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1.
Structural relatedness of lysis proteins from colicinogenic plasmids and icosahedral coliphages 总被引:4,自引:0,他引:4
The host-lysis-inducing functions of phi X174 protein E and MS2 protein L
were recently shown to reside on the N-terminal and C-terminal halves of
the two respective lysis proteins. In the present study it is shown that
the small lysis proteins encoded in various colicinogenic plasmids share
local sequence similarities and certain structural characteristics with the
essential peptides of their coliphage-coded counterparts. Despite their
dissimilar sizes and origins, it is suggested that the colicinogenic lysis
proteins are functionally analogous and evolutionarily related to those of
icosahedral single- stranded DNA and RNA phages.
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2.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
3.
Secretion of biologically active leech hirudin from baculovirus-infected insect cells. 总被引:1,自引:0,他引:1
The thrombin inhibitor, hirudin, from the leech Hirudo Medicinalis, is the most powerful natural anticoagulant known. It has been characterized as a polypeptide of 65 amino acids which exhibits its anticoagulant properties by binding tightly and specifically to alpha-thrombin. The potency and specificity of hirudin have generated interest on its possible use in the treatment or prophylaxis of various thrombotic diseases. We have used the baculovirus expression system to efficiently produce active hirudins in insect cells. The Autographa californica nuclear polyhedrosis virus has proved useful as a helper-independent viral expression vector for high-level production of recombinant proteins in cultured insect cells. Hirudin variants (HV1 and HV2) were produced in infected insect cells as secreted proteins by joining their coding sequences to the leader peptide sequence of the vescicular stomatitis virus G protein. The recombinant products were biologically active and, interestingly, N-terminal sequencing of HV1 revealed that the heterologous leader peptide is correctly removed. 相似文献
4.
Phillip A Patten Russell J Howard Willem PC Stemmer 《Current opinion in biotechnology》1997,8(6):724-733
DNA shuffling is a practical process for directed molecular evolution which uses recombination to dramatically accelerate the rate at which one can evolve genes. Single and multigene traits that require many mutations for improved phenotypes can be evolved rapidly. DNA shuffling technology has been significantly enhanced in the past year, extending its range of applications to small molecule pharmaceuticals, pharmaceutical proteins, gene therapy vehicles and transgenes, vaccines and evolved viruses for vaccines, and laboratory animal models. 相似文献
5.
Eva Veronesi Frank Antony Simon Gubbins Nick Golding Alison Blackwell Peter PC. Mertens Joe Brownlie Karin E. Darpel Philip S. Mellor Simon Carpenter 《PloS one》2013,8(8)
Background
Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of globally significant arboviruses of livestock including bluetongue virus (BTV), African horse sickness virus (AHSV) and the recently emerging Schmallenberg virus (SBV). From 2006–2009 outbreaks of BTV in northern Europe inflicted major disruption and economic losses to farmers and several attempts were made to implicate Palaearctic Culicoides species as vectors. Results from these studies were difficult to interpret as they used semi-quantitative RT-PCR (sqPCR) assays as the major diagnostic tool, a technique that had not been validated for use in this role. In this study we validate the use of these assays by carrying out time-series detection of BTV RNA in two colony species of Culicoides and compare the results with the more traditional isolation of infectious BTV on cell culture.Methodology/Principal Findings
A BTV serotype 1 strain mixed with horse blood was fed to several hundred individuals of Culicoides sonorensis (Wirth & Jones) and C. nubeculosus (Mg.) using a membrane-based assay and replete individuals were then incubated at 25°C. At daily intervals 25 Culicoides of each species were removed from incubation, homogenised and BTV quantified in each individual using sqPCR (Cq values) and virus isolation on a KC-C. sonorensis embryonic cell line, followed by antigen enzyme-linked immunosorbent assay (ELISA). In addition, comparisons were also drawn between the results obtained with whole C. sonorensis and with individually dissected individuals to determine the level of BTV dissemination.Conclusions/Significance
Cq values generated from time-series infection experiments in both C. sonorensis and C. nubeculosus confirmed previous studies that relied upon the isolation and detection of infectious BTV. Implications on the testing of field-collected Culicoides as potential virus vectors by PCR assays and the use of such assays as front-line tools for use in diagnostic laboratories in this role are discussed. 相似文献6.
