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An explorative field study was conducted to assess residential exposure to pesticides, regularly applied in bulb farming. House dust floor samples were taken from homes of bulb farmers (n = 12) and from homes in close proximity to a bulb field (i.e. non-farmers) (n = 15). Samples were analysed for 7 pesticides used by bulb growers in the sampling period. Of these pesticides, chloropropham, flutolanil and vinchlozolin could be detected in non-farmers homes. All pesticides were detected in farmers' homes, except metamitron. Median concentrations for chloropropham were significantly higher in farmers' homes (0.05 vs.JP 2 , p = 0.03). Logistic regression analyses showed that the odds for detecting pesticides were higher in farmers' compared to non- farmers' homes and remained higher after correction for potential confounders. Results showed no significant effect of proximity of a residence to a bulb field for median concentrations of pesticides; however, logistic regression analysis showed a borderline statistically significant effect for detecting chloropropham above the detection limit (OR = 10, p = 0.08). These findings demonstrate that, as expected, risk of exposure is higher for bulb farmers than for non-farmers. They also indicate that exposure to pesticides is not limited to bulb farmers only, and this warrants further investigation.
In the yeast Saccharomyces cerevisiae, hexose transporter (Hxt) proteins transport glucose across the plasma membrane. The Hxt proteins are encoded by a multigene family with 20 members, of which Hxt1-4p and Hxt6-7p are the major hexose transporters. The remaining Hxt proteins have other or unknown functions. In this study, expression of HXT5 under different experimental set-ups is determined. In glucose-grown batch cultures, HXT5 is expressed prior to glucose depletion. Independent of the carbon source used in batch cultures, HXT5 is expressed after 24 h of growth and during growth on ethanol or glycerol, which indicates that growth on glucose is not necessary for expression of HXT5. Increasing the temperature or osmolarity of the growth medium also induces expression of HXT5. In fed-batch cultures, expression of HXT5 is only observed at low glucose consumption rates, independent of the extracellular glucose concentration. The only common parameter in these experiments is that an increase of HXT5 expression is accompanied by a decrease of the growth rate of cells. To determine whether HXT5 expression is determined by the growth rate, cells were grown in a nitrogen-limited continuous culture, which enables modulation of only the growth rate of cells. Indeed, HXT5 is expressed only at low dilution rates. Therefore, our results indicate that expression of HXT5 is regulated by growth rates of cells, rather than by extracellular glucose concentrations, as is the case for the major HXTs. A possible function for Hxt5p and factors responsible for increased expression of HXT5 upon low growth rates is discussed.
Linoleic acid and α-linolenic acid are essential fatty acids (eFAs) and have to be acquired from the diet. eFAs are the precursors for long-chain polyunsaturated fatty acids (lcPUFAs), which are important immune-modulating compounds. lcPUFAs can be converted into eicosanoids and other mediators. They affect membrane structure and fluidity and can alter gene expression. There has been a marked change in dietary fatty acid intake over the last several decades. Since eFAs are acquired from the diet and immune development occurs mainly perinatally, the maternal diet may influence fetal and neonatal eFA levels, and thereby lcPUFA status, and thus immune development and function. To study whether early exposure to eFAs can program immune function, mice were fed diets varying in the ratio of ω-3 to ω-6-eFAs during pregnancy and/or lactation. After weaning, pups received a Western-style diet. At 11 weeks of age, the effects of maternal diet on the offspring's allergic and vaccination responses were examined using the T-helper 2 driven ovalbumin-induced allergy model and the T-helper 1 driven influenza-vaccination model, respectively. Offspring of dams fed a high α-linolenic acid diet during lactation showed an enhanced vaccination response. As diets with either low or high ω-3/ω-6-eFA ratio attenuated the T-helper 2 allergic response, the high α-linolenic acid diet fed during lactation had the most pronounced effect. These results indicate that there is a programming effect of maternal diet on the offspring's immune response and that in mice the window of greatest susceptibility to maternal dietary intervention is the lactation/suckling period.
The focus of attention in immunology has classically been the adaptive immune system. The adaptive immune system is most effective when the host has had prior exposure to the pathogen. Accruing evidence suggests that the innate immune system plays an important role in the regulation of the adaptive immune response and in filling the temporal gap in host immunity. Pattern recognition molecules such as collectins are important components of the innate immune system. Herein we describe the structural aspects and immunological functions of the two lung collectins surfactant protein A (SP-A) and SP-D. Important clinical applications of pulmonary collectin research include the use of SP-A and -D in diagnosis and therapy. This survey focuses on the interactions of SP-A and -D with a wide variety of respiratory pathogens and the regulation of the immune cell response by these collectins.
Background Pregnancy is a portentous stage in life, during which countless events are precisely orchestrated to ensure a healthy offspring. Maternal microbial communities are thought to have a profound impact on development. Although antibiotic drugs may interfere in these processes, they constitute the most frequently prescribed medication during pregnancy to prohibit detrimental consequences of infections. Gestational antibiotic intervention is linked to preeclampsia and negative effects on neonatal immunity. Even though perturbations in the immune system of the mother can affect reproductive health, the impact of microbial manipulation on maternal immunity is still unknown. Aim To assess whether antibiotic treatment influences maternal immunity during pregnancy. Methods Pregnant mice were treated with broad-spectrum antibiotics. The maternal gut microbiome was assessed. Numerous immune parameters throughout the maternal body, including placenta and amniotic fluid were investigated and a novel machine-learning ensemble strategy was used to identify immunological parameters that allow distinction between the control and antibiotic-treated group. Results Antibiotic treatment reduced diversity of maternal microbiota, but litter sizes remained unaffected. Effects of antibiotic treatment on immunity reached as far as the placenta. Four immunological features were identified by recursive feature selection to contribute to the most robust classification (splenic T helper 17 cells and CD5 + B cells, CD4 + T cells in mesenteric lymph nodes and RORγT mRNA expression in placenta). Conclusion In the present study, antibiotic treatment was able to affect the carefully coordinated immunity during pregnancy. These findings highlight the importance of inclusion of immunological parameters when studying the effects of medication used during gestation.
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