Differential diagnosis of the genera in the family Trichodinidae (Ciliophora: Peritrichida) with the description of a new genus ectoparasitic on freshwater fish from southern Africa

A trichodinid ectoparasite was collected from mormyrid fish in the Olifants River System, South Africa. A new genus, Hemitrichodina, is described to accomodate these trichodinid ciliophorans of which the blades are reduced and with an adoral spiral of more than 360°, but less than two full turns. A differential diagnosis of the genera within the family Trichodinidae is presented.     

Trichodinids (Ciliophora: Peritrichia) from a calanoid copepod and catfish from South Africa with notes on host specificity

A case study is presented in which a trichodinid infestation was found on Clarias gariepinus (Burchell, 1822) larvae in a hatchery. Upon examination of copepods in the water system, it was found that they too hosted this trichodinid species. After following the infestation for some time it was found that the trichodinids on the catfish disappeared, whilst the infestation on the calanoid copepods persisted. It was concluded that the trichodinid originated from the copepods and could not establish a viable infestation on the catfish larvae. Specimens of catfish fry from the same farm, however, hosted a different trichodinid which is described as a new species. After analysis of published information, it was concluded that the trichodinid from these calanoid copepods belongs to the same species as described by different authors from various localities from Eurasia. In order to provide a specific identification of this trichodinid, a literature review is presented. In a discussion of host specificity, it is concluded that the trichodinid involved is specific to planktonic copepods and cannot establish an infestation on fish.     

Occurrence of Trichodina heterodentata (Ciliophora: Trichodinidae) infesting tadpoles of Rhinella pombali (Anura: Bufonidae) in the Neotropical area

Data on trichodinid ciliophorans in Brazil are scarce and generally do not use the modern silver-impregnation technique, which is essential to the taxonomy of the group. The present study reports not only on the first occurrence of Trichodina heterodentata in Brazil but also on the first record of this trichodinid infesting tadpoles of the species Rhinella pombali. This study also constitutes a second report on T. heterodentata from tadpoles. In September 2007, tadpoles were collected from a stream in a small farm in the agricultural area of the city of Juiz de Fora, southeastern Brazil. The ciliophorans found on the tadpoles' bodies and tails were submitted to techniques such as silver impregnation and scanning electron microscopy. Our biometric data of T. heterodentata population infesting Rhinella pombali were compared to five other South-African populations of T. heterodentata infesting tadpoles of Xenopus laevis laevis. Results were discussed in terms of low host specificity as well as the wide geographical distribution of this trichodinid.     

A new species of Trichodina (Ciliophora: Peritrichia) from the intestine of the surgeonfish Acanthurus xanthopterus

A population of a trichodinid (Ciliophora: Peritrichia) was found in the gut of the surgeonfish Acanthurus xanthopterus collected from Hawaii, South Africa and New Guinea and described as a new species. This is only the second record of a trichodinid from the intestine of a marine fish. In all the fish specimens examined, the micro-fauna normally found in other species of the fish family. Acanthuridae was absent and replaced entirely by the trichodinid population.     

A new species of <Emphasis Type="Italic">Trichodina</Emphasis> Ehrenberg, 1830 (Ciliophora: Trichodinidae) infecting farmed <Emphasis Type="Italic">Clarias gariepinus</Emphasis> (Burchell) (Siluriformes: Clariidae) in Cuba

A new species of Trichodina Ehrenberg, 1830 collected from the skin and fins of farmed North African catfish Clarias gariepinus (Burchell) fingerlings, is described. The new species can be distinguished from other trichodinids by the characteristics of the adhesive disc, especially by the great number of denticles. Trichodina merciae n. sp. is morphologically similar to T. renicola (Mueller, 1931) and T. marplatensis Martorelli, Marcotegui & Alda, 2008, in the number of denticles, but differs in the morphometric data, denticle morphology, environment and location. Trichodina merciae n. sp. has broad sickle-shaped blades and thin, straight rays, while T. marplatensis has broad club-shaped blades and wide S-shaped rays. Besides, denticle length, blade length, ray length, width of central part and denticle span of the new species are greater than T. marplatensis. However, the diameter of denticle ring and the diameter of the central area in T. marplatensis is larger than the ones in T. merciae n. sp. This is the first record of freshwater ectoparasite trichodinid with an average number of denticles greater than 50.     

