Oxidative stress and antioxidant response in a thermotolerant yeast

Abstract Stress tolerance is a key attribute that must be considered when using yeast cells for industrial applications. High temperature is one factor that can cause stress in yeast. High environmental temperature in particular may exert a natural selection pressure to evolve yeasts into thermotolerant strains. In the present study, three yeasts (Saccharomyces cerevisiae, MC4, and Kluyveromyces marxianus, OFF1 and SLP1) isolated from hot environments were exposed to increased temperatures and were then compared with a laboratory yeast strain. Their resistance to high temperature, oxidative stress, and antioxidant response were evaluated, along with the fatty acid composition of their cell membranes. The SLP1 strain showed a higher specific growth rate, biomass yield, and biomass volumetric productivity while also showing lower duplication time, reactive oxygen species (ROS) production, and lipid peroxidation. In addition, the SLP1 strain demonstrated more catalase activity after temperature was increased, and this strain also showed membranes enriched in saturated fatty acids. It is concluded that the SLP1 yeast strain is a thermotolerant yeast with less oxidative stress and a greater antioxidant response. Therefore, this strain could be used for fermentation at high temperatures.

Curcumin restores mitochondrial functions and decreases lipid peroxidation in liver and kidneys of diabetic db/db mice

BACKGROUND: Nitrosative and oxidative stress play a key role in obesity and diabetes-related mitochondrial dysfunction. The objective was to investigate the effect of curcumin treatment on state 3 and 4 oxygen consumption, nitric oxide (NO) synthesis, ATPase activity and lipid oxidation in mitochondria isolated from liver and kidneys of diabetic db/db mice. RESULTS: Hyperglycaemia increased oxygen consumption and decreased NO synthesis in liver mitochondria isolated from diabetic mice relative to the control mice. In kidney mitochondria, hyperglycaemia increased state 3 oxygen consumption and thiobarbituric acid-reactive substances (TBARS) levels in diabetic mice relative to control mice. Interestingly, treating db/db mice with curcumin improved or restored these parameters to normal levels; also curcumin increased liver mitochondrial ATPase activity in db/db mice relative to untreated db/db mice. CONCLUSIONS: These findings suggest that hyperglycaemia modifies oxygen consumption rate, NO synthesis and increases TBARS levels in mitochondria from the liver and kidneys of diabetic mice, whereas curcumin may have a protective role against these alterations.

Genomic organization of nucleolin gene in carp fish: Evidence for several genes

The protein nucleolin, functionally involved in the main steps of ribosome biogenesis, is codified by a single copy gene in mammals. Here we report that at least three different genes codify for this protein in carp fish (Cyprinus carpio). This is the first description of the genomic organization of nucleolin in a teleost. The carp nucleolin gene includes 8.8 kb and contains 16 exons. Promoter cis regulatory elements are similar to constitutive genes, i.e., a putative TATA box, three G/C boxes, and three pyrimidine-rich boxes. As in other species, carp nucleolin gene introns host three snoRNA codifying sequences: U23 from the H/ACA family and two C/D box snoRNAs, U20 and U82. Both U20 and U82 span a complementary sequence with carp 18S rRNA. Additionally, we identified two cDNAs coding for nucleolin, confirming the existence of several nucleolin genes in carp. Amino acid-derived sequence from carp cDNAs differ from mammal protein because they span additional acidic domains at the amino end, whose functional significance remains unclear. We performed amino acid sequence comparison and phylogenetic analyses showing that the three isoforms of carp nucleolin, which we describe herein, cluster in two groups. cNUC1 probably diverges from cNUC2 and cNUC3 as result of ancestral fish-specific genome duplication, indeed C. carpio is a tetraploid fish.

