A multidisciplinary approach to the systematics of Proteocephalus macrocephalus (Creplin, 1825) (Cestoda: Proteocephalidae)

The tapeworm Proteocephalus macrocephalus (Creplin, 1825), a parasite of the eel Anguilla anguilla, was characterised using morphological and genetic characters. The species is morphologically typified mainly by features of the scolex (i.e. shape and size of an apical organ which is formed early during the development in an intermediate host) and strobila (i.e. regularly rectangular proglottides, morphology of the vagina and anterior position of the seminal receptacle). Genetically, P. macrocephalus was compared with two congeners, P. percae and P. exiguus. Characters enabling differentiation of P. macrocephalus were as follows: fixed allelic differences at Got, Pgm and Gapdh loci, metrical features of chromosomes Nos 1, 2 and 7, and species-specific fragments obtained by RAPD method using 13 random primers.     

A multidisciplinary approach to discriminating different taxa in the species complex Pachycondyla villosa (Formicidae)

A multidisciplinary approach provides new evidence that strongly supports the differentiation of three taxa previously confounded in a single species, Pachycondyla villosa . All specimens studied were collected in the same location at Ilhéus, Bahia, Brazil. Bivariate plots of petiole heights vs. petiole lengths and isozyme patterns clearly differentiate the three taxa. Chain lengths and chemical structures of cuticular hydrocarbons are characteristic of each taxon. This congruent evidence shows that there are three different valid species. Ecological hypotheses are discussed to explain the benefits of these species remaining sympatric. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 249–259.     

Molecular approach to the systematics of European Tortricini (Lepidoptera: Tortricidae)

Tortricini is a cosmopolitan tribe of the subfamily Tortricinae of the lepidopteran family Tortricidae. The most recent systematic of Tortricini are based on the external morphology of imagines and the structure of their genital organs. The present paper is the first comparative molecular study of the representatives of this tribe. We examined DNA variation in a 606 bp fragment of COI mtDNA obtained from 23 species of Tortricini and two representatives of other tribes (Archips podanus of Archipini and Aethes hartmanniana of Cochylini). The position of Spatalistis, Tortrix, Aleimma and Acleris, and some groupings of species within Acleris were confirmed by molecular data, including the synonymization of Croesia and Phylacophora with Acleris. The positions of a few groupings of the Acleris species remain unresolved.     

Human DNA helicase B (HDHB) binds to replication protein A and facilitates cellular recovery from replication stress

Maintenance of genomic stability in proliferating cells depends on a network of proteins that coordinate chromosomal replication with DNA damage responses. Human DNA helicase B (HELB or HDHB) has been implicated in chromosomal replication, but its role in this coordinated network remains undefined. Here we report that cellular exposure to UV irradiation, camptothecin, or hydroxyurea induces accumulation of HDHB on chromatin in a dose- and time-dependent manner, preferentially in S phase cells. Replication stress-induced recruitment of HDHB to chromatin is independent of checkpoint signaling but correlates with the level of replication protein A (RPA) recruited to chromatin. We show using purified proteins that HDHB physically interacts with the N-terminal domain of the RPA 70-kDa subunit (RPA70N). NMR spectroscopy and site-directed mutagenesis reveal that HDHB docks on the same RPA70N surface that recruits S phase checkpoint signaling proteins to chromatin. Consistent with this pattern of recruitment, cells depleted of HDHB display reduced recovery from replication stress.     

Phylogenetic and expression analysis of the basic helix-loop-helix transcription factor gene family: genomic approach to cellular differentiation

A phylogenetic analysis of seven different species (human, mouse, rat, worm, fly, yeast, and plant) utilizing all (541) basic helix-loop-helix (bHLH) genes identified, including expressed sequence tags (EST), was performed. A super-tree involving six clades and a structural categorization involving the entire coding sequence was established. A nomenclature was developed based on clade distribution to discuss the functional and ancestral relationships of all the genes. The position/location of specific genes on the phylogenetic tree in relation to known bHLH factors allows for predictions of the potential functions of uncharacterized bHLH factors, including EST's. A genomic analysis using microarrays for four different mouse cell types (i.e. Sertoli, Schwann, thymic, and muscle) was performed and considered all known bHLH family members on the microarray for comparison. Cell-specific groups of bHLH genes helped clarify those bHLH genes potentially involved in cell specific differentiation. This phylogenetic and genomic analysis of the bHLH gene family has revealed unique aspects of the evolution and functional relationships of the different genes in the bHLH gene family.     

