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161.
162.
163.
Mervyn Beukes Yolandy Lemmer Madrey Deysel Juma’a R. Al Dulayymi Mark S. Baird Gani Koza Maximiliano M. Iglesias Richard R. Rowles Cornelia Theunissen Johan Grooten Gianna Toschi Vanessa V. Roberts Lynne Pilcher Sandra Van Wyngaardt Nsovo Mathebula Mohammed Balogun Anton C. Stoltz Jan A. Verschoor 《Chemistry and physics of lipids》2011,(2):175
164.
Summary Tench (Tinca tinca) were acclimated to either aerated (P
O
2 17.6 KPa) or hypoxic (P
O
2 1.5 KPa) water for 6 weeks.Acclimation to hypoxia resulted in a decrease in mitochondrial volume fraction in both slow (22.9 to 15.0 %) and fast glycolytic (4.5 to 1.8 %) myotomal muscles fibres (P<0.01).Intermyofibrillar mitochondrial populations (4.4 to 1.2% slow; 0.6 to 0.04% fast fibres) were affected to a greater extent than those in the subsarcolemmal zone (18.5 to 13.8% slow; 3.9 to 1.8% fast fibres). After acclimation to hypoxia, cytochrome-oxidase activities decreased by 31 and 33 % in slow and fast fibres, respectively, but were maintained in the liver.Fibre size remained unchanged and actively differentiating fibres were observed in muscles from both groups of fish. Hypoxia resulted in a significant increase in myofibrillar volume fraction in both slow (43.1 to 56.1 %) and fast glycolytic fibres (73.1 to 82.7%) (P<0.05).Glycogen concentrations (mg/100g tissue) for liver (6616) slow muscle (1892) and fast muscle (334) were similar for fish acclimated to aerated or hypoxic water. Acclimation to hypoxia increased carnitine palmitoyl transferase activity (moles substrate utilised g·dry wt-1 min-1) in slow (0.42 to 1.1), fast glycolytic muscle (<0.01 to 0.15) and liver (1.1 to 3.7) indicating an enhanced capacity for fatty acid oxidation.Phosphofructokinase activities of fast glycolytic fibres were similar in fish acclimated to either aerated or hypoxic water, consistent with an unaltered capacity for anaerobic glycogenolysis. Hexokinase activities (moles substate utilised, g·dry wt-1 min-1) decreased in fast fibres (1.2 to 0.4) but were maintained in the slow muslce (2.1 to 2.5) and liver (4.5 to 4.8) of hypoxic fish. The activities of phosphofructokinase in slow muscle and phosphofructokinase, pyruvate kinase and lactate dehydrogenase in liver were two times higher in fish acclimated to hypoxia. An enhanced capacity for glycolysis in these tissues may reflect a reduced threshold for anaerobic metabolism during activity and/or an adaptation for acute exposure to anoxia in fish acclimated to hypoxia.Abbreviations/Glossary CO
cytochrome oxidase activity
- CPT
carnitine palmitoyltransferase activity
- HK
hexokinase activity
- LDH
lactate dehydrogenase activity
- PFK
phosphofructokinase activity
- PK
pyruvate kinase activity
- Vv
volume fractions of cell components
- normoxic
fish acclimated to aerated water
- hypoxic
fish acclimated to reduced oxygen tensions
-
P
O
2
partial pressure of oxygen tension
A preliminary account of part of this work was presented at theXth European Meeting on Muscle and Cell Motility held at Galway, Ireland, in September 1981 相似文献
165.
Albright CL Steffen AD Wilkens LR Henderson BE Kolonel LN 《Obesity (Silver Spring, Md.)》2008,16(5):1138-1143
Objective: To determine whether the prevalence of obesity in ethnic admixture adults varies systematically from the average of the prevalence estimates for the ethnic groups with whom they share a common ethnicity. Methods and Procedures: The sample included 215,000 adults who reported one or more ethnicities, height, weight, and other characteristics through a mailed survey. Results: The highest age‐adjusted prevalence of overweight (BMI ≥ 25) was in Hawaiian/Latino men (88%; n = 41) and black/Latina women (74.5%; n = 79), and highest obesity (BMI ≥ 30) rates were in Hawaiian/Latino men (53.7%; n = 41) and Hawaiian women (39.2%, n = 1,247). The prevalence estimates for most admixed groups were similar to or higher than the average of the prevalences for the ethnic groups with whom they shared common ethnicities. For instance, the prevalence of overweight/obesity in five ethnic admixtures—Asian/white, Hawaiian/white, Hawaiian/Asian, Latina/white, and Hawaiian/Asian/white ethnic admixtures—was significantly higher (P < 0.0001) than the average of the prevalence estimates for their component ethnic groups. Discussion: The identification of individuals who have a high‐risk ethnic admixture is important not only to the personal health and well‐being of such individuals, but could also be important to future efforts in order to control the epidemic of obesity in the United States. 相似文献
166.
Steven H. D. Haddock Nadia Mastroianni Lynne M. Christianson 《Proceedings. Biological sciences / The Royal Society》2010,277(1685):1155-1160
Genes for the family of green-fluorescent proteins (GFPs) have been found in more than 100 species of animals, with some species containing six or more copies producing a variety of colours. Thus far, however, these species have all been within three phyla: Cnidaria, Arthropoda and Chordata. We have discovered GFP-type fluorescent proteins in the phylum Ctenophora, the comb jellies. The ctenophore proteins share the xYG chromophore motif of all other characterized GFP-type proteins. These proteins exhibit the uncommon property of reversible photoactivation, in which fluorescent emission becomes brighter upon exposure to light, then gradually decays to a non-fluorescent state. In addition to providing potentially useful optical probes with novel properties, finding a fluorescent protein in one of the earliest diverging metazoans adds further support to the possibility that these genes are likely to occur throughout animals. 相似文献
167.
