Number of results to display per page
Search Results
7282. Effect of tick salivary gland extract on the cytokine production by mouse epidermal cells
- Creator:
- Pechová, Jitka, Kopecký, Jan, and Salát, Jiří
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Ixodes ricinus, salivary gland extract, Borrelia afzelii, mouse epidermal cells, and cytokines
- Language:
- English
- Description:
- Previous studies have demonstrated that both tick saliva and Borrelia burgdorferi sensu lato antigens modulate the cytokine response of the host. In this paper, the effect of salivary gland extract (SGE) from Ixodes ricinus (L., 1758) ticks on cytokine production by primary cultures of mouse epidermal cells stimulated with Borrelia afzelii Canica, Nato, du Merle, Mazie, Baranton et Postic, 1993 spirochetes was analysed. Epidermal cells were derived from C3H/HeN mice, susceptible to Lyme disease, and BALB/c mice, which are resistant. In cultures from C3H/HeN mice, SGE down regulated production of tumour necrosis factor alpha (TNF-α) and up regulated Th2 cytokine, interleukin 4 (IL-4). Cultures from BALB/c mice produced higher basal levels of monitored cytokines, but their production was affected by SGE a different way. While Th2 cytokines IL-6 and IL-10 were down regulated, the effect on TNF-α and IL-4 was ambiguous. These results indicate that the effect of tick saliva on the epidermal cells of Lyme disease-susceptible C3H/HeN mice mirrors its effect on other cells of the immune system.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7283. Effect of topdressing on individual leaf photosynthesis at different position in direct-sown rice with non-woven fabric mulch system
- Creator:
- Hossain, S. T., Sugimoto, H., and Yamashita, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- leaf nitrogen, organic farming, and Oryza sativa
- Language:
- Multiple languages
- Description:
- Direct sowing with non-woven fabric mulch is the new organic rice cultivation system. We studied the effect of topdressing on individual leaf photosynthesis at different position and grain yield in rice plants cultivated by this system. Leaf photosynthetic rate at the different leaf position per plant (PN-LP) of the third and fourth to lower leaves was higher when the topdressing amount was increased. Without topdressing or in no-fertilizers plots, the PN-LP values of lower leaves were very low. The leaf photosynthetic rate per unit leaf area (PN-LA) decreased gradually as the leaf position became lower. Again, the PN-LA values of the top-dressed plots at the lower leaves were higher than that of plots without topdressing or without fertilizers. The lower leaves maintained a higher PN because of a higher rate of nitrogen accumulation due to topdressing. The higher rate of photosynthesis in these leaves resulted in better root activity, which contributed to a better ripening percentage and ultimately higher rice grain yield. and S. T. Hossain, H. Sugimoto, J. Yamashita.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7284. Effect of ultraviolet-B radiation on growth, photosynthetic pigments, and cell biology of Kappaphycus alvarezii (Rhodophyta, Gigartinales) macroalgae brown strain
- Creator:
- Schmidt, É. C., Nunes, B. G., Maraschin, M., and Bouzon, Z. L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, brown strain of Kappaphycus alvarezii, chloroplast, growth rates, photosynthetic pigments, ultrastructure, and ultraviolet-B radiation
- Language:
- Multiple languages
- Description:
- Kappaphycus alvarezii is a seaweed of great economic importance for the extraction of kappa carrageenan from its cell walls. The most common strains are dark red, brown, yellow, and different gradations of green. It is known that ultraviolet radiation (UVR) affects macroalgae in many important ways, including reduced growth rate, reduction of primary productivity, and changes in cell biology and ultrastructure. Therefore, we examined the brown strain of K. alvarezii exposed to ultraviolet-B radiaton (UVBR) for 3 h per day during 28 days of cultivation. The control plants showed growth rates of 7.27% d-1, while plants exposed to UVBR grew only 4.0% d-1. Significant differences in growth rates and in phycobiliproteins between control and exposed plants were also found. Compared with control plants, phycobiliprotein contents were observed to decrease after UV-B exposure. Furthermore, the chlorophyll a (Chl a) contents decreased and showed significant differences. UVBR also caused changes in the ultrastructure of cortical and subcortical cells, which included increased thickness of the cell wall and number of plastoglobuli, reduced intracellular spaces, changes in the cell contour, and destruction of chloroplast internal organization. Reaction with Toluidine Blue showed an increase in the thickness of the cell wall, and Periodic Acid-Schiff stain showed a decrease in the number of starch grains. By the significant changes in growth rates, photosynthetic contents and ultrastructual changes observed, it is clear that UVBR negatively affects intertidal macroalgae and, by extension, their economic viability. and É. C. Schmidt ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7285. Effect of UV radiation on pigments of the Antarctic macroalga Leptosomia simplex L.
