The complete mitochondrial genome of cattle tick clade C reveals the genetic relationship within Rhipicephalus microplus complex.

Cattle ticks (Rhipicephalus microplus) are important economic ectoparasites causing direct and indirect damage to cattle and leading to severe economic losses in cattle husbandry. It is common knowledge that R. microplus is a species complex including five clades; however, the relationships within the R. microplus complex remain unresolved. In the present study, we assembled the complete mitochondrial genome of clade C by next-generation sequencing and proved its correctness based on long PCR amplification. It was 15,004 bp in length and consisted of 13 protein genes, 22 transfer genes, and two ribosomal genes located in the two strains. There were two copies of the repeat region (pseudo-nad1 and tRNA-Glu). Data revealed that cox1, cox2, and cox3 genes were conserved within R. microplus with small genetic differences. Ka/Ks ratios suggested that 12 protein genes (excluding nad6) may be neutral selection. The genetic and phylogenetic analyses indicated that clade C was greatly close to clade B. Findings in the current study provided more data for the identification and differentiation of the R. microplus complex and made up for the lack of information about R. microplus clade C.

Population genetics and genetic variation of Pomacea canaliculata (Gastropoda: Ampullariidae) in China revealed by sequence analyses of three mitochondrial genes.

The Golden apple snail, Pomacea canaliculata, is one of the world's 100 worst invasive alien species that is best known for its damage to wetland agriculture. It also acts as an intermediate host of some zoonotic parasites such as Angiostrongylus cantonensis, posing threats to human public health and safety. Despite is being an important agricultural pest, the genetic information and population expansion history of this snail remains poorly understood in China. In this study, we analyzed the genetic variation and population genetics of P. canaliculata populations in seven regions of China based on molecular markers of three mitochondrial (mt) genes. A total of 15 haplotypes were recognized based on single mt cox1, nad1, and nad4, and eight haplotypes were identified using the concatenated genes. High haplotype diversity, moderate nucleotide diversity, low gene flow, and high rates of gene differentiation among the seven P. canaliculata populations were detected. Shanghai and Yunnan populations showed higher genetic flow and very low genetic differentiation. The results of Tajima's D, Fu's F s, and mismatch distribution showed that P. canaliculata did not experience population expansion in China. Genetic distance based on haplotypes suggested that nad1 gene was more conserved than cox1 gene within P. canaliculata. The phylogenetic analyses showed there may be two geographical lineages in the Chinese mainland. The present study may provide a new genetic marker to analyze P. canaliculata, and results support more evidence for studying the genetic distribution of P. canaliculata in China and contribute to a deeper understanding of its population genetics and evolutionary biology.

Emerging bacterial infectious diseases/pathogens vectored by human lice.

Human lice have always been a major public health concern due to their vector capacity for louse-borne infectious diseases, like trench fever, louse-borne relapsing fever, and epidemic fever, which are caused by Bartonella quintana, Borrelia recurrentis, and Rickettsia prowazekii, respectively. Those diseases are currently re-emerging in the regions of poor hygiene, social poverty, or wars with life-threatening consequences. These louse-borne diseases have also caused outbreaks among populations in jails and refugee camps. In addition, antibodies and DNAs to those pathogens have been steadily detected in homeless populations. Importantly, more bacterial pathogens have been detected in human lice, and some have been transmitted by human lice in laboratories. Here, we provide a comprehensive review and update on louse-borne infectious diseases/bacterial pathogens.

Characterization of the fragmented mitochondrial genome of domestic pig louse Haematopinus suis (Insecta: Haematopinidae) from China.

The domestic pig louse Haematopinus suis (Linnaeus, 1758) (Phthiraptera: Anoplura) is a common ectoparasite of domestic pigs, which can act as a vector of various infectious disease agents. Despite its significance, the molecular genetics, biology and systematics of H. suis from China have not been studied in detail. In the present study, the entire mitochondrial (mt) genome of H. suis isolate from China was sequenced and compared with that of H. suis isolate from Australia. We identified 37 mt genes located on nine circular mt minichromosomes, 2.9 kb-4.2 kb in size, each containing 2-8 genes and one large non-coding region (NCR) (1,957 bp-2,226 bp). The number of minichromosomes, gene content, and gene order in H. suis isolates from China and Australia are identical. Total sequence identity across coding regions was 96.3% between H. suis isolates from China and Australia. For the 13 protein-coding genes, sequence differences ranged from 2.8%-6.5% consistent nucleotides with amino acids. Our result is H. suis isolates from China and Australia being the same H. suis species. The present study determined the entire mt genome of H. suis from China, providing additional genetic markers for studying the molecular genetics, biology and systematics of domestic pig louse.

