Modern Cell Biology Research Articles

Andrew S. Reynolds, The third lens: metaphor and the creation of modern cell biology, Chicago: the Chicago University Press, 2018.

Andrew S. Reynolds, The third lens: metaphor and the creation of modern cell biology, Chicago: the Chicago University Press, 2018.

Ribozyme activity modulates the physical properties of RNA-peptide coacervates.

Condensed coacervate phases are now understood to be important features of modern cell biology, as well as valuable protocellular models in origin-of-life studies and synthetic biology. In each of these fields, the development of model systems with varied and tuneable material properties is of great importance for replicating properties of life. Here, we develop a ligase ribozyme system capable of concatenating short RNA fragments into long chains. Our results show that the formation of coacervate microdroplets with the ligase ribozyme and poly(L-lysine) enhances ribozyme rate and yield, which in turn increases the length of the anionic polymer component of the system and imparts specific physical properties to the droplets. Droplets containing active ribozyme sequences resist growth, do not wet or spread on unpassivated surfaces, and exhibit reduced transfer of RNA between droplets when compared to controls containing inactive sequences. These altered behaviours, which stem from RNA sequence and catalytic activity, constitute a specific phenotype and potential fitness advantage, opening the door to selection and evolution experiments based on a genotype-phenotype linkage.

Функціональна активність гемопоетичних клітин-попередників кордової крові у довготривалій культурі на гідрогелевій підложці in vitro

Development of new and improvement of existing models of long-term cultivation of hematopoietic stem cells (HSC) and cord blood progenitor cells is one of the most important directions in modern cell biology, related to obtaining a sufficient amount of hematopoietic tissue for experimental and clinical use. The aim of the work was to investigate the functional activity of hematopoietic progenitor cells from cord blood during long-term cultivation on a soft polyacrylamide gel substrate in the presence of a cytokine complex and to determine the advantages of this method of maintaining hematopoiesis for further use in transplantation. To realize this purpose, the following methods were used: the method of long-term cultivation in vitro on a hydrogel substrate, the method of colony formation in semi-liquid agar, cytological research methods, light and inverted microscopy, statistical research methods. Due to the use of the hydrogel substrate together with the cytokine complex, a high proliferative activity of hematopoietic cells is observed, which is reflected in their expansion during long-term cultivation (5 weeks), as well as of high colony-forming activity (521.5 ± 7.5.105 per explanted cells). Thus, the stiffness of the substrate must be taken into account for the expansion of stem cells and their immediate descendants. The presence of a soft substrate made of polyacrylamide gel along with a complex of cytokines ensures the expansion of hematopoietic cells due to the long- term support of hematopoiesis.

Improved Methods for Bulk Cultivation and Fixation of Loxodes Ciliates for Fluorescence Microscopy

Loxodes is one of the best ecologically characterized ciliate genera with numerous intriguing physiological abilities, including gravity-sensing organelles and nitrate respiration. However, these cells have been considered challenging to cultivate in bulk, and are poorly preserved by conventional fixatives used for fluorescence microscopy. Here we describe methods to grow and harvest Loxodes cells in bulk with liquid soil extract medium, as well as a new fixative called ZFAE (zinc sulfate, formaldehyde, acetic acid, ethanol) that can fix Loxodes cells more effectively than buffered formaldehyde or methanol. We show that ZFAE is compatible with immunofluorescence and the nuclear stain DAPI. Loxodes is thus now amenable to long-term maintenance, large-scale growth, and modern cell biology investigations of monoclonal strains in laboratory conditions.

Contributions of Andrée Tixier-Vidal (1923-2021) to modern cell biology.

This article illustrates the main stages of the scientific career of Dr Andrée Tixier-Vidal, a pioneer in cell biology research in France. She made important discoveries in the field of hormone secretion and neuronal morphogenesis. She played a key role in developing pituitary and neuronal cultures and using electron microscopy to study cellular structures. Her scientific influence continues to irradiate through her students and collaborators.

