Structure assignment of lucentamycin E and revision of the olefin geometries of the marine-derived lucentamycins.
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A new lucentamycin analogue, lucentamycin E (5), was isolated from the culture broth of the marine-derived actinomycete Nocardiopsis lucentensis, strain CNR-712. The absolute stereostructure of 5 was assigned by comprehensive analyses of NMR data and by application of the advanced Marfey's method. The planar structure of 5 was analogous to lucentamycins A-D, whereas the olefin geometry of the 3-methyl-4-ethylideneproline moiety was found to be E, opposite of that previously reported. Consequently, a reinvestigation of the olefin geometries of the 3-methyl-4-ethylideneproline residues of lucentamycins A-D showed that the olefin geometries of the substituted proline functionalities must be revised to (2S,3R,E)-3-methyl-4-ethylideneproline. (+info)
Light and vision in the deep-sea benthos: I. Bioluminescence at 500-1000 m depth in the Bahamian islands.
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Preparing for national implementation of an evidence-based, effective HIV prevention program among bahamian sixth-grade students.
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Using data from the preparatory phase prior to national implementation of an effective HIV prevention program (Focus on Youth in the Caribbean; FOYC) in all Bahamian government sixth-grade classes, we describe (1) actual FOYC implementation, (2) factors that influenced implementation, and (3) the relationship of implementation with intervention outcome. Six elementary schools (with 17 grade six classrooms) were selected to participate in the preparatory phase. The 17 teachers were invited to attend a training workshop, coordinate administration of questionnaires to the students, teach the 10 sessions of FOYC and complete self-assessment checklists. A total of 395 students submitted baseline and 311 students submitted year-end questionnaires. Thirteen teachers initiated FOYC; five completed all 10 sessions. Implementation of FOYC was not related to teacher FOYC workshop experience but did cluster by school. There were significant positive correlations between improved student knowledge of HIV/AIDS, protective health skills, perceived parental monitoring and reduced risk behaviours with the number of FOYC sessions delivered. Implementation was impeded by logistics issues, structural issues with the measures, and comfort-level issues, most of which can be addressed for national implementation. Degree of FOYC implementation is correlated with positive student outcomes. (+info)
Multiple fitness peaks on the adaptive landscape drive adaptive radiation in the wild.
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Complex movements, philopatry and expanded depth range of a severely threatened pelagic shark, the oceanic whitetip (Carcharhinus longimanus) in the western North Atlantic.
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Color pattern variation in a shallow-water species of opisthobranch mollusc.
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The color pattern of benthic opisthobranch sea slugs (Mollusca: Gastropoda) appears to play an important defensive role, and numerous species seem to have aposematic (warning) colorations. Color pattern is an important trait for opisthobranch identification-this conclusion is based on the assumption that most species have limited color variation. For those species in which color variation is recognized, the reasons for the variation remain unknown. In this paper we study Philinopsis pusa, a benthic putative species of opisthobranch sea slug with a broad range of color pattern. Lighter individuals appear to be camouflaged on the white sand environment in which the animals are typically found, whereas darker individuals appear conspicuously different from their background. Because of its broad color variation, P. pusa has been subdivided into different species. Animals were collected and observed in the Bahamas during a 6-year span. The color pattern of the specimens was subjectively classified into five phenotypic classes. Two mitochondrial genes (16S, CO1) were sequenced from 41 specimens. The association between color pattern, body length, burrowing escaping behavior, and the genetic structure of the population was investigated. We found two genetically distinct groups in the target population but no significant association between color pattern and genetic structure. Additionally, there was no significant association between color pattern and ontogeny or defensive behavior in these organisms. The present paper suggests that general assumptions on the biological and evolutionary role of color in opisthobranchs need to be carefully evaluated. (+info)
Insights into foraminiferal influences on microfabrics of microbialites at Highborne Cay, Bahamas.
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