- Creator:
- Döhler, G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- α- and β-carotenes, chlorophyll, chlorophyllide, lutein, UV-A and UV-B radiation, and zeaxanthin
- Language:
- Multiple languages
- Description:
- Impact of UV-A and UV-B radiation on pattern of pigments of the Antarctic macroalga Leptosomia simplex L. was studied during the Polarstern cruise (ANT XII/2) 1994/95 under controlled laboratory conditions. An 8 h exposure to UV-A of 17.6 W m-2 led usually to an increase of carotenoid contents, but to a decrease in contents of chlorophyllide (Chlide) a and chlorophyll (Chl) a. UV-B irradiation (300-320 nm) caused a decrease in contents of Chlide a, lutein, and zeaxanthin, but an increase in contents of Chl a and carotenes. Enhancement of carotenoid contents was attributed to a protection of the photosynthetic apparatus. UV effects on the 15N-ammonium uptake were correlated with the changes in pigment contents.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7286. Effect of vermicompost fertilizer on photosynthetic characteristics of chickpea (Cicer arietinum L.) under drought stress
- Creator:
- Hosseinzadeh, S. R., Amiri, H., and Ismaili, A.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorophyll a fluorescence, gas exchange, organic fertilizer, stomatal limitation, water stress, 2, and 581
- Language:
- Multiple languages
- Description:
- Water availability is an important factor for plant growth in arid environments. In recent decades, vermicompost (VC) fertilizer has been used in agriculture as a safe and effective fertilizer with high water-holding capacity. The aim of the present study was to characterize effects of VC fertilizer on photosynthetic activity of chickpea (Cicer arietinum L. cv. Karaj) under drought conditions at three different growth stages. Tests were carried out with four volumetric ratios of VC to soil, i.e., 0:100, 10:90, 20:80, and 30:70, and three levels of drought stress, i.e., no stress (NS), moderate drought (MS), and severe drought (SS) (100, 75, and 25% of field capacity, respectively). Evaluations were performed at the seedling, flowering, and podding stage. We found that the VC treatment under NS conditions significantly increased total chlorophyll content [Chl (a+b)], intercellular CO2 concentration (C i), net photosynthetic rate (P N), transpiration rate (E), and maximal quantum yield of PSII photochemistry (Fv/Fm) at all three stages. The VC addition of 10 and 20% significantly enhanced the Chl content and Fv/Fm under MS and Fv/Fm, C i, and P N under SS at the flowering stage. In conclusion, our results proved a positive effect of the VC fertilizer on photosynthesis of chickpea under NS conditions, but it was not found under MS and SS., S. R. Hosseinzadeh, H. Amiri, A. Ismaili., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7287. Effect of water deficit on photosynthetic and other physiological responses in grapevine (Vitis vinifera L. cv. Riesling) plants
- Creator:
- Bertamini, M., Zulini, L., Muthuchelian, K., and Nedunchezhian, N.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- amino acids, chlorophyll, net photosynthetic rate, nitrate reductase, proline, protease, relative water content, and ribulose-1,5-biphosphate carboxylase
- Language:
- Multiple languages
- Description:
- The grapevine (Vitis vinifera L. cv. Riesling) plants subjected to water deficit were studied for changes in relative water content (RWC), leaf dry mass, contents of chlorophyll (Chl), total leaf proteins, free amino acids, and proline, and activities of ribulose-1,5-bisphosphate carboxylase (RuBPC), nitrate reductase (NR), and protease. In water-stressed plants RWC, leaf dry matter, Chl content, net photosynthetic rate (PN), and RuBPC and NR activities were significantly decreased. The total leaf protein content also declined with increase in the accumulation of free amino acids. Concurrently, the protease activity in the tissues was also increased. A significant two-fold increase in proline content was recorded. and M. Bertaminni ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7288. Effect of water stress on photosynthesis and growth in two teak phenotypes
