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In this study, non-targeted metabolomics based on ultra-high performance liquid chromatography Q-Exactive-mass spectrometry (UPLC-Q-Exactive-MS) was used to explore the differences in the metabolite profiles of muscles from Bactrian camels slaughtered at different ages. The results showed that a total of 710 differentially expressed metabolites (DEMs) were identified in the longissimus dorsi muscle of camels from three age groups: I (3–4 years old), II (6–7 years old), and III (9–10 years old). In total, 78 DEMs were found in groups I vs II, of which 47 were upregulated in group I and 31 were upregulated in group II. Totally, 49 DEMs were identified in groups II vs III, of which 18 were upregulated in group II and 31 were upregulated in group III. In addition, 65 DEMs were identified in groups I vs III, of which 29 were upregulated in group I and 36 were upregulated in group III. The results of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the DEMs were mainly enriched in pathways such as protein and amino acid metabolism, fatty acid metabolism, and vitamin and mineral metabolism, indicating that the digestion and metabolism of various nutrients in camels were different at different growth stages. The contents of polyunsaturated fatty acids (PUFA) (especially n-6 PUFA and n-3 PUFA) and the PUFA/unsaturated fatty acid (UFA) ratio were significantly higher in group I than III, which was mainly related to the significant upregulation of arachidonic acid, linoleic acid and 13-L-hydroperooleic acid concentrations in relevant metabolic pathways. Meanwhile, DEMs such as L-leucine, L-valine, and L-glutamine could serve as potential markers for evaluating the quality change of camel meat at different slaughter ages.

The differences in the proteomes of camel meat from different age groups were analyzed by tandem mass tag (TMT)-based quantitative proteomics and liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify the key quality-related proteins of camel meat. The results showed that differentially expressed proteins (DEPs) had an important effect on the quality of camel meat. A total of 311 DEPs were identified in the longissimus dorsi muscle of camels from three age groups, 3–4 (I), 6–7 (II), and 9–10 (III) years old. Altogether 245 DEPs were identified in groups I versus II, 16 in groups II versus III, and 139 in groups I versus III. In addition, 194, 1, and 110 DEPs were up-regulated, and 51, 15, and 29 DEPs were down-regulated in the three comparison groups, respectively. Gene Ontology (GO) functional annotation analysis indicated that structural proteins, metabolic proteins, and heat stress proteins could be used as biomarkers for discrimination among camel meat from different ages. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the DEPs were mainly involved in fatty acid metabolism, glycolysis/glucose production, amino acid biosynthesis, and the hypoxia inducible factor-1 (HIF-1) signaling pathway. Protein-protein interaction (PPI) analysis showed that metabolic enzyme proteins were key network-connecting proteins that affect camel meat from different ages. Correlation analysis showed that 16 DEPs were correlated closely with meat tenderness. The tenderness of camel meat from the three age groups was mainly influenced by actin, histone and protein kinases. The results of this study can provide a scientific basis for the grading and evaluation of camel meat, the selection of optimal slaughter age, and the study of camel meat quality characteristics.

Abstract Background The family Camelidae that evolved in North America during the Eocene survived with two distinct tribes, Camelini and Lamini. To investigate the evolutionary relationship between them and to further understand the evolutionary history of this family, we determined the complete mitochondrial genome sequence of the wild two-humped camel (Camelus bactrianus ferus), the only wild survivor of the Old World camel. Results The mitochondrial genome sequence (16,680 bp) from C. bactrianus ferus contains 13 protein-coding, two rRNA, and 22 tRNA genes as well as a typical control region; this basic structure is shared by all metazoan mitochondrial genomes. Its protein-coding region exhibits codon usage common to all mammals and possesses the three cryptic stop codons shared by all vertebrates. C. bactrianus ferus together with the rest of mammalian species do not share a triplet nucleotide insertion (GCC) that encodes a proline residue found only in the nd1 gene of the New World camelid Lama pacos. This lineage-specific insertion in the L. pacos mtDNA occurred after the split between the Old and New World camelids suggests that it may have functional implication since a proline insertion in a protein backbone usually alters protein conformation significantly, and nd1 gene has not been seen as polymorphic as the rest of ND family genes among camelids. Our phylogenetic study based on complete mitochondrial genomes excluding the control region suggested that the divergence of the two tribes may occur in the early Miocene; it is much earlier than what was deduced from the fossil record (11 million years). An evolutionary history reconstructed for the family Camelidae based on cytb sequences suggested that the split of bactrian camel and dromedary may have occurred in North America before the tribe Camelini migrated from North America to Asia. Conclusion Molecular clock analysis of complete mitochondrial genomes from C. bactrianus ferus and L. pacos suggested that the two tribes diverged from their common ancestor about 25 million years ago, much earlier than what was predicted based on fossil records.

