The physicochemical property of shark type I collagen gel and membrane

The physicochemical properties of shark type I collagen gel and membrane were not same as those of pig type I collagen. The denaturation temperature of shark collagen gel was about 15 degrees C lower. According to scanning electronic micrography, the diameter of shark collagen fibril was relatively thin and more homogeneous. The breaking strength of shark collagen gel was greater, and shark collagen membrane had a greater mechanical strength and a higher water vapor sorption.     

Physical properties of shark gelatin compared with pig gelatin

Physical properties of shark gelatin were examined during gel formation and postgelation in comparison with pig gelatin. Samples with various concentrations and pH values were evaluated by breaking strength, dynamic viscoelasticity, and dynamic light scattering. Sol-gel and gel-sol transition temperatures for shark gelatin were remarkably lower than those for pig gelatin. Shark gelatin gel shows a narrower pH range to form a stable gel compared with pig gelatin. Melting enthalpy of shark gelatin gel was greater than that of pig gelatin gel, and G' of shark gelatin gel changed more extensively with rising temperature in comparison with pig gelatin gel. It is concluded that shark gelatin has different characteristics from pig gelatin not only for gel characteristics but also for the solution property.     

Cinnamon extract promotes type I collagen biosynthesis via activation of IGF-I signaling in human dermal fibroblasts

The breakdown of collagenous networks with aging results in hypoactive changes in the skin. Accordingly, reviving stagnant collagen synthesis can help protect dermal homeostasis against aging. We searched for type I collagen biosynthesis-inducing substances in various foods using human dermal fibroblasts and found that cinnamon extract facilitates collagen biosynthesis. Cinnamon extract potently up-regulated both mRNA and protein expression levels of type I collagen without cytotoxicity. We identified cinnamaldehyde as a major active component promoting the expression of collagen by HPLC and NMR analysis. Since insulin-like growth factor-I (IGF-I) is the most potent stimulator of collagen biosynthesis in fibroblasts, we examined the effect of cinnamaldehyde on IGF-I signaling. Treatment with cinnamaldehyde significantly increased the phosphorylation levels of the IGF-I receptor and its downstream signaling molecules such as insulin receptor substrate-1 and Erk1/2 in an IGF-I-independent manner. These results suggested that cinnamon extract is useful in antiaging treatment of skin.     

Purification and characterization of collagenolytic proteases from the hepatopancreas of northern shrimp (Pandalus eous)

Three gelatinolytic proteases (A1, A2, and B) were purified using a synthetic substrate, DNP-Pro-Gln-Gly-Ile-Ala-Gly-Gln-d-Arg, from the hepatopancreas of Northern shrimp (Pandalus eous) by several chromatographic steps involving hydroxyapatite column chromatography, gel filtration on Superdex75, and ion-exchange chromatography on a MonoQ column. Collagenolytic proteases A2 and B, but not protease A1, were demonstrated to digest native porcine type I collagen at 25 degrees C and pH 7.5. Further characterizations of these two collagenolytic proteases showed that the pH optimum of enzyme A2 against DNP-peptide was found to be 11, whereas that of enzyme B was 8.5. The optimum temperature ranged between 40 and 45 degrees C for both enzymes, although enzyme B appeared to be thermally more stable than enzyme A2 at pH 7.5. Both enzymes were strongly inhibited by PMSF and antipain, which suggests that they belong to collagenolytic serine proteases.     

Biochemical properties of black drum and sheepshead seabream skin collagen

Acid-soluble collagen (ASC) and pepsin solubilized collagen (PSC) were isolated from the skins of black drum (Pogonias cromis) and sheepshead seabream (Archosargus probatocephalus) harvested in the Gulf of Mexico coastal waters. The yields of ASCs on dry basis from black drum and sheepshead were estimated at 2.3 and 2.6%, and the yields of PSCs were 15.8 and 29.3%, respectively. Analyses of molecular weight profile, amino acid composition, and secondary structure showed that the skin collagens from both species were typical type-I collagen. The molecular mass of alpha(1) and alpha(2) subunits, as determined by SDS-PAGE using Tris-Acetate gels, was 127 kDa and 116 kDa, respectively. The amino acid composition of ASC and PSC for both species was closer to calf skin ASC than to cod skin ASC. Thermal denaturation temperatures, measured by melting point using circular dichroism, gave the following values: black drum ASC, 34.2 degrees C; sheepshead ASC, 34.0 degrees C; black drum PSC, 35.8 degrees C; sheepshead PSC, 34.3 degrees C. The literature value for the heat stability of calf skin collagen is 36.3 degrees C. The potentials of collagens from black drum and sheepshead skins in the functional food, healthcare, and pharmaceutical industries are discussed.     

