , which lasts for several passages but will disappear in older cultures.

Three New Humulane Sesquiterpenes from Cultures of the Fungus Antrodiella albocinnamomea

Three new humulane-type sesquiterpenes,antrodols A–C(1–3),were isolated from cultures of the fungus Antrodiella albocinnamomea.Their structures were elucidated on the basis of extensive spectroscopic analysis.Antrodols A–C(1–3)are first examples of humulane-type sesquiterpenes isolated from cultures of higher fungi,and antrodol A(1)was the first report of humulane-type sesquiterpene with a methyl rearranged at C-3.All compounds were evaluated in the enzyme inhibition assay against two protein-tyrosine phosphatases(PTPs):MEG2 and PTP1Bc.

Comparative genetic analysis of Arabidopsis purple acid phosphatases AtPAP10, AtPAP12, and AtPAP26 provides new insights into their roles in plant adaptation to phosphate deprivation

Induction and secretion of acid phosphatases （APases） is thought to be an adaptive mechanism that helps plants survive and grow under phosphate （Pi） deprivation, in Arabidopsis, there are 29 purple acid phosphatase （AtPAP） genes. To systematically investigate the roles of different AtPAPs, we first identified knockout or knock-down T-DNA lines for all 29 AtPAP genes. Using these atpap mutants combined with in-gel and quantitative APase enzyme assays, we demonstrated that AtPAP12 and AtPAP26 are two major intracellular and secreted APases in Arabidopsis while AtPAPlo is mainly a secreted APase. On Pi-deficient （P-） medium or P- medium supplemented with the organophosphates ADP and fructose-6-phosphate （Fru-6-P）, growth of atpaplo was significantly reduced whereas growth of atpap12 was only moderately reduced, and growth of atpap26 was nearly equal to that of the wild type （WT）. Overexpression of the AtPAP12 or AtPAP26 gene, however, caused plants to grow better on P- or P- medium supplemented with ADP or Fru-6-P. Interest-ingly, Pi levels are essentially the same for the WT and overexpressing lines, although these two types of plants have significantly different growth phenotypes. These results suggest that the APases may have other roles besides enhancing internal Pi recycling or releasing Pi from external organophosphates for plant uptake.

Effect of microcystin-LR on protein phosphatase 2A and its function in human amniotic epithelial cells

Due to their toxicity,the increased distribution of microcystins(MCs) has become an important worldwide problem.MCs have been recognized as inhibitors of protein phosphatase 2A(PP2A) through their binding to the PP2A catalytic subunit.However,the exact mechanism of MC toxicity has not been elucidated,especially concerning the cellular response and its autoregulation.To further dissect the role of PP2A in MC-induced toxicity,the present study was undertaken to determine the response of PP2A in human amniotic epithelial(FL) cells treated with microcystin-LR(MCLR),one of the MC congeners.The results show that a low-dose treatment of MCLR in FL cells for 6 h induced an increase in PP2A activity,and a high-dose treatment of MCLR for 24 h decreased the activity of PP2A,as expected.The increased mRNA and protein levels of the PP2A C subunit may explain the increased activity of PP2A.Furthermore,MCLR altered microtubule post-translational modifications through PP2A.These results further clarify the underlying mechanism how MCLR affects PP2A and may be helpful for elucidating the complex toxicity of MCLR.

Osteogenic lithium-doped brushite cements for bone regeneration

This study investigated the osteogenic performance of new brushite cements obtained from Li+-dopedβ-tricalcium phosphate as a promising strategy for bone regeneration.Lithium(Li+)is a promising trace element to encourage the migration and proliferation of adipose-derived stem cells(hASCs)and the osteogenic differentiation-related gene expression,essential for osteogenesis.In-situ X-ray diffraction(XRD)and in-situ 1H nuclear magnetic resonance(1H NMR)measurements proved the precipitation of brushite,as main phase,and monetite,indicating that Li+favored the formation of monetite under certain conditions.Li+was detected in the remaining pore solution in significant amounts after the completion of hydration.Isothermal calorimetry results showed an accelerating effect of Li+,especially for low concentration of the setting retarder(phytic acid).A decrease of initial and final setting times with increasing amount of Li+was detected and setting times could be well adjusted by varying the setting retarder concentration.The cements presented compressive mechanical strength within the ranges reported for cancellous bone.In vitro assays using hASCs showed normal metabolic and proliferative levels.The immunodetection and gene expression profile of osteogenic-related markers highlight the incorporation of Li+for increasing the in vivo bone density.The osteogenic potential of Li-doped brushite cements may be recommended for further research on bone defect repair strategies.

Effect of Conservation Tillage Practices on Soil Phosphorus Nutrition in an Apple Orchard

Soil phosphorus(P) is an essential and limiting element for plant growth, which is significantly affected by different approaches to soil management. In order to reveal the effect of different management approaches on soil P and phosphatase activity in 0–20 cm and 20–40 cm soil, this research was conducted to study variations in the characteristics of P and phosphatase activity under 3-year tillage without mulching(CK), notillage with corn straw mulching(NTSM) and no-tillage with grass(NTG) in Liaoning apple orchard. The results showed that NTSM and NTG could significantly increase soil P content(P < 0.05) as compared with CK. However, the effect was different between NTSM and NTG; with the NTSM approach, the improvement in the P content in 20–40 cm was remarkable, and in the NTG approach, the improvement in the soil surface P content was significant. At the same time, soil phosphatase activity significantly increased(P < 0.05) under NTSM and NTG. The soil surface and 20–40 cm phosphodiesterase(PD) activity was enhanced under the two management approaches, however, the effect of NTG was stronger than NTSM. In addition, NTSM was more conducive to increasing alkaline phosphomonoesterase(Al P), and NTG was more conducive to increasing acid phosphomonoesterase(Ac P). Our findings highlight the variation of dominant mechanisms involved in soil P with different mulching materials application. NTSM and NTG could have the potential to increase P content and phosphatase activity, and provide a basis for using this method to improve P phytoavailability and reduce the application of soil fertilizer.

Influence of phosphorus availability on the community structure and physiology of cultured biofilms

Biofilms have important effects on nutrient cycling in aquatic ecosystems.However,publications about the community structure and functions under laboratory conditions are rare.This study focused on the developmental and physiological properties of cultured biofilms under various phosphorus concentrations performed in a closely controlled continuous flow incubator.The results showed that the biomass（Chl a）and photosynthesis of algae were inhibited under P-limitation conditions,while the phosphatase activity and P assimilation rate were promoted.The algal community structure of biofilms was more likely related to the colonization stage than with the phosphorus availability.Cyanobacteria were more competitive than other algae in biofilms,particularly when cultured under low P levels.A dominance shift occurred from non-filamentous algae in the early stage to filamentous algae in the mid and late stages under P concentrations of 0.01,0.1 and 0.6 mg/L.However,the total N content,dry weight biomass and bacterial community structure of biofilms were unaffected by phosphorus availability.This may be attributed to the low respiration rate,high accumulation of extracellular polymeric substances and high alkaline phosphatase activity in biofilms when phosphorus availability was low.The bacterial community structure differed over time,while there was little difference between the four treatments,which indicated that it was mainly affected by the colonization stage of the biofilms rather than the phosphorus availability.Altogether,these results suggested that the development of biofilms was influenced by the phosphorus availability and/or the colonization stage and hence determined the role that biofilms play in the overlying water.