Atopy and occupational asthma

Summary We evaluated atopy in 206 white collars and housewives with seasonal and perennial respiratory symptoms and in 58 workers occupationally exposed to isocyanate and flour with symptoms at work. Atopy was much less common among people with symptoms at work, but there was no significant difference in the frequency of atopics between varnishers and bakers. Self selection of atopic employees who leave their job because of respiratory symptoms may account for these results, but further studies are needed to clarify the relationship between atopic status and occupational asthma.     

Cytoplasmic inheritance and its implications for animal biotechnology

At fertilization, the mammalian sperm transmits the haploid paternal genome. However, it also carries a variety of other factors into the oocyte that have the potential to affect embryo development. These include mRNAs left over from spermatogenesis, mitochondria with their own DNA, cytoskeletal and contractile elements, remnants of the sperm plasma membrane and, in many species, the sperm centriole. While most of these elements are eliminated, some play essential roles in early embryogenesis. In this review, I summarize the latest information on these phenomena and indicate some of the implications for animal biotechnology and, in particular, cloning.     

Oligodontia and its inheritance in Kerry blue terrier

Defects of the premolar tooth formula (oligodontia, tooth number reduction) were studied in dogs of the Kerry blue terrier breed. For this purpose, a database including 480 individuals of 96 litters was constructed. The occurrence of oligodontia was investigated in pedigree groups with inbred and outbred crosses. No selective mating choice for the anomaly under study was found in the sample. The results indicate that oligodontia is inherited, which requires comprehensive study of its genetic control and search for corresponding genes.     

Tolerance to ryegrass mosaic virus and its inheritance

Plant yield within and between four cultivars of perennial ryegrass infected with ryegrass mosaic virus (RMV) was closely related to symptom severity. Distribution of symptom severity was continuous in four perennial ryegrass and four Italian ryegrass cultivars infected with a severe RMV isolate, and also in another perennial ryegrass cultivar infected with a severe isolate of the virus, a mild one and one of intermediate severity. Symptom expression was polygenically inherited in both Italian (cv. RvP) and perennial (cv. S.24) ryegrass. Both additive and non-additive genetic variation was present in RvP, but the variation in S.24 was additive only. No significant maternal inheritance was present in either species.     

Atopy and immunoglobulin E concentrations in Hodgkin's disease and other lymphomas.

Serum immunoglobulin E (IgE) concentrations are increased in Hodgkin''s disease (HD) but not in other types of lymphoma. The prevalence of atopic disease is similar to normal in both groups. Patients with high IgE concentrations and HD were separated into atopic and non-atopic groups, which were found to differ clinically. Atopic patients had a significantly lower incidence of night sweats, fever, and weight loss, and treatment had no significant lasting effect on their IgE concentrations. In the non-atopic group there was a striking correlation between high IgE concentrations and a histological appearance of nodular sclerosis, particularly in the presence of night sweats, fever, and weight loss. Successful treatment in the non-atopic group led to a noticeable fall in IgE concentrations, in most cases to normal, though on relapse of the disease they rose again.     

The Mexican hairless dog, its morphology and inheritance

Some morphological characteristics of the Mexican hairless dog and their inheritance were investigated. The dogs examined were hairless and had defective teeth. From the results of mating experiments, an autosomal dominant semi-lethal gene was considered to be responsible for the hairlessness accompanied by defective teeth in the dog. The possible usefulness of the dog was also discussed.     

Penicillin production and its mode of inheritance inAspergillus nidulans

Previous workers have shown that some strains ofAspergillus nidulans produce penicillin-like substances. In the present studies, shake-flask cultures of 101 wild-type strains ofA. nidulans, representatives of 18 different heterokaryon-compatible groups, were examined and filtrates of most found to inhibit the growth of a strain ofBacillus subtilis sensitive to penicillin, although members of two of these groups had no detectable antibiotic activity. Five strains with antibacterial properties were chosen for detailed investigation as well as two genetically labelled derivatives obtained from one of these after ultraviolet light treatments; one derivative had a similar antibiotic yield to its original wild-type parent but the other was selected as having increased antibiotic yield. The antibiotic produced by these seven strains was by all tested criteria, including chromatographic and electrophoretic behaviour, indistinguishable from penicillin. A heterokaryon test between the two mutants indicated that antibiotic productivity was under nuclear control.     

