Influence of physical factors on the growth of insect cells in vitro

In Vitro ◽  
1974 ◽  
Vol 10 (3-4) ◽  
pp. 149-156 ◽  
Author(s):  
T. J. Kurtti ◽  
Surendra P. S. Chaudhary ◽  
Marion A. Brooks
Keyword(s):  
Insect Cells ◽  
Physical Factors

Influence of physical factors on the growth of insect cells in vitro

In Vitro ◽  
1975 ◽  
Vol 11 (5) ◽  
pp. 274-285 ◽  
Author(s):  
T. J. Kurtti ◽  
Surendra P. S. Chaudhary ◽  
Marion A. Brooks
Keyword(s):  
Insect Cells ◽  
Physical Factors

scholarly journals Ovaries of Chrysanthemum Irradiated with High-Energy Photons and High-Energy Electrons Can Regenerate Plants with Novel Traits

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1111
Author(s):  
Natalia Miler ◽  
Iwona Jedrzejczyk ◽  
Seweryn Jakubowski ◽  
Janusz Winiecki
Keyword(s):  
Total Dose ◽  
In Vitro Regeneration ◽  
High Energy ◽  
Mutation Breeding ◽  
Chrysanthemum Morifolium ◽  
Physical Factors ◽  
Strong Impact ◽  
Breeding Method ◽  
High Energy Electrons

Classical mutation breeding using physical factors is a common breeding method for ornamental crops. The aim of our study was to examine the utility of ovaries excised from irradiated inflorescences of Chrysanthemum × morifolium (Ramat.) as explants for breeding purposes. We studied the in vitro regeneration capacity of the ovaries of two chrysanthemum cultivars: ‘Profesor Jerzy’ and ‘Karolina’ preceded by irradiation with high-energy photons (total dose 5, 10 and 15 Gy) and high-energy electrons (total dose 10 Gy). Growth and inflorescence parameters of greenhouse acclimatized regenerants were recorded, and ploidy level was estimated with flow cytometry. The strong impact of genotype on regeneration efficiency was recorded—cultivar ‘Karolina’ produced only 7 viable shoots, while ‘Profesor Jerzy’ produced totally 428 shoots. With an increase of irradiation dose, the regeneration decreased, the least responsive were explants irradiated with 15 Gy high-energy photons and 10 Gy high-energy electrons. Regenerants of ‘Profesor Jerzy’ obtained from these explants possessed shorter stem and flowered later. The highest number of stable, color and shape inflorescence variations were obtained from explants treated with 10 Gy high-energy photons. Variations of inflorescences were predominantly changes of shape—from full to semi-full. New color phenotypes were dark yellow, light yellow and pinkish, among them only the dark yellow phenotype remained stable during second year cultivation. None of the regenerants were haploid. The application of ovaries irradiated within the whole inflorescence of chrysanthemum can be successfully applied in the breeding programs, provided the mother cultivar regenerate in vitro efficiently.

Intracellular calcium levels in the Plasmodium berghei ookinete

Parasitology ◽  
2008 ◽  
Vol 135 (12) ◽  
pp. 1355-1362 ◽  
Author(s):  
I. SIDÉN-KIAMOS ◽  
C. LOUIS
Keyword(s):  
Intracellular Calcium ◽  
Plasmodium Berghei ◽  
Calcium Concentration ◽  
Insect Cells ◽  
Ionophore A23187 ◽  
Rodent Malaria Parasite ◽  
Calcium Indicators ◽  
Intracellular Ca

SUMMARYOokinetes are the motile and invasive stages of Plasmodium parasites in the mosquito host. Here we explore the role of intracellular Ca2+ in ookinete survival and motility as well as in the formation of oocysts in vitro in the rodent malaria parasite Plasmodium berghei. Treatment with the Ca2+ ionophore A23187 induced death of the parasite, an effect that could be prevented if the ookinetes were co-incubated with insect cells before incubation with the ionophore. Treatment with the intracellular calcium chelator BAPTA/AM resulted in increased formation of oocysts in vitro. Calcium imaging in the ookinete using fluorescent calcium indicators revealed that the purified ookinetes have an intracellular calcium concentration in the range of 100 nm. Intracellular calcium levels decreased substantially when the ookinetes were incubated with insect cells and their motility was concomitantly increased. Our results suggest a pleiotropic role for intracellular calcium in the ookinete.

