Eicosapentaenoic acid abolishes the proatherogenic effects of cholesterol: Effects on migration of bovine smooth muscle and endothelial cells in vitro

It is well known that vascular endothelial cell (EC) migration plays a major role in regeneration of the injured endothelium and also that smooth muscle cell (SMC) migration is the important step for atheromatous plaque formation. In the present study, we investigated the effects of cholesterol and eicosapentaenoic acid (EPA) on bovine carotid artery EC and SMC migration using the modified Boyden chamber technique. The migration activity of the cholesterol-enriched ECs loaded with cholesterol-rich liposomes was significantly suppressed, whereas that of the cholesterol-enriched SMCs was enhanced. Next, we examined the effects of EPA pretreatment on the migration of both cell types. When ECs and SMCs were treated with EPA (5 μg/ml) for 2 days, the EPA content increased from 0.55 ± 0.04% to 11.72 ± 0.19% and 1.22 ± 0.09% to 9.69 ± 0.07% in cellular phospholipids, respectively. Although pretreatment of the ECs with EPA caused a significant increase in serum-induced cell migration, pretreatment of SMCs had no effect. if both cell types were concomitantly pretreated with EPA and cholesterol-rich liposomes, EPA abolished the effects of cholesterol on the migration of both cell types, but did not affect the content of cholesterol in both cells. These data indicate the possibility that EPA counteracts the atherogenic effect of cholesterol on EC and SMC migration.     

Chloroplast DNA Variation in the genusSesamum

It is widely approved that comparing restriction profiles and maps of chloroplast DMA provides valuable information concerning inter-and/or intra-specific relationships among plant species. Such chloroplast DNA analysis was applied to species and strains inSesamum which is a genus of approximately 38 species and contains a large number of strains of the cultivated sesame,S. Indlcum. Our chloroplast DNA investigations of 22 species and strains showed that; (i) among four species (S. capense, S. radiatum, S. schinzianum andS. indicum), the chloroplast genome ofS. capense was most distantly related to that of the cultivated species,S. indicum, (ii) chloroplast DNA polymorphism was also recognized among eight cultivated stralns collected from various regions in the tropical zone, but not among eight different varieties grown in the temperate zone, and (iii) the chloroplast DNA alterations observed could be attributed to the site gains or losses with the exception of the alterartion detected within the inverted repeat sequences inS. capense chloroplast DNA. These results demonstrate the presence of chloroplast genome diversity amongSesamum species and strains, suggesting the usefulness of chloroplast DNA analysis for elucidating the species relationships in the genusSesamum and the origin and evolutionary process of the cultivated sesame species. The present paper is based on the contribution which was read in a symposium entitled “Organellar DNA Variations in Higher Plants and Their Taxonomic Significance”, at the 50th Annual Meeting of the Botanical Society of Japan in Shizuoka on October 2, 1990, under the auspices of the Japan Society of Plant Taxonomists.     

Evidence for cis-trans isomerization of a double bond in the fatty acids of the psychrophilic bacterium Vibrio sp. strain ABE-1.

Vibrio sp. strain ABE-1 was grown in a medium that contained as its stable isotope tracer either [2,2-2H2]cis-9-hexadecenoic or [2,2-2H2]trans-9-hexadecenoic acid. Gas chromatographic-mass spectrometric analysis of the cis-9-hexadecenoic and trans-9-hexadecenoic acid fractions from the cells revealed the formation of an intracellularly isomerized 2,2-2H2-fatty acid which differed from the tracer only in the geometrical configuration of the double bond. This observation shows that cis-trans isomerization without a shift in double-bond position between these two geometric hexadecenoic acid isomers can occur in the cells.     

Seroepidemiological Survey of Bartonella (Rochalimaea) henselae in Domestic Cats in Japan

A total of 199 domestic cat serum samples from 3 geographical areas (northeastern, central and southwestern) of Japan collected between 1992 to 1994 were examined for serum antibody against Bartonella henselae using an immunofluorescent assay. The antibody prevalence was 15.1% (30/199). A significant difference in the prevalence of B. henselae antibody was observed between the northeastern area (6.3%:3/48) and the central area (22.0%: 13/59) in Japan. There was no significant difference between the average age of seropositive cats (4.39 ±3.26 years) and that of seronegative cats (4.03 ±3.84 years), and also between the frequency of seropositive male cats (16.5%: 15/91) and that of seropositive female cats (11.8%:9/76). This is the first report of B. henselae antibodies in cats in Japan.     

