Proteome-Level Analysis of Metabolism- and Stress-Related Proteins during Seed Dormancy and Germination in <i>Gnetum parvifolium</i>

Gnetum parvifolium is a rich source of materials for traditional medicines, food, and oil, but little is known about the mechanism underlying its seed dormancy and germination. In this study, we analyzed the proteome-level changes in its seeds during germination using isobaric tags for relative and absolute quantitation. In total, 1,040 differentially expressed proteins were identified, and cluster analysis revealed the distinct time points during which signal transduction and oxidation–reduction activity changed. Gene Ontology analysis showed that “carbohydrate metabolic process” and “response to oxidative stress” were the main enriched terms. Proteins associated with starch degradation and antioxidant enzymes were important for dormancy-release, while proteins associated with energy metabolism and protein synthesis were up-regulated during germination. Moreover, protein-interaction networks were mainly associated with heat-shock proteins. Furthermore, in accord with changes in the energy metabolism- and antioxidant-related proteins, indole-3-acetic acid, Peroxidase, and soluble sugar content increased, and the starch content decreased in almost all six stages of dormancy and germination analyzed (S1–S6). The activity of superoxide dismutase, abscisic acid, and malondialdehyde content increased in the dormancy stages (S1–S3) and then decreased in the germination stages (S4–S6). Our results provide new insights into G. parvifolium seed dormancy and germination at the proteome and physiological levels, with implications for improving seed propagation

Table_1_Significance of Photosynthetic Characters in the Evolution of Asian Gnetum (Gnetales).XLSX

Gnetum is a genus in the Gnetales that has a unique but ambiguous placement within seed plant phylogeny. Previous studies have shown that Gnetum has lower values of photosynthetic characters than those of other seed plants, but few Gnetum species have been studied, and those that have been studied are restricted to narrow taxonomic and geographic ranges. In addition, the mechanism underlying the lower values of photosynthetic characters in Gnetum remains poorly understood. Here, we investigated the photosynthetic characters of a Chinese lianoid species, i.e., Gnetum parvifolium, and co-occurring woody angiosperms growing in the wild, as well as seedlings of five Chinese Gnetum species cultivated in a greenhouse. The five Gnetum species had considerably lower values for photosynthesis parameters (net photosynthetic rate, transpiration rate, intercellular CO2 concentration, and stomatal conductance) than those of other seed plant representatives. Interrelated analyses revealed that the low photosynthetic capacity may be an intrinsic property of Gnetum, and may be associated with its evolutionary history. Comparison of the chloroplast genomes (cpDNAs) of Gnetum with those of other seed plant representatives revealed that 17 coding genes are absent from the cpDNAs of all species of Gnetum. This lack of multiple functional genes from the cpDNAs probably leads to the low photosynthetic rates of Gnetum. Our results provide a new perspective on the evolutionary history of the Gnetales, and on the ecophysiological and genomic attributes of tropical biomes in general. These results could also be useful for the breeding and cultivation of Gnetum.</p

Modeling SME credit ratings using non-homogenous backward semi-Markovian approach

A Dissertation submitted in partial fulfillment of the requirements for the Master of Science in Mathematical Finance (MSc.MF) at Strathmore UniversityConsidering the growth in SME lending in Kenya and the obvious risks it posses to the banking sector, we establish a credit risk model that is responsive to the jumps in the economy. This is based on simulation of implied values of credit worthiness over a period of 12 months for 1000 SMEs, in which case we establish a case for the discrete time non-homogeneous semi-Markov approach as a proxy for internal rating model for a portfolio of SME loans. While viewing credit risk as a reliability issue, the model provides a credit indicator which gives a prospective measure of credit risk for an SME portfolio. Banks seeking to comply with the new IFRS9 guidelines can espouse this model to adequately measure impairment of financial instruments

It's Christmas Carol (2006)

1. Poster, 2. Photo, 3. Photo, 4. Photo, 5. Photo, 6. Photo, 7. Photo, 8. Photo, 9. Photo, 10. Photo, 11. Photo, 12. Photo, 13. Photo, 14. Photo, 15. Program, 16. Press Release English, 17. Press Release FrenchArchival file for the Glendon College production of It's Christmas Carol, written and directed by Nicole Toogood. The play was performed November 30th - December 9th, 2006

Ranking of candidate reference genes in order of their expression stability as calculated by NormFinder.

<p>Note: Expression stability and ranking of 10 reference genes as calculated by NormFinder in all samples (A), different ages (B), different tissue types (C), cold-treated (D), heat-treated (E), NaCl-treated (F), PEG-treated (G), ABA-treated (H). Lower average expression stability (M value) indicates more stable expression.</p

Descriptions of candidate genes from <i>Platycladus orientalis</i> for qRT-PCR.

<p>Note: All reference gene sequences from transcriptome data of <i>Platycladus orientalis</i> were searched with BLAST using sequences of <i>Arabidopsis thaliana</i> in GenBank. Sequences of candidate housekeeping genes and NAC domain protein gene are provided in the Supporting Information.</p

Expression profiles of <i>NAC</i> in different-aged tissues and in response to stresses in <i>Platycladus orientalis</i> (as determined by qRT-PCR with UBC and aTUB in combination as reference genes).

<p>Expression profiles of <i>NAC</i> in different-aged tissues and in response to stresses in <i>Platycladus orientalis</i> (as determined by qRT-PCR with UBC and aTUB in combination as reference genes).</p

Figure 1

<p> <b>Expression levels of candidate reference genes in different plant samples.</b></p

Gene expression stability and ranking of 10 reference genes as calculated by geNorm.

<p>Gene expression stability and ranking of 10 reference genes as calculated by geNorm.</p

Determination of the optimal number of reference genes for normalization by pairwise variation (V) using geNorm.

<p>Determination of the optimal number of reference genes for normalization by pairwise variation (V) using geNorm.</p