Coral bleaching is linked to the capacity of the animal host to supply essential metals to the symbionts

Massive coral bleaching events result in extensive coral loss throughout the world. These events are mainly caused by seawater warming, but are exacerbated by the subsequent decrease in nutrient availability in surface waters. It has therefore been shown that nitrogen, phosphorus or iron limitation contribute to the underlying conditions by which thermal stress induces coral bleaching. Generally, information on the trophic ecology of trace elements (micronutrients) in corals, and on how they modulate the coral response to thermal stress is lacking. Here, we demonstrate for the first time that heterotrophic feeding (i.e. the capture of zooplankton prey by the coral host) and thermal stress induce significant changes in micro element concentrations and isotopic signatures of the scleractinian coral Stylophora pistillata. The results obtained first reveal that coral symbionts are the major sink for the heterotrophically acquired micronutrients and accumulate manganese, magnesium and iron from the food. These metals are involved in photosynthesis and antioxidant protection. In addition, we show that fed corals can maintain high micronutrient concentrations in the host tissue during thermal stress and do not bleach, whereas unfed corals experience a significant decrease in copper, zinc, boron, calcium and magnesium in the host tissue and bleach. In addition, the significant increase in δ⁶⁵Cu and δ⁶⁶Zn signature of symbionts and host tissue at high temperature suggests that these isotopic compositions are good proxy for stress in corals. Overall, present findings highlight a new way in which coral heterotrophy and micronutrient availability contribute to coral resistance to global warming and bleaching.     

Letter to the Editors

–We have previously shown that NAD kinase and NADP phosphatase activities display circadian rhythms, in the soluble (SN) and membrane-bound (P) fractions of crude extracts of the achlorophyllous ZC mutant of the phytoflagellate Euglena gracilis (which displays circadian rhythmicity of cell division). We determined if changes in the affinity of NADP phosphatase and NAD kinase for their substrates, NADP⁺ and NAD⁺, were occurring by calculating the ratios 100(velocity found in Km conditions/velocity found in saturating conditions). The rationale was that if the affinity remained unchanged according to circadian time (CI), these values should always equal 50, independently of any changes in enzyme quantity; values greater than 50 should indicate increases in enzyme affinity, and values less than 50 decreases in affinity. Our results indicated that these values calculated for NADP phosphatase exhibited a complex pattern of rhythmicity, while those for NAD kinase displayed circadian variations strongly correlated with the rhythms in enzyme activity. The curves showed troughs at CT 00–04 both in dividing and nondividing cells and peaks at CT 18–20 or at CT 08–14 in cells sampled, respectively, from a dividing or a stationary culture. Such variations are indicative of changes in the kinetic properties of the enzyme, which may reflect modifications in its affinity either for effectors (such as Ca2⁺-calmodulin) or for its substrate, NAD⁺. This may be due to (i) the expression of different isoenzymes at different CTs; (ii) different posttranslational modifications of the enzyme; or (iii) concentrations of effectors varying in a circadian manner.     

Letters to the editor

A decrease in salinity and temperature over the past 3000 years has presented the marine algae of the Baltic Sea with very considerable problems in adaptation. The effects of salinity upon a number of Baltic algae have been measured. The results showed cell mortality to be severe in 0, 68 and 102‰, and minimal in 6 and 11‰: there was most variation in tolerance to 34 and 51‰. The salt tolerances of Baltic marine algae have proved more hyposaline than those of British intertidal algae. Water uptake and loss in tissues of Chorda filum and Fucus vesiculosus from Baltic and British populations have been measured in response to salinity changes. The results revealed significant population differences in both live and killed tissues. Receptacle development and oogonial maturation have been observed in Baltic and British F. vesiculosus, and found to differ in seasonality. Some observations were associated with local sea temperatures but differences in the timing of receptacle initiation and in oogonial size were not. Th depauperate thallus, commonly ascribed to the effects of low salinity, was found to be a complicated phenomenon, comprising numerous attributes which are combined differently in different taxa. The morphological differences between Baltic and British marine algae were usually striking.

