Free cell suspensions from rat placental tissue: Metabolism of pregnenolone-4-14C and progesterone-4-14C

1974 ◽  
Vol 30 (4) ◽  
pp. 438-439 ◽  
Author(s):  
Irena Dziadkowiec ◽  
R. Rembiesa
Keyword(s):  
Placental Tissue ◽  
Free Cell ◽  
Cell Suspensions ◽  
Tissue Metabolism

Preparation and characterization of free cell suspensions from the immature rat uterus

Biochemistry ◽  
1973 ◽  
Vol 12 (2) ◽  
pp. 297-306 ◽  
Author(s):  
David Williams ◽  
Jack Gorski
Keyword(s):  
Free Cell ◽  
Cell Suspensions ◽  
Rat Uterus ◽  
Immature Rat

Effects of growth substances on the protoplasmic drought tolerance of leaf cells of the resurrection grass, Sporobolus stapfianus

2001 ◽  
Vol 28 (11) ◽  
pp. 1115 ◽  
Author(s):  
Hamid R. Ghasempour ◽  
Esther M. Anderson ◽  
Donald F. Gaff
Keyword(s):  
Drought Tolerance ◽  
Desiccation Tolerance ◽  
Free Cell ◽  
Growth Substance ◽  
Cell Suspensions ◽  
Individual Plant ◽  
Severe Drought ◽  
Growth Substances ◽  
Sporobolus Stapfianus ◽  
Suspended Cells

Hydrated leaves of the resurrection grass Sporobolus stapfianus Gandoger are not desiccation tolerant, but moderate to severe drought stress can induce their desiccation tolerance while the leaves remain attached to drying intact plants. Free-cell suspensions prepared from fully turgid leaves of S. stapfianus were also found to be desiccation-sensitive. In this study a sensitive assay was developed to determine the effect of exogenous substances on the protoplasmic drought tolerance (PDT) of cell suspensions. Suspended cells were incubated with a wide variety of individual plant growth substances over a range of concentrations. After the incubation, the protoplasmic drought tolerance at each concentration of each substance was determined osmotically. Brassinolide (BR) and methyljasmonic acid (MJA), applied separately, gave the greatest effect — each improved PDT by approximately 6 MPa, compared with controls incubated without growth substances. Exogenous abscisic acid (ABA) improved the PDT of S. stapfianus only slightly (about 1 MPa). Salicylic acid (SA), 1-aminocyclopropane–1-carboxylic acid (ACC), ethephon, gibberellic acid (GA), kinetin (KN) andN 6 -(2-isopentyl)adenine (2ip) each improved PDT by ca 1.5 MPa. Indoleacetic acid (IAA) had no effect, and zeatin (ZN) had a deleterious effect on PDT. Incubation of suspended cells in combinations of two growth substances (MJA with ABA, ACC, BR, GA, IAA or KN; BR with ABA) produced no evidence of synergism, or in most cases, even of additive effects of the tested substances. ABA, BR and MJA (applied separately) stimulated the synthesis of numerous specific proteins. Each growth substance stimulated the synthesis of differing proteins, with four exceptions. This investigation raises the possibility that BR and MJA may play a role in a chain of events which leads eventually to the induction of desiccation tolerance in leaves of S. stapfianus. The effects on cell PDT observed in this study, while large, were insufficient to account for the remarkable improvement observed in the PDT of S. stapfianus leaves attached to drying plants.

scholarly journals Reference-Based Versus Reference-Free Cell Type Estimation In DNA Methylation Studies Using Human Placental Tissue

2021 ◽  
Author(s):  
Linda Dieckmann ◽  
Cristiana Cruceanu ◽  
Marius Lahti-Pulkkinen ◽  
Jari Lahti ◽  
Tuomas Kvist ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Human Placenta ◽  
Disease Risk ◽  
Placental Tissue ◽  
Predictive Performance ◽  
Cell Types ◽  
Free Cell ◽  
Estimation Methods ◽  
Cell Type ◽  
Chorion Villus

