Showing papers on "Incubation published in 2004"
TL;DR: This result suggests that S plays a critical role in the mediation of H 2 evolution from P. subcordiformis, and strongly depended upon the duration of anaerobic incubation, deprivation of sulphur (S) from the medium and the medium pH.
172 citations
TL;DR: Results demonstrated that the mode of cell death was dependent on the ion concentration and the incubation time, and the noninflammatory process of apoptosis was predominant at short incubation times, however, necrosis was dominant at higher ion concentrations.
Abstract: There has been a renewed interest in the use of the metal-on-metal (MOM) implants for total hip arthroplasty (THA). It is well known, however, that the MOM articulation generates both metal particles and ions. The physiologic effects of these ions are poorly understood and their potential toxicity remains a cause for concern. In the present study, murine J774 macrophages were incubated with Co2+ and Cr3+ ions and the mode of cell death (apoptosis/necrosis) was evaluated in vitro by transmission electron microscopy and cell death ELISA. Overall, results demonstrated that the mode of cell death was dependent on the ion concentration and the incubation time. Indeed, at short incubation times (24h), the noninflammatory process of apoptosis was predominant. At longer incubation times (48h), however, necrosis was predominant at higher ion concentrations.
118 citations
TL;DR: The data suggest that, with the exception of certain genes induced by tissue injury, relative quantification of mRNA, even on degraded RNA samples, can provide a reliable estimate of in vivo mRNA levels.
82 citations
TL;DR: Despite the adoption of behavioural solutions to face heavy heat loads, nesting success was vulnerable to these solutions because heat stress during extended periods may constrain parental nest attendance, and this may limit the opportunities for sexual conflicts over incubation.
Abstract: Biparental incubation is frequent among shorebirds and is expected when the survival prospects of offspring increase relative to uniparental incubation. To understand why this occurs, it is important to identify the factors that constrain uniparental incubation. It is assumed that birds choose nesting sites that provide an appropriate microclimate for incubation. Many shorebirds nest in sites with no or little cover, where ambient temperatures at ground level might be >50°C during very hot days. Shorebirds nest in exposed sites because predation risk on incubating adults is higher in covered sites. In hot environments, incubating shorebirds might experience heat stress in exposed sites, and this may compromise nesting success if adults are unable to attend their nests continuously, limiting the possibilities of uniparental incubation and thus the expression of a sexual conflict over incubation. The operative temperatures of Kentish plovers (Charadrius alexandrinus) were recorded in exposed and covered sites, and the thermal behaviour and incubating tactics of pair members were studied in a hot environment. During the hottest part of the day, there was a difference of 10–15°C in the operative temperatures of plovers between covered and exposed sites. Plovers in covered sites did not exhibit any thermoregulatory behaviour indicative of thermal stress, probably because the thermal range encountered by them in such places during most of the daytime was close to the thermo-neutral zone. The frequency with which plovers in exposed sites exhibited thermoregulatory behaviour was related to ambient temperature. Under very hot conditions, incubating birds were probably unable to maintain homeostasis for long periods and pair members resorted to shortening incubation bouts. Female Kentish plovers mainly incubate in the daytime and males during the night. However, the probability of diurnal incubation by males increased with ambient temperature in exposed nests, but not in covered ones. In fact, the frequency of participation in diurnal incubation by males was greater in exposed than in covered sites, suggesting that the participation of males in diurnal incubation may be related to the inability of females to stay at the nest during long periods when the ambient temperature is high. Even after resorting to shortened incubation bouts, the plovers may be unable to attend their nests continuously during heat waves, and the nests may be deserted. The propensity of plovers to desert their nests was affected by proximity to water, with nests located close to water being deserted less frequently. It seems likely that susceptibility to thermal stress changed in relation to proximity to water because in sites close to water it was possible to belly-soak, which would allow a more continuous nest attendance. Therefore, despite the adoption of behavioural solutions to face heavy heat loads, nesting success was vulnerable to these solutions because heat stress during extended periods may constrain parental nest attendance, and this may limit the opportunities for sexual conflicts over incubation.
78 citations
TL;DR: Seasonal shifts in incubation temperatures are widespread, and may generate important variation in hatchling phenotypes, which may influence phenomena such as nest-site selection, the seasonal timing of nesting, and the evolution of viviparity.
