Implications of rRNA Operon Copy Number and Ribosome Content in the Marine Oligotrophic Ultramicrobacterium Sphingomonassp. Strain RB2256

1998 ◽  
Vol 64 (11) ◽  
pp. 4433-4438 ◽  
Author(s):  
Fitri Fegatella ◽  
Julianne Lim ◽  
Staffan Kjelleberg ◽  
Ricardo Cavicchioli
Keyword(s):  
Growth Rate ◽  
Copy Number ◽  
Heterotrophic Bacteria ◽  
Single Copy ◽  
Rrna Operon ◽  
Limiting Factor ◽  
E Coli ◽  
Rate Of Growth ◽  
Rates Of Growth ◽  
Low Rate

ABSTRACT Sphingomonas sp. strain RB2256 is a representative of the dominant class of ultramicrobacteria that are present in marine oligotrophic waters. In this study we examined the rRNA copy number and ribosome content of RB2256 to identify factors that may be associated with the relatively low rate of growth exhibited by the organism. It was found that RB2256 contains a single copy of the rRNA operon, in contrast to Vibrio spp., which contain more than eight copies. The maximum number of ribosomes per cell was observed during mid-log phase; however, this maximum content was low compared to those of faster-growing, heterotrophic bacteria (approximately 8% of the maximum ribosome content of Escherichia coli with a growth rate of 1.5 h−1). The low number of ribosomes per cell appears to correlate with the low rate of growth (0.16 to 0.18 h−1) and the presence of a single copy of the rRNA operon. However, on the basis of cell volume, RB2256 appears to have a higher concentration of ribosomes than E. coli (approximately double that of E. coli with a growth rate of 1.5 h−1). Ribosome numbers reached maximum levels during mid-log-phase growth but decreased rapidly to 10% of maximum during late log phase through 7 days of starvation. The cells in late log phase and at the onset of starvation displayed an immediate response to a sudden addition of excess glucose (3 mM). This result demonstrates that a ribosome content 10% of maximum is sufficient to allow cells to immediately respond to nutrient upshift and achieve maximum rates of growth. These data indicate that the bulk of the ribosome pool is not required for protein synthesis and that ribosomes are not the limiting factor contributing to a low rate of growth. Our findings show that the regulation of ribosome content, the number of ribosomes per cell, and growth rate responses in RB2256 are fundamentally different from those characteristics in fast-growing heterotrophs like E. coliand that they may be characteristics typical of oligotrophic ultramicrobacteria.

The Relative Growth of Parts in Palaemon Carcinus

1930 ◽  
Vol 7 (2) ◽  
pp. 165-174
Author(s):  
M. A. TAZELAAR
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Linear Measurements ◽  
Relative Growth ◽  
Male And Female ◽  
Relative Growth Rates ◽  
Rate Of Growth ◽  
The Difference ◽  
Rates Of Growth

Linear measurements of certain appendages and the carapace of P. carcinus were made and plotted in various ways. The following conclusions were drawn: 1. The cheliped shows heterogonic growth in both male and female, but more markedly in the male, the values of k being: male 1.8 and female 1.48 2. The pereiopods in both male and female are slightly heterogonic. The relative growth rates are graded from p3 to p5, that of p3 being slightly greater than that of p5 3. Of the ordinary pereiopods the rate of growth of p1 is the smallest in the male, but the largest in the female. 4. The difference between the rates of growth of p1 and p3 in male and female is greatest where the rate of growth in the heterogonic organ, the cheliped, is most excessive in the male. 5. The growth of the 3rd maxilliped is slightly negatively heterogonic, the value of k in the male being 0.93 and in the female 0.95. Hence there seems to be a correlation between the marked heterogony in the cheliped on the growth rate of neighbouring appendages. In those immediately posterior to the cheliped the growth rate is increased and in those anterior decreased.

scholarly journals THE EFFECTS OF SULFATHIAZOLE AND OF PROPYL CARBAMATE ON THE RATE OF OXYGEN CONSUMPTION AND GROWTH IN ESCHERICHIA COLI

1947 ◽  
Vol 30 (3) ◽  
pp. 263-278 ◽  
Author(s):  
Kenneth C. Fisher ◽  
Florence H. Armstrong
Keyword(s):  
Escherichia Coli ◽  
Oxygen Consumption ◽  
Cell Count ◽  
Optical Density ◽  
Viable Cell ◽  
E Coli ◽  
Rate Of Growth ◽  
A Value ◽  
Rate Of Oxygen Consumption ◽  
Rates Of Growth

