Cadaverine Levels Research Articles

Real meat shows good performance in maintaining colonic barrier function at a recommended amount of intake in mice

AbstractThis study aimed to investigate the effects and underlying mechanisms of real meat and plant‐based meat analogs on intestinal barrier function. Methods including PacBio sequencing, HPLC, histological observation, western blotting, and RT‐qPCR were jointly applied. The results indicated that the 20‐day intake of real meat and plant‐based meat analogs did not induce pathological changes in the colon of mice. However, when the feeding period was extended to 68 days, inflammatory infiltration was observed in the colon tissue of mice fed plant‐based meat analogs. In contrast, the intake of real meat for 68 days performed better in maintaining colonic barrier function by reducing cell apoptosis, increasing the number of goblet cells and mucin secretion, and upregulating the expression of tight junction proteins. High‐throughput sequencing revealed that the intake of real meat significantly altered the composition of the gut microbiota, reducing pro‐inflammatory bacteria (such as Bacteroides, Desulfovibrio, or Colidextribacter) or pathogenic bacteria (such as Mucispirillum and Helicobacter) while increasing beneficial bacteria (such as Lactobacillus, Bifidobacterium, or Roseburia). Additionally, the consumption of real meat markedly decreased protein fermentation in the colon, leading to lower levels of cadaverine, putrescine, and spermine. These changes associated with real meat consumption reduced the activation of the pro‐inflammatory pathway (lipopolysaccharide/Toll‐like receptor 4/nuclear factor kappa B), ultimately maintaining colonic homeostasis in mice. Collectively, the findings suggest that the proper intake of real meat is more beneficial for colon health in mice compared to plant‐based meat analogs.

Effects of Inoculating Autochthonous Starter Cultures on Changes of N-Nitrosamines and Their Precursors in Chinese Traditional Fermented Fish during In Vitro Human Digestion.

The objective of this research was to investigate the impact of inoculating autochthonous starter cultures on the alterations in microorganisms, biogenic amines, nitrite, and N-nitrosamines in Chinese traditional fermented fish products (CTFPs) during in vitro human digestion. The results revealed that gastric digestion significantly (p < 0.05) inhibited the proliferation of lactic acid bacteria, yeast, Staphylococcus, and Enterobacteriaceae, whereas various microorganisms proliferated extensively during small intestine digestion. Meanwhile, small intestine digestion could significantly increase (p < 0.05) levels of putrescine, cadaverine, and tyramine. The reduced content observed in inoculated fermentation groups suggests that starter cultures may have the ability to deplete biogenic amines in this digestion stage. Gastric digestion significantly (p < 0.05) inhibited nitrite accumulation in all CTFPs samples. Conversely, the nitrite content increased significantly (p < 0.05) in all groups during subsequent small intestine digestion. However, the rise in the inoculated fermentation groups was smaller than that observed in the spontaneous fermentation group, indicating a potentially positive role of inoculated fermentation in inhibiting nitrite accumulation during this phase. Additionally, gastric digestion significantly (p < 0.05) elevated the levels of N-nitrosodimethylamine (NDMA) and N-nitrosopiperidine in CTFPs. Inoculation with L. plantarum 120, S. cerevisiae 2018, and mixed starter cultures (L. plantarum 120, S. cerevisiae 2018, and S. xylosus 135 [1:1:1]) effectively increased the degree of depletion of NDMA during this digestion process.

Combined assessment of lysine and N-acetyl cadaverine levels assist as a potential biomarker of the smoker periodontitis

