BACKGROUND: Peritoneal dialysis has become commonly used for renal replacement therapy; however, some patients withdraw from peritoneal dialysis due to complications, including peritoneal dialysis-related peritonitis, resulting in the low number of patients on peritoneal dialysis. Risk factors for peritoneal dialysis withdrawal due to peritoneal dialysis-related peritonitis are less certain. This retrospective study aimed to investigate these risk factors. METHODS: We retrospectively analyzed clinical characteristics, laboratory data, and causative microorganisms of 204 episodes of peritoneal dialysis-related peritonitis between 2007 and 2018 at our institution. RESULTS: Of the 204 episodes, 38 resulted in withdrawal from peritoneal dialysis due to peritoneal dialysis-related peritonitis. The number of peritonitis episodes per patient-year and the incidence of cardiovascular disease were significantly higher in the withdrawal group. Similarly, this group had low levels of serum creatinine, urea nitrogen, serum albumin, alanine aminotransferase, cholinesterase and high C-reactive protein, and second dialysate cell counts after antibiotic administration. Multivariate logistic regression analysis revealed that serum albumin (odds ratio: 0.465; 95% confidence interval: 0.249-0.868; P=0.016) and cardiovascular disease (odds ratio: 2.508; 95% confidence interval: 1.184-5.315; P=0.016) exhibited significant differences. CONCLUSIONS: The results of this study suggest that hypoalbuminemia and the presence of cardiovascular disease were independent risk factors for withdrawal from peritoneal dialysis due to peritoneal dialysis-related peritonitis.
Social behaviour is a complex construct that is reported to include several components of social approach, interaction and recognition memory. Alzheimer's disease (AD) is mainly characterized by progressive dementia and is accompanied by cognitive impairments, including a decline in social ability. The cholinergic system is a potential constituent for the neural mechanisms underlying social behaviour, and impaired social ability in AD may have a cholinergic basis. However, the involvement of cholinergic function in social behaviour has not yet been fully understood. Here, we performed a selective elimination of cholinergic cell groups in the basal forebrain in mice to examine the role of cholinergic function in social interaction and social recognition memory by using the three-chamber test. Elimination of cholinergic neurons in the medial septum (MS) and vertical diagonal band of Broca (vDB) caused impairment in social interaction, whereas ablating cholinergic neurons in the nucleus basalis magnocellularis (NBM) impaired social recognition memory. These impairments were restored by treatment with cholinesterase inhibitors, leading to cholinergic system activation. Our findings indicate distinct roles of MS/vDB and NBM cholinergic neurons in social interaction and social recognition memory, suggesting that cholinergic dysfunction may explain social ability deficits associated with AD symptoms.
Recognition memory requires processing of various types of information such as objects and locations. Impairment in recognition memory is a prominent feature of amnesia and a symptom of Alzheimer's disease (AD). Basal forebrain cholinergic neurons contain two major groups, one localized in the medial septum (MS)/vertical diagonal band of Broca (vDB), and the other in the nucleus basalis magnocellularis (NBM). The roles of these cell groups in recognition memory have been debated, and it remains unclear how they contribute to it. We use a genetic cell targeting technique to selectively eliminate cholinergic cell groups and then test spatial and object recognition memory through different behavioural tasks. Eliminating MS/vDB neurons impairs spatial but not object recognition memory in the reference and working memory tasks, whereas NBM elimination undermines only object recognition memory in the working memory task. These impairments are restored by treatment with acetylcholinesterase inhibitors, anti-dementia drugs for AD. Our results highlight that MS/vDB and NBM cholinergic neurons are not only implicated in recognition memory but also have essential roles in different types of recognition memory.
Bordetella bronchiseptica colonizes the respiratory tracts of a wide variety of mammals and causes a range of diseases, from lethal pneumonia to asymptomatic chronic infection. We report the complete genome sequence of Bordetella bronchiseptica strain S798, isolated from a pig with atrophic rhinitis in Japan.
