Occurrence of Gibberella zeae strains that produce both nivalenol and deoxynivalenol.

By single ascospore isolation, several sets of asci containing eight ascospores were isolated from perithecia of Gibberella zeae. Of these sets, seven were investigated for their ability to produce 8-ketotrichothecene mycotoxins on rice grains. Analyses were made with gas chromatography-mass spectrometry and gas chromatography with 63Ni electron capture detection. Of 56 total isolates, 11 produced nivalenol, 4-acetylnivalenol, and deoxynivalenol, 1 produced nivalenol and deoxynivalenol, 7 produced deoxynivalenol and 3-acetyldeoxynivalenol, 19 produced deoxynivalenol and 15-acetyldeoxynivalenol, and 6 produced deoxynivalenol and both 15- and 3-acetyldeoxynivalenol. The remaining 12 isolates produced nivalenol and 4-acetylnivalenol. All isolates of G. zeae that we examined could produce 8-ketotrichothecenes in this investigation. This report is the first to demonstrate the presence of G. zeae isolates producing both nivalenol and deoxynivalenol. In addition, differences in the production between 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol are discussed in relation to culture conditions.     

The complete nucleotide sequence of a 16S ribosomal RNA gene from tobacco chloroplasts: Recombinant plasmid; sequence homology; stem and loop structure

The complete nucleotide sequence of a 16S ribosomal RNA gene from tobacco chloroplasts has been determined. This nucleotide sequence has 96% homology with that of maize chloroplast 16S rRNA gene and 74% homology with that of Escherichia coli16S gene.The 3′ terminal region of this gene contains the sequence ACCTCC which is complementary to sequences found at the 5′ termini of prokaryotic mRNAs.The large stem and loop structure can be constructed from the sequences surrounding the 5′ and 3′ ends of the 16S gene. These observations demonstrate the prokaryotic nature of chloroplast 16S rRNA.     

Cloning and characterization of a plasmid DNA from anacystis nidulans 6301

A plasmid DNA of Anacystis nidulans 6301 was isolated by CsCl-EtBr centrifugation. The Mr of the plasmid, named pBA1, was estimated to be 5.04 +/- 0.26 X 10(6) by electron microscopic analysis and 5.2 X 10(6) by agarose gel electrophoresis. The pBA1 DNA was opened at a unique site with BamHI and cloned in pBR322 vector propagated in Escherichia coli HB101 cells. The recombinant plasmid, named pBAS18, was digested with various restriction endonucleases and its cleavage map was constructed. Based on this result, the cleavage map of the pBA1 plasmid is presented.     

Elongation of oligonucleotides in the 3'-direction with activated mononucleotides and their analogs using RNA ligase.

P1-Adenosine 5'-P2-2',3'-ethoxymethylidene nucleosides [A(5')ppN(Em)] from four common nucleosides have been prepared and used for single addition of nucleotides to elongate oligonucleotide chains in the 3'-direction in RNA ligase reaction. U-U-C, T-U-C and A-C-C were used as acceptors. Structural dependence in these acceptors was found to be smaller compared to joining reactions between oligonucleotides. Adenosine analogs including 8-bromo-, 2'-fluoro-, 2'-azido-, 8,2'-O-cyclo-, 8,2'-S-cyclo-adenosine, arabinosyladenine and 2'-deoxyadenosine were added to the 3'-end of A-C-C by adenylation chemically followed by joining with RNA ligase. Symmetrical 5'-pyrophosphates of 8-bromo-, 2'-fluoro- and 2'-azido-adenosine were not recognized as donor substrates.     

Metal coordination core of bleomycin : comparison of metal complexes between bleomycin and its biosynthetic intermediate.

On the basis of electron spin resonance results, the 1:1 Cu(II), Co(II), Co(II)-O₂, and Ni(III) complexes of bleomycin(BLM) have been compared with the corresponding metal complexes of its biosynthetic intermediate(P-3A). The present study suggests that (1) P-3A is an useful ligand for the clarification of metal-binding sites of BLM; (2) the secondary amine, pyrimidine ring nitrogen, deprotonated peptide nitrogen of histidine residue, and histidine imidazole groups as planar ligand donors, and the α-amino group as axial donor, are substantially important for metal-coordination of BLM; and (3) the sugar and bithiazole portions of BLM probably contribute to stabilization of Co(II)-O₂ adduct complex and axial sixth coordination of Cu(II) and Ni(III) complexes.     

