Species differences of macrophage very low-density-lipoprotein (VLDL) receptor protein expression

Triglyceride-rich lipoproteins (TGRLs) and low-density-lipoprotein (LDL) cholesterol are independent risk factors for coronary artery disease. We have previously proposed that the very low-density-lipoprotein (VLDL) receptor is one of the receptors required for foam cell formation by TGRLs in human macrophages. However, the VLDL receptor proteins have not been detected in atherosclerotic lesions of several animal models. Here we showed no VLDL receptor protein was detected in mouse macrophage cell lines (Raw264.7 and J774.2) or in mouse peritoneal macrophages in vitro. Furthermore, no VLDL receptor protein was detected in macrophages in atherosclerotic lesions of chow-fed apolipoprotein E-deficient or cholesterol-fed LDL receptor-deficient mice in vivo. In contrast, macrophage VLDL receptor protein was clearly detected in human macrophages in vitro and in atherosclerotic lesions in myocardial infarction-prone Watanabe-heritable hyperlipidemic (WHHLMI) rabbits in vivo. There are species differences in the localization of VLDL receptor protein in vitro and in vivo. Since VLDL receptor is expressed on macrophages in atheromatous plaques of both rabbit and human but not in mouse models, the mechanisms of atherogenesis and/or growth of atherosclerotic lesions in mouse models may be partly different from those of humans and rabbits.     

In Vivo Function and Evolution of the Eutherian-Specific Pluripotency Marker UTF1

Embryogenesis in placental mammals is sustained by exquisite interplay between the embryo proper and placenta. UTF1 is a developmentally regulated gene expressed in both cell lineages. Here, we analyzed the consequence of loss of the UTF1 gene during mouse development. We found that homozygous UTF1 mutant newborn mice were significantly smaller than wild-type or heterozygous mutant mice, suggesting that placental insufficiency caused by the loss of UTF1 expression in extra-embryonic ectodermal cells at least in part contributed to this phenotype. We also found that the effects of loss of UTF1 expression in embryonic stem cells on their pluripotency were very subtle. Genome structure and sequence comparisons revealed that the UTF1 gene exists only in placental mammals. Our analyses of a family of genes with homology to UTF1 revealed a possible mechanism by which placental mammals have evolved the UTF1 genes.     

Influences of stearidonic acid-enriched soybean oil on the blood and organ biochemical parameters in rats

In this study, we administered various diets of stearidonic acid (SDA, 18:4n?3) soybean oil to rats and examined the subsequent blood and organ biochemical parameters. Male Wistar rats (seven rats/group, six groups total) were fed diets supplemented with a test oil for 4 weeks. Diets containing test oils were: FFC diet (fish-oil-free control diet), C diet (control group, assuming a Japanese diet), SDA25 diet (25% 18:4n?3 soybean oil in the C diet), SDA50 (50% 18:4n?3 soybean oil in the C diet), ALA diet (34% flaxseed oil in the C diet), and EPA+DHA diet (34% fish oil in the C diet). The intake of 18:4n?3 showed increased relative efficiency of 20:5n?3 accretions in serum and liver triacylglycerol and significantly decreased the serum triacylglycerol level in rats. The results suggested that the consumption of 18:4n?3 soybean oil may modify the lipid and fatty acid profiles of body fats, even when EPA and DHA derived from fish is consumed.     

Enzymatic Degradation of Colistin Isolation and Identification of α-N-Acyl α,γ-Diaminobutyric Acid and Colistin Nonapeptide

Colistin, a fatty acyl peptide antibiotic, was attacked by proteolytic enzymes such as papain, ficin and bromelain, and as degradation product, a peptide portion retaining the ring structure of colistin was liberated. In contrast, an analogous antibiotic polymyxin B showed a characteristic resistance to the catalytic activity of papain.

Colistin nonapeptide and α-N-fatty acyl α,γ-diaminobutyric acid were obtained as products from the above enzymatic hydrolyzates of colistin and their chemical and physicochemical properties were investigated.

