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Biomedical subjects

D Windsor

Publications and source records attributed to D Windsor.

At least 19 recordsLinked to original sources
PubMed2006

QTL analysis of body weight and conformation score in commercial broiler chickens using variance component and half-sib analyses.

The aim of the study was to investigate quantitative trait loci (QTL) in previously identified regions of chicken chromosomes 1, 4 and 5 relating to 40-day body weights and conformation scores. Half-sib (HS) and variance component analyses were implemented and compared using QTL Express software. Data were from a two-generation design and consisted of 100 dam families nested in 46 sire families with trait values for 2,708 offspring. Chicken chromosome 4 showed nominal significance for QTL affecting body weight and conformation, and linkage was confirmed for both traits on chromosome 5. Results varied according to method of analysis and with common parent in the HS method.

Animals↗
PubMed2005

Mycoplasma amphoriforme sp. nov., isolated from a patient with chronic bronchopneumonia.

A mycoplasma was isolated from the sputum of an immunodeficient patient with recurrent bronchitis. The isolate designated strain A39T was very fastidious and atypical for a mycoplasma in its colonial appearance. Classical biochemical tests for mycoplasma speciation could not differentiate the isolate from the pathogens Mycoplasma pneumoniae and Mycoplasma genitalium and serological identification as a recognized Mycoplasma species was lacking. Specific PCR detection for these two species was negative. Subsequently, other strains were isolated from human patients that appeared to be similar to strain A39T in their physiological and genetic characteristics. Analysis of the 16S rRNA gene placed strain A39T and other isolates in the pneumoniae group of mycoplasmas, with the highest sequence similarity to Mycoplasma testudinis (96.8 %), but with only 93.0 % similarity to M. pneumoniae and M. genitalium. Examination of the 16S-23S rRNA internally transcribed spacer sequence, protein electrophoresis profile, genome size and serological reactions indicated that this organism represents a novel species, for which the name Mycoplasma amphoriforme sp. nov. is proposed, with strain A39T (=NCTC 11740T=ATCC BAA-992T) as the type strain.

Bronchopneumonia↗
PubMed2004

Segregation of QTL for production traits in commercial meat-type chickens.

This study investigated whether quantitative trait loci (QTL) identified in experimental crosses of chickens provide a short cut to the identification of QTL in commercial populations. A commercial population of broilers was targeted for chromosomal regions in which QTL for traits associated with meat production have previously been detected in extreme crosses. A three-generation design, consisting of 15 grandsires, 608 half-sib hens and over 15 000 third-generation offspring, was implemented within the existing breeding scheme of a broiler breeding company. The first two generations were typed for 52 microsatellite markers spanning regions of nine chicken chromosomes and covering a total of 730 cM, approximately one-fifth of the chicken genome. Using half-sib analyses with a multiple QTL model, linkage was studied between these regions and 17 growth and carcass traits. Out of 153 trait x region comparisons, 53 QTL exceeded the threshold for genome-wide significance while an additional 23 QTL were significant at the nominal 1% level. Many of the QTL affect the carcass proportions and feed intake, for which there are few published studies. Given intensive selection for efficient growth in broilers for more than 50 generations it is surprising that many QTL affecting these traits are still segregating. Future fine-mapping efforts could elucidate whether ancestral mutations are still segregating as a result of pleiotropic effects on fitness traits or whether this variation is due to new mutations.

Analysis of Variance↗
PubMed2003

Chronic bronchitis in immunocompromised patients: association with a novel Mycoplasma species.

Patients with primary antibody deficiency are prone to recurrent bronchitis, often caused by nonencapsulated Haemophilus influenzae and streptococcal infection. Productive cough often persists even after elimination of these organisms with antibiotics. During an investigation into the cause of unexplained chronic bronchitis in these patients, a novel Mycoplasma species (designated A39) was first isolated from the sputum of a man with X-linked agammaglobulinaemia. Screening of sputa from a further 45 patients with primary antibody deficiency showed that 10 were positive for a similar organism using culture and/or a polymerase chain reaction based on sequences within the 16S ribosomal RNA gene. A comparison of the sequence data showed that the organism was distinct from but similar to Mycoplasma pneumoniae and other closely related mycoplasmas found in humans and animals. Electron microscopy showed some unique morphological characteristics. Although respiratory symptoms improved after elimination of A39 from the sputum of the patient with X-linked agammaglobulinaemia, further work is needed to establish the organism as a pathogen.

