Can nuclear aquatic environmental DNA be a genetic marker for the accurate estimation of species abundance?

The Science of Nature - We present the first study that compares phenological variation in parasite load and inflammatory response in a lizard with asynchronous male and female gonadal cycles....     

Causes of decreased reference evapotranspiration and pan evaporation in the Jinghe River catchment, northern China

This study focused on the changes of reference evapotranspiration (ET₀) and pan evaporation (ET_pan) to study the impacts of climate change on the hydrological cycle in the Jinghe River catchment. Based on the Penman–Monteith equation, the ET₀ was calculated. The temporal trend and spatial distribution of ET₀ and E_pan measured with a 20-cm pan were examined at the 14 stations during 1957–2005. The effects of meteorological factors on the variation of ET₀ were determined by analyzing the trends in themselves with comparison between original climate and detrended climate scenarios and then their sensitivity to ET₀. Both the ET₀ and E_pan showed remarkable decreasing trends from 1957 to 2005 and their decreasing rate was 40.9 and 17.7 mm per 10 years, respectively. Trend analysis of meteorological factors exhibited that the reduction in ET₀ and ET_pan was principally caused by both significant decreases in wind speed and sunshine hours. Furthermore, the decreasing trend of ET₀ was mainly dominated by the significant decrease in wind speed with high sensitivity, to a less extent, by the decrease in net radiation. Although relative humidity is one of the most sensitive variables, its effect on ET₀ was negligible because of its temporal constancy. The contribution of wind speed reduction to decreased ET₀ has increased from 50 to 76.1%, but net radiation, by contrast, decreased from 50 to 23.9%.     

Formation of chloroform and carbon tetrachloride in foods treated with sodium hypochlorite

The formation of chloroform and carbon tetrachloride during the treatment of fresh vegetable homogenate with sodium hypochlorite was studied.When a n-hexane extract of the reaction mixture of fresh vegetables and sodium hypochlorite was analysed by gas chromatography, chloroform and carbon tetrachloride were detected, and many unidentified peaks were also observed. The formation conditions of chloroform and carbon tetrachloride were studied. The mechanism of chloroform formation may be different from that of carbon tetrachloride according to the study of pH on the formation of both compounds. The formation of chloroform is much greater than that of carbon tetrachoride.     

土壤和沉积物中痕量元素的ICP质谱法测定

人们对环境中污染物 (特别是重金属 )的“安全”水平的关注与日俱增 ,要分析的元素更多 ,浓度更低 ,从而暴露出当前所用分析技术的局限性 ,需要进一步提高分析方法的灵敏度和可分析的元素数量 .尽管ＧＦＡＡＳ (石墨炉原子吸收光谱 )和ＩＣＰ ＯＥＳ (感耦等离子体发射光谱 )仍是环境元素分析中最常用的技术 ,但ＩＣＰ ＭＳ (等离子体质谱 )是具有更高灵敏度的分析技术 ,不久肯定会被普遍接受 .ＨＰ 4 50 0台式ＩＣＰ质谱仪具有实际惯常分析应用所必需的可靠性和易于操作 ,可进行亚ｎｇ·ｍｌ- 1级 (ｐｐｂ)浓度水平的多元素快速分析 .本篇…     

Venoms from six species of marine fish: lethal and hemolytic activities and their neutralization by commercial stonefish antivenom

A specimen of the stonefish Synanceja verrucosa was captured in Okinawa in March 1988. Live specimens of the scorpionfish Inimicus japonicus were purchased from the Tokyo Central Wholesale Market in November 1988 and those of four species of zebrafish Pterois lumulata, P. volitans, P. antennata and Dendrochirus zebra from an aquarium in December 1988. Crude venoms were extracted from dorsal spines of the six species. All venoms exhibited lethal activity against mice and hemolytic activity specific for rabbit erythrocytes. The lethal activity (or hemolytic activity) of each venom was very unstable to freezing, lyophilization and heating. Both lethal and hemolytic activities of S. verrucosa venom were remarkably neutralized by the commerical stonefish (Synanceja trachynis) antivenom. This antivenom was also effective, to some extent, in counteracting the other venom activities. The neutralizing capacities of the antivenom were calculated to be 7310 LD₅₀ ml^-1 for S. verrucosa venom and 1 220 to 2 990 LD₅₀ ml^-1 for the other venoms. Results of neutralization tests suggest that venoms from the six species were comparable in terms of antigenecity.     

