Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.

Insulin-like growth factor-I-stimulated glucose transport in myotubes derived from chicken muscle satellite cells

Abstract: The effects of insulin and insulin-like growth factor-I (IGF-I) on glucose transport were compared in myotubes derived from chicken breast muscle satellite cells in vitro. Myotubes were incubated (for 0.5 or 4 h) with or without glucose in the presence or absence of insulin or IGF-I. Glucose uptake was subsequently measured by the incorporation of 2-[1,2-3H(N)] deoxy-D-glucose ([3H]2DG) in glucose-free medium (10 min at 20 degrees C). Glucose uptake was almost completely abolished by the addition of cytochalasin B or phloretin. It was increased by a decrease in glucose concentration in the incubation medium. Insulin (5 mg/l) stimulated [3H]2DG uptake to a maximum of 43 +/- 10% above basal after 30-min incubation and 101 +/- 15% after 4-h incubation. IGF-I and insulin at equimolar concentrations (25 micrograms/l and 20 micrograms/l respectively) were almost equipotent after 0.5 h but after 4-h incubation IGF-I was 17-fold more potent, suggesting that this 'late' effect was mediated through the IGF-I receptor. Incubation with cycloheximide suggested that the effect of IGF-I involved increased protein synthesis. The results suggest that chicken myotubes express a glucose transporter which is regulated by IGF-I and glucose concentration. However, they do not appear to express a typical insulin-responsive transport system.

Effect of incubation conditions on the enrichment of pyrene-degrading bacteria identified by stable-isotope probing in an aged, PAH-contaminated soil.

Abstract: To determine whether the diversity of pyrene-degrading bacteria in an aged polycyclic aromatic hydrocarbon-contaminated soil is affected by the addition of inorganic nutrients or by slurrying the soil, various incubation conditions (all including phosphate buffer) were examined by mineralization studies and stable-isotope probing (SIP). The addition of nitrogen to either continuously mixed slurry or static field-wet soil incubations increased the rate and extent of mineralization of [14C]pyrene, with the most rapid mineralization observed in slurried, nitrogen-amended soil. Microcosms of slurry and static field-wet soil amended with nitrogen were also examined by SIP with [U-13C]pyrene. Recovered 13C-enriched deoxyribonucleic acid (DNA) was analyzed by denaturing-gradient gel electrophoresis (DGGE) and 16S ribosomal ribonucleic acid (rRNA) gene clone libraries. DGGE profiles of 13C-enriched DNA fractions from both incubation conditions were similar, suggesting that pyrene-degrading bacterial community diversity may be independent of treatment method. The vast majority (67 of 71) of the partial sequences recovered from clone libraries were greater than or equal to 97% similar to one another, 98% similar to sequences of pyrene-degrading bacteria previously detected by SIP with pyrene in different soil, and only 89% similar to the closest cultivated genus. All of the sequences recovered from the field-wet incubation and most of the sequences recovered from the slurry incubation were in this clade. Of the four sequences from slurry incubations not within this clade, three possessed greater than 99% similarity to the 16S rRNA gene sequences of phylogenetically dissimilar Caulobacter spp.

Incubation and Nest-Building Behaviour of Black-Headed Gulls

Abstract: (1) Parental behaviour, and its development from incubation behaviour during the reproductive season, is described. (2) Day to day observations of the natural situation showed that elements of the incubation pattern persist throughout the post-hatching period but progressively decline in quantity, duration and completeness. (3) Substitution of eggs for chicks also showed that the readiness to show incubation responses in a standard incubation situation declines progressively during the post-hatching period. (4) A certain amount of experience with hatched chicks renders Black-headed Gulls incapable of immediately returning to sustained incubation behaviour if the conditions of the incubation period are restored. (5) Failure of the eggs to hatch results in extension of the incubation behaviour period beyond the normal time. (6) Premature introduction of hatched chicks in the nests of incubating gulls can cause the gulls to switch to parental behaviour and so end the incubation behaviour period before the normal time. (7) The timing of the change from incubation to parental behaviour is thus mainly a matter of external control. (8) Certain of the relationships found to hold between responses having an incubation function and responses having a nest-building function in the earlier phases also hold in the post-hatching period.