Absorption of L-alanine and other dissolved nutrients by the spines of Paracentrotus lividus (Echinoidea)

1977 ◽  
Vol 57 (4) ◽  
pp. 1031-1045 ◽  
Author(s):  
M. E. de Burgh ◽  
A. B. West ◽  
F. Jeal
Keyword(s):  
Amino Acids ◽  
Organic Molecules ◽  
Marine Invertebrates ◽  
Analytical Techniques ◽  
Paracentrotus Lividus ◽  
Direct Absorption ◽  
Dissolved Nutrients ◽  
Recent Developments ◽  
Modern Analytical

The possibility that marine invertebrates might obtain part of their nutritional requirements by direct absorption of dissolved molecules through the epidermis has recently received considerable attention. This revival of interest in a field which had been virtually abandoned since the early part of the century was led by the findings of Stephens & Schinske (1957, 1958, 1961). Modern analytical techniques have revealed that the amount of dissolved nutrients in coastal waters is much greater than was formerly realized; total amino acids have been recorded in concentrations of up to 10-4 mole/litre in south-east Alaskan waters (Schell, 1974) and 7 x 10-5 mole/litre off Helgoland (Bohling, 1970). Direct absorption of amino acids has been conclusively established in several phyla (see reviews by Stephens, 1968,1972), and one of the major aims of current research is to show that dissolved organic molecules taken up from available concentrations could be of nutritional significance. Recent developments concerning the possible roles of uptake in marine ecosystems have been reviewed by West, de Burgh & Jeal (1977).

scholarly journals d-Amino Acids and Lactic Acid Bacteria

2019 ◽  
Vol 7 (12) ◽  
pp. 690 ◽  
Author(s):  
Jyumpei Kobayashi
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Analytical Techniques ◽  
Fermented Foods ◽  
Metabolizing Enzymes ◽  
Recent Developments ◽  
Living Organisms ◽  
And Function ◽  
Asymmetric Carbon

Proteins are composed of l-amino acids except for glycine, which bears no asymmetric carbon atom. Accordingly, researchers have studied the function and metabolism of l-amino acids in living organisms but have paid less attention to the presence and roles of their d-enantiomers. However, with the recent developments in analytical techniques, the presence of various d-amino acids in the cells of various organisms and the importance of their roles have been revealed. For example, d-serine (d-Ser) and d-aspartate (d-Asp) act as neurotransmitters and hormone-like substances, respectively, in humans, whereas some kinds of d-amino acids act as a biofilm disassembly factor in bacteria. Interestingly, lactic acid bacteria produce various kinds of d-amino acids during fermentation, and many d-amino acids taste sweet, compared with the corresponding l-enantiomers. The influence of d-amino acids on human health and beauty has been reported in recent years. These facts suggest that the d-amino acids produced by lactic acid bacteria are important in terms of the taste and function of lactic-acid-fermented foods. Against this background, unique d-amino-acid-metabolizing enzymes have been searched for and observed in lactic acid bacteria. This review summarizes and introduces the importance of various d-amino acids in this regard.

Specificity of L-Alanine Transport in the Spine Epithelium of Paracentrotus Lividus (Echinoidea)

1978 ◽  
Vol 58 (2) ◽  
pp. 425-440 ◽  
Author(s):  
M. E. de Burgh
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Active Transport ◽  
Marine Invertebrates ◽  
Paracentrotus Lividus ◽  
Arenicola Marina ◽  
Nereis Virens ◽  
Alanine Transport ◽  
Active Transport System ◽  
Digestive Glands

In many marine invertebrates the presence of an active transport system for the epithelial absorption of amino acids has been conclusively demonstrated (Stephens, 1968. 1972; West, de Burgh & Jeal, 1977). It has been observed by several authors that inhibition of uptake of a given amino acid can occur in the presence of other amino acids, in a manner analogous to that observed in vertebrate gut absorption systems. Some examples are the work of Chapman & Taylor (1969) on whole Nereis virens, Ferguson (1968) on the digestive glands of Echinaster spinulosus, Ferguson (1971) on whole asteroids, Bamford & Stewart (1973 a, b) on Arenicola marina gut, and Bamford & McCrea (1975) on the gill of Cerastoderma edule.