Characterization of the primary sonic muscles in Carapus acus (Carapidae): a multidisciplinary approach

Sound production in carapid fishes results from the action of extrinsic muscles that insert into the swim bladder. Biochemical, histochemical and morphological techniques were used to examine the sonic muscles and compare them with epaxial muscles in Carapus acus. Sonic fibres are thicker than red and thinner than white epaxial fibres, and sonic fibres and myofibrils exhibit an unusual helicoidal organization: the myofibrils of the centre are in a straight line whereas they are more and more twisted towards the periphery. Sonic muscles have both features of red (numerous mitochondria, high glycogen content) and white (alkali-stable ATPase) fibres. They differ also in the isoforms of the light chain (LC3) and heavy chain (HC), in having T tubules at both the Z-line and the A-I junction and in a unique parvalbumin isoform (PAI) that may aid relaxation. All these features lead to the expression of two assumptions about sound generation: the sonic muscle should be able to perform fast and powerful contractions that provoke the forward movement of the forepart of the swim bladder and the stretching and "flapping" of the swim bladder fenestra; the helicoidal organization allows progressive drawing of the swim bladder fenestra which emits a sound when rapidly released in a spring-like manner.     

TOR signaling: an odyssey from cellular stress to the cell growth machinery

The target of rapamycin (TOR) protein kinase is centrally involved in the coordination of cell growth and proliferation with the availability of growth factors and nutrients. Two recent reports have illuminated a mechanism whereby hypoxic stress dampens TOR signaling in metazoan cells.     

An integrative multidisciplinary approach to understanding cryptic divergence in Brazilian species of the Anastrepha fraterculus complex (Diptera: Tephritidae)

An integrative multidisciplinary approach was used to delimit boundaries among cryptic species within the Anastrepha fraterculus complex in Brazil. Sexual compatibility, courtship and sexual acoustic behaviour, female morphometric variability, variation for the mitochondrial gene COI, and the presence of Wolbachia were compared among A. fraterculus populations from the Southern (Vacaria, Pelotas, Bento Gonçalves, São Joaquim) and Southeastern (Piracicaba) regions of Brazil. Our results suggest full mating compatibility among A. fraterculus populations from the Southern region and partial pre‐zygotic reproductive isolation of these populations when compared with the population from the Southeastern region. A. fraterculus populations from both regions differed in the frequency of courtship displays and aspects of the calling phase and mounting acoustic signal. Morphometric analysis showed differences between Southern region and Southeastern region samples. All populations analyzed were infected with Wolbachia. The trees generated from the COI sequencing data are broadly congruent with the behavioural and morphometric data with the exception of one Southern population. The likely mechanisms by which A. fraterculus populations might have diverged are discussed in detail based on behavioural, morphometric, molecular genetics, and biogeographical studies.     

Gastrointestinal stromal tumors (GISTs): from science to targeted therapy

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. GISTs represent a distinct category of tumors characterized by oncogenic mutations of the KIT receptor tyrosine kinase in a majority of patients. KIT is useful not only for the diagnosis but also for targeted therapy of this disease. Imatinib, a tyrosine kinase inhibitor, is widely used in advanced and metastatic GISTs. This agent revolutionized the treatment strategy of advanced disease and is being tested in the neoadjuvant and adjuvant settings with encouraging results. New therapeutic agents like sunitinib have now been approved, enriching the treatment scenario for imatinib-resistant GISTs. The present review reports on the peculiar characteristics of this disease through its biology and molecular patterns, focusing on the predictive value of KIT mutations and their correlation with clinical outcome as well as on the activity of and resistance to approved targeted drugs.     

A multidisciplinary approach to the definition of species boundaries in branching species of the coral genus Psammocora (Cnidaria, Scleractinia)

The Indo-Pacific coral genus Psammocora Dana (1 846) has never been formally revised, and its phylogeny has only been partially explored. Several synonymies have been proposed for the 11 nominal species which have highly plastic branching growth forms. In the present study, the definition of genetic and morphologic boundaries among three currently recognized branching morpho-species, Psammocora stellata , Psammocora contigua and Psammocora obtusangula , is addressed through a joint morphometric and molecular study using corallite and branch measurements, and a portion of the β-tubulin gene as a marker. The results show a morphological and partial phylogenetic distinction between P. stellata specimens and a complex composed of P. contigua and P. obtusangula , which is interpreted as a synonym species of P. contigua. Among the factors that could be responsible for the lack of reciprocal monophyly of the three species, hybridization is considered the most likely, due to the presence of interspecific recombinant sequences. Type material of nominal species of branching Psammocora is examined and classified based on genetically defined groups, and compared with synonym in the literature. Among the morphological characters used, corallite variables were best for discriminating between the two lineages and allow recognition of putative hybrid specimens. Psammocora stellata is reported for the first time in the western Indian Ocean (Mayotte), thus greatly extending its known distribution range. Finally, a hybrid swarm is identified in the Arabo-Persian Gulf, while no genetic structure is detected elsewhere in the Indo-Pacific region.     

Dynamics and regulation of the stress response: meeting report on the stress response and molecular chaperones from Kyoto

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