Comparison of the biochemical composition of normal epidermal mucus and extruded slime of hagfish (Myxine glutinosa L.).

Hagfish (Myxine glutinosa) secrete normal epidermal mucus and extruded slime. The epidermal mucus is produced continuously to prevent pathogen adherence while the extruded slime is observed predominantly during feeding, provocation or stress. To date little is known about the involvement of extruded slime in the physiological functions of hagfish. In this preliminary study, innate immune enzymes and the protein composition of hagfish normal epidermal mucus and extruded slime were analysed and compared. The lysozyme specific activity of hagfish was observed approximately two-fold higher in extruded slime than that of epidermal mucus. The extruded slime had approximately 3.5-5.0 fold increased levels of alkaline phosphatase, cathepsin B and proteases in comparison to epidermal mucus. Protease characterization using specific inhibitors showed that the extruded slime had higher levels of serine trypsin-like proteases compared to metalloproteases whereas epidermal mucus showed equal proportion of both serine and metalloproteases. SDS-PAGE analysis showed high levels of three proteins with molecular masses in the range of 13-16kDa in the extruded slime. The LC/MS/MS analysis of protein bands 1, 2 and 3 showed closest matches to hemoglobulin-3, histone H3 and H2B proteins, respectively. The observation of elevated levels of innate immune parameters in the extruded slime suggested that the extruded slime has a significant role in innate immunity of hagfish against infectious pathogens.

Lepeophtheirus salmonis: characterization of prostaglandin E(2) in secretory products of the salmon louse by RP-HPLC and mass spectrometry.

Lepeophtheirus salmonis is an ectoparasitic copepod that causes serious disease outbreaks in both wild and farmed salmonids. As the relationship between L. salmonis and its hosts is not well understood, the current investigation was undertaken to investigate whether any immunomodulatory compounds could be identified from secretions of L. salmonis. By incubating live L. salmonis adults with the neurotransmitter dopamine in seawater, we were able to obtain secretions from the parasite. These were analyzed by RP-HPLC column, as well as LC-MS. L. salmonis secretions contained a compound with the same retention time and mass of PGE(2). The identity of this compound as PGE(2) was confirmed by MS-in source dissociation. The concentrations of PGE(2) in L. salmonis secretions ranged from 0.2 to 12.3 ng/individual and varied with incubation temperature and time kept off the host. Prostaglandin E(2) is a potent vasodilator and thought to aid in parasite evasion from host immune responses. This is the first reported evidence of prostaglandin production in parasitic copepod secretions and its implications for the host-parasite relationship are discussed.

Feeding rats diets enriched in lowbush blueberries for six weeks decreases ischemia-induced brain damage.

Oxidative stress is an important element in the etiology of ischemic stroke. Lowbush blueberries (Vaccinium angustifolium Aiton) have a high antioxidant capacity and thus we determined whether consumption of lowbush blueberries would protect neurons from stroke-induced damage. Rats were fed AIN-93G diets containing 0 or 14.3% blueberries (g fresh weight/100 g feed) for 6 weeks. Stroke was then simulated by ligation of the left common carotid artery (ischemia), followed by hypoxia. One week later, plasma and urine were collected, and neuronal damage in the hippocampus was determined histologically. In control rats, hypoxia-ischemia resulted in 40 +/- 2% loss of neurons in the hippocampus of the left cerebral hemisphere, as compared to the right hemisphere. Rats on blueberry-supplemented diets lost only 17 +/- 2% of neurons in the ischemic hippocampus. Neuroprotection was observed in the CA1 and CA2 regions, but not CA3 region, of the hippocampus. The blueberry diet had no detectable effects on the plasma or urine oxygen radical absorbance capacity (ORAC) or plasma lipids. We conclude that consumption of lowbush blueberries by rats confers protection to the brain against damage from ischemia, suggesting that inclusion of blueberries in the diet may improve ischemic stroke outcomes.

UDP-N-trifluoroacetylglucosamine as an alternative substrate in N-acetylglucosaminyltransferase reactions.

