Soybean(Glycine max)rhizosphere organic phosphorus recycling relies on acid phosphatase activity and specific phosphorusmineralizing-related bacteria in phosphate deficient acidic soils

Bacteria play critical roles in regulating soil phosphorus(P) cycling. The effects of interactions between crops and soil P-availability on bacterial communities and the feedback regulation of soil P cycling by the bacterial community modifications are poorly understood. Here, six soybean(Glycine max) genotypes with differences in P efficiency were cultivated in acidic soils with long-term sufficient or deficient P-fertilizer treatments. The acid phosphatase(AcP) activities, organic-P concentrations and associated bacterial community compositions were determined in bulk and rhizosphere soils. The results showed that both soybean plant P content and the soil AcP activity were negatively correlated with soil organic-P concentration in P-deficient acidic soils. Soil P-availability affected the ɑ-diversity of bacteria in both bulk and rhizosphere soils. However, soybean had a stronger effect on the bacterial community composition, as reflected by the similar biomarker bacteria in the rhizosphere soils in both P-treatments. The relative abundance of biomarker bacteria Proteobacteria was strongly correlated with soil organic-P concentration and AcP activity in low-P treatments. Further high-throughput sequencing of the phoC gene revealed an obvious shift in Proteobacteria groups between bulk soils and rhizosphere soils, which was emphasized by the higher relative abundances of Cupriavidus and Klebsiella, and lower relative abundance of Xanthomonas in rhizosphere soils. Among them, Cupriavidus was the dominant phoC bacterial genus, and it was negatively correlated with the soil organic-P concentration. These findings suggest that soybean growth relies on organic-P mineralization in P-deficient acidic soils, which might be partially achieved by recruiting specific phoCharboring bacteria, such as Cupriavidus.

Soluble protein and acid phosphatase exuded by ectomycorrhizal fungi and seedlings in response to excessive Cu and Cd

Fungi and their symbionts can alleviate heavy metal stress by exuding soluble proteins and enzymes. This study examined the role of soluble protein and acid phosphatase （APase） exuded by Xerocomus chrysenteron, an ectomycorrhizal fungus, and the seedlings of its symbiont, Chinese pine （Pinus tabulaeformis）, under conditions of excessive Cu and Cd. The growth type showed that this poorly studied ectomycorrhizal fungus was capable of tolerating high concentrations of Cu, and may be useful in phytoremediation. X. chrysenteron grew well at 80 mg/L Cu, and the EC50 for Cd was 17.82 mg/L. X. chrysenteron also showed enhanced exudation of soluble protein in both isolated and inoculated cultivations under the influence of Cu and Cd. Soluble protein exudation, however, differed under Cu and Cd stress in isolates. In mediums containing Cu, soluble protein exudation increased with concentration, but in mediums containing Cd the content of soluble protein increased to a comparable level at all concentrations. This study demonstrated that soluble protein was related to heavy metal tolerance, although the different ions played different roles. While APase activity in exudates of fungi and seedlings decreased under Cu and Cd stress in comparison to the control, the APase activity in seedlings was maintained by inoculation. Thus, X. chrysenteron facilitated the ability of plant to maintain a normal nutrient uptake, and therefore to protect it from heavy metal toxicity.

Effect of acid phosphatase produced by Trichoderma asperellum Q1 on growth of Arabidopsis under salt stress

Salt stress is a major environmental factor that inhibits crop growth.Trichoderma spp.are the most efficient biocontrol fungi and some of the strains can stimulate plant growth.Phosphate solubilization is known as one of the main mechanisms in promoting plant growth,but the underlying mechanisms of phosphate solubilization in the salinity still need to be explored.The Trichoderma asperellum Q1 isolated and identified in our lab is a beneficial rhizosphere biocontrol fungus with a high phosphate solubilization activity.It could produce acid and alkaline phosphatases when using insoluble organic phosphorus as the sole phosphorus source,the salt stress increased the phosphorus-solubilization ability of the strain and the activities of the two enzymes.Furthermore,an acid phosphatase was purified from the fermentation broth by ammonium sulphate precipitation,ion-exchange,and gel filtration chromatography.Its molecular weight was 55 k Da as determined by SDS-PAGE.The purified acid phosphatase was used to investigate growth performance of Arabidopsis thaliana by plate assay and the result showed that it contributed to Arabidopsis growth by transforming organic phosphate into a soluble inorganic form under salt stress.To our knowledge,this is the first report on acid phosphatase purification from T.asperellum and its function in regulation of plant growth under salt stress.

