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1.
Foods ; 12(19)2023 Sep 27.
Article in English | MEDLINE | ID: mdl-37835249

ABSTRACT

Diarrhoea is a considerable agent of disease and loss of life in children below age five in South Africa. Soweto, South Africa is an urban township in Johannesburg, with most of its population living in informal settlements. Informal settlements in areas such as Soweto are often impoverished communities that do not get water easily, inadequate sanitation is pervasive, and poor hygiene common (risk factors for diarrhoeal diseases). Among the age groups, infants are most vulnerable to diarrhoeal infection, mainly through the ingestion of food and water. The presence of undesirable microbiota is a food safety and health challenge. This study investigated the microbiome of infant food samples collected from formal (n = 19) and informal (n = 11) households in Soweto. A non-culture-dependent technique was used to characterise the bacterial diversity and composition of the infant food samples. The results indicated that household type did not influence microbial diversity and composition in Soweto. South Africa. Firmicutes, Proteobacteria, Cyanobacteria, and Tenericutes dominated the phyla rank in food samples from formal and informal households. Potential pathogens of public health significance, including diarrhoeal disease agents such as Salmonella spp., E. coli, and Campylobacter spp., were detected within the foods. We concluded that the infant food samples showed rich bacterial diversity, and the presence of potential pathogens of public health significance suggests a disease risk that infants may face upon consuming the foods.

2.
Environ Monit Assess ; 195(6): 783, 2023 Jun 01.
Article in English | MEDLINE | ID: mdl-37261634

ABSTRACT

This study investigated antibiotic resistance (ABR) and extended-spectrum ß-lactamases (ESBL) patterns in bacterial isolates collected from the dairy, hotel, meat, and canteen food waste samples. A total of 144 bacterial strains were collected and screened for resistance against 9 standard antibiotics belonging to three generations and ESBL production. The ABR profile of the bacterial isolates was observed against all four major antibiotic groups (aminoglycosides, ß-lactams, quinolone, and others), where resistance against cefotaxime (> 70%) and methicillin (> 50%) was high. Though the ABR pattern of strains from dairy waste (> 50%) was high against first-generation antibiotics, the strains from meat waste (> 50%) showed considerable resistance against second- and third-generation antibiotics. ESBL-producing isolates were screened (> 60%, n = 144) through primary identification tests (combined disk test and double disk synergy tests) and further confirmed through Hexa G-minus 23 and 24 and MIC E-stripe following CLSI guidelines. Genes conferring ESBL resistance blaCTX-M, blaSHV, blaOXA, blaTEM, blaKPC genes and multidrug resistance (MDR) mexF gene were detected in the selected isolates with ABR and ESBL traits. Isolates with multidrug ABR and ESBL phenotype were further genotypically identified through 16 s rRNA gene sequencing. The synergy of ABR was detected through the co-expression of ESBL and MDR in isolates with a high occurrence of ABR and ESBL. The results demonstrate the significance of food waste as a natural reservoir of ABR and ESBL-producing pathogens, highlighting the importance of resistance monitoring and its interventions.


Subject(s)
Microbiota , Refuse Disposal , beta-Lactamases/genetics , Environmental Monitoring , Anti-Bacterial Agents/toxicity , Meat , Drug Resistance, Multiple, Bacterial , Microbial Sensitivity Tests
3.
Food Sci Biotechnol ; 32(6): 863-874, 2023 May.
Article in English | MEDLINE | ID: mdl-37041804

ABSTRACT

The present study evaluated antibiotic resistance (ABR) in bacteria isolated from different food wastes viz., meat slaughterhouses, dairy and restaurants. About 120 strains isolated from the food waste were subjected to ABR screening. More than 50% of all the strains were resistant to Vancomycin, Neomycin and Methicilin, which belong to third-generation antibiotics. Two lactic acid bacteria (LAB) free of ABR were chosen to be used as starter cultures in media formulated from food waste. Food waste combination (FWC-4) was found to be on par with the nutrient broth in biomass production. The non-ABR LAB strains showed excellent probiotic properties, and in the fed-batch fermentation process, adding a nitrogen source (soya protein) enhanced the microbial biomass (3.7 g/l). Additionally, exopolysaccharide production was found to be 2.3 g/l. This study highlights the ABR incidence in food waste medium and its economic advantage for starter culture biomass production. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01222-9.

