729 research outputs found
The site of attachment of retinal in bacteriorhodopsin. The epsilon-amino group in Lys-41 is not required for proton translocation
Chymotryptic fragments C-1 (amino acids 72-248) and C-2 (amino acids 1-71) of bacteriorhodopsin have been shown previously to reassociate so as to regenerate the native bacteriorhodopsin chromophore in lipid/detergent mixtures and to form functional proton-translocating vesicles. The fragment C-2 has now been selectively methylated with formaldehyde and sodium cyanoborohydride to give the epsilon-dimethylamino derivatives of Lys-30, 40, and 41 in 96-99% average yield. The methylated and unmethylated C-2 fragments were identical in their ability to reassociate with fragment C-1 and retinal to regenerate the bacteriorhodopsin chromophore and to form functional proton-translocating vesicles. In contrast, dimethylation of the lysine residues of the C-1 fragment gave a derivative which did not form an active complex with unmethylated C-2. We conclude that the epsilon-amino group in Lys-41 is not required for Schiff's base formation with retinal at any step in the light-driven proton-translocation cycle
Electronic Instrumentation
Contains research objectives and reports on four research projects.National Institutes of Health (Grant 1 505 FR07047-01
Association between self-rating depression scores and total ghrelin and adipokine serum levels in a large population-based sample
Background: Ghrelin and the adipokines leptin and adiponectin have been suggested to be involved in mood and anxiety regulation and to be altered in affective disorders. However, studies investigating the association between ghrelin, leptin and adiponectin and depressive symptomatology are scarce but might contribute to a better understanding of their involvement in mood regulation. We thus aimed investigating the association between depressive symptomatology and total ghrelin as well as leptin and adiponectin serum levels in a large population-based sample. Methods: Total serum ghrelin, adiponectin and leptin levels were determined in 1666 subjects of a population-based cross-sectional study (βLIFEβ). The Center for Epidemiological Studies Depression Scale (CES-D) and the Inventory of Depressive Symptoms β Self Rating (IDS-SR) were administered. Multiple linear regression analyses were conducted to examine the association between total serum ghrelin, leptin and adiponectin and the intensity of depressive symptoms. Results: In the total sample (n = 1,092), neither ghrelin nor leptin or adiponectin serum levels showed a significant association with CES-D or IDS-SR sum scores (N = 1,092) or in depressed/non-depressed subjects. Leptin serum levels showed a significantly positive association with IDS-SR sum scores in elderly men (β₯60 years; Ξ² = 0.122, 95% CI: 0.009; 0.236; p = 0.035). Conclusion: Our study suggests that peripheral levels of ghrelin and adipokines in a cross-sectional study design might not be sufficient to measure their involvement in depression, suggesting that associations are more complex and multi-layered. Copyright Β© 2022 Wittekind, Kratzsch, Biemann, Mergl, Riedel-Heller, Witte, Villringer and Kluge
ΠΠ½Π°Π»ΠΈΠ· ΠΏΡΠΈΠΌΠ΅Π½ΠΈΠΌΠΎΡΡΠΈ ΡΠΈΡΠ»Π΅Π½Π½ΡΡ Π°Π»Π³ΠΎΡΠΈΡΠΌΠΎΠ² Π΄Π»Ρ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ² Π² ΡΠΎΠΏΠΊΠ΅ ΠΊΠΎΡΠ»Π° Ρ ΡΠΈΡΠΊΡΠ»ΠΈΡΡΡΡΠΈΠΌ ΠΊΠΈΠΏΡΡΠΈΠΌ ΡΠ»ΠΎΠ΅ΠΌ
ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
Π·Π°Π΄Π°Ρ ΡΠ²ΡΠ·Π°Π½ΠΎ Ρ ΡΠ΅ΡΠ΅Π½ΠΈΠ΅ΠΌ ΡΠΈΡΡΠ΅ΠΌ Π΄ΠΈΡΡΠ΅ΡΠ΅Π½ΡΠΈΠ°Π»ΡΠ½ΡΡ
ΡΡΠ°Π²Π½Π΅Π½ΠΈΠΉ Ρ Π±ΠΎΠ»ΡΡΠΈΠΌ ΡΠΈΡΠ»ΠΎΠΌ Π½Π΅ΠΈΠ·Π²Π΅ΡΡΠ½ΡΡ
, ΡΡΠΎ ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡ ΠΊ ΠΈΡ
ΡΠΏΡΠΎΡΠ΅Π½ΠΈΡ ΠΈ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΠΎ ΠΎΡΡΠ°ΠΆΠ°Π΅ΡΡΡ Π½Π° ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΡΠ°ΡΡΠ΅ΡΠ°. ΠΠ°Π½Π½Π°Ρ ΡΠ°Π±ΠΎΡΠ° Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½Π° Π½Π° ΠΎΡΠ΅Π½ΠΊΡ ΠΏΡΠΈΠΌΠ΅Π½ΠΈΠΌΠΎΡΡΠΈ ΡΠ΅Ρ
ΠΈΠ»ΠΈ ΠΈΠ½ΡΡ
ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
Π°Π»Π³ΠΎΡΠΈΡΠΌΠΎΠ² Π΄Π»Ρ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ² Π² ΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΊΠΎΡΠ»Π°Ρ
Ρ ΡΠΈΡΠΊΡΠ»ΠΈΡΡΡΡΠΈΠΌ ΠΊΠΈΠΏΡΡΠΈΠΌ ΡΠ»ΠΎΠ΅ΠΌModeling of various tasks related to the solution of systems of differential equations with a large number of unknowns, which leads to their simplification and, accordingly, affect the quality of the calculation. This work aims to assess the applicability of those or other mathematical algorithms to obtain a quantitative simulation of processes in power boilers with circulating fluidized bed
Mapping migrant territories as topological deformations of space
