Amino acid sequence of the winged bean (Psophocarpus tetragonolobus) basic lectin. Adenine binding and identification of the active-site tryptophan residue

The complete amino acid sequence of winged bean basic agglutinin (WBA I) was obtained by a combination of manual and gas-phase sequencing methods. Peptide fragments for sequence analyses were obtained by enzymatic cleavages using trypsin and Staphylococcus aureus V8 endoproteinase and by chemical cleavages using iodosobenzoic acid, hydroxylamine, and formic acid. COOH-terminal sequence analysis of WBA I and other peptides was performed using carboxypeptidase Y. The primary structure of WBA I was homologous to those of other legume lectins and more so to Erythrina corallodendron. Interestingly, the sequence shows remarkable identities in the regions involved in the association of the two monomers of E. corallodendron lectin. Other conserved regions are the double metal-binding site and residues contributing to the formation of the hydrophobic cavity and the carbohydrate-binding site. Chemical modification studies both in the presence and absence of N-acetylgalactosamine together with sequence analyses of tryptophan-containing tryptic peptides demonstrate that tryptophan 133 is involved in the binding of carbohydrate ligands by the lectin. The location of tryptophan 133 at the active center of WBA I for the first time subserves to explain a role for one of the most conserved residues in legume lectins.

Humanitaarisuuden varjossa : Poliittiset tekijät lastensiirroissa Ruotsiin sotiemme aikana ja niiden jälkeen

