Chemical Fingerprinting of Heat Stress Responses in the Leaves of Common Wheat by Fourier Transform Infrared Spectroscopy

Wheat (Triticum aestivum L.) is known to be negatively affected by heat stress, and its production is threatened by global warming, particularly in arid regions. Thus, efforts to better understand the molecular responses of wheat to heat stress are required. In the present study, Fourier transform infrared (FTIR) spectroscopy, coupled with chemometrics, was applied to develop a protocol that monitors chemical changes in common wheat under heat stress. Wheat plants at the three-leaf stage were subjected to heat stress at a 42 °C daily maximum temperature for 3 days, and this led to delayed growth in comparison to that of the control. Measurement of FTIR spectra and their principal component analysis showed partially overlapping features between heat-stressed and control leaves. In contrast, supervised machine learning through linear discriminant analysis (LDA) of the spectra demonstrated clear discrimination of heat-stressed leaves from the controls. Analysis of LDA loading suggested that several wavenumbers in the fingerprinting region (400-1800 cm-1) contributed significantly to their discrimination. Novel spectrum-based biomarkers were developed using these discriminative wavenumbers that enabled the successful diagnosis of heat-stressed leaves. Overall, these observations demonstrate the versatility of FTIR-based chemical fingerprints for use in heat-stress profiling in wheat.

Label-free molecular mapping and assessment of glycogen in C. elegans

Caenorhabditis elegans is an animal model frequently used in research on the effects of metabolism on organismal aging. This comes with a requirement for methods to investigate metabolite content, turnover, and distribution. The aim of our study was to assess the use of a label-free approach to determine both content and distribution of glycogen, the storage form of glucose, in C. elegans. To this end, we grew C. elegans worms under three different dietary conditions for 24-48 h, representing starvation, regular diet and a high glucose diet, followed by analysis of glycogen content. Glycogen analysis was performed on fixed individual whole worms using Raman micro-spectroscopy (RMS). Results were confirmed by comparison with two conventional assays, i.e. iodine staining of worms and enzymatic determination of glycogen. RMS was further used to assess overall lipid and protein content and distribution in the same samples used for glycogen analysis. Expectedly, both glycogen and lipid content were highest in worms grown on a high glucose diet, lower in regularly fed, and lowest in starved nematodes. In summary, RMS is a method suitable for analysis of glycogen content in C. elegans that has the advantage over established methods that (i) individual worms (rather than hundreds per sample) can be analyzed, (ii) glycogen distribution can be assessed at subcellular resolution and (iii) the distribution patterns of other macromolecules can be assessed from the same worms. Thus, RMS has the potential to be used as a sensitive, accurate, cost-effective and high throughput method to evaluate glycogen stores in C. elegans.

Salvia hispanica L. (chia) seeds oil extracts reduce lipid accumulation and produce stress resistance in Caenorhabditis elegans

Background

Salvia hispanica seeds have been commonly used by people that seek healthy habits through natural foods to reduce cholesterol and triacylglycerides levels, however, the evidences that support this assumption are still scarce in literature. Here, we aimed to evaluate the lipid lowering effects of chia by using Caenorhabditis elegans as animal model, a nematode that has proven its usefulness for lipid metabolism studies.

Methods

We prepared hexane (HE) and Bligh-Dyer (BDE) extracts, evaluated and compared their safety, antioxidant potential and their lipid-lowering activity in the worms.

Results

The characterization of both extracts demonstrated that there were no differences in their lipid composition; however, BDE depicted better antioxidant potential. Both extracts reduced worm’s survival from 2%, and reproduction was reduced following treatment with both extracts, though a more notable effect was observed in HE-treated worms. In addition, the non-toxic concentration of both extracts (1%) increased stress resistance against paraquat toxicity in an antidote paradigm. Notably, this same concentration of both extracts reduced lipid accumulation in obese worms, which was not caused by food deprivation.

Conclusions

Taken together, our data demonstrate that both extraction methods from chia seeds result in oils that are rich in mono and polyunsaturated fatty acids, which may modulate lipid accumulation and provide antioxidant resistance in C. elegans.