Interrelationship of carbohydrate metabolism and alkaline phosphatase synthesis in Bacillus licheniformis 749/c

Activity of hydrolytic enzymes in fungi isolated from diabetic pregnant women: is there any relationship between fungal alkaline and acid phosphatase activity and glycemic control?

Ability to respond to environmental changes and secretion of hydrolases are considered to be important for Candida virulence. In this study we determined and compared the activities of 19 different hydrolases of the fungal strains isolated from diabetic and non-diabetic pregnant women. We also looked for the presence of a relationship between hydrolase activities and glycemic control, and, furthermore, evaluated the influence of gestational age on the activity of hydrolases. Mycological examinations were performed for 119 diabetic pregnant women: 47 with diabetes mellitus type I (DM), 72 with gestational diabetes (GDM), and for 132 healthy women (CON). Samples were collected from the vagina, rectum and oral cavity and cultured on Sabouraud media. The fungal hydrolase activities were evaluated using the API ZYM test (bioMerieux). For the 19 different fungal hydrolases tested, 13 activities were present in the isolated fungal strains. The activity of alkaline phosphatase (ALP) in vaginal strains (p=0.028) and acid phosphatase (ACP) in strains from the vagina (p=0.006) and rectum (p=0.049) was significantly lower in DM than in GDM and CON women. In conclusion, we describe for the first time that fungi isolated from pregnant diabetic women have lower activity of both phosphatases compared to fungi isolated from healthy women. Furthermore, similar differences of mean ALP and ACP activities were observed in the course of pregnancy in strains from the vagina and rectum of DM and CON women. However, strains from DM had lower activity at each stage of pregnancy. The highest activity of ALP and ACP was detected at the beginning, then declined, and had the lowest values between the 24(th) and 33(rd) week of gestation. After that period the activity of both phosphatases increased.

Cellular biosensing system for discovery of protein synthesis inhibitors with an electrochemical phosphate modulator to regulate the acid phosphatase gene expression of Saccharomyces cerevisiae

A cellular biosensing system for screening protein synthesis inhibitors has been developed by linking an electrochemical phosphate modulator and matrix-immobilized yeast cells with an optical sensing device. To screen the protein synthesis inhibitors, yeast phosphatase gene regulating system has been employed by linking an electrochemical phosphate modulator. Since the yeast phosphatase gene coding gammaAPase is expressed, when the phosphate concentration in solution is lowered below the threshold, the gammaAPase production is triggered by lowering the phosphate concentration with the electrochemical phosphate modulator, and monitored continuously with the photometric device. The electrochemical phosphate modulator was assembled with matrix-immobilized yeast cells. The module could insert to ordinal cuvette to monitor the induced gammaAPase activity in an ordinal photometer. Using the system, induction profile of protein synthesis was easily observed and was affected remarkably by various protein synthesis inhibitors. This seems promising that the system can be applied for first screening process of de novo protein inhibitors. The cellular biosensing system seems promising in screening protein synthesis inhibitors.

Alkaline phosphatase production during sporulation of Bacillus cereus

Cell-bound alkaline phosphatase of Bacillus cereus was produced during vegetative growth and sporulation in a complex medium. Addition of glucose repressed the sporulation process and the amount of enzyme synthesized increased. The time course of alkaline phosphatase production is very similar in both sporulating and non-sporulating cells. Irrespective of sporulation, alkaline phosphatase level shows a peak of activity in the exponential phase, and another in the stationary phase of growth. This preliminary data indicates differences between B. cereus, and B. subtilis in alkaline phosphatase characteristics.

Cloning of the crystalline cell wall protein gene of Bacillus licheniformis NM 105

