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  • 1
    Publication Date: 2014-01-22
    Description: Trehalose-6-phosphate phosphatase (TPP) catalyzes the final step in the biosynthesis of the anti-stress sugar trehalose. An 82 kDa TPP enzyme was isolated from Candida utilis with 61% yield and 43-fold purification. The protein sequence, determined by N-terminal sequencing and MALDI-TOF analysis, showed significant homology with known TPP sequences from related organisms. The full length gene sequence of TPP of Candida utilis was identified using rapid amplification of cDNA ends - PCR reaction (RACE-PCR). The gene was cloned and expressed in E. coli BL21. Recombinant TPP enzyme was isolated using affinity chromatography. CD spectroscopy and steady state fluorescence revealed that the structural and conformational aspects were identical in both native and recombinant forms. The biochemical properties of the two forms were also similar. K m was determined to be ∼0.8 mM. Optimum temperature and pH was found to be 30 °C and 8.5 respectively. Activity was dependent on the presence of divalent cations and inhibited by metal chelators. Methylation mediated regulation of TPP enzyme and its effect on the overall survival of the organism under stress were investigated. The results indicated that enhancement of TPP activity by methylation at the Cysteine residues increased resistance of Candida cells against thermal stress. This work involves extensive investigations towards understanding the physico-chemical properties of the first TPP enzyme from any yeast strain. The mechanism by which methylation regulates its activity has also been studied. A correlation between regulation of trehalose synthesis and survivability of the organism under thermal stress was established. J. Cell. Physiol. 9999: XX–XX, 2014. © 2014 Wiley Periodicals, Inc.
    Electronic ISSN: 1097-4652
    Topics: Biology , Medicine
    Published by Wiley
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  • 2
    Publication Date: 2013-10-17
    Description: A divergent synthesis of siphonarienal, siphonarienone, and pectinatone has been achieved from a common precursor 4 , which was synthesized by using an enzymatic desymmetrization approach. The major key steps involved were Grignard reaction, Wittig reaction, Evans ' asymmetric alkylation, and base-catalyzed cyclization.
    Print ISSN: 0018-019X
    Electronic ISSN: 1522-2675
    Topics: Chemistry and Pharmacology
    Published by Wiley
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  • 3
    Publication Date: 2013-09-22
    Description: [1]  Structural evolution of monsoon clouds in the core monsoon region of India has been examined using multi-sensor data. Invigoration of warm clouds above 4.5 km (occurring in only 15.4% days of the last 11 monsoon seasons) is associated with a transition from negative to positive normalized rainfall anomaly. Cloud top pressure reduces with an increase in aerosol optical depth at a higher rate of invigoration in drier condition (characterized by large fraction of absorbing aerosols) than wet condition. Cloud effective radius for warm clouds does not show any significant change with an increase in aerosol concentration in presence of high liquid water path, probably due to strong buffering role of meteorology. The structural evolution of monsoon clouds is influenced by both dynamic and microphysical processes that prolong the cloud lifetime, resulting in infrequent rainfall. Our results call for improved representation of aerosol and cloud vertical structures in the climate models to resolve this issue.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 4
    Publication Date: 2014-01-25
    Description: Myocardial infarction (MI) is defined as cardiac cell death due to prolonged ischemia. Although necrotic cell death was considered to be solely responsible for myocyte death during MI, it was recently revealed that apoptosis also plays its part in this death process. Our laboratory has recently shown that endoplasmic reticulum (ER) stress-induced apoptosis is the predominant route for apoptosis during MI and the conventional mitochondrial pathway is bypassed by activation of a small heat shock protein α-crystallin B (CRYAB). Since CRYAB is a direct target of P38 mitogen-activated protein kinase (MAPK) cascade, we were prompted to check the role of P38 MAPK in 20-week-old male Wister rats immediately after infarct formation. Interestingly, parallel activation of mitochondrial apoptotic pathway with an increase in ER stress-induced apoptotic load was observed along with decreased activation of CRYAB and Nrf2 (a pro-survival protein activated in response to ER stress) in MI rats treated with SB203580, a specific inhibitor of P38α and P38β compared to the MI alone. As a cumulative effect, this inhibitor treatment also resulted in significant increase in the levels of caspase3 activity and TUNEL positivity, the end point apoptotic markers. Furthermore, SB203580-treated hypoxic adult cardiomyocytes showed formation of desmin aggregates which were previously associated with impaired cardiac function. Thus, this study shows for the first time the precise mechanism by which P38 MAPK plays a pro-survival role and confers protection of cardiomyocytes, during infarct formation. J. Cell. Physiol. © 2014 Wiley Periodicals, Inc.
