Phylogeography of the Central American lancehead Bothrops asper (SERPENTES: VIPERIDAE)

The uplift and final connection of the Central American land bridge is considered the major event that allowed biotic exchange between vertebrate lineages of northern and southern origin in the New World. However, given the complex tectonics that shaped Middle America, there is still substantial controversy over details of this geographical reconnection, and its role in determining biogeographic patterns in the region. Here, we examine the phylogeography of Bothrops asper, a widely distributed pitviper in Middle America and northwestern South America, in an attempt to evaluate how the final Isthmian uplift and other biogeographical boundaries in the region influenced genealogical lineage divergence in this species. We examined sequence data from two mitochondrial genes (MT-CYB and MT-ND4) from 111 specimens of B. asper, representing 70 localities throughout the species’ distribution. We reconstructed phylogeographic patterns using maximum likelihood and Bayesian methods and estimated divergence time using the Bayesian relaxed clock method. Within the nominal species, an early split led to two divergent lineages of B. asper: one includes five phylogroups distributed in Caribbean Middle America and southwestern Ecuador, and the other comprises five other groups scattered in the Pacific slope of Isthmian Central America and northwestern South America. Our results provide evidence of a complex transition that involves at least two dispersal events into Middle America during the final closure of the Isthmus

Genotypic diversity of Acanthamoeba strains isolated from Chilean patients with Acanthamoeba keratitis

Acanthamoeba spp. are the causative agents of a severe keratitis occurring mainly in contact lens wearers. The genus comprises more than 24 species that are currently divided into 20 different genotypes (T1-T20) according to sequence variations in the 18S rRNA gene. The objective of this study was to identify the genotypes and sub-genotypes of Acanthamoeba isolates collected at the Parasitology Laboratory of the Public Health Institute of Chile, the only laboratory in the country where Acanthamoeba screening is performed. This is the first report of genotypic identification of clinical isolates of Acanthamoeba in Chile and one of the few in South America. T2, T4 and T11 genotypes were predominantly isolated from the Acanthamoeba keratitis patients in Chile. Chilean predominant T4 sub-genotypes, which have also been reported worldwide, formed a separate cluster of the minority T4 variants. This study provides useful information about the predominant genotypes and subgenotypes that would be useful in selecting suitable strains to develop immunological and/or molecular diagnostic assays in Chile

The macroecology of chemical communication in lizards: do climatic factors drive the evolution of signalling glands?

Chemical communication plays a pivotal role in shaping sexual and ecological interactions among animals. In lizards, fundamental mechanisms of sexual selection such as female mate choice have rarely been shown to be influenced by quantitative phenotypic traits (e.g., ornaments), while chemical signals have been found to potentially influence multiple forms of sexual and social interactions, including mate choice and territoriality. Chemical signals in lizards are secreted by glands primarily located on the edge of the cloacae (precloacal glands, PG) and thighs (femoral glands), and whose interspecific and interclade number ranges from 0 to >100. However, elucidating the factors underlying the evolution of such remarkable variation remains an elusive endeavour. Competing hypotheses suggest a dominant role for phylogenetic conservatism (i.e., species within clades share similar numbers of glands) or for natural selection (i.e., their adaptive diversification results in deviating numbers of glands from ancestors). Using the prolific Liolaemus lizard radiation from South America (where precloacal glands vary from 0-14), we present one of the largest-scale tests of both hypotheses to date. Based on climatic and phylogenetic modelling, we show a clear role for both phylogenetic inertia and adaptation underlying gland variation: (i) solar radiation, net primary productivity, topographic heterogeneity and precipitation range have a significant effect on number of PG variation, (ii) humid and cold environments tend to concentrate species with a higher number of glands, (iii) there is a strong phylogenetic signal that tends to conserve the number of PG within clades. Collectively, our study confirms that the inertia of niche conservatism can be broken down by the need of species facing different selection regimes to adjust their glands to suit the demands of their specific environments

Toxinological, clinical and epidemiological aspects of the envenomation produced by the scorpion Tityus fuhrmanni Kraepelin

