Juan Fernandino

Juan Fernandino
National University of General San Martín | UNSAM · Instituto de Investigaciones Biotecnológicas (IIB-INTECH)

Ph.D. on Molecular Biology and Biotechnology

About

52
Publications
11,675
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Introduction
Juan Fernandino currently works at the Instituto Tecnológico de Chascomus (INTECH), National University of San Martín. Their current project is 'Fish reproductive physiology'.
Additional affiliations
January 2004 - December 2012
Instituto de Investigaciones BiotInstituto Tecnológico de Chascomúsecnológicas- Instituto Tecnológico de Chascomús
Position
  • Instituto de Investigaciones Biotenológicas- Instituto Tecnológico de Chascomús

Publications

Publications (52)
Article
Over the past century, evidence has emerged that endocrine disrupting chemicals (EDCs) have an impact on reproductive health. An increased frequency of reproductive disorders has been observed worldwide in both wildlife and humans that is correlated with accidental exposures to EDCs and their increased production. Epidemiological and experimental s...
Article
Full-text available
The complete mitochondrial genome of the fine flounder Paralichthys adspersus, was determined for the first time through Next Generation Sequencing (NGS) approach. The mitogenome (GenBank accession no. MW288827) has 17,060 bp in length and consisted of the well-known 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and the control region. Th...
Article
Full-text available
The exposure of adult fish to warm or high temperatures is known to impair reproduction, yet the long-term reproductive impacts for treatments at early life are not well clarified. This study aimed to evaluate the effects of warm temperature (WT) during juvenile stage on gonad maturation, gamete quality, and offspring thermotolerance in rainbow tro...
Article
A. gigas, one of the largest freshwater fish in the world, is suffering from high fishing pressure and habitat loss, which threaten the conservation status of its natural populations. Of great cultural importance to Amazonian people, the paiche or pirarucu A. gigas is in high demand for its meat, ornamental uses and other byproducts such as scales....
Preprint
Environmentally favorable conditions the sustainability of spermatogenesis is brought about by a balance between two types of division, the self-renewal division for the maintenance of the stem cell pool and the differentiation division for continuous production of spermatozoa. The production of gametes under unfavorable, stressful conditions can d...
Article
Full-text available
Atheriniform fishes have recently emerged as attractive models for evolutionary, ecological, and molecular/physiological studies on sex determination. Many species in this group have marked temperature-dependent sex determination (TSD) and yet many species also have a sex determinant gene that provides a strong drive for male differentiation. Thus,...
Article
Full-text available
The production of an adequate number of gametes is necessary for normal reproduction, for which the regulation of proliferation from early gonadal development to adulthood is key in both sexes. Cystic proliferation of germline stem cells is an especially important step prior to the beginning of meiosis; however, the molecular regulators of this pro...
Preprint
Full-text available
Arapaima gigas , one of the largest freshwater fish in the world, is suffering from high fishing pressure and habitat loss, which threaten the conservation status of its natural populations. Of great cultural importance to Amazonian people, the paiche or pirarucu A. gigas is in high demand for its meat, ornamental uses and other byproducts such as...
Preprint
Full-text available
The exposure of adult fish to warm or high temperatures is known to impair reproduction, yet the long-term reproductive impacts for treatments at early life are not well clarified. This study aimed to evaluate the effects of warm temperature (WT) during juvenile stage on gonad maturation, gamete quality, and offspring thermotolerance in rainbow tro...
Article
Morphological background adaptation is both an endocrine and a nervous response, involving changes in the amount of chromatophores and pigment concentration. However, whether this adaptation takes place at early developmental stages is largely unknown. Somatolactin (Sl) is a pituitary hormone present in fish, which has been associated to skin pigme...
Article
Full-text available
The determination of sex is an important hallmark in the life cycle of organisms, in which the fate of gonads and then the individual sex are defined. In gonochoristic teleost fish, this process is characterized by a high plasticity, considering that in spite of genotypic sex many environmental factors can cause shifts from one to another molecular...
Preprint
Full-text available
The production of an adequate number of gametes in both sexes is necessary for normal reproduction, for which the regulation of proliferation from early gonadal development to adulthood is key. Cystic proliferation of embryonic stem germ cells prior the onset of gametogenesis is an especially important step prior to the beginning of meiosis. Howeve...
Article
Full-text available
Fish present remarkable malleability regarding gonadal sex fate. This phenotypic plasticity enables an organism to adapt changes in the environment by responding with different phenotypes. The gonad and the brain present this extraordinary plasticity. These organs are involved in the response to environmental stressors to direct the gonadal fate, i...
Article
The understanding of the molecular and endocrine mechanisms behind environmentally-induced sex reversal in fish is of great importance in the context of predicting the potential effects of climate change, especially increasing temperature. Here, we demonstrate the global effects of high temperature on genome-wide transcription in medaka (Oryzias la...
Article
