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Effects of Turbidity on Gilling Rates and Oxygen Consumption on Green Sunfish, Lepomis cyanellus

Description: Laboratory studies conducted at 5, 15, 25, and 35 C measured changes in gilling rates and oxygen consumption of green sunfish in response to exposure to bentonite clay suspensions. The tests indicate that gilling rates are not affected by bentonite clay suspensions below 2125 FTU at 5 C, 1012 FTU at 15 C, and 898 FTU at 25 C. At turbidity levels exceeding 1012 FTU at 15 C and 898 at 25 C, gilling rates increased 50-70%. Tests were inconclusive at 35 C. Oxygen consumption rates were found to be unaffected by turbid suspensions below 3500 FTU at all four temperatures. Evidence suggests that increased gilling rates under highly turbid conditions are a means of compensating for reduced respiratory efficiency and a strategy for maintaining a constant oxygen uptake. Evidence indicates that the cost of increased gilling rates is probably met by a reduction in activity.
Date: May 1974
Creator: Horkel, John Duane
Partner: UNT Libraries

Final Report for Grant DE-FG02-90ER61072

Description: This is the final report for the work done by our research group at the Atmospheric Sciences Research Center for the US DOE Atmopheric Radiation Measurement (ARM) Program. We were involved from the beginning of the ARM effort; we designed the Multi-filter Rotating Shadowband Spectroradiometer (MFRSR) which was widely deployed (and still operational in ARM) and through the years did a wide variety of data analysis on the returned data from these instruments. We also developed the Rotating Shadowband Spectroradiometer, which ARM deployed and also still deploys. Many scientific papers have been written using the data from these instruments, and the ongoing data streams remain part of the current ARM effort. Earlier reports contain our progress from previous grant periods, this report covers the last period and provides references to published work.
Date: February 20, 2006
Creator: Harrison, Lee
Partner: UNT Libraries Government Documents Department

Asotin Creek ISCO Water Sample Data Summary: Water Year 2002, Annual Report 2001-2002.

Description: The Pomeroy Ranger District operates 3 automated water samplers (ISCOs) in the Asotin Creek drainage in cooperation with the Asotin Model Watershed. The samplers are located on Asotin Creek: Asotin Creek at the mouth, Asotin Creek at Koch site, and South Fork Asotin Creek above the forks. At the end of Water Year (WY) 2001 we decided to sample from Oct. 1 through June 30 of each water year. This decision was based on the difficulty of obtaining good low flow samples, since the shallow depth of water often meant that instrument intakes were on the bed of the river and samples were contaminated with bed sediments. The greatest portion of suspended sediment is transported during the higher flows of fall and especially during the spring snow runoff period, and sampling the shorter season should allow characterization of the sediment load of the river. The ISCO water samplers collected a daily composite sample of 4 samples per day into one bottle at 6-hour intervals until late March when they were reprogrammed to collect 3 samples per day at 8-hour intervals. This was done to reduce battery use since battery failure had become an ongoing problem. The water is picked up on 24-day cycles and brought to the Forest Service Water Lab in Pendleton, OR. The samples are analyzed for total suspended solids (TSS), conductivity, and turbidity. A total dissolved solids value is estimated based on conductivity. The USGS gage, Asotin Creek at the mouth, No.13335050 has been discontinued and there are no discharge records available for this period.
Date: August 1, 2003
Creator: Peterson, Stacia
Partner: UNT Libraries Government Documents Department

TESTING OF BASELINE AND LAMINATED FILTER DISKS USING MST AND MMST WITH A PILOT SCALE ROTARY FILTER

Description: Testing was completed to compare the filtration performance of modified monosodium titanate (mMST) with that of monosodium titanate (MST) with the rotary microfilter. In addition, the performance of the new laminated filter disk was compared to that of the original baseline welded filter disk. Results showed that flux rates for mMST exceeded that of MST with both the baseline and laminated filter disks in deployment concentrations of 0.2 g/L of mMST and 0.4 g/L of MST. The filtration rate of the mMST with the laminated filter disk exceeded that of the baseline filter disk. However, the baseline filter disk filtration rate for MST was greater than that of the laminated disk. The measured sample turbidity for all tests was 1.06 NTU or less. A contract was established with SpinTek Filtration{trademark} to operate a 3-disk pilot scale unit with prototypic filter disks and various feeds and two different filter disk membranes. SpinTek evaluated a set of the baseline 0.5 micron filter disks as well as a set of laminated filter disks using the same 0.5 micron filter disks. The membrane used for both disk sets was manufactured by the Pall Corporation (PMM 050). Each set of disks was run with monosodium titanate (MST) and modified monosodium titanate (mMST). Throughout the testing, samples of the filtrate were collected and measured for turbidity.
Date: December 19, 2001
Creator: Herman, D.
Partner: UNT Libraries Government Documents Department

