Chick hepatic lectins: An electron microscopic study on isolated hepatocytes during development

We studied the carbohydrate recognition systems of hepatocytes isolated from 16-day-old embryos, 19-day-old embryos and chicks within 24 h of hatching. We localized and quantified at the ultrastructural level the binding sites for glycoproteins exposing terminal N-acetylglucosamine (GlcNAc), mannose and N-acetylgalactosamine (GalNAc) residues by means of protein-gold complexes. Binding sites specific for GlcNAc and mannose residues are present on hepatocytes from embryos and chicks. On the contrary GalNAc specific binding sites are exclusively observed on cells from 16-day-old embryos. The number and distribution of gold particles on hepatocyte cell surfaces depend on the binding sites and the age considered. We describe a modulation in the number of GlcNAc, and mannose specific receptors present on the cell surface between the embryonal stage and neonatal life.     

Physiological status of broiler chicks at pulling time and the relationship to duration of holding period

Newly hatched chicks may be held longer than 48 h and experience long periods of fasting in commercial hatcheries. Limited information is known about the physiological status of chicks in such situations, due to the difficulty of precisely recording time of hatch. This study investigated the effect of the time from hatch to pulling (holding period) on physiological measures/parameters in 109 broiler chicks. Fertile Ross 308 eggs were incubated in a custom built small-scale incubator. The individual hatching time of each focal chick was determined using eggshell temperature monitoring. At ‘pulling’ (512 h of incubation time), the quality of focal chicks was assessed using the chick scoring method and physiological parameters were measured including BW, organ (heart, liver and stomach) weights, blood values and plasma corticosterone level. The time from hatch to pulling varied from 7.58 to 44.97 h. Egg weight at setting was significantly correlated with chick BW and weight of organs at pulling, but had no effect on chick quality, blood values and plasma corticosterone. Relative BW at pulling was negatively associated with the duration of holding period (P=0.002). However, there was a positive correlation between relative stomach weight and the duration of the holding period (P<0.001). As the holding period duration increased, there was a trend that blood partial pressure of oxygen, haematocrit and haemoglobin also increased, and blood partial pressure of carbon dioxide, total carbon dioxide and bicarbonate decreased (P<0.05). A wide range of plasma corticosterone was observed from chicks that had experienced different durations of holding period. We conclude that shortening the hatch window and minimising the number of chicks that experience a long holding period before pulling may improve chick quality and physiological status, which may be due to unfavourable environmental conditions that include feed and water deprivation.     

Effect of different fetal bovine serum concentrations on the replicative life span of cultured chick cells

Summary The effect of Eagle's minimal essential medium, containing different fetal bovine serum (FBS) concentrations, on the proliferation and replicative life span of cultured chick cells has been studied. Our results showed that the rate of chick cell proliferation and the cell density at stationary phase increased as a function of serum concentration between 5 and 30% FBS. The replicative life span of cultured chick cells was dependent on the FBS concentration between 5 and 20% in a medium volume of 0.20 ml/cm². The maximum replicative life span of chick cells was obtained by serially propagating cells in a medium volume of 0.20 ml/cm² containing 20 or 30% FBS, or, alternatively, in 0.53 ml/cm² containing 10, 20 or 30% FBS. Cells grown in medium containing 5% serum had a calendar life span of 35 days, whereas cells propagated in medium containing higher serum concentrations had a calendar life span of 50 days. These results reenforce the concept that, although the kinetics of cell population aging can be affected by the culture medium composition, the aging of cells in culture is controlled by alterations within the cell. This work was supported by IIT Research Institute.     

Inhibition of focal adhesion kinase expression correlates with changes in the cytoskeleton but not apoptosis in primary cultures of chick embryo cells

Cell adhesion to the extracellular matrix through integrin receptors can activate signaling cascades within the cell. Focal adhesion kinase (FAK) is a protein tyrosine kinase activated by integrin adhesion. The role of FAK within the cell is not clear, although evidence suggests roles in cell motility or the regulation of adhesion-dependent cell survival. We have treated primary cultures of chick embryo cells with antisense oligonucleotides to FAK to reduce the level of FAK protein expression. Levels of the related protein, proline-rich tyrosine kinase 2 (Pyk2) and the FAK substrate paxillin, were unaffected by the addition of oligonucleotides, whereas FAK expression was reduced by 70%. Levels of apoptotic cell death did not significantly increase after the addition of oligonucleotides. However, there was a change in the distribution of focal adhesion sites from a uniformly distributed pattern to a mainly peripheral pattern. This was accompanied by a loss of stress fibers and an increase in the peripheral actin cytoskeleton, as the cells became rounded. These results suggest that in these early embryonic cells, FAK expression regulates the arrangement of focal adhesions and the cytoskeleton that result in a motile phenotype, but that FAK does not appear to regulate apoptosis.     

