Studies on the tryptophan residues of soybean agglutinin. Involvement in saccharide binding

Modification of tryptophan side chains of soybean agglutinin (SBA) with N-bromosuccinimide results in a loss of the hemagglutinating and carbohydrate binding activities of the protein. One residue/subunit is probably essential for the binding activity. Modification leads to a large decrease in the fluorescene of the protein accompained by a blue shift. Iodide ion quenching of the protein fluorescence shows that saccharide binding results in a decreased accessibility of some of the tryptophan side chains. These results strongly point towards the involvement of tryptophan residues in the active site of SBA.

1-[(2-Chloro-3-quinolyl)methyl]indoline-2,3-dione

In the title compound, C18H11ClN2O2, the isatin and 2-chloro-3-methylquinoline units are both almost planar, with r.m.s.deviations of 0.0075 and 0.0086 angstrom, respectively, and the dihedral angle between the mean planes of the two units is 83.13 (7)degrees. In the crystal, a weak intermolecular C-H center dot center dot center dot O interaction links the molecules into chains along the c axis.

Main chain and segmental dynamics of semi interpenetrating based on polyisoprene and poly(methyl methacrylate)

Main chain and segmental dynamics of polyisoprene (PI) and poly(methyl methacrylate)(PMMA) chains in semi IPNs were systematically studied over a wide range of temperatures (above and below T-g of both polymers) as a function of composition, crosslink density, and molecular weight. The immiscible polymers retained most of its characteristic molecular motion; however, the semi IPN synthesis resulted in dramatic changes in the motional behavior of both polymers due to the molecular level interpenetration between two polymer chains. ESR spin probe method was found to be sensitive to the concentration changes of PMMA in semi IPNs. Low temperature spectra showed the characteristics of rigid limit spectra, and in the range of 293-373 K.complex spectra were obtained with the slow component mostly arisingout of the PMMA rich regions and fast component from the PI phase. We found that the rigid PMMA chains closely interpenetrated into thehighly mobile PI network imparts motional restriction in nearby PI chains, and the highly mobile PI chains induce some degree of flexibility in highly rigid PMMA chains. Molecular level interchain mixing was found to be more efficient at a PMMA concentration of 35 wt.%. Moreover, the strong interphase formed in the above mentionedsemi IPN contributed to the large slow component in the ESR spectra at higher temperature. The shape of the spectra along with the data obtained from the simulations of spectra was correlated to the morphology of the semi IPNs. The correlation time measurement detected the motional region associated with the glass transition of PI and PMMA, and these regions were found to follow the same pattern of shifts in a-relaxation of PI and PMMA observed in DMA analysis. Activation energies associated with the T-g regions were also calculated. T-50G was found to correlate with the T-g of PMMA, and the volume of polymer segments undergoing glass transitional motion was calculated to be 1.7 nm(3).C-13 T-1 rho measurements of PMMA carbons indicate that the molecular level interactions were strong in semi IPN irrespective of the immiscible nature of polymers. The motional characteristics of H atoms attached to carbon atoms in both polymers were analyzed using 2D WISE NMR. Main relaxations of both components shifted inward, and both SEM and TEM analysis showed the development of a nanometer sized morphology in the case of highly crosslinked semi IPN. (C) 2010 Elsevier Ltd. All rights reserved.

Enzymatic cross-linking of β-casein and its impact on digestibility and allergenicity

