RESUMEN
Acanthocephalans are a group of obligate endoparasites that alternate between vertebrates and invertebrates to complete their life cycles. Occasionally, the same individual host acts as a definitive or paratenic host for different acanthocephalan species. In this study, acanthocephalans were sampled in marine fish in three localities of the Yucatán Peninsula; adults and cystacanths were recovered from the intestine and body cavity, respectively, of Haemulon plumierii from off the coast of Sisal, Yucatán. Ribosomal DNA sequences (small and large subunits) were used to test the phylogenetic position of the species of the genus Dollfusentis, whereas the mtDNA gene cox 1 was used for assessing species delimitation. The cox 1 analysis revealed an independent genetic lineage, which is recognized herein as a new species, Dollfusentis mayae n. sp. The new species is morphologically distinguished from the other six congeners by having a cylindrical proboscis armed with 22-25 longitudinal rows bearing 12 hooks each. The cystacanths were morphologically identified as Gorgorhynchus medius by having a cylindrical trunk covered with tiny irregular spines on the anterior region, and a cylindrical proboscis armed with 17-18 longitudinal rows of 21 hooks each; small and large subunit phylogenetic analyses yielded G. medius within the family Isthomosacanthidae, suggesting that Gorgorhynchus should be transferred to this family from Rhadinorhynchidae where it is currently allocated.
Asunto(s)
Acantocéfalos , Helmintiasis Animal , Perciformes , Animales , México , Filogenia , Helmintiasis Animal/parasitología , Peces/parasitología , Perciformes/parasitologíaRESUMEN
BACKGROUND: The results of clinical and weaning readiness tests and the spontaneous breathing trial (SBT) are used to predict the success of the weaning process and extubation. METHODS: We evaluated the capacity of the cuff leak test, rate of rapid and shallow breathing, cough intensity, and diaphragmatic contraction velocity (DCV) to predict the success of the SBT and extubation in a prospective, multicenter observational study with consecutive adult patients admitted to four intensive care units. We used receiver operating characteristic (ROC) curves to assess the tests' predictive capacity and built predictive models using logistic regression. RESULTS: We recruited 367 subjects who were receiving invasive mechanical ventilation and on whom 456 SBTs were performed, with a success rate of 76.5%. To predict the success of the SBT, we derived the following equation: (0.56 × Cough) - (0.13 × DCV) + 0.25. When the cutoff point was ≥ 0.83, the sensitivity was 91.5%, the specificity was 22.1%, and the overall accuracy was 76.2%. The area under the ROC curve (AUC-ROC) was 0.63. To predict extubation success, we derived the following equation: (5.7 × SBT) + (0.75 × Cough) - (0.25 × DCV) - 4.5. When the cutoff point was ≥ 1.25, the sensitivity was 96.8%, the specificity was 78.4%, and the overall accuracy was 91.5%. The AUC-ROC of this model was 0.91. CONCLUSION: Objective measurement of cough and diaphragmatic contraction velocity could be used to predict SBT success. The equation for predicting successful extubation, which includes SBT, cough, and diaphragmatic contraction velocity values, showed excellent discriminative capacity.
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Extubación Traqueal , Tos , Adulto , Humanos , Tos/diagnóstico , Estudios Prospectivos , Valor Predictivo de las Pruebas , Desconexión del Ventilador/métodos , Respiración Artificial/métodosRESUMEN
Polymorphidae is a monophyletic group of acanthocephalans distributed worldwide. Within this family, Hexaglandula corynosoma is a specialist species that uses a single bird species as a definitive host. Southwellina hispida is a generalist species that uses a broad spectrum of definitive hosts to complete its life cycle. In the current research, sequences of cytochrome c oxidase subunit 1 (cox1) from mitochondrial DNA were generated from 44 specimens of H. corynosoma and 76 of S. hispida distributed sympatrically in 6 biogeographic provinces of Mexico with the objective of characterizing and comparing the population genetic structure of 2 acanthocephalan species with opposing life strategies. The phylogeographic studies indicated that the populations of both species lacked a phylogeographic structure and exhibited high haplotype diversity, low nucleotide diversity and low Fst values among the biogeographic provinces; in combination with negative values on the neutrality test, this suggests that the populations of acanthocephalans are expanding. Paratenic hosts are key for the transmission from intermediate to definitive hosts in the generalist species. However, the inclusion of paratenic hosts does not play a principal role in the population genetic structure of S. hispida within its distribution along the coasts of Mexico.
