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101.
J M Stephens G J Bagby P H Pekala R E Shepherd J J Spitzer C H Lang 《Biochemical and biophysical research communications》1992,183(2):417-422
To understand the molecular mechanisms responsible for the sepsis-induced enhanced glucose uptake, we have examined the levels of GLUT4 and GLUT1 mRNA and protein in the adipose tissue of septic animals. Rats were challenged with a nonlethal septic insult where euglycemia was maintained and hexose uptake in adipose tissue was markedly elevated. Northern blot analysis of total RNA isolated from epididymal fat pads indicated differential regulation of the mRNA content for the two transporters: GLUT1 mRNA was increased 2.6 to 4.6-fold, while GLUT4 mRNA was decreased by 2.5 to 2.9-fold. Despite the difference in mRNA levels, both GLUT1 and GLUT4 protein were down regulated in plasma membranes (40% and 25%, respectively) and microsomal membranes (42% and 25%, respectively) of the septic animals. The increased glucose uptake cannot be explained by the membrane content of GLUT1 and GLUT4 protein. Thus, during hypermetabolic sepsis, increased glucose utilization by adipose tissue is dependent on alternative processes. 相似文献
102.
Zora Svab Elisabeth C Harper Jonathan D. G. Jones Pal Maliga 《Plant molecular biology》1990,14(2):197-205
The bacterial gene aad A encodes the enzyme aminoglycoside-3-adenyltransferase that confers resistance to spectinomycin and streptomycin in Escherichia coli. Chimeric genes have been constructed for expression in plants, and were introduced into Nicotiana tabacum by Agrobacterium binary transformation vectors. Spectinomycin or streptomycin in selective concentrations prevent greening of N. tabacum calli. Transgenic clones, however, formed green calli on selective media containing spectinomycin, streptomycin, or both drugs. Resistance was inherited as a dominant Mendelian trait in the seed progeny. Resistance conferred by the chimeric aad A gene can be used as a color marker similar to the resistance conferred by the streptomycin phosphotransferase gene to streptomycin. 相似文献
103.
R. C. H. Shepherd 《BioControl》1990,35(4):583-587
Host specificity tests carried out in the laboratory in Australia during 1977, showed thatMicrothrix inconspicuella Ragonot could develop on young apple leaves (Harley
et al., 1979). Field studies in unsprayed apple orchards in South Africa showed that some feeding occurred, but fewer than 40% of
late instar larvae developed to adults when confined in sleeves on apple tree branches. No feeding or survival occurred in
large field cages or in the open. Adults which developed from apple fed larvae were smaller, deformed, occasionally mated
and laid fertile eggs but their progeny did not feed or develop on apple fruit or leaves. In conclusion,M. inconspicuella larvae did not develop on apple fruit or leaves in the field, damage was mainly limited to apples already injured and feeding
on leaves was minimal. Under normal pest control practicesM. inconspicuella populations did not survive on any part of the apple tree or onE. australis growing under the trees.
相似文献
104.
Rosamond C. H. Shepherd 《BioControl》1990,35(3):441-447
Host specificity tests of the moth,Microthrix inconspicuella Ragonot in Australia, indicated that larvae could feed and develop on young apple leaves. Additional tests in South Africa
on leaves and fruit of the 4 apple varieties, Jonathan, Starking (Red Delicious), Granny Smith and Golden Delicious, showed
that apples were not a preferred food. Little feeding occurred and pupation happened infrequently. No 2nd generation resulted whenM. inconspicuella colonies were confined on apple fruit or leaves.
相似文献
105.
Heterogeneity of the glutathione transferase genes encoding enzymes responsible for insecticide degradation in the housefly 总被引:6,自引:0,他引:6
Michael Syvanen Zonghan Zhou Jonathan Wharton Claire Goldsbury Alan Clark 《Journal of molecular evolution》1996,43(3):236-240
One of the four glutathione-S-transferases (GST) that is overproduced in the insecticide-resistant Cornell-R strain of the housefly (Musca domestica) produces an activity that degrades the insecticide dimethyl parathion and conjugates glutathione to lindane. In earlier
work, it was shown that the resistant Cornell-R carries an amplification, probably a duplication, of one or more of its GST
loci and that this amplification is directly related to resistance. Using polymerase chain reaction (PCR) amplification with
genomic DNA, multiple copies of the gene encoding the parathion-degrading activity (called MdGst-3) were subcloned from both
the ancestral, insecticide-susceptible strain BPM and from the insecticide-resistant Cornell-R. In BPM, three different MdGst-3
genes were identified while in Cornell-R, 12 different MdGst-3 sequences were found that, though closely related to ancestral
genes, had diverged by a few nucleotides. This diversity in MdGst-3 genomic sequences in Cornell-R is reflected in the expressed
sequences, as sampled through a cDNA bank. Population heterozygosity cannot account for these multiple GST genes. We suggest
that selection for resistance to insecticides has resulted in not only amplification of the MdGst-3 genes but also in the
divergence of sequence between the amplified copies.
Received: 22 November 1995 / Accepted: 23 February 1996 相似文献
106.
