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1
Ambrus, Árpád, e Eugenia Soboleva. "Contribution of Sampling to the Variability of Pesticide Residue Data". Journal of AOAC INTERNATIONAL 87, n. 6 (1 novembre 2004): 1368–79. http://dx.doi.org/10.1093/jaoac/87.6.1368.
Testo completoAbstract (sommario):
Abstract The uneven distribution of pesticide residues among the treated objects leads to an inevitable variability of pesticide residue levels measured in the samples, which may significantly contribute to the combined uncertainty of the analytical results. A total of 8844 unit-crop residue data derived from 57 lots and 19 field trials were evaluated to determine the characteristic features of residue distribution in unit crops and composite samples. The average residue levels and the corresponding coefficient of variation (CV) values obtained for individual units taken from a given lot showed wide variation from lot to lot. There was no significant difference between the CVs of residue levels in sample sets of various unit crops or composite sample populations of different sizes taken from various crops. The CV values for levels of residues taken from individual lots followed normal distribution. Very good correlation was found between the CVs of the parent and sample populations. The experimentally obtained values were very close to those expected on the basis of the central limit theorem. The estimated typical relative standard uncertainties of sampling medium-size crops for pesticide residue analysis in the cases of sample sizes of 5, 10, and 25 were 37, 25, and 16%, respectively.
2
Sue Brady, Marietta, e Stanley E. Katz. "In Vitro Effect of Multiple Antibiotic/Antimicrobial Residues on the Selection for Resistance in Bacteria". Journal of AOAC INTERNATIONAL 75, n. 4 (1 luglio 1992): 738–41. http://dx.doi.org/10.1093/jaoac/75.4.738.
Testo completoAbstract (sommario):
Abstract A method using a gram-positive and a gram-negative organism was used to investigate the selection for resistant populations after exposure to residue levels of 7 antibiotics and 1 antimicrobial. The organisms were exposed to individual compounds and combinations of 3 compounds for 14 days. The changes in minimum inhibitory concentration (MIC) of a panel of 8 antibiotics and 1 antimicrobial were used as the measure of resistance development/selection. For Staphylococcus aureus ATCC 9144, exposure to residue levels of oxytetracycline, tylosin, penicillin, and virginiamycin resulted in an increased MIC of the compound itself; most individual residues did not result in increased cross-resistance. With combinations of residues, 13 of 45 determinations resulted in significant increases in MIC. Enterobacter cloacae B520, which was much less sensitive to 4 of 9 markers, showed MIC increases only for tylosin and the combination of neomycin-sulfamethazine-oxytetracycline. The results indicate an interaction among residue levels of antibiotics in selection for resistance.
3
Sao, Prachi, Anupam Singh e Sachidanand Singh. "Predicting Rheumatoid Arthritis Associated Significant Amino-Acid Residues Using Residue-Residue Interaction Analysis". Bangladesh Journal of Medical Science 21, n. 4 (11 settembre 2022): 698–710. http://dx.doi.org/10.3329/bjms.v21i4.60281.
Testo completoAbstract (sommario):
Rheumatoid Arthritis (RA) is a prevalent autoimmune and inflammatory disease that requires restructuring. A lot of research information is available, but a clear etiology and drug target information is still unclear. A bottom-up approach can add more information to existing knowledge about RA. One better way of understanding the disease-related mechanism and drug objectives can be a detailed residue-residue interaction of the proteins involved with RA. In the current research work, we have studied the significant proteins reported in the Indian population that are involved in RA progression and have represented each of them as a complex network of amino acid residues to understand the significance of individual residues in the network. We implied the graph theory approach to identity central important residue, based on topological properties of the network. This approach allows us to look at a more precise method to identify potential drug targets. Our result identified leucine, phenylalanine, tyrosine, and tryptophan as essential nodes in the network, their activity was mainly connected with immune system. Understanding the function of these amino acids in CTLA4, CD40, IRF5, IL2RB, and TRAF could lead to a new treatment options in the fight against Rheumatoid Arthritis. Bangladesh Journal of Medical Science Vol. 21 No. 04 October’22 Page : 698-710
4
Kovář, Jan, e Ivana Matysková. "Effect of modification of certain amino acid residues on enzyme activity of D-3-hydroxybutyrate dehydrogenase from bacterium Paracoccus denitrificans". Collection of Czechoslovak Chemical Communications 52, n. 7 (1987): 1872–77. http://dx.doi.org/10.1135/cccc19871872.
Testo completoAbstract (sommario):
We examined the effect of several modifying reagents on the activity of the title enzyme. The results show that one histidine residue participates in the interaction of the enzyme with the substrate; one cysteine residue binds near to the nicotine amide moiety of the coenzyme molecule and its role is to induce conformational changes leading to the formation of enzyme aggregates with an increased catalytic power. The enzyme does not contain essential tyrosine and tryptophan residues. The results of the experiments with the modification of additional amino acid residues permit us to make preliminary conclusions only based on the knowledge of the protective effect of the individual ligands: One arginine residue may be involved in the binding of the coenzyme, the residues of lysine and serine may be localized in the substrate binding site.
5
Tsushima, Robert G., Ronald A. Li e Peter H. Backx. "P-loop Flexibility in Na+ Channel Pores Revealed by Single- and Double-cysteine Replacements". Journal of General Physiology 110, n. 1 (1 luglio 1997): 59–72. http://dx.doi.org/10.1085/jgp.110.1.59.
Testo completoAbstract (sommario):
Replacement of individual P-loop residues with cysteines in rat skeletal muscle Na+ channels (SkM1) caused an increased sensitivity to current blockade by Cd2+ thus allowing detection of residues lining the pore. Simultaneous replacement of two residues in distinct P-loops created channels with enhanced and reduced sensitivity to Cd2+ block relative to the individual single mutants, suggesting coordinated Cd2+ binding and cross-linking by the inserted sulfhydryl pairs. Double-mutant channels with reduced sensitivity to Cd2+ block showed enhanced sensitivity after the application of sulfhydryl reducing agents. These results allow identification of residue pairs capable of approaching one another to within less than 3.5 Å. We often observed that multiple consecutive adjacent residues in one P-loop could coordinately bind Cd2+ with a single residue in another P-loop. These results suggest that, on the time-scale of Cd2+ binding to mutant Na+ channels, P-loops show a high degree of flexibility.
6
Ambrus, Árpád, Júlia Szenczi-Cseh, Vy Vy N. Doan e Adrienn Vásárhelyi. "Evaluation of Monitoring Data in Foods". Agrochemicals 2, n. 1 (18 gennaio 2023): 69–95. http://dx.doi.org/10.3390/agrochemicals2010006.
Testo completoAbstract (sommario):
Pesticide residue monitoring data reflect the actual residues in foods as traded and are suitable for estimating consumers’ exposure, evaluating compliance with maximum residue limits, MRLs, and refining future risk-based sampling programmes. The long-term exposure (daily intake) is calculated from the national or regional food consumption data and average residues in the edible portions of food. The non-detected residues may be counted as LOQ, 0.5 LOQ, or 0. The short-term intake is calculated from the large portion consumption of individual foods multiplied by the highest residue concentration found in them and the relevant variability factor. Dietary exposure to a pesticide residue may be characterised by the hazard quotient (HQ) and the hazard index (HI). Cumulative exposure should only be assessed for those compounds having the common mechanism of toxicity (cumulative assessment group, CAG). The number of residue data required for these assessments should be calculated with distribution-free statistics at the targeted confidence level. The proper evaluation of the numerous results can only be completed if they are electronically recorded and can be retrieved in specific formats. Our objectives are to present methods for consumer risk assessment, testing compliance with MRLs, and ranking commodities for risk-based sampling and to give examples of electronic processing of residue data.
7
Lin, Qinhao, Guohua Zhang, Long Peng, Xinhui Bi, Xinming Wang, Fred J. Brechtel, Mei Li et al. "In situ chemical composition measurement of individual cloud residue particles at a mountain site, southern China". Atmospheric Chemistry and Physics 17, n. 13 (12 luglio 2017): 8473–88. http://dx.doi.org/10.5194/acp-17-8473-2017.
Testo completoAbstract (sommario):
Abstract. To investigate how atmospheric aerosol particles interact with chemical composition of cloud droplets, a ground-based counterflow virtual impactor (GCVI) coupled with a real-time single-particle aerosol mass spectrometer (SPAMS) was used to assess the chemical composition and mixing state of individual cloud residue particles in the Nanling Mountains (1690 m a. s. l. ), southern China, in January 2016. The cloud residues were classified into nine particle types: aged elemental carbon (EC), potassium-rich (K-rich), amine, dust, Pb, Fe, organic carbon (OC), sodium-rich (Na-rich) and Other. The largest fraction of the total cloud residues was the aged EC type (49.3 %), followed by the K-rich type (33.9 %). Abundant aged EC cloud residues that mixed internally with inorganic salts were found in air masses from northerly polluted areas. The number fraction (NF) of the K-rich cloud residues increased within southwesterly air masses from fire activities in Southeast Asia. When air masses changed from northerly polluted areas to southwesterly ocean and livestock areas, the amine particles increased from 0.2 to 15.1 % of the total cloud residues. The dust, Fe, Pb, Na-rich and OC particle types had a low contribution (0.5–4.1 %) to the total cloud residues. Higher fraction of nitrate (88–89 %) was found in the dust and Na-rich cloud residues relative to sulfate (41–42 %) and ammonium (15–23 %). Higher intensity of nitrate was found in the cloud residues relative to the ambient particles. Compared with nonactivated particles, nitrate intensity decreased in all cloud residues except for dust type. To our knowledge, this study is the first report on in situ observation of the chemical composition and mixing state of individual cloud residue particles in China.
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Journal, Baghdad Science. "Testing the ability of Porcellionides pruinosus (Brandt 1833) Isopoda Crustaceans to decompose and consume cellulosean wastes in different ecosystems". Baghdad Science Journal 9, n. 3 (2 settembre 2012): 397–405. http://dx.doi.org/10.21123/bsj.9.3.397-405.
