scholarly journals Positive Growth Rate-Dependent Regulation of the pdxA, ksgA, and pdxB Genes of Escherichia coli K-12

2002 ◽  
Vol 184 (5) ◽  
pp. 1359-1369 ◽  
Author(s):  
Andrew J. Pease ◽  
Benjamin R. Roa ◽  
Wen Luo ◽  
Malcolm E. Winkler
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Growth Rates ◽  
Protein Accumulation ◽  
Rate Regulation ◽  
Specific Transcript ◽  
Positive Growth ◽  
Positive Growth Rate ◽  
K 12 ◽  
Per Gene

ABSTRACT We found that transcription of the pdxA and pdxB genes, which mediate steps in the biosynthesis of the essential coenzyme pyridoxal 5"-phosphate, and the ksgA gene, which encodes an rRNA modification enzyme and is partly cotranscribed with pdxA, is subject to positive growth rate regulation in Escherichia coli K-12. The amounts of the pdxA-ksgA cotranscript and pdxB- and ksgA-specific transcripts and expression from pdxA- and pdxB-lacZ fusions increased as the growth rate increased. The half-lives of ksgA- and pdxB-specific transcripts were not affected by the growth rate, whereas the half-life of the pdxA-ksgA cotranscript was too short to be measured accurately. A method of normalization was applied to determine the amount of mRNA synthesized per gene and the rate of protein accumulation per gene. Normalization removed an apparent anomaly at fast growth rates and demonstrated that positive regulation of pdxB occurs at the level of transcription initiation over the whole range of growth rates tested. RNA polymerase limitation and autoregulation could not account for the positive growth rate regulation of pdxA, pdxB, and ksgA transcription. On the other hand, growth rate regulation of the amount of the pdxA-ksgA cotranscript was abolished by a fis mutation, suggesting a role for the Fis protein. In contrast, the fis mutation had no effect on pdxB- or ksgA-specific transcript amounts. The amounts of the pdxA-ksgA cotranscript and ksgA-specific transcript were repressed in the presence of high intracellular concentrations of guanosine tetraphosphate; however, this effect was independent of relA function for the pdxA-ksgA cotranscript. Amounts of the pdxB-specific transcript remained unchanged during amino acid starvation in wild-type and relA mutant strains.

scholarly journals Growth in demand and supply of pulses in India-A normative approach

2016 ◽  
Vol 8 (4) ◽  
pp. 1756-1761
Author(s):  
P. D. Shivagangavva ◽  
B. S. Reddy
Keyword(s):  
Growth Rate ◽  
Significant Influence ◽  
Growth Rates ◽  
Narrow Gap ◽  
Lower Growth ◽  
Demand And Supply ◽  
Significant Growth ◽  
Normative Approach ◽  
Positive Growth ◽  
Positive Growth Rate

The changing scenario of consumption and production of pulses will have significant influence on the demand- supply prospects of pulses in India. The country as whole, production of redgram had increased marginally (0.45%) during 1980-2012(Overall study period), though there is positive and significant growth in production(2.86%) during 1980-90 (Period-I), mainly due to lower growth during 1991-2012(period-II). The significant growth in production (1.39%) and productivity (1.04%) of bengalgram in the entire period except area (0.35%) was observed. However, growth in greengram production (1.14%) and productivity (1.21%) was found almost similar. In case of blackgram, positive growth rate in area, productivity and production in both the periods have ultimately resulted higher growth rates in the overall period. The growth in total pulses production indicated that growth in area (-0.10%) was negative while it was positive both in production (1.49%) and productivity (1.59%) during period-I. Similar pattern of growth was observed during period-II and in the overall study period. The estimated demand for pulses were 183.62 lakh tonnes over supply of 148.66 lakh tonnes indicating deficit of 34.96 lakh tonnes during 2001 –2011. Further, demand for pulses expected to reach 225.36 and 255.16 lakh tonnes in the year 2020 and 2030 respectively. Whereas, supply of pulses will reach 218.50 and 237.00 lakh tonnes in the same period indicating narrow gap between demand and supply in the future.

scholarly journals Initiation and Velocity of Chromosome Replication in Escherichia coli B/r and K-12

1998 ◽  
Vol 180 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Meeshel Bipatnath ◽  
Patrick P. Dennis ◽  
Hans Bremer
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Growth Rates ◽  
Cell Mass ◽  
Chromosome Replication ◽  
Chromosomal Replication ◽  
Copy Numbers ◽  
Identical Manner ◽  
Time Required ◽  
K 12

