Molecular phylogenetic analysis of Echinococcus multilocularis from horses raised in Canada or Japan, using mitochondrial cytochrome b gene-targeted PCR

Alveolar echinococcosis is a zoonotic disease caused by a larval-stage Echinococcus multilocularis infection. Geographical haplotyping targeting the parasite's mitochondrial cytochrome b (cob) gene has been reported for isolates from definitive and intermediate hosts (wild canids and rodents); however, there are limited reports on strain typing for the dead-end host, the horse, which could act as a sentinel for E. multilocularis. Accordingly, we investigated the diversity of E. multilocularis in isolates obtained from slaughtered Japanese and Canadian horses originating from the Iburi and Hidaka regions in Hokkaido and from Alberta, respectively, with PCR and haplogroup analyses targeting cob gene sequences obtained. Seventy horses were diagnosed with alveolar echinococcosis based on histopathology and cob-gene PCR testing. The E. multilocularis detected in these horses was classified as either an Asian (for Hokkaido-raised horses) or a European (for Alberta-raised horses) haplogroup, based on the obtained cob-gene sequence analysis. In addition, haplotype network analysis revealed that E. multilocularis isolated from Hokkaido-raised horses is highly homologous to Kazakhstan isolates, and E. multilocularis isolated from Alberta-raised horses is highly homologous to Austrian isolates. The results of this study suggest that cob-gene-targeted PCR analysis could be useful for the geographical genetic characterization of E. multilocularis isolated from horses.

Newly developed SYBR Green-based quantitative real-time PCRs revealed coinfection evidence of Angiostrongylus cantonensis and A. malaysiensis in Achatina fulica existing in Bangkok Metropolitan, Thailand

Angiostrongylus cantonensis is a well-known pathogen causing eosinophilic meningitis associated with angiostrongyliasis. Humans, as accidental hosts, are infected by consuming undercooked snails containing third-stage larvae. A. malaysiensis is closely related to A. cantonensis and has been described as a potential human pathogen. The two species distribution was recently reported to overlap in the same endemic area, particularly in the Indochina Peninsula. Similar morphological characteristics of the third-stage larva in the snail-intermediate host often lead to misidentification of the two species. Thus, we aimed to develop a sensitive and specific method to detect and discriminate Angiostrongylus third-stage larva by designing species-specific primers based on the mitochondrial cytochrome b gene. We developed the SYBR Green quantitative real-time PCR (qPCR) method for two species-specific detection assays, which could be conducted simultaneously. The method was subsequently employed to detect and identify third-stage larvae of Angiostrongylus isolated from infected Achatina fulica collected from six public parks in Bangkok Metropolitan, Thailand. The method was also a preliminary applied to detect parasite tissue debris in the patients' cerebrospinal fluid (CSF). SYBR Green qPCRs quantitatively detected approximately 10⁻⁴ ng of genomic DNA from one larva, facilitating species-specific detection. Based on the pools of third-stage larvae isolated individually from the tissue of each infected A. fulica collected from the public parks, the qPCR results revealed that A. malaysiensis was the predominant species infecting 5.26% of the collected snails. In comparison, coinfection between A. malaysiensis and A. cantonensis was 5.97%, and no single infection of A. cantonensis was detected in A. fulica. Our SYBR Green qPCR method is a useful and inexpensive technique for A. cantonensis and A. malaysiensis discrimination, and the method has sufficient sensitivity to detect isolated larvae from a snail-intermediate host. The ratio of A. cantonensis and A. malaysiensis larvae infecting the snails can also be estimated simultaneously. Our qPCRs can be employed in a molecular survey of A. cantonensis and A. malaysiensis within intermediate hosts and for clinical diagnosis of angiostrongyliasis with CSF specimens in future studies.

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The SYBR Green qPCRs were developed to detect and discriminate Angiostrongylus third-stage larvae by designing species-specific primers based on the mitochondrial cytochrome b gene.

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A. malaysiensis is the predominant species in Bangkok Metropolitan, Thailand.

