Gustavo Somoza

Gustavo Somoza
INTECH (CONICET-UNSAM)

Dr. in Biological Sciences

About

205
Publications
31,877
Reads
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5,376
Citations
Citations since 2017
60 Research Items
2384 Citations
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20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
Introduction
Gustavo Somoza currently works at the INTECH (CONICET-UNSAM) in Chascomús. Gustavo does research in Endocrinology, Evolutionary Biology and Zoology. His current projects are related to Fish reproductive physiology and sex differentiation and endocrine disruption in non-mammalian vertebrates.
Additional affiliations
February 2010 - March 2010
November 2008 - October 2019
National Scientific and Technical Research Council
Position
  • Principal Investigator
May 2006 - July 2006
Université de Rennes 1
Position
  • Professor

Publications

Publications (205)
Article
Aggression has been historically linked to males and androgen levels and, even if females from different species also display aggressive behavior, female aggression is still widely understudied. The aim of the present work is to disentangle how sex differences in social plasticity can be explained by sex steroid hormone levels, gonadal state and/or...
Article
Atrazine (ATZ) is a frequent contaminant in freshwater ecosystems within agricultural regions. The capacity of this herbicide to interfere with the vertebrate endocrine system is broadly recognized, but the mechanisms and responses usually differ among species. In this study, ATZ effects on hypothalamus-pituitary-gonadal (HPG) axis key genes expres...
Article
Full-text available
Anthropic activities can seriously affect the health of the organisms inhabiting them, and the observation of any alteration in the reproduction of fish could be associated with the presence of endocrine disruptors. In this manuscript we have collected information on the adverse effects of pollutants (heavy metals, environmental steroids, and agroc...
Article
A particularly concerning outcome of environmental pollution is the disturbance of reproductive processes. However, studies on the impacts of pollution on the reproductive health of fish inhabiting South American environments are limited. We studied the impact of anthropogenic pollution on the reproductive health of two sympatric Patagonian marine...
Article
Full-text available
In the last two decades, kisspeptin (Kiss) has been identified as an important player in the regulation of reproduction and other physiological functions in vertebrates, including several fish species. To date, two ligands (Kiss1, Kiss2) and three kisspeptin receptors (Kissr1, Kissr2, Kissr3) have been identified in teleosts, likely due to whole-ge...
Article
Full-text available
Roundup Transorb® (RDT) is a glyphosate-based herbicide commonly used in agricultural practices worldwide. This herbicide exerts negative effects on the aquatic ecosystem and affects bioenergetic and detoxification pathways, oxidative stress, and cell damage in marine organisms. These effects might also occur at the transcriptional level; however,...
Article
Full-text available
Many teleost fishes can withstand long feed deprivation periods, either due to an eventual lack of food or because of their behavior during reproduction and/or parental care. In this work, the effects of total food restriction on the oogenesis, spermatogenesis, and reproductive hormones of the neotropical cichlid fish Cichlasoma dimerus were studie...
Article
The hypothalamic-pituitary-gonadal axis is the main system that regulates reproduction in vertebrates through a complex network that involves different neuropeptides, neurotransmitters, and pituitary hormones. Considering that this axis is established early on life, the main goal of the present work is to gather information on its development and t...
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,...
Book
Full-text available
La obra es una introducción a la Ecotoxicología para estudiantes universitarios de carreras vinculadas con la Ciencias Ambientales. Se organiza en 14 capítulos que abordan desde una introducción histórica de la disciplina, luego una primera sección por los diferentes tipos de contaminantes y cómo se acumulan en los organismos vivos, seguido por una...
Article
Full-text available
• The distribution of genetic diversity across a species distribution range is rarely homogeneous, as the genetic structure among populations is related to the degree of isolation among them, such as isolation by distance, isolation by barrier, and isolation by environment. • Jenynsia lineata is a small viviparous fish that inhabits a wide range of...
Article
Full-text available
The environment experienced during development is a key factor determining intraspecific variation in postnatal growth. In sexually size‐dimorphic species, the larger sex typically grows at a higher absolute rate and consequently is more sensitive or vulnerable to restrictive environments. In addition, this sensitivity can be intrinsic when it is c...
Article
The effects of 17α-ethinylestradiol (EE2) on sex ratio, gonopodium morphology, and gonadal histology of C. decemmaculatus were assessed by a full-lifecycle exposure experiment. Newborn fish were waterborne exposed to 30, 100, and 300 ng EE2/L for 90 d, using 50 fish per treatment. Additionally, in December of 2016, a field survey was conducted on a...
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...
