An Induced Bactericidin in the Spiny Lobster, Panulirus argus

Abstract

antibodies only one segregant was found. This was susceptible to chloramphenicol and streptomycin but was resistant to tetracycline and kanamycin.Discussion. It is impossible to give a precise rate for the transfer of the R factor but clearly it was able to spread epidemically and, eventually, infect a high proportion of K12. This occurred without the selective pressure of antibiotic treatment. However, the rate of spread was much slower than in vitro. Eighteen hours after feeding AK to the mice, only O.OOS./, of K12 had acquired antibiotic resistance. In zlitro 1 . 6 v acquired drug resistance in 18 hours. Only after more than 2 weeks did more than 1C/o of the K12 in the gut acquire the R factor. Nonetheless, the rate of acquisition of the R factor was much higher than the rate of segregation.I t is uncertain to what extent we may extrapolate these findings to conventional animals. There are many differences between germ-free and conventional animals. We cannot be certain that observation in mice contaminated only with Enterobacteriacae would be similar in conventional mice who are contaminated with many species of bacteria. For example, the bacterial density of Enterobactcriacae a t the sites in the gut where the milieu is suitable for R factor transfer may be much different in mono-contaminated germfree mice and in conventional animals. Also, subtle differences in the physical and chemical makeup of intestinal contents could profoundly affect the efficiency of R factor transfer. In vitro, R factor transfer is greatly inhibited by anaerobic growth and by inhibitors of oxidative phosphorylation (6). If the intestinal contents of mono-contaminated germ-free mice were less anaerobic than the gut contents of conventional mice, the rate of transfer of the R factor would, in all probability, be greater. Further work is required to explore these factors.Summary. An antibiotic resistant Klcbsiclla pneumoniae containing an R factor was fed to germ-free mice previously colonized with an antibiotic susceptible E . coli. Within a month, 21% of the E. coli acquired multiple drug resistance without the selective pressure of antibiotic therapy. However, the rate of spread of the R factor was significantly slower than in vitro.LVe thank Miss Dorinne Kan for her able assistance.

Specificity and some physicochemical characteristics of the antibacterial activity from blue crabCallinectes sapidus

“…Relatively few studies have described such activity in marine invertebrates. Other crustaceans where antibacterial activity has been reported include the tiger shrimp Penaeus monodon (Adams, 1991), the spiny lobster Panulirus argus (Evans et al, 1968), and the stomopode Squilla martis (Danielli et al, 1989). Potent antibacterial activity has also been identified in white shrimp (Penaeus setiferus) (Noga et al, in press).…”

ECHINODERM IMMUNOLOGY: BACTERIAL CLEARANCE BY THE SEA URCHIN STRONGYLOCENTROTUS PURPURATUS

“…Secondary responses to bacteria have been elevated in other phyla, including both deuterostomes(e.g., vertebrates)and protostomes, in which molluscs(see Bayne et a!., 1980 for review;Bayne, 1980;van der Knapp, 1980), sipunculids , crustaceans (Evans et al, 1968;Acton et al, 1969;McKay and Jenkin, 1969;Stewart and Zwicker, 1974) and insects (Boman et a!., 1972; Boman et al, 1974) have yielded positive results. However, in the invertebrate examples, either enhancement has been non-specific or the extent of specificity has not been thor oughly tested, and mechanisms of enhancement are seldom known.…”

Haemolymph protein composition and copper levels in decapod crustaceans

“…Cantacuzene (1925) first identiffed these substances in the blood of hermit crabs. Panulirus argus imrnunised with a bacterial species endogenous to the lobster intestine, produce a non-dialysable bactericidin detectable in the haemolymph in less than 24 h (Evans et al, 1968). Hildemann (1974) refers to two agglutinins in the haemolymph of Homarus americanus.…”