Добірка наукової літератури з теми "C. taiwanensis"

Rhizobia, the nitrogen-fixing symbionts of legumes, are polyphyletic bacteria distributed in many alpha- and beta-proteobacterial genera. They likely emerged and diversified through independent horizontal transfers of key symbiotic genes. To replay the evolution of a new rhizobium genus under laboratory conditions, the symbiotic plasmid of Cupriavidus taiwanensis was introduced in the plant pathogen Ralstonia solanacearum, and the generated proto-rhizobium was submitted to repeated inoculations to the C. taiwanensis host, Mimosa pudica L. This experiment validated a two-step evolutionary scenario of key symbiotic gene acquisition followed by genome remodeling under plant selection. Nodulation and nodule cell infection were obtained and optimized mainly via the rewiring of regulatory circuits of the recipient bacterium. Symbiotic adaptation was shown to be accelerated by the activity of a mutagenesis cassette conserved in most rhizobia. Investigating mutated genes led us to identify new components of R. solanacearum virulence and C. taiwanensis symbiosis. Nitrogen fixation was not acquired in our short experiment. However, we showed that post-infection sanctions allowed the increase in frequency of nitrogen-fixing variants among a non-fixing population in the M. pudica–C. taiwanensis system and likely allowed the spread of this trait in natura. Experimental evolution thus provided new insights into rhizobium biology and evolution.

Cephennomicrus Reitter, 1907 (Staphylinidae, Scydmaeninae, Cephenniini) of Japan and Taiwan is revised. Four species groups are established for the following species: the nomurai group—C. nomurai (Jałoszyński & Hoshina, 2003) (Japan), C. hobbiti (Jałoszyński & Hoshina, 2003) (Japan), C. disjunctus (Jałoszyński, S. Arai & K. Arai, 2004) status n. (Japan), C. inflatus sp. n. (Taiwan), and C. crucifer sp. n. (Taiwan); the taiwanensis group—C. taiwanensis (Jałoszyński, 2004) (Taiwan), C. iriomotensis sp. n. (Japan), C. nagoanus sp. n. (Japan), C. tsurui sp. n. (Taiwan), C. delicatissimus sp. n. (Taiwan), and C. imago sp. n. (Taiwan); the japonigenus group—C. japonigenus (Jałoszyński & Hoshina, 2003) (Japan), and C. pseudojaponigenus sp. n. (Japan); the fujianus group—C. fujianus (Jałoszyński, 2005) (from China, not treated in this paper), and C. pseudofujianus sp. n. (Taiwan). Three species remain incertae sedis within the genus: C. okinawanus (Jałoszyński, S. Arai & K. Arai, 2004) (Japan), C. cactiformis (Jałoszyński & Hoshina, 2003) (Japan), and C. taitungensis sp. n. (Taiwan). Habitus of all treated species and aedeagi are illustrated. Detailed morphology of the nomurai and taiwanensis species groups was studied, described and illustrated based on disarticulated specimens of C. nomurai and C. delicatissimus. Comparative study suggests a separate position of the nomurai group as a subgenus or genus; however, Oriental Cephennomicrus must be studied in detail before formal taxonomic changes can be made.

The genus Cimicifuga is one of the smallest genera in the family Ranunculaceae. Cimicifugae Rhizoma originated from rhizomes of Cimicifuga simplex, and C. dahurica, C. racemosa, C. foetida, and C. heracleifolia have been used as anti-inflammatory, analgesic and antipyretic remedies in Chinese traditional medicine. Inflammation is related to many diseases. Cimicifuga taiwanensis was often used in folk therapy in Taiwan for inflammation. Phytochemical investigation and chromatographic separation of extracts from the roots of Cimicifuga taiwanensis has led to the isolation of six new compounds: cimicitaiwanins A–F (1–6, respectively). The structures of the new compounds were unambiguously elucidated on the basis of extensive spectroscopic data analysis (1D- and 2D-NMR, MS, and UV) and comparison with the literature data. The effect of some isolates on the inhibition of NO production in lipopolysaccharide-activated RAW 264.7 murine macrophages was evaluated. Of the isolates, 3–6 exhibited potent anti-NO production activity, with IC50 values ranging from 6.54 to 24.58 μM, respectively, compared with that of quercetin, an iNOS inhibitor with an IC50 value of 34.58 μM. This is the first report on metabolite from the endemic Taiwanese plant-C. taiwanensis.

