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At least 253 records · Page 14Linked to original sources
PubMed2005

Rhythms of glycerophospholipid synthesis in retinal inner nuclear layer cells.

The present study demonstrates that the biosynthesis of phospholipids in the inner nuclear layer cells of the chicken retina displays daily rhythms under constant illumination conditions. The vertebrate retina contains circadian oscillators and photoreceptors (PRCs) that temporally regulate its own physiology and synchronize the whole organism to the daily environmental changes. We have previously reported that chicken photoreceptors and retinal ganglion cells (RGCs) present significant daily variations in their phospholipid biosynthesis under constant illumination conditions. Herein, we demonstrate that cell preparations highly enriched in inner nuclear layer cells also exhibit a circadian-regulated phospholipid labeling after the in vivo administration of [(32)P]phosphate or [(3)H]glycerol both in animals maintained under constant darkness or light for at least 48h. In constant darkness, there was a significant incorporation of both precursors into phospholipids with the highest levels of labeling around midday and dusk. In constant light, the labeling of (32)P-phospholipids was also significantly higher during the day and early night whereas the incorporation of [(3)H]glycerol into phospholipids, that indicates de novo biosynthesis, was greater during the day but probably reflecting a higher precursor availability at those phases. We also measured the in vitro activity of phosphatidate phosphohydrolase and diacylglycerol lipase in preparations obtained from the dark condition. The two enzymes exhibited the highest activity levels late in the day. When we assessed the in vitro incorporation of [(14)C]oleate into different lysophospholipids from samples collected at different phases in constant darkness, reaction catalyzed by lysophospholipid acyltransferases II, labeling showed a complex pattern of daily activity. Taken together, these results demonstrate that the biosynthesis of phospholipids in cells of the chicken retinal inner nuclear layer exhibits a daily rhythmicity under constant illumination conditions, which is controlled by a circadian clock.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1977

[Submicroscopic analysis of the microcirculatory system of the pancreas in several vertebrates].

The metabolic link of the microcirculatory system of the exocrinous part of the pancreas studied electron microscopically in the frog, chicken and rat has a general plan of the structure. It consists of capillaries, pericapillary gap and intercellular clefts of glandular cells connected with it. But in the frog and chicken the adventitional layer was found to be absent from the blood capillary wall, the luminal surface of endothelial cells was increased. The width of the basal layer and intercellular clefts in the rat was less than in other objects. The existence of cytoplasmic spiculae of exocrinous pancreocytes in the pancreas of different vertebrates allows to consider them as an element of the exocrinous part microcirculatory system.

Animals↗
PubMed1986

Epidermal permeability barrier: transformation of lamellar granule-disks into intercellular sheets by a membrane-fusion process, a freeze-fracture study.

Freeze-fracture replication of lamellar granules and intercellular sheets of the horny layer in mouse, chicken, and snake epidermis reveals a pattern of serial fracture faces which is highly suggestive of polar lipids in a bilayer configuration. The occurrence of alternating wide and narrow fracture faces separated by intervening steps supports the view that epidermal barrier bilayers display lipid asymmetry similar to membranes. Within the lamellar granules, bilayers arrange to form disks which in fact are equivalent to flattened unilamellar liposomes. Stacking of the disks in turn gives rise to the lamellar pattern. After exocytosis into the intercellular space, the disks are arranged parallel to the cell membranes. In tangentially fractured specimens, the cleavage plane jumps back and forth from the plasma membrane to a disk-bilayer, thereby giving rise to the known phenomenon of EF-ridges (on the extracellular fracture face) and PF-grooves (in the plasmatic fracture face) which both represent the level of the plasma membrane sur- or subjacent to the aisles between disks. Concomitantly with the upward movement of the keratinocytes, the ridges and grooves become narrower until they fade away by the second or third cell layer of the stratum corneum. This phenomenon is explained by the fusion of adjacent disks at their highly curved brims due to a mechanism similar to the process of membrane fusion which causes the formation of wide, uninterrupted sheets.

