ADSORPTION OF LEAD, COPPER, ZINC, COBALT, AND CADMIUM BY SOILS THAT DIFFER IN CATION-EXCHANGE MATERIALS

The adsorption of Zn²⁺, Pb²⁺, Cu²⁺, Co²⁺, and Cd²⁺ (M²⁺) by soils was measured at concentrations ranging from 10-⁷ to 10-² M in 10-³ to 10-² M CaCI₂. Exchange between Ca²⁺ and M²⁺, and solubility products [M²⁺][OH^?]² indicate that M²⁺ is not precipitated as hydroxide but is adsorbed on cation-exchange sites. The proportion of selective adsorption sites with specified values of the selectivity coefficient calculated using Ca as reference ion, increased in the order montmorillonite < humus, kaolinite, < allophane. imogolite < halloysite, iron oxides. Raising the soil pH by Ca-saturation increased both the amount and affinity of adsorption. Selectivity of adsorption increased in the order Mg, Ca < Cd, Co < Zn < Cu, Pb, and the selectivity coefficient varied from < 1 to > 10 000. The formation of the coordination complexes of heavy metal with deprotonoted OH and COOH groups as ligands is suggested as a possible mechanism of selective adsorption.     

Ammonium-calcium exchange equilibria in soils and weathered pumices that differ in cationexchange materials

The retention of NH₄+ and Ca²+ on soil and weathered pumice samples containing constant and/or variable charge components was measured in different NH₄CI-CaCl₂ solutions. The NH₄+/Ca²+ selectivity of each sample was evaluated using a quotient of the partition of NH₄+ on the exchange sites and in the solution relative to that of Ca²+. It increased with decreasing pH and increasing NH₄Cl-CaCl₂ concentration for a given equivalent fraction of NH₄+ in the solution. These effects were quantitatively explained in terms of the changes of NH₄+ and Ca²+ concentrations in the solution and in the diffuse double-layer of the ion-exchange material as predicted by the law of mass action and the electric double layer theory. The NH₄+/Ca²+ selectivity of different exchange materials showed a similar variation among their exchange sites and increased in the order humus, allophane and imogolite (Si/Al ratio 0.5) < allophane (Si/Al ratio 1.0), montmorillonite < vermiculite, illite < halloysite. The origin of negative charge, the steric features around the exchange sites and clay-humus interaction are suggested as being important in determining the NH₄+/Ca²+ selectivity.     

Interlayer materials of partially interlayered vermiculites in Dystrochrepts derived from Tertiary sediments

Interlayer materials of partially interlayered vermiculites (PIV) in 15 Dystrochrepts derived from Tertiary sediments were analysed by dissolution with hot 1/3M sodium citrate or 0.15 M oxalate-oxalic acid in combination with XRD and IR spectroscopy. Both the citrate and oxalate treatments dissolved Al from all soil clays. The dissolution of Al by the citrate treatment paralleled the dissolution of Si and the interlayer collapse of PIV, whereas that by the oxalate treatment did not, indicating that the interlayer materials contain not only Al but Si. The materials dissolved by the citrate treatment had a molar Si/Al ratio ranging from 0.72 to 0.24 that decreased with the increasing interlayering of PIV. Differential IR spectroscopy indicated the dissolution of aluminosilicates possibly having Si-O, Al-OH and Si-O-Al bonds, but not Si-O-Si bonds. The extent of interlayering of PIV showed a good correlation with the amount of Al dissolved by the citrate treatment and increased with increasing soil pH (H₂O) from 4.5 to 5.2 and with decreasing exchangeable Al in soil.
Formation of a hydroxy-Al sheet partially bonded with Si-tetrahedra was suggested as a possible model of the interlayer structure of PIV. The differences between PIV in the studied Inceptisols and other soils are discussed.     

Source minerals and formation of partially interlayered vermiculites in Dystrochrepts derived from Tertiary sediments

The formation of partially interlayered vermiculite (PIV) was studied in six Dystrochrepts derived from Tertiary sediments. Mineralogy of silt and clay fractions of gravel and fine earth separated from surface and subsurface samples were determined by X-ray diffraction. PIV, mica, vermiculite and regularly interstratified 1:1 PIV/chlorite (PIV/Ch(l:l)) were the dominant clay minerals. The contents of these minerals were compared between the specific particle-size fractions of gravel and fine earth for each sample and the difference was interpreted in terms of mineral transformation associated with soil formation. PIV was formed from mica and PIV/Ch(l:l) in soils with a pH(KCl) of 3.5 to 4.0 and little organic matter. Vermiculite was formed from mica in surface soils with a low pH (pH(KCl) 3.5) and abundant organic matter. PIV would form directly from mica without an intermediary phase of vermiculite and form from PIV/Ch(l:l) by partial dissolution of interlayers in chlorite layers.     

In vitro antibacterial activity of the combination of sulphadiazine and trimethoprim on bacterial fish pathogens

Abstract. The in vitro bacteriostatic activity of a combination of sulphadiazine (SDZ) and trimethoprim (TMP) against representative bacterial fish pathogens was studied. In general, the minimum inhibitory concentrations (MIC) of TMP were much smaller than comparable values for SDZ. When SDZ and TMP were combined, the bacteriostatic effect was enhanced in a synergistic manner for all bacteria tested except Pseudomonas fluorescens . The synergism was most remarkable in the case of bacterial strains that were sensitive to the action of SDZ alone. This degree of synergism was observed when the ratios of SDZ and TMP in combination were in the range of 1:1 io 5:1. The MIC of SDZ plus TMP combined was less than 3.13 μg/ml for SDZ resistant strains and as low as 0.2 to 0.78 μ/ml for SDZ sensitive strains. The possible usefulness of a combination of these two compounds for therapy or control of bacterial fish disease is discussed.     