The marine algae of the Baltic Sea have therefore diverged in a number of ways from their N. Atlantic counterparts. The naturally high variability of these taxa has enabled them to survive the period of increasingly strong selection pressure which followed the Littorina Sea episode. Divergence seems not to have advanced to the point where speciation may be said to have occurred. The Baltic may therefore be contrasted with the much older Mediterranean Sea, which contains a large number of endemic species. Nevertheless, the Baltic is a site of very considerable evolutionary importance.     

Connecting the Retina to the Brain

The visual system is beautifully crafted to transmit information of the external world to visual processing and cognitive centers in the brain. For visual information to be relayed to the brain, a series of axon pathfinding events must take place to ensure that the axons of retinal ganglion cells, the only neuronal cell type in the retina that sends axons out of the retina, find their way out of the eye to connect with targets in the brain. In the past few decades, the power of molecular and genetic tools, including the generation of genetically manipulated mouse lines, have multiplied our knowledge about the molecular mechanisms involved in the sculpting of the visual system. Here, we review major advances in our understanding of the mechanisms controlling the differentiation of RGCs, guidance of their axons from the retina to the primary visual centers, and the refinement processes essential for the establishment of topographic maps and eye-specific axon segregation. Human disorders, such as albinism and achiasmia, that impair RGC axon growth and guidance and, thus, the establishment of a fully functioning visual system will also be discussed.     

RNA kink turns to the left and to the right

A helix-loop-helix within the group I intron has most of the canonical sequence elements of a kink turn (K-turn), yet it bends in the opposite direction. The reverse K-turn kinks toward the major rather than the minor grooves of the flanking helices. This suggests that there are two distinct subclasses of tertiary structures that a K-turn secondary structure can adopt. The final structure may be specified by external factors, such as protein binding or the tertiary structural context, rather than the intrinsic conformation of the RNA.     

Improvement to the air-injection technique to estimate xylem vulnerability to cavitation

Several techniques have been developed to quantify the degree of embolism of the xylem using hydraulic conductance. Although there have been several improvements to these techniques, their reliability is still questionable and many technical pitfalls persist. We are proposing here a manometric approach to improve the accuracy of xylem cavitation measurement by the original air-injection technique which uses twigs exposed to pressurized air to cause cavitation. The measured parameter is air bubble production (P _b) caused by xylem cavitation in birch (Betula pendula Roth) twigs from which the percent increase in bubble production is calculated to quantify xylem cavitation. Data produced by three different methods (bench-drying, air-injection, and manometric approach) are compared. Xylem vulnerability curves (VCs) constructed by the reference and reliable bench-drying technique and the manometric approach show similar sigmoid “S” shape, but a small anomaly appeared in the VC constructed by the original air-injection technique. The xylem pressure inducing 50% of embolism (P ₅₀) was the same with the three techniques. Furthermore, there was a strong positive correlation between the estimators of xylem cavitation measured by the three different methods. For its reliability, precision and ease we recommend the manometric technique as an improved version of the original hydraulic air-injection method.     

Open the doors to the public to promote support

The author recently wrote about the animal use/animal rights battle and the increasing violence on the part of animal rights activists. He recounts being an outsider learning about the field and the issues at hand, lending insight into how the LAS field might better communicate with the communicators.     

