Photosynthetic activity of variegated leaves of Coleus × hybridus hort. cultivars characterised by chlorophyll fluorescence techniques

Different pigments often occur together and affect photosynthetic characteristics of the respective leaf portions. In this study, photosynthetic activity in variegated leaves of five cultivars of the ornamental and medicinal plant, Coleus × hybridus hort., was estimated by image analysis and point data measurements of major chlorophyll (Chl) fluorescence parameters and related to the amount of photosynthetic pigments measured with a Chl meter or spectrophotometrically in leaf extracts. Significant differences in Chl and carotenoid (Car) contents were noticed among differentially pigmented sectors of a leaf and among the cultivars. Although the higher Chl concentration was noticed in purple parts compared to green parts of the leaves, the values of minimal and maximal fluorescence yield at the dark- and light-adapted state (F₀, F_m, F₀', F_m', respectively) were a little lower than those in the green sectors, indicating photoprotective effects provided by anthocyanins and Car, more abundant in the red parts. The lowest Chl and Car content was detected in creamy-yellow and pink sectors and this contributed to low F₀, F_m, and F_m', maximal quantum yield of PSII photochemistry, and nonphotochemical and photochemical quenching but high PSII maximum efficiency and effective quantum yield of PSII photochemistry. Both methods of Chl fluorescence analysis revealed heterogeneity in capture, transfer, and dissipation of excitation energy but Chl fluorescence imaging was more suitable in examining very narrow pigmented leaf areas.     

Variability of globulin composition in cultivars and individually tested seeds of yellow lupin (Lupinus luteus L.)

A study on globulins, major storage proteins in yellow lupin seeds, called conglutins, was conducted using SDS polyacrylamide gel electrophoresis. In this paper, an extensive and not yet published list of yellow lupin conglutins is presented. The patterns of subunits of major conglutins in seeds of three yellow lupin cultivars were similar to each other, varying only in the level of some polypeptides. Investigations of seeds of cultivar Parys showed considerable quantitative differences in major subunits. Some minor subunits occurred only in some seeds and were absent in the others. Great differences were shown between single individuals in the amount of subunits of conglutin which is of the most nutritional value due to high content of methionine.     

Comparative study of storage compound breakdown in germinating seeds of three lupine species

Storage lipid and protein breakdown in germinating seeds of yellow (Lupinus luteus L.), white (L. albus L.), and Andean lupine (L. mutabilis Sweet) and regulatory function of sucrose were investigated. Less oil bodies were detected in organs of yellow lupine seeds, whereas the highest content of oil bodies was noticed in the Andean lupine seeds. Mature, air-dried yellow, white and Andean lupine seeds do not contain starch. Starch grains appear the earliest in white lupine seeds during imbibition. Sucrose deficiency in tissues enhances breakdown of storage lipid, protein and temporary starch in cotyledons. In sucrose starved embryo axes of all investigated lupine species, an increased level of vacuolization was noted. Interconnections between catabolism of storage protein and storage lipid in germinating lupine seeds were identified by applying ¹⁴C-acetate. To assess the importance of key processes in storage lipid breakdown NaF (inhibitor of glycolysis and gluconeogenesis), KCN, NaN₃ and SHAM (inhibitors of mitochondrial electron transport chain) and MSO (inhibitor of glutamine synthetase) were used. Radioactivity coming from ¹⁴C-acetate was released as ¹⁴CO₂ but mostly was incorporated into ethanol-soluble fraction of embryo axes and cotyledons. Respiratory inhibitors caused a significant decrease in ¹⁴CO₂ and ethanol fractions in all three lupine species studied. MSO stimulated release of ¹⁴CO₂ and radioactivity of ethanol fractions in yellow lupine organs fed with sucrose, but in Andean lupine MSO enhanced the production of ¹⁴CO₂ and radioactivity of ethanol fractions both in organs fed and not fed with sucrose. Different strategies of storage compound breakdown are proposed, depending on relative proportion in storage protein and lipid content in lupine seeds.     

