Vuong Tan Tu

Description of a new tick species, Ixodes collaris n. sp. (Acari: Ixodidae), from bats (Chiroptera: Hipposideridae, Rhinolophidae) in Vietnam.

BackgroundIn a recent study on ixodid bat ticks from Eurasia, a high genetic difference was found between Ixodes vespertilionis from Europe and Vietnam. Accordingly, it was proposed that I. vespertilionis is a species complex, with at least one additional, hitherto undescribed species. The aim of the present study was to investigate the morphology of bat ticks from Vietnam and to assess their taxonomic status in comparison with those collected in Europe.FindingsIxodid bat ticks (two females and two nymphs) collected from the pomona leaf-nosed bat (Hipposideros pomona) (Hipposideridae) and intermediate horseshoe bat (Rhinolophus affinis) (Rhinolophidae) in Vietnam showed major morphological differences from European isolates of I. vespertilionis, including the shape of the scutum, the enclosure and shape of porose areas, the presence of a caudo-lateral collar-like ridge ventrally on the basis capituli, polytrich coxae with short setae, and grouped (non-linear) arrangement of anterior pit sensillae in Haller’s organ.ConclusionsIn this study the female and the nymph of an ixodid bat tick species from Vietnam are described for the first time. The genetic and morphological differences between I. vespertilionis Koch, 1844 and these bat ticks from Vietnam justify the status of the latter as a distinct species, Ixodes collaris Hornok n. sp.

Cytotoxic and natural killer cell stimulatory constituents of Phyllanthus songboiensis

A dichapetalin-type triterpenoid and a dibenzylbutyrolactone-type lignan, together with five known lignans, a known aromatic diterpenoid, and a known acylated phytosterol, were isolated from the aerial parts of Phyllanthus songboiensis, collected in Vietnam. Their structures were determined by interpretation of the spectroscopic data, and the inhibitory activity toward HT-29 human colon cancer cells of all isolates was evaluated by a cytotoxicity assay. The known arylnaphthalene lignan, (+)-acutissimalignan A, was highly cytotoxic toward HT-29 cells, with an IC50 value of 19 nM, but this compound was inactive as a DNA topoisomerase IIα (topo IIα) poison. The known phytosterol, (-)-β-sitosterol-3-O-β-D-(6-O-palmitoyl)glucopyranoside, was found to stimulate natural killer (NK) cells at a concentration of 10μM in the presence of interleukin 12 (IL-12).

Description of a New Species of the Genus Aselliscus (Chiroptera, Hipposideridae) from Vietnam

Trident bats found in mainland Southeast Asia are currently subsumed into a single species, Aselliscus stoliczkanus. In this study, we examined morphological and genetic data from different populations from Southeast Asia, with a special focus on specimens from Vietnam. Our analyses support the existence of a further species of Aselliscus in northeastern Vietnam that separated from A. stoliczkanus sensu lato (s.l.) during the late Miocene. Within the latter taxon, we identified five geographic lineages that diverged from each other during the Plio-Pleistocene epoch. Some of them may also correspond to further separate taxa, but additional molecular and morphological data are needed to test this hypothesis. Herewith, based on the combined evidences we describe the northeastern Vietnamese population as a separate species.

Mitochondrial gene heterogeneity of the bat soft tick Argas vespertilionis (Ixodida: Argasidae) in the Palaearctic

BackgroundRecently, a high degree of mitochondrial gene heterogeneity was demonstrated between conspecific ixodid ticks of bats in Eurasia. Argas vespertilionis is a soft tick species of mainly vespertilionid bats, also with a wide distribution in the Old World. The aim of this study was to investigate the morphology, mitochondrial gene heterogeneity and host range of A. vespertilionis in the Old World.ResultsAltogether 318 soft tick larvae were collected from 17 bat species (belonging to six genera) in seven countries. Based on the general morphology (setal arrangement) of 314 A. vespertilionis larvae, and the detailed measurements of fifteen larvae, only minor morphological differences (in dorsal plate size and the type of serrate setae) were observed between specimens from Europe and Vietnam. On the other hand, cytochrome c oxidase subunit 1 (cox1) and 16S rRNA gene sequence analyses of 17 specimens showed that A. vespertilionis from Europe is genetically different (with up to 7.5% cox1 and 5.7% 16S rRNA gene sequence divergence) from specimens collected in Vietnam, and their phylogenetic separation is well supported.ConclusionIn its evaluated geographical range, no larval phenotypic differences justify the existence of separate species under the name A. vespertilionis. However, phylogenetic analyses based on two mitochondrial markers suggest that it represents a complex of at least two putative cryptic species. The broad host range of A. vespertilionis might partly explain its lower degree of mitochondrial gene heterogeneity in comparison with ixodid bat tick species over the same geographical region of Eurasia.

