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1.

Copper(I)-catalyzed 5-endo-dig cyclizations of 5-(alkyn-1-yl)uracil derivatives had given poor yields of substituted furo[2 Robins, M. J. and Barr, P. J. 1983. Nucleic acid related compounds. 39. Efficient conversion of 5-iodo to 5-alkynyl and derived 5-substituted uracil bases and nucleosides. J. Org. Chem, 48: 18541862. [CSA][CROSSREF][Crossref], [Web of Science ®] [Google Scholar], 3 De Clercq, E., Descamps, J., Balzarini, J., Giziewicz, J., Barr, P. J. and Robins, M. J. 1983. Nucleic acid related compounds. 40. Synthesis and biological activities of 5-alkynyluracil nucleosides. J. Med. Chem, 26: 661666. [PUBMED][INFOTRIEVE][CSA][CROSSREF][Crossref], [PubMed], [Web of Science ®] [Google Scholar]]pyrimidin-2-ones unless the uracil ring was substituted at N1 with alkyl or glycosyl groups. This limited flexibility for the synthesis of analogues with varied substituents at N3 and/or C6 of the furo[2 Robins, M. J. and Barr, P. J. 1983. Nucleic acid related compounds. 39. Efficient conversion of 5-iodo to 5-alkynyl and derived 5-substituted uracil bases and nucleosides. J. Org. Chem, 48: 18541862. [CSA][CROSSREF][Crossref], [Web of Science ®] [Google Scholar], 3 De Clercq, E., Descamps, J., Balzarini, J., Giziewicz, J., Barr, P. J. and Robins, M. J. 1983. Nucleic acid related compounds. 40. Synthesis and biological activities of 5-alkynyluracil nucleosides. J. Med. Chem, 26: 661666. [PUBMED][INFOTRIEVE][CSA][CROSSREF][Crossref], [PubMed], [Web of Science ®] [Google Scholar]]pyrimidin-2-one core has been overcome with 5-(3-hydroxyalkyn-1-yl)uracil compounds with no substituent at N1. Manipulation of the side-chain hydroxyl group gives access to additional furo[2,3-d]pyrimidin-2-one analogues.  相似文献   

2.
We investigated the morphology, morphogenesis and small subunit rRNA gene-based phylogeny of three marine urostylids, Uncinata gigantea Bullington, 1940 Bullington, W. E. (1940). Some ciliates from Tortugas. Papers from the Tortugas Laboratory, 32, 179221. [Google Scholar], Holosticha heterofoissneri Hu & Song, 2001 Hu, X., & Song, W. (2001). Morphology and morphogenesis of Holosticha heterofoissneri n. sp. from the Yellow Sea, China (Ciliophora, Hypotrichida). Hydrobiologia, 448, 171179. doi:10.1023/A:1017553406031.[Crossref], [Web of Science ®] [Google Scholar], and Holosticha cf. heterofoissneri. The dorsal morphogenesis of Uncinata gigantea shows de novo formation of two groups of anlagen near the marginal rows. Holosticha cf. heterofoissneri demonstrates fragmentation of the first dorsal kinety anlage as in Holosticha heterofoissneri. Our population of H. heterofoissneri corresponds well with previously described populations in terms of its general morphology and ciliary pattern. Uncinata gigantea can be recognized by its large and highly contractile body, yellowish to brownish cell colour, two types of cortical granules, and 20–30 transversely oriented and densely arranged cirri in the left marginal row, which often overlie the buccal vertex. Based on the new data, especially infraciliature, the genus Uncinata is here redefined. Both the morphology and phylogenetic analyses suggest that the genus Uncinata should be classified within the family Urostylidae. In addition, both morphological and morphogenetic data suggest that Holosticha bradburyae Gong et al., 2001 Gong, J., Song, W., Hu, X., Ma, H., & Zhu, M. (2001). Morphology and infraciliature of Holosticha bradburyae n. sp. (Ciliophora, Hypotrichida) from the Yellow Sea, China. Hydrobiologia, 464, 6369. doi:10.1023/A:1013901621439.[Crossref], [Web of Science ®] [Google Scholar] should be transferred to Uncinata as U. bradburyae (Gong et al., 2001 Gong, J., Song, W., Hu, X., Ma, H., & Zhu, M. (2001). Morphology and infraciliature of Holosticha bradburyae n. sp. (Ciliophora, Hypotrichida) from the Yellow Sea, China. Hydrobiologia, 464, 6369. doi:10.1023/A:1013901621439.[Crossref], [Web of Science ®] [Google Scholar]) comb. nov., due to its possession of a characteristically prominent beak-like, leftwards curved projection and the developmental mode of the dorsal kineties. This assignment is supported by the phylogenetic analyses, which placed Uncinata gigantea in a clade with U. bradburyae (Gong et al., 2001 Gong, J., Song, W., Hu, X., Ma, H., & Zhu, M. (2001). Morphology and infraciliature of Holosticha bradburyae n. sp. (Ciliophora, Hypotrichida) from the Yellow Sea, China. Hydrobiologia, 464, 6369. doi:10.1023/A:1013901621439.[Crossref], [Web of Science ®] [Google Scholar]) comb. nov., and revealed only 1.13% (19 bp) difference in their SSU-rDNA gene sequence.  相似文献   

