Isolation and characterization of microsatellite loci in Bemisia tabaci

Bemisia tabaci (Hemiptera: Aleyrodidae) is a haplo-diploid species with a global distribution demonstrating strong geographical structure with eight recognizable genetic groups. Fifteen microsatellite loci (335 alleles, 6-44 alleles per locus) were derived from four of the eight groups and were then screened across 33 populations. These loci clearly differentiate the populations. The microsatellites amplified best in individuals from genetic groups representing the Mediterranean, Middle East, Asia (three groups) and Australasia/Oceania and amplified less well with populations from sub-Saharan Africa and the New World. This differential amplification pattern is a direct result of the relatedness to the microsatellite source material.

Testing the link between the latitudinal gradient in species richness and rates of molecular evolution

Numerous hypotheses have been proposed to explain latitudinal gradients in species richness, but all are subject to ongoing debate. Here we examine Rohde's (1978, 1992) hypothesis, which proposes that climatic conditions at low latitudes lead to elevated rates of speciation. This hypothesis predicts that rates of molecular evolution should increase towards lower latitudes, but this prediction has never been tested. We discuss potential links between rates of molecular evolution and latitudinal diversity gradients, and present the first test of latitudinal variation in rates of molecular evolution. Using 45 phylogenetically independent, latitudinally separated pairs of bird species and higher taxa, we compare rates of evolution of two mitochondrial genes and DNA-DNA hybridization distances. We find no support for an effect of latitude on rate of molecular evolution. This result casts doubt on the generality of a key component of Rohde's hypothesis linking climate and speciation.

The coincidence of thrips and dispersed pollen in PNRSV-infected stonefruit orchards - a precondition for thrips-mediated transmission via infected pollen

Recent laboratory studies have demonstrated that Prunus necrotic ringspot virus (PNRSV) (family Bromoviridae) can be readily transmitted when thrips and virus-bearing pollen are placed together on to test plants. For this transmission mechanism to result in stonefruit tree infection in the field, PNRSV-bearing pollen must be deposited onto surfaces of stonefruit trees on which thrips also occur. In a previous paper, we demonstrated that almost all pollen in a PNRSV-infected Japanese plum orchard in southeastern Queensland was deposited onto flowers, whereas few grains occurred on leaves and none on stems. Here, we present results of our investigation of thrips species composition, distribution and abundance on stonefruit trees in the same study area as our previous pollen deposition study. We collected a total of 2010 adult thrips from 13 orchards during the 1989, 1991 and 1992 flowering seasons of which all but 14 were in the suborder Terebrantia. Most (97.4%) terebrantian thrips were of three species, Thrips imaginis, Thrips australis and Thrips tabaci. Thrips tabaci as well as species mixtures that included T imaginis, T australis and T tabaci have been shown to transmit PNRSV via infected pollen in laboratory tests. Adult thrips were frequently collected from flowers but rarely from leaves and never from stems. Large and significant differences in numbers of T imaginis, T australis and T tabaci adults in flowers occurred among orchards and between seasons. No factor was conclusively related to thrips numbers but flowers of late-flowering stonefruit varieties tended to hold more thrips than those of early-flowering varieties. Our results indicate that the common thrips species present on stonefruit trees in the Granite Belt are also ones previously shown to transmit PNRSV via infected pollen in the laboratory and that these thrips are concentrated in stonefruit flowers where most stonefruit pollen is deposited. These results contribute to mounting circumstantial evidence that stonefruit flowers may be inoculated with PNRSV via an interaction of thrips with virus-bearing pollen and that this transmission mechanism may be an important cause of new tree infections in the field.

