Multicellular Ascomycetous Fungal Genomes Contain More Than 8000 Genes

Fungi comprise a large monophyletic group of uni- and multicellular eukaryotic organisms in which many species are of economic or medical importance. Fungal genomes are variable in size (13–42 Mb), and multicellular species support true spatial and temporal cell-type-specific regulation of gene expression. In a 38.8-kbAspergillus nidulanscontiguous genomic DNA region, a transposable element and 12 potential genes were identified, 7 similar to genes in other organisms. This observation is consistent with the prediction that multicellular ascomycetous fungi harbor 8000–9000 genes in a 36-Mb average genome. Thus, the genomic DNA sequence of filamentous fungi will provide substantial amounts of genetic and functional information that is not available in yeast, for the human and other metazoan minimal gene complement.     

Dietary immunoassay of pelagic nemerteans by use of cross-reacting polyclonal antibodies: preliminary findings

With little data on the diet of pelagic nemerteans, apreliminary immunoassay survey of the gut contents ofthree species from the Pacific Ocean was performedusing non-specific, cross-reacting polyclonalantibodies. Results suggest that Nectonemertescf. mirabilis, Phallonemertes cf. murrayi, and Cuneonemertes elongata containedsomewhat different types of prey. Worms elicitedstrong responses when probed with antibodies tosquid-like mollusks and to mysids and shrimp. Heteropods are more likely ingested than pteropods. Additional studies must be done to confirm thesehighly suggestive results.     

Reproductive biology of several species of recently collected pelagic nemerteans

The reproductive biology and morphology of six polystiliferous and onemonostiliferous species of pelagic nemerteans was studied in specimensrecently collected off California. Depth distributions for these specimensranged from 250 m to 3250 m, with most specimens obtained between 700 m and1750 m. Length of sexually mature individuals ranged from 2 mm for themonostiliferan to 61 mm for a male Phallonemertes cf. murrayi. Among P. cf.murrayi and Nectonemertes cf. mirabilis, which yielded the largest specimensstudied, mature males were larger than mature females and mature animalswere larger than those in which gonads were not apparent. Females typicallyoutnumbered males, although N. cf. mirabilis approached a 1:1 sex ratio. Inthe polystiliferans studied by light microscopy, accessory ovarian cellsappeared to translocate yolk or yolk precursors to oocytes via cytoplasmicbridges, a mechanism typically associated with nurse cells and notpreviously reported from nemerteans. Mature oocytes 0.5–1 mm indiameter were common, making them very large compared to those of benthicnemerteans. Sperm possessed elongated heads and nuclei. In general, thepelagic nemerteans studied appeared: a) to produce relatively few maturegametes at a time, b) spawn in close proximity to each other, c) undergoiteroparous reproduction, and d) display moderately long-lived life cycles.In addition, data for P. cf. murrayi and possibly N. cf. mirabilisdemonstrates potential seasonal peaks in reproductive activity.