| Abstract: | Resumen y conclusiones Se observa la diferencia entre las variables productoras y no productoras de riboflavina, establecidas por sus caracteres morfológicos y microscópicos, y se estudia la influencia de ciertos factores y la inmunidad de otros sobre las mismas.Observaciones microscópicas muestran a las variables flavinogénicas de fácil y rápida esporulación.Factores físicos como la luz, la temperatura, el calor, la radiación ultravioleta, no determinan alteraciones digunas de mención. Las cepas flavinogénicas pueden perder esa propiedad, por cercanía de contaminantes, contacto con substancias químicas, etc.Antibióticos y quimioterápicos no ejercen acción sobre ninguna de las formas deEremothecium. Las sulfas actuan levemente sobre la forma blanca menos que sobre la anaranjada.Factores nutricios como el extracto de papa, el almidón y la peptona estimulan la flavinogénesis, por lo que se considera que agregadas en las proporciones establecidas al Sabouraud común, se mejorará el medio de cultivo y se obtendrán cepas de mayor rendimiento.Cepas altamente flavinogénicas se obtienen por desarrollo en medios conteniendo extracto de tierra; por exposición de la cepa a la radiación ultravioleta en estado de hibernación; por pasaje por caldos peptonados y por desarrollo en medios conteniendo riboflavina.Se observa que efectuando los transplantes cada cuatro dias disminuye el porcentaje de variables blancas. Por crecimiento en medios conteniendo riboflavina, se induce a las formas blancas a la producción de vitamina.Finalmente aconsejamos como medio de mantenimiento el uso de Sabouraud al que se agrega riboflavina en niveles no superiores 1 mg/ml y efectuar los repiques cada cuatro dias.
Summary The property ofEremothecium ashbyii to produce riboflavin is exploited for the industrial production of the vitamin. However, the fungus presents natural variability giving rise to several variants such as the orange one with a high level of riboflavin production, the yellow one with less productive capacity and the white one without flavinogenic properties. This problem is interesting from a biological and industrial point of view.The purpose of the present work was to detect possible differences between the two extreme variants ofEremothecium ashbyii (orange or strong producer of riboflavin and white or non producer form) so as to stimulate riboflavin production in the white strain and on the other hand, to stabilize the flavinic ones. To achieve this, the influence of different factors on the two selected variants was tested with the following results:Macroscopic observations showed morphological differences in the aspect of both variants and in the production of riboflavin.Microscopic observations showed that the flavinic strain sporulated rapidly whereas the white strain did so more slowly. Moreover, a relation was shown to exist between sporulation and riboflavin production.Physical factors such as light, temperature, heat and ultraviolet radiation did not determine appreciable alterations in the two forms studied. Antibiotics and chemotherapics did not excercise any action on either of the variants. The sulfamides had a slightly greater affect on the orange form than on the white one. Nutrient factors such as potato extract, starch and peptone stimulate flavinogenesis, and for that reason, it was considered that if added, in the established proportions to the Sabouraud medium they would improve the culture medium.Highly flavinogenic strains were obtained by development in a medium with earth extract, by exposure of the strain to ultraviolet radiation when it was in the hibernation state, by passage through peptoned broth and by development in a culture medium to which riboflavin had been added. The flavinic strains may lose its producing property due to the presence of contaminants, through contact with chemical substances etc.It was observed that by making transplants every four days and not weekly, the percentage of the white forms decreased. When the white form was developed in a culture medium with riboflavin, vitamin production was induced.Finally, it is suggested that Sabouraud's medium with the addition of 1 mg/ml riboflavin would be an adequate maintenance medium and that making transplants every four days, it would be possible to obtain a greater percentage of riboflavin producing strains.
Trabajo realizado en el Instituto de Industrias Bioquímico Farmacéutico, Facultad de Farmacia y Bioquímica de la Universidad de Buenos Aires. |
