Predation threats for a 24-h period activated the extension of axons in the brains of Xenopus tadpoles

Abstract

The threat of predation is a driving force in the evolution of animals. We have previously reported that Xenopus laevis enhanced their tail muscles and increased their swimming speeds in the presence of Japanese larval salamander predators. Herein, we investigated the induced gene expression changes in the brains of tadpoles under the threat of predation using 3′-tag digital gene expression profiling. We found that many muscle genes were expressed after 24 h of exposure to predation. Ingenuity pathway analysis further showed that after 24 h of a predation threat, various signal transduction genes were stimulated, such as those affecting the actin cytoskeleton and CREB pathways, and that these might increase microtubule dynamics, axonogenesis, cognition, and memory. To verify the increase in microtubule dynamics, DiI was inserted through the tadpole nostrils. Extension of the axons was clearly observed from the nostril to the diencephalon and was significantly increased (P ≤ 0.0001) after 24 h of exposure to predation, compared with that of the control. The dynamic changes in the signal transductions appeared to bring about new connections in the neural networks, as suggested by the microtubule dynamics. These connections may result in improved memory and cognition abilities, and subsequently increase survivability.

Novel approach to enhance sensitivity while retaining morphology in fragile tissue sections for mass spectrometry imaging

“…We could find the olfactory bulb, eye, otolith, muscle, and brain on the slides. Identified portions of the brain of the tadpoles include the telencephalon, diencephalon, mesencephalon, and metencephalon, 14 each of which was only 1 or 2 mm in size and difficult to recognize in the Normal sections. In contrast, detailed morphological information about these structures was visualized in the Film and Transfer sections.…”

“…We investigated metabolite dynamics in the tadpoles under stress predation 11,14 and metamorphosis. We previously attempted to determine the distribution of thyroid hormone metabolites on Film sections, 8 but small amounts of metabolites were difficult to localize.…”

Identification and validation of an autophagy-related signature for predicting survival in lower-grade glioma

“…EEF2 (Eukaryotic elongation factor 2) is a well-studied gene that plays a key role in protein synthesis by mediating the translocation step in peptide chain elongation [ 49 ]. In addition, the associated protein EEF2 is considered a tumor-associated antigen that is upregulated in most types of cancers and that plays a tumorigenic role in the growth of cancer cells [ 50 ].…”

A novel ND1 mitochondrial DNA mutation is maternally inherited in growth hormone transgenesis in amago salmon (Oncorhynchus masou ishikawae)

“…The IPA protocol has been previously described in detail 54 and is described in the “ Supplementary Methods ”. In addition, the relationships between phenotype and NADPH oxidase were predicted as previously described 18 .…”