First Day Of Incubation Research Articles

Monitoring embryo development in chicken eggs using acoustic resonance analysis.

Early embryonic development was monitored using acoustic resonance frequency analysis. Based on the course of the resonance frequency (RF) of a chicken egg during incubation, detection of viable and infertile eggs or eggs in which the embryo died during the first days of incubation was possible at the beginning of day 5. A sudden decrease of the RF of viable eggs was noticed after 96-104 h of incubation, whereas infertile eggs or eggs in which the embryo died during the first days of incubation showed a smooth, continuous increase of RF during the entire period of observation. Furthermore, the interruption of the embryonic development by cold storage after 24 or 84 h of incubation delayed the moment of decreasing RF. This proves that the sudden decrease of RF corresponds to a certain stage of development. This application of acoustic resonance frequency analysis offers the potential of early, automatic detection of inviable embryo's in eggs during incubation.

Lipid peroxidation in relation to senescence of maize leaves

Summary Lipid peroxidation in relation to senescence of detached maize leaves in darkness was investigated. There was no change in malondialdehyde (MDA) level in water-treated detached maize leaves during the first day of incubation. Thereafter, there was a significant increase in the level of MDA (lipid peroxidation). Lipid peroxidation seems to be involved in the regulation of the senescence of detached maize leaves. This conclusion was based on the observations that (a) the increase in the level of lipid peroxidation preceded senescence, (b) benzyladenine, which retarded senescence, reduced the increase in lipid peroxidation level, (c) abscisic acid (ABA), methyl jasmonate (MJ) and linolenic acid, which were found to promote senescence, increase the level of lipid peroxidation, and (d) silver thiosulfate, which effectively inhibited MJ-, linolenic acid- and ABA-promoted senescence, reduced MJ-, linolenoc acid- and ABA-in-creased lipid peroxidation level.

Effects of metolachlor on activities of enzymes in a malaysian soil

Effects of metolachlor on the activities of cellulase, phosphatase, urease and protease in a loamy sand soil, were evaluated for up to 28 days. Metolachlor at 10 ppm and above caused a reduction in phosphatase and urease activities for the entire period of study. The cellulase activity decreased during the very first day of incubation compared to that of the control but a recovery trend was obvious at all concentrations from day 14 onwards. Protease activity was also reduced in the metolachlor treated soil and the lower activity was observed during the entire study.

Effects of metsulfuron-methyl on microbial biomass and populations in soils

Effects of the herbicide metsulfuron-methyl on soil microorganisms and their activities in two soils were evaluated under laboratory conditions. Measurements included their populations, soil respiration, and microbial biomass. In the clay soil, bacterial populations decreased with increasing concentration of metsulfuron-methyl during the first 9 days of incubation but exceeded that of the control soil from day 27 onward. In the sandy loam soil, the herbicide reduced bacterial populations during the first 3 days after application, but these increased to the level of untreated controls after 9 days' incubation. Fungal populations in both soils increased with increasing metsulfuron-methyl concentrations, especially in the sandy loam soil. CO 2 evolution was stimulated in both soils in the presence of the herbicide initially, but decreased during days 3 to 9 of the incubation period before increasing again afterward. The presence of metsulfuron-methyl in the soil increased microbial biomass, except in sandy loam soil at the first day of incubation.

Teratogenic and lethal effects of long-term hyperthermia and hypothermia in the chick embryo

The teratogenic effect of maternal hyperthermia is well known in laboratory animals and is presumed to exist also in humans. The aim of our study was to describe the embryotoxic effect of long-term higher and lower incubation temperatures on the chick embryo. Chick embryos were incubated within days 1 to 9 at 12 different incubation temperatures ranging from 31 to 42 °C. On the basis of our results, we estimated that there are three upper and lower critical thresholds of the incubation temperature: the first thresholds are 31 and 42 °C, at which all embryos died; the second thresholds are 32 and 41 °C, at which all living embryos were malformed; the third thresholds are 33 and 40 °C, at which some of the living embryos were without structural malformations, but their weight was shifted down and up with lower and higher temperature, respectively. The incubation temperature of 37 to 38 °C was optimal. Typical malformations detected on day 9 of incubation were microphthalmia, gastroschisis, caudal regression syndrome, and hyperlordosis, all of which occurred in dead embryos several times more frequently than in living embryos. CNS malformations were only sporadically present on day 9, as most of specimens bearing CNS defects died during the first days of incubation.

