Film Formation and Structural Characterization of Silk of the Hornet Vespa simillima xanthoptera Cameron

2005 ◽  
Vol 60 (11-12) ◽  
pp. 906-914 ◽  
Author(s):  
Tsunenori Kameda ◽  
Katsura Kojima ◽  
Mitsuhiro Miyazawa ◽  
Seita Fujiwara

We extracted silk produced by the larva of the hornet Vespa simillima xanthoptera Cameron from its nest. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the extracted hornet silk showed four major components with molecular weights between 35 and 60 kDa. The main amino acid components of the hornet silk protein were Ala (33.5%), Ser (16.9%), Asp (8.5%) and Glu (8.1%). The hornet silk could be dissolved in hexafluoroisopropyl alcohol (HFIP) at 25 °C without incurring molecular degradation. A transparent film of hornet silk was obtained readily by the formation of a cast upon drying of the hornet silk in the HFIP solution. Residual HFIP solvent was removed from the film by extraction with pure water. Solid-state 13C NMR and FT-IR measurements revealed that the secondary structures of hornet silk proteins in the native state consisted of coexisting α-helix and β-sheet conformations. The β-sheet to α-helix ratio, which was changed by processing, was mainly responsible for the silk’s thermostability.

2000 ◽  
Vol 66 (1) ◽  
pp. 252-256 ◽  
Author(s):  
Katsuichi Saito ◽  
Kazuya Kondo ◽  
Ichiro Kojima ◽  
Atsushi Yokota ◽  
Fusao Tomita

ABSTRACT Streptomyces exfoliatus F3-2 produced an extracellular enzyme that converted levan, a β-2,6-linked fructan, into levanbiose. The enzyme was purified 50-fold from culture supernatant to give a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weights of this enzyme were 54,000 by SDS-PAGE and 60,000 by gel filtration, suggesting the monomeric structure of the enzyme. The isoelectric point of the enzyme was determined to be 4.7. The optimal pH and temperature of the enzyme for levan degradation were pH 5.5 and 60°C, respectively. The enzyme was stable in the pH range 3.5 to 8.0 and also up to 50°C. The enzyme gave levanbiose as a major degradation product from levan in an exo-acting manner. It was also found that this enzyme catalyzed hydrolysis of such fructooligosaccharides as 1-kestose, nystose, and 1-fructosylnystose by liberating fructose. Thus, this enzyme appeared to hydrolyze not only β-2,6-linkage of levan, but also β-2,1-linkage of fructooligosaccharides. From these data, the enzyme from S. exfoliatus F3-2 was identified as a novel 2,6-β-d-fructan 6-levanbiohydrolase (EC 3.2.1.64 ).


1983 ◽  
Vol 29 (10) ◽  
pp. 1361-1368 ◽  
Author(s):  
Thomas P. Poirier ◽  
Stanley C. Holt

Capnocytophaga ochracea acid (AcP; EC 3.1.3.2) and alkaline (AlP; EC 3.1.3.1) phosphatase was isolated by Ribi cell disruption and purified by sodium dodecyl sulphate – polyacrylamide gel electrophoresis (SDS–PAGE.) Both phosphatases eluted from Sephadex G-150 consistent with molecular weights (migration) of 140 000 and 110 000. SDS–PAGE demonstrated a 72 000 and 55 000 subunit molecular migration for AcP and AlP, respectively. The kinetics of activity of purified AcP and AIP on p-nitrophenol phosphate and phosphoseryl residues of the phosphoproteins are presented.


2019 ◽  
Vol 8 (3) ◽  
pp. 245-254
Author(s):  
Nia Lutfiana ◽  
◽  
Suharti Suharti ◽  
Evi Susanti ◽  
◽  
...  

The aim of this study was to characterize protease soluble collagen (PSC) obtained from milkfish scales, extraction using protease from proteolytic bacteria HTcUM7.1 isolate. The characterization included Fourier Transform Infra Red (FT-IR) spectra, Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) profile, Field Emission Scanning Electron Microscopy (FESEM), denaturation temperature by Differential Scanning Calorimetric (DSC) and solubility. The resulting PSC from milkfish scales has white color, fiber with a length of about 20-60 µm, FTIR spectra and SDS-PAGE profile showed that PSC was collagen Type I and denaturation temperature was 145.48 °C, with maximum solubility at pH 1-3 and 1-2 % NaCl. Its high denaturation temperature value allows the collagen to be applied in the fields of medicines and cosmetics.


