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Plasminogen activator and collagenase production by cultured capillary endothelial cells 总被引:33,自引:17,他引:16
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Cultured bovine capillary endothelial (BCE) cells produce low levels of collagenolytic activity and significant amounts of the serine protease plasminogen activator (PA). When grown in the presence of nanomolar quantities of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA), BCE cells produced 5-15 times more collagenolytic activity and 2-10 times more PA than untreated cells. The enhanced production of these enzymes was dependent on the dose of TPA used, with maximal response at 10(-7) to 10(-8) M. Phorbol didecanoate (PDD), an analog of TPA which is an active tumor promoter, also increased protease production. 4-O-methyl-TPA and 4α-PDD, two analogs of TPA which are inactive as tumor promoters, had no effect on protease production. Increased PA and collagenase activities were detected within 7.5 and 19 h, respectively, after the addition of TPA. The TPA-stimulated BCE cells synthesized a urokinase-type PA and a typical vertebrate collagenase. BCE cells were compared with bovine aortic endothelial (BAE) cells and bovine embryonic skin (BES) fibroblasts with respect to their production of protease in response to TPA. Under normal growth conditions, low levels of collagenolyic activity were detected in the culture fluids from BCE, BAE, and BES cells. BCE cells produced 5-13 times the basal levels of collagenolytic activity in response to TPA, whereas BAE cells and BES fibroblasts showed a minimal response to TPA. Both BCE and BAE cells exhibited relatively high basal levels of PA, the production of which was stimulated approximately threefold by the addition of TPA. The observation that BCE cells and not BAE cells produced high levels of both PA and collagenase activities in response to TPA demonstrates a significant difference between these two types of endothelial cells and suggests that the enhanced detectable activities are a property unique to bovine capillary and microvessel and endothelial cells. 相似文献
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RODNEY D. BOERTJE MARK A. KEECH THOMAS F. PARAGI 《The Journal of wildlife management》2010,74(5):917-928
ABSTRACT We encourage informed and transparent decision-making processes concerning the recently expanded programs in Alaska, USA, to reduce predation on moose (Alces alces). The decision whether to implement predator control ultimately concerns what society should value; therefore, policymakers, not objective biologists, play a leadership role. From a management and scientific standpoint, biological support for these predator-control programs requires convincing evidence that 1) predators kill substantial numbers of moose that would otherwise mostly live and be available for harvest, 2) low predation can facilitate reliably higher harvests of moose, 3) given less predation, habitats can sustain more moose and be protected from too many moose, and 4) sustainable populations of Alaska's brown bears (Ursus arctos), black bears (Ursus americanus), and wolves (Canis lupus) will exist in and out of control areas. We reviewed 10 moose mortality studies, 36 case histories, 10 manipulative studies, 15 moose nutrition studies, and 3 recent successful uses of nutrition-based management to harvest excess female moose. Results of these studies support application of long-term, substantial predator control for increasing yield of moose in these simple systems where moose are a primary prey of 3 effective predators. We found no substantive, contradictory results in these systems. However, to identify and administer feasible moose population objectives, recently established moose nutritional indices must be monitored, and regulatory bodies must accept nutrition-based management. In addition, the efficacy of techniques to reduce bear predation requires further study. Predicting precise results of predator control on subsequent harvest of moose will continue to be problematic because of a diversity of changing interactions among biological, environmental, and practical factors. In Alaska, the governor has the prerogative to influence regulations on predator control by appointing members to the Board of Game. At least annually, the Board of Game hears a wide spectrum of public opinions opposing and favoring predator control. We summarized these opinions as well as the societal and cultural values and expectations that are often the primary basis for debates. Advocates on both sides of the debate suggest they hold the higher conservation ethic, and both sides provide biased science. We recommend a more constructive and credible dialogue that focuses openly on values rather than on biased science and fabricated conspiracies. To be credible and to add substance in this divisive political arena, biologists must be well informed and provide complete information in an unbiased and respectful manner without exaggeration. 相似文献
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RODNEY D. BOERTJE KALIN A. KELLIE C. TOM SEATON MARK A. KEECH DONALD D. YOUNG BRUCE W. DALE LAYNE G. ADAMS ANDREW R. ADERMAN 《The Journal of wildlife management》2007,71(5):1494-1506
Abstract: We focused on describing low nutritional status in an increasing moose (Alces alces gigas) population with reduced predation in Game Management Unit (GMU) 20A near Fairbanks, Alaska, USA. A skeptical public disallowed liberal antlerless harvests of this moose population until we provided convincing data on low nutritional status. We ranked nutritional status in 15 Alaska moose populations (in boreal forests and coastal tundra) based on multiyear twinning rates. Data on age-of-first-reproduction and parturition rates provided a ranking consistent with twinning rates in the 6 areas where comparative data were available. Also, short-yearling mass provided a ranking consistent with twinning rates in 5 of the 6 areas where data were available. Data from 5 areas implied an inverse relationship between twinning rate and browse removal rate. Only in GMU 20A did nutritional indices reach low levels where justification for halting population growth was apparent, which supports prior findings that nutrition is a minor factor limiting most Alaska moose populations compared to predation. With predator reductions, the GMU 20A moose population increased from 1976 until liberal antlerless harvests in 2004. During 1997-2005, GMU 20A moose exhibited the lowest