Soil pH increase due to biological decarboxylation of organic anions

Organic matter incorporated into soils may influence soil pH. Until now the detailed processes responsible for a change in soil pH after the incorporation of organic matter were not completely understood. We studied the effects of organic anions, glycine as a representative of amino acids, and glucose as a representative of carbohydrates on soil pH in aerobic incubation experiments. Addition of malate and citrate resulted in an immediate soil pH increase associated with additional CO 2 release. Addition of acetate had no major effect on soil pH but if applied at higher rates decreased soil CO 2 release. Malate added together with ammonium resulted in an immediate soil pH increase, which was followed by a pH decrease associated by an increase in nitrate after 10 days. Also glycine gave an immediate pH increase which was associated with an equivalent decrease of soil organic N extractable with CaCl 2 solution. Addition of glucose gave a slight pH decrease in the first days of incubation followed by an increase to the initial pH value. The results are interpreted in terms of decarboxylation of organic anions, a process which requires one proton per carboxylic group decarboxylated. Under aerobic soil conditions decarboxylation is a major process in organic matter decomposition. The decomposition of carbohydrates in the glycolytic pathway produces carboxylic groups which, after dissociation, may decrease soil pH. As soon as these groups are decarboxylated in the citrate cycle an equivalent amount of protons is required inducing a rise in soil pH. For this reason addition of glucose brought about only a transient soil pH decrease.

Effect of beta-carotene on cell cycle progression of human fibroblasts.

The uptake of beta-carotene (BC) and its effect on the cell cycle progression of normal human fibroblasts in primary culture were investigated by using two different delivery methods: exposure to BC solubilized in the organic solvent tetrahydrofuran (THF) or to BC incorporated into dipalmitoylphosphatidylcholine (DPPC) liposomes. Cell cycle progression was evaluated by immunofluorescence detection and flow cytometric analysis of the proliferating cell nuclear antigen (PCNA). In contrast to THF, which induced a marked reduction in the number of cells in S phase and in the extent of PCNA immunolabeling, DPPC liposomes proved to be an effective delivery system that does not interfere with cell proliferation. Cellular uptake of 0.23 nmol/10(6) cells was found after 24 h incubation in BC-containing DPPC liposomes. This value increased to 1.2 nmol/10(6) cells after 72 h. After the first day of incubation, the number of cells in S phase was reduced by approximately 50%, with a consequent accumulation of cells in G1 phase. This effect was maintained up to 3 days incubation, with no detectable effects on cell viability. This cell cycle delay was found to be reversible, returning the percentage of cells in S phase to the control value 24 h after removal of BC from the medium. In order to determine whether the activity of BC could be attributed to the molecule itself or to its conversion into retinoids, the production of BC metabolites was assessed. Analysis of cellular levels of retinoids failed to demonstrate the presence of retinal, retinol, retinoic acid or retinyl esters during an incubation period of 6 days. These results suggest that in normal human fibroblasts, BC induces a cell cycle delay in the G1 phase and that this effect is independent of conversion to known retinoids.

