IL-1 serves as a secondary signal for IL-9 expression.

IL-9 is produced in vitro by activated CD4+ T cell lines of the Th2 subtype and by naive CD4+ T cells. Here we show that T cell lines stimulated with Con A in the presence of accessory cells (AC) such as irradiated spleen cells or bone marrow-derived macrophages produced substantially more IL-9 than T cells stimulated with Con A alone. These data suggest that AC influence the production of IL-9 through accessory signals that result in an at least 10-fold increase of IL-9 secretion by the respective T cells. Addition of IL-1 to T cells activated by Con A, PHA, or anti-CD3 antibodies revealed that this monokine was responsible for the potentiation of IL-9 production. This finding was confirmed by applying anti-IL-1 antibodies. The production of other lymphokines, namely, IL-3, IL-4, and IL-6, by activated T cells was not or only marginally enhanced in the presence of AC or IL-1, thus indicating that the synthesis of IL-9 is regulated differently from that of other Th2-derived lymphokines. Furthermore, it was demonstrated by Northern blot analysis that IL-1 increases IL-9 expression at the pretranslational level. Because IL-1 alone failed to induce the production of IL-9 by T cells, this monokine acts as a costimulator in combination with a T cell receptor-mediated signal.     

Relationship of Heliothis zea predators, parasitoids and entomopathogens to canopy development in soybean as affected by Heterodera glycines and weeds

The influence of canopy development in soybean on the survival of corn earworm, Heliothis zea (Boddie) (Lepidoptera: Noctuidae), egg and larval stages and population dynamics of arthropod fauna were evaluated in field trials during 1986–88 in eastern North Carolina. Soybean canopy size decreased as soybean cyst nematode, Heterodera glycines Ichinohe (Nematoda: Heteroderidae), initial population densities increased. Plant species composition of the soybean canopy was affected by weed population densities. Mortality of H. zea larvae due to parasitism and infection with entomopathogens was greater in closed canopy and (or) weedy soybeans than in very open and (or) weed free soybeans. Predation and parasitism of corn earworm eggs were similar across nematode and weed density treatments. Natural enemy populations increased to highest levels during July in closed canopy and (or) weedy soybeans, coinciding with availability of largest prey population reservoirs. A delay in colonization of very open and (or) weed free soybeans by beneficial arthropods until mid to late August allowed greater H. zea larval survival than in closed canopy and (or) weedy soybeans. Arthropod species richness was generally greatest in closed canopy and (or) weedy soybeans during mid to late July, with differences becoming nonsignificant in August and early September. Mean and maximum ambient temperatures were higher and relative humidities lower in open canopy than in closed canopy plots. These conditions were less favorable for development of pathogens and natural enemies.     

Management of Heterodera glycines by Cropping and Cultural Practices

Heterodera glycines was identified in North Carolina in 1954, although symptoms of the disease were noted in the state at least 8 years earlier. Crop rotation experiments designed to develop management systems were initiated in 1956. Two or more years in production of a nonhost crop resulted in decreases of the nematode to low or undetectable levels with acceptable subsequent yields of soybean (Glycine max). Because of almost complete dependence on resistant cultivars and (or) nematicides for nematode control, crop rotation experiments were not conducted from 1962 to 1980. Research on control of H. glycines, beginning in 1981, emphasized biological and ecological aspects of the nematode in order to determine cropping systems that restrict the nematode to nondamaging levels. Mortality during embryogenesis was high at temperatures above 30 C. Hatching of eggs occurs readily in May and June. Postinfection development takes 2-3 weeks at weekly mean temperatures of 22-29 C and is slow above and below those temperatures. Egg production is high during the late growing season. Some cultural practices such as planting early maturing cultivars in mid-to-late June and rotation with a nonhost effectively keeps populations at low levels.     

Structural and biochemical characterization of the Escherichia coli argE gene product.

The DNA sequence of a 2,100-bp region containing the argE gene from Escherichia coli has been determined. The nucleotide sequence of the ppc-argE intergenic region was also solved and shown to contain six tandemly repeated REP sequences. Moreover, the oxyR gene has been mapped on the E. coli chromosome and shown to flank the arg operon. The codon responsible for the translation start of argE was determined by using site-directed mutants. This gene spans 1,400 bp and encodes a 42,350-Da polypeptide. The argE3 allele and a widely used argE amber gene have also been cloned and sequenced. N-Acetylornithinase, the argE product, has been overproduced and purified to homogeneity. Its main biochemical and catalytic properties are described. Moreover, we demonstrate that the protein is composed of two identical subunits. Finally, the amino acid sequence of N-acetylornithinase is shown to display a high degree of identity with those of the succinyldiaminopimelate desuccinylase from E. coli and carboxypeptidase G2 from a Pseudomonas sp. It is proposed that this carboxypeptidase might be responsible for the acetylornithinase-related activity found in the Pseudomonas sp.     

