Germination biology and occurrence of pol-yembryony in two forms of cats claw creeper vine, Dolichandra unguis-cati (Bignonia-ceae): implications for its invasiveness and management

Cat’s claw creeper, Dolichandra unguis-cati (L.) Lohmann (syn. Macfadyena unguis-cati (L.) Gentry) is a major environmental weed in Australia. Two forms (‘long’ and ‘short’ pod) of the weed occur in Australia. This investigation aimed to evaluate and compare germination behavior and occurrence of polyembryony in the two forms of the weed. Seeds were germinated in growth chambers set to 10/20 °C, 15/25 °C, 20/30 °C, 30/45 °C and 25 °C. Germination and polyembryony were monitored over a period of 12 weeks. For all the treatments in this study, seeds from the short pod form exhibited significantly higher germination rates and higher occurrence of polyembryony than those from the long pod form. Seeds from the long pod form did not germinate at the lowest temperature of 10/20 °C; in contrast, those of the short pod form germinated under this condition, albeit at a lower rate. Results from this study could explain why the short pod form of D. unguis-cati is the more widely distributed form in Australia, while the long pod form is confined to a few localities. The results have implication in predicting future ranges of both forms of the invasive D. unguis-cati, as well as inform management decisions for control of the weed.

Ion channel formation by zervamicin-IIB. A molecular modelling study.

Zervamicin-IIB (Zrv-IIB) is a 16 residue peptaibol which forms voltage-activated, multiple conductance level channels in planar lipid bilayers. A molecular model of Zrv-IIB channels is presented. The structure of monomeric Zrv-IIB is based upon the crystal structure of Zervamicin-Leu. The helical backbone is kinked by a hydroxyproline residue at position 10. Zrv-IIB channels are modelled as helix bundles of from 4 to 8 parallel helices surrounding a central pore. The monomers are packed with their C-terminal helical segments in close contact, and the bundles are stabilized by hydrogen bonds between glutamine 11 and hydroxyproline 10 of adjacent helices. Interaction energy profiles for movement of three different probes species (K+, Cl- and water) through the central pore are analyzed. The conformations of: (a) the sidechain of glutamine 3; (b) the hydroxyl group of hydroxyproline 10; and (c) the C-terminal hydroxyl group are "optimized" in order to maximize favourable interactions between the channel and the probes, resulting in favourable interaction energy profiles for all three. This suggests that conformational flexibility of polar sidechains enables the channel lining to mimic an aqueous environment.

Immigrant Associations in the Metropolitan Area of Finland : Forms of Mobilisation, Participation and Representation

This study examines the role of immigrant associations in the societal and political integration of immigrants into Finnish society. The societal focus is on the ability of immigrant associations to mobilise their ethnic group members to participate in the socio-economic, cultural and political domains of Finnish society and in certain cases even beyond. The political integrative aims are the opportunities of immigrant associations to participate and represent the interests of their ethnic group in local and national policy making. This study focuses on associations in the Metropolitan Area of Finland, (Espoo, Helsinki and Vantaa).The qualitative research consisted of 71 interviews conducted with members of immigrant associations and civil servants. These interviews were mainly semi-structured, including some additional open-ended questions. Additional data consisted of documents, planning reports and of follow-up enquiries. -- In the analysis of the data I categorised thirty-two immigrant associations according to the activity forms and the description of the goals by the members. The four categories consisted of integrative, societal, ethno-cultural and transnational immigrant associations. Most of the immigrant associations belonged to the integrative category (15 of 32 associations). On the one hand the aims of these associations are to provide access for their ethnic group members into Finnish society, while on the other to strengthen the ethnic identity of their members by organising ethno-cultural activities. The societal associations only focused on activities with the objective of including immigrants into the Finnish labour market and educational system. The goal of ethno-cultural associations was to strengthen the ethnic identity of their ethnic group members. The transnational associations aimed at improving the living conditions of women and children in the members' country of origin. The possibilities for immigrant associations to mobilise their members depends partly on external financing. Subsidies have been allocated for societal activities in particular. There remains a risk of the crowding out of ethno-cultural activities: something which has already taken place in several European countries. Immigrant associations aim to strengthen the identity of immigrants mainly by organising social and ethno-cultural activities. Another important target was to provide peer support and therapy courses. Additionally, immigrant women's associations offer assistance to women who have encountered violence by providing counselling and in some cases access to shelter. The data showed that there is an ever growing need to pay heed to the well-being of women, children and elderly immigrants. The participation of immigrant associations in the municipalities' integrative issues takes place mainly through cooperative projects. Until the end of the 1990s there had not been much cooperation. The problem with the projects was that they had mainly been managed by civil servants, whereas members from immigrant associations had remained in a more passive position. Representation of immigrant associations in councils has been fairly weak. Immigrant associations are included in the multicultural councils of Espoo and Vantaa, but only in the planning stages. The municipality of Helsinki does not include immigrant associations due to the large number of organisations which causes problems in finding fair, democratic representation. At the national level, the ‘Advisory Board for Ethnic Relations’ – ETNO didn’t chose its members based on membership of ethnic associations, but based on belongingness to one of the larger language groups spoken by the foreign population in Finland. Since ETNO’s third period (2005-2007), the representatives of immigrant associations and ethnic minority groups have been chosen from proposed candidates. Key words: immigrant associations, integration, mobilisation, participation, representation, the Metropolitan area of Finland, immigrant (women), civil servants