Abstract: Summary
1The thermal regimes experienced by a reptilian egg can influence phenotypic traits (size, sex, shape, locomotor performance, etc.) of the hatchling that emerges from that egg. Natural nests of the oviparous scincid lizard Bassiana duperreyi in the Brindabella Range of south-eastern Australia show strong seasonal shifts in temperature: first and last weeks of incubation often differ by >5 °C.
2Eggs of B. duperreyi were incubated under thermal regimes with identical overall mean values for average temperature and diel range, but differing in the sequence of temperatures. Some eggs were kept at 18 ± 5 °C throughout incubation; others went gradually from cool (16 ± 5 °C) to warm (20 ± 5 °C); and others from warm (20 ± 5 °C) to cool (16 ± 5 °C).
3These treatments significantly modified not only incubation periods (stable mean temperatures delayed hatching), but also hatchling traits: progressively decreasing temperatures yielded hatchlings with a higher incidence of deformities, smaller body size, relatively longer tails, and reduced locomotor performance than siblings from increasing temperatures.
4Seasonal shifts in incubation temperatures are widespread, and may generate important variation in hatchling phenotypes. Sensitivity to such shifts may influence phenomena such as nest-site selection, the seasonal timing of nesting, and the evolution of viviparity.
74 citations
TL;DR: It is suggested that the social context influences singing behavior to a varying degree across the season, and that this variation also depends on time of day.
Abstract: Seasonal patterns of singing activity of male birds have been thoroughly studied, but little is known about how those patterns vary with time of day. Here, we censused mated and unmated male Nightingales (Luscinia megarhynchos) at four different hours of the day throughout the breeding cycle. In unmated males, singing activity increased until the young hatched in their neighborhood, and the seasonal variation was similar at each of the four hours of the day. In mated males, however, the seasonal patterns of singing activity differed between hours of the day. In morning (about the hour of egg-laying) and during the dusk chorus, the singing activity of mated males was strongly influenced by the females' reproductive state: singing activity was low before egg-laying and during incubation, but high during the egg-laying period. In the dawn chorus, however, singing activity showed a similar seasonal pattern in mated and unmated males and was high until late stages of the breeding cycle. Our results suggest that the social context influences singing behavior to a varying degree across the season, and that this variation also depends on time of day. The hour of data collection thus is an important but often neglected factor when seasonal changes of singing activity are studied.
74 citations
TL;DR: It is demonstrated that even in a strictly monogamous songbird with biparental incubation, all forms of paternal care remain sensitive to elevated plasma testosterone, suggesting a shift from parental effort to mating effort.
72 citations
TL;DR: The genetic make-up of birds influenced the physical dimensions and eggshell characteristics of their eggs and these differences in the characteristics of hatching eggs influenced embryonic growth and HP when incubated under light.
Abstract: 1. Eggs from two layer-type breeder flocks (ISA-W vs Leghorn) between 30 and 45 weeks of age were used in 4 trials to study the effects of lighted incubation on embryonic growth from 5 to 18 d of age and hatchability per cent (HP). The physical dimensions, eggshell characteristics and conductance (EC) of eggs of the two strains were compared. 2. Eggs were set in an incubator on trays either in the dark-control or under two tubes of 20-watt white fluorescent light during the first 18 d of incubation. The light intensity ranged from 1230 to 1790 lux at the surface of the eggs. Eggs were transferred to dark hatching compartments at d 19 of incubation. 3. The genetic make-up of birds influenced the physical dimensions and eggshell characteristics of eggs. ISA-W eggs had higher weight, surface area (ESA), volume (EV), width, EC, shell volume and HP, and lower ESA:EV ratio, per cent shell, shell density and dead embryos than those of Leghorn eggs. 4. Lighted incubation increased daily embryonic growth (mg/d) and HP by 3.9 and 5.9%, respectively, when compared with the dark-control incubation. 5. The physical dimensions and eggshell characteristics of eggs influenced the effects of lighted incubation on embryonic growth and HP. Lighted incubation increased embryonic growth and HP of ISA-W eggs. The increase in embryonic growth and HP of the Leghorn eggs was not significant. 6. The genetic make-up of birds influenced the physical dimensions and eggshell characteristics of their eggs and these differences in the characteristics of hatching eggs influenced embryonic growth and HP when incubated under light.
69 citations
TL;DR: It is demonstrated that cortisol plays an important role in the down-regulation of phagocytic but not of cytotoxic activity in seabream leucocytes.
69 citations
TL;DR: It is concluded that Cd2+ has a dual action in stable porcine granulosa cells: Low concentrations activate, whereas high concentrations inhibit, expression of the P450scc gene and progesterone synthesis.
