[A statistical method for the determination of the yield correlation of antibiotic-producing microorganisms].
The antibiotic yields of industrial selectants must be checked at several steps of cultivation. Here the question arises whether the activities at the different levels of cultivation are correlated. The common coefficient of correlation cannot be used because repeated determinations of the yield at one selectant result in different values. In order to have only one fixed value per selectant we define the mean value around which the observed values are varying. But these mean values cannot be observed. Thus, an adequate method of correlation similar to that in Guiard and Herrendörfer (1977) was used. The method is demonstrated in two examples: With selectants of Streptomyces noursei for streptothricin titers in 20 ml- and 20 l-cultures as well as with selectants of Penicillium chrysogenum for potency indices in surface cultures and penicillin titers in 50 ml submerged cultures, respectively. In both cases the coefficients of correlation were above 0.7.
A method for selection of antibiotic producing strains of Penicillium chrysogenum on solid media by means of microcup cultivation and image analyzing of inhibition zones
Abstract The paper describes a method for proper estimation of differences of antibiotic yields produced by selectants of Penicillium chrysogenum on solid media. The reliability of the technique was proved by the use of different mutants isolated after treatment with NTG. By the aid of an inoculator, spores of each strain were transferred onto agar surfaces of so-called microcups which all possessed open bottoms for the determination of antibiotic content by bioassay. These were small cylindrical vessels of polypropylene containing one ml of solid agar medium similar in its composition to fermentation broth. After sufficient incubation, the developed microcultures were stored at 4–6°C for at least 24 h before they were set up on bioassay plates. This procedure permitted equilibration of antibiotic concentration within the cylindrical agar piecces. This was absolutely necessary in order to reproduce the characteristic distinctions between the proved selectants. The yields were then estimated by measuring the areas of the inhibition zones with an image analyzing system (Quantimet 720 M, controlled by a PDP 11 computer). In contrast to microcultures that had not been cooled after growth, the statistical comparison of repeated experiments, calculated by a new method (Horn, M., Bormann, E.J., Harnish, M. (1984), Ein statistisches Verfahren zur Ermittlung der Leistungs-Korrelation antibiotikabildender Mikroorganismen im Labor- und Tecknikumsmaβstab. Allg. Mikrobiol. 24, 7, 443–449), delivered a very good correlation.
A Study on Technology Embedded English Classes Using QR Codes
The development of information and technology has brought plenty of changes to the educational environment. The prevalence of smart phones is particularly playing a huge role in shaping learning methods. Smart phones provide the opportunity to scan QR codes, which can greatly ease access to information. Due to a high recognition speed, recognition rate, and restoration rate, they can be useful tools for English teachers to use in their class. In this study, we suggest using QR codes for writing and picture descriptions. Based on this study, more research should invest in Technology Embedded English teaching models to create better English classes for students.