Effect of chemical and physical factors in in vitro propagation and volatile fraction analysis ofAloysia triphylla(L’Herit) Britton

2017 ◽  
pp. 309-316
Author(s):  
G.M. Silva ◽  
J.P. Alvarenga ◽  
S.K.V. Bertolucci ◽  
M.C. Tavares ◽  
M.A. Rodrigues ◽  
...  
Keyword(s):  
In Vitro Propagation ◽  
Volatile Fraction ◽  
Physical Factors

scholarly journals Proteolytic processing of Semliki Forest virus-specific non-structural polyprotein by nsP2 protease

2001 ◽  
Vol 82 (4) ◽  
pp. 765-773 ◽  
Author(s):  
Andres Merits ◽  
Lidia Vasiljeva ◽  
Tero Ahola ◽  
Leevi Kääriäinen ◽  
Petri Auvinen
Keyword(s):  
Mammalian Cells ◽  
Active Sites ◽  
Insect Cells ◽  
Semliki Forest Virus ◽  
Point Mutations ◽  
Proteolytic Processing ◽  
Wild Type ◽  
In Trans ◽  
Polyprotein Precursor

The RNA replicase proteins of Semliki Forest virus (SFV) are translated as a P1234 polyprotein precursor that contains two putative autoproteases. Point mutations introduced into the predicted active sites of both proteases nsP2 (P2) and nsP4 (P4), separately or in combination, completely abolished virus replication in mammalian cells. The effects of these mutations on polyprotein processing were studied by in vitro translation and by expression of wild-type polyproteins P1234, P123, P23, P34 and their mutated counterparts in insect cells using recombinant baculoviruses. A mutation in the catalytic site of the P2 protease, C478A, (P2CA) completely abolished the processing of P12CA34, P12CA3 and P2CA3. Co-expression of P23 and P12CA34 in insect cells resulted in in trans cleavages at the P2/3 and P3/4 sites. Co-expression of P23 and P34 resulted in cleavage at the P3/4 site. In contrast, a construct with a mutation in the active site of the putative P4 protease, D6A, (P1234DA) was processed like the wild-type protein. P34 or its truncated forms were not processed when expressed alone. In insect cells, P4 was rapidly destroyed unless an inhibitor of proteosomal degradation was used. It is concluded that P2 is the only protease needed for the processing of SFV polyprotein P1234. Analysis of the cleavage products revealed that P23 or P2 could not cleave the P1/2 site in trans.

scholarly journals Role of mechanical cues and hypoxia on the growth of tumor cells in strong and weak confinement: A dual in vitro–in silico approach

2020 ◽  
Vol 6 (13) ◽  
pp. eaaz7130 ◽  
Author(s):  
V. Le Maout ◽  
K. Alessandri ◽  
B. Gurchenkov ◽  
H. Bertin ◽  
P. Nassoy ◽  
...  
Keyword(s):  
In Silico ◽  
Time Course ◽  
Growth Dynamics ◽  
Tumor Model ◽  
Mechanistic Modeling ◽  
Physical Factors ◽  
Factors Affecting ◽  
Numerical Studies

Characterization of tumor growth dynamics is of major importance for cancer understanding. By contrast with phenomenological approaches, mechanistic modeling can facilitate disclosing underlying tumor mechanisms and lead to identification of physical factors affecting proliferation and invasive behavior. Current mathematical models are often formulated at the tissue or organ scale with the scope of a direct clinical usefulness. Consequently, these approaches remain empirical and do not allow gaining insight into the tumor properties at the scale of small cell aggregates. Here, experimental and numerical studies of the dynamics of tumor aggregates are performed to propose a physics-based mathematical model as a general framework to investigate tumor microenvironment. The quantitative data extracted from the cellular capsule technology microfluidic experiments allow a thorough quantitative comparison with in silico experiments. This dual approach demonstrates the relative impact of oxygen and external mechanical forces during the time course of tumor model progression.

