scholarly journals Chiral acidic amino acids induce chiral hierarchical structure in calcium carbonate

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Wenge Jiang ◽  
Michael S. Pacella ◽  
Dimitra Athanasiadou ◽  
Valentin Nelea ◽  
Hojatollah Vali ◽  
...  
Keyword(s):  
Amino Acids ◽  
Calcium Carbonate ◽  
Hierarchical Structure ◽  
Acidic Amino Acids

Controlled preparation of micro–nano hierarchical hollow calcium carbonate microspheres by pressurized-CO2 carbonization and their CaCO3:Eu3+ photoluminescence properties

CrystEngComm ◽  
2021 ◽  
Vol 23 (16) ◽  
pp. 3033-3042
Author(s):  
Liubin Shi ◽  
Mingde Tang ◽  
Yaseen Muhammad ◽  
Yong Tang ◽  
Lulu He ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Calcium Hydroxide ◽  
Hierarchical Structure ◽  
Ethylenediaminetetraacetic Acid ◽  
Disodium Salt ◽  
Hollow Microspheres ◽  
Photoluminescence Properties ◽  
Controlled Preparation

Herein, calcium carbonate hollow microspheres with a micro–nano hierarchical structure were successfully synthesized using disodium salt of ethylenediaminetetraacetic acid (EDTA-2Na) as an additive, by bubbling pressurized carbon dioxide and calcium hydroxide at 120 °C.

The entry of acidic amino acids into brain and CSF during development, using in situ perfusion in the rat

1995 ◽  
Vol 90 (1-2) ◽  
pp. 151-158 ◽  
Author(s):  
Hameed Al-Sarraf ◽  
Jane E. Preston ◽  
Malcolm B. Segal
Keyword(s):  
Amino Acids ◽  
In Situ Perfusion ◽  
Acidic Amino Acids

scholarly journals CALCIUM SALTS OF AMINO ACIDS FOR THE TREATMENT OF OSTEOPOROSIS IN ANIMALS

2018 ◽  
Vol 54 (3) ◽  
pp. 314-318
Author(s):  
D. V. Lopatik ◽  
U. D. Kovalenko ◽  
Z. I. Kuvaeva ◽  
E. A. Manchik
Keyword(s):  
Amino Acids ◽  
Calcium Carbonate ◽  
Bone Tissue ◽  
Therapeutic Effect ◽  
Test Substance ◽  
Calcium Salts ◽  
Treatment Of Osteoporosis ◽  
Prevention And Treatment ◽  
Regeneration Of Bone Tissue ◽  
Regeneration Of Bone

Results of the study of the drug from calcium salts of amino acids (calcium diglycinate, calcium di-L-prolinate) on the model of osteoporosis in animals are described. The test substance was found to have better therapeutic effect in the regeneration of bone tissue in comparison with the drug containing calcium carbonate. The drug containing calcium salts of glycine and L-proline can be used for prevention and treatment of osteoporosis.

scholarly journals Extensive mutagenesis of a transcriptional activation domain identifies single hydrophobic and acidic amino acids important for activation in vivo.

1997 ◽  
Vol 17 (1) ◽  
pp. 115-122 ◽  
Author(s):  
M B Sainz ◽  
S A Goff ◽  
V L Chandler
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transcriptional Activation ◽  
Carboxyl Terminus ◽  
Wild Type ◽  
Activation Domain ◽  
Hydrophobic Residues ◽  
Transcriptional Activation Domain ◽  
Acidic Amino Acids

C1 is a transcriptional activator of genes encoding biosynthetic enzymes of the maize anthocyanin pigment pathway. C1 has an amino terminus homologous to Myb DNA-binding domains and an acidic carboxyl terminus that is a transcriptional activation domain in maize and yeast cells. To identify amino acids critical for transcriptional activation, an extensive random mutagenesis of the C1 carboxyl terminus was done. The C1 activation domain is remarkably tolerant of amino acid substitutions, as changes at 34 residues had little or no effect on transcriptional activity. These changes include introduction of helix-incompatible amino acids throughout the C1 activation domain and alteration of most single acidic amino acids, suggesting that a previously postulated amphipathic alpha-helix is not required for activation. Substitutions at two positions revealed amino acids important for transcriptional activation. Replacement of leucine 253 with a proline or glutamine resulted in approximately 10% of wild-type transcriptional activation. Leucine 253 is in a region of C1 in which several hydrophobic residues align with residues important for transcriptional activation by the herpes simplex virus VP16 protein. However, changes at all other hydrophobic residues in C1 indicate that none are critical for C1 transcriptional activation. The other important amino acid in C1 is aspartate 262, as a change to valine resulted in only 24% of wild-type transcriptional activation. Comparison of our C1 results with those from VP16 reveal substantial differences in which amino acids are required for transcriptional activation in vivo by these two acidic activation domains.

scholarly journals Effects of amino acids on conversion of calcium carbonate to hydroxyapatite

RSC Advances ◽  
2020 ◽  
Vol 10 (61) ◽  
pp. 37005-37013
Author(s):  
Sun Yanyan ◽  
Wang Guangxin ◽  
Sun Guoqing ◽  
Wang Yaming ◽  
Li Wuhui ◽  
...  
Keyword(s):  
Amino Acids ◽  
Calcium Carbonate

Conversion of calcium carbonate (calcite; CC) to hydroxyapatite (HAp) was examined when the CC particles of sub μm size were soaked at 37 °C for up to 10 d in 0.15 M K2HPO4 (20 ml), whose pH was set to 3–12.

