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Cladia aggregate (SW) Nyl is a lichenized fungi in the family Cladoniaceae producing characteristic secondary metabolites of interest. There are only limited chemical studies relating to the genus Cladia. A chemical study of the lichen C. aggregata was conducted and their chemical constituents were elucidated by ultra-performance liquid chromatography-electrospray ionization/triple-quadrupole tandem-mass spectrometry analysis. It is the first time report of structure analysis of its metabolite by liquid chromatography-mass spectrometry/mass spectrometry. The molecular masses for 20 compounds were detected from different fractions. Seven compounds were elucidated with mass spectrometry/mass spectrometry fragmentation pattern analysis. Barbatic acid (12) was identified as the major compound being common to all fractions. The identified compounds belong to depsides (2, 11, 12 and 20), dibenzofurans (13, 18) and sugar derivatives (1) which are usually distributed in lichens.
Subject(s)
Ascomycota , Lichens , Tandem Mass Spectrometry , Tandem Mass Spectrometry/methods , Spectrometry, Mass, Electrospray Ionization/methods , Chromatography, High Pressure Liquid/methods , Chromatography, Liquid , Organic Chemicals , Depsides , SugarsABSTRACT
Oxystelma esculentum has been used as a folk medicine to treat jaundice, throat infections, and skin problems. In the current study, the bone fracture-healing properties of a flavonoid-enriched fraction (Oxy50-60F) of O. esculentum were investigated in Swiss mice using a drill-hole injury model. Oxy50-60F (1 mg/kg/day, 5 mg/kg/day, and 10 mg/kg/day) was administered orally (from the next day) after a 0.6 mm drill-hole injury in mice femur mid-diaphysis for 7 days and 14 days. Parathyroid hormone (40 µg/kg; 5 times/week) was given subcutaneously as the positive control. Confocal imaging for bone regeneration, micro-architecture of femur bones, ex vivo mineralization, hematoxyline and eosin staining, measurement of reactive oxygen species, and gene expression of osteogenic and anti-inflammatory genes were studied. Quercetin, kaempferol, and isorhamnetin glycosides were identified in the active fraction using mass spectrometry techniques. Our results confirm that Oxy50-60F treatment promotes fracture healing and callus formation at drill-hole sites and stimulates osteogenic and anti-inflammatory genes. Oxy50-60F administration to fractured mice exhibited significantly better micro-CT parameters in a dose-dependent manner and promoted nodule mineralization at days 7 and 14 post-injury. Oxy50-60F also prevents ROS generation by increasing expression of the SOD2 enzyme. Overall, this study reveals that Oxy50-60F has bone regeneration potential in a cortical bone defect model, which supports its use in delayed-union and non-union fracture cases.
Subject(s)
Fracture Healing , Fractures, Bone , Mice , Animals , Flavonoids/pharmacology , Liquid Chromatography-Mass Spectrometry , Chromatography, Liquid , Tandem Mass Spectrometry , Fractures, Bone/drug therapy , Anti-Inflammatory AgentsABSTRACT
Orofacial injuries constitute the medico-legal cases reported, especially, in cases associated with road traffic accidents, assaults, and violence making it an emerging healthcare problem. Therefore, it is of interest to document data on the maxillofacial trauma and fractures among Indians. 150 subjects within the age of 15 to 60 years with maxillofacial fractures, detailed medical history including demographics, radiographs, medical history, associated injuries, and etiology of fractures were used for this study. Sites for both maxillary and mandibular fractures were noted. The type of intubation (medical insertion procedure) used and post-operative complications were also recorded. Lefort I, II, and III fractures were seen in 4%, 12%, 6% subjects respectively, whereas, ZMC fracture was seen in 66% study subjects. Mandibular fractures were most commonly seen in the para-symphysis region with 30% subjects followed by condylar region with 28.66% subjects. Data shows that maxillofacial trauma has a high incidence in India with RTA (road traffic accidents being the most common reason for the trauma seen in young males with significant concomitant injuries. Most common fracture is seen in mandible region. However, they can be managed well with very few postoperative complications.
