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Background Dotinurad is a selective urate reabsorption inhibitor (SURI), which selectively inhibits URAT1 to lower serum uric acid levels in patients with hyperuricemia. Herein, the effects of dotinurad were compared among patient groups with different stages of renal dysfunction. Methods Patient data from four clinical trials were pooled and divided into four groups according to the stage of renal dysfunction to compare the effects of dotinurad at different stages. The grouping (stages G1–G3b) was based on the estimated glomerular filtration rate (eGFR) of the patients. In addition, patient data from a long-term study (34 or 58 weeks) were evaluated in the same manner. Results In the pooled analysis, the percentage of patients achieving a serum uric acid level of ≤ 6.0 mg/dL was 64.7–100.0% at a dose of 2 or 4 mg. In the long-term analysis, the percentage of patients achieving a serum uric acid level of ≤ 6.0 mg/dL was 60.0–100.0% at a dose of 2 or 4 mg. Although the outcomes in stage G3b were worse due to higher baseline serum uric acid levels, satisfactory outcomes were observed in all stages. Even in stages G3a and G3b, when renal function declined, the eGFR remained constant throughout the dose period. Conclusion The efficacy of dotinurad was confirmed in hyperuricemic patients with normal renal function (stage G1) and mild to moderate renal dysfunction (stage G2–G3b). Dotinurad was found to be effective in the treatment of hyperuricemia in patients with mild to moderate renal dysfunction.

Introduction Gout is an inflammatory disease triggered by deposition of urate crystals secondary to longstanding hyperuricemia, and its management implies both the treatment of flares and management of hyperuricemia. Dotinurad is a selective urate reabsorption inhibitor (SURI), potently inhibits urate transporter 1 in the apical surface of renal proximal tubular cells, and has been approved for the treatment of gout and hyperuricemia in Japan. Areas covered This overview of dotinurad covers nonclinical and clinical pharmacology studies in special populations and its efficacy and safety in Japanese hyperuricemic patients with and without gout. Expert opinion Dotinurad, as an SURI, is expected to inhibit urate reabsorption more effectively than conventional urate-lowering agents. It is noninferior to benzbromarone or febuxostat in reducing serum urate levels in hyperuricemic patients with or without gout. Its efficacy is not attenuated in patients with mild to moderate renal impairment or with hepatic impairment. At a maintenance dose of 2 or 4 mg once daily, most patients achieved the target serum urate level of ≤6 mg/dL in a long-term study. No findings that raised safety concerns, including liver injury, were identified. Dotinurad is expected to be a new therapeutic option in hyperuricemic patients with and without gout.

Pressed sake cake, a by-product of sake brewing, is a rich dietary source of folates, which are important vitamins for humans. However, considerable losses of folates occur during storage and cooking. We have previously reported that Km67, the house sake yeast strain of Kiku-masamune sake brewery, can accumulate high folate levels. In this study, we found that the folate content of pressed sake cakes produced with Km67 remained at approximately their maximum level after the fermentation activity stopped. To elucidate the mechanisms of high folate accumulation in Km67, we analyzed the expression of 23 folate-metabolizing genes. The expression of ABZ1 and FOL3 was almost always higher in Km67 than in Kyokai no. 701 yeast (K701), which suggested that enhanced expression of the genes involved in folate biosynthesis was a mechanism of high folate accumulation in Km67. We found that the folates of Km67 pressed sake cakes were quantitatively stable at 4°C under refrigerated storage conditions. In addition, the homocysteine content of Km67 pressed sake cakes was almost always higher than that of K701 pressed sake cakes. This result suggests that a reason for high folate accumulation in Km67 yeast is the need to reduce the intracellular concentration of homocysteine. Our results provide biologically meaningful information on folate metabolism in yeast.

