Preferential utilization of ketone bodies for the synthesis of myelin cholesterol in vivo

1. The distribution of radioactivity among lipid classes of myelin and other subcellular brain fractions of young rats (18-21 days) was determined after in vivo injection of (3-(14)C-labelled ketone bodies, [U-(14)C] glucose or [2-(14)C] glucose. 2. The incorporation ratios (sterol/fatty acids) were 0.67, 1.48, 0.25, 0.62 and 0.54 for whole brain, myelin, mitochondria, microsomes and synaptosomes, respectively, with (3-(14)C)-labelled ketone bodies as substrate and 0.37, 0.89, 0.19, 0.34 and 0.29 with [U-(14)C] glucose as substrate. These data show that, both in whole brain and in subcellular brain fractions, acetyl groups derived from ketone bodies are used for sterol synthesis to a large extent than acetyl groups originating from glucose. 3. The specific radioactivity of cholesterol is much higher in myelin than in whole brain or in the other brain fractions, particularly after administration of labelled ketone bodies as substrate. 4. The incorporation patterns of acetoacetate and D-3-hydroxybutyrate were very similar, indicating that both ketone bodies contribute acetyl groups for lipid synthesis via the same metabolic route. 5. Our data suggest that a direct metabolic path from ketone bodies towards cholesterol exists - possibly via acetoacetyl-CoA formation in the cytosol of brain cells - and that this process is most active in oligodendrocytes.     

Rumen microbial growth rates and yields: effect of amino acids and protein.

Effects of amino acids upon microbial growth, optimum ratio of nonprotein to amino acid nitrogen for microbial growth, and incorporation of amino acids into microbial cells were determined with washed cell suspension in vitro as were rumen microbial cells. Rumen microbial dry matter, nitrogen, ribonucleic acid, deoxyribonucleic acid, and substrate disappearance was greatest when a mixture of 18 amino acids was substituted for urea. Substitutions of mixtures of 10 essential amino acids, 8 nonessential amino acids, and sulfur containing amino acids and glutamate also stimulated microbial growth. Acid hydrolyzed casein markedly improved microbial growth. Branched amino acid addition did not affect growth. The optimum ratio of nonprotein to amino acid nitrogen for microbial growth was 75% urea nitrogen and 25% amino acid nitrogen. With this amount of amino acids, an average of 53% of added amino acid was incorporated into microbial cells, 14% was fermented to carbon dioxide and volatile fatty acids, and 33% remained in the supernatant. Both 100% urea and 100% amino acid in growth media were unfavorable for maximal microbial growth. With all carbohydrate substrates, 100% urea nitrogen supported the growth of 9 mg bacterial dry matter per 100 mg of substrate. Substitutions of amino acids for urea increased yields to over 20 mg/100 mg. Microbial growth yields in incubations under carbon dioxide were less than when flasks were flushed with nitrogen. However, yield of bacterial dry matter per unit of substrate was less under nitrogen than under carbon dioxide.     

Range of action and interaction of pheromone traps for the summerfruit tortrix moth,Adoxophyes orana (F.v.R.)

In a spindle-tree apple orchard, sex pheromone traps for the summerfruit tortrix moth were distributed at different spacings. From the captures, information was derived about influence of prevailing wind direction and of trap spacing on interactions between traps. Prevailing wind direction in the experimental area had no appreciable influence on trap interaction, perhaps because of eddying within the planting. The relationship between density and capture of traps was first considered theoretically and interaction by overlap of active-space areas was distinguished from that by overlap of mere capturing areas, which depend also on distance of dispersal. The actual results were in accordance with these considerations and indicated that the diameter of the active-space areas averaged 15 m. The variation in the captures of the wider-spaced traps was too large to be conclusive about the average width of the capturing areas, but the diameter of these seemed to be more than about 45 m. These data have been related to adequate trap distances for monitoring and mass trapping.Lepidoptera: Tortricidae.     

Bayes Estimation of Reliability for Special k-out-of-m:G Systems

Component lifetimes of a k-out-of-m: G system are s-independent and exponentially distributed. The Bayes-quadratic-loss estimator of reliability for the system is obtained using a conjugate (1-parameter case) or a noninformative (2-parameter case) prior when data are type-II censored. A simple approximation formula for the mean square error of the Bayes estimator is proposed. Based on the mean square-error criterion, the performance of the Bayes estimator under a noninformative prior is compared with that of the maximum likelihood and minimum variance s-unbiased estimators.     

Untersuchung des Kakao-Aromas mit Hilfe der Gaschromatographie

Zusammenfassung Kakao-Aroma wurde mit Hilfe der Destillation unter Hochvakuum an roher Kakaobutter freigemacht. Dieses Aroma wurde mit Hilfe der Gaschromatographie in viele Komponenten getrennt, von danen 12 identifiziert werden konnten     

The effect of wastewater phosphorus removal on shagawa lake, Minnesota: phosphorus supplies, lake phosphorus and chlorophyll a

In early 1973, the phosphorus supply to Shagawa Lake, Minnesota, was reduced by about 80% when a tertiary wastewater treatment plant began operating. Significant reductions in total and soluble reactive phosphorus concentrations have occurred in the lake since that time. By 1976 the average (volume weighted over the entire lake) total and soluble reactive phosphorus concentrations had declined from about 51 and 21 μg l⁻¹ to about 30 and 4.5 μg l⁻¹, respectively, corresponding to 40 and 80% reductions. During 1975 and 1976, chlorophyll a (averaged over the top 5 m) had decreased to less than 50% of the pretreatment level during May-June but during July-August little change had occurred.

A phosphorus residence time model projected equilibrium total phosphorus concentrations of about 12 μg l⁻¹ within 1.5 years. The fact that this level was not reached is attributed to a feedback of phosphorus from the sediments, primarily during summer. This phenomenon has been incorporated into a modified total phosphorus mass balance model which projects the phosphorus pattern through 1976 quite accurately. The close fit of the modified mass balance model implies that the phosphorus supply from the sediments has not diminished since treatment since treatment began, and that further recovery of the lake will depend upon how long this feedback of phosphorus from the sediments continues.     

On-Line Harmonic Analysis as a Diagnostic Design and Control Tool for Power Systems Feeding Arc Furnaces, Thyristor-Controlled Mill Drives, and Power Factor Correction Equipment

Microprocessor-based signal processing equipment for frequencies up to 20 kHz have become compact and fast enough to allow direct on-line real-time analysis on power systems to determine behavior. A case study is presented for a small steelworks operating a 25-MVA open arc furnace, installing 6.5 MVA of thyristor control equipment and further power factor correcting equipment and harmonic filters on a system with ill-defined parameters, low short- circuit capacity, and already containing power factor correcting capacitors tuned at the third harmonic. Discrete spectrum analysis equipment, microprocessor-based and coupled via IEEE-bus to a microcomputer system, was used to do on-line analysis at various points in the system. The high-speed system enabled sophisticated signal processing to yield even and uneven harmonics, stochastic components, system parameters and resonances and mutual interference. It is shown how this is used to rectify problems in the system, adapt equipment, and design power factor and filter equipment.