Recent Developments in CE-MS Based Metabolomics

2020 ◽  
Vol 16 ◽  
Author(s):  
Mustafa Çelebier ◽  
Merve Nenni
Keyword(s):  
Sample Preparation ◽  
Scientific Information ◽  
Analytical Techniques ◽  
Living Organism ◽  
Analytical Technique ◽  
Ionic Compounds ◽  
Recent Sample ◽  
Recent Developments ◽  
Endogenous Metabolites ◽  
Preparation Techniques

Background: Metabolomics has gained importance in clinical applications over the last decade. Metabolomics studies are significant because the systemic metabolome is directly affected by disease conditions. Metabolome-based biomarkers are actively being developed for early diagnosis and to indicate the stage of specific diseases. Additionally, understanding the effect of an intervention on a living organism at the molecular level is a crucial strategy for understanding novel or unexpected biological processes. Results: The simultaneous improvements in advanced analytical techniques, sample preparation techniques, computer technology, and databank contents has enabled more valuable scientific information to be gained from metabolomics than ever before. With over 15,000 known endogenous metabolites, there is no single analytical technique capable of analyzing the whole metabolome. However, capillary electrophoresis-mass spectrometry (CE-MS) is a unique technique used to analyze an important portion of metabolites not accessible by liquid chromatography or gas chromatography techniques. The analytical capability of CE, combined with recent sample preparation techniques focused on extracting polar-ionic compounds, make CE-MS a perfect technique for metabolomic studies. Conclusion: Here, previous reviews of CE-MS based metabolomics are evaluated to highlight recent improvements in this technique. Specifically, we review papers from the last two years (2018 and 2019) on CE-MS based metabolomics. The current situation and the challenges facing metabolomic studies are discussed to reveal the high potential of CE-MS for further studies, especially in biomarker development studies.

scholarly journals Effects of Glyphosate-Based and Derived Products on Sea Urchin Larval Development

2020 ◽  
Vol 8 (9) ◽  
pp. 661
Author(s):  
Davide Asnicar ◽  
Costanza Cappelli ◽  
Ahmad Safuan Sallehuddin ◽  
Nur Atiqah Maznan ◽  
Maria Gabriella Marin
Keyword(s):  
Larval Development ◽  
Sea Urchin ◽  
Marine Invertebrates ◽  
Parent Compound ◽  
Paracentrotus Lividus ◽  
Marine Species ◽  
Negative Effects ◽  
Aminomethylphosphonic Acid ◽  
Main Degradation Product ◽  
Herbicide Glyphosate

Despite the widespread use of herbicide glyphosate in cultivation, its extensive runoff into rivers and to coastal areas, and the persistence of this chemical and its main degradation product (aminomethylphosphonic acid, AMPA) in the environment, there is still little information on the potential negative effects of glyphosate, its commercial formulation Roundup® and AMPA on marine species. This study was conducted with the aim of providing a comparative evaluation of the effects of glyphosate-based and its derived chemicals on the larval development of the sea urchin Paracentrotus lividus, thus providing new data to describe the potential ecotoxicity of these contaminants. In particular, the effects on larval development, growth and metabolism were assessed during 48 h of exposure from the time of egg fertilization. The results confirm that AMPA and its parent compound, glyphosate have similar toxicity, as observed in other marine invertebrates. However, interestingly, the Roundup® formulation seemed to be less toxic than the glyphosate alone.

scholarly journals Peculiarities of promiscuous l-threonine transaldolases for enantioselective synthesis of β-hydroxy-α-amino acids