Protein modification via enzymatic cross-linking is an attractive way for altering food structure so as to create products with increased quality and nutritional value. These modifications are expected to affect not only the structure and physico-chemical properties of proteins but also their physiological characteristics, such as digestibility in the GI-tract and allergenicity. Protein cross-linking enzymes such as transglutaminases are currently commercially available, but also other types of cross-linking enzymes are being explored intensively. In this study, enzymatic cross-linking of β-casein, the most abundant bovine milk protein, was studied. Enzymatic cross-linking reactions were performed by fungal Trichoderma reesei tyrosinase (TrTyr) and the performance of the enzyme was compared to that of transglutaminase from Streptoverticillium mobaraense (Tgase). Enzymatic cross-linking reactions were followed by different analytical techniques, such as size exclusion chromatography -Ultra violet/Visible multi angle light scattering (SEC-UV/Vis-MALLS), phosphorus nuclear magnetic resonance spectroscopy (31P-NMR), atomic force (AFM) and matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS). The research results showed that in both cases cross-linking of β-casein resulted in the formation of high molecular mass (MM ca. 1 350 kg mol-1), disk-shaped nanoparticles when the highest enzyme dosage and longest incubation times were used. According to SEC-UV/Vis-MALLS data, commercial β-casein was cross-linked almost completely when TrTyr and Tgase were used as cross-linking enzymes. In the case of TrTyr, high degree of cross-linking was confirmed by 31P-NMR where it was shown that 91 % of the tyrosine side-chains were involved in the cross-linking. The impact of enzymatic cross-linking of β-casein on in vitro digestibility by pepsin was followed by various analytical techniques. The research results demonstrated that enzymatically cross-linked β-casein was stable under the acidic conditions present in the stomach. Furthermore, it was found that cross-linked β-casein was more resistant to pepsin digestion when compared to that of non modified β-casein. The effects of enzymatic cross-linking of β-casein on allergenicity were also studied by different biochemical test methods. On the basis of the research results, enzymatic cross-linking decreased allergenicity of native β-casein by 14 % when cross-linked by TrTyr and by 6 % after treatment by Tgase. It can be concluded that in addition to the basic understanding of the reaction mechanism of TrTyr on protein matrix, the research results obtained in this study can have high impact on various applications like food, cosmetic, medical, textile and packing sectors.

USING FLUORESCENT AND NON-FLUORESCENT STEROLS TO STUDY RAFTS AND INTRACELLULAR CHOLESTEROL TRANSPORT IN MAMMALIAN CELLS

Cholesterol is an essential component in the membranes of most eukaryotic cells, in which it mediates many functions including membrane fluidity, permeability and the formation of ordered membrane domains. In this work a fluorescent and a non-fluorescent cholesterol analog were characterized as tools to study cholesterol. Next, these analogs were used to study two specific cell biological processes that involve cholesterol, i.e. the structure and function of ordered membrane domains/rafts and intracellular cholesterol transport. The most common method for studying ordered membrane domains is by disrupting them by cholesterol depletion. Because cholesterol depletion affects many cellular functions besides those mediated by membrane domains, this procedure is highly unspecific. The cellular exchange of cholesterol by desmosterol as a tool to study ordered membrane domains was characterized. It turned out that the ability of desmosterol to form and stabilize membrane domains in vitro was weaker compared to cholesterol. This result was reinforced by atomistic scale simulations that indicated that desmosterol has a lower ordering effect on phospholipid acyl chains. Three procedures were established for exchanging cellular cholesterol by desmosterol. In cells in which desmosterol was the main sterol, insulin signaling was attenuated. The results suggest that this was caused by desmosterol destabilizing membrane rafts. Contrary to its effect on ordered membrane domains it was found that replacing cholesterol by desmosterol does not change cell growth/viability, subcellular sterol distribution, Golgi integrity, secretory pathway, phospholipid composition and membrane fluidity. Together these results suggest that exchanging cellular cholesterol by desmosterol provides a selective tool for perturbing rafts. Next, the importance of cholesterol for the structure and function of caveolae was analyzed by exchanging the cellular cholesterol by desmosterol. The sterol exchange reduced the stability of caveolae as determined by detergent resistance of caveolin-1 and heat resistance of caveolin-1 oligomers. Also the sterol exchange led to aberrations in the caveolar structure; the morphology of caveolae was altered and there was a larger variation in the amount of caveolin-1 molecules per caveola. These results demonstrate that cholesterol is important for caveolar stability and structural homogeneity. In the second part of this work a fluorescent cholesterol analog was characterized as a tool to study cholesterol transport. Tight control of the intracellular cholesterol distribution is essential for many cellular processes. An important mechanism by which cells regulate their membrane cholesterol content is by cholesterol traffic, mostly from the plasma membrane to lipid droplets. The fluorescent sterol probe BODIPY-cholesterol was characterized as a tool to analyze cholesterol transport between the plasma membrane, the endoplasmic reticulum (ER) and lipid droplets. The behavior of BODIPY-cholesterol was compared to that of natural sterols, using both biochemical and live-cell microcopy assays. The results show that the transport kinetics of BODIPY-cholesterol between the plasma membrane, the ER and lipid droplets is similar to that of unesterified cholesterol. Next, BODIPY-cholesterol was utilized to analyze the importance of oxysterol binding protein related proteins (ORPs) for cholesterol transport between the plasma membrane, the ER, and lipid droplets in mammalian cells. By overexpressing all human ORPs it turned out that especially ORP1S and ORP2 enhanced sterol transport from the plasma membrane to lipid droplets. Our results suggest that the increased sterol transport takes place between the plasma membrane and ER and not between the ER and lipid droplets. Simultaneous knockdown of ORP1S and ORP2 resulted in a moderate but significant inhibition of sterol traffic from the plasma membrane to ER and lipid droplets, suggesting a physiological role for these ORPs in this process. The two phenylalanines in an acidic tract (FFAT) motif in ORPs, which mediates interaction with vesicle associated membrane protein associated proteins (VAPs) in the ER, was not necessary for mediating sterol transport. However, VAP silencing slowed down sterol transport, most likely by destabilizing ORPs containing a FFAT motif.

