Biogenic amines (BAs) are crucial markers of meat spoilage. Developing practical and effective BAs detection methods is essential for monitoring meat freshness and ensuring daily consumption safety. This study prepared several naphthalene-based fluorescent compounds to visually monitor meat freshness in real-time. These probes show a colorimetric fluorescence response to putrescine and cadaverine (typical spoilage indicators) through nucleophilic addition/elimination reaction. The detectability of these probes can be optimized by altering the electronegativity and substitution position of the recognition group. Among these compounds, 2-((6-(4-(diphenylamino)phenyl)naphthalen-2-yl)methylene)malono nitrile (TNMA) demonstrated exceptional sensing performance toward putrescine and cadaverine, including high-contrast fluorescence color transition (red to blue), rapid response times (∼30 s), high selectivity and sensitivity (detection limit for putrescine: 2.69 ppm, cadaverine: 6.11 ppm). Furthermore, the B/R values of TNMA test strips output by RGB analysis presented a linear correlation with total volatile basic nitrogen (TVBN, an international standard for evaluating food spoilage) values in pork. Based on this correlation, we utilized smartphone applications to construct an intelligent evaluation system, enabling visual monitoring of pork, chicken, and shrimp freshness under various storage conditions. The TNMA-based system offers a reliable platform for real-time, portable and visual monitoring of meat freshness for consumers and suppliers in the food industry.

BACKGROUND: Diffuse gliomas are among the most common brain tumors in adults and are associated with a dismal prognosis, especially in patients with glioblastoma. To date, tumor tissue acquisition is mandatory for conclusive diagnosis and therapeutic decision-making. In this study, we aimed to identify possible diagnostic and prognostic biomarkers in cerebrospinal fluid (CSF) and blood.
METHODS: During glioma surgery at our institution, CSF and blood samples were collected from patients. Subsequently, targeted metabolomics analysis was used to detect and quantify circulating metabolites. The metabolome profiles of glioma patients were compared with those of patients in a control group who had undergone neurosurgery for other entities, such as nonglial tumors or hydrocephalus, and were correlated with established glioma diagnostic molecular markers.
RESULTS: In this study, a total of 30 glioma patients were included, along with a control group of 21 patients without glioma. Serum metabolomic analysis did not detect any significant differences between the groups, whereas CSF-metabolome analysis revealed increased levels of six metabolites in glioma patients. Among these, the most pronounced differences were found for the biogenic amine putrescine (p = 0.00005). p-Cresol sulfate was identified as a potential CSF marker for determining isocitrate dehydrogenase (IDH) status in glioma patients (p = 0.0037).
CONCLUSIONS: CSF-metabolome profiling, unlike blood profiling, shows promise as a diagnostic tool for glioma patients with the potential to assign molecular subtypes. The next step will involve a larger multicenter study to validate these findings, with the ultimate objective of integrating CSF metabolomics analysis into clinical practice.

Natural polyamines, including spermidine (SPD), spermine (SPM) and putrescine (PUT), are evolutionarily conserved endogenous molecules crucially involved in central cellular processes. Their physiological importance may extend to the maintenance of cognitive function during aging. However, limited population-based epidemiological studies have explored the link between dietary polyamines and dementia risk. This study was a prospective analysis of 77,092 UK Biobank participants aged ≥ 60 years without dementia at baseline. We used Cox proportional hazard regression models to explore the associations between dietary polyamines and the risk of dementia, and restricted cubic splines to test the non-linear relationships. During a median follow-up of 12 years, 1087 incidents of all-cause dementia cases occurred, including 450 Alzheimer\'s disease (AD) cases and 206 vascular dementia (VD) cases. The fully adjusted hazard ratios (HRs) for the upper fourth quintile of dietary SPD, in comparison with the lowest quintile of intake, were 0.68 (95% confidence interval [95% CI]: 0.66-0.83) for the risk of all-cause dementia, 0.62 (95% CI: 0.45-0.85) for AD and 0.56 (95% CI: 0.36-0.88) for VD, respectively. A 26% reduction in dementia risk [HR: 0.74, (95% CI: 0.61-0.89)] and a 47% reduction in AD [HR: 0.53, (95%CI: 0.39-0.72)] were observed comparing the third with the lowest quintiles of dietary SPM. Dietary PUT was only associated with a reduced risk of all-cause dementia in the fourth quintile [HR (95% CI): 0.82 (0.68-0.99)]. Reduced risk was not found to be significant across all quintiles. There were \'U\'-shaped relationships found between dietary polyamines and all-cause dementia, AD and VD. Stratification by genetic predisposition showed no significant effect modification. Optimal intake of polyamines was linked to a decreased risk of dementia, with no modification by genetic risk. This potentially suggests cognitive benefits of dietary natural polyamines in humans.

