Mitochondrial CO1 Gene Research Articles

David versus Goliath: An interspecific comparison between small-sized Halicryptus spinulosus and large-sized Halicryptus higginsi (Priapulida)

Halicryptus includes two priapulid species with highly different adult body sizes, small-sized Halicryptus spinulosus von Siebold, 1849 and large-sized Halicryptus higginsi Shirley and Storch, 1999. Due to ambiguity of diagnostic characters from juvenile to adult size and between species, a detailed morphological and molecular comparison is needed to resolve the distribution and characteristics of each species. We investigate an adult paratype specimen of H. higginsi, and young adult specimens of H. spinulosus from the Beaufort Sea and H. spinulosus from Kandalaksha Gulf, White Sea. Molecular analysis of the mitochondrial CO1 gene confirm the existence of two species of Halicryptus, a wide distribution of H. spinulosus across the Northern Hemisphere and the co-occurrence of both species in the Beaufort Sea. Our morphological analyses reveal undocumented characters for Halicryptus, such as the presence of three different sizes of buccal papillae, scattered small trunk papillae, and a loose ring of flosculus-tubulus-complexes on the posterior trunk. For both species, we revise characters, such as the number of long introvert retractors, pharynx protractors and lateral cusps of anterior teeth, and the maximum number of scalids in a row in H. spinulosus. We propose a total of ten reliable and potential diagnostic characters distinguishing the two species and revise the terminology of Halicryptus-specific characters due to inconsistency in the literature. In addition, we discuss the effect of body size on selected morphological traits.

DESCRIPTIONS AND PHYLOGENETIC AFFINITIES OF TWO NEW SPECIES OF RHABDIAS STILES AND HASSALL, 1905 (NEMATODA: RHABDIASIDAE) FROM NORTH AMERICAN FROGS: ARE WE STILL ONLY SCRATCHING THE SURFACE?

Two new species of lung-dwelling nematodes are described from North American frogs: Rhabdias aurorae n. sp. from Rana aurora and Rhabdias conni n. sp. from Rana clamitans and Rana catesbeiana from Arkansas; the latter species was also found in Oklahoma and Georgia. Rhabdias aurorae n. sp. differs from other Nearctic congeners in the combination of the following characteristics: buccal capsule 22-25 μm wide, elongated tail covered with inflated cuticle, esophagus with prominent dilatation in anterior part and 6 small circumoral lips. Rhabdias conni n. sp. is morphologically closest to Rhabdias ranae Walton, 1929 and Rhabdias joaquinensisIngles, 1936; it differs from them in the shape of lateral pseudolabia, the dimensions of the body, and the egg size. Both new species were found to be significantly different from the Nearctic congeners in the nucleotide sequences of nuclear ribosomal DNA (18S-ITS-28S region), 12S, and CO1 mitochondrial genes. The 2 new species differ from other currently sequenced Nearctic congeners by 1.1-2.7% of nucleotide positions in the nuclear rDNA region, 1.3-3.4% in the 12S gene, and 3.4-9.4% in CO1 gene. Molecular phylogenetic analysis based on nuclear ribosomal DNA sequences placed both new species into the clade consisting of Nearctic and Neotropical Rhabdias spp. The position of Rh. aurorae n. sp. within the clade is uncertain because of a polytomy, but Rh. conni n. sp. is nested within the "Rh. joaquinensis complex" related to Rh. ranae and Rhabdias tarichaeKuzmin, Tkach, and Snyder, 2003. The phylogenetic analysis based on nuclear ribosomal DNA sequences has revealed 3 evolutionary host-switching events from anuran to caudatan hosts among Rhabdias spp. that occurred in the Nearctic and Palearctic. The molecular phylogeny also suggests that Rhabdias may have originally evolved in what is now Africa.

How dispersal rates depend on the prey capture strategy: A case study of Georgia's spiders.

