Functional morphology of mouthparts and digestive system during larval development of the cleaner shrimp Lysmata amboinensis (de Man, 1888)

Mouthpart and alimentary canal development was examined in Lysmata amboinensis larvae using scanning electron microscopy and histology. The gross morphological features of external mouthparts and internal digestive tract structures of larvae at different developmental stages indicate that ingestive and digestive capabilities are well developed from early on. With increasing age of the larvae the mouthpart appendages increased in size, the hepatopancreas in tubular density and the midgut in length. The density of setae and robustness of teeth and spines of individual structures increased. The most pronounced changes from early to late stage larvae involved formation of pores on the paragnaths and labrum, transformation of the mandibular spine‐like teeth to molar cusps, development of the filter press in the proventriculus and of infoldings in the previously straight hindgut. The results suggest that early stage L. amboinensis larvae may benefit from soft, perhaps gelatinous prey, whereas later stages are better equipped to handle larger, muscular or more fibrous foods. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.     

Disproportionation involving an organomercurial and a sulfhydryl-containing protein. Reaction between chloromercuryferrocene and bakers'-yeast cytochrome c.

Reaction between iso-1 cytochrome c from bakers' yeast and chloromercuryferrocene, FcHgCl, does not result in simple replacement of the sulfhydryl hydrogen atom in Cys 102 with the ferrocenylmercury group, FcHg. Instead, this reaction yields the protein monomer modified at Cys 102 with an HgCl+ group and the protein dimer in which the thiolate groups of Cys 102 are bridged by a mercury(II) atom. These proteins and other organometallic products are identified by chromatographic, spectroscopic, and electrochemical methods. Organomercurials of the type RHgX and biological thiols can undergo not only substitution reactions, but disproportionation reactions as well.