Wykorzystanie technik data mining w analizowaniu czynników wpływających na reaktywność krów podczas doju

Motor activity of 158 Polish Holstein-Friesian cows was evaluated 5 times (before and during milking in a DeLaval 2*10 milking parlour) for both the morning and evening milking, on a 5-point scale, according to the method of Budzyńska et al. (2007). The statistical analysis used multiple logistic regression and classification trees (Enterprise Miner 7.1 software which comes in with SAS package). In the evaluation of motor activity, cows that were among the first ten to enter the milking parlour were more often given a score of 3 points before (11.5%) and during milking (23.5%) compared to the other cows. Cows’ activity tended to decrease (both before and during milking) with advancing lactation. The cows’ reduced activity was accompanied by shorter teat cup attachment times and lower milk yields. The criteria calculated for the quality of models based on classification tree technique as well as logistic regression showed that similar variables were responsible for the reactivity of cows before milking (teat cup attachment time, day of lactation, number of lactation, side of the milking parlour) and during milking (day of lactation, side of the milking parlour, morning or evening milking, milk yield, number of lactation). At the same time, the applied methods showed that the determinants of the cow reactivity trait are highly complex. This complexity may be well explained using the classification tree technique.Aktywność ruchową (przed i w czasie doju w hali udojowej DeLaval 2 * 10) 158 krów phf oceniono 5-krotnie, uwzględniając każdorazowo dój ranny i wieczorny, w skali 5 pkt., według metodyki Budzyńskiej i wsp. (2007). W opracowaniu statystycznym wykorzystano wieloraką regresję logistyczną i drzewa klasyfikacyjne (oprogramowanie Enterprise Miner 7.1 wchodzące w skład pakietu SAS). Stwierdzono, że krowy, które wchodziły do hali udojowej w pierwszej dziesiątce, w ocenie aktywności ruchowej przed i podczas doju częściej (11,5% oraz 23,5%) niż w przypadku pozostałych uzyskiwały 3 pkt. Odnotowano tendencję do zmniejszenia aktywności ruchowej krów (zarówno przed jak i w czasie doju) wraz z zaawansowaniem laktacji. Wykazano, że w wraz z mniejszą aktywnością ruchową krów skracał się czas zakładania kubków udojowych, jednocześnie też zmniejszała się wydajność mleka. Obliczone kryteria jakości modeli budowanych w oparciu o technikę drzew klasyfikacyjnych oraz regresji logistycznej wskazały podobne zmienne odpowiedzialne za reaktywność krów przed (czas zakładania kubków, kolejny dzień laktacji, kolejna laktacja i zajmowana strona hali udojowej) i w trakcie doju (kolejny dzień laktacji, zajmowana strona hali udojowej, dój ranny lub wieczorny, wydajność mleka oraz kolejna laktacja). Jednocześnie zastosowane metody wskazały znaczną złożoność uwarunkowania cechy, jak jest reaktywność krów. Złożoność ta może być dobrze wyjaśniona za pomocą techniki drzew klasyfikacyjnych

Interactions of Zn(II) Ions with Three His-Containing Peptide Models of Histone H2A

The interactions of Zn(ll) ions with the blocked hexapeptide models -TESHHK-, -TASHHK- and -TEAHHK- of the -ESHH- motif of the C-terminal of historic H2A were studied by using potentiometric and IH-NMR techniques. The first step of these studies was to compare the pKa values of the two His residues inside each hexapeptide calculated by potentiometric or H-NMR titrations. Hereafter, the potentiometric titrations in the pH range 5 11 suggest the formation of several monomeric Zn(ll) complexes. It was found that all hexapeptides bind to Zn(ll) ions initially through both imidazole nitrogens in weakly acidic and neutral solutions forming slightly distorted octahedral complexes. At higher pH values, the combination of potentiometric titrations and one and two dimensional NMR suggested no amide coordination in the coordination sphere of Zn(II) ions. Obviously, these studies support that the -ESHH- sequence of histone H2A is a potential binding site for Zn(II) ions similarly with the Cu(II) and Ni(ll) ions, presented in previous papers