Lentiviral Transduction of Mammary Epithelial Cells.

Lentiviral vectors are the workhorses of modern cell biology. They can infect a wide variety of cells including non-dividing cells and stem cells. They integrate into the genome of infected cells leading to stable expression. It is easy to transduce 100% of the cells in a culture and possible to infect cells simultaneously with multiple vectors, greatly facilitating studies on malignant transformation. We present simple protocols to produce and titrate lentiviral vectors, infect mammary epithelial cells, and check for contamination with replication competent viruses.

Integration and Spatial Organization of Signaling by G Protein-Coupled Receptor Homo- and Heterodimers.

Information flow from a source to a receiver becomes informative when the recipient can process the signal into a meaningful form. Information exchange and interpretation is essential in biology and understanding how cells integrate signals from a variety of information-coding molecules into complex orchestrated responses is a major challenge for modern cell biology. In complex organisms, cell to cell communication occurs mostly through neurotransmitters and hormones, and receptors are responsible for signal recognition at the membrane level and information transduction inside the cell. The G protein-coupled receptors (GPCRs) are the largest family of membrane receptors, with nearly 800 genes coding for these proteins. The recognition that GPCRs may physically interact with each other has led to the hypothesis that their dimeric state can provide the framework for temporal coincidence in signaling pathways. Furthermore, the formation of GPCRs higher order oligomers provides the structural basis for organizing distinct cell compartments along the plasma membrane where confined increases in second messengers may be perceived and discriminated. Here, we summarize evidence that supports these conjectures, fostering new ideas about the physiological role played by receptor homo- and hetero-oligomerization in cell biology.

Follistatin-Like Proteins: Structure, Functions and Biomedical Importance.

Main forms of cellular signal transmission are known to be autocrine and paracrine signaling. Several cells secrete messengers called autocrine or paracrine agents that can bind the corresponding receptors on the surface of the cells themselves or their microenvironment. Follistatin and follistatin-like proteins can be called one of the most important bifunctional messengers capable of displaying both autocrine and paracrine activity. Whilst they are not as diverse as protein hormones or protein kinases, there are only five types of proteins. However, unlike protein kinases, there are no minor proteins among them; each follistatin-like protein performs an important physiological function. These proteins are involved in a variety of signaling pathways and biological processes, having the ability to bind to receptors such as DIP2A, TLR4, BMP and some others. The activation or experimentally induced knockout of the protein-coding genes often leads to fatal consequences for individual cells and the whole body as follistatin-like proteins indirectly regulate the cell cycle, tissue differentiation, metabolic pathways, and participate in the transmission chains of the pro-inflammatory intracellular signal. Abnormal course of these processes can cause the development of oncology or apoptosis, programmed cell death. There is still no comprehensive understanding of the spectrum of mechanisms of action of follistatin-like proteins, so the systematization and study of their cellular functions and regulation is an important direction of modern molecular and cell biology. Therefore, this review focuses on follistatin-related proteins that affect multiple targets and have direct or indirect effects on cellular signaling pathways, as well as to characterize the directions of their practical application in the field of biomedicine.

Advanced high dynamic range fluorescence microscopy with Poisson noise modeling and integrated edge-preserving denoising

In the last decades, fluorescence microscopy has evolved into a powerful tool for modern cell biology and immunology. However, while modern fluorescence microscopes allow to study processes at subcellular level, the informative content of the recorded images is frequently constrained by the limited dynamic range of the camera mounted to the optical system. In addition, the quality of acquired images is generally affected by the typically low-light conditions that lead to comparatively high levels of noise in the data. Addressing these issues, we introduce a variational method for high dynamic range (HDR) imaging in the context of fluorescence microscopy that explicitly accounts for the Poisson statistics of the unavoidable signal-dependent photon shot noise and complements HDR image reconstruction with edge-preserving denoising. Since the proposed model contains a weight function to confine the influence of under- and overexposed pixels on the result, we briefly discuss the choice of this function. We evaluate our approach by showing HDR results for real fluorescence microscopy exposure sequences acquired with the recently developed MACSimaTM System for fully automated cyclic immunofluorescence imaging. These results are obtained using a first-order primal-dual implementation. On top of this, we also provide the corresponding saddle-point and dual formulations of the problem.

