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81.
Patrick Martin Benjamin AS Van Mooy Abigail Heithoff Sonya T Dyhrman 《The ISME journal》2011,5(6):1057-1060
In low-phosphorus (P) marine systems, phytoplankton replace membrane phospholipids with non-phosphorus lipids, but it is not known how rapidly this substitution occurs. Here, when cells of the model diatom Thalassiosira pseudonana were transferred from P-replete medium to P-free medium, the phospholipid content of the cells rapidly declined within 48 h from 45±0.9 to 21±4.5% of the total membrane lipids; the difference was made up by non-phosphorus lipids. Conversely, when P-limited T. pseudonana were resupplied with P, cells reduced the percentage of their total membrane lipids contributed by a non-phosphorus lipid from 43±1.5 to 7.3±0.9% within 24 h, whereas the contribution by phospholipids rose from 2.2±0.1 to 44±3%. This dynamic phospholipid reservoir contained sufficient P to synthesize multiple haploid genomes, suggesting that phospholipid turnover could be an important P source for cells. Field observations of phytoplankton lipid content may thus reflect short-term changes in P supply and cellular physiology, rather than simply long-term adjustment to the environment. 相似文献
82.
HUGO M. RAMÍREZ‐TOBÍAS CECILIA B. PEÑA‐VALDIVIA J. ROGELIO AGUIRRE R. J. ANTONIO REYES‐AGÜERO ADRIANA B. SÁNCHEZ‐URDANETA SALVADOR VALLE G. 《Plant Species Biology》2012,27(2):124-137
The genetic diversity of Agave plants is threatened by clonal commercial reproduction and climatic change. Sexual reproduction is uncommon and research on seed germination is scarce. The present study evaluated the seed germination of Agave lechuguilla, Agave striata, Agave americana var. marginata, Agave asperrima, Agave cupreata, Agave duranguesis, Agave angustifolia ssp. tequilana and Agave salmiana at constant temperatures (10, 15, 20, 25, 30, 35 and 40°C). Initial imbibition (after the first 12 h) was significantly variable among species, positively correlated with seed weight (r = 0.6560, P < 0.001) and increased with temperature (from 35% at 10°C to 66% at 40°C). Temperature affected maximum imbibition (83–150%) for A. asperrima, A. lechuguilla, A. salmiana and A. striata; other species averaged 110%. Most germination kinetics best fitted a logistic model, whereas only a few treatments fit a Weibull model. The time to germination onset diminished (P < 0.05) from 125–173 h at 15°C to 68–84 h at 25°C, and then ascended to 84–196 h at 35°C. The mean germination rate and seed germination percentage after 312 h peaked at 25°C (0.50–0.95% seeds/h and 85–99%, respectively) and fell (P < 0.05) to near zero at 10 and 40°C. Temperatures of 10, 35 and 40°C were partially lethal to A. asperrima, A. duranguensis and A. salmiana seeds. The time to germination onset, seed germination percentage after 312 h and mean germination rate are best described by a Gaussian distribution, with its optimum at approximately 25°C. Thus, optimum temperatures are related to the ecological characteristics of each species area. 相似文献
83.
The authors studied and provided treatment to patients with the complaint of gummy smile. Between October of 2009 and January of 2011, 52 unaesthetic smiles were evaluated and treated with onabotulinum toxin A. Botulinum toxin injection was an effective treatment, with an average satisfaction level of 9.75 on a 10-point scale. The levator labii superioris alaeque nasi is the ideal muscle for injection, and lopsided smiles could be resolved also with onabotulinum toxin A asymmetric injection. Gummy smile treatment with onabotulinum toxin A into the levator labii superioris alaeque nasi muscle is an effective method, with minimum risk of complications and very high patient satisfaction. 相似文献
84.