Suitability of a point-contact SAW-based stiffness transducer for biomedical applications

Methods of diagnosis in Biomedical applications can be broadly divided into contact and non-contact based methods. So far, ultrasound based methods have been found to be most favorable for non-contact, non-invasive diagnosis, especially in the case of tissue stiffness analysis. We report here, the fabrication and characterization details of a new contact based transducer system for qualitative determination of the stiffnesses of non-piezoelectric substrates using the phenomenon of Surface Acoustic Waves (SAW). Preliminary trials to study the functionality of this system were carried out on various metallic and non-metallic substrates, and the results were found to be satisfactory. To confirm the suitability of this system for biomedical applications, similar trials have been conducted on tissue mimicking phantoms with varying degrees of stiffness.

Solution structures of conformationally equilibrium forms of holo-acyl carrier protein (PfACP) from Plasmodium falciparum provides insight into the mechanism of activation of ACPs

Acyl Carrier Protein (ACP) from the malaria parasite, Plasmodium falciparum (PfACP) in its holo form is found to exist in two conformational states in solution. Unique 3D solution structures of holo-PfACP have been determined for both equilibrium conformations, using high-resolution NMR methods. Twenty high-resolution solution structures for each of the two forms of holo-PfACP have been determined on the basis of 1226 and 1218 unambiguously assigned NOEs (including NOEs between 4 '-phosphopantetheine prosthetic group (4 '-PP) and protein), 55 backbone dihedral angles and 26 hydrogen bonds. The atomic rmsd values of the determined structures of two equilibrium forms, about the mean coordinates of the backbone and heavy atoms, are 0.48 +/- 0.09 and 0.92 +/- 0.10 and 0.49 +/- 0.08 and 0.97 +/- 0.11 angstrom, respectively. The interaction of 4 '-PP with the polypeptide backbone is reported here for the first time for any of the ACPs. The structures of holo-PfACP consist of three well-defined helices that are tightly packed. The structured regions of the molecule are stabilized by extensive hydrophobic interactions. The difference between the two forms arises from a reorientation of the 4 '-PP group. The enthalpy difference between the two forms, although small, implies that a conformational switch is essential for the activation of holo-ACP. Sequence and structures of holo-PfACP have been compared with those of the ACPs from type I and type II fatty acid biosynthesis pathways (FAS), in particular with the ACP from rat and the butyryl-ACP from E. coli. The PfACP structure, thus determined has several novel features hitherto not seen in other ACPs.

Surface instability of confined elastic bilayers: Theory and simulations

The surface of a soft elastic film becomes unstable and forms a self-organized undulating pattern because of adhesive interactions when it comes in contact proximity with a rigid surface. For a single film, the pattern length scale lambda, which is governed by the minimization of the elastic stored energy, gives lambda similar to 3h, where h is the film thickness. Based on a linear stability analysis and simulations of adhesion and debonding, we consider the contact instability of an elastic bilayer, which provides greater flexibility in the morphological control of interfacial instability. Unlike the case of a single film, the morphology of the contact instability patterns, debonding distance, and debonding force in a bilayer can be controlled in a nonlinear way by varying the thicknesses and shear moduli of the films. Interestingly, the pattern wavelength in a bilayer can be greatly increased or decreased compared to a single film when the adhesive contact is formed by the stiffer or the softer of the two films, respectively. In particular, lambda as small as 0.5h can be obtained. This indicates a new strategy for pattern miniaturization in elastic contact lithography.

