Acetyl-CoA Carboxylase in Higher Plants: Most Plants Other Than Gramineae Have Both the Prokaryotic and the Eukaryotic Forms of This Enzyme

The presence and the absence of a prokaryote type and a eukaryotetype of acetyl-CoA carboxylase (EC 6.4.1.2 [EC] ; ACCase) were examinedin members of 28 plant families by two distinct methods: thedetection of biotinylated subunits of ACCase with a streptavidinprobe, and the detection of the accD gene, which encodes a subunitof the prokaryotic ACCase, by Southern hybridization analysis.The protein extracts of all the plants studied contained a biotinylatedpolypeptide of 220 kDa, which was probably the eukaryotic ACCase.All the plants but those belonging to Gramineae also containeda biotinylated polypeptide of ca. 35 kDa, which is a putativesubunit of the prokaryotic ACCase. In all plants but those inGramineae, the ca. 35 kDa polypeptide was found in the proteinextracts of plastids, while the 220 kDa polypeptide was absentfrom these plastid extracts. The plastid extracts of the plantsin Gramineae contained the 220 kDa polypeptide, as did the homogenatesof the leaves. Southern hybridization analysis demonstratedthat all the plants but those in the Gramineae contained theaccD gene. These findings suggest that most higher plants havethe prokaryotic ACCase in the plastids and the eukaryotic ACCasein the cytosol. Only Gramineae plants might contain the eukaryoticACCases both in the plastids and in the cytosol. The originof the plastid-located eukaryotic ACCase in Gramineae is discussedas the first possible example of substitution of a plastid geneby a nuclear gene for a non-ribosomal component. ⁴Present address: Plant-Growth Regulation Laboratory, The Instituteof Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako,351-01 Japan ⁵Present address: Laboratory of Plant Molecular Biology, Schoolof Agricultural Sciences, Nagoya University, Chikusa-ku, Nagoya,464-01 Japan     

Synthesis and biological activities of N-acetyl-1-thiomuramoyl-L-alanyl-D-isoglutamine and some of its lipophilic derivatives

N-Acetyl-1-thiomuramoyl-L-alanyl-D-isoglutamine and some lipophilic analogs were synthesized from benzyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-3-O-[D-1-(methoxycarbonyl)ethyl ]- alpha-D-glucopyranoside (1). O-Debenzoylation of 2, derived from 1 by oxidation, gave 2-acetamido-2-deoxy-4,6-O-isopropylidene-3-O-[D-1-(methoxycarbonyl)ethyl ]-D-glucopyranose (3). Condensation of the alkoxy-tris(dimethylamino)phosphonium chloride (4), formed from 3 by the action of carbon tetrachloride and tris(dimethylamino)phosphine, with potassium thioacetate afforded 2-acetamido-1-S-acetyl-2-deoxy-4,6-O-isopropylidene-3-O-[ D-1-(methoxycarbonyl)ethyl]-1-thio-beta-D-glucopyranose (8). Coupling of the acid 9, obtained from 8 by hydrolysis and subsequent S-acetylation, with the methyl ester of L-alanyl-D-isoglutamine gave N-[2-O-(2-acetamido-1-S-acetyl-2,3-dideoxy-4,6-O- isopropylidene-1-thio-beta-D-glucopyranose-3-yl)-D-lactoyl]-L-alan yl-D- isoglutamine methyl ester (10), which was converted, via O-deisopropylidenation, S-deacetylation, and de-esterification, into the N-acetyl-1-thiomuramoyl dipeptide. Condensation of 11 (derived from 10 by S-deacetylation) and of 12 (obtained from 10 by S-deacetylation and de-esterification) with various acyl chlorides yielded the corresponding 1-S-acyl-N-acetylmuramoyl-L-alanyl-D-isoglutamine derivatives, which were converted into the desired, lipophilic 1-thiomuramoyl dipeptides by cleavage of the isopropylidene group. Condensation of 11 with the alkyl bromides yielded the 1-S-alkyl derivatives, which were also converted, via O-deisopropylidenation and de-esterification, into the corresponding 1-S-alkylmuramoyl dipeptides. The biological activities were examined in guinea-pigs and mice.     