Large-scale barcoding projects help to aggregate information on genetic variability of multiple species throughout their ranges. Comparing DNA sequences of both non-conspecific and conspecific individuals from distant parts of their ranges helps to compare level of genetic isolation-by-distance patterns in different species and adaptive types. We compared mitochondrial CO1 gene sequences of 223 spiders from Georgia (Caucasus), representing 124 species and eight families, with 3097 homological sequences from spiders mostly from Europe, but also from other parts of the World. In most families, a significant isolation-by distance pattern was observed on family level. On species level, a significant isolation-by-distance was observed in 40 species, although this low proportion is most likely related to a lack of data. Simultaneously, remarkable differences in spatial structure were shown for different species. Although the majority of the studied species have a broad western Palearctic range, web-building spiders from families Araneidae, Theridiidae, and Linyphiidae are less isolated spatially than flower spiders (Thomisidae), jumping spiders (Salticidae), wolf spiders (Lycosidae), sac spiders (Clubionidae), and ground spiders (Gnaphosidae). This pattern is related with more common ballooning in web building than in actively hunting spiders, which commonly remain isolated since preglacial time. Ground spiders build the most isolated populations in the Caucasus.

A new shallow water species of the palaemonid shrimp genus Palaemon Weber, 1795 (Decapoda: Caridea) from Japan

During a survey of the shallow water decapod fauna in the Miura Peninsula, Kanagawa Prefecture, central Japan, four specimens of a new palaemonid shrimp, Palaemon parvibrachium n. sp., were collected from sea grass beds of Nanozostera japonica (Ascherson & Graebner) Tomlinson & Posluszny, 2001. The new species appears morphologically similar to P. serrifer (Stimpson, 1860), one of the most common representatives of Palaemon Weber, 1795 in Japanese waters, but the short carpus of the second pereopod and the different live colouration readily differentiate the new species from the latter. A DNA barcode (a partial fragment of the mitochondrial CO1 gene), as well as a partial fragment of the mitochondrial 16S rRNA gene, are provided to genetically characterize the new species.

First record of Arionvulgaris Moquin-Tandon, 1855 (Arionidae) from Armenia.

Arionvulgaris Moquin-Tandon, 1855 is amongst the fastest-spreading terrestrial slugs Europe-wide. In recent years, it has been recorded in Canada, Mexico and continues to expand eastwards into Eurasia. Renowned for its high invasiveness, combatting its swift spread creates significant challenges in organising effective preventative measures. This study presents the first record of Arionvulgaris from Armenia, which is the second record of this species' invasion of the Caucasus. In 2022, a substantial population of A.vulgaris was observed close to the City of Stepanavan, which is also the first record in Armenia of the family Arionidae. How the species was introduced to Armenia remains unknown. Identification of Arionvulgaris was conducted, based on external and genital morphology and mitochondrial CO1 (cytochrome c oxidase subunit 1) gene sequencing, revealing notable similarities with Central European clades. Our results confirm the introduction and distribution of A.vulgaris to Armenia. Invasion of such species into Armenia will require additional monitoring and would be aided by further research on Armenia's mollusc fauna in the future.

Morphogenetic identification of a new record Deudorix livia (Lepidoptera: Lycaenidae) in Assiut Governorate of Northern Upper Egypt

Deudorix livia (Klug, 1834) (Lepidoptera: Lycaenidae) is one of the most serious lepidopteran insect pests attacking pomegranate fruit around the world, including Egypt (Assiut Governorate, Upper Egypt). To create an effective program (IPM) to control such harmful pests, accurate identification of the pest morphology and genetic structure is essential. Studies on the morphogenetics of this pest are scarce. So, the goal of this research is to identify it both morphologically and genetically. Pomegranate butterfly immature stages were collected from infested pomegranate fruits and reared in the laboratory until the adult's emergence. By using light and scanning electron microscopy, some morphological structures of males and females were studied. DNA was extracted from the legs of a pomegranate butterfly adult. Also, PCR was conducted by using the mitochondrial CO1 gene for sequencing and phylogenetic tests. The results show that the body scales are a mixture of dark and light gray on the dorsal side and white on the ventral side in both sexes. The average male body length (BL) was 11.674 ± 0.299 mm and was 11.458 ± 1.001 mm for the females. The wing venation is similar in both sexes. For the first time, a partial sequence of the mitochondrial CO1 gene in D. livia was deposited in GenBank (MW463927).

