Bacterial degradation of monocrotophos and phyto- and cyto-toxicological evaluation of metabolites

The bacterium Serratia marsescens strain JAS16 was isolated from agricultural soil which had prior exposure to monocrotophos for three years. The strain JAS16 tolerated up to 1200 mg L^–1 monocrotophos and degraded the insecticide (1000 mg L^–1) at a degradation rate constant of 136 d^?1 (DT₅₀ = 3.7 d). In soil, the degradation rate constant was 105 d^?1 (DT₅₀ = 4.8 d). A schematic pathway is being proposed from the degraded products derived from gas chromatography--mass spectrometry (GC-MS). The phytotoxicity of degradation products to Vigna radiata, Vigna unguiculata, and Macrotyloma uniflorum and the genotoxicity to Allium cepa roots were found to be low. A cost-effective powder-based formulation was achieved with the isolate. The isolate remained viable during the storage and also multiplied with a higher colony forming units (CFU) load g^–1 for over a period of seven weeks of storage.     

Biofilm-overproducing Bacillus subtilis B12ΔYwcc decreases Cd uptake in Chinese cabbage through increasing Cd-immobilizing related gene abundance and root surface colonization

Biofilm-producing bacteria can decrease Cd uptake in vegetables, but mechanisms underlying this effect are poorly characterized. In this study, two mutant strains B12ΔYwcc and B12ΔSlrR were constructed from a biofilm-producing Bacillus subtilis strain B12. Then, the impacts of strain B12 and its high biofilm-producing mutant strain B12ΔYwcc and low biofilm-producing mutant strain B12ΔSlrR on Cd availability and uptake in Chinese cabbage and the related mechanisms were investigated in the Cd-polluted soil. Strain B12 and its mutants B12ΔYwcc and B12ΔSlrR increased the dry biomasses of edible tissues by 54%–130% compared with the controls. Strain B12 and its mutant B12ΔYwcc reduced the soil available Cd content by 36%–50% and root and edible tissue Cd contents by 23%–50% compared with the controls. Furthermore, the mutant strain B12ΔYwcc reduced the edible tissue Cd content by 40% and increased the polysaccharide content by 23%, invertase activity by 139%, and gene copies of the cumA by 4.5-fold, epsA by 7.1-fold, and cadA by 4.3-fold, which were involved in Cd adsorption in the rhizosphere soils, respectively, compared with strain B12. The polysaccharide content and cumA, epsA, and cadA gene copy numbers showed significantly reverse correlations with the available Cd content. Notably, the mutant strain B12ΔYwcc showed better ability to colonize the vegetable root surface than strain B12. These findings demonstrated that the biofilm-overproducing mutant strain B12ΔYwcc increased the polysaccharide production and Cd-immobilizing related cumA, epsA, and cadA gene copies, resulting in lower Cd availability and accumulation in Chinese cabbage in the Cd-polluted soil.     

生物表面活性剂的产生及其在环境污染治理中的应用

生物表面活性剂是由微生物在一定培养条件下分泌的次级代谢产物,属于绿色环保的新型表面活性剂。文章在综述了生物表面活性剂的类型、主要产生菌、生产方法及其化学特性等基础上,重点介绍了生物表面活性剂在环境污染治理方面的应用,并探讨了今后生物表面活性剂的研究方向及应用前景。     

Detection of rubella virus in fetal and placental tissues and in the throats of neonates after serologically confirmed rubella in pregnancy

From 35 therapeutic abortions performed because rubella had occurred at 2–19 weeks of pregnancy, 120 fetal organs, 12 specimens of mixed products of conception, and 15 placentae were tested for rubella virus. Virus was isolated from 10 out of 11 fetuses (91 per cent) from women infected at 2–8 weeks, from 5 out of 8 (63 per cent) infected at 9–10 weeks, and from 2 out of 16 (13 per cent) infected at 11–19 weeks. Hybridization tests for viral RNA on 39 fetal organs from eight cases revealed infection in four additional fetuses. Virus was isolated from only 3 out of 15 aborted placentae, but hybridization tests on six placentae revealed infection in three additional specimens. Hybridization was superior to virus isolation for detecting rubella infection in products of conception and is therefore potentially the better method for examining chorionic villus biopsies. Rubella virus was isolated from the throats of 4 out of 9 infants (44 per cent) infected during the first 12 weeks of gestation, but from none of 13 infected after 17 weeks. Infants in the latter group are unlikely to infect susceptible contacts.     

