825 research outputs found
Wood consumption and pellet production by Azorean Kalotermitidae: Kalotermes flavicollis and Cryptotermes brevis
Existem nos Açores duas espécies de térmitas da família Kalotermitidae: a Kalotermes flavicollis é uma térmita de madeira verde e é uma praga urbana menor. A Cryptotermes brevis é uma térmita de madeira seca e é uma importante praga para mobiliário e estruturas. São analisadas as espécies de madeira consumidas por cada espécie nos Açores sendo descritas diferenças na cor, tamanho, forma, e modo de despejo das partículas fecais. A taxa de consumo de madeira e a produção de partículas fecais para a espécie Cryptotermes brevis foram estudadas em 49 tipos diferentes de madeiras. Verificou-se que duas espécies de madeira produzidas localmente e muito usadas na construção, Cryptomeria japonica e Eucalyptus sp., foram das mais consumidas, indicando a importância do desenvolvimento de um sistema local para tratamento por pressão em autoclave das madeiras. Entre as madeiras menos consumidas (mais resistentes) encontram-se espécies tropicais, como o Jatobá e a Maçaranduba. As partículas fecais que são expulsas das galerias pelas térmitas são a forma mais conspícua de detectar infestações por Cryptotermes brevis, dando bons meios para monitorizar a localização de térmitas, o tamanho da colónia e a sua actividade. Foi verificado que a expulsão de partículas fecais é descontínua. Contudo, alguns períodos de expulsão de partículas fecais são contínuos por alguns dias, com taxas de expulsões de 274 partículas fecais, por hora, com acumulações de até 7,8 gramas num período de duas semanas.ABSTRACT: Two termite species of the family Kalotermitidae occur in the Azores: Kalotermes flavicollis is a dampwood termite and minor house pest. Cryptotermes brevis is a dry wood termite and a major pest of furniture and structures. Records of wood species consumed by each species in the Azores are reviewed. Differences in the color, size, shape, disposal of fecal pellets of each species are described. Rates of wood consumption, pellet production were experimentally studied for Cryptotermes brevis on 49 different wood species. Two wood species that are locally produced and widely utilized for construction, Cryptomeria japonica and Eucalyptus sp., were found to be among the most preferred woods for termite consumption indicating an important need for the development of an effective local pressure treatment system for preserving these woods. Least preferred (most resistant woods) included tropical hardwood species such as Jatobá and Maçaranduba. Fecal pellets expelled from galleries by termites are the most conspicuous evidence of Cryptotermes brevis infestations and provide a potential means of monitoring termite location, colony size and activity. Pellet expulsion was found to be discontinuous. However some bouts of pellet dumping were observed to be continuous for at least several days with rates of pellet expulsion of up to 274 pellets per hour, with pellet accumulations of as much as 7.8 grams over a two-week period
Treatment of Cryptotermes brevis infestations in furniture with heat, solid fumigants and inert gases
A Cryptotermes brevis é uma térmita extraordinária na sua capacidade única de atacar madeira extremamente seca. É, igualmente, extraordinária na capacidade de atacar uma grande variedade de tipos de madeira, o que nos leva a concluir como sendo a única espécie de térmitas que é facilmente encontrada em mobílias. Como tal, é muito fácil a sua dispersão aquando do transporte de mobílias infestadas, de lugar para lugar, e esta é uma das principais razões pela qual esta térmita consegue ter uma distribuição tão ampla em áreas urbanas, em praticamente todo mundo. É muito provável que a sua introdução nos Açores tenha sido através de mobília infestada e que a dispersão contínua que se tem verificado de cidade para cidade seja devido a essa razão. Ou seja, o tratamento de mobílias é uma componente importante de um programa integrado para lidar com o controlo e contenção desta espécie de térmita. O objectivo deste trabalho é apresentar os resultados obtidos de três tipos de experiências para tratamento de mobílias infestadas com a Cryptotermis brevis. A primeira experiência consistiu num método muito simples, envolvendo o selar de um objecto infestado dentro de um saco de plástico preto, sendo este colocado num local fora do laboratório, a fim de se encontrar em plena exposição solar durante o mês de Agosto. O método seguinte consistiu em selar um objecto infestado num recipiente com um de três tipos de fumigantes sólidos: bolas de naftalina, para-dichlorobenzeno ou dichlorvos (Vapona®). O último método envolveu um teste de anóxia, em que um de três tipos de gases inertes, azoto (N2), dióxido de carbono (CO2) ou árgon (Ar), foi usado para substituir o ar existente dentro de um saco plástico (bolha) selado, contendo um objecto infestado.ABSTRACT: Cryptotermis brevis is an extraordinary termite in its unique ability to attack extremely dry wood. It is also unique in its ability to attack a wide variety of wood species. This leads