458 research outputs found
Stimulation of insulin secretion by 5-methylcoumarins and its sulfur analogues isolated from Clutia lanceolata Forssk
No full textClutia lanceolata Forssk. (C. lanceolata) is a medicinal plant native to sub-Saharan Africa and the Arabian Peninsula. Phytochemical investigation of the aerial parts of C. lanceolata yielded twenty-one coumarins including methylthio and methylsulfinyl-coumarins. Thirteen of these compounds are reported here for the first time, named as cluteolin A to M. The remaining eight compounds are known but have not been associated previously with C. lanceolata. The structures of the undescribed compounds were elucidated from their 2D NMR and MS spectra. Single crystal X-ray analyses confirmed the structures of eleven compounds. As, in Saudi Arabian tradition, C. lanceolata has been reported to have anti-diabetic and anti-fungal properties, the coumarins were examined for their biological activity. Seven compounds strongly enhanced the glucose-triggered release of insulin by murine pancreatic islets, with two compounds showing more than two-fold enhancement of insulin secretion, compared with the standard drug glimepiride
Compounds related to saudin and three new series of diterpenoids from clutia lanceolata
No full textClutia lanceolata is a medicinal plant native to Ethiopia and sub-Saharan Africa and to the Arabian Peninsula. It is used traditionally in Saudi Arabia for the treatment of diabetes. Previous phytochemical analysis of this species has been limited to the identification of methylthiocoumarins. Further work has led to isolation of 19 new diterpenoids in three structural classes. Their structures were established by HRMS and by a range of NMR techniques (1H, 13C, COSY, NOESY, HSQC, HMBC), with confirmation for some examples by X-ray crystallography. NOESY and 1H–1H NMR coupling constants gave the relative stereochemical configurations and conformational information, with absolute configurations being established through X-ray crystallography. One example closely related to the known hypoglycemic compound saudin (found in C. richardiana and also in C. lanceolata) and one with a different core tetracycle were found to enhance strongly the glucose-triggered release of insulin from murine pancreatic islets. Biosynthetic proposals for the three groups of new diterpenoids by alternative cyclization of a common precursor are put forward. Lanceolide P (16) is proposed as a lead compound for further development for the treatment of diabetes
akashkoppa/global-water-energy-closure: global water and energy balance closure
No full textContains data and scripts for reproducing the results of the research article titled
'Closing the Combined Water and Energy Balance of Global Watersheds from Earth Observations'
Authors: Akash Koppa1, Sarfaraz Alam1, Diego G. Miralles2, and Mekonnen Gebremichael1
1Department of Civil and Environmental Engineering, University of California, Los Angeles, CA, USA
2Hydro-Climate Extremes Lab (H-CEL), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
Corresponding author: Akash Koppa ([email protected]
Eukaryotic formylglycine-generating enzyme catalyses a monooxygenase type of reaction
No full textPeng J, Alam S, Radhakrishnan K, et al. Eukaryotic formylglycine-generating enzyme catalyses a monooxygenase type of reaction. FEBS Journal. 2015;282(17):3262-3274.C alpha-formylglycine (FGly) is the catalytic residue of sulfatases in eukaryotes. It is generated by a unique post-translational modification catalysed by the FGly-generating enzyme (FGE) in the endoplasmic reticulum. FGE oxidizes a cysteine residue within the conserved CxPxR sequence motif of nascent sulfatase polypeptides to FGly. Here we show that this oxidation is strictly dependent on molecular oxygen (O-2) and consumes 1 mol O-2 per mol FGly formed. For maximal activity FGE requires an O-2 concentration of 9% (105 mu M). Sustained FGE activity further requires the presence of a thiol-based reductant such as DTT. FGly is also formed in the absence of DTT, but its formation ceases rapidly. Thus inactivated FGE accumulates in which the cysteine pair Cys336/Cys341 in the catalytic site is oxidized to form disulfide bridges between either Cys336 and Cys341 or Cys341 and the CxPxR cysteine of the sulfatase. These results strongly suggest that the Cys336/Cys341 pair is directly involved in the O-2-dependent conversion of the CxPxR cysteine to FGly. The available data characterize eukaryotic FGE as a monooxygenase, in which Cys336/Cys341 disulfide bridge formation donates the electrons required to reduce one oxygen atom of O-2 to water while the other oxygen atom oxidizes the CxPxR cysteine to FGly. Regeneration of a reduced Cys336/Cys341 pair is accomplished in vivo by a yet unknown reductant of the endoplasmic reticulum or in vitro by DTT. Remarkably, this monooxygenase reaction utilizes O-2 without involvement of any activating cofactor
MoC Concert: Dastaa Student Band Performing Activist Songs
No full textThe band Dastaa invites you to explore the harmonious continuum between student political participation and the classical music repertoire of Bihar. Songs include Hum dekhenge, written by Faiz Ahmed Faiz [1/3], Aise dastoor ko main nahi maanta, written by Habib Jalib [2/3], Inquilab chahta hu [2/3], Ghulamiya, written by Gorakh Pandey [3/3] and Jogira sararara [3/3]. Lead singer: Shashibhushan Samad. Violin: Shairik Sengupta. Guitar: Shivam Srivastava. Associate singers: Sarfaraz Hamid, Shas..
Errors in Author Name and Author Affiliations in Reply Letter by Golding et al (Arthritis Rheumatol, May 2014)
No full text
Disposable Bioprocessing Systems
No full textWritten by a researcher with experience designing, establishing, and validating biological manufacturing facilities worldwide, this is the first comprehensive introduction to disposable systems for biological drug manufacturing. It reviews the current state of the industry; tackles questions about safety, costs, regulations, and waste disposal; and guides readers to choose disposable components that meet their needs. This practical manual covers disposable containers, mixing systems, bioreactors, connectors and transfers, controls and sensors, downstream processing systems, filling and finishing systems, and filters. The author also shares his predictions for the future, calling disposable bioprocessing technology a "game changer.
A Trimeric Proanthocyanidin from the Bark of Acacia leucophloea Willd.
No full text(-)-Fisetinidol-(4 alpha,8)-[(-)-fisetinidol-(4 alpha,6)]-(+)-catechin (1), a proanthocyanidin, was isolated from the bark of Acacia leucophloea. Its structure including absolute configuration was elucidated on the basis of spectroscopic analysis and chemical correlation. The H-1 NMR spectrum of this compound, exhibiting exceptional complex signals attributable to rotational isomerism, and the reported data were obtained at elevated temperature in methyl ether acetate form. This work provided the H-1 and C-13 NMR assignments for 1 and its rotational isomer as the free phenolic form at ambient temperature for the first time. Compound 1 showed inhibitory activity against alpha-glucosidase type IV from Bacillus stearothermophilus with the IC50 value of 102.3 mu M
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