scholarly journals Studies on the Growth of Tissues In Vitro

1937 ◽  
Vol 14 (3) ◽  
pp. 255-266
Author(s):  
F. JACOBY ◽  
O. A. TROWELL ◽  
E. N. WILLMER
Keyword(s):  
Cell Division ◽  
Latent Period ◽  
Effective Dose ◽  
Appreciable Amount ◽  
Minimum Effective Dose ◽  
Tyrode Solution ◽  
Daughter Cells ◽  
Duration Of Mitosis ◽  
Division Process

1. Embryo juice initiates in cells growing in plasma alone a process which after a latent period of some 10-12 hours culminates in cell division, and it is not necessary for the embryo juice to be present in any appreciable amount during the actual division process. 2. The approximate minimum effective dose is 5 per cent embryo juice in Tyrode solution acting for 3 hours. 15 and 40 per cent juice produce marked effects when applied for only 1 hour. 3. The concentration of embryo juice is a more important factor in determining the number of mitoses produced than is the time for which it acts. 4. Unless the embryo juice remain in contact with the culture for more than 10 hours, only one crop of mitoses occurs; but if it is present in the medium during or after the occurrence of the first divisions, then a second crop of divisions takes place. Evidence is adduced that it is the daughter cells produced during the first crop of mitoses which divide to produce the second crop. 5. The duration of mitosis is correlated with the concentration of the embryo juice. It approaches a minimum of about 40 min. 6. The duration of mitosis, particularly that of the ana- and telophases, is correlated with the rate of migration of the cells. 7. When a second crop of mitoses occurs in these cultures which have passed through a period in plasma alone, there is evidence that the size of the cells in metaphase of mitosis is significantly less than that of the cells of the first crop.

scholarly journals Studies on the Growth of Tissues in vitro

1936 ◽  
Vol 13 (2) ◽  
pp. 237-248
Author(s):  
E. N. WILLMER ◽  
F. JACOBY
Keyword(s):  
Cell Division ◽  
Latent Period ◽  
Tyrode Solution ◽  
Cell Degeneration ◽  
Fluid Medium ◽  
Embryo Extract ◽  
Low Concentrations ◽  
Growth Promoting ◽  
Migration Of Cells

1. A method is described for testing the growth-promoting properties of various substances on tissues in vitro. 2. When growth of cells (chick fibroblasts) has ceased in a medium of plasma and Tyrode solution, it may be restarted again by the addition of embryo extract. 3. There is a latent period of from 2 to 3 hours before a greatly increased migration of cells occurs. 4. There is a latent period of from 10 to 12 hours before cell division starts again. After that time the percentage of cells dividing increases for the next 12 hours and then declines. 5. For low concentrations of extract the growth is proportional to the concentration. 6. Cell division of neither heart fibroblasts nor of periosteal fibroblasts is inhibited by concentrations of extract higher than 15 per cent in Tyrode solution, but cultures of periosteal fibroblasts in such concentrations cause a "liquefaction" of the plasma medium. With heart fibroblasts, "liquefaction" of the medium does not readily occur, within the duration of these experiments, until the concentration of extract reaches 60 per cent. 7. The growth of two cultures in embryo extract, and embryo extract and serum respectively, has been followed for 10 consecutive days. The rate of cell division in the medium containing serum was less rapid. Cell degeneration commenced in both cultures after about 6 days, so that after about 8 or 10 days there was no further increase in the number of cells on the field. The addition of fresh fluid medium to the cultures was clearly reflected in corresponding increases in the values of the mitotic indices.

