Enteropathogenic Escherichia coli (EPEC) infection inhibits intestinal vitamin C transporter function and expression: in vitro and in vivo studies

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Christopher W. Heskett ◽  
Trevor Teafatiller ◽  
Carly Hennessey ◽  
Melanie G. Gareau ◽  
Jonathan S. Marchant ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Vitamin C ◽  
In Vivo Studies ◽  
Enteropathogenic Escherichia Coli

scholarly journals Localized adherence by enteropathogenic Escherichia coli is an inducible phenotype associated with the expression of new outer membrane proteins.

1991 ◽  
Vol 174 (5) ◽  
pp. 1167-1177 ◽  
Author(s):  
J Vuopio-Varkila ◽  
G K Schoolnik
Keyword(s):  
Escherichia Coli ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
De Novo ◽  
Outer Membrane Proteins ◽  
Temporal Correlation ◽  
Enteropathogenic Escherichia Coli ◽  
E Coli

Enteropathogenic Escherichia coli grow as discrete colonies on the mucous membranes of the small intestine. A similar pattern can be demonstrated in vitro; termed localized adherence (LA), it is characterized by the presence of circumscribed clusters of bacteria attached to the surfaces of cultured epithelial cells. The LA phenotype was studied using B171, an O111:NM enteropathogenic E. coli (EPEC) strain, and HEp-2 cell monolayers. LA could be detected 30-60 min after exposure of HEp-2 cells to B171. However, bacteria transferred from infected HEp-2 cells to fresh monolayers exhibited LA within 15 min, indicating that LA is an inducible phenotype. Induction of the LA phenotype was found to be associated with de novo protein synthesis and changes in the outer membrane proteins, including the production of a new 18.5-kD polypeptide. A partial NH2-terminal amino acid sequence of this polypeptide was obtained and showed it to be identical through residue 12 to the recently described bundle-forming pilus subunit of EPEC. Expression of the 18.5-kD polypeptide required the 57-megadalton enteropathogenic E. coli adherence plasmid previously shown to be required for the LA phenotype in vitro and full virulence in vivo. This observation, the correspondence of the 18.5-kD polypeptide to an EPEC-specific pilus protein, and the temporal correlation of its expression with the development of the LA phenotype suggest that it may contribute to the EPEC colonial mode of growth.

scholarly journals In Vivo Synthesis of the Periplasmic Domain of TonB Inhibits Transport through the FecA and FhuA Iron Siderophore Transporters of Escherichia coli

2001 ◽  
Vol 183 (20) ◽  
pp. 5885-5895 ◽  
Author(s):  
S. Peter Howard ◽  
Christina Herrmann ◽  
Chad W. Stratilo ◽  
V. Braun
Keyword(s):  
Escherichia Coli ◽  
Cytoplasmic Membrane ◽  
Signal Sequence ◽  
Outer Membrane Proteins ◽  
Proton Motive Force ◽  
Motive Force ◽  
In Vivo Studies ◽  
Siderophore Transport

ABSTRACT The siderophore transport activities of the two outer membrane proteins FhuA and FecA of Escherichia coli require the proton motive force of the cytoplasmic membrane. The energy of the proton motive force is postulated to be transduced to the transport proteins by a protein complex that consists of the TonB, ExbB, and ExbD proteins. In the present study, TonB fragments lacking the cytoplasmic membrane anchor were exported to the periplasm by fusing them to the cleavable signal sequence of FecA. Overexpressed TonB(33-239), TonB(103-239), and TonB(122-239) fragments inhibited transport of ferrichrome by FhuA and of ferric citrate by FecA, transcriptional induction of the fecABCDE transport genes by FecA, infection by phage φ80, and killing of cells by colicin M via FhuA. Transport of ferrichrome by FhuAΔ5-160 was also inhibited by TonB(33-239), although FhuAΔ5-160 lacks the TonB box which is involved in TonB binding. The results show that TonB fragments as small as the last 118 amino acids of the protein interfere with the function of wild-type TonB, presumably by competing for binding sites at the transporters or by forming mixed dimers with TonB that are nonfunctional. In addition, the interactions that are inhibited by the TonB fragments must include more than the TonB box, since transport through corkless FhuA was also inhibited. Since the periplasmic TonB fragments cannot assume an energized conformation, these in vivo studies also agree with previous cross-linking and in vitro results, suggesting that neither recognition nor binding to loaded siderophore receptors is the energy-requiring step in the TonB-receptor interactions.

