Chemoattraction of Vibrio fischeri to serine, nucleosides, and N-acetylneuraminic acid, a component of squid light-organ mucus.

Newly hatched juveniles of the Hawaiian squid Euprymna scolopes rapidly become colonized by the bioluminescent marine bacterium Vibrio fischeri. Motility is required to establish the symbiotic colonization, but the role of chemotaxis is unknown. In this study we analyzed chemotaxis of V.

Modulation of CRP-dependent transcription at the Escherichia coli acsP2 promoter by nucleoprotein complexes: anti-activation by the nucleoid proteins FIS and IHF.

acs encodes acetyl-coenzyme A synthetase, a high-affinity enzyme that allows cells to scavenge for acetate during carbon starvation. CRP activates acs transcription by binding tandem DNA sites located upstream of the major promoter, acsP2. Here, we used electrophoretic mobility shift assays and DNase I footprint analyses to demonstrate that the nucleoid proteins FIS and IHF each bind multiple sites within the acs regulatory region, that FIS competes successfully with CRP for binding to their overlapping and neighbouring sites and that IHF binds independently of either FIS or CRP.

Creatine phosphate kinase elevations signaling muscle damage following exposures to anticholinesterases: 2 sentinel patients.

In this study, the authors describe 2 patients who experienced confirmed exposures to anticholinesterases that commenced in the 1970s. Subsequently, elevations in creatine phosphate kinase (CPK) were initially detected more than a decade following the first acute exposure. Beginning in the early 1980s, the patients suffered from progressive generalized muscle weakness, chronic fatigue, myopathy, neuropathy, and severe neurobehavioral impairments.

Intensive pre-Incan metallurgy recorded by lake sediments from the Bolivian Andes.

The history of pre-Columbian metallurgy in South America is incomplete because looting of metal artifacts has been pervasive. Here, we reconstruct a millennium of metallurgical activity in southern Bolivia using the stratigraphy of metals associated with smelting (Pb, Sb, Bi, Ag, Sn) from lake sediments deposited near the major silver deposit of Cerro Rico de Potosí. Pronounced metal enrichment events coincide with the terminal stages of Tiwanaku culture (1000 to 1200 A.

Cyclic AMP receptor protein-dependent activation of the Escherichia coli acsP2 promoter by a synergistic class III mechanism.

The cyclic AMP receptor protein (CRP) activates transcription of the Escherichia coli acs gene, which encodes an acetate-scavenging enzyme required for fitness during periods of carbon starvation. Two promoters direct transcription of acs, the distal acsP1 and the proximal acsP2. In this study, we demonstrated that acsP2 can function as the major promoter and showed by in vitro studies that CRP facilitates transcription by "focusing" RNA polymerase to acsP2.

Evidence that acetyl phosphate functions as a global signal during biofilm development.

We used DNA macroarray analysis to identify genes that respond to the status of the intracellular acetyl phosphate (acP) pool. Genes whose expression correlated negatively with the ability to synthesize acP (i.e.

Making decisions about hazardous waste remediation when even considering a remediation technology is controversial.

This paper investigates the circumstances under which proposed hazardous waste remediation technologies are socially acceptable, that is, considered seriously as options in a public arena. First, it summarizes a conceptual framework that guides investigation and interpretation of site-specific remediation decision-making. Second, it describes an initial application of that framework to the public participation venue of U.

The elemental abundance pattern in a galaxy at z = 2.626.

The discovery of metal-poor stars (where metal is any element more massive than helium) has enabled astronomers to probe the chemical enrichment history of the Milky Way. More recently, element abundances in gas inside high-redshift galaxies has been probed through the absorption lines imprinted on the spectra of background quasars, but these have typically yielded measurements of only a few elements. Furthermore, interpretation of these abundances is complicated by the fact that differential incorporation of metals into dust can produce an abundance pattern similar to that expected from nucleosynthesis by massive stars.

