Complexity untwined: The structure and function of cucumber (Cucumis sativus L.) shoot phloem

Cucurbit phloem is complex, with large sieve tubes on both sides of the xylem (bicollateral phloem), and extrafascicular elements that form an intricate web linking the rest of the vasculature. Little is known of the physical interconnections between these networks or their functional specialization, largely because the extrafascicular phloem strands branch and turn at irregular angles. Here, export in the phloem from specific regions of the lamina of cucumber (Cucumis sativus L.) was mapped using carboxyfluorescein and ¹⁴C as mobile tracers. We also mapped vascular architecture by conventional microscopy and X-ray computed tomography using optimized whole-tissue staining procedures. Differential gene expression in the internal (IP) and external phloem (EP) was analyzed by laser-capture microdissection followed by RNA-sequencing. The vascular bundles of the lamina form a nexus at the petiole junction, emerging in a predictable pattern, each bundle conducting photoassimilate from a specific region of the blade. The vascular bundles of the stem interconnect at the node, facilitating lateral transport around the stem. Elements of the extrafascicular phloem traverse the stem and petiole obliquely, joining the IP and EP of adjacent bundles. Using pairwise comparisons and weighted gene coexpression network analysis, we found differences in gene expression patterns between the petiole and stem and between IP and EP, and we identified hub genes of tissue-specific modules. Genes related to transport were expressed primarily in the EP while those involved in cell differentiation and development as well as amino acid transport and metabolism were expressed mainly in the IP.     

Effect of phospholipid vesicles on the activity of terminal transferase.

The terminal transferase activity is modified in the presence of lipid vesicles. A deep inhibitory effect takes place with phosphatidylserine and phosphatidylinositol, while some stimulation is present with sphingomyelin and almost no effect has been detected with phosphatidylethanolamine vesicles. These effects seem to be related to the charge properties of the lipid membranes.A possible involvement of phospholipids in the mechanism of action of the terminal transferase is suggested.     

Ecological Toxicity Methods and Metals. An examination of two case studies (8 pp + 1)

Goal, Scope and Background The Apeldoorn Workshop (April 15th, 2004, Apeldoorn, NL) brought together specialists in LCA and Risk Assessment to discuss current practices and complications of the life cycle impact assessment (LCIA) ecological toxicity (ecotox) methodologies for metals. The consensus was that the LCIA methods currently available do not appropriately characterize impacts of metals due to lack of fundamental metals chemistry in the models. A review of five methods available to perform ecotox impact assessment for metals has been prepared to provide Life Cycle Assessment (LCA) practitioners with a better understanding of the current state of the science and potential biases related to metals. The intent is to provide awareness on issues related to ecotox impact assessment. Methods In this paper two case studies, one a copper based product (copper tube), the other a zinc-based product (gutter systems), were selected and examined by applying freshwater ecological toxicity impact models – USES-LCA, Eco-indicator 99 (EI 99), IMPACT 2002, EDIP 97, and CalTOX-ETP. Both studies are recent, comprehensive, cradle-to-gate, and peer-reviewed. The objective is to review the LCIA results in the context of the practical concerns identified by the Apeldoorn Declaration, in particular illustrating any inconsistencies such as chemical characterization coverage, species specificity, and relative contribution to impact results. Results and Discussion The results obtained from all five of the LCIA methods for the copper tube LCI pointed to the same substance as being the most important – copper. This result was obtained despite major fundamental differences between the LCIA methods applied. However, variations of results were found when examining the freshwater ecological toxicity potential of zinc gutter systems. Procedural difficulties and inconsistencies were observed. In part this was due to basic differences in model nomenclature and differences in coverage (IMPACT 2002+ and EDIP 97 contained characterization factors for aluminium that resulted in 90% and 22% contribution to burden respectively, the other three methods did not). Differences were also observed relative to the emissions source compartment. In the case of zinc, air emissions were found to be substantial for some ecotox models, whereas, water emissions results were found to be of issue for others. Conclusions This investigation illustrates the need to proceed with caution when applying LCIA ecotox methodologies to life cycle studies that include metals. Until further improvements are made, the deficiencies should be clearly communicated as part of LCIA reporting. Business or policy decisions should not without further discussion be based solely on the results of the currently available methods for assessing ecotoxicity in LCIA. Outlook The outlook to remedy deficiencies in the ecological toxicity methods is promising. Recently, the LCIA Toxic Impacts Task Force of the UNEP/SETAC Life Cycle Initiative has formed a subgroup to address specific issues and guide the work towards establishment of sound characterization factors for metals. Although some measure of precision of estimation of potential impact has been observed, such as in the case of copper, accuracy is also a major concern and should be addressed. Further investigation through controlled experimentation is needed, particularly LCIs composed of a variety of inorganics as well as organics constituents. Support for this activity has come from the scientific community and industry as well. Broader aspects of structure and nomenclature are being collectively addressed by the UNEP/SETAC Life Cycle Initiative. These efforts will bring practical solutions to issues of naming conventions and LCI to LCIA flow assignments.     