Structural requirements for stimulation by thyrotropin-releasing hormone of α-MSH release from rainbow trout (Oncorhynchus mykiss) pituitary fragments in vitro

1994 ◽  
Vol 72 (11) ◽  
pp. 1872-1879 ◽  
Author(s):  
R. Steven Schwartzentruber ◽  
Hubert Vaudry ◽  
Robert J. Omeljaniuk
Keyword(s):  
Biological Activity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Effective Dose ◽  
Dose Response ◽  
Histidine Residue ◽  
Minimum Effective Dose ◽  
Structural Requirements ◽  
Rainbow Trout Oncorhynchus Mykiss

Juvenile rainbow trout (Oncorhynchus mykiss) pituitary glands were isolated and the neurointermediate lobes (NILs) were removed from the partes distalis. NILs were surgically fragmented, pooled, and superfused in vitro with culture media, then treated with 3-min pulses of native thyrotropin-releasing hormone (TRH) or TRH analog; 10-min fractions were collected and stored (−20 °C) for subsequent analysis of α-melanocyte-stimulating hormone (α-MSH) content by specific radioimmunoassay. After 1–2 h of superfusion, α-MSH release from the NIL remained relatively constant; α-MSH-like immunoreactivity was not detected in eluate from the partes distalis in a series of parallel experiments. Native TRH stimulated acute releases of α-MSH from the NILs with a minimum effective dose of 10−9 M and an estimated ED50 of 1.73 × 10−9 M on the basis of increasing dose–response experiments; decreasing dose–response data provide an estimated minimum effective dose and ED50 of 10−9 and 1.57 × 10−9 M, respectively. No up- or down-regulatory effect was observed when NIL fragments were treated with repeated large (10−6 M) doses of TRH. By comparison, increasing pulse concentrations of pGlu-3-Me-His-Pro-NH2 (MeTRH) stimulated α-MSH release with a minimum effective dose of 10−10 M and an estimated ED50 of 1.56 × 10−9 M. Substitution of the histidine residue with phenylalanine decreased the stimulatory actions of TRH so that the minimum effective dose was 10−6 M. Substitution at either the amino terminus ([Glu1]TRH and [1-Me-(S)-dihydroorotyl1]TRH) or carboxy terminus (pGlu-His and TRH-Gly) resulted in near complete loss of bioactivity. To the best of our knowledge, this is the first investigation of the structural requirements for TRH biological activity in the teleost pituitary. Our data indicate that the structural criteria for TRH stimulation of α-MSH from the teleost pituitary are highly conservative; modification of TRH beyond the methylation of the histidine residue results in massive loss of biological activity. These data are consistent with our previous demonstrations of highly conservative structural requirements for TRH-receptor recognition in the trout pituitary and hypothalamus.

scholarly journals Coordinated regulation of the ESCRT-III component CHMP4C by the chromosomal passenger complex and centralspindlin during cytokinesis

Open Biology ◽  
2016 ◽  
Vol 6 (10) ◽  
pp. 160248 ◽  
Author(s):  
Luisa Capalbo ◽  
Ioanna Mela ◽  
Maria Alba Abad ◽  
A. Arockia Jeyaprakash ◽  
J. Michael Edwardson ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Cell Division ◽  
Aurora B ◽  
Aurora B Kinase ◽  
Chromosomal Passenger Complex ◽  
Force Microscopy ◽  
Daughter Cells ◽  
Atomic Force ◽  
Chromosomal Passenger

The chromosomal passenger complex (CPC)—composed of Aurora B kinase, Borealin, Survivin and INCENP—surveys the fidelity of genome segregation throughout cell division. The CPC has been proposed to prevent polyploidy by controlling the final separation (known as abscission) of the two daughter cells via regulation of the ESCRT-III CHMP4C component. The molecular details are, however, still unclear. Using atomic force microscopy, we show that CHMP4C binds to and remodels membranes in vitro . Borealin prevents the association of CHMP4C with membranes, whereas Aurora B interferes with CHMP4C's membrane remodelling activity. Moreover, we show that CHMP4C phosphorylation is not required for its assembly into spiral filaments at the abscission site and that two distinctly localized pools of phosphorylated CHMP4C exist during cytokinesis. We also characterized the CHMP4C interactome in telophase cells and show that the centralspindlin complex associates preferentially with unphosphorylated CHMP4C in cytokinesis. Our findings indicate that gradual dephosphorylation of CHMP4C triggers a ‘relay’ mechanism between the CPC and centralspindlin that regulates the timely distribution and activation of CHMP4C for the execution of abscission.