to it being one of the only termites in the world which is commonly found attacking furniture. As such, it is easily moved when people move their furniture from place to place and this is one of the reasons why this termite has become widely dispersed to urban areas around the world. It is very likely it was first introduced into the Azores with furniture and that its continued dispersal from island to island and town to town will be by the further movement of infested furniture. Therefore furniture treatment is an important component of an integrated program for dealing with the control and containment of this pest species. The objective of this presentation is to explain the results of three types of experimental furniture treatment that we conducted. The first of these was a simple method involving the sealing of an infested item inside a black plastic bag which was then placed in full sun exposure outdoors during the month of August. The next method involved sealing an infested item in a container with one of three solid fumigants: naphthalene (moth balls), para-dichlorobenzene (PDB moth balls), or dichlorvos (Vapona®). The final method involved anoxia test in which one of three inert gases, either nitrogen (N2), carbon dioxide (CO2), or argon (Air) gases were used to displace the air in a sealed bag holding an infested item
Flight and colony foundation of Azorean termites with emphasis on Cryptotermes brevis
Cada uma das três espécies de térmitas existentes no arquipélago açoriano apresenta um comportamento de voo em momentos distintos ao longo do dia e ao longo do ano. A Cryptotermes brevis tem o seu período de dispersão (de voo) entre os meses de Junho e Agosto no crepúsculo vespertino, a Kalotermes flavicollis de Setembro a Outubro, durante a tarde, e a Reticulitermes grassei tem o seu período de enxameamento na Primavera, durante a manhã. Das espécies referidas, a que apresenta maior importância, por constituir uma praga de dimensões consideráveis em algumas das ilhas, é a C. brevis, a única que tem um comportamento de voo nocturno, tornando, assim, possível o uso de armadilhas luminosas. As experiências aqui apresentadas contêm vários testes com diferentes tipos de luzes, fluorescentes e incandescentes, diferentes cores de armadilhas pegajosas, bem como diferentes tipos de colas e fitas colantes. Após o período de voo, as térmitas exibem uma sequência de comportamentos que foram observados e analisados. Foi estudado o tempo para cada um dos seguintes padrões de comportamento: libertação das asas, comportamento de procura (de um parceiro), formação de pares, selagem da câmara de reprodução (ou ninho), amputação das antenas, início da deposição de ovos e tempo até à primeira eclosão. A preferência por buracos de diferentes diâmetros e diferentes espécies de madeira foi também estudada, assim como a produção de ovos e as taxas de sobrevivência e de produção dos mesmos.ABSTRACT: Each of the three Azorean termite species flies during a different season and different time of the day. Cryptotermes brevis flies from June to August, at dusk; Kalotermes flavicollis flies from September to October, in the afternoon; and Reticulitermes grassei flies during the spring, probably during the morning hours. C. brevis is the most important pest and the only one that flies at night, therefore light trapping is possible. Experiments were conducted with fluorescent and incandescent lights, different colours of sticky traps and different kinds of glue or tape. Following the dispersal flight, the termite exhibits a sequence of behaviours which were observed and analysed. The timing of the follow behavioural events was studied: de-alation, searching behaviour, tandem running, sealing the copulation, de-antennation, commencement of oviposition and time to first hatch. Hole size and wood species preferences for colony establishment were also investigated. In addition, egg production and colony survival rates on different woods were studied
Introdução da térmita da madeira seca Cryptotermes brevis (Walker) nos Açores
A secção Biologia é coordenada pelo Professor Universitário Armindo Rodrigues.A térmita de madeira seca Cryptotermes brevis (Walker) é uma praga urbana que causa danos graves a estruturas de madeira, afectando todos os tipos de equipamentos desde os rodapés, portas, mobiliário e partes estruturais da habitação. Existente principalmente nas zonas tropicais e subtropicais do globo, esta espécie é originaria do Chile e do Peru e poderá ter-se dispersado pelo mundo, numa fase inicial, através do tráfego elevado de navios de madeira espanhóis provenientes dessa zona no século XVI. Esta térmita passa a maior parte do seu ciclo de vida dentro da madeira, factor que facilita o seu transporte e dispersão, uma vez que a sua detecção é difícil por não especialistas.
A sua presença nos Açores é conhecida desde o ano de 2000, altura em que foi identificada a sua presença na Ilha Terceira. Desde então a sua presença já foi confirmada para seis das nove ilhas do arquipélago dos Açores, nomeadamente Terceira, São Miguel, Santa Maria, Faial, São Jorge e Pico.
