Empresarios, convertibilidad y crisis. ¿Entre la dolarización y la devaluación?; Entrepreneurs, Convertibility, and Crisis: Between Dollarization and Devaluation? Salvia, Sebastian Pedro Revista indizada en: Red ALyC / Biblioteca Virtual de CLACSO / CLASE, Citas Latinoamericanas en Ciencias Sociales UNAM, México / Directory of Open Access Journals (DOAJ) / e-Revistas, Fuente Académica / HAPI, Hispanic American Periodical Index UCLA, Estados Unidos / Informe Académico ? Thompson Gale, Estados Unidos / Latindex-Catálogo / Sociological Abstracts CSA-ProQuest, Estados Unidos / Ulrich´s Periodical Directory CSA-ProQuest, Estados Unidos. El artículo debate con el texto de Eduardo Basualdo publicado en esta revista en marzo de 2002, acerca de la crisis del régimen de Convertibilidad en Argentina. Discutimos la conceptualización de la unidad y el conflicto empresarial que este autor ubica en las privatizaciones de empresas estatales. Especialmente, ponemos en cuestión la conceptualización del conflicto empresarial como una polarización entre dos alternativas de salida de la convertibilidad: la devaluación de la moneda y la dolarización de la economía. Mostramos que la evidencia empírica a favor de esta tesis es escasa y que la unidad y el conflicto empresarial estuvieron relacionados más bien con la fortaleza o debilidad de una estrategia de acumulación.; The article debates Eduardo Basualdo’s text published in this magazine in March of 2002 regarding the crisis of the convertibility regime in Argentina. We discuss the conceptualization of business unity and conflict that this author locates in the privatizations of state companies. In particular, we question the conceptualization of business conflict as a polarization between two alternative solutions to convertibility –the devaluation of money and the dollarization of the economy. We show that the empirical evidence in favor of this thesis is scarce and that business unity and conflict were better yet related to the strength or the weakness of an accumulation strategy.

Pasiones prohibidas: lectoras, consumo y periodismo en la Argentina de 1880 Vicens, María Alrededor de 1875 comienzan a desarrollarse en la Argentina varios proyectos periodísticos que tienen a las lectoras como principales destinatarias. Publicaciones como La Ondina del Plata (1875-1880), La Alborada del Plata (1877- 1878 y 1880) y El Álbum del Hogar (1878-1880 y 1886-1887) conformaron un circuito de revistas en el que se entrecruzaban relatos literarios, ensayos de carácter moral y/o político, crónicas sociales y textos e imágenes sobre moda. Estos periódicos buscaron seducir y aleccionar a un sector emergente del público lector como el femenino, alternando discursos tradicionales con consignas y representaciones más vinculadas con un mercado de bienes de consumo en expansión. Este trabajo se propone analizar cómo estas revistas literarias para mujeres desarrollaron estrategias de negociación y censura frente al crecimiento del consumo femenino, aprovechando su atractivo comercial y arrogándose un lugar tutorial frente a los supuestos peligros y tentaciones que acechaban a las mujeres en la sociedad moderna.; Around 1875 several journalistic projects began to develop in Argentina which addressed specifically to women. Publications such as La Ondina del Plata (1875-1880), La Alborada del Plata (1877-1878 and 1880), and El Álbum del Hogar (1878- 1880 and 1886-1887) made up a circuit of magazines in which literature, moral and political essays, fashion texts and images, as well as reviews of social events intertwined. These periodicals sought to seduce and lecture an emerging sector of the reading public as women, alternating traditional discourses with slogans and representations related to an expanding consumer market. This paper analyzes how these literary women magazines developed different strategies of negotiation regarding the growth of women's consumption, using at the same time their commercial appeal and assuming a tutorial role against the alleged dangers and temptations that stalked women in modern society.

