Direct interaction between marine cyanobacteria mediated by nanotubes.

Microbial associations and interactions drive and regulate nutrient fluxes in the ocean. However, physical contact between cells of marine cyanobacteria has not been studied thus far. Here, we show a mechanism of direct interaction between the marine cyanobacteria Prochlorococcus and Synechococcus, the intercellular membrane nanotubes. We present evidence of inter- and intra-genus exchange of cytoplasmic material between neighboring and distant cells of cyanobacteria mediated by nanotubes. We visualized and measured these structures in xenic and axenic cultures and in natural samples. We show that nanotubes are produced between living cells, suggesting that this is a relevant system of exchange material in vivo. The discovery of nanotubes acting as exchange bridges in the most abundant photosynthetic organisms in the ocean may have important implications for their interactions with other organisms and their population dynamics.

Consumption of dietary n-3 fatty acids decreases fat deposition and adipocyte size, but increases oxidative susceptibility in broiler chickens.

The aim of this study was to determine the effects of an omega-3 (n-3) polyunsaturated fatty acid (PUFA)-enriched diet on animal fat depots and lipid oxidation in the blood and meat of broiler chickens. Abdominal fat pad (AFP), sartorius muscle and liver histology were used to assess the effect of the dietary fat on animal lipid depots. A total of 60 female broilers (14 days old) was randomly divided into two groups which received a diet containing 10 % of tallow (S diet), rich in saturated fatty acids or 10 % of a blend of fish oil and linseed oil (N3 diet), rich in n-3 PUFA from 14 to 50 days of life. Both absolute and relative weights of AFP in N3 animals were lower than in the S group (P < 0.05). These results paralleled with a lower adipocyte mean area (P < 0.001) obtained in N3-fed animals, leading to a higher number of fat cells per unit of surface measured (383.4 adipocytes/mm(2) vs. 273.7 adipocytes/mm(2)). Similarly, fat content and the intramuscular fat-occupied area of muscle were lower in N3 (P < 0.0001) than in the S-fed birds. Neither macroscopic nor microscopic differences were observed in the liver. The inclusion of dietary n-3 PUFA increased meat and erythrocyte oxidation susceptibility; however, the erythrocytes from the S group were less resistant to osmotic changes. Results indicate that feeding an n-3 PUFA diet influences fat distribution and the oxidative status of broiler chickens.