Ruminal micro‐organisms do not adapt to increase utilization of poly‐phenol oxidase protected red clover protein and glycerol‐based lipid

BACKGROUND: The enzyme polyphenol oxidase (PPO) reduces the extent of proteolysis and lipolysis within red clover fed to ruminants with subsequent increases in the efficiency of N utilization and the level of beneficial polyunsaturated fatty acids in their products (meat and milk). It has also been reported that red clover feeding alters the rumen microbial population compared to grass feeding. This study investigated whether the observed shifts in the microbial population of the rumen when ruminants are fed red clover silage (RC) as opposed to grass silage (G) represented an adaptation by the micro‐organisms to increase the utilization of PPO‐protected protein and glycerol‐based lipid. RESULTS: The experiment consisted of two periods where ruminally fistulated dairy cows were offered either RC or G for 2 weeks, followed by collection of rumen fluid, which was then used in in vitro incubations to investigate lipolysis and proteolysis over time in plant material derived from red clover plants with either wild type PPO expression (PPO+) or PPO expression reduced to undetectable levels by gene silencing (PPO?). Proteolysis and lipolysis (P < 0.05) were lower after 24 h of incubation in the PPO+ treatment than the PPO? treatment irrespective of rumen fluid. Biohydrogenation of C18 polyunsaturated fatty acids was also lower on the PPO+ treatment than the PPO? treatment, with no effect of rumen fluid. CONCLUSION: These results suggest that microbial changes to red clover feeding did not result in an increased ability of the micro‐organisms in the present study to utilize either PPO‐protected protein or glycerol‐based lipid. Copyright © 2008 Society of Chemical Industry     

Long-term care of an individual with schizophrenia: pharmacologic, psychological, and social factors

Four case reports of mesenchymal neoplasms showing chromosomal abnormalities are presented. In a case of hemangiopericytoma trisomy 2 and centric fusion 19;21 were present. In a mastocytoma a deleted chromosome 35 was seen. A homogeneously staining region (HSR) on chromosome 1 was detected in a histiocytoma. Trisomy 5 and monosomy 31 were observed in a case of granulocytic sarcoma (chloroma). The lack of mutations in exons 1 and 2 of oncogenes N-ras, K-ras, and H-ras and exons 5, 6, 7, and 8 of tumor suppressor gene p53 in these four patients and in a larger series of investigated dogs (25 hemangiopericytomas, 12 mastocytomas, and 8 histiocytomas) is highlighted.     

Immune responses to Ro60 and its peptides in mice. I. The nature of the immunogen and endogenous autoantigen determine the specificities of the induced autoantibodies

Two fatty acid hydroperoxide lyases (HPO lyase I and II) were purified to apparent homogeneity from etiolated hypocotyls of sunflower (Helianthus annuus L.) by a combination of ion-exchange, hydrophobic interaction, and gel filtration chromatography. The two HPO lyases were separated during the hydrophobic interaction chromatography step, with HPO lyase I more hydrophilic than HPO lyase II. The estimated M(r) of both native HPO lyases was determined by gel filtration to be 200,000 and SDS-PAGE in the presence of 100 mM dithiothreitol showed that the enzyme was composed of a single 53 kDa peptide, suggesting that the enzyme exists as a tetramer in vivo. HPO lyase was also abundant in the cotyledons and green leaves. HPO lyases I and II from hypocotyl metabolized 13-hydroperoxylinoleic acid and 13-hydroperoxylinolenic acid to the same extent, but the green leaf enzyme was more than ten-fold more active with 13-hydroperoxylinolenic acid than 13-hydroperoxylinoleic acid. A difference spectrum between CO-bound and CO-unbound dithionite-reduced HPO lyase I showed an absorbance maximum at 452 nm, indicating that it was a cytochrome P450-type enzyme. The activities of HPO lyase I and II were significantly inhibited by nordihydroguaiaretic acid, sulfhydryl reagents, and piperonylbutoxide, which is a cytochrome P450 inhibitor.     

Inhibition of platelet aggregation by S-nitroso-cysteine via cGMP-independent mechanisms: evidence of inhibition of thromboxane A2 synthesis in human blood platelets

S-Nitroso-cysteine (SNC), a putative endothelium-derived relaxing factor, potently inhibited collagen- and arachidonic acid-induced platelet aggregation (IC50=100 nM) and thromboxane A2 (TxA2) synthesis of human blood platelets. ODQ, a selective inhibitor of the soluble guanylyl cyclase, inhibited SNC-induced formation of cGMP but did not reverse inhibition by SNC of collagen- and arachidonic acid-induced platelet aggregation. Combination of ODQ with SQ-29548, a specific platelet TxA2 receptor antagonist, did not modify the antiaggregatory action of SNC. Our study shows that SNC inhibits platelet aggregation by cGMP-independent mechanisms that may involve inhibition of TxA2 synthesis in human platelets.     