Animals↗
PubMedDate not supplied

Pathology of listerial encephalitis in chickens in Japan.

Neural signs (torticollis, drowsiness) and mortality were observed in five chickens of a native chicken flock (reared for meat) that included 450 male birds on a farm that had 2300 native chickens and 1120 layers. Histologic lesions were observed in the medulla oblongata, optic lobe, cerebellum, and spinal cord of the affected birds. The lesions, which were most severe in the medulla oblongata, were massive abscesses with rarefaction (demyelination and malacia) of the parenchyma with gram-positive bacteria. The degenerative and necrotic areas were characterized by fibrin thrombosis, hemorrhages, and congestion in the blood vessels. Immunohistochemically, the bacteria positive for L. monocytogenes antigen were observed in the medulla oblongata, cerebellum, and spinal cord. Ultrastructurally, the small rod-shaped and thin-cell-walled bacteria were observed in the parenchyma of the medulla oblongata. Listeria monocytogenes (serotype 4b) was isolated from the medulla oblongata and spinal cord. The pathogenesis of listerial encephalitis in chickens was discussed.

Animals↗
PubMedDate not supplied

Identification of quantitative trait loci associated with bone traits and body weight in an F2 resource population of chickens.

Bone fractures at the end of lay are a significant problem in egg-laying strains of hens. The objective of the current study was to identify quantitative trait loci (QTL) associated with bone mineralization and strength in a chicken resource population. Layer (White Leghorn hens) and broiler (Cobb-Cobb roosters) lines were crossed to generate an F2 population of 508 hens over seven hatches, and 26 traits related to bone integrity, including bone mineral density (BMD) and content (BMC), were measured. Genotypes of 120 microsatellite markers on 28 autosomal groups were determined, and interval mapping was conducted to identify QTL regions. Twenty-three tests representing three chromosomal regions (chromosomes 4, 10 and 27) contained significant QTL that surpassed the 5% genome-wise threshold, and 47 tests representing 15 chromosomes identified suggestive QTL that surpassed the 5% chromosome-wise threshold. Although no significant QTL influencing BMD and BMC were detected after adjusting for variation in body weight and egg production, multiple suggestive QTL were found. These results support previous experiments demonstrating an important genetic regulation of bone strength in chickens, but suggest the regulation may be due to the effects of multiple genes that each account for relatively small amounts of variation in bone strength.

Animals↗
PubMed1994

The interaction of avian spermatozoa with the perivitelline layer in vitro and in vivo.

The differences in the hydrolytic activity of chicken spermatozoa towards the inner perivitelline layer in situ and when isolated from the ovum were investigated. Points of hydrolysis produced by chicken spermatozoa on the inner perivitelline layer of laid and freshly ovulated eggs were viewed as dark holes after staining with fluorescein-conjugated wheat-germ agglutinin. In laid eggs that had been fertilized in vivo, these holes appeared more frequently on the perivitelline layer overlying the blastodisc at the animal pole than on that overlying the vegetal pole. However, in an assay in which fragments of the inner perivitelline layer from freshly ovulated eggs were incubated with spermatozoa in vitro, points of hydrolysis appeared with similar frequency on the perivitelline layer from over the germinal disc at the animal pole or from that over the vegetal pole. No difference could be demonstrated in the electrophoretic profile of peptides extracted from the inner perivitelline layer at the animal or vegetal pole. The factor(s) responsible for either increased attraction of spermatozoa to, or for increased activity at, the perivitelline layer of the animal pole does not appear to be associated with the perivitelline layer itself.

Animals↗
PubMed2005

Exogenous leptin advances puberty in domestic hen.

