1,426 research outputs found
Magnetic Resonance Imaging and Spectroscopy using Squid Detection
Magnetic Resonance Imaging (MRI), with its unique capability to image soft tissues, has become one of the most powerful nondestructive diagnostic tools in medicine. MRI is still a developing methodology in non-medical nondestructive evaluation (NDE); this is because solids with their broader nuclear magnetic resonance (NMR) linewidths are more difficult to image than biological tissue. However, recently MRI has been attracting increasing interest in a number of areas where the NMR linewidth is not as serious a problem. These include fluid flow determination in materials including porous media [1], detecting defects in ceramics still in the green (unfired) state [2], and the evaluation of polymers such as rubber and other elastomers [3]. Superconducting Quantum Interference Devices, or SQUIDs, with their great sensitivity and broad bandwidth have the potential to enhance MRI in both medical and non-medical applications
Multi-serotype pneumococcal nasopharyngeal carriage prevalence in vaccine naïve Nepalese children, assessed using molecular serotyping.
Invasive pneumococcal disease is one of the major causes of death in young children in resource poor countries. Nasopharyngeal carriage studies provide insight into the local prevalence of circulating pneumococcal serotypes. There are very few data on the concurrent carriage of multiple pneumococcal serotypes. This study aimed to identify the prevalence and serotype distribution of pneumococci carried in the nasopharynx of young healthy Nepalese children prior to the introduction of a pneumococcal conjugate vaccine using a microarray-based molecular serotyping method capable of detecting multi-serotype carriage. We conducted a cross-sectional study of healthy children aged 6 weeks to 24 months from the Kathmandu Valley, Nepal between May and October 2012. Nasopharyngeal swabs were frozen and subsequently plated on selective culture media. DNA extracts of plate sweeps of pneumococcal colonies from these cultures were analysed using a molecular serotyping microarray capable of detecting relative abundance of multiple pneumococcal serotypes. 600 children were enrolled into the study: 199 aged 6 weeks to <6 months, 202 aged 6 months to < 12 months, and 199 aged 12 month to 24 months. Typeable pneumococci were identified in 297/600 (49.5%) of samples with more than one serotype being found in 67/297 (20.2%) of these samples. The serotypes covered by the thirteen-valent pneumococcal conjugate vaccine were identified in 44.4% of samples containing typeable pneumococci. Application of a molecular serotyping approach to identification of multiple pneumococcal carriage demonstrates a substantial prevalence of co-colonisation. Continued surveillance utilising this approach following the introduction of routine use of pneumococcal conjugate vaccinates in infants will provide a more accurate understanding of vaccine efficacy against carriage and a better understanding of the dynamics of subsequent serotype and genotype replacement
Synthesis of Non-Natural Cofactor Analogs of S-adenosyl-L-methionine Using Methionine Adenosyltransferase
The present disclosure relates to the synthesis of non-natural analogs of S-adenosyl-L-methionine (SAM) and/or of Se-adenosyl- L-methionine (SeAM) by reacting a methionine analog and adenosine triphosphate (ATP) in the presence of at least one methionine adenosyltransferase (MAT), and to use thereof with downstream SAM and/or SeAM utilizing enzymes.
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A systematic review of evidence to inform HIV prevention interventions among men who have sex with men in Europe.
