Extraction Of Sm Research Articles

Differences in DNA sequence recognition by the heat-shock factors of Drosophila melanogaster and the parasitic helminth Schistosoma mansoni

It was recently shown that schistosome extracts contain heat-shock factor (HSF) activity that correlates with the pattern of hsp70 mRNA levels at different developmental stages of the parasite (Levy-Holtzman and Schechter (1994) Parasitology 108, 35–42). To extend our understanding of the HSF activity revealed in extracts of Schistosoma mansoni (Sm), it was further analyzed by competition experiments and compared with the well characterized HSF of Drosophila melanogaster (Dm). The interactions of HSF in Sm extracts (SmHSF) and HSF of Dm (DmHSF) with 32P-labeled heat shock element (HSE) probes, with and without unlabeled competitor DNA probes (HSE-related oligos), were analyzed by gel retardation assay. The binding and inhibition studies demonstrated that SmHSF and DmHSF differ in HSE sequence recognition: an array of three mGAAn inverted repeats according to the ideal consensus sequence (nGAAnnTTCnnGAAn) is recognized by DmHSF, but not by SmHSF. In the schistosome, binding is attained only when the third pentamer is a variant, composed of nG T An instead of nG A An. The presence of this variant in the promoter of the hsp70 gene of the parasite suggests coevolution of the variant sequence together with the SmHSF which interacts efficiently with the variant, but not with the ideal HSE sequence. Further inhibition studies revealed additional differences between SmHSF and DmHSF in recognition of the first and second nGAAn pentamers of HSE. In analogy to other systems of ligand-protein interactions, we propose that the complementarity between the HSE ligand and the HSF protein is higher in SmHSF, as compared to DmHSF.

Synergistic extraction behavior of samarium(III), europium(III) and dysprosium(III) with 1-nitroso-2-naphthol and 1,10-phenanthroline

The equilibrium extraction behavior of Sm(III), Eu(III) and Dy(III) from aqueous NaClO4 solutions in the pH range of 4–9 at 0.1 M ionic strength into organic solutions of 1-nitroso-2-naphthol (HA) and 1,10-phenanthroline (Phen) has been studied. The equilibrium concentrations of Eu were assayed through the 344 keV photopeak of the152Eu radiotracer used. The concentrations of Sm and Dy were measured by irradiating one mL portions of the organic extract and analyzing the 104 and 108 keV photopeaks of the short-lived neutron activation products,155Sm and165mDy, respectively. Quantitative extraction of Eu with 5×10−2 M HA alone was obtained in the pH range of 6.7–7.8 with n-butanol, 7.4–8.5 with chloroform, 8.0–8.7 with ethyl acetate, 7.7–8.5 with isoamyl alcohol and 6.1–8.0 with methyl isobutyl ketone (MIBK). But, Eu was extracted only to a maximum of 78% and 83% in the pH range of 8.3–8.9 and 7.4–8.1 with carbon tetrachloride and xylene, respectively. The extraction of Sm and Dy were found quantitative in the pH range of 6.3–7.0 and 6.6–7.1, respectively, with 5×10−2 M HA alone in MIBK solutions. The synergistic extraction of Eu was quantitative in the pH range of 6.6–9.8 with chloroform, 7.8–8.9 with ethyl acetate, 7.7–8.5 with isoamyl alcohol and 6.0–9.6 with MIBK when 1×10−2 M each of HA and Phen were employed. Sm and Dy were quantitatively extracted into MIBK solutions containing 5×10−2 M each of HA and Phen in the pH range 6.0–7.5 and 6.1–7.5, respectively. The distribution ratios of these lanthanides (Ln) were determined as a function of pH, and HA and Phen concentrations. The analysis of the data suggests that these Ln are extracted as LnA3 chelates when HA alone is used. In the presence of HA and Phen, both LnA3(Phen) and LnA3(Phen)2 adducts are formed only in the MIBK system while LnA3(Phen) complexes are the predominant ones in all other solvent systems studied. The extraction constants and the adduct formation constants of these complexes have been calculated.

Pest Control with Proteinase Inhibitors: Is It Compatible with IPM Strategies?

In recent years, several studies have demonstrated the potential of proteinase inhibitors (PIs) for the control of various pests and pathogens. Used as a component of an integrated pest management program, such an approach must, however, be carefully considered, given the possible risks of interference with other control methods. For example, we are analyzing the effect of oryzacystatins (OCI and OCII), two cysteine PIs naturally occurring in rice grains, against digestive proteinases of Amblyseius californicus (AC), a native predator of the two-spotted spider mite (SM; Tetranychus urticae). Electrophoretic analyses have shown the existence in SM extracts of a major cysteine proteinase form strongly inhibited by OCI, indicating the potential of this inhibitor for SM control. However, similar analyses revealed a strong affinity between proteinases from AC extracts and OCs. Thus, despite their potential for SM control, plant cystatins may represent growth-suppressing compounds for AC. Work is currently underway to determine the usefulness of OCI-expressing transgenic plants for SM control, and to assess the compatibility of this control with an AC-based biological control strategy.

