Partial 16S rDNA Research Articles

A new needle nematode, Longidorus maginicus n. sp. (Nematoda: Longidoridae) from southern Spain.

During nematode surveys in natural vegetation in Sierra Mágina, Jaén province, southern Spain, a Longidorus species closely resembling Longidorus carpetanensis was found, but application of integrative taxonomic approaches clearly demonstrated that it is a new species described herein as Longidorus maginicus n. sp. The new species is amphimictic, characterized by a moderately long body (4.2-5.2 mm); lip region anteriorly flattened, slightly separated from the rest of body by a depression, 9.0-11.0 μm wide and 3.5-6.0 μm high; amphidial fovea not lobed; relatively short odontostyle (61.0-70.5 μm); guiding ring located 23.5-27.0 μm from anterior end; vulva located at 42.0%-51.3% of body length; female tail 39.0-61.0 μm long, conoid, dorsally convex with rounded terminus (c' = 1.3-2.1), with two or three pairs of caudal pores; and males common (1:2 ratio males:females), with moderately long spicules (39.0-48.5 μm) and 1 + 6-9 ventromedian supplements and three juvenile developmental stages. According to the polytomous key, codes for the new species are (codes in parentheses are exceptions): A2-B1-C2-D2-E1-F2(3)-G2-H5(4)-I2-J1-K6. The results of molecular analysis of D2-D3 28S, internal transcribed spacer region, partial 18S rDNA, and cytochrome oxidase c subunit 1 (coxI) gene sequences further characterized the new species status, and separated it from L. carpetanensis and other related species.

Temnosewellia aff. vietnamensis (Platyhelminthes: Rhabdocoela: Temnocephalidae) associated with freshwater crabs from Kagoshima, southern Japan, with review of records of the genus from East to South Asian countries.

Temnocephalids are ectosymbionts of various freshwater animals. A species tentatively identified as Temnosewellia aff. vietnamensis (Platyhelminthes: Rhabdocoela: Temnocephalidae) is reported based on materials collected from the body surface of the freshwater crabs Eriocheir japonica (Brachyura: Varunidae) and Geothelphusa exigua (Potamidae) in Kagoshima, southern Japan. The temnocephalid is characterized as follows: the cirrus composed of a cone-shaped shaft and a cylindrical introvert 42-77 μm long; the introvert covered with approximately 30 vertical rows of fine sharp spines; the four seminal receptacles; and a long, curved oviduct with vaginal gland; a pair of gland cells (Haswell's cells) present anterior to the excretory ampullae. Bayesian inference trees using partial nuclear 28S rDNA (28S) and mitochondrial cytochrome c oxidase subunit I (COI) genes supported that the specimens collected from both crab species are conspecific but these also showed the geographical variations among them on both 28S and COI. The previous records of the genus Temnosewellia in East to South Asian countries are assembled and shown on the map (fig.7, this paper).

Diversity of European lissorchiid trematodes from fish and snail hosts with comments on the validity of the genus Parasymphylodora Szidat, 1943.

Genetic markers, DNA sequences and karyotypes, of some European lissorchiid species from their intermediate and final hosts were obtained to clarify controversial data about their life cycles and taxonomy, and to reveal phylogenetic affinities. The life cycles of three species have been confirmed for the first time based on molecular data. Comparative analysis of internal transcribed spacer 2 (ITS2) and partial 28S rDNA sequences has undoubtedly proven that cercariaeum of type-species of the genus Asymphylodora, Asymphylodora tincae, develops in pulmonate snails, Anisus vortex and Stagnicola palustris, but not in the genus Bithynia. The faucet snail, Bithynia tentaculata, serves as the first intermediate host for Parasymphylodora (=Asymphylodora) markewitschi and Parasymphylodora parasquamosa; adults of both species were isolated from the common rudd, Scardinius erythrophthalmus. It has also been confirmed that B. tentaculata serves as the second intermediate host for P. parasquamosa. Phylogenetic analysis supports the validity of the genus Parasymphylodora. Two species, Parasymphylodora markewitschi and P. parasquamosa, with cercariaeum belonging to the Parasquamosum group, are closely related and are being recovered as a well-defined evolutionary lineage in phylogenetic trees. A significant divergence between Parasymphylodora spp. and Asymphylodora spp. was revealed. The diploid chromosome set of P. markewitschi is composed of 14 chromosomes and does not show similarities with karyotypes of other lissorchiid species. Asymphylodora progenetica and Asymphylodora tincae share the basal diploid value of the family, 2n = 20, and reveal very close morphology of the corresponding chromosome pairs. Karyotypic similarities of these species are in accordance with molecular phylogenetic data. Thus, the available molecular and cytogenetic data support the assignment of P. markewitschi and P. parasquamosa to a separate genus, meanwhile, the assignment of A. progenetica to the genus Parasymphylodora was not justified.

