85 research outputs found
T Cell responses to whole SARS Coronavirus in humans
No full textEffective vaccines should confer long-term protection against future outbreaks of severe acute respiratory syndrome (SARS) caused by a novel zoonotic coronavirus (SARS-CoV) with unknown animal reservoirs. We conducted a cohort study examining multiple parameters of immune responses to SARS-CoV infection, aiming to identify the immune correlates of protection. We used a matrix of overlapping peptides spanning whole SARS-CoV proteome to determine T cell responses from 128 SARS convalescent samples by ex vivo IFN-γ ELISPOT assays. Approximately 50% of convalescent SARS patients were positive for T cell responses, and 90% possessed strongly neutralizing Abs. Fifty-five novel T cell epitopes were identified, with spike protein dominating total T cell responses. CD8+ T cell responses were more frequent and of a greater magnitude than CD4+ T cell responses (p < 0.001).
Polychromatic cytometry analysis indicated that the virus-specific T cells from the severe group tended to be a central memory phenotype (CD27+/CD45RO+) with a significantly higher frequency of polyfunctional CD4+ T cells producing IFN-γ, TNF-α, and IL-2, and CD8+ T cells producing IFN-γ, TNF-α, and CD107a (degranulation), as compared with the mild-moderate group. Strong T cell responses correlated significantly (p < 0.05) with higher neutralizing Ab. The serum cytokine profile during acute infection indicated a significant elevation of innate immune responses. Increased Th2 cytokines were observed in patients with fatal infection. Our study provides a roadmap for the immunogenicity of SARS-CoV and types of immune responses that may be responsible for the virus clearance, and should serve as a benchmark for SARS-CoV vaccine design and evaluation
Evaluation of Total Phenolic and Antioxidant Contents of Sulfated Polysaccharide from Chnoospora minima (Hering, 1856)
No full textActive metabolites and functional ingredients of seaweeds have valuable beneficial health effects. Sulfated polysaccharides in seaweeds have been increasingly studied over the years in the pharmaceutical field, given their potential usefulness in applications such as designing of drug delivery systems for cancer and diabetes. Chnoospora minima is a brown algae belongs to family scytosiphonaceae that contains Fucoidan as its major polysaccharide constituent. This study examined the total phenol and antioxidant potential of sulfated polysaccharide isolated from Chnoospora minima. Antioxidant activities of purified sulfated polysaccharides were evaluated using 2, 2 diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and Ferrous Reducing Ability of Plasma (FRAP) assays. Total phenolic content was determined using spectrophotometric technique, based on the Folin-Ciocalteau reagent, and the values were expressed as Gallic acid equivalence. The total Phenolic content was 1.22±0.22 mg Gallic Acid Equivalence Weight (GAE)/g of dry mass. The free radical scavenging activity of the sulfated polysaccharide from Chnoospora minima revealed that the reduction of DPPH occurred in a concentration-dependent manner with high reductions occurring at the highest concentration. The radical scavenging activity of sulfated polysaccharide from Chnoospora minima was 0.32±0.22 mg/ml compared to the standard DPPH (IC50=0.0087±0.067 mg/ml). The ferrous reducing antioxidant power of C. minima was 14.24±5.47 mg Trolox equivalence (TE)/1 g of sample. According to the results, sulfated polysaccharide from Chnoospora minima showed high antioxidant thus the extract can be considered as a potential source of natural antioxidants agents.Keywords: Chnoospora minima, Sulfated Polysaccharide, Antioxidant potentialAcknowledgement: Sri Jayewardenepura University grant ASP/01/RE/SCI/2017/4
Phytochemical Analysis and Anti–Oxidant Activity of Plumbago Indica L. Root Bark
No full textRoot and root bark of Plumbago indica (family: Plumbaginaceae, common name: Rath nithul/nitol in Sinhala) is used in traditional medicine in treating numerous ailments including rheumatism, bronchitis and cancers. The previous work has focused mainly on P. zeylanica and therefore limited scientific literature is available on P. indica species. As a preliminary study, phytochemical constituents of the powdered root bark (RB) extracted with four different solvents (chloroform, n-hexane, methanol and aqueous) were examined according to standard methods. Furthermore the extracts rich with numerous phytochemicals; aqueous and methanol were subjected to further investigations. Therefore, the methanol RB extract was subjected to gas chromatography/mass spectrometry (GC/MS) analysis (Gas Chromatograph: Agilent-7890/ Mass Spectrometer: Agilent-5975; Capillary column-HP-5MS (30x0.25 mm); Oven temperature:50° C for 5 min, raised from 50 to 250° C at a rate of 2 °C/min; NIST 08 library Database).Anti-oxidant activity in both aqueous and methanol RB extracts was tested using diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Phytochemical screening of the aqueous RB extract revealed the presence of saponins, tannins, phenols and anthraquinones. Chloroform extract only had anthraquinones, unsaturated sterols and triterpenes. Similarly the methanol extract gave positive results for tannins, phenols, anthraquinones, unsaturated sterols and triterpenes while the