The Ecology and Evolution of Model Microbial Mutualisms

Author(s):  
Jeremy M. Chacón ◽  
Sarah P. Hammarlund ◽  
Jonathan N.V. Martinson ◽  
Leno B. Smith ◽  
William R. Harcombe

Mutually beneficial interspecific interactions are abundant throughout the natural world, including between microbes. Mutualisms between microbes are critical for everything from human health to global nutrient cycling. Studying model microbial mutualisms in the laboratory enables highly controlled experiments for developing and testing evolutionary and ecological hypotheses. In this review, we begin by describing the tools available for studying model microbial mutualisms. We then outline recent insights that laboratory systems have shed on the evolutionary origins, evolutionary dynamics, and ecological features of microbial mutualism. We touch on gaps in our current understanding of microbial mutualisms, note connections to mutualism in nonmicrobial systems, and call attention to open questions ripe for future study. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 52 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Xueyi Xue ◽  
Jiang Wang ◽  
Diwakar Shukla ◽  
Lily S. Cheung ◽  
Li-Qing Chen

Sugar translocation between cells and between subcellular compartments in plants requires either plasmodesmata or a diverse array of sugar transporters. Interactions between plants and associated microorganisms also depend on sugar transporters. The sugars will eventually be exported transporter (SWEET) family is made up of conserved and essential transporters involved in many critical biological processes. The functional significance and small size of these proteins have motivated crystallographers to successfully capture several structures of SWEETs and their bacterial homologs in different conformations. These studies together with molecular dynamics simulations have provided unprecedented insights into sugar transport mechanisms in general and into substrate recognition of glucose and sucrose in particular. This review summarizes our current understanding of the SWEET family, from the atomic to the whole-plant level. We cover methods used for their characterization, theories about their evolutionary origins, biochemical properties, physiological functions, and regulation. We also include perspectives on the future work needed to translate basic research into higher crop yields. Expected final online publication date for the Annual Review of Plant Biology, Volume 73 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Barrett Anthony Klein

Every facet of human culture is in some way affected by our abundant, diverse insect neighbors. Our relationship with insects has been on display throughout the history of art, sometimes explicitly but frequently in inconspicuous ways. This is because artists can depict insects overtly, but they can also allude to insects conceptually or use insect products in a purely utilitarian manner. Insects themselves can serve as art media, and artists have explored or exploited insects for their products (silk, wax, honey, propolis, carmine, shellac, nest material), body parts (e.g., wings), and whole bodies (dead, alive, individually, or as collectives). This review surveys insects and their products used as media in the visual arts and considers the untapped potential for artistic exploration of media derived from insects. The history, value, and ethics of insect media art are relevant topics at a time when the natural world is at unprecedented risk. Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
Vol 90 (1) ◽  
Author(s):  
Tim Krischuns ◽  
Maria Lukarska ◽  
Nadia Naffakh ◽  
Stephen Cusack

Influenza virus RNA-dependent RNA polymerase (FluPol) transcribes the viral RNA genome in the infected cell nucleus. In the 1970s, researchers showed that viral transcription depends on host RNA polymerase II (RNAP II) activity and subsequently that FluPol snatches capped oligomers from nascent RNAP II transcripts to prime its own transcription. Exactly how this occurs remains elusive. Here, we review recent advances in the mechanistic understanding of FluPol transcription and early events in RNAP II transcription that are relevant to cap-snatching. We describe the known direct interactions between FluPol and the RNAP II C-terminal domain and summarize the transcription-related host factors that have been found to interact with FluPol. We also discuss open questions regarding how FluPol may be targeted to actively transcribing RNAP II and the exact context and timing of cap-snatching, which is presumed to occur after cap completion but before the cap is sequestered by the nuclear cap-binding complex. Expected final online publication date for the Annual Review of Biochemistry, Volume 90 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
Vol 55 (1) ◽  
Author(s):  
Thomas O. Auer ◽  
Michael P. Shahandeh ◽  
Richard Benton

Defining the mechanisms by which animals adapt to their ecological niche is an important problem bridging evolution, genetics, and neurobiology. We review the establishment of a powerful genetic model for comparative behavioral analysis and neuroecology, Drosophila sechellia. This island-endemic fly species is closely related to several cosmopolitan generalists, including Drosophila melanogaster, but has evolved extreme specialism, feeding and reproducing exclusively on the noni fruit of the tropical shrub Morinda citrifolia. We first describe the development and use of genetic approaches to facilitate genotype/phenotype associations in these drosophilids. Next, we survey the behavioral, physiological, and morphological adaptations of D. sechellia throughout its life cycle and outline our current understanding of the genetic and cellular basis of these traits. Finally, we discuss the principles this knowledge begins to establish in the context of host specialization, speciation, and the neurobiology of behavioral evolution and consider open questions and challenges in the field. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
Vol 72 (1) ◽  
Author(s):  
Rainer Hedrich ◽  
Kenji Fukushima