Sediment Discharge from Highway Construction Near Port Carbon, Pennsylvannia

Description: This report examines the effects of a highway construction project on suspended-sediment loads, concluding that the construction caused sixteen-thousand tons of sediment to be discharged and produced fifty percent of the total sediment discharge. It contains tables and graphs.
Date: April 1978
Creator: Helm, Robert E.
Partner: UNT Libraries Government Documents Department

Hematological Parameters of the Bluegill, Lepomis machrochirus (Rafinesque), Including Effects of Turbidity, Chloramines, and Flexibacter columnaris

Description: Normal ranges of values for hematological parameters of bluegill gathered seasonally from three lakes were determined. Sexual, seasonal, and inter-lake variations were found. Effects of 2-wk exposure to turbidity on blood parameters included an increase in rbc size and a decrease in small lymphocytes. Effects of 3-hr exposure were increases in rbc count, hemoglobin, and pH and decreases in PG2 and large lymphocytes. The effects of 0.44 and 0.88 ppm chloramines were an increase in blood pH, a decrease in MEV, and severe spastic reactions resulting in loss of equilibrium or death in 90% of the fish. Effects of Flexibacter columnaris included an increase in transformed lymphocytes and a decrease in small lymphocytes.
Date: May 1976
Creator: Jones, Betty Juanelle
Partner: UNT Libraries

Chloride Analysis of RFSA Second Campaign Dissolver Solution

Description: The dissolver solution from the second RFSA campaign was analyzed for chloride using the recently-developed turbidimetric method. Prior to chloride removal in head end, the solution contained 1625 ppm chloride. After chloride removal with Hg(I) and prior to feeding to solvent extraction, the solution contained only 75 ppm chloride. This report discusses those analysis results.
Date: May 17, 2001
Creator: Holcomb, H.P.
Partner: UNT Libraries Government Documents Department

Removal of wax and stickies from OCC by flotation. Progress report No. 3, July 1--September 30, 1998

Description: In this quarter we completed low consistency laboratory pulping trials. Pulping results were analyzed in terms of defibering index or yield and the concentration of free wax. The objective of these trials is to identify pulping conditions that will give higher yield and higher concentration of free wax. The yields from low consistency pulping trials ranged from 90 to 99% based on 6-cut laboratory screen rejects. In general, high temperatures (140-150{degree}F) and high pH (9.5-10) conditions resulted in higher yield and the generation of free wax. Factors such as rotor speed and the gap (between the rotor and grate) were not significant in affecting defibering. Generally, the turbidities of filtrates from wax-contaminated pulps increased with increase in temperature and/or pH. The filtrate turbidity indicated the relative concentration of finely dispersed wax that could be removed from pulp dewatered on a 30 {micro}m filter paper. Preliminary experiments were conducted to study flotation conditions necessary for effective removal of wax from pulp. Factors which are important for effective flotation include flotation time, volume of air, surfactant concentration and type, and low temperature. Future plans include additional flotation trials to better optimize conditions. Other contaminant types include pressure sensitive adhesives and hot melts will also be examined. This will be followed by pilot plant and mill trials.
Date: November 1, 1998
Creator: Doshi, M.R.; Dyer, J.; Heise, O. & Cao, B.
Partner: UNT Libraries Government Documents Department

Development of a gas-promoted oil agglomeration process. Technical progress report, April 1, 1995--June 30, 1995

Description: Several scale model mixing systems have been built and are being utilized to study the gas-promoted, oil agglomeration process for cleaning coal. Numerous batch agglomeration tests have been conducted with these systems. During an individual test the progress of agglomeration has been monitored by observing either changes in agitator torque in the case of concentrated particle suspensions or changes in turbidity in the case of dilute suspensions. A mathematical model has been developed for relating the rate of agglomeration of coal particles to the rate of change of turbidity of a dilute particle suspension undergoing agglomeration. The model has been utilized for analyzing and interpreting the results of a number of oil agglomeration tests in which several different system parameters were varied.
Date: December 1, 1995
Creator: Wheelock, T.D.
Partner: UNT Libraries Government Documents Department