hexane extract revealed the presence of anthraquinones, unsaturated sterols and triterpenes. GC/MS analysis confirmed the presence of fatty acids (Hexadecanoic acid methyl ester and 9-Octadecenoic acid methyl ester) as major constituents. Both extracts produced dose dependent antioxidant activity for the tested concentration series (31.25, 62.5, 125, 250, 500, and 1000 μg/ml). The IC50 values for aqueous and methanol extractions were 186.92±1.76 μg/ml and 458.01±1.57 μg/ml respectively and the positive control (ascorbic acid) was 146.07±1.09 μg/ml. According to the results, the aqueous RB extract showed high potential towards anti-oxidant activity than the methanol RB extract. Therefore, isolating and identifying the therapeutic potential of the active compounds would make a significant value to the economy of Sri Lanka.Keywords: Plumbago indica, Phytochemical screening, GC/MS analysis, Antioxidant activityAcknowledgement: Sri Jayewardenepura University grant ASP/06/RE/SCI/2016/2
Effects of Aqueous Leaf Extract of Passiflora suberosa L. on Blood Glucose Levels of Male Mice
No full textExtracts of the genes Passiflora has been shown to compromises a therapeutic value tocontrol glycemia and lipid levels. Raw leaves of Passiflora suberosa L. (Family:Passifloraceae) is used as a traditional remedy to manage diabetes. Yet, its ethnomedicalusage is not scientifically proven. The present study was conducted to examine thehypoglyceamic effect of the aqueous leaf extract (ALE) of P. suberosa, using normoglycemicmale mice. ALE was prepared and mice (n=9/group), were treated with 25, 50, 100, 200mg/kg ALE and distilled water (DW; control). Fasting and random blood glucose levels weredetermined at 1st, 3rd and 5th h post-treatment. Acute administration of 50 mg/kg of ALEsignificantly (p<0.01) reduced fasting blood glucose levels (BGL) by 10%, 20% and 24%respectively at 1st, 3rd and 5th h post treatment. Similarly, 100 mg/kg of ALE significantly(p<0.01) reduced fasting BGL at 3rd (24%) and 5th (29%) h post treatment. However, it didnot change the random BGL in non-fasted mice. To evaluate the chronic effect of ALE, 18mice (n=9) were treated orally either with 50 mg/kg of ALE or DW for 30 consecutive daysand on day 31, fasting BGL was measured after 1,3 and 5 hrs. A significant reduction infasting BGL was observed, at 1st (17%), 3rd (18%) and 5th (27%) h respectively. The samedose showed a significant (p<0.01) improvement in sucrose tolerance test (18%) after 5hours. However, ALE did not show a significant improvement in glucose tolerance testfollowing an oral glucose challenge. The findings from this study provide evidences forethnomedical usage of P. suberosa as an anti-diabetic agent in the traditional Sri Lankanmedicinal system.Keywords: Passiflora suberosa, Aqueous leaf extract, Hypoglycemia, Blood glucose leve
Green Synthesis, Characterization, and Antimicrobial Activity of Silver Nanoparticles from Brown Algae Padina Commersonii
No full textNanotechnology, which operates at the nanoscale (1-100 nm), is advancing due to the unique properties of materials exhibited at this scale, particularly increased surface area. Silver nanoparticles (AgNPs) are highly valued for their conductivity, stability, and therapeutic potential. Green synthesis offers an eco-friendly approach to nanoparticle production by utilizing biological compounds, including those found in marine algae like Padina commersonii, an edible brown algae species from the Hikkaduwa coast of Sri Lanka. The study's objective was to biosynthesize AgNPs using Padina commersonii, characterize the nanoparticles, and evaluate their antimicrobial activity. AgNPs were synthesized by combining crude methanol extract of the algae with silver nitrate. Characterization was conducted through various techniques, including UV-Vis spectroscopy, Dynamic Light Scattering (DLS), Zeta potential analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Raman spectroscopy. The colour shift from pale yellow to reddish-brown within 48 hours confirmed nanoparticle formation. UV-Vis spectrophotometry revealed a peak at 424 nm, indicating the presence of AgNPs. DLS analysis determined an average size of 73.19 nm, with a zeta potential of -21.5 mV, signifying stability. SEM images showed spherical nanoparticles with smooth surfaces, while EDX analysis confirmed 19.5% silver content by weight. XRD analysis indicated a face-centered cubic structure, and FTIR and Raman spectra identified proteins, phenolic compounds, and amines as capping agents. The synthesized AgNPs demonstrated significant antimicrobial effects against Staphylococcus aureus (12.77±0.58 mm), Escherichia coli (15.27±0.58 mm), Aspergillus niger (18.10±0.15 mm), and Candida albicans (17.43±0.57 mm), outperforming the crude extract of Padina commersonii. The antimicrobial potential of silver nanoparticles synthesized using Padina commersonii against bacterial strains Staphylococcus aureus (12.77±0.58 mm), Escherichia coli (15.27±0.58 mm), and fungal strains Aspergillus niger (18.10±0.15 mm) and Candida albicans (17.43±0.57 mm) was greater than that of the crude extract of Padina commersonii (S. aureus = 11.17±0.29 mm, E. coli=10.50±0.50mm, A. niger=12.66±0.10mm, C. albicans=15.66±0.10mm) These findings suggest that AgNPs synthesized through green methods offer a promising strategy for treating bacterial and fungal infections.