Organelle homeostasis principles: How organelle quality control and inter-organelle crosstalk promote cell survival.

To survive, cells sense their surroundings and adapt to enable homeostasis. Studies dissecting this process reveal organizational principles, including quality-control pathways, changes to organelle shape, and inter-organelle communication, that facilitate metabolic or developmental remodeling. In this issue, several reviews discuss these organelle homeostasis principles and how they are altered in disease.

HIGHLIGHTS ACROSS MYOLOGY: O.14 Gene editing using CRISPR/CAS9 in an animal model of nemaline myopathy

Gene editing in cells has revolutionized the paradigm of modern cell biology. The ease of use of the CRISPR/Cas9 system for gene manipulation has led to rapid and wide adoption across many fields, including biological research, biotechnology and medicine. This technology allows gene modification by producing a specific double stranded cut in the DNA and the repair by homology-independent targeted insertion (HITI) of DNA. We used CRISPR/CAS9 to modify specific mutations in-vitro in a muscular disorder to show its potential use as a therapeutic tool. We used cells from patients diagnosed with Nemaline myopathy with homozygous loss of exon 55 in the NEB gene due to a founder mutation. In addition, we corrected the exon 55 deletion in myotube cells from an animal model of Nemaline Myopathy (NEB-55). Taking advantage of DNA repair mechanism, we use the HITI to reintroduce exon 55 and re-establish its expression at the RNA and protein level. This study provides another piece of evidence that CRISPR/CAS9 based genome editing is a viable therapeutic avenue that can be pursued for treatment of neuromuscular disorders.

Janus sword actions of chloroquine and hydroxychloroquine against COVID-19

Chloroquine (CQ) and its analogue hydroxychloroquine (HCQ) have been thrust into our everyday vernacular because some believe, based on very limited basic and clinical data, that they might be helpful in preventing and/or lessening the severity of the pandemic coronavirus disease 2019 (COVID-19). However, lacking is a temperance in enthusiasm for their possible use as well as sufficient perspective on their effects and side-effects. CQ and HCQ have well-known properties of being diprotic weak bases that preferentially accumulate in acidic organelles (endolysosomes and Golgi apparatus) and neutralize luminal pH of acidic organelles. These primary actions of CQ and HCQ are responsible for their anti-malarial effects; malaria parasites rely on acidic digestive vacuoles for survival. Similarly, de-acidification of endolysosomes and Golgi by CQ and HCQ may block severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) integration into host cells because SARS-CoV-2 may require an acidic environment for its entry and for its ability to bud and infect bystander cells. Further, de-acidification of endolysosomes and Golgi may underly the immunosuppressive effects of these two drugs. However, modern cell biology studies have shown clearly that de-acidification results in profound changes in the structure, function and cellular positioning of endolysosomes and Golgi, in signaling between these organelles and other subcellular organelles, and in fundamental cellular functions. Thus, studying the possible therapeutic effects of CQ and HCQ against COVID-19 must occur concurrent with studies of the extent to which these drugs affect organellar and cell biology. When comprehensively examined, a better understanding of the Janus sword actions of these and other drugs might yield better decisions and better outcomes.

