Development of an in Vitro Assay for the Proteolytic Processing of the CDP/Cux Transcription Factor

Hebert, Sherry,Berube, Ginette,Nepveu, Alain Korean Society for Biochemistry and Molecular Biol 2003 Journal of biochemistry and molecular biology Vol.36 No.4

The CDP/Cux transcription factor was previously shown to be proteolytically processed at the G1/S transition. In view of characterizing and eventually identifying the protease responsible for CDP/Cux processing, we have established an in vitro proteolytic processing assay. CDP/Cux recombinant proteins expressed in mammalian or bacterial cells were efficiently processed in vitro using as a source of protease either whole cell extracts, the nuclear or the cytoplasmic fraction. Processing was found to take place optimally at a lower pH, to be insensitive to variations in salt concentration, and to be inhibited by the protease inhibitors MG132 and E64D. Interestingly, the bacterially-produced substrate was more efficiently processed than the substrate purified from mammalian cells. Moreover, processing in vitro was more efficient when CDP/Cux substrates were purified from populations of cells enriched in the S phase than in the G1 phase of the cell cycle. Altogether, these results suggest that post-translational modifications of CDP/Cux in mammalian cells inhibits processing and contributes to the cell cycle-dependent regulation of processing. The in vitro processing assay described in this study will provide a useful tool for the purification and identification of the protease responsible for the processing of CDP/Cux.

Adhesion as a tool for in-built nanotechnology design in cementitious materials

Hebert L. Rossetto,Milton F. de Souza,Victor C. Pandolfelli 한양대학교 세라믹연구소 2010 Journal of Ceramic Processing Research Vol.11 No.3

Confined water, such as those molecules in nanolayers of 2-3 nm in length, plays an important role in the adhesion of hydrophilic materials, mainly in cementitious ones. In this study, the effects of water containing kosmotropic substances on adhesion, known for their ability of enhancing the hydrogen bond (H-bond) network of confined water, were evaluated using mechanical strength tests. Indeed, to link adhesion provided by water confined in nanolayers to a macro-response of the cementitious samples, such as the bending strength, requires the evaluation of local water H-bond network configuration in the presence of kosmotropes, considering their influences on the extent and the strength of H-bonds. Among the kosmotropes,trimethylamine and sucrose provided a 50% increase in bending strength compared to the reference samples, the latter just using water as an adhesive, whereas trehalose was responsible for reducing the bending strength to a value close to the samples without any adhesive. The results attained opened up perspectives regarding exploring the confined water behavior which naturally occurs throughout the hydration process in cement-based materials.

Development of an in Vitro Assay for the Proteolytic Processing of the CDP/Cux Transcription Factor

( Sherry Hebert ),( Ginette Berube ),( Alain Nepveu ) 생화학분자생물학회 2003 BMB Reports Vol.36 No.4

the CDP/Cux transcription factor was previously shown to be proteolytically processed at the G1/S transition. In view of characterizing and eventually identifying the protease responsible for CDP/Cux processing, we have established an in vitro proteolytic processing assay. CDP/Cux recombinant proteins expressed in mammalian or bacterial cells were efficiently processed in vitro using as a source of protease either whole cell extracts, the nuclear or the cytoplasmic fraction. Processing was found to take place optimally at a lower pH, to be insensitive to variations in salt concentration, and to be inhibited by the protease inhibitors MG132 and E64D. Interestingly, the bacterially-produced substrate was more efficiently processed than the substrate purified from mammalian cells. Moreover, processing in vitro was more efficient when CDP/Cux substrates were purified from populations of cells enriched in the S phase than in the G1 phase of the cell cycle. Altogether, these results suggest that post-translational modifications of CDP/Cux in mammalian cells inhibits processing and contributes to the cell cycle-dependent regulation of processing. The in vitro processing assay described in this study will provide a useful tool for the purification and identification of the protease responsible for the processing of CDP/Cux.

Role of the Calcium Sensing Receptor (CaSR) in Divalent Mineral Ion Homeostasis

( Steven C. Hebert ) 대한신장학회 2003 춘계학술대회 초록집 Vol.22 No.1

Penile Prosthesis Infection: Myths and Realities

Kevin J. Hebert,Tobias S. Kohler 대한남성과학회 2019 The World Journal of Men's Health Vol.37 No.3

