scholarly journals Ammonia generation by tryptophan synthase drives a key genetic difference between genital and ocular Chlamydia trachomatis isolates

2019 ◽  
Vol 116 (25) ◽  
pp. 12468-12477 ◽  
Author(s):  
Shardulendra P. Sherchand ◽  
Ashok Aiyar

A striking difference between genital and ocular clinical isolates of Chlamydia trachomatis is that only the former express a functional tryptophan synthase and therefore can synthesize tryptophan by indole salvage. Ocular isolates uniformly cannot use indole due to inactivating mutations within tryptophan synthase, indicating a selection against maintaining this enzyme in the ocular environment. Here, we demonstrate that this selection occurs in two steps. First, specific indole derivatives, produced by the human gut microbiome and present in serum, rapidly induce expression of C. trachomatis tryptophan synthase, even under conditions of tryptophan sufficiency. We demonstrate that these indole derivatives function by acting as de-repressors of C. trachomatis TrpR. Second, trp operon de-repression is profoundly deleterious when infected cells are in an indole-deficient environment, because in the absence of indole, tryptophan synthase deaminates serine to pyruvate and ammonia. We have used biochemical and genetic approaches to demonstrate that expression of wild-type tryptophan synthase is required for the bactericidal production of ammonia. Pertinently, although these indole derivatives de-repress the trpRBA operon of C. trachomatis strains with trpA or trpB mutations, no ammonia is produced, and no deleterious effects are observed. Our studies demonstrate that tryptophan synthase can catalyze the ammonia-generating β-elimination reaction within any live bacterium. Our results also likely explain previous observations demonstrating that the same indole derivatives inhibit the growth of other pathogenic bacterial species, and why high serum levels of these indole derivatives are favorable for the prognosis of diseased conditions associated with bacterial dysbiosis.

2007 ◽  
Vol 67 (05) ◽  
Author(s):  
N Shabani ◽  
T Puchner ◽  
H Schütze ◽  
U Jeschke ◽  
I Mylonas ◽  
...  

2020 ◽  
Vol 9 (2) ◽  
pp. 78-88
Author(s):  
Mulugeta Mulat ◽  
Raksha Anand ◽  
Fazlurrahman Khan

The diversity of indole concerning its production and functional role has increased in both prokaryotic and eukaryotic systems. The bacterial species produce indole and use it as a signaling molecule at interspecies, intraspecies, and even at an interkingdom level for controlling the capability of drug resistance, level of virulence, and biofilm formation. Numerous indole derivatives have been found to play an important role in the different systems and are reported to occur in various bacteria, plants, human, and plant pathogens. Indole and its derivatives have been recognized for a defensive role against pests and insects in the plant kingdom. These indole derivatives are produced as a result of the breakdown of glucosinolate products at the time of insect attack or physical damages. Apart from the defensive role of these products, in plants, they also exhibit several other secondary responses that may contribute directly or indirectly to the growth and development. The present review summarized recent signs of progress on the functional properties of indole and its derivatives in different plant systems. The molecular mechanism involved in the defensive role played by indole as well as its’ derivative in the plants has also been explained. Furthermore, the perspectives of indole and its derivatives (natural or synthetic) in understanding the involvement of these compounds in diverse plants have also been discussed.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 392.1-392
Author(s):  
E. Pigatto ◽  
M. Schiesaro ◽  
M. Caputo ◽  
M. Beggio ◽  
P. Galozzi ◽  
...  

