83 research outputs found

    Androgenic and Estrogenic Response of Green Mussel Extracts from Singapore’s Coastal Environment Using a Human Cell-Based Bioassay

    Get PDF
    In the last decade, evidence of endocrine disruption in biota exposed to environmental pollutants has raised serious concern. Human cell-based bioassays have been developed to evaluate induced androgenic and estrogenic activities of chemical compounds. However, bioassays have been sparsely applied to environmental samples. In this study we present data on sex hormone activities in the green mussel, Perna viridis, in Singapore’s coastal waters. P. viridis is a common bioindicator of marine contamination, and this study is a follow-up to an earlier investigation that reported the presence of sex hormone activities in seawater samples from Singapore’s coastal environment. Specimens were collected from eight locations around the Singapore coastline and analyzed for persistent organic pollutants (POPs) and heavy metals. Tissue extracts were then screened for activities on androgen receptors (ARs) and estrogen receptors (ER-α and ER-β) using a reporter gene bio-assay based on a HeLa human cell line. Mussel extracts alone did not exhibit AR activity, but in the presence of the reference androgenic hormone dihydrotestosterone (DHT), activities were up to 340% higher than those observed for DHT alone. Peak activities were observed in locations adjacent to industrial and shipping activities. Estrogenic activities of the mussel extract both alone and in the presence of reference hormone were positive. Correlations were statistically investigated between sex hormone activities, levels of pollutants in the mussel tissues, and various biological parameters (specimen size, sex ratio, lipid and moisture content). Significant correlations exist between AR activities, in the presence of DHT, and total concentration of POPs (r = 0.725, p < 0.05)

    Analysis of the comparative study on flower pigments with phenylalanine ammonia-lyase activity in orchid plants

    Get PDF
    Background: Orchidaceae plants have been one of the most important industrial products in the agricultural industry around the world. Since the flower petals have eye-catching pigments, they can be used as cut flowers in addition to being potted flowers. Objective: The key pigments found in orchid flower petals were studied, as well as their relationships to phenylalanine ammonia-lyase (PAL) activity. Results: Total anthocyanin content of six different orchids’ petals was determined specthrophotometrically and the value ranged from 0 mg/g (in Dendrobium Shavin white) to 2.128 mg/g (in Mokara Aranda). The petals with vivid colour have a high amount of anthocyanin content, while, they have a high amount of chlorophyll content for those with pale colour. Total anthocyanin content was found to be the highest when compare to β-carotene and chlorophyll content. PAL behaviour was found to be significantly positive associated with anthocyanin content in correlation analysis. Conclusion: The results indicate the potential for PAL enzyme as a biomarker for flower colour in orchids

    Comparison on phytochemical constituents in the patchouli oil of in vitro and ex vitro pogostemon cablin leaves

    Get PDF
    Pogostemon cablin (patchouli) is a medicinal herb well known for its essential oil derived from the leaves. Patchouli oil shows excellent base note in fragrance industries for its fixatives properties and its patchouli alcohol (patchoulol) is used as quality indicator for its oil. However, the P. cablin is the only commercial source of patchoulol and cannot be obtained synthetically in the laboratory. Higher demand in the production of its essential oil gave a significant contribution for in vitro grown P.cablin to meet the market supply for industries. Hence, in this study, the essential oil in both in vitro and ex vitro P.cablin were extracted from its leaves by means of hydrodistillation method and its phytochemical constituents were identified and compared using Gas Chromatography Mass Spectrometry. The yield and quality of its essential oil from both in vitro and ex vitro P.cablin’s leaves were investigated. In vitro patchouli essential oil extraction gaves higher yield (40 ml) than the ex vitro patchouli essential oil (26 ml) under similar condition for hydrodistillation. Six major components were identified through GC-MS and was compared between two samples which are β- patchoulene, Caryophyllene, α- guaiene, α- cedrene, α- bulnesene and Patchouli alcohol. The patchoulol, which is the main constituents that is important in fixative had doubled (42.18 %) in the in vitro P.cablin essential oil compared to ex vitro (29.24%). This finding was reflected based on the peak area percentage of each substance through GC-MS. Other constituents in the in vitro P.cablin were found still competitive to the ex vitro in slightly lower values. Overall, in vitro P.cablin showed higher yield and quality compared to the ex vitro grown P.cablin

    A prospective comparison of UK and Malaysian patients with irritable bowel syndrome in secondary care

