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Parak M, Asgari A, Hasani Nourian Y, Ghanei M. A review of poisoning with various types of biotoxins and its common clinical symptoms. Toxicon 2024; 240:107629. [PMID: 38336277 DOI: 10.1016/j.toxicon.2024.107629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 01/01/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024]
Abstract
INTRODUCTION Biotoxins are toxic substances that originate from living organisms and are harmful to humans. Therefore, we need to know the symptoms of biotoxins poisoning to manage the damage. The purpose of this study is to establish a practical diagnostic protocol for dealing with poisoned patients exposed to biotoxins. MATERIALS AND METHODS The present study is a review study. Our studied community is articles and books matching the title of the project and relevant keywords. First, by searching the key words sign, symptom, biotoxins, relevant articles were extracted and studied from valid databases. By reviewing the studies based on the search strategy, four groups of biotoxins that were studied the most were identified. These four groups are marine biotoxins, bacterial biotoxins, fungal biotoxins and plant biotoxins. In each of these biotoxin groups, important toxins were selected and studied. RESULTS A total of 1864 articles were initially identified from the databases searched in present study. After screening titles and abstracts, 26 articles were included in the systematic review. Specifically, 7 articles were included for bacterial toxins, 9 articles for marine toxins, 5 articles for plant toxins and 5 articles for fungal toxins. CONCLUSION The symptoms of plant biotoxins poisoning may include cardiovascular, hematologic, neurologic, respiratory, renal, and gastrointestinal symptoms, while the symptoms of fungal biotoxins poisoning may include hepatic, renal, gastrointestinal, musculoskeletal, metabolic, respiratory, neurological, and cardiovascular symptoms. marine biotoxins poisoning presents with gastrointestinal and neurological symptoms, with varying incubation periods and recovery times. bacterial biotoxins exposure can lead to a wide range of clinical symptoms, with diarrhea, vomiting, and abdominal pain being the most common, and hemoglobinuria or hematuria being a sensitive and specific clinical manifestation for diagnosing ongoing HUS in children.
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Affiliation(s)
- Mohammadreza Parak
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
| | - Alireza Asgari
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
| | - Yazdan Hasani Nourian
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
| | - Mostafa Ghanei
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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Ferreira G, Cardozo R, Sastre S, Costa C, Santander A, Chavarría L, Guizzo V, Puglisi J, Nicolson GL. Bacterial toxins and heart function: heat-labile Escherichia coli enterotoxin B promotes changes in cardiac function with possible relevance for sudden cardiac death. Biophys Rev 2023; 15:447-473. [PMID: 37681088 PMCID: PMC10480140 DOI: 10.1007/s12551-023-01100-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 07/11/2023] [Indexed: 09/09/2023] Open
Abstract
Bacterial toxins can cause cardiomyopathy, though it is not its most common cause. Some bacterial toxins can form pores in the membrane of cardiomyocytes, while others can bind to membrane receptors. Enterotoxigenic E. coli can secrete enterotoxins, including heat-resistant (ST) or labile (LT) enterotoxins. LT is an AB5-type toxin that can bind to specific cell receptors and disrupt essential host functions, causing several common conditions, such as certain diarrhea. The pentameric B subunit of LT, without A subunit (LTB), binds specifically to certain plasma membrane ganglioside receptors, found in lipid rafts of cardiomyocytes. Isolated guinea pig hearts and cardiomyocytes were exposed to different concentrations of purified LTB. In isolated hearts, mechanical and electrical alternans and an increment of heart rate variability, with an IC50 of ~0.2 μg/ml LTB, were observed. In isolated cardiomyocytes, LTB promoted significant decreases in the amplitude and the duration of action potentials. Na+ currents were inhibited whereas L-type Ca2+ currents were augmented at their peak and their fast inactivation was promoted. Delayed rectifier K+ currents decreased. Measurements of basal Ca2+ or Ca2+ release events in cells exposed to LTB suggest that LTB impairs Ca2+ homeostasis. Impaired calcium homeostasis is linked to sudden cardiac death. The results are consistent with the recent view that the B subunit is not merely a carrier of the A subunit, having a role explaining sudden cardiac death in children (SIDS) infected with enterotoxigenic E. coli, explaining several epidemiological findings that establish a strong relationship between SIDS and ETEC E. coli. Supplementary Information The online version contains supplementary material available at 10.1007/s12551-023-01100-6.