Evolución de la frecuencia de factores de riesgo cardiovascular en dos poblaciones chilenas / Changes in cardiovacular risk factors in two chilean populations

Objetivos: Establecer cambios en la frecuencia de factores de riesgo cardiovascular entre 1993 y 2001 en dos poblaciones étnicas chilenas. Materiales: En los años 1993 y 2001, se estudiaron 960 individuos adultos (625 mujeres y 335 hombres) de la comuna de la Florida (Santiago) y 113 habitantes (63 mujeres y 50 hombres) de la Isla Huapi (X región). Se estableció la frecuencia de: diabetes mellitus (DM): dos glicemias en ayuno ≥126 mg/dl o antecedente clínico de diabetes, obesidad: IMC ≥30 kg/mt², hipertensión arterial (HTA): PAS ≥140 y/o PAD ≥90 o tratamiento antihipertensivo, hipercolesterolemia: colesterol total ≥200 mg/dl y tabaquismo: consumo de al menos un cigarrillo en el último mes. Resultados: En el año 2001 en comparación a 1993, se detectó en la población de La Florida, un incremento significativo de la frecuencia de obesidad (13 por ciento), de DM (63 por ciento), de hipercolesterolemia (24 por ciento) y un leve pero significativo aumento de la HTA (3 por ciento). El tabaquismo disminuyó significativamente en un 8 por ciento. En la Isla Huapi se observó un incremento significativo de la frecuencia de obesidad (22 por ciento), de DM (105 por ciento) y de hipercolesterolemia (9 por ciento). No se detectaron cambios en la frecuencia de HTA. El tabaquismo disminuyó significativamente en alrededor de un 50 por ciento. Conclusiones: En los últimos años, la población chilena presenta un aumento progresivo de la frecuencia de obesidad, DM y dislipidemia, lo cual favorecería el aumento de la morbimortalidad cardiovascular.

Genomic organization of the rDNA cistron of the teleost fish Cyprinus carpio

The seasonal adaptation of the teleost Cyprinus carpio to the cyclical changes of its habitat demands physiological compensatory responses. The process involves profound nucleolar adjustments and remarkable changes in rRNA synthesis, which affects ribosomal biosynthesis. In this context, we have demonstrated that the synthesis of several proteins involved in ribosomal biogenesis as protein kinase CK2, ribosomal protein L41 and nucleolin, as well as U3 snoRNP, are differentially regulated in summer-acclimatized carp compared to the cold-season adapted fish. To understand the mechanisms involved in the seasonal regulation of rRNA gene transcription, we have been studying the carp rDNA cistron structure. Because the cis-elements that regulate the expression of the tandem organized ribosomal genes are located in the non-transcribed intergenic spacer (IGS), we analyzed the primary structure of the carp rDNA gene IGS. The gene organization is similar to that described from other vertebrate species, including numerous repetitive sequences, the transcription start site, and some potential cis-elements such as ribosomal enhancers, proximal terminator and transcriptional terminators. Ribosomal DNA is a remarkable case of gene duplication and has been used as a model to test the concerted evolution theory. We performed sequence comparison analyses of 18S rRNA coding sequences from carp with different species, data with which an unrooted phylogram was constructed

Correción tridimensional de deformidades escolióticas torácicas con la tracción transversa a dos años de evolución / Tridimensional correction of thoracic scoliotic deformities by transoperative transverse

Se presentan 10 pacientes con escoliosis torácica idiopática a quienes se les realizó corrección quirúrgica en el plano tridimensional, que se consideró necesaria en virtud de que en el segmento torácico con frecuencia disminuye la cifosis torácica y por lo tanto disminuye la capacidad de dicha cavidad. La corrección se hizo mediante tracción en el plano transversal, por medio de alambrado de la costilla apical en el lado cóncavo y del mecanismo del marco de Cotrel que se usó como auxiliar en quirófano, a un lado del campo quirúrgico. Una vez corregida la curva se aplicó instrumentación segmentaria de Luque. Se obtuvo un 52 por ciento de corrección de la curva en el plano frontal y una ganancia de 9.7 grados de cifosis torácica funcional.