The role of selected non-timber forest products for rural areas in Laos: Case studies in Ban Napo and Ban Kouay communities

Non-timber forest products (NTFPs) are one of the major income sources for the rural population of Laos. An exploratory study was conducted to determine the role of non-timber forest products for rural communities of the study area. The study was carried out in two villages viz. Ban Napo and Ban Kouay of Sangthong district between January and March 2010. A semi-structured questionnaire was used to gather data from the respondents. Twenty-five respondents from each village were chosen based on their involvement in NTFPs collection and marketing activities. Statistically significant NTFPs income differences were not found between the villages and age groups of the respondents, however, significant differences were found in the annual incomes between farms size of the respondents. This study also analyzed the value chain structure of the three (See khai’ ton, Bamboo mats and Incense sticks) important non-timber forest products and the interactions between the actors in the case study areas. Barriers to entry the market, governance and upgrading possibilities have been discussed for each of the value chains. Comparison of unit prices at different levels of the value chains indicated uneven income distribution in favour of the intermediaries, factories and foreign buyers. The lack of capital, marketing information and negotiation skills restricted the villagers to increase their income. However, all the respondents have shown their satisfaction with their income from NTFPs.

Chromatographic separation, fractionation and oxidation of selected beta-lactoglobulin peptides

The literature review elucidates the mechanism of oxidation in proteins and amino acids and gives an overview of the detection and analysis of protein oxidation products as well as information about ?-lactoglobulin and studies carried out on modifications of this protein under certain conditions. The experimental research included the fractionation of the tryptic peptides of ?-lactoglobulin using preparative-HPLC-MS and monitoring the oxidation process of these peptides via reverse phase-HPLC-UV. Peptides chosen to be oxidized were selected with respect to their amino acid content which were susceptible to oxidation and fractionated according to their m/z values. These peptides were: IPAVFK (m/z 674), ALPMHIR (m/z 838), LIVTQTMK (m/z 934) and VLVLDTDYK (m/z 1066). Even though it was not possible to solely isolate the target peptides due to co-elution of various fractions, the percentages of target peptides in the samples were satisfactory to carry out the oxidation procedure. IPAVFK and VLVLDTDYK fractions were found to yield the oxidation products reviewed in literature, however, unoxidized peptides were still present in high amounts after 21 days of oxidation. The UV data at 260 and 280 nm enabled to monitor both the main peptides and the oxidation products due to the absorbance of aromatic side-chains these peptides possess. ALPMHIR and LIVTQTMK fractions were oxidatively consumed rapidly and oxidation products of these peptides were observed even on day 0. High rates of depletion of these peptides were acredited to the presence of His (H) and sulfur-containing side-chains of Met (M). In conclusion, selected peptides hold the potential to be utilized as marker peptides in ?-lactoglobulin oxidation.