Abstract: We investigated the effects of cadmium (Cd2+) on transcription of the cytochrome p450 side chain cleavage (p450scc) gene and on progesterone synthesis in stable granulosa cells. We used the stable porcine granulosa cell line, JC-410, genetically modified to express a luciferase genomic construct carrying 2320 base pairs (bp) of the p450scc gene promoter (p450scc-2320-LUC). A construct containing only the luciferase gene, pOLUC, was used as a promoterless control. At 1 microM, cadmium chloride (CdCl2) increased transient expression of p450scc-2320-LUC in JC-410 cells by 2.6-fold after 24-h incubation. A similar pattern of stimulation by CdCl2 was observed in cells transiently transfected with a luciferase genomic construct carrying 100 bp of the p450scc gene promoter p450scc-100-LUC, whereas no stimulation by CdCl2 was observed in cells transfected with pOLUC. At 0.6, 1, and 2 microM, CdCl2 stimulated the activity of the p450scc-2320-LUC promoter in a dose-related fashion by 1.58-, 3.19-, and 2.67-fold, respectively, after 24-h incubation. Northern blot analysis showed that CdCl2 at 0.1, 1, 2, and 3 microM increased p450scc mRNA levels by 3.13-, 1.38-, 1.61-, and 1.57-fold, respectively, after 24-h incubation. After 48-h incubation, CdCl2 at 0.6, 1, and 2 microM further increased p450scc mRNA levels by 3.43-, 2.08-, and 2.4-fold, respectively. At 1, 2, and 3 microM, CdCl2 inhibited progesterone synthesis to 0.48-, 0.38-, and 0.29-fold, respectively. After 48-h incubation, CdCl2 at 0.1 microM stimulated progesterone synthesis by 1.6-fold. We conclude that Cd2+ has a dual action in stable porcine granulosa cells: Low concentrations activate, whereas high concentrations inhibit, expression of the p450scc gene and progesterone synthesis. The stimulatory effect of Cd2+ appears to be mediated via a cis-acting element located 100 bp upstream of the p450scc gene transcription start site.
TL;DR: While hypothermic incubation does not affect gross development (other than would be predicted from a simple effect of Q10), there is a significant delay in the relative timing of the onset of thermoregulatory ability induced by hypotheric incubation.
Abstract: Chronic exposure to a low incubation temperature clearly slows the development of poikilothemic chicken embryos (or any other poikilotherms), but little is known about the more subtle developmental effects of temperature, especially on physiological regulatory systems. Consequently, two populations of chicken embryos were incubated at 38 degrees C and 35 degrees C. When compared at the same development stage, incubation temperature had no significant impact on embryonic survival or growth. Moreover, the relative timing of major developmental landmarks (e.g. internal pipping), expressed as a percentage of development, was unaffected by temperature. The ability to maintain the rate of oxygen consumption ((O(2))) during an acute drop in ambient temperature (T(a)) improved from Hamburger-Hamilton (HH) stages 39-40 to 43-44 in the 38 degrees C but not the 35 degrees C populations. Late stage (HH43-44) embryos incubated at 38 degrees C could maintain (O(2)) (approximately 27-33 micro l g(-1) min(-1)) during an acute drop in T(a) to approximately 30 degrees C. However, at the same stage 35 degrees C embryos acutely measured at 38 degrees C were unable to similarly maintain their (O(2)), which fell as soon as T(a) reached 36 degrees C. Thus, while hypothermic incubation does not affect gross development (other than would be predicted from a simple effect of Q(10)), there is a significant delay in the relative timing of the onset of thermoregulatory ability induced by hypothermic incubation.
TL;DR: Manipulating the incubation temperature for 4 d in early incubation alters muscle development in the turkey with no observation of deformities or reduction in hatchability, and it is speculated that this increase in temperature may result in an improved muscle growth in the post-hatch bird.