Author(s):  
Preeti Anand ◽  
Jay Prakash Pandey ◽  
Dev Mani Pandey

Abstract Background Cocoonase is a proteolytic enzyme that helps in dissolving the silk cocoon shell and exit of silk moth. Chemicals like anhydrous Na2CO3, Marseille soap, soda, ethylene diamine and tartaric acid-based degumming of silk cocoon shell have been in practice. During this process, solubility of sericin protein increased resulting in the release of sericin from the fibroin protein of the silk. However, this process diminishes natural color and softness of the silk. Cocoonase enzyme digests the sericin protein of silk at the anterior portion of the cocoon without disturbing the silk fibroin. However, no thorough characterization of cocoonase and sericin protein as well as imaging analysis of chemical- and enzyme-treated silk sheets has been carried out so far. Therefore, present study aimed for detailed characterization of cocoonase and sericin proteins, phylogenetic analysis, secondary and tertiary structure prediction, and computational validation as well as their interaction with other proteins. Further, identification of tasar silkworm (Antheraea mylitta) pupa stage for cocoonase collection, its purification and effect on silk sheet degumming, scanning electron microscope (SEM)-based comparison of chemical- and enzyme-treated cocoon sheets, and its optical coherence tomography (OCT)-based imaging analysis have been investigated. Various computational tools like Molecular Evolutionary Genetics Analysis (MEGA) X and Figtree, Iterative Threading Assembly Refinement (I-TASSER), self-optimized predicted method with alignment (SOPMA), PROCHECK, University of California, San Francisco (UCSF) Chimera, and Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) were used for characterization of cocoonase and sericin proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), protein purification using Sephadex G 25-column, degumming of cocoon sheet using cocoonase enzyme and chemical Na2CO3, and SEM and OCT analysis of degummed cocoon sheet were performed. Results Predicted normalized B-factors of cocoonase and sericin with respect to α and β regions showed that these regions are structurally more stable in cocoonase while less stable in sericin. Conserved domain analysis revealed that B. mori cocoonase contains a trypsin-like serine protease with active site range 45 to 180 query sequences while substrate binding site from 175 to 200 query sequences. SDS-PAGE analysis of cocoonase indicated its molecular weight of 25–26 kDa. Na2CO3 treatment showed more degumming effect (i.e., cocoon sheet weight loss) as compared to degumming with cocoonase. However, cocoonase-treated silk cocoon sheet holds the natural color of tasar silk, smoothness, and luster compared with the cocoon sheet treated with Na2CO3. SEM-based analysis showed the noticeable variation on the surface of silk fiber treated with cocoonase and Na2CO3. OCT analysis also exemplified the variations in the cross-sectional view of the cocoonase and Na2CO3-treated silk sheets. Conclusions Present study enlightens on the detailed characteristics of cocoonase and sericin proteins, comparative degumming activity, and image analysis of cocoonase enzyme and Na2CO3 chemical-treated silk sheets. Obtained findings illustrated about use of cocoonase enzyme in the degumming of silk cocoon at larger scale that will be a boon to the silk industry.


1999 ◽  
Vol 181 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Hisayo Ono ◽  
Kazuhisa Sawada ◽  
Nonpanga Khunajakr ◽  
Tao Tao ◽  
Mihoko Yamamoto ◽  
...  

ABSTRACT 1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic β-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with l-glutamate. This enzyme required pyridoxal 5′-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25°C and had Km s of 9.1 mM forl-glutamate and 4.5 mM for dl-ASA. DABA acetyltransferase catalyzed acetylation of DABA to γ-N-acetyl-α,γ-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20°C in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15°C in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0.77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30°C.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Aleksandra M. Torbica ◽  
Jasna S. Mastilović ◽  
Milica M. Pojić ◽  
Žarko S. Kevrešan

The effects of wheat bug infestation (Eurygasterspp. andAeliaspp.) on the composition of wheat gluten proteins and its influence on flour technological quality were investigated in the present study. Wheat samples of six wheat varieties, collected from two localities in northern Serbia, were characterized by significantly different level of wheat bug infestation. Composition of wheat gluten proteins was determined using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE), while the selected parameters of technological quality were determined according to standard and modified empirical rheological methods (Farinograph, Extensograph, Alveograph, and Gluten Index). The surface morphology of the selected samples was viewed using scanning electron microscopy (SEM). Wheat from wheat bug-infested locality regardless of the variety had deteriorated technological quality expressed with higher Farinograph softening degree, lower or immeasurable Extensograph energy, and Alveograph deformation energy. The most important changes in the gluten proteins composition of bug-infested wheat were related to gliadin subunits with molecular weights below 75 kDa, which consequently caused deterioration of uniaxial and biaxial extensibility and dough softening during mixing.


Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1318 ◽  
Author(s):  
Bo Li ◽  
Jinbo Yao ◽  
Jiarong Niu ◽  
Jianyong Liu ◽  
Le Wang ◽  
...  

Much research has focused on improvement of the structural and mechanical properties of regenerated keratin materials by physical or chemical methods in recent years. In this research, regenerated keratin materials were modified with graphene oxide (GO). The properties of modified keratin films and the mechanism of interaction between GO and keratin macromolecules were studied. The SEM and XRD test results showed that the orientation of keratin macromolecules could be effectively improved by GO, which favored improvement of the keratin material’s crystallinity and made the films more uniform and compact. The thermal stability and mechanical properties of GO-modified keratin films were also improved significantly. At the same time, the reaction mechanism between keratin and GO materials was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), FT-IR, and Raman spectroscopy. It was shown that there was no chemical reaction between GO and keratin molecules, and the interaction between them was mainly via hydrogen bonding and van der Waals forces.


