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111.
Repeated intraspecific divergence in life span and aging of African annual fishes along an aridity gradient 下载免费PDF全文
Radim Blažek Matej Polačik Petr Kačer Alessandro Cellerino Radomil Řežucha Caroline Methling Oldřich Tomášek Kamila Syslová Eva Terzibasi Tozzini Tomáš Albrecht Milan Vrtílek Martin Reichard 《Evolution; international journal of organic evolution》2017,71(2):386-402
Life span and aging are substantially modified by natural selection. Across species, higher extrinsic (environmentally related) mortality (and hence shorter life expectancy) selects for the evolution of more rapid aging. However, among populations within species, high extrinsic mortality can lead to extended life span and slower aging as a consequence of condition‐dependent survival. Using within‐species contrasts of eight natural populations of Nothobranchius fishes in common garden experiments, we demonstrate that populations originating from dry regions (with short life expectancy) had shorter intrinsic life spans and a greater increase in mortality with age, more pronounced cellular and physiological deterioration (oxidative damage, tumor load), and a faster decline in fertility than populations from wetter regions. This parallel intraspecific divergence in life span and aging was not associated with divergence in early life history (rapid growth, maturation) or pace‐of‐life syndrome (high metabolic rates, active behavior). Variability across four study species suggests that a combination of different aging and life‐history traits conformed with or contradicted the predictions for each species. These findings demonstrate that variation in life span and functional decline among natural populations are linked, genetically underpinned, and can evolve relatively rapidly. 相似文献
112.
Hypertext atlas of fetal and neonatal pathology is a free resource for pregraduate students of medicine, pathologists and other health professionals dealing with prenatal medicine. The atlas can be found at http://www.muni.cz/atlases. The access is restricted to registered users. Concise texts summarize the gross and microscopic pathology, etiology, and clinical signs of both common and rare fetal and neonatal conditions. The texts are illustrated with over 300 images that are accompanied by short comments. The atlas offers histological pictures of high quality. Virtual microscope interface is used to access the high-resolution histological images. Fetal ultrasound video clips are included. Case studies integrate clinical history, prenatal ultrasonographic examination, gross pathology and histological features. The atlas is available in English (and Czech) and equipped with an active index. The atlas is suitable both for medical students and pathologists as a teaching and reference tool. The atlas is going to be further expanded while keeping the high quality of the images. 相似文献
113.
114.
Abstract The research conducted here presents a syntaxonomical revision of the montane mesophilous meadows of the Polygono bistortae-Trisetion flavescentis alliance in central Europe – the Slovak part of the western and eastern Carpathians. These typical semi-natural grasslands occur mainly as small islands over the calcareous bedrocks. Associations of this alliance have tight relationships to the Arrhenatherion, Mesobromion and Nardo-Agrostion alliances. Formal definitions based on combination of the species groups were used regarding the diversity and geographical range of the Polygono bistortae-Trisetion flavescentis alliance. Following the formal definitions from the eight associations reported previously for Slovakia, only four of them can be placed within the Polygono bistortae-Trisetion flavescentis: Campanulo glomeratae-Geranietum sylvatici, Geranio sylvatici-Trisetetum, Crepido mollis-Agrostietum capillaries and Geranio-Alchemilletum crinitae. A comparison of traditional and formalized classification, and the advantages/disadvantages of the formalized classification are discussed. 相似文献
115.
Eva Kiessling Sarah Nötzli Vyara Todorova Merima Forny Matthias R. Baumgartner Marijana Samardzija Jakub Krijt Viktor Kožich Christian Grimm D. Sean Froese 《生物化学与生物物理学报:疾病的分子基础》2021,1867(10):166201
Combined methylmalonic aciduria with homocystinuria (cblC type) is a rare disease caused by mutations in the MMACHC gene. MMACHC encodes an enzyme crucial for intracellular vitamin B12 metabolism, leading to the accumulation of toxic metabolites e.g. methylmalonic acid (MMA) and homocysteine (Hcy), and secondary disturbances in folate and one-carbon metabolism when not fully functional. Patients with cblC deficiency often present in the neonatal or early childhood period with a severe multisystem pathology, which comprises a broad spectrum of treatment-resistant ophthalmological phenotypes, including retinal degeneration, impaired vision, and vascular changes. To examine the potential function of MMACHC in the retina and how its loss may impact disease, we performed gene expression studies in human and mouse, which showed that local expression of MMACHC in the retina and retinal pigment epithelium is relatively stable over time. To study whether functional MMACHC is required for retinal function and tissue integrity, we generated a transgenic mouse lacking Mmachc expression in cells of the peripheral retina. Characterization of this mouse revealed accumulation of cblC disease related metabolites, including MMA and the folate-dependent purine synthesis intermediates AICA-riboside and SAICA-riboside in the retina. Nevertheless, fundus appearance, morphology, vasculature, and cellular composition of the retina, as well as ocular function, remained normal in mice up to 6 or 12 months of age. Our data indicates that peripheral retinal neurons do not require intrinsic expression of Mmachc for survival and function and questions whether a local MMACHC deficiency is responsible for the retinal phenotypes in patients. 相似文献
116.