Abstract: 1. The effect of manipulating egg incubation temperature for short periods on turkey muscle development was determined using the M. semitendinosus, a thigh muscle, as the model. 2. Experiment 1. Eggs were incubated at a control temperature of 37·5°C. For a 4-d period of 0 to 4, 5 to 8, 9 to 12, 13 to 16, 17 to 20 or 21 to 24 embryonic days (ED) eggs were transferred to either 38·5 or 35·5°C. A regime of 38·5°C at 5 to 8 and 9 to 12 ED caused an increased myonuclei number and muscle fibre number, respectively. 3. Experiment 2. Eggs were incubated at a control temperature of 37·5°C. At 5 to 8 ED eggs were transferred to 38·5 or 35·5°C. Temperature-manipulated embryos showed a delay in differentiation (myogenin expression) of the semitendinosus muscle compared to controls. 4. Manipulating the incubation temperature for 4 d in early incubation alters muscle development in the turkey with no observation of deformities or reduction in hatchability. We speculate that this increase in temperature may result in an...
TL;DR: The results do not support the hypothesis that longer incubation periods are caused by reduced nest attentiveness and corresponding lower Tegg.
Abstract: The wide range in incubation periods among bird species has puzzled biologists for decades, because an extended egg-phase increases time-dependent mortality of the eggs. We investigated a recently proposed mechanistic explanation inspired by life-history theory, suggesting that adults may increase their own survival by reducing nest attentiveness, the percentage of daytime spent incubating eggs, in exchange for reduced offspring (egg) survival due to a longer incubation period. Incubation behaviour and egg temperatures (Tegg) of 14 bird species in the humid lowland tropics were studied to test the hypothesis that lower nest attentiveness and reduced Tegg cause longer incubation periods. Increased nest attentiveness correlated with higher average Tegg. However, neither nest attentiveness nor average Tegg was associated with the length of the incubation period. Longer off-bouts resulted in lower Tegg, but neither number of off-bouts nor off-bout length was associated with incubation period. In addition, we reanalysed a previously published negative association between Tegg and incubation period based on literature data from temperate passerine birds using a larger data set and found no significant correlation. In conclusion, our results do not support the hypothesis that longer incubation periods are caused by reduced nest attentiveness and corresponding lower Tegg.
TL;DR: The transport of Sr differs from the transport of such heavy metals, as Cd, Pb, and Ni, and is similar in many aspects to the distribution of calcium, another alkaline earth metal, probably due to similar physical and chemical properties of their ions.
Abstract: Two-day-old seedlings of maize (Zea mays L.) were incubated on 3 mM and 35 μM solutions of Sr(NO3)2, and the toxic effects of strontium were assessed by measuring, in the course of four days of incubation, the daily increments of the primary root length and also the root and shoot length by day 7 of incubation, and the length of the fully elongated cells. Sodium rhodizonate, a reagent developing the colored complex with Sr, was used to follow Sr distribution in maize tissues and organs following 2, 24, 48, and 168 h of incubation. Sr was found in all root tissues as soon as after 24 h of incubation; it accumulated mostly in the cell apoplast, whereas its content in the protoplasts was considerably lower. Strontium readily crossed the endodermal barrier via the symplast and was immobilized predominantly in the pericycle cell walls; therefore, it did not hamper root branching. Strontium did not affect the final cell length and hindered root growth (at the concentration of 3 mM) by inhibiting cell division. In the shoots, Sr was found in the xylem cell walls in the vascular bundles of coleoptile, mesocotyl, and leaves on the second day of incubation, an evidence for high Sr mobility. We conclude that the transport of Sr differs from the transport of such heavy metals, as Cd, Pb, and Ni, and is similar in many aspects to the distribution of calcium, another alkaline earth metal, probably due to similar physical and chemical properties of their ions.
TL;DR: Evidence from size patterns of tuatara incubated in natural nests supports differential fitness models for the adaptive significance of temperature-dependent sex determination in tuataras.
Abstract: The size of reptile hatchlings can be phenotypically plastic in response to incubation temperature, and size is a trait likely to influence fitness – i.e. hatchling size is proposed as an indicator of quality. The parental and incubation temperature effects on the size of one of New Zealand's most biologically significant reptile species, the tuatara Sphenodon punctatus are investigated. Artificial incubation at constant temperatures is used to produce founders for new captive and wild populations of tuatara and to augment existing rare populations. We compare size of hatchling tuatara from artificial and natural incubation treatments. The relationship of hatchling size with incubation temperature and sex is examined, and we investigate whether our results support differential fitness models for the evolution of temperature-dependent sex determination in tuatara. Initial egg mass is the most important factor affecting size of hatchling tuatara and is still an important influence at 10 months of age. Incubation temperature does not greatly influence size of hatchlings, but significantly influences size by 10 months of age. Constant artificial incubation conditions result in larger, but possibly less aggressive, juveniles than those from more variable natural incubation conditions by 10 months of age. Evidence from size patterns of tuatara incubated in natural nests supports differential fitness models for the adaptive significance of temperature-dependent sex determination. Thermal variation has little effect on size of male hatchlings, but female embryos that develop in more stable thermal conditions, in more reliable sites for hatching, are bigger and have longer jaws.