The present study was undertaken to examine the effect of recombinant chicken leptin administered to fed ad libitum and feed-restricted immature chickens of a layer strain on ovarian development and the timing of sexual maturity. In the first experiment 11-week-old pullets (77 days of age) fed ad libitum were injected daily with leptin at four dose levels (4, 16, 64 and 256 microg/kg body weight) until sexual maturity (lay of the first egg). Leptin treatment at the highest dose significantly (P<0.05) advanced the onset of puberty (day 116.3+/-1.0) in comparison to controls (day 121.3+/-1.2). The rises of luteinizing hormone, estradiol and progesterone in blood plasma were also advanced by leptin treatment. In the second experiment, both full-fed and feed-restricted pullets (79 days of age) were injected daily with leptin (256 microg/kg body weight). In birds fed ad libitum, exogenous leptin again significantly (P<0.05) advanced first ovipostion (day 118.4+/-1.4 versus day 124.4+/-1.7), while abolishing the significant (P<0.05) delay caused by feed restriction (day 131.5+/-1.6) and restoring the normal onset of sexual maturity (day 125.7+/-1.6). Analysis of the ovaries in 106-day-old pullets revealed that leptin injections advanced follicular development, particularly in birds fed ad libitum, and significantly (P<0.01) reduced follicular apoptosis both in full-fed and feed-restricted birds. In conclusion, we have shown that in female chickens exogenous leptin advances the onset of puberty by attenuation of ovarian apoptosis and enhancement of folliculogenesis.

Animals↗
PubMed2006

Identification of quantitative trait loci associated with egg quality, egg production, and body weight in an F2 resource population of chickens.

Egg production and egg quality are complex sex-limited traits that may benefit from the implementation of marker-assisted selection. The primary objective of the current study was to identify quantitative trait loci (QTL) associated with egg traits, egg production, and body weight in a chicken resource population. Layer (White Leghorn hens) and broiler (Cobb-Cobb roosters) lines were crossed to generate an F2 population of 508 hens over seven hatches. Phenotypes for 29 traits (weekly body weight from hatch to 6 weeks, egg traits including egg, albumen, yolk, and shell weight, shell thickness, shell puncture score, percentage of shell, and egg shell colour at 35 and 55 weeks of age, as well as egg production between 16 and 55 weeks of age) were measured in hens of the resource population. Genotypes of 120 microsatellite markers on 28 autosomal groups were determined, and interval mapping was conducted to identify putative QTL. Eleven QTL tests representing two regions on chromosomes 2 and 4 surpassed the 5% genome-wise significance threshold. These QTL influenced egg colour, egg and albumen weight, percent shell, body weight, and egg production. The chromosome 4 QTL region is consistent with multiple QTL studies that define chromosome 4 as a critical region significantly associated with a variety of traits across multiple resource populations. An additional 64 QTL tests surpassed the 5% chromosome-wise significance threshold.

Animals↗
PubMed1995

Endogenous proteolytic enzymes in chicken muscles. Differences among strains with different growth rates and protein efficiencies.

The theory that net muscle growth is, at least partly, regulated by catabolic factors has been tested in order to set up an animal model to study meat aging and post-mortem tenderization. Male and female chickens of a layer strain (White Leghorn), a commercial broiler strain (Ross), and two experimental broiler lines (designated GL and FC) were used to estimate differences in proteolytic enzyme activities in the breast muscles. The GL and the FC lines were selected for high body weight gain and high feed efficiency, respectively. At 6 wk of age the birds were slaughtered and the activities of endogenous proteinases and their specific inhibitors in breast muscles measured. The Leghorns showed significant differences in all traits compared with the three broiler genotypes. Within the broiler types, FC birds tended in the direction of the Leghorns and GL birds in the opposite direction. Ross birds were intermediate between FC and GL birds. All types and sexes differed significantly in slaughtering weight. Feed conversion ratio and protein conversion ratio were highest for Leghorns. The FC birds showed the lowest feed conversion. Ross and GL birds showed intermediate values. The Leghorns showed higher calpain activities and lower calpastatin activity than the three broiler genotypes. The FC broilers showed intermediate calpain and calpastatin activities but higher cathepsin H and total cystatin values. The GL broilers showed lower cathepsin B, D, and H activities. In all cases the Ross broilers showed intermediate values. From these figures it is concluded that the strains of birds used in this study can be used as a natural source of variability to study the mechanisms involved in post-mortem proteolytic degradation and thus in the study of muscle tenderization and meat aging. It is also concluded that it could be very interesting to study the behavior of the different proteolytic systems more carefully in relation to muscular growth characteristics and compare them to anabolic factors involved in muscle growth.

