Biochim Biophys Acta, 1981 Jun 9, 644(1), 143 - 6 Cholera toxin induces changes in the ion permeability of intestinal brush border membranes; Bavros F et al.; Cholera toxin can alter the ion permeability of brush border membrane vesicles from rabbit small intestine . This alteration is reflected by differences in membrane potential-stimulated, Na-dependent, D-{3H}glucose transport by these vesicles, as well as by an enhancement in the accumulation of the lipophilic cation {3H}tetraphenylphosphonium in response to an artificially imposed membrane potential . Analogous effects were observed when the intact tissue was treated with the toxin and the vesicles subsequently obtained . An important implication of this finding is that cholera toxin does not need to activate adenylate cyclase to induce permeability changes in the cell membrane since the experiments were carried out in conditions where neither ATP nor cyclic AMP was present. Antibiotiki, 1981 May, 26(5), 379 - 83 {Energy allowance for antibody formation in rabbits immunized with cholera vaccine and by exposure to tetracyclines}; Tsyganenko AIa et al.; Oxidative phosphorylation and succinate dehydrogenase activity in liver mitochondria, as well as activity of glucoso-6-phosphate dehydrogenase in liver homogenates were studied on 126 rabbits immunized with cholera vaccine and exposed to tetracycline or doxycycline (vibramycin) . It was found that tetracycline and especially doxycycline inhibited the bioenergy processes in both intact and immunized animals . The inhibitory effect of doxycycline was most pronounced in the immunized rabbits . The shifts in the titers of the specific antibodies under the experimental conditions directly correlated with the state of the endocellular oxidation-reduction processes. Biochim Biophys Acta, 1981 Apr 3, 673(4), 477 - 86 Endogenous and cholera toxin-catalyzed ADP-ribosylation of a plasma membrane protein by RL-PR-C cloned rat hepatocytes; Beckner SK et al.; Cholera toxin catalyzed the ADP-ribosylation of a single plasma membrane protein (Mr 55 000) of both RL-PR-C rat hepatocytes and purified rat liver plasma membranes . Labeling of this protein from nicotinamide {2,8-3H}adenine dinucleotide was competitively inhibited by free arginine, but by no other amino acid tested, including lysine . The same protein was ADP-ribosylated from NAD+ endogenously, i.e., in the absence of toxin . This process was, however, not competitively inhibited by added arginine nor by any other amino acid tested lysine . Free ADP-ribose, even in 50-fold molar excess over the nicotinamide {2,8-3H}adenine dinucleotide substrate, did not reduce (by isotope dilution) the endogenous or cholera toxin-catalyzed labeling of the 55 000 dalton membrane protein . It is likely, therefore, that hepatocyte plasma membranes contain an ADP-ribosyltransferase, with a mechanism similar to that of the A subunit of cholera toxin, in that both transfer ADP-ribose to the same membrane protein and in that neither apparently produce free ADP-ribose as an intermediate . It is also clear that the acceptor residue in the 55 000 dalton protein is different for each process . Cholera toxin-catalyzed and endogenous transfer of ADP-ribose to the hepatocyte plasma membrane protein, in contrast to a pigeon erythrocyte system, required no cytosolic factors . The results indicate that ADP-ribosylation in cloned differentiated rat hepatocytes differs from that in pigeon erythrocytes in that the acceptor protein is larger (55 000 compared to 42 000 daltons), cytosolic factors are not required and transfer of ADP-ribose to the acceptor protein occurs endogenously. Int J Epidemiol, 1981 Mar, 10(1), 23 - 5 The relationship of cholera to water source and use in rural Bangladesh; Khan MU et al.; The cholera experience of a sample of families in a rural area of Bangladesh is reported in relation to water supply and use . Tanks were the primary source for 65% of families, canals for 20% and the river for 14% . The highest attack rate was associated with access to canal water (13%) . Attack rates did not vary markedly according to the purpose for which a source was used . The importance of cultural patterns in water use is identified. J Exp Med, 1981 Mar 1, 153(3), 534 - 44 Special features of the priming process for a secretory IgA response . B cell priming with cholera toxin; Fuhrman JA et al.; Administration of cholera toxin/toxoid by either intraduodenal or parenteral routes increases the frequency of antigen-sensitive B cells in Peyer's patches (PP) and in distant lymphoid tissues greater than 50-fold . The special feature of mucosal priming with toxin is its unique effectiveness at generating secondary B cells, whose progeny express IgA exclusively, and such cells appear in highest frequency in PP and in appreciable numbers in spleen . Thus, this deliberate intraduodenal immunization seems to mimic the natural priming process induced by enteric bacterial colonization, which we have postulated to account for the high frequencies of IgA-committed cells specific for bacterial determinants in the PP of conventionally reared mice . furthermore, as a result of intraduodenal immunization, antigen-specific memory B cells are disseminated to sites distant form that of antigen application, including the lymphoid follicles associated with the respiratory mucosa . Direct antigenic stimulation of cells in the PP therefore results in effective cross-priming among mucosal and systemic sites through division, differentiation, and disemination of antigen-sensitive secondary B cells. Invest Ophthalmol Vis Sci, 1981 Mar, 20(3), 410 - 4 Effects of intravitreal cholera toxin on adenosine 3',5'-monophosphate, intraocular pressure, and outflow facility in rabbits; Bartels SP et al.; Catecholamines, prostaglandins, and various hormones may influence aqueous humor dynamics via the second messenger, adenosine 3',5'-monophosphate (cyclic AMP) . To test this hypothesis in rabbit ocular tissues, we have investigated the effects of cholera toxin (CTX), a specific, irreversible activator of adenylate cyclase . CTX (5 x 10(-4) to 5 x 10(2) microgram/ml) in both the presence and absence of isobutylmethylxanthine (IBMX) increased cyclic AMP production in the isolated iris-ciliary body . The effects of CTX were dependent on its concentration, duration of exposure, and presence of IBMX . Furthermore, iris-ciliary bodies and scleral-trabecular rings exercised after intravitreal injection of 10 microgram of CTX and incubated in vitro produced significantly more cyclic AMP than contralateral control tissues . Thus significant binding of CTX to both iris-ciliary body and scleral-trabecular ring occurred within 5 hr after intravitreal injection . Intraocular pressure (IOP) and outflow facility were measured by intraocular cannulation . Five hours after intravitreal injection of CTX, the IOP was lower than in control eyes . At this time, the outflow facility was threefold greater in the CTX-treated eyes than in control eyes . On the basis of these results, we conclude that (1) CTX stimulates cyclic AMP production in iris-ciliary body and scleral-trabecular ring of rabbits, (2) IOP decreases and outflow facility increases after intravitreal injection of CTX, and (3) the hypotensive effect of CTX is apparently mediated, at least partially, by outflow mechanisms. Invest Ophthalmol Vis Sci, 1981 Mar, 20(3), 371 - 81 Intraocular pressure and aqueous flow are decreased by cholera toxin; Gregory D et al.; Delivery of 2.1 microgram of cholera toxin, a specific, irreversible activator of adenylate cyclase, via the blood lowers IOP from 17.4 to 11.2 mm Hg in 81/2 hr . decreases net aqueous flow by about 50% in 8 hr, and doubles blood flow to the anterior uvea at 8 to 13 hr . Intravitreal injection of 0.26 microgram of cholera toxin lowered IOP from 15.0 to 9.6 mm Hg, but heat-inactivated toxin had no effect on IOP . The toxin activates adenylate cyclase from ciliary processes 2.2-fold and stimulates cyclic AMP production by ciliary processes 7.4 times . Absence of aqueous flare, normal protein concentrations in the aqueous, and histologic examination all confirmed the functional and structural integrity of the blood-aqueous barrier after cholera toxin infusion . The data point to an important role for ciliary process adenylate cyclase in regulation of aqueous flow and maintenance of IOP. Biochim Biophys Acta, 1981 Feb 18, 673(1), 114 - 23 Role of guanine nucleotides in the stimulation of thyroid adenylate cyclase by prostaglandin E1 and cholera toxin; Friedman Y et al.; Cholera toxin in the presence of GTP increased adenylate cyclase activity in a purified bovine thyroid plasma membrane preparation, whereas, in the presence of guanosine 5'-(beta, gamma-imido)-triphosphate (Gpp(NH)P), cholera toxin had no stimulatory effect . Similarly, prostaglandin E1 enhanced the adenylate cyclase activity induced by GTP but not by Gpp(NH)p . Gpp(NH)p-stimulated adenylate cyclase activity, assayed with hydrolysis-resistant adenosine 5'-(beta, gamma-imido)-{32P}triphosphate as substrate and no ATP-regenerating system was inhibited by GDP in a competitive fashion . Furthermore, prostaglandin E1, but not cholera toxin, influenced the GDP inhibition of Gpp(NH)p-stimulated activity by increasing the concentration of GDP resulting in 50% inhibition approx . 2-fold . Inosyl nucleotides mimicked the effects of guanyl nucleotides on thyroid adenylate cyclase in that ITP could substitute for GTP in enhancing cholera toxin- and prostaglandin #1-induced activities and that inosine 5'(beta, gamma-imido)-triphosphate {Ipp(NH)p} was also a potent stimulator per se . Conclusions . (1) Cholera Toxin and prostaglandin E1 enhance thyroid adenylate cyclase activation by GTP (or ITP), but have no stimulatory effect on the Gpp(NH)p (or Ipp(NH)p) response; (2) the stimulatory effect of prostaglandin E1 on adenylate cyclase may result from decreased affinity for GDP at the guanine nucleotide regulatory site; (3) the date regarding cholera toxin stimulation of thyroid adenylate cyclase are consistent with the hypothesis that cholera toxin exerts its effect by inhibiting an endogenous GTPase. J Biol Chem, 1981 Feb 10, 256(3), 1094 - 7 Observation by 13C NMR of interactions between cholera toxin and the oligosaccharide of ganglioside GM1; Sillerud LO et al.; The initial event in the action of cholera toxin on intact cells is its recognition of cell-surface receptors, molecules of ganglioside GM1 . We have studied details of this interaction by 13C NMR, which enables us to examine simultaneously both the protein and the ganglioside or, as in the present instance, its oligosaccharide portion . 13C NMR spectra of the toxin are consistent with the long correlation times expected for this 84,000-dalton protein . They show, however, some resolved resonances (including one tentatively assigned to the epsilon 2 carbon of tryptophan, 138.3 ppm downfield from tetramethylsilane) . When oligosaccharide is added to the toxin this resonance broadens or moves further upfield to reside under phenylalanine resonances at 136.7 ppm . Of the seven tryptophan residues in cholera toxin, five are in the B subunits which bind GM1, so that the data are consistent with a resonance shift for the epsilon 2 carbons of these residues on binding the oligosaccharide . Resonances arising from the anomeric and methylene carbons of the sialic acid moiety of the oligosaccharide are also shifted . Comparison with corresponding chemical shifts in a series of model compounds suggest that the latter effects may originate in a toxin-induced conformational change in the oligosaccharide . At high resolution, anomeric carbon resonances of terminal galactose residues in free and bound oligosaccharide are also resolved. Biochim Biophys Acta, 1981 Feb 5, 672(3), 248 - 61 Activation of pigeon erythrocyte adenylate cyclase by cholera toxin . Partial purification of an essential macromolecular factor from horse erythrocyte cytosol; Le Vine H 3rd et al.; A cytosolic, macromolecular factor required for the cholera toxin-dependent activation of pigeon erythrocyte adenylate cyclase and cholera toxin-dependent ADP-ribosylation of a membrane-bound 43,000 dalton polypeptide has been purified 1100-fold from horse erythrocyte cytosol using organic solvent precipitation and heat treatment . This factor, 13,000 daltons, does not absorb to anionic or cationic exchange resins, is sensitive to trypsin or 10% trichloroacetic acid and is not extractable by diethyl ether . Activation of adenylate cyclase by cholera toxin requires the simultaneous presence of ATP (including possible trace GTP), NAD+, dithiothreitol, cholera toxin, membranes and the cytosolic macromolecular factor . Reversal of cholera toxin activation of adenylate cyclase, and of the toxin-dependent ADP-ribosylation, requires the presence of the cytosolic factor . The ability of the purified cytosolic factor to influence the hormonal sensitivity of liver membrane adenylate cyclase may provide clues to its physiological functions. J Neurochem, 1981 Feb, 36(2), 580 - 8 Opioids, noradrenaline