A simplified routine method for determining carbohydrate fermentation by yeasts

The use of commercially available materials in a minimal medium contributes to the simplicity, reliability, and reproducibility of a method described to demonstrate carbohydrate fermentation reactions by yeasts. The medium consists of 1% yeast extract and 2% test carbohydrate in distilled water, dispensed in a modified Durham fermentation tube. Carbohydrate fermentation patterns can usually be obtained within a period of 7 days. The ability of yeasts to ferment carbohydrates is determined strictly on the basis of gas production from the substrate. The method proved reliable in reproducing established fermentation patterns for 112 different yeast strains representing 13 separate genera.

---

Zusammenfassung Der Gebrauch von handelsüblichen Grundbestandteilen in einem geringen Medium trägt zu der Einfachheit, Zuverlässigkeit und Reproduzierbarkeit der beschriebenen Methode, um die Gärungsreaktionen der Karbohydrate durch Hefen zu veranschaulichen, bei. Das Medium besteht aus einem 1 prozent. Hefenauszug und aus einem 2 prozentigen Testkarbohydrat in destilliertem Wasser, die auf modifiziertes Durham Gärungsreagensglas verteilt sind. Das Karbohydrat-Gärungsmodell kann gewöhnlich innerhalb einer Periode von sieben Tagen erhalten werden. Die Fähigkeit von Hefen, Karbohydrate zu vergären, ist ausschließlich auf Grund der Gasentwicklung aus den Produkten bestimmt. Die Methode erwies sich zuverlässig in der Erzeugung festgestellter Gärungsmodelle aus 112 Hefen, die 13 verschiedene Gattungen darstellten.

     

A simplified method of rapid hemagglutination test for determining the levels of tetanus antibodies]

A new, simplified methodology of preparation of lyophilized chrome-coated turkey blood cells (formalin-treated ) for rapid identification of tetanus antibodies in indirect hemagglutination test is described. Blood cells diagnostic preparations obtained in this way were easier and three times faster to prepare than tanned cell preparations . They maintained unchanged capability for specific agglutination during at least one year of storage when kept at 4 degrees C. proposed methodology enable to start a production of laboratory kits necessary for controlled prophylaxis of tetanus.     

A simplified electrophoretic system for determining molecular weights of proteins.

Electrophoresis of 31 different proteins in commercially prepared polyacrylamide gradient gels, Gradipore, yields a linear relationship between a hypothetical limiting pore size (the reciprocal of a limiting gel concentration, GL) and the cube root of the mol.wt., over the range 13 500-9000 000. A regression analysis of these data reveals that 98.6% of all variability in 1/GL is explained by the molecular weight, and this degree of accuracy compares favourably with existing methods for the determination of molecular weight by retardation of mobility in polyacrylamide. This new procedure has the additional advantages that molecular-weight standards can be obtained from readily available body fluids or tissue extracts by localizing enzymes and other proteins by standard histochemical methods, and that the same electrophoretic system can be used in determining molecular weights as is used in routine surveys of populations for individual and species variation in protein heterogeneity.     

A simplified variant of the Maxam-Gilbert method for determining the primary structure of oligonucleotides and DNA fragments

A modification to the Maxam-Gilbert method is proposed that involves precipitation of the nucleotide material with the acetone solution of lithium perchlorate after the completion of chemical reactions to remove the reagents. Modification of cytosine residues is carried out in the presence of lithium chloride. The new mode of precipitation simplifies and speeds up the analysis of oligonucleotides and DNA fragments.     

