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51.
Assessing FOXO1A as a potential susceptibility locus for type 2 diabetes and obesity in American Indians 下载免费PDF全文
52.
Hye-Kyeong Kim Mary Anne Della-Fera Dorothy B. Hausman Clifton A. Baile 《Journal of physiology and biochemistry》2010,66(3):197-203
Clenbuterol, a beta2-adrenergic receptor (β2-AR) selective agonist, has been shown to decrease body fat in animals and can induce apoptosis in adipose tissue in mice.
We hypothesized that direct actions of a β-adrenergic receptor agonist on adipocytes could trigger the observed apoptotic
effect. The hypothesis was inspected by investigating the direct effect of clenbuterol on apoptosis, adipogenesis, and lipolysis
in vitro using the 3T3-L1 cell line and rat primary adipocytes. Cells were treated with 10−9 to 10−5 M clenbuterol depending on the experiments. There was no apoptotic effect of clenbuterol both in 3T3-L1 cells and rat primary
adipocytes. Adipogenesis monitored by Oil Red O staining and AdipoRed™ assay was modestly decreased by clenbuterol treatment
(p < 0.05). In fully differentiated primary adipocytes, clenbuterol increased basal lipolysis compared with the control (p < 0.01). In summary, direct stimulation of β2-AR by clenbuterol does not cause apoptosis in adipocytes, despite a direct lipolytic stimulation and attenuation of adipogenesis. 相似文献
53.
Garret Suen Jarrod J. Scott Frank O. Aylward Sandra M. Adams Susannah G. Tringe Adrián A. Pinto-Tomás Clifton E. Foster Markus Pauly Paul J. Weimer Kerrie W. Barry Lynne A. Goodwin Pascal Bouffard Lewyn Li Jolene Osterberger Timothy T. Harkins Steven C. Slater Timothy J. Donohue Cameron R. Currie 《PLoS genetics》2010,6(9)
Herbivores can gain indirect access to recalcitrant carbon present in plant cell walls through symbiotic associations with lignocellulolytic microbes. A paradigmatic example is the leaf-cutter ant (Tribe: Attini), which uses fresh leaves to cultivate a fungus for food in specialized gardens. Using a combination of sugar composition analyses, metagenomics, and whole-genome sequencing, we reveal that the fungus garden microbiome of leaf-cutter ants is composed of a diverse community of bacteria with high plant biomass-degrading capacity. Comparison of this microbiome''s predicted carbohydrate-degrading enzyme profile with other metagenomes shows closest similarity to the bovine rumen, indicating evolutionary convergence of plant biomass degrading potential between two important herbivorous animals. Genomic and physiological characterization of two dominant bacteria in the fungus garden microbiome provides evidence of their capacity to degrade cellulose. Given the recent interest in cellulosic biofuels, understanding how large-scale and rapid plant biomass degradation occurs in a highly evolved insect herbivore is of particular relevance for bioenergy. 相似文献
54.
Bhaskar Kahali Jee‐Eun Kim Umesh Karandikar Clifton P. Bishop Ashok P. Bidwai 《Genesis (New York, N.Y. : 2000)》2010,48(1):44-55
Analysis of the retinal defects of a CK2 phosphomimetic variant of E(spl)M8 (M8S159D) and the truncated protein M8* encoded by the E(spl)D allele, suggest that the nonphosphorylated CtD “autoinhibits” repression. We have investigated this model by testing for inhibition (in “trans”) by the CtD fragment in its nonphosphorylated (M8‐CtD) and phosphomimetic (M8SD‐CtD) states. In N+ flies, ectopic M8‐CtD compromises lateral inhibition, i.e., elicits supernumerary bristles as with loss of N signaling. This antimorphic activity of M8‐CtD strongly rescues the reduced eye and/or bristle loss phenotypes that are elicited by ectopic M8SD or wild type M8. Additionally, the severely reduced eye of Nspl/Y; E(spl)D/+ flies is also rescued by M8‐CtD. Rescue is specific to the time and place, the morphogenetic furrow, where “founding” R8 photoreceptors are specified. In contrast, the phosphomimetic M8SD‐CtD that is predicted to be deficient for autoinhibition, exhibits significantly attenuated or negligible activity. These studies provide evidence that autoinhibition by the CtD regulates M8 activity in a phosphorylation‐dependent manner. genesis 48:44–55, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
55.
