Cellular change and callose accumulation in zygotic embryos of Eleutherococcus senticosus caused by plasmolyzing pretreatment result in high frequency of single-cell-derived somatic embryogenesis

Summary. Eleutherococcus senticosus zygotic embryos were pretreated with 1.0 M mannitol or sucrose for 3–24 h. This pretreatment resulted in a high frequency of somatic-embryo formation on hormone-free medium. All the somatic embryos developed directly and independently from single epidermal cells on the surface of zygotic embryos after plasmolyzing pretreatment. Scanning electron microscopic observation revealed that the epidermal cells of hypocotyls rapidly became irregular and showed a random orientation before somatic-embryo development commenced. At the same time, the epidermal cells in the untreated control remained regular. Callose concentration determined by fluorometric analysis increased sharply in E. senticosus zygotic embryos after plasmolyzing pretreatment but remained low in the untreated control. Aniline blue fluorescent staining of callose showed that the plasmolyzing pretreatment of zygotic embryos resulted in heavy accumulation of callose between the plasma membrane and cell walls. On the basis of these results, we suggest that plasmolyzing pretreatment of zygotic embryos induces the accumulation of callose, and the interruption of cell-to-cell communication imposed by this might stimulate the reprogramming of epidermal cells into embryogenically competent cells and finally induce somatic-embryo development from single cells. Correspondence and reprints: Division of Forest Resources, College of Forest Sciences, Kangwon National University, Chunchon 200-701, Republic of Korea.     

Design, synthesis and biological evaluation of 2-(substituted phenyl)thiazolidine-4-carboxylic acid derivatives as novel tyrosinase inhibitors

Herein we describe the design, synthesis and biological activities of 2-(substituted phenyl)thiazolidine-4-carboxylic acid derivatives as novel tyrosinase inhibitors. The target compounds 2a–2j were designed and synthesized from the structural characteristics of N-phenylthiourea, tyrosinase inhibitor and tyrosine, and l-DOPA, the natural substrates of tyrosinase. Among them, (2R/S,4R)-2-(2,4-dimethoxyphenyl)thiazolidine-4-carboxylic acid (2g) caused the greatest inhibition 66.47% at 20 μM of l-DOPA oxidase activity of mushroom tyrosinase. Kinetic analysis of tyrosinase inhibition revealed that 2g is a competitive inhibitor. We predicted the tertiary structure of tyrosinase, and simulated the docking of mushroom tyrosinase with 2g. These results suggest that the binding affinity of 2g with tyrosinase is high. Also, 2g effectively inhibited tyrosinase activity and reduced melanin levels in B16 cells treated with α-MSH. These data strongly suggest that 2g can suppress the production of melanin via the inhibition of tyrosinase activity.     

Identification of somaclonal variants in proliferating shoot cultures of Senecio cruentus cv. Tokyo Daruma

A protocol for in vitro propagation of cineraria (Senecio cruentus) was developed. The highest frequency of shoot proliferation was obtained from nodal explants cultured on Murashige and Skoog (MS) medium supplemented with 2.0?mg L^?1 6-benzyladenine (BA) and 0.5?mg L^?1 ??-naphthalene acetic acid (NAA), with a mean number of 14 shoots per explant. A high concentration of BA (4.0?mg L^?1) and repeated subcultures resulted in hyperhydric shoots. Decreasing the BA concentration to 1.0?mg L^?1 in the culture medium eliminated hyperhydricity. The concentration of ammonium nitrate (NH₄NO₃) and temperature had marked effects on somaclonal variation. Variation was observed when the cultures were maintained at 15?°C but not at 25?°C. Variants with blue-colored leaves and stems were identified; whereas, normal plants maintained their green-colored leaves and stems. The highest frequency of variation (67.5?%), with a mean number of 3.0 variant shoots per explants, was obtained on shoot proliferation medium (MS?+?2.0?mg L^?1 BA and 0.5?mg L^?1 NAA) devoid of NH₄NO₃. The best rooting (100?%), with the highest number of roots per shoot (10.8) and the greatest root length (6.8?cm) was obtained on medium supplemented with 0.1?mg L^?1 NAA. In vitro-grown plantlets were successfully acclimatized in a greenhouse, and transferred to the field.     