Biological observations of Salmostoma novacula fishery of a protected reservoir in India

Feeding and breeding biology of a prominent indigenous fishery of Peechi Reservoir(protected reservoir) was assessed using 300 specimens in this study. Catch compositionstudies identified Salmostoma sp. as the major species contributing to the reservoir fishery.With the help of mitochondrial CO1 gene, the species was identified as Salmostomanovacula. The feeding biology of the fishes was studied using index of preponderance(IOP), gastro-somatic index (GaSI) and relative gut length (RGL). IOP of S. novacula revealedthat zooplankton dominated the gut of the species to the tune of nearly 70.82%. The meanRGL and GaSI of S. novacula was estimated at 1.42 (1.42±0.25) and 4.22 respectively. Theindices used for reproductive study were size at first maturity, sex ratio, gonado-somaticindices and fecundity. The size at first maturity for S. novacula was found to be 13.0 cm. Thesex ratio and relative fecundity were estimated at 1.2:1.0 and 8500-8833 nos. per gram bodyweight of fish. The study indicated that the fishes mature during March to August and exhibitspawning activity in September. The paper emphasises a need for enforcing minimum legalsize and restricted monsoon fishing for sustained fisheries in this reservoir. Keywords:CO1 gene, Feeding biology, Fisheries management,Reproductive biology, Salmostoma novacula

Establishment and identification of a skin cell line from Chinese tongue sole (Cynoglossus semilaevis) and analysis of the changes in its transcriptome upon LPS stimulation

The Chinese tongue sole (Cynoglossus semilaevis) holds significant economic importance within the fishing industry along the eastern coasts of China. In recent years, the frequent outbreaks of bacterial diseases have become a common concern as the aquaculture scale expands. The majority of the diseased fish exhibit symptoms such as skin congestion, damage and skin ulceration. As the skin serves as the first line of defense against bacterial infections, establishing a skin cell line for immunological research on Chinese tongue sole's response to bacterial infection is of utmost importance. In this study, a cell line named CSS (derived from the skin of the Chinese tongue sole) was successfully established. The cells have demonstrated stability during passages and exhibit a multipolar fibroblast-like morphology. They were cultured in L-15 medium with 20% serum and have been successfully passed through 60 passages over a period of 20 months. The identification of the mitochondrial CO1 gene confirmed that the cell originated from Chinese tongue sole. The karyotype detection revealed that the cell had a chromosome number of 2n = 42. After being stored in liquid nitrogen for 15 months, the cells can maintain more than 75% viability upon recovery. After transfecting with cy3-labeled scramble siRNA and pEGFP-N3 plasmid, clear fluorescence was observed in the transfected cells. We observed that lipopolysaccharide (LPS) from Escherichia coli significantly upregulate the gene expression of various immune-related pathways at 2 h in the CSS cell line. Additionally, the differentially expressed genes showed a higher enrichment in immune-related pathways at 2 and 6 h after stimulation compared to the 24 h point. Moreover, we identified 347 genes that exhibited a gradual increase in expression during the 0–24 h stimulation period. These genes were primarily enriched in pathways related to Autophagy, GABAergic synapse, Apelin signaling and Ferroptosis. In general, the CSS cell line established in this study exhibits stable growth and can serve as a valuable tool for in vitro studies of immunology and other basic biologies of Chinese tongue sole.

Discovery of a new cryptic Achalinus Peters, 1869 (Serpentes, Xenodermidae) species from Hunan Province, China.

A new species, Achalinusshenisp. nov., from central Hunan Province is described, based on the results of molecular systematics and morphological characters according to five specimens. Our molecular phylogeny inferred from the mitochondrial CO1 gene fragment revealed that this new species is most closely related to A.yunkaiensis, but a considerable amount of genetic divergence exists between them (p-distance ranging from 5.8% to 6.4%) and much distinct genetic divergence exists compared with other known Achalinus species (p-distance ranging from 10.4% to 15.8%), supporting its validity. Morphologically, it can be distinguished from its congeners by: (1) dorsal scales strongly keeled, 23 rows throughout the body, the outmost row smooth and significantly enlarged; (2) tail relatively short, TaL/TL 0.183 ~ 0.224; (3) the suture between internasals subequal to the suture between prefrontals; (4) loreal one, subrectangular, LorH/LorL 0.53 ~ 0.57; (5) ventrals 161-170, anal entire, subcaudals 55-61, not paired; (6) the length of supraocular equal to or longer than the length of upper anterior temporal; and (7) vertebral line inconspicuous and subcaudal streak absent. Currently, 27 species of Achalinus are known in the world, amongst which 20 species are distributed in China. Moreover, a key to species of the genus Achalinus is provided in this study.