A protein with a tetragonal pattern, defined as RS protein, was found on the wall surface of an alkaline phosphatase secretion-deficient mutant (NM 105) of Bacillus licheniformis 749/C. The protein was present on the wall surface of the exponential-growth-phase cells, but at the stationary growth phase it was overproduced and hypersecreted. This protein was precipitated to homogeneity from the culture fluid by 80% ammonium sulfate saturation and chilled acetone. The molecular mass of the protein was 98 kilodaltons, and it had a single subunit in a sodium dodecyl sulfate gel. Specific anti-RS antibody was generated in rabbits and used to immunolabel the RS protein on the cells at different growth phases. In early-exponential-growth-phase cells, the outside surface of the wall, the cytoplasm, and the inside surface of the cytoplasmic membrane were labeled. In stationary-growth-phase cells, the cytoplasm was poorly labeled, but the labeling on the outside surface of the wall was high. AB. licheniformis NM 105 gene library was made by using the lambda phage EMBL3. The RS protein expression from this gene library was detected by a modified autoradiographic procedure. One of the amplified RS protein-positive plaques (4213-1) containing recombinant DNA was chosen, and the restriction map of this DNA was prepared. The RS protein expressed in Escherichia coli NM 539 infected with 4213-1 recombinant phage had a lower molecular mass than the purified authentic RS protein. The 4.5-kilobase-pair (kbp) SalI-EcoRI fragment of the recombinant DNA was cloned in the shuttle plasmid pMK4 to construct pMK462, which was expressed in B. subtilis MI112 and produced the RS protein identical in molecular mass to the purified authentic RS protein. The RS protein expression was also demonstrated in cryosections of transformed E. coli and B. subtilis cells by immunoelectron microscopy. The 1.2-kbp SalI-HindIII and 1.8-kbp HindIII-HindIII recombinant DNA restriction enzyme fragments, respectively, from the right of the restriction map produced anti-RS antibody cross-reacting proteins. The expression of the 1.2-kbp SalI-HindIII DNA fragment cloned in pUC8 could be induced with isopropyl-beta-D-thiogalactopyranoside. The 1.8-kbp DNA restriction fragment hybridized with both the chromosomal DNA of strain NM 105 and the recombinant phage 4213-1 DNA. The RS gene expression was finally demonstrated in transformed E. coli 539 cells by in situ hybridization of frozen thin sections with the 1.8-kbp HindIII biotin-dATP probe and immunolabeling these with anti-biotin immunoglobulin G and protein A-gold.

Alkaline phosphatase secretion-negative mutant of Bacillus licheniformis 749/C

An alkaline phosphatase secretion-blocked mutant of Bacillus licheniformis 749/C was isolated. This mutant had defects in the phoP and phoR regions of the chromosome. The selection procedure was based on the rationale that N-methyl-N'-nitro-N-nitrosoguanidine can induce mutations of closely linked multiple genes. The malate gene and the phoP and phoR genes are located at the 260-min position in the Bacillus subtilis chromosome; hence, the malate gene could be used as a marker for the mutation of the phoP and phoR regions of the chromosome. In a two-step selection procedure, strains defective in malate utilization were first selected with the cephalosporin C procedure. Second, these malate-defective strains were further screened in a dye medium to select strains with defects in alkaline phosphatase secretion. One stable mutant (B. licheniformis 749/cNM 105) had a total secretion block for alkaline phosphatase and had the following additional characteristics: (i) the amount of alkaline phosphatase synthesized was comparable to that in the wild type; (ii) the alkaline phosphatase was membrane bound; (iii) the mutant strain alkaline phosphatase, in contrast to that of the wild type, could not be extracted with MgCl2, although the amounts of protein extracted from each strain were comparable; (iv) the sodium dodecyl sulfate-polyacrylamide gel pattern of MgCl2-extracted proteins from the mutant strain was different from that of the wild-type proteins; (v) the mutant, unlike the wild type, could not use malate as a sole source of carbon; and (vi) the outside surface of the wall of the mutant cells contained an additional electron-dense layer that was not present on the wild-type cell wall surface.

Effect of cobalt on synthesis and activation of Bacillus licheniformis alkaline phosphatase

The effect of CO2+ on the synthesis and activation of Bacillus licheniformis MC14 alkaline phosphatase has been shown by the development of a defined minimal salts medium in which this organism produces 35 times more (assayable) alkaline phosphatase than when grown in a low-phosphate complex medium or in the defined medium without cobalt. Stimulation of enzyme activity with cobalt is dependent on a low phosphate concentration in the medium (below 0.075 mM) and continued protein synthesis. Cobalt stimulation resulted in alkaline phosphate production being a major portion of total protein synthesized during late-logarithmic and early-stationary-phase culture growth. Cells cultured in the defined medium minus cobalt, or purified enzyme partially inactivated with a chelating agent, showed a 2.5-fold increase in activity when assayed in the presence of cobalt. Atomic spectral analysis indicated the presence of 3.65 +/- 0.45 g-atoms of cobalt associated with each mole of purified active alkaline phosphatase. A biochemical localization as a function of culture age in this medium showed that alkaline phosphatase was associated with the cytoplasmic membrane and was also found as a soluble enzyme in the periplasmic region and secreted into the growth medium.