Small Subunit 18S rRNA Research Articles

IDENTIFICATION AND PREVALENCE OF CRYPTOSPORIDIUM SPECIES FROM SELECTED CAPTIVE BIRDS IN DISTRICT KASUR

The most prevalent protozoan that can infect a variety of animals, including birds and mammals, is Cryptosporidium. Certain species of Avian Cryptosporidium spp. are zoonotic and can cause fatal respiratory and digestive disorders in birds. Because they are in close proximity to humans, captive birds have the potential to serve as reservoirs. The current study reveals the molecular characteristics and prevalence of Cryptosporidium spp. from selected captive birds kept in district kasur. Fifty fresh fecal samples from captive birds belonging to three bird orders and five species were collected. To identify Cryptosporidium species, a polymerase chain reaction (PCR) technique that targets the small subunit 18S rRNA gene was employed. The prevalence rate of Cryptosporidium in captive birds was 6%. Of the three samples, Cryptosporidium baileyi 10% (1/10), Cryptosporidium meleagridis 5.5% (1/18) and Cryptosporidium parvum 10% (1/10). The rate of occurrence Cryptosporidium spp. infecting captive birds in Kasur having zoonotic potential is probably low. These findings provide baseline information to support future research on the genetic epidemiology and management of Cryptosporidium infection in avian species in Kasur

Morphological and molecular data establishes Clinostomum dolichorchum n. sp. (Digenea: Clinostomidae) in the great blue heron Ardea herodias L. and American bullfrog Rana catesbeiana Shaw.

Clinostomum is a cosmopolitan genus of trematodes that infect piscivorous birds, freshwater molluscs, freshwater fish and amphibians. Herein, a novel species of Clinostomum is described based on morphological and molecular data from an adult in the oral cavity of the great blue heron Ardea herodias and metacercariae collected from the gills and skin of American bullfrog tadpoles Rana catesbeiana. The novel species shares similar qualitative and quantitative morphological features with a congener, Clinostomum marginatum, which has overlap in host and geographic distribution. The most notable morphological difference when compared to C. marginatum is the greater posterior testis length of the novel species. Molecular data resolved similarities with morphological comparisons to nominal species and supports the establishment of a novel species. Molecular data include partial small ribosomal subunit (18S rRNA gene), ribosomal internal transcribed spacer regions (ITS1, 5.8S rRNA gene, and ITS2), partial large ribosomal subunit (28S rRNA gene), cytochrome c oxidase subunit 1 gene (cox1), and nicotinamide adenine dinucleotide dehydrogenase subunit 1 gene (nad1) sequences. Phylogenetic analyses place the novel species in a sister clade to C. marginatum. Morphological and molecular data, combined with phylogenetic analyses support the establishment of Clinostomum dolichorchum n. sp.

Microsporidian heavy infection in a batch of salted and dried cod.

The aim of this work is the description and characterization of a severe microsporidian infection in a batch of salted and dried cod. Particularly, the case involves a batch of approximately 800 kg obtained from Gadus macrocephalus (Food and Agriculture Organization Zone 61 - Northwest Pacific Ocean), which, after rehydration and sectioning operations, underwent routine company checks before packaging. In about 20% of the samples, the presence of whitish nodules with a diameter ranging from 1 to 2 mm was observed on the surface of the fillets and in cross-section. The lesions ranged from a few units to 10 per cm2. Some samples were subjected to fresh microscopic observation with the stereomicroscope, confirming the nodular nature of the lesions, which were often confluent, alternating with empty spaces, giving the tissue a honeycombing aspect. The histological examination at low magnification allowed us to observe the heavy vacuolization of nodular lesions irregularly surrounded by a spongy-like wall. The observation at higher magnification of other sections allowed us to identify intra-myofibrillar cists containing presumptive microsporidian elements. The tissue damage derived from the technological processes and gravity of lesions did not allow a morphological characterization of presumptive protozoans. The molecular examination of the nodular lesions and the analysis of the sequence of an 897 bp fragment of the small subunit 16S rRNA revealed 100% identity with Microsporidium theragrae (GenBank accession number MT928885-89) first isolated from the skeletal muscles of Gadus chalcogrammus specimens from the Sea of Okhotsk. This finding confirms the importance of selecting suppliers and raw materials in the seafood industry, as well as the usefulness of an effective traceability system.