Cultivation of the cercaria of Himasthla quissetensis (Trematoda) on the chick chorioallantois

Cercariae of Himasthla quissetensis were cultivated on the chick chorioallantois maintained at 38 ± 1°C and a relative humidity of 70–75%. Of 68, 6-day-old eggs, each inoculated with 100 cercariae, 28 (41%) were examined 1–9 days post-inoculation. Of the 28 eggs, 23 (82%) were infected with a total of 224 live worms plus 10 encysted metacercariae. Worms contained blood or hematin-like material in their intestinal caeca and showed considerable development of reproductive structures. A total of 58, 6- or 7-day-old chorioallantoic-worms were serially transferred to new 6-day-old embryos, but only a single live worm was recovered after 13 days on two membranes. Based on fixed and stained specimens, 7-day-old chorioallantoic-worms increased their body area about 4× compared to cercariae and the 13-day-old worm increased its body area about 10×.     

Isolation and Preliminary Characterization of Novel Polysialogangliosides from Embryonic Chick Brain

Abstract Preparative thin-layer chromatography was used to isolate from embryonic chick brains four different polysialogangliosides which moved below GT1b on TLC plates. These possessed molar sialic acid-to-sphingosine ratios of 4:1, 5:1, 6:1, and 7:1, respectively. Mild neuraminidase ( Clostridium perfringens ) treatment of the three most highly sialylated fractions gave GTlb and GDlb transiently, but the only accumulating ganglioside was GM1. All three polysialogangliosides were also found in Elasmobranch brains. During development of the chicken the concentrations of the two most slow-moving fractions ("hexa"-, and "septa"-sialogangliosides) decreased.     

Habitat selection,diet and food availability of European Golden Plover Pluvialis apricaria chicks in Swedish Lapland

Fennoscandian alpine tundra habitats support large numbers of breeding waders, but relatively little is known about their breeding ecology despite the fact that this habitat is threatened by climate change. We studied habitat selection, diet and prey availability of European (Eurasian) Golden Plover Pluvialis apricaria chicks at the Vindelfjällen Nature Reserve, Ammarnäs, Sweden. Information from 22 chicks tracked using radio‐transmitters was analysed. By analysing 149 faecal samples, four main prey taxa were identified, Coleoptera (40%), Bibionidae (31%), Hymenoptera (13%) and Tipulidae (10%). We found that chicks switched from feeding on Tipulidae to feeding on Bibionidae as they grew, and that this switch coincided with a shift from the use of the habitat where Tipulidae were abundant (alpine meadow/heathland) to the use of the habitat were Bibionidae were abundant (Willow shrub). Although chicks track food availability to some extent, the link between prey availability and habitat use was not perfect, indicating that additional factors other than food abundance, such as shelter from predators, determine habitat selection. Bibionidae are an important prey for Golden Plover chicks as it is the only prey group that has a late summer flush in abundance, in contrast to the general decline of total arthropod biomass during the chick‐rearing period. However, Bibionidae imagoes only occurred in 2011 and were virtually absent in 2013, which relates to the species’ ecology with 2‐ to 5‐year cycles in mass occurrence. Extreme annual variation in an essential food source such as Bibionidae imagoes might have an important effect on the condition and survival of Golden Plover chicks, an important subject for future studies. The foraging conditions for Golden Plover chicks in Fennoscandia appear to be different to those in the UK, where the chicks rely mainly on a Tipulidae flush only.     

Time‐lapse imaging system with shell‐less culture chamber

We have developed a system for imaging whole chick embryos from embryonic day 1.5 (E1.5) to E4.5. Our system consists of a custom‐made culture chamber, the top and bottom of which were heated and the inside was humidified. The system also has a fixed stage uplight fluorescent microscope, and long‐working distance objective lenses were adopted. The albumen removed‐yolk with the embryo in the dish was put in the chamber. It is of importance that we adopted long working distance lenses because the working distance of conventional objective lenses is too short for observation of the embryo in a humidified chamber. The objective lens we adopted has sufficient resolution to detect fluorescent protein expression at the single‐cell level. Transparent glass heater set on the top of the chamber helps to reduce dew condensation; the bottom heater keeps the temperature inside the chamber, and the water bath surrounding the egg maintains humidity. This system was used to detect fluorescent protein expressing cells in embryos. We could successfully trace those cells for 17 h in vivo. In conclusion, this system is useful for time‐lapse analysis of fluorescent protein expression and distribution for a longer period of time.     

