bluuebunny/crossref_metadata_2025 huggingface dataset:
AnALMT1Gene Cluster Controlling Aluminum Tolerance at theAlt4Locus of Rye (Secale cerealeL.)
Authors: Collins N C , Shirley N J , Saeed M , Pallotta M , Gustafson J P
Published: May 2008

Aluminum toxicity is a major problem in agriculture worldwide. Among the cultivated Triticeae, rye (Secale cereale L.) is one of the most Al tolerant and represents an important potential source of Al tolerance for improvement of wheat. The Alt4 Al-tolerance locus of rye contains a cluster of genes homologous to the single-copy Al-activated malate transporter (TaALMT1) Al-tolerance gene of wheat. Tolerant (M39A-1-6) and intolerant (M77A-1) rye haplotypes contain five and two genes, respectively, of which two (ScALMT1-M39.1 and ScALMT1-M39.2) and one (ScALMT1-M77.1) are highly expressed in the root tip, typically the main site of plant Al tolerance/susceptibility. All three transcripts are upregulated by exposure to Al. High-resolution genetic mapping identified two resistant lines resulting from recombination within the gene cluster. These recombinants exclude all genes flanking the gene cluster as candidates for controlling Alt4 tolerance, including a homolog of the barley HvMATE Al-tolerance gene. In the recombinants, one hybrid gene containing a chimeric open reading frame and the ScALMT1-M39.1 gene each appeared to be sufficient to provide full tolerance. mRNA splice variation was observed for two of the rye ALMT1 genes and in one case, was correlated with a ∼400-bp insertion in an intron.
FER1 and FER2 Encoding Two Ferritin Complexes in Chlamydomonas reinhardtii Chloroplasts Are Regulated by Iron
Authors: Long Joanne C , Sommer Frederik , Allen Michael D , Lu Shu-Fen , Merchant Sabeeha S
Published: May 2008

Two unlinked genes FER1 and FER2 encoding ferritin subunits were identified in the Chlamydomonas genome. An improved FER2 gene model, built on the basis of manual sequencing and incorporation of unplaced reads, indicated 49% identity between the ferritin subunits. Both FER1 and FER2 transcripts are increased in abundance as iron nutrition is decreased but the pattern for each gene is distinct. Using subunit-specific antibodies, we monitored expression at the protein level. In response to low iron, ferritin1 subunits and the ferritin1 complex are increased in parallel to the increase in FER1 mRNA. Nevertheless, the iron content of the ferritin1 complex is decreased. This suggests that increased expression results in increased capacity for iron binding in the chloroplast of iron-limited cells, which supports a role for ferritin1 as an iron buffer. On the other hand, ferritin2 abundance is decreased in iron-deprived cells, indicative of the operation of iron-nutrition-responsive regulation at the translational or post-translational level for FER2. Both ferritin subunits are plastid localized but ferritin1 is quantitatively recovered in soluble extracts of cells while ferritin2 is found in the particulate fraction. Partial purification of the ferritin1 complex indicates that the two ferritins are associated in distinct complexes and do not coassemble. The ratio of ferritin1 to ferritin2 is 70:1 in iron-replete cells, suggestive of a more dominant role of ferritin1 in iron homeostasis. The Volvox genome contains orthologs of each FER gene, indicating that the duplication of FER genes and potential diversification of function occurred prior to the divergence of species in the Volvocales.
Analysis of Chromatin Structure of Genes Silenced by Heterochromatin in Trans
Authors: Nisha Parul , Plank Jennifer L , Csink Amy K
Published: May 2008

While heterochromatic gene silencing in cis is often accompanied by nucleosomal compaction, characteristic histone modifications, and recruitment of heterochromatin proteins, little is known concerning genes silenced by heterochromatin in trans. An insertion of heterochromatic satellite DNA in the euchromatic brown (bw) gene of Drosophila melanogaster results in bwDominant (bwD), which can inactivate loci on the homolog by relocation near the centric heterochromatin (trans-inactivation). Nucleosomal compaction was found to accompany trans-inactivation, but stereotypical heterochromatic histone modifications were mostly absent on silenced reporter genes. HP1 was enriched on trans-inactivated reporter constructs and this enrichment was more pronounced on adult chromatin than on larval chromatin. Interestingly, this HP1 enrichment in trans was unaccompanied by an increase in the 2MeH3K9 mark, which is generally thought to be the docking site for HP1 in heterochromatin. However, a substantial increase in the 2MeH3K9 mark was found on or near the bwD satellite insertion in cis, but did not spread further. These observations suggest that the interaction of HP1 with chromatin in cis is fundamentally different from that in trans. Our molecular data agree well with the differential phenotypic effect on bwD trans-inactivation of various genes known to be involved in histone modification and cis gene silencing.
The Drosophila Gap Gene giant Has an Anterior Segment Identity Function Mediated Through disconnected and teashirt
Authors: Sanders Lisa R , Patel Mukund , Mahaffey James W
Published: May 2008

The C2H2 zinc-finger-containing transcription factors encoded by the disconnected (disco) and teashirt (tsh) genes contribute to the regionalization of the Drosophila embryo by establishing fields in which specific Homeotic complex (Hom-C) proteins can function. In Drosophila embryos, disco and the paralogous disco-related (disco-r) are expressed throughout most of the epidermis of the head segments, but only in small patches in the trunk segments. Conversely, tsh is expressed extensively in the trunk segments, with little or no accumulation in the head segments. Little is known about the regulation of these genes; for example, what limits their expression to these domains? Here, we report the regulatory effects of gap genes on the spatial expression of disco, disco-r, and tsh during Drosophila embryogenesis. The data shed new light on how mutations in giant (gt) affect patterning within the anterior gt domain, demonstrating homeotic function in this domain. However, the homeosis does not occur through altered expression of the Hom-C genes but through changes in the regulation of disco and tsh.
The Effect of Chromosome Geometry on Genetic Diversity
Authors: Marri Pradeep Reddy , Harris Leigh K , Houmiel Kathryn , Slater Steven C , Ochman Howard
Published: May 2008