Keywords: Silver nanoparticles, Padina commersonii, Antimicrobial, Green synthesis, Characterizatio
A Novel in-silico driven Approach to Determine the Structure and Therapeutic Potential of Cystatin C from Danio rerio
No full textCystatins, a superfamily of evolutionary related proteins are classified as housekeeping proteins vital for the inhibition of Papain-like cysteine proteases. Over expression of cysteine proteases have been related to the development of diseases. These facts result in the realization of Cystatins importance as regulators of protease activity and their role in the body’s immune system. The Cystatin C protein understudy was identified from a pre-established transcriptomic database of D. rerio using the NCBI database and the NCBI-BLAST algorithm. Cystatin C belongs to the Type 2 Cystatin family and is the most powerful cysteine protease inhibitor effective against Papain like proteases. The research study aims to develop an economical in-silico based approach to analyze the structure and functionality of novel proteins with a comprehensive revelation of their clinical significance. Therefore, we report on novel in-silico tools to generate a model of the Cystatin C protein expressed by D. rerio, prove its functionality through molecular docking techniques and discover its immune potential against diseases caused by Cathepsin over expression through the use of gene-gene interaction mapping. Through the computational procedure a 99.99% accurate protein structure was predicted through homology modelling techniques followed by successful inhibition of Papain and mammalian Cathepsins B, H, L1 and S with therapeutic potential present for diseases caused by Cathepsin B and L1 overexpression. Analysis of the Cathepsin inhibition zone revealed a common binding site on the Cystatin C proteins’ surface amoung seven closely related amino acids. In conclusion D. rerio produces a Cystatin C protein that can successfully act as a cysteine protease inhibitor in addition to bearing valuable therapeutic potential. Further analysis is required to confirm its tissue specific expression, modulation under pathogenic conditions.Keywords: Danio rerio, in-silico, Protein-protein docking, Virtual screening, Therapeutic
Phytochemical Screening and Antimicrobial Activity of Extracts from Passiflora suberosa L. Leaves
No full textPlants are the basis of traditional medicine system and have been the source of many of novel drug components. Passiflora suberosa is used in Sri Lankan Ayurvedic system to treat many diseases including diabetes. The objective of the present study was to evaluate phytochemical constituent of different extracts and antimicrobial effect of methanol and aqueous extracts of leaves of P. suberosa. Aqueous, methanol, chloroform and hexane extracts of leaves of P. suberosa obtained under reflux conditions were subjected for phytochemical screening according to previously established methods. Aqueous and methanol extracts of P. suberosa leaves possessed more phytochemicals, thus those extracts were subjected for antimicrobial study which was obtained using minimum inhibition assay as determined by agar well diffusion method. Both methanol and aqueous extracts ranging from 6 μg/ml - 800 μg/ml were tested against both gram positive (Bacillus subtilis, Staphylococcus aureus and Enterococcus faecium) and gram negative bacteria (Pseudumonas aeruginosa, Salmonella typhimuriam and Escherichia cloi) while Gentamicin was used as the standarded drug. The phytochemical screening revealed the presence of saponins and anthraquinones in the chloroform extract, alkaloids, saponins, and flavonoids in the hexane extract and alkaloids, unsaturated sterols, triterpenes, saponins, flavonoids and tannins in both methanol and aqueous extracts. Proanthocyanidin, which is a potent free radical scavenger, was observed only in the aqueous extract. Further, only methanol extract was found to possess moderate activity against all the tested bacterial strains. Highest concentration (800 μg/ml) of methanol extract showed widest zone of inhibition (7 mm), indicating moderate activity against tested bacterial strains. In contrast, the aqueous extract showed poor activity against tested bacterial strains. In conclusion, results revealed the presence of bioactive natural compounds in aqueous and mehtanolic extracts that may be used in the development of pharmaceutical products. Similarly, preliminary studies on antimicrobial activity exhibited antimicrobial potential of methanol extract, which could be used as future antimicrobial sources for natural therapies, food industry.Keywords: Passiflora suberosa, Phytochemical, Antimicrobial activity, Agar well diffusio
