The Reaction of Reducing Sugars with Histones

The e-amino groups of histone proteins were eliminated by condensation with glucose, fractose or mannose. The trichloroacetic acid extracted, DNA negative nuclei treated with reducing sugars, stained easily with basic dyes.     

The Relation between the Rate of Nutrient Uptake by Excised Barley Roots and their Content of Sucrose and Reducing Sugars

A re-examination of the results of previous experiments hasshown that the positive regression of the rate of nutrient uptakeby excised barley roots on sugar content is attributable tothe reducing sugar fraction. Partial regression coefficientsof the rates of uptake of potassium, nitrogen, and phosphoruson reducing sugar content were all positive; those on sucrosecontent were either not significant or negative. These results were confirmed for potassium by experiments inwhich the sugar content of the roots was varied by varying thenitrogen supply to the plants from which the roots were taken,by shading them or by supplying sucrose to the solution in whichthe excised roots were held.     

The Uptake of Sugars by Chara corallina

The influx of several monosaccharides into Chara corallina wasstudied under varying conditions of temperature, in the presenceof inhibitors, and by the use of competition experiments. Itwas found that the mechanism of transport was stereospecific,and the complex interactions between the sugars were characteristicof a carrier-mediated system. There is reason to believe thatthe carrier involved in this system has a narrower range ofaffinities than is usually attributed to a sugar carrier, forglucose and fructose appear to have different sites of entry,though each can influence the uptake of the other. In additionthe carrier system is situated in the plasmalemma and maintainedby metabolic energy.     

Kendall's and Spearman's correlation coefficients in the presence of a blocking variable

The use of a weighted sum of Kendall's taus or a weighted sum of Spearman's rhos for testing association in the presence of a blocking variable is discussed. In a Monte Carlo study the two are shown to have essentially the same power with the optimal choice of weights. In the presence of ties, the weighted sum of Spearman's rhos is preferred because its variance has a much simpler form. An example is given from the field of radiation therapy.     

Pectinase Activity Determination: An Early Deceleration in the Release of Reducing Sugars Throws a Spanner in the Works!

Recently, it has been suggested that pectinases could be used to hydrolyze pectin in biorefineries based on pectin-rich agro-industrial wastes. However, for this to be viable, the cost of their production would need to be lowered significantly. In fact, over the last few decades, there have been many attempts to improve pectinase production by existing strains or to screen for new strains from environmental isolates. In these studies, it is necessary to measure pectinase activities. Many researchers use single-time-point assays that involve incubation of pectinolytic extracts with pectic substrates for a fixed time, followed by determination of the liberated reducing sugars. However, different researchers use quite different conditions for this assay. Furthermore, no attention has been given to the reaction profile during the assay. In the current work, we show, for the first time, that a significant deceleration of the rate of liberation of reducing sugars occurs over the first ten minutes of the reaction. As a consequence, the incubation time used in a single-time-point assay has a large effect on the value obtained for the activity. In fact, we demonstrate that, depending on the particular combination of incubation time, pectin concentration and reaction temperature, the same extract could be reported to have activities that differ by an order of magnitude. In addition, we show that the relative activities obtained with polygalacturonic acid do not correlate with those obtained with pectin. We conclude that it is currently impossible to make meaningful comparisons between pectinase activities reported in the literature by workers who have used different assay conditions. Therefore there is an urgent need for the development of a standardized assay for evaluating the saccharification potential of pectinase complexes.     

The Relative Power of Two Asymptotic Multivariate Tests for Homogeneity in a Contingency Table

In a three way contingency table two multivariate tests for homogeneity have been proposed by the author (1983) a the “catanova” test, which is a trace “metric” test and b the “multinova” test which is determinant based. Both tests are asymptotically distributed as chi-square. In this paper, the power values of the tests are compared and conditions are given for preference of each test.     

Dark and Photometabolism of Sugars by a Blue Green Alga: Tolypothrix tenuis

The carbohydrate metabolism of the autotrophically grown blue-green alga, Tolypothrix tenuis, was studied. The alga respires glucose, fructose, galactose, and ribose.     

Estimation of the Power of the Kruskal-Wallis Test

Power calculations of a statistical test require that the underlying population distribution(s) be completely specified. Statisticians, in practice, may not have complete knowledge of the entire nature of the underlying distribution(s) and are at a loss for calculating the exact power of the test. In such cases, an estimate of the power would provide a suitable substitute. In this paper, we are interested in estimating the power of the Kruskal-Wallis one-way analysis of variance by ranks test for a location shift. We investigated an extension of a data-based power estimation method presented by Collings and Hamilton (1988), which requires no prior knowledge of the underlying population distributions other than necessary to perform the Kruskal-Wallis test for a location shift. This method utilizes bootstrapping techniques to produce a power estimate based on the empirical cumulative distribution functions of the sample data. We performed a simulation study of the extended power estimator under the conditions of k = 3 and k = 5 samples of equal sizes m = 10 and m = 20, with four underlying continuous distributions that possessed various location configurations. Our simulation study demonstates that the Extended Average × & Y power estimation method is a reliable estimator of the power of the Kruskal-Wallis test for k = 3 samples, and a more conservative to a mild overestimator of the true power for k = 5 samples.