Molecular Characterization and Functional Analysis of a New Acid Phosphatase Gene(Ha-acp1) from Heterodera avenae

For sedentary endo-parasitic nematodes, parasitism genes encoding secretory protein expressed in the subventral glands cells always play an important role during the early parasitic process. A new acid phosphatase gene （Ha-acp1） expressed in the subventral glands of the cereal cyst nematode （Heterodera avenae） was cloned and the characteristics of the gene were analyzed. Results showed that the gene had a putative signal peptide for secretion and in situ hybridization showed that the transcripts of Ha-acp1 accumulated speciifcally in the subventral gland cells of H. avenae. Southern blot analysis suggested that Ha-acp1 belonged to a multigene family. RT-PCR analysis indicated that this transcription was strong at the pre-parasitic juveniles. Knocking down Ha-acp1 using RNA interference technology could reduce nematode infectivity by 50%, and suppress the development of cyst. Results indicated that Ha-acp1 could play an important role in destroying the defense system of host plants.

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.

Mammalian-like Purple Acid Phosphatases in Plants

Introduction Purple acid phosphatases （PAPs） comprise of a family of binuclear metal-containing hydrolases, some members of which have been isolated and characterized from animal, plant and fungal sources . PAPs not only catalyze the hydrolyses of a wide range of phosphate esters and anhydrides under acidic reaction conditions, but also catalyze the generation of hydroxyl radicals in a Fenton-like reaction, by virtue of the presence of a redox-active binuclear metal center. Inmammals,

Effect of Salinity on Germination,Seedling Growth and Acid Phosphatase Activity in Lettuce

The impact of salt stress (NaCl 100 mM) on two lettuce varieties Romaine and Vista was conducted at germination and early seedling stages. The seeds of lettuce varieties were provided by the Seed Laboratory of Tunisian Ministry of Agriculture. The seeds were germinated in Petri dishes with double filter paper in distilled water (control) or NaCl solution (100 mM) for 5 days. The result showed that salinity significantly affected percentage and rate of germination in Vista variety but 100% of germination was found in Romaine. Length and fresh weight of root and shoot were reduced significantly with salt treatment in two lettuce varieties. Regarding biochemical analysis, acid phosphatase activity in root increased in Romaine and decreased in Vista. In shoot, this activity showed no difference with the control in the two varieties. However in cotyledons, and during 24 hours after germination, salinity decreased acid phosphatase activity in both varieties whereas in the later hours (48 - 96 h) this activity reached the value of the control in Romaine and Vista.

Effects of Lanthanum and Cerium on Acid Phosphatase Activities in Two Soils

To evaluate the security of using thulium, comparision between effects of La and those of Ce on acidic phosphatase activities in red soil and yellow soil in Zhejiang district was studied under conditions of ambient temperature and humidity. Results show that the acid phosphatase from different soil respondes to La and Ce differently. The activity of acid phosphatase in soil 1 declines with the increase of the concentration of La and Ce. The maximum inhibitory ratio of La and Ce reaches 69.8% and 71.0% respectively. But La and Ce have stimulative effect on the activity of acid phosphatase in soil 2. Under the effect of same concentration of the thulium, the acid phosphatase in two soils increases with the extending of culture time.

Overexpression of OsPAP10a, A Root-Associated Acid Phosphatase, Increased Extracellular Organic Phosphorus Utilization in Rice

Phosphorus （P） deficiency is a major limitation for plant growth and development. Among the wide set of responses to cope with low soil P, plants increase their level of intracellular and secreted acid phosphatases （APases）, which helps to catalyze inorganic phosphate （Pi） hydrolysis from organophosphates, in this study we characterized the rice （Oryza sativa） purple acid phosphatase 10a （OsPAPIOa）. OsPAPIOa belongs to group la of purple acid phosphatases （PAPs）, and clusters with the principal secreted PAPs in a variety of plant species including Arabidopsis. The transcript abundance of OsPAPIOa is specifically induced by Pi deficiency and is controlled by OsPHR2, the central transcription factor controlling Pi homeostasis. In gel activity assays of root and shoot protein extracts, it was revealed that OsPAPIOa is a major acid phosphatase isoform induced by Pi starvation. Constitutive overexpression of OsPAPIOa results in a significant increase of phosphatase activity in both shoot and root protein extracts. In vivo root 5-bromo.4-chloro-3-indolyl-phosphate （BCIP） assays and activity measurements on external media showed that OsPAPIOa is a root-associated APase. Furthermore, overexpression of OsPAPIOa significantly improved ATP hydrolysis and utilization compared with wild type plants. These results indicate that OsPAPIOa can potentially be used for crop breeding to improve the efficiency of P use.

