3 Papers found (0.008 seconds)

Anderson H Tan et al. (2005) International Worm Meeting "Optimization of bioassay systems on plants expressing crystal toxin for the control of plant parasitic nematodes"

Raffi Aroian, Anderson H Tan, Xiang-qian Li

[

International Worm Meeting,

2005]

Every year, plant parasitic nematodes cause over $100 billion in damages due to crop loss and plant damage. Chemical pesticides are the most widespread form of PPN control, but with the prohibition of methyl bromide other approaches to control are necessary. One approach under consideration is Bacillus thuringiensis Bt Crystal (Cry) proteins. Crystal proteins produced by Bt have been commonly used for biocontrol of insects. Our lab has demonstrated that some Bt Cry proteins kill free-living nematodes and the free-living stages of one animal parasitic nematode (Nippostrongylus brasiliensis). These results then set the stage for testing whether Cry proteins can control plant-parasitic nematodes.Since most plant parasitic nematodes are obligate endoparasites that feed and develop inside the plant root, delivering Bt Cry protein requires the proteins be expressed directly in the plant. The Cry proteins would then transferred to the nematode through feeding.Our goal is to establish a reliable system for testing transgenic roots for control of endoparasitic nematodes. This involves expressing the proteins in an appropriate plant and/or root system, infecting those roots with an appropriate nematode host, and then quantitating various parameters of infection. We have synthesized plant-friendly versions of two of these toxins, Cry 6A and Cry 5B. These were transformed in tomato roots using Agrobacterum rhizogenes(hairy roots) and into Arabidopsis using A. tumefaciens. These plant systems are both candidates for infection by root-knot nematode, Meloidogyne incognita.We tested different growth media, lighting conditions, and inoculum levels, in order to optimize number of infections and to develop a reliable system to test the effect of Cry toxins on M. incognita. The experimental conditions and results will be presented.

Catalano, Federico et al. (2021) International Worm Meeting "Characterization of a new model of Wilson disease to find innovative targets and pathways to attenuate Cu toxicity"

Santonicola, Pamela, Zampi, Giuseppina, Puchkova, Ludmila, Di Schiavi, Elia, Ilicheva, Ekaterina, Orlov, Iurii, Polishchuk, Roman, Polishchuk, Elena, Catalano, Federico

[

International Worm Meeting,

2021]

Copper is an essential nutrient that is required for many vitally important processes, such as respiration, connective tissue biogenesis and iron metabolism. However, excess of copper represents a serious danger, due to its ability to induce free radical-induced oxidative damage, as well as impairments of lipid metabolism and neuronal activity. Wilson disease (WD) represents an excellent system for Cu toxicity studies. WD is caused by mutations in ATP7B pump effluxing excess Cu from hepatocytes into the bile. Loss of ATP7B leads to toxic Cu overload in liver and then in brain, causing fatal hepatic and neurologic abnormalities. Over the last years, C. elegans has emerged as an easy-to-use and highly responsive model of micronutrient metabolism. For this reason, we have generated and characterized a new C. elegans model of WD. CUA-1, the C. elegans ortholog of ATP7B, resides in lysosome-like organelles to sequester excess of copper and, therefore, represents a key component regulating copper supply and detoxification in order to maintain copper homeostasis. Using Crispr-Cas9 technology a cua-1(knu781 [H828Q]) strain was generated, that carries a substitution in conserved histidine corresponding to the most common H1069Q variant of ATP7B causing WD in European and North American population. In order to understand the effect of H828Q mutation on C. elegans phenotype we employed several assays that allow life span, motility, egg laying, larval development and mitochondria damage to be evaluated. Moreover, we are studying the colocalization of the mutant CUA-1 protein with markers of different organelles, such as lysosome, Golgi and ER, as well as with the copper sensor CF4. Our studies established that in absence of copper, cua-1(knu781) does not show any significant phenotypic aberrations. However, mutant worms exhibited very poor resistance to copper compared to the control strain. This manifested in a strong decrease in number of eggs, a delay in the larval development, a shorter lifespan, impaired motility and mitochondrial damage. Taken together our finding suggest that cua-1(knu781) represents an excellent model for Cu toxicity studies in WD. We further plan to use this model for identification and validation of the new therapeutic targets for WD. Moreover, cua-1(knu781) will be used for evaluation of the FDA-approved drugs that emerged from a high throughput screening for compounds reducing Cu toxicity in WD.

Alexander G. Eberhardt et al. (2007) International Worm Meeting "Sexual reproduction in the free-living generation of the parasitic nematode Strongyloides papillosus."

Werner E. Mayer, Adrian Streit, Linda Nemetschke, Alexander G. Eberhardt

[

International Worm Meeting,

2007]

The nematode genus Strongyloides consists of parasites that live as parthenogenetic females in the small intestines of their hosts. In addition to producing parasitic offspring, they can also form a facultative free-living generation with males and females. In most Strongyloides species the progeny of these free-living adults is uniformously female and infective. Based on cytological observations in multiple species several authors1,2,3 have proposed that males do not contribute genetically to the progeny of the free-living generation but that the sperm is merely required to induce parthenogenetic development of the oocyte (pseudogamy). In contrast to these findings, Viney and colleagues4 have found that genetic markers can be passed on to the next generation in S. ratti. We are analyzing the mode of reproduction of the free-living generation of S. papillosus, a parasite of ruminants, cytologically and genetically. We have shown that also in S. papillosus males do contribute genetic material to the next generation5. While some genetic markers are inherited in a manner that is consistent with standard, mendelian, autosomal inheritance, others behave differently in that heterozygous males pass on preferentially or exclusively only one of their two alleles. We are currently testing the hypothesis that this is the consequence of the particular mode of sex determination in S. papillosus. In contrast to most other Strongyloides species that employ an XX/XO sex determining system, in S. papillosus males have a chromosome pair where one of the homologous chromosomes is intact and the other one lacks a large portion as the result of a sex specific chromatin diminution event6. In the process of our work we have noticed that the taxon S. papillosus, most probably, does not reflect a true biological species, but comprises of at least two relatively closely related but reproductively isolated species that can occur as mixed infections in the same host individual. We are currently analyzing the distribution of these two species in local sheep and cattle populations. 1Nigon, V., Roman, E., 1952 Bull biol Fr Belg 86:404-448. 2Bolla, R.I., Roberts, L.S., 1968 J Parasitol 54:849-855. 3Triantaphyllou, A.C., Moncol, D.J., 1977 J Parasitol 63:961-973. 4Viney, M.E., Matthews, B.E., Walliker, D., 1993 Proc R Soc Lond B Biol Sci 254:213-219. 5Eberhardt, A.G., Mayer, W.E., Streit, A., 2007 Int J Parasitol., in press. 6Albertson, D.G., Nwaorgu, O.C., Sulston, J.E., 1979 Chromosoma 75, 75-87.