A 50 kDa maize gamma-zein has marked cross-reactivity with the almond major protein

Cross-reactivity of antibodies against almond major protein (AMP, a legumin), the major almond allergen, with cereal proteins may cause problems in detecting almond contaminants in cereal products when antibody-based assays are used. Rabbit polyclonal IgG antiserum produced against AMP was used to test cross-reactivity with protein extracts from maize, a cereal commonly found in breakfast and snack foods. Gradient SDS-PAGE followed by Western blotting was performed, and two cross-reactive proteins were detected by chemiluminescence. A fraction of maize proteins purified by elution from an IgG anti-AMP affinity column followed by electrophoreseis and immunoblotting showed a high degree of cross-reactivity with a minor 50 kDa protein of maize, as well as low cross-reactivity with the 27 kDa gamma-zein. The 50 kDa cross-reactive protein was identified as the 50 kDa gamma-zein by immunoreaction with anti-50 kDa gamma-zein antiserum. Notably, the 50 kDa maize gamma-zein also reacted with IgE from pooled human sera from patients with self-reported severe almond allergies. The high immunoreactivity of the 50 kDa gamma-zein should be considered in maize quality improvement programs, and such notable cross-reactivity is of relevance in the design of antibody-based assays for almond allergen detection.     

Metabolism of glycitein (7,4'-dihydroxy-6-methoxy-isoflavone) by human gut microflora

Gut microbial disappearance and metabolism of the soy isoflavone glycitein, 7,4'-dihydroxy-6-methoxyisoflavone, were investigated by incubating glycitein anaerobically with feces from 12 human subjects. The subjects' ages ranged from 24 to 53 years with a body mass index (BMI) of 20.9-25.8 kg/m(2) (mean BMI = 24.0 +/- 1.1 kg/m(2)). Glycitein disappearance followed an apparent first-order rate loss. Fecal glycitein disappearance rates for the subjects segregated into three different groups described as high (k = 0.67 +/- 0.14/h), moderate (k = 0.34 +/- 0.04/h), and low (k = 0.15 +/- 0.07/h) glycitein degraders (p < 0.0001). There was no dose effect on the disappearance rates for each subject from 10 to 250 microM glycitein (average k = 0.32 +/- 0.03/h, p > 0.05). Four putative glycitein metabolites, characterized by liquid chromatography-mass spectrometry (electrospray ionization using positive ionization mode), were dihydroglycitein, dihydro-6,7,4'-trihydroxyisoflavone, and 5'-O-methyl-O-desmethylangolensin. Two subjects produced a metabolite tentatively identified as 6-O-methyl-equol, and one subject produced daidzein as an additional metabolite of glycitein. These results show that glycitein is metabolized by human gut microorganisms and may follow metabolic pathways similar to other soy isoflavones.     

Field assessment of dog as sentinel animal for plague in endemic foci of Madagascar

The epidemiology of Yersinia pestis, the causative agent of plague, involves vectors and reservoirs in its transmission cycle. The passive plague surveillance in Madagascar targets mainly rodent and fleas. However, carnivores are routinely surveyed as sentinels of local plague activity in some countries. The aim of this study is to assess the use of domestic dog (Canis familiaris) as sentinel animal for field surveillance of plague in a highly endemic area in Madagascar. Cross-sectional surveys of plague antibody prevalence in C. familiaris were conducted in endemic areas with contrasting histories of plague cases in humans, as well as a plague free area. Rodent capture was done in parallel to evaluate evidence for Y. pestis circulation in the primary reservoirs. In 2 sites, dogs were later re-sampled to examine evidence of seroconversion and antibody persistence. Biological samplings were performed between March 2008 and February 2009. Plague antibody detection was assessed using anti-F1 ELISA. Our study showed a significant difference in dog prevalence rates between plague-endemic and plague-free areas, with no seropositive dogs detected in the plague free area. No correlation was found between rodents and dog prevalence rates, with an absence of seropositive rodents in some area where plague circulation was indicated by seropositive dogs. This is consistent with high mortality rates in rodents following infection. Re-sampling dogs identified individuals seropositive on both occasions, indicating high rates of re-exposure and/or persistence of plague antibodies for at least 9 months. Seroconversion or seropositive juvenile dogs indicated recent local plague circulation. In Madagascar, dog surveillance for plague antibody could be useful to identify plague circulation in new areas or quiescent areas within endemic zones. Within active endemic areas, monitoring of dog populations for seroconversion (negative to positive) or seropositive juvenile dogs could be useful for identifying areas at greatest risk of human outbreaks.     

