Genomic resources for Platyhelminthes of the class Monogenea are scarce, despite the diversity of... more Genomic resources for Platyhelminthes of the class Monogenea are scarce, despite the diversity of these parasites, some species of which are highly pathogenic to their fish hosts. This work aimed to generate de novo-assembled transcriptomes of two monogenean species, Scutogyrus longicornis (Dactylogyridae) and Rhabdosynochus viridisi (Diplectanidae), providing a protocol for cDNA library preparation with low input samples used in single cell transcriptomics. This allowed us to work with sub-microgram amounts of total RNA with success. These transcriptomes consist of 25,696 and 47,187 putative proteins, respectively, which were further annotated according to the Swiss-Prot, Pfam, GO, KEGG, and COG databases. The completeness values of these transcriptomes evaluated with BUSCO against Metazoa databases were 54.1% and 73%, respectively, which is in the range of other monogenean species. Among the annotations, a large number of terms related to G-protein-coupled receptors (GPCRs) were found. We identified 109 GPCR-like sequences in R. viridisi, and 102 in S. longicornis, including family members specific for Platyhelminthes. Rhodopsin was the largest family according to GRAFS classification. Two putative melatonin receptors found in S. longicornis represent the first record of this group of proteins in parasitic Platyhelminthes. Forty GPCRs of R. viridisi and 32 of S. longicornis that were absent in Vertebrata might be potential drug targets. The present study provides the first publicly available transcriptomes for monogeneans of the subclass Monopisthocotylea, which can serve as useful genomic datasets for functional genomic research of this important group of parasites.
Fish–parasite systems could be subject to two scenarios under climate change: (i) increased water... more Fish–parasite systems could be subject to two scenarios under climate change: (i) increased water temperature might enhance parasite metabolism, allowing the parasite to spread rapidly; (ii) parasitism could decrease if the optimal temperature for growth and transmission is exceeded. Sea lice are parasitic copepods commonly found on marine fish in tropical regions, yet their biology remains poorly investigated. In this study, we analyzed the changes in infection levels and the transcriptomic response of the tropical sea louse Caligus confusus to two seasonal seawater temperatures (30 °C, “warm”, and 21 °C, “cold”). The prevalence of C. confusus was significantly higher in the colder water. A de novo transcriptomic analysis of C. confusus, the first for a tropical sea louse, revealed 426 over-expressed and 1402 down-expressed transcripts at the lower temperature. In particular, we observed over-expression of transcripts encoding vitellogenins (vit-1, vit-2, vit-4, and vit-6) and matr...
A new multivalvulid myxosporean species, Kudoa dianae sp. n., is described from bullseye puffer, ... more A new multivalvulid myxosporean species, Kudoa dianae sp. n., is described from bullseye puffer, Sphoeroides annulatus (Jenyns) (Tetraodontiformes: Tetraodontidae). Plasmodia develop in extramuscular sites, in the wall of oesophagus and less frequently on mesenteries. Mature spores can reach lumen of the digestive tract directly by disruption of plasmodial wall or via macrophage transport to the oesophageal epithelium. New species is characterised by morphology of spores and by the complete sequence of SSU rRNA gene that differs from all hitherto known sequences of Kudoa species. Spore morphology (moderate-sized, simple non-ornate spores, quadrate in apical view) clusters with that of Kudoa scienae, K. cerebralis, K. chilkaensis, K. leiostomi, K. funduli, K. cascasia and K. ovivora. Analysis of phylogenetic relationships (using SSU rRNA gene sequences) among five Kudoa species, the molecular data of which are available thus far, revealed that K. dianae is distinguishable from these five species and that its closest relation is with K. miniauriculata.
Heterobothrium ecuadori is a gil monogenean infecting the gils of the bullseye puffer fish Sphoer... more Heterobothrium ecuadori is a gil monogenean infecting the gils of the bullseye puffer fish Sphoeroides annulatus and feeding fish blood. すれisexperimental study was performed to describe the juvenile stages of H. ecuadori and to determine the time required to reach the adult stage at 20-230C. Uninfected bullseye puffer fish were exposed to oncomiracidia and sampled at intervals to obtain worms of different developmental stages. Between 5 and 10 days after the exposure, the first and second pairs of clamps were observed in worms along with the emergence of the third clamp. Four pairs of clamps were observed on day 15, and prト mordial male copulatory organ, testes and ovary were found on day 20. Adult parasites started to appear between 25 and 30 days post幽 infection. The time required for egg laying was estimated to be 33 days, based on the first collection of eggs in the rearing water.