4.
J Food Biochem ; 46(11): e14331, 2022 11.
Article in English | MEDLINE | ID: mdl-36448596

ABSTRACT

The rural communities of the sub-Sahara regions in Africa are rich in diverse indigenous culinary knowledge and foods, food crops, and condiments such as roots/tubers, cereal, legumes/pulses, locust beans, and green leafy vegetables. These food crops are rich in micronutrients and phytochemicals, which have the potentials to address hidden hunger as well as promote health when consumed. Some examples of these are fermented foods such as ogi and plants such as Vernonia amygdalina (bitter leaf), Zingiber officinales (garlic), Hibiscus sabdariffa (Roselle), and condiments. Food crops from West Africa contain numerous bioactive substances such as saponins, alkaloids, tannins, phenolics, flavonoids, and monoterpenoid chemicals among others. These bioresources have proven biological and pharmacological activities due to diverse mechanisms of action such as immunomodulatory, anti-inflammatory, antipyretic, and antioxidant activities which made them suitable as candidates for nutraceuticals and pharma foods. This review seeks to explore the different processes such as fermentation applied during food preparation and food crops of West-African origin with health-promoting benefits. The different bioactive compounds present in such food or food crops are discussed extensively as well as the diverse application, especially regarding respiratory diseases. PRACTICAL APPLICATIONS: The plants and herbs summarized here are more easily accessible and affordable by therapists and others having a passion for promising medicinal properties of African-origin plants.The mechanisms and unique metabolic potentials of African food crops discussed in this article will promote their applicability as a template molecule for novel drug discoveries in treatment strategies for emerging diseases. This compilation of antiviral plants will help clinicians and researchers bring new preventive strategies in combating COVID-19 like viral diseases, ultimately saving millions of affected people.


Subject(s)
COVID-19 , Fabaceae , Hibiscus , Humans , Health Promotion , Crops, Agricultural , Africa, Western , Vegetables , Africa , Antioxidants/pharmacology
5.
Indian J Otolaryngol Head Neck Surg ; 74(Suppl 1): 26-32, 2022 Aug.
Article in English | MEDLINE | ID: mdl-36032925

ABSTRACT

Chronic Otitis Media (COM) is a major indication for tympanoplasty. It is important to predict the outcome of surgery and give proper counselling for the patient. This avoids untoward expectations. To measure the outcome of patients who underwent tympanoplasty for mucosal type of chronic otitis media (COM) using Middle ear risk index (MERI) score. Any possible correlation of MERI score with outcomes? Assess quality-of-life. Prospective analytical comparative cohort study. Sample size was 75. All patients underwent tympanoplasty for mucosal type of COM with hearing loss. The patients were categorised into mild, moderate and severe groups based on the MERI score. The hearing benefit was calculated from the pre- and post-op difference in PTA. The graft uptake status was graded. The relation between MERI score, graft status and hearing benefit were analysed and compared. QOL was assessed by COMOT-15 questionnaire. Patients with a high MERI score had lower rate of graft uptake, whereas, patients with mild MERI had greater hearing benefit and those with severe MERI had lesser hearing benefit postoperative. MERI score is a prognostic tool to predict the outcome of tympanoplasty. It has an inverse relation with graft uptake and hearing benefit. Based on MERI score, the chances for surgical success and hearing benefit could be explained to the patient to give them realistic expectations.

