scholarly journals Role of the σD-Dependent Autolysins in Bacillus subtilis Population Heterogeneity

2008 ◽  
Vol 191 (18) ◽  
pp. 5775-5784 ◽  
Author(s):  
Rui Chen ◽  
Sarah B. Guttenplan ◽  
Kris M. Blair ◽  
Daniel B. Kearns
Keyword(s):  
Bacillus Subtilis ◽  
Cell Separation ◽  
Cell Types ◽  
Population Heterogeneity ◽  
Gene Encoding ◽  
Swarming Motility ◽  
Morphological Heterogeneity ◽  
Distinct Cell ◽  
Flagellum Biosynthesis ◽  
Necessary And Sufficient

ABSTRACT Exponentially growing populations of Bacillus subtilis contain two morphologically and functionally distinct cell types: motile individuals and nonmotile multicellular chains. Motility differentiation arises because RNA polymerase and the alternative sigma factor σD activate expression of flagellin in a subpopulation of cells. Here we demonstrate that the peptidoglycan-remodeling autolysins under σD control, LytC, LytD, and LytF, are expressed in the same subpopulation of cells that complete flagellar synthesis. Morphological heterogeneity is explained by the expression of LytF that is necessary and sufficient for cell separation. Moreover, LytC is required for motility but not at the level of cell separation or flagellum biosynthesis. Rather, LytC appears to be important for flagellar function, and motility was restored to a LytC mutant by mutation of either lonA, encoding the LonA protease, or a gene encoding a previously unannotated swarming motility inhibitor, SmiA. We conclude that heterogeneous activation of σD-dependent gene expression is sufficient to explain both the morphological heterogeneity and functional heterogeneity present in vegetative B. subtilis populations.

scholarly journals The prevalence and origin of exoprotease-producing cells in the Bacillus subtilis biofilm

Microbiology ◽  
2014 ◽  
Vol 160 (1) ◽  
pp. 56-66 ◽  
Author(s):  
Victoria L. Marlow ◽  
Francesca R. Cianfanelli ◽  
Michael Porter ◽  
Lynne S. Cairns ◽  
J. Kim Dale ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Single Cell Analysis ◽  
Response Regulator ◽  
Cell Types ◽  
Cell Analysis ◽  
Swarming Motility ◽  
Specialized Cell ◽  
Differentiated Cells ◽  
First Time

Biofilm formation by the Gram-positive bacterium Bacillus subtilis is tightly controlled at the level of transcription. The biofilm contains specialized cell types that arise from controlled differentiation of the resident isogenic bacteria. DegU is a response regulator that controls several social behaviours exhibited by B. subtilis including swarming motility, biofilm formation and extracellular protease (exoprotease) production. Here, for the first time, we examine the prevalence and origin of exoprotease-producing cells within the biofilm. This was accomplished using single-cell analysis techniques including flow cytometry and fluorescence microscopy. We established that the number of exoprotease-producing cells increases as the biofilm matures. This is reflected by both an increase at the level of transcription and an increase in exoprotease activity over time. We go on to demonstrate that exoprotease-producing cells arise from more than one cell type, namely matrix-producing and non-matrix-producing cells. In toto these findings allow us to add exoprotease-producing cells to the list of specialized cell types that are derived during B. subtilis biofilm formation and furthermore the data highlight the plasticity in the origin of differentiated cells.

In-droplet cell separation based on bipolar dielectrophoretic response to facilitate cellular droplet assays

Lab on a Chip ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 3832-3841 ◽  
Author(s):  
Song-I Han ◽  
Can Huang ◽  
Arum Han
Keyword(s):  
Cell Separation ◽  
Cell Types ◽  
Free Cell ◽  
Label Free ◽  
Separation Technology ◽  
Cellular Assays ◽  
System P ◽  
Distinct Cell

Novel in-droplet label-free cell separation technology is presented in this paper by utilizing different dielectrophoretic responses of two distinct cell types, enabling broader ranges of cellular assays to be implemented in the droplet-based microfluidics system.

