bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bridging the gap between ‘planning’ and ‘doing’ for biodiversity conservation in freshwaters
Authors: BARMUTA LEON A. , LINKE SIMON , TURAK EREN 
Published: October 2010

Summary1. Systematic conservation planning has been applied to terrestrial and marine systems for over a decade, but only recently been used for freshwaters. Of the various methods proposed, those that explicitly include the costs of, opportunities for and constraints on conservation actions are the most defensible because they allow transparent, rational decisions to be made about conservation priorities.2. Applying these procedures to freshwater systems presents a number of challenges, including accounting for lateral, longitudinal and vertical connections, and the dynamism and resilience of freshwaters in space and time. Recent research on freshwater conservation planning contains an array of methods to address these issues.3. The first step in bridging the implementation gap will be to communicate that conserving aquatic biodiversity often will not be achieved by merely ‘locking up’ catchments and that many human uses can coexist with biodiversity conservation.4. To bridge the gap between research and implementation, terrestrial experience suggests that genuinely collaborative involvement with stakeholders and managers needs to be part of the planning process. Otherwise, even the most transparently optimised conservation plan will be ignored.5. Case studies explored by the advocates of social learning and ‘resilience thinking’ provide frameworks for creative engagement between the ecological and social sciences. There is probably scope to modify existing catchment management networks to incorporate aquatic biodiversity conservation.
Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE‐1 is mediated by the global regulator, FixK
Authors: Bose Arpita , Newman Dianne K. 
Published: October 2010

SummaryThe pioABC operon is required for phototrophic iron oxidative (photoferrotrophic) growth by the α‐proteobacterium Rhodopseudomonas palustris TIE‐1. Expression analysis of this operon showed that it was transcribed and translated during anaerobic growth, upregulation being observed only under photoferrotrophic conditions. Very low levels of transcription were observed during aerobic growth, suggesting expression was induced by anoxia. The presence of two canonical FixK boxes upstream of the identified pioABC transcription start site implicated FixK as a likely regulator. To test this possibility, a ΔfixK mutant of R. palustris TIE‐1 was assessed for pioABC expression. pioABC expression decreased dramatically in ΔfixK versus WT during photoferrotrophic growth, implying that FixK positively regulates its expression; coincidently, the onset of iron oxidation was prolonged in this mutant. In contrast, pioABC expression increased in ΔfixK under all non‐photoferrotrophic conditions tested, suggesting the presence of additional levels of regulation. Purified FixK directly bound only the proximal FixK box in gel mobility‐shift assays. Mutant expression analysis revealed that FixK regulates anaerobic phototrophic expression of other target genes with FixK binding sites in their promoters. This study shows that FixK regulates key iron metabolism genes in an α‐proteobacterium, pointing to a departure from the canonical Fur/Irr mode of regulation.
Functional and structural characterization of a novel mannosyl‐3‐phosphoglycerate synthase from Rubrobacter xylanophilus reveals its dual substrate specificity
Authors: Empadinhas Nuno , Pereira Pedro José Barbosa , Albuquerque Luciana , Costa Joana , Sá‐Moura Bebiana , Marques Alexandra T. , Macedo‐Ribeiro Sandra , da Costa Milton S. 
Published: October 2010

Summary Rubrobacter xylanophilus is the only actinobacterium known to accumulate the organic solute mannosylglycerate (MG); moreover, the accumulation of MG is constitutive. The key enzyme for MG synthesis, catalysing the conversion of GDP‐mannose (GDP‐Man) and D‐3‐phosphoglycerate (3‐PGA) into the phosphorylated intermediate mannosyl‐3‐phosphoglycerate and GDP, was purified from R. xylanophilus cell extracts and the corresponding gene was expressed in E. coli. Despite the related solute glucosylglycerate (GG) having never been detected in R. xylanophilus, the cell extracts and the pure recombinant mannosyl‐3‐phosphoglycerate synthase (MpgS) could also synthesize glucosyl‐3‐phosphoglycerate (GPG), the precursor of GG, in agreement with the higher homology of the novel MpgS towards GPG‐synthesizing mycobacterial glucosyl‐3‐phosphoglycerate synthases (GpgS) than towards MpgSs from hyper/thermophiles, known to accumulate MG under salt or thermal stress. To understand the specificity and substrate ambiguity of this novel enzyme, we determined the crystal structure of the unliganded MpgS and of its complexes with the nucleotide and sugar donors, at 2.2, 2.8 and 2.5 Å resolution respectively. The first three‐dimensional structures of a protein from this extremely gamma‐radiation‐resistant thermophile here reported show that MpgS (GT81 family) contains a GT‐A like fold and clearly explain its nucleotide and sugar‐donor specificity. In the GDP–Man complex, a flexible loop (254RQNRHQ259), located close to the active site moves towards the incoming sugar moiety, providing the ligands for both magnesium ion co‐ordination and sugar binding. A triple mutant of R. xylanophilus MpgS, mimicking the 206PLAGE210 loop stabilizing hydrogen bond network observed for mycobacterial GpgSs, reduces significantly the affinity to GDP–Man, implicating this loop in the sugar‐donor discrimination.
YeeV is an Escherichia coli toxin that inhibits cell division by targeting the cytoskeleton proteins, FtsZ and MreB
Authors: Tan Qian , Awano Naoki , Inouye Masayori 
Published: October 2010

