Effects of light-dark cycles on the circadian conidiation rhythm inNeurospora crassa

The effects of 24 hr light-dark cycles on the circadian conidiation rhythm inNeurospora crassa were compared among will-typefrq ⁺ and clock mutantsfrq ⁺,frq ³,frq ⁷,frq ⁹ andfrq ¹¹. The minimum length of the light period necessary for complete entrainment to the light-dark cycles was almost 2 hr infrq ⁺,frq ³ andfrq ⁷ strains. The minimum duration of the dark period necessary for the appearance of circadian conidiation was almost 4 hr in all of the strains except thefrq ¹¹ strain. The phase of the conidiation rhythm was dependent on the light to dark transition in thefrq ¹ strain in all light-dark cycles examined and in thefrq ⁺ andfrq ³ strains when the light period was shorter than 16 hr. In contrast, the phase of thefrq ⁷ strain was dependent on the light to dark transition when the light period was shorter than 10 hr.     

Immunostimulatory activities of monoglycosylated α-d-pyranosylceramides

We compared the immunostimulatory effects of chemically synthesized α-galactosylceramides (α-GalCers), α-glucosylceramides (α-GluCers), 6″-monoglycosylated α-GalCer and 6″- or 4″-monoglycosylated α-GluCer and made the following observations: (1) the length of the fatty acid side chain in the ceramide portions greatly affects the immunostimulatory effects of α-GalCers and α-GluCers; (2) the configuration of the 4″-hydroxyl group of the inner pyranose moiety plays an important role in the immunostimulatory effects of monoglycosylated α- -pyranosylceramides; (3) the free 4″-hydroxyl group of the inner pyranose of monoglycosylated α- -pyranosylceramides plays a more important role in their immunostimulatory effects than the free 6″-hydroxyl group.     

Plant-wide names for partial cDNA sequences of rice usingBlast and4th dimension

A total of 687 DNA sequence accessions from the Mendel database (release 1.04, 3 November 1994) assigned standardized designations for plant genes and gene products were used in aBLAST similarity search of 7557 rice partial cDNA sequences and 287 other rice sequences from the Japanese Rice Genome Research Program. We describe procedures for data manipulation, import and export from and to Macintosh and Unix, and the use of 4th Dimension relational database management system (RDBMS) in data processing. Altogether 275 sequences showed strong similarity hits. Using the CPGN nomenclature, we assign putative designations for genes and gene products. Assignments include representatives of 26 gene products, including 58 cDNA sequences similar to α-tubulins (TubA), 23 similar to β-tubulins (TubB) and 51 similar to cytosolic subunit C of glyceraldehyde-3-phosphate dehydrogenase (NAD) (GapC). The results of the similarity searches are listed and are also available electronically. The assignments have been submitted to the CPGN working groups for verification and for later inclusion in the GenBank/EMBL/DDBJ sequence databases, which will include the standardized designations in the accession data fields. Member of the ISPMB Commission on Plant Gene Nomenclature, representing the Rice Genome Research Program of Japan. Reprint requests to T. Sasaki.     

Genetic analysis of the structure and function of RNase P fromE. coli

A brief review of the genetic studies on ribonuclease P (RNase P) fromEscherichia coli is presented. Temperature-sensitive mutants ofE. coli defective in tRNA processing were isolated by screening cells which were unable to synthesize a suppressor tRNA at restrictive temperature. Structural analysis of accumulated tRNA precursors showed that the isolated mutants were defective in RNase P activity. Analyses of the mutants revealed that the enzyme is essential for the synthesis of all tRNA molecules in cells and that the enzymes consists of two subunits. Analyses of the isolated mutants revealed a possible domain structure of the RNA subunit of the enzyme.Abbreviations E. coli Escherichia coli - RNase P ribonuclease P     

High level of GUS gene expression driven by pollen-specific promoters in electroporated lily pollen protoplasts

Gene constructs that contained the -glucuronidase (GUS) gene under the control of a pollen-specific Zm13 promoter from maize and a LAT52 promoter from tomato were introduced by electroporation into pollen protoplasts isolated from bicellular pollen grains of Lilium longiflorum. After 20 h in culture, the pollen protoplasts exhibited the apparent expression of GUS in a fluorometric assay. The GUS activity induced under the control of the Zm13 promoter was over 10 000 times higher than activity in the control (with no DNA or without electroporation). By contrast, the GUS gene was nearly silent in the lily microspore protoplasts and generative cell protoplasts. The GUS activity driven by the Zm13 and LAT52 promoters was also detected by a cytochemical assay. The frequency of blue-staining pollen protoplasts was about 70% in the case of the Zm13 promoter. The efficiency of gene transfer by electroporation was much higher than by particle bombardment. This protoplast-specific electroporation system is suitable for rapid and reliable examination of pollen-specific promoters, being as good as the particle bombardment system.     