RESUMEN
Childhood intimate partner violence (IPV) exposure increases the likelihood of internalizing and externalizing problems. There is substantial variability in children's outcomes following IPV exposure, but the reasons behind this are unclear, particularly among preschool-age children. The current study aimed to examine the direct and indirect effects of IPV on preschoolers' mental health through parent factors (parenting and parental depression), exploring child temperament as a potential moderator of the relation between IPV and child outcomes. Participants were 186 children (85 girls) and their parents living in the United States. Data were initially collected when children were age three, with follow-up at ages four and six. Both parents' baseline IPV perpetration had adverse effects on child outcomes. Mothers' IPV was associated with greater paternal depression, paternal overractivity, and maternal laxness, whereas fathers' IPV was associated with more paternal overreactivity. Only paternal depression mediated the effect of mothers' IPV on child outcomes. Parenting did not mediate nor did child temperament moderate the relation between IPV and child outcomes. Results shed insight into the need to address parental mental health in families experiencing IPV and underline the need for a further exploration of individual- and family-level mechanisms of adjustment following IPV exposure.
RESUMEN
The acanthocephalan Macracanthorhynchus ingens (von Linstow 1879) (Acanthocephala: Archiacanthocephala) is a parasite that infects the gut of carnivores (racoons, coyotes, wolves, foxes, badgers, skunks, opossum, mink and bears) as an adult and the body cavity of lizards, snakes, and frogs as a cystacanth in the Americas. In this study, adults and cystacanths of M. ingens from southeastern Mexico and southern Florida, USA, were identified morphologically by having a cylindrical proboscis armed with 6 rows of hooks each with 6 hooks. Hologenophores were used to sequence the small (SSU) and large (LSU) subunits of ribosomal DNA and cytochrome c oxidase subunit 1 (cox 1) from mitochondrial DNA. Phylogenetic analysis of the new SSU and LSU sequences of M. ingens placed them in a clade with other sequences available in GenBank identified as M. ingens. The cox 1 tree showed that the nine new sequences and six previously published sequences of M. ingens from the USA form a clade with other sequences previously identified as M. ingens from GenBank. The intraspecific genetic divergence among isolates from the Americas ranged from 0 to 2%, and in combination with the phylogenetic trees confirmed that the isolates belonged to the same species. The cox 1 haplotype network inferred with 15 sequences revealed 10 haplotypes separated from each other by a few substitutions. Rio Grande Leopard Frogs and Vaillant´s Frogs harbored cystacanths with low prevalence, 28% and 37% respectively, in Mexico. Brown Basilisks, an invasive lizard in Florida, USA, had high values of prevalence, 92% and 93% in males and females, respectively. Females harbored more cystacanths than males (0-39 vs 0-21) for unknown reasons that may, however, be related to ecological differences.