Patterns of daily and seasonal calling activity of a direct-developing frog of the subtropical Andean forests of Argentina Akmentins, Mauricio Sebastián; Pereyra, Laura Cecilia; Sanabria, Eduardo Alfredo; Vaira, Marcos Climate often regulates different aspects of the life cycle and activity of amphibians. Climatic seasonality may impose severe restrictions on breeding patterns of direct-developing terraranan frogs. We studied the influence of abiotic cues on calling activity of males of the direct-developing frog Oreobates discoidalis in the Yungas forests of north-western Argentina. Vocalization activity and daily emission pattern of the vocal repertoire were registered with a frog-logger, and climatic variables were registered with a data logger. We sampled two reproductive seasons from 2010 to 2011. We used ordinal logistic regression to evaluate the relationship between independent climatic variables and the intensity of calling activity. The calling season of males of O. discoidalis was triggered by the first rainfall of the aestival season. The species could be defined as crepuscular–nocturnal with a calling activity peak at dusk. Sporadic calling activity during day time was associated with conditions of high humidity and rainfall. Both the emission and the intensity of the advertisement call activity were influenced by time of the day, high levels of relative air humidity and presence of rainfall; air temperature was not a determinant factor in the calling activity of this frog species. Territorial calls were strongly associated with full chorus activity that could be associated with a mechanism of inter-male spacing.

Immunoreactivity of the 14F7 Mab raised against N-Glycolyl GM3 Ganglioside in retinoblastoma tumors Torbidoni, Ana Vanesa; Scursoni, Alejandra; Camarero, Sandra; Segatori, Valeria Inés; Gabri, Mariano Rolando; Alonso, Daniel Fernando; Chantada, Guillermo Luis; de Dávila, Maria Teresa Introduction The identification of molecules expressed selectively on the surface of retinoblastoma cells would allow applying targeted therapies. The Ganglioside, N-Glycolyl-GM3 (NeuGc-GM3), is an attractive candidate, as it has been detected in other paediatric neuroectodermic tumours, and it is not expressed in human normal tissues. The 14F7 antibody recognizes specifically the ganglioside NeuGc-GM3. Purpose To characterize the expression of NeuGc-GM3 in retinoblastoma cell lines and in retinoblastoma tumours using the 14F7 monoclonal antibody. Methods We studied WERI-Rb1 and Y79 cell lines, 24 retinoblastoma primary tumours from unilateral and bilateral cases and two bone marrow biopsies from metastatic retinoblastoma. Tumours were classified into three groups: non-invasive (n = 13), invasive (n = 9) and metastatic (n = 2). Three eyes enucleated because of non-tumoural conditions were used as controls. Cell lines and tumour sections were studied by immunohistochemistry using the 14F7 antibody. NeuGc-GM3 expression was evaluated by analysing the percentage of positive tumoural cells and the staining intensity. These parameters were analysed comparatively among the three groups. Results Both retinoblastoma cell lines showed immunoreactivity to NeuGc-GM3 but WERI-Rb1 presented higher intensity than Y79. All the tumours studied showed strong immunoreactivity to NeuGc-GM3 with no significant differences among groups. In both bone marrow specimens, NeuGc-GM3 immunoreactivity was observed in retinoblastoma cells. In bilaterally enucleated cases, NeuGc-GM3 immunoreactivity was not altered before and after chemotherapy. Non-tumoural retinas were negative. Conclusions NeuGc-GM3 is highly expressed in retinoblastoma cell lines, tumours and metastatic cells to the bone marrow, and it is not detectable in control eyes. There were no significant differences in the immunoreactivity to 14F7 among tumours from different disease stages. Its immunoreactivity did not change after chemotherapy.

Hierarchical Graphical Bayesian Models in Psychology; Modelos Bayesianos gráficos jerárquicos en psicología Campitelli, Guillermo Jorge; Macbeth, Guillermo Eduardo El mejoramiento de los métodos gráficos en la investigación en psicología puede promover su uso y una mejor compresión de su poder de expresión. La aplicación de modelos Bayesianos gráficos jerárquicos se ha vuelto más frecuente en la investigación en psicología. El objetivo de este trabajo es introducir sugerencias para el mejoramiento de los modelos Bayesianos gráficos jerárquicos en psicología. Este conjunto de sugerencias se apoya en la descripción y comparación entre los dos enfoques principales con el uso de notación y pictogramas de distribución. Se concluye que la combinación de los aspectos relevantes de ambos puede mejorar el uso de los modelos Bayesianos gráficos jerárquicos en psicología.; The improvement of graphical methods in psychological research can promote their use and a better comprehension of their expressive power. The application of hierarchical Bayesian graphical models has recently become more frequent in psychological research. The aim of this contribution is to introduce suggestions for the improvement of hierarchical Bayesian graphical models in psychology. This novel set of suggestions stems from the description and comparison between two main approaches concerned with the use of plate notation and distribution pictograms. It is concluded that the combination of relevant aspects of both models might improve the use of powerful hierarchical Bayesian graphical models in psychology.