Con el objetivo de determinar las características toxinológicas, clínicas y epidemiológicas del envenenamiento producido por el escorpión T. fuhrmanni, se realizó durante un año un estudio prospectivo en un sector de la ciudad de Medellín (cerro El Volador y los barrios aledaños San Germán y El Volador), en una muestra del9,6% de las casas (180) y del 9,4% de la población del área (719 habitantes). Se incluyó también la recolección de especímenes vivos (128) y de veneno para la parte experimental. La dispersión de escorpiones para el área de estudio fue del 100%, con alta infestación domiciliaria en las viviendas del cerro y del barrio San Germán (100% y 32,3%, respectivamente). Durante todo el estudio se detectaron 32 accidentes por T.fuhrmanni, 7 (21,9%) en niños, 15 en el cerro y 10 en el barrio San Germán, con tasas de ataque del 83% y del 3,9%, respectivamente. Dieciocho (56,3%) accidentes ocurrieron en el interior de las viviendas, principalmente en las manos (31,3%), la cabeza y el cuello (18,8%) y durante la noche o en las primeras horas de la mañana (62,5%). El 90,6% de los casos fueron leves y el 9,4% (3 niños) tuvieron envenenamiento moderado con signos sistémicos (sudoración generalizada, dolor abdominal). No hubo casos graves y los pacientes no requirieron hospitalización. Tityus fuhrmanni produjo 0,56 ± 0,27 mg de veneno por ordeño, ysu DL50 (i.p.) en ratones (18-20 g) fue 79,2 μg (3,9 mg veneno/kg). Los animales presentaron sialorrea, piloerección, somnolencia, sudoración generalizada, taquipnea, cianosis, ataxia y convulsiones antes de morir. La rápida aparición (10-15 min) de los signos de envenenamiento en los ratones y su pronta desaparición(2 horas) en los sobrevivientes, permiten concluir que el veneno es de rápida absorción, distribución y eliminación. [Gómez JP, Otero R, Núñez V, Saldarriaga M, Díaz A, Velásquez P. Aspectos toxinológicos, clínicos y epidemiológicos del envenenamiento producido por el escorpión Tityus fuhrmanni Kraepelin.MEDUNAB 2002; 5(15): 159-65]In order to determine the toxinological, clinical and epidemiological characteristics of the poisoning produced by the scorpion T. fuhrmanni, a prospective study was carried out for a year in a sector of the city of Medellín (Cerro El Volador and the neighboring neighborhoods San Germán and El Volador), in a sample of 9.6% of the houses (180) and 9.4% of the population of the area (719 inhabitants). The collection of live specimens (128) and poison for the experimental part was also included. The dispersion of scorpions for the study area was 100%, with high home infestation in the homes of the hill and the San Germán neighborhood (100% and 32.3%, respectively). Throughout the study, 32 accidents were detected by T. fuhrmanni, 7 (21.9%) in children, 15 in the hill and 10 in the San Germán neighborhood, with attack rates of 83% and 3.9%, respectively. . Eighteen (56.3%) accidents occurred inside homes, mainly in the hands (31.3%), head and neck (18.8%) and during the night or in the early hours of the morning (62.5%). 90.6% of the cases were mild and 9.4% (3 children) had moderate poisoning with systemic signs (generalized sweating, abdominal pain). There were no serious cases and the patients did not require hospitalization. Tityus fuhrmanni produced 0.56 ± 0.27 mg of venom per milking, and its LD50 (i.p.) in mice (18-20 g) was 79.2 μg (3.9 mg venom / kg). The animals presented with salivation, piloerection, drowsiness, generalized sweating, tachypnea, cyanosis, ataxia and seizures before dying. The rapid appearance (10-15 min) of the poisoning signs in the mice and their prompt disappearance (2 hours) in the survivors, allow us to conclude that the venom is of rapid absorption, distribution and elimination. [Gómez JP, Otero R, Núñez V, Saldarriaga M, Díaz A, Velásquez P. Toxinological, clinical and epidemiological aspects of the poisoning produced by the scorpion Tityus fuhrmanni Kraepelin.MEDUNAB 2002; 5 (15): 159-65

Comparative pan-genomic analysis of 51 Renibacterium salmoninarum indicates heterogeneity in the principal virulence factor, the 57 kDa protein

Indexación: Scopus.Renibacterium salmoninarum, a Gram-positive intracellular pathogen, is the causative agent of bacterial kidney disease (BKD), the impacts of which are high mortalities and economic losses for the salmon industry. This study provides novel analyses for the whole-genome sequences of 50 R. salmoninarum isolates and the reference strain ATCC 33209 using a pan-genomic approach to elucidate phylogenomic relationships and identify unique and shared genes associated with pathogenicity and infection mechanisms. Genome size varied from 3,061,638 to 3,155,332 bp; gene count from 3452 to 3580; and predicted coding sequences from 3402 to 3527. Comparative analyses revealed an open, but approaching closed, pan-genome. The pan-genome analysis recovered 4064 genes, with a core genome containing 3306 genes. Phylogenetic analysis of R. salmoninarum showed high genomic homogeneity, apart from one isolate obtained from Salmo trutta in Norway. All genomes presented the 57-kDa protein (p57). Strain ATCC 33209 and the Chilean isolates H-2 and DJ2R presented two copies of the msa gene, while the remaining isolates had one copy. The pan-genome analysis further identified differences in the number of copies and length of the signalling peptide for p57, the principal virulence factor reported for this bacterium. This heterogeneity could be associated with the secretion levels of p57, potentially influencing virulence. Additionally identified were numerous common genes related to iron uptake, the stress response and regulation, and cell signalling—all of which constitute the pathogenic repertoire of R. salmoninarum. This investigation provides information that is applicable in future studies for identifying therapeutic targets and/or for designing new strategies (e.g., vaccines) to prevent BKD infections in salmon farming. © 2022 John Wiley & Sons Ltd.https://onlinelibrary.wiley.com/doi/10.1111/jfd.13653This work was supported by grant FONDAP 15110027 awarded by the Agencia Nacional de Investigación y Desarrollo (ANID, Chile). We also thank Dr. Sion Bayliss from University of Bath, UK, who facilitated access to the accession numbers of the R. salmoninarum genomes and information used in our study.S