Substantial proteolysis occurs and free amino acids can be degraded to biogenic amines by decarboxylation during stylo (Stylosanthes guianensis) ensiling. High biogenic amine concentrations in silage are harmful to the health of ruminant animals. The purposes of this work were to (1) analyze the biogenic amines and amino acids concentrations, bacterial composition, and fermentation profile of spontaneously fermented stylo silage, (2) explore the effect of formic acid or sugar additive on these silage parameters, and (3) further reveal the correlations between silage amines and fermentation parameters, amino acids, and bacteria. Freshly chopped stylo was treated with distilled water (control), formic acid (4 mL/kg), and sugar (20 g/kg) and fermented for 28 days. The results indicated that putrescine (321 mg/kg dry matter), cadaverine (384 mg/kg dry matter), and tyramine (127 mg/kg dry matter) rapidly increased in concentration and become predominant in the control silage after 28 days of fermentation. Applying formic acid and sugar at ensiling, especially the acidifier, significantly decreased putrescine, cadaverine, tyramine, and total biogenic amine concentrations compared with the control treatment (p < 0.0001). Clostridium pabulibutyricum, Weissella cibaria and W. paramesenteroides were the predominant bacteria in the control silage, and the application of both additives remarkably lowered their relative abundance in comparison with the control treatment (p < 0.001). Correlation analysis showed that putrescine, cadaverine, and tyramine were positively related to pH, butyric acid, non-protein nitrogen, and ammonia nitrogen (p < 0.01). These amines also had significant correlations with C. pabulibutyricum, W. cibaria and W. paramesenteroides (p < 0.001). Putrescine, cadaverine, and tyramine were the main biogenic amines and C. pabulibutyricum was the predominant undesirable bacterium in naturally fermented stylo silage. C. pabulibutyricum, W. cibaria and W. paramesenteroides were positively related to putrescine, cadaverine, and tyramine formation. The application of formic acid or sugar significantly reduced the undesirable bacterial population and improved the fermentation and hygienic quality of the stylo silage. These findings lay the foundation for further elucidating the microbial mechanism underlying the main biogenic amine formation during fermentation of stylo silage.

The ornithine-urea cycle (OUC) in fungal cells has biotechnological importance and many physiological functions and is closely related to the acetyl glutamate cycle (AGC). Fumarate can be released from argininosuccinate under the catalysis of argininosuccinate lyase in OUC which is regulated by the Ca2+ signaling pathway and over 93.9 ± 0.8 g/L fumarate can be yielded by the engineered strain of Aureobasidium pullulans var. aubasidani in the presence of CaCO3. Furthermore, 2.1 ± 0.02 mg of L-ornithine (L-Orn)/mg of the protein also can be synthesized via OUC by the engineered strains of Aureobasidum melanogenum. Fumarate can be transformed into many drugs and amino acids and L-Orn can be converted into siderophores (1.7 g/L), putrescine (33.4 g/L) and L-piperazic acid (L-Piz) (3.0 g/L), by different recombinant strains of A. melanogenum. All the fumarate, L-Orn, siderophore, putrescine and L-Piz have many applications. As the yeast-like fungi and the promising chassis, Aureobasidium spp, have many advantages over any other fungal strains. Further genetic manipulation and bioengineering will enhance the biosynthesis of fumarate and L-Orn and their derivates.
OUC in fungal cells has biotechnological importance and many physiological functions; OUC is closely related to acetyl glutamate cycle (AGC). Fumarate, L-Orn, siderophore, putrescine and L-Piz produced from OUC have many applications.

Drought, which adversely affects plant growth and continuity of life and reduces product yield and quality, is one of the most common abiotic stresses at the globally. One of the polyamines that regulates plant development and reacts to abiotic stressors, including drought stress, is Putrescine (Put). This study compared the physiological and molecular effects of applying exogenous Put (10 µM) to barley (Hordeum vulgare cv. Burakbey) under drought stress (- 6.30 mPa PEG 6000). The 21-day drought stress imposed on the barley plant had a strong negative effect on plant metabolism in all experimental groups. Exogenous Put treatment under drought stress had a reformative effect on the cell cycle (transitions from G0-G1 to S and from S to G2-M), total protein content (almost 100%), endogenous polyamine content, malondialdehyde (MDA) (70%), and ascorbate peroxidase (APX) (62%) levels compared to the drought stress plants. Superoxide dismutase (SOD) (12%) and catalase (CAT) (32%) enzyme levels in the same group increased further after exogenous Put application, forming a response to drought stress. Consequently, it was discovered that the administration of exogenous Put in barley raises endogenous polyamine levels and then improves drought tolerance due to increased antioxidant capability, cell division stimulation, and total protein content.