6.
Chemosphere ; 299: 134361, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35331747

ABSTRACT

Globally, the valorization of fish biowaste as a feedstock to recover valuable components is an emerging research and commercial interest area to achieve the SDG goals by 2030. Fish waste-derived biomolecules are increasingly finding diverse applications in food and other biotechnological fields due to their excellent chemical, structural and functional properties. The focus of this review is to highlight the conventional valorization routes and recent advancements in extraction technologies for resource recovery applications, primarily focusing on green processes. Biointensified processes involving ultrasound, microwave, sub- and supercritical fluids, pulsed electric field, high-pressure processing, and cold plasma are extensively explored as sustainable technologies for valorizing fish discards and found numerous applications in the production of functional and commercially important biomaterials. With challenges in recovering intracellular bioactive compounds, selectivity, and energy requirement concerns, conventional approaches are being relooked continuously in the quest for process intensification and sustainable production practices. Nonetheless, in the context of 'zero waste' and 'biorefinery for high-value compounds', there is immense scope for technological upgradation in these emerging alternative approaches. This work details such attempts, providing insights into the immense untapped potential in this sector.


Subject(s)
Fishes , Food , Animals
7.
Indian J Otolaryngol Head Neck Surg ; 73(4): 486-493, 2021 Dec.
Article in English | MEDLINE | ID: mdl-33842302

ABSTRACT

Covid-19 due to Sars-Cov-2 infection has reached pandemic proportion. Many healthcare workers are involved in managing both COVID-suspected and confirmed cases. It is mandatory for healthcare workers to have droplet and contact precautions by means of Personal protective equipment (PPE), facemask, face shield or eye protection. Prolonged usage of medical mask results in various adverse effects. This study is an attempt to know the common effects of prolonged face mask in healthcare workers and its resultant quality-of-life (QOL). To study the common effects of prolonged face mask and its impact on QOL of healthcare workers during the COVID 19 crisis. This was a prospective cross-sectional study conducted over 6 months among 2750 healthcare workers. A questionnaire requesting demographic details and most common side effects after prolonged usage of face mask was circulated. We also attached a short form-12 (sf-12) questionnaire to assess its impact on QOL. Out of 2750 personnel, 299 were excluded. Male preponderance was noted. Study was conducted on candidates using 3ply mask or above. Age range was between 18 and 65 years with mean age being 37.61 ± 15.23 in mask users < 5 h per day, 32.2 ± 10.02 in 5-10 h group and 30.19 ± 8.15 in 10 h group. 8.48% (n = 174) had comorbidities. QOL impacted. The complaints with face mask use definitely are troublesome with increase in severity with duration of mask usage. This definitely has a proportional impact on the healthcare workers' QOL.

8.
Food Chem ; 334: 127555, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-32711268

ABSTRACT

Conjugated linoleic acid (CLA) content of ruminant milk reported in published research papers (n = 65) from January 1995 to March 2020 around the world were analyzed to estimate the overall mean CLA value. The CLA content of ruminant milk samples was grouped according to geographical regions (Europe, South America, North America, Oceania, Asia, and Africa). The total CLA content of milk samples from cows, sheep, goats, yaks, and llama retrieved from the collected data ranged between 0.06 and 2.96% of total fatty acids. There is a wide variation of pooled estimated mean content of CLA in milk among the study regions and were highest in Oceania with 1.33% (95% confidence interval (CI): 1.16 - 1.49%) of total fatty acids. Though several factors have been reported to influence the CLA content of milk, the effect of the "geographical origin" was only considered in the present manuscript as one of the main factors in this respect.


