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PubMed2003

Interaction between maternal effects: onset of incubation and offspring sex in two populations of a passerine bird.

Maternal phenotype and maternal environment can profoundly affect the phenotype and fitness of offspring. Yet the causes of variation in such maternal effects are rarely known. Embryos in avian eggs cannot develop without being incubated and this creates an opportunity for maternal control of duration and onset of offspring development. However, females might adjust the start of incubation (e.g., coincident with the first egg or delayed until after egg-laying) in response to environmental conditions that they experience at the time of breeding. We studied two populations of the house finch ( Carpodacus mexicanus) that breed at the climatic extremes of the species' geographical range (Montana and Alabama) and found that in both populations, the timing of incubation onset was closely associated with the bias in the sequence in which male and female eggs were laid within a clutch. When females started incubation with the first egg, they produced sons and daughters in highly biased sequence, when females delayed the onset of incubation until after the egg-laying, the sequence of sons and daughters was not biased. Because in both populations, onset of incubation was associated with the ambient temperature, these results emphasize that maternal effects on offspring can be influenced by ecological conditions experienced by parental generation.

Animals↗

PubMed1990

Synergistic effects of lipid transfers and hepatic lipase in the formation of very small high-density lipoproteins during incubation of human plasma.

Studies have been performed to determine the involvement of very-low-density lipoproteins (VLDL), cholesteryl ester transfer protein (CETP) and hepatic lipase (HL) in the formation of very small HDL particles. Human whole plasma has been incubated for 6 h at 37 degrees C in the absence and in the presence of various additions. There was minimal formation of very small HDL in incubations of non-supplemented plasma or in plasma supplemented with either VLDL, CETP or HL alone; nor were small HDL prominent after incubating plasma supplemented with mixtures of VLDL plus CETP, VLDL plus HL or CETP plus HL. By contrast, when plasma was supplemented with a mixture containing all three of VLDL, CETP and HL, incubation resulted in an almost total conversion of the HDL fraction into very small particles of radius 3.7 nm. The appearance of these very small HDL was independent of activity of lecithin: cholesterol acyltransferase. It was, however, dependent on both duration of incubation and on the concentrations of the added VLDL, CETP and HL. The effects of these incubations was also assessed in terms of changes to the concentration and distribution of lipid constituents across the lipoprotein spectrum. It was found that not only did lipid transfers and HL exhibit a marked synergism in promoting a reduction in HDL particle size but also that HL, although deficient in intrinsic transfer activity, enhanced the CETP-mediated transfers of cholesteryl esters from HDL to other lipoprotein fractions.

Adult↗

PubMed1995

[14C]2-deoxyglucose uptake in the brain of the ring dove (Streptopelia risoria). II. Differential uptake at the onset of incubation.

Brain areas involved in the expression of incubation behaviour were identified in male ring dove at the onset of incubation using quantitative [14C]2-deoxyglucose (2DG) autoradiography. The uptake of 2DG in twenty-eight areas found in the hypothalamus and thalamus, and six areas in the forebrain were compared in control non-breeding and incubating birds. Although 2DG utilisation varied significantly between brain areas, significant differences between non-breeding males and incubating males were observed only in 4 of them. These were the nucleus tuberis, nucleus preopticus medialis, nucleus ovoidalis and paleostriatum primitivum. The uptake of 2DG was increased at the onset of incubation in the nucleus tuberis, nucleus preopticus medialis and nucleus ovoidalis and decrease in the paleostriatum primitivum. These findings are consistent with the hypothesis that these brain areas play a role in the initiation of incubation behaviour.

Analysis of Variance↗

PubMed1984

The effects of modifying incubation on prolactin secretion in free-living pied flycatchers.

Plasma prolactin concentrations in female pied flycatchers are high during incubation, but fall from 156 +/- 27 to 67 +/- 6 ng/ml (P less than 0.01) between 2 and 4 days after the young hatch. The timing of the fall in prolactin could be determined by factors associated with the hatching of the eggs and growth of the offspring; alternatively, prolactin may remain high for a fixed period (16 days) after the onset of incubation. To distinguish between these possibilities, eggs were exchanged between nest boxes to ensure incubation periods of either 10, 14, or 19 days by different females. The results showed that the period of high prolactin secretion was shortened by 2-4 days where the eggs hatched early, but, conversely, was not lengthened in those females with extended incubation periods, the levels actually falling in these birds before the eggs hatched. There was, however, a secondary rise in prolactin 3 days after hatching, when the level of 114 +/- 11 ng/ml 22 days after the onset of incubation was much higher than that (30 +/- 4 ng/ml) at a comparable stage in the control females. Thus, high prolactin secretion cannot be maintained for longer than 16-17 days in incubating birds, but newly hatched, naked young can stimulate prolactin release in female flycatchers over a flexible period.