Periodontitis is an inflammatory condition of supporting structures of teeth leading to attachment and bone loss. Cigarette smoking is the single most important and modifiable risk factor with 5 to 20-fold susceptibility for periodontal diseases. Reverse smoking is a peculiar habit of smoking where the lit end is kept inside the mouth, which is predominant in the northern coastal districts of Andhra Pradesh. Polyamines are biologically active amines involved in tissue regeneration and modulation of inflammation. The study aimed to evaluate polyamines and check their utility as a marker in detection of periodontitis among different groups. Total polyamine levels showed significant increase in reverse smokers with periodontitis when compared to the other groups. Qualitative analysis by thin layer chromatography showed three polyamine bands with varying intensity among the different groups. Mass spectrometric and NMR analyses of the three bands identified them as N1, N8-diacetyl spermidine, N-acetyl cadaverine and lysine. Most significantly elevated levels of lysine was observed in the smoker and reverse smoker periodontitis groups when compared to healthy and non-smoker periodontitis groups. The significantly elevated levels of N-acetyl cadaverine could be responsible for the more destruction of periodontium in the reverse smoker group. Antioxidant potential decreased significantly in different smoker periodontitis groups. The present study suggests that the quantitative analysis of salivary polyamines, lysine and N-acetyl cadaverine can aid as an easy noninvasive diagnostic method for assessing the periodontal status, especially in smokers.

Combining directed evolution with high cell permeability for high-level cadaverine production in engineered Escherichia coli.

The biosynthesis of cadaverine from lysine is an environmentally promising technology, that could contribute to a more sustainable approach to manufacturing bio-nylon 5X. However, the titer of biosynthesized cadaverine has still not reached a sufficient level for industrial production. A powerful green cell factory was developed to enhance cadaverine production by regulating lipopolysaccharide (LPS) genes and improving membrane permeability. Firstly, 10 LPS mutant strains were constructed and the effect on the growth was investigated. Then, the lysine decarboxylase (CadA) was overexpressed in 10 LPS mutant strains of Escherichia coli MG1655 and the ability to produce cadaverine was compared. Using 20.0gL-1 of L-lysine hydrochloride (L-lysine-HCl) as the substrate for the biotransformation reaction, Cad02 and Cad06 strains exhibited high production levels of cadaverine, with 8.95gL-1 and 7.55gL-1 respectively while the control strain Cad00 only 4.92gL-1 . Directed evolution of CadA was also used to improve its stability under alkaline conditions. The cadaverine production of the Cad02-M mutant stain increased by 1.86 times at pH 8.0. Finally, the production process was scaled up using recombinant whole cells as catalysts, achieving a high titer of 211gL-1 cadaverine (96.8%) by fed-batch bioconversion. This study demonstrates the potential role of LPS in enhancing the efficiency of mass transfer between substrate and enzymes in vivo by increasing cell permeability. The results indicate that the argumentation of cell permeability could not only significantly enhance the biotransformation efficiency of cadaverine, but also provide a universally applicable, straightforward, environment-friendly, and cost-effective method for the biosynthesis of other high-value chemicals.

Effects of the physical structure and surface charge of activated carbon on the reduction of biogenic amines in anchovy fish sauce

This study aimed to efficiently reduce a large number of biogenic amines in salt-fermented fish sauce while minimizing sensory reduction using various activated carbons. Aromatic amines, such as tryptamine and phenethylamine, were reduced by 86.1–100 % after treating with activated carbon. Histamine with a heterocyclic structure decreased by 13–42 %. No significant effects were observed on the levels of aliphatic amines, putrescine, cadaverine, spermine, and spermidine. The major taste component, amino acid nitrogen, was reduced to within 3 %, and brown color removal was reduced depending on the type of activated carbon used. Acid-modified AC-A and AC-B had rough surfaces, high total acidity, low point of zero charge (pHpzc), and rich surface functional groups. Owing to its smooth surface, low total acidity, high pHpzc, and few surface functional groups, AC-C exhibited a higher histamine elimination and less color reduction despite its lower surface area compared to other activated carbons.

Cadaverine as a Potential Spoilage Indicator in Skin-Packed Beef and Modified-Atmosphere-Packed Beef.