Leishmania RNA virus controls the severity of mucocutaneous leishmaniasis

Mucocutaneous leishmaniasis is caused by infections with intracellular parasites of the Leishmania Viannia subgenus, including Leishmania guyanensis. The pathology develops after parasite dissemination to nasopharyngeal tissues, where destructive metastatic lesions form with chronic inflammation. Currently, the mechanisms involved in lesion development are poorly understood. Here we show that metastasizing parasites have a high Leishmania RNA virus-1 (LRV1) burden that is recognized by the host Toll-like receptor 3 (TLR3) to induce proinflammatory cytokines and chemokines. Paradoxically, these TLR3-mediated immune responses rendered mice more susceptible to infection, and the animals developed an increased footpad swelling and parasitemia. Thus, LRV1 in the metastasizing parasites subverted the host immune response to Leishmania and promoted parasite persistence.     

Effect of increasing the time between slurry application and first rainfall event on phosphorus concentrations in runoff

Minimizing slurry phosphorus (P) losses in runoff requires careful management in the context of both soil P surpluses and changing patterns in rainfall. Increasing the time interval between slurry application and the first rainstorm event is known to reduce P loss in runoff although the risk period for elevated P concentrations in runoff can extend for weeks. This study investigated the impact of increasing the time interval between slurry application and first rainstorm event on P concentrations in runoff. Simulated rainfall (40 mm h⁻¹) was applied at 2, 4, 10, 18, 30 and 49 days after dairy slurry was surface-applied to a grassland sward in Ireland. Increasing time to runoff resulted in a decrease in dissolved reactive P concentrations from 5.0 to 1.0 mg P L⁻¹ and a P signal in runoff for 18 days. Beyond 18 days, elevated P concentrations were observed in runoff collected from natural rainfall that preceded the day 49 rainstorm event. A published surface phosphorus and runoff model (SurPhos) was used to understand the slurry P dynamics controlling P interactions with runoff. Dissolved reactive P in runoff was predicted with accuracy by SurPhos, R² = .89. The SurPhos model implied that slurry P mineralization occurred during the experimental period that resulted in a small spike in P concentrations beyond the defined risk period. This study shows that the experimental data have the potential to be extrapolated to different weather scenarios using SurPhos and could test when and where slurry P could be most safely spread.     

Molecular cloning and genetic polymorphism of Babesia capreoli gene Bcp37/41, an ortholog of Babesia divergens merozoite surface antigen Bd37

Babesia divergens and Babesia capreoli are closely related species with distinct host ranges, a zoonotic feature being described only for B. divergens. The two species are 99.8% similar in the 18S rDNA gene sequence and indistinguishable by morphological or serological means, leading to confusion as to their species status. The phylogenetic relatedness between the two species, and the frequent involvement of surface components in serological cross-reactions led us to postulate that an ortholog of Bd37, the merozoite surface antigen described for B. divergens, could also exist in B. capreoli. We were able to amplify a single partial PCR product from B. capreoli genomic DNA using primers specific for the B. divergens merozoite surface protein coding gene Bd37, and sequencing confirmed the presence of a Bd37 ortholog in B. capreoli, named Bcp37/41. The full sequences of the Bcp37/41 genes and their intron-exon structures were obtained for two cloned lines of B. capreoli. They suggest functional homologies between Bd37 and Bcp37/41 such as their surface localization, their role in immune escape mechanism and in the initial non-specific attachment to the erythrocyte. Restriction fragment length polymorphism (RFLP) analysis of the amplicons and partial sequencing revealed an extreme polymorphism within B. capreoli, greater than the one observed for its ortholog Bd37. Such a marker could thus be useful in epidemiological as well as phylogenetic studies.