Folates are important vitamins in human nutrition. Pressed sake cake, a brewing by-product of sake, is a rich dietary source of folates derived from sake yeast (Saccharomyces cerevisiae). The National Research Institute of Brewing investigated 106 samples of pressed sake cake and revealed that three samples containing large amounts of folates were produced by Km67 yeast derived from the house sake yeast strain of Kiku-Masamune sake brewery. In this study, we performed sake brewing tests using Km67 and Kyokai no. 7 group strains and confirmed that Km67 yeast contributed to the production of pressed sake cake containing large amounts of folates. To elucidate the mechanisms of high folate accumulation in Km67, we performed whole-genome sequence analysis in Km67 and then screened 10 folate-metabolizing genes showing different sequences in Km67 and K7 strains. By folate analysis of each gene-disrupted strain derived from strain BY4743, we also selected four genes having significant effects on folate content in yeast from 10 candidate genes. Folate analysis of gene-disrupted yeast strains complemented with either Km67-type genes or K7-type genes revealed that the Km67-type HMT1 gene was related to high folate accumulation not only in laboratory yeast but also in sake yeast. In this gene, Leu63Phe was present in the methyltransferase motif I of Hmt1p, which was essential for the methyltransferase activity of Hmt1p. Our results and previous reports suggested that the methyltransferase activity of Km67-Hmt1p was higher than that of K7-Hmt1p, leading to enhanced production and high accumulation of folates in Km67 yeast.

Background: Hyperuricemia is a risk factor for the development of hypertension and is comorbid in many hypertensive patients. According to Japanese hypertension management guidelines published in 2019, a target serum uric acid level of ≤6.0 mg/dL is recommended in hypertensive patients with gout or asymptomatic hyperuricemia. Dotinurad is a novel uric acid-lowering drug classified as a selective urate reabsorption inhibitor. A pooled analysis was performed on the uric acid-lowering effect of dotinurad in 222 hypertensive patients with gout or asymptomatic hyperuricemia in four clinical trials (NCT02344862, NCT02416167, NCT03100318, NCT03372200). Moreover, we analyzed the long-term uric acid-lowering effect of dotinurad in 154 hypertensive patients with gout or asymptomatic hyperuricemia (NCT03006445).Results: In the pooled analysis, the percent change in the decrease of serum uric acid with the use of dotinurad was 42.17 ± 12.42% at a dose of 2 mg and 60.42 ± 8.03% at a dose of 4 mg; the percentage of patients who achieved a serum uric acid level of ≤6.0 mg/dL was 82.8% and 100.0%. The long-term uric acid-lowering effect of dotinurad showed almost the same results. In this study, the concomitant use of diuretics or angiotensin II receptor blockers affected the uric acid-lowering effect of dotinurad at only a dose of 2 mg in the pooled analysis.Conclusions: In the pooled analysis, dotinurad lowered serum uric acid levels. Dotinurad has an achievement rate of over 80% for serum uric acid level of ≤6.0 mg/dL in both analyses, and will be clinically useful for the management of hyperuricemic states in hypertensive patients.

In traditional kimoto-type sake production, cells of Saccharomyces cerevisiae sake yeast are grown in a starter mash generated by lactate fermentation by lactic acid bacteria (LAB) such as Leuconostoc mesenteroides and Lactobacillus sakei. However, the microbial interactions between sake yeast and kimoto LAB have not been well analyzed. Since the formation of a prion-like element (designated [GAR+]) in yeast cells is promoted by bacteria, we here examined the associated phenotype (i.e., increased glucosamine resistance) in sake yeast strains K701 (a representative sake strain) and Km67 (a strain isolated from kimoto-type sake mash). Approximately 0.5% of K701 and Km67 cells, as well as 0.2% of laboratory strain X2180 cells, exhibited increased glucosamine resistance under pure culture conditions, and the frequency of this metabolic switching was further enhanced by coculture with kimoto LAB. The LAB-promoted emergence of the glucosamine-resistant cells was the most prominent in Km67, suggesting that this strain possesses an advanced mechanism for response to LAB. While the glucosamine-resistant clones of X2180 and K701 exhibited lower rates of alcoholic fermentation under high-glucose conditions than did the respective naive strains, glucosamine resistance did not severely affect alcoholic fermentation in Km67. The population of dead cells after alcoholic fermentation was decreased in the glucosamine-resistant clones of X2180, K701, and Km67. These results suggested that the formation of [GAR+] in Km67 may be beneficial in kimoto-type sake making, since [GAR+] may increase cell viability in the sake starter mash without impairing alcoholic fermentation performance.