Embryonic development of the domestic guinea fowl (Numida meleagris)

Inside the viable range 36–39°C, the development of the domestic guinea fowl embryo was studied during artificial incubation of about 5000 eggs. Equations giving internal and external pipping and hatching time as a function of incubation temperature were developed. Whatever temperature was used, internal and external pipping occurred at 89% and 95% of hatching time, respectively. The chronological development in ovo of the guinea fowl is illustrated by growth curves. Guinea fowl grew in ovo at the same rate as the chicken embryo. The embryonic mortality is significantly affected by incubation temperature. The thermal tolerance of the embryo follows a parabolic curve: temperatures below or above 37.2°C increase the rate of mortality. During the course of the incubation, the mortality frequency was mainly distributed around two peaks (each one third of the total), which occurred during the first days of incubation, that is, within the first 12% of the incubation time, and during the last days, that is, after 85% of the incubation time. At the optimal 37.2°C temperature, these two peaks occurred on days 1–3 and 23–27, respectively.

Oxidative Defense Systems in Leaves of Three Edible Herb Species in Relation to Their Senescence Rates

Correlation studies between leaf senescence rates of three edible herb species, watercress (Rorippa nasturtium-aquaticum), parsley (Petroselinum crispum), and sage (Salvia officinalis L.), and their oxidative defense systems were conducted with detached leaves under simulated shelf-life storage conditions. The relative order of leaf senescence rate, based on their rate of chlorophyll (Chl) degradation and malondialdehyde accumulation, was watercress>parsley>sage. However, all three herb species showed high proteolysis rates from the first day of incubation. Of five oxidative defense systems examined in the three herb species, only the system of total reducing capacity correlated well with their relative order of Chl degradation and could therefore predict their storage potential

Developmental study of the long QT with deafness syndrome in the chick embryo: cochlear pathology

Developmental abnormalities of the peripheral auditory structures in an experimental animal model of the cardio-auditory (long QT with deafness) syndrome are described. Prolonged QT intervals in the electrocardiogram and deafness were induced in chick embryos by removal of tissue in the region of the right nodose and otic placodes on the first day of incubation. Electrocardiographic recordings, cochlear potential and brainstem auditory evoked responses were recorded in late embryonic life (El7), and used to identify embryos with long QTs and deafness. External and middle ears were evaluated under a dissecting microscope. Inner ears were evaluated in histological sections. Anomalies of the external and middle ears, such as the external auditory meatus, tympanic membrane and stapes, were attributed to disturbance of neural crest development. Anomalies of the inner ear, such as a complete absence of the cochlear duct and auditory nerve, or decreased length of the basilar papilla, were attributed to disturbance of otic placode development. The fact that a small lesion in the region of the nodose and otic placodes during early development in the chick animal model can produce a long QT interval in the electrocardiogram and deafness suggests that abnormal development in this region early in development might be the underlying cause of the human syndrome.

Corrigenda - Adsorption and degradation of triazine herbicides in soils used for lupin production in Western-Australia - Laboratory studies and a simulation model

Most lupins (Lupinus angustifolius L. and L. albus L.) grown in Western Australia are sown with simazine, and some with atrazine, to give persistent control of a broad spectrum of weeds. Rates of application are adjusted for soil types yet there can be ineffective weed control and crop damage. The kinetics of degradation in four soils was studied in the laboratory to determine how it varied between soils and was modified by soil temperature, pH, moisture and gamma irradiation. The time for half the herbicide to be lost from the soils (HL) varied from 42 to 110 days at 20�C and -0.08 MPa water potential. Loss was rapid in the first day of incubation and subsequent losses were described precisely by first-order functions. However, the first-order half-lives (t1/2) were 3-21 days greater than the corresponding HLs, because the first-day losses were unaccounted for by the first-order functions. Gamma irradiation had no influence on degradation kinetics which supported chemical hydrolysis as the mechanism of degradation. The t1/2 values were correlated positively with the proportion of applied herbicide that was adsorbed by the soils (PAd). Atrazine was more persistent than simazine and had higher PAd values. The PAd values increased with soil pH, organic matter and clay content. The t1/2 values decreased exponentially with temperatures from 28 to 9-degrees-C, and decreased with soil water potentials from -0.08 to -1.50 MPa for a loamy sand at a near-neutral pH. A computer simulation model gave good agreement with observed residue decays and showed that the initially rapid losses from the soils could be explained by high rates of hydrolysis when all the applied herbicide was in the soil solution and, consequently, herbicide concentrations were high (87-100 mM). Rapid losses of the triazines in the field are likely in warm, acidic soils-particularly if the herbicide concentrations in the soil solution are high for reasons of limited vertical distribution of the applied herbicides through the soil profile.