Charles Darwin recognized that carnivorous plants thrive in nutrient-poor soil by capturing animals. Although the concept of botanical carnivory has been known for nearly 150 years, its molecular mechanisms and evolutionary origins have not been well understood until recently. In the last decade, technical advances have fueled the genome and transcriptome sequencings of active and passive hunters, leading to a better understanding of the traits associated with the carnivorous syndrome, from trap leaf development and prey digestion to nutrient absorption, exemplified by the Venus flytrap ( Dionaea muscipula), pitcher plant ( Cephalotus follicularis), and bladderwort ( Utricularia gibba). The repurposing of defense-related genes is an important trend in the evolution of plant carnivory. In this review, using the Venus flytrap as a representative of the carnivorous plants, we summarize the molecular mechanisms underlying their ability to attract, trap, and digest prey and discuss the origins of plant carnivory in relation to their genomic evolution. Expected final online publication date for the Annual Review of Plant Biology, Volume 72 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
Vol 75 (1) ◽  
Author(s):  
James C. Taggart ◽  
Jean-Benoît Lalanne ◽  
Gene-Wei Li

Bacterial protein synthesis rates have evolved to maintain preferred stoichiometries at striking precision, from the components of protein complexes to constituents of entire pathways. Setting relative protein production rates to be well within a factor of two requires concerted tuning of transcription, RNA turnover, and translation, allowing many potential regulatory strategies to achieve the preferred output. The last decade has seen a greatly expanded capacity for precise interrogation of each step of the central dogma genome-wide. Here, we summarize how these technologies have shaped the current understanding of diverse bacterial regulatory architectures underpinning stoichiometric protein synthesis. We focus on the emerging expanded view of bacterial operons, which encode diverse primary and secondary mRNA structures for tuning protein stoichiometry. Emphasis is placed on how quantitative tuning is achieved. We discuss the challenges and open questions in the application of quantitative, genome-wide methodologies to the problem of precise protein production. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


Author(s):  
José Ruiz-Franco ◽  
Emanuela Zaccarelli

In this review, we discuss recent advances in the investigation of colloidal systems interacting via a combination of short-range attraction and long-range repulsion. The prototypical examples of this phenomenology are charged colloids with depletion interactions, but the results apply, to a large extent, also to suspensions of globular proteins, clays, and, in general, to systems with competing attractive (hydrophobic) and repulsive (polar) contributions. After a brief introduction to the problem, we focus on the three disordered states that characterize these systems: equilibrium cluster phase, equilibrium gel, and Wigner glass of clusters. We provide a comparison of their static and dynamic observables, mainly by means of numerical simulations. Next, we discuss the few available studies on their viscoelastic properties and on their response to an external shear. Finally, we provide a summary of the current findings and also raise the main open questions and challenges for the future in this topic. Expected final online publication date for the Annual Review of Condensed Matter Physics, Volume 12 is March 10, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


Author(s):  
Gabriel D. Orebi Gann ◽  
Kai Zuber ◽  
Daniel Bemmerer ◽  
Aldo Serenelli

In this article we review the current state of the field of solar neutrinos, including flavor oscillations, nonstandard effects, solar models, cross section measurements, and the broad experimental program thus motivated and enabled. We describe the historical discoveries that contributed to current knowledge, and define critical open questions to be addressed in the next decade. We discuss standard solar models, including uncertainties and problems related to the solar composition, and review experimental and model solar neutrino fluxes, including future prospects. We review the state of the art of the nuclear reaction data relevant for solar fusion in the proton–proton chain and carbon–nitrogen–oxygen cycle. Finally, we review the current and future experimental programs that can address outstanding questions in this field. Expected final online publication date for the Annual Review of Nuclear and Particle Science, Volume 71 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


Author(s):  
Victoria E. Deneke ◽  
Andrea Pauli

Fertilization is a multistep process that culminates in the fusion of sperm and egg, thus marking the beginning of a new organism in sexually reproducing species. Despite its importance for reproduction, the molecular mechanisms that regulate this singular event, particularly sperm–egg fusion, have remained mysterious for many decades. Here, we summarize our current molecular understanding of sperm–egg interaction, focusing mainly on mammalian fertilization. Given the fundamental importance of sperm–egg fusion yet the lack of knowledge of this process in vertebrates, we discuss hallmarks and emerging themes of cell fusion by drawing from well-studied examples such as viral entry, placenta formation, and muscle development. We conclude by identifying open questions and exciting avenues for future studies in gamete fusion. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
Vol 39 (1) ◽  
Author(s):  
Annelise G. Snyder ◽  
Andrew Oberst

Nearly all animal cells contain proteins evolved to trigger the destruction of the cell in which they reside. The activation of these proteins occurs via sequential programs, and much effort has been expended in delineating the molecular mechanisms underlying the resulting processes of programmed cell death (PCD). These efforts have led to the definition of apoptosis as a form of nonimmunogenic PCD that is required for normal development and tissue homeostasis, and of pyroptosis and necroptosis as forms of PCD initiated by pathogen infection that are associated with inflammation and immune activation. While this paradigm has served the field well, numerous recent studies have highlighted cross-talk between these programs, challenging the idea that apoptosis, pyroptosis, and necroptosis are linear pathways with defined immunological outputs. Here, we discuss the emerging idea of cell death as a signaling network, considering connections between cell death pathways both as we observe them now and in their evolutionary origins. We also discuss the engagement and subversion of cell death pathways by pathogens, as well as the key immunological outcomes of these processes. Expected final online publication date for the Annual Review of Immunology, Volume 39 is April 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


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