Effect of hypoxia and reoxygenation on metabolic pathways in rat hepatocytes

Background. The mechanisms whereby rat hepatocytes undergo irreversible injury due to a lack of oxygen have not been established. Methods. Liver cells were used for reperfusion injury, and four compartmentalized pathways were evaluated durgin hypoxia (N2/CO2, 19:1) for 30 min followed by oxygen (O2/CO2, 19:1) for 30 min. Results. Cell viability decreased during the hypoxic, but not during the reoxygenation, phase. Glycogenolysis, as measured by glucose release, was significantly increased during hypoxia as compared to control in oxygen (205ñ15 vs. 155 ñ 10 mmol glucose/mg protein/h, respectiely), and did not return to normal levels by reoxygenation. Gluconeogenesis was importantly decreased during hypoxia (102 ñ 10 vs. 8 ñ 2 mmol glucose/mg protein/h) with partial recovery during reoxygenation. Ureagenesis diminished in hypoxia, but recovered during reoxygenation. Additionally, 3-hydroxy-butyrate formation was augmented by hypoxia, with some recovery when oxygen was present. Conclusions. These results suggest that compartmentalized pathways are protected from hypoxic injury in isolated hepatocytes, and also suggest it as a model to test the idea that enzymes of those parthways are organized into multienzyme complexes in vivo

Valor del abordaje quirúrgico anterior en el tratamiento de la escoliosis estructurada / The importance of the anterior surgical approach in the treatment of structural scoliosis

Se realizó un análisis clínico y radiográfico de 269 pacientes tratados quirúrgicamente por vía anterior, para la corrección de deformidades estructurales de la columna, durante un periodo de ocho años. Los resultados fueron satisfactorios al lograrse correcciones de hasta un 60 por ciento con mínimas complicaciones imputables al procedimiento considerando que en este se incluyeron disquectomías, osteotomías y vertebrectomías. Se demuestra así la utilidad del abordaje anterior en el tratamiento de las deformidades rígidas de la columna, independientemente de su etiología ya sea como procedimiento único o aunado a otro procedimiento por vía posterior

Inestabilidad post-quirúrgica de la columna vertebral que produce daño neurológico / Post-operative instability of the spine that produces neurological damage

El tratamiento óptimo de las lesiones secundarias a cirugía correctiva de escoliosis, es controversial, por lo que se requiere con base en conocimientos actuales llevar a cabo en forma adecuada el tratamiento de estas complicaciones. Se estudian cuatro pacientes que cursaron con deterioro neurológico consecutivo a una intervención quirúrgica y que requirieron reintervención con el fin de revertir el daño neurológico. Se analizan los casos en relación con el tiempo y método usado en cada uno de ellos determinando la importancia de la estabilización anterior y de la columna intermedia de Denis en los resultados

Severa cifosis lumbar post-quirúrgica, en presencia de síndrome de Marfan: informe de un caso / Post-operative severe lumbar kyphosis in a patient who has Marfa's Syndrome

Se presenta el caso de una paciente de 14 años de edad con síndrome de Marfan que desarrolló severa cifosis postquirúrgica en la región lumbar; que se constituyó en una grotesca deformidad del tronco. La paciente se presentó habiendo sido operada con tres pares de barras de Harrington que no corrigieron la deformidad. El tratamiento definitivo consistió en osteotomías y alambrado de la funsión posterior, función anterior con un injerto autógeno de peroné de T-10 a L-4. El tratamiento finalmente fue resolutivo de la severa deformidad. Solamente se encontró un caso similar reportado en la literatura

Escoliosis idiopática: experiencia de 100 casos quirúrgicos / Idiopatic scoliosis: a series of 100 surgical cases

En este estudio se analizan 100 pacientes con escoliosis idiopática que fueron tratados quirúrgicamente, mediante artroidesis y corrección con instrumentación distractora de Harrington con alambrado sublaminar total (incluyendo los ganchos) en 87 casos barra lisa de Luque en 13 casos (incluyendo tres casos de vertebrectomía). La corrección inicial fue de 55 por ciento y la corrección final a 21 meses de 41 por ciento. La pseudoartrosis fue la principal complicación con siete casos. Se discuten las indicaciones de cada instrumentación.