Abrupt aggregation of misfolded proteins is the underlying molecular cause of numerous severe pathologies including Alzheimer's and Parkinson's diseases.Protein aggregation yields small oligomers that can later propagate into amyloid fibrils, β-sheet-rich structures with a variety of topologies. A growing body of evidence suggests that lipids play an important role in abrupt aggregation of misfolded proteins. In this study, we investigate the roles of length and saturation of fatty acids (FAs) in phosphatidylserine (PS), an anionic lipid that is responsible for the recognition of apoptotic cells by macrophages, in lysozyme aggregation. We found that both the length and saturation of FAs in PS contribute to the aggregation rate of insulin. PS with 14-carbon-long FAs (14:0) enabled a much stronger acceleration of protein aggregation compared to PS with 18-carbon-long FAs (18:0). Our results demonstrate that the presence of double bonds in FAs accelerated the rate of insulin aggregation relative to PS with fully saturated FAs. Biophysical methods revealed morphological and structural differences in lysozyme aggregates grown in the presence of PS with varying lengths and FA saturation. We also found that such aggregates exerted diverse cell toxicities. These results demonstrate that the length and saturation of FAs in PS can uniquely alter the stability of misfolded proteins on lipid membranes.

Long-chain unsaturated and polyunsaturated fatty acids (LCUFAs and LCPUFAs, respectively) are the essential components of phospholipids and sphingolipids, major building blocks of plasma and organelle membranes. These molecules are also involved in cell signaling and energy metabolism. Hence, both LCUFAs and LCPUFAs are broadly used as food supplements. However, the role of these fatty acids (FAs) in the self-assembly of misfolded proteins remains unclear. In this study, we investigated the effect of LCUFAs and LCPUFAs, as well as their saturated analogue, on insulin aggregation. Using vibrational circular dichroism, we found that all analyzed FAs reversed the supramolecular chirality of insulin fibrils. Molecular dynamics simulations showed that strong hydrophobic interactions were formed between the long aliphatic tails of FAs and hydrophobic amino acid residues of insulin. We infer that such insulin:FA complexes had different self-assembly mechanisms compared to that of insulin alone, which resulted in the observed reversal of the supramolecular chirality of the amyloid fibrils.

Food security is an emerging problem that is faced by our civilization. There are millions of people around the world suffering from various kinds of malnutrition. The number of people that starve will only increase considering the continuous growth of the world’s population. The problem of food security can be addressed by timely detection and identification biotic and abiotic stresses in plants that drastically reduce the crop yield. A growing body of evidence suggests that Raman spectroscopy (RS), an emerging analytical technique, can be used for the confirmatory and non-invasive diagnostics of plant stresses. However, it remains unclear whether RS can efficiently disentangle biotic and abiotic stresses, as well as detect both of them simultaneously in plants. In this work, we modeled a stalk rot disease in corn by inoculating the plant stalks with Colletotrichum graminicola. In parallel, we subjected plants to salt stress, as well as challenging plants with both stalk rot disease and salinity stress simultaneously. After the stresses were introduced, Raman spectra were collected from the stalks to reveal stress-specific changes in the plant biochemistry. We found that RS was able to differentiate between stalk rot disease and salinity stresses with 100% accuracy, as well as predict presence of both of those stresses in plants on early and late stages. These results demonstrate that RS is a robust and reliable approach that can be used for confirmatory, non-destructive and label-free diagnostics of biotic and abiotic stresses in plants.

During bloating and active decay, human remains begin to deform and warp their physical identity. After the skin and muscles loosen and detach from their skeletal structuration, everything but bones, teeth, and hair will fully disintegrate into the soil that surrounds the body. Nearly half of people in the world dye their hair with a variety of permanent and semi-permanent colorants. Expanding upon this, we hypothesized that confirmatory analysis of hair colorants can be used to facilitate and advance forensic analysis of human remains. A growing body of evidence suggests that hair colorants can be identified directly on hair using surface-enhanced Raman spectroscopy (SERS). In this study, we investigate the extent to which SERS can be used to detect black and blue permanent and semi-permanent dyes on hair exposed to sunlight. Our results showed that although substantial photodegradation of all dyes was observed by week 7, SERS enabled highly accurate detection and identification of hair colorants during all 10 weeks of hair exposure to the sunlight with on average 99.2% accuracy. We also found that SERS could be used to predict fading rates of hair colorants. This information can shed light on the exposure of human remains to the exterior environment.

Difficulties in the localization of bodies of homicidal or drowning victims in natural water result in their submergence for weeks if not months. Water insects and microbes drastically change the body's appearance, which significantly changes the determination of a victim's identity. DNA analysis is commonly used for identifying the decedent; however, this PCR‐based approach is time‐consuming and destructive of the evidence. Considering that nearly half of the people in the world dye their hair with a variety of permanent and semi‐permanent dyes, one can expect that confirmatory identification of dyes on the body's hair can be used to shed light on the victim's identity. A growing body of evidence suggests that surface‐enhanced Raman spectroscopy (SERS) can be used to detect and identify hair dyes. In this study, we investigated the extent to which SERS could be used to detect black and blue, permanent and semi‐permanent dyes on hair submerged in hypolimnion water for up to twelve weeks. We found that SERS enabled 100% accurate identification of analyzed dyes on hair submerged in hypolimnion water for up to 8 weeks, whereas, on average, 87% accurate identification of the hair dyes could be achieved on hair exposed for 10 weeks and 50% for hair exposed 12 weeks in hypolimnion water. We also found that the aqueous environment caused progressive fading of some dyes, whereas other dyes showed substantial spectral transformations after prolonged submergence. Finally, we found that changes in the intensity of vibrational bands of dyes could be used to predict the duration of submergence of colored hair in hypolimnion water.