希土類磁石材料スクラップのリサイクリングに関する研究

The rare earth magnet has a good performance, and the production is increasing year by year. Two types of rare earth magnets are presently made as industrial products. One is a Nd-Fe-B intermetallic compound magnet and the other is a Sm-Co alloy magnet.Mixed scraps of Nd-Fe-B intermetallic compound and Sm-Co alloy are sometimes produced in the step of production. Therefore, it is desired that the recycling system of mixed rare earth magnet scraps shall be established.In the present study, the extraction and separation of Nd and Sm by solvent extraction is mainly tested to obtain the fundamental data for the hydrometallurgical treatment of the mixed rare earth magnet scraps. The results obtained in this study are summarized as follows:(1) The separation efficiency of Nd and Sm from hydrochloric acid solutions is better than that from sulphuric acid solutions.(2) The extractant combinations, EHPNA/ TOPO and EHPNA/TOA are favourable to the extraction and separation of Nd and Sm, compared with other extractants tested in this study.(3) The hydrometallurgical process of mixed rare earth magnet scraps based on oxidizing roasting, hydrochloric acid leaching, and solvent extraction is proposed.

Synergic Extraction of Rare Earths(III) with 4,4,4-Trifluoro-1-(2-thienyl)-1,3-butanedione and Nitrogen-Involving Polydentate Ligands as Diethylenetriamine and Triethylenetetramine

Abstract The synergic extraction of rare earths(III), i.e. La, Sm, Tb, and Lu, using 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Htta) and a nitrogen-involving neutral polydentate ligand, such as diethylenetriamine (dien) or triethylenetetramine (trien), was studied between benzene and aqueous phases. The synergic enhancement of this extraction system was attributed to the formation of an adduct, RE(tta)3dien or RE(tta)3trien. The adduct formation constants (βS,1) were determined. Although βS,1 decreases with the atomic number of RE(III), the detailed tendency of βS,1 depends on the number of nitrogen atoms of the polydentate ligands.

Mixed ligand complexation in the extraction of Dy(III) and Sm(III) with the HTTA-TBA synergic system

Synergic extraction of hydrolyzable lanthanides Dy(III) and Sm(III) has been studied in the low pH range with 0.3M (HTTA-TBA) in chloroform from aqueous perchlorate media. The synergic coefficient was calculated at different pH's and was found maximum at pH 3 for both elements. The composition of the adduct was established as M(TTA)3.3TBA at pH 3. However, a mixture of the adduct of the type M(TTA)3.TBA was proposed at pH 5.9. The possible reaction mechanism at both pHs is discussed, the stability constant βm,n′ formation constants Km,o and Km,n have been calculated.

Synergic extraction of lanthanide(III) ions with 2-thenoyltrifluoroacetone in the presence of 2,2′-bipyridine or pyridine

The synergic extraction of various tervalent lanthanides (Ln), La, Ce, Nd, Sm, Gd, Tb, Yb and Lu, with 2-thenoyltrifluoroacetone (Htta) in the presence of a bidentate heterocyclic amine, 2,2′-bipyridine (bipy), in benzene was investigated. The synergic enhancement was attributed to the formation of the adducts, Ln(tta)3(bipy). The synergic extraction of La(III), Sm(III) and Lu(III) with Htta and a unidentate amine, pyridine (py), was also studied and the formation of the adducts, Ln(tta)3py and Ln(tta)3(py)2, was observed. The adduct formation constants, βs,1 and βs,2, were determined. The βs,2 values for py decrease with increasing atomic number of Ln(III), but βs,1 values for bipy increase with increasing atomic number of Ln(III). The synergic extraction constants and the separation factors in the bipy system were also determined.

Adduct formation constant in the synergic extraction of several rare earth elements with acetylacetone and 1,10-phenanthroline in nonpolar organic solvents

The synergic extraction of La(III), Nd(III), Sm(III), Tb(III) and Lu(III) with 0.1M acetylacetone (Hacac) and 1,10-phenanthroline (phen) in benzene was studied. The adduct formation constant, βs, for RE(acac)3 (phen) in benzene was determined. The βs decreases with inceasing atomic number of RE(III). The βs in different organic solvents can be predicted in connection with the activity coefficients of the solutes, and the validity of this prediction is confirmed by good agreement with the experimental values of βs in carbon tetrachloride and heptane.