Groundwater Monitoring Plan for the 216-A-29 Ditch

Description: This document presents a groundwater monitoring plan, under Resource Conservation and Recovery Act of 1976 (RCRA) regulatory requirements found in WAC 173-303-400, and by reference, requirements in 40 CFR 265.93 (d)(6) for the 216-A-29 Ditch (A-29 Ditch) in the Hanford Site's 200 East Area. The objectives of this monitoring plan are to determine whether any hazardous constituents are detectable in the groundwater beneath the ditch. The groundwater monitoring network described in this plan includes 10 RCRA-compliant wells to monitor the aquifer in the immediate vicinity of the A-29 Ditch. Groundwater assessment activities have been conducted at the A-29 Ditch, the result of elevated specific conductivity and total organic halogens (TOX). A groundwater assessment report (Votava 1995) found that no hazardous constituents had impacted groundwater and the site returned to interim-status indicator-parameter/detection monitoring. This plan describes the process and quality objectives for conducting the indicator-parameter program. The site will be sampled semiannually for indicator parameters including pH, specific conductance, TOX, and total organic carbon. Site-specific parameters include tritium and ICP metals. These constituents, as well as anions, alkalinity, and turbidity will be sampled annually. Groundwater elevations will be recorded semiannually.
Date: October 7, 1999
Creator: Sweeney, M.D.
Partner: UNT Libraries Government Documents Department

Aluminum Corrosion and Turbidity

Description: Aluminum corrosion and turbidity formation in reactors correlate with fuel sheath temperature. To further substantiate this correlation, discharged fuel elements from R-3, P-2 and K-2 cycles were examined for extent of corrosion and evidence of breaking off of the oxide film. This report discusses this study.
Date: March 10, 2003
Creator: Longtin, F.B.
Partner: UNT Libraries Government Documents Department

Underwater Optical Properties of Lake Texoma (Oklahoma-Texas) Using Secchi Disk, Submarine Photometer, and High-Resolution Spectroscopy

Description: The underwater optical climate of Lake Texoma was measured at eleven fixed stations from August 1996 to August 1997. Secchi transparency and submarine photometry characterized seasonal and spatial values of secchi depth (SD), vertical attenuation coefficient (η''), and depth of euphotic zone (Zeu). Indices of Zeu:SD and η'' × SD were compared with universally applied values derived from inland and coastal waters. Turbidity explained 76% of the variation (p = 0.0001) of η'' among water quality parameters, including chlorophyll-α. Using a spectroradiometer, spectral signatures of chlorophyll-α and turbidity were located. Stations with low turbidity exhibited a distinct green reflectance peak around 590-610 nanometers, indicating presence of chlorophyll-α. Stations with high turbidity exhibited a reflectance peak shift towards the red spectrum, making it difficult to detect the chlorophyll signature. Derivative analysis of the reflectance signal at 590-610, and 720-780 nanometers allowed discrimination of this chlorophyll signature from those of turbidity (0.66 ≤ r^2 ≤ 0.99).
Date: August 1998
Creator: Rolbiecki, David A. (David Alan)
Partner: UNT Libraries

P-Area Acid/Caustic Basin groundwater monitoring report. First quarter 1995

Description: During first quarter 1995, groundwater from the six PAC monitoring wells at the P-Area Acid/Caustic Basin was analyzed for herbicides/pesticides, indicator parameters, metals, nitrate, adionuclide indicators, and other constituents. Monitoring results that exceeded the final Primary Drinking Water Standards (PDWS) or the Savannah River Site (SRS) flagging criteria or turbidity standard during the quarter are discussed in this report. During first quarter 1995, no constituents exceeded the final PDWS. Aluminum exceeded its SRS Flag 2 criterion in all six PAC wells. Iron and manganese exceeded Flag 2 criteria in three wells, while turbidity was elevated in one well. Groundwater flow direction and rate in the water table beneath the P-Area Acid/Caustic Basin were similar to past quarters.
Date: June 1, 1995
Creator: Chase, J.A.
Partner: UNT Libraries Government Documents Department

Characterization of Turbiditic Oil Reservoirs Based on Geophysical Models of Their Formation

