SSU rRNA Gene Research Articles

Unexpected Genetic Diversity of Nostocales (Cyanobacteria) Isolated from the Phyllosphere of the Laurel Forests in the Canary Islands (Spain)

A total of 96 strains of Nostocales (Cyanobacteria) were established from the phyllosphere of the laurel forests in the Canary Islands (Spain) and the Azores (Portugal) using enrichment media lacking combined nitrogen. The strains were characterized by light microscopy and SSU rRNA gene comparisons. Morphologically, most strains belonged to two different morphotypes, termed “Nostoc-type” and “Tolypothrix-type”. Molecular phylogenetic analysis of 527 SSU rRNA gene sequences of cyanobacteria (95 sequences established during this study plus 392 sequences from Nostocales and 40 sequences from non-heterocyte-forming cyanobacteria retrieved from the databases) revealed that none of the SSU rRNA gene sequences from the phyllosphere of the laurel forests was identical to a database sequence. In addition, the genetic diversity of the isolated strains was high, with 42 different genotypes (44% of the sequences) recognized. Among the new genotypes were also terrestrial members of the genus Nodularia as well as members of the genus Brasilonema. It is concluded that heterocyte-forming cyanobacteria represent a component of the phyllosphere that is still largely undersampled in subtropical/tropical forests.

Prevalence and genetic diversity of Giardia duodenalis in sheep from large-scale farms in Southern Xinjiang, China

Giardia duodenalis is a significant zoonotic parasite. In this study, 767 fresh fecal samples were collected randomly from six large-scale sheep farms in Southern Xinjiang, China. Initially, G. duodenalis was screened using PCR at the SSU rRNA gene. Positive samples then underwent PCR amplification at the bg, gdh, and tpi genes. The prevalence of G. duodenalis in sheep was 17.5% (134/767), with the highest prevalence observed in the 3-6 months age group at 26.8% (56/209) and the lowest in the over 12 months age group at 6.8% (14/205). Among the 134 positive samples, only Assemblage E was identified. A total of 106, 92, and 98 sequences of G. duodenalis were obtained at the gdh, tpi, and bg genes, respectively. Fourteen isolates of G. duodenalis were successfully amplified at all three genes, resulting in nine G. duodenalis multilocus genotypes (MLG) named MLG E1-MLG E14, indicating high genetic diversity. In conclusion, G. duodenalis infection in sheep from large-scale farms is common in Southern Xinjiang, China, showing geographical regional distributions and genetic diversity.

Exophiala zingiberis sp. nov., a novel cellulase-producing black yeast-like fungi isolated from ginger in India.

The genus Exophiala, known for its melanized, yeast-like appearance, includes a diverse group of fungi with significant implications across various fields. An isolate representing a novel species was identified within this genus from a ginger tuber from India, based on morphological characteristics and molecular phylogenetic analysis. Phylogenetic analysis of the D1/D2 domain of the 26S LSU rRNA gene, SSU rRNA gene and the internal transcribed spacer (ITS) region confirmed this strain as a new species. It was named Exophiala zingiberis sp. nov. (MycoBank no. MB 855415), with MCC 9960T designated as the holotype and PYCC 9834 as the isotype. Exophiala zingiberis was positioned as a sister species to a clade that includes Exophiala castellanii, Exophiala mali and three additional species. Phylogenetic analysis indicates that while E. zingiberis shares a common ancestor with these species, it is genetically distinct, underscoring its novel status. The type strain of this novel species differs from Exophiala yuxiensis YMF1.07354T, the most closely related species, by 19 nucleotide substitutions (3.6% sequence variation) in the D1/D2 region (549 bp compared) and 104 nucleotide substitutions and 44 gaps (27.1% sequence variation) in the ITS region (546 bp compared).

