R: Data from heavy metal mixture experiments

metals {drc} | R Documentation

## Data from heavy metal mixture experiments

### Description

Data are from a study of the response of the cyanobacterial self-luminescent metallothionein-based whole-cell biosensor Synechoccocus elongatus PCC 7942 pBG2120 to binary mixtures of 6 heavy metals (Zn, Cu, Cd, Ag, Co and Hg).

### Usage

    data("metals")

### Format

A data frame with 543 observations on the following 3 variables.

`metal`

  a factor with levels `Ag` `AgCd` `Cd` `Co` `CoAg` `CoCd` `Cu` `CuAg` `CuCd` `CuCo` `CuHg` `CuZn` `Hg` `HgCd` `HgCo` `Zn` `ZnAg` `ZnCd` `ZnCo` `ZnHg`

`conc`

  a numeric vector of concentrations

`BIF`

  a numeric vector of luminescence induction factors

### Details

Data are from the study described by Martin-Betancor et al. (2015).

### Source

Martin-Betancor, K. and Ritz, C. and Fernandez-Pinas, F. and Leganes, F. and Rodea-Palomares, I. (2015) Defining an additivity framework for mixture research in inducible whole-cell biosensors, Scientific Reports 17200.

### Examples

    ## One example from the paper by Martin-Betancor et al (2015)

    ## Figure 2

    ## Fitting a model for "Zn"
    Zn.lgau <- drm(BIF ~ conc, data = subset(metals, metal == "Zn"),
    fct = lgaussian(), bcVal = 0, bcAdd = 10)

    ## Plotting data and fitted curve
    plot(Zn.lgau, log = "", type = "all",
    xlab = expression(paste(plain("Zn")^plain("2+"), " ", mu, "", plain("M"))))

    ## Calculating effective doses
    ED(Zn.lgau, 50, interval = "delta")
    ED(Zn.lgau, -50, interval = "delta", bound = FALSE)
    ED(Zn.lgau, 99.999,interval = "delta")  # approx. for ED0

    ## Fitting a model for "Cu"
    Cu.lgau <- drm(BIF ~ conc, data = subset(metals, metal == "Cu"),
    fct = lgaussian())

    ## Fitting a model for the mixture Cu-Zn
    CuZn.lgau <- drm(BIF ~ conc, data = subset(metals, metal == "CuZn"),
    fct = lgaussian())

    ## Calculating effects needed for the FA-CI plot
    CuZn.effects <- CIcompX(0.015, list(CuZn.lgau, Cu.lgau, Zn.lgau),
    c(-5, -10, -20, -30, -40, -50, -60, -70, -80, -90, -99, 99, 90, 80, 70, 60, 50, 40, 30, 20, 10))

    ## Reproducing the FA-cI plot shown in Figure 5d
    plotFACI(CuZn.effects, "ED", ylim = c(0.8, 1.6), showPoints = TRUE)

[Package drc version 3.0-1 Index]