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Annual Review of Biophysics 2015Single-cell techniques have a long history of unveiling fundamental paradigms in biology. Recent improvements in the throughput, resolution, and availability of... (Review)
Review
Single-cell techniques have a long history of unveiling fundamental paradigms in biology. Recent improvements in the throughput, resolution, and availability of microfluidics, computational power, and genetically encoded fluorescence have led to a modern renaissance in microbial physiology. This resurgence in research activity has offered new perspectives on physiological processes such as growth, cell cycle, and cell size of model organisms such as Escherichia coli. We expect these single-cell techniques, coupled with the molecular revolution of biology's recent half-century, to continue illuminating unforeseen processes and patterns in microorganisms, the bedrock of biological science. In this article we review major open questions in single-cell physiology, provide a brief introduction to the techniques for scientists of diverse backgrounds, and highlight some pervasive issues and their solutions.
Topics: Animals; Cell Physiological Phenomena; Escherichia coli; Microfluidics; Single-Cell Analysis
PubMed: 25747591
DOI: 10.1146/annurev-biophys-060414-034236 -
Current Opinion in Endocrinology,... Apr 2021Ghrelin was discovered in 1999; extensive research and clinical studies on ghrelin have been published in the last 20 years. Physiological research on ghrelin ranges... (Review)
Review
PURPOSE OF REVIEW
Ghrelin was discovered in 1999; extensive research and clinical studies on ghrelin have been published in the last 20 years. Physiological research on ghrelin ranges from its appetite-stimulating effects to its association with energy homeostasis. The physiological effects of ghrelin in the gastrointestinal tract and its relevance in the pathological conditions of the gastrointestinal tract have gradually become clearer. The purpose of the review is to provide current information on ghrelin cell biology and physiology, particularly in the gastrointestinal tract.
RECENT FINDINGS
Ghrelin-producing cells in the stomach are characterized as X/A-like cells, but immunohistochemical analyses have revealed co-expression of several secreted proteins and hormones in ghrelin-producing cells such as nesfatin-1, somatostatin, and pancreastatin. Furthermore, the local physiological roles and/or mechanisms of ghrelin in gastrointestinal functions such as gastric motility and inflammation are discussed.
SUMMARY
Ghrelin is a brain-gut hormone with a wide range of physiological actions; hence, it is important to understand its effects on the physiological functions of the gastrointestinal tract to elucidate the biological significance of ghrelin.
Topics: Appetite; Cell Physiological Phenomena; Gastrointestinal Tract; Ghrelin; Humans; Stomach
PubMed: 33394720
DOI: 10.1097/MED.0000000000000610 -
American Journal of Physiology. Cell... Feb 2023
Topics: United States; Cell Physiological Phenomena; Physiology
PubMed: 36645665
DOI: 10.1152/ajpcell.00009.2023 -
American Journal of Physiology. Cell... Dec 2021The major transmembrane protein of the red blood cell, known as band 3, AE1, and SLC4A1, has two main functions: ) catalysis of Cl/[Formula: see text] exchange, one of... (Review)
Review
The major transmembrane protein of the red blood cell, known as band 3, AE1, and SLC4A1, has two main functions: ) catalysis of Cl/[Formula: see text] exchange, one of the steps in CO excretion, and ) anchoring the membrane skeleton. This review summarizes the 150-year history of research on red cell anion transport and band 3 as an experimental system for studying membrane protein structure and ion transport mechanisms. Important early findings were that red cell Cl transport is a tightly coupled 1:1 exchange and band 3 is labeled by stilbenesulfonate derivatives that inhibit anion transport. Biochemical studies showed that the protein is dimeric or tetrameric (paired dimers) and that there is one stilbenedisulfonate binding site per subunit of the dimer. Transport kinetics and inhibitor characteristics supported the idea that the transporter acts by an alternating access mechanism with intrinsic asymmetry. The sequence of band 3 cDNA provided a framework for detailed study of protein topology and amino acid residues important for transport. The identification of genetic variants produced insights into the roles of band 3 in red cell abnormalities and distal renal tubular acidosis. The publication of the membrane domain crystal structure made it possible to propose concrete molecular models of transport. Future research directions include improving our understanding of the transport mechanism at the molecular level and of the integrative relationships among band 3, hemoglobin, carbonic anhydrase, and gradients (both transmembrane and subcellular) of [Formula: see text], Cl, O, CO, pH, and nitric oxide (NO) metabolites during pulmonary and systemic capillary gas exchange.
Topics: Animals; Anion Exchange Protein 1, Erythrocyte; Cell Membrane; Cell Physiological Phenomena; Erythrocytes; Humans; Ion Transport; Membrane Transport Proteins
PubMed: 34669510
DOI: 10.1152/ajpcell.00275.2021 -
American Journal of Physiology. Cell... Mar 2024Ketogenic diets (KDs), fasting, or prolonged physical activity elevate serum ketone bodies (KBs) levels, providing an alternative fuel source for the brain and other... (Review)
Review
Ketogenic diets (KDs), fasting, or prolonged physical activity elevate serum ketone bodies (KBs) levels, providing an alternative fuel source for the brain and other organs. However, KBs play pleiotropic roles that go beyond their role in energy production. KBs can act as signaling metabolites, influence gene expression, proteins' posttranslational modifications (PTMs), inflammation, and oxidative stress. Here, we explore the impact of KBs on mammalian cell physiology, including aging and tissue regeneration. We also concentrate on KBs and cancer, given the extensive evidence that dietary approaches inducing ketosis, including fasting-mimicking diets (FMDs) and KDs, can prevent cancer and affect tumor progression.
