bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure of organo-bentonites in water and the effect of steric hindrance on the uptake of organic compounds
Authors: Zhu Jianxi , Zhu Lizhong , Zhu Runliang , Chen Baoliang
Published: May 2008

To further elucidate adsorption-to-partition transitional mechanisms which have been proposed previously for organo-bentonites with different surfactant loadings, the structural characteristics of interlayer surfactant aggregates on organo-bentonite with different surfactant cetyltrimethylammonium bromide loading levels (0.20–2.56 times cation exchange capacity, CEC) have been investigated by in situ X-ray diffraction (XRD) and Fourier TransformInfrared (FTIR) spectroscopy. The sorption properties and the structure of the clay interlayers changed according to the type of surfactant, the surfactant loading level, and the state of hydration in the clays. Based on the sorption of nitrobenzene, phenol, and aniline to organobentonites, the contaminant sorption coefficients (Ksf), normalized with the organic carbon content, show a remarkable dependence on surfactant loading levels. The Ksf values first increased with surfactant loading until reaching a maximum at 1.0 to 1.2 times the CEC, and then decreased. According to the theoretical calculation of the volume fractions relating to the interlamellar space, the interlamellar microenvironment became a more hydrophobic medium, contributing to the dissolution of organic contaminants, as the surfactant loading increased from 0.20 to 2.56 times the CEC. However, the increase in packing density (ρ) for the intercalates, and induced steric hindrances both affect the result in terms of a reduction in the accessible free space where the organic contaminants can be located, which might be a negative factor in the sorption capacity.
Diffusion of Na and Cs in montmorillonite
Authors: Kosakowski Georg , Churakov Sergey V. , Thoenen Tres
Published: May 2008

The state and dynamics of water and cations in pure and mixed Na-Cs-montmorillonite as a function of the interlayer water content were investigated in the present study, using Monte Carlo and classical, molecular-dynamics methods. While highly idealized, the simulations showed that the swelling behavior of hetero-ionic Na-Cs-montmorillonite is comparable to the swelling of a homo-ionic Na- or Cs-montmorillonite. The mixed Na-Cs-montmorillonite is characterized by intermediate interlayer distances compared to homo-ionic Na- and Cs-montmorillonites. Dry, hetero-ionic Na-Cs-montmorillonite is characterized by a symmetric sheet configuration, as is homo-ionic Cs-montmorillonite.

We found that at low degrees of hydration the absolute diffusion coefficient of Cs+ is less than for Na+, whereas at greater hydration states the diffusion coefficient of Cs+ is greaterthan for Na+. An analysis of the relative diffusion coefficients (the ratio between the diffusion coefficient of an ion in the interlayer and its diffusion coefficient in bulk water) revealed that water and Na+ are always less retarded than Cs+. With large interlayer water contents, tetralayer or more, Na+ ions preferentially form outer-sphere complexes. The mobility perpendicular to the clay surface is limited and the diffusion is equivalent to two-dimensional diffusion in bulk water. In contrast, Cs+ ions preferentially form ‘inner-sphere complexes’ at all hydration states and their two-dimensional diffusion coefficient is less than in bulk water.

The question remains unanswered as to why experimentally derived relative diffusion coefficients of Cs+ in the interlayer of clays are about 20 times less than those we obtained by classical molecular dynamics studies.
The occurrence and genesis of clay minerals associated with Quaternary caliches in the Mersin area, southern Turkey
Authors: Kadir Selahattin , Eren Muhsin
Published: May 2008

Caliche in various forms, namely powdery, nodule, tube, fracture-infill, laminar crust, hard laminated crust (hardpan), and pisolitic crust, is widespread in the Mersin area in southern Turkey. It generally occurs within and/or over the reddish-brown mudstone of the Kuzgun Formation (Tortonian, Miocene) and alluvial red soils of the Quaternary. The mineralogical distribution along representative caliche profiles was examined by X-ray diffraction, scanning electron microscopy, differential thermal analysis-thermal gravimetry, and chemical techniques. Calcite is the most abundant mineral associated with minor amounts of palygorskite in caliche samples, whereas smectite is prevalent mainly in the reddish-brown mudstone and alluvial red soils of the caliche parent materials and is associated with appreciable amounts of palygorskite. These minerals are also accompanied by trace amount of illite, quartz, feldspar, and a poorly crystalline phase. Palygorskite fibers and fiber bundles were developed authigenically on euhedral or subhedral calcite crystals of the caliche units and at the edges of smectite flakes in the caliche host-rocks or sediments. Intense, continuous evaporation of subsurface soil-water resulted in an increase in pH and the dissolution of detrital smectite within the red mudstones and alluvial red soils that enclose the isolated caliche forms, and caused an increase in the Al+Fe and Mg/Ca ratio, favoring the formation of palygorskite under alkaline conditions. The calcium required for caliche formation may have originated from eolian dust, detrital carbonate minerals, and/or other caliche materials, which are dissolved by carbonic acid.
Twisted McFarland and Spence designs and their automorphisms
Authors: Dempwolff Ulrich
Published: May 2008

In this note we construct symmetric designs which have the parameters of McFarland or Spence designs and whose full automorphism groups are isomorphic to an arbitrarily preassigned finite group.
Planar compact sets whose intersections are starshaped via orthogonally convex paths
Authors: Breen Marilyn
Published: May 2008

A Helly-type theorem previously established for a finite family of simply connected orthogonal polygons may be extended to a family of planar compact sets having connected complements: If every three (not necessarily distinct) members of have a nonempty intersection that is starshaped via orthogonally convex paths, then all members of have such an intersection. When is finite, an analogous result holds with orthogonally convex paths replaced by staircase paths. The number three is best possible in each case. Moreover, the results fail without the requirement that the sets have connected complements.
On arithmetic Zariski pairs in degree 6
Authors: Shimada Ichiro
Published: May 2008

