Protein Kinase PKR Mediates the Apoptosis Induction and Growth Restriction Phenotypes of C Protein-Deficient Measles Virus

The measles virus (MV) accessory proteins V and C play important roles in MV replication and pathogenesis. Infection with recombinant MV lacking either V or C causes more cell death than infection with the parental vaccine-equivalent virus (MVvac), and C-deficient virus grows poorly relative to the parental virus. Here, we show that a major effector of the C phenotype is the RNA-dependent protein kinase PKR. Using human HeLa cells stably deficient in PKR as a result of RNA interference-mediated knockdown (PKR^kd cells), we demonstrated that a reduction in PKR partially rescued the growth defect of C knockout (C^ko) virus but had no effect on the growth of either wild-type (WT) or V knockout (V^ko) virus. Increased growth of the C^ko virus in PKR^kd cells correlated with increased viral protein expression, while defective growth and decreased protein expression in PKR-sufficient cells correlated with increased phosphorylation of PKR and the α subunit of eukaryotic initiation factor 2. Furthermore, infection with WT, V^ko, or especially C^ko virus caused significantly less apoptosis in PKR^kd cells than in PKR-sufficient cells. Although apoptosis induced by C^ko virus infection in PKR-sufficient cells was blocked by a caspase antagonist, the growth of C^ko virus was not restored to the WT level by treatment with this pharmacologic inhibitor. Taken together, these results indicate that PKR plays an important antiviral role during MV infection but that the virus growth restriction by PKR is not dependent upon the induction of apoptosis. Furthermore, the results establish that a principal function of the MV C protein is to antagonize the proapoptotic and antiviral activities of PKR.     

Studies on the frequency and associations of equine leucocyte antigens in sarcoid and summer dermatitis

The equine leucocyte antigen (ELA) types and the clinical diagnosis for equine sarcoid and summer dermatitis were evaluated in 2026 horses representing five breeds. Data were analysed in unrelated animals and in family material. In the case of equine sarcoid, a strong association was observed between the ELA class II DW13 antigen and its effect on Swiss (cP < 0·001), French (cP < 0·0001) and Irish (cP < 0·01) Warmblood horses. The class I antigen A3 occurred more frequently in sarcoid-affected French horses (cP < 0·001). These results confirm our earlier findings (Gerber et al. 1988). Among Freiberger horses, which lack the ELA DW13 and A3 specificities, a breed-specific class I antigen, ABe108, displayed an increased frequency (cP < 0·05) in the affected group. Among Arabian horses, a tendency for increased frequency of the A1 antigen was observed in the affected animals, but the number of affected horses is too small for statistical significance. The Mendelian segregation in diseased half-siblings by ELA DW13 heterozygous stallions showed a strong association (P < 0·0001) between the inherited DW13 antigen and susceptibility to the sarcoid effect. In the case of summer dermatitis, previously published data (Marti et al. 1992) have been extended. The ELA types in four multiple-case families, founded by the same stallion, were analysed for an association with the effect of sarcoid. Eight out of nine ELA-typed affected offspring inherited the paternal haplotype A15, DW23 in contrast to nonaffected offspring where three out of 12 displayed these antigens (P < 0·005). Moreover, the ELA haplotypes of 11 out of 12 informative affected half-siblings sired by another stallion inherited the paternal haplotype A3, W12, DW23 (P < 0·05). Our findings demonstrate statistically significant associations between certain ELA antigens and two equine diseases. It is still unknown if the major histocompatibility complex (MHC) molecules themselves or another linked gene(s) play a role in the pathogenesis of these conditions.     

DNA sequence analysis of serologically detected ELA class II haplotypes at the equine DQP locus

The genetic diversity at the ELA DQβ locus was investigated using polymerase chain reaction and DNA sequencing. Based upon serological methods 16 class II homozygous animals were selected and their genomic DNA was used. A DQβ gene from an equine cDNA library was also sequenced. Our methology and the similarity between the genomic and the cDNA sequences suggest that the studied locus is expressed on equine lymphocytes. In the predicted amino acid sequence the most extensive variation is located at residues 56–60. The pattern of these five amino acids is strongly correlated to the serological ELA class II specificities (W13, W22, W23, Be200). The alleles corresponding to the W23 specificity are the most divergent among the equine DQβ alleles and also from other mammalian DQβ sequences.     