A facile synthesis of 1-O-alkyl-2-(R)-hydroxypropane-3-phosphonocholine (lyso-phosphono-platelet activating factor).

The synthesis of 1-O-alkyl-2-(R)-hydroxypropane-3-phosphonocholine is described. An efficient alkylation procedure using (NaH/DMSO) catalysis is also described and applied to the synthetic scheme. The key intermediate 1-O-alkyl-2-(R)-O-benzyl-3-bromopropane was phosphonylated using tris(methylsilyl)phosphite; the resulting phosphonic acid was coupled to choline using trichloroacetonitrile/pyridine or triisopropylbenzenesulfonyl chloride/pyridine followed by catalytic hydrogenation to yield 1-O-alkyl-2(R)-hydroxypropane-3-phosphonocholine.     

Effects of genotype,habitat, and seasonal variation on iridoid glycoside content of Plantago lanceolata (Plantaginaceae) and the implications for insect herbivores

Summary We investigated the effects of genotype, habitat, and seasonal variation on production of the iridoid glycosides, aucubin and catalpol, in leaves of the common weed Plantago lanceolata. Two genotypes, one each from a lawn and an adjacent abandoned hayfield population, were clonally replicated in the greenhouse, and then planted back into the two habitats. One quarter of the plants from each treatment were harvested on each of four dates, at approximately two-week intervals. Over the course of the growing season, and in both habitats, we found a significant increase in the concentration of both aucubin and catalpol in P. lanceolata leaves. The genotypes differed in their response to environmental variation, both in time and between sites, as indicated by significant genotype x date and genotype x site interactions. Early in the season, habitat (lawn or field) had a greater effect on iridoid glycoside concentration than did plant genotype, but later in the season, plant genotype was more influential in determining the iridoid glycoside concentration. Thus, the relative palatability of Plantago genotypes to specialist and generalist herbivores may vary in time and space.     

Survival and growth of pea protoplasts after transformation by electroporation

Protoplasts from two different pea cultivars, Belman and Filby, were stably transformed by direct gene transfer using electroporation. Transgenic calli could be obtained after selection, when hygromycin resistance was used as the selective trait introduced into the protoplasts, while no transformants were obtained when kanamycin resistance was used as selective marker in either of the two pea cultivars tested. The effect of the field strength on survival and division rates of the protoplasts was studied. Two different culture systems and osmotica were compared for induction of sustained divisions in and regeneration of transgenic callus from the protoplasts. The choice of the culture system had a considerable effect on the initial division frequency of the treated protoplasts, as well as on the later growth of the colonies. Transformation efficiency was monitored by histochemical GUS assay, and the transgenic nature of the calli selected for resistance against antibiotics was confirmed by DNA analysis.     

The role of two Trichoderma reesei xylanases in the bleaching of pine kraft pulp

Summary The two major xylanases of Trichoderma reesei with different pI values and pH optima were compared for increasing the bleachability of pine kraft pulp. The efficiencies of the two enzymes acting on pulp substrate were very similar in hydrolysis yield, extraction kappa number or final brightness value. Only slight synergism between the two enzymes was observed in both hydrolysis and bleaching tests. The pH optimum of the pI 5.5 xylanase was similar in pulp treatment and in the hydrolysis of isolated substrates, and the bleaching result also correlated well with the hydrolysis of pulp xylan. By contrast, the pI 9.0 xylanase acted differently on pulp than on isolated xylans at different pH values and the pH optimum on pulp was increased. The bleachability of pulp by the pI 9.0 xylanase was improved more than expected at pH 7.0, although the hydrolysis of pulp xylan was substantially decreased. A similar phenomenon was also observed when the hydrolysis was performed in water instead of buffer. It thus appears that the degree of hydrolysis needed to obtain improved bleachability with pI 9.0 xylanase can be minimized by proper adjustment of the hydrolysis conditions. Correspondence to: J. Buchert     

Ionization state of myo-inositol 1,4,5-trisphosphate: correlation with binding properties.

The comparison between the ionization state and the binding properties on brain membrane receptors of the synthetized myo-inositol 1,4,5-trisphosphate lead to the conclusion that the biological active species may be either the monoprotonated or the fully deprotonated trisphosphate.