Index to Titles and Authors/Editors of Books Reviewed

Previous articleNext article FreeIndex to Titles and Authors/Editors of Books ReviewedPDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinked InRedditEmailQR Code SectionsMoreEntries are by title and author/editor.Abundant Earth: Toward an Ecological Civilization, by E. Crist, 164Across the Bridge: Understanding the Origin of the Vertebrates, by H. Gee, 134Adaptive Oncogenesis: A New Understanding of How Cancer Evolves Inside Us, by J. DeGregori, 167After the Death of Nature: Carolyn Merchant and the Future of Human-Nature Relations, ed. by K. Worthy et al., 165Alfred Russel Wallace Companion, ed. by C. H. Smith et al., 130Allen B., Pelican, 139Anctil M., Luminous Creatures: The History and Science of Light Production in Living Organisms, 135Animal Locomotion, by A. A. Biewener and S. N. Patek, 2nd ed., 157Ape That Understood the Universe: How the Mind and Culture Evolve, by S. Stewart-Williams, 150Arcadi A. C., Wild Chimpanzees: Social Behavior of an Endangered Species, 140Australian Beetles: Archostemata, Myxophaga, Adephaga, Polyphaga (part), Vol. 2, ed. by A. Ślipiński and J. F. Lawrence, 136A. W. F. Edwards on Phylogenetic Inference, Fisher’s Theorem, and Race, by E. Sober, lead review of Phylogenetic Inference, Selection Theory, and History of Science: Selected Papers of A. W. F. Edwards with Commentaries, ed. by R. G. Winther, 125Basl J., The Death of the Ethic of Life, 132Bat’s End: The Christmas Island Pipistrelle and Extinction in Australia, by J. Woinarski, 164Bennett M. J., and T. S. Posteraro (eds.), Deleuze and Evolutionary Theory, 151Biewener A. A., and S. N. Patek, Animal Locomotion, 2nd ed., 157Biology of Urban Environments, by P. James, 145Boles D. B., Cognitive Evolution, 162Bond A. B., and J. Diamond, Thinking Like a Parrot: Perspectives from the Wild, 156Brains as Engines of Association: An Operating Principle for Nervous Systems, by D. Purves, 159Braverman I., Coral Whisperers: Scientists on the Brink, 146Buckley P. A., et al., Urban Ornithology: 150 Years of Birds in New York City, 139Burdon J. J., and A.-L. Laine, Evolutionary Dynamics of Plant-Pathogen Interactions, 143Burkhardt F., and J. A. Secord (eds.), The Correspondence of Charles Darwin, Vol. 27 (1879), 132Butterflies of the World, by A. Hoskins, 137Buzz, Sting, Bite: Why We Need Insects, by A. Sverdrup-Thygeson, transl. by L. Moffatt, 136Caldwell M. W., The Origin of Snakes: Morphology and the Fossil Record, 138Cánovas F. M. (ed.), Molecular Physiology and Biotechnology of Trees, 144Carballo J. L., and J. J. Bell (eds.), Climate Change, Ocean Acidification and Sponges: Impacts Across Multiple Levels of Organization, 167Chaw S.-M., and R. K. Jansen (eds.), Plastid Genome Evolution, 143Chikungunya and Zika Viruses: Global Emerging Health Threats, ed. by S. Higgs et al., 168Climate Change, Ocean Acidification and Sponges: Impacts Across Multiple Levels of Organization, ed. by J. L. Carballo and J. J. Bell, 167Cognitive Evolution, by D. B. Boles, 162Consciousness Instinct: Unraveling the Mystery of How the Brain Makes the Mind, by M. S. Gazzaniga, 161Coral Whisperers: Scientists on the Brink, by I. Braverman, 146Corlett R. T., The Ecology of Tropical East Asia, 3rd ed., 145Correspondence of Charles Darwin, Vol. 27 (1879), ed. by F. Burkhardt and J. A. Secord, 132Crist E., Abundant Earth: Toward an Ecological Civilization, 164Cuvier’s History of the Natural Sciences: Twenty Lessons from the First Half of the Eighteenth Century, ed. and annotated by T. W. Pietsch, transl. by F. Andriamialisoa, 131Death of the Ethic of Life, by J. Basl, 132DeGregori J., Adaptive Oncogenesis: A New Understanding of How Cancer Evolves Inside Us, 167Deleuze and Evolutionary Theory, ed. by M. J. Bennett and T. S. Posteraro, 151Dunn P. O., and A. P. Møller (eds.), Effects of Climate