The PshX subunit of the photochemical reaction center from Heliobacterium modesticaldum acts as a low-energy antenna.

The anoxygenic phototrophic bacterium Heliobacterium modesticaldum contains a photochemical reaction center protein complex (called the HbRC) consisting of a homodimer of the PshA polypeptide and two copies of a newly discovered polypeptide called PshX, which is a single transmembrane helix that binds two bacteriochlorophyll g molecules. To assess the function of PshX, we produced a ∆pshX strain of Hbt. modesticaldum by leveraging the endogenous Hbt.

Deletion of the cytochrome bc complex from Heliobacterium modesticaldum results in viable but non-phototrophic cells.

The heliobacteria, a family of anoxygenic phototrophs, possess the simplest known photosynthetic apparatus. Although they are photoheterotrophs in the light, the heliobacteria can also grow chemotrophically via pyruvate metabolism in the dark. In the heliobacteria, the cytochrome bc complex is responsible for oxidizing menaquinol and reducing cytochrome c in the electron flow cycle used for phototrophy.

Using the Endogenous CRISPR-Cas System of To Delete the Photochemical Reaction Center Core Subunit Gene.

In , as in many , deleting genes by homologous recombination using standard techniques has been extremely difficult. The cells tend to integrate the introduced plasmid into the chromosome by a single recombination event rather than perform the double recombination required to replace the targeted locus. Transformation with a vector containing only a homologous recombination template for replacement of the photochemical reaction center gene produced colonies with multiple genotypes, rather than a clean gene replacement.

A Molecular Biology Tool Kit for the Phototrophic Firmicute Heliobacterium modesticaldum.

The heliobacteria are members of the bacterial order and form the only group of phototrophs in the phylum Several physiological and metabolic characteristics make them an interesting subject of investigation, including their minimalist photosynthetic system, nitrogen fixation abilities, and ability to reduce toxic metals. While the species is an excellent candidate as a model system for the family , since an annotated genome and transcriptomes are available, studies in this organism have been hampered by the lack of genetic tools. We adapted techniques for genetic manipulation of related clostridial species for use with Five heliobacterial DNA methyltransferase genes were expressed in an strain engineered as a conjugative plasmid donor for broad-host-range plasmids.

Light-driven quinone reduction in heliobacterial membranes.

Photosynthetic reaction centers (RCs) evolved > 3 billion years ago and have diverged into Type II RCs reducing quinones and Type I RCs reducing soluble acceptors via iron-sulfur clusters. Photosystem I (PSI), the exemplar Type I RC, uses modified menaquinones as intermediate electron transfer cofactors, but it has been controversial if the Type I RC of heliobacteria (HbRC) uses its two bound menaquinones in the same way. The sequence of the quinone-binding site in PSI is not conserved in the HbRC, and the recently solved crystal structure of the HbRC does not reveal a quinone in the analogous site.

Double reduction of plastoquinone to plastoquinol in photosystem 1.

In Photosystem 1 (PS1), phylloquinone (PhQ) acts as a secondary electron acceptor from chlorophyll ec(3) and also as an electron donor to the iron-sulfur cluster F(X). PS1 possesses two virtually equivalent branches of electron transfer (ET) cofactors from P(700) to F(X), and the lifetime of the semiquinone intermediate displays biphasic kinetics, reflecting ET along the two different branches. PhQ in PS1 serves only as an intermediate in ET and is not normally fully reduced to the quinol form.

The association between guideline-based treatment instructions at the point of discharge and lower 1-year mortality in Medicare patients after acute myocardial infarction: the American College of Cardiology's Guidelines Applied in Practice (GAP) initiative in Michigan.

Background: The American College of Cardiology's Guidelines Applied in Practice (GAP) initiative for acute myocardial infarction (AMI) has been shown to increase the use of guideline-based therapies and improve outcomes in patients with AMI. It is unknown whether hospitals that are more successful in using the standard discharge contract--a key component of GAP that emphasizes guideline-based medications, lifestyle modification, and follow-up planning--experience a proportionally greater improvement in patient outcomes.

Methods: Medicare patients treated for AMI in all 33 participating GAP hospitals in Michigan were enrolled.

Sex differences in the application of evidence-based therapies for the treatment of acute myocardial infarction: the American College of Cardiology's Guidelines Applied in Practice projects in Michigan.

