Crossostephium

Abstract: A Gram-negative, coccoid-shaped bacterium, strain CC-CCM15-8T, was isolated from a rhizosphere soil sample of the plant Crossostephium chinense (L.) Makino (Seremban) from Budai Township, Chiayi County, Taiwan. 16S rRNA gene sequence analysis clearly allocated strain CC-CCM15-8T to the Paracoccus cluster, showing highest similarities to the type strains of ‘Paracoccus beibuensis’ (98.8 %), Paracoccus homiensis (97.6 %), Paracoccus aestuarii (97.7 %) and Paracoccus zeaxanthinifaciens (97.7 %). The fatty acid profile, comprising C18 : 1ω7c as the major component and C10 : 0 3-OH as the characteristic hydroxylated fatty acid, supported the placement of strain CC-CCM15-8T within the genus Paracoccus . The polyamine pattern consisted of putrescine and spermidine as major components. Ubiqinone Q-10 was the major quinone type (95 %); ubiquinone Q-9 was also detected (5 %). The complex polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, and unidentified phospholipids, lipids and glycolipids. Levels of DNA–DNA relatedness between strain CC-CCM15-8T and ‘P. beibuensis’ LMG 25871T, P. aestuarii DSM 19484T, P. zeaxanthinifaciens LMG 21993T and P. homiensis KACC 11518T were 24.9 % (34.8 %, reciprocal analysis), 15.7 % (17.5 %), 17.7 % (23.4 %) and 16.0 % (25.4 %), respectively. Physiological and biochemical test results allowed the phenotypic differentiation of strain CC-CCM15-8T from its closest relatives in the genus Paracoccus . Based on the data presented, it is concluded that strain CC-CCM15-8T represents a novel species of the genus Paracoccus , for which the name Paracoccus rhizosphaerae sp. nov. is proposed. The type strain is CC-CCM15-8T ( = LMG 26205T = CCM 7904T).

Abstract: Soil salinization is becoming a limitation to the utilization of ornamental plants worldwide. Crossostephium chinensis (Linnaeus) Makino is often cultivated along the southeast coast of China for its desirable ornamental qualities and high salt tolerance. However, little is known about the genomic background of the salt tolerance mechanism in C. chinensis. In the present study, we used Illumina paired-end sequencing to systematically investigate leaf transcriptomes derived from C. chinensis seedlings grown under normal conditions and under salt stress. A total of 105,473,004 bp of reads were assembled into 163,046 unigenes, of which 65,839 (40.38% of the total) and 54,342 (33.32% of the total) were aligned in Swiss-Prot and Nr protein, respectively. A total of 11,331 (6.95%) differentially expressed genes (DEGs) were identified among three comparisons, including 2,239 in 'ST3 vs ST0', 5,880 in 'ST9 vs ST3' and 9,718 in 'ST9 vs ST0', and they were generally classified into 26 Gene Ontology terms and 58 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway terms. Many genes encoding important transcription factors (e.g., WRKY, MYB, and AP2/EREBP) and proteins involved in starch and sucrose metabolism, arginine and proline metabolism, plant hormone signal transduction, amino acid biosynthesis, plant-pathogen interactions and carbohydrate metabolism, among others, were substantially up-regulated under salt stress. These genes represent important candidates for studying the salt-response mechanism and molecular biology of C. chinensis and its relatives. Our findings provide a genomic sequence resource for functional genetic assignments in C. chinensis. These transcriptome datasets will help elucidate the molecular mechanisms responsible for salt-stress tolerance in C. chinensis and facilitate the breeding of new stress-tolerant cultivars for high-saline areas using this valuable genetic resource.

Abstract: OBJECTIVE To investigate the chemical constituents of 70% aqueous ethanol extract from the whole plant of Crossostephium chinense for inhibitory activity against alpha-glucosidase. METHOD A bioactivity-guided isolation and purification process was used to identify the alpha-glucosidase activity inhibiting components of the whole plant of C. chinense. The dried whole plants were extracted with 70% aqueous ethanol. The extract was suspended in water and then further fractionated successively with cyclohexane, ethyl acetate, and normal butanol,and tested for their inhibitory activity against alpha-glucosidase in vitro. The chemical structures of isolated compounds were determined by spectroscopic methods including NMR and MS, and comparison with data of authentic samples. All of compounds were assayed for their inhibitory activity against alpha-glucosidase in vitro. RESULT The ethyl acetate and water layer fractions showed the strong inhibitory activity, and were subjected to column chromatography over the various stationary phases. Tricetin 3',4',5'-trimethylether (1), scopoletin (2), tanacetin, hispidulin (3), apometzgerin (4), chrysoeriol (5), quercetagetin 3,6, 7-trimethylether (6), selagin (7) , scopolin (8), and quercetagetin-3,6-dimethylether (9) were isolated and characterized by different spectroscopic techniques. Among them, compounds 2, 3, 5-7 and 9 for inhibitory activity against alpha-glucosidase with IC50 (micromol x L(-1)) values of (34.36 +/- 2.06), (146.28 +/- 12.44), (246.26 +/- 8.73), (74.06 +/- 3.83), (42.19 +/- 5.25) and (136.20 +/- 25.73), respectively, were assayed as the active components. A positive drug, acarbose, showed the inhibitory activity against alpha-glucosidase with IC50 value of (489.25 +/- 38.55) mciromol x L(-1) in the same assay conditions with the above test com-1) pounds. The IC50 values of compounds 1, 4, 8 and tanacetin were all more than 1 000 micromol x L(-1). CONCLUSION The compounds 5 and 9 were isolated from the genus Crossostephium for the first time. The compounds 2, 3, 5-7, and 9 showed the strong inhibitory activity against alpha-glucosidase in vitro in the simple competitive manner. The results indicated that these compounds may be involved in the treatment of diabetes in the whole plant of C. chinense for human.