scholarly journals Development of shoots of Hedyotis corymbosa (L) Lam in vitro culture

2015 ◽  
Vol 18 (4) ◽  
pp. 75-84
Author(s):  
Tuan Anh Le ◽  
Tham Thi Thu Hoang ◽  
Hoang Ngo Phan
Keyword(s):  
Light Intensity ◽  
Ursolic Acid ◽  
Oleanolic Acid ◽  
Sucrose Concentration ◽  
Shoot Formation ◽  
Culture Conditions ◽  
High Biological Activity ◽  
Medium Culture

Hedyotis corymbosa is one of weedy herb belonging to Rubiaceae family. It has been studied and used as a traditional medicine for the treatment of snakebite, antihepatotoxic and cancer. Notably, ursolic acid and oleanolic acid, compounds presented high biological activity in H. Corymbosa, were reported having anti-inflammatory, antibacterial, antioxidant and inhibited the growth of cancer cells. In the present study, fragments of stems containing an axillary bud are cultured on MS½ medium supplemented with 1 mg/L BA and 0.2 mg/L IAA is the best condition which gives the highest number of shoot formation. The shoots are come from the callus of cortex. In different culture conditions (increase the sucrose concentration in the medium culture, increase the light intensity, supplemented with 3 % PEG), shoots grow up strongly under 7,500 lx light intensity, especially in this culture condition the respiratory rate and the concentration of ursolic acid and oleanolic acid are the highest. The respiratory changes and the role of endogenous hormones in the shoot regeneration and the response of shoots in different culture conditions have been analyzed and discussed.

scholarly journals IMMUNE RESPONSES IN VITRO

1971 ◽  
Vol 134 (2) ◽  
pp. 395-416 ◽  
Author(s):  
Carl W. Pierce ◽  
Barbara M. Johnson ◽  
Harriet E. Gershon ◽  
Richard Asofsky
Keyword(s):  
Culture Conditions ◽  
Antibody Concentration ◽  
Spleen Cells ◽  
Immunoglobulin Class ◽  
Cell Densities ◽  
Erythrocyte Antigen ◽  
First Time ◽  
Kinetics Of

We have demonstrated for the first time that mouse spleen cells stimulated in vitro with heterologous erythrocytes developed immunoglobulin class-specific γM, γ1, γ2a+2b, and γA plaque-forming cell (PFC) responses. A modification of the hemolytic plaque technique, the addition of goat anti-mouse µ-chain antibody to the assay preparation, specifically prevented development of all γM PFC and enabled accurate and reproducible enumeration of immunoglobulin class-specific PFC after treatment with appropriate monospecific anti-globulins and complement. Culture conditions, with regard to medium, atmosphere, agitation, and spleen cell densities, were similar to those previously shown to support only γM PFC responses. Evaluation of the kinetics of appearance of PFC showed that γM PFC reached maximum numbers on days 4–5; the magnitude of this response was 3–10 times greater than γ1 γ2a+2b, or γA PFC which reached maximum numbers on days 5–6. Optimal erythrocyte antigen dose for γM PFC responses was 107/culture, whereas a dose of 106 erythrocytes/culture consistently stimulated optimal γ1 γ2a+2b, or γA PFC responses. Investigations of the effects of anti-erythrocyte antibody on γM and γG PFC responses indicated that antibody suppressed these responses by neutralizing the effective antigenic stimulus at the macrophage-dependent phase of the response. At the same antibody concentration, γG PFC responses were more effectively suppressed than γM PFC responses. Further, γG responses could be almost completely suppressed by antibody as long as 48 hr after initiation of cultures, whereas γM PFC responses could only be completely suppressed during the first 24 hr. These results were discusssed in terms of the role of antigen in the stimulation γM and γG antibody.