Isadore Budnick Emily Hamburg‐Shields Demeng Chen Eduardo Torre Andrew Jarrell Batool Akhtar‐Zaidi Olivia Cordovan Rob C. Spitale Peter Scacheri Radhika P. Atit 《Genesis (New York, N.Y. : 2000)》2016,54(8):415-430
Embryonic dermal fibroblasts in the skin have the exceptional ability to initiate hair follicle morphogenesis and contribute to scarless wound healing. Activation of the Wnt signaling pathway is critical for dermal fibroblast fate selection and hair follicle induction. In humans, mutations in Wnt pathway components and target genes lead to congenital focal dermal hypoplasias with diminished hair. The gene expression signature of embryonic dermal fibroblasts during differentiation and its dependence on Wnt signaling is unknown. Here we applied Shannon entropy analysis to identify the gene expression signature of mouse embryonic dermal fibroblasts. We used available human DNase‐seq and histone modification ChiP‐seq data on various cell‐types to demonstrate that genes in the fibroblast cell identity signature can be epigenetically repressed in other cell‐types. We found a subset of the signature genes whose expression is dependent on Wnt/β‐catenin activity in vivo. With our approach, we have defined and validated a statistically derived gene expression signature that may mediate dermal fibroblast identity and function in development and disease. genesis 54:415–430, 2016. © 2016 Wiley Periodicals, Inc. 相似文献
7.
Peter?C.?Scacheri Judy?S.?Crabtree Alyssa?L.?Kennedy Gary?P.?Swain Jerrold?M.?Ward Stephen?J.?Marx Allen?M.?Spiegel Francis?S.?CollinsEmail author 《Mammalian genome》2004,15(11):872-877
In recent studies from Sweden and the United States, a high vitamin A intake has been associated with low bone mineral density (BMD) and increased fracture risk. In Sweden and the United States, food items such as milk and breakfast cereals are fortified with vitamin A, whereas in Denmark there is no mandatory fortification with vitamin A. In the present study, we investigated relations between vitamin A intake and BMD and fracture risk in a Danish population consuming mostly unfortified food items. Within a population-based cohort study in 2,016 perimenopausal women, associations between BMD and vitamin A intake were assessed at baseline and after 5-year follow-up. Moreover, associations between baseline vitamin A intake and 5-year changes in BMD were studied. Finally, fracture risk was assessed in relation to vitamin A intake. In our cohort, dietary retinol intake (0.53 mg/day) was lower than the intake reported in recent studies form Sweden (0.78 mg/day) and the United States (1.66 mg/day). Cross-sectional and longitudinal analyses showed no associations between intake of vitamin A and BMD of the femoral neck or lumbar spine. Neither did BMD differ between those 5% who had the highest, and those 5% who had the lowest, vitamin A intake. During the 5-year study period, 163 subjects sustained a fracture (cases). Compared to 978 controls, logistic regression analyses revealed no difference in vitamin A intake. Thus, in a Danish population, average vitamin A intake is lower than in Sweden and the United States and not associated with detrimental effects on bone. 相似文献
8.
9.
Phylogenetic relationships were determined for 76 partial P-element
sequences from 14 species of the melanogaster species group within the
Drosophila subgenus Sophophora. These results are examined in the context
of the phylogeny of the species from which the sequences were isolated.
Sequences from the P-element family fall into distinct subfamilies, or
clades, which are often characteristic for particular species subgroups.
When examined locally among closely related species, the evolution of P
elements is characterized by vertical transmission, whereby the P-element
phylogeny traces the species phylogeny. On a broader scale, however, the
P-element phylogeny is not congruent with the species phylogeny. One
feature of P-element evolution in the melanogaster group is the presence of
more than one P-element subfamily, differing by as much as 36%, in the
genomes of some species. Thus, P elements from several individual species
are not monophyletic, and a likely explanation for the incongruence between
P-element and species phylogenies is provided by the comparison of
paralogous sequences. In certain instances, horizontal transfer seems to be
a valid alternative explanation for lack of congruence between species and
P-element phylogenies. The canonical P-element subfamily, which represents
the active, autonomous transposable element, is restricted to D.
melanogaster. Thus, its origin clearly lies outside of the melanogaster
species group, consistent with the earlier conclusion of recent horizontal
transfer.
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