Induction of DnaK upon <i>γ</i>-Irradiation at High and Low Rates in <i>Escherichia coli</i>

DnaK is implicated in protein folding, repair and degradation. Its protective role during heat shock is well documented and many other stresses can also induce its production. Using a competitive ELISA, intracellular DnaK concentrations were determined in Escherichia coli ATCC 25922 exposed to a γ-irradiation dose of 0.3 KGy applied either at high (8 × 10-2 KGy/min) or low rates (3 × 10-3 KGy/min) and with or without a recuperation period of 22 h at 37℃ post-treatment. All four irradiation treatments reduced cell counts similarly and significantly compared to the control (P < 0.0001). However, the highest DnaK concentration was observed in cells irradiated at low rate without recuperation (105,416 molecules/cell;P = 0.0001). Furthermore, DnaK levels remained higher than the control (38,500 molecules/ cell) after the recuperation period (P < 0.05). Variation in the intracellular DnaK concentration indicates that the bacterial stress response was modulated differently according to the irradiation treatment (P = 0.0001).

Exploitation Patterns of Anchovies (Engraulis encrasicolus) by Marine Artisanal Fisheries in Togo (West Africa)

Pelagic fish,including sardines and anchovies(Order Clupeiformes),are the most common species taken by artisanal marine fisheries along the Togolese coast.We investigated fisher involvement as well as fish captures over a period of 10 years,particularly of the European anchovy(Engraulis encrasicolus).Our results indicate that 60%of fishers operated from the Loméfishing harbour,most fishers being Ghanaians working seasonally in Togo.63.7%of all the fishers used canoes with outboards,a higher percentage compared to the previous decades.Seven fishing gear type were identified,with bottom gillnet and surface gillnet being the most commonly used.However,in the most important fishing camp in the country in terms of fish production(Loméfishing harbour),all fishers used shark nets.Overall,fisheries catches did not change significantly across years,but anchovy fishing effort and catch per unit of effort(CPUE)declined over the study period,suggesting some depletion of the species stocks on the Togolese coast and a demotivation of fishers.

Feed supplementation with arginine and zinc on antioxidant status and inflammatory response in challenged weanling piglets

Although supplementing the diet with zinc oxide and arginine is known to improve growth in weanling piglets, the mechanism of action is not well understood. We measured the antioxidant status and inflammatory response in 48 weanling castrated male piglets fed diets supplemented with or without zinc oxide(2,500 mg Zn oxide per kg) and arginine(1%) starting at the age of 20 days. The animals were injected with lipopolysaccharide(100 μg/kg) on day 5. Half of them received another injection on day 12.Blood samples were taken just before and 6, 24 and 48 h after injection and the mucosa lining the ileum was recovered following euthanizing on days 7 and 14. Zinc supplementation increased reduced and total glutathione(GSH)(reduced and total) during days 5 to 7 and arginine decreased oxidized GSH measured on days 5 and 12 and the ratio of total antioxidant capacity to total oxidative status during days12 to 14. Zinc decreased plasma malondialdehyde measured on days 5 and 12 and serum haptoglobin measured on day 12 and increased both metallothionein-1 expression and total antioxidant capacity measured in the ileal mucosa on day 14. Tumour necrosis factor a concentration decreased from days 5 to12(all effects were significant at P < 0.05). This study shows that the zinc supplement reduced lipid oxidation and lipopolysaccharide-induced inflammation during the post-weaning period, while the arginine supplementation had only a limited effect.