Fatty Aldehydes Research Articles

Comparative Metabolomics to Unravel the Biochemical Mechanism Associated with Rancidity in Pearl Millet (Pennisetum glaucum L.).

Despite being a highly nutritious and resilient cereal, pearl millet is not popular among consumers and food industries due to the short shelf-life of flour attributed to rapid rancidity development. The biochemical mechanism underlying rancidity, a complex and quantitative trait, needs to be better understood. The present study aims to elucidate the differential accumulation of metabolites in pearl millet that impact the rancidity process. Metabolite profiling was conducted on ten pearl millet genotypes with varying levels of rancidity-comprising high, low, and medium rancid genotypes-utilizing liquid chromatography and high-resolution mass spectrometry (LC-HRMS) at different accelerated ageing conditions. Through non-targeted metabolomic analysis, crucial metabolites associated with rancidity were identified across various biochemical pathways, including fatty acids, glycerophospholipids, sphingolipids, glycerol lipids, flavonoids, alkaloids, and terpenoids. Notably, metabolites such as fatty aldehydes, fatty alcohols, fatty esters, fatty acyls, fatty esters, and fatty amides were significantly elevated in high rancid genotypes, indicating their involvement in the rancidity process. These fatty acids-related metabolites further break down into saturated and unsaturated fatty acids. Four key fatty acids-stearic, palmitic, linoleic and linolenic acid-were quantified in the ten pearl millet genotypes, confirming their role in rancidity development. This investigation promises novel insights into utilizing metabolomics to understand the biochemical processes and facilitate precision breeding for developing low-rancidity pearl millet lines.

Lipidomics unveils changes in oxidised lipids in human breast milk by high‐pressure processing

SummaryHuman breast milk is a complex fluid rich in bioactive molecules crucial for infant growth and development. Global health organisations recommend exclusive breastfeeding to optimise infant health. In cases where maternal milk is unavailable, donor breast milk from human milk banks (HMBs) serves as an essential alternative. Currently, human breast milk preservation relies on Holder pasteurisation (HoP), which, while effective at pathogen inactivation, can compromise breast milk's nutritional and biological properties. High‐pressure processing (HPP) is an alternative pasteurisation method that utilises high pressure to kill pathogens without degrading nutrition. This study examined HPP's impact on donor breast milk lipids, sugars and antioxidants. Metabolomics reveals diverse bioactive compounds, including lipids, polyphenols and polyketides, elucidating breast milk's complexity. Some lipid subclasses respond to HPP; ceramides decreased under both treatments, while fatty aldehydes and esters increased under specific HPP conditions. Additionally, we quantified oxidised lipids, notably dietary oxysterols (DOxS), known for pro‐oxidant and pro‐inflammatory properties. These findings enhance understanding of HPP targeted approaches and breast milk's complexity, contributing to innovative milk preservation techniques that could advance specialised infant nutrition and assist donor milk banking systems.

Rapid pyrolysis of cellulose: Revealing the role of volatile matter and char structure evolution

The complexity of the cellulose structure hinders its energy conversion and utilization. Pyrolysis is not only an independent thermochemical conversion technology but also a necessary stage in the gasification process. The real-time capture of volatile components in cellulose pyrolysis is difficult, and the evolution of char structures is lacking, which is extremely challenging. In this work, elemental analysis, industrial analysis, thermogravimetric analysis, infrared spectroscopy (FTIR), Raman spectroscopy (Raman), and X-ray diffraction spectroscopy (XRD) were used to characterize the raw materials and products. Combined with rapid pyrolysis experiments, the pathways of cellulose pyrolysis volatiles and char structure evolution were explored. Dehydrated sugars are the initial products formed below 350 ℃, which quickly dehydrate to form furan compounds at 400 ℃ and then break CC bonds at 600 ℃ to generate fatty aldehydes, ketones, and carboxylic acids. Biochar generated at low temperatures (<300°C) has strong lipid solubility. An increase in pyrolysis temperature leads to a continuous decrease in the content of H and O in biochar, which destroys its functional groups and physical structure, and ultimately tends to form graphite-type char with aromatic structures. Based on the correlation between the volatile matter release characteristics and the evolution of the semichar structure, a cellulose pyrolysis pathway was established, providing theoretical support for the high-value utilization of cellulose.