Description: A hierarchy of models and results are presented for the simulation of the dynamics and deposition of concentrated turbidity currents. The turbidity flows are assumed to be two-dimensional due to a constant flux release of dense suspensions spreading over a nonerodible flat surface. The three models presented are the Suspension Balance Model (SBM), the Simplified Suspension Balance Model (SSBM) and the Vertically Averaged Simplified Suspension Balance Model (VASSBM). The SBM is computationally intensive. However, simulations of the SBM indicate that the only a subset of the terms in the equations for the SBM are significant. The VASSBM is significantly faster computationally, and it is shown here to be an accurate approximation of the SBM model. For all the models, the two parameters that determine the dynamics and deposition of a concentrated turbidity current due to a constant flux release are the inlet volume fraction and the buoyancy number, a ratio of the buoyancy forces to viscous forces acting on the current. A parameter study is conducted for a volume fraction ranging from 10 to 40% and buoyancy numbers ranging from 0.01 to 0.2, typical of many real concentrated turbidity flows. It is found that the length or extent of deposit is mostly determined by inlet volume fraction and is relatively insensitive to the buoyancy number. The converse, though, is found for the thickness of the deposit.
Date: April 1, 2004
Creator: Bonnecaze, Roger T. & Lakshminarasimhan, Srivatsan
Partner: UNT Libraries Government Documents Department

Characterization of Turbiditic Oil Reservoirs Based on Geophysical Models of their Formation

Description: Models are developed and solved to describe the flow of and deposition from low and high concentration turbidity currents. The shallow water equations are amended to include particle transport to describe the low concentration turbidity currents. The suspension balance model is used to describe the high concentration turbidity currents. Numerical simulations are developed to solve the highly non-linear, free boundary problems associated with these models. Simpler, algebraic scaling relationships are also developed for these models. The models are successfully validated against field observations of turbidites. With these models, one can take seismic information on the shape of the turbiditic deposit and estimate the particle size, which can be used to determine the porosity and permeability.
Date: January 15, 2006
Creator: Bonnecaze, Roger
Partner: UNT Libraries Government Documents Department

Turbulence at Hydroelectric Power Plants and its Potential Effects on Fish.

Description: The fundamental influence of fluid dynamics on aquatic organisms is receiving increasing attention among aquatic ecologists. For example, the importance of turbulence to ocean plankton has long been a subject of investigation (Peters and Redondo 1997). More recently, studies have begun to emerge that explicitly consider the effects of shear and turbulence on freshwater invertebrates (Statzner et al. 1988; Hart et al. 1996) and fishes (Pavlov et al. 1994, 1995). Hydraulic shear stress and turbulence are interdependent natural fluid phenomena that are important to fish, and consequently it is important to develop an understanding of how fish sense, react to, and perhaps utilize these phenomena under normal river flows. The appropriate reaction to turbulence may promote movement of migratory fish or prevent displacement of resident fish. It has been suggested that one of the adverse effects of flow regulation by hydroelectric projects is the reduction of normal turbulence, particularly in the headwaters of reservoirs, which can lead to disorientation and slowing of migration (Williams et al. 1996; Coutant et al. 1997; Coutant 1998). On the other hand, greatly elevated levels of shear and turbulence may be injurious to fish; injuries can range from removal of the mucous layer on the body surface to descaling to torn opercula, popped eyes, and decapitation (Neitzel et al. 2000a,b). Damaging levels of fluid stress can occur in a variety of circumstances in both natural and man-made environments. This paper discusses the effects of shear stress and turbulence on fish, with an emphasis on potentially damaging levels in man-made environments. It defines these phenomena, describes studies that have been conducted to understand their effects, and identifies gaps in our knowledge. In particular, this report reviews the available information on the levels of turbulence that can occur within hydroelectric power plants, and the associated biological effects. ...
Date: January 1, 2001
Creator: Cada, Glenn F. & Odeh, Mufeed
Partner: UNT Libraries Government Documents Department

Evaluation of the Effects of Turbulence on the Behavior of Migratory Fish, 2002 Final Report.