The evacuation of Finnish children to Sweden during WW II has often been called a small migration . Historical research on this subject is scarce, considering the great number of children involved. The present research has applied, apart from the traditional archive research, the framework of history-culture developed by Rüsen in order to have an all-inclusive approach to the impact of this historical event. The framework has three dimensions: political, aesthetic and cognitive. The collective memory of war children has also been discussed. The research looks for political factors involved in the evacuations during the Winter War and the Continuation War and the post-war period. The approach is wider than a purely humanitarian one. Political factors have had an impact in both Finland and Sweden, beginning from the decision-making process and ending with the discussion of the unexpected consequences of the evacuations in the Finnish Parliament in 1950. The Winter War (30.11.1939 13.3.1940) witnessed the first child transports. These were also the model for future decision making. The transports were begun on the initiative of Swedes Maja Sandler, the wife of the resigned minister of foreign affairs Rickard Sandler, and Hanna Rydh-Munck af Rosenschöld , but this activity was soon accepted by the Swedish government because the humanitarian help in the form of child transports lightened the political burden of Prime Minister Hansson, who was not willing to help Finland militarily. It was help that Finland never asked for and it was rejected at the beginning. The negative response of Minister Juho Koivisto was not taken very seriously. The political forces in Finland supporting child transports were stronger than those rejecting them. The major politicians in support belonged to Finland´s Swedish minority. In addition, close to 1 000 Finnish children remained in Sweden after the Winter War. No analysis was made of the reasons why these children did not return home. A committee set up to help Finland and Norway was established in Sweden in 1941. Its chairman was Torsten Nothin, an influential Swedish politician. In December 1941 he appealed to the Swedish government to provide help to Finnish children under the authority of The International Red Cross. This plea had no results. The delivery of great amounts of food to Finland, which was now at war with Great Britain, had automatically caused reactions among the allies against the Swedish imports through Gothenburg. This included the import of oil, which was essential for the Swedish navy and air force. Oil was later used successfully to force a reduction in commerce between Sweden and Finland. The contradiction between Sweden´s essential political interests and humanitarian help was solved in a way that did not harm the country´s vital political interests. Instead of delivering help to Finland, Finnish children were transported to Sweden through the organisations that had already been created. At the beginning of the Continuation War (25.6.1941 27.4.1945) negative opinion regarding child transports re-emerged in Finland. Karl-August Fagerholm implemented the transports in September 1941. In 1942, members of the conservative parties in the Finnish Parliament expressed their fear of losing the children to the Swedes. They suggested that Finland should withdraw from the inter-Nordic agreement, according to which the adoptions were approved by the court of the country where the child resided. This initiative failed. Paavo Virkkunen, an influential member of the conservative party Kokoomus in Finland, favoured the so-called good-father system, where help was delivered to Finland in the form of money and goods. Virkkunen was concerned about the consequences of a long stay in a Swedish family. The risk of losing the children was clear. The extreme conservative party (IKL, the Patriotic Movement of the Finnish People) wanted to alienate Finland from Sweden and bring Finland closer to Germany. Von Blücher, the German ambassador to Finland, had in his report to Berlin, mentioned the political consequences of the child transports. Among other things, they would bring Finland and Sweden closer to each other. He had also paid attention to the Nordic political orientation in Finland. He did not question or criticize the child transports. His main interest was to increase German political influence in Finland, and the Nordic political orientation was an obstacle. Fagerholm was politically ill-favoured by the Germans, because he had a strong Nordic political disposition and had criticised Germany´s activities in Norway. The criticism of child transports was at the same time criticism of Fagerholm. The official censorship organ of the Finnish government (VTL) denied the criticism of child transports in January 1942. The reasons were political. Statements made by members of the Finnish Parliament were also censored, because it was thought that they would offend the Swedes. In addition, the censorship organ used child transports as a means of active propaganda aimed at improving the relations between the two countries. The Finnish Parliament was informed in 1948 that about 15 000 Finnish children still remained in Sweden. These children would stay there permanently. In 1950 the members of the Agrarian Party in Finland stated that Finland should actively strive to get the children back. The party on the left (SKDL, the Democratic Movement of Finnish People) also focused on the unexpected consequences of the child transports. The Social Democrats, and largely Fagerholm, had been the main force in Finland behind the child transports. Members of the SKDL, controlled by Finland´s Communist Party, stated that the war time authorities were responsible for this war loss. Many of the Finnish parents could not get their children back despite repeated requests. The discussion of the problem became political, for example von Born, a member of the Swedish minority party RKP, related this problem to foreign policy by stating that the request to repatriate the Finnish children would have negative political consequences for the relations between Finland and Sweden. He emphasized expressing feelings of gratitude to the Swedes. After the war a new foreign policy was established by Prime Minister (1944 1946) and later President (1946 1956) Juho Kusti Paasikivi. The main cornerstone of this policy was to establish good relations with the Soviet Union. The other, often forgotten, cornerstone was to simultaneously establish good relations with other Nordic countries, especially Sweden, as a counterbalance. The unexpected results of the child evacuation, a Swedish initiative, had violated the good relations with Sweden. The motives of the Democratic Movement of Finnish People were much the same as those of the Patriotic Movement of Finnish People. Only the ideology was different. The Nordic political orientation was an obstacle to both parties. The position of the Democratic Movement of Finnish People was much better than that of the Patriotic Movement of Finnish People, because now one could clearly see the unexpected results, which included human tragedy for the many families who could not be re-united with their children despite their repeated requests. The Swedes questioned the figure given to the Finnish Parliament regarding the number of children permanently remaining in Sweden. This research agrees with the Swedes. In a calculation based on Swedish population registers, the number of these children is about 7 100. The reliability of this figure is increased by the fact that the child allowance programme began in Sweden in 1948. The prerequisite to have this allowance was that the child be in the Swedish population register. It was not necessary for the child to have Swedish nationality. The Finnish Parliament had false information about the number of Finnish children who remained in Sweden in 1942 and in 1950. There was no parliamentary control in Finland regarding child transports, because the decision was made by one cabinet member and speeches by MPs in the Finnish Parliament were censored, like all criticism regarding child transports to Sweden. In Great Britain parliamentary control worked better throughout the whole war, because the speeches regarding evacuation were not censored. At the beginning of the war certain members of the British Labour Party and the Welsh Nationalists were particularly outspoken about the scheme. Fagerholm does not discuss to any great extent the child transports in his memoirs. He does not evaluate the process and results as a whole. This research provides some possibilities for an evaluation of this sort. The Swedish medical reports give a clear picture of the physical condition of the Finnish children when arriving in Sweden. The transports actually revealed how bad the situation of the poorest children was. According to Titmuss, similar observations were made in Great Britain during the British evacuations. The child transports saved the lives of approximately 2 900 children. Most of these children were removed to Sweden to receive treatment for illnesses, but many among the healthy children were undernourished and some suffered from the effects of tuberculosis. The medical inspection in Finland was not thorough. If you compare the figure of 2 900 children saved and returned with the figure of about 7 100 children who remained permanently in Sweden, you may draw the conclusion that Finland as a country failed to benefit from the child transports, and that the whole operation was a political mistake with far-reaching consequenses. The basic goal of the operation was to save lives and have all the children return to Finland after the war. The difficulties with the repatriation of the children were mainly psychological. The level of child psychology in Finland at that time was low. One may question the report by Professor Martti Kaila regarding the adaptation of children to their families back in Finland. Anna Freud´s warnings concerning the difficulties that arise when child evacuees return are also valid in Finland. Freud viewed the emotional life of children in a way different from Kaila: the physical survival of a small child forces her to create strong emotional ties to the person who is looking after her. This, a characteristic of all small children, occurred with the Finnish children too, and it was something the political decision makers in Finland could not see during and after the war. It is a characteristic of all little children. Yet, such experiences were already evident during the Winter War. The best possible solution had been to limit the child transports only to children in need of medical treatment. Children from large and poor families had been helped by organising meals and by buying food from Denmark with Swedish money. Assisting Finland by all possible means should have been the basic goal of Fagerholm in September 1941, when the offer of child transports came from Sweden. Fagerholm felt gratitude towards the Swedes. The risks became clear to him only in 1943. The war children are today a rather scattered and diffuse group of people. Emotionally, part of these children remained in Sweden after the war. There is no clear collective memory, only individual memories; the collective memory of the war children has partly been shaped later through the activities of the war child associations. The main difference between the children evacuated in Finland (for example from Karelia to safer areas with their families) and the war children, who were sent abroad, is that the war children lack a shared story and experience with their families. They were outsiders . The whole matter is sensitive to many of such mothers and discussing the subject has often been avoided in families. The war-time censorship has continued in families through silence and avoidance and Finnish politicians and Finnish families had to face each other on this issue after the war. The lack of all-inclusive historical research has also prevented the formation of a collective awareness among war children returned to Finland or those remaining permanently abroad.. Knowledge of historical facts will help war-children by providing an opportunity to create an all-inclusive approach to the past. Personal experiences should be regarded as part of a large historical entity shadowed by war and where many political factors were at work in both Finland and Sweden. This means strengthening of the cognitive dimension discussed in Rüsen´s all-inclusive historical approach.