The role of macrophage lipoprotein lipase (LpL) in the development of atherosclerosis and adiposity was examined in macrophage LpL knockout (MLpLKO) mice. MLpLKO mice were generated using cre-loxP gene targeting. Loss of LpL in macrophages did not alter plasma LpL activity or lipoprotein levels. Incubation of apolipoprotein E (ApoE)-deficient beta-VLDL with peritoneal macrophages from ApoE knockout mice lacking macrophage LpL (MLpLKO/ApoEKO) led to less cholesteryl ester formation than that found with ApoEKO macrophages. MLpLKO/ApoEKO macrophages had reduced intracellular triglyceride levels, with decreased CD36 and carnitine palmitoyltransferase-1 mRNA levels compared with ApoEKO macrophages, when incubated with VLDL. Although both MLpLKO/ApoEKO and ApoEKO mice developed comparable hypercholesterolemia in response to feeding with a Western-type diet for 12 weeks, atherosclerosis was less in MLpLKO/ApoEKO mice. Epididymal fat mass and gene expression levels associated with inflammation did not differ between the two groups. In conclusion, macrophage LpL plays an important role in the development of atherosclerosis but not adiposity.
AIM: Adipocyte lipolysis is mediated by a family of triglyceride (TG) lipases consisting of hormone-sensitive lipase (LIPE), adipose triglyceride lipase (PNPLA2) and carboxylesterase 1 (CES1); however, little is known about the relationship between the expression of each gene in different depots and TG lipase activity or obesity. METHOD: We measured both mRNA expression levels of the lipolytic enzymes (LIPE, PNPLA2 and CES1) and TG lipase activities of biopsy samples obtained from subcutaneous, omental and mesenteric adipose tissues of 34 patients who underwent abdominal surgery. The results were correlated with clinical parameters: adiposity measures, parameters for insulin resistance and plasma lipid levels. RESULTS: PNPLA2 mRNA levels were slightly higher in omental fat than subcutaneous fat. Cytosolic TG lipase activities were positively correlated with the mRNA levels of CES1 in subcutaneous fat and mesenteric fat, while they were correlated with those of PNPLA2 in omental fat. The mRNA levels of LIPE were negatively correlated with various measures of adiposity in subcutaneous fat. The mRNA levels of CES1 were positively correlated with various measures of adiposity, particularly those estimated by CT in the three depots; they were also positively correlated with plasma LDL-cholesterol levels in omental fat. In contrast, the mRNA levels of PNPLA2 were not significantly associated with adiposity. CONCLUSIONS: The positive correlations of the expression of CES1 with cytosolic TG lipase activities as well as with adiposity suggest that CES1 is involved in lipolysis, thereby contributing to the development of obesity-associated phenotypes. On the other hand, the expression of LIPE is negatively correlated with adiposity. These distinct regulatory patterns of lipolytic genes may underlie the complex phenotypes associated with human obesity.
Lecithin-cholesterol acyltransferase (LCAT) is an important enzyme involved in the esterification of cholesterol. Here, we report a novel point mutation in the LCAT gene of a 63-year-old female with characteristics of classic familial LCAT deficiency. The patient's clinical manifestations included corneal opacity, mild anemia, mild proteinuria and normal renal function. She had no sign of coronary heart disease. Her LCAT activity was extremely low. DNA sequencing revealed a point mutation in exon 5 of the LCAT gene: a G to C substitution converting Gly(179) to an Arg, located in one of the catalytic triads of the enzyme. In vitro expression of recombinant LCAT proteins in HEK293 cells showed that the mutant G179R protein was present in the cell lysate, but not the culture medium. LCAT activity was barely detectable in the cell lysate or medium of the cells expressing the G179R mutant. This novel missense mutation seems to cause a complete loss of catalytic activity of LCAT, which is also defective in secretion.
The lux operon is an uncommon gene cluster. To find the pathway through which the operon has been transferred, we sequenced the operon and both flanking regions in four typical luminous species. In Vibrio cholerae NCIMB 41, a five-gene cluster, most genes of which were highly similar to orthologues present in Gram-positive bacteria, along with the lux operon, is inserted between VC1560 and VC1563, on chromosome 1. Because this entire five-gene cluster is present in Photorhabdus luminescens TT01, about 1.5 Mbp upstream of the operon, we deduced that the operon and the gene cluster were transferred from V. cholerae to an ancestor of Pr. luminescens. Because in both V. fischeri and Shewanella hanedai, luxR and luxI were found just upstream of the operon, we concluded that the operon was transferred from either species to the other. Because most of the genes flanking the operon were highly similar to orthologues present on chromosome 2 of vibrios, we speculated that the operon of most species is located on this chromosome. The undigested genomic DNAs of five luminous species were analysed by pulsed-field gel electrophoresis and Southern hybridization. In all the species except V. cholerae, the operons are located on chromosome 2.