Thrombopoietin stimulates proliferation and megakaryocytic differentiation of mouse pro-B cell line BF-TE22

We have isolated and characterized a thrombopoietin (TPO)-dependent BF-TE22 cell line endogenously expressing murine Mpl, which is a subclone of murine pro-B Ba/F3 cells. TPO stimulated the proliferation of BF-TE22 cells in a dose-dependent manner, and also induced the expression of megakaryocyte lineage-specific AP-51 and CD61 cell surface antigens. The results indicate that the murine Mpl on BF-TE22 cells can transmit both proliferation and megakaryocyte lineage-specific differentiation signals to cells. Furthermore, it was shown that IL-3 inhibits the TPO-induced differentiation signals of BF-TE22 cells. These results suggest that the signals mediated by IL-3 predominate over those of TPO in BF-TE22 cells. Thus, BF-TE22 cells will be useful for the biological and biochemical studies of the TPO-Mpl signal transduction mechanism. This revised version was published online in June 2006 with corrections to the Cover Date.     

Phylogenetic Position of the Phacotaceae Within the Chlamydophyceae as Revealed by Analysis of 18S rDNA and rbcL Sequences

Four genera of the Phacotaceae (Phacotus, Pteromonas, Wislouchiella, Dysmorphococcus), a family of loricated green algal flagellates within the Volvocales, were investigated by means of transmission electron microscopy and analysis of the nuclear encoded small-subunit ribosomal RNA (18S rRNA) genes and the plastid-encoded rbcL genes. Additionally, the 18S rDNA of Haematococcus pluvialis and the rbcL sequences of Chlorogonium elongatum, C. euchlorum, Dunaliella parva, Chloromonas serbinowii, Chlamydomonas radiata, and C. tetragama were determined. Analysis of ultrastructural data justified the separation of the Phacotaceae into two groups. Phacotus, Pteromonas, and Wislouchiella generally shared the following characters: egg-shaped protoplasts, a single pyrenoid with planar thylakoid double-lamellae, three-layered lorica, flagellar channels as part of the central lorica layer, mitochondria located in the central cytoplasm, lorica development that occurs in mucilaginous zoosporangia that are to be lysed, and no acid-resistant cell walls. Dysmorphococcus was clearly different in each of the characters mentioned. Direct comparison of sequences of Phacotus lenticularis, Pteromonas sp., Pteromonas protracta, and Wislouchiella planctonica revealed DNA sequence homologies of ≥98.0% within the 18S gene and 93.9% within the rbcL gene. D. globosus was quite different from these species, with a maximum of 92.9% homology in the 18S rRNA and ≤86.6% in the rbcL gene. It showed major similarities to the 18S rDNA of Dunaliella salina, with 95.3%, and to the rbcL sequence of Chlamydomonas tetragama, with 90.3% sequence homology. Additionally, the Phacotaceae sensu stricto exclusively shared 10 (rbcL: 4) characters which were present neither in other Chlamydomonadales nor in Dysmorphococcus globosus. Different phylogenetic analysis methods confirmed the hypothesis that the Phacotaceae are polyphyletic. The Phacotaceae sensu stricto form a stable cluster with affinities to the Dunaliellaes and possibly Haematococcus pluvialis. Dysmorphococcus globosus represented an independent lineage that is possibly related to Chlamydomonas moewusii and C. tetragama. Received: 9 June 1997 / Accepted: 17 October 1997     

The Effect of thecrp Genotypes on the Transformation Efficiency in Escherichia coli

We have found that a significant difference exists in transformationefficiency between the crp⁺/crp^– isogenic pair of strainsof Escherichia coli, with the efficiency being much higher incrp^– than in crp⁺. The ratio of transformation efficiencybetween crp⁺ and crp^– strains depends very little on theplasmid size. This observation suggests that the differenceof the transformation efficiency is due to mechanisms otherthan a crp-regulated endonuclease. The crp gene is one of thefirst specific genes that have been shown to affect transformationefficiency.     

