Caracterización molecular de los microorganismos presentes durante el proceso fermentativo de los granos de cacao (Theobroma cacao) / Molecular characterization of microorganisms during cocoa-bean fermentation process (Theobroma cacao)

La fermentación de granos de cacao es un proceso espontáneo de post cosecha muy importante para el desarrollo de aroma y sabor a chocolate el cual involucra un sin número de actividades microbianas complejas. En el presente estudio se identifican los microorganismos presentes en granos de cacao antes, durante y después del proceso de fermentación aplicando dos métodos: el análisis de secuenciamiento de ADN y la espectrometría de masas MALDI TOF/TOF. Dentro del grupo de bacterias y levaduras predominantes identificadas por el primer método se encontro a Lactobacillus plantarum (29%), L. brevis (18%), Bacillus cereus (15%), Pediococcus acidilactici (12%), y Pichia kudriavzevii (100%). Asimismo se caracterizó por huella de masas las secuencias peptídicas más importantes de cada cepa identificada. Por otro lado, aplicando el segundo método, se identificaron 57 especies de microorganismos, siendo el 73.7% especies bacterianas y el 26.3% especies de levaduras. Adicionalmente se detectaron secuencias peptídicas de la proteína vicilina responsable del aroma característico de los granos de cacao fermentados y a la proteína albumina de 21KDa.

Cocoa beans fermentation is a spontaneous process of post-harvest very important for the development of chocolate aroma and flavor, which involves a number of complex microbial activities. In this work, we identify the microorganisms present in cocoa beans before, during and after the fermentation process, applying DNA sequencing analysis and MALDI TOF / TOF mass spectrometry. With the first method, the predominant bacteria and yeast identified were Lactobacillus plantarum (29%), L. brevis (18%), Bacillus cereus (15%), Pediococcus acidilactici (12%), and Pichia kudriavzevii (100%). The most important peptide sequences of each identified strain by mass fingerprint were characterized too. By the second method, 51 species of microorganisms being 73.7% bacterial species and 26.3% yeast species were identified. Additionally peptide sequences responsible Vicilin protein characteristic aroma of the fermented cocoa beans and the albumin protein of 21KDa were detected.

Proteomic analysis of the regenerating liver following 2/3 partial hepatectomy in rats

BACKGROUND: Liver regeneration (LR) after 2/3 partial hepatectomy (PH) is one of the most studied models of cell, organ, and tissue regeneration. Although the transcriptional profile analysis of regenerating liver has been carried out by many reserachers, the dynamic protein expression profile during LR has been rarely reported up to date. Therefore, this study aims to detect the global proteomic profile of the regenerating rat liver following 2/3 hepatectomy, thereby gaining some insights into hepatic regeneration mechanism. RESULTS: Protein samples extracted from the sham-operated and the regenerating rat livers at 6, 12, 24, 72, 120 and 168 h after PH were separated by IEF/SDS-PAGE and then analyzed by MALDI-TOF/TOF mass spectrometry. Compared to sham-operated groups, there were totally 220 differentially expressed proteins (including 156 up-regulated, 62 down-regulated, and 2 up/down-regulated ones) identified in the regenerating rat livers, and most of them have not been previously related to liver regeneration. According to the expression pattern analysis combined with gene functional analysis, it showed that lipid and carbohydrate metabolism were enhanced at the early phase of LR and continue throughout the regeneration process. Ingenuity Pathway Analysis indicated that YWHAE protein (one of members of the 14-3-3 protein family) was located at the center of pathway networks at all the timepoints after 2/3 hepatectomy under our experimental conditions, maybe suggesting a central role of this protein in regulating liver regeneration. Additionally, we also revealed the role of Cdc42 (cell division cycle 42) in the termination of LR. CONCLUSIONS: For the first time, our proteomic analysis suggested an important role of YWHAE and pathway mediated by this protein in liver regeneration, which might be helpful in expanding our understanding of LR amd unraveling the mechanisms of LR.

Analysis of Proteomic Components of Sera from Patients with Uremia by Two Dimensional Electrophoresis and Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry / 华中科技大学学报（医学）（英德文版）

The different sera proteomic components between uremia patients and normal subjects were studied through two-dimensional gel electrophoresis technique. Immobilized pH gradient twodimensional polyacrylamide gel electrophoresis (2DE), silver staining, ImageMaster 2D 5.0 analysis software, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDITOF-TOF-MS) and IPI human database searching were used to separate and identify the proteome of the sera from the patients with uremia. The results showed that satisfactory 2DE patterns of the serum proteins were obtained. Twenty-six protein spots showed significant difference in quantity in uremia patients, and 20 protein spots were identified by MALDI-TOF-TOF-MS. It was concluded that good reproducibility could be obtained by applying immobilized pH gradient 2DE to separate and identify the proteome in serum, which provided the foundation for the further study on uremia toxins pertaining to protein.