Abstract: Dunaliella salina has great potential as a system for generating commercially valuable products, including beta-carotene, pharmaceuticals, and biofuels. Our goal is to improve this potential by enhancing growth rate and other properties of D. salina under optimal growth conditions. We used ethyl methane sulfonate (EMS) to generate random mutants in D. salina KU11, a strain classified in Thailand. In a preliminary experiment, we first treated D. salina cells with 0%, 0.8%, 1.0%, 1.2%, 1.44% and 1.66% EMS to generate a killing curve. After that, we randomly picked 30 candidates from approximately 300 isolated survivor colonies from the 1.44% EMS treatment (which permitted 30% survival) as an initial test of the mutant screen. Among the 30 survivor lines, we found that 2 strains (mutant #17 and #24) had significantly improved growth rates and cell number accumulation at stationary phase approximately up to 1.8 and 1.45 fold, respectively, 2 strains (mutant #6 and #23) had significantly decreased growth rates and cell number accumulation at stationary phase approximately down to 1.4 and 1.35 fold, respectively, while 26 of 30 lines had similar growth rates compared with the wild type control. We also analyzed cell size for each strain and found there was no significant difference comparing all mutants with the wild type. In addition, mutant #24 had shown an increase of biomass accumulation approximately 1.65 fold compared with the wild type strain on day 5 that was entering early stationary phase. From these preliminary results, it could be feasible to identify D. salina mutants with significant improved growth rate, cell accumulation and biomass production compared to the wild type for the further study; this makes it possible to improve this microorganism as a platform for biotechnology application.
Abstract: To evaluate the effect of intramuscular administration
of vitamin A in pregnant dairy cows during late stages of pregnancy,
on vitamin A status of neonatal calves, a total of 30 cows were
randomly selected and divided into three groups; two treatment
groups and one control group. Single intramuscular injection of
2000000 IU vitamin A; was carried in 10 dairy cows at 7 months of
pregnancy (group 1). In second group of treated animals (10 cows)
the injection was performed in 8 months of pregnancy (group 2). Ten
pregnant dairy cows were received saline injection as placebo and
selected as control group. Blood samples were collected from
experimental dairy cows at 7 and 8 months of pregnancy as well as
their newborn calves’ pre and after colostrum intake. There was no
significant difference between vitamin A and β-carotene
concentration of dairy cows of three groups in two last months of
pregnancy (P> 0.05). Vitamin A concentration of calves of two
treatment groups before and after receiving of colostrum were
significantly higher than that in control group (P< 0.05). There was
no significant difference between serum concentrations of vitamin A
in calves of two treated groups (P> 0.05). β-Carotene concentration
of serum samples of dairy cows and neonatal calves of three groups
were not significantly different as compared with together. From
results of the present study it can be concluded that single injection of
vitamin A during at 7 or 8 month of pregnancy can significantly
increase level of vitamin A in their colostrum and neonatal calves.
Abstract: Raman spectroscopy is currently a part of the instrumentation suite of the ESA ExoMars mission for the remote detection of life signatures in the Martian surface and subsurface. Terrestrial analogues of Martian sites have been identified and the biogeological modifications incurred as a result of extremophilic activity have been studied. Analytical instrumentation protocols for the unequivocal detection of biomarkers in suitable geological matrices are critical for future unmanned explorations, including the forthcoming ESA ExoMars mission to search for life on Mars scheduled for 2018 and Raman spectroscopy is currently a part of the Pasteur instrumentation suite of this mission. Here, Raman spectroscopy using 785nm excitation was evaluated for determining various concentrations of beta-carotene in admixture with polyaromatic hydrocarbons and usnic acid have been investigated by Raman microspectrometry to determine the lowest levels detectable in simulation of their potential identification remotely in geobiological conditions in Martian scenarios. Information from this study will be important for the development of a miniaturized Raman instrument for targetting Martian sites where the biosignatures of relict or extant life could remain in the geological record.