Análisis de la relación huésped-patógeno en el sistema Calomys-Virus Junín

Fil: Vitullo, Alfredo Daniel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Myelin Basic Protein and a Multiple Sclerosis-related MBP-peptide Bind to Oligonucleotides

Aptamer ligands for myelin basic protein (MBP) were obtained using the systematic evolution of ligand by exponential enrichment (SELEX) method. Two clones were isolated from a pool of oligonucleotides and tested for MBP targeting. Using purified MBP, we demonstrated the binding activity of the aptamers and we also showed the affinity of MBP for oligonucleotides of specific length. Moreover, one selected aptamer competitively inhibited the binding of an MBP-specific antibody to MBP and the aptamer was found more sensitive than a commercial antibody. In addition, we showed the ability of the aptamer to detect myelin-rich regions in paraffin-embedded mouse brain tissue. Therefore, the MBP-binding activity of the selected oligonucleotide may prove useful as a tool for life science and medical research for myelin detection and might be a good lead for testing it in autoimmune diseases such as multiple sclerosis.Fil: Rozenblum, Tomas Guido. Universidad Maimonides. Facultad de Ciencias de la Salud; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kaufman, Tomás. Universidad Maimonides. Facultad de Ciencias de la Salud; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vitullo, Alfredo Daniel. Universidad Maimonides. Facultad de Ciencias de la Salud; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The balance between apoptosis and autophagy regulates testis regression and recrudescence in the seasonal-breeding South American plains vizcacha, Lagostomus maximus

Mammalian testis undergoes deep changes in their architecture and function during photoregression conditions in seasonal breeders. Particularly, the testicular mechanisms that regulate the transition between the active (functional) and inactive (regression) stage vary between species. The aim of the present study was to analyze the incidence of proliferation, apoptosis and autophagy in the testicular seminiferous ephitelium of a seasonal breeder, Lagostomus maximus, during the annual reproductive cycle. We observed that proliferating spermatogonia increased from the active testis until reaching the maximum peak in the activating testis. During the annual reproductive cycle, the quantity of apoptotic-TUNEL positive spermatogonia and meiotic germ cells was constant and this might be regulated by the members of the BCL2 family. Only in the activating testis, apoptosis of germ cells was almost undetectable. The analysis of the autophagic-related proteins BECN1 and LC3 showed their localization in Leydig cells and the germ cells in the active and activating testis. In the inactive testis, BECN1 and LC3 ceased to be immunolocalized within the seminiferous tubules and the mRNA expression of both regulators decreased. Moreover, the expression of BECN1 and LC3 and also the apoptotic index were up regulated in testicular cultures subjected to nutritional stress. These results suggest a possible interaction between apoptosis and autophagy in the active and activating testis (characterized by high metabolic requirement and nutrient), where autophagy could promote survival over cell death. In the inactive testis, the absence of autophagic-related proteins might explain the massive loss of germ cells, suggesting that autophagy plays new and key role in the alterations of the seminiferous epithelium during photoregression.Fil: Gonzalez, Candela Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas; ArgentinaFil: Muscarsel Isla, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas; ArgentinaFil: Vitullo, Alfredo Daniel. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The developing ovary of the South American plains vizcacha, Lagostomus maximus (Mammalia, Rodentia): Massive proliferation with no sign of apoptosis-mediated germ cell attrition

