Lysosomal enzyme inhibition by trypan blue: a theory of teratogenesis

A mechanism of mammalian teratogenesis involving inhibition of embryotrophic nutrition is suggested and exemplified by the action of trypan blue on pregnant rats. There is evidence for the localization of trypan blue in heterolysosomes of the epithelium of the visceral yolk sac, and our experiments indicate that the dye is an inhibitor of a selection of hydrolytic enzymes present in lysosomal fractions from homogenates of rat visceral yolk sac. It seems likely that trypan blue inhibits the intracellular digestion of embryotroph by the visceral yolk-sac epithelium; the conceptus may therefore be deprived of essential nutrients at critical stages of development.     

Superiority, competition, and opportunism in the evolutionary radiation of dinosaurs

The rise and diversification of the dinosaurs in the Late Triassic, from 230 to 200 million years ago, is a classic example of an evolutionary radiation with supposed competitive replacement. A comparison of evolutionary rates and morphological disparity of basal dinosaurs and their chief "competitors," the crurotarsan archosaurs, shows that dinosaurs exhibited lower disparity and an indistinguishable rate of character evolution. The radiation of Triassic archosaurs as a whole is characterized by declining evolutionary rates and increasing disparity, suggesting a decoupling of character evolution from body plan variety. The results strongly suggest that historical contingency, rather than prolonged competition or general "superiority," was the primary factor in the rise of dinosaurs.     

Quantum coherent tunable coupling of superconducting qubits

To do large-scale quantum information processing, it is necessary to control the interactions between individual qubits while retaining quantum coherence. To this end, superconducting circuits allow for a high degree of flexibility. We report on the time-domain tunable coupling of optimally biased superconducting flux qubits. By modulating the nonlinear inductance of an additional coupling element, we parametrically induced a two-qubit transition that was otherwise forbidden. We observed an on/off coupling ratio of 19 and were able to demonstrate a simple quantum protocol.     

Tourism and transitional geographies: Mismatched expectations of tourism investment in Vietnam*

Abstract: The Vietnamese state's interaction with international capital has been influenced by the Communist Party's strategy to develop a ‘socialist market economy’ which aims to maintain the leading role of the state and its one party dominance while implementing economic reforms. This is at odds with alternatives proposed by neo‐liberal institutions such as the IMF and World Bank who favour a progression towards a more fully‐fledged market economy coupled with political pluralism. As a result, foreign investors and the Vietnamese government have had a turbulent relationship over the past decade stemming in large part from differing perceptions of a market economy and what foreign investment should entail. This paper depicts the principal issues that lay behind the restrictive policies toward foreign tour operators through a case study of their management and regulation in Vietnam throughout the 1990s. It is argued that foreign tour operators and Vietnamese tourism authorities perceive the role of international capital in tour operations quite differently. Over‐regulation has provided little space for foreign tour businesses to operate in a manner that has met their expectations, while government policies have been intent on ensuring that profits remain in the country. This paper also illustrates how social networks undermine top‐down government policy directives and allow foreign tour businesses to continue operating, albeit in a complex and insecure environment.     

Reduction of fumonisin B1 in corn grits by single-screw extrusion

This study was designed to determine the efficacy of extrusion in reducing fumonisin B1 in corn flaking grits in the presence and absence of glucose. In addition, degradation products of fumonisin B1 during extrusion were identified and quantitated with a mass balance approach. Uncontaminated clean corn grits, grits spiked with 30 microg/g fumonisin B1, and grits fermented with Fusarium verticillioides M-2552 (40-50 microg/g fumonisin B1) were extruded in the presence and absence of glucose (10%, w/w) using a single-screw extruder. Extrusion decreased fumonisin B1 by 21-37%, whereas the same process with added glucose further decreased fumonisin B1 by 77-87%. LC-fluorescence and LC-MS showed that most fumonisin in the extruded samples without added glucose was the fumonisin B1 form, whereas the main degradation product in grits extruded with glucose was N-(deoxy- d-fructos-1-yl)fumonisin B1. The formation of hydrolyzed fumonisin B1 was not significant during extrusion. Results suggest that extrusion in the presence of glucose may reduce fumonisin B1 in corn grits significantly.     

Eimeria stiedae causes most of the white-spotted liver lesions in wild European rabbits in Cambridgeshire,United Kingdom

In rabbits, a white-spotted liver can be indicative of one of several disease processes, frequently caused by parasites. To date, the prevalence of white-spotted liver in wild rabbits, Oryctolagus cuniculus, in the United Kingdom is undetermined. We evaluated the prevalence and main parasitic etiologies of this entity in a U.K. population of wild rabbits. Wild rabbits (n = 87) were shot in Cambridgeshire for population control, and cadavers were donated for research. Postmortem examination was undertaken, including gross and histologic hepatic examination. Macroscopic lesions consistent with white-spotted liver were found in 46 of 87 (53%) rabbits examined; most of these lesions were considered to be mild. For 28 of 46 (59%) rabbits with gross hepatic lesions, an etiologic agent was apparent histologically. Eimeria stiedae was detected in 21 of 87 (24%) rabbits, and Calodium hepaticum (syn. Capillaria hepatica) was detected in 7 of 87 (8%). In the subset of rabbits killed in the summer, there was a significant association between white-spotted liver and juvenile age class. There was also an association between white-spotted liver caused by E. stiedae and juvenile age class. When restricting analysis to rabbits with white-spotted liver caused by E. stiedae and submitted in the summer, both juvenile age class and female had significant effects. E. stiedae and C. hepaticum can be transmitted to pet lagomorphs via contaminated vegetation, and to humans in the case of the latter, which demonstrates the importance of monitoring the prevalence of these parasitic diseases in wild rabbits.     

Lymphocyte reactivity to antigens of Haemonchus contortus in antigen-inoculated and H contortus-naive lambs.

Lambs were inoculated during either fetal or early neonatal life with antigens of Haemonchus contortus (HcAg) third-stage larvae, or ovalbumin (OVA), or were left untreated. By the time lambs were 4 weeks old, blood lymphocytes from all of them responded to HcAg. This was evident in all lambs, regardless of the previous inoculation regimen, although higher response was seen in HcAg-inoculated lambs, compared with naive lambs. Only lambs inoculated with OVA had OVA-specific lymphocyte activity. In HcAg-naive lambs, the maximal HcAg lymphocyte response was observed between the ages of 5 and 25 weeks, with gradual decrease thereafter. In vitro detection of HcAg-reactive lymphocytes was affected by antigen concentration and presence of plasma. Plasma inhibited HcAg-reactive lymphocytes from all lambs at high in vitro antigen concentration and completely abrogated the response in H contortus antigen-naive lambs.