Seed transmission of turnip yellow mosaic virus in winter turnip and winter oilseed rapes

This is the first record of seed transmission of turnip yellow mosaic virus (TYMV) in oilseed and turnip rapes. The seed transmission of TYMV in a naturally infected winter turnip rape (Brassica napus var. silvestris) cultivar Perko PVH was investigated. By ELISA 1.6%, 3.2% and 8.3% seed transmission of the virus was found in seed of plants from three localities. The proportion of infected seeds produced by artificially infected plants of winter oilseed rape (Brassica napus ssp. oleifera) and winter turnip rape cultivars was determined. The virus transmission rate, expressed as the proportion of virus-infected plants which germinated from the seed was for the oilseed rape cvs Jet Neuf 0.1%, Solida 0.4%, Silesia 0.8%, Darmor 1.2%, SL-507 0.2%, SL-509 0.0% and for the winter turnip rape cv. Perko 1.5%. ELISA cannot be used in direct tests on bulk seed lots to estimate proportion of infected seed, but must be used on germinated seedlings.     

Spatial proximity and sequence localization of the reactive sulfhydryls of porphobilinogen synthase.

The zinc metalloenzyme porphobilinogen synthase (PBGS) contains several functionally important, but previously unidentified, reactive sulfhydryl groups. The enzyme has been modified with the reversible sulfhydryl-specific nitroxide spin label derivative of methyl methanethiosulfonate (MMTS), (1-oxyl-2,2,5,5-tetramethyl-delta 3-pyrroline-3-methyl)methanethiosulfonate (SL-MMTS) (Berliner, L. J., Grunwald, J., Hankovszky, H. O., & Hideg, K., 1982, Anal. Biochem. 119, 450-455). EPR spectra show that SL-MMTS labels three groups per PBGS subunit (24 per octamer), as does MMTS. EPR signals reflecting nitroxides of different mobilities are observed. Two of the three modified cysteines have been identified as Cys-119 and Cys-223 by sequencing peptides produced by an Asp-N protease digest of the modified protein. Because MMTS-reactive thiols have been implicated as ligands to the required Zn(II), EPR spectroscopy has been used to determine the spatial proximity of the modified cysteine residues. A forbidden (delta m = 2) EPR transition is observed indicating a through-space dipolar interaction between at least two of the nitroxides. The relative intensity of the forbidden and allowed transitions show that at least two of the unpaired electrons are within at most 7.6 A of each other. SL-MMTS-modified PBGS loses all Zn(II) and cannot catalyze product formation. The modified enzyme retains the ability to bind one of the two substrates at each active site. Binding of this substrate has no influence on the EPR spectral properties of the spin-labeled enzyme, or on the rate of release of the nitroxides when 2-mercaptoethanol is added.(ABSTRACT TRUNCATED AT 250 WORDS)     

N-glycans of recombinant human interferon-gamma change during batch culture of chinese hamster ovary cells

A recombinant Chinese hamster ovary (CHO) cell line making human interfron-gamma (IFN-gamma) was grown in 12-L stirred tank fermentors in three batch fermentations under conditions of constant temperature, pH, and dissolved oxygen tension. In addition to cell growth, metabolite, and productivity data, a detailed analysis of the carbohydrate structures attached to each glycosylation site of IFN-gamma was achieved using matrix-assisted laser desorption mass spectrometry (MALDI-MS) in combination with exoglycosidase array sequencing. Complex biantennary oligosaccharides (particularly Gal(2)GlcNAc(4)Man(3) which was core alephl-6 fucosylated at Asn(25) but not at Asng(97)) were most prevalent at both glycosylation sites. However, considerable microheterogeneity arising from the presence of triantennary and truncated glycan structures was also observed. The proportion of the dominant core glycan structure (Gal(2)GlcNAc(4)Man(3) +/- Fuc(1)) decreased by 15-26% during batch culture, with increases in the proportion of oligomannose and truncated glycans over the same time period. Prolonged culture resulting from an extended lag phase led to further accumulation of oligomannose and truncated structures, reaching up to 52% of total glycans attached to Asng(97) by 240 h of culture. The implications of these glycosylation changes for optimizing the time for harvesting cell cultures, and for the clearance of recombinant therapeutic products in vivo are discussed. (c) 1995 John Wiley & Sons, Inc.     

