Combining in vivo and in vitro approaches to better understand host-pathogen nutritional interactions

Nutrition often shapes the outcome of host-parasite interactions, however understanding the mechanisms by which this occurs is often confounded by the intimate nature of the association and by the fact that the host and parasite may compete for the same limiting nutrients. One way of disentangling this interaction is to combine in vivo and in vitro approaches. Here, we explore the role of host nutrition in determining the outcome of infections using a model insect-bacterium system: the cotton leafworm Spodoptera littoralis and the blood-borne bacterium Xenorhabdus nematophila. S. littoralis larvae were reared on one of a series of 20 chemically-defined diets ranging in their protein:carbohydrate (P:C) ratio and caloric density. They were then challenged with either a fixed dose of X. nematophila cells (live or dead) or were sham-injected. Survivorship of larvae challenged with live bacterial cells was strongly dependent on the protein levels of the diet, with mortality being highest on ..., , , # Combining in vivo and in vitro approaches to better understand host-pathogen nutritional interactions

[https://doi.org/10.5061/dryad.pzgmsbcxv](https://doi.org/10.5061/dryad.pzgmsbcxv)

## Description of the data and file structure

This was a lab-based study. The data were analysed using R. The datasets compare growth of Xenorhabdus bacteria in vivo (Spodoptera littoralis larvae) and in vitro (synthetic insect blood).

### Files and variables

#### File: BacGro4\_archive.csv

**Description:**  This file contains the data required to compare bacteriall growth in vitro versus in vivo (see Figure 4 of the paper)

##### Variables

* Diet.no: Diet number: 1-20
* Plate: Microtitre plate number
* Max.OD: Maximum optical density at 600 nm
* P2C: Protein : Carbohydate (g)
* P2C.ratio: Protein : Carbohydate (1:5 to 5:1)
* Conc: Concentration of the digestible diet
* prop.Prot.x: Proportion of protein in diet (P/P+C)
* pc.Prot: Percentage of protein in diet (P/P+C) (%)
* pc.Carb: Percentage of...