Characterization of a novel acid phosphatase from embryonic axes of kidney bean exhibiting vanadate-dependent chloroperoxidase activity

Isolation and biochemical characterization of novel acid phosphatase and zinc-dependent acid phosphatase from the chicken's brain

The AcPase exhibits a specific activity of 31.32 U/mg of protein with a 728-fold purification, and the yield of the enzyme is raised to 3.15 %. The Zn2+-dependent AcPase showed a purification factor of 1.34 specific activity of 14 U/mg of proteins and a total recovery of 5.14. The SDS-PAGE showed a single band corresponding to a molecular weight of 18 kDa of AcPase and 29 kDa of Zn2+-dependent AcPase. The AcPase enzyme has shown a wide range of substrate specificity for p-NPP, phenyl phosphate and FMN, while in the case of ZnAcPase α and β-Naphthyl phosphate and p-NPP were proved to be superior substrates. The divalent metal ions like Mg2+, Mn2+, and Ca2+ increased the activity, while other substrates decreased the enzyme activity. The Km (0.14 mM) and Vmax (21 μmol/min/mg) values of AcPase were higher than those of Zn2+-AcPase (Km = 0.5 mM; Vmax = 9.7 μmol/min/mg). The Zn2+ ions activate the Zn2+-AcPase while Fe3+, Al3+, Pb2+, and Hg2+ showed inhibition on enzyme activity. Molybdate, vanadate and phosphate were found to be competitive inhibitors of AcPase with Ki values 316 μM, 185 μM, and 1.6 mM, while in Zn2+-AcPase tartrate and phosphate also showed competitive inhibition with Ki values 3 mM and 0.5 mM respectively.

Kinetic and thermodynamic studies of novel acid phosphates extracted from Cichorium intybus seedlings

Herein for the first time a novel acid phosphatase from the seedlings of Cichorium intybus was purified to homogeneity by using various chromatographic techniques (salt precipitation, ion exchange, size exclusion and affinity chromatography) and thermodynamically characterized. The molecular mass of purified enzyme (66 kDa) was determined by SDS-PAGE under denaturing and non-denaturing conditions and by gel-filtration confirmed as dimer of molecular mass 130 kDa. The Michaelis-Menten (Km) constant for -p-NPP (0.3 mM) and (7.6 μmol/min/mg) Vmax. The enzyme was competitively inhibited by phosphate, molybdate and vanadate. Phenyl phosphate, ɑ and β-glycero-phosphate and-p-NPP were found to be good substrate. When temperature increased from (55 °C to 75 °C), the deactivation rate constant (kd) was increased (0.1 to 4.6 min-1) and half- life was decreased from 630 min to 15 min. Various thermal denaturation parameters; change in enthalpy (ΔH°), change in entropy (ΔS°) and change in free energy (ΔG°) were found 121.93 KJ·mol-1, 72.45 KJ·mol-1 and 98.08 KJ·mol-1 respectively, confirming that acid phosphatase undergoes a significant process of unfolding during deactivation. The biochemical properties of acid phosphatase from C. intybus on the behalf of biological activity and its relationship to pH variations, thermal deactivation and kinetics parameters provide an insight into its novel features.

Sulfated Purine Alkaloid Glycosides from the Pupal Case Built by the Bruchid Beetle Bruchidius dorsalis Inside the Seed of Gleditsia japonica

Three new sulfated isoguanine alkaloid glycosides, designated as saikachinoside A monosulfate (1), saikachinoside A disulfate (2), and locustoside B disulfate (3), have been isolated from the pupal case of the wild bruchid seed beetle Bruchidius dorsalis (Chrysomelidae, Bruchinae) infesting the seed of Gleditsia japonica Miq. (Fabaceae). Their structures were determined by spectroscopic methods and the inhibitory activity of 2 and 3 against acid phosphatase was evaluated.