Genetic structure of a population of Ganoderma boninense on oil palm

Ganoderma boninense (the causal agent of basal stem rot of oil palm in Papua New Guinea) has a tetrapolar mating system with multiple alleles. Investigations into the population structure of G. boninense, using interfertility between isolates as a marker, revealed that the population on oil palm was comprised predominantly of genetically distinct individuals, although a number of isolates were found to share single mating alleles. No direct hereditary relationship was found between isolates on neighbouring or spatially separated diseased palms, indicating that outcrossing had probably occurred over several generations in the founder population prior to colonization of oil palm. In this study, a total of 81 A and 83 B mating type alleles (factors) were detected with 18 allelic repeats at the A locus and 17 at the B locus. Alleles appeared to be randomly dispersed throughout the population in each study block, although there was a significantly (P

Calcium treatment of harvested Geraldton waxflower does not enhance postharvest quality

Postharvest flower abscission from cut Geraldton waxflower (Chamelaucium uncinatum) is mostly caused by fungal invasion. Elevated plant tissue calcium concentrations through postharvest application reduces fungal disease severity in various crops. Such results may be explained by strengthening of plant cell walls by calcium. Strengthening provides a structural barrier to fungal hyphae, thereby restricting invasion of plant cells. Postharvest pulsing with calcium solution substantially increased calcium concentrations in waxflower tissues. Ca-45 tracer revealed calcium distribution throughout flowering sprigs, including infection sites such as stylar tissue. However, pulsing waxflower sprigs with calcium did not suppress either disease or flower abscission, nor did it enhance vase life.

Efficacy, timing and method of application of fungicides for management of sorghum ergot caused by Claviceps africana

Trials conducted in Queensland, Australia between 1997 and 2002 demonstrated that fungicides belonging to the triazole group were the most effective in minimising the severity of infection of sorghum by Claviceps africana, the causal agent of sorghum ergot. Triadimenol ( as Bayfidan 250EC) at 0.125 kg a. i./ha was the most effective fungicide. A combination of the systemic activated resistance compound acibenzolar-S-methyl ( as Bion 50WG) at 0.05 kg a. i./ha and mancozeb ( as Penncozeb 750DF) at 1.5 kg a. i./ha has the potential to provide protection against the pathogen, should triazole-resistant isolates be detected. Timing and method of fungicide application are important. Our results suggest that the triazole fungicides have no systemic activity in sorghum panicles, necessitating the need for multiple applications from first anthesis to the end of flowering, whereas acibenzolar-S-methyl is most effective when applied 4 days before flowering. The flat fan nozzles tested in the trials provided higher levels of protection against C. africana and greater droplet deposition on panicles than the tested hollow cone nozzles. Application of triadimenol by a fixed wing aircraft was as efficacious as application through a tractor-mounted boom spray.

Phytophthora sojae avirulence genes Avr4 and Avr6 are located in a 24kb, recombination-rich region of genomic DNA

A cross between two different races (race 7 x race 25) of the soybean root and stem rot pathogen Phytophthora sojae was analyzed to characterize the genomic region flanking two cosegregating avirulence genes, Anur4 and Anur6. Both genes cosegregated in the ratio of 82:17 (avirulent:virulent) in an F-2 population, suggestive of a single locus controlling both phenotypes. A chromosome walk was commenced from RAPD marker OPE7.1C, 2.0 cM distant from the Anur4/6 locus. Three overlapping cosmids were isolated which included genetic markers that flank the Anur4/6 locus. The chromosome walk spanned a physical distance of 67 kb which represented a genetic map distance of 22.3cM, an average recombination frequency of 3.0kb/cM and 11.7-fold greater than the predicted average recombination frequency of 35.3 kb/cM for the entire P. sojae genome. Six genes (cDNA clones) expressed from the Anur4/6 genomic region encompassed by the cosmid contig were identified. Single nucleotide polymorphisms and restriction fragment length polymorphisms showed these six genes were closely linked to the Anur4/6 locus. Physical mapping of the cDNA clones within the cosmid contig made it possible to deduce the precise linkage order of the cDNAs. None of the six cDNA clones appear to be candidates for Anur4/6. We conclude that two of these cDNA clones flank a physical region of approximately 24 kb and 4.3 cM that appears to include the Anur4/6 locus. (C) 2003 Elsevier Inc. All rights reserved.