3.
Ilya V. Buynevich 《Ichnos》2013,20(4):189-191
Recognition and sampling of traces in unconsolidated sands present a major challenge for ichnologists. This can be partially remedied through the application of high-resolution geophysical techniques, such as ground-penetrating radar (GPR or georadar), which uses electromagnetic impulse for continuous imaging of shallow subsurface. It addition to geological applications, GPR imaging has been used in several studies focused on animal traces as related to conservation of endangered fossorial species (Kinlaw et al., 2007 Kinlaw, A. E., Conyers, L. B. and Zajac, W. 2007. Use of ground penetrating radar to image burrows of the gopher tortoise (Gopherus polyphemus). Herpetological Review, 38: 5056.  [Google Scholar]; Martin et al., 2011 Martin, A. J., Skaggs, S. A., Vance, R. K. and Greco, V. 2011. Ground-penetrating radar investigation of gopher-tortoise burrows: Refining the characterization of modern vertebrate burrows and associated commensal traces. Geological Society of America Abstracts with Programs, 43: 381 [Google Scholar]), slope and levee stability (Nichol et al., 2003 Nichol, D., Lenham, J. W. and Reynolds, J. M. 2003. Application of ground-penetrating radar to investigate the effects of badger setts on slope stability at St. Asaph Bypass, North Wales. Quarterly Journal of Engineering Geology and Hydrogeology, 36: 143153.  [Google Scholar]; Di Prinzio et al., 2010 Di Prinzio, M, Bittelli, M., Castellarin, A. and Pisa, P. R. 2010. Application of GPR to the monitoring of river embankments. Journal of Applied Geophysics, 7: 5361.  [Google Scholar]), and mapping of fossil tracks (Matthews et al., 2006 Matthews, N. A., Noble, T. A. and Breithaupt, B. H. 2006. “The application of photogrammetry, remote sensing and geographic information systems (GIS) to fossil resource management”. In Fossils from Federal Lands, Edited by: Lucas, S. G., Spielmann, J. A., Hester, P. M., Kenworthy, J. P. and Santucci, V. L. Vol. 34, 119131. New Mexico Museum of Natural History and Science Bulletin.  [Google Scholar]; Aucoin and Hasbargen, 2010 Aucoin, C. D. and Hasbargen, L. 2010. Using GPR, GPS and close-range photography to map and characterize dinosaur tracks in the Connecticut River valley. Geological Society of America Abstracts with Programs, 42: 276 [Google Scholar]) and tracking surfaces (Webb, 2007 Webb, S. 2007. Further research of the Willandra Lakes fossil footprint site, southeastern Australia. Journal of Human Evolution, 52: 711715. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]). Few efforts have been dedicated specifically to characterizing burrow and track characteristics (Stott, 1996 Stott, P. 1996. Ground-penetrating radar: a technique for investigating the burrow structure of fossorial vertebrates. Wildlife Research, 22: 519530.  [Google Scholar]; Sensors & Software Inc., 2010 [compilation on geophysical projects related to animal burrows]; Buynevich and Hasiotis, 2011; Buynevich et al., 2011; Martin et al., 2011) and most of the above studies are published in journals not routinely accessed by ichnologists.  相似文献   

4.
In Disney/Pixar's phenomenally popular animated film Finding Nemo (Stanton, 2003 Stanton, A. Writer/Director. 2003. Finding Nemo [Motion picture], United States: Pixar Animation Studios.  [Google Scholar]), one of the central themes of fish welfare was highlighted when the moorish idol, Gill, commented, “Fish aren't meant to be kept in a box, kid. It does things to you.” The notion that fish might have the capacity to suffer in captivity (Chandroo, Duncan, & Moccia, 2004a Chandroo, K. P., Duncan, I. J. H and Moccia, R. D. 2004a. Can fish suffer?: Perspectives on sentience, pain, fear and stress. Applied Animal Behaviour Science, 86: 225250. [Crossref], [Web of Science ®] [Google Scholar], 2004b Chandroo, K. P., Duncan, I. J. H and Moccia, R. D. 2004b. An evaluation of current perspectives on consciousness and pain in fish. Fish and Fisheries, 5: 281295. [Crossref], [Web of Science ®] [Google Scholar]) links to the larger question of sentiency, which remains a fundamental tenet when justifying concerns for nonhuman animal welfare (Dawkins, 2006 Dawkins, M. S. 2006. Through animal eyes: What behaviour tells us. Applied Animal Behaviour Science, 100: 410. [Crossref], [Web of Science ®] [Google Scholar]; Huntingford et al., 2006 Huntingford, F. A., Adams, C., Braithwaite, V. A., Kadri, S., Pottinger, T. G.Sandoe, P. 2006. Review paper: Current issues in fish welfare. Journal of Fish Biology, 68: 332372. [Crossref], [Web of Science ®] [Google Scholar]). Although terrestrial nonhuman-animal welfare has been discussed and explored for many years, the development of aquatic animal welfare concepts and approaches remains relatively new and beyond public awareness (Braastad, Damsgård, & Juell, 2006; Broom, 2007 Broom, D. M. 2007. Cognitive ability and sentience: Which aquatic animals should be protected?. Disease of Aquatic Organisms, 75: 99108. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]; Farmed Animal Welfare Council, 1996; Fisheries Society of the British Isles, 2002; Håstein, Scarfe, & Lund, 2005; Iwama, 2007 Iwama, G. K. 2007. The welfare of fish. Diseases of Aquatic Organisms, 75: 155158. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]; Schreck, 1981 Schreck, C. B. 1981. “Stress and compensation in teleostean fishes: Response to social and physical factors”. In Stress and fish, Edited by: Pickering, A. D. 295321. London: Academic.  [Google Scholar]).  相似文献   