Testo completoAbstract (sommario):
The present study was undertaken to use individual terrestrial crustacean from Isopoda such as the species Porcellionides pruinosus (Brandt 1833) as environmental cleaner and that through the test of their abilities in decomposition of residues of some cellulosean wastes such as wood pieces which contain high ratio of urban wastes, and residue of Zea mays and particularly leaves as plant waste in agricultural fields and residue of Cynodon dactylon plants which compose the main wastes in most of gardens and parks. Experiments were conducted relatively in stable laboratory conditions to ensure environmental conditions similar to crustaceans' life. The results showed presence of good efficiency of these individuals in treating such wastes as they consumed 89% of wood pieces and 59% of Zea mays leaves and 27% of residue of Cynodon dactylon plants during the period of treatment. The average of each crustacean individual to consume was 0.74, 0.49 and 0.22 gram from the material mentioned respectively. So, it is recommend to conduct further experiments on different models of agricultural and civil wastes by using different species of these organisms to carry out such studies with a broad spectrum in future to treat the wastes and pollutants of environment by biological approach.
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Berg, Erik C., Eric A. Simmons, Todd A. Morgan e Stanley J. Zarnoch. "Predicting Logging Residue Volumes in Alaska". Forest Science 67, n. 2 (11 gennaio 2021): 119–24. http://dx.doi.org/10.1093/forsci/fxaa052.
Testo completoAbstract (sommario):
Abstract Alaska forest managers seek information on how timber harvesting practices change the creation of postharvest woody residues. To predict residue volumes, researchers investigated how residue ratios—growing-stock residue volume per mill-delivered volume—related to readily available data on logging site and tree attributes in Alaska. Residue ratios were not related to logging site-level variables but were related to individual tree variables with predictive models. Ratios varied widely by tree species and were predicted to increase with larger stump height and larger small-end used diameters and decline exponentially with increasing diameter breast height (dbh) to approximately 25 inches. Ratios were then predicted to increase progressively in larger dbh trees. Results from this study update previous findings in other US Northwest states and can be used to produce or improve residue prediction tools for Alaska land managers.
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McKinney, J. S., X. T. Fu, C. Swearingen, E. Klohe e R. W. Karr. "Individual effects of the DR11-variable beta-chain residues 67, 71, and 86 upon DR(alpha,beta 1*1101)-restricted, peptide-specific T cell proliferation." Journal of Immunology 153, n. 12 (15 dicembre 1994): 5564–71. http://dx.doi.org/10.4049/jimmunol.153.12.5564.
Testo completoAbstract (sommario):
Abstract The four members of the HLA-DR11 family of class II molecules vary only by three or fewer amino acids via dimorphisms among DR beta-chain residues 67, 71, and 86. However, they differ markedly in their abilities to induce proliferation of DR(alpha,beta 1*1101)-restricted, peptide-specific T cell clones. To dissect which DR11-variable residues, individually and in combination, mediate these functional differences, we used as APC transfectants expressing DR molecules with one of all possible permutations of DR11-variable sequences, including the four DR11 family members, and four additional DR11 variant mutants. The abilities of the wild-type or mutant molecules to present two distinct influenza peptide Ags, HA307-19 and HA128-45, to T cells was assessed in in vitro T cell proliferation assays. Of the naturally dimorphic DR11 positions, residue beta 71 variation significantly influenced the ability of DR11 molecules to present both peptides to DR(alpha,beta 1*1101)-restricted T cells. Residue beta 86 variation had relatively less influence than reported in several other DR and peptide systems. Residue beta 67 variation usually appeared irrelevant to T cell proliferation, but in two mutants led to unexpected T cell proliferation independent of nominal peptide Ag. Peptide binding, assessed by flow cytometry, was not found to be altered by any mutations that disrupted DR(alpha,beta 1*1101)-like presentation. These data indicate that residue beta 71 exerts a central role in influencing the functional differences among DR11 molecules, whereas the widely studied dimorphism of residue beta 86 is not as generally influential in DR11 as in other alleles.
11
Floyd, PB, PG Gallagher, LA Valentino, M. Davis, SL Marchesi e BG Forget. "Heterogeneity of the molecular basis of hereditary pyropoikilocytosis and hereditary elliptocytosis associated with increased levels of the spectrin alpha I/74-kilodalton tryptic peptide". Blood 78, n. 5 (1 settembre 1991): 1364–72. http://dx.doi.org/10.1182/blood.v78.5.1364.1364.
Testo completoAbstract (sommario):
Abstract Hereditary pyropoikilocytosis (HPP) and hereditary elliptocytosis are closely related, congenital disorders of the red blood cell usually associated with defective spectrin self-association and abnormal limited tryptic digestion of the N-terminal of domain of spectrin. Enhanced cleavage by trypsin of spectrin from affected individuals at arginyl residue 45* and lysyl residue 48* frequently yields increased amounts of an alpha 1/74-Kd fragment at the expense of the normal alpha 1/80-Kd parent fragment. Limited tryptic digestion of three unrelated individuals with HPP showed the alpha 1/74 defect. To ascertain the molecular defect responsible for the abnormality, the structure of exon 2 of the alpha-spectrin gene was examined. Genomic DNA from the subjects was amplified by the polymerase chain reaction using primers flanking exon 2. Restriction endonuclease digestion of amplified products showed the loss of the HindIII site at codons 47 and 48 in one allele of subject 1 and abolished the AhaII site at codons 27 and 28 in one allele of subjects 2 and 3. Nucleotide sequence analysis of subcloned amplified DNA from the HPP subjects showed three novel amino acid substitutions. In subject 1 (a black individual), a single base substitution (AAG----AGG) at codon position 48 changes amino acid residue lysine to arginine. In subject 2 (a white individual), a single base substitution (CGT----AGT) at codon 28 changes arginine to serine. In subject 3 (a black individual), a different base substitution at position 28 (CGT----CTT) changes arginine to leucine. These mutations occur at positions of the alpha l domain where other mutations have also been described, indicating that the normal residues at these positions play an important role in spectrin dimer self-association and thus, in membrane stability.
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Floyd, PB, PG Gallagher, LA Valentino, M. Davis, SL Marchesi e BG Forget. "Heterogeneity of the molecular basis of hereditary pyropoikilocytosis and hereditary elliptocytosis associated with increased levels of the spectrin alpha I/74-kilodalton tryptic peptide". Blood 78, n. 5 (1 settembre 1991): 1364–72. http://dx.doi.org/10.1182/blood.v78.5.1364.bloodjournal7851364.
Testo completoAbstract (sommario):
Hereditary pyropoikilocytosis (HPP) and hereditary elliptocytosis are closely related, congenital disorders of the red blood cell usually associated with defective spectrin self-association and abnormal limited tryptic digestion of the N-terminal of domain of spectrin. Enhanced cleavage by trypsin of spectrin from affected individuals at arginyl residue 45* and lysyl residue 48* frequently yields increased amounts of an alpha 1/74-Kd fragment at the expense of the normal alpha 1/80-Kd parent fragment. Limited tryptic digestion of three unrelated individuals with HPP showed the alpha 1/74 defect. To ascertain the molecular defect responsible for the abnormality, the structure of exon 2 of the alpha-spectrin gene was examined. Genomic DNA from the subjects was amplified by the polymerase chain reaction using primers flanking exon 2. Restriction endonuclease digestion of amplified products showed the loss of the HindIII site at codons 47 and 48 in one allele of subject 1 and abolished the AhaII site at codons 27 and 28 in one allele of subjects 2 and 3. Nucleotide sequence analysis of subcloned amplified DNA from the HPP subjects showed three novel amino acid substitutions. In subject 1 (a black individual), a single base substitution (AAG----AGG) at codon position 48 changes amino acid residue lysine to arginine. In subject 2 (a white individual), a single base substitution (CGT----AGT) at codon 28 changes arginine to serine. In subject 3 (a black individual), a different base substitution at position 28 (CGT----CTT) changes arginine to leucine. These mutations occur at positions of the alpha l domain where other mutations have also been described, indicating that the normal residues at these positions play an important role in spectrin dimer self-association and thus, in membrane stability.
13
Ahola, Virpi, Tero Aittokallio, Esa Uusipaikka e Mauno Vihinen. "Statistical Methods for Identifying Conserved Residues in Multiple Sequence Alignment". Statistical Applications in Genetics and Molecular Biology 3, n. 1 (30 gennaio 2004): 1–28. http://dx.doi.org/10.2202/1544-6115.1074.
Testo completoAbstract (sommario):
The assessment of residue conservation in a multiple sequence alignment is a central issue in bioinformatics. Conserved residues and regions are used to determine structural and functional motifs or evolutionary relationships between the sequences of a multiple sequence alignment. For this reason, residue conservation is a valuable measure for database and motif search or for estimating the quality of alignments. In this paper, we present statistical methods for identifying conserved residues in multiple sequence alignments. While most earlier studies examine the positional conservation of the alignment, we focus on the detection of individual conserved residues at a position. The major advantages of multiple comparison methods originate from their ability to select conserved residues simultaneously and to consider the variability of the residue estimates. Large-scale simulations were used for the comparative analysis of the methods. Practical performance was studied by comparing the structurally and functionally important residues of Src homology 2 (SH2) domains to the assignments of the conservation indices. The applicability of the indices was also compared in three additional protein families comprising different degrees of entropy and variability in alignment positions. The results indicate that statistical multiple comparison methods are sensitive and reliable in identifying conserved residues.
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Yadav, Mohini, Manabu Igarashi e Norifumi Yamamoto. "Dynamic residue interaction network analysis of the oseltamivir binding site of N1 neuraminidase and its H274Y mutation site conferring drug resistance in influenza A virus". PeerJ 9 (2 giugno 2021): e11552. http://dx.doi.org/10.7717/peerj.11552.