We define a topological invariant of complex projective plane curves. As an application, we present new examples of arithmetic Zariski pairs.
Defect and Hodge numbers of hypersurfaces
Authors: Rams Sławomir
Published: May 2008

We define defect for hypersurfaces with A-D-E singularities in complex projective normal Cohen–Macaulay fourfolds having some vanishing properties of Bott-type and prove formulae for Hodge numbers of big resolutions of such hypersurfaces. We compute Hodge numbers of Calabi–Yau manifolds obtained as small resolutions of cuspidal triple sextics and double octics with higher A
j
singularities.
Diplopsalopsis kisselevii sp. nov. (Dinophyceae) from the northwestern Sea of Japan
Authors: Selina Marina S. , Konovalova Galina V. , Begun Andrey A. , Morozova Tatiana V.
Published: May 2008

A new species of the genus Diplopsalopsis, D. kisselevii sp. nov., was found in Amursky Bay off the northwestern coast of the Sea of Japan. This species combines the Diplopsalopsis plate pattern with a protoperidinoid shape. The plate tabulation is Po, X, 3′, 2a, 7″, 4c, 4s, 5′″, 2″″. Cells are oval or almost rounded, slightly longer than wide and slightly flattened dorso-ventrally, 34–48 μm long and 34–46 μm wide. The length/width ratio is 1.0–1.05. The epitheca is slightly shorter than the hypotheca. The cingular list is very narrow, smooth and without ribs. The left sulcal list is narrow and short. The apical sunken depression of the theca contains the comma-like pore complex. Two intercalary plates are present. The narrow, long and hexagonal 1a contacts the 2′, 1″, 2″, 3″, 4″, and 2a plates. The large pentagonal 2a is positioned on the dorsal side of the epitheca with no contact to the Po plate. Diplopsalopsis kisselevii sp. nov. is similar to D. latipeltata in cell shape, and possesses reduced cingular and left sulcal lists and a long intercalary plate. However, D. kisselevii can be differentiated from D. latipeltata by the structure of the theca, the tabulation formula of the epitheca, and the shape, size and position of the anterior intercalary 1a plate.
Growth and reproductive phenology of Pterocladiella capillacea (Rhodophyta: Gelidiales) from the southern Adriatic Sea
Authors: Bottalico Antonella , Delle Foglie Costanza Ilaria , Fanelli Margherita
Published: May 2008

Growth, external morphology and reproductive phenology of a southern Adriatic population of Pterocladiella capillacea from a marine cave were investigated. Production of new uprights from creeping axes was limited to late autumn–winter; upright growth in length and branching order increase reached their maxima in late summer. Tetrasporic fronds were dominant from June to September, with a peak in July, while cystocarpic uprights were rather rare and recorded in August only. Two stable, distinct morphotypes occurred in this population at two sampling sites exposed to different daily photon irradiances. Uprights from the more illuminated site were regularly pinnate, with numerous closely packed lateral branches, representing the best-known phenotype of the species; in contrast, uprights from the more shaded inner site had very long and narrow axes, greater intervals between first-order branches and lower branching order. Statistical analysis demonstrated that upright growth in length and branching was significantly different at the two sites; upright biomass in the more illuminated site was generally higher because of the higher orders of branching.
Digitizing California History: Issues of Selection and Description
Authors: Sutton Shan C.
Published: May 2008

The University of the Pacific has been a part of California history since its founding as the state's first chartered institution of higher education in 1851. In support of the University's teaching and research mission, the University Library's Special Collections department has amassed a wealth of manuscript collections and historic documents that provide valuable insights into California's rich history. Special Collections has recently undertaken digitization initiatives to expand online access to its unique holdings. This article will review these digital collections, and discuss some of the selection criteria and descriptive practices used in creating them.
Stress Impairs Reconsolidation of Drug Memory via Glucocorticoid Receptors in the Basolateral Amygdala
Authors: Wang Xiao-Yi , Zhao Mei , Ghitza Udi E. , Li Yan-Qin , Lu Lin
Published: May 2008

Relapse to drug taking induced by exposure to cues associated with drugs of abuse is a major challenge to the treatment of drug addiction. Previous studies indicate that drug seeking can be inhibited by disrupting the reconsolidation of a drug-related memory. Stress plays an important role in modulating different stages of memory including reconsolidation, but its role in the reconsolidation of a drug-related memory has not been investigated. Here, we examined the effects of stress and corticosterone on reconsolidation of a drug-related memory using a conditioned place preference (CPP) procedure. We also determined the role of glucocorticoid receptors (GRs) in the basolateral amygdala (BLA) in modulating the effects of stress on reconsolidation of this memory. We found that rats acquired morphine CPP after conditioning, and that this CPP was inhibited by stress given immediately after re-exposure to a previously morphine-paired chamber (a reconsolidation procedure). The disruptive effect of stress on reconsolidation of morphine related memory was prevented by inhibition of corticosterone synthesis with metyrapone or BLA, but not central amygdala (CeA), injections of the glucocorticoid (GR) antagonist RU38486 [(11,17)-11-[4-(dimethylamino)phenyl]-17-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one]. Finally, the effect of stress on drug related memory reconsolidation was mimicked by systemic injections of corticosterone or injections of RU28362 [11,17-dihydroxy-6-methyl-17-(1-propynyl)androsta-1,4,6-triene-3-one] (a GR agonist) into BLA, but not the CeA. These results show that stress blocks reconsolidation of a drug-related memory, and this effect is mediated by activation of GRs in the BLA.
Prefrontal–Inferotemporal Interaction Is Not Always Necessary for Reversal Learning
Authors: Wilson Charles R. E. , Gaffan David
Published: May 2008

