Search

Start Over Format počítač Rights http://creativecommons.org/licenses/by-nc-sa/4.0/

393. Latent toxoplasmosis and vitamin D concentration in humans: three observational studies

Creator:
Kaňková, Šárka, Bičíková, Marie, Máčová, Ludmila, Hlaváčová, Jana, Sýkorová, Kateřina, Jandová, Dobroslava, and Flegr, Jaroslav
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
Toxoplasma gondii, calcidiol, depression, mental disorders, and schizophrenia
Language:
English
Description:
Numerous recent studies show that vitamin D deficiency potentiates various chronic physical and psychiatric disorders and diseases. It has been shown that a similar range of disorders is also associated with latent infection with Toxoplasma gondii (Nicolle et Manceaux, 1908). For instance, among cancer, diabetes and schizophrenia patients, we find a higher prevalence of both toxoplasmosis and vitamin D deficiency. Theoretically, therefore, vitamin D deficiency could be the missing link between toxoplasmosis and these disorders. We tested this hypothesis by searching for decreased vitamin D levels in the serum of subjects infected with T. gondii (furthermore called Toxoplasma-infected subjects) in two cross-sectional and one case-control study. Results of the first cross-sectional study (N = 72) suggest that Toxoplasma-infected neurasthenic patients have non-significantly lower levels of calcidiol than Toxoplasma-free patients (study A: P = 0.26 in women, P = 0.68 in men). However, two other studies (study B: N = 400; study C: N = 191) showed a non-significantly higher concentration of vitamin D in Toxoplasma-infected subjects than in Toxoplasma-free subjects both in men (study B: P = 0.70, study C: P = 0.55) and in women (study B: P = 0.64, study C: P = 0.12). Taken together, our preliminary results thus do not support the hypothesis that toxoplasmosis could be associated with vitamin D decrease.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

394. Leaf structure and photosynthesis in Populus alba under naturally fluctuating environments

Creator:
Lin, X. Y., Wang, X. X., Zeng, Q. Y., and Yang, Q.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
fluctuating conditions, photoinhibition, photosynthesis, plasticity, and Populus alba
Language:
Multiple languages
Description:
The ability to modulate photosynthesis is essential for plants to adapt to fluctuating growing conditions. Populus species show high tolerance to various and highly variable environments. To understand their response strategies against fluctuating environments, this study investigated the morphological and physiological differences of white poplar (Populus alba) leaves when grown in a phytotron, glasshouse, and field. Our results show that the palisade cells were elongated in the field, which would enhance intercellular CO2 exchange. Photosynthetic capacity was the highest in the field leaves, as shown by higher electron transport rates (1.8 to 6.5 times) and carbon assimilation rates (2.7 to 4.2 times). The decrease of PSI acceptor-side limitation and increase of PSI donor-side limitation suggests changes in PSI redox status may contribute to photoprotection. This plasticity of white poplar allows adjusting its structure and photosynthesis under fluctuating conditions, which may partly enable its outstanding tolerance against environmental changes.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

395. Life-history studies on infrapopulations of Mazocraes alosae (Monogenea) parasitising Alosa immaculata (Actinopterygii) in the northern Black and Azov Seas

Creator:
Plaksina, Mariana P., Gibson, David I., and Dmitrieva, Evgenija V.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
Fish parasite, infection indices, reproduction, season dynamics, influence of host and environment factors, Pontic shad, and fish migration
Language:
English
Description:
The life-history of Mazocraes alosae Hermann, 1782 on one of its hosts, the Pontic shad Alosa immaculata Bennett, is described for the first time. This anadromous fish, which occurs off the coast of the Crimea and migrates from the Black Sea to the Sea of Azov and into the River Don for spawning, was studied throughout its migration and during all seasons. It is demonstrated that the period of reproduction of this monogenean is significantly longer than that reported for the population in the Caspian Sea, lasting from April to November with a peak in April-May, and continues both in the sea and the river. Experiments showed that water salinity does not limit the development of the eggs or the hatching of the oncomiracidia. Our data reveal that the abundance of M. alosae is not determined by the size or sex of mature fish and that shad of less than two years old can also be infected with this monogenean, although less frequently than older fish. The direction of the migration of A. immaculata, either from the Black Sea to the Sea of Azov and into the rivers or in the opposite direction, does not influence the number of monogeneans present on the host. The main factor affecting the dynamics of the abundance of this monogenean is season, and, as has been indicated previously in the Caspian Sea basin, there is a synchronisation between the parasite's life-history and both the host's spawning behaviour and the duration of its migration.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

