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961.
962.
Vikas A Tillu Ye‐Wheen Lim Oleksiy Kovtun Sergey Mureev Charles Ferguson Michele Bastiani Kerrie‐Ann McMahon Harriet P Lo Thomas E Hall Kirill Alexandrov Brett M Collins Robert G Parton 《EMBO reports》2018,19(9)
Caveolae are plasma membrane invaginations involved in transport, signalling and mechanical membrane sensing in metazoans. Their formation depends upon multiple interactions between membrane‐embedded caveolins, lipids and cytosolic cavin proteins. Of the four cavin family members, only cavin1 is strictly required for caveola formation. Here, we demonstrate that an eleven residue (undecad) repeat sequence (UC1) exclusive to cavin1 is essential for caveolar localization and promotes membrane remodelling through binding to phosphatidylserine. In the notochord of mechanically stimulated zebrafish embryos, the UC1 domain is required for caveolar stability and resistance to membrane stress. The number of undecad repeats in the cavin1 UC1 domain varies throughout evolution, and we find that an increased number also correlates with increased caveolar stability. Lastly, we show that the cavin1 UC1 domain induces dramatic remodelling of the plasma membrane when grafted into cavin2 suggesting an important role in membrane sculpting. Overall, our work defines a novel conserved cavin1 modular domain that controls caveolar assembly and stability. 相似文献
963.
Studies of modern Italian dog populations reveal multiple patterns for domestic breed evolution 下载免费PDF全文
Stefano Frattini Michele Polli Stefano Marelli Alexander C. Harris Luigi Liotta Raffaella Cocco Andrew N. Hogan Daniele Bigi Romolo Caniglia Heidi G. Parker Giulio Pagnacco Elaine A. Ostrander Paola Crepaldi 《Ecology and evolution》2018,8(5):2911-2925
Through thousands of years of breeding and strong human selection, the dog (Canis lupus familiaris) exists today within hundreds of closed populations throughout the world, each with defined phenotypes. A singular geographic region with broad diversity in dog breeds presents an interesting opportunity to observe potential mechanisms of breed formation. Italy claims 14 internationally recognized dog breeds, with numerous additional local varieties. To determine the relationship among Italian dog populations, we integrated genetic data from 263 dogs representing 23 closed dog populations from Italy, seven Apennine gray wolves, and an established dataset of 161 globally recognized dog breeds, applying multiple genetic methods to characterize the modes by which breeds are formed within a single geographic region. Our consideration of each of five genetic analyses reveals a series of development events that mirror historical modes of breed formation, but with variations unique to the codevelopment of early dog and human populations. Using 142,840 genome‐wide SNPs and a dataset of 1,609 canines, representing 182 breeds and 16 wild canids, we identified breed development routes for the Italian breeds that included divergence from common populations for a specific purpose, admixture of regional stock with that from other regions, and isolated selection of local stock with specific attributes. 相似文献
964.
Myrmecochores are plants with seeds adapted for ant dispersal. This specialized dispersal syndrome may provide Erythronium americanum seeds with protection from predators within the eastern deciduous forests. To determine the adaptive significance of myrmecochory in E. americanum, seed removal rates and seed predation in relation to seed release date and location along the Potomac River in Langley, Virginia, were examined. The number of seeds removed from four exclosure treatments were monitored two times in 1992 and three times in 1993 within floodplain and hilltop populations of E. americanum. Overall, seed removal was greatest from control depots, and E. americanum seeds were removed at nearly the same rate from predator-exclusion depots, indicating that removal from open depots is largely due to ant removal. Ants removed significantly more seeds than predators in the first 48 h of seed exposure and could potentially remove all E. americanum seeds before nightfall. Aphaenogaster rudis was identified as the primary disperser of E. americanum. Seeds placed in depots after the natural seed release period were discovered more quickly and removed by ants at a significantly higher rate than seeds released at the natural date. These results suggest that ant dispersal of E. americanum seeds reduces the likelihood of seed predation. 相似文献
965.
The relationship between trinucleotide (GAA) repeat length and clinical features in Friedreich ataxia. 总被引:33,自引:4,他引:29
A. Filla G. De Michele F. Cavalcanti L. Pianese A. Monticelli G. Campanella S. Cocozza 《American journal of human genetics》1996,59(3):554-560
Friedreich ataxia (FA) is associated with the expansion of a GAA trinucleotide repeat in the first intron of the X25 gene. We found both alleles expanded in 67 FA patients from 48 Italian families. Five patients from three families were compound heterozygotes with expansion on one allele and an isoleucine-->phenylalanine change at position 154 on the other one. We found neither expansions nor point mutations in three patients. The length of FA alleles ranged from 201 to 1,186 repeat units, with no overlap with the normal range, and showed a negatively skewed distribution with a peak between 800 and 1,000 repeats. The FA repeat showed meiotic instability with a median variation of 150 repeats. The lengths of both larger and smaller alleles in each patient inversely correlated with age at onset of the disorder. Smaller alleles showed the best correlation, accounting for approximately 50% of the variation of age at onset. Mean allele length was significantly higher in patients with diabetes and in those with cardiomyopathy. 相似文献
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968.