Asunto(s)
Acantocéfalos , Helmintiasis Animal , Femenino , Masculino , Animales , México , Filogenia , Helmintiasis Animal/epidemiología , Helmintiasis Animal/parasitología , Especificidad de la EspecieRESUMEN
Members of the genus Microphallus Ward, 1901, are endoparasites mainly of birds and mammals distributed worldwide. Unencysted metacercariae of Microphallus sp., were collected from the mesoglea of ctenophores of the genus Pleurobrachia Fleming; adult digeneans were recovered from the intestines of Eudocimus albus Linnaeus (Threskiornithidae) and Buteogallus urubitinga Gmelin (Accipitridae), in four locations from southeastern Mexico. Adult specimens were identified as M. basodactylophallus (Bridgman, 1969) based on the following features: body pyriform entirely covered by minute spines, prepharynx short, oesophagus very long, caeca short and widely divergent, testes slightly symmetrical and excretory vesicle short and V-shaped. Sequences from D1-D3 domain of the large subunit of ribosomal DNA (LSU) were generated, aligned, and compared with those of congeneric species available in GenBank. Phylogenetic analyses indicated that the metacercariae and adults formed a clade together with an isolate identified as M. basodactylophallus from Florida, USA (GenBank: AY220628). The intraspecific genetic divergence among isolates was low ranged from 0.0% to 0.6%, allowing the link between the two stages of the life cycle. We observed phenotypic plasticity in the morphological traits of M. basodactylophallus adults in definitive hosts (mammals and birds) throughout the distribution, which ranged from the USA to southeastern Mexico. Finally, the unencysted metacercariae identified as M. basodactylophallus represent the first report of a microphallid in ctenophores.
Asunto(s)
Aves , Ctenóforos , Parásitos , Trematodos , Animales , Aves/parasitología , Larva , Metacercarias/genética , México , Filogenia , Especificidad de la Especie , Trematodos/genéticaRESUMEN
This commentary focuses on the remunerated work dimension of productive aging in Mexico, specifically paid employment. The main purpose is to draw attention to productive aging policies and programs built on alliances between the Mexican government and private companies - e.g., Starbucks - and then to analyze the potential impacts of such alliances on the older population. We argue that although the Mexican government emphasizes the rights of older adults to engage in paid-employment programs through such alliances, it is not addressing the issues that underlie paid-employment activities in later life, such as conditions of inequality, lack of opportunities, and poverty. We also argue that the instrumentation of productive aging programs implemented by the government should consider the costs and benefits for older adults. Solid, research-based evidence is needed to better implement productive aging programs by accounting for the factors that influence older adults' decisions to continue working, the functional capacities of older workers, and their performance needs.
Asunto(s)
Envejecimiento , Sector Privado , Humanos , Anciano , México , Empleo , GobiernoRESUMEN
PURPOSE: To determine risk factors (RFs) for hemorrhagic adverse events (AEs) associated with percutaneous transhepatic biliary drainage (PTBD) and to develop a risk assessment model. MATERIALS AND METHODS: This was a multicenter, prospective, case control study between 2015 and 2020. Adults with an indication for PTBD were included. Patients who had undergone recent previous drainage procedures were excluded. Multiple variables were controlled. The exposure variables were the number of capsular punctures and passes (using the same puncture). A multivariate analysis was performed (logistic regression analysis). RESULTS: A total of 304 patients (mean age, 63 years ± 14 [range, 23-87 years]; female, 53.5%) were included. Hemorrhagic AEs occurred in 13.5% (n = 41) of the patients, and 3.0% (n = 9) of the cases were severe. Univariate analysis showed that the following variables were not associated with hemorrhagic AEs: age, sex, bilirubin and hemoglobin levels, type of pathology, portal hypertension, location of vascular punctures, ascites, nondilated bile duct, intrahepatic tumors, catheter features, blood pressure, antiplatelet drug use, and tract embolization. Multivariate analysis showed that number of punctures (odds ratio [OR], 2.5; P = .055), vascular punctures (OR, 4.1; P = .007), fatty liver or cirrhosis (OR, 3.7; P = .021), and intrahepatic tumor obstruction (Bismuth ≥ 2; OR, 2.4; P = .064) were associated with hemorrhagic AEs. Patients with corrected coagulopathies had fewer hemorrhagic AEs (OR, -5.5; P = .026). The predictability was 88.2%. The area under the curve was 0.56 (95% confidence interval, 0.50-0.61). CONCLUSIONS: Preprocedural and intraprocedural RFs were identified in relation to hemorrhage with PTBD. AE risk assessment information may be valuable for prediction and management of hemorrhagic AEs.
