Contemporary conservationist (12)

Outdoor recreation is often supposed to have an important impact on wildlife, although this assumption has not been tested very often. The resulting lack of knowledge becomes apparent in situations where parties with conflicting interests disagree on the number of visitors an area can sustain without major repercussions.In 1980 the possible effects of recreation intensity upon bird densities were studied in seven study plots adjacent to urban residential areas in The Netherlands. Of the 31 bird species found, only 13 could be studied in detail, being present in at least 20 territories. Significant negative correlations between recreation intensities and bird densities were found for 8 of these 13 species.The slopes of the regression lines enabled us to rank the 8 species in a sequence of decreasing susceptibility. The results indicate that the disturbance is caused rather by the recreation intensity during the week than by the recreation intensity at weekends.     

Contemporary conservationist (10)

The extremely high serum potassium levels of dugongs that have been chased with a speedboat, harpooned and drowned suggest that they may be susceptible to the capture stress syndrome. The resultant implications for research and management policy are discussed.     

Occurrence of fumonisins B(2) and B(4) in retail raisins

Concerns that raisins may be contaminated by fumonisins stem from the persistent occurrence of Aspergillus niger spores on raisins and the recent discovery of fumonisin production by A. niger on grapes, which leads to the widespread occurrence of fumonisin B(2) in wine. This study presents an LC-MS/MS survey of fumonisins in retail raisins. In 10 of 21 brands collected in Denmark, Germany, and The Netherlands, fumonisins B(2) and B(4) were detected at levels up to 13 and 1.3 μg/kg, respectively. Only fumonisin B(2) has been detected in wine, so the presence of fumonisin B(4) in raisins suggests that the fumonisins are produced mainly during the drying process concomitant with the decreasing water activity. Analysis of multiple packages from one manufacturer showed a 3-fold package-to-package variation, suggesting that a few raisins per package are contaminated.     

猪Tool-like Receptor 4(TLR4)的定位和组织表达

通过辐射杂交板的方法将猪的Tool-like Receptor 4(TLR4)定位在SSC1q2.9→q2.13,它与SW1957紧密连锁(15cR LOD score 15.16)。用RT-PCR表明TLR4mRNA在猪的睾丸、灰质、肌肉、白质、肾脏、心脏、小肠、胸腺、淋巴结、脾、肺和肝脏等各种组织中广泛表达,在肺中的表达量最高。TLR4mRNA在肺中的表达量可能与猪肺部疾病有关。     

Impacts of (NH4)2SO4 Deposition on Norway Spruce (Picea Abies [L.] Karst) Roots

The effects of enhanced (NH₄)₂SO₄ (NS) deposition on Norway spruce (Picea abies [L.] Karst) fine root biomass, vitality and chemistry were investigated using root-free in-growth cores reproducing native organic and mineral soil horizons. The cores were covered and watered every 2 weeks with native throughfall or throughfall supplemented with NS to increase deposition by 75 kg ha^-1 a^-1 NH₄ ⁺-N (86 kg ha^-1 a^-1 SO₄2--S). The in-growth cores were sampled after 19 months and assessed for root biomass, necromass, length, tip number, tip vitality and fine root chemistry. Root biomass and fine root aluminium (Al) concentration were negatively correlated, but NS deposition had no effect on root growth or root tip vitality. NS deposition caused increased fine root nitrogen (N) concentrations in the organic horizon and increased Calcium (Ca) concentrations in the mineral horizon. Fine root biomass was higher in the organic horizon, where fine root Al and potassium (K) concentrations were lower and Ca concentrations higher than in the mineral horizon. Results highlighted the importance of soil stratification on fine root growth and chemical composition.     

14C-苄嘧磺隆的合成

用Ba14CO3为原料,合成14C-氰化钠、硝酸胍和苄基磺酰胺等中间体,最终得到14C-苄嘧磺隆产品.放化收率为14.6%,放化纯度大于95%,放射性比活度为0.781 μCi/mg(28.897kBq/mg).     

