Analysis of the different techniques to include noise damage in life cycle assessment. A case study for car tires

Purpose

Despite that different methods for the inclusion of transport noise in life cycle assessment (LCA) have been proposed, none of them has become consensual. Leveraging a case study on car tires, this paper aims at comparing two among these characterization approaches to identify strengths and weaknesses and to investigate the relative contribution of noise to human health (in disability-adjusted life years (DALYs)) as compared to other environmental stressors.

Methods

The case study analyzed two tires showing different acoustical properties. The two methods applied are the one developed by Müller-Wenk and further improved by other authors and the recent one proposed by Cucurachi. These two methods were adapted to the case study, and a full LCA study of the car tires was carried out. Both uncertainty and sensitivity analyses were performed.

Results and discussion

Both methods highlight the potential high contribution of noise damage to the DALYs generated by car tires, even considering parameters’ uncertainties. This study shows therefore the necessity to integrate noise impact in LCA in a broader way. Both methods present coherent results regarding the environmental performance differences between the two products. However, the absolute DALY scores differ by eight orders of magnitude, probably because Cucurachi’s methods overestimate the damages. The analysis of modeling choices and parameter uncertainties could not explain this difference.

Conclusions

Noise impact on human health has to be included in LCA, and additional efforts should focus on the characterization modeling since there is not yet a consensual method for a systematic integration. The case study shows that the improvement of tire design can efficiently reduce noise impact on human health. Both methods have advantages and inconveniences. We think that it is possible to elaborate a method combining the strengths of both approaches. An incremental approach used on accurate localized and temporalized data processed with noise propagation software could provide characterization factors for a set of archetypes. This should be a good compromise for a method allowing systematic integration of noise impact in LCA.

     

AnovArray: a set of SAS macros for the analysis of variance of gene expression data

Background  

Analysis of variance is a powerful approach to identify differentially expressed genes in a complex experimental design for microarray and macroarray data. The advantage of the anova model is the possibility to evaluate multiple sources of variation in an experiment.     

Genomic features of lactic acid bacteria effecting bioprocessing and health

The lactic acid bacteria are a functionally related group of organisms known primarily for their bioprocessing roles in food and beverages. More recently, selected members of the lactic acid bacteria have been implicated in a number of probiotic roles that impact general health and well-being. Genomic analyses of multiple members of the lactic acid bacteria, at the genus, species, and strain level, have now elucidated many genetic features that direct their fermentative and probiotic roles. This information is providing an important platform for understanding core mechanisms that control and regulate bacterial growth, survival, signaling, and fermentative processes and, in some cases, potentially underlying probiotic activities within complex microbial and host ecosystems.     

Lactobacillus bulgaricus Proteinase Expressed in Lactococcus lactis Is a Powerful Carrier for Cell Wall-Associated and Secreted Bovine β-Lactoglobulin Fusion Proteins

Lactic acid bacteria have a good potential as agents for the delivery of heterologous proteins to the gastrointestinal mucosa and thus for the reequilibration of inappropriate immune responses to food antigens. Bovine β-lactoglobulin (BLG) is considered a major allergen in cow's milk allergy. We have designed recombinant Lactococcus lactis expressing either full-length BLG or BLG-derived octapeptide T6 (IDALNENK) as fusions with Lactobacillus bulgaricus extracellular proteinase (PrtB). In addition to constructs encoding full-length PrtB for the targeting of heterologous proteins to the cell surface, we generated vectors aiming at the release into the medium of truncated PrtB derivatives lacking 100 (PrtB, PrtB-BLG, and PrtB-T6) or 807 (PrtBΔ) C-terminal amino acids. Expression of recombinant products was confirmed using either anti-PrtB, anti-BLG, or anti-peptide T6 antiserum. All forms of the full-length and truncated recombinant products were efficiently translocated, irrespective of the presence of eucaryotic BLG sequences in the fusion proteins. L. lactis expressing PrtB-BLG yielded up to 170 μg per 10⁹ CFU in the culture supernatant and 9 μg per 10⁹ CFU at the bacterial cell surface within 14 h. Therefore, protein fusions relying on the use of PrtB gene products are adequate for concomitant cell surface display and secretion by recombinant L. lactis and thus may ensure maximal bioavailability of the eucaryotic antigen in the gut-associated lymphoid tissue.     