Identification and Antimicrobial Activity of Actinobacteria Isolated from Rhizosphere of the Local Endemic Plants

The search for novel antimicrobial compounds from the environment has been gaining momentum with the increase in resistance of pathogens. In the present study, the antimicrobial potential of 11 local isolates of Actinobacteria which were isolated from rhizosphere soils of the three local endemic plants in Turkey was evaluated against different pathogenic bacteria and Candida albicans. Antimicrobial activity was investigated by the disk diffusion agar method using the organic extracts obtained from the isolates grown in the modified Bennett's medium and Tryptic Soy Broth (TSB). Eight isolates were revealed to show remarkable antimicrobial activity against to pathogens. Study of the production of bioactive metabolites in two different culture media indicated that the higher antimicrobial activity was observed in modified Bennett's medium when compared to TSB. Also, partial 16S rDNA sequence analyses revealed that 10 of these local isolates belong to member of Streptomyces and one of them to member Promicromonospora genera.

Gammarinema scyllae sp. n. and Monhystrium mangrovi sp. n. (Nematoda: Monhysteridae) from land crabs from New Caledonia

Two new species of nematodes associated with crabs are described from New Caledonia. Gammarinema scyllaesp. n. from the gill chambers of Scylla serrata (Forsskål) is characterised by 3–4 mm long body, small outer labial and cephalic sensilla, distinct ocelli, short straight spicules and sub-cylindrical tail. Monhystrium mangrovisp. n. from the gill chambers and body cavity of mangrove crab Neosarmatium sp. is characterised by 1–1.4 mm long body; outer labial sensilla longer than cephalic sensilla, amphid located at level with posterior stoma chamber, denticles in posterior stoma chamber and five pairs of genital papilla on tail. Phylogenetic relationships of two new species and other nematodes from the family Monhysteridae are analysed based on 18S and partial 28S rDNA sequences.

Urocleidoides spp. (Monogenea: Dactylogyridae) from the gills of Parodon nasus (Characiformes: Parodontidae) from a Brazilian stream with descriptions of two new species.

Urocleidoides spp. are reported from the gills of 20 specimens of Parodon nasus (standard length 8.512 cm), from the Indiana stream, Tiet River, Upper Paran River basin, municipality of Botucatu, So Paulo State, Brazil. Urocleoidoides tenuis and two new species were found. Urocleidoides indianensis n. sp. differs from its congeners mainly by the morphology of the vaginal sclerite that is robust, sickle-shaped, and forked at the distal end; and by the bulbous-shaped accessory piece of the male copulatory complex. Urocleidoides parodoni n. sp. resembles U. tenuis by presenting male copulatory organ with approximately 7 counterclockwise rings, but differs by the morphology of the accessory piece (lobate with a small hook-like projection versus pincer-shaped), vaginal sclerite (thumb-like subterminal projection vs. presence of a distal hook), vaginal tube (conspicuously sclerotized vs. slightly sclerotized), shape of the ventral bar (bowed vs. wide V-shaped), ventral and dorsal anchors (robust base and short shaft vs. considerably less robust base and long shaft), and hooks (slender shank with a weakly sclerotized subunit at base vs. dilated shank). Sequences of the partial 28S rDNA gene of the dactylogyrids found in this study are provided. Phylogenetic analyses showed Urocledoides spp. from Parodontidae clustering together with strong support values. This study increases the number of valid Urocleidoides species to 39, and the number of species described from parodontid hosts to four.