Safeguarding against new privacy threats in inter-enterprise collaboration environments

Inter-enterprise collaboration has become essential for the success of enterprises. As competition increasingly takes place between supply chains and networks of enterprises, there is a strategic business need to participate in multiple collaborations simultaneously. Collaborations based on an open market of autonomous actors set special requirements for computing facilities supporting the setup and management of these business networks of enterprises. Currently, the safeguards against privacy threats in collaborations crossing organizational borders are both insufficient and incompatible to the open market. A broader understanding is needed of the architecture of defense structures, and privacy threats must be detected not only on the level of a private person or enterprise, but on the community and ecosystem levels as well. Control measures must be automated wherever possible in order to keep the cost and effort of collaboration management reasonable. This article contributes to the understanding of the modern inter-enterprise collaboration environment and privacy threats in it, and presents the automated control measures required to ensure that actors in inter-enterprise collaborations behave correctly to preserve privacy.

Enhanced Ion Anisotropy by Nonconventional Coordination Geometry: Single-Chain Magnet Behavior for a [{(FeL)-L-II}(2){Nb-IV(CN)(8)}] Helical Chain Compound Designed with Heptacoordinate Fe-II

Nonconventional heptacoordination in combination with efficient magnetic exchange coupling is shown to yield a 1-D heteronuclear {(FeNbIV)-Nb-II} compound with remarkable magnetic features when compared to other Fe(II)-based single chain magnets (SCM). Cyano-bridged heterometallic {3d-4d} and {3d-5d} chains are formed upon assembling Fe(II) bearing a pentadentate macrocycle as the blocking ligand with octacyano metallates, [M(CN)(8)](4-) (M = Nb-IV, Mo-IV, W-IV.) X-ray diffraction (single-crystal and powder) measurements reveal that the [{(H2O)Fe(L-1)}{M(CN)(8)}{Fe(L-1)}](infinity) architectures consist of isomorphous 1-D polymeric structures based on the alternation of {Fe(L-1)}(2+) and {M(CN)(8)}(4-) units (L-1 stands for the pentadentate macrocycle). Analysis of the magnetic susceptibility behavior revealed cyano-bridged {Fe-Nb} exchange interaction to be antiferromagnetic with J = -20 cm(-1) deduced from fitting an Ising model taking into account the noncollinear spin arrangement. For this ferrimagnetic chain a slow relaxation of its magnetization is observed at low temperature revealing a SCM behavior with Delta/k(B) = 74 K and tau(0) = 4.6 x 10(-11) s. The M versus H behavior exhibits a hysteresis loop with a coercive field of 4 kOe at 1 K and reveals at 380 mK magnetic avalanche processes, i.e., abrupt reversals in magnetization as H is varied. The origin of these characteristics is attributed to the combination of efficient {Fe-Nb} exchange interaction and significant anisotropy of the {Fe(L-1)) unit. High field EPR and magnetization experiments have revealed for the parent compound [Fe(L-1)(H2O)(2)]Cl-2 a negative zero field splitting parameter of D approximate to -17 cm(-1). The crystal structure, magnetic behavior, and Mossbauer data for [Fe(L-1)(H2O)(2)]Cl-2 are also reported.

Enhanced Ion Anisotropy by Nonconventional Coordination Geometry: Single-Chain Magnet Behavior for a [{(FeL)-L-II}(2){Nb-IV(CN)(8)}] Helical Chain Compound Designed with Heptacoordinate Fe-II

