Induction and Analysis of Synchronous Meiotic Yeast Cultures.

Meiosis in Saccharomyces cerevisiae can be induced by deprivation of nutrients. Here, we present a protocol for inducing synchronous meiosis in SK1, the most efficient and synchronous yeast strain for meiosis, by exposing SK1 cells to liquid medium that contains potassium acetate as a nonfermentable carbon source and lacks nitrogen. These synchronous meiotic yeast cultures can be subjected to a range of molecular and cytological analyses, making them useful for investigating the genetic and molecular determinants of meiosis.

Structural correlates of cytoplasmic and chloroplast lipid body synthesis in Chlamydomonas reinhardtii and stimulation of lipid body production with acetate boost.

Light microscopy and deep-etch electron microscopy were used to visualize triacylglyceride (TAG)-filled lipid bodies (LBs) of the green eukaryotic soil alga Chlamydomonas reinhardtii, a model organism for biodiesel production. Cells growing in nitrogen-replete media contain small cytoplasmic lipid bodies (α-cyto-LBs) and small chloroplast plastoglobules. When starved for N, ß-cyto-LB formation is massively stimulated. ß-Cyto-LBs are intimately associated with both the endoplasmic reticulum membrane and the outer membrane of the chloroplast envelope, suggesting a model for the active participation of both organelles in ß-cyto-LB biosynthesis and packaging. When sta6 mutant cells, blocked in starch biosynthesis, are N starved, they produce ß-cyto-LBs and also chloroplast LBs (cpst-LBs) that are at least 10 times larger than plastoglobules and eventually engorge the chloroplast stroma. Production of ß-cyto-LBs and cpst-LBs under the conditions we used is dependent on exogenous 20 mM acetate. We propose that the greater TAG yields reported for N-starved sta6 cells can be attributed to the strain's ability to produce cpst-LBs, a capacity that is lost when the mutant is complemented by a STA6 transgene. Provision of a 20 mM acetate "boost" during N starvation generates sta6 cells that become so engorged with LBs-at the expense of cytoplasm and most organelles-that they float on water even when centrifuged. This property could be a desirable feature for algal harvesting during biodiesel production.

Bioaugmentation to degrade the organic de-icers acetate and monopropylene glycol at low temperatures.

Two de-icers, potassium acetate and monopropylene glycol (MPG), used widespread as a runway and wing de-icer respectively, can exert high BOD in the surrounding waters. A bioaugmentation approach to degrade these de-icer compounds in the drainage water prior to discharge has been tested. A microbial consortium originating from soil was enriched at low temperatures (4 degrees C) in order to adapt to wintertime conditions. With 0.05 g CDW/L of biocatalyst, maximum specific removal rates up to 1.46 and 3.33 g acetate/g CDW d at 4 degrees C were achieved with and without biostimulation respectively. An acetate:MPG mixture of 1:3 at a total COD concentration of 0.80 and 1.20 g/L was degraded in 12 days by 83 and 70% respectively. Bioaugmentation in the field over a period of 25 days showed a removal of 88% MPG compared to 46% in the control. These results demonstrate that bioaugmentation of airport runoff water can be successfully applied to prevent organic de-icer compounds from entering the receiving surface waters.

Sodium acetate enhances hydrogen peroxide production in Weissella cibaria.

AIMS: To investigate hydrogen peroxide production by lactic acid bacteria (LAB) and to determine the key factors involved. METHODS AND RESULTS: Six strains of Weissella cibaria produced large amounts (2.2-3.2 mmol l(-1)) of hydrogen peroxide in GYP broth supplemented with sodium acetate, but very low accumulations in glucose yeast peptone broth without sodium acetate. Increased production of hydrogen peroxide was also recorded when strains of W. cibaria were cultured in the presence of potassium acetate, sodium isocitrate and sodium citrate. Oxidases and peroxidases were not detected, or were present at low levels in W. cibaria. However, strong nicotinamide adenine dinucleotide (NADH) oxidase activity was recorded, suggesting that the enzyme plays a key role in production of hydrogen peroxide by W. cibaria. CONCLUSIONS: Weissella cibaria produces large quantities of hydrogen peroxide in aerated cultures, in a process that is dependent on the presence of acetate in the culture medium. NADH oxidase is likely the key enzyme in this process. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study showing that sodium acetate, normally present in culture media of LAB, is a key factor for hydrogen peroxide production by W. cibaria. The exact mechanisms involved are not known.

[Effect of acetate on synthesis of exopolysaccharide ethapolan during Acinetobacter sp. B-7005 cultivation on the medium with ethanol].

A possibility of removal of C2-metabolism limiting and increasing of activity of acetyl-CoA-synthesis in Acinetobacter sp. B-7005--producer of exopolysaccharide (EPS) ethapolan with acetate introduction in the medium with ethanol. When adding potassium acetate 0.1% of into the medium without sodium cations containing 1% ethanol and 0.0009% calcium pantotenate at the stage of obtaining inoculate and at EPS biosynthesis, it is possible to realize the process of ethapolan production on nonbuffered medium in which total content of salts is reduced 4 times without decreasing the synthesis indices and rheological properties.

