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41.
Health organizations worldwide recommend that adults and children minimize intakes of excess energy and salty, sweet, and fatty foods (all of which are highly preferred tastes) and eat diets richer in whole grains, low- and non- fat dairy products, legumes, fish, lean meat, fruits, and vegetables (many of which taste bitter). Despite such recommendations and the well-established benefits of these foods to human health, adults are not complying, nor are their children. A primary reason for this difficulty is... 相似文献
42.
Boot EP Koning GA Storm G Wagenaar-Hilbers JP van Eden W Everse LA Wauben MH 《Arthritis research & therapy》2005,7(3):R604-R615
T cells have an important role during the development of autoimmune diseases. In adjuvant arthritis, a model for rheumatoid
arthritis, we found that the percentage of CD4+ T cells expressing the activation marker CD134 (OX40 antigen) was elevated before disease onset. Moreover, these CD134+ T cells showed a specific proliferative response to the disease-associated epitope of mycobacterial heat shock protein 60,
indicating that this subset contains auto-aggressive T cells. We studied the usefulness of CD134 as a molecular target for
immune intervention in arthritis by using liposomes coated with a CD134-directed monoclonal antibody as a drug targeting system.
Injection of anti-CD134 liposomes subcutaneously in the hind paws of pre-arthritic rats resulted in targeting of the majority
of CD4+CD134+ T cells in the popliteal lymph nodes. Furthermore, we showed that anti-CD134 liposomes bound to activated T cells were not
internalized. However, drug delivery by these liposomes could be established by loading anti-CD134 liposomes with the dipalmitate-derivatized
cytostatic agent 5'-fluorodeoxyuridine. These liposomes specifically inhibited the proliferation of activated CD134+ T cells in vitro, and treatment with anti-CD134 liposomes containing 5'-fluorodeoxyuridine resulted in the amelioration of adjuvant arthritis.
Thus, CD134 can be used as a marker for auto-aggressive CD4+ T cells early in arthritis, and specific liposomal targeting of drugs to these cells via CD134 can be employed to downregulate
disease development. 相似文献
43.
Pandinus imperator scorpion venom blocks voltage-gated potassium channels in GH3 cells 总被引:1,自引:1,他引:0
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We examined the effects of Pandinus imperator scorpion venom on voltage-gated potassium channels in cultured clonal rat anterior pituitary cells (GH3 cells) using the gigohm-seal voltage-clamp method in the whole-cell configuration. We found that Pandinus venom blocks the voltage-gated potassium channels of GH3 cells in a voltage-dependent and dose-dependent manner. Crude venom in concentrations of 50-500 micrograms/ml produced 50-70% block of potassium currents measured at -20 mV, compared with 25-60% block measured at +50 mV. The venom both decreased the peak potassium current and shifted the voltage dependence of potassium current activation to more positive potentials. Pandinus venom affected potassium channel kinetics by slowing channel opening, speeding deactivation slightly, and increasing inactivation rates. Potassium currents in cells exposed to Pandinus venom did not recover control amplitudes or kinetics even after 20-40 min of washing with venom-free solution. The concentration dependence of crude venom block indicates that the toxins it contains are effective in the nanomolar range of concentrations. The effects of Pandinus venom were mimicked by zinc at concentrations less than or equal to 0.2 mM. Block of potassium current by zinc was voltage dependent and resembled Pandinus venom block, except that block by zinc was rapidly reversible. Since zinc is found in crude Pandinus venom, it could be important in the interaction of the venom with the potassium channel. We conclude that Pandinus venom contains toxins that bind tightly to voltage-dependent potassium channels in GH3 cells. Because of its high affinity for voltage-gated potassium channels and its irreversibility, Pandinus venom may be useful in the isolation, mapping, and characterization of voltage-gated potassium channels. 相似文献
44.
Howe GT; Bucciaglia PA; Hackett WP; Furnier GR; Cordonnier-Pratt MM; Gardner G 《Molecular biology and evolution》1998,15(2):160-175
The phytochrome photoreceptors play important roles in the photoperiodic
control of vegetative bud set, growth cessation, dormancy induction, and
cold-hardiness in trees. Interestingly, ecotypic differences in
photoperiodic responses are observed in many temperate- zone tree species.