Article
It is well known that gonadotropin-releasing hormone (Gnrh) has a key role in reproduction by regulating the synthesis and release of gonadotropins from the anterior pituitary gland of all vertebrates. About 25 years ago, another neuropeptide, kisspeptin (Kiss1) was discovered as a metastasis suppressor of melanoma cell lines and then found to be e...
Chapter
El eje hipotálamo-hipofisario está constituido por neuronas neurosecretoras localizadas en el hipotálamo, la glándula hipófisis y las glándulas y órganos diana que se encuentran bajo su control. Debido a su estructura y función, este eje representa la conexión entre dos sistemas de control ho-meostático: el sistema nervioso y el sistema endocrino....
Article
In avian species living at high altitudes and latitudes, reproductive events are largely controlled by photoperiod, with changes being perceived mainly through encephalic photoreceptors located in the hypothalamus. It is known that during long day periods (reproductive periods), the information transmitted by brain photoreceptors triggers the produ...
Article
The vertebrate pituitary is arguably one of the most complex endocrine glands from the evolutionary, anatomical and functional perspectives. The pituitary plays a master role in endocrine physiology for the control of growth, metabolism, reproduction, water balance, and the stress response, among many other key processes. The synthesis and secretio...
Article
The first step for assessing and refining the nutritional requirements during the larval and early juvenile stages of a fish is the study of the ontogeny of digestive system functionality. The combination of these studies with ecological and anatomical knowledge of the species of interest establishes the base for facing one of the major aquaculture...
Article
Full-text available
Rivers and lake systems in the southern cone of South America have been widely influenced by historic glaciations events, carrying important implications on the evolution of aquatic organisms including prompting transitions between marine and freshwater habitats and by triggering hybridization among incipient species via waterway connectivity and s...
Article
Full-text available
Although some studies have investigated the effects of dietary l-tryptophan on agonistic behavior, research on adult fish specimens is still lacking. Moreover, submissive behaviors have been generally overlooked. We focused on agonistic behavior between males of the cichlid fish Cichlasoma dimerus, in dyadic encounters held in a novel context after...
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
The knowledge of how temperature influences elasmobranchs reproductive physiology allows a better understanding of their reproductive patterns. This study describes the relationship between temperature fluctuations and the plasmatic changes of the sex steroids related to reproduction: testosterone (T), estradiol (E2) and progesterone (P4), througho...
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
Full-text available
Gonadotropin-inhibitory hormone, GnIH, is named because of its function in birds and mammals; however, in other vertebrates this function is not yet clearly established. More than half of the vertebrate species are teleosts. This group is characterized by the 3R whole genome duplication, a fact that could have been responsible for the great phenoty...
Article
Full-text available
Olrog’s Gull (Larus atlanticus) is a vulnerable species; however, no study has addressed the relationship between body measurements and sex. To provide an easy and reliable work tool to identify the sex of individuals, adult Olrog’s Gulls (n = 111) were weighed, several measurements were taken, and the sexes were determined using DNA analyses. All...
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...
Article
Kisspeptin receptors are G-Protein-Coupled Receptors that regulate GnRH synthesis and release in vertebrates. Here, we report the gene structure of two kisspeptin receptors (kissr2 and kissr3) in pejerrey fish. Genomic analysis exposed a gene structure with 5 exons and 4 introns for kissr2 and 6 exons and 5 introns for kissr3. Two alternative varia...
Data
(A) Schematic representation of a portion of kissr2 gene in pejerrey showing the primer combinations used in this study. C1: kissr2-Ex3-4-F/kissr2-Ex4-R1, used to specifically amplify kissr2_v1, C2: kissr2-Int3-F/kissr2-Ex4-R, used to specifically amplify v2 isoform and C3: kissr2-Ex3-F/kissr2-Ex4-R, used to determine the presence of both isoforms...
Data
Homology model of the Kissr2. Pejerrey Kiss1 sequence is shown in red.
Data
Summary of alternative splicing due to intron retention and exon deletion detected in kissr3 gene of teleost fish.
Data
Reaction efficiencies slope and correlation r2 values of real-time quantitative PCR assays. The efficiency and conditions for primer sets for kiss2, lhb, and, fshb were already reported in Tovar Bohórquez et al. (29) and Elisio et al. (58).
Data
Homology model of the Kissr3. Pejerrey Kiss2 sequence is shown in red.
Data
Weblogo 3 (http://weblogo.threeplusone.com/) representation of the sequence alignments in teleost fish peptides. (A) Teleost Kiss1-15: pjKiss1-15: QDVSSYNLNSFGLRY. (B) Teleost Kiss2-12: pjKiss2-12: SKFNYNPFGLRF.