TL;DR: The data suggest that the restricted northern distribution of O. suteri results from ecological constraints caused by the negative effects of cool incubation temperatures on embryos and subsequently hatchlings.
Abstract: Reptile eggs from cool temperate environments often experience cool incubation conditions, which may have long-term consequences for individual fitness. We studied the effects of artificial incubation regimes on size, growth, and survival of New Zealand's only endemic oviparous lizard, Oligosoma suteri. Eggs were randomly distributed among three incubation temperatures (18, 22, 26 C) and two water potentials (−120 and −270 kPa). Hatchlings incubated at 22 C and −120 kPa were significantly larger for most measurements than hatchlings from other incubation treatments. Juveniles from the two higher incubation temperatures had more rapid growth and ultimately greater size by 12 months, as well as significantly higher survival to 18 months, than did 18 C incubated individuals. Hatchling size did not influence survival. Our data suggest that the restricted northern distribution of O. suteri results from ecological constraints caused by the negative effects of cool incubation temperatures on embryos and...
TL;DR: Assessment of photoinduced toxicity of hypericin in PAM 212 murine keratinocytes and the relationship between concentration, incubation time and light fluence to evaluate the effect of intracellular aggregation at high concentrations found there was a pronounced aggregation effect at 50 μM.
Abstract: We have assessed photoinduced toxicity of hypericin in PAM 212 murine keratinocytes and the relationship between concentration, incubation time and light fluence to evaluate the effect of intracellular aggregation at high concentrations Confocal microscopy was used to establish the subcellular localization of hypericin at 5 and 50 μM and incubation times of 1 and 3 h From fluorescence uptake time course studies, intracellular hypericin was demonstrated to exist predominantly in the monomeric form for up to 26 h incubation at 5 μM However, there was a pronounced aggregation effect at 50 μM, with intracellular hypericin fluorescence levels initially showing an increase followed by a decrease with incubation time This effect was subsequently shown to exert an effect on the phototoxicity of hypericin On irradiation, the photocytotoxicity for 1 and 7 h incubation with 50 μM hypericin was comparable, whereas using 5 μM the photocytotoxicity showed good correlation with the intracellular fluorescence measurements at 1 and 7 h incubation
TL;DR: Isolation of the eggs was advantageous for the overall hatching success and makes egg bank diversity analyses less time consuming, and isolation reduced such inter-specific differences so that even very short incubation periods kept bias within acceptable limits.
Abstract: Zooplankton resting egg banks accumulate resting stages of various zooplankton species that are active in different habitats and different periods of the year. As such, hatching of resting eggs from lake sediments may potentially be very useful in zooplankton diversity studies. In this study, we tested whether the efficiency of the cost-effective technique is increased by isolating the resting eggs from the sediment prior to incubation. Isolation of the eggs was advantageous for the overall hatching success (+26% after 36 days of incubation compared to incubation of sediment). Furthermore, isolation of resting eggs makes egg bank diversity analyses less time consuming in two ways. (1) It reduced the time needed for the eggs to hatch with on average 35%. In the isolation treatment all responsive resting eggs hatched within the first 4 weeks of incubation, while in the non-isolation treatment neither the cumulative number of macrozooplankton hatchlings nor the cumulative number of hatched cladoceran species levelled off after 36 days of incubation. (2) In contrast to the non-isolation treatment, where large differences occurred between taxa in incubation time, isolation reduced such inter-specific differences, so that even very short incubation periods kept bias within acceptable limits.
TL;DR: No clear effect of VA status or incubation temperature could be found on the formation of the early vertebral column although Atlantic salmon fry incubated at low temperatures had less regular constrictions of the prospective vertebralcolumn than fry incubation at high temperatures.