Apoptosis-dependent massive germ cell death is considered a constitutive trait of the developing mammalian ovary that eliminates 65-85% of the germinal tissue depending on the species. After birth and during adult lifetime, apoptotic activity moves from the germ cell proper to the somatic compartment, decimating germ cells through follicular atresia until the oocyte reserve is exhausted. In contrast, the South American rodent Lagostomus maximus shows suppressed apoptosis-dependent follicular atresia in the adult ovary, with continuous folliculogenesis and massive polyovulation, which finally exhausts the oocyte pool. The absence of follicular atresia in adult L. maximus might arise from a failure to move apoptosis from the germinal stratum to the somatic compartment after birth or being a constitutive trait of the ovarian tissue with no massive germ cell degeneration in the developing ovary. We tested these possibilities by analysing oogenesis, expression of germ cell-specific VASA protein, apoptotic proteins BCL2 and BAX, and DNA fragmentation by TUNEL assay in the developing ovary of L. maximus. Immunolabelling for VASA revealed a massive and widespread colonisation of the ovary and proliferation of germ cells organised in nests that disappeared at late development when folliculogenesis began. No sign of germ cell attrition was found at any time point. BCL2 remained positive throughout oogenesis, whereas BAXwas slightly detected in early development. TUNEL assay was conspicuously negative throughout the development. These results advocate for an unrestricted proliferation of germ cells, without apoptosis-driven elimination, as a constitutive trait of L. maximus ovary as opposed to what is normally found in the developing mammalian ovary.Fil: Leopardo, Noelia Paola. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jensen, Cristian Federico. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Willis, Miguel Alfredo. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Espinosa, Maria Beatriz. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vitullo, Alfredo Daniel. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Cocaine alters mouse germ cells epigenome with direct impact on h4ac expression and dna methylation in the sperm

Cocaine intake is associated with testicular toxicity and significantreproductive function impairment. There is accumulating evidencethat cocaine administration can trigger nongenetic inheritancethrough the male germ line affecting development and behavior ofthe offspring. The influence of environmental factors on the epigenomeof male germ cells appears to be most impactful if it happensduring a developmental phase when these cells are epigeneticallyreprogrammed. In the present study, we measured epigenetic marksin isolated germ cells of adult mice treated with cocaine (10 mg/kg) or vehicle, in an intermittent binge protocol (3 i.p. injections, 1h apart, one day on/off for 13 days). We found that chronic cocaineintake disrupts male germ cell epigenetic homeostasis, increasingglobal methylated citocine (5-mC) levels in DNA from germ cells andcauda epididymal sperm (germ cells: vehicle 13.15 ± 0.99 vs cocaine20.113 ± 2.28; sperm: vehicle 15.81 ± 1.08 vs cocaine 21.35± 1.52). Cocaine also increased acetylated histone 4 (H4ac) proteinlevels and decreased class I deacetylases HDAC1/2 mRNA andprotein expression (p<0.05). The mRNA expression levels of classIIa and IIb HDACs were also altered (p<0.05). Immunolocalizationstudies showed that HDAC1/2 were mainly expressed in primaryspermatocytes and H4ac was immunolocalized in late meiotic stagesin vehicle mice while it was detected in primary spermatocytesand in successive stages until round spermatid in cocaine-treatedmice. We observed altered mRNA expression of DNA methylationmarkers in isolated germ cells showing decreased levels of Dnmt3band Tet1 gene expression after cocaine treatment (p<0.05). TET1was mainly immunolocalized in primary spermatocytes in vehicleand cocaine-treated mice. The results presented here broaden thebasic knowledge of the impact of addictive stimulants on testicularpathophysiology, fertility and male reproductive health and implythat altered epigenetic homeostasis by cocaine may have potentialconsequences on future generations.Fil: Gonzalez, Betina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Gambini Pantoja, Camilo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Vitullo, Alfredo Daniel. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bisagno, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Gonzalez, Candela Rocio. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaLXIII Reunión Anual de la Sociedad Argentina de Investigación Clínica, LXVI Reunión Anual de la Sociedad Argentina de Inmunología y Reunión Anual de la Asociación Argentina de FisiologíaMar del PlataArgentinaSociedad Argentina de Investigación ClínicaSociedad Argentina de InmunologíaAsociación Argentina de FisiologíaAsociación Argentina de VirologíaAsociación Argentina de Nanomedicina

Inmunolocalización del sistema TGFB1 en fibrosis de la glándula submandibular bajo periodontitis experimental en ratas