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Affiliation(s)
- Gonzalo Ferreira
- Ion Channels, Biological Membranes and Cell Signaling Laboratory, Dept. Of Biophysics, Facultad de Medicina, Universidad de la Republica, Gral Flores 2125, 11800 Montevideo, CP Uruguay
| | - Romina Cardozo
- Ion Channels, Biological Membranes and Cell Signaling Laboratory, Dept. Of Biophysics, Facultad de Medicina, Universidad de la Republica, Gral Flores 2125, 11800 Montevideo, CP Uruguay
| | - Santiago Sastre
- Ion Channels, Biological Membranes and Cell Signaling Laboratory, Dept. Of Biophysics and Centro de Investigaciones Biomédicas (CeInBio), Facultad de Medicina, Universidad de la Republica, Gral Flores 2125, 11800 Montevideo, CP Uruguay
| | - Carlos Costa
- Ion Channels, Biological Membranes and Cell Signaling Laboratory, Dept. Of Biophysics, Facultad de Medicina, Universidad de la Republica, Gral Flores 2125, 11800 Montevideo, CP Uruguay
| | - Axel Santander
- Ion Channels, Biological Membranes and Cell Signaling Laboratory, Dept. Of Biophysics, Facultad de Medicina, Universidad de la Republica, Gral Flores 2125, 11800 Montevideo, CP Uruguay
| | - Luisina Chavarría
- Ion Channels, Biological Membranes and Cell Signaling Laboratory, Dept. Of Biophysics, Facultad de Medicina, Universidad de la Republica, Gral Flores 2125, 11800 Montevideo, CP Uruguay
| | - Valentina Guizzo
- Ion Channels, Biological Membranes and Cell Signaling Laboratory, Dept. Of Biophysics, Facultad de Medicina, Universidad de la Republica, Gral Flores 2125, 11800 Montevideo, CP Uruguay
| | - José Puglisi
- College of Medicine, California North State University, 9700 West Taron Drive, Elk Grove, CA 95757 USA
| | - G. L. Nicolson
- Institute for Molecular Medicine, Beach, Huntington, CA USA
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Paul Keila L, Dongmo Yan M, Kouipou Ru T, Fred D, Darline D, Boyom Fabr F. Antibacterial and Cytotoxic Activities of Three Medicinal Plants from Cameroon (Alstonia boonei, Cassia alata and Garcinia lucida) Against Diarrhea. ACTA ACUST UNITED AC 2020. [DOI: 10.3923/rjmp.2020.53.63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Hu P, Zhao F, Zhu W, Wang J. Effects of early-life lactoferrin intervention on growth performance, small intestinal function and gut microbiota in suckling piglets. Food Funct 2019; 10:5361-5373. [PMID: 31393487 DOI: 10.1039/c9fo00676a] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The early postnatal stage is a critical period for suckling animals in developing intestinal function and stabilizing gut microbiota. Lactoferrin (LF) plays a critical role in promoting gut development and regulating gut microbiota. This study investigates the impact of early-life lactoferrin (LF) intervention on the growth performance, small intestinal function and gut microbiota in suckling piglets. Sixty suckling piglets (1.51 ± 0.05 kg) obtained from six sows (10 piglets per litter) were assigned to a control (CON) group and an LF group in each litter, which were sow-fed. Piglets in the LF group were orally administered 8-12 mL LF solution (0.5 g per kg body weight per day) for a week, and piglets in the CON group were orally administered the same dose of physiological saline. Six piglets (n = 6) from each group were euthanized on days 8 and 21. The early-life LF intervention increased growth performance, with higher villi height of the jejunum and greater disaccharidase activity of the jejunum and ileum (P < 0.05). Diarrhoea incidence decreased in the LF group from day 1 to day 7 (P < 0.05). Urinary lactulose-mannitol ratios decreased in the LF group, whereas the gene and protein expressions of jejunal occludin increased in the LF group on day 8 and day 21, and higher gene and protein levels of ileal occludin were observed on day 8 (P < 0.05). Additionally, the LF piglets had lower concentrations of IL-1β and TNF-α, and higher concentration of IL-10 in the jejunum (P < 0.05). For the ileum, higher concentration of IL-10 and lower concentration of TNF-α were observed in the LF group (P < 0.05). LF piglets had a greater abundance of Lactobacillus and lower abundance of Veillonella and Escherichia-Shigella in the jejunum on day 8 (P < 0.05). In the ileum, the abundance of Actinobacillus was decreased in the LF piglets on day 8 and day 21 (P < 0.05). The early-life LF intervention enhanced the growth performance and decreased diarrhoea incidence in the suckling piglets by promoting the development of intestinal function and changing the microbiota in the small intestine.
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Affiliation(s)
- Ping Hu
- National Center for International Research on Animal Gut Nutrition, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, National Experimental Teaching Demonstration Center of Animal Science, College of Animal Science and Technology, Nanjing Agricultural University, Jiangsu Province 210095, P. R. China. and Laboratory of Gastrointestinal Microbiology, Xiaolingwei Street, Weigang 1, Nanjing 210095, China
| | - Fangzhou Zhao
- National Center for International Research on Animal Gut Nutrition, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, National Experimental Teaching Demonstration Center of Animal Science, College of Animal Science and Technology, Nanjing Agricultural University, Jiangsu Province 210095, P. R. China. and Laboratory of Gastrointestinal Microbiology, Xiaolingwei Street, Weigang 1, Nanjing 210095, China
| | - Weiyun Zhu
- National Center for International Research on Animal Gut Nutrition, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, National Experimental Teaching Demonstration Center of Animal Science, College of Animal Science and Technology, Nanjing Agricultural University, Jiangsu Province 210095, P. R. China. and Laboratory of Gastrointestinal Microbiology, Xiaolingwei Street, Weigang 1, Nanjing 210095, China
| | - Jing Wang
- National Center for International Research on Animal Gut Nutrition, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, National Experimental Teaching Demonstration Center of Animal Science, College of Animal Science and Technology, Nanjing Agricultural University, Jiangsu Province 210095, P. R. China. and Laboratory of Gastrointestinal Microbiology, Xiaolingwei Street, Weigang 1, Nanjing 210095, China
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Raimi AR, Ezeokoli OT, Adeleke RA. High-throughput sequence analysis of bacterial communities in commercial biofertiliser products marketed in South Africa: an independent snapshot quality assessment. 3 Biotech 2019; 9:108. [PMID: 30863692 DOI: 10.1007/s13205-019-1643-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 02/20/2019] [Indexed: 02/03/2023] Open
Abstract
The genetic and predicted functional diversity of bacterial communities in 12 commercial biofertiliser products were evaluated using high-throughput sequencing of the 16S rRNA gene. Proteobacteria, Firmicutes and Bacteroides dominated the bacterial communities, with the genera Pseudomonas, Lactobacillus, Bacillus, Bradyrhizobium and Rhizobium being prevalent. The manufacturer-specified species were detected in relatively high abundance in two of the products while a few or none of the specified species were detected in some products. A number of unspecified microbes were detected, including potential human and crop pathogens such as Alcaligenes, Clostridium, Escherichia-Shigella and Proteus. The functional prediction unravelled high prevalence of enzyme-coding genes such as nitrogenase, NifT, alkaline phosphatase and reductases of nitric oxide, nitrate and nitrite which contribute to nitrogen-fixation, phosphorus solubilisation and degradation of nitrates and nitrites. In addition, toxins such as leukocidin/hemolysin and colicin V protein that cause product quality damage were highly predicted in over 67% of the products. Overall, high-throughput sequence analysis of bacterial communities in biofertiliser products revealed that majority of the products were of poor quality. This result justifies the need for regular quality assessment and improvement in quality control systems during biofertiliser formulation.
