14th Annual Conference on Legal Issues For Financial Institutions

Materials from the 14th Annual Conference on Legal Issues For Financial Institutions held by UK/CLE in March 1994

Ethylene-Binding Activity, Gene-Expression Levels, and Receptor-System Output for Ethylene-Receptor Family Members from Arabidopsis and Tomato

Ethylene signaling in plants is mediated by a family of ethylene receptors related to bacterial two-component regulators. Expression in yeast of ethylene-binding domains from the five receptor isoforms from Arabidopsis thaliana and five-receptor isoforms from tomato confirmed that all members of the family are capable of high-affinity ethylene-binding activity. All receptor isoforms displayed a similar level of ethylene binding on a per unit protein basis, while members of both subfamily I and subfamily II from Arabidopsis showed similar slow-release kinetics for ethylene. Quantification of receptor-isoform mRNA levels in receptor-deficient Arabidopsis lines indicated a direct correlation between total message level and total ethylene-binding activity in planta. Increased expression of remaining receptor isoforms in receptor-deficient lines tended to compensate for missing receptors at the level of mRNA expression and ethylene-binding activity, but not at the level of receptor signaling, consistent with specialized roles for family members in receptor signal output

Fabrication of an ammonia gas sensor using inkjet-printed polyaniline nanoparticles

This work details the fabrication and performance of a sensor for ammonia gas analysis which has been constructed via the inkjet-printed deposition of polyaniline nanoparticle films. The conducting films were assembled on interdigitated electrode arrays and characterised with respect to their layer thickness and thermal properties. The sensor was further combined with heater foils for operation at a range of temperatures. When operated in a conductimetric mode, the sensor was shown to exhibit temperature-dependent analytical performance to ammonia detection. At room temperature, the sensor responded rapidly to ammonia (t50 = 15 s). Sensor recovery time, response linearity and sensitivity were all significantly improved by operating the sensor at temperatures up to 80 °C. The sensor was found to have a stable logarithmic response to ammonia in the range of interest (1–100 ppm). The sensor was also insensitive to moisture in the range from 35 to 98% relative humidity. The response of the sensor to a range of common potential interferents was also studied

Inhibition of a secreted glutamic peptidase prevents growth of the fungustalaromyces emersonii

secretes a variety of hydrolytic enzymes that are of interest for processing of biomass into fuel. Many carbohydrases have been isolated and characterized from this fungus, but no studies had been performed on peptidases. In this study, two acid-acting endopeptidases were isolated and characterized from the culture filtrate of T. emersonii. One of these enzymes was identified as a member of the recently classified glutamic peptidase family and was subsequently named T. emersonii glutamic peptidase 1 (TGP1). The second enzyme was identified as an aspartyl peptidase (PEP1). TGP1 was cloned and sequenced and shown to exhibit 64 and 47% protein identity to peptidases from Aspergillus niger and Scytalidium ligno-colum, respectively. Substrate profiling of 16 peptides determined that TGP1 has broad specificity with a preference for large residues in the P1 site, particularly Met, Gln, Phe, Lys, Glu, and small amino acids at P1\u27 such as Ala, Gly, Ser, or Thr. This enzyme efficiently cleaves an internally quenched fluorescent substrate containing the zymogen activation sequence (k(cat)/K-m = 2 x 10(5) M-1 s(-1)). Maximum hydrolysis occurs at pH 3.4 and 50 degrees C. The reaction is strongly inhibited by a transition state peptide analog, TA1 (K-i = 1.5 nM), as well as a portion of the propeptide sequence, PT1 (K-i = 32 nM). Ex vivo studies show that hyphal extension of T. emersonii in complex media is unaffected by the aspartyl peptidase inhibitor pepstatin but is inhibited by TA1 and PT1. This study provides insight into the functional role of the glutamic peptidase TGP1 for growth of T. emersonii