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Influenza B viruses (IBV) are responsible for a considerable part of the burden caused by influenza virus infections. Since their emergence in the 1980s, the Yamagata and Victoria antigenic lineages of influenza B circulate in alternate patterns across the globe. Furthermore, their evolutionary divergence and the appearance of new IBV subclades complicates the prediction of future influenza vaccines compositions. It has been proposed that the addition of the neuraminidase (NA) antigen could potentially induce a broader protection and compensate for hemagglutinin (HA) mismatches in the current vaccines. Here we show that anti-NA and -HA sera against both Victoria and Yamagata lineages have limited inter-lineage cross-reactivity. When transferred to mice prior to infection with a panel of IBVs, anti-NA sera were as potent as anti-HA sera in conferring protection against homologous challenge and, in some cases, conferred superior protection against challenge with heterologous IBV strains.

The pennate diatom Seminavis robusta, characterized by an archetypical diatom life cycle including a heterothallic mating system, is emerging as a model system for studying the molecular regulation of the diatom cell and life cycle. One of its main advantages compared with other diatom model systems is that sexual crosses can be made routinely, offering unprecedented possibilities for forward genetics. To date, nothing is known about the genetic basis of sex determination in diatoms. Here, we report on the construction of mating type-specific linkage maps for S. robusta, and use them to identify a single locus sex determination system in this diatom. We identified 13 mating type plus and 15 mating type minus linkage groups obtained from the analysis of 463 AFLP markers segregating in a full-sib family, covering 963.7 and 972.2 cM, respectively. Five linkage group pairs could be identified as putative homologues. The mating type phenotype mapped as a monogenic trait, disclosing the mating type plus as the heterogametic sex. This study provides the first evidence for a genetic sex determining mechanism in a diatom.

We report on the construction of sex-specific linkage maps, the identification of sex-linked markers and the genome size estimation for the brine shrimp Artemia franciscana. Overall, from the analysis of 433 AFLP markers segregating in a 112 full-sib family we identified 21 male and 22 female linkage groups (2n = 42), covering 1,041 and 1,313 cM respectively. Fifteen putatively homologous linkage groups, including the sex linkage groups, were identified between the female and male linkage map. Eight sex-linked AFLP marker alleles were inherited from the female parent, supporting the hypothesis of a WZ-ZZ sex-determining system. The haploid Artemia genome size was estimated to 0.93 Gb by flow cytometry. The produced Artemia linkage maps provide the basis for further fine mapping and exploring of the sex-determining region and are a possible marker resource for mapping genomic loci underlying phenotypic differences among Artemia species.