Phylogeographic genetic variation of Indoplanorbis exustus (Deshayes, 1834) (Gastropoda: Planorbidae) in South and Southeast Asia

The freshwater snail Indoplanorbis exustus play an important role as the sole intermediate host of several medically- and economically-important trematodes, especially zoonotic schistosomes and echinostomes, which can infect and cause diseases in livestock and people. This study aims to explore the mitochondrial cytochrome c oxidase subunit 1 sequence variation of I. exustus collected from new geographical areas; 459 specimens of I. exustus were collected from 43 localities in South and Southeast Asia. The 42 haplotypes (Ie1 - Ie42) we detected were classified into haplogroups I - V. Phylogenetic analyses revealed five major clades, A - E, in concordance with all previous studies. Clade E contained two subclades, E1 (haplogroup I) and E2 (haplogroup II). The most widespread genetic group was subclade E1. Clade A, clade B (haplogroup V), and clade C (haplogroup IV) were found only in South Asia, whereas clade D (haplogroup III) was specifically found in Southeast Asia. In Thailand, I. exustus showed high genetic divergence with 21 haplotypes. Several isolates showed significant genetic differences from others with unique haplotype(s). Hence, we confidently conclude our findings support all previous studies that I. exustus is a species complex with at least four major lineages and five haplogroups. Our additional analyses of 35 samples from Sri Lanka showed these were indeed an independent genetic group as previously found, but they can now be classified as a unique group forming subclade E2 (haplogroup II) of I. exustus sensu lato.

Preliminary screening of the aqueous extracts of twenty-three different seaweed species in Sri Lanka with in-vitro and in-vivo assays

Background

Seaweeds are an important source of bioactive compounds which are applied in various aspects of medicinal investigations. The present study was conducted to investigate cytoxicity (in-vitro and in-vivo) and wound healing activity of different seaweed species in Sri Lanka.

Methods

Twenty-three seaweed samples, belonging to Phaeophyta (Brown), Chlorophyta (Green) and Rhodophyta (Red) were used for the experiments. Samples were collected from the inter-tidal and the sub-tidal habitats around Sri Lankan coast (Southern, Northern and North-western). Aqueous seaweed extracts were tested for cytotoxic and wound healing activity; in-vitro and in-vivo. To determine toxicity of aqueous seaweed extracts, brine shrimp lethality assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay on mouse fibroblasts (L929) cell line were performed. Cell migration induction of seaweed extracts was assessed by scratch wound healing assay using L929 cell line. Based on the our previous experiments S.ilicifolium (SW23) was selected for the in vivo study to confirm our hypothesis. Albino mice (BALB/c) were divided into three groups (12 in each) and a circular area (44.07 ± 02.51 mm²) of full skin was excised to create a wound in mice group II and III. Group III received aqueous extract of Sargasum illicifolium (400 mg/kg BW/day for 12 days, orally), Group II received distilled water for 12 days whereas Group I was used as the control group and it was tested without forming wounds and without providing any treatment. Further, the expression level of Tumor Necrosis Factor (TNF-α) and Transforming Growth Factor-β (TGF-β) via RT-PCR were measured every three days until the end of the experiment.

Results

Phytochemical tests showed positive results to flavonoids in all the selected green seaweeds and alkaloids were observed in red seaweeds. In the toxicity assay, red seaweed, Acanthophora spicifera (SW17) was found to be highly effective on nauplii of brine shrimp (LC₅₀ = 0.072 μg/μl). LC₅₀ value of green seaweed species, Caulerpa racemosa (SW02 and SW08) and Caulerpa sertularioides (SW10) was not found within the tested concentration series. The highest cytotoxic effect on L929 cell line was exhibited by aqueous extracts of red seaweed; Jania adhaereus with 50.70 ± 7.304% cell viability compared with control group. The highest cell migration activity was observed in L929 cell line group treated with extracts of green seaweed namely; Halimeda opuntin (SW07) and extracts of brown seaweed namely; Stoechospermum polypodioides (SW11). Extracts of S. illicifolium (SW23) exhibited a significantly enhanced wound healing activity in mice group III within three days (P < 0.05) with an open wound area of 17.35 ± 1.94 mm² compared with control group (26.29 ± 2.42 mm²). TGF-β gene expression peaked on 6^th day of post-wound and subsequently decreased on 9^th day of post-wound in mice group III. TNF-α expression was suppressed in mice group III whereas it was elevated in group II. TGF-β expression is enhanced in the treatment group compared to the control group.

Conclusions

Aqueous extracts of selected seaweeds are a significant source of potential compounds with wound healing properties, which might be helpful in the healing of various wounds. This also infers that many species of brown and red seaweeds have the potential of wound healing, specifically, Sargasum illicifolium and Jania adhaereus could be a potential candidate for in-vivo studies related to wound healing and cancer therapy in the near future.

Characterization and phylogenetic properties of the complete mitochondrial genome of Fascioloides jacksoni (syn. Fasciola jacksoni) support the suggested intergeneric change from Fasciola to Fascioloides (Platyhelminthes: Trematoda: Plagiorchiida)

Fascioloides jacksoni (syn. Fasciola jacksoni, Cobbold, 1869) (Platyhelminthes: Echinostomatoidea), is a liver fluke that causes severe morbidity and mortality of Asian elephants (Elephas maximus maximus). Understandings on molecular diagnosis, epidemiology, genetics and evolution of this flatworm are limited. In this study, we present the complete mitochondrial DNA (mt) sequence of 14,952 bp obtained from an individual fluke and comparative characterization of mitogenomic features with fasciolids, primarily, Fascioloides magna and other taxa in the superfamily Echinostomatoidea. Taxonomic relationship within and between Echinostomatoidea, Opisthorchioidea and Paramphistomoidea in the order Plagiorchiida, are also taxonomically considered. The complete circular mt molecule of Fas. jacksoni contained 12 protein-coding, two ribosomal RNA, 22 transfer RNA genes, and a non-coding region (NCR) rich in tandem repeat units. As common in digenean trematodes, Fas. jacksoni has the usual gene order, the absence of atp8 and the overlapped region by 40 bp between nad4L and nad4 genes. The NCR located between tRNA^Glu (trnE) and cox3 contained nine nearly identical tandem repeat units (TRs of 113 bp each). Special DHU-arm missing tRNAs for Serine were found for both, tRNA^S1(AGN) and tRNA^S2(UCN). Base composition indicated that cox1 of Fas. jacksoni showed the lowest (11.8% to Fas. magna, 12.9 - 13.6% to Fasciola spp. and 18.1% to Fasciolopsis buski) and nad6 the highest divergence rate (19.2%, 23.8-26.5% and 27.2% to each fasciolid group), respectively. A clear bias in nucleotide composition, as of 61.68%, 62.88% and 61.54%, with a negative AT-skew of the corresponding values (-0.523, -0.225 and - 0.426) for PCGs, MRGs and mtDNA for Fas. jacksoni and likewise data for the fasciolids. Phylogenetic analysis confirmed the sister branch of Fas. jacksoni and Fas. magna with the nodal support of 100%, clearly separated from the taxonomically recognized Fasciola spp. With the previous studies, mitogenomic data presented in this study are strongly supportive for Fasciola jacksoni reappraisal as Fascioloides jacksoni in the Fascioloides genus.