Fibril assemblies in aqueous whey protein mixtures

Fibril formation in mixtures of whey proteins upon heating at pH 2 was investigated. Fibrils were found to coexist with other structures, such as spherulites. These spherulites consist of radially oriented fibrils. At total protein concentrations above 6 wt %, transparent gels were formed. Changing the ratio between the various whey proteins did not affect this gelation concentration as long as beta-lactoglobulin (beta-lg) was present, suggesting that beta-lg was dominant in the gelation. Pure alpha-lactalbumin and pure bovine serum albumin did not form fibrils, nor did they gel upon heating at pH 2 and 80 degrees C for up to 10 h. They did however induce a decrease in the beta-lg concentration needed for gel formation upon heating at pH 2. Our results suggest that beta-lg is the only fibril forming protein at the conditions used and that no mixed fibrils are formed.     

Elucidation of the effect of formaldehyde and lipids on frozen stored cod collagen by FT-Raman spectroscopy and differential scanning calorimetry

The effect of frozen storage (-10 and -30 degrees C), formaldehyde, and fish oil on collagen, isolated from cod muscle, was investigated. Salt- and acid-soluble collagen fractions as well as insoluble collagen indicated changes in solubility on frozen storage. Differential scanning calorimetry (DSC) showed a highly cooperative transition at 28.2 degrees C for isolated collagen. Changes in the thermodynamic properties of collagen were observed on frozen storage at -10 degrees C compared with the control at -30 degrees C because of changes in structure. In the presence of formaldehyde, there were no changes in the DSC collagen transition; however, in the presence of fish oil there was an increase in enthalpy and an extra peak was observed at 44.6 degrees C, indicating collagen-fish oil interaction. Structural changes resulted in a decrease in the solubility of collagen in salt and acid solution. FT-Raman spectra obtained for collagen at -10 degrees C and -30 degrees C confirmed the alteration of the conformation of collagen not only at -10 degrees C but also in the presence of formaldehyde and fish oil.     

Heat-induced gelation of chicken Pectoralis major myosin and beta-lactoglobulin

The denaturation, aggregation, and rheological properties of chicken breast muscle myosin, beta-lactoglobulin (beta-LG), and mixed myosin/beta-LG solutions were studied in 0.6 M NaCl, 0.05 mM sodium phosphate buffer, pH 7.0, during heating. The endotherm of a mixture of myosin and beta-LG was identical to that expected if the endotherm of each protein was overlaid on the same axis. The maximum aggregation rate (AR(max)) increased, and the temperature at the AR(max) (T(max)) and initial aggregation temperature (T(o)) decreased as the concentration of both proteins was increased. The aggregation profile of <0.5% myosin was altered by the presence of 0.25% beta-LG. Addition of 0.5-3.0% beta-LG decreased storage moduli of 1% myosin between 55 and 75 degrees C, but increased storage moduli (G') when heated to 90 degrees C and after cooling. beta-LG had no effect on the gel point of > or =1.0% myosin, but enhanced gel strength when heated to 90 degrees C and after cooling. After cooling, the G' of 1% myosin/2%beta-LG gels was about 1.7 times greater than that of gels prepared from 2% myosin/1% beta-LG.     

Preparation and dynamic viscoelasticity characterization of alkali-solubilized collagen from shark skin

Alkali-solubilized collagens, prepared by alkali-acid extraction and alkali direct extraction (abbreviated AASC and ALSC, respectively), were characterized by dynamic viscoelastic measurement of collagen solution (10 mg/mL). The optimum preparative conditions in terms of yield and polypeptide size are as follows: for the alkali-acid extraction, a pretreatment with 0.5 or 1 M NaOH containing 15% Na(2)SO(4) within 5 days at 20 degrees C followed by the subsequent acid extraction, and for the alkaline direct extraction, a treatment with 0.5 M NaOH containing 10% NaCl at 4 degrees C for 20-30 days. A major portion of the polypeptide sizes of AASC and ALSC is composed of alpha chains (alpha1 and alpha2). Dynamic viscoelasticity of collagen solution was measured as a function of temperature. AASC showed a greater contribution of elastic behavior rather than viscous behavior. On the contrary, ALSC exhibits a stronger viscous behavior than elastic behavior.     

