Mauro Nirchio

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• MSc; PhD
• Professor (Full) at Universidad Tecnica de Machala

Environmental monitoring requires reliable bioindicators to assess the genotoxic effects of pollutants in aquatic ecosystems. In this study, the marine fish Thalassophryne maculosa was evaluated as a bioindicator of genotoxicity through the application of the micronucleus test. Fish were exposed to varying concentrations of mercuric chloride (HgCl2...

El papel fundamental de los peces es mantener el equilibrio en el ecosistema, por su adaptabilidad. La diversidad genética y estructura cromosómica refleja la biología evolutiva a través de técnicas de cariotipado, bandeo cromosómico e hibridación fluorescente y permite conocer la biología de los peces. A través del análisis citogenético se definen...

Congenital anomalies are rare in veterinary medicine, and their aetiology, development, clinical presentation, and management remain poorly understood. This study documents a rare case of multiple congenital anomalies occurring simultaneously in a single individual. We present a comprehensive analysis of a 4-month-old mixed-breed puppy diagnosed wi...

Astroblepus species, commonly known as Andean climbing catfish, exhibit a unique challenge in species delimitation, leading to ongoing taxonomic debates. Here we report data on Astroblepus mindoensis, a vulnerable species endemic to Ecuador, obtained by an integrative approach that includes cytogenetic analysis, molecular identification of the spec...

La Ehrlichiosis monocítica canina (EMC), una enfermedad emergente causada por Ehrlichia canis. Este patógeno se encuentra comúnmente en perros y otros canidos silvestres que actúan como reservorios naturales. La EMC es prevalente en regiones tropicales y subtropicales, por la presencia de la garrapata marrón del perro, Rhipicephalus sanguineus, que...

RESUMEN Se presenta el estudio de un perro con sintomatología de Parvovirosis que resultó positivo a los test de inmunocromatografìa para Parvovirus y Ehrlichia canis el cual fue confirmado, a nivel molecular, como positivo para E. canis y E. ewingii. Además del interés que representa este caso desde el punto de vista clínico, la detección mediante...

En esta investigación, se analiza la dinámica de las respuestas hematológicas en Orthopristis rubra abordando los impactos durante la captura, el transporte y el estrés inducido por el confinamiento. Abarcando 504 horas, el estudio captura los cambios en las variables hematológicas durante la aclimatación de esta especie en ambientes artificiales....

Mammary cancer is a disease that requires effective treatments. Conventional chemotherapy, while effective, often causes harmful side effects. In contrast, metronomic chemotherapy (mCHT), which involves the continuous administration of low doses of anticancer drugs, is presented as a less aggressive alternative. In this study, the genotoxic impact...

In this research, the dynamics of blood responses in Orthopristis rubra are analyzed addressing the impacts during capture, transport, and confinement-induced stress. Spanning 504 hours, the study captures the changes in hematological variables during the acclimatization of this species in artificial environments. The results obtained from two grou...

The plecos (Loricariidae) fish represent a great model for cytogenetic investigations due to their variety of karyotypes, including diploid and polyploid genomes, and different types of sex chromosomes. In this study we investigate Transancistrus santarosensis a rare loricariid endemic to Ecuador, integrating cytogenetic methods with specimens’ mol...

Ancistrus Kner, 1854, is the most diverse genus among the Ancistrini (Loricariidae) with 70 valid species showing a wide geographic distribution and great taxonomic and systematic complexity. To date, about 40 Ancistrus taxa have been karyotyped, all from Brazil and Argentina, but the statistic is uncertain because 30 of these reports deal with sam...

Mulinia lateralis is a native bivalve from the Western Atlantic Ocean, distributed from the Gulf of Saint Lawrence in Canada to Yucatan in Mexico. Based on morphological and genetic data of specimens collected in shrimp farms, in this work, we confirm the presence of M. lateralis in the Gulf of Guayaquil, Ecuador. Presence and its consequences of t...

Pomatomus saltatrix is a high-value marine pelagic coastal fish, that is fished throughout subtropical and temperate coastal waters around the world. Despite its large economic potential, there are no global data on its genetic diversity, which could compromise the conservation of the species. The aim of this study was to analyse the genetic-evolut...

