Notice bibliographique
Résumé
Naked mole-rats are fascinating little creatures. They live in large social colonies underground, where they eat tubers, dig tunnels, defend their colony from predators and reproduce. That last one, however, is usually restricted to just the dominant female of the colony (the queen) and a dominant male. This means that the vast majority of the colony, including all the subordinate females, do not produce offspring. Physiologically, these females are unable to have young because their fertility is reduced – meaning that the hormonal signalling pathway from their brain to their ovaries is apparently suppressed. However, this suppression seems to be alleviated when the subordinate females are taken away from their colony: within a week, their fertility is restored and they are able to reproduce once again. To figure out what mechanism is behind this suppression of reproduction in the subordinate females, Daniel Hart, Erin Roberts and colleagues at the Universities of Pretoria and Cape Town in South Africa took a closer look at the physiology of the females in their naked mole-rat colonies.An important player in the hormonal signalling pathway needed for reproduction is luteinizing hormone, which tends to be lower in subordinate naked mole-rats compared with the queens. Luteinizing hormone is produced by the pituitary gland, just beneath the brain, and signals to the ovaries to make the changes required for reproduction. When these changes are complete, the ovaries signal back to the brain and pituitary to say, ‘that's enough’, and they respond by shutting down luteinizing hormone production in a process called negative feedback. The researchers thought that negative feedback may be overactive in subordinates, leading to lower luteinizing hormone and reproductive dysfunction. To test this, they surgically removed the ovaries of queens and subordinate females to remove these negative feedback signals and measured the luteinizing hormone levels in the animals’ blood, expecting a greater luteinizing hormone rise in subordinates than in queens. However, luteinizing hormone levels rose similarly in both, so this probably wasn't the fertility-suppressing culprit.Next, they turned their attention to their second suspect in the search for the reproductive disruptor: the stress response. Why? Because the queen is a bit of a bully, with a tendency to shove and even bite her subordinates. When animals experience a stressful situation, they produce the hormone cortisol to help them cope and, in some species, cortisol can reduce fertility. They measured cortisol in the blood of queens and subordinate females and found, unexpectedly, that the stress hormone was lower in the blood of the subordinates. Given cortisol levels were not high in the subordinates, this stress hormone was probably not the culprit either.When stressed, animals can produce their own pain relievers, called endogenous opioid peptides. These internally produced pain relievers can interfere with fertility and so were suspect number three. Using a drug called naloxone, Hart, Roberts and colleagues blocked the ability of these pain relievers to work and then measured the animals’ luteinizing hormone levels, expecting the blockade of internally produced pain relievers to enhance the rise in hormone levels. Instead, they saw the opposite: luteinizing hormone barely rose when the subordinate naked mole-rat females were treated with naloxone, suggesting that endogenous opioid peptide pain relievers aren't interfering with the subordinate naked mole-rats’ fertility.It seems that feedback signals from the ovaries that reduce luteinizing hormone levels, stress and internally produced pain relievers are not responsible for the suppression of the subordinate naked mole-rats’ fertility. Now that the researchers have ruled out these major suspects, they've set their sights on some new suspects for investigation, including the multifunctional hormone prolactin. So, the curious case of how these social, subterranean, sparsely haired rodents regulate their reproduction based on rank remains to be unravelled.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,010 | 0,002 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».