Topics: Animals; Humans; Ketone Bodies; Neoplasms; Brain; Oxidative Stress; Cell Physiological Phenomena; Mammals
PubMed: 38189128
DOI: 10.1152/ajpcell.00441.2023 -
American Journal of Physiology. Cell... Apr 2023"I don't know the question, but sex is definitely the answer!," was a Woody Allen quote cited by Fuller and Insel in an Editorial Comment in 2013 on the importance of... (Review)
Review
"I don't know the question, but sex is definitely the answer!," was a Woody Allen quote cited by Fuller and Insel in an Editorial Comment in 2013 on the importance of cell sex in submissions to , and in biomedical research in general. The notion that cell sex is important is axiomatic in studies on prostate cancer (LnCAP) or placental physiology (BeWo). Indeed, most researchers are aware that HeLa cells are female cervical derived, and CHO are female hamster ovary cells, yet beyond those well-known examples, it would be fair to assume that the sex of cells derived from kidney, lung, or liver, for example, is given cursory, if any thought. In the end, what possible impact could the presence or absence of a Y chromosome have on protein trafficking in a nonreproductive tissue, such as a pancreatic β cell? However, this approach to cell, and indeed organismal physiology, seems to be in conflict with accumulating data, that show that far from being irrelevant, genes expressed off sex chromosomes have a broad-ranging impact on cells as diverse as neurons and renal cells. Moreover, it is also the policy of that the source of all cells used (species, sex, etc.) should be clearly indicated when submitting an article for publication (https://journals.physiology.org/author-info.manuscript-composition). In 2013, we wrote a review examining how faithfully such requirements were adhered to in submissions to . Nearly a decade later, it seems fitting to revisit the topic and ask if any improvements have been made in the description of cells and cell lines used in publications submitted to .
Topics: Pregnancy; Male; Humans; Female; HeLa Cells; Placenta; Kidney; Lung; Cell Physiological Phenomena
PubMed: 36717097
DOI: 10.1152/ajpcell.00434.2022 -
Annual Review of Biomedical Data Science Aug 2022Modern biology and biomedicine are undergoing a big data explosion, needing advanced computational algorithms to extract mechanistic insights on the physiological state... (Review)
Review
Modern biology and biomedicine are undergoing a big data explosion, needing advanced computational algorithms to extract mechanistic insights on the physiological state of living cells. We present the motivation for the Cell Physiome Project: a framework and approach for creating, sharing, and using biophysics-based computational models of single-cell physiology. Using examples in calcium signaling, bioenergetics, and endosomal trafficking, we highlight the need for spatially detailed, biophysics-based computational models to uncover new mechanisms underlying cell biology. We review progress and challenges to date toward creating cell physiome models. We then introduce bond graphs as an efficient way to create cell physiome models that integrate chemical, mechanical, electromagnetic, and thermal processes while maintaining mass and energy balance. Bond graphs enhance modularization and reusability of computational models of cells at scale. We conclude with a look forward at steps that will help fully realize this exciting new field of mechanistic biomedical data science.
Topics: Biophysics; Cell Physiological Phenomena; Models, Biological; Patient-Specific Modeling
PubMed: 35576556
DOI: 10.1146/annurev-biodatasci-072018-021246 -
Molecular Aspects of Medicine 2003
Review
Topics: Animals; Apoptosis; Biological Transport; Cell Division; Cell Physiological Phenomena; Ion Channels; Magnesium; Membrane Proteins; Oxidation-Reduction; Protein Kinases; Signal Transduction; TRPM Cation Channels
PubMed: 12537986
DOI: 10.1016/s0098-2997(02)00088-2 -
Nature Jan 2010The ability of a eukaryotic cell to resist deformation, to transport intracellular cargo and to change shape during movement depends on the cytoskeleton, an... (Review)
Review
The ability of a eukaryotic cell to resist deformation, to transport intracellular cargo and to change shape during movement depends on the cytoskeleton, an interconnected network of filamentous polymers and regulatory proteins. Recent work has demonstrated that both internal and external physical forces can act through the cytoskeleton to affect local mechanical properties and cellular behaviour. Attention is now focused on how cytoskeletal networks generate, transmit and respond to mechanical signals over both short and long timescales. An important insight emerging from this work is that long-lived cytoskeletal structures may act as epigenetic determinants of cell shape, function and fate.
Topics: Animals; Biomechanical Phenomena; Cell Physiological Phenomena; Cell Shape; Cytoskeleton; Epigenesis, Genetic; Humans
PubMed: 20110992
DOI: 10.1038/nature08908 -
Gerontology 2020Aging results for the immune system in a departure from the optimal homeostatic state seen in young organisms. This divergence regrettably contributes to a higher... (Review)
Review
Aging results for the immune system in a departure from the optimal homeostatic state seen in young organisms. This divergence regrettably contributes to a higher frequency of compromised responses to infections and inefficient classical vaccination in aged populations. In B cells, the cornerstone of humoral immunity, the development and distribution of the various mature B cell subsets are impacted by aging in both humans and mice. In addition, aged mature B cells demonstrate limited capacity to mount efficient antibody responses. An expected culprit for the decline in effective immunity is the rise of the systemic levels of pro-inflammatory molecules during aging, establishing a chronic low-grade inflammation. Indeed, numerous alterations affecting directly or indirectly B cells in old people and mice are reminiscent of various effects of acute inflammation on this cell type in young adults. The present mini-review will highlight the possible adverse contributions of the persistent low-level inflammation observed in susceptible older organisms to the inadequate B-cell physiology.
Topics: Aged; Aging; Animals; B-Lymphocytes; Cell Physiological Phenomena; Humans; Immune System; Inflammation; Mice
PubMed: 31553969
DOI: 10.1159/000501963