High Acid Phosphatase Activity Research Articles

Influence of triethyl phosphate on phosphatase activity in shooting range soil: Isolation of a zinc-resistant bacterium with an acid phosphatase

Phosphatase-mediated hydrolysis of organic phosphate may be a viable means of stabilizing heavy metals via precipitation as a metal phosphate in bioremediation applications. We investigated the effect of triethyl phosphate (TEP) on soil microbial-phosphatase activity in a heavy-metal contaminated soil. Gaseous TEP has been used at subsurface sites for bioremediation of organic contaminants but not applied in heavy-metal contaminated areas. Little is known about how TEP affects microbial activity in soils and it is postulated that TEP can serve as a phosphate source in nutrient-poor groundwater and soil/sediments. Over a 3-week period, TEP amendment to microcosms containing heavy-metal contaminated soil resulted in increased activity of soil acid-phosphatase and repression of alkaline phosphatase, indicating a stimulatory effect on the microbial population. A soil-free enrichment of microorganisms adapted to heavy-metal and acidic conditions was derived from the TEP-amended soil microcosms using TEP as the sole phosphate source and the selected microbial consortium maintained a high acid-phosphatase activity with repression of alkaline phosphatase. Addition of 5mM zinc to soil-free microcosms had little effect on acid phosphatase but inhibited alkaline phosphatase. One bacterial member from the consortium, identified as Burkholderia cepacia sp., expressed an acid-phosphatase activity uninhibited by high concentrations of zinc and produced a soluble, indigo pigment under phosphate limitation. The pigment was produced in a phosphate-free medium and was not produced in the presence of TEP or phosphate ion, indicative of purple acid-phosphatase types that are pressed by bioavailable phosphate. These results demonstrate that TEP amendment was bioavailable and increased overall phosphatase activity in both soil and soil-free microcosms supporting the possibility of positive outcomes in bioremediation applications.

Activity and functional diversity of microbial communities in long-term hydrocarbon and heavy metal contaminated soils

AbstractThe impacts of long-term polycyclic aromatic hydrocarbons (PAHs) and heavy metal pollution on soil microbial communities functioning were studied in soils taken from an old coke plant. The concentrations of PAHs in the tested soils ranged from 171 to 2137 mg kg-1. From the group of tested heavy metals, concentrations of lead were found to be the highest, ranging from 57 to 3478 mg kg-1, while zinc concentrations varied from 247 to 704 mg kg-1and nickel from 10 to 666 mg kg-1. High dehydrogenase, acid and alkaline phosphatase activities were observed in the most contaminated soil. This may indicate bacterial adaptation to long-term heavy metal and hydrocarbon contamination. However, the Community Level Physiological Profiles (CLPPs) analysis showed that the microbial functional diversity was reduced and influenced to a higher extent by some metals (Pb, Ni), moisture and conductivity than by PAHs.

Phosphate dissolving fungi: Mechanism and application in alleviation of salt stress in wheat

The present investigation reveals the solubilization efficiency of tri-calcium phosphate (TCP), Udaipur rock phosphate (URP), aluminium phosphate (AP) and ferric phosphate (FP) by Aspergillus niger (ITCC 6719) and Trichoderma harzianum (ITCC 6721) as function of carbon concentrations. Increasing glucose concentration from 1 to 7% in the growth medium, though improved the phosphorus (P) solubilization significantly but each fungal strain preferred different optimum carbon concentrations for mediating solubilization of different P sources. The two fungi employed different mechanisms to reduce medium pH for release of P from TCP, AP and FP. However, URP was solubilized solely through fungal production of citric, succinic, propionic, malic and acetic acid. A linear increase in citric acid production with increasing carbon concentration was recorded during FP solubilization by T. harzianum. The cell free culture filtrate of A. niger detected high phytase and low acid phosphatase activity titre whereas results were vice versa for T. harzianum. Both the fungal strains possessed plant growth promoting attributes such as auxin and sidreophore production and could solubilize Zn. In hydroponic system (with 60mM of sodium chloride concentration), supplementation with culture filtrate from each fungal strain increased the shoot growth of wheat seedlings significantly compared to non culture filtrate control. Use of A.niger as bio-inoculant could be a sustainable approach to improve soil P availability, promote plant growth and alleviate adverse effect of salt stress.