The Shoshone Canyon Conduit Cave: A Greater Yellowstone Ecosystem Sulfur Cave

Fve miles west of Cody, Wyoming and ~25 miles east of Yellowstone National Park lies the Shoshone Canyon Conduit Cave (Fig. 1, Suppl. material 1). Bisecting Cedar Mountain, an irrigation tunnel built by the Bureau of Reclamation (BoR), managed by the Heart Mountain Irrigation District, delivers water from the BoR Buffalo Bill Reservoir to more than 30,000 acres of irrigated lands in and around Cody. During the construction of that tunnel in the late 1940’s, a cave was discovered and the tunnel was made to travel though the cave with only light disturbance to the cave. The cave can only be accessed with permission in the non-irrigation time of year. The cave is rich in sulfides and sulfur deposits with unique speleothems. To date, we have conducted a preliminary geobiological survey of the geochemistry, microbiology and mineralogy of this sulfur cave on its speleothems, mineral deposits and waters. Sampled waters, of which there is little, were all highly acidic (pH < 2). Microbiologically, an analysis of microbial communities present in approximately 25 sample locations (Fig. 1) to answer the question of—who is there?—was conducted via small subunit ribosomal 16S rRNA gene (for Bacteria and Archaea) and 18S rRNA (for Eukarya) analyses, prepared using a polymerase chain reaction (PCR) primer-pair that allows for the even amplification of all three domains of life. All samples were relatively low in biomass and resultant community analysis indicates a variety of Bacteria and Archaea phyla are represented with a dominance of known sulfur metabolizers. Mineralogically, petrography reveals a variety of crystal growth and habit in this sulfur-dominated, calcium carbonate-driven karstic ecosystem. X-ray diffraction analysis (XRD) was used to better determine the kinds and extant of mineral morphotypes and were surprisingly variable. The Shoshone Canyon Conduit Cave is a most intriguing sulfur cave to reveal what is known of the geobiology of sulfur caves in the Rocky Mountain Region. Findings from this work will likely apply to other cave systems such as Villa Luz (Mexico) and the Frasassi system (Italy). Finally, to learn about the Cedar Mountain Caves will inform on how either or both the National Park Service (NPS) and Bureau of Land Management (BLM) may better manage them as a meaningful component of the Greater Yellowstone Ecosystem.

Integrative taxonomy and phylogenetic relationships between representatives of genera within Merliniinae (Nematoda: Merliniidae), with new data on fourteen known and one unknown species.

The application of integrative taxonomic approaches is useful to species delineation based on a combination of distinct types of characters, here morphological features and ribosomal DNA sequences. In this study, we surveyed ectoparasitic nematodes of the subfamily Merliniinae in cultivated and natural environments in Iran. Results of morphological and morphometrical studies, light and scanning electron microscopic observations, and molecular analyses allowed us the identification of fourteen known and one unknown species including representatives of the genera Amplimerlinius (five species), Geocenamus (one species), Merlinius (three species), Nagelus (two species), Paramerlinius (one species), Scutylenchus (two species), and Telomerlinius (one species). The unknown species, Scutylenchus sp., characterized by having 35-50 incisures at mid-body; lateral field with 6 longitudinal incisures; lip region slightly offset by a constriction, flattened at front end; bearing 5-7 annuli; cephalic framework not refractive; stylet robust, 18.3-27 μm long; post anal intestinal sac absent; tail elongate conical, dorsally convex, with 24 (19-28) annuli in ventral side, ending to a smooth terminus and males common; spicules 24.5-31 μm long. The phylogenetic analyses were carried out using molecular data from nuclear ribosomal DNA (rDNA) genes viz. D2-D3 expansion segments of the large ribosomal subunit (28S rRNA), partial small ribosomal subunit (18S rRNA), and internal transcribed spacer (ITS). The molecular variability of D2-D3 expansion segments of the 28S rRNA and partial 18S rRNA was low in this family in comparison to the ITS region, which could be a more helpful molecular marker in species and genus identification.

