Simultaneous determination of antimony and bismuth in soils by continuous hydride generation—atomic absorption spectrometry

A method for the simultaneous determination of Sb and Bi in soils using an automated hydride generation system with an electrically heated quartz cell atomizer, and an atomic absorption spectrophotometer is described. Five g of the air-dried soil was placed in a 100 mL Erlenmyer flask fitted with a Liebig condenser and boiled gently with 20 mL 6 M HCl for 1 hr on a sand bath. The extract was then filtered into a 100 mL volumetric flask. The two elements in the sample solution (<30 mL) placed in a 50 mL volumetric flask are prereduced by potassium iodide and ascorbic acid solutions. Reduction of Sb and Bi ions to stibine and bismuthine is obtained by sodium tetrahydroborate solution. Detection limits (S/N = 2) are 7 ng g^?1 dry soil for Sb and 0.7 ng g^?1 dry soil for Bi. The effects of 19 diverse ions on the absorbances of Sb and Bi were investigasted, and it was found that the errors by these ions will be within 5% in the ordinary unpolluted or even polluted soils. In order to examine the accuracy of the proposed method, Sb and Bi in the four Canadian reference soils and NBS-4355 from the National Bureau of Standards in the USA were determined. The values obtained in this work are close to the recommended or the not-certified values. The amounts of Sb, Bi and the related elements in the soils near a smelter were also analyzed.     

Sex determination of sika deer (Cervus nippon yesoensis) using nested PCR from feces collected in the field

We describe a method for determining the sex of sika deer (Cervus nippon yesoensis) from feces collected in the field. Using a nested polymerase chain reaction (nested PCR), partial sequences of the sex determination region of the Y chromosome (SRY) gene and X zinc finger protein (ZFX) gene were amplified. In 19 individuals with sex information, the correct sex was successfully detected and sequences of target amplicons were completely matched between muscle and feces from the rectum. Among 75 fecal samples collected noninvasively in the field, 68-71 samples (90.7-94.7%) yielded successful sex determinations. Using this technique, feces collected in the field would enhance the utility of genetic analysis. As a result, instead of biomaterials, these samples can serve as new or alternative materials. Finally, it can be expected that this technique will contribute to reveal in advanced detail of the population dynamics and genetic diversity that needed to carry out effective population control and to reduce the extinction risk of sika deer.     

Relationships between ammonia oxidizers and N2O and CH4 fluxes in agricultural fields with different soil types

Nitrous oxide (N₂O) is a greenhouse gas that contributes to the destruction of stratospheric ozone, and agricultural soil is an important source of N₂O. Aerobic soils are sinks for atmospheric methane (CH₄), a greenhouse gas. Ammonia monooxygenase (AMO) can oxidize CH₄, but CH₄ is mostly oxidized by methane monooxygenase (MMO), and CH₄ oxidation by AMO is generally negligible in the soil. We monitored the N₂O and CH₄ fluxes after urea application in fields containing different soils using an automated sampling system to determine the effects of environmental and microbial factors on the N₂O and CH₄ fluxes. The soil types were Low-humic Andosol (Gleyic Haplic Andosol), yellow soil (Gleyic Haplic Alisol) and gray lowland soil (Entric Fluvisol). Cumulative N₂O emissions from the yellow soil were higher than those from other soil types, although the difference was not significant. The CH₄ uptake level by Andosol was one order of magnitude higher than that by other soils. There were significant relationships between the ammonia oxidation potential, AOB and AOA amoA copy numbers, and the CH₄ uptake. In contrast, the gene copy numbers of methane-oxidizing bacteria (MOB) pmoA were below the detection limit. Our results suggested that the AMOs of AOB and AOA may have more important roles than those previously considered during CH₄ oxidation in agricultural soils treated with N fertilizers.     

Antibacterial abilities of intestinal bacteria from larval and juvenile Japanese flounder against fish pathogens

The present study was undertaken to examine the antibacterial abilities of intestinal bacteria isolated from juveniles and larvae of Japanese flounder Paralichthys olivaceus . Newly hatched larvae of flounder were held in a 100 L plastic circular tank and fed rotifiers, Artemia nauplii and commercial feeds, depending on the developmental stage of the fish. Genera Aeromonas , Moraxella and Vibrio were predominantly isolated from the intestinal tracts of Japanese flounder at larval and juvenile stages, whereas Aeromonas , Bacillus , coryneforms, Moraxella , Pseudomonas and Vibrio were detected at high densities in live diets and artificial feeds. Antibacterial bacteria accounted for 1.7–24.3% of the intestinal isolates against Lactococcus garvieae , Pasteurella piscicida , Vibrio anguillarum and V. vulnificus . In particular, as much as 53.3% of Vibrio spp. other than Vibrio -swarmer isolated from 197-day-old juveniles inhibited the growth of P. piscicida . These results suggest that intestinal bacteria having antibacterial activity play a role in the prevention of infectious diseases.