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21.
Bani-Yaghoub M Kendall SE Moore DP Bellum S Cowling RA Nikopoulos GN Kubu CJ Vary C Verdi JM 《Development (Cambridge, England)》2004,131(17):4287-4298
Reports of non-neural differentiation of neural stem cells (NSCs) have been challenged by alternative explanations for expanded differentiation potentials. In an attempt to demonstrate the plasticity of NSC, neurospheres were generated from single retrovirally labeled embryonic cortical precursors. In a defined serum-free insulin-containing media, 40% of the neurospheres contained both myogenic and neurogenic differentiated progeny. The number of NSCs displaying multilineage differentiation potential declines through gestation but does exist in the adult animal. In this system, insulin appears to function as a survival and dose-dependent myogenic differentiation signal for multilineage NSCs (MLNSC). MLNSC-derived cardiomyocytes contract synchronously, respond to sympathetic and parasympathetic stimulation, and regenerate injured heart tissues. These studies provide support for the hypothesis that MLNSCs exist throughout the lifetime of the animal, and potentially provide a population of stem cells for cell-based regenerative medicine strategies inside and outside of the nervous system. 相似文献
22.
Yeast Isw1p forms two separable complexes in vivo 总被引:2,自引:0,他引:2
23.
Vary TC Kimball SR 《American journal of physiology. Endocrinology and metabolism》2000,279(5):E1178-E1184
Chronic septic abscess formation causes an inhibition of protein synthesis in gastrocnemius that is not observed in rats with a sterile abscess. The inhibition is associated with an impaired translation initiation. The present study was designed to investigate the effects of sepsis on phosphorylation and availability of eukaryotic initiation factor (eIF)4E in gastrocnemius 5 days after induction of a sterile or septic abscess. Neither sepsis nor sterile inflammation altered the extent of eIF4E phosphorylation. Moreover, no changes in the amount of the binding protein 4E-BP1 associated with eIF4E or in the phosphorylation of 4E-BP1 were observed during sepsis or sterile inflammation. In contrast, sepsis and sterile inflammation caused a reduction in the relative amount of eIF4G bound to eIF4E compared with controls. The diminished amount of eIF4G bound to eIF4E was not the result of a reduced abundance of eIF4E. Sepsis, but not sterile inflammation, caused an increase in the cellular abundance of eIF4E. The results provide evidence that alterations in the eIF4E system are probably not rate controlling for the synthesis of total, mixed proteins in gastrocnemius during sepsis. Instead, on the basis of our previous studies, changes in eIF2B appear to be responsible for limiting protein synthesis in skeletal muscle during sepsis. 相似文献
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26.
M. J. Pettinari G. J. Vazquez N. Krüger P. S. Vary A. Steinbüchel B. S. Méndez 《Applied microbiology and biotechnology》1998,49(6):737-742
A Bacillus megaterium genomic fragment, which encoded an activator homologous to σ54 regulators and which was capable of activating Escherichia coli ato genes in trans, was detected in a gene library of B.␣megaterium screened for β-ketothiolase activity. The fragment presented only one complete open reading frame (ORF1), which encoded a
protein of 398 amino acids. The recombinant plasmid complemented mutations in the Escherichia coli atoC regulatory gene. The constitutive expression of the E. coli ato operon mediated by ORF1 could be useful for the synthesis of polyhydroxyalkanoates with different flexibility properties
by recombinant E. coli strains.
Received: 20 October 1997 / Received revision: 18 February 1998 / Accepted: 23 February 1998 相似文献
27.
<Emphasis Type="Italic">Bacillus megaterium</Emphasis>—from simple soil bacterium to industrial protein production host 总被引:2,自引:0,他引:2
Vary PS Biedendieck R Fuerch T Meinhardt F Rohde M Deckwer WD Jahn D 《Applied microbiology and biotechnology》2007,76(5):957-967
Bacillus megaterium has been industrially employed for more than 50 years, as it possesses some very useful and unusual enzymes and a high capacity
for the production of exoenzymes. It is also a desirable cloning host for the production of intact proteins, as it does not
possess external alkaline proteases and can stably maintain a variety of plasmid vectors. Genetic tools for this species include
transducing phages and several hundred mutants covering the processes of biosynthesis, catabolism, division, sporulation,
germination, antibiotic resistance, and recombination. The seven plasmids of B. megaterium strain QM B1551 contain several unusual metabolic genes that may be useful in bioremediation. Recently, several recombinant
shuttle vectors carrying different strong inducible promoters and various combinations of affinity tags for simple protein
purification have been constructed. Leader sequences-mediated export of affinity-tagged proteins into the growth medium was
made possible. These plasmids are commercially available. For a broader application of B. megaterium in industry, sporulation and protease-deficient as well as UV-sensitive mutants were constructed. The genome sequence of
two different strains, plasmidless DSM319 and QM B1551 carrying seven natural plasmids, is now available. These sequences
allow for a systems biotechnology optimization of the production host B. megaterium. Altogether, a “toolbox” of hundreds of genetically characterized strains, genetic methods, vectors, hosts, and genomic sequences
make B. megaterium an ideal organism for industrial, environmental, and experimental applications. 相似文献
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29.
Robert P. Smith Bruce Cahill Charles Lubelczyk Susan P. Elias Eleanor Lacombe Sara R. Morris Calvin P. Vary Christine E. Parent Peter W. Rand 《Journal of vector ecology》2011,36(1):24-29
The role of migratory birds in the dispersal of Ixodes scapularis ticks in the northeastern U.S. is well established and is presumed to be a major factor in the expansion of the geographic risk for Lyme disease. Population genetic studies of B. burgdorferi sensu stricto, the agent of Lyme disease in this region, consistently reveal the local presence of as many as 15 distinct strain types as designated by major groups of the ospC surface lipoprotein. Recent evidence suggests such strain diversity is adaptive to the diverse vertebrate hosts that maintain enzootic infection. How this strain diversity is established in emergent areas is unknown. To determine whether similar strain diversity is present in ticks imported by birds, we examined B. burgdorferi strains in I. scapularis ticks removed from migrants at an isolated island site. Tick mid‐guts were cultured and isolates underwent DNA amplification with primers targeting ospC. Amplicons were separated by gel electrophoresis and sequenced. One hundred thirty‐seven nymphal ticks obtained from 68 birds resulted in 24 isolates of B. burgdorferi representing eight ospC major groups. Bird‐derived ticks contain diverse strain types of B. burgdorferi, including strain types associated with invasive Lyme disease. Birds and the ticks that feed on them may introduce a diversity of strains of the agent of Lyme disease to emergent areas. 相似文献
30.
Bacillus megaterium QM B1551 contains seven plasmids. Two are small rolling circle plasmids and five are theta-replicating plasmids with cross-hybridizing replicons that define a new family of very homologous yet compatible theta replicons. Previous sequencing of several of the plasmids has shown genes with high similarity to those on the genomes and plasmids of other Gram-positive bacteria. To test the possible distribution of these plasmids, nine other B. megaterium strains and 20 other Bacillus or related species were tested for the presence of similar replicons, and specific flanking DNA by both hybridization and PCR. The theta replicons were widespread among the B. megaterium strains, and two had one or more of the rolling circle plasmids, but none of the plasmid replicon regions were observed in the other Bacillus or related species. It appears from the data that even though some plasmids carry genes suggesting horizontal transfer, their replicons seem to be unique to B. megaterium, or rarely present in related species. 相似文献