Oribatid mites (Acariformes, Sarcoptiformes: Oribatida) in the gills of Salmo spp. (Actinopterygii: Salmonidae) parr - Short communication.

Live oribatid mites of the family Malaconothridae were found on Salmo spp. parr caught in the rivers of Northwest Russia. The mites were localised in the gill filaments and enclosed in connective tissue capsules. The encapsulation was accompanied by hyperplasia and displacement of the respiratory epithelium. One mite specimen was an adult female, while all the other specimens were protonymphs. The adult female and one protonymph specimen were identified as Tyrphonothrus sp. Other protonymphs could be identified only at the family level. The obtained partial 18S rDNA sequence of one protonymph was 100% identical to that of Tyrphonothrus maior (NCBI accession No. KY922215). This is the first report of living malaconothrid mites encapsulated in fish gills, and the phenomenon may assume parasitic behaviour. However, the nature of the relationship between the mites and the fish requires further investigations.

Two new species of the marine flatworm Pericelis (Platyhelminthes: Polycladida) from southwestern Japan with an amendment of the generic diagnosis based on phylogenetic inference

ABSTRACT We describe two new polyclad species, Pericelis lactea sp. nov. and P. maculosa sp. nov., from Japan. Pericelis lactea sp. nov. is characterized by (i) a translucent white body, (ii) the male and female gonopores opening separately and (iii) a conical penis papilla. Pericelis maculosa sp. nov. is distinguished from its other congeners by (i) a translucent white body with white to light blue dots all over the dorsal surface and brown speckles around the pharyngeal area, (ii) the male and female gonopores opening separately and (iii) a long, cylindrical penis papilla. We also infer the phylogeny of 10 species of Diposthidae using a concatenated dataset comprising partial 18S and 28S rDNA sequences from the two new and eight other known species. Our results showed Marcusia alba Cuadrado, Rodríguez, Moro, Grande and Noreña, 2021 was nested within a clade comprising the seven Pericelis species included in the analysis. These findings support the prior synonymization of Marcusia with Pericelis based on the morphology, hence we transferred M. alba to Pericelis. We modified the diagnosis of Pericelis to accommodate such species as P. alba comb. nov. and P. lactea sp. nov., in which marginal eyespots are distributed only anteriorly. http://zoobank.org/urn:lsid:zoobank.org:pub:14906638-970B-4C67-81EE-E6111F98F77F

Expression of immune-related genes in parasite-infected Tilapia nilotica (Oreochromis niloticus) from Egypt and molecular characterization of the parasites

Aquaculture is one of the world's most rapidly developing animal production sectors. Tilapia nilotica (Oreochromis niloticus) is the most popular fish known for quality and price. In the present study sixty fish samples of Tilapia nilotica (Oreochromis niloticus) of about 16-22cm length were collected from Tilapia breeding farms and twenty Nile tilapia fish samples were collected for tissue sampling rom each farm. Fish samples were thoroughly investigated for external parasites by visual inspection microscopically through fixed wet smears from the gills and skin. The DNA was extracted from the fish and 17 different parasite species were amplified for partial 18S rDNA and entire ITS1 regions using three sets of commonly recommended primers. The amplicons were confirmed through sequencing. The results exhibited that Trichodina sp. and Gyrodactylus hildae in gills, Cichlidogyrus aegypticus on skin while Acanthosentis sp. was found in the intestine of infected tilapia within Fuwa City, Kafr El sheikh Governorate. The parasites found in Mataria City, Dakahlia Governorate were Cichidogyrus halli on the gills, Zschokkella candia on muscles, and Clinostomum tilapiae in the intestine. The parasites Dactylogyrus sp. and Myxobolus fomenai were recovered from the skin and muscles, respectively, of infected Tilapia from King Mariout, Borg El-Arab City, Alexandria Governorate. Moreover, the expression level of IL-1β gene was up-regulated in muscle, skin, gills and intestine tissues of fish infected with parasites such as Z. candia, C. halli, C. tilapiae, Dactylogyrus sp., M. fomenai, C. aegypticus, Trichodina sp., G. hildae, and Acanthocentis. The similar up-regulation tissues expression trends of TNF-α and IFN-γ genes were found in fish infested with these parasites. The present study exlored molecular characterization of different parasites isolated in different locations of Egypt in Tilapia nilotica (Oreochromis niloticus) and up-regulation of the inflammatory response genes such as IL-1β, TNF-α and IFN-γ is an indicator of the sever inflammation due to these parasitic infestation in fish.

