Effekt von Insulin auf die Keimschlauch-und Myzel-Bildung von Candida albicans: Effect of Insulin on Germ Tube and Mycelial Formation of Candida albicans

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.

Enzymatic and immunological detection of G protein alpha-subunits in the pathogenic fungus Candida albicans

GTP stimulation of adenylyl cyclase from the dimorphic pathogenic fungus Candida albicans is greatly enhanced by preincubation of membrane proteins with cholera toxin, NAD and ATP. In the presence of [32P]NAD the toxin catalyzes the covalent incorporation of radioactivity into a membrane protein of 40 kDa. Pertussis toxin catalyzes the transference of the radioactivity from [32P]NAD to a 32 kDa protein. Two major proteins of 40-42 and 30-32 kDa can also be recognized in Western blots by an anti G alpha-common antibody. The results support the idea that G proteins are part of the hormone sensory transduction chain of Candida [(1990) Biochem. Biophys. Res. Commun. 167, 1177-1183].

Induction of germ-tube formation by Candida albicans in amino acid liquid synthetic medium at 25 degrees C

Candida albicans (3153A) was found to exhibit extensive germ-tube and mycelial development at 25 degrees C when transferred from amino acid synthetic medium at pH 6 to medium of pH 7. Significant germ-tube formation was detectable after approximately 8 h and in all experimental treatments, the peaks of maximal germination occurred at approximately 40-44 h. Such a transition was not only dependent on the initial pH of the medium but also on the glucose concentration and inoculum size. The optimum initial glucose concentration and inoculum size for maximal germ-tube development was 1.25% and 2 X 10(6) cells ml-1 respectively and above or below these values the extent of germ-tube formation was greatly reduced.