Contrary to colistin, this colistin nonapeptide was inactive to Escherichia coli. NIHJ and to many other strains even at a concentration of 800 mcg/ml by the agar dilution method. As α-N-fatty acyl α,γ-diaminobutyric acid which is rest part of colistin was added to colistin nonapeptide, antimicrobial activity of colistin nonapeptide did not increase.     

Changes in Glycosyldiacylglycerols during Germination of Black Mung Beans (Matpe)

The physico-chemical characteristics of purified arginine kinases from prawn and swimming crab were examined. The molecular weights of prawn and swimming crab enzymes were 40,500 and 40,000, respectively. Amino acid analysis indicated that there were some differences in the contents of proline, glycine, methionine, and lysine. The other amino acid compositions of these enzymes resembled each other.

Both enzymes were stable up to 20°C when they were treated for 10 min at various temperature levels. The enzymes lost their activities at temperatures higher than 25°C. They were more stable at pH 8.0 than pH 7.0. The optimum temperature for the enzyme of prawn was about 42°C and that for swimming crab was about 40°C. The pH optima for the activity of arginine kinase of prawn in the forward and in the reverse reactions were found to be 9.0 and 6.1, respectively. For the swimming crab, the similar optimum pHs at 9.2 in the forward reaction and 5.8 in the reverse reaction were observed. Both enzymes were activated most strongly with Mg^{2 +} and Mn^{2 +} followed by Ca^{2 +}, Co^{2 +}, and Fe^{2 +}. The enzymes were not activated by Sr^{2 +}, Cu^{2 +}, or Zn^{2 +}.

The optimum molar ratio of Mg^{2 +}: ATP in the forward reaction of prawn and swimming crab was found to be 1:1, and the molar ratio of Mg^{2 +} : ADP in the reverse reaction was 4:1 in both cases. Kinetic studies indicated that dissociation constants were rather different. In the prawn, dissociation constants for arginine, ATP, AP, and ADP were 0.19,0.31, 0.67, and 0.29 mM, respectively, but in the swimming crab, they were 0.10, 0.18, 0.22, and 0.11 mM, respectively.     

Studies on the Bacterial Formation of a Peptide Antibiotic,Colistin

Colistinase, an enzyme inactivating colistin, which appeared in a fermented broth of Bacillus colistinus attending with decay of colistin production was studied. The enzyme was partially purified and also chromatographed by DEAE-cellulose column. It was a heat labile, mostly basic protein, had optimum pH at 9.0 and was active against peptide antibiotics such as colistin and polymyxin and also against casein. Bacterial proteinase, Nagarse, exhibited colistinase activity exclusively among tested proteinases and immunochemical studies revealed that colistinase was identical with bacterial proteinase Nagarse.     

Intracellular Localization and Characterization of Beef Liver Aldehyde Dehydrogenase Isozymes

Various physiological roles of mammalian aldehyde dehydrogenase had been anticipated because of its broad substrate specificity. In order to clarify roles of the enzyme and the regulation of aldehyde metabolisms in liver, the intracellular distribution and isozyme of beef liver aldehyde dehydrogenase were studied.

The presence of the mitochondrial, the microsomal and the cytoplasmic isozymes were proved by the isoelectric focusing. These isozymes were different from each other in pH-activity curve in the responces for steroid hormones and disulfiram.

It was suggested by comparing the reactivities of these isozymes for various aldehydes that particular aldehyde might be oxidized by a favorite isozyme at particular locality in the liver cells and that a share of physiological role among these isozymes is probable.     

Synthesis and Insecticidal Activity of 4-Substituted 1-Indanyl Chrysanthemates

A variety of 4-substituted 1-indanyl chrysanthemates were prepared and their insecticidal activity was tested on American cockroachs. The activity of the chrysanthemates decreased in the following order: CH₂=CHCH₂>CH₃OCH₂?CH₃CH₂?HC≡CCH₂>PhCH₂, which was similar to that of p-substituted benzyl chrysanthemates against houseflies with the exception of the propargyl group. Formulation of the quantative structure-activity relationship by the Hansch’s program indicated that Van der Waals interaction between the chemical substance and the macromolecular in vivo play an important role in the 1-indanyl chrysanthemates.