Genetic diversity of Ichthyophthirius multifiliis (Fouquet, 1876) infecting farmed rainbow trout (Oncorhynchus mykiss Walbaum, 1792) in Turkey.

We assessed genetic diversities among Ichthyophthirius multifiliis (Ich) field isolates collected from farmed rainbow trout (Oncorhynchus mykiss) in Turkey. The overall prevalence of Ich was 35.3% (634/1798). Five novel Ich genotypes (ImulTR1 and ImulTR3-ImulTR6) were described based on mitochondrial cox-1 and nad1_b genes. The remaining genotype ImulTR2 was identical to the previously reported NY3 (or Ark9 and TW7) genotype from the United States and South Asia. Phylogenetic analysis indicated Turkish Ich isolates separated genetically into at least four distinct groups. Our study presents the first data on the genotypes of Ich in Turkey. We also provide evidence for the wide distribution of the NY3 genotype (or Ark9 and TW7) from the United States and South Asia to Turkey. Genetic diversities within the mitochondrial genes provided adequate resolution for describing novel genotypes and identifying the known genotype within Turkish Ich isolates. Description of the Ich genotypes allows for tracking of pathogen genotypes worldwide. Thus, we can better understand the connections between Ich outbreaks in the fisheries aquaculture.

Morphology of the tongue dorsal surface of turbot (Scophthalmus maximus).

This study aimed to analyze the morphology of the tongue, which varies among fish species and has not been studied in turbot (Scophthalmus maximus), using macro-anatomical, light and scanning electron microscopy (SEM). As research materials, the tongues of eight adult turbot, which were used for consumption, were examined. The roughly triangular-shaped tongue of the turbot consisted of three parts: apex, body, and root. The thickness of the tongue continued to increase from the apex to the root. Although papillae were not observed in the macroscopic examination of the tongue, microscopic examination revealed the presence of cone-like shaped papillae on the submucosa. The tongue was composed of mucosa, submucosa, and hyaline cartilage. By SEM the presence of the taste buds (Types I and III), taste pores and papillae on the dorsal surface were demonstrated. Taste buds are the first descriptions in S. maximus. Therefore our results could add new data to the fish tongue anatomy. HIGHLIGHTS: Morphological and morphometric data of the turbot (Scophthalmus maximus) tongue were obtained in this study and compared with other species. In addition, the dorsal surface of the turbot tongue was described for the first time using SEM.

Novel and known myxobolids (Cnidaria, Myxozoa) infecting Chondrostoma angorense (Cypriniformes: Leuciscidae) in Turkey.

Turkey has more than 200 endemic freshwater fish species, one of which is the Ankara nase, Chondrostoma angorense Elvira, 1987 (Cypriniformes: Leuciscidae), a food fish in northern Turkey. Like most endemic fish species in Turkey, its myxosporean parasite fauna (Cnidaria: Myxosporea) are not yet described. We surveyed twenty C. angorense from Lâdik Lake in northern Turkey, and identified two myxosporean parasites from gills of these fish: Myxobolus arrabonensis Cech, Borzák, Molnár, Székely, 2015, and a co-infection of a novel species, Myxobolus polati sp. nov. We characterized both infections based on myxospore morphology, morphometry, tissue tropism, small subunit ribosomal DNA sequence and phylogenetic analysis. Plasmodia of both species were observed in gills, but had distinct tropism: M. arrabonensis is an intrafilamental vascular type, and M. polati sp. nov. is an intralamellar vascular type. We identified M. arrabonensis on the basis of myxospore characters and 100% similarity to the type DNA sequence from the closely-related host C. nasus. The small subunit ribosomal DNA sequence of M. polati sp. nov. (1946 base pairs; GenBank Accession number MH392318) had a maximum similarity of 98% with any Myxobolus sp. from other Eurasian cypriniforms. Phylogenetic analysis revealed that M. polati sp. nov. is most closely related to gill-infecting Myxobolus diversicapsularis from Rutilus rutilus (L.). The present study is the first record of myxosporean species infecting C. angorense comprising a novel species, M. polati sp. nov. and a known species M. arrabonensis.

