Ants from the Montnegre-Corredor Natural Park (NE Spain) with description of the male Lasius cinereus Seifert (Hymenoptera, Formicidae)

A survey was conducted on the myrmecofauna of this protected zone near Barcelona (NE Spain). A total of 50 species was found. Lasius lasioides (Emery) and Lasius cinereus Seifert are added to the fauna of Catalonia. The males of this latter species are described for the first time; their smaller size separates them from the otherwise similar males of L. grandis Forel. The head and scape are proportionately longer in L. cinereus. One sample of Lasius (Chthonolasius) was unusual since it contained two sharply distinct phenotypes differentiated by the pubescence, biometry and degree of flattening of appendages. One form is provisionally identified as L. umbratus (Nylander); the other form is tentatively associated with Lasius rabaudi Bondroit. The presence of the invasive Argentine ant (Linepithema humile Mayr) at one of the borders of the park calls for monitoring of its eventual spread and we suggest a rehabilitation of the area presently occupied by this ant. Key words: Ants, Formicidae, Lasius cinereus, Lasius lasioides, Chthonolasius, Male.A survey was conducted on the myrmecofauna of this protected zone near Barcelona (NE Spain). A total of 50 species was found. Lasius lasioides (Emery) and Lasius cinereus Seifert are added to the fauna of Catalonia. The males of this latter species are described for the first time; their smaller size separates them from the otherwise similar males of L. grandis Forel. The head and scape are proportionately longer in L. cinereus. One sample of Lasius (Chthonolasius) was unusual since it contained two sharply distinct phenotypes differentiated by the pubescence, biometry and degree of flattening of appendages. One form is provisionally identified as L. umbratus (Nylander); the other form is tentatively associated with Lasius rabaudi Bondroit. The presence of the invasive Argentine ant (Linepithema humile Mayr) at one of the borders of the park calls for monitoring of its eventual spread and we suggest a rehabilitation of the area presently occupied by this ant. Key words: Ants, Formicidae, Lasius cinereus, Lasius lasioides, Chthonolasius, Male.A survey was conducted on the myrmecofauna of this protected zone near Barcelona (NE Spain). A total of 50 species was found. Lasius lasioides (Emery) and Lasius cinereus Seifert are added to the fauna of Catalonia. The males of this latter species are described for the first time; their smaller size separates them from the otherwise similar males of L. grandis Forel. The head and scape are proportionately longer in L. cinereus. One sample of Lasius (Chthonolasius) was unusual since it contained two sharply distinct phenotypes differentiated by the pubescence, biometry and degree of flattening of appendages. One form is provisionally identified as L. umbratus (Nylander); the other form is tentatively associated with Lasius rabaudi Bondroit. The presence of the invasive Argentine ant (Linepithema humile Mayr) at one of the borders of the park calls for monitoring of its eventual spread and we suggest a rehabilitation of the area presently occupied by this ant. Key words: Ants, Formicidae, Lasius cinereus, Lasius lasioides, Chthonolasius, Male

L'Espectrometria de masses aplicada a la caracterització de materials

En aquest article hom pretén revisar en primer lloc, els principis de funcionament d'un espectròmetre de masses així com els principals desenvolupaments experimentals que aquesta tècnica ha assolit en l'actualitat. Per aquesta raó hom discutirà sobre diferents fonts d'ionització tant clàssiques (impacte electrònic, ionització química...) com d'altres dissenyades per a analitzar materials no volàtils. El concepte d'espectròmetre de doble enfocament també serà revisat. Hom introduirà els principis bàsics que permeten d'obtenir les anàlisi SIMS (Secondary Ion Mass Spectrometry) i els anomenats "ion imaging". Ha merescut una atenció especial la disposició FAB-CAD-MIKES (Fast Atom Bombardment – Collission Activated Decay- Mass Analysed Ion Kinetic Energy Spectrometry). També seran presentades algunes experiències realitzades amb aquestes tècniques.This paper reviews firstly the basis of a mass spectrometer and the main experimental developments reachead by this technique up to now. Different classical ionization sources (such as electron impact,chemical ionization ) and those developed for the analysis of non volatile materials as well as the concept of double focalization mass spectrometer will be discussed. Furthermore the principles of S.I.M.S. analysis and ion imaging, will be considered. Special attention will be devoted to the joint application of F.A.B.-C.A.D.-M.I.K.E.S. techniques. Finally, some experiences carried out with these techniques are reported

Prediction of enzyme function by combining sequence similarity and protein interactions

<p>Abstract</p> <p>Background</p> <p>A number of studies have used protein interaction data alone for protein function prediction. Here, we introduce a computational approach for annotation of enzymes, based on the observation that similar protein sequences are more likely to perform the same function if they share similar interacting partners.</p> <p>Results</p> <p>The method has been tested against the PSI-BLAST program using a set of 3,890 protein sequences from which interaction data was available. For protein sequences that align with at least 40% sequence identity to a known enzyme, the specificity of our method in predicting the first three EC digits increased from 80% to 90% at 80% coverage when compared to PSI-BLAST.</p> <p>Conclusion</p> <p>Our method can also be used in proteins for which homologous sequences with known interacting partners can be detected. Thus, our method could increase 10% the specificity of genome-wide enzyme predictions based on sequence matching by PSI-BLAST alone.</p