Transcriptional, translational, and physiological signatures of undernourished honey bees (Apis mellifera) suggest a role for hormonal factors in hypopharyngeal gland degradation

Honey bee colonies function as a superorganism, where facultatively sterile female workers perform various tasks that support the hive. Nurse workers undergo numerous anatomical and physiological changes in preparation for brood rearing, including the growth of hypopharyngeal glands (HGs). These glands produce the major protein fraction of a protein- and lipid-rich jelly used to sustain developing larvae. Pollen intake is positively correlated with HG growth, but growth in the first three days is similar regardless of diet, suggesting that initial growth is a pre-determined process while later HG development depends on nutrient availability during a critical window in early adulthood (>3d). It is unclear whether the resultant size differences in nurse HG are simply due to growth arrest or active degradation of the tissue. To determine what processes cause such differences in HG size, we catalogued the differential expression of both gene transcripts and proteins in the HGs of 8d old bees that were fed diets containing pollen or no pollen. 3438 genes and 367 proteins were differentially regulated due to nutrition. Of the genes and proteins differentially expressed, undernourished bees exhibited more gene and protein up-regulation compared to well-nourished bees, with the affected processes including salivary gland apoptosis, oogenesis, and hormone signaling. Protein secretion was virtually the only process up-regulated in well-nourished bees. Further assays demonstrated that inhibition of ultraspiracle, one component of the ecdysteroid receptor, in the fat body caused larger HGs. Undernourished bees also had higher acid phosphatase activity, a physiological marker of cell death, compared to well-nourished bees. These results support a connection between poor nutrition, hormonal signaling, and HG degradation.

Effects of dietary rhubarb, Bacillus cereus, yeast polysaccharide, and florfenicol supplementation on growth, intestinal morphology, and immune responses of sea cucumber (Apostichopus japonicus)

A 60-day feeding trial was conducted to investigate the effects of dietary Chinese herbal medicine (rhubarb, Rheum officinale Bail), probiotic (Bacillus cereus BC-01), prebiotic (yeast polysaccharide), and antibiotic (florfenicol) supplementation on the growth, intestinal morphology, and immune responses of juvenile sea cucumbers (Apostichopus japonicus Selenka; initial weight, 4.67 ± 0.06 g). The control treatment was fed only the basal diet (CT treatment), whereas four other treatments were fed the basal diet supplemented with rhubarb (RH treatment), B. cereus BC-01 (BC treatment), yeast polysaccharide (PO treatment), or florfenicol (FL treatment). Groups of ten sea cucumbers were housed in separate tanks, and each diet was fed to five randomly selected groups. The specific growth rates of the individuals in the RH and BC treatments were significantly higher than those in the CT, PO, and FL treatments. The apparent digestibility coefficient of crude protein in the RH and BC treatments was significantly higher than that of crude protein in the CT and PO treatments. The alkaline phosphatase activity of the coelomocytes in the RH and BC treatments was significantly higher than that in the CT and FL treatments. Coelomocytes in the PO treatment had the highest acid phosphatase activity. Higher than average lysozyme activity was observed in the PO and FL treatments. Fold and enterocyte heights in the mid-intestinal tract of sea cucumbers in the CT and RH treatments were lower than those in the BC, PO, and FL treatments. Microvillus height was greatest in the RH treatment and lowest in the FL treatment. Scanning electron microscopy revealed remarkable atrophy of microvilli and apoptosis of intestinal epithelial cells in the FL treatment. These results suggest that dietary rhubarb, B. cereus, and yeast polysaccharide supplementation can improve the health of sea cucumbers, whereas long-term florfenicol supplementation may have a negative impact on their intestinal healthy and immune response of sea cucumbers.

Carbon and Nitrogen Sources Influence Tricalcium Phosphate Solubilization and Extracellular Phosphatase Activity by Talaromyces flavus.

The aim of this work was to study phosphate (P) solubilization (and the processes involved in this event) by Talaromyces flavus (BAFC 3125) as a function of carbon and/or nitrogen sources. P solubilization was evaluated in NBRIP media supplemented with different carbon (glucose, sorbitol, sucrose, and fructose) and nitrogen (L-asparagine, urea, ammonium sulfate (AS), and ammonium nitrate (AN) combinations. The highest P solubilization was related to the highest organic acid production (especially gluconic acid) and pH drop for those treatments where glucose was present. Also P solubilization was higher when an inorganic nitrogen source was supplemented to the media when compared to an organic one. Although not being present an organic P source, phosphatase activity was observed. This shows that P mineralization and P solubilization can occur simultaneously, and that P mineralization is not induced by the enzyme substrate. The combination that showed highest P solubilization was for AN-glucose. The highest acid phosphatase activity was for AS-fructose, while for alkaline phosphatase were for AS-fructose and AN-fructose. Acid phosphatase activity was higher than alkaline. P solubilization and phosphatase activity (acid and alkaline) were influenced by the different carbon-nitrogen combinations. A better understanding of phosphate-solubilizing fungi could bring a better use of soil P.

