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1.
《Critical reviews in biochemistry and molecular biology》2013,48(5):409-435
Telomere DNA-binding proteins protect the ends of chromosomes in eukaryotes. A subset of these proteins are constructed with one or more OB folds and bind with G+T-rich single-stranded DNA found at the extreme termini. The resulting DNA-OB protein complex interacts with other telomere components to coordinate critical telomere functions of DNA protection and DNA synthesis. While the first crystal and NMR structures readily explained protection of telomere ends, the picture of how single-stranded DNA becomes available to serve as primer and template for synthesis of new telomere DNA is only recently coming into focus. New structures of telomere OB fold proteins alongside insights from genetic and biochemical experiments have made significant contributions towards understanding how protein-binding OB proteins collaborate with DNA-binding OB proteins to recruit telomerase and DNA polymerase for telomere homeostasis. This review surveys telomere OB protein structures alongside highly comparable structures derived from replication protein A (RPA) components, with the goal of providing a molecular context for understanding telomere OB protein evolution and mechanism of action in protection and synthesis of telomere DNA. 相似文献
2.
P. G. LADD S. W. CONNELL 《Botanical journal of the Linnean Society. Linnean Society of London》1994,116(1):77-88
It has been suggested by some authors that the low fruit to flower ratio in some Proteaceae is due to andromonoecy, while others, looking particularly at Banksia , have not been able to find evidence for male flowers in the inflorescences. Stirlingia latifolia, Xylomelum occidentals and X. angustifolium are clearly andromonoecous, while no evidence for this condition could be found in Brabejum stellatifoliutn. Production of fertile fruit is related to andromonoecy in Xylomelum and S. latifolia but not in Brabejum. It is unlikely that all-encompassing solutions will be found to what initially seem to be widespread traits in the family, especially in regard to pollination biology, as the genera in the family occupy widely different environments and have very diverse ecological ranges. 相似文献
3.
D. Tab Rasmussen 《International journal of primatology》1985,6(5):501-517
Breeding records of 11 taxa of captive lemurs housed at the Duke University Primate Center (DUPC), North Carolina, were analyzed
for differences in the timing of births, for the relationship between breeding season and photoperiod, and for differences
in litter size. At DUPC there are significant differences in the timing of births among certain taxa, including differences
among some subspecies of Lemur fulvus.However, changes in latitude result in changes in the timing of the breeding season. Lemurs moved to higher latitudes mate
at lower light-dark ratios than on Madagascar. The data presented here are consistent with the following model: a photoperiodic
cue initiating reproductive activity, presumably a light-dark threshold, precedes the actual mating season by approximately
2 months, with an intervening period of physiological and social preparation. On Madagascar, selection may have favored births
that coincide with the end of dry seasons and the beginning of wet seasons, which results in lactation and weaning during
times of resource abundance. Taxa from the north and east have the highest mean litter sizes; those from the west have the
lowest. 相似文献
4.
W. Kelley Thomas J. T. Vida Linda M. Frisse Manuel Mundo James G. Baldwin 《Journal of nematology》1997,29(3):250-254
To effectively integrate DNA sequence analysis and classical nematode taxonomy, we must be able to obtain DNA sequences from formalin-fixed specimens. Microdissected sections of nematodes were removed from specimens fixed in formalin, using standard protocols and without destroying morphological features. The fixed sections provided sufficient template for multiple polymerase chain reaction-based DNA sequence analyses. 相似文献
5.
Giovanni Murtas 《Systems and synthetic biology》2010,4(2):85-93
One of the major properties of the semi-synthetic minimal cell, as a model for early living cells, is the ability to self-reproduce
itself, and the reproduction of the boundary layer or vesicle compartment is part of this process. A minimal bio-molecular
mechanism based on the activity of one single enzyme, the FAS-B (Fatty Acid Synthase) Type I enzyme from Brevibacterium ammoniagenes, is encapsulated in 1-palmitoyl-2oleoyl-sn-glycero-3-phosphatidylcholine (POPC) liposomes to control lipid synthesis. Consequently molecules of palmitic acid released
from the FAS catalysis, within the internal lumen, move toward the membrane compartment and become incorporated into the phospholipid
bilayer. As a result the vesicle membranes change in lipid composition and liposome growth can be monitored. Here we report
the first experiments showing vesicles growth by catalysis of one enzyme only that produces cell boundary from within. This
is the prototype of the simplest autopoietic minimal cell. 相似文献
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9.
P. Cruz C. H. Mejia‐Ruiz R. Perez‐Enriquez A. M. Ibarra 《Molecular ecology resources》2002,2(3):239-241
Five polymorphic microsatellite loci were characterized for Penaeus (Litopenaeus) vannamei. Loci were isolated using a partial Sau3A1 genomic library by the sequencing of randomly selected clones and by a biotinylated (CT)10 and (GT)10 probes screening procedure. The last strategy resulted in the most useful data. About 40% of the clones showed a previously reported satellite/microsatellite (PVS1), reducing the chance of finding new microsatellite regions. Whereas two of the microsatellite loci with more than 10 alleles will be useful for mating analysis in a breeding program, the others might prove useful for population genetic studies. 相似文献
10.
J. Lançon J.-P. Pichaut M. Djaboutou S. Lewicki-Dhainaut C. Viot & J.-M. Lacape 《The Annals of applied biology》2008,152(1):113-119
In participatory plant breeding, farmers are involved in simple selection schemes that are not suitable for assessing genetic variability in the segregating populations. We propose to use information derived from molecular marker analyses to help monitoring such populations. In this study, we used three indicators to compare genetic variability in eight genetic structures, that is three plant populations selected by farmers over five generations, three nonselected populations and two commercial varieties. The three indicators were the polymorphic locus rate, heterozygosity rate and dissimilarity index. The results highlighted that the genetic variability decreased more with farmers’ selection than with environmental factors. The breeding process was not complete because genetic variability in the selected populations was midway between that of the nonselected populations and that of the commercial varieties monitored. The three proposed indicators were relevant for describing the studied populations. They could be interpreted according to a grid drawn up on the basis of the results of the present study. 相似文献