In a recent paper, Dahlke et al. 2020 (1) highlighted how crucial it is to consider the different stages of the life cycle to accurately model how fish respond to global warming. While we agree with this view, we argue that predictive population dynamic models should also consider an overlooked characteristic of many fishes: their sex determination...
Article
Natural and synthetic steroid hormones, excreted by humans and farmed animals, have been considered as important sources of environmental endocrine disruptors. A suite of estrogens, androgens and progestogens was measured in the wastewater treatment plant outfall (WWTPO) of Chascomús city (Buenos Aires province, Argentina), and receiving waters loc...
Preprint
Full-text available
Morphological background adaptation is both an endocrine and a nervous response, involving changes in the amount and shape of chromatophores. However, if this adaptation takes place at early developmental stages is largely unknown. Somatolactin (SL) is a pituitary hormone present in fish, which has been associated to skin pigmentation. Moreover, gr...
Article
Full-text available
Sex-determining genes have been successively isolated in several teleosts. In Odontesthes hatcheri and O. bonariensis, the amhy gene has been identified as a master sex-determining gene. However, whether this gene is conserved along related species is still unknown. In this study, the presence of amhy and its association with phenotypic sex was ana...
Article
Exposure to environmental stressors, such as high temperature (HT), during early development of fish induces sex reversal of genotypic females. Nevertheless, the involvement of the brain in this process is not well clarified. In the present work, we investigated the mRNA levels of corticotropin-releasing hormone b (crhb) and its receptors (crhr1 an...
Article
In the present study, we determined the hepatopancratic shbg transcript abundance and ovarian immunoreactive Shbg (ir-Shbg) localization in pejerrey females at different gonadal stages during an annual ovarian cycle. In the hepatopancreas, shbg expression remains was constant in pre-vitellogenic stages, decreased at final vitellogenesis to increase...
Preprint
Exposure to environmental stressors during early development has important implications for rescheduling many cellular and molecular mechanisms. In some fish species, environmental stressors, like high temperatures (HT), cause an increase in cortisol levels. In turn, this mechanism induces sex reversal of genotypic females, overriding genetic facto...
Article
Folate deficiency has been known to contribute to neural tube and neural crest defects, but why these tissues are particularly affected, and which are the molecular mechanisms involved in those abnormalities are important human health questions that remain unanswered. Here we study the function of two of the main folate transporters, FolR1 and Rfc1...
Article
Full-text available
The high biodiversity of fish in the Neotropical region contrasts with scarce or biased studies on the mechanisms involved in the sex determination in members of this fauna. In this review, we attempted to compile the information available on determination, differentiation, and manipulation of sex for Neotropical species, with special focus on silv...
Article
Sex hormone binding globulin (Shbg) is a plasma glycoprotein that binds and transports steroids in the blood of all vertebrate classes apart from birds. In the present study we characterized shbg from pejerrey, a fish species with a well characterized temperature-dependent sex determination. The pejerrey shbg mRNA comprises 1185 bp encoding for a 3...
Article
The sex of the offspring is the result of a unique process leading, in a binary fate, to the development of male or female characteristics. In this context, the aim of the present work is to present atherinopsid fish as excellent models to study sex determination. Here we present two atherinopsid fish from South America; one species, Odontesthes bo...
Article
Full-text available
Besides the well-known function of thyroid hormones (THs) for regulating metabolism, it has recently been discovered that THs are also involved in testicular development in mammalian and non-mammalian species. THs, in combination with follicle stimulating hormone, lead to androgen synthesis in Danio rerio, which results in the onset of spermatogene...
Article
AbsTrAcT. -the pejerrey Odontesthes bonariensis is a teleost with a strong temperature-dependent sex determination system (tSd). Dmrt1 and Cyp19A1 genes have been implicated in the sex differentiation process in fish, but little is known about their behavior in tSd species. In this context the expression pattern of both genes was studied during sex...
Article
Thyroid hormones (THs) exert a broad range of effects on development in vertebrate species, demonstrating connections in nearly every biological endocrine system. In particular, studies have shown that THs play a role in sexual differentiation and gonadal development in mammalian and non-mammalian species. There is considerable evidence that the ef...
Article
The development of a functional gonad implies consequences not only for the phenotypic sex but also for the reproductive capacity during adulthood. In recent years, atherinopsid fish have been extensively studied because they present a variety of and sometimes contrasting mechanisms of sex determination/differentiation. In the present work we revie...
Article
In many ectotherm species the gonadal fate is modulated by temperature early in life [temperature-dependent sex determination (TSD)] but the transducer mechanism between temperature and gonadal differentiation is still elusive. We have recently shown that cortisol, the glucocorticoid stress-related hormone in vertebrates, is involved in the TSD pro...
Article
Full-text available
In pejerrey (Odontesthes bonariensis), ovarian differentiation has been associated with gonadal aromatase expression. It is also known that exposure of pejerrey larvae to estradiol (E(2)) produces all female populations. During the last few years, the presence of ethinylestradiol (EE(2)), a synthetic E(2) analogue, has been reported in water reserv...