Background:Gastrointestinal (GI) involvement is very common in patients with Systemic Sclerosis (SSc). The pathophysiology of GI manifestations has not yet been defined. Cell-mediated immunological reactions appear to lead to endothelial damage resulting in fibrosis. The risk of developing malnutrition reinforces the need to better understand GI pathophysiology in these patients.Objectives:The study aimed to evaluate GI symptoms (GIT 2.0) and malnutrition status (MUST) and to determine specific bacterial changes in gut microbiome by investigating the possible presence of positive hot spots in bacterial species in SSc patients and their potential role in the disease progression. We also evaluated serum levels of adipokines and cytokines involved in the pathogenesis of SSc and their role, in addition to gut microbiome, in predicting the onset of GI involvement and malnutrition in SSc patients.Methods:We enrolled 25 scleroderma patients (EULAR/ACR 2013 criteria). UCLA-SCTC GIT 2.0 questionnaire to evaluate GI symptoms and MUST to investigate the risk of malnutrition were used. Gut microbiome was analyzed and the samples were subjected to extraction for the 16S rRNA gene (Earth Microbiome Project and the NIH-Human Microbiome Project). The microbiome was investigated at phenotypic and genotypic level. Serum levels of cytokines and adipokines (adiponectin and leptin) were evaluated by ELISA.Results:79.9% of patients had GERD and 63.5% abdominal distension at GIT 2.0 questionnaires. 48% of patients had moderate risk of malnutrition (MUST=2) and 12% had high risk (MUST=3). Gut microbioma: 19 patients (76%) had low similarity and 11 (44%) low diversity compared to the healthy population. The prevailing enterotypes of gut microbiome was Bacteroides (80%) and Prevotella (20%). The genotypic evaluation showed a reduced concentration of: gluten-digesting (Lactobacillus); lactose-digesting (Faecalibacterium); vitamin K-producing (Enterococcus, Desulfovibrio and Veillonella); acetaldehyde-degrading bacteria. 24 patients (96%) showed a reduction in bacteria devoted to maintaining weight control (Bifidobacterium and Ruminococcus). The patients had an altered intestinal permeability with less mucolytic bacteria (Bacteroides) and reduced production of LPS (Enterobacter and Escherichia). Low levels of butyrate (Eubacterium and Clostridium), acetate and propionate were found for SCFA-producing bacteria. Potentially pathogenic bacteria were also investigated: Salmonella was found in 14 (56%), Klebsiella in 9 (36%) and Enterococcus Faecalis in 3 (12%) patients. 11 (44%) patients had elevated serum levels of IL10 and IL12; 4 (16%) had high value of leptin. Correlation was found in patients who had a reduced concentration of gluten-digesting bacteria and MUST. Elevated MUST was correlated with serological increase in IL17A and IFN-α. Serum levels of IL12 and IL10 were found to correlate with specific bacteria alterations: high concentration of acetaldehyde-producing bacteria and low levels of acetaldehyde-degrade bacteria (also correlated with high serum levels of IL6), mucolytic bacteria and producers of hydrogen sulphide, acetate and propionate. Finally, reduced levels of mucolytic bacteria and acetate producing bacteria correlated with high serum leptin levels.Conclusion:The relationship between the gut microbiome and SSc seems to be multifactorial. In our study genotypic changes of gut microbioma might play a role in damaging the permeability of the mucosa and increasing risk of malnutrition. The evaluation of gut microbiome and cytokine profile is probably going to be of value in the follow-up of SSc. However, further studies are needed to clarify the impact of GI dysbiosis on the immune system in SSc.References:[1]Patrone V. et al. Gut microbiota profile in systemic sclerosis patients with and without clinical evidence of gastrointestinal involvement, Sci Rep. 2017; 7: 14874Disclosure of Interests:None declared


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1093.1-1093
Author(s):  
G. Pellegrino ◽  
K. Stefanantoni ◽  
F. Facioni ◽  
C. Angelelli ◽  
A. Gigante ◽  
...  