Molecular genetics and genomics : MGG, Jan 20, 2014
We performed de novo transcriptome sequencing for Panax ginseng and Panax quinquefolius accession... more We performed de novo transcriptome sequencing for Panax ginseng and Panax quinquefolius accessions using the 454 GS FLX Titanium System and discovered annotation-based genome-wide single-nucleotide polymorphism (SNPs) using next-generation ginseng transcriptome data without reference genome sequence. The comprehensive transcriptome characterization with the mature roots of four ginseng accessions generated 297,170 reads for 'Cheonryang' cultivar, 305,673 reads for 'Yunpoong' cultivar, 311,861 reads for the G03080 breeding line, and 308,313 reads for P. quinquefolius. In transcriptome assembly, the lengths of the sample read were 156.42 Mb for 'Cheonryang', 161.95 Mb for 'Yunpoong', 165.07 Mb for G03080 breeding line, and 166.48 Mb for P. quinquefolius. A total of 97 primer pairs were designed with the homozygous SNP presented in all four accessions. SNP genotyping using high-resolution melting (HRM) analysis was performed to validate the putative SNP ...
The present study is the first description of the egg morphology, embryonic development, and time... more The present study is the first description of the egg morphology, embryonic development, and time required for hatching, and longevity of the oncomiracidium of Heterobothrium ecuadori (Meserve, 1938) Sproston, 1946. Experiments found that hatching time fluctuated between 7 and 10 days with a mean of 7.5 ± 1 days at 23 ± 1° C and 35 ‰. Eggs were provided with a polar filamentous appendage. The body of the oncomiracidium was flattened dorso-ventrally, 156 ± 9 μm long and 65 ± 8 μm wide. A full description of the egg development and morphology of the oncomiracidium is provided. The longevity of the oncomiracidia was 4–7 days at 21 ± 1°C, with a mean survival time of 121.8h. The ability to rear diclidophorids like H. ecuadori and to record precise information on their development provides valuable data for further studies.
Las granjas pequeñas de tilapia contribuyen al desarrollo rural sostenible; sin embargo, los pará... more Las granjas pequeñas de tilapia contribuyen al desarrollo rural sostenible; sin embargo, los parásitos pueden afectar su productividad. El presente estudio determinó la prevalencia e intensidad de tricodínidos y monogéneos en granjas de tilapia de Guerrero, Oaxaca y Chiapas. Se identificaron seis especies de tricodínidos: Trichodina centrostrigeata, T. compacta, T. heterodentata, T. magna, T. nigra y Trichodina sp.; y nueve de monogéneos: Cichlidogyrus cirratus, C. dossoui, C. halli, C. mbirizei, C. sclerosus, C. thurstonae, C. tilapiae, Gyrodactylus cichlidarum y Scutogyrus longicornis. Los registros de C. mbirizei y C. cirratus son nuevos para México. Los tricodínidos y monogéneos se presentaron, respectivamente, en 73 y 93 % de las granjas muestreadas, tanto en regiones montañosas, valles o costa. La prevalencia de tricodínidos fue alta (60–100 %) en 30 % de las granjas, pero la intensidad mediana fue menor a 10 parásitos/pez. La prevalencia de monogéneos fue alta en la mayoría d...
The effective formalin therapeutic concentration (ETC) against Cichlidogyrus spp. infecting tilap... more The effective formalin therapeutic concentration (ETC) against Cichlidogyrus spp. infecting tilapia was obtained. Also, the stress and immune response to formalin baths in O. niloticus were achieved. A static bioassay with four concentrations (0.5, 1.0, 1.5, 2.0 mL L-1) of formaldehyde (37% dilution) in water, and one control without this substance was performed. Results evidenced that 1.5 mL L-1 of formalin for 40 min was the ETC to eradicate monogeneans without manifesting macroscopic damage to fishes. Thirty tilapias underexposure with ETC of formalin (FORM Group) were evaluated for stress, utilizing cortisol and glucose determination, and immune response (lysozyme activity and differential counting of organic defense cells). Other 30 tilapias without cichlidogyriasis and with no exposure to formalin were the Control Group. Evaluation times were: three hour pre-treatment (T0), and one hour, three days and three months post-treatment (T1, T2, and T3, respectively). A peak of cortisol (~326 ng mL-1) was observed in tilapias of FORM Group at T1 with significant differences with the control group (P ˂ 0.05). Similarly, glucose concentration reached significant values (~119 mg dL-1) at one hour after the conclusion of treatment (P ˂ 0.05). Those values returned to the basal limit at the last time of the study. The lysozyme activity and white blood cells in differential counting showed no significant differences in the same conditions (P > 0.05). Results confirmed total control of cichlidogyriasis with the ETC of formalin obtained and an evident resistance of tilapia to treatment as stabilization of its physiological stress response was achieved.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 2008
Nine bacterial strains were studied by means of rep-PCR, 16S rRNA gene sequence analysis, DNA-DNA... more Nine bacterial strains were studied by means of rep-PCR, 16S rRNA gene sequence analysis, DNA-DNA hybridization and physiological characterization. Typing analysis by means of rep-PCR showed that all nine strains were highly homogeneous, with similarities above 94 %. The strains were isolated from the same geographical area (Mazatlá n, Sinaloa state, Mexico) and the same type of host (cultured rose snapper, Lutjanus guttatus), although from different individuals and organs. Comparison of the almost-complete 16S rRNA gene sequences of five strains showed that they belonged to the genus Vibrio and are closely related to the type strains of Vibrio brasiliensis and Vibrio hepatarius, with similarity values ranging from 97.9 to 98.1 % and from 97.4 to 97.8 %, respectively. The DNA-DNA hybridization value of strain CAIM 797 T with the type strain of V. brasiliensis (CAIM 495 T) was 47.5 %, with a reciprocal value of 44.7 %. The main phenotypic features of the strains were in agreement with the phylogenetic and genomic data. The results presented here support the description of a novel species, for which the name Vibrio sinaloensis sp. nov. is proposed, with strain CAIM 797 T (5CECT 7298 T) as the type strain.