Our research uses the concept of βterritoriesβ to describe the production of migrant space. The article describes a project based in London where the everyday practice of walking is used to map migrant territories, which are conceptualized as dispersed and overlapping, causing topological deformations to the actual lived space. We interrogate these deformations through focusing on the micro-scale and the everyday, mapping them as βscapesβ and βspheres.β Using specific computational techniques, we transform the original walks into an architectural tool for investigating the fluctuations and flows of the contemporary city. In doing so, we approach territories from two distinct angles: from the geopolitical perspective of territories seen as the product of the interplay of politics, power, and space and from the biological perspective of territories seen as the primal need of all animals, including humans, for space and a certain distinction from their environment and from others
Tandem mass spectrometry data quality assessment by self-convolution
<p>Abstract</p> <p>Background</p> <p>Many algorithms have been developed for deciphering the tandem mass spectrometry (MS) data sets. They can be essentially clustered into two classes. The first performs searches on theoretical mass spectrum database, while the second based itself on <it>de novo </it>sequencing from raw mass spectrometry data. It was noted that the quality of mass spectra affects significantly the protein identification processes in both instances. This prompted the authors to explore ways to measure the quality of MS data sets before subjecting them to the protein identification algorithms, thus allowing for more meaningful searches and increased confidence level of proteins identified.</p> <p>Results</p> <p>The proposed method measures the qualities of MS data sets based on the symmetric property of b- and y-ion peaks present in a MS spectrum. Self-convolution on MS data and its time-reversal copy was employed. Due to the symmetric nature of b-ions and y-ions peaks, the self-convolution result of a good spectrum would produce a highest mid point intensity peak. To reduce processing time, self-convolution was achieved using Fast Fourier Transform and its inverse transform, followed by the removal of the "DC" (Direct Current) component and the normalisation of the data set. The quality score was defined as the ratio of the intensity at the mid point to the remaining peaks of the convolution result. The method was validated using both theoretical mass spectra, with various permutations, and several real MS data sets. The results were encouraging, revealing a high percentage of positive prediction rates for spectra with good quality scores.</p> <p>Conclusion</p> <p>We have demonstrated in this work a method for determining the quality of tandem MS data set. By pre-determining the quality of tandem MS data before subjecting them to protein identification algorithms, spurious protein predictions due to poor tandem MS data are avoided, giving scientists greater confidence in the predicted results. We conclude that the algorithm performs well and could potentially be used as a pre-processing for all mass spectrometry based protein identification tools.</p
A mass accuracy sensitive probability based scoring algorithm for database searching of tandem mass spectrometry data
<p>Abstract</p> <p>Background</p> <p>Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) has become one of the most used tools in mass spectrometry based proteomics. Various algorithms have since been developed to automate the process for modern high-throughput LC-MS/MS experiments.</p> <p>Results</p> <p>A probability based statistical scoring model for assessing peptide and protein matches in tandem MS database search was derived. The statistical scores in the model represent the probability that a peptide match is a random occurrence based on the number or the total abundance of matched product ions in the experimental spectrum. The model also calculates probability based scores to assess protein matches. Thus the protein scores in the model reflect the significance of protein matches and can be used to differentiate true from random protein matches.</p> <p>Conclusion</p> <p>The model is sensitive to high mass accuracy and implicitly takes mass accuracy into account during scoring. High mass accuracy will not only reduce false positives, but also improves the scores of true positive matches. The algorithm is incorporated in an automated database search program MassMatrix.</p
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