Asunto(s)
Drenaje , Hemorragia , Adulto , Estudios de Casos y Controles , Drenaje/efectos adversos , Drenaje/métodos , Femenino , Hemorragia/etiología , Humanos , Persona de Mediana Edad , Estudios Prospectivos , Estudios Retrospectivos , Factores de RiesgoRESUMEN
Trematode taxonomy is mainly based on the morphological traits of adults. The identification of metacercariae is challenging because such traits are not developed in larval forms, and they even may show some level of morphological variability. Studies testing the potential correspondence between morphological differences and genetic variation of parasites are still lacking. The metacercariae of Posthodiplostomum minimum are probably the diplostomids more widely distributed in North and Middle American freshwater fish, and their intraspecific morphological variability has been attributed to the effect exerted by the host. Here, we tested the hypothesis whether they represent a single species, or a species complex by assessing the genetic divergence and phylogenetic relationships of metacercariae sampled from several host species in a wide geographical range across Middle America. The internal transcribed spacers (ITS1-5.8S-ITS2), and the mitochondrial COI gene were sequenced for 124 and 55 metacercariae, respectively. Phylogenetic analysis inferred from ITS sequences uncovered six well-supported monophyletic lineages. The six lineages show no correspondence to any Posthodiplostomum species for which sequences are available thus far in GenBank. Lineages exhibit some degree of host specificity; Lineages I, II, IV and V are primarily parasites of cyprinodontiforms of the families Poeciliidae, Goodeidae, Profundulidae and Fundulidae. In poeciliids there are at least four candidate species of Posthodiplostomum, some of them occurring in sympatry; instead, Lineages II and VI are exclusively parasites of cichlids. This study contributes to our understanding of the diversity of larval forms of diplostomids and provides an opportunity to further study their life cycles.
Asunto(s)
Enfermedades de los Peces , Trematodos , Infecciones por Trematodos , Animales , Enfermedades de los Peces/parasitología , Peces/parasitología , Agua Dulce , Variación Genética , Humanos , Metacercarias/anatomía & histología , Filogenia , Infecciones por Trematodos/parasitología , Infecciones por Trematodos/veterinariaRESUMEN
Patagifer Dietz, 1909 is a small genus of echinostomatids, with 12 recognized species, mostly parasitising threskiornithid birds, distributed worldwide. In the current research, adult specimens of the type species, Patagifer bilobus (Rudolphi, 1819) Dietz, 1909 from the white faced ibis (Plegadis chihi) and white ibis (Eudocimus albus) were re-described, providing new metrical data for the number of head collar spines. Those specimens were recorded from eight localities in Mexico and compared morphologically with specimens previously identified as Patagifer lamothei. A total of 19 specimens identified as P. bilobus including two hologenophores were sequenced with three molecular markers: domains D1-D3 of the large subunit (LSU), the internal transcribed spacer (ITS1, ITS2) plus 5.8S from the nuclear rDNA, and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1) from mitochondrial DNA. The new sequences were aligned with other sequences of Patagifer spp., downloaded from GenBank. Phylogenetic trees inferred from each data set, placed all the specimens in a clade, confirming that the isolates belonged to the same species. The morphological examination of specimens previously identified as P. lamothei by Ortega-Olivares MP, Hernández-Mena DI, Pérez-Ponce de León G, García-Varela M (2011) Helminths of the white ibis, Eudocimus albus (Aves Therskiornithidae) in Mexico. (Zootaxa 3088, 15-26. 10.11646/zootaxa.3088.1.2) and in combination with molecular data confirms that those specimens should be reassigned to P. bilobus. In addition, this is the first study in P. bilobus using an integrative taxonomy approach.
