Study of Chitinase and Chitinolytic Activity of Lactobacillus Strains

The increasing consumer demand for less processed and more natural food products - while improving those products’ quality, safety, and shelf-life – has raised the necessity of chemical preservative replacement. Biopreservation refers to extended storage life and enhanced safety of foods using the natural microflora and (or) their antibacterial products. Chitinolytic enzymes are of biotechnological interest, since their substrate, chitin, is a major structural component of the cell wall of fungi, which are the main cause of the spoilage of food and raw plant material. Among the several organisms, many bacteria produce chitinolytic enzymes, however, this behaviour is not general. The chitinase activity of the lactic acid bacteria is scarcely known and studied. The aim of the present study was to select Lactobacillus strains that have genes encoding chitinase, furthermore, to detect expressed enzymes and to characterise their chitinase activity. Taking into consideration the importance of chitin-bindig proteins (CBPs) in the chitinase activity, CBPs were also examined. Five Lactobacillus strains out of 43 strains from 12 different species were selected by their chitinase coding gene. The presence of the chitinase and chitin-biding protein production were confirmed, however, no chitinolytic activity has been identified

Proteomic analysis of pollination-induced corolla senescence in petunia

Senescence represents the last phase of petal development during which macromolecules and organelles are degraded and nutrients are recycled to developing tissues. To understand better the post-transcriptional changes regulating petal senescence, a proteomic approach was used to profile protein changes during the senescence of Petunia×hybrida ‘Mitchell Diploid’ corollas. Total soluble proteins were extracted from unpollinated petunia corollas at 0, 24, 48, and 72 h after flower opening and at 24, 48, and 72 h after pollination. Two-dimensional gel electrophoresis (2-DE) was used to identify proteins that were differentially expressed in non-senescing (unpollinated) and senescing (pollinated) corollas, and image analysis was used to determine which proteins were up- or down-regulated by the experimentally determined cut-off of 2.1-fold for P <0.05. One hundred and thirty-three differentially expressed protein spots were selected for sequencing. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine the identity of these proteins. Searching translated EST databases and the NCBI non-redundant protein database, it was possible to assign a putative identification to greater than 90% of these proteins. Many of the senescence up-regulated proteins were putatively involved in defence and stress responses or macromolecule catabolism. Some proteins, not previously characterized during flower senescence, were identified, including an orthologue of the tomato abscisic acid stress ripening protein 4 (ASR4). Gene expression patterns did not always correlate with protein expression, confirming that both proteomic and genomic approaches will be required to obtain a detailed understanding of the regulation of petal senescence

Identification of heat shock proteins from bacteria by electrophoretic separation and nanoflow LC-MS/MS. Preliminary communication

Examination of heat shock and PR (“pathogenesis-related”) proteins is of special interest in food science. Many food allergens have a similar or the same structure as PR proteins, which are produced in the plants as a response to pathogenesis or certain environmental stresses. The protein set of the psychrophilic bacterium Shewanella hanedai was studied by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Gel patterns from control and heat-treated bacteria were evaluated by PDQUEST software. The differentially expressed proteins were excised from the gel and digested by trypsin. The tryptic peptides were analysed by nanoflow LC-MS/MS. On the basis of amino acid sequences obtained by this method, the proteins were identified by similarity searching in the protein database. Using this proteomic approach a heat shock and a 50S ribosomal protein were identified as the major heat induced proteins in Shewanella hanedai

Changes in total- and α -amylase activities and wheat germ agglutinin content in wide-range herbicide resistant wheat lines

Protein sets, enzyme activities and immune reactivity against wheat germ agglutinin in the albumin-globulin fractions of parent and herbicide resistant transgenic wheat lines were studied.Our results showed significantly increased amylase activities and increased immune reactivity against wheat germ agglutinin in the herbicide resistant transgenic wheat lines, investigated. The amylases and lectins belong to the plant food allergens; this explains why both scientists and consumers are interested in assessing the allergenic potential of plant proteins and the safety assessment of novel foods and GM foods in highlight of food safety. This paper is an important contribution to our database and the understanding of what is going on with genetic engineering of crop plants