Heat stress negatively affects reproduction in cattle by disrupting the normal function of ovarian granulosa cells (GCs), ultimately leading to oxidative damage and cell death via apoptosis. Heme oxygenase-1(HO-1) is a member of the heat shock protein family, which are associated with cellular antioxidant defenses and anti-apoptotic functions. Recent studies demonstrated that HO-1 is upregulated in heat-stressed cells. In the present study, we investigated the expression of HO-1 in bovine GCs transiently exposed to heat stress and characterized the expression and activity of key oxidative stress enzymes and molecules. We show that heat stress induced oxidative stress and apoptosis, and enhanced Nrf2 and HO-1 expression in primary GC cultures. Knocking down HO-1 expression using siRNA exacerbated both oxidative stress and apoptosis, whereas pre-treating GCs with hemin, which induces HO-1 expression, partially prevented these effects. These findings demonstrate that HO-1 attenuates heat stress-induced apoptosis in bovine GCs by decreasing production of reactive oxygen species and activating the antioxidant response.
We study the hadron-quark phase transition in the interior of neutron stars. The relativistic mean field (RMF) theory is adopted to describe the hadronic matter phase, while the Nambu-Jona-Lasinio (NJL) model is used for the quark matter phase. The influence of the hadronic equation of state on the phase transition and neutron star properties are investigated. We find that a neutron star possesses a large population of hyperons, but it is not dense enough to possess a pure quark core. Whether the mixed phase of hadronic and quark matter exist in the core of neutron stars depends on the RMF parameters used.
We study the properties of double-Λ hypernuclei in the relativistic mean-field theory, which has been successfully used for the description of stable and unstable nuclei. With the meson-hyperon couplings determined by the experimental binding energies of single-Λ hypernuclei, we present a self-consistent calculation of double-Λ hypernuclei in the relativistic mean-field theory, and discuss the influence of hyperons on the nuclear core. The contribution of two mesons with dominant strange quark components (scalar σ* and vector φ) to the ΛΛ binding energy of double-Λ hypernuclei is examined.
Mastitis has severely affected the cattle industry worldwide and has resulted in decreased dairy production and cattle reproduction. Although prevention and treatment methods have been implemented for decades, cattle mastitis is still an intractable disease. Sirtuin 7 (SIRT7) is an NAD+-dependent deacetylase that is involved in various biological processes, including ribosomal RNA synthesis and protein synthesis, DNA damage response, metabolism, and tumorigenesis. However, whether SIRT7 participates in inflammation remains unknown. Our results revealed that SIRT7 is downregulated in tissue samples from mastitic cattle. Therefore, we isolated dairy cow mammary epithelial cells (DCMECs) from breast tissues and developed an in vitro model of lipopolysaccharide- (LPS-) induced inflammation to examine SIRT7 function and its potential role in inflammation. We showed that SIRT7 was significantly downregulated in LPS-treated DCMECs. SIRT7 knockdown significantly increased the LPS-stimulated production of inflammatory mediators, like reactive oxygen and nitric oxide, and upregulated TAB1 and TLR4. In addition, SIRT7 knockdown significantly increased the phosphorylation of TAK1 and NF-κBp65 in LPS-treated DCMECs. Moreover, SIRT7 knockdown promoted the translocation of NF-κBp-p65 to the cell nucleus and then increased the secretion of inflammatory cytokines (IL-1β and IL-6). In contrast, SIRT7 overexpression had the opposite effects when compared to SIRT7 knockdown in LPS-treated DCMECs. In addition, SIRT7 overexpression attenuated LPS-induced DCMEC apoptosis. Taken together, our results indicate that SIRT7 can suppress LPS-induced inflammation and apoptosis via the NF-κB signaling pathway. Therefore, SIRT7 may be considered as a potential pharmacological target for clinical mastitis therapy.
A bstract : The extreme toxicity of organophosphorous‐based compounds has been known since the late 1930s. Starting in the mid‐1940s, many nations throughout the world have been producing large quantities of organophosphorous (OP) nerve agents. Huge stockpiles of nerve agents have since developed. There are reportedly more than 200,000 tons of nerve agents in existence worldwide. There is an obvious need for protective clothing capable of guarding an individual from exposure to OP chemical weapons. Also, chemical processes that can effectively demilitarize and detoxify stored nerve agents are in great demand. The new and widely publicized Chemical Weapons Treaty requires such processes to soon be in place throughout the world. Biotechnology may provide the tools necessary to make such processes not only possible, but quite efficient in reducing the nerve agent dilemma. The following paper discusses some of the history in developing enzyme technology against nerve agents. Our laboratory has interest in enhancing the productivity and potential utility of these systems in both demilitarization and decontamination applications. Freeze‐dried nerve agent‐hydrolyzing enzyme preparations have been shown to be effective in decontaminating gaseous nerve agents. The direct incorporation of nerve agent‐hydrolyzing enzymes within cross‐linked polyurethane foam matrices during polymer synthesis has been shown to dramatically enhance the productivity of two different enzyme systems. The future goal of such work lies in building a bridge between the clinical application of nerve agent‐hydrolyzing enzymes and practical processing techniques that may take advantage of the initial results already achieved in the laboratory.
Abstract Baker's yeast cells entrapped in alginate beads are shown to catalyze reactions in organic solvents when a cofactor regeneration scheme is implemented. This study focused on the reduction of acetophenone to 1‐phenylethanol, using baker's yeast as well as a cosubstrate to regenerate the cofactor. The product is a chiral alcohol, and it was desired to maintain a high enantiomeric excess. The effects of parameters such as the addition of a cosubstrate, water content, fermentation time, buffer pH, and bead diameter have been investigated. Such a general process may be quite useful when single enantiomers are needed, as well as for the production of other chemicals.
Abstract Dehydrogenation plays a very important role in both nature and human civilization. In chemical industry, dehydrogenations are used to produce propene, butene, butadiene, isobutene, and isopropene from the corresponding alkanes. In living organisms (both animals and plants), respiration is actually a process of oxidation wherein some steps involve dehydrogenation. Almost all dehydrogenation reactions require a catalyst. Catalysts for dehydrogenation can be classified into two main categories: conventional catalysts (including inorganic and organic) and enzymes. This article focuses on the application of biological catalysts in dehydrogenation and oxidation reactions occurring in nature. Biological dehydrogenation is illustrated from two aspects: chemistry of biocatalytic dehydrogenation and biocatalysts of dehydrogenation. Biological dehydrogenation reactions usually occur at very mild conditions and have very high selectivity. The catalysts for these processes are usually enzymes (or cells producing these enzymes). Enzymes having dehydrogenation capacities are usually dehydrogenases, oxidases, etc., and most of them need a coenzyme or a cofactor to work with them.
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