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

BackgroundThe 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.ResultsWe 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.ConclusionsLarge 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.Graphical

Direct Molecular Detection and Phylogenetic Tree Analysis of Gastrointestinal Protozoan Parasites (Giardia lamblia, Entamoeba his-tolytica, Cryptosporidium parvum) from Diarrhea Infection in Kut City of Iraq: A Short Communication

Background: The intestinal tract of human can be infected by protozoan parasites. In this short communication, the stool samples were collected from patients with diarrhea referred to Kut hospital, Iraq, and then the parasites (Giardia lamblia, Entamoeba histolytica, Cryptosporidium parvum) were considered for molecular identification.
 Methods: Stool samples were collected from 69 patients with diarrhea and then transferred to laboratory. Protozoan parasites were evaluated by Polymerase Chain Reaction (PCR) and phylogenetic tree analysis. Small subunit 18S rRNA region was amplified in the sizes of 514 bp, 409 bp, and 507 pb for G. lamblia, E. histolytica, and C. parvum, respectively.
 Results: The results of phylogenetic tree analysis showed that G. lamblia had 99% identity to G. lamblia with accession number of DQ157272.1 (and total genetic changes of 0.002%); E. histolytica also had 99% identity to E. histolytica with accession number of GQ423748.1 (total genetic changes of 0.0005%); and C. parvum had 99% identity to C. parvum with accession number of AJ539197.1 (total genetic changes of 0.05%).
 Conclusion: Gastrointestinal symptoms in the individuals with the studied protozoan parasites can be diagnosed directly by molecular detection and phylogenetic tree analysis with satisfying results. As well as, it can be utilized like a target for therapeutic intervention for these enteric protozoans.

Two independent genetic markers support separation of the myxomycete Lycogala epidendrum into numerous biological species

ABSTRACT Lycogala epidendrum is one of the most widely known myxomycete species and the first-ever discovered representative of this group. Using 687 original DNA sequences from 330 herbarium specimens from Europe, Asia, North and Central America, and Australia, we constructed the first detailed phylogenies of the genus Lycogala, based on two independently inherited genetic markers, the ribosome small subunit 18S rRNA nuclear gene (18S rDNA) and the mitochondrial cytochrome oxidase subunit I gene (COI). In both phylogenies, L. epidendrum appeared to be a polyphyletic group, represented by numerous clades. The four other recognized species of the genus (L. confusum, L. conicum, L. exiguum, and L. flavofuscum) are scattered between branches corresponding to L. epidendrum. A barcode gap analysis revealed 60 18S rDNA phylogroups of L. epidendrum, which are distant from each other not less than from other species of the genus Lycogala. For 18 of these phylogroups with both 18S rDNA and COI sequences available, recombination patterns were analyzed to test for reproductive isolation. In contrast to the results of a simulation assuming panmixis, no crossing between ribosomal and mitochondrial phylogroups was found, thus allowing the conclusion that all tested phylogroups represent biospecies. More than one third (39.6%) of the studied specimens share a single 18S rDNA phylogroup, which we consider to be L. epidendrum s. str. This group displays the broadest geographic distribution and the highest intraspecific genetic variability. Nearly all (93.3%) of the remaining non-singleton 18S rDNA phylogroups are restricted to certain continents or even regions. At the same time, various reproductively isolated phylogroups occur sympatric at a given location.

Net overboard: Comparing marine eDNA sampling methodologies at sea to unravel marine biodiversity.

