Nematoda: Susceptibility of the egg to Bacillus thuringiensis toxins

Bottjer, Kurt P.; Bone, Leon W.; Gill, Sarjeet S.

doi:10.1016/0014-4894(85)90027-x

Cited by 47 publications

(13 citation statements)

References 5 publications

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“…Some bacteria (e.g. Bacillus sphaericus and B. thuringiensis) produce a toxin that kills nematode eggs in a dose-dependent manner (Bone et al, 1987;Bottjer et al, 1985). Similar patterns have been reported for an alga (Caulerpa taxifolia) and adult toads (Christensen, 1980;Bartoli and Boudouresque, 1997).…”

Section: Physical and Chemical Interferencesupporting

confidence: 61%

Diversity, decoys and the dilution effect: how ecological communities affect disease risk

Johnson

Thieltges

2010

Journal of Experimental Biology

290

264

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SUMMARY Growing interest in ecology has recently focused on the hypothesis that community diversity can mediate infection levels and disease (‘dilution effect’). In turn, biodiversity loss — a widespread consequence of environmental change — can indirectly promote increases in disease, including those of medical and veterinary importance. While this work has focused primarily on correlational studies involving vector-borne microparasite diseases (e.g. Lyme disease, West Nile virus), we argue that parasites with complex life cycles (e.g. helminths, protists, myxosporeans and many fungi) offer an excellent additional model in which to experimentally address mechanistic questions underlying the dilution effect. Here, we unite recent ecological research on the dilution effect in microparasites with decades of parasitological research on the decoy effect in macroparasites to explore key questions surrounding the relationship between community structure and disease. We find consistent evidence that community diversity significantly alters parasite transmission and pathology under laboratory as well as natural conditions. Empirical examples and simple transmission models highlight the diversity of mechanisms through which such changes occur, typically involving predators, parasite decoys, low competency hosts or other parasites. However, the degree of transmission reduction varies among diluting species, parasite stage, and across spatial scales, challenging efforts to make quantitative, taxon-specific predictions about disease. Taken together, this synthesis highlights the broad link between community structure and disease while underscoring the importance of mitigating ongoing changes in biological communities owing to species introductions and extirpations.

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Section: Physical and Chemical Interferencesupporting

confidence: 61%

Diversity, decoys and the dilution effect: how ecological communities affect disease risk

Johnson

Thieltges

2010

Journal of Experimental Biology

290

264

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“…israelensis and ssp. kurstaki on eggs and nematode juveniles (Bottjer et al, 1985;Meadows and Bone, 1990). Our observation that nematode numbers were reduced across all three sites, and that the nematode communities were distinctly different in each site suggests that the effect is generic and not limited to particular nematode groups.…”

Section: Discussionmentioning

confidence: 69%

A Comparison of Soil Microbial Community Structure, Protozoa and Nematodes in Field Plots of Conventional and Genetically Modified Maize Expressing the Bacillus thuringiens is CryIAb Toxin

Griffiths¹,

Caul²,

Thompson³

et al. 2005

Plant Soil

113

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Field trials were established at three European sites (Denmark, Eastern France, South-West France) of genetically modified maize (Zea mays L.) expressing the CryIAb Bacillus thuringiensis toxin (Bt), the nearisogenic non-Bt cultivar, another conventional maize cultivar and grass. Soil from Denmark was sampled at sowing (May) and harvest (October) over two years (2002, 2003); from E France at harvest 2002, sowing and harvest 2003; and from SW France at sowing and harvest 2003. Samples were analysed for microbial community structure (2003 samples only) by community-level physiological-profiling (CLPP) and phospholipid fatty acid analysis (PLFA), and protozoa and nematodes in all samples. Individual differences within a site resulted from: greater nematode numbers under grass than maize on three occasions; different nematode populations under the conventional maize cultivars once; and two occasions when there was a reduced protozoan population under Bt maize compared to non-Bt maize. Microbial community structure within the sites only varied with grass compared to maize, with one occurrence of CLPP varying between maize cultivars (Bt versus a conventional cultivar). An overall comparison of Bt versus non-Bt maize across all three sites only revealed differences for nematodes, with a smaller population under the Bt maize. Nematode community structure was different at each site and the Bt effect was not confined to specific nematode taxa. The effect of the Bt maize was small and within the normal variation expected in these agricultural systems.

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“…Smith and Couché (1991) hypothesized that the bacterium is a natural component of the phylloplane microflora that has evolved in a symbiotic or mutualistic association with plants to provide protection against herbivores. Addison (1993) suggested that B. thuringiensis protein production might have evolved as a defense against invertebrates feeding on bacteria or potential microbial competitors in soil and he presented evidence that several groups of taxa with representatives in the soil fauna, such as earthworms (Smirnoff and Heimpel 1961;Atlavinyté et al1982), nematodes (Bottjer et al 1985;Meadows et al 1990) and mites (Oatman 1965;Chapman and Hoy 1991), are indeed susceptible to B. thuringiensis. Many of these studies focused on organisms of economic importance.…”

Section: Introductionmentioning

confidence: 98%

Field decomposition of transgenic Bt maize residue and the impact on non-target soil invertebrates

2007

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Genetically modified Bacillus thuringiensis Berliner (Bt) maize (Zea mays L.) expressing Cry toxins against various target pests is now grown on more than 16 million hectares worldwide, but its potential effects on the soil ecosystem need to be further investigated. In an 8-month field study, we investigated the effects of Bt maize expressing the Cry1Ab protein on both the soil community and maize residue decomposition. We used litterbags with three different mesh sizes (20, 125, and 5,000 μm) to investigate potential effects of different soil organism groups on the decomposition processes. Litterbags were incorporated into the soil in fall into a field that had previously been planted with non-Bt maize and subsamples were removed monthly. The dry weight of the remaining residue was measured for all bags. Bt and non-Bt maize decomposed similarly in large mesh bags, which allowed the whole soil organism community to enter and interact with each other. In contrast, Bt maize decomposed significantly faster than non-Bt maize at some sample dates in winter in bags with small and medium mesh sizes. At the end of the experiment in late spring, however, there was no significant difference in the amount of maize plant residues remaining for any of these three mesh sizes. Additionally, soil organisms from bags with the largest mesh size were identified. The most frequent taxa extracted were collembolans (Isotomidae, Tullbergiidae, Entomobryidae), mites (Gamasina, Oribatida), and annelids (Enchytraeidae). Three of these taxa were extracted in higher numbers from non-Bt than Bt residue (Tullbergiidae, Gamasina, Enchytraeidae), while there was no difference in the number of individuals extracted for the remaining three taxa. Our results do not show major changes in the decomposition of Bt maize residue and in the composition of the soil organism community. However, further studies are needed that assess the impact of the continuous release of Cry1Ab via root exudates and plant biomass on the soil ecosystem.

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Nematoda: Susceptibility of the egg to Bacillus thuringiensis toxins

Cited by 47 publications

References 5 publications

Diversity, decoys and the dilution effect: how ecological communities affect disease risk

Diversity, decoys and the dilution effect: how ecological communities affect disease risk

A Comparison of Soil Microbial Community Structure, Protozoa and Nematodes in Field Plots of Conventional and Genetically Modified Maize Expressing the Bacillus thuringiens is CryIAb Toxin

Field decomposition of transgenic Bt maize residue and the impact on non-target soil invertebrates

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