Biologic markers in ethylene oxide-exposed workers and controls

Ethylene oxide (EtO) is an alkylating agent and a model direct-acting mutagen and carcinogen. This study has evaluated a panel of biologic markers including EtO-hemoglobin adducts (EtO-Hb), sister-chromatid exchanges (SCEs), micronuclei, chromosomal aberrations (CAs), DNA single-strand breaks (SSB) and an index of DNA repair (ratio of UDS to NA-AAF-DNA binding) in the peripheral blood cells of 34 workers at a sterilization unit of a large university hospital and 23 controls working in the university library. Comprehensive environmental histories were obtained on each subject including detailed occupational and smoking histories. Industrial hygiene data obtained prior to the study and personal monitoring during the 8 years preceding the study showed that workers were subject to low-level exposure near or below the current Occupational Safety and Health Administration (OSHA) standard of 1 ppm (TWA). Personal monitoring data obtained during 2 weeks prior to blood sampling were uniformly less than 0.3 ppm (TWA). After adjusting for smoking, EtO workplace exposure was significantly (p less than 0.001) associated with EtO-Hb (a carcinogen-protein adduct) and 2 measures of SCEs [the average number of SCEs/cell (SCE50) and the number of high frequency cells (SCEHFC)]. There was an apparent suppression of DNA repair capacity in EtO-exposed individuals as measured by the DNA repair index; i.e., the ratio of unscheduled DNA synthesis (UDS) and NA-AAF-DNA binding (p less than 0.01). No association of DNA repair index with smoking was found. Another important finding of this study is the highly significant correlation between EtO-Hb adduct levels and SCEHFC (p less than 0.01) and SCEs (p less than 0.02) which provides evidence of a direct link between a marker of biologically effective dose and markers of genotoxic response. In contrast, micronuclei, CAs and SSBs were not significantly elevated in the workers. The activity of the u-isoenzyme of glutathione-S-transferase (GT) was measured as a possible genetic marker of susceptibility and a modulator of biomarker formation. However, possibly because of confounding by age, no significant relationships were found between GT and any of the exposure-related markers by ANOVA or among other independent variables by regression. This study demonstrates significant effects of low-level EtO exposure, independent of smoking history, near or below 1 ppm on multiple biomarkers and suggests that the current OSHA standard may not be adequately protective. Previously described effects of smoking on EtO-Hb adducts, SCEs and SCEHFC were also seen in this study.(ABSTRACT TRUNCATED AT 400 WORDS)     

A robust KASP marker for selection of four pairs of linked leaf rust and stripe rust resistance genes introgressed on chromosome arm 5DS from different wheat genomes

Molecular Biology Reports - Stripe rust and leaf rust are among the most devastating diseases of wheat, limiting its production globally. Wheat wild relatives harbour genetic diversity for new...     

Mapping of flag smut resistance in common wheat

Flag smut, caused by Urocystis agropyri, has been a problem in wheat production, but its incidence has declined with the use of resistant varieties and seed dressing. Diamondbird, an Australian wheat cultivar that carries high levels of resistance to flag smut, was crossed with susceptible Chinese landrace TH3929 and a doubled haploid (DH) population was developed. A linkage map comprising 386 markers was used for detection of genomic regions controlling flag smut resistance. Composite interval mapping identified five quantitative trait loci (QTL) with significant effects for flag smut resistance. QTL QFs.sun-3AL, QFs.sun-6AS, QFs.sun-1BL and QFs.sun-5BS were contributed by Diamondbird. Although TH3929 was susceptible, it contributed a minor QTL QFs.sun-3AS. QTL QFs.sun-3AL and QFs.sun-6AS were detected in both seasons and each explained more than 17 % of the variation in flag smut response. Other QTL QFs.sun-3AS, QFs.sun-1BL and QFs.sun-5BS explained 5–10 % of the phenotypic variation. DH lines that showed low flag smut levels carried combinations of three or more QTL. This is the first report on chromosomal location of flag smut resistance in a modern common wheat cultivar.     

N-linked oligosaccharides of cobra venom factor contain novel alpha(1-3)galactosylated Le(x) structures

Cobra venom factor (CVF), a nontoxic, complement-activating glycoprotein in cobra venom, is a functional analog of mammalian complement component C3b. The carbohydrate moiety of CVF consists exclusively of N-linked oligosaccharides with terminal alpha1-3-linked galactosyl residues, which are antigenic in human. CVF has potential for several medical applications, including targeted cell killing and complement depletion. Here, we report a detailed structural analysis of the oligosaccharides of CVF. The structures of the oligosaccharides were determined by lectin affinity chromatography, antibody affinity blotting, compositional and methylation analyses, and high-resolution (1)H-NMR spectroscopy. Approximately 80% of the oligosaccharides are diantennary complex-type, approximately 12% are tri- and tetra-antennary complex-type, and approximately 8% are oligomannose type structures. The majority of the complex-type oligosaccharides terminate in Galalpha1-3Galbeta1-4(Fucalpha1-3)GlcNAcbeta1, a unique carbohydrate structural feature abundantly present in the glycoproteins of cobra venom.     