Reciprocal signaling between Drosophila epidermal muscle attachment cells and their corresponding muscles

Development ◽  
1997 ◽  
Vol 124 (13) ◽  
pp. 2615-2622 ◽  
Author(s):  
S. Becker ◽  
G. Pasca ◽  
D. Strumpf ◽  
L. Min ◽  
T. Volk
Keyword(s):  
Ectopic Expression ◽  
Cell Types ◽  
Target Cells ◽  
Cell Analysis ◽  
Muscle Attachment ◽  
Somatic Muscle ◽  
Signaling Mechanism ◽  
Developmental Program ◽  
Distinct Cell ◽  
Necessary And Sufficient

Directed intercellular interactions between distinct cell types underlie the basis for organogenesis during embryonic development. This paper focuses on the establishment of the final somatic muscle pattern in Drosophila, and on the possible cross-talk between the myotubes and the epidermal muscle attachment cells, occurring while both cell types undergo distinct developmental programs. Our findings suggest that the stripe gene is necessary and sufficient to initiate the developmental program of epidermal muscle attachment cells. In stripe mutant embryos, these cells do not differentiate correctly. Ectopic expression of Stripe in various epidermal cells transforms these cells into muscle-attachment cells expressing an array of epidermal muscle attachment cell-specific markers. Moreover, these ectopic epidermal muscle attachment cells are capable of attracting somatic myotubes from a limited distance, providing that the myotube has not yet been attached to or been influenced by a closer wild-type attachment cell. Analysis of the relationships between muscle binding and differentiation of the epidermal muscle attachment cell was performed in mutant embryos in which loss of muscles, or ectopic muscles were induced. This analysis indicated that, although the initial expression of epidermal muscle-attachment cell-specific genes including stripe and groovin is muscle independent, their continuous expression is maintained only in epidermal muscle attachment cells that are connected to muscles. These results suggest that the binding of a somatic muscle to an epidermal muscle attachment cell triggers a signal affecting gene expression in the attachment cell. Taken together, our results suggest the presence of a reciprocal signaling mechanism between the approaching muscles and the epidermal muscle attachment cells. First the epidermal muscle attachment cells signal the myotubes and induce myotube attraction and adhesion to their target cells. Following this binding, the muscle cells send a reciprocal signal to the epidermal muscle attachment cells inducing their terminal differentiation into tendon-like cells.

scholarly journals Single-Cell Microscopy Reveals That Levels of Cyclic di-GMP Vary amongBacillus subtilisSubpopulations

2019 ◽  
Vol 201 (16) ◽  
Author(s):  
Cordelia A. Weiss ◽  
Jakob A. Hoberg ◽  
Kuanqing Liu ◽  
Benjamin P. Tu ◽  
Wade C. Winkler
Keyword(s):  
Bacillus Subtilis ◽  
Single Cell ◽  
Relative Abundance ◽  
Biofilm Formation ◽  
Single Cells ◽  
Cell Types ◽  
Population Heterogeneity ◽  
Competent Cell ◽  
Gram Positive ◽  
Content Type

ABSTRACTThe synthesis of signaling molecules is one strategy bacteria employ to sense alterations in their environment and rapidly adjust to those changes. In Gram-negative bacteria, bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) regulates the transition from a unicellular motile state to a multicellular sessile state. However, c-di-GMP signaling has been less intensively studied in Gram-positive organisms. To that end, we constructed a fluorescentyfpreporter based on a c-di-GMP-responsive riboswitch to visualize the relative abundance of c-di-GMP for single cells of the Gram-positive model organismBacillus subtilis. Coupled with cell-type-specific fluorescent reporters, this riboswitch reporter revealed that c-di-GMP levels are markedly different amongB. subtiliscellular subpopulations. For example, cells that have made the decision to become matrix producers maintain higher intracellular c-di-GMP concentrations than motile cells. Similarly, we find that c-di-GMP levels differ between sporulating and competent cell types. These results suggest that biochemical measurements of c-di-GMP abundance are likely to be inaccurate for a bulk ensemble ofB. subtiliscells, as such measurements will average c-di-GMP levels across the population. Moreover, the significant variation in c-di-GMP levels between cell types hints that c-di-GMP might play an important role duringB. subtilisbiofilm formation. This study therefore emphasizes the importance of using single-cell approaches for analyzing metabolic trends within ensemble bacterial populations.IMPORTANCEMany bacteria have been shown to differentiate into genetically identical yet morphologically distinct cell types. Such population heterogeneity is especially prevalent among biofilms, where multicellular communities are primed for unexpected environmental conditions and can efficiently distribute metabolic responsibilities.Bacillus subtilisis a model system for studying population heterogeneity; however, a role for c-di-GMP in these processes has not been thoroughly investigated. Herein, we introduce a fluorescent reporter, based on a c-di-GMP-responsive riboswitch, to visualize the relative abundance of c-di-GMP for singleB. subtiliscells. Our analysis shows that c-di-GMP levels are conspicuously different amongB. subtiliscellular subtypes, suggesting a role for c-di-GMP during biofilm formation. These data highlight the utility of riboswitches as tools for imaging metabolic changes within individual bacterial cells. Analyses such as these offer new insight into c-di-GMP-regulated phenotypes, especially given that other biofilms also consist of multicellular communities.