In traditional kimoto-type sake production, cells of Saccharomyces cerevisiae sake yeast are grown in a starter mash generated by lactate fermentation by lactic acid bacteria (LAB) such as Leuconostoc mesenteroides and Lactobacillus sakei. However, the microbial interactions between sake yeast and kimoto LAB have not been well analyzed. Since the formation of a prion-like element (designated [GAR

Isoamyl acetate is an important flavor compound in sake. However, production of isoamyl acetate by Saccharomyces cerevisiae is significantly reduced during sake brewing with rice that has a high polishing ratio, because unsaturated fatty acids derived from the outer layer of rice repress the expression of ATF1, which encodes an alcohol acetyl transferase. Yeast mutants capable of relieving this repression would allow the brewing of rice with high polishing ratios, improving the diversity of taste and flavor of sake. Atf1p is also believed to contribute to biological membrane homeostasis. We isolated four yeast mutants (hia1, hia2, hia4, and hia6) that have high isoamyl acetate productivity and are resistant to aureobasidin A, an inhibitor of sphingolipid biosynthesis. The isoamyl acetate content of sake brewed with the hia1 mutant was 2.6 times higher than that of the parental strain. ATF1 was expressed constitutively in the hia1 mutant during brewing and remained derepressed upon the addition of unsaturated fatty acids. Whole-genome sequence analysis of the hia mutants revealed a homozygous nonsense mutation (Ser706*) in MGA2 in all four mutants. Mga2p, an endoplasmic reticulum (ER) membrane protein, regulates ATF1 transcription. The expression of ATF1 was elevated in BY4743 Δmga2 cells complemented with MGA2 (Ser706*), and this was not completely inhibited by the addition of unsaturated fatty acids. These results indicate that a nonsense mutation in MGA2 induces high levels of isoamyl acetate production in S. cerevisiae. This finding has applications for brewing sake with high levels of isoamyl acetate.

T-2307, an arylamidine compound, has been previously reported to have broad-spectrum in vitro and in vivo antifungal activities against clinically significant pathogens, including Candida species, Cryptococcus neoformans , and Aspergillus species, and is now undergoing clinical trials. Here we investigated the mechanism of action of T-2307 using yeast cells and mitochondria isolated from yeast and rat liver. Nonfermentative growth of Candida albicans and Saccharomyces cerevisiae in glycerol medium, in which yeasts relied on mitochondrial respiratory function, was inhibited at 0.001 to 0.002 μg/ml (0.002 to 0.004 μM) of T-2307. However, fermentative growth in dextrose medium was not inhibited by T-2307. Microscopic examination using Mitotracker fluorescent dye, a cell-permeant mitochondrion-specific probe, demonstrated that T-2307 impaired the mitochondrial function of C. albicans and S. cerevisiae at concentrations near the MIC in glycerol medium. T-2307 collapsed the mitochondrial membrane potential in mitochondria isolated from S. cerevisiae at 20 μM. On the other hand, in isolated rat liver mitochondria, T-2307 did not have any effect on the mitochondrial membrane potential at 10 mM. Moreover, T-2307 had little inhibitory and stimulatory effect on mitochondrial respiration in rat liver mitochondria. In conclusion, T-2307 selectively disrupted yeast mitochondrial function, and it was also demonstrated that the fungal mitochondrion is an attractive antifungal target.

Aqueous 4-methylphenol solution with bromide ion was treated with hypochlorite at 20°C under various experimental conditions. Changes in the composition of the halogenated products in water were determined by gas chromatographic (GC) and GC-mass spectrometric (GC/MS) analyses of diethyl ether extracts. 4-Methylphenol was shown to produce a variety of halogenated compounds, including polybrominated/chlorinated phenoxyphenols (Br/Cl-predioxins), having one to four halogen atoms, as by-products in the chlorine-treated water. Production of these predioxins is dependent on the number of equivalent of chlorine atoms per mole of compound and on the reaction pH. These results suggest that the chlorine treatment of water contaminated with 4-methylphenol and bromide ion leads to the formation of Br/Cl-predioxins, which are precursor of the highly toxic halogenated dibenzo-p-dioxins.