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BACKGROUND: Oral cancer is a rapidly growing disease among Indian subjects mainly in the low socioeconomic group. Socially and economically marginalized subjects are at high risk for oral cancer because of smoke and smokeless tobacco consumption. AIM: To evaluate the prevalence of precancerous lesions and oral cancer and evaluate tobacco as a causative factor in Indian subjects visiting the outpatient department of the institute. METHODS: Around 658 subjects were analyzed for frequency of premalignant lesions and oral malignancy in Indian subjects from the low socioeconomic group. Patients visited for pain, burning, or ulceration in the oral cavity were clinically assessed for any tissue growths, leathery alterations, ulcerative changes, and white or red lesions in the oral cavity. Results: The overall prevalence of smokeless and smoking tobacco was 78.8% (n=518) and 65.2% (n=429) respectively in the present study. Around 39.8% (n=262) of samples were stained positive for precancerous and cancerous lesions of the oral cavity. The highest number of positive samples were from buccal mucosa with 36.2% (n=238) subjects and 6.1% (n=40) for labial mucosa. CONCLUSIONS: Oral cancer is highly prevalent in Indian subjects owing to high tobacco consumption rates and habits warranting the cessation center a priority. Also, early detection and screening are vital to attaining better outcomes. More tobacco cessation centers are needed to stop the habit and early diagnosis will prevent dysplastic changes.
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RATIONALE: Cajanus scarabaeoides, belonging to the Fabaceae family, is an underutilized herb and traditionally used to treat several ailments. However, it is not well explored phytochemically. Therefore, mass spectrometry (MS)-based phytochemical analysis was carried out to investigate the bioactive ingredients of the herb. METHODS: A ultra-performance liquid chromatography (UPLC) coupled to photodiode array detection (PDA) and electrospray ionization (ESI) tandem mass spectrometry (UPLC-PDA-ESI-MS/MS) system was used for the qualitative and quantitative analysis of phytochemicals. The chromatographic separation was achieved on the Acquity BEH C18 column (150 × 2.1 mm, 1.7 µm) using a gradient system consisting of three solvents, acetonitrile, methanol, and 0.1% formic acid, used at a flow rate of 0.300 ml/min. RESULTS: Sixteen bioactive ingredients (gallic acid, gallocatechin, epigallocatechin, catechin, procyanidin dimer, epicatechin, procyanidin trimer, isoorientin, orientin, vitexin, isovitexin, quercetin-mono-O-glycoside, isoquercitrin, luteolin-7-O-glucoside, quercetin, and luteolin) were identified and structurally characterized. Consequently, 12 compounds were reported for the first time from C. scarabaeoides, and 13 were quantitatively determined in different seasons. Isoorientin (10.2-7.1% w/w) and orientin (5.78-5.17% w/w) were the most abundant constituents in the dry weight of plant material, followed by vitexin and isovitexin in the rainy season. CONCLUSIONS: The phytochemical investigation has revealed that C. scarabaeoides could be a potential alternate source of bioactive ingredients, namely, isoorientin, orientin, vitexin, and isovitexin, contributing to further exploration of its biological activity. In addition, analytical methods can be used for the rapid identification and quantification of bioactive ingredients in C. scarabaeoides.
