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PubMed2005

Activity profiling of ectomycorrhiza communities in two forest soils using multiple enzymatic tests.

Data on the diversity and distribution of enzyme activities in native ectomycorrhizal (ECM) communities are inadequate. A microplate multiple enzymatic test was developed which makes it possible to measure eight enzyme activities on 14 individual, excised ECM root tips. Hydrolytic and oxidative enzymes are involved in the decomposition of lignocellulose, chitin and phosphorus-containing organic compounds. This test system was used to describe the functional diversity of ECM communities in two forest sites. This set of tests proved to be accurate and sensitive enough to reveal a high diversity of activity profiles, depending on the fungal symbiont and the soil horizon. Ectomycorrhizas can be classified into specialists and generalists, and appear to complement each other in the same horizon to collectively perform all eight activities studied. By including a higher number of different assays for more detailed analyses, ECM activity profiling will provide a valuable tool for studying the functional diversity of ECM communities.

Biodiversity↗
PubMed1987

Brain intracellular pH and metabolism during hypercapnia and hypocapnia in the new-born lamb.

1. The effects of hypercapnia and hypocapnia on brain intracellular pH (pHi) and metabolism were investigated in new-born lambs under barbiturate anaesthesia. 2. 31P nuclear magnetic resonance (n.m.r.) spectroscopy was used to determine brain pHi and the relative concentrations of compounds containing mobile phosphorus nuclei including phosphocreatine (PCr), nucleoside triphosphates (NTP) and inorganic phosphate (Pi). Simultaneous measurements were made of the molar ratio of glucose to oxygen uptake by the brain. 3. During normocapnia (arterial partial pressure of CO2 Pa, CO2, 39 +/- 1 mmHg mean +/- S.E. of mean, n = 9) brain pHi was 7.13 +/- 0.02. Hypercapnia (Pa, CO2, 98 +/- 3 mmHg) was associated with a fall in brain pHi to 6.94 +/- 0.03 (n = 19, P less than 0.001), whereas no significant change in brain pHi occurred during hypocapnia (Pa, CO2, 16 +/- 1 mmHg; brain pHi 7.15 +/- 0.01). 4. During hypercapnia there was an increase in the ratio of Pi to NTP from 1.09 +/- 0.08 to 1.47 +/- 0.06 (P less than 0.001) and a decrease in the ratio PCr/Pi from 1.60 +/- 0.08 to 0.93 +/- 0.04 (P less than 0.001). There was a linear correlation between Pi/NTP and brain pHi. 5. Alterations in arterial PCO2 had no significant effect on the molar ratio of glucose to oxygen uptake by the brain, which remained close to unity. 6. The change in brain pHi observed during hypercapnia can be accounted for by the known physico-chemical buffering capacity of brain tissue. Homoeostasis of brain pHi during hypocapnia provides further evidence that additional regulatory mechanisms operate in these circumstances. 7. The observed changes in PCr and Pi can be accounted for in part by the [H+] dependence of the creatine kinase reaction.

Animals↗
PubMed1995

Organophosphonate Utilization by the Wild-Type Strain of Penicillium notatum.

We studied the biodegradation of compounds containing phosphorus-to-carbon bonds by using a wild-type strain of Penicillium notatum. The substrate specificity of this strain was studied, and we found that it is able to utilize structurally diverse organophosphonates as sole sources of phosphorus. This ability seems to be inducible, as indicated by the presence of a lag phase during growth. A popular herbicide, glyphosate, inhibited fungal growth, but it was also degraded by the fungus if it was applied in sublethal doses. This indicates that P. notatum may play an important role in biodegradation of organophosphonates. The strain which we used did not metabolize any of the phosphonates which we tested when they were used as sole carbon or nitrogen sources.

Journal Article↗
PubMed1986

Reductive activation of diaziquone and possible involvement of free radicals and the hydroquinone dianion.

