pathmodel 0.1.5

Ab initio pathway inference

PathModel: metabolic pathway drift prototype

PathModel is a prototype to infer new biochemical reactions and new metabolite structures. The biological motivation for developing it is described in this preprint , now in revision at iScience.

There is no guarantee that this script will work, it is a Work In Progress in early state.

Table of contents

• Installation

  • Requirements

  • Using conda environment (to install all dependencies)

  • Using conda package

  • Using docker

  • Using git

  • Using pip

• Description

  • Input data

  • Use

  • Output data

  • Example

Installation

Requirements

PathModel is a Python3 package using Answer Set Programming (ASP) to infer new biochemical reactions and new metabolites structures. It is divided in two parts:

• a wrapper (pathmodel_wrapper.py) for the ASP programs (MZComputation.lp, ReactionSiteExtraction.lp and PathModel.lp).

• a plotting script (molecule_creation.py) to create pictures of molecules and pathways.

PathModel requires:

• clingo: which must be installed with Lua compatibility (a good way to have it is with conda).

• clyngor package.

• networkx (with graphviz and pygraphviz).

• matplotlib packages

• rdkit package

Using conda environment (to install all dependencies)

Due to all the dependencies required by all the script of Pathmodel, we create a conda environment file that contains all dependencies.

First you need Conda. To avoid conflict between the conda python and your system python, you could use a conda environment and Miniconda.

If you want to test this, the first thing is to install miniconda:

# Download Miniconda
wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh

# Give the permission to the installer.
chmod +x Miniconda3-latest-Linux-x86_64.sh

# Install it at the path that you choose.
./Miniconda3-latest-Linux-x86_64.sh -p /path/where/miniconda/will/be/installed/ -b

# Delete installer.
rm Miniconda3-latest-Linux-x86_64.sh

# Add conda path to you bash settings.
echo '. /path/where/miniconda/is/installed/etc/profile.d/conda.sh' >> ~/.bashrc
# Will activate the environment.
# For more information: https://github.com/conda/conda/blob/master/CHANGELOG.md#440-2017-12-20
echo 'conda activate base' >> ~/.bashrc

After this you need to restart your terminal or use: source ~/.bashrc

Then you will get our conda environment file:

# Download our conda environment file from Pathmodel github page.
wget https://raw.githubusercontent.com/pathmodel/pathmodel/master/conda/pathmodel_env.yaml

# Use the file to create the environment and install all dependencies.
conda env create -f pathmodel.yaml

If no error occurs, you can now access a conda environment with pathmodel:

# Activate the environment.
conda activate pathmodel

# Launch the help of Pathmodel.
(pathmodel) pathmodel -h

You can exit the environment with:

# Deactivate the environment.
conda deactivate

Using conda package

It will be possible to install pathmodel (and its dependencies) with a conda install. But you have to add some channels.

# Install pathmodel
conda install pathmodel -c dyliss -c anaconda -c conda-forge -c rdkit -c potassco

Using docker

A docker image of pathmodel is available at dockerhub.

docker run -ti -v /path/shared/container:/shared --name="mycontainer" pathmodel/pathmodel bash

This command will download the image and create a container with a shared path. It will launch a bash terminal where you can use the command pathmodel (see Use and Example).

Using git

The package can be installed either using python setup or pip install (see below)

git clone https://github.com/pathmodel/pathmodel.git

cd PathModel

python setup.py install

Using pip

If you have all the dependencies on your system, you can just download Pathmodel using pip.

pip install pathmodel

Description

PathModel is developed in ASP. It is divided in three ASP scripts.

The first one, ReactionSiteExtraction.lp creates reaction site.

When a reaction is described between two molecules, the script will compare atoms and bonds of the two molecules of the reaction and will extract a reaction site before the reaction (composed of atoms and bonds that are present in the reactant but absent in the product) and a reaction site after the reaction (composed of atoms and bonds present in the product but absent in the reactant).

ReactionSiteExtraction produces two sites for each reaction (one before and one after the reaction).

A second script, MZComputation.lp will compute the MZ for each known molecule.

These data will be used by the third script: PathModel.lp.

PathModel will use two inference methods: one creating new metabolites and one infering a reaction between two metabolites.

Input data

Molecules are modelled with atoms (hydrogen excluded) and bonds (single and double).

atom("Molecule1",1,carb). atom("Molecule1",2,carb).
bond("Molecule1",single,1,2).

atom("Molecule2",1,carb). atom("Molecule2",2,carb). atom("Molecule2",3,carb).
bond("Molecule2",single,1,2). bond("Molecule2",single,2,3).

Reaction between molecules are represented as link between two molecules with a name:

reaction(reaction1,"Molecule1","Molecule2").

A common domain is needed to find which molecules share structure with others:

atomDomain(commonDomainName,1,carb). atomDomain(commonDomainName,2,carb).
bondDomain(commonDomainName,single,1,2).

A molecule source is defined:

source("Molecule1").

Initiation and goal of the incremental grounding must be defined:

init(pathway("Molecule1","Molecule2")).
goal(pathway("Molecule1","Molecule3")).

M/Z ratio can be added to check whether there is a metabolite that can be predict with this ratio. M/Z ratio must be multiplied by 10 000 because Clingo doesn’t use decimals.

mzfiltering(2702720).

Molecules that are not in the organism of study can be added. They will not be targeted of the inference methods.

absentmolecules("Molecule1").

Use

Command-line:

pathmodel -d data.lp

In python:

import pathmodel

pathmodel.pathmodel_analysis('data.lp')

Output data

Using networkx, inferred pathways are represented as png picture. Also a result.lp file is created containing all the inferred reactions.

Example

The folder data/ contains example for sterols and mycosporine-like amino-acids pathways.

By calling the command:

pathmodel --example

A run of pathmodel will be launched on the sterol data. It will create a folder named pathmodel_example in the directory where you have launched the command.

In this folder, three files will be created:

-sterol_pwy.lp: containing the input data.

-inferred_sterol.lp: the inferred reactions.

-inferred_sterol.png: a png file showing the inferred reactions.

Also, the folder test/test_data/ contains an example with fictional molecules to test PathModel.