- Creator:
- Rajendrudu, G., Naidu, C. V., and Mallikarjuna, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- leaf growth, net photosynthetic rate, stomatal conductance, Tectona grandis, and transpiration rate
- Language:
- Multiple languages
- Description:
- Two teak (Tectona grandis L.f.) phenotypes differing in their leaf length/breadth ratios were subjected to water stress by withholding water supply for three weeks. Growth rates of whole plants, developing leaves (1st and 2nd from shoot apices), and 2nd and 3rd internodes were higher in broad leaved (BL) phenotype than in narrow leaved (NL) phenotype before and after imposing water stress treatment. However, the effect of water stress on these parameters was higher in the BL phenotype than in the NL one. Diurnal course of net photosynthetic rate (PN) of 3rd or 4th leaves from shoot apices measured under well-watered conditions was higher for the NL than BL phenotype. PN, stomatal conductance (gs), and transpiration rate (E) in both phenotypes were negatively affected by water stress and their decline under water stress was significantly higher in the BL than NL plants. and G. Rajendrudu, C. V. Naidu, K. Mallikarjuna.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7289. Effect of water stress on photosynthesis in two mulberry genotypes with different drought tolerance
- Creator:
- Ramanjulu, S., Sreenivasulu, N., and Sudhakar, C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Ci/gs ratio, cultivar differences, intercellular CO2 concentration, Morus alba, net photosynthetic rate, photosystem 2, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Three-month-old mulberry (Morus alba L.) cultivars (drought tolerant S13 and drought sensitive S54) were subjected to water stress for 15 d. Water stress decreased the leaf water potential, net photosynthetic rate (PN), and stomatal conductance (gs) in both the cultivars. However, the magnitude of decline was comparatively greater in the sensitive cultivar (S54). Intercellular CO2 concentration (Ci) was unaltered during mild stress, but significantly increased at severe stress in both cultivars. The photosystem 2 activity significantly declined only at a severe stress in both cultivars. The Ci/gs ratio representing the mesophyll efficiency was greater in the tolerant cultivar S13. Involvement of stomatal and/or non-stomatal components in declining PN depended on the severity and duration of stress. However, the degree of non-stomatal limitations was relatively less in the drought tolerant cultivar. and S. Ramanjulu, N. Sreenivasulu, C. Sudhakar.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7290. Effect of weedy rice at different densities on photosynthetic characteristics and yield of cultivated rice
- Creator:
- Xu, X. M., Li, G., Su, Y., and Wang, X. L.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorofylová fluorescence, hustota, výměna plynu, rýže setá, sklizeň, chlorophyll fluorescence, density, gas exchange, Oryza sativa, weedy rice, yield, 2, and 581
- Language:
- Multiple languages
- Description:
- In order to evaluate effect of weedy rice on the photosynthesis and grain filling of cultivated rice, cultivated rice ‘Nanjing 44‘ was planted in the field under different densities of weedy rice ‘JS-Y1‘ for two years. The results showed that net photosynthetic rate (PN), net assimilation rate, grain filling rate, and the grain yield of cultivated rice all decreased with increasing weedy rice density. Furthermore, yield component analysis revealed that increasing weedy rice density had the most significant effect on the percentage of filled grains and the number of rice panicles. The correlation analyses indicated that the yield of cultivated rice was highly correlated with the net photosynthetic rate and the net assimilation rate. Our results illustrated that high density of weedy rice might cause yield losses in cultivated rice by inhibition of photosynthesis and grain filling., X. M. Xu, G. Li, Y. Su, X. L. Wang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public