5.
6.
The natural remobilization of an initially static mixed dense non-aqueous phase liquid (DNAPL) pool due to dissolution was demonstrated by (Roy et al. 2002 Roy, J. W., Smith, J. E. and Gillham, R. W. 2002. Natural remobilization of multicomponent DNAPL pools due to dissolution. J. Contam. Hydrol., 59: 163186. [Crossref], [PubMed], [Web of Science ®] [Google Scholar], 2004 Roy, J. W., Smith, J. E. and Gillham, R. W. 2004. Laboratory evidence of natural remobilization of multicomponent DNAPL pools due to dissolution. J. Contam. Hydrol., 74: 145161. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]) using a compositional mathematical model and laboratory experiments with open pools over a porous medium. The purposes of this study were to: a) demonstrate natural remobilization for a pool within porous media (as opposed to an open pool); and b) analyze the capillary effects associated with residual formation, a changing saturation profile, hysteresis, and aging, as these processes may reduce the potential for natural remobilization of pools in porous media. DNAPL pools comprised of tetrachloroethene and benzene were created within a zone of larger glass beads overlying smaller glass beads, in a water-saturated 2-D flow cell. In one case, remobilization occurred in the form of a DNAPL finger, after 56 days of flushing. In another case, no remobilization had occurred after 64 days of flushing, though the density increased by 430 kg m ?3 and remobilization was predicted by the compositional model. Comparison of observations with model predictions suggest that contact angle hysteresis, related to an observed change in wettability, was the most significant contributing factor causing overprediction of the potential for natural remobilization.  相似文献   

7.
An automated, iterative approach to finding the lowest energy, ionic diffusion paths through a periodic structure has been developed within our new code (written in FORTRAN 77 and named Bubble). The approach is quite general in that it can be applied to find, at a chosen temperature, the accessible (ergodic) regions of a hyper-surface, which is defined across a uniform grid [1 Schön, J.C., Putz, H. and Jansen, M. 1996. Studying the energy hypersurface of continuous system—The threshold algorithm. J. Phys.-Conden. Matt., 8: 143[Crossref] [Google Scholar]]. We describe both our implementation within the Bubble code and its application to locating the approximate transition states for Mg interstitial diffusion in forsterite, which can then be refined using standard transition state searching [2 Banerjee, A., Adams, N., Simons, J. and Shepard, R. 1985. Search for stationary points on surfaces. J. Phys. Chem., 89: 52[Crossref], [Web of Science ®] [Google Scholar]].  相似文献   

8.
The Divakar-Reese procedure has been successfully applied for transforming 7-oxo-isothiazolo[4,5-d]pyrimidine C-nucleosides (4a,b, 5a,b, 6a) via 1,2,4-triazol-1-yl intermediates (7a,b, 8a,b) into various 7-substituted C-nucle- osides 15a,b, 16a,b, 17a, 18a, 19a,b, 20a,b; their subsequent deprotection provides novel types of unusual C-glycosides 22b, 23a, 24a,b, 25b, 26b.

