511 research outputs found
Gorgoniapolynoe caeciliae (Annelida: Phyllodocida) revisited: previously unknown characters and undescribed species from the Equatorial North Atlantic
As poliquetas são o grupo mais diverso e abundante do Phylum Annelida. Depois dos nematodes são os metazoários mais difundidos no ambiente marinho bentónico. Devido à sua diversidade e distribuição alargada, formam associações estreitas com outros invertebrados marinhos. A grande maioria das poliquetas simbiontes são monoxênicas, isto é, apenas têm uma espécie hospedeira. Espécies que são heteroxénicas e que têm mais de uma espécie hospedeira, tendem a estar associados a espécies hospedeiras intimamente relacionadas; isso sugere um alto grau de especificidade quando se trata de poliquetas simbiontes. A maioria das poliquetas simbiontes forma relações comensais, existindo cerca e 490 espécies de poliquetas descritas envolvidas em 1229 relações comensais. Os membros da família Polynoidae representam 48,86% de todas as relações comensais. Trinta por cento dessas relações comensais ocorrem com hospedeiros do Phylum Cnidaria e envolvem 279 espécies de poliquetas.
Poliquetas comensais de profundidade associados a hospedeiros de coral são um grupo pouco estudado. Actualmente, existem 84 espécies de corais de profundidade envolvidos em 115 relações comensais com um total de 53 espécies de poliquetas, que representam cinco famílias. É provável que esse número esteja sub-estimado devido a vários factores: a ideia correntemente aceite de que as espécies de poliquetas apresentam uma distribuição global; a tendência para espécies de poliquetas estreitamente relacionadas com um plano corporal conservado; a natureza delicada das poliquetas, o que significa que as amostras geralmente são danificadas ou incompletas; técnicas de amostragem não seletivas e destrutivas; número limitado de taxonomistas especializados em poliquetas.
A aplicação de técnicas moleculares com análise morfológica detalhada revelou que muitas espécies com distribuição global constituem várias espécies distintas. Frequentemente, quando a análise molecular revela uma divergência, uma análise morfológica secundária detalhada revela diferenças subtis que antes eram ignoradas e podem ser usadas como caracteres diagnosticantes para delimitar espécies. Se não houver diferenciação morfológica mas divergência genética, essas novas espécies serão chamadas de espécies crípticas. Há duas razões comuns para que a divergência genética ocorra sem alterações morfológicas. Ou a espécie utiliza sinais não visuais de acasalamento (químico), e portanto, não há pressão de seleção sobre caracteres morfológicos ou as espécies existem em ambientes que impõem uma seleção estabilizadora na morfologia. Estas explicações não são mutuamente exclusivas. E ambas as razões podem ser aplicadas às poliquetas e explicar o porquê dos limites das espécies poderem não se correlacionar com as algumas das transformações morfológicas.
Neste estudo, a variação morfológica e genética da poliqueta comensal de profundidade Gorgoniapolynoe caeciliae foi estudada. Esta poliqueta é encontrada em associação com os corais da ordem Alcyonacea. A taxonomia desta espécies e as suas estratégias de vida indicam que pode-se tratar de um exemplo de especiação críptica. As amostras foram amostrados em quatro picos submarinos do lado Oeste do Atlântico Equatorial Norte, abrangendo uma distância de quase 3000 quilómetros. Um fragmento do gene mitocondrial citocromo oxidase c sub-unidade I (COI) foi amplificado para 127 amostras. Esses espécimes representam indivíduos de cada local e provenientes de vários hospedeiros (corais da ordem Alcyonacea). Foram igualmente utilizadas sequências de COI provenientes do Genbank de indivíduos do género Gorgoniapolynoe amostrados no sul do Oceano Índico. Realizámos análises de inferência Bayesiana e máxima verosimilhança, bem como testes de delimitação de espécies (AGBD e bPTP). Também foi realizada análise morfológica com caracteres que pudessem ter sido negligenciados anteriormente. Cinco espécimes por localidade foram selecionados para amplificação adicional do gene mitocondrial ribossomal 16S rRNA e dos genes nucleares ribossomais 18S rRNA e 28S rRNA. Estes foram alinhados com sequências de outras espécies de polinóides originárias do GenBank, para inferir a posição filogenética da espécie Gorgoniapolynoe caeciliae na família Polynoidae.