In a previous study, we developed a novel cationic lipid consisting of polyamidoamine dendron of third generation and two dodecyl chains, designated as DL-G3, which in combination with a fusogenic lipid dioleoylphosphatidylethanolamine (DOPE) achieves efficient transfection of CV1 cells by synergetic action of the proton sponge effect and membrane fusion. This study examines the effect of serum on the transfection activity of the DL-G3-DOPE-plasmid DNA lipoplexes. The transfection activity of a lipoplex with a composition optimized in the absence of serum decreased markedly in the presence of serum. However, the lipoplexes that induce efficient transfection in the presence of serum were obtainable by controlling the charge ratio of the primary amine of the DL-G3 to the phosphate group (N/P ratio) and DOPE content. The complex, which exhibited the highest transfection activity in the presence of serum, has a lower N/P ratio and higher DOPE content than that optimized in the absence of serum. Whereas disintegration of these complexes was induced by addition of heparin, which is a polysaccharide with negatively charged groups, the complex that retained transfection activity in the presence of serum required more negative charges of heparin for complex disintegration. That result implies its higher stability against negatively charged serum proteins. Comparison of the serum-resistant complex with some commercially available transfection reagents, such as Lipofectamine and SuperFect, indicates that the DL-G3 complex achieved more efficient transfection of these cells in the presence of serum.

Sake yeasts take up gamma-aminobutyric acid (GABA) derived from rice-koji in the primary stage of sake brewing. The GABA content in sake brewed with the UGA1 disruptant, which lacked GABA transaminase, was higher than that brewed with the wild-type strain K701. The UGA1 disruptant derived from sake yeast could not grow on a medium with GABA as the sole nitrogen source. We have isolated the sake yeast mutants of K701 that were unable to grow on a medium containing GABA as the sole nitrogen source. The growth defect of GAB7-1 and GAB7-2 mutants on GABA plates was complemented by UGA1, which encodes GABA transaminase, and UGA2, which encodes succinic semialdehyde dehydrogenase (SSADH), respectively. DNA sequence analysis revealed that GAB7-1 had a homozygous nonsense mutation in UGA1 and GAB7-2 had a heterozygous mutation (G247D) in UGA2. The GABA transaminase activity of GAB7-1 and the SSADH activity of GAB7-2 were markedly lower than those of K701. These GAB mutants displayed a higher intracellular GABA content. The GABA contents in sake brewed with the mutants GAB7-1 and GAB7-2 were 2.0 and 2.1 times higher, respectively, than that brewed with the wild-type strain K701. These results suggest that the reduced function of the GABA utilization pathway increases the GABA content in sake.

Resonance Raman spectra of cytochrome c oxidase in intact whole mitochondria were selectively observed. The Raman bands observed at 576, 517, and 369 cm-1 for the carbon monoxide-bound state were assigned to the δFe–C–O, νFe–CO, and δFe–C–O modes, respectively, of heme a3-CO complex based on the 13C18O isotopic frequency shifts. These frequencies are essentially the same as those observed for solubilized cytochrome c oxidase, which implies that the environmental structure of the dioxygen reducing site in the solubilized state is not very much altered. It is likely that the dioxygen reducing reaction studied so far for solubilized enzyme is also valid for intact whole mitochondria.

