This book is written as a reference on organic substances in natural waters and as a supplementary text for graduate students in water chemistry. The chapters address five topics: amount, origin, nature, geochemistry, and characterization of organic carbon. Of these topics, the main themes are the amount and nature of dissolved organic carbon in natural waters (mainly fresh water, although seawater is briefly discussed). It is hoped that the reader is familiar with organic chemistry, but it is not necessary. The first part of the book is a general overview of the amount and general nature of dissolved organic carbon. Over the past 10 years there has been an exponential increase in knowledge on organic substances in water, which is the result of money directed toward the research of organic compounds, of new methods of analysis (such as gas chromatography and mass spectrometry), and most importantly, the result of more people working in this field. Because of this exponential increase in knowledge, there is a need to pull together and summarize the data that has accumulated from many disciplines over the last decade.

Organic geochemistry of natural waters

DNA analogues are currently being intensely investigated owing to their potential as gene-targeted drugs. Furthermore, their properties and interaction with DNA and RNA could provide a better understanding of the structural features of natural DNA that determine its unique chemical, biological and genetic properties. We recently designed a DNA analogue, PNA, in which the backbone is structurally homomorphous with the deoxyribose backbone and consists of N-(2-aminoethyl)glycine units to which the nucleobases are attached. We showed that PNA oligomers containing solely thymine and cytosine can hybridize to complementary oligonucleotides, presumably by forming Watson-Crick-Hoogsteen (PNA)2-DNA triplexes, which are much more stable than the corresponding DNA-DNA duplexes, and bind to double-stranded DNA by strand displacement. We report here that PNA containing all four natural nucleobases hybridizes to complementary oligonucleotides obeying the Watson-Crick base-pairing rules, and thus is a true DNA mimic in terms of base-pair recognition.

PNA hybridizes to complementary oligonucleotides obeying the Watson–Crick hydrogen-bonding rules

Anesthesiology. First of two parts.

1. Light and Energy. 2. Organization and Structure of Photosynthetic Systems. 3. History and Development of Photosynthesis. 4. Photosynthetic Pigments-Structure and Spectroscopy. 5. Antenna Complexes and Energy Transfer Processes. 6. Reaction Center Complexes. 7. Electron Transfer Pathways and Components. 8. Chemiosmotic Coupling and ATP Synthesis. 9. Carbon Metabolism. 10. Genetics, Assembly and Regulation of Photosynthetic. Systems. 11. Origin and Evolution of Photosynthesis. Appendix 1. Light, Energy and Kinetics

Molecular mechanisms of photosynthesis

The development of new orthogonal aminoacyl-tRNA synthetase/tRNA pairs has led to the addition of approximately 70 unnatural amino acids (UAAs) to the genetic codes of Escherichia coli, yeast, and mammalian cells. These UAAs represent a wide range of structures and functions not found in the canonical 20 amino acids and thus provide new opportunities to generate proteins with enhanced or novel properties and probes of protein structure and function.

/pdf/adding-new-chemistries-to-the-genetic-code-1k393jaizr.pdf

Adding New Chemistries to the Genetic Code

atmosphere of methane, ammonia, water, and hydrogen instead of carbon dioxide, nitrogen, oxygen, and water was suggested by Oparin (1) and has been-given emphasis recently by Urey (2) and Bernal (3) In order to test this hypothesis, an apparatus was built to circulate CHI4, NH3, H2O, and H2 past an electric discharge The resulting mixture has been tested for amino acids by paper chromatography Electrical discharge was used to form free radicals instead of ultraviolet light, because quartz absorbs wavelengths short enough to cause photo-dissociation of the gases Electrical discharge may have played a significant role in the formation of compounds in the

/pdf/a-production-of-amino-acids-under-possible-primitive-earth-yv5oy6lsrq.pdf

A Production of Amino Acids Under Possible Primitive Earth Conditions

https://science.sciencemag.org/content/sci/130/3370/245.full.pdf

Organic Compound Synthesis on the Primitive Earth

Production of Some Organic Compounds under Possible Primitive Earth Conditions1

Hydrothermal vents jetting out water at 380° ± 30°C have been discovered on the axis of the East Pacific Rise. The hottest waters issue from mineralized chimneys and are blackened by sulfide precipitates. These hydrothermal springs are the sites of actively forming massive sulfide mineral deposits. Cooler springs are clear to milky and support exotic benthic communities of giant tube worms, clams, and crabs similar to those found at the Galapagos spreading center. Four prototype geophysical experiments were successfully conducted in and near the vent area: seismic refraction measurements with both source (thumper) and receivers on the sea floor, on-bottom gravity measurements, in situ magnetic gradiometer measurements from the submersible Alvin over a sea-floor magnetic reversal boundary, and an active electrical sounding experiment. These high-resolution determinations of crustal properties along the spreading center were made to gain knowledge of the source of new oceanic crust and marine magnetic anomalies, the nature of the axial magma chamber, and the depth of hydrothermal circulation.

https://science.sciencemag.org/content/sci/207/4438/1421.full.pdf

East Pacific Rise: Hot Springs and Geophysical Experiments

The idea that the first living systems on earth were based on self-replicating RNA molecules has recently become popular as a result of the discovery of ribozymes. However, there are several major problems associated with the prebiotic synthesis of ribonucleotides. In addition, there is the newly recognized problem of enantiomeric cross-inhibition, whereby template-directed polymerization involving one enantiomer of RNA is inhibited strongly by the presence of the other enantiomer. Here we propose that RNA was preceded in the evolution of life by a polymer constructed from flexible, acyclic, probably prochiral nucleotide analogues that were synthesized readily on the primitive earth. Several potentially prebiotic nucleotide analogues are considered in this context, and some of the consequences of this proposal are discussed.

https://www.pnas.org/content/pnas/84/13/4398.full.pdf

Stanley L. Miller

Papers

A Production of Amino Acids Under Possible Primitive Earth Conditions

Organic Compound Synthesis on the Primitive Earth

Production of Some Organic Compounds under Possible Primitive Earth Conditions1

East Pacific Rise: Hot Springs and Geophysical Experiments

The case for an ancestral genetic system involving simple analogues of the nucleotides.