Abiotic Degradation of Glyphosate into Aminomethylphosphonic Acid in the Presence of Metals Ascolani Yael, Julian Esteban; Fuhr, Javier Daniel; Bocan, Gisela Anahí; Daza Millone, Maria Antonieta; Tognalli, N.; Dos Santos Afonso, María; Martiarena, María Luz Glyphosate [N-phosphono-methylglycine (PMG)] is the most used herbicide worldwide, particularly since the development of transgenic glyphosate-resistant (GR) crops. Aminomethylphosphonic acid (AMPA) is the main glyphosate metabolite, and it may be responsible for GR crop damage upon PMG application. PMG degradation into AMPA has hitherto been reckoned mainly as a biological process, produced by soil microorganisms (bacteria and fungi) and plants. In this work, we use density functional calculations to identify the vibrational bands of PMG and AMPA in surface-enhanced Raman spectroscopy (SERS) and attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectra experiments. SERS shows the presence of AMPA after glyphosate is deposited from aqueous solution on different metallic surfaces. AMPA is also detected in ATR–FTIR experiments when PMG interacts with metallic ions in aqueous solution. These results reveal an abiotic degradation process of glyphosate into AMPA, where metals play a crucial role.

Death, personhood, and relatedness in the South Andes a thousand years ago Acuto, Felix Alejandro; Kergaravat, Marisa Soledad; Amuedo, Claudia Gabriela This article examines the nature of personhood in the Calchaquí region, in the South Andes,during the second part of the Late Intermediate Period (AD 1250?1450). Through the study of the location of graves, architecture, and offerings, the authors explore the type of personhood that Calchaquí communities built and represented through the materiality of funerary practice. They claim that in this cultural and historical context, death became a realm in which relatedness was interwoven. Death, symbolically and materially, built bridges, connecting and entangling people with place and with each other. The funerary sphere was not strategically used to celebrate particular biographies and personal accomplishments, but rather it was another realm, like daily life, where individual identity dissolved into place and into the collective.

Pensar el Estado a partir de la filosofía de Alain Badiou; Thinking about the State Based on the Philosophy of Alain Badiou Farrán, Roque En este artículo se presenta el concepto de estado que elabora Alain Badiou, en su dimensión ontológico-política, a fin de ensayar una modulación propia del concepto acorde con la especificidad de la problemática latinoamericana y la resignificación del Estado en los procesos políticos que tienen lugar en la región.; In this article, the concept of the state formulated by Alain Badiou is presented in its ontological-political dimension, in order to try a modulation belonging to the concept that agrees with the specificity of Latin American issues and the redefinition of the State in the political processes taking place in the region.

Ultrasound as a Method to Control Protein-Polysaccharide Foam Stability by Microscopic Parameter Alteration Martínez, Karina Dafne; Carrera-sánchez, Cecilio The objective of this work was to determine the effect of ultrasound application on the stability of foams of mixed systems of soy protein isolate and a hydroxypropyl methylcellulose called E4M at pH 7 and 3. It was used a soluble fraction of soy protein which is the responsible of functional properties in food applications. The pHs selected were used according to normally range in food meals. The samples were sonicated for 20 min using an ultrasonic processor Vibra Cell Sonics model VCX 750 at a frequency of 20 kHz and an amplitude of 20%. The foams were produced using a foaming instrument with a second CCD camera. The relative foam conductance (Cf%) and complementary parameters: half-life time, t½; relaxation times corresponding to the kinetics of liquid drainage, td; and disproportionation and collapse, tdc, were obtained. Significant differences were found for the relaxation times td and tdc at pH 7 as a consequence of the ultrasound treatment. It could be seen that ultrasound promoted a great increment of these relaxation times in these conditions, attributed to quantity of proteins at different pH.

Genome downsizing and karyotype constancy in diploid and polyploid congeners: a model of genome size variation Poggio, Lidia; Realini, Maria Florencia; Fourastié, María Florencia; Garcia, Ana Maria; González, Graciela Esther Evolutionary chromosome change involves significant variation in DNA amount in diploids and genome downsizing in polyploids. Genome size and karyotype parameters of Hippeastrum species with different ploidy level were analysed. In Hippeastrum, polyploid species show less DNA content per basic genome than diploid species. The rate of variation is lower at higher ploidy levels. All the species have a basic number x = 11 and bimodal karyotypes. The basic karyotypes consist of four short metacentric chromosomes and seven large chromosomes (submetacentric and subtelocentric). The bimodal karyotype is preserved maintaining the relative proportions of members of the haploid chromosome set, even in the presence of genome downsizing. The constancy of the karyotype is maintained because changes in DNA amount are proportional to the length of the whole-chromosome complement and vary independently in the long and short sets of chromosomes. This karyotype constancy in taxa of Hippeastrum with different genome size and ploidy level indicates that the distribution of extra DNA within the complement is not at random and suggests the presence of mechanisms selecting for constancy, or against changes, in karyotype morphology.