Change on Birds, 2nd ed., 167Earll B., Marine Conservation: People, Ideas and Action, 166Ecology of Tropical East Asia, by R. T. Corlett, 3rd ed., 145Editor’s Guide to Writing and Publishing Science, by M. Hochberg, 135Effects of Climate Change on Birds, ed. by P. O. Dunn and A. P. Møller, 2nd ed., 167Elephant, by E. Fuller, 140Evolution and Development of Fishes, ed. by Z. Johanson et al., 158Evolution and Selection of Quantitative Traits, by B. Walsh and M. Lynch, 152Evolutionary Causation: Biological and Philosophical Reflections, ed. by T. Uller and K. N. Laland, 150Evolutionary Dynamics of Plant-Pathogen Interactions, by J. J. Burdon and A.-L. Laine, 143Evolution of the Sensitive Soul: Learning and the Origins of Consciousness, by S. Ginsburg and E. Jablonka, 160Eyes To See: The Astonishing Variety of Vision in Nature, by M. Land, 157Fossi M. C., and C. Panti (eds.), Marine Mammal Ecotoxicology: Impacts of Multiple Stressors on Population Health, 166Frank B., et al. (eds.), Human-Wildlife Interactions: Turning Conflict into Coexistence, 166Fuller E., Elephant, 140Gazzaniga M. S., The Consciousness Instinct: Unraveling the Mystery of How the Brain Makes the Mind, 161Gee H., Across the Bridge: Understanding the Origin of the Vertebrates, 134Ginsburg S., and E. Jablonka, The Evolution of the Sensitive Soul: Learning and the Origins of Consciousness, 160Goldfish, by A. M. Roos, 138Good Reasons for Bad Feelings: Insights from the Frontier of Evolutionary Psychiatry, by R. M. Nesse, 146Guide to the Plants of Arizona’s White Mountains, by G. C. West, 144Higgs S., et al. (eds.), Chikungunya and Zika Viruses: Global Emerging Health Threats, 168Hochberg M., An Editor’s Guide to Writing and Publishing Science, 135Hoskins A., Butterflies of the World, 137Human Genome in Health and Disease: A Story of Four Letters, by T. Samuelsson, 155Humanimal: How Homo sapiens Became Nature’s Most Paradoxical Creature: A New Evolutionary History, by A. Rutherford, 148Human Instinct: How We Evolved to Have Reason, Consciousness, and Free Will, by K. R. Miller, 147Human-Wildlife Interactions: Turning Conflict into Coexistence, ed. by B. Frank et al., 166Jacquemoud S., and S. Ustin, Leaf Optical Properties, 142James P., The Biology of Urban Environments, 145Johanson Z., et al. (eds.), Evolution and Development of Fishes, 158Kauffman S. A., A World Beyond Physics: The Emergence and Evolution of Life, 133Kingfisher, by I. Szabo, 138Land M., Eyes To See: The Astonishing Variety of Vision in Nature, 157Lannoo M. J., This Land Is Your Land: The Story of Field Biology in America, 145Leaf Optical Properties, by S. Jacquemoud and S. Ustin, 142Life Histories, Vol. 5, ed. by G. A. Wellborn and M. Thiel, 135Life in Deep Time: Darwin’s “Missing” Fossil Record, by J. W. Schopf, 153Lostroh P., Molecular and Cellular Biology of Viruses, 162Luminous Creatures: The History and Science of Light Production in Living Organisms, by M. Anctil, 135Mammalogy Techniques Lab Manual, by J. M. Ryan, 141Marine Conservation: People, Ideas and Action, by B. Earll, 166Marine Mammal Ecotoxicology: Impacts of Multiple Stressors on Population Health, ed. by M. C. Fossi and C. Panti, 166Miller K. R., The Human Instinct: How We Evolved to Have Reason, Consciousness, and Free Will, 147Molecular and Cellular Biology of Viruses, by P. Lostroh, 162Molecular Physiology and Biotechnology of Trees, ed. by F. M. Cánovas, 144Morrison M. L., et al. (eds.), Ornithology: Foundation, Analysis, and Application, 138Nature’s Giants: The Biology and Evolution of the World’s Largest Lifeforms, by G. D. Ruxton, 141Nesse R. M., Good Reasons for Bad Feelings: Insights from the Frontier of Evolutionary Psychiatry, 146Nowak K., et al. (eds.), Primates in Flooded Habitats: Ecology and Conservation, 144Origin of Snakes: Morphology and the Fossil Record, by M. W. Caldwell, 138Ornithology: Foundation, Analysis, and Application, ed. by M. L. Morrison et al., 138Pelican, by B. Allen, 139Phylogenetic Inference, Selection Theory, and History of Science: Selected Papers of A. W. F. Edwards with Commentaries, ed. by R. G. Winther, 125Pietsch T. W. (ed. and annotated), Cuvier’s History of the Natural Sciences: Twenty Lessons from the First Half of the Eighteenth Century, transl. by F. Andriamialisoa, 131Plastid Genome Evolution, ed. by S.