Nonconventional heptacoordination in combination with efficient magnetic exchange coupling is shown to yield a 1-D heteronuclear {(FeNbIV)-Nb-II} compound with remarkable magnetic features when compared to other Fe(II)-based single chain magnets (SCM). Cyano-bridged heterometallic {3d-4d} and {3d-5d} chains are formed upon assembling Fe(II) bearing a pentadentate macrocycle as the blocking ligand with octacyano metallates, [M(CN)(8)](4-) (M = Nb-IV, Mo-IV, W-IV.) X-ray diffraction (single-crystal and powder) measurements reveal that the [{(H2O)Fe(L-1)}{M(CN)(8)}{Fe(L-1)}](infinity) architectures consist of isomorphous 1-D polymeric structures based on the alternation of {Fe(L-1)}(2+) and {M(CN)(8)}(4-) units (L-1 stands for the pentadentate macrocycle). Analysis of the magnetic susceptibility behavior revealed cyano-bridged {Fe-Nb} exchange interaction to be antiferromagnetic with J = -20 cm(-1) deduced from fitting an Ising model taking into account the noncollinear spin arrangement. For this ferrimagnetic chain a slow relaxation of its magnetization is observed at low temperature revealing a SCM behavior with Delta/k(B) = 74 K and tau(0) = 4.6 x 10(-11) s. The M versus H behavior exhibits a hysteresis loop with a coercive field of 4 kOe at 1 K and reveals at 380 mK magnetic avalanche processes, i.e., abrupt reversals in magnetization as H is varied. The origin of these characteristics is attributed to the combination of efficient {Fe-Nb} exchange interaction and significant anisotropy of the {Fe(L-1)) unit. High field EPR and magnetization experiments have revealed for the parent compound [Fe(L-1)(H2O)(2)]Cl-2 a negative zero field splitting parameter of D approximate to -17 cm(-1). The crystal structure, magnetic behavior, and Mossbauer data for [Fe(L-1)(H2O)(2)]Cl-2 are also reported.

Single-File Diffusion of Water Inside Narrow Carbon Nanorings

We use atomistic molecular dynamics (MD) simulations to study the diffusion of water molecules confined inside narrow (6,6) carbon nanorings. The water molecules form two oppositely polarized chains. It is shown that the effective interaction between these two chains is repulsive in nature. The computed mean-squared displacement (MSD) clearly shows a scaling with time similar to t(1/2), which is consistent with single-file diffusion (SFD). The time up to which the water molecules undergo SFD is shown to be the lifetime of the water molecules inside these chains. Simulations of "uncharged" water molecules inside the nanoring show the formation of several water chains and yield SFD. These observations conclusively prove that the diffusion is Fickian when there is a single chain of water and SFD is observed only when two or more chains are present.

Synthesis, structure, transformation studies and catalytic properties of open-framework cadmium thiosulfate compounds

Five new thiosulfate based inorganic-organic hybrid open-framework compounds have been synthesized employing mild reaction conditions. Of the five compounds, [Na-2(H2O)(8)][Cd(C10H8N2)( S2O3)(2)]center dot 2H(2)O, I and [Cd-2(C10H8N2)(2)(HS2O3)(2)(S2O3)(2)][(C10H9N2)(2)(C10H8N2)(2)]center dot 8H(2)O, II have one-dimensional (1D) structures and [Cd(C10H8N2)(H2O)(2)(S2O3)]center dot 2H(2)O, III, [Cd-2(C10H8N2)(3)(S2O3)(2)], IV and [Cd-2(C10H8N2)(2.5)(S2O3)(2)], V have three- dimensional (3D) structures. The 1D structures are somewhat related, formed by the bonding between tetrahedral Cd centers (CdN2S2) and 4,4'-bipyridine (bpy) units. The inter-chain spaces are occupied by the hanging thiosulfate units in both the cases along with Na(H2O)(6) chains in I and free bpy units in II. The three 3D structures have one-dimensional cadmium thiosulfate chains linked by bpy units. Interpenetration has been observed in all the 3D structures. The 3D structures appear to be related and can be derived from fgs net. Transformation studies on the 1D compound, [Na-2(H2O)(8)][Cd(C10H8N2)(S2O3)(2)]center dot 2H(2)O, I, indicated a facile formation of [Cd(C10H8N2)(H2O)(2)(S2O3)]center dot 2H(2)O, III. Prolonged heating of I gave rise to a 3D cadmium sulfate phase, [Cd-2(C10H8N2)(2)(H2O)(3)(SO4)(2)]center dot 2H(2)O, VI. Compound VI has one-dimensional cadmium sulfate chains formed by six-membered rings connected by bpy units to form a 3D structure, which appears to resemble the topological arrangement of III. Transformation studies of III indicates the formation of IV and V, and at a higher temperature a new 3D cadmium sulfate, [Cd(C10H8N2)(SO4)], VII. Compound VII has a 4 x 4 grid cadmium sulfate layers pillared by bpy units. All the compounds were characterized by PXRD, TGA, IR and UV-visible studies. Preliminary studies on the possible use of the 3D compounds (III-VII) in heterogeneous cyanosilylation of imines appear to be promising.