Article
Gonadal sex determination in vertebrates generally follows a sequence of genetically programmed events. In what is seemingly becoming a pattern, all confirmed or current candidate "master" sex-determining genes reported in this group, e.g., SRY in eutherian mammals, DMY/dmrt1bY in medaka, DM-W in the African clawed frog, and DMRT1 in chicken encode...
Article
It has been traditionally accepted that the gonadotropins (GtHs), follicle stimulating hormone (FSH) and luteinizing hormone (LH), are synthesized and secreted only by the pituitary. However, the presence of theses hormones in extrapituitary tissues has been demonstrated in mammals, and more recently also in fish. In this study, we cloned the cDNAs...
Article
Full-text available
The process of morphological development of a differentiated gonad from an undifferentiated primordium is a very important step of gonadogenesis. Studies on sexually dimorphic gene expression are important to increase our understanding of this process and to investigate how environmental factors such as temperature can regulate gonadal development....
Article
In this study, we cloned and characterized the follicle stimulating hormone receptor (Fshr) and luteinizing hormone receptor (Lhr) cDNAs of pejerrey Odontesthes bonariensis, a species with temperature-dependent sex determination (TSD), and analyzed their expression in relation to Fshb and Lhb subunits during gonadogenesis at temperatures producing...
Article
Sex steroids are known to be involved in gonadal differentiation in fish, but whether androgens are early mediators of testis differentiation remains unclear. We studied the sex-related developmental variations in the gene expression of two key enzymes involved in steroids and androgen synthesis (cyp11a1 and cyp11b1) in trunks and isolated gonads o...
Article
Full-text available
Gonadal fate in many reptiles, fish, and amphibians is modulated by the temperature experienced during a critical period early in life (temperature-dependent sex determination; TSD). Several molecular processes involved in TSD have been described but how the animals "sense" environmental temperature remains unknown. We examined whether the stress-r...
Article
Pejerrey is a teleost fish presenting a strong temperature-dependent sex determination. This study was conducted to clone pejerrey amh cDNA, analyze its expression profile during thermal and endocrine manipulation of gonadal differentiation, and compare its expression with that of gonadal aromatase (cyp19a1). Amh displayed higher expression at masc...
Article
Although estrogens exert many functions on vertebrate brains, there is little information on the relationship between brain aromatase and estrogen receptors. Here, we report the cloning and characterization of two estrogen receptors, alpha and beta, in pejerrey. Both receptors' mRNAs largely overlap and were predominantly expressed in the brain, pi...
Conference Paper
Full-text available
The pejerrey Odontesthes bonariensis is a teleost with a strong temperature-dependent sex determination system (TSD). Dmrt1 and cyp19a1 genes have been implicated in the sex differentiation process in fish, but little is known about their behavior in TSD species. In this context the expression pattern of both genes was studied during sex differenti...
Conference Paper
Full-text available
The present work shows that brain aromatase gene expression during the period of sex determination/differentiation was significantly enhanced in pejerrey larvae at masculinizing (29°C, MPT) compared to feminizing (17°C, FPT) temperatures. Analysis by immunocytochemistry (ICC) showed that aromatase expressing cells were evidenced first in the pituit...
Conference Paper
Full-text available
Four genes related to the process of sex differentiation were cloned and their expression analyzed during gonadal differentiation of Odontesthes hatcheri, SF1, P450aro and AMH presented one single copy whereas DMRT1 presented three isoforms. Among the four genes, clear sexually dimorphic expression was observed for P450arom and AMH, with increased...
Article
Full-text available
The pejerrey (Odontesthes bonariensis) is a teleost fish with strong temperature-dependent sex determination (TSD). Several studies have shown that dmrt1 and gonadal aromatase (cyp19a1) are implicated in the sex differentiation process in teleosts but little is known on the expression balance and endocrine regulation of these two genes during TSD....
Article
Cytochrome P450 aromatase (cyp19) is an enzyme that catalyzes the conversion of androgens to estrogens and may play a role in temperature-dependent sex determination (TSD) of reptiles, amphibians, and fishes. In this study, the ovarian P450 aromatase form (cyp19A1) of pejerrey Odontesthes bonariensis, a teleost with marked TSD, was cloned and its e...
Article
Most vertebrates express two gonadotropin releasing hormone (GnRH) variants in brain tissue but there is an increasing number of fish species for which a third GnRH form has been detected. We characterized the precursors (cDNAs) of all three forms expressed in the brain of the pejerrey (silverside) fish, Odontesthes bonariensis (Atheriniformes): ty...
Article
Dmrt1, a putative transcription factor with a DM-binding motif (called the DM domain), is generally considered to be exclusively expressed in testicular tissue, except in some teleost species where it has also been demonstrated to be expressed at the ovary. The aim of the present manuscript was to characterize the dmrt1 cDNA and analyze its express...
Article
Three different genes known to be involved in the mammalian sex-determining pathway, SOX9, DMRT1 and SF1, were characterized in a remarkable temperature sex determining species, the pejerrey Odontesthes bonariensis.

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Projects (2)
Project
To study the effects of global warming on the sexual fate and reproductive parameters of various fish species of aquaculture interest through molecular and physiological techniques to improve their management under farming conditions.