'n Ondersoek na operasionele praktykvoerings en- bestuursriglyne vir stads- en streekbeplanners: Moontlike riglyne vir die privaat praktyk

Die Vryemark-ekonomie moedig die vestiging van nuwe ondememings aan asook die groei van bestaande ondernemings. Hierdie studie het van die standpunt uitgegaan dat talle persone graag ’n eie onderneming wil begin, maar nie werklik die nodige bestuursvaardigheid het nie. Die privaat praktyk kan die vergestalting van ’n wye ondememingstelsel vir die beplanner wees; dit is die vryheid van die individu om vir sy eie voordeel ’n onderneming van sy eie keuse te begin en te bedryf. Die stelsel van mededinging en handel, asook die aanmoediging om nuwe ondernemings te vestig, is tiperend van ’n verskeidenheid ondernemings waarin ook die beplanner i.t.v. geesdrif, inisiatief, vindingrykheid, kreatiwiteit en sy besondere kundigheid, uiting in ’n eie praktyk kan vind

Planning for the upgrading of informal settlements

Planning for the upgrading of informal settlements is still a relatively unknown field for planners in South Africa and it is certain to receive more attention in future. The role of the upgrading of informal settlements in providing low income housing will be discussed, as well as certain factors that play an important role in planning projects of this kind. A "strategy", involving certain alternative solutions available to the planner in the field, will then be put forward. Findings from a study done in Joe Slovo Square, Bloemfontein, will be used to illustrate the article

ANK, a Host Cytoplasmic Receptor for the Tobacco mosaic virus Cell-to-Cell Movement Protein, Facilitates Intercellular Transport through Plasmodesmata

Plasmodesma (PD) is a channel structure that spans the cell wall and provides symplastic connection between adjacent cells. Various macromolecules are known to be transported through PD in a highly regulated manner, and plant viruses utilize their movement proteins (MPs) to gate the PD to spread cell-to-cell. The mechanism by which MP modifies PD to enable intercelluar traffic remains obscure, due to the lack of knowledge about the host factors that mediate the process. Here, we describe the functional interaction between Tobacco mosaic virus (TMV) MP and a plant factor, an ankyrin repeat containing protein (ANK), during the viral cell-to-cell movement. We utilized a reverse genetics approach to gain insight into the possible involvement of ANK in viral movement. To this end, ANK overexpressor and suppressor lines were generated, and the movement of MP was tested. MP movement was facilitated in the ANK-overexpressing plants, and reduced in the ANK-suppressing plants, demonstrating that ANK is a host factor that facilitates MP cell-to-cell movement. Also, the TMV local infection was largely delayed in the ANK-suppressing lines, while enhanced in the ANK-overexpressing lines, showing that ANK is crucially involved in the infection process. Importantly, MP interacted with ANK at PD. Finally, simultaneous expression of MP and ANK markedly decreased the PD levels of callose, β-1,3-glucan, which is known to act as a molecular sphincter for PD. Thus, the MP-ANK interaction results in the downregulation of callose and increased cell-to-cell movement of the viral protein. These findings suggest that ANK represents a host cellular receptor exploited by MP to aid viral movement by gating PD through relaxation of their callose sphincters

Old world vultures in a changing environment

Carrion is a pulsed food resource of unpredictable occurrence in space and time that offers a high nutritive biomass, but is not globally widespread across all habitats and territories, and can be considered free because it does not require a large physical investment derived from predation (Ostfeld and Keesing 2000; DeVault et al. 2003; Selva and Fortuna 2007; Barton et al. 2013; Moleón et al. 2014a). As a result of these features, organisms feeding on this resource have developed morphological and behavioural adaptations to optimise its exploitation (Hertel 1994; DeVault et al. 2003; Moreno-Opo et al. 2015a, 2016), establishing guilds of species as in the case of carrion-eating birds (Selva and Fortuna 2007). Among terrestrial vertebrates, only vultures (families Accipitridae and Cathartidae) have evolved into obligate scavengers (DeVault et al. 2003; Beasley et al. 2015; Moleón et al. 2014b). Scavengers exploit carrion at different levels of intensity, and depending on their degree of carrion consumption and their own adaptive traits, they are defined as either obligate or facultative (DeVault et al. 2003; Wilson and Wolkovich 2011). As a result of the unpredictability in the availability of carcasses, the proportion of obligate scavenger species are scarce in comparison with facultative species that scavenge at variable rates but that can subsist on other food resources in the absence of carrion (DeVault et al. 2003; Beasley et al. 2015; Mateo-Tomás et al. 2015).A. M. was supported by a Ramón y Cajal research contract by the Ministry of Economy and Competitiveness (RYC-2012-11867).Peer reviewe