MINERAL COMPOSITION OF MEDLAR (MESPILUS GERMANICA) FRUIT AT DIFFERENT STAGES OF MATURITY

Abstract The mineral composition of medlar fruit collected (June 15 - October 8) in Turkey at five stages of development was studied. In the fruit, 32 minerals were analyzed and 16 minerals (Al, Ba, Ca, Cu, Co, Fe, K, Li, Mg, Mn, Na, Ni, P, Sr, Ti and Zn) were present at detectable levels. The ripe medlar fruit was richest in potassium (7370 μg/g dry wt), calcium (1780 μg/g dry wt), phosphorus (1080 μg/g dry wt), magnesium (661 μg/g dry wt) and sodium (183 μg/g dry wt). During the fruit development, Al, Ba, Fe, Mn, P, Sr, and Zn were highest in August (unripe fruits) while the concentrations of K, Ca, Mg and Cu gradually decreased throughout development. The ripe medlar fruit is an important source of nutritionally needed minerals and trace elements, in particular Ca, Cu, Fe, K, Mg, Mn, Na and Zn, for human populations in southeastern Europe, Turkey and Iran.     

FORMATION OF TOXIC METHYLHYDRAZINE DURING COOKING OF FALSE MORELS, GYROMITRA ESCULENTA

Methylhydrazine, the main metabolite of N-methyl-N-formylhydra-zones, was detected in the cooking steam of the mushrooms False morels, Gyromitra esculenta. About 25% of the original amount of acetaldehyde-N-methyl-N-formylhydrazone was decomposed during cooking process to methylhydrazine and residues of N-methyl-N-formylhydrazine was detected as well.     

RELEASE OF ENTEROTOXIN A AND THERMONUCLEASE FROM GROWING AND NON-GROWING CELLS OF STAPHYLOCOCCUS AUREUS

Enterotoxin A and thermonuclease were produced by Staphylococcus aureus cell populations in all growth phases. Synthesis of entero-toxin was more rapid than that of thermonuclease early in the exponential phase, whereas later in the exponential phase the thermonuclease synthesis was more rapid than that of enterotoxin. The optimum temperature for enterotoxin production was 42°C, while that for thermonuclease production was in the range 27–33°C. Small amounts of enterotoxin and thermonuclease were released at temperatures up to 45°C.
During heat treatment of staphylococcal cells, enterotoxin production was not observed at temperatures in excess of those permitting growth, although small amounts of thermonuclease were produced. Intracellular enterotoxin was not detected after disintegration of cells under pressure at –30°C. Enterotoxin at detectable concentration, was not bound to the cell membranes. All the results obtained indicate that the synthesis of enterotoxin by S. aureus is intimately associated with cell growth.     

AMELIORATION OF TOXIC EFFECTS OF ETHYLIDENE GYROMITRIN (FALSE MOREL POISON) WITH PYRIDOXINE CHLORIDE

Repeated (five) doses of pyridoxine chloride (vitamin B₆, 10 mg) reduced botht he neurological symptoms caused by ethylidene gyromitrin, the main poisonous compound of the mushroom false morel (Gyromitra esculenta pers. Fr.), and the overall mortality due to ethylidene gyromitrin poisoning in mice treated orally with this poison (400 mg/kg). In contrast, little or no effect was found when the mice were treated with γ-aminobutyric acid (1 mg) or vitamin C (10 mg) after treatment with poison. The significance of these findings is discussed in perspective to possible treatments of human poisonings caused by false morel.     

Different Sensitivities of Whitefish (Coregonus Lavaretus) and Northern Pike (Esox Lucius) Eleutheroembryos to Photoinduced Toxicity of Polycyclic Aromatic Hydrocarbons

The photoinduced toxicity of two polycyclic aromatic hydrocarbons (PAHs), retene (RET) and pyrene (PYR), to the eleutheroembryos of whitefish and northern pike was studied. Fish were exposed to three concentrations of RET and PYR, and irradiated with ultraviolet radiation (UVR) or visible light for 3 h on two consecutive days. UVR covered the absorption maxima of RET and PYR at UVB and UVA, the daily UVR doses were 30 and 28 kJ m^?2, respectively. After 72 h, mortality and behavioral abnormalities were observed. Survivors were analyzed for the proteins of CYP1A, CYP3A, Hsp70, and the activity of glutathione reductase (GR). While neither PAHs nor UVR on their own were lethal, simultaneous exposure caused mortality. The whitefish were more sensitive than the pike to the photoinduced toxicity, and PYR was much more phototoxic than RET. RET induced Hsp70 in both species, and PYR induced GR without UVR in pike.