KINRAKU

See life at micro scale: atlas, petri dish, biofilm, chemotaxis, SIR epidemics, antibiotic resistance, the tree of life. Twelve interactive simulations in one app.

KINRAKU is a visual-first educational app for microbiology, infection dynamics, and evolution.

The 13th installment in the SUUGAKU / BUTURAKU / DENRAKU / HARAKU / NETURAKU / SEIRAKU / KORAKU / RYORAKU / RYURAKU / KAKURAKU / KIKARAKU / KAGAKU series. This time the theme is "microbes, infection, and evolution." Twelve core topics from high-school to introductory-university biology, all delivered through beautiful simulations and hands-on interaction.

[12 Features]

• Microbe Atlas 17 species across Bacteria, Archaea, Eukarya, and Viruses. Tap any card for shape, size, habitat, and role.

• Cell Structure Cross-sections of all three domains. Bacterial nucleoid, plasmids, and flagellum; archaeal S-layer and ether-linked membrane; eukaryotic nucleus, mitochondria, ER, and vacuole — all labeled.

• Cell Division Binary fission, budding, and sporulation animated through one full cycle. Watch N(t) = N₀ · 2^(t/g) climb as you tune the generation time.

• Petri Dish Tap to inoculate three different microbes. Adjust nutrient, temperature, and pH to see colony growth shift and species compete where they meet.

• Biofilm Planktonic cells attach to a surface and secrete an EPS matrix to build a 3D community. Watch the four stages — attachment, microcolony, maturation, dispersal — plus quorum-sensing switching and the high drug resistance inside the matrix. Tune attachment and growth rates.

• Chemotaxis Bacteria swim toward nutrients (attractants) and away from toxins (repellents) via run-and-tumble. Move the source with a tap or drag and watch the population climb the gradient and aggregate. Tune cell count, sensitivity, and swim speed.

• Fermentation Switch between lactic acid bacteria, yeast, and koji mold. Watch the substrate fall and products (lactate / ethanol / CO₂ / enzymes) accumulate, with live pH readout.

• SIR Simulator 180 agents wander and infect each other. Real-time epidemic curve, live S/I/R/V counts, and the basic reproduction number R₀. Sliders for β, γ, mobility, and vaccination dramatically reshape outbreaks.

• World Map Metapopulation SIR over 7 Japanese regions, coupled by travel. Press lockdown to halt cross-region transmission; apply vaccination and observe herd-immunity effects.

• Immune System Macrophages follow chemotactic gradients, chase pathogens, and engulf them. Tilt the balance between immune count and pathogen growth and watch infection establish or clear.

• Resistance Evolution Three sliders: antibiotic concentration, mutation rate, growth rate. Apply pressure and watch susceptible cells die while rare resistant mutants take over — the resistance histogram shifts right as evolution unfolds.

• Tree of Life The full tree from LUCA to the three domains and major clades. Pinch to zoom across billions of years of evolution.

[Highlights]

• Formula reference sheet on every screen
• Live dynamics for SIR, logistic growth, and selection
• Japanese / English support
• Dark mode / Light mode
• Clean, intuitive UI
• Only a small banner ad at the bottom

[Recommended for]

• High-school biology and university microbiology / public-health students
• Anyone wanting to intuitively grasp epidemic models and antibiotic resistance
• Teachers looking for interactive teaching materials
• Anyone curious about how life evolved at the microscopic scale