Molecular basis for the dominant white phenotype in the domestic pig

The change of phenotypic traits in domestic animals and crops as a response to selective breeding mimics the much slower evolutionary change in natural populations. Here, we describe that the dominant white phenotype in domestic pigs is caused by two mutations in the KIT gene encoding the mast/stem cell growth factor receptor (MGF), one gene duplication associated with a partially dominant phenotype and a splice mutation in one of the copies leading to the fully dominant allele. The splice mutation is a G to A substitution in the first nucleotide of intron 17 and leads to skipping of exon 17. The duplication is most likely a regulatory mutation affecting KIT expression, whereas the splice mutation is expected to cause a receptor with impaired or absent tyrosine kinase activity. Immunocytochemistry showed that this variant form is expressed in 17- to 19-day-old pig embryos. Hundreds of millions of white pigs around the world are assumed to be heterozygous or homozygous for the two mutations. [The EMBL accession numbers for porcine KIT1*0101, KIT1*0202, KIT2*0202, and KIT2*0101 are AJ223228-AJ223231, respectively.]

Mapping quantitative trait loci for immune capacity in the pig

Immune capacity traits show considerable genetic variation in outbred populations. To identify quantitative trait loci (QTLs) for immune capacity in the pig, various measures of immune function (total and differential leukocyte counts, neutrophil phagocytosis, mitogen-induced proliferation, IL-2 production, and virus induced IFN-alpha production in whole blood cultures, and Ab responses to two Escherichia coli antigens) were determined in 200 F2 animals from a wild pig-Swedish Yorkshire intercross. The pedigree has been typed for 236 genetic markers covering all autosomes, the X chromosome and the X/Y pseudoautosomal region. Through interval mapping using a least-squares method, four QTLs with significant effects were identified; one for total leukocyte counts, one for mitogen-induced proliferation, one for prevaccination levels of Abs to E. coli Ag K88, and one for Ab response to the O149 Ag. In addition, several putative QTLs were indicated. The results from the present study conclusively show that it is possible to identify QTLs for immune capacity traits in outbred pig populations by genome analysis.

An immunohistochemical study on the postnatal changes in the C-terminal flanking peptide of neuropeptide Y (CPON)--positive nerve fibers in pineal gland of the pig

Postnatal development of innervation of the porcine pineal gland by C-terminal flanking peptide of neuropeptide Y (CPON)-immunoreactive nerve fibers was examined using the immunohistochemical technique. CPON-positive nerve fibers appeared in the pineal gland of the new-born piglets and formed plexus in the capsula and connective tissue septa of the gland. The nerve terminals branched off from the plexus and penetrated into adjacent parenchyma. The number of nerve fibers immunoreactive to CPON in parenchyma is very low in new-born and 20-day-old piglets. In 7-month-old pigs they created a dense network.

Immunohistochemical and cytochemical localization of the somatostatin receptor subtype sst1 in the somatostatinergic parvocellular neuronal system of the rat hypothalamus

Somatostatin is known to mediate its actions through five G-protein-coupled receptors (sst1-sst5). We have studied the expression of the sst1 receptor in the rat hypothalamus by using a subtype-specific antiserum. In Western blotting, the antiserum reacted specifically with a band with an apparent molecular weight of 80,000 in membranes prepared from hypothalamic tissue. The localization of the sst1 receptor was investigated by immunohistochemistry in hypothalamus sections. Additionally, an immunofluorescent double-labeling was performed for the sst1 receptor and somatostatin. Light microscopy revealed that the sst1 receptor is located in perikarya and nerve fibers in the rostral periventricular area surrounding the third ventricle as well as in nerve fibers projecting from the perikarya to the external layer of the median eminence. In these neuronal structures, sst1 immunoreactivity was found to be colocalized with somatostatin. Furthermore, the location of sst1 receptors was studied by immunoelectron microscopy in the median eminence. In the external layer, receptor immunoreactivity was confined to nerve terminals. Immunoreactive nerve terminals were seen to make synapse-like junctions with other both stained and unstained nerve terminals. Thus, the sst1 receptor is present in the classic somatostatinergic hypothalamic parvocellular system inhibiting hormone secretion from the anterior pituitary gland. These findings indicate that the sst1 receptor may act as an autoreceptor and inhibit the release of somatostatin from periventricular neurons projecting to the median eminence.