C-Nucleosides, possessing on its heterocyclic base other than naturally occuring oxo- or amino substituents, are important model compounds for biological or medicinal studies [2a] Hanessian, S. and Pernet, A. G. 1976. Adv. Carbohydr. Chem. Biochem., 32: 111188. cf. [Google Scholar], [2b] Mizuno, Y. 1986. The Organic Chemistry of Nucleic Acids Amsterdam: Elsevier.  [Google Scholar], [2c] Huryn, D. M. and Okabe, M. 1992. Chem. Rev., 92: 17451768. [Crossref], [Web of Science ®] [Google Scholar], [2d] Häbich, D. 1991. Chem. in uns. Zeit, 25: 295307.  [Google Scholar], [2e] Uhlmann, E. and Peyman, A. 1990. Chem. Rev., 90: 543584. [Crossref], [Web of Science ®] [Google Scholar], [2f] Thuong, N. T. and Helene, C. 1993. Angew. Chem., 105: 697723. [Crossref] [Google Scholar], [2g] 1993. Angew. Chem. Int. Ed. Engl., 33: 666690.  [Google Scholar], [2h] Yarchoan, R., Mitsuya, H., Zhomas, R. V., Pluda, J. M., Hartman, N. R., Perno, C. F., Marczyk, K. S., Allain, J. P., Johns, D. G. and Broder, S. 1989. Science, 245: 412414. [Crossref], [PubMed], [Web of Science ®] [Google Scholar], [2i] Tanaka, H., Baba, M., Hayakawa, H., Sakamaki, T., Miyasaka, T., Ubasawa, M., Takashima, H., Sekiya, E., Nitta, I., Shigeta, S., Walker, R. T., Balzarini, J. and De Clerq, E. 1991. J. Med. Chem., 34: 349357. [Crossref], [PubMed], [Web of Science ®] [Google Scholar] [3a] Koyama, G., Maeda, K., Umezawa, H. and Iitaka, Y. 1966. Tetrahedron Lett., : 597602. Some C-glycosides with antibiotic, antiviral (HIV), and anticancer activities [Google Scholar], [3b] Hori, M., Wakashiro, T., Ito, E., Sawa, T., Takeuchi, T. and Umezawa, H. J. 1968. J. Antibiot., 21A: 264270. [Chem. Abstr. 1968, 69, 11356j] [Google Scholar], [3c] Farkas, J. and ?orm. 1972. F. Collect. Czech. Chem. Commun., 37: 27982803.  [Google Scholar], [3d] Acton, E. M., Ryan, K. J., Henry, D. W. and Goodman, L. 1971. J. Chem. Soc., Chem. Commun., : 986988.  [Google Scholar], [3e] Nakagawa, Y., Kano, H., Tsukuda, Y. and Koyama, H. 1967. Tetrahedron Lett., : 41054109.  [Google Scholar], [3f] Inoue, I. and Kuwaijama, I. 1980. J. Chem. Soc., Chem. Commun., : 251253.  [Google Scholar], [3g] Buchanan, J. G., Stobie, A. and Wightman, R. H. 1980. ibid., : 916917. [Crossref] [Google Scholar], [3h] Hildebrand, S. and Leumann, C. 1996. Angew. Chem., 108: 21002102. Angew. Chem. Int. Ed. Engl. 1996, 35, 1968–1970 [Google Scholar]. We want to report on the synthesis of novel 7-substituted isothiazolo = [4,5-d]pyrimidine C-nucleosides. As we could show in previous papers [1] Wamhoff, H., Berressem, R. and Nieger, M. 1994. J. Org. Chem., 59: 19121917. Part 2 [Google Scholar], [4] Wamhoff, H., Berressem, R. and Nieger. 1993. M. J. Org. Chem., 58: 51815185.  [Google Scholar], there exists a simple approach to the protected C-glycosides 46.

  相似文献   

9.
We address several conjectures raised in Cantrell et al. [Evolution of dispersal and ideal free distribution, Math. Biosci. Eng. 7 (2010), pp. 17–36 [9 Cantrell, R. S., Cosner, C. and Lou, Y. 2010. Evolution of dispersal and ideal free distribution. Math. Biosci. Eng., 7: 1736. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]]] concerning the dynamics of a diffusion–advection–competition model for two competing species. A conditional dispersal strategy, which results in the ideal free distribution of a single population at equilibrium, was found in Cantrell et al. [9 Cantrell, R. S., Cosner, C. and Lou, Y. 2010. Evolution of dispersal and ideal free distribution. Math. Biosci. Eng., 7: 1736. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]]. It was shown in [9 Cantrell, R. S., Cosner, C. and Lou, Y. 2010. Evolution of dispersal and ideal free distribution. Math. Biosci. Eng., 7: 1736. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]] that this special dispersal strategy is a local evolutionarily stable strategy (ESS) when the random diffusion rates of the two species are equal, and here we show that it is a global ESS for arbitrary random diffusion rates. The conditions in [9 Cantrell, R. S., Cosner, C. and Lou, Y. 2010. Evolution of dispersal and ideal free distribution. Math. Biosci. Eng., 7: 1736. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]] for the coexistence of two species are substantially improved. Finally, we show that this special dispersal strategy is not globally convergent stable for certain resource functions, in contrast with the result from [9 Cantrell, R. S., Cosner, C. and Lou, Y. 2010. Evolution of dispersal and ideal free distribution. Math. Biosci. Eng., 7: 1736. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]], which roughly says that this dispersal strategy is globally convergent stable for any monotone resource function.  相似文献   

10.
A toxicological approach was taken to determine the heavy metal binding capacity of soils. A soil heavy metal binding capacity (SHMBC) methodology was developed and was based on the use of the MetPLATE TM toxicity test kit, a bioassay that is specific for heavy metal toxicity. SHMBC test is based on the heavy metal binding capacity (HMBC) concept that has been considered in the assessment of the metal binding capacity of surface waters (Huang et al., 1999 Huang, F., Bitton, G. and Kong, I.-C. 1999. Determination of the heavy metal binding capacity of aquatic samples using MetPLATE?: a preliminary study. Sci. Total Environ, 234: 139145.  [Google Scholar]) and solid wastes landfill leachates (Ward et al., 2005 Ward, M., Bitton, G. and Townsend, T. 2005. Heavy metal binding capacity (HMBC) of municipal solid waste landfill leachates. Chemosphere, 60: 206215. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]). SHMBC is the ratio of the EC 50 of an added metal in a soil sample divided by the EC 50 of a metal in a reference soil (clean Ottawa sand). A higher SHMBC value indicates higher metal binding to soil and lower bioavailability and potential toxicity to the test bacteria.