First Report of Pseudomonas cichorii Causing Bacterial Leaf Spot on Romaine Lettuce (Lactuca sativa var. longifolia) and Escarole (Cichorium endivia) in New Jersey.

We previously reported an outbreak of bacterial leaf spot (BLS) caused by Pseudomonas cichorii occurring on sweet basil in New Jersey during the summer of 2018 (Patel et al. 2019), a growing season characterized by increased leaf wetness due to high humidity and unusually high levels of summer rains. Leaf spot was also observed, as a one-time event, on older mature leaves on romaine and escarole lettuce during that same year. Symptoms on escarole were observed as grayish brown-to-black concentric lesions on leaf parenchyma tissue, ranging from 1 mm to 1-2 cm in diameter. In more severely diseased samples, lesions coalesced to form larger necrotic areas giving a blight appearance. On occasion, infection was observed in leaf midveins as brownish gray necrosis. Symptoms on romaine lettuce were observed mostly as coalesced blackened lesions on leaf parenchyma tissue near margins with a rotted consistency that spread to the midvein in severe cases. Margins of leaf lesions were excised and macerated in sterile water before streaking onto Nutrient Agar (NA) and King's medium B agar (KMB) (Schaad et al. 2001). Growth on both NA and KMB were predominantly cream-colored circular bacterial colonies with undulated margins. Colonies on KMB fluoresced blue under 365nm UV light. Two representative colonies isolated from each host were selected for further characterization. All isolated tested negative for levan production, positive for oxidase, negative for potato rot, negative for arginine dihydrolase, and induced a strong hypersensitive response on tobacco within 24 h, consistent with LOPAT descriptions for P. cichorii (Lelliott et al. 1966). A single strain from each host (ESC6F2 and Rom1-1) was further characterized genetically to confirm species. PCR analysis using two primers sets: 16S rRNA gene universal primers 27F/1492R and Hcr1 primers used to amplify a 520 bp region of the pathogenicity gene cluster hrcRST in P. cichorii (Patel et al. 2019; Cottyn et al. 2011). Partial 16S rDNA gene sequences were deposited in the GenBank database for each isolate (ESC6F2: MT974180; and Rom1-1: MT982172). Sequence comparisons of ESC6F2 and Rom1-1 shared 99% identity with each other and several P. cichorii strains within the GenBank database, including strain B5-2-1 isolated from sweet basil in NJ the same year (MK501753). The partial hrcRST locus (strain ESC6F2: MW048775 and Rom1-1: MW048774) shared 100% identity to each other and strain B5-2-1 (MK507764), and 99% identity with P. cichorii strain P18-1 (MH396007) isolated from Ocimum basilicum in Hawaii. Koch's postulate was performed on escarole var. Full Heart and Romaine lettuce var. Ideal Cos to confirm pathogenicity of the isolated strains. Bacterial suspensions (1x107 cfu/ml) were syringe-injected (0.1 ml) into the leaf midribs, and pressure infiltrated into leaf parenchyma tissue of 3 plants. Control plants were inoculated with sterile water. Blackened necrosis developed within 72 h around bacteria-inoculation points, which expanded beyond inoculation points within a week. In contrast, control plants remained healthy and symptomless. Although significant crop loss occurred due to BLS on escarole and romaine lettuce, P. cichorii has not been isolated from diseased plant material since 2018. This suggests inoculum sources did not persist beyond 2018, or favorable environmental conditions for disease are inconsistent to cause noticeable damage to New Jersey crops.