Subject(s)
Cajanus , Proanthocyanidins , Tandem Mass Spectrometry/methods , Seasons , Chromatography, High Pressure Liquid/methods , Quercetin , Chromatography, LiquidABSTRACT
Cigarette smoke (CS) induced emphysema and chronic pulmonary inflammation are major comorbidities of chronic obstructive pulmonary disease (COPD), a major cause of morbidity and mortality worldwide. CS exposure exacerbates pulmonary inflammation and compromises immunity to various infections. Aurintricarboxylic acid (ATA) is a polyanionic aromatic compound especially recognized for its anti-inflammatory, nucleic acid, and protein interaction inhibition properties. The study was designed to investigate the anti-inflammatory role of ATA against cigarette smoke extract (CSE) induced pulmonary inflammation. Nicotine concentration was quantified in CSE by UPLC/MS technique. In vitro, fluorescence microscopy, and flow cytometry was performed in CSE stimulated alveolar epithelial cells to determine the effect of ATA on oxidative stress-mediated cellular apoptosis. In vivo, pulmonary inflammation was induced in male Wistar rats via a modified non-invasive intratracheal instillation of cigarette smoke extract (100 µl/animal) twice a week for 8 weeks and post-treated with ATA (10 mg/kg) intraperitoneally for 15 days. Lung homogenates were assessed for MDA and GSH. Lung tissues were subjected to western blotting and histopathological analysis. As result, ATA reduced CSE-induced chromatin condensation, fragmentation, cellular apoptosis in alveolar epithelial cells, and apoptotic biomarkers expression including BAX and Caspase-3 in the lungs. ATA reduced inflammation by normalizing redox balance reflected by MDA/GSH levels. ATA obviated airspace enlargement, fiber deposition, and immune cell infiltration. Reduced inflammation was accompanied by inhibition of inflammatory biomarkers TNF-α, TNFR1, TWEAK, and NF-Ò¡B/p65 activation and nuclear translocation. ATA efficaciously diminished the oxidative stress and pulmonary inflammation associated with lung pathogenesis through TNF-α/TNFR1/NF-Ò¡B/p65 signaling pathway. HIGHLIGHTSATA treatment attenuates CSE-stimulated chromatin condensation, fragmentation, and cellular apoptosis in alveolar epithelial cells.ATA treatment inhibits CSE stimulated activation and nuclear translocation of NF-Ò¡B/p65.ATA treatment diminishes CSE-induced oxidant injury, apoptosis, and emphysema-like phenotypic changes in the lungs.ATA inhibits lung inflammation via suppression of the NF-Ò¡B/p65 signaling pathway.
Subject(s)
Cigarette Smoking , Emphysema , Pneumonia , Pulmonary Emphysema , Male , Rats , Animals , Receptors, Tumor Necrosis Factor, Type I/toxicity , Receptors, Tumor Necrosis Factor, Type I/metabolism , Aurintricarboxylic Acid/toxicity , Aurintricarboxylic Acid/metabolism , Tumor Necrosis Factor-alpha/metabolism , Cigarette Smoking/adverse effects , NF-kappa B/metabolism , Rats, Wistar , Lung , Pneumonia/chemically induced , Pneumonia/prevention & control , Pulmonary Emphysema/chemically induced , Pulmonary Emphysema/prevention & control , Pulmonary Emphysema/metabolism , Oxidative Stress , Signal Transduction , Nicotiana/toxicity , Inflammation/chemically induced , Inflammation/prevention & control , Inflammation/metabolism , Anti-Inflammatory Agents/pharmacology , Emphysema/metabolism , Emphysema/pathology , ChromatinABSTRACT
Introduction: Pathophysiological changes secondary to cirrhosis predispose patients of chronic liver disease to develop various electrolyte disturbances which have a significant impact on morbidity, mortality, and prognosis of these patients. This study aims to estimate the level of electrolyte disturbance and its association with the severity, complication, and outcome in chronic liver disease patients attending a hospital in the Kumaon region of Uttarakhand. Methods: Our study was a hospital-based cross-sectional study conducted on 100 chronic liver disease patients at the OPD/IPD Department of Medicine, Dr. Sushila Tiwari Hospital, Haldwani, Uttarakhand, from January 2020 to September 2021. Results: Hyponatremia was observed in 49% of the patients, hypokalemia in 30%, and hypocalcemia in 16% of the patients. The electrolyte levels were similar irrespective of the disease severity and presence of complications. The sodium and potassium levels had a significant association with the outcomes. Conclusion: Hyponatremia was the commonest electrolyte disturbance seen in the study patients. No significant association was observed between the electrolyte and severity of the disease and complications.
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Ribosome biogenesis, a multi-step process involving transcription, modification, folding and processing of rRNA, is the major consumer of cellular energy. It involves sequential assembly of ribosomal proteins (RP)s via more than 200 ribogenesis factors. Unlike model organisms where transcription of rRNA and RP genes slows down during stress, in Entamoeba histolytica, pre-rRNA synthesis continues, and unprocessed pre-rRNA accumulates. Northern hybridization from different spacer regions depicted the accumulation of unprocessed intermediates during stress. To gain insight into the vast repertoire of ribosome biogenesis factors and understand the major components playing role during stress we computationally identified ribosome biogenesis factors in E. histolytica. Of the â¼279 Saccharomyces cerevisiae proteins, we could only find 188 proteins in E. histolytica. Some of the proteins missing in E. histolytica were also missing in humans. A number of proteins represented by multiple genes in S. cerevisiae had a single copy in E. histolytica. Interestingly E. histolytica lacked mitochondrial ribosome biogenesis factors and had far less RNase components compared to S. cerevisiae. Transcriptomic studies revealed the differential regulation of ribosomal factors both in serum starved and RRP6 down-regulation conditions. These included the NEP1 and TSR3 proteins that chemically modify 18S-rRNA. Pre-rRNA precursors accumulate upon downregulation of the latter proteins in S. cerevisiae and humans. These data reveal the major factors that regulate pre-rRNA processing during stress in E. histolytica and provide the first complete repertoire of ribosome biogenesis factors in this early-branching protist.
