Incubation

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

Some Factors Influencing Respiration and Glycolysis in Ehrlich Ascites Tumor Cells

Abstract: Summary The paper presents a study of various environmental factors which influence respiration, glycolysis, and the Crabtree Effect in the Ehrlich ascites carcinoma cells. The factors examined for influence on respiration include: (1) pH in the presence and absence of glucose and (2) varying concentrations of inorganic phosphate in: ( a ) media used to wash the cells, ( b ) incubation media, with no supplementary substrate, with and without Tris buffer, ( c ) incubation medium containing 200 mg. per cent of dl-lactate, ( d ) incubation media containing 55 mg. per cent of glucose and 37 mm Tris, ( e ) incubation medium containing only 0.5 mg. per cent glucose, ( f ) incubation medium containing 110 mg. per cent of 2-deoxyglucose, and ( g ) incubation media containing 110 mg. per cent of glucose, 37 mm Tris and 7 × 10 -5 m 2,4-dinitrophenol. The most significant observations concern the changes in glycolysis, respiration, and the Crabtree Effect when inorganic phosphate concentration was lowered from 15 to 5 mm. Above 15 mm all were independent of phosphate, and below 5 mm all were dependent on phosphate concentration.

Variation in the characteristics of 10 mouse-passaged scrapie lines derived from five scrapie-positive sheep.

Abstract: Ten mouse-passaged scrapie lines were initiated from five sheep with clinical scrapie. Of the lines, five were initiated and passaged exclusively in mice with the s7s7 genotype and the remaining five lines were initiated in mice with the p7p7 genotype, with two of these lines subsequently being passaged exclusively in p7p7 mice and two being passaged mainly in p7p7 mice. Lines were passaged three or four times and two parameters were compared: incubation period and the induction of a weight increase during the preclinical period. Considerable variation in the incubation periods was found between the different passage lines at similar passage levels, with a range in s7s7 mice of 113 days to greater than 450 days and a range in p7p7 mice of 219 days to greater than 500 days. All of the lines passaged exclusively in s7s7 mice had shorter incubation periods in this mouse genotype than in p7p7 mice, whereas of the five lines initiated in p7p7 mice, two had shorter incubation periods in p7p7 mouse strains. C57BL mice were used as the indicator strain and most of the lines caused an increase in weight during the preclinical phase of disease compared to control mice injected with normal brain homogenates. For both parameters, incubation period and preclinical weight increase, differences were seen in lines that had identical passage histories, suggesting that an informational molecule separate from host genomic material must specify scrapie strain differences.

Biparental incubation patterns in a high-Arctic breeding shorebird: how do pairs divide their duties?

Abstract: In biparental species, parents may be in conflict over how much they invest into their offspring. To understand this conflict, parental care needs to be accurately measured, something rarely done. Here, we quantitatively describe the outcome of parental conflict in terms of quality, amount, and timing of incubation throughout the 21-day incubation period in a population of semipalmated sandpipers (Calidris pusilla) breeding under continuous daylight in the high Arctic. Incubation quality, measured by egg temperature and incubation constancy, showed no marked difference between the sexes. The amount of incubation, measured as length of incubation bouts, was on average 51min longer per bout for females (11.5h) than for males (10.7h), at first glance suggesting that females invested more than males. However, this difference may have been offset by sex differences in the timing of incubation; females were more often off nest during the warmer period of the day, when foraging conditions were presumably better. Overall, the daily timing of incubation shifted over the incubation period (e.g., for female incubation from evening-night to night-morning) and over the season, but varied considerably among pairs. At one extreme, pairs shared the amount of incubation equally, but one parent always incubated during the colder part of the day; at the other extreme, pairs shifted the start of incubation bouts between days so that each parent experienced similar conditions across the incubation period. Our results highlight how the simultaneous consideration of different aspects of care across time allows sex-specific investment to be more accurately quantified.

In vitro studies on glycerol transformation by rumen microorganisms

Abstract: Rumen fluid from sheep (non adapted to glycerol) was incubated up to six hours under anaerobic conditions with buffer and mineral solution. Wheat starch was added as substrate in an amount of 1g DM per vessel. Glycerol was additionally admitted to rumen fluid in amounts of 5 to 50% of starch. Carrier-free 14C-glycerol (1.3-labelled) or 15N-labelled NH4Cl were added to different incubation vessels. The disappearance rate of glycerol depended from the amount of added glycerol and incubation time. More than 90% of glycerol disappeared in 2 hours (5% addition), 4 hours (10% addition) and 6 hours (15 to 25% addition) respectively. The sum of volatile fatty acids elevated significant with a higher glycerol addition and 6 hours incubation time. The concentration of propionic acid increased also in dependence of the added glycerol amount and the longer incubation time. The proportion of acetic acid to propionic acid changed from high values (3.5 to 4.0, without glycerol) to the lowest value from 2.5 after 6 hours incubation time and 25% glycerol addition. The most radioactivity of added 14C-glycerol was found in propionic acid and only up to 11% in CO2. 14C-radioactivity was not detected in methane, lactic acid and acetic acid respectively. The 15N-labelling of TCA-precipitable N-fraction was not influenced by glycerol supplementation but the 15N-incorporation in the bacterial nitrogen fraction was lower in the vessels with glycerol.

Development of the chicken as a model for prenatal stress.

Abstract: Exposing a pregnant mammal to stressors causes behavioral and physiological alterations in her offspring ("prenatal stress"); however, elucidation of the underlying mechanism is hindered by an inability to control maternal compounds that may affect the fetus. We designed this experiment to determine if the autonomously developing chicken embryo could be developed as a model for prenatal stress. On d 16 of incubation, eggs were treated with: 1) 60 ng corticosterone (CORT), 2) elevated incubation temperature (40.6 degrees C) for 24 h (HEAT), or 3) no treatment (Control). Chicks from all three treatments hatched at similar weights; however, HEAT chicks weighed less by 100 d of age and remained lighter until the end of the study (P 0.20) among treatments, basal plasma corticosterone concentrations tended (P 0.20). At 11-wk, HEAT birds had heavier adrenal glands than did Control birds (P 0.10). Administration of corticosterone during incubation replicated some, but not all, of the effects seen in prenatal stress in mammals.