La saliva es la primera barrera para la entrada de bacterias y virus en el cuerpo. Las glándulas submandibulares (GSM) contribuyen al mantenimiento de la salud oral y a la regulación de las respuestas inmunoinflamatorias. Estudios previos sugieren que el factor de crecimiento transformante beta 1 (TGFB1) puede contribuir a la fibrosis de las glándulas salivales, pero la expresión y localización del sistema TGFB1 en las GSM no ha sido dilucidada. El objetivo del presente trabajo fue analizar por inmunohistoquímica en las GSM de ratas la expresión de TGFB1 y sus receptores específicos ALK5 (profibrótico) y ALK1 (proproliferativo) y el coreceptor endoglina (EDG) en un modelo de periodontitis bilateral experimental (PE) (hilo de algodón alrededor del cuello de los primeros molares inferiores) durante 1 y 6 semanas. Las GSM fueron fijadas y embebidas en parafina para realizar cortes seriados los cuales se tiñeron con hematoxilinaeosina para analizar la histología o se procesaron para realizar la técnica de inmunohistoquímica mediante detección con diaminobenzidine. La histología de las GSM de animales con PE reveló cambios estructurales tiempo dependientes, con una marcada reducción de la altura de los conductos, destrucción celular, pérdida de gránulos secretores, congestión periductal y exceso de tejido conectivo que rodea los conductos, indicando un proceso de fibrosis respecto de las GSM de animales control. TGFB1, ALK5 y ALK1 y el coreceptor EDG fueron principalmente inmunolocalizados en las células que forman los ductos y en las áreas de fibrosis en los grupos con PE. La expresión del receptor profibrótico ALK5 se incrementó en las áreas de fibrosis en GSM de animales con PE. En GSM de ratas con PE, la localización de los receptores específicos de TGFB1 en las células de los conductos y áreas de fibrosis, junto con la expresión de TGFB1 en las áreas circundantes, podría indicar acciones paracrinas y autocrinas ejercidas por TGFB1 a través de sus receptores específicos. Los resultados de este estudio sugieren que TGFB1 podría inducir un proceso de fibrosis promoviendo la proliferación celular a través de los receptores ALK1 y EDG, y favoreciendo procesos relacionados con la fibrosis a través de su receptor ALK5, lo que conduciría a una actividad secretora anormal de la GSM durante la enfermedad periodontal.Saliva is the first barrier to entry of bacteria and viruses into the body. The submandibular glands (SMG) contribute to the maintenance of oral health and regulation of immune/ inflam matory responses. Previous studies suggest that transforming growth factor beta 1 (TGFB1) may contribute to salivary gland fibrosis but the expression of the TGFB1 system in the SMG has not been elucidated. Thus, the aim of this study was to analyze in rat SMG the immunolocalization of TGFB1 and its specific receptors ALK5 (profibrotic) and ALK1 (proproliferative) and the coreceptor endoglin (EDG) in a bilateral experimental periodontitis (EP) model (cotton thread ligature around the neck of the first lower molars) for 1 and 6 weeks. Fixed SMG were embedded in paraffin and serially cut for routine hematoxylin–eosin staining for histological analysis or immunohistochemical techniques by diaminobenzidine detection. SMG histology from animals with EP showed timedependent structural changes involving marked reduction in the height of the contoured ducts, cell destruction, loss of secretory granules, periductal congestion and excess connective tissue surrounding these ducts indicative of a fibrotic process, compared to control SMG. TGFB1, ALK5 and ALK1 receptors and the coreceptor EDG were mainly immunolocalized in ductal cells and in the fibrotic areas in EP groups. The expression of the profibrotic ALK5 receptor was increased in areas of fibrosis in SMG of animals with EP. In SMG of rats with EP, the localization of the TGFB1 specific receptors in the ducts and cells from fibrotic areas, due to the expression of TGFB1 in the surrounding areas, might indicate paracrine and autocrine actions exerted by TGFB1 via its specific receptors. The results of this study suggest that TGFB1 promotes fibrosis, inducing cell proliferation via ALK1 and EDG receptors and stimulates fibrosis relatedprocesses via ALK5 receptor, which could lead to abnormal secretor activity of the SMG during periodontal disease.Fil: Gonzalez, Candela Rocio. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico. Departamento de Estudios Biomédicos y Biotecnológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Amer, Mariano. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Vitullo, Alfredo Daniel. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico. Departamento de Estudios Biomédicos y Biotecnológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gonzalez Calvar, Silvia I.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Vacas, María I.. Hospital Italiano. Instituto Universitario - Escuela de Medicina; Argentin