Gonyaulax montresoriae sp. nov. (Dinophyceae) from the Adriatic Sea produces predominantly yessotoxin

Yessotoxin is one of the shellfish toxins leading to mussel farm closures in the Adriatic Sea of Italy. Two putative Gonyaulax spinifera strains GSA0501 and GSA0602 are known as yessotoxins producers, but their identities have remained elusive since 2005. To address this gap, we established five Gonyaulax strains by incubating sediments from the Adriatic Sea and subsequently isolating single cells. Both cyst and theca morphology were examined using light and scanning electron microscopy. In addition, LSU and/or SSU rRNA gene sequences were obtained for all strains. Two strains produce cysts resembling Spiniferites mirabilis and one strain was related to S. scabratus. The other two strains are described as Gonyaulax montresoriae sp. nov., characterized by a high cingular displacement and overhang, along with two unequal antapical spines. Cysts of G. montresoriae are pear-shaped, showing a smooth surface and exclusively gonal processes with perforations at the base, the latter similar to S. lazus. LSU rRNA gene sequence comparison suggests that the G. spinifera strain GSA0501 isolated from the Adriatic Sea in 2005 should also be identified as G. montresoriae. Maximum likelihood and Bayesian inference analyses based on LSU and SSU rRNA gene sequences reveal that G. montresoriae is monophyletic, and close to several toxic strains of presumable Gonyaulax spinifera from the Adriatic Sea and New Zealand, whose taxonomic positions are uncertain. One strain of G. montresoriae was examined for yessotoxin production using LC-MS/MS, and found to produce predominantly yessotoxin at a concentration of 3.0 pg cell-1. Our results highlight the rich diversity and risks associated with Gonyaulax species in the Mediterranean Sea.

Molecular Assessment of Blastocystis hominis in Patients with Diabetes Mellitus in Balad City, Saladin Province, Iraq

Abstract Background: Blastocystis sp. is the most prevalent intestinal protozoa found worldwide in both humans and animals. Objectives: This study aims to identify the subtypes of Blastocystis sp. parasite isolated from diabetes mellitus patients using molecular techniques such as polymerase chain reaction (PCR), DNA sequencing, and phylogenetic analysis. Materials and Methods: The current study was conducted on samples collected from a total of 300 patients (150 diabetic patients and 150 non-diabetic patients). The samples were taken between November 2022 and May 2023 at the laboratories of the General Balad Hospital in Balad City, Saladin, Iraq. Blood and stool samples were taken from each patient, and the investigation included microscopic examination and culturing of the samples on Modified Jones’ Medium for parasitic identification; active infection was confirmed genetically using PCR, and subtyping was done via sequencing of the SSU rRNA gene. Results: Microscopically, only 80 diabetic patients (50 males and 30 females) were infected with Blastocystis hominis, and only 50 people (13 males and 37 females) among the healthy participants had B. hominis infection. Thirty samples were further studied using PCR, and only 16 showed clear bands on the gel, whereas only eight samples were successfully sequenced. Conclusion: This study demonstrated that diabetic mellitus patients (DM group) had a higher prevalence of B. hominis infection compared to the non-DM group. Furthermore, there is a link between the presence of Blastocystis and other risk factors, such as place of residence, water source, and keeping animals, which suggests that exposure to animal stools may result in the development of Blastocystis ST1 among the studied participants.

Clinical Manifestations and Molecular Identification of Giardia duodenalis in Pediatric and Adolescent Cancer Patients in Southwestern Iran.

This study aimed to investigate the clinical and molecular characteristics of Giardia duodenalis (G. duodenalis) infection and identify potential risk factors in children and teenagers with malignancies in Shiraz, southwestern Iran. A total of 200 fresh fecal samples were collected from children and adolescents suffering from 32 different cancer types at Amir, Nemazee, and Saadi hospitals affiliated with Shiraz University of Medical Sciences between October 2021 and May 2022. Direct microscopy using saline and iodine wet mount was conducted, and all fecal samples were rechecked by SSU-PCR. Subsequently, a specific fragment of the tpi gene was amplified on all samples for prevalence, sequencing, and assemblage identification. Our study found a 4% (8/200) prevalence of G. duodenalis using microscopy and PCR. The molecular findings were consistent with the microscopic results. All eight positive samples with SSU-rRNA gene were also detected as positive with tpi gene and were correctly sequenced. Among the examined cancer patients, two assemblages were identified: A [sub-assemblage AI (2/8, 25%) and sub-assemblage AII (3/8, 37.5%)] and B [sub-assemblage BIV (3/8, 37.5%)]. Notably, patients were more vulnerable to G. duodenalis infection after receiving at least 8 treatment episodes (p < 0.05) and displaying gastrointestinal symptoms (p > 0.05). The demographic characteristics of cancer patients with G. duodenalis infection and the statistical conclusions were separately detailed. The small sample size and low prevalence rate in this study hindered precise epidemiological conclusions. Nonetheless, the results suggest that G. duodenalis infection among cancer patients in Shiraz city originates from humans, without any specific animal groups (C-H) involved.