Environmental DNA (eDNA) analyses are powerful for describing marine biodiversity but must be optimized for their effective use in routine monitoring. To maximize eDNA detection probabilities of sparsely distributed populations, water samples are usually concentrated from larger volumes and filtered using fine-pore membranes, often a significant cost-time bottleneck in the workflow. This study aimed to streamline eDNA sampling by investigating plankton net versus bucket sampling, direct versus sequential filtration including self-preserving filters. Biodiversity was assessed using metabarcoding of the small ribosomal subunit (18S rRNA) and mitochondrial cytochrome c oxidase I (COI) genes. Multispecies detection probabilities were estimated for each workflow using a probabilistic occupancy modelling approach. Significant workflow-related differences in biodiversity metrics were reported. Highest amplicon sequence variant (ASV) richness was attained by the bucket sampling combined with self-preserving filters, comprising a large portion of microplankton. Less diversity but more metazoan taxa were captured in the net samples combined with 5 μm pore size filters. Prefiltered 1.2 μm samples yielded few or no unique ASVs. The highest average (~32%) metazoan detection probabilities in the 5 μm pore size net samples confirmed the effectiveness of preconcentration plankton for biodiversity screening. These results contribute to streamlining eDNA sampling protocols for uptake and implementation in marine biodiversity research and surveillance.

Molecular and Morphological Characterization of Eimeria crandallis Isolated from Deer (Cervidae) in Different Captive Animals.

Coccidiosis is a protozoan disease that is characterized by diffuse diarrhea, dehydration, emaciation accompanied by moderate morbidity and mild mortality in animals and birds. The current study targeted the molecular characterization of Eimeria isolates in captive deer from different localities in Lahore. The host species was the Cervidae family, such as Hog deer (Axis porcinus) and Punjab urial (Ovis aries vignei). The Eimeria crandallis was isolated from zoo animals. The DNA was extracted from oocysts and amplified by using reported oligonucleotide primers that exhibited the 809 bp product. These were analyzed by using the small subunit 18S rRNA gene-based evolutionary relationship with 36 other Eimeria species reported in caprine, cervinae, bovines, avians, and rodents. Light microscopic examination exhibited 3.29% (7/213) Eimeria-positive fecal samples with morphological features, including sub-spherical forms, the presence of micropyle with polar cap, and oocysts diameters (μm) ranging from 24.32 ± 1.61 to 18.94 ± 1.51. The phylogenetic tree constitutes four distinct clusters with relatively higher values. The evolutionary network showed that sequences were clustered in the monophyletic group of Eimeria species reported in caprine and cervinae. The nucleotide and amino acid sequence similarity matrix analysis exhibited 99.5–99.9% identity of the study isolates with Eimeria crandallis (AF336339). This study provides relevant baseline data to develop strategic control measures for coccidiosis in zoo animals. However, further investigations are required to place the hog deer and Punjab urial-derived E. crandallis into the caprine-originated cluster.

Molecular-based assay for genotyping Leishmania spp. from clinically suspected cutaneous leishmaniasis lesions in the Garmian area, Kurdistan Region of Iraq

Cutaneous leishmaniasis (CL) is highly prevalent in southern Iraq and neighboring countries, but is non-endemic to the Kurdistan Region of Iraq, particularly in the Garmian area. This study aimed to investigate the causative agent of CL at the molecular level by amplifying the small subunit (18S) rRNA and internal transcribed spacer 1 (ITS1) region. The present study was conducted from December 2019 to December 2020 at Kalar General Hospital, Kalar, Kurdistan Region, Iraq. Eighty-five clinical specimens were collected selectively from patients with suspected CL lesions via fine needle aspiration. After parasitic genomic DNA was extracted from the removed fluid, PCR and DNA sequencing targeting the 18S rRNA and ITS1 region were performed for molecular detection and species identification. Additionally, for 14 samples, the target bands of amplified DNA fragments for both 18S rRNA and ITS1 were extracted and sequenced via Sanger method using both the directional primers employed in the PCR. Seventy-one (83.53%) of the 85 suspected patients had CL, based on amplification of 18S rRNA and ITS1 via PCR. The sequence analysis revealed that all samples were Leishmania major. Phylogenetic analysis based on ITS1 was also performed. Our study revealed that our molecular method was an efficient technique for detecting CL and a valuable method for identifying Leishmania species in clinical samples. Sequence analysis indicated that the causative agent of CL in the Garmian area was L. major and the disease was rural in origin.

