Protein Transmission, Seeding and Degradation: Key Steps for alpha-Synuclein Prion-Like Propagation

Converging lines of evidence suggest that cell-to-cell transmission and the self-propagation of pathogenic amyloidogenic proteins play a central role in the initiation and the progression of several neurodegenerative disorders. This "prion-like" hypothesis has been recently reported for alpha-synuclein, a presynaptic protein implicated in the pathogenesis of Parkinson's disease (PD) and related disorders. This review summarizes recent findings on alpha-synuclein prion-like propagation, focusing on its transmission, seeding and degradation and discusses some key questions that remain to be explored. Understanding how alpha-synuclein exits cells and propagates from one brain region to another will lead to the development of new therapeutic strategies for the treatment of PD, aiming at slowing or stopping the disease progression.

The Proteomic Analysis of Extracellular Proteins from Culture Filtrates of Dermatophytes / 대한의진균학회지

BACKGROUND: Proteases from dermatophytes have an important role in pathogenicity of these fungi as they facilitate penetration and colonization in the keratin structures of the stratum corneum, nails, and hair. Since the 1960s, efforts have been made to isolate and purify these enzymes, shedding light on hydrolytic properties and other characteristics of these extracellular proteins. It is now well known that under certain conditions, various proteases are produced which possess the capacity to digest casein, collagen, elastin, bovine serum albumin, hair, and keratin, while specific nature of these enzymes still remains to be elucidated. OBJECTIVE: We aimed to draw a proteome map of extracellular proteins from common dermatophytes using 2-dimensional electrophoresis, thus verifying the nature and interspecies differences in composition of extracellular proteins. METHODS: Following strains of dermatophytes were isolated from patients who visited the dermatologic outpatient clinic of Severance hospital and subcultured for 2 weeks on Sabouraud's dextrose agar: 2 strains of Trichophyton rubrum, 2 T. mentagrophytes, and 2 Microsporum canis. For growth media, glucose-peptone broth was added to each strain and 10 ml of media was taken, filtered using a 0.4micrometer syringe filter and the protein content obtained was concentrated by an ultrafiltration device before electrophoresis on the culture day 0 and 10. Stained with silver nitrate, the gel was scanned and analysed. RESULTS: 7 spots have increased in intensity including a 16 kDa-spot with isoelectric point at 9.3 from the supernatants of M. canis culture media, 4 spots have increased including a 32 kDa-spot with isoelectric point at 6.7, from the supernatants of T. mentagrophytes, and 5 spots including a 10 kDa-spot with isoelectric point at 6.3 showed significant increase from the supernatants of T. rubrum. M. canis and T. mentagrophytes subspecies shared 2 spots that increased. CONCLUSION: We concluded dermatophyte fungi produce different proteins according to their subspecies, and that proteomics appears to be a useful tool for comparative analysis of dermatophyte extracellular proteins.

Embryogenesis in flowering plants: Recent approaches and prospects.

The overall architectural pattern of the mature plant is established during embryogenesis. Very little is known about the molecular processes that underlie embryo morphogenesis. Last decade has, nevertheless, seen a burst of information on the subject. The synchronous somatic embryogenesis system of carrot is largely being used as the experimental system. Information on the molecular regulation of embryogenesis obtained with carrot somatic embryos as well as observations on sandalwood embryogenic system developed in our laboratory are summarized in this review. The basic experimental strategy of molecular analysis mostly relied on a comparison between genes and proteins being expressed in embryogenic and non-embryogenic cells as well as in the different stages of embryogenesis. Events such as expression of totipotency of cells and establishment of polarity which are so critical for embryo development have been characterized using the strategy. Several genes have been identified and cloned from the carrot system. These include sequences that encode certain extracellular proteins (EPs) that influence cell proliferation and embryogenesis in specific ways and sequences of the abscisic acid (ABA) inducible late embryogenesis abundant (LEA) proteins which are most abundant and differentially expressed mRNAs in somatic embryos. That LEAs are expressed in the somatic embryos of a tree flora also is evidenced from studies on sandalwood. Several undescribed or novel sequences that are enhanced in embryos were identified. A sequence of this nature exists in sandalwood embryos was demonstrated using a Cuscuta haustorial (organspecific) cDNA probe. Somatic embryogenesis systems have been used to assess the expression of genes isolated from non-embryogenic tissues. Particular attention has been focused on both cell cycle and histone genes.