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81.
Floyd Matthew Mizuyama Masaru Obuchi Masami Sommer Brigitte Miller Mark GR Kawamura Iori Kise Hiroki Reimer James D. Beger Maria 《Coral reefs (Online)》2020,39(5):1361-1376
Coral Reefs - Global warming is leading to range shifts of marine species, threatening the structure and functioning of ecological communities and human populations that rely on them. The largest... 相似文献
82.
GR Hunt 《New Zealand journal of zoology.》2013,40(1):68-76
Woodpeckers and certain passerine species secure encased food in the environment in various ways to facilitate the extraction of the contents with their bills. They do this by securing the food items in locations such as crevices and holes, newly defined in this paper as ‘vice-anvils’. Here I report that free-living New Caledonian crows (Corvus moneduloides) and rooks (Corvus frugilegus, in New Zealand) also use vice-anvils to process candlenuts and walnuts, respectively. New Caledonian crows placed candlenut sections in vice-anvils to aid kernel extraction, after the candlenuts had been dropped onto an anvil to break them open. In contrast, rooks used vice-anvils to secure walnuts while they broke the shell with their bills. Long-term use by rooks of a vice-anvil in a tree had produced a ‘purpose-made’ nut-cracking site. My findings extend the persistent use of specific vice-anvils to Corvus species and further demonstrate their innovative and flexible foraging behaviour. 相似文献
83.
Phylogenetic relationships among prokaryotic and eukaryotic catalases 总被引:13,自引:1,他引:12
Seventy-four catalase protein sequences, including 29 bacterial, 8 fungal,
7 animal, and 30 plant sequences, were compiled, and 70 were used for
phylogenetic reconstruction. The core of the resulting tree revealed
unique, separate groups of plant and animal catalases, two groups of fungal
catalases, and three groups of bacterial catalases. The only overlap of
kingdoms occurred within one branch and involved fungal and bacterial
large-subunit enzymes. The other fungal branch was closely linked to the
group of animal enzymes. Group I bacterial catalases were more closely
related to the plant enzymes and contained such diverse taxa as the
Gram-positive Listeria seeligeri, Deinocococcus radiodurans, and
gamma-proteobacteria. Group III bacterial sequences were more closely
related to fungal and animal sequences and included enzymes from a broad
range of bacteria including high- and low-GC Gram positives,
proteobacteria, and a bacteroides species. Group II was composed of
large-subunit catalases from diverse sources including Gram positives
(low-GC Bacilli and high-GC Mycobacteria), proteobacteria, and species of
the filamentous fungus Aspergillus. These data can be interpreted in terms
of two gene duplication events that produced a minimum of three catalase
gene family members that subsequently evolved in response to environmental
demands. Horizontal gene transfer may have been responsible for the group
II mixture of bacterial and fungal large-subunit catalases.
相似文献
84.
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86.
Giada Sebastiani Rasha Alshaalan Philip Wong Maria Rubino Ayat Salman Peter Metrakos Marc Deschenes Peter Ghali 《PloS one》2015,10(6)
Background & Aims
Non-invasive diagnostic methods for liver fibrosis predict clinical outcomes in viral hepatitis and nonalcoholic fatty liver disease (NAFLD). We specifically evaluated prognostic value of non-invasive fibrosis methods in nonalcoholic steatohepatitis (NASH) against hepatic venous pressure gradient (HVPG) and liver histology.Methods
This was a retrospective cohort study of 148 consecutive patients who met the following criteria: transjugular liver biopsy with HVPG measurement; biopsy-proven NASH; absence of decompensation; AST-to-Platelets Ratio Index (APRI), fibrosis-4 (FIB-4), NAFLD fibrosis score, ultrasound, hepatic steatosis index and Xenon-133 scan available within 6 months from biopsy; a minimum follow-up of 1 year. Outcomes were defined by death, liver transplantation, cirrhosis complications. Kaplan–Meier and Cox regression analyses were employed to estimate incidence and predictors of outcomes, respectively. Prognostic value was expressed as area under the curve (AUC).Results
During a median follow-up of 5 years (interquartile range 3-8), 16.2% developed outcomes, including 7.4% who died or underwent liver transplantation. After adjustment for age, sex, diabetes, the following fibrosis tools predicted outcomes: HVPG >10mmHg (HR=9.60; 95% confidence interval [CI] 3.07-30.12), histologic fibrosis F3-F4 (HR=3.14; 1.41-6.95), APRI >1.5 (HR=5.02; 1.6-15.7), FIB-4 >3.25 (HR=6.33; 1.98-20.2), NAFLD fibrosis score >0.676 (HR=11.9; 3.79-37.4). Prognostic value was as follows: histologic fibrosis stage, AUC=0.85 (95% CI 0.76-0.93); HVPG, AUC=0.81 (0.70-0.91); APRI, AUC=0.89 (0.82-0.96); FIB-4, AUC=0.89 (0.83-0.95); NAFLD fibrosis score, AUC=0.79 (0.69-0.91). Neither histologic steatosis nor non-invasive steatosis methods predicted outcomes (AUC<0.50).Conclusions
Non-invasive methods for liver fibrosis predict outcomes of patients with NASH. They could be used for serial monitoring, risk stratification and targeted interventions. 相似文献87.
