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21.
Jens van Wijngaarden Thomas J.A. Snoeks Ermond van Beek Eric L. Kaijzel Clemens W.G.M. Löwik 《Biochemical and biophysical research communications》2010,391(2):1161-1165
In anti-cancer therapy, current investigations explore the possibility of two different strategies to target tumor vasculature; one aims at interfering with angiogenesis, the process involving the outgrowth of new blood vessels from pre-existing vessels, while the other directs at affecting the already established tumor vasculature. However, the majority of in vitro model systems currently available examine the process of angiogenesis, while the current focus in anti-vascular therapies moves towards exploring the benefit of targeting established vasculature as well. This urges the need for in vitro systems that are able to differentiate between the effects of compounds on angiogenesis as well as on established vasculature. To achieve this, we developed an in vitro model in which effects of compounds on different vascular targets can be studied specifically. Using this model, we examined the actions of the fumagillin derivate TNP-470, the MMP-inhibitor marimastat and the recently developed tubulin-binding agent Ang-510. We show that TNP-470 and marimastat solely inhibited angiogenesis, whereas Ang-510 potently inhibited angiogenesis and caused massive disruption of newly established vasculature. We show that the use of this in vitro model allows for specific and efficient screening of the effects of compounds on different vascular targets, which may facilitate the identification of agents with potential clinical benefit. The indicated differences in the mode of action between marimastat, TNP-470 and Ang-510 to target vasculature are illustrative for this approach. 相似文献
22.
Tchalondawa Kisekelwa Jos Snoeks Armel Ibala Zamba Gaston Sefu Amzati Mwapu Isumbisho Pascal Mulungula Masilya Pieter Lemmens Emmanuel Vreven 《Journal of fish biology》2021,99(2):321-334
The African cyprinid genus Labeobarbus is characterized by a high polymorphism in mouth morphology. The association between four species of this genus (two chiselmouths, one rubberlip with a well-developed fleshy mental lobe on the lower jaw, i.e., a fleshy appendage on the chin, and one usually with a poorly developed one) and 26 environmental variables was investigated in four affluents of the Luhoho River in the Albertine Highlands of the Upper Congo basin. A combination of univariate and multivariate analyses suggested that differences exist in habitat composition at localities where different Labeobarbus species were reported, and within different mouth phenotypes. The association of L. longidorsalis with the presence of cobbles and pebbles and of L. brauni with the presence of boulders suggests that the occurrence of chiselmouths phenotype is associated with stony habitats, whereas phenotypes with a mental lobe, i.e., Labeobarbus longifilis and L. paucisquamatus, mostly occupy habitats without stones. Differences in the distribution between these two species appear to be linked to physico-chemical parameters such as electrical conductivity and water temperature rather than substrate type. The findings of this study are relevant for developing guidelines that aim effective local preservation and conservation of these Labeobarbus species. 相似文献
23.
Dieter Anseeuw Gregory E. Maes Paul Busselen Dries Knapen Jos Snoeks Erik Verheyen 《Hydrobiologia》2008,606(1):69-79
Marine protected areas are generally designed and managed on the basis of the presence and extent of specific habitat types
or the habitats of important species. However, it has become clear that in addition to including these ‘structural’ elements
of marine systems, management strategies should incorporate a consideration of the functional aspects of the ecosystems. Biological
traits analysis (BTA) has been successfully used to describe ecological functioning in marine benthic systems. BTA uses a
number of biological characteristics expressed by the taxa present as indicators of key ecosystem functions. Two expert workshops
were used to examine the potential for the application of BTA in the designation and management of MPAs. They concluded that
BTA represented the best tool currently available for quantifying ecological functioning and agreed on 10-key ecological functions
delivered by marine benthic communities. Twenty-four biological traits were also identified by the workshops as indices of
these ten functions. In order to demonstrate the practical utility of the approach, BTA using these traits, was applied to
a dataset covering benthos from within and around the proposed Eddystone Special Area of Conservation (SW England). The case
study demonstrated that with the type of data normally available from conservation assessment type surveys, and a knowledge
of the relevant biological traits, it is possible to use a consideration of ecological functioning to set boundaries for the
MPA and to inform the site management objectives. The use of structure and function information to inform the designation
process and subsequent management of marine protected areas is discussed.
Guest editors: J. Davenport, G. Burnell, T. Cross, M. Emmerson, R. McAllen, R. Ramsay & E. Rogan
Challenges to Marine Ecosystems 相似文献
24.