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Wang D, Sun F, Li Z, Hu Y, Xu R. Acute septic arthritis of shoulder joint caused by Aeromonas veronii biotype sobria. DER ORTHOPADE 2018; 47:1027-1031. [PMID: 29872872 DOI: 10.1007/s00132-018-3585-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We present the case of a 91-year-old woman who presented with a 2‑day history of progressive pain and immobility of the right shoulder joint after fever of unknown etiology. Aeromonas sobria was isolated from a culture of purulent synovial fluid. The clinical condition gradually improved with the application of appropriate antibiotics and no surgical intervention was necessary. This report indicates that acute septic arthritis may result from Aeromonas veronii biotype sobria infections in healthy people. This case is contrary to the previous reports due to the absence of obvious risk factors.
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Affiliation(s)
- Dexin Wang
- Department of Orthopaedics, Mingzhou Hospital of Zhejiang University, 168 Taian West Road, Ningbo, Zhejiang Province, China
| | - Fanggui Sun
- Department of Orthopaedics, Mingzhou Hospital of Zhejiang University, 168 Taian West Road, Ningbo, Zhejiang Province, China
| | - Zheng Li
- Department of Orthopaedics, Mingzhou Hospital of Zhejiang University, 168 Taian West Road, Ningbo, Zhejiang Province, China
| | - Yutong Hu
- Department of Orthopaedics, Mingzhou Hospital of Zhejiang University, 168 Taian West Road, Ningbo, Zhejiang Province, China
| | - Rongming Xu
- Department of Orthopaedics, Mingzhou Hospital of Zhejiang University, 168 Taian West Road, Ningbo, Zhejiang Province, China.
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Allaire JM, Morampudi V, Crowley SM, Stahl M, Yu H, Bhullar K, Knodler LA, Bressler B, Jacobson K, Vallance BA. Frontline defenders: goblet cell mediators dictate host-microbe interactions in the intestinal tract during health and disease. Am J Physiol Gastrointest Liver Physiol 2018; 314:G360-G377. [PMID: 29122749 PMCID: PMC5899238 DOI: 10.1152/ajpgi.00181.2017] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Goblet cells (GCs) are the predominant secretory epithelial cells lining the luminal surface of the mammalian gastrointestinal (GI) tract. Best known for their apical release of mucin 2 (Muc2), which is critical for the formation of the intestinal mucus barrier, GCs have often been overlooked for their active contributions to intestinal protection and host defense. In part, this oversight reflects the limited tools available to study their function but also because GCs have long been viewed as relatively passive players in promoting intestinal homeostasis and host defense. In light of recent studies, this perspective has shifted, as current evidence suggests that Muc2 as well as other GC mediators are actively released into the lumen to defend the host when the GI tract is challenged by noxious stimuli. The ability of GCs to sense and respond to danger signals, such as bacterial pathogens, has recently been linked to inflammasome signaling, potentially intrinsic to the GCs themselves. Moreover, further work suggests that GCs release Muc2, as well as other mediators, to modulate the composition of the gut microbiome, leading to both the expansion as well as the depletion of specific gut microbes. This review will focus on the mechanisms by which GCs actively defend the host from noxious stimuli, as well as describe advanced technologies and new approaches by which their responses can be addressed. Taken together, we will highlight current insights into this understudied, yet critical, aspect of intestinal mucosal protection and its role in promoting gut defense and homeostasis.