Adult↗
PubMed2003

Quantitative trait locus detection in commercial broiler lines using candidate regions.

A QTL that explained a large proportion of the phenotypic difference between broiler and layer chickens in an experimental cross was evaluated in a commercial broiler line. A three-generation design, consisting of 15 grandsires, 608 half-sib hens, and more than 50,000 third-generation offspring, was implemented within the existing breeding scheme of a broiler breeding company. Four markers from a candidate region on chicken chromosome 4 were selected for their informativeness in the grandsires and used to genotype the first two generations. Using half-sib analyses, linkage was studied between these markers and 13 growth and carcass traits. The QTL analyses confirmed the presence of significant QTL for body weight (P < 0.01) and residual feed intake (P < 0.05) on chicken chromosome 4. Furthermore, evidence was found for QTL affecting the relative weight of bone and muscle in the thigh. Four more markers were added to increase resolution of the QTL positions. This increased the significance of the QTL for body weight (P < 0.001) and residual feed intake (P < 0.01) and showed evidence (P < 0.05) for additional QTL affecting carcass weight and conformation score. This study showed for the first time that a QTL that explains differences between broilers and layers was segregating in lines that have been selected for body weight over 50 generations. A possible explanation could be a pleiotropic or closely linked effect on fitness-related traits that are not part of the present study. The results demonstrate the feasibility of QTL detection and the potential for marker-assisted selection within a commercial broiler line without altering the existing breeding scheme.

Animals↗
PubMed2002

Quantitative trait loci affecting fatness in the chicken.

An F2 chicken population of 442 individuals from 30 families, obtained by crossing a broiler line with a layer line, was used for detecting and mapping Quantitative Trait Loci (QTL) affecting abdominal fat weight, skin fat weight and fat distribution. Within-family regression analyses using 102 microsatellite markers in 27 linkage groups were carried out with genome-wide significance thresholds. The QTL for abdominal fat weight were found on chromosomes 3, 7, 15 and 28; abdominal fat weight adjusted for carcass weight on chromosomes 1, 5, 7 and 28; skin and subcutaneous fat on chromosomes 3, 7 and 13; skin fat weight adjusted for carcass weight on chromosomes 3 and 28; and skin fat weight adjusted for abdominal fat weight on chromosomes 5, 7 and 15. Interactions of the QTL with sex or family were unimportant and, for each trait, there was no evidence for imprinting or of multiple QTL on any chromosome. Significant dominance effects were obtained for all but one of the significant locations for QTL affecting the weight of abdominal fat, none for skin fat and one of the three QTL affecting fat distribution. The magnitude of each QTL ranged from 3.0 to 5.2% of the residual phenotypic variation or 0.2-0.8 phenotypic standard deviations. The largest additive QTL (on chromosome 7) accounted for more than 20% of the mean weight of abdominal fat. Significant positive and negative QTL were identified from both lines.

Abdomen↗
PubMed2002

Mapping of quantitative trait loci for body weight at three, six, and nine weeks of age in a broiler layer cross.

An F2 chicken population was established from a cross of a broiler sire-line and an egg laying (White Leghorn) line. There were two males and two females from both lines in the base population. The F1 progeny consisted of 8 males and 32 females. Over 500 F2 offspring from five hatches were reared to slaughter at a live weight of 2 kg at 9 wk of age. Body weights at 3, 6, and 9 wk were recorded. The DNA was extracted from blood samples, and genotypes for 101 microsatellite markers were determined. Data of 466 individuals from 30 families were available for analysis. Interval mapping QTL analyses were carried out. The QTL significant at the genome wide level that affected body weight at two ages were identified on chromosomes 1, 2, 4, 7, and 8 and a QTL on Chromosome 13 influenced body weight at all three ages. Genetic effects were generally additive, and the broiler allele increased body weight in all cases. The effects for significant individual QTL accounted for between 0.2 and 1.0 phenotypic standard deviations and the sum of the additive effects accounted for approximately 0.75 of the line difference in body weight at 6 wk of age. The largest single additive effect was on chromosome 4, and the effect of substituting one copy of the gene was an increase in weight of 249 g. Interactions of the QTL with sex or family were unimportant. There was no evidence for imprinting or of two or more QTL at the same location for any of the traits.

