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PubMed2025

Abiotic conditions can modify the penetrance of transgene-based lethality systems for insect population control.

Modern genetic biocontrol techniques for insect pest management, when compared to chemical insecticide spraying, offer high species specificity and reduced environmental impact, and some of these methods require the environmental release of genetically modified (GM) insects. Because organisms exposed to different environments often show variability in phenotype and gene expression, it is likely that GM insects will also experience environmentally mediated variation, potentially compromising pest control efficiency. This study examines the impact of temperature and nutrition on the early embryonic Tet-off conditional lethality system in Drosophila melanogaster. By independently manipulating parental and offspring environments, we assessed how exposure to variable environments influenced the probability of larval hatching and the transcript abundance of the transgenic system. Our findings revealed that: (i) transgene performance distinctly responds to temperature and nutrition; (ii) thermal stress has a greater impact when embryos, rather than parents, are exposed; and (iii) extreme nutritional conditions can markedly reduce the penetrance of transgenic lethality. Although changes in transgene transcript abundance were observed across environments, these changes did not fully explain the phenotypic variation, suggesting that factors downstream of transcription probably drive variation in transgenic lethality.

Animals↗
PubMed1990

Possible association of rare autosomal folate sensitive fragile sites and idiopathic mental retardation: a blind controlled population study.

The expression of folate sensitive fragile sites (FS) was assessed in cord blood lymphocyte cultures obtained from 790 newborns (NB) and in peripheral blood lymphocyte cultures from 326 institutionalized mentally retarded residents (MR). The mean rate of expression of common FS and the occurrence of rare FS was significantly higher in the MR population. Age, sex and history of chronic medication use did not appear to influence common FS expression in the MR population, 3/790 (0.38%) NB and 5/326 (1.53%) MR exhibited rare autosomal folate sensitive FS, a 4-fold difference in incidence (P = 0.009, Poisson test). Four of the five MR who expressed rare FS were considered to have idiopathic MR (4/179 or 2.2%). The occurrence of rare FS in 1/147 (0.68%) MR with known etiology is not significantly different from the frequency of occurrence in the NB population (P = 0.428, Poisson test). In this population, rare FS appear to be overrepresented in the idiopathic etiology MR group.

Abnormalities, Multiple↗
PubMed2000

Insect population control using a dominant, repressible, lethal genetic system.

A major modification to the sterile insect technique is described, in which transgenic insects homozygous for a dominant, repressible, female-specific lethal gene system are used. We demonstrate two methods that give the required genetic characteristics in an otherwise wild-type genetic background. The first system uses a sex-specific promoter or enhancer to drive the expression of a repressible transcription factor, which in turn controls the expression of a toxic gene product. The second system uses non-sex-specific expression of the repressible transcription factor to regulate a selectively lethal gene product. Both methods work efficiently in Drosophila melanogaster, and we expect these principles to be widely applicable to more economically important organisms.

Animals↗
PubMed1985

F-response behaviour in a control population.

Various parameters of the F-response including minimal and maximal latency, chronodispersion, amplitude (absolute and F%M) and duration have been determined for a sample of 20 responses in the median and ulnar nerves bilaterally in normal healthy subjects of both sexes aged between 12 to 81 years. Side to side comparisons revealed no significant differences in any of the parameters except for slightly longer minimum F latencies in the right median nerve. Strong correlations were found between minimal and maximal F latencies and height, while much weaker relationships were found between these parameters and age. There was a slight but significant relationship between F%M and age, but no age or sex related changes were noted for any of the remaining F-response parameters.

Adolescent↗
PubMed2002

Higher incidence of falls in long-term stroke survivors than in population controls: depressive symptoms predict falls after stroke.

BACKGROUND AND PURPOSE: The incidence of falls among noninstitutionalized individuals with long-standing stroke has not been examined previously, although fractures are more common and the consequences more severe for stroke patients than for elderly people in general. METHODS: For 4 months (September to December 1998), we followed 111 home-living patients who had suffered a stroke a mean of 10 years previously and 143 control subjects randomly selected from the same municipality, matched with respect to age and sex. Falls were registered daily by use of "fall calendars." Before the fall registration period, information about morbidity, use of medication, and activities of daily living had been registered. Height, weight, vision, blood pressure, motor function, and body sway had been measured, and depressive symptoms as well as cognitive function had been assessed. RESULTS: During follow-up, 23% of the patients and 11% of the control subjects fell once or more, and the risk of falling at least once was more than twice as high for the patients with stroke, when controlled for potential confounders (relative risk=2.2; 95% CI, 1.1 to 4.3). Among the stroke patients, depressive symptomatology predicted falls, and the relative risk for falling increased by 1.5 per standard deviation increase in the depression score. CONCLUSIONS: We conclude that falls are more frequent among noninstitutionalized long-term stroke survivors than among community control subjects and that the risk of falling and depressive symptoms are related in stroke patients.

Accidental Falls↗