Biology subjects

Kanuka, H.

Publications and source records attributed to Kanuka, H..

5 recordsLinked to original sources

bioRxiv2025

A chromosome-level genome resource for the lethal tapeworm Sparganum proliferum, with candidate genomic safe harbours for functional genetics

Sparganum proliferum is an enigmatic and highly proliferative cestode known for its ability to form invasive larval infections in mammalian hosts. Here, we present the first chromosome-level genome assembly for a member of the order Diphyllobothriidea, generated using a hybrid sequencing approach that integrates Oxford Nanopore/PacBio long-read sequencing, Illumina short-read sequencing, and Hi-C scaffolding. The final genome assembly spanned approximately 681 megabases (Mb) across nine chromosomes. BUSCO analysis revealed 81.9% completeness, whereas repeat annotation identified 55.8% of the genome as repetitive elements. Gene annotation uncovered approximately 29,000 protein-coding genes including [~]6200 transposon associated genes, highlighting the complex genomic landscape underlying parasitic lifestyles. Synteny analysis with other cestode linages including Echinococcus and Hymenolepis provided insights into the structural organisation and evolutionary trajectory of S. proliferum. In addition, we identified candidate genomic safe harbour (GSH) loci and promoters from housekeeping genes, offering potential for stable transgene integration. This high-quality genome serves as a critical resource for studying parasite evolution, host adaptation mechanisms, and the molecular basis of invasive proliferation in cestodes.

genomics↗

bioRxiv2024

Three years of insecticide resistance evolution and associated mechanisms in Aedes aegypti populations of Ouagadougou, Burkina Faso.

BackgroundResistance to insecticides is spreading among populations of Aedes aegypti, the primary vector of important human arboviruses. The escalating insecticide resistance poses a significant threat to dengue vector control, with an expanding number of countries affected by the disease. To gain a deeper insight into the evolution of insecticide resistance, it is essential to have longitudinal surveillance results, which are currently lacking, particularly from African Ae. aegypti populations. Here we report on three-years of surveillance of Ae. aegypti susceptibility to insecticide resistance phenotypes and associated kdr mutations in Burkina Faso, a country with regular dengue outbreaks. MethodsAe. aegypti susceptibility to insecticides and the V410L, V1016I, and F1534C kdr target site mutations linked to pyrethroid insecticide resistance were monitored in Ouagadougou from 2016 to 2018. Larvae were collected from artificial containers at two sites and reared to adulthood in an insectary. Bioassays were conducted on female adults, alongside with a laboratory-susceptible strain, following standard WHO protocols. Allele-specific PCR genotyping assays were utilized to identify the V410L, V1016I, and F1534C kdr pyrethroid target site mutations. ResultsBioassays revealed a high level of resistance to permethrin and deltamethrin that progressively increased over the three-year period in both localities. The 1534C mutation was nearly fixed throughout the three years at each locality, and while the closely related 410L and 1016I mutations did not vary between localities, their frequency notably increased from 2016 to 2018. Interestingly, Ae. aegypti populations in both areas remained susceptible to bendiocarb, fenitrothion, and malathion. Modeling the mortality data further confirmed the escalating resistance trend over the years and emphasized the significant role played by the three kdr mutations in conferring resistance to pyrethroids. ConclusionMortality rates indicate that Ae. aegypti populations from Ouagadougou are becoming increasingly resistant to pyrethroid insecticides, likely due to an increase in the frequencies of the 410L and 1016I kdr mutations. Organophosphate insecticides are likely to be better alternative options for control.

evolutionary biology↗

bioRxiv2024

Wolbachia infection in Aedes aegypti does not affect its vectorial capacity for Dirofilaria immitis

Mosquito-borne diseases such as dengue and filariasis are a growing public health concern in endemic countries. Biological approaches, such as the trans-infection of Wolbachia pipientis in mosquitoes, are an alternative vector control strategy, especially for arthropod-borne viruses such as dengue. In the present study, the effect of Wolbachia (wMel strain) on the vectorial capacity of Aedes aegypti for Dirofilaria immitis was studied. Our results showed that Wolbachia does not affect the phenotype of mosquito survival or the prevalence, number, and molting rate of third-stage larvae in both susceptible and resistant strains of Ae. aegypti. RNA-seq analysis of Malpighian tubules at 2 days post-infection with D. immitis showed the differentially expressed genes (DEGs) with and without wMel infection. No characteristic immune-related gene expression patterns were observed among the DEGs. No significant change in the amount of Wolbachia was observed in the Ae. aegypti after D. immitis infection. Our results suggest that infection of D. immitis in Ae. aegypti populations will not interfere with Wolbachia-based vector control strategies in dengue-endemic areas where cases of D. immitis are present. This study demonstrated the veterinary medical validity of a dengue control program using Wolbachia.

microbiology↗

bioRxiv2023

DIPA-CRISPR gene editing in the yellow fever mosquito Aedes aegypti (Diptera: Culicidae)

Current methods for gene editing in insects rely on embryonic microinjection, which can be challenging for non-specialist laboratories. Recently, an alternative method known as "direct parental" CRISPR (DIPA-CRISPR) was developed. This method involves injecting commercial Cas9 protein and single-guide RNA into adult females, which can efficiently introduce mutations into developing oocytes. However, its versatility has not been fully explored, particularly in insects that have the most derived, polytrophic meroistic ovaries. In this study, we successfully applied DIPA-CRISPR to the yellow fever mosquito Aedes aegypti, which has polytrophic meroistic ovaries. Following adult injection of Cas9 ribonucleoproteins (Cas9 RNPs) targeting the kynurenine 3-monooxygenase gene, we recovered gene-edited G0 individuals. Injection at 24 h after blood-feeding resulted in the highest gene editing efficiency (3.5%), confirming that a key parameter of DIPA-CRISPR is the stage in which the adult females are injected. Together with our previous study, we demonstrated that DIPA-CRISPR is applicable to all three types of insect ovaries (i.e., panoistic, telotrophic, and polytrophic), which indicates that DIPA-CRISPR is a generalizable approach for insect gene editing.

genetics↗

bioRxiv2021

Severe fever with thrombocytopenia syndrome virus and parthenogenetic Asian longhorned tick Haemaphysalis longicornis (Acari: Ixodidae)

Severe fever with thrombocytopenia syndrome virus (SFTSV) is spreading rapidly in Asia. It is transmitted by Haemaphysalis longicornis (Asian longhorned tick, ALT), which has both parthenogenetically and sexually reproducing populations. Parthenogenetic populations were found in at least 15 provinces in China and strongly correlated with the distribution of SFTS. The distribution of SFTS cases was however poorly correlated with the distribution of populations of bisexual ALTs. Phylogeographic analysis suggested that the parthenogenetic population spread much faster than bisexual population because colonization is independent of sexual reproduction. A higher proportion of parthenogenetic ALTs were collected from migratory birds captured at an SFTS endemic area, implicating the contribution to the long-range movement of ALTs in China. The SFTSV susceptibility of parthenogenetic females was like that of bisexual females under laboratory conditions. These results suggest that parthenogenetic ALT, probably transported by migratory birds, play a major role in the rapid spread of SFTSV. Article Summary LineThe parthenogenetic population of Asian longhorned tick is broadly distributed in China and plays a major role in the long-distance spread of SFTSV and perhaps future invasion of countries outside of Asia.

evolutionary biology↗