Adsorption and degradation of triazine herbicides in soils used for lupin production in Western-Australia - Laboratory studies and a simulation model

Most lupins (Lupinus angustifolius L. and L. albus L.) grown in Western Australia are sown with simazine, and some with atrazine, to give persistent control of a broad spectrum of weeds. Rates of application are adjusted for soil types yet there can be ineffective weed control and crop damage. The kinetics of degradation in four soils was studied in the laboratory to determine how it varied between soils and was modified by soil temperature, pH, moisture and gamma irradiation. The time for half the herbicide to be lost from the soils (HL) varied from 42 to 110 days at 20�C and -0.08 MPa water potential. Loss was rapid in the first day of incubation and subsequent losses were described precisely by first-order functions. However, the first-order half-lives (t1/2) were 3-21 days greater than the corresponding HLs, because the first-day losses were unaccounted for by the first-order functions. Gamma irradiation had no influence on degradation kinetics which supported chemical hydrolysis as the mechanism of degradation. The t1/2 values were correlated positively with the proportion of applied herbicide that was adsorbed by the soils (PAd). Atrazine was more persistent than simazine and had higher PAd values. The PAd values increased with soil pH, organic matter and clay content. The t1/2 values decreased exponentially with temperatures from 28 to 9-degrees-C, and decreased with soil water potentials from -0.08 to -1.50 MPa for a loamy sand at a near-neutral pH. A computer simulation model gave good agreement with observed residue decays and showed that the initially rapid losses from the soils could be explained by high rates of hydrolysis when all the applied herbicide was in the soil solution and, consequently, herbicide concentrations were high (87-100 mM). Rapid losses of the triazines in the field are likely in warm, acidic soils-particularly if the herbicide concentrations in the soil solution are high for reasons of limited vertical distribution of the applied herbicides through the soil profile.

Phospholipid loss in dying platelets.

The death of a cell results in a large amount of membrane lipid, predominantly phospholipids and cholesterol, that must be eliminated. In this study, we have examined what happens to phospholipids in dying rat platelets. Rat platelets were incubated for up to three days following their activation with thrombin. Platelet death occurred during the first day of incubation. This was indicated by a complete loss of platelet lactate dehydrogenase into the incubation medium. The platelets progressively lost over one-half of their phospholipid content during the three days of incubation. Cholesterol and sphingomyelin (the phospholipid with the highest affinity for cholesterol) were not lost during the same period. Our findings suggest that significant degradation of cellular non-sphingomyelin phospholipid can be triggered by cell death. The preservation of sphingomyelin in dying platelets, may be an adaptive response to maintain cholesterol in a solubilized state within dying cells.

Effect of Hyaluronic Acid on Rabbit Profundus Flexor Tendon Healing in Vitro

We performed an in-depth biomechanical evaluation of the effect of hyaluronic acid (HA) on the healing of rabbit profundus tendons cultured in vitro. Seventy-eight flexor tendons from 13 rabbits were transected and reapproximated at their Zone II midpoints. Tendons were divided into left and right forepaw groups. Each tendon from the left forepaw group was incubated in one of four possible culture media: control (no HA), low (0.1 mg/ml), medium (0.5 mg/ml), or high (1.0 mg/ml) HA media. HA was added on the first day of incubation. Each tendon from the right forepaw group was cultured in low, medium, or high concentrations of HA, but HA was added after 1 week of incubation in control media. All tendons were cultured for 8 weeks, after which time tenorrhaphies were disrupted and the following biomechanical parameters were determined: apparent maximum stress, apparent strain at apparent maximum stress, normalized energy absorption, and tangent modulus before failure. Comparisons using these parameters showed no statistically significant differences among the various tendon groups. We believe this is the first study of its kind to show no effect of hyaluronic acid on the functional strength of tendon after healing in vitro.