The genome of Aspergillus oryzae, a fungus important for the production of traditional fermented foods and beverages in Japan, has been sequenced. The ability to secrete large amounts of proteins and the development of a transformation system have facilitated the use of A. oryzae in modern biotechnology. Although both A. oryzae and Aspergillus flavus belong to the section Flavi of the subgenus Circumdati of Aspergillus, A. oryzae, unlike A. flavus, does not produce aflatoxin, and its long history of use in the food industry has proved its safety. Here we show that the 37-megabase (Mb) genome of A. oryzae contains 12,074 genes and is expanded by 7-9 Mb in comparison with the genomes of Aspergillus nidulans and Aspergillus fumigatus. Comparison of the three aspergilli species revealed the presence of syntenic blocks and A. oryzae-specific blocks (lacking synteny with A. nidulans and A. fumigatus) in a mosaic manner throughout the genome of A. oryzae. The blocks of A. oryzae-specific sequence are enriched for genes involved in metabolism, particularly those for the synthesis of secondary metabolites. Specific expansion of genes for secretory hydrolytic enzymes, amino acid metabolism and amino acid/sugar uptake transporters supports the idea that A. oryzae is an ideal microorganism for fermentation.
To understand how the direction of root growth changes in response to obstacles, light, and gravity, we characterized an Arabidopsis thaliana mutant, wavy growth 2 (wav2), whose roots show a short-pitch pattern of wavy growth on inclined agar medium. The roots of the wav2 mutant bent with larger curvature than those of the wild-type seedlings in wavy growth and in gravitropic and phototropic responses. The cell file rotations of the root epidermis of wav2-1 in the wavy growth pattern were enhanced in both right-handed and left-handed rotations. WAV2 encodes a protein belonging to the BUD EMERGENCE 46 family with a transmembrane domain at the N terminus and an alpha/beta-hydrolase domain at the C terminus. Expression analyses showed that mRNA of WAV2 was expressed strongly in adult plant roots and seedlings, especially in the root tip, the cell elongation zone, and the stele. Our results suggest that WAV2 is not involved in sensing environmental stimuli but that it negatively regulates stimulus-induced root bending through inhibition of root tip rotation.
Several types of jasomonic acid (JA) derivatives, including JA--amino acid conjugates, a JA--biotin conjugate, a JA--dexamethasone heterodimer, and a JA-fluoresceine conjugate, were prepared as candidates for molecular probes to identify JA--binding proteins. These JA derivatives, excepting the JA--fluoresceine conjugate, exhibited significant biological activities in a rice seedling assay, a rice phytoalexin-inducing assay, and/or a soybean phenylalanine ammonia-lyase-inducing assay. These JA derivatives could therefore be useful probes for identifying JA--binding proteins. The activity spectra of the prepared compounds were different from each other, suggesting that different types of JA receptors were involved in the perception of JA derivatives in the respective bioassays.
Title: Hydrotropism in abscisic acid, wavy, and gravitropic mutants of Arabidopsis thaliana Takahashi N, Goto N, Okada K, Takahashi H Ref: Planta, 216:203, 2002 : PubMed
We have developed experimental systems to study hydrotropism in seedling roots of Arabidopsis thaliana (L.) Heynh. Arabidopsis roots showed a strong curvature in response to a moisture gradient, established by applying 1% agar and a saturated solution of KCl or K(2)CO(3) in a closed chamber. In this system, the hydrotropic response overcame the gravitropic response. Hydrotropic curvature commenced within 30 min and reached 80-100 degrees within 24 h of hydrostimulation. When 1% agar and agar containing 1 MPa sorbitol were placed side-by-side in humid air, a water potential gradient formed at the border between the two media. Although the gradient changed with time, it still elicited a hydrotropic response in Arabidopsis roots. The roots curved away from 0.5-1.5 MPa of sorbitol agar. Various Arabidopsis mutants were tested for their hydrotropic response. Roots of aba1-1 and abi2-1 mutants were less sensitive to hydrotropic stimulation. Addition of abscisic acid restored the normal hydrotropic response in aba1-1 roots. In comparison, mutants that exhibit a reduced response to gravity and auxin, axr1-3 and axr2-1, showed a hydrotropic response greater than that of the wild type. Wavy mutants, wav2-1 and wav3-1, showed increased sensitivity to the induction of hydrotropism by the moisture gradient. These results suggest that auxin plays divergent roles in hydrotropism and gravitropism, and that abscisic acid plays a positive role in hydrotropism. Furthermore, hydrotropism and the wavy response may share part of a common molecular pathway controlling the directional growth of roots.