A análise morfológica dividiu as amostras em dois grupos distintos. Os caracteres morfológicos que marcaram os limites desses dois grupos estão de acordo com os caracteres previamente atribuídos por Pettibone (1991) como variação morfológica intraespecífica. Esses caracteres diferenciaram o seguinte: 1) a forma e a distinção do lobo pós-setal neuropodial; 2) a área quitinosa do primeiro élitro modificado; 3) a presença de áreas bulbosas na base dos cirros ventrais. O uso de um microscópio eletrónico de varrimento revelou um novo tipo de notochaeta num dos grupo. Estruturas semelhantes a flagelos, ainda não descobertas, também igualmente observadas emergindo do élitro. Essas estruturas flagelares foram encontradas nos dois grupos e podem ser um caráter definidor do género. A função desses flagelos é ainda desconhecida uma vez que não foram relatados anteriormente em nenhum outro polinóide. É possível que o flagelo seja um órgão sensorial, somatossensorial ou quimiosensorial. A análise histológica revelou a presença de células em forma de copo dentro do élitro, que eram semelhantes às células vistas no élitro de outros polinóides que podem produzir bioluminescência.Gorgoniapolynoe caeciliae (Fauvel 1913) is a deep-sea commensal polychaete that is lives in association with several genera of corals from the order Alcyonacea. The wide geographic range of G. caeciliae, coupled with it having multiple host coral species, and the evolution of its taxonomic description mean that it could potentially be more than one species. This study investigated the morphological and genetic differentiation in G. caeciliae, sampled from four seamounts in the Equatorial North Atlantic. It is the first large scale study to be carried out on the species. Analysis of cytochrome c oxydase subunit I, in tandem with detailed morphological analysis was carried out. Species delimitation models (AGBD and bPTP) inferred that G. caeciliae, as previously described, is in actual fact two distinct species, with a possible third cryptic species which can only be delimited using molecular markers. 16S, 18S and 28S markers were also used infer the species phylogenetic placement within family Polynoidae. Markers from individuals, identified as G. caeciliae, from the South Indian Ocean, were included in the analysis. These may also be a new species, as they are genetically diverged from the Atlantic species. Additionally, scanning electron microscopy revealed the presence of previously undescribed characters; a new type of notochaeta, unique to the redescribed G. caeciliae; and flagellum-like structures that are part of the micropapillae on the elytra. These flagellum-like structures, which were found on all specimens examined with a scanning electron microscopy, are assumed to have a sensory function and may be a new defining character of the genus Gorgoniapolynoe
A role for Tctex-1 (DYNLT1) in controlling primary cilium length
The microtubule motor complex cytoplasmic dynein is known to be involved in multiple processes including endomembrane organization and trafficking, mitosis, and microtubule organization. The majority of studies of cytoplasmic dynein have focussed on the form of the motor that is built around the dynein-1 heavy chain. A second isoform, dynein heavy chain-2, and its specifically associated light intermediate chain, LIC3 (D2LIC), are known to be involved in the formation and function of primary cilia. We have used RNAi in human epithelial cells to define the cytoplasmic dynein subunits that function with dynein heavy chain 2 in primary cilia. We identify the dynein light chain Tctex-1 as a key modulator of cilia length control; depletion of Tctex-1 results in longer cilia as defined by both acetylated tubulin labelling of the axoneme and Rab8a labelling of the cilia membrane. Suppression of dynein heavy chain-2 causes concomitant loss of Tctex-1 and this correlates with an increase in cilia length. Compared to individual depletions, double siRNA depletion of DHC2 and Tctex-1 causes an even greater increase in cilia length. Our data show that Tctex-1 is a key regulator of cilia length and most likely functions as part of dynein-2
ECOPHYSIOLOGICAL ANALYSIS OF YIELD DETERMINATION IN SOYBEAN OF DIFFERENT RELATIVE MATURITIES
Soybean yield differences are a combination of the genotype, environmental conditions, and management practices. Understanding how these factors interact through the analysis of the components involved in yield determination, provides a way to increase potential and actual yields in Kentucky.
Two irrigated experiments were conducted to quantify differences in the mechanisms of yield determination across soybean maturity groups (MG) 2 to 5 (Chapter 1), and to quantify management options (seeding rate and choice of MG cultivar) that increase yield potential of double crop soybean systems (Chapter 2).
