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David W. Still and Kent J. Bradford

Lettuce seeds were germinated at 20 C in the dark in water and sampled at various intervals during the first 18h of germination to determine quantitative and qualitative differences in proteins. The soluble protein fraction was partitioned into albumins and globulins by dialysis and the proteins of the globulin fraction were visualized by SDS-PAGE. Heat stable proteins were obtained by boiling the proteins, cooling on ice, and resuspending in buffer.

The soluble protein content remained constant during the first 8h of germination. Thereafter protein content decreased and was 6% of the amount present in unimbibed seed in 21 day old seedlings. The ratio of heat stable to heat unstable proteins decreased during the germination process. No differences in banding patterns were observed when the soluble protein fraction were run on SDS-PAGE. However, on gels run with the globulin fraction a 57 kD protein appeared 4 and 8 h after imbibition and had disappeared by 12 h after imbibition. The role of proteins and heat-stable proteins during germination and prevention of dessication during early seedling growth is discussed.

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Hyesoon Kim and Yeh-Jin Ahn

stress. All living organisms, including plants, respond to heat stress (10 to 15 °C above their optimal growth temperatures) by producing a set of proteins called heat shock proteins (HSPs; Wahid et al., 2007 ). In eukaryotic organisms, HSPs are

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Da-Peng Zhang, Zi-Lian Zhang, Jia Chen, and Jiang Lu

By using the micro-volume radio-ligand binding essay, the changes in the kinetic characteristics of the abscisic acid (ABA)-binding protein(s) of the Kyhoh grapevine (Vitis vinifera × V. labrusca) fruit during the different stages of fruit development have been studied. The changes in the berry volume growth, concentration of sugar, organic acids, and ABA in fruit mesocarp have been surveyed, especially for studies of ABA-binding protein. The dissociation constant (Kd) and ABA binding maximum (Bmax) were determined by the Scatchard plots for ABA binding in microsomes of the fruit. They are Kd = 17.5, 50.0, 6.3, 13.3 nmol·L–1; Bmax = 98.6, 523.0, 41.6, 85.4 μmol·mg–1 protein, respectively, for the fruit developmental phase I, II, veraison, and phase III. The Scatchard plots showed a rectilinear function for all of the developmental phases including veraison, which suggests the sole ABA-binding site of high affinity for ABA in the fruit microsomes, but this site could either be only one kind of the same protein or consist of more kinds of different proteins for different developmental stages. The binding affinity of ABA-binding protein(s) for ABA was shown to be higher at veraison time than during other developmental phases; this binding affinity increased nearly by 10 times from phase II to veraison, while the concentration (Bmax) of the ABA-binding protein(s) decreased to the minimum at veraison. The very low concentration of ABA at veraison may be able to trigger the onset of fruit ripening due to the increase of the binding affinity of ABA-binding protein(s) for ABA at this time. The possible functions of the ABA-binding protein(s) for fruit development during the different developmental stages were discussed, and it is suggested that the protein(s) detected could be the putative ABA receptor(s) or transporter(s) for the action of this plant hormone in grapevine.

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Xiaojuan Zong, Jiawei Wang, Li Xu, Hairong Wei, Xin Chen, Dongzi Zhu, Yue Tan, and Qingzhong Liu

; Zhang et al., 2006 ; Zwerger and Hirt, 2001 ). MAPKs are dual-specificity protein kinases that are activated by mitogen-activated protein kinase kinases through double phosphorylation of the Thr-x-Tyr (T-x-Y) motif in the activation loop (T-loop). Four

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Mehrassa Khademi, David S. Koranski, and Joan Peterson

Seeds of Primula acaulis (L.) J. Hill `Dukaat Helderrose' were imbibed for 48 h at 18C, and Maltrin 600 solution was used to separate them into density classes of 1.10, 1.12, 1.14, 1.16, and 1.18 g·cm-3. Seeds were rinsed, air-dried for 48 h at 22C, and germinated at 18C; 80% were separated into density classes between 1.16 and 1.18 g·cm-3. Percentages of germination and high-vigor seedlings were significantly greater for seeds with densities >1.14 g·cm-3. Soluble protein concentration increased with density, whereas insoluble protein concentration was unchanged. Distinct protein groups with estimated molecular weights of ≈50, 33, and 25 kDa were present in the protein profile of nonseparated imbibed seed. These proteins were most abundant at densities ≥1.16 g·cm-3. The 25-kDa protein was present only in higher density seed. Presence of an additional 14-kDa protein was noted in the insoluble protein profile. Certain proteins in the soluble protein fraction maybe used to test for seed vigor.