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Phylogeny, biogeography and ecology of azorean termites
Three species of termites are currently known in the archipelago (the European dampwood termite, Kalotermes flavicollis, the West Indies drywood termite, Cryptotermes brevis, and the Iberian subterranean termite Reticulitermes grassei). All these three species are "lower termites", that is, primitive species having simple galleries but not well formed nests, tending to be less socially advanced and to occur in more temperate latitudes, generally eating only wood but not other types of cellulose, and all having flagellates in the gut. Kalotermes flavicollis is native to most of the Mediterranean region and was probably introduced in the islands many decades ago through vineyard or orchard stocks. In Terceira Island, K. flavicollis is common in the heartwood of several trees and shrubs along the coast. Its colony members may exceed 1000 but the average colony has 600. This termite has been considered as a minor structural pest in a few houses, but structural infestations by this species only occur in association with moisture due to leaks or condensation. Cryptotermes brevis is the most destructive drywood termite pest in the world. Due to its exceptional ability to withstand wood with low moisture content it is able to attack all kinds of dead and dry wood with a strong preference for sapwood over heartwood. It attacks wood in service including structural timbers, beams, studs, rafters, cladding, flooring, molding, doors, window frames and wooden articles such as carvings, tools, picture frames, musical instruments, looms, bed posts, and almost all forms of wood. Serious infestations of this termite are currently known in São Miguel, Terceira, Faial and Santa Maria Islands. Local research has shown that colony size may range up to about 300 but that average colony size is only 45 individuals. Severe damage results not from individual colonies but from high levels of reinfestation leading to the establishment of large numbers of colonies. Successful colony foundation by this termite is promoted by the widespread occurrence of several anobiid beetles whose exit holes in wood provide ideal entrance holes for termite alates. Reticulitermes grassei, a subterranean termite, has only been found in the Azores Archipelago, in the Horta city (Faial Island) where it has been causing severe damage to a few buildings. Reticulitermes colonies may grow to millions of individuals promoted by numerous nymphoid reproductive’s which develop within colonies. Unlike the other two species, colonies of Reticulitermes may spread by tunnelling through the ground
Transcriptomic analysis of plasmid and plasmid-related chromosomal ORFs in C. trachomatis strains with different cell-appetence
Despite the undergoing chromosomal size-reduction of Chlamydia trachomatis, almost all strains maintain the conserved 7,5kb plasmid. It has been recently considered a virulence factor, as plasmid-bearing strains evidenced a higher ability to successfully colonize epithelial cells and sustain infection than plasmidless strains. However, the biological role of the eight plasmid ORFs remains poorly characterized. Thus, we aim to correlate the relative expression of each plasmid ORFs with the number of plasmids per genome as well as with the relative expression of chromosomal genes that seem to be regulated by the plasmid, during the whole Chlamydia developmental cycle.
Both the transcriptomic analysis of all the selected ORFs and the determination of the plasmid copy number were performed by qPCR in prototype and currently circulating strains with distinct cell-appetence and ecological success, throughout Chlamydia developmental cycle.
So far, our results indicate: 1) huge differences (up to 100-fold) in the expression levels between plasmid ORFs; 2) for the same ORF, different expression levels and profiles among strains; 3) variation in the number of plasmids per genome during the infectious cycle; 4) the higher expression level of the plasmid ORFs do not seem to correlate with a higher number of plasmids per genome.
These results, together with our ongoing transcriptomic survey of the plasmid-related chromosomal genes, will contribute to shed some light on the molecular function of the plasmid ORFs in chlamydial biology
Molecular features underlying the higher ecological success of C. trachomatis E and F genotypes
In the light of the >98% genomic similarity among Chlamydia trachomatis serovars, the higher worldwide ecological success of E and F is enigmatic. We intend to provide a quick overview of the molecular data that distinguish these from the remaining strains. Examples are:
- E and F possess a similar chromosomal genetic make-up distinct from the remaining genotypes. Some loci linked to this independent co-segregation comprehend membrane proteins, hypothetical virulence factors, and regulatory regions (published data).
- Some loci reveal nonrandom mutational patterns, where mutations exclusive of E and F are clustered in specific protein domains, likely promoting strains functional and/or structural attributes (published data).
- Based on data from a worldwide survey, MOMP of E and F exhibit the lowest mutation rate (22.3-fold lower), implying more fitted antigenic profiles to deal with host immunity (published data).
- The likelihood of E and F strains to undergo genetic recombination is about 12-fold lower than that of the other genotypes (P<10-2), suggesting a putative clonal evolution, where superimposed favorable clones may be strongly maintained in vivo (preliminary data from our lab).
- Strains E and F do not seem to originate higher infectious load in vivo, when compared with other genital genotypes (published data).