The role of microorganisms in the degradation of adenosine triphosphate (ATP) in chill-stored common carp (Cyprinus carpio) fillets

Biochemical and microbial changes after harvest strongly affect the final quality and shelf life of fish and fish products. In this study, the role of microbes in the degradation of adenosine triphosphate (ATP), and the origin of adenosine monophosphate deaminase (AMPD) and acid phosphatase (ACP) in common carp fillets during different stages of chilled storage (at 4°C) were investigated. The content of ATP, ADP, AMP, IMP, HxR, and Hx, the activity of AMPD and ACP, and the total count of viable, Aeromonas, Pseudomonas, H₂S-producing bacteria, and lactic acid bacteria were examined. Results indicated that the population of microbial communities in control samples increased with storage time, and Pseudomonas peaked on the 10th day of storage. Changes in AMPD activity were less related to the abundance of microbes during the entire storage period. However, ACP was derived from both fish muscle and microbial secretion during the middle and late stages of storage. Degradation of ATP to IMP was not affected by spoilage bacteria, but the hydrolysis of IMP, and the transformation of HxR to Hx was affected considerably by the spoilage bacteria.

Gene expression profiles in testis of developing male Xenopus laevis damaged by chronic exposure of atrazine

As a widely used herbicide, atrazine (AZ) has been extensively studied for its adverse effects on the reproductive system, especially feminization in male animals. However, the relationship of gene expression changes and associated toxicological endpoints remains unclear. In this study, developing Xenopus laevis tadpoles were exposed to concentration of AZ at 0.1, 1, 10 or 100 μg/L continuously. Compared with froglets in the control group, there were no significant differences in body length, body weight, liver weight and hepatosomatic index (HSI) of males in groups treated with AZ for 90 d. At 100 μg/L AZ treatment caused a significant reduction of gonad weight and gonadosomatic index (GSI) of males (p < 0.01). In addition, AZ at all dose levels caused testicular degeneration, especially in froglets from the groups with 0.1 and 100 μg/L which exhibited U-shaped dose-response trend. We further investigated the gene expression changes associated with the testicular degeneration induced by AZ. We found that the expression of 1165 genes was significantly altered with 616 upregulated and 549 downregulated compared to the expression profile of the control animals. KEGG analysis showed that genes which were significantly affected by AZ are mainly involved in arginine and proline metabolism, cell cycle, riboflavin metabolism, spliceosome, base excision repair and progesterone-mediated oocyte maturation pathway. Our results show that AZ may affect reproductive and immune systems by interference with the related gene expression changes during the male X. laevis development. The findings may help to clarify the feminization mechanisms of AZ in male X. laevis.

Identification and characterization of a gene encoding for a nucleotidase from Phaseolus vulgaris

Nucleotidases are phosphatases that catalyze the removal of phosphate from nucleotides, compounds with an important role in plant metabolism. A phosphatase enzyme, with high affinity for nucleotides monophosphate previously identified and purified in embryonic axes from French bean, has been analyzed by MALDI TOF/TOF and two internal peptides have been obtained. The information of these peptide sequences has been used to search in the genome database and only a candidate gene that encodes for the phosphatase was identified (PvNTD1). The putative protein contains the conserved domains (motif I-IV) for haloacid dehalogenase-like hydrolases superfamily. The residues involved in the catalytic activity are also conserved. A recombinant protein overexpressed in Escherichia coli has shown molybdate resistant phosphatase activity with nucleosides monophosphate as substrate, confirming that the identified gene encodes for the phosphatase with high affinity for nucleotides purified in French bean embryonic axes. The activity of the purified protein was inhibited by adenosine. The expression of PvNTD1 gene was induced at the specific moment of radicle protrusion in embryonic axes. The gene was also highly expressed in young leaves whereas the level of expression in mature tissues was minimal.