Molecular identification of the rodent-borne pathogen Rodentolepis nana using the genetic markers of ITS-1, 18S, and 28S rDNA.

Rodentolepis nana (syn. Hymenolepis nana), the most common cyclophyllid tapeworm infecting rodents, is a well-studied gastrointestinal parasite in mice and belongs to the family Hymenolepididae. The present study focuses on the molecular analysis for the nuclear genes (ITS-1, 18S, and 28S rDNA) used for the accurate recognition of the recovered Rodentolepis species. The annotated partial ITS-1, 18S, and 28S rDNA gene regions were deposited in GenBank (gbǀ MW310394.1, gbǀ MW327585.1, and gbǀ MW324479.1, respectively) and further used in the maximum likelihood method (ML) to clarify their genetic relationships at the species level. The interrogation sequence of R. nana was aligned and belonged to the family Hymenolepididae, in the same group as all Hymenolepis species, which were distinct from Cyclophyllidea cestodes, especially species belonging to Anoplocephalidae and Taeniidae. Sequence data support the paraphyly of Hymenolepis species. The phylogeny supports the availability of the ITS-1, 18S, and 28S rDNA genes as reliable genetic markers for evolutionary relationships.

New species of the genus Spio (Annelida, Spionidae) from the southern and western coasts of Korea.

A new spionid polychaete, Spiopigmentatasp. nov., is described from the southern and western coasts of Korea. This new species differs from its congeners by the combination of the following morphological characteristics: the presence of orange-brown pigmentation on the anterior part of the prostomium, black pigmentation on the peristomium and along the body, U-shaped nuchal organs, a comparatively long extension of metameric dorsal ciliated organs, three pairs of white dots per chaetiger, two to three posterior abranchiate chaetigers, and the presence of tridentate neuropodial hooded hooks. The partial 16S ribosomal DNA (rDNA) and nuclear 18S rDNA sequences of the new species and Spio sp. 2 reported by Abe and Sato-Okoshi (2021) from Japan showed high similarity, indicating that these two specimens belong to the same species. A detailed description and illustrations of the new species, together with molecular information, are provided.

Morphological and molecular data of new species of Characithecium and Diaphorocleidus (Monogenea: Dactylogyridae) from Neotropical characid fishes.

The present study describes three new species of monogenean parasites of characid fishes from the Upper Paraná River basin, Brazil: Characithecium paranapanemense n. sp. on Psalidodon paranae and Psalidodon bockmanni, Diaphorocleidus magnus n. sp. on Astyanax lacustris and Psalidodon fasciatus, and Diaphorocleidus neotropicalis n. sp. on Astyanax lacustris and P. bockmanni. An amendment for Diaphorocleidus is proposed, since additional characters observed in the new species required to extend the generic diagnostic features mainly to include: articulation process connecting the base of the MCO with accessory piece present or absent, and accessory piece with variable shapes (plate-like, pincer-shaped, wrench-shaped, sheath-shaped), divided or not into subunits. Characithecium paranapanemense n. sp. can be distinguished from other congeners by the morphology of its MCO and accessory piece. Diaphorocleidus magnus n. sp. differs from most of its congeners by the morphology of its accessory piece, the presence of articulation process connecting the base of the MCO with accessory piece, and the morphology of the sclerotized structures of the haptor. Diaphorocleidus neotropicalis n. sp. can be easily distinguished from its congeners by the morphology of the accessory piece, the sclerotized structures of the haptor and the morphology of the vagina. Molecular data of the new species (partial 28S rDNA and mitochondrial cytochrome oxidase I) were obtained and the first phylogenetic analysis based on 28S rDNA gene sequences for species of Characithecium and Diaphorocleidus are provided. Although Diaphorocleidus and Characithecium share some morphological similarities, phylogenetic analysis indicates that species of these two genera are not closely related.