(CGG) trinucleotide repeat polymorphism in the 5′ region of the HHR6B gene: the human homolog of the yeast DNA repair gene RAD6

The polymerase chain reaction was used to detect polymorphisms in a (CGG) trinucleotide repeat sequence in the 5 region of the human HHR6B DNA repair gene on chromosome 5q23-31     

Effect of concanavalin A on lymphocyte interactions involved in the antibody response to type III pneumococcal polysaccharide I. Comparison of the suppression induced by con A and low dose paralysis.

Concanavalin A (Con A) administered at the time of immunization induces suppression of the in vivo splenic plaque-forming cell (PFC) response to type III pneumococcal polysaccharide (SSS-III). As with low dose paralysis of the PFC response to SSS-III, Con A-induced suppression could not be demonstrated in congenitally athymic (nu/nu) mice and could be eliminated partially by treatment with anti-lymphocyte serum (ALS). The kinetics for Con A-induced suppression paralleled those for low dose paralysis of the antibody response to SSS-III. These findings support the view that Con A-induced suppression is produced in vivo by suppressor T cells and that this form of suppression shares with low dose paralysis a common pathway through which suppression is mediated.     

Aspects of hadrosaurian cranial anatomy

Supraorbital bones in Saurolophus angustirostris are described, and their presence in all hadrosaurs is suggested. Frontal-nasal and premaxillar-nasal fontanellae are distinguished in hadrosaurs; their presence is explained as connected with growth and considered to he responsible for the variability of crest structures. New data indicating the presence of a cartilaginous diverticulum nasi within the circumnarial depression in Saurobphus ongustirostris are presented. A physiological (respiratory and/or thermoregulatory) function of the nasal diverticulum is proposed.     

Selective sensitivity to hydrocortisone of regulatory functions that determine the magnitude of the antibody response to type III pneumococcal polysaccharide.

Previous studies on the basis for the immunosuppressive potential of adrenal corticosteroids have stressed that the effects of these agents on immune functions depend on the animal species being considered, as well as the subpopulations of lymphocytes involved in the expression of immune functions examined. In the present work, we have evaluated the effect of a single dose of hydrocortisone on three different immunoregulatory functions that can influence the magnitude of an antibody response to Type III pneumococcal polysaccharide (SSS-III) in mice; these functions include suppressor, amplifier, and helper activity that are dependent upon the presence of distinct subpopulations of thymus-derived (T) cells. The results obtained show that a single injection of a relatively large dose of hydrocortisone, when given at the time of priming with carrier, eliminated all evidence of carrier-specific helper T cell activity; hydrocortisone was also found to eliminate a significant amount of helper T cell activity when given after such activity had been generated. But, under the same experimental conditions, suppressor and amplifier T cell activities were unaffected, even in this steroid-sensitive species. Such selective sensitivity may account for some of the immunosuppressive potency of steroids.     

EFFECTS OF NITRATE CONCENTRATION ON THE GROWTH AND PHYSIOLOGY OF LAMINARIA SACCHARINA (PHAEOPHYTA) IN CULTURE1,2

Laminaria saccharina Lamour. sporophytes were grown in enriched and synthetic media through a range of nitrate concentrations, There was an approximately linear relationship between growth and nutrient concentration up to 10 μ substrate concentration. The half-saturation constant (K_{2) was ca. 1.4 μ NO3-. The internal levels of NO3- increased at substrate concentrations above 10 μM b>3- and reached levels several thousand times higher than the surrounding medium. Thus there is evidence for luxury consumption of NOsb>3}^-. The chlorophyll content and photosynthetic capacities of plants also increased with increasing external NO₃^- The ecological implications of this work are considered.     

Infectious primate type C virus proviral DNA in productively infected cells.

Cell lines competent to infection by DNA from cultures chronically infected by type C viruses of the simian sarcoma virus and baboon endogenous virus groups were identified. Significant differences were observed in the relative susceptibility of some cell lines to infection by a given proviral DNA. Practical applications of transfection techniques for the separation of viruses from dually infected cultures and to free virus stocks from mycoplasmal contamination are described.     

Apigenin and amentoflavone glycosides in the psilotaceae and their phylogenetic significance

Documentation of amentoflavone O-glucosides as the predominant flavonoid glycosides in both genera of the Psilotaceae clearly distinguishes this family from all other families of vascular plants. Psilotum and Tmesipteris also possess apigenin C- and O-glycosides as common flavonoid types. Apigenin 7-O-rhamnoglucoside occurs in both genera and the previously undocumented apigenin 7-O-rhamnoglucoside-4′-O-glucoside, although identified only in Tmesipteris, may also be present in Psilotum. The existence of flavone C-glycosides in both genera may provide a phytochemical relationship between the Psilotaceae and some ferns. The phylogenetic significance of these results is discussed.