Broken houses: Science and development in the African Savannahs

In many developing countries people and livestock suffer from preventable or curable diseases, and their agriculture is vulnerable to natural disasters. A considerable amount of technical aid is directed at alleviating these problems using modern science and technology, and yet most of these efforts either fail or even leave peasants and pastoralists worse off than before. In this paper we consider some of the problems that arise in relation to development projects, focusing our attention on the savannah regions of Africa and, in particular, on the control of tsetse flies, which are the vectors of the African trypanosomiases, called nagana in cattle and sleeping sickness in people. We present a detailed case study of a project designed to enable a Maasai community in Kenya to carry out their own tsetse fly control. We examine the complex set of relationships and power structures that mediate the actions of the players in development: scientists, local communities, governmental and nongovernmental institutions, and development agencies. The purpose of this paper is not to present solutions to complex and difficult problems but rather to raise questions that should provide a framework for a debate concerning the role of science and technology in the development process.Brian Williams in the director of an epidemiology unit that carries out research into the health and safety of South African mine workers. He has previously worked on the control of tsetse flies and trypanosomiasis in Kenya and on modelling vector borne diseases at Oxford University and the London School of Hygiene and Tropical medicine.     

Pertussis toxin-sensitive pathway in the stimulation of c-myc expression and DNA synthesis by bombesin

The bombesin-like peptides are potent mitogens for Swiss 3T3 fibroblasts, human bronchial epithelial cells, and cells isolated from small cell carcinoma of the lung. The mechanism of signal transduction in the proliferative response to bombesin was investigated by studying the effect of Bordetella pertussis toxin on bombesin-stimulated mitogenesis. At nanomolar concentrations, bombesin increased levels of c-myc messenger RNA and stimulated DNA synthesis in Swiss 3T3 cells. Treatment of the cells with pertussis toxin (5 nanograms per milliliter) completely blocked bombesin-enhanced c-myc expression and eliminated bombesin-stimulated DNA synthesis. This treatment had essentially no effect on the mitogenic responses to either platelet-derived growth factor or phorbol 12,13-dibutyrate. These results suggest that the mitogenic actions of bombesin-like growth factors are mediated through a pertussis toxin-sensitive guanine nucleotide-binding protein. Furthermore they indicate that bombesin-like growth factors act through pathways that are different from those activated by platelet-derived growth factor.     

Neuronal cell Thy-1 glycoprotein: homology with immunoglobulin

The amino acid sequences of mouse brain Thy-1 glycoproteins are shown to be homologous to those of variable-region immunoglobulin domains. There is also good homology with constant domains and beta 2-microglobulin; overall the results suggest that Thy-1 may be like the primordial immunoglobulin domain. Preliminary evidence for an invertebrate Thy-1 homolog supports this possibility.     

Insects as selective agents on plant vegetative morphology: egg mimicry reduces egg laying by butterflies

Experiments show that Heliconius butterflies are less likely to oviposit on host plants that possess eggs or egglike plant structures. These egg mimics are an unambiguous example of a plant trait evolved in response to a host-restricted group of insect herbivores.     

Auditory responses in avian vocal motor neurons: a motor theory for song perception in birds

The hypoglossal motor neurons that innervate the vocal organ (syrinx) of the male zebra finch show a selective, long-latency (50-millisecond) response to sound. This response is eliminated by lesions to forebrain song-control nuclei. Different song syllables elicit a response from different syringeal motor neurons. Conspecific vocalizations may therefore be perceived as members of a set of vocal gestures and thus distinct from other environmental sounds. This hypothesis is an avian parallel to the motor theory of speech perception in humans.