Four novel Myxobolus species (Cnidaria: Myxozoa) infecting Anatolian khramulya Capoeta tinca (Cyprinidae) in northern Turkey.

We identified Myxobolus anatolicus Pekmezci, Yardimci, Yilmaz & Polat, 2014 and 4 novel Myxobolus species from the Anatolian khramulya Capoeta tinca (Cyprinidae) in northern Turkey based on morphology, histology, and phylogenetic analysis. M. karaeri sp. nov. plasmodia were observed in the skin doublets between fin rays, the surfaces of the operculum, the gill arch membrane, and in the skin of the fin base. M. samsunensis sp. nov. plasmodia were observed in epithelial tissue inside and on the surface and midline of the gill filaments. M. cakmaki sp. nov. presented as a typical vascular species, which develops in large plasmodia at the end of the gill filaments. The chondrophilic M. ekingeni sp. nov. was detected by histology inside the cartilaginous gill arch and the cartilaginous gill rays of the filaments. Phylogenetic analysis of small subunit ribosomal DNA sequences revealed that M. karaeri sp. nov. and M. samsunensis sp. nov. were clustered with Myxobolus species that infect gills, scales, and fins of cyprinids. M. cakmaki sp. nov. grouped with Myxobolus species that exclusively infect the gills of cyprinids. No molecular data were available for M. ekingeni sp. nov.

The fine structure of the turbot eye (Scophtalmus maximus): A macro-anatomical, light and scanning electron microscopical study.

In fish species, the morphological structure of the eye varies depending on environmental conditions. Morphometric data about the sensory organs of fish is lacking. Therefore, this study aims to describe the morphological structure of the turbot eye using gross, light and scanning electron microscope examinations. The turbot eyeball was found to comprise three layers: the tunica fibrosa bulbi (cornea, sclera), the tunica vasculosa bulbi (choroidea, iris) and the tunica nervea bulbi (retina). The thickness of the centre of the cornea measured approximately 153.14 µm, and the peripheral thickness measured 410.81 µm. The sclera consisted of a two-part cartilage structure that was connected with elastic fibres. The choroideal rete was found in the tunica vasculosa bulbi, and its thickness measured 1.6 ± 0.1 mm. Moreover, no pigment was found in the choroidea. The lens was determined to be a very hard and transparent structure extending towards the cornea. In addition, we detected five ligaments in the equatorial plane of the eye, in which the tendon of the retractor lentis muscle attaches to the lens. Also, there were six extraocular muscles in the turbot. This study is the first to present detailed descriptions of morphological structures and morphometric data for all the layers of the turbot eye. Since the anatomical structure of the eye in fish is variable, it is thought that the data on the turbot eye will contribute to the anatomy literature.

On the occurrence and molecular identification of Contracaecum larvae (Nematoda: Anisakidae) in Mugil cephalus from Turkish waters.

Anisakis and Contracaecum species are fish borne zoonotic nematodes. In our previous studies, other larval anisakid and raphidascarid nematodes, Anisakis and Hysterothylacium species, were genetically identified in marine fish from Turkish waters. However, there is no information on molecular identification of larval Contracaecum species in marine fish from Turkey. Therefore, the aim of this study was only to investigate the presence and molecular identification of Contracaecum species in commonly commercialized marine fish from Turkish waters. A total of 475 marine fish, which belong to 21 different species, were sampled from the Aegean (FAO 37.3.1), Mediterranean (FAO 37.3.2), and Black Sea (FAO 37.4.2). The prevalence of Contracaecum L3 larvae in the Aegean Sea was identified as 10% in Mugil cephalus. All Contracaecum L3 larvae were molecularly characterized with RFLP targeting the ITS region and rrnS gene. Moreover, all larvae were analyzed by sequencing of ITS region, rrnS and cox2 gene. All Contracaecum larvae were identified as C. overstreeti based on the cox2 sequence analysis. This is the first report of C. overstreeti larvae in M. cephalus as paratenic and intermediate hosts. Furthermore, the analysis reveals novel information on ITS region. Additionally, the rrnS gene of C. overstreeti was also achieved and deposited in Genbank for the first time. The PCR-RFLP patterns of the ITS region and rrnS gene from C. overstreeti were presented in the present study. Consequently, the presence of C. overstreeti larvae in M. cephalus from the Aegean Sea may also potentially capable of inducing allergic sensitization in humans.

