scholarly journals Neural Induction in Epidermal Explants in Liquid Medium

1942 ◽  
Vol 19 (1) ◽  
pp. 5-10
Author(s):  
S. C. SHEN
Keyword(s):  
Liquid Medium ◽  
Salt Solution ◽  
Neural Differentiation ◽  
Neural Induction ◽  
Water Soluble ◽  
Experimental Series ◽  
Control Series ◽  
Chemical Action ◽  
Adequate Stimulation

1. Epidermal explants of axolotl gastrulae were cultivated for not less than 10 days in plain salt solution and that containing a water-soluble derivative of a carcinogenetic hydrocarbon, Na-1:2:5:6-dibenzanthracene-α-β-endo-succinate. 2. None of the explants in the control series showed neurulation, while over 60% of those in the experimental series showed definite and extensive neural differentiation. 3. The induced neural structures were in the form of more or less radially symmetrical neural balls, with no regional differentiations. 4. By avoiding the use of a solid implant and thus eliminating any possible mechanical role of an inductor, it proves clearly that, as far as evocation is concerned, the chemical action alone of the evocator constitutes an adequate stimulation.

scholarly journals Nano Zero Valent Iron (nZVI) as an Amendment for Phytostabilization of Highly Multi-PTE Contaminated Soil

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2559
Author(s):  
Maja Radziemska ◽  
Zygmunt M. Gusiatin ◽  
Jiri Holatko ◽  
Tereza Hammerschmiedt ◽  
Andrzej Głuchowski ◽  
...  
Keyword(s):  
Plant Biomass ◽  
Absorption Spectrometry ◽  
Zero Valent Iron ◽  
Festuca Rubra ◽  
Control Series ◽  
Flame Atomic Absorption ◽  
Zn Content ◽  
Nano Zero Valent Iron ◽  
Average Plant

In recent years, a lot of attention has been given to searching for new additives which will effectively facilitate the process of immobilizing contaminants in the soil. This work considers the role of the enhanced nano zero valent iron (nZVI) strategy in the phytostabilization of soil contaminated with potentially toxic elements (PTEs). The experiment was carried out on soil that was highly contaminated with PTEs derived from areas in which metal waste had been stored for many years. The plants used comprised a mixture of grasses—Lolium perenne L. and Festuca rubra L. To determine the effect of the nZVI on the content of PTEs in soil and plants, the samples were analyzed using flame atomic absorption spectrometry (FAAS). The addition of nZVI significantly increased average plant biomass (38%), the contents of Cu (above 2-fold), Ni (44%), Cd (29%), Pb (68%), Zn (44%), and Cr (above 2-fold) in the roots as well as the soil pH. The addition of nZVI, on the other hand, was most effective in reducing the Zn content of soil when compared to the control series. Based on the investigations conducted, the application of nZVI to soil highly contaminated with PTEs is potentially beneficial for the restoration of polluted lands.

scholarly journals Did Cyclic Metaphosphates Have a Role in the Origin of Life?

2021 ◽  
Author(s):  
Thomas Glonek
Keyword(s):  
Organic Molecules ◽  
Water Soluble ◽  
Holliday Junction ◽  
Additional Energy ◽  
Condensed Phosphate ◽  
Geological Processes ◽  
The Origin Of Life ◽  
Complex Forms ◽  
Self Replication

AbstractHow life began still eludes science life, the initial progenote in the context presented herein, being a chemical aggregate of primordial inorganic and organic molecules capable of self-replication and evolution into ever increasingly complex forms and functions.Presented is a hypothesis that a mineral scaffold generated by geological processes and containing polymerized phosphate units was present in primordial seas that provided the initiating factor responsible for the sequestration and organization of primordial life’s constituents. Unlike previous hypotheses proposing phosphates as the essential initiating factor, the key phosphate described here is not a polynucleotide or just any condensed phosphate but a large (in the range of at least 1 kilo-phosphate subunits), water soluble, cyclic metaphosphate, which is a closed loop chain of polymerized inorganic phosphate residues containing only phosphate middle groups. The chain forms an intrinsic 4-phosphate helix analogous to its structure in Na Kurrol’s salt, and as with DNA, very large metaphosphates may fold into hairpin structures. Using a Holliday-junction-like scrambling mechanism, also analogous to DNA, rings may be manipulated (increased, decreased, exchanged) easily with little to no need for additional energy, the reaction being essentially an isomerization.A literature review is presented describing findings that support the above hypothesis. Reviewed is condensed phosphate inorganic chemistry including its geological origins, biological occurrence, enzymes and their genetics through eukaryotes, polyphosphate functions, circular polynucleotides and the role of the Holliday junction, previous biogenesis hypotheses, and an Eoarchean Era timeline.