This study investigated cadaverine as a spoilage indicator in commercial beef products stored under conditions favourable for the growth of lactic acid bacteria. Samples included vacuum-skin-packed entrecotes (EB) aged up to 42 days and modified-atmosphere-packed (70% O2 + 30% CO2) minced beef (MB) stored at 5 °C. Two MB product lines were analysed: one stored aerobically two days post-slaughter before mincing and another stored for 14 days in vacuum packaging prior to mincing. Sensory assessment/evaluation and microbial analysis were performed throughout the shelf life of the products and compared to cadaverine levels measured using LC-MS/MS. Cadaverine concentrations in EB reached approximately 40,000 µg/kg on the "best before" date, while remaining below 50 µg/kg in both MB products on the corresponding date. While cadaverine concentrations in EB displayed a consistent increase, suggesting its potential as a spoilage indicator post-ageing, the low concentrations in MB, did not correlate with sensory assessments, revealing its limitations as a universal spoilage marker. In conclusion, it is necessary to conduct product-specific studies to evaluate the applicability of cadaverine as a spoilage indicator for beef products.

Assessment of biogenic amines in commercial tuna fish: Influence of species, capture method, and processing on quality and safety

This study investigated the influence of species, capture method, chilling, and freezing on the quality and variations in biogenic amines of Thunnus tonggol and Thunnus albacares. Samples were collected from different sources, including fisheries ports, cold rooms, and canning factories. The results indicated that canned fish had significantly higher levels of biogenic amines, especially histamine, compared to raw fish from ports and cold rooms. However, all canned samples complied with the FDA regulation of 50 mg/kg for histamine content. Canning led to a substantial increase in total amines, with histamine being the predominant amine in most groups. Putrescine was present in all samples, with the highest levels found in canned tuna made from frozen yellow-fin tuna captured using drift gillnetting. Canned samples also exhibited higher cadaverine levels compared to raw tuna. Storage conditions, capture method, and tuna species were found to significantly affect tuna quality and biogenic amines formation.

Effect of the Probiotic Bacillus subtilis DE-CA9TM on Fecal Scores, Serum Oxidative Stress Markers and Fecal and Serum Metabolome in Healthy Dogs.

There is increasing interest in the use of Bacillus species as probiotics since their spore-forming ability favors their survival in the acidic gastric environment over other probiotic species. The subsequent germination of B. subtilis to their vegetative form allows for their growth in the small intestine and may increase their beneficial effect on the host. B. subtilis strains have also previously been shown to have beneficial effects in humans and production animals, however, no reports are available so far on their use in companion animals. The goal of this study was therefore to investigate the daily administration of 1 × 109 cfu DE-CA9TM orally per day versus placebo on health parameters, fecal scores, fecal microbiome, fecal metabolomics, as well as serum metabolomics and oxidative stress markers in ten healthy Beagle dogs in a parallel, randomized, prospective, placebo-controlled design over a period of 45 days. DE-CA9TM decreased the oxidative status compared to controls for advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances (TBARS) and reactive oxygen metabolites (d-ROMS), suggesting an antioxidant effect of the treatment. Fecal metabolomics revealed a significant reduction in metabolites associated with tryptophan metabolism in the DE-CA9TM-treated group. DE-CA9TM also significantly decreased phenylalanine and homocysteine and increased homoserine and threonine levels. Amino acid metabolism was also affected in the serum metabolome, with increased levels of urea and cadaverine, and reductions in N-acetylornithine in DE-CA9TM compared to controls. Similarly, changes in essential amino acids were observed, with a significant increase in tryptophan and lysine levels and a decrease in homocysteine. An increase in serum guanine and deoxyuridine was also detected, with a decrease in beta-alanine in the animals that ingested DE-CA9TM. Data generated throughout this study suggest that the daily administration of 1 × 109 cfu of DE-CA9TM in healthy Beagle dogs is safe and does not affect markers of general health and fecal scores. Furthermore, DE-CA9TM administration had a potential positive effect on some serum markers of oxidative stress, and protein and lipid metabolism in serum and feces.