-M. Chaw and R. K. Jansen, 143Primates in Flooded Habitats: Ecology and Conservation, ed. by K. Nowak et al., 144Prothero D. R., The Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them, 154Purves D., Brains as Engines of Association: An Operating Principle for Nervous Systems, 159Quammen D., The Tangled Tree: A Radical New History of Life, 152Reynolds A. S., The Third Lens: Metaphor and the Creation of Modern Cell Biology, 163Roos A. M., Goldfish, 138Rutherford A., Humanimal: How Homo sapiens Became Nature’s Most Paradoxical Creature: A New Evolutionary History, 148Ruxton G. D., Nature’s Giants: The Biology and Evolution of the World’s Largest Lifeforms, 141Ryan J. M., Mammalogy Techniques Lab Manual, 141Samuelsson T., The Human Genome in Health and Disease: A Story of Four Letters, 155Schopf J. W., Life in Deep Time: Darwin’s “Missing” Fossil Record, 153Searle J. B., et al. (eds.), Shrews, Chromosomes and Speciation, 139Shrews, Chromosomes and Speciation, ed. by J. B. Searle et al., 139Ślipiński A., and J. F. Lawrence (eds.), Australian Beetles: Archostemata, Myxophaga, Adephaga, Polyphaga (part), Vol. 2, 136Smith C. H., et al. (eds.), An Alfred Russel Wallace Companion, 130Sober E., A. W. F. Edwards on Phylogenetic Inference, Fisher’s Theorem, and Race, lead review of Phylogenetic Inference, Selection Theory, and History of Science: Selected Papers of A. W. F. Edwards with Commentaries, ed. by R. G. Winther, 125Stewart-Williams S., The Ape That Understood the Universe: How the Mind and Culture Evolve, 150Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them, by D. R. Prothero, 154Sverdrup-Thygeson A., Buzz, Sting, Bite: Why We Need Insects, transl. by L. Moffatt, 136Szabo I., Kingfisher, 138Tangled Tree: A Radical New History of Life, by D. Quammen, 152Terrace H. S., Why Chimpanzees Can’t Learn Language and Only Humans Can, 155Thinking Like a Parrot: Perspectives from the Wild, by A. B. Bond and J. Diamond, 156Third Lens: Metaphor and the Creation of Modern Cell Biology, by A. S. Reynolds, 163This Land Is Your Land: The Story of Field Biology in America, by M. J. Lannoo, 145Uller T., and K. N. Laland (eds.), Evolutionary Causation: Biological and Philosophical Reflections, 150Urban Ornithology: 150 Years of Birds in New York City, by P. A. Buckley et al., 139Walsh B., and M. Lynch, Evolution and Selection of Quantitative Traits, 152Wellborn G. A., and M. Thiel (eds.), Life Histories, Vol. 5, 135West G. C., Guide to the Plants of Arizona’s White Mountains, 144Why Chimpanzees Can’t Learn Language and Only Humans Can, by H. S. Terrace, 155Wild Chimpanzees: Social Behavior of an Endangered Species, by A. C. Arcadi, 140Winther R. G. (ed.), Phylogenetic Inference, Selection Theory, and History of Science: Selected Papers of A. W. F. Edwards with Commentaries, 125Woinarski J., A Bat’s End: The Christmas Island Pipistrelle and Extinction in Australia, 164World Beyond Physics: The Emergence and Evolution of Life, by S. A. Kauffman, 133Worthy K., et al. (eds.), After the Death of Nature: Carolyn Merchant and the Future of Human-Nature Relations, 165 Previous articleNext article DetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 95, Number 2June 2020 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/709123 Copyright © 2020 by The University of Chicago Press. All rights reserved.PDF download Crossref reports no articles citing this article.