and GTP analogs inhibit cholera toxin activated adenylate cyclase in neuroblastoma x glioma hybrid cells; Propst F et al.; D-Ala2-Met5-enkephalin, morphine, and noradrenaline inhibit the adenylate cyclase in homogenates of neuroblastoma x glioma hybrid cells in a dose-dependent manner even after the enzyme has been preactivated by cholera toxin . Half-maximal inhibition and extent of inhibition are the same with native or cholera toxin-activated enzyme . The inhibition caused by opioids or noradrenaline are antagonized by naloxone or phentolamine, respectively . The effect of D-Ala2-Met5-enkephalin on cholera toxin-activated enzyme is immediate in onset and rapidly reversed by the addition of naloxone . Guanyl-5'-yl-imidodiphosphate stimulates basal activity but inhibits the enzyme activated by cholera toxin or prostaglandin E1 . Stimulation occurs at a concentration of 100 microM or above, inhibition even at 0.1 microM . The inhibitory effect of the non-hydrolysable GTP analog is antagonized by GTP . Guanyl-5'-yl-methylenediphosphonate, another nonhydrolysable GTP analog, inhibits basal as well as cholera toxin-stimulated or prostaglandin E1-stimulated adenylate cyclase . Other guanine derivatives such as GDP, GMP, cyclic GMP, guanyl-5'-yl-phosphoric acid amide and guanosine have no effect under the same conditions . The results may be taken as a piece of evidence for two separate guanyl nucleotide-binding sites accompanying the adenylate cyclase in the hybrid cells and mediating, respectively, stimulation and inhibition of the enzyme by hormones. J Neurochem, 1981 Feb, 36(2), 538 - 43 Polypeptide hormones and chromatin-associated proteins act as acceptors for cholera toxin-catalyzed ADP-ribosylation; Trepel JB et al.; Cholera toxin catalyzed the ADP-ribosylation of the pituitary protein hormones thyrotropin (TSH), lutropin (LH), follitropin (FSH), human chorionic gonadotropin (hCG), and corticotropin (ACTH)1-24, and ADP-ribosylation of the basic proteins histone subfraction H1 and protamine . Casein and phosvitin, acidic nuclear proteins, did not act as acceptors for toxin-catalyzed ADP-ribosylation . The isolated TSH A and B subunits were tested for their ADP-ribose acceptor activity . The TSH A subunit showed fourfold greater ADP-ribose acceptor activity than the TSH B subunit . The ADP-ribose acceptor protein protamine was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis following incubation with cholera toxin under ADP-ribosylating conditions . {3H}ADP-ribose incorporated into protein from {3H}NAD migrated with the acceptor protein protamine . In the absence of added acceptor protein, the {3H}ADP-ribose incorporated into protein migrated with the A1 fragment of cholera toxin . Cholera toxin A and B subunits were isolated and tested for their ability to catalyze the transfer of ADP-ribose to protamine . The cholera toxin A subunit showed 50-fold greater ADP-ribosyltransferase activity than the B subunit . Our data indicate that a variety of adenohypophyseal hormones and regulatory proteins act as acceptors for toxin-catalyzed ADP-ribosylation . These studies may help in understanding the role of endogenous ADP-ribosyltransferases and the physiological effects of this modification of protein. Endocrinology, 1981 Feb, 108(2), 632 - 8 The dynamics of the steroidogenic response of perifused Leydig tumor cells to human chorionic gonadotropin, ovine luteinizing hormone, cholera toxin, and adenosine 3',5'-cyclic monophosphate; Segaloff DL et al.; A perifusion system has been developed in which a dose-dependent response of isolated Leydig tumor cells to steroidogenic stimuli, as assessed by the rates of steroid production, can be measured as a function of time . In response to a continuous perifusion for 340 min with a saturating concentration of hCG, ovine LH (oLH), cholera toxin, or 8-Br-cAMP, there is a rapid increase in the rate of progesterone production, which reaches a maximum about 100 min after the onset of stimulus in the medium and then declines to a rate somewhat higher than basal . Thus cholera toxin and 8-Br-cAMP as well as hCG and oLH are able to desensitize the Leydig tumor cells to further stimulation by the same agent . Although a 10-min pulse of a saturating concentration of hCG yields the same steroidogenic response as that elicited by continuous perifusion with saturating hCG, a pulse of a saturating concentration of oLH yields a steroidogenic response only when oLH is maintained in the perifusate . These data establish a substantial difference in the actions of hCG and oLH . The results could be explained by the higher apparent affinity of hCG for the gonadotropin receptor, such that, upon removal of hormone from the perifusate, oLH would be more readily eluted from the receptor . These findings support the hypothesis that oLH and hCG exert their stimulatory effects only while bound to the cell surface . (Endocrinology 108: 632, 1981) Nature, 1981 Jan 22, 289(5795), 319 - 21 Photolabelling of cholera toxin subunits during membrane penetration; Wisnieski BJ et al.; There has been much speculation about the mechanism by which cholera toxin exerts its effect on the cytoplasmic side of the membranes with which it interacts . After the pentamer of B subunits (5B) binds to membrane receptors, particularly the monosialylganglioside GM1, the disulphide-linked dimer A1SSA2 (which together with 5B constitutes the complete toxin) is thought to penetrate the membrane, perhaps through a channel formed by 5B and become reduced so that A1SH units reach the cytoplasm and stimulate adenylate cyclase . Evidence for this mechanism is circumstantial . If it is correct, a compound which will specifically label intramembranous sections of the toxin should label the channel-forming B subunits but not the channel-contained A1 subunit . We have tested this prediction with a photoreactive glycolipid compound and have obtained the opposite result . Therefore, we propose that only the A1 subunit enters the membrane and we provide here data on the kinetics of that process. Int J Cancer, 1981 Jan 15, 27(1), 29 - 36 Inhibitory effect of cholera toxin on human natural cell-mediated cytotoxicity and its augmentation by interferon; Fuse A et al.; Cholera toxin inhibits human natural cell-mediated cytotoxicity in a dose- and time-dependent manner . Pretreatment of lymphocytes with 10 ng/ml of cholera toxin for 2 h almost completely inhibited cytolysis . Interferon augmented human natural cell-mediated cytolysis, but when lymphocytes were pretreated with cholera toxin before interferon treatment, no enhancement of cytolysis occurred . Cholera toxin could inhibit the enhancement of cytolysis by interferon even when lymphocytes were treated with cholera toxin after 2 h interferon treatment . Cholera toxin subunit B which binds cell surface ganglioside galactosyl-N-acetylgalactosaminyl - {N-acetylneuraminyl} - galactosylglucosylceramide (GM1) without activating adenyl cyclase had no effect either on natural cytolysis or on the enhancement of natural cytolysis by interferon, suggesting that mere binding of cholera toxin to the cellular receptor was not enough to inhibit natural cell-mediated cytolysis . Cyclic adenosine 3',5'-monophosphate (cAMP) levels increased in cholera toxin-treated lymphocytes and the time course of cAMP accumulation was similar to that of cytotoxicity inhibition . Exogenous dibutyryl-cAMP (db-cAMP) and theophylline inhibited cytolysis, while exogenous dibutyryl cyclic guanosine 3',5'-phosphate (db-cGMP) enhanced cytolysis slightly, suggesting that the process of inhibition of human natural cell-mediated cytolysis was at least partly modulated by intracellular cyclic nucleotides. Am J Physiol, 1981 Jan, 240(1), G10 - 6 Cholera toxin stimulates secretion of immunoreactive intestinal mucin; Forstner JF et al.; In vitro secretion of goblet cell mucin from rat small intestine was measured using a double-antibody radioimmunoassay for mucin . Cholera toxin (12.5-50 mg crude filtrate/ml) added to incubations of intestinal slices caused a dose-dependent increase in mucin secretion . By 90 min there was a four- to fivefold enhancement in secretion over noncholera-treated controls . Crude filtrate (dialyzed or nondialyzed) was a more effective mucin secretogogue than purified enterotoxin . Secretion was also assessed by administering {1-14C}glucosamine intraperitoneally to rats in vivo and 3 h later monitoring in vitro secretion of radioactive glycoprotein from intestinal slices . Cholera filtrate (12.5-50 mg/ml) caused a 1.5- to 2.0-fold enhancement in secretion after 90 min . The radioactivity data, however, underestimated total mucin secretion and the dependency of secretion on the dose of cholera filtrate . Cholera preparations also caused an enhancement (20-30% over controls) in the incorporation of {3H}glucosamine into tissue acid-precipitable glycoprotein, indicating a stimulation of glycoprotein synthesis . In the same experiments it was noted that the secretion of 3H-labeled (i.e., newly glycosylated) glycoprotein was increased 2.5- to 3.0-fold over untreated controls . Assuming that radioactivity partially reflects mucin synthetic and secretory events, it is possible, therefore, that cholera toxin promotes the release of both "old" mucin from storage granules as well as the synthesis and secretion of "new" mucin formed in goblet cells during incubation. Am J Vet Res, 1981 Jan, 42(1), 135 - 7 Congenital tremor in pigs farrowed from sows given hog cholera virus during pregnancy; Vannier P et al.; At different stages of gestation, 3 groups of pregnant sows were inoculated with a strain of hog cholera virus (HCV) . After the infection, clinical signs of hog cholera were not observed in the sows . Pigs from the sows infected on day 22 or 43 of gestation showed varying degrees of muscular tremor, ataxia, splayleg, and suckling inability . Of the pigs with tremor, 83% had cerebellar hypoplasia . Surviving pigs demonstrated persistent viral infection and continued to shed HCV, but did not have antibodies to HCV . Sows infected at 72 days of gestation farrowed numerous mummified and stillborn pigs . Signs of tremor were not seen in any pigs from these sows. Natl Inst Anim Health Q (Tokyo), 1981 Winter, 21(4), 153 - 8 Micro method for performing titration and neutralization test of hog cholera virus using established porcine kidney cell strain; Komaniwa H et al.; Hog cholera (HC) virus and antibody against it were estimated by the END method with microplates and CPK porcine kidney cell strain . To establish the technique of this method, studies were made on such basic conditions of the method as the type of strain of Newcastle disease virus (NDV), the time of challenge with this virus, and the concentration of serum in culture fluid . There was little difference in the infective titer of HC virus estimated between the END method performed by the established technique and the same method by the conventional technique with test tubes and swine testicle (ST) cells . Besides, there was a high correlation between the neutralizing antibody titer measured by the one technique and that measured by the other . The coefficient of correlation was r = +0.948 in this case . From the experimental results mentioned above it was concluded that the END method by the micro-technique with CPK cells was simpler than and as reliable as the same method conducted by any conventional technique, and that it was a practicable one capable of testing many samples. Int Arch Allergy Appl Immunol, 1981, 64(2), 217 - 21 Decrease in cholera toxin-binding T cells in aged mice and human volunteers; Tsuru S et al.; The capacity of T cell-enriched populations of cells from mice and human volunteers to bind cholera toxin was analyzed by means of a fluorescence-activated cell sorter . In aged mice and humans, the number of cells capable of binding high concentrations of cholera toxin was lower than that in young mice and humans . The capacity to bind cholera toxin may be one of the useful indicators for the detection of aging in the immune system. J Cyclic Nucleotide Res, 1981, 7(4), 247 - 57 A new principle for resistance to cholera: desensitization to cyclic AMP-mediated diarrhea induced by cholera toxin in the mouse intestine; Lonnroth I et al.; The mechanisms behind the intestinal resistance to cholera toxin was studied in a mouse model . Repeated peroral treatments with cholera toxin (CT) led to a long-lasting inhibition of the toxin-induced activation of intestinal adenylate cyclase (AC) . A corresponding inhibition of the intestinal fluid secretion induced not only by CT but also by prostaglandin E1 was observed . This unspecific desensitization was followed by a CT-specific inhibition of secretion and AC after 8 to 16 days . The desensitization to CT was totally reversed by a 4 hour-treatment with cycloheximide, an inhibitor of protein synthesis . Neither the secretory response to dibutyryl-cyclic AMP nor the activity of soluble phosphodiesterase differed between the CT-treated mice and the control group . Nor was the average turn-over rate of intestinal