Prefrontal cortex (PFC) is thought to have a wide-ranging role in cognition, often described as executive function or behavioral inhibition. A specific example of such a role is the inhibition of representations in more posterior regions of cortex in a “top-down” manner, a function thought to be tested by reversal learning tasks. The direct action of PFC on posterior regions can be directly tested by disconnecting PFC from the region in question. We tested whether PFC directly inhibits visual object representations in inferotemporal cortex (IT) during reversal learning by studying the effect, in macaque monkeys, of disconnecting PFC from IT by crossed unilateral ablations. We tested two visual object reversal learning tasks, namely serial and concurrent reversal learning. We found that the disconnection severely impairs serial reversal learning but leaves concurrent reversal learning completely intact. Thus, PFC cannot be said to always have direct inhibitory control over visual object representations in reversal learning. Furthermore, our results cannot be explained by generalized theories of PFC function such as executive function and behavioral inhibition, because those theories do not make predictions that differentiate different forms of reversal learning. The results do, however, support our proposal, based on other experimental evidence from macaque monkeys, that PFC has a highly specific role in the representation of temporally complex events.
Recurrent Collateral Connections of Striatal Medium Spiny Neurons Are Disrupted in Models of Parkinson's Disease
Authors: Taverna Stefano , Ilijic Ema , Surmeier D. James
Published: May 2008

The principal neurons of the striatum, GABAergic medium spiny neurons (MSNs), are interconnected by local recurrent axon collateral synapses. Although critical to many striatal models, it is not clear whether these connections are random or whether they preferentially link functionally related groups of MSNs. To address this issue, dual whole patch-clamp recordings were made from striatal MSNs in brain slices taken from transgenic mice in which D1or D2dopamine receptor expression was reported with EGFP (enhanced green fluorescent protein). These studies revealed that unidirectional connections were common between both D1receptor-expressing MSN (D1MSN) pairs (26%) and D2receptor-expressing MSN (D2MSN) pairs (36%). D2MSNs also commonly formed synapses on D1MSNs (27% of pairs). Conversely, only 6% of the D1MSNs formed detectable connections with D2MSNs. Furthermore, synaptic connections formed by D1MSNs were weaker than those formed by D2MSNs, a difference that was attributable to fewer GABAAreceptors at D1MSN synapses. The strength of detectable recurrent connections was dramatically reduced in Parkinson's disease models. The studies demonstrate that recurrent collateral connections between MSNs are not random but rather differentially couple D1and D2MSNs. Moreover, this recurrent collateral network appears to be disrupted in Parkinson's disease models, potentially contributing to pathological alterations in MSN activity patterns and psychomotor symptoms.
Vietnam's Security Objectives in Mekong Basin Governance
Authors: Hensengerth Oliver
Published: May 2008

The paper examines Vietnam's foreign policy as it translates into strategies toward subregional cooperation in the Mekong Basin. Using transboundary water cooperation as an example, the article argues that Vietnam's prime motivation in Mekong River cooperation is economic development for performance legitimacy. Environmental issues are raised, but only in relation to powerful upstream countries, while Vietnam itself poses similar challenges to less powerful downstream countries. The need for performance legitimacy thus conveys all relevance to the economically oriented Greater Mekong Subregion, while the Mekong River Commission, a basin organization with a mandate to combine economic development with environmental considerations, is sidelined.
Fate, Memory, and the Postcolonial Construction of the Self: The Life-Narrative of a Vietnamese Spirit Medium
Authors: Endres Kirsten W.
Published: May 2008

Life-history and narrative research have a long tradition as insightful methods in anthropology. This article presents the life-story of an elderly Hanoian spirit medium who does not conform to dominant ideals of Vietnamese femininity, exploring how cultural concepts and religious imageries shape female notions of fate and agency. By applying Bakhtin's concept of dialogism, the analysis illustrates how the creative act of self-narrative interweaves with multiple discourses in a dialogic process that tries to make sense of historical contingencies, culturally prescribed ideals, and the lived experiences of the self.
The Stochastic Edge in Adaptive Evolution
Authors: Brunet Éric , Rouzine Igor M , Wilke Claus O
Published: May 2008

In a recent article, Desai and Fisher proposed that the speed of adaptation in an asexual population is determined by the dynamics of the stochastic edge of the population, that is, by the emergence and subsequent establishment of rare mutants that exceed the fitness of all sequences currently present in the population. Desai and Fisher perform an elaborate stochastic calculation of the mean time τ until a new class of mutants has been established and interpret 1/τ as the speed of adaptation. As they note, however, their calculations are valid only for moderate speeds. This limitation arises from their method to determine τ: Desai and Fisher back extrapolate the value of τ from the best-fit class's exponential growth at infinite time. This approach is not valid when the population adapts rapidly, because in this case the best-fit class grows nonexponentially during the relevant time interval. Here, we substantially extend Desai and Fisher's analysis of the stochastic edge. We show that we can apply Desai and Fisher's method to high speeds by either exponentially back extrapolating from finite time or using a nonexponential back extrapolation. Our results are compatible with predictions made using a different analytical approach (Rouzine et al.) and agree well with numerical simulations.
Statistical Power Analysis of Neutrality Tests Under Demographic Expansions, Contractions and Bottlenecks With Recombination
Authors: Ramírez-Soriano Anna , Ramos-Onsins Sebastià E , Rozas Julio , Calafell Francesc , Navarro Arcadi
Published: May 2008