Assessment of the influence of composts on microbiological and biochemical parameters of substrates and the morphological traits of scarlet sage / Ocena wpływu kompostów na parametry mikrobiologiczne i biochemiczne podłoży oraz cechy morfologiczne szałwii błysz czącej

Abstract The aim of the research was to assess the microbiological (number of heterotrophic bacteria, actinobacteria and moulds) and biochemical (urease and acid phosphatase activity) state of peat with the admixture of composts produced from sewage sludge. An additional aim of the research was to demonstrate the influence of those substrates on the morphological traits of scarlet sage (height, number and length of shoots, number of buds and inflorescences, greenness index (SPAD)). Composts produced from sewage sludge, wheat, maize and lupine straw were mixed with peat, where their percentage varied from 25% to 75%. The substrate which included the composts applied in the experiment had a higher number of heterotrophic bacteria and a higher acid phosphatase activity level than the control substrate (peat). The multiplication of moulds and actinobacteria was more intensive than in the peat only in the combinations with K3 (sewage sludge 50%+sawdust 20%+ lupine straw 30%) and K4 (sewage sludge 50%+sawdust 20%+fresh maize straw 30%) composts, whereas the highest urease activity level was observed in the soils produced from K1 (sewage sludge 50%+sawdust 20%+white straw 30%) compost. The most optimal development of plants was observed in the substrate with compost produced from wheat straw. Composts produced from municipal sewage sludge were found to be suitable for growing scarlet sage. However, their effect depends on the percentage of high peat in the substrate.

Soil bacterial community response to sulfadiazine in the soil–root zone

AbstractSulfonamide antibiotics reach soil via manure and adversely affect microbial diversity. Clear effects of these bacteriostatic, growth‐inhibiting antibiotics occur in the presence of a parallel input of microbial activity stimulating manure. Natural hot spots with already increased soil microbial activity are located in the rhizosphere, comprising microorganism such as Pseudomonas with plant growth promoting and pathogenic strains. The hypothesis was therefore that the antibiotic activity of sulfonamides is promoted in the rhizosphere even in the absence of manure, followed by shifts of the natural plant‐specific microbial community structure. This was evaluated by a laboratory experiment with Salix fragilis L. and Zea mays L. After 40 d of incubation, sub‐areas such as non‐rhizosphere soil, rhizosphere soil and plant roots were sampled. Effects on microbial community structure were analyzed using 16S rRNA gene fragment patterns of total bacteria community and Pseudomonas. Selected exoenzymes of N‐, P‐, and C‐cycling were used to test effects on microbial functions. Compared to the factors soil sub‐area and sulfadiazine (SDZ) content, plant species had the largest influence on the bacterial community structure and soil exoenzyme activity pattern. This was also reflected by an up to 1.5‐fold higher acid phosphatase activity in samples from maize‐ compared to willow‐planted soil. We conclude that antibiotic effects on the bacterial community structures are influenced by the antibiotic concentration and root influence.

Anti-thyroid and antifungal activities, BSA interaction and acid phosphatase inhibition of methimazole copper(II) complexes

It has been reported that various metal coordination compounds have improved some biological properties. A high activity of acid phosphatase (AcP) is associated to several diseases (osteoporosis, Alzheimer’s, prostate cancer, among others) and makes it a target for the development of new potential inhibitors. Anti-thyroid agents have disadvantageous side effects and the scarcity of medicines in this area motivated many researchers to synthesize new ones. Several copper(II) complexes have shown antifungal activities. In this work we presented for a first time the inhibition of AcP and the anti-thyroid activity produced by methimazole–Cu(II) complexes. Cu–Met ([Cu(MeimzH)2(H2O)2](NO3)2·H2O) produces a weak inhibition action while Cu–Met–phen ([Cu(MeimzH)2(phen)(H2O)2]Cl2) shows a strong inhibition effect (IC50=300μM) being more effective than the reported behavior of vanadium complexes. Cu–Met–phen also presented a fairly good anti-thyroid activity with a formation constant value, Kc=1.02×1010M−1 being 106 times more active than methimazole (Kc=4.16×104M−1) in opposition to Cu–Met which presented activity (Kc=9.54×103M−1) but in a lesser extent than that of the free ligand. None of the complexes show antifungal activity except Cu–phen (MIC=11.71μgmL−1 on Candidaalbicans) which was tested for comparison. Besides, albumin interaction experiments denoted high affinity toward the complexes and the calculated binding constants indicate reversible binding to the protein.