Scanning electron-microscopy of starch granules, with or without amylase attack

Scanning electron-microscopy (SEM) revealed that, for starch granules relatively susceptible to amylase, numerous pin holes could be observed on the surfaces of granules attacked by amylase. We also observed that the pores penetrated into the inner layers of granules during the enzyme action and some of the granules exhibited a terraced or step-shaped apperance in their inner portions. These internal characteristics are most probably indicative of layered internal structures of the granules. The other characteristic observations by SEM were striated structures on the surfaces of starch granules of banana, lily, and lotus attacked by pancreatin.     

Studies on the mechanism of the lipase reaction. II. Comparative studies on the adsorption of lipases and various proteins at the air-water interface.

Adsorption of lipases (EC 3.1.1.3) and various proteins at the air-water interface has been investigated in relation to the mechanism of lipase reaction. Aqueous solutions of lipases and denaturated proteins show surface activity as strong as that of synthetic detergents. However, ths surface activity of esterases and various other proteins is little or none. By foam fractionation it was shown that lipases were adsorbed at the air-water interface and the adsorption followed the equation of Langmuir's adsorption isotherm. The properties of lipase at the interface are discussed in relation to the mechanism of lipase reaction and the differences from the esterase reaction.     

Intranuclear silicon detection in a subcutaneous connective tissue cell by energy-dispersive x-ray miscroanalysis using fresh air-dried spread.

Silicon was detected by energy-dispersive x-ray microanalysis in the nucleus of a subcutaneous connective tissue cell of mice fed normally. To eliminate contamination, pieces of connective tissue were spread on copper grids and examined without any treatment by an energy-dispersive spectrometer with a scanning transmission apparatus attached to an electron microscope. Scanning transmission electron microscopy of the spread has demonstrated a well-preserved ultrastructure. Fibrous structures, nuclei and nucleoli of cells and mitochondrial granules were recognized. Electron probe analysis showed peaks for silicon at three spots on the nucleus of a cell in addition to those for phosphorus, sulfur, chlorine, potassium and calcium, whereas no peak of silicon could be detected at the spots on nuclei of other cells, mitochondrial granules and electron-lucent area on the same grid as the above. Silicon appears to play a significant role in the nucleus. Applicability of the technique to know the distribution of easily contaminating elements and diffusible substances is shown.     

The variable refractivity of the protein or polypeptide hormone-producing cells showing a unique luminescence in the dark-field microscope

Synopsis When cryostat sections of endocrine tissue were examined in a dark-field microscope, a brilliant granular luminescence was revealed in the endocrine cells thought to be concerned with protein or polypeptide hormone production. The sections were prepared from fresh materials either frozen in a cryostat chamber at –25°C, in dry ice-acetone, or fixed in formalin-calcium for 24 hr. The neurosecretory substance in the hypothalamus and the posterior lobe of the pituitary showed a blue luminescence; the acidophil cells of the anterior lobe of the pituitary, orange; basophil cells, green or blue; intermediate lobe cells, no luminescence; thyroid C cells, white-blue; pancreatic A cells, blue; B cells, orange; adrenomedullary cells, greenish blue; enterochromatin cells, green; and other endocrine cells in the gastrointestinal tract, blue or orange. After tearing and spreading the pituitary and hypothalamus with a pair of needles on a glass slide, and examining the teased specimen by dark-field microscopy, various cells of different luminescent colours became apparent in the anterior lobe of the pituitary, a blue fluorescent substance in the posterior lobe, and neurosecretory cell bodies in the hypothalamus. The different colours appear to be inherent in the granules of living tissues.     

Sulfonamide-based non-alkyne LpxC inhibitors as Gram-negative antibacterial agents

We attempted to optimize sulfonamide-based non-alkyne LpxC inhibitors by focusing on improvements in enzyme inhibitory and antibacterial activity. It was discovered that inhibitors possessing 2-aryl benzofuran as a hydrophobe exhibited good activity. In particular, compound 21 displayed impressive antibacterial activity (E. coli MIC = 0.063 μg/mL, K. pneumoniae MIC = 0.5 μg/mL, and P. aeruginosa MIC = 0.5 μg/mL), and is a promising lead for further exploration as an antibacterial agent.