Transcriptomic response of wolf spider, Pardosa pseudoannulata, to transgenic rice expressing Bacillus thuringiensis Cry1Ab protein.

BACKGROUND: Bacillum thuringiensis (Bt) toxin produced in Cry1-expressing genetically modified rice (Bt rice) is highly effective to control lepidopteran pests, which reduces the needs for synthetic insecticides. Non-target organisms can be exposed to Bt toxins through direct feeding or trophic interactions in the field. The wolf spider Pardosa pseudoannulata, one of the dominant predators in South China, plays a crucial role in the rice agroecosystem. In this study, we investigated transcriptome responses of the 5th instar spiders fed on preys maintained on Bt- and non-Bt rice. RESULTS: Comparative transcriptome analysis resulted in 136 differentially expressed genes (DEGs) between spiderlings preying upon N. lugens fed on Bt- and non-Bt rice (Bt- and non-Bt spiderlings). Functional analysis indicated a potential impact of Bt toxin on the formation of new cuticles during molting. GO and KEGG enrichment analyses suggested that GO terms associated with chitin or cuticle, including "chitin binding", "chitin metabolic process", "chitin synthase activity", "cuticle chitin biosynthetic process", "cuticle hydrocarbon biosynthetic process", and "structural constituent of cuticle", and an array of amino acid metabolic pathways, including "alanine, asparatate and glutamate metabolism", "glycine, serine and theronine metabolism", "cysteine and methionine metabolism", "tyrosine metabolism", "phenylalanine metabolism and phenylalanine", and "tyrosine and tryptophan biosynthesis" were significantly influenced in response to Cry1Ab. CONCLUSIONS: The Cry1Ab may have a negative impact on the formation of new cuticles during molting, which is contributed to the delayed development of spiderlings. To validate these transcriptomic responses, further examination at the translational level will be warranted.

Altered Expression of EPO Might Underlie Hepatic Hemangiomas in LRRK2 Knockout Mice.

Parkinson's disease (PD) is a severe neurodegenerative disorder caused by progressive loss of dopaminergic neurons in the substantia nigra pars compacta of the midbrain. The molecular mechanism of PD pathogenesis is unclear. Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are a common genetic cause of familial and sporadic PD. However, studies on LRRK2 mutant mice revealed no visible dopaminergic neuronal loss in the midbrain. While surveying a LRRK2 knockout mouse strain, we found that old animals developed age-dependent hepatic vascular growths similar to cavernous hemangiomas. In livers of these hemangioma-positive LRRK2 knockout mice, we detected an increased expression of the HIF-2α protein and significant reactivation of the expression of the HIF-2α target gene erythropoietin (EPO), a finding consistent with a role of the HIF-2α pathway in blood vessel vascularization. We also found that the kidney EPO expression was reduced to 20% of the wild-type level in 18-month-old LRRK2 knockout mice. Unexpectedly, this reduction was restored to wild-type levels when the knockout mice were 22 months to 23 months old, implying a feedback mechanism regulating kidney EPO expression. Our findings reveal a novel function of LRRK2 in regulating EPO expression and imply a potentially novel relationship between PD genes and hematopoiesis.

Bioaccumulation of Cry1Ab protein from an herbivore reduces anti-oxidant enzyme activities in two spider species.

Cry proteins are expressed in rice lines for lepidopteran pest control. These proteins can be transferred from transgenic rice plants to non-target arthropods, including planthoppers and then to a predatory spider. Movement of Cry proteins through food webs may reduce fitness of non-target arthropods, although recent publications indicated no serious changes in non-target populations. Nonetheless, Cry protein intoxication influences gene expression in Cry-sensitive insects. We posed the hypothesis that Cry protein intoxication influences enzyme activities in spiders acting in tri-trophic food webs. Here we report on the outcomes of experiments designed to test our hypothesis with two spider species. We demonstrated that the movement of CryAb protein from Drosophila culture medium into fruit flies maintained on the CryAb containing medium and from the flies to the spiders Ummeliata insecticeps and Pardosa pseudoannulata. We also show that the activities of three key metabolic enzymes, acetylcholine esterase (AchE), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) were significantly influenced in the spiders after feeding on Cry1Ab-containing fruit flies. We infer from these data that Cry proteins originating in transgenic crops impacts non-target arthropods at the physiological and biochemical levels, which may be one mechanism of Cry protein-related reductions in fitness of non-target beneficial predators.