GATA2 is required for the generation of V2 interneurons

Development ◽  
2000 ◽  
Vol 127 (17) ◽  
pp. 3829-3838 ◽  
Author(s):  
Y. Zhou ◽  
M. Yamamoto ◽  
J.D. Engel
Keyword(s):  
Spinal Cord ◽  
Cell Lineage ◽  
Cell Types ◽  
Neuronal Population ◽  
Neuronal Markers ◽  
Distinct Cell ◽  
Urogenital Development ◽  
Necessary And Sufficient ◽  
Insight Into ◽  
Ventral Spinal Cord

During embryogenesis, transcription factor GATA2 is expressed in a variety of distinct cell types, and earlier experiments showed that GATA2 is a vital regulator of both hematopoiesis and urogenital development. Despite the fact that GATA2 is expressed early and abundantly in the nervous system, there has been no demonstration of its direct participation in neurogenesis. We show here that GATA2 is expressed in the ventral spinal cord exclusively in newly generated V2 interneurons, suggesting that GATA2 might be required for the generation of this discrete neuronal population. Proof for this hypothesis was provided by showing that the number of cells expressing V2 neuronal markers was drastically diminished in gata2 null mutant embryos. The tissue-specific enhancer that directs gata2 transcription specifically in V2 neurons was localized to a 190 bp intragenic element lying within gata2 intron 5, and this element is both necessary and sufficient to confer GATA2 spinal cord expression. The identification of a V2-specific enhancer should allow fundamental new insight into the genetic hierarchy of regulatory events that govern neurogenesis in a well-defined cell lineage.

Fine Structure of the Malpighian Tubules of the Mosquito, Culex pipiens

1971 ◽  
Vol 29 ◽  
pp. 402-403
Author(s):  
Brendan Clifford
Keyword(s):  
Fine Structure ◽  
Culex Pipiens ◽  
Stellate Cell ◽  
Malpighian Tubule ◽  
Cell Types ◽  
Instar Larva ◽  
Malpighian Tubules ◽  
Calliphora Erythrocephala ◽  
Distinct Cell ◽  
Basal Plasma

An ultrastructural investigation of the Malpighian tubules of the fourth instar larva of Culex pipiens was undertaken as part of a continuing study of the fine structure of transport epithelia.Each of the five Malpighian tubules was found to be morphologically identical and regionally undifferentiated. Two distinct cell types, the primary and stellate, were found intermingled along the length of each tubule. The ultrastructure of the stellate cell was previously described in the Malpighian tubule of the blowfly, Calliphora erythrocephala by Berridge and Oschman.The basal plasma membrane of the primary cell is extremely irregular, giving rise to a complex interconnecting network of basal channels. The compartments of cytoplasm entrapped within this system of basal infoldings contain mitochondria, free ribosomes, and small amounts of rough endoplasmic reticulum. The mitochondria are distinctive in that the cristae run parallel to the long axis of the organelle.

scholarly journals NF-κB in Cancer Immunity: Friend or Foe?