Abstract: The effect of egg vitamin A (VA) status and egg incubation temperature on the development of spinal disorders was investigated in Atlantic salmon Salmo salar fry. Atlantic salmon eggs were sorted into two groups with high VA (3·3 ± 0·1 μg retinol g−1 dry mass) and low VA (2·2 ± 0·3 μg retinol g−1 dry mass) status before fertilization and incubated at high (14° C) or low (8° C) temperature from 133 day degrees until the onset of feeding. High egg incubation temperatures increased the concentration of retinol in the eggs: the high VA and high temperature group displayed a significantly higher retinol concentration than the high VA and low temperature group (P = 0·001). After hatching, all experimental groups increased their retinol concentration. The source of the increased retinol levels was probably retinal, although astaxanthin may also be a VA precursor after hatching. Atlantic salmon fry incubated at high temperatures had increased amounts of notochord tissue. When measuring morphogenic activity in the notochord using the expression of sonic hedgehog (shh, mRNA), however, no significant difference was found between the experimental groups. No clear effect of VA status or incubation temperature could be found on the formation of the early vertebral column although Atlantic salmon fry incubated at low temperatures had less regular constrictions of the prospective vertebral column than fry incubated at high temperatures.
TL;DR: The time elapsed from the start of the cooking process to the consumption of school and nursery school lunches was significantly shorter than at other cooking facilities, suggesting limited bacterial growth, which in turn is thought to lead to a long incubation period.
TL;DR: The present findings indicate that the detrimental effect of high temperature on reproductive performance may not be related to the elevated PRL levels in heat-stressed birds but to mechanism(s) that involve 5-HT neurotransmission and the induction of hyperthermia.
Abstract: Reproductive failure associated with heat stress is a wellknown phenomenon in avian species. Increased prolactin (PRL) levels in response to heat stress have been suggested as a mechanism involved in this reproductive malfunction. To test this hypothesis, laying female turkeys were subjected to 408C for 12 h during the photo-phase daily or maintained at 24‐268C. Birds in each group received oral treatment with parachlorophenyalanine (PCPA; 50 mg/kg BW/day for 3 days), an inhibitor of serotonin (5-HT) biosynthesis, or immunized against vasoactive intestinal peptide (VIP). Both treatments are known to reduce circulating PRL levels. Nontreated birds were included as controls. In the control group, high ambient temperature terminated egg laying, induced ovarian regression, reduced plasma luteinizing hormone (LH) and ovarian steroids (progesterone, testosterone, estradiol) levels, and increased plasma PRL levels and the incidence of incubation behavior. Pretreatment with PCPA reduced (P , 0.05) heat stress-induced decline in egg production, increase in PRL levels, and expression of incubation behavior. Plasma LH and ovarian steroid levels of heat stressed birds were restored to that of controls by PCPA treatment. As in PCPA-treated birds, VIP immunoneutralization of heat-stressed turkeys reduced (P , 0.05) circulating PRL levels and prevented the expression of incubation behavior. But it did not restore the decline in LH, ovarian steroids, and egg production (P . 0.05). The present findings indicate that the detrimental effect of high temperature on reproductive performance may not be related to the elevated PRL levels in heat-stressed birds but to mechanism(s) that involve 5-HT neurotransmission and the induction of hyperthermia. birds, egg production, heat stress, incubation behavior, luteinizing hormone, ovary, pituitary hormones, prolactin, reproduction, reproductive hormones, serotonin, stress, turkeys, vasoactive intestinal peptide
TL;DR: The results of one-way anova in 4-day LD50 test showed that incubation salinity significantly affected virulence, and E. tarda had a faster proliferation rate than that at 10 g L−1.
Abstract: Experiments were designed to determine the effects of temperature and salinity on the virulence of Edwardsiella tarda to Japanese flounder, Paralichthys olivaceus. In the temperature experiment, a two-factor design was conducted to evaluate the effects of both pathogen incubation temperature and fish cultivation temperature on pathogen virulence. E. tarda was incubated at 15, 20, 25 and 30±1°C, and the fish (mean weight: 10 g) were reared at 15, 20 and 25±1°C respectively. The fish reared at different temperatures were infected with the E. tarda incubated at different temperatures. The results of a 4-day LD50 test showed that temperature significantly affected the virulence of E. tarda (P<0.01) and the interaction between the two factors was also significant (P<0.01). For fish reared at 15°C the virulence of E. tarda was the highest at 25°C of pathogen incubation, followed by 20, 15 and 30°C. When the fish rearing temperature was raised to 20 and 25°C, the virulence of E. tarda incubated at all temperatures increased. Isolation testing demonstrated results similar to those of LD50. The higher rearing temperature increased the proliferation rate of the pathogen in fish. In the salinity experiment, the incubation salinity of E. tarda was at 0, 10, 20 and 30 g L−1, respectively, and the fish with mean weight of 50 g were cultured in natural seawater of 30 g L−1. The results of one-way anova in 4-day LD50 test showed that incubation salinity significantly affected virulence. Virulence was lower when the salinity of the incubation medium was at 0 and 30 g L−1, higher at 10 and 20 g L−1. The results of isolation test were in accordance with those of LD50. At 20 g L−1E. tarda had a faster proliferation rate than that at 10 g L−1.