Background:Electrocardiographic (ECG) abnormalities are described in 25-75% Systemic Sclerosis (SSc) cases and they are associated with other systemic manifestations as well as with a worse prognosis. There is an increasing need for clinical and laboratory biomarkers to ameliorate the diagnostic and therapeutic approaches to patients with ECG abnormalities, due to their actual low sensitivity and specificity. Adipokines are circulating proteins that appear dysregulated in SSc and leptin in particular is synthesized in response to inflammatory conditions and seems to play a proinflammatory and pro-fibrotic action in SSc. Interesting, many studies in the last years have underlined its role in the cardiac remodeling mechanisms and in the development of cardiac fibrosis in other chronic diseases.Objectives:Aim of our study is to evaluate the role of leptin in the development of cardiac rhythm disorders (CRD) during SSc. Furthermore, by the analysis of the clinical and demographical parameters of our SSc patients, we tried to define other possible features associated with increased serum leptin concentration.Methods:We included eighty-five SSc patients, fulfilling the 2013 ACR/EULAR classification criteria, attending the Regional Rare Disease Center of Policlinico Umberto I of Rome. Fifty presented significant CRD at non-invasive diagnostic techniques (12 Lead ECG, 24-hour Holter ECG). Demographic, clinical, conventional cardiovascular risk factors were examined; instrumental and laboratory assessments were obtained, together with ECG recordings. Thirty-five SSc patients without pathologic finding at ECG traces, matched for demographic and clinical features, were recruited as the control group. In all cases, after obtaining written informed consent, blood samples were taken to measure serum levels of leptin using an ELISA assay (Life Technologies-Italia).Results:The fifty SSc patients with CRD (mean age 51±15 years; F:M 41:9) had pulmonary fibrosis (PF) in 32 cases (64%) and a BMI >25Kg/m2in 22 (44%) while in the control group of thirty-five SSc patients (mean age 49±16 years; F:M 33:2) PF was found in 15 (43%) and a BMI >25Kg/m2in 9 (35%); We detected significantly higher median values of serum leptin in SSc patients with CRD compared to the control group (12027 pg/ml IQR 12314 versus 6392 pg/ml IQR 7103;p 0,0009). Additionally, SSc patients with a BMI> 25 kg/m2(31 cases) as well as those with PF (47 cases) showed a significantly higher median serum leptin levels compared to those with BMI <25 kg/m2(13161 pg/ml IQR 13610 versus 8187 pg/ml IQR 8255;p 0,0008) and those without PF (11740 pg/ml IQR 11940 versus 7616 pg/ml IQR 7855;p 0,0079).Conclusion:To our knowledge this is the first report on high serum levels of leptin in SSc patients with CRD that also confirms its increase in those cases with a BMI >25 kg/m2and with PF, according to scientific literature data. The role of leptin in the pathogenesis of SSc remains unclear although it is already known its involvement in the development of cardiac fibrosis during other chronic diseases. On the basis of these results we speculate on leptin involvement in the pathogenesis of CRD during SSc, although further studies are needed with larger cohort of patients.References:[1]Vacca A et al. Rheumatology, 2014[2]Tyndall AJ et al. Ann Rheum Dis, 2010[3]Muresan L et al. Iran J Pub Health, 2017[4]Sanna T et al. Indian Pacing Electrophysiol J, 2009[5]Riccieri V et al. Clin Exp Rheumatol, 2011[6]Żółkiewicz J et al. Arch Dermatol Res, 2019[7]Huby AC et al. Circulation, 2015[8]Shulze PC et al. Clin Chim Acta, 2005[9]Van de Hoogen F et al. Arthritis Rheum, 2013[10]Gui X et al. Biochem Biophys Res Commun, 2018Disclosure of Interests:Greta Pellegrino: None declared, Katia Stefanantoni Consultant of: ItalfarmacoBoehringer Ingelheim, Fausta Facioni: None declared, Carlotta Angelelli: None declared, Antonietta Gigante: None declared, Roberto Badagliacca: None declared, Carmine Dario Vizza: None declared, Sergio Morelli: None declared, Edoardo Rosato: None declared, Valeria Riccieri: None declared


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Selina Traxler ◽  
Gina Barkowsky ◽  
Radost Saß ◽  
Ann-Christin Klemenz ◽  
Nadja Patenge ◽  
...  

AbstractInfluenza A is a serious pathogen itself, but often leads to dangerous co-infections in combination with bacterial species such as Streptococcus pyogenes. In comparison to classical biochemical methods, analysis of volatile organic compounds (VOCs) in headspace above cultures can enable destruction free monitoring of metabolic processes in vitro. Thus, volatile biomarkers emitted from biological cell cultures and pathogens could serve for monitoring of infection processes in vitro. In this study we analysed VOCs from headspace above (co)-infected human cells by using a customized sampling system. For investigating the influenza A mono-infection and the viral-bacterial co-infection in vitro, we analysed VOCs from Detroit cells inoculated with influenza A virus and S. pyogenes by means of needle-trap micro-extraction (NTME) and gas chromatography mass spectrometry (GC-MS). Besides the determination of microbiological data such as cell count, cytokines, virus load and bacterial load, emissions from cell medium, uninfected cells and bacteria mono-infected cells were analysed. Significant differences in emitted VOC concentrations were identified between non-infected and infected cells. After inoculation with S. pyogenes, bacterial infection was mirrored by increased emissions of acetaldehyde and propanal. N-propyl acetate was linked to viral infection. Non-destructive monitoring of infections by means of VOC analysis may open a new window for infection research and clinical applications. VOC analysis could enable early recognition of pathogen presence and in-depth understanding of their etiopathology.