Genetic diversity within and genetic differentiation among three populations of Chamaecyparisformosensis Matsum. and two populations of Chamaecyparistaiwanensis Masam. & Suzuki were investigated using one-year-old seedlings collected from central and northern Taiwan. For C. formosensis 330 seedlings from 33 seed trees were used, while for C. taiwanensis 260 seedlings from 26 seed trees were used. Eleven enzyme systems were investigated. In C. formosensis, 5 of the 21 loci examined were polymorphic. The average percentage of polymorphic loci per population was 20.6% at the 99% criterion for polymorphism. Mean expected heterozygosity ranged from 0.079 to 0.100 in the different populations. On average, there were 6.6 to 9.2% heterozygous loci per individual and 1.24 to 1.29 alleles per locus; the effective number of alleles per locus ranged from 1.09 to 1.11. In C. taiwanensis, 7 of the 20 loci examined were polymorphic and the average percentage of polymorphic loci per population was 22.5%. Mean expected heterozygosity ranged from 0.044 to 0.060. On average there were 4.5 to 5.6% heterozygous loci per individual and 1.45 alleles per locus; the effective number of alleles per locus ranged from 1.05 to 1.08. The surprisingly low expected heterozygosity and percentage of polymorphic loci compared with other conifer probably reflects the insular nature of these species. Partitioning the genetic variability into within- and among-population components with F-statistics led to an estimate of within-population variation of 95% of the total variation in both C. formosensis and C. taiwanensis. Chamaecyparisformosensis had a positive fixation index (0.109) that was significantly different from zero at the 5% level, indicating that most loci have slightly higher frequencies of homozygotes. Chamaecyparistaiwanensis, however, had a fixation index close to zero (0.036), which suggests that most loci are in Hardy–Weinberg equilibrium. The genetic distance between C. formosensis and C. taiwanensis was 0.70, which clearly separates these two species.

Low temperatures and high pH generally inhibit the biodenitrification. Thus, it is important to explore the psychrotrophic and alkali-resisting microorganism for degradation of nitrogen. This research was mainly focused on the identification of a psychrotrophic strain and preliminary explored its denitrification characteristics. The new strain J was isolated using the bromothymol blue solid medium and identified as Pseudomonas taiwanensis on the basis of morphology and phospholipid fatty acid as well as 16S rRNA gene sequence analyses, which is further testified to work efficiently for removing nitrate from wastewater at low temperature circumstances. This is the first report that Pseudomonas taiwanensis possessed excellent tolerance to low temperature, with 15°C as its optimum and 5°C as viable. The Pseudomonas taiwanensis showed unusual ability of aerobic denitrification with the nitrate removal efficiencies of 100% at 15°C and 51.61% at 5°C. Single factor experiments showed that the optimal conditions for denitrification were glucose as carbon source, 15°C, shaking speed 150 r/min, C/N 15, pH≥7, and incubation quantity 2.0 × 106 CFU/mL. The nitrate and total nitrogen removal efficiencies were up to 100% and 93.79% at 15°C when glucose is served as carbon source. These results suggested that strain J had aerobic denitrification ability, as well as the notable ability to tolerate the low temperature and high pH.

Polyhydroxyalkanoates (PHA) are microbial polyesters that have recently come to the forefront of interest due to their biodegradability and production from renewable sources. A potential increase in competitiveness of PHA production process comes with a combination of the use of thermophilic bacteria with the mutual use of waste substrates. In this work, the thermophilic bacterium Tepidimonas taiwanensis LMG 22826 was identified as a promising PHA producer. The ability to produce PHA in T. taiwanensis was studied both on genotype and phenotype levels. The gene encoding the Class I PHA synthase, a crucial enzyme in PHA synthesis, was detected both by genome database search and by PCR. The microbial culture of T. taiwanensis was capable of efficient utilization of glucose and fructose. When cultivated on glucose as the only carbon source at 50 °C, the PHA titers reached up to 3.55 g/L, and PHA content in cell dry mass was 65%. The preference of fructose and glucose opens the possibility to employ T. taiwanensis for PHA production on various food wastes rich in these abundant sugars. In this work, PHA production on grape pomace extracts was successfully tested.

An actinomycete strain (0345M-7T) was isolated from a soil sample from Yilan county, Taiwan. The isolate displayed substrate mycelia, upon which were borne short spore chains. The spore chains were composed of non-motile, smooth-surfaced, oval spores. Strain 0345M-7T had meso-diaminopimelic acid in its peptidoglycan. Whole-cell sugars were galactose, glucose, arabinose and ribose. The only phospholipid found was phosphatidylethanolamine. The predominant menaquinone was MK-9(H4). Mycolic acids were not detected. Major cellular fatty acids were iso-C16 : 0 (38.1 %) and C17 : 1 (25.4 %). The DNA G+C content of strain 0345M-7T was 68.9 mol%. On the basis of phenotypic and genotypic data, it is proposed that strain 0345M-7T (=BCRC 16802T=KCTC 19116T) should be classified as the type strain of a novel species of the genus Amycolatopsis, Amycolatopsis taiwanensis sp. nov.