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Affiliation(s)
- Joannie M. Allaire
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vijay Morampudi
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shauna M. Crowley
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin Stahl
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hongbing Yu
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kirandeep Bhullar
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Leigh A. Knodler
- 2Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, Washington
| | - Brian Bressler
- 3Division of Gastroenterology, Department of Medicine, St. Paul’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kevan Jacobson
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bruce A. Vallance
- 1Division of Gastroenterology, Department of Pediatrics, BC Children’s Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Huang C, Song P, Fan P, Hou C, Thacker P, Ma X. Dietary Sodium Butyrate Decreases Postweaning Diarrhea by Modulating Intestinal Permeability and Changing the Bacterial Communities in Weaned Piglets. J Nutr 2015; 145:2774-80. [PMID: 26491121 DOI: 10.3945/jn.115.217406] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 09/29/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The vast majority of substances used as alternatives to antibiotics produce inconsistent results and rarely equal the effectiveness of in-feed antibiotics. OBJECTIVE This study evaluated the effects of the combined use of sodium butyrate (SB) and reduced antibiotics in a piglet diet in promoting performance and to control weaning diarrhea. METHODS Piglets weaned at 28 d were randomly assigned to a corn-soybean meal control ration [negative control (NC)]; a similar ration with 50 mg kitasamycin/kg, 20 mg colistin sulfate/kg, and 1000 mg encapsulated SB/kg [reduced antibiotics + SB (ASB)]; or to a ration with 100 mg kitasamycin/kg and 40 mg colistin sulfate/kg [positive control (PC)] for 28 d. Performance, diarrhea incidence, intestinal permeability, and changes in the bacterial communities in the ileum and colon were determined. RESULTS Weight gain and the ratio of weight gain to feed intake were significantly greater in the ASB and PC piglets than in the NC piglets (P < 0.05). Diarrhea incidence was lower in the ASB and PC piglets than in the NC piglets (P < 0.05). Urinary lactulose to mannitol ratios were 25% and 30% lower, respectively, whereas jejunal and colonic occludin protein expressions were significantly greater in the ASB and PC piglets compared with the NC piglets (P < 0.05). In the intestinal mucosa, malondialdehyde was lower in the ASB and PC piglets (by 42% and 43%, respectively), whereas tumor necrosis factor α (TNF-α) was 63% lower in the ASB piglets and 59% lower in the PC piglets compared with the NC piglets (P < 0.05). 16S ribosomal RNA gene sequence analysis revealed a higher colonic Shannon index and a lower colonic Simpson index in the ASB and PC piglets than in the NC piglets. In addition, the ASB and PC treatments caused a striking decrease in Lactobacillaceae and a noticeable increase in Clostridiaceae in the ileal and colonic lumen, as well as increases in Ruminococcaceae, Lachnospiraceae, and Bacteroidetes in the colonic lumen. CONCLUSION Collectively, our results support an important role for SB in improving performance and decreasing diarrhea incidence in weaned piglets by modulation of intestinal permeability and the bacterial communities in the ileum and colon.
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Affiliation(s)
- Chang Huang
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China
| | - Peixia Song
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China
| | - Peixin Fan
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China
| | - Chengli Hou
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China
| | - Phil Thacker
- Department of Animal and Poultry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; and
| | - Xi Ma
- State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, China; Department of Internal Medicine, Center for Autophagy Research, University of Texas Southwestern Medical Center, Dallas, TX
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Nichols JM, Maiellaro I, Abi-Jaoude J, Curci S, Hofer AM. "Store-operated" cAMP signaling contributes to Ca2+-activated Cl- secretion in T84 colonic cells. Am J Physiol Gastrointest Liver Physiol 2015; 309:G670-9. [PMID: 26316590 PMCID: PMC4609931 DOI: 10.1152/ajpgi.00214.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/21/2015] [Indexed: 01/31/2023]
Abstract
Apical cAMP-dependent CFTR Cl(-) channels are essential for efficient vectorial movement of ions and fluid into the lumen of the colon. It is well known that Ca(2+)-mobilizing agonists also stimulate colonic anion secretion. However, CFTR is apparently not activated directly by Ca(2+), and the existence of apical Ca(2+)-dependent Cl(-) channels in the native colonic epithelium is controversial, leaving the identity of the Ca(2+)-activated component unresolved. We recently showed that decreasing free Ca(2+) concentration ([Ca(2+)]) within the endoplasmic reticulum (ER) lumen elicits a rise in intracellular cAMP. This process, which we termed "store-operated cAMP signaling" (SOcAMPS), requires the luminal ER Ca(2+) sensor STIM1 and does not depend on changes in cytosolic Ca(2+). Here we assessed the degree to which SOcAMPS participates in Ca(2+)-activated Cl(-) transport as measured by transepithelial short-circuit current (Isc) in polarized T84 monolayers in parallel with imaging of cAMP and PKA activity using fluorescence resonance energy transfer (FRET)-based reporters in single cells. In Ca(2+)-free conditions, the Ca(2+)-releasing agonist carbachol and Ca(2+) ionophore increased Isc, cAMP, and PKA activity. These responses persisted in cells loaded with the Ca(2+) chelator BAPTA-AM. The effect on Isc was enhanced in the presence of the phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (IBMX), inhibited by the CFTR inhibitor CFTRinh-172 and the PKA inhibitor H-89, and unaffected by Ba(2+) or flufenamic acid. We propose that a discrete component of the "Ca(2+)-dependent" secretory activity in the colon derives from cAMP generated through SOcAMPS. This alternative mode of cAMP production could contribute to the actions of diverse xenobiotic agents that disrupt ER Ca(2+) homeostasis, leading to diarrhea.
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Affiliation(s)
- Jonathan M. Nichols
- Department of Veterans Affairs Boston Healthcare System and Department of Surgery, Brigham & Women's Hospital and Harvard Medical School, West Roxbury, Massachusetts
| | - Isabella Maiellaro
- Department of Veterans Affairs Boston Healthcare System and Department of Surgery, Brigham & Women's Hospital and Harvard Medical School, West Roxbury, Massachusetts
| | - Joanne Abi-Jaoude
- Department of Veterans Affairs Boston Healthcare System and Department of Surgery, Brigham & Women's Hospital and Harvard Medical School, West Roxbury, Massachusetts
| | - Silvana Curci
- Department of Veterans Affairs Boston Healthcare System and Department of Surgery, Brigham & Women's Hospital and Harvard Medical School, West Roxbury, Massachusetts
| | - Aldebaran M. Hofer
- Department of Veterans Affairs Boston Healthcare System and Department of Surgery, Brigham & Women's Hospital and Harvard Medical School, West Roxbury, Massachusetts
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Spadaro S, Berselli A, Marangoni E, Romanello A, Colamussi MV, Ragazzi R, Zardi S, Volta CA. Aeromonas sobria necrotizing fasciitis and sepsis in an immunocompromised patient: a case report and review of the literature. J Med Case Rep 2014; 8:315. [PMID: 25245365 PMCID: PMC4177370 DOI: 10.1186/1752-1947-8-315] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 07/24/2014] [Indexed: 11/24/2022] Open
Abstract
Introduction Aeromonas veronii biovar sobria is a rare cause of bacteremia, with several studies indicating that this isolate may be of particular clinical significance since it is enterotoxin producing. A wide spectrum of infections has been associated with Aeromonas species in developing countries that include gastroenteritis, wound infections, septicemia and lung infections. This infection, caused by Aeromonas species, is usually more severe in immunocompromised than immunocompetent individuals. We here describe a case of soft tissue infection and severe sepsis due to Aeromonas sobria in an immunocompromised patient. Case presentation A 74-year-old Caucasian man with a clinical history of chronic lymphocytic leukemia and immune thrombocytopenia, periodically treated with steroids, was admitted to our Intensive Care Unit because of necrotizing fasciitis and multiorgan failure due to Aeromonas sobria, which resulted in his death. The unfortunate coexistence of a Candida albicans infection played a key role in the clinical course. Conclusion Our experience suggests that early recognition and aggressive medical and surgical therapy are determinants in the treatment of severe septicemia caused by an Aeromonas sobria in an immunocompromised patient.