It takes two to tango to the melanosome

The role of clathrin adaptor proteins in sorting cargo in the biosynthetic and recycling routes is an area of intense research. In this issue, Delevoye et al. (2009. J. Cell Biol. doi:10.1083/jcb.200907122) show that a close interaction between the clathrin adaptor AP-1 and a kinesin motor KIF13A is essential for delivering melanogenic enzymes from recycling endosomes to nascent melanosomes and for organelle biogenesis.Melanosomes, along with platelet-dense granules and lung type II alveolar cell lamellar bodies, are lysosome-related organelles (LROs), compartments that originate from endosomes but are distinct from and usually coexist with lysosomes (Fig. 1). The most characteristic features of melanosomes are their ability to synthesize and store melanin and their presence in specialized pigmented cells such as skin melanocytes and iris and retinal pigment epithelial cells (Raposo and Marks, 2007; Wasmeier et al., 2008). In this issue, Delevoye et al. (see p. 247) report a melanogenic role for the clathrin adaptor AP-1 that involves interactions between the adaptor and the plus end kinesin motor KIF13A. An impressive set of data support a scenario in which the adaptor and the motor tightly interact, like in tango, to position donor recycling endosomes (REs) near nascent melanosomes at the cell periphery and to generate tubulovesicular intermediates that deliver newly synthesized pigmenting enzymes to melanosomes.Open in a separate windowFigure 1.Role of clathrin adaptor proteins in melanosome biogenesis. Post-Golgi trafficking routes of three melanosome cargoes (Pmel17, tyrosinase, and Tyrp1) in melanocytes are shown. Newly synthesized Pmel17 is transported to the limiting membrane and intraluminal vesicles of stage I melanosomes/early sorting endosomes via the plasma membrane. This process (depicted by a question mark) might involve clathrin and AP-2. From these EEA1-positive vacuolar endosomes, Pmel17 is sorted away from the late endosome/multivesicular body pathway into stage II melanosomes. Little is known as to how the enzymes essential for melanin synthesis, tyrosinase and Tyrp1, are sorted from the TGN to early REs, and it is likely that clathrin and its adaptors are involved in this process. Tyrosinase, which binds both AP-1 and -3, is transported to stage III melanosomes from tubular regions of REs, containing Tf/TfR and Rab11, by two distinct routes: one regulated by AP-3 and the other regulated by BLOC-1, BLOC-2, and perhaps AP-1. However, Tyrp1 binds only AP-1 and not AP-3, indicating a divergence of sorting mechanisms between tyrosinase and Tyrp1. Delevoye et al. (2009) now show that AP-1 interacts with the kinesin motor KIF13A to transport recycling endosomal domains to the melanocytic cell periphery. The close apposition of Tyrp1-containing tubules with melanosomes allows cargo transfer and biogenesis of stage III and IV melanosomes. Although Tf is found in these peripheral endosomal tubules, there appears to be a filtering mechanism that sorts it out before the tubules fuse with melanosomes. It is likely, although not yet confirmed, that BLOC-1 and -2 act in concert with AP-1 to transport Tyrp1. The tissue-specific Rabs, Rab32 and Rab38, might function in any or all of these pathways.Extensive studies have shown that melanosome biogenesis occurs in two waves that correspond to four morphologically distinct stages (Fig. 1; Marks and Seabra, 2001; Raposo and Marks, 2007). The first wave (stages I and II) is the formation of immature, pigment-free ellipsoidal melanosomes from vacuolar domains of early sorting endosomes. This process requires Pmel17, an integral membrane protein that likely reaches sorting endosomes by clathrin-dependent endocytosis from the plasma membrane. Upon proteolysis in the sorting endosomes/stage I melanosomes, Pmel17 forms intraluminal proteinaceous fibrils with characteristics of amyloid. The second wave starts with the post-Golgi transport of enzymes involved in melanin synthesis such as tyrosinase and tyrosinase-related protein 1 (Tyrp1) to nascent melanosomes. Melanin deposition occurs on Pmel17 fibrils and leads to the biogenesis of mature (stages III and IV) melanosomes. The clathrin adaptors AP-1 and -3 have partially redundant functions in sorting cargo proteins to melanosomes. Melanosomal cargo proteins have dileucine motifs that are recognized differentially by AP-1 and -3 in post-Golgi endosomes (Huizing et al., 2001; Theos et al., 2005). Nascent tyrosinase is found in distinct endosomal buds that contain either AP-3 or -1 in normal melanocytes and loss of AP-3 results only in a partial mislocalization of the enzyme. As these adaptors also mediate sorting from endosomes to other compartments, additional machinery, such as biogenesis of LRO complex 1 (BLOC-1), BLOC-2, and the tissue-specific small GTPases Rab32 and Rab38, regulate cargo delivery to melanosomes. Mutations in components of this melanosomal targeting machinery result in a variety of well-studied pigmentation defects in humans and animals such as Hermansky–Pudlak syndrome (Wei, 2006).Delevoye et al. (2009) show that knockdown of AP-1 in melanocytic MNT-1 cells