Several tests have been proposed to detect departures of nucleotide variability patterns from neutral expectations. However, very different kinds of evolutionary processes, such as selective events or demographic changes, can produce similar deviations from these tests, thus making interpretation difficult when a significant departure of neutrality is detected. Here we study the effects of demography and recombination upon neutrality tests by analyzing their power under sudden population expansions, sudden contractions, and bottlenecks. We evaluate tests based on the frequency spectrum of mutations and the distribution of haplotypes and explore the consequences of using incorrect estimates of the rates of recombination when testing for neutrality. We show that tests that rely on haplotype frequencies—especially Fs and ZnS, which are based, respectively, on the number of different haplotypes and on the r2 values between all pairs of polymorphic sites—are the most powerful for detecting expansions on nonrecombining genomic regions. Nevertheless, they are strongly affected by misestimations of recombination, so they should not be used when recombination levels are unknown. Instead, class I tests, particularly Tajima's D or R2, are recommended.
Genomic Analysis of Adaptive Differentiation inDrosophila melanogaster
Authors: Turner Thomas L , Levine Mia T , Eckert Melissa L , Begun David J
Published: May 2008

Drosophila melanogaster shows clinal variation along latitudinal transects on multiple continents for several phenotypes, allozyme variants, sequence variants, and chromosome inversions. Previous investigation suggests that many such clines are due to spatially varying selection rather than demographic history, but the genomic extent of such selection is unknown. To map differentiation throughout the genome, we hybridized DNA from temperate and subtropical populations to Affymetrix tiling arrays. The dense genomic sampling of variants and low level of linkage disequilibrium in D. melanogaster enabled identification of many small, differentiated regions. Many regions are differentiated in parallel in the United States and Australia, strongly supporting the idea that they are influenced by spatially varying selection. Genomic differentiation is distributed nonrandomly with respect to gene function, even in regions differentiated on only one continent, providing further evidence for the role of selection. These data provide candidate genes for phenotypes known to vary clinally and implicate interesting new processes in genotype-by-environment interactions, including chorion proteins, proteins regulating meiotic recombination and segregation, gustatory and olfactory receptors, and proteins affecting synaptic function and behavior. This portrait of differentiation provides a genomic perspective on adaptation and the maintenance of variation through spatially varying selection.
Control of Antagonistic Components of the Hedgehog Signaling Pathway by microRNAs in Drosophila
Authors: Friggi-Grelin Florence , Lavenant-Staccini Laurence , Therond Pascal
Published: May 2008

Hedgehog (Hh) signaling is critical for many developmental processes and for the genesis of diverse cancers. Hh signaling comprises a series of negative regulatory steps, from Hh reception to gene transcription output. We previously showed that stability of antagonistic regulatory proteins, including the coreceptor Smoothened (Smo), the kinesin-like Costal-2 (Cos2), and the kinase Fused (Fu), is affected by Hh signaling activation. Here, we show that the level of these three proteins is also regulated by a microRNA cluster. Indeed, the overexpression of this cluster and resulting microRNA regulation of the 3′-UTRs of smo, cos2, and fu mRNA decreases the levels of the three proteins and activates the pathway. Further, the loss of the microRNA cluster or of Dicer function modifies the 3′-UTR regulation of smo and cos2 mRNA, confirming that the mRNAs encoding the different Hh components are physiological targets of microRNAs. Nevertheless, an absence of neither the microRNA cluster nor of Dicer activity creates an hh-like phenotype, possibly due to dose compensation between the different antagonistic targets. This study reveals that a single signaling pathway can be targeted at multiple levels by the same microRNAs.
Population Structure and Inbreeding From Pedigree Analysis of Purebred Dogs
Authors: Calboli Federico C F , Sampson Jeff , Fretwell Neale , Balding David J
Published: May 2008

Dogs are of increasing interest as models for human diseases, and many canine population-association studies are beginning to emerge. The choice of breeds for such studies should be informed by a knowledge of factors such as inbreeding, genetic diversity, and population structure, which are likely to depend on breed-specific selective breeding patterns. To address the lack of such studies we have exploited one of the world's most extensive resources for canine population-genetics studies: the United Kingdom (UK) Kennel Club registration database. We chose 10 representative breeds and analyzed their pedigrees since electronic records were established around 1970, corresponding to about eight generations before present. We find extremely inbred dogs in each breed except the greyhound and estimate an inbreeding effective population size between 40 and 80 for all but 2 breeds. For all but 3 breeds, >90% of unique genetic variants are lost over six generations, indicating a dramatic effect of breeding patterns on genetic diversity. We introduce a novel index Ψ for measuring population structure directly from the pedigree and use it to identify subpopulations in several breeds. As well as informing the design of canine population genetics studies, our results have implications for breeding practices to enhance canine welfare.
Genome Analysis of the Unicellular Green Alga Chlamydomonas reinhardtii Indicates an Ancient Evolutionary Origin for Key Pattern Recognition and Cell-Signaling Protein Families
Authors: Wheeler Glen L , Miranda-Saavedra Diego , Barton Geoffrey J
Published: May 2008

The evolution of specific cell signaling and adhesion domains may have played an important role in the transition to a multicellular existence in the metazoans. Genomic analysis indicates that several signaling domains predominately found in animals are also present in the unicellular green alga, Chlamydomonas reinhardtii. A large group of proteins is present, containing scavenger receptor cysteine-rich (SRCR) and C-type lectin domains, which function in ligand binding and play key roles in the innate immune system of animals. Chlamydomonas also contains a large family of putative tyrosine kinases, suggesting an important role for phosphotyrosine signaling in the green algae. These important signaling domains may therefore be widespread among eukaryotes and most probably evolved in ancestral eukaryotes before the divergence of the Opisthokonts (the animal and fungal lineage).
Genome Analysis of Chlamydomonas reinhardtii Reveals The Existence of Multiple, Compartmentalized Iron–Sulfur Protein Assembly Machineries of Different Evolutionary Origins
Authors: Godman James , Balk Janneke
Published: May 2008

