GROWTH SUBSTANCE CURVATURES OF AVENA IN LIGHT AND DARK

An attempt has been made to analyze the base response, one of the light growth responses of Avena coleoptiles, by means of growth substance curvatures. The decrease in growth rate (first part of the base response) after exposure to light does not show if hetero-auxin is substituted for auxin-a (Sections 5, 6, and 10). This decreased growth after exposure very likely is due to an oxidative inactivation of auxin-a (Sections 8 and 9). Hetero-auxin can be inactivated too but in a much lesser degree than auxin-a (Section 9). The increase in growth rate following on the decreased growth (second part of the base response) is due to an increase in response of the plant to growth hormone which is independent of the type of hormone (Sections 1, 2, 7, 8, and 10). Under conditions of continuous exposure to light, however, the inactivation of the auxin-a under influence of the light is superimposed on this increased response to growth hormone. This inactivation can be eliminated from the light growth response by replacing the auxin-a by hetero-auxin. More detailed information on this subject can be found in Section 10. A review of the experiments and their results can be obtained from the scheme in Section 8. In Section 11 it is shown that light inhibits the formation of growth hormone in the decapitated coleoptile (regeneration). Very small amounts of light (25 m.c.s.) inhibit the regeneration markedly

The Apollo Nuclease Binds To TRF2 and Protects

Members of the β-CASP family of proteins are involved in DNA repair and RNA processing. We identified a member of this family of enzymes, hSNM1B/Apollo, in complex with the telomere binding proteins TRF2/Rap1. Due to its low abundance at telomeres, we consider Apollo to be a telomere accessory factor, and not part of the core telomere protein complex, shelterin. Apollo localizes to telomeres by interacting directly with the TRFH domain of TRF2. Structural analysis of this interaction revealed an interface in the TRFH domain of TRF2 that is predicted to be shared by numerous accessory factors recruited to the telomere by TRF2, in addition to Apollo. Disruption of the Apollo-TRF2 interaction by expressing an allele of Apollo that cannot bind to TRF2 (ApolloΔTRF2) or reducing the amount of endogenous Apollo in cells by RNAi resulted in deprotection of telomeres in S-phase, as evidenced by the presence of Telomere-dysfunction Induced Foci (TIFs). Additionally, Apollo-deficient telomeres have an aberrant signal seen by FISH that is more frequent after treatment with the DNA replication inhibitor, Aphidicolin. Together, the data are consistent with a role for Apollo during of after telomere replication. Isolation of the Apollo protein complex revealed that soluble Apollo is complexed in 1:1 stoichiometry with TRF2/Rap1, suggesting that Apollo might function primarily at telomeres. Additional components include DBC- 1, which interacts directly with Apollo and localizes to Cajal bodies, the translesion synthesis polymerase polη, and the homolgous recombination factor Rad51. The association of these proteins with Apollo suggests potential roles for Apollo in telomerase recruitment and formation of the protective t-loop structure at chromosome ends

Citizens contributing in landscape in the Netherlands

With the continuing loss of landscape elements and open space, landscape management is gaining importance in tandem with the design of acceptable private and voluntary financing arrangements. Here, we analyze the awareness, involvement, socio-demographic characteristics and the contribution of citizens regarding the landscape. The contribution of citizens has been classified into three fields of activities. Data analysis is based on a survey among 1.060 inhabitants in and around three designated peri-urban areas in the Netherlands. The results show that these areas are well known, albeit on a limited scale. Most of the stated willingness of the inhabitants to contribute to the landscape has been related with their socio-demographic characteristics and to a less extent with their involvement with the landscape. To increase the willingness of citizens to contribute to the landscape the communication strategy may be improved

Exotic Rickettsiae in Ixodes ricinus: fact or artifact?

Several pathogenic Rickettsia species can be transmitted via Ixodes ricinus ticks to humans and animals. Surveys of I. ricinus for the presence of Rickettsiae using part of its 16S rRNA gene yield a plethora of new and different Rickettsia sequences. Interpreting these data is sometimes difficult and presenting these findings as new or potentially pathogenic Rickettsiae should be done with caution: a recent report suggested presence of a known human pathogen, R. australis, in questing I. ricinus ticks in Europe. A refined analysis of these results revealed that R. helvetica was most likely to be misinterpreted as R. australis. Evidence in the literature is accumulating that rickettsial DNA sequences found in tick lysates can also be derived from other sources than viable, pathogenic Rickettsiae. For example, from endosymbionts, environmental contamination or even horizontal gene transfer

