Egg transport in ovariectomized rabbits as affected by different combinations of oestrogen and progesterone.

A total of 1548 eggs was transferred to the oviducts of rabbits ovariectomized 45 days to 7 months earlier. The pattern of egg transport was disrupted, and the majority of eggs were in the vagina 60-72 h after transfer. To determine the role of the ovarian hormones on egg transport, the effects of various combinations of oestrogen and progesterone were studied. None of the hormonal treatments produced the normal transport pattern and large proportions of transferred eggs were retained in the oviducts. It is concluded that as long as progesterone is the dominant hormone, eggs move very slowly through the isthmus, and that a surge of oestrogen is required to modify the action of progesterone and to speed the movement of eggs to the uterus.

Production of penitrem A by Penicillium crustosum isolated from foodstuffs.

Sixty one isolates of Penicillium crustosum originating from various foodstuffs were screened for penitrem A production by thin-layer chromatography. The highest producers of penitrem A (4 isolates) were grown in various liquid media. Skimmed milk (2%)/potato extract (2%)/sucrose (2%) (SPS) medium supported the highest toxin production and P. crustosum Sp 1552 was selected as the best producer of penitrem A. Optimal conditions for the production of penitrem A were to grow the isolate Sp 1552 (stationary) in 100 ml of SPS medium (with 4% sucrose) in 500-ml flasks for 3 weeks at 25 degrees C with initial pH 5.7. The isolation and purification of penitrem A is described. Approximately 246 mg of pure penitrem A was obtained from 200 flasks each containing 100 ml of SPS medium.

Stability of citrinin and deoxynivalenol during germination process of barley.

The stability of citrinin and deoxynivalenol during germination process of barley spiked with these mycotoxins at a level of 2/ig/g was investigated. Germinated barley was analyzed after 1, 3, and 5 days to follow the stability of citrinin and deoxynivalenol during the germination process. Two thin layer chromatographic methods were used for determinations of citrinin and deoxynivalenol. An average of 93.6% of citrinin and 77.1% of deoxynivalenol were destroyed within 5 days during the germination process of barley.

The degenerative effect on rabbit implantation sites by indomethacin. I. Timing of indomethacin action, possible effect on uterine proteins and the effect of replacement doses of PGF2 alpha.

To determine the effective time of indomethacin (Id) action in disrupting early pregnancy, groups of rabbits were treated at various stages after mating with Id and/or replacement doses of PGF2 alpha. Effect of Id on the secretion of uterine proteins was also investigated. The highest rate of embryonic death occurred when Id was injected twice daily during days 5-7 of pregnancy, and days 5-6 appear to be the most critical. Persisting levels of Id during this critical stage is required to induce the antifertility effect. The results also indicate that the adverse effect of Id is not mediated through an effect on uterine proteins, and is mainly due to the inhibition of PG's synthesis. PG's are apparently required for normal implantation and early development.

Treatment with prostaglandins reduces the antifertility effect of indomethacin in rabbits.

Indomethacin (Id) treatment of rabbits at the time of implantation resulted in a significant reduction in the number of viable embryos as well as significant reduction in plasma progesterone concentrations. Treatment with a mixture of prostaglandins (PGs) together with Id caused a significant increase in both the number of viable embryos and in plasma progesterone concentrations when compared to the treatment with Id alone. The PG mixture used in the present study did not succeed in fully reversing the Id antifertility effect.

Survival in foods of Staphylococcus aureus grown under optimal and stressed conditions and the effect of some food preservatives.

Staphylococcus aureus was grown in a rich peptone medium which became alkaline with continued incubation. Cells were grown at 37 degrees C and in the same medium containing 1 M NaCl at 46 degrees C, a temperature at which this organism can grow only when protected by NaCl. Cells of these cultures are hereafter called 37 degrees C-cells and 46 degrees C-cells, respectively. The 37 degrees C-cells harvested when the pH was 7.1 to 7.7 had decimal reduction times (D60-value) of 1.8 to 3.1 min in 50 mM pH 7.2 Tris buffer. The D60 value of 46 degrees C-cells tested in the same way, harvested from cultures at pH 6.6 to 7.6, ranged from 5.3 to a maximum of 12.8 min. In milk, green beans, peas, or beef slurry, the D60-value of 46 degrees C-cells was about four times higher than that of 37 degrees C-cells. Length of survival after freeze-drying in skim-milk powder exposed to air was longest for the cells with the highest D-value. In freeze-dried peas and media acidified with acetic and lactic acids, 46 degrees C-cells survived longer than 37 degrees C-cells. However, the sensitivity of the two kinds of cells to potassium sorbate, sodium benzoate, and sodium propionate was essentially the same, but the 46 degrees C-cells were more resistant to butylated hydroxyanisole and sodium nitrite.

Investigation of Penicillium chrysogenum Isolates for their Suitability as Starter Cultures.

One hundred twenty three isolates ofP. chrysogenum were biologically tested in brine shrimp test and screened withStaphylococcus aureus for the detection of antibacterial activity. Furthermore, they were chemically examined (thin layer chromatographic method, TLC) for the synthesis of 8 mycotoxins (citrinin, cyclopiazonic acid, mycophenolic acid, patulin, penicillic acid, PR-toxin, ochratoxin A, and roquefortine). The results indicated that 85% of the tested isolates produce roquefortine and one isolate produces cyclopiazonic acid. Considering the results of the chemical assay for mycotoxins as well as the results of the brine shrimp test and the detection of antibacterial activity, 119 (97%) of the tested isolates are not suitable to be used as starter cultures for mould-fermented meats. The extracts of only 4 isolates were subjected to further biological tests in mice and the results indicated that only one isolate was non-toxinogenic.