Binding of magnesium to myosin subfragment-1 ATPase

Tyr 180 of chicken breast muscle alkali light chain A1 was nitrated with tetranitromethane. The nitroA1 was incorporated into chicken breast muscle subfragment-1 (S-1) by exchange with the intrinsic alkali light chain. In the presence of adenylylimidodiphosphate (AMPPNP) or ADP, the S-1 containing nitroA1 showed a difference visible absorption spectrum by Mg2+ or Ca2+. The difference spectrum has a trough around 435 nm, indicating a blue shift of the absorption spectrum due to the nitrophenol chromophore of the modified A1. The plot of delta A at 435 nm versus concentration of free Mg2+ fitted a single binding curve, independent of the total concentration of AMPPNP. These results reveal that free Mg2+ binds to the active site of S-1 ATPase, but not as Mg-AMPPNP complex. The dissociation constants of magnesium from S-1 complex were different with the two nucleotides and were 1.25 X 10(-8) M and 1.24 X 10(-7) with AMPPNP and ADP, respectively. The difference spectrum was also obtained in the presence of ATP. The delta epsilon value after adding ATP changed with the ATPase reaction. The steady state rate of S-1 ATPase was measured at various concentrations of free Mg2+. The dissociation constant of magnesium from the steady state complex, EPADP(a), was estimated as 6 X 10(-8) M. These results suggest that the affinity of magnesium at the active site of ATPase changes with the intermediate states of ATPase reaction. The affinity of calcium was lower than that of magnesium.     

Structure of rice ferricytochrome c at 2.0 A resolution

The crystal structure of ferricytochrome c from rice embryos has been solved by X-ray diffraction to a resolution of 2.0 A, applying a single isomorphous replacement method with anomalous scattering effects. The initial molecular model was built on a graphics display system and was refined by the Hendrickson and Konnert method. The R factor was reduced to 0.25. Rice cytochrome c consists of III amino acid residues. In comparison with animal cytochromes c, the peptide chain extends for eight residues at the N-terminal end, which is characteristic for plant cytochromes c. These additional residues display a collagen-like conformation and an irregular reverse turn, and are located around the C-terminal alpha-helix on the surface or the rear side of the molecule. Two hydrogen bonds between the carbonyl oxygen of the N-terminal acetyl group and O eta of Tyr65, and between the peptide carbonyl oxygen of Pro-1 and O epsilon 1 of Gln89, are involved in holding these eight residues on the molecular surface, where Tyr65 and Gln89 are invariant in plant cytochromes c. Except for the extra eight residues, the main-chain conformations of both rice and tuna cytochromes c are essentially identical, though small local conformational differences are found at residues 24, 25, 56 and 57.     

Observations on microbial percent respiration values in arctic and subarctic marine waters and sediments

Percent respiration was measured in over 1,100 arctic and subarctic marine water and sediment samples using¹⁴C-labeled glucose and glutamate. These measurements were made at different times of the year in 4 regions. Percent respiration values were typically lower in regions where the waters of large rivers mixed with seawater. They were also lower in sediments and in waters collected near the bottom than in surface waters. They were higher in winter arctic waters than water samples collected in the summer; however, a similar seasonal trend was not observed in subarctic waters. There were a number of studies in which there were significant positive rank correlations between percent respiration and salinity and between percent respiration and temperature. From what is known about the range of temperature and salinity encountered in samples collected during these studies and the results of temperature and salinity effects experiments, it was concluded that changes in these 2 variables did not explain the variation observed in percent respiration. Correlations between percent respiration and the inorganic nutrients PO₄ ^–3, NH₄ ⁺ and NO₃ ^– showed that of the 3 variables, only NO₃ ^– showed relatively high correlations with all the same sign. From this it was concluded that there may be situations in which NO₃ ^– levels may influence percent respiration in nearshore marine waters. It is also likely that qualitative characteristics of the available organic nutrients may also influence percent respiration levels. Although no organic nutrient data is available for statistical analysis, the patterns of percent respiration near river plumes and the relatively strong negative correlation often observed between uptake rates (heterotrophic activity) and percent respiration suggests that organic nutrients may be a factor in controlling percent respiration. It is suggested that there are situations in which percent respiration measurements may be used to document stress in natural microbial populations due to nutrient deficiencies.