AFTER THE NIXON RESIGNATION WE STILL NEED REFORM!

Agricultural and Food Policy,

AGRICULTURE IN THE NATION'S POLITICS

Political Economy,

FARM POLITICS AND THE SEPARATION OF POWERS

Agricultural and Food Policy,

Specific Interaction of Glyceraldehyde 3-Phosphate Dehydrogenase with the 5′-Nontranslated RNA of Hepatitis A Virus

Initiation of translation of hepatitis A virus (HAV) RNA occurs by internal entry and is likely to involve the interaction of trans-acting cellular protein factors with cis-acting structural elements of an internal ribosomal entry segment (IRES) within the 5'-nontranslated RNA. To characterize interactions between African green monkey kidney (BS-C-1) cell proteins and the predicted stem-loop IIIa (nucleotides 155-235) located at the 5' border of the HAV IRES, we utilized an electrophoresis mobility shift assay (EMSA) to identify a 39-kDa RNA-binding protein (p39). Amino-terminal amino acid sequencing of highly purified p39 revealed absolute identity with human glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The identity of p39 as simian GAPDH was further confirmed by antigenic and biochemical similarities between p39 and human GAPDH. Analysis of the RNA binding properties of simian GAPDH revealed that this cellular protein interacts with two additional sites in the HAV 5'-nontranslated RNA, one located between nucleotides 1-148 and the other between nucleotides 597-746. Competitive EMSAs also demonstrated that GAPDH and human polypyrimidine tract-binding protein, a putative picornavirus translation initiation factor, compete with each other for binding to stem-loop IIIa, suggesting that the relative cytoplasmic abundance of GAPDH and polypyrimidine tract-binding protein in individual cell-types may be an important determinant of viral translation activity. Human GAPDH was found to destabilize the folded structure of the stem-loop IIIa RNA based upon observed decreases in the circular dichroism spectra of this RNA following binding of the protein. This RNA helix-destabilizing activity of GAPDH could directly influence IRES-dependent translation and/or replication of picornavirus RNA

Integrating tropical research into biology education is urgently needed

Understanding tropical biology is important for solving complex problems such as climate change, biodiversity loss, and zoonotic pandemics, but biology curricula view research mostly via a temperatezone lens. Integrating tropical research into biology education is urgently needed to tackle these issues. The tropics are engines of Earth systems that regulate global cycles of carbon and water, and are thus critical for management of greenhouse gases. Compared with higher-latitude areas, tropical regions contain a greater diversity of biomes, organisms, and complexity of biological interactions. The tropics house the majority of the world’s human population and provide important global commodities from species that originated there: coffee, chocolate, palm oil, and species that yield the cancer drugs vincristine and vinblastine. Tropical regions, especially biodiversity hotspots, harbor zoonoses, thereby having an important role in emerging infectious diseases amidst the complex interactions of global environmental change and wildlife migration [1]. These well-known roles are oversimplified, but serve to highlight the global biological importance of tropical systems. Despite the importance of tropical regions, biology curricula worldwide generally lack coverage of tropical research. Given logistical, economic, or other barriers, it is difficult for undergraduate biology instructors to provide their students with field-based experience in tropical biology research in a diverse range of settings, an issue exacerbated by the Coronavirus Disease 2019 (COVID-19) pandemic. Even in the tropics, field-based experience may be limited to home regions. When tropical biology is introduced in curricula, it is often through a temperate- zone lens that does not do justice to the distinct ecosystems, sociopolitical histories, and conservation issues that exist across tropical countries and regions [2]. The tropics are often caricatured as distant locations known for their remarkable biodiversity, complicated species interactions, and unchecked deforestation. This presentation, often originating from a colonial and culturally biased perspective, may fail to highlight the role of tropical ecosystems in global environmental and social challenges that accompany rising temperatures, worldwide biodiversity loss, zoonotic pandemics, and the environmental costs of ensuring food, water, and other ecosystem services for humans [3]

The Hubble Higher-Z Supernova Search: Supernovae to z=1.6 and Constraints on Type Ia Progenitor Models

We present results from the Hubble Higher-z Supernova Search, the first space-based open field survey for supernovae (SNe). In cooperation with the Great Observatories Origins Deep Survey, we have used the Hubble Space Telescope with the Advanced Camera for Surveys to cover 300 square arcmin in the area of the Chandra Deep Field South and the Hubble Deep Field North on five separate search epochs (separated by 45 day intervals) to a limiting magnitude of z'=26. These deep observations have allowed us to discover 42 SNe in the redshift range 0.2 < z < 1.6. As these data span a large range in redshift, they are ideal for testing the validity of Type Ia supernova progenitor models with the distribution of expected ``delay times,'' from progenitor star formation to SN Ia explosion, and the SN rates these models predict. Through a Bayesian maximum likelihood test, we determine which delay-time models best reproduce the redshift distribution of SNe Ia discovered in this survey. We find that models that require a large fraction of ``prompt'' (less than 2 Gyr) SNe Ia poorly reproduce the observed redshift distribution and are rejected at 95% confidence. We find that Gaussian models best fit the observed data for mean delay times in the range of 3 to 4 Gyr.Comment: 32 pages, 15 figures, accepted for publication in the Astrophysical Journa

The Caenorhabditis elegans GATA Factor ELT-1 Works through the Cell Proliferation Regulator BRO-1 and the Fusogen EFF-1 to Maintain the Seam Stem-Like Fate

Seam cells in Caenorhabditis elegans provide a paradigm for the stem cell mode of division, with the ability to both self-renew and produce daughters that differentiate. The transcription factor RNT-1 and its DNA binding partner BRO-1 (homologues of the mammalian cancer-associated stem cell regulators RUNX and CBFβ, respectively) are known rate-limiting regulators of seam cell proliferation. Here, we show, using a combination of comparative genomics and DNA binding assays, that bro-1 expression is directly regulated by the GATA factor ELT-1. elt-1(RNAi) animals display similar seam cell lineage defects to bro-1 mutants, but have an additional phenotype in which seam cells lose their stem cell-like properties and differentiate inappropriately by fusing with the hyp7 epidermal syncytium. This phenotype is dependent on the fusogen EFF-1, which we show is repressed by ELT-1 in seam cells. Overall, our data suggest that ELT-1 has dual roles in the stem-like seam cells, acting both to promote proliferation and prevent differentiation

Economic Analysis of Knowledge: The History of Thought and the Central Themes

Following the development of knowledge economies, there has been a rapid expansion of economic analysis of knowledge, both in the context of technological knowledge in particular and the decision theory in general. This paper surveys this literature by identifying the main themes and contributions and outlines the future prospects of the discipline. The wide scope of knowledge related questions in terms of applicability and alternative approaches has led to the fragmentation of research. Nevertheless, one can identify a continuing tradition which analyses various aspects of the generation, dissemination and use of knowledge in the economy