Tartrate-resistant acid phosphatase 5b is a potential biomarker for rheumatoid arthritis： a pilot study in Han Chinese

Background Bone damage around the joints is one of the major pathophysiological mechanisms that leads to rheumatoid arthritis （RA） chronic disability.Serum tartrate-resistant acid phosphatase 5b （TRACP-5b） is secreted by osteoclasts,its activity can be used as a clinically relevant bone resorption marker.The aim of this study was to test whether the measurement of serum levels of TRACP-5b in patients with RA would correlate with measures of disease activity and with responses to therapy.Methods Fifty-six patients were randomly assigned to receive recombinant human cytotoxic tlymphocyte-associated antigen-4 immunoglobulin （RhCTLA4-lg）,infliximab or methotrexate （MTX）.The clinical and serologic indicators of RA activity were evaluated at baseline and at 24 weeks.Serum TRACP-5b was measured by Enzyme-linked Immunosorbent Assay （ELISA） at 0,12 and 24 weeks.Hand X-rays were obtained at baseline.Results At baseline,the levels of TRACP-5b correlated with the severity of X-ray damage,disease duration （r=0.332,P=0.012）,and tender joint count （r=0.408,P=0.002）.The 24 weeks values of TRACP-5b for RhCTLA4-lg group and infliximab group differed significantly from the baseline values in each group （P 〈0.05; P 〈0.05）,whereas only the value for RhCTLA4-lg group differed significantly from the 24 weeks value for the MTX group （P 〈0.01）.Considering the two biologics-treated groups together,the TRACP-5b levels at 24 weeks differed significantly from the baseline values only in those patients who reached an ACR70 level （P 〈0.05）.Conclusions Measurement of serum TRACP-5b in RA patients reflects clinical and radiological measures of disease activity,treatment with certain biologics,and degree of response to therapy.TRACP-5b should be investigated further as a potential biomarker to predict response to therapy,including slowing of radiographic progression.

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.

The discovery of the fat-regulating phosphatidic acid phosphatase gene

Phosphatidic acid phosphatase is a fat-regulating enzyme that plays a major role in controlling the balance of phosphatidic acid(substrate)and diacylglycerol(product),which are lipid precursors used for the synthesis of membrane phospholipids and triacylglycerol.Phosphatidic acid is also a signaling molecule that triggers phospholipid synthesis gene expression,membrane expansion,secretion,and endocytosis.While this important enzyme has been known for several decades,its gene was only identified recently from yeast.This discovery showed the importance of phosphatidic acid phosphatase in lipid metabolism in yeast as well as in higher eukaryotes including humans.

Effect of noise exposure(85 dB) on testicular adrenocortical steroidogenic key enzymes, acid and alkaline phosphatase activities of sex organs in mature albino rats

Changes in the activities of Δ 5\|3β\|hydroysteroid dehydrogenase(HSD) in testis and adrenal gland, 17β\|hydroxysteroid dehydrogenase in testis, acid and alkaline phosphatase in testis, prostate and seminal vesicle were observed in noise exposed mature rats at the intensity of 85 dB for 8 h/day for 45 days. The results indicated that noise exposed group showed a significant diminution in the activities of androgenic key enzymes Δ 5\|3β and 17β\|HSD, acid phosphatase in testis, prostate and seminal vesicle. There was a significant elevation in the activities of adrenal Δ 5\|3β\|HSD, alkaline phosphatase in testis and other accessory sex organ in noise exposed group. Gonadosomatic, prostatosomatic and seminal vesiculo\|somatic indexes were decreased significantly in noise exposed group. Therefore, it is evident that noise exposure at 85dB exerts a deleterious effect on testicular and adrenocortical activities.