cells changed as judged from the mucosal incorporation of {3H}-thymidine . It is postulated that intestinal resistance to CT is mainly a function of AC-desensitization mediated by an inducible protein. Bull Soc Pathol Exot Filiales, 1981 Jan-Feb, 74(1), 17 - 30 {Epidemiology of cholera in the world . Development between 1970 and 1980}; Felix H et al.; The authors present a general review of ten year evolution of the 7th pandemic of cholerae . They discuss the official data known from the country declarations . From the epidemiological features they distinguish a hydric dilution model of cholerae (few cases, few carriers, endemicity) and a direct inter-human contamination type (epidemic outbreaks, no endemicity). J Cyclic Nucleotide Res, 1981, 7(6), 363 - 74 Differential effects of cholera toxin on guanine nucleotide regulation of beta-adrenergic agonist high affinity binding and adenylate cyclase activation in frog erythrocyte membranes; Stadel JM et al.; The guanine nucleotide regulatory protein(s) regulates both adenylate cyclase activity and the affinity of adenylate cyclase-coupled receptors for hormones or agonist drugs . Cholera toxin catalyzes the covalent modification of the nucleotide regulatory protein of adenylate cyclase systems . Incubation of frog erythrocyte membranes with cholera toxin and NAD+ did not substantially alter the dose dependency for guanine nucleotide activation of adenylate cyclase activity . In contrast, toxin treated membranes demonstrated a 10 fold increase in the concentrations of guanine nucleotide required for a half maximal effect in regulating beta-adrenergic receptor affinity for the agonist (+/-) {3H}hydroxybenzylisoproterenol . The data emphasize the bifunctional nature of the guanine nucleotide regulatory protein and suggest that distinct structural domains of the guanine nucleotide regulatory protein may mediate the distinct regulatory effects on adenylate cyclase and receptor affinity for agonists. Biochim Biophys Acta, 1980 Dec 16, 626(2), 443 - 50 A hybrid toxin containing fragment A from diphtheria toxin linked to the B protomer of cholera toxin; Mannhalter JW et al.; We have constructed and characterized a hybrid toxin containing the A chain of diphtheria toxin linked via a disulfide bridge to the B protomer of cholera toxin . Cholera toxin B protomer, previously derivatized with 4-5 cystaminyl groups per pentameric protomer, was reacted with reduced diphtheria toxin chain A to give the desired hybrid, containing an average of 2 molecules of diphtheria toxin chain A per cholera toxin B protomer . A concentration of 0.3 nM hybrid inhibited protein synthesis by 50% in 24 h in several cultured cell lines; thus the hybrid was about 10-fold more toxic than of a (diphtheria toxin chain A)-SS-(concanavalin A) conjugate described previously . Evidence was obtained that toxicity of the hybrid was dependent on the functional contributions of both the diphtheria toxin chain A and cholera toxin B protomer moieties. Nature, 1980 Dec 4, 288(5790), 499 - 501 Amino acid sequence homology between cholera toxin and Escherichia coli heat-labile toxin; Dallas WS et al.; Cholera toxin (CT) and the Escherichia coli heat-labile toxin (LT) are functionally, structurally and immunologically similar enterotoxins . Both toxins cause the elevation of cyclic AMP levels in gut epithelial cells by catalysing the NAD-dependent ADP ribosylation of membrane proteins . Each toxin is composed of two dissimilar subunits . The A subunit has an enzymatic activity and is the adenylate cyclase-activating component of the enterotoxin . The B subunit recognizes membrane components and binds the holotoxin to the target call juxtaposing the A subunit with its substrates . Binding studies and competition experiments indicate that the membrane receptors for cholera toxin B subunit (CT-B) and LT-B are similar but not identical (these studies were performed before by LT was purified to homogeneity) . The monosialosylganglioside GMI has been shown to be the receptor for the cholera toxin, and it probably composes part of the receptor for LT . Gyles and Barnum, first reported that LT and cholera toxin were immunologically related, and it has subsequently been shown that they share common antigenic determinants in both A and B subunits . The primary structure of CT-B has been determined . We report here a comparison between the amino acid sequences of LT-B and CT-B . The nucleotide sequence of the LT-B cistron (eltB) was determined using a recombinant plasmid encoding LT . Translation of this sequence revealed that LT-B and CT-B show significant amino acid sequence homology . In addition, several features of the eltB cistron were revealed by the sequence analysis. Johns Hopkins Med J, 1980 Dec, 147(6), 209 - 11 Effect of nicotinic acid on cholera-induced fluid movement and unidirectional sodium fluxes in rabbit jejunum; Turjman N et al.; Cholera toxin produces intestinal secretion and elevation of intestinal cyclic AMP . Nicotinic acid has been shown to prevent these responses . The effect of nicotinic acid on cholera toxin-induced secretion could be caused by decreased plasma-to-lumen flux, increased lumen-to-plasma flux, or a combination of both . The purpose of this study was to define the effects of nicotinic acid on net fluid movement and unidirectional sodium fluxes in rabbit jejunal loops exposed to cholera toxin . In the untreated animals receiving no nicotinic acid, the cholera toxin-exposed loops secreted 0.91 ml/cm/4h above the control loops receiving no cholera toxin (p < 0.01) . On the other hand, pretreatment with 100 mg/kg nicotinic acid caused a striking decrease in secretion in the cholera toxin loop, so that the cholera toxin loop was not significantly different from the control loop . Unidirectional sodium fluxes in untreated animals showed that cholera toxin caused an increase in the plasma-to-lumen flux and a decrease in the lumen-to-plasma flux . Both effects were abolished by pretreating the animals with nicotinic acid . These studies indicate that nicotinic acid prevents cholera toxin-induced secretion by restoring the unidirectional fluxes to control levels. Med J Zambia, 1980 Dec-1981 Jan, 15(1), 10 - 3 Cholera control in an inaccessible district in Tanzania: importance of temporary rural centres; Mandara MP et al.; The fourth ever recorded outbreak of cholera on Tanzania mainland started on 2.10.77 in Twasalie village which is a delta island in the Utete district on the Indian Ocean coastal line . Poor communication and inadequate health facilities in the district delayed detection and reporting of the outbreak for four weeks leading to wide dissemination of the disease . Socio-cultural and religious practices by residents of the district especially the procedure of burying the dead played a key role in enhancing spread of the infection . The outbreak was controlled by establishing 16 multipurpose cholera centres in the district . Whereas 55% of the 69 patients with the disease before control measures were introduced died, the mortality rate was reduced to 1.6% out of the 184 severely ill patients admitted to treatment centres. Am J Vet Res, 1980 Dec, 41(12), 2012 - 5 Atypical hog cholera infection: viral isolation and clinical study of in utero transmission; Plateau E et al.; Sows in different stages of pregnancy were inoculated with a low-virulence hog cholera strain . Clinical signs of disease were not observed in the sows during pregnancy, but most of their pigs were splaylegged and had nervous disorders; perinatal mortality was high . A few pigs from sows that were inoculated during the 1st trimester of pregnancy survived and remained inapparent carriers of virus, without developing antibodies . Seemingly, these pigs were immunotolerant . Virus was transmitted from immunotolerant pigs to susceptible pigs by contact 5 weeks after farrowing, but not 3 months after farrowing, despite the persistence of the virus at a high concentration in the blood and in the organs of the immunotolerant pigs. Med J Zambia, 1980 Dec-1981 Jan, 15(1), 10 - 3 Cholera control in an inaccessible district in Tanzania: importance of temporary rural centres; Mandara MP et al.; The fourth ever recorded outbreak of cholera on Tanzania mainland started on 2.10.77 in Twasalie village which is a delta island in the Utete district on the Indian Ocean coastal line . Poor communication and inadequate health facilities in the district delayed detection and reporting of the outbreak for four weeks leading to wide dissemination of the disease . Socio-cultural and religious practices by residents of the district especially the procedure of burying the dead played a key role in enhancing spread of the infection . The outbreak was controlled by establishing 16 multipurpose cholera centres in the district . Whereas 55% of the 69 patients with the disease before control measures were introduced died, the mortality rate was reduced to 1.6% out of the 184 severely ill patients admitted to treatment centres. J Histochem Cytochem, 1980 Dec, 28(12), 1334 - 42 Differential expression of surface monosialoganglioside GM1 in various hemic cell lines of normal human bone marrow . A quantitative immunocytochemical study using the cholera toxin-gold-labeled anti-cholera toxin procedure; Ackerman GA et al.; The cholera toxin-colloidal gold-labeled IgG-F(ab')2 anti-cholera toxin ultrastructural immunocytochemical procedure has been used for the localization of GM1 monosialogangliosides on the surface of human bone marrow cells . The number of gold particles per micron of cell surface was counted and the data subjected to statistical analysis . Cholera toxin (CT) binding characteristics assessed in several subjects showed consistent labeling patterns for the various types of marrow cells, although minor quantitative differences were noted in surface labeling densities between subjects . Surface labeling was nonuniformly distributed along the cell membrane of the marrow cells and label clusters or domains were commonly noted . Data analysis indicated that CT labeling was related to cell type, to cell lineage, and to the stage of maturation . Mature neutrophils were the most reactive of the marrow cells and the CT labeling of this cell series increased stepwise from the promyelocyte stage to the segmented neutrophil . A similar pattern occurred during eosinophil maturation and the maturation of the monocyte . A different labeling pattern was found during the differentiation of the erythrocytic cell series with low labeling of proerythroblasts increasing modestly to the early normoblast stage and then decreasing during the final phase of maturation . Exposure to neuraminidase prior to the immunocytochemical sequence induced a major increase in surface CT labeling of the various types of marrow cells, as was particularly evident for the platelet, promyelocyte, myelocyte, monocyte, promonocyte, and erythrocyte cell groups . The data indicated that the number of cryptic GM1 and/or higher gangliosides exposed by neuraminidase in the cell membrane varied during cell differentiation and was directly related to specific cell types . Exogenous GM1 also was demonstrated to be incorporated into the surface of the bone marrow cells in a differential manner and the extent of incorporation was found to be related to specific cell types and to their stage of maturation. Biochim Biophys Acta, 1980 Dec 1, 633(2), 237 - 44 Inhibition of lipolysis and cyclic AMP accumulation by adenosine analogues in hamster epididymal adipocytes exposed to cholera toxin; Schimmel RJ et al.; The effects of adenosine, N6-phenylisopropyl adenosine and 2',5'-dideoxyadenosine on lipolysis and cyclic AMP accumulation, in hamster adipocytes treated with cholera toxin, were studied . Cholera toxin caused an increase in lipolysis and cyclic AMP accumulation that was dependent upon the concentration of toxin and the length of time cells were exposed to the toxin . When N6-phenylisopropyl adenosine or 2',5'-dideoxyadenosine were present, the lipolytic and cyclic AMP responses to cholera toxin were inhibited . The adenosine analogues were equally effective inhibitors of lipolysis and cyclic AMP accumulation, when they were added 1 or 2 h after exposure to the toxin . Enzymatic removal of endogenously produced adenosine with adenosine deaminase potentiated both the lipolytic and cyclic AMP responses to cholera toxin . In addition, the inhibitory effects of N6-phenylisopropyl adenosine, 2'5'-dideoxyadenosine and clonidine on lipolysis and cyclic AMP were enhanced consequent to enzymatic removal of adenosine . These data show responses of intact fat cells to N6-phenylisopropyl adenosine, 2',5'-dideoxyadenosine or removal of endogenous adenosine and provide evidence for an adenosine sensitivity of fat cells exposed to cholera toxin. J Invest Dermatol, 1980 Dec, 75(6), 508 - 11 Effects of cholera toxin on ornithine decarboxylase activity in mouse skin; Murray AW et al.; The subcutaneous injection of cholera toxin into adult mice resulted in a sustained increase in cyclic AMP levels in mouse epidermis after