Genome sequence of the probiotic bacterium Sporolactobacillus vineae SL153T

The novel Sporolactobacillus vineae SL153(T) strain has excellent intestinal adherence and growth inhibitory effect on pathogenic microorganisms, including Vibrio genus microorganisms, and therefore can be effectively used for the prevention and treatment of disease caused by pathogenic microorganisms. Here, we first report the draft genome sequence of a novel species in the genus Sporolactobacillus.     

Genome sequence of Lactobacillus fructivorans KCTC 3543

Lactobacillus fructivorans is important in the generation of particular flavors and in other ripening processes associated with fermented food. Here, we present the draft genome sequence of the type strain Lactobacillus fructivorans KCTC 3543 (1,373,326 bp, with a G+C content of 38.9%), which consists of 5 scaffolds. The genome sequence was obtained by using a whole-genome shotgun strategy with Roche 454 GS (FLX Titanium) pyrosequencing, and all of the reads were assembled using Newbler Assembler 2.3.     

Synthesis of novel azo-resveratrol,azo-oxyresveratrol and their derivatives as potent tyrosinase inhibitors

Ten azo compounds including azo-resveratrol (5) and azo-oxyresveratrol (9) were synthesized using a modified Curtius rearrangement and diazotization followed by coupling reactions with various phenolic analogs. All synthesized compounds were evaluated for their mushroom tyrosinase inhibitory activity. Compounds 4 and 5 exhibited high tyrosinase inhibitory activity (56.25% and 72.75% at 50 μM, respectively). The results of mushroom tyrosinase inhibition assays indicate that the 4-hydroxyphenyl moiety is essential for high inhibition and that 3,5-dihydroxyphenyl and 3,5-dimethoxyphenyl derivatives are better for tyrosinase inhibition than 2,5-dimethoxyphenyl derivatives. Particularly, introduction of hydroxyl or methoxy group into the 4-hydroxyphenyl moiety diminished or significantly reduced mushroom tryosinase inhibition. Among the synthesized azo compounds, azo-resveratrol (5) showed the most potent mushroom tyrosinase inhibition with an IC₅₀ value of IC₅₀ = 36.28 ± 0.72 μM, comparable to that of resveratrol, a well-known tyrosinase inhibitor.     

Genome analysis of the domestic dog (Korean Jindo) by massively parallel sequencing

Although pioneering sequencing projects have shed light on the boxer and poodle genomes, a number of challenges need to be met before the sequencing and annotation of the dog genome can be considered complete. Here, we present the DNA sequence of the Jindo dog genome, sequenced to 45-fold average coverage using Illumina massively parallel sequencing technology. A comparison of the sequence to the reference boxer genome led to the identification of 4 675 437 single nucleotide polymorphisms (SNPs, including 3 346 058 novel SNPs), 71 642 indels and 8131 structural variations. Of these, 339 non-synonymous SNPs and 3 indels are located within coding sequences (CDS). In particular, 3 non-synonymous SNPs and a 26-bp deletion occur in the TCOF1 locus, implying that the difference observed in cranial facial morphology between Jindo and boxer dogs might be influenced by those variations. Through the annotation of the Jindo olfactory receptor gene family, we found 2 unique olfactory receptor genes and 236 olfactory receptor genes harbouring non-synonymous homozygous SNPs that are likely to affect smelling capability. In addition, we determined the DNA sequence of the Jindo dog mitochondrial genome and identified Jindo dog-specific mtDNA genotypes. This Jindo genome data upgrade our understanding of dog genomic architecture and will be a very valuable resource for investigating not only dog genetics and genomics but also human and dog disease genetics and comparative genomics.