Electron flow and heme-heme interaction between cytochromes b-558, b-595 and d in a terminal oxidase of Escherichia coli

The ESR signals of the cytochromes in the Escherichia coli terminal oxidase cytochrome d complex were studied at cryogenic temperature. The intensities and g values of the rhombic high-spin signals changed when the electronic state of cytochrome d was changed from the oxidized state to the reduced or oxygen-binding or CO-binding state. These rhombic signals were therefore assigned to cytochrome b-595, which is located near cytochrome d in the oxidase complex. This assignment was supported by the finding that the Em value of the rhombic signals differed from that of cytochrome d (Hata, A. et al. (1985) Biochim. Biophys. Acta 810, 62-72). Photolysis and ligand-exchange experiments with the reduced CO complex of the oxidase were performed in the presence of oxygen at -140 degrees C. The ESR spectra of three intermediate forms trapped by controlled low temperatures were detected. These forms were designated as the oxygen-binding intermediate I (ESR-silent), oxygen-binding intermediate II (giving ESR signals at g = 6.3, 5.5 and 2.15), and oxygen-binding intermediate III (giving signals at g = 6.3, 5.5 and 6.0). From these results, electron flow in the cytochrome d complex is proposed to proceed in the order, cytochrome b-558----cytochrome b-595----cytochrome d----O2. A model of the mechanism of four-electron chemistry for oxidation of ubiquinol-8 and formation of H2O by the cytochrome d complex is presented.     

Characterization of a Chlamydia pneumoniae Strain Isolated from a 57-Year-Old Man

The isolation of Chlamydia pneumoniae, especially from elderly persons, is generally not easy. Recently, we succeeded in isolating a chlamydial strain, which was designated KKpn-15, from a 57-year-old man suffering from acute bronchitis. It was compared with well established strains of C. pneumoniae, C. trachomatis and C. psittaci, and its biological properties, such as the morphology of elementary bodies (EBs) and inclusions, and the immunochemistry of EB proteins, were investigated. Based on the results obtained in the present study, it was confirmed that the new chlamydial strain, KKpn-15, is a member of the C. pneumoniae strain and that the organisms of KKpn-15 are useful as an antigen for the serodiagnosis and epidemiology of C. pneumoniae infection.     

Reflections on the Conservation and Sustainable Use of Genetic Resources in the Deep Seabed Beyond the Limits of National Jurisdiction

Attention is increasingly being given to genetic resources in the deep seabed beyond the limits of national jurisdiction owing to their considerable potential scientific and economic value. At the same time, there are concerns that the increased demand for these genetic resources may result in their unsustainable collection or even in the extinction of species in the deep seabed. At present there is no specific legal framework governing these resources in international law. Thus, this article explores the relevant rules of international law applicable to the conservation and sustainable use of genetic resources in the deep seabed.     

Facile Method for the Preparation of 7-Methyl-8-oxoguanosines as an Immunomodulator¶

Abstract

Reaction of 9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-7-methylguaninium iodide (2a) with hydrogen peroxide in acetic acid gave the corresponding 7-methyl-8-oxoguanosine derivative (3a) in good yield. Deprotection of 3a easily gave 7-methyl-8-oxoguanosine (1), which is well-known as an immunomodulator. Substitution of acetyl group at the N-position of guanine ring accelerated the oxidation reaction of the 7-methylguaninium iodide.

     

Biochemical characterization of photosystem I complexes having different subunit compositions of fucoxanthin chlorophyll a/c-binding proteins in the diatom Chaetoceros gracilis

Photosynthesis Research - Diatoms are dominant phytoplankton in aquatic environments and have unique light-harvesting apparatus, fucoxanthin chlorophyll a/c-binding protein (FCP). Diatom...     

A transgenic apple callus showing reduced polyphenol oxidase activity and lower browning potential

Polyphenol oxidase (PPO) is responsible for enzymatic browning of apples. Apples lacking PPO activity might be useful not only for the food industry but also for studies of the metabolism of polyphenols and the function of PPO. Transgenic apple calli were prepared by using Agrobacterium tumefaciens carrying the kanamycin (KM) resistant gene and antisense PPO gene. Four KM-resistant callus lines were obtained from 356 leaf explants. Among these transgenic calli, three calli grew on the medium containing KM at the same rate as non-transgenic callus on the medium without KM. One callus line had an antisense PPO gene, in which the amount and activity of PPO were reduced to half the amount and activity in non-transgenic callus. The browning potential of this line, which was estimated by adding chlorogenic acid, was also half the browning potential of non-transgenic callus.     