Eryngial: An α,β-Unsaturated Fatty Aldehyde as the Major Phytotoxin in Spiny Coriander (Eryngium foetidum L.) Essential Oil.

Weed species many times possess allelochemicals as a part of their survival strategy. These metabolites can be potential targets in search of natural phytotoxins. This study aims to evaluate the phytotoxic ability of fatty aldehyde-rich essential oil from spiny coriander (Eryngium foetidum) leaves, also known as fitweed or spiritweed and to further identify the active phytotoxins. This oil dose-dependently inhibited the wheatgrass coleoptile and radicle growth in multiple bioassays with half maximal inhibitory concentration (IC50) 30.6-56.7 μg/mL, while exhibiting a less pronounced effect on the germination (IC50 181.8 μg/mL). The phytotoxicity assessment of two oil constituents identified eryngial (trans-2-dodecenal), exclusively major fatty aldehydic constituent as the potent growth inhibitor with IC50 in the range 20.8-36.2 μg/mL during an early phase of wheatgrass emergence. Eryngial-inspired screening of eleven saturated fatty aldehydes and alcohols did not find a significantly higher phytotoxic potency. In an open vessel, eryngial as the supplementation in agar medium, dose-dependently inhibited the growth of pre-germinated seeds of one monocot (bermudagrass) and one dicot (green amaranth) weed species with IC50 in the range 23.8-65.4 μg/mL. The current study identified eryngial, an α,β-unsaturated fatty aldehyde of coriander origin to be a promising phytotoxic candidate for weed control.

Insight into flavor changes in bighead carp (Aristichthys nobilis) fillets during storage based on enzymatic, microbial, and metabolism analysis

The flavor alterations in bighead carp subjected to varying storage temperatures and the underlying metabolic mechanism were elucidated. Analysis of volatile flavor compounds, electronic nose, free amino acids, ATP-related compounds, and sensory evaluations uncovered a progressive flavor deterioration during storage, especially at 25 °C. Metabolomics-based flavor relating component profiling analysis showed that free fatty acids formed various fatty aldehydes including (E, E)-2,4-heptadienal and nonanal under lipoxygenase catalysis. Alcohol dehydrogenase and alcohol acyltransferases were intimately involved in alcohol and ester generation, while alkaline phosphatase, 5′-nucleotidase, and acid phosphatase were closely associated with IMP, Hx, and HxR conversion, respectively. Aeromonas, Serratia, Lactococcus, Pseudomonas, and Peptostreptococcus notably influenced flavor metabolism and enzyme activities. The metabolism disparities of valine, leucine, isoleucine, lysine, and α-linolenic acid could be the primary factors contributing to flavor metabolism distinctions. This study offers novel insights into the flavor change mechanisms and potential regulation strategies of bighead carp during storage.

Highly sensitive analysis of fatty aldehydes in vegetable oils using a novel coumarin-based fluorescent probe by HPLC for quality control

