Search Results (63)

Background/Objectives: Single-domain antibodies (sdAbs) are derived from camelid heavy-chain antibodies (HCAb). Their small size, high stability, and ease of production, among other properties, makes them highly valuable in biomedical research and therapeutic development. Several sdAb-based molecules are currently progressing through clinical trials, highlighting their translational relevance. As sdAbs originate from HCAb of Camelidae family, they can originate from multiple species including Vicugna pacos, Lama glama, Camelus dromedarius and Camelus bactrianus. Although several reports and databases analyze the structure of sdAbs, comprehensive evaluations on species-dependent structural differences remain scarce. Methods: We assembled MO-IISA, an open-access curated database of sdAbs with known antigen targets by integrating six public resources (iCAN, INDI, SAbDab-nano, sdAb-DB, PLabDab-nano, NbThermo) under harmonized eligibility criteria. Results: The final dataset comprises 2053 sdAbs derived from llamas (Lama glama, n = 1316); alpacas (Vicugna pacos, n = 325), dromedary camels (Camelus dromedarius, n = 377) and Bactrian camels (Camelus bactrianus, n = 35). We quantified region lengths, amino acid frequency, and conservation/entropy across frameworks (FR1–FR4). The average length of all sdAbs was about 124 ± 8 amino acids, with minor interspecies differences. We observed a consistent enrichment of lysines in FR3 (and secondarily FR2) and cysteines primarily in FR1 and FR3, with non-canonical cysteines more frequent in Bactrian and dromedary sdAbs CDRs. CDR2 and, particularly CDR3, contributed most to inter- and intra-species variability, whereas FRs were highly conserved. Conclusions: Species-neutral framework constraints and species-tuned loop adaptations have practical implications for sdAb engineering, species selection, and conjugation strategies. These features are captured in MO-IISA, an open-access database of known-target sdAbs from different species. Full article

The Bactrian camel is a key economic livestock species in China and around the world. It yields meat and milk (high-quality functional foods), and the milk reports health benefits. Dromedary camels, as intermediate hosts of MERS-CoV, have garnered significant public health attention. In contrast, viral surveillance in Bactrian camels from the same genus as dromedaries has received limited attention, with only sporadic or regionally confined reports available. Systematic investigations into the virome of viral species, viral diversity, and novel viruses in Bactrian camels are lacking. In this study, swabs were collected from 701 Bactrian camels in China. Through metagenomics, 3262 viral contigs were classified into 16 viral phyla, 29 viral families, and an unclassified group. The different landforms were found to influence viral diversity and composition in Bactrian camels, with mountainous area exerting the greatest impact. The viral composition significantly differed between captive and free-ranging camels. The study identified at least 12 viruses with zoonotic potential, and phylogenetic analysis indicated cross-species transmission in some of them. Additionally, picornavirus, circular Rep-encoding single-stranded (CRESS) DNA virus, and polyomavirus from Bactrian camels may represent novel species or genotypes. To summarize, in this study, we described the baseline virome profile of Chinese Bactrian camels, investigated the ecological factors influencing the viral distribution of Bactrian camels, identified key potential viral risks, and provided a scientific basis for the prevention, control, and early warning of critical viral diseases in Bactrian camels from China. Full article

The Bactrian camel exemplifies mammalian adaptation to deserts, but the spatial organization of its innate immune system remains uncharacterized. This study integrated transcriptomes from 110 samples across 11 major tissues and organs to resolve tissue-specific gene expression and innate immune modularity. Through differential expression analysis, Tau specificity index (τ > 0.8), and machine learning validation (Random Forest F1-score = 0.86 ± 0.11), we identified 4242 high-confidence tissue-specific genes (e.g., LIPE/PLIN1 in adipose). Weighted gene co-expression network analysis (WGCNA) of 1522 innate immune genes revealed 11 co-expression modules, with six exhibiting significant tissue associations (FDR < 0.01): liver-specific (r = 0.96), spleen-adipose-enriched (r = 0.88), muscle-associated (r = 0.82), and blood-specific (r = 0.80) modules. These networks demonstrated multifunctional coordination of immune pathways—including Pattern Recognition, Cytokine Signaling, and Phagocytosis—rather than isolated functions. Our results establish that camel innate immunity is organized into spatially modular networks tailored to tissue microenvironments, providing the first systems-level framework for understanding immune resilience in desert-adapted mammals and may inform strategies for enhancing livestock resilience in arid regions. Full article