Evaluating biogenic amines and pH levels in farmed rainbow trout (Oncorhynchus mykiss) for freshness assessment during storage

This study examined the production of eight key biogenic amines (methylamine, tryptamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine) in 120 samples of farmed rainbow trout during various storage conditions, and determined any accompanying variations in pH. The main objective of this study was to identify which of the eight biogenic amines could be used as chemical markers to evaluate the quality of farmed rainbow trout. Histamine and tryptamine were not present in any of the samples, and the levels of cadaverine were inconsistent. The levels of putrescine significantly increased at 0 °C (by day 9), 2 °C (by day 8), and 4 °C (by day 4). Tyramine, spermidine, and spermine levels exhibited fluctuations but had a significant positive correlation with the levels of putrescine. The pH levels slightly increased from their initial values across all storage temperatures, with no significant variations observed. Based on the results, it can be concluded that putrescine may serve as an effective marker of the freshness of farmed rainbow trout during storage.

Non-aminobiogenic starter cultures in a model system of cucumber fermentation

Liquid chromatography–mass spectrometry and 16S rDNA amplicon sequencing were applied for assessing the biogenic amine (BA) content and bacterial community profile in a model system of cucumber fermentation. The non-aminobiogenic strains Lacticaseibacillus casei KKP 3272 and Pediococcus pentosaceus KKP 3273 were used individually as starter cultures. The Biogenic Amine Index (BAI) was effectively reduced by both tested strains compared with that in the spontaneously fermented samples. After 6 months of storage, BAI was reduced by 78.18 and 90.12% following fermentation by L. casei and P. pentosaceus, respectively. Histamine and putrescine were reduced by over 90% regardless of the starter culture used, while P. pentosaceus KKP 3273 was more effective for reducing tyramine and cadaverine levels (96% and 51% decrease, respectively). Detailed analysis revealed that the bacterial community profile of the samples depended on the strain applied and number of inoculated cells. Addition of 107 CFU⋅mL−1P. pentosaceus KKP 3273 or L. casei KKP 3272 resulted in their predominance in the samples after storage (93.03% and 78.62%, respectively). In spontaneously fermented samples, Enterobacter (35.21%), Lactobacillus (22.41%), and Pediococcus (20.40%) prevailed. The application of an appropriate amount of well-characterised starter culture can effectively prevent the formation of high amounts of BAs and provide a safer product.

Dysbiosis of Oral Microbiota and Metabolite Profiles Associated with Type 2 Diabetes Mellitus.

Several previous studies have shown that oral microbial disorders may be closely related to the occurrence and development of type 2 diabetes mellitus (T2DM). However, whether the function of oral microorganisms and their metabolites have changed in patients with T2DM who have not suffered from any oral diseases has not been reported. We performed metagenomic analyses and nontargeted metabolic analysis of saliva and supragingival plaque samples from patients with T2DM who have not suffered any oral diseases and normal controls. We found that periodontal pathogens such as Porphyromonas gingivalis and Prevotella melaninogenica were significantly enriched, while the abundances of dental caries pathogens such as Streptococcus mutans and Streptococcus sobrinus were not significantly different in patients with T2DM compared to those in normal controls. Metabolomic analyses showed that the salivary levels of cadaverine and L-(+)-leucine of patients with T2DM were significantly higher than those of normal controls, while the supragingival plaque levels of N-acetyldopamine and 3,4-dimethylbenzoic acid in patients with T2DM were significantly higher than those in the normal controls. Additionally, we identified the types of oral microorganisms related to the changes in the levels of circulating metabolites, and the oral microorganisms were involved in the dysregulation of harmful metabolites such as cadaverine and n, n-dimethylarginine. Overall, our study first described the changes in the composition of oral microorganisms and their metabolites in patients with T2DM who have not suffered any oral diseases, which will provide a direct basis for finding oral biomarkers for early warning of oral diseases in T2DM. IMPORTANCE The incidence of oral diseases in type 2 diabetic patients might increase, and the severity might also be more serious. At present, the relationship between oral microorganisms and type 2 diabetes mellitus (T2DM) has become a hot topic in systemic health research. However, whether the function of oral microorganisms and their metabolites have changed in patients with T2DM who have not suffered from any oral diseases has not been reported. We found that even if the oral condition of T2DM is healthy, their oral microbes and metabolites have changed, thus increasing the risk of periodontal disease. Our study first described the changes in the composition of oral microorganisms and their metabolites in T2DM who have not suffered any oral diseases and revealed the correlation between oral microorganisms and their metabolites, which will provide a direct basis for finding oral biomarkers for early warning of oral diseases in patients with T2DM.