Amino acid transport by juxtamedullary nephrons: distal reabsorption and recycling

1988 ◽  
Vol 255 (3) ◽  
pp. F397-F407 ◽  
Author(s):  
W. H. Dantzler ◽  
S. Silbernagl
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Acid Transport ◽  
Acidic Amino Acids ◽  
Vasa Recta ◽  
Collecting Ducts ◽  
Distal Site

Amino acid transport by juxtamedullary (JM) nephrons and its relationship to transport by superficial cortical (SC) nephrons and to function of vasa recta and collecting ducts were examined in vivo and in situ by free-flow micropuncture of Henle's loops, collecting ducts, and vasa recta and by continuous microinfusion of Henle's loops in exposed rat papillae. Fractional deliveries (FDs) of six neutral amino acids, two acidic amino acids, and taurine to tips of Henle's loops of JM nephrons could be substantially below those to early distal loops of SC nephrons, indicating that reabsorption before loop tips could be greater in JM than in SC nephrons. FDs to collecting ducts lower than to JM loop tips suggested reabsorption distal to loop tips. This was confirmed by continuous microinfusion of ascending limbs of Henle's loops. Distal site of reabsorption is unknown, but amino acids may move passively out of the thin ascending limb and be recycled into vasa recta and descending limb. Recycling of amino acids was supported by high FDs to tips of Henle's loops (sometimes greater than 1.0), higher concentrations in ascending than in descending vasa recta at same papilla level, and high mean concentrations in vasa recta.

Uptake and asymmetric efflux of amino acids at maternal and fetal sides of placenta

1981 ◽  
Vol 241 (3) ◽  
pp. C106-C112 ◽  
Author(s):  
B. M. Eaton ◽  
D. L. Yudilevich
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Guinea Pig ◽  
Cellular Uptake ◽  
Transport Systems ◽  
Acid Transport ◽  
Dilution Technique ◽  
Acidic Amino Acids ◽  
Tracer Dilution ◽  
Paired Tracer Dilution

Unidirectional uptake of eighteen amino acids into the syncytiotrophoblast was measured from both the maternal and fetal circulations of isolated dually perfused guinea pig placentas using a single-circulation, paired-tracer dilution technique. A bolus containing a tritiated amino acid and L-[14C]glucose (extracellular marker) was injected intra-arterially into one circulation, and both venous outflows were sequentially sampled. The maximal cellular uptake (Umax) on the injection side was determined from (1-[3H]/[14C]) values and used to calculate the unidirectional influx. Umax values for neutral and basic amino acids ranged between 15 and 58% and were similar on both sides of the trophoblast. Uptake of the acidic amino acids and taurine was minimal. Amino acid influx from either circulation was followed by rapid tracer backflux and transplacental transfer. Tracer efflux was asymmetric and preferentially directed towards the fetal side. It is suggested that amino acid transport systems are present on both surfaces of the placenta and that net transfer from mother to fetus is the result of asymmetric efflux from the trophoblast.

scholarly journals Structural factors influencing the reaction rates of 4-aryloxy-7-nitrobenzofurazans with amino acids

2004 ◽  
Vol 2 (4) ◽  
pp. 672-685 ◽  
Author(s):  
Marioara Bem ◽  
Marilena Vasilescu ◽  
Miron Caproiu ◽  
Constantin Draghici ◽  
Adrian Beteringhe ◽  
...  
Keyword(s):  
Amino Acids ◽  
Room Temperature ◽  
Reaction Rates ◽  
Structural Factors ◽  
Basic Amino Acids ◽  
Interesting Observation ◽  
Neutral Amino Acids ◽  
Acidic Amino Acids ◽  
Factors Influencing ◽  
Snar Reaction

AbstractAn interesting observation was made when studying the SNAr reaction between several 4-aryloxy-7-nitrobenzofurazans (2) and several amino acids leading to the apparition of detectable fluorescence from the substitution products3. Acidic amino acids reacted very slowly=while basic amino acids react fastest with2 having an unsubstituted phenyl or a 4-formyl-phenyl Ar group. Amongst neutral amino acids, proline reacts fastest at room temperature after 100 min. With2 having a methoxy-subtituted Ar group.

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