STABILITY AND FOLDING OF MUTANT FORMS OF ISO-1 CYTOCHROME-C FROM SACCHAROMYCES CEREVISIAE

Partially functional forms of iso-1-cytochrome c from Saccharomyces cerevisiae were obtained by replacements of the evolutionarily conserved proline 71 with valine, isoleucine and threonine (Ernst et.al.,1985). Pro-71 lies at the juncture of two short helical regions and is believed to be important for proper local polypeptide chain folding within the iso-1-cytochrome c structure.^ To study folding in the absence of intermolecular disulfide dimer formation the free sulfhydryl group of Cys-102 was modified in both wild type and mutant proteins with an alkylating reagent, methyl methanethiosulfonate. Spectral analysis of the wild type and mutant proteins shows that the native-like functional (or partially functional) folded structure of cytochrome c is retained in the chemically modified derivatives. The replacement of Pro-71 with valine, isoleucine or threonine reduces the intensity of the 696 nm absorbance band which is an indicator of the Met-80 ligation to the heme. Thermal stability and guanidine hydrochloride unfolding studies of the mutant proteins shows a destabilization of the protein as a result of mutation. The degree of destabilization depends on the chemical nature of the substituent amino acid in the mutant protiens.^ Kinetics of folding/unfolding reactions of the proteins were monitored by fluorescence changes using stopped flow mixing to obtain guanidine hydrochloride concentration jumps ending below, within, and above the transition zone. The replacement of Pro-71 alters the rate on one of the fastest phases, $\tau\sb3$, while the two other phases, $\tau\sb1$ & $\tau\sb2$, remain the same.^ Slow refolding kinetic studies indicate that replacement of Pro-71 does not completely eliminate the absorbance or fluorescence detected slow phases leading to the conclusion that Pro-71 is not involved in the generation of the slow phases in the folding kinetics of iso-1-cytochrome c.^ The alkaline conformational change involving the disappearance of the 696 nm absorbance band occurs with increasing pH in the alkaline pH region (Davis et al., 1974). The apparent pK of this conformational change in mutant proteins is shifted as much as two pH units compared to wild type. The equilibrium and kinetic data of alkaline transition for the wild type follows a simple mechanism proposed by Davis et al., (1974) for horse heart cytochrome c. A more complex mechanism is proposed for the behavior of the mutant proteins. ^

Structure/affinity studies in the bicyclo-DNA series: Synthesis and properties of oligonucleotides containing bcen-T and iso-tricyclo-T nucleosides

We present the synthesis of the two novel nucleosides iso-tc-T and bcen-T, belonging to the bicyclo-/tricyclo-DNA molecular platform. In both modifications the torsion around C6’–C7’ within the carbocyclic ring is planarized by either the presence of a C6’–C7’ double bond or a cyclopropane ring. Structural analysis of these two nucleosides by X-ray analysis reveals a clear preference of torsion angle γ for the gauche orientation with the furanose ring in a near perfect 2’-endo conformation. Both modifications were incorporated into oligodeoxynucleotides and their thermal melting behavior with DNA and RNA as complements was assessed. We found that the iso-tc-T modification was significantly more destabilizing in duplex formation compared to the bcen-T modification. In addition, duplexes with complementary RNA were less stable as compared to duplexes with DNA as complement. A structure/affinity analysis, including the already known bc-T and tc-T modifications, does not lead to a clear correlation of the orientation of torsion angle γ with DNA or RNA affinity. There is, however, some correlation between furanose conformation (N- or S-type) and affinity in the sense that a preference for a 3’-endo like conformation is associated with a preference for RNA as complement. As a general rule it appears that Tm data of single modifications with nucleosides of the bicyclo-/tricyclo-DNA platform within deoxyoligonucleotides are not predictive for the stability of fully modified oligonucleotides.

Síndrome de Iso Kikuchi. Reporte de dos casos

We report 2 cases of Iso Kikuchi syndrome: A new born female patient with a 21 days history and a 62 year-old male. We present two cases of this unusual congenital abnormality of the nails at the extremes of life.

Blütenknospen : Aristolochia elegans - Stanhopea graveolens - Aristolochia tricandata - Bulbophyllum lobbii - Aristolochia tricandata - Nicotiana affinis