TL;DR: The degradation of As-sugar 1 in acidic solution was followed by (1)H-NMR, and the relative slow degradation suggests that arsenosugars are taken up from the stomach in their original chemical form, hence the study of arsenosugar incubation in tissue is highly relevant.
Abstract: It has been shown, that in vitro incubation of Laminaria digitata extract (containing mainly As-sugar 1 (glycerol-arsenoribose) and As-sugar 3 (sulfonate-arsenoribose)) with liver cytosol, produced the same two arsenicals, as when L. digitata extract was treated with H(2)S. By parallel use of HPLC-ICP-MS and HPLC-ES-MS the compounds displayed mainly m/z 345 and m/z 409. A pure As-sugar 1 standard was obtained, and a standard of arsinothioyl-sugar 1 (m/z 345) was produced, by purging a solution of As-sugar 1 with gaseous H(2)S. The identity of arsinothioyl-sugar 1 was characterised by ES-MS, 1D and 2D NMR. Arsinothioyl-sugar 1 showed the same chromatographic behaviour and MS characteristics as one of the two arsenic-containing compounds (m/z 345) produced by incubation of L. digitata extracts with liver cytosol, and as the product of the incubation of As-sugar 1 with liver cytosol (HPLC-ICP-MS, HPLC-ES-MS). Assuming that As-sugar 3 reacts in a similar way to As-sugar 1 with H(2)S, it is most likely that the second unknown (m/z 409) is arsinothioyl-sugar 3. The degradation of As-sugar 1 in acidic solution (100 mM HCl) was followed by (1)H-NMR, and the relative slow degradation (t(1/2)= 17 h) suggests that arsenosugars are taken up from the stomach in their original chemical form, hence the study of arsenosugar incubation in tissue is highly relevant. The arsinothioyls are a new group of organoarsenicals, which have only recently been identified in nature. Here, arsinothioyl sugars are detected for the first time. The in vitro formation of arsinothioyl-sugars in liver cytosol suggests that arsinothioyls may be of large biochemical and toxicological importance.
TL;DR: Of the enzyme activities studied, dehydrogenase and beta-glucosidase activities were the most sensitive to ridomil gold plus, and this sensitivity was more pronounced with the dehydrogen enzyme activity.
Abstract: The purpose of the study was to investigate changes of soil chemical and biological properties changes resulting from a single application of the fungicide Ridomil Gold plus copper (Ridomil Gold plus)(mefenoxam 6% + copper oxide 60%) at the following rates 0.25, 0.5, 1, 2, and 10 g m(-2). Selected chemical properties generally differed between fungicide rates over longer incubation periods. Microbial activity indices (available N, ammonification rates and specific enzymatic systems) were more sensitive indicators of change. Values of these indicators generally increased with incubation period and decreased or increased at high rates. Significant changes in P availability occurred after 90 days of incubation at rates > or = 1 g m(-2). Incorporation of the fungicide significantly increased NH4+ levels in soil after 75 days of incubation. These changes stimulated soil microbial activity as evidenced by increased ammonification rates especially at long-term exposure. Of the enzyme activities studied, dehydrogenase and beta-glucosidase activities were the most sensitive to ridomil gold plus. This sensitivity was more pronounced with the dehydrogenase activity.
TL;DR: To evaluate whether egg aggregation influences embryonic development, flexible-shelled Schreiber's green lizard eggs were incubated under three levels of soil water potential and under two levels of aggregation to find any effect of egg aggregation in embryonic development.
Abstract: Many oviparous terrestrial species deposit flexible-shelled eggs into the soil. These eggs are sensitive to the hydration level of the nest environment. Among other factors, water exchange of eggs during incubation may be affected by the soil water potential. To evaluate whether egg aggregation influences embryonic development, we incubated flexible-shelled Schreiber's green lizard (Lacerta schreiberi) eggs under three levels of soil water potential (wet: –150 kPa; intermediate: –650 kPa; dry: –1150 kPa) and under two levels of aggregation (aggregated: in groups of six eggs with physical contact among them; isolated: groups of six eggs each 1 cm apart). The availability of water during egg incubation influenced egg mass and hatchling size. Eggs incubated in dry soils absorbed less water and produced smaller hatchlings. The selected levels of soil water potential did not influence incubation duration or hatching success. When soil was wet or dry, we did not find any effect of egg aggregation in embryonic d...
