Confirmation of linkage of prostate cancer aggressiveness with chromosome 19q

Regions on chromosomes 7 and 19 were recently reported to contain susceptibility loci that regulate tumor aggressiveness of prostate cancer. To confirm these findings, we analyzed genome scan data from 161 pedigrees affected with prostate cancer. Using the Gleason score as a quantitative measure of tumor aggressiveness, we regressed the squared trait difference, as well as the mean-corrected cross product, on the estimated proportion of alleles shared identical-by-descent at each marker position. Our results confirm the previous linkage results for chromosome 19q (D19S902, P<.00001). In addition, we report suggestive evidence for linkage on chromosome 4 (D4S403, P=.00012). The results of previous findings, together with our results, provide strong evidence that chromosome 19 harbors a gene for tumor aggressiveness.     

The diageotropica mutation alters auxin induction of a subset of the Aux/IAA gene family in tomato

The diageotropica (dgt) mutation has been proposed to affect either auxin perception or responsiveness in tomato plants. It has previously been demonstrated that the expression of one member of the Aux/IAA family of auxin-regulated genes is reduced in dgt plants. Here, we report the cloning of ten new members of the tomato Aux/IAA family by PCR amplification based on conserved protein domains. All of the gene family members except one (LeIAA7) are expressed in etiolated tomato seedlings, although they demonstrate tissue specificity (e.g. increased expression in hypocotyls vs. roots) within the seedling. The wild-type auxin-response characteristics of the expression of these tomato LeIAA genes are similar to those previously described for Aux/IAA family members in Arabidopsis. In dgt seedlings, auxin stimulation of gene expression was reduced in only a subset of LeIAA genes (LeIAA5, 8, 10, and 11), with the greatest reduction associated with those genes with the strongest wild-type response to auxin. The remaining LeIAA genes tested exhibited essentially the same induction levels in response to the hormone in both dgt and wild-type hypocotyls. These results confirm that dgt plants can perceive auxin and suggest that a specific step in early auxin signal transduction is disrupted by the dgt mutation.     

The effect of dietary laminarin and fucoidan in the diet of the weanling piglet on performance, selected faecal microbial populations and volatile fatty acid concentrations

A 2 × 2 factorial experiment (n = 12 replicates per treatment, 4 pigs per replicate) was performed to investigate the effects of seaweed extracts, laminarin (derived ß-glucans) and fucoidan (sulphated polysaccharides), independently or in combination on post-weaning piglet performance and selected microbial populations. At weaning, the piglets (24 days of age, 6.4 kg live weight) were assigned to one of the four dietary treatments: (T1) basal diet, (T2) basal diet with 300 p.p.m. laminarin, (T3) basal diet with 240 p.p.m. fucoidan, (T4) basal diet with 300 p.p.m. laminarin and 240 p.p.m. fucoidan. Pigs offered diets supplemented with laminarin had an increased daily gain (P < 0.01), and gain-to-feed ratio (P < 0.05) compared to pigs offered diets without laminarin supplementation during the experimental period (days 0 to 21). Pigs offered laminarin-supplemented diets had an increased faecal dry matter and reduced diarrhoea (P < 0.05) during the critical 7 to 14 day period. Pigs offered diets containing laminarin had reduced faecal Escherichia coli populations. There was a significant interaction (P < 0.01) on faecal Lactobacilli populations between laminarin and fucoidan. Pigs offered the fucoidan diet had an increased Lactobacilli population compared to pigs offered the basal diet. However, there was no effect of fucoidan on faecal Lactobacilli populations when laminarin was added. Overall, the reduction in E. coli population and the increase in daily gain suggest that laminarin may provide a dietary means to improve gut health after weaning.     

Investigations of a prion infectivity assay to evaluate methods of decontamination

Prions are unique infectious agents which have been shown to be transmitted iatrogenically through contaminated surfaces. Surface contamination is a concern on reusable medical devices and various industrial surfaces, but there is currently no standard, accepted model to evaluate surface prion decontamination. In this report, a set of both in vitro and in vivo methods were investigated based on the contamination of surface through artificial exposure to infected brain. An in vitro surface contamination protocol was developed with subsequent biochemical detection of the prion protein (PrPres). In parallel, the in vivo investigations included the contamination of different types of surface materials (stainless steel or plastic wires) with different prion strains (scrapie strain adapted to hamsters 263K or bovine spongiform encephalopathy strain adapted to mouse 6PB1). The in vivo models with various prion strains and brain homogenate dilutions reproducibly transmitted the disease and a relationship was established between the infectivity titre, the transmission rate and the incubation period. Moreover, the in vivo models were studied for their ability to demonstrate the efficacy of heat and chemical-based decontamination methods, with similar results. The in vivo scrapie method described is proposed as a standard to evaluate existing and developing prion decontamination technologies.     

Relationship between mycobacteria and amoebae: ecological and epidemiological concerns

Since the discovery that Legionella pneumophila can survive and grow within free-living amoebae, there has been an increasing number of microbial species shown to have similar relationships. These include many bacterial species, fungi, other protozoa (e.g. Cryptosporidium) and viruses. Among bacteria, mycobacteria are of particular importance because of their role in human and animal infections. This review will consider the progress made in understanding the relationships between mycobacteria and amoebae, and their consequences in terms of ecology and epidemiology.     

Addressing childhood overweight through schools

Rates of childhood obesity in have reached alarming proportions in many countries. Sixteen percent of school-aged children and adolescents in the U.S. are overweight. Legislation implemented in 2004 in the U.S. requires local education agencies (LEAs) that sponsor school meal programs to establish local wellness policies to address childhood obesity. Project PA, a collaboration between a state agency and a university providing school-based interventions focuses on the school environment and policy changes. Interventions have targeted foodservice personnel, administrators, teachers, parents and students. In two recent projects schools assessed their school nutrition environments, developed nutrition policies, and implemented strategies to encourage healthier food selections. Schools identified weaknesses in the areas of marketing and communication of policies. Media attention on the childhood obesity facilitated policy changes. Time and cost were identified as barriers to policy development and there were concerns about weak enforcement of policies. These themes are discussed.