Human toxocariasis and direct contact with dogs.

Toxocariasis in man is traditionally thought to be contracted through the ingestion of eggs from contaminated soil. The disease may manifest itself in different syndromes such as ocular larval migrans, visceral larval migrans and covert toxocariasis. This paper assesses the evidence for the soil contamination hypothesis and proposes that direct contact with dogs may provide a better explanation of the epidemiology of the disease.

Experience with reduction mammaplasty combined with breast conservation therapy in the treatment of breast cancer.

As the inclusion criteria for breast conservation therapy have continued to evolve to include lower quadrant tumors, very large breasts, and central tumors, the potential for significant disfigurement after breast conservation therapy has also increased. This has led some centers to develop coordinated oncology-plastic surgery approaches to ensure both adequate cancer resection and aesthetic appearance to the breasts. The authors applied this principle to a specific group of breast cancer patients--women with macromastia--who would benefit from reduction mammaplasty.

Design and synthesis of 8-hydroxy-[1,6]naphthyridines as novel inhibitors of HIV-1 integrase in vitro and in infected cells.

Naphthyridine 7 inhibits the strand transfer of the integration process catalyzed by integrase with an IC50 of 10 nM and inhibits 95% of the spread of HIV-1 infection in cell culture at 0.39 microM. It does not exhibit cytotoxicity in cell culture at < or =12.

Inhibition of HIV-1 ribonuclease H by a novel diketo acid, 4-[5-(benzoylamino)thien-2-yl]-2,4-dioxobutanoic acid.

Human immunodeficiency virus-type 1 (HIV-1) reverse transcriptase (RT) coordinates DNA polymerization and ribonuclease H (RNase H) activities using two discrete active sites embedded within a single heterodimeric polyprotein. We have identified a novel thiophene diketo acid, 4-[5-(benzoylamino)thien-2-yl]-2,4-dioxobutanoic acid, that selectively inhibits polymerase-independent RNase H cleavage (IC(50) = 3.2 microm) but has no effect on DNA polymerization (IC(50) > 50 microm).

Germs in space. Joshua Lederberg, exobiology, and the public imagination, 1958-1964.

Under the leadership of Joshua Lederberg, some American biologists and chemists proposed exobiology as the most legitimate program for space research. These scientists used the fear of contamination--of earth and other planets--as a central argument for funding "nonpolitical," "scientifically valid" experiments in extraterrestrial life detection. Exobiology's resemblance to popular science fiction narratives presented a significant challenge to its advocates' scientific authority.

Spectrofluorescence of sediment humic substances and historical changes of lacustrine organic matter provenance in response to atmospheric nutrient enrichment.

Humic substances were extracted from the sediments of two small alpine lakes in the Colorado Front Range and characterized by three-dimensional fluorescence spectroscopy. The fluorescence index (FI), defined as the ratio of fluorescence emitted at 450 nm to that emitted at 500 nm from an excitation wavelength of 370 nm, was computed and thereafter compared to additional sediment proxies of recent environmental change. Stratigraphic changes in both sediment C:N ratios and diatom assemblages parallel those of Fl, together indicating pronounced increases in the contribution of autochthonous organic matter to lake sediments since the mid-20th century.

The coincidence of TRAM flaps and prostheses in the setting of breast reconstruction.

It is well known that transverse rectus abdominis myocutaneous (TRAM) flaps can be used to replace unsatisfactory prosthetic breast reconstructions; however, little has been written about the scope of breast implant use in TRAM flap patients. In this study, to ascertain the range of such therapeutic options, their frequency, and their clinical outcomes, the authors retrospectively reviewed the senior author's breast reconstruction experience from 1989 to 2000 with patients in whom both a TRAM flap and an implant were used for breast reconstruction. The authors examined the surgical indications, body habitus, bra size, chest wall irradiation history, flap type, implant type, complications, and outcomes for those patients with TRAM flap and breast implant combinations.

