No abstract

A large collection of clionaid sponges collected in 58 different localities from the Pacific coast of Mexico was studied, and 15 species belonging to four genera were identified. Six species are new to science: in the genus Cliona, C. papillae sp. nov. and C. vallartense sp. nov.; in the genus Thoosa, T. calpulli sp. nov. and T. mismalolli sp. nov.; and in the genus Spheciospongia, S. ruetzleri sp. nov. and S. incrustans sp. nov. The new combinations Cliona californiana (de Laubenfels, 1932) comb. nov. and Cliona raromicrosclera (Dickinson, 1945) comb. nov. are also proposed. Pseudosuberites pseudos is considered to be synonymous to Cliona californiana. In addition, the validity of Pione mazatlanensis (Hancock, 1867) is also considered. Other Cliona species identified are Cliona vermifera Hancock, 1867, Pione carpenteri (Hancock, 1867 as Cliona carpenteri), C. amplicavata Rützler, 1974, Cliona flavifodina Rützler, 1974, and Cliona euryphylla Topsent, 1887.Cliona amplicavata and C. flavifodina are recorded for the first time in the Pacific Ocean and C. euryphylla for the east Pacific Ocean. The systematics, taxonomy and distribution of all these species are included and detailed species descriptions are provided based on newly collected material and previous descriptions from the literature. Discussions on problematic taxonomic issues are also presented, and the most useful parameters to differentiate species are highlighted. In addition, the morphology of the spirasters has been studied through SEM analysis, and the main characteristics have been evaluated from a taxonomic point of view in order to discriminate between species.

Yeasts within the Saccharomyces sensu stricto cluster can produce different killer toxins. Each toxin is encoded by a medium size (1.5–2.4 Kb) M dsRNA virus, maintained by a larger helper virus generally called L-A (4.6 Kb). Different types of L-A are found associated to specific Ms: L-A in K1 strains and L-A-2 in K2 strains. Here, we extend the analysis of L-A helper viruses to yeasts other than S. cerevisiae, namely S. paradoxus, S. uvarum and S. kudriavzevii. Our sequencing data from nine new L-A variants confirm the specific association of each toxin-producing M and its helper virus, suggesting co-evolution. Their nucleotide sequences vary from 10% to 30% and the variation seems to depend on the geographical location of the hosts, suggesting cross-species transmission between species in the same habitat. Finally, we transferred by genetic methods different killer viruses from S. paradoxus into S. cerevisiae or viruses from S. cerevisiae into S. uvarum or S. kudriavzevii. In the foster hosts, we observed no impairment for their stable transmission and maintenance, indicating that the requirements for virus amplification in these species are essentially the same. We also characterized new killer toxins from S. paradoxus and constructed “superkiller” strains expressing them.