[Establishment of high-yield suspension cell line of Curcuma zedoaria (Berg.) Rosc and study on the volatile oil synthesis-controlling with precursors].

The condition for high-yield suspension cell line and the precursors of volatile oil synthesis of Curcuma zedoaria (Berg.) Rosc were studied. The results showed that the light yellow particle callus was suitable for establishment of the high-yield suspension cell line. The optimum conditions for cell growth were MS medium added 15-30 g/L glucose and 15-30 g/L sucrose (1:1) as carbon source, the total concentration of 80 mmol/L nitrogen source combined NH4+ with NO3- (1:3), hormones of 3.0-5.0 mg/L 6-BA, 1.0 mg/L 2,4-D and dark culture after 10-15 days light culture. The 229 g/L cell (FW) and 2.11% content of volatile oil were obtained in vitro. The addition of precursors of calcium pantothenate, ammonium acetate and potassium acetate during the middle period of the cell suspension culture enhanced the volatile oil content respectively, and ammonium acetate was most effective among them. The highest yield of volatile oil obtained was 3.11% and 8.27 g/L respectively , which was 1.25 and 1.2 times of the control group.

Low temperature biodegradation of airport de-icing fluids.

The biodegradabilities of glycol- and acetate-based aircraft de-icing fluids on airport surfaces have been investigated at three temperatures between 0 degrees C and 10 degrees C. The aqueous solubilities of these substances can result in high BOD loadings in runoff and pose serious toxicity problems in receiving waters. The measured surface biodegradation rates for de-icing products based on ethylene/diethylene glycol (Konsin), propylene glycol (Kilfrost) and potassium acetate (Clearway) at 4 degrees C were 0.082, 0.073 and 0.033 day(-1). The resulting reductions in the potential BOD loadings, of a single application of a typical mixture of these products, over a 5 day biodegradation period are predicted to be 32.9%, 30.2% and 21.4%, respectively at 8 degrees C, 4 degrees C and 1 degrees C. For consecutive daily applications, the comparable cumulative reductions over 5 days are 20.8%, 18.9% and 13.3%. The subsequent savings in the amount of treatment required for airport runoff prior to safe discharge to receiving waters are discussed and hence the relevance of surface biodegradation processes to the design of stormwater treatment systems involving the wash-off of biodegradable pollutants following retention on urban surfaces.

[Genetic control of growth and development of yeast Saccharomyces cerevisiae cells. Phenotypic selection of mutants among strains of the Peterhof genetic collection]. / Geneticheskii kontrol' rosta i razvitiia kletok drozhzhei Saccharomyces cerevisiae. Fenotipicheskii otbor mutantov sredi shtammov Petergofskoi geneticheskoi kollektsii.

Results of identifying phenotypes intrinsic to mutations of genes that regulate the activity of the signal transduction pathway of RAS-cyclic adenosinemonophosphate in six strains belonging to the Peterhof genetic collection of the yeast Saccharomyces cerevisiae are presented: an increase or decrease in the amount of the accumulated glycogen, resistance or sensitivity to heat shock and nitrogen starvation, and the growth and viability in media containing unfermentable carbon sources (potassium acetate, ethanol, and glycerol) at temperatures 30 and 70 degrees C. Collectively these phenotypic characteristics in five examined yeast strains can be interpreted as indicating disturbances in the activity of the RAS/cAMP pathway. However, the discrepancies revealed between cellular phenotypes in these strains and in the strains with a decreased or increased activity of the RAS/cAMP pathway did not allow them to be assigned to a particular functional activity group. The inconsistencies between phenotypes detected in this study may be prerequisites for the identification of new genes responsible for this signal transduction pathway or new mutations in the known genes that determine other phenotypic combinations.

Better conditions for mammalian in vitro splicing provided by acetate and glutamate as potassium counterions.

We demonstrate here that replacing potassium chloride (KCl) with potassium acetate (KAc) or potassium glutamate (KGlu) routinely enhances the yield of RNA intermediates and products obtained from in vitro splicing reactions performed in HeLa cell nuclear extract. This effect was reproducibly observed with multiple splicing substrates. The enhanced yields are at least partially due to stabilization of splicing precursors and products in the KAc and KGlu reactions. This stabilization relative to KCl reactions was greatest with KGlu and was observed over an extended potassium concentration range. The RNA stability differences could not be attributed to heavy metal contamination of the KCl, since ultrapure preparations of this salt yielded similar results. After testing various methods for altering the salts, we found that substitution of KAc or KGlu for KCl and MgAc(2)for MgCl(2)in splicing reactions is the simplest and most effective. Since the conditions defined here more closely mimic in vivo ionic concentrations, they may permit the study of more weakly spliced substrates, as well as facilitate more detailed analyses of spliceosome structure and function.