Interaction of human fibrinogen with divalent metal chlorides

Precipitation of human fibrinogen in 0.15 m NaCl occurred at pH 7.4 (Tris-HCl buffer) when ZnCl₂, CuCl₂, NiCl₂, or CoCl₂ were added beyond their respective critical concentrations. The critical concentrations were about $\text{4 × 10}{}^{\mathrm{?5}}\text{m}\text{ZnCl}{}_2\text{, 6 × 10}{}^{\mathrm{?5}}\text{m}\text{CuCl}{}_2\text{, 3 × 10}{}^{\mathrm{?4}}\text{m}\text{NiCl}{}_2\text{and}\text{1 × 10}{}^{\mathrm{?3}}\text{m}\text{CoCl}{}_2$. At pH 5.8 2-(N-morpholino)-ethane sulphonic acid buffer, the critical concentrations were found only for CuCl₂ and ZnCl₂, and were about $\text{3 × 10}{}^{\mathrm{?5}}\text{and}\text{3 × 10}{}^{\mathrm{?4}}\text{m}$, respectively. CaCl₂ and MgCl₂ were not effective up to $\text{1 × 10}{}^{\mathrm{?2}}\text{and}\text{2 × 10}{}^{\mathrm{?2}}\text{m}$ at pH 7.4 and 5.8, respectively. At pH 7.4, precipitation was better in 0.015 m NaCl than in 0.15 m NaCl for both CuCl₂ and ZnCl₂. Little or no conformational change was indicated on binding Cu²⁺ ions. The fluorescence of tryptophan was quenched only by CuCl₂, while other metal ions (ZnCl₂, NiCl₂, CoCl₂ and CaCl₂) were ineffective as quenchers.     

Effect of sulfamethoxazole-trimethoprim and sulfadoxine-primethamine against fatal pneumocystosis in SCID mice.

The effect of sulfamethoxazole-trimethoprim (S-T) and sulfadoxine-primethamine (S-P) against Pneumocystis carinii (Pc) were examined in severe combined immunodeficiency (SCID) mice which are known to be susceptible to Pc. These animals develop fatal pneumocystosis without treatment with any immunosuppressant. The results suggested that S-T and S-P were effective against both trophic and cystic forms of Pc in SCID mice.     

Glycosidically bound sialic acid levels as a predictive marker of postoperative adjuvant therapy in gastric cancer

Summary A group of 293 gastric cancer patients were examined to see if the preoperative value of glycosidically bound sialic acid is a predictor of prognosis and effectiveness of postoperative adjuvant therapy. All patients had gastrectomies and were histologically confirmed to have primary adenocarcinoma of the stomach. Some patients then received either postoperative adjuvant chemotherapy or immunochemotherapy. Patients with sialic acid levels less than 74.5 mg/dl survived significantly longer than those with sialic acid levels of 74.5 mg/dl or of 85.3 mg/dl and over. No significant differences in survival were found among patients treated by gastrectomy alone, gastrectomy plus chemotherapy and gastrectomy plus immunochemotherapy. However, patients with abnormally elevated levels of sialic acid survived significantly longer when they were treated with immunochemotherapy after gastrectomy than those treated by gastrectomy alone or with chemotherapy after gastrectomy. By using Cox's multivariate regression model, pTNM stages, postoperative adjuvant therapy (chemotherapy and immunochemotherapy) and preoperative serum levels of sialic acid were examined as prognostic variables. Postoperative therapy was a significant prognostic variable in patients with abnormally elevated levels of sialic acid. The preoperative serum level of sialic acid is a promising predictive marker of the response to postoperative adjuvant immunochemotherapy.     

The amino-terminal region of major capsid protein P3 is essential for self-assembly of single-shelled core-like particles of Rice dwarf virus

The core protein P3 of Rice dwarf virus constructs asymmetric dimers, one of which is inserted by the amino-terminal region of another P3 protein. The P3 proteins with serial amino-terminal deletions, expressed in a baculovirus system, formed particles with gradually decreasing stability. The capacity for self-assembly disappeared when 52 of the amino-terminal amino acids had been deleted. These results demonstrated that insertion of the amino-terminal arm of one P3 protein into another appears to play an important role in stabilizing the core particles.     