Erf2, a Novel Gene Product That Affects the Localization and Palmitoylation of Ras2 in Saccharomyces cerevisiae 总被引:3,自引:0,他引:3
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Doug J. Bartels David A. Mitchell Xiangwen Dong Robert J. Deschenes 《Molecular and cellular biology》1999,19(10):6775-6787
Plasma membrane localization of Ras requires posttranslational addition of farnesyl and palmitoyl lipid moieties to a C-terminal CaaX motif (C is cysteine, a is any aliphatic residue, X is the carboxy terminal residue). To better understand the relationship between posttranslational processing and the subcellular localization of Ras, a yeast genetic screen was undertaken based on the loss of function of a palmitoylation-dependent RAS2 allele. Mutations were identified in an uncharacterized open reading frame (YLR246w) that we have designated ERF2 and a previously described suppressor of hyperactive Ras, SHR5. ERF2 encodes a 41-kDa protein with four predicted transmembrane (TM) segments and a motif consisting of the amino acids Asp-His-His-Cys (DHHC) within a cysteine-rich domain (CRD), called DHHC-CRD. Mutations within the DHHC-CRD abolish Erf2 function. Subcellular fractionation and immunolocalization experiments reveal that Erf2 tagged with a triply iterated hemagglutinin epitope is an integral membrane protein that colocalizes with the yeast endoplasmic reticulum marker Kar2. Strains lacking ERF2 are viable, but they have a synthetic growth defect in the absence of RAS2 and partially suppress the heat shock sensitivity resulting from expression of the hyperactive RAS2(V19) allele. Ras2 proteins expressed in an erf2Delta strain have a reduced level of palmitoylation and are partially mislocalized to the vacuole. Based on these observations, we propose that Erf2 is a component of a previously uncharacterized Ras subcellular localization pathway. Putative members of an Erf2 family of proteins have been uncovered in yeast, plant, worm, insect, and mammalian genome databases, suggesting that Erf2 plays a role in Ras localization in all eucaryotes. 相似文献
88.
Mice of the TO Swiss strain received diets containing different amounts of saturated or unsaturated fat throughout life. These diets produced characteristic changes in cardiac phospholipid fatty acid composition, but produced no significant differences in fatty acid composition of phospholipids from a crude membrane fraction of brain. When littermates of these animals were exposed to ethanol vapour in an inhalation chamber it was observed that mice which had received a diet high in saturated fat lost the righting reflex at an estimated concentration of ethanol in blood higher than that required for mice receiving a control diet, or a diet rich in polyunsaturated fat. Analysis of the brain membrane fraction from those animals which had received ethanol revealed that mice receiving the highly saturated fat diet now had a significantly greater proportion of saturated fatty acids in brain membrane phospholipids. These results are discussed in relation to the hypothesis that brain membrane lipid composition may influence the behavioural response to ethanol. 相似文献
89.
The two-step collagenase perfusion method originally developed for the high yield isolation of parenchymal cells from adult rat livers has been adapted to rats of 1 day, 1 week, and 2 weeks of age. The use of this method to isolate hepatocytes from five or six rats of the respective ages demonstrated its reliability in terms of cell yield, percentage of single cells, and cell viability. In all cases, hepatocytes attach with high efficiency to fibronectin precoated dishes using serum-free culture medium. The dynamics of spreading is faster for newborn hepatocytes than adult ones. The functional integrity of these parenchymal liver cells was assessed by their capacity to secrete albumin and alpha-fetoprotein in serum-free medium and to express lactate dehydrogenase activity over a 24-hr period in primary culture. 相似文献
90.
Acylation and prenylation of proteins 总被引:5,自引:0,他引:5