Five soils (two sandy soils, two organic soils and a clay soil) were used to determine their binding capacity towards Cu, Zn, and Hg, using the developed SHMBC test. The test measured the ability of the solids to reduce metal bioavailability and toxicity. SHMBC was highest for the clay soil and lowest for the sandy soils. The potential application of this relatively rapid (a few hours) test to predict metal toxicity to terrestrial plants is discussed.  相似文献   


11.
《Fly》2013,7(4):155-159
ABSTRACT

Animals have modular cis-regulatory regions in their genomes, and expression of a single gene is often regulated by multiple enhancers residing in such a region. In the laboratory, and also in natural populations, loss of an enhancer can result in a loss of gene expression. Although only a few examples have been well characterized to date, some studies have suggested that an evolutionary gain of a new enhancer function can establish a new gene expression domain. Our recent study showed that Drosophila guttifera has more enhancers and additional expression domains of the wingless gene during the pupal stage, compared to D. melanogaster, and that these new features appear to have evolved in the ancestral lineage leading to D. guttifera.1 Koshikawa S, Giorgianni MW, Vaccaro K, Kassner VA, Yoder JH, Werner T, Carroll SB. Gain of cis-regulatory activities underlies novel domains of wingless gene expression in Drosophila. Proc Natl Acad Sci USA 2015; 112:7524-9; PMID:26034272; http://dx.doi.org/10.1073/pnas.1509022112[Crossref], [PubMed], [Web of Science ®] [Google Scholar] Gain of a new expression domain of a developmental regulatory gene (toolkit gene), such as wingless, can cause co-option of the expression of its downstream genes to the new domain, resulting in duplication of a preexisting structure at this new body position. Recently, with the advancement of evo-devo studies, we have learned that the developmental regulatory systems are strikingly similar across various animal taxa, in spite of the great diversity of the animals' morphology. Even behind “new” traits, co-options of essential developmental genes from known systems are very common. We previously provided concrete evidence of gains of enhancer activities of a developmental regulatory gene underlying gains of new traits.1 Koshikawa S, Giorgianni MW, Vaccaro K, Kassner VA, Yoder JH, Werner T, Carroll SB. Gain of cis-regulatory activities underlies novel domains of wingless gene expression in Drosophila. Proc Natl Acad Sci USA 2015; 112:7524-9; PMID:26034272; http://dx.doi.org/10.1073/pnas.1509022112[Crossref], [PubMed], [Web of Science ®] [Google Scholar] Broad occurrence of this scenario is testable and should be validated in the future.  相似文献   

12.
This paper considers the local, field-scale sustainability of a productive industrial maize agrosystem that has replaced a fertile grassland ecosystem.

Using the revised thermodynamic approach of Svirezhev (1998 Svirezhev, Y. M. 1998. “Thermodynamic orientors: How to use Thermodynamic concepts in ecology”. In Eco Targets, Goal Functions, and Orientors, 102122. Berlin: Springer Verlag. [Crossref] [Google Scholar], 2000 Svirezhev, Y. M. 2000. Thermodynamics and ecology. Ecological Modelling, 132: 1122. [Crossref], [Web of Science ®] [Google Scholar]) and Steinborn and Svirezhev (2000) Steinborn, W. and Svirezhev, Y. M. 2000. Entropy as an indicator of sustainability in agro-ecosystems: North Germany case study. Ecol. Mode., 133: 247257. [Crossref], [Web of Science ®] [Google Scholar], it is shown that currently this agrosystem is unsustainable in the U.S., with or without tilling the soil. The calculated average erosion rates of soil necessary to dissipate the entropy produced by U.S. maize agriculture, 23–45 t ha?1 yr?1, are bounded from above by an experimental estimate of mean soil erosion by conventional agriculture worldwide, 47 t ha?1 yr?1, (Montgomery, 2007 Montgomery, D. R. 2007. Soil erosion and agricultural sustainability. PNAS, 104(33): 1326813272. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]). Between 1982 and 1997, US agriculture caused an estimated 7–23 t ha?1 yr?1 of average erosion with the mean of 15 t ha?1 yr?1 (USDA-NRCS Database). The lower mean erosion rate of no till agriculture, 1.5 t ha?1 yr?1 (Montgomery, 2007 Montgomery, D. R. 2007. Soil erosion and agricultural sustainability. PNAS, 104(33): 1326813272. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]), necessitates the elimination of weeds and pests with field chemicals—with the ensuing chemical and biological soil degradation, and chemical runoff—to dissipate the produced entropy. The increased use of field chemicals that replace tillers is equivalent to the killing or injuring of up to 300 kg ha?1 yr?1 of soil flora and fauna. Additional soil degradation, not calculated here, occurs by acidification, buildup of insoluble metal compounds, and buildup of toxic residues from field chemicals. The degree of unsustainability of an average U.S. maize field is high, requiring 6–13 times more energy to reverse soil erosion and degradation, etc., than the direct energy inputs to maize agriculture. This additional energy, if spent, would not increase maize yields. The calculated “critical yield” of “organic” maize agriculture that does not use field chemicals and fossil fuels is only 30 percent lower than the average maize yield of 8.7 tons per hectare (~140 bu/acre) assumed here. This critical yield would not likely be achieved and sustained by large monocultures, but might be achieved by more balanced organic polycultures (Baum et al., 2008 Baum, A. W., Patzek, T. W., Bender, M., Renich, S. and Jackson, W. 2008. The Visible, Sustainable Farm: A Comprehensive Energy Analysis of a Midwestern Farm 134. Posted at petroleum.berkeley.edu/papers/Biofuels/SSF?Report3-051408.pdf [Google Scholar]).  相似文献   