Asunto(s)
Echinostomatidae , Trematodos , Animales , Aves/parasitología , ADN de Helmintos/genética , ADN Ribosómico/genética , Echinostomatidae/genética , México , FilogeniaRESUMEN
Saccocoelioides is a genus of trematodes associated with fishes from the Americas. In the current research, morphologically distinct specimens of Saccocoelioides spp. were collected from six countries in Middle America. Specimens were sequenced using three molecular markers, the domains D1-D3 of the large subunit (LSU) from the nuclear rDNA, the cytochrome c oxidase subunit 1 (cox1) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1) from mitochondrial DNA. A total of 74 new sequences were compared and aligned with other sequences available in GenBank. Maximum likelihood and Bayesian inference analyses were inferred from the LSU and cox1 datasets, revealing unequivocally that all the specimens correspond to S. lamothei. A haplotype network was built with 119 sequences of the nad1 gene. The network detected 57 distinct haplotypes divided into three haplogroups. To explore morphological differences among samples of S. lamothei, 17 morphological features were measured from 53 specimens from three fish families: Eleotridae, Mugilidae and Gobiidae. Principal component analysis yielded three main polygons that corresponded with each family analysed, suggesting host-induced phenotypic plasticity. The current evidence suggests that S. lamothei infects at least five fish families along the Pacific coasts of Mexico, Guatemala, El Salvador, Honduras, Nicaragua and Costa Rica.
Asunto(s)
Adaptación Fisiológica , Enfermedades de los Peces/parasitología , Interacciones Huésped-Parásitos , Trematodos/fisiología , Infecciones por Trematodos/veterinaria , Animales , América Central , ADN de Helmintos/análisis , ADN Ribosómico/análisis , Agua Dulce/parasitología , Proteínas del Helminto/análisis , México , Océano Pacífico , Filogenia , Agua de Mar/parasitología , Trematodos/clasificación , Infecciones por Trematodos/parasitologíaRESUMEN
Members of the genus Tylodelphys Diesing, 1850 are endoparasites of fish-eating birds, particularly ciconiids, anhingids, and podicipedids across the globe. Metacercariae of Tylodelphys spp. were collected from the cranial and body cavities of freshwater fishes in central and northern Mexico; adults were recovered from the intestine of two species of freshwater diving birds of the family Podicipedidae, commonly known as grebes, in two locations of central Mexico. Specimens were sequenced for two molecular markers, the internal transcribed spacers (ITS1 and ITS2) plus 5.8S gene of the nuclear ribosomal DNA and of the cytochrome c oxidase subunit 1 from mitochondrial DNA. The genetic divergence among the 25 samples (16 metacercariae and 9 adults) and between the newly sequenced specimens and those deposited in the GenBank were estimated. Maximum likelihood and Bayesian inference analyses inferred with each data set revealed the existence of five genetic lineages. Eight metacercariae analyzed in this study were nested in two divergent lineages previously recognized as Tylodelphys sp. 5 and Tylodelphys sp. 6 (sensu Locke et al., Int J Parasitol, 45:841-855, 2015). Five adult specimens recovered from the intestine of the least grebe (Tachybaptus dominicus Linnaeus, 1766) in Tecocomulco Lake, Hidalgo State, nested in a single clade with other sequences identified previously as Tylodelphys aztecae, expanding its distribution range in other areas of central Mexico. The isolates of the metacercariae found in the cranial cavity of the shortfin silverside, Chirostoma humboldtianum Valenciennes, 1835 from Zacapu Lake in central Mexico formed a monophyletic lineage and were recognized as an undescribed species of Tylodelphys. The lack of adult specimens of this lineage in our samples prevented a formal description. However, the metacercariae collected in the cranial cavity of the silverside, Chirostoma jordani Woolman, 1894 and the adult specimens recovered from the intestine of the western grebe, Aechmophorus occidentalis (Lawrence, 1858) from Cuitzeo Lake formed a monophyletic clade, allowing us to link both stages of the life cycle and to describe this as a new species, Tylodelphys kuerepus n. sp. The new species represents the eighth species of the genus described in the Americas and the fourth in the Nearctic region. We briefly discuss the ecological associations between the metacercariae and their second intermediate hosts in relation to the genetic diversity patterns uncovered in our study.
