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1573. Rakovinná buňka a změny jejího metabolismu: cesta k přežití i nástroj k destrukci

Creator:
Slaninová, Věra and Krejčí, Alena
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Obecná biologie, nádorové buňky, metabolismus, 2, and 57
Language:
Czech
Description:
There is one feature common to most types of cancer - profound changes in their cellular metabolism that accommodate the high requirements for fast growth and cell division. This change brings about many advantages to the transformed cell and it is also indispensable for its survival and proliferation. This review describes the differences in metabolism between normal and cancerous cells and outlines strategies that could exploit these differences as tools for oncological treatment. and Věra Slaninová, Alena Krejčí.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1574. Random or clumped: How litter dwelling scorpions are distributed in a fragment of Brazilian Atlantic forest

Creator:
Santos, Gabriela Cavalcanti Silva de Gusmão, Dionisio-Da-Silva, Welton, Souza-Alves, João Pedro, Albuquerque, Cleide Maria Ribeiro de, and Lira, André Felipe de Araujo
Format:
print, počítač, and online zdroj
Type:
model:article and TEXT
Subject:
štíři, demekologie, deštné lesy, scorpions, population ecology, rainforests, Brazílie, Brasil, Ananteris mauryi, Tityus (Archaeotityus) pusillus, Payandeh aggregation index, spatial distribution, 2, and 59
Language:
English
Description:
Knowledge of the patterns in the spatial distribution of species provides valuable information about the factors (resources and environment) that regulate the use of space by animals. Typically, the distribution of litter-dwelling scorpions in Atlantic forests is correlated with the structure of their microhabitats, although to better understand their natural history more studies on the patterns in their use of space are required. Therefore, we investigated the effect of rainfall on the patterns in the spatial distributions and population densities of two sympatric species of scorpion, Tityus (Archaeotityus) pusillus Pocock 1893 and Ananteris mauryi Lourenço 1982 in a fragment of Atlantic Forest in Brazil. The study was carried out during the dry (September) and rainy (June) months. We collected 501 individuals (268 T. (A.) pusillus and 233 A. mauryi) by actively searching at night using UV lanterns. We found that the spatial distribution and population density of T. (A.) pusillus, but not A. mauryi, were significantly affected by rainfall, with T. (A.) pusillus individuals showing a clumped pattern during the rainy month and random distribution in the dry month. We also found a different response in the population densities of the two species, with T. (A.) pusillus but not A. mauryi being affected by rainfall. Our results indicate that, although co-habiting in leaf litter, these species respond differently to rainfall, which affects their spatial distribution and abundance in this habitat., Gabriela Cavalcanti Silva de Gusmão Santos, Welton Dionisio-Da-Silva, João Pedro Souza-Alves, Cleide Maria Ribeiro de Albuquerque, André Felipe de Araujo Lira., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