The Effects of Simazine, a Chlorotriazine Herbicide, on the Expression of Genes in Developing Male Xenopus laevis

Simazine was investigated for gene expression concurrent with simazine-induced phenotype changes during development of male Xenopus laevis. X. laevis tadpoles (Nieuwkoop-Faber stage 46) were exposed to 0.1, 1.2, 11.0 and 100.9 μg/L simazine for 100 days. The results showed that an increased mortality of X. laevis, decreased gonad weight and altered gonadosomatic index of males significantly (p<0.05) when exposed to simazine at 11.0 and 100.9 µg/L. Significant degeneration in testicular tissues was observed when tadpoles were exposed to simazine at 100.9 µg/L. To investigate the molecular mechanisms behind the testicular degeneration by simazine, we evaluated gene expression in animals treated with 100.9 µg/L simazine and found that 1,315 genes were significantly altered (454 upregulated, 861 downregulated). Genes involved in the cell cycle control, and amino acid metabolism pathways were significantly downregulated. These results indicate that simazine affects the related gene expressions which may be helpful for the understanding of the reason for the reproductive toxicity of simazine on male X. laevis.

The role of vanadium in biology

Vanadium is special in at least two respects: on the one hand, the tetrahedral anion vanadate(v) is similar to the phosphate anion; vanadate can thus interact with various physiological substrates that are otherwise functionalized by phosphate. On the other hand, the transition metal vanadium can easily expand its sphere beyond tetrahedral coordination, and switch between the oxidation states +v, +iv and +iii in a physiological environment. The similarity between vanadate and phosphate may account for the antidiabetic potential of vanadium compounds with carrier ligands such as maltolate and picolinate, and also for vanadium's mediation in cardiovascular and neuronal defects. Other potential medicinal applications of more complex vanadium coordination compounds, for example in the treatment of parasitic tropical diseases, may also be rooted in the specific properties of the ligand sphere. The ease of the change in the oxidation state of vanadium is employed by prokarya (bacteria and cyanobacteria) as well as by eukarya (algae and fungi) in respiratory and enzymatic functions. Macroalgae (seaweeds), fungi, lichens and Streptomyces bacteria have available haloperoxidases, and hence enzymes that enable the 2-electron oxidation of halide X(-) with peroxide, catalyzed by a Lewis-acidic V(V) center. The X(+) species thus formed can be employed to oxidatively halogenate organic substrates, a fact with implications also for the chemical processes in the atmosphere. Vanadium-dependent nitrogenases in bacteria (Azotobacter) and cyanobacteria (Anabaena) convert N2 + H(+) to NH4(+) + H2, but are also receptive for alternative substrates such as CO and C2H2. Among the enigmas to be solved with respect to the utilization of vanadium in nature is the accumulation of V(III) by some sea squirts and fan worms, as well as the purport of the nonoxido V(IV) compound amavadin in the fly agaric.

A phosphoenol pyruvate phosphatase transcript is induced in the root nodule cortex of Phaseolus vulgaris under conditions of phosphorus deficiency

Although previous studies on N2-fixing legumes have demonstrated the contribution of acid phosphatases to their phosphorus (P) use efficiency under P-deficient growth conditions, localization of these enzymes in bean nodules has not been demonstrated. In this study, phosphoenol pyruvate phosphatase (PEPase) gene transcripts were localized within the nodule tissues of two recombinant inbred lines, RIL115 (P-deficiency tolerant) and RIL147 (P-deficiency sensitive), of Phaseolus vulgaris. Nodules were induced by Rhizobium tropici CIAT899 under hydroaeroponic conditions with a sufficient versus a deficient P supply. The results indicated that PEPase transcripts were particularly abundant in the nodule infected zone and cortex of both RILs. Analysis of fluorescence intensity indicated that nodule PEPase was induced under conditions of P deficiency to a significantly higher extent in RIL147 than in RIL115, and more in the inner cortex (91%) than in the outer cortex (71%) or the infected zone (79%). In addition, a significant increase (39%) in PEPase enzyme activity in the P-deficient RIL147 correlated with an increase (58%) in the efficiency of use in rhizobial symbiosis. It was concluded that nodule PEPase is upregulated under conditions of P deficiency in the P-deficiency-sensitive RIL147, and that this gene may contribute to adaptation of rhizobial symbiosis to low-P environments.

