Developmental regulation of a prestalk- and stalk-enriched protein in Dictyostelium discoideum

Abstract. Monoclonal antibodies reactive with proteins specifically present either in the prespore cells or the prestalk cells of Dictyostelium discoideum were obtained. Four of them recognized prespore-enriched proteins, as shown by both immunoblotting assays and immunofluorescent staining. The other monoclonal antibody ( mab150 ) produced more than 10 protein bands when reacted with both prespore and prestalk cell extracts in immunoblotting assays. However, a protein band with molecular weight 35 000 (st35) was specifically detected in prestalk cells as well as mature stalk cells. St35 was solubilized from the Triton X-100 insoluble fraction of mature stalks by sodium dodecyl sulfate (SDS). The purified sample gave a single spot on two-dimensional gel electrophoresis, with pI of 5.0. During development, st35 first appeared at the tipped aggregate stage and accumulated up to stalk-cell formation without modification. The protein was not lost even when slugs were disaggregated. The importance of the tipped aggregate stage for prestalk differentiation as well as prespore differentiation is discussed.     

Identification of glutamic acid 186 affinity-labeled by 2,3-epoxypropyl alpha-D-glucopyranoside in soybean beta-amylase

Soybean beta-amylase was modified with 2,3-epoxypropyl alpha-D-[U-14C]glucopyranoside ([14C]alpha-EPG), a radioactive affinity-labeling reagent for beta-amylase, until it lost 95% of its enzyme activity. After S-carboxymethylation at pH 8.0 of SH groups, the modified enzyme was digested at pH 7.0 with Achromobacter protease I and the digest was fractionated by reverse-phase HPLC. A radioactive peptide was finally isolated and its amino acid sequence was determined to be 181Leu-Gly-Pro-Ala-Gly-Glu186. Radioactivity derived from [14C]-alpha-EPG was found exclusively at Glu-186, the gamma-carboxyl group of which is esterified with the affinity label. It was concluded that the carboxylate of Glu-186 is a functional group at the catalytic site of soybean beta-amylase.     

Production of acetic acid by a repeated batch culture with cell recycle ofAcetobacter aceti

Summary A comparison of volumetric production rates of acetic acid inAcetobacter aceti M23 was conducted for repeated batch (RB), cell-recycling repeated batch (CRB) and continuous (C) cultures. Best result was obtained with CRB culture. The magnification of productivity was 1.7 (to RB culture) and 3.3 (to C culture) for aiming final acetic acid concentration of 60 g/l and 42 g/l, respectively.     

Cerebral cortical and brainstem areas related to the central control of lens accommodation in cat and monkey.

1. Studies on the central nervous system related to lens accommodation in cat and monkey were reviewed. 2. During the last decade, a considerable amount of neurophysiological data on the peripheral innervation of the ciliary muscle, properties of parasympathetic oculomotor neurons and mesencephalic reticular neurons have accumulated. 3. Neurophysiological and anatomical evidence supporting the contribution of the cerebellum to lens accommodation has been obtained. 4. Recently, cerebral cortical neurons in the parieto-occipital cortex with activities related to lens accommodation were found in cat and monkey.     

Application of AFLPs to the characterization of grapevine Vitis vinifera L. genetic resources. A case study with accessions from Rioja (Spain)

 AFLPs were used to characterize 67 different grapevine accessions from a collection of D.O.Ca. Rioja in Spain. A correct selection of primers and selective nucleotides allowed us to maximize the number of amplified fragments analyzed per reaction yielding an average of 100 per reaction, 49% of which were polymorphic. Based on the presence or absence of amplified fragments for each genotype resulting from a reaction with two primer combinations, we have established the genetic similarity between the different accessions in the collection. These results allowed us to resolve different genotypes maintained under the same name (homonyms) and to identify the same genotype under different names (synonyms) thus permitting the elimination of redundant germplasm. Furthermore, by providing information on more than 50 polymorphic loci per reaction, a few reactions were sufficient to identify distinct AFLP patterns characteristic of specific clones, with different agronomic and organoleptic features, belonging to the same cultivar. The possibility for clonal identification, shown here for grapevines, can have important implications in the protection and management of clonal selections. Received: 1 February 1998/Accepted: 25 February 1998     

Cell division cycle genes nda2 and nda3 of the fission yeast Schizosaccharomyces pombe control microtubular organization and sensitivity to anti-mitotic benzimidazole compounds

Two genes, nda2 and nda3, previously defined by cold sensitive nuclear division arrest (nda) mutations in the fission yeast Schizosaccharomyces pombe were studied. A mutant nda2-KM52 was found to be supersensitive (at the permissive temperature) to the tubulin-binding drugs such as thiabendazole, methylbenzimidazol-2yl carbamate and nocodazole. A single mutation in nda2 appears to cause both drug supersensitivity and cold sensitivity. The defective phenotypes of nda2-KM52 with a low concentration of the drugs were characterized by nuclear displacement and anomalously situated spindle pole bodies. The allele of the other mutant, nda3-KM311, was sh216 to be linked closely to the ben1 locus, which determines resistance to the drug. The identity of ben1 and nda3 genes was proved by a newly isolated mutant ben1-TB1005; it manifests ben1 resistance and the cold sensitive nda3 phenotype. At 22 degrees C, ben1-TB1005 showed cell branching and deformation characteristic of nda3-KM311. Eleven mutants supersensitive to thiabendazole were newly isolated by replica plating. Four strains were mapped in nda2, while the other four were in nda3. Most of the isolated mutants were blocked at nuclear division in the presence of a low concentration of the drug. Thus, the products of genes nda2 and nda3 (ben1) interact directly or indirectly with the drugs and control, in different ways, microtubular organization in the cells of S. pombe.