Effects of biosurfactants on assays of PCB congeners in transgenic arabidopsis plants carrying a recombinant guinea pig AhR-mediated GUS reporter gene expression system

The transgenic Arabidopsis plants carrying a recombinant guinea pig (g) aryl hydrocarbon receptor (AhR)-mediated β-glucuronidase (GUS) reporter gene expression system were generated for assays of polychlorinated biphenyl (PCB) congeners. The selected transgenic Arabidopsis plant XgD2V11-6 exhibited a correlation between uptake of PCB126 and PCB126-induced GUS activity. Also, the plants showed induced GUS activity towards the supplemental indole 3-acetic acid (IAA). Thus, the GUS assay may reflect induction by both endogenous and exogenous AhR ligands. When biosurfactants, MEL-B, produced in the culture of yeast isolated from plants were used for assays of PCB congeners in the transgenic Arabidopsis plants, they showed marked PCB126 dose-dependent and toxic equivalency factor (TEF) dependent GUS activities. The effects of biosurfactants were clearer when the plants were cultivated on soils containing PCB congeners for 7 days as compared with on soils for 3 days as well as in the medium for 3 days. Therefore, it was estimated that biosurfactants form micellae with PCB congeners, which are easily uptaken by the plants in a mode of passive diffusion, transport into the aerial parts and then induce GUS activity.     

Predicting the particle size distribution of fine-grained and sandy soils using deep learning for classifying recovered soils separated from tsunami deposits

Journal of Material Cycles and Waste Management - Disaster wastes, particularly those generated in the tsunami, comprise soil and sediments, and recovered soil is yielded through treatment such as...     

Do we need to examine the quantitative data obtained from toxicity studies for both normality and homogeneity of variance?

Most of the statistical techniques used to evaluate the data obtained from toxicity studies are based on the assumption that the data show a normal distribution and homogeneity of variance. Literature review on toxicity studies on laboratory animals reveals that in most of the cases homogeneity of variance alone is examined for the data obtained from these studies. But the data that show homogeneity of variance need not always show a normal distribution. In fact, most of the data derived from toxicity studies, including hematological and biochemical parameters show a non-normal distribution. On examining normality of data obtained from various toxicity studies using different normality tests, we observed that Shapiro-Wilk test is more appropriate than Kolmogorov-Smimov test, Lilliefors test, the normal probability paper analysis and Chi square test. But there are situations, especially in the long-term toxicity studies, where normality is not shown by one or more than one of the dosage groups. In this situation, we propose that the data maybe analyzed using Dunnett multiple comparison test after excluding the data of the groups that do not show normality However, the biological relevance of the excluded data has to be carefully scrutinized. We also observed that the tendency of the data to show a normal distribution seems to be related to the age of the animals. Present paper describes various tests commonly used to test normality and their power, and also emphasizes the need of subjecting the data obtained from toxicity studies to both normality and homogeneity tests. A flow chart suggesting the statistical techniques that maybe used for both the types of data showing a normal or non-normal distribution is also proposed.     

Assays of polychlorinated biphenyl congeners and co-contaminated heavy metals in the transgenic Arabidopsis plants carrying the recombinant guinea pig aryl hydrocarbon receptor-mediated β-glucuronidase reporter gene expression system

The transgenic Arabidopsis plant XgD2V11-6 carrying the recombinant guinea pig (g) aryl hydrocarbon receptor (AhR)-mediated β-glucuronidase (GUS) reporter gene expression system was examined for assay of polychlorinated biphenyl (PCB) congeners and co-contaminated heavy metals. When the transgenic Arabidopsis plants were treated with PCB126 (toxic equivalency factor; TEF: 0.1) and PCB169 (TEF: 0.03), the GUS activity of the whole plants was increased significantly. After treatment with PCB80 (TEF: 0), the GUS activity was nearly the same level as that treated with 0.1% dimethylsulfoxide (DMSO) as a vehicle control. After exposure to a 1:1 mixture of PCB126 and PCB169, the GUS activity was increased additively. However, after exposure to a mixture of PCB126 and PCB80, the GUS activity was lower than that of the treatment with PCB126 alone. Thus, PCB80 seemed to be an antagonist towards AhR. When the transgenic plants were treated with each of the heavy metals Fe, Cu, Zn, Cd and Pb together with PCB126, Cd and Pb increased the PCB126-induced GUS activity. On the other hand, Fe, Cu and Zn did not affect the PCB126-induced GUS activity. In the presence of the biosurfactant mannosylerythritol lipid-B (MEL-B) and the carrier protein bovine serum albumin (BSA), the PCB126-induced GUS activity was increased, but the Cd-assisted PCB126-induced GUS activity was not affected. Thus, MEL-B and BSA seemed to increase uptake and transport of PCB126, respectively.     

Novel enzymatic activity of cell free extract from thermophilic Geobacillus sp. UZO 3 catalyzes reductive cleavage of diaryl ether bonds of 2,7-dichlorodibenzo-p-dioxin

We characterized the ability of the cell free extract from polychlorinated dibenzo-p-dioxins degrading bacterium Geobacillus sp. UZO 3 to reduce even highly chlorinated dibenzo-p-dioxins such as octachlorodibenzo-p-dioxins in incineration fly ash. The degradation of 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD) as a model dioxin catalyzed by the cell free extract from this strain implicates that the ether bonds of 2,7-DCDD molecule undergo reductive cleavage, since 4′,5-dichloro-2-hydroxydiphenyl ether and 4-chlorophenol were detected as intermediate products of 2,7-DCDD degradation.     