Despite several difficulties in chromosomal analyses of small-sized fishes, the cytogenetics of the Lebiasinidae was largely improved in the last years, showing differential patterns in the chromosomal evolution inside the family. In this context, it has been shown that genus Lebiasina preserves its karyotypic macrostructure, composed of 2n = 36 ch...

This work provides the first detailed report on diploid number, karyotype formula, distribution of constitutive heterochromatin and nucleolus organizing regions (NORs) in Sparisoma chrysopterum (BlocH & scHneider 1801). The species has a modal diploid number 2n = 46 chromosomes composed of 8 metacentric (m), 10 submetacentric (sm), 10 subtelocentri...

The effect of extreme salinities on survival, body water percentage, condition index, leucine aminopeptidase-I (LAP) enzyme activity and allelic frequencies at the LAP-2 * and LAP-3* loci of C. rhizhophorae, were studied. Sudden exposure caused 46.5% mortality at 5 PSU and 45.25% at 60 PSU after 96 hours. The highest values of body water were 82.18...

RESUMEN: Se presenta el análisis morfométrico multivariado para cuatro de las siete especies del género Mugil reportadas para Venezuela (Mugil trichodon, M. liza, M. margaritae y M. rubrioculus), separadas con base en sus características citogenéticas (número diploide, formula cariotípica y la posición de las regiones organizadoras del nucléolo), p...

Se presentan los resultados de un estudio citogenético realizado en dos hembras caninas de raza Pinscher Miniatura que murieron después de nacer, una afectada con meningoencefalocele (MEC) y la otra aparentemente normal. El análisis de 156 metafases (75 del ejemplar con patología y 81 sin patología) mostró un complemento femenino unimodal típico 2n...

Parodontidae is a relatively small group of Neotropical characiform fishes consisting of three genera (Apareiodon, Parodon, and Saccodon) with 32 valid species. A vast cytogenetic literature is available on Apareiodon and Parodon, but to date, there is no cytogenetic data about Saccodon, a genus that contains only three species with a trans-Andean...

The results of electrophoresis of the blood serum of Lutjanus analis in agarose gel from two groups of fishes: (a) fish exposed to live Listonella anguillarum diluted in 0.9% NaCl solution (saline) by intramuscular injection and (b) control specimens injected with the saline solution are provided. Differences in the serum protein profiles of the tw...

The freshwater fish species Dormitator latifrons, commonly named the Pacific fat sleeper, is an important food resource in CentralSouth America, yet almost no genetic information on it is available. A cytogenetic analysis of this species was undertaken by standard and molecular techniques (chromosomal mapping of 18S rDNA, 5S rDNA, and telomeric rep...

Lebiasinidae fishes have been historically neglected by cytogenetical studies. Here we present a genomic comparison in eleven Lebiasinidae species, in addition to a review of the ribosomal DNA sequences distribution in this family. With that, we develop ten sets of experiments in order to hybridize the genomic DNA of representative species from the...

Neotropical cichlids include hundreds of species whose taxonomy has benefited of molecular phylogeny and whose karyotype evolution has been related to the amount and distribution of different classes of repetitive sequences. This study provides the first integrative molecular (cytochrome c oxidase subunit 1 and 16S sequences) and cytogenetic analys...

La tilapia es un pez dulceacuícola originario del África que posee muchas características que la convierten en un excelente pez para acuicultura, pero también es considerada como una de las especies exóticas invasoras más peligrosas del mundo debido a su adaptabilidad y potencial reproductivo. En este ensayo se analiza el dilema entre las bondades...

Mugil setosus Gilbert 1892 was originally described by Gilbert based on specimens from Clarion Island, in the western and most remote of the Revillagigedo Islands, about 1,000 km off the western Pacific coast of Mexico. Examination of the type of material and recently collected specimens from Ecuador and Peru, resulted in the redescription provided...

