Salinity is a major constraint on rice productivity worldwide. However, mechanisms of salt tolerance in wild rice relatives are unknown. Root microsomal proteins are extracted from two Oryza australiensis accessions contrasting in salt tolerance.
View Article and Find Full Text PDFUnderstanding forest tree responses to climate warming and heatwaves is important for predicting changes in tree species diversity, forest C uptake, and vegetation-climate interactions. Yet, tree species differences in heatwave tolerance and their plasticity to growth temperature remain poorly understood. In this study, populations of four Eucalyptus species, two with large range sizes and two with comparatively small range sizes, were grown under two temperature treatments (cool and warm) before being exposed to an equivalent experimental heatwave.
View Article and Find Full Text PDFBackground: Grape cultivars and wines are distinguishable by their color, flavor and aroma profiles. Omic analyses (transcripts, proteins and metabolites) are powerful tools for assessing biochemical differences in biological systems.
Results: Berry skins of red- (Cabernet Sauvignon, Merlot, Pinot Noir) and white-skinned (Chardonnay, Semillon) wine grapes were harvested near optimum maturity (°Brix-to-titratable acidity ratio) from the same experimental vineyard.
Protein haze is an aesthetic problem in white wines that can be prevented by removing the grape proteins that have survived the winemaking process. The haze-forming proteins are grape pathogenesis-related proteins that are highly stable during winemaking, but some of them precipitate over time and with elevated temperatures. Protein removal is currently achieved by bentonite addition, an inefficient process that can lead to higher costs and quality losses in winemaking.
View Article and Find Full Text PDFGrape thaumatin-like proteins (TLPs) play roles in plant-pathogen interactions and can cause protein haze in white wine unless removed prior to bottling. Different isoforms of TLPs have different hazing potential and aggregation behavior. Here we present the elucidation of the molecular structures of three grape TLPs that display different hazing potential.
View Article and Find Full Text PDFThe juice used to make white wine can be extracted using various physical processes that affect the amount and timing of contact of juice with skins. The influence of juice extraction processes on the mouthfeel and taste of white wine and their relationship to wine composition were determined. The amount and type of interaction of juice with skins affected both wine total phenolic concentration and phenolic composition.
View Article and Find Full Text PDFWhite wines suffer from heat-induced protein hazes during transport and storage unless the proteins are removed prior to bottling. Bentonite fining is by far the most commonly used method, but it is inefficient and creates several other process challenges. An alternative to bentonite is the enzymatic removal of haze-forming grape pathogenesis-related proteins using added proteases.
View Article and Find Full Text PDFHistorically many genome annotation strategies have lacked experimental evidence at the protein level, which and have instead relied heavily on ab initio gene prediction tools, which consequently resulted in many incorrectly annotated genomic sequences. Proteogenomics aims to address these issues using mass spectrometry (MS)-based proteomics, genomic mapping, and providing statistical significance measures such as false discovery rates (FDRs) to validate the mapped peptides. Presented here is a tool capable of meeting this goal, the UCSD proteogenomic pipeline, which maps peptide-spectrum matches (PSMs) to the genome using the Inspect MS/MS database search tool and assigns a statistical significance to the match using a target-decoy search approach to assign estimated FDRs.
View Article and Find Full Text PDFLow root temperature causes a decrease in water uptake, which leads to mineral and nutrient deficiencies with potentially decreased root and shoot growth. Differential temperature effects in plants have been studied extensively, however, the effect of root chilling on the global protein expression in shoots has not been explored. In this study, we imposed chilling temperatures on roots of rice plants while maintaining shoots at optimum atmospheric temperature.
View Article and Find Full Text PDFResidual proteins in finished wines can aggregate to form haze. To obtain insights into the mechanism of protein haze formation, a reconstitution approach was used to study the heat-induced aggregation behavior of purified wine proteins. A chitinase, four thaumatin-like protein (TLP) isoforms, phenolics, and polysaccharides were isolated from a Chardonnay wine.
View Article and Find Full Text PDFBentonite is commonly used to remove grape proteins responsible for haze formation in white wines. Proteases potentially represent an alternative to bentonite, but so far none has shown satisfactory activity under winemaking conditions. A promising candidate is AGP, a mixture of Aspergillopepsins I and II.
View Article and Find Full Text PDFIn this review we examine techniques, software, and statistical analyses used in label-free quantitative proteomics studies for area under the curve and spectral counting approaches. Recent advances in the field are discussed in an order that reflects a logical workflow design. Examples of studies that follow this design are presented to highlight the requirement for statistical assessment and further experiments to validate results from label-free quantitation.
View Article and Find Full Text PDFGrape chitinase was found to be the primary cause of heat-induced haze formation in white wines. Chitinase was the dominant protein in a haze induced by treating Sauvignon blanc wine at 30 °C for 22 h. In artificial wines and real wines, chitinase concentration was directly correlated to the turbidity of heat-induced haze formation (50 °C for 3 h).
View Article and Find Full Text PDFA thermal unfolding study of thaumatin-like protein, chitinase, and invertase isolated from Vitis vinifera Sauvignon blanc and Semillon juice was undertaken. Differential scanning calorimetry demonstrated that chitinase was a major player in heat-induced haze in unfined wines as it had a low melt temperature, and aggregation was observed. The kinetics of chitinase F1 (Sauvignon blanc) unfolding was studied using circular dichroism spectrometry.
View Article and Find Full Text PDFGrape thaumatin-like (TL) proteins and chitinases play roles in plant-pathogen interactions and can cause protein haze in white wine unless removed prior to bottling. A two-step method is described that highly purified hundreds of milligrams of TL proteins and chitinases from two juices by strong cation exchange (SCX) and hydrophobic interaction chromatography (HIC). The method was fast and separated isoforms of TL proteins and chitinases from within the same juice, in most cases to >97% purity.
View Article and Find Full Text PDFThe ascomycete plant pathogen Botrytis cinerea secretes aspartic proteinase (AP) activity. Functional analysis was carried out on five aspartic proteinase genes (Bcap1-5) reported previously. Single and double mutants lacking these five genes showed neither a reduced secreted proteolytic activity, nor a reduction in virulence and they showed no alteration in sensitivity to antifungal proteins purified from grape juice.
View Article and Find Full Text PDFA method to fractionate grape and wine proteins by hydrophobic interaction chromatography (HIC) was developed. This method allowed the isolation of a thaumatin-like protein in a single step with high yield and >90% purity and has potential to purify several other proteins. In addition, by separating HIC fractions by reverse phase HPLC and by collecting the obtained peaks, the grape juice proteins were further separated, by SDS-PAGE, into 24 bands.
View Article and Find Full Text PDF