Northern and southern ecotypes of black cottonwood (Populus trichocarpa
Torr. & Gray), for example, exhibit marked differences in the timing of
short-day-induced bud set and growth cessation, and these responses are
controlled by phytochrome. Therefore, as a first step toward determining
the molecular genetic basis of photoperiodic ecotypes in trees, we
characterized the phytochrome gene (PHY) family in black cottonwood. We
recovered fragments of one PHYA and two PHYB using PCR-based cloning and by
screening a genomic library. Results from Southern analyses confirmed that
black cottonwood has one PHYA locus and two PHYB loci, which we arbitrarily
designated PHYB1 and PHYB2. Phylogenetic analyses which included PHY from
black cottonwood, Arabidopsis thaliana and tomato (Solanum lycopersicum)
suggest that the PHYB/D duplications in these species occurred
independently. When Southern blots were probed with PHYC, PHYE, and PHYE
heterologous probes, the strongest bands that we detected were those of
black cottonwood PHYA and/or PHYB. These results suggest that black
cottonwood lacks members of the PHYC/F and PHYE subfamilies. Although black
cottonwood could contain additional PHY that are distantly related to known
angiosperm PHY, our results imply that the PHY family of black cottonwood
is less complex than that of other well-characterized dicot species such as
Arabidopsis and tomato. Based on Southern analyses of five black cottonwood
genotypes representing three photoperiodic ecotypes, substantial
polymorphism was detected for at least one of the PHYB loci but not for the
PHYA locus. The novel character of the PHY family in black cottonwood, as
well as the differences in polymorphism we observed between the PHYA and
PHYB subfamilies, indicates that a number of fundamental macro- and
microevolutionary questions remain to be answered about the PHY family in
dicots.
相似文献
45.
Iron salts and transferrin are specifically required for cell division of cultured 3T6 cells. 总被引:5,自引:0,他引:5
P S Rudland H Durbin D Clingan L J de Asua 《Biochemical and biophysical research communications》1977,75(3):556-562
3T6 Swiss mouse fibroblasts can be plated in medium without serum. Prostaglandin F2∞, fibroblastic growth factor, epidermal growth factor and insulin stimulate DNA synthesis in medium containing vitamin B12. A combination of these factors, however, does not stimulate cell division under our conditions. Iron salts and transferrin or low concentrations of serum are required to be concurrently present with the growth factors before cell division is observed. 相似文献
46.
J E Lever D Clingan L J de Asua 《Biochemical and biophysical research communications》1976,71(1):136-143
The (Na+, K+)ATPase transport system in resting 3T3 Swiss mouse fibroblasts is rapidly activated by prostaglandin F2α and insulin, which initiate DNA synthesis in these cells. Prostaglandin F2α, but not insulin, promotes a rapid increase in Pi uptake which is partially coupled to the Na+ pump. This rapid activation of both transport systems occurs by a mechanism which does not require fluctuation of cyclic AMP levels or new protein synthesis. A subsequent protein synthesis-dependent increase in Pi uptake is stimulated by insulin and prostaglandin F2α. These results suggest that different types of control of membrane transport occur during growth stimulation. 相似文献
47.
Benjamin Groves Hilde Abrahamsen Heather Clingan Michael Frantz Lauren Mavor Jeffrey Bailey Dzwokai Ma 《PloS one》2010,5(1)
Macroautophagy is a cellular process whereby the cell sequesters and recycles cytosolic constituents in a lysosome-dependent manner. It has also been implicated in a number of disorders, including cancer and neurodegeneration. Although a previous report that AGS3 over-expression promotes macroautophagy suggests a stimulatory role of AGS3 in this process, we have found that knock-down of AGS3, unexpectedly, also induces macroautophagy, indicating an inhibitory function of endogenous AGS3 in macroautophagy. Interestingly, AGS3 phosphorylation is decreased upon induction of mammalian target of rapamycin (mTOR)-dependent macroautophagy. Moreover, unlike wild-type AGS3, over-expression of an AGS3 mutant lacking this modification fails to enhance macroautophagic activity. These observations imply that AGS3 phosphorylation may participate in the modulation of macroautophagy. 相似文献
48.
