54 research outputs found

    Lipidomics for Determining Giant Panda Responses in Serum and Feces Following Exposure to Different Amount of Bamboo Shoot Consumption: A First Step towards Lipidomic Atlas of Bamboo, Giant Panda Serum and Feces by Means of GC-MS and UHPLC-HRMS/MS

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    Lipidic metabolites play essential roles in host physiological health and growth performance, serving as the major structural and signaling components of membranes, energy storage molecules, and steroid hormones. Bamboo, as wild giant pandas' exclusive diet, is the main determinant of giant pandas' lipidome, both as a direct source and through microbiota activity. Interestingly, the consumption of bamboo has attracted little attention from a lipidomic perspective. In the current study, we outline the lipidomic atlas of different parts of bamboo. By gas chromatography-mass spectrometry (GC-MS), we have been able to obtain the absolute quantification of 35 fatty acids pertaining to short chain fatty acids (8), medium chain fatty acids (6), long chain fatty acids (17), and very long chain fatty acids (4), while liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS) allowed us to obtain the relative quantification of another 1638 lipids. Among the fatty acids quantified in absolute terms, eight showed significantly distinct concentrations among different bamboo parts. Subsequently, we investigated how the giant panda's serum and fecal lipidome adapt to the most important annual change in their diet, represented by the consumption of high amounts of bamboo shoots, typical of spring, the weight-gaining season. Five fatty acids were significantly altered in feces and two in serum, respectively, due to the different levels of bamboo shoot consumption. Furthermore, significant differences of the main bacteria strains were observed in feces between the two groups at the genus level, pertaining to Streptococcus, Leuconostoc, and Vagococcus. Correlations between giant panda fecal microbiome and lipidome were evaluated by Pearson correlation analysis. These findings suggest that a balanced diet, important for the overall lipidomic function and giant panda health, could be reached even in this remarkable case of a single food-based diet, by administering to the giant panda's combinations of different parts of bamboo, with specific lipidome profiles

    Investigation of diverse bacteria encoding histidine decarboxylase gene in Sichuan-style sausages by culture-dependent techniques, polymerase chain reaction-denaturing gradient gel electrophoresis, and high-throughput sequencing

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    The diverse bacteria encoding histidine decarboxylase gene during the fermentation of Sichuan-style sausages were investigated by culture-dependent techniques, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), and high-throughput sequencing. All microbial indicators exhibited the advantages of mixed starter culture and the stability of microecosystem was more in the inoculation group than in the control group. DGGE and selected band sequencing were used to investigate the bacterial diversity of these sausages. Weissella were the main lactic acid bacteria (LAB) in the initial fermentation stage, whereas Weissella and Lactobacillus were the dominant bacteria in the later fermentation stage. After sequence alignment analysis, Enterobacter aerogenes and Citrobacter freundi were the two main bacteria encoding histidine decarboxylase gene and could produce histamine. These findings facilitate the better understanding of bacteria producing histidine decarboxylase during sausage fermentation and provide a theoretical basis for the control of histamine-producing bacteria in the process of fermented sausage processing.Peer reviewe

    Antibiotic and disinfectant resistance of Salmonella enterica Typhimurium

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    Objective The aims of this study were to investigate the antibiotic resistance, disinfectant resistance and their associations in 302 Salmonella enterica Typhimurium (S. Typhimurium) isolates from retail meats, food animals and humans. Methods Antibiotic susceptibility testing was performed according to the Kirby-Bauer disk diffusion method. The minimal inhibitory concentrations (MICs) of disinfectants were determined by broth microdilution method, and disinfectant resistance genes were detected by polymerase chain reaction (PCR) amplification. Results Antibiotic susceptibility testing demonstrated that 96.03% (290/302) of S. Typhimurium isolates were resistant to at least one antibiotic and 79.80% (241/302) were multidrug resistant (MDR). Tested isolates showed the highest resistance to streptomycin (78.81%, 238/302), followed by compound sulphonamides (78.15%, 236/302), tetracycline (75.50%, 228/302) and ampicillin (71.85%, 217/302). All isolates were sensitive to cefepime and imipenem. The resistance of S. Typhimurium from food to compound sulphonamides, tetracycline, ampicillin, nalidixic acid, and gentamicin were significantly higher than those from human and animal origin (P1 024 mg/L, respectively. In addition, the frequency of resistance to PVP-I, BC and TCS was observed significantly higher in food and animal isolates than human isolates (P<0.05). The qacEΔ1, sugE (p) and qacE disinfectant resistance genes were detected in 56.95% (172/302), 20.53% (62/302) and 2.65% (8/302) of all the isolates, respectively. Notably, qacEΔ1 gene was significantly associated with β-lactam, aminoglycoside, tetracycline, sulfonamide, quinolone and chloramphenicol resistance (P<0.01). Conclusion It was indicated that antibiotic and disinfectant resistance were common among S. Typhimurium isolates and the use of disinfectants or antibiotics may contribute to co-selecting isolates with acquired resistance to other antimicrobials, which could pose significant threats to food safety and public health