Understanding the effects of heavy metals in aquatic ecosystems is of significant importance due to their potential to bioaccumulate at various trophic levels and induce damage in DNA. Mercury is considered one of the most dangerous heavy metals, causing chromosomal breakage (clastogenic event) or spindle dysfunction (aneugenic event), that can lea...

Understanding the effects of heavy metals in aquatic ecosystems is of significant importance due to their potential to bioaccumulate at various trophic levels and induce damage in DNA. Mercury is considered one of the most dangerous heavy metals, causing chromosomal breakage (clastogenic event) or spindle dysfunction (aneugenic event), that can lea...

El objetivo de la investigación fue evaluar las propiedades químicas y biológicas de extractos acuosos e hidroalcohólicos del pseudotallo de Musa x paradisiaca L. La materia prima vegetal fue caracterizada mediante análisis físico-químicos. El estudio químico cualitativo de los extractos se realizó a través de un tamizaje fitoquímico, por cromatogr...

We present the first cytogenetic data for Lebiasina bimaculata and L. melanoguttata with the aim of (1) investigating evolutionary events within Lebiasina and their relationships with other Lebiasinidae genera and (2) checking the evolutionary relationships between Lebiasinidae and Ctenoluciidae. Both species have a diploid number 2n = 36 with simi...

The pearly razorfish Xyrichtys novacula (Linnaeus, 1758) is a sedentary benthic species distributed in both sides of the Atlantic Ocean and in the Mediterranean Sea. Previous cytogenetic analysis reported different diploid numbers in samples from Italy, Venezuela and Brazil. This research aims to test the hypothesis that samples from American Atlan...

The study of mercury content in marine sediments is presented in nine sampling stations of Estero Huaylá in Puerto Bolívar (Ecuador), by means of spectrophotometry of atomic absorption with flame nebulization and with the generation of hydrides with atomization in a quartz cell. The ecological risk assessment was determined by calculating the pollu...

Mullets are very common fishes included in the family Mugilidae, (Mugiliformes), which are characterized by both a remarkably uniform external morphology and internal anatomy. Recently, within this family, different species complexes were molecularly identified within Mugil, a genus which is characterized by lineages that sometimes show very differ...

The Mugil curema species complex (Pisces, Mugilidae): a new karyotype for the Pacific white mullet mitochondrial lineage. Comparative Cytogenetics 11(2): 225–237. https://doi. Abstract Recent molecular phylogenetic analyses have shown that the Mugil curema Valenciennes, 1836 species complex includes M. incilis Hancock, 1830, M. thoburni (Jordan & S...

We used conventional cytogenetic techniques (Giemsa, C-banding, Ag-NOR), and fluorescent in situ hybridization (FISH) with 5S and 18S rDNA probes to investigate the karyotype and cytogenetic characteristics of Ichthyoelephas humeralis (Günther, 1860) from Ecuador. The specimens studied have a karyotype with 2n=54 biarmed chromosomes (32 M + 22 SM)...

Cytogenetic and molecular analyses enabled identification of two cytotypes among individuals of the spotted scorpion fish Scorpaena plumieri from Margarita Island, Venezuela. Cytotype 1 was characterized by 48 subtelo-acrocentric chromosomes and fundamental number (number of chromosome arms; FN) equalled 48, while cytotype 2 was characterized by tw...

We report on the results of the cytogenetic study of Scorpaena brasiliensis and S. isthmensis from Venezuela by conventional Giemsa staining and silver staining. S. brasiliensis has a complement 2n= 46 composed of two metacentric (M), 8 submetacentric (SM) and 36 subtelo/acrocentric (ST/A), NF= 56 with NORs located in the terminal position of the s...

Karyotypic features of Rhoadsia altipinna Fowler, 1911 from Ecuador were investigated by examining metaphase chromosomes through Giemsa staining, C-banding, Ag-NOR, and two-color-fluorescence in situ hybridization (FISH) for mapping of 18S and 5S ribosomal genes. The species exhibit a karyotype with 2n = 50, composed of 10 metacentric, 26 submetace...