Txikispora philomaios n. sp., n. g., a micro-eukaryotic pathogen of amphipods, reveals parasitism and hidden diversity in Class Filasterea.

This study provides a morphological, ultrastructural, and phylogenetic characterization of a novel micro-eukaryotic parasite (2.3-2.6µm) infecting amphipod genera Echinogammarus and Orchestia. Longitudinal studies across two years revealed that infection prevalence peaked in late April and May, reaching 64% in Echinogammarus sp. and 15% in Orchestia sp., but was seldom detected during the rest of the year. The parasite infected predominantly hemolymph, connective tissue, tegument, and gonad, although hepatopancreas and nervous tissue were affected in heavier infections, eliciting melanization and granuloma formation. Cell division occurred inside walled parasitic cysts, often within host hemocytes, resulting in hemolymph congestion. Small subunit (18S) rRNA gene phylogenies including related environmental sequences placed the novel parasite as a highly divergent lineage within Class Filasterea, which together with Choanoflagellatea represent the closest protistan relatives of Metazoa. We describe the new parasite as Txikispora philomaios n. sp. n. g., the first confirmed parasitic filasterean lineage, which otherwise comprises four free-living flagellates and a rarely observed endosymbiont of snails. Lineage-specific PCR probing of other hosts and surrounding environments only detected T.philomaios in the platyhelminth Procerodes sp. We expand the known diversity of Filasterea by targeted searches of metagenomic datasets, resulting in 13 previously unknown lineages from environmental samples.

First Molecular Characterisation of Blastocystis from Experimental Rats in Turkey and Comparison of the Frequencies Between Obese and Non-obese Groups

Blastocystis is a zoonotic protozoan that infects a wide range of animals, including humans and rodents. This study aimed to determine the frequency and subtype distribution of Blastocystis in laboratory rats at a laboratory animal facility in Turkey. This study included 54 male Sprague-Dawley rats from Aydın Adnan Menderes University Laboratory Animal Center. Among these rats, 30 were fed with high-fat diet (obese group) and the remaining 24 received standard chow (non-obese group). Blastocystis positivity was determined with amplification of small subunit 18S rRNA gene following their nucleic acid extraction from faecal samples. Subtypes were detected by submitting the partial 18S rRNA gene sequences to the database (pubmlst. Blastocystis infection was detected in 33 (61.1%) of 54 laboratory rats. The frequency of Blastocystis was significantly different between obese and non-obese rats (p<0.05), with 43.3% and 83.3%, respectively. When referred to the database, exact matches were identified with Blastocystis subtype 4 (ST4) for all isolates. In the phylogenetic analysis of the partial 18S rDNA sequence, the sequence was closely clustered with reference ST4 subtypes from other countries, including China, Japan, United Kingdom and Czech Republic. This study revealed the high rate of Blastocystis colonisation in laboratory rats, posing a risk for human transmission. The comparison of obese and non-obese groups supported the idea that Blastocystis might be an indicator of healthy gut flora. The detection of ST4 in all rats agreed with previous reports of the predominance of this subtype in rodents.