Torquetenovirus in pregnancy: Correlation with vaginal microbiome, metabolome and pro-inflammatory cytokines.

Torquetenovirus (TTV) is a negative sense, single-stranded DNA virus present in many body fluids of apparently healthy individuals. At present, it is considered a non-pathogenic endogenous virus. TTV can be detected in the vagina of pregnant women, its abundance being modulated with the extent of immune system activation. Until now, there is only scarce information regarding the association between TTV and the composition of the vaginal environment. Therefore, this study aimed to assess the presence of TTV in the vaginal ecosystem of a cohort of white women with a normal pregnancy (n = 60) at different gestational stages (first, second and third trimester) and in 9 subjects suffering a first trimester miscarriage. For each woman, we determined (i) the presence and titer of TTV, (ii) the vaginal bacterial composition by means of Nugent score and 16S rRNA gene sequencing, (iii) the vaginal metabolic profiles through 1H-NMR spectroscopy, and (iv) the vaginal concentration of two pro-inflammatory cytokines (IL-6 and IL-8). More than one third of women were found negative for TTV at all gestational stages. Although not statistically significant, the positivity for TTV dropped from 53.3% in the first to 36.6% in the third trimester. TTV loads varied greatly among vaginal samples, ranging between 2 × 101 and 2 × 105 copies/reaction. No difference in TTV prevalence and loads was observed between women with normal pregnancies and miscarriages. The presence of TTV was more common in women with a higher vaginal leucocyte count (p = 0.02). The levels of IL-6 (p = 0.02), IL-8 (p = 0.03), propionate (p = 0.001) and cadaverine (p = 0.006) were significantly higher in TTV-positive samples. TTV titer was positively correlated with the concentrations of 4-hydroxyphenyllactate (p < 0.0001), isoleucine (p = 0.01) and phenylalanine (p = 0.04). TTV-positive samples were characterized by a higher relative abundance of Sneathia (p = 0.04) and Shuttleworthia (p = 0.0009). In addition, a trend toward a decrease of Lactobacillus crispatus and Lactobacillus jensenii, and an increase of Lactobacillus iners was observed for TTV-positive samples. In conclusion, we found that TTV is quite common in women with normal pregnancy outcomes, representing a possible predictor of local immune status.

Identification of active compounds in Ophiopogonis Radix from different geographical origins by UPLC-Q/TOF-MS combined with GC-MS approaches

Ophiopogonis Radix, also known as Maidong in Chinese, is largely produced in the Sichuan and Zhejiang provinces: “Chuan-maidong (CMD)” and “Zhe-maidong (ZMD),” respectively. This study aimed to distinguish and evaluate the quality of CMD and ZMD. In this study, the tubers of CMD and ZMD were investigated using UPLC-Q/TOF-MS, GC-MS, and LC-MS methods, respectively. Overall, steroidal saponins, homoisoflavonoids, amino acids, and nucleosides were quickly identified. Furthermore, multivariate statistical analysis revealed that CMD and ZMD could be separated. Moreover, CMD showed higher levels of 4-aminobutanoic acid, glycine, l-proline, monoethanolamine, and serine than ZMD. Besides, the levels of chlorogenic acid, traumatic acid, cytidine, cadaverine, pyridoxine 5-phosphate, glutinone, and pelargonidin 3-O-(6-O-malonyl-β-d-glucoside) were remarkably higher in ZMD than in CMD. Furthermore, these different constituents were mainly associated with galactose metabolism; starch and sucrose metabolism; cysteine and methionine metabolism; valine, leucine, and isoleucine biosynthesis; and glycerophospholipid metabolism. In general, these results showed many differences between the bioactive chemical constituents of Ophiopogon japonicus from different production areas, where ZMD performed better in the quality assessment than CMD, and that UPLC-Q/TOF-MS, GC-MS, and LC-MS are effective methods to discriminate medicinal herbs from different production areas.