    Effects of lipids with different oxidation levels on protein degradation and biogenic amines formation in Sichuan-style sausages

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    ABS T R A C T We evaluated the effects of different oxidation levels of lipids on protein degradation and biogenic amines (BAs) formation during Sichuan-style sausages processing. Lipids with varying degrees of oxidation were obtained through storage at different temperatures and added as raw materials of Sichuan-style sausages, followed by the analyses of lipid oxidation, protein degradation, biogenic amine content, and other indicators. During the pro-cessing, with increasing degree of lipid oxidation, the contents of peroxide value (POV), thiobarbituric acid reactive substances (TBARs), protein degradation index (PI), amino acid nitrogen (AAN), free amino acids (FAAs), and BAs increased. Based on the protein electrophoresis results, the higher the oxidation degree of pig backfat, the higher degree of sarcoplasmic protein oxidation, and the greater myofibril protein degradation. Pearson correlation revealed that lipid oxidation, protein degradation, and BAs content correlated significantly (P < 0.05).Peer reviewe

    Study on diversity, nitrogen-fixing capacity, and heavy metal tolerance of culturable Pongamia pinnata rhizobia in the vanadium-titanium magnetite tailings

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    IntroductionThe diversity, nitrogen-fixing capacity and heavy metal tolerance of culturable rhizobia in symbiotic relationship with Pongamia pinnata surviving in vanadium (V) - titanium (Ti) magnetite (VTM) tailings is still unknown, and the rhizobia isolates from the extreme barren VTM tailings contaminated with a variety of metals would provide available rhizobia resources for bioremediation.MethodsP. pinnata plants were cultivated in pots containing the VTM tailings until root nodules formed, and then culturable rhizobia were isolated from root nodules. The diversity, nitrogen-fixing capacity and heavy metal tolerance of rhizobia were performed.ResultsAmong 57 rhizobia isolated from these nodules, only twenty strains showed different levels of tolerance to copper (Cu), nickel (Ni), manganese (Mn) and zinc (Zn), especially strains PP1 and PP76 showing high tolerance against these four heavy metals. Based on the phylogenetic analysis of 16S rRNA and four house-keeping genes (atpD, recA, rpoB, glnII), twelve isolates were identified as Bradyrhizobium pachyrhizi, four as Ochrobactrum anthropic, three as Rhizobium selenitireducens and one as Rhizobium pisi. Some rhizobia isolates showed a high nitrogen-fixing capacity and promoted P. pinnata growth by increasing nitrogen content by 10%-145% in aboveground plant part and 13%-79% in the root. R. pachyrhizi PP1 showed the strongest capacity of nitrogen fixation, plant growth promotion and resistance to heavy metals, which provided effective rhizobia strains for bioremediation of VTM tailings or other contaminated soils. This study demonstrated that there are at least three genera of culturable rhizobia in symbiosis with P. pinnata in VTM tailings.DiscussionAbundant culturable rhizobia with the capacity of nitrogen fixation, plant growth promotion and resistance to heavy metals survived in VTM tailings, indicating more valuable functional microbes could be isolated from extreme soil environments such as VTM tailings

    Metagenomic Analysis of Bacteria, Fungi, Bacteriophages, and Helminths in the Gut of Giant Pandas

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    To obtain full details of gut microbiota, including bacteria, fungi, bacteriophages, and helminths, in giant pandas (GPs), we created a comprehensive microbial genome database and used metagenomic sequences to align against the database. We delineated a detailed and different gut microbiota structures of GPs. A total of 680 species of bacteria, 198 fungi, 185 bacteriophages, and 45 helminths were found. Compared with 16S rRNA sequencing, the dominant bacterium phyla not only included Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria but also Cyanobacteria and other eight phyla. Aside from Ascomycota, Basidiomycota, and Glomeromycota, Mucoromycota, and Microsporidia were the dominant fungi phyla. The bacteriophages were predominantly dsDNA Myoviridae, Siphoviridae, Podoviridae, ssDNA Inoviridae, and Microviridae. For helminths, phylum Nematoda was the dominant. In addition to previously described parasites, another 44 species of helminths were found in GPs. Also, differences in abundance of microbiota were found between the captive, semiwild, and wild GPs. A total of 1,739 genes encoding cellulase, β-glucosidase, and cellulose β-1,4-cellobiosidase were responsible for the metabolism of cellulose, and 128,707 putative glycoside hydrolase genes were found in bacteria/fungi. Taken together, the results indicated not only bacteria but also fungi, bacteriophages, and helminths were diverse in gut of giant pandas, which provided basis for the further identification of role of gut microbiota. Besides, metagenomics revealed that the bacteria/fungi in gut of GPs harbor the ability of cellulose and hemicellulose degradation

    Genomic traits of multidrug resistant enterotoxigenic Escherichia coli isolates from diarrheic pigs