Fate of Mycotoxins During Processing of Foodstuffs III. Ochratoxin A During Cooking of Faba Beans ( Vicia faba ) and Polished Wheat.

The fate of ochratoxin A during cooking of faba beans and polished wheat was studied by addition of crystalline toxin before cooking in water at a level of 125 ng/g dry faba beans or raw polished wheat. Determinations were made by reversed-phase high performance liquid chromatography (HPLC) and the simple, sensitive, precise and economical method used gave a detection limit of about 0.7 ng/g. Average destruction of 16 and 20% of ochratoxin A occurred during cooking of faba beans by two methods, whereas an average of only 6% of the toxin added was destroyed after cooking of polished wheat. Thus the destruction of ochratoxin A by cooking of contaminated faba beans or polished wheat is not possible.

The effect of thyroxine on the oxygen consumption of the ocellated skink, Chalcides ocellatus (Forskal).

Acutely administered thyroxine caused significant increase in the whole body rate of oxygen consumption of C. ocellatus at temperatures between 4 and 25 degrees C. No significant increase in the oxygen consumption was observed over the voluntary body temperature range of 30-40 degrees C.

Effect of indomethacin on plasma levels of vitamin D metabolites, oestradiol and progesterone in rabbits during early pregnancy.

1. Inhibition of prostaglandin (PG) synthesis by indomethacin (Id) during early pregnancy in rabbits apparently disrupts the process of sex steroid production by the ovaries. 2. The role of PGs as mediators in steroidogenesis was tested by investigating the effect of Id alone or in combination with progesterone, with oestradiol and progesterone, or with a mixture of PGs, on plasma levels of 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) in rabbits at an early stage of pregnancy. 3. Id alone significantly reduced plasma levels of both 25(OH) D and 1,25(OH)2D. Treatment with Id in combination with either oestradiol and progesterone, or with a mixture of PGs, resulted in the restoration of plasma levels of both vitamin D metabolites as well as the restoration of plasma levels of progesterone, to their control values.

Fate of Mycotoxins During Processing of Foodstuffs I-Aflatoxin B1 During Making of Egyptian Bread.

Fate of aflatoxin B1 during making of Egyptian bread from whole wheat flour spiked with aflatoxin Bl (0.1 µg/g) was investigated. Determinations were made by reversed-phase high pressure liquid chromatography (HPLC) after formation of aflatoxin B2a with trifluoroacetic acid. An average of 19% of the toxin added was destroyed after preparation of fermented dough, whereas subsequent baking (350°C, 2 min) reduced the amount of toxin by an additional 36% to give a total average destruction of 55%. Thus risks remain in preparing Egyptian bread from aflatoxin-contaminated wheat flour.

Effect of indomethacin on egg transport and pregnancy in the rabbit.

Treatment of rabbits with indomethacin (10 mg/kg/day) 48 hr before mating, and with 20 mg/kg at 12 hr followed by 8 mg/kg at 48, 72 or 96 hr after mating did not affect the rate of egg transport through the oviduct. Indomethacin treatment at the time of implantation interfered with pregnancy and caused degeneration and resorption of embryos. These results suggest that inhibition of prostaglandin synthesis does not directly affect egg transport, but that prostaglandin appears to be required for the retention of implanted embryos.

Occurrence of Vibrio parahaemolyticus in selected marine invertebrates, sediment, and seawater around Alexandria, Egypt.

Samples of seawater, sediment, and the following invertebrates were collected from the Mediterranean Sea in the neighborhood of Alexandria, Egypt: sea urchins (Echinus spp.), clams (Tapes spp.), and wedge shells (Donax trunculus). A total of 165 samples were collected from November 1979 to July 1980. Average counts (per 100 mL or 100 g) of Vibrio parahaemolyticus content were as follows: seawater, 36; sea urchins, 349; sediment, 436; wedge shells, 534; clams, 1872. Samples collected in the summer months contained higher levels of V. parahaemolyticus than winter samples.

Adaptational changes in Staphylococcus aureus MF31 grown above its maximum temperature when protected by NaCl: physiological studies.

Staphylococcus aureus MF31 can grow at 46 degrees C, 2 degrees C above its normal maximum temperature of growth if 1 M NaCl is added to the medium. In the present work we show that monosodium glutamate, proline, threonine, aspartic acid, and betaine (in order of decreasing effectiveness) also enabled cells to grow at 46 degrees C. Cells grown at 46 degrees C in he presence of salt (protected or P cells) accumulated glutamate more rapidly than cells grown at 37 degrees C without salt (normal or N cells) and contained an increased amino acid pool. The principal constituents of this pool were dicarboxylic amino acids and proline. Turbidimetric evidence suggests that NaCl caused plasmolysis in S. aureus. The P cells, although grown in 1 M NaCl, had about the same Cl- and K+ content as the N cells grown without added NaCl. P cells had increased heat resistance but high concentrations of CaCl2 in the heating menstruum reduced their D55 value from a maximum of 214 min to less than 30 s. We suggest that growth at 46 degrees C in 1 M NaCl can be explained, in part at least, by the increased amino acid pool internal to the cell and the external osmotic support given by Cl- anions excluded by the cell.