Comúnmente conocidos como “arañas de mar”, los picnogónidos son un grupo artrópodos exclusivamente marinos. En México se han reportado 62 especies, presentes en casi todos estados costeros. Estos datos resultado, su gran mayoría, investigaciones extranjeras y estudios recientes recolectas esporádicas enfocadas a la fauna del meiobentos. El objetivo este trabajo es dar conocer ejemplares deposit...

Priapulus caudatus (phylum Priapulida) is a benthic marine predatory worm with a cosmopolitan distribution. In its digestive tract we detected symbiotic bacteria that were consistently present in specimens collected over 8 years from three sites at the Swedish west coast. Based on their 16S rRNA gene sequence, these symbionts comprise a novel genus of the order Rickettsiales (Alphaproteobacteri...

Nervous system and sensory structure morphologies provide useful information for reconstructing phylogenetic relationships among the Polychaeta, Annelida, and Arthropoda. With the more common use of indirect immunocytochemistry and laser scanning confocal microscopy methods, the detailed information available from morphological studies has increased. Despite this wealth of information, developi...

The Mixed-Lineage Leukemia gene (MLL/HRX/ALL1) encodes a large nuclear protein homologous to Drosophila trithorax that is required for the maintenance of HOX gene expression. MLL is cleaved at two conserved sites generating N320 and C180 fragments, which heterodimerize to stabilize the complex and confer its subnuclear destination. Here, we purify and clone the protease responsible for cleaving...

Myriapoda, a subphylum of Arthropoda, comprises four classes, Chilopoda, Diplopoda, Pauropoda, and Symphyla. While recent molecular evidence has shown that Myriapoda is monophyletic, the internal phylogeny, which is pivotal for understanding the evolutionary history of myriapods, remains unresolved. Here we report the results of phylogenetic analyses and estimations of divergence time and ances...

Cyanogenic glucosides are phytoanticipins known to be present in more than 2500 plant species. They are considered to have an important role in plant defense against herbivores due to bitter taste and release of toxic hydrogen cyanide upon tissue disruption. Some specialized herbivores, especially insects, preferentially feed on cyanogenic plants. Such herbivores have acquired the ability to me...

Acute toxicity of 4-nonylphenol (NP) was examined in six freshwater species from three phyla - platyhelminthes, arthropoda and mollusca. Values of the 48-hour LC(50) of NP for six species ranged from 20 to 508 ug/L and values of the 96-hour LC(50) for four species ranged from 120 to 457 ug/L. The most sensitive species tested was a water flea, Ceriodaphnia cornuta, with a 48-hour LC(50) of 20 m...

Gigantism is widespread among Palaeozoic arthropods, yet causal mechanisms, particularly the role of (abiotic) environmental factors versus (biotic) competition, remain unknown. The eurypterids (Arthropoda: Chelicerata) include the largest arthropods; gigantic predatory pterygotids (Eurypterina) during the Siluro-Devonian and bizarre sweep-feeding hibbertopterids (Stylonurina) from the Carbonif...