Use of biochemical markers to evaluate the quality of fresh and cryopreserved semen from the arctic fox (Vulpes lagopus).

The aim of this study was to use biochemical markers to evaluate the quality of fresh and cryopreserved semen from the arctic fox (Vulpes lagopus). Twenty-three manually collected ejaculates were analysed for the main indicators of semen quality (sperm concentration and ejaculate volume). Sperm motility and percentage of morphologically normal and abnormal spermatozoa were determined according to the stage of cryopreservation (fresh--measurement A; equilibrated--measurement B; frozen/thawed--measurement C). Furthermore, the seminal plasma and supernatants were analysed after equilibration and freeze/thawing for the activity of the enzymes alkaline phosphatase (ALP), acid phosphatase (AcP), lactate dehydrogenase (LDH) and aspartate aminotransferase (AspAT), and for the activity of acrosin inhibitors (AP). The mean concentration of sperm was 625.1 million/cm3, and ejaculate volume averaged 1.6 cm3. Seminal plasma was characterized by the highest activity of alkaline phosphatase (3.43 x 10(3) U/l) and lowest activity of acrosin inhibitors (4.55 x 10(3) U/l). After equilibration, the supernatants showed the highest activity of acid phosphatase (94.9 U/l) and after freeze-thawing, they showed a high activity of lactate dehydrogenase (535.8 U/l) and aspartate aminotransferase (577.1 U/l), which indicates that these proteins had leaked from spermatozoa into the extracellular medium during the biotechnique of semen cryopreservation. In addition, several significant relationships were found between some indicators of semen quality and plasma and/or supernatant enzyme activity.

Cloning of PaAtg8 and roles of autophagy in adaptation to starvation with respect to the fat body and midgut of the Americana cockroach, Periplaneta americana

Starvation, in particular amino acid deprivation, induces autophagy in trophocytes (adipocytes), the major component of the fat body cell types, in the larvae of Drosophila melanogaster. However, the fat body of cockroach has two additional cell types: urocytes depositing uric acid in urate vacuoles as a nitrogen resource and mycetocytes harboring an endosymbiont, Blattabacterium cuenoti, which can synthesize amino acids from the metabolites of the stored uric acid. These cells might complement the roles of autophagy in recycling amino acids in the fat body or other organs of cockroaches under starvation. We investigate the presence of autophagy in tissues such as the fat body and midgut of the American cockroach, Periplaneta americana, under starvation by immunoblotting with antibody against Atg8, a ubiquitin-like protein required for the formation of autophagosomes and by electron microscopy. Corresponding changes in acid phosphatase activity were also investigated as representing lysosome activity. Starvation increased the level of an autophagic marker, Atg8-II, in both the tissues, extensively stimulating the formation of autophagic compartments in trophocytes of the fat body and columnar cells of the midgut for over 2 weeks. Acid phosphatase showed no significant increase in the fat body of the starved cockroaches but was higher in the midgut of the continuously fed animals. Thus, a distinct autophagic mechanism operates in these tissues under starvation of 2 weeks and longer. The late induction of autophagy implies exhaustion of the stored uric acid in the fat body. High activity of acid phosphatase in the midgut of the fed cockroaches might represent enhanced assimilation and not an autophagy-related function.

Hyphosphere interactions between an arbuscular mycorrhizal fungus and a phosphate solubilizing bacterium promote phytate mineralization in soil

