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292. Adaptation of the heart to hypertension is associated with maladaptive gap junction connexin-43 remodeling

Creator:
Marcela Fialová, Katarína Dlugošová, Ľudmila Okruhlicová, Kristek, F., Manoach, M., and Narcisa Tribulová
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, hypertenze, srdeční arytmie, physiology, hypertension, cardiac arrhythmia, gap junction remodeling, connexin-43, malignant arrhythmias, 14, and 612
Language:
English
Description:
We hypothesized that hypertension-related myocardial remodeling characterized by hypertrophy and fibrosis might be accompanied by cell-to-cell gap junction alterations that may account for increased arrhythmogenesis. Intercellular junctions and expression of gap junction protein connexin-43 were analyzed in rat heart tissues from both spontaneous (SHR) and L-NAME model of hypertension. Isolated heart preparation was used to examine susceptibility of the heart to lethal ventricular fibrillation induced by low potassium perfusion. Ultrastructure observation revealed enhanced neoformation of side-to-side type while internalization of end-to-end type (intercalated disc-related) of gap junctions prevailed in the myocardium of rats suffering from either spontaneous or L-NAME-induced hypertension. In parallel, immunolabeling showed increased number of connexin-43 positive gap junctions in lateral cell membrane surfaces, particularly in SHR. Besides, focal loss of immunopositive signal was observed more frequently in hearts of rats treated with L-NAME. There was a significantly higher incidence of hypokalemia-induced ventricular fibrillation in hypertensive compared to normotensive rat hearts. We conclude that adaptation of the heart to hypertension-induced mechanical overload results in maladaptive gap junction remodeling that consequently promotes development of fatal arrhythmias., M. Fialová, K. Dlugošová, L. Okrouhlicová, F. Kristek, M. Manoach, N. Tribulová., and Obsahuje bibliografii a biblioigrafické údaje
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

293. Adaptation strategies of two leaf cohorts of Prosopis juliflora produced in spring and monsoon

Creator:
Shirke, P. A., Pathre, U. V., and Sane, P. V.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
asimilace uhlíku, carbon assimilation, carboxylation efficiency, dark respiration rate, quantum efficiency, tree photosynthesis, water-use efficiency, 2, and 581
Language:
Multiple languages
Description:
Prosopis juliflora is an invasive leguminous tree species growing profusely under wide environmental conditions. Primary objective of this study was to investigate adaptation strategies evolved to deal with wide environmental conditions during different seasons. P. juliflora adapts through a production of leaves in two seasons, namely, the spring (the first cohort) and monsoon (the second cohort) with differing but optimal physiological characteristics for growth in respective seasons. Our studies show that the first cohort of leaves exhibit maximum carbon fixation under moderate temperatures and a wide range of PPFD. However, these leaves are sensitive to high leaf-to-air-vapor pressure deficit (VPD) occurring at high temperatures in summer resulting in senescence. While the second cohort of leaves produced during monsoon showed maximum carbon fixation at high irradiance and temperatures with low VPD, it is sensitive to low temperatures causing senescence in winter., P. A. Shirke, U. V. Pathre, P. V. Sane., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

294. Adaptive photosynthetic and physiological responses to drought and rewatering in triploid Populus populations

Creator:
Liao, T., Wang, Y., Xu, C. P., Li, Y., and Kang, X. Y.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
topol, populace (biologie), poplar, population (biology), chlorofylová fluorescence, výměna plynu, malondialdehyd, stomatální omezení, deficit vody, sucho, chlorophyll fluorescence, gas exchange, malondialdehyde, stomatal limitation, water deficit, drought, 2, and 581
Language:
Multiple languages
Description:
Cuttings of Populus cathayana Rehd, originating from three triploid and one diploid populations with the same parents but different gamete origins, were used to examine physiological responses to drought stress and rewatering by exposure to three progressive water regimes. Progressive drought stress significantly decreased the leaf relative water content (RWC), photosynthesis, and chlorophyll fluorescence parameters, and increased the relative electrolyte leakage, malondialdehyde (MDA), free proline (Pro), and antioxidant enzymes, such as superoxide dismutase, peroxidase, and catalase, in the four populations evaluated. However, compared to the diploid population, triploid populations showed lower relative electrolyte leakage and MDA, higher RWC and Pro content, and more efficient photosynthesis and antioxidant systems under the same water regime. Our data indicated that triploid populations possessed more efficient protective mechanisms than that of diploid population with gradually increasing drought stress. Moreover, some triploid genotypes were less tolerant to water stress than that of diploids due to large intrapopulation overlap., T. Liao, Y. Wang, C. P. Xu, Y. Li, X. Y. Kang., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