1983 ◽  
Vol 29 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Fraser E. Ashton ◽  
J. Alan Ryan ◽  
Colina Jones ◽  
Bernard R. Brodeur ◽  
Benito B. Diena

The distribution of serotypes among strains of Neisseria meningitidis responsible for a marked increase of meningitis cases in the Hamilton area, Ontario, in 1978 and 1979 was determined. Twenty-six serogroup B and two serogroup W135 strains isolated from cerebrospinal fluid, blood, and skin of 28 patients were serotyped by agar gel double diffusion. Twenty-one (81 %) of the group B strains were serotype 2b as judged by the formation of characteristic serotype precipitin bands with the specific anti-2996 (type 2b) serum. Fourteen of the serotype 2b strains also reacted with anti-77252 serum, which suggested that one strain or several closely related strains were mainly responsible for the increase in meningitis during the 2-year period. Examination of the outer membrane complexes (OMC) of the strains by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS–PAGE) revealed that all 21 of the serotype 2b strains contained the class 2 protein (molecular weight 41 500) which is known to be the site of the serotype 2b determinant. Further characterization of the serotype 2b,77252 strains by enzyme-linked immunosorbent assays (ELISA) and SDS–PAGE suggested that the 77252 determinant was present in the class 1 proteins of these strains. The serotype 2b containing strains were isolated from 77.7 and 70% of males and females, respectively, from 81.8% of children less than 5 years of age, and from 75.0% of patients of all age groups. The study indicates the important role of serotype 2b meningococci in causing the increased incidence of meningitis and further substantiates the important association of the serotype 2b determinant with group B serotype 2 meningococcal disease in Canada.


Blood ◽  
1990 ◽  
Vol 76 (5) ◽  
pp. 887-891 ◽  
Author(s):  
BP Schick

The relationship of protein synthesis to megakaryocyte maturation has been studied in guinea pigs in vivo. Guinea pigs were injected with a single dose of [35S]methionine. Megakaryocytes and platelets were isolated daily for 4 days, and proteins from both cells were isolated by DEAE-Sephacel chromatography and analyzed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and fluorography. All proteins in megakaryocytes corresponding to stained bands on the SDS- PAGE gels were radiolabeled at 3 hours after injection. The greatest loss of radioactivity from the megakaryocytes occurred between 1 and 3 days after injection. Only trace labeling of platelet proteins was seen at 3 hours, representing almost entirely three bands at molecular weights 47,000, 52,000, and 66,000. At 24 hours only about 13% of the maximal labeling was present, but not all proteins were labeled. The maximal labeling was at 3 days. The pattern of labeling of platelets at 3 days was identical to that of megakaryocytes at 3 hours. The protein pattern of nonmegakaryocytic marrow cells was different from that of the platelets and megakaryocytes. Data presented here suggest that most protein synthesis in megakaryocytes is completed at least 24 hours before release of the platelets to the circulation, and suggest some specificity in the proteins that are synthesized at the terminal stages of maturation.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
SATA YOSHIDA SRIE RAHAYU ◽  
WAHYU PRIHATINI

Abstract. Rahayu SYS, Prihatini W. 2020. Characterization of metallothionein protein from hepatopancreas organ of Pilsbryoconcha exilis collected from Cikaniki River, Western Java, Indonesia. Nusantara Bioscience 12: 1-5. Freshwater environment, undergoing various changes due to the presence of dangerous toxic anthropogenic waste. It causes pressure on the freshwater biota that lives in it, such as Pilsbryoconcha exilis mussel at the bottom of freshwater. This pressure is controlled by the body through the synthesis of a set of stress proteins. Endogenous proteins, metallothionein (MT), in the body of freshwater biota absorb heavy metals in the body of biota, in the form of stress control. This research identified MT protein on P. exilis from contaminated waters such as the Cikaniki river with the average of mercury levels in water, sediment, and hepatopancreas of mussels using AAS method were 0.001 mg/L, 0.120 mg/L, and 1.318 mg/L respectively. Hepatopancreas of P. exilis was extracted using a Tissue Extraction Reagent I kit (Invitrogen), with procedures following the factory manual. The extract was purified by filtration using Sephadec 50; then, the filtration results were migrated together with the PageRuler TM Unstained Low Range Protein Ladder (Fermentas) in Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS PAGE) gel medium on Biorad Protein II electrophoresis. After completion of electrophoresis, the gel was stained using Page Blue Protein Staining Solution (Fermentas), following the factory manual procedure. Characterization at this research has succeeded in obtaining the MT-I isoform protein measuring 5, 10, and 25 kDa from the hepatopancreas organ of P. exilis.


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