RESUMEN
The type VI secretion system (T6SS) is an interbacterial weapon composed of thousands of protein subunits and predicted to require significant cellular energy to deploy, yet a fitness cost from T6SS use is rarely observed. Here, we identify host-like conditions where the T6SS incurs a fitness cost using the beneficial symbiont, Vibrio fischeri, which uses its T6SS to eliminate competitors in the natural squid host. We hypothesized that a fitness cost for the T6SS could be dependent on the cellular energetic state and used theoretical ATP cost estimates to predict when a T6SS-dependent fitness cost may be apparent. Theoretical energetic cost estimates predicted a minor relative cost for T6SS use in fast-growing populations (0.4-0.45% of total ATP used cell-1), and a higher relative cost (3.1-13.6%) for stationary phase cells. Consistent with these predictions, we observed no significant T6SS-dependent fitness cost for fast-growing populations typically used for competition assays. However, the stationary phase cell density was significantly lower in the wild-type strain, compared to a regulator mutant that does not express the T6SS, and this T6SS-dependent fitness cost was between 11 and 23%. Such a fitness cost could influence the prevalence and biogeography of T6SSs in animal-associated bacteria. While the T6SS may be required in kill or be killed scenarios, once the competitor is eliminated there is no longer selective pressure to maintain the weapon. Our findings indicate an evolved genotype lacking the T6SS would have a growth advantage over its parent, resulting in the eventual dominance of the unarmed population.
RESUMEN
Forming equity-based community-academic partnerships focused on recovery research is a time- consuming and challenging endeavor, but one well worth the care and effort required. Through building trusting relationships, vital research collaborations emerge, which are driven by expressed community needs and supported with university resources. This article describes the stakeholder engagement process utilized by a university-based and opioid-focused initiative entitled Innovations in Recovery through Infrastructure Support (IRIS). IRIS developed a diverse and representative network of clinical providers, peer recovery workers, academics, and other behavioral health leaders. The process was informed by community-based participatory research (CBPR) practices and principles aimed at creating equitable partnerships. Lessons learned include the need to reshape the relationship between research and the community through an acknowledgment of harms committed by academia, as well as the importance of maintaining an approach of humility, accountability, and patience with the partnership process. Concrete benefits that go beyond the long-term promise of change, including compensating partners financially for their time, help ensure equity. A commitment to always asking "Who's missing?" and then filling those gaps builds a broad network inclusive of the various constituencies that make up the recovery support system. As IRIS builds on these lessons learned and plans next steps, we share our experience to support others engaged in forming community-academic partnerships through deep stakeholder engagement and use of participatory approaches within and outside of recovery research.