Description: The fundamental influence of fluid dynamics on aquatic organisms is receiving increasing attention among aquatic ecologists. For example, the importance of turbulence to ocean plankton has long been a subject of investigation (Peters and Redondo 1997). More recently, studies have begun to emerge that explicitly consider the effects of shear and turbulence on freshwater invertebrates (Statzner et al. 1988; Hart et al. 1996) and fishes (Pavlov et al. 1994, 1995). Hydraulic shear stress and turbulence are interdependent natural hydraulic phenomena that are important to fish, and consequently it is important to develop an understanding of how fish sense, react to, and perhaps utilize these phenomena under normal river flows. The appropriate reaction to turbulence may promote movement of migratory fish (Coutant 1998) or prevent displacement of resident fish. It has been suggested that one of the adverse effects of flow regulation by hydroelectric projects is the reduction of normal turbulence, particularly in the headwaters of reservoirs, which can lead to disorientation and slowing of migration (Williams et al. 1996; Coutant et al. 1997; Coutant 1998). On the other hand, greatly elevated levels of shear and turbulence may be injurious to fish; injuries can range from removal of the mucous layer on the body surface to descaling to torn opercula, popped eyes, and decapitation (Neitzel et al. 2000a,b). Damaging levels of fluid stress, such turbulence, can occur in a variety of circumstances in both natural and man-made environments. This report discusses the effects of shear stress and turbulence on fish, with an emphasis on potentially damaging levels in man-made environments. It defines these phenomena, describes studies that have been conducted to understand their effects, and identifies gaps in our knowledge. In particular, this report reviews the available information on the levels of turbulence that can occur within hydroelectric power plants, and ...
Date: March 2002
Creator: Odeh, Mufeed
Partner: UNT Libraries Government Documents Department

High concentration suspended sediment measurments using acontinuous fiber optic in-stream transmissometer

Description: Suspended sediment loads mobilized during high flow periods in rivers and streams are largely uncharacterized. In smaller and intermittent streams, a large storm may transport a majority of the annual sediment budget. Therefore monitoring techniques that can measure high suspended sediment concentrations at semi-continuous time intervals are needed. A Fiber optic In-stream Transmissometer (FIT) is presented for continuous measurement of high concentration suspended sediment in storm runoff. FIT performance and precision were demonstrated to be reasonably good for suspended sediment concentrations up to 10g/L. The FIT was compared to two commercially available turbidity devices and provided better precision and accuracy at both high and low concentrations. Both turbidity devices were unable to collect measurements at concentrations greater than 4 g/L. The FIT and turbidity measurements were sensitive to sediment particle size. Particle size dependence of transmittance and turbidity measurement poses the greatest problem for calibration to suspended sediment concentration. While the FIT was demonstrated to provide acceptable measurements of high suspended sediment concentrations, approaches to real-time suspended sediment detection need to address the particle size dependence in concentration measurements.
Date: May 26, 2004
Creator: Campbell, Chris G.; Laycak, Danny T.; Hoppes, William; Tran,Nguyen T. & Shi, Frank G.
Partner: UNT Libraries Government Documents Department

K-Area Acid/Caustic Basin groundwater monitoring report. First quarter 1995

Description: During first quarter 1995, samples from the KAC monitoring wells at the K-Area Acid/Caustic Basin were collected and analyzed for herbicides/pesticides, indicator parameters, metals, nitrate, radionuclide indicators, and other constituents. Monitoring results that exceeded the final Primary Drinking Water Standards (PDWS), other Savannah River Site (SRS) Flag 2 criteria, or the SRS turbidity standard are provided in this report. No constituents exceeded the final PDWS in the KAC wells. Aluminum and iron exceeded other SRS flagging criteria in one or more of the downgradient wells. Groundwater flow direction and rate in the water table beneath the K- Area Acid/Caustic Basin were similar to past quarters.
Date: June 1, 1995
Partner: UNT Libraries Government Documents Department

Compatibility of manufacturing process fluids with R-134a and polyolester lubricant. Final report

Description: This report includes a broad list of processing fluids that are known to be used to manufacture air conditioning and refrigeration products. Sixty-four process fluids from this list were selected for compatibility studies with R-134a and ICI EMKARATE RL32H (32 ISO) polyolester lubricant. Solutions or suspensions of the process fluid residues in polyolester lubricant were heated for 14 days at 175{degrees}C (347{degrees}F) in evacuated sealed glass tubes containing only valve steel coupons. Miscibility tests were performed at 90 wt.% R-134a, 10 wt.% polyolester lubricant with process fluid residue contaminate and were scanned in 10{degrees}C (18{degrees}F) increments over a temperature range of ambient to -40{degrees}C (-40{degrees}F). Any sign of turbidity, haze formation or oil separation was considered the immiscibility point.
Date: July 1, 1996
Creator: Cavestri, R.C. & Schooley, D.L.
Partner: UNT Libraries Government Documents Department

