2,567 research outputs found

    Starvation Induces Proteasome Autophagy with Different Pathways for Core and Regulatory Particles

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    Citation: Waite, K. A., De-La Mota-Peynado, A., Vontz, G., & Roelofs, J. (2016). Starvation Induces Proteasome Autophagy with Different Pathways for Core and Regulatory Particles. Journal of Biological Chemistry, 291(7), 3239-3253. doi:10.1074/jbc.M115.699124The proteasome is responsible for the degradation of many cellular proteins. If and how this abundant and normally stable complex is degraded by cells is largely unknown. Here we show that in yeast, upon nitrogen starvation, proteasomes are targeted for vacuolar degradation through autophagy. Using GFP-tagged proteasome subunits, we observed that autophagy of a core particle (CP) subunit depends on the deubiquitinating enzyme Ubp3, although a regulatory particle (RP) subunit does not. Furthermore, upon blocking of autophagy, RP remained largely nuclear, although CP largely localized to the cytosol as well as granular structures within the cytosol. In all, our data reveal a regulated process for the removal of proteasomes upon nitrogen starvation. This process involves CP and RP dissociation, nuclear export, and independent vacuolar targeting of CP and RP. Thus, in addition to the well characterized transcriptional up-regulation of genes encoding proteasome subunits, cells are also capable of down-regulating cellular levels of proteasomes through proteaphagy

    Ministerial directives to local government in Zimbabwe: top-down governance in a decentralized constitution

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    Urban and rural local authorities constitute the lowest tier of Zimbabwe's multilevel system of government. These local governments have a constitutional "right to govern" that must be exercised within the constitutional, legislative and policy framework. Under the old constitutional order, the national government could supervise urban local authorities, for example by issuing policy directives to ensure that these authorities governed in a manner that enabled them to deliver on national and local goals. This article examines this supervisory instrument, the powers it gives the national government, its use in practice and its relevance under the new constitutional order. The main argument is that supervisory instruments, such as the power to issue policy directives to local governments, are necessary in any multilevel system of government. However, such supervisory powers must be balanced with the need for local autonomy, to allow local governments to deliver on their service delivery obligations and development mandate.IS

    Heating Titan's upper atmosphere

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95339/1/jgra19338.pd

    Determining ‘Age at Death’ for Forensic Purposes using Human Bone by a Laboratory-based Analytical Method

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    Determination of age-at-death (AAD) is an important and frequent requirement in contemporary forensic science and in the reconstruction of past populations and societies from their remains. Its estimation is relatively straightforward and accurate (±3 years) for immature skeletons by using morphological features and reference tables within the context of forensic anthropology. However, after skeletal maturity (>35 yrs) estimates become inaccurate, particularly in the legal context. In line with the general migration of all the forensic sciences from reliance upon empirical criteria to those which are more evidence-based, AAD determination should rely more-and-more upon more quantitative methods. We explore here whether well-known changes in the biomechanical properties of bone and the properties of bone matrix, which have been seen to change with age even after skeletal maturity in a traceable manner, can be used to provide a reliable estimate of AAD. This method charts a combination of physical characteristics some of which are measured at a macroscopic level (wet & dry apparent density, porosity, organic/mineral/water fractions, collagen thermal degradation properties, ash content) and others at the microscopic level (Ca/P ratios, osteonal and matrix microhardness, image analysis of sections). This method produced successful age estimates on a cohort of 12 donors of age 53–85 yr (7 male, 5 female), where the age of the individual could be approximated within less than ±1 yr. This represents a vastly improved level of accuracy than currently extant age estimation techniques. It also presents: (1) a greater level of reliability and objectivity as the results are not dependent on the experience and expertise of the observer, as is so often the case in forensic skeletal age estimation methods; (2) it is purely laboratory-based analytical technique which can be carried out by someone with technical skills and not the specialised forensic anthropology experience; (3) it can be applied worldwide following stringent laboratory protocols. As such, this technique contributes significantly to improving age estimation and therefore identification methods for forensic and other purposes

    Metabolic pathways inferred from a bacterial marker gene illuminate ecological changes across South Pacific frontal boundaries

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    Global oceanographic monitoring initiatives originally measured abiotic essential ocean variables but are currently incorporating biological and metagenomic sampling programs. There is, however, a large knowledge gap on how to infer bacterial functions, the information sought by biogeochemists, ecologists, and modelers, from the bacterial taxonomic information (produced by bacterial marker gene surveys). Here, we provide a correlative understanding of how a bacterial marker gene (16S rRNA) can be used to infer latitudinal trends for metabolic pathways in global monitoring campaigns. From a transect spanning 7000 km in the South Pacific Ocean we infer ten metabolic pathways from 16S rRNA gene sequences and 11 corresponding metagenome samples, which relate to metabolic processes of primary productivity, temperature-regulated thermodynamic effects, coping strategies for nutrient limitation, energy metabolism, and organic matter degradation. This study demonstrates that low-cost, high-throughput bacterial marker gene data, can be used to infer shifts in the metabolic strategies at the community scale
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