We have used the pH-induced self-assembly of a peptide-amphiphile to make a nanostructured fibrous scaffold reminiscent of extracellular matrix. The design of this peptide-amphiphile allows the nanofibers to be reversibly cross-linked to enhance or decrease their structural integrity. After cross-linking, the fibers are able to direct mineralization of hydroxyapatite to form a composite material in which the crystallographic c axes of hydroxyapatite are aligned with the long axes of the fibers. This alignment is the same as that observed between collagen fibrils and hydroxyapatite crystals in bone.

http://science.sciencemag.org/content/sci/294/5547/1684.full.pdf

Self-assembly and mineralization of peptide-amphiphile nanofibers

Raman spectra of biological materials are very complex, because they consist of signals from all molecules present in cells. In order to obtain chemical information from these spectra, it is necessary to know the Raman patterns of the possible components of a cell. In this paper, we present a collection of Raman spectra of biomolecules that can serve as references for the interpretation of Raman spectra of biological materials. We included the most important components present in a cell: (1) DNA and RNA bases (adenine, cytosine, guanine, thymine and uracil), (2) amino acids (glycine, L-alanine, L-valine, L-serine, L-glutamic acid, L-arginine, L-phenylalanine, L-tyrosine, L-tryptophan, L-histidine, L-proline), (3) fatty acids and fats (lauric acid, myristic acid, palmitic acid, stearic acid, 12-methyltetradecanoic acid, 13-methylmyristic acid, 14-methylpentadecanoic acid, 14-methylhexadecanoic acid, 15-methylpalmitic acid, oleic acid, vaccenic acid, glycerol, triolein, trilinolein, trilinolenin), (4) saccharides (β-D-glucose, lactose, cellulose, D-(+)-dextrose, D-(+)-trehalose, amylose, amylopectine, D-(+)-mannose, D-(+)-fucose, D-(−)-arabinose, D-(+)-xylose, D-(−)-fructose, D-(+)-galactosamine, N-acetyl-D-glucosamine, chitin), (5) primary metabolites (citric acid, succinic acid, fumarate, malic acid, pyruvate, phosphoenolpyruvate, coenzyme A, acetyl coenzyme A, acetoacetate, D-fructose-6-phosphate) and (6) others (β-carotene, ascorbic acid, riboflavin, glutathione). Examples of Raman spectra of bacteria and fungal spores are shown, together with band assignments to the reference products. Copyright © 2007 John Wiley & Sons, Ltd.

Reference database of Raman spectra of biological molecules

The biological effects and expected fate of the vast amount of oil in the Gulf of Mexico from the Deepwater Horizon blowout are unknown owing to the depth and magnitude of this event. Here, we report that the dispersed hydrocarbon plume stimulated deep-sea indigenous γ-Proteobacteria that are closely related to known petroleum degraders. Hydrocarbon-degrading genes coincided with the concentration of various oil contaminants. Changes in hydrocarbon composition with distance from the source and incubation experiments with environmental isolates demonstrated faster-than-expected hydrocarbon biodegradation rates at 5°C. Based on these results, the potential exists for intrinsic bioremediation of the oil plume in the deep-water column without substantial oxygen drawdown.

/pdf/deep-sea-oil-plume-enriches-indigenous-oil-degrading-2g4thhe93i.pdf

Deep-sea oil plume enriches indigenous oil-degrading bacteria.

Starch retrogradation is a process in which disaggregated amylose and amylopectin chains in a gelatinized starch paste reassociate to form more ordered structures. Starch retrogradation has been the subject of intensive research over the last 50 years, mainly due to its detrimental effect on the sensory and storage qualities of many starchy foods. However, starch retrogadation is desirable for some starchy food products in terms of textural and nutritional properties. To better understand the effect of starch retrogradation on the quality of starchy foods, measurement methods of starch retrogradation and factors that influence starch retrogradation have been studied extensively. This article provides a comprehensive review of starch retrogradation including the definition of the process, molecular mechanisms of how it occurs, and measurement methods and factors that influence starch retrogradation. The review also discusses the effect of retrogradation on the in vitro enzyme digestibility of starch. Spectroscopic methods such as FTIR and Raman are considered to be very promising in characterizing starch retrogradation at a molecular level, although more studies are needed in the future.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12143

Starch retrogradation: a comprehensive review

Cellulose nanowhiskers from coconut husk fibers: Effect of preparation conditions on their thermal and morphological behavior

The third edition of this highly successful manual is not only a revised text but has been extended to meet the interpretive needs of Raman users as well as those working in the IR region. The result is a uniquely practical, comprehensive and detailed source for spectral interpretation. Combining in one volume, the correlation charts and tables for spectral interpretation for these two complementary techniques, this book will be of great benefit to those using or considering either technique.In addition to the new Raman coverage the new edition offers:* new section on macromolecules including synthetic polymers and biomolecules;* expansion of the section on NIR (near infrared region) to reflect recent growth in this area;* extended chapter on inorganic compounds including minerals and glasses;* redrawn and updated charts plus a number of new charts covering data new to this edition.This new edition will be invaluable in every industrial, university, government and hospital laboratory where infrared (FT-IR) and Raman spectral data need to be analysed.

George Socrates

Papers

Infrared and Raman Characteristic Group Frequencies: Tables and Charts