    Get PDF
    Background The prevalence of irritable bowel syndrome (IBS) is now known to be similar in various geographical regions, but there has been no study directly comparing characteristics of patients with IBS between populations. Aims To evaluate clinical and psychological differences between adults with IBS seen in secondary care in the United Kingdom (UK) and Malaysia. Methods Age- and sex-matched patients with IBS from a single centre in the UK (Leeds) and two centres in Malaysia (Kuala Lumpur and Kota Bharu), who fulfilled Rome III criteria, were recruited prospectively. Demographic characteristics and gastrointestinal and psychological symptoms were compared between both groups. Results A total of 266 (133 UK and 133 Malaysian) age- and sex-matched patients with Rome III IBS were recruited (mean age: 45.1 years Malaysia, vs. 46.5 years UK; 57.9% female). UK patients were more likely to consume alcohol than Malaysian patients (54.1% vs. 10.5%, p < 0.001). Compared with Malaysian patients, UK patients had more frequent abdominal pain, abdominal bloating, meal-related symptoms (p < 0.001 for all), higher symptom scores (mean 268.0 vs 166.0; p < 0.001), greater limitation of activities due to IBS (p = 0.007) and were more likely to report abnormal anxiety scores (p < 0.001). Higher perceived stress (mean 21.3 vs. 19.1, p = 0.014) and gastrointestinal symptom-specific anxiety scores (mean 50.8 vs. 43.0, p < 0.001) were also observed in UK patients. Finally, UK patients had higher somatoform symptom-reporting scores (mean 8.9 vs. 6.9, p < 0.001). Conclusions IBS is more severe and is associated with a higher level of psychological symptoms in the UK compared with Malaysian patients in secondary care

    Risk factors for anxiety and depression among pregnant women during COVID-19 pandemic-Results of a web-based multinational cross-sectional study

    Get PDF
    Objective To assess risk factors for anxiety and depression among pregnant women during the COVID-19 pandemic using Mind-COVID, a prospective cross-sectional study that compares outcomes in middle-income economies and high-income economies. Methods A total of 7102 pregnant women from 12 high-income economies and nine middle-income economies were included. The web-based survey used two standardized instruments, General Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire-9 (PHQ-9). Result Pregnant women in high-income economies reported higher PHQ-9 (0.18 standard deviation [SD], P < 0.001) and GAD-7 (0.08 SD, P = 0.005) scores than those living in middle-income economies. Multivariate regression analysis showed that increasing PHQ-9 and GAD-7 scales were associated with mental health problems during pregnancy and the need for psychiatric treatment before pregnancy. PHQ-9 was associated with a feeling of burden related to restrictions in social distancing, and access to leisure activities. GAD-7 scores were associated with a pregnancy-related complication, fear of adverse outcomes in children related to COVID-19, and feeling of burden related to finances. Conclusions According to this study, the imposed public health measures and hospital restrictions have left pregnant women more vulnerable during these difficult times. Adequate partner and family support during pregnancy and childbirth can be one of the most important protective factors against anxiety and depression, regardless of national economic status

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

    Get PDF
    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Gestational diabetes mellitus and retinal microvasculature.

    Get PDF
    BACKGROUND: Small-vessel dysfunction may be an important consequence of chronic hyperglycemia. We examined the association between gestational diabetes mellitus (GDM), a state of transient hyperglycemia during pregnancy, and retinal microvascular changes in pregnant women at 26-28 weeks of pregnancy. METHODS: A total of 1136 pregnant women with singleton pregnancies were recruited during their first trimester at two major Singapore maternity hospitals in an on-going birth cohort study. Participants underwent an oral glucose tolerance test and retinal imaging at 26-28 weeks gestation (n = 542). We used the 1999 World Health Organization (WHO) criteria to define GDM: ≥7.0 mmol/L for fasting glucose and/or ≥7.8 mmol/L for 2-h post-glucose. Retinal microvasculature was measured using computer software (Singapore I Vessel Analyzer, SIVA version 3.0, Singapore Eye Research Institute, Singapore) from the retinal photographs. RESULTS: In a multiple linear regression model adjusting for age, ethnicity and maternal education, mothers with GDM had narrower arteriolar caliber (-1.6 μm; 95% Confidence Interval [CI]: -3.1 μm, -0.2 μm), reduced arteriolar fractal dimension (-0.01 Df; 95% CI: -0.02 Df, -0.001 Df;), and larger arteriolar branching angle (1.8°; 95% CI: 0.3°, 3.3°) than mothers without GDM. After further adjusting for traditional risks of GDM, arteriolar branching angle remained significantly larger in mothers with GDM than those without GDM (2.0°; 95% CI: 0.5°, 3.6°). CONCLUSIONS: GDM was associated with a series of retinal arteriolar abnormalities, including narrower caliber, reduced fractal dimension and larger branching angle, suggesting that transient hyperglycemia during pregnancy may cause small-vessel dysfunction