Characterization of the complete mitochondrial genome of Culex vishnui (Diptera: Culicidae), one of the major vectors of Japanese encephalitis virus.

Culex mosquitoes (Diptera: Culicidae) can transmit a variety of arthropod-borne viruses (arboviruses), causing human and animal diseases. Cx. vishnui, Cx. pseudovishnui, and Cx. tritaeniorhynchus are three representative species in Culex vishnui subgroup, which are widely distributed in southeast Asia, and they have been proved as the main vectors transmitting Japanese encephalitis virus (JEV) that could cause human infectious mosquito-borne disease across Asia. However, the epidemiology, biology, and even molecular information of those mosquitos remain poorly understood, and only the mitochondrial genome (mitogenome) of Cx. tritaeniorhynchus has been reported in these species. In the present study, we sequenced and annotated the complete mitogenome sequence of Cx. vishnui which was 15,587 bp in length, comprising 37 genes. Comparisons of nucleotide and amino acid sequences between Cx. vishnui and Cx. tritaeniorhynchus revealed that most genes within Culex vishnui subgroup were conserved, except atp8, nad1, atp6, and nad6, with differences of 0.4 (rrnS) - 15.1% (tRNAs) and 0 (nad4L) - 9.4% (atp8), respectively, interestingly suggesting the genes nad4L and rrnS were the most conserved but atp8 gene was the least. The results based on nucleotide diversity also supported a relatively uniform distribution of the intraspecific differences in Cx. vishnui and Cx. tritaeniorhynchus with only one highly pronounced peak of divergence centered at the control region. Phylogenetic analyses using concatenated amino acid sequences of 13 protein-coding genes supported the previous taxonomic classification of the family Culicidae and the monophyly of tribes Aedini, Culicini, Mansoniini, and Sabethini. The present study revealed detailed information on the subgroup Culex vishnui, reanalyzed the relationships within the family Culicidae, provided better markers to identify and distinguish Culex species, and offered more markers for studying the molecular epidemiology, population genetics, and molecular phylogenetics of Cx. vishnui.

Complete bacterial profile and potential pathogens of cat fleas Ctenocephalides felis.

Fleas are important ectoparasites and vectors associated with a wide range of pathogenic diseases, posing threats to public health concerns, especially cat fleas that spread worldwide. Understanding the microbial components is essential due to cat fleas are capable of transmitting pathogens to humans, causing diseases like plague and murine typhus. In the present study, metagenomic next-generation sequencing was applied to obtain the complete microbiota and related functions in the gut of Ctenocephalides felis. A total of 1,870 species was taxonomically recognized including 1,407 bacteria, 365 eukaryotes, 69 viruses, and 29 archaea. Proteobacteria was the dominant phylum among the six samples. Pathogens Rickettsia felis, Acinetobacter baumannii, Coxiella burnetii, and Anaplasma phagocytophilum were taxonomically identified and had high abundances in all samples. The resistance gene MexD was predominant in microbial communities of all cat fleas. We also performed epidemiological surveys of pathogens R. felis, A. baumannii, C. burnetii, and A. phagocytophilum among 165 cat fleas collected from seven provinces in China, while only the DNAs of R. felis (38/165, 23.03%) and C. burnetii (2/165, 1.21%) were obtained. The data provide new insight and understanding of flea intestinal microbiota and support novel information for preventing and controlling fleas and their transmitted diseases.

Morphological and molecular evidence reveals a new species of chewing louse Pancola ailurus n. sp. (Phthiraptera: Trichodectidae) from the endangered Chinese red panda Ailurus styani.