Parasitic copepods of the family Caligidae, the so-called sea lice, may be deleterious to marine ... more Parasitic copepods of the family Caligidae, the so-called sea lice, may be deleterious to marine or brackish finfish aquaculture. To date, biological and ecological studies of sea lice have been mostly restricted to species from cold or temperate regions. In Mexico there are some records of sea lice species on marine fishes; however, the research regarding their biology and ecology has been scarce. It is possible that a high biodiversity of sea lice is distributed in coastal waters of Mexico; therefore, their significance as pathogenic parasites should increase. The purpose of this review is to outline the current knowledge of the life cycle, host location, ecology, effect on fish health, and control strategies of sea lice in order to establish supportive basis for natural resource management and control of parasites and diseases of marine fish cultured in Mexico.
Thalassas: an International Journal of Marine Sciences, Mar 3, 2022
The purpose of this study was to provide a comprehensive updated list of published and unpublishe... more The purpose of this study was to provide a comprehensive updated list of published and unpublished records of monogeneans, digeneans, cestodes, acanthocephalans, and nematodes parasitizing snappers (Lutjanidae) in the Caribbean (CAR), Gulf of Mexico (GOM), and Mexican Pacific (MP). We incorporated data from bibliographic research, as well as new data derived from a fish health survey performed by the Fish and Wildlife Research Institute in the northern GOM. The number of helminth taxa in snappers from CAR, GOM, and MP was 171 (80 digeneans, 27 monogeneans, 11 cestodes, 11 acanthocephalans, and 42 nematodes) from 26 host species. The digeneans Stephanostomum casum, Hamacreadium mutabile, Helicometrina nimia, and Siphodera vinaledwardsii, the monogenean Euryhaliotrema tubocirrus, and nematode larvae of Cucullanidae and Philometridae families were the most commonly reported helminths. Lutjanus griseus hosted the highest number (72) of helminth species. This information provides a reference for future parasitological studies.
RESUMEN. Los copepodos parasitos de la familia Caligidae, comunmente llamados ³piojos de mar´, so... more RESUMEN. Los copepodos parasitos de la familia Caligidae, comunmente llamados ³piojos de mar´, son descritos como uno de los problemas mas serios que afectan a la industria del salmon en la etapa de engorda en el mar a nivel mundial, causando lesiones en la piel, crecimiento lento y mortalidad. Gran parte de los conocimientos biologicos y ecologicos de estos organismos se han obtenido a partir de especies de aguas frias o templadas. En Mexico, el conocimiento de este grupo de parasitos se ha limitado a registros esporadicos de especies nuevas o ya conocidas, pero poco se sabe sobre su biologia y ecologia. La diversidad de caligidos en peces silvestres puede ser alta en las costas mexicanas, por lo que no deberia descartarse su potencial riesgo sanitario en areas de interes para la piscicultura marina. En este articulo se resume el conocimiento actual sobre el ciclo de vida, localizacion de hospedero, ecologia, efecto en la salud de los peces y metodos de control de caligidos. Mejora...
We report the nearly complete mitochondrial genome of Rhabdosynochus viridisi – the first for thi... more We report the nearly complete mitochondrial genome of Rhabdosynochus viridisi – the first for this genus – achieved by combining shotgun sequencing of genomic and cDNA libraries prepared using low-input protocols. This integration of genomic information leads us to correct the annotation of the gene features. The mitochondrial genome consists of 13,863 bp. Annotation resulted in the identification of 12 protein-encoding genes, 22 tRNA genes and two rRNA genes. Three non-coding regions, delimited by three tRNAs, were found between the genes nad5 and cox3. A phylogenetic analysis grouped R. viridisi with three other species of diplectanid monogeneans for which mitochondrial genomes are available.
