Biology subjects

Scheel, D.

Publications and source records attributed to Scheel, D..

3 recordsLinked to original sources

bioRxiv2024

Octopus can use odor plumes to find food

Odor-plume-guided navigation, tracking an odor plume to its source, is a primordial behavior used by most animals to search beyond the visual range. Here we report the first laboratory observations of octopuses performing this behavior, demonstrating that they can use odor plumes to find food. In a three-station discrimination task carried out in the dark, octopus showed a strong preference to move upstream towards the food-baited target, supporting the hypothesis that they are performing odor-guided search. When seeking a single baited target, also in the dark, octopuses not only preferred to move upstream towards the food source, but they also displayed characteristic motions associated with odor-gated rheotaxis, a commonly used odor tracking strategy used by many animals, which includes pausing, switchbacks, and across-stream redirections to the bait. Additionally, when approaching single baited stations the octopus often made reactive fast lunging motions. The observation of these fast arm-aligned motions (FAAM), taken together with the observation that the octopus did not have a characteristic body axis orientation to the bait, as would be expected if bilaterally symmetric organs such as the olfactory pits guided this behavior, supports the hypothesis that the suckers are the primary chemosensory organs driving octopus odor-guided behaviors.

animal behavior and cognition↗

bioRxiv2021

In the Line of Fire: Debris Throwing by Wild Octopuses

Wild octopuses at an Australian site frequently propel shells, silt, and algae through the water by releasing these materials from their arms while creating a forceful jet from the siphon held under the arm web. These "throws" occur in several contexts, including interactions with conspecifics, and material thrown in conspecific contexts frequently hits other octopuses. Some throws appear to be targeted on other individuals and play a social role, as suggested by several kinds of evidence. Such throws were significantly more vigorous and more often used silt, rather than shells or algae, and high vigor throws were significantly more often accompanied by uniform or dark body patterns. Some throws were directed differently from beneath the arms and such throws were significantly more likely to hit other octopuses. Throws targeted at other individuals in the same population, as these appear to be, are the least common form of nonhuman throwing.

animal behavior and cognition↗

bioRxiv2019

Phosphorylation of the CAMTA3 transcription factor triggers its destabilization and nuclear export.

The calmodulin-binding transcription activator 3 (CAMTA3) is a repressor of immunity-related genes but an activator of cold-induced genes in plants. Post-transcriptional or -translational mechanisms have been proposed to control CAMTA3s role in the crosstalk between immune and chilling responses. Here, we show that treatment with the bacterial flg22 elicitor, but not cold stress, induces a phospho-mobility shift of CAMTA3 proteins. Correspondingly, CAMTA3 is directly phosphorylated by two flg22-responsive mitogen-activated protein kinases (MAPKs), MPK3 and MPK6, which triggers CAMTA3 nuclear export and destabilization. SR1IP1, a substrate E3 ubiquitin ligase adaptor required for pathogen-induced CAMTA3 degradation, is shown here to be likely plasma-membrane-localized and therefore cannot physically interact with the nuclear CAMTA3. Despite the flg22-inducible re-localization of CAMTA3 to the cytoplasm, we failed to detect CAMTA3-SR1IP1 complexes. Hence, the role of SR1IP1 for CAMTA3 degradation needs to be re-evaluated. Surprisingly, flg22 elicitation can still induce nuclear export and phospho-mobility shift of a phospho-null CAMTA3 that cannot be phosphorylated by MAPKs, suggesting the participation of additional flg22-responsive kinase(s). A constitutively-active calcium-dependent protein kinase, CPK5, can stimulate a phospho-mobility shift in CAMTA3 similar to that induced by flg22. Although CPK5 can interact with CAMTA3, it did not directly phosphorylate CAMTA3, suggesting the requirement of a still unidentified downstream kinase or additional components. Overall, at least two flg22-responsive kinase pathways target CAMTA3 to induce degradation that presumably serves to remove CAMTA3 from target promoters and de-repress expression of defence genes.\n\nOne sentence summaryTreatment with flg22 activates two independent kinase pathways that effect CAMTA3 phosphorylation and degradation.

plant biology↗