Environmental surveillance of Cryptosporidium and Giardia in surface supply water and treated sewage intended for reuse from an urban area in Brazil

Environmental monitoring of protozoa, with the potential to trigger diseases, is essential for decision-making by managing authorities and for the control of water surveillance. This study aimed to detect and quantify Cryptosporidium oocysts and Giardia cysts in surface water for drinking water supply and treated sewage for reuse in the city of São Paulo. Samples collected bimonthly for one year were concentrated using the USEPA 1623.1 and 1693 methods for surface water and treated effluents, respectively. Immunofluorescence and nucleic acid amplification techniques were used to detect and quantify (oo)cysts. The cloning technique followed by sequencing and phylogenetic analyses were performed to characterize species and genotypes. The immunofluorescence detected Cryptosporidium spp. and Giardia spp. in 69.2% (9/13) and 100% (13/13) of the surface water samples (0.1–41 oocysts/L and 7.2–354 cysts/L, respectively). In the reuse samples, 85.7% (12/14) were positive for both protozoa and the concentrations varied from 0.4 to 100.6 oocysts/L and 1.2 and 93.5 cysts/L. qPCR assays showed that 100% of surface water (0.1–14.6 oocysts/L and 0.3–639.8 cysts/L) and reused samples (0.1–26.6 oocysts/L and 0.3–92.5 cysts/L) were positive for both protozoa. Species C. parvum, C. hominis, and C. muris were identified using the 18S rRNA gene, demonstrating anthroponotic and zoonotic species in the samples. Multilocus SSU rRNAanalyses of the SSU rRNA, tpi, and gdh genes from Giardia intestinalis identified the AII, BII, and BIV assemblages, revealing that contamination in the different matrices comes from human isolates. The study showed the circulation of these protozoa in the São Paulo city area and the impairment of surface water supply in metropolitan regions impacted by the discharge of untreated or inadequately treated sewage regarding the removal of protozoa, emphasizing the need to implement policies for water safety, to prevent the spread of these protozoa in the population.

Cryptosporidium species and subtypes in Norway: Predominance of C. parvum and emergence of C. mortiferum

PCR-based diagnostics has revealed the previously largely unknown Cryptosporidium transmission and infections in high-income countries. This study aimed to determine domestic and imported subtypes of Cryptosporidium species in Norway, evaluate their demographic distribution, and identify potential small outbreaks. Cryptosporidium-positive human faecal samples were obtained from six medical microbiology laboratories between February 2022 and January 2024, together with 22 Cryptosporidium-positive animal samples. Species and subtypes were identified by sequencing PCR products from gp60 and SSU rRNA genes. Most cryptosporidiosis cases occurred during late summer/early autumn, primarily in children and young adults. Of 550 human samples, 359 were successfully characterized molecularly (65%), revealing infection with 10 different Cryptosporidium species. C. parvum occurred in 245 (68%) human isolates with IIa and IId being major allele families, with distinct regional distribution patterns of common subtypes. A kindergarten outbreak with 5 cases was due to C. parvum IIaA14G1R1. C. mortiferum was identified in 33 (9.2%) human cases of which 24 were known to be of domestic origin, making it the second most common species in human autochthonous cases in Norway. All C. mortiferum isolates were of the same genotype; XIVaA20G2T1, including 13 cases from a suspected small outbreak in Trøndelag. C. hominis occurred in 68 typed cases (19%), but mostly in infections acquired abroad, with allele families Ib and If occurring most often. In conclusion, this study of recent Cryptosporidium spp. and subtypes in Norway, highlights the predominance of C. parvum and the emergence of C. mortiferum among autochthonous cases.