Characterization of Turbiditic Oil Reservoirs Based on Geophysical Models of Their Formation

Description: Two aspects of the characterization of turbiditic oil reservoirs based on geophysical models of their formation are discussed in this report. First, we have developed a new, more accurate and computationally faster finite-element method (FEM) for simulating the flow and deposition of turbidity currents. Although a finite volume method had been presented and discussed in a previous report, it was discovered to be insufficient for our purposes of simulating turbidity flows. The new method allows variable grids near the regions of large deposition, which are of most interest, and numerically results in banded, sparse matrices that are much faster to solve. Examples of the success of the method are presented. In the second part of this report, we present and discuss a preliminary study on the feasibility of matching the results of a sediment transport model to field data. With the simulation of the turbidity current we can create an entire turbiditic deposit. This requires the initial conditions of the flow, such as the amount of sediment, the volume or flow rate of the current, etc, which are of course unavailable. This requires an estimate of the initial conditions of the flow, which can be determined from limited data from the deposit. We used the Excel optimization routine Solver to reproduce a one-dimensional algebraically simulated deposit with and without measurement noise. Results indicate that such matching is feasible, provided that the noise is below certain thresholds, dependent on the size of the deposit and the number data points constraining the parameter estimation.
Date: June 1, 2003
Creator: Bonnecaze, Roger T. & Lakshminarasimhan, Srivatsan
Partner: UNT Libraries Government Documents Department

Application of advanced reservoir characterization, simulation, and production optimization strategies to maximize recovery in slope and basin clastic reservoirs, west Texas (Delaware Basin). Annual progress report, March 31, 1995--March 31, 1996

Description: The objective of this Class III project is to demonstrate that detailed reservoir characterization of clastic reservoirs in basinal sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover more of the original oil in place by strategic infill-well placement and geologically based field development. Reservoirs in the Delaware Mountain Group have low producibility (average recovery <14 percent of the original oil in place) because of a high degree of vertical and lateral heterogeneity caused by depositional processes and post-depositional diagenetic modification. Detailed correlations of the Ramsey sandstone reservoirs in Geraldine Ford field suggest that lateral sandstone continuity is less than interpreted by previous studies. The degree of lateral heterogeneity in the reservoir sandstones suggests that they were deposited by eolian-derived turbidites. According to the eolian-derived turbidite model, sand dunes migrated across the exposed shelf to the shelf break during sea-level lowstands and provided well sorted sand for turbidity currents or grain flows into the deep basin.
Date: August 1, 1996
Creator: Dutton, S.P.; Hovorka, S.D. & Cole, A.G.
Partner: UNT Libraries Government Documents Department

THE LIFETIME OF BACTERIAL MESSENGER RNA

Description: Puromycin, an inhibitor of protein synthesis, appears to act as an inhibitor at additional sites during the induction of {beta}-galactosidase synthesis. No inhibition of the reactions proceeding during the first 20 seconds of induction was observed, but puromycin seems to prevent the accumulation of messenger RNA during the period between 20 seconds and the first appearance of enzyme activity after 3 minutes. When cells from a stationary culture are placed in fresh medium containing inducer for {beta}-galactosidase, growth, as represented by increase in turbidity and by total protein synthesis, starts within 30 seconds. By contrast, {beta}-galactosidase synthesis is greatly delayed compared with induction during exponential growth. Two other inducible enzymes show similar lags, but malic dehydrogenase, which requires no external inducer, shows no lag. The lags are not due to catabolite repression phenomena. They cannot be reduced by pretreatment of the culture with inducer, or by supplementing the fresh medium with amino acids or nucleotides. The lag is also demonstrated by an i{sup -} mutant constitutive for {beta}-galactosidase synthesis. An inhibitor of RNA synthesis, 6-azauracil, preferentially inhibits {beta}-galactosidase synthesis compared with growth in both inducible and constitutive strains. It is suggested that these observations, together with many reports in the literature that inducible enzyme synthesis is more sensitive than total growth to some inhibitors and adverse growth conditions, can be explained by supposing that messenger RNA for normally inducible enzymes is biologically more labile than that for normally constitutive proteins. The implications of this hypothesis for the achievement of cell differentiation by genetic regulation of enzyme synthesis are briefly discussed.
Date: December 1, 1963
Creator: Moses, V. & Calvin, M.
Partner: UNT Libraries Government Documents Department