Biology subjects

Clemens, H.

Publications and source records attributed to Clemens, H..

2 recordsLinked to original sources

bioRxiv2026

Isolation of thermophilic plastic-degrading bacteria from hot springs of Aotearoa-New Zealand

Geothermal springs are unique environments that harbor diverse populations of microorganisms. As a result of their environmental and geochemical variability, different springs can support distinct heterogeneous communities of organisms with unique functional adaptations and metabolic capabilities. A recent molecular survey of Aotearoa-New Zealand hot springs indicated that these springs may support thermophilic microorganisms be able to degrade plastics. To test this, we applied a cultivation-centered approach via an in situ enrichment of putative plastic-degraders using high surface are polyethylene terephthalate (PET), polylactic acid (PLA), and polyhydroxybutyrate (PHB) substrates in a diversity of New Zealand hot springs. The plastic associated microbial communities were characterized via marker gene and analyses. Finally, plastic-associated biofilms were used as inoculum to isolate thermophilic plastic degraders. Via this process, we confirm that there are plastic degrading bacteria are present in springs across Aotearoa-New Zealand. Moreover, we isolated two PHB degrading strains (Cuprividus sp. and Rubrobacter sp.) and demonstrated their capability to metabolize plastic under thermophilic conditions in vitro. While the pathways identified in our plastic degrading isolates suggest they may be able to metabolize plastics for carbon, the primary use of plastics by geothermal microbial communities does not appear to be as an energy source. Instead, they appear to mainly serve as surfaces for microbial attachment, composed primarily of non-plastic degrading taxa.

microbiology↗

bioRxiv2021

Value-based decision-making between affective memories

Affective biases can influence how past events are recalled from memory. However, the mechanisms underlying how discrete affective events shape memory formation and subsequent recall are not well understood. Further understanding this is important given the central role of negative biases in affective memory recall in depression and antidepressant drug action. In order to capture cognitive processes associated with affective memory formation and recall, we studied value-based decision-making between affective memories in two within-subject experiments (n=45 and n=74). Our findings suggest that discrete affective events, created by large magnitude Wheel of Fortune (WoF) outcomes, influence affective memory formation processes during reinforcement-learning (RL). After 24 hours, we show that healthy volunteers display stable preferences during value-based recall of affective memories in a binary decision-making task. Computational modelling of these preferences demonstrated a positive bias during value-based recall, induced by previously winning in the WoF. We further showed that value-based decision-making between affective memories engages the pupil-linked central arousal systems, leading to pupil constriction prior to, and differential pupil dilation after the decision onset depending on the valence of the chosen options. Taken together, we demonstrate that mechanisms underlying human affective memory systems can be described by RL and probability weighting models. This approach could be used as a translational assay to study the effects of novel antidepressants.

neuroscience↗