Effects of high hydrostatic pressure on bacterial cytoskeleton FtsZ polymers in vivo and in vitro

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1965-1972 ◽  
Author(s):  
Akihiro Ishii ◽  
Takako Sato ◽  
Masaaki Wachi ◽  
Kazuo Nagai ◽  
Chiaki Kato
Keyword(s):  
Cell Division ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Elevated Pressure ◽  
Immunofluorescent Staining ◽  
E Coli ◽  
Division Process ◽  
Indirect Immunofluorescent

Some rod-shaped bacteria, including Escherichia coli, exhibit cell filamentation without septum formation under high-hydrostatic-pressure conditions, indicating that the cell-division process is affected by hydrostatic pressure. The effects of elevated pressure on FtsZ-ring formation in E. coli cells were examined using indirect immunofluorescence microscopy. Elevated pressure of 40 MPa completely inhibited colony formation of E. coli cells under the cultivation conditions used, and the cells exhibited obviously filamentous shapes. In the elongated cells, normal cell-division processes appeared to be inhibited, because no FtsZ rings were observed by indirect immunofluorescent staining. In addition, it was observed that hydrostatic pressure dissociated the E. coli FtsZ polymers in vitro. These results suggest that high hydrostatic pressure directly affects cell survival and morphology through the dissociation of the cytoskeletal frameworks.

scholarly journals The bacterial DNA binding protein MatP involved in linking the nucleoid terminal domain to the divisome at midcell interacts with lipid membranes

2018 ◽  
Author(s):  
Begoña Monterroso ◽  
Silvia Zorrilla ◽  
Marta Sobrinos-Sanguino ◽  
Miguel Ángel Robles-Ramos ◽  
Carlos Alfonso ◽  
...  
Keyword(s):  
Cell Division ◽  
Dna Binding ◽  
Dna Sequences ◽  
Lipid Membranes ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
E Coli ◽  
Daughter Cells ◽  
Z Ring

ABSTRACTDivision ring formation at midcell is controlled by various mechanisms inEscherichia coli, one of them being the linkage between the chromosomal Ter macrodomain and the Z-ring mediated by MatP, a DNA binding protein that organizes this macrodomain and contributes to the prevention of premature chromosome segregation. Here we show that, during cell division, just before splitting the daughter cells, MatP seems to localize close to the cytoplasmic membrane, suggesting that this protein might interact with lipids. To test this hypothesis, we investigated MatP interaction with lipidsin vitro. We found that MatP, when encapsulated inside microdroplets generated by microfluidics and giant vesicles, accumulates at phospholipid bilayers and monolayers matching the lipid composition in theE. coliinner membrane. MatP binding to lipids was independently confirmed using lipid coated microbeads and bio-layer interferometry assays. Interaction of MatP with the lipid membranes also occurs in the presence of the DNA sequences specifically targeted by the protein but there is no evidence of ternary membrane/protein/DNA complexes. We propose that the interaction of MatP with lipids may modulate its spatiotemporal localization and its recognition of other ligands.IMPORTANCEThe division of anE. colicell into two daughter cells with equal genomic information and similar size requires duplication and segregation of the chromosome and subsequent scission of the envelope by a protein ring, the Z-ring. MatP is a DNA binding protein that contributes both to the positioning of the Z-ring at midcell and the temporal control of nucleoid segregation. Our integratedin vivoandin vitroanalysis provides evidence that MatP can interact with lipid membranes comprising the phospholipid mixture in theE. coliinner membrane, without concomitant recruitment of the short DNA sequences specifically targeted by MatP. This observation strongly suggests that the membrane may play a role in the regulation of the function and localization of MatP, which could be relevant for the coordination of the two fundamental processes in which this protein participates, nucleoid segregation and cell division.

