Transformed root cultures for biotechnology

This review is concerned with the application of hairy roots, i.e. plant roots formed from plant cells after transformation by Agrobacterium rhizogenes for the production of bioactive compounds. Transformed root cultures have been established from numerous species of dicotyledonous plants. The plants, as well as the main products accumulated in hairy root cultures derived from these plants, are listed in this paper. Data are presented on novel compounds, hitherto detected only in transformed roots but not occurring in the corresponding intact plants. The possible use of hairy root cultures for the over-production of secondary metabolites and biotransformation of chemicals is discussed. In order to enhance the productivity of hairy root cultures, various methods have been derived, and optimized procedures are proposed. They include selection of high-producing clones, elicitation, composition of growth media, culture conditions and genetic approach. Hairy roots usually store secondary metabolites in vacuoles inside the cells. Therefore, several methods have been used to increase the amount of products released into the medium. Unfortunately, no general procedure is known that works in all cases, and the excretion behaviour of hairy root cultures varies from one species to another and even within one species from one clone to another. Special attention is given to the cultivation methods and bioreactor systems for hairy root cultures. Hairy roots are cultivated usually in shake flasks; however, shake flask culture is not suitable for the complex optimization and continuous control of the culture conditions. In this paper, we are going to present bioreactors proposed for the cultivation of hairy roots under more or less controlled conditions. Modifications of typical bacterial bioreactors, i.e. stirred tanks, airlift loop reactors and other constructions, are presented. A very special type of bioreactor providing good conditions for loose root mass multiplication without oxygen or substrate limitations, is the mist bioreactor. Nowadays, it is practically impossible to select the one best bioreactor type for hairy root culture.     

Fighting for survival.

The political crisis in Haiti has had a severe impact on the health of the population. Mortality among Haitians is 13 per 1000, much higher than the Latin American rate of seven per 1000, and the incidence of AIDS, tuberculosis, and malnourishment is increasing among children. Although food and medicine are exempt, United Nations sanctions have had a negative impact on most of the population. In particular the embargo on fuel has limited most people''s access to health care. The difficulties of distributing aid and health care without softening the embargo on fuel are immense, and the health of Haitians is not likely to improve until the political crisis is resolved.     

Fighting for food: a dynamic version of the Hawk-Dove game

Summary The Hawk-Dove game (Maynard Smith, 1982) has been used to analyse conflicts over resources such as food. At the evolutionarily stable strategy (ESS), either a proportionp* of animals always play Hawk, or each animal has a probabilityp* of playing Hawk. We modify the standard Hawk-Dove game to include a state variable,x, that represents the animal's level of energy reserves. A strategy is now a rule for choosing an action as a function ofx and time of day. We consider a non-reproductive period and adopt the criterion of minimizing mortality over this period. We find the ESS, which has the form play Hawk if reserves are belowc* (t) at timet, otherwise play Dove. This ESS is very different from the ESS in the standard Hawk-Dove game. It is a pure ESS that depends on the animal's state and on time. Furthermore, it is characterized by the strong condition that any single mutant that does not adopt the ESS suffers a reduction in fitness. The standard Hawk-Dove game assumes pay-offs that are related to fitness; our approach starts from a definition of fitness and derives the pay-offs in the process of finding the ESS. When the environment becomes worse (e.g. food becomes less reliable or energy expenditure increases) the ESS changes in such a way as to increase the proportion of animals that will play Hawk.     

Fighting to stay: the role of sibling rivalry for delayed dispersal

In many bird species with delayed dispersal, siblings differ in how long they postpone independence. Some offspring remain with their parents for a year or more and generally forego personal reproduction, while other siblings disperse in the first summer of life. We studied the basis for this variation by following dispersal among newly fledged Siberian jays, Perisoreus infaustus, carrying radiotransmitters. Postponed dispersal was the preferred option. Sibling rivalry preceded dispersal, and the larger and socially dominant siblings within broods were more likely to stay. No sex effect was found: males and females were just as likely to delay dispersal. This role of sibling rivalry shows that models explaining delayed dispersal based on ecological constraints outside the natal territory are too simplistic. The process of within-brood competition in determining which individuals disperse and which ones delay dispersal indicates that there are benefits to be gained from remaining in the natal territory. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

A Mismatch between the Perceived Fighting Signal and Fighting Ability Reveals Survival and Physiological Costs for Bearers

