Ring position in cyclopropene fatty acids and stearic acid desaturation in hen liver

Four cyclopropene fatty acids, having the double bond of the cyclopropene ring at the 8,9, 9,10, 10,11 and 11,12 positions, respectively, were tested as inhibitors of stearic acid desaturation by the desaturase enzyme system of hen liver. The first three were powerful inhibitors, but the last was not. The cyclopropene acids with the 9,10 and 10,11 double bonds were equally strong inhibitors, while the acid with the 8,9 double bond was less effective. To account for the specificity of those cyclopropene fatty acids in which the C9 or C10 carbon atom is included in the cyclopropene ring, it is suggested that the conformation and structure of the CoA derivatives of these acids is such that they can irreversibly occupy the site on the enzyme responsible for 9,10-desaturation.     

Pilot proteomic analysis of cerebrospinal fluid in Alzheimer's disease

Proteomic analysis of cerebrospinal fluid (CSF) holds great promise in understanding the progression of neurodegenerative diseases, including Alzheimer's disease (AD). As one of the primary reservoirs of neuronal biomolecules, CSF provides a window into the biochemical and cellular aspects of the neurological environment. CSF can be drawn from living participants allowing the potential alignment of clinical changes with these biochemical markers. Using cutting-edge mass spectrometry technologies, we perform a streamlined proteomic analysis of CSF. We quantify greater than 700 proteins across 10 pairs of age- and sex-matched participants in approximately one hour of analysis time each. Using the paired participant study structure, we identify a small group of biologically relevant proteins that show substantial changes in abundance between cognitive normal and AD participants, which were then analyzed at the peptide level using parallel reaction monitoring experiments. Our findings suggest the utility of fractionating a single sample and using matching to increase proteomic depth in cerebrospinal fluid, as well as the potential power of an expanded study.     

Mechanisms of Na2SO4-induced accelerated oxidation

The effect of sodium sulphate coatings on the oxidation of cobalt-base alloys at 900°C in oxygen at 1 atm pressure has been studied. The oxidation of pure cobalt is rather slower with a sodium sulphate coating than without; and this is also true of cobalt-chromium alloys. However, the oxidation of cobalt-tungsten alloys is accelerated by the presence of a sodium sulphate layer: a porous CoO scale develops, with an accumulation of a tungsten-rich oxide at the metal surface. Cobalt-molybdenum alloys suffer an even greater acceleration, and unlike the tungsten-containing alloys the rate does not fall as the oxide at the surface becomes protective, possibly due to the higher volatility of MoO_s. It is possible to produce a similar rapid corrosion of pure cobalt with sodium sulphate-sodium tungstate coating.It is concluded that basic fluxing of CoO does not take place, either because there is no salt-soluble anionic species analogous to the nickelate ion, or because it is stable at salt basicities higher than those reached in these experiments. The accelerated attack in the presence of tungsten or molybdenum is thought to be due to acid fluxing of the cobalt.Chromium has little effect on the acid fluxing of cobalt-tungsten alloys until the chromium-content is high enough for the establishment of a continuous Cr₂O₃ layer; this does not then suffer accelerated attack in the presence of sodium sulphate.A sodium carbonate layer has a similar accelerating effect on the tungsten and molybdenum containing alloys except that there is an incubation period before rapid attack commences. This may be associated with the decomposition of the salt with the evolution of CO₂.     

Renal proliferative and phenotypic changes in rats with two-kidney, one-clip Goldblatt hypertension

Previous research in this laboratory has shown that preweaning and postweaning juvenile meadow voles, Microtus pennsylvanicus, can acquire a spatial task, the Morris water-maze task. The present study examined the influence of age of juvenile acquisition ("before weaning" (BW; Day 10 and 15 after birth) and "after weaning" (AW; Day 20 and 25 after birth)) of a spatial task on subsequent re-acquisition of the same hidden-platform spatial water-maze task. This study also compared sex differences and litter sex-ratio effects on reacquisition performance. Fifteen litters of adults were re-tested in the same water maze 6 weeks after being initially tested as juveniles. All analyses were conducted using a covariate that removed the group differences in the original task performance. Adult voles from female-biased litters, that had previously learned the task at an older juvenile age (AW), reacquired the same task faster than adults that had previously learned the task at a younger juvenile age (BW). In the adult BW group there was also a significant litter sex-ratio effect such that voles born into a female-biased litter re-acquired the task more slowly than did voles born into a male-biased litter. There were no significant sex or litter sex-ratio effects on spatial learning in the AW group. These results show that adult meadow voles can require a spatial task more quickly if they initially learned the task at an older juvenile age, suggestive of a period of infantile amnesia. In addition, these results indicate that the litter sex-ratio can affect adult spatial performance, suggesting that the relative amount of androgens in utero may influence the development of sexually-dimorphic spatial ability in adulthood.