Fermentation Performance of A Bakery Yeast Strain in Normal and Very High Gravity Media With Different Nitrogen Content

Sadiah Djajasoepena, Sista S. Yuliana, Saadah D. Rachman, Safri Ishmayana

ABSTRACT
Fermentation performance of the yeast Saccharomyces cerevisiae is influenced, among others, by growth media composition. Media with complex nitrogen source tend to give better fermentation performance. In the present study, we investigate fermentation performance of a bakery yeast strain in normal (20% w/v glucose) and very high (40% w/v glucose) gravity media with different nitrogen content. We used yeast extract – peptone (YEP) media with varying concentration of yeast extract, bacteriological peptone, ammonium sulphate, and potassium hydrogen phosphate in the media. For comparison, yeast nitrogen base (YNB) media was used. We found that increasing YEP media component in the media lead to better cell growth, cell health and fermentation performance. The cell appeared to overcome hyperosmotic stress due to high glucose concentration when higher content of YEP used in the media, as indicated by better cell viability. Surprisingly, cell grown in YNB media was observed has the highest viability throughout the fermentation, even though the fermentation performance was poorer. The best fermentation was observed when media with the highest YEP composition was applied. In this media, when normal and very high gravity media were used, ~97 and ~75% of the sugar were consumed, respectively. It was also found that ethanol yield was 0.327 and 0.277 g.g-1 for normal and very high gravity media, respectively. The result of the present study showed that nitrogen content present in the media is really important for yeast growth and fermentation performance.

Key words: Very high gravity media, ethanol fermentation, bakery yeast, nitrogen content

Epigenetic Analysis of OCT4 Gene in Blood Cells of Normal and Leukemic Patients

Touseef Rehan, Riffat Tahira, Tabassum Rehan, Ayesha Bibi, Amir Ali Khan

ABSTRACT
Epigenetic changes are one of the many causes of cancer. Our research interest lie in the alteration of methylation in the CG in the promotor of OCT4 in the DNA of ALL(acute lyphoblastic Leukaemia). We examined the alteration of methylation of CG at three CCGG loci in the promotor of Oct4 by restriction digestion of CCGG using MSPI and HPaII followed by PCR to amplify the region flanking the CCGG. This simple yet effective methology was used to assess the alteration of methylation in the CG of specific CCGG in the 60 control and 50 ALL patients. CCGG sequence at 2 loci was selected in the 2.7 Kb upstream regulatory region of Oct4 gene. The DNA from the ALL patients were digested with MSPI and HpaII followed by PCR using the primers that flank the CCGG. The PCR bands were observed in the control while they were absent in the DNA of ALL patients indicating the alteration of methylation at these CGs. Our results demonstrate that the specific CG in the CCGG inside the promoter of OCT4 undergoes demthylation in the ALL patients compared to normal. However, research is needed to confirm our preliminary findings.

Key words: Alteration of methylation, Leukaemia, digestion of CCGG, PCR

Impact of Exogenously Applied Ascorbic Acid on Growth, Some Biochemical Constituents and Ionic Composition of Guar (Cymopsis Tetragonoloba) Subjected to Salinity Stress

Humaira Gul, Rafiq Ahmad and Muhammad Hamayun

ABSTRACT
The present study was undertaken to examine the effects of exogenous application of 0.5mMascorbic acid (AA) on growth, associated biochemical parameters and ionic composition in (Cymopsis tetragonoloba) grown under different doses of seasalt irrigation. In a pot experiment, AA was applied through foliar-spray at the concentrations of 0 and 0.5mM with or without 0, 2.5 dS/m-1 and 5 dS/m-1 seasalt concentration. Vegetative and reproductive growth measurements (plant height, root length, number of leaves, leaf area, fresh and dry biomass, number of pods per plant, pod weight per plant, seed number per plant and seed weight per plant), chlorophyll a, b, total chlorophyll, protein, carbohydrates, sodium and potassium ions indifferent plant parts were recorded to study the effects of these treatments. Thepresence of salt reduced the vegetative and reproductive growth parameters, chlorophyll a, b, total chlorophyll, proteins and potassium ions concentration in different parts of Cymopsis tetragonoloba plants. Total carbohydrates and sodium ion concentration in different plant parts showed increase while increasing in sea salt concentration in irrigation water. The AA application not only mitigated the inhibitory effects of salt stress but also induced a stimulatory effect on all the studied growth parameters.

Key words: Salinity, Ascorbic acid, yield, chlorophyll, protein, carbohydrates, sodium, potassium.

Construction and Application of Electrolytic Cell for Iodine Determination

Nasrullah Shah, Muhammad Bilal Arian, Wajid Ali Khan

ABSTRACT
Iodine is very important element and has a key role in different fields of life so its analysis is of great significance. For the determination of iodine usually iodometric methods are used, but the range of this method is up to molar level. In the present work a simple, easy and economically feasible method is electroanalytical method is developed. An electrolytic cell for the determination of iodine was constructed which was based on redox reaction. The determination of iodine was done by using KI electrolysis mechanism. NaCl (10 ppm) was taken as a standard and solutions of different iodine concentration were added at each time and current (µA) were recorded, with the help of which standard curve was prepared. It was applied to various unknown standard samples and appropriate results were obtained. Similarly to check the practical applicability of the method it was successfully applied to different table salts (Swaad and Raaz). The range of this method is up to micro level (upto 10 ppm) and also had a considerable error rang but that will be overcome by further modification of this method.

Key words: Iodine, determination, electrolytic cell