Application of hydrogen peroxide to the control of eutrophic lake systems in laboratory assays Bauzá, Letizia; Aguilera, Anabella; Etchenique, Roberto Argentino; Andrinolo, Dario; Giannuzzi, Leda We exposed water samples from a recreational lake dominated by the cyanobacterium Planktothrix agardhii to different concentrations of hydrogen peroxide (H2O2). An addition of 0.33 mg·L−1 of H2O2 was the lowest effective dose for the decay of chlorophyll-a concentration to half of the original in 14 h with light and 17 h in experiments without light. With 3.33 mg·L−1 of H2O2, the values of the chemical oxygen demand (COD) decreased to half at 36 and 126 h in experiments performed with and without light, respectively. With increasing H2O2, there is a decrease in the total and faecal coliform, and this effect was made more pronounced by light. Total and faecal coliform were inhibited completely 48 h after addition of 3.33 mg·L−1 H2O2. Although the densities of cyanobacterial cells exposed to H2O2 did not decrease, transmission electron microscope observation of the trichomes showed several stages of degeneration, and the cells were collapsed after 48 h of 3.33 mg·L−1 of H2O2 addition in the presence of light. Our results demonstrate that H2O2 could be potentially used in hypertrophic systems because it not only collapses cyanobacterial cells and coliform bacteria but may also reduce chlorophyll-a content and chemical oxygen demand.

Nanofiltration of glucose: Analysis of parameters and membrane characterization Almazán, Jorge Emilio; Romero Dondiz, Estela María; Rajal, Verónica Beatriz; Castro Vidaurre, Elza Fani Membrane characterization and modeling of nanofiltration processes of uncharged solutes are of special interest for the food industry. In this work two commercial membranes, DK and DL, were used to concentrate glucose solutions. Membranes were characterized according hydrophobicity, thickness, porosity, and hydraulic permeability. The influence of pressure and concentration of glucose on the permeate flux and rejection were studied. Both membranes presented a great potential for the food industry due to their high rejection of glucose. The osmotic pressure model was combined with film theory and the real driven force was calculated taking into account the osmotic pressure and the concentration polarization. Both phenomena influenced the process (concentration polarization only in the most dilute solutions at low pressure) and the permeability for glucose solutions was similar to the hydraulic permeability. A mathematical model based on the Donnan-Steric Pore Model was used to determine the pore radius and the effective thickness of both membranes. As the concentration inside the pore (needed for the calculations) is difficult to measure experimentally, various alternatives were proposed. The average of the concentration at the interface and permeate best fitted the experimental data. The model was applied successfully; the maximum error was 8% within the range of concentrations (5–100 g/L) for the DL membrane and 5% for the DK membrane up to 50 g/L.

Monopelopia caraguata (Chironomidae: Tanypodinae: Pentaneurini) and Phytotelmatocladius delarosai (Chironomidae: Orthocladiinae): Two Phytotelmatous Chironomids Distributed from Florida to Argentina Siri, Augusto; Donato, Mariano Humberto The geographic distribution of the 2 phytotelmatous chironomids Monopelopia caraguata and Phytotelmatocladius delarosai is expanded, and the occurrence of parthenogenesis in the last species is corroborated under laboratory conditions.; Se extiende la distribución geográfica de las especies fitotelmáticas Monopelopia caraguata y Phytotelmatocladius delarosai hacia el sur en Argentina, y se corrobora bajo condiciones de laboratorio la ocurrencia de partenogénesis en esta última especie.

