No abstract

Microtubules (MTs) are important structures of the cytoskeleton in neurons. Mammalian brain MTs act as biomolecular transistors that generate highly synchronous electrical oscillations. However, their role in brain function is largely unknown. To gain insight into the MT electrical oscillatory activity of the brain, we turned to the honeybee (Apis mellifera) as a useful model to isolate brains and MTs. The patch clamp technique was applied to MT sheets of purified honeybee brain MTs. High resistance seal patches showed electrical oscillations that linearly depended on the holding potential between ± 200 mV and had an average conductance in the order of ~9 nS. To place these oscillations in the context of the brain, we also explored local field potential (LFP) recordings from the Triton X-permeabilized whole honeybee brain unmasking spontaneous oscillations after but not before tissue permeabilization. Frequency domain spectral analysis of time records indicated at least two major peaks at approximately ~38 Hz and ~93 Hz in both preparations. The present data provide evidence that MT electrical oscillations are a novel signaling mechanism implicated in brain wave activity observed in the insect brain.

The influence of high‐pressure homogenisation (HPH) at 100 MPa on Lacticaseibacillus paracasei 90 (L90) was studied in vitro and in situ (fermented milk and cheese). Lysis and injury signs were observed in cells treated with HPH, which were linked to the release of intracellular enzymes and changes in the metabolic activity of L90. HPH treatment led to a higher lactic acid content and lower pH and pyruvic acid levels in fermented milk. The microbiological and peptide profiles of cheeses were modified by using cells or cell‐free extracts of L90. Finally, this study suggests that L90 could release bioactive peptides.