Molecular characterization of Amblyomma geoemydae using CO1 mitochondrial gene to validate phenotypic taxonomical evaluation.

Animal ectoparasites are linked to the spread of serious medical and veterinary important pathogens. Our research intends to close the knowledge gap concerning the numerous ectoparasites that inhabit animals in Wayanad. Ectoparasites in animals brought to the veterinary dispensaries in Wayanad were retrieved and identified morphologically and molecularly. Using a high-quality stereomicroscope, the taxonomic features of the four following species were examined and identified: Haemaphysalis bispinosa, Rhipicephalus annulatus, R. microplus, and Amblyomma geoemydae. The important disease vector A. geoemydae was reported for the first time in Kerala. The important phenotypic characters of the highlighted species A. geoemydae are the edge of the basis capituli is circular without cornua, and the hypostomal dental formula is 2/2. The taxonomically identified four species were subjected to CO1 gene sequence analysis. The evolutionary relationship was inspected through the neighbour-joining method, and the phylogenetic tree was built through the Maximum Likelihood method. The present study has also estimated the diversity index of R. microplus, R. annulatus, H. bispinosa, and A. geoemydae. Among them, R. microplus 0.36638 have reported with the maximum diversity index score. The significance of the study is the presence of Lyme disease vector A. geoemydae, in the Wayanad District of Kerala, and it is the first report of the species from where an outbreak of Lyme disease occurred in 2013.

Molecular Identification of Eimeria tenella in Migratory Birds, Quails, and Coturnix japonica in Balochistan, Pakistan

Introduction: Coccidiosis is a global health issue in the poultry industry. It causes serious economic losses and huge treatment costs to farmers. The current study was conducted to detect Eimeria tenella in migratory Japanese quail (Coturnix japonica) in Balochistan. Methods: In this study, a total of 300 quail fecal samples were used. Quails from Zhob, Sibi, and Quetta districts were captured using nets in September 2017 and 2018. Oocysts were detected by direct microscopy in a saline solution (0.85%), which were further identified by morphology and polymerase chain reaction (PCR) targeting mitochondrial CO-1 gene. Results: Of 300 fecal samples, 218 (72.6%) were positive for oocysts. The length, width, and shape index of oocysts of E. tenella were 21.7±1.29 µm, 19.5±1.9 µm, and 1.27±0.12, respectively. The oocysts of E. tenella were further confirmed by PCR targeting mitochondrial CO-1 gene (723 bp). Conclusion: It can be concluded that the migratory Japanese quails may be infested with E. tenella, and these birds may play roles in the transmission of this protozoan to domestic poultry

Detecting Natural Wolbachia Infection and Supergroup Identification of Metochus uniguttatus in North India