Biogeographic shifts in the microbial co-occurrence network features of three domains across complex environmental gradients in subtropical coastal waters

BackgroundBacteria, Archaea, and Microeukaryotes comprise taxonomic domains that interact in mediating biogeochemical cycles in coastal waters. Many studies have revealed contrasting biogeographic patterns of community structure and assembly mechanisms in microbial communities from different domains in coastal ecosystems; however, knowledge of specific biogeographic patterns on microbial co-occurrence relationships across complex coastal environmental gradients remains limited. Using a dense sampling scheme at the regional scale, SSU rRNA gene amplicon sequencing, and network analysis, we investigated intra- and inter-domain co-occurrence relationships and network topology-based biogeographic patterns from three microbial domains in coastal waters that show environmental gradients across the inshore-nearshore-offshore continuum in the East China Sea.ResultsOverall, we found the highest complexity and connectivity in the bacterial network, the highest modularity in the archaeal network, and the lowest complexity, connectivity, and modularity in the microeukaryotic network. Although microbial co-occurrence networks from the three domains showed distinct topological features, they exhibited a consistent biogeographic pattern across the inshore-nearshore-offshore continuum. Specifically, the nearshore zones with intermediate levels of terrestrial impacts reflected by multiple environmental factors (including water temperature, salinity, pH, dissolved oxygen, and nutrient-related parameters) had a higher intensity of microbial co-occurrence for all three domains. In contrast, the intensity of microbial co-occurrence was weaker in both the inshore and the offshore zones at the two ends of the environmental gradients. Archaea occupied a central position in the microbial inter-domain co-occurrence network. In particular, members of the Thaumarchaeota Marine Group I (MGI, now placed within the Family Nitrosopumilaceae of the Phylum Thermoproteota) appeared to be the hubs in the biogeographic shift between inter-domain network modules across environmental gradients.ConclusionsOur work offers new insights into microbial biogeography by integrating network features into biogeographic patterns, towards a better understanding of the potential of microbial interactions in shaping biogeographic patterns of coastal marine microbiota.

Prevalence and molecular characterization of Cryptosporidium spp. in pre-weaned diarrheic dairy calves and their bedding materials in northern China.

Cryptosporidiosis, primarily caused by Cryptosporidium parvum, is a significant cause of diarrhea in pre-weaned dairy calves. To investigate the prevalence of Cryptosporidium among pre-weaned diarrheic dairy calves and identify potential sources of infection in northern China, 234 fecal samples from 18 farms in six regions were analyzed for Cryptosporidium. Furthermore, 217 bedding samples from both occupied and unoccupied calf hutches, heating lamp pens, and individual calving pens in eight farms in Beijing were also examined for the presence of the parasite. All samples were screened for Cryptosporidium spp. using nested PCR targeting the SSU rRNA gene fragment, and C. parvum was subtyped with nested PCR targeting the 60kDa glycoprotein gene. The prevalence of Cryptosporidium was 33.3%, with C. parvum and C. bovis constituting 29.9% and 3.4% of cases, respectively. The positive rate of Cryptosporidium in 1- to 4-week-old calves ranged from 9.6 to 63.6%. Analysis of the gp60 fragment of C. parvum revealed four subtypes: IIdA15G1, IIdA17G1, IIdA19G1, and IIdA20G1. Besides the bedding samples in heating lamp pens, both C. parvum and C. bovis were detected in bedding samples throughout the other regions. A significant positive correlation between the detection rate of Cryptosporidium in fecal samples and that in the bedding materials of occupied calf hutches (R = 0.93, P = 0.002). These findings suggest that C. parvum is the predominant species among pre-weaned diarrheic dairy calves in northern China. Contaminated bedding materials may act as sources of infection for newborn calves.