A Review on Recent Researches of Morinda Citrifolia, L. (Noni) as Functional Foods and Medical Herbs

2016 ◽  
Vol 10 (2) ◽  
pp. 172-186
Author(s):  
Agus Sudibyo ◽  
Tiurlan F. Hutajulu
Keyword(s):  
Vitamin A ◽  
Vitamin C ◽  
Biological Effects ◽  
Morinda Citrifolia ◽  
In Vivo Studies ◽  
Cancer Disease ◽  
Potential Health ◽  
Toxicological Assessment

Morinda Citrifolia, L.  known as Noni or Mengkudu is planting belonging to the family of Rubiaceae. A number of major components have been identified in leaves, roots, fruits of Noni plant, such as scopoletin, octanoic acid, vitamin C, iridoid, terpenoids, alkaloids, anthraquinones, beta-sitosterol, carotene, vitamin A, flavone glycosides, alizarin, amino acids, acubin, austin, caproic acid, caprylic acid and putative procyonine. Its use as a botanical dietary supplement has grown tremendously in recent years. The results of epidemiological studies suggest that the Noni consumption may help prevent several chronic diseases, including cancer disease, cardiovascular disease, type 2 diabetes mellitus, heart disease, artherosclerosis, blood vessel problem, gastric ulcer, drug addiction, muscle ached and pein. Several studies have also demonstrated anti-inflammatory, antioxidant, antimicrobial, analgesic, and immunologicalactivity. Based on a toxicological assessment, Noni juice was considered as safe. Although, a large number of in vitro and to a certain extent, and in vivo studies demonstrated a range potentially beneficial effects, clinical information data are still lacking completely. Therefore, to what extent the information findings from experimental pharmacological studies is not complete at present, so this article reviews potential health benefits for consumptions, its biological effects and looking for a new informationthat needs to be explored in detail before a recommendation can be madeABSTRAKMorinda citrofolia, L (mengkudu) merupakan jenis tanaman yang termasuk dalam golongan Rubiaceadan buahnya dikenal dengan nama Noni atau mengkudu. Beberapa komponen utama dalam tanaman tersebut telah diidentifikasi, mulai dari bagian akar, daun, dan buah, seperti kandungan scopoletin, asam oktanoad, vitamin C, iridoid, terpenoid, alkaloid, anthraquinon, beta-sitosterol, karotene, vitamin A, flavon glikosida, alizarin, asam amino, acubin, austin, asam kaproat, asam kaprilat dan putativ prokseronin. Buah tersebut akhir-akhir ini telah sukses banyak dimanfaatkan sebagai diet suplemen. Hasil studi secara epidemiologi menyatakan bahwa konsumsi mengkudu dapat membantu mencegah beberapa penyakit kronis, seperti penyakit kanker, kardiovaskular, diabetes tipe 2, penyakit jantung, artherosklerosis, masalah pembuluh darah, pencernaan, dan sakit otot. Beberapa studi juga menunjukkan bahwa mengkudu dapat berfungsi sebagai anti inflamasi, antioksidan, antimikroba, analgesik, dan bersifat immunlogis.Berdasarkan kajian secara toksikologi, buah dan jus mengkudu dinyatakan aman untuk dikonsumsi.  Penelitian secara in vitro pada beberapa jenis penyakit tertentu sedang diperluas, dan penelitian secara in vivo menunjukkan bahwa mengkudu mempunyai rentang potensi pengaruh yang baik bagi kesehatan, meskipun data informasinya secara klinis kurang lengkap. Oleh karena itu, untuk mengetahui apa yang sudah ditemukan dari hasil penelitian secara farmalogis yang belum lengkapsaat ini, maka dalam tulisan ini membahas potensi keuntungan kesehatan bila dikonsumsi, pengaruh biologinya dan pencarian informasibaru yang  perlu dikaji lebih rinci sebelum rekomendasi ditetapkan.Kata kunci: Mengkudu (Morinda citrifolia, L), pangan fungsional, rempah medis. 