1. The rates of growth and of oxygen consumption by cells of E. coli have been measured under identical conditions, and the effects of sulfathiazole (ST) and of n-propyl carbamate (PC) on these two processes have been compared. 2. The rate of growth was measured by (a) the increase in the viable cell count, (b) the increase in the optical density of the culture, (c) the increase in the rate of oxygen consumption, and (d) the decrease in the ammonia of the medium. The results as indicated by these several measures were identical under the conditions of these experiments. 3. Concentrations of ST or of PC which are just sufficient to stop growth completely, lower the rate of oxygen consumption per unit of bacterial protoplasm to a value approximately 50 per cent of that seen in the absence of the inhibitor. 4. It is shown that the rate of oxygen consumption in cells from old cultures is less affected by ST than is the rate of oxygen consumption by cells from young cultures. It is probable that the rate of oxygen consumption by "old" cells is lower than that of "young" cells. 5. The effects of ST and PC on both the rate of oxygen consumption and the rate of growth are very similar, indicating in a general way, that the mechanism of the actions of these two inhibitors is similar. Furthermore, since both of them produce appreciable inhibition of the rate of oxygen consumption while they are inhibiting growth, the possibility that the effect on oxygen consumption is the immediate cause of the effect on growth must be entertained.

scholarly journals IS103, a new insertion element in Escherichia coli: characterization and distribution in natural populations.

Genetics ◽  
1989 ◽  
Vol 121 (3) ◽  
pp. 423-431 ◽  
Author(s):  
B G Hall ◽  
L L Parker ◽  
P W Betts ◽  
R F DuBose ◽  
S A Sawyer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Copy Number ◽  
Insertion Sequence ◽  
Natural Populations ◽  
Single Copy ◽  
Target Sequence ◽  
Wild Type ◽  
Insertion Element ◽  
E Coli ◽  
Natural Isolates

Abstract IS103 is a previously unknown insertion sequence found in Escherichia coli K12. We have sequenced IS103 and find that it is a 1441-bp element that consists of a 1395-bp core flanked by imperfect 23-bp inverted repeats. IS103 causes a 6-bp duplication of the target sequence into which it inserts. There is a single copy of IS103 present in wild-type E. coli K12 strain HfrC. In strain X342 and its descendents there are two additional copies, one of which is located within the bglF gene. IS103 is capable of excising from within bglF and restoring function of that gene. IS103 exhibits 44% sequence identity with IS3, suggesting that the two insertion sequences are probably derived from a common ancestor. We have examined the distribution of IS103 in the chromosomes and plasmids of the ECOR collection of natural isolates of E. coli. IS103 is found in 36 of the 71 strains examined, and it strongly tends to inhabit plasmids rather than chromosomes. Comparison of the observed distribution of IS103 with distributions predicted by nine different models for the regulation of transposition according to copy number and of the effects of copy number on fitness suggest that transposition of IS103 is strongly regulated and that it has only minor effects on fitness. The strong clustering of IS103 within one phylogenetic subgroup of the E. coli population despite its presence on plasmids suggests that plasmids tend to remain within closely related strains and that transfer to distantly related strains is inhibited.

Section II. The forecast in detail

2003 ◽  
Vol 184 ◽  
pp. 45-57
Keyword(s):  
Growth Rate ◽  
Private Investment ◽  
Household Consumption ◽  
Consumption Expenditure ◽  
Rate Of Growth ◽  
Rates Of Growth ◽  
Trend Growth

Annual GDP in 2002 grew by 1.8 per cent as compared to a trend growth rate of about 2½ per cent. The weakness of the economy was due to falling private investment and exports. A reasonable rate of growth was sustained due to the strength of household consumption expenditure, which grew by 3.8 per cent. Our estimate of growth in the first quarter of this year of 0.3 per cent does not suggest that the economy has recovered to trend rates of growth.

scholarly journals Engineered ribosomal RNA operon copy-number variants of E. coli reveal the evolutionary trade-offs shaping rRNA operon number

2015 ◽  
Vol 43 (3) ◽  
pp. 1783-1794 ◽  
Author(s):  
Zsuzsanna Gyorfy ◽  
Gabor Draskovits ◽  
Viktor Vernyik ◽  
Frederick F. Blattner ◽  
Tamas Gaal ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Copy Number ◽  
Copy Number Variants ◽  
Rrna Operon ◽  
E Coli ◽  
Trade Offs

scholarly journals Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem

2016 ◽  
Vol 6 ◽  
Author(s):  
Jorge A. Valdivia-Anistro ◽  
Luis E. Eguiarte-Fruns ◽  
Gabriela Delgado-Sapién ◽  
Pedro Márquez-Zacarías ◽  
Jaime Gasca-Pineda ◽  
...  
Keyword(s):  
Growth Rate ◽  
Aquatic Ecosystem ◽  
Copy Number ◽  
Rrna Operon