Purification and characterization of lipase in buckwheat seed

To obtain basic information about enzymatic deterioration of buckwheat flour, triacylglycerol lipase (LIP; EC 3.1.1.3) was purified from buckwheat seed. The LIP consisted of two isozymes, LIP I and LIP II, and they were purified with purification folds of 60 and 143 with final specific activities of 0.108 and 0.727 mumol of fatty acid released per minute per milligram of protein at 30 degrees C using triolein as a substrate. Molecular weights were estimated to be 150 (LIP I) and 28.4 kDa (LIP I) by gel filtration and 171 (LIP I) and 26.5 kDa (LIP II) by SDS-PAGE. Optimal pHs of LIP activities were 3.0 (LIP I) and 6.0 (Lip II) using triolein as a substrate. Both LIP I and II reacted in the acidic pH range. Optimal temperatures were 30 (LIP I) and 40 degrees C (LIP II), and both LIP I and II were stable below 30 degrees C when p-nitrophenyl-laurate was used as a substrate. However, they were inactivated above 60 degrees C. On the other hand, when triolein was used as a substrate, optimal temperatures were 30 degrees C for both LIP I and II, and they retained 40% of their activity after a 4 h incubation of enzymes at 70 degrees C. LIP I and II had higher activity against triolein than monoolein or tri/monopalmitin. Most of the LIP activity was distributed in the embryo.     

Use of DSC to detect the heterogeneity of hydrothermal stability in the polyphenol-treated collagen matrix

The hydrothermal stability of the collagen matrixes treated with plant polyphenols (tannins) depends on not only the strength of the polyphenol-collagen interactions but also the distribution uniformity of polyphenolic molecules within the collagen fibrils. Traditional methods of uniformity tests rely heavily on the expertise of workers and are thus subjective. This paper describes a differential scanning calorimetry (DSC) study of the sheepskin collagen samples treated with hydrolyzable tannins, including two commercial tannins' extracts (chestnut and valonea), two pure ellagitannins (vescalagin and castalagin), and six synthetic gallotannins (di-galloyl-ethylene glycol (DGE), tri-galloyl-glycerol, tetra-galloyl-meso-erythritol, penta-galloyl-adonitol, penta-galloyl-glucose, and hexa-galloyl-ducitol). The collagen sample without polyphenol treatment and the sample treated with DGE showed a single sharp peak in their DSC thermogram with a full peak width at half height (fwhh) of 3-4 degrees C. The samples treated with other tannins all showed multiple peak DSC profiles with the fwhh of each peak at about 3-4 degrees C. These multiple peak profiles imply that in these polyphenol-treated samples, there is a distribution of collagen molecules having different hydrothermal stability. The results have demonstrated that DSC offers an objective method to detect the stability heterogeneity of collagen matrixes in the solid state, providing a useful tool for the leather industry to evaluate the uniformity of leather tanning.     

Characterization of a new Maillard type reaction product generated by heating 1-deoxymaltulosyl-glycine in the presence of cysteine

The reaction between Amadori compounds and cysteine was investigated. When 1-deoxymaltulosyl-glycine (glycyl-fructosyl-glucose) was heated at 100 degrees C with cysteine in a neutral aqueous solution, a novel intermediate composed of 1-deoxyosone and cysteine was detected. NMR and mass spectrometry studies revealed the structure of the isolated intermediate to be 7,8a-dihydroxy-4a-methyl-8-(alpha-d-glucopyranosyloxy)hexahydro-5-oxa-4-thia-1-azanaphthalene-2-carboxylic acid. This intermediate easily generated isomaltol and acetylfuran as volatile compounds in 1 mol/L HCl at 100 degrees C.     

Effect of oxazolidine E on collagen fibril formation and stabilization of the collagen matrix

Oxazolidine E, an aldehydic cross-linking agent, is used to impart hydrothermal stability to collagen. The purpose of this study was to investigate the exact nature of oxazolidine E induced cross-links with collagen by using synthetic peptides having sequence homology with collagen type I. Tandem mass spectrometry revealed the formation of methylol and Schiff-base adducts upon reaction of oxazolidine E with the peptides. This was confirmed by allowing the reaction to proceed under reducing conditions using cyanoborohydride. Mass spectrometry (MS)-MS analysis clearly showed interaction of tryptophan and lysine residues with oxazolidine E and demonstrated that arginine could be cross-linked with glycine in the presence of oxazolidine E through the formation of a methylene bridge. Collagen fibrils regenerated from monomers in the presence and absence of oxazolidine E were studied using atomic force microscopy to investigate morphological alterations. Regenerated fibrils showing the typical 65 nm D-banding pattern were obtained from those formed both in the presence and absence of oxazolidine E, and there was no evidence of a change in the D-periodicity of these fibrils. This indicated that oxazolidine E does not hinder collagen molecules from correctly aligning to form the quarter-stagger structure.     

