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71.
Helen L. Jessop Raquel Demarco de Hormaeche Kathryn E. Senior Paul Tonks 《FEMS microbiology letters》1988,55(2):207-212
Abstract Depending on the culture conditions, Pyrodictium occultum cells revealed two different types of fibers with significant differences in their width in the electron microscope. During growth on elemental sulfur preferentially fibres with a diameter of about 23 nm (type I) were produced. When elemental sulfur was substituted by thiosulfate fibers with a diameter of around 15 nm (type II), were the main appendages. Both types form hollow cylinders consisting of helically arranged sub-units with a wall thickness of 2–3 nm. A triple- layered unit membrane could not be found. 相似文献
72.
José Manuel Fernández-Ábalos Helen Fox Chris Pitt Brian Wells & John H. Doonan 《Molecular microbiology》1998,27(1):121-130
Green fluorescent protein (GFP) is a useful reporter to follow the in vivo behaviour of proteins, but the wild-type gfp gene does not function in many organisms, including many plants and filamentous fungi. We show that codon-modified forms of gfp , produced for use in plants, function effectively in Aspergillus nidulans both as gene expression reporters and as vital reporters for protein location. To demonstrate the use of these modified gfp s as reporter genes we have used fluorescence to follow ethanol-induced GFP expression from the alcA promoter. Translational fusions with the modified gfp were used to follow protein location in living cells; plant ER-retention signals targeted GFP to the endoplasmic reticulum, whereas fusion to the GAL4 DNA-binding domain targeted it to the nucleus. Nuclear-targeted GFP allowed real-time observation of nuclear movement and division. These modified gfp genes should provide useful markers to follow gene expression, organelle behaviour and protein trafficking in real time. 相似文献
73.
Myles S Faith Kathleen L Keller Patty Matz Susan L Johnson Rebecca Lewis Marie Alexandra Jorge Clare Ridley Helen Han Shoshanna Must Moonseong Heo Angelo Pietrobelli Steven B Heymsfield David B Allison 《Twin research》2002,5(5):472-475
"Project Grow-2-Gether" is a child nutrition study of same-sex, 3- to 7-year-old monozygotic and dizygotic twin pairs. The study attempts to bridge two bodies of literature that have rarely interfaced with respect to obesity and ingestive behavior: the first being behavioral genetic approaches to obesity-related traits, and the second being developmental approaches focusing on parent-child relationships. The overarching aim of Project Grow-2-Gether is to disentangle genetic from potential home-environmental influences on child eating behavior and body fat. This paper reviews the rationale for Project Grow-2-Gether, its procedures, and core phenotypic measurement battery. A focus of the study is acquisition of controlled food intake measurements obtained in the laboratory, measurement of specific home environmental variables, and multi-method evaluation of parent-child feeding relations. Future directions may involve longitudinal assessment of child growth and molecular analyses for specific genes that influence child eating behavior. 相似文献
74.
Walther TC Pickersgill HS Cordes VC Goldberg MW Allen TD Mattaj IW Fornerod M 《The Journal of cell biology》2002,157(1):63-77
Oxysterol binding proteins (OSBPs) comprise a large conserved family of proteins in eukaryotes. Their ubiquity notwithstanding, the functional activities of these proteins remain unknown. Kes1p, one of seven members of the yeast OSBP family, negatively regulates Golgi complex secretory functions that are dependent on the action of the major yeast phosphatidylinositol/phosphatidylcholine Sec14p. We now demonstrate that Kes1p is a peripheral membrane protein of the yeast Golgi complex, that localization to the Golgi complex is required for Kes1p function in vivo, and that targeting of Kes1p to the Golgi complex requires binding to a phosphoinositide pool generated via the action of the Pik1p, but not the Stt4p, PtdIns 4-kinase. Localization of Kes1p to yeast Golgi region also requires function of a conserved motif found in all members of the OSBP family. Finally, we present evidence to suggest that Kes1p may regulate adenosine diphosphate-ribosylation factor (ARF) function in yeast, and that it may be through altered regulation of ARF that Kes1p interfaces with Sec14p in controlling Golgi region secretory function. 相似文献
75.