Ciliate ectoparasites are one of the most important groups of pathogens in fish culture, and the ... more Ciliate ectoparasites are one of the most important groups of pathogens in fish culture, and the traditional treatments are sometimes harmful to the fish and the environment. Thus, the search for novel compounds that are effective at low concentrations and safe for fish are necessary to optimise treatments in aquaculture. The antiprotozoal capacity of silver nanoparticles (AgNPs) against the ciliate Tetrahymena has been documented; however, their toxicity may vary with the synthesis methodology and nanoparticle size. The objectives of this study were a) to evaluate the acute toxicity in vitro of two AgNPs (Argovit™ and UTSA) on Tetrahymena sp., a biological model for ciliated ectoparasites of fish and b) to test the safety of lethal and higher doses of UTSA AgNPs for ciliates on the fish C. estor. Light microscopy and scanning electron microscopy (SEM) were used to determine whether AgNPs affected the structure of the cell surface of Tetrahymena. The mortality, histopathological alterations and metagenomics of the fish were used to determine the major effects of UTSA AgNPs. In Tetrahymena, the median lethal concentration (LC 50) for Argovit™ was 2501 ± 1717 ng/L at 15 min and 796 ± 510 ng/L at 60 min, while the LC 50 for UTSA AgNPs was 4 ± 2 and 1 ± 0.6 ng/L at 15 min and 60 min, respectively. A concentration of 3300 ng/L Argovit™ and 10.6 ng/L UTSA AgNPs for 15 and 60 min, respectively, was 100% effective against Tetrahymena. After 60 min of exposure to 0.25 and 0.50 ng/L UTSA AgNPs, the number of cilia significantly reduced, there were small holes on the cell surface, and the cellular membrane was ruptured. In fish exposed to lethal (10.6 ng/L) and higher (31.8 and 95.4 ng/L) doses of UTSA, the AgNPs did not affect fish survival after 96 h, and there were no signs of histopathological damage or gut microbial changes. This study is the first report on microscopic and ultrastructural changes in Tetrahymena after exposure to significantly low concentrations of UTSA AgNPs with antiprotozoal efficacy without evidence of harmful effects on fish. These results provide the basis for further studies of both pet aquarium and commercial fish that may validate these findings at a larger experimental scale, taking into account AgNPs bioaccumulation, safety for human consumption and environmental impact.
En este trabajo se presenta un panorama general del impacto de los parásitos en el cultivo de til... more En este trabajo se presenta un panorama general del impacto de los parásitos en el cultivo de tilapia. Se describen algunas estrategias, incluyendo la aplicación de tratamientos naturales como una alternativa a los agentes químicos o fármacos, que deberían considerarse para la prevención de eventos epidémicos. Sin duda, los desarrollos biotecnológicos que garanticen la prevención y control de enfermedades, sin poner en riesgo la salud humana o del ecosistema, deberían prevalecer en la acuicultura de la tilapia.
Diclidophoridae and Capsalidae are families of monogenean parasites that include some of the most... more Diclidophoridae and Capsalidae are families of monogenean parasites that include some of the most pathogenic species for cultured finfish. In this study, the efficacy of praziquantel (PZQ) and a combination anthelmintic (PZQ, ivermectin, pyrantel pamoate and fenbendazole) commercialized under the name of Adecto® (Adler Pharma) were evaluated in vitro against adults and eggs of the diclidophorid Tagia ecuadori and the capsalid Neobenedenia melleni. Freshwater and formalin immersions were also evaluated against T. ecuadori for comparative purposes. In addition, the efficacy in vivo of Adecto® as a bath treatment to eliminate mixed infections as well as the median lethal concentration (LC 50) of this drug in juvenile, healthy bullseye puffer fish (Sphoeroides annulatus) were determined. Triglycerides, hemoglobin, total protein and glucose levels were measured in three groups of fish: uninfected, infected and infected/treated with Adecto®. At the doses tested, PZQ did not have a concentration-dependent effect. Thus, 2.5 mg/L PZQ was 100% effective against adults of T. ecuadori after 20 h, and 3 mg/L killed 87% of N. melleni after 12 h. Adecto® had a concentration-dependent effect. The concentration required to kill all parasites in the minimum time was 20 mg/L Adecto® (12 h for T. ecuadori, and 16 h for N. melleni). Neither PZQ nor Adecto® were effective at inhibiting egg hatching. Adults of T. ecuadori were highly tolerant to freshwater; mortality was < 40% after 24 h, whereas formalin was 100% effective against both adults and eggs in this species. In vivo, 20 mg/L Adecto® administered for 12 h was 100% effective against T. ecuadori; however, it was not 100% effective against N. melleni. Mixed infections provoked increases in hemoglobin and total protein levels in fish. Fish exposed to 20 mg/L Adecto® did not show signs of toxic effect after 24 h. For those fish, the 24-h LC 50 of Adecto® was 30.8 mg/L. This study confirms that PZQ is effective against the parasitic phase of monogeneans but under prolonged exposure. Our results suggest that combination anthelmintics have the potential to kill all parasites in less time; however, alternative combinations should be investigated to find one that is effective under low concentrations to provide a greater safety margin.