Multiple marker mapping of quantitative trait loci in a cross between outbred wild boar and large white pigs

A quantitative trait locus (QTL) analysis of growth and fatness data from a three generation pig experiment is presented. The population of 199 F2 animals was derived from a cross between wild boar and Large White pigs. Animals were typed for 240 markers spanning 23 Morgans of 18 autosomes and the X chromosome. A series of analyses are presented within a least squares framework. First, these identify chromosomes containing loci controlling trait variation and subsequently attempt to map QTLs to locations within chromosomes. This population gives evidence for a large QTL affecting back fat and another for abdominal fat segregating on chromosome 4. The best locations for these QTLs are within 4 cM of each other and, hence, this is likely to be a single QTL affecting both traits. The allele inherited from the wild boar causes an increase in fat deposition. A QTL for intestinal length was also located in the same region on chromosome 4 and could be the same QTL with pleiotropic effects. Significant effects, owing to multiple QTLs, for intestinal length were identified on chromosomes 3 and 5. A single QTL affecting growth rate to 30 kg was located on chromosome 13 such that the Large White allele increased early growth rate, another QTL on chromosome 10 affected growth rate from 30 to 70 kg and another on chromosome 4 affected growth rate to 70 kg.

Annual variations of the NPYergic innervation of the pineal gland in the European hamster (Cricetus cricetus): a quantitative immunohistochemical study

A prominent innervation of the pineal gland of the European hamster with nerve fibres containing neuropeptide Y (NPY) and tyrosine hydroxylase (TH) was demonstrated by means of immunohistochemistry. Nearly all the TH- and NPY-immunoreactive nerve fibres in the superficial pineal gland disappeared after bilateral superior cervical ganglionectomy, showing that the majority of NPY- and TH-immunoreactive nerve fibres belonged to the sympathetic nervous system. Since, in the European hamster, preliminary studies of the NPY-fibre density in the pineal gland had indicated seasonal changes, the density of NPY-immunoreactive nerve fibre profiles was ascertained in the superficial pineal gland in a series of animals between the first part of November and late April. The highest density of NPY-immunoreactive nerve fibre profiles was observed during midwinter. On the other hand, during the same period of the year, the number of sympathetic TH-immunoreactive sympathetic nerve fibre profiles did not exhibit seasonal variation, nor did substitution of testosterone, during the sexually inactive period, affect the density of NPY-containing nerve fibres in the gland. Our results show the presence of a testosterone-independent annual variation in the content of NPY in the sympathetic nerve fibres innervating the pineal gland of the European hamster. This variation can be correlated with the changes in the daily pattern of melatonin production observed by others in the same species at this period of the year.

Mapping quantitative trait loci for carcass and meat quality traits in a wild boar x Large White intercross

An intercross between wild boar and a domestic Large White pig population was used to map quantitative trait loci (QTL) for body proportions, weight of internal organs, carcass composition, and meat quality. The results concerning growth traits and fat deposition traits have been reported elsewhere. In the present study, all 200 F2 animals, their parents, and their grandparents were genotyped for 236 markers. The marker genotypes were used to calculate the additive and dominance coefficients at fixed positions in the genome of each F2 animal, and the trait values were regressed onto these coefficients in intervals of 1 cM. In addition, the effect of proportion of wild boar alleles was tested for each chromosome. Significant QTL effects were found for percentage lean meat and percentage lean meat plus bone in various cuts, proportion of bone in relation to lean meat in ham, muscle area, and carcass length. The significant QTL were located on chromosomes 2, 3, 4, and 8. Each QTL explained 9 to 16% of the residual variance of the traits. Gene action for most QTL was largely additive. For meat quality traits, there were no QTL that reached the significance threshold. However, the average proportion of wild boar alleles across the genome had highly significant effects on reflectance and drip loss. The results show that there are several chromosome regions with a considerable effect on carcass traits in pigs.

Origin and relationships of Saintpaulia (Gesneriaceae) based on ribosomal DNA internal transcribed spacer (ITS) sequences

Phylogenetic relationships of eight species of Saintpaulia H. Wendl., 19 species of Streptocarpus Lindl. (representing all major growth forms within the genus), and two outgroups (Haberlea rhodopensis Friv., Chirita spadiciformis W. T. Wang) were examined using comparative nucleotide sequences from the two internal transcribed spacers (ITS) of nuclear ribosomal DNA. The length of the ITS 1 region ranged from 228 to 249 base pairs (bp) and the ITS 2 region from 196 to 245 bp. Pairwise sequence divergence across both spacers for ingroup and outgroup species ranged from 0 to 29%. Streptocarpus is not monophyletic, and Saintpaulia is nested within Streptocarpus subgenus Streptocarpella. Streptocarpus subgenus Streptocarpus is monophyletic. The ITS sequence data demonstrate that the unifoliate Streptocarpus species form a clade, and are also characterized by a unique 47-bp deletion in ITS 2. The results strongly support the monophyly of (1) Saintpaulia, and (2) Saintpaulia plus the African members of the subgenus Streptocarpella of Streptocarpus. The data suggest the evolution of Saintpaulia from Streptocarpus subgenus Streptocarpella. The differences in flower and vegetative characters are probably due to ecological adaptation leading to a relatively rapid radiation of Saintpaulia.

