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. Author manuscript; available in PMC: 2017 Nov 9.
Published in final edited form as: Nat Microbiol. 2017 Apr 25;2:17026. doi: 10.1038/nmicrobiol.2017.26

Figure 4. Mechanisms of inter-bacterial cooperation and antagonism among Bacteroides.

Figure 4

a, Outer membrane vesicles. OMVs are generated and released by Bacteroides both in vitro and in vivo. They can act as carriers of public goods, including Sus-like components, small molecule (SM) cofactors, anti-inflammatory capsule components, such as PSA, antimicrobial (AM) proteins, such as BSAP-1, and other enzymes (Enz). Outer membrane vesicles are indicated by (1) in the inset. b, Bacteroidetes type VI secretion systems. The bacterial T6SS is a contractile molecular lancet that rapidly delivers toxic effector proteins into neighbouring cells in a manner dependent on cell-to-cell contact. The outer tube, which consists of TssB/TssC multimers in a high-energy state, contracts to a low-energy state that forces the rigid inner tube, composed of Hcp multimers, out of the donor cell and into a nearby recipient cell. The needle tip can carry bound effector proteins that mediate cell damage and death in susceptible recipient cells lacking cognate immunity proteins. The Bacteroidetes T6SS lacks a subset of components found in Proteobacterial T6SSs, and carries novel components of unknown function or structure (not depicted). IM, inner membrane; OM, outer membrane. The T6SS is indicated by (2) in the inset.