Body measurements are used regularly to describe phenotypes or the weight of animals. However, little data describe the age effect on the different measurements. In the present paper, 477 Bactrian camels (7–180 months old) were measured (length of the head, length and circumference of the neck, height at the withers, girth circumference, length of the front leg, and length of the body), and their growth was modeled by comparing different equations, the most convenient being the beta growth equation. In addition, the differences in body measurements of adult Bactrian camels between farms were tested by variance analysis, and multivariate analyses were used for identifying homogeneous clusters of camels according to their body measurements. The sampled animals were from different regions of the country. The significant relationships between cluster and region support the idea of racial differentiation. Body condition scoring is widely used in farm animals as an indicator of their feeding, health, and welfare status. If a body condition score is available for dromedaries, there is no specific grid for the Bactrian camel. Starting from typical examples taken from photos in different conditions, including extreme ones, a representation of a scoring system of 6 points from very emaciated (score 0) to overweight Bactrian camel (score 5) was proposed in the form of drawings from the right side, back, and three-quarter rear. To complete the drawings, a descriptive grid was built as a base for training stakeholders in relation to Bactrian camel farm management. However, the seasonal change in the fleece abundance, the variability of the humps’ shape, and the presence of crossbreeding with dromedary camels require adapting the scoring accordingly. Full article

Camel poll gland tissues (PGs) secrete amber liquid and volatile substances during the breeding season, inducing estrus and mating in female camels. These processes are mainly regulated by steroid hormones and their receptors, including the Androgen Receptor (AR). However, the functional components of PGs and their regulatory mechanisms in camel reproduction remain unclear. Therefore, in this study, we identified candidate differentially expressed metabolites (DEMs) and differentially expressed proteins (DEPs) associated with steroids through a multi-omics analysis of PGs during the male camel breeding season. We found that total cholesterol and testosterone concentrations were significantly increased in camel PGs at different stages of the breeding season. DEMs and DEPs related to cholesterol or steroids were analyzed using metabolomics and data-independent acquisition proteomics in the PGs of male Bactrian camels at different stages (early and peak breeding seasons), and the potential mechanism of steroid hormone synthesis was further explored. The metabolomics results identified 13 DEMs related to steroids in PGs at different stages. The proteomics results revealed seven GO terms and 69 DEPs related to steroids, with apolipoprotein E (APOE) identified as the core DEP. Pathway analysis confirmed that APOE and related DEPs were involved in cholesterol and steroid hormone synthesis. Immunostaining showed that APOE and AR were co-localized in the cytoplasm of acinar epithelial cells, and exhibited opposite expression trends in PGs during different breeding stages. These findings demonstrate that APOE- and AR-mediated cholesterol metabolism plays an important role in steroid hormone synthesis during camel reproductive activity, providing valuable insights into the mechanisms of steroid synthesis in PGs. This study offers a theoretical framework for understanding camel reproductive biology, particularly the interplay between APOE and AR in regulating cholesterol metabolism and steroidogenesis. Full article

Camels have developed unique adaptive mechanisms, one of which is the active accumulation of lipids. This metabolic feature has a direct influence on the liver ultrastructure. Its analysis reveals how exactly the hepatocytes have evolved to effectively store fat and neutralize toxins, which is crucial for survival in the desert. Considering the latter, the aim of this research is to establish the features of the microstructural organization of the liver of the Bactrian camel (Camelus bactrianus). This study was conducted using 15 liver tissue fragments from 5 healthy Bacterian camels (3 pieces from each animal) via biopsy. The sections were examined using a JEM-1011 electron microscope at magnifications of 2500–8000. Electron microscopic analysis of hepatocytes revealed a significantly larger hepatocyte diameter (25–30 µm), suggesting an adaptation for metabolites and water storage. Hepatocytes exhibited fewer, medium-sized (0.5–2 µm) lipid droplets, present in only 12–15% of cells. A high density of specialized Kupffer (15–20 cells per 10,000 µm²) and activated Ito cells was observed, indicating enhanced detoxification and immune functions. These specific ultrastructural features provide a model for studying metabolic resistance and inform veterinary diagnostics and husbandry practices for this species. Full article