Parasite fauna of seabass (Lates calcarifer) under mariculture conditions in Lampung Bay, Indonesia

Fish parasites have been repeatedly reported to be a major threat to the developing industry of finfish mariculture in Indonesia, due to severe parasite and disease outbreaks. The aim of this study was to identify the metazoan parasite fauna and trichodinid ciliates that infect Lates calcarifer in a representative mariculture farm in Indonesia. Examined were 105 L. calcarifer (seabass) for the metazoan parasite fauna and trichodinid ciliates. Thirty‐five specimens each from the net cages of the National Sea Farming Development Centre (Balai Budidaya Laut, BBL) in Lampung Bay, South Sumatra, Indonesia were investigated in three consecutive seasons (two dry and one rainy season from 2002 to 2003). Nineteen parasite species were identified; all fish specimens were infected with two to 10 parasite species, demonstrating a species‐rich parasite fauna. Protozoans (1 species), myxozoans (1), digeneans (3), monogeneans (5), cestodes (3), nematodes (5) and acanthocephalans (1) were found, including 11 new host records in cultured L. calcarifer from Indonesia. Larval and adult parasite stages were isolated, demonstrating that this fish species, although kept inside the net cages, still functions as an intermediate and final host for marine fish parasites. During all seasons, the six detected monoxenous (single host life cycle) parasite species showed a higher prevalence than the 13 heteroxenous (multiple hosts) species. Most abundant were the fish pathogenic monogeneans Pseudorhabdosynochus epinepheli, Pseudorhabdosynochus lantauensis, Benedenia epinepheli and Neobenedenia melleni with a high prevalence. Most heteroxenous parasites (Digenea, Cestoda, Nematoda and Acanthocephala) occurred with a low prevalence below 26%, caused by the specific culture conditions. Diversity of the heteroxenous parasites was higher in the dry seasons than in the rainy season. Though some seasonality could be observed for the fish pathogenic monogeneans, severe disease outbreaks of these ectoparasites cannot be excluded in either the dry or rainy season.     

Trichodinid (Ciliophora; Peritricha) gill parasites of freshwater fish in South Africa

Summary Trichodinella epizootica (Raabe, 1950) and seven new species of trichodinid ectoparasites (Ciliophora: Peritricha) were identified from both wild and pond fishes collected during an extensive survey of fish ponds, rivers and lakes in the Transvaal, South Africa. The new species are Tripartiella clavodonta n. sp., T. lechridens n. sp., T. leptospina, n. sp., T. macrosoma n. sp., T. nana n. sp., T. orthodens n. sp. and Trichodinella crennulata n. sp.     

大亚湾养殖鱼类寄生车轮虫的种类组成与季节动态

2017年8月至2018年7月对大亚湾8种养殖鱼类的车轮虫感染情况进行了调查, 采用Lom倡导的“统一特定方法”及Van As & Basson提出的“齿体定位描述法”对采获的车轮虫标本进行了形态鉴定与描述。结果在卵形鲳鲹(Trachinotus ovatus)、星点笛鲷(Lutjanus stellatus)、鞍带石斑鱼(Epinephelus lanceolatus)、眼斑拟石首鱼(Sciaenops ocellatus)和虎龙杂交斑[E. fuscoguttatus (♀) × E. lanceolatus (♂)]等5种鱼上共检获5种车轮虫: 亚卓车轮虫(Trichodina jadranica)、莱普斯车轮虫(T. lepsii)、长须鳠车轮虫(T. guliae)、劳牧小车轮虫(Trichodinella lomi)和斜拟车轮虫(Paratrichodina oblique); 其中卵形鲳鲹5种虫均有寄生, 虎龙杂交斑感染了4种虫, 星点笛鲷、眼斑拟石首鱼和鞍带石斑鱼分别感染了3种、2种和1种虫。周年感染数据表明: 5种虫的感染率均以卵形鲳鲹最高, 眼斑拟石首鱼上2种虫的感染率最低; 莱普斯车轮虫平均感染强度最高的宿主是虎龙杂交斑, 其他4种虫的均是卵形鲳鲹。寄生车轮虫的季节动态表明: 冬季的感染率和平均感染强度较低; 不同虫种感染高峰出现的季节不一, 其中斜拟车轮虫的感染高峰出现在秋季, 其春夏秋季的平均感染强度均大于其他4种虫。研究填补了大亚湾海区鱼类寄生车轮虫研究的空缺, 为该海区车轮虫病的诊断与防控提供了参考。     