Genomic resources for Platyhelminthes of the class Monogenea are scarce, despite the diversity of... more Genomic resources for Platyhelminthes of the class Monogenea are scarce, despite the diversity of these parasites, some species of which are highly pathogenic to their fish hosts. This work aimed to generate de novo-assembled transcriptomes of two monogenean species, Scutogyrus longicornis (Dactylogyridae) and Rhabdosynochus viridisi (Diplectanidae), providing a protocol for cDNA library preparation with low input samples used in single cell transcriptomics. This allowed us to work with sub-microgram amounts of total RNA with success. These transcriptomes consist of 25,696 and 47,187 putative proteins, respectively, which were further annotated according to the Swiss-Prot, Pfam, GO, KEGG, and COG databases. The completeness values of these transcriptomes evaluated with BUSCO against Metazoa databases were 54.1% and 73%, respectively, which is in the range of other monogenean species. Among the annotations, a large number of terms related to G-protein-coupled receptors (GPCRs) were found. We identified 109 GPCR-like sequences in R. viridisi, and 102 in S. longicornis, including family members specific for Platyhelminthes. Rhodopsin was the largest family according to GRAFS classification. Two putative melatonin receptors found in S. longicornis represent the first record of this group of proteins in parasitic Platyhelminthes. Forty GPCRs of R. viridisi and 32 of S. longicornis that were absent in Vertebrata might be potential drug targets. The present study provides the first publicly available transcriptomes for monogeneans of the subclass Monopisthocotylea, which can serve as useful genomic datasets for functional genomic research of this important group of parasites.
Fish–parasite systems could be subject to two scenarios under climate change: (i) increased water... more Fish–parasite systems could be subject to two scenarios under climate change: (i) increased water temperature might enhance parasite metabolism, allowing the parasite to spread rapidly; (ii) parasitism could decrease if the optimal temperature for growth and transmission is exceeded. Sea lice are parasitic copepods commonly found on marine fish in tropical regions, yet their biology remains poorly investigated. In this study, we analyzed the changes in infection levels and the transcriptomic response of the tropical sea louse Caligus confusus to two seasonal seawater temperatures (30 °C, “warm”, and 21 °C, “cold”). The prevalence of C. confusus was significantly higher in the colder water. A de novo transcriptomic analysis of C. confusus, the first for a tropical sea louse, revealed 426 over-expressed and 1402 down-expressed transcripts at the lower temperature. In particular, we observed over-expression of transcripts encoding vitellogenins (vit-1, vit-2, vit-4, and vit-6) and matr...
A new multivalvulid myxosporean species, Kudoa dianae sp. n., is described from bullseye puffer, ... more A new multivalvulid myxosporean species, Kudoa dianae sp. n., is described from bullseye puffer, Sphoeroides annulatus (Jenyns) (Tetraodontiformes: Tetraodontidae). Plasmodia develop in extramuscular sites, in the wall of oesophagus and less frequently on mesenteries. Mature spores can reach lumen of the digestive tract directly by disruption of plasmodial wall or via macrophage transport to the oesophageal epithelium. New species is characterised by morphology of spores and by the complete sequence of SSU rRNA gene that differs from all hitherto known sequences of Kudoa species. Spore morphology (moderate-sized, simple non-ornate spores, quadrate in apical view) clusters with that of Kudoa scienae, K. cerebralis, K. chilkaensis, K. leiostomi, K. funduli, K. cascasia and K. ovivora. Analysis of phylogenetic relationships (using SSU rRNA gene sequences) among five Kudoa species, the molecular data of which are available thus far, revealed that K. dianae is distinguishable from these five species and that its closest relation is with K. miniauriculata.
Heterobothrium ecuadori is a gil monogenean infecting the gils of the bullseye puffer fish Sphoer... more Heterobothrium ecuadori is a gil monogenean infecting the gils of the bullseye puffer fish Sphoeroides annulatus and feeding fish blood. すれisexperimental study was performed to describe the juvenile stages of H. ecuadori and to determine the time required to reach the adult stage at 20-230C. Uninfected bullseye puffer fish were exposed to oncomiracidia and sampled at intervals to obtain worms of different developmental stages. Between 5 and 10 days after the exposure, the first and second pairs of clamps were observed in worms along with the emergence of the third clamp. Four pairs of clamps were observed on day 15, and prト mordial male copulatory organ, testes and ovary were found on day 20. Adult parasites started to appear between 25 and 30 days post幽 infection. The time required for egg laying was estimated to be 33 days, based on the first collection of eggs in the rearing water.