Animals↗

PubMed1984

Increase of electrophoretic mobility and of content of soluble proteins of human plasma beta-lipoproteins by incubation of plasma in vitro.

Incubation of human plasma at 37 degrees C was shown to induce an increase in the electrophoretic mobility of beta-lipoproteins. beta-Lipoproteins were isolated by density gradient ultracentrifugation after such incubation and their composition was analysed. Incubation decreased the content of free cholesterol and increased that of soluble apolipoproteins. The soluble peptides appearing in LDL upon incubation showed 3 major and 2 minor bands upon polyacrylamide disc gel electrophoresis. Two of the major bands corresponded to apolipoprotein C-III-1 and C-III-2 and one of the minor to apolipoprotein C-II. The addition of an inhibitor to lecithin:cholesterol acyltransferase (LCAT) abolished the increase in electrophoretic mobility and to a large extent diminished the other reported effects of incubation. The hypothesis is put forward that during incubation of plasma at 37 degrees C the free cholesterol in the surface of LDL is removed through the action of LCAT, lipid transferases and exchange processes and is replaced in the surface shell by peptides which cause the change in electrophoretic mobility.

Apolipoprotein C-III↗

PubMed1988

The effect of sepsis in rats on skeletal muscle protein synthesis in vivo and in periphery and central core of incubated muscle preparations in vitro.

Recent studies demonstrated the development of a central, hypoxic core in incubated rat skeletal muscles. The influence of a central core on changes in protein synthesis rate, observed in incubated muscles from septic rats, is not known. In the present study, intact soleus muscles from 40 to 60-g sham-operated control rats and from septic rats (16 hours after cecal ligation and puncture) were incubated in vitro in a flaccid or stretched state. Protein synthesis rate was determined in whole muscle and in the central core and periphery of the muscle by measuring incorporation of 14C-phenylalanine into protein. Protein synthesis rate in vivo was measured with a flooding-dose technique using 3H-phenylalanine. The development of a central, hypoxic core in incubated muscles was assessed histochemically by staining the muscles for alpha-glucan phosphorylase activity. A central core with loss of alpha-glucan phosphorylase activity was noted after incubation for 30 minutes in both control and septic muscles. The protein synthesis rate was lower in the central core than in the periphery of incubated flaccid control muscles. In all other in vitro muscle preparations, however, there were no significant differences in protein synthesis rate among whole muscles, central core and periphery. Protein synthesis rate in septic muscles was reduced to a similar extent, approximately 20%, in vivo and in the different in vitro preparations, both when measured in whole muscle and in the central core or periphery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

Orienting and freezing responses in incubating ptarmigan hens.

Behavior studies and telemetric recordings of heart and respiration rates were performed on five wild and two captive, incubating, willow ptarmigan hens (Lagopus lagopus lagopus) and on four wild, incubating, Svalbard ptarmigan hens (Lagopus mutus hyperboreus). Sounds and sight of approaching humans, egg predators, or dogs near the nests elicited behavior in the hens which we have interpreted as an orienting response (OR) followed by freezing behavior. During both types of behavioral responses, heart rate was reduced from 204 +/- 39 (mean +/- SE) to 119 +/- 26 beats per minute and respiration from 25 +/- 2 to 12 +/- 3 breaths per minute. In wild incubating willow ptarmigan, further approach led to tachycardia and increased respiration. Some birds maintained freezing behavior, while others became restless before flying off. Two of the four incubating Svalbard ptarmigan hens showed the OR followed by freezing behavior accompanied by decreased heart and respiration rates. The other two birds showed flight response, restless behavior accompanied by increased heart and respiration rates. Flight behavior was also typical for willow ptarmigan incubating in captivity. Repeated auditory provocation of incubating hens caused progressive decrement in behavioral and cardiac responses that is interpreted as habituation of the OR.

Animals↗

PubMed1983

Organ growth in chick embryos incubated in 40% or 70% oxygen.