Evidence for a QTL on chromosome 19 influencing LDL cholesterol levels in the general population

The genetic basis of cardiovascular disease (CVD) with its complex etiology is still largely elusive. Plasma levels of lipids and apolipoproteins are among the major quantitative risk factors for CVD and are well-established intermediate traits that may be more accessible to genetic dissection than clinical CVD end points. Chromosome 19 harbors multiple genes that have been suggested to play a role in lipid metabolism and previous studies indicated the presence of a quantitative trait locus (QTL) for cholesterol levels in genetic isolates. To establish the relevance of genetic variation at chromosome 19 for plasma levels of lipids and apolipoproteins in the general, out-bred Caucasian population, we performed a linkage study in four independent samples, including adolescent Dutch twins and adult Dutch, Swedish and Australian twins totaling 493 dizygotic twin pairs. The average spacing of short-tandem-repeat markers was 6 - 8 cM. In the three adult twin samples, we found consistent evidence for linkage of chromosome 19 with LDL cholesterol levels ( maximum LOD scores of 4.5, 1.7 and 2.1 in the Dutch, Swedish and Australian sample, respectively); no indication for linkage was observed in the adolescent Dutch twin sample. The QTL effects in the three adult samples were not significantly different and a simultaneous analysis of the samples increased the maximum LOD score to 5.7 at 60 cM pter. Bivariate analyses indicated that the putative LDL-C QTL also contributed to the variance in ApoB levels, consistent with the high genetic correlation between these phenotypes. Our study provides strong evidence for the presence of a QTL on chromosome 19 with a major effect on LDL-C plasma levels in outbred Caucasian populations.

A genetic map of macadamia based on randomly amplified DNA fingerprinting (RAF) markers

The first genetic linkage map of macadamia (Macadamia integrifolia and M. tetraphylla) is presented. The map is based on 56 F-1 progeny of cultivars 'Keauhou' and 'A16'. Eighty-four percent of the 382 markers analysed segregated as Mendelian loci. The two-way pseudo-testcross mapping strategy allowed construction of separate parental cultivar maps. Ninety bridging loci enabled merging of these maps to produce a detailed genetic map of macadamia, 1100 cM in length and spanning 70-80% of the genome. The combined map comprised 24 linkage groups with 265 framework markers: 259 markers from randomly amplified DNA fingerprinting (RAF), five random amplified polymorphic DNA (RAPD), and one sequence-tagged microsatellite site (STMS). The RAF marker system unexpectedly revealed 16 codominant markers, one of them a putative microsatellite locus and exhibiting four distinct alleles in the cross. This molecular study is the most comprehensive examination to date of genetic loci of macadamia, and is a major step towards developing marker-assisted selection for this crop.

In search of the ultimate ionosonde deduced equator

A further progress has been made in defining the ionosonde deduced equator (IDE) which characterises a latitudinal transition from the northern to southern hemisphere. It is now possible to define the global IDE location as the locus of the average position between geographic and geomagnetic equators. A more complete insight to the phenomenon of the third equator (i.e. after geographic and geomagnetic equators) was made possible due to availability of ionospheric height (h'F) data from three stations positioned close to the IDE in the American and the far-east sectors. The IDE ionospheric signature (or E-type signature), detected at these stations, consists of bi-annual h'F height increases. This signature however is not consistently observed during solar cycle and at times, particularly at sunspot minimum, a weak hemispheric signature is observed (i.e. the northern or southern hemisphere signature). In general, the height increase at the IDE are considerably smaller (by a factor of 4) than at other equatorial locations, indicating that the ionosphere at the IDE location becomes less disturbed. It is suggested that the equatorial longitudinal regions which can be associated with more consistent E-type signature are located in the central Pacific and at the east coast of America, close to the intersection points of the geographic and geomagnetic equators. (C) 2003 Elsevier Ltd. All rights reserved.

Genetic characterization of pilin glycosylation and phase variation in Neisseria meningitidis