Subject(s)
Alkyl and Aryl Transferases , Entamoeba histolytica , Saccharomyces cerevisiae Proteins , Alkyl and Aryl Transferases/metabolism , Humans , RNA Precursors/genetics , RNA Precursors/metabolism , RNA Processing, Post-Transcriptional , RNA, Ribosomal/genetics , RNA, Ribosomal, 18S/genetics , Ribosomes/genetics , Ribosomes/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins/genetics , TranscriptomeABSTRACT
INTRODUCTION: Nerium oleander is an eminent source of structurally diverse cardiac glycosides (CGs), plays a prominent role in the treatment of heart failure, and inhibits the proliferation of cancer cell lines. CGs exert their cardiotonic action by binding to the extracellularly exposed recognition sites on Na+ /K+ -ATPase, an integral membrane protein that establishes the electrochemical gradient of Na+ and K+ ions across the plasma membrane. OBJECTIVE: We aimed to quantitatively determine CGs and their seasonal variation in leaf and stem samples of N. oleander utilizing UHPLC-ESI-MS/MS techniques. METHODS: The UHPLC-ESI-MS/MS analytical method was developed utilizing multiple reaction monitoring (MRM) mode. The Waters BEH C18 (150 mm × 2.1 mm, 1.7 µm) column was used with a 22-min linear gradient consisting of acetonitrile and 5 mM ammonium acetate buffer. RESULTS: In total 21 CGs were quantitatively determined in the seasonal leaf and stem samples of N. oleander along with the absolute quantitation of the three chemical markers odoroside H (244.8 µg/g), odoroside A (231.4 µg/g), and oleandrin (703.9 µg/g). The season-specific accumulation of chemical markers was observed in the order of predominance odoroside A (summer season, stem), odoroside H (winter season, stem), and oleandrin (rainy season, leaf). Besides this, the remaining 18 CGs were relatively quantified in the same samples. CONCLUSION: The developed method is simple and reliable and can be used for the identification and quantification of multiple CGs in N. oleander.
Subject(s)
Cardiac Glycosides , Nerium , Cardiac Glycosides/analysis , Chromatography, High Pressure Liquid/methods , Seasons , Tandem Mass SpectrometryABSTRACT
BACKGROUND: Osteoporosis is an asymptomatic bone disorder leading to altered bone microarchitecture, mineralization and strength. Musa paradisiaca has been reported to have antioxidant and anti-inflammatory effects in various diseases. Its impact on postmenopausal osteoporosis has not been investigated yet. PURPOSE: The intention of the current study was to evaluate the bone regeneration and osteoprotective potential of extract and fraction of M. paradisiaca flower in ovariectomized (Ovx) Sprague Dawley (SD) rats, a model of post-menopausal bone loss. The study also aims to identify osteogenic compounds from active fraction. METHODS: Ethanolic extract (MFE) and butanolic fraction (MFE-Bu) from flower of M. paradisiaca were prepared and their efficacy was tested in rat femur osteotomy model at different doses. Effective dose from both extract (250 mg/kg) and fraction (50 mg/kg) were taken for study in osteopenic bone loss model. PTH was taken as reference standard (20 µg/kg/twice a week). Bones were harvested at autopsy for dynamic and static histomorphometry. Serum was collected for ELISA. Pure compounds were isolated from butanolic fraction (MFE-Bu), and were assessed for their osteogenic effect. RESULTS: MFE and MFE-Bu were observed for their potential in bone healing and prevention of bone loss. Both MFE and MFE-Bu promoted new bone regeneration at injury site as assessed by microCT and calcein dye labeling studies. These also led to restoration of bone microarchitecture deteriorated as a result of osteopenia and improved bone biomechanical properties. Extract as well as the fraction exhibited dual bone anabolic and anti-resorptive properties where they elevated serum procollagen type I N-terminal propeptide (P1NP), a bone formation marker and suppressed serum C-telopeptide of type I collagen (CTX-1), a bone resorption marker. As many as four osteogenic compounds were isolated from MFE-Bu. Oleracein-E was found to be the most potent osteogenic agent based on osteoblast differentiation, mineralization assays, qPCR and protein expression studies. CONCLUSION: Our studies demonstrates that ethanolic extract from the flower of M. paradisiaca and its butanolic fraction exhibit dual osteogenic and anti-resorptive potential, and have an advantage over PTH which though promotes bone formation but is also bone catabolic in nature.