Animals↗
PubMed1985

Chicken erythrocyte chromatin and nuclear envelope antigens.

Chromatin and inner layer nuclear envelope were isolated from chicken erythrocyte nuclei. Two antisera against dehistonized chromatin and nuclear envelope of chicken erythrocytes were obtained. Using the antiserum against dehistonized chromatin of erythrocytes we found: the presence of the antigens at approximate mol. wts of 56,000 and 77,000 tightly bound with DNA and characteristic of only erythrocyte chromatin; localized antigens at approximate mol. wts of 63,000, 68,000 and 92,000 tightly bound with DNA and common only for chromatin and nuclear envelope of chicken erythrocytes; heterogeneity of the antigens tightly bound with DNA. Using the antiserum against inner layer nuclear envelope we did not find antigens specific only for nuclear envelope and absent in erythrocyte chromatin. Some of the antigens were present in the control preparations of chicken liver chromatin and may be regarded as being species specific.

Animals↗
PubMed1999

A comparative evaluation of various invasion assays testing colon carcinoma cell lines.

Various colon carcinoma cell lines were tested in different invasion assays, i.e. invasion into Matrigel, into confluent fibroblast layers and into chicken heart tissue. Furthermore, invasive capacity and metastatic potential were determined in nude mice. The colon carcinoma cells used were the human cell lines Caco-2, SW-480, SW-620 and HT-29, and the murine lines Colon-26 and -38. None of the human colon carcinoma cells migrated through porous membranes coated with Matrigel; of the murine lines, only Colon-26 did. When incubated in a mixture of Matrigel and culture medium non-invading cells formed spheroid cultures, whereas invading cells showed a stellate outgrowth. Only the heterogeneously shaped (epithelioid and stellate) cells of SW-480 and SW-620 and the spindle-shaped cells of Colon-26 invaded clearly confluent skin and colon fibroblasts as well as chicken heart tissue. However, when transplanted into the caecum of nude and syngeneic mice, all the lines tested were invasive with the exception of Caco-2 cells. We conclude that the outcome of in vitro tests measuring the invasive capacity of neoplastic cells is largely dependent on the test system used. Invasive capacity in vitro is strongly correlated with cells having a spindle cell shape, vimentin expression and E-cadherin down regulation. In contrast, HT-29 and Colon-38 cells having an epithelioid phenotype were clearly invasive and metastatic in vivo, but not in vitro.

Animals↗
PubMed1996

A survey of the presence of a new infectious bronchitis virus designated 4/91 (793B).

On the basis of virus isolation and the demonstration of specific neutralising antibody in sera, infectious bronchitis virus (IBV) 4/91 (commonly called 793B) has been shown to be present in broiler, breeder and layer flocks of chickens in many parts of western Europe and also in Thailand and Mexico. These flocks had all been vaccinated against infectious bronchitis and the need for improved methods to control this new virus, still prevalent at least four years after it was first isolated, is discussed.

Animals↗
PubMed1987

The formation of the area centralis of the retinal ganglion cell layer in the chick.