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    Diarrhea caused by enterotoxigenic Escherichia coli (ETEC) infections poses a significant challenge in global pig farming. To address this issue, the study was conducted to identify and characterize 19 ETEC isolates from fecal samples of diarrheic pigs sourced from large-scale farms in Sichuan Province, China. Whole-genome sequencing and bioinformatic analysis were utilized for identification and characterization. The isolates exhibited substantial resistance to cefotaxime, ceftriaxone, chloramphenicol, ciprofloxacin, gentamicin, ampicillin, tetracycline, florfenicol, and sulfadiazine, but were highly susceptible to amikacin, imipenem, and cefoxitin. Genetic diversity among the isolates was observed, with serotypes O22:H10, O163orOX21:H4, and O105:H8 being dominant. Further analysis revealed 53 resistance genes and 13 categories of 195 virulence factors. Of concern was the presence of tet(X4) in some isolates, indicating potential public health risks. The ETEC isolates demonstrated the ability to produce either heat-stable enterotoxin (ST) alone or both heat-labile enterotoxin (LT) and ST simultaneously, involving various virulence genes. Notably, STa were linked to human disease. Additionally, the presence of 4 hybrid ETEC/STEC isolates harboring Shiga-like toxin-related virulence factors, namely stx2a, stx2b, and stx2e-ONT-2771, was identified. IncF plasmids carrying multiple antimicrobial resistance genes were prevalent, and a hybrid ETEC/STEC plasmid was detected, highlighting the role of plasmids in hybrid pathotype emergence. These findings emphasized the multidrug resistance and pathogenicity of porcine-origin ETEC strains and the potential risk of epidemics through horizontal transmission of drug resistance, which is crucial for effective control strategies and interventions to mitigate the impact on animal and human health

    Evaluation of Bacterial Diversity and Quality Features of Traditional Sichuan Bacon from Different Geographical Region

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    Sichuan bacon is one of the most popular types of Chinese bacon in the domestic market. High-throughput sequencing was used to characterize the bacterial diversity of 39 Sichuan bacon samples collected from 3 geographical regions. The results showed that the bacterial diversity of Sichuan bacon in different regions demonstrated certain specificity as well as similarity, and the shared OTUs were close to 81% of the total number in the basin group, mountain group, and plateau group. At the genus level, Staphylococcus is the most dominant genus among the three groups, covering 26.7%, 20.6%, and 22.7%, respectively. Beta diversity shows significant differences in bacterial compositions in different geographic regions, especially for Pseudomonas, Brochothrix, Lactobacillus, Lactococcus, and Enterococcus. Meanwhile, some physicochemical characteristics were analyzed, and a significant difference (p &lt; 0.05) among the three regions was shown in the Aw, pH, and nitrite content, which were significantly correlated with undesired bacteria. This study provides insights into the understanding of the role of bacterial communities in the microbial safety and quality improvement of Sichuan bacon

    Facile Synthesis of N, S-Doped Carbon Quantum Dots from Food Waste as Fluorescent Probe for Sensitive Detection of Thiamphenicol and Its Analogues in Real Food Samples along with an Application in Bioimaging

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    Herein, N, S co-doped carbon quantum dots (N, S-CDs) with high absolute quantitative yield (Abs-QY) of 50.2% were produced by hydrothermal treatment of food residue crayfish shells. A new detection method of thiamphenicol (TAP) and its analogues was established by discovering the obvious fluorescence response between TAP and N, S-CDs, which achieved a wide linear range of 20–300 μg·L−1 with a detection limit (LOD) of 11.12 μg·L−1. This novel probe exhibited strong sensitivity and shows rapid response in complex food matrices (overall detection time is less than 45 min) mainly induced by static quenching. Spiked food sample recovery ranged from 97.3 to 99.34%. Further, the cell experiments of N, S-CDs were conducted, and the cell viability remained 91.76% under high concentration of N, S-CDs due to the environmentally friendly materials. The low cytotoxicity and good cytocompatibility make these N, S-CDs compatible for cell bioimaging and intracellular detection of TAP

    First Steps toward the Giant Panda Metabolome Database: Untargeted Metabolomics of Feces, Urine, Serum, and Saliva by 1H NMR

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    Differences in the concentration of metabolites in the biofluids of animals closely reflect their physiological diversities. In order to set the basis for a metabolomic atlas for giant panda (Ailuropoda melanoleuca), we characterized the metabolome of healthy giant panda feces (23), urine (16), serum (6), and saliva (4) samples by means of 1H NMR. A total of 107 metabolites and a core metabolome of 12 metabolites was quantified across the four biological matrices. Through univariate analysis followed by robust principal component analysis, we were able to describe how the molecular profile observed in giant panda urine and feces was affected by gender and age. Among the molecules modified by age in feces, fucose plays a peculiar role because it is related to the digestion of bamboo's hemicellulose, which is considered as the main source of energy for giant panda. A metagenomic investigation directed toward this molecule showed that its concentration was indeed positively related to the two-component system pathway and negatively related to the amino sugar and nucleotide sugar metabolism pathway. Such work is meant to provide a robust framework for further -omics research studies on giant panda to accelerate our understanding of the interaction of giant panda with its natural environment
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