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91.
Artacho P Soto-Gamboa M Verdugo C Nespolo RF 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,147(4):1060-1066
Living organisms are continuously faced with several forms of environmental perturbation, one of the most important being human activity. In this scenario, the role of physiological studies on wildlife has proved to be important given that in vivo physiological variables reflect a great deal how sensitive animals are to acute environmental changes. We studied the haematological parameters in black-necked swans (Cygnus melanocoryphus) at the Ramsar site at the Carlos Anwandter Sanctuary, which were experiencing a drastic population decrease. Through seven months, body mass (body mass corrected by total length) was reduced 30%, which was followed by significant reductions of haemoglobin concentration, haematocrit and red blood cell count. Mean cell volume and mean cell haemoglobin concentration did not change with time, whereas there was a significant increase of the white blood cells and heterophile / lymphocyte ratio. Our results, together with the published evidence, suggests that the proximal factors associated with the mass mortality and emigration of the black - necked swan population at the "Carlos Anwandter Sanctuary" was a drastic nutritional deficiency, and the potentially toxic effects of iron pollution in the waters of the Ramsar site. 相似文献
92.
93.
Heidi Gytz Durita Mohr Paulina Seweryn Yuichi Yoshimura Zarina Kutlubaeva Fleur Dolman Bosene Chelchessa Alexander B. Chetverin Frans?A.?A. Mulder Ditlev E. Brodersen Charlotte R. Knudsen 《Nucleic acids research》2015,43(22):10893-10906
Upon infection of Escherichia coli by bacteriophage Qβ, the virus-encoded β-subunit recruits host translation elongation factors EF-Tu and EF-Ts and ribosomal protein S1 to form the Qβ replicase holoenzyme complex, which is responsible for amplifying the Qβ (+)-RNA genome. Here, we use X-ray crystallography, NMR spectroscopy, as well as sequence conservation, surface electrostatic potential and mutational analyses to decipher the roles of the β-subunit and the first two oligonucleotide-oligosaccharide-binding domains of S1 (OB1–2) in the recognition of Qβ (+)-RNA by the Qβ replicase complex. We show how three basic residues of the β subunit form a patch located adjacent to the OB2 domain, and use NMR spectroscopy to demonstrate for the first time that OB2 is able to interact with RNA. Neutralization of the basic residues by mutagenesis results in a loss of both the phage infectivity in vivo and the ability of Qβ replicase to amplify the genomic RNA in vitro. In contrast, replication of smaller replicable RNAs is not affected. Taken together, our data suggest that the β-subunit and protein S1 cooperatively bind the (+)-stranded Qβ genome during replication initiation and provide a foundation for understanding template discrimination during replication initiation. 相似文献
94.
Structural studies of the C‐terminal 19‐peptide of serum amyloid A and its Pro→Ala variants interacting with human cystatin C
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Martyna Maszota Natalia Karska Marta Spodzieja Jerzy Ciarkowski Aleksandra S. Koodziejczyk Sylwia Rodziewicz‐Motowido Paulina Czaplewska 《Journal of molecular recognition : JMR》2015,28(7):413-426
Serum amyloid A (SAA) is a multifunctional acute‐phase protein whose concentration in serum increases markedly following a number of chronic inflammatory and neoplastic diseases. Prolonged high SAA level may give rise to reactive systemic amyloid A (AA) amyloidosis, where the N‐terminal segment of SAA is deposited as amyloid fibrils. Besides, recently, well‐documented association of SAA with high‐density lipoprotein or glycosaminoglycans, in particular heparin/heparin sulfate (HS), and specific interaction between SAA and human cystatin C (hCC), the ubiquitous inhibitor of cysteine proteases, was proved. Using a combination of selective proteolytic excision and high‐resolution mass spectrometry, a hCC binding site in the SAA sequence was determined as SAA(86–104). The role of this SAA C‐terminal fragment as a ligand‐binding locus is still not clear. It was postulated important in native SAA folding and in pathogenesis of AA amyloidosis. In the search of conformational details of this SAA fragment, we did its structure and affinity studies, including its selected double/triple Pro→Ala variants. Our results clearly show that the SAA(86–104) 19‐peptide has rather unordered structure with bends in its C‐terminal part, which is consistent with the previous results relating to the whole protein. The results of affinity chromatography, fluorescent ELISA‐like test, CD and NMR studies point to an importance of proline residues on structure of SAA(86–104). Conformational details of SAA fragment, responsible for hCC binding, may help to understand the objective of hCC–SAA complex formation and its importance for pathogenesis of reactive amyloid A amyloidosis. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
95.
