Effects of exposure to 17alpha-ethinylestradiol during early development on sexual differentiation and induction of vitellogenin in zebrafish (Danio rerio)

The effect of acute stress on plasma beta-corticosterone (B), testosterone (T) and estradiol-17beta (E2) concentrations in juvenile alligators collected from sites with varying sediment contaminants was examined in this study. Dramatic increases in plasma B concentrations were observed in alligators from all of the sites after 2 h of capture although females from the intermediate contaminant site exhibited a significantly lower percentage increase in B than females from the other two sites. Males from the site with the highest contaminant levels exhibited elevated initial B concentrations relative to the other sites. This pattern was not observed after 2 h of restraint. Females from the highest contaminant site exhibited depressed initial T when compared to the other sites although this pattern was not observed after 2 h of restraint. Neither E2 nor T decreased after 2 h in females, whereas T concentrations decreased in all males over the same time period. The variance associated with these endpoints was also examined to determine whether it could serve as a more sensitive marker for perturbations of the endocrine system and stress response. Females from the higher and intermediate contaminant sites exhibited the lowest and highest standard errors (respectively) associated with 2 h plasma B concentrations with no differences among mean concentrations suggesting a perturbation of the stress response in these animals that was not detected by examining the means. We concluded that the environmental contaminants could be acting as stressors, leading to the observed differences.     

Nanoinjection as a tool to mimic vertical transmission of Flavobacterium psychrophilum in rainbow trout Oncorhynchus mykiss

Newly fertilised eggs of rainbow trout Oncorhynchus mykiss were nanoinjected with Flavobacterium psychrophilum in order to mimic vertical transmission. Two bacterial isolates with different elastin-degrading capacity were used. All infected groups (10, 100 and 1000 colony forming units egg(-1)) showed significantly higher cumulative mortalities than the control groups at the end of the experiment, 70 d post-hatching. The total mortalities in the control groups were below 2.5%. In the high-dose groups, 95 to 100% of the eggs died during the eyed stage. In the intermediate group infected with the elastin-negative isolate, the major mortality occurred during the eyed stage of the egg, with a total cumulative mortality of 83% at the end of the experiment. In the intermediate group infected with the elastin-positive isolate, a total mortality of 63% was recorded. In this group, diseased fry showed clinical signs of disease and morphological changes similar to those described in connection with rainbow trout fry syndrome (RTFS) shortly after the beginning of feeding. In the low dose groups, the mortality in the elastin-negative group was 14% and in the elastin-positive group 11%. The bacterium was isolated from dead eggs and fry in infected groups and demonstrated in internal organs of dead and moribund fry by immunohistochemistry. The nanoinjection method used in this study may be a useful method to study pathogens, like F. psychrophilum, that can be vertically transmitted.     

Long-term history of land-use and vegetation at Ire,an agriculturally marginal area in Blekinge,south Sweden

Pollen records from a small lake and a small peatland at Ire in northern Blekinge, Sweden, reveal that until a.d. 300 there was a mixed deciduous type of woodland dominated by Quercus, Tilia and Corylus, with Betula, Pinus, Populus, Fraxinus, Ulmus and Acer as important constituents. The first, but weak, signs of human influence on the vegetation are detected around 2300 b.c. At this time, the area was probably used for woodland grazing. The regional expansion of Fagus occurred around 100 b.c.–a.d. 200, and later, at about a.d. 500, woods dominated by Fagus were common in the area. Around a.d. 600–700 an isolated farmstead may have been established in the area, as single pollen grains of Secale (rye) were found. This farmstead may represent the first permanent settlement in the area. A more widespread opening of the vegetation occurred around a.d. 1000, probably as an effect of a more pronounced use of the area, and an expansion of settlements in the region. The openness of the area seems to have peaked around a.d. 1400–1800, and during this period the vegetation was highly fragmented with small stands of woodland, intensively grazed pastures, and arable fields where Secale and Triticum were mainly cultivated. Around a.d. 1600 Fagus pollen percentages sharply decrease, most probably caused by a deliberate and selective felling of beech trees for the production of potash, which consumed enormous amounts of wood. Picea seems to have been established around a.d. 1600, but it did not become a regional dominant until the first part of the 20th century, when land use decreased and it became favoured by forestry.     

Two-electron electrochemical oxidation of quercetin and kaempferol changes only the flavonoid C-ring

Bulk electrolysis of the antioxidant flavonoids quercetin and kaempferol in acetonitrile both yield a single oxidation product in two-electron processes. The oxidation products are more polar than their parent compounds, with an increased molecular weight of 16 g/mol, and were identified as 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone and 2-(4-hydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone for quercetin and kaempferol, respectively. Two-electron oxidation of the parent flavonoid is suggested to yield a 3,4-flavandione with unchanged substitution pattern in the A- and B-ring, which may rearrange to form the substituted 3(2H)-benzofuranone through the chalcan-trione ring-chain tautomer. The acidity of the 3-OH group is suggested to determine the fate of the flavonoid phenoxyl radical, originally formed by one-electron oxidation, as no well-defined oxidation product of luteolin (lacking the 3-OH group) could be isolated despite rather similar half-peak potentials: E_P/2 = 0.97 V, 0.98 V and 1.17 V vs. NHE for quercetin, kaempferol and luteolin, respectively, as measured by cyclic voltammetry in acetonitrile.     

Multisensory Interactions between Vestibular,Visual and Somatosensory Signals

Vestibular inputs are constantly processed and integrated with signals from other sensory modalities, such as vision and touch. The multiply-connected nature of vestibular cortical anatomy led us to investigate whether vestibular signals could participate in a multi-way interaction with visual and somatosensory perception. We used signal detection methods to identify whether vestibular stimulation might interact with both visual and somatosensory events in a detection task. Participants were instructed to detect near-threshold somatosensory stimuli that were delivered to the left index finger in one half of experimental trials. A visual signal occurred close to the finger in half of the trials, independent of somatosensory stimuli. A novel Near infrared caloric vestibular stimulus (NirCVS) was used to artificially activate the vestibular organs. Sham stimulations were used to control for non-specific effects of NirCVS. We found that both visual and vestibular events increased somatosensory sensitivity. Critically, we found no evidence for supra-additive multisensory enhancement when both visual and vestibular signals were administered together: in fact, we found a trend towards sub-additive interaction. The results are compatible with a vestibular role in somatosensory gain regulation.