Pili of Neisseria meningitidis are a key virulence factor, being the major adhesin of this capsulate organism and contributing to specificity for the human host. Pili are post-translationally modified by addition of either an O-linked trisaccharide, Gal (beta1-4) Gal (alpha1-3) 2,4-diacetamido-2,4,6-trideoxyhexose or an O-linked disaccharide Gal (alpha1,3) GlcNAc. The role of these structures in meningococcal pathogenesis has not been resolved. In previous studies we identified two separate genetic loci, pglA and pglBCD, involved in pilin glycosylation. Putative functions have been allocated to these genes; however, there are not enough genes to account for the complete biosynthesis of the described structures, suggesting additional genes remain to be identified. In addition, it is not known why some strains express the trisaccharide structure and some the disaccharide structure. In order to find additional genes involved in the biosynthesis. of these structures, we used the recently published group A strain Z2491 and group B strain MC58 Neisseria meningitidis genomes and the unfinished Neisseria meningitidis group C strain FAM18 and Neisseria gonorrhoeae strain FA1090 genomes to identify novel genes involved in pilin glycosylation, based on homology to known oligosaccharide biosynthetic genes. We identified a new gene involved in pilin glycosylation designated pglE and examined four additional genes pgIB/B2, pglF, pglG and pglH. A strain survey revealed that pglE and pglF were present in each strain examined. The pglG, pglH and pgIB2 polymorphisms were not found in strain C311#3 but were present in a large number of clinical isolates. Insertional mutations were constructed in pglE and pglF in N. meningitidis strain C311#3, a strain with well-defined lipopolysaccharide (LPS) and pilin-linked glycan structures. Increased gel migration of the pilin subunit molecules of pglE and pglF mutants was observed by Western analysis, indicating truncation of the trisaccharide structure. Antisera specific for the C311#3 trisaccharide failed to react with pilin from these pglE and pglF mutants. GC-MS analysis of the sugar composition of the pglE mutant showed a reduction in galactose compared with C311#3 wild type. Analysis of amino acid sequence homologies has suggested specific roles for pglE and pglF in the biosynthesis of the trisaccharide structure. Further, we present evidence that pglE, which contains heptanucleotide repeats, is responsible for the phase variation between trisaccharide and disaccharide structures in strain C311#3 and other strains. We also present evidence that pglG, pglH and pgIB2 are potentially phase variable.

Dimens??es do papel do Conanda na efetiva????o dos direitos humanos de crian??as e adolescentes para conselheiros nacionais: o debate sobre grandes eventos esportivos no Brasil

O contexto pol??tico e social brasileiro, desde as ??ltimas d??cadas do s??culo passado, tem sido marcado pelo processo de redefini????o do papel do Estado, a partir da universaliza????o dos direitos de cidadania, descentraliza????o administrativa e gest??o democr??tica das pol??ticas p??blicas. Trata-se, assim, de um novo formato institucional, legitimado pela Constitui????o Federal de 1988, integrante do processo de implementa????o da gest??o participativa, que ocorreu no Brasil principalmente a partir dos anos 90, nas esferas municipal, estadual e federal. Nesse novo formato institucional, surgem os Conselhos de Pol??ticas P??blicas como um novo padr??o de intera????o entre governo e sociedade, exigindo-se dos cidad??os uma atua????o efetiva, por meio de processos interativos, no ??mbito da gest??o p??blica. Esse modelo de gest??o absorve em sua estrutura v??rios segmentos da sociedade, constituindo o novo locus de articula????o pol??tica na defesa pela democratiza????o da gest??o das pol??ticas p??blicas, atrav??s dos quais sujeitos diversos interagem no processo de delibera????o, implementa????o, monitoramento, avalia????o e controle social das pol??ticas p??blicas, nas diversas tem??ticas e ??reas sociais. Este trabalho pretende analisar a capacidade do principal espa??o interinstitucional da inf??ncia e adolesc??ncia do Brasil de influenciar a agenda governamental e as pol??ticas p??blicas federais: o Conselho Nacional dos Direitos da Crian??a e do Adolescente (criado na d??cada de 1990). Para esta an??lise, a pesquisa foca no papel do Conanda na defesa, promo????o e prote????o dos direitos de crian??as e adolescentes no ??mbito do debate sobre grandes eventos esportivos no Brasil. Esta an??lise revela as possibilidades e limites do Conselho de influenciar na constitui????o da agenda p??blica na tem??tica, na decis??o dos agentes de Estado e na formula????o de pol??ticas, na perspectiva da efetiva????o dos direitos fundamentais constitucionais de crian??as e adolescentes

Processos de aprendizagem e inova????o na legisla????o de compras e contrata????es da administra????o p??blica federal: a cria????o do preg??o

