scholarly journals Increasing demand for plasma membrane contributes to the energetic cost of early zebrafish embryogenesis

2019 ◽  
Author(s):  
Jonathan Rodenfels ◽  
Pablo Sartori ◽  
Stefan Golfier ◽  
Kartikeya Nagendra ◽  
Karla Neugebauer ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Heat Dissipation ◽  
Isothermal Calorimetry ◽  
Significant Proportion ◽  
Total Cell ◽  
Energetic Cost ◽  
Cleavage Stage ◽  
Energetic Costs ◽  
Cell Stage

AbstractHow do early embryos apportion the resources stored in the sperm and egg? Recently, we established isothermal calorimetry (ITC) to measure heat dissipation by living zebrafish embryos and to estimate the energetics of specific developmental events. During the reductive cleavage divisions, the rate of heat dissipation increases from ∼60 nJ·s−1 at the 2-cell stage to ∼90 nJ·s−1 at the 1024-cell stage. Here we ask, which cellular process(es) drive these increasing energetic costs? We present evidence that the cost is due to the increase in the total surface area of all of the cells of the embryo. First, embryo volume stays constant during the cleavage stage, indicating that the increase is not due to growth. Second, the heat increase is blocked by nocodazole, which inhibits DNA replication, mitosis and cell division; this implicates some aspect of cell proliferation contributing to these costs. Third, the heat increase scales with total cell surface area rather than total cell number. Finally, the calculated costs of maintaining and assembling plasma membranes and associated proteins probably accounts for a significant proportion of the heat increase. Thus, the cell’s membrane is likely to contribute significantly to the total energy budget of the embryo.Highlight summary for TOCRodenfels et al. measure the energetic costs of early zebrafish development, using calorimetry. Embryonic heat dissipation increases, but, more slowly than the number of cells during early cleavage stage development. Instead, the heat dissipation scales with the energetic cost associated with maintaining and producing new plasma membrane.

scholarly journals Contribution of increasing plasma membrane to the energetic cost of early zebrafish embryogenesis

2020 ◽  
Vol 31 (7) ◽  
pp. 520-526 ◽  
Author(s):  
Jonathan Rodenfels ◽  
Pablo Sartori ◽  
Stefan Golfier ◽  
Kartikeya Nagendra ◽  
Karla M. Neugebauer ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Heat Dissipation ◽  
Early Embryogenesis ◽  
Energetic Cost ◽  
Energetic Costs ◽  
Zebrafish Embryogenesis

The energetic costs of development were measured during early embryogenesis in zebrafish using calorimetry. The heat dissipated by the embryo increased with time. The heat dissipation scaled with the increasing surface area of the plasma membrane, suggesting that the energetic costs are associated with maintaining and/or producing plasma membrane.

The blastomere pattern in echinoderms: cleavages one to four

Development ◽  
1977 ◽  
Vol 40 (1) ◽  
pp. 23-34
Author(s):  
John W. Prothero ◽  
Arnold Tamarin
Keyword(s):  
Longitudinal Study ◽  
Surface Area ◽  
Formal Model ◽  
Egg Volume ◽  
Cleavage Stage ◽  
Cell Stage ◽  
Subjective Impression ◽  
Position And Orientation ◽  
The Individual ◽  
Area And Volume

The results of a longitudinal study of the blastomere pattern in six embryos during the first four cleavages are reported. At each cleavage stage optical sections through an embryo, taken at vertical intervals of 5 or 10µm, were recorded on 35 mm film: digitization of the blastomere contours and computer analysis allow calculation of the center, radius, surface area and volume of each blastomere. The subjective impression of exquisite regularity seen in normal echinoderm blastulae acquires a quantitative dimension from the present study. For example, the individual angles formed by the various quartets of blastomeres depart from right angles by at most a few degrees. The egg volume was found to be conserved up to the fourth cleavage. At the 16-cell stage, unlike the earlier stages, the blastomere positions cannot be ascribed solely to the position and orientation of the respective cleavage planes. Finally, a few features of a formal model of these early cleavages are sketched.

scholarly journals Lysosome exocytosis is required for mitosis

2018 ◽  
Author(s):  
Charlotte Nugues ◽  
Nordine Helassa ◽  
Dayani Rajamanoharan ◽  
Robert D Burgoyne ◽  
Lee P Haynes
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Membrane Trafficking ◽  
Regulatory Mechanism ◽  
Significant Proportion ◽  
Genetic Material ◽  
Adherent Cells ◽  
Membrane Material ◽  
Daughter Cells ◽  
Phosphatidylinositol 4

AbstractMitosis, the accurate segregation of duplicated genetic material into what will become two new daughter cells, is accompanied by extensive membrane remodelling and membrane trafficking activities. Early in mitosis, adherent cells partially detach from the substratum, round up and their surface area decreases. This likely results from an endocytic uptake of plasma membrane material. As cells enter cytokinesis they re-adhere, flatten and exhibit an associated increase in surface area. The identity of the membrane donor for this phase of mitosis remains unclear. Here we show by biochemical and imaging approaches that lysosomes undergo exocytosis at telophase and that this requires the activity of phosphatidylinositol 4-kinase-IIIβ. Inhibition of lysosome exocytosis resulted in mitotic failure in a significant proportion of cells suggesting that this facet of lysosome physiology is essential and represents a new regulatory mechanism in mitosis.

