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Localization of urea transporter B in the developing bovine rumen

Animal Nutrition 2022年第3期10卷 216-222页

作者： Chongliang Zhong Tamsin Lyons Orla Heussaff Evelyn Doyle Eoin O'Hara Sinead M.Waters david kenny Gavin S.Stewart School of Biology and Environmental Science University College DublinBelfieldDublin 4Ireland Animal and Bioscience Research Department Animal and Grassland Research and Innovation CentreTeagascGrangeCounty MeathIreland Department of Agriculture Foodand Nutritional SciencesUniversity of AlbertaEdmontonAlbertaCanada

Urea nitrogen secreted from blood to rumen is a crucial factor shaping the symbiotic relationship between host ruminants and their microbial *** of urea across rumen epithelia is facilitated by urea transporter B(UT-B),but the long-term regulation of these proteins remains *** ruminal function develops over a period of months,the developing rumen is an excellent model with which to investigate this *** rumen epithelium samples of calves from birth to 96 d of age,this study performed immunolocalization studies to localize and semi-quantify UT-B protein *** expected,preliminary experiments confirmed that ruminal monocarboxylate transporter 1(MCT1)short chain fatty acid transporter protein abundance increased with age(P<0.01,n=4).Further investigation revealed that ruminal UT-B was present in the first few weeks of life and initially detected in the basolateral membrane of stratum basale *** the next 2 months,UT-B staining spread to other epithelial layers and semi-quantification indicated that UT-B abundance significantly increased with age(P<0.01,n=4 or 6).These changes were in line with the development of rumen function after the advent of solid feed intake and weaning,exhibiting a similar pattern to both MCT1 transporters and papillae *** study therefore confirmed age-dependent changes of in situ ruminal UT-B protein,adding to our understanding of the long-term regulation of ruminal urea transporters.

关键词： UT-B Immunolocalization Rumen Bovine Development

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Quantitative analysis of ruminal methanogenic microbial populations in beef cattle divergent in phenotypic residual feed intake(RFI)offered contrasting diets

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Journal of Animal Science and Biotechnology 2014年第4期5卷 439-447页

作者： Ciara A Carberry david A kenny Alan K Kelly Sinead M Waters Animal and Bioscience Research Department Animal and Grassland Research and Innovation CentreTeagascGrangeDunsanyCo.MeathIreland UCD School of Agriculture Food Science and Veterinary MedicineCollege of Life SciencesUniversity College DublinBelfieldDublin 4Ireland

Background：Methane（CH_4） emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed *** aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake（RFI） while offered（i） a low energy high forage（HF） diet followed by（ii） a high energy low forage（LF） *** fluid was collected from 14 high（H）and 14 low（L） RFI animals across both dietary *** real time PCR（qRT-PCR） analysis was conducted to quantify the abundance of total and specific rumen methanogenic *** correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance,rumen fermentation variables and diet ***：Abundance of methanogens,did not differ between RFI ***,relative abundance of total and specific methanogen species was affected（P〈 0.05） by diet type,with greater abundance observed while animals were offered the LF compared to the HF ***：These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH_4 emissions between efficient and inefficient animals,however dietary manipulation can influence the abundance of total and specific methanogen species.

关键词： Bovine qRT-PCR Residual feed intake Rumen methaongens

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Effect of genotype on duodenal expression of nutrient transporter genes in dairy cows

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Journal of Animal Science and Biotechnology 2014年第2期5卷 145-153页

作者： Sinéad M Waters Kate Keogh Frank Buckley david A kenny Teagasc Animal and Bioscience Research Department Animal and Grassland Research and Innovation CentreGrangeDunsanyCo.MeathIreland Teagasc Animal and Bioscience Research Department Animal and Grassland Research and Innovation Centre MooreparkFermoyCo CorkIreland