A novel fluorescent probe, 3-(4-((hydroxylamino)methyl)-1H-pyrazol-1-yl)-7-methoxyl coumarin (HAPMC), has been designed and synthesized. The compound exhibits exceptional fluorescence properties due to a coumarin-pyrazolyl fluorophore. Moreover, it incorporates an N-hydroxylamine functional group capable of reacting with aldehydes to yield nitrone derivatives under mild conditions. This unique combination renders it an ideal derivatization reagent for aldehyde analysis. A standard method was established for the quantitative analysis of eight fatty aldehydes by utilizing high-performance liquid chromatography with fluorescence detection (HPLC-FLD) and a pre-column derivatization process, which has low detection limits (0.3–1.2 nM), satisfactory reproducibility (intraday and interday relative standard deviations in the range of 1.29 %-2.92 % and 1.73 %-3.45 %), and an extensive linear range (25–5000 nM) with excellent linearity (R2 ≥ 0.9989). The spiked recoveries of the fatty aldehydes range from 89.6 % to 106.0 %. The greenness and sustainability of our approach are reinforced by evaluations conducted with the AGREE and RGB 12 algorithms. The established method was successfully applied to the qualitative and quantitative detection of fatty aldehydes in nine real vegetable oil samples, including peanut, canola, rice, soybean, olive, rapeseed, corn, sunflower, and blended oils. The fatty aldehydes are known to have adverse effects on human health due to their carcinogenic and mutagenic properties. The findings revealed that hexanal and nonanal were the most prevalent saturated fatty aldehydes, with a notable increase in the total aldehyde concentration observed as the temperature and duration of heating increased. Compared to alternative analytical techniques, this pre-column derivatization method utilizing HAPMC displayed simplicity, reliability, and sensitivity. The results demonstrate the potential for broad application of this approach in various important research domains, including food quality control, environmental monitoring, and medical research.

Wearable solid-phase microextraction sampling for enhanced detection of volatile analytes in human ears

BackgroundInvestigating ear at molecule level is challenging task, since there is a lack of molecular detection by traditional diagnosis techniques such as otologic endoscopy, ear swab culture, and imaging diagnostic technique. Therefore, new development of noninvasive, highly sensitive, and convenient analytical method for investigating human ears is highly needed. ResultsWe developed a wearable sampling device for extracting trace analytes in ear by fixing solid-phase microextraction fibers into modified earmuffs (SPME-in-earmuffs). After sampling, SPME fiber was coupled with gas chromatography-mass spectrometry (GC-MS) for identification and quantification of extracted analytes. Enhanced detection of various analytes such as volatile metabolites, exposures, and therapeutic drugs of ears were demonstrated in this work. Particularly, sport-induced metabolic changes such as fatty acids, aldehyde compounds and oxidative produces were found from human ears using this method. Acceptable analytical performances were obtained by using this newly developed method for detecting ear medicines, e.g., low limit of detection (LOD, 0.005–0.021 ng/mL) and limit of quantification (LOQ, 0.018–0.071 ng/mL), excellent linear dynamic responses (R2 > 0.99, ranging from 0.050–8.00 ng/mL), good relative standard deviations (RSDs, 13.19 % ∼ 21.40 %, n = 6) and accuracy (84.43–150.18 %, n = 6) at different concentrations. SignificanceFor the first time, this work provides a simple, convenient, and wearable microextraction method for enhanced detection of trace volatiles in human ears. The enclosed space between ear and earmuff allows headspace SPME sampling of volatile analytes, and thus provides a new wearable method for monitoring ear metabolites and human exposures, showing potential applications in human health, disease diagnosis, and sport science.

A Novel Data Fusion Strategy of GC-MS and 1H NMR Spectra for the Identification of Different Vintages of Maotai-flavor Baijiu.

Counterfeit Baijiu has been emerging because of the price variances of real-aged Chinese Baijiu. Accurate identification of different vintages is of great interest. In this study, the combination of gas chromatography-mass spectrometry (GC-MS) and proton nuclear magnetic resonance (1H NMR) spectroscopy was applied for the comprehensive analysis of chemical constituents for Maotai-flavor Baijiu. Furthermore, a novel data fusion strategy combined with machine learning algorithms has been established. The results showed that the midlevel data fusion combined with the random forest algorithm were the best and successfully applied for classification of different Baijiu vintages. A total of 14 differential compounds (belonging to fatty acid ethyl esters, alcohols, organic acids, and aldehydes) were identified, and used for evaluation of commercial Maotai-flavor Baijiu. Our results indicated that both volatiles and nonvolatiles contributed to the vintage differences. This study demonstrated that GC-MS and 1H NMR spectra combined with a data fusion strategy are practical for the classification of different vintages of Maotai-flavor Baijiu.