The Eighth Day of Creation: looking back across 40 years to the birth of molecular biology and the roots of modern cell biology.

Forty years ago, Horace Judson’s The Eighth Day of Creation was published, a book vividly recounting the foundations of modern biology, the molecular biology revolution. This book inspired many in my generation. The anniversary provides a chance for a new generation to take a look back, to see how science has and hasn’t changed. Many central players in the book, including Sydney Brenner, Seymour Benzer, and François Jacob, would go on to be among the founders of modern cell biology, developmental biology, and neurobiology. These players come alive via their own words, as complex individuals, both heroes and anti-heroes. The technologies and experimental approaches they pioneered, ranging from cell fractionation to immunoprecipitation to structural biology, and the multidisciplinary approaches they took continue to power and inspire our work today. In the process, Judson brings out of the shadows the central roles played by women in many of the era’s discoveries. He provides us with a vision of how science and scientists have changed, of how many things about our endeavor never change, and of how some new ideas are perhaps not as new as we would like to think.

Data mining for traffic information.

Modern cell biology is now rich with data acquired at the whole genome and proteome level. We can add value to this data through integration and application of specialist knowledge. To illustrate, we will focus on the SNARE and RAB proteins; key regulators of intracellular fusion specificity and organelle identity. We examine published mass spectrometry data to gain an estimate of protein copy number and organelle distribution in HeLa cells for each family member. We also survey recent global CRISPR/Cas9 screens for essential genes from these families. We highlight instances of co-essentiality with other genes across a large panel of cell lines that allows for the identification of functionally coherent clusters. Examples of such correlations include RAB10 with the SNARE protein Syntaxin4 (STX4) and RAB7/RAB21 with the WASH and the CCC (COMMD/CCDC22/CCDC93) complexes, both of which are linked to endosomal recycling pathways.

Boronic acid-rich dendrimer for efficient intracellular peptide delivery

Interests in intracellular peptide delivery have continued to grow, significantly fueled by the importance of peptides and their mimetics in modern cell biology and pharmaceutical industry. However, efficient intracellular delivery of membrane-impermeable peptides of different polarities remains a challenging task. In this study, we develop a general and robust strategy for intracellular peptide delivery by using a boronic acid-rich dendrimer. The designed material is capable of transporting peptides with different polarities and charge properties into the cytosol of various cell lines without inducing additional cytotoxicity. The transduction efficacy and proteolytic stability of cargo peptides delivered by the boronic acid-rich dendrimer are much superior to peptides conjugated with cell penetrant peptides such as octaarginine. In addition, the bioactivities of pro-apoptotic peptides are maintained after intracellular delivery. This study provides a versatile and robust platform for the intracellular delivery of membrane-impermeable peptides.