Analysis of morphological, molecular and cytological data helped to define and more precisely characterize the species of Mugil from the Atlantic coasts of South Caribbean and South America, allowing a correction of prior misidentifications and distributional ranges. A new species from Venezuela is described and all the species from the area are re...

Analysis of morphological, molecular and cytological data helped to define and more precisely characterize the species of Mugil from the Atlantic coasts of South Caribbean and South America, allowing a correction of prior misidentifications and distributional ranges. A new species from Venezuela is described and all the species from the area are re...

Se presenta una descripción general de las técnicas básicas y moleculares más comúnmente empleadas para el estudio de los cromosomas en los peces con ejemplos que demuestran la utilidad de la citogenética para resolver problemas de tipo taxonómico, particularmente cuando las características merísticas y morfométricas no permiten una clara diferenci...

Se presenta una base de datos que contiene los datos citogenéticos de peces Actinopterigios Neotropicales de Venezuela obtenidos por primera vez en un solo laboratorio. Los resultados de este estudio incluyen 103 especies pertenecientes a 74 géneros de 45 familias contenidas en 17 de los 40 órdenes de teleósteos. En el grupo de peces marinos, el nú...

The genus Pterois includes nine valid species, native to the Red Sea and Indian Ocean throughout the Western Pacific. P. volitans and P. miles are native to the Indo-Pacific, and were introduced into Florida waters as a result of aquarium releases, and have been recently recognized as invaders of the Western Atlantic and Caribbean Sea (Costa Rica t...

Texture is the most valuable feature in cephalopods. Factors that mainly affect the texture of octopus are: freezing, scalding and cooking. The aim of this study was to assess the effect of freezing, scalding and length of cooking time on the texture and electrophoretic pattern of proteins of octopus arms. Octopuses were trapped near Margarita Isla...

The abundance and wide distribution of mullets in the tropical, subtropical, and temperate regions of all continents make them a very important commercial species in fisheries and aquaculture of many regions in the world. However, the similar morphology among several species that inhabit all oceans makes it difficult to accurately determinemorpholo...

La textura es la característica más valorada en los cefalópodos. Los factores que principalmente afectan la textura del pulpo son congelación, escaldado y cocción. El objetivo de esta investigación fue evaluar el efecto de la congelación, escaldado y diferentes tiempos de cocción sobre la textura y perfil electroforético de las proteínas de brazos...

The genus Pseudoplatystoma includes catfish species distributed throughout the fresh waters of South America. These species are important fisheries resources and play a significant ecological role due to their piscivorous and migratory habits. The taxonomy of this genus is still debated: traditionally, only three species have been recognised, but r...

The family Loricariidae with 813 nominal species is one of the largest fish families of the world. Hypostominae, its more complex subfamily, was recently divided into five tribes. The tribe Hypostomini is composed of a single genus, Hypostomus Lacépède, 1803, which exhibits the largest karyotypic diversity in the family Loricariidae. With the main...

The family Loricariidae with about 690 species divided into six subfamilies, is one of the world's largest fish families. Cytogenetic studies conducted in the family showed that among 90 species analyzed the diploid number ranges from 2n=38 in Ancistrus sp. to 2n=96 in Hemipsilichthys gobio Luetken, 1874. In the present study, fluorescence in situ...

Cytogenetic analysis by conventional Giemsa staining, AgNO3-impregnation for revealing Nucleolus OrganizerRegions (NOR), and C-banding in Opistognathus macrognathus revealed a diploid modal chromosome complement of 2n=40composed by 2 metacentric, 6 submetacentric, 4 subtelocentric and 28 acrocentric elements. Sequential Silver nitrateimpregnation o...

This study reports the description of the karyotype of Mugil incilis from Venezuela. The chromosome complement is composed of 48 acrocentric chromosomes, which uniformly decrease in size. Therefore, the homologues can not be clearly identified, with the exception of one of the largest chromosome pairs, classified as number 1, whose homologues may s...

The first cytogenetic analysis by conventional Giemsa staining, silver nitrate impregnation of nucleolus organizer regions (Ag-NOR), and fluorescence in situ hybridization (FISH) carried out on Ophisternon aenigmaticum from Margarita Island, Venezuela, is reported. Two cytotypes were found: cytotype C1, 2n=46, composed of 6 medium size metacentrics...