One-Pot Biocatalytic Route from Alkanes to α,ω-Diamines by Whole-Cell Consortia of Engineered Yarrowia lipolytica and Escherichia coli.

Metabolically engineered microbial consortia can contribute as a promising production platform for the supply of polyamide monomers. To date, the biosynthesis of long-chain α,ω-diamines from n-alkanes is challenging because of the inert nature of n-alkanes and the complexity of the overall synthesis pathway. We combined an engineered Yarrowia lipolytica module with Escherichia coli modules to obtain a mixed strain microbial consortium that could catalyze an efficient biotransformation of n-alkanes into corresponding α,ω-diamines. The engineered Y. lipolytica strain was constructed (YALI10) wherein the two genes responsible for β-oxidation and the five genes responsible for the overoxidation of fatty aldehydes were deleted. This newly constructed YALI10 strain expressing transaminase (TA) could produce 0.2 mM 1,12-dodecanediamine (40.1 mg/L) from 10 mM n-dodecane. The microbial consortia comprising engineered Y. lipolytica strains for the oxidation of n-alkanes (OM) and an E. coli amination module (AM) expressing an aldehyde reductase (AHR) and transaminase (TA) improved the production of 1,12-diamine up to 1.95 mM (391 mg/L) from 10 mM n-dodecane. Finally, combining the E. coli reduction module (RM) expressing a carboxylic acid reductase (CAR) and an sfp phosphopantetheinyl transferase with OM and AM further improved the production of 1,12-diamine by catalyzing the reduction of undesired 1,12-diacids into 1,12-diols, which further undergo amination to give 1,12-diamine as the target product. This newly constructed mixed strain consortium comprising three modules in one pot gave 4.1 mM (41%; 816 mg/L) 1,12-diaminododecane from 10 mM n-dodecane. The whole-cell consortia reported herein present an elegant "greener" alternative for the biosynthesis of various α,ω-diamines (C8, C10, C12, and C14) from corresponding n-alkanes.

Review of Allelopathy in Green Tides: The Case of Ulva prolifera in the South Yellow Sea.

The proliferation of large green macroalgae in marine environments has led to the occurrence of green tides, particularly in the South Yellow Sea region of China, where Ulva prolifera has been identified as the primary species responsible for the world's largest green tide events. Allelopathy among plants is a critical factor influencing the dynamics of green tides. This review synthesizes previous research on allelopathic interactions within green tides, categorizing four extensively studied allelochemicals: fatty acids, aldehydes, phenols, and terpenes. The mechanisms by which these compounds regulate the physiological processes of green tide algae are examined in depth. Additionally, recent advancements in the rapid detection of allelochemicals are summarized, and their potential applications in monitoring green tide events are discussed. The integration of advanced monitoring technologies, such as satellite observation and environmental DNA (eDNA) analysis, with allelopathic substance detection is also explored. This combined approach addresses gaps in understanding the dynamic processes of green tide formation and provides a more comprehensive insight into the mechanisms driving these phenomena. The findings and new perspectives presented in this review aim to offer valuable insights and inspiration for researchers and policymakers.

Investigation of aroma components obtained by HS-SPME (Headspace-solid phase microextraction) method of wild strawberry (Fragaria vesca L.) and strawberry (Fragaria x ananassa Duch.) fruits