Both arbuscular mycorrhizal (AM) fungi and phosphate solubilizing bacteria (PSB) are involved in phosphorus (P) mobilization and turnover but the influence of their interaction on organic P mineralization in the root free soil (hyphosphere) have been little studied. We investigated the interactive effects of an AM fungus (Rhizophagus irregularis, RI) and/or PSB (Pseudomonas alcaligenes, PA) on phytate mineralization and subsequent transfer to the host plant (Medicago sativa) using a two-compartment microcosm with a central 30 μm nylon mesh barrier. The root growth compartment containing 5 mg inorganic P (Pi, KH2PO4) kg−1 soil was inoculated with RI or uninoculated and the AM fungal hyphal soil containing 75 mg organic P (Po, Na-phytate) plus 0 or 5 mg Pi kg−1 soil was inoculated with PA or uninoculated. Sole inoculation with RI increased shoot P content compared with the uninoculated treatment and dual inoculation with both RI and PA did not increase shoot P compared with sole RI inoculation. Sole PA inoculation significantly increased microbial biomass P (MBP). Compared with sole PA inoculation soil MBP increased under zero-Pi addition but decreased under 5 mg Pi kg−1 soil addition in the dual inoculation RI/PA treatment. The uninoculated microcosms had the lowest acid phosphatase activity and the highest phytate-P remaining in the soil. Inoculation with PA led to higher acid phosphatase activity and lower phytate-P than did RI. Dual RI/PA inoculation had the highest acid phosphatase activity and the lowest phytate-P remaining in the soil. Addition of 5 mg Pi kg−1 soil to the hyphal compartment decreased phytate-P remaining in the RI and/or PA treatments. The phytate-P remaining in the soil was negatively correlated with soil acid phosphatase activity or MBP in the presence of RI but there was no correlation between shoot P and soil phytate-P. In conclusion, our results indicate that the mineralization of soil phytate was promoted by the interaction between the AM fungus and its hyphosphere PSB.

METABOLIC CHANGE, TILLERING AND ROOT SYSTEM OF BRACHIARIA BRIZANTHA IN RESPONSE TO PHOSPHORUS AND ZINC NUTRITION

Phosphorus (P) and zinc (Zn) availabilities are important to the nutrition of tropical forage grasses. In this manner, this study aimed to identify and quantify changes in metabolism, tillering, and root system of Brachiaria brizantha cv. ‘Marandu’ related to P and Zn availabilities. Plants of B. brizantha cv. ‘Marandu’ were grown in nutrient solution under five rates of P (0.1, 0.6, 1.1, 1.6, and 2.1 mmol L−1) and five rates of Zn (0.00, 0.75, 1.5, 2.25, and 3.00 μmol L−1), in a fractionated factorial. The interaction P x Zn rates and the Zn supply were not significant for the activity of acid phosphatase enzyme, P-use index, number of tillers, and root parameters. P-use index and enzyme activity decreased as P availability increased. The high efficiency in P use was a result of high acid phosphatase activity and P supply was essential to the development of ‘Marandu’ palisadegrass root system.

Cold-stress induced formation of calcium and phosphorous rich chloragocyte granules (chloragosomes) in the earthworm Eisenia fetida

The cytochemical and functional characteristics of chloragocytes of both ‘control’ and cold-stressed Eisenia fetida were examined. Flow cytometry revealed the heterogeneity of chloragocytes: the first group was characterized by low, the second one by high acid phosphatase (AcP) content. In ‘control’ animals the former, in cold-stressed ones the latter type were the dominant form. The elevated AcP-activity correlated with the accumulation of autophagic vacuoles (AVs) in chloragocytes. Both AVs and all small chloragosomes showed high AcP activity, while most of the large chloragosomes did not display any. Most ‘control’ granules (0.75–1.25μm) contained high amounts of Ca and P, with less and variable quantities of S, Cl, K, Fe and Zn. Small chloragosomes with low Ca and P concentrations were seldom found. In cold-stressed animals the number of small granules (0.25–0.75μm) increased up to 40% of total population. Their Ca and P contents were significantly lower; S and Fe concentrations were higher than those of large chloragosomes (1.0–1.5μm). Our results prove that the formation and elemental composition of chloragosomes can be influenced by environmental stressors and suggest that the mature chloragosomes are tertiary lysosomes and their formation is coupled to autophagocytosis.

