scholarly journals Spontaneous emergence of membrane-forming protoamphiphiles from a lipid-amino acid mixture under wet-dry cycles

2021 ◽  
Author(s):  
Manesh Prakash Joshi ◽  
Anupam A Sawant ◽  
Sudha Rajamani
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Membrane Assembly ◽  
Prebiotic Earth ◽  
Dynamic Interplay

Dynamic interplay between peptide synthesis and membrane assembly would have been crucial for the emergence of protocells on the prebiotic Earth. However, the effect of membrane-forming amphiphiles on peptide synthesis,...

scholarly journals Spontaneous Emergence of Membrane-Forming Protoamphiphiles from a Lipid-Amino Acid Mixture Under Wet-Dry Cycles

2020 ◽  
Author(s):  
Manesh Joshi ◽  
Anupam Sawant ◽  
Sudha Rajamani
Keyword(s):  
Fatty Acids ◽  
Amino Acid ◽  
Peptide Synthesis ◽  
Exchange Process ◽  
Chemical Species ◽  
Selective Advantage ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Complex Interactions ◽  
Life On Earth

<p>The prelude to the origin of cellular life on Earth would have involved a fundamental step, that of protocell formation. This involves the coming together of two crucial processes; abiotic synthesis of informational and catalytic polymers, and the assembly of membrane compartments. Mutual interactions between these processes would have likely affected the emergence and early stages of protocell evolution. Previous investigations have predominantly focused on cooperative interactions, often neglecting any competitive behavior that might ensue as ‘counterproductive cross-talk’. However, in a realistic scenario, both cooperative and competitive reactions would have occurred simultaneously in a complex prebiotic soup, generating a plethora of chemical species with their own prebiotic implications. In this study, we followed a systematic and unbiased approach to explore this interdependence. We used a lipid-amino acid system to demonstrate the above-mentioned phenomenon wherein we investigated the effect of a membrane-forming amphiphile on peptide synthesis, under prebiotically plausible conditions. </p><p><br></p> <p>Interestingly, our study shows the formation of a hitherto unobserved reaction product that could have played a significant role during the emergence of life on the early Earth. We do show that peptide synthesis occurs but with a decrease in the yield. This is due to another concurrent and competing reaction, wherein an amino acid covalently interacts with a phospholipid to generate new amphiphilic species called N-acyl amino acids (NAAs) via an ester-amide exchange process. These NAAs are thermostable and, hence, persistent even at high temperatures. Furthermore, this protoamphiphile is also able to self-assemble into vesicles at acidic pH. <i>Au contraire</i>, fatty acids, a widely accepted constituent of prebiotic compartments, have been shown to generate vesicles only at neutral to alkaline pH. Thus, NAAs could have had a selective advantage over fatty acids to form thermostable protocell compartments under acidic geothermal pool-like conditions, a niche that has gained prominence as one of the important geological settings where life could have originated. Our study underlines the importance of an unbiased exploration of the complex interactions between prebiotic processes, which could potentially open new avenues to solving the origin of life conundrum. </p> <p> </p>

scholarly journals Spontaneous Emergence of Membrane-Forming Protoamphiphiles from a Lipid-Amino Acid Mixture Under Wet-Dry Cycles

2020 ◽  
Author(s):  
Manesh Joshi ◽  
Anupam Sawant ◽  
Sudha Rajamani
Keyword(s):  
Fatty Acids ◽  
Amino Acid ◽  
Peptide Synthesis ◽  
Exchange Process ◽  
Chemical Species ◽  
Selective Advantage ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Complex Interactions ◽  
Life On Earth

<p>The prelude to the origin of cellular life on Earth would have involved a fundamental step, that of protocell formation. This involves the coming together of two crucial processes; abiotic synthesis of informational and catalytic polymers, and the assembly of membrane compartments. Mutual interactions between these processes would have likely affected the emergence and early stages of protocell evolution. Previous investigations have predominantly focused on cooperative interactions, often neglecting any competitive behavior that might ensue as ‘counterproductive cross-talk’. However, in a realistic scenario, both cooperative and competitive reactions would have occurred simultaneously in a complex prebiotic soup, generating a plethora of chemical species with their own prebiotic implications. In this study, we followed a systematic and unbiased approach to explore this interdependence. We used a lipid-amino acid system to demonstrate the above-mentioned phenomenon wherein we investigated the effect of a membrane-forming amphiphile on peptide synthesis, under prebiotically plausible conditions. </p><p><br></p> <p>Interestingly, our study shows the formation of a hitherto unobserved reaction product that could have played a significant role during the emergence of life on the early Earth. We do show that peptide synthesis occurs but with a decrease in the yield. This is due to another concurrent and competing reaction, wherein an amino acid covalently interacts with a phospholipid to generate new amphiphilic species called N-acyl amino acids (NAAs) via an ester-amide exchange process. These NAAs are thermostable and, hence, persistent even at high temperatures. Furthermore, this protoamphiphile is also able to self-assemble into vesicles at acidic pH. <i>Au contraire</i>, fatty acids, a widely accepted constituent of prebiotic compartments, have been shown to generate vesicles only at neutral to alkaline pH. Thus, NAAs could have had a selective advantage over fatty acids to form thermostable protocell compartments under acidic geothermal pool-like conditions, a niche that has gained prominence as one of the important geological settings where life could have originated. Our study underlines the importance of an unbiased exploration of the complex interactions between prebiotic processes, which could potentially open new avenues to solving the origin of life conundrum. </p> <p> </p>

