Hipoplasia dérmica focal (síndrome de Goltz) / Focal dermal hypoplasia (Goltz syndrome)

Resumen: Introducción: La hipoplasia dérmica focal o síndrome de Goltz es una rara genodermatosis de herencia dominante ligada al X, que afecta al tejido proveniente de las placas del ectodermo y del mesodermo. El cuadro clínico se caracteriza por alteraciones cutáneas, oftálmicas, neurológicas, dentales, ungueales, bucales, de tejidos blandos y esqueléticas. El diagnóstico se realiza por los hallazgos clínicos en un individuo con alteraciones ectodérmicas y malformaciones características en las extremidades. El manejo es multidisciplinario y, al igual que el pronóstico, depende de las alteraciones específicas que presente cada paciente. Caso clínico: Se presenta el caso de un recién nacido de sexo femenino, de 15 días de vida, con zonas de alopecia en piel cabelluda, herniación de tejido celular subcutáneo en varias áreas de todos los segmentos corporales, escotadura en ala nasal, hendidura en encía superior, defecto grave de extremidad superior izquierda con rizomelia (acortamiento de segmento proximal) y aplasia de radio, así como ectrodactilia de miembro pélvico derecho. Todos los hallazgos son compatibles con hipoplasia dérmica focal de acuerdo con los criterios diagnósticos. Conclusiones: Se presenta el caso de una paciente recién nacida con síndrome de Goltz.

Abstract: Background: Focal dermal hypoplasia or Goltz syndrome is a rare X-linked dominant inherited genodermatosis, affecting both the ectodermal and mesodermal tissue. Clinical manifestations include skin abnormalities, defects in eyes, teeth, nails, mouth, soft tissues and skeleton. The diagnosis is based on clinical findings and is suspected in individuals with ectodermal abnormalities and characteristic malformations in the extremities. The management is multidisciplinary and, like the prognosis, depends on the specific alterations that each patient presents. Case report: We report the case of a 15-day-old female newborn with alopecic areas on the scalp, herniation of subcutaneous cellular tissue at the lumbar level, nasal wing notch, severe left superior limb defect with rhizomelia (proximal segment shortening) and radio aplasia, as well as right leg ectrodactyly, areas of atrophy compatible with focal dermal hypoplasia according to diagnostic criteria. Conclusions: We present a case of female newborn patient with Goltz syndrome.

[Focal dermal hypoplasia (Goltz syndrome)]. / Hipoplasia dérmica focal (síndrome de Goltz).

Background: Focal dermal hypoplasia or Goltz syndrome is a rare X-linked dominant inherited genodermatosis, affecting both the ectodermal and mesodermal tissue. Clinical manifestations include skin abnormalities, defects in eyes, teeth, nails, mouth, soft tissues and skeleton. The diagnosis is based on clinical findings and is suspected in individuals with ectodermal abnormalities and characteristic malformations in the extremities. The management is multidisciplinary and, like the prognosis, depends on the specific alterations that each patient presents. Case report: We report the case of a 15-day-old female newborn with alopecic areas on the scalp, herniation of subcutaneous cellular tissue at the lumbar level, nasal wing notch, severe left superior limb defect with rhizomelia (proximal segment shortening) and radio aplasia, as well as right leg ectrodactyly, areas of atrophy compatible with focal dermal hypoplasia according to diagnostic criteria. Conclusions: We present a case of female newborn patient with Goltz syndrome.

Introducción: La hipoplasia dérmica focal o síndrome de Goltz es una rara genodermatosis de herencia dominante ligada al X, que afecta al tejido proveniente de las placas del ectodermo y del mesodermo. El cuadro clínico se caracteriza por alteraciones cutáneas, oftálmicas, neurológicas, dentales, ungueales, bucales, de tejidos blandos y esqueléticas. El diagnóstico se realiza por los hallazgos clínicos en un individuo con alteraciones ectodérmicas y malformaciones características en las extremidades. El manejo es multidisciplinario y, al igual que el pronóstico, depende de las alteraciones específicas que presente cada paciente. Caso clínico: Se presenta el caso de un recién nacido de sexo femenino, de 15 días de vida, con zonas de alopecia en piel cabelluda, herniación de tejido celular subcutáneo en varias áreas de todos los segmentos corporales, escotadura en ala nasal, hendidura en encía superior, defecto grave de extremidad superior izquierda con rizomelia (acortamiento de segmento proximal) y aplasia de radio, así como ectrodactilia de miembro pélvico derecho. Todos los hallazgos son compatibles con hipoplasia dérmica focal de acuerdo con los criterios diagnósticos. Conclusiones: Se presenta el caso de una paciente recién nacida con síndrome de Goltz.