An overlooked hepcidin-cadmium connection

Hepcidin (DTHFPICIFCCGCCHRSKCGMCCKT), an iron-regulatory hormone, is a 25-amino-acid peptide with four intramolecular disulfide bonds circulating in blood. Its hormonal activity is indirect and consists of marking ferroportin-1 (an iron exporter) for degradation. Hepcidin biosynthesis involves the N-terminally extended precursors prepro-hepcidin and pro-hepcidin, processed by peptidases to the final 25-peptide form. A sequence-specific formation of disulfide bonds and export of the oxidized peptide to the bloodstream follows. In this study we considered the fact that prior to export, reduced hepcidin may function as an octathiol ligand bearing some resemblance to the N-terminal part of the �-domain of metallothioneins. Consequently, we studied its ability to bind Zn(II) and Cd(II) ions using the original peptide and a model for prohepcidin extended N-terminally with a stretch of five arginine residues (5R-hepcidin). We found that both form equivalent mononuclear complexes with two Zn(II) or Cd(II) ions saturating all eight Cys residues. The average affinity at pH 7.4, determined from pH-metric spectroscopic titrations, is 10^10.1 M^-1 for Zn(II) ions; Cd(II) ions bind with affinities of 10^15.2 M^-1 and 10^14.1 M^-1. Using mass spectrometry and 5R-hepcidin we demonstrated that hepcidin can compete for Cd(II) ions with metallothionein-2, a cellular cadmium target. This study enabled us to conclude that hepcidin binds Zn(II) and Cd(II) sufficiently strongly to participate in zinc physiology and cadmium toxicity under intracellular conditions

Retinoic acid receptor beta protects striatopallidal medium spiny neurons from mitochondrial dysfunction and neurodegeneration

Retinoic acid is a powerful regulator of brain development, however its postnatal functions only start to be elucidated. We show that retinoic acid receptor beta (RAR beta), is involved in neuroprotection of striatopallidal medium spiny neurons (spMSNs), the cell type affected in different neuropsychiatric disorders and particularly prone to degenerate in Huntington disease (HD). Accordingly, the number of spMSNs was reduced in the striatum of adult Rar beta(-/-) mice, which may result from mitochondrial dysfunction and neurodegeneration. Mitochondria morphology was abnormal in mutant mice whereas in cultured striatal Rar beta(-/-) neurons mitochondria displayed exacerbated depolarization, and fragmentation followed by cell death in response to glutamate or thapsigargininduced calcium increase. In vivo, Rar beta(-/-)spMSNs were also more vulnerable to the mitochondrial toxin 3-nitropropionic acid (3NP), known to induce HD symptoms in human and rodents. In contrary, an RAR beta agonist, AC261066, decreased glutamate-induced toxicity in primary striatal neurons in vitro, and diminished mitochondrial dysfunction, spMSN cell death and motor deficits induced in wild type mice by 3NP. We demonstrate that the striatopallidal pathway is compromised in Rar beta(-/-) mice and associated with HD-like motor abnormalities. Importantly, similar motor abnormalities and selective reduction of spMSNs were induced by striatal or spMSNspecific inactivation of RAR beta, further supporting a neuroprotective role of RAR beta in postnatal striatum

Application of Ni(II)-Assisted Peptide Bond Hydrolysis to Non-Enzymatic Affinity Tag Removal

In this study, we demonstrate a non-enzymatic method for hydrolytic peptide bond cleavage, applied to the removal of an affinity tag from a recombinant fusion protein, SPI2-SRHWAP-His6. This method is based on a highly specific Ni(II) reaction with (S/T)XHZ peptide sequences. It can be applied for the protein attached to an affinity column or to the unbound protein in solution. We studied the effect of pH, temperature and Ni(II) concentration on the efficacy of cleavage and developed an analytical protocol, which provides active protein with a 90% yield and ∼100% purity. The method works well in the presence of non-ionic detergents, DTT and GuHCl, therefore providing a viable alternative for currently used techniques

Differential expression of retinoid receptors in the adult mouse central nervous system

International audienceThe immunocytochemical distribution of retinoid receptors has been analysed in the mouse adult central nervous system. All retinoic acid receptors (alpha, beta and gamma) and retinoid X receptors (alpha, beta and gamma) were detected and found to exhibit specific patterns of expression in various areas of the telencephalon, diencephalon and rhombencephalon. The protein localization of several retinoic acid receptors and retinoid X receptors did not correlate with the distribution of the corresponding RNA transcripts, as studied by in situ hybridization and RNase protection assays. This suggests that the expression of retinoid receptors could be post-transcriptionally regulated, which may contribute to their specific localization in the adult nervous system

9-Cis-13,14-dihydroretinoic acid, a new endogenous mammalian ligand of retinoid X receptor and the active ligand of a potential new vitamin A category: vitamin A5

The identity of the endogenous RXR ligand has not been conclusively determined, even though several compounds of natural origin, including retinoids and fatty acids, have been postulated to fulfill this role. Filling this gap, 9-cis-13,14-dihydroretinoic acid (9CDHRA) was identified as an endogenous RXR ligand in mice. This review examines the physiological relevance of various potential endogenous RXR ligands, especially 9CDHRA. The elusive steps in the metabolic synthesis of 9CDHRA, as well as the nutritional/nutrimetabolic origin of 9CDHRA, are also explored, along with the suitability of the ligand to be the representative member of a novel vitamin A class (vitamin A5)