1575. Rearrangement of leaf traits with changing source-sink relationship in blueberry (Vaccinium corymbosum L.) leaves

Creator:
Jorquera-Fontena, E., Alberdi, M., Reyes-Díaz, M., and Franck, N.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
uhlík, karotenoidy, ovoce, pigmenty, carbon, carotenoids, fruit, pigments, výměna plynu, fotosyntetické pigmenty, rozpustné cukry, borůvky, list, brusnice chocholičnatá, gas exchange, photosynthetic pigments, soluble sugars, nitrogen, blueberries, dark respiration rate, girdling, leaf, stomatal conductance, source-sink relationship, 2, and 581
Language:
Multiple languages
Description:
The source-sink relationship is one of major determinants of plant performance. The influence of reproductive sink demand on light-saturated photosynthesis (Pmax), dark respiration (RD), stomatal conductance (gs), intrinsic water-use efficiency (WUEi), contents of soluble sugar (SSC), nitrogen, carbon, and photosynthetic pigments was examined in blueberry (Vaccinium corymbosum L. cv. ‘Brigitta’) during the final stage of rapid fruit growth. Measurements were performed three times per day on developed, sun-exposed leaves of girdled shoots with 0.1, 1, and 10 fruit per leaf (0.1F:L, 1F:L, and 10F:L, respectively) and nongirdled shoots bearing one fruit per leaf (NG). Girdling and lower fruit amount induced lower Pmax, gs, N, and total chlorophyll (Chl) and higher WUEi, SSC, RD, Chl a/b ratio and carotenoids-to-chlorophylls ratio (Car/Chl) for the 1F:L and 0.1F:L treatments. The impact of girdling was counterbalanced by 10F:L, with NG and 10F:L having similar values. Variables other than Pmax, RD, gs, WUEi, and SSC were unaffected throughout the course of the day. Pmax and gs decreased during the course of the day, but gs decreased more than Pmax in the afternoon, while WUEi was increasing in almost all treatments. SSC increased from the morning until afternoon, whereas RD peaked at noon regardless of the treatment. Generally, Pmax was closely and negatively correlated to SSC, indicating that sugar-sensing mechanisms played an important role in regulation of blueberry leaf photosynthesis. With respect to treatments, Pmax and N content were positively related, while RD was not associated to substrate availability. The enhanced Car/Chl ratio showed a higher photoprotection under the lower sink demand. Changes in the source-sink relationship in 'Brigitta' blueberry led to a rearrangement of physiological and structural leaf traits which allowed adjusting the daily balance between carbon assimilation and absorbed light energy., E. Jorquera-Fontena, M. Alberdi, M. Reyes-Díaz, N. Franck., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1576. Recombinant expression, purification and characterization of Bombyx mori (Lepidoptera: Bombycidae) pyridoxal kinase

Creator:
Huang, Shuo-Hao, Ma, Wang, Zhang, Ping-Ping, Zhang, Jian-Yun, Xie, Yan-Feng, and Huang, Long-Quan
Type:
article, články, model:article, and TEXT
Subject:
Zoologie, entomologie, Bombyx mori, pyridoxal kinase, recombinant expression, purification, characterization, 2, and 59
Language:
English
Description:
Pyridoxal kinase (PLK; EC 2.7.1.35) is a key enzyme in the metabolism of vitamin B6 (VB6) in Bombyx mori. A fusion expressional vector pET-22b-BPLK-His was constructed using a sub-cloning technique, the recombinant B. mori PLK was then expressed in Escherichia coli, purified and characterized. Bioinformatics were used to deduce the protein structure and genomic organization of this enzyme. Using Ni Sepharose affinity column chromatography, the recombinant protein was purified to very high degree (approximately 90%). The recombinant PLK exhibits a high specific enzymatic activity (1800 nmol/min/mg of protein). The maximum catalytic activity of this enzyme was recorded over a narrow pH range (5.5-6.0) and Zn2+ is the most effective cation for catalysis under saturating substrate concentrations. When only triethanolamine is present as the cation, K+ is an activator of PLK. A double reciprocal plot of initial velocity suggests that the enzyme catalyses the reaction by means of a sequential catalytic mechanism. Under optimal conditions, the Km value for the substrates of ATP and pyridoxal are 57.9 ± 5.1 and 44.1 ± 3.9 µM. B. mori's genome contains a single copy of the PLK gene, which is 7.73 kb long and contains five exons and four introns, and is located on the eighth chromosome. The PLK may be a dimer with two identical subunits under native conditions, and it is hypothesized that each monomer contains eight α-helices (α1-8), nine β-strands (β1-9) and two segments of 310 helices. and Shuo-Hao HUANG, Wang MA, Ping-Ping ZHANG, Jian-Yun ZHANG, Yan-Feng XIE, Long-Quan HUANG.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