Subject(s)
Linoleic Acids, Conjugated/analysis , Milk/chemistry , Africa , Animals , Asia , Cattle , Europe , Fatty Acids/analysis , Goats , North America , Oceania , Ruminants , Sheep , South America
9.
J Pediatr ; 218: 106-113.e3, 2020 03.
Article in English | MEDLINE | ID: mdl-31952848

ABSTRACT

OBJECTIVE: To determine the association between the fecal microbiota diversity of the infants with different disease conditions, and vitamin A supplementation, antibiotic, and deworming therapies. STUDY DESIGN: In this case-control study, the bacterial community variations and the potential pathogens were identified through 16S ribosomal RNA gene-based amplicon sequencing and quantitative insights into microbial ecology pipeline in fecal samples. The participants were South African infants (mean age, 16 ± 8 months; 17 male and 17 female) hospitalized and diagnosed with gastrointestinal, respiratory, and other diseases. RESULTS: The top phyla of the infants with respiratory disease were Proteobacteria, followed by Firmicutes, which were equally abundant in gastrointestinal disease. A significant difference in Shannon (alpha) diversity index (95% CI, 2.6-4.4; P = .008), among the microbiota of the fecal samples categorized by disease conditions, was observed. In beta diversity analysis of fecal microbiota, remarkable variations were found within the groups of deworming therapy (95% CI, 0.40-0.90; P = .033), disease conditions (95% CI, 0.44-0.86; P < .012) through unweighted and antibiotic therapy (95% CI, 0.20-0.75; P = .007), vitamin A intake (95% CI, 0.10-0.80; P < .033) and disease conditions (95% CI, 0.10-0.79; P = .006) through weighted UniFrac distances. The candidate pathogen associated with the disease groups were identified through analysis of the composition of microbiomes analysis. CONCLUSIONS: This study provides preliminary evidence for the fecal microbiome-derived dysbiosis signature and pathobiome concept that may be observed in young children during illness.


Subject(s)
Dysbiosis/microbiology , Gastrointestinal Diseases/microbiology , Gastrointestinal Microbiome , Respiration Disorders/microbiology , Anti-Bacterial Agents/therapeutic use , Case-Control Studies , Child, Preschool , Feces/microbiology , Female , Hospitalization , Humans , Infant , Male , Principal Component Analysis , RNA, Ribosomal, 16S/metabolism , Software , South Africa , Vitamin A/therapeutic use
10.
PLoS One ; 8(6): e67634, 2013.
Article in English | MEDLINE | ID: mdl-23826330

ABSTRACT

The architecture of cellular proteins connected to form signaling pathways in response to internal and external cues is much more complex than a group of simple protein-protein interactions. Post translational modifications on proteins (e.g., phosphorylation of serine, threonine and tyrosine residues on proteins) initiate many downstream signaling events leading to protein-protein interactions and subsequent activation of signaling cascades leading to cell proliferation, cell differentiation and cell death. As evidenced by a rapidly expanding mass spectrometry database demonstrating protein phosphorylation at specific motifs, there is currently a large gap in understanding the functional significance of phosphoproteins with respect to their specific protein connections in the signaling cascades. A comprehensive map that interconnects phospho-motifs in pathways will enable identification of nodal protein interactions that are sensitive signatures indicating a disease phenotype from the physiological hemostasis and provide clues into control of disease. Using a novel phosphopeptide microarray technology, we have mapped endogenous tyrosine-phosphoproteome interaction networks in breast cancer cells mediated by signaling adaptor protein GRB2, which transduces cellular responses downstream of several RTKs through the Ras-ERK signaling cascade. We have identified several previously reported motif specific interactions and novel interactions. The peptide microarray data indicate that various phospho-motifs on a single protein are differentially regulated in various cell types and shows global downregulation of phosphoprotein interactions specifically in cells with metastatic potential. The study has revealed novel phosphoprotein mediated signaling networks, which warrants further detailed analysis of the nodes of protein-protein interaction to uncover their biomarker or therapeutic potential.


