Effects of the S-adenosylhomocysteine hydrolase inhibitors 3-deazaadenosine and 3-deazaaristeromycin on RNA methylation and synthesis

The effects of 3-deazaaristeromycin and 3-deazaadenosine on RNA methylation and synthesis were examined in the mouse macrophage cell line, RAW264. S-Adenosylhomocysteine accumulated in cells incubated with 3-deazaaristeromycin while S-3-deazaadenosylhomocysteine was the major product in cells incubated with 3-deazaadenosine and homocysteine thiolactone. RNA methylation was inhibited to a similar extent by the accumulation of either S-adenosylhomocysteine or S-3-deazaadenosylhomocysteine, with S-adenosylhomocysteine being a slightly better inhibitor. In mRNA, the synthesis of N6-methyladenosine and N6-methyl-2'-O-methyladenosine were inhibited to the greatest extent, while the synthesis of 7-methylguanosine and 2'-O-methyl nucleosides were inhibited to a lesser extent. Incubation of cells with 100 microM 3-deazaaristeromycin or with 10 microM 3-deazaadenosine and 50 microM homocysteine thiolactone produced little inhibition of mRNA synthesis, even though mRNA methylation was inhibited. In contrast, mRNA synthesis was greatly inhibited by treatment of cells with 100 microM 3-deazaadenosine and the inhibition of synthesis was not correlated with an inhibition of methylation.     

Potential of Agrotis ipsilon nucleopolyhedrovirus for suppression of the black cutworm (Lepidoptera: Noctuidae) and effect of an optical brightener on virus efficacy.

Studies were performed in the laboratory, greenhouse and field to assess the potential of Agrotis ipsilon multicapsid nucleopolyhedrovirus (AgipMNPV) and a viral enhancing agent, M2R, for suppression of Agrotis ipsilon (Hufnagel). In laboratory droplet feeding bioassays, AgipMNPV was shown to be highly active against third-instar A. ipsilon. The optical brightener M2R significantly reduced LD50 estimates by approximately 160-fold, but had no direct effect on survival time estimates. In greenhouse trials, spray and bait formulations of AgipMNPV significantly reduced feeding damage to corn seedlings caused by third-instar A. ipsilon. In two sets of replicated field trials, bait formulations of AgipMNPV significantly reduced feeding damage to corn seedlings by third-instar A. ipsilon. However, there were no beneficial effects attributable to the inclusion of M2R in AgipMNPV formulations under greenhouse or field conditions. It seems likely that in an appropriately designed pest management program AgipMNPV could be used to suppress field populations of early and mid-instar A. ipsilon.     

Pectolytic clostridia isolated from sugar beet pulp silages in Italy

Twenty-eight strains of pectolytic clostridia were isolated from sugar beet pulp silages. Seventeen non-pigmented strains were presumed to be Clostridium acetobutylicum ; the remaining 11 pigmented strains were similar to Cl. felsineum. The addition of molasses to sugar beet pulps favoured the growth of other bacteria, particularly lactic acid organisms, whereas pectolytic clostridia were only occasionally found. The pectolytic clostridia promoted the structure loss of simulated silages. The use of molasses in sugar beet pulp ensiling was suggested to prevent texture loss of the ensiled mass.     

Ligand-induced association of rat lymphocyte membrane proteins with the detergent-insoluble lymphocyte cytoskeletal matrix

There are two classes of membrane protein capping on the basis of ligand requirements. Surface immunoglobulin (Slg), the prototype of the first class, requires a single ligand for cap induction. RT1 (rat histocompatibility proteins) requires two antibodies for cap induction. The lateral mobility of Slg is relatively restricted compared with RT1. These differences may be due to differential interaction with the cytoskeleton. After ligand binding 71% of Slg becomes detergent insoluble and is associated with the lymphocyte cytoskeletal matrix. The insolubilization occurs at 4 degrees C and is not inhibited by sodium azide or cytoskeleton-active drugs. The insolubilized ligand-receptor complex can be solubilized by a cytoskeleton destabilizing buffer. In contrast, only 20% of RT1 becomes associated with the lymphocytic cytoskeleton after ligand binding. The ligand-induced receptor-cytoskeleton interaction influences capping behavior and may play a role in cell activation.     

Measurement of cerebral blood flow by transcranial Doppler ultrasonography in children presenting with autistic behavior. Preliminary results

Transcranial Doppler ultrasonographic recordings of the middle cerebral arteries were performed on eight children with autistic behavior compared to eight controls. Blood flow measurements were assessed at rest and during auditory and visual stimulations. The main result was obtained during the auditory stimulations and concerned the left artery blood flow which is lower in autistics than in controls in these conditions (p less than .02). This result confirms the possibility of a left hemisphere dysfunctioning in autistics and may be related to clinical features as language disabilities and paradoxical reactivity to auditory stimuli.     

Differential induction of activation markers in macrophage cell lines by interferon-gamma

Macrophage cell lines were used in these studies as a model system to dissect the biochemical and functional mosaic of the macrophage activation process. In particular, the requirements for the induction of tumoricidal and bactericidal activity in the RAW 264.7 and WEHI-3 cell lines by interferon-gamma (IFN-gamma) and bacterial lipopolysaccharide (LPS) were determined. Changes in expression of a series of macrophage markers traditionally associated with macrophage activation were monitored during stimulation of the cells in order to determine whether a detectable pattern of activation-associated changes is associated with the development of a particular functional activity. These markers included changes in the cell surface expression of major histocompatibility complex-encoded Class I and Class II antigens and antigens in the Mac-1/LFA-1 family, alterations in the levels of membrane enzymes (5' nucleotidase and alkaline phosphodiesterase), and production of secretory products including hydrogen peroxide and the monokines interleukin-1, interferons-alpha/beta, and tumor necrosis factor-alpha. Our results demonstrate that a given homogeneous macrophage population expresses a distinct subset of functional activities in response to single, defined activating signals such as IFN-gamma and LPS. The display of a variety of macrophage surface antigens, enzymes, and secreted products is activated simultaneously by such treatment; however, the particular pattern of such activation-associated markers cannot reproducibly be used to predict the ability of an activated cell to perform a particular function. The results also suggest that macrophage cell lines expressing differential response patterns following IFN-gamma stimulation provide a valuable system for dissection of the molecular and cell biology of macrophage activation.