Crystalline Cholera Toxin and Toxoid

Finkelstein, Richard A.; LoSpalluto, Joseph

doi:10.1126/science.175.4021.529

Cited by 58 publications

(34 citation statements)

References 11 publications

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“…Cholera toxin (molecular weight = 84,000), purified by the method of Finkelstein and LoSpalluto (16) was provided by the SEATO Cholera Research Program and was prepared under contract for the National Institute of Allergy and Infectious Diseases by Dr. R. A. Finkelstein, the University of Texas Southwestern Medical School, Dallas, Texas. Purified choleragenoid (molecular weight = 56,000), prepared by the procedure described by Finkelstein and LoSpalluto (16) Fresh turkey erythrocytes suspended in a modified (1) Krebs-Ringer-bicarbonate solution (KRB) were incubated with toxin for 10 min in the cold (0.1-0.25 ml of packed cells per 1.0 ml of KRB containing 10-to 10-10 M toxin), then washed twice with KRB and incubated with shaking for 3-4 hr at 38°in KRB containing 40 mM D-glucose and 0.2% bovine-serum albumin (standard medium).…”

Section: Methodsmentioning

confidence: 99%

Mode of Action of Cholera Toxin: Stabilization of Catecholamine-Sensitive Adenylate Cyclase in Turkey Erythrocytes

Field

1974

Proc. Natl. Acad. Sci. U.S.A.

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Preincubating turkey erythrocytes with cholera toxin alters their adenylate cyclase (EC 4.6.1.1) system: basal activity, maximal epinephrine-stimulatable activity, and affinity of the enzyme reaction for epinephrine are all increased. Pretreatment of erythrocytes with choleragenoid prevents these changes. Cholera toxin does not alter [PHlepinephrine uptake by intact erythrocytes. The increase in epinephrine-stimulatable cyclase activity appears to occur at the expense of fluoridestimulatable activity, which is decreased by the toxin. In lysates from both toxin-treated and control cells, maximally stimulating amounts of epinephrine and fluoride, when added in combination, have a nearly additive effect on cyclase activity. These observations suggest that the adenylate cyclase system of the turkey erythrocyte may exist in two interconvertible forms, one that is catecholamine-responsive but fluoride-insensitive, and another that is fluoride-sensitive but not coupled to catecholamine receptors. Cholera toxin appears to stabilize the enzyme in its hormone receptor-coupled form.

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Section: Methodsmentioning

confidence: 99%

Mode of Action of Cholera Toxin: Stabilization of Catecholamine-Sensitive Adenylate Cyclase in Turkey Erythrocytes

Field

1974

Proc. Natl. Acad. Sci. U.S.A.

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“…Bacterial plating was done on Difco nutrient agar plates ( N A ; 8 g Dlfco niltrient broth, 5 g NaCl, 10 g Oxoid agar in 1 litre distilled water). Syncase sucrose minimal medium was prepared as described by Finkelstein & LoSpalluto (1969). Phosphate-buffered saline (PBS; pH 7.2) was routinely used for bacterial dilution (Sinha & Srivastava, 1978).…”

Section: Me T H 0 D Smentioning

confidence: 99%

Regulation of Toxin Biosynthesis by Plasmids in Vibrio cholerae

Khan¹,

Srivastava²,

Sinha³

et al. 1985

Microbiology

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2653Vibrio cholerae strain 569B Inaba harbouring P plasmid produced less toxin than the parent strain. To examine the effect of plasmid loss on toxin production, temperature-sensitive (ts) mutants of P, unable to replicate at 42 "C, were isolated. One ts plasmid was unstable at 42 "C and its loss yielded a cured strain that resumed a normal level of toxin biosynthesis characteristic of the plasmid-free parent strain. Toxin production was again suppressed in the cured strain after reacquisition of P plasmid. This suggested a role for plasmid-borne genes in the regulation of toxin biosynthesis. A mutant of strain 569B Inaba that produced mutant toxin was isolated by transfer of P and V plasmids. The mutant toxin was similar to choleragenoid because it did not give rise to symptoms of cholera but induced antitoxin immunity in rabbits.

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“…Broth cultures of bacteria were in Difco Bacto Brain Heart Infusion (BHI) at 37 g per 1 distilled water. Syncase sucrose minimal medium was prepared as described by Finkelstein & LoSpalluto (1969). The composition of the minimal medium supplemented with other nutritional requirements was described by Bhaskaran & Sinha (1971).…”

Section: Methodsmentioning

confidence: 99%