BackgroundMacropinocytosis, which is a constitutive cellular process of fluid and macromolecule uptake, is regulated by actin cytoskeleton rearrangements near the plasma membrane. Activation of Rac1, which is proposed to act upstream of the actin polymerization regulatory Wave 2 complex, has been found to correlate with enhanced macropinocytosis. One of the components of the Wave 2 complex is Abi1. Multiple, alternatively spliced isoforms of Abi1 are expressed in mammalian cells, but the functional significance of the various isoforms is unknown.Principal FindingsHere, using flow cytometric assay analysis for Alexa Fluor 647, we demonstrate that Abi1 isoforms 2 and 3 differentially regulate macropinocytosis. LNCaP cells expressing isoform 3 had increased macropinocytic uptake that correlated with enhanced cell spreading and higher Rac1 activation in comparison to cells expressing isoform 2. Isoform 2 expressing cells had decreased macropinocytic uptake, but demonstrated greater sensitivity to Rac1 activation. Moreover, more isoform 2 was localized within the cytoplasm in comparison to isoform 3, which was more associated with the plasma membrane. Activated Rac1 was found to specifically bind to a site in exon 10 of isoform 2 in vitro. Because of alternative mRNA splicing, exon 10 is absent from isoform 3, precluding similar binding of activated Rac1. Both isoforms, however, bound to inactive Rac1 through the same non-exon 10 site. Thus, Abi1 isoform 3-containing Wave 2 complex exhibited a differential binding to activated vs. inactive Rac1, whereas isoform 2-containing Wave 2 complex bound activated or inactive Rac1 comparably.ConclusionBased on these observations, we postulate that Abi1 isoforms differentially regulate macropinocytosis as a consequence of their different relative affinities for activated Rac1 in Wave 2 complex. These findings also raise the possibility that isoform-specific roles occur in other Abi1 functions.

The study compares morphology of clusters and fruits, the chemical composition and changes of pulp in the process of maceration of grape cultivars ‘Mavrud’, ‘Pinot Noir’ and ‘Merlot’. The cultivar ‘Mavrud’ had biggest clusters and fruits. Its fruits were less firm but had the highest acidity while the fruits of the ‘Pinot Noir’ had the highest content of soluble solids and dry matter and the greatest firmness but the lowest acidity and content of nitrites and nitrates. The fruits of the ‘Merlot’ cultivar had the highest content of L-ascorbic acid, nitrites and nitrates. The pulp colour was largely affected by the maceration temperature. During a warm maceration, the process of pulp darkening accelerated and the red colour saturation increased, whereas cold maceration resulted in the blue colour saturation.

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Study on the quality of wines produced from ‘Syrah’ and ‘Tempranillo’ cultivars planted in two microregions in Southern Bulgaria In the period 2006-2008 a comparative study was carried out on the ‘Tempranillo’, ‘Syrah 99’ and ‘Syrah 100’ cultivars, grown in two microregions in Southern Bulgaria - Brestnik and Pesnopoy. The soils in the region of Pesnopoy are of a better mechanical and chemical composition, which preconditions the formation of relatively high yields of good quality grapes. The ‘Tempranillo’ cultivar was highly productive in both microregions, however the quality of the wines was lower, compared to the ‘Syrah’ cultivar. They were poorer both in the content of extract and in fruit aroma. ‘Syrah 99’ from Brestnik and ‘Syrah 100’ clones from Pesnopoy do not differ significantly in productivity, but the wines of ‘Syrah 100’ from the Pesnopoy region were more intense in colour and their aroma was strong, full-bodied and lasting with dominating floral (violet) and forest fruit nuances. Tasting results showed high scores, which is evidence that the young wines have potential and contain the ingredients and components necessary to develop further into top quality red wines.

Vine undergoes seasonal changes repeated annually in a certain sequence. In the spring time, the shoots’ development and inflorescences begin, flowering occurs, and in the summer the berry size increases, after the grapes and shoots ripen. This period of active life is called the growing season. The main phenological stages duration: bud burst, first leaf appearance, first inflorescens appearance, flowering, bunch clossure and technological maturity (veraison) differ for each variety (clone). The length of the growing season for each variety is directly related to the vineyard location, air and soil temperature, soil moisture and management practices. This study aims to compare the main phenological stages and determine the differences between clones from the Syrah variety, regarding the influence of air temperature.