A method for determining the P/R ratio in running waters

A method is described for determining the relationship between primary production and respiration (P/R) in rapidly flowing waters. The Bliznec, Medveak and ernomerec Brooks near Zagreb-Jugoslavia, were taken as examples. The method evolved is based on the determination of oxygen at equally spaced time intervals during day and night (Table 1).Finally the formula % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaciaacaqabeaadaqaaqaaaOqaamaalaaabaGaai% ikaiaadseadaWgaaWcbaGaaGOmaaqabaGccqGHsislcaWGebWaaSba% aSqaaiaaigdaaeqaaOGaaiykaiabgUcaRiaacIcacaWGobWaaSbaaS% qaaiaaigdaaeqaaOGaeyOeI0IaamOtamaaBaaaleaacaaIYaaabeaa% kiaacMcacqGHRaWkcaGGOaGaeuiLdqKaamizaiabgkHiTiabfs5aej% aad6gacaGGPaaabaGaamOtamaaBaaaleaacaaIXaaabeaakiabgkHi% Tiaad6eadaWgaaWcbaGaaGOmaaqabaGccqGHsislcqqHuoarcaWGUb% aaaaaa!5366!\[\frac{{(D_2 - D_1 ) + (N_1 - N_2 ) + (\Delta d - \Delta n)}}{{N_1 - N_2 - \Delta n}}\]% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaciaacaqabeaadaqaaqaaaOqaaiaadcfacaGGVa% GaamOuaiabg2da9aaa!3AC3!\[P/R = \].is mentioned, where D₁ denotes the average oxygen amount measured in the morning at the onset of the photosynthetic activity, D₂ the average oxygen amount at the end of the photosynthetic activity, N₁ the average oxygen deficiency at the beginning and at the end of dark period.For the purpose of checking, the values of saprobity determined after Zelinka & Marvan's method in a direct ecological way, in the same brook sections, are compared with the P/R values obtained (Table 2).Institute for Botany, University of Zagreb     

A simplified noninvasive method to measure airway blood flow in humans.

Our laboratory has previously developed and validated a noninvasive soluble gas uptake method to measure airway blood flow (Qaw) in humans (Onorato DJ, Demirozu MC, Breitenbücher A, Atkins ND, Chediak AD, and Wanner A. Am J Respir Crit Care Med 149: 1132-1137, 1994; Scuri M, McCaskill V, Chediak AD, Abraham WM, and Wanner A. J Appl Physiol 79: 1386-1390, 1995). The method has the disadvantage of requiring eight breath-hold maneuvers for a single Qaw measurement, a complicated data analysis, and the inhalation of a potentially explosive gas mixture containing dimethylether (DME) and O2. Because of these shortcomings, the method thus far has not been used in other laboratories. We now simplified the method by having the subjects inhale 500 ml of a 10% DME-90% N2 gas mixture to fill the anatomical dead space, followed by a 5- or 15-s breath hold, and measuring the instantaneous DME and N2 concentrations and volume at the airway opening during the subsequent exhalation. From the difference in DME concentration in phase 1 of the expired N2 wash-in curve multiplied by the phase 1 dead space volume and divided by the mean DME concentration and the solubility coefficient for DME in tissue, Qaw can be calculated by using Fick's equation. We compared the new method to the validated old method in 10 healthy subjects and found mean +/- SE Qaw values of 34.6 +/- 2.3 and 34.6 +/- 2.8 microl.min(-1).ml(-1), respectively (r = 0.93; upper and lower 95% confidence limit +2.48 and -2.47). Using the new method, the mean coefficient of variation for two consecutive measurements was 4.4% (range 0-10.4%); inhalation of 1.2 mg albuterol caused a 53 +/- 14% increase in Qaw (P = 0.02) and inhalation of 2.4 mg methoxamine caused a 32 +/- 7% decrease in Qaw (P = 0.07). We conclude that the new method provides reliable values of and detects the expected changes in Qaw with vasoactive drugs. The simplicity and improved safety of the method should improve its acceptability for the noninvasive assessment of Qaw in clinical research.     

P50 values determined by tonometry and by simplified techniques

Actual determination of the position of the oxygen hemoglobin dissociation curve (P50) was compared to three methods of estimating P50 in 39 patients with various diseases. There was a significant correlation between determined and estimated P50 values (P less than 0,001) for each of the methods studied. The data suggest that calculating P50 is reliable and may replace the need for actual measurement.     

Computer-assisted method for multi-exponential curve fitting for determining cerebral blood flow.

A computer program has been developed for use in determining cerebral blood flow using an inert radioactive gas. The basic algorithm involves the determination of multiple exponential coefficients from the complex concentration-time function. The exponential coefficients are determined by 'peeling' away slower exponentials complex function one at a time. The procedure involves the use of a small laboratory computer in the interactive graphics mode. The method is currently in use analyzing data in a cerebral vascular research laboratory.