The unicellular green alga Chlamydomonas reinhardtii is used extensively as a model to study eukaryotic photosynthesis, flagellar functions, and more recently the production of hydrogen as biofuel. Two of these processes, photosynthesis and hydrogen production, are highly dependent on iron–sulfur (Fe–S) enzymes. To understand how Fe–S proteins are assembled in Chlamydomonas, we have analyzed its recently sequenced genome for orthologs of genes involved in Fe–S cluster assembly. We found a total of 32 open reading frames, most single copies, that are thought to constitute a mitochondrial assembly pathway, mitochondrial export machinery, a cytosolic assembly pathway, and components for Fe–S cluster assembly in the chloroplast. The chloroplast proteins are also expected to play a role in the assembly of the H-cluster in [FeFe]-hydrogenases, together with the recently identified HydEF and HydG proteins. Comparison with the higher plant model Arabidopsis indicated a strong degree of conservation of Fe–S cofactor assembly pathways in the green lineage, the pathways being derived from different origins during the evolution of the photosynthetic eukaryote. As a haploid, unicellular organism with available forward and reverse genetic tools, Chlamydomonas provides an excellent model system to study Fe–S cluster assembly and its regulation in photosynthetic eukaryotes.
Green Transcription Factors: A Chlamydomonas Overview
Authors: Riaño-Pachón Diego Mauricio , Corrêa Luiz Gustavo Guedes , Trejos-Espinosa Raúl , Mueller-Roeber Bernd
Published: May 2008

Transcription factors (TFs) control gene expression by interacting with cis-elements in target gene promoters. Transcription regulators (TRs) assist in controlling gene expression through interaction with TFs, chromatin remodeling, or other mechanisms. Both types of proteins thus constitute master controllers of dynamic transcriptional networks. To uncover such control elements in the photosynthetic green alga Chlamydomonas reinhardtii, we performed a comprehensive analysis of its genome sequence. In total, we identified 234 genes encoding 147 TFs and 87 TRs of ∼40 families. The set of putative TFs and TRs, including their transcript and protein sequences, domain architectures, and supporting information about putative orthologs, is available at http://plntfdb.bio.uni-potsdam.de/v2.0/. Twelve of 34 plant-specific TF families were found in at least one algal species, indicating their early evolutionary origin. Twenty-two plant-specific TF families and one plant-specific TR family were not observed in algae, suggesting their specific association with developmental or physiological processes characteristic to multicellular plants. We also analyzed the occurrence of proteins that constitute the light-regulated transcriptional network in angiosperms and found putative algal orthologs for most of them. Our analysis provides a solid ground for future experimental studies aiming at deciphering the transcriptional regulatory networks in green algae.
Diversification of the Core RNA Interference Machinery in Chlamydomonas reinhardtii and the Role of DCL1 in Transposon Silencing
Authors: Casas-Mollano J Armando , Rohr Jennifer , Kim Eun-Jeong , Balassa Eniko , van Dijk Karin , Cerutti Heriberto
Published: May 2008

Small RNA-guided gene silencing is an evolutionarily conserved process that operates by a variety of molecular mechanisms. In multicellular eukaryotes, the core components of RNA-mediated silencing have significantly expanded and diversified, resulting in partly distinct pathways for the epigenetic control of gene expression and genomic parasites. In contrast, many unicellular organisms with small nuclear genomes seem to have lost entirely the RNA-silencing machinery or have retained only a basic set of components. We report here that Chlamydomonas reinhardtii, a unicellular eukaryote with a relatively large nuclear genome, has undergone extensive duplication of Dicer and Argonaute polypeptides after the divergence of the green algae and land plant lineages. Chlamydomonas encodes three Dicers and three Argonautes with DICER-LIKE1 (DCL1) and ARGONAUTE1 being more divergent than the other paralogs. Interestingly, DCL1 is uniquely involved in the post-transcriptional silencing of retrotransposons such as TOC1. Moreover, on the basis of the subcellular distribution of TOC1 small RNAs and target transcripts, this pathway most likely operates in the nucleus. However, Chlamydomonas also relies on a DCL1-independent, transcriptional silencing mechanism(s) for the maintenance of transposon repression. Our results suggest that multiple, partly redundant epigenetic processes are involved in preventing transposon mobilization in this green alga.
A New Purple Fluorescent Color Marker for Genetic Studies inSaccharomyces cerevisiaeandCandida albicans
Authors: Keppler-Ross Sabine , Noffz Christine , Dean Neta
Published: May 2008

The ability to visualize cellular events by linking them to color or fluorescence changes has been an invaluable tool for biology. We describe a novel plasmid-borne color marker whose expression in yeast leads to purple-colored cells that are also brightly fluorescent. This dominant marker provides a useful tool for rapidly screening plasmid maintenance using a visual or fluorescence assay in both Saccharomyces cerevisiae and Candida albicans.
Reconstructing the Mitochondrial Protein Import Machinery of Chlamydomonas reinhardtii
Authors: Figueroa-Martínez Francisco , Funes Soledad , Franzén Lars-Gunnar , González-Halphen Diego
Published: May 2008