It is well known that sake yeast has a high tolerance for ethanol, as compared to baker's yeast. To investigate the relationship between the ethanol tolerance of sake yeast and the palmitoyl-CoA pool for protein modification, the growth of yeast cells with depletion of the palmitoyl-CoA pool was monitored in the presence of ethanol. The overexpression of SNC1 was used to achieve the depletion of the palmitoyl-CoA pool, because the loss of Snc palmitoylation does not affect the general growth characteristics of yeast and does not interfere with the secretory processes (Couve, A. et al ., Proc. Natl. Acad. Sci. USA, 92, 5987–5991 (1995)). Although the sake yeast UT-1 exhibited much better growth in the presence of ethanol than laboratory strains, the overexpression of Snc1 was accompanied by sparse growth with increasing ethanol concentration. Exogenous palmitic acid rescued the poor growth caused by Snc1 overexpression, and the overexpression of Snc1 ser95 (which could not palmitoylated) had no effect on the growth characteristics of strain UT-1, suggesting that the poor growth with Snc1 overexpression was due to an overall increase in proteins in the unpalmitoylated form. To ascertain that fatty acid activation has a distinct role in the growth of yeast in the presence of ethanol, FAA genes encoding long chain acyl-CoA synthetases were overexpressed in combination with snc1 overexpression. Interestingly, the growth defect caused by snc1 overexpression was rescued by the overexpression of FAA4 , but not of FAA1 , which plays a predominant role in laboratory strains. On the contrary, disruption of faa1 led to faster growth in the presence of ethanol. These results suggest that Faa1p and Faa4p play reciprocal roles in regulating protein modification during growth in the presence of ethanol, since Faa1p and Faa4p both function to incorporate palmitic acid into phospholipids and neutral lipids. Moreover, Northern hybridization analysis revealed that faa1 mRNA was expressed strongly in a laboratory strain, and weakly in the sake yeast strain K-7 which exhibited good growth in the presence of ethanol. The combination of the disruption of faa1 and exogenously supplied palmitic acid was highly effective for growth in the presence of ethanol even under the normal snc1 expression level, implying that activation of exogenous palmitic acid by Faa4p is of particular importance in growth in ethanol.

In the supernatant of sokujo-moto, a high level of acid carboxypeptidase (ACP) activity and a large amount of peptides were observed, however, the amount of free amino acids liberated was small. In order to determine why these peptides were not hydrolyzed to any significant degree by the ACP, the properties of the peptides in sokujo-moto were investigated in this study. Peptides were fractionated from sokujo-moto by ion exchange column chromatography. ACP purified from rice-koji (rice overgrown with Aspergillus oryzae) was allowed to react with the peptides, and it was found that they were not hydrolyzed to any significant degree by the enzyme. Gel filtration chromatography was performed to ascertain the molecular size distribution of the peptides in sokujo-moto, and it was revealed that they were of low molecular sizes; molecular size: mainly in the range of 200-400, and chain length: 2-3. ACP purified from rice-koji was also allowed to react with various synthetic peptides, and it was found that ACP of rice-koji could not rapidly hydrolyze low-molecular-size peptides, such as dipeptides or tripeptides. Acid protease (AP) purified from rice-koji released peptides of molecular sizes mainly in the range of 300-600 or above from rice protein under acidic conditions (pH 3.6; the pH of sokujomoto). When AP and ACP were allowed to act at the same time on rice protein, mainly low-molecular-size peptides (molecular sizes mainly in the range of 200-400) were produced. From these results, it was estimated that AP released peptides with molecular sizes mainly in the range of 300-600 or above from rice protein and ACP degraded the relatively higher molecular size peptides among them to lower molecular size peptides; consequently only low-molecular-size peptides with molecular sizes mainly in the range of 200-400 were released in the supernatant of sokujo-moto.

It was found that a large amount of TCA (trichloroacetic acid)-insoluble peptides were liberated into the supernatant of kimoto on the 7th-10th day of mashing. These TCA-insoluble peptides had five polypeptide groups (12, 21, 31, 38, and 55 kDa) on SDS-PAGE (SDS-polyacrylamide gel electrophoresis), and a large amount of high molecular weight peptides, higher than 10,000, were observed upon gel filtration chromatography using TSKgel G2000swxl (Tosoh Co.). Four of these peptides (12, 21, 31, and 38 kDa on SDS-PAGE) appeared specifically in kimoto, and were not detected at all either in sokujo-moto or in the main mash for sake brewing. These TCA-insoluble peptides were fractionated from the supernatant of kimoto on the 9th day, and it was revealed that free amino acids were produced abundantly from them in the presence of the enzyme of rice-koji. Therefore, it was assumed that the peptides are related to the abundant production of free amino acids in kimoto. For the liberation of these TCA-insoluble peptides from rice protein, the enzyme of rice-koji was indispensable. The enzyme liberating the TCA-insoluble peptides from rice protein was purified from rice-koji, and was presumed to be identical with acid protease (AP) of rice-koji. The presence of a high concentration of glucose (higher than 20%) was also indispensable for the liberation of the TCA-insoluble peptides. Furthermore, it was revealed that the peptides were liberated from rice protein under a limited pH of around 4.5.