Although organisms with linear chromosomes must solve the problem of fully replicating their chromosome ends, this chromosome configuration has emerged repeatedly during bacterial evolution and is evident in three divergent bacterial phyla. The benefit usually ascribed to this topology is the ability to boost genetic variation through increased recombination. But because numerous processes can impact linkage disequilibrium, such an effect is difficult to assess by comparing across bacterial taxa that possess different chromosome topologies. To test directly the contribution of chromosome architecture to genetic diversity and recombination, we examined sequence variation in strains of Agrobacterium Biovar 1, which are unique among sequenced bacteria in having both a circular and a linear chromosome. Whereas the allelic diversity among strains is generated principally by mutations, intragenic recombination is higher within genes situated on the circular chromosome. In contrast, recombination between genes is, on average, higher on the linear chromosome, but it occurs at the same rate as that observed between genes mapping to the distal portion of the circular chromosome. Collectively, our findings indicate that chromosome topology does not contribute significantly to either allelic or genotypic diversity and that the evolution of linear chromosomes is not based on a facility to recombine.
On the Evolution and Expression of Chlamydomonas reinhardtii Nucleus-Encoded Transfer RNA Genes
Authors: Cognat Valérie , Deragon Jean-Marc , Vinogradova Elizaveta , Salinas Thalia , Remacle Claire , Maréchal-Drouard Laurence
Published: May 2008

In Chlamydomonas reinhardtii, 259 tRNA genes were identified and classified into 49 tRNA isoaccepting families. By constructing phylogenetic trees, we determined the evolutionary history for each tRNA gene family. The majority of the tRNA sequences are more closely related to their plant counterparts than to animals ones. Northern experiments also permitted us to show that at least one member of each tRNA isoacceptor family is transcribed and correctly processed in vivo. A short stretch of T residues known to be a signal for termination of polymerase III transcription was found downstream of most tRNA genes. It allowed us to propose that the vast majority of the tRNA genes are expressed and to confirm that numerous tRNA genes separated by short spacers are indeed cotranscribed. Interestingly, in silico analyses and hybridization experiments show that the cellular tRNA abundance is correlated with the number of tRNA genes and is adjusted to the codon usage to optimize translation efficiency. Finally, we studied the origin of SINEs, short interspersed elements related to tRNAs, whose presence in Chlamydomonas is exceptional. Phylogenetic analysis strongly suggests that tRNAAsp-related SINEs originate from a prokaryotic-type tRNA either horizontally transferred from a bacterium or originally present in mitochondria or chloroplasts.
Genomewide Analysis of Box C/D and Box H/ACA snoRNAs in Chlamydomonas reinhardtii Reveals an Extensive Organization Into Intronic Gene Clusters
Authors: Chen Chun-Long , Chen Chong-Jian , Vallon Olivier , Huang Zhan-Peng , Zhou Hui , Qu Liang-Hu
Published: May 2008

Chlamydomonas reinhardtii is a unicellular green alga, the lineage of which diverged from that of land plants >1 billion years ago. Using the powerful small nucleolar RNA (snoRNA) mining platform to screen the C. reinhardtii genome, we identified 322 snoRNA genes grouped into 118 families. The 74 box C/D families can potentially guide methylation at 96 sites of ribosomal RNAs (rRNAs) and snRNAs, and the 44 box H/ACA families can potentially guide pseudouridylation at 62 sites. Remarkably, 242 of the snoRNA genes are arranged into 76 clusters, of which 77% consist of homologous genes produced by small local tandem duplications. At least 70 snoRNA gene clusters are found within introns of protein-coding genes. Although not exhaustive, this analysis reveals that C. reinhardtii has the highest number of intronic snoRNA gene clusters among eukaryotes. The prevalence of intronic snoRNA gene clusters in C. reinhardtii is similar to that of rice but in contrast with the one-snoRNA-per-intron organization of vertebrates and fungi and with that of Arabidopsis thaliana in which only a few intronic snoRNA gene clusters were identified. This analysis of C. reinhardtii snoRNA gene organization shows the functional importance of introns in a single-celled organism and provides evolutionary insight into the origin of intron-encoded RNAs in the plant lineage.
A Linkage Map of the Zebra FinchTaeniopygia guttataProvides New Insights Into Avian Genome Evolution
Authors: Stapley J , Birkhead T R , Burke T , Slate J
Published: May 2008

Passeriformes are the largest order of birds and one of the most widely studied groups in evolutionary biology and ecology. Until recently genomic tools in passerines relied on chicken genomic resources. Here we report the construction and analysis of a whole-genome linkage map for the zebra finch (Taeniopygia guttata) using a 354-bird pedigree. The map contains 876 SNPs dispersed across 45 linkage groups and we found only a few instances of interchromosomal rearrangement between the zebra finch and the chicken genomes. Interestingly, there was a greater than expected degree of intrachromosomal rearrangements compared to the chicken, suggesting that gene order is not conserved within avian chromosomes. At 1068 cM the map is approximately only one quarter the length of the chicken linkage map, providing further evidence that the chicken has an unusually high recombination rate. Male and female linkage-map lengths were similar, suggesting no heterochiasmy in the zebra finch. This whole-genome map is the first for any passerine and a valuable tool for the zebra finch genome sequence project and for studies of quantitative trait loci.
Sex and Deleterious Mutations
Authors: Gordo Isabel , Campos Paulo R A
Published: May 2008