Wild strawberries (Fragaria vesca) are in the category of non-wood forest products due to their unique fragrance, aroma, and natural ability to grow. In this study, aroma components of wild strawberry (Fragaria vesca) and strawberry (Fragaria x ananassa) fruits were determined by Headspace-Solid Phase Micro-Extraction technique combined with Gas chromatography-mass spectrometry (HS-SPME/GC-MS). In addition, it aimed to compare the results of both fruits with each other by chemical classification of the aroma components determined from wild strawberry and strawberry fruits. As a result of the HS-SPME/GC-MS analysis; 50 and 76 aroma components were determined in wild strawberry and strawberry fruits, respectively. The structure of aroma components was defined as 97.63% of wild strawberries and 98.26% of strawberries. The main components in the aroma compounds are 2-undecanone (10.38%), γ-decalactone (8.81%), and eugenol (7.14%) in wild strawberry fruit; nerolidol (29.44%), γ-decalactone (26.36%) and bisabolol oxide II (4.23%) were found in strawberry fruits. In addition, chemical classes of identified aroma compounds were determined as ester, terpene or terpenoid, fatty acids, aldehyde, and ketone classes in Fragaria vesca and Fragaria x ananassa fruits. When the results are examined, it is seen that strawberry fruits are found to be higher than wild strawberry fruits in terms of percentage of aroma components, number of aroma components, and percentage of dominant components.

SNF1 plays a crucial role in the utilization of n-alkane and transcriptional regulation of the genes involved in it in the yeast Yarrowia lipolytica

Yarrowia lipolytica is an ascomycetous yeast that can assimilate hydrophobic carbon sources including oil and n-alkane. The sucrose non-fermenting 1/AMP-activated protein kinase (Snf1/AMPK) complex is involved in the assimilation of non-fermentable carbon sources in various yeasts. However, the role of the Snf1/AMPK complex in n-alkane assimilation in Y. lipolytica has not yet been elucidated. This study aimed to clarify the role of Y. lipolytica SNF1 (YlSNF1) in the utilization of n-alkane. The deletion mutant of YlSNF1 (ΔYlsnf1) exhibited substantial growth defects on n-alkanes of various lengths (C10, C12, C14, and C16), and its growth was restored through the introduction of YlSNF1. Microscopic observations revealed that YlSnf1 tagged with enhanced green fluorescence protein showed dot-like distribution patterns in some cells cultured in the medium containing n-decane, which were not observed in cells cultured in the medium containing glucose or glycerol. The RNA sequencing analysis of ΔYlsnf1 cultured in the medium containing n-decane exhibited 302 downregulated and 131 upregulated genes compared with the wild-type strain cultured in the same medium. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses suggested that a significant fraction of the downregulated genes functioned in peroxisomes or were involved in the metabolism of n-alkane and fatty acids. Quantitative real-time PCR analysis confirmed the downregulation of 12 genes involved in the metabolism of n-alkane and fatty acid, ALK1–ALK3, ALK5, ADH7, PAT1, POT1, POX2, PEX3, PEX11, YAS1, and HFD3. Furthermore, ΔYlsnf1 exhibited growth defects on the medium containing the metabolites of n-alkane (fatty alcohol and fatty aldehyde). These findings suggest that YlSNF1 plays a crucial role in the utilization of n-alkane in Y. lipolytica. This study provides important insights into the advanced biotechnological applications of this yeast, including the bioconversion of n-alkane to useful chemicals and the bioremediation of petroleum-contaminated environments.

Plasmalogen oxidation induces the generation of excited molecules and electrophilic lipid species.

Plasmalogens are glycerophospholipids with a vinyl ether linkage at the sn-1 position of the glycerol backbone. Despite being suggested as antioxidants due to the high reactivity of their vinyl ether groups with reactive oxygen species, our study reveals the generation of subsequent reactive oxygen and electrophilic lipid species from oxidized plasmalogen intermediates. By conducting a comprehensive analysis of the oxidation products by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS), we demonstrate that singlet molecular oxygen [O2 (1Δg)] reacts with the vinyl ether bond, producing hydroperoxyacetal as a major primary product (97%) together with minor quantities of dioxetane (3%). Furthermore, we show that these primary oxidized intermediates are capable of further generating reactive species including excited triplet carbonyls and O2 (1Δg) as well as electrophilic phospholipid and fatty aldehyde species as secondary reaction products. The generation of excited triplet carbonyls from dioxetane thermal decomposition was confirmed by light emission measurements in the visible region using dibromoanthracene as a triplet enhancer. Moreover, O2 (1Δg) generation from dioxetane and hydroperoxyacetal was evidenced by detection of near-infrared light emission at 1,270 nm and chemical trapping experiments. Additionally, we have thoroughly characterized alpha-beta unsaturated phospholipid and fatty aldehydes by LC-HRMS analysis using two probes that specifically react with aldehydes and alpha-beta unsaturated carbonyls. Overall, our findings demonstrate the generation of excited molecules and electrophilic lipid species from oxidized plasmalogen species unveiling the potential prooxidant nature of plasmalogen-oxidized products.

