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971.
972.
973.
Evgeniia Prokhorova Thomas Agnew Anne R. Wondisford Michael Tellier Nicole Kaminski Danique Beijer James Holder Josephine Groslambert Marcin J. Suskiewicz Kang Zhu Julia M. Reber Sarah C. Krassnig Luca Palazzo Shona Murphy Michael L. Nielsen Aswin Mangerich Dragana Ahel Jonathan Baets Ivan Ahel 《Molecular cell》2021,81(12):2640-2655.e8
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974.
975.
Yeghiazaryan M Żybura-Broda K Cabaj A Włodarczyk J Sławińska U Rylski M Wilczyński GM 《Histochemistry and cell biology》2012,138(1):75-87
Matrix metalloproteinases (MMPs) are key regulators of extracellular matrix remodeling, but have also important intracellular targets. The purpose of this study was to examine the activity and subcellular localization of the gelatinases MMP-2 and MMP-9 in skeletal muscle of control and physically trained rats. In control hind limb muscle, the activity of the gelatinases was barely detectable. In contrast, after 5 days of intense exercise, in Soleus (Sol), but not Extensor digitorum longus (EDL) muscle, significant upregulation of gelatinolytic activity in myofibers was observed mainly in the nuclei, as assessed by high resolution in situ zymography. The nuclei of quiescent satellite cells did not contain the activity. Within the myonuclei, the gelatinolytic activity colocalized with an activated RNA Polymerase II. Also in Sol, but not in EDL, there were few foci of mononuclear cells with strongly positive cytoplasm, associated with apparent necrotic myofibers. These cells were identified as activated satellite cells/myoblasts. No extracellular gelatinase activity was observed. Gel zymography combined with subcellular fractionation revealed training-related upregulation of active MMP-2 in the nuclear fraction, and increase of active MMP-9 in the cytoplasmic fraction of Sol. Using RT-PCR, selective increase in MMP-9 mRNA was observed. We conclude that training activates nuclear MMP-2, and increases expression and activity of cytoplasmic MMP-9 in Sol, but not in EDL. Our results suggest that the gelatinases are involved in muscle adaptation to training, and that MMP-2 may play a novel role in myonuclear functions. 相似文献
976.
Knapik AA Petkowski JJ Otwinowski Z Cymborowski MT Cooper DR Majorek KA Chruszcz M Krajewska WM Minor W 《Proteins》2012,80(10):2359-2368
The rut pathway of pyrimidine catabolism is a novel pathway that allows pyrimidine bases to serve as the sole nitrogen source in suboptimal temperatures. The rut operon in E. coli evaded detection until 2006, yet consists of seven proteins named RutA, RutB, etc. through RutG. The operon is comprised of a pyrimidine transporter and six enzymes that cleave and further process the uracil ring. Herein, we report the structure of RutD, a member of the α/β hydrolase superfamily, which is proposed to enhance the rate of hydrolysis of aminoacrylate, a toxic side product of uracil degradation, to malonic semialdehyde. Although this reaction will occur spontaneously in water, the toxicity of aminoacrylate necessitates catalysis by RutD for efficient growth with uracil as a nitrogen source. RutD has a novel and conserved arrangement of residues corresponding to the α/β hydrolase active site, where the nucleophile's spatial position occupied by Ser, Cys, or Asp of the canonical catalytic triad is replaced by histidine. We have used a combination of crystallographic structure determination, modeling and bioinformatics, to propose a novel mechanism for this enzyme. This approach also revealed that RutD represents a previously undescribed family within the α/β hydrolases. We compare and contrast RutD with PcaD, which is the closest structural homolog to RutD. PcaD is a 3‐oxoadipate‐enol‐lactonase with a classic arrangement of residues in the active site. We have modeled a substrate in the PcaD active site and proposed a reaction mechanism. Proteins 2012;. © 2012 Wiley Periodicals, Inc. 相似文献
977.
