Immunoprecipitation of a cytoplasmic precursor of rat-liver cytochrome oxidase.

A simple method for the isolation of rat liver cells is described. The cells are shown, by an isotope dilution method, to maintain a constant rate of protein synthesis for 8 h of incubation. Antibodies to purified rat liver cytochrome oxidase were raised in rabbits and used to investigate the labeling of cytochrome oxidase in isolated rat liver cells and in vivo. The data demonstrate the occurrence of a precursor of the subunits of cytochrome oxidase that are synthesized in the cytoplasm. 1. Dodecylsulfate gel electrophoresis of the immunoprecipitates from isolated rat liver cells that had been labeled with [35S]methionine for 1 h showed a single radioactive peak with a molecular weight of 50000. 2. Judged by the effects of cycloheximide and chloramphenicol the labeled protein is synthesized on cytoplasmic ribosomes. 3. After labeling for 1 h in vivo with [3H]leucine the labeled protein appears to be exclusively associated with the hepatic microsomal fraction. 4. Ouchterlony double-diffusion analysis demonstrated immunological relationship between the precipitates from microsomes and cytochrome oxidase. In addition to the precipitates derived from mitochondria and microsomes immunoprecipitates were also obtained from the cytosol in comparable amounts; these again were immunologically related. The occurrence of large amounts of precursor(s) (or degradation products) of cytochrome oxidase in rat liver fractions is interpreted in terms of a regulatory pool for amino acid homeostasis in the organism.     

Characterization of four members of a multigene family encoding outer membrane proteins of Helicobacter pylori and their potential for vaccination

In search of protective antigens which can be used in a vaccine to prevent Helicobacter pylori infection, we report on the identification of four genes, hopV, hopW, hopX and hopY, and the characterization of the corresponding proteins which belong to the H. pylori outer membrane protein (Hop) family containing 32 homologous members, some of which were shown to function as porins. Sequence analysis of 16 different H. pylori strains revealed that the proteins HopV, HopW, HopX and HopY are highly conserved. Localization of HopV, HopW, HopX and HopY at the surface of the bacteria was investigated by immunofluorescence. Using a planar lipid bilayer system the proteins HopV and HopX were shown to form pores with single-channel conductances of 1.4 and 3.0 nS, respectively.     

Sensitive liquid chromatography-tandem mass spectrometry method for the determination of clarithromycin in human plasma

A sensitive method for the determination of clarithromycin in plasma is described, using high-performance liquid chromatographic separation with tandem mass spectrometric detection. Samples were prepared using liquid-liquid extraction and separated on a Supelco Discovery C18 column with a mobile phase consisting of acetonitrile, methanol and acetic acid. Detection was performed by a PE SCIEX API 2000 mass spectrometer in the multiple reaction monitoring (MRM) mode (LC-MS-MS) using TurbolonSpray ionization and monitoring the transition of the protonated molecular ion for clarithromycin at m/z 748.5 (M+1) to the predominant product ion of m/z 158.2. The mean recovery of clarithromycin was 87.3%, with a lower limit of quantification of 2.95 ng/ml when using 0.3-ml plasma. This high-throughput method was used to quantify 230 samples per day, and is sufficiently sensitive to be employed in pharmacokinetic studies.     

Cultivation of Mycobacterium bovis BCG in bioreactors

The Mycobacterium bovis BCG vaccine for commercial use is classically produced as surface pellicles by culture on synthetic medium. Under these conditions, reproducibility of the cultures and quality assessment are hampered by slow growth of the bacilli, the formation of bacterial aggregates and a high proportion of dead bacilli after processing and final formulation of the vaccine. Here, we established dispersed cultures of M. bovis BCG in synthetic media in small-scale bioreactors. These cultures allow recording and adjusting of culture parameters and give rise to single bacilli with a high degree of live bacteria. In the murine model, bioreactor-grown M. bovis BCG exhibited slightly stronger replication and persistence than the vaccine produced under the classical conditions. The protective efficacy against challenge with M. tuberculosis was identical for both vaccine preparations.     

The Inhibitory Effects of Anacardic Acid on Hepatitis C Virus Life Cycle

Hepatitis C virus (HCV) is a small positive-sense single-stranded RNA virus that causes severe liver diseases. Current anti-HCV therapies involving direct-acting antivirals have significantly enhanced efficacy in comparison to traditional interferon and ribavirin combination. However, further improvement is needed to eradicate HCV. Anacardic acid (AnA) is a phytochemical compound that can inhibit the activity of various cellular enzymes including histone acetyltransferases (HATs). In this study, we investigated the effects of AnA on different phases of HCV life cycle. Our data showed that AnA can inhibit HCV entry, replication, translation, and virion secretion in a dose-dependent manner with no measurable effects on cell viability. In addition, we showed that two HAT inhibitors and knocking down HAT (PCAF) by RNAi can reduce HCV replication, suggesting a mechanism of AnA’s inhibitory effects on HCV. Elucidation of the AnA-mediated inhibitory mechanism should facilitate the development of new drug candidates for HCV infection.     

Effect of non-native versus native invaders on macrophyte richness: are carp and bullheads ecological proxies?

Hydrobiologia - While it is accepted that invasive species are non-native organisms that become abundant and cause ecological damage in areas where they are introduced, the problem of ‘native...     

Highly pathogenic avian influenza viruses do not inhibit interferon synthesis in infected chickens but can override the interferon-induced antiviral state

From infection studies with cultured chicken cells and experimental mammalian hosts, it is well known that influenza viruses use the nonstructural protein 1 (NS1) to suppress the synthesis of interferon (IFN). However, our current knowledge regarding the in vivo role of virus-encoded NS1 in chickens is much more limited. Here, we report that highly pathogenic avian influenza viruses of subtypes H5N1 and H7N7 lacking fully functional NS1 genes were attenuated in 5-week-old chickens. Surprisingly, in diseased birds infected with NS1 mutants, the IFN levels were not higher than in diseased birds infected with wild-type virus, suggesting that NS1 cannot suppress IFN gene expression in at least one cell population of infected chickens that produces large amounts of the cytokine in vivo. To address the question of why influenza viruses are highly pathogenic in chickens although they strongly activate the innate immune system, we determined whether recombinant chicken alpha interferon (IFN-α) can inhibit the growth of highly pathogenic avian influenza viruses in cultured chicken cells and whether it can ameliorate virus-induced disease in 5-week-old birds. We found that IFN treatment failed to confer substantial protection against challenge with highly pathogenic viruses, although it was effective against viruses with low pathogenic potential. Taken together, our data demonstrate that preventing the synthesis of IFN is not the primary role of the viral NS1 protein during infection of chickens. Our results further suggest that virus-induced IFN does not contribute substantially to resistance of chickens against highly pathogenic influenza viruses.