A molecular description of acid phosphatase

Acid phosphatase is ubiquitous in distribution in various organisms. Although it catalyzes simple hydrolytic reactions, it is considered as an interesting enzyme in biological systems due to its involvement in different physiological activities. However, earlier reviews on acid phosphatase reveal some fragmentary information and do not give a holistic view on this enzyme. So, the present review summarizes studies on biochemical properties, structure, catalytic mechanism, and applications of acid phosphatase. Recent advancement of acid phosphatase in agricultural and clinical fields is emphasized where it is presented as potent agent for sustainable agricultural practices and diagnostic marker in bone metabolic disorders. Also, its significance in prostate cancer therapies as a therapeutic target has been discussed. At the end, current studies and prospects of immobilized acid phosphatase are included.

Comparative analysis of PvPAP gene family and their functions in response to phosphorus deficiency in common bean

BACKGROUND

Purple acid phosphatases (PAPs) play a vital role in adaptive strategies of plants to phosphorus (P) deficiency. However, their functions in relation to P efficiency are fragmentary in common bean.

PRINCIPAL FINDINGS

Five PvPAPs were isolated and sequenced in common bean. Phylogenetic analysis showed that PvPAPs could be classified into two groups, including a small group with low molecular mass, and a large group with high molecular mass. Among them, PvPAP3, PvPAP4 and PvPAP5 belong to the small group, while the other two belong to the large group. Transient expression of 35S:PvPAPs-GFP on onion epidermal cells verified the variations of subcellular localization among PvPAPs, suggesting functional diversities of PvPAPs in common bean. Quantitative PCR results showed that most PvPAPs were up-regulated by phosphate (Pi) starvation. Among them, the expression of the small group PvPAPs responded more to Pi starvation, especially in the roots of G19833, the P-efficient genotype. However, only overexpressing PvPAP1 and PvPAP3 could result in significantly increased utilization of extracellular dNTPs in the transgenic bean hairy roots. Furthermore, overexpressing PvPAP3 in Arabidopsis enhanced both plant growth and total P content when dNTPs were supplied as the sole external P source.

CONCLUSIONS

The results suggest that PvPAPs in bean varied in protein structure, response to P deficiency and subcellular localization. Among them, both PvPAP1 and PvPAP3 might function as utilization of extracellular dNTPs.

Biochemical and molecular characterization of PvPAP3, a novel purple acid phosphatase isolated from common bean enhancing extracellular ATP utilization

Purple acid phosphatases (PAPs) play diverse physiological roles in plants. In this study, we purified a novel PAP, PvPAP3, from the roots of common bean (Phaseolus vulgaris) grown under phosphate (Pi) starvation. PvPAP3 was identified as a 34-kD monomer acting on the specific substrate, ATP, with a broad pH range and a high heat stability. The activity of PvPAP3 was insensitive to tartrate, indicating that PvPAP3 is a PAP-like protein. Amino acid sequence alignment and phylogenetic analysis suggest that PvPAP3 belongs to the group of plant PAPs with low molecular mass. Transient expression of 35S:PvPAP3-green fluorescent protein in onion (Allium cepa) epidermal cells verified that it might anchor on plasma membrane and be secreted into apoplast. Pi starvation led to induction of PvPAP3 expression in both leaves and roots of common bean, and expression of PvPAP3 was strictly dependent on phosphorus (P) availability and duration of Pi starvation. Furthermore, induction of PvPAP3 expression was more rapid and higher in a P-efficient genotype, G19833, than in a P-inefficient genotype, DOR364, suggesting possible roles of PvPAP3 in P efficiency in bean. In vivo analysis using a transgenic hairy root system of common bean showed that both growth and P uptake of bean hairy roots from the PvPAP3 overexpression transgenic lines were significantly enhanced when ATP was supplied as the sole external P source. Taken together, our results suggest that PvPAP3 is a novel PAP that might function in the adaptation of common bean to P deficiency, possibly through enhancing utilization of extracellular ATP as a P source.

