Background: Cell growth underlies many key cellular and developmental processes, yet a limited number of studies have been carried out on cell-growth regulation. Comprehensive studies at the transcriptional, proteomic and metabolic levels under defined controlled conditions are currently lacking.

No abstract

This pa~r was selected for presentabcm by an SPE Prcgram Committee following rev!aw of Imformat!on W"tai"ed M a" abstract $&mifted by tha authm(s) Co"te"ts of the pap,gr, aa presentad, have not baen reviewed by the Swety of Patroleum Engmaers and ara subject to mrrecbon by the author(s) The material, as presented, does not necessarily reflect any poslbon of the Society of Petroleum Engineers, Its offIcars, or membrs Papers presented at SPE meetmgs are sublect to publl=bon rev!aw by Edltorlal Committees of the Smtety of Petroleum Engineers Electromc reproduction, d!stribubon, or storage of any part of this papar for wmmem!al pu~ses w!thl the wrttten wnsant of the Society of Petrolaum Engineers IS prohrbltad Perm!sslon to raprcdum Im print is rastrlcled to an abstract of not more than 300 words. !llustrabons may not be cop!ed The abstract must contain Wnsplcuous nowledgment of where and by whom the pa~r was presented Wr!te L!brarlan, SPE, P O Box 8338w, Rtiardson.~75083-38%, U. S A, fax 01-972.952-9435Abstract This paper presents new production decline curves for analyzing well production data from radial and vertically fractured oil and gas wells, These curves have been developed by combining Decline curve and Type curve analysis concepts to result in a practical tool which we feel can more easily estimate the gas (or oil ) in place as well as to estimate reservoir permeability, skin effect, fracture length and conductivity, etc. Accuracy of this new method has been verified with numerical simulations and the methods have been used to perform analyses using production data from several different kinds of gas wells. Field and simulated examples are included to demonstrate the applicability and versatility of this technology.Decline curve analysis methods, in a variety of forms, have been used in the petroleum industry for more than fifiy years to analyze production data and forecast reserves. Type curve analysis methods have become popular, during the last thirty years, to analyze pressure transient test (e.g. buildup, draw-down) data.result is the development of these new production decline type curves.These new production decline type curves represent an advancement over previous work because a clearer distinction can be made between transient and boundary dominated flow periods.The new curves also contain derivative finctions, similar to those used in the pressure transient literature to aid in the matching process. These production decline curves are, to our knowledge, the first to be published in this format specifically for hydraulically fractured wells of both infinite and finite conductivity. Finally, these new curves have been extended to utilize cumulative production data in addition to commonly used rate decline data.

The designation of the yeast 2 mu circle as a "selfish" DNA molecule has been confirmed by demonstrating that the plasmid is lost with exponential kinetics from haploid yeast populations grown in continuous culture. We show that plasmid-free yeast cells have a growth rate advantage of some 1.5%-3% over their plasmid-containing counterparts. This finding makes the ubiquity of this selfish DNA in yeast strains puzzling. Two other factors probably account for its survival. First, the rate of plasmid loss was reduced by allowing haploid populations to enter stationary phase periodically. Second, it was not possible to isolate a plasmid-free segregant from a diploid yeast strain. Competition experiments demonstrated that stability in a diploid is conferred at the level of segregation and that plasmid-free diploid cells are at a selective advantage compared with their plasmid-containing counterparts. Yeast cells in nature are usually homothallic and must frequently pass through both diploid and stationary phases. The 2 mu plasmid appears to have evolved a survival strategy which exploits these two features of its host's life cycle.

~_ _ _ _ _ _~ _ _ _ _ _ _ _~The production of the pigments actinorhodin and undecylprodigiosin by Stveptomyces coelicolor A3(2) was examined in a chemically defined medium which permits dispersed growth of the organism. The physiological controls on the production of the two pigments were markedly disparate. Actinorhodin production occurred mainly in the stationary phase of batch cultures grown with glucose and sodium nitrate as the principal carbon and nitrogen sources. In the same batch cultures, undecylprodigiosin accumulated during the exponential growth phase. The production of both pigments was sensitive to the levels of ammonium and phosphate in the medium. Actinorhodin production was exquisitely sensitive to ammonium concentration, and was completely inhibited by as little as 1 mM-ammonium chloride, whereas more than 50 mhl-amnonium chloride was required to prevent undecylprodigiosin production. A similar, but less extreme effect was seen with phosphate: actinorhodin production was completely inhibited by 24 mM-phosphate, whereas undecylprodigiosin was still formed at this high phosphate concentration. The effects of ammonium inhibition of pigmented antibiotic production were relieved by reducing the concentration of phosphate in the medium, but changing the ammonium concentration had no effect on phosphate inhibition. Thus the regulation of pigment production by these two nutrients is interrelated, with phosphate control being epistatic to that of ammonium. The results implicate a phosphorylated intermediate as a major regulator of secondary metabolite synthesis by S. coelicolor.