Background： Studies have shown clear differences between dairy breeds in their feed intake and production efficiencies. The duodenum is critical in the coordination of digestion and absorption of nutrients. This study examined gene transcript abundance of important classes of nutrient transporters in the duodenum of non lactating dairy cows of different feed efficiency potential, namely Holstein-Friesian （HF）, Jersey （JE） and their F1 hybrid. Duodenal epithelial tissue was collected at slaughter and stored at -80℃. Total RNA was extracted from tissue and reverse transcribed to generate cDNA. Gene expression of the following transporters, namely nucleoside amino acid; sugar; mineral; and lipid transporters was measured using quantitative real-time RT-PCR. Data were statistically analysed using mixed models ANOVA in SAS. Orthogonal contrasts were used to test for potential heterotic effects and spearman correlation coefficients calculated to determine potential associations amongst gen, expression values and production efficiency variables. Results： While there were no direct effects of genotype on expression values for any of the genes examined, there was evidence for a heterotic effect （P 〈 0.05） on ABCGS, in the form of increased expression in the F1 genotype compared to either of the two parent breeds. Additionally, a tendency for increased expression of the amino acid transporters, SLC3A1 （P= 0.072）, SLC3A2 （P= 0.081） and SLC6A 14 （P= 0.072） was also evident in the F1 genotype. A negative （P 〈 0.05） association was identified between the expression of the glucose transporter gene SLCSA1 and total lactational milk solids yield, corrected for body weight. Positive correlations （P 〈 0.05） were also observed between the expression values of genes involved in common transporter roles. Conclusion： This study suggests that differences in the expression of sterol and amino acid transporters in the duodenum could contribute towards the documented differences in feed effic

关键词： Bovine Duodenum Gene expression Nutrient transporters

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Examination of the molecular control of ruminal epithelial function in response to dietary restriction and subsequent compensatory growth in cattle

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Journal of Animal Science and Biotechnology 2017年第1期8卷 107-118页

作者： Emma O＇Shea Sinead M. Waters Kate Keogh Alan K. Kelly david A. kenny School of Agriculture and Food Science University College DublinBelfield Dublin 4Ireland Animal and Bioscience Research Department Animal & Grassland Research and Innovation Centre Teagasc Grange Dunsany Co Meath Ireland UCD Earth Institute University College Dublin Belfield Dublin 4 Ireland

Background： The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolism and cell proliferation in ruminal epithelial tissue of beef cattle. Sixty Holstein Friesian bulls（mean liveweight 370 ± 35 kg;mean age 479 ± 15 d） were assigned to one of two groups：（i） restricted feed allowance（RES; n = 30） for 125 d（Period 1） followed by ad libitum access to feed for 55 d（Period 2） or（ii） ad libitum access to feed throughout（ADLIB; n = 30）. Target growth rate for RES was 0.6 kg/d during Period 1. At the end of each dietary period, 15 animals from each treatment group were slaughtered and ruminal epithelial tissue and liquid digesta harvested from the ventral sac of the rumen. Real-time q PCR was used to quantify m RNA transcripts of 26 genes associated with ruminal epithelial function. Volatile fatty acid analysis of rumen fluid from individual animals was conducted using gas ***： Diet × period interactions were evident for genes involved in ketogenesis（BDH2, P = 0.017）, pyruvate metabolism（LDHa, P = 0.048; PDHA1, P = 0.015） and cellular transport and structure（DSG1, P = 0.019; CACT, P = 0.027）. Ruminal concentrations of propionic acid（P = 0.018） and n-valeric acid（P = 0.029） were lower in RES animals, compared with ADLIB, throughout the experiment. There was also a strong tendency（P = 0.064）toward a diet × period interaction for n-butyric with higher concentrations in RES animals, compared with ADLIB, during Period ***： These data suggest that following nutrient restriction, the structural integrity of the rumen wall is compromised and there is upregulation of genes involved in the production of ketone bodies and breakdown of pyruvate for cellular energy. These results provide an insight into the potential molecular mechanisms regulating ruminal epithelial absorptive metabolism and growth following nutri

关键词： Beef cattle Compensatory growth Feed efficiency Nutrient restriction Rumen epithelium

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Late Ordovician Mass Extinction: Earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： david A.T.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. These symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

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One-dimensional monotone nonautonomous dynamical systems

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Science China Mathematics 2024年第2期67卷 281-314页

作者： david Cheban Faculty of Mathematics and Computer Science Laboratory of Fundamental and Applied MathematicsMoldova State UniversityChisinau 2009Moldova

This work is devoted to the study of the dynamics of one-dimensional monotone nonautonomous(cocycle) dynamical systems. A description of the structures of their invariant sets, omega limit sets,Bohr/Levitan almost periodic and almost automorphic motions, global attractors, and pinched and minimalsets is given. An application of our general results is given to scalar differential and difference equations.