矩形车轮虫的再描述

目的：我们对泸州市鲇类寄生车轮虫进行调查,对于已经发现,但由于原来的技术水限制需要重新描述的,或缺少资料的车轮虫,给予重新描述或补充新的资料。方法：用国际间统一的千银法染色以显示车轮虫的附着盘结构和口围绕度,用Lom（1958）倡导的”统一的特定方法”（Uniform specific characteristic system）进行测量,用Van＆Bassion（1989）提供的方法描述车轮虫的齿体。结果：对寄生在泸州地区养殖鱼类斑点叉尾鲴（Ietalums punetaus）的鳃上的车轮虫进行了描述,该车轮虫是矩形车轮虫（ Trichodina rectangli）。结论：矩形车轮虫是陈启鎏和谢杏人1964年在青鱼、草鱼等鱼身体上发现的,但是没有显微照片。国际上有许多它的同种异名的车轮虫的描述,这些文献也只有附着盘的显微照片。斑点叉尾鲡是矩形车轮虫的新寄主记录。本研究用国际统一的方法对矩形车轮虫进行描述,并绘出了矩形车轮虫的齿体定位图,提供了完整的统计数据,以及完整的显微照片,即附着盘、口围绕度和细胞核显微照片。     

Trichodina (Ciliata: Urceolariidae) of Freshwater Fishes of the Southeastern United States*

SYNOPSIS. Eight new species of Trichodina are described from freshwater fishes of the Southeastern U.S.: T. davisi from Roccus saxatilus (Walbaum), T. funduli from Fundulus notti (Agassiz), T. globosa from Etheostoma radiosum (Hubbs and Black), T. hoffmani from Etheostoma edwini (Hubbs and Cannon), T. hypsilepis from Notropis hypsilepis Suttkus and Raney, T. microdenticula from Dorosoma petenense (Gunther). T. noturi from Noturus leptacanthus Jordan, and T. salmincola from Salmo gairdneri Richardson. Nine species of Trichodina are redescribed: T. californica, T. discoidea, T. fultoni, T. pediculus, T. platyformis, T. reticulata, T. sp. (?T. nigra), T. tumefaciens, and T. vallata. The name T. pediculus is re-erected for the form that occurs on largemouth bass. Host fish were collected from 36 geographic locations in 10 states (Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, and Tennessee). A total of 939 fish of 46 species was examined for trichodinid parasites. Two methods of impregnating formalin preserved specimens of Trichodina with silver are discussed. A key to the species of Trichodina reported from North American freshwater fishes is given.     

Trichodinid Protozoa (Ciliophora: Peritrichida) from Freshwater Fishes of Rybinsk Reservoir,USSR1

During the spring of 1981, trichodinid protozoa were collected from the gills or urinary bladder of the following species of fishes of Rybinsk Reservoir, USSR, located on the upper reaches of the Volga River system: Esox lucius, Rutilus rutilus, Leuciscus idus, Blicca bjoerkna, Abramis ballerus, Pelecus cultratus, Lota lota, and Perca fluviatilis. A total of 13 species of Trichodinidae was recovered from Rybinsk fishes, among which are three new species of the genus Trichodina: T. izyumovae n. sp. from the gills of L. idus, T. borokensis n. sp. from the gills of P. cultratus, and T. kupermani n. sp. from the gills of A. ballerus. Other species of trichodinids reported are T. modesta Lom, 1980; T. nigra Lom, 1969; T. pediculus (O. F. Müller, 1786); T. prowazeki Grupcheva & Lom, 1980; T. rostrata Kulemina, 1968; T. urinaria Dogiel, 1940; T. ophiocephalus Kostenko & Karaev, 1976; Paratrichodina incisa (Lom, 1959); Trichodinella epizootica (Raabe, 1950); and Tripartiella copiosa Lom, 1959. Photomicrographs and morphometric data are presented for each species and aspects of their host and geographic distribution discussed. Trichodina algonquinensis Li & Desser, 1983 is considered a synonym of T. urinaria Dogiel, 1940.     