In Chlamydomonas reinhardtii several nucleus-encoded proteins that participate in the mitochondrial oxidative phosphorylation are targeted to the organelle by unusually long mitochondrial targeting sequences. Here, we explored the components of the mitochondrial import machinery of the green alga. We mined the algal genome, searching for yeast and plant homologs, and reconstructed the mitochondrial import machinery. All the main translocation components were identified in Chlamydomonas as well as in Arabidopsis thaliana and in the recently sequenced moss Physcomitrella patens. Some of these components appear to be duplicated, as is the case of Tim22. In contrast, several yeast components that have relatively large hydrophilic regions exposed to the cytosol or to the intermembrane space seem to be absent in land plants and green algae. If present at all, these components of plants and algae may differ significantly from their yeast counterparts. We propose that long mitochondrial targeting sequences in some Chlamydomonas mitochondrial protein precursors are involved in preventing the aggregation of the hydrophobic proteins they carry.
Metabolomics- and Proteomics-Assisted Genome Annotation and Analysis of the Draft Metabolic Network of Chlamydomonas reinhardtii
Authors: May Patrick , Wienkoop Stefanie , Kempa Stefan , Usadel Björn , Christian Nils , Rupprecht Jens , Weiss Julia , Recuenco-Munoz Luis , Ebenhöh Oliver , Weckwerth Wolfram , Walther Dirk
Published: May 2008

We present an integrated analysis of the molecular repertoire of Chlamydomonas reinhardtii under reference conditions. Bioinformatics annotation methods combined with GCxGC/MS-based metabolomics and LC/MS-based shotgun proteomics profiling technologies have been applied to characterize abundant proteins and metabolites, resulting in the detection of 1069 proteins and 159 metabolites. Of the measured proteins, 204 currently do not have EST sequence support; thus a significant portion of the proteomics-detected proteins provide evidence for the validity of in silico gene models. Furthermore, the generated peptide data lend support to the validity of a number of proteins currently in the proposed model stage. By integrating genomic annotation information with experimentally identified metabolites and proteins, we constructed a draft metabolic network for Chlamydomonas. Computational metabolic modeling allowed an identification of missing enzymatic links. Some experimentally detected metabolites are not producible by the currently known and annotated enzyme set, thus suggesting entry points for further targeted gene discovery or biochemical pathway research. All data sets are made available as supplementary material as well as web-accessible databases and within the functional context via the Chlamydomonas-adapted MapMan annotation platform. Information of identified peptides is also available directly via the JGI-Chlamydomonas genomic resource database (http://genome.jgi-psf.org/Chlre3/Chlre3.home.html).
The status of the name Alysium holtingii C. Agardh, a red alga described from Brazil, and a depiction of the type specimen
Authors: Wynne Michael J.
Published: May 2008

The type specimen of the red alga Alysium holtingii C. Agardh, described from Brazil, is located in the Lund Herbarium, and it is depicted for the first time in a publication. It is taxonomically identical to Dichotomaria obtusata (J. Ellis and Solander) Lamarck and thus can be treated as a later taxonomic synonym. Alysium is regarded as congeneric with Dichotomaria.
Geochemistry and petrogenesis of post-collisional ultrapotassic syenites and granites from southernmost Brazil: the Piquiri Syenite Massif
Authors: Nardi Lauro V.S. , Plá-Cid Jorge , Bitencourt Maria de Fátima , Stabel Larissa Z.
Published: May 2008

The Piquiri Syenite Massif, southernmost Brazil, is part of the post-collisional magmatism related to the Neoproterozoic Brasiliano-Pan-African Orogenic Cycle. The massif is about 12 km in diameter and is composed of syenites, granites, monzonitic rocks and lamprophyres. Diopside-phlogopite, diopside-biotite-augite-calcic-amphibole, are the main ferro-magnesian paragenesis in the syenitic rocks. Syenitic and granitic rocks are co-magmatic and related to an ultrapotassic, silica-saturated magmatism. Their trace element patterns indicate a probable mantle source modified by previous, subduction-related metasomatism. The ultrapotassic granites of this massif were produced by fractional crystallization of syenitic magmas, and may be considered as a particular group of hypersolvus and subsolvus A-type granites. Based upon textural, structural and geochemical data most of the syenitic rocks, particularly the fine-grained types, are considered as crystallized liquids, in spite of the abundance of cumulatic layers, schlieren, and compositional banding. Most of the studied samples are metaluminous, with K2O/Na2O ratios higher than 2. The ultrapotassic syenitic and lamprophyric rocks in the Piquiri massif are interpreted to have been produced from enriched mantle sources, OIB-type, like most of the post-collisional shoshonitic, sodic alkaline and high-K tholeiitic magmatism in southernmost Brazil. The source of the ultrapotassic and lamprophyric magmas is probably the same veined mantle, with abundant phlogopite + apatite + amphibole that reflects a previous subduction-related metasomatism.
Fatores de risco para retinopatia diabética
Authors: Esteves Jorge , Laranjeira Andréia F. , Roggia Murilo F. , Dalpizol Melissa , Scocco Caio , Kramer Caroline K. , Azevedo Mirela J. , Canani Luís H.
Published: May 2008

