Selecting an appropriate method for expressing S locus F-box-S2 recombinant protein.

A single locus (S locus) including at least two linked genes (female and male determinants) genetically controls the gametophytic self-incompatibility (GSI) in apple, which has evolved to avoid self-fertilization. There has been extensive work done on the female determinant of self-incompatibility, which has led to the determination of the tertiary structure of S-RNase. However, the tertiary structure of male determinant (S locus F-box, SLF/SFB) remains unresolved, which could mainly be due to difficulties associated with its expression in the recombinant expression systems. In addressing this, we have evaluated several in vivo (prokaryotic and eukaryotic) and in vitro expression systems for their efficiency in the expression of apple SLF2. The most successful expression of SLF2 (1 mg/ml) was achieved in E. coli using the synthesized gene in a high salt culture and applying heat shock before induction of culture. We therefore present an approach for the efficient expression of S locus F-box recombinant proteins for future functional and structural studies.

A simple, high-throughput modeling approach reveals insights into the mechanism of gametophytic self-incompatibility.

Specificity in the GSI response results from the S-haplotype-specific molecular interaction of S-locus F-box (SLF/SFB) and SRNase proteins in the self-incompatibility locus (S-locus). The answer to the question of how these two components of the S-locus (SRNase and SLF/SFB) interact has been gathered from several models. Since there is not enough evidence as to which one is the definitive model, none of them can be ruled out. Despite the identification of interacting protein elements, the mechanism by which SLF/SFB and SRNase interact to differently trigger the self-incompatibility among families and subfamilies remain uncertain. The high-throughput modeling approach demonstrates structural visions into the possible existence of a Collaborative Non-Self Recognition model in apple. These findings postulate several prospects for future investigation providing useful information to guide the implementation of breeding strategies.

The Critical Role Of VP1 In Forming The Necessary Cavities For Receptor-mediated Entry Of FMDV To The Host Cell.

The antigenic inconsistency of the foot-and-mouth disease virus (FMDV) is very broad, such that a vaccine made from one isolate will not offer protection against infection with other isolates from the same serotype. Viral particles (VPs) or surface exposed capsid proteins, VP1-VP3, of FMDV determine both the antigenicity of the virus and its receptor-mediated entry into the host cell. Therefore, modifications of these structural proteins may alter the properties of the virus. Here we show putative cavities on the FMDV-SAT1 (FMDV Southern African Territories1) capsid as possible binding sites for the receptor-mediated viral entry into the host cell. We identified three possible cavities on the FMDV capsid surface, from which the largest one (C2) is shaped in the contact regions of VP1-VP3. Our results demonstrate the significance of VP1, in the formation of FMDV-SAT1 surface cavities, which is the main component in all the identified cavities. Our findings can have profound implications in the protein engineering of FMDV in the contact region of VP1-VP3 found to be embedded in several cavities. Such information is of great significance in the context of vaccine design, as it provides the ground for future improvement of synthetic vaccines to control FMD caused by FMDV-SAT1 serotypes.

Tropically adapted cattle of Africa: perspectives on potential role of copy number variations.

Africa is host to diverse and locally adapted cattle breeds that are expected to survive the harsh and extreme tropical environments associated with diseases and parasite infections, heat stress and episodes of feed and water scarcity. Genomic copy number variations (CNVs) are considered to be primary role players in cattle breed formation and adaptation where isolation and genetic drift together with subsequent mutations have created an enormous diversity of local populations. CNVs are modifications in DNA structure comprising deletions, duplications and insertions that are >1 kb in size. Despite attracting much attention, the frequency and pattern of bovine CNV events, especially in African cattle breeds, are for the most part largely unknown. Characterization of genetic variation in the indigenous cattle of Africa will be a vital step toward dissecting the molecular mechanisms underlying phenotypic variation and local adaptation. This review therefore aims to describe the current knowledge regarding bovine CNVs and the implications and potentials they encompass for dissecting genetic adaptation and the genotypic skeleton of tropical African cattle populations.

A Comprehensive Study of Molecular Evolution at the Self-Incompatibility Locus of Rosaceae.

The family Rosaceae includes a range of important fruit trees, most of which have the S-RNase-based self-incompatibility (SI). Several models have been developed to explain how pollen (SLF) and pistil (S-RNase) components of the S-locus interact. It was discovered in 2010 that additional SLF proteins are involved in pollen specificity, and a Collaborative Non-Self Recognition model has been proposed for SI in Solanaceae; however, the validity of such model remains to be elucidated for other species. The results of this study support the divergent evolution of the S-locus genes from two Rosaceae subfamilies, Prunoideae/Amygdaloideae and Maloideae, The difference identified in the selective pressures between the two lineages provides evidence for positive selection at specific sites in both the S-RNase and the SLF proteins. The evolutionary findings of this study support the role of multiple SLF proteins leading to a Collaborative Non-Self Recognition model for SI in the Maloideae. Furthermore, the identification of the sites responsible for SI specificity determination and the mapping of these sites onto the modelled tertiary structure of ancestor proteins provide useful information for rational functional redesign and protein engineering for the future engineering of new functional alleles providing increased diversity in the SI system in the Maloideae.

In vitro cytotoxic and pro-apoptotic effects of water extracts of Tulbaghia violacea leaves and bulbs.

ETHNOPHARMACOLOGICAL RELEVANCE: Infusions of Tulbaghia violacea (wild garlic) in water are used in traditional medicine in Southern Africa to treat numerous diseases, including cancer. Several studies have previously demonstrated the cytotoxic activities of extracts of T. violacea in cultured cancer cells. Their findings support the potential anti-cancer properties of this plant. However, these studies made use of organic solvent extraction methods, while the traditional use of the plant involves the preparation of infusions in water. MATERIALS AND METHODS: In the current study, we investigated the potential anti-cancer properties of infusions of T. violacea. We also performed a comparative study investigating the cytotoxic activities of T. violacea bulbs and leaves. A panel of four cancer cell lines (HepG2, MCF7, H157, and HT29) and one non-cancerous cell line (KMST6) was treated with the two extracts and the effects of the extracts on the growth of the cells were evaluated. We also investigated whether the growth inhibitory effects were associated with the induction of apoptosis and whether the mechanism of cell death is the result of oxidative stress and the activation of caspase-3. RESULT: We found that extracts of the leaves and not the bulbs have growth inhibitory effects and that this is the result of the induction of apoptosis, which is associated with the production of Reactive Oxygen Species (ROS) and the activation of caspase-3. The leaf extract demonstrated variable selective toxicity towards the cancer lines. Although the extract also induced cell death in the non-cancerous cell line (KMST6), we found that the levels of toxicity were lower in this cell line. CONCLUSION: this study confirms that infusions of T. violacea have potential anti-cancer activity and that this bioactivity is contained in the leaf extract. This study lends support to claims that this plant can be used to treat cancer.