A novel H+ permeability dominating intracellular pH in the early mouse embryo

Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1353-1361
Author(s):  
J.M. Baltz ◽  
J.D. Biggers ◽  
C. Lechene
Keyword(s):  
Plasma Membrane ◽  
Intracellular Ph ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Types ◽  
Preimplantation Embryos ◽  
Developmentally Regulated ◽  
Cell Stage ◽  
K Concentration ◽  
Early Mouse

Most cell types are relatively impermeant to H+ and are able to regulate their intracellular pH by means of plasma membrane proteins, which transport H+ or bicarbonate across the membrane in response to perturbations of intracellular pH. Mouse preimplantation embryos at the 2-cell stage, however, do not appear to possess specific pH-regulatory mechanisms for relieving acidosis. They are, instead, highly permeable to H+, so that the intracellular pH in the acid and neutral range is determined by the electrochemical equilibrium of H+ across the plasma membrane. When intracellular pH is perturbed, the rate of the ensuing H+ flux across the plasma membrane is determined by the H+ electrochemical gradient: its dependence on external K+ concentration indicates probable dependence on membrane potential and the rate depends on the H+ concentration gradient across the membrane. The large permeability at the 2-cell stage is absent or greatly diminished in the trophectoderm of blastocysts, but still present in the inner cell mass. Thus, the permeability to H+ appears to be developmentally regulated.

Desmosomes in hamster cheek pouch epithelium: their quantitative characterization during epithelial differentiation

1984 ◽  
Vol 66 (1) ◽  
pp. 411-429
Author(s):  
F.H. White ◽  
K. Gohari
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Cheek Pouch ◽  
Unit Surface Area ◽  
Granular Cells ◽  
Hamster Cheek Pouch ◽  
Average Cell ◽  
Membrane Area ◽  
The Mean ◽  
Granular Layers

Desmosomes in stratified squamous epithelia appear to exhibit quantitative alterations during differentiation. In this work we use stereological and other morphometric methods to quantify these structures in epithelial cells from defined basal, spinous and granular strata. Hamster cheek pouch mucosa from five animals was processed for electron microscopy using strictly standardized techniques and a stratified random sampling procedure was used to obtain micrographs of cells from basal, spinous and granular layers. Stereological intersection counting techniques were used to determine for each layer the relative surface area of plasma membrane occupied by desmosomes (Ss), the number of desmosomes per unit surface area of plasma membrane (Ns), the mean individual desmosomal diameter (delta) and the mean individual desmosomal surface area (s). In addition, estimates of nuclear volume were obtained by direct measurement of nuclear profiles and volume-to-surface ratios were obtained by a combination of point and intersection counting, which enabled estimates for the volume (Vcell) and plasma membrane surface area (SPM) of the ‘average’ cell within each stratum to be acquired. Using this information, it was then possible to calculate both the total surface area (S) and the number (N) of desmosomes on the plasma membranes of average cells. The parameters Ss and Ns showed progressive increases between basal and granular layers, whereas values for delta and s were lower in granular cells when compared with basal and spinous cells. The parameters Vcell, SPM, S and N all increased progressively and significantly during differentiation. Between basal and granular layers, the mean cell volume and surface area had each increased approximately threefold, whereas the surface area and number of desmosomes on the average cell plasma membrane had increased approximately seven- and eleven-fold, respectively. Granular cells thus possess more numerous desmosomes, which occupy a greater proportion of the plasma membrane area but which are individually smaller, when compared with basal and spinous layers.