    In vitro antimicrobial activity of natural toxins and animal venoms tested against Burkholderia pseudomallei

    Get PDF
    BACKGROUND: Burkholderia pseudomallei are the causative agent of melioidosis. Increasing resistance of the disease to antibiotics is a severe problem in treatment regime and has led to intensification of the search for new drugs. Antimicrobial peptides are the most ubiquitous in nature as part of the innate immune system and host defense mechanism. METHODS: Here, we investigated a group of venoms (snakes, scorpions and honey bee venoms) for antimicrobial properties against two strains of Gram-negative bacteria Burkholderia pseudomallei by using disc-diffusion assay for in vitro susceptibility testing. The antibacterial activities of the venoms were compared with that of the isolated L-amino acid oxidase (LAAO) and phospholipase A(2 )(PLA(2)s) enzymes. MICs were determined using broth dilution method. Bacterial growth was assessed by measurement of optical density at the lowest dilutions (MIC 0.25 mg/ml). The cell viability was measured using tetrazolium salts (XTT) based cytotoxic assay. RESULTS: The studied venoms showed high antimicrobial activity. The venoms of C. adamanteus, Daboia russelli russelli, A. halys, P. australis, B. candidus and P. guttata were equally as effective as Chloramphenicol and Ceftazidime (30 μg/disc). Among those tested, phospholipase A(2 )enzymes (crotoxin B and daboiatoxin) showed the most potent antibacterial activity against Gram-negative (TES) bacteria. Naturally occurring venom peptides and phospholipase A(2 )proved to possess highly potent antimicrobial activity against Burkholderia pseudomallei. The XTT-assay results showed that the cell survival decreased with increasing concentrations (0.05–10 mg/mL) of Crotalus adamanteus venom, with no effect on the cell viability evident at 0.5 mg/mL. CONCLUSION: This antibacterial profile of snake venoms reported herein will be useful in the search for potential antibacterial agents against drug resistant microorganisms like B. pseudomallei

    2′-O Methylation of Internal Adenosine by Flavivirus NS5 Methyltransferase

    Get PDF
    RNA modification plays an important role in modulating host-pathogen interaction. Flavivirus NS5 protein encodes N-7 and 2′-O methyltransferase activities that are required for the formation of 5′ type I cap (m7GpppAm) of viral RNA genome. Here we reported, for the first time, that flavivirus NS5 has a novel internal RNA methylation activity. Recombinant NS5 proteins of West Nile virus and Dengue virus (serotype 4; DENV-4) specifically methylates polyA, but not polyG, polyC, or polyU, indicating that the methylation occurs at adenosine residue. RNAs with internal adenosines substituted with 2′-O-methyladenosines are not active substrates for internal methylation, whereas RNAs with adenosines substituted with N6-methyladenosines can be efficiently methylated, suggesting that the internal methylation occurs at the 2′-OH position of adenosine. Mass spectroscopic analysis further demonstrated that the internal methylation product is 2′-O-methyladenosine. Importantly, genomic RNA purified from DENV virion contains 2′-O-methyladenosine. The 2′-O methylation of internal adenosine does not require specific RNA sequence since recombinant methyltransferase of DENV-4 can efficiently methylate RNAs spanning different regions of viral genome, host ribosomal RNAs, and polyA. Structure-based mutagenesis results indicate that K61-D146-K181-E217 tetrad of DENV-4 methyltransferase forms the active site of internal methylation activity; in addition, distinct residues within the methyl donor (S-adenosyl-L-methionine) pocket, GTP pocket, and RNA-binding site are critical for the internal methylation activity. Functional analysis using flavivirus replicon and genome-length RNAs showed that internal methylation attenuated viral RNA translation and replication. Polymerase assay revealed that internal 2′-O-methyladenosine reduces the efficiency of RNA elongation. Collectively, our results demonstrate that flavivirus NS5 performs 2′-O methylation of internal adenosine of viral RNA in vivo and host ribosomal RNAs in vitro
    corecore