The role of calcium in the increase in flocculence of yeast growing in the presence of copper

1965 ◽  
Vol 162 (989) ◽  
pp. 555-566 ◽  
Keyword(s):  
Liquid Medium ◽  
Cell Cultures ◽  
Chloride Solution ◽  
Liquid Copper ◽  
Acquired Resistance ◽  
Calcium Chloride Solution ◽  
Copper Resistance ◽  
Liquid Cultures ◽  
Selection Of

Growth in the presence of inhibitory concentrations of copper enhances the tendency of yeast to flocculate. Many yeasts will not flocculate unless calcium is included in the growth medium and Guinness strain 522 used in the present work required a relatively large amount. Single cell cultures may undergo variation during subculture, resulting in the production of a large number of variants (Chester 1963). The cells of these variants differ considerably in their ability to adhere together. Flocculation variants of strain 522 differed among themselves in the amount of calcium necessary for flocculation, the most flocculent variants requiring least calcium. Washed cells of the more flocculent yeasts removed more calcium from a calcium chloride solution than did those with lesser powers of adhesion. In a copper medium con­taining calcium the more flocculent variants replaced the less flocculent. Calcium protected cells from copper and the more flocculent variants enjoyed most protection. All variants acquired resistance to copper during growth in the copper medium. Despite the selection of the more flocculent yeasts during growth in liquid medium, their copper resistance was less than that of the less flocculent yeasts. When calcium was added to the liquid copper medium, cultures developed less resistance. It is concluded that the less flocculent cells, having less protection by calcium, were exposed to what was effectively a greater concentration of copper and therefore became more resistant. This greater resistance did not enable these cells to compete with the flocculent cells in liquid cultures.

The biological activity of glucagon–phospholipid complexes

1983 ◽  
Vol 61 (7) ◽  
pp. 688-691 ◽  
Author(s):  
J. J. Liepnieks ◽  
P. Stoskopf ◽  
E. A. Carrey ◽  
C. Prosser ◽  
R. M. Epand
Keyword(s):  
Biological Activity ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Bovine Brain ◽  
Water Soluble ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Dimyristoyl Phosphatidylcholine ◽  
Lipoprotein Complex ◽  
Stimulation Of

Glucagon can form water-soluble complexes with phospholipids. The incorporation of glucagon into these lipoprotein particles reduces the biological activity of the hormone. The effect is observed only at temperatures below the phase transition temperature of the phospholipid and results in a decreased stimulation of the adenylate cyclase of rat liver plasma membranes by the lipoprotein complex as compared with the hormone in free solution. Two- to five-fold higher concentrations of glucagon are required for half-maximal stimulation of adenylate cyclase when the hormone is complexed with dimyristoyl phosphatidylcholine, dipalmitoyl phosphatidylcholine, or bovine brain sphingomyelin. A possible role of lipoprotein-associated hormones in the development of insulin resistance is discussed.

scholarly journals An Essential Role of the CAAT/Enhancer Binding Protein-α in the Vitamin D-Induced Expression of the Human Steroid/Bile Acid-Sulfotransferase (SULT2A1)

2006 ◽  
Vol 20 (4) ◽  
pp. 795-808 ◽  
Author(s):  
Chung S. Song ◽  
Ibtissam Echchgadda ◽  
Young-Kyo Seo ◽  
Taesung Oh ◽  
Soyoung Kim ◽  
...  
Keyword(s):  
Vitamin D ◽  
Binding Site ◽  
Essential Role ◽  
Binding Protein ◽  
Water Soluble ◽  
Induced Expression ◽  
Composite Element ◽  
Deoxyribonuclease I ◽  
Enhancer Binding Protein