Journal Article•
TL;DR: Typical TSE could be induced in hamsters by inoculating strain 263K in the five infection ways and the neuropathological changes and PrP(Sc) deposits seem to be related with regions and inoculating pathways.
TL;DR: It is demonstrated that factors other than incubation behavior can be important in establishing avian hatching patterns, and in mixed-sexed clutches in which the first-laid embryo is male, a faster development time of males should mean asynchronous hatching regardless of parental incubation regime.
Abstract: Competitive interactions among siblings are an important determinant of parental fitness. These are strongly influenced by relative offspring size and therefore also by the extent to which parents can influence offspring size hierarchies. The temporal pattern of hatching in an avian clutch has a large effect on size and developmental disparities among chicks. Hatching spread is generally assumed to be mainly determined by the onset of incubation in relation to egg laying. However, the extent to which factors other than incubation onset, such as development rate, also influence timing of hatching has received little empirical investigation. We compared incubation periods of male and female black guillemot (Cepphus grylle) embryos to ascertain whether the time taken for an egg to hatch varies with embryo sex. Laying date and egg mass had no significant effect on incubation time, but male embryos hatched on average a day sooner than did females. The onset of incubation and hatching spread vary in black guillemots. However, in mixed-sexed clutches in which the first-laid embryo is male, a faster development time of males should mean asynchronous hatching regardless of parental incubation regime. This was supported by empirical investigation. These results demonstrate that factors other than incubation behavior can be important in establishing avian hatching patterns. Whether these sex differences in development rate are a result of constraints on the degree of parental control, or an adaptive strategy to manipulate hatching patterns, remains to be established. Key words: black guillemot, embryo sex, hatching asynchrony, incubation. [Behav Ecol 15:205–209 (2004)]
TL;DR: It is revealed that beyond HH 41–42, 35°C embryos experience retarded hematological development, and the findings that support the observed delayed metabolic response to acute temperature changes are revealed.
Abstract: Hypothermic incubation reduces the ability of the late-stage chicken embryo to mount endothermic heat production. This study investigates whether blood O(2) transport is similarly limited by cooler incubation temperatures. Two populations of chicken embryos were incubated at 38 degrees C and 35 degrees C. At Hamilton-Hamburger (HH) developmental stage 41-42, hypothermic incubation had no significant effect on hematocrit ( approximately 26%) or [Hb] (7 g%). However, in the final stages of incubation (stage 43-44), hypothermic incubation reduced hematocrit from approximately 31% at 38 degrees C to approximately 27.5% at 35 degrees C. Hypothermic incubation similarly caused a reduced [Hb] from 8.5 g% (38 degrees C) to 6.25 g% (35 degrees C), indicating a reduction in blood O(2)-carrying capacity in embryos. Incubation temperature had a strong effect on blood-O(2) affinity in late development (stage 43-44), with P(50) at 38 degrees C falling significantly from approximately 6 kPa in 38 degrees C embryos to approximately 4 kPa in 35 degrees C embryos. P(O(2)) values in chorioallantoic arterial blood at HH 41-42 were 4.3 kPa at pH 7.46 (38 degrees C) and 3.4 kPa at pH 7.39 (35 degrees C). In chorioallantoic venous blood these values were 9.1 kPa at pH 7.34 (38 degrees C) and 8.1 kPa at pH 7.42 (35 degrees C). With further development to HH 43-44, chorioallantoic arterial blood oxygenation fell to 2.4 kPa at pH 7.54 (38 degrees C) and 2.8 kPa at pH 7.52 (35 degrees C). Similarly, P(O(2)) in chorioallantoic venous blood fell slightly to 7.7 kPa at pH 7.42 (38 degrees C) and 7.4 kPa at pH 7.48 (35 degrees C). Collectively, these data reveal that beyond HH 41-42, 35 degrees C embryos experience retarded hematological development, and the findings that support the observed delayed metabolic response to acute temperature changes.
TL;DR: The release of FA from islets is a novel finding and may be related to modulation of B-cell function and in comparison to unsaturated FA, being palmitic and stearic acIds the most important.