Project description:Like vertebrate animals, some invertebrates have been shown to exhibit fear- or anxiety-like behavior while in apparatus that allow choice between sheltered, darkened spaces and open, lit spaces. The behavioral mechanisms by which invertebrates accomplish this behavior, and whether those mechanisms are similar across species, has not been fully studied. Across three experiments, we investigated possible behaviors that Great Ramshorn snails (Planorbarius corneus) could use to accomplish fear behavior while in presence of the odor of a predatory fish. In experiment one, we used a light/dark preference box to demonstrate reduced preference for exposed and lit areas caused by the predator odor. In experiment two, we used an open field apparatus to demonstrate an increase in refuge-seeking (thigmotaxis, or time spent near a wall) in diffusely lit but not dark environments caused by predator odor. In the same experiment we found the snails were photokinetic (they moved faster in the light than in the dark) but we saw no effect of predator odor on photokinesis. In experiment three, we conducted a second open field study with a directional light source and found no evidence of phototaxis (movement direction with respect to light), and no effect of predator odor on phototaxis. Thus, in our studies we found evidence for refuge-seeking as a mechanism for fear-like behavior in the presence of predator odor and little evidence for perhaps more computationally simple strategies of increased photokinesis and phototaxis.
| S-EPMC11623786 | biostudies-literature
Project description:Analysis of Planorbarius corneus hemocytes transcriptome during the infection with Bilharziella polonica
Project description:The erythrocruorin from the snail Planorbis corneus had a sedimentation coefficient, so/20,w, of 33.5 +/- 0.31 S, and a molecular weight of 1.65 x 10(6) +/- 0.04 x 10(6) by high-speed sedimentation-equilibrium ultracentrifugation. The amino acid composition and absorption spectrum of the protein are reported. A very low number of half-cystine residues was found, corresponding to 0.4 residue per haem group. The haem content was 2.76 +/- 0.22%, corresponding to a protein molecular weight of about 22300. Under both acid and alkaline conditions partial dissociation took place to yield mixtures of products that could not be identified. A subunit corresponding to that containing one haem group was not obtained under any of the dossociating conditions tried. Electron microscopy revealed a ring-shaped molecule about 12.2 +/- 0.5 nm in diameter. The native erythrocruorin bound O2 co-operatively, the intermediate value of h in Hill plots having values between 1.7 and 3.4 depending on the conditions.
Project description:Chromatin replication requires tight coordination of nucleosome assembly machinery with DNA replication machinery. While significant progress has been made in characterizing histone chaperones in this process, the mechanism of whereby nucleosome assembly couples with DNA replication remains largely unknown. Here we show that replication protein A (RPA), a single-stranded DNA (ssDNA) binding protein that is essential for DNA replication provides a binding platform for H3-H4 deposition by histone chaperons and is required for nucleosome formation on nascent chromatin. RPA binds free histone H3-H4 but not nucleosomal histones, and a RPA coated ssDNA stimulates assembly of H3-H4 onto double strand DNA in vitro. RPA mutant with reduced H3-H4 binding exhibits synthetic genetic interaction with mutations at key factors involved in replication-coupled (RC) nucleosome assembly, and are defective in assembly of replicating DNA into nucleosomes in cells. These results reveal a novel function for RPA in nucleosome assembly and a mechanism whereby nucleosome assembly is coordinated with DNA replication.
Project description:Porcine 60K BeadChip genotyping arrays (Illumina) are increasingly being applied in pig genomics to validate SNPs identified by re-sequencing or assembly-versus-assembly method. Here we report that more than 98% SNPs identified from the porcine 60K BeadChip genotyping array (Illumina) were consistent with the SNPs identified from the assembly-based method. This result demonstrates that whole-genome de novo assembly is a reliable approach to deriving accurate maps of SNPs.