Radiation biology of mosquitoes

There is currently renewed interest in assessing the feasibility of the sterile insect technique (SIT) to control African malaria vectors in designated areas. The SIT relies on the sterilization of males before mass release, with sterilization currently being achieved through the use of ionizing radiation. This paper reviews previous work on radiation sterilization of Anopheles mosquitoes. In general, the pupal stage was irradiated due to ease of handling compared to the adult stage. The dose-response curve between the induced sterility and log (dose) was shown to be sigmoid, and there was a marked species difference in radiation sensitivity. Mating competitiveness studies have generally been performed under laboratory conditions. The competitiveness of males irradiated at high doses was relatively poor, but with increasing ratios of sterile males, egg hatch could be lowered effectively. Males irradiated as pupae had a lower competitiveness compared to males irradiated as adults, but the use of partially-sterilizing doses has not been studied extensively. Methods to reduce somatic damage during the irradiation process as well as the use of other agents or techniques to induce sterility are discussed. It is concluded that the optimal radiation dose chosen for insects that are to be released during an SIT programme should ensure a balance between induced sterility of males and their field competitiveness, with competitiveness being determined under (semi-) field conditions. Self-contained ⁶⁰Co research irradiators remain the most practical irradiators but these are likely to be replaced in the future by a new generation of high output X ray irradiators.     

The Economic Importance of Communal Net Hunting Among the BaAka of the Central African Republic

This article examines current net hunting practice by BaAka Pygmies of central Africa. In terms of time allocation, net hunting remains the single most important activity for the BaAka, But net hunting is only one in a range of subsistence and economic activities among which individuals switch on a daily basis. Returns from net hunting are roughly equivalent to those from competing activities. Several factors encourage the decline of net hunting and its replacement with snare hunting: enforcement of park regulations, higher individual returns to snare hunting, and greater involvement in formal employment and agriculture. However, net hunting has not been abandoned completely for several reasons: the local market demand for bushmeat is growing, numerous forest products besides meat are collected on net hunts, and economic alternatives remain irregular and unreliable.     

Ozone depuration of Vibrio vulnificus from the southern quahog clam, Mercenaria campechiensis

Southern quahog clams, Mercenaria campechiensis, were dosed with Vibrio vulnificus and placed in a pilot-scale depuration system using ozonated recirculated artificial seawater. Twenty-four hours of treatment with ozone-treated recirculating artificial seawater reduced the numbers of V. vulnificus in the shellfish meats by an average of 2 log units when compared to natural die-off in control clams. The oxidant levels (up to 3 mg/liter) did not adversely affect shellfish pumping during the depuration process.     

The dental morphology of Pima Indians

Fourteen morphologic crown traits were observed in a sample of 1528 Pima Indians of south-central Arizona. Pima dentitions are characterized by high frequencies of shoveling, incisor winging, the hypocone, the lower canine distal accessory ridge, cusp 6, and the protostylid. They exhibit low frequencies of the metaconule and lower premolar multiple lingual cusps and moderate frequencies of the canine tubercle, Carabelli's trait, cusp 7, and lower second molars with four cusps and X groove patterns. When Pima crown trait frequencies were compared to those of 13 Southwest Indian samples, their closest affinities were to other Uto-Aztecan groups, the Papago and Hopi. The Pima are most divergent from Athapaskans and are also clearly removed from Yuman speaking groups and the Zuni. In general, the pattern of dental morphologic variation in the Southwest corresponds closely to linguistic divisions.     

Noradrenaline as a putative neurotransmitter mediating hypotension—induced FOs—like immunoreactivity in the supraoptic nucleus of the rat

Hemorrhage or hypotension induces extensive Fos-like immunoreactivity in the magnocellular neurosecretory cells in the supraoptic nucleus of the hypothalamus in rat,especially in the vasopressin neurons.The present study was to explore the neurotransmitter mediating this effect,Microinfusion of the alpha-adrenergic blocker into the supraoptic nucleus reduced the hypotension-induced FOs.whereas beta-antagonist did not affect it significantly.Alaha1-and alpha2-antagonist,prazosin and yohimbine,both reduced the Fos-Positive cell counts.However,the effective dosage of yohimbine was much larger,Alpha1-agonist,methoxamine,induced abundant Fos-like immunoreactivity in the vasopressin cells in this nucleus,while beta-and alpha2-agonist did not elicit such effect.Administration of the noradrenergic re-uptake inhibitor desipramine,to this nucleus to locally accumulate the spontaneously released noradrenaline from the nerve terminals also induced Fos expression,mostly in the vasopressin cells.