Abstract The vitamin D receptor (VDR) regulates steroid and drug metabolism by inducing the genes encoding phase I and phase II enzymes. SULT2A1 is a liver- and intestine-expressed sulfo-conjugating enzyme that converts the alcohol-OH of neutral steroids, bile acids, and drugs to water-soluble sulfated metabolites. 1α,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] induces SULT2A1 gene transcription after the recruitment of VDR to the vitamin D-responsive chromatin region of SULT2A1. A composite element in human SULT2A1 directs the 1,25-(OH)2D3-mediated induction of natural and heterologous promoters. This element combines a VDR/retinoid X receptor-α-binding site [vitamin D response element (VDRE)], which is an imperfect inverted repeat 2 of AGCTCA, and a CAAT/enhancer binding protein (C/EBP)-binding site located 9 bp downstream to VDRE. The binding sites were identified by EMSA, antibody supershift, and deoxyribonuclease I footprinting. C/EBP-α at the composite element plays an essential role in the VDR regulation of SULT2A1, because 1) induction was lost for promoters with inactivating mutations at the VDRE or C/EBP element; 2) SULT2A1 induction by 1,25-(OH)2D3 in C/EBP-α-deficient cells required the expression of cotransfected C/EBP-α; and 3) C/EBP-β did not substitute for C/EBP-α in this regulation. VDR and C/EBP-α were recruited concurrently to the composite element along with the coactivators p300, steroid receptor coactivator 1 (SRC-1), and SRC-2, but not SRC-3. VDR and C/EBP-α associated endogenously as a DNA-dependent, coimmunoprecipitable complex, which was detected at a markedly higher level in 1,25-(OH)2D3-treated cells. These results provide the first example of the essential role of the interaction in cis between C/EBP-α and VDR in directing 1,25-(OH)2D3-induced expression of a VDR target gene.

The Emerging Role of Nanosuspensions for Drug Delivery and Stability

2021 ◽  
Vol 12 ◽  
Author(s):  
Hitesh Kumar Dewangan
Keyword(s):  
Water Solubility ◽  
Size Range ◽  
Aqueous Solubility ◽  
Active Surface ◽  
Water Soluble ◽  
Active Surface Area ◽  
Specific Interest ◽  
Advanced Therapies ◽  
Processing Techniques

: Poor solubility of some medicinal compounds is a serious challenge that can be addressed by using a nano-suspension for improved delivery. The nanoparticles enhance the bioavailability along with the aqueous solubility of the drug, which is accomplished by increasing the active surface area of the drug. The gained attention of the nanosuspension is due to its stabilization facility, which is achieved by polymers, such as polyethylene glycol (PEG), having a particular size range of 10 - 100 nm. Hence, these nanoparticles have the capacity of binding to the targeted with very low damage to the healthy tissues. These are prepared by various methods, such as milling, high-pressure homogenization, and emulsification, along with melt emulsification. Moreover, surface modification and solidification have been used to add specific properties to the advanced therapies as post-processing techniques. For many decades, it has been known that water solubility hampers the bioavailability and not all drugs are water-soluble. In order to combat this obstacle, nanotechnology has been found to be of specific interest. For elevating the bioavailability by increasing the dissolution rate, the methodology of reduction of the associated drug particles into their subsequent submicron range is incorporated. For oral and non-oral administration, these nanosuspension formulations are used for the delivery of drugs.

Neural induction and the structure of the target cell surface

Development ◽  
1982 ◽  
Vol 70 (1) ◽  
pp. 171-187
Author(s):  
A. M. Duprat ◽  
L. Gualandris ◽  
P. Rouge
Keyword(s):  
Cell Surface ◽  
Structural Integrity ◽  
Neural Induction ◽  
Active Role ◽  
Target Cells ◽  
Similar Treatment ◽  
Structural Modifications ◽  
Pleurodeles Waltl

Lectins (SBA and PSA) were used to provoke crowding and structural modifications of the presumptive ectoderm cell surface in order to investigate the role of the membrane organization of the competent target cells in neural induction. Are specific characteristics of the cell surface essential for this phenomenon to occur? From amphibian gastrulae, it is possible to obtain neural induction in vitro by association of presumptive ectoderm (target cells) with chordamesoderm (inductor tissue): 4 h of contact is sufficient in Pleurodeles waltl for transmission of the inductive signal. Very quickly, the treatment of the normal ectoderm by lectins (SBA-FITC or PSA-FITC) provoked surface modifications. Lectin-treatment (50 µg ml1−, 30 min) of presumptive ectoderm did not result in any neural induction. Lectin-treatment (50 µg ml1−, 30 min) of presumptive ectoderm previous to its association with the natural inductor for 4 h, disturbed the phenomenon: no induction. Similar treatment followed by association with the inductor for 24 h: induction. Treatment of SBA or PSA with their respective hapten inhibitors prior to addition to ectodermal cells completely blocked the suppressive effects on induction. The structural integrity of the membrane of competent target cells is necessary for neural induction to occur. The cell membrane could thus play, directly or indirectly, an active role in the specificity of this process

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