Structure of an HIF-1alpha -pVHL complex: hydroxyproline recognition in signaling

The ubiquitination of the hypoxia-inducible factor (HIF) by the von Hippel-Lindau tumor suppressor (pVHL) plays a central role in the cellular response to changes in oxygen availability. pVHL binds to HIF only when a conserved proline in HIF is hydroxylated, a modification that is oxygen-dependent. The 1.85 angstrom structure of a 20-residue HIF-1alpha peptide-pVHL-ElonginB-ElonginC complex shows that HIF-1alpha binds to pVHL in an extended beta strand-like conformation. The hydroxyproline inserts into a gap in the pVHL hydrophobic core, at a site that is a hotspot for tumorigenic mutations, with its 4-hydroxyl group recognized by buried serine and histidine residues. Although the beta sheet-like interactions contribute to the stability of the complex, the hydroxyproline contacts are central to the strict specificity characteristic of signaling.     

School food environments and the obesity issue: content,structural determinants,and agency in Canadian high schools

To understand the phenomenon of the rapidly increasing prevalence of overweight and obese children and youth, it is especially important to examine the school food environment, the role of structural factors in shaping this environment, and the resulting nutrition and health outcomes. The paper examines research on school food environments in the US and Canada. It notes evidence of widespread availability of poor nutrition products in both environments and delineates reasons for the situation, and examines initiatives presently being undertaken in a number of jurisdictions in both countries to encourage healthy eating in schools. Empirical data are presented from a pilot study of high schools in the Canadian province of Ontario. The study documents the extent of student purchasing of nutrient-poor foods and beverages, and the structural factors internal and external to the school that appear responsible for the availability of such products in food environments in this critical institutional sphere. The paper also examines positive local initiatives in high schools that seek to encourage healthy eating in schools.

Taste nerve fibers: a random distribution of sensitivities to four tastes

The numbers of rat glossopharyngeal and chorda tympani fibers responding to one, two, three, or four taste stimuli of different quality (sodium chloride, hydrochloric acid, quinine, and sucrose) and to each of the six possible pairs of these stimuli can be predicted if there are four independent sensitivities randomly distributed among innervating fibers.     

Action spectra for phase shifts of a circadian rhythm in Drosophila

Action spectra were determined for lightinduced phase shifts of the circadian rhythm of adult emergence in Drosophila pseudoobscura. The action spectra for advance and delay phase shifts are similar; the most effective wavelengths are in the blue region, with a sharp cutoff above 500 nanometers. This similarity suggests that the same photoreceptive pigment mediates both advance and delay phase shifts.     

The illusion of control: industrialized agriculture,nature, and food safety

I explore the role of nature in the agrifood system and how attempts to fit food production into a large-scale manufacturing model has lead to widespread outbreaks of food borne illness. I illustrate how industrial processing of leafy greens is related to the outbreak of E. coli 0157:H7 associated with spinach in the fall of 2006. I also use this example to show how industry attempts to create the illusion of control while failing to address weaknesses in current processing systems. The leafy greens industry has focused efforts on sterilizing the growing environment and adopting new technologies, while neglecting to change the concentrated structure of processing systems. Repeated breakdowns in these systems illustrate a widening fault line between attempted and failed control of nature in industrial food production.

Intestinal calcium transport: stimulation by low phosphorus diets

Rats maintained on a low phosphorus diet supplemented with 25-hydroxyvitamin D(3) show high intestinal calcium transport activity as compared to rats similarly treated but fed a diet containing adequate phosphorus. This increased transport activity is correlated with an increased biosynthesis of 1,25-dihydroxyvitamin D(3), the probable metabolically active form of the vitamin in the intestine.     

Growth and fatty acid composition of sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.) genotypes as influence by planting dates and nitrogen fertilization in semiarid region of Northwest,Pakistan

A field experiment was conducted on silty clay loam soil in the years 2011–2012. Two sesame (Sesamum indicum L.) cultivars (Local Black and Local White) were evaluated using various 3 different sowing dates (20th June, 10th and 30th July) and four agrotechnical level (0, 40, 80 and 120 kg N ha^–1) at New Developmental Farm The University of Agriculture, Peshawar, Pakistan. The objective of this study was to evaluate the effects of sowing dates on growth, yield and oil fatty acid composition of two sesame cultivars grown under different nitrogen fertilization. Results showed that cv. Local Black was characterized by significantly higher content of oil (47%), seed yield (696 kg ha^–1) and oil yield (335 kg ha^–1) while cv. Local White had higher palmitic acid (8%) and linoleic acid (38.7%). Yield and its main components were positively affected by the earlier sowing date. With regard to fatty acid composition, a decrease in oleic and stearic acid and an increase in linoleic and palmitic acid were observed. At early sowing, oleic and palmitic acid decreased whereas linoleic and stearic acid increased. The decrease in the oleic/linoleic acid ratio observed at early sowing, suggests a possible role of temperature on the activity of oleate desaturase in the developing seeds. Intensive technology of cultivation (120 kg N ha^–1), compared to the economical technology (40 kg N ha^–1), significantly increased the seed yield of both sesame cultivars. This was due to higher number of branches, Capsules m^–2, capsules plant^–1, seeds capsule^–1 and 1000 seed weight (g). The intensive technology of cultivation had a beneficial effect on the content of palmitic acid, linolenic acid and oleic acid in sesame seed.     

