Effect of Tryptophan Analogs on Derepression of the \u3cem\u3eEscherichia coli\u3c/em\u3e Tryptophan Operon by Indole-3-Propionic Acid

The abilities of 14 tryptophan analogs to repress the tryptophan (trp) operon have been studied in Escherichia coli cells derepressed by incubation with 0.25 mM indole-3-propionic acid (IPA). trp operon expression was monitored by measuring the specific activities of anthranilate synthase (EC 4.1.3.27) and the tryptophan synthase (EC 4.2.1.20) β subunit. Analogs characterized by modification or removal of the α-amino group or the α-carboxyl group did not repress the trp operon. The only analogs among this group that appeared to interact with the trp aporepressor were IPA, which derepressed the trp operon, and d-tryptophan. Analogs with modifications of the indole ring repressed the trp operon to various degrees. 7-Methyl-tryptophan inhibited anthranilate synthase activity and consequently derepressed the trp operon. Additionally, 7-methyltryptophan prevented IPA-mediated derepression but, unlike tryptophan, did so in a non-coordinate manner, with the later enzymes of the operon being relatively more repressed than the early enzymes. The effect of 7-methyltryptophan on IPA-mediated derepression was likely not due to the interaction of IPA with the allosteric site of anthranilate synthase, even though feedback-resistant mutants of anthranilate synthase were partially resistant to derepression by IPA. The effect of 7-methyltryptophan on derepression by IPA was probably due to the effect of the analog-aporepressor complex on trp operon expression

Notes on the Distribution and Natural History of the Eastern Wormsnake (Carphophis amoenus amoenus) in West Virginia

Small fossorial snakes, such as the Eastern Wormsnake (Carphophis amoenus amoenus), are often neglected in studies since they lead a fossorial life and are frequently hard to find. Since it was last studied nearly 40 years ago, we present an update on distribution, habitat preferences, and diet of the Eastern Wormsnake in West Virginia. We found that this species resides in only a fraction of its original range due to habitat destruction by industrial, residential, and commercial developments. Habitat data suggests this species can tolerate a range of soil temperatures (15–24 °C), air temperatures (23.1 degrees Celsius), and relative humidity (24.5-80%), and can be found on nearly all slope directions. Dietary analysis showed annelids make up the majority of their diet but other invertebrate prey are also taken

Experimental study of the effects of Reynolds number on high angle of attack aerodynamic characteristics of forebodies during rotary motion

The National Aeronautics and Space Administration and the Defense Research Agency (United Kingdom) have ongoing experimental research programs in rotary-flow aerodynamics. A cooperative effort between the two agencies is currently underway to collect an extensive database for the development of high angle of attack computational methods to predict the effects of Reynolds number on the forebody flowfield at dynamic conditions, as well as to study the use of low Reynolds number data for the evaluation of high Reynolds number characteristics. Rotary balance experiments, including force and moment and surface pressure measurements, were conducted on circular and rectangular aftbodies with hemispherical and ogive noses at the Bedford and Farnborough wind tunnel facilities in the United Kingdom. The bodies were tested at 60 and 90 deg angle of attack for a wide range of Reynolds numbers in order to observe the effects of laminar, transitional, and turbulent flow separation on the forebody characteristics when rolling about the velocity vector

Detection of the argonaute protein Ago2 and microRNAs in the RNA induced silencing complex (RISC) using a monoclonal antibody

MicroRNAs (miRNAs) are short RNA molecules responsible for post-transcriptional gene silencing by the degradation or translational inhibition of their target messenger RNAs (mRNAs). This process of gene silencing, known as RNA interference (RNAi), is mediated by highly conserved Argonaute (Ago) proteins which are the key components of the RNA induced silencing complex (RISC). In humans, Ago2 is responsible for the endonuclease cleavage of targeted mRNA and it interacts with the mRNAbinding protein GW182, which is a marker for cytoplasmic foci referred to as GW bodies (GWBs). We demonstrated that the antiAgo2 monoclonal antibody 4F9 recognized GWBs in a cell cycle dependent manner and was capable of capturing miRNAs associated with Ago2. Since Ago2 protein is the effector protein of RNAi, anti-Ago2 monoclonal antibody may be useful in capturing functional miRNAs

Upregulated miR-146a expression in peripheral blood mononuclear cells from rheumatoid arthritis patients

Introduction MicroRNAs are small noncoding RNA molecules that negatively regulate gene expression via degradation or translational repression of their targeted mRNAs. It is known that aberrant microRNA expression can play important roles in cancer, but the role of microRNAs in autoimmune diseases is only beginning to emerge. In this study, the expression of selected microRNAs is examined in rheumatoid arthritis. Methods Total RNA was isolated from peripheral blood mononuclear cells obtained from patients with rheumatoid arthritis, and healthy and disease control individuals, and the expression of miR-146a, miR-155, miR-132, miR-16, and microRNA let-7a was analyzed using quantitative real-time PCR. Results Rheumatoid arthritis peripheral blood mononuclear cells exhibited between 1.8-fold and 2.6-fold increases in miR-146a, miR-155, miR-132, and miR-16 expression, whereas let-7a expression was not significantly different compared with healthy control individuals. In addition, two targets of miR-146a, namely tumor necrosis factor receptor-associated factor 6 (TRAF6) and IL-1 receptor-associated kinase 1 (IRAK-1), were similarly expressed between rheumatoid arthritis patients and control individuals, despite increased expression of miR-146a in patients with rheumatoid arthritis. Repression of TRAF6 and/or IRAK-1 in THP-1 cells resulted in up to an 86% reduction in tumor necrosis factor-α production, implicating that normal miR-146a function is critical for the regulation of tumor necrosis factor-α production. Conclusions Recent studies have shown that synovial tissue and synovial fibroblasts from patients with rheumatoid arthritis exhibit increased expression of certain microRNAs. Our data thus demonstrate that microRNA expression in rheumatoid arthritis peripheral blood mononuclear cells mimics that of synovial tissue/fibroblasts. The increased microRNA expression in rheumatoid arthritis patients is potentially useful as a marker for disease diagnosis, progression, or treatment efficacy, but this will require confirmation using a large and well defined cohort. Our data also suggest a possible mechanism contributing to rheumatoid arthritis pathogenesis, whereby miR-146a expression is increased but unable to properly function, leading to prolonged tumor necrosis factor-α production in patients with rheumatoid arthritis

An Observational Study of the "Interstate 5" Dust Storm Case

On 29 November 1991 a series of collisions involving 164 vehicles occurred on Interstate 5 in the San Joaquin Valley in California in a dust storm that reduced visibility to near zero. The accompanying high surface winds are hypothesized to result from intense upper-trophospheric downward motion that led to the formation of a strong upper front and tropopause fold and that transported high momentum air downward to midlevels where boundary layer processed could then mix it to the surface. The objectives of the research presented in this paper are to document the event, to provide support for the hypothesis that both upper-level and boundary layer processes were important, and to determine the structure of the mesoscale circulations in this case for future use in evaluating the navy's mesoscale data assimilation system..