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Introduction Mitogenetic effect in Yeast cell Supe from Soya seeds: Spectral distribution and  temperature dependence Conclusions References

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The effect of self irradiation on yeast cell has been investigated in collaboration with M. Yanbastiev (Bulgaria) [1], following the same experimental protocol used by Gurwitsch.

Circular samples of 15 mm diameter taken from the solid culture were used for self irradiation experiments and for control. The samples to be self irradiated were put one in front of the other at 6 mm of distance for 30 seconds in air, while the control cells were maintained far one from each other. Samples and controls were then maintained for 8 min in the 26 °C thermostat, thereafter biological processes were stopped by adding a formaldehyde solution.

Irradiated samples and controls were treated thereafter by the double hidden procedure. On each sample 1000 cells have been observed; the measurement consisted in counting the number of cells which exhibited a young gemma, i.e. a gemma having size smaller than 1/10 of the mother cell.

The above described procedure has been performed on a total of 104 sample-control couples in the four experiments.

The numbers of young gemmae on 1000 cells have given the basis for the statistical treatment of the results; as index of the effect it has been chosen

Pi = 100 x (Ni - N0i) / N0i

where Ni is the number of gemmae/1000 cells in irradiated samples, and N0i is the corresponding number in the control sample. In tab I is reported the statistical elaboration of the results for the four experiments.
 

Table I - Mitogenetic effect index and statistical parameters for the yeast solid culture
 

Experiment	Average value P	Average st. deviation	Gaussian %
I	5	6.1	32
II	25.5	8.8	30
III	4.6	7.5	13
IV	8	6.2	39

The results of all the performed experiments, within their statistical reliability, give a uniform evidence of the larger rate of gemmation of self irradiated cell in comparison with controls.

Experiments from other researchers on mitogenetic effect have obtained negative results [2]. The main cause to these different results can be due to the different experimental conditions of the experiments, as for instance, the measured parameter, the modality of self irradiation, the type of culture,....

In order to investigate the influences of the above differences, it has been repeated the above experiment under different experimental conditions. The experiment was performed with the collaboration of Z. Rajfur and D. Sitko (Poland).

As first it was changed the culture medium that was liquid, instead of a solid one. The measured parameter (yeast cell count) and the condition of self irradiation remained similar as in the previous experiment. Moreover the cell growth and the SUPE from yeast has been measured and reported in fig. 1, where it is shown that the maximum in emission is correlated with the maximum in the growth rate; the maximum took place at about the times in which the experiment of self irradiation is performed.
 

Fig. 1 - Ultraweak photon emission from three yeast liquid cultures (dashed and solid lines); the squares refer to the cell growth curve. In the X-axis the elapsed time from the inoculum is reported

For each series of experiments (14 has been made), four cuvettes were prepared: two of 0.5 ml (1 mm depth and called A1 and A2) and two of 5 ml (10 mm depth and called B1 and B2):

A1 was used as receiver and B1 as sender, A2 and B2 were used as control. They were irradiated for 30" at ambient temperature and then left for 10' at 28 °C; afterwards the biological process were stopped by formaldehyde. The young gemmae were then counted as in the previous experiment.

As receiver, it has been used a 1 mm depth cuvette, different from the sender, in order to reduce the eventual contribution of irradiation from the surrounding yeasts of the same cuvette (decay distance of UV radiation in the used culture medium was about 2 mm), while as sender it was used a 10 mm cuvette in order to have more quantity of emitted radiation.

The parameter P, as defined before, was calculated for the following three combination of cuvettes:

1) P1= (A1 - A2) / A2 x 100 (1 mm cuvettes)

2) P2= (B1 - B2) / B2 x 100 (10 mm cuvettes)

3) P3= (B2 - A2) / A2 x 100 (10 mm vs 1mm cuvettes)

The parameters so calculated are reported in fig. 1 and the average values with the corresponding standard deviation and reliability are reported in tab II.
 

Table II - Mitogenetic effect index and statistical parameters for different irradiation conditions in the yeast liquid culture
 

Experiment	Average value P	Average st. deviation	Reliability %
P1	15	5	99.8
P2	3	3	71.3
P3	7	4	95.4

It is evident that the first combination is the most suitable one for the mitogenetic effect. P1 refers in fact to the comparison between two "thin" cuvettes, the control A2 and the irradiated sample A1, and the influence of the "internal" radiation should be very low; here, as we expected, the effect is very enhanced. The second parameter P2 gives a very poor effect in B1 as compared with the control B2, according the hypothesis that the internal radiation in "bulk" samples masks the effect of the "external" radiation. The third parameter P3 gives indication of some effect also between two samples not self irradiated; this should be the effect of the "internal" radiation in the "bulk" sample B2 as compared with a "thin" sample, where the "internal" radiation is ineffective.

Apart the P1 parameter that seems to have a good reliability, the above results, before to become consolidate, should be improved by repeating the experiments in order to have better measurement conditions. However they confirm the existence of the mitogenetic effect also for liquid culture.

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