scholarly journals The nature of conditioning nutrients for human malignant melanoma cultures

1983 ◽  
Vol 62 (1) ◽  
pp. 249-266
Author(s):  
K.A. Ellem ◽  
G.F. Kay
Keyword(s):  
Molecular Weight ◽  
Cell Density ◽  
Cell Attachment ◽  
Cell Types ◽  
Fresh Medium ◽  
Low Molecular Weight ◽  
High Concentration ◽  
Cell Content ◽  
Human Malignant Melanoma ◽  
Serum Factors

From a human melanoma line (MM96), showing some dependence of its rate of growth and cell attachment on serum concentration, sublines were selected for even greater dependence on serum factors. These sublines were used to identify the production of substances by other melanoma cells in culture that would supplement or replace the requirement for serum. Most of the sublines showed higher colony-forming efficiency in medium conditioned by one of several cell types in the presence of a low concentration of serum (2.5%) compared with fresh medium containing a high concentration of serum (10%). The conditioning factor(s) were found to be moderately heat-stable, nonlipophilic, and to be of low molecular weight (less than or greater than 400). Screening of a variety of non-essential low molecular weight nutrients, which have been reported to potentiate the growth of a variety of cell types in low-density culture, was positive for the MM96 sublines only for pyruvate. In particular, L-alanine, L-serine, putrescine and alpha MSH (melanocyte-stimulating hormone) were ineffective. Despite the problems of comparing conditioned media with fresh medium, a reasonable correlation between the stimulatory effect and the cell content of added 2-oxocarboxylates was apparent. As would be anticipated, MM96 cultures showed a population density-dependent enhancement of growth up to a cell density of 2 to 4 × 10(4) cells cm-2. Further increase in the initial cell density of these cultures led to a decline in growth rate. An important additional observation was that simple dilution of the ingredients of RPMI1640 with phosphate-buffered saline or Hanks' balanced salt solution led to a reversal of growth inhibition accompanying a serum shift-down.

A ligand-receptor model for the cohesive behaviour of Dictyostelium discoideum axenic cells

1979 ◽  
Vol 37 (1) ◽  
pp. 157-167
Author(s):  
A.R. Jaffe ◽  
A.P. Swan ◽  
D.R. Garrod
Keyword(s):  
Molecular Weight ◽  
Stationary Phase ◽  
Chelating Agent ◽  
Cell Types ◽  
Low Molecular Weight ◽  
Receptor Model ◽  
Phase Growth ◽  
Developmentally Regulated ◽  
Receptor System ◽  
Contact Sites

Axenically grown cells of D. discoideum Ax-2 harvested in the log phase of growth, cohere rapidly when shaken in phosphate buffer. After 3.5 days in the stationary phase of growth, cells become completely non-cohesive. Although they do not stick to each other, stationary phase cells do stick to both log phase cells and aggregation-competent cells. The cohesion of stationary phase cells with these other 2 cell types is inhibited by both EDTA and the low-molecular-weight factor which we have previously demonstrated in stationary-phase growth medium. There is a decline in the sensitivity of slime mould cell cohesion to the low-molecular-weight inhibitory factor as the cells become aggregation-competent. This effect parallels the developmentally-regulated decline in sensitivity to EDTA. The low-molecular-weight inhibitor is not a chelating agent, however. The effect of the inhibitor seems to be specifically against contact sites-B mediated cohesion. We suggest that the simplest cohesive mechanism which can explain our results, is that the EDTA-sensitive cohesion of log phase cells could be dependent on a ligand-receptor system.