Aging↗
PubMed2001

Treatment of resistant mycoplasma infection in immunocompromised patients with a new pleuromutilin antibiotic.

Patients with primary antibody deficiency (PAD) are prone to mycoplasma infection with unusual strains which may be resistant to conventional antibiotics. Mycoplasmas were isolated from the joint fluid (Ureaplasma urealyticum) of two PAD patients with arthritis and from the cerebral spinal fluid (Mycoplasma maculosum) in one with meningitis, the latter probably originating from the patient's dog. Combinations of doxycycline and quinolones or macrolides failed to clear the infections, but after demonstrating in-vitro sensitivity to the pleuromutilin, Econor, for two of the isolates, all three patients responded to oral treatment with Econor. The infection was completely eradicated in two patients, with the emergence of a resistant strain in the third. Mycoplasma infection should be considered in PAD patients with unexplained sepsis. Pleuromutilins such as Econor are powerful new anti-mycoplasmal agents which provide an additional therapeutic option when patients fail to respond to conventional antibiotics.

Adolescent↗
PubMed2000

Triterpene saponins in the defensive secretion of a chrysomelid beetle, Platyphora ligata.

The secretion of the defensive glands of adults of the chrysomelid beetle Platyphora ligata from Panama has been shown to contain, besides chlorogenic acid (1) and a mixture of phosphatidylcholines, two new oleanane triterpene saponins, named ligatosides A and B. Their structures were established as 3-O-beta-D-glucuronopyranosyl-16alpha,23-dihydroxyoleanol ic acid-28-O-2-(3,4-dimethoxybenzoyl)-beta-D-glucopyranoside (2) and 3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-16a lpha, 23-dihydroxyoleanolic acid-28-O-2-(3, 4-dimethoxybenzoyl)-beta-D-glucopyranoside (3), respectively, by a combination of extensive 1D and 2D NMR methods (COSY, HMQC, HMBC, and TOCSY) and FABMS. This is the first report of triterpene saponins in the defensive secretion of an insect.

Animals↗
PubMed2000

Triterpene saponins, quaternary ammonium compounds, phosphatidyl cholines, and amino acids in the pronotal and elytral secretions of Platyphora opima and Desmogramma subtropica.

Secretions of the pronotal and elytral glands of adults of the chrysomelid beetle Platyphora opima from Panama have been shown to contain two oleanane triterpene saponins: the known 3-O-beta-D-glucopyranosyl-(1-->3)-beta-D-glucuronopyranosyl-oleano lic acid-28-O-beta-D-glucopyranoside and compound 1, whose structure was established as 3-O-beta-D-glucopyranosyl-(1-->3)-beta-D-glucuronopyranosyl-29- hydrox yoleanolic acid-28-O-beta-D-glucopyranoside by a combination of 1D and 2D NMR methods (COSY, HMQC, HMBC, and TOCSY) and FABMS. The secretions also contained N,N,N-trimethylcadaverine and its 1, 2-dehydro derivative 3, as well as the nicotinamide derivative 4. Secretions of Desmogramma subtropica, also from Panama, contained as sole triterpene derivative 3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-24- hydrox yoleanolic acid (2), together with glutamic acid, glutamine, pyroglutamic acid, and arginine. A mixture of phosphatidylcholines was also present in the secretions of both species.

Amino Acids↗
PubMed2000

Integration of the genetic and physical maps of the chicken macrochromosomes.

A large amount of genetic mapping information has been obtained in the chicken from the East Lansing, Compton and Wageningen reference populations. Physical mapping information has however, been more limited. We have mapped 14 new clones, both genetically and physically, and all 14 have been assigned to macrochromosomes. The orientation of linkage groups E01C01C11W01 (Chr 1), E06C02W02 (Chr 2), E02C03W03 (Chr 3), E05C04W04 (Chr 4), E07E34C05W05 (Chr 5), E11C10W06 (Chr 6), E45C07W07 (Chr 7) and E43C12W11 (Chr 8) has been established. Here we present integrated maps of the eight macrochromosomes and the Z chromosome of the chicken and correlate genetic with physical distances for chromosomes 1-3 and the Z sex chromosome.