Molecular Typing of Cryptosporidium in Cattle in Federal Capital Territory, Nigeria

Cryptosporidium is an enteric pathogen with worldwide distribution in humans and animals with cattle as their reservoirs. Molecular tools have been very useful in determining the epidemiology of this zoonotic pathogen of public health importance. Despite the importance of this pathogen to humans and animals, there is limited published information on the risk factors of its epidemiology in the Federal Capital Territory of Nigeria. Positive faecal samples of 400 cattle in 46 farms located in 6 area councils of the FCT that were earlier screened for Cryptosporidium on light microscopy were genotyped by nested PCR using primers that targeted 18S ssUrRNA gene and followed by RFLP. The PCR-RFLP products were further sub genotyped by nested PCR and GP 60 KDa gene amplification. The nucleotides of the amplicons were subsequently sequenced. The overall PCR detection rate was 5.5%. Analysis of the 18S rRNA gene of the PCR-RFLP fragments revealed Cryptosporidium ryanae (18.3%), C. andersoni (8.5%) and C. parvum (4.2%). Analysis of the nucleotide sequence of the GP 60KDa gene of all the C. parvum detected showed all to be 100% subtype family IIa and 100% sub genotype IIaA18G3R1. In conclusion, this study has established the presence of Cryptosporidium in cattle in the FCT. The detection of the zoonotic C. parvum, its subtype IIa and its allele IIaA18G3R1 is an indication of source of zoonotic transmission of the parasite in the FCT, Nigeria.

Prevalence and Subtypes Distribution (ST10, ST14, ST25, ST26) of Blastocystis spp. in Anatolian Water Buffalo (Bubalus bubalis) in Van, Türkiye.

Blastocystis spp. is one of the most common protozoa worldwide, living in the gastrointestinal tract of humans and many other animals. On the basis of the genetic heterogeneity of small subunit ribosomal RNA, at least 28 subtypes (ST1-ST17, ST21 and ST23-ST32) are reported to exist in mammals and birds. This study was carried out to determine the prevalence and subtypes of Blastocystis spp. in Anatolian buffaloes (Bubalus bubalis) in Van province in the Eastern Anatolia Region of Turkey. DNA was extracted using commercial GeneMATRIX Stool DNA Purification Kit and then stored at -20°C until PCR amplification. After PCR amplification of the SSU rRNA gene region positive Blastocystis spp., amplicons from buffalo faeces were sequenced and then deposited in GenBank (OR576949.1, OR576950.1, OR576970.1, OR576971.1, OR577019.1, PP837943.1, PP837940.1, PP837939.1, PP837604.1, PP837937.1, PP837934.1, PP837601.1, PP837936.1 and PP837603.1). PCR analysis of 120 faecal samples showed a total prevalence of 11.67% (14/120). The prevalence was higher in females and young animals (p>0.05). Sequence analysis revealed Blastocystis spp., ST10, ST14, ST25 and ST26 subtypes. To our knowledge, Blastocystis subtypes ST25 and ST26 in buffaloes were reported for the first time in this study. It is thought that more large-scale studies should be carried out to determine the zoonotic subtype potential of this protozoan in the region.

O short-branch Microsporidia, where art thou? Identifying diversity hotspots for future sampling

Short-branch Microsporidia were previously shown to form a basal grade within the expanded Microsporidia clade and to branch near the classical, long-branch Microsporidia. Although they share simpler versions of some morphological characteristics, they do not show accelerated evolutionary rates, making them ideal candidates to study the evolutionary trajectories that have led to long-branch microsporidian unique characteristics. However, most sequences assigned to the short-branch Microsporidia are undescribed, novel environmental lineages for which the identification requires knowledge of where they can be found. To direct future isolation, we used the EukBank database of the global UniEuk initiative that contains the majority of the publicly available environmental V4 SSU rRNA gene sequences of protists. The curated OTU table and corresponding metadata were used to evaluate the occurrence of short-branch Microsporidia across freshwater, hypersaline, marine benthic, marine pelagic, and terrestrial environments. Presence–absence analyses infer that short-branch Microsporidia are most abundant in freshwater and terrestrial environments, and alpha- and beta-diversity measures indicate that focusing our sampling effort on these two environments would cover a large part of their overall diversity. These results can be used to coordinate future isolation and sampling campaigns to better understand the enigmatic evolution of microsporidians’ unique characteristics.