Ganga river water quality assessment using combined approaches: physico-chemical parameters and cyanobacterial toxicity detection with special reference to microcystins and molecular characterization of microcystin synthetase (mcy) genes carrying cyanobacteria.

Water quality assessment relies mostly on physico-chemical-based characterization; however, eutrophication and climate change advocate the abundance of toxic microcystins (MCs) producing cyanobacteria as emerging bio-indicator. In the present study, a spatial-temporal analysis was carried out at ten sampling sites of Prayagraj and Varanasi during June 2017 and March 2018 to determine the Ganga River water quality using physico-chemical parameters, cyanobacteria diversity, detection of MCs producing strains and MC-LR equivalence. Coliform bacteria, COD, NO3-N, and phosphate are the significant contaminated parameters favoring the growth of putative MCs producing cyanobacteria. National Sanitation Foundation WQI (NSFWQI) indicates water quality, either bad or medium category at sampling points. The morphological analysis confirms the occurrence of diverse cyanobacterial genera such as Microcystis, Anabaena, Oscillatoria, and Phormidium. PCR amplification affirmed the presence of toxic microcystin (mcy) genes in uncultured cyanobacteria at all the sampling sites. The concentration of MC-LR equivalence in water samples by protein phosphatase 1 inhibition assay (PPIA) and high-performance liquid chromatography (HPLC) methods was observed in the range of 23.4-172 ng/L and 13.2-97.5 ng/L respectively which is lower than the harmful exposure limit by World Health Organization (WHO). Ganga isolate 1 was identified as Microcystis based on partial 16S rDNA sequence and its toxicity was confirmed due to presence of mcy genes and MCs production potential. These findings suggest the presence of MCs producers as new emerging parameter to monitor water quality index and identification up to species level will be valuable for restoration strategies of river Ganga.

Production of the biosurfactant serrawettin W1 by Serratia marcescens S-1 improves hydrocarbon degradation.

With the frequent occurrence of oil spills, the bioremediation of petroleum hydrocarbons pollution has attracted more and more attention. In this study, we investigated the biodegradation of crude oil by the biosurfactant-producing strain S-1. The strain was isolated from petroleum-contaminated soil and identified as Serratia marcescens according to partial 16S rDNA gene analysis. It was able to effectively degrade hydrocarbons with the concomitant production of biosurfactants at 20-30°C, while there was no biosurfactant production and the degradation rate was lower at 37°C. The biosurfactant was identified as serrawettin W1 by UPLC-ESI-MS, and was found to reduce the surface tension of water to 30mN/m, with stable surface activity and emulsion activity at temperatures from 20 to 100°C, pH of 2-10 and NaCl concentrations of 0-50g/L. Serrawettin W1 significantly increased the cell surface hydrophobicity (CSH) and enhanced the bioavailability of hydrocarbon pollutants, which was conducive to the degradation of crude oil, including long-chain alkanes and aromatic hydrocarbons. Serratia marcescens S-1 has potential applications in bioremediation at low temperature.

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.

Morpho-molecular assessment of Acetabularia jalakanyakae Sp. Nov. (Dasycladales, Chlorophyta) - a new species from Andaman and Nicobar Islands, India

Acetabularia (Dasycladales) is an extant genus of a single-celled green alga. There are four species of this genus reported from India, three reported from Andaman and Nicobar Islands. For this study, Acetabularia isolate was collected from a rocky intertidal habitat in the Andaman and Nicobar Islands. Light microscopy and Scanning Electron Microscopy were used for the morphological characterization. The distinct traits of caps of the thalli were prioritized because, traditionally, species delimitations in Acetabularia mainly were based on cap morphology. Our isolate showed morphological similarity with Acetabularia crenulata. However, the number of hairs in the inner ring of lobes of caps and the stalk length were observed to be different from A. crenulata and other closely related species. The phylogenetic tree constructed for partial 18S rDNA using the Maximum Likelihood (ML) method revealed the evolutionary affinity of this new species with Acetabularia dentata. Based on morphological and molecular synapomorphy, a new species of Acetabularia, Acetabularia jalakanyakae is formally proposed herein, and the further implications of this species discovery are discussed.

