Sulfoquinovosyl diacylglycerol is required for dimerisation of the Rhodobacter sphaeroides reaction centre-light harvesting 1 core complex.

The reaction centre-light harvesting 1 (RC-LH1) core complex is indispensable for anoxygenic photosynthesis. In the purple bacterium Rhodobacter (Rba.) sphaeroides RC-LH1 is produced both as a monomer, in which 14 LH1 subunits form a C-shaped antenna around 1 RC, and as a dimer, where 28 LH1 subunits form an S-shaped antenna surrounding 2 RCs. Alongside the five RC and LH1 subunits, an additional polypeptide known as PufX provides an interface for dimerisation and also prevents LH1 ring closure, introducing a channel for quinone exchange that is essential for photoheterotrophic growth. Structures of Rba. sphaeroides RC-LH1 complexes revealed several new components; protein-Y, which helps to form the quinone channel; protein-Z, of unknown function and seemingly unique to dimers; and a tightly bound sulfoquinovosyl diacylglycerol (SQDG) lipid that interacts with two PufX arginine residues. This lipid lies at the dimer interface alongside weak density for a second molecule, previously proposed to be an ornithine lipid. In this work we have generated strains of Rba. sphaeroides lacking protein-Y, protein-Z, SQDG or ornithine lipids to assess the roles of these previously unknown components in the assembly and activity of RC-LH1. We show that whilst the removal of either protein-Y, protein-Z or ornithine lipids has only subtle effects, SQDG is essential for the formation of RC-LH1 dimers but its absence has no functional effect on the monomeric complex.

Testing the feasibility of the QuitAid smoking cessation intervention in a randomized factorial design in an independent, rural community pharmacy.

BACKGROUND: Adult smoking rates in the USA are highest in economically depressed rural Appalachia. Pharmacist-delivered tobacco cessation support that incorporates medication therapy management (such as the QuitAid intervention) is a promising approach to address this need. METHODS: Twenty-four adult smokers recruited between September and November 2021 through an independent pharmacy in rural Appalachia were randomized in a non-blinded 2 × 2 × 2 factorial design to (1) pharmacist delivered QuitAid intervention (yes vs. no); (2) combination nicotine replacement therapy (NRT) gum + NRT patch (vs. NRT patch); and/or (3) 8 weeks of NRT (vs. standard 4 weeks). Participants received 4 weeks of NRT patch in addition to the components to which they were assigned. Participants completed baseline and 3-month follow-up assessments. Primary outcomes were feasibility of recruitment and randomization, retention, treatment adherence, and fidelity. RESULTS: Participants were recruited in 7 weeks primarily through a referral process, commonly referred to as ask-advise-connect (61%). Participants were on average 52.4 years old, 29.2% were male and the majority were white (91.6%) and Non-Hispanic (91.7%). There was a high level of adherence to the interventions, with 85% of QuitAid sessions completed, 83.3% of the patch used, and 54.5% of gum used. Participants reported a high level of satisfaction with the program, and there was a high level of retention (92%). CONCLUSIONS: This demonstration pilot randomized controlled study indicates that an ask-advise-connect model for connecting rural smokers to smoking cessation support and providing QuitAid for smoking cessation is feasible and acceptable among rural Appalachian smokers and independent pharmacists. Further investigation into the efficacy of a pharmacist-delivered approach for smoking cessation is needed. TRIAL REGISTRATION: The trial was retrospectively registered at ClinicalTrials.gov. Trial #: NCT05649241.

Rationale, design, and methods for the development of a youth adapted Brief Tobacco Intervention plus automated text messaging for high school students.

BACKGROUND: Tobacco use is increasing among youth in the U.S. The current study seeks to develop and pilot test a universal group-based Youth Brief Tobacco Intervention (Y-BTI) plus mobile phone automated text messaging (ATM) for 9th grade students to both prevent initiation among non-users and promote cessation among current users. METHODS: This study will use a sequential, multi-method research design beginning with mixed methods formative work with 9th grade students to adapt the existing young adult Brief Tobacco Intervention (BTI) for youth and develop automated text messages. The formative work with students will identify salient themes and strategies for the interventions and optimal delivery schedules for the ATM intervention. The second phase of the study evaluates the Y-BTI and ATM through a pilot cluster randomized controlled trial that compares four treatment combinations: (1) Y-BTI + ATM, (2) Y-BTI alone, (3) ATM alone, or (4) standard of care. The Y-BTI is a single session, group-based intervention delivered in schools. The ATM intervention will provide comparable content to the Y-BTI but be delivered via text messaging 3-5 times per week for four weeks. CONCLUSION: In order to curb the rise of tobacco use among youth, interventions that are easily implemented and disseminated need to be developed. We aim to build upon previous research by showing that a universal group-based Y-BTI and ATM are effective in reducing tobacco use among a 9th graders by preventing initiation among tobacco naïve youth and promoting cessation among current users.