Nitrosative deamination of 2'-deoxyguanosine and DNA by nitrite, and antinitrosating activity of β-carboline alkaloids and antioxidants

Pea Protein Isolate as a Meat Substitute in Canned Pork Pâté: Nutritional, Technological, Oxidative, and Sensory Properties

This study investigated the feasibility of replacing pork meat with pea protein isolate in canned pâtés at proportions ranging from 12.5% to 50%. The results indicated that protein reformulation did not significantly impact the protein content and lipid oxidation of the pâtés. Reformulated products exhibited a decrease in a∗ values and an increase in b∗ values. These color changes were also sensorially identified in the Check-All-That-Apply (CATA) test, where the reformulated pâtés were associated with attributes such as 'yellow color' and 'unpleasant color', which were inversely related to product acceptance. The protein reformulation reduced the hardness, gumminess, and chewiness parameters of the pâtés. These textural changes were positively reflected in the CATA test, where the reformulated products were characterized by attributes like 'soft texture', 'pleasant texture', and 'good spreadability', which strongly correlated with higher consumer acceptance. Notably, pâtés with 37.5% and 50% substitutions of pork meat with pea protein showed acceptability levels comparable to the control, and those with up to a 25% substitution exhibited superior sensory acceptability. However, the color alteration suggests the need for future optimization, such as using natural colorants. In summary, the results of this study not only validate the feasibility of replacing pork meat with pea protein in pâtés but also offer valuable insights for future investigations to develop more innovative and sustainable meat products.

Mutagens in commercial food processing and its microbial transformation

Mutagens are chemical molecules that have the ability to damage DNA. Mutagens can enter into our body upon consumption of improperly cooked or processed food products such as high temperature or prolonged cooking duration. Mutagens are found in the food products can be classified into N-nitroso derivatives, polycyclic aromatic hydrocarbons, and heterocyclic aromatic amines. Food products with high fat and protein content are more prone to mutagenic formation. Microorganisms were found to be a potent weapon in the fight against various mutagens through biotransformation. Therefore, searching for the microorganisms which have the ability to transform mutagens and the development of techniques for the identification as well as detection of mutagens in food products is much needed. In the future, methods for the identification and detection of these mutagens as well as the identification of new and more potent microorganisms which can transform mutagens into non-mutagens are much needed.

β-Carboline Alkaloids in Soy Sauce and Inhibition of Monoamine Oxidase (MAO)

Monoamine oxidase (MAO) oxidizes neurotransmitters and xenobiotic amines, including vasopressor and neurotoxic amines such as the MPTP neurotoxin. Its inhibitors are useful as antidepressants and neuroprotectants. This work shows that diluted soy sauce (1/3) and soy sauce extracts inhibited human MAO-A and -B isozymes in vitro, which were measured with a chromatographic assay to avoid interferences, and it suggests the presence of MAO inhibitors. Chromatographic and spectrometric studies showed the occurrence of the β-carboline alkaloids harman and norharman in soy sauce extracts inhibiting MAO-A. Harman was isolated from soy sauce, and it was a potent and competitive inhibitor of MAO-A (0.4 µM, 44 % inhibition). The concentrations of harman and norharman were determined in commercial soy sauces, reaching 243 and 52 μg/L, respectively. Subsequently, the alkaloids 1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (THCA) and 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) were identified and analyzed in soy sauces reaching concentrations of 69 and 448 mg/L, respectively. The results show that MTCA was a precursor of harman under oxidative and heating conditions, and soy sauces increased the amount of harman under those conditions. This work shows that soy sauce contains bioactive β-carbolines and constitutes a dietary source of MAO-A and -B inhibitors.

Easy Nitrite Analysis of Processed Meat with Colorimetric Polymer Sensors and a Smartphone App

We have developed an in situ methodology for determining nitrite concentration in processed meats that can also be used by unskilled personnel. It is based on a colorimetric film-shaped sensory polymer that changes its color upon contacting the meat and a mobile app that automatically calculates the manufacturing and residual nitrite concentration by only taking digital photographs of sensory films and analyzing digital color parameters. The film-shaped polymer sensor detects nitrite anions by an azo-coupling reaction, since they activate this reaction between two of the four monomers that the copolymer is based on. The sensory polymer is complemented with an app, which analyzes the color in two different digital color spaces (RGB and HSV) and performs a set of 32 data fittings representing the concentration of nitrite versus eight different variables, finally providing the nitrite concentration of the test samples using the best fitting curve. The calculated concentration of nitrite correlates with a validated method (ISO 2918: 1975) usually used to determine nitrite, and no statistically significant difference between these methods and our proposed one has been found in our study (26 meat samples, 8 prepared, and 18 commercial). Our method represents a great advance in terms of analysis time, simplicity, and orientation to use by average citizens.

Melatonin, Its Metabolites and Their Interference with Reactive Nitrogen Compounds

Melatonin and several of its metabolites are interfering with reactive nitrogen. With the notion of prevailing melatonin formation in tissues that exceeds by far the quantities in blood, metabolites come into focus that are poorly found in the circulation. Apart from their antioxidant actions, both melatonin and N¹-acetyl-5-methoxykynuramine (AMK) downregulate inducible and inhibit neuronal NO synthases, and additionally scavenge NO. However, the NO adduct of melatonin redonates NO, whereas AMK forms with NO a stable product. Many other melatonin metabolites formed in oxidative processes also contain nitrosylatable sites. Moreover, AMK readily scavenges products of the CO₂-adduct of peroxynitrite such as carbonate radicals and NO₂. Protein AMKylation seems to be involved in protective actions.