The mitochondrial alternative oxidase Aox1 is needed to cope with respiratory stress but dispensable for pathogenic development in Ustilago maydis.

The mitochondrial alternative oxidase is an important enzyme that allows respiratory activity and the functioning of the Krebs cycle upon disturbance of the respiration chain. It works as a security valve in transferring excessive electrons to oxygen, thereby preventing potential damage by the generation of harmful radicals. A clear biological function, besides the stress response, has so far convincingly only been shown for plants that use the alternative oxidase to generate heat to distribute volatiles. In fungi it was described that the alternative oxidase is needed for pathogenicity. Here, we investigate expression and function of the alternative oxidase at different stages of the life cycle of the corn pathogen Ustilago maydis (Aox1). Interestingly, expression of Aox1 is specifically induced during the stationary phase suggesting a role at high cell density when nutrients become limiting. Studying deletion strains as well as overexpressing strains revealed that Aox1 is dispensable for normal growth, for cell morphology, for response to temperature stress as well as for filamentous growth and plant pathogenicity. However, during conditions eliciting respiratory stress yeast-like growth as well as hyphal growth is strongly affected. We conclude that Aox1 is dispensable for the normal biology of the fungus but specifically needed to cope with respiratory stress.

Artificial biomembrane based on DPPC--Investigation into phase transition and thermal behavior through ellipsometric techniques.

Organic thin film deposition presents a multiplicity of challenges. Most notably, layer thickness control, homogeneity and subsequent characterization have been not cleared yet. Phospholipid bilayers are frequently used to model cell membranes. Bilayers can be disrupted by changes in mechanical stress, pH and temperature. The strategy presented in this article is based on thermal study of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) through analysis of slight changes in material thickness. The sample was prepared by depositing X- or Y-type DPPC bilayers using Langmuir-Blodgett technique over silicon wafer. Thus, molecular inclination degree, mobility and stability of phases and their respective phase transitions were observed and analyzed through ellipsometric techniques during heating cycles and corroborated by Grazing Incidence X-ray Diffraction and Atomic Force Microcopy measurements. DPPC functional group vibrations were detected by Raman spectra analysis. Scanning Electron Microscope with Field Emission gun (FE-SEM) and conventional SEM micrographs were also used to characterize sample morphology, demonstrating that homogenous bilayer formations coexist with some vesicles or micelles at surface level. Contact angle measurements corroborate DPPC surface wettability, which is mainly related to surface treatment methods of silicon wafer used to create either hydrophilic or hydrophobic nature regarding the substrate surface. Also, shifting and intensity changes of certain functional groups into Raman spectra confirm water presence between DPPC layers. Signal analysis detects certain interdigitation between aliphatic chains. These studies correspond to the base of future biosensors based on proteins or antimicrobial peptides stabilized into phospholipid bilayers over thin hydrogel films as moist scaffold.

Role of transmembrane segment M8 in the biogenesis and function of yeast plasma-membrane H(+)-ATPase.

Of the four transmembrane helices (M4, M5, M6, and M8) that pack together to form the ion-binding sites of P(2)-type ATPases, M8 has until now received the least attention. The present study has used alanine-scanning mutagenesis to map structure-function relationships throughout M8 of the yeast plasma-membrane H(+)-ATPase. Mutant forms of the ATPase were expressed in secretory vesicles and at the plasma membrane for measurements of ATP hydrolysis and ATP-dependent H(+) pumping. In secretory vesicles, Ala substitutions at a cluster of four positions near the extracytoplasmic end of M8 led to partial uncoupling of H(+) transport from ATP hydrolysis, while substitution of Ser-800 (close to the middle of M8) by Ala increased the apparent stoichiometry of H(+) transport. A similar increase has previously been reported following the substitution of Glu-803 by Gln (Petrov, V. et al., J. Biol. Chem. 275:15709-15718, 2000) at a position known to contribute directly to Ca(2+) binding in the Ca(2+)-ATPase of sarcoplasmic reticulum (Toyoshima, C., et al., Nature 405: 647-655, 2000). Four other mutations in M8 interfered with H(+)-ATPase folding and trafficking to the plasma membrane; based on homology modeling, they occupy positions that appear important for the proper bundling of M8 with M5, M6, M7, and M10. Taken together, these results point to a key role for M8 in the biogenesis, stability, and physiological functioning of the H(+)-ATPase.