Polysiphonia paniculata Montagne is an intertidal red alga known to produce large amounts of the compound dimethylsulfoniopropionate (DMSP). Conversion of this substrate into dimethylsulfide is accomplished in P, paniculata by an enzyme called DMSP lyase (dimethylpropiothetin dethiomethyla.se (4.4.1.3)). DMSP lyase has been purified and characterized from P. paniculata. Enzymie activity is found in two different proteins: the larger with a molecular weight of 9.26 ± 104 daltons and the smaller with a molecular weight of 3.65 ± 104 daltons. Specific activity of the enzyme is 526 μmols min−1 mg−1 for the smaller protein a nd 263 μmols min −1 mg−1 for the la rger protein. The Michaelis-Menten constant (Km ) is 72.8 μM ± 17.15 and the vmax is 1.62 μmols min−1 ± 0.928 for the 92.6-kDa protein. The p1 of the larger protein is 5.8 and 5.9 for the smaller protein. Interaction with cysteine protease inhibitors L-trans-epoxysuccinyl-leucylamido (4-guanidino)-butane, dithiobis-(2-nitrobenzoate), or N -ethylmaleimide inactivated enzyme activity. The presence of either magnesium or calcium with DMSP lyase enhanced activity al concentrations between 20 and 40 μM but had little effect above these levels. Addition of the divalent chelators ethylenebis(oxyethylenenitrilo) tetraacetic acid and ethylenediaminetetraacetate decreased activity of the enzyme, but activity was restored when either chelator was removed and magnesium or calcium was added to the enzyme . 相似文献
969.
Benedetto Di Blasio Michele Saviano Valerio Del Duca Giuseppina De Simone Filomena Rossi Carlo Pedone Ettore Benedetti Gian Paolo Lorenzi 《Biopolymers》1995,36(4):401-408
The x-ray diffraction analyses of three N- and C-terminally blocked L , D dipeptides, namely t-Boc-D -Leu-L -Leu-OMe ( 1 ), t-Boc-L -Ile-D -alle-OMe ( 2 ), and t-Boc-D -aIle-L -Ile-OMe (3) containing enantiomeric or diastereomeric amino acid residues have been carried out. The structures were determined by direct methods and refined anisotropically to final R factors of 0.077. 0.058. and 0.072 for ( 1 ) ( 2 ) and ( 3 ), respectively. Peptides 1–3 all assume a similar U-shaped structure with ? and ψ torsion angles cosrresponding to one of the possible calculated minimum energy regions (regions E and G for L residues, and F*. D* and H* for D residues). The peptide backbones of 1-3 are almost super-imposable [provided that the appropriate inversion of the chiral centers of ( 2 ) is made]. Side-chain conformations of Leu residues in peptide ( 1 ) are g? (tg?) for the L -Leu residue and the mirrored g+ (tg+) for the D -Leu residue; however, in peptides ( 2 ) and ( 3 ) the conformations of the isoconfiguralional side chains of the Ile or allo-Ile residues are (g?t) t and (tg+) tfor the L -Ile and the D -allo-Ile moieties, respectively. In all cases, these conformations correspond to the more populated conformers of β-branched residues statistically found in crystal structures of small peptides. The results seem to indicate that, at least in short peptides with enantiomeric or diastereoisomeric residues, the change in chirality in the main-chain atoms perturbs the backbone conformation to a lesser extent and the side chain conformation to a greater extent. © 1995 John Wiley & Sons, Inc. 相似文献
970.
Michele Saviano Filomena Rossi Marta Filizola Carla Isernia Benedetto Di Blasio Ettore Benedetti Carlo Pedone Ignacy Z. Siemion Artur Pedyczak 《Biopolymers》1995,36(4):453-460
The solid state conformational analysis of [Tyr4] cyclolinopeptide A has been carried out by x-ray diffraction studies. The crystal structure of the monoclinic form, grown from a dioxane-water mixture [a = 9.849 (5) Å, b = 20.752 (4) Å, c = 16.728 (5) Å, β = 98.83 (3)°, space group P21, Z = 2], shows the presence of five intramolecular N-H? O?C hydrogen bonds, with formation of one C17 ring structure, one α-turn (C13), one inverse γ-turn (C7), and two β-turns (C10, one of type III and one of type 1). The Pro1-Pro2 peptide unit is cis (ω = 5°) all others are trans. The structure is almost superimposable with that of cyclolinopeptide A. The rms deviation for the atoms of the backbones is on the average 0.33 Å. © 1995 John Wiley & Sons, Inc. 相似文献