Ichthyobodo spp. Infection in Meagre (Argyrosomus regius) from Turkey: Parasitological and Pathological Findings.

OBJECTIVE: The aim of this study is to describe the first report of Ichthyobodo spp. infection in meagre (Argyrosomus regius) fry in a marine aquaculture facility in Turkey. METHODS: The material of the study was composed of 30 meagre A. regius in 2-3 g weight taken from the fry adaptation unit of a fish farm in the Aegean Sea. In this study, parasitological and pathological examinations were performed on the meagre. Ichthyobodo spp. was determined on the body surfaces and gills. RESULTS: Pathological examination revealed grayish mucous and erosions between the pin head and lentin over the skin of the examined specimens. Microscopic examinations revealed significant spongiosis, vacuolar degeneration, and hyperplasia in epidermal malpighian cells and hyperplasia in goblet cells. CONCLUSION: In the present study, Ichthyobodo spp. infection was for the first time determined in an alternative cultured meagre in Turkey.

Supplementary studies and the first molecular data on Myxobolus scardinii Reuss, 1906 (Myxozoa: Myxosporea) infecting the gill filaments of rudd, Scardinius erythrophthalmus (L.).

Within the present study, we offer new information on the morphology, histopathology, and 18S ribosomal DNA (rDNA) sequence of Myxobolus scardinii to supplement and revise the original description of Reuss (Bull Acad Imp Sci St-Pétersbourg, V Serie, XXV, No. 3: 199-205, 1906). M. scardinii was found infecting the gills of 6 of 125 specimens (4.8%) of Scardinius erythrophthalmus from northern Turkey. Large mature plasmodia, whitish, spherical, or ellipsoidal, measuring 0.9-1.0 mm in diameter, macroscopically occurred in the gills. Histopathological examination indicated that development of the cyst-like plasmodia was intrafilamental-vascular type. Mature spores are oval or shortly ellipsoidal. The spores are 12.1 ± 0.2 (11.5-12.6) µm long, 8.9 ± 0.3 (8.4-9.2) µm wide, and 6.1 ± 0.3 (5.9-6.2) µm thick. The two polar capsules are equal in size, 4.8 ± 0.2 (4.7-5.1) µm long and 2.8 ± 0.2 (2.7-3.1) µm wide, and are long pyriform in shape. A well-developed intercapsular appendix was found in the fresh spores. In this study, a specific gill myxosporean of S. erythrophthalmus, M. scardinii the identity of which was confirmed by careful morphological and histopathological examination, was sequenced with its 18S rDNA sequence for the first time and submitted to Genbank database (accession number KJ562362). Phylogenetic analysis of the 18S rDNA gene revealed that M. scardinii had the closest similarity to M. muelleri and M. bramae. This is the first molecular data for the validity of M. scardinii in S. erythrophthalmus. This new valid genetic data (KJ562362) has been used to establish phylogenetic relationships with other similar gills Myxobolus species from Eurasia.

Myxobolus anatolicus sp. nov. (Myxozoa) infecting the gill of Anatolian khramulya Capoeta tinca (Cyprinidae) in Turkey.