Female sex pheromone of Ostrinia orientalis – throwing a light on the relationship between O. orientalis and the European corn borer, O. nubilalis

Summary. The sex pheromone of Ostrinia orientalis (Lepidoptera: Crambidae) was analyzed by gas chromatography–electroantennographic detection (GC–EAD), GC–mass spectrometry and a series of bioassays. Three EAD-active compounds were detected in the female sex pheromone gland extract, and identified as tetradecyl acetate (14:OAc), (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (E)-11-tetradecenyl acetate (E11-14:OAc). The titers (ratio) of 14:OAc, Z11-14:OAc and E11-14:OAc in 3-day-old virgin females were 0.49 ng (10), 4.86 ng (98) and 0.10 ng (2), respectively. In a wind-tunnel bioassay, the 98:2 blend of Z11- and E11-14:OAc, but not Z11-14:OAc alone, elicited the same male behavioral responses as virgin females and crude gland extracts. 14:OAc was inactive by itself, and did not show any synergistic effect on the binary blend. Field trapping experiments also confirmed the attractiveness of the binary blend to O. orientalis males. Based on these results, we concluded that the sex pheromone of O. orientalis is a 98:2 mixture of Z11-14:OAc and E11-14:OAc. This sex pheromone is very similar to that of the Z-type European corn borer, O. nubilalis. The present finding raises the question of whether O. orientalis , which is indistinguishable from O. nubilalis based on external morphology, is a biologically distinct species independent from O. nubilalis.     

Rare cell isolation using antibodies covalently linked to slides: application to fetal cells in maternal blood

We describe here a new type of method for isolation of rare cell populations in biological fluids. The method is based on the anthraquinone technology for covalent binding of molecules to a polymer surface. An anthraquinone molecule conjugated via a linker to an electrophilic group (AQ Immobilizer™ reagent, Exiqon A/S) is covalently bound to a polymer surface by UV irradiation. The electrophilic group of this AQ reagent can covalently bind a specific antibody directed against a specific cell marker. Applying a cell sample to the functional surface, the cells having the specific cell marker on the cell surface will bind to the antibody on the functional surface. Using this technique, even extremely small cell populations may be isolated. We succeeded in isolating fetal cells from maternal blood samples in the first trimester for chromosome defects genetic diagnosis. Copyright © 2003 John Wiley & Sons, Ltd.     

Pipeline leakage detection and isolation: An integrated approach of statistical and wavelet feature extraction with multi-layer perceptron neural network (MLPNN)

Leakage diagnosis of hydrocarbon pipelines can prevent environmental and financial losses. This work proposes a novel method that not only detects the occurrence of a leakage fault, but also suggests its location and severity. The OLGA software is employed to provide the pipeline inlet pressure and outlet flow rates as the training data for the Fault Detection and Isolation (FDI) system. The FDI system is comprised of a Multi-Layer Perceptron Neural Network (MLPNN) classifier with various feature extraction methods including the statistical techniques, wavelet transform, and a fusion of both methods. Once different leakage scenarios are considered and the preprocessing methods are done, the proposed FDI system is applied to a 20-km pipeline in southern Iran (Goldkari-Binak pipeline) and a promising severity and location detectability (a correct classification rate of 92%) and a low False Alarm Rate (FAR) were achieved.     

潞安矿区煤层渗透率的各向异性特征实验研究

为了研究原位煤体渗透性的各向异性特征,以山西潞安常村矿3号煤层圆柱试样为对象,利用TCQT-Ⅲ型低渗煤层气相驱替增产试验装置,对煤样进行加载,并以氮气注入压力2.0 MPa的条件下,分析垂直层理和平行层理2个方向的煤体变形和渗透率变化特征。实验结果表明:煤样在加载过程中,平行和垂直层理煤样渗透率均随着有效应力的增大而减小,平行层理方向的渗透率始终大于垂直层理方向,应力加载初期渗透率急剧下降,最后逐渐趋于平缓;径向应变的增加量与渗透率呈正相关性,且平行层理相关性大于垂直层理;沿平行层理方向的裂隙度大于沿垂直层理方向,沿垂直层理方向的应变量大于沿平行层理方向;应变增加量均随有效应力的增加而逐渐减小。研究结果可为煤层井网布置及优化提供参考。