Response of Soybean to Heterodera glycines Races 1 and 2 in Different Soil Types

Experiments were conducted for 3 years at four locations and 1 year with six soil types at a common location in North Carolina to determine damage and control-cost functions for Heterodera glycines races 1 and 2 on soybean. In the experiments on native loamy sand and sandy soils, tolerance limits for initial population densities were 0 or very low, whereas in a muck, the tolerance limit was 315 eggs/500 cm³ soil. The aggressive race 2 was more damaging than race 1 in Lakeland sand and Norfolk loamy sand. The crop response was not different between races in the Appling sandy clay loam and Belhaven muck. Soybean yield responses to H. glycines were linear in six soil types in microplots at a common site. The amount of damage varied among these soil types, with lowest yields in the muck because of severe drought stress in this soil. An exponential function adequately described soybean yield response relative to nematode control with increasing rates of aldicarb in Norfolk loamy sand. Treatment with aldicarb in the Lakeland sand decreased the effective egg population of H. glycines but had only a minor effect in the muck.     

HIV-specific antibody among voluntary blood donors in Lower Saxony (FRG)

Anti-HIV test results of the Red Cross Blood Transfusion Service of Lower Saxony from 1 June 1985 to 31 July 1986 inclusive were analysed retrospectively. Nine out of 70,936 donors who had not donated blood before 1 June 1985 (first-time donors) and 9 out of 261,231 donors who had donated blood before this date (repeating donors) were found anti-HIV confirmed positive at the time of the first blood donation during the study period. The prevalence of HIV antibody in first-time donors was significantly higher than in repeating donors (p less than 0.01). It was concluded that some members of risk groups used blood donation to obtain an anti-HIV test result. One out of 30,300 blood donations was confirmed anti-HIV positive. The results of this study justify the transfusion of blood donations that are reactive only in the initial ELISA test.     

Glucocorticoid receptor binds cooperatively to adjacent recognition sites.

In order to define the mechanism of synergistic induction mediated by multiple glucocorticoid response elements (GRE), the affinity of the glucocorticoid receptor to a single or duplicated GRE was analyzed by gel retardation, nitrocellulose filter binding and by footprinting experiments. Direct measurement of the relative affinity and indirect determination by competition showed greater than 10-fold higher affinity of the glucocorticoid receptor to a duplicated GRE when compared to a single element. Maximal stability of the GRE-receptor complex was obtained using two closely spaced GREs positioned on the same side of the DNA helix. Increasing the distance or changing the helical position of the GREs considerably increased the off rate of the receptor. DNase I footprinting shows in addition to the protection of the GRE region, an altered pattern in the nonprotected intervening DNA indicating structural alteration of the DNA helix by the receptor bound to adjacent GREs.     

Histone genes of Volvox carteri: DNA sequence and organization of two H3-H4 gene loci.

Two Volvox genomic clones each containing a pair of histone H3-H4 genes were sequenced. In both loci the H3 and H4 genes show outwardly divergent polarity, their coding regions being separated by short intercistronic sequences containing TATA boxes and a conserved 14-bp element. The 3' untranslated regions contain a characteristic motif with hyphenated dyad symmetry otherwise only found associated with animal histone genes. Derived amino acid sequences of histones H3 and H4 are highly conserved and identical between the two sets. The Volvox H3 genes both contain one intron whose relative position is shifted by one basepair. Sequence comparisons led to a new interpretation of intron sliding. The Volvox H3 gene structure combines the exon-intron organization of fungal H3 and vertebrate H3.3 genes with a termination signal typical for animal H3.1 genes. These features are discussed in view of histone gene evolution.     

Gene expression during CAM induction under salt stress in Mesembryanthemum: cDNA library and increased levels of mRNA for phosphoenolpyruvate carboxylase and pyruvate orthosphosphate dikinase

Mesembryanthemum crystallinum responds to high salinity in the soil by shifting the mode of carbon assimilation from the C3 mode to Crassulacean acid metabolism (CAM). Several enzymes of carbon metabolism have increased apparent activities in the CAM mode, including phosphoenolpyruvate carboxylase (PEPcase) and pyruvate orthophosphate dikinase (PPDK). We have identified cDNA clones for PEPcase and PPDK by immunological screening of a cDNA library constructed in the protein expression vector lambda gt11. The clones were characterized by immunoblotting and RNA blotting techniques. RNA blotting showed that during CAM induction the steady-state level of mRNAs for both PEP case and PPDK increased.Abbreviations IPTG isopropyl thiogalactoside - PEP phosphoenolpyruvate - PEPcase phosphoenolpyruvate carboxylase - PPDK pyruvate orthophosphate dikinase - Xgal-5 bromo-4-chloro-3-indolyl-beta-D-galactopyranoside     

Citrate utilization by free and immobilized Streptococcus lactis subsp. diacetylactis in continuous culture

Summary The effects of pH, temperature and concentration of citrate were investigated to achieve an optimal production of diacetyl, acetoin and C₂ compounds such as acetaldehyde, acetate and ethanol for free and immobilized cells. The critical conditions of culture, 22°C, pH 4.8, increased the production of C₄ compounds (diacetyl, acetoin, 2, 3 butylene glycol), C₂ compounds (acetaldehyde, ethanol, acetate) and formate. A higher yield of C₂ and C₄ compounds was observed for the immobilized cells than for the free cells in continuous culture. At 75 mMol/l of citrate, the citrate bioconversion yield was 42.8% and 80% for free and immobilized cells, respectively. This paper discusses citrate and lactose utilization and NADH₂ part on diacetyl reduction.     

Cloning and sequencing of the genes encoding the large and the small subunits of the H2 uptake hydrogenase (hup) of Rhodobacter capsulatus

Summary The structural genes (hup) of the H₂ uptake hydrogenase of Rhodobacter capsulatus were isolated from a cosmid gene library of R. capsulatus DNA by hybridization with the structural genes of the H₂ uptake hydrogenase of Bradyrhizobium japonicum. The R. capsulatus genes were localized on a 3.5 kb HindIII fragment. The fragment, cloned onto plasmid pAC76, restored hydrogenase activity and autotrophic growth of the R. capsulatus mutant JP91, deficient in hydrogenase activity (Hup^-). The nucleotide sequence, determined by the dideoxy chain termination method, revealed the presence of two open reading frames. The gene encoding the large subunit of hydrogenase (hupL) was identified from the size of its protein product (68108 dalton) and by alignment with the NH₂ amino acid protein sequence determined by Edman degradation. Upstream and separated from the large subunit by only three nucleotides was a gene encoding a 34 256 dalton polypeptide. Its amino acid sequence showed 80% identity with the small subunit of the hydrogenase of B. japonicum. The gene was identified as the structural gene of the small subunit of R. capsulatus hydrogenase (hupS). The R. capsulatus hydrogenase also showed homology, but to a lesser extent, with the hydrogenase of Desulfovibrio baculatus and D. gigas. In the R. capsulatus hydrogenase the Cys residues, (13 in the small subunit and 12 in the large subunit) were not arranged in the typical configuration found in [4Fe–4S] ferredoxins.