Background: Studies have shown that women with acute myocardial infarction (AMI) are less likely to receive evidence-based care compared with men. The American College of Cardiology's AMI Guidelines Applied in Practice (GAP) program has been shown to increase the rates of evidence-based medicine use and reduce mortality in patients with AMI. The objective of this study was to investigate the relative benefits of the GAP program in men and women.

Guideline-based standardized care is associated with substantially lower mortality in medicare patients with acute myocardial infarction: the American College of Cardiology's Guidelines Applied in Practice (GAP) Projects in Michigan.

Objectives: We sought to assess the impact of the American College of Cardiology's Guidelines Applied in Practice (GAP) project for acute myocardial infarction (AMI) care, encompassing 33 acute-care hospitals in southeastern Michigan, on rates of mortality in Medicare patients treated in Michigan.

Background: The GAP project increases the use of evidence-based therapies in patients with AMI. It is unknown whether GAP also can reduce the rate of mortality in patients with AMI.

Improved quality of stroke care for hospitalized Medicare beneficiaries in Michigan.

Background And Purpose: We reported previously that acute ischemic stroke patients encountered delays in obtaining neuroimaging and receiving thrombolysis, and that deep venous thrombosis prophylaxis was used only in a minority of eligible patients. We investigated whether these and other measures improved after a quality improvement initiative.

Methods: Medicare fee-for-service ischemic stroke and transient ischemic attack discharges in 136 acute care hospitals in Michigan were identified by International Classification of Diseases, 9th Revision, Clinical Modification codes.

Differences in quality of care among patients hospitalized with atrial fibrillation as primary or secondary cause for admission.

Objective: Several factors have been linked to the variation in the quality of care for patients with atrial fibrillation (AF). Whether hospitalization primarily for AF (primary diagnosis of AF) as opposed to another primary diagnosis but having concomitant AF (secondary diagnosis of AF) impacts quality of care for AF is not known. Accordingly, we sought to evaluate the differences in quality of care of Medicare patients admitted with primary diagnosis versus secondary diagnosis of AF.

Enhancing quality of care for acute myocardial infarction: shifting the focus of improvement from key indicators to process of care and tool use: the American College of Cardiology Acute Myocardial Infarction Guidelines Applied in Practice Project in Michigan: Flint and Saginaw Expansion.

Objectives: This project evaluated if by focusing on process changes and tool use rather than key indicator rates, the use of evidence-based therapies in patients with acute myocardial infarction (AMI) would increase.

Background: The use of tools designed to improve quality of care in the American College of Cardiology AMI Guidelines Applied in Practice Pilot Project resulted in improved adherence to evidence-based therapies for patients, but overall, tool use was modest.

Methods: The current project, implemented in five hospitals, was modeled after the previous project, but with greater emphasis on tool use.

Acute ischemic stroke in hospitalized medicare patients: evaluation and treatment.

Background And Purpose: This study describes several quality indicators of care in hospitalized stroke patients in Michigan from 1998 to 1999.

Summary Of Report: Median times from admission to head CT/MRI (89.5 minutes) and thrombolysis (113 minutes) exceeded recommended guidelines.

A rapid-cycle collaborative model to promote guidelines for acute myocardial infarction.

Background: This American College of Cardiology (ACC) Acute Myocardial Infarction (AMI) Guidelines Applied in Practice (GAP) collaborative in Michigan represented ACC's third initiative, in partnership with local health care coalitions and the Michigan Peer Review Organization. The GAP Pilot Project formed the basis for this project, which supported caregivers' efforts to improve their processes and consistently apply the evidence-based guidelines for AMI care.

The Southeast Michigan Expansion Project: The Institute for Healthcare Improvement (IHI) Breakthrough Series model of improvement was modified to merge the GAP Pilot Project's design with a rapid-cycle quality improvement model.

Taking the national guideline for care of acute myocardial infarction to the bedside: developing the guideline applied in practice (GAP) initiative in Southeast Michigan.

Background: The Guideline Applied in Practice (GAP) program was developed in 2000 to improve the quality of care by improving adherence to clinical practice guidelines. For the first GAP project, the American College of Cardiology (ACC) partnered with the Southeast Michigan Quality Forum Cardiovascular Subgroup and the Michigan Peer Review Organization (MPRO) to develop interventions that might facilitate the use of the ACC/AHA Acute Myocardial Infarction (AMI) guideline in the practice setting. Ten Michigan hospitals participated in implementing the project, which began in March 2000.