1577. Reconstructing a 55-million-year-old butterfly (Lepidoptera: Hesperiidae)

Creator:
De Jong, Rienk
Format:
print, počítač, and online zdroj
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Zoologie, evoluce (biologie), biogeografie, evolution (biology), biogeography, Fossil, oldest butterfly, Hesperiidae, Protocoeliades kristenseni, new genus, new species,, divergence time, 2, and 59
Language:
English
Description:
The oldest butterfly fossil known, which was formed about 55 Ma in what is now Denmark, is described. The fragments of its forewing venation indicates it belongs to the Hesperiidae. Further reconstruction indicates that it fits in the Coeliadinae and is close to the extant genera Hasora and Burara. It is here described as Protocoeliades kristenseni gen. et sp. n. It is the first butterfly fossil found on a continent (Europe) where its closest relatives do not currently occur. Its position on the phylogenetic tree of the Coeliadinae and its importance in understanding the time dimension in the evolution of butterflies, and their ecological and biogeographic implications are discussed., Rienk De Jong., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1578. Reduced Progesterone Metabolites in Human Late Pregnancy

Creator:
Miroslav Hill, Antonín Pařízek, Radmila Kancheva, and Jan Evangelista Jirásek
Type:
article, články, model:article, and TEXT
Subject:
Biologické vědy, fyziologie, physiology, neuroactive steroids, pregnancy, plasma, metabolome, GC-MS, 2, and 57/59
Language:
English
Description:
In this review, we focused on the intersection between steroid metabolomics, obstetrics and steroid neurophysiology to give a comprehensive insight into the role of sex hormones and neuroactive steroids (NAS) in the mechanism controlling pregnancy sustaining. The data in the literature including our studies show that there is a complex mechanism providing synthesis of either pregnancy sust aining or parturition provoking steroids. This mechanism includes the boosting placental synthesis of CRH with approaching parturition inducing the excessive synthesis of 3β-hydroxy-5-ene steroid sulfates serving primarily as precursors for placental synthesis of progestogens, estrogens and NAS. The distribution and changing activities of placental oxidoreductases are responsible for the activation or inactivation of the aforementioned steroids, which is compartment-specific (maternal and fetal compartments) and dependent on gestational age, with a tendency to shift the production from the pregnancy-sustaining steroids to the parturition provoking ones with an increasing gestational age. The fetal and maternal livers catabolize part of the bioactive steroids and also convert some precursors to bioactive steroids. Besides the progesterone, a variety of its 5α/β-reduced metabolites may significantly influence the maintenance of human pregnancy, provide protection against excitotoxicity following acute hypoxic stress, and might also affect the pain perception in mother and fetus. and M. Hill ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1579. Reduction of photosynthetic apparatus plays a key role in survival of the microalga Haematococcus pluvialis (Chlorophyceae) at freezing temperatures

Creator:
Chekanov, K., Vasilieva, S., Solovchenko, A., and Lobakova, E.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, cold stress, Haematococcys pluvialis, stress tolerance, 2, and 581
Language:
Multiple languages
Description:
The microalga Haematococcus pluvialis is a biotechnologically important microorganism producing a ketocarotenoid astaxanthin. Haematococcus exists either as metabolically active vegetative cells with a high chlorophyll content or astaxanthin-rich haematocysts (aplanospores). This microalga featuring outstanding tolerance to a wide range of adverse conditions is a highly suitable model for studies of freezing tolerance in phototrophs. The retention of H. pluvialis cell viability after freezing-thawing is ascribed to elevated antioxidant enzyme activity and high ketocarotenoid content. However, we report that only haematocysts characterized by a lower photosynthetic activity were resistant to freezing-thawing even without cryoprotectant addition. The key factors of haematocyst freezing tolerance were assumed to be a low water content, rigid cell walls, reduction of the membranous structures, photosynthesis downregulation, and low chlorophyll content. Collectively, viability of Haematoccus after freezing-thawing can be improved by forcing the transition of vegetative cells to freeze-tolerant haematocysts before freezing., K. Chekanov, S. Vasilieva, A. Solovchenko, E. Lobakova., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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