AR

Tabak : Nicotiana sylvestris - Nicotiana sanderi - Nicotiana affinis

AR

Certificación de normas ISO

Es común percibir que, en la empresas pequeñas o que recién comienzan, el mecanismo de control asociado es el de observación directa por parte del propietario. En cambio para las empresas de mayor tamaño, existen mecanismos más sofisticados de control que permiten realizar un registro más profundo de las actividades, su desarrollo y por sobre todo su adecuación con los objetivos de la firma. Más allá de ser una pequeña o gran empresa, cada una debería implementar un Sistema de Control de Gestión para facilitar el mejoramiento continuo de cada elemento de la organización. Lecar S.A. es una empresa familiar dedicada a la compra - venta de automotores nuevos y usados en la provincia de Mendoza, que ha sufrido a lo largo de sus años varias modificaciones en su estructura, pero nunca logró establecer un orden formal en sus actividades. Se podría decir, que un problema desde el punto de vista social, es una dificultad o impedimento que se interpone para el desarrollo normal de una situación, y por lo tanto requiere de una solución. Los objetivos de este trabajo se pueden disgregar en uno general que es el de formular y documentar un manual de políticas y procedimientos para las áreas operativas más importantes de Lecar S.A. y otros, un tanto más específicos, como analizar la empresa Lecar S.A. en su estado actual, analizar los beneficios y costos de los manuales de políticas y procedimientos en una empresa familiar, establecer conocimientos generales sobre calidad en la gestión y realizar un acercamiento a los instrumentos de certificación de normas de calidad en la gestión de las empresas.

Pollen profiles from 8 sediment cores from the Degersee, Southern Germany

The discovery of a neolithic pile field in the shallow water near the eastern shore of the Degersee confirmed earlier palynological and sedimentological studies stating that early man was active in the region since more than 6000 years. The already available off-site data were freshly assessed, completed by additional data from old and new cores and the interpretations revised. A common time scale for the off-site data and the on-site data was obtained by AMS dating of terrestrial macro remains of the neolithic section of off-site core De_I+De_H. The ages can thus be parallelled with AMS ages of construction timber on-site. Pollen analyses from all cores provide a further time scale. The continuously and densely sampled pollen profile of the profundal zone embracing the entire Late glacial and Holocene serves as a reference. From the Boreal onwards the relative ages are transformed by AMS ages and varve counts into calibrated and absolute. A transect cored close to the neolithic pile field across the lake marl-platform demonstrates its geological architecture in the shallow water since the Lateglacial. Studies of the microfabric of thin sections of drilled cores and of box cores from the excavations demonstrate that neolithic settlements now at 2-3,5 m water depth had been erected on lake marl freshly fallen dry, thus indicating earlier lake levels dropped by 1.5-2 m. The neolithic section of the highly resolved off-site profile in the lake=s profundal zone has laminated and calcareous zones alternating with massive ones. Assemblages of diatoms and concentrations of trace elements changing simultaneously characterise the calcareous sections as deposits of low lake levels that lasted between some 40 and more than 300 years. The ages of discovered lake shore dwellings fall into calcareous segments with low lake levels. From the end of the Upper Atlantic period (F VII) appear Secondary Forest Cycles in the beech forest, a man-made sequence of repeated vegetational development with an identical pattern: With a decrease of beech pollen appear pollen of grasses, herbs and cultural indicators. These are suppressed by the light demanding hazel and birch, those again by ash, and finally by the shade demanding beech forming a new pollen peak. Seven main Forest Cycles are identified In the upper Neolithic period each comprising some 250, 450 or 800 years. They are subdivided into subcycles that can be broken down by very dense sampling in even shorter cycles of decadal length. Farming settlers have caused minor patchy clearances of the beech-mixed-forest with the use of fire. The phases of clearance coincide with peaks of charcoal and low stands of the lake levels. The Secondary Forest Cycles and the continuous occurrence of charcoal prove a continued occupation of the region. Together with the repeated restoration of the beech climax forest they point to pulsating occupation probably associated with dynamic demography. The synchronism of the many palynological, sedimentological and archaeological data point to an external forcing as the climate that affects comprehensively all these proxies. The fluctuations of the activity of the sun as manifested in the residual d14C go largely along with the proxies. The initial clearances at the begin of the forest cycles are linked to low lake levels and negative values of d14C that point to dry and warm phases of a more continental climate type. The subcycles exist independent from climatic changes, indicating that early man acted largely independent from external forces.

La cultura de la calidad : Aplicación e impacto de un sistema de gestión basado en las normas ISO 9001:2008 en la Biblioteca Mayor de la Universidad Nacional de Córdoba

El propósito es compartir una experiencia de gestión de la Biblioteca Mayor de la Universidad Nacional de Córdoba, a través de la implementación de las normas ISO 9001: 2008, adoptando una nueva filosofía comprometida con los principios de la calidad y en la optimización del aprendizaje organizacional, orientado a dar respuestas a las necesidades de los usuarios por medio de servicios basados en innovaciones tecnológicas y bibliotecológicas. Este trabajo se basa en un estudio de caso describiendo los componentes del sistema, enriquecido con aportes de entrevistas personalizadas pertenecientes a distintos sectores involucrados con el proceso de certificación de la Biblioteca. Se analizan los obstáculos encontrados y los logros obtenidos basados en la mejora continua de los servicios. La obtención de una certificación no constituye un fin, sino es el comienzo de un proceso constructivo enmarcado en una cultura de la calidad, con una dinámica nueva de gestión que permite evaluar lo que se hace y como se hace.