Antioxidant and Cytotoxic Activities of Passiflora suberosa L. Leaf Extracts
No full textIn the Ayruvedic herbal system in Sri Lanka, Passiflora suberosa is used to treat many diseases including diabetes. The present study was conducted to evaluate in vitro antioxidant potential and cytotoxic activities of methanol and water extracts, obtained from P. suberosa leaves. P. suberosa leaves were powdered and extracted with methanol and water to obtain the crude extracts. Antioxidant capacity of different concentrations of aqueous and methanol extracts were determined by their ability to scavenge free radical using 1-diphenyl-2-picryl-hydrazil (DPPH) and by antihaemolytic activity. Similar concentrations were further tested for cytotoxicity using brine shrimps cytotoxicity assay. IC50 values were calculated to evaluate both antioxidant properties and toxicity of plant extracts. According to DPPH assay, IC50 values of both aqueous and methanol leaf extracts were 74.33 μg/ml and 418.67 μg/ml respectively. The IC50 value of the aqueous extract of P. suberosa leaf was significantly less than that of the standard ascorbic acid, which was found to be 166.17 μg/ml. Whereas IC50 values of antihaemolytic activity were 80.08 μg/ml and 610.25μg/ml in aqueous and methanol leaf extracts respectively. Results from brine shrimp cytotoxicity assay, showed that IC50 values for aqueous and methanol extracts of P. suberosa leaves were 60.26 μg/ml and 309.02 μg/ml respectively. The aqueous extract of P. suberosa leaves exhibited better antioxidant activity and cytotoxic activity than the methanol extract. Hence, present findings suggest that extracts of P. suberosa leaves possess applicable natural antioxidant and cytotoxic potential. Further, P. suberosa leaves possess better antioxidant activity than ascorbic acid, which is a well-established antioxidant. Hence, extracts from P. suberosa leaves can be considered as potential antioxidant and cytotoxic agents as well as imminent candidate for cancer therapy.Keywords: Passiflora suberosa, Antioxidant, Cytotoxic, IC50 value
Inaction and Impunity: Incidents of Religious Violence Targeting Christians, Muslims and Hindus (2015-2019)
No full text45p. The study is based on information provided by the National Christian Evangelical Alliance of Sri Lanka (NCEASL). It was compiled by Media Team of Verité Research. Mahoshadi Peiris was the lead researcher and author of the study. The team comprised of Mihindu Perera and Jonathan Cruse.Ethno-religious violence in Sri Lanka is a chronic and systemic problem that has continued despite successive changes in government. This study examines the key trends of incidents of violence faced by minority Christian, Muslim and Hindu groups in Sri Lanka between 2015 and 2019.
In 2015, the National Christian Evangelical Alliance of Sri Lanka and Verité Research released Silent Suppression: Restrictions on Religious Freedoms of Christians 1994-2004, a 20-year trend analysis report on ethno-religious violence.
This study build on that previous report by analysing 397 incidents of Freedom of Religion or Belief (FoRB) violations against Christians, multiple incidents of anti-Muslim riots, and discrimination against Hindu communities in the Northern and Eastern Provinces.
The findings of the study highlight a concerning trend of increased involvement of state officials as both active and passive actors in violations against minority communities. Moreover, the study finds that religious violence is sustained invariably through the action or inaction of the state
The presence of 5-HT in myenteric varicosities is not due to uptake of 5-HT released from the mucosa during dissection: use of a novel method for quantifying 5-HT immunoreactivity in myenteric ganglia
No full textAuthor version made available according to Publisher copyright policy. This is the accepted version of the following article:
Keating, D. J., Peiris, H., Kyloh, M., Brookes, S. J. H. and Spencer, N. J. (2013), The presence of 5-HT in myenteric varicosities is not due to uptake of 5-HT released from the mucosa during dissection: use of a novel method for quantifying 5-HT immunoreactivity in myenteric ganglia. Neurogastroenterology & Motility, 25: 849–853,
which has been published in final form at
http://dx.doi.org/10.1111/nmo.12189.
In addition, authors may also transmit, print and share copies with colleagues, provided that there is no systematic distribution of the submitted version, e.g. posting on a listserve, network or automated delivery
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