scholarly journals Studies on the chromatin of barley leaves during senescence

1968 ◽  
Vol 110 (4) ◽  
pp. 683-686 ◽  
Author(s):  
B. I. Sahai Srivastava
Keyword(s):  
Rna Synthesis ◽  
Cellular Functions ◽  
Hormonal Factor ◽  
Young Leaves ◽  
Barley Leaves ◽  
Advanced Stages ◽  
Deoxyribonuclease Activity

1. The activity of soluble ribonuclease and deoxyribonuclease first declined during senescence, but later increased during advanced stages of senescence. 2. Young leaves had very low ribonuclease or deoxyribonuclease activity associated with the chromatin, but the activity of these enzymes increased progressively during senescence until the leaves died. 3. No significant changes in the composition of chromatin from first seedling leaves of barley plants during aging (from 7 to 25 days) were noted. 4. The amount of RNA synthesized by chromatin in vitro declined as the leaf aged. However, if the loss of RNA due to chromatin-associated ribonuclease was taken into account, the RNA-synthesizing activity of chromatin from senescing (15–16-day-old) leaves appeared to be somewhat higher than that of chromatin from young (7–8-day-old) leaves. In leaves at the terminal stages of senescence (23 days old) the estimates of RNA synthesis by chromatin could not be made owing to complications created by high nuclease activities. 5. It is suggested that senescence may be triggered by a decline in some hormonal factor in leaves, and that the resulting production of chromatin-associated deoxyribonuclease and ribonuclease in increasing proportions may progressively cause increased degradation of DNA and newly synthesized RNA, so that ultimately the cellular functions are impaired and the cells die.

Correlation Between Cellular Functions and Morphological Changes of Human Trophoblast in Vitro

1975 ◽  
Vol 33 ◽  
pp. 600-601
Author(s):  
John C. Garancis ◽  
Robert O. Hussa ◽  
Michael T. Story ◽  
Donald Yorde ◽  
Roland A. Pattillo
Keyword(s):  
Electron Microscopy ◽  
Cellular Proliferation ◽  
Morphological Changes ◽  
Culture Fluid ◽  
Cellular Functions ◽  
Human Trophoblast ◽  
Transmission Electron ◽  
Marked Activity ◽  
Malignant Trophoblast

Human malignant trophoblast cells in continuous culture were incubated for 3 days in medium containing 1 mM N6-O2'-dibutyryl cyclic adenosine 3':5'-monophosphate (dibutyryl cyclic AMP) and 1 mM theophylline. The culture fluid was replenished daily. Stimulated cultures secreted many times more chorionic gonadotropin and estrogens than did control cultures in the absence of increased cellular proliferation. Scanning electron microscopy revealed remarkable surface changes of stimulated cells. Control cells (not stimulated) were smooth or provided with varying numbers of microvilli (Fig. 1). The latter, usually, were short and thin. The surface features of stimulated cells were considerably different. There was marked increase of microvilli which appeared elongated and thick. Many cells were covered with confluent polypoid projections (Fig. 2). Transmission electron microscopy demonstrated marked activity of cytoplasmic organelles. Mitochondria were increased in number and size; some giant forms with numerous cristae were observed.

Development of an Agrobacterium-mediated Transformation System for `Beurre Bosc' Pear

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 461d-461
Author(s):  
Richard L. Bell ◽  
Ralph Scorza ◽  
Chinnathambi Srinivasan
Keyword(s):  
Shoot Proliferation ◽  
Induction Medium ◽  
Shoot Induction ◽  
Transformation System ◽  
Gus Histochemical Assay ◽  
Young Leaves ◽  
Leaf Tissues ◽  
Shoot Induction Medium ◽  
Basal Salts

An efficient regeneration/transformation system was developed for `Beurre Bosc' pear. Young leaves were harvested from in vitro shoots proliferated on a medium containing MS basal salts and 5 BAP, 0.5 μM IBA, and 0.6M3. Shoot regeneration was optimized using a modification of the medium of Chevreau and Leblay (1993). Explants were cultured on shoot induction medium contained 10 μM TDZ and 1 μM IBA for 4 weeks in the dark, and then transfered to a similar, but auxinless, regeneration medium until shoots developed, usually after an additional 4 to 8 weeks. Leaf tissues were transformed by co-cultivation for 3 days with Agrobacterium tumefaciens EHA101 carrying a pGA482 plasmid containing NPTII, GUS, and rolC genes, followed by cultivation on SIM containing 300 mg/L timentin. Putative transgenic plants were selected on shoot induction medium containing 80mg/L kanamycin, and multiplied on shoot proliferation medium. Four clones were confirmed as transgenic using the GUS histochemical assay and Southern blots for the NPTII and rolC genes. Plants of each clone have been rooted and successfully transfered to the greenhouse for further analysis of gene expression.