La cultura de la calidad : Aplicación e impacto de un sistema de gestión basado en las normas ISO 9001:2008 en la Biblioteca Mayor de la Universidad Nacional de Córdoba

El propósito es compartir una experiencia de gestión de la Biblioteca Mayor de la Universidad Nacional de Córdoba, a través de la implementación de las normas ISO 9001: 2008, adoptando una nueva filosofía comprometida con los principios de la calidad y en la optimización del aprendizaje organizacional, orientado a dar respuestas a las necesidades de los usuarios por medio de servicios basados en innovaciones tecnológicas y bibliotecológicas. Este trabajo se basa en un estudio de caso describiendo los componentes del sistema, enriquecido con aportes de entrevistas personalizadas pertenecientes a distintos sectores involucrados con el proceso de certificación de la Biblioteca. Se analizan los obstáculos encontrados y los logros obtenidos basados en la mejora continua de los servicios. La obtención de una certificación no constituye un fin, sino es el comienzo de un proceso constructivo enmarcado en una cultura de la calidad, con una dinámica nueva de gestión que permite evaluar lo que se hace y como se hace.

La cultura de la calidad : Aplicación e impacto de un sistema de gestión basado en las normas ISO 9001:2008 en la Biblioteca Mayor de la Universidad Nacional de Córdoba

El propósito es compartir una experiencia de gestión de la Biblioteca Mayor de la Universidad Nacional de Córdoba, a través de la implementación de las normas ISO 9001: 2008, adoptando una nueva filosofía comprometida con los principios de la calidad y en la optimización del aprendizaje organizacional, orientado a dar respuestas a las necesidades de los usuarios por medio de servicios basados en innovaciones tecnológicas y bibliotecológicas. Este trabajo se basa en un estudio de caso describiendo los componentes del sistema, enriquecido con aportes de entrevistas personalizadas pertenecientes a distintos sectores involucrados con el proceso de certificación de la Biblioteca. Se analizan los obstáculos encontrados y los logros obtenidos basados en la mejora continua de los servicios. La obtención de una certificación no constituye un fin, sino es el comienzo de un proceso constructivo enmarcado en una cultura de la calidad, con una dinámica nueva de gestión que permite evaluar lo que se hace y como se hace.

Pollen record from Blankensee, Germany

Lake Blankensee is filled with 14 m of late- and postglacial deposits, Lake Siethener See with 22,5 m. The lacustrine sedimentation begins in Lake Siethener See in the middle of the Alleröd with annual lamination which partly continues in the Younger Dryas. A 2 cm thick layer of the Laacher See tephra was found in both lakes, the Saksunarvatn tephra only in Lake Siethener See where the cool Rammelbeek-phase (Preboreal) could be shown. The youngest part of the sediment profiles is suspended drifting mud. Masses of Pediastrum (algae) indicate an increasing shoaling of Lake Blankensee after the Subboreal.

(Appendix) Vertebral number of topsmelt, Atherinops affinis, adults and offspring from different latitudes along the North-American Pacific coast

Organisms that are distributed across spatial climate gradients often exhibit adaptive local variations in morphological and physiological traits, but to what extent such gradients shape evolutionary responses is still unclear. Given the strong natural contrast in latitudinal temperature gradients between the North-American Pacific and Atlantic coast, we asked how increases in vertebral number (VN, known as Jordan's Rule) with latitude would differ between Pacific (Atherinops affinis) and Atlantic Silversides (Menidia menidia), two ecologically equivalent and taxonomically similar fishes with similar latitudinal distributions. VN was determined from radiographs of wild-caught adults (genetic + environmental differences) and its genetic basis confirmed by rearing offspring in common garden experiments. Compared to published data on VN variation in M. menidia (a mean increase of 7.0 vertebrae from 32 to 46°N, VN slope = 0.42/lat), the latitudinal VN increase in Pacific Silversides was approximately half as strong (a mean increase of 3.3 vertebrae from 28 to 43°N, VN slope = 0.23/lat). This mimicked the strong Atlantic (1.11°C/lat) versus weak Pacific latitudinal gradient (0.40°C/lat) in median annual sea surface temperature (SST). Importantly, the relationship of VN to SST was not significantly different between the two species (average slope = -0.39 vertebrae/°C), thus suggesting a common thermal dependency of VN in silverside fishes. Our findings provide novel support for the hypothesis that temperature gradients are the ultimate cause of Jordan's Rule, even though its exact adaptive significance remains speculative. A second investigated trait, the mode of sex determination in Atlantic versus Pacific Silversides, revealed patterns that were inconsistent with our expectation: M. menidia displays temperature-dependent sex determination (TSD) at low latitudes, where growing seasons are long or unconstrained, but also a gradual shift to genetic sex determination (GSD) with increasing latitude due to more and more curtailed growing seasons. Sex ratios in A. affinis, on the other hand, were independent of latitude and rearing temperature (indicating GSD), even though growing seasons are thermally unconstrained across most of the geographical distribution of A. affinis. This suggests that additional factors (e.g., longevity) play an important role in shaping the mode of sex determination in silverside fishes.