The diffusive injection micropipette (DIMP)

The microinjection of fluorescent probes into live cells is an essential component in the toolbox of modern cell biology. Microinjection techniques include the penetration of the plasma membrane and, if present, the cell wall with micropipettes, and the application of pressure or electrical currents to drive the micropipette contents into the cell. These procedures interfere with cellular functions and therefore may induce artifacts. We designed the diffusive injection micropipette (DIMP) that avoids most of the possible artifacts due to the drastically reduced volume of its fluid contents and the utilization of diffusion for cargo delivery into the target cell. DIMPs were successfully tested in plant, fungal, and animal cells. Using the continuity of cytoplasmic dynamics over ten minutes after impalement of Nicotiana trichome cells as a criterion for non-invasiveness, we found DIMPs significantly less disruptive than conventional pressure microinjection. The design of DIMPs abolishes major sources of artifacts that cannot be avoided by other microinjection techniques. Moreover, DIMPs are inexpensive, easy to produce, and can be applied without specific equipment other than a micromanipulator. With these features, DIMPs may become the tool of choice for studies that require the least invasive delivery possible of materials into live cells.

The Mechanism of Fear at Behavior, Brain Circuits and Molecular Level

The study of “fear” can be traced back to the differences between “behaviorism” and “psychoanalysis” on cognition, while recent research on the learning and memory of fear by using modern cell and molecular biology experimental techniques has made our understanding of “fear” gradually multi-level and in-depth. At present, our research on fear can be divided into three levels, namely behavior, brain circuits and molecular. At the level of behavior, Pavlovian conditioning experiments have become the core method for studying fear, and behavioral approaches have been used for fear-related mental illnesses, such as the treatment of Post-Traumatic Stress Disorder (PTSD). At the level of brain circuits, the brain circuits with the amygdala as the core have gradually become clear, and there is also a two-system or one-system debate on how to recognize the fear process. At the molecular level, the Hebbian synaptic plasticity mechanism and neuromodulatory-dependent mechanism are used to explain the process of fear memory acquisition. Based on the current three levels of research, revealing how feelings of fear may generate is likely to play a guiding role in the further understanding of “fear” and treatment of related diseases.

E. E. Just's broad, yet hidden, influence on modern cell and developmental biology.

This year, 2019, marks the centennial of embryologist E. E. Just's discovery of what is known as the fast block to polyspermy. Just's observation of the subtle changes that occur at the egg's surface during fertilization (and in experimental parthenogenesis) led him to postulate that the egg, and indeed every cell, possesses a property he called independent irritability, which represents the cell's ability to respond in a physiologically-relevant way to a variety of signals or triggers. In this paper, I argue that Just's concept of independent irritability informed his contemporary Johannes Holtfreter as Holtfreter attempted to explain the phenomena of embryonic induction and competence and that Holtfreter, in turn, influenced Marc Kirschner and John Gerhart in their formulation of the theory of facilitated variation. Just's influence is especially evident in Gerhart and Kirschner's presentations of what they call weak linkage-a property of living systems that allows core processes and components to be mixed and matched in different ways to generate novel traits. Unfortunately, the connection between Holtfreter's work and Just's has remained hidden. This paper gives examples of phenomena that exhibit weak linkage, and it lays out the case that Just's concept of independent irritability, through Holtfreter, Gerhart, and Kirschner, has broadly infiltrated modern cell and developmental biology.

Advances in Cryopreservation of Bull Sperm.

Cryopreservation of semen and artificial insemination have an important, positive impact on cattle production, and product quality. Through the use of cryopreserved semen and artificial insemination, sperm from the best breeding bulls can be used to inseminate thousands of cows around the world. Although cryopreservation of bull sperm has advanced beyond that of other species, there are still major gaps in the knowledge and technology bases. Post-thaw viability of sperm is still low and differs significantly among the breeding bulls. These weaknesses are important because they are preventing advances both in fundamental science of mammalian gametes and reproductive biotechnology. Various extenders have been developed and supplemented with chemicals to reduce cryodamage or oxidative stress with varying levels of success. More detailed insights on sperm morphology and function have been uncovered through application of advanced tools in modern molecular and cell biology. This article provides a concise review of progress in the cryopreservation of bull sperm, advances in extender development, and frontiers using diverse techniques of the study of sperm viability. This scientific resource is important in animal biotechnology because with the advances in discovery of sperm fertility markers, there is an urgent need to improve post-thaw viability and fertility of sperm through enhanced cryopreservation for precision agriculture to produce food animals to ensure food security on the global scale.