Full-genomic data from multiple and diverse clinical isolates will be essential to decipher the secret behind the higher ecological success of E and F strains
Response of different types of wood treatment regarding the different products application to the management of drywood termites Cryptotermes brevis populations in the Azores
A térmita de madeira seca das Índias Ocidentais, a Cryptotermes brevis (Walker, 1953) (Isoptera: Kalotermitidae) está perfeitamente estabelecida nos Açores, sendo considerada uma praga urbana com grande impacto económico e social pelos graves prejuízos que causa, através da destruição estrutural, principalmente das madeiras de suporte dos telhados. Espera-se com esta contribuição: i) determinar qual o produto com a maior taxa de absorção em todas as madeiras usadas na estrutura dos telhados açorianos; ii) contribuir de uma forma decisiva para que as empresas dos Açores possam adoptar esta prática no tratamento de todas as madeiras a usar nas estruturas; iii) contribuir, indirectamente, para a redução do ataque das térmitas nas madeiras, através do seu tratamento com estes produtos, tendo em vista o controlo desta praga nas zonas urbanas afectadas. De todos os seis produtos utilizados, o XT-2000 (d-limonene), líquido com propriedades insecticidas extraído da casca de citrinos, foi o que melhor foi absorvido e se difundiu no interior da madeira tratada em todas as modalidades ensaiadas. Analisando esta capacidade de difusão no interior da madeira por cada tipo de produto e atendendo ao facto de se tratar de madeira do cerne ou do borne (superfície), o XT-2000 (d-limonene) e o TERMINATE (cialotrina) foram os que registaram a maior percentagem de absorção. Na madeira do cerne, o WOCOSEN (permetrina) foi o que melhor foi absorvido por todas as madeiras. É de referir que a acácia, o sapé e o eucalipto foram as madeiras que registaram a menor taxa de absorção após a aplicação dos produtos ensaiados.ABSTRACT: The West Indian drywood termite, Cryptotermes brevis (Walker, 1953) (Isoptera: Kalotermitidae), is a well-established and serious pest of structural wood in the Azores. It is therefore important to study different ways to fight against this insect, and among the several research studies in progress, in these contribution we discuss the rate of diffusion of six products inside five different kinds of wood that are normally used for construction of Azorean building roofs. Our aims are: i) to test which product is best absorbed in each type of wood tested and used in the building of Azorean roofs; ii) to contribute with methods that can be adopted by Azorean commercial enterprises to develop a domestic termite control industry; iii) to contribute indirectly in understanding the best woods and products we expect to enhance control of these pest in the affected urban areas. Of the six products tested, XT-2000 (d-limonene), a liquid extracted from citrus peels, gave the best results in terms of diffusion on all the wood types tested. When we compared the performance of each kind of product tested in both heartwood and sapwood, XT-2000 and TERMINATE were the products with the greatest amount absorbed in the woods tested. In the heartwood alone, WOCOSEN (permethrin) was the one that gave the best results for all woods. It is also important to note that acácia, sapé and Eucalyptus sp. were the woods that absorbed the least with all the products tested
In silico scrutiny of genes revealing phylogenetic congruence with clinical prevalence or tropism properties of Chlamydia trachomatis strains
Microbes possess a multiplicity of virulence factors that confer them the ability to specifically
infect distinct biological niches. Contrary to what is known for other bacteria, for the obligate intracellular
human pathogen Chlamydia trachomatis, the knowledge of the molecular basis underlying serovars’ tissue
specificity is scarce. We examined all ~900 genes to evaluate the association between individual phylogenies
and cell-appetence or ecological success of C. trachomatis strains. Only ~1% of the genes presented a tree
topology showing the segregation of all three disease groups (ocular, urogenital, and lymphatic) into three wellsupported
clades. Approximately 28% of the genes, which include the majority of the genes encoding putative
type III secretion system effectors and Inc proteins, present a phylogenetic tree where only lymphogranuloma
venereum strains form a clade. Similarly, an exclusive phylogenetic segregation of the most prevalent genital
serovars was observed for 61 proteins. Curiously, these serovars are phylogenetically cosegregated with the
lymphogranuloma venereum serovars for ~20% of the genes. Some clade-specific pseudogenes were identified
(novel findings include the conserved hypothetical protein CT037 and the predicted a-hemolysin CT473),
suggesting their putative expendability for the infection of particular niches. Approximately 3.5% of the genes
revealed a significant overrepresentation of nonsynonymous mutations, and the majority encode proteins that
directly interact with the host. Overall, this in silico scrutiny of genes whose phylogeny is congruent with clinical
prevalence or tissue specificity of C. trachomatis strains may constitute an important database of putative targets
for future functional studies to evaluate their biological role in chlamydial infections.This work was supported by a grant, ERA-PTG/0004/2010, from
Fundação para a Ciência e a Tecnologia (FCT) (to J.P.G.), in the frame
of ERA-NET PathoGenoMics. A.N. is recipient of a FCT post-doctoral
fellowship (SFRH/BPD/75295/2010), V.B. and R.F. are recipients of
Ph.D. fellowships (SFRH/BD/68527/2010 and SFRH/BD/68532/2010,
respectively) from FCT, and V.D. is a recipient of fellowship on behalf
of the grant ERA-PTG/0004/2010
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