Improved remote sensing detection of wheat powdery mildew using dual-green vegetation indices

In this study, we investigated the possibility of using ground-based remote sensing technology to estimate powdery mildew disease severity in winter wheat. Using artificially inoculated fields, potted plants, and disease nursery tests, we measured the powdery mildew canopy spectra of varieties of wheat at different levels of incidence and growth stages to investigate the disease severity. The results showed that the powdery mildew sensitive bands were between 580 and 710 nm. The best two-band vegetation index that correlated with wheat powdery mildew between 400 and 1000 nm wavelength were the normalized spectrum 570–590 and 536–566 nm bands for the ratio index, and 568–592 and 528–570 nm for the normalized difference index. The coefficients of determination (R ²) for both were almost the same. The optimum dual-green vegetation index was constructed based on a calculation of the ratio and normalized difference between the normalized spectrum within the two green bands. The coefficients of determination (R ²) of DGSR (584, 550) (dual-green simple ratio) and DGND (584, 550) (dual-green normalized difference) were both 0.845. The inverse models of disease severity performed well in the test process at the canopy scale, and indicated that, compared with the traditional vegetation indices of Lwidth, mND705, ND (SDr, SDb), SIPI, and GNDVI, the novel dual-green indices greatly improved the remote sensing detection of wheat powdery mildew disease. Following these results, combined disease severity and canopy spectra were shown to be of enormous value when applied to the accurate monitoring, prevention, and control of crop diseases.     

Inhibition of the complement cascade by the major secretory protein of vaccinia virus

The complement system contributes to host defenses against invasion by infectious agents. A 35-kilodalton protein, encoded by vaccinia virus and secreted from infected cells, has sequence similarities to members of a gene family that includes complement control proteins. Biochemical and genetic studies showed that the viral protein binds to derivatives of the fourth component of complement and inhibits the classical complement cascade, suggesting that it serves as a defense molecule to help the virus evade the consequences of complement activation.     

Conserving copalillo: The creation of sustainable Oaxacan wood carvings

Most accounts of the effect of the global marketplace on deforestation in Africa, Asia, and Latin America emphasize the demand for timber used in industrial processes and the conversion of tropical forests to pastures for beef cattle. In recent years, numerous scholars and policymakers have suggested that developing a market for non-timber forest products (NTFPs) might slow the pace of habitat destruction. Although increased demand for NTFPs rarely results in massive deforestation, the depletion of the raw materials needed to make particular products is common. Many rural households in the Mexican state of Oaxaca have prospered over the past three decades through the sale of brightly-painted, whimsical wood carvings (alebrijes) to international tourists and the owners of ethnic arts shops in the United States, Canada, and Europe. This paper examines a promising project aimed at providing Oaxacan alebrije-makers with a reliable, legal, and sustainable supply of wood. The ecologists, artisans, merchants, and forest owners involved in the project face formidable obstacles. Gaining permission to harvest wood from land belonging to Oaxacan communities requires the negotiation of a complex social, legal, economic, and political landscape. Artisans’ decisions about where to obtain wood rest largely on price, quality, and reliability of the supplier; they are willing to pay a premium for ecologically sustainable wood only if the additional cost can be passed on to consumers. Nonetheless, a group of carvers has begun to buy sustainably harvested wood. This arrangement has economic advantages for both the alebrije-makers and the owners of the forests where the wood is produced. Michael Chibnik is Professor of Anthropology at the University of Iowa. He has conducted fieldwork in Belize, Peru, Mexico, and in various parts of the United States. His research interests include economic anthropology, artisans, work organization, agricultural decision-making, and political ecology. He is the author of Crafting Tradition: The Making and Marketing of Oaxacan Wood Carvings (University of Texas Press, 2003) and Risky Rivers: The Economics and Politics of Floodplain Farming in Amazonia (University of Arizona Press, 1994), and editor of Farm Work and Fieldwork: American Agriculture in Anthropological Perspective (Cornell University Press, 1987). Dr. Silvia E. Purata is a Mexican ethnoecologist based in Xalapa, Veracruz. She is a member of People and Plants International, an organization that works to integrate conservation and the use of natural resources. Purata has conducted research on the methods indigenous peoples use to extract non-timber forest products (NTFPs) in tropical forests and the fate of such systems in varying socioeconomic circumstances. She has also been working on the promotion of forest certification in the Selva Maya.