The β-rhizobium Cupriavidus taiwanensis is a nitrogen-fixing symbiont of Mimosa pudica. Nod factors produced by this species were previously found to be pentameric chitin-oligomers carrying common C18:1 or C16:0 fatty acyl chains, N-methylated and C-6 carbamoylated on the nonreducing terminal N-acetylglucosamine and sulfated on the reducing terminal residue. Here, we report that, in addition, C. taiwanensis LMG19424 produces molecules where the reducing sugar is open and oxidized. We identified a novel nodulation gene located on the symbiotic plasmid pRalta, called noeM, which is involved in this atypical Nod factor structure. noeM encodes a transmembrane protein bearing a fatty acid hydroxylase domain. This gene is expressed during symbiosis with M. pudica and requires NodD and luteolin for optimal expression. The closest noeM homologs formed a separate phylogenetic clade containing rhizobial genes only, which are located on symbiosis plasmids downstream from a nod box. Corresponding proteins, referred to as NoeM, may have specialized in symbiosis via the connection to the nodulation pathway and the spread in rhizobia. noeM was mostly found in isolates of the Mimoseae tribe, and specifically detected in all tested strains able to nodulate M. pudica. A noeM deletion mutant of C. taiwanensis was affected for the nodulation of M. pudica, confirming the role of noeM in the symbiosis with this legume.

Strain R2A43-10T was isolated from a greenhouse soil in Korea. Cells were Gram-negative rods, motile by means of a single flagellum. Growth occurred at 10–40 °C and at pH 5–8. Ubiquinone-8 (Q-8) was the only respiratory lipoquinone. Major fatty acids were summed feature 3 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH) and C16 : 0. 16S rRNA gene sequence analysis revealed that strain R2A43-10T was closely related to Chitinimonas taiwanensis cfT (sequence similarity of 94.8 %), but it exhibited low sequence similarities (<92 %) to other members of the Betaproteobacteria. The G+C content of the genomic DNA of strain R2A43-10T was 65.0 mol%. The novel isolate could be differentiated from C. taiwanensis cfT by several physiological properties. On the basis of genomic and phenotypic data, it is concluded that R2A43-10T (=KACC 11467T=DSM 17726T) is the type strain of a novel species of the genus Chitinimonas, for which the name Chitinimonas koreensis sp. nov. is proposed.

A novel Gram-negative, rod-shaped, motile, non-spore-forming bacterial strain, CMST, isolated from soil was characterized using phenotypic and molecular taxonomic methods. 16S rRNA gene sequence analysis revealed that the organism belongs phylogenetically to the genus Pseudomonas. Pseudomonas monteilii, P. plecoglossicida and P. mosselii were the most closely related species, with 16S rRNA gene sequence similarities to the respective type strains of 99.79, 99.73 and 99.59 %. Relatively low gyrB gene sequence similarities (<90 %) and DNA–DNA reassociation values (<51 %) were obtained between the strain and its phylogenetically closest neighbours. The G+C content of strain CMST was 62.7 mol%. The major cellular fatty acids were C18 : 1 ω7c, summed feature 3 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH), C16 : 0 and C10 : 0 3-OH. Based on the phenotypic and genetic evidence, the strain is suggested to represent a novel species, for which the name Pseudomonas taiwanensis sp. nov. is proposed. The type strain is CMST (=BCRC 17751T =DSM 21245T).

