There are several sources of fluctuations in gene expression. Here we study the effects of time-dependent DNA replication, itself a tightly controlled process, on noise in mRNA levels. Stochastic simulations of constitutive and regulated gene expression are used to analyze the time-averaged mean and variation in each case. The simulations demonstrate that to capture mRNA distributions correctly...

We examine the possibility of fermion mass generation in 2+1–dimensional gauge theory from the current algebra point of view. In our approach the critical behavior is governed by the fluctuations of pions which are the Goldstone bosons for chiral symmetry breaking. Our analysis supports the existence of an upper critical NF and exhibits the explicit form of the gap equation as well as the form ...

DNA compaction in a bacterial cell is in part carried out by entropic (depletion) forces induced by "free" proteins or crowding particles in the cytoplasm. Indeed, recent in vitro experiments highlight these effects by showing that they alone can condense the E. coli chromosome to its in vivo size. Using molecular dynamics simulations and a theoretical approach, we study how a flexible chain mo...

To facilitate the search for candidate telomerase inhibitors, we exploited the database of the disease-oriented screening program (DOS) available in our facility by using COMPARE analysis. In primary and arbitrary screening, we were able to identify the alkaloid berberine as a moderate inhibitor with 50% inhibition at approximately 35 microM. Using this alkaloid as a seed compound in COMPARE re...

How and why female somatic X-chromosome inactivation (XCI) evolved in mammals remains poorly understood. It has been proposed that XCI is a dosage-compensation mechanism that evolved to equalize expression levels of X-linked genes in females (2X) and males (1X), with a prior twofold increase in expression of X-linked genes in both sexes ("Ohno's hypothesis"). Whereas the parity of X chromosome ...

Telomeres are associated with the nuclear matrix and are thought to be heterochromatic. We show here that in human cells the overexpression of green fluorescent protein-tagged heterochromatin protein 1 (GFP-HP1) or nontagged HP1 isoforms HP1(Hsalpha) or HP1(Hsbeta), but not HP1(Hsgamma), results in decreased association of a catalytic unit of telomerase (hTERT) with telomeres. However, reductio...

Dosage compensation in flies involves doubling the transcription of genes on the single male X chromosome to match the combined expression level of the two female X chromosomes. Crucial for this activation is the acetylation of histone H4 by the histone acetyltransferase (HAT) MOF. In male cells, MOF resides in a complex (dosage compensation complex, DCC) with MSL proteins and noncoding roX RNA...

The methodology and results of epidemiological studies of the effects of preconception diagnostic x-rays of the abdomen on chromosome segregation in humans are described. Many studies have been conducted in a number of different countries. The vast majority show the same positive, though not significant, trend to increased nondisjunction among the offspring of irradiated women. The results of t...

Interspecific hybridisation and polyploidy are recognized as the most important sources of evolution and domestication of flowering plants. In ornamental plant breeding these phenomena go hand in hand and can be observed in the breeding history of many ornamental crops (Rosa, Chrysanthemum, Gladiolus, Alstroemeria, Lilium, orchids etc). With lily as model crop techniques developed for overcomin...

Two prominent mangrove species of Fiji, Rhizophora mangle, Linn. Rhizophora stylosa Griff and their puative hyubrid (R x selala) were analysed for chromosome number and pairing. Both parental species and their hybrid possess a diploid number of (2n) = 36 chromosomes. Regular 18 bivalents were observed in two species but the hybrid lacked proper chromosome pairing during meiosis. Analysis of tet...