A Multicenter Phase II Study of Combination Treatment with Melphalan, Arsenic Trioxide and Vitamin C (MAC) for Patients with Relapsed or Refractory Multiple Myeloma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2564-2564 ◽  
Author(s):  
James Berenson ◽  
Ralph Boccia ◽  
David Siegel ◽  
Marek Bozdech ◽  
Alberto Bessudo ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Ascorbic Acid ◽  
Vitamin C ◽  
Arsenic Trioxide ◽  
Phase Ii ◽  
Stable Disease ◽  
Objective Response ◽  
In Vivo Studies

Abstract Background: Despite the recent increase in treatment options for patients with multiple myeloma (MM), the disease remains largely incurable. Both arsenic trioxide (ATO) and melphalan have shown clinical activity in MM. Recent in vitro and in vivo studies in our laboratory have shown that arsenic trioxide sensitizes chemoresistant MM cells to melphalan-induced cytotoxicity; the addition of ascorbic acid (AA) further improves this effect. We conducted a multi-center clinical trial to evaluate the safety and efficacy of this steroid-free combination, melphalan, ATO and vitamin C (MAC), for patients with relapsed/refractory MM. Methods: MM pts who relapsed after responding to 1st-line therapy and/or were refractory to prior treatment were enrolled. During week 1 of each 6-week cycle, pts received ATO, 0.25 mg/kg IV, followed by ascorbic acid (AA), 1 g IV, days 1–4. ATO followed by AA was given twice-weekly for the next 4 weeks of each cycle. Low-dose melphalan (0.10 mg/kg) was administered orally for the first 4 days of each cycle. Pts received a maximum of 6 cycles followed by weekly maintenance treatment with ATO and AA. The primary objectives of this study were to determine response rate and safety and tolerability of MAC therapy. Results: 65 patients have been enrolled and 51 are currently evaluable for response. 26 (1 CR, 10 PR, 15 MR) of the 51 evaluable patients (51%) had an objective response and an additional 14 patients achieved stable disease, resulting in a total of 40 patients (78%) with disease control. Among patients with elevated serum creatinine levels at baseline, renal function improved for those with responsive or stable disease. 20 of the 26 responding patients had failed ≥ 2 prior therapies: 19 pts had received prior thalidomide or lenalidomide therapy and 8 pts had received prior bortezomib. The regimen was well-tolerated with few significant side effects reported. Mild cytopenias occurred infrequently and were reversible. Conclusions: The results from this large multi-center phase II trial show that the MAC regimen is active in a group of MM patients who had either relapsed or were refractory to standard and/or investigational MM treatments. The regimen was well-tolerated even in this heavily pre-treated patient population. These findings are consistent with preclinical studies that showed the efficacy of this combination from both in vitro and in vivo studies.

scholarly journals Modelling of Infection by Enteropathogenic Escherichia coli Strains in Lineages 2 and 4 Ex Vivo and In Vivo by Using Citrobacter rodentium Expressing TccP

2009 ◽  
Vol 77 (4) ◽  
pp. 1304-1314 ◽  
Author(s):  
Francis Girard ◽  
Valérie F. Crepin ◽  
Gad Frankel
Keyword(s):  
Escherichia Coli ◽  
Actin Polymerization ◽  
Ex Vivo ◽  
In Vivo Studies ◽  
Citrobacter Rodentium ◽  
T3ss Effector ◽  
Gut Mucosa ◽  
Colonization Dynamics

ABSTRACT Enteropathogenic Escherichia coli (EPEC) strains colonize the human gut mucosa via attaching-and-effacing (A/E) lesion formation, while in vitro they employ diverse strategies to trigger actin polymerization. Strains belonging to the EPEC-1 lineage trigger strong actin polymerization via tyrosine phosphorylation of the type III secretion system (T3SS) effector Tir, recruitment of Nck, and activation of N-WASP. Strains belonging to EPEC-2 and EPEC-4 can trigger strong actin polymerization by dual mechanisms, since while employing the Tir-Nck pathway they can additionally activate N-WASP via the T3SS effectors TccP2 and TccP, respectively. It is currently not known if the ability to trigger actin polymerization by twin mechanisms increases in vivo virulence or fitness. Since mice are resistant to EPEC infection, in vivo studies are frequently done using the murine model pathogen Citrobacter rodentium, which shares with EPEC-1 strains the ability to induce A/E lesions and trigger strong actin polymerization via the Tir:Nck pathway. In order to model infections with EPEC-2 and EPEC-4, we constructed C. rodentium strains expressing TccP. Using a mouse intestinal in vitro organ culture model and oral gavage into C57BL/6 mice, we have shown that TccP can cooperate with Tir of C. rodentium. The recombinant strains induced typical A/E lesions ex vivo and in vivo. Expression of TccP did not alter C. rodentium colonization dynamics or pathology. In competition with the wild-type strain, expression of TccP in C. rodentium did not confer a competitive advantage.