Maternal probiotics supplementation improves immune and antioxidant function in suckling piglets via modifying gut microbiota.

Probiotics could improve the health, growth, and development of host or their foetuses/offspring via regulating gut microbiota. The present study was conducted to determine the effects of maternal probiotics supplementation on gut microbiota and metabolites of sows and their suckling piglets, as well as plasma biochemical parameters, oxidative/anti-oxidative indexes, and inflammatory cytokine levels of suckling piglets. A total of 32 pregnant Bama mini-pigs were selected and randomly divided into two groups. The sows were fed a basal diet (control group) or a basal diet supplemented with probiotics (probiotics group) from mating to day 21 of lactation. Samples from sows were collected on day 105 of pregnancy and day 21 of lactation and from piglets on day 21 of lactation. The results showed that probiotics supplementation increased the faecal abundances of Ruminococcus, Bacteroides, and Anaeroplasma and decreased Tenericutes on day 105 of pregnancy while increased the abundances of Actinobacteria and Anaerostipes and decreased Proteobacteria and Desulfovibrio on day 21 of lactation. In addition, probiotics supplementation decreased the faecal levels of tryptamine, putrescine, and cadaverine on day 105 of pregnancy and isovalerate and skatole on day 21 of lactation while increased butyrate level on day 21 of lactation. Further studies showed that maternal probiotics supplementation decreased the plasma levels of AMM, TC, LDL-C, Ala, Tau, MDA, H2 O2 , IL-1β, IL-2, IL-6, and IFN-α of suckling piglets. Moreover, maternal probiotics supplementation increased the abundances of Deferribacteres, Fusobacteria, and Fusobacterium while decreased Anaerostipes in piglet's colon. Spearman's correlation analysis revealed a potential link between gut microbiota alterations and their metabolites. Dietary probiotics supplementation during pregnancy and lactation periods could improve sow status, alleviate oxidative stress and inflammation response, and improve nutrient metabolism of piglets by altering the gut microbiota. The probiotics alter maternal and offspring's gut microbiota involving in offspring's physiological and metabolic changes, and present a new perspective that the effects of gut microbiota changes induced by probiotics supplementation will help in addressing the growth and development and health problem of their foetuses/offspring.

Novel cadaverine non-invasive biosensor technology for the prediction of shelf life of modified atmosphere packed pork cutlets

Food waste in perishable products calls for the development of cost-efficient and real-time freshness and shelf life assessment tools. The current study evaluated a newly developed cadaverine biosensor for its ability to assess the sensory freshness stage and microbial quality of modified atmosphere packed (MAP) pork cutlets under a realistic supply chain scenario.The experiment compared the cadaverine levels measured by the biosensor to liquid chromatography - tandem mass spectrometry (LC-MS/MS) cadaverine concentrations, and associated these to the shelf life estimation and freshness states determined by sensory and microbial evaluations during an 18-day storage period (5 °C).Results underlined the potential of cadaverine as a freshness biomarker as well as the applicability of the biosensor as a shelf life prediction tool. This is supported by the correlations obtained between sensory odour freshness evaluation and total viable counts with biosensor cadaverine levels for which the r obtained were 0.97 (<0.001) and 0.95 (<0.001), respectively.