Lice are six-legged, wingless, insect parasites of mammals and birds, and include two main functional groups: blood-sucking lice and chewing lice. However, it is still not clear whether the Chinese red panda Ailurus styani is infested with the parasitic louse. In the present study, we describe a new genus and a species of chewing louse, Pancola ailurus (Phthiraptera: Trichodectidae) based on morphological and molecular datasets. The morphological features showed that Pancola is closer to Paratrichodectes. The genetic divergence of cox1 and 12S rRNA among the Pancola ailurus n. sp. and other Trichodectidae lice was 29.7 - 34.6% and 38.9 - 43.6%, respectively. Phylogenetic analyses based on the available mitochondrial gene sequences showed that P. ailurus n. sp. is more closely related to Trichodectes canis and Geomydoecus aurei than to Felicola subrostratus and together nested within the family Trichodectidae. This study is the first record of parasitic lice from the endangered Chinese red panda A. styani and highlights the importance of integrating morphological and molecular datasets for the identification and discrimination of new louse species.

Aonchotheca (Nematoda: Capillariidae) is validated as a separated genus from Capillaria by both mitochondrial and nuclear ribosomal DNA.

BACKGROUND: The family Capillariidae is a group of thread-like nematodes of 27 genera and over 300 species that infect a great variety of hosts including humans. Among these, some taxa such as the genus Aonchotheca have remained controversial regarding their systematic status for decades. The aim of the current study was to verify Aonchotheca's systemic status and to further determine whether it is a distinct genus from Capillaria using molecular and phylogenetic analyses. RESULTS: We sequenced the mitochondrial (mt) genome and nuclear small subunit (18S) rRNA gene of Aonchotheca putorii, a representative species of the genus, and investigated its systematic status in Trichinellida using maximum likelihood and Bayesian inference. The differences in amino acid sequences of 13 protein-coding genes were 12.69-67.35% among Aonchotheca, Capillaria, Eucoleus, and Pseudocapillaria with cox1 (12.69%) and atp8 (67.35%) as the most and the least conserved gene, respectively, and the difference of two mt rRNAs was 18.61-34.15%. Phylogenetic analyses of the complete mt genome and 18S rRNAs unequivocally showed that Aonchotheca was a distinct genus from Capillaria. CONCLUSIONS: Large difference exists among Aonchotheca, Capillaria, Eucoleus, and Pseudocapillarias. Aonchotheca putorii is the first species in the genus Aonchotheca for which a complete mitogenome has been sequenced. These data are useful for phylogenetics, systematics and the evolution of Capillariidae.

Complete Mitochondrial Genome of Contracaecum Sp. (Nematoda: Ascarididae) from Night Herons in China.

Contracaecum species are zooparasitic anisakid nematodes and occur in gastrointestinal tracts of vertebrate/invertebrate animals, including humans, causing gastrointestinal pain, diarrhea, and increasingly severe vomiting. Although the complete mitochondrial (mt) genome (mitogenome) of Contracaecum sp. isolated from night herons in Beijing has been reported, the detailed information about this mt sequence is still puzzling. In the present study, we described the detailed characteristics across the complete mt DNA of Contracaecum sp., which includes 36 genes consisting of 12 protein genes, 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and 2 noncoding regions (NCRs), and all genes have the same orientation of transcription. The AT content in the complete mitogenome of Contracaecum sp. was 72.2%, and it was the least value (66.7%) in the cox1 gene but was the highest rate (84.1%) in NCRs. The highest nucleotide diversity (Pi) among the genus Contracaecum was nad4 (0.190) and the least was cox1 (0.125), which indicates that nad4 might have the potential ability as useful markers to detect cryptic species in the genus Contracaecum or subspecies. Based on the maximum likelihood (ML) and Bayesian inference (BI) computational algorithms within subfamilies Ascaridoidea and Heterakoidea, the results supported that Contracaecum sp. was a new species and the family Ascaridiidae was paraphyletic. The complete mitogenome sequence of Contracaecum sp. supported a clear recognition of Contracaecum species and provided the potential existence of cryptic species in the genus Contracaecum. Our findings would better contribute to the surveillance, molecular epidemiology, and control of Contracaecum.

Characterization of the complete mitochondrial genome of the fluke of turdus, Plagiorchis elegans, and phylogenetic implications.

