An answer to a complex problem: cloning the mouse t-complex responder

The t-complex is maintained in wild mouse populations by its high transmission (up to 99%) from heterozygous males and provides an example of ``meiotic drive'. Its molecular basis has remained obscure despite long and intensive study. In a major advance, the t-complex responder gene, thought to be the key gene on which several distorters act, has now been cloned. Received: 14 April 2000 / Accepted: 4 May 2000     

A teleosemantic approach to information in the brain

The brain is often taken to be a paradigmatic example of a signaling system with semantic and representational properties, in which neurons are senders and receivers of information carried in action potentials. A closer look at this picture shows that it is not as appealing as it might initially seem in explaining the function of the brain. Working from several sender-receiver models within the teleosemantic framework, I will first argue that two requirements must be met for a system to support genuine semantic information: 1. The receiver must be competent—that is, it must be able to extract rewards from its environment on the basis of the signals that it receives. 2. The receiver must have some flexibility of response relative to the signal received. In the second part of the paper, this initial framework will be applied to neural processes, pointing to the surprising conclusion that signaling at the single-neuron level is only weakly semantic at best. Contrary to received views, neurons will have little or no access to semantic information (though their patterns of activity may carry plenty of quantitative, correlational information) about the world outside the organism. Genuine representation of the world requires an organism-level receiver of semantic information, to which any particular set of neurons makes only a small contribution.     

The hypoxic core: a possible answer to the cancer paradox

There are many differences, at all levels of organization, between cancerous and normal cells. Two of these (oxygen delivery and glucose metabolism) are related and manifest as low intercellular oxygen tensions (pO(2)) and a glycolytic metabolic profile in tumours and/or cancer cells. It is becoming increasingly apparent that these characteristics of cancer combine to enhance both the survival and aggressiveness of cancer cells, and that they can adversely impact on some forms of treatment. But they are also exploited in current strategies of detection and monitoring of cancers. These are therefore characteristics with important implications for the crucial balance between the aggression and growth characteristics of a tumour, and our ability to detect and treat it. The interactions and the hierarchy of events leading to these manifestations are complex, not fully understood, and involve a pivotal and intriguing paradox. This paradox results in a seemingly contradictory state in which the most dangerous tumours are those that are the most hypoxic, but also those that are the most angiogenic. This review is a synthesis of the available data into a feasible hypothesis which offers a possible resolution of this paradox and provides a testable paradigm for tumour behaviour.     

FiRe and microarrays: a fast answer to burning questions

FiRe is a user-friendly Excel macro designed to survey microarray data rapidly. This software interactively assembles data from different experiments and produces lists of candidate genes according to patterns of gene expression. Furthermore, macros bundled with FiRe can compare lists of genes, merge information from different spreadsheets, link candidates to information available from web-based databases, and produce heat-maps for easy visualization of microarray data. FiRe is freely available at http://www.unifr.ch/plantbio/FiRe/main.html .     

Biology of cancer: some questions to answer

Though great advances in cancer biology have taken place through these years, some fundamental questions are still to be explained. Some observations in this regard are discussed in the present paper. In the course of experimental studies on hormonal stimulation of target cells, it was observed that goat granulosa cells showed differential proliferative response to sustained stimulation by oLH and hCG in culture. oLH caused cells to proliferate whereas hCG failed to stimulate the cells though both the gonadotropins have common receptors on the target cell. Further studies might throw some light on the mechanism of signal transduction in cell biology and neoplasia. A question is also posed as to how to interpret thermodynamically the sustained growth of cancer vis-a-vis the host.     

Maximization of pleasure, the answer to a conflict of motivations

An experiment has been set up to explore the hypothesis according to which behaviour is determined by the trend to maximize pleasure. Twelve subjects were placed individually in a situation of conflict where the pleasure of playing a videogame clashed with the increasing discomfort of a cold environment. The time lapse tolerated could be predicted from the algebraic sum of the rating of displeasure aroused by the cold environment and the rating of pleasure aroused by the videogame, obtained in other sessions. This result supports the working hypothesis and allows to conclude that pleasure is the common currency of tradeoffs among various motivations.     

未能止住草场的扩张

<正>草场实在不行了,牛羊太多,吃得太厉害,让草根本没时间长出来,那时起,队里决定要赶着牛羊上山了。随着谈话的逐渐深入,我们发现,这个"联户制度"既不只是合用草场联合放牧那么简单,也不是"只针对水源紧张才采取的行动"那么单纯,     

Bacterial pathogenesis: the answer to virulence is in the pore.

A wide variety of Gram-negative bacterial pathogens use a 'type III' protein secretion system to deliver bacterial virulence factors into host cells. Recent results suggest that Gram-positive pathogens may employ similar methods to deliver virulence factors into host cells.     

Plant synthetic biology: One answer to global challenges

正In times of climate change, population growth and resource depletion, the future well-being of mankind will greatly depend on the ability to breed/engineer crop plants for high yield, low input and high quality.Based on the evaluation of historical yield increases, it seems that yield of major grain crops, such as rice or