Symbiotic responses to insoluble phosphorus supply in common bean (Phaseolus vulgaris L.): Rhizobia symbiosis

The common bean ( Phaseolus vulgaris L .) is often grown under various environmental constraints in soil as well as phosphorus (P) deficiency. In worldwide soils, P massively exists in insoluble forms especially in acidic and basic soils, where it is greatly combined with Al, Fe and Ca ions hydroxide. In order to study the effect of insoluble phosphorus (IP) in hydroponic culture, two common bean varieties, that is, WAFA and REBIA were inoculated separately with three rhizobia strains (P.Tb.09, CIAT899 and P.OM.09) and were grown under mineral P (250 imol P (KH2PO4)) versus IP (250 imol P (Ca2HPO4)). Results show that inoculation of both varieties under 250 imol P with P.Tb.09 and CIAT899 had produced a high nodule biomass of about 0.11 g plant-1. However, inoculation of WAFA with P.Tb.09 and P.OM.09 yielded in a low nodule biomass (0.06 g plant-1) in comparison with REBIA variety showing no variation of the strains used. The last variety in symbiosis with all the three strains, exhibited a high shoot biomass that was not significantly different with plants supplied with 250 imol P. By contrast, a high acid phosphatase activity was more stimulated under IP conditions in leaves of WAFA inoculated with CIAT899 and P.Tb.09. Likewise, root acid phosphatase (APase) activity has increased in REBIA inoculated with P.Tb.09 for both P forms; meanwhile, inoculation with CIAT899 under IP has significantly increased roots acid phosphate (AP) activity. However, this stimulation was not associated with high plant N accumulation that was highly accumulated by both varieties inoculated with P.Tb.09 but grown under 250 imol P. In addition, analysis of phenols content in roots showed a high stimulation when plants had received IP than those under 250 imol P, but to the high extent in roots of REBIA inoculated with P.Tb.09 under IP conditions. We concluded that the use of P-efficient symbiotic combinations against P deficiency seems to be an interesting biological approach to increase legumes P assimilation for N2 fixation and thus for agricultural sustainability. Key words : Symbiosis, Phaseolus vulgaris, rhizobia, insoluble phosphorus, phosphatase, phenolics content.

Toxicological and biochemical effects of some insecticides on peach fly, Bactrocera zonata (Diptera: Tephritidae)

The peach fruit fly, Bactrocera zonata (Saunders, Diptera: Tephritidae), has been a serious pest in the last decade attacking a wide range of fruits in Egypt. The toxicity of Malathion, Diazinon, Methoxyfenozide and Lufenuron to adult males and females of B. zonata was studied under laboratory conditions. The results showed that Diazinon was the most toxic among the tested compounds followed by Malathion, Lufenuron and Methoxyfenozide. LC<sub>50</sub> values for adult males and females were 0.20 ppm, 0.09 ppm and 0.02 ppm (for males), 0.91 ppm, 0.14 ppm and 0,01 ppm (for females), respectively. The results showed that the level of glutamic oxaloacetic transaminase (GOT) of treated adult males and females in 24 h, 48 h, and 72 h post treatment increased compared to untreated adults. The highest activities of GOT in treated adult males in 24 h, 48 h, and 72 h were 92.11µM, 101.99µM and 112.21µM pyruvate released × 10<sup>3</sup>/min/g FW (fresh weight), respectively, for Methoxyfenozide LC<sub>10</sub>, and in treated adult females after 24 h, 48 h, and 72 h they were 84.24µM, 94.33µM, and 111.12µM pyruvate released × 10<sup>3</sup>/min/g FW, respectively, for Diazinon LC<sub>25</sub>. The activities of acetylcholine esterase of treated adults decreased compared to untreated adults. The highest activities of acid phosphatase in adult males after 24 h and 48 h were 249.43 µg and 270.52 µg AchI hydrolysed/min/g FW, respectively, for Methoxyfenozide LC<sub>25</sub>. The highest activities of alkaline phosphatase in adult males were 139.04 µg, 175.67 µg, and 199.29 µg phenol × 10<sup>3</sup>/min/g FW for Malathion LC<sub>10</sub> and in adult females they were 123.31 µg, 162.10 µg and 199.59 µg phenol.10<sup>3</sup>/min/g FW, respectively, for Lufenuron LC<sub>25</sub> in 24 h, 48 h, and 72 h post treatment.