Trichodinidae in commercial fish in South America

Ciliates of the family Trichodinidae are protozoan parasites of importance for fish farming in South America, given that at high infestation levels, they cause significant mortality among farmed fish. Although data on economic losses due to parasitosis are not available for South America, mortality outbreaks correlated to trichodinids are very common in the tilapia production chain, especially in Brazil, the largest aquaculture chain in the country. In Brazil in the past, trichodinids were considered only as Trichodina sp. Today, they have been better studied and identified taxonomically in wild and farmed fish. However, in other countries in South America, trichodinids continue to be described only as Trichodina sp. This review presents the history of occurrences of trichodinids in fish of interest in South America, highlighting 15 new species that have been described in three genera in Brazil, along with information on parasite-host-environment relationships, diagnostic methods and treatments. The occurrence of parasitic ciliates must be correlated with farming conditions such as stress factors, water quality, seasonality, age and host immunity to elucidate the critical points of each production system. Furthermore, for tropical fish, studies on treatment against trichodinid species are needed to provide support for approval of antiparasitic medications for use in fish farming. However, it is recommended that the production sector use intensive production systems that are more sustainable, with biosafety protocols, to increase production and productivity.     

Hyperparasitism of trichodinid ciliates on monogenean gill flukes of two marine fish

Two unusual cases of hyperparasitism of trichodinid ciliates on monogenean gill flukes are described from southern Israel (Red Sea). The first case occurred in cultured European sea bass Dicentrarchus labrax infected by Diplectanum aequans, while the second was observed in a feral devil firefish Pterois miles infected by Haliotrema sp. In both cases, the trichodinids heavily co-infested the host fish gills. The flukes were completely coated by the ciliates, which gave them a cobblestone appearance, but no damage to their tegument was apparent. Both cases are most likely a result of accidental hyperparasitism, brought about by perturbed environmental conditions.     

The salinity tolerance of trichodinids (Protozoa) parasitic on the Three-spined stickleback Gasterosteus aculeatus

Sticklebacks from a variety of habitats have been examined for trichodinids. Two species of trichodinid were found on fish at every site. They were identified as Trichodina domerguei subsp. domerguei and T. tenuidens , and these identifications are discussed in relation to previous observations by other workers. The tolerance to change in salinity has been examined for both species and the activity of the contractile vacuole of T. domerguei has been examined in detail.     

Trichodinid ectoparasites (Ciliophora: Peritrichida) of some River Nile fish, Egypt

Four species of trichodinid ectoparasites (Ciliophora: Peritrichida) were collected from the gills of the following River Nile fish in Egypt: Hydrocynus forskalii, Mormyrus kannume, Schilbe mystus. These species are: Trichodina heterodentata Duncan, 1977, Trichodina fahaka sp. n., Trichodinella epizootica Raabe, 1950, Tripartiella dactylodentata sp. n. Photomicrographs and morphometric data are presented for each species.     

Deletion of the GRE3 Aldose Reductase Gene and Its Influence on Xylose Metabolism in Recombinant Strains of Saccharomyces cerevisiae Expressing the xylA and XKS1 Genes

Saccharomyces cerevisiae ferments hexoses efficiently but is unable to ferment xylose. When the bacterial enzyme xylose isomerase (XI) from Thermus thermophilus was produced in S. cerevisiae, xylose utilization and ethanol formation were demonstrated. In addition, xylitol and acetate were formed. An unspecific aldose reductase (AR) capable of reducing xylose to xylitol has been identified in S. cerevisiae. The GRE3 gene, encoding the AR enzyme, was deleted in S. cerevisiae CEN.PK2-1C, yielding YUSM1009a. XI from T. thermophilus was produced, and endogenous xylulokinase from S. cerevisiae was overproduced in S. cerevisiae CEN.PK2-1C and YUSM1009a. In recombinant strains from which the GRE3 gene was deleted, xylitol formation decreased twofold. Deletion of the GRE3 gene combined with expression of the xylA gene from T. thermophilus on a replicative plasmid generated recombinant xylose utilizing S. cerevisiae strain TMB3102, which produced ethanol from xylose with a yield of 0.28 mmol of C from ethanol/mmol of C from xylose. None of the recombinant strains grew on xylose.     