Subject(s)
Biomarkers, Tumor/metabolism , Breast Neoplasms/metabolism , GRB2 Adaptor Protein/metabolism , Phosphopeptides/metabolism , Phosphoproteins/metabolism , Breast Neoplasms/pathology , Female , Humans , Microarray Analysis , Phosphorylation , Protein Binding , Protein Interaction Maps , Tumor Cells, Cultured
11.
Arzneimittelforschung ; 59(5): 254-62, 2009.
Article in English | MEDLINE | ID: mdl-19537527

ABSTRACT

Safety pharmacological studies need to be performed according to ICH S7A Guidelines for finished formulations that substantially alter the pharmacokinetics and/or pharmacodynamics of the active substance in comparison to formulations previously tested (i. e. through active excipients such as penetration enhancers, liposomes, and other changes such as polymorphous system). In the present study, amorphous formulation of celecoxib (CAS 169590-42-5), a new patented formulation with altered pharmacokinetic profile was investigated in comparison with the standard crystalline celecoxib (CEL) for its undesirable pharmacodynamic effects using certain safety pharmacological studies. The effects of the new formulation on vital functions using safety pharmacology core battery like central nervous system (CNS) (functional observation battery, locomotor activity, and motor coordination) and cardiovascular system (CVS) (blood pressure, heart rate and QT interval) were investigated in laboratory rodents. In addition, supplementary safety pharmacology study on gastrointestinal system (GIT) (gastric injury potential, gastric secretion) was also carried out. Oral administration of a single dose of the amorphous celecoxib formulation (CF) varying of 50, 150 and 500 mg/kg was studied in comparison with vehicle treated control and crystalline celecoxib in animals. The maximum tolerated dose (MTD) was identified by administration of insufferable doses of amorphous formulation, extended up to 2000 mg/kg during the experiments on physiological parameters. There were no CNS and GIT safety concerns raised with respect to use of CF except the arrythmogenic risk associated with QT interval prolongation upon the high dose of CF.


Subject(s)
Cyclooxygenase 2 Inhibitors/adverse effects , Pyrazoles/adverse effects , Sulfonamides/adverse effects , Animals , Behavior, Animal/drug effects , Blood Pressure/drug effects , Celecoxib , Chemistry, Pharmaceutical , Cyclooxygenase 2 Inhibitors/administration & dosage , Electrocardiography/drug effects , Gastric Mucosa/drug effects , Gastric Mucosa/metabolism , Guinea Pigs , Heart Rate/drug effects , Motor Activity/drug effects , Postural Balance/drug effects , Pyrazoles/administration & dosage , Rats , Rats, Sprague-Dawley , Stomach Ulcer/chemically induced , Stomach Ulcer/pathology , Sulfonamides/administration & dosage
12.
Epilepsy Behav ; 14(1): 48-53, 2009 Jan.
Article in English | MEDLINE | ID: mdl-18952198

ABSTRACT

Thyrotropin-releasing hormone (TRH) and its analogs have a number of neurobiological functions and therapeutic uses in disorders of the central nervous system. In this study, the newly synthesized TRH analogs were evaluated for central nervous system activity in pentobarbital-induced sleeping in mice. The most potent TRH analog (L-pGlu-(2-propyl)-L-His-L-ProNH(2) coded as NP-647) was evaluated for its antiepileptic potential in various seizure models in mice in comparison with TRH. Intravenous pretreatment with NP-647 (10 and 20 micromol/kg body wt) significantly delayed the onset and reduced the frequency of convulsions in the pentylenetetrazole model, but not in the maximum electroshock seizure model. Also, it was found to be protective against picrotoxin- and kainic acid-induced seizures. However, NP-647 did not significantly affect theophylline-induced seizures. Further study of the effect of NP-647 on locomotor activity and a functional observational battery revealed that it did not significantly exhibit any undesirable effects as compared with vehicle and TRH. NP-647 did not significantly affect cerebral blood flow, whereas the native peptide TRH markedly increased cerebral blood flow. Furthermore, NP-647 exerted antiepileptic activity without significantly altering plasma thyroid-stimulating hormone levels and mean arterial blood pressure. This suggests that NP-647 is more selective for central nervous system activity and devoid of hormonal and cerebrovascular system effects. In contrast, TRH exhibited cardiac and endocrine effects as marked by significant elevation in mean arterial blood pressure and plasma thyroid-stimulating hormone levels. This study demonstrates that NP-647 has potential antiepileptic activity devoid of undesirable effects and, thus, can be exploited for the prevention and treatment of epilepsy.


