Industrial yeast strain improvement: construction of strains having the killer character and capable of utilizing starch

Summary A hybrid of Saccharomyces cerevisiae with the ability to utilize starch and to produce the killer toxin was constructed by the protoplast fusion technique. The hybrid was obtained in two steps. In the first, a wild killer strain was fused with a laboratory strain (S. cerevisiae STA2). A fusion product which carried the killer factor and the ability to grow on starch was selected. In the second step, this hybrid was fused with a baker's yeast.     

Effluent treatment by anAzotobacter sp.

Summary The effect of pH, temperature and carbon source on the specific growth rate of anAzobacter sp. was studied in nitrogen-deficient media. The optimum pH and temperature were 7.0 and 30°C respectively, with COD removal 27–85%. The strain was also used for treating effluents of a pharmaceutical industry, with 37–45% COD removal.     

Isolation of yeast with killer activity and its breeding with an industrial baking strain by protoplast fusion

Summary Wild strains of Saccharomyces cerevisiae were isolated from dairy products, bakery goods, fresh fruit and vegetables, and tested for killer activity. Four isolates out of 238 strains possessed killer activity. The best of these was converted to the petite form and hybridized with an industrial strain of Saccharomyces cerevisiae by protoplast fusion. Thirty-eight out of 104 isolates had killer activity, and some of these had good dough-raising activity as well.     

The influence of auxins,light and cell differentiation on solasodine production bySolanum eleagnifolium Cav. calli

The effect of auxins, light and cellular production ofSolanum eleagnifolium Cav. calli were studied. 2,4-dichlorophenoxyacetic acid (4.5 M) was the plant growth regulator used for calli initiation and this produced the highest solasodine concentration. The solasodine concentration in darkness was significantly lower than that achieved under a photoperiod of 16 h. Differentiated tissue obtained by adequate hormonal balance (several ratios of 3-indolebutyric acid to 6-benzylaminopurine) produced higher yields of solasodine than non-differentiated tissue. 3-indolebutyric acid (2.5 M) and 6-benzylaminopurine (8.8 M) increased the productivity of solasodine by 100%.Abbreviations BAP 6-benzylaminopurine - KIN Kinetin - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA 3-indoleacetic acid - NAA 1-naphtaleneacetic acid - IBA 3-indolebutyric acid - 2,4,5-T 2,4,5-trichlorophenoxyacetic acid - DW dry weight - GI      

Advantages and limitations in the use of hairy root cultures for the production of tropane alkaloids: Use of anti-auxins in the maintenance of normal root morphology

Summary Brugmansia candida hairy roots, obtained by infection withAgrobacterium rhizogenes LBA 9402, exhibit, after subculturing in liquid media, a tendency towards dedifferentiation. It has been found that the following strategies can be applied to inhibit this dedifferentiation and preserve normal root morphology: (a) lowering both the mineral and sucrose concentration in the media employed so as to diminish osmotic stress (a condition to which these roots appear to be particularly susceptible); (b) employing antiauxins in appropriate concentrations; and (c) maintaining the hairy roots on solid media prior to use in production processes in liquid media. The first strategy suggested does not favor alkaloid productivity, but in this case a two-step method could be attempted: biomass with normal root morphology could be obtained in a first stage using low sucrose concentrations, and in a second stage, sucrose could be increased in order to achieve higher productivity. In all the clones ofB. candida obtained, alkaloid production was biased towards scopolamine.     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Effect of Metalaxyl on the incidence and severity of Pearl millet downy mildew disease in Northern Nigeria

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.     

Synergistic effect of methyl jasmonate and cyclodextrins on anthraquinone accumulation in cell suspension cultures of Morinda citrifolia and Rubia tinctorum

Plant in vitro culture is a platform for producing secondary metabolites that combines safety, quality and low environmental impact. Besides, it is possible to increase the accumulation of these compounds by different strategies, such as elicitation. In this work, we analyzed the effects of the combination of methyl jasmonate (MeJ) and two cyclodextrins (CDs) on the production of anthraquinones (AQs) in cell cultures of Rubiaceae (Morinda citrifolia and Rubia tinctorum). These secondary metabolites have been traditionally used as dyes and have interesting therapeutic applications. The experiments were designed according to a full factorial design of two factors (MeJ and a CD) in two levels (0 and 0.1 mM for MeJ, and 0 and 20 mM of the CD). MeJ and (2-hydroxypropyl)-β-cyclodextrin (HPCD) synergistically increased intracellular AQ content in suspension cultures of R. tinctorum, and, to a lesser extent, in suspension cultures of M. citrifolia. Combination of MeJ with another CD, 2-methyl-β-cyclodextrin, led to a more intense and later increase in AQ content in cell cultures of R. tinctorum when compared to MeJ–HPCD treatment. However, the combination of CD and MeJ failed to induce a drastic AQ release to the culture media. Nevertheless, our results show that combination of strategies (using a CD and MeJ) was successful to increase secondary metabolite accumulation in suspension cultures. To our knowledge, this is the first report of synergistic effect of MeJ and CD on AQ accumulation in plant in vitro cultures.