    Electronic ISSN: 1097-4652
    Topics: Biology , Medicine
    Published by Wiley
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  • 5
    Publication Date: 2012-07-07
    Description: The effect of upwelling events, storm water discharge, and local circulation on phytoplankton blooms in the central California and Southern California Bight (SCB) coastal zones was analyzed using 10+ years (1997–2007) of remotely sensed surface chlorophyll concentration (CHL, derived from SeaWiFS ocean color), sea surface temperature, and modeled freshwater discharge. Analysis of variability and factors associated with phytoplankton blooms was conducted using the offshore extension of zones of CHL 〉 5 mg m−3; this method excludes terrestrial interference that complicates the use of ocean color to investigate phytoplankton blooms in coastal waters. In the SCB, blooms were most frequent in spring and associated with the spring transition to an upwelling regime. Along the Central Coast, blooms persisted from spring to autumn during seasonal intensification of upwelling. Offshore CHL extensions showed a significant positive trend during 1997–2007, with maxima in 2000–2001 and 2005–2006 that coincided with higher than normal frequency of upwelling events. Upwelling was found to be a major factor driving phytoplankton blooms, although the standard upwelling index derived from large-scale atmospheric circulation was decoupled from the frequencies of both upwelling events and phytoplankton blooms. Areas of longer residence time associated with natural boundaries between coastal ocean regions had more extensive and persistent blooms. The influence of storm water discharge on offshore CHL extension appeared to be limited to areas in close proximity to major river mouths. These “hot spots” were also co-located with ocean outfalls of Publicly Owned Treatment Works (POTW) discharge and, in some cases, longer residence time of coastal waters.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 6
    Publication Date: 2012-04-04
    Description: Pointillistic based super-resolution techniques, such as photoactivated localization microscopy (PALM), involve multiple cycles of sequential activation, imaging, and precise localization of single fluorescent molecules. A super-resolution image, having nanoscopic structural information, is then constructed by compiling all the image sequences. Because the final image resolution is determined by the localization precision of detected single molecules and their density, accurate image reconstruction requires imaging of biological structures labeled with fluorescent molecules at high density. In such image datasets, stochastic variations in photon emission and intervening dark states lead to uncertainties in identification of single molecules. This, in turn, prevents the proper utilization of the wealth of information on molecular distribution and quantity. A recent strategy for overcoming this problem is pair-correlation analysis applied to PALM. Using rigorous statistical algorithms to estimate the number of detected proteins, this approach allows the spatial organization of molecules to be quantitatively described.
    Print ISSN: 0265-9247
    Electronic ISSN: 1521-1878
    Topics: Biology , Medicine
    Published by Wiley
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  • 7
    Publication Date: 2012-04-15
    Description: Pointillistic based super-resolution techniques, such as photoactivated localization microscopy (PALM), involve multiple cycles of sequential activation, imaging, and precise localization of single fluorescent molecules. A super-resolution image, having nanoscopic structural information, is then constructed by compiling all the image sequences. Because the final image resolution is determined by the localization precision of detected single molecules and their density, accurate image reconstruction requires imaging of biological structures labeled with fluorescent molecules at high density. In such image datasets, stochastic variations in photon emission and intervening dark states lead to uncertainties in identification of single molecules. This, in turn, prevents the proper utilization of the wealth of information on molecular distribution and quantity. A recent strategy for overcoming this problem is pair-correlation analysis applied to PALM. Using rigorous statistical algorithms to estimate the number of detected proteins, this approach allows the spatial organization of molecules to be quantitatively described.
