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931.
932.
George R. Young Jonathan P. Stoye George Kassiotis 《BioEssays : news and reviews in molecular, cellular and developmental biology》2013,35(9):794-803
A number of observations have led researchers to postulate that, despite being replication‐defective, human endogenous retroviruses (HERVs) may have retained the potential to cause or contribute to disease. However, mechanisms of HERV pathogenicity might differ substantially from those of modern infectious retroviruses or of the infectious precursors of HERVs. Therefore, novel pathways of HERV involvement in disease pathogenesis should be investigated. Recent technological advances in sequencing and bioinformatics are making this task increasingly feasible. The accumulating knowledge of HERV biology may also facilitate the definition and general acceptance of criteria that establish HERV pathogenicity. Here, we explore possible mechanisms whereby HERVs may cause disease and examine the evidence that either has been or should be obtained in order to decisively address the pathogenic potential of HERVs. 相似文献
933.
934.
George C. Nadăş Marian A. Taulescu Lidia Ciobanu Nicodim I. Fiţ Chirilă Flore Sorin Răpuntean Cosmina M. Bouari Cornel Catoi 《Mycopathologia》2013,175(3-4):221-230
Recent studies suggest that Candida albicans colonization is associated with several gastrointestinal inflammatory disorders and is also responsible for the delay in ulcer healing. No data are reported about the effects of C. albicans on the nonsteroidal anti-inflammatory drugs (NSAIDs)-induced necroinflammatory lesions. On the other hand, beneficial effects of NSAIDs regarding the colonization potential with C. albicans have been reported. Our aim was to investigate whether the association between NSAIDs and C. albicans could potentially induce necroinflammatory lesions in the guinea pigs gastric and enteral mucosa. Three interventional groups of 11 guinea pigs each were investigated after 5 days of receiving indomethacin, C. albicans or the association of both. C. albicans and necroinflammatory lesions were graded based on histological examinations. Statistical analysis used Mann–Whitney nonparametric test. NSAIDs did not significantly decrease C. albicans colonization grades on gastrointestinal mucosa. Administration of indomethacin subsequent to C. albicans determined significantly more severe necroinflammatory lesions compared to group that only received C. albicans. The association of NSAIDs and C. albicans did not cause significantly more severe degenerative or inflammatory lesions compared to the administration of only NSAIDs in this experimental model. Associations between NSAIDs and C. albicans caused significantly more severe necroinflammatory injuries than the lesions produced by C. albicans, without enhancing the mucosal injury or inflammation caused by NSAIDs. 相似文献
935.
Mercedes di Pasquo George W. Grader Peter Isaacson Paulo A. Souza Roberto Iannuzzi Enrique Díaz-Martínez 《Historical Biology》2013,25(7):868-897
This paper presents new data about Early Permian (Cisuralian) strata, palynostratigraphy and absolute dating from the Copacabana Formation in central Bolivia. Recent stratigraphic and palynologic data from marine and transitional rocks at Apillapampa refine the age of Cisuralian palynomorphs in South America. Twelve samples interbedded with five volcanic ashes (processed and productive) yielded 94 palynomorph species arranged in two informal palynoassemblages: the lower assemblage Vittatina costabilis corresponds to one sample near the base of the Copacabana Formation and the upper Lueckisporites virkkiae assemblage occurs in overlying marine and coal-bearing transitional intervals. Ages were also independently refined by a modern review of conodonts, fusulinids, along with those U–Pb radiometric ages (Isotope Dilution Thermal Ionization Mass Spectrometry [ID-TIMS] of zircon-bearing interbedded tuffs). These data suggest that the lower marine member of the Copacabana Formation at this location is Asselian and Sakmarian. Lueckisporites virkkiae is a key species of palynomorph utilised in South American and global Permian biostratigraphic reconstructions. Hence, a thorough global comparison of these palynofloras and correlations is addressed in this contribution, considering first appearances of mainly cosmopolitan diagnostic taxa. Correlations are established with many similar Permian palynofloras, some also constrained with radiometric data, in South America (Brazil, Uruguay and Argentina) and elsewhere. 相似文献
936.
The following new genus and seven new species of Cossonine weevils (Curculionidae: Cossoninae) are described from Dominican amber: Acamptus exilipes Poinar and Legalov, n. sp. (similar to A. rigidus), Caulophilus camptus Poinar and Legalov, n. sp. (similar to C. bennetti), Caulophilus elongatus Poinar and Legalov, n. sp. (similar to C. swensoni), Caulophilus ruidipunctus Poinar and Legalov, n. sp., Dryotribus pedanus Poinar and Legalov, n. sp. (similar to D. amplioculus), Ogygius obrieni Poinar and Legalov, n. gen., n. sp. (similar to the genus Apotrepus), and Stenotrupis pumilis Poinar and Legalov, n. sp. (similar to S. breviscapus). A key to the Dominican amber species of the genus Caulophilus is provided. Based on the extant weevil fauna, it appears that the Hispaniolan Cossonine were more diverse in the Tertiary than at present. http://zoobank.org/urn:lsid:zoobank.org:pub:14D1CFC0-4967-4D22-888B-0DE3E157D6BD 相似文献
937.
