The R1 gene conferring race-specific resistance to Phytophthora infestans in potato is located on potato chromosome V.

Summary Late blight in potato is caused by the fungusPhytophthora infestans and can inflict severe damage on the potato crop. Resistance toP. infestans is either based on major dominantR genes conferring vertical, race-specific resistance or on minor genes inducing horizontal, unspecific resistance. A dihaploid potato line was identified which carried theR1 gene, conferring vertical resistance to allP. infestans races, with the exception of those homozygous for the recessive virulence allele of the locusV1. The F₁ progeny of a cross between this resistant parent P(R1) and P(r), a line susceptible to all races, was analysed for segregation ofR1 and of restriction fragment length polymorphism (RFLP) markers distributed on the potato RFLP map comprising more than 300 loci. TheR1 locus was mapped to chromosome V in the interval between RFLP markers GP21 and GP179. The map position ofR1 was found to be very similar to the one ofRx2, a dominant locus inducing extreme resistance to potato virus X.     

Sequence of a novel HLA-DQB1 allele

The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence data base and have been assigned the accesion number M74842. The name DQB1*0304 has been officially assigned by the WHO Nomenclature Committee in November 1991. This follows the agreed policy that, subject to the conditions stated in the most recent Nomenclature Report (WHO Nomenclature Committee for factors of the HLA system, 1991), names will be assigned to new sequences as they are identified. List of such new names will be published in the following WHO Nomenclature Report.     

Production and properties of xylanases from thermophilic actinomycetes

30 strains of xylanolytic thermophilic actinomycetes were isolated from composted grass and cattle manure and identified as members of the generaThermomonospora, Saccharomonospora, Microbispora, Streptomyces andActinomadura. Screening of these strains for extracellular xylanase indicated that strains ofSaccharomonospora andMicrobispora generally were poor xylanase producers (0.5–1.5 U/ml) whereas relatively high activities were observed in cultures ofStreptomyces andActionomadura (4–12 U/ml).A preliminary characterization of the enzymes of strains of the latter genera suggested that xylanases of all the strains ofActinomadura exhibited higher thermostabilities than those ofStreptomyces. To evaluate the potential of thermophilicActinomadura for industrial applications, xylanases of three strains were studied in more detail. The highest activity levels for xylanases were observed in cultures grown on xylan and wheat bran. The optimal pH and temperature for xylanase activities ranged from 6.0 to 7.0 and 70 to 80°C. The enzymes exhibited considerable thermostability at their optimum temperature. The half-lives at 75°C were in the range from 6.5 to 17h. Hydrolysis of xylan by extracellular xylanases yielded xylobiose, xylose and arabinose as principal products. Estimated by the amount of reducing sugars liberated the degree of hydrolysis was 55 to 65%. Complete utilization of xylan is presumably achieved by -xylosidase activities which could be shown to be largely cell-associated in the 3Actinomadura strains.     

Nucleotide sequence of Rattus norvegiens mitochondrial DNA that includes the genes for tRNAile, tRNAgln and tRNAf-met

The nucleotide sequence of a segment of mtDNA from Rattus norvegiens (rat) which contains the genes for tRNA^ile, tRNA^gl and tRNA^f-met has been determined. A detailed comparison has been made between this sequence and the corresponding sequences of mouse, human and bovine mtDNAs with regard to the primary and secondary structure of the tRNA genes, the regions connecting the tRNA genes, and the regions flanking the tRNA genes which code for the carboxyl terminus of URF-1 and the amino terminus of URF-2. No differences were found in the nucleotide sequences of the genes for tRNA^ile, tRNA^gln and tRNA^f-met in mtDNAs from three different female lines of rats (SASCO-1, SASCO-2 and Wild-UT) that differ by substitutions of 0.8% to 1.8% of their total nucleotides.     

Effects of chronic administration of somatostatin on rat exocrine pancreas

We studied the effects of somatostatin on synthesis of pancreatic DNA, RNA and protein and on pancreatic weight and contents of DNA, protein, amylase and chymotrypsinogen in rats. In short term synthesis studies, rats were injected with 100 micrograms . kg-1 somatostatin or 0.15 M NaCl (control) at times 0, 8 and 16 h. Eight rats from each treatment group were killed 2, 4, 8, 12, 16, 20 and 24 h after beginning treatment. Incorporation rates in vivo of [3H]thymidine into DNA, [3H]uridine into RNA and [14C]phenylalanine into total protein were significantly depressed by somatostatin. In long term studies, four groups of 12 rats were injected every 8 h for 5 days with 0.15 M NaCl or 11, 33 or 100 micrograms . kg-1 somatostatin. Body weight was unaffected but pancreatic contents of DNA, protein and enzymes were significantly decreased by somatostatin. Administration of somatostatin inhibits DNA, RNA and protein synthesis in exocrine pancreas with resulting decreases in DNA and enzyme contents.     

La criocerine: Nouvel alcaloide isole des tiges de Crioceras dipladeniiflorus

Seven indolic alkaloids have been isolated from the stem bark of Crioceras dipladeniiflorus. One of them is new and has been called criocerine. Its structure, 7, has been established by use of physical data and chemical correlation with [Δ¹⁴]-vincamine.     

Effets de la chirurgie á coeur ouvert sur les mécanismes de défense contre lea infections bactériennes

Extracorporeal circulation during open-heart surgery may damage cellular and humoral factors in the blood. Phagocytic functions of circulating polymorphonuclear leukocytes were investigated in 10 patients 1 day before, then 1 hour, 2, 4 and 10 days after open-heart surgery. Transient diminutions in the phagocytic capacity of polymorphs was found for Staphylococcus aureus and Escherichia coli in one patient, and E. coli only in two patients up to the 4th postsurgical day. A positive correlation was found between the duration of extracorporeal circulation and the transient diminutions in phagocytic capacity for these three patients. However, the bactericidal capacity of polymorphs and their capacity to reduce nitroblue tetrazolium were normal in all patients. The serum concentrations of total hemolytic complement, C3, IgG and IgM were generally diminished up to the 4th day after surgery, but the opsonic power of the serum was almost normal in all the patients.