DNA-Protein crosslinks induced by nickel compounds in isolated rat renal cortical cells and its antagonism by specific amino acids and magnesium ion

Suspensions of isolated renal cortical cells in modified Krebs-Henseleit buffer (pH 7.4) were incubated with nickel chloride, nickel acetate, nickel sulfate, and nickel subsulfide (0-2 mM) at 37 degreesC for 2 h. A significant increase (63%) in DNA-protein crosslinks was observed at 2 mM nickel sulfate, whereas nickel subsulfide induced a significant increase in such crosslinks beginning at 0.5 mM concentration and a maximum increase of 200% of the control value reached at 2 mM concentration. No significant reduction in viability of renal cortical cells (as measured by trypan blue exclusion) was observed due to these nickel compounds at any concentration used. In the second series of experiments, coincubation of nickel subsulfide (2 mM) with l-histidine (8 or 16 mM), l-cysteine (4 or 8 mM), or l-aspartic acid (8 or 24 mM) significantly reduced the DNA-protein crosslinks induced by 2 mM nickel subsulfide. Similarly Mg2+ (24 mM), but not Ca2+ (24 mM), was able to antagonize nickel subsulfide-induced increase in DNA-protein crosslinks. High extracellular levels of Mg2+ and these amino acids significantly decreased the accumulation of Ni2+ from nickel subsulfide in renal cortical cells. Furthermore, these amino acids at high concentrations significantly inhibited the binding of Ni2+ from nickel subsulfide to deproteinized DNA from renal cortical cells, whereas such inhibition due to Mg2+ was close to significant (0.1 > p > 0.05). In vitro exposures of renal cortical cells to nickel subsulfide (0-2 mM) increased the formation of reactive oxygen species in concentration-dependent manner. Furthermore, coincubation of 2 mM nickel subsulfide with either catalase, dimethylthiourea, mannitol, or vitamin C at 37 degreesC for 2 h resulted in a significant decrease of nickel subsulfide-induced formation of DNA-protein crosslinks, suggesting that nickel subsulfide-induced DNA-protein crosslink formation in isolated rat renal cortical cells is caused by the formation of reactive oxygen species. The potent protective effects of these specific amino acids and Mg2+ against nickel subsulfide-induced DNA-protein crosslink formation in isolated renal cortical cells are due to reduction of cellular uptake of Ni2+ and inhibition of the binding of Ni2+ to deproteinized DNA.     

The Saccharomyces cerevisiae succinate-ubiquinone reductase contains a stoichiometric amount of cytochrome b562

The Saccharomyces cerevisiae succinate-ubiquinone reductase or succinate dehydrogenase (SDH) is a tetramer of non-equivalent subunits encoded by the SDH1, SDH2, SDH3, and SDH4 genes. In most organisms, SDH contains one or two endogenous b-type hemes. However, it is widely believed that the yeast SDH does not contain heme. In this report, we demonstrate the presence of a stoichiometric amount of cytochrome b562 in the yeast SDH. The cytochrome is detected as a peak present in fumarate-oxidized, dithionite-reduced mitochondria. The peak is centered at 562 nm and is present at a heme:covalent FAD molar ratio of 0.92+/-0.11. The cytochrome is not detectable in mitochondria isolated from SDH3 and SDH4 deletion strains. These observations strongly support our conclusion that cytochrome b562 is a component of the yeast SDH.     

Somatic mutations in the kinase domain of the Met/hepatocyte growth factor receptor gene in childhood hepatocellular carcinomas

The MET protooncogene encodes a transmembrane tyrosine kinase identified as the receptor of a polypeptide known as hepatocyte growth factor/scatter factor. We performed PCR-based single-strand conformational polymorphism and sequencing analysis of the tyrosine kinase domain of the MET gene (exon 15-19) in 75 primary liver cancers. Three missense mutations were detected exclusively in 10 childhood hepatocellular carcinomas (HCCs), while no mutations were detected in 16 adult HCCs, 21 cholangiocarcinomas, or 28 hepatoblastomas. The extremely short incubation period from hepatitis B virus infection to the genesis of childhood HCC as compared with the adult HCC suggests that there may be an additional mechanism that accelerates the carcinogenesis of childhood HCC. Our results indicate that mutations of the tyrosine kinase domain of the MET gene may be involved in the acceleration of the carcinogenesis in childhood HCC.     

Phylogenetic re-evaluation of Trametes consors based on mitochondrial small subunit ribosomal DNA sequences

Mitochondrial small subunit ribosomal DNAs of Cerrena unicolor and Trametes consors were sequenced and compared with those of known mushroom taxa. Trametes consors is a species recently transferred from Irpex, and Cerrena is a genus closely related to Trametes. The present phylogenetic tree showed that Cerrena unicolor and Trametes consors clustered together and made an independent lineage from the Trametes group. A new combination, Cerrena consors (Berk.) Ko and Jung, comb nov., is proposed here by transferring Trametes consors into Cerrena based on molecular data along with taxonomic evidence.     

The influence of plant polyphenols on lipolysis and biohydrogenation in dried forages at different phenological stages: in vitro study

BACKGROUND: It is known that forage legumes show a higher transfer efficiency of polyunsaturated fatty acids (PUFA) to ruminant dairy products in comparison with grasses. Legumes are usually characterised by moderate levels of plant secondary metabolites, which can have an effect on lipolysis and biohydrogenation in the rumen. An in vitro study was carried out to compare two species with different plant phenol compositions, Vicia sativa (VS, common vetch, cv. Jose) and Trifolium incarnatum (TI, crimson clover, cv. Viterbo) cut at the vegetative (Veg) and reproductive (Rep) stages, on lipolysis and PUFA biohydrogenation in the rumen. RESULTS: The study showed that forage species and phenological stage affected the levels of bound phenols (BP) and tannic polyphenols (TP). VS was characterised by a higher level of TP than TI at both Veg and Rep stages, whereas BP levels were low in both forages. BP and TP had a negative effect on lipolysis and biohydrogenation, but TP showed a greater negative correlation than BP for both forages. CONCLUSION: These results showed that lipolysis and biohydrogenation of PUFA could be affected by plant phenols, particularly TP. Copyright © 2010 Society of Chemical Industry