Anti-apoptotic mechanisms of HIV: lessons and novel approaches to curing HIV

Past efforts at curing infection with the human immunodeficiency virus (HIV) have been blocked by the resistance of some infected cells to viral cytopathic effects and the associated development of a latent viral reservoir. Furthermore, current efforts to clear the viral reservoir by means of reactivating latent virus are hampered by the lack of cell death in the newly productively infected cells. The purpose of this review is to describe the many anti-apoptotic mechanisms of HIV, as well as the current limitations in the field. Only by understanding how infected cells avoid HIV-induced cell death can an effective strategy to kill infected cells be developed.     

Maize HapMap2 identifies extant variation from a genome in flux

Whereas breeders have exploited diversity in maize for yield improvements, there has been limited progress in using beneficial alleles in undomesticated varieties. Characterizing standing variation in this complex genome has been challenging, with only a small fraction of it described to date. Using a population genetics scoring model, we identified 55 million SNPs in 103 lines across pre-domestication and domesticated Zea mays varieties, including a representative from the sister genus Tripsacum. We find that structural variations are pervasive in the Z. mays genome and are enriched at loci associated with important traits. By investigating the drivers of genome size variation, we find that the larger Tripsacum genome can be explained by transposable element abundance rather than an allopolyploid origin. In contrast, intraspecies genome size variation seems to be controlled by chromosomal knob content. There is tremendous overlap in key gene content in maize and Tripsacum, suggesting that adaptations from Tripsacum (for example, perennialism and frost and drought tolerance) can likely be integrated into maize.     

Permeability of fresh and stored human erythrocytes to glycerol and its acylated derivatives

Summary The effect of copper ions on the permeation of glycerol and its mono-, di-, and triacetate derivatives was studied in fresh and stored erythrocytes. Permeability was unchanged with storage. Acylated glycerols permeate the cells mainly by non-facilitated mechanism, as their transport is almost unaffected by copper ions.Portions of this work were included in the graduate thesis of Dr. Yaeger in partial fulfillment of the requirements for the M. D. degree.Acknowledgement. We thank Mrs Dalia Mazor for expert technical assistance.     

Two methods of catecholamine depletion in kitten visual cortex yield different effects on plasticity

As first clearly demonstrated by the experiments of Wiesel and Hubel, the developing visual cortex is exquisitely sensitive to sensory deprivation. Temporary closure of one eye of a kitten during a critical period that extends from 3 weeks to 3 months of age results in a dramatic cortical reorganization such that most neurones, originally binocularly driven, are dominated exclusively by the open eye. Recently, attention has been directed to chemical factors which may influence the degree of plasticity during the critical period. The work of Kasamatsu and pettigrew suggests that cortical catecholamines, especially noradrenaline (NA), are essential for the normal plastic response to visual deprivation. In an effort to clarify the role of NA in visual cortical plasticity, we have monocularly deprived kittens whose cortex had been depleted of catecholamines by the neurotoxin 6-hydroxydopamine (6-OHDA). We used two strategies to deplete cortical NA: the first, pioneered by Kasamatsu el al., utilized osmotic minipumps to deliver 6-OHDA to visual cortex; the second involved systemic neonatal injections of 6-OHDA, a technique which has proved effective in rodents. We found, using high-pressure liquid chromatography (HPLC), that both techniques produced a substantial reduction in the level of cortical NA. However, single unit recording in area 17 revealed that the plastic response to monocular deprivation (MD) was only diminished in the kittens depleted by minipump.