Penile prosthesis infection is the most significant complication following prosthesis implant surgery leading to postoperative morbidity, increased health care costs, and psychological stress for the patient. We aimed to identify risk factors associated with increased postoperative penile prosthesis infection. A review of the literature was performed via PubMed using search terms including inflatable penile prosthesis, penile implant, and infection. Articles were given a level of evidence score using the 2011 Oxford Centre for Evidence-Based Medicine Guidelines. Multiple factors were associated with increased risk of post-prosthesis placement infection (Level of Evidence Rating) including smoking tobacco (Level 1), CD4 T-cell count <300 (Level 4), Staphylococcus aureus nasal carriage (Level 2), revision surgery (Level 2), prior spinal cord injury (Level 3), and hemoglobin A1c level >8.5 (Level 2). Factors with no effect on infection rate include: preoperative cleansing with antiseptic (Level 4), history of prior radiation (Level 3), history of urinary diversion (Level 4), obesity (Level 3), concomitant circumcision (Level 3), immunosuppression (Level 4), age >75 (Level 4), type of hand cleansing (Level 1), post-surgical drain placement (Level 3), and surgical approach (Level 4). Factors associated with decreased rates of infection included: surgeon experience (Level 2), “No Touch” technique (Level 3), preoperative parenteral antibiotics (Level 2), antibiotic coated devices (Level 2), and operative field hair removal with clippers (Level 1). Optimization of pre-surgical and intraoperative risk factors is imperative to reduce the rate of postoperative penile prosthesis infection. Additional research is needed to elucidate risk factors and maximize benefit.

Renal Potassium (K) Channels: Lessons from Molecular Cloning and Genetics

( Steven C. Hebert ) 대한신장학회 2003 춘계학술대회 초록집 Vol.22 No.1

학술발표회 초록 ( 재료 (Ⅰ) )

탁용석(Yong Sug Tak),Kurt R . Hebert(Kurt R . Hebert) 한국화학공학회 1994 춘계학술발표회 Vol.- No.-

Survey of DNA barcoding of Hemiptera

Doo-Sang Park,Paul D.H. Hebert 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.10

Recently, hundreds thousands of CO1 barcodes have been produced in many insect groups however, relatively little is known in Hemiptera. In this study, we newly determine 1173 sequences for 374 species distributed among 190 genera and 33 families collected mostly from North America. Average age of the specimen was 12.2 years and about 70% of the specimens produce barcode over 500 bp among examined 1700 specimens. Con-generic divergency calculated by K2P distance was 9.99 which was 11fold higher than the mean intraspecific variation. A steady increase of genetic variation through increasing taxonomic levels was also observed. We found several taxon groups with deep divergency (over 2.0 K2P distance) which were morphologically identified as a same species. Some mixed clusters with several species were also found and suggested more detailed study for these clusters through both morphological and molecular biological method.

DNA barcodes for two scale insect families, mealybugs (Hemiptera: Pseudococcidae) and armored scales (Hemiptera: Diaspididae)

Doo-Sang Park,Soo-Jung Suh,Paul D.N. Hebert,Ki-Jeong Hong,Hyun-Woo Oh 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.10

Although DNA barcode coverage has grown rapidly for many insect orders, there are some groups, such as scale insects, where sequence recovery has been difficult. However, using a recently developed primer set, we recovered barcode records from 373 specimens, providing coverage for 75 species from 31 genera in two families. Overall success was >90% for mealybugs and >80% for armored scale species. The G·C content was very low in most species, averaging just 16.3%. Sequence divergences (K2P) between congeneric species averaged 10.7%, while intraspecific divergences averaged 0.97%. However, the latter value was inflated by high intra-specific divergence in nine taxa, cases that may indicate species overlooked by current taxonomic treatments. Our study establishes the feasibility of developing a comprehensive barcode library for scale insects and indicates that its construction will both create an effective system for identifying scale insects and reveal taxonomic situations worthy of deeper analysis.

Plasma Kinetic Study of Silicon-Dioxide Removal with Fluorocompounds in a Plasma-Enhanced Chemical Vapor Deposition Chamber

채희엽,Hebert H. Sawin 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.3

Plasma kinetics of silicon dioxide plasma cleaning is investigated with C2F6 and CF3CF2OCF=CF2 (perfluoroethyl vinyl ether, PEVE) in this work. Perfluorocompounds (PFCs) are widely used in the semiconductor industry, and they are known to have long atmospheric lifetimes and high global warming potentials (GWP) due to their chemical stability and large cross sections for infrared radiation absorption. The silicon dioxide (SiO2) cleaning process in a plasmaenhanced chemical vapor deposition (PECVD) chamber is known to be the largest PFC emission source for the semiconductor industry. Silicon-dioxide removal rates by surface reactions in plasmas were measured in the temperature range from room temperature to 400 C by using laser interferometry, and the fluorine density was determined by using an optical emission spectroscopy (OES) actinometry technique. The ion density and the ion energy were determined by using an impedance analysis and an equivalent circuit model. The activation energy was determined from Arrehenius plot to be 0.163 eV and 0.169 eV for C2F6 and PEVE plasmas, respectively, in the PECVD chamber cleaning condition. It is shown here that silicon-dioxide removal rate is linearly proportional to the fluorine concentration for the PECVD chamber cleaning condition of 300 . 400 C and that the removal rate depends on the ion flux and the ion energy below 100 C. The combined etch rate model is suggested to explain this temperature dependence in this work. From this plasma kinetic study, we can conclude that the atomic fluorine concentration is the dominant factor in silicon-dioxide removal for the PECVD chamber cleaning condition.