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Affiliation(s)
- Savino Spadaro
- Department of Morphology, Surgery and Experimental Medicine, Sant' Anna Hospital, University of Ferrara, Via Aldo Moro 8, Ferrara, FE 44124, Italy.
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Ghosh AR. Appraisal of microbial evolution to commensalism and pathogenicity in humans. CLINICAL MEDICINE INSIGHTS. GASTROENTEROLOGY 2013; 6:1-12. [PMID: 24833938 PMCID: PMC4020404 DOI: 10.4137/cgast.s11858] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The human body is host to a number of microbes occurring in various forms of host-microbe associations, such as commensals, mutualists, pathogens and opportunistic symbionts. While this association with microbes in certain cases is beneficial to the host, in many other cases it seems to offer no evident benefit or motive. The emergence and re-emergence of newer varieties of infectious diseases with causative agents being strains that were once living in the human system makes it necessary to study the environment and the dynamics under which this host microbe relationship thrives. The present discussion examines this interaction while tracing the origins of this association, and attempts to hypothesize a possible framework of selective pressures that could have lead microbes to inhabit mammalian host systems.
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Affiliation(s)
- Asit Ranjan Ghosh
- Centre for Infectious Diseases and Control, Division of Medical Biotechnology, School of Biosciences and Technology, VIT University, India
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Molecular Characterization and Virulence Genes of Aeromonas hydrophila Isolated from the Chinese Giant Salamander ( Andrias davidianus). ASIAN HERPETOL RES 2013. [DOI: 10.3724/sp.j.1245.2012.00303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Shniffer A, Visschedyk DD, Ravulapalli R, Suarez G, Turgeon ZJ, Petrie AA, Chopra AK, Merrill AR. Characterization of an actin-targeting ADP-ribosyltransferase from Aeromonas hydrophila. J Biol Chem 2012; 287:37030-41. [PMID: 22969084 DOI: 10.1074/jbc.m112.397612] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The mono-ADP-ribosyltransferase (mART) toxins are contributing factors to a number of human diseases, including cholera, diphtheria, traveler's diarrhea, and whooping cough. VahC is a cytotoxic, actin-targeting mART from Aeromonas hydrophila PPD134/91. This bacterium is implicated primarily in diseases among freshwater fish species but also contributes to gastrointestinal and extraintestinal infections in humans. VahC was shown to ADP-ribosylate Arg-177 of actin, and the kinetic parameters were K(m)(NAD(+)) = 6 μM, K(m)(actin) = 24 μM, and k(cat) = 22 s(-1). VahC activity caused depolymerization of actin filaments, which induced caspase-mediated apoptosis in HeLa Tet-Off cells. Alanine-scanning mutagenesis of predicted catalytic residues showed the predicted loss of in vitro mART activity and cytotoxicity. Bioinformatic and kinetic analysis also identified three residues in the active site loop that were critical for the catalytic mechanism. A 1.9 Å crystal structure supported the proposed roles of these residues and their conserved nature among toxin homologues. Several small molecules were characterized as inhibitors of in vitro VahC mART activity and suramin was the best inhibitor (IC(50) = 20 μM). Inhibitor activity was also characterized against two other actin-targeting mART toxins. Notably, these inhibitors represent the first report of broad spectrum inhibition of actin-targeting mART toxins.
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Affiliation(s)
- Adin Shniffer
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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14
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Scaldaferri F, Pizzoferrato M, Pecere S, Forte F, Gasbarrini A. Bacterial flora as a cause or treatment of chronic diarrhea. Gastroenterol Clin North Am 2012; 41:581-602. [PMID: 22917165 DOI: 10.1016/j.gtc.2012.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Intestinal microflora can be considered an organ of the body. It has several functions in the human gut, mostly metabolic and immunologic, and constantly interacts with the intestinal mucosa in a delicate equilibrium. Chronic diarrhea is associated with an alteration of gut microbiota when a pathogen invades the gut and also in several conditions associated with intestinal mucosal damage or bowel dysfunction, as in inflammatory bowel disease, irritable bowel syndrome, or small bowel bacterial overgrowth. This article discusses the basis of gut microbiota modulation. Evidence for the efficacy of gut microbiota modulation in chronic conditions is also discussed.
