Identification and management of ocular lipid deposition in association with hyperlipidaemia in captive moray eels, Gymnothorax funebris Ranzani, Gymnothorax moringa (Cuvier) and Muraena retifera Goode and Bean.

Ocular lipid deposition and its surgical management and possible association with systemic hyperlipidaemia in captive moray eels are described. Ophthalmologic examinations, haematology and plasma biochemistry analyses were performed on an initial population of captive moray eels (n=10): green moray, Gymnothorax funebris Ranzani; spotted moray, Gymnothorax morninga (Cuvier) and reticulated moray, Muraena retifera Goode and Bean. Recently captured green moray eels comprised the control group (n=9). Clinical signs compatible with ocular lipid deposition were identified in six of ten captive eels (60%) vs. none of the controls. Green moray eels in the initial captive population (n=5) had significantly higher total protein, triglyceride, cholesterol and aspartate amino transferase values than the control eels. Dietary management was attempted in all captive eels, and surgical intervention was performed in three eels, including two from a separate population, with improved ocular clarity within 1month post-operatively. Histopathological evaluation of surgical specimens and two eyes from an additional affected eel that died suggested ocular lipid deposition. Eels in captivity have an apparent predisposition for hyperlipidaemia and ocular lipid deposition. Although limited in this study and complicated by exhibit restraints, dietary management was minimally effective, while surgery improved ocular clarity.

Robustness of a gene regulatory circuit.

Complex interacting systems exhibit system behavior that is often not predictable from the properties of the component parts. We have tested a particular system property, that of robustness. The behavior of a system is termed robust if that behavior is qualitatively normal in the face of substantial changes to the system components. Here we test whether the behavior of the phage lambda gene regulatory circuitry is robust. This circuitry can exist in two alternative patterns of gene expression, and can switch from one regulatory state to the other. These states are stabilized by the action at the O(R) region of two regulatory proteins, CI and Cro, which bind with differential affinities to the O(R)1 and O(R)3 sites, such that each represses the synthesis of the other one. In this work, this pattern of binding was altered by making three mutant phages in which O(R)1 and O(R)3 were identical. These variants had the same qualitative in vivo patterns of gene expression as wild type. We conclude that the behavior of the lambda circuitry is highly robust. Based on these and other results, we propose a two-step pathway, in which robustness plays a key role, for evolution of complex regulatory circuitry.

Microinjection of calpastatin inhibits fusion in myoblasts.

Rat satellite cells (RSC) were microinjected with purified calpastatin or m-calpain, and myoblasts from a C2C12 mouse line were microinjected with purified calpastatin. Microinjection with calpastatin completely prevented fusion of myoblasts from both sources, whereas microinjection with m-calpain significantly increased the rate of fusion of cultured RSC; 44% of the nuclei of RSC cultures were in multinucleated myotubes within 48 h after microinjection with m-calpain plus labeled dextran, whereas only 15% of the nuclei were in multinucleated myotubes after microinjection with dextran alone. Western analyses indicated that neither RSC nor C2C12 myoblasts contained detectable amounts of mu-calpain before fusion. The levels of calpastatin in C2C12 myoblasts increased as cells passed from the proliferative stage to the onset of fusion, and these levels increased substantially in both the C2C12 and the RSC cells as they progressed to the late or postfusion stage. Both RSC and C2C12 myoblasts contained an 80-kDa polypeptide that was labeled with an anti-m-calpain antibody in Western blots. The results are consistent with a role of the calpain system (m-calpain in these myoblast lines) in remodeling of the cytoskeletal/plasma membrane interactions during cell fusion.