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ADN de Helmintos/genética , ADN Mitocondrial/genética , Variación Genética , Metacercarias/genética , Trematodos/genética , Infecciones por Trematodos/veterinaria , Animales , Teorema de Bayes , ADN Espaciador Ribosómico/genética , Peces/parasitología , Lagos/parasitología , Metacercarias/clasificación , Metacercarias/crecimiento & desarrollo , Metacercarias/aislamiento & purificación , México , Filogenia , Trematodos/clasificación , Trematodos/crecimiento & desarrollo , Trematodos/aislamiento & purificación , Infecciones por Trematodos/parasitologíaRESUMEN
The increasing tendency of older people living alone may pose a number of challenges including factors related to food insecurity, such as functional impairment, social isolation, and financial vulnerability. The purpose of this study was to explain the cooking and eating behaviors of Mexican older women living alone using a life course perspective. A qualitative research methodology was chosen and deductive thematic analysis was used to examine accounts given by 14 older women through one-on-one interviews. Findings showed that age-related transitions, role changes, and the social context in which older women are embedded have changed their cooking and eating behaviors. Participants mentioned the need to accept and adapt to changes in later life; however, the loss of commensality, cooking for one, economic constraints, a decline in health, and the disruption of family roles and rituals were identified as the negative aspects affecting the cooking and eating behaviors of older women.
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Adaptación Psicológica , Culinaria , Conducta Alimentaria , Abastecimiento de Alimentos , Actividades Cotidianas , Anciano , Anciano de 80 o más Años , Conducta Alimentaria/etnología , Femenino , Estado de Salud , Humanos , Entrevistas como Asunto , Estilo de Vida , Persona de Mediana Edad , Investigación Cualitativa , Aislamiento Social , Factores Socioeconómicos , TelevisiónRESUMEN
The genus Neoechinorhynchus represents a hyper-diverse group of acanthocephalans, parasites of fresh and brackish water fish and freshwater turtles, with approximately 116 species described worldwide. Forty-nine species have been recorded in the Americas, nine of them in Middle America. Even though species delimitation methods using DNA sequences have been rarely used for parasitic helminths, the genetic library for species of Neoechinorhynchus has grown in the past few years, enhancing the possibility of using these methods for inferring evolutionary relationships and for establishing more robust species boundaries. In this study, we used non-tree-based and tree-based methods through a coalescent approach to explore the species limits of specimens of Neoechinorhynchus collected in 57 localities across Middle America. We sequenced a large number of individuals to build a comprehensive dataset for three genes: the mitochondrial cytochrome c oxidase subunit I (352 individuals), the internal transcribed spacers (330 individuals), and the D2â¯+â¯D3 domains of the large subunit (278 individuals). Several species delimitation methods were implemented, i.e., Automatic Barcode Gap Discovery (ABGD), General Mixed Yule-Coalescent Model (GMYC), Bayesian species delimitation (BPP) and species tree (∗BEAST). Additionally, we conducted a detailed morphological study of the diagnostic traits associated with the proboscis of 184 males and 169 females. Overall, our analyses allowed us to validate nine nominal species of Neoechinorhynchus and to identify 10 additional genetic lineages herein regarded as candidate species. This unexpected genetic diversity and the lack of reliable morphological traits show that the genus Neoechinorhynchus includes a group of cryptic species, at least in Middle America.
