Identifying C. elegans Lifespan Mutants by Screening for Early-Onset Protein Aggregation

Genetic screens have been widely used to identify genetic pathways that control specific biological functions. In C. elegans, forward genetic screens rely on the isolation of reproductively active mutants that can self-propagate clonal populations. Since aged individuals are unable to generate clonal populations, screens that target post-reproductive phenotypes, such as longevity, are challenging. In this work, we developed an approach that combines microfluidic technologies and image processing to perform a high-throughput, automated screen for mutants with shortened lifespan using protein aggregation as a marker for aging. We take advantage of microfluidics for maintaining a reproductively-active adult mutagenized population and for performing serial high-throughput analysis and sorting of animals with increased protein aggregation, using fluorescently labeled PAB-1 as a readout. We identified five mutants with increased aggregation levels, of which two exhibited a reduced lifespan. We demonstrate that lifespan mutants can be identified by screening for accelerated protein aggregation through quantitative analysis of fluorescently-labeled aggregates in populations that do not require conditional sterilization or manual separation of parental and progeny populations. We further analyzed the morphology of protein aggregates and reveal that patterns of aggregation in naturally-aging animals differ from mutants with increased aggregation, suggesting aggregate growth is time-dependent. This screening approach can be customized to other non-developmental phenotypes that appear during adulthood, as well as to other aging markers to identify additional longevity-regulating genetic pathways.

ATP and Tri-Polyphosphate (TPP) Suppress Protein Aggregate Growth by a Supercharging Mechanism

A common strategy to increase aggregation resistance is through rational mutagenesis to supercharge proteins, which leads to high colloidal stability, but often has the undesirable effect of lowering conformational stability. We show this trade-off can be overcome by using small multivalent polyphosphate ions, adenosine triphosphate (ATP) and tripolyphosphate (TPP) as excipients. These ions are equally effective at suppressing aggregation of ovalbumin and bovine serum albumin (BSA) upon thermal stress as monitored by dynamic and static light scattering. Monomer loss kinetic studies, combined with measurements of native state protein–protein interactions and ζ-potentials, indicate the ions reduce aggregate growth by increasing the protein colloidal stability through binding and overcharging the protein. Out of three additional proteins studied, ribonuclease A (RNaseA), α-chymotrypsinogen (α-Cgn), and lysozyme, we only observed a reduction in aggregate growth for RNaseA, although overcharging by the poly-phosphate ions still occurs for lysozyme and α-Cgn. Because the salts do not alter protein conformational stability, using them as excipients could be a promising strategy for stabilizing biopharmaceuticals once the protein structural factors that determine whether multivalent ion binding will increase colloidal stability are better elucidated. Our findings also have biological implications. Recently, it has been proposed that ATP also plays an important role in maintaining intracellular biological condensates and preventing protein aggregation in densely packed cellular environments. We expect electrostatic interactions are a significant factor in determining the stabilizing ability of ATP towards maintaining proteins in non-dispersed states in vivo.

Sectoral analysis of foreign direct investment and growth in Nigeria

The study conducted a sectoral analysis of the contribution of foreign direct investment on Nigeria economy between 1980-2019. Time series data from Central Bank of Nigeria and World Bank Development Indicators was used to estimate the relationship using Auto Distributed Lag Model (ARDL). It was revealed that foreign direct investment not only exert a direct positive effect on the aggregate growth rate of Nigeria economy but also exert a positive indirect effect through labour. It was also discovered that agriculture sector is the only sector that does not enjoy significant contribution of foreign direct investment in Nigeria while petroleum and Gas experience the greatest growth attributable to foreign direct investment in Nigeria. The study contributed to literature by not only examining the indirect effect of foreign direct investment on Nigeria aggregate growth rate through labour but also the effect of foreign direct investment on the sector-by-sector growth rate.