硫酸铈(Ce~(4+))剂量计的改进

本文采用在硫酸铈(Ce~(4+))体系中,加入硫酸铜(Cu~(2+))的方法,改进铈(Ce~(4+))剂量体系的稳定性。实验测定Ce~(4+)/Cu~(2+)体系中,Ce~(4+)的摩尔吸光度5643±451.M~(-1).cm~(-1)。在150—4×10~4Gy范围内,用三种Ce~(4+)浓度,测定水深5厘米校准点的G(Ce~(3+))为2.20±0.04。研究表明,G(Ce~(3+))值随辐照温度的上升而线性下降,测得辐照温度修正系数为-(5.13±0.07)×10~(-3)/℃。在Ce~(4+)溶液体系中,加入0.1M Cu~(2+),使剂量体系趋于稳定。对非限束~(60)Coγ源,水中校准点吸收剂量不确定度±3.3%,重复性好于±2.5%。Ce~(4+)/Cu~(2+)适宜作为辐射加工中高剂量区的参考剂量计。     

Nitrogen cycling in two Norway spruce (Picea abies) ecosystems and effects of a (NH4)2SO4 addition

Nitrogen cycling in two Norway spruce (Picea abies (L.) Karst.) ecosystems in the ARINUS experimental watershed areas Schluchsee and Villingen (Black Forest, SW Germany) and initial effects of a (NH₄)₂SO₄ treatment are discussed. Although N reserves in the soils are similar and atmospheric N input is the same low to moderate level characteristic for many forested areas in SW Germany, N export by both seepage and streamwater differs considerably. At Villingen, deposited N is almost totally retained in the ecosystem, whereas at Schluchsee N export is the order of the input. This is explained by differences in forest management history. The Villingen site had been subject to excessive biomass export (e.g., litter raking) leading to unfavorable microbial transformations in the soil. In contrast, as a ‘relic’ of the former beech stand, the Schluchsee site is characterized by high biological activity in the soil with vigorous nitrification despite low pH values. Accordingly, the two ecosystems responded differently to the additional N input (150 kg NH₄ ⁺ -N ha^?1 as (NH₄)₂SO₄). Nitrification starting immediately in the Schluchsee soils led to continued Al mobilization and leaching of basic cations and NO₃ ^?. The availability of Mg, already deficient before treatment, further decreased due to Mg leaching and marked N uptake by the stand. In contrast, most of the added N in Villingen was immobilized in the soil. Hence, uptake by the stand and leaching of NO₃ ^? and cations was correspondingly lower than at Schluchsee. The results emphasize the problems associated with the definition of generally applicable values for ‘critical loads’ of N deposition.     

Synthesis and antifungal activities of alkyl N-(1,2,3-thiadiazole-4-carbonyl) carbamates and S-alkyl N-(1,2,3-thiadiazole-4-carbonyl) carbamothioates

A series of alkyl N-(1,2,3-thiadiazole-4-carbonyl) carbamates and S-alkyl N-(1,2,3-thiadiazole-4-carbonyl) carbamothioates with unsubstituted or monobrominated straight chain alkyl groups were synthesized and evaluated as fungistatic agents against Gibberella zeae and Alternaria kikuchiana. These compounds showed variable antifungal activities at concentrations of 5 and 50 microg/mL. The results showed that antifungal activities depended on the length of the alkyl chain with the optimal chain length of 6-11 carbons. Carbamic acid, (1,2,3-thiadiazole-4-ylcarbonyl)-, hexyl ester (4) showed a strong fungistatic activity against A. kikuchiana at both concentrations, with 90.7 and 54% growth inhibition at 50 and 5 microg/mL, respectively. Carbamic acid, (1,2,3-thiadiazole-4-ylcarbonyl)-, heptyl ester (5); Carbamic acid, (1,2,3-thiadiazole-4-ylcarbonyl)-, octyl ester (6); and Carbamic acid, (1,2,3-thiadiazole-4-ylcarbonyl)-, undecyl ester (9) showed strong fungistatic activity against G. zeae at both concentrations. Their growth inhibitions against G. zeae at the concentration of 5 microg/mL were 78, 63, and 59%, respectively.     

