טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentMaya Reisner
SubjectThe Effect of Cylindrospermopsin from Aphanizomenon
ovalisporum on Several Biochemical Pathways in
Mice
DepartmentDepartment of Biotechnology and Food Engineering
Supervisors Professor Emeritus Cogan Uri
Mr. Werman Moshe
Dr. Assaf Sukenik


Abstract

This resreach was to aimed characterize the influence of cylindrospermopsin, a hepatotoxin produced and excreted by the fresh water nitrogen fixing cyanobacterium Aphanizomenon ovalisporum, under in vitro and in vivo conditions in mice.

Under the in vitro conditions we demonstrated that cylindrospermopsin inhibits the hepatic UMP synthase complex, a major component in nucleotide metabolism, which synthesizes UMP from orotic acid.

Physiological responses of mice to sub-lethal doses of cylindrospermopsin, provided via the drinking water, were characterized during short and long term exposure periods using ICR mice. In the short term system, purified cylindrospermopsin, at 0.64 mg/L, was administered to male mice for a period of three weeks. In the long term system, cylindrospermopsin-containing cyanobacterial extract of Aphanizomenon ovalisporum, at 0.065-0.65 mg/L, was administered to male and female mice, for periods of 20 and 44 weeks.

The presence of cylindrospermopsin in the drinking water of mice was found to influence the relative weights of liver, kidney and testes. Levels of orotic acid in the urine of the exposed mice were higher than that of the controls. The morphology of the red blood cells was changed, a phenomenon known as acanthocytosis. Acanthocyte formation followed an increase in the cholesterol to phospholipids ratio in the red blood cell membrane. In addition, cylindrospermopsin inflicted an increase in plasma and a decrease in liver cholesterol levels, respectively.

Our results clearly demonstrate the need to determine guidelines regarding the consumption of fresh water containing cylindrospermopsin.