Cloning,overexpression and purification of functionally active Saccharomyces cerevisiae Hop1 protein from scherichia coli

One of the major limitations to the application of high-resolution biophysical techniques such as X-crystallography and spectroscopic analyses to structure-function studies of Saccharomyces cerevisiae Hop1 protein has been the non-availability of sufficient quantities of functionally active pure protein. This has, indeed, been the case of many proteins, including yeast synaptonemal complex proteins. In this study, we have performed expression screening in Escherichia coli host strains, capable of high-level expression of soluble S. cerevisiae Hop1 protein. A new protocol has been developed for expression and purification of S. cerevisiae Hop1 protein, based on the presence of hexa-histidine tag and double-stranded DNA-Cellulose chromatography. Recombinant S. cerevisiae Hop1 protein was >98% pure and exhibited DNA-binding activity with high-affinity to the Holliday junction. The availability of the recombinant HOP1 expression vector and active Hop1 protein would facilitate structure-function investigations as well as the generation of appropriate truncated and site-directed mutant proteins, respectively. (C) 2010 Elsevier Inc. All rights reserved.

Pd and Pt ions as highly active sites for the water-gas shift reaction over combustion synthesized zirconia and zirconia-modified ceria

Noble metal substituted ionic catalysts were synthesized by solution combustion technique. The compounds were characterized by X-ray diffraction, FT-Raman spectroscopy, and X-ray photoelectron spectroscopy. Zirconia supported compounds crystallized in tetragonal phase. The solid solutions of ceria with zirconia crystallized in fluorite structure. The noble metals were substituted in ionic form.The water-gas shift reaction was carried out over the catalysts.Negligible conversions were observed with unsubstituted compounds. The substitution of a noble metal ion was found to enhance the reaction rate. Equilibrium conversion was obtained below 250 degrees C in the presence of Pt ion substituted compounds. The formation of Bronsted acid-Bronsted base pairs was proposed to explain the activity of zirconia catalysts. The effect of oxide ion vacancies on the reactions over substituted ceria-zirconia solid solutions was established. (c)2010 Elsevier B.V. All rights reserved.

Ultrasonic studies in chemically active liquid media (1) aqueous solution of N2O4

Using a pulse method the ultrasonic absorption has been studied in the frequency range of 2 to 10 Mc/s in dilute aqueous solutions of nitrogen tetroxide gas at room temperature. The absorption peaks (αλ vs frequency) observed in this study are attributed to the ionic dissociation reaction of the nitrous acid into its constituent ions. The rate constants of the forward and backward reactions are calculated using the theory of Tabuchi. The variation of the logarithm of the rate constant of the bimolecular ionic reaction, namely, log10 kb, with the square root of ionic strength qualitatively follows Brönsted's theory for ionic reactions in solutions.