a lag period of about 2 hr . An increase in ornithine decarboxylase activity occurred between 7 and 10 hr, which was maintained for at least 10 hr . The increase in decarboxylase activity was localized to the area of epidermis visually affected by cholera toxin and was unaffected by hypophysectomy, suggesting a direct effect of the toxin on the epidermal cells . The subcutaneous injection of cholera toxin also led to an increase in cyclic AMP levels in newborn mouse skin . In contrast to adult mice, newborn mouse skin contained high basal activities of ornithine decarboxylase in both the epidermal and dermal fractions . The activity in both fractions was markedly decreased following cholera toxin injection . The ability of cholera toxin to induce both epidermal and dermal ornithine decarboxylase activity developed between 10 and 21 days after birth. Endocrinology, 1980 Dec, 107(6), 2076 - 81 Effects of thyrotropin and cholera toxin on the thyroidal adenylate cyclase-adenosine 3',5'-monophosphate system; Holmes SD et al.; The present experiments examined the relationship between cholera toxin and TSH stimulation of the adenylate cyclase system in bovine thyroid tissue . Preincubation of thyroid slices for 20 min at 4 C with a maximal concentration of cholera toxin (100 microgram/ml) did not impair the subsequent stimulation of cAMP by submaximal amounts of TSH (1 mU/ml) during a 5-min incubation at 37 C . Incubation of cholera toxin or TSH with mixed gangliosides, followed by the addition of thyroid slices resulted in inhibition of the cholera toxin but not the TSH stimulation of cAMP formation . Previous exposure of thyroid slices to TSH induced refractoriness to subsequent stimulation of cAMP formation by TSH, but the response to cholera toxin was unchanged . NAD is necessary for cholera toxin, but not TSH, stimulation of adenylate cyclase . In the absence of NAD, cholera toxin inhibited the effect of maximal concentrations of TSH and prostaglandin E1 on adenylate cyclase activity but had no effect on NaF stimulation . In the presence of NAD, the stimulation of adenylate cyclase activity of bovine thyroid plasma membranes by a maximal amount of TSH was not influeced by maximal amounts of cholera toxin . Cholera toxin had a biphasic action on the binding of {125I}iodo-TSH, with low concentrations enhancing and high concentrations inhibiting binding . TSH augmented the binding of {125I}iodo-cholera toxin over the range of 1-100 mU/tube . Cholera toxin at 10 microgram/ml maximally inhibited binding . In addition to the requirement for ribosylation of adenylate cyclase, the present results indicate that the mechanisms of action of TSH and cholera toxin on cAMP formation are different. Endocrinology, 1980 Dec, 107(6), 2045 - 50 Influence of cholera toxin on in vitro refractoriness to thyrotropin of thyroids from rats fed propylthiouracil; Zakarija M et al.; Using an increase in the concentration of cAMP as an index of stimulation, we previously reported that in vitro thyroid tissue of rats fed a goitrogenic diet (0.1% propylthiouracil in Purina) were unresponsive to TSH . We now show that the addition of cholera toxin (0.1-1.0 microM) to fragments of normal thyroid enhanced the concentration of cAMP . Subsequent exposure of the tissue to TSH resulted in a further increase in the concentration of cAMP, and there was statistical evidence of interaction or potentiation between the effects of TSH (20 mU/ml) and cholera toxin (1.0 microM) . With fragments of thyroid from animals fed propylthiouracil (i.e . unresponsive in vitro to TSH), an increase in the concentration of cAMP was effected by 1 or 9 microM cholera toxin, and prior exposure to 9 microM toxin caused the tissue to be responsive to TSH . Unresponsiveness of the goitrous tissue was associated with a reduced capacity of the membrane to bind {125I}iodo-TSH although the affinity of the binding sites was unaffected . Cholera toxin at 0.1 microM enhanced and at 1 microM diminished the binding of {125I}iodo-TSH to membranes from either normal or goitrous glands, and these effects also reflected influences on the capacity rather than on the affinity of the binding sites . It is postulated that the unresponsiveness to TSH of thyroid tissue from rats fed propylthiouracil represents a down-regulation of receptor capacity, and this is effected by the binding sites becoming relatively inaccessible, rather than nonexistent. Endocrinology, 1980 Dec, 107(6), 2051 - 4 Influences of cholera toxin on thyroid stimulation by thyrotropin and thyroid-stimulating antibody; Zakarija M et al.; Thyroid-stimulating antibody (TSAb) is an immunoglobulin G (IgG) occurring in the blood in hyperthyroid Graves' disease patients; it stimulates the thyroid in a manner analogous to the action of TSH, i.e . by activation of adenylate cyclase . Since cholera toxin is also known to stimulate thyroid adenylate cyclase, we studied possible interaction of the enterotoxin on effects of TSAb and TSH using slices of canine thyroid in vitro and an increase in the concentration of cAMP as endpoint . Normal human IgG, known to inhibit the binding of {125I}-iodo-TSH to thyroid membranes, decreased stimulation of thyroid slices by TSH; this inhibitory effect occurred also with preparations of TSAb (inevitably comprised mainly of normal IgG) that were themselves stimulatory . The cholera toxin effect was not prevented by normal IgG and, by factorial analysis of variance, was shown to potentiate the action of subsequently added TSAb or TSH . There was also positive interaction of the effect of TSAb with the combination of TSH and cholera toxin . The data indicate that responses of thyroid tissue to TSAb and TSH are readily influenced by effects of other membrane-active agents (in the present context, normal IgG and cholera toxin). Biull Eksp Biol Med, 1980 Nov, 90(11), 622 - 6 {Scanning electron microscopy and x-ray microanalysis of the small intestine of suckling rabbits exposed to cholera toxin}; Buravkov SV; Surface alterations and elemental distribution in small intestinal enterocytes of suckling rabbits were studied by scanning electron microscopy and x-ray microanalysis . The latter was performed on 10 mu thick freeze-dried cryosections . Cholera toxin was found to diminish the sodium and chloride content in the epithelial layer from the cryptae towards the tops of the villi, while in control animals, no difference in the elemental distribution was revealed . The changes in the enterocyte surface consisted in the disarrangement of the microvilli and appearance of bullous enlargements on their tops. Infect Immun, 1980 Nov, 30(2), 337 - 41 Intestinal immune response to cholera toxin: dependence on route and dosage of antigen for priming and boosting; Svennerholm AM et al.; The influence in immunization with cholera toxin of the route and antigen dose on intestinal antibody formation and protective immunity against experimental cholera was studied in mice . Administration by either the intravenous or oral route induced effective priming as well as boosting of mucosal immunity, with the effects on intestinal immunoglobulin A antitoxin synthesis and protective antitoxic immunity showing excellent concordance . A strong antigen dose dependence was found for both priming and boosting of the local immunity, irrespective of route . Very efficient high-dose priming did, however, partially decrease the dose dependence of the booster response and, conversely, a high booster dose partly overcame the relative inefficiency of low-dose priming . The results suggest that the amount of antigen reaching the immunocompetent cells in the gut rather than the route of administration per se determines the mucosal immunizing effect. Vopr Virusol, 1980 Nov-Dec, (6), 735 - 40 {Electron microscopic study of the structural organization of cholera phage C}; Degtiarev BM et al.; Electron microscopy methods were used to determine the main parameters of the structural organization of cholera "C" phage . The particles of the phage were found to consist of a capsid of icosahedral shape and a thin noncontractile process . The capsid with the triangulation number 7 consists of 72 morphological subunits and contains DNA with the molecular weight of (68.16 +/- 1.63) x 10(6) daltons . The process of the phage consists of 216 morphological subunits and ends with a peculiar adsorption apparatus including a distal filament and three fibrils with knobs at the ends. Invest Ophthalmol Vis Sci, 1980 Nov, 19(11), 1321 - 7 Cholera toxin stimulates adenosine 3',5'-monophosphate synthesis and epithelial wound closure in the rabbit cornea; Jumblatt MM et al.; Rabbit corneas were treated in vitro and in vivo with cholera toxin (CTX), a specific and irreversible activator of adenylate cyclase . Tissue pieces incubated in vitro in the presence of 10 mug/ml CTX for 15 min continuously synthesized adenosine 3',5'-monophosphate (cyclic AMP) at an increased rate for 3 hr in the absence of CTX in the medium . Corneas exposed for 10 min to CTX topically in vivo and after various time intervals incubated in vitro had an increased ability to synthesize cyclic AMP for at least 30 hr after topical treatment . Epithelial wounds, 6 mm in diameter, were made by brief exposure of corneas in vivo to filter disks soaked in heptanol . Wounds in corneas pretreated with CTX closed at a faster rate and earlier than wounds in corneas pretreated with inactivated CTX . We postulate that cyclic AMP mediates the initial events governing the rate of closure of an epithelial defect. Infect Immun, 1980 Oct, 30(1), 62 - 8 Suppression of the intestinal immune response to cholera toxin by specific serum antibody; Pierce NF; The possibility that preexisting specific serum antibody could suppress a defined mucosal immune response to a topically applied antigen was studied in rats . Hyperimmune serum antibody induced by parenteral immunization of rats with cholera toxoid markedly suppressed the mucosal immune response to enterically applied cholera toxin . Such antibody was far more suppressive than antibody induced by primary parenteral immunization, apparently due to its greater avidity . Transfusion of small amounts (25 to 100 microliter) of hyperimmune serum suppressed the primary mucosal antitoxin response, the development of specific memory in the mucosal immune system, and, somewhat less effectively, the secondary mucosal antitoxin response . Suppression was due largely to a direct effect of serum antibody upon the interaction of absorbed enteric antigen with lymphoid tissue in Peyer's patches and, possible, mesenteric lymph nodes; interference with antigen absorption played little or no role in the observed suppression . These results do not explain the previously reported suppressive effect of primary parenteral immunization on the mucosal immune response to cholera toxin . However, they support the notions that repeated parenteral immunization can evoke avid serum antibody without necessarily stimulating mucosa-associated lymphoid tissue and that such antibody can markedly suppress primary and secondary phases of the local immune response to mucosally applied antigen . Thus, a mechanism is demonstrated by which repeated parenteral immunization may adversely affect efforts to initiate or sustain protective mucosal immune responses. J Histochem Cytochem, 1980 Oct, 28(10), 1100 - 12 Surface distribution of monosialoganglioside GM1 on human blood cells and the effect of exogenous GM1 and neuraminidase on cholera toxin surface labeling . A quantitative immunocytochemical study; Ackerman GA et al.; The cholera toxin-colloidal gold-labeled IgG-F(ab')2 anticholera toxin ultrastructural immunocytochemical procedure was used for the localization of GM1 monosialoganglioside on the surface of human blood cells . The number of gold particles per micron of cell surface was counted and the data subjected to statistical analysis . Cholera toxin (CT) binding characteristics assessed in several subjects showed consistent labeling patterns for the various hemic cells, although some quantitative differences were noted in surface labeling densities between subjects . Neutrophils were invariably the most heavily labeled of the hemic cells, while lymphocytes, erythrocytes, and platelets exhibited only limited CT labeling . Exposure of hemic cells to neuraminidase induced a major increase in surface CT labeling that proved to be directly related to cell type and differed in many respects with the CT labeling pattern noted in nonenzyme treated cells . Newly exposed CT binding sites attributed to "masked" GM1 and/or to neuraminidase-transformed GD1a or GT1 gangliosides, showed that the number of new binding sites were nearly twice as abundant on platelet and monocyte sufaces as on the surfaces of neutrophil, lymphocyte, and erythrocyte populations . However, ratios of new CT binding sites to those normally available for CT binding were approximately 10:1 for erythrocytes, approximately 3--7:1 for lymphocytes, monocytes, and platelets, and approximately 1:1 for the neutrophil group . Exogenous GM1 was incorporated