position effect variegation (in which the probability of Epigenetic effects have often enough been viewed as inactivation of a gene translocated to a position near verging on the mystical. It is a paradox of conventional heterochromatin decreases with its distance from hetgenetics that two alleles can have the same genetic erochromatin). One of the characteristics of a state that sequence but s...

Dipteran insects show a wide range of species-specific mating positions. Interspecific transitions from one position to another may reflect sexual or natural selection, or be pleiotropic consequences of other genetic changes. Like many cyclorrhaphan flies, Drosophila species mate with the male on the back of the female, positioned centrally. Mechanosensory sensilla on the male genitalia of thre...

We have used 2-aminopurine (2AP) as a fluorescent probe in the template strand of a 13/20mer primer/template (D) to detect deoxynucleoside triphosphates (N)-dependent conformational changes exhibited by RB69 DNA polymerase (ED) complexes. The rates and amplitudes of fluorescence quenching depend hyperbolically on the [dTTP] when a dideoxy-primer/template (ddP/T) with 2AP as the templating base ...

The structure of the genetic code implies strict Watson-Crick base pairing in the first two codon positions, while the third position is known to be degenerate, thus allowing wobble base pairing. Recent crystal structures of near-cognate tRNAs accommodated into the ribosomal A-site, however, show canonical geometry even with first and second position mismatches. This immediately raises the ques...

Bastiaanse, Koekkoek And Van Zonneveld (2003) hypothesized that individuals with Broca’s aphasia have problems with sentences in which the verb and its arguments are not in their base position. The present study is meant to test this hypothesis with the help of verbs with alternating transitivity: transitive: the boy breaks the glass; intransitive or unaccusative: the glass breaks. Superficiall...

Transfer of alanine from Escherichia coli alanyl-tRNA synthetase (AlaRS) to RNA minihelices that mimic the amino acid acceptor stem of tRNA(Ala) has been shown, by analysis of variant minihelix aminoacylation activities, to involve a transition state sensitive to changes in the 'discriminator' base at position 73. Solution NMR has indicated that this single-stranded nucleotide is predominantly ...

The ability to identify and localize our own limbs is crucial for survival. Indeed, the majority of our interactions with objects occur within the space surrounding the hands. In non-human primates, neurons in the posterior parietal and premotor cortices dynamically represent the space near the upper limbs in hand-centered coordinates. Neuronal populations selective for the space near the hand ...

Good methods are needed to specify, test, and debug material-handling control logic. This article surveys a number of representative methods for defining and describing control algorithms for programmable materialhandling equipment used in flexible manufacturing systems. The methods are evaluated with regard to their suitability for communication between people and as bases for interfaces to au...

Topoisomerase 1 (Top1) enzymes regulate DNA superhelicity by forming covalent cleavage complexes that undergo controlled rotation. Substitution of nucleoside analogs at the +1 position of the DNA duplex relative to the Top1 cleavage site inhibits DNA religation. The reduced efficiency for Top1-mediated religation contributes to the anticancer activity of widely used anticancer drugs including f...

Three glutamine tRNA isoacceptors are known in Tetrahymena thermophila. One of these has the anticodon UmUG which reads the two normal glutamine codons CAA and CAG, whereas the two others with CUA and UmUA anticodons recognize UAG and UAA, respectively, which serve as termination codons in other organisms. We have employed these tRNA(Gln)-isoacceptors as tools for studying unconventional base i...