Los escorpiones: aspectos ecológicos, biológicos y toxinológicos

ResumenLos escorpiones son artrópodos quelicerados distribuidos en las regiones tropicales y subtropicales del mundo. Su veneno es una mezcla bioquímica compleja, formada principalmente por proteinas neurotóxicas de bajo peso molecular que ejercen su acción sobre los canales iónicos, ocasionando efectos nocivos en sus victimas.Palabras clave: Escorpiones, toxínas, canales iónicos

Draft Genome Sequence of Tenacibaculum ovolyticum To-7Br, Recovered from a Farmed Atlantic Salmon (Salmo salar)

Indexación: Scopus.We present the draft genome sequence of Tenacibaculum ovolyticum isolate To-7Br, recovered from a gill of a farmed specimen of Atlantic salmon (Salmo salar) showing signs of tenacibaculosis. This study provides the first detailed insights into the genomic characteristics of T. ovolyticum isolated for the first time from fish farmed in Chile. © 2022 Avendaño-Herrera et al.https://journals-asm-org.recursosbiblioteca.unab.cl/doi/epub/10.1128/mra.00254-2

Revision of the New World species of the genus Pelecorhynchus Macquart, 1850 (Diptera: Pelecorhynchidae)

Llanos, Lorena, Gonzalez, Christian R., Córdoba, Mónica Saldarriaga (2015): Revision of the New World species of the genus Pelecorhynchus Macquart, 1850 (Diptera: Pelecorhynchidae). Zootaxa 3955 (2): 188-210, DOI: http://dx.doi.org/10.11646/zootaxa.3955.2.

Draft Genome Sequence of Tenacibaculum ovolyticum To-7Br, Recovered from a Farmed Atlantic Salmon ( <i>Salmo salar</i> )

We present the draft genome sequence of Tenacibaculum ovolyticum isolate To-7Br, recovered from a gill of a farmed specimen of Atlantic salmon ( Salmo salar ) showing signs of tenacibaculosis. This study provides the first detailed insights into the genomic characteristics of T. ovolyticum isolated for the first time from fish farmed in Chile. </jats:p

New salmonid hosts for Tenacibaculum species: Expansion of tenacibaculosis in Chilean aquaculture

The success and sustainability of Chilean aquaculture largely depends on the control of endemic and emerging pathogens, including several species of the genus Tenacibaculum. Tenacibaculum dicentrarchi and “Tenacibaculum finnmarkense” have been detected and confirmed in Chilean Atlantic salmon (Salmo salar). However, no outbreaks of tenacibaculosis in rainbow trout (Oncorhynchus mykiss) or coho salmon (Oncorhynchus kisutch) have been reported, either in Chile or globally. The aims of this study were to determine whether the mortalities recorded for rainbow trout and coho salmon from five marine fish farms located in the Los Lagos, Aysén, and Magallanes Regions could be caused by Tenacibaculum spp. The diseased fish exhibited cutaneous haemorrhages, tail and peduncle rots, and damage on the mouth and tongue. Microbiological analysis of infected external tissues yielded 13 bacterial isolates. The isolates were identified as members of the genus Tenacibaculum through biochemical analysis (e.g. Gram-stain negative, straight rods, filamentous cells and motile by gliding), but differences existed in biochemical results, making species-level identification through biomolecular tools essential. The 16S rRNA analysis found that the majority of isolates were more closely related to “T. finnmarkense” than T. dicentrarchi, while the phylogenetic trees resulting from multilocus sequence data recovered the four main clades (clades I to IV) identified by Olsen et al. (2017, Veterinary Microbiology, 205, 39). This is the first documented occurrence of clinical tenacibaculosis in farmed rainbow trout and coho salmon globally, and it extends the known host distribution of this pathogen in Chile. Moreover, we confirm the presence of Tenacibaculum species in the Chilean Patagonia. These findings highlight the importance of establishing preventative measures to minimize the spread of this disease within the Chilean marine aquaculture industry, as well as the need for monitoring initiatives worldwide in these farmed fish species. © 2020 John Wiley & Sons LtdIndexación: Scopu