Enzyme catalysed non-oxidative decarboxylation of aromatic acids II. Identification of active site residues of 2,3-dihydroxybenzoic acid decarboxylase from Aspergillus niger

In order to understand the mechanism of decarboxylation by 2,3-dihydroxybenzoic acid decarboxylase, chemical modification studies were carried out. Specific modification of the amino acid residues with diethylpyrocarbonate, N-bromosuccinimide and N-ethylmaleiimide revealed that at least one residue each of histidine, tryptophan and cysteine were essential for the activity. Various substrate analogs which were potential inhibitors significantly protected the enzyme against inactivation. The modification of residues at low concentration of the reagents and the protection experiments suggested that these amino acid residues might be present at the active site. Studies also suggested that the carboxyl and ortho-hydroxyl groups of the substrate are essential for interaction with the enzyme.

Active vibration suppression of beams with discrete actuators using optimal dynamic inversion

Most of the structural elements like beams, cables etc. are flexible and should be modeled as distributed parameter systems (DPS) to represent the reality better. For large structures, the usual approach of 'modal representation' is not an accurate representation. Moreover, for excessive vibrations (possibly due to strong wind, earthquake etc.), external power source (controller) is needed to suppress it, as the natural damping of these structures is usually small. In this paper, we propose to use a recently developed optinial dynamic inversion technique to design a set of discrete controllers for this purpose. We assume that the control force to the structure is applied through finite number of actuators, which are located at predefined locations in the spatial domain. The method used in this paper determines control forces directly from the partial differential equation (PDE) model of the system. The formulation has better practical significance, both because it leads to a closed form solution of the controller (hence avoids computational issues) as well as because a set of discrete actuators along the spatial domain can be implemented with relative ease (as compared to a continuous actuator).

Biochemical characterization of the intracellular domain of the human guanylyl cyclase C receptor provides evidence for a catalytically active homotrimer

Guanylyl cyclase C (GCC) is the receptor for the family of guanylin peptides and bacterial heat-stable enterotoxins (ST). The receptor is composed of an extracellular, ligand-binding domain and an intracellular domain with a region of homology to protein kinases and a guanylyl cyclase catalytic domain. We have expressed the entire intracellular domain of GCC in insect cells and purified the recombinant protein, GCC-IDbac, to study its catalytic activity and regulation. Kinetic properties of the purified protein were similar to that of full-length GCC, and high activity was observed when MnGTP was used as the substrate. Nonionic detergents, which stimulate the guanylyl cyclase activity of membrane-associated GCC, did not appreciably increase the activity of GCC-IDbac, indicating that activation of the receptor by Lubrol involved conformational changes that required the transmembrane and/or the extracellular domain. The guanylyl cyclase activity of GCC-IDbac was inhibited by Zn2+, at concentrations shown to inhibit adenylyl cyclase, suggesting a structural homology between the two enzymes. Covalent crosslinking of GCC-IDbac indicated that the protein could associate as a dimer, but a large fraction was present as a trimer. Gel filtration analysis also showed that the major fraction of the protein eluted at a molecular size of a trimer, suggesting that the dimer detected by cross-linking represented subtle differences in the juxtaposition of the individual polypeptide chains. We therefore provide evidence that the trimeric state of GCC is catalytically active, and sequences required to generate the trimer are present in the intracellular domain of GCC.

Diagnosis of dominant forcing factors for large-scale vertical velocities during active and break phases of the monsoon

An attempt to diagnose the dominant forcings which drive the large-scale vertical velocities over the monsoon region has been made by computing the forcings like diabatic heating fields,etc. and the large-scale vertical velocities driven by these forcings for the contrasting periods of active and break monsoon situations; in order to understand the rainfall variability associated with them. Computation of diabatic heating fields show us that among different components of diabatic heating it is the convective heating that dominates at mid-tropospheric levels during an active monsoon period; whereas it is the sensible heating at the surface that is important during a break period. From vertical velocity calculations we infer that the prime differences in the large-scale vertical velocities seen throughout the depth of the atmosphere are due to the differences in the orders of convective heating; the maximum rate of latent heating being more than 10 degrees Kelvin per day during an active monsoon period; whereas during a break monsoon period it is of the order of 2 degrees Kelvin per day at mid-tropospheric levels. At low levels of the atmosphere, computations show that there is large-scale ascent occurring over a large spatial region, driven only by the dynamic forcing associated with vorticity and temperature advection during an active monsoon period. However, during a break monsoon period such large-scale spatial organization in rising motion is not seen. It is speculated that these differences in the low-level large-scale ascent might be causing differences in convective heating because the weaker the low level ascent, the lesser the convective instability which produces deep cumulus clouds and hence lesser the associated latent heat release. The forcings due to other components of diabatic heating, namely, the sensible heating and long wave radiative cooling do not influence the large-scale vertical velocities significantly.