Fructose 2,6-bisphosphate biosynthesis and regulation of carbohydrate metabolism in Aspergillus oryzae

1998 ◽  
Vol 44 (1) ◽  
pp. 6-11
Author(s):  
Gandhi Rádis-Baptista ◽  
David N. Urquizo Valdivia ◽  
José Abrahão-Neto
Keyword(s):  
Cyclic Amp ◽  
Carbohydrate Metabolism ◽  
Aspergillus Oryzae ◽  
Culture Conditions ◽  
Dependent Protein Kinase ◽  
Fructose 1,6 Bisphosphatase ◽  
Dependent Protein ◽  
Regulation Of Carbohydrate Metabolism

The biosynthesis and role of fructose 2,6-bisphosphate (Fru-2,6-P2) in carbohydrate metabolism during induction of an amylolytic system in Aspergillus oryzae was studied. Fluctuations in Fru-2,6-P2 were not dependent on the external glucose concentration during induction, whereas the level of Fru-2,6-P2 increased significantly when the oxygen concentration was diminished. Phosphofructokinase II (PFK II) of A. oryzae was sensitive to phosphorylation in vitro by the catalytic subunit of cyclic AMP dependent protein kinase, which increased the Vmax (twofold), although the Km (0.7 mM) remained unchanged. Phosphofructokinase I was neither activated by micromolar Fru-2,6-P2 nor inhibited by high ATP concentrations. The activity of fructose-1,6-bisphosphatase (FBPase) was subject to strong inhibition by Fru-2,6-P2. Addition of glucose to cultures under gluconeogenic conditions caused a decrease of approximately 40% in the FBPase activity within 4 min. These results indicate that the effect of Fru-2,6-P2 in A. oryzae could preferentially control gluconeogenesis. The addition of 0.1 M glucose under gluconeogenic culture conditions also showed that Fru-2,6-P2 fluctuations appeared to be, at least in short term, more closely related to temporal changes in the hexose-6-phosphate concentration.Key words: Aspergillus oryzae; fructose-2,6-bisphosphate; phosphofructokinase II (PFK II); cyclic AMP; gluconeogenesis control.

scholarly journals Role of Hyperglycemia in the Senescence of Mesenchymal Stem Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Min Yin ◽  
Yan Zhang ◽  
Haibo Yu ◽  
Xia Li
Keyword(s):  
Diabetes Mellitus ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Culture Conditions ◽  
Cell Aging ◽  
Immunomodulatory Properties ◽  
Sound Foundation ◽  
Prevalence Of Diabetes Mellitus

The regenerative and immunomodulatory properties of mesenchymal stem cells (MSCs) have laid a sound foundation for their clinical application in various diseases. However, the clinical efficiency of MSC treatments varies depending on certain cell characteristics. Among these, the roles of cell aging or senescence cannot be excluded. Despite their stemness, evidence of senescence in MSCs has recently gained attention. Many factors may contribute to the senescence of MSCs, including MSC origin (biological niche), donor conditions (age, obesity, diseases, or unknown factors), and culture conditions in vitro. With the rapidly increasing prevalence of diabetes mellitus (DM) and gestational diabetes mellitus (GDM), the effects of hyperglycemia on the senescence of MSCs should be evaluated to improve the application of autologous MSCs. This review aims to present the available data on the senescence of MSCs, its relationship with hyperglycemia, and the strategies to suppress the senescence of MSCs in a hyperglycemic environment.

The relationship between intracellular calcium levels and limb bud chondrogenesis in vitro

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 73-81
Author(s):  
J.A. Bee ◽  
R. Jeffries
Keyword(s):  
Phenotypic Expression ◽  
Culture Conditions ◽  
Limb Bud ◽  
Concentration Effects ◽  
Cartilage Differentiation ◽  
Standard Culture ◽  
The Relationship ◽  
Plateau Level

Under standard culture conditions, chondrogenic expression by stage-21 embryonic chick limb bud mesenchyme is dependent upon high cell plating densities. Alternatively, when cultured in suspension aggregating limb bud cells differentiate exclusively as cartilage. We have previously demonstrated that the aggregation of prechondrogenic limb bud cells is specifically mediated by a Ca2+ -dependent mechanism. In the present paper, we examine the involvement of calcium cations in chondrogenic expression in vitro. During cartilage differentiation, we demonstrate that limb bud cells elevate their intracellular Ca2+ levels to achieve a conserved plateau level. This increase in intracellular Ca2+ levels does not occur in sparse cell cultures, which also fail to demonstrate cartilage differentiation. Although elevation of extracellular Ca2+ concentration effects precocious chondrogenesis, ultimately this is substantially lower than in control cultures. In contrast, elevation of intracellular Ca2+ levels by the addition of 0á1 μm-A23187 readily stimulates precocious and extensive cartilage differentiation. 0á1μm-A23187 initially elevates intracellular Ca2+ levels to that required for cartilage differentiation but this then continues to increase concomitant with a reduction in cartilage nodule size. 10μm-retinoic acid completely inhibits chondrogenesis in vitro and elevates intracellular Ca2+ to particularly high levels. Our data indicate the central role of controlled intracellular Ca2+ levels to normal chondrogenic expression. Deviation from this level by cells that either fail to achieve or that exceed it inhibits subsequent cartilage development, and can cause a loss of phenotypic expression by differentiated cartilage.