Effects of frying and baking processing conditions changes on biogenic amines and volatile components in Jumbo squid (Dosidicus gigas)

This study aimed to investigate the effect of temperature and time changes in two typical thermal processing procedures, frying and baking, on squid quality. Increasing the frying/baking temperature and prolonging the time significantly impacted color, L* value decreased over time, and a* value increased (P < 0.05). Total nitrogen, non-protein nitrogen, and cadaverine levels increased significantly after thermal process (P < 0.05), whereas histamine levels increased and subsequently reduced, which was attributed to the process of lipid oxidation. The concentration of pyrazine was dramatically increased (fried: 3.01 ∼ 1468.27 µg/kg; baked: 0.00 ∼ 836.14 µg/kg). The hierarchical cluster analysis was applied to analyze the complicated raw data of squid in order to evaluate the quality under different frying/baking conditions. Squid, whether fried or baked, took on a deeper color, contained more protein per unit weight, and tasted more desirable, although the histamine levels rose at certain temperatures as well. This study indicated the appropriate cooking methods and conditions could help to preserve nutrition while keeping histamine levels under control.

The Host CYP1A1-Microbiota Metabolic Axis Promotes Gut Barrier Disruption in Methicillin-Resistant Staphylococcus aureus-Induced Abdominal Sepsis.

BackgroundHost-microbiota crosstalk has been implicated in multiple host metabolic pathway axes that regulate intestinal barrier function. Although constitutive cytochrome P4501A1 (CYP1A1) expression perturbs the microbiome-derived autoregulatory loop following enteric infection, little is known about the role of host CYP1A1 in modulating gut microbiome-mediated signaling during methicillin-resistant Staphylococcus aureus (MRSA)-induced abdominal sepsis and its effects on intestinal barrier integrity.MethodsAbdominal sepsis was induced by the intraperitoneal injection of MRSA in mice. The effect of CYP1A1 deficiency on gut barrier integrity was investigated using RNA sequencing, microbiome analyses, and targeted metabolomics. The microbiota-produced metabolites were validated in patients with sepsis and persistent MRSA infection.ResultsMice lacking CYP1A1 exhibited an altered gut microbiome, a reduced metabolic shift from lysine to cadaverine in the caecal contents and antimicrobial molecule production (Retnlb, Gbp7, and Gbp3), and they were protected against gut barrier disruption when subjected to MRSA challenge. These beneficial effects were validated in aryl hydrocarbon receptor (AHR) knockout (KO) mice by cohousing with CYP1A1 KO mice and abrogated after supplementation with cadaverine or Enterococcus faecalis, the primary microbiota genus for cadaverine synthesis. Antibiotic-driven gut dysbacteriosis impaired the survival benefit and disrupted the intestinal barrier integrity in CYP1A1 KO mice after MRSA infection. Furthermore, increased cadaverine levels in feces and serum were detected in critically ill patients with gut leakiness during persistent MRSA infection, whereas cadaverine was not detected in healthy controls. Additionally, microbiota-derived cadaverine induced enterocyte junction disruption by activating the histamine H4 receptor/nuclear factor-κB/myosin light-chain kinase signaling pathway.ConclusionThis study revealed the unexpected function of host CYP1A1 in microbiota-mediated cadaverine metabolism, with crucial consequences for dysbacteriosis following MRSA-induced abdominal sepsis, indicating that inhibiting CYP1A1 or blocking cadaverine-histamine H4 receptor signaling could be a potential therapeutic target against abdominal sepsis.Clinical Trial Registration[http://www.chictr.org.cn/index.aspx], identifier [ChiCTR1800018646].

Investigation of salivary biomarkers as indicators of skeletal and dental maturity in children.

Estimation of patient's skeletal maturity in orthodontics is essential for the diagnosis and treatment planning. The aim of the study was to investigate the potential use of metabolic fingerprint of saliva for bone growth and tooth development estimation. Saliva samples from 54 young patients were analysed by an untargeted gas chromatography-mass spectrometry metabolomics-based method. The skeletal maturity was calculated with the cervical vertebrae maturation method, and the dental age was estimated with the Demirjian method. Multivariate analysis and univariate analysis were performed to investigate differences within skeletal, dental and chronological age groups. Metabolomic analysis identified 61 endogenous compounds. Mannose, glucose, glycerol, glyceric acid and pyroglutamic acid levels differentiated significantly with skeletal age (P=.02 to .043), while mannose, lactic acid, glycolic acid, proline, norleucine, 3-aminoisobutyric acid, threonine, cadaverine and hydrocinnamic acid levels differed within the dental age groups (P=.018 to .04); according to the chronological age, only the levels of mannose and 3-hydroxyphenylacetic acid showed variation (P=.029 and .048). The principal component analysis did not manage to highlight differences between the groups of the studied parameters. Differentiated levels of mannose, glucose, glycerol, glyceric acid and pyroglutamic acid related to skeletal maturation were identified. According to dental development, the levels of mannose, lactic acid, glycolic acid, proline, norleucine, 3-aminoisobutyric acid, threonine, cadaverine and hydrocinnamic acid differed within the groups, while regarding chronological age, only the levels of mannose and 3-hydroxyphenylacetic acid showed variations. Further studies are required to prove their relation to skeletal and dental development pathway by applying complementary analytical techniques to wider cover the metabolome.