Active and break spells of the Indian summer monsoon

In this paper, we suggest criteria for the identification of active and break events of the Indian summer monsoon on the basis of recently derived high resolution daily gridded rainfall dataset over India (1951-2007). Active and break events are defined as periods during the peak monsoon months of July and August, in which the normalized anomaly of the rainfall over a critical area, called the monsoon core zone exceeds 1 or is less than -1.0 respectively, provided the criterion is satisfied for at least three consecutive days. We elucidate the major features of these events. We consider very briefly the relationship of the intraseasonal fluctuations between these events and the interannual variation of the summer monsoon rainfall. We find that breaks tend to have a longer life-span than active spells.While, almost 80% of the active spells lasted 3-4 days, only 40% of the break spells were of such short duration. A small fraction (9%) of active spells and 32% of break spells lasted for a week or longer. While active events occurred almost every year, not a single break occurred in 26% of the years considered. On an average, there are 7 days of active and break events from July through August. There are no significant trends in either the days of active or break events. We have shown that there is a major difference between weak spells and long intense breaks. While weak spells are characterized by weak moist convective regimes, long intense break events have a heat trough type circulation which is similar to the circulation over the Indian subcontinent before the onset of the monsoon. The space-time evolution of the rainfall composite patterns suggests that the revival from breaks occurs primarily from northward propagations of the convective cloud zone. There are important differences between the spatial patterns of the active/break spells and those characteristic of interannual variation, particularly those associated with the link to ENSO. Hence, the interannual variation of the Indian monsoon cannot be considered as primarily arising from the interannual variation of intraseasonal variation. However, the signature over the eastern equatorial Indian Ocean on intraseasonal time scales is similar to that on the interannual time scales.

A dragonfly inspired flapping wing actuated by electro active polymers

An energy-based variational approach is used for structural dynamic modeling of the IPMC (Ionic Polymer Metal Composites) flapping wing. Dynamic characteristics of the wing are analyzed using numerical simulations. Starting with the initial design, critical parameters which have influence on the performance of the wing are identified through parametric studies. An optimization study is performed to obtain improved flapping actuation of the IPMC wing. It is shown that the optimization algorithm leads to a flapping wing with dimensions similar to the dragonfly Aeshna Multicolor wing. An unsteady aerodynamic model based on modified strip theory is used to obtain the aerodynamic forces. It is found that the IPMC wing generates sufficient lift to support its own weight and carry a small payload. It is therefore a potential candidate for flapping wing of micro air vehicles.

Noise minimization in RC-active filters using generalized impedance converters

A procedure has been given for minimizing the total output noise of a Generalized Impedance Converter (GIC), subject to constraints dictated by signal handling capability of the Operational Amplifiers and ease of microcircuit fabrication. The noise reduction is achieved only by the adjustment of RC elements of the GIC, and the total output noise after optimization in the example cited is close to the theoretical lower limit. The output noise of a higher-order filter can be reduced by RC-optimizing the individual GIC's of the active realization. Experimental results on a 20–24 kHz channel bank band-pass filter demonstrate the effectiveness of the above procedure.

Steady-State Stability of Current Mode Active-Clamp ZVS DC-DC Converters

Active-clamp dc-dc converters are pulsewidth-modulated converters having two switches featuring zero-voltage switching at frequencies beyond 100 kHz. Generalized equivalent circuits valid for steady-state and dynamic performance have been proposed for the family of active-clamp converters. The active-clamp converter is analyzed for its dynamic behavior under current control in this paper. The steady-state stability analysis is presented. On account of the lossless damping inherent in the active-clamp converters, it appears that the stability region in the current-controlled active-clamp converters get extended for duty ratios, a little greater than 0.5, unlike in conventional hard-switched converters. The conventional graphical approach fails to assess the stability of current-controlled active-clamp converters due to the coupling between the filter inductor current and resonant inductor current. An analysis that takes into account the presence of the resonant elements is presented to establish the condition for stability. This method correctly predicts the stability of the current-controlled active-clamp converters. A simple expression for the maximum duty cycle for subharmonic free operation is obtained. The results are verified experimentally.