Platelet activating factor induces cytoskeletal reorganization through Rho family pathway in THP-1 macrophages

In the process of atherosclerosis, platelet activating factor (PAF) promotes the infiltration of inflammatory cells into atherosclerotic plaque by modulating their cytoskeleton. Here, we examined whether Rho family proteins are involved in PAF-induced cytoskeletal reorganization in THP-1 macrophages. PAF stimulation rapidly induced cell elongation, accompanied by filopodia formation. The inhibition of Rho family proteins by the overexpression of Rho-GDI attenuated the PAF-mediated morphological changes. Both RhoA and Cdc42 were activated in response to PAF. Inhibition of RhoA or Cdc42 by dominant negative mutants abrogated morphological changes induced by PAF. Collectively, PAF regulates cytoarchitecture through Rho family proteins in macrophages.     

Functional analysis of the small subunit of the putative homoaconitase from Pyrococcus horikoshii in the Thermus lysine biosynthetic pathway

Previously, we described in Streptococcus mutans strain NG8 a 5-gene operon (sat) that includes ffh, the bacterial homologue of the eukaryotic signal recognition particle (SRP) protein, SR54. A mutation in ffh resulted in acid sensitivity but not loss of viability. In the present study, chemostat-grown cells of the ffh mutant were shown to possess only 26% and 39% of the parental membrane F-ATPase activity and 55% and 75% of parental glucose-phosphotransferase (PTS) activity when pH-7 and pH-5-grown cells, respectively, were assayed. Two-dimensional-gel electrophoretic analyses revealed significant differences in protein profiles between parent and ffh-mutant strains at both pH 5 and pH 7. It appears that the loss of active SRP (Ffh) function, while not lethal, results in substantial alterations in cellular physiology that includes acid tolerance.     

Flavonoids in translucent bracts of the Himalayan<Emphasis Type="Italic"> Rheum nobile</Emphasis> (Polygonaceae) as ultraviolet shields

UV-absorbing substances were isolated from the translucent bracts of Rheum nobile, which grows in the alpine zone of the eastern Himalayas. Nine kinds of the UV-absorbing substances were found by high performance liquid chromatography (HPLC) and paper chromatography (PC) surveys. All of the five major compounds are flavonoids, and were identified as quercetin 3-O-glucoside, quercetin 3-O-galactoside, quercetin 3-O-rutinoside, quercetin 3-O-arabinoside and quercetin 3-O-[6-(3-hydroxy-3-methylglutaroyl)-glucoside] by UV, ¹H and ¹³C NMR, mass spectra, and acid hydrolysis of the original glycosides, and direct PC and HPLC comparisons with authentic specimens. The four minor compounds were characterised as quercetin itself, quercetin 7-O-glycoside, kaempferol glycoside and feruloyl ester. Of those compounds, quercetin 3-O-[6-(3-hydroxy-3-methylglutaroyl)-glucoside] was found in nature for the first time. The translucent bracts of R. nobile accumulate a substantial quantity of flavonoids (3.3–5 mg per g dry material for the major compounds). Moreover, it was clarified by quantitative HPLC survey that much more of the UV-absorbing substances is present in the bracts than in rosulate leaves. Although the flavonoid compounds have been presumed to be the important UV shields in higher plants, there has been little characterisation of these compounds. In this paper, the UV-absorbing substances of the Himalayan R. nobile were characterised as flavonol glycosides based on quercetin.     

Fundamental roles of reactive oxygen species and protective mechanisms in the female reproductive system

Controlled oxidation, such as disulfide bond formation in sperm nuclei and during ovulation, plays a fundamental role in mammalian reproduction. Excess oxidation, however, causes oxidative stress, resulting in the dysfunction of the reproductive process. Antioxidation reactions that reduce the levels of reactive oxygen species are of prime importance in reproductive systems in maintaining the quality of gametes and support reproduction. While anti-oxidative enzymes, such as superoxide dismutase and peroxidase, play a central role in eliminating oxidative stress, reduction-oxidation (redox) systems, comprised of mainly glutathione and thioredoxin, function to reduce the levels of oxidized molecules. Aldo-keto reductase, using NADPH as an electron donor, detoxifies carbonyl compounds resulting from the oxidation of lipids and proteins. Thus, many antioxidative and redox enzyme genes are expressed and aggressively protect gametes and embryos in reproductive systems.     

Effect of addition of water-soluble chitin on amylose film

Amylose films blended with chitosan, which were free from additives such as acid, salt, and plasticizer, were prepared by casting mixtures of an aqueous solution of an enzymatically synthesized amylose and that of water-soluble chitin (44.1% deacetylated). The presence of a small amount of chitin (less than 10%) increased significantly the permeability of gases (N2, O2, CO2, C2H4) and improved the mechanical parameters of amylose film; particularly, the elastic modulus and elongation of the blend films were larger than those of amylose or chitin films. No antibacterial activity was observed with either amylose or water-soluble chitin films. But amylose films having a small amount of chitin showed strong antibacterial action, suggesting a morphological change in water-soluble chitin on the film surface by blending with amylose molecule. These facts suggested the presence of a molecular complex of amylose and chitosan.     

Proteomic analysis of livers of patients with primary hepatolithiasis

Primary hepatolithiasis or intrahepatic calculi (IHC), which is characterized by the formation of gallstones in the intrahepatic bile duct, is an intractable liver disease and suspected to be one of the causes of cholangiocellular carcinoma. To obtain an insight into the disease, we performed proteomic analysis of liver tissue specimens of paired affected and unaffected hepatic segments from patients with primary hepatolithiasis by two-dimensional gel electrophoresis followed by identification of proteins. For the specimens from the unaffected segments, 125 spots out of 613 spots were identified, defining 83 unique protein names. For the specimens from the affected segments, 102 spots out of 671 spots were identified, defining 74 unique protein names. To further precisely compare, we used two-dimensional fluorescence difference gel electrophoresis. Consequently we identified 12 up-regulated proteins and 21 down-regulated proteins. The up-regulated proteins contained the proteins related to liver fibrosis and to cellular oxidoreduction. The down-regulated proteins contained RAF kinase inhibitor protein, chaperonin and proteins related to principal liver function.     

Biotransformation of α-Santonin by Cell Suspension Cultures of Five Plants

Cell suspension cultures of five plants (Catharanthus roseus, Ginkgo biloba, Platycodon grandiflorum, Taxus cuspidata, Phytolacca asinosa) were employed to bioconvert the eudesmanolide compound, α-santonin. Reactions occurring were hydroxylation (C-1, C-11 and C-15), reduction of the double bond [1(2) or 3(4)], rearrangment of the eudesmanolide skeleton to a guaianolide skeleton and lactone-ring hydrolysis. Four new compounds were identified.