nutritional status reported to date for wild, noninsular, North American populations, including 1) delayed reproduction until moose reached 36 months of age and the lowest parturition rate among 36-month-old moose (29%, n = 147); 2) the lowest average multiyear twinning rates from late-May aerial surveys (x = 7%, SE = 0.9%, n = 9 yr, range = 3-10%) and delayed twinning until moose reached 60 months of age; 3) the lowest average mass of female short-yearlings in Alaska (x̄ = 155 ± 1.6 [SE] kg in the Tanana Flats subpopulation, up to 58 kg below average masses found elsewhere); and 4) high removal (42%) of current annual browse biomass compared to 9-26% elsewhere in boreal forests. When average multiyear twinning rates in GMU 20A (sampled during 1960-2005) declined to <10% in the mid- to late 1990s, we began encouraging liberal antlerless harvests, but only conservative annual harvests of 61-76 antlerless moose were achieved during 1996-2001. Using data in the context of our broader ranking system, we convinced skeptical citizen advisory committees to allow liberal antlerless harvests of 600-690 moose in 2004 and 2005, with the objective of halting population growth of the 16,000-17,000 moose; total harvests were 7-8% of total prehunt numbers. The resulting liberal antlerless harvests served to protect the moose population's health and habitat and to fulfill a mandate for elevated yield. Liberal antlerless harvests appear justified to halt population growth when multiyear twinning rates average ≤10% and ≥1 of the following signals substantiate low nutritional status: <50% of 36-month-old moose are parturient, average multiyear short-yearling mass is <175 kg, or >35% of annual browse biomass is removed by moose. 相似文献
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A common polygenic basis for quinine and PROP avoidance in mice 总被引:3,自引:2,他引:1
Inbred strains of mice (Mus musculus) differ greatly in ability to taste
various bitter compounds. For some compounds, the differences result from
allelic variation at a single locus. However, segregation patterns
incompatible with monogenic inheritance have been found for quinine
avoidance. The Soa bitter sensitivity locus exerts some influence on this
phenotype, but an unknown number of other loci also contribute. Relative
avoidance patterns for quinine sulfate in panels of naive inbred strains
resembled avoidance patterns for 6-n-propyl-2- thiouracil (PROP),
suggesting a common genetic basis. In particular, C57BL/6J mice strongly
avoided both 0.1 mM quinine sulfate and 1 mM PROP in two-bottle preference
tests, whereas C3H/HeJ mice were indifferent to both. Therefore, 12 BXH/Ty
recombinant inbred strains, derived from these strains, were tested with
both solutions to begin identification of the unknown bitter loci. Naive
mice were tested for four consecutive days with each compound (order
counterbalanced). Some BXH/Ty strain means resembled those of the parent
strains, but others were intermediate. This indicated recombination among
loci affecting avoidance, and therefore polygenic inheritance. The strain
means were highly correlated across compounds (r = 0.98), suggesting that
the same polygenes controlled both phenotypes. The BXH/Ty means for both
compounds were then compared with the strain genotypes at 212 chromosome
position markers distributed throughout the genome. Eight markers on five
chromosomes (3, 6, 7, 8 and 9) yielded significant correlations. Six of the
markers were correlated with both phenotypes, again suggesting common
polygenic inheritance. The marker with the highest correlation was Prp,
tightly linked to Soa on chromosome 6. The correlated marker regions likely
contain quantitative trait loci affecting bitter avoidance. The phenotypic
similarity of PROP to quinine, rather than to phenylthiourea, apparently
stemming from a common polygenic basis, indicates a difference between mice
and humans in gustatory organization related to bitters.
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Carla DB Fernandez Fernanda F Bellentani Glaura SA Fernandes Juliana E Perobelli Ana Paula A Favareto André F Nascimento Antonio C Cicogna Wilma DG Kempinas 《Reproductive biology and endocrinology : RB&E》2011,9(1):32
Background
Obesity is rapidly becoming a worldwide epidemic that affects children and adults. Some studies have shown a relationship between obesity and infertility, but until now it remains controversial. Thus, the aim of the present study was to investigate the effect of high-fat diet-induced obesity on male reproductive parameters. 相似文献10.
Whitehouse DB; Tomkins J; Lovegrove JU; Hopkinson DA; McMillan WO 《Molecular biology and evolution》1998,15(4):456-462
The expanding molecular database provides unparalleled opportunities for
characterizing genes and for studying groups of related genes. We use
sequences drawn from the database to construct an evolutionary framework
for examining the important glycolytic enzyme phosphoglucomutase (PGM).
Phosphoglucomutase plays a pivotal role in the synthesis and utilization of
glycogen and is present in all organisms. In humans, there are three
well-described isozymes, PGMI, PGM2, and PGM3. PGM1 was cloned 5 years ago;
however, repeated attempts using both immunological approaches and
molecular probes designed from PGM1 have failed to isolate either PGM2 or
PGM3. Using a phylogenetic strategy, we first identified 47 highly
divergent prokaryotic and eukaryotic PGM-like sequences from the database.
Although overall amino acid identity often fell below 20%, the relative
order, position, and sequence of three structural motifs, the active site
and the magnesium-- and sugar-binding sites, were conserved in all 47
sequences. The phylogenetic history of these sequences was complex and
marked by duplications and translocations; two instances of transkingdom
horizontal gene transfer were identified. Nonetheless, the sequences fell
within six well-defined evolutionary lineages, three of which contained
only prokaryotes. Of the two prokaryotic/eukaryotic lineages, one contained
bacterial, yeast, slimemold, invertebrate, and vertebrate homologs to human
PGM1 and the second contained likely homologs to human PGM2. Indeed, an
amino acid sequence, derived from a partial human cDNA, that fell within
the second cross-kingdom lineage bears several characteristics expected for
PGM2. A third lineage may contain homologs to human PGM3. On a general
level, our phylogenetic-based approach shows promise for the further
utilization of the extensive molecular database.
相似文献