Combined influence of NaCl and sucrose on heat-induced gelation of bovine serum albumin

The combined influence of a strongly interacting cosolvent (NaCl) and a weakly interacting cosolvent (sucrose) on the heat-induced gelation of bovine serum albumin (BSA) was studied. The dynamic shear rheology of 4 wt % BSA solutions containing 0 or 20 wt % sucrose and 0-200 mM NaCl was monitored as they were heated from 30 to 90 degrees C at 1.5 degrees C min(-)(1), held at 90 degrees C for 120 min, and then cooled back to 30 degrees C at -1.5 degrees C min(-)(1). The turbidity of the same solutions was monitored as they were heated from 30 to 95 degrees C at 1.5 degrees C min(-)(1) or held isothermally at 90 degrees C for 10 min. NaCl had a similar effect on BSA solutions that contained 0 or 20 wt % sucrose, with the gelation temperature decreasing and the final gel strength increasing with increasing salt concentration and the greatest changes occurring between 25 and 100 mM NaCl. Nevertheless, the presence of sucrose did lead to an increase in the gelation temperature and final gel strength and a decrease in the final gel turbidity. The impact of NaCl on gel characteristics was attributed primarily to its ability to screen electrostatic interactions between charged protein surfaces, whereas the impact of sucrose was attributed mainly to its ability to increase protein thermal stability and strengthen the attractive forces between proteins through a preferential interaction mechanism.     

Bacterial communities are more dependent on soil type than fertilizer type, but the reverse is true for fungal communities

The soil microbial community is strongly influenced by a wide variety of factors, such as soil characteristics and field management systems. In order to use biological indicators based on microbial community structure, it is very important to know whether or not these factors can be controlled. The present study aimed to determine whether soil type or fertilization has a greater influence on the soil microbial community based on denaturing gradient gel electrophoresis (DGGE) analysis of 12 experimental field plots containing four different soil types, Cumulic Andosol, Low-humic Andosol, Yellow Soil and Gray Lowland Soil, kept under three different fertilizer management systems since 2001 (the application of chemical fertilizer, the application of rice husk and cow manure, and the application of pig manure). Bacterial DGGE analysis using 16S rRNA genes and fungal DGGE analysis using 18S rRNA genes revealed that the bacterial community was related to the soil type more than the fertilization; however, the fungal community was related to the fertilization more than the soil type. These results might suggest that the fungal community is easier to control by fertilization than the bacterial community. Thus, we propose that indicators based on the fungal community might be more suitable as microbial indicators for soil quality.     

Quantitation of 3-aminopropionamide in potatoes-a minor but potent precursor in acrylamide formation

3-Aminopropionamide (3-APA) has recently been suggested as a transient intermediate in acrylamide (AA) formation during thermal degradation of asparagine initiated by reducing carbohydrates or aldehydes, respectively. 3-APA may also be formed in foods by an enzymatic decarboxylation of asparagine. Using a newly developed method to quantify 3-APA based on liquid chromatography/tandem mass spectrometry, it could be shown that the biogenic amine was present in several potato cultivars in different amounts. Further experiments indicated that 3-APA is formed during storage of intact potatoes (20 or 35 degrees C) or after crushing of the cells. The heating of 3-APA under aqueous or low water conditions at temperatures between 100 and 180 degrees C in model systems always generated more AA than in the same reaction of asparagine, thereby pointing to 3-APA as a very effective precursor of AA. While the highest yields measured were about 28 mol % in the presence of carbohydrates (170 degrees C; aqueous buffer), in the absence of carbohydrates, 3-APA was even converted by about 63 mol % into AA upon heating at 170 degrees C under aqueous conditions. Propanoic acid amides bearing an amino or hydroxy group in the alpha-position, such as 2-hydroxypropionamide and l-alaninamide, were ineffective in AA generation indicating that elimination occurs only from the beta-position.     

