doubling time

(noun)

The doubling time is the period of time required for a quantity to double in size or value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things which tend to grow over time.

Related Terms

Examples of doubling time in the following topics:

  • Generation Time

    • Therefore, "local doubling" of the bacterial population occurs.
    • The doubling time is the generation time of the bacteria.
    • If growth is not limited, doubling will continue at a constant rate so both the number of cells and the rate of population increase doubles with each consecutive time period.
    • Death of cells as a function of time is rather unpredictable and very difficult to explain.
    • Note the Y-axis scale is logarithmic meaning that the number represents doubling.

  • Anammox

    • The bacteria mediating this process were identified in 1999, and at the time were a great surprise to the scientific community.
    • The doubling time is nearly two weeks.

  • The Energetics of Chemolithotrophy

    • Chemolithotrophic growth could be dramatically fast, such as Thiomicrospira crunogena with a doubling time around one hour.

  • Enrichment and Isolation

    • Exponential phase (sometimes called the log or logarithmic phase) is a period characterized by cell doubling.
    • The number of new bacteria appearing per unit time is proportional to the present population.Under controlled conditions, cyanobacteria can double their population four times a day.

  • Supercoiling

    • In a "relaxed" double-helical segment of B-DNA, the two strands twist around the helical axis once every 10.4 to 10.5 base pairs of sequence.
    • The twist is the number of helical turns in the DNA and the writhe is the number of times the double helix crosses over on itself (these are the supercoils).
    • Because the length of DNA can be thousands of times that of a cell, packaging this genetic material into the cell or nucleus (in eukaryotes) is a difficult feat.
    • This fiber is further coiled into a 30 nm fiber, and further coiled upon itself numerous times more.

  • Multiplex and Real-Time PCR

    • Multiplex and real-time PCR are molecular techniques designed to amplify nucleic acid sequences in a quantitative manner.
    • The PCR process can be divided into three steps: DNA denaturation where double-stranded DNA (dsDNA) is separated at temperatures above 90°C, oligonucleotide primers annealing at 50–60°C, and primer extension at 70–78°C.
    • Real-time polymerase chain (RT-PCR) reaction, also called quantitative real-time PCR (qRt-PCR) is used to amplify and quantify targeted DNA molecules.
    • Real-time PCR can used to amplify low-abundance DNA templates.
    • Two common methods that are used to product detection in real-time PCR include the use of non-specific flourescent dyes that intercalate with double-stranded DNA or sequence-specific DNA probes that consist of oligonucleotides labeled with a fluorescent reporter (oligoprobes).

  • Mu: A Double-Stranded Transposable DNA Bacteriophage

    • In this mechanism, the donor and receptor DNA sequences form a characteristic intermediate "theta" configuration, sometimes called a "Shapiro intermediate. " Replicative transposition is characteristic to retrotransposons and occurs from time to time in class II transposons.

  • Temperate Bacteriophages: Lambda and P1

    • In the viral particle it is in the form of a linear double-stranded DNA molecule.
    • The head contains the phage's double-stranded circular DNA genome.
    • Usually, a "lytic cycle" ensues, where the lambda DNA is replicated many times and the genes for head, tail, and lysis proteins are expressed.
    • The head contains 48,490 base pairs of double-stranded, linear DNA, with 12-base single-stranded segments at both 5' ends.

  • Amplifying DNA: The Polymerase Chain Reaction

    • The temperatures used, and the length of time they are applied in each cycle, depend on a variety of parameters.
    • Under optimum conditions (i.e., if there are no limitations due to limiting substrates or reagents) at each extension step, the amount of DNA target is doubled, leading to exponential (geometric) amplification of the specific DNA fragment.
    • The two resulting DNA strands make up the template DNA for the next cycle, thus doubling the amount of DNA duplicated for each new cycle.

  • DNA Analysis Using Genetic Probes and PCR

    • Hybridization of the sequence with a complementary sequence of DNA or RNA, follows cleavage of the double-stranded DNA of the microorganism in the specimen.
    • Fingerprinting technique requires high-quality genomic DNA, which is not only difficult to prepare but also requires culturing of the organism, resulting in a long turnaround time.
    • In contrast, nucleic acid amplification-based assays do not require culturing of the organisms, allowing the analysis of samples in real time.