Neuropharmacological potentials of β-carboline alkaloids for neuropsychiatric disorders

Neuropsychiatric disorders are diseases of the central nervous system (CNS) which are characterised by complex pathomechanisms that including homeostatic failure, malfunction, atrophy, pathology remodelling and reactivity anomaly of the neuronal system where treatment options remain challenging. β-Carboline (βC) alkaloids are scaffolds of structurally diverse tricyclic pyrido[3,4-b]indole alkaloid with vast occurrence in nature. Their unique structural features which favour interactions with enzymes and protein receptor targets account for their potent neuropharmacological properties. However, our current understanding of their biological mechanisms for these beneficial effects, especially for neuropsychiatric disorders is sparse. Therefore, we present a comprehensive review of the scientific progress in the last two decades on the prospective pharmacology and physiology of the βC alkaloids in the treatment of some neuropsychiatric conditions such as depression, anxiety, Alzheimer's disease, Parkinson's disease, brain tumour, essential tremor, epilepsy and seizure, licking behaviour, dystonia, agnosia, spasm, positive ingestive response as demonstrated in non-clinical models. The current evidence supports that βC alkaloids offer potential therapeutic agents against most of these disorders and amenable for further drug design.

Single-nucleotide editing for zebra3 and wsl5 phenotypes in rice using CRISPR/Cas9-mediated adenine base editors

The CRISPR/Cas9-mediated base editing technology can efficiently generate point mutations in the genome without introducing a double-strand break (DSB) or supplying a DNA donor template for homology-directed repair (HDR). In this study, adenine base editors (ABEs) were used for rapid generation of precise point mutations in two distinct genes, OsWSL5, and OsZEBRA3 (Z3), in both rice protoplasts and regenerated plants. The precisely engineered point mutations were stably inherited to subsequent generations. These single nucleotide alterations resulted in single amino acid changes and associated wsl5 and z3 phenotypes as evidenced by white stripe leaf and light green/dark green leaf pattern, respectively. Through selfing and genetic segregation, transgene-free, base edited wsl5 and z3 mutants were obtained in a short period of time. We noticed a novel mutation (V540A) in Z3 locus could also mimic the phenotype of Z3 mutation (S542P). Furthermore, we observed unexpected non- A/G or T/C mutations in the ABE editing window in a few of the edited plants. The ABE vectors and the method from this study could be used to simultaneously generate point mutations in multiple target genes in a single transformation and serve as a useful base editing tool for crop improvement as well as basic studies in plant biology.

Microbial biotransformation of N-nitro-, C-nitro-, and C-nitrous-type mutagens by Lactobacillus delbrueckii subsp. bulgaricus in meat products

Processed meats are classified by the International Agency for Research on Cancer (IARC) as carcinogenic to humans. However, information on the responsible agents and the influence of industrial processing on the increased risk of cancer is still lacking. This study aimed to use cultures of Lactobacillus delbrueckii subsp. bulgaricus LB-UFSC 01 to biodegrade harmful C-nitrous, N-nitro, and C-nitro compounds in processed meat matrix. Firstly, positive results for ethylnitrolic acid (ENA) (>5.00 μg kg^-1) and 2-methyl-1,4-dinitro-pyrrole (DNMP) (>12.0 μg kg^-1) were obtained in mortadellas produced under different experimental conditions employing preservatives and antioxidants. Mortadellas containing nitrite and sorbate in the ratio of 8:1 (w/w) yielded the highest concentrations of mutagens. However, the treatment with the LB-UFSC 01 culture was able to modulate the harmful compounds in the mortadella samples. Several analytical methods employing liquid chromatography coupled to mass spectrometry and statistical models were employed to identify the metabolites and reaction routes during microbial biotransformation. For the first time, relevant information regarding the formation and degradation of ENA and DNMP in a processed meat model simulating real conditions was presented.

Quercetin attenuates the hyperoxic lung injury in neonatal mice: Implications for Bronchopulmonary dysplasia (BPD)

Quercetin (QU) is one of the most common flavonoids that are present in a wide variety of fruits, vegetables, and beverages. This compound possesses potent anti-inflammatory and anti-oxidant properties. Supplemental oxygen is routinely administered to premature infants with pulmonary insufficiency. However, hyperoxia is one of the major risk factors for the development of bronchopulmonary dysplasia (BPD), which is also termed chronic lung disease in premature infants. Currently, no preventive approaches have been reported against BPD. The treatment of BPD is notably limited to oxygen administration, ventilatory support, and steroids. Since QU has been shown to be effective in reducing inflammation and oxidative stress in various disease models, we hypothesized that the postnatal QU treatment of newborn mice will protect against hyperoxic lung injury by the upregulation of the phase I (CYP1A/B) and/or phase II, NADPH quinone reductase enzymes. Newborn C57BL/6J mice within 24 h of birth with the nursing dams were exposed to either 21% O₂ (air) and/or 85% O₂ (hyperoxia) for 7 days. The mice were treated, intraperitoneally (i.p.) once every other day with quercetin, at a concentration of 20 mg/kg, or saline alone from postnatal day (PND) 2-6. The mice were sacrificed on day 7, and lung and liver tissues were collected. The expression levels of CYP1A1, CYP1B1, NQO1 proteins and mRNA as well as the levels of MDA-protein adducts were analyzed in lung and liver tissues. The findings indicated that QU attenuated hyperoxia-mediated lung injury by reducing inflammation and improving alveolarization with decreased number of neutrophil and macrophage infiltration. The attenuation of this lung injury correlated with the upregulation of CYP1A1/CYP1B1/NQO1 mRNA, proteins and the down regulation of NF-kB levels and MDA-protein adducts in lung and liver tissues. The present study demonstrated the potential therapeutic value of quercetin in the prevention and/or treatment of BPD.