Gelation of chicken pectoralis major myosin and heat-denatured beta-lactoglobulin

Thermal, rheological, and microstructural properties of myosin (1 and 2% protein) were compared to mixtures of 1% myosin and 1% heat-denatured beta-lactoglobulin aggregates (myosin/HDLG) and 1% myosin and 1% native beta-lactoglobulin (myosin/beta-LG) in 0.6 M NaCl and 0.05 M sodium phosphate buffer, pH 6.0, 6.5, and 7.0 during heating to 71 degrees C. Thermal denaturation patterns of myosin and myosin/HDLG were similar except for the appearance of an endothermic peak at 54-56 degrees C in the mixed system. At pH 7.0, 2% myosin began to gel at 48 degrees C and had a storage modulus (G') of 500 Pa upon cooling. Myosin/HDLG (2% total protein) had a gel point of 48 degrees C and a G' of 650 Pa, whereas myosin/beta-LG had a gel point of 49 degrees C but the G' was lower (180 Pa). As the pH was decreased, the gel points of myosin and myosin/HDLG decreased and the G' after cooling increased. The HDLG was incorporated within the myosin gel network, whereas beta-LG remained soluble.     

Anti type I allergic property of Japanese butterbur extract and its mast cell degranulation inhibitory ingredients

Pollenosis is a disease that affects 1 in 10 of the Japanese population. During the season of cedar pollen dispersal, many patients suffer from symptoms such as sniffling, sternutation, and itching of the eyes. Japanese butterbur is a popular vegetable and is one of the few domestic vegetables in Japan. The anti type I allergic effects of an aqueous ethanol extract from aerial parts of Japanese butterbur (JBE) were evaluated in rats and RBL-2H3 mast cells. In the passive cutaneous anaphylaxis reaction in rats, a single oral treatment of JBE (1000 mg/kg) was found to suppress the reaction. In IgE-sensitized RBL-2H3 cells, JBE (10-100 microg/mL) inhibited beta-hexosaminidase release, leukotriene C(4)/D(4)/E(4) synthesis, and TNF-alpha production. Moreover, a high concentration of JBE (1000 microg/mL) suppressed smooth muscle constriction induced by histamine (10 microM) and leukotriene D(4) (10 nM) in a guinea pig trachea strip. The search for components in JBE with an inhibitory activity on mast cell degranulation was guided by inhibition of beta-hexsosaminidase release. Two eremophilane-type sesquiterpenes, six polyphenolic compounds, and two triterpene glycosides were isolated. Of these compounds, fukinolic acid, a principal polyphenol constituent, showed potent inhibitory activity (IC(50) value = 2.1 microg/mL). Consequently, On the basis of its inhibition of mast cell activation and direct smooth muscle reaction induced by released mediators, JBE was found to suppress the type I allergic reaction.     

Purification and biochemical properties of dipeptidyl peptidase I from porcine skeletal muscle

Dipeptidyl peptidase I (DPP I; EC 3.4.14.1) was purified from porcine skeletal muscle after several steps such as heat treatment, ammonium sulfate fractionation, gel filtration chromatography, and HPLC anion exchange chromatography. The purified enzyme showed a native molecular mass of approximately 200 kDa on Sephacryl S-200 column chromatography. Two protein bands of 65 and 42 kDa were obtained by SDS-PAGE, indicating its oligomeric nature. Maximum activity was reached at pH 5.5 and 55 degrees C. DPP I shared some common substrate specificities, both on synthetic derivatives and on real peptides, with porcine muscle DPP III. The enzyme required reducing agents for full activation, although the halide requirement was not proved. DPP I was inhibited by the assayed cysteine peptidase inhibitors except p-CMB. The serine peptidase inhibitor 3, 4-DCI also inhibited the enzyme as did the divalent cations Co(2+), Mn(2+), and Zn(2+). On the basis of its properties, DPP I may contribute to the generation of dipeptides during the processing of meat and/or meat products, including cooked ham.     

Purification and characterization of gelatinase-like proteinases from the dark muscle of common carp (Cyprinus carpio)

Gelatinolytic proteinases from common carp dark muscle were purified by 30-60% ammonium sulfate fractionation and a combination of chromatographic steps including ion exchange on DEAE-Sephacel, gel filtration on Sephacryl S-200, ion exchange on High-Q, and affinity on gelatin-Sepharose. The molecular masses of these proteinases as estimated by SDS-PAGE were 75, 67, and 64 kDa under nonreducing conditions. The enzymes revealed high activity at a slightly alkaline pH range, and their activities were investigated using gelatin as substrate. Metalloproteinase inhibitors, EDTA, EGTA, and 1,10-phenanthroline, almost completely suppressed the gelatinolytic activity, whereas other proteinase inhibitors did not show any inhibitory effect. Divalent metal ion Ca (2+) is essential for the gelatinolytic activity. Furthermore, these gelatinolytic proteinases hydrolyze native type I collagen effectively even at 4 degrees C, strongly suggesting their involvement in the texture softening of fish muscle during the post-mortem stage.