Effect of low molecular weight human serum factors and human somatomedin peptides on human lymphocyte cultures

1982 ◽  
Vol 57 (1) ◽  
pp. 129-137
Author(s):  
MH Heulin ◽  
M Artur ◽  
J Straczek ◽  
F Belleville ◽  
P Nabet ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Human Serum ◽  
Human Lymphocyte ◽  
Low Molecular Weight ◽  
Serum Factors ◽  
Lymphocyte Cultures

STUDIES ON SMALL MOLECULAR WEIGHT ADHESION PROTEINS (SAPs) FROM CONNECTIVE TISSUES

1987 ◽  
Author(s):  
S Wasi ◽  
P Alles ◽  
D Gauthier ◽  
U Bhargava ◽  
J Farsi ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polyclonal Antibody ◽  
Type I Collagen ◽  
Cell Attachment ◽  
Binding Capacity ◽  
Guanidine Hydrochloride ◽  
Cell Types ◽  
Type I ◽  
Cell Binding ◽  
Connective Tissues

We have identified a family of low molecular weight proteins with cell attachment properties in a variety of soft and mineralised connective tissues (Wong et al., Biochem. J. 232, 119, 1985). For further characterisation of these proteins we extracted porcine bones with 4 M guanidine hydrochloride and purified the proteins on a series of gel filtration columns The purifed SAPs comprise three bands with Mr -14 000 -17 000. All three proteins bound to heparin-sepahrose in both the presence and absence of 4M urea, and when eluted with 2 M NaCl they retained their cell binding capacity. These proteins promoted the adhesion and spreading of a variety of cell types, including normal fibroblasts, osteoblasts, and epithelial cells, and tumour (osteosarcoma) cells. On Western blotting SAPs did not cross-react with antibodies against fibronectin, laminin or type I collagen; however, they were recognised by a monoclonal antibody to human vitronectin, a polyclonal antibody to bovine vitronectin and polyclonal antibody to human somatomedin B. Dose response experiments indicated that maximum attachment of human gingival fibroblasts occurred in the presence or absence of fetal bovine serum on wells precoated with 2.5 μg/cm2 of SAPs. Attachment of cells to these proteins was partially inhibited by the synthetic pentapeptide Gly-Arg-Gly-Asp-Ser. Utilising the nitrocellulose cell binding assay of Hayman et al (J. Cell. Biol. 95, 20, 1982), the cell attachment to these proteins could be completely inhibited by heparin (100 units/mL) whereas up to 1000 units/mL of heparin had no inhibitory effect on cell attachment to fibronectin and vitronectin. The occurrence of these proteins in a variety of connective tissues and their recognition by different cell types may reflect their general biological role in adhesive mechanisms in both hard and soft connective tissues. Currently, we are investigating the relationship between SAPs and vitronectin, since it is possible that SAPs represent a tissue-processed form of vitronectin or may be novel attachment proteins with regions of homology with vitronectin

Photosynthesis and metabolism of marine algae. VIII. Incorporation of 14C into the polysaccharides metabolized by Fucus vesiculosus during pulse labeling experiments

1972 ◽  
Vol 50 (1) ◽  
pp. 191-197 ◽  
Author(s):  
R. G. S. Bidwell ◽  
Elizabeth Percival ◽  
Berit Smestad
Keyword(s):  
Molecular Weight ◽  
Sequential Extraction ◽  
Marine Algae ◽  
Alginic Acid ◽  
Fucus Vesiculosus ◽  
Fresh Medium ◽  
Low Molecular Weight ◽  
Acid Extract ◽  
Highly Active ◽  
Residual Material

Samples of Fucus vesiculosus fronds were allowed to assimilate 14CO2 for 10 min and 3 h. In a second experiment fronds were allowed to grow for 10 min in 14CO2 and were then transferred to fresh medium containing 12CO2. Samples were taken immediately, after 30 min, and after 2 h. Sequential extraction and fractionation of the polysaccharides from each of the five samples gave 14C-labeled laminaran, xylogalactofucoglucuronan (A), xyloglucuronogalactofucan (B) (these polysaccharides are named in the order of the increasing proportions of their constituent sugars), fucoidan (C), alginic acid, and residual polysaccharide material containing mainly glucose with some galactose. The activities of each of the polysaccharides, the residual material, and their constituent sugars were measured. Highly active low molecular weight carbohydrates, present in the acid extract, are the suggested precursors of the polysaccharides. The fucose-containing polysaccharides represent the extremes of a family of polymers; it is postulated from these studies that (A) is transformed into fucoidan via polysaccharide (B) in this alga.