Gontran Sonet Jos Snoeks Zoltn T. Nagy Emmanuel Vreven Gert Boden Floris C. Breman Eva Decru Mark Hanssens Armel Ibala Zamba Kurt Jordaens Victor Mamonekene Tobias Musschoot Jeroen Van Houdt Maarten Van Steenberge Soleil Lunkayilakio Wamuini Erik Verheyen 《Molecular ecology resources》2019,19(3):728-743
25.
An α‐taxonomic revision of the African pike, Hepsetus odoe, from Lower Guinea is provided. The results show that three different species occur in Lower Guinea instead of one. Hepsetus akawo, recently described from West Africa, is present in the northern part of Lower Guinea; Hepsetus lineata, the most widespread species within Lower Guinea, is known from the Sanaga (Cameroon) in the north to the Shiloango (Democratic Republic of the Congo) in the south and Hepsetus kingsleyae sp. nov. is endemic to the Ogowe Basin. The new species H. kingsleyae is described and H. lineata, which is elevated here to the species level, is redescribed. Hepsetus lineata can easily be recognized by its prominent horizontal line pattern on the flanks and differs further from H. akawo and H. kingsleyae in the number of lateral‐line scales and the number of gill rakers. Hepsetus kingsleyae differs from H. lineata and H. akawo by its narrow head, elongated snout and narrow, knife‐shaped body. All three species are also distinguishable from H. odoe and the recently revalidated H. cuvieri. A few exceptional specimens could not be allocated to one of the three species and may represent hybrids because of their mixed diagnostic characters or their intermediate values. 相似文献
26.
Maarten Van Steenberge Pascal István Hablützel Maarten Pieterjan Maria Vanhove Jos Snoeks 《Frontiers in zoology》2018,15(1):42
Background
Species delineation is particularly challenging in taxa with substantial intra-specific variation. In systematic studies of fishes, meristics and linear measurements that describe shape are often used to delineate species. Yet, little is known about the taxonomic value of these two types of morphological characteristics. Here, we used Tropheus (Teleostei, Cichlidae) from the southern subbasin of Lake Tanganyika to test which of these types of characters best matched genetic lineages that could represent species in this group of stenotypic rock-dwelling cichlids. We further investigated intra-population variation in morphology. By linking this to a proxy of a population’s age, we could assess the evolutionary stability of different kinds of morphological markers.Results
Morphological data was collected from 570 specimens originating from 86 localities. An AFLP approach revealed the presence of five lineages in the southern subbasin: T. moorii, T. brichardi, T. sp. ‘maculatus’, T. sp. ‘Mpimbwe’ and T. sp. ‘red’, which we consider to represent distinct species. Although both types of morphological data supported this classification, a comparison of PST-values that describe inter-population morphological differentiation, revealed a better correspondence between the taxon delineation based on AFLP data and the patterns revealed by an analysis of meristics than between the AFLP-based taxon delineation and the patterns revealed by an analysis of shape. However, classifying southern populations of Tropheus was inherently difficult as they contained a large amount of clinal variation, both in genetic and in morphological data, and both within and among species. A scenario is put forward to explain the current-day distribution of the species and colour varieties and the observed clinal variation across the subbasin’s shoreline. Additionally, we observed that variation in shape was larger in populations from shallow shores whereas populations from steep shores were more variable in meristics. This difference is explained in terms of the different timescales at which small and large scale lake level fluctuations affected populations of littoral cichlids at steep and shallow shores.Conclusions
Our results showed meristics to be more evolutionary stable, and of higher taxonomic value for species delimitation in Tropheus, than linear measurements that describe shape. These results should be taken into account when interpreting morphological differences between populations of highly stenotypic species, such as littoral cichlids from the Great East African Lakes.27.
Six- and seven-band morphs have been identified in a cichlid, Cyphotilapia frontosa, that is endemic to Lake Tanganyika. These color morphs have allopatric distributions; the six-band morph is widespread in
the northern half of the lake while the seven-band morph is restricted to Kigoma on the east coast of the lake. Because no
specimens of the seven-band morph have been available for taxonomic study except for the holotype of C. frontosa, the taxonomic status of these morphs has not been discussed. In a recent survey at the lake, 21 specimens of the seven-band
morph were collected. A comparison of these with existing collection specimens of the six-band morph showed significant differences
in morphometric and meristic characters; however, because all characters largely overlapped between these morphs, they are
regarded as conspecific. 相似文献
28.
29.
Hydrobiologia - The Lake Edward system in Eastern Central Africa, including Lakes Edward and George and their associated rivers, is home to a species assemblage of endemic haplochromine cichlids.... 相似文献