Prevalence of Streptococcus suis Genotypes in Wild Boars of Northwestern Germany

Invasive serotype 2 (cps2⁺) strains of Streptococcus suis cause meningitis in pigs and humans. Four case reports of S. suis meningitis in hunters suggest transmission of S. suis through the butchering of wild boars. Therefore, the objective of this study was to investigate the prevalence of potentially human-pathogenic S. suis strains in wild boars. S. suis was isolated from 92% of all tested tonsils (n = 200) from wild boars. A total of 244 S. suis isolates were genotyped using PCR assays for the detection of serotype-specific genes, the hemolysin gene sly, and the virulence-associated genes mrp and epf. The prevalence of the cps2⁺ genotype among strains from wild boars was comparable to that of control strains from domestic pig carriers. Ninety-five percent of the cps2⁺ wild boar strains were positive for mrp, sly, and epf*, the large variant of epf. Interestingly, epf* was significantly more frequently detected in cps2⁺ strains from wild boars than in those from domestic pigs; epf* is also typically found in European S. suis isolates from humans, including a meningitis isolate from a German hunter. These results suggest that at least 10% of wild boars in Northwestern Germany carry S. suis strains that are potentially virulent in humans. Additional amplified fragment length polymorphism analysis supported this hypothesis, since homogeneous clustering of the epf* mrp⁺ sly⁺ cps2⁺ strains from wild boars with invasive human and porcine strains was observed.     

Preparation of chlorophyll a, chlorophyll b and bacteriochlorophyll a by means of column chromatography with diethylaminoethylcellulose

Chlorophyll a, chlorophyll b and bacteriochlorophyll a were prepared by means of column chromatography with Sephadex LH-20 and diethylaminoethylcellulose. This method provides purified preparations of chlorophylls in about 3 h.To prepare chlorophyll a, blue-green or red algae were used as the starting material. Chlorophyll a was extracted with 90% aqueous acetone from cells of blue-green algae, Anabaena variabilis, Anacystis nidulans and Tolypothrix tenuis, and with 90% aqueous methanol from thalli of a red alga, Porphyra yezoensis. Chlorophyll a was collected as precipitates by adding dioxane and water to the extract according to the method of Iriyama et al. [6]. The crude chlorophyll a preparation was applied to a Sephadex LH-20 column with chloroform as the eluent and then to a DEAE-cellulose column with a chloroform/methanol mixture (49 : 1, v/v) as the eluent. Analysis with thin layer chromatography revealed that the chlorophyll a preparation contained no detectable contaminants.Bacteriochlorophyll a was prepared in a similar manner from purple photosynthetic bacteria, Rhodopseudomonas spheroides and Chromatium vinosum.In order to prepare chlorophyll b, chloroplasts of spinach leaves were used as the starting material. A mixture of chlorophylls a and b was obtained in the same way as described for the preparation of chlorophyll a from the blue-green algae. To separate chlorophyll b from chlorophyll a, the mixture was applied to a diethylaminoethylcellulose column which was developed with a hexane/2-propanol mixture (5 : 2, v/v).     

Aerosols as a Source of Widespread Mycoplasma Contamination of Tissue Cultures

Mycoplasma isolates were cultured from 15 antibiotic-free cell cultures obtained from a single laboratory. Complement-fixation tests showed that these isolates were antigenically related to each other but were unrelated to M. hominis type 1, M. hominis type 2, M. arthritidis, M. laidlawii type B, Mycoplasma sp. H.Ep. #2 (Barile), or M. salivarium. Examination of serum used to feed the infected cell lines revealed no Mycoplasma. Infection resulting from cross-contamination by a single Mycoplasma strain from one cell culture to another was investigated. Although the organisms were not found in the air over the work area, aerosols containing these contaminants were produced in tissue culture bottles during the trypsinization of cell monolayers. The minimal infectious dose of Mycoplasma for tissue cultures was measured, and it was determined that one organism was capable of initiating an infection in a tissue culture. The pattern of contamination and the small dose required for infection indicated that Mycoplasma contamination was spread from one tissue culture to another via aerosols. It was demonstrated that Mycoplasma can be transferred from one cell culture to another through the use of a common burette for dispensing medium.