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Taxonomic Range (taxonomic + range)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Analysis of the sugar-binding specificity of mannose-binding-type Jacalin-related lectins by frontal affinity chromatography , an approach to functional classification

FEBS JOURNAL, Issue 6 2008
Sachiko Nakamura-Tsuruta
The Jacalin-related lectin (JRL) family comprises galactose-binding-type (gJRLs) and mannose-binding-type (mJRLs) lectins. Although the documented occurrence of gJRLs is confined to the family Moraceae, mJRLs are widespread in the plant kingdom. A detailed comparison of sugar-binding specificity was made by frontal affinity chromatography to corroborate the structure,function relationships of the extended mJRL subfamily. Eight mJRLs covering a broad taxonomic range were used: Artocarpin from Artocarpus integrifolia (jackfruit, Moraceae), BanLec from Musa acuminata (banana, Musaceae), Calsepa from Calystegia sepium (hedge bindweed, Convolvulaceae), CCA from Castanea crenata (Japanese chestnut, Fagaceae), Conarva from Convolvulus arvensis (bindweed, Convolvulaceae), CRLL from Cycas revoluta (King Sago palm tree, Cycadaceae), Heltuba from Helianthus tuberosus (Jerusalem artichoke, Asteraceae) and MornigaM from Morus nigra (black mulberry, Moraceae). The result using 103 pyridylaminated glycans clearly divided the mJRLs into two major groups, each of which was further divided into two subgroups based on the preference for high-mannose-type N-glycans. This criterion also applied to the binding preference for complex-type N-glycans. Notably, the result of cluster analysis of the amino acid sequences clearly corresponded to the above specificity classification. Thus, marked correlation between the sugar-binding specificity of mJRLs and their phylogeny should shed light on the functional significance of JRLs. [source]

The evolutionary ecology of senescence

FUNCTIONAL ECOLOGY, Issue 3 2008
P. Monaghan
Summary 1Research on senescence has largely focused on its underlying causes, and is concentrated on humans and relatively few model organisms in laboratory conditions. To understand the evolutionary ecology of senescence, research on a broader taxonomic range is needed, incorporating field, and, where possible, longitudinal studies. 2Senescence is generally considered to involve progressive deterioration in performance, and it is important to distinguish this from other age-related phenotypic changes. We outline and discuss the main explanations of why selection has not eliminated senescence, and summarise the principal mechanisms thought to be involved. 3The main focus of research on senescence is on age-related changes in mortality risk. However, evolutionary biologists focus on fitness, of which survival is only one component. To understand the selective pressures shaping senescence patterns, more attention needs to be devoted to age-related changes in fecundity. 4Both genetic and environmental factors influence the rate of senescence. However, a much clearer distinction needs to be drawn between life span and senescence rate, and between factors that alter the overall risk of death, and factors that alter the rate of senescence. This is particularly important when considering the potential reversibility and plasticity of senescence, and environmental effects, such as circumstances early in life. 5There is a need to reconcile the different approaches to studying senescence, and to integrate theories to explain the evolution of senescence with other evolutionary theories such as sexual and kin selection. [source]

rRNA PROBES FOR IDENTIFICATION AND CHARACTERIZATION OF MARINE PHYTOPLANKTON: THEIR POTENTIAL APPLICATION FOR DNA MICROCHIPS

JOURNAL OF PHYCOLOGY, Issue 2001
Article first published online: 24 SEP 200
Groben R., Lange, M. & Medlin, L. K. Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany A fast and reliable identification of nano- and picoplankton by light microscopy is often difficult because of the lack of usable morphological characteristics, whereas electron microscopy and biochemical methods are very time consuming. Identification of toxic algae also requires a great deal of taxonomic experrtise so that false positives are not recorded. One solution is to use taxon specific rRNA probes. For this purpose we designed probes for phytoplankton taxa, including toxic algae. These probes were either labelled with Digoxigenin (DIG) and used in DNA dot blot experiments, or labelled with fluorochromes and used in whole-cell hybridisations with fluorescence microscopy or flow cytometric detection. Specific probes could be used over a broad taxonomic range from higher groups (i.e. the class of dinoflagellates) to species level (i.e. Prorocentrum lima). These probes were be used in the EU MAST project AIMS for the development of an automated identification system for marine phytoplankton in combination with flow cytometry and artificial neural networks (ANNs), in the EU MAST DETAL and in the German national project (TEPS) for the development of an early warning system for harmful algal blooms. Results using Digoxigenin (DIG)-labelled probes on picoplankton samples taken from several water bodies indicate that hierarchial re-probing of spotted samples can be achieved and this suggests that probes can be adapted to DNA microchips. Preliminary field results for a hand-held DNA microchip reader are presented. This work was supported by the German BMBF TEPS 03F0161 and the EU AIMS MAS3-CT97-0080 and EU DETAL Q5RS-2000-30778 projects. [source]

A PCR-based method for diet analysis in freshwater organisms using 18S rDNA barcoding on faeces

MOLECULAR ECOLOGY RESOURCES, Issue 1 2010
EMMANUEL CORSE
Abstract The development of DNA barcoding from faeces represents a promising method for animal diet analysis. However, current studies mainly rely on prior knowledge of prey diversity for a specific predator rather than on a range of its potential prey species. Considering that the feeding behaviour of teleosts may evolve with their environment, it could prove difficult to establish an exhaustive listing of their prey. In this article, we extend the DNA barcoding approach to diet analysis to allow the inclusion of a wide taxonomic range of potential prey items. Thirty-four ecological clade-specific primer sets were designed to cover a large proportion of prey species found in European river ecosystems. Selected primers sets were tested on isolated animal, algal or plant tissues and thereafter on fish faeces using nested PCR to increase DNA detection sensitivity. The PCR products were sequenced and analysed to confirm the identity of the taxa and to validate the method. The methodology developed here was applied to a diet analysis of three freshwater cyprinid species that are assumed to have similar feeding behaviour [Chondrostoma toxostoma toxostoma (Vallot 1837), Chondrostoma nasus nasus (Linnaeus, 1758) and Barbus barbus, (Linneaus 1758)]. These three species were sampled in four different hydrographic basins. Principal Component Analysis based on prey proportions identified distinct perilithon grazer and benthophagous behaviours. Furthermore, our results were consistent with the available literature on feeding behaviour in these fish. The simplicity of the PCR-based method and its potential generalization to other freshwater organisms may open new perspectives in food web ecology. [source]