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41.
The structural properties, NMR and NQR parameters in the pristine and silicon carbide (SiC) doped boron phosphide nanotubes
(BPNTs) were calculated using DFT methods (BLYP, B3LYP/6-31G*) in order to evaluate the influence of SiC-doped on the (4,4)
armchair BPNTs. Nuclear magnetic resonance (NMR) parameters including isotropic (CSI) and anisotropic (CSA) chemical shielding parameters for the sites of various 13C, 29Si, 11B, and 31P atoms and quadrupole coupling constant (C
Q
), and asymmetry parameter (η
Q
) at the sites of various 11B nuclei were calculated in pristine and SiC- doped (4,4) armchair boron phosphide nanotubes models. The calculations indicated that doping of 11B and 31P atoms by C and Si atoms had a more significant influence on the calculated NMR and NQR parameters than did doping of the
B and P atoms by Si and C atoms. In comparison with the pristine model, the SiC- doping in SiPCB model of the (4,4) armchair BPNTs reduces the energy gaps of the nanotubes and increases their electrical conductance. The NMR results showed that the
B and P atoms which are directly bonded to the C atoms in the SiC-doped BPNTs have significant changes in the NMR parameters
with respect to the B and P atoms which are directly bonded to the Si atoms in the SiC-doped BPNTs. The NQR results showed
that in BPNTs, the B atoms at the edges of nanotubes play dominant roles in determining the electronic behaviors of BPNTs.
Also, the NMR and NQR results detect that the Fig. 1b (SiPCB) model is a more reactive material than the pristine and the Fig. 1a (SiBCp) models of the (4,4) armchair BPNTs. 相似文献
42.
Lucas Bleicher Ricardo Aparicio Fabio M Nunes Leandro Martinez Sandra M Gomes Dias Carolina Migliorini Ana Figueira Auxiliadora Morim Maria Santos Walter H Venturelli Rosangela da Silva Paulo Marcos Donate Francisco AR Neves Luiz A Simeoni John D Baxter Paul Webb Munir S Skaf Igor Polikarpov 《BMC structural biology》2008,8(1):1-13
Background
Multiple protein templates are commonly used in manual protein structure prediction. However, few automated algorithms of selecting and combining multiple templates are available.Results
Here we develop an effective multi-template combination algorithm for protein comparative modeling. The algorithm selects templates according to the similarity significance of the alignments between template and target proteins. It combines the whole template-target alignments whose similarity significance score is close to that of the top template-target alignment within a threshold, whereas it only takes alignment fragments from a less similar template-target alignment that align with a sizable uncovered region of the target. We compare the algorithm with the traditional method of using a single top template on the 45 comparative modeling targets (i.e. easy template-based modeling targets) used in the seventh edition of Critical Assessment of Techniques for Protein Structure Prediction (CASP7). The multi-template combination algorithm improves the GDT-TS scores of predicted models by 6.8% on average. The statistical analysis shows that the improvement is significant (p-value < 10-4). Compared with the ideal approach that always uses the best template, the multi-template approach yields only slightly better performance. During the CASP7 experiment, the preliminary implementation of the multi-template combination algorithm (FOLDpro) was ranked second among 67 servers in the category of high-accuracy structure prediction in terms of GDT-TS measure.Conclusion
We have developed a novel multi-template algorithm to improve protein comparative modeling. 相似文献43.
Cavin4 interacts with Bin1 to promote T-tubule formation and stability in developing skeletal muscle
Harriet P. Lo Ye-Wheen Lim Zherui Xiong Nick Martel Charles Ferguson Nicholas Ariotti Jean Giacomotto James Rae Matthias Floetenmeyer Shayli Varasteh Moradi Ya Gao Vikas A. Tillu Di Xia Huang Wang Samira Rahnama Susan J. Nixon Michele Bastiani Ryan D. Day Kelly A. Smith Nathan J. Palpant Wayne A. Johnston Kirill Alexandrov Brett M. Collins Thomas E. Hall Robert G. Parton 《The Journal of cell biology》2021,220(12)
The cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems, mouse and zebrafish. In both models, Cavin4 localized to T-tubules, and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule–associated BAR domain protein Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function. 相似文献
44.