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Coinfection between A. cantonensis and A. malaysiensis has occurred in the Achatina fulica population in Bangkok

High prevalence and genetic diversity of Haemoproteus columbae (Haemosporida: Haemoproteidae) in feral pigeons Columba livia in Cape Town, South Africa

In this study, we explore blood parasite prevalence, infection intensity, and co-infection levels in an urban population of feral pigeons Columba livia in Cape Town. We analyze the effect of blood parasites on host body condition and the association between melanin expression in the host's plumage and parasite infection intensity and co-infection levels. Relating to the haemosporidian parasite itself, we study their genetic diversity by means of DNA barcoding (cytochrome b) and show the geographic and host distribution of related parasite lineages in pigeons worldwide. Blood from 195 C. livia individuals was collected from April to June 2018. Morphometric measurements and plumage melanism were recorded from every captured bird. Haemosporidian prevalence and infection intensity were determined by screening blood smears and parasite lineages by DNA sequencing. Prevalence of Haemoproteus spp. was high at 96.9%. The body condition of the hosts was negatively associated with infection intensity. However, infection intensity was unrelated to plumage melanism. The cytochrome b sequences revealed the presence of four Haemoproteus lineages in our population of pigeons, which show high levels of co-occurrence within individual birds. Three lineages (HAECOL1, COLIV03, COQUI05) belong to Haemoproteus columbae and differ only by 0.1% to 0.8% in the cytochrome b gene. Another lineage (COLIV06) differs by 8.3% from the latter ones and is not linked to a morphospecies, yet. No parasites of the genera Leucocytozoon and Plasmodium were detected.

Glycogen synthase kinase-3 (GSK3) controls deoxyglucose-induced mitochondrial biogenesis in human neuroblastoma SH-SY5Y cells

Mitochondrial biogenesis, a mitochondrial growth and division process, is crucial for adaptation to metabolic stress. The present study demonstrated that treatment with a specific inhibitor of GSK3, SB216763, attenuated induction of mitochondrial biogenesis by a glycolysis inhibitor, 2-deoxyglucose (2-DG), without affecting this biogenesis at basal condition. Additionally, overexpression of WT-GSK3β promoted whereas GSK3β-KD attenuated 2-DG-induced mitochondrial protein expression. The mitochondrial biogenesis attenuation by GSK3 inhibitor was not due to inhibition of protein degradation. Furthermore, GSK3 inhibition further reduced transcription of mitochondrial (COXII), but not nuclear (VDAC) gene by 2-DG suggesting its participation in 2-DG-induced mitochondrial transcription. Together, our results show that GSK3 regulates mitochondrial biogenesis induced by glycolysis inhibition.

Respiratory complex III dysfunction in humans and the use of yeast as a model organism to study mitochondrial myopathy and associated diseases

The bc1 complex or complex III is a central component of the aerobic respiratory chain in prokaryotic and eukaryotic organisms. It catalyzes the oxidation of quinols and the reduction of cytochrome c, establishing a proton motive force used to synthesize adenosine triphosphate (ATP) by the F1Fo ATP synthase. In eukaryotes, the complex III is located in the inner mitochondrial membrane. The genes coding for the complex III have a dual origin. While cytochrome b is encoded by the mitochondrial genome, all the other subunits are encoded by the nuclear genome. In this review, we compile an exhaustive list of the known human mutations and associated pathologies found in the mitochondrially-encoded cytochrome b gene as well as the fewer mutations in the nuclear genes coding for the complex III structural subunits and accessory proteins such as BCS1L involved in the assembly of the complex III. Due to the inherent difficulties of studying human biopsy material associated with complex III dysfunction, we also review the work that has been conducted to study the pathologies with the easy to handle eukaryotic microorganism, the yeast Saccharomyces cerevisiae. Phenotypes, biochemical data and possible effects due to the mutations are also discussed in the context of the known three-dimensional structure of the eukaryotic complex III. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.