An open-label, single-center pilot study to test the effects of an amino acid mixture in older patients admitted to internal medicine wards

Nutrition ◽  
2020 ◽  
Vol 69 ◽  
pp. 110588 ◽  
Author(s):  
Francesco Bellanti ◽  
Aurelio Lo Buglio ◽  
Elena Di Stasio ◽  
Giorgia di Bello ◽  
Rosanna Tamborra ◽  
...  
Keyword(s):  
Internal Medicine ◽  
Amino Acid ◽  
Pilot Study ◽  
Older Patients ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Single Center ◽  
Open Label ◽  
Internal Medicine Wards

Choosing A Balanced Amino Acid Mixture

1970 ◽  
Vol 100 (3) ◽  
pp. 380-380 ◽  
Author(s):  
Hans Fisher
Keyword(s):  
Amino Acid ◽  
Amino Acid Mixture ◽  
Acid Mixture

scholarly journals Effect of co-ingestion of amino acids with rice on glycaemic and insulinaemic response

2015 ◽  
Vol 114 (11) ◽  
pp. 1845-1851 ◽  
Author(s):  
Yean Yean Soong ◽  
Joseph Lim ◽  
Lijuan Sun ◽  
Christiani Jeyakumar Henry
Keyword(s):  
Amino Acids ◽  
Blood Glucose ◽  
Amino Acid ◽  
Glycaemic Index ◽  
Amino Acid Mixture ◽  
Postprandial Blood Glucose ◽  
Acid Mixture ◽  
White Rice ◽  
Amino Acid Mixtures

AbstractConsumption of high glycaemic index (GI) and glycaemic response (GR) food such as white rice has been implicated in the development of type 2 diabetes. Previous studies have reported the ability of individual amino acids to reduce GR of carbohydrate-rich foods. Because of the bitter flavour of amino acids, they have rarely been used to reduce GR. We now report the use of a palatable, preformed amino acid mixture in the form of essence of chicken. In all, sixteen healthy male Chinese were served 68 or 136 ml amino acid mixture together with rice, or 15 or 30 min before consumption of white rice. Postprandial blood glucose and plasma insulin concentrations were measured at fasting and every 15 min after consumption of the meal until 60 min after the consumption of the white rice. Subsequent blood samples were taken at 30-min intervals until 210 min. The co-ingestion of 68 ml of amino acid mixture with white rice produced the best results in reducing the peak blood glucose and GR of white rice without increasing the insulinaemic response. It is postulated that amino acid mixtures prime β-cell insulin secretion and peripheral tissue uptake of glucose. The use of ready-to-drink amino acid mixtures may be a useful strategy for lowering the high-GI rice diets consumed in Asia.

Olfactory Conditioning by Association with Histidine-Free or Balanced Amino Acid Loads in Rats†

1973 ◽  
Vol 25 (3) ◽  
pp. 354-359 ◽  
Author(s):  
P. C. Simson ◽  
D. A. Booth
Keyword(s):  
Amino Acid ◽  
Food Intake ◽  
Amino Acid Mixture ◽  
Conditioned Aversion ◽  
Acid Mixture ◽  
Olfactory Conditioning ◽  
Conditioned Preference ◽  
Gastric Intubation ◽  
Protein Free Diet

An histidine-devoid but otherwise balanced amino acid mixture depressed food intake from 2 hr after its gastric intubation. It induced conditioned aversion to an odour incorporated in a protein-free diet presented for 6 h following intubation. In other rats, a balanced amino acid mixture established conditioned preference for odour presented in the same diet for 6 h following intubation. The degree of preference was considerably less than the degree of aversion.

Liver extract and its free amino acids equally stimulate gastric acid secretion

1980 ◽  
Vol 239 (6) ◽  
pp. G493-G496 ◽  
Author(s):  
E. J. Feldman ◽  
M. I. Grossman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Free Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Liver Extract ◽  
Amino Acid Mixture ◽  
Acid Mixture

Using intragastric titration in dogs with gastric fistulas, dose-response studies were carried out with liver extract and with a mixture of amino acids that matched the free amino acids found in liver extract. All solutions were adjusted to pH 7.0 and osmolality to 290 mosmol x kg-1. Doses are expressed as the sum of the concentrations of all free amino acids. At each dose studied (free amino acid concentration: 2.8, 5.6, 11, 23, and 45 mM), acid secretion in response to the free amino acid mixture was not significantly different from that of liver extract. The peak response to both liver extract and the free amino acid mixture occurred with the 23-mM dose and represented about 60% of the maximal response to histamine. The serum concentrations of gastrin after liver extract and the amino acid mixture were not significantly different. It is concluded that in dogs with gastric fistula, gastric acid secretion and release of gastrin were not significantly different in response to liver extract and to a mixture of amino acids that simulated the free amino acid content of liver extract.

Sign in / Sign up

Export Citation Format

Share Document