IN VITRO STUDY OF CONCENTRATION-EFFECT AND TIME-COURSE PATTERN OF WHITE ALUM ON ESCHERICHIA COLI O157:H7 GROWTH.

BACKGROUND: Nowadays, the demand for antibacterial fabrics has increased. White alum is used for oral aphthous ulcers treatment in traditional medicine of Sistan city, Sistan and Baluchistan Province, Iran, and also as a flocculent for water purification. This study is aimed to evaluate the effect of concentration and time on antibacterial activity of white alum on Escherichia coli O157:H7. MATERIALS AND METHODS: 0.25, 0.5, 1 and 2% concentrations of white alum were added to 108 CFU of Escherichia coli O157:H7. Optical Density was recorded for 4 hours. Data obtained were analyzed using Repeated Measure and One-way ANOVA by SPSS. RESULTS: Results revealed the effectiveness of white alum in the growth of the tested bacterium. The white alum was found to be potent against Escherichia coli O157:H7 at a concentration above 1% (p<0.05). Also, its effect is dose and time dependent, as well as other disinfectants. CONCLUSION: A wide variety of natural products has been under scrutiny for their clinical potential, both in terms of prevention and treatment. Strong antibacterial activity of white alum compared with control was shown against tested bacterium. In conclusion, white alum can be used as an inhibitor of bacterial growth, especially for Escherichia coli O157:H7.

Determination of yield stability in advanced potato cultivars as affected by water deficit and potassium humate in Ardabil region, Iran.

This experiment was done on the three potato cultivars [Agria (susceptible), Satina (semi-tolerant) and Ceaser (tolerant to water deficit)] and three irrigation treatments (after 30 mm evaporation from basin class A, after 60 mm evaporation + spraying by Potassium Humate, and after 60 mm evaporation from basin class A) for two locations in 2007. Experimental design was Split Plot with three replications. Potassium Humate spraying (250 mL ha(-1)) were done in three stages of emergence, before tuberization and during tuberization period. Combined analysis of variance showed that there were significant differences between locations, cultivars, irrigation treatments and location x cultivars interaction as effect on tuber yield. Comparison of means for irrigation treatments showed that spraying by Potassium Humate in stress condition induced increasing of tuber yield. Spraying by Potassium Humate in water deficit condition increased tuber yield up to 11.01 ton ha(-1). Ceaser had the highest tuber yield. It had higher tolerance to water deficit as well. Ceaser had a high potential in control and severe stress. Decrease in yield of Ceaser after 60 mm evaporation + spraying by Potassium Humate and after 60 mm evaporation from basin class A, relative to control (after 30 mm evaporation from basin class A) was 1.03 and 13.08 ton ha(-1) but for Satina was 7.83 and 16.61 ton ha(-1), respectively. Satina had the lowest Environmental Variance, Environmental Variance Coefficient, Finlay and Wilkinson's and Eberhart and Russell's model and was the most stable cultivar. Lin and Binns parameter showed that Ceaser and Satina were the most stable cultivars. Results of GMP, STI and MSTI were very considerable and Ceaser and Satina had a high yield in water stress and control conditions.

Shortening transplantation periods of potato plantlets by use of potassium humate and kadostim and their effects on mini-tuber production.

Plantlets produced from meristem culture of six advanced cultivars (Agria, Advanced clone 397007-9, Marfona, Sante, Satina and Ceaser) propagated by single node cuttings arranged in a RCBD base factorial design with ten replications. Factor A was plantlets produced from meristem culture of advanced cultivars and factor B was seven treatments (four concentrations of potassium humate as 0.5, 1, 1.5 and 2 mL, one concentrations of kadostim as 1 mL, compound concentration of potassium humate and kadostim as 1 ml L(-1) MS media culture and without them as control). Produced plantlets transplanted into the planting beds of Pitmass (Biolan) with punce (1:1 v/v) in the greenhouse. Some of traits measured such as average weight and number of mini-tuber per plant after harvesting. Results of analysis of variances showed the significant differences between effects of kadostim and potassium humate on advanced cultivars, for transplantation into the greenhouse, stem solidity and rhizo-genesis characters. So transplantation days decreased from 30 to 13 days in MS media culture with compound of potassium humate + kadostim by concentration of 1 ml L(-1) MS media culture, also decreased to 15 days in MS media culture with kadostim by concentration of 1 ml L(-1) MS media culture and also decreased to 22 days in MS culture with potassium humate by concentration of 1 and 1.5 ml L(-1) MS media culture and plantlets had the highest stem solidity and better rhizo-genesis in all of treatments. Agria, Sante and Marfona transplanted earlier and Ceaser transplanted later than others to the greenhouse. Compound concentration of potassium humate and kadostim 1 ml L(-1) MS media culture had the highest number of mini-tubers per plant and potassium humate 0.5 ml L(-1) MS and Kadostim 1 ml L(-1) MS had the highest mini-tuber weight per plant and average of mini-tuber weight per plant. Agria had the highest number and average of weight of mini-tubers per plant. Potassium humate 0.5 ml L(-1) MS in satina, kadostim 1 ml L(-1) MS in marfona and potassium humate + kadostim 1 ml L(-1) MS in Agria had the highest number of mini-tubers per plant. Increasing rate of weight and number of mini-tubers per plant with potassium humate and kadostim in all of advanced cultivars were more than control.