Molecular genetics and genomics : MGG, Jan 20, 2014
We performed de novo transcriptome sequencing for Panax ginseng and Panax quinquefolius accession... more We performed de novo transcriptome sequencing for Panax ginseng and Panax quinquefolius accessions using the 454 GS FLX Titanium System and discovered annotation-based genome-wide single-nucleotide polymorphism (SNPs) using next-generation ginseng transcriptome data without reference genome sequence. The comprehensive transcriptome characterization with the mature roots of four ginseng accessions generated 297,170 reads for 'Cheonryang' cultivar, 305,673 reads for 'Yunpoong' cultivar, 311,861 reads for the G03080 breeding line, and 308,313 reads for P. quinquefolius. In transcriptome assembly, the lengths of the sample read were 156.42 Mb for 'Cheonryang', 161.95 Mb for 'Yunpoong', 165.07 Mb for G03080 breeding line, and 166.48 Mb for P. quinquefolius. A total of 97 primer pairs were designed with the homozygous SNP presented in all four accessions. SNP genotyping using high-resolution melting (HRM) analysis was performed to validate the putative SNP ...
The present study is the first description of the egg morphology, embryonic development, and time... more The present study is the first description of the egg morphology, embryonic development, and time required for hatching, and longevity of the oncomiracidium of Heterobothrium ecuadori (Meserve, 1938) Sproston, 1946. Experiments found that hatching time fluctuated between 7 and 10 days with a mean of 7.5 ± 1 days at 23 ± 1° C and 35 ‰. Eggs were provided with a polar filamentous appendage. The body of the oncomiracidium was flattened dorso-ventrally, 156 ± 9 μm long and 65 ± 8 μm wide. A full description of the egg development and morphology of the oncomiracidium is provided. The longevity of the oncomiracidia was 4–7 days at 21 ± 1°C, with a mean survival time of 121.8h. The ability to rear diclidophorids like H. ecuadori and to record precise information on their development provides valuable data for further studies.
Las granjas pequeñas de tilapia contribuyen al desarrollo rural sostenible; sin embargo, los pará... more Las granjas pequeñas de tilapia contribuyen al desarrollo rural sostenible; sin embargo, los parásitos pueden afectar su productividad. El presente estudio determinó la prevalencia e intensidad de tricodínidos y monogéneos en granjas de tilapia de Guerrero, Oaxaca y Chiapas. Se identificaron seis especies de tricodínidos: Trichodina centrostrigeata, T. compacta, T. heterodentata, T. magna, T. nigra y Trichodina sp.; y nueve de monogéneos: Cichlidogyrus cirratus, C. dossoui, C. halli, C. mbirizei, C. sclerosus, C. thurstonae, C. tilapiae, Gyrodactylus cichlidarum y Scutogyrus longicornis. Los registros de C. mbirizei y C. cirratus son nuevos para México. Los tricodínidos y monogéneos se presentaron, respectivamente, en 73 y 93 % de las granjas muestreadas, tanto en regiones montañosas, valles o costa. La prevalencia de tricodínidos fue alta (60–100 %) en 30 % de las granjas, pero la intensidad mediana fue menor a 10 parásitos/pez. La prevalencia de monogéneos fue alta en la mayoría d...
The effective formalin therapeutic concentration (ETC) against Cichlidogyrus spp. infecting tilap... more The effective formalin therapeutic concentration (ETC) against Cichlidogyrus spp. infecting tilapia was obtained. Also, the stress and immune response to formalin baths in O. niloticus were achieved. A static bioassay with four concentrations (0.5, 1.0, 1.5, 2.0 mL L-1) of formaldehyde (37% dilution) in water, and one control without this substance was performed. Results evidenced that 1.5 mL L-1 of formalin for 40 min was the ETC to eradicate monogeneans without manifesting macroscopic damage to fishes. Thirty tilapias underexposure with ETC of formalin (FORM Group) were evaluated for stress, utilizing cortisol and glucose determination, and immune response (lysozyme activity and differential counting of organic defense cells). Other 30 tilapias without cichlidogyriasis and with no exposure to formalin were the Control Group. Evaluation times were: three hour pre-treatment (T0), and one hour, three days and three months post-treatment (T1, T2, and T3, respectively). A peak of cortisol (~326 ng mL-1) was observed in tilapias of FORM Group at T1 with significant differences with the control group (P ˂ 0.05). Similarly, glucose concentration reached significant values (~119 mg dL-1) at one hour after the conclusion of treatment (P ˂ 0.05). Those values returned to the basal limit at the last time of the study. The lysozyme activity and white blood cells in differential counting showed no significant differences in the same conditions (P > 0.05). Results confirmed total control of cichlidogyriasis with the ETC of formalin obtained and an evident resistance of tilapia to treatment as stabilization of its physiological stress response was achieved.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 2008
Nine bacterial strains were studied by means of rep-PCR, 16S rRNA gene sequence analysis, DNA-DNA... more Nine bacterial strains were studied by means of rep-PCR, 16S rRNA gene sequence analysis, DNA-DNA hybridization and physiological characterization. Typing analysis by means of rep-PCR showed that all nine strains were highly homogeneous, with similarities above 94 %. The strains were isolated from the same geographical area (Mazatlá n, Sinaloa state, Mexico) and the same type of host (cultured rose snapper, Lutjanus guttatus), although from different individuals and organs. Comparison of the almost-complete 16S rRNA gene sequences of five strains showed that they belonged to the genus Vibrio and are closely related to the type strains of Vibrio brasiliensis and Vibrio hepatarius, with similarity values ranging from 97.9 to 98.1 % and from 97.4 to 97.8 %, respectively. The DNA-DNA hybridization value of strain CAIM 797 T with the type strain of V. brasiliensis (CAIM 495 T) was 47.5 %, with a reciprocal value of 44.7 %. The main phenotypic features of the strains were in agreement with the phylogenetic and genomic data. The results presented here support the description of a novel species, for which the name Vibrio sinaloensis sp. nov. is proposed, with strain CAIM 797 T (5CECT 7298 T) as the type strain.