A dual death/survival role of autophagy in the adult ovary of Lagostomus maximus (Mammalia- Rodentia)

Follicular atresia is a cell death event that occurs in the great majority of follicles before ovulation in the mature mammalian ovary. Germ cell loss has been mainly associated to apoptosis although autophagy also seems to be at play. Aimed to increase our understanding on the possible cooperating role of autophagy and apoptosis in follicular atresia and/or follicular survival, we analyzed both programmed cell death mechanisms in a rodent model, the South American plains vizcacha, Lagostomus maximus. Female vizcacha shows highly suppressed apoptosis-dependent follicular atresia in the adult ovary, with continuous folliculogenesis and massive polyovulation. This strategy of massive ovulation requires a permanent remodeling of the ovarian architecture to maintain the availability of quiescent primordial follicles throughout the individual's reproductive lifespan. We report here our analysis of autophagy (BECN1, LAMP1 and LC3B-I/II) and apoptosis (BCL2 and ACTIVE CASPASE- 3) markers which revealed interactive behaviors between both processes, with autophagy promoting survival or cell death depending on the ovarian structure. Strong BECN1, LC3B-II and LAMP1 staining was observed in atretic follicles and degenerating corpora lutea that also expressed nuclear ACTIVE CASPASE-3. Healthy follicles showed a slight expression of autophagy proteins but a strong expression of BCL2 and no detectable ACTIVE CASPASE-3. Transmission electron microscopy revealed a high formation of autophagosomes, autolysosomes and lysosomes in atretic follicles and degenerating corpora lutea and a low number of autophagic vesicles in normal follicles. The co-expression of LC3B-BECN1, LC3B-LAMP1 and LC3B-ACTIVE CASPASE-3 was only detected in atretic follicles and degenerating corpora lutea, while co-expression of BCL2-BECN1 was only observed in normal follicles. We propose that autophagy could act as a mechanism to eliminate altered follicles and remnant corpora lutea providing the necessary space for maturation of primordial follicles that continuously enter the growing follicular pool to sustain massive ovulation.Fil: Leopardo, Noelia Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Velazquez, Mariela Edith. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Cortasa, Santiago Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Gonzalez, Candela Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Vitullo, Alfredo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentin

The South American Plains Vizcacha, Lagostomus maximus, as a Valuable Animal Model for Reproductive Studies

The vast majority of our understanding of the mammalianreproductive biology comes from investigations mainlyperformed in mice, rats and humans. However, evidencegathered from non-conventional laboratory models, farm andwild animals strongly suggests that reproductive mechanismsshow a plethora of different strategies among species. Forinstance, studies developed in unconventional rodents suchas guinea pigs and hamsters, that share with humans someendocrine and reproductive characters, have contributed to abetter understanding of human physiology and disease [1,2]. Abetter knowledge on the variety of mechanisms that regulatereproduction could lead to improve early diagnosis, treatment,or novel strategies development to ameliorate fertility andguarantee a successful reproduction. In this letter, we brieflyintroduce Lagostomus maximus, an unconventional rodentwhose neuro-endocrinology and reproduction in general haveattracted significant interest in recent years in view of its unusualreproductive traits.Fil: Dorfman, Verónica Berta. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Inserra, Pablo Ignacio Felipe. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Leopardo, Noelia Paola. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Halperin, Julia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Vitullo, Alfredo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentin

The ovarian germinal reserve and apoptosis-related proteins in the infant and adolescent human ovary

