The alternatively spliced acid box region plays a key role in FGF receptor autoinhibition

Uncontrolled fibroblast growth factor (FGF) signaling can lead to human malignancies necessitating multiple layers of self-regulatory control mechanisms. Fibroblast growth factor receptor (FGFR) autoinhibition mediated by the alternatively spliced immunoglobulin (Ig) domain 1 (D1) and the acid box (AB)-containing linker between D1 and Ig domain 2 (D2) serves as the first line of defense to minimize inadvertent FGF signaling. In this report, nuclear magnetic resonance and surface plasmon resonance spectroscopy are used to demonstrate that the AB subregion of FGFR electrostatically engages the heparan sulfate (HS)-binding site on the D2 domain in cis to directly suppress HS-binding affinity of FGFR. Furthermore, the cis electrostatic interaction sterically autoinhibits ligand-binding affinity of FGFR because of the close proximity of HS-binding and primary ligand-binding sites on the D2 domain. These data, together with the strong amino acid sequence conservation of the AB subregion among FGFR orthologs, highlight the universal role of the AB subregion in FGFR autoinhibition.     

Ranitidine induces inhibition and structural changes in sucrase

Ranitidine is an antagonist of histamine-2 (H(2)) receptor. It is employed to treat peptic ulcer and other conditions in which gastric acidity must be reduced. Sucrase is a hydrolytic enzyme that catalyzes the breakdown of sucrose to its monomer content. A liquid of yeast sucrase was developed for treatment of congenital sucrase-isomaltase deficiency (CSID) in human. In this study, the effect of ranitidine on yeast sucrase activity was investigated. Our results showed that ranitidine binds to sucrase and inhibits the enzyme in a noncompetitive manner. The K(i) and IC(50) values were measured to be about 2.3 and 2.2 mM, respectively. Fluorescence measurement showed conformational changes after binding of ranitidine to the enzyme. The fluorescence spectra showed that ranitidine could bind to both free enzyme and enzyme-substrate complex, which was accompanied with reduction of emission intensity and red shift production.     

Optimization of biological sulfide removal in a CSTR bioreactor

In this study, biological sulfide removal from natural gas in a continuous bioreactor is investigated for estimation of the optimal operational parameters. According to the carried out reactions, sulfide can be converted to elemental sulfur, sulfate, thiosulfate, and polysulfide, of which elemental sulfur is the desired product. A mathematical model is developed and was used for investigation of the effect of various parameters on elemental sulfur selectivity. The results of the simulation show that elemental sulfur selectivity is a function of dissolved oxygen, sulfide load, pH, and concentration of bacteria. Optimal parameter values are calculated for maximum elemental sulfur selectivity by using genetic algorithm as an adaptive heuristic search. In the optimal conditions, 87.76% of sulfide loaded to the bioreactor is converted to elemental sulfur.     

Expression of Integrin ��v��6 and TGF-�� in Scarless vs Scar-forming Wound Healing

Oral mucosal wounds heal with reduced scar formation compared with skin. The epithelial integrin αvβ6 is induced during wound healing, and it can activate fibrogenic transforming growth factor β1 (TGF-β1) and anti-fibrogenic TGF-β3 that play key roles in scar formation. In this study, expression of β6 integrin and members of the TGF-β pathway were studied in experimental wounds of human gingiva and both gingiva and skin of red Duroc pigs using real-time PCR, gene microarrays, and immunostaining. Similar to human wounds, the expression of β6 integrin was induced in the pig wounds 7 days after wounding and remained upregulated >49 days. The αvβ6 integrin was colocalized with both TGF-β isoforms in the wound epithelium. Significantly higher expression levels of β6 integrin and TGF-β1 were observed in the pig gingival wounds compared with skin. Early gingival wounds also expressed higher levels of TGF-β3 compared with skin. The spatio-temporal colocalization of αvβ6 integrin with TGF-β1 and TGF-β3 in the wound epithelium suggests that αvβ6 integrin may activate both isoforms during wound healing. Prolonged expression of αvβ6 integrin along with TGF-β3 in the gingival wound epithelium may be important in protection of gingiva from scar formation. (J Histochem Cytochem 57:543–557, 2009)     

Outer membrane vesicle of<Emphasis Type="Italic">Neisseria meningitidis</Emphasis> serogroup B as an adjuvant to induce specific antibody response against the lipopolysaccharide of<Emphasis Type="Italic">Brucella abortus</Emphasis> S99

