1,272 research outputs found
Yield, forage quality, residue nitrogen and nitrogen fixation of different forage legumes
Fixed nitrogen accumulated by legumes is the main nitrogen source for organic farming systems. Knowledge about the amount of fixed nitrogen, its pathways into forage yield, crop residues, soil-N and yield formation of the following crop is needed for designing crop rotations.
In a field experiment conducted in Northern Germany differently managed (cut, mulched) legumes (red clover, alfalfa, white clover) in pure stands and in mixture with a companion grass (Lolium perenne) have been grown to determine Yield, forage-quality, N2-fixation and residue nitrogen.
Cropped grass/legume reached higher N2-fixation than mulched. While green manure grass/legume left up to 296 kg ha-1 of N in mulch, stubble and roots on the field, most cropped grass/legume mixtures left less than 120 kg N ha-1 in crop residues. Cropped swards showed higher N2-fixation than the mulched mixtures. Swards with red clover or alfalfa reached higher legume contents and harvestable biomass than swards with white clover.
Conclusions
The results show that biomass production, forage yields, residue nitrogen and N fixation of grass/legume mixtures can be influenced by various combinations of legume species and management. The factors listed have to be considered carefully when planning crop rotations
Towards quantitative prediction of proteasomal digestion patterns of proteins
We discuss the problem of proteasomal degradation of proteins. Though
proteasomes are important for all aspects of the cellular metabolism, some
details of the physical mechanism of the process remain unknown. We introduce a
stochastic model of the proteasomal degradation of proteins, which accounts for
the protein translocation and the topology of the positioning of cleavage
centers of a proteasome from first principles. For this model we develop the
mathematical description based on a master-equation and techniques for
reconstruction of the cleavage specificity inherent to proteins and the
proteasomal translocation rates, which are a property of the proteasome specie,
from mass spectroscopy data on digestion patterns. With these properties
determined, one can quantitatively predict digestion patterns for new
experimental set-ups. Additionally we design an experimental set-up for a
synthetic polypeptide with a periodic sequence of amino acids, which enables
especially reliable determination of translocation rates.Comment: 14 pages, 4 figures, submitted to J. Stat. Mech. (Special issue for
proceedings of 5th Intl. Conf. on Unsolved Problems on Noise and Fluctuations
in Physics, Biology & High Technology, Lyon (France), June 2-6, 2008
Audits and inspections of pharmacovigilance systems in Russia
The implementation of pharmacovigilance activities is impossible in isolation from compliance with the quality requirements of medicines and the activities of pharmaceutical and medical organizations throughout the pharmaceutical practice, as well as without access to sales plans, sales results and full relevance of information on drug conditions in all markets and in all cases of application. Properly conducted audit or inspection evaluation of the pharmacovigilance system makes it possible to identify and prevent drug safety problems at all stages of its life cycle.The aim. Development of a risk-based strategy for planning and passing audits and inspections of the pharmacovigilance system for the subsequent creation of effective programs for assessing the pharmacovigilance system on its basis.Material and methods. The study used structurallogical, empirical methods, general logical methods of scientific knowledge, methods of generalization and extrapolation.Results. The plans and results of audits and inspections of pharmacovigilance systems of Russian and foreign pharmaceutical organizations and their pharmacovigilance vendors were analyzed. A risk-based strategy and a checklist for planning internal and external audits of pharmacovigilance systems of Russian pharmaceutical organizations and their vendors for pharmacovigilance have been developed and recommendations for training internal auditors of pharmacovigilance systems and audit teams have been developed for them.Conclusion. Risk assessment indicators adapted for Russia have been developed, according to which Russian pharmaceutical organizations and their pharmacovigilance vendors can assess the likelihood of the risk of priority inclusion in the plan of Russian inspections of pharmacovigilance systems for compliance with the requirements of the good pharmacovigilance practice of the Eurasian Economic Union. Recommendations were prepared for the executive management and pharmacovigilance specialists of Russian pharmaceutical organizations in terms of assessing regulatory risks for the quality system of the pharmacovigilance system, planning and conducting audits; evaluating the relationship of pharmacovigilance with other good practices and with information from the plans and results of the organization as a whole. The indicators adapted for Russia for assessing the compliance of the pharmacovigilance system with the rules of the NPF EAEU are given
The T210M Substitution in the HLA-a*02:01 gp100 Epitope Strongly Affects Overall Proteasomal Cleavage Site Usage and Antigen Processing
MHC class I-restricted epitopes, which carry a tumor-specific mutation resulting in improved MHC binding affinity, are preferred T cell receptor targets in innovative adoptive T cell therapies. However, T cell therapy requires efficient generation of the selected epitope. How such mutations may affect proteasome-mediated antigen processing has so far not been studied. Therefore, we analyzed by in vitro experiments the effect on antigen processing and recognition of a T210M exchange, which previously had been introduced into the melanoma gp100209–217tumor epitope to improve the HLA-A*02:01 binding and its immunogenicity. A quantitative analysis of the main steps of antigen processing shows that the T210M exchange affects proteasomal cleavage site usage within the mutgp100201–230 polypeptide, leading to the generation of an unique set of cleavage products. The T210M substitution qualitatively affects the proteasome-catalyzed generation of spliced and non-spliced peptides predicted to bind HLA-A or -B complexes. The T210M substitution also induces an enhanced production of the mutgp100209–217 epitope and its N-terminally extended peptides. The T210M exchange revealed no effect on ERAP1-mediated N-terminal trimming of the precursor peptides. However, mutant N-terminally extended peptides exhibited significantly increased HLA-A*02:01 binding affinity and elicited CD8+ T cell stimulation in vitro similar to the wtgp100209–217 epitope. Thus, our experiments demonstrate that amino acid exchanges within an epitope can result in the generation of an altered peptide pool with new antigenic peptides and in a wider CD8+ T cell response also towards N-terminally extended versions of the minimal epitope
Diverse Forage Mixtures Effect on Herbage Yield, Sward Composition, and Dairy Cattle Performance
Managing complex mixtures of plants to take advantage of spatial and temporal variability in land and climate may be one ecological approach to increase productivity of pastures. We tested the hypothesis that complex mixtures of forage species would yield more herbage and reduce weed competition compared with a simple grass-legume mixture in grazed pastures
The domain swapping of human cystatin C induced by synchrotron radiation
Domain swapping is observed for many proteins with flexible conformations. This phenomenon is often associated with the development of conformational diseases. Importantly, domain swapping has been observed for human cystatin C (HCC), a protein capable of forming amyloid deposits in brain arteries. In this study, the ability of short exposure to high-intensity X-ray radiation to induce domain swapping in solutions of several HCC variants (wild-type HCC and V57G, V57D, V57N, V57P, and L68V mutants) was determined. The study was conducted using time-resolved small-angle X-ray scattering (TR-SAXS) synchrotron radiation. The protein samples were also analysed using small-angle neutron scattering and NMR diffusometry. Exposing HCC to synchrotron radiation (over 50 ms) led to a gradual increase in the dimeric fraction, and for exposures longer than 150 ms, the oligomer fraction was dominant. In contrast, the non-irradiated protein solutions, apart from the V57P variant, were predominantly monomeric (e.g., V57G) or in monomer/dimer equilibrium. This work might represent the first observation of domain swapping induced by high-intensity X-rays
Impact of Grazing Intensity on Feed Intake, Herbage Mass, and Animal Productivity in the Steppe of Inner Mongolia, China
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