Complex hydrothermal vent microbial mat communities used to assess primer selection for targeted amplicon surveys from Kama‘ehuakanaloa Seamount

The microbiota of hydrothermal vents has been widely implicated in the dynamics of oceanic biogeochemical cycling. Lithotrophic organisms utilize reduced chemicals in the vent effluent for energy, which fuels carbon fixation, and their metabolic byproducts can then support higher trophic levels and high-biomass ecosystems. However, despite the important role these microorganisms play in our oceans, they are difficult to study. Most are resistant to culturing in a lab setting, so culture-independent methods are necessary to examine community composition. Targeted amplicon surveying has become the standard practice for assessing the structure and diversity of hydrothermal vent microbial communities. Here, the performance of primer pairs targeting the V3V4 and V4V5 variable regions of the SSU rRNA gene was assessed for use on environmental samples from microbial mats surrounding Kama‘ehuakanaloa Seamount, an iron-dominated hydrothermal vent system. Using the amplicon sequence variant (ASV) approach to taxonomic identification, the structure and diversity of microbial communities were elucidated, and both primer pairs generated robust data and comparable alpha diversity profiles. However, several distinct differences in community composition were identified between primer sets, including differential relative abundances of both bacterial and archaeal phyla. The primer choice was determined to be a significant driver of variation among the taxonomic profiles generated. Based on the higher quality of the raw sequences generated and on the breadth of abundant taxa found using the V4V5 primer set, it is determined as the most efficacious primer pair for whole-community surveys of microbial mats at Kama‘ehuakanaloa Seamount.

Octomacrum spinum (Monogenoidea: Polyopisthocotylea: Octomacridae) from highland stoneroller, Campostoma spidaceum (Cypriniformes: Leuciscidae) from Arkansas and Oklahoma, USA, with a summary of the genus from North American and European fishes.

Octomacrum spinum Dansby & Shoemaker, 1973, is reported for the first time from 23 of 146 (16%) highland stonerollers, Campostoma spadiceum collected from central and western Arkansas and southeastern Oklahoma, USA. Analysis of molecular data revealed that the SSU rRNA gene of specimens of O. spinum from Arkansas was identical to a number of Octomacrum spp. and the LSU rRNA gene was 97.46% similar to Octomacrum europaeum. We also provide a summary of the species of Octomacrum reported from North American and European fishes.

Oxyplasma meridianum gen. nov., sp. nov., an extremely acidophilic organotrophic member of the order Thermoplasmatales.

A mesophilic, hyperacidophilic archaeon, strain M1T, was isolated from a rock sample from Vulcano Island, Italy. Cells of this organism were cocci with an average diameter of 1 µm. Some cells possessed filaments. The strain grew in the range of temperatures between 15 and 52 °C and pH 0.5-4.0 with growth optima at 40 °C and pH 1.0. Strain M1T was aerobic and chemoorganotrophic, growing on complex substrates, such as casamino acids, trypticase, tryptone, yeast and beef extracts. No growth at expenses of oxidation of elemental sulphur or reduced sulphur compounds, pyrite, or ferrous sulphate was observed. The core lipids were glycerol dibiphytanyl glycerol tetraether lipids (membrane spanning) with 0 to 4 cyclopentane moieties and archaeol, with trace amounts of hydroxy archaeol. The dominant quinone was MK-7 : 7. The genome size of M1T was 1.67 Mbp with a G+C content of 39.76 mol%, and both characteristics were well within the common range for Thermoplasmatales. The phylogenetic analysis based on 16S rRNA gene sequence placed the strain M1T within the order Thermoplasmatales with sequence identities of 90.9, 90.3 and 90.5% to the closest SSU rRNA gene sequences from organisms with validly published names, Thermoplasma acidophilum, Thermoplasma volcanium and Thermogymnomonas acidicola, respectively. Based on the results of our genomic, phylogenetic, physiological and chemotaxonomic studies, we propose that strain M1T (=DSM 116605T=JCM 36570T) represents a new genus and species, Oxyplasma meridianum gen. nov., sp. nov., within the order Thermoplasmatales.

Taxonomy and molecular phylogeny of genus Plagiocampa (Ciliophora, Prostomatea), with redescriptions of two poorly known species

Prostomateans, as common inhabitants in diverse aquatic environments, are among the simplest ciliate lineages, and serve as trophic links in food webs. However, only a few members are well-known and thoroughly studied, and the diversity of this group remains elusive. The unique genus Plagiocampa has a long history of research, but few studies have been performed using up-to-date methods. In the present work, Plagiocampa longis Kahl, 1927 and Plagiocampa minima Kahl, 1927, collected from Chinese coastal habitats, were investigated based on microscopical observation, protargol staining, and SSU rRNA gene sequencing. Their ciliature and morphometric data as well as gene sequences are documented. Phylogenetic analyses revealed that the family Plagiocampidae is likely monophyletic and has a closer relationship with parasitic Cryptocaryon.