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
The endocrine system plays a crucial role in regulating the activity of cells and organs among vertebrates, including the class Chondrichthyes. Accordingly, Chondrichthyan endocrinology publications have been steadily increasing in the global literature. However, while interest in South American Chondrichthyan research has been growing over the las...
Article
Reproduction is regulated by the hypothalamic-pituitary-gonadal axis. The first neuropeptide identified that regulates this function was the decapeptide gonadotropin-releasing hormone (GnRH). Nowadays, in gnatostomates, a number of GnRH variants have been identified and classified into three different types: GnRH1, GnRH2, and GnRH3. Almost 30 years...
Article
Territorial aggression has been widely studied in males and it has been historically suggested that androgens are key mediators of this behavior. However, more recent evidence suggests that it is the aromatization to estrogens, rather than androgens themselves, that is key to regulating this behavior. Females also display aggressive behaviors, but...
Article
In the last years, the agricultural expansion has led to an increased use of pesticides, with glyphosate as the most widely used worldwide. This is also the situation in Argentina, where glyphosate formulations are the most commercialized herbicides. It is known that glyphosate formulations are much more toxic than the active ingredient, and this d...
Article
Full-text available
Olrog’s Gull (Larus atlanticus) is a vulnerable species; however, no study has addressed the relationship between body measurements and sex. To provide an easy and reliable work tool to identify the sex of individuals, adult Olrog’s Gulls (n = 111) were weighed, several measurements were taken, and the sexes were determined using DNA analyses. All...
Article
Aggression is an extremely complex behaviour and female aggression is understudied when compared to males. Despite the fact that it has been suggested that conflict among females may be more frequently resolved peacefully, in many species females show high levels of aggression. We used Cichlasoma dimerus to describe dynamics and conflict outcome in...
Data
Alignment of vertebrate GAP sequences. The alignment was performed using muscle included in SeaView (version 4.6.1) and manually adjusted. The first * indicates the position of the cysteine residue conserved in GAP2 sequences, except in mammals, in most of the teleost GAP1 sequences and in lamprey GAP-I, -II, and -III. The second * indicates the po...
Data
Vertebrate species and accession numbers of the complete prepro-GnRH sequences used to analyze GAP sequences. Lines divide the different vertebrate groups. GB. GenBank database; EN, Ensembl Genome Browser. *Sequence obtained from Ref. (68), which is not available in the data bases consulted.
Data
Tables showing the amino acid (aa) lengths of GAP1, GAP2, and GAP3 from various gnathostome species. Bold indicates the more representative length in all species analyzed.
Data
Amino acid sequence identity (I%) and similarity (S%, in bold) within each GAP type. Gray indicates those values, both identity and similarity, lower than 50%.
Article
For many species parental behavior is essential for the survival of the offspring. While the ultimate causes of teleost parental behavior have been widely studied, comparatively little is known about its proximate causes. The aim of this study was to analyze the yet unexplored, potential dual role of brain and gonadal aromatases, the enzymes respon...
Article
Full-text available
GnRH-associated peptide (GAP) is the C-terminal portion of the gonadotropin-releasing hormone (GnRH) preprohormone. Although it was reported in mammals that GAP may act as a prolactin-inhibiting factor and can be co-secreted with GnRH into the hypophyseal portal blood, GAP has been practically out of the research circuit for about 20 years. Compara...
Article
Full-text available
This study confirms the presence of two species of the non-native mosquitofish Gambusia in Argentina. The risks that they represent to native biota, their potential dispersal in the region, and their effectiveness in mosquito larvae control are discussed.
Article
Full-text available
The aim of this study was to assess the response of the gonopodium morphology, and the gonadal and liver histology of adult male Cnesterodon decemmaculatus, to sublethal long-term exposure concentrations of 17α-ethinylestradiol (EE2 ). Two experiments were conducted exposing the fish to waterborne concentrations of EE2 ranging from 20 to 200 ng/L f...
Article
Full-text available
Salinity gradients are critical habitat determinants for freshwater organisms. Silverside fishes in the genus Odontesthes have recently and repeatedly transitioned from marine to freshwater habitats, overcoming a strong ecological barrier. Genomic and transcrip-tomic changes involved in this kind of transition are only known for a few model species...
Article
In vertebrates, the reproduction is controlled by the brain-pituitary-gonadal (BPG) axis and kisspeptin has emerged as a key player of this axis. In this study, we analyzed changes in the expression levels of kiss1, kiss2, and their receptors, kissr2 and kissr3 during gametogenesis in the BPG axis of feral Odontesthes bonariensis. In females, level...
Article
Full-text available
Gonadotropin releasing hormone (GnRH) is one of the key players of brain-pituitary-gonad axis, exerting overall control over vertebrate reproduction. In zebrafish, two variants were characterized and name as Gnrh2 and Gnrh3. In this species, Gnrh3, the hypohysiotropic form, is expressed by neurons of the olfactory-retinal system, where it is relate...