Differential rRNA genes expression in bread wheat and its inheritance

The expression of the ribosomal RNA (rRNA) genes from rye, located within the nucleolus organizer regions (NORs), is repressed by cytosine methylation in wheat x rye hybrids and in triticale, as consequence of nucleolar dominance. Our previous study revealed that bread wheat cultivars with a maximum number of four Ag-NORs presented high level of rDNA cytosine methylation when compared to others with a maximum of six Ag-NORs. In order to evaluate the inheritance of the Ag-NORs number and NOR methylation patterns, we produced F₁ hybrids between bread wheat cultivars with four Ag-NORs and bread wheat cultivars with six Ag-NORs (in the direct and reciprocal senses). The F₂ progenies of these F₁ hybrids were also evaluated for the NOR number and methylation patterns. Parent bread wheat cultivars with a maximum of four Ag-NORs after treated with 5-azacytidine evidenced a maximum of six Ag-NORs per metaphase cell and a maximum of six nucleoli per interphase nucleus, confirming that the expression of the rRNA genes in bread wheat is related to cytosine methylation. Most of the F₁ hybrids showed a maximum number of four or six Ag-NORs, similarly to that of the female parent suggesting a non-mendelian inheritance, while other hybrids presented four or six Ag-NORs in both senses of the cross. The F₁ NOR methylation patterns showed some fragments common to their parents but also novel fragments suggesting genomic and/or chromosome rearrangements after hybridization. Despite the different NOR patterns among the parents, an invariable NOR pattern was found among the F₁ plants suggesting a tendency to stability, which was also transmitted to the F₂. The F₂ progenies showed plants with a maximum of four, five and/or six Ag-NORs. The ratio of plants with four, five and/or six Ag-NORs per F₂ progeny was variable and did not follow any specific mendelian proportion. These results allowed us to suggest that the inheritance of the number of Ag-NORs by the F₁ and F₂ plants did not follow any mendelian inheritance and were not correlated to NOR methylation patterns in contrast to what was verified for their parents.     

Complex inheritance and localizing disease genes.

Most methods for localizing genes underlying complex traits work under the implicit or explicit assumption of a single disease gene with the possible exception of heterogeneity, that is, different disease genes in different families. We discuss current single-locus and multi-locus methods. Novel approaches are proposed that take into account all marker loci over the genome. A simple example is given for an unconventional statistic, i.e. the mean of allele sharing over all markers on a chromosome.     

Atopy does not predispose to RSV bronchiolitis or postbronchiolitic wheezing.

Twenty-six 8-year-old children who had had respiratory syncytial virus (RSV) bronchiolitis in infancy and their paired controls underwent skin and blood tests to assess the role of immunodeficiency and atopy in the pathogenesis of RSV bronchiolitis and the wheezing that may follow it. There was no difference between patients and controls in prevalence of atopy; positive results of prick tests to common antigens; eosinophil counts; yeast opsonisation defect; C2 deficiency; IgG, IgA, IgM, and IgE concentrations; or IgE antibody to dermatophagoides, timothy-grass pollen, and cat fur. Those of the children who had had RSV bronchiolitis and who continued to wheeze had a slightly higher mean eosinophil count and levels of IgE antibody to dermatophagoides than those who did not wheeze. Exercise-induced bronchial lability, though higher in patients than controls, did not correlate significantly with eosinophil counts or IgE concentrations. The genetic factors predisposing to RSV bronchiolitis and postbronchiolitic wheezing may differ from those predisposing to atopic asthma, though exclusive breast feeding may protect against both.     

Lipoprotein(a): its inheritance and molecular basis of its atherothrombotic role

Lipoprotein(a) or Lp(a), is a member of the plasma lipoproteins with general properties of LDL but with a protein moiety represented by apoB100 disulfide linked to apolipoprotein(a) or apo(a). Apo(a) is polymorphic in size; at present a total of 11 isoforms have been reported, but more are likely to be identified in view of the fact that at least 19 alleles of the apo(a) gene have recently been reported. There are remarkable variations in the plasma Lp(a) levels; but uncertainties still exist about the factors responsible for this variability. High plasma Lp(a) levels have been associated with an increased incidence of cardiovascular disease, mainly based on epidemiological evidence. Both atherogenic and thrombogenic potentials have been suggested; the first attributable to the LDL-like properties of Lp(a) and the other to the plasminogen-like characteristics of apo(a). From the mechanistic viewpoint in vitro studies suggest that the thrombogenic action may occur at the level of the endothelium whereas Lp(a) that localizes in the sub-endothelial intima is expected to undergo complexation with matrix components and favor the formation of the atherosclerotique plaque. How Lp(a) polymorphism relates to the postulated cardiovascular pathogenicity of this lipoprotein remains to be established.     

Multifactorial inheritance with cultural transmission and assortative mating. II. a general model of combined polygenic and cultural inheritance.

A general linear model of combined polygenic-cultural inheritance is described. The model allows for phenotypic assortative mating, common environment, maternal and paternal effects, and genic-cultural correlation. General formulae for phenotypic correlation between family members in extended pedigrees are given for both primary and secondary assortative mating. A FORTRAN program BETA, available upon request, is used to provide maximum likelihood estimates of the parameters from reported correlations. American data about IQ and Burks' culture index are analyzed. Both cultural and genetic components of phenotypic variance are observed to make significant and substantial contributions to familial resemblance in IQ. The correlation between the environments of DZ twins is found to equal that of singleton sibs, not that of MZ twins. Burks' culture index is found to be an imperfect measure of midparent IQ rather than an index of home environment as previously assumed. Conditions under which the parameters of the model may be uniquely and precisely estimated are discussed. Interpretation of variance components in the presence of assortative mating and genic-cultural covariance is reviewed. A conservative, but robust, approach to the use of environmental indices is described.