Amplification and analysis of human DNA present in mosquito bloodmeals

Abstract. DNA fingerprinting should permit the identification of individual human hosts of haematophagous arthropods, providing epidemi-ologically useful information, for example, the biting rates on different people and the impact of insecticide-impregnated bednets.
Investigations reported here demonstrate that it is possible to extract, amplify and fingerprint human DNA from the bloodmeals of individual female Anopheles gambiae mosquitoes kept at 24^oC for up to 10–15 h post-ingestion.     

A Cryomicroscopic Study of Cylindrocystis brebissonii De Bary and Two Species of Micrasterias Ralfs (Conjugatophyceae, Chiorophyta) during Freezing and Thawing

The changes in morphology of the unicellular algae Cylindrocystisbrebissonii and two species of Micrasterias during freezingand thawing were observed on a light microscope fitted witha temperature controlled stage. At slow rates of cooling extensiveshrinkage of the protoplast was observed. The response of thecell wall varied with cell-type. In C. brebissonii plasmolysiswas not observed and the cell wall and protoplast shrank together.In Micrasterias the cell wall did not contract and a distinctplasmolysis was observed. Following freezing to and thawingfrom –25?C cells of C. brebissonii were non-viable butremained osmotically responsive. Cooling at faster rates inducedintracellular ice formation in all cell-types. The criticalrate of cooling varied with cell-type and was determined bycell volume and suface area. Intracellular gas bubbles wereobserved during thawing following both rapid and slow cooling. Following cooling in dimethylsulphoxide cells of C. brebissoniiwere protected against freezing injury. The recovery on thawingfrom –196?C being determined by the rate of cooling, anoptimum rate of 1?C min^–1 was observed. During slow ratesof cooling (<2?C min^–1) cells remained unshrunken,at faster rates (10?C min^–1) the loss of cell viabilitywas related to osmotic shrinkage during cooling rather thanto nucleation of intracellular ice. Intracellular ice formationwas observed only following significantly faster rates of cooling(>20?C min^–1). Key words: Cylindrocystis, Micrasterias, cryomicroscopy, freezing injury     

Age at first breeding, philopatry and breeding site-fidelity in the Lapwing Vanellus vanellus

Breeding Lapwings Vanellus vanellus were studied in the Eden Valley (Cumbria) and in Teesdale (County Durham) between 1990 and 1992. A total of 300 adult Lapwings and 801 near-fledged young were uniquely colour-ringed. Breeding adults were highly site-faithful, almost always nesting in the same or an adjacent field in successive years. Second-year birds were less site-faithful, with more birds nesting in adjacent and other fields and fewer in the same field in successive years. In Teesdale, 74% of colour-ringed young Lapwings returned in their first or second year of life to within 5 km from where they hatched. In contrast, in the Eden Valley only 37% of young birds in their first or second year of life returned to within 5 km from where they hatched. From an analysis of British ringing recoveries in April and May, 61% of Lapwings were recovered within 10 km from where they were ringed as chicks. A further 11% were recovered more than 100 km from where they were ringed. Young Lapwings were highly philopatric, with 45% of males and 52% of females breeding in the same field or a field adjacent to where they hatched. The majority of Lapwings (67%) began breeding at 1 year old. Of the remaining birds, 27% bred for the first time when 2 years old and 6% for the first time in their third year of life. There was no difference between the sexes. Chicks hatching and subsequently fledging late in the season returned less frequently to the study areas in subsequent years than did chicks hatching earlier in the season.     

Shelf-life of stored asparagus is strongly related to post-harvest accumulated heat units

The effect of delay between harvest and hydrocooling, and of regimes of simulated air transport temperatures, on shelf-life of fresh asparagus were quantified. Shelf-life was strongly negatively correlated with the accumulated heat units experienced between harvest and post-transport handling. A 2-h delay in hydrocooling after harvest was similar to a 0.5°C higher temperature during a 2-day transit period in effect on shelf-life. It is essential for maximum shelf-life that asparagus be kept cold from the completion of hydrocooling until sale.     

Mating systems in the Lapwing Vanellus vanellus

The Lapwing Vanellus vanellus has traditionally been regarded as a monogamous, single brooded species, defending a single territory. Recent studies involving individually recognizable Lapwings have begun to challenge the ubiquity of these statements, with high frequencies of polygyny and the production of second broods being reported. Breeding Lapwings were studied in Upper Teesdale, County Durham, U.K., between 1993 and 1995, where both adults and chicks had been individually colour-ringed since 1990. A total of 90 territorial males and 64 females were intensively studied during the 3 years. Overall, 30% of territorial males had more than one mate in any year, with 19% more adult males than yearling males mating polygynously. On two occasions, polygynous males simultaneously defended two territories. Five females attempted to produce second broods, and one was polyandrous.