Lactic acid bacteria (LAB) in fermented foods have attracted considerable attention recently as treatment options for allergic diseases, the incidence of which has been increasing worldwide. Five strains of LAB isolated from kimoto, the traditional seed mash used for brewing sake, were screened for the ability to suppress IgE-mediated hypersensitivity reaction. Leuconostoc mesenteroides and Lactobacillus sakei, the normal microflora in kimoto, significantly suppressed the reaction, but the contaminant Lactobacillus curvatus did not. Next, we examined the effect of L. sakei LK-117 on atopic dermatitis in the NC/Nga mouse model. LK-117 supplementation significantly reduced the development of atopic dermatitis-like skin lesions in a manner independent of the IgE plasma levels. In the in vitro intestinal model constructed using the human intestinal epithelial cell line Caco-2 and murine macrophage cell line RAW 264.7, treatment with L. sakei LK-117, but not L. curvatus, significantly upregulated TNF-α production from RAW264.7 cells. This result indicated that L. sakei on the apical side affected the macrophages on the basolateral side, and this organism may have the ability to improve allergy symptoms mediated by the intestinal immune system.

Many studies have investigated the immunostimulatory effects of bacteria, such as the anti-allergic effects of lactic acid bacteria (LAB) and LAB-fermented milk. Importantly, these anti-allergic effects have been observed for both viable and nonviable bacteria. However, there are no reported immunological effects of LAB isolated from kimoto, the traditional yeast starter culture used for brewing sake, which also involves spontaneous lactate fermentation. In this study, we determined whether the Leuconostoc mesenteroides and Lactobacillus sakei bacterial strains obtained from kimoto affected the production of interleukin-12 (IL-12), an inducer of the T-helper type-1 immune response. By incubating autoclaved bacteria with J774.1 macrophage-like cells, we found that L. sakei LK-117 induced a sustained increase in IL-12p40 production. The IL-12-inducing ability of LK-117 was unaffected by anti-TLR2 neutralization and was entirely inhibited when the LK-117 cells were treated with RNase. When LK-117 cells were treated with M-1, an N-acetylmuramidase, at varying concentrations and for different periods of time, the ability of the bacteria to induce IL-12 decreased quickly. Although an active fraction could be prepared by chromatography from the soluble products of enzymolysis, the fraction's induction ability was

Three kinds of head-tail-type block copolymers composed of polyamidoamine (PAMAM) dendron heads and poly(L-lysine) (PLL) tail blocks (PAMAM dendron-PLL), having PAMAM dendrons with different generations (G2.5-PLL, G3.5-PLL and G4.5-PLL) were synthesized. Some of the dendron heads were located at polyplex surface, and G2.5-PLL and G3.5-PLL could form small polyplexes (less than 150 nm in size). G2.5-PLL and G3.5-PLL polyplexes were taken up into the cells more effectively. PAMAM dendron-PLL that had a larger dendron head could show a more-effective buffering effect. The in vitro performance of the PAMAM dendron-PLL polyplexes was controlled by the balance of cellular uptake and endosomal escape by a buffering effect.

It was found that the peptide content of the main mash in the sake brewing process, seeded with kimoto, was higher than in that seeded with sokujo-moto, although the peptide content in kimoto was lower than in sokujo-moto. We investigated the underlying reasons. As a result, we found that the high concentration of free amino acids originating from kimoto decreased the peptide uptake ability of yeast cells in the main mash seeded with kimoto.