The evolutionary advantage of sexual reproduction has been considered as one of the most pressing questions in evolutionary biology. While a pluralistic view of the evolution of sex and recombination has been suggested by some, here we take a simpler view and try to quantify the conditions under which sex can evolve given a set of minimal assumptions. Since real populations are finite and also subject to recurrent deleterious mutations, this minimal model should apply generally to all populations. We show that the maximum advantage of recombination occurs for an intermediate value of the deleterious effect of mutations. Furthermore we show that the conditions under which the biggest advantage of sex is achieved are those that produce the fastest fitness decline in the corresponding asexual population and are therefore the conditions for which Muller's ratchet has the strongest effect. We also show that the selective advantage of a modifier of the recombination rate depends on its strength. The quantification of the range of selective effects that favors recombination then leads us to suggest that, if in stressful environments the effect of deleterious mutations is enhanced, a connection between sex and stress could be expected, as it is found in several species.
Ccr4 Alters Cell Size in Yeast by Modulating the Timing of CLN1 and CLN2 Expression
Authors: Manukyan Arkadi , Zhang Jian , Thippeswamy Uma , Yang Jingye , Zavala Noelle , Mudannayake Malkanthi P , Asmussen Mark , Schneider Colette , Schneider Brandt L
Published: May 2008

Large, multisubunit Ccr4-Not complexes are evolutionarily conserved global regulators of gene expression. Deletion of CCR4 or several components of Ccr4-Not complexes results in abnormally large cells. Since yeast must attain a critical cell size at Start to commit to division, the large size of ccr4Δ cells implies that they may have a size-specific proliferation defect. Overexpression of CLN1, CLN2, CLN3, and SWI4 reduces the size of ccr4Δ cells, suggesting that ccr4Δ cells have a G1-phase cyclin deficiency. In support of this, we find that CLN1 and CLN2 expression and budding are delayed in ccr4Δ cells. Moreover, overexpression of CCR4 advances the timing of CLN1 expression, promotes premature budding, and reduces cell size. Genetic analyses suggest that Ccr4 functions independently of Cln3 and downstream of Bck2. Thus, like cln3Δbck2Δ double deletions, cln3Δccr4Δ cells are also inviable. However, deletion of Whi5, a transcriptional repressor of CLN1 and CLN2, restores viability. We find that Ccr4 negatively regulates the half-life of WHI5 mRNAs, and we conclude that, by modulating the stability of WHI5 mRNAs, Ccr4 influences the size-dependent timing of G1-phase cyclin transcription.
Caenorhabditis elegans num-1Negatively Regulates Endocytic Recycling
Authors: Nilsson Lars , Conradt Barbara , Ruaud Anne-Françoise , Chen Carlos Chih-Hsiung , Hatzold Julia , Bessereau Jean-Louis , Grant Barth D , Tuck Simon
Published: May 2008

Much of the material taken into cells by endocytosis is rapidly returned to the plasma membrane by the endocytic recycling pathway. Although recycling is vital for the correct localization of cell membrane receptors and lipids, the molecular mechanisms that regulate recycling are only partially understood. Here we show that in Caenorhabditis elegans endocytic recycling is inhibited by NUM-1A, the nematode Numb homolog. NUM-1A∷GFP fusion protein is localized to the baso-lateral surfaces of many polarized epithelial cells, including the hypodermis and the intestine. We show that increased NUM-1A levels cause morphological defects in these cells similar to those caused by loss-of-function mutations in rme-1, a positive regulator of recycling in both C. elegans and mammals. We describe the isolation of worms lacking num-1A activity and show that, consistent with a model in which NUM-1A negatively regulates recycling in the intestine, loss of num-1A function bypasses the requirement for RME-1. Genetic epistasis analysis with rab-10, which is required at an early part of the recycling pathway, suggests that loss of num-1A function does not affect the uptake of material by endocytosis but rather inhibits baso-lateral recycling downstream of rab-10.
The Small Ubiquitin-Like Modifier (SUMO) and SUMO-Conjugating System ofChlamydomonas reinhardtii
Authors: Wang Ying , Ladunga Istvan , Miller Amy R , Horken Kempton M , Plucinak Thomas , Weeks Donald P , Bailey Cheryl P
Published: May 2008

The availability of the complete DNA sequence of the Chlamydomonas reinhardtii genome and advanced computational biology tools has allowed elucidation and study of the small ubiquitin-like modifier (SUMO) system in this unicellular photosynthetic alga and model eukaryotic cell system. SUMO is a member of a ubiquitin-like protein superfamily that is covalently attached to target proteins as a post-translational modification to alter the localization, stability, and/or function of the target protein in response to changes in the cellular environment. Three SUMO homologs (CrSUMO96, CrSUMO97, and CrSUMO148) and three novel SUMO-related proteins (CrSUMO-like89A, CrSUMO-like89B, and CrSUMO-like90) were found by diverse gene predictions, hidden Markov models, and database search tools inferring from Homo sapiens, Saccharomyces cerevisiae, and Arabidopsis thaliana SUMOs. Among them, CrSUMO96, which can be recognized by the A. thaliana anti-SUMO1 antibody, was studied in detail. Free CrSUMO96 was purified by immunoprecipitation and identified by mass spectrometry analysis. A SUMO-conjugating enzyme (SCE) (E2, Ubc9) in C. reinhardtii was shown to be functional in an Escherichia coli-based in vivo chimeric SUMOylation system. Antibodies to CrSUMO96 recognized free and conjugated forms of CrSUMO96 in Western blot analysis of whole-cell extracts and nuclear localized SUMOylated proteins with in situ immunofluorescence. Western blot analysis showed a marked increase in SUMO conjugated proteins when the cells were subjected to environmental stresses, such as heat shock and osmotic stress. Related analyses revealed multiple potential ubiquitin genes along with two Rub1 genes and one Ufm1 gene in the C. reinhardtii genome.
View from the Crossroads
Authors: Fuller Paul , Webster David
Published: May 2008