Introduction: Insect endosymbionts have a crucial evolutionary and ecological role. Insects, particularly arthropods, have evolved to tolerate a wide range of endosymbionts that provide them with external biochemical, genetic, and reproductive capacities that improve their fitness. Wolbachia is a widely prevalent bacterial endosymbiont that is gaining popularity in insect research due to its utility in pest and vector management. Although India has a diverse insect population, little research has been undertaken on insect-microbe interactions. Therefore, This study aimed to ascertain the spread of Wolbachia in a randomly sampled set of insects, identify any novel Wolbachia infections, and determine the Wolbachia infection’s supergroup. Materials and methods: Field capture of insects was carried out manually with netting and gloves, and the insects were immediately stored in absolute ethanol to immobilize them. Phenol-chloroform-isoamyl alcohol was the method used to extract the insect DNA. Insect species identification was carried out via the CO1 mitochondrial gene using PCR amplification. PCR was utilized to identify the presence of Wolbachia, and 16S Wspec DNA was amplified to confirm its presence. The Sanger method was used to sequence the amplified CO1 and the positive samples for Wspec. Using NCBI blast, the sequences of the infected insects were compared with the database sequences. The obtained FASTAs were then aligned using Sequencher 5.4.6, and the chromatograms were examined to ensure contig quality and similarity. Results: Among the 21 insects screened, one was found weakly positive (Playpleura octoguttata) and two were strongly positive (Metochus uniguttatus and Velarifictorus micado) with Wolbachia, which represented an infection rate of 14.29%. Although the individual infection rate in this limited sample size falls at the lower end compared to extensive surveys reporting rates between 20% and 76%. This study indicated the dissemination of Wolbachia in randomly screened insects. Moreover, this is one of the first records of Metochus uniguttatus being infected with Wolbachia in North India. Conclusion: This study represents an initial exploration of insects not previously considered hosts of the Wolbachia endosymbiont. The results could be useful for future studies on insect biocontrol and pest management.

Molecular phylogeny of anchovy (Clupeiformes: Clupeidae) from southern waters of Lombok using mitochondrial DNA CO1 gene sequences

Abstract. Mahrus H, Idrus AA, Zulkifli L. 2022. Molecular phylogeny of anchovy (Clupeiformes: Clupeidae) from southern waters of Lombok using mitochondrial DNA CO1 gene sequences. Biodiversitas 23: 2433-2443. This study aimed to identify anchovy samples genetically and evaluate their phylogenetic relationship to anchovies using the CO1 genetics markers. Fragment amplification of COI gene anchovy used a pair of COI commercially available primer with a length amplicon of about 693 base pairs (bp), coding for 231 amino acids successfully. The reconstruction of the phylogenetic tree with the neighbor-joining (NJ) method using Kimura 2 Parameters (K2P) by employing a bootstrap of 1000 replications. The genetic distance analysis between 19 fishes species in different families and 13 species in the genera Spartelloides acceded from NCBI indicated the closest distance between anchovy samples from the southern waters of Lombok and Spratelloides delicatulus from Australia is 0.02. The comparisons results of homology with the NCBI and the BOLD database show the anchovy sample has similarities to the CO1 sequences of S. delicatulus with a similar of 99%. The results of the phylogenetic tree analysis showed that the anchovy samples from the southern waters of Lombok were in the same clade as S. delicatulus from Australia. The study concluded a fish sample of anchovy from the southerly waters of Lombok was a closed related species to S. delicatulus.

Comparison between different populations of Nile Pufferfish (Tetraodon lineatus) in Lake Nasser, Aswan, Egypt using Mitochondrial CO1 gene

Comparison between different populations of Nile Pufferfish (Tetraodon lineatus) in Lake Nasser, Aswan, Egypt using Mitochondrial CO1 gene

The Phylosymbiosis Pattern Between the Fig Wasps of the Same Genus and Their Associated Microbiota.

Microbial communities can be critical for many metazoans, which can lead to the observation of phylosymbiosis with phylogenetically related species sharing similar microbial communities. Most of the previous studies on phylosymbiosis were conducted across the host families or genera. However, it is unclear whether the phylosymbiosis signal is still prevalent at lower taxonomic levels. In this study, 54 individuals from six species of the fig wasp genus Ceratosolen (Hymenoptera: Agaonidae) collected from nine natural populations and their associated microbiota were investigated. The fig wasp species were morphologically identified and further determined by mitochondrial CO1 gene fragments and nuclear ITS2 sequences, and the V4 region of 16S rRNA gene was sequenced to analyze the bacterial communities. The results suggest a significant positive correlation between host genetic characteristics and microbial diversity characteristics, indicating the phylosymbiosis signal between the phylogeny of insect hosts and the associated microbiota in the lower classification level within a genus. Moreover, we found that the endosymbiotic Wolbachia carried by fig wasps led to a decrease in bacterial diversity of host-associated microbial communities. This study contributes to our understanding of the role of host phylogeny, as well as the role of endosymbionts in shaping the host-associated microbial community.