First records of Murina lorelieae (Chiroptera: Vespertilionidae) from Vietnam

Abstract In 2011, three specimens from an unknown species of tube-nosed bat (genus Murina) were collected in montane moist forest at altitudes between 1117 and 1682 m in the Ngoc Linh Nature Reserve of Vietnam. We sequenced the mitochondrial COI gene from Ngoc Linh bats and performed comparisons with Murina sequences available in the nucleotide databases. The results suggested that the three unidentified specimens belong to Murina lorelieae, a species recently described from a single specimen collected in southern China. Nucleotide distances between specimens from Ngoc Linh and southern China are exceptionally low for M. lorelieae (1.25%) in comparison with three other Murina species, i.e., Murina cyclotis, Murina feae, and Murina huttoni (3.9–5.5%). We suggest that M. lorelieae is adapted to montane forests, which may have facilitated long-distance dispersal events between southern China and Vietnam during glacial periods of the Pleistocene. Morphological comparisons based on body-size measurements and geometric morphometric analyses of the skulls showed differences between Vietnamese specimens and the Chinese holotype of M. lorelieae. We proposed that the Vietnamese specimens belong to a distinct subspecies, M. lorelieae ngoclinhensis.

A New Species of the Genus Murina (Chiroptera: Vespertilionidae) from the Central Highlands of Vietnam with a Review of the Subfamily Murininae in Vietnam

The subfamily Murininae has high species diversity in Vietnam, but taxonomic studies are limited. In this paper, we describe a new species of the genus Murina based on a specimen collected from Ngoc Linh Nature Reserve, Kon Tum Province in the Central Highlands of Vietnam. It is a medium-sized species with ‘suilla-type’ dentition. A taxonomic review of Murininae from Vietnam was also conducted based on combined morphological, DNA, and karyological characteristics. Molecular phylogenetic analyses based on the mitochondrial cytochrome c oxidase subunit (COI) gene supported the subfamily Murininae, while the genus Murina proved to be paraphyletic in relation to the genera Harpiocephalus and Harpiola. Fourteen species of the genus Murina, one species of Harpiocephalus, and one species of Harpiola are recognized from Vietnam. Murina tiensa is regarded as a junior synonym of M. harrisoni; strong sexual dimorphism was observed in M. harrisoni. Relations between forearm length and total length of skull showed different trends among species and sexes. Karyotypes of Murina huttoni, M. cyclotis, M. lorelieae, M. beelzebub, M. feae, and Harpiola isodon were 2n = 44, FN = 50, while that of Harpiocephalus harpia was 2n = 44, FN = 52.

First Records of Myotis altarium (Chiroptera: Vespertilionidae) from India and Vietnam

Abstract. The Szechwan myotis, Myotis altarium, was first described in 1911 from southeastern China, and for the next 100 years was thought to be restricted to that country with just one additional individual known from Aung Kang region in northern Thailand. We captured eight individuals of this species during surveys in Copia Nature Reserve in northwestern Vietnam and two individuals from East Khasi Hills and East Jaintia Hills districts of Meghalaya state, northeastern India. They are described here as the first records for Vietnam and India. We also provide comparative mensural data including the holotype and other specimens from Southeast Asia. The record of M. altarium from Meghalaya significantly extends the westward distribution range of this species beyond Thailand. Our study affirms previous observations of the cave dwelling habits of M. altarium and suggests that this species temporarily hibernates during cold winter periods in Vietnam. It is also suggested that its distribution range may encompass other karstic habitats in the mainland Indomalayan region.

Molecular investigations of the bat tick Argas vespertilionis (Ixodida: Argasidae) and Babesia vesperuginis (Apicomplexa: Piroplasmida) reflect “bat connection” between Central Europe and Central Asia

Argas vespertilionis is a geographically widespread haematophagous ectoparasite species of bats in the Old World, with a suspected role in the transmission of Babesia vesperuginis. The aims of the present study were (1) to molecularly screen A. vespertilionis larvae (collected in Europe, Africa and Asia) for the presence of piroplasms, and (2) to analyze mitochondrial markers of A. vespertilionis larvae from Central Asia (Xinjiang Province, Northwestern China) in a phylogeographical context. Out of the 193 DNA extracts from 321 A. vespertilionis larvae, 12 contained piroplasm DNA (10 from Hungary, two from China). Sequencing showed the exclusive presence of B. vesperuginis, with 100% sequence identity between samples from Hungary and China. In addition, A. vespertilionis cytochrome oxidase c subunit 1 (cox1) and 16S rRNA gene sequences had 99.1–99.2 and 99.5–100% similarities, respectively, between Hungary and China. Accordingly, in the phylogenetic analyses A. vespertilionis from China clustered with haplotypes from Europe, and (with high support) outside the group formed by haplotypes from Southeast Asia. This is the first molecular evidence on the occurrence of B. vesperuginis in Asia. Bat ticks from hosts in Vespertilionidae contained only the DNA of B. vesperuginis (in contrast with what was reported on bat ticks from Rhinolophidae and Miniopteridae). Molecular taxonomic analyses of A. vespertilionis and B. vesperuginis suggest a genetic link of bat parasites between Central Europe and Central Asia, which is epidemiologically relevant in the context of any pathogens associated with bats.

Highly divergent cyclo-like virus in a great roundleaf bat (Hipposideros armiger) in Vietnam

Members of the viral family Circoviridae are increasingly recognized worldwide. Bats seem to be natural reservoirs or dietary-related dispensers of these viruses. Here, we report a distantly related member of the genus Cyclovirus detected in the faeces of a great roundleaf bat (Hipposideros armiger). Interestingly, the novel virus lacks a Circoviridae-specific stem-loop structure, although a Geminiviridae-like nonamer sequence was detected in the large intergenic region. Based on these differences and its phylogenetic position, we propose that our new virus represents a distant and highly divergent member of the genus Cyclovirus. However it is lacking several characteristics of members of the genus, which raises a challenge in its taxonomic classification.