Study Entamoeba Species in Livestock by Nested Multiplex PCR in Baghdad City

The aim of the study was to diagnose the Entamoeba spp. in cattle and sheep by using PCR method, foridentified some of these species used the Nested multiplex PCR. The nested multiplex polymerase chainreaction was conducted using the small subunit 18S rRNA gene , the results show total infection rate ofEntamoeba spp was (60%) which include to(30%) in cattle and 30%in sheep. The results second reactionshow that the percent of E.histolytica was (30%) in cattle and (30%) in sheep

Diplotriaena obtusa infection in an Eurasian blue tit (Cyanistes caeruleus) in Germany. Pathology and phylogenetic analysis

Diplotriaena obtusa is a nematode found in air sacs of a wide number of birds, including Passerine species. During a period of increased mortality of blue tits (Cyanistes caeruleus) in Germany, we collected adult nematode worms from the air sacs of a deceased male blue tit. The nematodes showed morphological features consistent with Diplotriaena ssp. A polymerase chain reaction (PCR) assay targeting the small subunit (SSU) 18S rRNA gene identified the parasite species as Diplotriaena obtusa. Phylogenetic analysis confirmed species identification. Further examinations against infectious pathogens like Suttonella ornithocola, Salmonella spp., Pasteurella spp., Chlamydia spp., Influenza A virus, Usutu virus and West Nile virus were negative. This is the first report of D. obtusa in a blue tit from Germany.

First record of a marine microalgal species, &lt;i&gt;Jaagichlorella roystonensis&lt;/i&gt; (Trebouxiophyceae) isolated from Jungmun Saekdal Beach, Jeju Island, Korea

A eukaryotic marine microalga was isolated from Jungmun Saekdal Beach, Jeju Island, Korea and an integrated approach, including molecular phylogeny and morphology, was used to determine its taxonomical status. Molecular phylogenetic evidence inferred from the small subunit (SSU) 18S rRNA sequence and internal transcribed spacer (ITS) secondary structure analysis clearly showed that the isolate belonged to the recently described species, Jaagichlorella roystonensis. Distinctive morphological keys of the species were also observed by light microscopy and scanning/ transmission electron microscopy (S/TEM). In this study, a Korean marine J. roystonensis species was described for the first time and was subsequently added to the national culture collections in Korea.

Distribution of Cryptosporidium species isolated from diarrhoeic calves in Japan.

Cryptosporidium spp. are enteric protozoan parasites that infect a wide range of hosts including humans, and domestic and wild animals. The aim of this study was to molecularly characterize the Cryptosporidium spp. found in calf faeces in Japan. A total of 80 pre-weaned beef and dairy calves' diarrhoeic faecal specimens were collected from nine different prefectures in Japan. A nested polymerase chain reaction targeting the small subunit 18S rRNA and GP60 genes were used to detect the Cryptosporidium genotypes and subtypes. 83.8% (67 out of 80) of the specimens were positive for Cryptosporidium spp.; Cryptosporidium was found in both beef and dairy calves. Cryptosporidium parvum was the predominant species, detected in 77.5% (31/40) of beef calves and 80% (32/40) of dairy calves. Cryptosporidium bovis was also detected, 5.0% (2/40) of dairy calves, and C. ryanae was also found 2.5% (1/40) of dairy calves. One mixed-species infection, 2.5% (1/40) was detected in a beef calf having C. parvum, and C. ryanae. We detected the most common subtype of C. parvum (i.e., IIaA15G2R1), as well as other subtypes (i.e., IIaA14G3R1, IIaA14G2R1, and IIaA13G1R1) that have not previously been detected in calves in Japan. Our results demonstrate the widespread diversity of Cryptosporidium infection in calves in Japan.

First record of a marine microalgal species, &lt;i&gt;Micractinium singularis&lt;/i&gt; (Trebouxiophyceae) isolated from Janghang Harbor, Korea