In situ growth of polydopamine on surface of covalent organic frameworks under the catalysis of acid phosphatase for dopamine detection

Dopamine(DA)is easy to be oxidized and polymerizes to form polydopamine(pDA)in alkaline conditions,while the synthesis is usually time-consuming(48 h).Herein,the polymerization of DA is completed with 4 h under the catalysis of acid phosphatase(ACP).The high efficiency makes the detection of DA feasibility based on the self-polymerization of DA.In this assay,pDA is grown in situ on the surface of covalent organic frameworks(COFs),and then the fluorescence of COFs is quenched significantly.The linear range of DA is achieved from 0.5-50μmol/L with a detection limit of 0.16μmol/L.The detection of DA is not interfered with uric acid,ascorbic acid,and some phenolic compounds,because these substances cannot polymerize in the presence of ACP.Moreover,benefiting from the good sensitivity and selectivity,DA has been successfully determined by this strategy in human urine samples with satisfactory recoveries.

A MALDI-MS sensing chip prepared by non-covalent assembly for quantitation of acid phosphatase

A novel sensing chip was designed for MALDI-MS quantitation of acid phosphatase(ACP).The ACP sensing chip was constructed through non-covalent interaction of streptavidin and biotin for the assembly of biotinylated peptide substrate on biotinylated polyethylene-glycol(PEG)modified indium-tin oxide(ITO)slide.In the presence of ACP,the peptide substrate was dephosphorylated under acidic condition to generate a new mass signal.The quantitative assay of ACP was achieved with the mass signal ratio of product to the sum of product and left peptide substrate.Under optimal detection conditions,the ratio was linearly correlated with the concentration of ACP in the range of 0.05–12 g/L with a detection limit(LOD)of 0.04 g/L.The designed ACP sensing chip has been used to analyze ACP in complex clinical samples,which exhibited high selectivity,good repeatability,and admirably anti-interference ability.This work further demonstrates the concept of MS sensing and the application of MALDI-MS in quantitative analysis,and provides a convenient method for the quantitation of proteases in clinical diagnosis.

Inhibition of Model Compound of Purple Acid Phosphatases on Growth of Aerobacter aerogenes Investigated by Microcalorimetry

Microcalorimetry was used to study the inhibitory or antibiotic action of six kinds of the model compounds of purple acid phosphatases on a strain of Aerobacter aerogenes . Difference in their capacities to inhibit the metabolism of this bacterium was observed. The extent and duration of the inhibitory effect on the metabolism as judged from the growth rate constant, k , and the half inhibitory concentration, IC 50 , varied with the different drugs. The rate constant k of A. aerogenes (in the log phase) in the presence of the compounds decreased with the increasing of concentrations. The experimental results reveal that the order of the antibiotic activity of the compounds is: LD 1>LD 2>LD 3>XF 1>LD 4～LD 5.

Partial Purification and Properties of an Acid Phosphatase from Pearl Oyster Pinctada Fucata

Acid phosphatases (ACPs) are marker enzymes for the detection of lysosomes in cell fractions. However, ACPs in sea creatures are less studied than those on land. An acid phosphatase was partially purified from pearl oyster Pinctada fucata by chromatography on Sephadex G 150 and Con A Sepharose 4B. The specific activity was 1719 U·mg -1 and with optimum pH (5.0) and temperature (60℃). The enzyme was strongly inhibited competitively by product analog WO 3- 4 and MoO 3- 4, but less inhibited by product analog AsO 3- 4. The enzyme could also be strongly inhibited by heavy metal ions, such as Ag + and Cu 2+ , but was not affected by Pb 2+ . High concentrations of ethanol (64%) and NaF (10 -3 mol·L -1 ) could inhibit the enzyme while low concentration of NaF (<10 -4 mol·L -1 ) could slightly activate the enzyme. Other haloids (Cl -, Br -, I -) and EDTA did not have any effect on this enzyme, while tartrate and some chemical modification reagents (bromoacetic acid, formaldehyde and dithiothreitol) could inhibit the enzyme. It is concluded that the properties of the enzyme are different from many fresh water mollusks.