Activation of ATPase Activity in the Chromatin Fraction of Pea Nuclei by Calcium and Calmodulin

ATPase, especially the Ca^2$-dependent enzyme, in the chromatinfraction isolated from nuclei of pea seedlings was activatedby bovine brain calmodulin and by protein that was judged tobe calmodulin from its Ca^2$-dependent activation of NAD kinase.This calmodulin-dependent ATPase activity was blocked by calmodulin-specificinhibitors. (Received July 11, 1983; Accepted October 24, 1983)     

Binding of aluminium to DNA of DNP in pea root nuclei

The association of absorbed aluminium (Al) with nuclei in Alaskapea roots was shown by zonal centrifugation of isolated nuclei.In nuclei, 73% of the total incorporated Al was detected inthe DNP fraction. Furthermore, Al in DNP was found to be boundspecifically to DNA by gel filtration of dissociated DNP. (Received March 19, 1977; )     

Possible influence of lysophospholipase on the production of 1-acyl-2-acetylglycerophosphocholine in macrophages.

The rate of production of 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (PAF) and 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (acylPAF) was measured in macrophages following the incorporation of [3H]acetate. Upon activation by A23187, guinea pig alveolar macrophages incorporated [3H]acetate into PAF, but a little radioactivity was found in acylPAF. However, labeling of acylPAF and PAF with [3H]acetate was greatly enhanced in A23187-stimulated alveolar macrophages that had been pretreated with phenylmethanesulphonyl fluoride (PMSF). [3H]PAF was predominantly converted to 1-[3H]alkyl-2-acyl glycerophosphocholine, but [14C]acylPAF rapidly hydrolyzed to 14C-labeled free fatty acid by the incubation with lysates prepared from macrophages. The deacetylation of [14C]acylPAF and [3H]PAF by acetylhydrolase and also the hydrolysis of [14C]lysoPC by lysophospholipase were strongly inhibited in macrophages that had been pretreated with PMSF, while PMSF failed to inhibit the activities of acetyltransferase and acyltransferase. The relative proportions of PAF and acylPAF were quite different in different types of cells. In contrast to alveolar macrophages, peritoneal macrophages, neutrophils and spleen cells from guinea pigs incorporated 2-4 times more [3H]acetate into acylPAF than into PAF. The presence of high levels of acylPAF in peritoneal macrophages was confirmed by GLC-MS analysis. The activities of lysophospholipase, acetylhydrolase and acetyltransferase were measured in alveolar and peritoneal macrophages to determine whether the preferential formation of acylPAF as compared to PAF in peritoneal macrophages was due to differences in these activities between alveolar and peritoneal macrophages. The activity of acetylhydrolase of peritoneal macrophages was almost the same as that in alveolar macrophages. The activity of acetyltransferase in peritoneal macrophages was about half of that in alveolar macrophages. However, the activity of lysophospholipase in peritoneal macrophages was one-sixth of that in alveolar macrophages. These results suggest that lysophospholipase is one of the primary factors involved in the control of the production of acylPAF in activated cells, and that it acts by modulating the availability of lysoPC for the synthesis of acylPAF. Furthermore, high levels of activity of lysophospholipase allow the preferential formation of PAF, via the rapid hydrolysis of lysoPC which would act as a competitive inhibitor of the incorporation of acetate into lysoPAF.     

Microbial asymmetric hydrolysis of N-acetyl-1-methyl-3-phenylpropylamine to optically active 1-methyl-3-phenylpropylamine

Summary The asymmetric hydrolysis of N-acetyl-1-methyl-3-phenypropylamine (MPAc) by microorganisms was investigated. Various bacteria belonging to the genera Bacillus, Agrobacterium, Corynebacterium, Arthrobacter, Brevibacterium, Cellulomonas, Acinetobacter, Nocardia and Rhodococcus showed this hydrolysing activity and yielded (S)-1-methyl-3-phenylpropylamine (MPPA). Using washed cells of N. erythropolis IAM 1440, 15.1 mg/ml of (S)-MPPA was formed, with a 38.8% conversion yield and high stereoselectivity (97.9% enantiomeric excess), in an organic solvent-water diphase system. The same (S)-amine and (S)-1-phenylethylamine were also produced in good yields from the valeryl and isovaleryl derivatives of MPPA, and N-acetyl-1-phenylethylamine, respectively.