Brucellosis is a worldwide zoonosis and represents one of the most important public health problems in many countries, especially around the Mediterranean basin, Middle East, India and Central and South America. Currently subunit vaccines are being considered to develop effective vaccines for human which has been evidenced by vaccines currently available against the infections such as meningococcal diseases and influenza. The application of new adjuvants of microbial origins is also underway to design subunit vaccines promoting the immune responses to the antigenic determinant(s) of the vaccine. In order to explore the efficacy ofBrucella abortus lipopolysaccharide (LPS) combined with different adjuvants and proteins (as a vaccine candidate) in the induction of immune response as an effective and long-lasting immunity againstBrucella, we evaluated the outer membrane vesicle ofNeisseria meningitidis serogroup B (GBMOMV) as a subcutaneous adjuvant and a part of a brucellosis candidate vaccine to induce high titres of specific anti-Brucella abortus S99 LPS in animal model (mice). The obtained results were compared with complete and incomplete Freund’s adjuvants (CFA and IFA). LPS+GBMOMV was the most immunogenic compound that stimulated following the first injection and increase in IgG titre of about 3.90, 3.18 and 1.58 fold higher than that produced against LPS, LPS+IFA and LPS+CFA, respectively. The highest anti-LPS IgG titre was detected two weeks after the third injection (the day 42) of LPS+GBMOMV. Purified GBMOMV can be considered as a safe subcutaneous adjuvant and a part of a candidate vaccine when combined with lipopolysaccharide ofBrucella abortus S99.     

Optimization of Non-Nutritional Factors for a Cost-Effective Enhancement of Nisin Production Using Orthogonal Array Method

In order to increase nisin production in a cost-effective manner, non-nutritional factors as well as nutritional parameters must be optimized. In this study, optimization of the most important non-nutritional factors for nisin production using orthogonal array method was performed. Optimization of temperature, agitation, age and size of inoculum, medium initial pH value and flask volume/medium volume ratio in de Man, Rogosa and Sharpe (MRS) medium in batch fermentation was accomplished. Nisin was produced by Lactococcus lactis subsp. lactis PTCC 1336 and measured by bioassay method using Micrococcus luteus PTCC 1169 as the nisin-sensitive strain. The optimum levels of non-nutritional factors for maximum nisin production and productivity were obtained as: flask volume/medium volume ratio: 5.00, medium initial pH value: 8.00, inoculum size: 1%, inoculum age: 24 h old (A = 1.7), agitation: 100 rpm and temperature: 27 °C. Under the optimized conditions, maximum nisin production and maximum nisin productivity were 599.70 IU/mL and 37.48 IU/mL/h, respectively.     

THE USE OF BEEF LIVER CATALASE AS A PROTEIN TRACER FOR ELECTRON MICROSCOPY

Beef liver catalase was injected intravenously into mice, and its distribution in the kidney, myocardium, and liver was studied with the electron microscope. A specific and relatively sensitive method was developed for its ultrastructural localization, based on the peroxidatic activity of catalase and employing a modified Graham and Karnovsky incubation medium. The main features of the medium were a higher concentration of diaminobenzidine, barium peroxide as the source of peroxide, and pH of 8.5. Ultrastructurally, the enzyme was seen to permeate the endothelial fenestrae and basement membranes of tubular and glomerular capillaries of the kidney. The urinary space and tubular lumina contained no reaction product. In the myocardial capillaries, the tracer filled the pinocytotic vesicles but did not diffuse across the intercellular clefts of the endothelium. In liver, uptake of catalase was seen both in hepatocytes and in Kupffer cells.     

Peroxisomes (microbodies) in the myocardium of rodents and primates

Summary The occurrence of peroxisomes (microbodies), their cytochemical characteristics and their ultrastructural relationship to the neighboring organelles were investigated in the ventricular myocardium of four rodent (rat, rabbit, gerbil, and guinea pig) and two primate (Macaca Java and Tupaya) species. The hearts were fixed by vascular perfusion with glutaraldehyde and incubated in alkaline diaminobenzidine media for visualization of catalase. The electron-dense reaction product of catalase was found in the myocardium of all examined species and was localized in 0.2–0.5 m oval particles, surrounded by a single limiting membrane and located usually at the junction of I and A bands. The peroxisomes in the hearts of gerbil and Macaca java were especially long and tortuous. A close spatial association was found between the myocardial peroxisomes and mitochondria, lipid droplets, and the membranes of sarcoplasmic reticulum, especially the so-called junctional sarcoplasmic reticulum. These observations demonstrate the consistent occurrence of peroxisomes in the heart of various mammalian species and suggest that peroxisomes have important metabolic and physiological functions in myocardium.This study was supported by Grant 08533 from the National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland and a grant from Sonderforschungs-bereich 90 (Cavas) of the Deutsche Forschungsgemeinschaft, Germany. Dr. Fahimi was the recipient of a Research Career Development Award from the National Institutes of Health, Bethesda, Maryland. The technical assistance of Ms. Gaby Krämer and Mr. Michel Le Hir as well as the secretarial help of Ms. Gina Folsom is gratefully acknowledged