Immunolocalization of arginine kinase (AK) in Toxocara canis, Toxocara vitulorum, and Ascaris lumbricoides

Abstract

Arginine kinase (AK) is a member of the phosphagen kinase family. AK plays a major role in cellular energy metabolism in invertebrates including nematodes. In the present study, we performed the direct immunofluorescence test to determine the immunolocalization of AK in different stages of the life cycle (eggs, larvae, and adult worms) of Toxocara canis, Toxocara vitulorum, and Ascaris lumbricoides. Our results indicated variable levels of expression of AK in different stages. Moreover, strong fluorescence was observed in cleaving eggs than in dormant eggs. The highest activity of the enzyme was observed in the fully developed eggs. This may be due to high expression of AK in embryonic development, which is associated with increased energy demand due to cleavage and cellular differentiation. Surprisingly, expression of AK is significantly higher in the middle part and posterior end compared to anterior end of the larvae. In addition, AK is highly concentrated in cellular and metabolically active parts of the body such as hypodermis, muscle, intestine, ovaries, oviducts, and uterus, while it is absent in noncellular areas like cuticle. The present study revealed the presence of AK in T. canis, A. lumbricoides, and T. vitulorum and that it plays a major role in energy metabolism of these nematodes. Interestingly, antiserum was prepared against the recombinant T. canis AK and reacts with the native AKs of T. canis, A. lumbricoides, and T. vitulorum. AK levels could vary in relation to maximum potential rates of ATP turnover, oxidative capacity, and energy output. Further studies on subcellular localization of AK in these important helminths provide new information for researchers to develop effective anthelmintics against the parasites of veterinary and of public health importance.

Selection of Reliable Reference Genes for RT-qPCR Analysis of Bursaphelenchus mucronatus Gene Expression From Different Habitats and Developmental Stages

“…AK is a phaosphagen kinase which plays a critical role in energy mobilization in invertebrates ( Matthews et al, 2003 ). The AK gene family comprises two members in nematodes ( AK1 and AK2 ), which are differentially expressed at different developmental stages ( Kulathunga et al, 2012 ; Qi et al, 2015 ). Our results demonstrated the reliability of the TUB / HIS / 18S rRNA combination as reference genes to normalize the transcription of AK1 and AK2 , as the expression levels of the target genes were dramatically reduced in juveniles (J2 and J3&4), and markedly increased in adults, when compared with eggs.…”

“…For the habitat conditions, we quantified the relative expression of the fatty acid- and retinol- binding protein gene ( FAR ), which functions to facilitate parasitic nematode infections ( Fairfax et al, 2009 ). For the developmental stage studies, we quantified the relative expression of arginine kinase genes ( AK1 and AK2 ), which have been shown to be differentially expressed at different developmental stages ( Kulathunga et al, 2012 ; Qi et al, 2015 ). Normalization of the two target genes was conducted using the most stable gene combinations ( TUB / 18S rRNA / UBCE or TUB / HIS / 18S rRNA ) and the least stable combinations ( EF/PMP/ACT or ACT/EF/PMP ) as determined by geNorm and RefFinder.…”

Evaluation of an Indirect ELISA Using Recombinant Arginine Kinase for Serodiagnosis of Psoroptes ovis var. cuniculi Infestation in Rabbits

“…It is known to play a crucial role in cellular energy metabolism and maintaining constant ATP levels in invertebrate cells. Data on AKs in parasites are limited to a few reports on Trypanosoma brucei (21), T. cruzi (22), Toxocara canis (23), Haemonchus contortus (24), Teladorsagia circumcincta (25), Ascaris suum (26), Lucilia cuprina , and Ctenocephalides felis (27, 28). Thus, there remain large gaps in our knowledge of AK from parasitic mites.…”

Arginine kinase from Haemonchus contortus decreased the proliferation and increased the apoptosis of goat PBMCs in vitro

“…Arginine kinase (AK), being a highly conserved member of the phosphagen kinase (PKs) family, has been studied extensively with a high degree of sequence similarity among various invertebrate species including H. contortus [5], Trypanosoma cruzi [6], Caenorhabditis elegans [7], Heterodera glycines [8], Toxocara canis and Ascaris lumbricoides [9] and proteobacteria [10]. In invertebrates, AK catalyses the reversible phosphorylation of arginine by MgATP to form phosphoarginine and MgADP [11].…”