鸡胚发育后期心电图的无损测定及心率变化

目的：测量鸣胚发育后期心电图,测定鸡胚发育后期心率及其变化.方法：利用壳膜外电极测量鸡胚心电图,根据RR间期计算鸡胚心率。结果：引出了具有较为清晰Q波、R波（振幅在8—20μV波动）、S波的鸡胚心电图。鸡胚的QRs间期在发育后期无明显变化,心率在D14～D20早期的心率变化较小,在D20后期和D21显著增加（P〈0．01）。结论：建立了壳膜外记录鸡胚心电图的方法,鸡胚在啄壳期心率显著增加.     

在鸡胚绒毛尿囊膜上评价血管生成技术的应用与优化

目的：用鸡胚绒毛尿囊膜（CAM）评价血管生成并进行优化,为抗血管生成药物筛选提供良好的体内实验模型。方法：对CAM技术的各个环节,包括合适日龄胚蛋选择、蛋壳开窗及暴露CAM的方法、载体选择、结果分析等进行了实验对比。结果：采取气室开窗,以甲基纤维素为药物载体,促进血管生成的药物在孵化11d以后、抑制血管生成的药物在孵化7～9d给药,鸡胚存活率为85.8%,生长状况良好,被检测药物有明显的抑制或促进血管生成的效应。结论：通过优化建立了操作简便、鸡胚存活率高的在CAM上评价血管生成的技术;应用CAM技术评价了若干影响血管生成的因子。     

Microwave effects on isolated chick embryo hearts

This study was designed to examine the effects of microwaves on the electric activity of hearts as a means of elucidating interactive mechanisms of nonionizing radiation with cardiac tissue. Experiments were performed on isolated hearts of 9-12-day-old chick embryos placed in small petri dishes. Oxygenated isotonic Ringer's solution at 37 degrees C permitted heart survival. Samples were irradiated at 2.45 GHz with a power density of 3 mW/cm2. The heart signal was detected with a glass micropipet inserted into the sinoatrial node and examined by means of a Berg-Fourier analyzer. Pulsed microwaves caused the locking of the heartbeat to the modulation frequency, whereas continuous wave irradiation might have induced slight bradycardia. Pulsed fields induced stimulation or regularization of the heartbeat in arrhythmia, fibrillation, or arrest of the heart.     

Method for electroporation for the early chick embryo

In vitro whole-embryo culture of chick embryos, originally invented by New, has been widely used for studies of early embryogenesis. Here, a method for electroporation using the New culture and its derivatives is described, to achieve misexpression of exogenous gene in a temporally and spatially controlled manner in gastrulating chick embryos. Detailed information for the devices and procedures, and some experimental examples are presented.     

A rapid protocol for sexing chick embryos (Gallus g. domesticus)

A method for establishing the sex of chick embryos before the appearance or morphological differences between males and females has been developed. DNA was isolated from 5–7-day-old embryos by proteinase K digestion and subjected to polymerase chain reaction (PCR) amplification with W-chromosome specific primers. Sexing can be achieved within 1 day using as little as 1 ng template DNA.     

Transmitter Effects on Growth and Survival of Forster's Tern Chicks

Radio-telemetry is a commonly used scientific technique that allows researchers to collect detailed movement, habitat use, and survival data of animals; however, evidence indicates that using telemetry can affect behavior and survival. Using multiple breeding colonies and years, we investigated the effects of attached radio-transmitters on growth and survival of Forster's tern (Sterna forsteri) chicks in San Francisco Bay, California, USA, 2010–2011. We tested these potential effects at isolated islands that allowed for high re-capture rates (typically >85%) in radio-marked and banded-only chicks. Modeled Gompertz growth curves suggested that transmitters had a small negative effect on some of the asymptotic growth parameters of tern chicks; tarsus (−1.5 ± 0.7% [SE]), culmen (−1.7 ± 1.2%), and wing (−4.9 ± 2.0%) lengths were shorter for radio-marked chicks compared to banded-only chicks. In contrast, there was no difference in asymptotic mass between radio-marked chicks and banded-only chicks. Survival from hatching to fledging was lower for radio-marked chicks than banded-only chicks during 2010 (banded-only = 0.313 ± 0.162 vs. radio-marked = 0.250 ± 0.165) and 2011 (0.193 ± 0.030 vs. 0.123 ± 0.027). Most of the transmitter effect occurred within the first week after hatching, rather than in older chicks. Notably, the effect of transmitters on chick survival was primarily additive, indicating that the effect of transmitters on radio-marked chicks was not influenced by other ecological covariates. Given the effect radio-transmitters had on survival did not change across temporal or ecological gradients, transmitters can still be used to evaluate ecological factors affecting survival and timing of mortality and radio-marked birds can be used to make inferences to the general population. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.     

