In this paper, we focus on the camelid nanobodies as a revolutionary therapy that can guide efforts to discover new drugs for Coronavirus disease . The small size property makes nanobodies capable of penetrating efficiently into tissues and recognizing cryptic antigens. Strong antigen affinity and stability in the gastrointestinal tract allow them to be used via oral administration. In fact, the use of nanobodies as inhalant can be directly delivered to the target organ, conferring high pulmonary drug concentrations and low systemic drug concentrations and minimal systemic side effects. For that, nanobodies are referred as a class of next-generation antibodies. Nanobodies permit the construction of multivalent formats that may achieve ultra-high neutralization potency and then may prevent mutational escape and can neutralize a wide range of SARS-CoV-2 variants. Due to their distinctive characteristics, nanobodies can be of great use in the development of promising treatment or preventive strategies against SARS-CoV-2 infection. In this review, the state-of-the-art of camel nanobodies design strategies against the virus including SARS-CoV-2 are critically summarized. The application of general nanotechnology was also discussed to mitigate and control emerging SARS-CoV-2 infection.

No abstract

Camels (Camelus dromedarius) are known to harbor multidrug resistant Gram-negative bacteria and to be involved in the transmission of various microorganisms to humans. Data on the occurrence of colistin resistant Escherichia coli as well as mobilized colistin resistance (mcr) genes in camels are lacking. We investigated the presence of colistin resistance and mcr (1–2) genes in E. coli from the feces of camels in Tunisia. Presumptive E. coli isolates from camel-calves in southern Tunisia were qualitatively screened for growth on Mueller–Hinton agar supplemented with 2 mg/L of colistin. The minimal inhibitory concentration of colistin was determined for isolates growing on this medium. All isolates were screened for the presence of the mcr-1 and mcr-2 genes by polymerase chain reaction without detecting any of these genes. However, one isolate was confirmed resistant to colistin and further testing of this isolate revealed it to be Enterobacter cloacae. Our study demonstrated absence of colistin resistance and of the mcr-1 and mcr-2 genes in E. coli isolated from camel feces in southern Tunisia. Thus, there is no evidence that camels represent a major source of mcr genes contamination for the local population or for tourists visiting southern Tunisia.

In many mammalian species, newborns are agammaglobulinemic; thus, colostrum and milk are the main sources of early protective antibodies. These antibodies are produced in the mother's serum and transferred to mammalian glands a few days before parturition. Here, we have studied the transfer of immunity from a she-camel immunized with human serum albumin (HSA) to her calf via colostrum and milk. Our results show that HSA-specific antibodies are produced in the mother's serum and are subsequently transferred to her colostrum. These specific antibodies are then transferred by suckling to the calf. The calf serum did not contain HSA-reactive antibodies at parturition and before the first feed, after suckling, a rise in reactivity was observed peaking at 24 h postpartum. The involvement of heavy chain antibodies (HCAbs) in the process of immunity transfer was also examined, and it was found that they were also transferred from the colostrum to the calf serum like conventional antibodies.

This study aims to determine the relationship between internal and external udder and teat measurements and evaluate their correlation with milk yield and milk partitioning in the udder of dromedary camels. Six Maghrebi camels reared under intensive conditions were monitored at early, middle, and late lactation. Udder measurements included udder depth, udder horizontal circumference, fore and rear teat length and diameter. Besides, scans of the left fore and rear quarters were taken in duplicate before morning milking (16 h) using an oxytocin receptor blocking agent (Atosiban) to determine teat and gland distension before milk ejection. Cisternal and alveolar milk volumes were then evaluated. Correlation coefficients were calculated between the performed udder external and ultrasonographical measurements and cisternal and daily milk production on the measurement day. Significant effect of lactation stage was observed in all measured traits. All internal and external measurements decreased significantly at late lactation as well as cisternal and total milk yield. The quarter cisternal area averaged 16.3 ± 2.2 cm(2) and decreased about three times at late lactation compared to early and middle lactation. All external and internal measurements were positively and highly correlated (P < 0.001). The knowledge of the relationship between udder internal and external morphological traits would permit to predict udder cisternal storage capacity and can ultimately be adopted to improve milk storage capacity of dromedary camels.

No abstract

Gelatin is a natural polymer that can be derived from collagen through hydrolysis. It most extensively used in diverse fields, mainly in pharmaceuticals and therapeutic. Herein Gelatin was newly extracted from camel (Camelus dromedarius) skin and irradiated with gamma rays from 60 Co source. Gelatin was optimized and characterization and functional properties were determined. The structural changes occurring after γ-irradiation at doses from 5 to 30 kGy were reported by physico-chemical techniques such as electron paramagnetic resonance (EPR), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) for the first time. Results revealed that gelatin yield increased significantly (P<0.05) as the extraction temperature and time increased (19.71%) at 70°C for 12 h. EPR spectroscopy demonstrated that 10 kGy of radiation-induced the decomposition of side groups. New peak positions (Paramagnetic centers) were located at around 3800 G. Moreover, an enhancement of EPR peak (3300 and 3400 G) (g-factor = 2.0) was detected. In addition, free radicals trapped in the crystalline regions were moved toward the boundary regions and the amorphous phases disappeared. XRD patterns showed a new peak at 2θ= 65.8° and a diminution of the relative intensity for the peak of 2θ= 20.54° after 30 kGy. FTIR measurements revealed structural deformations from 5 kGy through chain scission of C-H chains as well as the deformation of the C=O carboxyl groups with increasing γ-radiation doses. The camel skin was thus proved to be a source of gelatin. Irradiation induced a structural deformation with desirable functionalities that make it a potent source of gelatin that could be used in food and biomedical applications.

No abstract