Meiotic transmission of an in vitro-assembled autonomous maize minichromosome.

Autonomous chromosomes are generated in yeast (yeast artificial chromosomes) and human fibrosarcoma cells (human artificial chromosomes) by introducing purified DNA fragments that nucleate a kinetochore, replicate, and segregate to daughter cells. These autonomous minichromosomes are convenient for manipulating and delivering DNA segments containing multiple genes. In contrast, commercial production of transgenic crops relies on methods that integrate one or a few genes into host chromosomes; extensive screening to identify insertions with the desired expression level, copy number, structure, and genomic location; and long breeding programs to produce varieties that carry multiple transgenes.

The Search for Novel Malaria Transmission-blocking Targets in the Mosquito Midgut.

The need for new malaria control strategies has led to increased efforts to understand more clearly the mosquito stages of Plasmodium. The absolute requirement of gamete maturation and fertilization, transformation of sedentary zygote to motile ookinete, ookinete interaction and invasion of gut epithelium, and the survival of the mosquito against immune attack suggest that numerous unidentified targets exist, which could be modified to achieve transmission-blocking of malaria. In the search for new transmission-blocking targets in the mosquito gut, Mohammed Shahabuddin, Stéphane Cociancich and Helge Zieler here summarize recent studies to identify the cellular and biochemical factors that affect the malaria parasite's development; in particular, factors influencing the early development of Plasmodium, receptor-mediated interactions between the parasite and the mosquito midgut, and the gut-associated immune responses directed against Plasmodium.

Seasonal malaria transmission and variation of anopheline density in two distinct endemic areas in Brazilian Amazonia.

Studies on seasonal anopheline fauna variation were performed in two distinct settlements in the State of Rondônia, Brazil: one at the Madeira River banks (Portuchuelo) with stable native Amazonian population; the other at an inland lumber-extracting farm (Urupá) in dry land, in which adults are mostly migrants. During a 6-yr period (1994-2000), 8,638 adult anophelines were collected: 2,684 in Urupá and 5,954 in Portuchuelo. Anopheles darlingi represented >95% of total mosquitoes caught.

Bee venom phospholipase inhibits malaria parasite development in transgenic mosquitoes.

Malaria kills millions of people every year, and new control measures are urgently needed. The recent demonstration that (effector) genes can be introduced into the mosquito germ line to diminish their ability to transmit the malaria parasite offers new hope toward the fight of the disease (Ito, J., Ghosh, A.

Intron-dependent stimulation of marker gene expression in cultured insect cells.

We tested in a systematic fashion the effect of an intron on the level of luciferase expression in cultured C6/36 Aedes albopictus cells. The intron was inserted in both orientations, upstream and downstream of the luciferase coding region in two different luciferase expression vectors. The two parental luciferase expression vectors differed only in their promoters, one containing the Drosophila melanogaster actin5C promoter and the other the Autographa californica nuclear polyhedrosis virus hr5/ie1 enhancer/promoter.