Ectodermal-mesenchymal interspace during the formation of the chick leg bud

Summary The ectodermal-mesenchymal interspace of the chick leg bud was studied at stages leading to the formation of the apical ectodermal ridge (A.E.R.) (stages 14 to 19 HH), using scanning and transmission electron microscopy. The main findings were: 1. a continuous basal lamina under the ectoderm; 2. extracellular fibrils interconnecting the basal lamina and mesenchymal cell processes; 3. an increase in the number of the fibrils during these stages, with the highest number under the A.E.R.; 4. branching mesenchymal cell processes that spread over the basal lamina, making contact with it in all stages. The morphology of the interspace and the changes in it suggest that extracellular material may be significant in the ectodermal-mesenchymal interactions in the limb bud.     

Pre‐/post‐otic rhombomeric interactions control the emergence of a fetal‐like respiratory rhythm in the mouse embryo

How regional patterning of the neural tube in vertebrate embryos may influence the emergence and the function of neural networks remains elusive. We have begun to address this issue in the embryonic mouse hindbrain by studying rhythmogenic properties of different neural tube segments. We have isolated pre‐ and post‐otic hindbrain segments and spinal segments of the mouse neural tube, when they form at embryonic day (E) 9, and grafted them into the same positions in stage‐matched chick hosts. Three days after grafting, in vitro recordings of the activity in the cranial nerves exiting the grafts indicate that a high frequency (HF) rhythm (order: 10 bursts/min) is generated in post‐otic segments while more anterior pre‐otic and more posterior spinal territories generate a low frequency (LF) rhythm (order: 1 burst/min). Comparison with homo‐specific grafting of corresponding chick segments points to conservation in mouse and chick of the link between the patterning of activities and the axial origin of the hindbrain segment. This HF rhythm is reminiscent of the respiratory rhythm known to appear at E15 in mice. We also report on pre‐/post‐otic interactions. The pre‐otic rhombomere 5 prevents the emergence of the HF rhythm at E12. Although the nature of the interaction with r5 remains obscure, we propose that ontogeny of fetal‐like respiratory circuits relies on: (i) a selective developmental program enforcing HF rhythm generation, already set at E9 in post‐otic segments, and (ii) trans‐segmental interactions with pre‐otic territories that may control the time when this rhythm appears. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006     

Cultivation of excysted metacercariae of Echinostoma revolutum (Trematoda) in chick embryos

Three techniques were used to study post-metacercarial growth and development of chemically excysted metacercariae of Echinostoma revolutum on the chorioallantoic membrane of domestic chick embryos. The in ovo technique of Zwilling (1959) and the in vitro technique of Auerbach et al. (1974) provided for better worm recovery in chick embryos than the in ovo technique of Woodruff &; Goodpasture (1931). Regardless of the technique used, postmetacercarial development was obtained for this species, and 6- to 8-day-old chorioallantoic-wornis achieved sexual development to the coiled uterus stage comparable to worms grown in domestic chicks for 7 days. However, somatic growth of worms from the chorioallantois was stunted when compared to worms grown in chicks. Worms grown on the chorioallantois voided their excretory concretions and showed histochemical lipid staining identical to that seen in worms grown in chicks.     

Glutamate-like immunoreactivity in chick cerebellum and optic tectum

Glutamate was coupled via glutaraldehyde to bovine serum albumin. The conjugate was used for raising specific anti-glutamate antibodies. The purified antibody was used for immunostaining of chick cerebellum and optic tectum. Staining was intense in the molecular layer and in cell bodies of the granule cell layer. In the optic tectum a diffuse staining was detected in the superficial layers of stratum griseum fibrosum superficiale and in cell bodies especially in the layers a and e. Large cell bodies located in the stratum griseum centrale were also stained.