Silencing of β-1,3-glucanase genes in tobacco correlates with an increased abundance of RNA degradation intermediates

Post-transcriptional gene silencing of beta-1,3 glucanase genes in the transgenic tobacco line T17 is characterised by an increased turnover and, as a consequence, reduced levels of gn1 transgene and endogenous beta-1,3 glucanase mRNAs, Here, additional gn1 RNAs, both larger and smaller than the full-length messenger, are shown to accumulate in silenced plants of the transgenic tobacco line T17, The longer-than-full-length gn1 RNAs are the result of cryptic processing of the gn1 messenger, The small gnl RNAs in silenced plants correspond to distal and proximal parts of the mature gn1 messenger. The proximal RNA products are intact at their 5' extremity, but terminate at different positions at the 3'-end. The distal RNA products contain a poly(A) tail and are truncated to various positions at the 5'-end, These observations indicate that degradation of the mature gnl transcript does not start at the 5'- or 3'-end, but rather are consistent with degradation of the gnl transcript starting with an endonucleolytic cleavage followed by internal exonuclease digestion. Importantly, the truncated products are more abundant in silenced plants than in expressing plants, This suggests, together with the previously reported silencing-related increased gnl mRNA turnover and the similar rates of gnl transcription in silenced and expressing T17 plants, that the predominant decay route for the gnl transcripts differs between silenced and expressing conditions

Demography and disorders of German Shepherd Dogs under primary veterinarycare in the UK

The German Shepherd Dog (GSD) has been widely used for a variety of working roles. However, concerns for the health and welfare of the GSD have been widely aired and there is evidence that breed numbers are now in decline in the UK. Accurate demographic and disorder data could assist with breeding and clinical prioritisation. The VetCompassTM Programme collects clinical data on dogs under primary veterinary care in the UK. This study included all VetCompassTM dogs under veterinary care during 2013. Demographic, mortality and clinical diagnosis data on GSDs were extracted and reported

Dog Bites in Humans and Estimating Human Rabies Mortality in Rabies Endemic Areas of Bhutan

Dog bites in humans are a public health problem worldwide. We conducted a hospital based questionnaire survey and described the incidence and risk factors for human dog bites in Bhutan. We also estimated the human death rate attributable to rabies in two rabies endemic areas of south Bhutan. Our study shows that dog bites incidents in humans are common in the survey areas. There were significant gender and age differences in bite incidents; males and the children are affected the most. The majority of the victims were bitten by stray dogs, increasing the risk of rabies infection if not treated in time. Our decision tree model predicted 2.23 (95% CI: 1.20–3.59) human deaths from rabies/year, equivalent to an annual incidence of 4.67 (95% CI: 2.53–7.53) deaths/100,000 in the two rabies endemic areas of south Bhutan. In the absence of post exposure prophylaxis, the model predicted 19.24 (95% CI: 13.69–25.14) deaths/year in these two areas. The public should be encouraged to visit hospitals for post exposure prophylaxis following dog bite injury in south Bhutan

Post-transcriptional β-1,3-glucanase gene silencing involves increased transcript turnover that is translation-independent

In tobacco line T17, basic beta-1,3-glucanases are silenced when a beta-1,3-glucanase (gn1) transgene of Nicotiana plumbaginifolia is present in a homozygous condition. Cosuppression of endogenous and transgenic basic beta-1,3-glucanases occurs via a post transcriptional process. This study shows that silencing correlates with a reduced stability of the transcripts encoded by gn1 and the co-suppressed endogenous glucanase genes. The observed decreases in mRNA stability at least partially explain the reductions in mRNA level. Furthermore, the results show that the enhanced, silencing-related turnover of gn1 mRNA does not require continued protein synthesis. The implications of these findings for the mechanism of gene silencing are discussed

Sequences throughout the basic β-1,3-glucanase mRNA coding region are targets for homology dependent post-transcriptional gene silencing

In the transgenic tobacco line T17, plants homozygous for the gn1 transgene display developmentally regulated post-transcriptional silencing of basic beta-1,3-glucanase genes. Previously, it has been shown that silencing involves a markedly increased turnover of silencing-target glucanase mRNAs. Using a two-component viral reporter system facilitated a comparison, in a quantitative manner, of the relative silencing efficiencies of various sequences derived from the gn1 transgene. The results show that target sites for the silencing mechanism are present throughout the coding region of the gn1 nnRNA. Similar-sized coding region sequences along the entire gn1 mRNA display a similar susceptibility to the silencing mechanism. The susceptibility to silencing increases as the coding region elements increase in size. Relative to internal sequences, the 5' and 3' terminal regions of the gn1 mRNA are inefficient targets for the silencing machinery. Importantly, sequences of the gn? transgene that are not part of the mature gn1 mRNA are not recognized by the silencing machinery when expressed in chimeric viral RNAs. These results show that the glucanase silencing mechanism in T17 plants is primarily directed against gn1 mRNA-internal sequences and that terminal sequences of the gn1 mRNA are relatively unaffected by the silencing mechanism

Functional characteristics of corticolous lichens in the understory of a tropical lowland rain forest

In tropical lowland forests, corticolous crustose green algal lichens are abundant and highly diverse. This may be related to adaptation to prevailing microenvironmental conditions including, for example, high precipitation and low light intensities. In the understory of a tropical lowland rain forest in French Guiana, we studied the morphology of crustose green algal lichens and measured gas exchange and chlorophyll a fluorescence. We found that (i) periods of thallus suprasaturation with water were reduced by the presence of water-repelling surface structures of mycobiont hyphae at the thallus surface and the medulla; (ii) photosynthesis was adapted to the low light intensities present in the understory; and (iii) photosynthesis was rapidly activated in fluctuating light. The combination of these three mechanisms enables corticolous lichens to implement specific morphological and physiological strategies, which may favour growth in the limiting understory habitat of tropical lowland rain forests