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 355
Author(s):  
Guilhem Lalle ◽  
Julie Twardowski ◽  
Yenkel Grinberg-Bleyer
Keyword(s):  
Immune Responses ◽  
Therapeutic Potential ◽  
Cell Types ◽  
Transcriptional Activators ◽  
New Class ◽  
Complex Interactions ◽  
Cancer Immunity ◽  
Distinct Cell ◽  
Cancer Initiation ◽  
Cancer Outcome

The emergence of immunotherapies has definitely proven the tight relationship between malignant and immune cells, its impact on cancer outcome and its therapeutic potential. In this context, it is undoubtedly critical to decipher the transcriptional regulation of these complex interactions. Following early observations demonstrating the roles of NF-κB in cancer initiation and progression, a series of studies converge to establish NF-κB as a master regulator of immune responses to cancer. Importantly, NF-κB is a family of transcriptional activators and repressors that can act at different stages of cancer immunity. In this review, we provide an overview of the selective cell-intrinsic contributions of NF-κB to the distinct cell types that compose the tumor immune environment. We also propose a new view of NF-κB targeting drugs as a new class of immunotherapies for cancer.

scholarly journals Glucocorticoid Receptor β (GRβ): Beyond Its Dominant-Negative Function

2021 ◽  
Vol 22 (7) ◽  
pp. 3649
Author(s):  
Patricia Ramos-Ramírez ◽  
Omar Tliba
Keyword(s):  
Current Knowledge ◽  
Inflammatory Diseases ◽  
Cell Communication ◽  
Cell Types ◽  
The Body ◽  
Dominant Negative ◽  
Negative Effects ◽  
Independent Manner ◽  
Distinct Cell ◽  
Induced Apoptosis

Glucocorticoids (GCs) act via the GC receptor (GR), a receptor ubiquitously expressed in the body where it drives a broad spectrum of responses within distinct cell types and tissues, which vary in strength and specificity. The variability of GR-mediated cell responses is further extended by the existence of GR isoforms, such as GRα and GRβ, generated through alternative splicing mechanisms. While GRα is the classic receptor responsible for GC actions, GRβ has been implicated in the impairment of GRα-mediated activities. Interestingly, in contrast to the popular belief that GRβ actions are restricted to its dominant-negative effects on GRα-mediated responses, GRβ has been shown to have intrinsic activities and “directly” regulates a plethora of genes related to inflammatory process, cell communication, migration, and malignancy, each in a GRα-independent manner. Furthermore, GRβ has been associated with increased cell migration, growth, and reduced sensitivity to GC-induced apoptosis. We will summarize the current knowledge of GRβ-mediated responses, with a focus on the GRα-independent/intrinsic effects of GRβ and the associated non-canonical signaling pathways. Where appropriate, potential links to airway inflammatory diseases will be highlighted.

scholarly journals Development, characterization, and applications of multi-material stereolithography bioprinting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bagrat Grigoryan ◽  
Daniel W. Sazer ◽  
Amanda Avila ◽  
Jacob L. Albritton ◽  
Aparna Padhye ◽  
...  
Keyword(s):  
Material Selection ◽  
Cell Types ◽  
Fluorescent Tracers ◽  
Regional Feature ◽  
Multicellular Aggregates ◽  
Distinct Cell ◽  
Adenocarcinoma Cells ◽  
Mammalian Tissues ◽  
Heterotypic Interactions ◽  
Feature Alignment

AbstractAs a 3D bioprinting technique, hydrogel stereolithography has historically been limited in its ability to capture the spatial heterogeneity that permeates mammalian tissues and dictates structure–function relationships. This limitation stems directly from the difficulty of preventing unwanted material mixing when switching between different liquid bioinks. Accordingly, we present the development, characterization, and application of a multi-material stereolithography bioprinter that provides controlled material selection, yields precise regional feature alignment, and minimizes bioink mixing. Fluorescent tracers were first used to highlight the broad design freedoms afforded by this fabrication strategy, complemented by morphometric image analysis to validate architectural fidelity. To evaluate the bioactivity of printed gels, 344SQ lung adenocarcinoma cells were printed in a 3D core/shell architecture. These cells exhibited native phenotypic behavior as evidenced by apparent proliferation and formation of spherical multicellular aggregates. Cells were also printed as pre-formed multicellular aggregates, which appropriately developed invasive protrusions in response to hTGF-β1. Finally, we constructed a simplified model of intratumoral heterogeneity with two separate sub-populations of 344SQ cells, which together grew over 14 days to form a dense regional interface. Together, these studies highlight the potential of multi-material stereolithography to probe heterotypic interactions between distinct cell types in tissue-specific microenvironments.

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