Genes affecting the productivity of alpha-amylase in Bacillus subtilis Marburg.

Genetic control of alpha-amylase (alpha-1,4-glucan glucanohydrolase, EC 3.2.1.1.) production by Bacillus subtilis 168 was studied from the standpoint that alpha-amylase production by bacteria is dependent on a long-lived messenger ribonucleic acid and obeys the following equation: E = kappa integral of X-DT where x = cell mass at time t, E = alpha amylase produced, t = culture time, and kappa = productivity constant. So a productivity constand (kappa) is obtained from the slope of the straight line plot of alpha-amylase formed versus the total mass of cells accumulated over that time during the culture process. The following results were obtained. (i) Two sequential mutants, derived from the 168(kappa = 20) strain and having improved alpha-amylase productivity (168 leads to 196), were analyzed for their serine and metal protease production. Strain 128 (kappa = 40) produced half the amount of both proteases, but strain 196 (kappa = 60 similar to 80) produced 20 times that in the original strain. (ii) Amy+ transformants, using the 196 strain as the other three had higher productivity (kappa = 37 similar to 46). These transformants (J71, J47, groups. Seventy-one of 74 Amy+ transformants had a kappa value of 21.0 plus or minus 2.1 and the other three had higher productivity (kappa = 37 similar to 46). These transformants (J71,J47, and J10) produced levels of serine and metal proteases 20 times higher than the other transformants. (iii) Strains 196, J71, J47, and J10 were found to be nonmotile and resistant to phage PBS1, whereas other strains, including strains 168, 128, 3 revertants of strain J71 and 2 revertants of strain 196, were all motile and sensitive to the phage. (iv) Strains 196 and J71 were nonflagellated under electron microscopic observation but strain 168, 128 and a revertant of J71 were flagellated. From the above experimental results, the existence of a quality controlling gene (amyB) was deduced, which is loosely linked to the structural gene and controls productivities of alpha-amylase and proteases, and flagellation. The probable existence of another regulatory gene, amyC, is also discussed.     

Induction of GPR40 positively regulates cell motile and growth activities in breast cancer MCF-7 cells

Abstract

Free fatty acid (FFA) receptors belong to a member of G-protein-coupled receptors. GPCR 120 (GPR120) and GPR40 are identified as FFA receptors and activated via the binding of long- and medium-chain FFAs. The aim of this study was to assess the effects of GPR120 and GPR40 on cell motility and growth in breast cancer cells treated with tamoxifen (TAM). MCF-7 cells were continuously treated with TAM for approximately 6?months. The expression level of GPR40 gene was markedly higher in the long-term TAM treated (MCF-TAM) cells than in MCF-7 cells. In cell motility assay, MCF-TAM cells indicated the high cell motile activity, compared with MCF-7 cells. The cell motile activity of MCF-TAM cells was suppressed by a selective GPR40 antagonist, GW1100. To evaluate the effects of GPR40 on cell growth activity under estrogen-free conditions, cells were maintained in serum-free DMEM without phenol red for 2?days. In estrogen-free conditioned medium, the cell growth rate of MCF-TAM cells was significantly higher than that of MCF-7 cells. In addition, treatment of GW1100 reduced the cell growth rate of MCF-TAM cells. These results suggest that the cell motile and growth activities may be positively regulated through the induction of GPR40 by the long-term TAM treatment in MCF-7 cells.     

Nitrogen and phosphorus fertilization negatively affects strigolactone production and exudation in sorghum

Strigolactones (SLs) are essential host recognition signals for both root parasitic plants and arbuscular mycorrhizal fungi, and SLs or their metabolites function as a novel class of plant hormones regulating shoot and root architecture. Our previous study indicated that nitrogen (N) deficiency as well as phosphorus (P) deficiency in sorghum enhanced root content and exudation of 5-deoxystrigol, one of the major SLs produced by sorghum. In the present study, we examined how N and P fertilization affects SL production and exudation in sorghum plants subjected to short- (5 days) or long-term (10 days) N or P deficiency and demonstrated their common and distinct features. The root contents and exudation of SLs in the N- or P-deficient sorghum plants grown for 6, 12 or 24 h with or without N or P fertilization were quantified by LC–MS/MS. In general, without fertilization, root contents and exudation of SLs stayed at similar levels at 6 and 12 h and then significantly increased at 24 h. The production of SLs responded more quickly to P fertilization than the secretion of SLs, while regulation of SL secretion began earlier after N fertilization. It is suggested that sorghum plants regulate SL production and exudation when they are subjected to nutrient deficiencies depending on the type of nutrient and degree of deficiency.