A new thiamine derivative,S-benzoylthiamine O-monophosphate

S-Benzoylthiamine O-monophosphate has been synthesized, and its physicochemical and biological properties have been investigated. It is a stable crystalline substance, it exerts thiamine activity approximately equivalent to that of thiamine hydrochloride in thiamine-requiring microorganisms, and it is easily absorbed in organisms, particularly by oral administration.     

Effect of Low-Dose Human Interferon-alpha on Shipping Fever of Thoroughbred Racehorses

To assess the effect of human interferon-alpha (IFNα) on shipping fever of Thoroughbred racehorses subjected to long-distance transportation, an IFNα preparation was orally administered to 48 horses three times (once daily, 3 successive days) before transportation (IFNα group). In the control group (25 horses), maltose was administered in the same way. These treatments induced no abnormal findings in Thoroughbred racehorses before transportation. Immediately after transportation, significant increases in rectal temperature were observed in both treatment groups, whereas the rectal temperature of the IFNα group tended to be lower than that of the control group. Although WBC, Fbg, and SAA immediately after transportation were significantly increased due to transportation in both groups, the extent of the increases in the IFNα group was significantly smaller than in the control group. Long-distance transportation had a relatively profound impact on Thoroughbred racehorses, which was mitigated by IFNα treatment.     

Effect of presence of rumen protozoa on degradation of cell wall constituents in gastrointestinal tract of cattle

The cell wall constituents of feces from three faunated and three defaunated (without ruminal ciliate protozoa) cattle fed on a Sudangrass hay and concentrate mixture (8:5) were analyzed. There was little difference in digestibility of dry matter between the faunated and defaunated cattle. Analysis of the fecal sugar residues revealed that the digestibilities of arabinose and galactose, derived from pectic and hemicellulosic substances located within the compound middle lamella, were higher in the defaunated cattle than the faunated cattle (P < 0.05), whereas the digestibilities of glucose and xylose, derived mainly from cellulose and xylan, were unchanged by the removal of protozoa. The digestibility of lignin was not different between the faunated and defaunated cattle, but those of mannose and p‐coumaric acid were lower in the defaunated than in the faunated animals (P < 0.05). The ratio of primary cell wall to secondary cell wall in fecal plant materials was lower for the defaunated than for the faunated cattle. The results in this study suggested that the defaunation enhanced the microbial degradation of the thin cell walls, but depressed the degradation of developed cell walls.     

Effect of different organic amendments on the resistance and resilience of the organic matter decomposing ability of soil and the role of aggregated soil structure

The effect of organic amendment on the resistance and resilience of the organic matter decomposing activity was compared between soils amended with compost and with chemical fertilizers. The impact of metam sodium disinfection on cellulose-decomposing activity and on the number of nematodes in three types of soils was periodically measured. In an andosol, cellulose-decomposing activity was significantly suppressed by soil disinfection only in the chemically fertilized soil (CF-soil) and not in the soils to which cow manure compost and okara (the residue in tofu production)/coffee compost was added. In a brown lowland soil, cellulose-decomposing activity was significantly suppressed by soil disinfection in the CF-soil, but not in the soils to which higher amounts of cow manure compost and pig manure compost had been added. In a red-yellow soil, cellulose-decomposing activity was significantly suppressed by soil disinfection in all soils, but its resilience was higher in the soils to which cow manure compost or coffee compost was added compared with the CF-soil. Total numbers of nematodes were markedly decreased by soil disinfection in all soils. These results may suggest that the resistance and resilience of cellulose-decomposing activity against soil disinfection were enhanced by organic amendments, while disinfection had fatal effects on soil nematodes. In most of the organically amended soils, the mean weight diameters of aggregates were larger compared with the CF-soils, suggesting that highly structured soil pore networks may provide shelters for the soil microbes responsible for cellulose decomposition against disinfection. This hypothesis was supported by the result that the resistance of cellulose-decomposing activity against soil disinfection decreased when the soil structure was destroyed by grinding in a mortal and pestle.     

The complete mitochondrial genome of the domestic red deer (Cervus elaphus) of New Zealand and its phylogenic position within the family Cervidae

We determined the complete nucleotide sequence of the mitochondrial genome of the semidomestic red deer (Cervus elaphus) of New Zealand. The genome was 16 357 bp long and contained 13 protein‐coding genes, 12SrRNA, 16SrRNA, 22 tRNAs and a D‐loop as found in other mammals. Database homology searches showed that the mitochondrial DNA (mtDNA) sequence from the New Zealand semidomestic deer was similar to partial mtDNA sequences from the European, Norwegian (C. e. atlanticus) and Spanish red deer (C. e. hispanicus). Phylogenetic analysis of the mitochondrial protein‐coding regions revealed two well‐defined monophyletic clades in subfamilies Cervinae and Muntiacinae. However, red deer and Sika deer were not found to be close relatives. The analysis did identify the red deer as a sister taxon of a Samber/Sika deer clade, although it was more closely related to the Samber than the Sika group.