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Helias?A.?Udo?de?HaesEmail author Olivier?Jolliet Greg?Norris Konrad?Saur 《The International Journal of Life Cycle Assessment》2002,7(4):192-195
The conclusions about the development of the content of the LC Initiative are the following:
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– | A specific niche for the Life Cycle Initiative has developed, compared with the role of SETAC, the International Society of Industrial Ecology (ISIE) and ISO. |
– | The aims of the initiative have step by step been extended, by bringing the initiative at a world level, by including both LCI and LCIA, and by including a program on Life Cycle Management (LCM). |
– | In the LCM program due attention is to be given to other tools and approaches than quantitative LCA which are relevant for life-cycle thinking in general, and also to the other two dimensions of sustainability, i.e. the social and economic dimensions. |
– | A number of important questions regarding the scope of the initiative and the methodological set-up have been in-depth discussed, thus resulting in a clear basis for the technical content of work to come. |
– | Three definition studies will now be implemented which will define the work program for the three programs of the initiative; these studies will be finalised by the end of 2002. |
3.
The 16S rRNA mitochondrial gene was used to reconstruct the relationships among 10 heteronemertean species (subclass Heteronemertea, phylum Nemertea);Lineus ruberandL. viridisare represented by more than one specimen to assess intraspecific variation in these enigmatic species, and the analysis includes in total 14 terminal taxa incorporating one palaeonemertean species (Tubulanus annulatus) for outgroup rooting. The aligned sequences were subjected to maximum parsimony, maximum-likelihood, and neighbor-joining analyses to estimate the phylogenetic relationship of the species. The results were concordant from all analyses and indicate that neitherLineusnorMicruraare monophyletic taxa, and that there is no support from a phylogenetic point of view to establish the monotypic genusRiseriellus. 相似文献
4.
Fritsch RM Schneider G Saur D Scheibel M Schmid RM 《The Journal of biological chemistry》2007,282(31):22551-22562
The integrated stress response (ISR) integrates a broad range of environmental and endogenous stress signals to the phosphorylation of the alpha-subunit of eukaryotic translation initiation factor 2 (eIF2 alpha). Although intense or prolonged activation of this pathway is known to induce apoptosis, the molecular mechanisms coupling stress-induced eIF2 alpha phosphorylation to the cell death machinery have remained incompletely understood. In this study, we characterized apoptosis initiation in response to classical activators of the ISR (tunicamycin, UVC, elevated osmotic pressure, arsenite). We found that all applied stress stimuli activated a mitochondrial pathway of apoptosis initiation. Rapid and selective down-regulation of the anti-apoptotic BCL-2 family protein MCL-1 preceded the activation of BAX, BAK, and caspases. Stabilization of MCL-1 blocked apoptosis initiation, while cells with reduced MCL-1 protein content were strongly sensitized to stress-induced apoptosis. Stress-induced elimination of MCL-1 occurred with unchanged protein turnover and independently of MCL-1 mRNA levels. In contrast, stress-induced phosphorylation of eIF2 alpha at Ser(51) was both essential and sufficient for the down-regulation of MCL-1 protein in stressed cells. These findings indicate that stress-induced phosphorylation of eIF2 alpha is directly coupled to mitochondrial apoptosis regulation via translational repression of MCL-1. Down-regulation of MCL-1 enables but not enforces apoptosis initiation in stressed cells. 相似文献
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Saurí A Saksena S Salgado J Johnson AE Mingarro I 《The Journal of biological chemistry》2005,280(27):25907-25912
The current model for cell-to-cell movement of plant viruses holds that transport requires virus-encoded movement proteins that intimately associate with endoplasmic reticulum membranes. We have examined the early stages of the integration into endoplasmic reticulum membranes of a double-spanning viral movement protein using photocross-linking. We have discovered that this process is cotranslational and proceeds in a signal recognition particle-dependent manner. In addition, nascent chain photocross-linking to Sec61alpha and translocating chain-associated membrane protein reveal that viral membrane protein insertion takes place via the translocon, as with most eukaryotic membrane proteins, but that the two transmembrane segments of the viral protein leave the translocon and enter the lipid bilayer together. 相似文献
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Douglas R. Taylor Meaghan J. Saur Erika Adams 《Evolution; international journal of organic evolution》1999,53(4):1028-1036
There has been a proliferation of studies, in a variety of taxa, that have detected sex-linked or cytoplasmic genes that enhance their own transmission via sex-ratio distortion. One of the most important parameters influencing the dynamics of these elements is the magnitude of their transmission advantage. In many systems, the mechanism of sex-ratio distortion is to abort X- or Y-bearing gametes. With this mechanism, the transmission advantage associated with sex-ratio distortion is diminished when the production of male gametes limits offspring production or when competition among the gametes of different males is intense. In this study, we analyzed the outcome of pollen competition between males that produced different sex ratios in the dioecious plant, Silene alba, and estimated how the sex-ratio bias influenced the transmission properties of the sex chromosomes. We varied the intensity of pollen competition by controlling the quantity of pollen used in crosses and used a combination of single-male pollinations and pollen mixtures to evaluate the effects of multiple paternity. Paternity in pollen mixtures was estimated using allozymes. Sex-ratio bias was directly influenced by the quantity of pollen, but the magnitude of this effect was small. The relative performance of pollen from different males varied substantially, especially when there was multiple paternity. Specifically, males with biased sex ratios sired far fewer offspring of either sex in pollen mixtures. In crosses involving single males, however, these “sex-ratio” males produced the same number of offspring as other males, so the female bias caused a significant transmission advantage for X-linked genes. X-linked genes could enhance their transmission via sex-ratio distortion in Silene populations, but the magnitude of this transmission advantage will depend on the ecological circumstances that influence the opportunity for multiple paternity. 相似文献
9.