Parasitic copepods of the family Caligidae, the so-called sea lice, may be deleterious to marine ... more Parasitic copepods of the family Caligidae, the so-called sea lice, may be deleterious to marine or brackish finfish aquaculture. To date, biological and ecological studies of sea lice have been mostly restricted to species from cold or temperate regions. In Mexico there are some records of sea lice species on marine fishes; however, the research regarding their biology and ecology has been scarce. It is possible that a high biodiversity of sea lice is distributed in coastal waters of Mexico; therefore, their significance as pathogenic parasites should increase. The purpose of this review is to outline the current knowledge of the life cycle, host location, ecology, effect on fish health, and control strategies of sea lice in order to establish supportive basis for natural resource management and control of parasites and diseases of marine fish cultured in Mexico.
Thalassas: an International Journal of Marine Sciences, Mar 3, 2022
The purpose of this study was to provide a comprehensive updated list of published and unpublishe... more The purpose of this study was to provide a comprehensive updated list of published and unpublished records of monogeneans, digeneans, cestodes, acanthocephalans, and nematodes parasitizing snappers (Lutjanidae) in the Caribbean (CAR), Gulf of Mexico (GOM), and Mexican Pacific (MP). We incorporated data from bibliographic research, as well as new data derived from a fish health survey performed by the Fish and Wildlife Research Institute in the northern GOM. The number of helminth taxa in snappers from CAR, GOM, and MP was 171 (80 digeneans, 27 monogeneans, 11 cestodes, 11 acanthocephalans, and 42 nematodes) from 26 host species. The digeneans Stephanostomum casum, Hamacreadium mutabile, Helicometrina nimia, and Siphodera vinaledwardsii, the monogenean Euryhaliotrema tubocirrus, and nematode larvae of Cucullanidae and Philometridae families were the most commonly reported helminths. Lutjanus griseus hosted the highest number (72) of helminth species. This information provides a reference for future parasitological studies.
RESUMEN. Los copepodos parasitos de la familia Caligidae, comunmente llamados ³piojos de mar´, so... more RESUMEN. Los copepodos parasitos de la familia Caligidae, comunmente llamados ³piojos de mar´, son descritos como uno de los problemas mas serios que afectan a la industria del salmon en la etapa de engorda en el mar a nivel mundial, causando lesiones en la piel, crecimiento lento y mortalidad. Gran parte de los conocimientos biologicos y ecologicos de estos organismos se han obtenido a partir de especies de aguas frias o templadas. En Mexico, el conocimiento de este grupo de parasitos se ha limitado a registros esporadicos de especies nuevas o ya conocidas, pero poco se sabe sobre su biologia y ecologia. La diversidad de caligidos en peces silvestres puede ser alta en las costas mexicanas, por lo que no deberia descartarse su potencial riesgo sanitario en areas de interes para la piscicultura marina. En este articulo se resume el conocimiento actual sobre el ciclo de vida, localizacion de hospedero, ecologia, efecto en la salud de los peces y metodos de control de caligidos. Mejora...
We report the nearly complete mitochondrial genome of Rhabdosynochus viridisi – the first for thi... more We report the nearly complete mitochondrial genome of Rhabdosynochus viridisi – the first for this genus – achieved by combining shotgun sequencing of genomic and cDNA libraries prepared using low-input protocols. This integration of genomic information leads us to correct the annotation of the gene features. The mitochondrial genome consists of 13,863 bp. Annotation resulted in the identification of 12 protein-encoding genes, 22 tRNA genes and two rRNA genes. Three non-coding regions, delimited by three tRNAs, were found between the genes nad5 and cox3. A phylogenetic analysis grouped R. viridisi with three other species of diplectanid monogeneans for which mitochondrial genomes are available.
