ABSTRACT
It is now well established in humans that there is a bidirectional pathway of communication between the central and enteric nervous systems in which members of the microbiome participate. This microbiota-gut-brain axis (MGBA) is crucial for normal development and physiology, and its dysregulation has been implicated in a range of neurological and intestinal disorders. Investigations into the mechanistic underpinnings of the MGBA have identified serotonin as a molecule of particular interest. In this review, we highlight recent advances toward understanding the role of endogenous serotonin in microbial communities, how microbial communities bidirectionally interact with host serotonin, and potential future engineering opportunities to leverage these novel mechanisms for biomedical applications.
Subject(s)
Gastrointestinal Microbiome , Microbiota , Humans , Serotonin/metabolism , Brain-Gut Axis , Brain/metabolismABSTRACT
BACKGROUND: There is reason to expect beliefs about depression's causes and treatment to influence use of psychotherapy, but the literature is marked by theoretical, methodological, and empirical inconsistencies. This study assessed the factorial validity of measures of beliefs about depression's causes and formal treatment versus self-management. It also tested the links of causal attributions to general treatment/self-management beliefs and endorsement of specific interventions. METHODS: The revised Illness Perception Questionnaire (IPQ-R) adapted for depression was administered online to a non-patient, U.S. sample (N = 319). RESULTS: Confirmatory factor analyses yielded three causal dimensions, Environmental Stressors, Biological Factors, and Personal Attributes, and two control dimensions, (Formal) Treatment and Personal. Both models fit irrespective of whether respondents believed they had ever experienced depression. A structural equation model (SEM) showed a positive relationship for Environmental and Biological attributions, and an inverse relationship for Personal attributions, in predicting general preferences for Formal Treatment. A second SEM, focusing on specific interventions, linked Environmental causation to endorsement of psychotherapy, dietary changes, and self-help, and Biological causation to endorsement of medication and exercise, with Personal causation inversely associated with endorsement of psychotherapy. LIMITATIONS: A cross-sectional, correlational design precludes causal inferences. Potential sociocultural influences were not assessed. CONCLUSIONS: Modifications to the IPQ-R suggested by this study improved its psychometric properties, validated its distinction between Treatment and Personal Control beliefs, and supported examination of both general and specific beliefs about ways to deal with depression. Relationships linking cause and treatment beliefs warrant further investigation as potential intervention targets to increase treatment utilization.
Subject(s)
Depression , Cross-Sectional Studies , Factor Analysis, Statistical , Humans , Psychometrics , Surveys and QuestionnairesABSTRACT
Replication initiator proteins (Reps) from the HUH-endonuclease superfamily process specific single-stranded DNA (ssDNA) sequences to initiate rolling circle/hairpin replication in viruses, such as crop ravaging geminiviruses and human disease causing parvoviruses. In biotechnology contexts, Reps are the basis for HUH-tag bioconjugation and a critical adeno-associated virus genome integration tool. We solved the first co-crystal structures of Reps complexed to ssDNA, revealing a key motif for conferring sequence specificity and for anchoring a bent DNA architecture. In combination, we developed a deep sequencing cleavage assay, termed HUH-seq, to interrogate subtleties in Rep specificity and demonstrate how differences can be exploited for multiplexed HUH-tagging. Together, our insights allowed engineering of only four amino acids in a Rep chimera to predictably alter sequence specificity. These results have important implications for modulating viral infections, developing Rep-based genomic integration tools, and enabling massively parallel HUH-tag barcoding and bioconjugation applications.
Subject(s)
DNA Helicases/metabolism , DNA, Single-Stranded/metabolism , Deoxyribonuclease I/metabolism , Nucleic Acid Conformation , Protein Conformation , Protein Engineering/methods , Single-Strand Specific DNA and RNA Endonucleases/metabolism , Trans-Activators/metabolism , Viral Proteins/metabolism , Amino Acid Motifs , Amino Acid Sequence , Circoviridae/enzymology , Conserved Sequence , Crystallography, X-Ray , DNA Helicases/chemistry , DNA, Single-Stranded/chemistry , Deoxyribonuclease I/chemistry , Gene Library , Models, Molecular , Molecular Docking Simulation , Molecular Sequence Data , Plant Viruses/enzymology , Protein Binding , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Replication Origin , Sequence Alignment , Sequence Homology, Amino Acid , Single-Strand Specific DNA and RNA Endonucleases/chemistry , Substrate Specificity , Trans-Activators/chemistry , Viral Proteins/chemistryABSTRACT
The Rep domain of Wheat dwarf virus (WDV Rep) is an HUH endonuclease involved in rolling-circle replication. HUH endonucleases coordinate a metal ion to enable the nicking of a specific ssDNA sequence and the subsequent formation of an intermediate phosphotyrosine bond. This covalent protein-ssDNA adduct makes HUH endonucleases attractive fusion tags (HUH-tags) in a diverse number of biotechnological applications. Solving the structure of an HUH endonuclease in complex with ssDNA will provide critical information about ssDNA recognition and sequence specificity, thus enabling rationally engineered protein-DNA interactions that are programmable. The structure of the WDV Rep domain reported here was solved in the apo state from a crystal diffracting to 1.24â Å resolution and represents an initial step in the direction of solving the structure of a protein-ssDNA complex.