The Ameliorating Effect of Artificial Coffee from Mangrove Fruits (Rhizophora mucronata) on T Lymphocyte Cells and Renal Histopathology of BALB/c Mice Induced by Lipopolysaccharide

The potential of Rhizophora mucronata mangrove fruits as antioxidants is noteworthy, with promising prospects as nutraceuticals, particularly in their role as immunomodulators for T lymphocyte cells. R. mucronata fruits have been utilized by household industries in Indonesia as a coffee-like drink (artificial coffee). This study aims to determine the ability of mangrove fruit artificial coffee R. mucronata to stimulate T lymphocyte cells and renal histopathology conditions in LPS-induced mice animal models. This study also characterizes proximate characteristics, antioxidant capacity, and Gas Chromatography-Mass Spectrometry (GC-MS) screening of mangrove fruit artificial coffee compounds. The stages of this research included the process of mangrove fruit artificial coffee; analysis of proximate and caffeine; compounds screening (GC-MS) and toxicity prediction (Pro-Tox II); antioxidant capacity (DPPH); T lymphocyte cell expression (flow cytometry); and renal histopathological evaluation. The results showed moisture content (5.22±0.20%); ash (5.17±0.27%); protein (13.74±0.24%); fat (11.63±0.32%); carbohydrate (64.23±0.15%), caffeine (1.09±0.04%). GC-MS analysis showed that the compounds contained in artificial coffee were derivatives of fatty aldehyde, fatty acid, and cycloalkanes compound classes. Predicted toxicity of artificial coffee LD50 5000 mg/kg. Antioxidant capacity is classified as moderate (IC50 119.41±0.99µg/mL). Mangrove fruit artificial coffee can increase the relative number of CD4+CD62L+ by 14.68-29.48% and CD8+CD62L+ T lymphocyte cells by 12.60-30.33%. Artificial coffee can also increase the number of healthy cells and reduce the cells that undergo necrosis in the renal of LPS-induced mice. This study concluded that mangrove fruit artificial coffee R. mucronata positively affects T lymphocyte activation and mice renal cells’ protection from necrosis due to LPS induction.

Metabolic behavior of Aspergillus oryzae in salt-reduced soy sauce and its regulation for the brewing process

Soy sauce fermentation process initiates with the involvement of Aspergillus oryzae, which serves as the primary beneficiary in salt-reduced fermentation (SRF) process. This investigation aimed to scrutinize the metabolic activities of A. oryzae in salt-reduced soy sauce and examine its subsequent impacts on the microecology and flavor profile. SRF amplified the central carbon and protein metabolism of A. oryzae, leading to improved substrate utilization efficiency, which in turn facilitated the colonization of Lactobacillus and the maintenance of a co-occurrence equilibrium within the microbiota. Consequently, Ascomycetes established a fundamental module for aroma generation, exhibiting robust interconnections. SRF facilitated A. oryzae in supplying amino acid precursors vital to produce phenylacetaldehyde derivatives. Furthermore, SRF prompted an up-regulation of the β-oxidation pathway in A. oryzae, effectively suppressing the generation of undesirable fatty rancidity odor (fatty aldehyde) derived from fatty acids. These metabolic characteristics of A. oryzae play a pivotal role in enhancing the quality of salt-reduced soy sauce.