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Affiliation(s)
- Franco Scaldaferri
- Division of Internal Medicine and Gastroenterology, Policlinico A. Gemelli Hospital - Catholic University of Rome, Rome, Italy
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15
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Munera D, Martinez E, Varyukhina S, Mahajan A, Ayala-Sanmartin J, Frankel G. Recruitment and membrane interactions of host cell proteins during attachment of enteropathogenic and enterohaemorrhagic Escherichia coli. Biochem J 2012; 445:383-92. [PMID: 22587461 PMCID: PMC4568301 DOI: 10.1042/bj20120533] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
EPEC (enteropathogenic Escherichia coli) and EHEC (enterohaemorrhagic Escherichia coli) are attaching and effacing pathogens frequently associated with infectious diarrhoea. EPEC and EHEC use a T3SS (type III secretion system) to translocate effectors that subvert different cellular processes to sustain colonization and multiplication. The eukaryotic proteins NHERF2 (Na(+)/H(+) exchanger regulatory factor 2) and AnxA2 (annexin A2), which are involved in regulation of intestinal ion channels, are recruited to the bacterial attachment sites. Using a stable HeLa-NHERF2 cell line, we found partial co-localization of AnxA2 and NHERF2; in EPEC-infected cells, AnxA2 and NHERF2 were extensively recruited to the site of bacterial attachment. We confirmed that NHERF2 dimerizes and found that NHERF2 interacts with AnxA2. Moreover, we found that AnxA2 also binds both the N- and C-terminal domains of the bacterial effector Tir through its C-terminal domain. Immunofluorescence of HeLa cells infected with EPEC showed that AnxA2 is recruited to the site of bacterial attachment in a Tir-dependent manner, but independently of Tir-induced actin polymerization. Our results suggest that AnxA2 and NHERF2 form a scaffold complex that links adjacent Tir molecules at the plasma membrane forming a lattice that could be involved in retention and dissemination of other effectors at the bacterial attachment site.
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Affiliation(s)
- Diana Munera
- Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, U.K
| | - Eric Martinez
- Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, U.K
| | - Svetlana Varyukhina
- CNRS UMR7203, Groupe N. J. Conté, Laboratoire des BioMolécules and Université Pierre et Marie Curie, 75005 Paris, France
| | - Arvind Mahajan
- Cellular Microbiology Group, Division of Infection and Immunity, Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, U.K
| | - Jesus Ayala-Sanmartin
- CNRS UMR7203, Groupe N. J. Conté, Laboratoire des BioMolécules and Université Pierre et Marie Curie, 75005 Paris, France
| | - Gad Frankel
- Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, U.K
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16
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Chuang HC, Ho YH, Lay CJ, Wang LS, Tsai YS, Tsai CC. Different clinical characteristics among Aeromonas hydrophila, Aeromonas veronii biovar sobria and Aeromonas caviae monomicrobial bacteremia. J Korean Med Sci 2011; 26:1415-20. [PMID: 22065896 PMCID: PMC3207043 DOI: 10.3346/jkms.2011.26.11.1415] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Accepted: 09/06/2011] [Indexed: 12/04/2022] Open
Abstract
This study aimed to compare the clinical presentations of Aeromonas hydrophila, A. veronii biovar sobria and A. caviae monomicrobial bacteremia by a retrospective method at three hospitals in Taiwan during an 8-yr period. There were 87 patients with A. hydrophila bacteremia, 45 with A. veronii biovar sobria bacteremia and 22 with A. caviae bacteremia. Compared with A. hydrophila and A. veronii biovar sobria bacteremia, A. caviae bacteremia was more healthcare-associated (45 vs 30 and 16%; P = 0.031). The patients with A. caviae bacteremias were less likely to have liver cirrhosis (27 vs 62 and 64%; P = 0.007) and severe complications such as shock (9 vs 40 and 47%; P = 0.009) and thrombocytopenia (45 vs 67 and 87%; P = 0.002). The APACHE II score was the most important risk factor of Aeromonas bacteremia-associated mortalities. The APACHE II scores of A. caviae bacteremias were lower than A. hydrophila bacteremia and A. veronii biovar sobria bacteremia (7 vs 14 and 16 points; P = 0.002). In conclusion, the clinical presentation of A. caviae bacteremia was much different from A. hydrophila and A. veronii biovar sobria bacteremia. The severity and mortality of A. caviae bacteremia were lower than A. hydrophila or A. veronii biovar sobria bacteremia.
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Affiliation(s)
- Han-Chuan Chuang
- Division of Infectious Disease, Department of Medicine, Buddhist Taipei Tzu Chi General Hospital, Taipei, Taiwan
| | - Yu-Huai Ho
- Division of Infectious Disease, Department of Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Chorng-Jang Lay
- Division of Infectious Disease, Department of Medicine, Buddhist Dalin Tzu Chi General Hospital, Hualien, Taiwan
- School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Lih-Shinn Wang
- Division of Infectious Disease, Department of Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
- School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Yeong-Shu Tsai
- Division of Infectious Disease, Department of Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Chen-Chi Tsai
- Division of Infectious Disease, Department of Medicine, Buddhist Dalin Tzu Chi General Hospital, Hualien, Taiwan
- School of Medicine, Tzu Chi University, Hualien, Taiwan
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17
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Debellis L, Diana A, Arcidiacono D, Fiorotto R, Portincasa P, Altomare DF, Spirlì C, de Bernard M. The Vibrio cholerae cytolysin promotes chloride secretion from intact human intestinal mucosa. PLoS One 2009; 4:e5074. [PMID: 19333391 PMCID: PMC2659442 DOI: 10.1371/journal.pone.0005074] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 03/05/2009] [Indexed: 12/02/2022] Open
Abstract
Background The pathogenicity of the Vibrio cholerae strains belonging to serogroup O1 and O139 is due to the production of virulence factors such as cholera toxin (CT) and the toxin-coregulated pilus (TCP). The remaining serogroups, which mostly lack CT and TCP, are more frequently isolated from aquatic environmental sources than from clinical samples; nevertheless, these strains have been reported to cause human disease, such as sporadic outbreaks of watery diarrhoea and inflammatory enterocolitis. This evidence suggested the possibility that other virulence factor(s) than cholera toxin might be crucial in the pathogenesis of Vibrio cholerae-induced diarrhoea, but their nature remains unknown. VCC, the hemolysin produced by virtually all Vibrio cholerae strains, has been proposed as a possible candidate, though a clear-cut demonstration attesting VCC as crucial in the pathogenesis of Vibrio cholerae-induced diarrhoea is still lacking. Methodology/Principal Findings Electrophysiological parameters and paracellular permeability of stripped human healthy colon tissues, obtained at subtotal colectomy, mounted in Ussing chamber were studied in the presence or absence of VCC purified from culture supernatants of V. cholerae O1 El Tor strain. Short circuit current (ISC) and transepithelial resistance (RT) were measured by a computerized voltage clamp system. The exposure of sigmoid colon specimens to 1 nM VCC resulted in an increase of ISC by 20.7%, with respect to the basal values, while RT was reduced by 12.3%. Moreover, increase in ISC was abolished by bilateral Cl− reduction. Conclusion/Significance Our results demonstrate that VCC, by forming anion channels on the apical membrane of enterocytes, triggers an outward transcellular flux of chloride. Such an ion movement, associated with the outward movement of Na+ and water, might be responsible for the diarrhoea caused by the non-toxigenic strains of Vibrio cholerae.