decreases melanin content, demonstrating that AP-1 has a role in melanogenesis. Only late-stage (III/IV) melanosomes are decreased in number; unpigmented (stage I/II) melanosomes are unaffected, indicating that AP-1 functions selectively in the second wave of melanosome biogenesis. In AP-1–depleted cells, the melanosome cargo protein Tyrp1 is retained in vacuolar endosomes in a manner similar to that seen in BLOC-1–deficient melanocytes (Setty et al., 2007). Using immunofluorescence to monitor markers of various endosomal compartments, Delevoye et al. (2009) show that AP-1 performs its melanogenic function in early REs. Interestingly, additional data show that AP-1–containing REs have a peripheral distribution in MNT-1 cells, which is strikingly different from the perinuclear localization observed in other cells. Furthermore, siRNA-mediated knockdown of AP-1, but not of AP-3, relocates RE to a pericentriolar location.How might AP-1 influence endosome position? One possibility is by its association with the plus end–directed kinesin motor KIF13A (Fig. 1). Nakagawa et al. (2000) have previously shown that a subunit of AP-1 binds the C-terminal domain of KIF13A, mediating TGN to plasma membrane transport of the mannose 6-phosphate receptor. Indeed, Delevoye et al. (2009) show that KIF13A partially colocalizes with AP-1 in MNT-1 cells and coimmunoprecipitates with both AP-1 and Tyrp1. Furthermore, knockdown of KIF13A replicates the phenotype seen with AP-1 depletion: pericentriolar clustering of RE, accumulation of Tyrp1 in vacuolar endosomes, and reduction in mature melanosomes and melanin content. Delevoye et al. (2009) go on to show that the peripheral RE localization facilitates sorting of melanosomal proteins but decreases the efficiency of transferrin (Tf) receptor (TfR) recycling to the plasma membrane. They also show the converse; i.e., the pericentriolar localization of RE decreases the efficiency of melanosomal targeting and increases the efficiency of TfR recycling. Thus, the position of REs, determined by the interaction between a clathrin adaptor and a kinesin, is key for specific sorting functions of this organelle (like TfR recycling) and also regulates the biogenesis of another organelle (the melanosome). This is a novel and exciting finding and is an emerging theme in cell biology. It was recently reported that AP-1 interacts with another plus end–directed kinesin, KIF5, which helps transport endosomes to the cell periphery (Schmidt et al., 2009).The next question that Delevoye et al. (2009) approach is what is the nature of the carriers that transport melanosomal proteins from peripheral REs to immediately adjacent stage III/IV melanosomes? Live imaging experiments showed a dynamic network of Tf-containing RE tubules that extend and retract, making contact with melanosomes for at least 30 s. Double-tilt 3D electron tomography of thick (350–400 nm) sections of cells preserved by high pressure freezing and freeze substitution, a technique recently adapted to the study of melanosomes by Hurbain et al. (2008), revealed that some of these tubular elements are continuous with the melanosomal limiting membrane and that their lumens are often connected. Collectively, these results indicate that peripheral RE domains serve to deliver biosynthetic cargo to maturing melanosomes by the coordinated actions of AP-1 and KIF13A and that the mechanism involves tubular connections rather than vesicular transport (Fig. 1).The study by Delevoye et al. (2009) beautifully demonstrates the power of carefully chosen morphological and live imaging techniques, in combination with siRNA-mediated knockdown of molecules under study, to elucidate important details of cellular sorting processes. As always, several questions emerge from their results. Does this type of mechanism also operate in perinuclear REs, which were recently shown to cooperate with adjacent TGN in biosynthetic trafficking to the plasma membrane (Cancino et al., 2007; Gravotta et al., 2007)? Do newly synthesized melanosomal enzymes move from the TGN to REs using vesicular trafficking and clathrin adaptors or, rather, result from “maturation” of REs from the TGN? What is the role of clathrin in melanosome maturation? Are AP-1 and KIF13A essential for tubulogenesis from REs as the authors speculate? How are RE proteins (e.g., TfR) prevented from incorporating into melanosomes through the tubular connections? What is the mechanism that regulates docking and fusion of RE tubules with melanosomes? Likely, Rab32 and Rab38 participate in this process, as these proteins localize to tubulovesicular endosomal structures, and their loss causes mislocalization of tyrosinase and Tyrp1 (Wasmeier et al., 2006), but the SNAREs (if any) that participate in the mechanism are still unknown. Lastly, another intriguing aspect of this study is how adaptors sort proteins by differential recognition of dileucine motifs. Tyrp1 also has a dileucine motif that exclusively binds AP-1, but not AP-3, in melanocytic cells (Theos et al., 2005), whereas tyrosinase has dileucine motifs that bind AP-1 and -3, indicating that not all dileucine motifs are equal in the eyes of the adaptor.     