scholarly journals Organic acids effects on desorption of heavy metals from a contaminated soil

2006 ◽  
Vol 63 (3) ◽  
pp. 276-280 ◽  
Author(s):  
Clístenes Williams Araújo do Nascimento
Keyword(s):  
Heavy Metals ◽  
Molecular Weight ◽  
Citric Acid ◽  
Organic Acids ◽  
Low Molecular Weight ◽  
High Biomass ◽  
High Concentration ◽  
Accumulation Of Metals ◽  
Pb Concentration ◽  
Oxalic Acids

Phytoremediation of heavy metals is a biotechnology that extracts metals from soils and transfer them to plant. As hyperaccumulator species have demonstrated low potential for commercial phytoextraction, synthetic chelates have been successfully used to induce accumulation of metals by high-biomass plants. However, they pose serious environmental drawbacks regarding excessive amount of metals solubilized. In search for synthetic chelate-alternatives, this paper evaluate the performance of DTPA, EDTA, citric acid, oxalic acid, vanillic acid, and gallic acid in desorbing Cd, Pb, Zn, Cu, and Ni from soil. DTPA and EDTA were highly effective in desorbing Cd, Pb, Zn, Cu, and Ni from soil. However, the excessively high concentration of metals brought in solution by such chelates limits their application in the field. Citric and oxalic acids desorbed substantial quantities of Zn, Cu, and Ni if applied at 10 or 20 mmol kg-1. At the 20 mmol kg-1 dose, vanillic and gallic acids solubilized significant amounts of Zn, Ni, and Cd from soil. None of the tested low molecular weight organic acids substantially increased the Pb concentration in soil solution.

Increased growth stimulation of fibroblasts from diabetics by diabetic serum factors of low molecular weight

1980 ◽  
Vol 37 (2) ◽  
pp. 311-317 ◽  
Author(s):  
T. Koschinsky ◽  
C.E. Bünting ◽  
B. Schwippert ◽  
F.A. Gries
Keyword(s):  
Molecular Weight ◽  
Growth Stimulation ◽  
Low Molecular Weight ◽  
Serum Factors ◽  
Stimulation Of

scholarly journals Use of Tri-Chloroacetic Acid /Acetone/polyethylene glycol for protein purification from HIV-1 infected human plasma

2019 ◽  
Author(s):  
Sushanta Kumar Barik ◽  
Keshar Kunja Mohanty ◽  
Deepa Bisht ◽  
Partha Sarathi Mohanty ◽  
Shripad Patil ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Protein Purification ◽  
Human Plasma ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
High Concentration ◽  
Low Concentration ◽  
Low Molecular Weight Proteins ◽  
Hiv 1

Abstract Human plasma contains high amount of abundant proteins like albumin and globulin. Normally, the proteins having potential for biomarkers are present in very low concentration in human plasma. To resolve the low concentration proteins in polyacrylamide gel, the removal of high abundant proteins from plasma are very essential. Polyethylene glycol is a nontoxic, water soluble synthetic polymer has several applications in chemical and biomedical industries. Various molecular variants of poly ethylene glycol is available and used in protein purification. The mechanism behind the use of high concentration of polyethylene glycol is it binds the molecule in more compact or interpenetrates forming a gel like network surrounding the molecule. Polyethylene glycol -6000 removes the high abundant proteins like Albumin and Globulin in the HIV -1 infected plasma samples and concentrates the low molecular weight proteins as the low molecular weight proteins are essential in biomarker study.