Miampamba M Germano PM Arli S Wong HH Scott D Taché Y Pisegna JR 《Regulatory peptides》2002,105(3):145-154
Pituitary adenylate cyclase-activating polypeptide (PACAP) is known to regulate gastric acid secretion and intestinal motility. In the present study, the pattern of distribution of PACAP and PACAP type 1 receptor (PAC1) immunoreactivities were examined in the rat stomach and distal colon using a specific polyclonal antibody raised against rat/human PAC1. Western blot of the membrane preparations of NIH/3T3 cells transfected with the human PAC1 obtained by using rabbit polyclonal anti-PAC1 antibody showed a protein band with a molecular mass of approximately 50 kDa. NIH/3T3 cells transfected with the human PAC1 and incubated with the anti-PAC1 antibody displayed surface cell-type immunoreactivity, which was internalized following ligand exposure. In gastric or colonic longitudinal muscle/myenteric plexus (LMMP) whole mount preparations as well as cryostat sections, PACAP immunoreactivity was observed in cell bodies within the myenteric ganglia and nerve fibers in the muscle layers and mucosa. PAC1 immunoreactivity was confined mainly on the surface of the nerve cells. PACAP and PAC1 immunoreactivities showed a similar pattern of distribution in gastric and colonic tissues. Adjacent sections or LMMP whole mount preparations labeled with protein gene product 9.5 (PGP 9.5) revealed the neuronal identity of myenteric cells bearing PAC1. The neuronal localization of PACAP and PAC1 receptors supports their role in the neural regulation of gastric acid secretion and gastrointestinal motor function. 相似文献
76.
Tallgrass prairie is among the most endangered ecosystems in North America. High‐diversity restorations protect remnant habitat and expand native communities. Excluding land acquisition, the most expensive step in restoration is procuring seed. Given this cost, managers want to maximize seedling establishment. Native species that flower and ripen early in the growing season are included in a diverse seeding mix but as a group they have not successfully established. For early‐maturing species, the practice of storing seeds in a cold room from harvest until sowing in the dormant season effectively eliminates exposure to the summer conditions seeds would naturally have in the wild. In this study, we compared the effect of summer sowing timing and winter sowing timing on establishment in field conditions. In August 2004 and December 2004, we broadcast a seed mix of seven early‐maturing species: Antennaria plantaginifolia (L.) Richardson. (Pussy toes), Arabis lyrata L. (Sand cress), Carex swanii (Fernald) Mack. (Downy green sedge), Hymenopappus scabiosaeus L'Hér. (Old plainsman), Lupinus perennis L. ssp. perennis var. occidentalis S. Watson. (Wild lupine), Phlox bifida Beck. (Sand phlox) and Hesperostipa spartea (Trin.) Barkworth. (Porcupine grass). We collected data on establishment and reproductive success at 12 time points from June 2005 until October 2008. Species established one growing season sooner when planted at the summer sowing time, and diversity in the summer sowing plots was higher after 4 years. Quicker establishment may have benefits such as providing early competition from weeds that may outweigh additional effort required to ensure timely planting. 相似文献
77.
Summary In analysis of longitudinal data, it is not uncommon that observation times of repeated measurements are subject‐specific and correlated with underlying longitudinal outcomes. Taking account of the dependence between observation times and longitudinal outcomes is critical under these situations to assure the validity of statistical inference. In this article, we propose a flexible joint model for longitudinal data analysis in the presence of informative observation times. In particular, the new procedure considers the shared random‐effect model and assumes a time‐varying coefficient for the latent variable, allowing a flexible way of modeling longitudinal outcomes while adjusting their association with observation times. Estimating equations are developed for parameter estimation. We show that the resulting estimators are consistent and asymptotically normal, with variance–covariance matrix that has a closed form and can be consistently estimated by the usual plug‐in method. One additional advantage of the procedure is that it provides a unified framework to test whether the effect of the latent variable is zero, constant, or time‐varying. Simulation studies show that the proposed approach is appropriate for practical use. An application to a bladder cancer data is also given to illustrate the methodology. 相似文献
78.