Terézia Horváthová Andrzej Antol Marcin Czarnoleski Paulina Kramarz Ulf Bauchinger Anna Maria Labecka Jan Koz?owski 《ZooKeys》2015,(515):67-79
According to the temperature-size rule (TSR), ectotherms developing under cold conditions experience slower growth as juveniles but reach a larger size at maturity. Whether temperature alone causes this phenomenon is unknown, but oxygen limitation can play a role in the temperature-size relationship. Oxygen may become limited under warm conditions when the resulting higher metabolism creates a greater demand for oxygen, especially in larger individuals. We examined the independent effects of oxygen concentration (10% and 22% O2) and temperature (15 °C and 22 °C) on duration of ontogenic development, which takes place within the maternal brood pouch (marsupium), and juvenile growth in the terrestrial isopod common rough woodlouse (Porcellio
scaber). Individuals inside the marsupium undergo the change from the aqueous to the gaseous environment. Under hypoxia, woodlice hatched from the marsupium sooner, but their subsequent growth was not affected by the level of oxygen. Marsupial development and juvenile growth were almost three times slower at low temperature, and marsupial development was longer in larger females but only in the cold treatment. These results show that temperature and oxygen are important ecological factors affecting developmental time and that the strength of the effect likely depends on the availability of oxygen in the environment. 相似文献
96.
David E Loyola Cristell Navarro Paulina Uribe Katherine García Claudia Mella Diego Díaz Natalia Valdes Jaime Martínez-Urtaza Romilio T Espejo 《BMC genomics》2015,16(1)
Background
New strains of Vibrio parahaemolyticus that cause diarrhea in humans by seafood ingestion periodically emerge through continuous evolution in the ocean. Influx and expansion in the Southern Chilean ocean of a highly clonal V. parahaemolyticus (serotype O3:K6) population from South East Asia caused one of the largest seafood-related diarrhea outbreaks in the world. Here, genomics analyses of isolates from this rapidly expanding clonal population offered an opportunity to observe the molecular evolutionary changes often obscured in more diverse populations.Results
Whole genome sequence comparison of eight independent isolates of this population from mussels or clinical cases (from different years) was performed. Differences of 1366 to 217,729 bp genome length and 13 to 164 bp single nucleotide variants (SNVs) were found. Most genomic differences corresponded to the presence of regions unique to only one or two isolates, and were probably acquired by horizontal gene transfer (HGT). Some DNA gain was chromosomal but most was in plasmids. One isolate had a large region (8,644 bp) missing, which was probably caused by excision of a prophage. Genome innovation by the presence of unique DNA, attributable to HGT from related bacteria, varied greatly among the isolates, with values of 1,366 (ten times the number of highest number of SNVs) to 217,729 (a thousand times more than the number of highest number of SNVs).Conclusions
The evolutionary forces (SNVs, HGT) acting on each isolate of the same population were found to differ to an extent that probably depended on the ecological scenario and life circumstances of each bacterium.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1385-8) contains supplementary material, which is available to authorized users. 相似文献97.
Richards EH Bradish H Dani MP Pietravalle S Lawson A 《Archives of insect biochemistry and physiology》2011,78(3):119-131
Although fungi are used to control a variety of insect pests, it is accepted that their usage could be increased if their efficacy was greater. The outcome of the interaction of a fungus and a pest insect may be influenced by a number of criteria, including the ability of the insect to mount effective immune responses against the pathogen. In view of this, we aimed to determine if a recombinant immunosuppressive wasp venom protein (rVPr1) can increase the susceptibility of larvae of the lepidopteran pest, Mamestra brassicae, to the fungal biological control agent, Beauveria bassiana. Bioassays indicated that when larvae were injected with 3.5 μl of rVPr1 and 100 B. bassiana conidia (combined injection assays), a significant reduction in survival of larvae occurred compared with each treatment on its own (P=0.006). Similar results were obtained when larvae were dipped in a solution containing 3 × 10(6) B. bassiana conidia per ml and then injected with 3.5 μl of rVPr1 2 days later (topical application assays), (P<0.001). These results indicate that rVPr1 can increase the efficacy of B. bassiana toward a lepidopteran pest, and are discussed within the context of insect immune responses and integrated pest management. 相似文献
98.