Animals↗
PubMed2000

Differences in gene density on chicken macrochromosomes and microchromosomes.

The chicken karyotype comprises six pairs of large macrochromosomes and 33 pairs of smaller microchromosomes. Cytogenetic evidence suggests that microchromosomes may be more gene-dense than macrochromosomes. In this paper, we compare the gene densities on macrochromosomes and microchromosomes based on sequence sampling of cloned genomic DNA, and from the distribution of genes mapped by genetic linkage and physical mapping. From these different approaches we estimate that microchromosomes are twice as gene-dense as macrochromosomes and show that sequence sampling is an effective means of gene discovery in the chicken. Using this method we have also detected a conserved linkage between the genes for serotonin 1D receptor (HTR1D) and the platelet-activating factor receptor protein gene (PTAFR) on chicken chromosome 5 and human chromosome 1p34.3. Taken together with its advantages as an experimental animal, and public access to genetic and physical mapping resources, the chicken is a useful model genome for studies on the structure, function and evolution of the vertebrate genome.

Animals↗
PubMed1999

The dynamics of chromosome evolution in birds and mammals.

Comparative mapping, which compares the location of homologous genes in different species, is a powerful tool for studying genome evolution. Comparative maps suggest that rates of chromosomal change in mammals can vary from one to ten rearrangements per million years. On the basis of these rates we would expect 84 to 600 conserved segments in a chicken comparison with human or mouse. Here we build comparative maps between these species and estimate that numbers of conserved segments are in the lower part of this range. We conclude that the organization of the human genome is closer to that of the chicken than the mouse and by adding comparative mapping results from a range of vertebrates, we identify three possible phases of chromosome evolution. The relative stability of genomes such as those of the chicken and human will enable the reconstruction of maps of ancestral vertebrates.

Animals↗
PubMed1992

Adipose tissue lipogenesis and fat deposition in leaner broiler chickens.

Rates of hepatic lipogenesis and secretion of plasma triglyceride-rich lipoproteins in 6- to 7-wk-old broiler chickens were similar to the overall rate of fat deposition in these birds, although approximately 20% of [14C]-labeled VLDL was oxidized to CO2 within 8 h. Only 6-7% of VLDL and portomicron triglyceride was taken up by the abdominal fat pad, but this proportion of total triglyceride flux could account for about 80-85% of the total fatty acids accumulating in that depot. The rate of lipogenesis in adipose tissue was much lower than that in the liver, but it could account for much of the remaining fatty acids. Lipogenesis from [14C]acetate in cultured chicken adipocytes was markedly inhibited by adding VLDL as an exogenous source of fatty acids. However, adipose tissue lipogenesis was not increased in vivo by reduction of plasma lipoprotein flux by genetic selection, by the feeding of a high protein diet or by immunological intervention. The results confirm that adipose tissue lipogenesis makes only a small contribution to adipose tissue growth in normal broilers. Its importance does not increase in response to the reductions in hepatic lipogenesis that accompany genetic or nutritional manipulation of body composition.

Adipose Tissue↗
PubMed1991

Changes in plasma lipoprotein metabolism in chicks in response to polychlorinated biphenyls (PCBs).

The results of the present study strongly suggest that the hypertriglyceridaemia in chicks treated with Aroclor 1254 is a result of reduction in VLDL clearance rather than an increase in rate of VLDL secretion. The decrease in post-heparin LPL activity responsible for reduced VLDL clearance may be mediated by cytokines produced by chronic activation of the immune system.

3-Hydroxybutyric Acid↗
PubMed1991

Why are young broiler chickens fatter than layer-strain chicks?

1. The abdominal fat pads of 5 week-old broiler and layer chicks incorporated 6.0 and 3.9% of intravenously-injected 14C-labelled very low density lipoproteins respectively. 2. These proportions of total plasma lipoprotein flux were sufficient to account for about 65-70% of the rate of fat deposition in broilers, but were more than 4-fold greater than that the rate of fat deposition in layers. 3. [14C]Palmitate taken up into adipose tissue of layer chicks had a t1/2 of 2-3 days. 4. There was no significant turnover of adipose tissue triglycerides in broilers and this appears to be a major reason for their relative fatness.

Adipose Tissue↗