To analyze the mode of action of diaziquone [AZQ] on DNA, we examined the activity of two AZQ analogues and N,N',N"-triethylenethiophosphoramide on three forms [supercoiled (Form I), open circular (Form II), and linear (Form III)] of PM-2 DNA. The AZQ analogues contained chlorine atoms which substituted either the carbethoxyamino groups or the aziridine groups of the parent compound. N,N',N"-triethylenethiophosphoramide is a triaziridine compound containing pentavalent phosphorus instead of a quinone group. We found that only when reduced with sodium borohydride did AZQ change the topology of the three forms of PM-2 DNA by introducing mainly single strand breaks. The AZQ analogue containing only aziridines (RQ2) was active in both its oxidized and its reduced forms, while the analogue containing only the carbethoxyamino groups (RQ14) or N,N',N"-triethylenethiophosphoramide were not active in either form. Under similar experimental conditions, Adriamycin alone altered the electrophoretic mobility of PM-2 DNA, while borohydride reduced Adriamycin did not. By using electron spin resonance spectroscopy, we showed that dihydrodiaziquone (AZQH2) oxidizes to the semiquinone in the presence of oxygen. Although AZQH2 was active against DNA, it was not active against cellular DNA synthesis as measured by [3H]thymidine incorporation into exponentially growing HEp-2 cells. However, AZQ alone prevented [3H]thymidine incorporation into HEp-2 cells. We found that HEp-2 cells have the ability to reduce AZQ to its free radical anion, but AZQH2 does not autoxidize to the free radical in the presence of cells. The reductive ability of HEp-2 cells may be responsible in part for preventing the oxidation of AZQH2 to the free radical. We found that under our conditions (1-h incubations) the aziridines are essential for the activity of aziridinyl quinones against PM-2 DNA and that in the case of AZQ the hydroquinone is also required.

Aziridines↗
PubMed2001

Stability of phosphorus within a wetland soil following ferric chloride treatment to control eutrophication.

Addition of iron and aluminum compounds has become an increasingly popular method to regulate phosphorus eutrophication in lakes and reservoirs. It has been proposed that ferric chloride addition to agricultural runoff entering the northern Everglades could provide a means for enhancing natural mechanisms of phosphorus removal from the wetland. In this study we added ferric chloride to Everglades water spiked with 32PO4, incubating the resulting precipitates in microcosms simulating the Everglades ecosystem. 32P activity and reduction-oxidation (redox) potentials were monitored to determine if the 32P was released into the overlying water column due to iron reduction. Results of redox potential measurements and 32P activity indicate that although reducing conditions exist in the soil, on average less than 1% of the added 32P was measured in the water column during the 139-day incubation. Ferric chloride addition thus might prove an effective means of long-term phosphorus retention in the Florida Everglades and perhaps other wetland systems.

Agriculture↗
PubMed1979

The potential of some synthetic pyrethroids for control of the cattle tick (Boophilus microplus).

As part of a continuing programme to aid in the development of new acaricides, the potentials of three synthetic pyrethroids, permethrin, cypermethrin and decamethrin, were assessed against a range of resistant strains of the cattle tick (Boophilus microplus). The compounds were shown to be acaricidal, with decamethrin the most effective, giving efficient control of susceptible and organo-phosphorus resistant strains of the cattle tick at concentrations as low as one fifth of those previously used for any commercial acaricide. However higher concentrations were required for satisfactory control of the DDT-resistant strain. Permethrin-selection of a field strain containing a low percentage of DDT-resistant ticks led to rapid development of resistance to a level equivalent to that of the DDT-resistant strain. Further selection increased resistance to permethrin to a higher level than that shown in the DDT-resistant strain. This increased resistance to permethrin appears to be restricted mainly to this compound and is not associated with a marked increase in resistance to cypermethrin, decamethrin or DDT. The potential of organo-phosphorus compounds to potentiate the pyrethroids when the two classes of compounds are used as mixtures against the pyrethroid-resistant and susceptible strains was confirmed.

Animals↗
PubMedDate not supplied

Determination of acidic herbicides and related compounds in water and soil by capillary gas chromatography using a nitrogen-phosphorus detector.

Methods are described for the determination of acidic herbicides and related compounds in water and soil. Eight acidic herbicides and related compounds were extracted from water using either dichloromethane or an XAD-2 resin column. The acidic moieties were derivatized with 2-cyanoethyldimethyl(diethyl)aminosilane. The derivatized compounds were separated using capillary gas chromatography and quantitated using a nitrogen-phosphorus detector. Extraction from water using dichloromethane or an XAD-2 resin column resulted in recoveries greater than 90% at 0.1 ppb with an average coefficient of variation (CV) of 6%. In soils extracted with aqueous acetonitrile-acetic acid and partitioned into dichloromethane, recoveries at 500 ppb were greater than 75% with an average CV of 3.3%. The methods are rapid and there are few interferences.

Chemical Phenomena↗
PubMedDate not supplied

[Effect of carbostimulin on reparative osteogenesis in rabbits of different ages].

Rate of reparative osteogenesis was studied after partial resection of rabbit radius bone. Within 15 days of the restoration period the content of dry residue was increased by 26%, 17% and 35% in regenerate of 2-months old animals, treated with their mixtures as compared with 6-months old rabbits. Content of calcium was increased 1.5-fold in callus of all the 2-months old animals as compared with that in the 6-months old rabbits.

Animals↗
PubMed1996

Isolation and composition of inositolphosphorylceramide-type sphingolipids of hyphal forms of Candida albicans.