A dialogue, somewhat in the spirit of Samuel Becket’s Waiting for Godot, exploring early Buddhist attitudes to views, especially as in the Magandiya-sutta of the Sutta-nipata (vv.835-847). Is the aim to have right view, or go beyond views; or is right view about not being attached to any view?
A Philological Approach to Buddhism: The Bukkyo Dendo Kyokai Lectures 1994, K.R. Norman
Authors: Crosby Kate
Published: May 2008

A Philological Approach to Buddhism: The Bukkyo Dendo Kyokai Lectures 1994, K.R. Norman, 2nd edn (Lancaster: Pali Text Society, 2006), pp. xx+250, £23. ISBN: 0860134210
Darlegung der Bedeutung (Atthasalini). Der Kom­mentar zur Dhammasangani. Übersetzt von Bhikkhu Nyanaponika. Redaktionell bearbeitet und ediert von Sven Bretfeld und Rainer Knopf
Authors: Kieffer-Pulz Petra
Published: May 2008

Darlegung der Bedeutung (Atthasalini). Der Kom­mentar zur Dhammasangani. Übersetzt von Bhikkhu Nyanaponika. Redaktionell bearbeitet und ediert von Sven Bretfeld und Rainer Knopf (Oxford: Pali Text Society, 2005), pp. xviii+651, £40, ISBN 0 86013-404-0
Colors of the Robe: Religion, Identity and Difference, Ananda Abeysekara
Authors: Wikremeratna Ananda
Published: May 2008

Colors of the Robe: Religion, Identity and Difference, Ananda Abeysekara (South Carolina: University of South Carolina Press, 2002), pp. xvi+271. ISBN 1-57003-467-2 (hb)
Notes on the Chengju guangming jing, ‘Sutra of Achieving the Bright Light Concentration’
Authors: Pu Chengzhong
Published: May 2008

This paper deals with some points about the translator and contents of a Chinese Buddhist scripture, the Chengju guangming jing. It analyses the links between some historical figures and this scripture, scrutinizes passages of the text closely similar to other scriptures, and clears some doubts over the credibility of its translation. In doing so it is hoped that a better understanding of the authenticity of the text in general and a reliable ascription of translatorship of the scripture in particular can be established.
Bhiksuni Samyukta in the Shorter Chinese Samyukta Agama
Authors: Bingenheimer Marcus
Published: May 2008

This is the third article in a series concerning the Shorter Chinese Samyukta Agama, the Bieyi za ahan jing (T.100) (BZA). The articles are part of a larger project that constructs a digital parallel edition of the 364 suttas of the BZA and their various versions. Starting from the fact that we are dealing with text-clusters, i.e. groups of texts, which share relevant narrative elements, the idea behind this edition is to present the texts of each cluster in a convenient and reliable fashion and to improve on previous editions in various ways. The online interface to the database is currently hosted at: http://buddhistinformatics.chibs.edu.tw/BZA/.
Major Trends and Perspective in Studies in the Functional Dimensions of Indian Monastic Buddhism in the Past One Hundred Years
Authors: Prasad Birendra Nath
Published: May 2008

Indian Buddhist monasteries, as institutions in dynamic interactions with other societal institutions, have created a vast functional matrix or were parts thereof. In the past hundred years or so, contours of this matrix have been generally reconstructed with a macro perspective. Now we need to go beyond macro generalizations. We need to analyse individual monasteries in their local and supra-local contexts.
Popular Buddhist Ritual in Contemporary Hong Kong
Authors: Chan Yiu Kwan
Published: May 2008

Shuilu fahui is a Buddhist rite for saving all sentient beings (pudu) with a complex layer of ritual activities incorporating elements of all schools of Chinese Buddhism, such as Tantric mantras, Tian Tai rituals of asking for forgiveness (chanfa), and Pure Land reciting of Amitabha’s name. The ritual can be dated to the Tang Dynasty (c. 670–673 CE) and has been one of the most spectacular and popular rituals in Chinese Buddhism. Shuilu fahui is still performed in China, Hong Kong, Taiwan and Singapore, and continues to be very popular amongst such Chinese communities. This study is an aid to understanding how Chinese Buddhism is practised by monks and nuns in Hong Kong, and how they interact with lay Buddhists through Shuilu fahui. This rite constructs and represents a unified religious world that contains many important and profound religious meanings, and it continuous to ­develop in order to accommodate the various demands of people in Hong Kong.
The Brazilian time and frequency atomic standards program
Authors: Ahmed Mushtaq , Magalhães Daniel V. , Bebeachibuli Aida , Müller Stella T. , Alves Renato F. , Ortega Tiago A. , Weiner John , Bagnato Vanderlei S.
Published: May 2008

Cesium atomic beam clocks have been the workhorse for many demanding applications in science and technology for the past four decades. Tests of the fundamental laws of physics and the search for minute changes in fundamental constants, the synchronization of telecommunication networks, and realization of the satellite-based global positioning system would not be possible without atomic clocks. The adoption of optical cooling and trapping techniques, has produced a major advance in atomic clock precision. Cold-atom fountain and compact cold-atom clocks have also been developed. Measurement precision of a few parts in 10(15) has been demonstrated for a cold-atom fountain clock. We present here an overview of the time and frequency metrology program based on cesium atoms under development at USP São Carlos. This activity consists of construction and characterization of atomic-beam, and several variations of cold-atom clocks. We discuss the basic working principles, construction, evaluation, and important applications of atomic clocks in the Brazilian program.
Sensitive and rapid titrimetric and spectrophotometric methods for the determination of stavudine in pharmaceuticals using bromate-bromide and three dyes
Authors: Basavaiah Kanakapura , Ramakrishna Veeraiah , Somashekar Chikkaswamy , Kumar Urdigere R. Anil
Published: May 2008