Avian HSC emergence, migration, and commitment toward the T cell lineage

To date three sites of emergence of hemopoietin cells have been identified during early avian development: the yolk sac, the intraaortic clusters and recently the allantois. However, the contributions of the hematopoietic stem cell (HSC) populations generated by these different sites to definitive hematopoiesis and their migration routes are not fully unraveled. Experimental embryology as well as the establishment of the genetic cascades involved in HSC emergence help now to draw a better scheme of these processes.     

Regulated cell surface pro-EGF ectodomain shedding is a zinc metalloprotease-dependent process

Epidermal growth factor receptor (EGFR) ligands are synthesized as type I membrane protein precursors exposed at the cell surface. Shedding of the ectodomain of these proteins is the way cells regulate the equilibrium between cell-associated and diffusible forms of these growth factors. Whereas the regulated shedding of transforming growth factor-alpha, HB-EGF, and amphiregulin precursors have been clearly established, regulation of full-length pro-EGF shedding has not been clearly demonstrated. Here, using both wild-type and M2 mutant CHO-K1 as well as HeLa cell lines transiently transfected with epitope-tagged rat pro-EGF expression plasmid, we demonstrate that these cells synthesize EGF as a high molecular weight membrane-associated precursor glycoprotein expressed at the cell surface. All cell lines are able to release the entire ectodomain of pro-EGF in the extracellular medium following juxtamembrane cleavage of the precursor once it is present at the cell surface. More significantly we clearly established that CHO-M2 and HeLa cells only constitutively release low levels of pro-EGF. This shedding is a regulated phenomenon in wild-type CHO cells where it can be induced by different agents such as phorbol 12-myristate 13-acetate (PMA), pervanadate, and serum but not by calcium ionophores. Using specific inhibitors as well as protein kinase C (PKC) depletion, PMA stimulation was shown to be completely dependent on PKC activation whereas pervanadate and serum stimulation were not. Regulated ectodomain shedding involves the activity of a zinc metalloprotease as determined by inhibition with phenantrolin and TAPI-2 and by the results obtained with the CHO-M2 shedding defective mutant cell line. Comparison of the ability of CHO and HeLa cell lines to shed pro-EGF and pro-TNF-alpha upon stimulation greatly suggests that TACE (ADAM 17) may not be the ectoprotease involved in the secretion of pro-EGF ectodomain and that this protease, which remains to be identified, shows a restricted cellular expression pattern.     

Characterization of a gene encoding two isoforms of a mitochondrial protein up-regulated by cyclosporin A in activated T cells

Cyclosporin A (CSA) is an immunosuppressor used in organ transplantation. A recent proteomic analysis has revealed that activation of T cells in the presence of CSA induces the synthesis of hundreds of new proteins. Here we used representational difference analysis to characterize some of the corresponding induced genes. After cDNA bank screening we focused on one of these genes, which we named CSA-conditional, T cell activation-dependent (CSTAD) gene. This gene produces two mRNAs resulting from alternative splicing events. They encode two proteins of 104 and 141 amino acids, CSTADp-S and CSTADp-L, for the short and long forms, respectively. FK506 had the same effect as CSA, whereas rapamycin did not affect the level of CSTAD gene expression, demonstrating that inhibition of the calcineurin activation pathway is involved in CSTAD gene up-regulation. CSA also led to overexpression of CSTAD in mice immunized in the presence of CSA, confirming the in vitro analysis. Microscopic and cytofluorimetric analysis of cells expressing green fluorescent protein-tagged CSTADp-L and CSTADp-S showed that both proteins colocalize with mitochondrial markers and depolarize the mitochondrial transmembrane potential without causing release of cytochrome c, apoptosis, or necrosis. Both CSTADp isoforms are sensitive to proteinase K, implying that they are located in the mitochondrial outer membrane. These data reveal a new mechanism of action for CSA, which involves up-regulation of a gene whose products are sorted to mitochondria and depolarize the mitochondrial membrane.     