The first cytogenetic analysis by conventional Giemsa staining, silver nitrate impregnation of nucleolus organizer regions (Ag-NOR), and fluorescence in situ hybridization (FISH) carried out on Ophisternon aenigmaticum from Margarita Island, Venezuela, is reported. Two cytotypes were found: cytotype C1, 2n=46, composed of 6 medium size metacentrics...

A cytogenetic analysis by conventional Giemsa staining, silver staining, C-banding, and fluorescence in situ hybridization (FISH) was carried out on Brycon amazonicus from Caicara del Orinoco, Venezuela. The karyotype of this species is characterized by the presence of 2n = 50 chromosomes, a karyotypic formula 22m+14sm+14st, and a fundamental numbe...

The identification of the lebranche mullet in the western south Atlantic has long been problematical. In most recent works either Mugil liza Valenciennes and M. platanus Günther, 1880 or M. liza and M. cephalus Linnaeus, 1758 were recognized from the region and more rarely the occurrence of only one species has been proposed but without sufficient...

The identification of the lebranche mullet in the western south Atlantic has long been problematical. In most recent works either Mugil liza Valenciennes and M. platanus Günther, 1880 or M. liza and M. cephalus Linnaeus, 1758 were recognized from the region and more rarely the occurrence of only one species has been proposed but without sufficient...

Available chromosomal data for the Cichlidae clade. n, haploid number; 2n, diploid number; KF, karyotypic formulae; NOR, nucleolus organizer region; m/sm, meta-submetacentric chromosomes; st/a, subtelo-acrocentric chromosomes; a, acrocentric chromosomes. The species are distributed in subfamilies and tribes according to [13]. The data presented her...

Cichlid fishes have been the subject of increasing scientific interest because of their rapid adaptive radiation which has led to an extensive ecological diversity and their enormous importance to tropical and subtropical aquaculture. To increase our understanding of chromosome evolution among cichlid species, karyotypes of one Asian, 22 African, a...

Despite their ecological and economical importance, fishes of the family Ariidae are still genetically and cytogenetically poorly studied. Among the 133 known species of ariids, only eight have been karyotyped. Cytogenetic analyses performed on Genidens barbus and Sciades herzbergii revealed that both species have 2n = 56 chromosomes and Cathorops...

RESUMEN Se analizan los posibles mecanismos que permiten a una especie exótica convertirse en invasora: aumento de la variación genética, disminución de los enemigos naturales, regulación biótica, purga, mutaciones adaptativas, cambios epigenéticos. Se hace un especial énfasis a estos últimos cambios, para explicar el éxito de algunas especies exót...

Lutjanidae, commonly known as snappers, includes 105 species, grouped in four subfamilies. In spite of the high number of species and of its worldwide distribution, the family has been little investigated and the phylogenetic relationships among some of its genera and species are still cause for debate. Only a small number of the species has been c...

La introducción de organismos a un nuevo ambiente generalmente ocurre en escaso número de individuos, lo cual determina el llamado "cuello de botella", reduciendo la variación genética, mientras que la selección reduce aún más esta variación. Entonces, ¿Cómo estos exóticos son exitosos, expanden su rango de distribución bajo nuevas condiciones, evo...

Given that the introduction of organisms into a new environment usually occurs in low numbers, reducing genetic diversity (the so-called bottleneck effect), and that selection further decreases diversity beyond that caused by the bottleneck, then how do some alien species, if their genetic variation is low under new conditions, succeed in evolving...

This study reports the first description of the karyotype of Agonostomus monticola, a species belonging to a genus which is considered to be the most primitive among living mugilid fish. Specimens from Panama and Venezuela were cytogenetically analysed by conventional chromosome banding (Ag and base-specific-fluorochrome staining, C-banding) and by...