Four sensitive and rapid methods for the determination of stavudine (STV) in bulk drug and in dosage forms were developed and optimized. In titrimetry, aqueous solution of STV was treated with a known excess of bromate-bromide in HCl medium followed by estimation of unreacted bromine by iodometric back titration. Spectrophotometric methods involve the addition of a measured excess of bromate-bromide in HCl medium and subsequent estimation of the residual bromine by reacting with a fixed amount of methyl orange, indigocarmine or thymol blue followed by measurement of absorbance at 520 nm (method A), 610 nm (method B) or 550 nm (method C). In all the methods, the amount of bromate reacted corresponds to the amount of STV. Calculations in titrimetry were based on a 1:0.666 (STV:KBrO3) stoichiometry and the method was found to be applicable over 3.5-10 mg range. A linear increase in absorbance with concentration of STV was observed in the spectrophotometric methods, and the Beer's law was obeyed over the concentration ranges 0.125-1.75, 1-10 and 1-9.0 µg mL-1 STV for method A, method B and method C, respectively. The methods when applied to the determination of STV in tablets and capsules were found to give satisfactory results.
Herpetofauna of an Atlantic rainforest area (Morro São João) in Rio de Janeiro State, Brazil
Authors: Almeida-Gomes Mauricio , Vrcibradic Davor , Siqueira Carla C. , Kiefer Mara C. , Klaion Thaís , Almeida-Santos Patrícia , Nascimento Denise , Ariani Cristina V. , Borges-Junior Vitor N.T. , Freitas-Filho Ricardo F. , van Sluys Monique , Rocha Carlos F.D.
Published: May 2008

We studied the herpetofaunal community from the Atlantic forest of Morro São João, in Rio de Janeiro State, Brazil, and present data on species composition, richness, relative abundance and densities. We combined three sampling methods: plot sampling, visual encounter surveys and pit-fall traps. We recorded sixteen species of amphibians and nine of reptiles. The estimated densities (based on results of plot sampling) were 4.5 ind/100 m2 for amphibians and 0.8 ind/100 m² for lizards, and the overall density (amphibians and lizards) was 5.3 ind/100 m². For amphibians, Eleutherodactylus and Scinax were the most speciose genera with three species each, and Eleutherodactylus binotatus was the most abundant species (mean density of 3.0 frogs/100 m²). The reptile community of Morro São João was dominated by species of the families Gekkonidae and Gymnophtalmidae (Lacertilia) and Colubridae (Serpentes). The gymnophtalmid lizard Leposoma scincoides was the most abundant reptile species (mean density of 0.3 ind/100 m²). We compare densities obtained in our study data with those of other studied rainforest sites in various tropical regions of the world.
Effects of acute and chronic physical exercise and stress on different types of memory in rats
Authors: Mello Pâmela Billig , Benetti Fernando , Cammarota Martín , Izquierdo Iván
Published: May 2008

Here we study the effect of acute and chronic physical exercise in a treadmill and of daily stress (because forced exercise involves a degree of stress) during 2 or 8 weeks on different types of memory in male Wistar rats. The memory tests employed were: habituation in an open field, object recognition and spatial learning in the Morris water maze. Daily foot-shock stress enhanced habituation learning after 2 but not after 8 weeks; it hindered both short- (STM) and long-term memory (LTM) of the recognition task at 2 weeks but only STM after 8 weeks and had no effect on spatial learning after either 2 or 8 weeks. Acute but not chronic exercise also enhanced habituation in the open field and hindered STM and LTM in the recognition task. Chronic exercise enhanced one important measure of spatial learning (latency to escape) but not others. Our findings indicate that some care must be taken when interpreting effects of forced exercise on brain parameters since at least part of them may be due to the stress inherent to the training procedure.
The influence of bromazepam on cortical power distribution
Authors: Sampaio Isabel , Puga Fernanda , Veiga Heloisa , Cagy Mauricio , Piedade Roberto , Ribeiro Pedro
Published: May 2008

The EEG has been widely employed in the assessment of electrophysiological changes induced by distinct medications. Its sensibility in detecting alterations produced by a specific substance may be enhanced by methods of quantitative analyses (qEEG). The present study aimed at investigating the modulatory effects of bromazepam on brain dynamics. The effects of bromazepam (3mg) on EEG power distribution were tested in 10 healthy individuals, in a double-blind experiment. The electrophysiological measure was analyzed across experimental conditions, moments, and electrodes, in the delta, theta, alpha and beta frequency bands separately. A significant decrease of relative power was observed in delta and theta (main effect of condition). No interactions were observed. Although the expected anxiolytic EEG profile was not observed (increased beta and decreased alpha activity), this specific result may be related to other factors such as dosage used and the subjects' general physiological state, and not necessarily to the drug itself.
A Holocene pollen record of savanna establishment in coastal Amapá
Authors: Toledo Mauro B. de , Bush Mark B.
Published: May 2008

The main goal of this study was to investigate how climate and human activities may have influenced ecotonal areas of disjoint savannas within Brazilian Amazonia. The fossil pollen and charcoal records of Lake Márcio (Amapá) were used to provide a Holocene palaeoecological history of this region. Detrended correspondence analysis (DCA) was used to enhance the patterns of sample distribution along the sediment core. A marked vegetation change from closed forests with swamp elements to open flooded savanna at c. 5000 yrs BP was evident from the pollen record. Charcoal analysis revealed a pattern of increased accumulation of particles coincident with the establishment of savannas, suggesting higher fire frequency and human impacts near the lake. A 550-year sedimentary hiatus suggests that the lake depended heavily on floodwaters from the Amazon River, and that it became suddenly isolated from it. When sedimentation restarted in the lake, the environment had changed. A combination of factors, such as reduced river flooding, palaeofires and human occupation may have had a tremendous impact on the environment. As there are no other major changes in vegetation, after 4700 yrs BP, it is plausible to assume that the modern mosaic vegetation formed at that time.
Study of wet precipitation and its chemical composition in South of Brazil
Authors: Teixeira Elba C. , Migliavacca Daniela , Pereira Filho Sadi , Machado Andréa C.M. , Dallarosa Juliana B.
Published: May 2008