Testo completoAbstract (sommario):
Background Oseltamivir (OTV)-resistant influenza virus exhibits His-to-Tyr mutation at residue 274 (H274Y) in N1 neuraminidase (NA). However, the molecular mechanisms by which the H274Y mutation in NA reduces its binding affinity to OTV have not been fully elucidated. Methods In this study, we used dynamic residue interaction network (dRIN) analysis based on molecular dynamics simulation to investigate the correlation between the OTV binding site of NA and its H274Y mutation site. Results dRIN analysis revealed that the OTV binding site and H274Y mutation site of NA interact via the three interface residues connecting them. H274Y mutation significantly enhanced the interaction between residue 274 and the three interface residues in NA, thereby significantly decreasing the interaction between OTV and its surrounding loop 150 residues. Thus, we concluded that such changes in residue interactions could reduce the binding affinity of OTV to NA, resulting in drug resistant influenza viruses. Using dRIN analysis, we succeeded in understanding the characteristic changes in residue interactions due to H274Y mutation, which can elucidate the molecular mechanism of reduction in OTV binding affinity to influenza NA. Finally, the dRIN analysis used in this study can be widely applied to various systems such as individual proteins, protein-ligand complexes, and protein-protein complexes, to characterize the dynamic aspects of the interactions.
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Deckhut, A. M., e S. S. Tevethia. "Effect of point mutations in the native simian virus 40 tumor antigen, and in synthetic peptides corresponding to the H-2Db-restricted epitopes, on antigen presentation and recognition by cytotoxic T lymphocyte clones." Journal of Immunology 148, n. 10 (15 maggio 1992): 3012–20. http://dx.doi.org/10.4049/jimmunol.148.10.3012.
Testo completoAbstract (sommario):
Abstract The effects on CTL recognition of individual amino acid substitutions within epitopes I, II, and III of SV40 tumor Ag (T Ag) were examined. Epitope I spans amino acids 207 to 215, and epitope II/III is within residues 223 to 231 of SV40 T Ag. An amino acid substitution at position 207 (Ala----Val) or 214 (Lys----Glu) of SV40 T Ag expressed in transformed cells resulted in loss of epitope I, recognized by CTL clone Y-1. The amino acid substitution at residue 214 in the corresponding synthetic peptide, LT207-215(214-Lys----Glu), also led to loss of recognition by CTL clone Y-1. The recognition, by CTL clone Y-1, of peptides LT207-215 and LT207-217 with an Ala----Val substitution at position 207 was severely affected. Peptides LT205-215 and LT205-219 with the Ala----Val substitution at residue 207 were, however, recognized by CTL clone Y-1, suggesting that residues 205 and 206 may be involved in presentation of site I. Alteration of residue 224 (Lys----Glu) in the native T Ag resulted in loss of recognition by both CTL clones Y-2 and Y-3. However, a peptide corresponding to epitope II/III with an identical amino acid substitution at residue 224 provided a target for CTL clone Y-3 but not clone Y-2. A change of Lys----Gln at residue 224 in both the native protein and a synthetic peptide caused loss of recognition by CTL clone Y-2 but not CTL clone Y-3. Further, an amino acid substitution of Lys----Arg at position 224 of the native T Ag decreased recognition of epitope II/III by CTL clones Y-2 and Y-3 but had no effect on recognition of a synthetic peptide bearing the same substitution. These results indicate that the mutagenesis approach, resulting in identical amino acid substitutions in the native protein and in the synthetic peptides, may provide insight into the role of individual residues in the processing, presentation, and recognition of CTL recognition epitopes.
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Shi, Andong, e Petra Marschner. "Changes in microbial biomass C, extractable C and available N during the early stages of decomposition of residue mixtures". Soil Research 52, n. 4 (2014): 366. http://dx.doi.org/10.1071/sr13128.
Testo completoAbstract (sommario):
Decomposition of mixed residues is common in many ecosystems, with residues from different species or above- and below-ground residues from the same species. Although decomposition of litter mixtures has been extensively studied, little is known about the changes in microbial biomass carbon (C) and available nitrogen (N) in the early stages of decomposition of mixtures of shoots and roots. An incubation experiment was carried out in a sandy clay loam with shoot and root residues of two grasses, annual barley (Hordeum vulgare L.), and perennial Stipa sp., added separately or as mixtures. Soil respiration was measured continuously, and soil microbial biomass C, extractable C and available N were measured by destructive sampling on days 0, 3, 6, 9, 12 and 18. Cumulative respiration and microbial biomass C concentration were higher with barley shoots alone or in mixtures than with Stipa residues alone. In the mixture of Stipa shoots and roots, which had similar decomposition rates when incubated individually, the measured cumulative respiration was greater than the expected value (average of the cumulative respiration of the individual residues), but this did not result in greater microbial biomass or changes in available N concentration compared with the individual residues. Cumulative respiration of barley shoots alone was higher than of barley root and Stipa shoot incubated individually. In the mixtures of barley shoots with barley roots or Stipa shoots, the measured cumulative respiration was either lower than the expected value or similar. Compared with barley shoots alone, microbial biomass C concentrations in the mixtures were generally lower in the first 3 days. It is concluded that mixing of residues with similar decomposition rates can stimulate microbial activity (respiration) but has little effect on microbial growth or concentrations of available N. Further, our findings provide information about extractable C and N dynamics during the early stages of decomposition of individual residue and residue mixtures.
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Doshi, Urmi, Michael J. Holliday, Elan Z. Eisenmesser e Donald Hamelberg. "Dynamical network of residue–residue contacts reveals coupled allosteric effects in recognition, catalysis, and mutation". Proceedings of the National Academy of Sciences 113, n. 17 (11 aprile 2016): 4735–40. http://dx.doi.org/10.1073/pnas.1523573113.
Testo completoAbstract (sommario):
Detailed understanding of how conformational dynamics orchestrates function in allosteric regulation of recognition and catalysis remains ambiguous. Here, we simulate CypA using multiple-microsecond-long atomistic molecular dynamics in explicit solvent and carry out NMR experiments. We analyze a large amount of time-dependent multidimensional data with a coarse-grained approach and map key dynamical features within individual macrostates by defining dynamics in terms of residue–residue contacts. The effects of substrate binding are observed to be largely sensed at a location over 15 Å from the active site, implying its importance in allostery. Using NMR experiments, we confirm that a dynamic cluster of residues in this distal region is directly coupled to the active site. Furthermore, the dynamical network of interresidue contacts is found to be coupled and temporally dispersed, ranging over 4 to 5 orders of magnitude. Finally, using network centrality measures we demonstrate the changes in the communication network, connectivity, and influence of CypA residues upon substrate binding, mutation, and during catalysis. We identify key residues that potentially act as a bottleneck in the communication flow through the distinct regions in CypA and, therefore, as targets for future mutational studies. Mapping these dynamical features and the coupling of dynamics to function has crucial ramifications in understanding allosteric regulation in enzymes and proteins, in general.
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De Becdelievre, Pauline, e François Grima. "How does emotion residue affect an individual after switching organizations?" Academy of Management Proceedings 2017, n. 1 (agosto 2017): 15736. http://dx.doi.org/10.5465/ambpp.2017.15736abstract.
Testo completo
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Maddelein, Marie-Lise, e Reed B. Wickner. "Two Prion-Inducing Regions of Ure2p Are Nonoverlapping". Molecular and Cellular Biology 19, n. 6 (1 giugno 1999): 4516–24. http://dx.doi.org/10.1128/mcb.19.6.4516.
Testo completoAbstract (sommario):
ABSTRACT Ure2p of Saccharomyces cerevisiae normally functions in blocking utilization of a poor nitrogen source when a good nitrogen source is available. The non-Mendelian genetic element [URE3] is a prion (infectious protein) form of Ure2p, so that overexpression of Ure2p induces the de novo appearance of infectious [URE3]. Earlier studies defined a prion domain comprising Ure2p residues 1 to 64 and a nitrogen regulation domain included in residues 66 to 354. We find that deletion of individual runs of asparagine within the prion domain reduce prion-inducing activity. Although residues 1 to 64 are sufficient for prion induction, the fragment from residues 1 to 80 is a more efficient inducer of [URE3]. In-frame deletion of a region around residue 224 does not affect nitrogen regulation but does eliminate prion induction by the remainder of Ure2p. Larger deletions removing the region around residue 224 and more of the C-terminal part of Ure2p restore prion-inducing ability. A fragment of Ure2p lacking the original prion domain does not induce [URE3], but surprisingly, further deletion of residues 151 to 157 and 348 to 354 leaves a fragment that can do so. The region from 66 to 80 and the region around residue 224 are both necessary for this second prion-inducing activity. Thus, each of two nonoverlapping parts of Ure2p is sufficient to induce the appearance of the [URE3] prion.
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REYES-HERRERA, IXCHEL, e DAN J. DONOGHUE. "Antibiotic Residues Distribute Uniformly in Broiler Chicken Breast Muscle Tissue". Journal of Food Protection 71, n. 1 (1 gennaio 2008): 223–25. http://dx.doi.org/10.4315/0362-028x-71.1.223.
Testo completoAbstract (sommario):
Use of antibiotics by the poultry industry has the potential to produce residues in edible tissues. In order to protect consumers, the U.S. federal government performs extensive evaluations to quantify residues in edible tissues to ensure that concentrations do not exceed the tolerance level. However, in the case of muscle tissue, the regulatory process does not differentiate between different edible muscle types in poultry. Previous studies performed by our laboratory determined higher fluoroquinolone residue concentrations in breast versus thigh muscle. Thus, if thigh tissues were used for residue monitoring, it would not accurately depict the higher concentrations. It is also possible that residue concentrations vary within tissues. To evaluate this possibility, fluoroquinolone antibiotic residues were determined for different breast sections. One hundred sixty chickens were randomly divided into four groups and dosed at 33 days of age with the fluoroquinolone antibiotic, enrofloxacin (Baytril), at either 25 ppm for 3 days, 25 ppm for 7 days, 50 ppm for 3 days, or 50 ppm for 7 days. Breast fillets were collected from each bird (n = 5 birds per day per group) during the dosing and withdrawal period. Each breast was divided into four sections (upper left, upper right, lower left, and lower right) that were analyzed as individual samples for determination of fluoroquinolone concentration. Our results indicated no significant difference (P > 0.05) in the levels of enrofloxacin residues between breast sections during the dosing or withdrawal periods. Consequently, samples can be collected from any breast section to evaluate fluoroquinolone residue concentrations during the regulatory monitoring process.