Expression and characterization of a recombinant unique acid phosphatase from kidney bean hypocotyl exhibiting chloroperoxidase activity in the yeast pichia pastoris

We previously purified and characterized a novel acid phosphatase (KhACP) from kidney bean hypocotyls that exhibited vanadate-dependent chloroperoxidase (V-CPO) activity. In the present study, a functional recombinant KhACP (rKhACP) was successfully produced at a high expression level by the methylotrophic yeast Pichia pastoris. The KhACP cDNA excising signal peptide sequence was subcloned into the pPICZalphaA vector and then integrated into the genome of P. pastoris strain X-33 under control of the alcohol oxidase 1 promoter. The rKhACP protein, with a molecular mass of 60 kDa on SDS-PAGE, was secreted into the culture medium as a C-terminal His-tagged fusion protein. Purification was facile using only nickel affinity chromatography. The apparent molecular mass of the purified rKhACP was estimated to be around 110 kDa by analytical gel filtration. PAGE analysis showed that rKhACP was a glycosylated dimeric enzyme, consisting of two 60-kDa subunits linked non-covalently, which was similar to the dominant form of the natural enzyme isolated from plant material. Furthermore, the rKhACP exhibited V-CPO activity when ortho-vanadate (VO4(3-)) was added to the apo enzyme, and it showed broad substrate specificity and kinetic parameters comparable to the natural enzyme. This expression system produces sufficient protein to allow us to attempt to determine the three-dimensional crystal structure, which will shed light on its unique mechanism of converting KhACP to vanadate-dependent chloroperoxidase.

Cloning and sequencing of cDNA and genomic DNA encoding PDM phosphatase of Fusarium moniliforme

PDM phosphatase was purified approximately 500-fold through six steps from the extract of dried powder of the culture filtrate of Fusarium moniliforme. The purified preparation appeared homogeneous on SDS-PAGE although the protein band was broad. Amino acid sequence information was collected on tryptic peptides from this preparation. cDNA cloning was carried out based on the information. A full-length cDNA was obtained and sequenced. The sequence had an open reading frame of 651 amino acid residues with a molecular mass of 69,988 Da. Cloning and sequencing of the genomic DNA corresponding to the cDNA was also conducted. The deduced amino acid sequence could account for many but not all of the tryptic peptides, suggesting presence of contaminant protein(s). SDS-PAGE analysis after chemical deglycosylation showed two proteins with molecular masses of 58 and 68 kDa. This implied that the 58 kDa protein had been copurified with PDM phosphatase. Homology search showed that PDM phosphatase belongs to the purple acid phosphatase family, which is widely distributed in the biosphere. Sequence data of fungal purple acid phosphatases were collected from the database. Processing of the data revealed presence of two types, whose evolutionary relationships were discussed.

Tick pheromones and their use in tick control

Tick pheromones that regulate assembly, attraction/aggregation/attachment, and mating behavior have been described. Most of the compounds regulating these behaviors are purines, substituted phenols, or cholesteryl esters. Other pheromonal compounds include organic acids, hematin, or ecdysteroids. Novel devices have been developed that combine the specific compounds comprising these pheromones with an acaricide. When applied to tick-infested vegetation or directly to the body surfaces of livestock or companion animals, these devices are effective for tick control. This review summarizes the current state of knowledge of tick pheromones. In addition, this review also presents examples illustrating how devices using tick pheromones can offer effective alternatives to conventional methods for achieving tick control.