Incubation

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

Release of neurophypophysial hormones in vitro

Abstract: 1. The rate of release of neurohypophysial hormones in vitro, using isolated, halved neural lobes of the rat in an incubation medium containing excess K+ and Ca2+, was measured. The highest average rate of release was observed between 10 and 20 min after commencement of incubation. 2. Incubation of isolated, halved rat neural lobes in the presence of acetylcholine, with or without eserine, did not stimulate hormone release. When complete isolated hypothalamo-neurohypophysial systems were incubated in a suspension medium containing 10−7 mg/ml. acetylcholine a significant increase in the release of oxytocin occurred (P < 0·01); the increase in vasopressin release was less pronounced (P < 0·05). 3. Uptake of O2 by the isolated, halved neural lobes and the hypothalamo-neurohypophysial systems continued for 2-3 hr, i.e. in excess of the experimental incubation time. 4. During the first 40 min of incubation the control halved neural lobes increased in weight; the neural lobes incubated in buffer containing high potassium and calcium showed no increase in weight. 5. Neural lobes incubated in buffer containing excess K+ and Ca2+ contained about 3 times as much potassium as controls. The sodium content was not affected significantly. 6. Factors involved in the process of neurohypophysial hormone release are discussed.

Effect of short periods of high incubation temperature on hatchability and incidence of embryo pathology of turkey eggs.

Abstract: 1. Turkey eggs were incubated at 38.0 degrees and 38.5 degrees C at different stages of embryo development and for periods of 3 to 25 d. Results were compared with control eggs incubated at 37.5 degrees C. The age of mortality, the incidence of malpositions and the incidence of morphological abnormalities were recorded from all unhatched eggs. 2. Eggs incubated at 38.5 degrees C for 5 or more days hatched significantly less well than eggs incubated at 37.5 degrees C. Eggs incubated at 38.5 degrees C for 3 d hatched worse than controls but not significantly so. Eggs incubated between 0 and 25 d and 7 and 12 d but not between 0 and 6, 13 and 18 and 19 and 25 d, at 38.0 degrees C had significantly lower hatchabilities than eggs incubated at 37.5 degrees C. 3. Lowest hatchabilities were obtained when the eggs were incubated at high temperatures between 7 to 12 d and 6 to 10 d, indicating that embryos at this stage of development are more likely to succumb to high temperature than at other ages. 4. Increases in embryo mortality due to overheating were seen in weeks 3 and 4 of incubation and at the pipping stage. This was observed even when the period of overheating occurred in weeks 1 and 2 of incubation. 5. Embryos malpositioned with their head in the small end of the egg were seen at a higher incidence when overheating in the 2nd or 3rd quarter of the incubation period.

Do energetic demands constrain incubation scheduling in a biparental species

Abstract: The high energetic demands of incubation in birds may be an important ecological factor limiting the evolution of life-history traits, such as clutch size. In biparental species, however, the demands of incubation may not be a major constraint because there may always be sufficient feeding time available for the off-duty bird to regain energy used during an incubation bout. We investigated whether the energetic demands of incubation constrain optimum incubation bout length in a biparental incubator by decreasing the energetic demands of incubation. We put an insulated cup around the lining of semipalmated sandpiper nests so that the rate of cooling of eggs was reduced by 21%. Semipalmated sandpipers responded by increasing their mean incubation bout length of around 11.1 h by about 10%. Bout lengths in unmanipulated natural nests became longer as hatch approached (incubation stage), and this was independent of weather. Bout lengths may have decreased with increasing rainfall and were independent of time of day. The results suggest that bout length in semipalmated sandpipers is constrained by their cumulative energetic expenditure during an incubation bout, and this is determined partly by the high costs of steady-state incubation. The results also suggest that the incubating bird determines the bout length rather than the returning bird. Semipalmated sandpipersmay have maximized incubation bout length to minimize changeovers during incubation because these probably increasepredation risk. Selection to minimize the frequency of changeover may then be a factor contributing to the evolution ofbiparental care and life-history traits in semipalmated sandpipers. Copyright 2003.

Phosphatase activity of soils as influenced by lime and other treatments

Abstract: In laboratory incubation experiments liming with Ca(OH)2, CaCO3, or MgCO3 inhibited the phosphatase enzyme activity as measured by determination of phenol or phosphorus released from disodium phenyl phosphate. Chloride and sulphate salts of calcium and magnesium had no appreciable effect on the measured activity. Incubation for 9 months reduced the activity in a group of acid soils but not in a group of nearly neutral soils. Addition of phosphate prior to incubation had no effect on activity in either group.In buffer systems with the pH controlled over the range pH 2.0 to 11.0, activity in samples of an acid mineral soil increased gradually from pH 2.0 to a maximum at about pH 7.0, and then declined rapidly. The occurrence of peaks of optimum activity at pH 5.0 and 9.5 indicated the presence of both acid and alkaline phosphatases in an organic soil.Although there was no significant relationship between phosphatase activity and pH, clay content, nitrogen, and total carbon content of 10 mineral soils, there...