A eukaryotic microalga was isolated from seawater in Janghang Harbor, Korea and its morphological, molecular, and physiological characteristics were investigated. Due to its simple morphology, no distinctive characters were found by morphological observation, such as light microscope or scanning/transmission electron microscopy (S/ TEM). However, molecular phylogenetic evidence inferred from the concatenated small subunit (SSU) 18S rRNA and internal transcribed spacer (ITS) sequence data indicated that the isolate belonged to the newly described Micractinium singularis. Furthermore, it was clustered with Antarctic Micractinium strains and it also showed a psychrotolerant property, surviving at temperatures as low as 5°C. However, its optimal growth temperatures range from 15°C to 25°C, indicating that this microalga is a mesophile. Additionally, gas chromatography-mass spectrometry (GC/MS) analysis showed that the isolate was rich in nutritionally important omega-3 polyunsaturated fatty acid, and high-performance liquid chromatography analysis (HPLC) revealed that the high-value antioxidant lutein was biosynthesized as an accessory pigment by this microalga, with glucose as the major monosaccharide. Therefore, in this study, a Korean marine M. singularis species was discovered, characterized, and described. It was subsequently added to the national culture collections.

Confirmation of the shell-boring oyster parasite Polydora websteri (Polychaeta: Spionidae) in Washington State, USA

Invasions by shell-boring polychaetes such as Polydora websteri Hartman have resulted in the collapse of oyster aquaculture industries in Australia, New Zealand, and Hawaii. These worms burrow into bivalve shells, creating unsightly mud blisters that are unappealing to consumers and, when nicked during shucking, release mud and detritus that can foul oyster meats. Recent findings of mud blisters on the shells of Pacific oysters (Crassostrea gigas Thunberg) in Washington State suggest a new spionid polychaete outbreak. To determine the identity of the polychaete causing these blisters, we obtained Pacific oysters from two locations in Puget Sound and examined them for blisters and burrows caused by polychaete worms. Specimens were also obtained from eastern oysters (Crassostrea virginica Gmelin) collected in New York for morphological and molecular comparison. We compared polychaete morphology to original descriptions, extracted DNA and sequenced mitochondrial (cytochrome c oxidase I [mtCOI]) and nuclear (small subunit 18S rRNA [18S rRNA]) genes to determine a species-level molecular identification for these worms. Our data show that Polydora websteri are present in the mud blisters from oysters grown in Puget Sound, constituting the first confirmed record of this species in Washington State. The presence of this notorious invader could threaten the sustainability of oyster aquaculture in Washington, which currently produces more farmed bivalves than any other US state.

Taxonomical considerations and molecular phylogeny of the closely related genera Bitylenchus, Sauertylenchus and Tylenchorhynchus (Nematoda: Telotylenchinae), with one new and four known species from Iran.

During several nematological surveys in cultivated and natural habitats in Khuzestan and Zanjan provinces of Iran, a new species, Bitylenchus parvulus n. sp., two new records for Iran - namely, Tylenchorhynchus agri and Tylenchorhynchus graciliformis - and a population of Bitylenchus parvus and one of Sauertylenchus maximus were recovered and characterized based upon morphological and molecular approaches. The new species is characterized by lip region with five to seven annuli, stylet 17.7 (17.0-18.5) μm long, sub-cylindrical tail narrowing abruptly near terminus giving a bluntly digitate shape to the tail tip, cuticle near anterior part of vulva wrinkled and post-rectal sac occupies whole of tail cavity. The phylogenetic analyses were carried out using molecular data from D2-D3 expansion segments of large ribosomal subunit (28S rRNA) for all studied species and the partial small ribosomal subunit (18S rRNA) for the new species. The representatives of Bitylenchus and Sauertylenchus formed distinct clades from Tylenchorhynchus members, supporting the hypothesis in which Bitylenchus and Sauertylenchus could be considered as valid genera, but rejecting the 'large-genus' concept for Tylenchorhynchus. Also, Sauertylenchus ibericus was proposed as a junior synonym of S. maximus based on the results from morphological and phylogenetic analysis. Furthermore, an identification key for all known species included in the three genera Bitylenchus, Tylenchorhynchus and Sauertylenchus is presented herein. The number of transverse annuli on the lip region and presence/absence of post-rectal sac were considered as the main diagnostic characters for classifying the species into seven groups, and other morphological and morphometric characters were subsequently used for distinguishing species in each group.