RNA-DNA hybrids prevent resection at dysfunctional telomeres

1. Download : Download high-res image (170KB)
2. Download : Download full-size image

     

DNA-based identification of larval cod in stomach contents of predatory fishes

Predator-prey interactions play an influential role in determining the demographics of a population or species. In the Northwest Atlantic, Atlantic cod, Gadus morhua, once the basis of a lucrative commercial fishery, have not recovered despite regulations imposed on the fishery to reduce harvest rates. One possible reason for the lack of recovery is that high predation pressure on juvenile and larval stages, particularly from species such as herring and mackerel, may regulate the abundance of cod. However, traditional methods used to identify larval cod and haddock often fail when applied to partially digested remains. Here, we described a DNA-based assay to identify the presence of digested cod remains from the stomachs of predatory fish species. After development, the assay was tested on two sets of field samples. Larval and juvenile cod were successfully detected in both tests.     

Role of leptin in the stomach and the pancreas

Leptin, a 16 kDa protein encoded by the ob gene, is known mainly for its role in the regulation of food intake, body composition and energy expenditure through a central feedback mechanism. Initially leptin was considered as an ob gene product of adipocytes but recently the presence of leptin and its receptors have been revealed in other organs including gastric mucosa and the pancreas and found to be released from these organs by cholecystokinin (CCK), gastrin and ordinary feeding. Furthermore, leptin was found to mimic the action of CCK on gastric and pancreatic integrity, while reducing the food intake and to affect gastric and pancreatic secretion. This report emphasizes the role of leptin originating from the gastrointestinal tract acting synergistically with CCK at the hypothalamus level on the mechanism of food intake and locally on the protection of gastric mucosa and the pancreas against noxious agents and to maintain tissue integrity.