Polyamines interact with different molecular targets to regulate a vast range of cellular processes. A network of enzymes and transport systems is crucial for the maintenance of polyamine homeostasis. Indeed, polyamines after synthesis must be distributed to the various tissues and some intracellular organelles. Differently from the well characterized enzymes devoted to polyamine synthesis, the transport systems are not unequivocally identified or characterized. Besides some ATPases which have been identified as polyamine transporters, much less is known about solute carriers (SLC) involved in the transport of these compounds. Only two SLCs have been unequivocally identified as polyamine transporters: SLC18B1 (VPAT) and SLC22A4 (OCTN1). Transport studies have been performed with cells transfected with the cDNAs encoding the two and other SLCs or, in the case of OCTN1, also by in vitro assay using proteoliposomes harboring the recombinant human protein. According to the role proposed for OCTN1, polyamines have been associated with prolonged and quality of life. This review provides an update on the most recent findings concerning the polyamine transporters or the prediction of the putative ones.

Chronic obstructive pulmonary disease (COPD) is a highly prevalent chronic respiratory disease characterised by irreversible airways obstruction associated with chronic airways inflammation and remodelling, while the pathogenesis and the mechanistic differences between patients remain to be fully elucidated. We previously reported that alarmin cytokine IL-33 may contribute to the production of autoantibodies against respiratory epithelial cells. Here we expand the hypothesis that pulmonary autoimmune responses induced by airway microbiota also contribute to the progression of COPD. We focused on Edwardsiella tarda which we detected uniquely in the induced sputum of patients with acute exacerbations of COPD. Pernasal challenge of the airways of WT mice with supernatants of cultured E. tarda induced marked, elevated expression of IL-33 in the lung tissues. Immunisation of animals with supernatants of cultured E. tarda resulted in significantly elevated airways inflammation, the formation of tertiary lymphatic structures and significantly elevated proportions of T follicular helper T cells in the lung tissue and mediastinal lymph nodes. Interestingly, such challenge also induced production of IgG autoantibodies directed against lung tissue lysate, alveolar epithelial cell proteins and elastin fragment, while putrescine, one of metabolites generated by the bacterium, might play an important role in the autoantibody production. Furthermore, all of these effects were partly but significantly abrogated in mice with deletion of the IL-33 receptor ST2. Collectively, these data support the hypothesis that COPD is progressed at least partly by airways microbiota such as E. tarda initiating autoimmune attack of the airways epithelium mediated at least partly through the IL-33-ST2 axis.

We studied the effects of some nitrogen-containing, heterocyclic, and cyclic compounds on the rate of oxidative deamination of polyamines and putrescine in tissues with a high proliferation rate. For this purpose, the specific activities of the main enzymes of polyamine oxidative degradation - spermine oxidase (SMO), polyamine oxidase (PAO), and diamine oxidase (DAO) were determined using a cell-free test system from regenerating rat liver. The compounds methyl 2-(5-formylfuran-2-yl)benzoate and 2,7-bis-[2-(diethylamino)ethoxy]-9H-fluoren-9-one (and in the form of dihydrochloride) showed mainly activating effect on oxidative degradation of putrescine, spermidine, and spermine, which indirectly indicates their antiproliferative effect. Nitrogen-free compounds inhibited this process, thus exhibiting potentially carcinogenic properties. Correlations were calculated for activity of DAO, PAO, and SMO with 5 topological indices: Wiener (W), Rouvray (R), Balaban (J) in the Trinaistich modification, detour (Ip), and electropy (Ie). The highest dependence was noted for DAO and the Balaban index (R=-0.55), for PAO and the detour index (R=0.78), and for SMO and the electropy index (R=0.53). The remaining dependencies showed insignificant correlation strength.

BACKGROUND: Polyamines have been reported to be associated with neurological function, but the associations between polyamines and the prognosis of ischemic stroke remain unclear. We aimed to prospectively investigate whether elevated plasma polyamine levels are associated with adverse outcomes in patients with ischemic stroke.
RESULTS: Plasma polyamine levels were measured at admission in 3570 patients with acute ischemic stroke, and clinical outcomes were assessed at 3 months after stroke onset. The primary outcome was a composite outcome of death and major disability (modified Rankin Scale score≥3), and secondary outcomes included the individual outcomes of death and major disability. During a 3-month follow-up period, 877 participants (25.1%) experienced the primary outcome. Increased putrescines were associated with a decreased risk of the primary outcome (the highest versus the lowest tertile: odds ratio, 0.72 [95% CI, 0.58-0.91]; P=0.005) and major disability (odds ratio, 0.59 [95% CI, 0.47-0.74]; P<0.001). Conversely, increased spermidines were associated with an increased risk of death (hazard ratio, 1.86 [95% CI, 1.10-3.14]; P=0.020), and increased spermines were associated with an increased risk of the primary outcome (odds ratio, 1.36 [95% CI, 1.08-1.71]; P=0.009) and major disability (odds ratio, 1.27 [95% CI, 1.01-1.59]; P=0.041).
CONCLUSIONS: Among patients with ischemic stroke, high plasma putrescine levels were associated with a decreased risk of adverse outcomes, whereas high plasma spermidine and spermine levels were associated with an increased risk of adverse outcomes. Further studies are needed to investigate whether targeting these polyamines can improve the prognosis of patients with ischemic stroke.
BACKGROUND: https://clinicaltrials.gov. Identifier: NCT01840072.