Incubation of eggs in 60% oxygen has been shown to enhance growth of the chick embryo. To determine whether oxygen accelerates growth over a range of concentrations, eggs were incubated in 40% or 70% O2. Control eggs, pair-matched by initial weight, were simultaneously incubated in room air (21% O2). Embryo and organ weights from matched pairs of eggs were compared on incubation days 14, 16 and 18 (40% O2) or 10, 12, 14, 16 and 18 (70% O2). Embryos incubated in 40% O2 displayed a pattern of growth enhancement similar to that previously reported for 60% O2. Accelerated embryonic growth was maintained through day 18. The heart showed the greatest percentage increase in weight over control, exceeding that of the whole embryo on days 16 and 18. The brain displayed significant enhancement only on day 16. Weight of the liver was unaffected by hyperoxia. Embryos in 70% O2 exhibited accelerated growth in all of the tissues examined early in incubation. Growth rate of the hyperoxic embryos then declined, so that embryo weight on day 18 did not differ from control. The brain, heart, eye, and proventriculus plus gizzard from 70% O2 embryos weighed significantly less than controls on day 18. Growth inhibition was most striking in the heart; heart/body weight ratio of 70% O2 embryos was significantly less than control throughout the observation period. The results confirm the growth accelerative effect of oxygen and suggest that the degree of growth enhancement is proportional to the ambient oxygen concentration. Accelerated growth cannot be maintained, however, in 70% O2.

Animals↗

PubMed1991

Progesterone metabolism during storage of blood samples from Gyr cattle: effects of anticoagulant, time and temperature of incubation.

Ten Gyr cows with a functional corpus luteum were used to evaluate the effects of time and temperature of incubation of blood samples on progesterone (P4) concentrations detected in plasma or serum. From each cow, a blood sample was collected into a flask containing no anticoagulant, another into an heparinized flask and a third into a flask containing sodium fluoride. The blood from each flask was divided into 46 aliquots. One of them was centrifuged within 5 min of collection. The remaining 45 aliquots were divided into three groups and kept at three different temperatures: 4 degrees C, 17 degrees C, or 37 degrees C. For each anticoagulant, aliquots from every cow and incubation temperature were centrifuged every 30 min for 6 h, and then at 8, 12 and 24 h. Plasma or serum were separated immediately after centrifugation and were kept frozen at -20 degrees C until assayed for progesterone. The mean initial concentration of P4 in serum (8.3 ng/ml) significantly diminished (P<0.05) to 6.7 ng/ml after 5 h of incubation at 4 degrees C, 3 h at 17 degrees C, or 2 h at 37 degrees C. In plasma from heparinized blood the initial concentration (7.8 ng/ml) declined significantly after 6 h of incubation at 4 degrees C, 2 h at 17 degrees C, or 1 h at 37 degrees C. Sodium fluoride used as anticoagulant prevented the degradation of P4 since the initial concentration of P4 (6.7 ng/ml) never declined during incubation at either 4 degrees C or 37 degrees C; the only significant reduction occurred after 24 h of incubation at 17 degrees C.

Journal Article↗

PubMed1990

Standard plate counts of drinking water: a comparison between incubation temperatures of 20 and 30 degrees C.

Standard plate counts of 5085 drinking water samples gathered in the Region of Basle were carried out over a period of 9 years (1977 to 1985). Two conditions of incubation were evaluated: 20 degrees C and 30 degrees C for 72 h. In ground water samples (3048 samples) colony forming units (cfu) at 30 degrees C were found to be higher than counts at 20 degrees C incubation, 45% of the samples contained greater than or equal to 2 cfu/ml at 30 degrees versus 35% at 20 degrees C. The median was 1 cfu/ml at both temperatures. In spring water samples (2036 samples) bacterial counts at 20 degrees C were found to be higher than counts at 30 degrees C incubation, 61% of the samples contained greater than 10 cfu/ml at 20 degrees C versus 51% at 30 degrees C. The median was 19 cfu/ml at 20 degrees C incubation versus 11 cfu/ml at 30 degrees C. These differences were statistically significant with p less than 0.001 (Wilcoxon matched-pairs signed-rank test). No correlation was found between bacterial counts at 20 degrees C and bacterial counts at 30 degrees C, nor between bacterial counts and original water temperatures. It appears that incubation temperatures of 20 degrees C and 30 degrees C favor the growth of different populations of bacteria and temperature is not the only factor. However, from a practical point of view the use of only one incubation temperature seems to be justified for the purpose of judging the sanitary quality of drinking water.

Bacteria↗

PubMed1988

A technique for the in vitro incubation of deer antler tissue.

1. A procedure for the in vitro incubation of velvet deer antler tissue was developed. Biopsy samples were collected in June with a trephine from 2 adult white-tailed deer and incubated in modified BGJb medium up to 48 hr. Calcium (Ca) and hydroxyproline (OH-proline) concentrations in the tissue were determined. 2. A significant increase (P less than 0.05) in Ca was exhibited at 4 and 8 hr of incubation, and, after replenishment of media, at 48 hr. 3. Hydroxyproline concentrations continued to rise throughout the duration of the incubation period and were significantly higher than controls (P less than 0.05) at 16, 24, and 48 hr. 4. Results suggest antler tissue can be incubated in vitro with the protocol described, although length of incubation may vary with parameter measured.