295. Adaptive properties of the plant pigment systems

Creator:
Maslova, T.G. and Popova, I.A.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
Analysis of the contents and organization of pigments in leaves of more than 60 plant species from different natural habitats revealed that the majority of plants from extreme regions had a low pigment content. The arctic plants contained 40-60 % less chlorophyll (Chl) than the same species in the temperate zone. The desert plants had an extremely low pigment content. Owing to high amount of total carotenoids (Car), the arctic and high montane plants had the lowest ratios Chl/Car. The part of Chl belonging to light-harvesting (LH)-antenna varied less than the total amounts. The majority of investigated arctic plants had a smaller amount of Chl and larger part of it in the LH-antenna than plants of the temperate zone. The pigment apparatus of high montane plants was distinguished by very high Car content probably serving as protectant against photodamage: in their photosystems 1 and 2 there was 4-5 times more p-carotene than in the plants of other zones.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

296. Adaptive significance of the prolonged diapause in the western Mediterranean lycaenid butterfly Tomares ballus (Lepidoptera: Lycaenidae)

Creator:
Obregón, Rafael, Haeger, Juan Fernández, and Jordano, Diego
Format:
print, počítač, and online zdroj
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Zoologie, konkurence, motýli, competition, butterflies, Lepidoptera, Lycaenidae, Tomares ballus, prolonged diapause, evolutive adaptation, changing environment, parasitoids, 2, and 59
Language:
English
Description:
Diapause is a common dormancy strategy exhibited by many species of invertebrates and insects to temporarily avoid seasonally recurring unfavourable conditions for their development, most usually in winter. Less frequently, a prolonged diapause lasting two or more years is described in species living in unpredictable environments where it is adaptive, but with significant costs. In this paper we examine the occurrence of prolonged diapause in the lycaenid butterfly Tomares ballus. Pupae of this species undergo an obligate diapause from mid-May to late January the following year. However, during our rearing experiments (from 2009 to 2016) the emergence of adults occurred sequentially and a fraction of the pupae remained in diapause for up to seven years. The annual percentage emergence after the first year of diapause was 45.6%, and only barely exceeded 50.0% in 2015. Remarkably, 12 pupae (11.4% of the initial brood) remained in diapause in their eighth year. The negative exponential equation fitted to the emergence data suggests that further emergences may occur within the next five years. Therefore, the potential for successful prolonged diapause of T. ballus pupae may be more than 10 years. The adaptive value of this strategy is discussed in relation to the effects of adverse and unpredictable weather during the flight period of the butterfly, intra-guild competition, parasitoids and changes in habitat quality. We suggest that this strategy may also be exhibited by other species of Mediterranean lycaenids., Rafael Obregón, Juan Fernández Haeger, Diego Jordano., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

297. Adaptivní optika v astronomii

Creator:
Řeháček, Jaroslav and Stoklasa, Bohumil
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyzika, astronomie, adaptivní optika, physics, astronomy, optics, 6, and 53
Language:
Czech and English
Description:
Adaptavní optické systémy se vyznačují schopností měnit své optické vlastnosti na požádání a v reálném čase. V tomto příspěvku jsou diskutovány základní prvky adaptivních optických systémů využívaných v astronomii ke kompenzaci vlivu atmosféry na zobrazení velkých pozemských teleskopů., Adaptive optical systems are those whose optical responses can be adjusted on demand, in real time. Here we discuss the basics of adaptive optical systems utilised in astronomy for compensation of aberrations due to atmospheric turbulence, which seriously impairs the performance of uncorrected large ground-based telescopes., Jaroslav Řeháček, Bohumil Stoklasa., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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