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Affiliation(s)
- Lucantonio Debellis
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | - Anna Diana
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | | | - Romina Fiorotto
- Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut, United States of America
| | - Piero Portincasa
- Clinica Medica “A. Murri”, Department of Internal and Public Medicine, University Medical School, Bari, Italy
| | - Donato Francesco Altomare
- Department of Emergency and Organ Transplantation, General Surgery and Liver Transplantation Units, University of Bari, Policlinico, Bari, Italy
| | - Carlo Spirlì
- Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut, United States of America
| | - Marina de Bernard
- Venetian Institute of Molecular Medicine, Padua, Italy
- Department of Biology, University of Padua, Padua, Italy
- * E-mail:
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18
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van der Voort M, Abee T. Transcriptional regulation of metabolic pathways, alternative respiration and enterotoxin genes in anaerobic growth of Bacillus cereus ATCC 14579. J Appl Microbiol 2009; 107:795-804. [PMID: 19302486 DOI: 10.1111/j.1365-2672.2009.04252.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
AIMS To assess genes specifically activated during anaerobic growth that are involved in metabolism and pathogenesis of the foodborne pathogen Bacillus cereus. METHODS AND RESULTS Growth under anaerobic conditions in Brain Heart Infusion (BHI) broth revealed a reduced growth rate and lower yield as compared to growth under aerobic conditions. Subsequently, comparative transcriptome analysis showed specific genes induced under anaerobic conditions. These included novel genes identified for anaerobic growth of B. cereus, encoding metabolic pathways, such as the arginine deiminase pathway (ArcABDC), formate dehydrogenase (FdhF) and pyruvate formate lyase (Pfl), and alternative respiratory proteins, such as arsenate reductases. Notably, haemolytic enzyme encoding genes were induced during anaerobic growth, and enterotoxin genes were induced in high cell density transition and stationary phases of aerobic cultures. CONCLUSIONS These data point to induction of stress adaptation and pathogenicity factors and rearrangements of expression of metabolic pathways in response to oxygen limitations in B. cereus. SIGNIFICANCE AND IMPACT OF THE STUDY The reported changes in gene expression show that the foodborne pathogen B. cereus can adjust to anaerobic conditions, such as encountered in the human GI-tract.
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Affiliation(s)
- M van der Voort
- TI Food and Nutrition, Wageningen, The Netherlands and Laboratory of Food Microbiology, Wageningen University, Wageningen, the Netherlands
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19
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Aeromonas Spp. Human Isolates Induce Apoptosis of Murine Macrophages. Curr Microbiol 2008; 58:252-7. [DOI: 10.1007/s00284-008-9316-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 09/30/2008] [Accepted: 10/13/2008] [Indexed: 02/05/2023]
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20
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Molecular pathogenesis of Shigella spp.: controlling host cell signaling, invasion, and death by type III secretion. Clin Microbiol Rev 2008; 21:134-56. [PMID: 18202440 DOI: 10.1128/cmr.00032-07] [Citation(s) in RCA: 398] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Shigella spp. are gram-negative pathogenic bacteria that evolved from harmless enterobacterial relatives and may cause devastating diarrhea upon ingestion. Research performed over the last 25 years revealed that a type III secretion system (T3SS) encoded on a large plasmid is a key virulence factor of Shigella flexneri. The T3SS determines the interactions of S. flexneri with intestinal cells by consecutively translocating two sets of effector proteins into the target cells. Thus, S. flexneri controls invasion into EC, intra- and intercellular spread, macrophage cell death, as well as host inflammatory responses. Some of the translocated effector proteins show novel biochemical activities by which they intercept host cell signal transduction pathways. An understanding of the molecular mechanisms underlying Shigella pathogenesis will foster the development of a safe and efficient vaccine, which, in parallel with improved hygiene, should curb infections by this widespread pathogen.