13.
Localized mRNA translation is a widespread mechanism for targeting protein synthesis, important for cell fate, motility and pathogenesis. In Drosophila, the spatiotemporal control of gurken/TGF-α mRNA translation is required for establishing the embryonic body axes. A number of recent studies have highlighted key aspects of the mechanism of gurken mRNA translational control at the dorsoanterior corner of the mid-stage oocyte. Orb/CPEB and Wispy/GLD-2 are required for polyadenylation of gurken mRNA, but unlocalized gurken mRNA in the oocyte is not fully polyadenylated.1 Norvell A, Wong J, Randolph K, Thompson L. Wispy and Orb cooperate in the cytoplasmic polyadenylation of localized gurken mRNA. Dev Dyn Off Publ Am Assoc Anat 2015; 244:1276-1285. [Google Scholar] At the dorsoanterior corner, Orb and gurken mRNA have been shown to be enriched at the edge of Processing bodies, where translation occurs.2 Weil TT, Parton RM, Herpers B, Soetaert J, Veenendaal T, Xanthakis D, Dobbie IM, Halstead JM, Hayashi R, Rabouille C, et al. Drosophila patterning is established by differential association of mRNAs with P bodies. Nat Cell Biol 2012; 14:1305-1313; PMID:23178881; http://dx.doi.org/10.1038/ncb2627[Crossref], [PubMed], [Web of Science ®] [Google Scholar] Over-expression of Orb in the adjacent nurse cells, where gurken mRNA is transcribed, is sufficient to cause mis-expression of Gurken protein.3 Davidson A, Parton RM, Rabouille C, Weil TT, Davis I. Localized translation of gurken/TGF-α mRNA during axis specification is controlled by access to Orb/CPEB on processing bodies. Cell Rep 2016; 14:2451-2462; PMID:26947065; http://dx.doi.org/10.1016/j.celrep.2016.02.038[Crossref], [PubMed], [Web of Science ®] [Google Scholar] In orb mutant egg chambers, reducing the activity of CK2, a Serine/Threonine protein kinase, enhances the ventralized phenotype, consistent with perturbation of gurken translation.4 Wong LC, Costa A, McLeod I, Sarkeshik A, Yates J 3rd, Kyin S, Perlman D, Schedl P, et al. The functioning of the drosophila CPEB protein Orb is regulated by phosphorylation and requires casein kinase 2 activity. PLoS One 2011; 6:e24355; PMID:21949709; http://dx.doi.org/10.1371/journal.pone.0024355[Crossref], [PubMed], [Web of Science ®] [Google Scholar] Here we show that sites phosphorylated by CK2 overlap with active Orb and with Gurken protein expression. Together with our new findings we consolidate the literature into a working model for gurken mRNA translational control and review the role of kinases, cell cycle factors and polyadenylation machinery highlighting a multitude of conserved factors and mechanisms in the Drosophila egg chamber.  相似文献   

14.
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the selective death of motor neurons leading to paralysis and death between 3–5?years of diagnosis. Through whole genome association studies, several single nucleotide polymorphisms (SNPs) encoding missense mutations in angiogenin (ANG) protein have been identified as one of the primary factors causing ALS. Structural studies of ANG show that catalytic triad comprising His13, Lys40, and His114 residues imparts ribonucleolytic activity while nuclear localization signal residues 31RRR33 are responsible for nuclear translocation activity. Loss of either ribonucleolytic activity or nuclear translocation activity or both of these functions due to mutations cause ALS. However, the mechanisms of loss-of-functions of ANG mutants are not completely understood. Here, we present a cohesive and comprehensive picture of functional loss mechanisms of all known ALS-associated ANG mutants by extensive molecular dynamics (MD) simulations (Padhi, Kumar, Vasaikar, Jayaram, & Gomes, 2012 Padhi, A. K., Kumar, H., Vasaikar, S. V., Jayaram, B. and Gomes, J. 2012. Mechanisms of loss of functions of human angiogenin variants implicated in amyotrophic lateral sclerosis. PLoS One, 7(2): e32479[PubMed] [Google Scholar]; AK, 2013 Padhi, A.K., Jayaram, B., & Gomes, J. (accepted for publication). Prediction of functional loss of human angiogenin mutants associated with ALS by molecular dynamics simulations. Scientific Reports (NPG).  [Google Scholar]). Our studies show that conformational switching of catalytic residue His114 is responsible for the loss of ribonucleolytic activity while reduction in solvent-accessible surface area (SASA) of 31RRR33 as a result of local folding is responsible for the loss of nuclear translocation activity (Padhi et al., 2012 Padhi, A. K., Kumar, H., Vasaikar, S. V., Jayaram, B. and Gomes, J. 2012. Mechanisms of loss of functions of human angiogenin variants implicated in amyotrophic lateral sclerosis. PLoS One, 7(2): e32479[PubMed] [Google Scholar]; AK, 2013 Padhi, A.K., Jayaram, B., & Gomes, J. (accepted for publication). Prediction of functional loss of human angiogenin mutants associated with ALS by molecular dynamics simulations. Scientific Reports (NPG).  [Google Scholar]). Our prediction of loss-of-functions of 17 ANG mutants correlated positively with the reported experimental results. We have subsequently developed a fast molecular dynamics method based on certain global attributes / dynamic markers that can be used to determine whether a mutation is deleterious or benign. To make our method accessible to researchers and clinicians, we created a web server-based tool, ANGDelMut, freely available at http://bioschool.iitd.ernet.in/research.htm, where a user can submit new mutations to ascertain whether they cause ALS. We hope that our method will benefit the community at large and will pave the way for the development of a successful therapy for patients suffering from ALS.  相似文献   