Thyroid hormone binding proteins of rat liver cytosol were characterized. Glutathione-S-transferases were identified among major cytosolic proteins adsorbed by thyroxine affinity matrices. The Ya and Yb subunits of the glutathione-S-transferases were also principal proteins of cytosol covalently labeled with 3,3',5-triiodo-L-thyronine (T3) or 3,3',5,5'-tetraiodo-L-thyronine (T4) by photoaffinity methods. T3 and T4, but not L-thyronine or iodinated tyrosines, were bound with high affinity to purified glutathione-S-transferases and were potent inhibitors of their enzymatic activities. These results suggest that glutathione-S-transferases have the potential to function in the intracellular binding and transport of thyroid hormones. The proteins provide a means for regulating the action and metabolism of thyroid hormones by acting as high capacity binding components. 相似文献
85.
Genetic variability in the complete mitochondrial control region of the Eurasian otter (Lutra lutra) in the Iberian Peninsula 总被引:1,自引:0,他引:1
M. PÉREZ-HARO J. VIÑAS F. MAÑAS A. BATET J. RUIZ-OLMO C. PLA 《Biological journal of the Linnean Society. Linnean Society of London》2005,86(4):397-403
Sequencing of the complete mitochondrial DNA control region from 31 samples of the Eurasian otter, Lutra lutra , enabled us to establish the length and structure of this fragment, as well as to describe, for the first time, the RS3 repetitive region located at the 3' end. In addition, genetic variability of the 5' end was examined in 63 individuals, 57 of which were wild otters from the Iberian Peninsula and six captive reared otters. This analysis resulted in extremely low variability. All the samples from the Iberian Peninsula share a single haplotype, Lut 1, the most common haplotype in Europe. Captive otters showed two haplotypes: Lut 3, which has been described in wild otters from eastern Germany, and Lut 6, an haplotype not described to date. Higher variability was observed in the repetitive RS3 region. The tandem repeat was composed of an array of ten repeat units of 22 bp with differences in the repetitive motifs that differed in the arrays of different specimens. In total, 20 different haplotypes from 31 individuals were found. However, the geographical distribution of these haplotypes did not generate a phylogeographical signal. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 397–403. 相似文献
86.
87.
FREE CHOICE PROFILING OF CHILEAN GOAT CHEESE 总被引:1,自引:0,他引:1
Different goat cheeses from Chile were studied by Free-Choice Profile (FCP) analysis. Generalized Procrustes Analysis (GPA) applied to FCP data permitted differentiation between samples and informed on the attributes responsible for the observed differences. Appearance was a dominant factor in discriminating samples and to a lesser degree textural variables were also correlated with GPA dimensions. In acceptability the fresh cheeses were significantly preferred over the ripened ones. 相似文献
88.
Plasminogen activator inhibitor-2 (PAI-2) specifically inhibits plasminogen activators, extracellular fibrinolytic serine proteases that are also implicated in brain plasticity and toxicity. Primarily localized intracellularly, PAI-2 is thought to also counteract apoptosis mediated by a currently undefined intracellular protease. Here we localized PAI-2 mRNA through in situ hybridization in brain cryosections derived from normal adult mice or after kainate excitation. We found that in the normal brain PAI-2 mRNA was confined to an area within the accumbens nucleus shell. After kainate was injected (i.p.), PAI-2 mRNA was substantially and rapidly (within 2 h) induced in neuron-like cells primarily in layers II–III of the neocortex; the cingulate, piriform, entorhinal and perirhinal cortices; the olfactory bulb, nucleus and tubercle; in the accumbens nucleus, shell and core; throughout the caudate putamen and the amygdaloid complex; in the CA1 and CA3 areas of the hippocampus, and in the parasubiculum. These findings suggest that PAI-2 could play a role in the accumbens nucleus as well as in activity-related events associated with olfactory, striatal, and limbic structures. 相似文献
89.
Background
There are four widely used experimental strains of N. gonorrhoeae, one of which has been sequenced and used as the basis for the construction of a multi-strain, mutli-species pan-neisserial microarray. Although the N. gonorrhoeae population structure is thought to be less diverse than N. meningitidis, there are some recognized gene-complement differences between strains, including the 59 genes of the Gonococcal Genetic Island. In this study we have investigated the three experimental strains that have not been sequenced to determine the extent and nature of their similarities and differences. 相似文献90.