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Acantocéfalos/clasificación , Peces/parasitología , Agua Dulce , Acantocéfalos/genética , Animales , Teorema de Bayes , Complejo IV de Transporte de Electrones/genética , Femenino , Variación Genética , Geografía , Masculino , Fenotipo , Filogenia , Reproducibilidad de los Resultados , Especificidad de la Especie , Estados UnidosRESUMEN
We recently engaged in a two-part study of Clinostomum Leidy, 1856 across a geographic range comprising central Mexico southwards to Costa Rica, in Central America. In the first study, we investigated the species boundaries by using DNA sequences of mitochondrial and nuclear molecular markers, implementing several analytical tools and species delimitation methods. The result of that approach revealed five highly divergent genetic lineages that were interpreted as independent evolutionary units, or species. Here, we present the second part of the study, where we describe three of the five species for which we have sexually mature adult specimens obtained from the mouth cavity of fish-eating birds. Additionally, we characterise morphologically the metacercariae of the other two species, collected from freshwater fishes; these species cannot be formally described since no adults were found in their definitive hosts. We further discuss the characters that are more reliable for species identification within Clinostomum, such as the cirrus sac shape and relative position with respect to testes and ovary, the shape of the reproductive organs, and the diverticulated condition of the caeca.
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Enfermedades de las Aves/parasitología , Esófago/parasitología , Mucosa Bucal/parasitología , Trematodos/clasificación , Trematodos/aislamiento & purificación , Infecciones por Trematodos/veterinaria , Animales , Aves , Costa Rica , ADN Mitocondrial/genética , Enfermedades de los Peces/parasitología , Peces , Agua Dulce/parasitología , Marcadores Genéticos/genética , Metacercarias/genética , México , Filogenia , Trematodos/genética , Infecciones por Trematodos/parasitología , Estados UnidosRESUMEN
Mayarhynchus n. g. (Acanthocephala: Neoechinorhynchidae) is erected for Mayarhynchus karlae n. g, n. sp. described from the intestine of four species of cichlid fishes distributed from southeastern Mexico. The new genus placed in the family Neoechinorhynchidae (Ward, 1917) Van Cleave, 1928, is readily distinguished from the other 17 genera in the family by having a small proboscis armed with 45-46 relatively weak rooted hooks arranged in nine longitudinal rows of five hooks each. In addition, Mayarhynchus n. g., n. sp. is diagnosed by the presence of a short trunk, body wall with five dorsal and one ventral giant hypodermal nuclei, proboscis receptacle nearly cylindrical with single layered wall, lemnisci broad and flat with large nuclei, testes in tandem, cement gland with eight large nuclei, and eggs elongate to oval. Partial sequences of the cytochrome c oxidase subunit 1 (cox1), internal transcribed spacers (ITS1 + 5.8S + ITS2), and the D2-D3 domains of the large subunit rRNA gene (28S) were obtained for five specimens of the new species and other species belonging to the Neoechinorhynchidae. Phylogenetic analyses confirmed that the new genus belongs to the Neoechynorhynchidae and indicated that the genus Neoechynorhynchus Stiles & Hassall, 1905 is not monophyletic. Comparison between three populations of the new species yielded nine variable sites for cox1, 11 for ITS and four for 28S.
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Acantocéfalos/clasificación , Cíclidos/parasitología , Filogenia , Acantocéfalos/genética , Animales , ADN Espaciador Ribosómico/genética , Complejo IV de Transporte de Electrones/genética , Intestinos/parasitología , México , ARN Ribosómico 28S/genética , Especificidad de la EspecieRESUMEN
The recent development of genetic methods allows the delineation of species boundaries, especially in organisms where morphological characters are not reliable to differentiate species. However, few empirical studies have used these tools to delineate species among parasitic metazoans. Here we investigate the species boundaries of Clinostomum, a cosmopolitan trematode genus with complex life cycle. We sequenced a mitochondrial [cytochrome c oxidase subunit I (COI)] gene for multiple individuals (adults and metacercariae) from Middle-America. Bayesian phylogenetic analysis of the COI uncovered five reciprocally monophyletic clades. COI sequences were then explored using the Automatic Barcode Gap Discovery to identify putative species; this species delimitation method recognized six species. A subsample was sequenced for a nuclear gene (ITS1, 5·8S, ITS2), and a concatenated phylogenetic analysis was performed through Bayesian inference. The species delimitation of Middle-American Clinostomum was finally validated using a multispecies coalescent analysis (species tree). In total, five putative species are recognized among our samples. Mapping the second intermediate hosts (fish) onto the species tree suggests that metacercariae of these five species exhibit some level of host specificity towards their fish intermediate host (at the family level), irrespective of geographical distribution.