Caveolinas y modulación del sistema del óxido nítrico en el hipotiroidismo según avanza la edad.; Age-related influence of hypothyroidism on caveolins and nitric oxide modulation Detomaso, Florencia M.; Braga, Paula; Rodríguez, Lourdes; Arreche, Noelia Daniela; Sarati, Lorena Ivonne; Balaszczuk, Ana María; Fellet, Andrea L. Introduction: Hypothyroidism and age impact on cardiac and renal nitricoxide (NO) production. Caveolins, which are negativemodulators of NO synthase (NOS) activity, are affected byboth factors. Objectives: The aim of this study was to evaluate caveolin (CAV) participationin the modulation of renal and cardiac NOS activityin adult hypothyroid animals. Methods: Euthyroid and hypothyroid [methimazole 0.02% (v/v) in thedrinking water during 28 days] male Sprague-Dawley ratswere used. Animals were sacrificed to remove the heart andkidneys. Results: Right atrial NOS activity decreased with age and hypothyroidism.Caveolin-1 expression increased with age andhypothyroidism. Conversely, left ventricular NOS activityincreased with aging and hypothyroidism and the expressionof both CAV isoforms decreased in adult and hypothyroidgroups. In the renal medulla, hypothyroidism reducedNOS activity in young and raised it in adult animals andCAV-1 expression decreased with age and in hypothyroidyoung animals. Caveolin-3 protein levels decreased in adulthypothyroid animals. Conclusions: Hypothyroidism impacts on NOS activity and on that ofits modulators, caveolins, in the cardiovascular and renalsystems. Hypothyroidism enhances the effects of aging inboth systems.

Divergent synthetic routes to biologically relevant types of compounds: chiral polyfunctional γ-lactams and amino acids Aguilera, Jordi; Moglioni, Albertina Gladys; Mor, Àlex; Ospina, Jimena; Illa, Ona; Ortuño, Rosa M. Divergent and versatile synthetic routes leading to the title compounds are described. They start from a common chiral precursor derived from (−)-(S)-verbenone and afford polyfunctional γ-lactams and γ- and ε-amino acids. The cyclobutane moiety in these molecules acts as a chiral and polyfunctional platform providing stereogenic centres with unambiguous absolute configuration that control the chirality of the newly produced asymmetric carbons. Furthermore, it affords functional groups and carbon chains suitable not only to create the basic skeleton of the desired products but additional functional groups. These features confer on these derivatives a great versatility for further uses in the development of new drugs and as synthetic building blocks.

Expression, localization and function of galectin-8, a tandem-repeat lectin, in human tumors Elola, Maria Teresa; Ferragut, Fátima; Cardenas Delgado, Victor Manuel; Nugnes, Lorena Gisela; Gentilini, Lucas Daniel; Laderach, Diego Jose; Troncoso, María Fernanda; Compagno, Daniel Georges; Wolfenstein, Carlota Elisa; Rabinovich, Gabriel Adrian Galectin-8 (Gal-8) is a ‘tandem-repeat’-type galectin, which possesses two carbohydrate recognition domains connected by a linker peptide. Gal-8 complexity is related to the alternative splicing of its mRNA precursor, which is known to generate isoforms. Regarding its carbohydrate-binding specificity, Gal-8 has a unique feature among galectins, since its C-terminal domain has higher affinity for N-glycan-type branched oligosaccharides, while its N-terminal domain shows strong affinity for α2-3-sialylated or 3’-sulfated ß-galactosides. We integrate here the available information on Gal-8 expression in different tumor types and attempt to elucidate associations of its expression and localization during tumor progression with the overarching goal of analyzing its potential applications in diagnosis and prognosis. Differential diagnosis is still a prime concern in tumor pathology, and Gal-8 could be of great value in some types of primary or secondary tumors (i.e. papillary thyroid carcinoma, advanced colon carcinoma from patients with distant metastases, or metastases from primary lung carcinoma). The prognostic value of Gal-8 has been described for laryngeal carcinoma as well as advanced colon carcinoma. Further studies are needed to explain the relevance of Gal-8 and its isoforms in tumor pathology and their different intra- or extracellular roles (cytoplasmic, nuclear or extracellular) in tumor biology.

Unveiling a crystalline topological insulator in a Weyl semimetal with time-reversal symmetry Arrachea, Liliana del Carmen; Aligia, Armando Angel We consider a natural generalization of the lattice model for a periodic array of two layers, A and B , of spinless electrons proposed by Fu [Phys. Rev. Lett. 106, 106802 (2011)] as a prototype for a crystalline insulator. This model has time-reversal symmetry and broken inversion symmetry. We show that when the intralayer next-nearest-neighbor hoppings t a 2 , a = A , B vanish, this model supports a Weyl semimetal phase for a wide range of the remaining model parameters. When the effect of t a 2 is considered, topological crystalline insulating phases take place within the Weyl semimetal one. By mapping to an effective Weyl Hamiltonian we derive some analytical results for the phase diagram as well as for the structure of the nodes in the spectrum of the Weyl semimetal.