Radiogenic initiation of thyroid cancer: a common cellular event 总被引:2,自引:0,他引:2
R T Mulcahy M N Gould K H Clifton 《International journal of radiation biology and related studies in physics, chemistry, and medicine》1984,45(5):419-426
A transplantation system for clonogenic cells in rat thyroid was used, which allows quantitative evaluation of both the acute cytotoxicity and the late neoplastic effects of ionizing radiation at the cellular level in vivo. We have obtained direct experimental evidence that radiogenic initiation of neoplasia in vivo is a common cellular event, and that cell number influences the expression of initiation. Ten per cent of those graft sites which had received 26 clonogens surviving 5 Gy developed carcinomas, while 4 per cent of those which received 26 unirradiated clonogens developed carcinomas. By comparison, 26 per cent of the sites that were inoculated with 411 surviving irradiated clonogens developed carcinomas while none of the 38 transplant sites that received 411 unirradiated clonogens developed carcinomas. Total tumour incidence (carcinomas plus adenomas) followed the same pattern. 相似文献
56.
Speciation of Campylobacter coli, C. jejuni, C. helveticus, C. lari, C. sputorum, and C. upsaliensis by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry 下载免费PDF全文
Robert E. Mandrell Leslie A. Harden Anna Bates William G. Miller William F. Haddon Clifton K. Fagerquist 《Applied microbiology》2005,71(10):6292-6307
Multiple strains of Campylobacter coli, C. jejuni, C. helveticus, C. lari, C. sputorum, and C. upsaliensis isolated from animal, clinical, or food samples have been analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Whole bacterial cells were harvested from colonies or confluent growth on agar and transferred directly into solvent and then to a spot of dried 3-methoxy-4-hydroxycinnamic acid (matrix). Multiple ions in the 5,000- to 15,000-Da mass range were evident in spectra for each strain; one or two ions in the 9,500- to 11,000-Da range were consistently high intensity. “Species-identifying” biomarker ions (SIBIs) were evident from analyses of multiple reference strains for each of the six species, including the genome strains C. jejuni NCTC 11168 and C. jejuni RM1221. Strains grown on nine different combinations of media and atmospheres yielded SIBI masses within ±5 Da with external instrument calibration. The highest-intensity C. jejuni SIBIs were cytosolic proteins, including GroES, HU/HCj, and RplL. Multiple intraspecies SIBIs, corresponding probably to nonsynonymous nucleotide polymorphisms, also provided some intraspecies strain differentiation. MALDI-TOF MS analysis of 75 additional Campylobacter strains isolated from humans, poultry, swine, dogs, and cats revealed (i) associations of SIBI type with source, (ii) strains previously speciated incorrectly, and (iii) “strains” composed of more than one species. MALDI-TOF MS provides an accurate, sensitive, and rapid method for identification of multiple Campylobacter species relevant to public health and food safety. 相似文献
57.
C Correnti V Richardson AK Sia AD Bandaranayake M Ruiz Y Suryo Rahmanto Z Kovačević MC Clifton MA Holmes BK Kaiser J Barasch KN Raymond DR Richardson RK Strong 《PloS one》2012,7(8):e43696
Siderocalin (also lipocalin 2, NGAL or 24p3) binds iron as complexes with specific siderophores, which are low molecular weight, ferric ion-specific chelators. In innate immunity, siderocalin slows the growth of infecting bacteria by sequestering bacterial ferric siderophores. Siderocalin also binds simple catechols, which can serve as siderophores in the damaged urinary tract. Siderocalin has also been proposed to alter cellular iron trafficking, for instance, driving apoptosis through iron efflux via BOCT. An endogenous siderophore composed of gentisic acid (2,5-dihydroxybenzoic acid) substituents was proposed to mediate cellular efflux. However, binding studies reported herein contradict the proposal that gentisic acid forms high-affinity ternary complexes with siderocalin and iron, or that gentisic acid can serve as an endogenous siderophore at neutral pH. We also demonstrate that siderocalin does not induce cellular iron efflux or stimulate apoptosis, questioning the role siderocalin plays in modulating iron metabolism. 相似文献
58.