An estimated 42% of all newly diagnosed HIV cases in Europe in 2013 were transmitted during sex between men. This review was performed to identify and describe studies evaluating the efficacy and effectiveness of HIV prevention interventions among men who have sex with men (MSM), in relation to implementation data from European settings. A systematic search was performed individually for 24 interventions.Data were extracted from studies including efficacy or implementation data from European settings,appraised for efficacy, implementation and plausibility, and assigned a grade (1-4) according to the Highest Attainable Standard of Evidence (HASTE)framework. Four interventions (condom use, peer outreach,peer-led groups, and using universal coverage of antiretroviral treatment and treatment as prevention)were assigned the highest HASTE grade, 1. Another four interventions were assigned 2a for probable recommendation, including voluntary counseling and testing for HIV, using condom-compatible lubricant,using post-exposure prophylaxis, and individual counselling for MSM living with HIV. In addition, seven interventions were assigned a grade of 2b, for possible recommendation. Encouragingly, 15 interventions were graded to be strongly, probably or possibly recommended.In the relatively resource-rich European setting, there is an opportunity to provide global leadership with regard to the regional scale-up of comprehensive HIV prevention interventions for MSM
Loop Dynamics of Thymidine Diphosphate-Rhamnose 3\u27-\u3cem\u3eO\u3c/em\u3e-Methyltransferase (CalS11), an Enzyme in Calicheamicin Biosynthesis
Structure analysis and ensemble refinement of the apo-structure of thymidine diphosphate (TDP)-rhamnose 3\u27-O-methyltransferase reveal a gate for substrate entry and product release. TDP-rhamnose 3\u27-O-methyltransferase (CalS11) catalyses a 3\u27-O-methylation of TDP-rhamnose, an intermediate in the biosynthesis of enediyne antitumor antibiotic calicheamicin. CalS11 operates at the sugar nucleotide stage prior to glycosylation step. Here, we present the crystal structure of the apo form of CalS11 at 1.89 Å resolution. We propose that the L2 loop functions as a gate facilitating and/or providing specificity for substrate entry or promoting product release. Ensemble refinement analysis slightly improves the crystallographic refinement statistics and furthermore provides a compelling way to visualize the dynamic model of loop L2, supporting the understanding of its proposed role in catalysis
Spore Forming Actinobacterial Diversity of Cholistan Desert Pakistan: Polyphasic Taxonomy, Antimicrobial Potential and Chemical Profiling
Background: Actinobacteria are famous for the production of unique secondary metabolites that help in controlling the continuously emerging drug resistance all over the globe. This study aimed at the investigation of an extreme environment the Cholistan desert, located in southern Punjab, Pakistan, for actinobacterial diversity and their activity against methicillin resistant Staphylococcus aureus (MRSA). The Cholistan desert is a sub-tropical and arid ecosystem with harsh environment, limited rainfall and low humidity. The 20 soil and sand samples were collected from different locations in the desert and the actinobacterial strains were selectively isolated. The isolated strains were identified using a polyphasic taxonomic approach including morphological, biochemical, physiological characterization, scanning electron microscopy (SEM) and by 16S rRNA gene sequencing.
Results: A total of 110 desert actinobacterial strains were recovered, which were found to be belonging to 3 different families of the order Actinomycetales, including the family Streptomycetaceae, family Pseudonocardiaceae and the family Micrococcaceae. The most frequently isolated genus was Streptomyces along with the genera Pseudonocardia and Arthrobacter. The isolated strains exhibited promising antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA) with zone of inhibition in the range of 9–32 mm in antimicrobial screening assays. The chemical profiling by thin layer chromatography, HPLC-UV/Vis and LC-MS analysis depicted the presence of different structural classes of antibiotics.