    Print ISSN: 0265-9247
    Electronic ISSN: 1521-1878
    Topics: Biology , Medicine
    Published by Wiley
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  • 8
    Publication Date: 2013-12-08
    Description: A series of compositions with general stoichiometry Ca 1− x Zr 1− x Nd 2 x Ti 2 O 7 has been prepared by high-temperature solid-state reaction of component oxides and characterized by powder X-ray diffraction and electron probe for microanalyses (EPMA). The phase fields in CaZrTi 2 O 7 – Nd 2 Ti 2 O 7 system and distribution of ions in different phases have been determined. Four different phase fields, namely monoclinic zirconolite, cubic perovskite, cubic pyrochlore, and monoclinic Nd 2 Ti 2 O 7 structure types are observed in this system. The 4M-polytype of zirconolite structure is stabilized by substitution of Nd 3+ ion. The addition of Nd 3+ ions form a cubic perovskite structure-type phase and thus observed in all the compositions with 0.05 ≤  x  ≤ 0.80. Cubic pyrochlore structure-type phase is observed as a coexisting phase in the nominal composition with 0.20 ≤  x  ≤ 0.90. Only a subtle amounts of Ca 2+ and Zr 4+ are incorporated into the perovskite-type Nd 2 Ti 2 O 7 structure. EPMA analyses on different coexisting phases revealed that the pyrochlore and perovskite phases have Nd 3+ -rich compositions.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 9
    Publication Date: 2013-11-07
    Description: We present here, for the first time, comprehensive depth specific (near surface to 1800m) oxygen isotope (δ 18 O) dataset of 175 water samples collected from 22 different locations in the Bay of Bengal (BoB) during July-August, 2009 and December-January, 2012-13. The study is aimed to constrain the water mass parameters using oxygen isotope and salinity. Four water masses are identified on the basis of temperature-salinity relationship- (a) Bay of Bengal water (BoBW;0-50m), (b) Mixed zone (MZ; 60-120m) (c) Indonesian throughflow (ITF; 200-500m) and (d) Indian Ocean Deep water (IDW; 600-1800m). Our study shows- (1) δ 18 O-salinity correlation (slope = 0.15 ± 0.01; intercept = -4.58 ± 0.24; r 2 = 0.85; n = 54) for the BoBW is found to be consistent with surface BoB water reported earlier, (2) relatively lower correlation (r 2 = 0.24; n = 47) in underlying mixed zone suggesting mixing of various water masses (3) significant linear correlation between δ 18 O and salinity in IDW (r 2 = 0.70) indicating depleted less saline water from southern hemisphere spread upto 18 º N, and (4) vertical profiles at various sampling locations showing a continuous enrichment of δ 18 O (0.6-0.8‰) within top 60-100 meters irrespective of their proximity to coastline. In conjunction with a sharp decrease in Δ 14 C data below the same depth zone (60-100 m) as reported earlier, we suggest the δ 18 O value reaches to its acme at a zone of mixing between younger BoBW and relatively older ITF. This preliminary study indicates oxygen isotope and salinity together can be used to identify different water masses in the BoB.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 10
    Publication Date: 2013-09-01
    Description: ABSTRACT Sequelae of chronic lead (Pb 2+ ) toxicity includes anemia that is partially due to early death of erythrocytes characterized by excess accumulation of ROS and downregulation of antioxidant system causing oxidative stress and externalization of phosphatidylserine. In this study, pathophysiological based therapeutic application of garlic was evaluated against erythrocyte death. Results suggest that garlic administration prevents oxidative stress, restored the antioxidant balance in erythrocytes of Pb 2+ exposed mice. Moreover, in vitro studies revealed that activity of both scramblase and aminophospholipid translocase could be changed by modifying the critical sulfhydryl groups in presence of dithiothreitol during Pb 2+ exposure. Data also indicated that garlic treatment in Pb 2+ exposed mice exhibited sharp decline in PS exposure and increase in erythrocyte membrane thiol group followed by increase in aminophospholipid translocase activity and decline in scramblase activity. Findings indicated that garlic has the ability to restore the lifespan of erythrocytes during Pb 2+ exposure. © 2013 Wiley Periodicals, Inc. Environ Toxicol, 2013.
    Print ISSN: 1520-4081
    Electronic ISSN: 1522-7278
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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