Assay of the Heat-Labile Enterotoxin of Escherichia Coli in Infant Rabbits

Burgess, M N; Melling, J.; Mullan, N. A.; Newsome, P. M.

doi:10.1099/00222615-12-3-291

Cited by 8 publications

(5 citation statements)

References 17 publications

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“…Since H ϩ ,K ϩ -ATPase expression and gastric acid secretion are upregulated during fetal development and neonatal maturation (4,36), we examined the maturation of CA IX expression in the proximal gastrointestinal tract. In two separate rabbit litters, tissue was isolated from two to three rabbits at each time point, and tissue from one of the rabbit pairs was used for examination of CA IX mRNA abundance by quantitative real-time RT-PCR, whereas the other was used for analysis of protein expression by Western blotting.…”

Section: Ca IX Expression Is Induced During Rabbit Maturationmentioning

confidence: 99%

Expression of membrane-associated carbonic anhydrase isoforms IV, IX, XII, and XIV in the rabbit: induction of CA IV and IX during maturation

Purkerson¹,

Schwartz²

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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Several carbonic anhydrase (CA) isoforms are associated with plasma membranes. It is probable that these enzymes interact with anion transporters to facilitate the movement of HCO3− into or out of the cell. A better knowledge of CA isoform expression in a given tissue would facilitate a systematic examination of any associations with such transporters. We examined the expression of CAs IV, IX, XII, and XIV mRNAs in rabbit tissues, including kidney, heart, lung, skeletal muscle, liver, pancreas, gall bladder, stomach, small intestine, colon, and spleen, using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). CA IV mRNA was mainly in kidney, heart, lung, colon, and gall bladder. CA IX mRNA was restricted to stomach, gall bladder, duodenum, and early jejunum. CA XII mRNA was found in kidney and colon. CA XIV mRNA was localized to heart, lung, skeletal muscle, and liver. The data indicate that there are different patterns of CA expression in various tissues: CA IX was expressed in the proximal gastrointestinal tract, whereas CA XII and CA IV were more distal. CA IV and CA XII are important kidney isoforms. CA XIV was abundant in metabolically active tissues such as liver, heart, lung, and skeletal muscle. Some significant species differences were noted in the expression of some of these isoforms; for example, CA XIV is not expressed in rabbit kidney, despite being abundant in mouse kidney. Maturational studies showed that the expression of CA IX mRNA and protein increased markedly with weaning (∼3–4 postnatal wk) and was well correlated with the maturational expression of the α-subunit of the gastric H+,K+-ATPase, suggesting that function of CA IX and the gastric H+ pump might be linked in the digestion of adult foodstuffs. The unique pattern of membrane-bound CA isoforms suggests different functional associations with transporters, depending on the physiological demands on the tissue.

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Section: Ca IX Expression Is Induced During Rabbit Maturationmentioning

confidence: 99%

Expression of membrane-associated carbonic anhydrase isoforms IV, IX, XII, and XIV in the rabbit: induction of CA IV and IX during maturation

Purkerson¹,

Schwartz²

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Enterotoxin identification methods can be performed using animal models (rabbit ileal loops method) [15] and cell lines, referred to as the golden standard in LT toxin expression detection. The method using cell lines detects the cytopathic effect caused by the enterotoxin on the CHO and Y1 cell line (abnormalities of cell shape) [6,16,17].…”

Section: Discussionmentioning

confidence: 99%

The detection and expression of enterotoxinencoding lth gene among Klebsiella spp. isolated from diarrhoea

et al. 2013

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“…In a recent paper by Burgess et al (1979) describing the assay of heat-labile enterotoxin of Escherichia coli in infant rabbits, the authors discussed an attempt to increase yields of enterotoxin by the method of lincomycin induction, as originally reported from this laboratory (Levner, Wiener and Rubin, 1977). I feel obliged to take issue with certain conclusions arrived at by these authors which might unjustifiably discourage other workers from using this convenient technique.…”