Evaluation of the pediatric Septi-Chek blood culture system

The pediatric Septi-Chek blood culture system is a biphasic system that uses a 20-ml bottle of brain-heart infusion broth. We compared this system with a supplemented peptone broth tube (Vacutainer) for the recovery of aerobic organisms from blood cultures obtained from patients in a pediatric hospital. Blood specimens for culture were drawn into transport tubes containing sodium polyanetholsulfonate (SPS), and equal volumes were allocated into a Septi-Chek bottle and a Vacutainer tube which was vented for the first day of incubation. A total of 4828 blood culture sets was included, from which 243 probable pathogens were recovered, including 211 in the Septi-Chek system and 204 from the Vacutainer tube. There were no significant differences in the recovery of individual pathogens. The mean time to initial detection of pathogens was comparable in the two systems, but the mean time to growth on solid media for pathogens recovered in both systems was shorter with Septi-Chek (37.2 hr compared with 45.5 hr, p < 0.001). The pediatric Septi-Chek system is comparable with a vented Vacutainer tube for the recovery of aerobic pathogens, and its use facilitates the early identification and susceptibility testing of bloodstream pathogens.

Colorbact, a visually read blood culture system using darkening of haemoglobin in aerobic blood cultures as an early growth indicator, compared with Bactec® 6A and 7A

Colorbact-A (aerobic), a blood culture system using darkening due to oxygen reduction and acidification of haemoglobin as an initial growth indicator during the first day of incubation of continuously agitated, aerobic blood cultures, was compared with the 24 h agitated aerobic Bactec 6A in 1767 consecutive paired cultures. Both systems were examined simultaneously twice daily during the first two days and once daily the next five days of incubation. In addition, during the agitation period Colorbact-A was observed for darkening four to five times during day duty between 8 a.m. and 4 p.m. The final seven days detection rate found by Colorbact-A using observation for darkening during initial agitation was similar to the rate found by Bactec 6A for both clinically significant strains and "contaminants", but Colorbact-A was significantly faster (p less than 0.001) in finding clinically significant strains. Colorbact-AN (anaerobic) was more rapid (p less than 0.01) and yielded more positive cultures than the anaerobic Bactec 7A. The Colorbact system was flexible, inexpensive, reliable and especially promising for laboratories which receive blood cultures from other hospitals once daily, as many positive cultures can be found immediately on arrival undisturbed by agitation during transport.

Turnover of carbon through the microbial biomass in soils with different texture

Ten soils, with the same type of clay and under the same management but having different clay contents, were amended with 14C-labelled glucose and incubated for 90 days to determine the influence of texture on the turnover of C through the microbial biomass. After 90 days, there was little difference among the soils in residual 14C. However, rates of CO 2 evolution and mineralization indicated that during the first day of incubation, the rate of decomposition of substrate C was greater in soils with more clay. From 1 to 5 days the turnover of C through the biomass was relatively slower in these soils. Total biomass C (labelled + unlabelled C) contents reached maximal amounts after 1.25 days and were maintained at higher quantities in soils with greater amounts of clay until the end of the incubation. Biomass 14C was maintained at higher amounts in soils with more clay but only until 45 days. The proportion of C derived from the labelled glucose and incorporated in the biomass ranged from 59 to 73% after 1.25 days and from 16 to 20% after 90 days. The unlabelled biomass was significantly correlated with the amount of clay at all sampling dates and appeared to be qualitatively different than the labelled biomass in the heavy tcxturcd soils. After 1.25 days of incubation, the non-living 14C accounted for 12 to 23% of added to glucose 14C; after 90 days it ranged from 11 to 20%. The ratio of living to non-living 14C was consistently higher in soils with more clay. This was attributed to adsorption of non-living C by clay and to product utilization by a secondary population.