Letters to the Editor

Abstract

Research has focused on identifying and overcoming determinants that impede widespread adoption of instructional interventions, with little empirical examination of postsecondary educators’ perceptions about these interventions. We explored postsecondary biology educators’ sensemaking of education improvement interventions targeting undergraduate level teaching practices at three research universities in North America. We report that educators’ sensemaking regarding interventions is situated at the intersection of their felt problems of practice and professional competencies, or what collectively might be labeled postsecondary biology educators’ focal practices, that we explore in turn. These include findings not previously identified in the literature of the choices faculty make concerning interventions they select to engage with and practice revisions they engage in. Towards encouraging more educators perceiving interventions as affordances for teaching improvement, we propose that designers of future education improvement interventions keep in mind the interplay of such perceived contextual and competency-based affordances when designing intervention features.     

From the trap to the basket: getting to the bottom of the nuclear pore complex

Nuclear pore complexes (NPCs) are large supramolecular assemblies that perforate the double-membraned nuclear envelope and serve as the sole gateways of molecular exchange between the cytoplasm and the nucleus in interphase cells. Combining novel specimen preparation regimes with innovative use of high-resolution scanning electron microscopy, Hans Ris produced in the late eighties stereo images of the NPC with unparalleled clarity and structural detail, thereby setting new standards in the field. Since that time, efforts undertaken to resolve the molecular structure and architecture, and the numerous interactions that occur between NPC proteins (nucleoporins), soluble transport receptors, and the small GTPase Ran, have led to a deeper understanding of the functional role of NPCs in nucleocytoplasmic transport. In spite of these breakthroughs, getting to the bottom of the actual cargo translocation mechanism through the NPC remains elusive and controversial. Here, we review recent insights into NPC function by correlating structural findings with biochemical data. By introducing new experimental and computational results, we reexamine how NPCs can discriminate between receptor-mediated and passive cargo to promote vectorial translocation in a highly regulated manner. Moreover, we comment on the importance and potential benefits of identifying and experimenting with individual key components implicated in the translocation mechanism. We conclude by dwelling on questions that we feel are pertinent to a more rational understanding of the physical aspects governing NPC mechanics. Last but not least, we substantiate these uncertainties by boldly suggesting a new direction in NPC research as a means to verify such novel concepts, for example, a de novo designed ‘minimalist’ NPC. This article is dedicated to the memory of Hans Ris.     

Relation of the mental foramen to teeth on the mandibles belonging to the Byzantium period

Fifty mandibles belonging to the Byzantium period were studied in order to determine to racial differences about of the localization of the mental foramen according to the mandibular teeth. Mandibles of adult males without missing teeth, proximal decay and proximal attrition were used. On the right side, the most common position of the mental foramen was between the first and second lower teeth (50%), whereas on the left side, the most common position was in line with the longitudinal axis of the lower second premolar tooth (46%). Because of materials including mostly Alpine's and a few of Mediterranean subraces, two different positions of the mental foramen were determined in high similar ratios.     

Letters to the editor

The fine structure of the colonial volvocacean alga Eudorina illinoiensis (Kofoid) Pascher is described in detail, excepting the eye spot. The structure conforms closely to the Chlamydomonas type and helps confirm that certain ultrastructural features are peculiar to certain taxonomic groups, the characteristic structure of the transitional region of the flagellum being an example in this case. A spiral filament around the outer doublets of the axoneme is newly reported.