Subject(s)
Anticonvulsants/pharmacology , Anticonvulsants/therapeutic use , Thyrotropin-Releasing Hormone/analogs & derivatives , Thyrotropin-Releasing Hormone/pharmacology , Animals , Anticonvulsants/toxicity , Behavior, Animal/drug effects , Blood Pressure/drug effects , Cardiovascular System/drug effects , Central Nervous System Stimulants/pharmacology , Cerebrovascular Circulation/drug effects , Convulsants/antagonists & inhibitors , Electroshock , Hypnotics and Sedatives/antagonists & inhibitors , Hypnotics and Sedatives/pharmacology , Kainic Acid/antagonists & inhibitors , Male , Mice , Motor Activity/drug effects , Pentylenetetrazole/antagonists & inhibitors , Picrotoxin/antagonists & inhibitors , Rats , Rats, Wistar , Seizures/chemically induced , Seizures/prevention & control , Sleep/drug effects , Theophylline/antagonists & inhibitors , Thyrotropin/blood , Thyrotropin-Releasing Hormone/therapeutic use , Thyrotropin-Releasing Hormone/toxicity
13.
PLoS One ; 3(8): e2877, 2008 Aug 06.
Article in English | MEDLINE | ID: mdl-18682802

ABSTRACT

Protein phosphorylation mediates many critical cellular responses and is essential for many biological functions during development. About one-third of cellular proteins are phosphorylated, representing the phosphor-proteome, and phosphorylation can alter a protein's function, activity, localization and stability. Tyrosine phosphorylation events mediated by aberrant activation of Receptor Tyrosine Kinase (RTK) pathways have been proven to be involved in the development of several diseases including cancer. To understand the systems biology of RTK activation, we have developed a phosphor-proteome focused on tyrosine phosphorylation events under insulin and EGF signaling pathways using the PhosphoScan technique coupled with high-throughput mass spectrometry analysis. Comparative proteomic analyses of all these tyrosine phosphorylation events revealed that around 70% of these pY events are conserved in human orthologs and paralogs. A careful analysis of published in vivo tyrosine phosphorylation events from literature and patents revealed that around 38% of pY events from Drosophila proteins conserved on 185 human proteins are confirmed in vivo tyrosine phosphorylation events. Hence the data are validated partially based on available reports, and the credibility of the remaining 62% of novel conserved sites that are unpublished so far is very high but requires further follow-up studies. The novel pY events found in this study that are conserved on human proteins could potentially lead to the discovery of drug targets and biomarkers for the detection of various cancers and neurodegenerative diseases.


Subject(s)
Drosophila/enzymology , Drosophila/genetics , Proteome , Receptor Protein-Tyrosine Kinases/metabolism , Animals , Conserved Sequence , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Epidermal Growth Factor/pharmacology , Epidermal Growth Factor/physiology , ErbB Receptors/genetics , ErbB Receptors/metabolism , Humans , Insulin/pharmacology , Insulin/physiology , Neoplasms/genetics , Neurodegenerative Diseases/genetics , Phosphopeptides/genetics , Phosphoproteins/genetics , Protein-Tyrosine Kinases/metabolism , Signal Transduction/physiology , Species Specificity
14.
Mol Biol Cell ; 18(10): 4190-9, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17699602