scholarly journals Dra/AfaE Adhesin of Uropathogenic Dr/Afa+Escherichia coli Mediates Mortality in Pregnant Rats

2005 ◽  
Vol 73 (11) ◽  
pp. 7597-7601 ◽  
Author(s):  
K. Wroblewska-Seniuk ◽  
R. Selvarangan ◽  
A. Hart ◽  
R. Pladzyk ◽  
P. Goluszko ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Maternal Mortality ◽  
Double Mutant ◽  
Lethal Effect ◽  
In Vivo Studies ◽  
Sprague Dawley ◽  
Pregnant Rats ◽  
E Coli

ABSTRACT Escherichia coli bearing adhesins of the Dr/Afa family frequently causes urogenital infections during pregnancy in humans and has been associated with mortality in pregnant rats. Two components of the adhesin, Dra/AfaE and Dra/AfaD, considered virulence factors, are responsible for bacterial binding and internalization. We hypothesize that gestational mortality caused by Dr/Afa+ E. coli is mediated by one of these two proteins, Dra/AfaE or Dra/AfaD. In this study, using afaE and/or afaD mutants, we investigated the role of the afaE and afaD genes in the mortality of pregnant rats from intrauterine infection. Sprague-Dawley rats, on the 17th day of pregnancy, were infected with the E. coli afaE + afaD and afaE afaD + mutants. The clinical E. coli strain (afaE + afaD +) and the afaE afaD double mutant were used as positive and negative controls, respectively. The mortality rate was evaluated 24 h after infection. The highest maternal mortality was observed in the group infected with the afaE + afaD + strain, followed by the group infected with the afaE + afaD strain. The mortality was dose dependent. The afaE afaD double mutant did not cause maternal mortality, even with the highest infection dose. The in vivo studies corresponded with the invasion assay, where the afaE + strains were the most invasive (afaE + afaD strain > afaE + afaD + strain), while the afaE mutant strains (afaE afaD + and afaE afaD strains) seemed to be noninvasive. This study shows for the first time that the afaE gene coding for the AfaE subunit of Dr/Afa adhesin is involved in the lethal outcome of gestational infection in rats. This lethal effect associated with AfaE correlates with the invasiveness of afaE + E. coli strains in vitro.

3-O-methylglucose transport in soleus muscle of bacteremic rats

1987 ◽  
Vol 253 (1) ◽  
pp. R55-R63
Author(s):  
M. V. Westfall ◽  
M. M. Sayeed
Keyword(s):  
Escherichia Coli ◽  
Soleus Muscle ◽  
Rate Coefficient ◽  
In Vitro Studies ◽  
In Vivo Studies ◽  
Membrane Function ◽  
Fasted Rats ◽  
Stimulation Of

Basal and insulin-stimulated soleus muscle 3-O-[14C]methylglucose ([14C]-3-O-MG) transport was studied in vitro and in vivo during bacteremia in rats. Fasted rats were injected with Escherichia coli to produce bacteremia (B), and controls (C) received saline. In vitro studies using soleus muscles were carried out 8 or 12 h after bacterial injection, and transport was measured using the rate coefficient (lambda = min-1). Although insulin-stimulated (10 mU/ml) [14C]-3-O-MG transport was decreased in 12-h bacteremic rat muscles (lambda B = 0.041 +/- 0.003; lambda C = 0.055 +/- 0.002), the basal [14C]-3-O-MG transport rate coefficient was elevated (lambda B = 0.027 +/- 0.004; lambda C = 0.019 +/- 0.001). For in vivo studies, [14C]-3-O-MG with or without insulin was injected into rats 10-40 min prior to removing soleus muscles at 12 h postbacterial or postsaline injection. Transport was measured as the ratio of [14C]-3-O-MGintracell/[14C]-3-O-MGextracell. Basal ratios were not different and muscles from both control and bacteremic rats responded comparably to insulin with increased [14C]-3-O-MG transport during the initial 30 min. At 35-40 min postinsulin injection there was a further stimulation of [14C]-3-O-MG transport in control but not in 12-h bacteremic rat muscles. The changes in [14C]-3-O-MG transport observed in vitro and in vivo after 12 h of bacteremia may be due to circulating mediators and/or changes in membrane function.

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