A retinopatia diabética (RD) acomete cerca de 95% dos pacientes com diabetes melito tipo 1 (DM1) e 60% dos pacientes com diabetes melito tipo 2 (DM2), sendo a principal causa de cegueira legal em adultos. O objetivo desse manuscrito foi revisar os principais fatores de risco para RD. Os fatores de risco ambientais mais importantes são a hiperglicemia sustentada, os valores elevados de pressão arterial e a longa duração de DM. Entretanto, nem todos os pacientes desenvolvem RD, o que sugere a presença de fatores genéticos, em especial para as formas graves de RD. Diferentes estratégias têm sido utilizadas para avaliar o papel da genética na RD. Estudos de famílias demonstraram agregação familiar de RD. Genes candidatos têm sido estudados (RAGE; VEGF; PPAR-delta; ICAM-1; ECA; ENPP 1; eNOS), observando-se associações positivas ou negativas com a RD. Também alguns cromossomos, em populações selecionadas, foram associados à RD. Finalmente, estudos de expressão genética reforçam a associação de genes candidatos, ou determinam a participação de outros, com a presença da RD. A RD é uma complicação freqüente do DM e junto com os fatores não-genéticos ou ambientais, a identificação de genes relacionados à RD poderá resultar tratamentos mais específicos e eficazes para a RD.
Detecção precoce da nefropatia diabética
Authors: Murussi Marcia , Murussi Nádia , Campagnolo Nicole , Silveiro Sandra Pinho
Published: May 2008

Em virtude do prognóstico desfavorável das fases avançadas da nefropatia diabética (ND), o ideal é identificar o envolvimento renal de maneira precoce. A recomendação é a medida anual da excreção urinária de albumina (EUA), em amostras de urina casual, para detectar os estágios da ND [microalbuminúria (EUA 17-174 mg/l ou 30 a 300 mg albumina/g de creatinina) e macroalbuminúria (> 174 mg/l ou > 300 mg/g)]. No entanto, tem sido sugerido que níveis de EUA abaixo dos de consenso já seriam indicativos de risco de progressão renal e de mortalidade aumentada, devendo ser revisados esses pontos de corte. Uma quantidade expressiva da EUA, a fração não imunorreativa, não é detectada pelos métodos convencionais, e HPLC poderá ser mais sensível para identificar dano renal, medindo EUA total (imuno + não-imunorreativa). Outra observação recente é a presença de diminuição da taxa de filtração glomerular (TFG) mesmo em normoalbuminúricos. Portanto, além da EUA, recomenda-se estimar a TFG com equação empregando creatinina, como a do estudo Modification of Diet in Renal Disease (MDRD), disponível em www.mdrd.com. Em razão das conhecidas limitações da creatinina, marcadores endógenos alternativos estão em investigação, sendo a cistatina C um marcador promissor. Finalmente, novas estratégias que poderão ser ainda mais precoces para detecção da ND incluem biomarcadores, como proteoma, definindo um perfil de proteínas urinárias que identifiquem risco subseqüente de doença renal.
Avaliação da prevalência do diabetes e da hiperglicemia de estresse no infarto agudo do miocárdio
Authors: Lerario Antonio Carlos , Coretti Fabiana M. L. Martins , Oliveira Sergio Ferreira de , Betti Roberto Tadeu Barcelos , Bastos Maria do Socorro C. B. , Ferri Letícia de Araujo Funari , Garcia Rosa Maria Rahmi , Wajchenberg Bernardo Leo
Published: May 2008

OBJETIVOS: Determinar a prevalência do diabetes melito (DM) e da hiperglicemia de estresse (HE) em pacientes com infarto agudo do miocárdio (IAM) admitidos em unidade de emergência cardiológica. MÉTODOS: Análise retrospectiva de 2.262 pacientes com IAM, avaliando, além da prevalência de diabetes referido, o diagnosticado e a hiperglicemia de estresse. RESULTADOS: Apesar de referido em 12,1% dos pacientes (H: 10,7%, M: 15,8%), o DM ocorria efetivamente em 24,8% (H: 22,9%, M: 29,7%) e a HE em 13,6% (H: 14,3%, M: 11,7%) dos indivíduos dessa população. Portanto, alterações glicêmicas ocorreram em 37,4% dos indivíduos com IAM (H: 37,2%, M: 41,4%). Nos pacientes com DM, observou-se maior precocidade etária do IAM, maior prevalência de óbitos (DM: 20,7%, ND:13,8%, HE: 13,4%) e de procedimentos cirúrgicos (ND: 33,8%, HE: 18,0%, DM: 21,7%). CONCLUSÃO: A elevada prevalência de DM e hiperglicemia de estresse observada em nosso estudo indica que as alterações glicêmicas constituem um dos mais importantes fatores de risco para o IAM.
Interferência do controle glicêmico na transição entre as fases I e II da lactogênese em pacientes com diabetes melito tipo 1
Authors: Oliveira Angela M. de Morais , Cunha Cleine Chagas da , Penha-Silva Nilson , Abdallah Vânia Olivetti Steffen , Jorge Paulo Tannus
Published: May 2008

A lactogênese é constituída pelas fases designadas como I e II. A transição entre essas fases é caracterizada pelo aumento da concentração de lactose no colostro. Este estudo teve como objetivo analisar a interferência do diabetes melito tipo 1 (DM1) na transição entre as fases da lactogênese. A concentração de lactose foi determinada em amostras de colostro de 11 puérperas portadoras de DM1 e de 19 puérperas sem a doença, durante os cinco primeiros dias do puerpério. A determinação da concentração da lactose foi feita pela reação com ácido pícrico. Em ambos os grupos houve aumento progressivo da concentração da lactose em função do tempo; entretanto, o aumento foi significativamente menor no terceiro e no quinto dia no grupo das portadoras de diabetes. A análise da transição de fases da lactogênese revelou que as puérperas portadoras de diabetes melito com controle glicêmico inadequado apresentaram atraso de 18 horas para alcançar a fase II da lactogênese, dificultando o estabelecimento do aleitamento materno.
Tradução para o português e validação do instrumento Diabetes Quality of Life Measure (DQOL-Brasil)
Authors: Correr Cassyano Januário , Pontarolo Roberto , Melchiors Ana Carolina , Rossignoli Paula , Fernández-Llimós Fernando , Radominski Rosana Bento
Published: May 2008