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21
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Nagy JO, Zhang Y, Yi W, Liu X, Motari E, Song JC, Lejeune JT, Wang PG. Glycopolydiacetylene nanoparticles as a chromatic biosensor to detect Shiga-like toxin producing Escherichia coli O157:H7. Bioorg Med Chem Lett 2007; 18:700-3. [PMID: 18086524 DOI: 10.1016/j.bmcl.2007.11.055] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/14/2007] [Accepted: 11/15/2007] [Indexed: 11/17/2022]
Abstract
Shiga toxin-producing Escherichia coli organisms (STEC) were detected by Gal-alpha1,4-Gal glycopolydiacetylene (GPDA) nanoparticles through the selective binding between Shiga toxin and GPDA nanoparticles. The binding produced a colorimetric change in the absorption wavelength of the GPDA nanoparticles. This method provides a highly selective, rapid, sensitive, and quantitative approach for the detection of STEC.
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Affiliation(s)
- Jon O Nagy
- ATERIS Technologies, Bozeman, MT 59718, USA.
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22
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Kwiatkowska K, Hordejuk R, Szymczyk P, Kulma M, Abdel-Shakor AB, Płucienniczak A, Dołowy K, Szewczyk A, Sobota A. Lysenin-His, a sphingomyelin-recognizing toxin, requires tryptophan 20 for cation-selective channel assembly but not for membrane binding. Mol Membr Biol 2007; 24:121-34. [PMID: 17453419 DOI: 10.1080/09687860600995540] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Lysenin is 297 amino acid long toxin derived from the earthworm Eisenia foetida which specifically recognizes sphingomyelin and induces cell lysis. We synthesized lysenin gene supplemented with a polyhistidine tag, subcloned it into the pT7RS plasmid and the recombinant protein was produced in Escherichia coli. In order to obtain lysenin devoid of its lytic activity, the protein was mutated by substitution of tryptophan 20 by alanine. The recombinant mutant lysenin-His did not evoke cell lysis, although it retained the ability to specifically interact with sphingomyelin, as demonstrated by immunofluorescence microscopy and by dot blot lipid overlay and liposome binding assays. We found that the lytic activity of wild-type lysenin-His was correlated with the protein oligomerization during interaction with sphingomyelin-containing membranes and the amount of oligomers was increased with an elevation of sphingomyelin/lysenin ratio. Blue native gel electrophoresis indicated that trimers can be functional units of the protein, however, lysenin hexamers and nanomers were stabilized by chemical cross-linking of the protein and by sodium dodecyl sulfate. When incorporated into planar lipid bilayers, wild type lysenin-His formed cation-selective channels in a sphingomyelin-dependent manner. We characterized the channel activity by establishing its various open/closed states. In contrast, the mutant lysenin-His did not form channels and its correct oligomerization was strongly impaired. Based on these results we suggest that lysenin oligomerizes upon interaction with sphingomyelin in the plasma membrane, forming cation-selective channels. Their activity disturbs the ion balance of the cell, leading eventually to cell lysis.
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23
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Ulett GC, Adderson EE. Regulation of Apoptosis by Gram-Positive Bacteria: Mechanistic Diversity and Consequences for Immunity. ACTA ACUST UNITED AC 2006; 2:119-141. [PMID: 19081777 DOI: 10.2174/157339506776843033] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Apoptosis, or programmed cell death (PCD), is an important physiological mechanism, through which the human immune system regulates homeostasis and responds to diverse forms of cellular damage. PCD may also be involved in immune counteraction to microbial infection. Over the past decade, the amount of research on bacteria-induced PCD has grown tremendously, and the implications of this mechanism on immunity are being elucidated. Some pathogenic bacteria actively trigger the suicide response in critical lineages of leukocytes that orchestrate both the innate and adaptive immune responses; other bacteria proactively prevent PCD to benefit their own survival and persistence. Currently, the microbial virulence factors, which represent the keys to unlocking the suicide response in host cells, are a primary focus of this field. In this review, we discuss these bacterial "apoptosis regulatory molecules" and the apoptotic events they either trigger or prevent, the host target cells of this regulatory activity, and the possible ramifications for immunity to infection. Gram-positive pathogens including Staphylococcus, Streptococcus, Bacillus, Listeria, and Clostridia species are discussed as important agents of human infection that modulate PCD pathways in eukaryotic cells.
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Affiliation(s)
- Glen C Ulett
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105-2794, USA
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24
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Pantano S, Montecucco C. A molecular model of the Vibrio cholerae cytolysin transmembrane pore. Toxicon 2005; 47:35-40. [PMID: 16330061 DOI: 10.1016/j.toxicon.2005.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 08/31/2005] [Accepted: 09/22/2005] [Indexed: 01/05/2023]
Abstract
The cytotoxic activity of some of the most pathogenic strains of Vibrio cholerae is associated with a cytolysin protein (VCC), which forms oligomeric transmembrane pores and changes the permeability of intestinal cells. We present here a model structure of the transmembrane pore of VCC based on sequence comparison with other pore-forming toxins. VCC is suggested to form a transmembrane beta-barrel pore with a relatively large trans vestibule region. Calculations of the electrostatic profile within the pore lumen provide a rationale for the low conductance and selectivity of the VCC ion channel.
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Affiliation(s)
- Sergio Pantano
- Venetian Institute of Molecular Medicine (VIMM),Via Orus 2, 35129, Padova, Italy.
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25
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Abstract
Astroviruses are one of the leading causes of diarrhea worldwide. In spite of its impact on human health, little is known about astrovirus pathogenesis. One reason for this may be the lack of a suitable small animal model for infection. In recent years, there has been increasing information on the mechanism of astrovirus-induced disease in mammals (including humans) and birds. This review summarizes our current state of knowledge on astrovirus pathogenesis.
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Affiliation(s)
- Lindsey A Moser
- Department of Medical Microbiology and Immunology, University of Wisconsin, 1300 University Ave, Madison, WI 53575, USA
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