292 research outputs found

    EFFECTS OF MILK UREA NITROGEN AND OTHER FACTORS ON PROBABILITY OF CONCEPTION OF DAIRY COWS

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    The objective of the present study was to evaluate the relationships among milk urea nitrogen (MUN) and other factors with the probability of conception in dairy cows. A total of 713 dairy herds and 10,271 dairy cows were included in the study. Logistic regression was used to determine the effects of MUN, milk production, lactation number, and breeding season on the probability of conception for each of three services. Within herds, MUN displayed a slight negative association with probability of conception at first service. In among-herd regression analysis, there was no effect of MUN on probability of conception. These results suggest that MUN may be related to conditions affecting reproduction of individual cows within a herd. Diet formulation usually would affect MUN equally among all cows at a similar stage of lactation in a herd. Since there was no effect of MUN among herds, diet formulation to meet the protein requirements did not appear to affect conception rate

    Noninfectious retrovirus particles drive the APOBEC3/Rfv3 dependent neutralizing antibody response.

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    Members of the APOBEC3 family of deoxycytidine deaminases counteract a broad range of retroviruses in vitro through an indirect mechanism that requires virion incorporation and inhibition of reverse transcription and/or hypermutation of minus strand transcripts in the next target cell. The selective advantage to the host of this indirect restriction mechanism remains unclear, but valuable insights may be gained by studying APOBEC3 function in vivo. Apobec3 was previously shown to encode Rfv3, a classical resistance gene that controls the recovery of mice from pathogenic Friend retrovirus (FV) infection by promoting a more potent neutralizing antibody (NAb) response. The underlying mechanism does not involve a direct effect of Apobec3 on B cell function. Here we show that while Apobec3 decreased titers of infectious virus during acute FV infection, plasma viral RNA loads were maintained, indicating substantial release of noninfectious particles in vivo. The lack of plasma virion infectivity was associated with a significant post-entry block during early reverse transcription rather than G-to-A hypermutation. The Apobec3-dependent NAb response correlated with IgG binding titers against native, but not detergent-lysed virions. These findings indicate that innate Apobec3 restriction promotes NAb responses by maintaining high concentrations of virions with native B cell epitopes, but in the context of low virion infectivity. Finally, Apobec3 restriction was found to be saturable in vivo, since increasing FV inoculum doses resulted in decreased Apobec3 inhibition. By analogy, maximizing the release of noninfectious particles by modulating APOBEC3 expression may improve humoral immunity against pathogenic human retroviral infections

    Lysine-specific demethylase 5C promotes hepatocellular carcinoma cell invasion through inhibition BMP7 expression

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    The primers used for the amplification of the indicated genes.(DOCX 17 kb

    Cellular HIV-1 inhibition by truncated old world primate APOBEC3A proteins lacking a complete deaminase domain

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    AbstractThe APOBEC3 (A3) deaminases are retrovirus restriction factors that were proposed as inhibitory components of HIV-1 gene therapy vectors. However, A3 mutational activity may induce undesired genomic damage and enable HIV-1 to evade drugs and immune responses. Here, we show that A3A protein from Colobus guereza (colA3A) can restrict HIV-1 replication in producer cells in a deaminase-independent manner without inducing DNA damage. Neither HIV-1 reverse transcription nor integration were significantly affected by colA3A, but capsid protein synthesis was inhibited. The determinants for colA3A restriction mapped to the N-terminal region. These properties extend to A3A from mandrills and De BrazzaΧ³s monkeys. Surprisingly, truncated colA3A proteins expressing only the N-terminal 100 amino acids effectively exclude critical catalytic regions but retained potent cellular restriction activity. These highlight a unique mechanism of cellular HIV-1 restriction by several Old World monkey A3A proteins that may be exploited for functional HIV-1 cure strategies

    A Single Nucleotide Polymorphism in Tetherin Promotes Retrovirus Restriction In Vivo

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    Tetherin is a membrane protein of unusual topology expressed from rodents to humans that accumulates enveloped virus particles on the surface of infected cells. However, whether this β€˜tethering’ activity promotes or restricts retroviral spread during acute retrovirus infection in vivo is controversial. We report here the identification of a single nucleotide polymorphism in the Tetherin gene of NZW/LacJ (NZW) mice that mutated the canonical ATG start site to GTG. Translation of NZW Tetherin from downstream ATGs deleted a conserved dual-tyrosine endosomal sorting motif, resulting in higher cell surface expression and more potent inhibition of Friend retrovirus release compared to C57BL/6 (B6) Tetherin in vitro. Analysis of (B6Γ—NZW)F1 hybrid mice revealed that increased Tetherin cell surface expression in NZW mice is a recessive trait in vivo. Using a classical genetic backcrossing approach, NZW Tetherin expression strongly correlated with decreased Friend retrovirus replication and pathogenesis. However, the protective effect of NZW Tetherin was not observed in the context of B6 Apobec3/Rfv3 resistance. These findings identify the first functional Tetherin polymorphism within a mammalian host, demonstrate that Tetherin cell surface expression is a key parameter for retroviral restriction, and suggest the existence of a restriction factor hierarchy to counteract pathogenic retrovirus infections in vivo