15.
Background: Sporadic fatal insomnia (sFI) is a rapid progressive neurodegenerative disease characterised by gradual to perpetual insomnia, followed by dysautonomia, coma and death.1 Lugaresi E, Medori R, Montagna P, Baruzzi A, Cortelli P, Lugaresi A, Tinuper P, Zucconi M, Gambetti P. Fatal familial insomnia and dysautonomia with selective degeneration of thalamic nuclei. New England J of Med. 1986;315:9971003. doi:10.1056/NEJM198610163151605.[Crossref], [PubMed], [Web of Science ®] [Google Scholar] The cause of sFI was recently mapped to a mutation in a protein, the prion, found in the human brain. It is the unfolding of the prion that leads to the generation of toxic oligomers that destroy brain tissue and function. Recent studies have confirmed that a methionine mutation at codon 129 of the human Prion is characteristic of sFI. Current treatment slows down the progression of the disease, but no cure has been found, yet. Methods: We used Molecular Docking and Molecular Dynamics simulation methods, to study the toxic Fatal-Insomnia-prion conformations at local unfolding. The idea was to determine these sites and to stabilise these regions against unfolding and miss-folding, using a small ligand, based on a phenothiazine "moiety". Conclusion: As a result we here discuss current fatal insomnia therapy and present seven novel possible compounds for in vitro and in vivo screening.  相似文献   

16.
Aggressive constricting including asphyxiation was observed in wild octopuses (Octopus cyanea Gray, 1849, and Wunderpus photogenicus Hochberg, Norman & Finn, 2006 Hochberg, F.G., Norman, M.D. & Finn, J. (2006) Wunderpus photogenicus n. gen. and sp., a new Octopus from the shallow waters of the Indo-Malayan Archipelago (Cephalopoda: Octopodidae). Molluscan Research 26, 128140.[Web of Science ®] [Google Scholar]). The distal portion of a dorsolateral arm formed a loop around the mantle of another octopus, in at least one case preventing the flow of water into the mantle, over the gills and out of the funnel. Constricting also may have prevented the subordinate individual from releasing ink, a possible irritant and predator attractant. A female O. cyanea used constricting as a form of fatal aggression to asphyxiate a male as part of apparent sexual cannibalism. This female killed a male with which she was mating using the ‘distance’ position. Constriction allowed a W. photogenicus to win during physical interspecific aggression with a close relative, Thaumoctopus mimicus Norman & Hochberg, 2005 Norman, M.D. & Hochberg, F.G. (2005) The ‘Mimic Octopus’ (Thaumoctopus mimicus n. gen. et. sp.), a new octopus from the tropical Indo-West Pacific (Cephalopoda: Octopodidae). Molluscan Research 25, 5770. [Google Scholar]. This action took place near an immediately available food source and interrupted foraging by T. mimicus, providing possible evidence of interference competition among closely related sympatric cephalopod species in the wild.  相似文献   

17.
Abstract

Two series of novel fluorinated nucleosides dimers with an unnatural 1,2,3-triazole linkage were synthesized. The obtained molecules were prepared using “click” chemistry approach based on copper(I) catalyzed Huisgen azide–alkyne cycloaddition. It was performed between 3′- and 5′-azido-nucleosides as the azide components, and the 3′-O- and 5′-O-propargyl-nucleosides as the alkyne components. Based on analysis of the 3 Brunton, L. L.; Lazo, J. S.; Parker, K. L. (Eds.), Goodman & Gilman’s the Pharmacological Basis of Therapeutics, 11th ed.; McGraw-Hill, Medical Publishing Division: New York, NY, 2006. [Google Scholar]JHH, 3 Brunton, L. L.; Lazo, J. S.; Parker, K. L. (Eds.), Goodman & Gilman’s the Pharmacological Basis of Therapeutics, 11th ed.; McGraw-Hill, Medical Publishing Division: New York, NY, 2006. [Google Scholar]JH1′C2 and 3 Brunton, L. L.; Lazo, J. S.; Parker, K. L. (Eds.), Goodman & Gilman’s the Pharmacological Basis of Therapeutics, 11th ed.; McGraw-Hill, Medical Publishing Division: New York, NY, 2006. [Google Scholar]JH1′C6 we estimated conformational preferences of sugar part and orientation around glycosidic bond. All described nucleosides dimers analogs were characterized by spectroscopic methods and evaluated for their in vitro cytotoxicity in three human cancer cell lines: cervical (HeLa), oral (KB) and breast (MCF-7).  相似文献   