A Year of Covid-19: A Long Road to Recovery and Acceleration of Indonesia's Development

2020 is the year of Covid-19, Indonesia feels the enormity of this pandemic in various aspects of development. The Indonesian economy during the year slowed down to minus 5.3 percent in the second quarter of 2020 and in aggregate growth was minus 2.1 percent in 2020. The target of development planning in the National Medium Term Development Plan (Rencana Pembangunan Jangka Menengah/RPJMN) 2020-2024 was revised through the updating of the Government Work Plan (Rencana Kerja Pemerintah/RKP) in 2020, with the main priority of overcoming Covid-19. Then development began to be intensified in 2021 to pursue national priority targets that were abandoned due to Covid-19. The 2020 State Budget allocates around IDR 937.42 trillion for the prevention of Covid-19, including the accumulated APBD (Regional Revenue and Expenditure Budget) IDR 86.32 trillion, which makes the deficit financing for that year reach IDR 1,226.8 trillion. The Covid-19 pandemic control policy through Large-Scale Social Restrictions Policy (Pembatasan Sosial Berskala Besar/PSBB) has had ups and downs, especially when coupled with the new normal policy. The Policy for Limiting Micro-Community Activities (Pemberlakuan Pembatasan Kegiatan Masyarakat/PPKM) as a substitute for PSBB was implemented in early February and the parallel national vaccination program is expected to support accelerated development as outlined in the RKP 2021. In 2021, the Covid-19 pandemic is still high in the world, and the acceleration of development proclaimed by the government gets a stretch of road that extends to be traversed.

The Rise of the Service Sector in the Global Economy

This chapter examines the implications of the rapid rise of the service sector in the global economy and sub-Saharan Africa. The chapter discusses the growing importance of the service sector and key issues such as service sector productivity, the contribution of the service sector to aggregate growth and productivity, and the potentially positive contributions of services to other sectors. The review touches upon key issues such as the Baumol hypothesis of a stagnant service sector. The second half of the chapter focuses on tertiarization trends in sub-Saharan Africa. The chapter finds robust evidence of relationships between development in services and manufacturing performance and evidence of strong inter-industry linkages between the service sector and manufacturing. Countries differ in terms of which specific service sectors matter for manufacturing performance. It is important for policymakers to take these trends into consideration in industrial policy design to achieve the optimal outcome from any such policy.

Pathway Complexity in Supramolecular Porphyrin Self-Assembly at an Immiscible Liquid|Liquid Interface

<p>Nanostructures that are inaccessible through spontaneous thermodynamic processes may be formed by supramolecular self-assembly under kinetic control. In the past decade, the dynamics of pathway complexity in self-assembly have been elucidated through kinetic models based on aggregate growth by sequential monomer association and dissociation. Immiscible liquid|liquid interfaces are an attractive platform to develop well-ordered self-assembled nanostructures, unattainable in bulk solution, due to the templating interaction of the interface with adsorbed molecules. Here, we report time-resolved <i>in situ</i> UV/vis spectroscopic observations of the self-assembly of zinc(II) meso-tetrakis(4-carboxyphenyl)porphyrin (ZnTPPc) at an immiscible aqueous|organic interface. We show that the kinetically favoured metastable J-type nanostructures form quickly, but then transform into stable thermodynamically favoured H-type nanostructures. Numerical modelling revealed two parallel and competing cooperative pathways leading to the different porphyrin nanostructures. These insights demonstrate that pathway complexity is not unique to self-assembly processes in bulk solution, and equally valid for interfacial self-assembly. Subsequently, the interfacial electrostatic environment was tuned using a kosmotropic anion (citrate) in order to control the influence the pathway selection. At high concentrations, interfacial nanostructure formation was forced completely down the kinetically favoured pathway and only J-type nanostructures were obtained. Furthermore, we found by atomic force microscopy (AFM) and scanning electron microscopy (SEM) that the J- and H-type nanostructures obtained at low and high citric acid concentrations, respectively, are morphologically distinct, which illustrates the pathway-dependent material properties.</p>