Animals↗

PubMed1994

Changes in tyrosine hydroxylase activity and melatonin synthesis in rat pineal glands throughout 72 hours of incubation.

Time-dependent modifications of N-acetyltransferase (NAT) activity, melatonin content, and tyrosine hydroxylase (TH) activity within the isolated rat pineal over a 72 h of incubation period were studied. Both pineal NAT activity and melatonin content displayed similar decreases after 12 h of incubation, and reached a maximal reduction of 82% or 93%, respectively, after 48 h. However, a maximal decrease of pineal TH activity was only 47% after 72 h of incubation. Neither the nuclear area of pinealocytes, nor lactate dehydrogenase (LDH) activity in the incubation medium showed any significant variation dependent on the incubation time. Treatment with isoproterenol caused an expected elevation of NAT activity and melatonin content but was unable to modify TH activity. Since a significant degree of pineal TH activity remained following 3 days of incubation, a non-sympathetic source of TH within the rat pineal gland is suggested.

Acetyltransferases↗

PubMed1983

The early events of infection with Theileria parva in cattle: infectivity for cattle of leukocytes incubated in vitro with sporozoites.

Leukocytes were isolated from bovine blood and, after short periods of incubation in vitro with sporozoites of Theileria parva, were washed thoroughly, and their infectivity tested in autologous and allogeneic hosts. Using a standard inoculum of 10(6) viable cells, it was found that, after incubation in vitro for either 1 or 24 h, the cells initiated lethal infections in autologous cattle, but failed to infect allogeneic animals. Autologous and allogeneic erythrocytes and mouse lymphocytes similarly incubated with sporozoites failed to infect cattle. The supernatant from bovine lymphocyte suspensions incubated with sporozoites for 1 h produced lethal infections whereas after 24 h of incubation the supernatant was non-infective. All cattle which did not develop detectable infection were fully susceptible to subsequent challenge with a stabilate of sporozoites. By inoculating cattle with graded doses of autologous blood leukocytes which had been incubated for 24 h with sporozoites, it was found that as few as 2 X 10(3) cells gave rise to infection. The results indicate that this approach can be used to evaluate different cell populations as targets for infection and transformation by sporozoites of T. parva.

Animals↗

PubMed1990

A drug incubation infectivity test (DIIT) for assessing resistance in trypanosomes.

Blood stream forms of drug-resistant and sensitive Trypanosoma brucei brucei, Trypanosoma brucei evansi and Trypanosoma vivax were incubated in a liquid medium for 24 h at 37 degrees C in the presence of various concentrations of diminazene aceturate (Berenil) or isometamidium chloride (Samorin), and assayed for infectivity in mice. Whereas the infectivity to mice of all Samorin-sensitive trypanosomes was decreased after incubation with 1 ng Samorin ml-1, the Samorin-resistant stocks remained infective for mice. Two of the Samorin-resistant stocks remained infective after incubation with Samorin concentrations of up to 50 ng ml-1. The infectivity of Berenil-resistant trypanosome stocks were also retained after incubation with drug concentrations (0.5 or 1.0 micrograms ml-1) which otherwise inhibited the infectivity of Berenil-sensitive trypanosome stocks. In addition, differences in infectivity were observed when Berenil-resistant and sensitive trypanosome stocks were incubated in medium supplemented with serum from goats previously treated with Berenil. Thus, drug-resistant and sensitive trypanosomes can be clearly distinguished using the drug incubation infectivity test.

Amidines↗

PubMed1996

The effects of phosphate- and substrate-free incubation conditions on glycolysis in Ehrlich ascites tumour cells.

The influence of phosphate-free medium buffered with synthetic organic buffers, and of a preliminary incubation of cells in medium lacking added substrate ('pre-incubation') was investigated with mouse-cultured Ehrlich ascites tumour cells. In comparison to phosphate-containing bicarbonate-buffered balanced-salts medium, organic-buffered medium, without a preliminary substrate-free pre-incubation, was associated with 20-30% reduction in the rate of glycolysis, the 3- to 4-fold accumulation of fructose 1,6-bisphosphate and the halving of both ATP and total adenine nucleotide levels. These perturbations were reversed by the inclusion of 5 mM sodium phosphate in the organic-buffered medium. Pre-incubation for up to 90 min, before inclusion of glucose, resulted in greater depression of the glycolytic rate and concentrations of adenine nucleotides. This occurred in both the balanced-salts medium and the organic-buffered medium. During pre-incubation cells were lysed, releasing lactate dehydrogenase, when physically agitated too vigorously. It was concluded that the use of phosphate-free medium and pre-incubation are not advisable procedures for routine metabolic investigations with this cell line.

