aiming-lab/autoresearchclaw/flux-analyzer

Claude Code and agent skill by aiming-lab/autoresearchclaw

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Analyse FBA flux distributions to extract biological insights. Covers gene essentiality, phenotypic phase planes, flux sampling, pathway-level aggregation, secretion product prediction, and production of publication- quality figures.

Install

npx vskill@latest install aiming-lab/autoresearchclaw/flux-analyzer

SKILL.md

Overview

The flux-analyzer skill transforms raw FBA output into actionable biological knowledge. It operates on FBA result files and the COBRApy model to produce gene essentiality maps, phenotypic phase planes (PPP), flux sampling distributions, pathway-level summaries, and product secretion profiles.

This skill is the metabolic-modelling analogue of event reconstruction and phenomenology summary stage in the ColliderAgent pipeline: it turns numbers into biology.


Workflow

Step 1 — Load Model and FBA Results
python
import cobra
import cobra.io
import cobra.flux_analysis
import cobra.sampling
import pandas as pd
import numpy as np
import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
model = cobra.io.load_json_model("my_model.json")
fba_fluxes = pd.read_csv("fba_fluxes.csv", index_col=0)["flux_mmol_gDW_h"]
wt_growth = model.optimize().objective_value
print(f"Wild-type growth: {wt_growth:.4f} h^-1")
Step 2 — Gene Essentiality Analysis

Essential genes are those whose deletion reduces growth to below 5% of wild-type — a widely used lethality criterion.

python
from cobra.flux_analysis import single_gene_deletion, double_gene_deletion
# --- Single gene essentiality ---
sg_deletion = single_gene_deletion(model)
sg_deletion.columns = ["growth", "status"]
sg_deletion["is_essential"] = sg_deletion["growth"] < 0.05 * wt_growth
sg_deletion["growth_fraction"] = sg_deletion["growth"] / wt_growth
essential_genes = sg_deletion[sg_deletion["is_essential"]]
print(f"Essential genes: {len(essential_genes)} / {len(model.genes)}")
sg_deletion.to_csv("gene_essentiality.csv")
# --- Double gene essentiality (synthetic lethality) ---
# Limit to a focused gene set to reduce compute time
target_genes = list(model.genes)[:50] # adjust as needed
dg_deletion = double_gene_deletion(model, target_genes, target_genes)
dg_deletion.columns = ["growth", "status"]
dg_deletion["is_synthetic_lethal"] = dg_deletion["growth"] < 0.05 * wt_growth
dg_deletion.to_csv("double_gene_essentiality.csv")
Step 3 — Reaction Essentiality Analysis
python
from cobra.flux_analysis import single_reaction_deletion
sr_deletion = single_reaction_deletion(model)
sr_deletion.columns = ["growth", "status"]
sr_deletion["is_essential"] = sr_deletion["growth"] < 0.05 * wt_growth
essential_rxns = sr_deletion[sr_deletion["is_essential"]]
print(f"Essential reactions: {len(essential_rxns)} / {len(model.reactions)}")
sr_deletion.to_csv("reaction_essentiality.csv")
Step 4 — Phenotypic Phase Plane (PPP)

The PPP maps growth rate over a 2D grid of two nutrient uptake rates, revealing metabolic phase transitions (aerobic growth, mixed-acid fermentation, etc.).

python
from cobra.flux_analysis import production_envelope
# Phase plane: glucose uptake vs. oxygen uptake
ppp = production_envelope(
model,
["EX_glc__D_e", "EX_o2_e"], # x and y axes
objective=model.reactions.get_by_id("BIOMASS_Ec_iJO1366_core_53p95M"),
points=20,
)
print(ppp.head())
# Plot heatmap
fig, ax = plt.subplots(figsize=(8, 6))
pivot = ppp.pivot_table(
index="EX_o2_e", columns="EX_glc__D_e", values="flux_maximum"
)
im = ax.imshow(pivot.values, aspect="auto", origin="lower",
cmap="viridis",
extent=[ppp["EX_glc__D_e"].min(), ppp["EX_glc__D_e"].max(),
ppp["EX_o2_e"].min(), ppp["EX_o2_e"].max()])
plt.colorbar(im, ax=ax, label="Growth rate (h$^{-1}$)")
ax.set_xlabel("Glucose uptake (mmol/gDW/h)")
ax.set_ylabel("O$_2$ uptake (mmol/gDW/h)")
ax.set_title("Phenotypic Phase Plane")
fig.tight_layout()
fig.savefig("phenotypic_phase_plane.pdf", dpi=300)
fig.savefig("phenotypic_phase_plane.png", dpi=150)
plt.close(fig)
print("PPP saved to phenotypic_phase_plane.pdf")
Step 5 — Flux Sampling

Flux sampling explores the full space of feasible steady-state flux distributions, revealing which reactions have wide vs. narrow feasible ranges.