In vitro inhibition of UGT1A3, UGT1A4 by ursolic acid and oleanolic acid and drug–drug interaction risk prediction

Xenobiotica ◽  
2016 ◽  
Vol 47 (9) ◽  
pp. 785-792 ◽  
Author(s):  
Hongbo Xie ◽  
Jie Wu ◽  
Dan Liu ◽  
Mingyi Liu ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Drug Interaction ◽  
Risk Prediction ◽  
Ursolic Acid ◽  
Oleanolic Acid ◽  
In Vitro Inhibition ◽  
Drug Drug Interaction

scholarly journals 5-Azacytidine: A Promoter of Epigenetic Changes in the Quest to Improve Plant Somatic Embryogenesis

2018 ◽  
Vol 19 (10) ◽  
pp. 3182 ◽  
Author(s):  
Pedro Osorio-Montalvo ◽  
Luis Sáenz-Carbonell ◽  
Clelia De-la-Peña
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Somatic Embryogenesis ◽  
Regulation Of Gene Expression ◽  
Culture Conditions ◽  
Short Time ◽  
Time Frames ◽  
Different Sources

Somatic embryogenesis (SE) is a widely studied process due to its biotechnological potential to generate large quantities of plants in short time frames and from different sources of explants. The success of SE depends on many factors, such as the nature of the explant, the microenvironment generated by in vitro culture conditions, and the regulation of gene expression, among others. Epigenetics has recently been identified as an important factor influencing SE outcome. DNA methylation is one of the most studied epigenetic mechanisms due to its essential role in gene expression, and its participation in SE is crucial. DNA methylation levels can be modified through the use of drugs such as 5-Azacytidine (5-AzaC), an inhibitor of DNA methylation, which has been used during SE protocols. The balance between hypomethylation and hypermethylation seems to be the key to SE success. Here, we discuss the most prominent recent research on the role of 5-AzaC in the regulation of DNA methylation, highlighting its importance during the SE process. Also, the molecular implications that this inhibitor might have for the increase or decrease in the embryogenic potential of various explants are reviewed.

scholarly journals Macrophage Class A Scavenger Receptor-Mediated Phagocytosis of Escherichia coli: Role of Cell Heterogeneity, Microbial Strain, and Culture Conditions In Vitro

2000 ◽  
Vol 68 (4) ◽  
pp. 1953-1963 ◽  
Author(s):  
Leanne Peiser ◽  
Peter J. Gough ◽  
Tatsuhiko Kodama ◽  
Siamon Gordon
Keyword(s):  
Escherichia Coli ◽  
Host Defense ◽  
Bacterial Strain ◽  
Chinese Hamster Ovary Cells ◽  
Culture Conditions ◽  
E Coli ◽  
Class A

ABSTRACT Macrophage class A scavenger receptors (SR-AI and SR-AII) contribute to host defense by binding polyanionic ligands such as lipopolysaccharide and lipoteichoic acid. SR-A knockout (SR-A−/−) mice are more susceptible to endotoxic shock and Listeria monocytogenes infection in vivo, possibly due to decreased clearance of lipopolysaccharide and microorganisms, respectively. We have used flow cytometry to analyze the role of SR-A and other scavenger-like receptors in phagocytosis of bacteria in vitro. Chinese hamster ovary cells stably transfected with human SR-A bound Escherichia coli and Staphylococcus aureus but ingested few organisms. Primary human monocyte-derived macrophages (Mφ) bound and ingested E. coli more efficiently, and this was partially but selectively blocked by the general SR inhibitor, poly(I). A specific and selective role for SR-A was shown, since bone marrow culture-derived Mφ from SR-A−/− mice ingested fewer E. coli organisms than did wild-type cells, while uptake of antibody-opsonized E. coli was unaffected. SR-A-dependent uptake of E. colivaried with the bacterial strain; ingestion of DH5α and K1 by SR-A−/− Mφ was reduced by 30 to 60% and 70 to 75%, respectively. Phagocytosis and endocytosis via SR-A were markedly down-modulated when Mφ were plated on serum-coated tissue culture plastic compared to bacteriologic plastic, where cell adhesion is mediated by SR-A and CR3, respectively. This paper demonstrates that SR-A can bind and ingest bacteria directly, consistent with a role in host defense in vivo, and highlights the importance of the source of the Mφ, bacterial strain, and culture conditions on receptor function in vitro.

