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1.
Stanislav Lhota Veronika Roubov Vendula Gregorov Martina Kone
n 《American journal of primatology》2019,81(9)
Grooming in primates is often considered a “currency” that can be exchanged for other “services” or “commodities” such as reciprocal grooming, coalitionary support, infant handling, tolerance around food sources, active food sharing, or mating opportunities. Previous studies on primate grooming‐for‐sex exchange viewed the males as the demanding class, with the females as suppliers of mating opportunities. In this study, we examine the broader context of grooming‐for‐mating exchange in Barbary macaques in Gibraltar. Our data show that Barbary macaque males groom females with whom they are mating more frequently and for longer periods than other females, and the relationship between grooming and mating remains significant in both sexual and nonsexual contexts. In addition, females groomed males with whom they were mating more frequently and for longer periods than other males. In both sexes, grooming was observed to be far more frequent and to occur for longer durations in sexual compared to nonsexual contexts. We did not find any difference in grooming behavior between presexual and postsexual contexts. Our data suggest that there is no simple model to describe Barbary macaque grooming patterns in sexual contexts. Although our results are partly consistent with male use of grooming as payment for mating, broadly assessed grooming‐mating patterns cannot be solely explained by a male‐driven grooming‐for‐mating exchange. 相似文献
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This is the first report on using green fluorescent protein (GFP) as a pH reporter in plants. Proton fluxes and pH regulation play important roles in plant cellular activity and therefore, it would be extremely helpful to have a plant gene reporter system for rapid, non‐invasive visualization of intracellular pH changes. In order to develop such a system, we constructed three vectors for transient and stable transformation of plant cells with a pH‐sensitive derivative of green fluorescent protein. Using these vectors, transgenic Arabidopsis thaliana and tobacco plants were produced. Here the application of pH‐sensitive GFP technology in plants is described and, for the first time, the visualization of pH gradients between different developmental compartments in intact whole‐root tissues of A. thaliana is reported. The utility of pH‐sensitive GFP in revealing rapid, environmentally induced changes in cytoplasmic pH in roots is also demonstrated. 相似文献
4.
Xiuyun Ye Shigeru Yoshida T. B. Ng 《The international journal of biochemistry & cell biology》2000,32(11-12)
A mild and rapid method is described for isolating various milk proteins from bovine rennet whey. β-Lactoglobulin from bovine rennet whey was easily adsorbed on and desorbed from a weak anion exchanger, diethylaminoethyl-Toyopearl. However, α-lactalbumin could not be adsorbed onto the resin. α-Lactalbumin and β-lactoglobulin from rennet whey could also be adsorbed and separated using a strong anion exchanger, quaternary aminoethyl-Toyopearl. The rennet whey was passed through a strong cation exchanger, sulphopropyl-Toyopearl, to separate lactoperoxidase and lactoferrin. α-Lactalbumin and β-lactoglobulin were adsorbed onto quaternary aminoethyl-Toyopearl. α-Lactalbumin was eluted using a linear (0–0.15 M) concentration gradient of NaCl in 0.05 M Tris–HCl buffer (pH 8.5). Subsequently, β-lactoglobulin B and β-lactoglobulin A were eluted from the column with 0.05 M Tris–HCl (pH 6.8), using a linear (0.1–0.25 M) concentration gradient of NaCl. The yields were 1260 mg α-lactalbumin, 1290 mg β-lactoglobulin B and 2280 mg β-lactoglobulin A from 1 l rennet whey. 相似文献
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Summary Equivalent-circuit impedance analysis experiments were performed on the urinary bladders of freshwater turtles in order to quantify membrane ionic conductances and areas, and to investigate how changes in these parameters are associated with changes in the rate of proton secretion in this tissue. In all experiments, sodium reabsorption was inhibited thereby unmasking the electrogenic proton secretion process. We report the following: (1) transepithelial impedance is represented exceptionally well by a simple equivalent-circuit model, which results in estimates of the apical and basolateral membrane ionic conductances and capacitances; (2) when sodium transport is inhibited with mucosal amiloride and serosal ouabain, the apical and basolateral membrane conductances and capacitances exhibit a continual decline with time; (3) this decline in the membrane parameters is most likely caused by subtle time-dependent changes in cell volume, resulting in changes in the areas of the apical and basolateral membranes; (4) stable membrane parameters are obtained if the tissue is not treated with ouabain, and if the oncotic pressure of the serosal solution is increased by the addition of 2% albumin; (5) inhibition of proton secretion using acetazolamide in CO2 and HCO
3
–
-free bathing solutions results in a decrease in the area of the apical membrane, with no significant change in its specific conductance; (6) stimulation of proton transport with CO2 and HCO
3
–
-containing serosal solution results in an increase in the apical membrane area and specific conductance. These results show that our methods can be used to measure changes in the membrane electrophysiological parameters that are related to changes in the rate of proton transport. Notably, they can be used to quantify in the live tissue, changes in membrane area resulting from changes in the net rates of endocytosis and exocytosis which are postulated to be intimately involved in the regulation of proton transport. 相似文献
8.