Conclusion: The study revealed that Cholistan desert harbors immense actinobacterial diversity and most of the strains produce structurally diverse bioactive secondary metabolites, which are a promising source of novel antimicrobial drug candidates
Fibroblast Growth Factor 21 Has a Diverse Role in Energetic and Reproductive Physiological Functions of Female Beef Cattle
Fibroblast growth factor 21 (FGF21) has been identified in multiple mammalian species as a molecular marker of energy metabolism while also providing negative feedback to the gonads. However, the role of FGF21 in regulating the energetic and reproductive physiology of beef heifers and cows has yet to be characterized. Herein, we investigated the temporal concentrations of FGF21 in female beef cattle from the prepubertal period to early lactation. Circulating concentrations of FGF21, non-esterified fatty acids, plasma urea nitrogen, glucose, and progesterone were assessed. Ultrasonography was employed to determine the onset of puberty and resumption of postpartum ovarian cyclicity as well as to measure backfat thickness. Finally, cows and calves underwent the weigh-suckle-weigh technique to estimate rate of milk production. We have revealed that FGF21 has an expansive role in the physiology of female beef cattle, including pubertal onset, adaptation to nutritional transition, rate of body weight gain, circulating markers of metabolism, and rate of milk production. In conclusion, FGF21 plays a role in physiological functions in beef cattle that can be applied to advance the understanding of basic scientific processes governing the nutritional regulation of reproductive function but also provides a novel means for beef cattle producers to select parameters of financial interest
Antibacterial Activity of Endophytic Actinomycetes Isolated from the Medicinal Plant \u3cem\u3eVochysia divergens\u3c/em\u3e (Pantanal, Brazil)
Endophytic actinomycetes from medicinal plants produce a wide diversity of secondary metabolites (SM). However, to date, the knowledge about endophytes from Brazil remains scarce. Thus, we analyzed the antimicrobial potential of 10 actinomycetes isolated from the medicinal plant Vochysia divergens located in the Pantanal sul-mato-grossense, an unexplored wetland in Brazil. Strains were classified as belonging to the Aeromicrobium, Actinomadura, Microbacterium, Microbispora, Micrococcus, Sphaerisporangium, Streptomyces, and Williamsia genera, through morphological and 16S rRNA phylogenetic analyzes. A susceptibility analysis demonstrated that the strains were largely resistant to the antibiotics oxacillin and nalidixic acid. Additionally, different culture media (SG and R5A), and temperatures (28 and 36°C) were evaluated to select the best culture conditions to produce the active SM. All conditions were analyzed for active metabolites, and the best antibacterial activity was observed from metabolites produced with SG medium at 36°C. The LGMB491 (close related to Aeromicrobium ponti) extract showed the highest activity against methicillin-resistant Staphylococcus aureus (MRSA), with a MIC of 0.04 mg/mL, and it was selected for SM identification. Strain LGMB491 produced 1-acetyl-β-carboline (1), indole-3-carbaldehyde (2), 3-(hydroxyacetyl)-indole (4), brevianamide F (5), and cyclo-(L-Pro-L-Phe) (6) as major compounds with antibacterial activity. In this study, we add to the knowledge about the endophytic community from the medicinal plant V. divergens and report the isolation of rare actinomycetes that produce highly active metabolites
Bioactivity and Metabolomics Profiling of Endophytic Actinobacteria Isolated from Roots of the Medicinal Plants Dominant in South Asian Region
Background: Plant-derived endophytic actinobacteria are the center of attention due to their capacity to produce diverse antimicrobial and anticancer compounds and their metabolites influence plant growth.Methods: In this study, 40 endophytic actinobacteria strains were isolated from the roots of eight medicinal plants used as folk medicine in South Asian region. The isolates were characterized morphologically, biochemically and physiologically and the genus level identification of the selected strains was done by 16SrRNA gene sequencing. In small scale cultivation (50ml broth), the isolates were grown in A-medium to prepare the crude extracts. These crude extracts were subsequently evaluated for their antimicrobial, anticancer and antioxidant activity and the metabolomics profile of each of the extract was determined by TLC and HPLC-UV/MS.Results: The taxonomic studies showed that the isolates belong to the group actinobacteria based on their morphological and physiological characteristics and the 16SrRNA gene sequencing of the selected strains identified the genera including Streptomyces, Micromonospora and Nocardia. Cumulatively,53% of extracts exhibited anti-Gram-(+) activity,47% exhibited anti-Gram-(-) activity,32% exhibited antifungal activity and 30% were cytotoxic to PC3 and A549 cancer cell lines and most of the extracts have shown antioxidant activity greater than 50%. The metabolomics analysis predicted the presence of an array of low molecular weight metabolites and indicated the promising isolates in collection for further studies for novel bioactive metabolite isolation and structure elucidation.Conclusion: Overall the study provides an overview of the endophytic actinobacteria residing in the roots of the selected medicinal plants prevalent in south Asian region and their potential to produce the medicinally and biotechnologically useful compounds.Keywords: Endophytic Actinobacteria; Metabolomic Profiling; Natural Products; Antimicrobial Compounds; Anticancer Compounds Â
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