Investigation of the effect of loratadine and calcium ions on oxidoreductase activity of catalase enzyme

2020 ◽  
Vol 16 ◽  
Author(s):  
Edhem Hasković ◽  
Safija Herenda ◽  
Zehra Halilović ◽  
Snežana Unčanin ◽  
Denis Hasković ◽  
...  
Keyword(s):  
Calcium Ions ◽  
Enzyme Reaction ◽  
Analytical Techniques ◽  
Competitive Inhibitor ◽  
Cellular Functions ◽  
Oxidoreductase Activity ◽  
H1 Antihistamines ◽  
Activity Of Enzymes ◽  
The Given

Background: The Spectrophotometric method is one of the most suitable analytical techniques for testing the activity of enzymes under the influence of various factors. Methods: The effect of H1-antihistamines of loratadine and calcium ions on enzyme catalase under in vitro conditions was investigated in this paper. Results and Discussion: It has been shown that loratadine isa partial inhibitor of catalase, but this effect is diminished in the presence of calcium ions. Calcium as well as other cations are important for many biological and cellular functions. The kidneys play a central role in the homeostasis of these ions. The activity of the catalase enzyme under the given conditions, the type of inhibition,and the kinetic parameters of the enzyme reaction were determined. Conclusion: We concluded that loratadine is a partially competitive inhibitor.

scholarly journals Internalization of Foldamer-Based DNA Mimics through a Site-Specific Antibody Conjugate to Target HER2-Positive Cancer Cells

2021 ◽  
Vol 14 (7) ◽  
pp. 624
Author(s):  
Valentina Corvaglia ◽  
Imène Ait Mohamed Amar ◽  
Véronique Garambois ◽  
Stéphanie Letast ◽  
Aurélie Garcin ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Topoisomerase I ◽  
Ovarian Cancer Cells ◽  
Cellular Functions ◽  
Antibody Drug Conjugate ◽  
Her2 Positive ◽  
Dna Topoisomerase ◽  
Antibody Conjugate ◽  
A Site

Inhibition of protein–DNA interactions represents an attractive strategy to modulate essential cellular functions. We reported the synthesis of unique oligoamide-based foldamers that adopt single helical conformations and mimic the negatively charged phosphate moieties of B-DNA. These mimics alter the activity of DNA interacting enzymes used as targets for cancer treatment, such as DNA topoisomerase I, and they are cytotoxic only in the presence of a transfection agent. The aim of our study was to improve internalization and selective delivery of these highly charged molecules to cancer cells. For this purpose, we synthesized an antibody-drug conjugate (ADC) using a DNA mimic as a payload to specifically target cancer cells overexpressing HER2. We report the bioconjugation of a 16-mer DNA mimic with trastuzumab and its functional validation in breast and ovarian cancer cells expressing various levels of HER2. Binding of the ADC to HER2 increased with the expression of the receptor. The ADC was internalized into cells and was more efficient than trastuzumab at inhibiting their growth in vitro. These results provide proof of concept that it is possible to site-specifically graft high molecular weight payloads such as DNA mimics onto monoclonal antibodies to improve their selective internalization and delivery in cancer cells.

scholarly journals The role of ATP in in vitro vaccinia virus RNA synthesis effects of AMP-PNP and ATP gamma S.

1980 ◽  
Vol 255 (11) ◽  
pp. 5396-5403
Author(s):  
S. Shuman ◽  
E. Spencer ◽  
H. Furneaux ◽  
J. Hurwitz
Keyword(s):  
Vaccinia Virus ◽  
Rna Synthesis ◽  
Virus Rna ◽  
Gamma S

scholarly journals DIFFERENTIATION OF DROSOPHILA CELLS LACKING RIBOSOMAL DNA, IN VITRO

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 429-434
Author(s):  
J James Donady ◽  
R L Seecof ◽  
M A Fox
Keyword(s):  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribosomal Dna ◽  
Rna Synthesis ◽  
Wild Type ◽  
Drosophila Cells

ABSTRACT Drosophila melanogaster embryos that lacked ribosomal DNA were obtained from appropriate crosses. Cells were taken from such embryos before overt differentiation took place and were cultured in vitro. These cells differentiated into neurons and myocytes with the same success as did wild-type controls. Therefore, ribosomal RNA synthesis is not necessary for the differentiation of neurons and myocytes in vitro.

scholarly journals The Extracellular Small Leucine-Rich Proteoglycan Biglycan Is a Key Player in Gastric Cancer Aggressiveness

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1330
Author(s):  
Filipe Pinto ◽  
Liliana Santos-Ferreira ◽  
Marta T. Pinto ◽  
Catarina Gomes ◽  
Celso A. Reis
Keyword(s):  
Clinical Value ◽  
Knock Out ◽  
Angiogenic Potential ◽  
In Vivo Experiments ◽  
Cancer Aggressiveness ◽  
Advanced Stages ◽  
Oncogenic Gene

Biglycan (BGN gene), an extracellular proteoglycan, has been described to be associated with cancer aggressiveness. The purpose of this study was to clarify the clinical value of biglycan as a biomarker in multiple independent GC cohorts and determine the in vitro and in vivo role of biglycan in GC malignant features. We found that BGN is commonly over-expressed in all analyzed cohorts, being associated with disease relapse and poor prognosis in patients with advanced stages of disease. In vitro and in vivo experiments demonstrated that biglycan knock-out GC cells display major phenotypic changes with a lower cell survival, migration, and angiogenic potential when compared with biglycan expressing cells. Biglycan KO GC cells present increased levels of PARP1 and caspase-3 cleavage and a decreased expression of mesenchymal markers. Importantly, biglycan deficient GC cells that were supplemented with exogenous biglycan were able to restore biological features, such as survival, clonogenic and migratory capacities. Our in vitro and in vivo findings were validated in human GC samples, where BGN expression was associated with several oncogenic gene signatures that were associated with apoptosis, cell migration, invasion, and angiogenesis. This study provided new insights on biglycan role in GC that should be taken in consideration as a key cellular regulator with major impact in tumor progression and patients’ clinical outcome.

scholarly journals Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Glucose Utilization ◽  
Actinomycin D ◽  
Hormone Synthesis ◽  
Pituitary Glands ◽  
Hormone Biosynthesis ◽  
Stimulation Of

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

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