THE EFFECT OF MYCORRHIZA GROWTH AND EXPRESSION OF SOME GENES IN BARLEY

Barley is one of the most important crops for food consumption. Soil fertilization using minerals and chemical compounds are not safe for human health beside beingas expensive. Therefore, It is important to find suitable alternatives. The arbuscular mycorrhiza (AM) is characterized by the formation of arbuscules (sometimes vesicles). The fungus occupies various proportions of the volume of host cells but is separated from the cell cytoplasm by the elaboration of the host plasma membrane forming a fungal membrane and an apoplectic compartment between the fungus and host cytoplasm. Mycorrhiza changes whatever source of phosphorus into phosphoric acid which acidifies the rhizosphere and thus increases the availability of elements for plants uptake. The increase of the availability of elements specially, calcium which plays the main role in cell signaling which could lead to switch on or accelerate the function of several genes such as protein kinases and other genes related with photosynthesis and eventially, affect the plant growth. Inoculation with mycorrhiza increased all plant growth variables such as number of leaves, stem fresh and dry weights and root dry weight Shockley et al. (2004). Gahoonia and Nielsen (2004) reported that the inoculation with mycorrhiza enhanced the release of organic acids and higher acid phosphatase activity in the rhizosphere which may be useful for increasing phosphorus acquisition from inorganic and organic phosphorus pools to the plant. Al-Karaki et al. (2004) found that biomass and grain yields were higher in mycorrhizal than non-mycorrhizal plants. Wu et al. (2005) reported biofertilizer as an alternative to chemical one to increase soil fertility and crop production. Glassop et al. (2005) reported that a very large number of plant species are capable of forming symbiotic associations with arbuscular mycorrhizal (AM) fungi. Moreover, they reported that a large number of phosphate (P) transporters have been identified in plants; tissue expression patterns and kinetic information supports the roles of some of these in the direct root uptake pathways. Chen et al. (2007) indicated that the beneficial impacts of mycorrhizal colonization on plant growth could be largely explained by improved P nutrition. On the other hand, Baltruschat et al. (2008) found that the root endophytic basidiomycete Piriformospora indica increase the tolerance against abiotic stress as in many plants. Gryndler et al. (2009) concluded that mycelia of AM fungi are influenced by organic matter decomposition via release of the compounds during the decomposition process and also by secondary metabolites produced by microorganisms involved in organic matter decomposition. Araim et al. (2009) reported that AM colonization significantly increased the mass of shoots and roots and the concentrations of proteins and most of the phenolics in the roots. Hence, the selected trait of mycorrhiza could play an important role in optimizing the growth of E. purpurea by inducing the production of secondary phytomedicinal metabolites. The impact of mycorrhizaon gene expression has been addressed by some recent studies, Hause et al. (2002) reported that colonization of barley (Hordeum vulgare Cv. Salome) roots by an arbuscular mycorrhizal fungus, led to elevated levels of endogenous jasmonic acid (JA) and its amino acid conjugate JA-isoleucine, whereas the level of the JA precursor remained constant. The rise in jasmonate was accompanied by the expression of genes coding for an enzyme of JA biosynthesis. Delp et al. (2003) performed relative quantitative RT-PCR and western blotting to investigate the expression of three genes with potentially regulatory functions from the arbuscular mycorrhizal fungus Glomus intraradices in symbiosis with barley. Weidmann et al. (2004) identified 29 plant genes which were upregulated in response to Medicago truncatula root inoculation with mycorrhiza. Twenty-two protein spots, 14 upregulated and 8 downregulated were found changed in mycorrhiza inoculated plants as compared with the non inoculated ones by Liang et al. (2007). Abo Doma et al. (2008) indicated that the treatment with mycorrhiza significantly increased plant growth in two cultivars of wheat using different yield related traits. Moreover, transcriptome analysis using real timereverse transcriptase indicated that mycorrhiza treatment resulted in an increase in the gene expression of proline 5 carboxilate synthetase (P5CS) on the transcription level. Roldan et al. (2008) indicated that differential gene expression for genes conferring superoxide dismutase and peroxidases were recorded between mycorrhizal and non-mycorrhizal shoots of juniperus oxycedrus seedling. This investigation aimed to: 1- study the effect of barley root inoculation with mycorrhiza on some plant traits and 2-determine the changes in gene expression of the genes conferring calcium dependent protein kinases (CDPKs), phosphoenol pyrovate carboxylases (PEPCs) and proline-5 carboxylate synthetase (P-5CS) in barley plants in response to their inoculation with mycorrhiza at the molecular level as quantified using RT-PCR.