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Fredrikson, Levi, Patricia A. Skinkis e Ed Peachey. "Cover Crop and Floor Management Affect Weed Coverage and Density in an Establishing Oregon Vineyard". HortTechnology 21, n. 2 (aprile 2011): 208–16. http://dx.doi.org/10.21273/horttech.21.2.208.
Testo completoAbstract (sommario):
Five vineyard floor management treatments were evaluated for effects on weed control over two growing seasons in an establishing ‘Chardonnay’ (Vitis vinifera) vineyard in the Willamette Valley of Oregon. Four cover crop management treatments and an unplanted treatment were compared to assess the effects on vine row and alleyway weed coverage and densities of broadleaf and grass weeds. A winter annual cover crop was grown in alleyways of the cover-cropped treatments and was mowed in spring. The mowed residue was managed as follows: 1) residue transferred in-row as mulch representing the industry practice of “mow-and-throw,” 2) residue transferred in-row as mulch at three times the rate of the earlier treatment, 3) mowed residue incorporated into alleyways, and 4) removal of mowed cover crop residue from the vineyard. Weed coverage was assessed visually within a 1.0-m2 quadrat placed randomly in alleyways and vine rows, and densities of broadleaf and grass weeds were determined by counting and grouping individual weeds within each quadrat. Vine row weed coverage and densities were lower in treatments with residue mulch at each sampling date in 2009 and 2010, with nearly 100% in-row weed suppression by the heavier mulch treatment. Alleyway weed coverage was lowest when residue was incorporated and highest in the unplanted treatment at some sampling dates. Grass weed densities in alleyways were similar between treatments at all sampling dates. Results of this study indicate that in-row mulch of cover crop residues at fresh weight densities of 2.5–15.0 kg·m−2 provided effective weed control in a non-irrigated vineyard in western Oregon. Also, alleyway weed coverage may be reduced through incorporation of mowed cover crop residues.
22
Li, Wenjing, Huiquan Bi, Duncan Watt, Yun Li, Mohammad Reza Ghaffariyan e Fabiano Ximenes. "Estimation and Spatial Mapping of Residue Biomass following CTL Harvesting in Pinus radiata Plantations: An Application of Harvester Data Analytics". Forests 13, n. 3 (9 marzo 2022): 428. http://dx.doi.org/10.3390/f13030428.
Testo completoAbstract (sommario):
The utilization of forest harvest residues for renewable bioenergy production and bioproducts has increasingly become an integrated part of forestry that helps to meet the needs of climate change mitigation and a future carbon neutral economy. An essential element in the planning of any harvesting residue recovery operation is a reliable assessment of the quantity and quality of residue biomass and its composition over a harvest area. With the now widely adopted cut-to-length (CTL) at the stump harvesting system in Pinus radiata plantations in Australia, harvesting residues left on site are significantly larger in quantity and spatially more dispersed over a harvest area in comparison to the more traditional whole-tree harvesting. The conventional approach of assessing forest harvest residues through sample plots, transects, or small study blocks has provided site-specific estimates of residue biomass. However, these estimates cannot be readily extrapolated over the plantation landscape, which varies in silviculture, site, and stand conditions. To overcome this limitation, this study relied on harvester data analytics to obtain spatially explicit estimates of residue biomass using an example data set from harvested plantations of three stand types: unthinned (T0), thinned once (T1), and thinned twice (T2). Three methods of integrating biomass equations with harvester data were compared for residue biomass estimation: (1) applying individual tree biomass equations to harvested stems, (2) applying stand-level biomass equations to gridded harvester data, and (3) integrating estimates from the first approach with recorded and estimated waste volumes of harvested stems. The estimates of total residue biomass obtained using the three methods through harvester data analytics varied between 56.2 and 156.4 t/ha in green weight across the three stand types. These estimates were validated indirectly through ex situ sample plots and proved to be comparable to the quantities of residue biomass assessed using conventional sample plots, transects, or small blocks following CTL harvesting of rotation age P. radiata plantations elsewhere in Australia. Among the three methods, the third method made the most intensive use of the harvester data and provided the most realistic estimates of residue biomass. Spatial mapping of the estimated total and component residue biomass will assist the operational planning of residue recovery and site-specific nutrient management for the long-term sustainability of P. radiata plantations.
23
Hunt, H. D., J. K. Pullen, R. F. Dick, J. A. Bluestone e L. R. Pease. "Structural basis of Kbm8 alloreactivity. Amino acid substitutions on the beta-pleated floor of the antigen recognition site." Journal of Immunology 145, n. 5 (1 settembre 1990): 1456–62. http://dx.doi.org/10.4049/jimmunol.145.5.1456.
Testo completoAbstract (sommario):
Abstract We have analyzed the functional significance of the four amino acid differences between the parental H-2Kb and mutant H-2Kbm8 glycoproteins. Six bm8 variants including single substitutions at residues 22, 23, 24, and 30 as well as paired substitutions at residues 23, 30 and 22, 24 were generated and transfected into L cells. Surface expression of these H-2Kb variants was analyzed using monoclonal antibodies which bind to well-defined H-2Kb epitopes. No alterations introduced into the conformational structure of H-2Kb by the amino acid substitutions were detected. The effect of these substitutions on CTL recognition was initially analyzed using the following bulk CTL: either H-2Kb anti-H-2Kbm8, H-2Kbm8 anti-H-2Kb, or third party anti-H-2Kb. The alloreactivity between H-2Kb and H-2Kbm8 is dominated by the amino acid substitution at residue 24 (Glu----Ser). The complete bm8 phenotype, however, also requires the additional substitution at residue 22 (Tyr----Phe). The H-2Kbm8 anti-Kb bulk CTL reacted with both variant H-2Kbm8 molecules containing single substitutions at amino acid positions 22 or 24 but not the variant molecule containing both substitutions. Further analysis using three individual H-2Kbm8 anti-Kb CTL clones indicated the complexity of the self Kbm8 phenotype. Clone 8B1.20 did not react to changes in residues 22 or 24. The 8B1.32 clone reacted with the change at residue 22 but not with the change at residue 24, although the 8B1.54 clone reacted with the change at residue 24 but not with the change at residue 22. The changes in residues 23 (Met----Ile) and/or 30 (Asp----Asn) did not impact significantly on the alloantigenic properties of Kbm8 as determined by both the bulk and cloned CTL populations. According to the three-dimensional class I structure the substitution at amino acid 24 is inaccessible to the TCR. The location of this substitution within the Ag recognition site implies that altered peptide binding, and not a disruption of MHC residues that interact with the TCR, is responsible for the alloreactivity between H-2Kb and H-2Kbm8.
24
Chen, Jun, Fan Deng, Jun Li e Q. Jane Wang. "Selective binding of phorbol esters and diacylglycerol by individual C1 domains of the PKD family". Biochemical Journal 411, n. 2 (27 marzo 2008): 333–42. http://dx.doi.org/10.1042/bj20071334.
Testo completoAbstract (sommario):
The PKD (protein kinase D) family are novel DAG (diacylglycerol) receptors. The twin C1 domains of PKD, designated C1a and C1b, have been shown to bind DAG or phorbol esters. However, their ligand-binding activities and selectivities have not been fully characterized. Here, binding activities of isolated C1a, C1b and intact C1a–C1b domains to DAG and phorbol esters were analysed. The isolated C1b domains of PKD isoforms bind [3H]PDBu ([20-3H]phorbol 12, 13-dibutyrate) with similar high affinities, while they exhibit weaker affinities towards a synthetic DAG analogue, DOG (1,2-dioctanoyl-sn-glycerol), as compared to the control. Mutating a conserved lysine residue at position 22 to tryptophan in C1b of PKD3 fully restores its affinity to DOG, indicating that this residue accounts for its weaker affinity to DOG. In contrast, the non-consensus residues in the isolated C1a domain of PKD mainly contribute to maintaining the protein's structural fold, since converting these residues in C1a of PKD3 to those in PKD1 or PKD2 drastically reduces the maximal number of active receptors, while only minimally impacting ligand-binding activities. Moreover, ligand-binding activities of C1a and C1b are sensitive to the structural context in an intact C1a–C1b domain and exhibit unique patterns of ligand selectivity. C1a and C1b in the intact C1a–C1b of PKD1 are opposite in selectivity for PDBu and DOG. In contrast, C1a of PKD3 exhibits 48-fold higher affinity to DOG as compared to C1b, although both domains bind PDBu with equivalent affinities. Accordingly, mutating C1a of a full-length PKD3–GFP greatly reduces DOG-induced plasma membrane translocation, but does not affect that induced by PMA. In summary, individual C1 domains of PKD isoforms differ in ligand-binding activity and selectivity, implying isoform-selective regulation of PKD by phorbol esters and DAG.
25
Theander, Olof, Per Åman, Eric Westerlund, Roger Andersson e Dan Pettersson. "Total Dietary Fiber Determined as Neutral Sugar Residues, Uronic Acid Residues, and Klason Lignin (The Uppsala Method): Collaborative Study". Journal of AOAC INTERNATIONAL 78, n. 4 (1 luglio 1995): 1030–44. http://dx.doi.org/10.1093/jaoac/78.4.1030.