ABSTRACT The macromolecular composition and a number of parameters affecting chromosome replication were examined over a range of exponential growth rates in two common Escherichia coli strains, B/r and K-12 AB1157. Based on improved measurements of DNA after treatment of exponential cultures with rifampin, the cell mass per chromosomal replication origin (initiation mass) and the time required to replicate the chromosome from origin to terminus (C period) were determined. For these two strains, the initiation mass approached values of 8 × 10−10 and 10 × 10−10 units of optical density (at 460 nm) of culture mass per oriC, respectively, at growth rates above 1 doubling/h (at 37°C). The amount of protein per oriC decreased with increasing growth rate for AB1157 and remained nearly constant for the B/r strain. The C period decreased for both strains in an essentially identical manner from about 70 min at 0.6 doublings/h to about 33 min at 3 doublings/h. From the initiation mass andC period, relative or absolute copy numbers for genes with known map locations can be accurately determined at different growth rates. At growth rates above 2 doublings/h, when chromosomes are highly branched, genes near the origin are about threefold more prevalent than genes near the terminus. At a growth rate of 0.6 doubling/h, this ratio is only about 1.7, which reflects the lower degree of chromosome branching.

scholarly journals Escherichia colipopulations adapt to complex, unpredictable fluctuations without any trade-offs across environments

2016 ◽  
Author(s):  
Shraddha Karve ◽  
Devika Bhave ◽  
Dhanashri Nevgi ◽  
Sutirth Dey
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Growth Rates ◽  
Complex Environments ◽  
Multiple Stresses ◽  
Trade Off ◽  
Trade Offs ◽  
Fluctuating Environments ◽  
Laboratory Populations ◽  
Lower Variation

AbstractIn nature, organisms are simultaneously exposed to multiple stresses (i.e. complex environments) that often fluctuate unpredictably. While both these factors have been studied in isolation, the interaction of the two remains poorly explored. To address this issue, we selected laboratory populations ofEscherichia coliunder complex (i.e. stressful combinations of pH, H2O2and NaCl) unpredictably fluctuating environments for ~900 generations. We compared the growth rates and the corresponding trade-off patterns of these populations to those that were selected under constant values of the component stresses (i.e. pH, H2O2and NaCl) for the same duration. The fluctuation-selected populations had greater mean growth rate and lower variation for growth rate over all the selection environments experienced. However, while the populations selected under constant stresses experienced severe tradeoffs in many of the environments other than those in which they were selected, the fluctuation-selected populations could by-pass the across-environment trade-offs completely. Interestingly, trade-offs were found between growth rates and carrying capacities. The results suggest that complexity and fluctuations can strongly affect the underlying trade-off structure in evolving populations.

scholarly journals The Growth Performance of Selected Spice Crops in Haryana State

2021 ◽  
Vol 14 (3) ◽  
pp. 346-357
Author(s):  
Choote Lal ◽  
Rohtas Kait
Keyword(s):  
Growth Rate ◽  
Growth Performance ◽  
Productivity Growth ◽  
Secondary Data ◽  
The State ◽  
Descriptive Statistics ◽  
Kharif Season ◽  
Significant Growth ◽  
Positive Growth ◽  
Positive Growth Rate

Abstract Subject and purpose of work: The study aims to evaluate the growth performance of spice crops in Haryana state of India. Materials and methods: The study is based on secondary data obtained over the period of 17 years i.e., from 2001-2002 to 2017-2018. Four spice crop – ginger, turmeric, garlic and fenugreek were selected from rabi and kharif season on the basis of the largest area sown. In order to analyze the data descriptive statistics (mean and C.V.) and CGR (compound growth rate) were employed. Results: T he s tudy r evealed a significant p ositive g rowth r ate o f 2.20%, 4.50% and 2.20% in the area, production and productivity of ginger in the district of Panchkula, respectively. In the district of Yamunanagar, a growth rate 13.80% and 10.20% was found in the area and production of turmeric. However, a negative productivity growth rate of -3.20% was also revealed. A positive growth rate 1.50%, 3.30% and 0.17% was found in the area, production and productivity of garlic in Karnal district. In the district of Yamunanagar, a growth rate for fenugreek of 7.30% and 7.60% and 13.90% in the area, production and productivity was found. The state of Haryana recorded a significant growth of 1.7%, 2.8% and 1.1% per annum in the area, production and productivity of spice crops respectively. Conclusions: T he s tudy r evealed a positive g rowth rate across all the selected spice crops, indicating improving prospects of spice crops in Haryana state.

scholarly journals Molecular Control of Sucrose Utilization in Escherichia coli W, an Efficient Sucrose-Utilizing Strain