Evaluation of Distillery Fractions in Direct Methanol Fuel Cells and Screening of Reaction Products

Fuel cells represent an appealing avenue for harnessing eco-friendly energy. While their fuel supply traditionally stems from water electrolysis, an environmentally conscious approach also involves utilizing low-weight alcohols like methanol and ethanol. These alcohols, concentrated from sustainable sources within the enological by-product distillation process, offer a noteworthy contribution to the circular economy. This study delved into evaluating the efficacy of distillery fractions in powering methanol fuel cells. Beyond their energy-generation potential, the performed GC-MS analysis unveiled appreciable quantities of acetic acid resulting from the partial oxidation of ethanol. This revelation opens the door to intriguing possibilities, including the recovery and repurposing of novel compounds such as short-chain fatty acids (predominantly acetic acid), ketones, and aldehydes—establishing a link between sustainable energy production and the emergence of valuable by-product applications.

Dynamic relationships among pathways producing hydrocarbons and fatty acids of maize silk cuticular waxes.

The hydrophobic cuticle is the first line of defense between aerial portions of plants and the external environment. On maize (Zea mays L.) silks, the cuticular cutin matrix is infused with cuticular waxes, consisting of a homologous series of very long-chain fatty acids (VLCFAs), aldehydes, and hydrocarbons. Together with VLC fatty-acyl-CoAs (VLCFA-CoAs), these metabolites serve as precursors, intermediates and end-products of the cuticular wax biosynthetic pathway. To deconvolute the potentially confounding impacts of the change in silk microenvironment and silk development on this pathway, we profiled cuticular waxes on the silks of the inbreds B73 and Mo17, and their reciprocal hybrids. Multivariate interrogation of these metabolite abundance data demonstrates that VLCFA-CoAs and total free VLCFAs are positively correlated with the cuticular wax metabolome, and this metabolome is primarily affected by changes in the silk microenvironment and plant genotype. Moreover, the genotype effect on the pathway explains the increased accumulation of cuticular hydrocarbons with a concomitant reduction in cuticular VLCFA accumulation on B73 silks, suggesting that the conversion of VLCFA-CoAs to hydrocarbons is more effective in B73 than Mo17. Statistical modeling of the ratios between cuticular hydrocarbons and cuticular VLCFAs reveals a significant role of precursor chain length in determining this ratio. This study establishes the complexity of the product-precursor relationships within the silk cuticular wax-producing network by dissecting both the impact of genotype and the allocation of VLCFA-CoA precursors to different biological processes, and demonstrates that longer chain VLCFA-CoAs are preferentially utilized for hydrocarbon biosynthesis.

The white rot basidiomycete Gelatoporia subvermispora produces fatty aldehydes that enable fungal manganese peroxidases to degrade recalcitrant lignin structures.

The ability of some white rot basidiomycetes to remove lignin selectively from wood indicates that low molecular weight oxidants have a role in ligninolysis. These oxidants are likely free radicals generated by fungal peroxidases from compounds in the biodegrading wood. Past work supports a role for manganese peroxidases (MnPs) in the production of ligninolytic oxidants from fungal membrane lipids. However, the fatty acid alkylperoxyl radicals initially formed during this process are not reactive enough to attack the major structures in lignin. Here, we evaluate the hypothesis that the peroxidation of fatty aldehydes might provide a source of more reactive acylperoxyl radicals. We found that Gelatoporia subvermispora produced trans-2-nonenal, trans-2-octenal, and n-hexanal (a likely metabolite of trans-2,4-decadienal) during the incipient decay of aspen wood. Fungal fatty aldehydes supported the in vitro oxidation by MnPs of a nonphenolic lignin model dimer, and also of the monomeric model veratryl alcohol. Experiments with the latter compound showed that the reactions were partially inhibited by oxalate, the chelator that white rot fungi employ to detach Mn3+ from the MnP active site, but nevertheless proceeded at its physiological concentration of 1 mM. The addition of catalase was inhibitory, which suggests that the standard MnP catalytic cycle is involved in the oxidation of aldehydes. MnP oxidized trans-2-nonenal quantitatively to trans-2-nonenoic acid with the consumption of one O2 equivalent. The data suggest that when Mn3+ remains associated with MnP, it can oxidize aldehydes to their acyl radicals, and the latter subsequently add O2 to become ligninolytic acylperoxyl radicals.IMPORTANCEThe biodegradation of lignin by white rot fungi is essential for the natural recycling of plant biomass and has useful applications in lignocellulose bioprocessing. Although fungal peroxidases have a key role in ligninolysis, past work indicates that biodegradation is initiated by smaller, as yet unidentified oxidants that can infiltrate the substrate. Here, we present evidence that the peroxidase-catalyzed oxidation of naturally occurring fungal aldehydes may provide a source of ligninolytic free radical oxidants.