into the cell surface of the hemic cells in a differential manner . Platelets showed a dramatic increase in surface CT labeling, viz . approximately 12- to 20-fold, compared to that of other hemic cells; however, neutrophil and erythrocyte GM1 uptake was limited . Our studies have demonstrated that distinct differences exist in the extent of surface CT labeling of the various types of blood cells . They further indicated that the ability of the cell surface to incorporate exogenous GM1 may represent a differential expression of the physiochemical properties of the surface of the individual cell types. Acta Pharmacol Toxicol (Copenh), 1980 Sep, 47(3), 190 - 4 Effect of chlorpromazine on ion transport induced by cholera toxin, cyclic AMP and cyclic GMP in isolated mucosa from hen intestine; Lonnroth I et al.; The isolated short circuit mucosa of chicken colon was established as an in vitro model for studies of the pathophysiology of diarrhoea and the mechanism of action of antidiarrhoeic drugs . Cholera toxin, 10(-7) M, added to the mucosal aide of the preparation, caused in a delayed reaction a pronounced increase of short circuit current (Isc) . Cyclic AMP, which mediates the effect of cholera toxin (when added serosal) induced an immediate rise of Isc . Half maximal reaction was achieved at 3 mM cyclic AMP and maximal at 7 mM . The increase of Isc corresponded to the increase in the flux of chloride from serosa to mucosa . Unlike cyclic AMP, cyclic GMP almost equally stimulated sodium and chloride transport from serosa to mucosa . Unlike cyclic AMP, cyclic GMP almost equally stimulated sodium and chloride transport from serosa to mucosa, while the effect on Isc of the two nucleotides was additive . Chlorpromazine, which effectively reverses diarrhoea in cholera patients, totally normalized Isc after treatment with either cholera toxin, cyclic AMP or cyclic GMP . This reduction was achieved by a specific stimulation of transport of chloride from mucosa to serosa . The effect occurred also without previous treatment of the tissue with secretagogues (cholera toxin, cyclic nucleotides) . No change in mucosal resistance was induced by chlorpromazine or cyclic GMP while it was reduced by cyclic AMP. Ann Intern Med, 1980 Aug, 93(2), 284 - 5 Trifluoperazine reversal of secretory diarrhea in pancreatic cholera; Donowitz M et al.; Diarrhea in a patient with pancreatic cholera syndrome caused by a vasoactive intestinal polypeptide producing pancreatic islet-cell carcinoma responded rapidly and dramatically to the phenothiazine trifluoperazine . Treatment with intravenous somatostatin decreased the plasma vasoactive intestinal polypeptide level without changing the diarrhea . The chemotherapeutic agent chlorozotocin, the 2-chloroethyl analogue of streptozocin, caused a decrease in plasma vasoactive intestinal polypeptide but caused significant renal toxicity with proteinuria. Southeast Asian J Trop Med Public Health, 1980 Jun, 11(2), 294 - 301 Protection afforded by anti-hemolysin against V . cholerae El Tor infection in experimental cholera; Chaicumpa W et al.; Specific antisera to V . cholerae El Tor hemolysin were prepared . The sera exhibited the following characteristics: formed a single precipitin band in immunoelectrophoresis against the crude preparation of hemolysin, had no passive hemagglutinating antibodies against V . cholerae LPS sensitized cells, possessed neutralizing property to the homologous hemolysin, and afforded some small degree of protection to oral challenge of V . cholerae El Tor in experimental animals. Am J Vet Res, 1980 Jun, 41(6), 946 - 9 Persistent hog cholera infection detected during virulence typing of 135 field isolates; Carbrey EA et al.; During the hog cholera (HC) eradication program in the United States, 135 field isolates were characterized by inoculation into specific-pathogen-free pigs . This gave origin to the classification of 61 (45%) as high virulent, 37 (27%) as low virulent, 29 (22%) as avirulent or immunizing, and 8 (6%) as capable of causing persistent infection . The persistent infections caused by the eight isolates were of long durtion, lasting in one instance to 152 days . The persistently infected pigs remained relatively free of clinical signs of HC but had high concentrations of HC virus (HCV) in their blood . When 6 of these pigs were given a second inoculation (with the virulent Ames strain of HCV), 2 died while the health status of 4 remained unchanged. Gut, 1980 May, 21(5), 365 - 9 Enhancement by cholera toxin of IgA secretion from intestinal crypt epithelium; Hamilton SR et al.; Studies of the effects of cholera toxin on the intestine have produced conflicting results regarding stimulation of IgA secretion . In the present study rabbit ileal loops were perfused with saline, and the IgA content of the perfusate was assessed by immunoradiometric assay . Crypt epithelial IgA content in biopsies was studied by immunofluorescence . Cumulative loop fluid IgA production 300 minutes after exposure to cholera toxin was 6216 +/- 993 microgram/cm compared with 4646 +/- 953 microgram/cm in controls (P < 0 . 20) . However, rate of fluid IgA production above baseline at 300 minutes was 1742 +/- 181 microgram/h/cm in cholera loops and 1049 +/- 310 microgram/h/cm in controls, and the mean difference between the cholera and control loops was statistically significant (P < 0 . 05) . In biopsies, mean rank of crypt epithelial IgA at 300 minutes was decreased compared with controls (P < 0 . 05) . The findings of increased rate of fluid IgA production and decreased epithelial IgA suggest that a single dose of cholera toxin enhanced secretion of IgA from crypt epithelium into the intestinal lumen, although the magnitude of the enhancement was not great. Naunyn Schmiedebergs Arch Pharmacol, 1980 May, 312(1), 91 - 7 Comparative study of the effect of cholera toxin and sodium deoxycholate on the paracellular permeability and on net fluid and electrolyte transfer in the rat colon; Goerg KJ et al.; 1 . The effect of deoxycholate and cholera toxin on the transfer of water, sodium, potassium and chloride and on mucosal permeability was studied in perfusion experiments on rat colon in vivo . The influence of both secretagogues on surface morphology was assessed by scanning electron microscopy . 2 . Deoxycholate turned the absorption of water, sodium and chloride to secretion and enhanced potassium secretion . Cholera toxin induced water and sodium secretion, inhibited chloride absorption and enhanced potassium secretion . 3 . Deoxycholate increased reversibly the mucosal permeability as measured by the colonic clearance of 51CrEDTA and glucose, whereas cholera toxin decreased the colonic 51CrEDTA clearance . 4 . Deoxycholate caused protrusion of the luminal cell surface and an increase of exfoliation of epithelial cells . The epithelial continuity was preserved . The only change induced by cholera toxin was an enhanced mucus extrusion . 5 . Our results are consistent with the view that deoxycholate causes fluid secretion by filtration whereas cholera toxin enhances the secretory activity of the epithelium. Endocrinology, 1980 May, 106(5), 1532 - 6 Action of cholera toxin on hormone synthesis and release in GH cells: evidence that adenosine 3',5'-monophosphate does not mediate the decrease in growth hormone synthesis caused by thyrotropin-releasing hormone; Dannies PS et al.; We have examined the effects of cholera toxin, a specific probe for processes which are caused by an increase in cAMP, on clonal strains of rat pituitary cells (GH cells) in culture . We found that 5 ng/ml cholera toxin increased the amount of intracellular cAMP after a lag period of 30-60 min . After a similar lag period, cholera toxin increased the release of PRL into the medium by 50% and caused a decrease in intracellular PRL to 60% of control values at 90 min . PRL synthesis was increased to 100% above control after 1 week of treatment, and GH synthesis was elevated to 280% above control . TRH caused an increase in PRL release and synthesis but a decrease of GH synthesis . Depending on the dose, TRH prevented or reduced the cholera toxin-induced rise in GH synthesis . We conclude that the decrease in GH synthesis caused by TRH is not likely to be mediated through an increase of intracellular cAMP. J Biol Chem, 1980 Mar 25, 255(6), 2549 - 53 Identification of cholera toxin binding glycoproteins in rat intestinal microvillus membranes; Morita A et al.; Glycoproteins of the microvillus membranes from rat small intestinal epithelial cells were examined for their ability to bind cholera toxin . Membrane glycoproteins prepared by Ricinus communis agglutinin-Sepharose affinity chromatography, which were free of glycolipids, were shown to be able to form complexes with iodinated cholera toxin by gel filtration column chromatography . These glycoproteins were further characterized by subjecting the complex of tritiated cholera toxin receptors, cholera toxin, and anti-cholera toxin antibody to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography and by localizing cholera toxin binding glycoproteins on sodium dodecyl sulfate-gels using iodinated cholera toxin . In addition to glycolipids, at least 5 glycoproteins with molecular weights of 69,000, 90,000, 100,000, 114,000, and 132,000 were identified by both methods . These results suggest that microvillus membranes contain glycoprotein and glycolipid receptors for cholera toxin. Biochem J, 1980 Mar 15, 186(3), 749 - 54 Requirement for guanosine triphosphate for cholera-toxin-catalysed incorporation of adenosine diphosphate ribose into rat liver plasma membranes and for activation of adenylate cyclase; Doberska CA et al.; 1 . Cholera toxin was shown to require the presence of GTP to activate rat liver plasma-membrane adenylate cyclase . ATP did not affect the activation process . 2 . Cholera toxin catalysed the incorporation of 32P from NAD labelled in the alpha-phosphate group of the ADP moiety into a rat liver plasma-membrane protein with a subunit mol.wt . of 42 500 . This is taken to demonstrate ADP-ribosylation . The ADP-ribosylation of this protein also required GTP and was unaffected by ATP . 3 . Nicotinamide inhibited both the activation of adenylate cyclase by cholera toxin and the ADP-ribosylation of the protein of 42 500 subunit mol wt . Neither the activation nor the ADP-ribosylation could be reversed by treatment with nicotinamide in the presence of cholera toxin. Acta Paediatr Scand, 1980 Mar, 69(2), 225 - 9 Composition of the intestinal fluid and the functional jejunoileal junction in secretory diarrhea of cholera in children; Mahalanabis D; The study critically evaluates the changes in the chemical composition of the luminal fluid along the whole length of the small intestine in four children with acute cholera and in one with acute noncholeraic diarrhea . In the children with cholera the total CO2 content rose abruptly from a mean of 7.1 mEq/l to 19.6 mEq/l at about two thirds the tube distance from the ligament of Trietz to the end of the ileum and increased further distally . At around the same point the pH also rose and the chloride fell . It is proposed that this level of the small intestine where a sharp transition in total CO2 content occurs be regarded as the functional jejunoileal junction . Sodium and potassium levels were similar in the jejunum and the ileum and the measured osmolality could be accounted for by them . The child with noncholera diarrhea had a very different small intestinal composition i.e . the total CO2 and pH as well as the sodium level remained low while the measured osmolality was high, indicating a high osmotic gap . The presence of a large amount of organic acid anions of bacterial origin and carbohydrate breakdown products may fully explain the findings in this child . More studies, however, are needed on children with noncholera diarrhea to confirm these findings. J Cell Physiol, 1980 Mar, 102(3), 317 - 21 Cholera toxin and analogues of cyclic AMP stimulate the growth of cultured human mammary epithelial cells; Taylor-Papadimitriou J et al.; The growth of human epithelial cells is stimulated by cholera toxin and analogues of cyclic AMP, while the growth of breast derived fibroblasts is inhibited . These compounds have little effect on DNA synthesis in the absence of other mitogens but show a synergistic effect with serum and/or EGF . The results suggest that high intracellular levels of cyclic AMP in human mammary epithelial cells increase the growth response of the cell to mitogens. J Biol Chem, 1980 Feb 10, 255(3), 988 - 95 The role of the guanine nucleotide exchange reaction in the regulation of the beta-adrenergic receptor and in the actions of catecholamines and cholera toxin on adenylate cyclase in turkey erythrocyte membranes; Lad PM et al.; Several changes were noted in the characteristics of the turkey erythrocyte beta-adrenergic receptor and in the kinetic properties of adenylate cyclase following pretreatment of erythrocyte membranes with isoproterenol and GMP, and thorough washing to remove these agents . The changes include