Acid-Phosphorus Activity of Wheat Varieties Rhizobacteria of Uzbekistan

In this work, local strains of phosphate-solubilizing microorganisms were isolated and identified from the wheat rhizosphere and exogenous acid phosphatase enzymes of locally active phosphate- and potassium-mobilizing rhizobacteria belonging to the genera Escherichia, Rahnella, Bacillus, Enterobacter, Pseudomonas, and Pantoea were studied. The efficiency of the physiological properties of rhizobacteria is determined by the production of soluble phosphorus, and the amount of phosphorus depends on the activity and biomass of bacteria that secrete phosphorus. This is done by phosphate solubilizing bacteria, and the habitat ecosystem is enriched with beneficial micronutrients. In these studies, active rhizobacteria activity of acid phosphatase in nutrient liquid was studied at different temperatures. Optimum pH activity index and temperature variability of enzymes were determined. It should be noted that in the most active phosphate-solubilizing strains the maximum enzymatic activity was observed in the culture fluid of R. aquatilis strain 17, which produced 1.086 μmol p-nitrophenol μmol/min/ml. P. agglomerans 22, P. agglomerans 20 and Ps. kilonensis 32 cultures phosphatase activity was 0.143 - 0.680 p-nitrophenol μmol/min/ml. It should be noted that the phosphatase activity of bacteria belonging to the same genus and species was very different from each other. That is, the enzyme activity of Rahnella aquatilis strain 17 was 9 times higher than the enzyme activity of Rahnella aquatilis strain 9. The pH optimum of sour phosphatase enzymes in Rahnella aquatilis strain 16 was 6.0. The optimum temperature of acid phosphatase activity was 45˚C and 50˚C. The reason for this may be that the strains were isolated in different soil and climate conditions. When the acid phosphatase activity of R. aquatilis 3, 9, E. cloacae 8 and P. agglomerans 22 cultures was determined at a temperature of 45˚C, it was observed that the enzyme activity increased by 2 - 4 times. Es. hermannii 1, Ps. kilonensis 26 and B. simplex 28 bacteria acid phosphatase activity was not significantly affected by temperature rise.

Identification of an Mg2+-Independent Soluble Phosphatidate Phosphatase in Cottonseed (Gossypium hirsutum L.)

Cotton (Gossypium hirsutum L.) provides a major source of oil for food and feed industries, but little was known about the enzymes in the oil biosynthesis pathway in cottonseed. We are interested in a better understanding of enzymatic components for oil accumulation in cottonseed. The objective of this study was to identify one key enzyme in oil biosynthesis pathway: phosphatidic acid phosphatase (PAP, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4). PAP hydrolyzes the phosphomonoester bond in phosphatidate yielding diacylglycerol and Pi. PAPs are generally categorized into Mg2+-dependent soluble PAP and Mg2+-independent membrane-associated PAP. Cottonseed from 25 - 30 days post anthesis was used for the study. The results showed that an Mg2+-independent soluble PAP activity was identified from the cottonseed. While the microsomal fraction of the extract provided only 9% of the PAP activity, 69% of the PAP activity was associated with the cytosol. The PAP activity correlated well with enzyme concentration and incubation time. The pH and temperature optima of the enzyme were pH 5 and 55℃, respectively. Under optimized assay conditions, the Vmax and Km values of cottonseed PAP for dioleoyl phosphatidic acid as the substrate were 2.8 nkat/mg of protein and 539 μM, respectively. Inclusion of the detergent Triton X-100 (0% - 0.5%) or magnesium chloride (1 mM) in the reaction mix did not alter activity to a significant degree. This is the first report of a PAP activity in the seeds of Gossipium hirsutum. This study should provide a basis for purification and characterization of this important enzyme from cottonseed in the future.

Utilizing zebrafish and okadaic acid to study Alzheimer's disease

Despite the many years of extensive research using rodent models to study Alzheimer＇s disease （AD）, no cure or disease halting drug exists. An increasing number of people are suffering from the disease and a therapeutic intervention is needed. Therefore, it is necessary to have complementary models to aid in the drug discovery. The zebrafish animal model is emerging as a valuable model for the investigation of AD and neurodegenerative drug discovery. The main genes involved in human AD have homologous counter- parts in zebrafish and have conserved function. The basic brain structure of the zebrafish is also conserved when compared to the mammalian brain. Recently an AD model was established by administering okadaic acid to zebrafish. It was used to test the efficacy of a novel drug, lanthionine ketimine-5-ethyl ester, and to elucidate its mechanism of action. This demonstrated the ability of the okadaic acid-induced AD zebrafish model to be implemented in the drug discovery process for therapeutics against AD.