python
# OptGP sampler: Markov-chain Monte Carlo in flux cone
samples = cobra.sampling.sample(model, n=1000, method="optgp",
thinning=100, processes=4)
# samples is a DataFrame: rows = samples, columns = reaction IDs
samples.to_csv("flux_samples.csv", index=False)
# Violin plot for key central metabolism reactions
KEY_REACTIONS = ["PFK", "PGI", "PDH", "CS", "AKGDH",
"EX_glc__D_e", "EX_ac_e", "EX_co2_e"]
key_data = samples[[r for r in KEY_REACTIONS if r in samples.columns]]
fig, ax = plt.subplots(figsize=(10, 5))
ax.violinplot([key_data[c].values for c in key_data.columns],
positions=range(len(key_data.columns)),
showmedians=True)
ax.set_xticks(range(len(key_data.columns)))
ax.set_xticklabels(key_data.columns, rotation=45, ha="right")
ax.set_ylabel("Flux (mmol/gDW/h)")
ax.set_title("Flux Sampling Distribution (n=1000)")
fig.tight_layout()
fig.savefig("flux_sampling_violin.pdf", dpi=300)
plt.close(fig)
print("Flux sampling violin plot saved.")
Step 6 — Pathway-Level Flux Aggregation

Group reactions by metabolic subsystem and compute total absolute flux per pathway — a proxy for pathway activity.

python
pathway_flux = {}
for rxn in model.reactions:
subsystem = rxn.subsystem or "Unknown"
flux_val = abs(fba_fluxes.get(rxn.id, 0.0))
pathway_flux[subsystem] = pathway_flux.get(subsystem, 0.0) + flux_val
pathway_df = (pd.Series(pathway_flux, name="total_abs_flux")
.sort_values(ascending=False)
.reset_index()
.rename(columns={"index": "subsystem"}))
pathway_df.to_csv("pathway_flux_summary.csv", index=False)
# Bar chart of top 15 pathways
top15 = pathway_df.head(15)
fig, ax = plt.subplots(figsize=(10, 6))
ax.barh(top15["subsystem"][::-1], top15["total_abs_flux"][::-1],
color="steelblue")
ax.set_xlabel("Sum of |flux| (mmol/gDW/h)")
ax.set_title("Top 15 Pathway Activities (FBA)")
fig.tight_layout()
fig.savefig("pathway_activity.pdf", dpi=300)
plt.close(fig)
print("Pathway activity chart saved.")
Step 7 — Secretion Product Prediction

Identify exchange reactions carrying positive flux (secretion) at optimal growth — these are by-products and potential products of interest.

python
secretion = {}
for rxn in model.exchanges:
flux = fba_fluxes.get(rxn.id, 0.0)
if flux > 1e-6: # positive = secretion
met = list(rxn.metabolites)[0]
secretion[rxn.id] = {
"metabolite": met.name,
"formula": met.formula,
"flux_mmol_gDW_h": flux,
}
sec_df = pd.DataFrame(secretion).T.sort_values("flux_mmol_gDW_h",
ascending=False)
print("\nSecreted products:")
print(sec_df.to_string())
sec_df.to_csv("secretion_profile.csv")

Key Conventions

AnalysisLethality ThresholdStandard Reference
Single gene deletiongrowth < 5% WTJoyce & Palsson, 2006
Double gene deletion (synthetic lethal)growth < 5% WTDeutscher et al., 2008
Reaction deletiongrowth < 5% WTConsistent with gene deletion
PPP nutrient grid0–20 mmol/gDW/h, 50 stepsCOBRApy default
Flux sampling (OptGP)n = 1000, thinning = 100Megchelenbrink et al., 2014
Output File Conventions
FileContent
gene_essentiality.csvPer-gene growth fraction and essentiality flag
double_gene_essentiality.csvPairwise synthetic lethality matrix
reaction_essentiality.csvPer-reaction growth fraction and essentiality flag
phenotypic_phase_plane.pdf2D heatmap of growth vs. two nutrients
flux_samples.csvRaw 1000-sample flux matrix
flux_sampling_violin.pdfViolin plot of key reaction distributions
pathway_flux_summary.csvTotal absolute flux per metabolic subsystem
pathway_activity.pdfBar chart of top 15 active pathways
secretion_profile.csvAll secreted by-products at optimal growth
Common Failure Modes
  • PPP returns all zeros: objective reaction ID does not match model; check

model.objective.expression for correct reaction ID.

  • Flux sampling ACHR crashes: optgp (default) is more stable for large

models; for models with >5000 reactions use processes=1 to debug.

  • No secretion products: model may be forced to be strictly aerobic with

all carbon converted to CO2; verify exchange bounds allow secretion (ub = 1000 on exchange reactions).

Security

  • Security scanPassed, 95 of 100Pattern checks on the skill's files.
  • Model reviewPassed

Quality evaluation

  • Task evaluationNot runNo evaluation yet. Run one in Skill Studio.

Source

Popularity

Repository stars
14,030
Repository forks
1,639
7-day trend score
48

Stars and forks are for the whole GitHub repository, not this skill alone. Refreshed 15 Aug 2026, 2 months ago.

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