modifications in the binding of agonist (isoproterenol) and in revelation of marked effects of GTP on agonist binding; reduction in the lag in Gpp(NH)p activation of adenylate cyclase; short lived activation by GTP which is lengthened by treatment with cholera toxin and NAD prior to pretreatment with isoproterenol and GMP . Treatment with cholera toxin also shortened the lag in activation by Gpp(NH)p and increased the steady state levels of activation by both Gpp(NH)p and GTP . The following conclusions can be drawn: (i) catecholamines, in the presence of a guanine nucleotide, stimulate the exchange of bound and exogenous nucleotide; (ii) the exchange reaction is involved in both the activation of adenylate cyclase and in the reciprocal effects of hormone and guanine nucleotides on each other's binding: (iii) the beta-adrenergic receptor and nucleotide regulatory components are linked in turkey erythrocyte membranes; (iv) both cholera toxin and catecholamines, although by different mechanisms, stimulate the exchange reaction at the nucleotide regulatory sites. J Biol Chem, 1980 Jan 10, 255(1), 23 - 6 Potentiation of cholera toxin-stimulated cyclic AMP production in cultured cells by inhibitors of RNA and protein synthesis; Nickols GA et al.; Cyclic AMP increased 8- to 10-fold after a 3-h treatment with 6 nM cholera toxin in rat C6-2B astrocytoma cells . In the presence of cycloheximide, cholera toxin increased intracellular cyclic AMP about 50-fold . Qualitatively similar potentiation of cholera toxin action by cycloheximide was observed in isolated swine aortic vascular smooth muscle cells . Cycloheximide, by itself, had no effect upon cyclic AMP levels and did not alter the apparent Ka for cyclic AMP generation by cholera toxin in the cells . Also, cycloheximide did not appear to augment cholera toxin action via inhibition of cyclic nucleotide phosphodiesterase . Puromycin and actinomycin D also augmented cholera toxin action in C6-2B cells . Potentiation of cholera toxin-increased cyclic AMP formation by cycloheximide was correlated with the inhibition of {14C}leucine incorporation into protein . These results indicate that the ability of cholera toxin to stimulate cyclic AMP production in C6-2B astrocytoma and swine vascular smooth muscle cells is enhanced by inhibition of de novo protein synthesis. Ann Rech Vet, 1980, 11(1), 27 - 33 {Immunologic abnormalities in pigs with hog cholera virus infection (author's transl)}; Charley B et al.; The effects of an acute Hog Cholera Virus (HCV) infection upon immune functions of experimentally infected pis were studied . Leukopenia was found to occur in both vaccinated and non-vaccinated infected animals but without any decrease in lymphocyte proportion . Lymphocytes from infected pigs had an altered response to phytohemagglutinin (PHA) as judged by an in vitro tritiated thymidine uptake of PHA-stimulated lymphocyte cultures . The beginning of a secondary humoral immune response to lysozyme appeared to be significantly depressed in HCV diseased animals. Ann Rech Vet, 1980, 11(3), 313 - 9 {Hog cholera diagnosis: an improved technique of seroneutralization based on use of a cytolytic virus strain in microplate (author's transl)}; Laude H et al.; An improved technique for the detection of hog cholera virus (HCV) neutralizing antibodies is described, in which running of the test is greatly facilitated by use of a cytolytic strain of HCV . This strain was isolated from persistently infected IB-RS 2, and was shown to induce a distinct cytopathic effect in several pig kidney cell lines (Laude, 1978) . For the assay, serum samples at 1 : 10 are diluted serially twofold in disposable microplates, then 1 x 10(4) PFU of the virus-stock are added in each well . Trypsinized RP-TG cells are dispensed at 2 x 10(4)/well after 1 hour contact at 38 degrees C . After 4 days of incubation at 38 degrees C, plates are sequentially stained with neutral red and lugol, to make the undestroyed monolayers visualized . Neutralizing titre is expressed as the highest dilution of the serum affording a 75 percent protection of monolayer . This procedure has proved to be a labor saving technique yet being as reproducible and as sensitive as the immunofluorescence-tests . It combines the following advantages: 1) The immunofluorescence step is suppressed . 2) Results can be recorded without the aid of microscope . 3) The test is miniaturized . 4) Cultures of continuous cell lines are used . 5) The challenge virus is attenuated for the pig . Therefore this technique can be recommended for routine serological survey of the HCV-infection in pig-herds. J Cyclic Nucleotide Res, 1980, 6(5), 359 - 67 Inhibition of cholera toxin activation of the adenylate cyclase system in intact HeLa cells; Lin MC et al.; Cholera toxin treatment activates the adenylate cyclase in intact HeLa cells . However, pretreatment of the cells with chemicals known to inhibit receptor internalization and lysosomal processing blocks the toxin activation . The agents found to inhibit the effect of cholera toxin include methylamine, ammonium chloride, chloroquine and dansylcadaverine . These chemicals did not affect either the binding of )125I)-cholera toxin to HeLa cells nor the ability of A1 peptide to activate the adenylate cyclase in plasma membrane preparations . We conclude that these chemicals act on the processing of the toxin subsequent to its binding and that internalization and lysosomal processing mediate the release of the active fragment from cholera toxin, which activates the adenylate cyclase system. J Infect Dis, 1980 Jan, 141(1), 64 - 70 Adenosine diphosphate-ribosylation of adenylate cyclase catalyzed by heat-labile enterotoxin of Escherichia coli: comparison with cholera toxin; Gill DM et al.; The heat-labile enterotoxin of Escherichia coli, like cholera toxin, activates adenylate cyclase by catalyzing the transfer of adenosine diphosphate-ribose from HAD+ (oxidized nicotinamide adenine dinucleotide) to the guanyl nucleotide-dependent regulatory component of the cyclase . A preparation of enterotoxin that had been released from E . coli following exposure to polymyxin B and then partially purified was found to contain two enzymatically active peptides, one of about 29,000 and the other of about 24,000 daltons, which correspond in molecular size to the enzymatically active subunit A and fragment A1 of cholera toxin, respectively . As with cholera toxin, the enzymatic activity of E . coli enterotoxin was elevated by incubation with sodium dodecyl sulfate to release active peptides . Treatment with dithiothreitol, however, had no effect . Dithiothreitol activates subunit A of cholera toxin by reducing an internal disulfide bond, but no corresponding bond appears to be present in the partially purified E . coli enterotoxin. J Immunol, 1980 Jan, 124(1), 307 - 11 Priming and suppression of the intestinal immune response to cholera toxoid/toxin by parenteral toxoid in rats; Pierce NF et al.; Parenteral immunization of rats with cholera toxoid had both priming and suppressive effects upon the antitoxin response in jejunal lamina propria to locally applied toxoid/toxin . Priming was detected when parenteral toxoid was given i.p . but not i.v . or s.c., was enhanced by Freund's adjuvant, and appeared to reflect enhanced encounter of i.p . antigen with IgA-committed lymphocytes in extra-intestinal mucosa-associated lymphoid tissue . In contrast, suppression followed parenteral toxoid given i.p., i.v., or s.c.; suppression was antigen specific and lasted at least 16 weeks . Parenteral toxoid suppressed both primary and secondary types of mucosal antitoxin responses, ultimately preventing the generation of antitoxin-containing immunoblasts from Peyer's patches . Since suppression followed parenteral immunization by routes that did not provoke mucosal priming, it was, at least in those instances, not simply a regulatory consequence of mucosal priming . These results support the notion that priming and suppression of a specific mucosal immune response are independent effects of parenteral immunization that are probably determined by the distribution of antigen to mucosa-associated and systemic lymphoid tissue, respectively. Scand J Infect Dis Suppl, 1980, Suppl 24, 79 - 81 Effect of experimental trichinosis on intestinal secretion and on local antibody formation to cholera toxin; Ljungstrom I et al.; The life cycle of Trichinella spiralis, a parasitic nematode, has three main stages: intestinal, migration and muscular stage . The present study was initiated to clarify the possible effects of the various stages of the infection on (a) enterotoxin induced intestinal secretion and (b) development of local immunity to cholera toxin . During the intestinal stage of trichinosis in mice challenge of ligated loops with cholera toxin gave rise to significantly greater fluid accumulation than was demonstrated in uninfected animals . In contrast, during migration and early muscular stage the secretory response was markedly reduced whereas in late muscular stage the fluid accumulation was normal . Absorption studies revealed that the intestinal fluid uptake was normal during the migration and muscular stages while it was markedly decreased during the intestinal stage which could probably explain the increased fluid accumulation in response to enterotoxin at this time . The normal absorption during the other stages suggests a true inhibition of the secretory process . To study the antibody response to cholera toxin during the various stages of T . spiralis infection the mice were given repeated peroral immunizations according to a schedule known to induce immunity to experimental cholera in mice . We found that T . spiralis infected mice, in which the immunization started ("priming") during the intestinal stage, had a significantly reduced IgA response in the small intestine . On the other hand T . spiralis infection had much less, if any effect on the IgA response to cholera toxin when immunization started before the infection and only the booster dose was given in the intestinal stage or when both priming and boosting were done after the intestinal stage. Acta Physiol Scand Suppl, 1980, 481, 21 - 5 Cholera toxin interactions with lipid bilayers; Tosteson MT et al.; The purpose of the experiments described in this paper was to assess the binding of cholera toxin to bilayers containing its receptor, the monosialoganglioside, GMl . The assay was based on the fact that GMl confers on the bilayer a negative surface charge . The magnitude of this surface charge was estimated by measuring the electrical conductance (G) of the bilayers exposed to nonactin-K+ under conditions where G is directly proportional to the potassium concentration in the aqueous solutions immediatey adjacent to the membrane surface . When bilayers were formed from mixtures of GMl and glycerolmonooleate (GMO), it was found that the molar ratio of the lipids in the bilayer was the same as that in the membrane forming solution . It was further found that cholera toxin or the binding subunit of the toxin (choleragenoid) bind to GMO bilayers containing GMl (but not to GMO bilayers containing phosphatidyl serine or disialoganglioside GDla) . The value of the apparent dissociation constant for the binding of choleragen to its receptor was found to be 10(-11) M, comparable to values found in intact cells. J Membr Biol, 1980, 54(1), 61 - 72 Mechanism of action of cholera toxin: studies on the lag period; Fishman PH; The lag period for activation of adenylate cyclase by choleragen was shorter in mouse neuroblastoma N18 cells than in rat glial C6 cells . N18 cells have 500-fold more toxin receptors than C6 cells . Treatment of C6 cells with ganglioside GM1 increased the number of toxin receptors and decreased the lag phase . Choleragen concentration also effected the lag phase, which increased as the toxin concentration and the amount of toxin bound decreased . The concentration, however, required for half-maximal activation of adenylate cyclase depended on the exposure time; at 1.5, 24, and 48 hr, the values were 200, 1.1, and 0.35 PM, respectively . Under the latter conditions, each cell was exposed to 84 molecules to toxin . The length of the lag period was temperature-dependent . When exposed to choleragen at 37, 24, and 20 degrees C, C6 cells began to accumulate cyclic AMP after 50, 90, and 180 min, respectively . In GM1-treated cells, the corresponding times were 35, 60, and 120 min . Cells treated with toxin at 15 degrees C for up to 22 hr did not accumulate cAMP, whereas above this temperature they did . Antiserum to choleragen, when added prior to choleragen, completely blocked the activation of adenylate cyclase . When added after the toxin, the antitoxin lost its inhibitory capability in a time and temperature-dependent manner . Cells, however, could be preincubated with toxin at 15 degrees C, and the antitoxin was completely effective when added before the cells were warmed up . Finally, cells exposed to choleragen for less than 10 min at 37 degrees C accumulated cyclic AMP when shifted