Ataxia telangiectasia: the effects of chemical mutagens and x-rays on sister chromatid exchanges in blood lymphocytes 总被引:4,自引:0,他引:4
S M Galloway 《Mutation research》1977,45(3):343-349
It is now possible to examine in detail exchanges between sister chromatids (SCEs) and to attempt to investigate the relationships of such exchanges to aberration formation and DNA-repair mechanisms. The frequency of SCEs is dramatically increased by chemical mutagens and may reflect the level of DNA damage. Lymphocytes from patients with ataxia telangiectasis (AT) show high levels of spontaneous chromosome damage and are hypersentive to ionising radiations and it was of interest to examine the levels of SCE induced in these cells by various mutagens. The frequencies of SCE after treatment with X=rays or three chemical mutagens were equivalent to those in normal cells. The effects of fluorodeoxyuridine and deoxycytidine on SCE frequencies were also tested. 相似文献
9.
《Plant Ecology & Diversity》2013,6(2-3):227-241
Background: Although forest floor forms a large biomass pool in forested peatlands, little is known about its role in ecosystem carbon (C) dynamics. Aim: We aimed to quantify forest floor photosynthesis (P FF) and respiration (R FF) as a part of overall C dynamics in a drained peatland forest in southern Finland. Methods: We measured net forest floor CO2 exchange with closed chambers and reconstructed seasonal CO2 exchange in the prevailing plant communities. Results: The vegetation was a mosaic of plant communities that differed in CO2 exchange dynamics. The reconstructed growing season P FF was highest in the Sphagnum community and lowest in the feather moss communities. On the contrary, R FF was highest in the feather moss communities and lowest in the Sphagnum community. CO2 assimilated by the forest floor was 20–30% of the total CO2 assimilated by the forest. The forest floor was a net CO2 source to the atmosphere, because respiration from ground vegetation, tree roots and decomposition of soil organic matter exceeded the photosynthesis of ground vegetation. Conclusions: Tree stand dominates C fluxes in drained peatland forests. However, forest floor vegetation can have a noticeable role in the C cycle of peatlands drained for forestry. Similarly to natural mires, Sphagnum moss-dominated communities were the most efficient assimilators of C. 相似文献
10.
Harish Kumar Jayant B. Udgaonkar 《Protein science : a publication of the Protein Society》2021,30(4):785
Amyloid fibrillar aggregates isolated from the brains of patients with neurodegenerative diseases invariably have post‐translational modifications (PTMs). The roles that PTMs play in modulating the structures and polymorphism of amyloid aggregates, and hence their ability to catalyze the conversion of monomeric protein to their fibrillar structure is, however, poorly understood. This is particularly true in the case of tau aggregates, where specific folds of fibrillar tau have been implicated in specific tauopathies. Several PTMs, including acetylation at Lys 280, increase aggregation of tau in the brain, and increase neurodegeneration. In this study, tau‐K18 K280Q, in which the Lys 280 → Gln mutation is used to mimic acetylation at Lys 280, is shown, using HX‐MS measurements, to form fibrils with a structural core that is longer than that of tau‐K18 fibrils. Measurements of critical concentrations show that the binding affinity of monomeric tau‐K18 for its fibrillar counterpart is only marginally more than that of monomeric tau‐K18 K280Q for its fibrillar counterpart. Quantitative analysis of the kinetics of seeded aggregation, using a simple Michaelis–Menten‐like model, in which the monomer first binds and then undergoes conformational conversion to β‐strand, shows that the fibrils of tau‐K18 K280Q convert monomeric protein more slowly than do fibrils of tau‐K18. In contrast, monomeric tau‐K18 K280Q is converted faster to fibrils than is monomeric tau‐K18. Thus, the effect of Lys 280 acetylation on tau aggregate propagation in brain cells is expected to depend on the amount of acetylated tau present, and on whether the propagating seed is acetylated at Lys 280 or not. 相似文献