Radovan Smolinský Lumír Gvoždík 《Biological journal of the Linnean Society. Linnean Society of London》2013,108(1):109-115
Many organisms respond to the heterogeneity of abiotic environmental conditions by plastic modifications of their phenotypes (acclimation or acclimatization). Despite considerable research efforts in this area, the beneficial (adaptive) effect of acclimation or acclimatization is still debated. We examined whether the development of newt larvae (Ichthyosaura alpestris) under different natural light and thermal conditions subsequently altered their susceptibility to predation in sun‐exposed versus shaded tanks in nature. During predation trials in various light and temperature conditions, newt larvae that developed in sun‐exposed warmer tanks consistently suffered from higher predation by dragonfly nymphs (Aeshna cyanea) compared to larvae from shaded or colder tanks. We conclude that higher sun exposure during embryonic and larval development negatively affects antipredator performance even in sun‐exposed tanks: this result is inconsistent with the beneficial acclimation hypothesis. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ●● , ●●–●●. 相似文献
117.
Nucleoside analogues are chemical means to investigate hydrogen bonds, base stacking, and solvation as the three predominant forces that are responsible for the stability of secondary structure of nucleic acids. To obtain deeper insight into the contributions of these interactions to RNA stability apart from the ones exerted by the predominant nucleosides we decided to synthesize some novel nucleic acid analogues where the nucleobases are replaced by fluoroindoles. Fluorinated indoles can be compared to fluorinated benzimidazoles to determine the role of nitrogen in five membered ring system. The synthesis of fluoroindole ribonucleosides is described here. 相似文献
118.
Summary In this study, immunohistochemistry for neuronal nitric oxide synthase (bNOS-IR), nicotinamide adenine dinucleotide phosphate
diaphorase histochemistry (NADPHd) and nitric oxide synthase radioassay were used to study the occurrence, number and distribution
pattern of nitric oxide synthesizing neurons in the lumbar (L1–L7) and sacral (S1–S3) dorsal root ganglia of the dog. Nitric
oxide synthase immunolabelling was present in a large number of small- (area <1000 μm2) and medium-sized (area 1000–2000 μm2) as well as in a limited number of large-sized (area >2000 μm2) neurons. Although neuronal nitric oxide synthase immunolabelling and histochemical staining provided intense staining of
multiple small- and medium-sized neurons in all lumbar and sacral dorsal root ganglia, immunolabelled or histochemically stained
somata exhibited little topographic distribution in individual dorsal root ganglia. Great heterogeneity was noticed in the
immunolabelling of medium-sized nitric oxide synthase immunopositive neurons ranging from lightly immunolabelled somata to
heavily immunoreactive ones with completely obscured nuclei. Both staining procedures proved to be highly effective in visualizing
intraganglionic fibers of various diameters. In general, the largest fibers revealed at the peripheral end of lumbar and sacral
dorsal root ganglia were larger, 6.49–9.35 μm in diameter, while those running centrally and proceeding into the dorsal roots
were about 30% reduced, ranging between 5.32 and 8.67 μm in diameter. Peripherally, the occurrence of nitric oxide synthase
detected in axonal profiles, and confirmed histochemically, in the specimens of the femoral and sciatic nerves, is the first
indication of the presence of nitric oxide synthase in the peripheral processes of somata located in L4–S2 dorsal root ganglia.