Eley HL Russell ST Baxter JH Mukerji P Tisdale MJ 《American journal of physiology. Endocrinology and metabolism》2007,293(4):E923-E931
To investigate the mechanism by which beta-hydroxy-beta-methylbutyrate (HMB) attenuates the depression of protein synthesis in the skeletal muscle of cachectic mice, a study has been carried out in murine myotubes in the presence of proteolysis-inducing factor (PIF). PIF inhibited protein synthesis by 50% within 4 h, and this was effectively attenuated by HMB (25-50 muM). HMB (50 muM) alone stimulated protein synthesis, and this was attenuated by rapamycin (27 nM), an inhibitor of mammalian target of rapamycin (mTOR). Further evidence for an involvement of this pathway was shown by an increased phosphorylation of mTOR, the 70-kDa ribosomal S6 kinase (p70(S6k)), and initiation factor 4E-binding protein (4E-BP1) and an increased association of eukaryotic initiation factor 2 (eIF4E) with eIF4G. PIF alone induced a transient (1-2 h) stimulation of phosphorylation of mTOR and p70(S6k). However, in the presence of HMB, phosphorylation of mTOR, p70(S6k), and 4E-BP1 was increased, and inactive 4E-BP1-eIF4E complex was reduced, whereas the active eIF4G.eIF4E complex was increased, suggesting continual stimulation of protein synthesis. HMB alone reduced phosphorylation of elongation factor 2, but this effect was not seen in the presence of PIF. PIF induced autophosphorylation of the double-strand RNA-dependent protein kinase (PKR), leading to phosphorylation of eIF2 on the alpha-subunit, which would inhibit protein synthesis. However, in the presence of HMB, phosphorylation of PKR and eIF2alpha was attenuated, and this was also observed in skeletal muscle of cachectic mice administered HMB (0.25 g/kg). These results suggest that HMB attenuates the depression of protein synthesis by PIF in myotubes through multiple mechanisms. 相似文献
79.
Background
It is widely accepted that orthologous genes between species are conserved at the sequence level and perform similar functions in different organisms. However, the level of conservation of gene expression patterns of the orthologous genes in different species has been unclear. To address the issue, we compared gene expression of orthologous genes based on 2,557 human and 1,267 mouse samples with high quality gene expression data, selected from experiments stored in the public microarray repository ArrayExpress. 相似文献80.
Helen Kopnina 《Dialectical Anthropology》2007,31(4):363-381
Anthropologists are known to work in contexts wider than academic settings, actively engaging with people from other disciplines
and professions. The lecturers in the Fashion Institute where we presently work are challenged to integrate the practical
knowledge and skills originating from the fashion industry into lessons, lectures and␣projects that prepare the students for
their future careers. Our own task as (anthro)pology lecturers in Intercultural Communication and Culture and Globalization
courses is to engrain a broader knowledge to compliment the practical competencies required in the professional settings.
An example of the practical assignments is integrating the students' knowledge of minority groups or other cultures in developing
certain fashion brands that would appeal to different ethnic groups or social classes within society or be marketable abroad.
The deeper knowledge of segmentation, niche markets and specific target groups helps students to orient themselves in professional
situations within the fashion industry. This requires an act of translation as well as transformation in order to translate
the general (such as cultural theories) into the concrete (such as examples from the fashion industry) and to transform concrete
examples and cases into broader theories. This article reflects on such acts of translation and transformation as evidenced
in fashion magazines such as Vogue. 相似文献