2012 ◽  
Vol 79 (2) ◽  
pp. 478-487 ◽  
Author(s):  
Suriana Sabri ◽  
Lars K. Nielsen ◽  
Claudia E. Vickers
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Good Growth ◽  
Knockout Mutant ◽  
Sucrose Transport ◽  
Molecular Control ◽  
Content Type ◽  
E Coli ◽  
K 12 ◽  
Sucrose Utilization

ABSTRACTSucrose is an industrially important carbon source for microbial fermentation. Sucrose utilization inEscherichia coli, however, is poorly understood, and most industrial strains cannot utilize sucrose. The roles of the chromosomally encoded sucrose catabolism (csc) genes inE. coliW were examined by knockout and overexpression experiments. At low sucrose concentrations, thecscgenes are repressed and cells cannot grow. Removal of either the repressor protein (cscR) or the fructokinase (cscK) gene facilitated derepression. Furthermore, combinatorial knockout ofcscRandcscKconferred an improved growth rate on low sucrose. The invertase (cscA) and sucrose transporter (cscB) genes are essential for sucrose catabolism inE. coliW, demonstrating that no other genes can provide sucrose transport or inversion activities. However,cscKis not essential for sucrose utilization. Fructose is excreted into the medium by thecscK-knockout strain in the presence of high sucrose, whereas at low sucrose (when carbon availability is limiting), fructose is utilized by the cell. Overexpression ofcscA,cscAK, orcscABcould complement the WΔcscRKABknockout mutant or confer growth on a K-12 strain which could not naturally utilize sucrose. However, phenotypic stability and relatively good growth rates were observed in the K-12 strain only when overexpressingcscAB, and full growth rate complementation in WΔcscRKABalso requiredcscAB. Our understanding of sucrose utilization can be used to improveE. coliW and engineer sucrose utilization in strains which do not naturally utilize sucrose, allowing substitution of sucrose for other, less desirable carbon sources in industrial fermentations.

scholarly journals Rapid Growth of UropathogenicEscherichia coliduring Human Urinary Tract Infection

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Valerie S. Forsyth ◽  
Chelsie E. Armbruster ◽  
Sara N. Smith ◽  
Ali Pirani ◽  
A. Cody Springman ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Urinary Tract ◽  
Growth Rates ◽  
High Growth ◽  
Replication Forks ◽  
Chromosomal Replication ◽  
E Coli ◽  
Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These strains are a subgroup of extraintestinal pathogenicE. coli(ExPEC) strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than otherE. coliisolates and survive in that niche. To date, there has not been a reliable method available to measure their growth ratein vivo. Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR), a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robustin vivo, matching or exceedingin vitrogrowth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi). In contrast, asymptomatic bacteriuria (ABU) strains tended to maintain high growth ratesin vivoat 6, 24, and 30 hpi, and population densities did not increase, suggesting that host responses or elimination limited population growth. Fecal strains displayed moderate growth rates at 6 hpi but did not survive to later times. By PTR,E. coliin urine of human patients with UTIs displayed extraordinarily rapid growth during active infection, with a mean doubling time of 22.4 min. Thus, in addition to traditional virulence determinants, including adhesins, toxins, iron acquisition, and motility, very high growth ratesin vivoand resistance to the innate immune response appear to be critical phenotypes of UPEC strains.IMPORTANCEUropathogenicEscherichia coli(UPEC) strains cause most urinary tract infections in otherwise healthy women. While we understand numerous virulence factors are utilized byE. colito colonize and persist within the urinary tract, these properties are inconsequential unless bacteria can divide rapidly and survive the host immune response. To determine the contribution of growth rate to successful colonization and persistence, we employed two methods: one involving the segregation of a nonreplicating plasmid in bacteria as they divide and the peak-to-trough ratio, a sequencing-based method that enumerates chromosomal replication forks present during cell division. We found that UPEC strains divide extraordinarily rapidly during human UTIs. These techniques will be broadly applicable to measurein vivogrowth rates of other bacterial pathogens during host colonization.

scholarly journals Adaptation in a Mouse Colony Monoassociated with Escherichia coli K-12 for More than 1,000 Days

2010 ◽  
Vol 76 (14) ◽  
pp. 4655-4663 ◽  
Author(s):  
Sean M. Lee ◽  
Aaron Wyse ◽  
Aaron Lesher ◽  
Mary Lou Everett ◽  
Linda Lou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rates ◽  
Bacterial Species ◽  
Intestinal Flora ◽  
Average Density ◽  
Host Bacterium ◽  
E Coli ◽  
K 12