Modification to AOAC Official Methods 2009.01 and 2011.25 to Allow for Minor Overestimation of Low Molecular Weight Soluble Dietary Fiber in Samples Containing Starch

2014 ◽  
Vol 97 (3) ◽  
pp. 896-901 ◽  
Author(s):  
Barry V McCleary
Keyword(s):  
Molecular Weight ◽  
Small Intestine ◽  
Dietary Fiber ◽  
Low Molecular Weight ◽  
High Concentration ◽  
Soluble Dietary Fiber ◽  
Total Dietary Fiber ◽  
Aoac Official ◽  
Proposed Modification ◽  
Hydrolysis Of

Abstract AOAC Official Methods 2009.01 and 2011.25 have been modified to allow removal of resistant maltodextrins produced on hydrolysis of various starches by the combination of pancreatic α-amylase and amyloglucosidase (AMG) used in these assay procedures. The major resistant maltodextrin, 63,65-di-α-D-glucosyl maltopentaose, is highly resistant to hydrolysis by microbial α-glucosidases, isoamylase, pullulanase, pancreatic, bacterial and fungal α-amylase and AMG. However, this oligosaccharide is hydrolyzed by the mucosal α-glucosidase complex of the pig small intestine (which is similar to the human small intestine), and thus must be removed in the analytical procedure. Hydrolysis of these oligosaccharides has been by incubation with a high concentration of a purified AMG at 60°C. This incubation results in no hydrolysis or loss of other resistant oligosaccharides such as FOS, GOS, XOS, resistant maltodextrins (e.g., Fibersol 2) or polydextrose. The effect of this additional incubation with AMG on the measured level of low molecular weight soluble dietary fiber (SDFS) and of total dietary fiber in a broad range of samples is reported. Results from this study demonstrate that the proposed modification can be used with confidence in the measurement of dietary fiber.

scholarly journals α-Poly-l-lysine functions as an adipogenic inducer in 3T3-L1 preadipocytes

Amino Acids ◽  
2021 ◽  
Author(s):  
Kyeong Won Lee ◽  
Young Jun An ◽  
Janet Lee ◽  
Jung-Hyun Lee ◽  
Hyung-Soon Yim
Keyword(s):  
Molecular Weight ◽  
Insulin Signaling ◽  
Adipocyte Differentiation ◽  
Cell Attachment ◽  
Underlying Mechanism ◽  
High Concentration ◽  
Expansion Phase ◽  
Regulatory Pathways ◽  
Mitotic Clonal Expansion ◽  
Positive Effect

Abstractα-Poly-l-lysine (PLL) has been used for various purposes such as cell attachment, immunization, and molecular delivery, and is known to be cytotoxic to several cell lines. Here, we studied the effect of PLL on the adipogenesis of 3T3-L1 cells and investigated the underlying mechanism. Differentiation media containing PLL with a molecular weight (MW) greater than 4 kDa enhanced lipid droplet formation and increased adipogenic marker levels, indicating an increase in adipocyte differentiation. PLL with a molecular weight between 30 and 70 kDa was more effective than PLL of other sizes in 3T3-L1 cell differentiation. Moreover, PLL induced 3T3-L1 adipogenesis in insulin-free adipocyte differentiation medium. Incubation with insulin and PLL exhibited greater adipogenesis than insulin treatment only even at a high concentration. PLL stimulated insulin signaling and augmented the signaling pathway when it was added with insulin. While PLL did not activate the glucocorticoid receptor, which is phosphorylated by dexamethasone (DEX), it showed a positive effect on the cAMP signal pathway when preadipocytes were treated with PLL and 3-isobutyl-1-methylxanthine (IBMX). Consistent with these results, incubation with PLL and DEX without IBMX induced adipocyte differentiation. We also observed that the mitotic clonal expansion phase was the critical stage in adipogenesis for inducing the effects of PLL. These results suggest that PLL functions as an adipogenic inducer in 3T3-L1 preadipocytes and PLL has a direct effect on insulin signaling, one of the main regulatory pathways.

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