Localization and diurnal expression of mRNA encoding the beta1-adrenoceptor in the rat pineal gland: an in situ hybridization study

The rat pinealocyte is stimulated by norepinephrine, which is released from sympathetic nerve fibers innervating the gland. Norepinephrine binds to beta1-adrenoceptors situated on the pinealocyte cell membrane. Ligand binding to these receptors exhibits a diurnal rhythm, with the largest number occurring in the late part of the light phase when the release of norepinephrine is minimal. By using in situ hybridization with a cDNA antisense oligonucleotide probe recognizing mRNA encoding the rat beta1-adrenoceptor, we have demonstrated a stronger hybridization signal in the rat pineal gland than in other brain regions. Cells containing beta1-mRNA are located in the superficial pineal gland, the deep pineal gland, and the pineal stalk. However, the number of receptors varies considerably between the individual pinealocytes. The beta1-mRNA in situ hybridization signal for mRNA encoding the beta1-adrenoceptor of the rat pineal has been quantified over a 24-h period; the strongest signal is found at mid-dark and the weakest signal at mid-light, indicating that the transcriptional regulation of beta1-mRNA synthesis in the rat pineal is diurnal. In addition, maximal receptor protein expression occurs late in the light phase in the rat pineal and is thus considerably delayed compared with its peak mRNA synthesis. This lag time indicates that the beta1-receptor is regulated at the translational or post-translational level. Removal of the sympathetic input to the pineal gland by superior cervical ganglionectomy decreases the beta1-mRNA signal in the gland.

[Effect of gene dosage on the glyceraldehyde-3-phosphate dehydrogenase enzyme (GAPD) in partial 12p13.3 pter trisomy]

A family with three brothers presenting 12p trisomy due to an adjacent-1 segregation of a paternal translocation (1;12) (q44;p12.2) is described. The patient's phenotype was compatible with the chromosomal imbalance including the gene dosage effect of the glyceraldehyde-3-phosphate dehydrogenase. The importance of the genetic counseling in these families is stressed.

Carbohydrate reactivation of thyroxine 5'-deiodinase (type II) in cultured mouse neuroblastoma cells is dependent upon new protein synthesis

The T3 concentration in brain predominantly reflects local production from T4 rather than T3 uptake from the circulating pool. We recently demonstrated that rat brain T3 content is increased by glucose feeding compared to chow feeding. One possible mechanism for this effect is an increase in brain T4 5'-deiodinase (5'-D) activity. Our recent preliminary studies of neuroblastoma (NB) cells demonstrate that renewal of RPMI-1640 medium stimulates T4 5'-D type II (NB T4 5'-D II) activity in these cells. The present studies were performed to determine the mechanism of this response. Studies were performed on NB cells supported in thyroid hormone-depleted (deficient) medium. This approach increased NB T4 5'-DII activity 4-fold compared to that in thyroid hormone-replete medium. Medium renewal further stimulated enzyme activity (7- to 9-fold; maximum at 6 h) in each group. The difference between the hypothyroid group and control was sustained over a 24-h period. Subsequent studies demonstrated that glucose (11 mM) was the specific medium ingredient mediating the medium renewal response. A progressive increase in NB T4 5'-DII activity was noted over 8 h during RPMI-1640 salt plus glucose (11 mM) incubation. This was equivalent to the effect of complete medium containing glucose (11 mM). Coincubation with insulin (10(-7)-10(-9) M) did not modify the enzyme response to glucose. In addition, fructose (10 mM) had a similar effect on enzyme activity. Glycerol and essential and nonessential amino acids also modestly increased NB T4 5'-DII activity compared to that in the control group (P less than 0.01). Actinomycin-D (1 microM), cycloheximide (100 microM), and puromycin (100 microM) significantly (P less than 0.001) decreased the glucose effect on T4 5'-DII by 5-, 9-, and 17-fold, respectively, after 6 h of incubation. In addition, puromycin (10-200 microM) inhibited both NB T4 5'-DII activity and [3H]amino acid incorporation during incubation in glucose. There was a significant correlation between these parameters (r = 0.8; P less than 0.001). The enzyme activity decay curves in the glucose-activated and control groups subsequent to puromycin (100 microM) addition at 8 h were parallel. The fractional turnover rate was 13%/h in the controls and 11%/h in the glucose groups. The calculated enzyme production rate was significantly higher (P less than 0.005) in the glucose group compared to that in the control group (17.4 vs. 6.8 fmol/mg protein.h).(ABSTRACT TRUNCATED AT 400 WORDS)

inv(5)(p13q13) in a four generation pedigree

A 4 1/2 years old boy was found to have hypoplasia of the pectoralis major right muscle and a karyotype 46,XY,inv(5)(p13q13)mat. This inversion, probably independent of the boy's malformation, was present in at least four generations and it seems neither to impair fertility nor to yield viable recombinants.