Plagiorchis elegans (Trematoda: Digenea) is mainly parasitic in the intestines of vertebrate animals, including humans, causing irreversible pathological damage and herd-spherical influences. However, little information is available about its molecular epidemiology, population genetics, and phylogeny. In the present study, we sequenced, assembled, and annotated the complete mitochondrial (mt) genome of P. elegans. Combining with the available mitochondrial data of subclass Digenea, phylogenetic analysis was performed based on Bayesian inference (BI). These results showed that the complete length of P. elegans is 13,862 bp, including 12 protein-coding genes (PCGs), 2 ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and one non-coding region (NCR). There was an obvious A + T content from 61.0% to 71.3% and the values of the Ka/Ks ratio ranged from 0.119 (cox1) to 1.053 (nad6). In the BI analysis, different from previous studies, phylogenetic analysis showed genus Glypthelmins was paraphyletic rather than monophyletic and had a closer relationship with Plagiorchis and Orientocreadium. Additionally, the BI tree also presented that the genus Echinostoma was monophyletic. Our results provided molecular data in the family Plagiorchiidae proposing new insight within Xiphidiata and Echinostomata.

Comparative Mitochondrial Genomic Analysis Robustly Supported That Cat Tapeworm Hydatigera taeniaeformis (Platyhelminthes: Cestoda) Represents a Species Complex.

Hydatigera taeniaeformis is one of the most common intestinal tapeworms that has a worldwide distribution. In this study, we sequenced the complete mitochondrial (mt) genome of H. taeniaeformis from the leopard cat (designated HTLC) and compared it with those of H. taeniaeformis from the cat in China (designated HTCC) and Germany (designated HTCG). The complete mt genome sequence of HTLC is 13,814 bp in size, which is 167 bp longer than that of HTCC and is 74 bp longer than that of HTCG. Across the entire mt genome (except for the two non-coding regions), the sequence difference was 3.3% between HTLC and HTCC, 12.0% between HTLC and HTCG, and 12.1% between HTCC and HTCG. The difference across both nucleotide and amino acid sequences of the 12 protein-coding genes was 4.1 and 2.3% between the HTLC and HTCC, 13.3 and 10.0% between the HTLC and HTCG, and 13.8 and 10.6% between the HTCC and HTCG, respectively. Phylogenetic analysis based on concatenated amino acid sequences of 12 protein-coding genes showed the separation of H. taeniaeformis from different hosts and geographical regions into two distinct clades. Our analysis showed that the cat tapeworm H. taeniaeformis represents a species complex. The novel mt genomic datasets provide useful markers for further studies of the taxonomy and systematics of cat tapeworm H. taeniaeformis.

Mitochondrial phylogenomics provides insights into the taxonomy and phylogeny of fleas.

BACKGROUND: Fleas (Insecta: Siphonaptera) are obligatory hematophagous ectoparasites of humans and animals and serve as vectors of many disease-causing agents. Despite past and current research efforts on fleas due to their medical and veterinary importance, correct identification and robust phylogenetic analysis of these ectoparasites have often proved challenging. METHODS: We decoded the complete mitochondrial (mt) genome of the human flea Pulex irritans and nearly complete mt genome of the dog flea Ctenocephalides canis, and subsequently used this information to reconstruct the phylogeny of fleas among Endopterygota insects. RESULTS: The complete mt genome of P. irritans was 20,337 bp, whereas the clearly sequenced coding region of the C. canis mt genome was 15,609 bp. Both mt genomes were found to contain 37 genes, including 13 protein-coding genes, 22 transfer RNA genes and two ribosomal RNA genes. The coding region of the C. canis mt genome was only 93.5% identical to that of the cat flea C. felis, unequivocally confirming that they are distinct species. Our phylogenomic analyses of the mt genomes showed a sister relationship between the order Siphonaptera and orders Diptera + Mecoptera + Megaloptera + Neuroptera and positively support the hypothesis that the fleas in the order Siphonaptera are monophyletic. CONCLUSIONS: Our results demonstrate that the mt genomes of P. irritans and C. canis are different. The phylogenetic tree shows that fleas are monophyletic and strongly support an order-level objective. These mt genomes provide novel molecular markers for studying the taxonomy and phylogeny of fleas in the future.

Human pediculosis, a global public health problem.