Incorporation of Uridine in Cleavage Stage Eggs of the Sea Urchin Paracentrotus Lividus

1971 ◽  
Vol 26 (8) ◽  
pp. 816-821 ◽  
Author(s):  
Larry E. Bockstahler
Keyword(s):  
Ion Exchange ◽  
Sea Urchin ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Paracentrotus Lividus ◽  
Cleavage Stage ◽  
Early Cleavage ◽  
Cell Stage ◽  
Cleavage Stages ◽  
Layer Chromatography

Incorporation of uridine in cleavage stage eggs of the sea urchin Paracentrotus lividus was investigated. It was shown by ion exchange and thin layer chromatography that most of the uridine taken up during the 16-cell stage was converted into UTP with some incorporation into UDP and UMP. Conversion of uridine to these phosphorylated nucleosides occurred throughout early cleavage stages. A very small amount of uridine taken up by cleavage stage eggs is incorporated into RNA heterogeneous in size. This RNA was examined by polyacrylamide gel electrophoresis.

scholarly journals AGS3-dependent trans-Golgi network membrane trafficking is essential for compaction in mouse embryos

2020 ◽  
Vol 133 (23) ◽  
pp. jcs243238
Author(s):  
Zheng-Wen Nie ◽  
Ying-Jie Niu ◽  
Wenjun Zhou ◽  
Dong-Jie Zhou ◽  
Ju-Yeon Kim ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Trafficking ◽  
Fluorescent Protein ◽  
Mouse Embryos ◽  
Cell Contact ◽  
Protein Signaling ◽  
Cell Stage ◽  
Trans Golgi Network ◽  
Early Mouse ◽  
Golgi Network

ABSTRACTActivator of G-protein signaling 3 (AGS3, also known as GPSM1) regulates the trans-Golgi network. The AGS3 GoLoco motif binds to Gαi and thereby regulates the transport of proteins to the plasma membrane. Compaction of early embryos is based on the accumulation of E-cadherin (Cdh1) at cell-contacted membranes. However, how AGS3 regulates the transport of Cdh1 to the plasma membrane remains undetermined. To investigate this, AGS3 was knocked out using the Cas9-sgRNA system. Both trans-Golgi network protein 46 (TGN46, also known as TGOLN2) and transmembrane p24-trafficking protein 7 (TMED7) were tracked in early mouse embryos by tagging these proteins with a fluorescent protein label. We observed that the majority of the AGS3-edited embryos were developmentally arrested and were fragmented after the four-cell stage, exhibiting decreased accumulation of Cdh1 at the membrane. The trans-Golgi network and TMED7-positive vesicles were also dispersed and were not polarized near the membrane. Additionally, increased Gαi1 (encoded by GNAI1) expression could rescue AGS3-overexpressed embryos. In conclusion, AGS3 reinforces the dynamics of the trans-Golgi network and the transport of TMED7-positive cargo containing Cdh1 to the cell-contact surface during early mouse embryo development.

scholarly journals Peptide-Based Formulation from Lactic Acid Bacteria Impairs the Pathogen Growth in Ananas Comosus (Pineapple)

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 457 ◽  
Author(s):  
Gabriela N. Tenea ◽  
Daniela Olmedo ◽  
Clara Ortega
Keyword(s):  
Significant Proportion ◽  
High Capacity ◽  
Total Cell ◽  
Ananas Comosus ◽  
Street Vending ◽  
E Coli ◽  
Cell Counts ◽  
Total Cell Density

Worldwide, street vending commerce has grown exponentially, representing in some countries, including Ecuador, a significant proportion of food consumed by the urban population. Pineapple is one of the common fruits sold as ready-to-eat slices by ambulant vendors in the street or on public transport at risk of contamination by various microorganisms. Previously, we selected Lactobacillus plantarum UTNCys5-4 and Lactococcus lactis subsp. lactis Gt28 strains producing peptides with high capacity to inhibit pathogen growth in vitro. In this study, the effect of different edited formulations containing a mixture of Cys5-4/Gt28 peptides was evaluated in vitro and ex vitro against a pathogenic cocktail containing E. coli (2), Salmonella (2) and Shigella (1). The growth of bacterial cocktail co-inoculated with cell-free supernatant containing peptides (formulation T1) and precipitated peptides (formulation T6), in a ratio of Cys5-4/Gt28:1:1 (v/v), results in a decrease of total cell viability with 1.85 and 1.2 log CFU/mL orders of magnitude at 6 h of incubation. About the same decrease (1.9 log CFU/g) was observed when pineapple slices artificially inoculated with the pathogenic cocktail were coated with T1 formulation, indicating the capacity to diminish simultaneous pathogens in situ, thus demonstrating its great biological control and protection. However, the E. coli cell counts reduced by 2.08 log CFU/g while Salmonella and Shigella cell counts reduced by 1.43 and 1.91 log CFU/g, respectively, at 5 days of refrigeration. In the untreated pineapple slices, the total cell density was maintained during storage, suggesting the adaptation of the pathogens to the fruit matrix. The peptide-based formulation exerted a bacteriolytic mode of action inducing pathogenic cell death. The results indicate that coating pineapple slices with peptide-based formulation is a promising approach to protect them from further contamination by microbial spoilage as well as an alternative to increase the food safety.

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