The Structure and Functions of Hantavirus Nucleocapsid Protein

Hantaviruses, members of the genus Hantavirus in the Bunyaviridae family, are enveloped single-stranded RNA viruses with tri-segmented genome of negative polarity. In humans, hantaviruses cause two diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS), which vary in severity depending on the causative agent. Each hantavirus is carried by a specific rodent host and is transmitted to humans through excreta of infected rodents. The genome of hantaviruses encodes four structural proteins: the nucleocapsid protein (N), the glycoproteins (Gn and Gc), and the polymerase (L) and also the nonstructural protein (NSs). This thesis deals with the functional characterization of hantavirus N protein with regard to its structure. Structural studies of the N protein have progressed slowly and the crystal structure of the whole protein is still not available, therefore biochemical assays coupled with bioinformatical modeling proved essential for studying N protein structure and functions. Presumably, during RNA encapsidation, the N protein first forms intermediate trimers and then oligomers. First, we investigated the role of N-terminal domain in the N protein oligomerization. The results suggested that the N-terminal region of the N protein forms a coiled-coil, in which two antiparallel alpha helices interact via their hydrophobic seams. Hydrophobic residues L4, I11, L18, L25 and V32 in the first helix and L44, V51, L58 and L65 in the second helix were crucial for stabilizing the structure. The results were consistent with the head-to-head, tail-to-tail model for hantavirus N protein trimerization. We demonstrated that an intact coiled-coil structure of the N terminus is crucial for the oligomerization capacity of the N protein. We also added new details to the head-to-head, tail-to-tail model of trimerization by suggesting that the initial step is based on interaction(s) between intact intra-molecular coiled-coils of the monomers. We further analyzed the importance of charged aa residues located within the coiled-coil for the N protein oligomerization. To predict the interacting surfaces of the monomers we used an upgraded in silico model of the coiled-coil domain that was docked into a trimer. Next the predicted target residues were mutated. The results obtained using the mammalian two-hybrid assay suggested that conserved charged aa residues within the coiled-coil make a substantial contribution to the N protein oligomerization. This contribution probably involves the formation of interacting surfaces of the N monomers and also stabilization of the coiled-coil via intramolecular ionic bridging. We proposed that the tips of the coiled-coils are the first to come into direct contact and thus initiate tight packing of the three monomers into a compact structure. This was in agreement with the previous results showing that an increase in ionic strength abolished the interaction between N protein molecules. We also showed that residues having the strongest effect on the N protein oligomerization are not scattered randomly throughout the coiled-coil 3D model structure, but form clusters. Next we found evidence for the hantaviral N protein interaction with the cytoplasmic tail of the glycoprotein Gn. In order to study this interaction we used the GST pull-down assay in combination with mutagenesis technique. The results demonstrated that intact, properly folded zinc fingers of the Gn protein cytoplasmic tail as well as the middle domain of the N protein (that includes aa residues 80 248 and supposedly carries the RNA-binding domain) are essential for the interaction. Since hantaviruses do not have a matrix protein that mediates the packaging of the viral RNA in other negatve stranded viruses (NSRV), hantaviral RNPs should be involved in a direct interaction with the intraviral domains of the envelope-embedded glycoproteins. By showing the N-Gn interaction we provided the evidence for one of the crucial steps in the virus replication at which RNPs are directed to the site of the virus assembly. Finally we started analysis of the N protein RNA-binding region, which is supposedly located in the middle domain of the N protein molecule. We developed a model for the initial step of RNA-binding by the hantaviral N protein. We hypothesized that the hantaviral N protein possesses two secondary structure elements that initiate the RNA encapsidation. The results suggest that amino acid residues (172-176) presumably act as a hook to catch vRNA and that the positively charged interaction surface (aa residues 144-160) enhances the initial N-RNA interacation. In conclusion, we elucidated new functions of hantavirus N protein. Using in silico modeling we predicted the domain structure of the protein and using experimental techniques showed that each domain is responsible for executing certain function(s). We showed that intact N terminal coiled-coil domain is crucial for oligomerization and charged residues located on its surface form a interaction surface for the N monomers. The middle domain is essential for interaction with the cytoplasmic tail of the Gn protein and RNA binding.