to 15 degrees C . Under optimum conditions at 37 degrees C, the minimum lag period for adenylate cyclase activation in these cells was 10 min . These findings suggest that the lag period for choleragen action represents a temperature-dependent transmembrane event, during which the toxin (or its active component) gains access to adenylate cyclase. J Membr Biol, 1980, 54(1), 51 - 60 Mechanism of action of cholera toxin: effect of receptor density and multivalent binding on activation of adenylate cyclase; Fishman PH et al.; Choleragen (cholera toxin) activates adenylate cyclase in HeLa cells, which contain less than 15,000 toxin receptors per cell, in a time- and concentration-dependent manner . Activation is blocked by the addition of the oligosaccharide chain of the ganglioside GM1, the receptor for the toxin . When the cells are preincubated with choleragen at 4 degrees C and then incubated with oligosaccharide at 37 degrees C, adenylate cyclase is activated less than 10% . When the preincubation phase is above 18 degrees C, adenylate cyclase becomes activated and the amount of activation depends on the time of preincubation . This inhibitory effect of the oligosaccharide is also observed with human lymphocytes and rat glial C6 cells but not with Friend erythroleukemic and mouse neuroblastoma N18 cells . The latter two cell lines have large numbers ot toxin receptors, whereas the former two cell lines have few receptors . When the number of toxin receptors in HeLa and C6 cells is increased by treating the cells with GM1, activation of adenylate cyclase by choleragen is no longer blocked by the oligosaccharide . The oligosaccharide has a corresponding effect on the displacement of bound 125I-choleragen . When bound to cells at 4 degrees C, most of the radiotoxin is displaced from HeLa, C6, and lymphocytes but not from Friend, N18, or HeLa cells pretreated with GM1 . In untreated HeLa cells, dissociation of toxin-receptor complexes by the oligosaccharide depends on the time and temperature of complex formation; above 18 degrees C, the toxin rapidly becomes stably bound to the cells . The inhibitory effect of GM1 oligosaccharide us reversible, as, once it is removed, the small amount of toxin that remains bound can activate adenylate cyclase . These results are consistent with a model in which choleragen, which is multivalent, must bind to several GM1 molecules on the cell surface in order to subsequently activate adenylate cyclase . Lateral mobility of toxin-receptor complexes may be required only to achieve multivalent binding in cells with few receptors. Neurol Res, 1980, 1(4), 333 - 9 The effect of cholera toxin on choroid plexus carbonic anhydrase activity in vitro; Feldman AM et al.; The effects of the adenylate cyclase agonists cholera toxin and prostaglandin E2 on carbonic anhydrase activity in vitro was measured in choroid plexuses isolated from Sprague-Dawley rats . Choroid plexuses were incubated in buffer at 38 degrees C (pH 7.4) with either cholera toxin or prostaglandin E2 (PGE2) at a concentration and for a time period that had been shown in earlier studies to result in maximal stimulation of cyclic AMP production . Cholera toxin (10 micrograms/ml) caused a twofold increase (p < .001) in choroid plexus carbonic anhydrase activity when cholera toxin treated plexuses {20.92 +/- .46 mol CO2/(min)(mg protein X 10(-8)} were compared with plexuses exposed to heat inactivated cholera toxin (10.92 +/- .43) . When choroid plexuses were homogenized and separated into a 10,000 g pellet and a supernatant fraction, the supernatant carbonic anhydrase was unresponsive to cholera toxin stimulation . In the pellet fraction, which contained all the cellular adenylate cyclase, challenge with cholera toxin produced a significant increase in carbonic anhydrase activity (p < .01) . Control activity was 10.9 +/- 1.2 mol CO2/(min)(mg protein X 10(-8), while carbonic anhydrase activity in fractions exposed to cholera toxin was 28.4 +/- 0.8 . PGE2 had no effect, however, upon choroid plexus carbonic anhydrase activity . Since both PGE2 and cholera toxin stimulate cyclic AMP production in vitro, a compartmental model of secretory control is proposed. Arkh Patol, 1980, 42(5), 75 - 83 {New data on the mechanisms of the effect of cholera toxin}; Shakhlamov BA; Data from the literature on cholera pathogenesis in man and experimental animals are presented . The essence of secretion and filtration theories of rapid dehydration of the intestinal tract as well as that of the secretion-filtration theory proposed by the author are discussed . The data of both national and foreign authors are used in the discussion of the mechanisms of cholera toxin action . New observations on changes in the enzyme content (adenylate- and guanylate-cyclase systems) as well as the data on changes of the element composition of epithelial cells of different parts of the small intestine villi, on the role of local immunity in prevention of cholera toxicity are presented from the author's own observations and those of the laboratory staff members. J Cyclic Nucleotide Res, 1979 Dec, 5(6), 435 - 47 Induction of refractoriness to isoproterenol by prior treatment of C6-2B rat astrocytoma cells with cholera toxin; Nickols GA et al.; Rat C6-2B astrocytoma cells responded to cholera toxin treatment with an 8-fold increase in intracellular cyclic AMP concentrations . Cyclic AMP levels began to rise 60--90 minutes after addition of the toxin and reached maximal concentrations in 3 hours . Cells exposed to cholera toxin and the phosphodiesterase inhibitor, 1-methyl-3-isobutylxanthine (MIX), displayed an increase in cyclic AMP of 15-fold . The peak isoproterenol response was reduced 80--90% in cells previously treated with cholera toxin . Cholera toxin-induced refractoriness was time dependent and was not altered by concurrent treatment with propranolol . Prolonged exposure of the cells to isoproterenol reduced the cyclic AMP response to cholera toxin by 80% . MIX augmented both cholera toxin-induced refractoriness and isoproterenol-induced refractoriness . Cycloheximide inhibited the full development of refractoriness to both cholera toxin and isoproterenol . These results indicate that C6-2B cell refractoriness to cholera toxin is mediated by cyclic AMP and requires new protein synthesis . Refractoriness in C6-2B cells does not appear to be agonist-specific and probably involves a common locus of action on adenylate cyclase beyond that of the membrane receptors for cholera toxin and isoproterenol. Experientia, 1979 Nov 15, 35(11), 1467 - 8 The effect of lidocaine on the secretion induced by cholera toxin in the cat small intestine; Cassuto J et al.; The intraluminal administration of lidocaine, a local anaesthetic agent, inhibits the net loss of fluid into the intestinal lumen produced by cholera toxin in the cat . It is suggested that the activation of a nervous reflex is involved in the pathogenesis of cholera. Infect Immun, 1979 Nov, 26(2), 594 - 8 Protection against experimental cholera by oral or parenteral immunization; Peterson JW; Comparisons were made between the antigenic potency and protective capacity of several cholera toxin derivatives . Rabbits were immunized parenterally with 50 microgram of cholera toxin, A subunit, B subunit, procholeragenoid, or Wyeth glutaraldehyde toxoid 20101 . Examination of the antibody response curves revealed that cholera toxin elicited serum antitoxin responses that rose more quickly than in the subunit-immunized animals; however, antitoxin levels were of the same magnitude after 10 weeks . Parenteral immunization with procholeragenoid evoked antibody titers that were similar to the toxin, whereas Wyeth toxoid yielded only one-tenth the level of antitoxin . Oral immunization with procholeragenoid as well as Wyeth toxoid resulted in lower serum antitoxin titers than that achieved with parenteral immunization, despite the oral administration of 10 times the parenteral dose . Analysis of protection against live-cell challenge revealed that parenteral administration of procholeragenoid provided the best protection against fluid accumulation . Oral immunization with procholeragenoid also was very effective, whereas oral immunization with B subunit or Wyeth toxoid resulted in minimal protection . Also, the A subunit provided surprisingly more protection than did cholera toxin. Acta Physiol Scand, 1979 Nov, 107(3), 239 - 49 Effects of cholera toxin on villous tissue osmolality and fluid and electrolyte transport in the small intestine of the cat; Hallback DA et al.; The effects of cholera toxin on tissue osmolality and on net transport rates of water, sodium, chloride and potassium as well as on unidirectional fluxes of water and sodium were studied in vivo . In all experiments the toxin caused a net secretion of water, sodium, chloride and potassium . The unidirectional sodium transport from tissue to lumen was increased while the flux in the opposite direction was reduced 180 min after cholera toxin instillation . Cholera toxin produced only a small reduction in the villous tissue hyperosmolality, created by the intestinal countercurrent exchanger . This reduction was far too small to explain the observed net secretion of fluid and solutes induced by the cholera toxin . Other mechanisms underlying the cholera secretion are discussed. No To Shinkei, 1979 Nov, 31(11), 1129 - 36 {Cholera toxin induced epileptogenic focus--special reference to cyclic AMP metabolism and epileptogenic focus (author's transl)}; Kakita K et al.; Epilepsy-like convulsive seizures have been induced by cholera toxin administration into the rat amygdaloid complex . Between the 8th and 48th hr after the administration, rhythmic spike discharges (1--3 spikes/sec) were electroencephalographically observed bilaterally in the amygdaloid complexes, and rats exhibited abnormal behaviors such as running, jumping, tail lifting, rearing, vocalization aggressive behavior, facial twitching and increased salivation . During these stages, high voltage spikes were intermittently observed with generalized convulsive seizures . Duration of the seizure was 1--2 min and the incidence was 0--6 times/hr . At 48 hrs after the administration or thereafter, convulsive seizures disappeared and electroencephalographic abnormalities were gradually normalized . Occasional rhythmic spike discharges, however, were observed more than 168 hrs after the administration . Since autoradiographic observations with 125I-labeled cholera toxin revealed that the injected toxin does not spread out at all from the injected site, the use of this toxin seems to be an ideal procedure to produce micro-epileptogenic foci . Cyclic AMP content as well as adenylate cyclase activity in the ipsilateral amygdaloid complex was significantly increased during preconvulsive and convulsive states . The administration of 5 x 10(-8) moles of dibutyryl cyclic AMP through the cannula implanted into the amygdaloid complex also induced behavioral and electroencephalographic abnormalities similar to those found in the cholera toxin-treated animals . These results suggest that cyclic AMP and/or cyclic AMP dependent neuronal mechanisms may play a significant role in the establishment of epileptogenic focus . Possible use of this animal model for the study of anti-epileptic drugs are also suggested. Zh Mikrobiol Epidemiol Immunobiol, 1979 Nov, (11), 78 - 82 {Immunomorphologic study of experimental enteric anc combined vaccination against cholera}; Nazarova LS et al.; As a result of the enteral and combined subcutaneous-enteral immunization of adult rabbits with cholerogen toxoid and the specific fraction of chemical cholera vaccine in tablets immunological transformation occurred in the organism and a "protective" barrier consisting of antibody-containing cells was formed in the intestine on days 3-5 . The combined method of immunization with cholera vaccine proved to be essentially as effective as enteral immunization in 2 administrations. Proc Natl Acad Sci U S A, 1979 Oct, 76(10), 5336 - 9 Ultrasensitive enzymatic radioimmunoassay: application to detection of cholera toxin and rotavirus; Harris CC et al.; Rotavirus and enterotoxin-producing bacteria are major causes of diarrheal disease in humans . A method of rapid diagnosis, ultrasensitive enzymatic radioimmunoassay, has been developed to quantitatively detect cholera toxin and rotavirus . The method uses features of both enzyme-linked immunosorbent assay and radioimmunoassay; however, the sensitivity of the assay is 100- to 1000-fold more sensitive than the two parent assays . Ultrasensitive enzymatic radioimmunoassay should also be useful in measuring other biologically important agents such as drugs and hormones. Infect Immun, 1979 Oct, 26(1), 235 - 9 Effect of cholera toxin on the antiviral and anticellular activities of human leukocyte interferon; Fuse A et al.; Cholera toxin added into cell cultures together with human leukocyte interferon inhibited the establishment of the antiviral state by interferon but not the anticellular activity of interferon in human cells . Sensitivities of various human cell lines to anticellular activities of interferon and cholera toxin were compared, but no direct correlation between both activities were demonstrated . These results suggest that antiviral and anticellular activities of interferon are due to different mechanism of actions, and cholera toxin does not act directly on the receptor site for interferon. Rev Epidemiol Sante Publique, 1979 Sep 18, 27(2), 121 - 32 A mathematical model for the 1973 cholera epidemic in the European Mediterranean region; Capasso V et al.; For the cholera epidemic that occurred in the European Mediterranean region in the summer of 1973, a simple deterministic mathematic model is proposed; it consists of a system of two ordinary differential equations which concern the evolution of the human infective population in a town community and of bacteria population in the sea . It is conjectured that the infection process obeys a non linear saturation-type law . A phase space analysis is performed for the system of equations . Conclusions are drawn which concern the evolution of the epidemic and which suggest some indications for the selection of public health policies . The validity of the model is compared with the available data for the town of Bari (Italy). Biochim Biophys Acta, 1979 Sep 3, 586(3), 518 - 27 ADP-ribosylation of membrane proteins and activation of adenylate cyclase by cholera toxin in fat cell ghosts from euthyroid and hypothyroid rats; Malbon CC et al.; Incubation of fat cell ghosts with activated cholera toxin, nucleoside triphosphate, cytosol, and NAD results in increased adenylate cyclase activity and the transfer of ADP-ribose to membrane proteins . The major ADP-ribose protein comigrates on sodium dodecyl sulfate-polyacrylamide gels with the putative GTP-binding protein of pigeon erythrocyte membranes (Mr 42 000), which is also ADP-ribosylated by cholera toxin . The treatment with cholera toxin enhances the stimulation of the fat cell membrane adenylate cyclase by GTP, but the stimulation by guanyl-5'-yl imidodiphosphate is unaltered . Subsequent stimulation of fat cell adenylate cyclase by 10 micrometers epinephrine is not particularly affected . These changes were qualititatively the same for membranes isolated from fat cells of hypothyroid rats . Although the cyclase of these membranes has a reduced response to epinephrine, guanyl-5'-yl imidodiphosphate or GTP, as compared to euthyroid rat fat cell membranes, the defect is not rectified by toxin treatment and cannot be explained by a deficiency in the cholera toxin target. J Neurobiol, 1979 Sep, 10(5), 429 - 40 Ganglioside patterns and cholera toxin--peroxidase labeling of aggregating cells from the chick optic tectum; Engel EL et al.; 2The ganglioside compositions of the chick optic tectum and aggregating tectal cell cultures were examined . Both showed similar trends in changes in ganglioside patterns during development . GD3 and GD1b were the predominant gangliosides early in development, while GD1a and several other multisialogangliosides increased in relative amounts with increasing age in vivo and in vitro . Four gangliosides were present early in development which have not previously been reported . These gangliosides are not present at later developmental times suggesting a possible role for them during the critical early stages of nervous tissue differentiation . Some differences were noted when comparing in vivo versus in vitro ganglioside patterns; these differences may possibly be due to the lack of normal retinotectal connections in the cultures . Cytochemical studies on the localization of the presumed cholera toxin--peroxidase binding site GM1 showed conjugate binding correlates with increasing levels of GM1 in the cultures . In older cultures, the conjugate was uniformly localized on all cells and processes in the aggregates . The conjugate also bound to synaptic membranes and intensely stained the synaptic cleft . This latter observation suggests an enrichment of GM1 in the synaptic cleft region. Can J Physiol Pharmacol, 1979 Sep, 57(9), 1004 - 10 Failure to reverse cholera toxin induced intestinal secretion by agents which decrease mucosal cAMP; Forsyth GW et al.; The feasibility of reducing intestinal secretion by the use of agents which decrease intestinal mucosal cAMP concentration has been investigated in the weanling pig and the rabbit . Three different agents for decreasing mucosal cAMP concentration were studied . The cyclic nucleotide phosphodiesterase activator, imidazole, significantly reduced mucosal cAMP concentrations only in the weanling pig . Intraluminal 2'-deoxyadenosine-3'AMP inhibited adenylate cyclase and caused a decrease in mucosal cAMP concentration in both the pig and the rabbit . The introduction of the heat-stable enterotoxin of Escherichia coli into pig jejunal segments also gave lowered mucosal cAMP concentrations . While these three agents effectively reduced cAMP concentrations in intestinal mucosa, they were ineffective in reducing the net fluid secretory effects of cholera toxin . Secretion caused by cholera toxin apparently persists independent of the temporary changes in cAMP concentration which can be induced by pharmacological agents. J Pharmacol Exp Ther, 1979 Sep, 210(3), 349 - 53 Effect of cholera enterotoxin on pacemaker rate and cyclic adenosine 3':5'-monophosphate in isolated rabbit sinoatrial node; Taniguchi T et al.; The positive chronotropic effect of cholera enterotoxin on isolated rabbit sinoatrial (S-A) node was investigated . This toxin produced a time and dose-related increase in pacemaker rate and cyclic adenosine 3':5'-monophosphate (cyclic AMP) levels and shifted to the left the dose-response curves of norepinephrine on the pacemaker rate and cyclic AMP content in the S-A node . Thus, the sensitivity of the S-A node to norepinephrine was increased by the toxin . These effects of the toxin were not blocked by propranolol . There was a linear relation between the increases in pacemaker rate and cyclic AMP content after application of both the toxin and norepinephrine . However, the slope of the regression line relating pacemaker rate to cyclic AMP level differed with these two agents . These results suggest that cholera enterotoxin increases pacemaker rate with activation of the adenylate cyclase system in the S-A node, but the mechanism differs from that of norepinephrine. Endocrinol Jpn, 1979 Aug, 26(4), 423 - 9 Prolonged stimulation of adenylate cyclase activity and testosterone production by cholera enterotoxin with suppression of gonadotropin release in rats; Sato K et al.; Endocrine effects of cholera enterotoxin (CET) on male gonads were investigated in normal and hypophysectomized rats . After intratesticular injection of 5 micrograms of CET in the bilateral testes of normal rats, serum testosterone concentration remarkably increased after 24 hr, remained significantly elevated for at least 3 days and returned to the control level in 7 days . Serum LH level decreased in the undetectable range after 1--3 days; serum FSH level also significantly decreased after 3 days . Both gonadotropin levels increased 28 days after the injection, when the CET-injected testis decreased in weight and was accompanied by marked loss of germinal cells . When 5 micrograms of CET was injected intratesticularly in the bilateral testes of hypophysectomized rats, adenylate cyclase activity of a CET-injected testis was remarkably stimulated after 6 hr, remained four times elevated for at least 3 days and returned to the control level in 7 days . In relatively good accordance with the increase in adenylate cyclase activity, testosterone content remarkably enhanced in the CET-injected testis . These in vivo data indicate that the intratesticular injection of CET prolongedly stimulates the adenylate cyclase activity of testicular cells including Leydig cells and increases testosterone production, and suggest that the prolonged enzyme stimulation results in the sustained elevation of serum testosterone concentration for at least 3 days, causing the stimulation of the negative feedback mechanism of hypophysealtesticular axis to decrease serum LH levels in the undetectable range. J Histochem Cytochem, 1979 Aug, 27(8), 1165 - 6 The use of lectins and cholera toxin for the detection of surface carbohydrates of cultured neurons and neuroblastoma; Gonatas NK; Conjugates of horseradish peroxidase with the lectins ricin (d-galactose), wheat germ agglutinin (N-acetylglucosamine), phytohemagglutinin (N-acetylgalactosamine), and with cholera toxin (GM1 ganglioside) were used for a cytochemical detection of corresponding termin al carbohydrates, or glycolipids on cell surfaces of cultured neurons and neuroblastoma cells . Cells were labeled at 4 degrees C with the above ligands and their adsorptive endocytosis was studied after incubations at 37 degrees C in a medium free of ligand . Peroxidase was detected by the method of Graham and Karnovsky (J . Histochem . Cytochem . 14:291, 1966) . Lectins and cholera toxin underwent endocytosis in cisternae and vesicles of GERL (Golgi-Endoplasmic Reticulum-Lysosome) . We suggest that GERL is the primary ercipieint of adsorptively endocytosed plasma membrane "receptor"-ligand complexes which are thus degraded or possibly reutilized (recycling) . Wheat germ agglutinin-horseradish peroxidase conjugates used in vivo for studies of retrograde axonal transport were significantly more sensitive than free horseradish peroxidase. J Biol Chem, 1979 Jul 10, 254(13), 5849 - 54 Enzymic activity of cholera toxin . I . New method of assay and the mechanism of ADP-ribosyl transfer; Mekalanos JJ et al.; We tested various methods of assaying the ADP-ribosyltransferase activity of cholera toxin using artificial acceptors of the ADP-ribosyl group . Any of several proteins or poly(L-arginine) could be used with {adenine-14C}NAD+ as ADP-ribosyl donor, but this method was not ideal because of the heterogeneity of potential acceptor groups and the necessity of using costly labeled NAD+ . We, therefore, developed an alternative assay using a synthetic low molecular weight acceptor, 125I-N-guanyltyramine (125I-GT) . 125I-GT was specifically ADP-ribosylated by thiol-treated cholera toxin or its A1 peptide in the presence of beta-NAD . ADP-ribosyl-125I-GT was quantified after separation from unreacted 125I-GT by batch absorption of the latter to cation exchange resins . Analysis of the kinetics of ADP-ribosylation of 125I-GT indicated that the reaction proceeds by a sequential rather than a ping-pong mechanism . The Km values for NAD+ and 125I-GT were 3.6 mM and 44 microM, respectively . L-Arginine was a competitive inhibitor of 125I-GT (KI = 75 mM), but was at least 1000-fold less active than 125I-GT as an ADP-ribose acceptor. Zentralbl Bakteriol {Orig A}, 1979 Jul, 244(2-3), 181 - 91 {Studies on the increase of weights of lymphatic glands, of lymph and peritoneal fluid and their contents of chymotrypsin and virus in pigs suffering hog cholera (author's transl)}; Korn G; Swine fever is conceived as a disorder of the enzyme systems, that are controled by serine proteases . The virus is replicated in the cells of the lymphomycoid complex, whereby the production of a chymotrypsin is induced . In swine fever the lymphatic glands and the lymph flow are increased . Fifteen normal pigs had chymotrypsin contents in the lymph of the body lymphnodes of 0,4 U/l, nine pigs suffering hog cholera 1,5 U/l . In the intestinal lymphnodes the chymotrypsin concentration was normally 2,9 U/l and in swine fever 3,5 U/l . Chymotrypsin which is present may induce the production of further chymotrypsin . Fourteen pigs suffering from swine fever showed increased peritoneal fluids (50 to 120 ml), whereby chymotrypsin was found in 5 cases . The lymphflow was assumed to be five times higher, when compared to control animals . This entails a seven-fold increase of chymotrypsin which enters the blood stream . In some cases the virus titers are higher in the lymph specimen and peritoneal fluids than in the serum . Increase of chymotrypsin concentration reduces the resistance of the virus in the lymph . Obviously the virus is spread in the body migrating with the lymph flow . However, the increasing chymotrypsin concentration seems to inactivate the virus and lymph retains its defense character . Detection of the fluorescent antigen is correlated with the evidence of the proteolytic precipitating antigen . After infection with the virus of swine vesicular disease increase of chymotrypsin is also evidenced in the lymph but to a lower degree . Therefore in swine fever the lymphnodes cause chymotrypsin formation to an extent which may explain the pathophysiological disorders in those physiological systems, that are controled by serine proteases. Infect Immun, 1979 Jul, 25(1), 187 - 90 Inhibition by cholera toxin of rat polymorphonuclear leukocyte chemotaxis demonstrated in vitro and in vivo; Roch-Arveiller M et al.; The effect of cholera toxin on the chemotaxis of rat polymorphonuclear leukocytes (PMN) was studied using a technique in which