A sodium transporter (HKT7) is a candidate for Nax1, a gene for salt tolerance in durum wheat

Durum wheat (Triticum turgidum subsp. durum) is more salt sensitive than bread wheat (Triticum aestivum). A novel source of Na(+) exclusion conferring salt tolerance to durum wheat is present in the durum wheat Line 149 derived from Triticum monococcum C68-101, and a quantitative trait locus contributing to low Na(+) concentration in leaf blades, Nax1, mapped to chromosome 2AL. In this study, we used the rice (Oryza sativa) genome sequence and data from the wheat expressed sequence tag deletion bin mapping project to identify markers and construct a high-resolution map of the Nax1 region. Genes on wheat chromosome 2AL and rice chromosome 4L had good overall colinearity, but there was an inversion of a chromosomal segment that includes the Nax1 locus. Two putative sodium transporter genes (TmHKT7) related to OsHKT7 were mapped to chromosome 2AL. One TmHKT7 member (TmHKT7-A1) was polymorphic between the salt-tolerant and -sensitive lines, and cosegregated with Nax1 in the high-resolution mapping family. The other TmHKT7 member (TmHKT7-A2) was located within the same bacterial artificial chromosome contig of approximately 145 kb as TmHKT7-A1. TmHKT7-A1 and -A2 showed 83% amino acid identity. TmHKT7-A2, but not TmHKT7-A1, was expressed in roots and leaf sheaths of the salt-tolerant durum wheat Line 149. The expression pattern of TmHKT7-A2 was consistent with the physiological role of Nax1 in reducing Na(+) concentration in leaf blades by retaining Na(+) in the sheaths. TmHKT7-A2 could control Na(+) unloading from xylem in roots and sheaths.     

Contrasting patterns in the small-scale heterogeneity of human helminth infections in urban and rural environments in Brazil

Marked heterogeneity exists in the patterns of parasitic infection between individuals, households and communities. Analysis of parasite distributions within populations is complicated by the fact that parasite distributions are highly aggregated and few studies have explicitly incorporated this distribution when investigating small-scale spatial heterogeneities. This study aimed to quantify the small-scale (within- and between-household) heterogeneity of helminth infection in an area of Minas Gerais State, Brazil, with rural and urban sectors. Parasitological data from a cross-sectional survey of 1,249 individuals aged 0-86 years from 242 households were analysed. Within-household clustering of infection was assessed using random effect logistic regression models and between-household spatial heterogeneity was assessed using a Bayesian negative binomial spatial model. The overall prevalence of hookworm (Necator americanus) was 66.9%, the prevalence of Schistosoma mansoni was 44.9% and the prevalence of Ascaris lumbricoides was 48.8%. Statistical analysis indicated significant (within) household and (between household) spatial clustering of hookworm in both rural and urban areas and of S. mansoni in rural areas. There was no evidence of either household or spatial clustering of S. mansoni in urban areas. The spatial correlation of S. mansoni was estimated to reduce by half over a distance of 700 m in the rural area. Rural hookworm had a much smaller half-distance (28 m) and urban hookworm showed an even smaller half-distance (12 m). We suggest that such species-specific differences in patterns of infection by environment are primarily due to variation in exposure and parasite life cycle, although host genetic factors cannot be ruled out.     

Fish Chromatophores as Biomarkers of Arsenic Exposure

We examined the possibility of using fish chromatophores as markers of arsenic exposure. Our results not only favor their suitability but also suggest an adaptive mechanism in fish against arsenic toxicity. We also compare results between arsenic accumulation, melanophore index and neurosecretory cells. Chromatophores can be used as a quick and reliable biomarker of aquatic metal pollution.     

Use of zinc chloride as alternative stimulant for in vitro study of nitric oxide production pathway in avian splenocyte culture

Nitric Oxide (NO) plays an important role for regulation of cellular and vascular response of inflammation and initiates killing mechanism in the host-defense reactions. NO production is regulated through inducible nitric oxide synthase (iNOS) pathway in response to infections and injurious agents besides pro-inflammatory cytokines secreted by the host. Evaluation of NO pathway is one of the major targets which can evaluate various immunomodulators for their therapeutic interaction on innate immune system. Lipopolysaccharide (LPS) and concavalin A (ConA) are used as standard mitogen for peripheral blood mononuclear cells and splenocyte of mammalian and avian cell culture. During the present investigation ZnCl₂ has been explored as standard mitogen and result was comparable with standard mitogen. The result has been evaluated on the basis of relative mRNA expression of iNOS and interferon gamma and nitrite assay. Observation indicated significantly higher expression of both biomolecules in comparison to control, LPS, ConA treated group. This study indicated that, ZnCl₂ can also be used as standard stimulant for molecular mining of innate immunity.     

Synthesis of p-nitrophenyl 2-O-α- and -β-l-fucopyranosyl-β-d-fucopyranoside

Reaction of 2,3,4-tri-O-acetyl-α-l-fucopyranosyl bromide with p-nitrophenyl 3,4-O-isopropylidene-β-d-fucopyranoside in the presence of mercuric cyanide in acetonitrile, followed by removal of the isopropylidene group under mild conditions, gave a mixture of p-nitrophenyl 2-O-(2,3,4-tri-O-acetyl-α- and -β-l-fucopyranosyl)-β-d-fucopyranoside. These compounds were conveniently separated by preparative, thin-layer chromatography, and, on deacetylation, gave the title disaccharides, whose structures were established by ¹H- and ¹³C-n.m.r. spectroscopy.