Kahalalide F: a bioactive depsipeptide from the sacoglossan mollusk Elysia rufescens and the green alga Bryopsis sp

1993 ◽  
Vol 115 (13) ◽  
pp. 5825-5826 ◽  
Author(s):  
Mark T. Hamann ◽  
Paul J. Scheuer
2013 ◽  
Vol 79 (22) ◽  
pp. 7073-7081 ◽  
Author(s):  
Jeanette Davis ◽  
W. Florian Fricke ◽  
Mark T. Hamann ◽  
Eduardo Esquenazi ◽  
Pieter C. Dorrestein ◽  
...  

ABSTRACTSacoglossans are characterized by the ability to sequester functional chloroplasts from their algal diet through a process called kleptoplasty, enabling them to photosynthesize. The bacterial diversity associated with sacoglossans is not well understood. In this study, we coupled traditional cultivation-based methods with 454 pyrosequencing to examine the bacterial communities of the chemically defended Hawaiian sacoglossanElysia rufescensand its secreted mucus.E. rufescenscontains a defense molecule, kahalalide F, that is possibly of bacterial origin and is of interest because of its antifungal and anticancer properties. Our results showed that there is a diverse bacterial assemblage associated withE. rufescensand its mucus, with secreted mucus harboring higher bacterial richness than entire-E. rufescenssamples. The most-abundant bacterial groups affiliated withE. rufescensand its mucus areMycoplasmaspp. andVibriospp., respectively. Our analyses revealed that theVibriospp. that were highly represented in the cultivable assemblage were also abundant in the culture-independent community. Epifluorescence microscopy and matrix-assisted laser desorption–ionization mass spectrometry (MALDI-MS) were utilized to detect the chemical defense molecule kahalalide F on a longitudinal section of the sacoglossan.


Author(s):  
L. P. Hardie ◽  
D. L. Balkwill ◽  
S. E. Stevens

Agmenellum quadruplicatum is a unicellular, non-nitrogen-fixing, marine cyanobacterium (blue-green alga). The ultrastructure of this organism, when grown in the laboratory with all necessary nutrients, has been characterized thoroughly. In contrast, little is known of its ultrastructure in the specific nutrient-limiting conditions typical of its natural habitat. Iron is one of the nutrients likely to limit this organism in such natural environments. It is also of great importance metabolically, being required for both photosynthesis and assimilation of nitrate. The purpose of this study was to assess the effects (if any) of iron limitation on the ultrastructure of A. quadruplicatum. It was part of a broader endeavor to elucidate the ultrastructure of cyanobacteria in natural systemsActively growing cells were placed in a growth medium containing 1% of its usual iron. The cultures were then sampled periodically for 10 days and prepared for thin sectioning TEM to assess the effects of iron limitation.


2006 ◽  
Vol 8 (3) ◽  
pp. 286-293
Author(s):  
Uma Maheshwari Rajendran ◽  
Elango Kathirvel ◽  
Anand Narayanaswamy

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