Endogenous Cytokinins in Flower Bud Forming Explants of Tobacco

The accumulation of endogenous cytokinins was studied in pedicel expiants of tobacco (Nicotiana tabacum L.) during regeneration of flower buds in vitro. Maximal bud formation was induced on media containing 1-Ommol m 3 of benzyladenine or dihydrozeatin. No buds were formed in the absence of cytokinin. The levels of dihydrozeatin, zeatin, and the corresponding ribosides were determined in expiants cultured in the presence or absence of cytokinin by means of a competitive ELISA technique. In expiants incubated without a cytokinin, only the dihydrozeatin concentration increased significantly during the first day of incubation and decreased during the second day. No increase was observed in expiants incubated in the presence of benzyladenine. The concentration of dihydrozeatin in these bud-forming expiants was only 10 to 15% of the concentration built up in expiants cultured on dihydrozeatin instead of benzyladenine. This suggests that the endogenous cytokinins only play a minor role in the regeneration of flower buds in vitro.

Volume-selective and spectroscopically resolved NMR investigation of diffusion and relaxation in fertilised hen eggs

A radiofrequency and field-gradient pulse sequence is presented permitting the non-invasive, volume-selective and spectroscopically resolved determination of incoherent transport parameters with the aid of an NMR field-gradient method. With proton NMR, diffusion or (quasi-incoherent) perfusion coefficients as low as 10-12 m2 s-1 are accessible with gradients G100 mT m-1 for T20.3 s. If coherent motions like flow are superimposed, the gradient pulses can be compensated for phase shifts arising from uniform or accelerated motions. The efficiency of the suppression of the influence of coherent motions was demonstrated in test experiments with phantom sample arrangements. As a biophysical application, the local diffusion coefficients D and relaxation times T1 and T2 of hen eggs were studied during the first days of incubation. In the yolk, strongly non-exponential decay curves were observed for the CH2 line. The translational displacements of water were found to be restricted. The relaxation and diffusion parameters turned out to be constant during the incubation.

Biochemical mechanisms of aminoglycoside cell toxicity. II. Accumulation of phospholipids during myeloid body formation and histological studies on myeloid bodies using twelve aminoglycoside antibiotics.

Cultured human skin fibroblasts take up aminoglycoside antibiotics into lysosomes to form myeloid bodies. Gentamicin (GM), one such antibiotic, was taken up until the cellular concentration reached an estimated 64 mM on the 3rd day when cells were incubated with 2 mM gentamicin. The rate of release of intracellular GM was high on the first day of incubation and gradually slowed down over the next 4 d. About 50% of the GM remained in the cells even on longer incubation in GM-free medium, suggesting it may irreversibly bind to cellular components. With myeloid body formation, the cellular phospholipid content increased 1.5 times. Bis(monoacyl-glyceryl)phosphate, which is known as a marker of lysosomal phospholipid, phosphatidylcholine and phosphatidylserine showed 250, 162, and 153% increases, respectively. Sphingomyelin was not accumulated, while lysosomal sphingomyelinase was dramatically inhibited. Of 12 different aminoglycoside antibiotics, paromomycin is the most prominent myeloid body-forming antibiotic. The myeloid body-formation is not directly correlated to human nephrotoxicity. On the other hand, the number of myeloid bodies is well correlated to the affinity to the brush border membrane, suggesting that such aminoglycoside antibiotics are taken up easily through cellular endocytosis. The cytotoxic effects of aminoglycoside antibiotics may be due to by their binding to cellular organelles other than lysosomes.