2021 ◽  
Author(s):  
Shan Wang ◽  
Hai Deng
Keyword(s):  
Amino Acids ◽  
Organic Molecules ◽  
Stereoselective Synthesis ◽  
Enantioselective Synthesis ◽  
General Mechanism ◽  
Future Developments ◽  
Key Points ◽  
Biomaterial Science ◽  
One Step ◽  
Harsh Conditions

Abstract The introduction of β-hydroxy-α-amino acids (βHAAs) into organic molecules has received considerable attention as these molecules have often found widespread applications in bioorganic chemistry, medicinal chemistry and biomaterial science. Despite innovation of asymmetric synthesis of βHAAs, stereoselective synthesis to control the two chiral centres at Cα and Cβ positions is still challenging, with poor atomic economy and multi protection and deprotection steps. These syntheses are often operated under harsh conditions. Therefore, a biotransformation approach using biocatalysts is needed to selectively introduce these two chiral centres into structurally diverse molecules. Yet, there are few ways that enable one-step synthesis of βHAAs. One is to extend the substrate scope of the existing enzyme inventory. Threonine aldolases have been explored to produce βHAAs. However, the enzymes have poor controlled installation at Cβ position, often resulting in a mixture of diastereoisomers which are difficult to be separated. In this respect, l-threonine transaldolases (LTTAs) offer an excellent potential as the enzymes often provide controlled stereochemistry at Cα and Cβ positions. Another is to mine LTTA homologues and engineer the enzymes using directed evolution with the aim of finding engineered biocatalysts to accept broad substrates with enhanced conversion and stereoselectivity. Here, we review the development of LTTAs that incorporate various aldehyde acceptors to generate structurally diverse βHAAs and highlight areas for future developments. Key points • The general mechanism of the transaldolation reaction catalysed by LTTAs • Recent advances in LTTAs from different biosynthetic pathways • Applications of LTTAs as biocatalysts for production of βHAAs

scholarly journals Chiroptical activity of hydroxycarboxylic acids with implications for the origin of biological homochirality

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jana Bocková ◽  
Nykola C. Jones ◽  
Uwe J. Meierhenrich ◽  
Søren V. Hoffmann ◽  
Cornelia Meinert
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Organic Molecules ◽  
Building Blocks ◽  
Aliphatic Chain ◽  
Monocarboxylic Acids ◽  
Hydroxycarboxylic Acids ◽  
Polarised Light ◽  
Suitable Target ◽  
Anisotropy Spectra

AbstractCircularly polarised light (CPL) interacting with interstellar organic molecules might have imparted chiral bias and hence preluded prebiotic evolution of biomolecular homochirality. The l-enrichment of extra-terrestrial amino acids in meteorites, as opposed to no detectable excess in monocarboxylic acids and amines, has previously been attributed to their intrinsic interaction with stellar CPL revealed by substantial differences in their chiroptical signals. Recent analyses of meteoritic hydroxycarboxylic acids (HCAs) – potential co-building blocks of ancestral proto-peptides – indicated a chiral bias toward the l-enantiomer of lactic acid. Here we report on novel anisotropy spectra of several HCAs using a synchrotron radiation electronic circular dichroism spectrophotometer to support the re-evaluation of chiral biomarkers of extra-terrestrial origin in the context of absolute photochirogenesis. We found that irradiation by CPL which would yield l-excess in amino acids would also yield l-excess in aliphatic chain HCAs, including lactic acid and mandelic acid, in the examined conditions. Only tartaric acid would show “unnatural” d-enrichment, which makes it a suitable target compound for further assessing the relevance of the CPL scenario.

scholarly journals Determination of amino acids in human biological fluids by high-performance liquid chromatography: critical review

Amino Acids ◽  
2021 ◽  
Author(s):  
Grażyna Gałęzowska ◽  
Joanna Ratajczyk ◽  
Lidia Wolska
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
High Performance ◽  
Hplc Analysis ◽  
Limit Of Detection ◽  
Biological Fluids ◽  
Analytical Techniques ◽  
Epidemiological Studies ◽  
Preparation Conditions