Food safety has become an important public health issue, rapid and accurate monitoring and detection of foodborne pathogens is one of the most effective ways to control and prevent human foodborne diseases. The complexity of food matrices, the diversity of bacteria and their different growth and replication characteristics pose a major challenge for the detection of foodborne pathogens. Traditional microbial detection methods are time-consuming and laborious, and cannot meet the requirements of non-culturable viable bacterial cells and rapid on-site food detection. Therefore, in recent years, various immunoassays for foodborne pathogens have been developed, which are more sensitive, simple and efficient than the traditional methods, and have broad application prospects. Based on the biological characteristics of sublethal injury, viable but non-culturable (VBNC) and dormant states, as well as the types and characteristics of antibodies, this paper reviewed the detection principle, advantages and disadvantages, and applications of the current common immunoassays for foodborne pathogens. The limitations of the existing methods and the future development direction were discussed to provide reference for the development and utilization of immunoassays for foodborne pathogens. [ABSTRACT FROM AUTHOR]

In this study, camel placenta was used as raw material to screen the optimal preparation conditions of protease and its antioxidant peptides, and then the antioxidant peptides of camel placenta with different molecular weights were separated by ultrafiltration to evaluate their in vitro antioxidant activity and stability. Results showed that the best conditions for the preparation of camel placenta antioxidant peptides were determined by single-factor and response surface optimization tests using papain enzymatic digestion of camel placenta and the degree of hydrolysis as the evaluation index. When the enzymatic digestion time was 3 h, the enzymatic digestion temperature was 57.5°C, the enzyme addition was 4 770 U/ g, and the pH of enzymatic digestion was 6.3, the degree of hydrolysis reached 42.21% under these conditions. The activity of camel placenta antioxidant peptides remained stable in high temperature, weakly acidic and neutral environments, while the antioxidant capacity decreased under alkaline conditions. After gastrointestinal protease digestion, DPPH radical scavenging rate was the first to rise by 4.63% and then declined, and ABTS cationic radical scavenging rate was significantly higher by 2.21% (P < 0.05). This study may provide a theoretical basis for the production processing and application of camel placenta antioxidant peptides in camel placenta. [ABSTRACT FROM AUTHOR]

Nanobody has become an important tool for immunoassays because of its stability, specificity, and ease of expression. To monitor the aflatoxin M1 in dairy products, the anti-AFM1 nanobody, named M6, selected from the Bactrian camel AFM1 immune library, evaluated its properties, and developed an indirect competitive enzyme-linked immunosorbent assay (icELISA). After optimizing the parameters, including the blocking method, methanol concentrations, pH values, and ionic strength in the reaction system, a standard competitive inhibition curve was established, and methodological specificity and accuracy was verified. Results showed that Nb-M6 had a good affinity and thermal stability, the limit of detection (LOD) of Nb-icELISA was 0.111 ng/ mL, and the half maximal inhibitory concentration (IC50) was 1.498 ng/ mL. The recoveries of dairy products spiked were 89.8% - 104.1%, which were in agreement with the high-performance liquid chromatography (HPLC). The Nb-icELISA is simple, convenient and can be applied to batch screening of AFM1 in dairy products. [ABSTRACT FROM AUTHOR]

objective: To investigate the alleviating mechanism of camel milk on non-alcoholic fatty liver disease (NAFLD) in mice. Methods: Thirty C57BL/6J mice were randomly assigned into three groups: negative control group (NC group), model group (Mod group) and camel milk group (CaM group). The negative control group was fed control diets, the model and camel milk groups were fed high-fat diets, and camel milk was given daily by gavage to the camel milk group mice. The experiment lasted for 12 weeks, and the NAFLD model was established. The alleviation mechanism of NAFLD in mice by camel milk was investigated by analyzing biochemical indices, liver pathological structure and liver lipidome. Results: With the intervention of camel milk, the body weight, blood glucose and liver index of NAFLD mice were significantly reduced to 31.45 g, 8.85 mmol/mL and 3.98%, respectively (L<0.05); the levels of total triglyceride (TG), total cholesterol (TC) and low density lipoprotein (LDL-c) in serum were significantly reduced to 0.657 mmol/mL, 4.689 mmol/mL, and 9.923 mol/mL, respectively (L<0.05); the levels of TG and TC in liver were dramatically reduced to 0.034 mmol/mL and 0.009 mmol/mL, respectively (L<0.05); liver tissue structure was intact and clear, and the lipid accumulation was reduced in the liver. Lipidomic analysis showed that the relative levels of choline (CEs), diglycerides(DGs), unsaturated triglycerides (TGs), phosphatidylcholine (PC) and lysophosphatidylcholine (LPCs) were increased in the liver of mice in the CaM group; lipid metabolites were enriched in sphingolipid metabolism, glyc-erol ester metabolism and glycerophospholipid metabolism. Conclusion: Camel milk alleviates NAFLD by modulating sph-ingolipid metabolism, triglyceride metabolism and glycerophospholipid metabolism in mice with NAFLD by altering liver lipid profiles. [ABSTRACT FROM AUTHOR]