Particular attention is given to the flagellar apparatus and to the structure of the chloroplast in relation to the pyrenoid. Small stacks of thylakoids pass between the starch plates to enter the pyrenoid where they assume a tubular form. The spatial re-organisations required to achieve this are described.     

Human calumenin localizes to the secretory pathway and is secreted to the medium

Calumenin belongs to a family of multiple EF-hand proteins that include reticulocalbin, ERC-55, and Cab45. Reticulocalbin and ERC-55 localize to the ER due to a C-terminal HDEL retrieval signal. Cab45 contains a HEEF C-terminal sequence and is localized to the Golgi apparatus. The murine homologue of calumenin is reported to be present in the ER due to a C-terminal HDEF retrieval signal. The human homologue differs from the murine at 7 amino acid positions but the HDEF signal is conserved. However, in the cultured human cell lines, HaCaT keratinocytes, normal and transformed MRC-5 fibroblasts, as well as in transfected COS-1 cells, human calumenin could be demonstrated in the ER as well as in the Golgi complex. Especially in MRC-5 cells, a certain heterogeneity was observed, with some of the cells having calumenin localized solely to the ER while in other cells calumenin could be demonstrated in the ER as well as in the Golgi complex. Immunoelectron microscopy of placental syncytiotrophoblast cells showed that a substantial fraction of calumenin is localized in close association with the ER membrane. In addition, the protein may be recovered from the medium of cultured cells in an endoglycosidase H-resistant form, suggesting that the glycosylated protein has been further modified in the Golgi apparatus and secreted to the medium.     

Journey to the skin

The peripheral axons of vertebrate tactile somatosensory neurons travel long distances from ganglia just outside the central nervous system to the skin. Once in the skin these axons form elaborate terminals whose organization must be regionally patterned to detect and accurately localize different kinds of touch stimuli. This review describes key studies that identified choice points for somatosensory axon growth cones and the extrinsic molecular cues that function at each of those steps. While much has been learned in the past 20 years about the guidance of these axons, there is still much to be learned about how the peripheral axons of different kinds of somatosensory neurons adopt different trajectories and form specific terminal structures.     

Key to the management of the Western Himalayan Hillstreams in relation to

A key to the management of hillstreams in relation to Fish Species Richness (FSR) and Shannon and Weaver Diversity Index (H) (Shannon and Weaver, 1949. The Mathematical Theory of Communications. Urbana, University of Illinois Press, IL, USA) using a multitude of factors such as altitude, water source, bed gradient, dominant channel materials and habitat type has been proposed on the basis of 10 study sites, belonging to three north Indian rivers namely; Ghaggar, Yamuna and Ganga. The selected streams are located between the altitudes ranging from 380 to 1524m. It has been observed that high altitude streams having steep gradient, boulder dominated substrate with rapids as the main habitat type had lower FSR (3–4) and H (0.55–0.99) as compared to hillstreams located in the lower altitudes having gentle gradient, cobble dominated substrate with pools, riffles, runs, rapids and cascades as the main habitats and have high FSR (6–14) and H (1.67–2.35). Types – A, B and F hillstreams were encountered when the hillstreams are classified after Rosgen (Applied River Morphology, Wildland Hydrology, Co, USA).     

Letters to the Editor

The following is the abstract of the article discussed inthe subsequent letter:

Yuan, Huichin, Edward P. Ingenito, and BélaSuki. Dynamic properties of lung parenchyma: mechanicalcontributions of fiber network and interstitial cells. J. Appl.Physiol. 83(5): 1420-1431, 1997.We investigated thecontributions of the connective tissue fiber network and interstitialcells to parenchymal mechanics in a surfactant-free system. In eightstrips of uniform dimension from guinea pig lung, we assessed thestorage (G') and loss (G") moduli by using pseudo-random lengthoscillations containing a specially designed set of seven frequenciesfrom 0.07 to 2.4 Hz at baseline, during methacholine (MCh) challenge,and after death of the interstitial cells. Measurements were made atmean forces of 0.5 and 1 g and strain amplitudes of 5, 10, and 15% andwere repeated 12 h later in the same, but nonviable samples. Theresults were interpreted using a linear viscoelastic modelincorporating both tissue damping (G) and stiffness (H). The G' and G"increased linearly with the logarithm of frequency, and both G and Hshowed negative strain amplitude and positive mean force dependence. After MCh challenge, the G' and G" spectra were elevated uniformly, andG and H increased by <15%. Tissue stiffness, strain amplitude, andmean force dependence were virtually identical in the viable andnonviable samples. The G and hence energy dissipation were ~10%smaller in the nonviable samples due to absence of actin-myosin cross-bridge cycling. We conclude that the connective tissue network may also dominate parenchymal mechanics in the intact lung, which canbe influenced by the tone or contraction of interstitial cells.