AbstractThe quantitation and qualification of amino acids are most commonly used in clinical and epidemiological studies, and provide an excellent way of monitoring compounds in human fluids which have not been monitored previously, to prevent some diseases. Because of this, it is not surprising that scientific interest in evaluating these compounds has resurfaced in recent years and has precipitated the development of a multitude of new analytical techniques. This review considers recent developments in HPLC analytics on the basis of publications from the last few years. It helps to update and systematize knowledge in this area. Particular attention is paid to the progress of analytical methods, pointing out the advantages and drawbacks of the various techniques used for the preparation, separation and determination of amino acids. Depending on the type of sample, the preparation conditions for HPLC analysis change. For this reason, the review has focused on three types of samples, namely urine, blood and cerebrospinal fluid. Despite time-consuming sample preparation before HPLC analysis, an additional derivatization technique should be used, depending on the detection technique used. There are proposals for columns that are specially modified for amino acid separation without derivatization, but the limit of detection of the substance is less beneficial. In view of the fact that amino acid analyses have been performed for years and new solutions may generate increased costs, it may turn out that older proposals are much more advantageous.

scholarly journals Rethinking SME default prediction: a systematic literature review and future perspectives

2021 ◽  
Author(s):  
Francesco Ciampi ◽  
Alessandro Giannozzi ◽  
Giacomo Marzi ◽  
Edward I. Altman
Keyword(s):  
Literature Review ◽  
Systematic Literature Review ◽  
Global Financial Crisis ◽  
Analytical Techniques ◽  
Future Research ◽  
Finance Management ◽  
Default Prediction ◽  
Emerging Issues ◽  
Medium Enterprise ◽  
Modern Analytical

AbstractOver the last dozen years, the topic of small and medium enterprise (SME) default prediction has developed into a relevant research domain that has grown for important reasons exponentially across multiple disciplines, including finance, management, accounting, and statistics. Motivated by the enormous toll on SMEs caused by the 2007–2009 global financial crisis as well as the recent COVID-19 crisis and the consequent need to develop new SME default predictors, this paper provides a systematic literature review, based on a statistical, bibliometric analysis, of over 100 peer-reviewed articles published on SME default prediction modelling over a 34-year period, 1986 to 2019. We identified, analysed and reviewed five streams of research and suggest a set of future research avenues to help scholars and practitioners address the new challenges and emerging issues in a changing economic environment. The research agenda proposes some new innovative approaches to capture and exploit new data sources using modern analytical techniques, like artificial intelligence, machine learning, and macro-data inputs, with the aim of providing enhanced predictive results.

scholarly journals Recent Advances in Rapid Synthesis of Non-proteinogenic Amino Acids from Proteinogenic Amino Acids Derivatives via Direct Photo-Mediated C–H Functionalization

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5270
Author(s):  
Zhenbo Yuan ◽  
Xuanzhong Liu ◽  
Changmei Liu ◽  
Yan Zhang ◽  
Yijian Rao
Keyword(s):  
Amino Acids ◽  
Direct Synthesis ◽  
Environmentally Friendly ◽  
Powerful Method ◽  
Rapid Synthesis ◽  
Conservation Of Energy ◽  
Mild Conditions ◽  
Recent Advances ◽  
Recent Developments

Non-proteinogenic amino acids have attracted tremendous interest for their essential applications in the realm of biology and chemistry. Recently, rising C–H functionalization has been considered an alternative powerful method for the direct synthesis of non-proteinogenic amino acids. Meanwhile, photochemistry has become popular for its predominant advantages of mild conditions and conservation of energy. Therefore, C–H functionalization and photochemistry have been merged to synthesize diverse non-proteinogenic amino acids in a mild and environmentally friendly way. In this review, the recent developments in the photo-mediated C–H functionalization of proteinogenic amino acids derivatives for the rapid synthesis of versatile non-proteinogenic amino acids are presented. Moreover, postulated mechanisms are also described wherever needed.

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