In adult domestic chickens, the neurones in the retinal ganglion cell layer are very unevenly disposed such that there is a sixfold increase in neurone density from the retinal edge to the retinal centre. The formation of the high ganglion-cell-density area centralis was studied on chick retinal wholemounts from the 8th day of incubation (E8) to 4 weeks after hatching (4WAH). The density of viable neurones and the number and the distribution of pyknotic neurones in the ganglion cell layer were estimated across the whole retina. Between E8 and E10, the distribution of neurones in the ganglion cell layer was anisodensitic with 53,000 mm-2 in the centre compared to 34,000 mm-2 in the periphery of the retina. Thereafter, a progressively steeper gradient of neurone density developed, which decreased from 24,000 mm-2 in the retinal centre to 6000 mm-2 at the retinal periphery by 4WAH. Neuronal pyknosis in the ganglion cell layer was observed between E9 and E17. From E11 onwards, consistently more pyknotic neurones were found in the peripheral than in the central retina. It was estimated that over the period of cell death approximately twice as many neurones died per unit area in the retinal periphery than in the centre. Retinal area measurements and estimation of neurone densities in the ganglion cell layer after the period of neurone generation and neurone death indicated differential retinal expansion, with more expansion in the peripheral than in the central retina. These observations allow us to conclude that the formation of the area centralis of the chick retina involves (1) slightly higher cell generation in the retinal centre, (2) higher rate of cell loss in the retinal periphery and (3) differential retinal expansion.

Animals↗
PubMed1975

A skim milk stabilized water vaccine for Newcastle disease (B1-type LaSota): its effectiveness under modern commercial cage layer methods of delivery.

For flock vaccination, B1-type LaSota Newcastle disease water vaccine was used in chicken under commercial cage layer conditions using two different methods, Swish Corporation pipes and cups, and stainless stell troughs, in an effort to determine their effectiveness. The concentration of virus in trough and cup samples collected at the beginning and the end of the lines were the same except in one instance where little or no virus was transported to the end of the trough. Satisfactory results were obtained when the test was repeated a year later. Serum HI titers determined before and after vaccination demonstrated adequate flock serum titers and indicated that both methods of application were reasonably effective. In laboratory trials, different water pipes (black, polyvinyl chloride pipe and Hart cups, green, polyvinyl chloride pipe and Swish cups, and old, rusty, galvanized pipe) normally used in cage operations were tested. Our findings indicated that dried skim milk powder (DSMP) was essential in stabilizing vaccine virus in the containers tested and that an adequate vaccine virus concentration was maintained in the three types of pipe tested when DSMP was used. Without DSMP the vaccine titers were adversely affected.

Administration, Oral↗
PubMed2002

[Single nucleotide polymorphism analysis of the chicken Myostatin gene in different chicken lines].

Myostatin is a new member of the TGF-beta superfamily. It is specifically expressed in skeletal muscle cells and functions as a negative regulator of skeletal muscle growth. This study was aimed to identify the single nucleotide polymorphisms (SNPs) of Myostatin gene in various breeds including Beijing Youji, Baierji, Shiqiza, Dwarf Yellow Chickens, Mini Yellow Chickens, Huiyang Huxuji, Recessive White Chickens, AA and Hyline Layer. The 17 pairs of primers for Myostatin gene were designed based on the chicken genomic sequence. The total 5 SNPs were identified in the chicken Myostatin gene by PCR-SSCP of which 3 were in the 5'-regulatory region and 2 were in the 3'-regulatory region of the Myostatin gene in different chicken lines. The sequence data showed that one of the three SNPs localized in the 5'-regulatory region was due to 3 single point mutations (G304A, A322G, C334T, respectively), other two were single point mutation of G167A and T177C, respectively. The other two SNPs in the 3'-regulatory region of the Myostatin gene are A to T (7263) and A to G (6935). Population genetic analysis indicated that genotype frequencies of the Myostatin locus (P60/P61) in Beijing youji were quite different from those of other tested chicken lines. Frequency of the BB genotype was very high (0.70) while the AA genotype was only 0.033 in 5'-regulatory region (P60/P61) in Beijing youji population. The genotype frequencies (P93/P94) were significantly different among the lines (P < 0.01): frequencies of the EE genotype in Beijing Youji were lower than those in the other lines, while frequencies of the EE genotype in Baierji and Hyline Layer were higher than the rest. Frequency of allele C (P80/P81) in 9 breeds was higher than that of allele D. Frequency of genotype MM (P76/P77) was low, and that of MN was high in 7 breeds.

Animals↗