Toxorhynchites (Lynchiella) caatingensis sp. nov. (Diptera: Culicidae) from the semi-arid region of Brazil

This publication describes a new species of mosquito of the genus Toxorhynchites Theobald, 1901, subgenus Lynchiella Lahille, 1904. The species was found during an exploratory survey of the Culicidae in the Caatinga biome, which is unique to Brazil and characterized by a semi-arid climate. Because of the specific characteristics of the biome, it has potential for endemism of species that have adapted to its restrictive conditions, particularly those imposed by severe drought. The new species, Toxorhynchites (Lynchiella) caatingensis, is a phytotelmic species that inhabits bromeliads and has an unknown biology. It belongs to a species complex that is hereafter referred to as the Violaceus Complex, which comprises three species that are found in the same type of habitat and have similar morphology: Tx. caatingensis n. sp., Tx. mariae (Bourroul, 1904) and Tx. violaceus (Wiedemann, 1820). We describe the larva, pupa, adult female and male genitalia of specimens collected as larvae from the tank bromeliad Aechmea aquilega (Salisb.) Griseb. The main distinctive characteristics of the species are the presence of three lateral tufts on the terminal abdominal segments (one pale and the others dark); a blue midline on the abdominal sterna; in the pupa, the pentagonal shape of the paddle and the length of seta 6-V. PCR reactions were carried out for the mitochondrial CO1 gene fragment, which placed the new species in the subgenus Lynchiella. No match was found with any species recorded in GenBank. The subgenus now includes 17 species.

Identification of a New Species of the Medicinal Leeches in India using DNA Barcoding Technique - a Breakthrough

Leech therapy has always been an important treatment modality in Ayurveda. Medicinal leeches are known for their extensive therapeutic uses. Identification of leech species is an important research area to understand the mechanism of therapeutic gains and exploring more probable benefits. Researchers have done a swell job in identifying various species of leeches in different parts of Asia including India. For therapeutic purpose however, the clinicians in India have not bothered much about the exact identification of leech species being used at different centres. There is dearth of research papers in this aspect. Thus a study was planned to identify the species of leeches being used at our centre.
 Materials and methods: DNA Barcoding technique was used where mitochondrial CO1 gene was amplified using LCO-HCO primers.
 Results: DNA sequencing of Leech sample closely resembled to Hirudinaria Bpling species, which is a breakthrough in existing knowledge of medicinal leeches in India, as this species was recently reported to be found in Thailand in 2012 for the first time. No previous documentation of its existence is available in our country.
 Conclusion: Further studies on large scale are required to explore their existence, morphological features and salivary contents in regard to their medicinal value. This will help in exploring any additional benefits to the existing knowledge of therapeutic uses of medicinal leeches. This study will pave the path to new avenues in therapeutic utility of leeches, as the newer species might have additional bioactive chemicals making them useful in wider variety of disorders.

Genetic diversity of Syphacia Seurat, 1916 (Nematoda: Oxyuridae) across the hybrid zone of their rodent hosts in Russia.

The genetic diversity of Syphacia nematodes (intestinal parasites of rodents) was studied in the hybrid zone of two sister species of common voles, Microtus arvalis and Microtus obscurus, in the Oka River valley, east of Moscow. Syphacia nematodes of other rodent species (Microtus rossiaemeridionalis, Alexandromys oeconomus, Sylvaemus uralensis, and Apodemus agrarius) that inhabit the area were also studied. Phylogenetic trees for the studied nematodes were inferred from the analysis of nuclear ITS1+5.8S+ITS2, LSU rDNA, and mitochondrial CO1 gene partial sequences. Syphacia nematodes of the studied area form three well-defined clades in the phylogenetic tree of this genus. Morphological analysis revealed similarities between the obtained sequences with those of known Syphacia species from the GenBank database, which enabled identifying these three clades up to the species level: S. montana, S. agraria, and S. frederici. Russian haplotypes of Syphacia are different from West European and East Asian haplotypes with pronounced genetic distances. A high level of specificity was reported for two of these three species (S. frederici, only in Sylvaemus uralensis; S. agraria, only in Apodemus agrarius). S. montana was found in different species of voles. Remarkably, S. montana specimens from M. arvalis and M. obscurus were genetically uniform, while S. montana, specimens from hybrids between these two species formed a separate clade distant from those originating from non-hybridised hosts.