OBJETIVO: Avaliar as propriedades psicométricas da versão brasileira do questionário de medida da qualidade de vida em diabetes (DQOL). MÉTODOS: O DQOL foi traduzido ao português segundo protocolo e aplicado em 121 indivíduos (56,2% mulheres), com tempo diagnóstico médio de diabetes melito tipo 2 de 8,1 ± 7,13 anos e na faixa etária de 32 a 89 anos. RESULTADOS: O instrumento apresentou consistência interna total (alfa de Cronbach = 0,92). Todas as questões apresentaram correlação positiva (p < 0,01) com seus domínios e com o escore geral do questionário, exceto as questões 18 e 35, que requereram exclusão da versão traduzida. O instrumento foi capaz de diferenciar pacientes com HbA1c acima e abaixo de 9% (p = 0,01). CONCLUSÃO: O DQOL-Brasil apresenta aspectos de confiabilidade e validade adequados para sua utilização em pacientes adultos com diabetes tipo 2.
Internações por pé diabético: comparação entre o custo direto estimado e o desembolso do SUS
Authors: Rezende Karla F. , Nunes Marco A. P. , Melo Naira H. , Malerbi Domingos , Chacra Antônio R. , Ferraz Marco B.
Published: May 2008

Foram seguidas 109 internações de pacientes com diabetes e ulcerações nos pés na rede do Sistema Único de Saúde (SUS) em Sergipe, com o objetivo de estimar o custo direto hospitalar e comparar com os valores do desembolso do SUS. Os dados foram coletados desde a admissão até a alta ou o óbito dos casos incluídos, sendo anotadas as características clínicas dos pacientes e os desfechos das internações. Foram calculados o custo direto estimado e o desembolso do SUS. Todos eram portadores de diabetes tipo 2 e a maioria das ulcerações (64,2%) foram classificadas como Wagner 4 ou 5. Evoluíram com alta sem amputação 43 pacientes (39,4%) e 52 (47,7%) com alta após amputação. Evoluíram para óbito 14 pacientes (12,8%). O custo estimado variou de R$ 943,72 a R$ 16.378,85, com média de R$ 4.461,04. O valor do desembolso do SUS variou de R$ 96,95 a R$ 2.410,18, com média de R$ 633,97, cerca de sete vezes inferior. As menores defasagens entre os custos ocorreram nos pacientes assistidos no Hospital Beneficente e as maiores naqueles tratados com amputações menores.
Hipertireoidismo relacionado à síndrome de McCune Albright: relato de dois casos e revisão da literatura
Authors: Sallum Ana Carolina R. , Leonhardt Fernando D. , Cervantes Onivaldo , Abrahão Márcio , Yazaki Reinaldo K.
Published: May 2008

INTRODUÇÃO: A síndrome de McCune Albright é uma doença rara, clinicamente definida pela combinação de displasia fibrosa poliostótica, manchas café-com-leite e endocrinopatias com hiperfunção, como puberdade precoce, hipertireoidismo, acromegalia e outras. A fisiopatologia biomolecular baseia-se em uma mutação ativadora do gene para a subunidade alfa da proteína de membrana Gs, que estimula a produção intracelular de AMPc, conferindo secreção autônoma à glândula em particular. A glândula tireóide é freqüentemente envolvida nesta doença, sendo o hipertireoidismo a segunda endocrinopatia mais comum após a puberdade precoce. OBJETIVO: Realizar uma revisão da literatura no período de 1937 a 1997, incluindo nossa casuística, e discutir o tratamento utilizado para o hipertireoidismo nesta síndrome. RESULTADOS: Do total de 85 casos, em 26 com hipertireoidismo se descreve o tipo de tratamento utilizado. Entre esses, 15 foram submetidos à cirurgia (tireoidectomia total), seis foram submetidos à iodoterapia e cinco foram submetidos a tratamento com drogas antitireoidianas (DAT - propiltiuracil, carbimazol ou metimazol), pois em alguns houve associação dos tratamentos citados anteriormente. CONCLUSÃO: A síndrome de McCune-Albright é uma doença rara, que inclui displasia fibrosa poliostótica, manchas café-com-leite e endocrinopatias com hiperfunção. Os casos acompanhados com hipertireoidismo são inicialmente tratados clinicamente com DAT, porém a ablação cirúrgica ou com radioiodoterapia é a opção definitiva mais indicada.
Cetoacidose diabética associada com síndrome de Guillain-Barré: relato de caso
Authors: Noviello Thiago Bechara , Noviello Teresa Cristina B. , Purisch Saulo , Lamounier Rodrigo Nunes , Reis Janice Sepúlveda , Menezes Patrícia A. F. da Cunha , Calsolari Maria Regina
Published: May 2008

A síndrome de Guillain-Barré (GBS) é uma desordem causada por exacerbada resposta imune aos processos infecciosos. O diabetes melito (DM) não é reconhecido como uma causa desta polirradiculopatia inflamatória, com poucos casos relatados na literatura sobre tal associação. Apresentamos um caso de uma paciente do sexo feminino, 44 anos, admitida com história recente de poliúria, polidipsia, perda de peso e astenia, glicemia de 562 mg/dL, em cetoacidose, sem foco infeccioso. Posteriormente desenvolveu quadro de polirradiculopatia, insuficiência respiratória e alteração liquórica compondo o quadro de GBS. No presente relato, a paciente recuperou-se plenamente do déficit neurológico, assim como da hiperglicemia, configurando quadro de diabetes tipo 2, com tendência à cetoacidose, evoluindo sem insulino-dependência.