ABSTRACT Although mice associated with a single bacterial species have been used to provide a simple model for analysis of host-bacteria relationships, bacteria have been shown to display adaptability when grown in a variety of novel environments. In this study, changes associated with the host-bacterium relationship in mice monoassociated with Escherichia coli K-12 over a period of 1,031 days were evaluated. After 80 days, phenotypic diversification of E. coli was observed, with the colonizing bacteria having a broader distribution of growth rates in the laboratory than the parent E. coli. After 1,031 days, which included three generations of mice and an estimated 20,000 generations of E. coli, the initially homogeneous bacteria colonizing the mice had evolved to have widely different growth rates on agar, a potential decrease in tendency for spontaneous lysis in vivo, and an increased tendency for spontaneous lysis in vitro. Importantly, mice at the end of the experiment were colonized at an average density of bacteria that was more than 3-fold greater than mice colonized on day 80. Evaluation of selected isolates on day 1,031 revealed unique restriction endonuclease patterns and differences between isolates in expression of more than 10% of the proteins identified by two-dimensional electrophoresis, suggesting complex changes underlying the evolution of diversity during the experiment. These results suggest that monoassociated mice might be used as a tool for characterizing niches occupied by the intestinal flora and potentially as a method of targeting the evolution of bacteria for applications in biotechnology.

scholarly journals Temporal and Spatial Production Price Behaviour of Marketed Rapeseed-mustard in Rajasthan

2021 ◽  
pp. 151-160
Author(s):  
Kailash Chand Bairwa ◽  
Uma Nath Shukla ◽  
Harkesh Kumar Balai ◽  
Anju Yadav ◽  
Prahlad Ram Raiger ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Performance ◽  
Growth Analysis ◽  
Behavioural Change ◽  
Spatial Production ◽  
Positive Growth ◽  
Positive Rate ◽  
Positive Growth Rate ◽  
Temporal And Spatial ◽  
Very High

The present study has been carried out with the objectives of examining growth performance of area and production of rapeseed-mustard along with behavioural change in price and arrivals of rapeseed-mustard in major districts of Rajasthan. The study period from 2010-11 to 2019-20 was selected for growth analysis and January, 2011 to December, 2020 selected for study of price and arrivals of rapeseed-mustard. The results shown that production of rapeseed-mustard was increased at positive rate and area at negative in Alwar and Sawai Madhopur districts. In case of Bharatpur, the area and production of rapeseed-mustard was reported positive growth rate. The instability in annual arrivals of rapeseed-mustard was recorded very high in KUMS, Alwar and KUMS, Dig as compared to KUMS, Nagar and KUMS, Sawai Madhopur. In case of prices, the variability in all selected Krishi Upaj Mandi Samities were record in mid-range. Highlights: Highest arrivals instability was reported in Krishi Upaj Mandi Samiti, Alwar The production of rapeseed-mustard was showed positive growth rate in Rajasthan.

scholarly journals Analysis Growth Rate in Area, Production and Productivity of Sapota in Gujarat, India

2021 ◽  
pp. 31-40
Author(s):  
Tushar Pakwar ◽  
Ashok Kumar Koshariya ◽  
Kedar Vijaykumar Swami ◽  
Alpesh K. Leua
Keyword(s):  
Growth Rate ◽  
Sampling Design ◽  
Primary Data ◽  
Maintenance Cost ◽  
Positive Trend ◽  
Interview Method ◽  
Net Returns ◽  
Multi Stage ◽  
Positive Growth ◽  
Positive Growth Rate

The present investigation was "Analysis growth rate in area, production and productivity of Sapota in Gujarat". A multi stage random sampling design was used for selecting the sample. The study covered 2 Districts, 2 talukas, 12 villages and 120 Sapota growers from Valsad and Navsari districts. The primary data were collected for the season of 2011-2012 by personal interview method. In the results revealed that the Valsad and Navsari districts were found to having positive growth rate in area and production (0.20 and 0.73 per cent and 1.59 and 2.30 per cent, respectively). While the productivity of both the districts was positive viz., 0.54 and 0.70 respectively. On the contrary, a lower but positive and significant growth rate was observed in sapota area for the state as a whole, whereas the production and yield showed positive trend (2.01 and 2.55 respectively).  The per hectare total cost of establishment for four year were Rs. 75387.59 for the orchards in Valsad district and Rs. 74025.27 for the orchards in Navsari district. The maintenance cost worked out to be as Rs. 56326.59 and   Rs. 55298.27 in Valsad and Navsari district respectively. The average per ha yield from Valsad district was 10. 61 tonnes and from Navsari district was 11.11 tonnes in 6th year and net returns were Rs. 113527 from Valsad district and Rs. 118877 from Navsari district.

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