Analysis of multiple crystal forms of Bacillus subtilis BacB suggests a role for a metal ion as a nucleant for crystallization

Bacillus subtilis BacB is an oxidase that is involved in the production of the antibiotic bacilysin. This protein contains two double-stranded beta-helix (cupin) domains fused in a compact arrangement. BacB crystallizes in three crystal forms under similar crystallization conditions. An interesting observation was that a slight perturbation of the crystallization droplet resulted in the nucleation of a different crystal form. An X-ray absorption scan of BacB suggested the presence of cobalt and iron in the crystal. Here, a comparative analysis of the different crystal forms of BacB is presented in an effort to identify the basis for the different lattices. It is noted that metal ions mediating interactions across the asymmetric unit dominate the different packing arrangements. Furthermore, a normalized B-factor analysis of all the crystal structures suggests that the solvent-exposed metal ions decrease the flexibility of a loop segment, perhaps influencing the choice of crystal form. The residues coordinating the surface metal ion are similar in the triclinic and monoclinic crystal forms. The coordinating ligands for the corresponding metal ion in the tetragonal crystal form are different, leading to a tighter packing arrangement. Although BacB is a monomer in solution, a dimer of BacB serves as a template on which higher order symmetrical arrangements are formed. The different crystal forms of BacB thus provide experimental evidence for metal-ion-mediated lattice formation and crystal packing.

The Significance of Gender in the Prevalence, Forms and Perceptions of Workplace Bullying

Workplace bullying has been shown to have severe negative consequences for both the victims and organisations concerned. Thus, the aim of this paper is to further understanding of workplace bullying by in particular exploring the significance of gender in this phenomenon. The focus is on the prevalence, forms and perceptions of bullying, and the extent to which these interactions and perceptions can be understood as gendered. The aim of the paper is twofold: firstly, to describe gender differences in bullying in the male-dominated business world, and, secondly, to explain these differences by discussing how gender is linked to bullying and victimisation. It is argued that the higher prevalence rates reported by women can be seen as the result of an interaction between higher actual exposure rates to negative behaviours, lower perceived possibilities to defend themselves, and less reluctance to classify negative experiences as bullying, which all are mediated by perceptions of power.

Prevalence and Forms of Bullying among Business Professionals: A Comparison of Two Different Strategies for Measuring Bullying

The aim of this study was to analyse the prevalence and forms of workplace bullying among business professionals holding predominantly managerial or expert positions. A cross-sectional survey study was conducted among Finnish professionals with a university degree in business studies. In the study two different strategies for measuring bullying were used and compared. When provided a definition of bullying, 8.8% of the respondents reported that they had at least occasionally been bullied during the past 12 months. However, when using a slightly modified version of the Negative Acts Questionnaire (Einarsen & Hoel 2001), containing a list of 32 predefined negative and potentially harassing acts, as many as 24.1% of the respondents reported that they had been subjected to at least one of the negative acts on a weekly basis. The respondents had experienced predominantly work-related negative acts, e.g. that their opinions and views were ignored, that they were given unreasonable deadlines or that information was withheld. Although the prevalence rates reported with the two strategies varied considerably, there was still consistency between the two strategies in the sense that those who had classified themselves as bullied also reported higher exposure rates to almost all of the negative acts included.

