scholarly journals A tripartite cytolytic toxin formed by Vibrio cholerae proteins with flagellum-facilitated secretion

2021 ◽  
Vol 118 (47) ◽  
pp. e2111418118
Author(s):  
Aftab Nadeem ◽  
Raghavendra Nagampalli ◽  
Eric Toh ◽  
Athar Alam ◽  
Si Lhyam Myint ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Gene Cluster ◽  
Vibrio Anguillarum ◽  
Model Organism ◽  
Human Colon ◽  
Site Directed Mutagenesis ◽  
C Elegans ◽  
Colon Carcinoma Cells ◽  
Virulence Potential

The protein MakA was discovered as a motility-associated secreted toxin from Vibrio cholerae. Here, we show that MakA is part of a gene cluster encoding four additional proteins: MakB, MakC, MakD, and MakE. MakA, MakB, and MakE were readily detected in culture supernatants of wild-type V. cholerae, whereas secretion was very much reduced from a flagellum-deficient mutant. Crystal structures of MakA, MakB, and MakE revealed a structural relationship to a superfamily of bacterial pore-forming toxins. Expression of MakA/B/E in Escherichia coli resulted in toxicity toward Caenorhabditis elegans used as a predatory model organism. None of these Mak proteins alone or in pairwise combinations were cytolytic, but an equimolar mixture of MakA, MakB, and MakE acted as a tripartite cytolytic toxin in vitro, causing lysis of erythrocytes and cytotoxicity on cultured human colon carcinoma cells. Formation of oligomeric complexes on liposomes was observed by electron microscopy. Oligomer interaction with membranes was initiated by MakA membrane binding followed by MakB and MakE joining the assembly of a pore structure. A predicted membrane insertion domain of MakA was shown by site-directed mutagenesis to be essential for toxicity toward C. elegans. Bioinformatic analyses revealed that the makCDBAE gene cluster is present as a genomic island in the vast majority of sequenced genomes of V. cholerae and the fish pathogen Vibrio anguillarum. We suggest that the hitherto-unrecognized cytolytic MakA/B/E toxin can contribute to Vibrionaceae fitness and virulence potential in different host environments and organisms.

scholarly journals A tripartite cytolytic toxin formed by Vibrio cholerae proteins with flagellum-facilitated secretion

2021 ◽  
Author(s):  
Aftab Nadeem ◽  
Raghavendra Nagampalli ◽  
Eric Toh ◽  
Athar Alam ◽  
Si Lhyam Myint ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Gene Cluster ◽  
Human Colon ◽  
Site Directed Mutagenesis ◽  
Cloning And Expression ◽  
C Elegans ◽  
Virulence Potential ◽  
Organism Model ◽  
Type V

The protein MakA was discovered as a motility-associated secreted toxin from Vibrio cholerae, Here, we show that MakA is part of a gene cluster encoding four additional proteins: MakB, MakC, MakD and MakE. The MakA, MakB and MakE proteins were readily detected in culture supernatants of wild type V. cholerae whereas secretion was very much reduced from a flagellum deficient mutant. Crystal structures of MakA, MakB and MakE revealed structural relationship to a superfamily of bacterial pore-forming proteins. Cloning and expression of MakA/B/E in Escherichia coli resulted in toxicity of the bacteria towards Caenorhabditis elegans used as a predatory organism model. None of these Mak proteins alone or in pairwise combinations were cytolytic but an equimolar mixture of MakA, MakB and MakE acted as a tripartite cytolytic toxin in vitro causing lysis of erythrocytes and cytotoxicity on cultured human colon carcinoma cells. Formation of oligomeric complexes on liposomes was observed by electron microscopy. Oligomer interaction with membranes was initiated by MakA membrane binding followed by MakB and MakE joining in formation of a pore structure. A predicted membrane insertion domain of MakA was shown by site-directed mutagenesis to be essential for toxicity towards C. elegans. Bioinformatic analyses revealed that the makCDBAE gene cluster is present as a novel genomic island in the vast majority of sequenced genomes of V. cholerae and the fish pathogen V. anguillarum. We suggest that the hitherto unrecognized cytolytic MakA/B/E toxin can contribute to Vibrionaceae fitness and virulence potential in different host environments and organisms.