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Variación Genética , Filogenia , Trematodos/clasificación , Trematodos/genética , Animales , América Central , Análisis por Conglomerados , ADN de Helmintos/química , ADN de Helmintos/genética , ADN Espaciador Ribosómico/química , ADN Espaciador Ribosómico/genética , Complejo IV de Transporte de Electrones/genética , Análisis de Secuencia de ADNRESUMEN
Among the acanthocephalans, Neoechinorhynchus is one of the most speciose genera, with 116 described species distributed worldwide. The adults of Neoechinorhynchus are found in the intestine of freshwater and brackish water fish, as well as in freshwater turtles. In this study, a checklist of the congeneric species of Neoechinorhynchus occurring in Middle-American fish and turtles is presented. The checklist contains the records established in all published accounts, as well as novel data from survey work conducted in the region comprising Neotropical areas of Mexico, as well as some localities in Central America. The species delimitation criteria used to discriminate among species is based on molecular data. In the last years, a large database derived from sequences of the D2 + D3 domains of the large subunit of rDNA (28S) was generated for 262 specimens corresponding to nine species of Neoechinorhynchus. This molecular marker has shown to be useful in establishing species limits within Neoechinorhynchus and in resolving phylogenetic relationships at species level. Based on our results, the domains D2 + D3 of the 28S rDNA could be considered as potential DNA barcodes to complement mitochondrial DNA to discriminate among acanthocephalan species.
Asunto(s)
Acantocéfalos/clasificación , Enfermedades de los Peces/parasitología , Helmintiasis Animal/parasitología , ARN Ribosómico 28S/genética , Tortugas/parasitología , Acantocéfalos/anatomía & histología , Acantocéfalos/genética , Acantocéfalos/crecimiento & desarrollo , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , América Central , Lista de Verificación , ADN de Helmintos/genética , ADN Ribosómico/genética , Femenino , Peces , Intestinos/parasitología , Masculino , México , Tamaño de los Órganos , FilogeniaRESUMEN
BACKGROUND AND OBJECTIVES: Transorbital neuroendoscopic surgery (TONES) is continuously evolving and gaining terrain in approaching different skull base pathologies. The objective of this study was to present our methodology for introducing recording electrodes, which includes a new transconjunctival pathway, to monitor the extraocular muscle function during TONES. METHODS: A translational observational study was performed from an anatomic demonstration focused on the transconjunctival electrode placement technique to a descriptive analysis in our series of 6 patients operated using TONES in association with intraoperative neurophysiologic monitoring of the oculomotor nerves from 2017 to 2023. The stepwise anatomic demonstration for the electrode placement and correct positioning in the target muscle was realized through cadaveric dissection. The descriptive analysis evaluated viability (obtention of the electromyography in each cranial nerve [CN] monitored), security (complications), and compatibility (interference with TONES). RESULTS: In our series of 6 patients, 16 CNs were correctly monitored: 6 (100%) CNs III, 5 (83.3%) CNs VI, and 5 (83.3%) CNs IV. Spontaneous electromyography was registered correctly, and compound muscle action potential using triggered electromyography was obtained for anatomic confirmation of structures (1 CN III and VI). No complications nor interference with the surgical procedure were detected. CONCLUSION: The methodology for introducing the recording electrodes was viable, secure, and compatible with TONES.