# Forespore engulfment during B. subtilis sporulation

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 2021 · $370,166

## Abstract

The phagocytosis-like process of engulfment is the hallmark of endospore formation in
bacteria from the genera Bacillus and Clostridium, which produce unusually durable
endospores that are the infectious agent of Anthrax and Botulism. Engulfment mediates a
dramatic change in cellular architecture, rearranging the sporangium from two cells that lie
side by side, to an endospore in which one cell (the forespore) lies within the cytoplasm of
another (the mother cell). The studies supported by this grant have provided new insights
into the mechanisms by which coordinated peptidoglycan synthesis and degradation
mediate this dramatic example of the architectural plasticity of bacterial cells, and they are
providing insight into the role essential proteins play in this process. We here propose to
visualize the dramatic morphological rearrangements of sporulation and the protein
complexes that mediate them, by using a new implementation of cryo-electron tomography
that uses a focused ion beam to produce thin lamella of bacterial cells, producing images
that reveal structures within cells at nanometer resolution. We also propose to pursue
preliminary data that has revealed that sporulation entails a dramatic and previously
unrecognized metabolic differentiation of the two cells, after which the future spore is
completely dependent on the mother cell for the precursors for biosynthesis. This process,
which appears to be mediated by a massive forespore-specific proteolysis event, effectively
converts the two cells into synthrophic partners, providing an accessible model for studying
coupled metabolism, which is prevalent in microbial communities and biofilms. We here
propose to study these processes, using genetics, metabolomics, fluorescence and cryo-
electron microscopy, integrating these experimental efforts with computational analysis and
modeling. These studies will reveal the cellular and metabolic landscape of sporulation in
unprecedented detail, capitalizing on the dispensability and streamlined machinery of
sporulation to provide insight into conserved processes that are often essential for growth.

## Key facts

- **NIH application ID:** 10085240
- **Project number:** 5R01GM057045-21
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **Principal Investigator:** Kit J Pogliano
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $370,166
- **Award type:** 5
- **Project period:** 1998-01-01 → 2023-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10085240

## Citation

> US National Institutes of Health, RePORTER application 10085240, Forespore engulfment during B. subtilis sporulation (5R01GM057045-21). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10085240. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*