Chemical Composition and Antimicrobial Activity of Essential Oil and Hydrosol Extract From Roots of Plumbago europaea and In-vitro Combinatory Antimicrobial Effect of Hydrosol extract with Gentamicin and Amphotericin B

2020 ◽  
Vol 10 ◽  
Author(s):  
Faiza Kaddour ◽  
Nadia Aissaoui ◽  
Mohammed El Amine Dib ◽  
Okkacha Bensaid ◽  
Alain Muselli
Keyword(s):  
Chemical Composition ◽  
Side Effects ◽  
Essential Oil ◽  
Effective Dose ◽  
Amphotericin B ◽  
Bacterial Resistance ◽  
Antimicrobial Effect ◽  
Antimicrobial Activities ◽  
Minimum Effective Dose

Background: Infectious diseases are responsible worldwide for millions of deaths a year. Antibiotics, which have saved so many lives and improved life expectancy, may become ineffective due to a worrying increase in bacterial resistance. Some of the appropriate actions that could be initiated to address this problem are to develop and search for new antimicrobial substances from medicinal plants, and combine antibiotics with antimicrobials agents isolated from a reservoir of bioactive natural product. Objectives: The purpose of this work was to study the chemical composition of the essential oil and hydrosol extract of Plumbago europaea, to evaluate their in-vitro antimicrobial activities and evaluate in-vitro combinatory antimicrobial effect of hydrosol extract with Gentamicin and Amphotericin B against a large panel of microorganisms in an effort to reduce their minimum effective dose and minimizing their side effects. Methods: The essential oil and hydrosol extract obtained from roots of Plumbago europaea were analyzed by GC/MS and tested for their antibacterial and antifungal activities against twelve different strains of microorganisms. The effectiveness, in-vitro, of the association between the hydrosol extract and both Gentamicin and Amphotericin B was also investigated using the checkerboard method. Results: The obtained results revealed that nine and four components, representing for 92.4 % and 97.4% of the total essential oil and hydrosol extract composition were identified, respectively and hydrosol extract was more active than the essential oil against all screened microorganisms, with interesting MIC values (19 μg/mL). An important effect of hydrosol extract was obtained in decreasing the MIC of Gentamicin and Amphotericin B in all tested combinations. Conclusion: The in-vitro combination of the hydrosol extract with Gentamicin and Amphotericin B led to substantial MIC reduction against all tested microorganisms. This combination can help to reduce the minimum effective dose of antimicrobial drugs used, which may help to decrease their side effects; and deliver these medicines with similar potency.

scholarly journals MATURATION OF HEMOLYSIN-PRODUCING CELL CLONES

1969 ◽  
Vol 130 (3) ◽  
pp. 543-556 ◽  
Author(s):  
George C. Saunders
Keyword(s):  
Cell Division ◽  
Latent Period ◽  
Induction Period ◽  
Generation Time ◽  
Sheep Erythrocyte ◽  
Precursor Cells ◽  
Cell Clones ◽  
Synchronous Cell ◽  
Erythrocyte Antigen

Investigations of the induction period of an in vitro hemolysin response to sheep erythrocyte antigen revealed the following: 1. After antigen stimulation precursors of plaque-forming cells rapidly maturate to the point of hemolysin production. 2. Initial maturation probably occurs in the absence of cell division. 3. After initial maturation, a latent period of about 12 hr occurs before the first doubling of PFC. 4. At least the first three cell doublings are synchronous, with a generation time of 7–8 hr. 5. Synchronous cell division implies that all precursor cells are at the same point in the cell cyde when they are initially stimulated.

scholarly journals Sid2p, a Spindle Pole Body Kinase That Regulates the Onset of Cytokinesis

1999 ◽  
Vol 146 (4) ◽  
pp. 777-790 ◽  
Author(s):  
Cynthia A. Sparks ◽  
Mary Morphew ◽  
Dannel McCollum
Keyword(s):  
Cell Division ◽  
Kinase Activity ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Vitro Assay ◽  
Daughter Cells ◽  
Division Site ◽  
Pole Body ◽  
Ring Constriction

The fission yeast Schizosaccharomyces pombe divides by medial fission through the use of an actomyosin contractile ring. Precisely at the end of anaphase, the ring begins to constrict and the septum forms. Proper coordination of cell division with mitosis is crucial to ensure proper segregation of chromosomes to daughter cells. The Sid2p kinase is one of several proteins that function as part of a novel signaling pathway required for initiation of medial ring constriction and septation. Here, we show that Sid2p is a component of the spindle pole body at all stages of the cell cycle and localizes transiently to the cell division site during medial ring constriction and septation. A medial ring and an intact microtubule cytoskeleton are required for the localization of Sid2p to the division site. We have established an in vitro assay for measuring Sid2p kinase activity, and found that Sid2p kinase activity peaks during medial ring constriction and septation. Both Sid2p localization to the division site and activity depend on the function of all of the other septation initiation genes: cdc7, cdc11, cdc14, sid1, spg1, and sid4. Thus, Sid2p, a component of the spindle pole body, by virtue of its transient localization to the division site, appears to determine the timing of ring constriction and septum delivery in response to activating signals from other Sid gene products.

