DNA origami signposts for identifying proteins on cell membranes by electron cryotomography

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Indoxyl-tetranitro blue tetrazolium method for detection of alkaline phosphatase in immunohistochemistry

A sensitive method for detection of alkaline phosphatase in immunohistochemistry, using lymphoid cells, has been optimized. The conditions for staining are 0.23 mM 5-bromo-4-chloro-indoxyl phosphate, 0.55 mM tetranitro blue tetrazolium, 2.0 mM levamisole, 5.0 mM sodium azide, 10.0 mM magnesium chloride, and 0.15 mM 1-methoxyphenazine methosulfate dissolved in 100 mM Tris-HCl buffer, pH 9.5.     

Prevalence of Cryptosporidium species in recreational versus non-recreational water sources

Cryptosporidiosis, caused by the protozoan parasite Cryptosporidium, represents the major public health concern of water utilities in developed nations due to its small size, resistance to disinfection and ability to be shed in large numbers in faeces. In Australia, recreational access is not allowed on direct supply sources, however, in Western Australia, limited recreational access to drinking water catchments has been allowed, although only in the outer catchment. Recreational activities within 2 km of the drinking water body is prohibited. The present study compared the amount, prevalence and species of Cryptosporidium in recreational versus non-recreational water catchments in the south west of Western Australia (WA). Recreational water catchments, which allowed swimming and camping had a higher prevalence of Cryptosporidium and the majority of samples were the human-associated C. hominis. Non-recreational catchments had a lower prevalence and all the samples genotyped were C. parvum. Risk analysis identified increasing population as strongly correlated with an increase in the prevalence of Cryptosporidium in recreational catchments. This suggests that recreational access to drinking water catchments is a serious public health risk and government policy limiting activities to the outer catchment should be supported.     

An E mu-v-abl transgene elicits plasmacytomas in concert with an activated myc gene.

To clarify how the v-abl oncogene of Abelson murine leukemia virus contributes to lymphoid tumorigenesis, we introduced the gene linked to an immunoglobulin heavy chain enhancer (E mu) into the mouse germline. Although lymphoid development was not detectably affected in young E mu-v-abl mice, three transgenic lines shared a high predisposition to develop clonal plasmacytomas that secreted IgA or IgG. The unexpected absence of pre-B lymphomas suggests that Abelson virus generates such tumors by infecting an early lymphoid progenitor cell that has not yet activated the heavy chain enhancer. Most plasmacytomas bore a rearranged c-myc gene, apparently as a result of spontaneous translocation to the Igh locus. Moreover, progeny of a cross with analogous E mu-myc mice rapidly developed oligoclonal plasmacytomas. Thus, the collusion of v-abl with c-myc is stage specific, efficiently transforming plasma cells but not pre-B cells or B cells.     

Genetic variation at the growth hormone (GH1) and growth hormone receptor (GHR) loci as a risk factor for hypertension and stroke

An increased prevalence of both hypertension and cerebrovascular stroke is apparent in growth hormone (GH) deficiency whilst hypertension is a frequent complication in acromegaly. This has suggested a possible link between GH, stature and arterial function. Since the risk of both hypertension and stroke also appears to be inversely correlated with adult height, we have instigated an exploratory study to assess whether inter-individual variation in the genes encoding human growth hormone (GH1) and the GH receptor (GHR) might be associated with an increased risk of hypertension and stroke. GH1 promoter haplotypes were found to differ significantly not only between hypertensive patients (n=111) and controls (n=121) but also between stroke patients (n=155) and controls (n=158). Intriguingly, the association between GH1 promoter haplotype and risk of hypertension was much greater in females than in males. An inverse correlation between height and central systolic blood pressure was apparent in both hypertensive patients and normal controls but was much stronger in individuals carrying at least one GH1 promoter risk haplotype. The GH1 genotype therefore constitutes a risk factor for hypertension that interacts with stature. A strong association was found between the presence of at least one GH1 risk haplotype and a family history of stroke at an early age (odds ratio: 9.07, 95% confidence interval: 1.14–72.22). Three novel GH variants (Arg16His, Phe176Cys, Cys189Arg) were identified during the course of this study. Although two exhibited markedly reduced biological activity in vitro, their clinical significance remains unclear. No association was found between GHR genotype and either hypertension or stroke, nor was any interaction noted between GHR and GH1 genotypes in terms of a disease association. However, an association between GHRd3 genotype and hypertension was observed among stroke patients, particularly females. Elevated HDL was found to be a risk factor for hypertension in individuals lacking a copy of the GHRd3 allele. Weak associations with GHR genotype were also noted for peripheral systolic and diastolic blood pressure in hypertensive patients. Although the underlying mechanisms are still unclear, our findings are consistent with a complex relationship between height, hypertension, GH1 promoter haplotype, GHR polymorphism and the risk of stroke.     

Imputation of missing genotypes: an empirical evaluation of IMPUTE

Background

Polymorphism in genes of regulating enzymes, transporters and receptors of the neurotransmitters of the central nervous system have been associated with altered behaviour, and single nucleotide polymorphisms (SNPs) represent the most frequent type of genetic variation. The serotonin and dopamine signalling systems have a central influence on different behavioural phenotypes, both of invertebrates and vertebrates, and this study was undertaken in order to explore genetic variation that may be associated with variation in behaviour.

Results

Single nucleotide polymorphisms in canine genes related to behaviour were identified by individually sequencing eight dogs (Canis familiaris) of different breeds. Eighteen genes from the dopamine and the serotonin systems were screened, revealing 34 SNPs distributed in 14 of the 18 selected genes. A total of 24,895 bp coding sequence was sequenced yielding an average frequency of one SNP per 732 bp (1/732). A total of 11 non-synonymous SNPs (nsSNPs), which may be involved in alteration of protein function, were detected. Of these 11 nsSNPs, six resulted in a substitution of amino acid residue with concomitant change in structural parameters.

Conclusion

We have identified a number of coding SNPs in behaviour-related genes, several of which change the amino acids of the proteins. Some of the canine SNPs exist in codons that are evolutionary conserved between five compared species, and predictions indicate that they may have a functional effect on the protein. The reported coding SNP frequency of the studied genes falls within the range of SNP frequencies reported earlier in the dog and other mammalian species. Novel SNPs are presented and the results show a significant genetic variation in expressed sequences in this group of genes. The results can contribute to an improved understanding of the genetics of behaviour.