SummaryToxin–antitoxin (TA) systems of free‐living bacteria have recently demonstrated that these toxins inhibit cell growth by targeting essential functions of cellular metabolism. Here we show that YeeV toxin inhibits cell division, leads to a change in morphology and lysis of Escherichia coli cells. YeeV interacts with two essential cytoskeleton proteins, FtsZ and MreB. Purified YeeV inhibits both the GTPase activity and the GTP‐dependent polymerization of FtsZ. YeeV also inhibits ATP‐dependent polymerization of MreB. Truncated C‐terminal deletions of YeeV result in elongation of cells, and a deletion of the first 15 amino acids from the N‐terminus of YeeV caused lemon‐shaped cell formation. The YeeV toxin is distinct from other well‐studied toxins: it directs the binding of two cytoskeletal proteins and inhibits FtsZ and MreB simultaneously.
A domino effect in drug action: from metabolic assault towards parasite differentiation
Authors: Haanstra Jurgen R. , Kerkhoven Eduard J. , van Tuijl Arjen , Blits Marjolein , Wurst Martin , van Nuland Rick , Albert Marie‐Astrid , Michels Paul A. M. , Bouwman Jildau , Clayton Christine , Westerhoff Hans V. , Bakker Barbara M. 
Published: October 2010

SummaryAwareness is growing that drug target validation should involve systems analysis of cellular networks. There is less appreciation, though, that the composition of networks may change in response to drugs. If the response is homeostatic (e.g. through upregulation of the target protein), this may neutralize the inhibitory effect. In this scenario the effect on cell growth and survival would be less than anticipated based on affinity of the drug for its target. Glycolysis is the sole free‐energy source for the deadly parasite Trypanosoma brucei and is therefore a possible target pathway for anti‐trypanosomal drugs. Plasma‐membrane glucose transport exerts high control over trypanosome glycolysis and hence the transporter is a promising drug target. Here we show that at high inhibitor concentrations, inhibition of trypanosome glucose transport causes cell death. Most interestingly, sublethal concentrations initiate a domino effect in which network adaptations enhance inhibition. This happens via (i) metabolic control exerted by the target protein, (ii) decreases in mRNAs encoding the target protein and other proteins in the same pathway, and (iii) partial differentiation of the cells leading to (low) expression of immunogenic insect‐stage coat proteins. We discuss how these ‘anti‐homeostatic’ responses together may facilitate killing of parasites at an acceptable drug dosage.
A molecular mechanism that stabilizes cooperative secretions in Pseudomonas aeruginosa
Authors: Xavier Joao B. , Kim Wook , Foster Kevin R. 
Published: October 2010