Mary Anne Della‐Fera Yang‐Ho Choi Diane L. Hartzell Juihua Duan Mark Hamrick Clifton A. Baile 《Obesity (Silver Spring, Md.)》2005,13(9):1540-1547
Objective: ob/ob mice have increased sensitivity to many of leptin's effects. The primary objective of this experiment was to determine whether ob/ob mice demonstrated increased sensitivity to leptin‐induced adipose tissue apoptosis. Research Methods and Procedures: Fifteen‐week‐old female ob/ob and Ob/? mice received 0 (saline), 2.5, or 10 μg/d leptin for 14 days through subcutaneous (sc) osmotic minipumps. Food intake (FI), body temperature, physical activity, and body weight were measured daily. Body composition and weights and adipose tissue apoptosis (percentage DNA fragmentation) of inguinal, parametrial, and retroperitoneal fat pads were determined at the end of the study. Results: FI decreases were more pronounced in ob/ob. Leptin (10 μg/d) decreased total FI 71% in ob/ob and 34% in Ob/? (p < 0.05). Body weight was decreased by both doses of leptin in ob/ob (p < 0.01) but was unchanged in Ob/?. Leptin increased body temperature in ob/ob but not in Ob/?. Physical activity was increased 400% by 10 μg/d leptin in ob/ob (p < 0.01) but decreased 13% in Ob/? (p < 0.01). Body fat content of ob/ob was reduced by both leptin doses, whereas only 10 μg/d leptin decreased body fat in Ob/?. Fat pad weights were decreased similarly by leptin in both genotypes. However, apoptosis was increased by leptin in all three fat pads in ob/ob, whereas Ob/? showed significant increases only in retroperitoneal. Discussion: ob/ob mice had greater overall sensitivity to leptin. Although ob/ob mice appeared to be more sensitive than Ob/? mice to leptin‐induced adipose tissue apoptosis, there were differences among adipose depots in responsiveness to leptin‐induced apoptosis. 相似文献
59.
Matthew C. Clifton Michael J. Simon Satchal K. Erramilli Huide Zhang Jelena Zaitseva Mark A. Hermodson Cynthia V. Stauffacher 《The Journal of biological chemistry》2015,290(9):5555-5565
Bacterial ATP-binding cassette (ABC) importers are primary active transporters that are critical for nutrient uptake. Based on structural and functional studies, ABC importers can be divided into two distinct classes, type I and type II. Type I importers follow a strict alternating access mechanism that is driven by the presence of the substrate. Type II importers accept substrates in a nucleotide-free state, with hydrolysis driving an inward facing conformation. The ribose transporter in Escherichia coli is a tripartite complex consisting of a cytoplasmic ATP-binding cassette protein, RbsA, with fused nucleotide binding domains; a transmembrane domain homodimer, RbsC2; and a periplasmic substrate binding protein, RbsB. To investigate the transport mechanism of the complex RbsABC2, we probed intersubunit interactions by varying the presence of the substrate ribose and the hydrolysis cofactors, ATP/ADP and Mg2+. We were able to purify a full complex, RbsABC2, in the presence of stable, transition state mimics (ATP, Mg2+, and VO4); a RbsAC complex in the presence of ADP and Mg2+; and a heretofore unobserved RbsBC complex in the absence of cofactors. The presence of excess ribose also destabilized complex formation between RbsB and RbsC. These observations suggest that RbsABC2 shares functional traits with both type I and type II importers, as well as possessing unique features, and employs a distinct mechanism relative to other ABC transporters. 相似文献
60.
Thomas E Edwards Ariel B Abramov Eric R Smith Ruth O Baydo Jess T Leonard David J Leibly Kaitlin B Thompkins Matthew C Clifton Anna S Gardberg Bart L Staker Wesley C Van Voorhis Peter J Myler Lance J Stewart 《BMC structural biology》2011,11(1):1-9