Plantsterol esters (PSEs) exert beneficial effects on animal product quality, indicating their potential as a nutritional intervention strategy. This study investigated the effects of dietary PSE supplementation on lactation performance and lipid metabolism in Tarim Bactrian camels (Camelus bactrianus) to establish a scientific basis for its application in their husbandry. Thirty-two mid-lactation female camels were randomly allocated to four groups (n = 8): CON (basal diet), L (200 mg/kg PSE), M (400 mg/kg PSE), and H (800 mg/kg PSE). Since lactation performance is closely linked to metabolic status, biochemical and lipidomic analyses were conducted on serum and milk samples. Analysis revealed that the H group showed significantly increased milk yield, lactose yield, and milk fat yield compared to other groups. Serum cholesterol levels decreased progressively with higher PSE supplementation, while serum urea levels rose dose-dependently. Blood Glu was lower in the L group but higher in the H group relative to CON. Lipidomic profiling identified 644 and 257 differential metabolites in milk and serum, respectively. Milk metabolites were enriched in the EGFR inhibitor resistance, MAPK, and ErbB signaling pathways; serum metabolites were linked to glycerophospholipid, arachidonic acid, and linoleic acid metabolism. These findings indicate that PSE-modulated metabolites in serum and milk significantly influence lactation performance and glucolipid metabolism in Tarim Bactrian camels, supporting further investigation into precision nutrition strategies. Full article

Testicular development in male animals is a conserved and highly regulated biological process. Investigating the molecular mechanisms underlying testicular development in Junggar Bactrian camels is essential for gaining a deeper understanding of this process in the species. This study selected testicular tissue from the Junggar Bactrian camel at pre-sexual maturity (G3 group, n = 4, 3 years old) and post-sexual maturity (G5 group, n = 4, 5 years old) for whole transcriptome sequencing and bioinformatics analysis. We identified differentially expressed mRNA (DEmRNA), including KPNA2 and LRRC46; differentially expressed LncRNA (DELncRNA), including LOC123613926 and LOC123613624; and differentially expressed miRNA (DEmiRNA), including eca-miR-196a and eca-miR-183. Additionally, we also identified 87 currently unnamed DEmiRNAs, which are of practical value for future research on the Junggar Bactrian camel testicular development and spermatogenesis. GO and KEGG enrichment analyses showed that DERNA are mainly involved in functions and processes such as protein binding (MF), protein import into nucleus (BP), and extracellular space (CC), as well as signaling pathways such as Insulin, FoxO, MAPK, and PI3K-Akt. Subsequently, we predicted some DEmiRNAs and DELncRNAs association with DEmRNAs, and constructed the competitive endogenous RNA (ceRNA) regulatory network. Finally, we randomly selected 10 DERNAs for RT-qPCR validation, and the transcriptome results were consistent with the RT-qPCR results, indicating that the sequencing results were true and reliable. In conclusion, this study analyzed the differential expression of mRNA, LncRNA, and miRNA in Junggar Bactrian camels before and after sexual maturity, providing data references for future studies related to testicular development and spermatogenesis. Full article

The poll gland, a specialized tissue of male Bactrian camels, undergoes seasonal enlargement and marked metabolic activation during the rutting season. However, the metabolic mechanisms of the poll gland and its role in rutting activities and inducing estrus are still not fully understood. This study aimed to investigate the contribution of fatty acid metabolic pathways, specifically those mediated by carnitine palmitoyltransferase 1A (CPT1A), in poll gland activity during the breeding season; poll gland tissue, neck mane, and urine samples were systematically collected from healthy male Bactrian camels stratified into breeding and non-breeding season groups for integrated proteomic, metabolomic, and biochemical assays. Histological and immunohistochemical analyses revealed reduced adipocytes but elevated ATP production in rutting camels, suggesting increased mitochondrial activity and enhanced oxidative phosphorylation. Proteomic analyses identified 119 differentially expressed proteins (DEPs) linked to fatty acid metabolism, with CPT1A, a key regulator of mitochondrial fatty acid oxidation, emerging as a central hub. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis further confirmed enrichment in fatty acid biosynthesis, degradation, and PPAR/AMPK signaling. The metabolomic analysis identified 14 metabolites, including acetylcarnitine and glycine, that were closely correlated with CPT1A expression, suggesting their potential involvement in regulating fatty acid metabolism during the breeding season. Quantitative expression analyses revealed that CPT1A in glandular acini was significantly upregulated in the breeding group compared to the non-breeding group across all assays: qPCR (2.53-fold, p < 0.05), Western blot (3.5-fold, p < 0.05), and immunohistochemistry (1.5-fold, p < 0.05). This demonstrated that CPT1A-mediated fatty acid metabolism plays a pivotal role in energy provision for reproductive activities. The results suggested that CPT1A-mediated fatty acid oxidation sustains poll gland function and reproductive behaviors in male Bactrian camels. This study provided a theoretical basis for understanding the role of CPT1A-mediated fatty acid oxidation in maintaining poll gland function and supporting reproductive activities in male Bactrian camels. Full article