Section: Letters To the Editors Effect Of Lincomycin On The Productiomentioning

confidence: 99%

“…H. LEVNER Department of Research and Development, Wyeth Laboratories, Philadelphia, Pa 19 101, USA Dr Levner is correct to point out that we compared toxin yields from lincomycin-resistant mutants of strain P307 grown in the presence of lincomycin, with the yield from strain P307 grown conventionally (Burgess et al 1979).…”

Section: Letters To the Editors Effect Of Lincomycin On The Productiomentioning

confidence: 99%

Letters to the Editors: EFFECT OF LINCOMYCIN ON THE PRODUCTION OF HEAT-LABILE ENTEROTOXIN BY ESCHERICHIA COLI

Levner¹,

Burgess²,

Newsome³

et al. 1980

Journal of Medical Microbiology

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In a recent paper by Burgess et al. (1979) describing the assay of heat-labile enterotoxin of Escherichia coli in infant rabbits, the authors discussed an attempt to increase yields of enterotoxin by the method of lincomycin induction, as originally reported from this laboratory (Levner, Wiener and Rubin, 1977). I feel obliged to take issue with certain conclusions arrived at by these authors which might unjustifiably discourage other workers from using this convenient technique.Contrary to their statement, the authors did not demonstrate that "lincomycin . . . (was) found not to increase the yield of heat-labile enterotoxin from E. coli strain P307", since no data were presented, or referred to, regarding toxin production as a function of lincomycin concentration for strain P307. Indeed, the only data comparing toxin production for single strains grown with and without lincomycin (their table V) showed that, in five of five cases, increases of from 2-fold to more than 14-fold were obtained with lincomycin.The basis for the above statement and for their statement that they were unable to confirm our report of lincomycin-induced increases in enterotoxin yield appears to be that spontaneously isolated lincomycin-resistant variants grown with lincomycin produced no more enterotoxin than did the sensitive parent strain P307 grown without it. In our 1977 paper we compared yields of enterotoxin from various enterotoxigenic strains of E. coli, and from Vibrio cholerae strain 569B, with yields from lincomycin-resistant isolates, grown with and without the drug. It is true that all the resistant isolates grown with lincomycin yielded much more toxin than did the sensitive parent strains grown without it. We have generally found this to be true, and the results of Burgess et al. (1979) with strain P307, which we have not examined, are certainly in contrast to our experience. However, since the resistant isolates were not characterised either by us or by Burgess et al. (1979) and have an undetermined genetic relationship to the parent strains, the significance of this latter comparison is unclear. Our point in presenting these data was that lincomycin resistance was not sufficient in itself to confer higher enterotoxigenicity; the presence of the drug during growth was required. Induction could be obtained with either "sensitive" or "resistant" strains as long as appropriate levels of lincomycin were used, although higher yields of enterotoxin were generally obtained in the latter case.I suggest that anyone looking for a means of obtaining improved enterotoxin yield from any specific enterotoxigenic strain of E. coli or V. cholerae begin by looking at yield as a function of lincomycin concentration for that strain. Under our growth conditions (Levner et al., 1977), optimal induction, in terms of total enterotoxin yield per ml of culture, was found to occur at lincomycin concentrations which resulted in optical densities (550 nm) at 24 h of about one-half that of cultures grown without the drug.

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Assay of the Heat-Labile Enterotoxin of Escherichia Coli in Infant Rabbits

Cited by 8 publications

References 17 publications

Expression of membrane-associated carbonic anhydrase isoforms IV, IX, XII, and XIV in the rabbit: induction of CA IV and IX during maturation

Expression of membrane-associated carbonic anhydrase isoforms IV, IX, XII, and XIV in the rabbit: induction of CA IV and IX during maturation

The detection and expression of enterotoxinencoding lth gene among Klebsiella spp. isolated from diarrhoea

Letters to the Editors: EFFECT OF LINCOMYCIN ON THE PRODUCTION OF HEAT-LABILE ENTEROTOXIN BY ESCHERICHIA COLI

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