Multiple mechanisms compensate to enhance tumor-protective CD8(+) T cell response in the long-term despite poor CD8(+) T cell priming initially: comparison between an acute versus a chronic intracellular bacterium expressing a model antigen

We evaluated CD8(+) T cell responses against the dominant CTL epitope, OVA(257-264), expressed by an acute (Listeria monocytogenes (LM) OVA) vs a chronic pathogen (Mycobacterium bovis bacillus Calmette-Guérin (BCG) OVA) to reveal the influence on CD8(+) T cell memory and consequent protection against a challenge with OVA-expressing tumor cells. Infection with lower doses of both pathogens resulted in stronger bacterial growth but weaker T cell memory indicating that memory correlates with pathogen dose but not with bacterial expansion. The CD8(+) T cell response induced by LM-OVA was helper T cell-independent and was characterized by a rapid effector response followed by a rapid, but massive, attrition. In contrast, BCG-OVA induced a delayed and weak response that was compensated for by a longer effector phase and reduced attrition. This response was partly dependent on CD4(+) T cells. CD8(+) T cell response induced by BCG-OVA, but not LM-OVA, was highly dependent on pathogen persistence to compensate for the weak initial CD8(+) T cell priming. Despite a stronger initial T cell response with LM-OVA, BCG-OVA provided more effective tumor (B16OVA) control at both local and distal sites due to the induction of a persistently activated acquired, and a more potent innate, immunity.     

A new polymorphism in the type II deiodinase gene is associated with circulating thyroid hormone parameters

Type II deiodinase (D2) is important in the regulation of local thyroid hormone bioactivity in certain tissues. D2 in skeletal muscle may also play a role in serum triiodothyronine (T(3)) production. In this study, we identified a polymorphism in the 5'-UTR of the D2 gene (D2-ORFa-Gly3Asp). We investigated the association of D2-ORFa-Gly3Asp, and of the previously identified D2-Thr92Ala polymorphism, with serum iodothyronine levels. D2-ORFa-Gly3Asp was identified by sequencing the 5'-UTR of 15 randomly selected individuals. Genotypes for D2-ORFa-Gly3Asp were determined in 156 healthy blood donors (age 46.3 +/- 12.2 yr) and 349 ambulant elderly men (age 77.7 +/- 3.5 yr) and related to serum iodothyronine and TSH levels. D2-ORFa-Asp(3) had an allele frequency of 33.9% in blood bank donors and was associated with serum thyroxine (T(4); Gly/Gly vs. Gly/Asp vs. Asp/Asp = 7.06 +/- 0.14 vs. 6.74 +/- 0.15 vs. 6.29 +/- 0.27 microg/dl, P = 0.01), free T(4) (1.22 +/- 0.02 vs. 1.16 +/- 0.02 vs. 1.06 +/- 0.04 ng/dl, P = 0.001), reverse T(3) (P = 0.01), and T(3)/T(4) ratio (P = 0.002) in a dose-dependent manner, but not with serum T(3) (P = 0.59). In elderly men, D2-ORFa-Asp(3) had a similar frequency but was not associated with serum iodothyronine levels. This new polymorphism in the 5'-UTR of D2 is associated with iodothyronine levels in blood donors but not in elderly men. We hypothesize that this might be explained by the decline in skeletal muscle size during aging, resulting in a relative decrease in the contribution of D2 to serum T(3) production.     

Stark effect measurements on monomers and trimers of reconstituted light-harvesting complex II of plants

The electric-field induced absorption changes (Stark effect) of reconstituted light-harvesting complex II (LHCII) in different oligomerisation states-monomers and trimers-with different xanthophyll content have been probed at 77 K. The Stark spectra of the reconstituted control samples, containing the xanthophylls lutein and neoxanthin, are very similar to previously reported spectra of native LHCII. Reconstituted LHCII, containing lutein but no neoxanthin, shows a similar electrooptical response in the Chl a region, but the Stark signal of Chl b around 650 nm amounts to at most approximately 25% of that of the control samples. We conclude that neoxanthin strongly modifies the electronic states of the nearby Chl b molecules causing a large electrooptical response at 650 nm stemming from one or more Chls b in the control samples. Ambiguities about the assignment of several bands in the Soret region [Biochim. Biophys. Acta 1605 (2003) 83] are resolved and the striking difference in electric field response between the two lutein molecules is confirmed. The Stark effect in the carotenoid spectral region in both control and neoxanthin-deficient samples is almost identical, showing that the neoxanthin Stark signal is small and much less intense than the lutein Stark signal.