Results showed that cultivars used different physiological strategies to achieve high yields, but these were not always consistent across the environments studied. High yields were often associated to a higher efficiency partitioning biomass to seeds that lead to a higher seed number in some cultivars, as well as associated to low seed growth rates (Chapter 1). The choice of MG cultivar had a greater impact on double-crop soybean yields than increasing seeding rates from 40 to 54 seed m-2. The higher seeding rate increased yields by 5% without an interaction with cultivar. Optimal MG choices for double-crop soybean in KY were dependent on the environment
The Munster Plantation, 1583-1641
The subject concerns the settlement of English families in southern Ireland after the death in rebellion of the last earl of Desmond. The survey commission of 1584 reveals the fragmented extent of escheated land and the haphazard nature of confiscation. The decision to colonise from England was not taken until consideration had been made of several alternative schemes. It is shown that the questions of moral legitimacy for the plantation and the general thrust of government policy - much worried over by historians today - did not preoccupy those planning the Munster venture. Brief mention is made over the background of the settlers and their recruitment and grouping. It is shown that a proportion of leading colonists were army men or administrators on the Irish establishment, many of whom with insufficient wealth or influence in England to promote their stipulated settlement. Because of faulty direction and the practical difficulties of such a vast project, assigning land and settling the newcomers took several years. Land claims from local inhabitants further slowed events. The English settlers in the 1590s numbered 3,500 and invested about 20,000 in the plantation. This sum and the small population proved inadequate faced with the rising in 1598. Re-establishment of the plantation in the 17th century was at a much higher level, the English population becoming four times greater in the 1620s than the 1590s, and powerful enough to control a considerable area after the 1641 rebellion. Motives for this increased emigration to Munster are then examined. The traditional reasons - land, new jobs, religious freedom, social advancement, escape from authority - are paraded and found wanting. The final, geographical explanation comes in the last chapter which also establishes the extent to which the English modified Munster and in turn were changed by local conditions. In an appendix are included brief biographical entries of the 35 chief settlers and the fate of their portions up to 1641. <p
Copy number abnormalities in new or progressive 'neurocutaneous melanosis' confirm it to be primary CNS melanoma
Genetic characterization of nodular worm infections in Asian Apes
Parasitic nematodes of Oesophagostomum spp., commonly known, as 'nodular worms' are emerging as the most widely distributed and prevalent zoonotic nematodes. Oesophagostomum infections are well documented in African non-human primates; however, the taxonomy, distribution and transmission of Oesophagostomum in Asian non-human primates are not adequately studied. To better understand which Oesophagostomum species infect Asian non-human primates and determine their phylogeny we analysed 55 faecal samples from 50 orangutan and 5 gibbon individuals from Borneo and Sumatra. Both microscopy and molecular results revealed that semi-wild animals had higher Oesophagostomum infection prevalence than free ranging animals. Based on sequence genotyping analysis targeting the Internal transcribed spacer 2 of rDNA, we report for the first time the presence of O. aculeatum in Sumatran apes. Population genetic analysis shows that there is significant genetic differentiation between Bornean and Sumatran O. aculeatum populations. Our results clearly reveal that O. aculeatum in free-ranging animals have a higher genetic variation than those in semi-wild animals, demonstrating that O. aculeatum is circulating naturally in wildlife and zoonotic transmission is possible. Further studies should be conducted to better understand the epidemiology and dynamics of Oesophagostomum transmission between humans, non-human primates and other wild species and livestock in Southeast Asia
Self-medication by orang-utans (Pongo pygmaeus) using bioactive properties of Dracaena cantleyi
This is the final version of the article. Available from Springer Nature via the DOI in this record.Animals self-medicate using a variety of plant and arthropod secondary metabolites by either ingesting them or anointing them to their fur or skin apparently to repel ectoparasites and treat skin diseases. In this respect, much attention has been focused on primates. Direct evidence for self-medication among the great apes has been limited to Africa. Here we document self-medication in the only Asian great ape, orang-utans (Pongo pygmaeus), and for the first time, to our knowledge, the external application of an anti-inflammatory agent in animals. The use of leaf extracts from Dracaena cantleyi by orang-utan has been observed on several occasions; rubbing a foamy mixture of saliva and leaf onto specific parts of the body. Interestingly, the local indigenous human population also use a poultice of these leaves for the relief of body pains. We present pharmacological analyses of the leaf extracts from this species, showing that they inhibit TNFα-induced inflammatory cytokine production (E-selectin, ICAM-1, VCAM-1 and IL-6). This validates the topical anti-inflammatory properties of this plant and provides a possible function for its use by orang-utans. This is the first evidence for the deliberate external application of substances with demonstrated bioactive potential for self-medication in great apes.We thank our financial supporters: the Wildlife Conservation Society, the U.S. Fish and Wildlife Service Great Apes Conservation Fund, Primate Conservation Inc., Foundation UMI – Saving of Pongidae, the L.S.B. Leakey Foundation, NERC (Natural Environmental Research Council) and the University of Exeter. L.R. and K.D. were supported by the Ministry of Education Youth and Sports, Czech Republic (grant LO1204 from the National Program of Sustainability and Agricultural Research). We are also very grateful to grant No. P505/11/1163 from The Grant Agency of The Czech Republic and to Prof. Jitka Ulrichová for the kind gift of HUVEC cells
Historia del tratamiento metalúrgico del azogue en España
Memoria premiada por la Escuela Especial de Ingenieros de Minas, con arreglo al programa inserto en la Gaceta de 20 de Mayo de 1876, para la adjudicación de premios por cuenta del legado hecho a la citada Escuela por José Gómez PardoCopia digital. Madrid : Instituto San Isidro de Madrid, 200
Is Duct Excision Still Necessary for All Cases of Suspicious Nipple Discharge?
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90572/1/j.1524-4741.2011.01207.x.pd
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