PAÚL M. VELAZCO ALFRED L. GARDNER BRUCE D. PATTERSON 《Zoological Journal of the Linnean Society》2010,159(3):785-812
Platyrrhinus is a diverse genus of small to large phyllostomid bats characterized by a comparatively narrow uropatagium thickly fringed with hair, a white dorsal stripe, comparatively large inner upper incisors that are convergent at the tips, and three upper and three lower molars. Eighteen species are currently recognized, the majority occurring in the Andes. Molecular, morphological, and morphometric analyses of specimens formerly identified as Platyrrhinus helleri support recognition of Platyrrhinus incarum as a separate species and reveal the presence of two species from western and northern South America that we describe herein as new ( Platyrrhinus angustirostris sp. nov. from eastern Colombia and Ecuador, north‐eastern Peru, and Venezuela and Platyrrhinus fusciventris sp. nov. from Guyana, Suriname, French Guiana, Trinidad and Tobago, northern Brazil, eastern Ecuador, and southern Venezuela). These two new species are sister taxa and, in turn, sister to Platyrrhinus incarum. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 159 , 785–812. 相似文献
49.
Forty crossbred barrows (Camborough 15 Line female×Canabred sire) weighing an average of 79.6±8.0?kg were used in a factorial design experiment (5 barleys×2 enzyme levels) conducted to determine the effects of phytase supplementation on nutrient digestibility in low-phytate barleys fed to finishing pigs. The pigs were assigned to one of 10 dietary treatments comprised of a normal 2-rowed, hulled variety of barley (CDC Fleet, 0.26% phytate) or 2 low-phytate hulled genotypes designated as LP422 (0.14% phytate) and LP635 (0.09% phytate). A normal, hulless barley (CDC Dawn, 0.26% phytate) and a hulless genotype designated as LP422H (0.14% phytate) were also included. All barleys were fed with and without phytase (Natuphos 5000 FTU/kg). The diets fed contained 98% barley, 0.5% vitamin premix, 0.5% trace mineral premix, 0.5% NaCl and 0.5% chromic oxide but no supplemental phosphorus. The marked feed was provided for a 7-day acclimatization period, followed by a 3-day faecal collection. In the absence of phytase, phosphorus digestibility increased substantially (P<0.05) as the level of phytate in the barley declined. For the hulled varieties, phosphorus digestibility increased from 12.9% for the normal barley (0.26% phytate) to 35.3 and 39.8% for the two low-phytate genotypes (0.14 and 0.09% phytate respectively). For the hulless varieties, phosphorus digestibility increased from 9.2% for the normal barley (0.26% phytate) to 34.7% for the hulless variety with 54% of the normal level of phytate (0.14% phytate). In contrast, when phytase was added to the diet, there was little difference in phosphorus digestibility between pigs fed normal barley and those fed the low-phytate genotypes (significant barley×enzyme interaction, P=0.01). For the hulled varieties, phosphorus digestibility was 50.1% for the barley with the normal level of phytate (0.26% phytate) compared with 51.1 and 52.4% for the varieties with 54 and 35% of the normal level of phytate (0.14 and 0.09% phytate respectively). For the hulless varieties, phosphorus digestibility increased from 47.1% for the normal barley (0.26% phytate) to 54.4% for the hulless variety with 54% of the normal level of phytate (0.14% phytate). In conclusion, both supplementation with phytase and selection for low-phytate genotypes of barley were successful in increasing the digestibility of phosphorus for pigs. Unfortunately, the effects did not appear to be additive. Whether or not swine producers will choose low-phytate barley or supplementation with phytase as a means to improve phosphorus utilization, will likely depend on the yield potential of low-phytate barley and the additional costs associated with supplementation with phytase. 相似文献
50.