Insight into a traditional culinary practice: Late-stage addition of spiny coriander (Eryngium foetidum L.) in Indian cooking system

Spiny coriander (Eryngium foetidum L.) is a food flavouring herb with strong coriander-like odour. The leaves are traditionally used for flavouring the curries, boiled items, soups in Indian subcontinent and added during the final stage of cooking. The current study aimed to validate this traditional culinary knowledge on the addition of spiny coriander leaves and provide a scientific insight into this practice. To pursue the objective, fresh leaves were subjected to simulated open and close-vessel cooking conditions in Clevenger-type apparatus and pressure cooker, respectively. An extensive loss (∼43 %) in volatile flavours occurred after 30 min of open-vessel boiling and similarly for close-vessel process (∼39 %). However, the volatile composition, exclusively dominated by fatty aldehydes, especially trans-2-dodecenal (>70 %) remained practically unaltered throughout this process; rejecting the possibility of considerable transformation or degradation. Thus, boiling process during cooking promoted the loss of aromatic flavours through evaporation and justified the late-stage addition of spiny coriander to preserve its key flavours.

Deciphering the seasonal dynamics of microplastic morphotypes and associated co-contaminants along the northwest coast of India

In the present study, the northwest coast of India, bordering the Arabian Sea, was selected to evaluate the microplastic (MP) abundance. This is the first study to emphasize the effects of different seasons on MP distribution. The collected MPs were dried, segregated, and evaluated based on their morphotype, size, color, and polymer type. A total of 1756.6, 7326.6, and 202 particles/kg of sand were estimated in the pre-monsoon, monsoon and post-monsoon seasons, respectively, with a dominance of polypropylene (PP) type of plastic in the pre-monsoon and high-density polyethylene (HDPE) in monsoon and post-monsoon seasons. HDPE and PP collected MPs during the monsoon season were further characterized for associated contaminants. Metal absorbance was detected using SEM-EDX mapping and ICP-MS. The presence of organic compounds (OCs) was analyzed using GC-MS. MPs exhibit distinct associations with metals, among which the HDPE pellet morphotype exhibits a higher range of metal adsorption. Total 61 different OCs were associated with MPs. The HDPE pellets contained the highest amounts of hydrophobic organic compounds. PP pellets were found to contain triglycerides, fatty aldehydes, and alkaloids, along with HOCs. Among morphotypes, pellet forms of MPs were found to adsorb more contaminants. These co-contaminants infiltrate the study area through sewage runoff and shoreline debris deposition, subsequently interacting with MPs. Furthermore, the MP diversity was studied by employing the MP diversity integrated index, which suggests that most of the MP diversity was observed in the pre-monsoon period. The pollution load index employed an MP risk assessment, which presented a low degree of MP contamination. In contrast, the polymer hazard index was calculated as 21650.3 in post-monsoon, placing the area under the extreme danger category. It is evident from the data that the types of MP is more important than their number. Thus, MP morphotypes have importance in the adsorption of co-contaminants.