ABSTRACT

The control of gene expression by the mitogen-activated protein (MAP) kinase extracellular signal-regulated kinase (ERK) requires its translocation into the nucleus. In Drosophila S2 cells nuclear accumulation of diphospho-ERK (dpERK) is greatly reduced by interfering double-stranded RNA against Drosophila importin-7 (DIM-7) or by the expression of integrin mutants, either during active cell spreading or after stimulation by insulin. In both cases, total ERK phosphorylation (on Westerns) is not significantly affected, and ERK accumulates in a perinuclear ring. Tyrosine phosphorylation of DIM-7 is reduced in cells expressing integrin mutants, indicating a mechanistic link between these components. DIM-7 and integrins localize to the same actin-containing peripheral regions in spreading cells, but DIM-7 is not concentrated in paxillin-positive focal contacts or stable focal adhesions. The Corkscrew (SHP-2) tyrosine phosphatase binds DIM-7, and Corkscrew is required for the cortical localization of DIM-7. These data suggest a model in which ERK phosphorylation must be spatially coupled to integrin-mediated DIM-7 activation to make a complex that can be imported efficiently. Moreover, dpERK nuclear import can be restored in DIM-7-deficient cells by Xenopus Importin-7, demonstrating that ERK import is an evolutionarily conserved function of this protein.


Subject(s)
Cell Nucleus/metabolism , Drosophila Proteins/metabolism , Drosophila melanogaster/cytology , Drosophila melanogaster/metabolism , Extracellular Signal-Regulated MAP Kinases/metabolism , Integrin alpha Chains/metabolism , Karyopherins/metabolism , Animals , Cell Movement/drug effects , Cell Nucleus/drug effects , Cell Nucleus/enzymology , Cytoplasm/drug effects , Cytoplasm/enzymology , Drosophila melanogaster/drug effects , Drosophila melanogaster/enzymology , Focal Adhesions/drug effects , Insulin/pharmacology , Models, Biological , Mutation/genetics , Phosphoproteins/metabolism , Phosphorylation/drug effects , Phosphotyrosine/metabolism , Protein Transport/drug effects , Protein Tyrosine Phosphatases, Non-Receptor/metabolism , Xenopus
15.
Hum Mol Genet ; 15(4): 543-53, 2006 Feb 15.
Article in English | MEDLINE | ID: mdl-16399795

ABSTRACT

Mutations in the PTPN11 gene, which encodes the protein tyrosine phosphatase SHP-2, causes Noonan syndrome (NS), an autosomal dominant disorder with pleomorphic developmental abnormalities. Certain germline and somatic PTPN11 mutations cause leukemias. Mutations have gain-of-function (GOF) effects with the commonest NS allele, N308D, being weaker than the leukemia-causing mutations. To study the effects of disease-associated PTPN11 alleles, we generated transgenic fruitflies with GAL4-inducible expression of wild-type or mutant csw, the Drosophila orthologue of PTPN11. All three transgenic mutant CSWs rescued a hypomorphic csw allele's eye phenotype, documenting activity. Ubiquitous expression of two strong csw mutant alleles were lethal, but did not perturb development from some CSW-dependent receptor tyrosine kinase pathways. Ubiquitous expression of the weaker N308D allele caused ectopic wing veins, identical to the EGFR GOF phenotype. Epistatic analyses established that csw(N308D)'s ectopic wing vein phenotype required intact EGF ligand and receptor, and that this transgene interacted genetically with Notch, DPP and JAK/STAT signaling. Expression of the mutant csw transgenes increased RAS-MAP kinase activation, which was necessary but not sufficient for transducing their phenotypes. The findings from these fly models provided hypotheses testable in mammalian models, in which these signaling cassettes are largely conserved. In addition, these fly models can be used for sensitized screens to identify novel interacting genes as well as for high-throughput screening of therapeutic compounds for NS and PTPN11-related cancers.


Subject(s)
Drosophila Proteins/genetics , Genes, Dominant/genetics , Intracellular Signaling Peptides and Proteins/genetics , Mutation , Noonan Syndrome/genetics , Protein Tyrosine Phosphatases/genetics , Signal Transduction/genetics , Animals , Animals, Genetically Modified , Disease Models, Animal , Drosophila , Drosophila Proteins/metabolism , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Noonan Syndrome/metabolism , Protein Tyrosine Phosphatase, Non-Receptor Type 11 , Protein Tyrosine Phosphatases/metabolism
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