The influence of extracts from Rubus caesius leaves on human colon carcinoma cells cultured in vitro

Planta Medica ◽  
2014 ◽  
Vol 80 (16) ◽  
Author(s):  
R Paduch ◽  
M Tomczyk ◽  
A Wiater ◽  
A Dudek ◽  
M Pleszczynska ◽  
...  
Keyword(s):  
Colon Carcinoma ◽  
Human Colon ◽  
Carcinoma Cells ◽  
Colon Carcinoma Cells ◽  
Human Colon Carcinoma ◽  
Cells Cultured

scholarly journals The Effect of Water-Soluble Polysaccharide from Jackfruit (Artocarpus heterophyllus Lam.) on Human Colon Carcinoma Cells Cultured In Vitro

Plants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 103
Author(s):  
Adrian Wiater ◽  
Roman Paduch ◽  
Sylwia Trojnar ◽  
Adam Choma ◽  
Małgorzata Pleszczyńska ◽  
...  
Keyword(s):  
Biological Activity ◽  
Tumor Cells ◽  
Human Colon ◽  
Carcinoma Cells ◽  
Water Soluble ◽  
Artocarpus Heterophyllus ◽  
Colon Carcinoma Cells ◽  
Human Colon Carcinoma ◽  
Soluble Polysaccharide

Various phytochemical studies have revealed that jackfruit (Artocarpus heterophyllus Lam.) is rich in bioactive compounds, including carotenoids, flavonoids, volatile acids, tannins, and lectins. The aim of the study was to analyze the biological activity of water-soluble polysaccharide (WSP) isolated from jackfruit and to assess its immunomodulatory, cytotoxic, and anti-oxidative effects on human colon carcinoma cells in vitro. The neutral red (NR) uptake assay revealed no toxic influence of the polymer on the viability of tumor cells (HT29 and SW620). After 24 h and 48 h of incubation, the cellular viability was not lower than 94%. The metabolic activity of the cells (MTT) at the compound concentration of 250 µg/mL was higher than 92% in comparison to the control. WSP (250 µg/mL) exerted no significant effect on the morphology of the cells was determined by May-Grünwald-Giemsa staining. WSP changed nitric oxide (NOx) production by the tumor cells depending on the time of incubation and prior 2-h stimulation of the cells with E. coli 0111:B4 LPS. It significantly stimulated IL-1β production by the tumor cells. The IL-6 level increased but that of IL-10 decreased by a WSP concentration-dependent manner. No such effect was detected in SW620. The WSP had antioxidant properties. In conclusion, water-soluble polysaccharide isolated from A. heterophyllus exhibits significant biological activity towards many types of both normal and cancerous cells. Therefore, it may be considered as a useful agent in the protection of human health or in functional and dietary nutrition.

scholarly journals TGF-beta 1 is an autocrine-negative growth regulator of human colon carcinoma FET cells in vivo as revealed by transfection of an antisense expression vector.

1992 ◽  
Vol 116 (1) ◽  
pp. 187-196 ◽  
Author(s):  
S P Wu ◽  
D Theodorescu ◽  
R S Kerbel ◽  
J K Willson ◽  
K M Mulder ◽  
...  
Keyword(s):  
Cell Growth ◽  
Colon Carcinoma ◽  
Growth Regulator ◽  
Human Colon ◽  
Tgf Beta ◽  
Transfected Cells ◽  
Colon Carcinoma Cells ◽  
Human Colon Carcinoma