Autosomal dominant piebaldism and mental retardation syndrome associated with a t(1;2) (p22.1;q36)

A syndrome of piebaldism and mild to moderate mental retardation was present in 3 sibs and their father. Besides, the disorder was segregating concordantly with a t(1;2) (p22.1;q36). It is concluded that the syndrome is due, either by gene breakage or dysfunction, to the translocation.

Trisomy 6qter resulting from a familial (6;10) (q23;q26) translocation

An infant deceased at 2 months of age was found to have a 46,XY,-10, +der(10),t (6;10) (q23;q26) mat karyotype. Since the clinical findings were similar to those of the trisomy 6qter syndrome, the present observation agrees with the assignment of the 6q23----qter segment as the pathogenetic determiner of this entity.

De novo del(4) (p15.32) with incomplete expression of the Wolf-Hirschhorn syndrome

A 7 7/12-year-old girl with a de novo deletion 4p15.32----pter without the typical Wolf-Hirschhorn syndrome (WHS) is presented. This observation and others from medical literature suggest that monosomy 4p15.31----4p15.32, rather than 4p16, is the cause of the typical WHS.

Monosomy 13q32.3----qter: report of two cases

Two unrelated patients with monosomy 13q32.3----qter are reported. Comparison with six similar cases previously published indicates that the craniofacial dysmorphism of the 13qter monosomy syndrome is related to band 13q34, the thumb hypoplasia to band 13q32, and an apparently different phenotype to band 13q33. Coagulation deficiency appears to be non-specific in monosomy 13qter.

Familial inv(2) (p2300q11.2)

A hitherto undescribed inv(2) (p2300q11.2) was found in 2 generations of a family ascertained through a holoprosencephalic liveborn boy with normal karyotype. This inversion, quite probably not related to the child malformations, does not seem neither impair reproductive fitness nor to yield viable recombination aneusomies.

Pure monosomy and trisomy 2q24.2----q3105 due to an inv ins(7;2)(q21.2;q3105q24.2) segregating in four generations

An inv ins(7;2)(q21.2;q3105q24.2) was found to segregate through four generations of a family. Adjacent-1 segregation aneusomies were ascertained in five patients: three monosomics and two trisomics; and the corresponding syndromes were delineated. The comparative analysis between these and other previously described 2q aneusomic individuals led to the conclusion that a large cleft between first and second toes is a constant feature in monosomy 2q24----q31. No other trait could plausibly be mapped. Risks of 7.9 to 31.6% for aneusomic children and of 26.3% for abortion were estimated in the present family.

Familial inv(1) (p3500q21.3) associated with azoospermia

An inv(1) (p3500q21.3) was found in an azoospermic man, his mother and two other maternal relatives. Although the mechanisms involved are still unclear, it is stressed that pericentric inversions of chromosome 1 in which the inverted chromosome becomes submetacentric (centromeric index less than or equal to 0.324) apparently impair spermatogenesis.

[Role of radiotherapy in the treatment of bladder cancer. Comments apropos of 178 cases]

In the light of their experience involving 178 patients suffering from carcinoma of the bladder and a study of the literature, the authors attempt to determine the role of radiotherapy in the treatment of carcinoma of the bladder. A number of points emerge: --the possibility of stopping the progression of a recurrent multifocal superficial malignant tumour by 2 flashes of 6.5 Gy; --the efficacy of curative doses of radiotherapy associated with transurethral resection of the tumour in 20% of cases. These figures rise to 50% in anaplastic carcinomas. 20% efficacy of radiotherapy alone without surgery is a high figure. It tends to restore the radiotherapy sensitivity test suggested by R. Couvelaire to its true value; --when combined with excision surgery (partial cystectomy or total prostato-cystectomy), high doses of radiation do not give a better result than limited radiation. In view of the gravity of radiotherapy complications which may occur in up to 20% of cases where high doses of radiation have been administered, the authors would be inclined to limit radiotherapy when treatment of the tumour must be mixed, with surgery. A preoperative flash of 6.5 Gy followed by postoperative radiotherapy up to a total of 45 Gy when partial cystectomy is used. When a decision is made to perform cutaneous implantation of the ureters, the technique should consist of concentrated radiotherapy of 20 Gy in one week followed by excision by total prostato-cystectomy the next week. When urinary bypass is to involve uretero-colonic implantation or bladder replacement, flash radiotherapy of 6.5 Gy once or twice. No additional postoperative radiotherapy. Sandwich radiotherapy is too dangerous.