Abstract The placenta is a central organ during early development, influencing trajectories of health and disease. DNA methylation (DNAm) studies of human placenta improve our understanding of how its function relates to disease risk. However, DNAm studies can be biased by cell type heterogeneity, so it is essential to control for this in order to reduce confounding and increase precision. Computational cell type deconvolution approaches have proven to be very useful for this purpose. For human placenta, however, an assessment of the performance of these estimation methods is still lacking. Here, we compare the predictive performance of reference-based versus reference-free estimated proportions of cell types from genome-wide DNAm in placental samples taken at birth and from chorion villus biopsies early in pregnancy using three independent studies comprising over 1,000 samples. We found both reference-free and reference-based estimated cell type proportions to have predictive value for DNAm, however, reference-based cell type estimation outperformed reference-free estimation for the majority of data sets. Reference-based cell type estimations mirror previous histological knowledge on changes in cell type proportions through gestation. Further, CpGs whose variation in DNAm was largely explained by reference-based estimated cell type proportions were in the proximity of genes that are highly tissue-specific for placenta. This was not the case for reference-free estimated cell type proportions. We provide a list of these CpGs as a resource to help researchers to interpret results of existing studies and improve future DNAm studies of human placenta.

The kinetics of metal uptake by microbial biomass: implications for the design of a biosorption reactor

1998 ◽  
Vol 38 (6) ◽  
pp. 279-286 ◽  
Author(s):  
T.J. Butter ◽  
L.M. Evison ◽  
I.C. Hancock ◽  
F.S. Holland
Keyword(s):  
Retention Time ◽  
Metal Uptake ◽  
Copper Ions ◽  
Plug Flow ◽  
Settling Tank ◽  
Copper Ion ◽  
Biomass Concentration ◽  
Free Cell ◽  
Cell Suspensions ◽  
Kinetics Of

The kinetics of copper ion biosorption by free cell suspensions of inactivated Penicillium biomass was investigated. During the first 15 seconds of the metal uptake reaction copper biosorption was extremely rapid, becoming progressively slower until equilibrium was achieved. At a biomass concentration of 5.48 g dry weight/l, the copper biosorption reaction reached approximately 90% of the equilibrium position in one minute. This is in contrast with biosorption onto immobilised biomass which is known to take up to 24 hours or longer to reach equilibrium. However, the conventional reactor design for free cell suspensions, the stirred tank, may make inefficient use of the equipment and process due to the extended retention time. A plug-flow biosorption reactor with a limited retention time has been developed and demonstrated in the laboratory. The biomass and metal solution were mixed together using static in-line mixers and pumped along a length of pipe before discharging the mixed liquor into a settling tank to achieve phase separation. Desorption of the bound copper ions was achieved by drawing an eluant solution through metal-loaded biomass immobilised as a filter cake. The combination of metal uptake using free cells, and desorption using immobilised cells, optimises the kinetic and mass transfer effects for both processes and minimises the equipment requirements.

Investigations on ploidy levels of haploid and diploid callus and cell suspension cultures of Datura innoxia Mill

1980 ◽  
Vol 44 (1) ◽  
pp. 365-373
Author(s):  
R. Kibler ◽  
J. Blaschke ◽  
E. Forche ◽  
K.H. Neumann
Keyword(s):  
Cell Division ◽  
Cell Suspension ◽  
Ploidy Level ◽  
Cell Suspension Cultures ◽  
Callus Cultures ◽  
Free Cell ◽  
Cell Suspensions ◽  
Datura Innoxia ◽  
Ploidy Levels ◽  
C Value

Using haploid and diploid Datura innoxia Mill, callus cultures and cell suspensions it was shown that meristematic material usually attains the lowest possible C-value of a given ploidy level. Parenchyma material of callus cultures, however, indicates a broad scattering of C-values up to 16 C, which is paralleled by C-value distribution of the free cell fraction in actively dividing cell suspensions. In these suspensions, cell division activity seems to be restricted to small meristem-like clusters.

A pre-embedding, protein a-gold immunolabelling technique for cytocentrifuged cell monolayers for lm and tem

1986 ◽  
Vol 44 ◽  
pp. 220-221
Author(s):  
K. Chien ◽  
I.P. Shintaku ◽  
A.F. Sassoon ◽  
R.L. Van de Velde ◽  
R. Heusser
Keyword(s):  
Cell Surface ◽  
Staining Method ◽  
Protein A ◽  
Surface Antigens ◽  
Cell Suspensions ◽  
Cellular Morphology ◽  
Cellular Phenotype ◽  
Cell Surface Antigens ◽  
Cell Monolayers ◽  
Diagnostic Histopathology

Identification of cellular phenotype by cell surface antigens in conjunction with ultrastructural analysis of cellular morphology can be a useful tool in the study of biologic processes as well as in diagnostic histopathology. In this abstract, we describe a simple pre-embedding, protein A-gold staining method which is designed for cell suspensions combining the handling convenience of slide-mounted cell monolayers and the ability to evaluate specimen staining specificity prior to EM embedding.

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