Subject(s)
Bone Diseases, Metabolic , Musa , Animals , Bone Density , Flowers , Humans , Osteogenesis , Ovariectomy , Plant Extracts/pharmacology , Rats , Rats, Sprague-DawleyABSTRACT
Ultraperformance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) is an economical and indispensable tool in natural product research to investigate novel metabolites, biomarker discovery, chemical diversity exploration, and structure elucidation. In this study, the structural analysis of 38 naturally occurring cardiac glycosides (CGs) in various tissues of Nerium oleander was achieved by the extensive use of mass spectrometry. The chemical diversity of CGs was described on the basis of characteristic MS/MS fragmentation patterns, accurate mass measurement, and published scientific information on CGs from Nerium oleander. It was observed that only six genins, viz., Δ16anhydrogitoxigenin, Δ16adynerigenin, gitoxigenin, oleandrigenin, digitoxigenin, and adynerigenine, produce 38 diverse chemical structures of CGs. Among them, 20 were identified as diastereomers having a difference in a sugar (l-oleandrose, ß-d-diginose, and ß-d-sarmentose) unit. However, the differentiation of diastereomeric CGs was not possible by only MS/MS fragments. Thus, the diastereomer's chromatographic elution order was assigned on the basis of the relative retention time (RRt) of two reference standards (odoroside A and oleandrin) among their diastereomers. Besides this, the in-source fragmentation of CGs and the MS/MS of m/z 325 and 323 disaccharide daughter ions also exposed the intrinsic structure information on the sugar units. The daughter ions m/z 162, 145, 113, 95, and 85 in MS/MS spectra indicated the abundance of l-oleandrose, ß-d-diginose, and ß-d-sarmentose sugars. At the same time, m/z 161, 143, 129, and 87 product ions confirmed the presence of a ß-d-digitalose unit. As a result, the UPLC-ESI/TQD system was successfully utilized for the structure characterization of CGs in Nerium oleander tissues.
Subject(s)
Cardiac Glycosides/chemistry , Chromatography, High Pressure Liquid/methods , Nerium/chemistry , Tandem Mass Spectrometry/methods , Cardenolides/analysis , Cardenolides/chemistry , Cardiac Glycosides/analysis , Digitoxigenin/analysis , Digitoxigenin/chemistry , Molecular Structure , StereoisomerismABSTRACT
Emerging observations suggest that ribosomal proteins (RPs) play important extra-ribosomal roles in maintenance of cellular homeostasis. However, the mechanistic insights into these processes have not been extensively explored, especially in pathogenic bacteria. Here, we present our findings on potential extra-ribosomal functions of Mycobacterium tuberculosis (Mtb) RPs. We observed that Mtb RpsB and RpsQ are differentially localized to cell wall fraction in M. tuberculosis (H37Rv), while their M. smegmatis (Msm) homologs are primarily cytosolic. Cellular fractionation of ectopically expressed Mtb RPs in surrogate host (M. smegmatis) also shows their association with cell membrane/cell wall without any gross changes in cell morphology. M. smegmatis expressing Mtb RpsB exhibited altered redox homeostasis, decreased drug-induced ROS, reduced cell wall permeability and increased tolerance to various proteotoxic stress (oxidative stress, SDS and starvation). Mtb RpsB expression was also associated with increased resistance specifically towards Isoniazid, Ethionamide and Streptomycin. The enhanced drug tolerance was specific to Mtb RpsB and not observed upon ectopic expression of M. smegmatis homolog (Msm RpsB). Interestingly, C-terminus deletion in Mtb RpsB affected its localization and reversed the stress-resilient phenotypes. We also observed that M. tuberculosis (H37Rv) with upregulated RpsB levels had higher intracellular survival in macrophage. All these observations hint towards existence of moonlighting roles of Mtb RpsB in imparting stress resilience to mycobacteria. This work open avenues for further exploration of alternative pathways associated with fitness and drug tolerance in mycobacteria.