The purpose of this study is to analyze the chemical composition of wet precipitation in samples collected at three stations in the Candiota region in the Brazilian state of Rio Grande do Sul (RS). Samples were collected in 2004. Variables analyzed in wet precipitation were pH, conductivity, and concentration of Cl-, NO3-, SO4(2-) F-, Na+, Ca2+, Mg2+, K+, NH4+, Cu, Zn, Fe, Mn, Pb, Ni, Cd, Co, and Cr. SO2 and NO2 distribution over the time were also evaluated. Results have showed that pH < 5.6 are found mostly at Candiota airport (85%), followed by Aceguá (72%) and Três Lagoas (65%). Enrichment Factor of the studied ions in wet deposition revealed higher Ca2+ and SO4(2-) enrichment in Três Lagoas. Factor Analysis applied to metals and major ions allowed identifying the major sources. While Cl-, Na+, Mg2+ are of marine origin, SO4(2-), NO3-, NH4+ ,F- come from anthropogenic sources. Except for Fe and Mn originating from the soil dust, the metals studied showed to have anthropogenic influence The average SO2 and NO2 concentration, as well as SO4(2-) and NO3- in wet precipitation in the Candiota region showed higher concentrations during the warmer months.
Gasto energético corporal: conceitos, formas de avaliação e sua relação com a obesidade
Authors: Melo Camila Maria de , Tirapegui Julio , Ribeiro Sandra Maria Lima
Published: May 2008

A obesidade, apesar de intensamente estudada nos últimos anos, ainda apresenta muitas controvérsias, entre elas a sua relação com o gasto energético (GE). O presente estudo representa uma revisão da literatura procurando abordar: as técnicas existentes para avaliação do GE, com suas vantagens e limitações e as relações existentes entre GE e a obesidade. O GE pode ser avaliado por métodos calorimétricos, espectrométricos, ou mesmo por questionários. De acordo com os objetivos e as possibilidades da pesquisa, todas as técnicas apresentam pontos positivos e limitações. Os indivíduos obesos têm sido apontados como "econômicos", do ponto de vista metabólico, ou seja, gastariam menos energia do que os não obesos. Essa economia tem sido investigada a partir de cada componente do GE diário (GED) (GE de repouso, efeito termogênico à alimentação ou GE da atividade física) e os resultados são bastante controversos. Paralelamente às análises do GE em humanos, estudos moleculares têm auxiliado no esclarecimento desse tema tão complexo. Diferentes hormônios, especialmente os secretados pelo adipócito, bem como proteínas específicas em vários tipos de células, têm auxiliado na compreensão do GE corporal. Muitos estudos ainda são necessários, e é importante que se padronizem as técnicas, de maneira que se permita maior reprodutibilidade dos resultados.
Prevalência de deficiência e insuficiência de vitamina D e sua correlação com PTH, marcadores de remodelação óssea e densidade mineral óssea, em pacientes ambulatoriais
Authors: Silva Bárbara C. Carvalho , Camargos Bruno Muzzi , Fujii Julienne Borges , Dias Eduardo Pimentel , Soares Maria Marta Sarquis
Published: May 2008

A deficiência de vitamina D (VD) leva ao raquitismo e à osteomalacia e sua insuficiência, caracterizada pelo hiperparatireoidismo secundário, pode resultar osteoporose. Apesar de amplamente prevalente, a insuficiência de VD ainda é pouco reconhecida e subtratada. Os autores estudaram 180 pacientes atendidos em ambulatório de endocrinologia em Belo Horizonte, que tiveram os níveis de 25(OH)VD mensurados, correlacionando-os com paratormônio (PTH), marcadores de remodelação óssea e densidade mineral óssea. Para caracterização de níveis insuficientes de VD, foram correlacionados os níveis de 25(OH)VD com os de PTH, definindo-se, nesta série, ponto de corte de 25(OH)VD de 32 ng/ml. Foi encontrada correlação inversa e significativa entre 25(OH)VD e PTH e entre 25(OH)VD e C-telopeptídeo. A prevalência de insuficiência de VD na população estudada foi de 42,4%. Conclui-se que a insuficiência de VD tem alta prevalência entre pacientes que freqüentam nossos consultórios, alertando para a importância da sua investigação na prática clínica e na instituição de políticas para sua prevenção.
Prevalência de doenças tireoidianas auto-imunes em pacientes com lúpus eritematoso sistêmico
Authors: Viggiano Daniela P. P. Oliveira , Silva Nilzio Antônio da , Montandon Ana C. O. e Silva , Barbosa Vitalina de Souza
Published: May 2008