scholarly journals Regulation and Directing Stem Cell Fate by Tissue Engineering Functional Microenvironments: Scaffold Physical and Chemical Cues

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Fei Xing ◽  
Lang Li ◽  
Changchun Zhou ◽  
Cheng Long ◽  
Lina Wu ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Stem Cell ◽  
Growth Factors ◽  
Cell Fate ◽  
Chemical Cues ◽  
Physical Factors ◽  
Stem Cell Fate ◽  
Physical And Chemical

It is well known that stem cells reside within tissue engineering functional microenvironments that physically localize them and direct their stem cell fate. Recent efforts in the development of more complex and engineered scaffold technologies, together with new understanding of stem cell behavior in vitro, have provided a new impetus to study regulation and directing stem cell fate. A variety of tissue engineering technologies have been developed to regulate the fate of stem cells. Traditional methods to change the fate of stem cells are adding growth factors or some signaling pathways. In recent years, many studies have revealed that the geometrical microenvironment played an essential role in regulating the fate of stem cells, and the physical factors of scaffolds including mechanical properties, pore sizes, porosity, surface stiffness, three-dimensional structures, and mechanical stimulation may affect the fate of stem cells. Chemical factors such as cell-adhesive ligands and exogenous growth factors would also regulate the fate of stem cells. Understanding how these physical and chemical cues affect the fate of stem cells is essential for building more complex and controlled scaffolds for directing stem cell fate.

scholarly journals Roles of Disulfide Linkage and Calcium Ion-Mediated Interactions in Assembly and Disassembly of Virus-Like Particles Composed of Simian Virus 40 VP1 Capsid Protein

2001 ◽  
Vol 75 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Ken-Ichiro Ishizu ◽  
Hajime Watanabe ◽  
Song-Iee Han ◽  
Shin-Nosuke Kanesashi ◽  
Mainul Hoque ◽  
...  
Keyword(s):  
Amino Acid ◽  
Calcium Ion ◽  
Insect Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Ion Binding ◽  
Amino Acid Substitutions ◽  
Disulfide Linkage ◽  
Calcium Ion Binding

ABSTRACT The simian virus 40 capsid is composed of 72 pentamers of VP1 protein. Although the capsid is known to dissociate to pentamers in vitro following simultaneous treatment with reducing and chelating agents, the functional roles of disulfide linkage and calcium ion-mediated interactions are not clear. To elucidate the roles of these interactions, we introduced amino acid substitutions in VP1 at cysteine residues and at residues involved in calcium binding. We expressed the mutant proteins in a baculovirus system and analyzed both their assembly into virus-like particles (VLPs) in insect cells and the disassembly of those VLPs in vitro. We found that disulfide linkages at both Cys-9 and Cys-104 conferred resistance to proteinase K digestion on VLPs, although neither linkage was essential for the formation of VLPs in insect cells. In particular, reduction of the disulfide linkage at Cys-9 was found to be critical for VLP dissociation to VP1 pentamers in the absence of calcium ions, indicating that disulfide linkage at Cys-9 prevents VLP dissociation, probably by increasing the stability of calcium ion binding. We found that amino acid substitutions at carboxy-terminal calcium ion binding sites (Glu-329, Glu-330, and Asp-345) resulted in the frequent formation of unusual tubular particles as well as VLPs in insect cells, indicating that these residues affect the accuracy of capsid assembly. In addition, unexpectedly, amino acid substitutions at any of the calcium ion binding sites tested, especially at Glu-157, resulted in increased stability of VLPs in the absence of calcium ions in vitro. These results suggest that appropriate affinities of calcium ion binding are responsible for both assembly and disassembly of the capsid.

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