平衡栽培体系中的农业栽培措施(四)

1平衡施肥（续三） 1．4微生物肥料 微生物肥料又称生物肥料、菌肥、接种剂，是一类以微生物生命活动及其产物导致农作物得到特定肥料效应的微生物活体产品。微生物肥料产品分微生物菌剂和微生物肥料两大类，前者是单纯的微生物发酵产品，后者则是由微生物菌剂与化肥或有机肥混配而成的产品，包括复合微生物肥料和生物有机肥。     

Bildung sekundärer Al-(Fe-)Chlorite

Genesis of Secondary Al-(Fe-)Chlorites Comparing the results of soil investigations with those obtained from laboratory syntheses it was concluded that secondary Al-Fe-chlorites in soils of moderate cool-warm-humid climates mainly develop through protonisation of Al and Fe in the mineral structure of expanded dioctahedral vermiculites with subsequent hydrolysis in the interlayer space. In this process characteristics of the mineral itself (e.g. layer charge) as well as carbonic acid and soil organic acids (as proton suppliers) are the most important factors. From this, the further conclusion was drawn that in the pH-range 6, 5–6 secondary chlorites begin to develop increasingly until pH5 (development conditions) and in the pH-range 5–4,5“conservation conditions” exist. - At pH<4,5 secondary chlorites are unstable (dissolution conditions) through protonisation of Al-Fe-hydroxy polymers (reverse of hydrolysis) with subsequent solubilization and leaching especially through complexation by soil organic acids. - As remaining minerals in this weathering sequence smectites occur, resulting from the decrease of layer charge in vermiculites through the chloritization process, thus indicating that chloritization may be an important process for the genesis of smectites under acid weathering conditions.     

N-Nitrosation of myosmine yields HPB (4-hydroxy-1-(3-pyridyl)-1-butanone) and NNN (N-nitrosonornicotine)

N-Nitrosonornicotine (NNN) is formed by synthetic or biological N-nitrosation of the tobacco alkaloid nornicotine. Following metabolic activation of NNN, DNA and protein adducts are formed releasing 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB), an actual biomarker to differentiate between tobacco smokers and passive smokers. NNN and HPB can be prepared in a new one-step reaction by N-nitrosation of the nicotinoid myosmine which has been found not only in tobacco but also in nut products. The reaction was tested also in human gastric juice. The formation rate of NNN and HPB depends on the pH value in the reaction solutions. This is important under the aspect of myosmine uptake by humans from other biological sources and subsequent biological activation. The new reaction pathway indicates that human exposure to nicotinoid nitrosation products seems to be not restricted exclusively to tobacco.     

Anthracene influence on (15NH4)2SO4 fertilization of wheat seedlings

The influence of the addition of anthracene (1 μg anthracene g^?1 soil) in N transformations following (¹⁵NH₄)₂SO₄ fertilization (200 mg N g^?1 soil) was investigated in wheat pots by quadrapole mass-spectrometry. The dry matter yield at harvesting (after 16 days) was not statistically affected (P=0.05) by anthracene addition. The total amount of N from the fertilizer taken up by wheat seedings in 16 days was 29 and 26.8% of the added N in the absence and in the presence of anthracene, respectively, but the difference was not significantly different at level P=0.05. In order to investigate more deeply the effect of anthracene on the N cycle in the soil-plant system, the first-order rate constants of N mineralization, N immobilization, nitrification and N plant uptake have been determined according to a ¹⁵N + ¹⁴N soil-plant model. The comparison of the constants showed that organic N mineralization, nitrification and plant uptake proceeded at the same rate, while a small different rate (P=0.05) was shown by N immobilization. In fact, the N immobilization constant increased from 0.14±0.012 to 0.21±0.014 day^?1 as a consequence of anthracene addition.     

4-(4-羟基)苯乙基-1,2-二羟基苯对土壤脲酶的抑制作用

正尿素是我国农作物的主要氮肥之一,但由于土壤微生物所产生脲酶的作用,尿素施入土壤后,会迅速分解转化成氨气而造成流失,使得农作物对尿素的利用率不到40%[1]。尿素无效分解,不仅降低肥效,而且过量产生氨,一方面会在各种因素的作用下转化为硝酸盐,对地下水造成污染[2-3],成为环境恶化、人类患癌症的主要因素之一[4];另一方面会对农作物生长造成不利影响,严重时会导致烧苗。土壤中氨含量增加,还会对正在发芽的种子产生毒性[5]。     

Contemporary Trend in Erosion of Arable Ordinary Chernozems (Haplic Chernozems (Pachic)) within the Volga Upland (Saratov Oblast,Russia)

Eurasian Soil Science - The current trend in erosion rate of ordinary chernozems in Saratov oblast has been assessed. Detailed studies have been performed in a small catchment area of the Bolshoi...