scholarly journals Sucrose and Cytokinin Interactions in Relation to Ethylene and Abscisic Acid Production in the Regulation of Morphogenesis in Pelargonium × hortorum L.H. Bailey In Vitro

2015 ◽  
Vol 57 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Agnieszka Wojtania ◽  
Elżbieta Węgrzynowicz-Lesiak ◽  
Michał Dziurka ◽  
Piotr Waligórski
Keyword(s):  
Abscisic Acid ◽  
Ethylene Production ◽  
Sucrose Concentration ◽  
Fold Increase ◽  
Shoot Formation ◽  
Inhibitory Effect ◽  
Synthesis Inhibitor ◽  
Subculture Period ◽  
Ethylene Action

Abstract The aim of the study was to determine the effect of exogenous sucrose and cytokinin on ethylene production and responsiveness in relation to the shoot formation of Pelargonium × hortorum ‘Bergpalais’ in vitro. Increasing the concentration of sucrose from 15 to 40 g L−1 in medium containing meta-topolin (mT) resulted in a two-fold decrease in the number of shoots and leaves as well as a reduction in ethylene production. The addition of ethylene synthesis inhibitor (AVG) to mT-medium significantly reduced the ethylene production and the shoot growth, but it had no significant influence on the shoot formation. The mT-induced shoot formation was, however, significantly reduced in the presence of ethylene action inhibitor (AgNO3), in a manner dependent on sucrose levels. At the end of the subculture period, increased sucrose concentrations (15–40 g L−1) in the presence of mT and AgNO3 resulted in a 3.7-fold increase in ethylene emission. At the same time, the supply of sucrose caused a 2.8-fold increase in the level of endogenous abscisic acid (ABA). Our results may suggest that the inhibitory effect of high sucrose concentration (30 and 40 g L−1) may depend on its influence on ethylene sensitivity. It also suggests that sucrose-regulation of the shoot formation of Pelargonium in vitro is mediated by ABA.

Competence, determination, and meristemoid plasticity in tobacco organogenesis in vitro

2003 ◽  
Vol 81 (6) ◽  
pp. 611-621 ◽  
Author(s):  
Harbinder S Dhaliwal ◽  
Nicole S Ramesar-Fortner ◽  
Edward C Yeung ◽  
Trevor A Thorpe
Keyword(s):  
Root Formation ◽  
Leaf Explants ◽  
Basal Medium ◽  
Shoot Formation ◽  
Culture Conditions ◽  
Vascular Bundles ◽  
Mesophyll Cells ◽  
Tobacco Leaf ◽  
Organogenesis In Vitro

Tobacco leaf explants can produce both shoots and roots depending on the phytohormones in the medium. These arise directly via meristemoids (meristematic centers), which form distinct primordia and then organs. In this study it was found that shoot primordia arose from the palisade mesophyll cells at the adaxial surface, while root primordia arose from the rib parenchyma cells, near the existing vascular bundles. In studies on competency and determination, it was found that the tobacco leaf explants required 4–6 days in culture on a shoot-inducing medium (SIM) to become determined for shoot formation, while the explants were competent for rooting at excision and needed only 1 day on the root-inducing medium (RIM) to become determined for root formation. Transfer of explants from SIM or RIM to basal medium (BM without phytohormones) and vice versa supported the above findings. Transfer of explants from SIM to RIM and vice versa, delayed the timing of root and shoot formation, but not the position in the explant from which the organs arose. On transfer from SIM to RIM or vice versa, meristemoids that were already determined for shoot or root formation continued to develop, while those not yet determined were inhibited and (or) reverted to parenchymatous tissue. Thus under our culture conditions meristemoids in tobacco leaf explants are not plastic.Key words: competence, determination, meristemoid plasticity, organogenesis, tobacco.

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