The small (116 amino acids) inner membrane protein MerT encoded by the transposon Tn501 has been overexpressed under the control of the bacteriophage T7 expression system. Random mutants of MerT were made and screened for loss of mercuric ion hypersensitivity. Several mutantmerT genes were selected and sequenced: Cys24Arg and Cys25Tyr mutations abolish mercury resistance, as do charge-substitution mutations in the first predicted transmembrane helix (Glyl4Arg, Glyl5Arg, Gly27Arg, Ala18Asp), and the termination mutations Trp66Ter and Cys82Ter. 相似文献
107.
Jonathan A. Lindquist Elisabeth Barofsky Philip N. McFadden 《Journal of Protein Chemistry》1996,15(1):115-122
Protein (d-aspartyl/l-isoaspartyl) carboxyl methyltransferase (PCM, E.C. 2.1.1.77) was previously shown to be enzymatically methyl esterified in an autocatalytic manner at altered aspartyl residues; methyl esters are observed in a subpopulation of the enzyme termed thePCM fraction [Lindquist and McFadden (1994),J. Protein Chem.
13, 23–30]. The altered aspartyl sites serving as methyl acceptors inPCM have now been localized by using proteolytic enzymes and chemical cleavage techniques in combination with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to identify fragments of the [3H]automethylated enzyme that contain a [3H]methyl ester. Methylation was positively identified at positions Asn188 and Asp217 in the enzyme sequence, a consequence of the spontaneous alteration of these sites tol-isoaspartyl ord-aspartyl sites and their methylation by active PCM molecules. The identification of more than one site of automethylation shows thatPCM is not a homogeneous population of damaged PCM molecules, but rather a complex population of molecules with a variety of age-altered damage sites.Abbreviations PCM
protein (d-aspartyl/l-isoaspartyl) carboxyl methyltransferase
- EDTA
disodium ethylenediaminetetraacetate
- PMSF
phenylmethylsulfonyl fluoride
- TEA
trifluoroacetic acid
- HPLC
high-pressure liquid chromatography 相似文献
108.
Luke Olsen Jonathan A. Sherratt Philip K. Maini 《Bulletin of mathematical biology》1996,58(4):787-808
The normal process of dermal wound healing fails in some cases, due to fibro-proliferative disorders such as keloid and hypertrophic
scars. These types of abnormal healing may be regarded as pathologically excessive responses to wounding in terms of fibroblastic
cell profiles and their inflammatory growth-factor mediators. Biologically, these conditions are poorly understood and current
medical treatments are thus unreliable.
In this paper, the authors apply an existing deterministic mathematical model for fibroplasia and wound contraction in adult
mammalian dermis (Olsenet al., J. theor. Biol.
177, 113–128, 1995) to investigate key clinical problems concerning these healing disorders. A caricature model is proposed which
retains the fundamental cellular and chemical components of the full model, in order to analyse the spatiotemporal dynamics
of the initiation, progression, cessation and regression of fibro-contractive diseases in relation to normal healing. This
model accounts for fibroblastic cell migration, proliferation and death and growth-factor diffusion, production by cells and
tissue removal/decay.
Explicit results are obtained in terms of the model processes and parameters. The rate of cellular production of the chemical
is shown to be critical to the development of a stable pathological state. Further, cessation and/or regression of the disease
depend on appropriate spatiotemporally varying forms for this production rate, which can be understood in terms of the bistability
of the normal dermal and pathological steady states—a central property of the model, which is evident from stability and bifurcation
analyses.
The work predicts novel, biologically realistic and testable pathogenic and control mechanisms, the understanding of which
will lead toward more effective strategies for clinical therapy of fibro-proliferative disorders. 相似文献
109.
Sojourners: The Return of German Jews and the Question of Identity. John Borneman and Jeffrey M. Peck. Lincoln
Recovered Roots: Collective Memory and the Making of Israeli National Tradition. Yael Zerubavel. Chicago
The Masada Myth: Collective Memory and Mythmaking in Israel. Nachman Ben-Yehuda. Madison 相似文献
Recovered Roots: Collective Memory and the Making of Israeli National Tradition. Yael Zerubavel. Chicago
The Masada Myth: Collective Memory and Mythmaking in Israel. Nachman Ben-Yehuda. Madison 相似文献
110.
An evaluation of methods for the simultaneous detection of Cryptosporidium oocysts and Giardia cysts from water. 总被引:2,自引:0,他引:2 下载免费PDF全文
Methods for the simultaneous detection of Cryptosporidium parvum oocysts and Giardia cysts from water are described and their relative recovery efficiencies are assessed for seeded samples of both tap and river water. Cartridge filtration, membrane filtration, and calcium carbonate flocculation were evaluated, and steps to optimize the concentration procedures were undertaken. Increasing centrifugation to 5,000 x g, coupled with staining in suspension, was found to increase the overall efficiency of recovery of both cysts and oocysts. Cartridge filtration for both cysts and oocysts was examined by use of 100-liter volumes of both tap and river water. Improvements in recovery were observed for Cryptosporidium oocysts after extra washes of the filters. Calcium carbonate flocculation gave the maximum recovery for both Cryptosporidium oocysts and Giardia cysts and for both water types. A variety of 142-mm membranes was examined by use of 10-liter seeded samples of tap and river water. Cellulose acetate with a 1.2-micron pore size provided the best results for Cryptosporidium oocysts, and cellulose nitrate with a 3.0-micron pore size did so for Giardia cysts. 相似文献