Meredith E. Jackrel Roberto Valverde Lynne Regan 《Protein science : a publication of the Protein Society》2009,18(4):762-774
The design of protein–peptide interactions has a wide array of practical applications and also reveals insight into the basis for molecular recognition. Here, we present the redesign of a tetratricopeptide repeat (TPR) protein scaffold, along with its corresponding peptide ligand. We show that the binding properties of these protein–peptide pairs can be understood, quantitatively, using straightforward chemical considerations. The recognition pairs we have developed are also practically useful for the specific identification of tagged proteins. We demonstrate the facile replacement of these proteins, which we have termed T‐Mods (TPR‐based recognition module), for antibodies in both detection and purification applications. The new protein–peptide pair has a dissociation constant that is weaker than typical antibody–antigen interactions, yet the recognition pair is highly specific and we have shown that this affinity is sufficient for both Western blotting and affinity purification. Moreover, we demonstrate that this more moderate affinity is actually advantageous for purification applications, because extremely harsh conditions are not required to dissociate the T‐Mod‐peptide interaction. The results we present are important, not only because they represent a successful application of protein design but also because they help define the properties that should be sought in other scaffolds that are being developed as antibody replacements. 相似文献
168.
Latha Ramdas Kevin R Coombes Keith Baggerly Lynne Abruzzo W Edward Highsmith Tammy Krogmann Stanley R Hamilton Wei Zhang 《Genome biology》2001,2(11):research0047.1-research00477
Background
A key assumption in the analysis of microarray data is that the quantified signal intensities are linearly related to the expression levels of the corresponding genes. To test this assumption, we experimentally examined the relationship between signal and expression for the two types of microarrays we most commonly encounter: radioactively labeled cDNAs on nylon membranes and fluorescently labeled cDNAs on glass slides. 相似文献169.
Nick R Love Yaoyao Chen Boyan Bonev Michael J Gilchrist Lynne Fairclough Robert Lea Timothy J Mohun Roberto Paredes Leo AH Zeef Enrique Amaya 《BMC developmental biology》2011,11(1):1-15
Background
During liver development, intrahepatic bile ducts are thought to arise by a unique asymmetric mode of cholangiocyte tubulogenesis characterized by a series of remodeling stages. Moreover, in liver diseases, cells lining the Canals of Hering can proliferate and generate new hepatic tissue. The aim of this study was to develop protocols for three-dimensional visualization of protein expression, hepatic portal structures and human hepatic cholangiocyte tubulogenesis.Results
Protocols were developed to digitally visualize portal vessel branching and protein expression of hepatic cell lineage and extracellular matrix deposition markers in three dimensions. Samples from human prenatal livers ranging from 7 weeks + 2 days to 15½ weeks post conception as well as adult normal and acetaminophen intoxicated liver were used. The markers included cytokeratins (CK) 7 and 19, the epithelial cell adhesion molecule (EpCAM), hepatocyte paraffin 1 (HepPar1), sex determining region Y (SRY)-box 9 (SOX9), laminin, nestin, and aquaporin 1 (AQP1). Digital three-dimensional reconstructions using CK19 as a single marker protein disclosed a fine network of CK19 positive cells in the biliary tree in normal liver and in the extensive ductular reactions originating from intrahepatic bile ducts and branching into the parenchyma of the acetaminophen intoxicated liver. In the developing human liver, three-dimensional reconstructions using multiple marker proteins confirmed that the human intrahepatic biliary tree forms through several developmental stages involving an initial transition of primitive hepatocytes into cholangiocytes shaping the ductal plate followed by a process of maturation and remodeling where the intrahepatic biliary tree develops through an asymmetrical form of cholangiocyte tubulogenesis.Conclusions
The developed protocols provide a novel and sophisticated three-dimensional visualization of vessels and protein expression in human liver during development and disease. 相似文献170.
John A. Bunce Lynne A. Isbell Mark N. Grote Gerald H. Jacobs 《International journal of primatology》2011,32(5):1058-1075
The selective advantages to primates of trichromatic color vision, allowing discrimination among the colors green, yellow,
orange, and red, remain poorly understood. We test the hypothesis that, for primates, an advantage of trichromacy over dichromacy,
in which such colors are apt to be confused, lies in the detection of yellow, orange, or red (YOR) food patches at a distance,
while controlling for the potentially confounding influences of reproductive status and memory of food patch locations. We
employ socially monogamous titi monkeys (Callicebus brunneus) which, like most platyrrhine primates, have polymorphic color vision resulting in populations containing both dichromatic
and trichromatic individuals. Wild Callicebus brunneus spent most foraging time in YOR food patches, the locations of most of which were likely to have been memorable for the subjects.
Overall, both dichromatic and trichromatic females had significantly higher encounter rates than their dichromatic male pair
mates for low-yield ephemeral YOR food patches whose locations were less likely to have been remembered. We detected no difference
in the encounter rates of dichromatic and trichromatic females for such patches. However, the data suggest that such a difference
may be detectable with a larger sample of groups of Callicebus brunneus, a larger sample of foraging observations per group, or both. We propose that a trichromatic advantage for foraging primates
may be realized only when individuals’ energy requirements warrant searching for nonmemorable YOR food patches, a context
for selection considerably more limited than is often assumed in explanations of the evolution of primate color vision. 相似文献