396. Light quality, oxygenic photosynthesis and more

Creator:
Lazar, D., Stirbet, A., Björn, L. O., and Govindjee, G.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
Chl fluorescence induction, chromatic acclimation of cyanobacteria, photoreceptors, photosynthetic pigments, photosystems I and II, and stomatal and chloroplast photoinduced movements
Language:
Multiple languages
Description:
Oxygenic photosynthesis takes place in thylakoid membranes (TM) of cyanobacteria, algae, and higher plants. It begins with light absorption by pigments in large (modular) assemblies of pigment-binding proteins, which then transfer excitation energy to the photosynthetic reaction centers of photosystem (PS) I and PSII. In green algae and plants, these light-harvesting protein complexes contain chlorophylls (Chls) and carotenoids (Cars). However, cyanobacteria, red algae, and glaucophytes contain, in addition, phycobiliproteins in phycobilisomes that are attached to the stromal surface of TM, and transfer excitation energy to the reaction centers via the Chl a molecules in the inner antennas of PSI and PSII. The color and the intensity of the light to which these photosynthetic organisms are exposed in their environment have a great influence on the composition and the structure of the light-harvesting complexes (the antenna) as well as the rest of the photosynthetic apparatus, thus affecting the photosynthetic process and even the entire organism. We present here a perspective on 'Light Quality and Oxygenic Photosynthesis', in memory of George Christos Papageorgiou (9 May 1933-21 November 2020; see notes a and b). Our review includes (1) the influence of the solar spectrum on the antenna composition, and the special significance of Chl a; (2) the effects of light quality on photosynthesis, measured using Chl a fluorescence; and (3) the importance of light quality, intensity, and its duration for the optimal growth of photosynthetic organisms.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

397. Limiting steps and the contribution of alternative electron flow pathways in the recovery of the photosynthetic functions after freezing-induced desiccation of Haberlea rhodopensis

Creator:
Georgieva, K., Popova, A. V. , Mihailova, G., Ivanov, A. G., and Velitchkova, M.
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
alternative electron flow, chlorophyll fluorescence, cyclic electron flows, freezing-induced desiccation, and rehydration
Language:
Multiple languages
Description:
Haberlea rhodopensis Friv. is unique with its ability to survive desiccation to an air-dry state during periods of extreme drought and freezing temperatures. To understand its survival strategies, it is important to examine the protective mechanisms not only during desiccation but also during rehydration. We investigated the involvement of alternative cyclic electron pathways during the recovery of photosynthetic functions after freezing-induced desiccation. Using electron transport inhibitors, the role of PGR5-dependent and NDH-dependent PSI-cyclic electron flows and plastid terminal oxidase were assessed during rehydration of desiccated leaves. Recovery of PSII and PSI, the capacity of PSI-driven cyclic electron flow, the redox state of plastoquinone pool, and the intersystem electron pool were analyzed. Data showed that the effect of alternative flows is more pronounced in the first hours of rehydration. In addition, the NDH-dependent cyclic pathway played a more determining role in the recovery of PSI than in the recovery of PSII.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

398. Lion-tailed macaques show a stable direction and reinforcement of hand preference in simple reaching tasks over several years

Creator:
Kuběnová, Barbora, Lhota, Stanislav, Tomanová, Veronika, Blažek, Vladimír, and Konečná, Martina
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
handedness, hand use, laterality, unimanual behaviour, and Macaca silenus
Language:
English
Description:
Research on hand preference in non-human primates provides information about the evolutionary origin of population-level bias of human handedness. Human hand preference has been shown to remain stable throughout an individual's lifespan. However, the stability of hand preference and its change with age in non-human primates remains questionable. We recorded hand use in lion-tailed macaques (Macaca silenus) during simple reaching tasks in three time periods over six years. We tested the effect of age and body posture on the direction and strength of hand preference in 23 observed individuals. In a subsample of 13 individuals followed for two or three subsequent time periods, we assessed the stability of hand preference across study periods. The direction of hand preference was highly stable; we detected no individuals changing from a left- to right-, or right- to left- preference and repeated quantitative measures of hand preference were correlated among subsequent study periods. Hand preference was, however, reinforced in older individuals and an individual's hand preference was stronger in postures with both hands free for foraging. Stable hand preference at an individual level, and its reinforcement over an individual's lifetime, is emerging as a robust finding across the primate order.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

400. Long-term monitoring of the impact of mining operations on the ground surface at the regional scale based on the InSAR-SBAS technique, the Upper Silesian Coal Basin (Poland). Case study

Creator:
Kopeć, Anna, Bugajska, Natalia, Milczarek, Wojciech, and Głąbicki, Dariusz
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
InSAR, subsidence, regional scale monitoring, and Sentinel 1A/1B
Language:
English
Description:
Underground mining activity in the region of the Upper Silesian Coal Basin (USCB) results in ground displacements scattered on a large area. Both the locations and the velocities of the displacements depend on many factors, such as the current location of the mining front, the mining depth and system, as well as geological conditions. Although SAR interferometry techniques allow the monitoring of such ground displacements, in a regional scale (as is the case of the USCB) SAR images must be appropriately processed (from a number of frames and swaths), and this is the problem addressed in this article. The implementation of algorithms for analyzing time series allows observations of displacements in both time and space. The authors also analyze the influence of mining operations on the road infrastructure and mining waste heaps located in the area and investigate the potential for the monitoring of secondary influence (due to induced seismic tremors). As a result of these investigations, the article presents the quality of the InSAR-SBAS data and the potential for their employment in the measurements.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

Limit your search

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »

View distribution

Current results range from 2012 to 2020

View larger »