Signals of fighting indicate an animal''s intention to attack and so they serve to prevent costly aggressive encounters. However, according to theory, a signal that is different in design (i.e. a novel signal) but that fails to inform fighting intentions will result in negative fitness consequences for the bearer. In the present study we used males of the territorial damselfly Hetaerina americana, which have a red wing spot during territory defense that has evolved as a signal of fighting ability. By producing a novel signal (covering the red spot with blue ink) in territory owners, we investigated: a) the behavioral responses by conspecific males; b) survival cost and c) three physiological mediators of impaired survival: muscular fat reserves, muscle mass and immune ability. We predicted that males with the novel signal would be attacked more often by conspecifics as the former would fail to convey fighting ability and intentions adequately. This will result in lower survival and physiological condition for the novel signal bearers. We found that, compared to control males (males whose red spot was not changed), experimental males had reduced survival, were less able to hold a territory, and had a reduced muscle mass. It seems that spot modified males were not able to effectively communicate their territory tenancy, which may explain why they lost their defended sites. Our results provide support for theoretical models that a novel signal that fails to informing fighting ability may lead to a fitness cost for bearers.     

Purine and Pyrimidine Metabolism: a Firm Basis for a Transformed Society

Purines and pyrimidines form the backbone of DNA and RNA. Hence, modification of purine and pyrimidine metabolism can have serious effects on normal functioning of a subject. These aspects formed the main topics for an International and a European Series of meetings, dedicated to the metabolism in man. In order to streamline the organization of these meetings the European Society was transformed to an International society: the Purine and Pyrimidine Society (www.ppsociety.org). This special issue of Nucleosides, Nucleotides, and, Nucleic, Acids highlights the last European meeting in Prague, focusing on inborn errors, cardiac diseases, inflammatory diseases, rheumatology, haematology, cancer, virology, genetic polymorphism, specific methodology, and, of course, metabolism. The meeting in Chicago in 2007 will be the first meeting of the Purine and Pyrimidine Society.     

Media framing of the Cayman Turtle Farm: Implications for conservation conflicts

Conflicts over natural resource use and management often arise where groups have different goals or priorities. The media can play an important dual role in these conflicts; article content might offer insights about public opinion, whilst media may shape debates and how issues are perceived by the public and decision-makers. Wildlife farming is a contentious conservation tool attracting the attention of worldwide media, and associated conflicts among different interest groups may undermine its applicability. We investigated the media’s portrayal of the Cayman Turtle Farm (CTF), a facility in the Cayman Islands which breeds green sea turtles (Chelonia mydas) for human consumption, to investigate how the media presents information about wildlife farming (i.e. framing), consider its potential roles influencing conflicts and explore how it can be used for conservation conflict management. Content analysis was used to compare framing, article valence, and stakeholder representation in 634 newspaper articles from the international and local media. These media stories were framed in terms of: tourism, conflict, conservation, culture/community, management, and utilisation. International articles most often described CTF as a tourism facility. However, during a media campaign by an international animal welfare group, CTF was also often depicted as a source of controversy. Trade in turtle products was mostly debated in older articles. Local media mainly had a financial focus. Conflict framing was associated with a negative article valence, and conflict framed articles were significantly more likely to contain no conservation information. Mentions of environmental interest groups were significantly associated with negative articles, whereas academics were significantly more likely to be mentioned in positive articles. Conservationists must consider stakeholder objectives from the outset of interventions and be aware of the multiple roles the media might play. Media analysis and effectively harnessing the potential of media outlets should be considered as tools for managing conservation conflicts.     

Fighting neurodegeneration with rapamycin: mechanistic insights

A growing number of studies point to rapamycin as a pharmacological compound that is able to provide neuroprotection in several experimental models of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease and spinocerebellar ataxia type 3. In addition, rapamycin exerts strong anti-ageing effects in several species, including mammals. By inhibiting the activity of mammalian target of rapamycin (mTOR), rapamycin influences a variety of essential cellular processes, such as cell growth and proliferation, protein synthesis and autophagy. Here, we review the molecular mechanisms underlying the neuroprotective effects of rapamycin and discuss the therapeutic potential of this compound for neurodegenerative diseases.     

Fighting cancer in the information age: the role of Internet

Cancer is a major health problem worldwide which is likely to assume alarming proportions in the next two decades. Communication and information have increasingly been considered important in helping people to cope with cancer. The arrival of Internet offers the opportunity to fundamentally reinvent medicine and health care delivery. Medical professionals can now use the Internet for continuing medical education, access latest medical information, for fast confirmation of diagnosis, exchange opinion on treatment strategies and in palliative care. Internet can provide cost-effective and timely ways to deliver a complex mix of interesting and high-quality information and expertise to cancer patients. Patients can also independently search the Internet to know about their illness and treatment options. However, of concern is the quality of information that is available in the 'Net'. Some Internet sites may contain erroneous information on cancer and can pose serious problems. There are also many good sites, which provide quality information on cancer for medical professionals, researchers and patients. This article focuses on how the Internet will aid us in fight against cancer.