Search results for "invertase"

Stimulation of Defense Reactions in Medicago truncatula by Antagonistic Lipopeptides from Paenibacillus sp. Strain B2

2010

ABSTRACT With the aim of obtaining new strategies to control plant diseases, we investigated the ability of antagonistic lipopolypeptides (paenimyxin) from Paenibacillus sp. strain B2 to elicit hydrogen peroxide (H 2 O 2 ) production and several defense-related genes in the model legume Medicago truncatula . For this purpose, M. truncatula cell suspensions were used and a pathosystem between M. truncatula and Fusarium acuminatum was established. In M. truncatula cell cultures, the induction of H 2 O 2 reached a maximum 20 min after elicitation with paenimyxin, whereas concentrations higher than 20 μM inhibited H 2 O 2 induction and this was correlated with a lethal effect. In plant roots in…

Changes in carbohydrate metabolism in Plasmopara viticola-infected grapevine leaves.

2011

International audience; The oomycete Plasmopara viticola is responsible for downy mildew, a severe grapevine disease. In infected grapevine leaves, we have observed an abnormal starch accumulation at the end of the dark period, suggesting modifications in starch metabolism. Therefore, several complementary approaches, including transcriptomic analyses, measurements of enzyme activities, and sugar quantification, were performed in order to investigate and to understand the effects of P. viticola infection on leaf starch and-to a larger extent-carbohydrate metabolism. Our results indicate that starch accumulation is associated with an increase in ADP-glucose pyrophosphorylase (AGPase) activit…

Gene regulatory networks elucidating Huanglongbing disease mechanisms

2013

Next-generation sequencing was exploited to gain deeper insight into the response to infection by Candidatus liberibacter asiaticus (CaLas), especially the immune disregulation and metabolic dysfunction caused by source-sink disruption. Previous fruit transcriptome data were compared with additional RNA-Seq data in three tissues: immature fruit, and young and mature leaves. Four categories of orchard trees were studied: symptomatic, asymptomatic, apparently healthy, and healthy. Principal component analysis found distinct expression patterns between immature and mature fruits and leaf samples for all four categories of trees. A predicted protein - protein interaction network identified HLB-…

Carbohydrate availability affects growth and metabolism in peach fruit

2008

Along with sucrose, sorbitol represents the main photosynthetic product and form of translocated carbon in peach. This study aimed at determining whether peach fruit carbohydrate metabolism is affected by changes in source-sink balance, and specifically whether sorbitol or sucrose availability regulates fruit enzyme activities and growth. In various trials, different levels of assimilate availability to growing fruits were induced in vivo, by varying crop load of entire trees, leaf:fruit ratio (L:F) of fruiting shoots, or by interrupting the phloem stream (girdling) to individual fruits. In vitro, fruit tissue was incubated in presence/absence of sorbitol and sucrose. Relative growth rate (…

Multiple copies of SUC4 regulatory regions may cause partial de-repression of invertase synthesis in Saccharomyces cerevisiae.

1992

Transformation to generate multiple copies of regulatory DNA sequences has been used to study the interactions between regulatory proteins and their target sequences, since a high copy number of these sequences may titrate trans-acting regulatory proteins. We have analyzed the synthesis of invertase in yeast strains carrying different SUC genes transformed with the multiple-copy plasmid pSH143, a derivative of pJDB207 containing the promoter and upstream regulatory sequences of SUC4. The results obtained seem to be strain dependent. Under repressing conditions a high copy number of SUC4 promoter regions may cause increased expression of the invertase genes resulting in the synthesis of exte…

Molecular events associated with glucose repression of invertase in Saccharomyces cerevisiae.

1986

When S. cerevisiae growing in the presence of glucose (repressive condition) was shifted to higher temperatures, invertase was secreted. This secretion required protein synthesis, but was independent of RNA formation (Mormeneo & Sentandreu 1982). In addition accumulation of invertasespecific messenger RNA occurred in the absence of protein synthesis but was expressed only after synthesis of protein. Invertase mRNA was continuously synthesized under repressive conditions and the levels of this mRNA were regulated by the presence of glucose. The hexose regulated the concentration of this mRNA at the level of transcription and/or by sensitization of this messenger RNA. The expression of the in…

Candida albicans UBI3 and UBI4 promoter regions confer differential regulation of invertase production to Saccharomyces cerevisiae cells in response …

2002

Candida albicans ubiquitin genes UBI3 and UBI4 encode a ubiquitin-hybrid protein involved in ribosome biogenesis and polyubiquitin, respectively. In this work we show that UBI3 and UBI4 promoter regions confer differentialexpr ession consistent with the function of their encoded gene products. Hybrid genes were constructed containing the SUC2 coding region under the controlof UBI3 or UBI4 promoters in the yeast vector pLC7. Invertase production in Saccharomyces cerevisiae transformants was differentially regulated: the UBI4 promoter was induced by stress conditions (thermalupshift and/or starvation) whereas the UBI3 promoter conferred constitutive invertase production in growing yeast cells…

Polypeptide composition of invertase-containing vesicles of Saccharomyces cerevisiae

1990

Vesicles containing invertase activity were obtained from protoplast homogenates of Saccharomyces cerevisiae by differential centrifugation followed by gel chromatography. These vesicles were similar in size and shape to yeast coated vesicles, and appear to have a complex polypeptide composition. Most of these polypeptides were seemingly bound to the surface of the vesicular structures, being released by treatment with alkali. A protein with an electrophoretic mobility similar to that of yeast clathrin (molecular mass of 185 kDa) co-purified with vesicles containing invertase activity, and exhibited cross-reactivity with anti-mammalian (pig) clathrin antibodies.

The Yeast External Invertase as a Reporter to Study Regulation ofCandida Albicans Promoter Sequences inSaccharomyces Cerevisiae

2008

Starvation and temperature upshift cause an increase in the enzymatically active cell wall-associated glyceraldehyde-3-phosphate dehydrogenase protei…

2003

The cell wall-associated glyceraldehyde-3-phosphate dehydrogenase (cwGAPDH) activity in Saccharomyces cerevisiae increases (two- to 10-fold, depending on the strain) in response to starvation and temperature upshift. Assays using transformants carrying pTDH, a yeast centromer derivative plasmid containing the Candida albicans TDH3 gene (encoding GAPDH) fused in frame with the yeast SUC2-coding region for internal invertase, showed that starvation and/or temperature upshift result in a similar increase in both cwGAPDH and cell wall-associated invertase activities. In addition, this incorporation of GAPDH protein into the cell wall in response to stress does not require (i) de novo protein sy…