An antiviral disulfide compound blocks interaction between arenavirus Z protein and cellular promyelocytic leukemia protein

The promyelocytic leukemia protein (PML) forms nuclear bodies (NB) that can be redistributed by virus infection. In particular, lymphocytic choriomeningitis virus (LCMV) influences disruption of PML NB through the interaction of PML with the arenaviral Z protein. In a previous report, we have shown that the disulfide compound NSC20625 has antiviral and virucidal properties against arenaviruses, inducing unfolding and oligomerization of Z without affecting cellular RING-containing proteins such as the PML. Here, we further studied the effect of the zinc-finger-reactive disulfide NSC20625 on PML-Z interaction. In HepG2 cells infected with LCMV or transiently transfected with Z protein constructs, treatment with NSC20625 restored PML distribution from a diffuse-cytoplasmic pattern to punctate, discrete NB which appeared identical to NB found in control, uninfected cells. Similar results were obtained in cells transfected with a construct expressing a Z mutant in zinc-binding site 2 of the RING domain, confirming that this Z-PML interaction requires the integrity of only one zinc-binding site. Altogether, these results show that the compound NSC20625 suppressed Z-mediated PML NB disruption and may be used as a tool for designing novel antiviral strategies against arenavirus infection.     

Using Interorganizational Information Systems to Support Environmental Management Efforts at ASG

We examine use of environmental information systems by ASG AB (hereafter ASG), an international logistics and transport firm headquartered in Stockholm, Sweden, as a case study to illustrate the role of information systems in life-cycle-oriented environmental management. This case provides an example of how a firm can use interorganizational information systems (IOISs) to move toward environmentally sustainable business practices. Through the use of IOISs, ASG has been able to improve its environmental performance and that of its suppliers. Further, this improved environmental performance has been a competitive advantage for ASG and enabled it to attract new business. As such, ASG's experiences illustrate how aggressive practices move environmental management beyond compliance and cost control, at which many firms have been successful, to revenue generation. The case also shows how environmentally sustainable business practices can be integrated into a firm's strategy. In addition to illustrating how ASG has used IOISs to improve environmental performance, we compare their use of environmental ISs with the expected evolution of environmental ISs presented in the Shaft and colleagues (1997) framework. Although some of ASG's experiences verify the expected progression of these types of systems, some developments are not as expected. These differences have implications for the framework.     

Highly Sensitive Assay for Measurement of Arenavirus-cell Attachment

Arenaviruses are a family of enveloped RNA viruses that cause severe human disease. The first step in the arenavirus life cycle is attachment of viral particles to host cells. While virus-cell attachment can be measured through the use of virions labeled with biotin, radioactive isotopes, or fluorescent dyes, these approaches typically require high multiplicities of infection (MOI) to enable detection of bound virus. We describe a quantitative (q)RT-PCR-based assay that measures Junin virus strain Candid 1 attachment via quantitation of virion-packaged viral genomic RNA. This assay has several advantages including its extreme sensitivity and ability to measure attachment over a large dynamic range of MOIs without the need to purify or label input virus. Importantly, this approach can be easily tailored for use with other viruses through the use of virus-specific qRT-PCR reagents. Further, this assay can be modified to permit measurement of particle endocytosis and genome uncoating. In conclusion, we describe a simple, yet robust assay for highly sensitive measurement of arenavirus-cell attachment.     

From Life Cycle Assessment to Life Cycle Management

Life cycle assessment (LCA) is a widely accepted methodology to support decision‐making processes in which one compares alternatives, and that helps prevent shifting of environmental burdens along the value chain or among impact categories. According to regulation in the European Union (EU), the movement of waste needs to be reduced and, if unavoidable, the environmental gain from a specific waste treatment option requiring transport must be larger than the losses arising from transport. The EU explicitly recommends the use of LCA or life cycle thinking for the formulation of new waste management plans. In the last two revisions of the Industrial Waste Management Programme of Catalonia (PROGRIC), the use of a life cycle thinking approach to waste policy was mandated. In this article we explain the process developed to arrive at practical life cycle management (LCM) from what started as an LCA project. LCM principles we have labeled the “3/3” principle or the “good enough is best” principle were found to be essential to obtain simplified models that are easy to understand for legislators and industries, useful in waste management regulation, and, ultimately, feasible. In this article, we present the four models of options for the management of waste solvent to be addressed under Catalan industrial waste management regulation. All involved actors concluded that the models are sufficiently robust, are easy to apply, and accomplish the aim of limiting the transport of waste outside Catalonia, according to the principles of proximity and sufficiency.     

Proteomic technologies and their application to pancreatic cancer

Pancreatic ductal adenocarcinoma is a devastating disease that represents an important health problem. It spreads rapidly at a time when patients have relatively few symptoms and consequently is often only detected at an advanced stage when treatment options are limited. Rapid developments in technology and bioinformatics have recently led to a surge in proteomics-based cancer research. Comparative analysis of protein profiles from nonmalignant and malignant pancreas cells or tissue, or from different stages of pancreatic cancer, potentially offer unique insight into the biology of this tumor type. Furthermore, proteomic approaches may provide novel diagnostic or therapeutic markers for this disease. Although such analyses are still in their infancy, they show great potential in the ongoing battle against this dismal disease.     

Differential expression of microRNAs in mouse embryonic bladder

MicroRNAs (miRNAs) are involved in several biological processes including development, differentiation and proliferation. Analysis of miRNA expression patterns in the process of embryogenesis may have substantial value in determining the mechanism of embryonic bladder development as well as for eventual therapeutic intervention. The miRNA expression profiles are distinct among the cellular types and embryonic stages as demonstrated by microarray technology and validated by quantitative real-time RT-PCR approach. Remarkably, the miRNA expression patterns suggested that unique miRNAs from epithelial and submucosal areas are responsible for mesenchymal cellular differentiation, especially regarding bladder smooth muscle cells. Our data show that miRNA expression patterns are unique in particular cell types of mouse bladder at specific developmental stages, reflecting the apparent lineage and differentiation status within the embryonic bladder. The identification of unique miRNAs expression before and after smooth muscle differentiation in site-specific area of the bladder indicates their roles in embryogenesis and may aid in future clinical intervention.