Natural rates of growth and longevity of Nautilus belauensis

Paleobiology ◽  
1983 ◽  
Vol 9 (3) ◽  
pp. 280-288 ◽  
Author(s):  
W. Bruce Saunders
Keyword(s):  
Growth Rate ◽  
Life Span ◽  
Growth Line ◽  
Annual Increment ◽  
Mark Recapture ◽  
Rate Of Growth ◽  
Crop Content ◽  
Rates Of Growth ◽  
Mean Annual Increment ◽  
Age Estimates

Capture-mark-recapture of Nautilus belauensis in Palau shows that (a) immature animals added an average of 0.1 mm of shell per day at the ventral circumference (projected mean annual increment of 37 mm), but this rate decreases rapidly as maturity is approached; (b) rate of growth line secretion is irregular, ranging from 4 to 8 days per growth line in immature animals; (c) overall weight is an imprecise measure of size and growth in Nautilus due to fluctuations in crop content and chamber liquid; (d) this species is shown to live for at least 4 yr beyond maturity. Age estimates based on the highest growth rate obtained (0.12 mm/day = 43.8 mm/yr) range from 14.5 to 17 yr for seven animals recaptured 45–355 days after release. Combined, these data indicate that the life span of Nautilus may exceed 20 yr.

Growth of the N-type fleece.

1952 ◽  
Vol 3 (4) ◽  
pp. 435 ◽  
Author(s):  
AS Fraser
Keyword(s):  
Growth Rate ◽  
Marked Effect ◽  
Primary Effect ◽  
Rate Of Growth ◽  
Early Primary ◽  
Rates Of Growth ◽  
Second Wave

The rates of growth of wool fibres are compared between normal and N-type Romney Marsh sheep. The three types of follicles — primaries and first- and second-wave secondaries — form their fibres at rates of the same order in normal Romneys. The N and nr genes cause an increase in the rate of growth of the early, primary fibres, and a decrease in the rate of growth of late fibres, having no marked effect on fibres initiated between these two periods. It is argued that. the primary effect of these genes is to increase the efficiency of competition of the early initiated follicles, resulting in an increased growth rate of their fibres, which, owing to competition between follicles, results in a proportionate decrease in the growth rate of the late fibres.

scholarly journals Exchange of spacer regions between rRNA operons in Escherichia coli.

Genetics ◽  
1990 ◽  
Vol 125 (4) ◽  
pp. 683-690 ◽  
Author(s):  
S Harvey ◽  
C W Hill
Keyword(s):  
Escherichia Coli ◽  
Gene Conversion ◽  
Copy Number ◽  
Single Copy ◽  
The Other ◽  
Gene Conversion Event ◽  
E Coli ◽  
Coding Regions ◽  
Sister Chromatids ◽  
Rrn Operons

Abstract The Escherichia coli rRNA operons each have one of two types of spacer separating the 16S and 23S coding regions. The spacers of four operons encode tRNA(Glu2) and the other three encode both tRNA(Ile) and tRNA(Ala1B). We have prepared a series of mutants in which the spacer region of a particular rrn operon has been replaced by the opposite type. Included among these were a mutant retaining only a single copy of the tRNA(Glu2) spacer (at rrnG) and another retaining only a single copy of the tRNA(Ile)-tRNA(Ala1B) spacer (at rrnA). While both mutants grew more slowly than controls, the mutant deficient in tRNA(Glu2) spacers was more severely affected. At a frequency of 6 X 10(-5), these mutants phenotypically reverted to faster growing types by increasing the copy number of the deficient spacer. In most of these phenotypic revertants, the deficient spacer type appeared in a rrn operon which previously contained the surplus type, bringing the ratio of spacer types closer to normal. In a few cases, these spacer changes were accompanied by an inversion of the chromosomal material between the donor and recipient rrn operons. Two examples of inversion of one-half of the E. coli chromosome between rrnG and rrnH were observed. The correlation of spacer change with inversion indicated that, in these particular cases, the change was due to an intrachromatid gene conversion event accompanied by a reciprocal crossover rather than reciprocal exchange between sister chromatids.

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