Cultivation of hitherto-uncultured bacteria belonging to the Verrucomicrobia subdivision 1 from the potato (Solanum tuberosum L.) rhizosphere

The role of dominant bacterial groups in the plant rhizosphere, e.g., those belonging to the phyla Acidobacteria and Verrucomicrobia, has, so far, not been elucidated, and this is mainly due to the lack of culturable representatives. This study aimed to isolate hitherto-uncultured bacteria from the potato rhizosphere by a combination of cultivation approaches. An agar medium low in carbon availability (oligotrophic agar medium) and either amended with potato root exudates or catalase or left unamended was used with the aim to improve the culturability of bacteria from the potato rhizosphere. The colony forming unit numbers based on colonies and microcolonies were compared with microscopically determined fluorescence-stained cell numbers. Taxonomical diversity of the colonies was compared with that of library clones made from rhizosphere DNA, on the basis of 16S rRNA gene comparisons. The oligotrophic media amended or not with catalase or rhizosphere extract recovered up to 33.6% of the total bacterial numbers, at least seven times more than the recovery observed on R2A. Four hitherto-uncultured Verrucomicrobia subdivision 1 representatives were recovered on agar, but representatives of this group were not found in the clone library. The use of oligotrophic medium and its modifications enabled the growth of colony numbers, exceeding those on classical agar media. Also, it led to the isolation of hitherto-uncultured bacteria from the potato rhizosphere. Further improvement in cultivation will certainly result in the recovery of other as-yet-unexplored bacteria from the rhizosphere, making these groups accessible for further investigation, e.g., with respect to their possible interactions with plants

Effect of bacterial inoculation, plant genotype and developmental stage on root-associated and endophytic bacterial communities in potato (Solanum tuberosum)

Beneficial bacteria interact with plants by colonizing the rhizosphere and roots followed by further spread through the inner tissues, resulting in endophytic colonization. The major factors contributing to these interactions are not always well understood for most bacterial and plant species. It is believed that specific bacterial functions are required for plant colonization, but also from the plant side specific features are needed, such as plant genotype (cultivar) and developmental stage. Via multivariate analysis we present a quantification of the roles of these components on the composition of root-associated and endophytic bacterial communities in potato plants, by weighing the effects of bacterial inoculation, plant genotype and developmental stage. Spontaneous rifampicin resistant mutants of two bacterial endophytes, Paenibacillus sp. strain E119 and Methylobacterium mesophilicum strain SR1.6/6, were introduced into potato plants of three different cultivars (Eersteling, Robijn and Karnico). Densities of both strains in, or attached to potato plants were measured by selective plating, while the effects of bacterial inoculation, plant genotype and developmental stage on the composition of bacterial, Alphaproteobacterial and Paenibacillus species were determined by PCR-denaturing gradient gel-electrophoresis (DGGE). Multivariate analyses revealed that the composition of bacterial communities was mainly driven by cultivar type and plant developmental stage, while Alphaproteobacterial and Paenibacillus communities were mainly influenced by bacterial inoculation. These results are important for better understanding the effects of bacterial inoculations to plants and their possible effects on the indigenous bacterial communities in relation with other plant factors such as genotype and growth stage

The Transnational Political Economy of Corporate Governance Regulation: A Research Outline

Corporate governance has become a buzzword of the global business community and is now receiving even wider attention given the repercussions of the Enron collapse. Although there is a burgeoning literature on this topic, the bulk of it is either highly normative or focused on corporate governance practices at the level of the firm. In contrast, our aim is to explain the current transformations of corporate governance regulation. Whereas this regulation used to be a distinctly national affair, it is now increasingly an area subject to both public and private (self-) regulation in multiple arenas, of which three are outstandingly important as well as closely interrelated and, therefore, form the empirical focus of the programme:- Europeanisation in the area of corporate governance regulation affects national regimes of corporate governance with a particular historical diversity, without entirely replacing them.- The EU, furthermore, does not operate in a vacuum but in a transatlantic and global context where it has to negotiate its choices with both state (mainly the US) and non-state actors. At the global level, private bodies such as the International Accounting Standards Board set many corporate governance standards, and international organisations like the OECD disseminate norms for good corporate governance.- Central and East European countries (CEEC) are exposed to the multiple (and partially conflicting) demands by global institutions and the EU when developing their corporat