INTRODUÇÃO: As doenças tireoidianas auto-imunes têm sido associadas com inúmeras desordens reumatológicas, incluindo o lúpus eritematoso sistêmico (LES). OBJETIVO: Avaliar a prevalência de alterações tireoidianas em pacientes com LES. MÉTODOS: Estudo de coorte transversal comparando prevalência de alterações tireoidianas em 106 pacientes com LES e grupo-controle de 102 pacientes. Os pacientes foram submetidos à avaliação clínica e laboratorial, com dosagens de anticorpos anti-TPO e anti-Tg, TSH, T4 livre e T3. RESULTADOS: Detectou-se aumento de prevalência de hipotireoidismo subclínico (11%) e clínico (13%) no grupo de pacientes com LES, comparados a 7% e 1%, respectivamente, no grupo-controle (p < 0,001). Não houve diferença de prevalência de hipertireoidismo entre os grupos comparados. A positividade de anticorpos antitireoidianos foi maior no grupo de LES (23% versus 19%, p = 0,025). O risco relativo de pacientes com LES apresentarem alterações tireoidianas foi de 1,60. CONCLUSÃO: As alterações tireoidianas são mais freqüentes em pacientes com LES que na população geral.
Capacidade dos biomarcadores inflamatórios em predizer a síndrome metabólica: Inflammation biomarkers capacity in predicting the metabolic syndrome
Authors: Volp Ana Carolina Pinheiro , Alfenas Rita de Cássia G. , Costa Neuza Maria Brunoro , Minim Valéria Paula Rodrigues , Stringueta Paulo César , Bressan Josefina
Published: May 2008

O processo inflamatório é o elo entre a síndrome metabólica e as doenças cardiovasculares. Para medir o grau da inflamação subclínica, vários biomarcadores inflamatórios têm sido propostos. Este trabalho tem como objetivo revisar as recentes pesquisas das associações entre os biomarcadores inflamatórios e a síndrome metabólica, bem como a capacidade daqueles em predizer a síndrome metabólica. Estes biomarcadores incluem as citocinas pró-inflamatórias, citocinas antiinflamatórias, adipocinas, chemocinas, marcadores de inflamação derivados de hepatócitos, marcadores de conseqüência da inflamação e enzimas. Com esta revisão pode-se integrar o novo conhecimento referente às interações possíveis de mediadores inflamatórios com a síndrome metabólica, visto que estes biomarcadores desempenham vários papéis e seguem diversos caminhos metabólicos.
Uma proposta de avaliação integrada de risco do uso de agrotóxicos no estado do Amazonas, Brasil
Authors: Waichman Andréa Viviana
Published: May 2008

Durante os últimos 30 anos, o aumento da população humana no Amazonas introduziu a necessidade de produção adicional de alimentos e levou o governo do estado a desenvolver programas para aumentar e melhorar a produção agrícola. A produção de hortaliças não tradicionais apresentou vários problemas desconhecidos para os agricultores da região, uma vez que estas culturas não são bem adaptadas às condições locais. A suscetibilidade a insetos, fungos e outras pragas, e a competição com vegetação nativa vem forçando os agricultores a usar intensivamente os agrotóxicos. Os agricultores não estavam preparados para o uso adequado desta tecnologia ignorando os riscos dos agrotóxicos para saúde humana e o ambiente. Os agricultores não usam equipamento de proteção individual, porque é caro, desconfortável e inadequado para o clima quente da região. A falta treinamento e o escasso conhecimento sobre os perigos dos agrotóxicos contribuem para a manipulação incorreta durante a preparação, aplicação e disposição das embalagens vazias. Nestas condições, a exposição dos agricultores, suas famílias, consumidores e ambiente é alta. Como um primeiro passo para o entendimento deste problema e a proposição de soluções é proposta a realização de uma avaliação integrada de risco. As três fases do processo, formulação de problema, avaliação da exposição, e caracterização de risco são detalhadas. Programas de educação, treinamento e informação fazem parte das estratégias para a redução do risco do uso de agrotóxicos permitindo o desenvolvimento de uma agricultura ambientalmente sustentável.
Hybotinae (Diptera, Hybotidae) do Parque Nacional do Jaú, Amazonas, Brasil, com descrição de cinco espécies novas de Syneches Walker
Authors: Ale-Rocha Rosaly , Vieira Renata Magalhães
Published: May 2008

A composição de Hybotinae do Parque Nacional do Jaú foi estudada. Dezesseis espécies de Hybotinae são registradas e cinco espécies novas de Syneches Walker são descritas e ilustradas: Syneches hispidus sp. nov., S. jauensis sp. nov., S. longiflagellatus sp. nov., S. rafaeli sp. nov. e S. vidali sp. nov.
Avaliação do desembarque pesqueiro efetuado em Manacapuru, Amazonas, Brasil
Authors: Gonçalves Cristiano , Batista Vandick da Silva
Published: May 2008

A atividade comercial pesqueira na Amazônia Central é predominantemente direcionada para Manaus, porém o perfil das atividades pesqueiras efetuadas nos demais centros também é fundamental para o planejamento do setor. Neste contexto, o presente trabalho visa caracterizar o perfil da produção pesqueira que abastece a cidade de Manacapuru, um dos principais centros urbanos da Amazônia Central. Os desembarques ocorreram a partir de canoas a remo, canoas motorizadas, barcos de pesca e recreios. A média mensal de pescado desembarcado foi de 175,36 ± 39,50 t em 2001 e de 172,13 ± 18,88 t em 2002, não apresentando diferença significativa entre anos (P>0,05). Dos 35 nomes específicos comuns registrados, observa-se que curimatã (Prochilodus nigricans), jaraquis (Semaprochilodus spp.), cubiu (Anodus spp.), mapará (Hypophthalmus spp.), e tambaqui (Colossoma macropomum) foram os itens mais importantes nos dois anos, e piramutaba (Brachyplatystoma vaillantii) em 2002. Sete sub-regiões foram visitadas pela frota pesqueira, destacando-se Baixo-Solimões e o rio Purus.
Populações de aranhas errantes do gênero Ctenus em fragmentos florestais na Amazônia Central
Authors: Mestre Luiz Augusto Macedo , Gasnier Thierry Ray
Published: May 2008