Генотипирование черноморских трематод семейства Opecoelidae по митохондриальным маркерам

Opecoelidae Ozaki, 1925 (Trematoda: Opecoeloidea) — ведущее по числу видов и родов семейство трематод в Чёрном море. Мариты наиболее распространённых видов черноморских опецелидных трематод подробно описаны морфологически, однако сведения о структуре их геномов отрывочны, а данные о митохондриальных геномах отсутствуют полностью. Цель исследования — получить первые сведения о строении участков митохондриального генома представителей наиболее распространённых в Чёрном море в современный период родов трематод семейства Opecoelidae для последующего уточнения их таксономического статуса. Филогенетические отношения внутри анализируемой части этого семейства реконструированы на основе данных, полученных нами, и соответствующих данных из GenBank с помощью алгоритма Maximum Likelihood и модели нуклеотидных замен HKY. Для укоренения филогенетического дерева использованы соответствующие последовательности Brachycladium goliath (Brachycladioidea: Brachycladiidae). Поскольку последовательности CO1 — стандартного и наиболее популярного митохондриального маркера — для исследуемых родов опецелид до сих пор не были известны, нами на основе известных соответствующих последовательностей Xiphidiata разработаны праймеры для амплификации фрагмента CO1, чтобы впервые провести соответствующий филогенетический анализ. Впервые определены и депонированы в GenBank нуклеотидные последовательности фрагментов митохондриальных генов CO1 и 16S черноморских трематод Cainocreadium flesi Korniychuk & Gaevskaya, 2000, Gaevskajatrema perezi (Mathias, 1926) Gibson & Bray, 1982 и Helicometra fasciata (Rudolphi, 1819) Odhner, 1902 от разных видов дефинитивных хозяев — рыб. У C. flesi не выявлено специфичных к окончательным хозяевам — рыбам линий по структуре фрагмента митохондриального гена CO1, однако отмечено высокое CO1-нуклеотидное разнообразие. У марит черноморских H. fasciata определена приуроченная к зеленушкам-руленам Symphodus tinca CO1-гаплогруппа, статус которой требует дальнейшего выяснения; необходимы экологические и генетические исследования предполагаемого видового комплекса H. fasciata из разных акваторий. При анализе последовательностей фрагмента митохондриального гена 16S рРНК гостальных генетических линий у H. fasciata выделить не удалось. У черноморских G. perezi не обнаружено значительных различий по фрагменту 16S между трематодами из окончательных хозяев разных видов, однако внутривидовое 16S-нуклеотидное разнообразие оказалось высоким.

Locomotor responses to salt stress in native and invasive mud-tidal gastropod populations (Batillaria).

Plasticity in salt tolerance can be crucial for successful biological invasions of novel habitats by marine gastropods. The intertidal snail Batillaria attramentaria, which is native to East Asia but invaded the western shores of North America from Japan 80 years ago, provides an opportunity to examine how environmental salinity may shape behavioral and morphological traits. In this study, we compared the movement distance of four B. attramentaria populations from native (Korea and Japan) and introduced (United States) habitats under various salinity levels (13, 23, 33, and 43 PSU) during 30 days of exposure in the lab. We sequenced a partial mitochondrial CO1 gene to infer phylogenetic relationships among populations and confirmed two divergent mitochondrial lineages constituting our sample sets. Using a statistical model‐selection approach, we investigated the effects of geographic distribution and genetic composition on locomotor performance in response to salt stress. Snails exposed to acute low salinity (13 PSU) reduced their locomotion and were unable to perform at their normal level (the moving pace of snails exposed to 33 PSU). We did not detect any meaningful differences in locomotor response to salt stress between the two genetic lineages or between the native snails (Japan vs. Korea populations), but we found significant locomotor differences between the native and introduced groups (Japan or Korea vs. the United States). We suggest that the greater magnitude of tidal salinity fluctuation at the US location may have influenced locomotor responses to salt stress in introduced snails.