High levels of cyclic‐di‐GMP in plant‐associated Pseudomonas correlate with evasion of plant immunity
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Sebastian Pfeilmeier Isabel Marie‐Luise Saur John Paul Rathjen Cyril Zipfel Jacob George Malone 《Molecular Plant Pathology》2016,17(4):521-531
The plant innate immune system employs plasma membrane‐localized receptors that specifically perceive pathogen/microbe‐associated molecular patterns (PAMPs/MAMPs). This induces a defence response called pattern‐triggered immunity (PTI) to fend off pathogen attack. Commensal bacteria are also exposed to potential immune recognition and must employ strategies to evade and/or suppress PTI to successfully colonize the plant. During plant infection, the flagellum has an ambiguous role, acting as both a virulence factor and also as a potent immunogen as a result of the recognition of its main building block, flagellin, by the plant pattern recognition receptors (PRRs), including FLAGELLIN SENSING2 (FLS2). Therefore, strict control of flagella synthesis is especially important for plant‐associated bacteria. Here, we show that cyclic‐di‐GMP [bis‐(3′‐5′)‐cyclic di‐guanosine monophosphate], a central regulator of bacterial lifestyle, is involved in the evasion of PTI. Elevated cyclic‐di‐GMP levels in the pathogen Pseudomonas syringae pv. tomato (Pto) DC3000, the opportunist P. aeruginosa PAO1 and the commensal P. protegens Pf‐5 inhibit flagellin synthesis and help the bacteria to evade FLS2‐mediated signalling in Nicotiana benthamiana and Arabidopsis thaliana. Despite this, high cellular cyclic‐di‐GMP concentrations were shown to drastically reduce the virulence of Pto DC3000 during plant infection. We propose that this is a result of reduced flagellar motility and/or additional pleiotropic effects of cyclic‐di‐GMP signalling on bacterial behaviour. 相似文献
10.
Nyland Cecilia Askham Modahl Ingunn Saur Raadal Hanne Lerche Hanssen Ole Jørgen 《The International Journal of Life Cycle Assessment》2003,8(6):331-336
Aim, Scope and Background When materials are recycled they are made available for use for several future life cycles and can therefore replace virgin
material more than just once. In order to analyse the optimal waste management system for a given material, the authors have
analysed the material flows in a life cycle perspective. It is important to distinguish this approach for material flow analysis
for a given material from life cycle analysis of products. A product life cycle analysis analyses the product system from
cradle to grave, but uses some form of allocation in order to separate the life cycle of one product from another in cases
where component materials are recycled. This paper does not address allocation of burdens between different product systems,
but rather focuses on methodology for decision making for waste management systems where the optimal waste management system
for a given material is analysed. The focus here is the flow of the given material from cradle (raw material extraction) to
grave (the material, or its inherent energy, is no longer available for use). The limitation on the number of times materials
can be recycled is set by either the recycling rate, or the technical properties of the recycled material.
Main Features This article describes a mathematical geometric progression approach that can be used to expand the system boundaries and
allow for recycling a given number of times. Case studies for polyethylene and paperboard are used to illustrate the importance
of including these aspects when part of the Goal and Scope for the LCA study is to identify which waste management treatment
options are best for a given material. The results and discussion examine the different conclusions that can be reached about
which waste management option is most environmentally beneficial when the higher burdens and benefits of recycling several
times are taken into account.
Results In order to assess the complete picture of the burdens and benefits arising from recycling the system boundaries must be expanded
to allow for recycling many times. A mathematical geometric progression approach manages to take into account the higher burdens
and benefits arising from recycling several times. If one compares different waste management systems, e.g. energy recovery
with recycling, without expanding the system to include the complete effects of material recycling one can reach a different
conclusion about which waste management option is preferred.
Conclusions When the purpose of the study is to compare different waste management options, it is important that the system boundaries
are expanded in order to include several recycling loops where this is a physical reality. The equations given in this article
can be used to include these recycling loops. The error introduced by not expanding the system boundaries can be significant.
This error can be large enough to change the conclusions of a comparative study, such that material recycling followed by
incineration is a much better option than waste incineration directly.
Recommendations and Outlook When comparing waste management solutions, where material recycling is a feasible option, it is important to include the relevant
number of recycling loops to ensure that the benefits of material recycling are not underestimated. The methodology presented
in this article should be used in future comparative studies for strategic decision-making for waste management. The approach
should not be used for LCAs for product systems without due care, as this could lead to double counting of the benefits of
recycling (depending on the goal and scope of the analysis). For materials where the material cycle is more of a closed loop
and one cannot truly say that recycled materials replace virgin materials, a more sophisticated approach will be required,
taking into account the fact that recycled materials will only replace a certain proportion of virgin materials. 相似文献