Subject(s)
Bacterial Proteins/physiology , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/metabolism , Ribosomal Proteins/physiology , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/chemistry , Cell Membrane/metabolism , Cell Wall/metabolism , Cytosol/metabolism , Drug Tolerance/genetics , Humans , Lipids/analysis , Macrophages/metabolism , Macrophages/microbiology , Mutant Proteins/chemistry , Mutant Proteins/physiology , Mycobacterium smegmatis/drug effects , Mycobacterium smegmatis/growth & development , Mycobacterium smegmatis/metabolism , Oxidation-Reduction , Oxidative Stress/genetics , Permeability , Reactive Oxygen Species/metabolism , Ribosomal Proteins/chemistry , Ribosomes/chemistry , THP-1 CellsABSTRACT
T-complex protein-1 (TCP1) is a chaperonin protein known to fold various proteins like actin and tubulin. In Leishmania donovani only one subunit of TCP1 that is gamma subunit (LdTCP1γ) has been functionally characterized. It not only performs ATP dependent protein folding but is also essential for survival and virulence. The present work demonstrates that LdTCP1γ also has a role in miltefosine resistance. Overexpression of LdTCP1γ in L. donovani promastigotes results in decreased sensitivity of parasites towards miltefosine, while single-allele replacement mutants exhibited increased sensitivity as compared to wild-type promastigotes. This response was specific to miltefosine with no cross-resistance to other drugs. The LdTCP1γ-mediated drug resistance was directly related to miltefosine-induced apoptotic death of the parasite, as was evidenced by 2 to 3-fold decrease in cell death parameters in overexpressing cells and >2-fold increase in single-allele replacement mutants. Further, deciphering the mechanism revealed that resistance of overexpressing cells was associated with efficient ROS neutralization due to increased levels of thiols and upregulation of cytosolic tryparedoxin peroxidase (cTxnPx). Further, modulation of LdTCP1γ expression in parasite also modulates the levels of proinflammatory cytokine (TNF-α) and anti-inflammatory cytokine (IL-10) of the host macrophages. The study provides evidence for the involvement of a chaperonin protein LdTCP1γ in the protection against miltefosine induced oxidative damage and reveals the fundamental role of LdTCP1γ in parasite biology.
Subject(s)
Chaperonins/genetics , Drug Resistance , Leishmania donovani/pathogenicity , Macrophages/parasitology , Phosphorylcholine/analogs & derivatives , Animals , Cell Line , Chaperonins/metabolism , Interleukin-10/metabolism , Leishmania donovani/drug effects , Leishmania donovani/genetics , Macrophages/cytology , Macrophages/immunology , Mice , Mutation , Oxidative Stress/drug effects , Peroxidases/metabolism , Phosphorylcholine/pharmacology , Protozoan Proteins/genetics , Protozoan Proteins/metabolism , Reactive Oxygen Species/metabolism , Sulfhydryl Compounds/metabolism , Tumor Necrosis Factor-alpha/metabolism , Up-RegulationABSTRACT
BACKGROUND: Promoter motifs in Entamoeba histolytica were earlier analysed using microarray data with lower dynamic range of gene expression. Additionally, previous transcriptomic studies did not provide information on the nature of highly transcribed genes, and downstream promoter motifs important for gene expression. To address these issues we generated RNA-Seq data and identified the high and low expressing genes, especially with respect to virulence potential. We analysed sequences both upstream and downstream of start site for important motifs. RESULTS: We used RNA-Seq data to classify genes according to expression levels, which ranged six orders of magnitude. Data were validated by reporter gene expression. Virulence-related genes (except AIG1) were amongst the highly expressed, while some kinases and BspA family genes were poorly expressed. We looked for conserved motifs in sequences upstream and downstream of the initiation codon. Following enrichment by AME we found seven motifs significantly enriched in high expression- and three in low expression-classes. Two of these motifs (M4 and M6) were located downstream of AUG, were exclusively enriched in high expression class, and were mostly found in ribosomal protein, and translation-related genes. Motif deletion resulted in drastic down regulation of reporter gene expression, showing functional relevance. Distribution of core promoter motifs (TATA, GAAC, and Inr) in all genes revealed that genes with downstream motifs were not preferentially associated with TATA-less promoters. We looked at gene expression changes in cells subjected to growth stress by serum starvation, and experimentally validated the data. Genes showing maximum up regulation belonged to the low or medium expression class, and included genes in signalling pathways, lipid metabolism, DNA repair, Myb transcription factors, BspA, and heat shock. Genes showing maximum down regulation belonged to the high or medium expression class. They included genes for signalling factors, actin, Ariel family, and ribosome biogenesis factors. CONCLUSION: Our analysis has added important new information about the E. histolytica transcriptome. We report for the first time two downstream motifs required for gene expression, which could be used for over expression of E. histolytica genes. Most of the virulence-related genes in this parasite are highly expressed in culture.