Animals↗

PubMed2006

Behavioral variation and its consequences during incubation for American kestrels exposed to polychlorinated biphenyls.

We investigated whether polychlorinated biphenyl (PCB) exposure in American kestrels (Falco sparverius) influenced incubation behavior and whether altered behavior could lead to poor reproductive success. Captive kestrels were fed a mixture of PCBs (Aroclors 1248:1254:1260) at an approximate daily dose of 7 mg/kg body weight, 1 month prior to pairing and throughout incubation. Behaviors of 23 control and 23 PCB-exposed pairs were monitored throughout incubation using an electronic balance in the nest box. PCB exposure resulted in longer incubation periods and in altered incubation behaviors. Seven of 14 behavioral variables showed some association with treatment, with sex-specific effects largely biased toward disrupted male behavior. For most behaviors, the treatment effect was explained by the delayed clutch initiation induced by PCBs rather than by a direct physiological impact of the contaminants. PCB-exposed pairs with greater attendance to their eggs and better coordination of incubation duties had improved hatching success.

Animals↗

PubMed2005

Apoptosis of HeLa cell lines incubated with retinol.

PURPOSE: The aim of the study was to evaluate a soluble form of APO-1/Fas antigen in supernatants from HeLa cell line culture after 24 and 72 h of incubation with selected retinoic acid concentrations. MATERIALS AND METHODS: HPV18-positive cell lines were cultivated with All-trans-retinoic acid (ATRA) at concentrations of 1 x 10(-6) and 1 x 10(-9) M. The cultures were incubated for 24 and 72 h. A control culture with 3 microl of DMSO was incubated under identical conditions. The concentrations of soluble APO-1/Fas antigen in cell culture supernatants were estimated using an ELISA method. RESULTS: The culture with 72-h incubation with retinoic acid proved to be toxic to cells and was excluded from the analysis. The results obtained showed a significantly lower concentrations of soluble APO-1/Fas antigen in supernatants from cell lines incubated with retinol for 24 h than in the controls. CONCLUSIONS: The higher concentrations of soluble APO-1/Fas antigen in supernatants from the HeLa cell line without retinol may constitute a protective mechanism of the cells infected with the virus before undergoing Fas/FasL-dependent apoptosis. Lower concentrations of sAPO-1/Fas antigen in the supernatant from HeLa cell culture incubated with retinol may suggest that mechanisms protecting infected cells against Fas/FasL-mediated apoptosis become defective under the influence of retinol. Our studies confirm that Vitamin A and its analogues inhibit the proliferation of cells associated with HPV infection and suggest promising effects of retinoid therapy in inhibiting the progression of early cervical lesions to cancer.

Antineoplastic Agents↗

PubMed2004

Incubation of rat aortic rings produces a specific reduction in agonist-evoked contraction: effect of age of donor.

We studied the effect of age on the response of aortic rings to injury produced by three days' incubation, and the mechanism of this response. Five-mm rings of the thoracic aorta isolated from Wistar rats were incubated or not in culture medium. Isometric contraction evoked by agonists (norepinephrine or serotonin) or high [K(+)](e) was determined in the presence and absence of endothelium. Experiments were repeated in the presence of propranolol (0.3 microM), polymixin B (36 microM), pyrrolidine dithiocarbamate (50 microM) or glutathione (3 mM). Inductible NO-synthase and cyclo-oxygenase-2 mRNA were determined by real-time PCR, and glutathione-related enzymes and catalase activity by spectrophotometry. Incubation reduced the isometric contraction evoked by agonists but not by high [K(+)](e). The reduction in agonist-evoked contraction was greater in rings from adult (norepinephrine Emax-80%) than in young (-40%) rats. The removal of the endothelium had no effect. The reduction in norepinephrine-evoked contraction was not due to endotoxin contamination, beta-adrenoceptor-mediated dilation or any change in ring structure (no fibrosis or edema). Inductible NO-synthase (but not cyclo-oxygenase-2) mRNA increased on incubation. N(G)-nitro-L-arginine methyl ester partially restored contractility in rings from adult animals, further addition of an anti-oxidant restored norepinephrine-evoked contraction. Catalase fell with age and glutathione reductase increased upon incubation in rings from young donors only. In conclusion, incubation of the aorta produces a specific reduction in agonist-evoked contraction that involves induction of smooth muscle cell oxidative stress and iNOS. The reaction is greater in rings from older animals.

Age Factors↗