BACKGROUND: Human pediculosis is caused by hematophagous lice, which are transmitted between individuals via direct and/or indirect contact. Despite the public health importance of louse infestation, information concerning the global burden of pediculosis and the epidemiological landscape of louse-borne diseases is limited. The aim of this review was to summarize the biology, epidemiology, diagnosis, and control of lice infestation in humans. We also discussed the latest advances in molecular taxonomy and molecular genetics of lice. METHODS: We searched five electronic bibliographic databases (PubMed, ScienceDirect, CNKI, VIP Chinese Journal Database, and Wanfang Data) and followed a standard approach for conducting scoping reviews to identify studies on various aspects of human lice. Relevant information reported in the identified studies were collated, categorized, and summarized. RESULTS: A total of 282 studies were eligible for the final review. Human pediculosis remains a public health issue affecting millions of people worldwide. Emerging evidence suggests that head lice and body lice should be considered conspecific, with different genotypes and ecotypes. Phylogenetic analysis based on mitochondrial (mt) cytb gene sequences identified six distinct clades of lice worldwide. In addition to the direct effect on human health, lice can serve as vectors of disease-causing pathogens. The use of insecticides plays a crucial role in the treatment and prevention of louse infestation. Genome sequencing has advanced our knowledge of the genetic structure and evolutionary biology of human lice. CONCLUSIONS: Human pediculosis is a public health problem affecting millions of people worldwide, particularly in developing countries. More progress can be made if emphasis is placed on the use of emerging omics technologies to elucidate the mechanisms that underpin the physiological, ecological, and evolutionary aspects of lice.

Comparative analyses of the mitochondrial genomes of the cattle tick Rhipicephalus microplus clades A and B from China.

The cattle tick (Rhipicephalus microplus) is one of the most common ticks parasitizing livestock, causing diseases as the vector of pathogens. In this study, we amplified and sequenced the complete mitochondrial (mt) genome of R. microplus from Hainan province of China and compared it with that of R. microplus from Guizhou province of China. The mt genome sequence of R. microplus from Hainan isolate was 15,163 bp in size, which was significantly longer (299 bp) than R. microplus from Guizhou isolate. Nucleotide sequence difference in the entire mt genome except for non-coding region was 5.6% between R. microplus from Hainan and Guizhou isolates. For the 13 protein-coding genes, this comparison revealed the sequence differences of nucleotide (3.8-10.1%) and amino acid (1.2-17.3%). Phylogenetic analysis of R. microplus indicated that R. microplus from Hainan isolate clustered in clade A, and R. microplus from Guizhou isolate clustered in clade B. Taken together, the findings support the recent proposal the existence of two lineages (clades A and B) of R. microplus in China.

Metagenomics of the midgut microbiome of Rhipicephalus microplus from China.

BACKGROUND: Ticks, which are ectoparasites of animals, may carry multiple pathogens. The cattle tick Rhipicephalus microplus is an important bovine parasite in China. However, the midgut microbiome of R. microplus from China has not been characterized via metagenomic methods. METHODS: Rhipicephalus microplus were collected from cattle in the city of Changsha in Hunan province, China. The DNA of the midgut contents was extracted from fully engorged adult female R. microplus. A DNA library was constructed and sequenced using an Illumina HiSeq sequencing platform. SOAPdenovo software was used to assemble and analyze the clean data. The latent class analysis algorithm applied to system classification by MEGAN software was used to annotate the information on the species' sequences. DIAMOND software was used to compare unigenes with the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and functional annotation was carried out based on the results of the comparison. RESULTS: The dominant phyla in the five samples were Firmicutes, Proteobacteria, and Actinobacteria. Streptococcus, Mycobacterium, Anaplasma, Enterococcus, Shigella, Lactobacillus, Brachyspira, Pseudomonas, Enterobacter, Bacillus, and Lactococcus were the dominant genera in the five samples. The endosymbiotic bacterium Wolbachia was also detected in all of the samples. Mycobacterium malmesburyense, Streptococcus pneumoniae, Anaplasma phagocytophilum, Enterococcus faecium, Shigella sonnei, Enterococcus faecalis, Lactobacillus casei, Brachyspira hampsonii, Pseudomonas syringae, Enterobacter cloacae, and Lactococcus garvieae were the dominant species in the five samples. In addition to these bacterial species, we also detected some eukaryotes, such as Rhizophagus irregularis, Enterospora canceri, Smittium culicis, Zancudomyces culisetae, Trachipleistophora hominis, and viruses such as orf virus, human endogenous retrovirus type W, enzootic nasal tumor virus of goats, bovine retrovirus CH15, and galidia endogenous retrovirus in all of the samples at the species level. The results of the annotated KEGG pathway predictions for the gene functions of the midgut microflora of R. microplus indicated genes involved in lipid and amino acid metabolism, infectious diseases (e.g., Streptococcus pneumonia infection, human granulocytic anaplasmosis, Shigella sonnei infection, Salmonella enterica infection, and pathogenic Escherichia coli infection), and cancer. CONCLUSIONS: Our study revealed that the midgut microbiome of R. microplus is not only composed of a large number of bacteria, but that a portion also comprises eukaryotes and viruses. The data presented here enhance our understanding of this tick's midgut microbiome and provide fundamental information for the control of ticks and tick-borne diseases.