Female sex pheromone and male behavioral responses of the bombycid moth <Emphasis Type="Italic">Trilocha varians</Emphasis>: comparison with those of the domesticated silkmoth <Emphasis Type="Italic">Bombyx mori</Emphasis>

Analysis of female sex pheromone components and subsequent field trap experiments demonstrated that the bombycid moth Trilocha varians uses a mixture of (E,Z)-10,12-hexadecadienal (bombykal) and (E,Z)-10,12-hexadecadienyl acetate (bombykyl acetate) as a sex pheromone. Both of these components are derivatives of (E,Z)-10,12-hexadecadienol (bombykol), the sex pheromone of the domesticated silkmoth Bombyx mori. This finding prompted us to compare the antennal and behavioral responses of T. varians and B. mori to bombykol, bombykal, and bombykyl acetate in detail. The antennae of T. varians males responded to bombykal and bombykyl acetate but not to bombykol, and males were attracted only when lures contained both bombykal and bombykyl acetate. In contrast, the antennae of B. mori males responded to all the three components. Behavioral analysis showed that B. mori males responded to neither bombykal nor bombykyl acetate. Meanwhile, the wing fluttering response of B. mori males to bombykol was strongly inhibited by bombykal and bombykyl acetate, thereby indicating that bombykal and bombykyl acetate act as behavioral antagonists for B. mori males. T. varians would serve as a reference species for B. mori in future investigations into the molecular mechanisms underlying the evolution of sex pheromone communication systems in bombycid moths.     

Synergistic increase in cell lethality by dieldrin and H2O2 in rat thymocytes: Effect of dieldrin on the cells exposed to oxidative stress

Dieldrin, one of persistent pesticides, is highly resistant to biotic and abiotic degradation. It is accumulated in organisms. Recent studies suggest that dieldrin exerts a potent cytotoxic action on cells exposed to oxidative stress. In this study, the effect of dieldrin on rat thymocytes exposed to hydrogen peroxide (H₂O₂)-induced oxidative stress was examined. Dieldrin at 5 μM and H₂O₂ at 300 μM slightly increased cell lethality from a control value of 5.4 ± 0.5% (mean ± standard deviation of four experiments) to 7.8 ± 1.3% and 9.0 ± 0.3%, respectively. Simultaneous application of dieldrin and H₂O₂ significantly increased cell lethality to 46.2 ± 1.8%. The synergistic increase in cell lethality was dependent on dieldrin concentration (0.3–5 μM) but not on H₂O₂ concentration (30–300 μM). Dieldrin accelerated H₂O₂-induced cell death, which was estimated with the help of annexin V-FITC and propidium iodide. Presence of either dieldrin or H₂O₂ decreased the cellular content of nonprotein thiol and increased intracellular Zn²⁺ concentration. The combination of dieldrin and H₂O₂ further pronounced these effects. TPEN, a chelator of intracellular Zn²⁺, significantly attenuated the synergistic increase in cell lethality induced by dieldrin and H₂O₂. It is, therefore, suggested that dieldrin augments the cytotoxicity of H₂O₂ in a Zn²⁺-dependent manner.     

Interfaces in Cross-Linked and Grafted Bacterial Cellulose/Poly(Lactic Acid) Resin Composites

This article presents approaches to maximize the mechanical performance of bacterial cellulose/poly(lactic acid) composites through chemical modification of the interface. This is achieved by both cross-linking the layered bacterial cellulose structure and by grafting maleic anhydride to the matrix material. Unmodified and glyoxalized bacterial cellulose (BC) networks have been embedded in poly(lactic acid) (PLA) resin and then in maleated resin using a compression molding method. The effect of these chemical modifications on the physical properties of these composites is reported. The tensile properties of the composites showed that Young??s moduli can be increased significantly when both BC networks and PLA were chemically modified. Interface consolidation between layers in BC networks has been achieved by glyoxalization. The effect of these modifications on both stress-transfer between the fibers and between the matrix and the fibers was quantified using Raman spectroscopy. Two competitive deformation mechanisms are identified; namely the mobility between BC layers, and between BC and PLA. The coupling strength of these interfaces could play a key role for optimization of these composites?? mechanical properties.     

Effect of barley chromosome addition on the susceptibility of wheat to feeding by a gall-inducing leafhopper

The maize orange leafhopper Cicadulina bipunctata is distributed widely in tropical and subtropical regions of the Old World and feeds on various Poaceae. The leafhopper is recognized as an important pest of maize in several countries. Adults as well as nymphs of C. bipunctata induce growth stunting and galls characterized by the severe swelling of leaf veins on many cereal crops including wheat, rice, and maize, but do not on barley. To clarify the mechanism of growth stunting and gall induction by C. bipunctata, we used six barley chromosome disomic addition lines of wheat (2H–7H) and investigated the effect of barley (cv. Betzes) chromosome addition on the susceptibility of wheat (cv. Chinese Spring) to feeding by the leafhopper. Feeding by C. bipunctata significantly stunted the growth in 2H, 3H, 4H, and 5H, but did not in 6H and 7H. The degree of gall induction was significantly weaker and severer in 3H and 5H than in Chinese Spring, respectively. These results suggest that barley genes resistant to growth stunting and gall induction exist in 6H and 7H, and 3H, respectively. 5H is considered to be useful for future assays investigating the mechanism of gall induction by this leafhopper because of the high susceptibility to the feeding by C. bipunctata. Significant correlation between the degrees of growth stunting and gall induction was not detected in the six chromosome addition lines and Chinese spring. This implies that these two symptoms are independent phenomena although both are initiated by the feeding of C. bipunctata.