Camels have been essential to human survival and development across the arid Central Asian steppes, particularly in Kazakhstan, where the breeding of one-humped and two-humped camels is a longstanding tradition supporting the nomadic lifestyle. This study aimed to assess the genetic diversity and population structure of these camels across their distribution range in Kazakhstan. Blood samples from 100 individuals were collected from five locations, Almaty (ALA), Atyrau (ATR), Shymkent (SHK), Kyzylorda (KZL), and Taraz (TRZ), and genotyped using 17 microsatellite markers. All loci were polymorphic, with a mean observed heterozygosity of 0.707 in C. dromedarius and 0.643 in C. bactrianus. The highest expected heterozygosity (He = 0.939) was observed at VOLP67 in C. bactrianus and at VOLP03 in C. dromedarius. Genetic differentiation was low (FST = 0.021), indicating a weak population structure between the two species with substantial gene flow (Nm = 19.972). The hybrid analysis identified 31% hybrids, including F1, F2, and backcrosses, with the highest frequencies in KZL and TRZ, moderate frequencies in ATR, and lowest frequencies in SHK and ALA. These patterns, consistent with STRUCTURE clustering, reflect widespread but regionally variable hybridization. The phylogenetic analysis revealed three clades, separating Bactrian camels (ALA), dromedaries (SHK), and a hybrid group (ATR, KZL, and TRZ). These findings enhance our understanding of the genetic diversity of Kazakhstan’s camels and support effective conservation, breeding strategies, and genotyping applications in camel husbandry. Full article

The Junggar Bactrian camel, a primitive indigenous breed in China, exhibits low reproductive efficiency under natural grazing conditions. This is partly attributed to the development of the epididymis and the quality of semen, both of which directly affect reproductive performance. The epididymis is a key male reproductive organ responsible for sperm storage and transport. However, the gene expression profile of camel epididymal tissue remains poorly understood. In this study, we conducted whole-transcriptome sequencing of epididymal tissues from Junggar Bactrian camels before and after sexual maturity. A total of 683 differentially expressed mRNAs (DEmRNAs) were identified, including TPM2, ITGA5, FASN, and ACP5, of which 415 were upregulated and 268 were downregulated. Additionally, 260 differentially expressed long non-coding RNAs (DELncRNAs), including LOC123611838, LOC105083505, and LOC123614702, were identified, with 113 upregulated and 147 downregulated. An additional 11 differentially expressed microRNAs (DEmiRNAs), including eca-miR-206 and eca-miR-216a, were also detected. Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed that key differentially expressed genes (DEGs), including TPM2, ITGA5, DDIT4, FASN, and ACP5, were mainly involved in pathways such as Cell Adhesion Molecules, Phospholipase D signaling, Cytokine–Cytokine Receptor Interaction, and Olfactory Transduction. This study presents a comprehensive whole-transcriptome analysis of the epididymis in Junggar Bactrian camels before and after sexual maturity, identifying key genes and regulatory pathways associated with epididymal development and reproductive function. These findings provide a theoretical foundation and valuable data for future research on reproductive performance and epididymal biology in Bactrian camels. Full article

Subclinical mastitis is a critical disease affecting camel health and milk quality. However, research on shifts in milk bacterial communities following subclinical mastitis in camels is limited. We evaluated changes in bacterial communities following subclinical mastitis in Bactrian camels. Three portions of California Mastitis Test (CMT)-negative milk and five portions of CMT-positive milk were collected from each Jimunai County and Keping County using the CMT, and the bacterial community composition of the camel milk was analyzed using amplicon sequencing of the v34 region of the 16S rRNA gene. Subclinical mastitis induced genus-level differences in the core bacterial microbiota of Bactrian camel milk. To our knowledge, Delftia was identified in camel milk for the first time, predominantly in Jimunai County. Bacterial abundance in camel milk from Keping County was increased and altered. Alpha diversity analysis revealed that subclinical mastitis induced lower and higher bacterial abundance in milk from Jimunai County and Keping County, respectively, compared to that of healthy camels. Therefore, these findings provide direction for future research on pathogenic microorganisms for the prevention and control of subclinical mastitis in Bactrian camels. Full article

