Core temperature variability in diving king penguins (Aptenodytes patagonicus): a preliminary analysis

Core temperature was determined in two king penguins living in the wild at Ile de la Possession, Crozel Archipelago, using implantable four-channel temperature loggers. Core temperatures derived from bird no. 1 (sensor placed under the sternum, in the vicinity of the liver and upper stomach) were closely correlated with diving activity (as determined by an external light recorder), and ranged from 38.3°C, (on land) to a minimum of 37.2°C during a dive. Core temperatures measured in bird no. 2 showed that temperatures near the heart were generally 1°C lower than those under the sternum or in the lower abdomen. Core temperatures declined continuously during dives (by 0.8, 1.2 and 2.7°C in the lower abdomen, under the sternum and near the heart, respectively) and showed precipitous drops to 35°C, probably associated with ingestion of food. Temperatures measured near the heart fluctuated over a period of 288 s, corresponding to the duration (from the literature) of the surface/dive cycle. The relevance of these findings with respect to diving physiology, blood perfusion of tissues, tissue metabolism and aerobic dive limits is discussed.     

Structures and contribution to the antigenicity of oligosaccharides of Japanese cedar (Cryptomeria japonica) pollen allergenCry j I: relationship between the structures and antigenic epitopes of plantN-linked complex-type glycans

The oligosaccharide structures ofCry j I, a major allergenic glycoprotein ofCryptomeria japonica (Japanese cedar, sugi), were analysed by 400 MHz¹H-NMR and two-dimensional sugar mapping analyses. The four major fractions comprised a series of biantennary complex type N-linked oligosaccharides that share a fucose/xylose-containing core and glucosamine branches including a novel structure with a nongalactosylated fucosylglucosamine branch.Rabbit polyclonal anti-Cry j I IgG antibodies cross-reacted with three different plant glycoproteins having the same or shorter N-linked oligosaccharides asCry j I. ELISA and ELISA inhibition studies with intact glycoproteins, glycopeptides and peptides indicated that both anti-Cry j I IgGs and anti-Sophora japonica bark lectin II (B-SJA-II) IgGs included oligosaccharide-specific antibodies with different specificities, and that the epitopic structures against anti-Cry j I IgGs include a branch containing 1–6 linked fucose and a core containing fucose/xylose, while those against anti-B-SJA-II IgGs include nonreducing terminal mannose residues. The cross-reactivities of human allergic sera to miraculin andClerodendron Trichotomum lectin (CTA) were low, and inhibition studies suggested that the oligosaccharides onCry j I contribute little or only conformationally to the reactivity of specific IgE antibodies.Abbreviations Cry j I a major allergenic glycoprotein ofCryptomeria japonica - B-SJA-II Sophora japonica bark lectin II - CTA Clerodendron trichotomum lectin - TFMS trifluoromethanesulfonic acid - HRP horseradish peroxidase     

Protein utilization during starvation in fat and lean Svalbard ptarmigan (Lagopus mutus hyperboreus)

Summary Body protein sparing during starvation has been examined in fat and lean Svalbard ptarmigan. Protein utilization was determined from daily N excretion and from the rate of decrease in body mass. Changes in plasma concentrations of -hydroxybutyrate, free fatty acids, glucose, and uric acid were also recorded. When fat birds were starved for 15 days protein catabolism initially fell (phase I) and was thereafter kept low (phase II). This was evident from the temporal pattern in both N excretion and body mass loss. In two birds, N excretion eventually increased, revealing enhanced protein catabolism and thus a third phase of starvation. Changes in protein utilization were paralleled by changes in plasma uric acid. Approximately 9% of the energy demand was covered by breakdown of body protein during phase II. The importance of fat catabolism in providing energy was indicated by markedly elevated plasma levels of -hydroxybutyrate and free fatty acids. When lean birds were starved for 5 days there appeared to be no phase II. The temporal pattern of body mass loss indicated phase I and III but that of N excretion only phase III. The relative contribution of body protein to energy demand increased from 22% at day 2 to 41% at the end of starvation and was paralleled by increased plasma uric acid. When data from lean and fat birds were pooled, the changes in uric acid and N excretion were highly correlated (r=0.92, P<0.001), indicating that plasma uric acid is a reliable index of protein breakdown in starving Svalbard ptarmigan. In conclusion, starving fat Svalbard ptarmigan have a much greater capacity to spare body protein than lean birds. Fat birds effectively reduce protein catabolism and maintain this at a low level whereas starving lean birds increase protein catabolism.Abbreviations -OHB -hydroxybutyrate - BM body mass - BMR basal metabolic rate; dne daily nitrogen excretion - FFA free fatty acids - MR metabolic rate     

Diacylglycerol kinase η colocalizes and interacts with apoptosis signal-regulating kinase 3 in response to osmotic shock

Diacylglycerol kinase (DGK) η translocates from the cytoplasm to punctate vehicles via osmotic shock. Apoptosis signal-regulating kinase (ASK) 3 (MAP kinase kinase kinase (MAPKKK) 15) is also reported to respond to osmotic shock. Therefore, in the present study, we examined the subcellular localization of DGKη and ASK3 expressed in COS-7 cells under osmotic stress. We found that DGKη was almost completely colocalized with ASK3 in punctate structures in response to osmotic shock. In contrast, DGKδ, which is closely related to DGKη structurally, was not colocalized with ASK3, and DGKη failed to colocalize with another MAPKKK, C-Raf, even under osmotic stress. The structures in which DGKη and ASK3 localized were not stained with stress granule makers. Notably, DGKη strongly interacted with ASK3 in an osmotic shock-dependent manner. These results indicate that DGKη and ASK3 undergo osmotic shock-dependent colocalization and associate with each other in specialized structures.     