Abnormal angiogenesis in Foxo1 (Fkhr)-deficient mice

Members of the Foxo family, Foxo1 (Fkhr), Foxo3 (Fkhrl1), and Foxo4 (Afx), are mammalian homologs of daf-16, which influences life span and energy metabolism in Caenorhabditis elegans. Mammalian FOXO proteins also play important roles in cell cycle arrest, apoptosis, stress resistance, and energy metabolism. In this study, we generated Foxo1-deficient mice to investigate the physiological role of FOXO1. The Foxo1-deficient mice died around embryonic day 11 because of defects in the branchial arches and remarkably impaired vascular development of embryos and yolk sacs. In vitro differentiation of embryonic stem cells demonstrated that endothelial cells derived from wild-type and Foxo1-deficient embryonic stem cells were able to produce comparable numbers of colonies supported by a layer of OP9 stromal cells. Although the morphology of the endothelial cell colonies was identical in both genotypes in the absence of exogenous vascular endothelial growth factor (VEGF), Foxo1-deficient endothelial cells showed a markedly different morphological response compared with wild-type endothelial cells in the presence of exogenous VEGF. These results suggest that Foxo1 is essential to the ability of endothelial cells to respond properly to a high dose of VEGF, thereby playing a critical role in normal vascular development.     

Transcapsidation and the conserved interactions of two major structural proteins of a pair of phytoreoviruses confirm the mechanism of assembly of the outer capsid layer

The strongly conserved amino acid sequences of the P8 outer capsid proteins of Rice dwarf virus (RDV) and Rice gall dwarf virus (RGDV) and the distribution of electrostatic potential on the proteins at the interfaces between structural proteins suggested the possibility that P8-trimers of RGDV might bind to the 3-fold symmetrical axes of RDV core particles, with vertical interaction between heterologous P3 and P8 proteins and lateral binding of homologous P8 proteins, thereby allowing formation of the double-layered capsids that are characteristic of viruses that belong to the family Reoviridae. We proved this hypothesis using chimeric virus-like particles composed of the P3 core capsid protein of RDV and the P8 outer capsid protein of RGDV, which were co-expressed in a baculovirus expression system. This is the first report on the molecular biological proof of the mechanism of the assembly of the double-layered capsids with disparate icosahedral lattices.     

Evaluation of beach vegetation for conservation/rehabilitation in Tottori Prefecture,Southwest Japan

We examined 17 beaches in Tottori Prefecture to evaluate the current status of beach vegetation for conservation/rehabilitation purposes. We conducted a floristic survey and a beach vegetation status survey, and analyzed the beach environment using aerial photographs and a geographic information system. The health of the beach vegetation was evaluated by principal component analysis (PCA) of beach vegetation and environmental variables. PCA of beach vegetation variables, where axis 1 represented the scale of beach vegetation and axis 2 represented the quality of beach vegetation, resulted in four categories. PCA of beach environment variables, with axis 1 representing the synthetic component of grain/area/extension and axis 2 representing beach widths, also resulted in four categories. A beach vegetation list was determined from a floristic survey, and three conclusions were made based on this list. We first determined the priority of the beach plant species with regard to conservation. Based on their occurrence, the beach plants were divided into four types that were ordered with regard to their priority for beach plant conservation. We next focused on the occurrence of beach plants listed in the Red data book for Tottori Prefecture and reexamined the validity of the extinction risk category. Our conclusion was that this category needs to be updated. Finally, we compared the number of beach plant species of the survey site beaches with that of the Tottori Sand Dunes, where more natural conditions prevail. We found that only seven beaches equaled or surpassed the Tottori Sand Dunes in terms of the number of plant species. Based on these findings, we concluded that beaches other than the Tottori Sand Dunes are in need of conservation/rehabilitation.