The influence of bovine serum albumin on β-lactoglobulin denaturation, aggregation and gelation

peer-reviewedThe effect of bovine serum albumin (BSA) on the heat-induced denaturation, aggregation and subsequent acid-induced gelation of β-lactoglobulin (β-lg) was investigated in this work. Changes in the denaturation kinetics of β-lg during heating at 78 °C were determined by monitoring the disappearance of the native protein by reverse-phase chromatography. Replacing β-lg with increasing amounts of BSA, while keeping the total protein concentration constant at 5% (w/w), significantly increased the denaturation rate of β-lg from 2.57±0.30×10−3(g L−1)(1−n)s−1 to 5.07±0.72×10−3(g L−1)(1−n)s−1 (β-lg: BSA ratio of 3:1 w/w). The reaction order for β-lg was 1.40±0.09. Partial replacement of β-lg with BSA (β-lg: BSA ratio of 3:1 w/w) significantly increased the reaction order to 1.67±0.13. Heat-induced aggregates between β-lg and BSA were studied by dynamic light scattering, two-dimensional electrophoresis and size exclusion chromatography. The partial replacement of β-lg with BSA significantly changed the gelling properties of the acid-induced gels. A rapid rate of acidification resulted in a significant decrease, while a slow acidification rate resulted in a significant increase in gel strength. Size exclusion chromatography demonstrated that intermolecular disulphide bond formation occurred during both heat-induced denaturation/aggregation and subsequent acid-induced gelation. Results clearly indicate that BSA contributed to the formation of these disulphide bonds.This work was funded under the Food Institutional Research Measure (FIRM) of the National Development Plan 2000-2006. J. Kehoe is funded by the Teagasc Walsh Fellowship schem

Towards Interoperable Preservation Repositories (TIPR)

The TIPR Project, Towards Interoperable Preservation Repositories, was begun in October 2008, its participants being the Florida Center for Library Automation, the Bobst Library at New York University, and Cornell University Library. Our goal has been to develop, test, and promote a standard format for exchanging information packages among dissimilar preservation repositories - an intermediary information package that all repositories can read and write, overcoming the mismatch between repository types

Towards Interoperable Preservation Repositories (TIPR)

The TIPR Project, Towards Interoperable Preservation Repositories, was begun in October 2008, its participants being the Florida Center for Library Automation, the Bobst Library at New York University, and Cornell University Library. Our goal has been to develop, test, and promote a standard format for exchanging information packages among dissimilar preservation repositories - an intermediary information package that all repositories can read and write, overcoming the mismatch between repository types

Arsenic and Old Pelts: An Update on Deadly Pesticides in Museum Collections

The use of toxic chemicals within museums is an issue only recently addressed by anthropologists and scholars in related fields. A case of arsenic poisoning in an anthropologist during the 1960s is reviewed for what it may tell us about a mysterious ailment that afflicted Clark Wissler 50 years earlier. While no conclusive diagnosis can be made, Wissler’s case reminds us that we have come a long way in protecting against one of the lesser known dangers confronting anthropologists. All museums use pesticides and preservatives of some form, though the health impact of these agents is not always known. This necessary evil in the preservation of ethnographic collections can thus pose a health risk to people who work with or come in contact with treated objects. Here we open one cold case file, in which we believe a prominent American anthropologist may have directly suffered from the effects of poisons commonly used in the early nineteenth-century. Our own experience and recent inquiries provide one possible answer to the cause of the illness suffered by Clark Wissler

Passive Vibration Control of Airborne Equipment using a Circular Steel Ring

Vibration isolation is needed to protect avionics equipment from adverse aircraft vibration environments. Passive isolation is the simplest means to achieve this goal. The system used here consists of a circular steel ring with a lump mass on top and exposed to base excitation. Sinusoidal and filtered zero-mean Gaussian white noise are used to excite the structure and the acceleration response spectra at the top of the ring are computed. An experiment is performed to identify the natural frequencies and modal damping of the circular ring. Comparison is made between the analytical and experimental results and good agreement is observed. The ring response is also evaluated with a concentrated mass attached to the top of the ring. The effectiveness of the ring in isolating the equipment from base excitation is studied. The acceleration response spectra of a single degree of freedom system attached to the top of the ring are evaluated and the results are compared with those exposed directly to the base excitation. It is shown that a properly designed ring could effectively protect the avionics from possible damaging excitation levels

Chromatic Acclimation in Cyanobacteria: A Diverse and Widespread Process for Optimizing Photosynthesis

International audienc

Global Imbalances and Structural Change in the United States

Since the early 1990s, as the United States borrowed heavily from the rest of the world, employment in the US goods-producing sector has fallen.We construct a dynamic general equilibrium model with several mechanisms that could generate declining goods-sector employment: foreign borrowing, nonhomothetic preferences, and differential productivity growth across sectors. We find that only 15.1 percent of the decline in goods-sector employment from 1992 to 2012 stems from US trade deficits; most of the decline is due to differential productivity growth. As the United States repays its debt, its trade balance will reverse, but goods-sector employment will continue to fall

CpeT is the Phycoerythrobilin Lyase for Cys-165 on Beta-Phycoerythrin from Fremyella Diplosiphon and the Chaperone-like Protein CpeZ Greatly Improves its Activity.

Bilin lyases are enzymes which ligate linear tetrapyrrole chromophores to specific cysteine residues on light harvesting proteins present in cyanobacteria and red algae. The lyases responsible for chromophorylating the light harvesting protein phycoerythrin (PE) have not been fully characterized. In this study, we explore the role of CpeT, a putative bilin lyase, in the biosynthesis of PE in the cyanobacterium Fremyella diplosiphon. Recombinant protein studies show that CpeT alone can bind phycoerythrobilin (PEB), but CpeZ, a chaperone-like protein, is needed in order to correctly and efficiently attach PEB to the beta-subunit of PE. MS analyses of the recombinant beta-subunit of PE coexpressed with CpeT and CpeZ show that PEB is attached at Cys-165. Purified phycobilisomes from a cpeT knockout mutant and wild type (WT) samples from F. diplosiphon were analyzed and compared. The cpeT mutant contained much less PE and more phycocyanin than WT cells grown under green light, conditions which should maximize the production of PE. In addition, Northern blot analyses showed that the cpeCDESTR operon mRNAs were upregulated while the cpeBcpeA mRNAs were downregulated in the cpeT mutant strain when compared with WT, suggesting that CpeT may also play a direct or indirect regulatory role in transcription of these operons or their mRNA stability, in addition to its role as a PEB lyase for Cys-165 on beta-PE