Cytogenetic analyses performed in Cephalosilurus apurensis, Microglanis aff. cottoides and Pseudopimelodus bufonius revealed that the three species have 2n = 54 chromosomes: C. apurensis presented six metacentric (M), 28 submetacentric (SM), 14 subtelolocentric (ST), and six acrocentric (A) chromosomes, while M. aff. cottoides showed 10M, 32SM, 10S...

the present study, three species of Lutjaninae, Lutjanus analis, L. griseus and L. synagris, were analyzed by conventional Giemsa staining, C-banding and silver staining, to reveal active Nucleolus Organizer Regions (NORs). Fluorescent in situ hybridization (FISH) was also applied to establish the number and location of the ribosomal gene clusters...

Mugilidae (Teleostei) includes over 70 species, and approximately 25% of them, from all over the world, have been cytogenetically analysed. Although a review on Mugilidae cytogenetics has been recently published, new additional data provided a different perspective on the cytotaxonomic relationships previously inferred and stimulated a re-visitatio...

A comparative cytogenetic and allozyme analysis of sympatric specimens of Mugil rubrioculus and M. curema from Venezuela is reported. Specimens of M. rubrioculus exhibit a 2n=48 karyotype with exclusively acrocentric (NF=48) chromosomes, one pair of NORs interstitially located on chromosome pair number 8 and constitutive heterochromatin distributed...

Se presentan los resultados del análisis comparativo citogenético y aloenzimático entre las especies simpátricas Mugil rubrioculus y M. curema de Venezuela. Los especímenes de M. rubrioculus presentan un cariotipo con 2n=48 cromosomas exclusivamente acrocéntricos (NF=48), NORs intersticiales localizados en el par cromosómico número 8 y heterocromat...

This paper describes the karyotype analysis of Haemulon aurolineatum, Haemulon bonariensis and Haemulon plumierii, by Giemsa staining, C-banding, Ag-staining and fluorescent in situ hybridization (FISH), to locate the 18S and 5S rRNA genes. Diploid modal count in the three species was 2n = 48 acrocentric elements. Except for pair 24, which exhibite...

Molecular phylogenetic studies are very scarce for the Mugilidae family; the present analysis using DNA sequences of the mitochondrial 16S rRNA and cytochrome b genes is the first study involving Brazilian mugilids. The results corroborate the monophyly of Mugil and are elucidative for the taxonomy of Brazilian mugilids. Mugil curema is clearly div...

The original description of Mugil gaimardianus has created various taxonomic problems in the past since the description is ambiguous and the type specimen is apparently lost. The name M. gaimardianus could not be reliably applied to any known species and was suppressed by the International Commission on Zoological Nomenclature (ICZN) (Bulletin of Z...

A cytogenetic study of Stephanolepis setifer by conventional Giemsa stain and localization of Nucleolus Organizer Regions (NORs) by silver staining is reported. Females possess a diploid chromosome number of 2n=34 chromosomes, all of which are acrocentric, Males exhibit a karyotype with 2n=33 chromosomes, consisting of 32 acrocentric chromosomes in...

The karyotype and chromosomal characteristics of the characid fish Triportheus venezuelensis were investigated using differential staining techniques (C-banding, Ag-NOR staining) and fluorescent in situ hybridization (FISH) with an 18S rDNA probe. The diploid chromosome number (2n = 52), karyotype composition and sex chromosome determination system...

The family Loricariidae, with about 683 species, is one the largest fish families in the world. The subfamily Hypostominae was recently reviewed and is now divided in five tribes. With the main objective of contributing to a better understanding of the relationships of the members of the subfamily Hypostominae, cytogenetic analyses were conducted i...

One of the most relevant topics in the biology of invasion concerns the genetic changes that occur subsequent to a species invasion, an issue of particular focus among conservation biologists. Colonizing a novel environment presents a genetic challenge to invading species because such species surely have not experienced the selective pressures pres...

This paper describes the karyotype of Odontesthes regia by means of Giemsa staining, C-banding, to reveal the distribution of the constitutive heterochromatin, and by Ag-staining and fluorescent in situ hybridization (FISH), to locate ribosomal genes (rDNA). The chromosome diploid modal count in the species was 2n = 48. The karyotype is composed of...