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Abstract We have constructed an African cassava mosaic virus (ACMV) based gene-silencing vector as a reverse genetics tool for gene function analysis in cassava. The vector carrying a fragment from the Nicotiana tabacumsulfur gene (su), encoding one unit of the chloroplast enzyme magnesium chelatase, was used to induce the silencing of the cassava orthologous gene resulting in yellow–white spots characteristic of the inhibition of su expression. This result suggests that well developed sequence databases from model plants like Arabidopsis thaliana, Nicotiana benthamiana, N. tabacum, Lycopersicon esculentum and others could be used as a major source of information and sequences for functional genomics in cassava. Furthermore, a fragment of the cassava CYP79D2endogenous gene, sharing 89% homology with CYP79D1endogenous gene was inserted into the ACMV vector. The resultant vector was inducing the down regulation of the expression of these two genes which catalyze the first-dedicated step in the synthesis of linamarin, the major cyanogenic glycoside in cassava. At 21days post-inoculation (dpi), a 76% reduction of linamarin content was observed in silenced leaves. Using transgenic plants expressing antisense RNA of CYP79D1and CYP79D2, Siritunga and Sayre (2003) obtained several lines with a reduction level varying from 60% to 94%. This result provides the first example of direct comparison of the efficiency of a virus-induced gene silencing (VIGS) system and the transgenic approach for suppression of a biosynthetic pathway. The ACMV VIGS system will certainly be a complement and in some cases an alternative to the transgenic approach, for gene discovery and gene function analysis in cassava.

Focuses on the Scottish mountain hare. Coat-changing characteristic of the hare; Rarity of the black mountain hare; Number of black mountain hares shot in the Langwell area between 1900 and 1925; Description of mounted specimens in museums in the country.

Focuses on the wild goats in Strathdearn Valley, Scotland. Topographical and seasonal differences in giving birth to kids; Population growth of the goats in surrounding areas; Speculations on the origin of the goats.

This article offers guidelines for utilizing an Internet-based backup system. Internet backup was available to anyone with an Internet connection, but the market for that type of offsite storage still struggled. Internet backup, though not speedy, frees one from physical media altogether. It is secure against intruders and disasters alike, arguably more so than traditional backup methods, and it only requires attention when you first set it up, change its settings, or retrieve some back-up files. To back up the traditional way, first run either Microsoft's built-in backup software or a backup program you have installed. Choose which files or folders full of files you want to back up, and what CD, tape drive or other destination you want them backed up to. Make sure the destination is ready and click a button to proceed. To back up over the Internet, you will start by visiting a company's Web site and downloading its backup software. When finish, run the software, select which files or folders you want to back up, and click to proceed. There is no need to choose a destination.