Comparative analysis of camelid mitochondrial genomes

Camelus dromedarius has played a pivotal role in both culture and way of life in the Arabian peninsula, particularly in arid regions where other domestic animals cannot be easily domesticated. Although, the mitochondrial genomes have recently been sequenced for several camelid species, wider phylogenetic studies are yet to be performed. The features of conserved gene elements, rapid evolutionary rate, and rare recombination make the mitochondrial genome a useful molecular marker for phylogenetic studies of closely related species. Here we carried out a comparative analysis of previously sequenced mitochondrial genomes of camelids with an emphasis on C. dromedarius, revealing a number of noticeable findings. First, the arrangement of mitochondrial genes in C. dromedarius is similar to those of the other camelids. Second, multiple sequence alignment of intergenic regions shows up to 90% similarity across different kinds of camels, with dromedary camels to reach 99%. Third, we successfully identified the three domains (termination-associated sequence, conserved domain and conserved sequence block) of the control region structure. The phylogenetic tree analysis showed that C. dromedarius mitogenomes were significantly clustered in the same clade with Lama pacos mitogenome. These findings will enhance our understanding of the nucleotide composition and molecular evolution of the mitogenomes of the genus Camelus, and provide more data for comparative mitogenomics in the family Camelidae.

Cellular responses of hyaluronic acid-coated chitosan nanoparticles

In recent years, nanotechnology has been proven to offer promising biomedical applications for in vivo diagnostics and drug delivery, stressing the importance of thoroughly investigating the biocompatibility of potentially translatable nanoparticles (NPs). Herein, we report the cellular responses of uncoated chitosan NPs (CS NPs) and hyaluronic acid-coated chitosan NPs (HA-CS NPs) when introduced into Chinese hamster ovary cells (CHO-K1) in a dose-dependent manner (2.5, 0.25, 0.025, 0.0025, and 0.00025 mg mL-1) at two time points (24 and 48 h). MTS assay, cell proliferation, showed a decrease in the viability of cells when treated with 0.25 and 2.5 mg mL-1 CS NPs. When exposed to high doses of CS NPs, the lactate dehydrogenase (LDH) enzyme started to leak out of the cells and the cellular levels of mitochondrial potentials were significantly reduced accompanied by a high production of intracellular reactive oxygen species (ROS). Our study provides molecular evidence of the biocompatibility offered by HA-CS NPs, through ROS scavenging capabilities rescuing cells from the oxidative stress, showing no observed cellular stress and thereby revealing the promising effect of anionic hyaluronic acid to significantly reduce the cytotoxicity of CS NPs. Our findings are important to accelerate the translation and utilization of HA-CS NPs in drug delivery, demonstrating the pronounced effect of surface modifications on modulating the biological responses.

Molecular cloning, bioinformatics analysis, and expression of small heat shock protein beta-1 from Camelus dromedarius, Arabian camel

Small heat shock protein beta-1 (HSPB-1) plays an essential role in the protection of cells against environmental stress.Elucidation of its molecular, structural, and biological characteristics in a naturally wild-type model is essential. Although the sequence information of the HSPB-1 gene is available for many mammalian species, the HSPB-1 gene of Arabian camel (Arabian camel HSPB-1) has not yet been structurally characterized. We cloned and functionally characterized a full-length of Arabian camel HSPB-1 cDNA. It is 791 bp long, with a 5′-untranslated region (UTR) of 34 bp, a 3′-UTR of 151 bp with a poly(A) tail, and an open reading frame (ORF) of 606 bp encoding a protein of 201 amino acids (accession number: MF278354). The tissue-specific expression analysis of Arabian camel HSPB-1 mRNA was examined using quantitative real-time PCR (qRT-PCR); which suggested that Arabian camel HSPB-1 mRNA was constitutionally expressed in all examined tissues of Arabian camel, with the predominately level in the esophagus tissue. Peptide mass fingerprint-mass spectrometry (PMF-MS) analysis of the purified Arabian camel HSPB-1 protein confirmed the identity of this protein. Phylogenetic analysis showed that the HSPB-1 protein of Arabian camel is grouped together with those of Bactrian camel and Alpaca. Comparing the modelled 3D structure of Arabian camel HSPB-1 protein with the available protein 3D structure of HSPB-1 from human confirmed the presence of α-crystallin domain, and high similarities were noted between the two structures by using super secondary structure prediction.