The synthesis of UDP-N-trifluoroacetylglucosamine [uridine 5'-(2-trifluoroacetamido-2-deoxy-alpha-D-glucopyranosyl diphosphate, UDP-GlcNAc-F3] is reported. The compound is found to serve as a substrate for the core-2 GlcNAc transferase (EC 2.4.1.102) that is involved in the biosynthesis of O-linked glycoproteins and for the GlcNAcT-V transferase (EC 2.4.1.155) that is a key biosynthetic enzyme controlling the branching pattern of cell surface complex Asn-linked oligosaccharides. The trisaccharide beta-D-Galp-(1-->3) -[beta-D-GlcpNAc-F3(1-->6)] alpha-D-GalpNAc-OR [R = (CH2)8CO2Me] was prepared from beta-D-Galp-(1-->3) -alpha-D- GalpNAc-OR using the core-2 GlcNAc transferase. The tetrasaccharide beta-D-GlcpNAc-(1 -->2)-[beta-D-GlcpNAc-F3-(1-->6)]-alpha-D-Manp-(1-->6)-beta-D-Glcp -OR [R = (CH2)7CH3] using the GlcNAcT-V transferase. Removal of the trifluoroacetyl group was achieved under mild basic conditions to give the corresponding glucosamine containing tetrasaccharide. These examples demonstrate the feasibility of introducing masked forms of glucosamine residues into oligosaccharides using GlcNAc-specific transferases. The requirement for the trifluoroacetamido group as a specific recognition element was evident in the observation that neither UDP-glucosamine nor UDP-glucose served as a donor substrates for the core-2 GlcNAc transferase.

Resistance and aerobic training in older men: effects on VO2peak and the capillary supply to skeletal muscle.

Both aerobic training (AT) and resistance training (RT) may increase aerobic power (VO2peak) in the older population; however, the role of changes in the capillary supply in this response has not been evaluated. Twenty healthy men (age 65-74 yr) engaged in either 9 wk of lower body RT followed by 9 wk of AT on a cycle ergometer (RT-->AT group) or 18 wk of AT on a cycle ergometer (AT-->AT group). RT was performed three times per week and consisted of three sets of four exercises at 6-12 repetitions maximum. AT was performed three times per week for 30 min at 60-70% heart rate reserve. VO2peak was increased after both RT and AT (P < 0.05). Biopsies (vastus lateralis) revealed that the number of capillaries per fiber perimeter length was increased after both AT and RT (P < 0.05), paralleling the changes in VO2peak, whereas capillary density was increased only after AT (P < 0.01). These results, and the finding of a significant correlation between the change in capillary supply and VO2peak (r = 0.52), suggest the possibility that similar mechanisms may be involved in the increase of VO2peak after high-intensity RT and AT in the older population.

Quantitating the capillary supply and the response to resistance training in older men.

Resistance training (RT) has been shown to increase aerobic power in older humans. To determine the effects of RT on the capillary supply in this population, nine older men (65-74 y) engaged in 9 weeks RT of the lower body. Following RT, peak O2 uptake (V.O2,peak) increased by 7% (P<.01). Needle biopsies (vastus lateralis muscle) revealed significant increases (mean +/- SE) in fibre area (3,874 +/- 314 microm2 to 4,778 +/- 309 microm2), fibre perimeter (P, 262 +/- 11 microm to 296 +/- 11 microm), capillary contacts (3.7 +/- .2 to 4.3 +/- .3) and the individual capillary-to-fibre ratio (C:Fi, 1. 33 +/- .32 to 1.61 +/- .37, P<.005). To evaluate the potential for blood-tissue exchange, both fibre area-based and perimeter-based measures of the capillary supply were compared. While the area-based measures were maintained, C:Fi/P was increased, consistent with an increase in the size of the fibre-capillary interface and thus, an increased potential for oxygen flux following RT. Of the measurements of capillary supply, V.O2,peak correlated best with C:Fi/P (r = 0.69, P<.005). These results indicate a significant increase in the capillary supply relative to the perimeter, but not the cross-sectional area, of the muscle fibres following RT in older men, and that C:Fi/P is strongly correlated to the V.O2,peak in this population.