Correlation of pheromone-binding protein–ligand equilibrium dissociation constants with electroantennogram response patterns
Bibliographic record
Abstract
Pheromone-binding proteins (PBPs) are water-soluble proteins found at high concentration in the lymph fluid of pheromone-sensing hairs on insect antennae. PBPs could function as pheromone transporters, ferrying the hydrophobic odorants to their cognate odorant receptors. However, it is also possible for these proteins to bind the odorants near the dendritic membrane of pheromone-sensing neurons and, therefore, function as scavengers. The two functions are not mutually exclusive. In this paper, the transporter and (or) scavenger roles of PBPs in pheromone perception were investigated using the pheromone of the gypsy moth (7R, 8S)-epoxy-2-methyloctadecane and analogues with heteroatom (O or S) substitutions in the hydrocarbon chain. PBP–ligand equilibrium dissociation constants (Kd) were correlated with electroantennogram (EAG) response patterns of male gypsy moth antennae to the pheromone, its enantiomer, and their respective analogues. EAG measures the potential drop across the antenna due to odorant receptor activation and subsequent ion channel opening. Three quantifiable properties of the EAG responses were used: lag times from stimulus to response onset, depolarization rates (rate of receptor activation), and repolarization rates (rate of receptor deactivation). Negative correlations were observed between Kd and lag times and between Kd and repolarization rates. Positive correlations were seen with Kd against depolarization rates. The inverse relationship of Kd constants with lag times and the direct relationship with depolarization rates strongly supports transporter function of PBPs. Interestingly, the inverse correlation of Kd constants with repolarization rates suggests a scavenger effect. These results indicate that PBP affects odorant receptor activity through both odorant transport and scavenger functions. Through differences in ligand binding affinities, PBPs influence pheromone availability for receptor activation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".