Testo completoAbstract (sommario):
Abstract A joint AOAC/American Association of Cereal Chemists (AACC) collaborative study was conducted to determine by the Uppsala method the dietary fiber content and its composition in various foods. The method includes preparation of a residue by treatment with thermostable α-amylase and amyloglucosidase and then ethanol precipitation of solubilized dietary fiber components while leaving low-molecular weight carbohydrates in solution. After acid hydrolysis of residue, neutral polysaccharide residues are determined as alditol acetates by gas-liquid chromatography, uronic acid residues are determined by colorimetry, and ash-free acid-insoluble residue (Klason lignin) is determined gravimetrically. Total dietary fiber, including enzyme-resistant starch, is calculated as the sum of nonstarch polysaccharide residues and Klason lignin. Nine laboratories completed the study, analyzing in duplicate 8 unknown dried products that included 4 cereal products, green peas, potato fiber, carrots, and apples. Total dietary fiber contents of products tested ranged from 4.6 to 84.3%, with an average RSDR value of 8.4% (range, 4.8–11.1%). Total neutral polysaccharide residues ranged from 3.8 to 64.1%, with an average RSDR value of 7.5% (range, 5.4–10.5%). Individual neutral sugars (rhamnose, arabinose, xylose, mannose, galactose, and glucose) and uronic acid residues present at more than 1% generally had good RSDR values (3.3– 22.8%), whereas, as expected for Klason lignin, only the wheat bran sample with a high content (16%) had an excellent RSDR value (5.0%). The gas chromatographic-colorimetric-gravimetric method (Uppsala method) for determination of total dietary fiber (as neutral sugar residues, uronic acid residues, and Klason lignin) has been adopted first action by AOAC INTERNATIONAL.
26
Reza, Md Selim, Huiling Zhang, Md Tofazzal Hossain, Langxi Jin, Shengzhong Feng e Yanjie Wei. "COMTOP: Protein Residue–Residue Contact Prediction through Mixed Integer Linear Optimization". Membranes 11, n. 7 (30 giugno 2021): 503. http://dx.doi.org/10.3390/membranes11070503.
Testo completoAbstract (sommario):
Protein contact prediction helps reconstruct the tertiary structure that greatly determines a protein’s function; therefore, contact prediction from the sequence is an important problem. Recently there has been exciting progress on this problem, but many of the existing methods are still low quality of prediction accuracy. In this paper, we present a new mixed integer linear programming (MILP)-based consensus method: a Consensus scheme based On a Mixed integer linear opTimization method for prOtein contact Prediction (COMTOP). The MILP-based consensus method combines the strengths of seven selected protein contact prediction methods, including CCMpred, EVfold, DeepCov, NNcon, PconsC4, plmDCA, and PSICOV, by optimizing the number of correctly predicted contacts and achieving a better prediction accuracy. The proposed hybrid protein residue–residue contact prediction scheme was tested in four independent test sets. For 239 highly non-redundant proteins, the method showed a prediction accuracy of 59.68%, 70.79%, 78.86%, 89.04%, 94.51%, and 97.35% for top-5L, top-3L, top-2L, top-L, top-L/2, and top-L/5 contacts, respectively. When tested on the CASP13 and CASP14 test sets, the proposed method obtained accuracies of 75.91% and 77.49% for top-L/5 predictions, respectively. COMTOP was further tested on 57 non-redundant α-helical transmembrane proteins and achieved prediction accuracies of 64.34% and 73.91% for top-L/2 and top-L/5 predictions, respectively. For all test datasets, the improvement of COMTOP in accuracy over the seven individual methods increased with the increasing number of predicted contacts. For example, COMTOP performed much better for large number of contact predictions (such as top-5L and top-3L) than for small number of contact predictions such as top-L/2 and top-L/5. The results and analysis demonstrate that COMTOP can significantly improve the performance of the individual methods; therefore, COMTOP is more robust against different types of test sets. COMTOP also showed better/comparable predictions when compared with the state-of-the-art predictors.
27
Chaves, Otavio Augusto, e Leonardo Vazquez. "Molecular docking analysis on the interaction between bovine serum albumin and three commercial fluoroquinolones: Ciprofloxacin, enrofloxacin and pefloxacin". European Journal of Chemistry 12, n. 2 (30 giugno 2021): 192–96. http://dx.doi.org/10.5155/eurjchem.12.2.192-196.2103.
Testo completoAbstract (sommario):
Fluoroquinolones are a family of broad spectrum, systemic antibacterial agents that have been used as therapy for infections in the respiratory and alimentary tract in animals. The pharmacodynamic of this class is widely described, predominantly to the commercial drugs ciprofloxacin (CIP), enrofloxacin (ENR), and pefloxacin (PEF). Bovine serum albumin (BSA) is the main endogenous carrier in the bovine bloodstream, being responsible for the biodistribution of different classes of molecules and drugs, including fluoroquinolones. The molecular features and interaction between BSA and fluoroquinolones are not fully described, thus, the present work enlightens the intimacy of the interaction of BSA with CIP, ENR, PEF through structural modeling and molecular docking calculation approaches. The role of key amino acid residues was assessed, indicating that the main protein binding pocket is composed by Trp-212 residue playing an important stabilization for the three fluoroquinolones through both hydrogen bonding and van der Waals forces, where reside the individual structural differences observed among the three fluoroquinolones and BSA. There is a descriptive protagonism of carboxyl group on the ENR interaction which traps the molecule and avoids the deep communication in the protein binding pocket, as well as the ligands CIP and PEF showed an interface amino acid residue interaction profile higher than 70%.
28
Duenas-Decamp, Maria José, Paul J. Peters, Dennis Burton e Paul R. Clapham. "Determinants Flanking the CD4 Binding Loop Modulate Macrophage Tropism of Human Immunodeficiency Virus Type 1 R5 Envelopes". Journal of Virology 83, n. 6 (7 gennaio 2009): 2575–83. http://dx.doi.org/10.1128/jvi.02133-08.
Testo completoAbstract (sommario):
ABSTRACT Human immunodeficiency virus type 1 R5 viruses vary extensively in phenotype. Thus, R5 envelopes (env) in the brain tissue of individuals with neurological complications are frequently highly macrophage-tropic. Macrophage tropism correlates with the capacity of the envelope to exploit low CD4 levels for infection. In addition, the presence of an asparagine at residue 283 within the CD4 binding site has been associated with brain-derived envelopes, increased env-CD4 affinity, and enhanced macrophage tropism. Here, we identify additional envelope determinants of R5 macrophage tropism. We compared highly macrophage-tropic (B33) and non-macrophage-tropic (LN40) envelopes from brain and lymph node specimens of one individual. We first examined the role of residue 283 in macrophage tropism. Introduction of N283 into LN40 (T283N) conferred efficient macrophage infectivity. In contrast, substitution of N283 for the more conserved threonine in B33 had little effect on macrophage infection. Thus, B33 carried determinants for macrophage tropism that were independent of N283. We prepared chimeric B33/LN40 envelopes and used site-directed mutagenesis to identify additional determinants. The determinants of macrophage tropism that were identified included residues on the CD4 binding loop flanks that were proximal to CD4 contact residues and residues in the V3 loop. The same residues affected sensitivity to CD4-immunoglobulin G inhibition, consistent with an altered env-CD4 affinity. We predict that these determinants alter exposure of CD4 contact residues. Moreover, the CD4 binding loop flanks are variable and may contribute to a general mechanism for protecting proximal CD4 contact residues from neutralizing antibodies. Our results have relevance for env-based vaccines that will need to expose critical CD4 contact residues to the immune system.
29
Trenbath, B. R., e A. J. Diggle. "An interpretative model of carbon and nitrogentransformations applied to a residue incubation experiment". Australian Journal of Agricultural Research 49, n. 3 (1998): 537. http://dx.doi.org/10.1071/a97094.
Testo completoAbstract (sommario):
A simple model of 3 equations was devised to simulate the rates through time of gross mineralisation of nitrogen, nitrogen immobilisation, and microbial respiration relating to individual inputs into soil of plant residues of any age or type. Using published data from an incubation experiment carried out in Iowa, we applied the model to a residue newly added to soil, to the original soil organic matter (SOM), and to a mixture of these. Manipulation of the model allowed the derivation from the Iowa data of a net mineralisation index which seemed to summarise the nitrogen release characteristics of the residue in all treatments of the experiment. The equations and parameter values developed for the added residue were applied to SOM using results from unamended soil. The balance between respiration and mineralisation was found not to correspond to that expected for old organic matter near an equilibrium carbon/nitrogen ratio. Rate constants of mineralisation and respiration for SOM were adapted to overcome this apparent anomaly. To model the dynamics SOM and added residue simultaneously, the 2 sets of 3 equations were applied in parallel to 4 extreme treatments in the with-residue series (lowest and highest nitrate levels with low and high residue additions). To achieve the fits presented, only 2 of the 12 parameters required in each set of equations needed to differ between the set for SOM and that for added residue. The model reproduces well most of the primary Iowa data and also some derived results. Use of the model helped to interpret divergences between simulations and data.
30
Tedford, H. William, Alexandra E. Kisilevsky, Jean B. Peloquin e Gerald W. Zamponi. "Scanning Mutagenesis Reveals a Role for Serine 189 of the Heterotrimeric G-Protein Beta 1 Subunit in the Inhibition of N-Type Calcium Channels". Journal of Neurophysiology 96, n. 1 (luglio 2006): 465–70. http://dx.doi.org/10.1152/jn.00216.2006.
Testo completoAbstract (sommario):
Direct interactions between the presynaptic N-type calcium channel and the β subunit of the heterotrimeric G-protein complex cause voltage-dependent inhibition of N-type channel activity, crucially influencing neurotransmitter release and contributing to analgesia caused by opioid drugs. Previous work using chimeras of the G-protein β subtypes Gβ1 and Gβ5 identified two 20–amino acid stretches of structurally contiguous residues on the Gβ1 subunit as critical for inhibition of the N-type channel. To identify key modulation determinants within these two structural regions, we performed scanning mutagenesis in which individual residues of the Gβ1 subunit were replaced by corresponding Gβ5 residues. Our results show that Gβ1 residue Ser189 is critical for N-type calcium channel modulation, whereas none of the other Gβ1 mutations caused statistically significant effects on the ability of Gβ1 to inhibit N-type channels. Structural modeling shows residue 189 is surface exposed, consistent with the idea that it may form a direct contact with the N-type calcium channel α1 subunit during binding interactions.