Horizontal transmission, vertical inactivation, and stochastic loss of mariner-like transposable elements 总被引:13,自引:5,他引:8
Horizontal transmission has been well documented as a major mechanism for
the dissemination of mariner-like elements (MLEs) among species. Less well
understood are mechanisms that limit vertical transmission of MLEs
resulting in the "spotty" or discontinuous distribution observed in closely
related species. In this article we present evidence that the genome of the
common ancestor of the melanogaster species subgroup of Drosophila
contained an MLE related to the mellifera (honey bee) subfamily. Horizontal
transmission, approximately 3-10 MYA, is strongly suggested by the
observation that the sequence of the MLE in Drosophila erecta is 97%
identical in nucleotide sequence with that of an MLE in the cat flea,
Ctenocephalides felis. The D. erecta MLE has a spotty distribution among
species in the melanogaster subgroup. The element has a high copy number in
D. erecta and D. orena, a moderate copy number in D. teissieri and D.
yakuba, and was apparently lost ("stochastic loss") in the lineage leading
to D. melanogaster, D. simulans, D. mauritiana, and D. sechellia. In D.
erecta, most copies are concentrated in the heterochromatin. Two copies
from D. erecta, denoted De12 and De19, were cloned and sequenced, and they
appear to be nonfunctional ("vertical inactivation"). It therefore appears
that the predominant mode of MLE evolution is vertical inactivation and
stochastic loss balanced against occasional reinvasion of lineages by
horizontal transmission.
相似文献
45.
Yeast-like fungi such as Saccharomyces cerevisiae exhibit a range of cell types differing in cell shape, gene expression and growth pattern. Signal transduction pathways mediate transitions between different cell types. Nutritional signals induce rounded yeast-form cells either to enter invasive growth as elongated filamentous cells or to arrest to prepare for stationary phase, conjugation, or meiosis. An emerging theme is that development critically depends upon differential regulation of vegetative functions, including cytoskeletal organization and cell cycle progression, as much as on the expression of cell type specific gene products. 相似文献
46.
Fine needle aspiration biopsies (FNA) of 47 Warthin's tumours confirmed by histology were re-evaluated for cytomorphological findings. The majority of aspirates (37/47) contained a typical background with proteinaceous substance and cell debris, along with cellular elements represented by oncocytic, lymphoid, and mast cells with degranulated cytoplasm. Uncommon cellular findings were true squamous cells (1/47), atypical cells with vacuoles (1/47), osteoclastic giant cells (1/47), epithelioid cells (1/47), mast cells with preserved granules in cytoplasm (3/47), and siderophages (4/47). Uncommon findings in the background were corpora amylacea-like structures and homogeneous bright red droplets. Squamous cells and atypical cells with vacuoles caused diagnostic difficulties in distinguishing a Warthin's tumour from a squamous cell or mucoepidermoid carcinoma. However, other unusual cellular and background findings were not worrying; therefore, they are merely regarded as a curiosity in the cytomorphological appearance of the tumour. 相似文献
47.
Water in the Avian Egg Overall Budget of Incubation 总被引:1,自引:0,他引:1
The loss of mass in eggs during incubation was examined andevidence is presented to show that this is essentially due toloss of water. The mean fraction of water lost by diffusionthroughout incubation is 0.150 ± 0.025 S D per gram ofegg and 0.162 ± 0.026 S D per gram of egg content for81 species. The water fraction of fresh eggs and of hatchingeggs was examined in 32 species divided according to maturityat hatching, and found to be very similar within each category(83% in altricial 83% in semi-altricial 78% in semi-precocial72% in precocial eggs). The 11% difference between the altricialand precocial categories is statistically significant. Duringincubation, dry matter is metabolized increasing the water fractionwhich is further increased by metabolic water production. Hence,water loss during incubation is mandatory if the relative watercontent of an egg at the end of incubation is to remain essentiallythe same as at the beginning. Equations are developed whichallow one to estimate the difference between diffusive waterloss and the total water loss in altricial and piecocial eggscaused by additional water loss during pipping and hatching. 相似文献
48.
Gas Exchange of the Avian Egg Time, Structure, and Function 总被引:1,自引:0,他引:1
Data are presented for oxygen consumption water loss duringincubation water vapor conductance of the shell and pore numberof avian eggs and the way in which these values relate not onlyto egg mass but also to incubation time. It is proposed thatall these functions are proportional to the product of egg massand rate of development where the latter is defined as the inverseof incubation time. These interrelationships account at theend of incubation for similar O2 and CO2 tensions in the airspace of eggs utilization of calories (0.5 kcal g1) andwater loss (15 g g1) 相似文献
49.
S Jahan S Singh A Srivastava V Kumar D Kumar A Pandey CS Rajpurohit AR Purohit VK Khanna AB Pant 《Molecular neurobiology》2018,55(4):2828-2839
50.
Mina Patel-Chamberlin Mujan Varasteh Kia Jie Xu Sharon Barone Kamyar Zahedi Manoocher Soleimani 《PloS one》2016,11(3)