Subject(s)
Entamoeba histolytica/pathogenicity , Gene Expression Profiling/methods , Virulence Factors/genetics , Entamoeba histolytica/genetics , Gene Expression Regulation, Neoplastic , Gene Regulatory Networks , Promoter Regions, Genetic , Sequence Analysis, RNA , Whole Genome SequencingABSTRACT
The 3'-5' exoribonuclease Rrp6 is a key enzyme in RNA homeostasis involved in processing and degradation of many stable RNA precursors, aberrant transcripts, and noncoding RNAs. We previously have shown that in the protozoan parasite Entamoeba histolytica, the 5'-external transcribed spacer fragment of pre-rRNA accumulates under serum starvation-induced growth stress. This fragment is a known target of degradation by Rrp6. Here, we computationally and biochemically characterized EhRrp6 and found that it contains the catalytically important EXO and HRDC domains and exhibits exoribonuclease activity with both unstructured and structured RNA substrates, which required the conserved DEDD-Y catalytic-site residues. It lacked the N-terminal PMC2NT domain for binding of the cofactor Rrp47, but could functionally complement the growth defect of a yeast rrp6 mutant. Of note, no Rrp47 homologue was detected in E. histolytica Immunolocalization studies revealed that EhRrp6 is present both in the nucleus and cytosol of normal E. histolytica cells. However, growth stress induced its complete loss from the nuclei, reversed by proteasome inhibitors. EhRrp6-depleted E. histolytica cells were severely growth restricted, and EhRrp6 overexpression protected the cells against stress, suggesting that EhRrp6 functions as a stress sensor. Importantly EhRrp6 depletion reduced erythrophagocytosis, an important virulence determinant of E. histolytica This reduction was due to a specific decrease in transcript levels of some phagocytosis-related genes (Ehcabp3 and Ehrho1), whereas expression of other genes (Ehcabp1, Ehcabp6, Ehc2pk, and Eharp2/3) was unaffected. This is the first report of the role of Rrp6 in cell growth and stress responses in a protozoan parasite.
Subject(s)
Entamoeba histolytica/enzymology , Exoribonucleases/physiology , Phagocytosis/genetics , Catalytic Domain , Cell Nucleus/enzymology , Entamoeba histolytica/growth & development , Entamoeba histolytica/pathogenicity , Erythrocytes/immunology , Exoribonucleases/deficiency , Gene Expression RegulationABSTRACT
Leishmaniasis is a major public health problem in various part of world; it has also emerged in new geographic areas and host populations. Visceral infection can remain subclinical or become symptomatic, with an acute, subacute or chronic course. Kala-azar, or visceral leishmaniasis (VL), presents as fever, pancytopenia and hypergammaglobulinaemia. The presence of splenomegaly is characteristic of VL. It may be absent in immunocompromised patients, who may present atypically. Absence of splenomegaly is rare in immunocompetent patients, though it may occur in the early stages. Atypical presentations can be challenging to the clinician. This paper presents an atypical presentation of kala-azar, with multi-organ failure in the absence of splenomegaly or fever.