Large and thin central nitric oxide synthase immunoreactive processes of L1–S3 dorsal root ganglion neurons segregate shortly
before entering the spinal cord, the former making a massive medial bundle in the dorsal root accompanied by a slim lateral
bundle penetrating Lissauer's tract. Quantitative assessment of the distribution of bNOS-IR and/or NADPHd-stained neurons
showed a peculiar pattern in relation to spinal levels. Apparent incongruity was found in the total number of NADPHd-stained
versus bNOS-IR neurons, demonstrating a clear prevalence of small bNOS-IR somata in all lumbar ganglia, while medium-sized
NADPHd-stained somata clearly prevailed all along the rostrocaudal axis with a peak in L5 ganglion. While the number of small
bNOS-IR neurons clearly outnumbered NADPHd-stained and NADPHd-unstained somata in S1–S3 ganglia, an inverse relation appeared
comparing the total number of medium-sized NADPHd-stained and NADPHd-unstained somata compared with the number of moderate
and intense bNOS-IR neurons. Densitometry of bNOS-IR and NADPHd-stained neurons in lumbar and sacral ganglia revealed two
distinct subsets of densitometric profiles, one relating to more often found medium-sized bNOS immunolabelled and the other,
characteristic for moderately bNOS immunoreactive somata of the same cell size. Considerable differences in catalytic nitric
oxide synthase activity, determined by conversion of [3H]arginine to [3H]citrulline were obtained in lumbosacral dorsal root ganglia all along the lumbosacral intumescence, the lowest (0.898± 0.2
dpm/min/μg protein) being in the L4 dorsal root ganglion and the highest (4.194± 0.2 dpm/min/μg protein) in the S2 dorsal
root ganglion. 相似文献
119.
Mart Roosimaa Taavi Põdramägi Lumme Kadaja Arno Ruusalepp Kalju Paju Raivo Puhke Margus Eimre Ehte Orlova Andres Piirsoo Nadežda Peet Frank N. Gellerich Enn Seppet 《Mitochondrion》2013,13(5):399-409
Cardiac energy metabolism with emphasis on mitochondria was addressed in atrial tissue from patients with overload-induced atrial dilation. Structural remodeling of dilated (D) atria manifested as intracellular accumulation of fibrillar aggregates, lipofuscin, signs of myolysis and autophagy. Despite impaired complex I dependent respiration and increased diffusion restriction for ADP, no changes regarding adenylate and creatine kinase occurred. We observed 7-fold overexpression of HK2 gene in D atria with concomitant 2-fold greater activation of mitochondrial oxygen consumption by glucose, which might represent an adaption to increased energy requirements and impaired mitochondrial function by effectively joining glycolysis and oxidative phosphorylation. 相似文献
120.
Jiří Masojídek Giuseppe Torzillo Michal Koblížek Jiří Kopecký Paola Bernardini Angelo Sacchi Josef Komenda 《Planta》1999,209(1):126-135
The role of the xanthophyll cycle in the adaptation of two chlorococcal algae Scenedesmus quadricauda and Chlorella sorokiniana to high irradiance was studied under laboratory and outdoor conditions. We wished to elucidate whether the xanthophyll cycle
plays a key role in dissipating the excesses of absorbed light, as in higher plants, and to characterise the relationship
between chlorophyll fluorescence parameters and the content of xanthophyll-cycle pigments. The xanthophyll cycle was found
to be operative in both species; however, its contribution to overall non-photochemical quenching (NPQ) could only be distinguished
in Scenedesmus (15–20% of total NPQ). The Scenedesmus cultures showed a larger pool of xanthophyll-cycle pigments than Chlorella, and lower sensitivity to photoinhibition as judged from the reduction of maximum quantum yield of photosystem II. In general,
both algae had a larger xanthophyll-cycle pool when grown outdoors than in laboratory cultures. Comparing the two species,
Scenedesmus exhibited a higher capacity to adapt to high irradiance, due to an effective quenching mechanism and high photosynthetic
capacity; in contrast, Chlorella represents a species with a larger antennae system, less-efficient quenching and lower photosynthetic performance. Non-photochemical
quenching (NPQ) induced through the xanthophyll cycle can, to a limited extent, represent a regulatory factor in diluted algal
cultures grown in outdoor solar photobioreactors, as well as in natural algal phytoplankton populations exposed transiently
to high irradiance. However, it does not play an appreciable role in dense, well-mixed microalgal suspensions.
Received: 6 August 1998 / Accepted: 12 February 1999 相似文献