Phosphatidylinositol 4-phosphate 5-kinase type I is regulated through phosphorylation response by extracellular stimuli

Phosphatidylinositol 4-phosphate 5-kinase (PIPK) catalyzes a final step in the synthesis of phosphatidylinositol 4,5-bisphosphate (PIP(2)), a lipid signaling molecule. Strict regulation of PIPK activity is thought to be essential in intact cells. Here we show that type I enzymes of PIPK (PIPKI) are phosphorylated by cyclic AMP-dependent protein kinase (PKA), and phosphorylation of PIPKI suppresses its activity. Serine 214 was found to be a major phosphorylation site of PIPK type Ialpha (PIPKIalpha) that is catalyzed by PKA. In contrast, lysophosphatidic acid-induced protein kinase C activation increased PIPKIalpha activity. Activation of PIPKIalpha was induced by dephosphorylation, which was catalyzed by an okadaic acid-sensitive phosphatase, protein phosphatase 1 (PP1). In vitro dephosphorylation of PIPKIalpha with PP1 increased PIPK activity, indicating that PP1 plays a role in lysophosphatidic acid-induced dephosphorylation of PIPKIalpha. These results strongly suggest that activity of PIPKIalpha in NIH 3T3 cells is regulated by the reversible balance between PKA-dependent phosphorylation and PP1-dependent dephosphorylation.     

Polymorphism of BF,C2, and GLO in Japanese patients with insulin-dependent diabetes mellitus: Confirmation of an increase of BF *FT

Summary The distribution of phenotypes controlled by three HLA-linked loci BF, C2, and GLO has been studied in Japanese patients with insulin-dependent diabetes mellitus (IDDM). A slight but significant higher incidence of a rare varian BF ^*FT (=^* F075) in patients was confirmed in the combined data with our previous study (Tokunaga et al. 1981 b). No significant association of C2 and GLO alleles with IDDM was found.     

Establishment, Growth kinetics, and Susceptibility to AcMNPV of Heat Tolerant Lepidop teran Cell Lines

Lepidopteran heat-tolerant(ht)cell lines have been obtained with sf-9,sf-21 and several Bombyx cells.They have a distinct karyotype,membrane lipid composition,morphology and growth kinetics from the parental cell lines.In this paper,we report the development of ht cell lines from other insect species and examination of their growth characteristics and virus susceptibility.Adaptation of cell lines sf-9,BTI-TN-5131-4(High5)and BTI-TN-MG1(MG 1)to 33℃ and 35℃ was carried out by shifting the culture temperature between 28℃ and higher temperatures by a gradual stepwise increase in temperature.The process of adaption to a higher culture temperature was accomplished over a period of 2 months.The cell lines with the temperature adaption were designated as sf9-ht33,sf9-ht35,High5-ht33,High5-ht35,MG1-ht33,MG1-ht35.These cell lines have been subcultured over 70 passages.Adaption to high temperatures was confirmed by a constant population doubling time with individual cell lines.The population doubling time of heat adapted cell lines were 1-4 h less than these of parental cell lines.Cell shapes did not show obvious change,however,the cell size of sf9-ht cells was enlarged and those of High5 and MG1 ht cells were reduced after heat adaption.When the cell lines were infected with Autographa californica nuclear polyhedrosis virus(AcMNPV)at 28℃,33℃,35℃ and 37℃,production of budded virus and occlusion bodies in each cell line was optimum at its own adapted temperature.     

Protein kinase C activity in platelets from spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY)

Calcium-activated phospholipid dependent protein kinase (protein kinase C) activity in platelets was measured in 4, 12, and 20-week-old SHR and WKY. At age 4-weeks, there was no significant difference in protein kinase C activity and systolic blood pressure between SHR and WKY. In 12 and 20-week-old SHR, both protein kinase C activity and systolic blood pressure were significantly higher than in the age-matched WKY. These results suggest that protein kinase C may be involved in the control of blood pressure in SHR and WKY.