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J.M. Sherman, K.S. Reddy, S.E. Newman, and J.A. Spencer

Most modern roses are highly susceptible to the disease blackspot caused by the fungus Diplocarpon rosae. This contrasts to species roses that are resistant to the disease. To gain information on the biochemical factors in this resistance mechanism, we are studying the involvement of proteins. Soluble proteins of modern roses and species roses were extracted and analyzed by SDS-PAGE. When healthy leaves were examined, there were no distinct differences in the protein patterns, indicating that there are no constitutive proteins involved in the disease resistance mechanism. There were no differences between healthy and infected leaves of resistant genotypes. When detached leaves of some susceptible types were infected with the fungus new proteins seemed to appear in the healthy region surrounding the blackspot lesion. These proteins may be involved in resisting the spread of the pathogen.

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M.P. Bañados, M.S. Santiago, and C. Eterovic

The main form of nitrogen reserves during overwintering are amino acids and proteins. Specific proteins called bark storage proteins (BSP) have been characterized in many tree species. To identify BSPs in `O'Henry' peach, `Angeleno' plum, and `Early Burlat' cherry trees, samples of bark were collected from January through December 1993 from trees growing under field conditions in Santiago, Chile. SDS-PAGE analyses were used to characterize the seasonal variation on the protein pattern on the bark of those Prunus species. A 60 kDa BSP was identified in the bark of all three species, which corresponds to the main protein present in the bark during the winter. This protein may play an important role as a nitrogen reserve in these fruit trees.

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Hanseul Park and Yeh-Jin Ahn

Escherichia coli is an important industrial microorganism that is most widely used for recombinant protein production (reviewed in Jana and Deb, 2005 ). However, during mass production, bacterial cell growth can be hindered by a number of factors

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Harbans L. Bhardwaj and Anwar A. Hamama

Tepary bean (Phaseolus acutifolius A. Gray), a native of southwestern U.S., is a promising plant for crop diversification and for production in short rotations with wheat. However, protein and mineral concentrations in tepary bean seed produced outside the southwestern U.S. are largely unknown. We evaluated concentrations of protein and various minerals in seed produced by eight tepary bean genotypes planted at three different dates each during 1997 and 1998 at Ettrick, Virginia. Significant year × planting date and year × genotype interactions existed for protein and other traits. Protein and zinc concentrations increased and calcium concentrations decreased with later plantings during both years. Mid-June planting had 14% higher protein concentration (24.5%) than late-May planting (21.4%) and mid-July planting had 6% higher protein concentration (25.9%) than mid-June planting. Color of seedcoat was not associated with concentrations of protein or minerals. The average concentrations of boron, calcium, copper, iron, potassium, magnesium, manganese, phosphorus, sulfur, and zinc (mg/100g) were: 1, 184, 1, 11, 1531, 192, 3, 451, 311, 4, respectively. Tepary bean seeds contained 24% protein as compared to reported average values of 22.3% in navy, 22.5% in red kidney, and 20.9% in pinto bean. The average iron concentration (mg/100g) in tepary bean seed (10.7) was higher than that in navy (6.4), red kidney (6.7), and pinto (5.9) bean. Based on protein and mineral concentrations tepary bean seed compared well with seeds of navy, red kidney, or pinto bean.

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Huiling Wang, Wei Wang, Weidong Huang, and Haiying Xu

, little was known about the regulation at the protein level. In addition, the relationships between SA and the downstream enzymes of flavonoid biosynthesis such as Vv DFR and Vv ANS have not yet been reported in grapevine. Paclobutrazol can significantly