关键词： one-dimensional dynamics pinched and minimal sets global attractors monotone nonautonomous cocycle almost periodic solutions scalar differential/difference equations

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Kerogen Kinetic Distributions and Simulations Provide Insights into Petroleum Transformation Fraction (TF) Profiles of Organic-Rich Shales

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Journal of Earth Science 2024年第3期35卷 747-757页

作者： david A.Wood DWA Energy Limited Lincoln LN59JPUnited Kingdom

Two hundred and fifty single first-order Arrhenius reactions are simulated to generate S2 pyrograms at three heating rates 25,15,and 5°C·*** activation energy(E)and pre-exponential factor(A)of the reactions simulated follow a long-established trend of those variable values displayed by shales and *** characteristics of the transformation fraction(TF)profiles(product generation window temperatures)of the simulated single reactions are compared to the TF profiles of recorded shale pyrograms generated by multiple reactions with different E-A values lying near the defined E-A *** similarities and differences are observed between the TF profile values of the two *** similarities support the spread of E-A values involved in shale pyrogram best *** differences are most likely explained by the complexity of the multiple kerogen first-order and second-order reactions contributing to the recorded shale pyrograms versus the simplicity and crispness of the single first-order reactions *** results also justify the validity of using the previously described“variable E-A pyrogram-fitting method”of multi-heating-rate shale pyrograms enabling optimizers to choose multiple reactions from an unlimited range of E-A *** contrast,further doubt is cast on the validity of the constant-A pyrogram-fitting method used by the Easy%Ro technique,in that a distribution of reactions with a single A value is unlikely to represent the complex variety of kerogen macerals observed in shale *** profiles generated by the variable E-A pyrogram-fitting method lie close to the established E-A trend and are likely to provide more realistic TF generation window temperatures than TF profiles generated by the constant-A pyrogram-fitting method.

关键词： transformation fraction profiles simulated S2 pyrograms multiple heating rates kerogen/shale kinetics S2 pyrogram fitting techniques kerogen petroleum research.

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Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： david J.Bottjer Department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Discovery of strong bulk Dzyaloshinskii-Moriya interaction in composition-uniform centrosymmetric magnetic single layers

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 174-180页

作者： Lijun Zhu david Lujan Xiaoqin Li State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China Department of Physics Center for Complex Quantum SystemsUniversity of Texas at AustinAustin 78712USA

Dzyaloshinskii-Moriya interaction(DMI)is the key ingredient of chiral spintronic phenomena and the emerging technologies based on such phenomena.A nonzero DMI usually occurs at magnetic interfaces or within non-centrosymmetric single ***,we report the observation of a strong unexpected DMI within a centrosymmetric polycrystalline ferromagnet that has neither a crystal inversion symmetry breaking nor a composition *** DMI is a bulk effect,increases with the thickness of the magnetic layer,and is insensitive to the symmetry of the interfaces or the neighboring *** observe a total DMI strength that is a factor of>2 greater than the highest interfacial DMI in the *** DMI most likely arises from the strong spin-orbit coupling,strong orbital hybrization,and a“hidden”long-range asymmetry in the *** discovery of the strong unconventional bulk DMI in centrosymmetric,composition-uniform magnetic single layers provides fundamental building blocks for the emerging field of spintronics and will stimulate the exploitation of unconventional spin-orbit phenomena in a wide range of materials.

关键词： Brillouin light scattering Dzyaloshinskii-Moriya interaction spin wave

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The role of N-glycosylation in cancer

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Acta Pharmaceutica Sinica B 2024年第3期14卷 1098-1110页

作者： Yu Lin david M.Lubman Department of Surgery University of Michigan Medical CenterAnn ArborMI 48109USA

Despite advances in understanding the development and progression of cancer in recent years,there remains a lack of comprehensive characterization of the cancer *** play an important role in medicine and are involved in various human disease conditions including ***-moieties participate in fundamental cancer processes like cell signaling,invasion,angiogenesis,and *** N-glycosylation significantly impacts cancer processes and targeted therapies in ***,understanding N-glycosylation in a tumor is essential for comprehending disease progression and discovering anti-cancer targets and biomarkers for therapy monitoring and *** review presents the fundamental process of protein N-glycosylation and summarizes glycosylation changes in tumor cells,including increased terminal sialylation,N-glycan branching,and ***,the role of N-glycosylation in tumor signaling pathways,migration,and metabolism are *** and glycopeptides as potential biomarkers for early detection of cancer based on site specificity have been ***,understanding and exploring the cancer glycoproteome,along with its role in medicine,implication in cancer and other human diseases,highlights the significance of N-glycosylation in tumor processes,necessitating further research for potential anticancer targets and biomarkers.

关键词： N-Glycosylated proteins Cancer signaling Cancer angiogenesis Cancer metabolism Cancer biomarkers

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