31
Purdue, P. E., Y. Takada e C. J. Danpure. "Identification of mutations associated with peroxisome-to-mitochondrion mistargeting of alanine/glyoxylate aminotransferase in primary hyperoxaluria type 1." Journal of Cell Biology 111, n. 6 (1 dicembre 1990): 2341–51. http://dx.doi.org/10.1083/jcb.111.6.2341.
Testo completoAbstract (sommario):
We have previously shown that in some patients with primary hyperoxaluria type 1 (PH1), disease is associated with mistargeting of the normally peroxisomal enzyme alanine/glyoxylate aminotransferase (AGT) to mitochondria (Danpure, C.J., P.J. Cooper, P.J. Wise, and P.R. Jennings. J. Cell Biol. 108:1345-1352). We have synthesized, amplified, cloned, and sequenced AGT cDNA from a PH1 patient with mitochondrial AGT (mAGT). This identified three point mutations that cause amino acid substitutions in the predicted AGT protein sequence. Using PCR and allele-specific oligonucleotide hybridization, a range of PH1 patients and controls were screened for these mutations. This revealed that all eight PH1 patients with mAGT carried at least one allele with the same three mutations. Two were homozygous for this allele and six were heterozygous. In at least three of the heterozygotes, it appeared that only the mutant allele was expressed. All three mutations were absent from PH1 patients lacking mAGT. One mutation encoding a Gly----Arg substitution at residue 170 was not found in any of the control individuals. However, the other two mutations, encoding Pro----Leu and Ile----Met substitutions at residues 11 and 340, respectively, cosegregated in the normal population at an allelic frequency of 5-10%. In an individual homozygous for this allele (substitutions at residues 11 and 340) only a small proportion of AGT appeared to be rerouted to mitochondria. It is suggested that the substitution at residue 11 generates an amphiphilic alpha-helix with characteristics similar to recognized mitochondrial targeting sequences, the full functional expression of which is dependent upon coexpression of the substitution at residue 170, which may induce defective peroxisomal import.
32
Ward, Philip N., Antony J. Miles, Ian G. Sumner, Lewis H. Thomas e Alistair J. Lax. "Activity of the Mitogenic Pasteurella multocida Toxin Requires an Essential C-Terminal Residue". Infection and Immunity 66, n. 12 (1 dicembre 1998): 5636–42. http://dx.doi.org/10.1128/iai.66.12.5636-5642.1998.
Testo completoAbstract (sommario):
ABSTRACT Pasteurella multocida toxin (PMT) is a potent mitogen that also affects bone resorption. PMT acts intracellularly and is therefore postulated to have several domains involved in different aspects of its function. The toxin contains eight cysteine residues. Mutants with individual substitutions for each of these residues were constructed, and the effects of these on the biological activity of the toxin were determined by cultured-cell assays. Only the most C-terminal of the eight cysteines (C1165) was essential for full activity, although mutation of the cysteine residue at position 1159 caused a slight but reproducible loss of potency. In animal challenge experiments, mutant toxin (C1165S) was not toxic to piglets, even at doses exceeding a lethal dose of active PMT 1,000-fold. The mutant and wild-type toxins displayed identical purification characteristics, similar susceptibility to proteolytic digestion, and circular dichroism profiles, which indicated that no gross structural changes had taken place. The function of the essential C1165 residue is not yet known, although its most likely role is an enzymatic one at or near the catalytic center of the toxin.
33
Gonzalez, Carlos, Santiago Rebolledo, Marta E. Perez e H. Peter Larsson. "Molecular mechanism of voltage sensing in voltage-gated proton channels". Journal of General Physiology 141, n. 3 (11 febbraio 2013): 275–85. http://dx.doi.org/10.1085/jgp.201210857.
Testo completoAbstract (sommario):
Voltage-gated proton (Hv) channels play an essential role in phagocytic cells by generating a hyperpolarizing proton current that electrically compensates for the depolarizing current generated by the NADPH oxidase during the respiratory burst, thereby ensuring a sustained production of reactive oxygen species by the NADPH oxidase in phagocytes to neutralize engulfed bacteria. Despite the importance of the voltage-dependent Hv current, it is at present unclear which residues in Hv channels are responsible for the voltage activation. Here we show that individual neutralizations of three charged residues in the fourth transmembrane domain, S4, all reduce the voltage dependence of activation. In addition, we show that the middle S4 charged residue moves from a position accessible from the cytosolic solution to a position accessible from the extracellular solution, suggesting that this residue moves across most of the membrane electric field during voltage activation of Hv channels. Our results show for the first time that the charge movement of these three S4 charges accounts for almost all of the measured gating charge in Hv channels.
34
Alam, Md Tanvir, Jang-Soo Lee, Sang-Yeop Lee, Dhruba Bhatta, Kunio Yoshikawa e Yong-Chil Seo. "Low Chlorine Fuel Pellets Production from the Mixture of Hydrothermally Treated Hospital Solid Waste, Pyrolytic Plastic Waste Residue and Biomass". Energies 12, n. 22 (19 novembre 2019): 4390. http://dx.doi.org/10.3390/en12224390.
Testo completoAbstract (sommario):
Thirteen types of fuel pellets were prepared from hydrothermally treated hospital solid waste, hydrothermally treated rice straw, pyrolytic plastic waste residue, rice straw, and Sakhalin fir residue using a flat die pellet machine. Different pellet properties such as pellet density, pellet durability, aspect ratio, physicochemical characteristics, and gross calorific value (GCV) were evaluated as well as compared concerning the European standard specification for residential/commercial densified fuels. In addition, the quality of pellets was compared with coal. The results showed that the pellets made only with hydrothermally treated hospital solid waste, hydrothermally treated rice straw, pyrolytic plastic waste residue, and rice straw failed to meet few individual criteria (<3 wt% ash content, <10 wt% moisture content, <0.03 wt% chlorine content, >96.5 wt% pellet durability, and >600 kg/m3 pellet density) of the European standard specifications. However, most of the mixed fuel pellets satisfied the requirement of pellet properties according to the European standard specification. In particular, up to 16.70 wt% hydrothermally treated rice straw, 1.50 wt% hydrothermally treated hospital solid waste, and 4.76 wt% of pyrolytic plastic waste residue can be blended with Shakhalin fir residue to produce low-chlorine fuel pellets. The gross calorific value of pellets made from the mixture of hydrothermally treated wastes and pyrolytic plastic waste residue (around 22 MJ/kg) showed similar results to that of coal. In the case of mixed pellets, the presence of these hydrothermally treated wastes and pyrolytic plastic waste residue valorized the fuel pellet quality. The main outcome of this study was the production of low chlorine biomass fuel pellets of high gross calorific values blended with hydrothermally treated wastes and pyrolytic waste residues, which opens a new door for utilizing waste in a better way, especially hospital solid waste.
35
Zhang, L., A. Jhingan e FJ Castellino. "Role of individual gamma-carboxyglutamic acid residues of activated human protein C in defining its in vitro anticoagulant activity". Blood 80, n. 4 (15 agosto 1992): 942–52. http://dx.doi.org/10.1182/blood.v80.4.942.942.
Testo completoAbstract (sommario):
Abstract To evaluate the contributions of individual gamma-carboxyglutamic acid (gla) residues to the overall Ca(2+)-dependent anticoagulant activity of activated human protein C (APC), we used recombinant (r) DNA technology to generate protein C (PC) variants in which each of the gla precursor glutamic acid (E) residues (positions 6, 7, 14, 16, 19, 20, 25, 26, and 29) was separately altered to aspartic acid (D). In one case, a gla26V mutation ([gla26V]r-PC) was constructed because a patient with this particular substitution in coagulation factor IX had been previously identified. Two additional r-PC mutants were generated, viz, an r-PC variant containing a substitution at arginine (R) 15 ([R15]r-PC), because this particular R residue is conserved in all gla- containing blood coagulation proteins, as well as a variant r-PC with substitution of an E at position 32 ([F31L, Q32E]r-PC), because gla residues are found in other proteins at this sequence location. This latter protein did undergo gamma-carboxylation at the newly inserted E32 position. For each of the 11 recombinant variants, a subpopulation of PC molecules that were gamma-carboxylated at all nonmutated gla- precursor E residues has been purified by anion exchange chromatography and, where necessary, affinity chromatography on an antihuman PC column. The r-PC muteins were converted to their respective r-APC forms and assayed for their amidolytic activities and Ca(2+)-dependent anticoagulant properties. While no significant differences were found between wild-type (wt) r-APC and r-APC mutants in the amidolytic assays, lack of a single gla residue at any of the following locations, viz, 7, 16, 20, or 26, led to virtual complete disappearance of the Ca(2+)-dependent anticoagulant activity of the relevant r-APC mutant, as compared with its wt counterpart. On the other hand, single eliminations of any of the gla residues located at positions 6, 14, or 19 of r-APC resulted in variant recombinant molecules with substantial anticoagulant activity (80% to 92%), relative to wtr-APC. Mutation of gla residues at positions 25 and 29 resulted in r-APC variants with significant but low (24% and 9% of wtr-APC, respectively) levels of anticoagulant activity. The variant, [R15L]r-APC, possessed only 19% of the anticoagulant activity of wrt-APC, while inclusion of gla at position 32 in the variant, [F31L, Q32gla]r-APC, resulted in a recombinant enzyme with an anticoagulant activity equivalent to that of wtr-APC.
36
Zhang, L., A. Jhingan e FJ Castellino. "Role of individual gamma-carboxyglutamic acid residues of activated human protein C in defining its in vitro anticoagulant activity". Blood 80, n. 4 (15 agosto 1992): 942–52. http://dx.doi.org/10.1182/blood.v80.4.942.bloodjournal804942.