The complete mitochondrial genome of capillariid nematodes (Eucoleus annulatus): A novel gene arrangement and phylogenetic implications.

Capillariid nematode is a group of endoparasites of vertebrates with a complex taxonomy, causing significant economic losses to poultry industry. The taxonomic status of the genus Eucoleus remained controversial for several decades. Mitochondrial (mt) DNA provides useful genetic markers for accurate identification of species, but complete mt genome sequences have been lacking for any Capillariid nematodes. In the present study, we decoded the complete mt genome of E. annulatus and examined its phylogenetic relationship with selected members of the class Enoplea nematodes. The circular mt genome of E. annulatus was 14,118 bp, encoded 37 genes with a single non-coding region and showed substantial gene rearrangements (especially tRNA genes) compared to other nematodes studied to date. The complete mt genome of E. annulatus showed a clear A + T bias in nucleotide composition. The number of A (5404) was approximately equal to T (5405) and the GC-skew was negative on average (-0.073). Phylogenetic analyses based on 18S rDNA placed Eucoleus spp. well apart from each other and supported the proposal that Eucoleus and Capillaria are two distinct genera. Similarly, Bayesian inference (BI) and Maximum likelihood (ML) phylogenies based on mtDNA sequences revealed that the family Capillariidae is more closely related to the family Trichuridae than to the family Trichinellidae. This is the first report of the complete mt genome of capillariid nematodes, and it will provide additional genetic markers for studying the molecular epidemiology, population genetics and systematics of capillariid nematodes and should have implications for the molecular diagnosis, prevention, and control of capillariosis in animals.

Characterization of the complete mitochondrial genome of the swine kidney worm Stephanurus dentatus (Nematoda: Syngamidae) and phylogenetic implications.

Swine stephanuriasis caused by kidney worm Stephanurus dentatus is a parasitic disease in tropical and subtropical countries, leading to economic losses. Despite its significance as a pathogen, the phylogenetic position and taxonomic status of this nematode remain poorly understood. Mitochondrial (mt) genome sequences are known to provide useful genetic markers for investigations in these areas, but mt genome sequences are lacking for S. dentatus. In the present study, we determined the complete mt genome sequences of S. dentatus with an Illumina platform and compared it with the mt genomes of other closely related species. The circular mt genome was 13,735 bp in size with 36 genes. All genes are transcribed in the same direction and the mt gene arrangement is identified as a GA3 pattern, that is the most common pattern of gene arrangement observed in nematodes to date. Phylogenetic analysis using concatenated amino acid sequences of 12 protein-coding genes supported the hypothesis that S. dentatus was closely related to the family Chabertiidae. Our results provided insights into the phylogenetic relationship of the family Syngamidae within the superfamily Strongyloidea.

Highly rearranged mitochondrial genome in Falcolipeurus lice (Phthiraptera: Philopteridae) from endangered eagles.