Magdalena Markowicz Pawe? Szymański Marcin Ciszewski Arkadiusz K?ys El?bieta Mikiciuk-Olasik 《Journal of biological physics》2012,38(4):637-656
The interactions between dendrimers and different types of drugs are nowadays one of the most actively investigated areas of the pharmaceutical sciences. The interactions between dendrimers and drugs can be divided into: internal encapsulation, external electrostatic interaction, and covalent conjugation. In the present study, we investigated the potential of poly(amidoamine) (PAMAM) dendrimers for solubility of four iminodiacetic acid derivatives. We reported that PAMAM dendrimers contribute to significant solubility enhancement of iminodiacetic acid analogues. The nature of the dendrimer–drug complexes was investigated by 1H NMR and 2D-NOESY spectroscopy. The 1H NMR analysis proved that the water-soluble supramolecular structure of the complex was formed on the basis of ionic interactions between terminal amine groups of dendrimers and carboxyl groups of drug molecules, as well as internal encapsulation. The 2D-NOESY analysis revealed interactions between the primary amine groups of PAMAM dendrimers and the analogues of iminodiacetic acid. The results of solubility studies together with 1H NMR and 2D-NOESY experiments suggest that the interactions between PAMAM dendrimers of generation 1–4 and derivatives of iminodiacetic acid are based on electrostatic interactions and internal encapsulation. 相似文献
978.
Štěpán Janeček Jan Riegert Ondřej Sedláček Michael Bartoš David Hořák Jiří Reif Eliška Padyšáková Drahomíra Fainová Marcin Antczak Michal Pešata Václav Mikeš Eliška Patáčová Jan Altman Jana Kantorová Záboj Hrázský Jakub Brom Jiří Doležal 《Biological journal of the Linnean Society. Linnean Society of London》2012,107(2):355-367
Community‐level studies have shown that plant–pollinator interactions are much more generalized than previously expected. Consequently, many authors have questioned the significance of phenotypic complementarity between plants and pollinators and abundance effects in pollination interactions. Here, we compare the behaviour of three sunbird species feeding on the nectar of five plant species in afromontane vegetation. We studied the feeding behaviour with and without consideration of plant abundance (i.e. diet selectivity and diet composition, respectively). The aims of the study were to estimate: (1) how relative resource abundance influences flower selectivity; (2) the degree of phenotypic matching; and (3) whether different plant resource assessment methods give different answers to this question. The results showed that, although sunbirds frequently feed on both morphologically adapted and nonadapted plants, food selectivity data are consistent with the hypothesis of phenotypic complementarity. Moreover, we found that the type of plant abundance measurement can change conclusions in some cases, as individual plants differ in their growth habits and nectar production. This effect was most obvious for the assessment of selectivity of the northern double‐collared sunbird (Cinnyris reichenowi) and for Hypoestes aristata, a plant producing inflorescences composed of a large number of small flowers possessing small amounts of nectar per flower (a high abundance of flowers, but a low abundance of nectar relative to the remaining plant community). © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??. 相似文献
979.
Marcin Nobis 《Nordic Journal of Botany》2012,30(1):70-76
Stipa narynica M. Nobis sp. nov. from the western Tian‐Shan Mts (western Kyrgyzstan) is described and illustrated. The new species belongs to sect. Smirnovia Tzvel. Morphologically the species is similar to S. aktauensis, a species from which it is easily distinguished by its longer glumes (41–)44–55(–62) mm vs 35–45 mm, longer anthecium (11.5–) 12.0–14.2(–14.8) mm vs 9.5–11.2(–11.7) mm, longer hairs on the seta (5.5–)6.0–8.0(–8.5) mm vs (3.0–)3.8–5.5(–6.0) mm and by the top of the lemma which in S. narynica is either glabrous or with a poorly developed ring of short hairs, while in S. aktauensis, the top of lemma is always distinctly and densely pilose. The lemma and leaf blade structure of both species were examined by means of SEM. The main features differentiating S. narynica and S. aktauensis and distribution of the taxa are presented. An original key to the middle Asiatic species of the sect. Smirnovia, the most similar to Stipa narynica is provided. 相似文献
980.
Gierach M Gierach J Skowrońska A Rutkowska E Spychalska M Pujanek M Junik R 《Endokrynologia Polska》2012,63(1):14-17