The physiologic role of alternative oxidase in Ustilago maydis.

Alternative oxidase (AOX) is a ubiquitous respiratory enzyme found in plants, fungi, protists and some bacterial species. One of the major questions about this enzyme is related to its metabolic role(s) in cellular physiology, due to its capacity to bypass the proton-pumping cytochrome pathway, and as a consequence it has great energy-wasting potential. In this study, the physiological role and regulatory mechanisms of AOX in the fungal phytopathogen Ustilago maydis were studied. We found evidence for at least two metabolic functions for AOX in this organism, as a major part of the oxidative stress-handling machinery, a well-described issue, and as part of the mechanisms that increase the metabolic plasticity of the cell, a role that might be valuable for organisms exposed to variations in temperature, nutrient source and availability, and biotic or abiotic factors that limit the activity of the cytochrome pathway. Experiments under different culture conditions of ecological significance for this organism revealed that AOX activity is modified by the growth stage of the culture, amino acid availability and growth temperature. In addition, nucleotide content, stimulation of AOX by AMP and respiratory rates obtained after inhibition of the cytochrome pathway showed that fungal/protist AOX is activated under low-energy conditions, in contrast to plant AOX, which is activated under high-energy conditions. An estimation of the contribution of AOX to cell respiration was performed by comparing the steady-state concentration of adenine nucleotides, the mitochondrial membrane potential, and the respiratory rate.

The mitochondrial respiratory chain of Ustilago maydis.

Ustilago maydis mitochondria contain the four classical components of the electron transport chain (complexes I, II, III, and IV), a glycerol phosphate dehydrogenase, and two alternative elements: an external rotenone-insensitive flavone-sensitive NADH dehydrogenase (NDH-2) and an alternative oxidase (AOX). The external NDH-2 contributes as much as complex I to the NADH-dependent respiratory activity, and is not modulated by Ca2+, a regulatory mechanism described for plant NDH-2, and presumed to be a unique characteristic of the external isozyme. The AOX accounts for the 20% residual respiratory activity after inhibition of complex IV by cyanide. This residual activity depends on growth conditions, since cells grown in the presence of cyanide or antimycin A increase its proportion to about 75% of the uninhibited rate. The effect of AMP, pyruvate and DTT on AOX was studied. The activity of AOX in U. maydis cells was sensitive to AMP but not to pyruvate, which agrees with the regulatory characteristics of a fungal AOX. Interestingly, the presence of DTT during cell permeabilisation protected the enzyme against inactivation. The pathways of quinone reduction and quinol oxidation lack an additive behavior. This is consistent with the competition of the respiratory components of each pathway for the quinol/quinone pool.

Estreptomicina: propiedades fisicoquímicas y toxicidad vestibular / Streptomycin, physical and chemical characteristics and vestibular toxicity

Propósito: Los antibióticos aminoglucósidos estreptomicina (STP) y kanamicina (KAN) son tóxicos para las células sensoriales del vestíbulo y de la cóclea, respectivamente. Químicamente están constituidos por estreptidina (STD) un derivado del inositol y dos azúcares, la esteptosa (Stosa) y la N-metilglucosamida (nm-GLUN); sin embargo, en la STP, la STD tiene dos sustituyentes guanidino, los que están ausentes en la KAN. Por lo tanto, se propone estudiar si la vestíbulo-toxicidad específica de la STP se debe a los grupos guanidino. Material y Métodos: Se incubaron en vitro, membranas celulares aisladas de los órganos vestibulares, con 3H-espermidina (3H-Spdina), un análogo estructural de la STP. Se midió la capacidad de los siguientes compuestos: STP, STD, KAN, guanidina (GUA) y n-acetilglucosamina (na-GLUN) para desplazarlos específicamente. Resultados: Se encontró que el orden de desplazamiento de la 3HSPdina para esas sustancia era STP=STD KanGUAn-a-GLUN. Conclusiones: Los resultados sugieren fuertemente que la STP debe su especificidad vestibulotóxica, a la presencia de los grupos guanidino en la porción de STD de su molécula, los que interactuarían por sus cargas positivas con estructuras membranales vestibulares relacionadas con la transducción, muy probablemente los cilios sensorios de las células ciliadas vestibulares