Species richness and species composition of fungal communities associated with cellulose decomposition at different altitudes on the Tibetan Plateau

Aims The aims of this study were to compare the fungal communities developing on cotton strips at three different altitudes on the Tibetan Plateau and to assess the environmental variables influencing them.Methods Cotton strips that had been buried in soil for a year were sampled at three sites at different altitudes (4500, 4950 and 5200 m) located on a southeast-facing slope on the Nyainqentanglha Mountains near Damxung. The fungi on the cotton strips were isolated using a modified washing method. The decomposition abilities and colony growth properties of the major species cultured in pure-culture conditions were investigated and compared. Canonical correspondence analysis (CCA) was used to evaluate the relationships between fungal community composition and environmental variables (altitude, soil depth, soil water content [SWC], plant root mass and gravel content).Important findings A total of 24 species were isolated from the cotton strips, and 12 species occurred frequently and were regarded as major species. The number of fungal species was lower at the 4950-m altitude site than at the other two sites, indicating that not only altitude but also other factors affected the number of species present. All of the major species were able to decompose the cotton strips. In the CCA ordination, automatic forward selection revealed that altitude, SWC and plant root mass significantly affected fungal species composition. Our results suggest that species number and the composition of cellulolytic fungal communities are highly correlated with environmental variables as well as altitude in the alpine meadow on the Tibetan Plateau.     

Update of mouse microsatellite database of Japan (MMDBJ).

We updated a database of microsatellite marker polymorphisms found in inbred strains of the mouse, most of which were derived from the wild stocks of four Mus musculus subspecies, M. m. domesticus, M. m. musculus, M. m.castaneus and M. m. molossinus. The major aim of constructing this database was to establish the genetic status of these inbred strains as resources for linkage analysis and positional cloning. The inbred strains incorporated in our database are A/J, C57BL/6J, CBA/J, DBA/2J, SM/J, SWR/J, 129Sv/J, MSM/Ms, JF1/Ms, CAST/Ei, NC/Nga, BLG2/Ms, NJL/Ms, PGN2/Ms, SK/CamEi and SWN/Ms, which have not or have only been poorly incorporated in the Whitehead Institute/MIT (WI/MIT) microsatellite database. The number of polymorphic microsatellite loci incorporated in our database is over 1,000 in all strains, and the URL site for our database is located at http:// www.shigen.nig.ac.jp /mouse/mmdbj/mouse.html.     

The Influence of 5-HTTLPR Genotype on the Association between the Plasma Concentration and Therapeutic Effect of Paroxetine in Patients with Major Depressive Disorder

Introduction

The efficacy of treatment with selective serotonin reuptake inhibitors in patients with major depressive disorder (MDD) can differ depending on the patient''s serotonin transporter-linked polymorphic region (5-HTTLPR) genotype, and the effects of varying plasma concentrations of drugs can also vary. We investigated the association between the paroxetine plasma concentration and clinical response in patients with different 5-HTTLPR genotypes.

Methods

Fifty-one patients were enrolled in this study. The Montgomery-Asberg Depression Rating Scale (MADRS) was used to evaluate patients at 0, 1, 2, 4, and 6 weeks. The patients'' paroxetine plasma concentrations at week 6 were measured using high-performance liquid chromatography. Additionally, their 5-HTTLPR polymorphisms (alleles S and L) were analyzed using a polymerase chain reaction with specific primers. We divided the participants into two groups based on their L haplotype: the SS group and the SL and LL group. We performed single and multiple regression analyses to investigate the associations between MADRS improvement and paroxetine plasma concentrations or other covariates for each group.

Results

There were no significant differences between the two groups with regard to demographic or clinical data. In the SS group, the paroxetine plasma concentration was significantly negatively correlated with improvement in MADRS at week 6. In the SL and LL group, the paroxetine plasma concentration was significantly positively correlated with improvement in MADRS at week 6 according to the results of the single regression analysis; however, it was not significantly correlated with improvement in MADRS at week 6 according to the results of the multiple regression analysis.

Conclusion

Among patients with MDD who do not respond to paroxetine, a lower plasma concentration or a lower oral dose of paroxetine might be more effective in those with the SS genotype, and a higher plasma concentration might be more effective in those with the SL or LL genotype.     

Compilation of All Genes Encoding Bacterial Two-component Signal Transducers in the Genome of the Cyanobacterium, Synechocystis sp. Strain PCC 6803

Bacteria have devised sophisticated signaling systems for elicitinga variety of adaptive responses to their environment, whichare generally referred to as the "two-component regulatory system."The widespread occurrence of the two-component systems in bothprokaryotes and eukaryotes implies that it is a powerful devicefor a wide variety of adaptive responses of cells to their environment.The two-component signal transducers contain one or more ofthree conserved and characteristic phosphotransfer signalingdomains, named the "transmitter, receiver, and alternative transmitter."The recently determined entire genomic sequence of Synechocystissp. strain PCC 6803 allowed us to compile systematically a completelist of genes encoding such two-component signal transductionproteins. The results of such an effort, made in this study,revealed that at least 80 ORFs were identified as members ofthe two-component signal transducers in this single speciesof cyanobacteria.     