Ciliate ectoparasites are one of the most important groups of pathogens in fish culture, and the ... more Ciliate ectoparasites are one of the most important groups of pathogens in fish culture, and the traditional treatments are sometimes harmful to the fish and the environment. Thus, the search for novel compounds that are effective at low concentrations and safe for fish are necessary to optimise treatments in aquaculture. The antiprotozoal capacity of silver nanoparticles (AgNPs) against the ciliate Tetrahymena has been documented; however, their toxicity may vary with the synthesis methodology and nanoparticle size. The objectives of this study were a) to evaluate the acute toxicity in vitro of two AgNPs (Argovit™ and UTSA) on Tetrahymena sp., a biological model for ciliated ectoparasites of fish and b) to test the safety of lethal and higher doses of UTSA AgNPs for ciliates on the fish C. estor. Light microscopy and scanning electron microscopy (SEM) were used to determine whether AgNPs affected the structure of the cell surface of Tetrahymena. The mortality, histopathological alterations and metagenomics of the fish were used to determine the major effects of UTSA AgNPs. In Tetrahymena, the median lethal concentration (LC 50) for Argovit™ was 2501 ± 1717 ng/L at 15 min and 796 ± 510 ng/L at 60 min, while the LC 50 for UTSA AgNPs was 4 ± 2 and 1 ± 0.6 ng/L at 15 min and 60 min, respectively. A concentration of 3300 ng/L Argovit™ and 10.6 ng/L UTSA AgNPs for 15 and 60 min, respectively, was 100% effective against Tetrahymena. After 60 min of exposure to 0.25 and 0.50 ng/L UTSA AgNPs, the number of cilia significantly reduced, there were small holes on the cell surface, and the cellular membrane was ruptured. In fish exposed to lethal (10.6 ng/L) and higher (31.8 and 95.4 ng/L) doses of UTSA, the AgNPs did not affect fish survival after 96 h, and there were no signs of histopathological damage or gut microbial changes. This study is the first report on microscopic and ultrastructural changes in Tetrahymena after exposure to significantly low concentrations of UTSA AgNPs with antiprotozoal efficacy without evidence of harmful effects on fish. These results provide the basis for further studies of both pet aquarium and commercial fish that may validate these findings at a larger experimental scale, taking into account AgNPs bioaccumulation, safety for human consumption and environmental impact.
En este trabajo se presenta un panorama general del impacto de los parásitos en el cultivo de til... more En este trabajo se presenta un panorama general del impacto de los parásitos en el cultivo de tilapia. Se describen algunas estrategias, incluyendo la aplicación de tratamientos naturales como una alternativa a los agentes químicos o fármacos, que deberían considerarse para la prevención de eventos epidémicos. Sin duda, los desarrollos biotecnológicos que garanticen la prevención y control de enfermedades, sin poner en riesgo la salud humana o del ecosistema, deberían prevalecer en la acuicultura de la tilapia.
Diclidophoridae and Capsalidae are families of monogenean parasites that include some of the most... more Diclidophoridae and Capsalidae are families of monogenean parasites that include some of the most pathogenic species for cultured finfish. In this study, the efficacy of praziquantel (PZQ) and a combination anthelmintic (PZQ, ivermectin, pyrantel pamoate and fenbendazole) commercialized under the name of Adecto® (Adler Pharma) were evaluated in vitro against adults and eggs of the diclidophorid Tagia ecuadori and the capsalid Neobenedenia melleni. Freshwater and formalin immersions were also evaluated against T. ecuadori for comparative purposes. In addition, the efficacy in vivo of Adecto® as a bath treatment to eliminate mixed infections as well as the median lethal concentration (LC 50) of this drug in juvenile, healthy bullseye puffer fish (Sphoeroides annulatus) were determined. Triglycerides, hemoglobin, total protein and glucose levels were measured in three groups of fish: uninfected, infected and infected/treated with Adecto®. At the doses tested, PZQ did not have a concentration-dependent effect. Thus, 2.5 mg/L PZQ was 100% effective against adults of T. ecuadori after 20 h, and 3 mg/L killed 87% of N. melleni after 12 h. Adecto® had a concentration-dependent effect. The concentration required to kill all parasites in the minimum time was 20 mg/L Adecto® (12 h for T. ecuadori, and 16 h for N. melleni). Neither PZQ nor Adecto® were effective at inhibiting egg hatching. Adults of T. ecuadori were highly tolerant to freshwater; mortality was < 40% after 24 h, whereas formalin was 100% effective against both adults and eggs in this species. In vivo, 20 mg/L Adecto® administered for 12 h was 100% effective against T. ecuadori; however, it was not 100% effective against N. melleni. Mixed infections provoked increases in hemoglobin and total protein levels in fish. Fish exposed to 20 mg/L Adecto® did not show signs of toxic effect after 24 h. For those fish, the 24-h LC 50 of Adecto® was 30.8 mg/L. This study confirms that PZQ is effective against the parasitic phase of monogeneans but under prolonged exposure. Our results suggest that combination anthelmintics have the potential to kill all parasites in less time; however, alternative combinations should be investigated to find one that is effective under low concentrations to provide a greater safety margin.
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Papers by Emma J Fajer