Recently, we developed a new type of cationic lipid that consists of an amine-terminated poly(amidoamine) dendron and two long alkyl groups. These dendron-bearing lipids achieved efficient gene transfection of cells through synergetic action of the proton sponge effect and membrane fusion in combination with fusogenic lipid dioleoylphosphatidylethanolamine. Using those dendron-bearing lipids as a base material, we developed in this study a functional component of gene vectors that stabilizes lipoplexes by multiple PEG chains and promotes gene transfection through the proton sponge effect. We combined a poly(ethylene glycol) (PEG, 550 Da) graft to each of four chain ends of the G2 dendron-bearing lipid (P4-DL). An analogous molecule having single PEG graft was also synthesized using the G0 dendron-bearing lipid (P1-DL). Inclusion of P4-DL decreased the size of the G3 dendron-bearing lipid-based lipoplexes more efficiently than P1-DL. In addition, P4-DL-containing lipoplexes exhibited two-orders-higher transfection efficiency than P1-DL-containing lipoplexes with the same PEG graft density. These results indicate the superiority of multiple attachments of PEG graft chains to a lipid for heightened ability to increase colloidal stability of lipoplexes while retaining their transfection activity. The lipoplexes stabilized by P4-DL were small, around 250 nm, and achieved efficient transfection in the presence of serum. Therefore, P4-DL and its analogues will form the basis for production of efficient nonviral vectors for in vivo use.

We recently developed a novel family of cationic lipids consisting of a polyamidoamine (PAMAM) dendron and two dodecyl chains. Their transfection activity increases with increasing generation of the dendron moiety [Takahashi et al. (2003) Bioconjugate Chem. 14, 764-773]. In the present study, to elucidate the effect of hydrophobic tail moieties of the dendron-bearing lipids, two kinds of PAMAM G3 dendron-bearing lipids were synthesized with different alkyl lengths, DL-G3-2C18 and DL-G3-2C12. Their functions as gene vectors were compared. Irrespective of their different alkyl chain lengths, these dendron-bearing lipids formed complexes with plasmid DNA with similar efficiency. However, their complex sizes differed markedly: DL-G3-2C18 lipoplexes exhibited much smaller diameters than DL-G3-2C12 lipoplexes. Interaction of the lipoplexes with heparin revealed that the DL-G3-2C18 lipoplexes required more heparin than DL-G3-2C12 lipoplexes to cause dissociation of plasmid DNA from the lipoplexes. Although the DL-G3-2C12 lipoplexes and DL-G3-2C18 lipoplexes transfected CV1 cells with similar efficiency in the absence of serum, only the latter retained high transfection activity in the presence of serum. These results indicate that hydrophobic interaction of alkyl chain moieties plays an important role in the increment of stability and the serum-resistant transfection activity for dendron-bearing lipid lipoplexes.

Dendrimers are unique polymers with globular shapes and well-defined structures. We previously prepared poly(amidoamine) (PAMAM) dendrimers having phenylalanine (Phe) residues at every chain end of the dendrimer as efficient gene carriers. In this study, we found that Phe-derivatized PAMAM dendrimers change their water solubility depending on temperature. The dendrimers were soluble in aqueous solutions at low temperatures, but they became water-insoluble at temperatures above a specific threshold, which is termed the lower critical solution temperature (LCST). Although the LCST of Phe-modified dendrimers decreased with increasing dendrimer generation, these dendrimers exhibited an LCST of 20-30 degrees C under physiological conditions. In addition, the LCST of the dendrimers was controlled by introducing isoleucine (Ile) residues at chain ends of dendrimers at varying ratios with respect to Phe residues. The PAMAM dendrimers are known to encapsulate various drug molecules. For these reasons, temperature-sensitive dendrimers might be useful as efficient drug carriers with controlled size and temperature-responsive properties.

A head-tail type polycation block copolymer, which is composed of the polyamidoamine (PAMAM) dendron and poly(L-lysine) (PLL) blocks, was newly designed as a nonviral gene vector in this study. This block copolymer (PAMAM dendron-PLL) was successfully synthesized in two steps: the synthesis of the PAMAM dendron block and the polymerization of the PLL block from the PAMAM dendron block. PAMAM dendron and PLL blocks in block copolymer showed independent deprotonation behavior, and their pK(a) were determined to be 6.8 and 9.0, respectively. The complexation with pDNA was evaluated by gel retardation assay and dye exclusion assay, and both assays indicated that pDNA was selectively complexed with PLL block of block copolymer. Also, the PAMAM dendron-PLL poplyplexes showed 10(2) fold higher transfection efficiency to HeLa cells as that for PLL polyplexes. This might be due to the buffering effect of the PAMAM dendron block. This block copolymer could produce a function share in each block, i.e., tail block complexed with pDNA and head block showed a buffering effect. This molecular design of the head-tail type block copolymer might provide a new approach for realizing in vivo gene therapy.