Spatial segregation of four coexisting processional termites (Termitidae: Nasutitermitinae) in tropical rainforest

In Lambir Hills National Park, Sarawak, Malaysia, there are four species of processional termites that coexist: Hospitalitermes hospitalis, H. lividiceps, H. rufus and Longipeditermes longipes. This paper presents the results of our investigation on the spatial distribution of nests and the foraging activities of the four species in coexistence. The results show that there are fairly marked differences in nesting sites, as well as in foraging activities, among the four species. It is noteworthy that H. rufus inhabits only the canopy area over 20 m above ground, apparently segregated from the other three species, and that their foraging activities are limited also to tree canopies over 10 m above ground. In contrast, L. longipes nests underground and forages exclusively on the forest floor. Hospitalitermes hospitalis and H. lividiceps inhabit and forage over wide areas, from the forest floor to tree canopies. The upper parts of the tree canopy (over 10 m) are also foraging territories of the secluded H. rufus, but there were no observations of simultaneous foraging of the three Hospitalitermes species in the same canopy areas.     

Protein Kinase A-dependent Phosphorylation of Rap1 Regulates Its Membrane Localization and Cell Migration

The small G protein Rap1 can mediate “inside-out signaling” by recruiting effectors to the plasma membrane that signal to pathways involved in cell adhesion and cell migration. This action relies on the membrane association of Rap1, which is dictated by post-translational prenylation as well as by a stretch of basic residues within its carboxyl terminus. One feature of this stretch of acidic residues is that it lies adjacent to a functional phosphorylation site for the cAMP-dependent protein kinase PKA. This phosphorylation has two effects on Rap1 action. One, it decreases the level of Rap1 activity as measured by GTP loading and the coupling of Rap1 to RapL, a Rap1 effector that couples Rap1 GTP loading to integrin activation. Two, it destabilizes the membrane localization of Rap1, promoting its translocation into the cytoplasm. These two actions, decreased GTP loading and decreased membrane localization, are related, as the translocation of Rap1-GTP into the cytoplasm is associated with its increased GTP hydrolysis and inactivation. The consequences of this phosphorylation in Rap1-dependent cell adhesion and cell migration were also examined. Active Rap1 mutants that lack this phosphorylation site had a minimal effect on cell adhesion but strongly reduced cell migration, when compared with an active Rap1 mutant that retained the phosphorylation site. This suggests that optimal cell migration is associated with cycles of Rap1 activation, membrane egress, and inactivation, and requires the regulated phosphorylation of Rap1 by PKA.     

Modulation of Lipid Kinase PI4KIIα Activity and Lipid Raft Association of Presenilin 1 Underlies γ-Secretase Inhibition by Ginsenoside (20S)-Rg3

Amyloid β-peptide (Aβ) pathology is an invariant feature of Alzheimer disease, preceding any detectable clinical symptoms by more than a decade. To this end, we seek to identify agents that can reduce Aβ levels in the brain via novel mechanisms. We found that (20S)-Rg3, a triterpene natural compound known as ginsenoside, reduced Aβ levels in cultured primary neurons and in the brains of a mouse model of Alzheimer disease. The (20S)-Rg3 treatment induced a decrease in the association of presenilin 1 (PS1) fragments with lipid rafts where catalytic components of the γ-secretase complex are enriched. The Aβ-lowering activity of (20S)-Rg3 directly correlated with increased activity of phosphatidylinositol 4-kinase IIα (PI4KIIα), a lipid kinase that mediates the rate-limiting step in phosphatidylinositol 4,5-bisphosphate synthesis. PI4KIIα overexpression recapitulated the effects of (20S)-Rg3, whereas reduced expression of PI4KIIα abolished the Aβ-reducing activity of (20S)-Rg3 in neurons. Our results substantiate an important role for PI4KIIα and phosphoinositide modulation in γ-secretase activity and Aβ biogenesis.     

Synthesis and Herbicidal Activity of 6-Phenyl-5-Propylamino-2-Pyrazinecarbonitriles and Related Compounds

6-Phenyl- and 5-phenyl-2-pyrazinecarbonitriles with or without a propylamino group at the 3-, 5- or 6-position of the pyrazine ring were prepared together with some related compounds from the corresponding 2,3-pyrazinedicarbonitriles. Their herbicidal activities against barnyardgrass and broadleaf weeds were examined in pot tests. The 6-phenyl-2-pyrazinecarbonitriles were relatively potent compared with the 5-phenyl derivatives. Moreover, the presence of a propylamino group at the 5-position of the 6-phenyl-2-pyrazinecarbonitriles was closely related to an increase in activity.