Bacterial formyl peptide mediated chemotaxis and extracellular acidification in shrimp haemocytes.
The bacterial formyl peptide N-formylmethionine-leucine-phenylalanine (fMLP) is a potent chemoattractant for mammalian neutrophils. In this study, we demonstrated the binding of fluorescent dye-conjugated-fMLP to haemocytes of the penaeid shrimp Penaeus penicillatus (Alcock), through the use of flow cytometry. Fluorescence microscopy with rhodamine-fMLP suggested that fMLP receptors are present only in sub-populations of the haemocytes: granulocytes and the semi-granular cells. In addition, fMLP dose-dependently mediated chemotaxis in sub-populations of haemocytes. Microphysiometry experiments demonstrated rapid extracellular acidification upon addition of fMLP, which is in agreement with the observation in neutrophils. t-BOC, the specific fMLP receptor antagonist, was able to block the binding, chemotaxis and extracellular acidification induced by the peptide. The ability of shrimp haemocytes to migrate toward fMLP in vitro suggests that this mechanism may be important for the accumulation of these cells in infected tissues of the shrimps.
Yip
E C
EC
Biology Department, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Wong
Y H
YH
Wong
J T
JT
D000818:Animals; D002633:Chemotaxis / Q000187:drug effects*; D033364:Decapoda / Q000276:immunology*; D005110:Extracellular Space / Q000737:chemistry; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000032:analysis; D006098:Granulocytes / Q000187:drug effects / Q000502:physiology; D006434:Hemocytes / Q000145:classification / Q000187:drug effects* / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008856:Microscopy, Fluorescence; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000378:metabolism; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000502:physiology; D018000:Receptors, Peptide / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000502:physiology; D012235:Rhodamines / Q000032:analysis
D005456:Fluorescent Dyes; D009842:Oligopeptides; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D018000:Receptors, Peptide; D012235:Rhodamines; D009240:N-Formylmethionine Leucyl-Phenylalanine; C046832:t-butyloxycarbonyl-methionyl-leucyl-phenylalanine; D006180:Proton-Translocating ATPases