Light induced larval release of a colonial ascidian

Larval release and photobehavior were studied in the colonial ascidian Polyandrocarpa zorritensis. The test hypothesis was that if larval release is induced by light, then larvae should be attracted to settlement areas where light is sufficient for larval release. Light induced larval release but the time course varied with light intensity. As the intensity of either sunlight or blue-green light decreased (1) the time until the beginning of larval release (latency) became longer, (2) the mean time of larval release increased, and (3) the time interval over which larvae were released increased. The threshold light intensity to induce larval release in blue-green light (8.75x10(12) photons cm(-2) s(-1)) was lower than that in sunlight (3.6x10(13) photons cm(-2) s(-1)). Light induced larval release was not affected by currents up to 15 cm s(-1). Larvae aggregate in light when given a choice between light and dark. This response did not vary with larval age. The lowest light intensity, at which larvae could distinguish between light and dark was 5.0x10(12) photons cm(-2) s(-1) in blue-green light and 2.9x10(14) photons cm(-2) s(-1) in sunlight. Thus, the hypothesis is supported because larvae are attracted to areas where light intensity is sufficient for larval release.     

Isolation of isoproturon-degrading bacteria from treated soil via three different routes

Three different isolation routes (flask enrichment/flask degradation assay, flask enrichment/microplate degradation assay, MPN assay/microplate degradation assay) were used to obtain pure cultures of bacteria which degraded isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) as sole carbon and nitrogen source in a mineral salts medium from a field soil treated with isoproturon in the laboratory. All three isolation routes were successful, but the microplate assay of degradation was more successful than the flask assay. Characterization of 36 isolates indicated that they formed 16 distinct phenotypes (10 Gram-positive phenotypes, six Gram-negative phenotypes) which are likely to represent distinct species. Low concentrations of the degradation product 3-(4-isopropylphenyl)-1-methylurea (IPPMU) were occasionally found in the culture solutions. When provided as the sole source of carbon and nitrogen, the monomethyl degradation product was itself rapidly degraded by several of the isolates. Some isolates were also able to use the demethylated degradation product 3-(4-isopropylphenyl)-urea (IPPU) as sole source of carbon and nitrogen, although there was occasionally an extended lag-phase before rapid degradation commenced. One isolate was particularly active and degraded isoproturon, the monomethyl and demethylated degradation products of isoproturon, and demethylated the related phenylureas diuron and linuron.     

Interactions ofCandida albicans with bacteria and salivary molecules in oral biofilms

The yeastCandida albicans coaggregates with a variety of streptococcal species, an interaction that may promote oral colonization by yeast cells.C. albicans andCandida tropicalis are the yeasts most frequently isolated from the human oral cavity and our data demonstrate that both these species bind toStreptococcus gordonii NCTC 7869 while two otherCandida species (Candida krusei andCandida kefyr) do not. Adherence ofC. albicans was greatest when the yeast had been grown at 30° C to mid-exponential growth phase. For 21 strains ofC. albicans there was a positive correlation between the ability to adhere toS. gordonii and adherence to experimental salivary pellicle. Whole saliva either stimulated or slightly inhibited adherence ofC. albicans toS. gordonii depending on the streptococcal growth conditions. The results suggest that the major salivary adhesins and coaggregation adhesins ofC. albicans are co-expressed.     

CC chemokine receptor-3 (CCR3) antagonists: improving the selectivity of DPC168 by reducing central ring lipophilicity

DPC168, a benzylpiperidine-substituted aryl urea CCR3 antagonist evaluated in clinical trials, was a relatively potent inhibitor of the 2D6 isoform of cytochrome P-450 (CYP2D6). Replacement of the cyclohexyl central ring with saturated heterocycles provided potent CCR3 antagonists with improved selectivity against CYP2D6. The favorable preclinical profile of DPC168 was maintained in an acetylpiperidine derivative, BMS-570520.     

Identification of the mouse killer immunoglobulin-like receptor-like (<Emphasis Type="Italic">Kirl</Emphasis>) gene family mapping to Chromosome X

Natural killer (NK) inhibitory receptors, which recognize major histocompatability complex (MHC) proteins in humans, are known as killer Ig-like receptors (KIRs) and are encoded by a multi-gene immunoglobulin (Ig) superfamily. In a screen for genes differentially expressed in the mouse thymus, we discovered the first close rodent homologue of the NK receptor KIR family, which we named KIR- Like (Kirl). KIRL1 shares 40% amino acid identity with primate KIR family members, with the majority of the homology contained within the Ig-like ectodomains. KIRL1 is more similar to the KIRs than to any other known member of the Ig domain-containing leukocyte receptor superfamily. This highly significant homology suggests that the KIR family did not arise independently in primates, as has been previously suggested, but rather evolved from a primordial gene already present in the common rodent/primate ancestor. KIRL1 lacks the cytoplasmic protein motifs that mediate inhibition in KIRs (immunoregulatory tyrosine inhibiting motif, ITIM); KIRL1 also lacks the transmembrane activation signature (a conserved K residue involved in association with the immunoregulatory tyrosine activating motif-containing DAP12 molecule) found in some KIRs. Nevertheless, we hypothesize that Kirl1 is functional, for the following reasons: (1) Kirl1 mRNA is expressed at high levels in immature thymocytes; (2) Kirl1 is regulated during thymocyte development; (3) KIRL1 protein is detected in thymus. We also show that the mouse genome contains a closely related, transcribed gene, which we name Kirl2. Kirl2 encodes a KIR-like molecule with three Ig-like domains and also lacks tyrosine-based immunoregulatory motifs in its cytoplasmic region.