18.
ABSTRACT

Discovered in 1954 by Ambroggi and Lapparent, the Tagragra tracksite (Maastrichtian, Agadir, Morocco) yielded tracks of theropod dinosaurs, birds and enigmatic forms tentatively attributed to Lacertilia under the name Agadirichnus elegans. The original specimens are today considered to be lost, and the status of A. elegans has been questioned, even though these footprints can retrospectively be referred to pterodactyloid pterosaur tracks. In order to discuss the status of these foot prints, the historical site has been actively sought and recently rediscovered by one of us (MdD). New material confirms the presence of pterodactyloid footprints, with two morphotypes, in two different facies, respectively associated with bird and theropod tracks. Morphotype I is tentatively conferred to Pteraichnus Stokes 1957 Stokes, W. L. 1957. Pterodactyl tracks from the Morrison Formation. Journal of Palaeontology, 31:9524.[Web of Science ®] [Google Scholar], which extends the stratigraphical distribution of this ichnotaxon to the Maastrichtian. Morphotype II corresponds to the original ichnospecies A. elegans Ambroggi and Lapparent 1954 Ambroggi, R., and A. F. de Lapparent 1954. Les empreintes de pas fossiles du Maestrichtien d'Agadir. Notes du Service Géologique du Maroc, 10:436. [Google Scholar], which is here reassessed as a valid ichnotaxon, with the designation of a neotype. Thus, A. elegans Ambroggi and Lapparent 1954 Ambroggi, R., and A. F. de Lapparent 1954. Les empreintes de pas fossiles du Maestrichtien d'Agadir. Notes du Service Géologique du Maroc, 10:436. [Google Scholar] is historically the first pterosaurian ichnotaxon ever described.  相似文献   

19.
Recent adaptationist accounts of human mental and physical health have reinvigorated the debate over the evolution of human intelligence. In the tradition of strong inference the current study was developed to determine whether either Miller's (1998 Miller, G. F. 1998. “How mate choice shaped human nature: A review of sexual selection and human evolution”. In Handbook of evolutionary psychology: Ideas, issues, and applications, Edited by: Crawford, C. and Krebs, D. 87129. Hillsdale, NJ: Lawrence Erlbaum.  [Google Scholar], 2000a Miller, G. F. 2000a. Mental traits as fitness indicators: Expanding evolutionary psychology's adaptationism. Evolutionary approaches to human reproductive behavior. Ann N Y Acad Sci, 907: 6274. [Crossref], [PubMed], [Web of Science ®] [Google Scholar]) Fitness Indicator Theory or Rushton's (1985 Rushton, J. P. 1985. Differential K theory: The sociobiology of individual and group differences. Pers Indiv Diff, 6(4): 441452. [Crossref] [Google Scholar], 2000 Rushton, J. P. 2000. Race, evolution, and behavior: A life-history perspective, 3rd, Port Huron, MI: Charles Darwin Research Institute.  [Google Scholar]) Differential-K Theory better accounts for general intelligence (“g”) in an undergraduate university population (N = 192). Owing to the lengthy administration time of the test materials, a newly developed 18-item short form of the Ravens Advanced Progressive Matrices (APM-18; Sefcek, Miller, and Figueredo 2007 Sefcek, J. A., Miller, G. F. and Figueredo, A. J. 2007. “Development and of an 18-item short form of the Ravens Advanced Progressive Matrices (RAPM-18). (Submitted)”.  [Google Scholar]) was used. A significant, positive relationship between K and F (r = .31, p < .001) emerged. Contrary to predictions, no significant relationships were found between “g” and either K or F (r = –.09, p ≥ .05 and r = .11, p ≥ .05, respectively). Though generally contrary to both hypotheses, these results may be explained in relation to antagonistic pleiotropy and a potential failure to derive correct predictions for within-species comparisons directly from the results of between-species comparisons.  相似文献   

20.
Abstract

A new ichnofossiliferous locality in Salta Province (northwest Argentina) contains an association with numerous irregular spiral traces assigned to Spirodesmos milanai n. isp., in mature sandstones and quartzites with rippled bedding surfaces, rare wavy lamination and cross-bedded stratification. This record of early spiral behavior is interpreted as a primitive grazing method formed on muddy laminae above sand layers, and is related to a feeding strategy of an annelid-type of organism. Associated traces are Cruziana cf. semiplicata, Diplocraterion isp., Monocraterion isp., Rusophycus isp., Skolithos linearis Haldeman and Skolithos magnus Howell. The ichnoassemblage is similar to a shallow-water ichnoassociation from the Permian Ecca Group of South Africa (Mason et al., 1983 Mason, T. R., Stanistreet, I. G. and Tavener-Smith, R. 1983. Spiral trace fossils from the Permian Ecca Group of Zululand. Lethaia, 16: 241247. [Crossref], [Web of Science ®] [Google Scholar]).  相似文献   

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