Ctenus é um gênero de aranhas errantes abundante em florestas tropicais da América do Sul e da África e está se tornando um organismo modelo para compreensão da biologia de predadores na fauna de serapilheira. Avaliamos os efeitos da fragmentação florestal sobre quatro espécies de aranhas errantes do gênero Ctenus (C. amphora, C. crulsi, C. manauara e C. villasboasi), baseado nas variações das densidades e nos tamanhos de adultos em fragmentos de tamanhos diferentes, nas bordas destes e nas florestas secundárias próximas. Este estudo foi realizado de fevereiro a julho de 1999, em floresta tropical úmida de terra firme ao norte de Manaus - AM. As áreas incluíram três locais de mata secundária, quatro fragmentos de 1 ha, três de 10 ha, dois de 100 ha e quatro reservas em floresta contínua (maior que 10.000 ha). As aranhas foram capturadas manualmente, mensuradas e contadas em transectos de 250x5 m ou 500x5 m em áreas de platô, no interior e nas bordas dos fragmentos. Houve predomínio significativo de fêmeas em duas espécies (C. amphora- 74% e C. crulsi- 65%); dimorfismo sexual de tamanho em três espécies (C. amphora, C. crulsi e C. manauara) e variação temporal da abundância significativa para as quatro espécies. Estes resultados corroboraram e complementaram tendências de estudos anteriores e permitem uma interpretação mais completa sobre a ecologia destas espécies. Não observamos diferenças de abundância das aranhas entre centro e bordas e entre reservas de diferentes tamanhos. O efeito de borda ou do tamanho do fragmento sobre o tamanho de aranhas Ctenus neste estudo foi bem menor que as variações anteriormente observadas entre habitats diferentes no interior da floresta. Comparações com um estudo posterior a este, mostram que efeito da fragmentação nesta escala sobre estas aranhas diminui com a regeneração da floresta ao redor dos fragmentos, indicando uma rápida resposta do grupo para estas modificações ambientais.
Infecção natural por tripanosomatídeos (Kinetoplastida: Trypanosomatidae) em Lutzomyia umbratilis (Diptera: Psychodidae) em áreas de leishmaniose tegumentar americana no Amazonas, Brasil
Authors: Pinheiro Francimeire Gomes , Luz Sérgio Luís Bessa , Franco Antonia Maria Ramos
Published: May 2008

Durante o período de 2002 a 2003 foram realizadas coletas de flebotomíneos em duas áreas do estado do Amazonas (Base de treinamento militar - BI1 e Tarumã Mirim). Nessas coletas foram capturadas um total de 1.440 fêmeas de Lutzomyia (Nyssomyia) umbratilis. Lu.umbratilis é a principal responsável pela transmissão da Leishmaniose Tegumentar Americana (LTA) ao norte do Rio Amazonas. Do total coletado apenas 15 espécimens (ou 1,04%) apresentaram infecção natural por tripanosomatídeos, sendo 12 na BI1 e 3 em Tarumã-Mirim. Isso representou uma taxa de infecção de 1,66% (12 dos 720 capturados em BI1) e 0,42% (3 dos 720 em Tarumã-Mirim). Estes resultados confirmam as informações prévias por outros autores de reduzidos valores de infecção natural por tripanosomatídeos em flebotomíneos, mesmo em áreas altamente endêmicas para leishmaniose.
Seasonal abundance of the shipworm Neoteredo reynei (Bivalvia, Teredinidae) in mangrove driftwood from a northern Brazilian beach
Authors: S. Filho Carlos , Tagliaro Claudia H. , Beasley Colin R.
Published: May 2008

Shipworms are important decomposers of wood, especially in mangrove forests where productivity is high. However, little emphasis has been given to the activity of shipworms in relation to the export of nutrients from mangroves to adjacent coastal areas. As a first step to obtaining such information, the frequency of colonized mangrove driftwood as well as shipworm density and length were studied by collecting washed up logs during a year at Ajuruteua beach, state of Pará, northern Brazil. A single species, Neoteredo reynei (Bartsch, 1920), was found colonizing driftwood. Although large colonized logs were most common on the beach, shipworm density was higher in small logs, especially during the dry season. In general, however, density was higher during the wet season (January to April) and lowest in July. Overall shipworm mean length was 9.66cm. In large logs, mean length increased between the wet and dry seasons. However, there was no difference in length among log size categories. Mean shipworm length was similar throughout most of the year but tended to be greater in July. Although salinity varied between 10.9 and 40 during the year, no relationship was found between salinity and density or length. The results suggest that shipworm activity in driftwood logs is relatively constant throughout the year. Increased air humidity and rainfall may promote survival during the wet season. Large logs may take longer to colonize and thus have lower densities than small ones which are scarce probably because they are destroyed rapidly by shipworm activity. However, data on the disintegration of logs would be necessary to test this hypothesis. Larger size of shipworms in the dry season may be related to growth after an earlier recruitment period. Shipworms in large logs during the dry season may be better protected from dessication and high temperatures by the insulating properties of the larger volume of wood.
Tolerance to salinities shocks of the invasive mussel Limnoperma fortunei under experimental conditions
Authors: Angonesi Luciana G. , Rosa Natália G. da , Bemvenuti Carlos E.
Published: May 2008

The golden mussel, Limnoperna fortunei (Dunker, 1857), has been found in the estuarine regions of South America, including the Patos Lagoon (Brazil), a huge choked lagoon with an estuarine region that is highly unstable chemically. Limnoperna fortunei space-temporal variability in the lagoon's estuarine region demonstrated the need to evaluate this species' ability to survive under salinity shocks. A set of experiments was conducted under controlled laboratory conditions. Specimens were tested under salinities of 2, 4, 6, 8 and 12 ppt, and were exposed for periods of 24, 48, 72, 96 and 240 hours. The mussel can survive (90%) up to a salinity shock of 2 ppt for periods of at least 10 days. Considering the influence of climatic and stochastic events and the chemical instability of the Patos Lagoon estuarine region, it's unlikely that populations could survive for longer periods (more than a year) in this area.