Determination of PCDD/Fs and dioxin-like PCBs in fish oils for feed ingredients by congener-specific chemical analysis and CALUX bioassay

The present research was intended to determine the suitability of the CALUX assay as a screening method for dioxins in fish oil used as a feed ingredient in Japan. Alteration of TEQ in fish oil according to newly proposed toxic equivalency factors (TEF) is also discussed. In the analysis, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in 41 fish oil samples were determined by using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) and CALUX bioassay. The mean TEQ values derived from 1998 WHO-TEF of PCDD/Fs and DL-PCBs were 2.6 and 9.9 pg g(-1) (ww), respectively. The levels of TEQ derived from the recently re-evaluated 2005 WHO-TEF were slightly lower than those of the former in both groups. Notably, the contribution of mono-ortho DL-PCBs to total 2005 WHO-TEQ was considerably decreased compared to the case of 1998 WHO-TEQ, resulting from the reduction in its TEF values, while the non-ortho DL-PCBs contribution was increased. The mean TEQ determined by CALUX assay for PCDD/Fs was approximately three times higher, whereas DL-PCBs was approximately two times lower than WHO-TEQ determined by HRGC/HRMS; the sum of PCDD/Fs and DL-PCBs was very similar by both methods. The correlation coefficients of TEQ between the CALUX assay and HRGC/HRMS analysis were 0.84, 0.89, and 0.90 for PCDD/Fs, DL-PCBs, and the sum, respectively. These results suggest that the CALUX assay is a very useful method for the screening of dioxin-related compounds in fish oils.     

Accumulation of polychlorinated naphthalenes in domestic animal related samples

Concentrations of polychlorinated naphthalene (PCN) congeners were measured in domestic animal related samples such as feed ingredients, mixed feed and animal fat. Mean concentrations of total PCNs in feed ingredients ranged from 500 to 1500 pg g(-1) lipid wt with a high concentration found in fish meal. Total PCN concentrations were similar among mixed feeds, which ranged from 98 to 110 pg g(-1) lipid wt. The total PCN concentration in chickens was more than twice the amount in pigs. Tetra-CNs were the predominant homologues in all samples. Biomagnification of higher chlorinated PCN congeners, especially penta- and hexa-CNs, was a few fold greater in chickens compared to pigs. The estimated concentrations of 2,3,7,8-tetrachloro dibenzo-p-dioxin equivalents (TEQs) of some selected PCNs in feed ingredients, mixed feeds, chickens and pigs were 0.008 to 0.063, 0.001 to 0.002, 0.033 and 0.011 pg g(-1) lipid wt, respectively. Based on predicted luciferase inducing potency for each PCN congener, the estimated PCN-TEQs in feed ingredients and animal fat were similar to those that were estimated from selected PCNs.     

Removal of PCDDs/DFs and dl-PCBs in MWI fly ash by heating under vacuum

Temperature dependence of PCDD/DF and dioxin-like polychlorinated biphenyl (dl-PCB) concentrations in fly ash from a municipal waste incinerator (MWI) heated under vacuum has been investigated as a function of sample temperature ranging from T(s)=425 to 800 K to find out if PCDDs/DFs in fly ash evaporate and are trapped in a liquid nitrogen-cooled trap. The results show that more than 99.98% of PCDDs/DFs in TEQ is removed from fly ash by vacuum heat treatment at T(s)>650 K for 4 h. Almost no PCDDs/DFs were detected in the liquid nitrogen-cooled trap. Homologue distributions indicate that dechlorination/hydrogenation (DCH) reactions proceed in fly ash at T(s)>450 K. Arrhenius rate parameters for the DCH reactions have been determined for each homologue assuming that only DCH reactions occur. The fly ash heated under vacuum at 650 or 800 K was reheated at 573 K (300 degrees C) in a stream of dry or humid air to see how much PCDDs/DFs and dl-PCBs are regenerated. We have found that (1) PCDDs/DFs are regenerated in both 650 K and 800 K treated fly ash, whereas dl-PCBs are regenerated in 650 K treated fly ash, (2) formation of PCDFs predominates over that of PCDDs or dl-PCBs, and (3) less chlorinated homologues are abundant for PCDDs/DFs and dl-PCBs.     

Sequential Determination of Trace Metals in Sea Water by Inductively Coupled Plasma Mass Spectrometry After Electrothermal Vaporization of their Dithiocarmabamate Complexes in Methyl Isobutyl Ketone

A sensitive method for sequential determination of V, Mn, Fe, Co, Ni, Cu, Zn, Mo and Sb in sea water using an inductively coupled plasma mass spectrometry (ICP-MS) after electrothermal vaporization of their dithiocarbamate complexes in methyl isobutyl ketone (MIBK) has been investigated. All analyte elements were simultaneously concentrated 20 fold in a single extract and introduced into the plasma using a graphite rod electrothermal vaporizer (ETV). A sensitivity enhancement due to a chemical modification using a mixed modifier of palladium nitrate and magnesium nitrate was observed for all analyte elements. The limits of detection of the method ranged from 2 ng l-1 for Co to 329 ng l-1 for V. For the replicate determinations of the analyte elements in a sea water sample, the repeatability was within 10% (as a coefficient variation), except for V (12.8%). The recovery test performed on a sea water sample resulted in values ranging from 87% for Sb to 119% for V. With the exception of Mo, the application of this method for the determination of the analyte elements in sea water samples collected from the surface to the depth of 5000 m at the sampling station of 34°12.08N, 141°57.50E (Oct. 12, 1994) in the northwest Pacific Ocean resulted in vertical distributions and concentration ranges which were in a good agreement with those reported in literatures.