Phospholipid Composition of Venezuelan Equine Encephalitis Virus

Phospholipid analyses of Venezuelan equine encephalitis virus showed that virus propagated in L-cell monolayers had a higher sphingomyelin content and a lower phosphatidylcholine content than virus grown in chick fibroblast monolayers. Virus of L-cell origin also was found to possess greater thermal stability than virus derived from the chick fibroblast cell.     

Replication and Complementation of Human Adenoviruses and Simian Papovavirus at an Elevated Temperature

The simian papovavirus SV40 replicated as well in simian cells incubated at 41 C as in cells incubated at 37 C, although the latent period was shortened at the elevated temperature. Human adenoviruses differed in their responses to the elevated temperature. Some serotypes, such as 3, 4, 5, 7, 8, 16, and 21, replicated as well, or almost as efficiently, in human cells incubated at 41 C as in cells incubated at 37 C, whereas with other serotypes, such as 1, 2, 6, 12, and 14, maximal yields in cultures incubated at 41 C were much lower than the yields from companion cultures incubated at 37 C. This difference was also detected in simian cells co-infected with SV40 and a human adenovirus; maximal complementation occurred with some serotypes at the elevated temperature but not with other serotypes. The degree of complementation observed in the simian cells at 41 C was directly correlated with the ability of the adenovirus to replicate at 41 C in human cells. Therefore, the capacity of SV40 to serve as a helper virus is not affected by the elevated temperature, showing that the complementation event supplied by the simian virus is heat-stable between 37 and 41 C. Maximal complementation appeared to depend upon a characteristic present in the adenovirus genome.     

Structural analysis of dextrans containing 4-O-α-d-glucosylated α-d-glucopyranosyl residues at the branch points,by use of 13c-nuclear magnetic resonance spectroscopy and gas-liquid chromatography-mass spectrometry

Dextran fractions from NRRL strain Streptococcus sp. B-1526 and the native, structurally homogeneous dextrans from Acetobacter capsulatum B-1225, Leuconostoc mesenteroides B-1307, and L. dextranicum B-1420 were examined by ¹³C-n.m.r. spectroscopy at 90°. Dextran B-1526 fraction I and dextran B-1420 were also examined by g.l.c:-m.s., methylation-structural analysis. All of these dextrans and dextran fractions branch, either primarily or exclusively, through α-d-(1→4)-glucopyranosyl linkages; however, their degrees of branching differ. Several ¹³C-n.m.r. resonances that are diagnostic for 4,6-di-O-substituted α-d-glucopyranosyl residues have been identified. Comparison was made with dextrans from L. mesenteroides B-742 fraction L and Streptobacterium dextranicum B-1254 fraction S[L], for which previously published, methylation-structural analyses had established the presence of 4,6-di-O-substituted α-d-glucopyranosyl residues at the branch points. These fermentation culture, and in a sedimented gum-phase (fraction I). The product from the soluble phase is designated here as fraction S in order to simplify the terminology. Originally⁷, this product was not designated a fraction, because it was, by definition⁸, the main dextran product. The same distinction also applies to the pairs of products from strains B-1380, B-1420, and b-1394 (see ref. 7). The attempts thus made to establish the significance of the phase separation were indeterminant.Methods.— Methods previously described were used for the mythylation⁹ of the dextrans and for structural analysis^6.38 by combined g.l.c-electron-impact mass spectrometry of the aldononitriles. For each permethylation, three successive Hakomori³⁹ methylations were employed on an initial, 40-mg sample, with ～80% (final weight) recovery of each permethylated dextran. Successive formolysis and acetic acid hydrolysis were employed, and, after each step, the resulting solutions were clear, colorless, and free from suspended material. All mass spectra were recorded with a Hewlett-Packard 5980A GC/MS integrated g.l.c.-m.s.-computer system. The g.l.c. peak-integrals reported in Table II were obtained with a Barber-Coleman Series 5000 g.l.c. instrument equipped with hydrogen-flame detectors. On-column injection with glass columns (2mmi.d. x 1.23m) was employed for all chromatograhy.The ¹³C-n.m.r. conditions and the methods for the preparation of dextran samples have been described⁴. In general, a Varian XL-100-15 spectrometer equipped with a Nicolet TT-100 system was employed in the Fourier-transform mode. The dextran samples, ～0.3g/4 mL of deuterium oxide, were maintained at 90°. Chemical shifts are expressed in p.p.m. relative to external tetramethylsilane, but were actually calculated by reference to the solvent lock-signal. The convolution-difference resolution-enhancement (c.d.r.e.) technique has been described⁴⁰.     

Donut-shaped “miniparticles” in nuclei of human and rat cells

Donut-shaped “miniparticles” were extracted from nuclei of various types of human and rat cells. Electron-microscopic investigations showed these particles were predominantly in sucrose density gradient fractions that had an approximate sedimentation coefficient of 21S. These particles were 113±8_A^o in diameter and had an electron dense center of 29±6_A^o. They appeared to be composed of 8 subunits. Quantitative analysis of the number of these particles by electron-micrographic field counting showed nuclei of tumor samples had a larger amount of the particles than the cytosol. However, normal cell cytosol had a larger number of particles than the nuclei. A group of proteins in the 25, 000–33, 000 molecular weight range was shown to be the main protein component by two dimensional gel electrophoresis.     

Hemagglutination Inhibition of Passively Sensitized Red Blood Cells

It has been shown that sheep red blood cells sensitized with the polysaccharides of Haemophilus influenzae type B and pneumococcal types I, III, IV, VII, VIII, XII, and XIV respond readily in hemagglutination-inhibition testing and exhibit antigen inhibition at levels of 0.09 to 4.0 ng.     

Systematic implications of sesquiterpene lactones in the subtribe melampodiinae

Within the tribe Heliantheae of the Asteraceae, the genetic boundaries of the subtribe Melampodinae have recently been drastically revised by Stuessy. The number of genera within the subtribe has been reduced and new generic groupings have been established. The present study correlates the distribution of sesquiterpene lactones found in these genera with the newly revised subtribal boundaries. The genera Acanthospermum, Melampodium, Polymnia and Sigesbeckia produce predominantly melampolide-type sequiterpene lactones. Limited chemical data support Stuessy's removal of the genera Desmanthodium, Clibadium and Ichthyothere from the subtribe Melampodiinae. The occurrence of melampolide-type sesquiterpene lactones in members of the genera Tetragonotheca (Helianthinae) and Enhydra (Ecliptinae) indicate a possible position of these genera in the Melampodiinae.