Background: Normal pubertal ovary displays all stages of follicular development and a biased BAX/BCL2 protein ratio in favor of pro-apoptotic BAX protein comparable to the adult ovary. However, adolescents suffering malignant extragonadal disease show a limited follicle development after cytotoxic drug treatment and a reduced capacity of in vitro follicle growth. We evaluated the expression of pro- and anti-apoptotic members of the BCL2 gene family, the FAS/ FAS-L proteins from the extrinsic apoptosis pathway, the germ-cell-specific marker VASA, the pluripotency marker OCT3/4, and markers of early and late apoptosis in the ovary of pubertal patients with malignant extra-gonadal disease, which received or not pre-surgery chemotherapy, entering a cryopreservation program. Results: Ovarian biopsies from 12 adolescent girls were screened for follicle count and expression of VASA, OCT3/4, BAX, BCL2, MCL1L and S, cleaved-BID, FAS/FAS-L and CASPASE 3 through immunohistochemistry, western blot and RTPCR. All stages of folliculogenesis, from primordial to antral follicle, were present in all 12 patients analyzed. VASA and most of the screened apoptosis-related genes showed a pattern of immune-expression comparable to that previously reported. OCT3/4 showed a cytoplasmic localization in the great majority of the primordial follicles; however, in some cases the localization was nuclear. In addition, OCT3/4B showed a significant reduction compared to OCT3/4A. Unexpectedly, BCL2 was detected at all stages of folliculogenesis, associated to the Balbiani’s body in the primordial follicles, regardless of whether patients had or had not received chemotherapy, ruling out the possibility that its expression is a protective response to chemotherapy. Conclusions: These findings reveal new information on the morphological status of the follicular reserve and the expression of apoptosis-related genes in histologically normal adolescent ovary from patients undergoing extragonadal cancer. The unexpected expression of apoptosis-inhibiting BCL2 protein, both in patients that had or had not received chemotherapy, opens a new avenue for thorough investigations. Moreover, the nuclear localization of OCT3/4 protein in primordial follicle-enclosed oocytes suggests a possible increased activity of ovarian stem cells in response to chemotherapy and/or extragonadal cancer. This new information can be essential for a better managing of in vitro culture of follicles that can be removed by filtration from preserved ovarian tissue, especially in girls that entered a cryopreservation program.Fil: Albamonte, María Itatí. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Albamonte, Mirta Susana. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Bou Khair, Ricardo M.. Hospital de Niños “Dr. Ricardo Gutiérrez”. Servicio de Ginecología Infantil; ArgentinaFil: Zuccardi, Luis. Hospital de Niños “Dr. Ricardo Gutiérrez”. Servicio de Ginecología Infantil; ArgentinaFil: Vitullo, Alfredo Daniel. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Unexpected low genetic variation in the South American hystricognath rodent Lagostomus maximus (Rodentia: Chinchillidae)

The South American plains vizcacha, Lagostomus maximus inhabits primarily the Pampean and adjoining Espinal, Monte and Chaquenean regions of Argentina. In order to study the population genetic structure of L. maximus, a fragment of 560 bp of the mitochondrial DNA hypervariable region 1from 90 individuals collected from the 3 subspecies and 8 groups along Argentina was amplified and analyzed. We found 9 haplotypes. The haplotype network did not show an apparent phylogeographical signal. Although low levels of genetic variation were found in all the subspecies and groups analyzed, a radiation of L. maximus would have occurred from the North and Center of the Pampean region toward the rest of its geographic range in Argentina. Low levels of genetic diversity, the existence of a single genetically distinct population in Argentina and changes of its effective size indicate that metapopulation processes and changes in human population dynamics during the late-Holocene were important factors shaping the population genetic structure of L. maximus in Argentina.Fil: Gariboldi, María Constanza. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Inserra, Pablo Ignacio Felipe. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Lucero, Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Failla, Mauricio. No especifíca;Fil: Perez, Sergio Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Antropología; ArgentinaFil: Vitullo, Alfredo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; Argentin