We designed poly(amidoamine) dendrimers with phenylalanine or leucine residues at their chain ends. Thereby, we achieved efficient gene transfection of cells through synergy of the proton sponge effect, which is induced by the internal tertiary amines of the dendrimer, and hydrophobic interaction by the hydrophobic amino acid residues in the dendrimer periphery. Dendrimers having 16, 29, 46, and 64 terminal phenylalanine residues were prepared by the reaction of the amine-terminated poly(amidoamine) G4 dendrimer and L-phenylalanine using condensing reagent 1,3-dicyclohexylcarbodiimide. Transfection activity of these phenylalanine-modified dendrimers for CV1 cells, an African green monkey kidney cell line, increased concomitant with the increasing number of the terminal phenylalanine residues, except for the dendrimer with 64 phenylalanine residues, which showed poor water solubility and hardly formed a complex with DNA at neutral pH. However, under weakly acidic conditions, the dendrimer with 64 phenylalanine residues formed a complex with DNA, thereby achieving highly efficient transfection. In contrast, the attachment of L-leucine residues was unable to improve the transfection activity of the parent dendrimer, probably because of the relatively lower hydrophobicity of this amino acid. The phenylalanine-modified dendrimer exhibited a higher transfection activity and a lower cytotoxicity than some widely used transfection reagents. For that reason, the phenylalanine-modified dendrimers are considered to be promising gene carriers.

YEp vectors carrying the GPD promoter and PGK terminator for constitutive expression showed high partition efficiencies specifically in [cir0] strains, when DNA fragments were inserted into the cloning site. These plasmids appeared to be more stable than yeast centromeric plasmids, being lost in less than 10−2 cells after each generation, and more than 90% of the cells carried the plasmids after 20 generations of growth in the absence of selective pressure. The REP3 region was essential together with the GPD promoter and PGK terminator for plasmid equipartitioning in [cir0] strains. The present results suggest that this host-vector system would be useful for astute observation of the phenotype caused by gene overexpression, and for heterogenous protein production using natural medium, because of efficient partitioning of the plasmid without selective pressure.

The process of dioxygen reduction catalyzed by cytochrome c oxidase was investigated by examining intact porcine mitochondrial preparations using a novel time-resolved resonance Raman measurement system at experimental accuracy levels equivalent to those of the reaction system of the solubilized and purified enzyme. The resonance Raman bands assignable to the initial three intermediates were detected at frequencies identical to those observed with purified enzyme preparations. However, the lifetime of the initial intermediate (the oxygenated species) in the mitochondrial preparation was found to be significantly longer than that observed in purified preparations, suggesting that control of the stability of the oxygenated species is imposed by the mitochondrial membrane system.

1) 子宮頸部擦過細胞標本10万403検体中21検体 (0.02%) にいわゆるヘマトイジン結晶を認めた.2) 21例中19例の標本は炎症所見が認められ, 7例では背景に出血を認めた. また21例中7例は, 妊娠または分娩後1年以内の症例であった.3) ヘマトイジン結晶は, 黄褐色または赤褐色で直径2u～100uの放射状の結晶であり・標本中には1～28個の結晶が散在し, その周囲には組織球や好中球がロゼット様に分布していた.4) ヘマトイジン結晶の認められた21例中16例の標本に特殊染色を行った結果・PAS染色陽性, アルシアン青陰性, スタインのヨード法陰性, ベルリン青染色陰性, 酵素抗体染色 (フェリチン) 陰性であった. また, PAS染色陽性であったヘマトイジン結晶は, ジアスターゼ・アミラーゼによっても消化されないことより, この物質は血液中の蛋白物質の結晶であることが示唆された.5) 以上のことよりヘマトイジン結晶という呼称は適当ではなく, 再検討が必要である.