Este trabalho resgata uma experi??ncia de aplica????o de processos de aprendizagem na inova????o da legisla????o de compras da administra????o federal. Analisa de que forma uma adequada e criativa gest??o de compet??ncias tecnol??gicas pode efetivamente mobilizar as entidades p??blicas a aperfei??oar ou mudar seus servi??os e processos. A implanta????o do preg??o, como modalidade inovadora de licita????o, mobilizou esfor??os do ??rg??o respons??vel pela normatiza????o das compras governamentais, que se estenderam a toda a administra????o federal, por meio de h??beis mecanismos de dissemina????o da inova????o. Ainda que bem sucedida, a an??lise do per??odo no qual se desenvolveu esta experi??ncia ??? entre 1999 e 2001 ??? mostra avan??os e limita????es na gest??o de compet??ncias praticada na ??rea de compras e no ??mbito do sistema de ??rg??os e entidades que a comp??e. O trabalho procura sistematizar estes aspectos e sugere recomenda????es no sentido de assegurar a continuidade e amplia????o das in??meras pr??ticas gerenciais bem sucedidas que a pesquisa realizada revelou. Os t??picos que se seguem apresentam a estrutura de conceitos que orienta a an??lise desenvolvida, baseada em estudos recentes que abordam a constru????o e sustenta????o de compet??ncias tecnol??gicas nas organiza????es. Uma breve explana????o sobre a organiza????o sist??mica adotada na ??rea de compras da administra????o federal situa o locus institucional no qual se desenvolveu a inova????o. O desenvolvimento e implanta????o do preg??o s??o detalhadamente descritos, na perspectiva dos processos de aprendizagem que engendrou e da forma como foram gerenciados. Os tipos de processos de aprendizagem s??o identificados de forma sistem??tica e analisados com base em caracter??sticas chave, relacionadas com as dimens??es de gest??o. O trabalho sugere nas suas conclus??es, recomenda????es pr??ticas para a gest??o de compet??ncias visando a inova????o, na ??rea de compras governamentais.

Liberação de nutrientes pela palhada de milheto em diferentes estádios fenológicos

Trabalho apresentado no XXXI Congresso Brasileiro de Ciência do Solo (2007 : Gramado, RS)

O desenho da criança de cinco anos : investigando/refletindo as formas produzidas a partir de imagem da arte

O desenho infantil comprova significados e sentidos estabelecidos historicamente e revela experiências comuns da criança pensar e idealizar o mundo. Diante dessa constatação, o cerne desta pesquisa é investigar e refletir sobre as nuances no desenho da criança de cinco anos quando apresentadas às imagens de arte, analisando e compreendendo como ela se expressa verbal e graficamente diante de informações mediadas pelo professor de arte, quando manifestam suas experiências individuais e/ou em grupo, representando suas vivências e apropriando-se da linguagem artística, e assim constituindo-se como autoras. Para sustentar a pesquisa, adotamos os princípios da pesquisa qualitativa utilizando como recurso a observação participante em sala de aula, que vem ao encontro às nossas propostas por oportunizar o registro de dados in locus, potencializando assim, a estratégia da produção de dados. Os sujeitos dessa pesquisa são vinte e uma crianças de cinco anos que frequentaram o Grupo Cinco, do Centro de Educação Infantil Criarte/Ufes. A pesquisa buscou entender o desenho infantil como expressão intrínseca da criança, que, oportunizado por ações que colaboram para esse fazer, dará significados ao objeto, que, associado a sua história, sua vivência, possivelmente contribuirá para a formação artística e imagética da criança, significando sua expressão e criação. Trazemos para esse estudo conceitos do desenho infantil, bem como questões que abarcam todo o processo de elaboração e maturação do desenho, fundamentados nas pesquisas de Rosa Iavelberg, Analice Pilar, César Cola, Arno Stern e Viktor Lowenfeld, dentre outros, os quais possibilitaram nossa análise a partir do desenho e da fala das crianças. As reflexões apresentadas procuram contribuir para compreendermos o processo de diálogo, envolvimento e representação gráfica das crianças com as imagens de arte.