scholarly journals FtsZ Interactions and Biomolecular Condensates as Potential Targets for New Antibiotics

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 254
Author(s):  
Silvia Zorrilla ◽  
Begoña Monterroso ◽  
Miguel-Ángel Robles-Ramos ◽  
William Margolin ◽  
Germán Rivas
Keyword(s):  
Cell Division ◽  
Bacterial Resistance ◽  
Protein Ligand Interactions ◽  
Protein Partners ◽  
Central Protein ◽  
Ligand Interactions ◽  
New Antibiotics ◽  
Division Process

FtsZ is an essential and central protein for cell division in most bacteria. Because of its ability to organize into dynamic polymers at the cell membrane and recruit other protein partners to form a “divisome”, FtsZ is a leading target in the quest for new antibacterial compounds. Strategies to potentially arrest the essential and tightly regulated cell division process include perturbing FtsZ’s ability to interact with itself and other divisome proteins. Here, we discuss the available methodologies to screen for and characterize those interactions. In addition to assays that measure protein-ligand interactions in solution, we also discuss the use of minimal membrane systems and cell-like compartments to better approximate the native bacterial cell environment and hence provide a more accurate assessment of a candidate compound’s potential in vivo effect. We particularly focus on ways to measure and inhibit under-explored interactions between FtsZ and partner proteins. Finally, we discuss recent evidence that FtsZ forms biomolecular condensates in vitro, and the potential implications of these assemblies in bacterial resistance to antibiotic treatment.

scholarly journals ZapE Is a Novel Cell Division Protein Interacting with FtsZ and Modulating the Z-Ring Dynamics

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Benoit S. Marteyn ◽  
Gouzel Karimova ◽  
Andrew K. Fenton ◽  
Anastasia D. Gazi ◽  
Nicholas West ◽  
...  
Keyword(s):  
Cell Division ◽  
Bacterial Cell ◽  
Dependent Manner ◽  
Bacterial Cell Division ◽  
Low Oxygen ◽  
Ftsz Ring ◽  
Division Process ◽  
Z Ring ◽  
Cell Division Protein

ABSTRACTBacterial cell division requires the formation of a mature divisome complex positioned at the midcell. The localization of the divisome complex is determined by the correct positioning, assembly, and constriction of the FtsZ ring (Z-ring). Z-ring constriction control remains poorly understood and (to some extent) controversial, probably due to the fact that this phenomenon is transient and controlled by numerous factors. Here, we characterize ZapE, a novel ATPase found in Gram-negative bacteria, which is required for growth under conditions of low oxygen, while loss ofzapEresults in temperature-dependent elongation of cell shape. We found that ZapE is recruited to the Z-ring during late stages of the cell division process and correlates with constriction of the Z-ring. Overexpression or inactivation ofzapEleads to elongation ofEscherichia coliand affects the dynamics of the Z-ring during division.In vitro, ZapE destabilizes FtsZ polymers in an ATP-dependent manner.IMPORTANCEBacterial cell division has mainly been characterizedin vitro. In this report, we could identify ZapE as a novel cell division protein which is not essentialin vitrobut is required during an infectious process. The bacterial cell division process relies on the assembly, positioning, and constriction of FtsZ ring (the so-called Z-ring). Among nonessential cell division proteins recently identified, ZapE is the first in which detection at the Z-ring correlates with its constriction. We demonstrate that ZapE abundance has to be tightly regulated to allow cell division to occur; absence or overexpression of ZapE leads to bacterial filamentation. AszapEis not essential, we speculate that additional Z-ring destabilizing proteins transiently recruited during late cell division process might be identified in the future.

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