Paospora carinifang n. gen., n. sp. (Microsporidia: Spragueidae), a parasite of the ridgetail white prawn, Palaemon carinicauda

A new microsporidian disease of the pond-reared ridgetail white prawn, Palaemon carinicauda, was found in China. Light microscopy, pathology, and scanning electron microscopy showed that the parasite infected the host’s skeletal muscle tissue and formed spherical sporophorous vesicles (SPOVs). Electron microscopy revealed that its merogonic life stages developed in direct contact with the host cytoplasm. The sporogonic life stages underwent octosporoblastic sporogony with the formation of eight uninucleate spores in each SPOV. Fresh SPOVs were 5.4 ± 0.55 µm in diameter. The octospores were oval and measured 2.3 × 1.5 μm (fresh) and 1.96 × 1.17 μm (fixed). The isofilar polar filament was coiled with 9–10 turns and arranged in two rows. Phylogenetic analysis based on the SSU rRNA gene suggests that this microsporidium has close affinities with members of the genera Potaspora and Apotaspora, but represents an independent generic taxon. We therefore propose the establishment of a new genus and species (Paospora carinifang n. gen., n. sp.) within the family Spragueidae. We also propose a taxonomic revision to transfer Potaspora macrobrachium to this new genus and reclassify it as Paospora macrobrachium comb. nov.

Redescription of two Euplotes species (Ciliophora, Euplotida) from Yangtze River Estuary, China, with a note on the distributions of this genus in China

Ciliates are important unicellular organisms in the studies of biomolecules, genetics, and evolution. Euplotids are a highly diversified and widely distributed group. The morphology of two euplotids, Euplotes dominicanus and E. parkei, isolated from the Yangtze River Estuary, China, were investigated based on live observation, protargol-, and Chatton-Lwoff staining methods. The Chinese population of E. dominicanus resembles the original abyssal population except for having two caudal cirri and seven dorsolateral kineties. The Chinese population of E. parkei corresponds well with the original description in size, having eight frontoventral cirri, two marginal cirri, and a double-eurystomus dorsal silverline system. The diagnoses were improved by incorporating newly obtained data, detailed illustrations, and photomicrographs were supplemented. Euplotes parkei sensu needs to be reinvestigated. Phylogenetic analyses based on SSU rRNA gene sequence data confirmed the branching position of the two taxa within the genus Euplotes. The geographical distribution of the genus Euplotes in China was also briefly reviewed, and further exploration is needed in the brackish habitat, particularly focusing on the estuary zone.

Molecular characterizations of Cryptosporidium spp. in brown rat (Rattus norvegicus) from an animal feedlot in Xinjiang, China.

Cryptosporidium infection is a common occurrence in rodents worldwide. In this study, 435 wild brown rats were captured from an animal feedlot in Xinjiang, China, with a fecal sample obtained directly from the rectal contents of each rat. The DNA extracted from these fecal samples was analyzed for Cryptosporidium spp. using PCR targeting the SSU rRNA gene. The prevalence of Cryptosporidium infection in brown rats was found to be 5.5% (24 out of 435). Interestingly, the infection rates varied among different animal enclosures, with rates of 0% in the chicken coop (0/51), cowshed (0/3), and varying rates in other areas including the sheepfold (6.1%, 6/98), the pigsty (7.6%, 10/132), the dovecote (7.0%, 5/71), and outdoor environments (3.8%, 3/80). The study identified three species and one genotype of Cryptosporidium, namely C. occultus (n = 10), C. parvum (n = 4), C. ditrichi (n = 1), and Cryptosporidium rat genotype IV (n = 9). Additionally, two of the C. parvum isolates were successfully subtyped as IIdA19G1 (n = 2) at the gp60 gene. These results offer valuable insights into the prevalence and genetic diversity of Cryptosporidium in brown rats within the region.