Mouse bestrophin-2 is a bona fide Cl(-) channel: identification of a residue important in anion binding and conduction

Bestrophins have recently been proposed to comprise a new family of Cl(-) channels. Our goal was to test whether mouse bestrophin-2 (mBest2) is a bona fide Cl(-) channel. We expressed mBest2 in three different mammalian cell lines. mBest2 was trafficked to the plasma membrane as shown by biotinylation and immunoprecipitation, and induced a Ca(2+)-activated Cl(-) current in all three cell lines (EC(50) for Ca(2+) = 230 nM). The permeability sequence was SCN(-): I(-): Br(-): Cl(-): F(-) (8.2: 1.9: 1.4: 1: 0.5). Although SCN(-) was highly permeant, its conductance was approximately 10% that of Cl(-) and SCN(-) blocked Cl(-) conductance (IC(50) = 12 mM). Therefore, SCN(-) entered the pore more easily than Cl(-), but bound more tightly than Cl(-). Mutations in S79 altered the relative permeability and conductance for SCN(-) as expected if S79 contributed to an anion binding site in the channel. P(SCN)/P(Cl) = 8.2 +/- 1.3 for wild-type and 3.9 +/- 0.4 for S79C. G(SCN)/G(Cl) = 0.14 +/- 0.03 for wild-type and 0.94 +/- 0.04 for S79C. In the S79 mutants, SCN(-) did not block Cl(-) conductance. This suggested that the S79C mutation altered the affinity of an anion binding site for SCN(-). Additional evidence that S79 was located in the conduction pathway was provided by the finding that modification of the sulfhydryl group in S79C with MTSET(+) or MTSES(-) increased conductance significantly. Because the effect of positively and negatively charged MTS reagents was similar, electrostatic interactions between the permeant anion and the channel at this residue were probably not critical in anion selectivity. These data provide strong evidence that mBest2 forms part of the novel Cl(-) conduction pathway in mBest2-transfected cells and that S79 plays an important role in anion binding in the pore of the channel.     

Intracellular calcium handling heterogeneities in intact guinea pig hearts

Regional heterogeneities of ventricular repolarizing currents and their role in arrhythmogenesis have received much attention; however, relatively little is known regarding heterogeneities of intracellular calcium handling. Because repolarization properties and contractile function are heterogeneous from base to apex of the intact heart, we hypothesize that calcium handling is also heterogeneous from base to apex. To test this hypothesis, we developed a novel ratiometric optical mapping system capable of measuring calcium fluorescence of indo-1 at two separate wavelengths from 256 sites simultaneously. With the use of intact Langendorff-perfused guinea pig hearts, ratiometric calcium transients were recorded under normal conditions and during administration of known inotropic agents. Ratiometric calcium transients were insensitive to changes in excitation light intensity and fluorescence over time. Under control conditions, calcium transient amplitude near the apex was significantly larger (60%, P < 0.01) compared with the base. In contrast, calcium transient duration was significantly longer (7.5%, P < 0.03) near the base compared with the apex. During isoproterenol (0.05 microM) and verapamil (2.5 microM) administration, ratiometric calcium transients accurately reflected changes in contractile function, and, the direction of base-to-apex heterogeneities remained unchanged compared with control. Ratiometric optical mapping techniques can be used to accurately quantify heterogeneities of calcium handling in the intact heart. Significant heterogeneities of calcium release and sequestration exist from base to apex of the intact heart. These heterogeneities are consistent with base-to-apex heterogeneities of contraction observed in the intact heart and may play a role in arrhythmogenesis under abnormal conditions.