Georgieva D Greunke K Arni RK Betzel C 《Zeitschrift für Naturforschung. C, Journal of biosciences》2011,66(5-6):305-312
Api SI and Api SII are serine proteases of the honeybee venom containing allergenic determinants. Each protease consists of two structural modules: an N-terminal CUB (Api SI) or a clip domain (Api SII) and a C-terminal serine protease-like (SPL) domain. Both domains are connected with a linker peptide. The knowledge about the structure and function of Api SI and Api SII is limited mainly to their amino acid sequences. We constructed 3-D models of the two proteases using their amino acid sequences and crystallographic coordinates of related proteins. The models of the SPL domains were built using the structure of the prophenoloxidase-activating factor (PPAF)-II as a template. For modelling of the Api SI CUB domain the coordinates of porcine spermadhesin PSP-I were used. The models revealed the catalytic and substrate-binding sites and the negatively charged residue responsible for the trypsin-like activity. IgE-binding and antigenic sites in the two allergens were predicted using the models and programs based on the structure of known epitopes. Api SI and Api SII show structural and functional similarity to the members of the PPAF-II family. Most probably, they are part of the defence system of Apis mellifera. 相似文献
99.
Del Rio R Muñoz C Arias P Court FA Moya EA Iturriaga R 《American journal of physiology. Lung cellular and molecular physiology》2011,301(5):L702-L711
Chronic intermittent hypoxia (CIH), a characteristic of sleep obstructive apnea, enhances carotid body (CB) chemosensory responses to hypoxia, but its consequences on CB vascular area and VEGF expression are unknown. Accordingly, we studied the effect of CIH on CB volume, glomus cell numbers, blood vessel diameter and number, and VEGF immunoreactivity (VEGF-ir) in male Sprague-Dawley rats exposed to 5% O(2), 12 times/h for 8 h or sham condition for 21 days. We found that CIH did not modify the CB volume or the number of glomus cells but increased VEGF-ir and enlarged the vascular area by increasing the size of the blood vessels, whereas the number of the vessels was unchanged. Because oxidative stress plays an essential role in the CIH-induced carotid chemosensory potentiation, we tested whether antioxidant treatment with ascorbic acid may impede the vascular enlargement and the VEGF upregulation. Ascorbic acid, which prevents the CB chemosensory potentiation, failed to impede the vascular enlargement and the increased VEGF-ir. Thus present results suggest that the CB vascular enlargement induced by CIH is a direct effect of intermittent hypoxia and not secondary to the oxidative stress. Accordingly, the subsequent capillary changes may be secondary to the mechanisms involved in the neural chemosensory plasticity induced by intermittent hypoxia. 相似文献
100.
Skrzeszewska PJ Jong LN de Wolf FA Cohen Stuart MA van der Gucht J 《Biomacromolecules》2011,12(6):2285-2292
In this article we study shape-memory behavior of hydrogels, formed by biodegradable and biocompatible recombinant telechelic polypeptides, with collagen-like end blocks and a random coil-like middle block. The programmed shape of these hydrogels was achieved by chemical cross-linking of lysine residues present in the random coil. This led to soft networks, which can be stretched up to 200% and "pinned" in a temporary shape by lowering the temperature and allowing the collagen-like end blocks to assemble into physical nodes. The deformed shape of the hydrogel can be maintained, at room temperature, for several days, or relaxed within a few minutes upon heating to 50 °C or higher. The presented hydrogels could return to their programmed shape even after several thermomechanical cycles, indicating that they remember the programmed shape. The kinetics of shape recovery at different temperatures was studied in more detail and analyzed using a mechanical model composed of two springs and a dashpot. 相似文献