Effect of an acidic chelating agent in the synergic extraction systems of rare earth(III)β-diketones-2,2′-bipyridine

The extraction of rare earth elements (RE), La(m), Sm(III), Tb(III), Tm(III) and Lu(III), with four β-diketoncs (HA), hexafluoroacetylacetone (Hhfa), pivaloyltrifluoroacetone (Hpta), benzoyl- acetone (Hba) and acetylacetone (Hacac), in the presence or absence of 2,2′-bipyridine (bpy) in benzene was studied. The extraction constants ( K ex) for RE(III) with Hhfa, Hpta and Hacac were determined and compared with each other. The order of K ex is Hacac < Hpta < Hhfa. The synergic enhancement observed in the presence of bpy is attributed to the 1:1 adduct formation such as RE(A) 3bpy, except for the La(III)-Hhfa system, in which La- (hfa) 3(bpy) 2 was also observed. The adduct formation constant, β s,1, tor the β-diketones was in the order of Hacac < Hba < Hpta < Hhfa, which is in the same order as their acid dissociation constants. The trend of β s,1 with the atomic number of RE is obviously different with different β-diketones; the β s,1 for Hacac and Hba tends to decrease with increasing atomic numbers of RE, but those for Hpta and Hhfa increase.

A Regularity of the Liquid-Liquid Partition Coefficients of Tris(acetylacetonato) Rare Earth(III) Chelates

The extraction of La(III), Nd(III), Sm(III), Tb(III) and Lu(III) with acetylacetone in benzene has been studied. The partition coefficients of these tris- (acetylacetonato) rare earth(III) chelates do not show the same value but increase as the atomic number of rare earth increases. From comparison of the experimental partition coefficient with the theoretical partition coefficient for the tris-acetylacetonato metal(III) chelate estimated from the regular solution concept and the cavity formation energy, this tendency is ascribed to the gradual decrease of the hydration of the neutral chelate in the aqueous phase.

The Synergistic Extraction of Sm(NO3)3and Gd(NO3)3by a Mixture of Tributyl Phosphate and Aliquat 336 in AMSCO and Ammonium Nitrate Medium

Abstract The synergic extraction of Sm and Gd using a mixture of tri-butyl phosphate and Aliquat 336 is presented. The influence of diluents, salting out agents and acidity on the synergic extractions have been investigated. The separation factor of Sm and Gd was found to be larger than 3. This is one of the best systems for the separation of Sm and Gd. NH4NO3 was found to be extracted by pure TBP or pure Aliquat 336, but cannot be extracted by a mixture of TBP and Aliquat 336.

Influence of partially purified extracts of Solanum malacoxylon on bone resorption in organ culture.

The water-soluble active principle of the plantSolanum malacoxylon (SM) was partially purified by column chromatography, and its bone-resorbing activity was tested by using an organ culture system of 18-day fetal mouse fibulae prelabeled with45Ca. Three series of experiments were performed. In the first series, the aqueous extract of SM was submitted to Sephadex G-25 chromatography to separate the active substances. From six collected fractions only two exhibited reproducible bone-resorbing activity as indicated by an increased release of45Ca from bone rudiments. In the second series, the active fractions were combined and lyophilized to a powder which was dissolved in the culture media to obtain the concentrations of 5, 25, 50, and 100 μg/ml. The addition of this saltfree material resulted in a dose-related accentuation of45Ca release from fetal mouse bones into the medium. Histologically, the treated fibulae showed greater numbers of osteoclasts than the controls and a disappearance of bone trabeculae. In the third series, the active material was further purified on Sephadex LH-20 column. From four collected fractions, only one showed bone-resorbing activity in vitro. It is concluded that the purified active factor of SM exerts a direct effect on bone. It stimulates the mobilization of bone calcium in vitro by increasing the population of osteoclasts. The nature of the active principle remains unknown.

Potentiation of the effects of Solanum malacoxylon extracts on rat intestinal phosphate and calcium absorption by incubation with ruminal fluid.

The effects of a partially purified aqueous extract ofSolanum malacoxylon (SM) leaves and of an SM extract incubated with ruminal fluid (RF) prior to administration on intestinal phosphate and calcium absorption in rachitic rats were compared with 1α, 25-dihydroxy-vitamin D3[1α,25-(OH)2-D3] using a duodenal loop in situ method. The time course responses elicited by both extracts were qualitatively similar to that of 1α, 25-(OH)2-D3. However, a single dose of SMRF was significantly more effective in stimulating32P absorption than an equivalent dose of SM. Part of this difference can be accounted for by incomplete saturation of the phosphate transport system with the level of SM employed. Treatment with rumen potentiated the effects of SM on45Ca absorption to a lesser extent. Extraction of SMRF with nonpolar organic solvents and purification of the lipid extract by chromatography on Silica Gel G thin-layer plates and on Sephadex LH-20 columns yield two fractions which promote intestinal32P absorption. The bioactive fraction eluting first from the Sephadex LH-20 column migrates similarly as 1α,25-(OH)2-D3. The greater effectiveness of SMRF extracts on intestinal phosphate and calcium absorption may be tentatively attributed to the release of 1α,25-(OH)2-D3 from the corresponding glycoside, shown previously to be present in SM, and to steroid modification during incubation with rumen.