The Critical Role of N- and C-Terminal Contact in Protein Stability and Folding of a Family 10 Xylanase under Extreme Conditions

Background: Stabilization strategies adopted by proteins under extreme conditions are very complex and involve various kinds of interactions. Recent studies have shown that a large proportion of proteins have their N- and C-terminal elements in close contact and suggested they play a role in protein folding and stability. However, the biological significance of this contact remains elusive. Methodology: In the present study, we investigate the role of N- and C-terminal residue interaction using a family 10 xylanase (BSX) with a TIM-barrel structure that shows stability under high temperature,alkali pH, and protease and SDS treatment. Based on crystal structure,an aromatic cluster was identified that involves Phe4, Trp6 and Tyr343 holding the Nand C-terminus together; this is a unique and important feature of this protein that might be crucial for folding and stabilityunder poly-extreme conditions. Conclusion: A series of mutants was created to disrupt this aromatic cluster formation and study the loss of stability and function under given conditions. While the deletions of Phe4 resulted in loss of stability, removal of Trp6 and Tyr343 affected in vivo folding and activity. Alanine substitution with Phe4, Trp6 and Tyr343 drastically decreased stability under all parameters studied. Importantly,substitution of Phe4 with Trp increased stability in SDS treatment.Mass spectrometry results of limited proteolysis further demonstrated that the Arg344 residue is highly susceptible to trypsin digestion in sensitive mutants such as DF4, W6A and Y343A, suggesting again that disruption of the Phe4-Trp6-Tyr343 (F-W-Y) cluster destabilizes the N-and C-terminal interaction. Our results underscore the importance of N- and C-terminal contact through aromatic interactions in protein folding and stability under extreme conditions, and these results may be useful to improve the stability of other proteins under suboptimal conditions.

New Solid State Forms of the Anti-HIV Drug Efavirenz. Conformational Flexibility and High Z ` Issues

Structural information on the solid forms of efavirenz, a non-nucleoside reverse transcriptase inhibitor, is limited, although various polymorphic forms of this drug have been patented. We report here structural studies of four new crystal forms a pure form, a cyclohexane solvate, and cocrystals with 1,4-cyclohexanedione and 4,4'-bipyridine. Temperature dependent single-crystal to single-crystal phase transitions are observed for the pure form and for the cyclohexane solvate with an increase in the number of symmetry independent molecules, Z', upon a lowering of temperature. Other issues related to these solid forms, such as thermal stability, conformational flexibility, and high Z' occurrences, are addressed by using a combined experimental and computational approach.

The Nature of Learning about Customers in a Customer Service Setting - A Study of Frontline Contact Persons

The starting point of this thesis is the notion that in order for organisations to understand what customers value and how customers experience service, they need to learn about customers. The first and perhaps most important link in an organisation-wide learning process directed at customers is the frontline contact person. Service- and sales organisations can only learn about customers if the individual frontline contact persons learn about customers. Even though it is commonly recognised that learning about customers is the basis for an organisation’s success, few contributions within marketing investigate the fundamental nature of the phenomenon as it occurs in everyday customer service. Thus, what learning about customers is and how it takes place in a customer-service setting is an issue that is neglected in marketing research. In order to explore these questions, this thesis presents a socio-cultural approach to understanding learning about customers. Hence, instead of considering learning equal to cognitive processes in the mind of the frontline contact person or learning as equal to organisational information processing, the interactive, communication-based, socio-cultural aspect of learning about customers is brought to the fore. Consequently, the theoretical basis of the study can be found both in socio-cultural and practice-oriented lines of reasoning, as well as in the fields of service- and relationship marketing. As it is argued that learning about customers is an integrated part of everyday practices, it is also clear that it should be studied in a naturalistic and holistic way as it occurs in a customer-service setting. This calls for an ethnographic research approach, which involves direct, first-hand experience of the research setting during an extended period of time. Hence, the empirical study employs participant observations, informal discussions and interviews among car salespersons and service advisors at a car retailing company. Finally, as a synthesis of theoretically and empirically gained understanding, a set of concepts are developed and they are integrated into a socio-cultural model of learning about customers.

An Experimental Study to Show the Effect of Thermal Stress on Thermal Contact Conductance at Sub-megapascal Contact Pressures

Experimental studies are presented to show the effect of thermal stresses on thermal contact conductance (TCC) at low contact pressures. It is observed that in a closed contact assembly, contact pressure acting on the interface changes with the changing temperature of contact members. This change in contact pressure consequently causes variations in the TCC of the junction. A relationship between temperature change and the corresponding magnitude of developed thermal stress in a contact assembly is determined experimentally. Inclusion of a term called temperature dependent load correction factor is suggested in the theoretical model for TCC to make it capable of predicting TCC values more accurately in contact assemblies that experience large temperature fluctuations. [DOI: 10.1115/1.4001615]