Physical and land-cover variables influence ant functional groups and species diversity along elevational gradients

Of particular importance in shaping species assemblages is the spatial heterogeneity of the environment. The aim of our study was to investigate the influence of spatial heterogeneity and environmental complexity on the distribution of ant functional groups and species diversity along altitudinal gradients in a temperate ecosystem (Pyrenees Mountains). During three summers, we sampled 20 sites distributed across two Pyrenean valleys ranging in altitude from 1,009 to 2,339 m by using pitfall traps and hand collection. The environment around each sampling points was characterized by using both physical and land-cover variables. We then used a self-organizing map algorithm (SOM, neural network) to detect and characterize the relationship between the spatial distribution of ant functional groups, species diversity, and the variables measured. The use of SOM allowed us to reduce the apparent complexity of the environment to five clusters that highlighted two main gradients: an altitudinal gradient and a gradient of environmental closure. The composition of ant functional groups and species diversity changed along both of these gradients and was differently affected by environmental variables. The SOM also allowed us to validate the contours of most ant functional groups by highlighting the response of these groups to the environmental and land-cover variables

Colony-level differences in the scaling rules governing wood ant compound eye structure

Differential organ growth during development is essential for adults to maintain the correct proportions and achieve their characteristic shape. Organs scale with body size, a process known as allometry that has been studied extensively in a range of organisms. Such scaling rules, typically studied from a limited sample, are assumed to apply to all members of a population and/or species. Here we study scaling in the compound eyes of workers of the wood ant, Formica rufa, from different colonies within a single population. Workers' eye area increased with body size in all the colonies showing a negative allometry. However, both the slope and intercept of some allometric scaling relationships differed significantly among colonies. Moreover, though mean facet diameter and facet number increased with body size, some colonies primarily increased facet number whereas others increased facet diameter, showing that the cellular level processes underlying organ scaling differed among colonies. Thus, the rules that govern scaling at the organ and cellular levels can differ even within a single population

The Evolution of Invasiveness in Garden Ants

It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects

Simplified Method to Predict Mutual Interactions of Human Transcription Factors Based on Their Primary Structure

Background: Physical interactions between transcription factors (TFs) are necessary for forming regulatory protein complexes and thus play a crucial role in gene regulation. Currently, knowledge about the mechanisms of these TF interactions is incomplete and the number of known TF interactions is limited. Computational prediction of such interactions can help identify potential new TF interactions as well as contribute to better understanding the complex machinery involved in gene regulation. Methodology: We propose here such a method for the prediction of TF interactions. The method uses only the primary sequence information of the interacting TFs, resulting in a much greater simplicity of the prediction algorithm. Through an advanced feature selection process, we determined a subset of 97 model features that constitute the optimized model in the subset we considered. The model, based on quadratic discriminant analysis, achieves a prediction accuracy of 85.39 % on a blind set of interactions. This result is achieved despite the selection for the negative data set of only those TF from the same type of proteins, i.e. TFs that function in the same cellular compartment (nucleus) and in the same type of molecular process (transcription initiation). Such selection poses significant challenges for developing models with high specificity, but at the same time better reflects real-world problems. Conclusions: The performance of our predictor compares well to those of much more complex approaches for predicting TF and general protein-protein interactions, particularly when taking the reduced complexity of model utilisation into account

Critical assessment of sequence-based protein-protein interaction prediction methods that do not require homologous protein sequences

<p>Abstract</p> <p>Background</p> <p>Protein-protein interactions underlie many important biological processes. Computational prediction methods can nicely complement experimental approaches for identifying protein-protein interactions. Recently, a unique category of sequence-based prediction methods has been put forward - unique in the sense that it does not require homologous protein sequences. This enables it to be universally applicable to all protein sequences unlike many of previous sequence-based prediction methods. If effective as claimed, these new sequence-based, universally applicable prediction methods would have far-reaching utilities in many areas of biology research.</p> <p>Results</p> <p>Upon close survey, I realized that many of these new methods were ill-tested. In addition, newer methods were often published without performance comparison with previous ones. Thus, it is not clear how good they are and whether there are significant performance differences among them. In this study, I have implemented and thoroughly tested 4 different methods on large-scale, non-redundant data sets. It reveals several important points. First, significant performance differences are noted among different methods. Second, data sets typically used for training prediction methods appear significantly biased, limiting the general applicability of prediction methods trained with them. Third, there is still ample room for further developments. In addition, my analysis illustrates the importance of complementary performance measures coupled with right-sized data sets for meaningful benchmark tests.</p> <p>Conclusions</p> <p>The current study reveals the potentials and limits of the new category of sequence-based protein-protein interaction prediction methods, which in turn provides a firm ground for future endeavours in this important area of contemporary bioinformatics.</p