2008 ◽  
Vol 295 (2) ◽  
pp. E254-E261 ◽  
Author(s):  
Shiguang Liu ◽  
Jianping Zhou ◽  
Wen Tang ◽  
Rochelle Menard ◽  
Jian Q. Feng ◽  
...  

Autosomal recessive hypophosphatemic rickets (ARHR), which is characterized by renal phosphate wasting, aberrant regulation of 1α-hydroxylase activity, and rickets/osteomalacia, is caused by inactivating mutations of dentin matrix protein 1 ( DMP1). ARHR resembles autosomal dominant hypophosphatemic rickets (ADHR) and X-linked hypophosphatemia (XLH), hereditary disorders respectively caused by cleavage-resistant mutations of the phosphaturic factor FGF23 and inactivating mutations of PHEX that lead to increased production of FGF23 by osteocytes in bone. Circulating levels of FGF23 are increased in ARHR and its Dmp1-null mouse homologue. To determine the causal role of FGF23 in ARHR, we transferred Fgf23 deficient/enhanced green fluorescent protein (eGFP) reporter mice onto Dmp1-null mice to create mice lacking both Fgf23 and Dmp1. Dmp1−/− mice displayed decreased serum phosphate concentrations, inappropriately normal 1,25(OH)2D levels, severe rickets, and a diffuse form of osteomalacia in association with elevated Fgf23 serum levels and expression in osteocytes. In contrast, Fgf23−/− mice had undetectable serum Fgf23 and elevated serum phosphate and 1,25(OH)2D levels along with severe growth retardation and focal form of osteomalacia. In combined Dmp1−/−/Fgf23−/−, circulating Fgf23 levels were also undetectable, and the serum levels of phosphate and 1,25(OH)2D levels were identical to Fgf23−/− mice. Rickets and diffuse osteomalacia in Dmp1-null mice were transformed to severe growth retardation and focal osteomalacia characteristic of Fgf23-null mice. These data suggest that the regulation of extracellular matrix mineralization by DMP1 is coupled to renal phosphate handling and vitamin D metabolism through a DMP1-dependent regulation of FGF23 production by osteocytes.


2008 ◽  
Vol 95 (2) ◽  
pp. 283-286 ◽  
Author(s):  
E. CESARE ◽  
M. PREVITI ◽  
M. C. INGEMI ◽  
G. F. BAGNATO ◽  
D. CUCINOTTA

1980 ◽  
Vol 94 (3) ◽  
pp. 341-345 ◽  
Author(s):  
Jens Faber ◽  
Carsten Kirkegaard ◽  
Ib Bo Lumholtz ◽  
Kaj Siersbæk-Nielsen ◽  
Thorkild Friis

Abstract. Serum levels of thyroxine, 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3), 3,3'-diiodothyronine (3,3'-T2), 3',5'-diiodothyronine (3',5'-T2) and TSH were measured in two clinical situations which are both known to induce a low serum T3 high serum rT3 syndrome: 1) during the early course of acute myocardial infarction (AMI) and after recovery, and 2) before and during one week's propranolol medication (20 mg 4 times a day). In 10 patients with AMI serum levels of the iodothyronines were unchanged on admission to hospital (in average 6.6 h after onset of symptoms). However, already 24 h after onset of symptoms serum T3 and 3,3'T2 were reduced whereas serum rT3 and 3',5'-T2 were increased. Serum T3 and 3,3'-T2 reached a nadir on day 4 and 3, respectively, whereas serum rT3 and 3',5'-T2 reached peak values 24 h after onset of symptoms. In eight healthy, euthyroid volunteers propranolol medication induced similar changes in iodothyronine concentration as AMI did. However, the alterations were more delayed. Serum T3 decreased slowly reaching statistically significantly reduced values on day 7. Serum rT3 and 3',5'-T2 were significantly enhanced from day 3 and 4, respectively. A close parallelism in alterations of serum T3 and 3,3'-T2 levels was observed. Our data suggest that T3 in the two situations studied is a major precursor for 3,3'-T2 probably as a consequence of reduced 5'-deiodinase activity. It seems possible that the mechanisms affecting the metabolism of the iodothyronines in AMI and during propranolol medication involved the same enzyme system. However, the late appearance of the alterations in serum iodothyronines levels during propranolol medication might indicate different modes of action.


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