First finding of urease-positive thermophilic strains of Campylobacter in river water in the Far East, namely, in Japan and their phenotypic and genotypic characterization

Two strains of urease-positive thermophilic Campylobacter (UPTC), CF89–12 and CF89–14, which were identified as UPTC by biochemical characterization, were found for the first time in river water in the Far East, namely, in Japan. The biochemical characteristics were identical to those of strains described previously by Bolton and colleagues. Furthermore, these two strains were positive for arylsulphatase. Consequently, it was demonstrated that UPTC may possibly be differentiated phenotypically from Campylobacter lari by the arylsulphatase test, as well as urease and nalidixic acid tests. Analysis by pulsed-field gel electrophoresis (PFGE) after digestion with Apa I, Sal I and Sma I, which were found to produce distributions of DNA fragments to be suitable for analysis of the genomic DNA from the thermophilic Campylobacter , respectively, demonstrated that these three restriction enzymes produced distributions of a relatively limited number of genomic DNA fragments and also demonstrated that the PFGE profiles obtained with the three restriction enzymes were indistinguishable between the two strains, respectively. The PFGE analysis and conventional fixed-field agarose gel electrophoresis suggested that the both genomes were approximately 1862 kb in length. Even though the two isolates of UPTC were isolated from water in different rivers in Japan, the results suggested that a single strain. as opposed to two distinct strains, was isolated. PFGE profiles after digestion with Sal I and Sma I, respectively, were also demonstrated to be distinctly different among strains isolated in Japan and previously in Europe. This is the first example of the isolation of UPTC from natural sources in countries other than those in Europe.     

Synthesis of desmosterol and epidesmosterol from hyodeoxycholic acid

A new synthesis of desmosterol was described using hyodeoxycholic acid (3,6-dihydroxy-5β-cholanic acid) as a starting material. Epidesmosterol (3-hydroxycholesta-5,24-diene) was also synthesized for the first time from the same starting material.     

Induction of apoptotic change in the rat hippocampus caused by ferric nitrilotriacetate

Iron, a source of oxidative stress, plays a major role in the pathology of neurodegenerative disease. In Alzheimer's disease, the hippocampus is vulnerable to oxidative stress, leading to impairment in memory formation. In our previous study, a brain oxidative reaction was induced after intraperitoneal injection of ferric nitrilotriacetate (Fe-NTA). However, since only a small amount of iron reached the brain in the previous study, Fe-NTA was administered into the hippocampus using an osmotic pump in this study. After continuous injection of Fe-NTA for 2 weeks, a high level of apoptotic change was induced in the hippocampus, in accordance with the iron localization. After injection for 4 weeks, the hippocampus was totally destroyed. A small amount of iron infiltrated into the cerebral cortex and the striatum, and deposition was observed at the choroid plexus and ependymal cells. However, no apoptotic reaction or clear tissue injury was observed in these areas. In addition, muscarinic acetylcholine receptors (M1, M2, and M4) were decreased in both the cortex and hippocampus while it increased in the striatum. Thus, the hippocampus is likely vulnerable to oxidative stress from Fe-NTA, and the oxidative stress is considered to bring the disturbance in the muscarinic acetylcholine receptors.     

Minor contribution of cytosolic Ca2+ transients to the pacemaker rhythm in guinea pig sinoatrial node cells

The question of the extent to which cytosolic Ca(2+) affects sinoatrial node pacemaker activity has been discussed for decades. We examined this issue by analyzing two mathematical pacemaker models, based on the "Ca(2+) clock" (C) and "membrane clock" (M) hypotheses, together with patch-clamp experiments in isolated guinea pig sinoatrial node cells. By applying lead potential analysis to the models, the C mechanism, which is dependent on potentiation of Na(+)/Ca(2+) exchange current via spontaneous Ca(2+) release from the sarcoplasmic reticulum (SR) during diastole, was found to overlap M mechanisms in the C model. Rapid suppression of pacemaker rhythm was observed in the C model by chelating intracellular Ca(2+), whereas the M model was unaffected. Experimental rupturing of the perforated-patch membrane to allow rapid equilibration of the cytosol with 10 mM BAPTA pipette solution, however, failed to decrease the rate of spontaneous action potential within ～30 s, whereas contraction ceased within ～3 s. The spontaneous rhythm also remained intact within a few minutes when SR Ca(2+) dynamics were acutely disrupted using high doses of SR blockers. These experimental results suggested that rapid disruption of normal Ca(2+) dynamics would not markedly affect spontaneous activity. Experimental prolongation of the action potentials, as well as slowing of the Ca(2+)-mediated inactivation of the L-type Ca(2+) currents induced by BAPTA, were well explained by assuming Ca(2+) chelation, even in the proximity of the channel pore in addition to the bulk cytosol in the M model. Taken together, the experimental and model findings strongly suggest that the C mechanism explicitly described by the C model can hardly be applied to guinea pig sinoatrial node cells. The possible involvement of L-type Ca(2+) current rundown induced secondarily through inhibition of Ca(2+)/calmodulin kinase II and/or Ca(2+)-stimulated adenylyl cyclase was discussed as underlying the disruption of spontaneous activity after prolonged intracellular Ca(2+) concentration reduction for >5 min.