Determinants and Consequences of Information Sharing with Key Suppliers

As companies become more efficient with respect to their internal processes, they begin to shift the focus beyond their corporate boundaries. Thus, the recent years have witnessed an increased interest by practitioners and researchers in interorganizational collaboration, which promises better firm performance through more effective supply chain management. It is no coincidence that this interest comes in parallel with the recent advancements in Information and Communication Technologies, which offer many new collaboration possibilities for companies. However, collaboration, or any other type of supply chain integration effort, relies heavily on information sharing. Hence, this study focuses on information sharing, in particular on the factors that determine it and on its value. The empirical evidence from Finnish and Swedish companies suggests that uncertainty (both demand and environmental) and dependency in terms of switching costs and asset specific investments are significant determinants of information sharing. Results also indicate that information sharing improves company performance regarding resource usage, output, and flexibility. However, companies share information more intensely at the operational rather than the strategic level. The use of supply chain practices and technologies is substantial but varies across the two countries. This study sheds light on a common trend in supply chains today. Whereas the results confirm the value of information sharing, the contingent factors help to explain why the intensity of information shared across companies differ. In the future, competitive pressures and uncertainty are likely to intensify. Therefore, companies may want to continue with their integration efforts by focusing on the determinants discussed in this study. However, at the same time, the possibility of opportunistic behavior by the exchange partner cannot be disregarded.

Conflicts when Competitors Cooperate: Exploring Elements of Conflicts from a Business Network Perspective

Most of the existing research within the business network approach is based on companies that are operating on different levels within the same value chain, as a buyer and a supplier. Intercompetitor cooperation, i.e. cooperation between companies occupying the same level within different value chains, has not been studied to the same extent. Moreover scholars within the business network approach have usually described industrial relationships as long term, consisting of mutual commitment and trust. Industrial relationships are not static, but dynamic, and they contain situations of both harmony and conflict. There is consequently a need for more research both concerning intercompetitor cooperation and conflicts. The purpose of this study is to develop our theoretical and empirical understanding of the nature of conflicts in intercompetitor cooperation from a business network perspective. The focus of the study lies on issue and intensity of conflict. The issue of a conflict can be divided into cause and topic, while the intensity comprises the importance and outcome of a conflict. The empirical part of the study is based on two case studies of groups of cooperating competitors from two different industries. The applied research method is interviews. According to the findings of this study causes of conflicts in intercompetitor cooperation can be divided into three groups: focus, awareness and capacity. Topics of conflict can be related to domain, delivery, advertising or cooperation. Moreover the findings show that conflict situations may be grouped into not important, important or very important. Some conflicts may also be of varying importance, meaning that the importance varies from one point of time to another. Based on the findings of the study the outcome or status of a conflict can be analyzed both on a concrete and general level. The findings also indicate that several conflicts are partly hidden, which means that only one or some of the involved actors perceive the conflict. Furthermore several conflict situations can be related to external network actors.

(2-Chloro-8-methylquinolin-3-yl)methanol

The molecule of title compound, C11H10ClNO, is close to being planar (r.m.s deviation for the non-H atoms = 0.017 angstrom). In the crystal, molecules interact by way of O-H center dot center dot center dot O hydrogen bonds, generating C(2) chains propagating in [010]. The crystal structure is consolidated by C-H center dot center dot center dot pi interactions and aromatic pi-pi stacking interactions [centroid-centroid distance = 3.661 (2) angstrom].