Effect of Mixed Starters on Proteolysis and Formation of Biogenic Amines in Dry Fermented Mutton Sausages.

In this study, by comparing the four groups of sausages, namely, CO (without starter culture), LB (with Lactobacillus sakei), LS (with L. sakei 3X-2B + Staphylococcus xylosus SZ-8), and LSS (with L. sakei 3X-2B + S. xylosus SZ-8 + S. carnosus SZ-2), the effects of mixed starter cultures on physical–chemical quality, proteolysis, and biogenic amines (BAs) during fermentation and ripening were investigated. Inoculation of the mixed starter cultures increased the number of lactic acid bacteria and staphylococci in sausages during fermentation and ripening for 0 to 5 days. The L. sakei 3X-2B + S. xylosus SZ-8 + S. carnosus SZ-2 mixed starter accelerated the rate of acid production and water activity reduction of sausages and improved the redness value. Compared with CO, the mixed starter effectively inhibited Enterobacteriaceae. At the end of ripening, the LSS group was approximately 1.25 CFU/g, which was less than the CO group, thereby reducing the total volatile basic nitrogen (TVB-N) in the LSS group. The free amino acids in the LS and LSS groups (224.97 and 235.53 mg/kg dry sausage, respectively) were significantly (p < 0.001) higher than that in the CO group (170.93 mg/kg dry sausage). The level of histamine, cadaverine, putrescine, and common BAs showed an opposite trend to the increase of the corresponding precursor amino acid content, which were significantly lower (p < 0.001) in the LS and LSS sausages than in CO. This study showed that L. sakei 3X-2B + S. xylosus SZ-8 + S. carnosus SZ-2 is a potential mixed starter for fermented meat products.

Effect of a compound starter cultures inoculation on bacterial profile and biogenic amine accumulation in Chinese Sichuan sausages

Effects of a starter culture composed of Lactobacillus sakei, Pediococcus pentosaceus, Staphylococcus xylosus and S. carnosus at the ratios (m/m) of 1:1:1:1 on bacterial profile and biogenic amine accumulation in Chinese Sichuan sausages were demonstrated. In starter culture-inoculated sausages, Lactobacillus spp., Pediococcus spp. and Staphylococcus spp. were predominant bacterial genus and their relative abundances ranged from 70.14% to 25.98%, 57.66% to 14.08%, and 15.71% to 13.40% during fermentation, respectively. Accordingly, Lactobacillus spp. and Weissella spp. were predominant bacterial genus and their relative abundances ranged from 63.14% to 24.70% and 49.40% to 11.96% during spontaneous fermentation, respectively. Furthermore, the abundances of undesirable microorganisms such as Yersinia spp., Enterobacter spp., Acietobacter spp. and Psychrobacter spp. were lower than that of the control. The levels of histamine, putrescine, tyramine and cadaverine in Chinese Sichuan sausages with starter cultures inoculation were significantly lower (P<0.05) than that of the control, and were decreased by 83.09%, 69.38%, 51.87% and 57.20%, respectively, at the end of the ripening. These results revealed that the starter cultures inoculation was a better alternative for microbial quality improvement and biogenic amine reduction of Chinese Sichuan sausages with good sensory attributes.