Title: The DEFECTIVE IN ANTHER DEHISCIENCE gene encodes a novel phospholipase A1 catalyzing the initial step of jasmonic acid biosynthesis, which synchronizes pollen maturation, anther dehiscence, and flower opening in Arabidopsis Ishiguro S, Kawai-Oda A, Ueda J, Nishida I, Okada K Ref: Plant Cell, 13:2191, 2001 : PubMed
The Arabidopsis mutant defective in anther dehiscence1 (dad1) shows defects in anther dehiscence, pollen maturation, and flower opening. The defects were rescued by the exogenous application of jasmonic acid (JA) or linolenic acid, which is consistent with the reduced accumulation of JA in the dad1 flower buds. We identified the DAD1 gene by T-DNA tagging, which is characteristic to a putative N-terminal transit peptide and a conserved motif found in lipase active sites. DAD1 protein expressed in Escherichia coli hydrolyzed phospholipids in an sn-1-specific manner, and DAD1-green fluorescent protein fusion protein expressed in leaf epidermal cells localized predominantly in chloroplasts. These results indicate that the DAD1 protein is a chloroplastic phospholipase A1 that catalyzes the initial step of JA biosynthesis. DAD1 promoter::beta-glucuronidase analysis revealed that the expression of DAD1 is restricted in the stamen filaments. A model is presented in which JA synthesized in the filaments regulates the water transport in stamens and petals.
BACKGROUND:
The N-terminal pyroglutamyl (pGlu) residue of peptide hormones, such as thyrotropin-releasing hormone (TRH) and luteinizing hormone releasing hormone (LH-RH), confers resistance to proteolysis by conventional aminopeptidases. Specialized pyroglutamyl peptidases (PGPs) are able to cleave an N-terminal pyroglutamyl residue and thus control hormonal signals. Until now, no direct or homology-based three-dimensional structure was available for any PGP.
RESULTS:
The crystal structure of pyroglutamyl peptidase I (PGP-I) from Bacillus amyloliquefaciens has been determined to 1.6 A resolution. The crystallographic asymmetric unit of PGP-I is a tetramer of four identical monomers related by noncrystallographic 222 symmetry. The protein folds into an alpha/beta globular domain with a hydrophobic core consisting of a twisted beta sheet surrounded by five alpha helices. The structure allows the function of most of the conserved residues in the PGP-I family to be identified. The catalytic triad comprises Cys144, His168 and Glu81.
CONCLUSIONS:
The catalytic site does not have a conventional oxyanion hole, although Cys144, the sidechain of Arg91 and the dipole of an alpha helix could all stabilize a negative charge. The catalytic site has an S1 pocket lined with conserved hydrophobic residues to accommodate the pyroglutamyl residue. Aside from the S1 pocket, there is no clearly defined mainchain substrate-binding region, consistent with the lack of substrate specificity. Although the overall structure of PGP-I resembles some other alpha/beta twisted open-sheet structures, such as purine nucleoside phosphorylase and cutinase, there are important differences in the location and organization of the active-site residues. Thus, PGP-I belongs to a new family of cysteine proteases.
Title: [Synthesis of estimated metabolites of 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinoline monohydrochloride monohydrate (NIK-247). I. Synthesis of mono-hydroxylated metabolites] Komatsu T, Yano M, Inada H, Iwamoto M, Okada K, Suzuki K Ref: Yakugaku Zasshi, 115:1016, 1995 : PubMed
The two mono-hydroxylated metabolites of 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinoline monohydrochloride monohydrate (NIK-247), which is a new drug for the treatment of dementia, were synthesized to determine their chemical structures. Reduction of two tricyclic ketones, 9-amino-1,2,3,5,6,7-hexahydro-8H-cyclopenta[b]quinolin-8-one and 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]-quinolin-1-one, with NaBH4 afforded the corresponding racemic alcohols. The optically active mono-hydroxylated metabolites, (+)-9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-8-ol and (+)-9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-1-ol, were obtained by optical resolution of each racemic alcohol using (+)-di-p-toluoyl-D-tartaric acid.
