C. elegans PEZO-1 is a mechanosensitive ion channel involved in food sensation

PIEZO channels are force sensors essential for physiological processes, including baroreception and proprioception. The Caenorhabditis elegans genome encodes an orthologue gene of the Piezo family, pezo-1, which is expressed in several tissues, including the pharynx. This myogenic pump is an essential component of the C. elegans alimentary canal, whose contraction and relaxation are modulated by mechanical stimulation elicited by food content. Whether pezo-1 encodes a mechanosensitive ion channel and contributes to pharyngeal function remains unknown. Here, we leverage genome editing, genetics, microfluidics, and electropharyngeogram recording to establish that pezo-1 is expressed in the pharynx, including in a proprioceptive-like neuron, and regulates pharyngeal function. Knockout (KO) and gain-of-function (GOF) mutants reveal that pezo-1 is involved in fine-tuning pharyngeal pumping frequency, as well as sensing osmolarity and food mechanical properties. Using pressure-clamp experiments in primary C. elegans embryo cultures, we determine that pezo-1 KO cells do not display mechanosensitive currents, whereas cells expressing wild-type or GOF PEZO-1 exhibit mechanosensitivity. Moreover, infecting the Spodoptera frugiperda cell line with a baculovirus containing the G-isoform of pezo-1 (among the longest isoforms) demonstrates that pezo-1 encodes a mechanosensitive channel. Our findings reveal that pezo-1 is a mechanosensitive ion channel that regulates food sensation in worms.

C. elegans PEZO-1 is a Mechanosensitive Channel Involved in Food Sensation

PIEZO channels are force sensors essential for physiological processes including baroreception and proprioception. The Caenorhabditis elegans genome encodes an ortholog gene of the Piezo family, pezo-1, expressed in several tissues including the pharynx. This myogenic pump is an essential component of the C. elegans alimentary canal whose contraction and relaxation are modulated by mechanical stimulation elicited by food content. Whether pezo-1 encodes a mechanosensitive channel and contributes to pharyngeal function remains unknown. Here, we leverage genome editing, genetics, microfluidics, and electropharyngeogram recordings to establish that pezo-1 is expressed in the pharynx, including a proprioceptive-like neuron, and regulates pharyngeal function. Knockout (KO) and gain-of-function (GOF) mutants reveal that pezo-1 is involved in fine-tuning pharyngeal pumping frequency, sensing osmolarity, and food quality. Using pressure-clamp experiments in primary C. elegans embryo cultures, we determine that pezo-1 KO cells do not display mechanosensitive currents, whereas cells expressing wild-type or GOF PEZO-1 exhibit mechanosensitivity. Moreover, infecting the Spodoptera frugiperda cell line with a baculovirus containing the pezo-1 isoform G (among the longest isoforms) demonstrates that pezo-1 encodes a mechanosensitive channel. Our findings reveal that pezo-1 is a mechanosensitive ion channel that regulates food sensation in worms.

Screening of Secondary Metabolites Produced by Streptomyces Species from a Soil Sample that Can Produce Anti-Nematodal and Antiprotozoal Avermectins

Avermectins are a group of secondary metabolites produced by Streptomyces avermitilis, which act on invertebrates. They activate glutamate-gated chloride channels in their nerves and muscles which in turn disrupt pharyngeal function and locomotion. Avermectin ingested insects are paralyzed and starve to death. Ten isolates identified as avermectin producers were characterized by morphological, colony characters and biochemical tests. Secondary screening leads to the identification of four isolates PM2; PM4; PM7 and PM10 which produced 10, 8.4, 3.8 and 6.9mg respectively as identified by HPTLC. Bio-autography illustrated their anti-nematodal and antiprotozoal activity; the zone of clearance (turbid) was recorded 43, 24, 32 and 37 mm respectively for PM2 through PM10.

The relation between aspiration and oropharyngeal components of swallowing in Amyotrophic Lateral Sclerosis (ALS)

The aim of this study is to examine the relation between aspiration and oral and pharyngeal components of swallowing in patients with ALS. 19 participants diagnosed with ALS followed in outpatient clinic at HC-Unicamp, the patients were underwent to a clinical swallowing evaluation (indirect and direct) and modified barium swallowing evaluation. Results: 63.2% of the participants showed aspiration. Oral escape in the interlabial region with no progression to the anterior lip, slow/weak movement during bolus transport and decreased the wave of the pharyngeal contraction were observed. And also, the results showed positive and moderate correlation between the presence of aspiration and pharyngeal wave pharyngeal function instead of oral phase.