Immune checkpoint inhibitors like programmed cell death 1 (PD-1) antibodies have revolutionized cancer treatment, but patient response rates remain limited. Sialic acid-binding Ig-like lectin 15 (Siglec-15) has emerged as a promising new immune checkpoint target. Through phage display technology using a Bactrian camel immunized with recombinant human Siglec-15, we generated six anti-Siglec-15 camelid nanobodies and constructed chimeric heavy-chain antibodies by fusing the VHH domains with human IgG-Fc. Following expression in HEK293-F cells and purification, three antibodies (S1, S5, S6) demonstrated specific binding to both human and murine Siglec-15 in ELISA and biolayer interferometry assays. In a xenograft model established by subcutaneous inoculation of NCI-H157-S15 cells into BALB/c nude mice, these antibodies showed distinct tumor targeting and significant blockade of Siglec-15 interactions with CD44, MAG, sialyl-Tn, and LRR4C ligands. All three antibodies exhibited anti-tumor effects, with S1 showing the most potent activity. S1-treated mice had significantly smaller tumor volumes and weights compared to controls. The S1, S5, and S6 treatment groups showed enhanced anti-tumor immunity, with reduced TGF-β, IL-6, and IL-10 levels. Notably, S1 treatment significantly increased tumor-associated macrophages in tumor tissues (p < 0.05). In conclusion, S1 exhibits remarkable anti-tumor activity and has the potential to be developed as a cancer immunotherapy targeting Siglec-15. Full article

Camels survive in deserts through unique, adapted metabolic and immunological processes that are normally lethal to other species. Antioxidants and the gastrointestinal microbiota play major roles in redox homeostasis, yet they remain unexplored in camels to date. The objectives of this study were to characterize the dynamics of milk antioxidants, serum antioxidants, and the fecal microbiome of lactating Bactrian camels with different parities. In total, 30 lactating camels were selected and categorized into the following 3 groups: 10 were assigned to the first parity group (P_1), 10 were classified into the third parity group (P_3), and 10 belonged to the fifth parity group (P_5). The antioxidant parameters of the lactating camels were determined in milk and serum. The fecal microbial community of lactating camels was assessed using 16S rRNA amplicon sequencing, and the resulting library was sequenced on an Illumina NovaSeq platform. The amount of total antioxidant capacity (T-AOC) and antioxidant activity for polypepetides (DPPH) in the third parity was the highest among the groups both in the camel milk and its serum. In the case of hydroxyl radical (OH) and SOD, the amounts were 9.62 U/mL (SEM = 0.4950) and 13.64 U/mL (SEM = 0.5144), respectively, for P_1 in the serum, which were extremely significantly greater than those of the other groups. The Shannon index was significantly different between the P_1 group and either the P_3 or P_5 group. Additionally, Simpson’s diversity index significantly differed between the P_1 group and the P_5 group. Furthermore, the number of OH in camels is positively associated with the metabolic pathway of non-oxidative pentose phosphate pathway and ANAGLYCOLYSIS-PWY. In conclusion, this study revealed that different parities were associated with distinct levels of antioxidant parameters and fecal microbial ecologies in lactating Bactrian camels, where parity affects metabolic and microbial health. Understanding these dynamics in camels could optimize their nutritional management, enhancing their welfare in challenging environments. Full article

Camel breeding in Europe has undergone significant changes, intertwining historical continuity with modern innovation. Historically, dromedaries (Camelus dromedarius) and Bactrian camels (Camelus bactrianus), played essential roles in Roman logistics, medieval rituals, and agriculture, leaving archeological and cultural footprints across Europe. Following a decline during the Middle Ages, camels were largely confined to exotic collections. However, the past few decades have witnessed a resurgence in camel farming, primarily driven by tourism and the demand for camel milk, with an estimated 5000–6000 camels now present in Europe. Despite their adaptability to harsh climates and nutritional advantages, the sector faces challenges such as small population sizes, fragmented breeding efforts, and the absence of regulatory frameworks tailored to camels. Advances in genomic tools, including genome-wide association studies and SNP genotyping, have created opportunities for the genetic management of camels in Europe, yet also reveal concerns about low genetic diversity stemming from founder effects. Addressing these issues requires coordinated international efforts, standardized phenotype recording, and enhanced welfare guidelines. With climate change highlighting the resilience of camels to arid environments, their potential as sustainable livestock remains promising. This review underscores the balance between preserving the historical legacy of camels in Europe and fostering their integration into contemporary agricultural systems. Full article