    Portable wireless electrocorticography system with a fexible microelectrodes array for epilepsy treatment

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    In this paper, we present a portable wireless electrocorticography (ECoG) system. It uses a high resolution 32-channel fexible ECoG electrodes array to collect electrical signals of brain activities and to stimulate the lesions. Electronic circuits are designed for signal acquisition, processing and transmission using Bluetooth Low Energy 4 (LTE4) for wireless communication with cell phone. In-vivo experiments on a rat show that the fexible ECoG system can accurately record electrical signals of brain activities and transmit them to cell phone with a maximal sampling rate of 30 ksampling/s per channel. It demonstrates that the epilepsy lesions can be detected, located and treated through the ECoG system. The wireless ECoG system has low energy consumption and high brain spatial resolution, thus has great prospects for future application

    Differential virus restriction patterns of rhesus macaque and human APOBEC3A: Implications for lentivirus evolution

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    AbstractThe human apolipoprotein B mRNA editing enzyme catalytic peptide-like 3 (APOBEC3; A3) family of proteins (A3A-H) are known to restrict various retroviruses and retroelements, but the full complement of rhesus macaque A3 proteins remains unclear. We report the isolation and characterization of the hA3A homologue from rhesus macaques (rhA3A) and show that the rhesus macaque and human A3 genes are orthologous. RhA3A is expressed at high levels in activated CD4+ T cells, is widely expressed in macaque tissues, and is degraded in the presence of the human immunodeficiency virus (HIV-1) and simian–human immunodeficiency virus (SHIV) genomes. Our results indicate that rhA3A is a potent inhibitor of SHIVΞ”vif and to a lesser extent HIV-1Ξ”vif. Unlike hA3A, rhA3A did not inhibit adeno-associated virus 2 (AAV-2) replication and L1 retrotransposition. These data suggest an evolutionary switch in primate A3A virus specificity and provide the first evidence that a primate A3A can inhibit lentivirus replication

    Early Cretaceous high-Ti and low-Ti mafic magmatism in Southeastern Tibet: Insights into magmatic evolution of the Comei Large Igneous Province

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    The Dala diabase intrusion, at the southeastern margin of the Yardoi gneiss dome, is located within the outcrop area of the ~ 132 Ma Comei Large Igneous Province (LIP), the result of initial activity of the Kerguelen plume. We present new zircon U-Pb geochronology results to show that the Dala diabase was emplaced at ~ 132 Ma and geochemical data (whole-rock element and Sr-Nd isotope ratios, zircon Hf isotopes and Fe-Ti oxide mineral chemistry) to confirm that the Dala diabase intrusion is part of the Comei LIP. The Dala diabase can be divided into a high-Mg/low-Ti series and a low-Mg/high-Ti series. The high-Mg/low-Ti series represents more primitive mafic magma compositions that we demonstrate are parental to the low-Mg/high-Ti series. Fractionation of olivine and clinopyroxene, followed by plagioclase within the low-Mg series, lead to systematic changes in concentrations of mantle compatible elements (Cr, Co, Ni, and V), REEs, HFSEs, and major elements such as Ti and P. Some Dala samples from the low-Mg/high-Ti series contain large ilmenite clusters and show extreme enrichment of Ti with elevated Ti/Y ratios, likely due to settling and accumulation of ilmenite during the magma chamber evolution. However, most samples from throughout the Comei LIP follow the Ti-evolution trend of the typical liquid line of descent (LLD) of primary OIB compositions, showing strong evidence of control of Ti contents by differentiation processes. In many other localities, however, primitive magmas are absent and observed Ti contents of evolved magmas cannot be quantitatively related to source processes. Careful examination of the petrogenetic relationship between co-existing low-Ti and high-Ti mafic rocks is essential to using observed rock chemistry to infer source composition, location, and degree of melting

    Component Thermodynamical Selection Based Gene Expression Programming for Function Finding

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    Gene expression programming (GEP), improved genetic programming (GP), has become a popular tool for data mining. However, like other evolutionary algorithms, it tends to suffer from premature convergence and slow convergence rate when solving complex problems. In this paper, we propose an enhanced GEP algorithm, called CTSGEP, which is inspired by the principle of minimal free energy in thermodynamics. In CTSGEP, it employs a component thermodynamical selection (CTS) operator to quantitatively keep a balance between the selective pressure and the population diversity during the evolution process. Experiments are conducted on several benchmark datasets from the UCI machine learning repository. The results show that the performance of CTSGEP is better than the conventional GEP and some GEP variations
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