This work is part of an ongoing investigation into the characteristics of myxozoan parasites of freshwater fish in Turkey and was carried out using morphology, histopathology and molecular analysis. A new species of the genus Myxobolus (M. anatolicus sp. nov.) was found infecting the gills of 3 of 34 specimens (8.8%) of Anatolian khramulya Capoeta tinca from the Samsun Province, Northern Turkey. Both morphology and 18S rDNA sequence data revealed that M. anatolicus sp. nov. was distinct from other Myxobolus species found in the gills of cyprinid fishes. The small, white and round-shaped plasmodia, measuring 0.2 to 1.4 mm in diameter, were observed macroscopically in the gills. Histological analysis revealed that the cyst-like plasmodia have an intralamellar-vascular type development. Mature spores of M. anatolicus sp. nov. were oval in both frontal and sutural views, and tapered at the anterior poles. The spores were 10.1 ± 0.41 (9.4 to 10.7) µm long, 6.9 ± 0.28 (6.6 to 7.2) µm wide, and 4.5 ± 0.36 (4.4 to 4.6) µm thick. The 2 polar capsules were pyriform, equal in size, 4.6 ± 0.45 (4.4 to 4.8) µm long and 2.1 ± 0.12 (2 to 2.3) µm wide. Polar filaments within the polar capsules were coiled with 5 or 6 turns. Phylogenetic analysis placed M. anatolicus sp. nov. in a clade of gill-infecting myxobolids. This is the first record of a Myxobolus species infecting Anatolian khramulya Capoeta tinca, and the first record of this species from Eurasia.

Molecular identification of Anisakis species (Nematoda: Anisakidae) from marine fishes collected in Turkish waters.

Anisakid nematodes are important etiological agents for zoonotic human anisakiasis (or anisakidosis). These parasites in the Turkish waters still remain unexplored. This study aims the molecular identification of Anisakis species in Turkey's coast from Black, Aegean and Mediterranean Sea and specifically to screen for zoonotic species in commonly commercialized a total of 1145 fish belonging to 31 different species using both polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) and sequencing of the ribosomal internal transcribed spacer (ITS) regions and the mitochondrial cytochrome C oxidase subunit II (cox2) gene. A total of 776 Anisakis type I larvae were isolated in 56/1145 (4.8%) fish of 7 species from Turkish waters. The combining all of our results, e.g., morphology, PCR-RFLP, ITS region, and the cox2 gene, conclusively supported the identification of 3 Anisakis spp. taken from marine fish hosts, namely Anisakis pegreffii, Anisakis typica and Anisakis simplex sensu stricto (s.str.)/A. pegreffii hybrid genotype. No Anisakis larvae were isolated from the Black Sea whereas A. pegreffii, A. typica and A. simplex s.str./A. pegreffii hybrid genotype was found in the Aegean Sea and A. pegreffii was only isolated from the Mediterranean Sea. This study represents the first identification of A. typica and A. simplex s.str./A. pegreffii hybrid genotypes from Turkish waters. Moreover, in the present study first record of the presence of A. pegreffii is also reported from Turkish coasts of Aegean and Mediterranean Sea. No zoonotic Anisakis species were found in commonly commercialized 1025 fish belonging to 16 different species from the Black Sea, thus Turkish populations who consume captured fish from the Black Sea may have a less risk of human anisakiasis or allergies. However, the prevalence of larvae were 47.1% and 46% and recognized zoonotic A. pegreffii were identified from the Aegean and Mediterranean Sea coast, suggesting a high threat of anisakiasis or allergies for Turkish populations who consume fish originating in these regions.

Molecular characterization of Hysterothylacium fabri (Nematoda: Anisakidae) from Zeus faber (Pisces: Zeidae) caught off the Mediterranean coasts of Turkey based on nuclear ribosomal and mitochondrial DNA sequences.

In the present study, Hysterothylacium fabri was found in the coasts of the Mediterranean Sea, Turkey and characterized by sequencing of nuclear (internal transcribed spacer, ITS) and mitochondrial (cytochrome c oxidase subunit 2, cox2) markers. Pairwise comparison between the entire ITS fragment including ITS-1, 5.8S, ITS-2 sequences of the H. fabri isolates from the Mediterranean Sea (Turkey, KC852206) and other H. fabri isolates from the South China Sea (JQ520158), the South Korea waters (JX974558) showed differences ranged from 0.1 and 1.1%. With the present study, H. fabri from the Mediterranean Sea was characterized for the first time by sequencing of the cox2 gene.