BACKGROUND: Fragmented mitochondrial (mt) genomes and extensive mt gene rearrangements have been frequently reported from parasitic lice (Insecta: Phthiraptera). However, relatively little is known about the mt genomes from the family Philopteridae, the most species-rich family within the suborder Ischnocera. METHODS: Herein, we use next-generation sequencing to decode the mt genome of Falcolipeurus suturalis and compare it with the mt genome of F. quadripustulatus. Phylogenetic relationships within the family Philopteridae were inferred from the concatenated 13 protein-coding genes of the two Falcolipeurus lice and members of the family Philopteridae using Bayesian inference (BI) and maximum likelihood (ML) methods. RESULTS: The complete mt genome of F. suturalis is a circular, double-stranded DNA molecule 16,659 bp in size that contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and three non-coding regions. The gene order of the F. suturalis mt genome is rearranged relative to that of F. quadripustulatus, and is radically different from both other louse species and the putative ancestral insect. Phylogenetic analyses revealed clear genetic distinctiveness between F. suturalis and F. quadripustulatus (Bayesian posterior probabilities = 1.0 and bootstrapping frequencies = 100), and that the genus Falcolipeurus is sister to the genus Ibidoecus (Bayesian posterior probabilities = 1.0 and bootstrapping frequencies = 100). CONCLUSIONS: These datasets help to better understand gene rearrangements in lice and the phylogenetic position of Falcolipeurus and provide useful genetic markers for systematic studies of bird lice.

The complete mitochondrial genome sequences of the cat flea Ctenocephalides felis felis (Siphonaptera: Pulicidae) support the hypothesis that C. felis isolates from China and USA were the same C. f. felis subspecies.

The cat flea Ctenocephalides felis (Siphonaptera: Pulicidae) is the most important ectoparasite in cats and dogs worldwide. Over the years, there has been much dispute regarding the taxonomic and systematic status of C. felis. Mitochondrial (mt) genome sequences are useful genetic markers for the identification and differentiation of ectoparasites, but the mt genome of C. felis and its subspecies has not yet been entirely characterized. In the present study, the entire mt genome of C. f. felis from China was sequenced and compared with that of C. felis from the USA. Both contain 37 genes and a long non-coding region of >6 kbp. The molecular identity between the Chinese and American isolates was 99%, except for the non-coding region. The protein-coding genes showed differences at both the nucleotide (1.2%) and amino acid (1%) levels. Interestingly, the cox1 gene of the Chinese isolate had an unusual putative start codon (TTT). Taken together, our analyses strongly support the hypothesis that C. felis isolates from China and the USA were the same C. f. felis subspecies. The mt genome sequence of the C. f. felis China isolate presented in this study provides useful molecular markers to further address the taxonomy and systematics of C. felis.

Screening Study on the Anti-Angiogenic Effects of Traditional Chinese Medicine - Part II: Wild Chrysanthemum.

Background and Aims: Part 2 of our ongoing research with anti-angiogenic effects focuses on Wild chrysanthemum; a heat-clearing and detoxicating Traditional Chinese Medicine (TCM). We screened six heat-clearing and detoxicating TCM and noticed that wild chrysanthemum has a potent anti-angiogenic effect in zebrafish. This study aims to determine the genetic mechanisms underlying the anti-angiogenic effects of wild chrysanthemum. Methods: Wild chrysanthemum was decocted, concentrated, sieved and desiccated to attain the water extract. 200µg/mL wild chrysanthemum water extract (WCWE) was diluted in 0.1% dimethyl sulfoxide (DMSO) and given to zebrafish via fish water. 48h post-fertilization (hpf) fli1a-EGFP transgenic zebrafish were used to assay angiogenesis. mRNA-seq, qRT-PCR assay and a parallel reaction monitor (PRM) were carried out to reveal the underlying mechanisms. Results: WCWE showed a significant anti-angiogenic effect in zebrafish. The results of mRNA-seq showed that there were 1119 genes up-regulated and 1332 genes down-regulated by WCWE. The bioinformatic analysis based on mRNA-seq demonstrated that the proteasome signaling pathway was significantly down-regulated. The results of the qRT-PCR assay were consistent with those of the mRNA-seq assay. The results of the PRM assay showed that nine proteins involved in proteasome signaling and the protein expression level of ctnnb2 were significantly down-regulated. The results of the KEGG pathway analysis based on PRM assay demonstrated that WCWE may have an inhibitory action on the regulatory particle of the proteasome. Conclusion: Wild chrysanthemum has a significant anti-angiogenic effect in zebrafish and it may have an inhibitory action on the regulatory particle of the proteasome. The mechanisms underlying the anti-angiogenic effects of wild chrysanthemum may be related to the down-regulation of proteasome/ß-catenin signaling in zebrafish.