The multimedia brain

The Open University is producing an interactive multimedia tutorial on the brain and nervous system on CD-ROM, for use in its Biology: Brain and Behaviour course. Such a tutor could have a wider use in higher education as the subject matter is known to be difficult for students to master. A prototype version has been produced. Consultation is now taking place before work starts on a fully functional version that can be evaluated for educational effectiveness

Structure of the herpes-simplex virus portal-vertex

Herpesviruses include many important human pathogens such as herpes simplex virus, cytomegalovirus, varicella-zoster virus, and the oncogenic Epstein–Barr virus and Kaposi sarcoma–associated herpesvirus. Herpes virions contain a large icosahedral capsid that has a portal at a unique 5-fold vertex, similar to that seen in the tailed bacteriophages. The portal is a molecular motor through which the viral genome enters the capsid during virion morphogenesis. The genome also exits the capsid through the portal-vertex when it is injected through the nuclear pore into the nucleus of a new host cell to initiate infection. Structural investigations of the herpesvirus portal-vertex have proven challenging, owing to the small size of the tail-like portal-vertex–associated tegument (PVAT) and the presence of the tegument layer that lays between the nucleocapsid and the viral envelope, obscuring the view of the portal-vertex. Here, we show the structure of the herpes simplex virus portal-vertex at subnanometer resolution, solved by electron cryomicroscopy (cryoEM) and single-particle 3D reconstruction. This led to a number of new discoveries, including the presence of two previously unknown portal-associated structures that occupy the sites normally taken by the penton and the Ta triplex. Our data revealed that the PVAT is composed of 10 copies of the C-terminal domain of pUL25, which are uniquely arranged as two tiers of star-shaped density. Our 3D reconstruction of the portal-vertex also shows that one end of the viral genome extends outside the portal in the manner described for some bacteriophages but not previously seen in any eukaryote viruses. Finally, we show that the viral genome is consistently packed in a highly ordered left-handed spool to form concentric shells of DNA. Our data provide new insights into the structure of a molecular machine critical to the biology of an important class of human pathogens

The Human Brain: A Multimedia Tutorial For The Independent Learner

The Human Brain is a multimedia, interactive, computer-based tutorial on the structure and function of the human nervous system. In creating it, we aim to solve a number of problems, both subject specific and general. As a subject, the structure and function of the nervous system is difficult to teach using traditional methods and there is a lack of integration in the teaching of structure and function. More generally, we are concerned with the difficulties of both assessing student understanding of a particular subject and remedying any deficiencies when the student is learning independently. Finally, we hope to resolve the conflict between linear and explorative modes of presentation of material in a teaching system

Indicators of weed competition on Organic Winter Wheat

Organic winter wheat production is limited by climatic and agronomic factors, including weed competition. The incidence of weeds on yield limitation can be characterized through various early indicators to predict weed occurrence and competition. A network of 10 fields of organic winter wheat was implemented in the South East of France in 2005-2006. Results showed that weed density, dynamics and diversity are good indicators for weed occurrence and competition

THE ECONOMICS OF NON-GMO SEGREGATION AND IDENTITY PRESERVATION

We survey grain and soybean handlers and producers in the U.S. and EU to estimate costs of preserving the identities of GMO and non-GMO crops in marketing channels. We introduce our estimates into the IFPRI IMPACT model to simulate the effects of identity preservation on farm incomes and consumer well-being.Research and Development/Tech Change/Emerging Technologies,

The State of the Canon in Constitutional Law: Lessons from the Jurisprudence of John Marshall

Constitutional law has been an active battlefield as competing groups within the academy seek to deconstruct, reconstruct, and/or relegitimize the teaching and practice of law in the United States. Much of the rhetoric of the debate is couched in the language of rights. There is a danger that diminished attention to powers in the rhetoric and teaching of constitutional law may compromise sober and moderate constitutional reasoning. By reinvigorating reflection on powers-related issues, the legal profession can do its part to promote sobriety, and hence an added dose of prudence, in constitutional reflection and discourse by a democratic citizenry whose natural impulse is to make self-serving demands in the name of individual freedom and autonomy. In the constitutional reasoning and jurisprudence of John Marshall can be found considerable support for striking a balance between attention to powers and rights

A MODEL SYSTEM FOR THE CONCENTRATION OF REOVIRUS FROM AQUEOUS ENVIRONMENTS

A filter adsorption-elution method for the routine isolation of reovirus from model aqueous systems was developed. Reovirus was found to be stable within a pH range of 3 to 10, with a minimum loss of viability. A slight hydrogen ion excess minimized virus aggregation phenomena and promoted efficient adsorption of virus to filter surfaces. Adsorption of virus at pH 6.0 to all filters examined was enhanced by 50 mM MgCl(,2). The use of AlCl(,3) as an enhancing salt was contraindicated since reovirus was not recoverable from 0.5 mM AlCl(,3) solutions. Elution of virus was most effective when a 3% beef extract eluent was used. In the model system, reconcentration of eluates was achieved by flocculation of beef extract proteins at pH 3.5. Reconcentration of reovirus and several representative enteroviruses was also achieved by means of a hemocyanin-enriched fraction derived from Limulus polyphemus hemolymph