La symbiose qui s'établit entre les légumineuses et les bactéries appelées rhizobia est un processus complexe qui aboutit à la formation d'un nouvel organe végétal, le nodule, dans lequel les bactéries internalisées (bactéroïdes) fixent l'azote atmosphérique au profit de leur hôte. Les rhizobia ne constituent pas un groupe taxonomique homogène. Ils appartiennent à une quinzaine de genres dispersés au sein des α- and ß-protéobactéries. Les rhizobia auraient évolué à partir du transfert horizontal de gènes essentiels à la symbiose, suivi d'une réorganisation du génome d'accueil sous pression de sélection de la plante permettant une activation et/ou optimisation du potentiel symbiotique acquis. Ce scénario évolutif a été reproduit en laboratoire par une approche d'évolution expérimentale. Le plasmide symbiotique du symbiote de Mimosa pudica, Cupriavidus taiwanensis LMG19424, a été introduit dans la bactérie pathogène de plante Ralstonia solanacearum GMI1000. A partir de cette bactérie chimère 18 lignées parallèles ont été évoluées par des cycles successifs d'inoculation à M. pudica et ré-isolation des bactéries des nodules. Après 16 cycles d'évolution, trois observations ont été faites : i) les bactéries évoluées ne fixent pas l'azote et l'évolution vers le mutualisme n'est donc pas achevée à ce stade, ii) un gène de fonction inconnue semble important pour l'infection intracellulaire, et iii) les mutations permettant l'acquisition et/ou l'amélioration de l'infection des cellules du nodule semblent également améliorer la nodulation. Afin d'identifier les conditions favorables à l'émergence du mutualisme dans l'expérience d'évolution et potentiellement dans la nature, nous avons analysé la dynamique spatio-temporelle de deux sous-populations quasi isogéniques de C. taiwanensis, l'une fixatrice d'azote (Fix+) et l'autre non fixatrice (Fix-), au cours du processus symbiotique avec M. pudica. Nous avons observé une dégénérescence précoce et sélective des Fix-, y compris lorsqu'ils partagent un même nodule avec des Fix+, et établit la cinétique d'expansion des Fix+ au cours du temps. A partir d'un modèle mathématique et de validations expérimentales, nous avons prédit que de rares Fix+ envahiraient une population majoritairement Fix- au cours de cycles successifs de nodulation avec une probabilité fonction de la taille initiale de l'inoculum, du nombre de plantes inoculées et de la longueur des cycles. Par la suite nous avons étudié le rôle d'un gène du plasmide symbiotique de C. taiwanensis, dont la délétion dans l'une des lignées était responsable d'un défaut d'infection intracellulaire. Nous avons montré que ce gène, appelé noeM, est un gène de nodulation impliqué dans la biosynthèse de facteurs Nod atypiques où le sucre réducteur est ouvert et oxydé. noeM est principalement détecté dans des isolats de plantes appartenant à la tribu des Mimoseae, et particulièrement chez les souches capables de noduler M. pudica. Les gènes noeM forment un clade phylogénétique à part et spécifique des rhizobia. Un mutant ΔnoeM de C. taiwanensis s'est avéré affecté pour la nodulation de M. pudica, confirmant son rôle dans la symbiose avec cette légumineuse. Enfin, l'analyse cytologique détaillée de l'infection racinaire de M. pudica par C. taiwanensis et quelques souches de R. solanacearum portant une mutation adaptative de l'infection intracellulaire a été initiée, afin d'analyser l'impact de ces mutations sur les étapes symbiotiques précoces
The symbiosis between legumes and bacteria, known as rhizobia, is a complex process resulting in the formation of a novel plant organ, the nodule, in which internalized bacteria (bacteroids) fix nitrogen to the benefit of the host plant. Rhizobia do not form a homogeneous taxonomic group. They belong to a dozen of genera scattered within α- and ß-proteobacteria. Rhizobia may have evolved from horizontal transfer of key symbiotic genes, followed by genome remodeling under plant selection pressure, allowing the activation and/or optimization of the acquired symbiotic potential. This evolutionary scenario is being replayed in the laboratory using an experimental evolution approach. The symbiotic plasmid of the Mimosa pudica symbiont, Cupriavidus taiwanensis LMG19424, was introduced into the plant pathogen Ralstonia solanacearum GMI1000. 18 parallel lineages were derived from this chimeric ancestor using serial cycles of inoculation with M. pudica and re-isolation of bacteria from the nodules. After 16 cycles of evolution, three observations were done: i) the evolved bacteria do not fix nitrogen and evolution towards mutualism is not completed, ii) a gene of unknown function seems to be involved in intracellular infection and iii) the mutations that allow and/or improve intracellular infection also improve nodulation capacity. To determine conditions that favor the emergence of mutualism in the laboratory and possibly in nature, we analyzed the spatio-temporal dynamics of two quasi-isogenic sub-populations of C. taiwanensis, one nitrogen-fixing (Fix+) and the other not (Fix-), along their symbiotic process with M. pudica. We observed an early degenerescence of Fix- bacteroids, even when they share a nodule with Fix+, and established the kinetics of Fix+ expansion along time. Using mathematical modeling and experimental validations, we predicted that rare Fix+ will invade a population dominated by non-fixing bacteria during serial nodulation cycles with a probability that is function of initial inoculum, plant population size and nodulation cycle length. Then, we studied the role of a C. taiwanensis symbiotic plasmid gene, whose deletion in one lineage was responsible of intracellular infection defect. We showed that this gene, called noeM, is a novel nodulation gene involved in the biosynthesis of atypical Nod factors where the reducing sugar is open and oxidized. noeM was mostly found in isolates of the Mimoseae tribe, especially in all strains able to nodulate M. pudica. The noeM genes form a separate phylogenetic clade containing only rhizobial genes. A noeM deletion mutant of C. taiwanensis was affected for the nodulation of M. pudica confirming the role of noeM in the symbiosis with this legume. Last, we initiated the detailed cytological analysis of M. pudica root infection by C. taiwanensis and a few strains bearing adaptive mutations for intracellular infection, in order to analyze the effect of these mutations on early symbiotic stages