Cribrilinids (Bryozoa, Cheilostomata) associated with deep-water coral habitats at the Great Bahama Bank slope (NW Atlantic), with description of new taxa

Four cribrilinid bryozoans associated with deep-water corals (578-682 m depth) from the Great Bahama Bank slope, are described, two of them are new. The generic allocation of some species prompted us to raise the subgenera Puellina, Cribrilaria, and Glabrilaria to genus rank. The new combination Cribrilaria saginata (Winston, 2005) n. comb. is proposed. Genus Glabrilaria is reported from the NW Atlantic for the first time based on the description of Glabrilaria hirsuta Rosso n. sp. and Glabrilaria polita Rosso n. sp. The new genus Teresaspis Rosso n. gen. is erected, and Teresaspis lineata (Canu Bassler, 1928) n. comb. is proposed as its type species. The new genus Harmelinius Rosso n. gen. is erected for Cribrilina uniserialis (Harmelin, 1978). Both genera have uniserial colonies formed by slightly caudate zooids with extensive gymnocyst and a frontal shield of flattened costae. Teresaspis lineata n. comb., however, has costae with pelmatidia that are connected by few intercostal bridges and separated by intercostal spaces, four orificial costa-like processes with the proximal pair arching above the orifice, hyperstomial acleithral ovicells with a pseudoporous ooecium formed by the distal zooid or a kenozooid, two types of kenozooids (large with costate frontal shield and small with smooth shield and central opesia), and an ancestrula with costate frontal shield. Avicularia are apparently absent in this species. In contrast, the type species of Harmelinius Rosso n. gen. has costae lacking pelmatidia and which are separated by slit-like intercostal spaces. The hyperstomial cleithral ovicells have smooth ooecia with a median suture and without pseudopores, and are formed by a distal kenozooid associated with a small avicularium. Additional paired oral avicularia are occasionally present, as are large kenozooids with a central opesia. Oral spines or spine-like processes are absent. Taxonomy of the above reported cribrilinid genera is discussed in detail together with the geographic distribution of all mentioned taxa.

Chromosome mapping and organization of the human beta-galactoside alpha 2,6-sialyltransferase gene. Differential and cell-type specific usage of upstream exon sequences in B-lymphoblastoid cells

The human beta-galactoside alpha 2,6-sialyltransferase (EC 2.4.99.1) (SiaT-1) gene is localized to human chromosome 3 (q21-q28) by Southern analysis of somatic cell hybrids and by in situ hybridization of metaphase chromosomes. Comparative analysis between the human and the previously reported rat SiaT-1 genomic sequences demonstrates precise conservation of the intron/exon boundaries throughout the coding domains. Furthermore, there is extensive inter-species sequence similarity in some of the exons that contain information only for the 5'-leader regions. Human genomic sequences were also analyzed to reconcile reported differences in the 5'-untranslated region in SiaT-1 mRNAs. In cultured cell lines of the B-lineage, Reh, Nalm-6, Jok-1, Ball-1, Daudi, and Louckes, the study demonstrates that three upstream exons, Exons(Y+Z) and Exon(X), are mutually exclusively utilized, resulting in at least two distinct populations of SiaT-1 mRNA being synthesized. None of these exons is present in the SiaT-1 mRNA isotype expressed in HepG2 human hepatoma cells. In all B-lymphoblastoid cell lines examined, the basal level SiaT-1 mRNA is maintained by the expression of an isotype containing the Exons(Y+Z) sequence. The slightly smaller SiaT-1 mRNA, which contains the Exon(X) sequence but not Exons(Y+Z) sequence, is synthesized at a high level and found only in Jok-1, Daudi, and Louckes, the cell lines with mature B-cell phenotype. The study also provides further evidence that induced SiaT-1 expression accompanies the appearance of CDw75, a putatively sialylated cell surface epitope and a marker of human mature B-lymphocytes. The SiaT-1 induction is the result of the appearance of a novel form of SiaT-1 mRNA isotype.

Non-contacted bases affect the affinity of synthetic P22 operators for P22 repressor

The affinity of synthetic P22 operators for P22 repressor varies with the base sequence at the operator's center. At 100 mM KCl, the affinity of these operators for P22 repressor varies over a 10-fold range. Dimethylsulfate protection experiments indicate that the central bases of the P22 operator are not contacted by the repressor. The KD for the complex of P22 repressor with an operator bearing central T-A bases (9T) increases less than 2-fold between 50 and 200 mM KCl, whereas the KD for the complex of repressor with an operator bearing central C-G bases (9C) increases 10-fold in the same salt range. The DNase I cleavage patterns of both bound and unbound P22 operators also vary with central base sequence. The DNase I pattern of the repressor-9C operator complex changes markedly with salt concentration, whereas that of the 9T operator-repressor complex does not. These changes in nuclease digestion pattern thereby mirror the salt-dependent changes in the P22 operator's affinity for repressor. P22 repressor protects the central base pair of the 9T operator from cleavage by the intercalative cleavage reagent Cu(I)-phenanthroline, while repressor does not protect the central bases of the 9C operator. Together these data indicate that central base pairs affect P22 operator strength by altering the structure of the unbound operator and the repressor-operator complex.