A new species of Dryophthorus and two new species of Stenommatus (Coleoptera: Dryophthoridae) are described from Dominican amber. Dryophthorus microtremus n. sp. is characterised by monochrome dorsal scales, nearly parallel sides of the pronotum, wide elytral intervals and the elytral apex only slightly narrowed. Stenommatus tanyrhinus n. sp. is characterised by an elongate rostrum 4.5 times as long as wide in the middle. S. leptorhinus is characterised by small body size, a thin rostrum 3.0 times as long as wide in the middle, wide striae and a narrow prosternal process. This brings the total number of species of Dryophthorini in Dominican amber to five, which is more than half the number of extant species.http://www.zoobank.org/urn:lsid:zoobank.org:pub:4329D0DA-57BD-4CEA-9464-ABD5D1577FC9 相似文献
938.
Disulfide bonds formed by the oxidation of cysteine residues in proteins are the major form of intra- and inter-molecular covalent linkages in the polypeptide chain. To better understand the conformational energetics of this linkage, we have used the MP2(full)/6-31G(d) method to generate a full potential energy surface (PES) for the torsion of the model compound diethyl disulfide (DEDS) around its three critical dihedral angles (χ2, χ3, χ2′). The use of ten degree increments for each of the parameters resulted in a continuous, fine-grained surface. This allowed us to accurately predict the relative stabilities of disulfide bonds in high resolution structures from the Protein Data Bank. The MP2(full) surface showed significant qualitative differences from the PES calculated using the Amber force field. In particular, a different ordering was seen for the relative energies of the local minima. Thus, Amber energies are not reliable for comparison of the relative stabilities of disulfide bonds. Surprisingly, the surface did not show a minimum associated with χ2~ ? 60°, χ3~90, χ2′~ ? 60°. This is due to steric interference between Hα atoms. Despite this, significant populations of disulfides were found to adopt this conformation. In most cases this conformation is associated with an unusual secondary structure motif, the cross-strand disulfide. The relative instability of cross-strand disulfides is of great interest, as they have the potential to act as functional switches in redox processes. 相似文献
939.
The structure of N i -( N '-Sulfodiaminophosphinyl)- l -ornithine (PSOrn) in complex with the enzyme ornithine transcarbamoylase (OTCase) was recently characterised by Langley et al. [D.B. Langley, M.D. Templeton, B.A. Fields, R.E. Mitchell and C.A. Collyer, J. Biol. Chem., 275 (2000) 20012] using X-ray diffraction techniques. In this work, the interaction of PSOrn with the arginine residues of OTCase is modelled using density functional theory, with an emphasis on characterising the mechanism of binding between PSOrn, an inhibitor, and the enzyme. For the purposes of this study, the interaction of PSO, an analogue of PSOrn (obtained by replacing a (CH 2 ) 3 CH( CO 2 m )( NH 3 + ) side chain by methyl) with one and two arginine (Arg) molecules are investigated. The PSO > (Arg) 2 trimer is found to be strongly bound, by ~171 kJ mol m 1 , due to the presence of four hydrogen bonds in addition to a large ionic interaction between a dinegative PSO 2 m and protonated arginines. The computed geometry is consistent with the X-ray structure and the large binding energy is consistent with the observation that PSOrn is a powerful inhibitor. Furthermore, in agreement with the proposals of Langley et al. , the most stable bound form of PSO is found to be an imino type tautomer. The population analyses that were carried out on PSO suggest that PN, PO, SN and SO bonds, as in a range of other systems, are generally either single or semipolar bonds. 相似文献
940.
From “Haus Tambaran” to Church: Continuity and Change in Contemporary Papua New Guinean Architecture
George Jell Sabine Jell-Bahlsen 《Visual Anthropology: Published in cooperation with the Commission on Visual Anthropology》2013,26(5):407-437
ABSTRACT This article examines contemporary Papua New Guinean architecture created in the oscillation between Melanesian culture and Western impact. Some of the country's indigenous buildings are truly remarkable, especially the prestigious structures known as “Haus Tambaran” in the Sepik River area which have lent inspiration to many outstanding samples of contemporary Papua New Guinean design. We have studied both the indigenous and contemporary architecture of the Sepik region in the field and in additional research in collaboration with the late Professor Wallace Ruff and are comparing and contrasting contemporary architectural design with indigenous buildings. Here, we focus on a church at Ambunti, East Sepik Province. There is no electricity available on the site to facilitate climate control. Moreover, this contemporary building serves Western political, social, religious and educational functions. At the same time, the church incorporates aspects of the country's architectural heritage, including aesthetics as well as site-design and design with climate. Our comparison contrasts the modern building's functions, aesthetics, and design solutions with the area's indigenous local equivalent, the Haus Tambaran, and reveals elements borrowed, left aside, or altered in the process of adaptation. Issues discussed here include historic precedent, aesthetics, ownership, gender, and other social issues, as well as design and construction. Formal aspects, their meanings and functions, as well as environmental considerations and design solutions are borrowed, translated, or transformed, recalling but also differing from “Green Architecture,” to serve contemporary Western needs. 相似文献