Transforming growth factor-beta 1 (TGF-beta 1) has previously been implicated as a potential negative autocrine or paracrine growth regulator of certain cell types (Arteaga, C. L., R. J. Coffey, Jr., T. C. Dugger, C. M. McCutchen, H. L. Moses, and R. M. Lyons. 1990. Cell Growth & Differ. 1:367-374; Hafez, M. M., D. Infante, S. Winawer, and E. Friedman. 1990. Cell Growth & Differ. 1:617-626; Glick, A. B., K. C. Flanders, D. Danielpour, S. H. Yuspa, and M. B. Sporn. 1989. Cell Regulation. 1:87-97). This is based mainly on experiments assessing the effects of exogenous TGF-beta 1 or neutralizing antibodies to TGF-beta 1 on normal or tumor cell proliferation in vitro. However, direct evidence demonstrating such a negative regulation of tumor cell growth in vivo is still lacking. To overcome this problem we have constructed and used an antisense expression vector for TGF-beta 1 as a means of regulating endogenous TGF-beta 1 expression in tumor cells. Antisense-transfected FET human colon carcinoma cells showed a fivefold reduction in TGF-beta 1 mRNA and 15-fold reduction in TGF-beta 1 secretion. Antisense mRNA was detected in transfected cells by an RNase protection assay. Compared to control cells, cultured antisense-transfected cells showed a reduction in lag phase time rather than a change in doubling time. Cloning efficiencies of transfected cells were four times greater than control cells in anchorage-independent assays. Control cells did not form tumors at 5 x 10(5) in athymic nude mice. Antisense-transfected cells formed tumors in 40% of animals injected. At higher inocula (1 x 10(6) cells) antisense-transfected cells formed tumors in 100% of animals injected, but control cells still failed to form tumors. These results show that TGF-beta 1 acts as a negative growth regulator of human colon carcinoma cells in vivo as well as in vitro. Acquisition of partial or full resistance to such inhibitory effects may therefore contribute to tumor development and progression.

An interaction between human colon carcinoma cells and hepatocytes activates transforming growth factor-β1 in vitro

1999 ◽  
Vol 142 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Hideki Nishibori ◽  
Masahiko Watanabe ◽  
Shin Narai ◽  
Tetsuro Kubota ◽  
Chitose Matsubara ◽  
...  
Keyword(s):  
Growth Factor ◽  
Colon Carcinoma ◽  
Transforming Growth Factor ◽  
Human Colon ◽  
Transforming Growth Factor Β1 ◽  
Carcinoma Cells ◽  
Colon Carcinoma Cells ◽  
Human Colon Carcinoma

scholarly journals Astaxanthin extends lifespan via altered biogenesis of the mitochondrial respiratory chain complex III

2019 ◽  
Author(s):  
Ronit Hoffman ◽  
Laure D. Sultan ◽  
Ann Saada ◽  
Joseph Hirschberg ◽  
Oren Osterzetser-Biran ◽  
...  
Keyword(s):  
Model Organism ◽  
Chain Complex ◽  
Mitochondrial Respiratory Chain ◽  
Industrial Applications ◽  
Complex Iii ◽  
Life Extension ◽  
Mitochondrial Respiratory Chain Complex ◽  
C Elegans ◽  
Species Effect

AbstractAstaxanthin is a keto-carotenoid produced in some bacteria and algae, which has very important industrial applications (i.e., in cosmetics, coloring additive in aquaculture and as a dietary supplement for human). Here, we analyzed the molecular basis of Astaxanthin-mediated prolongevity in the model organism, Caenorhabditis elegans. The increased lifespan effects of Astaxanthin are restricted in C. elegans to the adult phase and are uninfluenced by various other carotenoids tested. Genetic analyses indicated that the Astaxanthin-mediated life-extension relies on mitochondria activity, via the Rieske iron-sulfur polypeptide-1 (ISP-1), but is not influenced by the functions of other known longevity-related gene-loci, including CLK-1, DAF-2, DAT-16, EAT-2, GAS-1 GLP-1 or MEV-1. Biochemical analyses of native respiratory complexes showed that Astaxanthin affects the biogenesis of holo-complex III (and likely supercomplex I+III, as well). Effects on holo-CIII assembly and activity were also indicated by in-vitro assays, with mitochondria isolated from worms, rodents, human and plants, which were treated with Astaxanthin. These data indicated a cross-species effect on the oxidative phosphorylation (OXPHOS) machinery by the carotenoid, and provide with further insights into the molecular mechanism of animals longevity extension by Astaxanthin.Significance StatementAstaxanthin is a widely consumed pigment by animals and human. In this study we find that Astaxanthin, but not other tested carotenoids, significantly extends the lifespan of animals by affecting respiratory complex III (CIII) biogenesis of the mitochondria, in plants, C. elegans, rodents and human. We further propose a model to try explaining this effect of astaxanthin on animals’ longevity.

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