Characterization of potassium solubilizing bacteria isolated from corn rhizoplane

Potassium is one of the most important elements in plant growth and development. Most of the potassium reserves on Earth are in insoluble mineral form, which represents a limitation for the absorption of this nutrient by plants. Some microorganisms can solubilize the mineral forms of potassium. This study aimed to isolate and identify potassium solubilizing bacteria resident in corn rhizoplane. To do this, bacteria that formed a solubilization halo around the colony on solid Aleksandrov culture medium were selected. These bacteria were then characterized considering the appearance of the colonies and cell morphology and were identified by partial 16S rDNA sequencing. Their solubilizing and potassium-releasing capacity was determined under different conditions of temperature, pH, and salinity, using potassium feldspar and muscovite as insoluble sources of potassium. Eight strains identified within the genera Paenibacillus, Lysinibacillus, Arthrobacter, Bacillus, Pseudomonas, and Stenotrophomonas were obtained. The release of potassium from feldspar was favored at 28 and 30°C, pH 7.5 and a saline concentration of 4 g L-1, while in the presence of muscovite the best conditions were 30 and 37°C, pH 5.5 and 7.5, and 4 g L-1 of NaCl. The most efficient strains were Bacillus sp. INCA-FRc7 and Bacillus sp. INCA-FRc19x with yields of up to 2.095 mg L-1. These strains could become alternatives to the use of potassium fertilizers and contribute to the ecological sanitation of the agroecosystems.

Morphological, histopathological and molecular characterization of Myxobolus szekelyianus n. sp. (Cnidaria: Myxosporea: Myxobolidae) causing acute gill disease in Schizothorax esocinus (Heckel, 1838) from River Jhelum of Kashmir Himalayan region, India

During the present study, we describe a novel myxozoan that forms plasmodia in the gill filament of Schizothorax esocinus collected from River Jhelum of Kashmir Himalayan region (n = 26). Description of the new species is based on morphology of the myxospore and on partial 18S rDNA gene. The results showed that the plasmodia were large, visible with naked eye, elongate in shape, whitish in colour, 8mm in diameter, at the centre of gill filament, histozoic, single or two in number per gill, but too big in size and filled by 1,000–1,400 myxospores. The myxospores measure 13.4 (length) × 9.5µm (width), short oval in frontal view, blunt at both in anterior and posterior, but somewhat narrowing towards the posterior end. Shell valves measure 0.45µm in thickness. No parietal folds were recorded. Two polar capsules equal in size, pyriform in shape were measured 7.3 × 4.2 µm (L × W). The 18S rDNA of this species (accession number MK785257) clustered phylogenetically with other related myxozoan parasites and showed maximum homogeneity of 98.63% with M. sp. SKBU-RC1 (MK412937) and M. sp. SKBU-RC2 (MK412937) infecting gills of Labeo rohita from India followed by 92.51% with M. pronini (MH329619) infecting abdominal cavity of Carassius gibelio from China. The study of histopathological changes of the gills revealed hypertrophy, hyperplasia, uplifting of cellular elements and severe damage to gill filaments resulting in suffocation of fish. By its unique myxospore morphology and its 18S rDNA sequence, we propose naming this species as Myxobolus szekelyianus n. sp.

The first case of Spiroxys contortus in European pond turtle (Emys orbicularis) in the wild in Poland.

During standard parasitological dissection of 4 individuals of European pond turtle (E. orbicularis) (Linneaus, 1758) one nematode was found. In a morphological examination the parasite was identified as Spiroxys contortus (Rudolphi, 1819) and confirmed by DNA analysis based on sequencing of the small subunit ribosomal RNA gene. The partial 18S rDNA gene was deposited to NCBI GenBank with the accession number MN629917. This is the first molecular evidence of S. contortus in E. orbicularis from wild from Poland. The analyzed sample genotype sequence shows 100% similarity to the reference specimen from Argentina.