The proinflammatory RAGE/NF-κB pathway is involved in neuronal damage and reactive gliosis in a model of sleep apnea by intermittent hypoxia Angelo, María Florencia; Aguirre, Alejandra Inés; Aviles Reyes, Rolando Xavier; Villarreal, Alejandro; Lukin, Jeronimo; Melendez, Matías; Vanasco, Virginia; Barker, Philip A.; Alvarez, Silvia; Epstein, Alberto Luis; Jerusalinsky, Diana Alicia; Ramos, Alberto Javier Sleep apnea (SA) causes long-lasting changes in neuronal circuitry, which persist even in patients successfully treated for the acute effects of the disease. Evidence obtained from the intermittent hypoxia (IH) experimental model of SA has shown neuronal death, impairment in learning and memory and reactive gliosis that may account for cognitive and structural alterations observed in human patients. However, little is known about the mechanism controlling these deleterious effects that may be useful as therapeutic targets in SA. The Receptor for Advanced Glycation End products (RAGE) and its downstream effector Nuclear Factor Kappa B (NF-κB) have been related to neuronal death and astroglial conversion to the pro-inflammatory neurodegenerative phenotype. RAGE expression and its ligand S100B were shown to be increased in experimental models of SA. We here used dissociated mixed hippocampal cell cultures and male Wistar rats exposed to IH cycles and observed that NF-κB is activated in glial cells and neurons after IH. To disclose the relative contribution of the S100B/RAGE/NF-κB pathway to neuronal damage and reactive gliosis after IH we performed sequential loss of function studies using RAGE or S100B neutralizing antibodies, a herpes simplex virus (HSV)-derived amplicon vector that induces the expression of RAGEΔcyto (dominant negative RAGE) and a chemical blocker of NF-κB. Our results show that NF-κB activation peaks 3 days after IH exposure, and that RAGE or NF-κB blockage during this critical period significantly improves neuronal survival and reduces reactive gliosis. Both in vitro and in vivo, S100B blockage altered reactive gliosis but did not have significant effects on neuronal survival. We conclude that both RAGE and downstream NF-κB signaling are centrally involved in the neuronal alterations found in SA models, and that blockage of these pathways is a tempting strategy for preventing neuronal degeneration and reactive gliosis in SA.

Synthesis and characterization of water-soluble dendronized chitosan using newkome-type dendrons Rimondino, Guido Noé; Strumia, Miriam Cristina; Martinelli, Marisa With increasing emphasis on environmental care 7 and use of renewable resources, simple and effective dendroniza- 8 tion processes were performed to obtain chitosan derivatives. We 9 present different alternatives for the modification of chitosan: 10 dendronization with a biocompatible dendron; a quaternization 11 process with an ammonium salt, which confers a permanent 12 positive charge to the polymer; and a combination of method- 13 ologies allowing amphiphilic polymers. This process confers 14 unique multivalent properties to the native chitosan, and further 15 modifications reach multivalent water-soluble polymers. Hence, 16 the most important highlight of this work is the use of renewable 17 natural polymers and the different methodologies applied to nontoxic solvents with low temperatures. The process described in 18 this paper represents a sustainable alternative for obtaining a functionalized material with properties suitable for application in 19 different areas, such as biomedicine or environmental remediation.

Iodine Staining of Escherichia coli Expressing Genes Involved in the Synthesis of Bacterial Glycogen Demonte, Ana M.; Asención Diez, Matías Damián; Guerrero, Sergio Adrian; Ballicora, Miguel A.; Iglesias, Alberto Alvaro The presence of intracellular glycogen can be detected by the following iodine staining technique. Cells with glycogen stain dark brown, whereas in its absence they remain with a pale yellowish color. It is hypothesized that iodine atoms fit into helical coils formed by the α-polyglucan to form a coloured glycogen-iodine complex. Here, we have studied the expression of Streptococcus mutans (S. mutans) genes that control the biosynthesis of this polysaccharide. Thus, we expressed glgC and glgD genes coding for both ADP-Glc pyrophosphorylase subunits in Escherichia coli (E. coli) AC70R1-504 cells to complement the deficient accumulation of glycogen by this strain. In control cells or in those where an inactive protein was expressed, the synthesis of the polysaccharide was undetectable by this iodine staining technique.