Characterizing gene expression during lens formation in Xenopus laevis: evaluating the model for embryonic lens induction.

Few directed searches have been undertaken to identify the genes involved in vertebrate lens formation. In the frog Xenopus, the larval cornea can undergo a process of transdifferentiation to form a new lens once the original lens is removed. Based on preliminary evidence, we have shown that this process shares many elements of a common molecular/genetic pathway to that involved in embryonic lens development.

Reactive nitrogen and human health: acute and long-term implications.

Reactive-nitrogen (Nr) has a wide variety of beneficial and detrimental effects on human health. The most important of the beneficial effects are increasing global and regional food supplies and increased nutritional quality of available foods. However, lack of adequate dietary intake of amino acids and proteins is a serious cause of malnutrition when food supplies are inadequate because of poverty, drought, floods, wars, and displacements of people as refugees.

Diketo acid inhibitor mechanism and HIV-1 integrase: implications for metal binding in the active site of phosphotransferase enzymes.

The process of integrating the reverse-transcribed HIV-1 DNA into the host chromosomal DNA is catalyzed by the virally encoded enzyme integrase (IN). Integration requires two metal-dependent reactions, 3' end processing and strand transfer. Compounds that contain a diketo acid moiety have been shown to selectively inhibit the strand transfer reaction of IN in vitro and in infected cells and are effective as inhibitors of HIV-1 replication.

Independent regulation of the divergent Escherichia coli nrfA and acsP1 promoters by a nucleoprotein assembly at a shared regulatory region.

Expression from the Escherichia coli nrfA promoter (pnrfA) is activated by both the FNR protein (an anaerobically triggered transcription activator) and the NarL or NarP proteins (transcription activators triggered by nitrite and nitrate). Under anaerobic conditions, FNR binds to a site centred at position -41.5 at pnrfA and activates transcription.

Identification of a discrete promoter region of the human GnRH gene that is sufficient for directing neuron-specific expression: a role for POU homeodomain transcription factors.

The human GnRH (hGnRH) gene is expressed, and the GnRH decapeptide produced, primarily in the GnRH neurons of the diencephalon. The molecular elements important for the cell-specific expression and regulation of the hGnRH gene are not well established at this time; therefore, we have used a transgenic mouse model to isolate cis-regulatory elements important for directing gene expression to GnRH neurons in the hypothalamus. Gene constructs consisting of various promoter deletion fragments of the hGnRH gene fused to the luciferase (LUC) reporter gene have been used to create transgenic mouse lines.

Pyridophens: binary pyridostigmine-aprophen prodrugs with differential inhibition of acetylcholinesterase, butyrylcholinesterase, and muscarinic receptors.

A series of "binary prodrugs" called carbaphens,(1) carbamylated derivatives on one or both of the aromatic rings of the muscarinic receptor antagonist aprophen [(N,N-diethylamino)ethyl 2,2-diphenylpropionate], were synthesized to develop binary prophylactic agents against organophosphorus intoxication. As a group, the carbaphens retained the muscarinic receptor antagonist properties of aprophen but also preferentially inhibited butyrylcholinesterase (BChE) in contrast to acetylcholinesterase (AChE). Therefore, a new series of compounds named pyridophens were designed and synthesized to achieve binary prodrugs to preferentially inhibit AChE over BChE, while still retaining the muscarinic receptor antagonism of aprophen.

Red foxes (Vulpes vulpes) in Ireland as hosts for parasites of potential zoonotic and veterinary significance.

Intestinal washes, faecal flotations and serological examinations for antibodies to Toxoplasma gondii and Neospora caninum were used to assess the prevalence of parasites in carcases of foxes killed on roads or shot in the Dublin area and surrounding counties. The ascarids Uncinaria stenocephala and Toxocara canis were prevalent, as was the trematode Alaria alata. Taenia species, eggs of Capillaria species and sporocysts of Sarcocystis species were also found.