     

On the possibilities to apply the result from an LCA disclosed to public

Aim, Scope and background  Given the communication limitation of a damage-oriented approach, the question addressed in this paper is how normalisation can be developed instead. Normalisation of product service systems without value choices is, in accordance to ISO 14042, suitable for external communication. Reason normalisation approaches use a geographically-defined baseline year of emissions, optionally combined with politically established target emissions (Guinée 2002, Stranddorf et al. 2001). In contradiction to these approaches, this paper aims to draw up the general structure of an alternative normalisation procedure. The normalisation procedure suggested here is based on environmental quality objectives (EQO), in order to streamline the result to include as few output parameters as possible, without compromising the scientific robustness of the method. Main Features  This article describes a normalisation procedure based on environmental quality objectives. Comparison between this approach and a damage-oriented approach is conducted. The relevant working area concerning dose and effect is evaluated. Then a discussion is conducted focusing on the trade-off necessary to achieve an integrated category indicator, covering the following issues; model reliability, user applicability and the unambiguously of the result. Result  A damage-oriented approach will have to take into account all the defined consequences from all impact categories that affect the safeguards in parallel. In other words, each impact category indicator and its potential effects on all safeguards must be evaluated and accounted for. In the case where a single category indicator cannot be found without utilising value choices, a number of category indicators will then have to constitute an intermediate category indicator result, where weighting must be applied in order to streamline the result. In contrast to the above approach, the suggested normalisation procedure utilises the precautionary principle with respect to the essential EQO in order to achieve a category indicator result, called a critical load category indicator result. In practice, this means that the number of figures in an LCIA-profile based on critical load will always be the same as the number of impact categories. Conclusions  The suggested EQO normalisation procedure forms a set of critical loads per impact category, where each is defined by a critical load function where linearity is defined between a zero load and the critical load. This procedure will affect the temporal resolution and the field of application of the LCIA method. The positive aspect is that the suggested normalisation procedure renders the method applicable for long-lived products like, for example, buildings or other infrastructures. This aspect is gained by reducing the damage-oriented resolution. Consequently, for long-lived products where the main environmental loads will appear in the future, it is hard to assess by a damage-oriented LCIA method (if all boundary conditions are not assumed to be fixed). The EQO normalisation method will, in this respect, improve the overall reliability of the outcome of an LCA when long-lived products are assessed. For short-lived products, adequate boundary conditions can be achieved, and for this reason a damage-oriented approach will have the possibility to address current consequences. Nevertheless, a damage-oriented approach working area is not applicable beneath thresholds unlike the EQO normalisation procedure. The most effective decision support of short-lived products is therefore achieved when both approaches are applied. Outlook  A complementary paper will be produced where the described normalisation procedure is exemplified in a case study, with special interest on assessment of chemical substances.     

Letters to the Editor

Abstract

Hot commercial dishwashing detergent has been used to deparaffinize and hydrate formalin fixed, paraffin embedded sections for immunohistochemistry. Fifty-five antibodies, used routinely for diagnosis, were used to compare hot detergent dewaxing with the proprietary hydrocarbon-based dewaxing reagent supplied with the Bond Max immunohistochemistry system^®. A 2% concentration of commercial dishwashing detergent in distilled water was heated to 90° C and paraffin sections were treated twice for 1 min each. Nearly all antibodies gave equivalent results except CD10 and CD57 (hydrocarbon-based dewaxing better) and CD45 and alpha fetoprotein (detergent dewaxing better); the differences, however, were minimal. There also was a significant cost saving using detergent dewaxing.