Testo completoAbstract (sommario):
To evaluate the contributions of individual gamma-carboxyglutamic acid (gla) residues to the overall Ca(2+)-dependent anticoagulant activity of activated human protein C (APC), we used recombinant (r) DNA technology to generate protein C (PC) variants in which each of the gla precursor glutamic acid (E) residues (positions 6, 7, 14, 16, 19, 20, 25, 26, and 29) was separately altered to aspartic acid (D). In one case, a gla26V mutation ([gla26V]r-PC) was constructed because a patient with this particular substitution in coagulation factor IX had been previously identified. Two additional r-PC mutants were generated, viz, an r-PC variant containing a substitution at arginine (R) 15 ([R15]r-PC), because this particular R residue is conserved in all gla- containing blood coagulation proteins, as well as a variant r-PC with substitution of an E at position 32 ([F31L, Q32E]r-PC), because gla residues are found in other proteins at this sequence location. This latter protein did undergo gamma-carboxylation at the newly inserted E32 position. For each of the 11 recombinant variants, a subpopulation of PC molecules that were gamma-carboxylated at all nonmutated gla- precursor E residues has been purified by anion exchange chromatography and, where necessary, affinity chromatography on an antihuman PC column. The r-PC muteins were converted to their respective r-APC forms and assayed for their amidolytic activities and Ca(2+)-dependent anticoagulant properties. While no significant differences were found between wild-type (wt) r-APC and r-APC mutants in the amidolytic assays, lack of a single gla residue at any of the following locations, viz, 7, 16, 20, or 26, led to virtual complete disappearance of the Ca(2+)-dependent anticoagulant activity of the relevant r-APC mutant, as compared with its wt counterpart. On the other hand, single eliminations of any of the gla residues located at positions 6, 14, or 19 of r-APC resulted in variant recombinant molecules with substantial anticoagulant activity (80% to 92%), relative to wtr-APC. Mutation of gla residues at positions 25 and 29 resulted in r-APC variants with significant but low (24% and 9% of wtr-APC, respectively) levels of anticoagulant activity. The variant, [R15L]r-APC, possessed only 19% of the anticoagulant activity of wrt-APC, while inclusion of gla at position 32 in the variant, [F31L, Q32gla]r-APC, resulted in a recombinant enzyme with an anticoagulant activity equivalent to that of wtr-APC.
37
Gockel, Hedwig E., Sami Alsindi, Charles Hardy e Robert P. Carlyon. "Effect of Context on the Contribution of Individual Harmonics to Residue Pitch". Journal of the Association for Research in Otolaryngology 18, n. 6 (28 luglio 2017): 803–13. http://dx.doi.org/10.1007/s10162-017-0636-6.
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Contreras, A., M. J. Paape, A. L. Di Carlo, R. H. Miller e P. Rainard. "Evaluation of Selected Antibiotic Residue Screening Tests for Milk from Individual Goats". Journal of Dairy Science 80, n. 6 (giugno 1997): 1113–18. http://dx.doi.org/10.3168/jds.s0022-0302(97)76037-5.
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Gdanov, Yu, e R. Nesmachnov. "Mechanization of forest residue removal and individual trees of protective forest plantations". Актуальные направления научных исследований XXI века: теория и практика 3, n. 2 (17 marzo 2015): 42–46. http://dx.doi.org/10.12737/10014.
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40
Dogheim, Salwa M., Sohair A. Gad Alla e Ashraf M. El-Marsafy. "Monitoring of Pesticide Residues in Egyptian Fruits and Vegetables During 1996". Journal of AOAC INTERNATIONAL 84, n. 2 (1 marzo 2001): 519–31. http://dx.doi.org/10.1093/jaoac/84.2.519.
Testo completoAbstract (sommario):
Abstract Samples of the most common fruits and vegetables were collected from 8 local markets in 6 governorates. These 1579 samples were analyzed for residues of 53 pesticides, which included organophosphorus and organonitrogen compounds and some synthetic pyrethroids. Samples were also analyzed for residues of organochlorine pesticides, although they had been prohibited from use several years ago. Only 510 of the 1579 samples were analyzed for dithiocarbamate pesticide residues, which were determined as CS2. Overall, 76.1% of the total analyzed samples had no detectable residues, 23.9% contained detectable residues, and 2.59% contained residues that exceeded maximum residue limits. For individual crops, contaminated samples ranged from 0 to 96% of the number of samples analyzed. However, the highest violative percentage for samples of individual crops was 12.5. Chlorpyrifos, carbaryl, dimethoate, bromopropylate, and profenofos were the violative pesticides determined in fruit and vegetable samples. The results of the current study demonstrated that no restricted or banned pesticides such as DDT, HCH, and their isomers were found in any of the samples analyzed. Dithiocarbamate residues were detected in 9.4% of the 510 samples analyzed, with a violative percentage of 0.39, representing one grape sample and one peach sample.
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Nguyen Dang Giang, Chau, Dang Bao Chau Le, Van Hop Nguyen, Thai Long Hoang, Thi Van Thi Tran, Thi Phuong Linh Huynh e Thi Quynh Trang Nguyen. "Assessment of pesticide use and pesticide residues in vegetables from two provinces in Central Vietnam". PLOS ONE 17, n. 6 (13 giugno 2022): e0269789. http://dx.doi.org/10.1371/journal.pone.0269789.
Testo completoAbstract (sommario):
Pesticide residue in food, especially in vegetables, is one of the important parameters to assess food safety. This study evaluates the pesticide use in vegetables from two provinces in Central Vietnamand and present data on pesticides detected in vegetables sampled from the sites. The potential health risk associated with the contamination of four commonly used pesticides in different vegetables is also discussed. Both household surveys and monitoring campaigns were conducted. The survey showed that improper pesticide application, storage, and waste disposal prevailed at the study sites. Only 20% of the respondent were aware of pesticide toxicity. As a result, pesticides were detected in 81% out of 290 vegetable samples collected at harvesting time. Up to 23% of samples had pesticide residues above the Maximum Residue Limit values. The highest total pesticide concentration quantified in vegetables in Thua Thien Hue was 11.9 mg/kg (green onions), and in Quang Binh was 38.6 mg/kg (mustard greens). Median residue levels of individual pesticides in vegetables ranged from 0.007 to 0.037 mg/kg. Among the ten target pesticides, cypermethrin, difenoconazole, and fenobucarb were detected at the highest frequencies (72%, 41%, and 37%, respectively). Pesticide residues varied between seasons at both study provinces. Pesticide contamination in the wet season was significantly higher than in the dry season. This study also discovered a potential health risk associated with fipronil residues in vegetables in Thua Thien Hue province. The paper provides recommendations for mitigation measures (both technological and social) in reducing potential health risks linked to pesticide use in vegetables in the region.
42
Moran, R. E., D. E. Deyton, C. E. Sams, J. Cummins e C. D. Pless. "Net CO2 Assimilation of Apple following Application of Soybean Oil". HortScience 32, n. 3 (giugno 1997): 531C—531. http://dx.doi.org/10.21273/hortsci.32.3.531c.
Testo completoAbstract (sommario):
Soybean oil can be used as an alternative pesticide for fruit trees. Two separate studies were conducted to determine the effects of oil concentration on leaf phytotoxicity and net CO2 assimilation (ACO2). In one study, concentrations of 0%, 2%, 4%, and 6% soybean oil in water were applied to individual shoots with a hand-held mist bottle. In the second study, 0%, 1.0%, and 1.5% were applied to whole trees with an airblast sprayer. Petroleum oil was applied as a separate treatment. Net CO2 assimilation was measured on single leaves. Oil residue was removed from the leaf with chloroform, dried, and weighed. Chlorosis and defoliation occurred with applications of 4% and 6% soybean oil. No visible phytotoxicity occurred with 2% or less oil. Net CO2 assimilation decreased as the rate of soybean oil increased from 0% to 4% oil, but there was no difference between 4% and 6%. Net CO2 assimilation decreased with increasing oil concentration from 0% to 1.5% and recovered to the rate of the control on day 7. Net CO2 assimilation was negatively related to oil residue. At an equivalent oil residue, there was no difference in ACO2 between petroleum and soybean oil. Below a residue of 0.15 mg·cm–2, foliar phytoxicity did not occur. Reductions in ACO2 were small and did not last longer than 7 days if residues were ≤0.10 mg·cm–2.
43
Chatterjee, Sunanda, Rituparna Sinha Roy e P. Balaram. "Expanding the polypeptide backbone: hydrogen-bonded conformations in hybrid polypeptides containing the higher homologues of α-amino acids". Journal of The Royal Society Interface 4, n. 15 (23 gennaio 2007): 587–606. http://dx.doi.org/10.1098/rsif.2006.0203.
Testo completoAbstract (sommario):
Half a century has passed since the hydrogen-bonded secondary structures of polypeptides and proteins were first recognized. An extraordinary wealth of conformational information is now available on peptides and proteins, which are formed of α-amino acid residues. More recently, the discovery of well-folded structures in oligopeptides containing β-amino acids has focused a great deal of current interest on the conformational properties of peptides constructed from higher homologues (ω) of α-amino acids. This review examines the nature of intramolecularly hydrogen-bonded conformations of hybrid peptides formed by amino acid residues, with a varying number of backbone atoms. The β-turn, a ubiquitous structural feature formed by two residue (αα) segments in proteins and peptides, is stabilized by a 10-atom (C 10 ) intramolecular 4→1 hydrogen bond. Hybrid turns may be classified by comparison with their αα counterparts. The available crystallographic information on hydrogen-bonded hybrid turns is surveyed in this review. Several recent examples demonstrate that individual ω-amino acid residues and hybrid dipeptide segments may be incorporated into the regular structures of α-peptides. Examples of both peptide helices and hairpins are presented. The present review explores the relationships between folded conformations in hybrid sequences and their counterparts in all α-residue sequences. The use of stereochemically constrained ω-residues promises to expand the range of peptide design strategies to include ω-amino acids. This approach is exemplified by well-folded structures like the C 12 (αγ) and C 14 (γγ) helices formed in short peptides containing multiply substituted γ-residues. The achiral γ-residue gabapentin is a readily accessible building block in the design of peptides containing γ-amino acids. The construction of globular polypeptide structures using diverse hybrid sequences appears to be a realistic possibility.
44
Myers, Sharon A., Troy D. Cognata e Hugh Gotts. "FTIR analysis of printed-circuit board residue". Proceedings, annual meeting, Electron Microscopy Society of America 54 (11 agosto 1996): 264–65. http://dx.doi.org/10.1017/s0424820100163782.