Expression of RAGE and HMGB1 in Thymic Epithelial Tumors,Thymic Hyperplasia and Regular Thymic Morphology

Recently, a role of the receptor for advanced glycation endproducts (RAGE) in myasthenia gravis was described. RAGE and its ligand high mobility group box 1 (HMGB1) play key roles in autoimmunity and cancer. To test whether these molecules are involved in patients with thymic abnormalities we applied immunohistochemical analysis in 33 cases of thymic epithelial tumors, comprising 27 thymomas and 6 thymic carcinomas, and 21 nonneoplastic thymuses. Both molecules were detected in neoplastic epithelial cells: RAGE staining was most intense in WHO type B2 thymomas and thymic carcinomas (p<0.001). HMGB1 nuclear staining was strongest in A and AB, and gradually less in B1 = B2>B3>thymic carcinoma (p<0.001). Conversely, HMGB1 cytoplasmic staining intensities were as follows: A and AB (none), B1 (strong), B2 (moderate), B3 and thymic carcinoma (weak); (p<0.001). Fetal thymic tissue showed a distinct expression of RAGE and HMGB1 in subcapsular cortical epithelial cells which was found in 50% of myasthenic patients. Furthermore RAGE and HMGB1 were expressed in thymocytes, macrophages, Hassall''s corpuscles, thymic medulla, and germinal center cells in myasthenic patients. Immunohistochemistry results were complemented by systemic measurements (immunosorbent assay): serum levels of soluble RAGE were significantly reduced in patients with epithelial tumors (p = 0.008); and in invasive tumors (p = 0.008). Whereas RAGE was equally reduced in thymic hyperplasia and epithelial tumors (p = 0.003), HMGB1 was only elevated in malignancies (p = 0.036). Results were most pronounced in thymic carcinomas. Thus, RAGE and HMGB1 are involved in the (patho-)physiology of thymus, as evidenced by differentiated thymic and systemic expression patterns that may act as diagnostic or therapeutic targets in autoimmune disease and cancer.     

Structure-function relationships of retinoids in their effects on retinol-binding protein metabolism in cultured H4II EC3 liver cells

Studies were conducted to explore the structural features of retinoids that may be required to stimulate the secretion or production of retinol-binding protein (RBP) by H4II EC3 rat hepatoma cells in culture. Sixteen retinoids, that differed from all-trans-retinol in the cyclohexene ring, the polyene side chain, and/or the functional end group, were each incubated with H4II EC3 cells, and RBP secretion and accumulation were determined by radioimmunoassay. A number of retinoids, in addition to retinol, effectively stimulated RBP secretion. The results suggest that an intact cyclohexene ring may be necessary for the stimulation of RBP secretion. In contrast the system did not exhibit much specificity with regard to either the structure of the side chain or the nature of the end group. No relationship was found between the ability of a retinoid to stimulate RBP secretion and production and its biological activity. The biologically active retinoid, 13-cis-retinoic acid, was inactive in the present system, whereas the biologically inactive perhydromonoeneretinol was moderately effective in stimulating both RBP secretion and accumulation. In contrast, there appeared to be some relationship between the ability of different retinoids to stimulate RBP secretion and their ability to bind to RBP. In general, retinoids that had previously been shown to bind to RBP produced a greater stimulation of RBP secretion than those that did not bind to RBP. The secretion of RBP obtained with a given retinoid was not well correlated with the net accumulation of RBP. For example, retinoyl amide did not stimulate RBP secretion but was moderately effective in stimulating RBP accumulation. Thus, the secretion of RBP does not appear to be necessary for the stimulation of the net accumulation of RBP.     

Herpes Simplex Virus Types 1 and 2 Completely Help Adenovirus-Associated Virus Replication

In addition to adenoviruses, which are capable of completely helping adenovirus-associated virus (AAV) multiplication, only herpesviruses are known to provide any AAV helper activity, but this activity has been thought to be partial (i.e., AAV DNA, RNA, and protein syntheses are induced, but infectious particles are not assembled). In this study, however, we show that herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are in fact complete AAV helpers and that AAV type 2 (AAV2) infectivity yields can approach those obtained when coinfections are carried out with a helper adenovirus. AAV helper activity was demonstrated in KB cells with two HSV-1 strains (11124 and 17MP) and an HSV-2 strain (HG52). Each herpesvirus supported AAV2 multiplication with comparable efficiency. AAV2 multiplication was similarly efficient in HSV-1 coinfections of HeLa cells, whereas lower yields were obtained in HEp-2 and primary human embryonic kidney cells. HSV-1 also supported AAV1 multiplication in HeLa cells but, at corresponding multiplicities of infection, AAV1 grew less efficiently than AAV2. Comparisons of the time courses of AAV2 DNA, RNA, and protein syntheses after coinfection with either adenovirus type 5 or HSV-1 revealed that, in each case, the onset of synthesis and attainment of maximal synthesis rate occurred earlier in coinfections with HSV-1. These findings demonstrate the linkage of AAV macromolecular synthesis to an event(s) in the helper virus cycle. Aside from this temporal association, helper-related differences in AAV macromolecular synthesis were not apparent.