Hyphal forms of the human pathogen Candida albicans have been found to contain substantial quantities of phosphosphingolipids. These lipids were fractionated into three classes by normal-phase high-performance liquid chromatography. The first class contained equimolar amounts of phosphorus, inositol, phytosphingosines, and fatty acids; their composition and chromatographic behavior suggest that these compounds are inositolphosphorylceramides. The second class contained equimolar amounts of phosphorus, mannosylinositol, phytosphingosines, and fatty acids; their composition and chromatographic behavior indicate that these compounds are mannosylinositolphosphorylceramides. The third class of compounds contained phosphorus, mannosylinositol, inositol, phytosphingosines, and fatty acids in a molar ratio of 2:1:1:1:1; their composition and chromatographic behavior indicate that these compounds are mannosyldiinositolphosphorylceramides. Molecular species in each class differ in the composition of long chain bases and fatty acids; the most abundant long chain bases were C18 and C20 phytosphingosines, and the most abundant fatty acids were hydroxy and nonhydroxy C24-26. The array of sphingolipids in C. albicans is similar to that of Saccharomyces cerevisiae. Sphingolipids have been shown to be essential in S. cerevisiae, thus these lipids, which are not present in animals, offer a potentially unique target for antifungal chemotherapy against C. albicans.

Alkalies↗
PubMed1995

1 alpha-Hydroxylated cholecalciferol compounds act additively with microbial phytase to improve phosphorus, zinc and manganese utilization in chicks fed soy-based diets.

Seven experiments were conducted to determine the efficacy of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] and microbial phytase in improving P, Zn and Mn utilization of chicks fed P, Zn- and Mn-deficient soy protein diets containing surfeit levels of cholecalciferol. Efficacy of 1 alpha-hydroxycholecalciferol (1 alpha-OH D3) was also studied. A dose titration study indicated that supplemental phytase at 1200 units/kg diet would increase bone ash by at least 65% when added to a corn-soybean meal diet containing 0.43 g P/100 g (0.1 g nonphytate P/100 g). These responses were similar to those obtained from supplemental P (0.1 g/100 g) as KH2PO4 or from added 1,25-(OH)2D3 (10 micrograms/kg). Dietary addition of both 1200 units phytase and 10 micrograms/kg 1,25-(OH)2D3 elicited bone ash responses that were near 100%. When chicks were fed a Zn-deficient soy-concentrate diet (13 mg Zn/kg), diet supplementation with 1,25-(OH)2D3 or phytase increased growth rate by 40% and tibia Zn content by > 100%; adding 1,25-(OH)2D3 together with phytase increased tibia Zn content by 160%. Utilization of both Zn and Mn contained in the corn-soybean meal diet also was markedly enhanced by supplemental phytase, 1,25-(OH)2D3, or the combination. The cholecalciferol analog 1 alpha-OH D3 was found to improve dietary P utilization maximally (70% bone ash response) at a dose of 20 micrograms/kg diet, and effects were additive when 1 alpha-OH D3 was fed in the presence of phytase.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Phytase↗
PubMed2005

[Infrared spectra of polyoxometalates].

The infrared spectra of polyoxometalates are addressed. The vibration frequencies of some synthesized polyoxometalates in recent years are emphasized. It was found that the infrared spectra of polyoxometalates result from stretch vibration frequency of the metal-oxygen, and 1 100-400 cm(-1) is the region of the characteristic absorption peak. The infrared spectrum contains information about the symmetry of polyoxoanion as well. As an analytical means, the infrared spectrum can be used to distinguish heteropolyanion and provide information on structure.

Models, Chemical↗
PubMed2001

Phosphorus retention capacity of iron-ore and blast furnace slag in subsurface flow constructed wetlands.

The suitability of iron-ore and blast furnace slag for subsurface flow (SSF) constructed wetlands was studied over a period of four months. Dairy farm wastewater (TP 45 mg l(-1)) was percolated through buckets planted with reed (volume 9.1 l; hydraulic load 151 m(-2) d(-1)). One group of buckets was kept under aerobic conditions and the other group under anaerobic conditions, monitored by continuous redox potential measurements. Even at high mass loading rates of 0.65 g P m(-1) d(-1) the slag provided 98% removal efficiency and showed no decrease in performance with time. However, phosphorus fractionation data indicate that the high phosphorus retention capacity under aerobic conditions is to a great extent attributable to unstable sorption onto calcium compounds (NH4Cl-P). Phosphorus sorption of both the slag (200 microg P g(-1)) and the iron-ore (140 microg P g(-1)) was promoted by predominantly anaerobic conditions due to continuous formation of amorphous ferrous hydroxides. None of the substrates had adverse affects on reed growth.

Adsorption↗