Sphingomonas cremea sp. nov., isolated from ginseng soil.

A novel Gram-stain-negative, aerobic, rod-shaped, non-motile, cream-coloured strain (G124T) was isolated from ginseng soil collected in Yeongju, Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain G124T belongs to a distinct lineage within the genus Sphingomonas (family Sphingomonadaceae, order Sphingomonadales and class Alphaproteobacteria). Strain G124T was closely related to Sphingomonas rhizophila THG-T61T (98.5 % 16S rRNA gene sequence similarity), Sphingomonas mesophila SYSUP0001T (98.3 %), Sphingomonas edaphi DAC4T (97.6 %) and Sphingomonas jaspsi TDMA-16T (97.6 %). The strain contained ubiquinone 10 as the major respiratory quinone. The major polar lipid profile of strain G124T comprised phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and sphingoglycolipids. The predominant cellular fatty acids of strain G124T were summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c; 33.4 %), summed feature 3 (C16 : 1 ω6c/C16 : 1 ω7c; 27.2 %) and C16 : 0 (18.3 %). The genome size of strain G124T was 2 549 305 bp. The genomic DNA G+C content is 62.0 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain G124T and other Sphingomonas species were in the range of 71.2-75.9 % and 18.7-19.9 %, respectively. Based on the polyphasic analysis such as biochemical, phylogenetic and chemotaxonomic characteristics, strain G124T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas cremea sp. nov. is proposed. The type strain is G124T (=KACC 21691T=LMG 31729T).

Unbiased Cell-based Screening in a Neuronal Cell Model of Batten Disease Highlights an Interaction between Ca2+ Homeostasis, Autophagy, and CLN3 Protein Function.

Abnormal accumulation of undigested macromolecules, often disease-specific, is a major feature of lysosomal and neurodegenerative disease and is frequently attributed to defective autophagy. The mechanistic underpinnings of the autophagy defects are the subject of intense research, which is aided by genetic disease models. To gain an improved understanding of the pathways regulating defective autophagy specifically in juvenile neuronal ceroid lipofuscinosis (JNCL or Batten disease), a neurodegenerative disease of childhood, we developed and piloted a GFP-microtubule-associated protein 1 light chain 3 (GFP-LC3) screening assay to identify, in an unbiased fashion, genotype-sensitive small molecule autophagy modifiers, employing a JNCL neuronal cell model bearing the most common disease mutation in CLN3. Thapsigargin, a sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) Ca(2+) pump inhibitor, reproducibly displayed significantly more activity in the mouse JNCL cells, an effect that was also observed in human-induced pluripotent stem cell-derived JNCL neural progenitor cells. The mechanism of thapsigargin sensitivity was Ca(2+)-mediated, and autophagosome accumulation in JNCL cells could be reversed by Ca(2+) chelation. Interrogation of intracellular Ca(2+) handling highlighted alterations in endoplasmic reticulum, mitochondrial, and lysosomal Ca(2+) pools and in store-operated Ca(2+) uptake in JNCL cells. These results further support an important role for the CLN3 protein in intracellular Ca(2+) handling and in autophagic pathway flux and establish a powerful new platform for therapeutic screening.

Highly selective hydrolysis for the outer glucose at the C-20 position in ginsenosides by ß-glucosidase from Thermus thermophilus and its application to the production of ginsenoside F2 from gypenoside XVII.

ß-Glucosidase from Thermus thermophilus has specific hydrolytic activity for the outer glucose at the C-20 position in protopanaxadiol-type ginsenosides without hydrolysis of the inner glucose. The hydrolytic activity of the enzyme for gypenoside XVII was optimal at pH 6.5 and 90 °C, with a half-life of 1 h with 3 g enzyme l(-1) and 4 g gypenoside XVII l(-1). Under the optimized conditions, the enzyme converted the substrate gypenoside XVII to ginsenoside F2 with a molar yield of 100 % and a productivity of 4 g l(-1) h(-1). The conversion yield and productivity of ginsenoside F2 are the highest reported thus far among enzymatic transformations.

Complete conversion of major protopanaxadiol ginsenosides to compound K by the combined use of α-L-arabinofuranosidase and ß-galactosidase from Caldicellulosiruptor saccharolyticus and ß-glucosidase from Sulfolobus acidocaldarius.

The ginsenoside compound K has pharmaceutical activities, including anti-tumor, anti-inflammatory, anti-allergic, and hepatoprotective effects. To increase the production of compound K, the α-L-arabinofuranoside-hydrolyzing α-L-arabinofuranosidase (CS-abf) and/or the α-L-arabinopyranoside-hydrolyzing ß-galactosidase from Caldicellulosiruptor saccharolyticus (CS-bgal) were mixed with the ß-D-glucopyranoside-hydrolyzing ß-glucosidase from Sulfolobus acidocaldarius (SA-bglu). The optimum conditions for the production of ginsenoside compound K from ginsenoside Rc or Rb2, or from major protopanaxadiol ginsenosides in ginseng root extract were determined to be pH 6.0 and 75°C with 8 mg ml⁻¹ ginsenoside Rc, 8 mg ml⁻¹ Rb2, or 10% (w/v) ginseng root extract; and 10.5 U ml⁻¹ CS-abf or CS-bgal supplemented with 4.5 U ml⁻¹ SA-bglu, or 10.5 U ml⁻¹ CS-abf and 10.5 U ml⁻¹ CS-bgal supplemented with 4.5 U ml⁻¹ SA-bglu, respectively. Under optimum conditions, ginsenosides Rc and Rb2, and major protopanaxadiol ginsenosides in ginseng root extract were completely converted to compound K after 12, 14, and 20 h, respectively, with the respective productivities of 388, 328, and 144 mg l⁻¹ h⁻¹. This is the first report of the complete conversion of major protopanaxadiol ginsenosides to compound K.