The Ecology of Podocarps in Tropical Montane Forests of Borneo: Distribution, Population Dynamics, and Soil Nutrient Acquisition

We review the ecology of podocarps on various soil types in Borneo, largely relying on our studies conducted on Mount Kinabalu. Podocarps are generally abundant in montane forests, but their abundance varies with soil nutrient status, and they can occur in lowland forests where soil nutrients are scarce. These patterns suggest control by soil nutrients rather than by temperature. Analyses of population structure, growth rate, and crown light conditions in montane forests indicate that podocarps are generally shade intolerant and require canopy gaps or sparse canopy for regeneration. Podocarps have greater maximum tree sizes than most co-occurring angiosperm species in Mount Kinabalu forests. Once they reach the upper canopy layer, they persist for a long time because of their long life span, allowing them to regenerate in rare events of canopy disturbance. The roots of two podocarp species (Dacrycarpus imbricatus and Dacrydium gracile) showed a greater acid phosphatase activity when compared with angiosperm roots within the same lower montane forest. Moreover, an analysis using lipid biomarkers indicated that saprophytic fungi are more abundant in the soils beneath the two podocarps than beneath angiosperms, and a fungal biomarker lipid correlated with soil acid phosphatase activity. The dominance of saprophytic fungi appears to be related to high soil acid phosphatase activity, suggesting feedback effects between the podocarps and soil microbial communities. These results indicate that podocarps are efficient in the acquisition of phosphorus from the acidic montane soils and decomposing litter. We suggest that the architectural and life history advantages and physiological adaptations to nutrient limitation are essential for the persistence of podocarps, despite their lower shade tolerance as compared to angiosperms.

Enhancement of acid phosphatase secretion and Pi acquisition inSuaeda fruticosaon calcareous soil by high saline level

The aim of this study was to identify the relationship between the adaptive processes of Suaeda fruticosa for Pi acquisition and the physic-chemical and biological characteristics of two soil types under moderate and high saline conditions. Four treatments were established in pots: namely SS100, SS600, CS100 and CS600 where SS stood for sandy soil and CS for calcareous soil, and the indexes 100 and 600 were NaCl concentrations (mM) in irrigation distilled water. Assuming that Pi per g of plant biomass is an indicator of plant efficiency for P acquisition, the results showed that Pi acquisition was easiest on SS100 and was difficult on CS100. The differences in Pi acquisition between plants on SS100 and CS100 could be attributed to the low root surface area (-30%) and to the low alkaline phosphatases (Pases) activities (-50%) in calcareous rhizospheric soil. The high salinity level had no effect on the efficiency of P acquisition on SS but increased this parameter on CS (+50%). In the latter soil type, high acid phosphatase activities were observed in rhizospheric soil at high salinity level. Acid phosphatase seemed to be secreted from the roots. The higher secretion of acid phosphatase in this soil was related to the root lipid peroxidation in response to elevated salinity associated with the augmentation of unsaturated acids which might induce an oxidative damage of the root membrane. Thus we can conclude that in deficient soil such as calcareous, the efficiency of P acquisition in S. fruticosa which was difficult at moderate salinity level can be enhanced by high salinity level.

The activity of macrophage aggregates in the liver of flounder ( Platichthys flesus) and wrasse ( Symphodus melops) is associated with tissue damage

The phagocytic activity of macrophage aggregates (MAs) in the liver of fish is characterized by high acid phosphatase activity and generation of reactive oxygen species (ROS). Question of the present study was whether these activities were associated with damage of adjacent and surrounding liver cells and the macrophages itself. Thus, the lysosomal membrane stabilities (LMS) of two different populations of lysosomes (LMS1, short destabilization periods, and LMS2, longer destabilization periods) of liver cells close to MAs of different phagocytic activity were measured as indicator for cellular integrity by computer assisted image analysis. They were then compared to the LMS of hepatocytes remote from any MA. In addition, LMS was also assessed inside the MAs. Studies were performed on adult European flounder ( Platichthys flesus) and corkwing wrasse ( Symphodus melops) caught at clean and polyaromatic hydrocarbon (PAH)-contaminated field locations of the German Bight and the Karmoy peninsula at the West coast of Norway. In the hepatocytes adjacent to MAs which showed medium to high phagocytic activity, LMS was significantly decreased with a reduction of both, first (LMS1), and second (LMS2) destabilization periods in both species. LMS1 inside of these MAs was extremely low, whereas LMS2 was sometimes even higher compared to the liver cells. We suggest that LMS1 represents phagosomes which had contact to ROS and LMS2 represents less affected primary lysosomes. In single flounder and wrasse with liver tumors, MAs in the vicinity of these tumors showed low phagocytic activity and were not associated with adverse effects on adjacent tumor cells. Inside these MAs, LMS1 was higher compared to MAs with high phagocytic activity in wrasse from the reference site, indicating that cytotoxicity was not involved in their phagocytic deficiency.