Article
The enzyme aromatase, responsible for the conversion of C19 androgens to C18 estrogens, exists as two paralogue copies in teleost fish: Cyp19a1a mostly expressed in the gonads, referred as gonadal aromatase, and Cyp19a1b, mostly expressed in the brain, accordingly known as brain aromatase. The neural localization of Cyp19a1b is greatly contained wi...
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
Full-text available
We evaluated the acute lethal and sublethal effects of technical-grade glyphosate (GLY) and the GLY-based commercial formulation Roundup ULTRA MAX® (RU) on two Gosner stages (Gss) 25 and 36 of the South-American Creole frog, Leptodactylus latrans. Bioassays were performed following standardized methods within a wide range of concentrations (0.0007-...
Article
In vertebrates, kisspeptins and their receptors are known to be related to puberty onset and gonadal maturation, however, there are few studies concerning their role in early development. Here, we characterize the kisspeptin system in the pejerrey, Odontesthes bonariensis, a fish with strong temperature-dependent sex determination. We reconstructed...
Article
The role of gonadotropin-inhibitory hormone (GnIH) in the inhibition of the reproductive axis has been well-established in birds and mammals. However, its role in other vertebrates such as teleost fish remains controversial. In this context, the aim of this study was to evaluate whether GnIH modulates the release of gonadotropins and growth hormone...
Article
Knowledge of environmental influence on reproductive dynamics in chondrichthyans is critical for effective management. The present study assessed the potential influences of temperature and depth on aggregations and reproductive events of the narrownose smooth-hound shark (Mustelus schmitti), using an analysis criterion based on the co-occurrence o...
Article
In some reptiles, gonadal outcome is regulated by temperature during a critical period of the embryonic development. Gonadal steroid hormones are seen as effectors of the gonadal differentiation process. Recently, stress and glucocorticoids (GCs), stress-related hormones in vertebrates, have been considered as potential modulators of the sex determ...
Article
The temperature-sensitive period is the time during development during which sex determination occurs in vertebrates that undergo temperature-dependent sex determination, such as in caimans. The interplay among temperature and steroid hormones is also known, and it has been suggested that stress hormones (corticosterone) might influence sex ratios...
Article
Social animals with hierarchal dominance systems are particularly susceptible to their social environment. There, interactions with conspecifics and hierarchal position can greatly affect an individual's behavior, physiology and reproductive success. Our experimental model, Cichlasoma dimerus, is a serially-monogamous Neotropical cichlid fish with...
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
Concentrations of estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) were investigated for the first time in sewage effluents and receiving waters of the "Río de la Plata" estuary and neighboring areas by means of LC-MS/MS. E2 and EE2 were ubiquitous in the evaluated sewage effluent samples showing concentrations ranging between 122-63...
Conference Paper
The temperature-sensitive period is the time during development at which sex determination occurs in temperature-dependent sex determination vertebrates, such as in caimans. The interplay among temperature and steroid hormones is also known, and that stress hormones (corticosterone) can influence sex ratios in some reptiles. To explore this, we mea...
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
Full-text available
Prochilodus lineatus is a highly migratory fish species that sustains the most important commercial fishery of Paraná-Paraguay basin. Migratory patterns are poorly known and only few population genetic studies are available for this species in the Upper Paraná. To assess genetic population structure, we genotyped a sample of 93 individuals from the...
Article
Full-text available
Background/aims: Adult mice lacking functional GABAB receptors (GABAB1KO) show altered Gnrh1 and Gad1 expressions in the preoptic area-anterior hypothalamus (POA-AH) and females display disruption of cyclicity and fertility. Here we addressed whether sexual differentiation of the brain and the proper wiring of the GnRH and kisspeptin systems were...
Article
In non-mammalian vertebrates, serotonin (5-HT)-producing neurons exist in the paraventricular organ (PVO), a diencephalic structure containing cerebrospinal fluid (CSF)-contacting neurons exhibiting 5-HT or dopamine (DA) immunoreactivity. Because the brain of the adult teleost is known for its neurogenic activity supported, for a large part, by rad...
Data
Full-text available
Juvenis de pejerrey, Odontesthes bonariensis, foram expostos a Vermelho de Alizarina S (ARS) 0,1% de duas formas, sozinho ou com uma imersão anterior em 2,2% de solução salina (Indução osmótica, IO) para melhorar o método de marcação ARS. Os procedimentos foram realizados no campo e os peixes foram liberados em gaiolas (tanques-rede) de 1 m3 na lag...