Testo completoAbstract (sommario):
Logic boards were failing at Enhanced Mac Minus One (EMMO) test or Integrated Circuit Test (ICT) after printed circuit board (PCB) rework. The failure to boot was originally traced to a suspected bad microcontroller chip. Replacing this chip, or an oscillator tied to the microcontroller circuit, did not consistently solve the boot problem. With further testing, it was found the microcontroller circuit was very sensitive to resistance and was essentially shorted.A resistor in the microcontroller circuit was identified on the flip side of the PCB. Several areas on the board, including the resistor R161, were seen to have a slight white haze/ low gloss appearance on the surface of the PCB. To test if the residue was electrically conductive, five boards were selected whose sole failure was R161. The resistance of the individual resistors was measured with a digital multimeter (DMM). The resistor was then cleaned with isopropyl alcohol and a cotton swab. Each board was retested at ICT and the individual resistors measured again with a DMM. Cleaning the area surrounding the resistor with isopropyl alcohol, corrected the failure four of the times.
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Henriksen, R. A., C. K. Dunham, L. D. Miller, J. T. Casey, J. B. Menke, C. L. Knupp e S. J. Usala. "Prothrombin Greenville, Arg517→Gln, Identified in an Individual Heterozygous for Dysprothrombinemia". Blood 91, n. 6 (15 marzo 1998): 2026–31. http://dx.doi.org/10.1182/blood.v91.6.2026.
Testo completoAbstract (sommario):
Abstract A 64-year-old white male was referred for evaluation of prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT) obtained before elective surgery with initial PT and PTT results of 14.9 and 38.4 seconds, respectively, which corrected to normal in 1:1 mixes with normal plasma. Functional prothrombin assay indicated a level of 51% with thromboplastin as an activator. The prothrombin antigen was 102%. This discordance in the functional and immunologic prothrombin levels was evidence for dysprothrombinemia. Western blotting showed that thrombin was formed at a normal rate in diluted plasma consistent with a mutation within the thrombin portion of prothrombin. DNA was isolated from leukocytes and the thrombin exons were amplified by polymerase chain reaction, cloned, and sequenced. For exon 13, eight clones were sequenced with four clones showing a point mutation in the codon for Arg517, which would result in substitution by Gln. Arg517 is part of the Arg-Gly-Asp(RGD) sequence in thrombin and contributes to an ion cluster with aspartic acid residues 552 and 554. Mutation at this residue most probably distorts the structure of the Na+ binding site in thrombin. This is the first report indicating the critical role of Arg517 in the normal physiological interaction of thrombin with fibrinogen. This dysprothrombin is designated Prothrombin Greenville.
46
Henriksen, R. A., C. K. Dunham, L. D. Miller, J. T. Casey, J. B. Menke, C. L. Knupp e S. J. Usala. "Prothrombin Greenville, Arg517→Gln, Identified in an Individual Heterozygous for Dysprothrombinemia". Blood 91, n. 6 (15 marzo 1998): 2026–31. http://dx.doi.org/10.1182/blood.v91.6.2026.2026_2026_2031.
Testo completoAbstract (sommario):
A 64-year-old white male was referred for evaluation of prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT) obtained before elective surgery with initial PT and PTT results of 14.9 and 38.4 seconds, respectively, which corrected to normal in 1:1 mixes with normal plasma. Functional prothrombin assay indicated a level of 51% with thromboplastin as an activator. The prothrombin antigen was 102%. This discordance in the functional and immunologic prothrombin levels was evidence for dysprothrombinemia. Western blotting showed that thrombin was formed at a normal rate in diluted plasma consistent with a mutation within the thrombin portion of prothrombin. DNA was isolated from leukocytes and the thrombin exons were amplified by polymerase chain reaction, cloned, and sequenced. For exon 13, eight clones were sequenced with four clones showing a point mutation in the codon for Arg517, which would result in substitution by Gln. Arg517 is part of the Arg-Gly-Asp(RGD) sequence in thrombin and contributes to an ion cluster with aspartic acid residues 552 and 554. Mutation at this residue most probably distorts the structure of the Na+ binding site in thrombin. This is the first report indicating the critical role of Arg517 in the normal physiological interaction of thrombin with fibrinogen. This dysprothrombin is designated Prothrombin Greenville.
47
Parmar, Abhijitsinh A., Rajesh G Babu e S. O. Junare. "Differentiation of high velocity ammunition type from Gunshot Residue (GSR) metal element originating from different firearm". International Journal of Chemistry, Mathematics and Physics 6, n. 2 (2022): 18–23. http://dx.doi.org/10.22161/ijcmp.6.2.2.
Testo completoAbstract (sommario):
The examination of GSR collected from the scene of occurrence is critical to the forensic science community because it provides answers to problems such as distinguishing between entry and exit wounds, estimating the range of fire, and linking an individual to the use of a firearm. Insufficient information exists on the differentiation of ammunition type through the analysis of GSR. This study investigated the potential of differentiating between ammunition types through the analysis of its metallic residue using Energy Dispersive X-Ray Fluorescence spectroscopy (EDXRF) and Scanning Electron Microscope Energy Dispersive X-Ray Fluorescence spectroscopy (SEM-EDS). Three firearms (AK-47 assault rifle, Self-loading rifle, and Carbine rifle) were adopted for the study. Overall, a series of 10 shots were performed from each firearm at three different collection mode (45°, 90° & Barrel wash) The residues were subjected to a non-destructive analysis by energy dispersive X-Ray fluorescence (EDXRF-7000, Shimadzu) without sample preparation and Scanning Electron Microscope Energy Dispersive X-Ray Fluorescence spectroscopy. Gunshot residues originating from 9mm Carbine, AK-47 and Self-loading rifle produced common metal element including Lead (Pb), Copper (Cu), Mercury (Hg), Antimony (Sb) and Zinc (Zn). Considering that, analysis of the sample residue was carried out EDXRF and SEM-EDS; it was unreliable to predict the ammunition type from the particles that originated from the firearm-ammunition employed. In this study element profile of Gunshot residue give some identical point which can helpful in identification of ammunition.
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Danon, Gradimir, Milosav Andjelic, Branko Glavonjic, Ratko Kadovic e Mladen Furtula. "Wood biomass for energy in Montenegro". Thermal Science 14, n. 3 (2010): 783–98. http://dx.doi.org/10.2298/tsci100217005d.
Testo completoAbstract (sommario):
Wood biomass has got its place in the energy balance of Montenegro. A little more than 6% of the total energy consumption is obtained by burning wood. Along with the appropriate state measures, it is economically and environmentally justified to expect Montenegro to more than double the utilization of the existing renewable energy sources including wood biomass, in the near future. For the purpose of achieving this goal, ?Commercial utilization of the Wood Residue as a Resource for Economic Development in the North of Montenegro? project was carried out in 2007. The results of this project were included in the plan of the necessary interventions of the Government and its Agencies, associations or clusters, non-government organizations and interested enterprises. The plan was made on the basis of the wood residue at disposal and the attitude of individual subjects to produce and/or use solid bio-fuels and consists of a proposal of collection and utilization of the wood residue for each individual district in the north of Montenegro. The basic factors of sustainability of future commercialization of the wood residue were: availability of the wood raw material, and thereby the wood residue; the development of wood-based fuel markets, and the size of the profit.
49
Hui, Kwokyin, Deane McIntyre e Robert J. French. "Conotoxins as Sensors of Local pH and Electrostatic Potential in the Outer Vestibule of the Sodium Channel". Journal of General Physiology 122, n. 1 (30 giugno 2003): 63–79. http://dx.doi.org/10.1085/jgp.200308842.
Testo completoAbstract (sommario):
We examined the block of voltage-dependent rat skeletal muscle sodium channels by derivatives of μ-conotoxin GIIIA (μCTX) having either histidine, glutamate, or alanine residues substituted for arginine-13. Toxin binding and dissociation were observed as current fluctuations from single, batrachotoxin-treated sodium channels in planar lipid bilayers. R13X derivatives of μCTX only partially block the single-channel current, enabling us to directly monitor properties of both μCTX-bound and -unbound states under different conditions. The fractional residual current through the bound channel changes with pH according to a single-site titration curve for toxin derivatives R13E and R13H, reflecting the effect of changing the charge on residue 13, in the bound state. Experiments with R13A provided a control reflecting the effects of titration of all residues on toxin and channel other than toxin residue 13. The apparent pKs for the titration of residual conductance are shifted 2–3 pH units positive from the nominal pK values for histidine and glutamate, respectively, and from the values for these specific residues, determined in the toxin molecule in free solution by NMR measurements. Toxin affinity also changes dramatically as a function of pH, almost entirely due to changes in the association rate constant, kon. Interpreted electrostatically, our results suggest that, even in the presence of the bound cationic toxin, the channel vestibule strongly favors cation entry with an equivalent local electrostatic potential more negative than −100 mV at the level of the “outer charged ring” formed by channel residues E403, E758, D1241, and D1532. Association rates are apparently limited at a transition state where the pK of toxin residue 13 is closer to the solution value than in the bound state. The action of these unique peptides can thus be used to sense the local environment in the ligand-–receptor complex during individual molecular transitions and defined conformational states.
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Yoshida, Toru, e Hideaki Tsuge. "Common Mechanism for Target Specificity of Protein- and DNA-Targeting ADP-Ribosyltransferases". Toxins 13, n. 1 (7 gennaio 2021): 40. http://dx.doi.org/10.3390/toxins13010040.
Testo completoAbstract (sommario):
Many bacterial pathogens utilize ADP-ribosyltransferases (ARTs) as virulence factors. The critical aspect of ARTs is their target specificity. Each individual ART modifies a specific residue of its substrates, which could be proteins, DNA, or antibiotics. However, the mechanism underlying this specificity is poorly understood. Here, we review the substrate recognition mechanism and target residue specificity based on the available complex structures of ARTs and their substrates. We show that there are common mechanisms of target residue specificity among protein- and DNA-targeting ARTs.