Accumulation of the labdane diterpene Marrubiin in glandular trichome cells along the ontogeny of Marrubium vulgare plants

The content of the diterpene Marrubiin was assessed by GC-FID in leaves of Marrubium vulgare plants along their ontogeny. Maximum accumulation occurred just before flowering time and in fully expanded leaves. After feeding the plants with radio labeled [³H]-geranyl geranyl diphosphate, up to 70% of the radioactivity was recovered in HPLC-Rt coincidental with authentic Marrubiin, which was also characterized by GC-EIMS, thus confirming that the biosynthesis of Marrubiin proceeds through the 1-deoxy-D-xylulose-5-phosphate pathway. The major accumulation of radioactivity occurred in glandular trichome cells, and the product remained stable throughout.     

Improved Histology for the Chick-Quail Chimera

A simple modification of nuclear staining after acid hydrolysis has been made which provides easy identification of quail nuclear markings in a chick-quail chimera. This method also improves the histologic detail normally seen with hematoxylin and eosin when compared to the more commonly used Feulgen reaction. Embryonic tissues can be fixed in Zenker's or Helly's solution and the sections obtained are hydrolyzed in acid (3.5 N HCl at 37 C for 40-50 min). After acid hydrolysis the sections are stained with hematoxylin and eosin rather than Schiff reagent and fast green. The interphase nuclei of chick cells show homogeneous or mottled purplish blue staining, while quail nuclei contain a dark blue spot. This staining corresponds to the reddish purple staining of the quail's heterochromatin seen adjacent to the nucleolus in the standard Feulgen stain. This new technique facilitates identification of quail cell types in the chick host and provides superior histology of the chick tissues by demonstrating cytoplasmic detail.     

<Superscript>15</Superscript>N natural abundance of fossil peat reflects the influence of animal-derived nitrogen on vegetation

'¹⁵N signatures of fossil peat were used to interpret past ecosystem processes on tectonically active subantarctic Macquarie Island. By comparing past vegetation reconstructed from the fossil record with present-day vegetation analogues, our evidence strongly suggests that changes in the '¹⁵N signatures of fossil peat at this location reflect mainly past changes in the proportion of plant nitrogen derived from animal sources. Associated with uplift above sea level over the past 8,500 years, fossil records in two peat deposits on the island chronicle a change from coastal vegetation with fur and elephant seal disturbance to the existing inland herbfield. Coupled with this change are synchronous changes in the '¹⁵N signatures of peat layers. At two sites ¹⁵N-enriched peat '¹⁵N signatures of up to +17‰ were associated with a high abundance of pollen of the nitrophile Callitriche antarctica (Callitrichaceae). At one site fossil seal hair was also associated with enriched peat '¹⁵N. Less ¹⁵N enriched '¹⁵N signatures (e.g. -1.9‰ to +3.9‰) were measured in peat layers which lacked animal associated C. antarctica and Acaena spp. Interpretation of a third peat profile indicates continual occupation of a ridge site by burrowing petrels for most of the Holocene. We suggest that ¹⁵N signatures of fossil peat remained relatively stable with time once deposited, providing a significant new tool for interpreting the palaeoecology.     

Deanol Affects Choline Metabolism in Peripheral Tissues of Mice

Abstract: The enzymatic hydrolysis of UDP-galactose in rat and calf brain was studied. The hydrolysis occurs in two steps: The first is the conversion of UDP-galactose to galactose-1-phosphate catalyzed by nucleotide pyrophosphatase (EC 3.6.1.9), and the second is the conversion of the latter to free galactose by alkaline phosphatase (EC 3.1.3.1). The overall conversion has a pH optimum of 9.0, but there is considerable activity at pH 7.4, which is the optimum for UDP-galactose:ceramide galactosyltransferase in the synthesis of cerebrosides. Preparations from cytosol from calf brain cerebellum or stem that were enriched in UDP-galactose hydrolytic activity inhibit cerebroside synthesis under conditions optimal for the synthesis. Microsome-rich and nuclear debris fractions contain the highest apparent specific activity among the subcellular fractions studied. Hydrolysis of UDP-galactose occurs in all areas of brain, brainstem having the highest activity. The apparent specific activity in jimpy mouse brain homogenate is nearly twice as high as in the control brain homogenate.