SummaryBacterial populations frequently act as a collective by secreting a wide range of compounds necessary for cell–cell communication, host colonization and virulence. How such behaviours avoid exploitation by spontaneous ‘cheater’ mutants that use but do not contribute to secretions remains unclear. We investigate this question using Pseudomonas aeruginosa swarming, a collective surface motility requiring massive secretions of rhamnolipid biosurfactants. We first show that swarming is immune to the evolution of rhlA‐‘cheaters’. We then demonstrate that P. aeruginosa resists cheating through metabolic prudence: wild‐type cells secrete biosurfactants only when the cost of their production and impact on individual fitness is low, therefore preventing non‐secreting strains from gaining an evolutionary advantage. Metabolic prudence works because the carbon‐rich biosurfactants are only produced when growth is limited by another growth limiting nutrient, the nitrogen source. By genetically manipulating a strain to produce the biosurfactants constitutively we show that swarming becomes cheatable: a non‐producing strain rapidly outcompetes and replaces this obligate cooperator. We argue that metabolic prudence, which may first evolve as a direct response to cheating or simply to optimize growth, can explain the maintenance of massive secretions in many bacteria. More generally, prudent regulation is a mechanism to stabilize cooperation.
Separating parental environment from seed size effects on next generation growth and development in Arabidopsis
Authors: ELWELL ANGELA L. , GRONWALL DAVID S. , MILLER NATHAN D. , SPALDING EDGAR P. , DURHAM BROOKS TESSA L. 
Published: October 2010

ABSTRACTPlant growth and development is profoundly influenced by environmental conditions that laboratory experimentation typically attempts to control. However, growth conditions are not uniform between or even within laboratories and the extent to which these differences influence plant growth and development is unknown. Experiments with wild‐type Arabidopsis thaliana were designed to quantify the influences of parental environment and seed size on growth and development in the next generation. A single lot of seed was planted in six environmental chambers and grown to maturity. The seed produced was mechanically sieved into small and large size classes then grown in a common environment and subjected to a set of assays spanning the life cycle. Analysis of variance demonstrated that seed size effects were particularly significant early in development, affecting primary root growth and gravitropism, but also flowering time. Parental environment affected progeny germination time, flowering and weight of seed the progeny produced. In some cases, the parental environment affected the magnitude of (interacted with) the observed seed size effects. These data indicate that life history circumstances of the parental generation can affect growth and development throughout the life cycle of the next generation to an extent that should be considered when performing genetic studies.
Minimum hydraulic safety leads to maximum water‐use efficiency in a forage grass
Authors: HOLLOWAY‐PHILLIPS MEISHA‐MARIKA , BRODRIBB TIMOTHY J. 
Published: October 2010

ABSTRACTUnderstanding how water‐use regulation relates to biomass accumulation is imperative for improving crop production in water‐limited environments. Here, we examine how the vulnerability of xylem to water stress‐induced cavitation and the coordination between water transport capacity and assimilation (A) influences diurnal water‐use efficiency (WUE) and dry‐matter production in Lolium perenne L. – a commercial forage grass. Plants were exposed to a range of water stresses, causing up to 90% leaf death, by withholding water and then rewatering to observe the recovery process. Leaf hydraulic conductance (Kleaf) declined to 50% of maximum at a leaf water potential (ψleaf) of −1 MPa, whereas complete stomatal closure occurred well after this point, at −2.35 MPa, providing no protection against hydraulic dysfunction. Instantaneous A remained maximal until >70% of hydraulic conductivity had been lost. Post‐stress rewatering showed that 95% loss of Kleaf could be incurred before the recovery of gas exchange exceeded 1 d, with a rapid transition to leaf death after this point. Plants exposed to sustained soil water deficits through restricted nightly watering regimes did not suffer cumulative losses in Kleaf; instead, ψleaf and gas exchange recovered diurnally. The effect was improved WUE during the day and optimal ψleaf during the night for the maintenance of growth.
Regulation of xenogeneic porcine pancreatic islets
Authors: Arcidiacono Judith A. , Evdokimov Evgenij , Lee Mark H. , Jones Jeff , Rudenko Larisa , Schneider Bruce , Snoy Phillip J. , Wei Cheng‐Hong , Wensky Allen K. , Wonnacott Keith 
Published: October 2010

Arcidiacono JA, Evdokimov E, Lee MH, Jones J, Rudenko L, Schneider B, Snoy PJ, Wei C‐H, Wensky AK, Wonnacott K. Regulation of xenogeneic porcine pancreatic islets. Xenotransplantation 2010; 17: 329–337. © 2010 John Wiley & Sons A/S.Abstract:  The use of xenogeneic porcine pancreatic islets has been shown to be a potentially promising alternative to using human allogeneic islets to treat insulin‐dependent type 1 diabetes (T1D). This article provides an overview of the existing FDA regulatory framework that would be applied to the regulation of clinical trials utilizing xenogeneic porcine pancreatic islets to treat T1D.
Transplantation of mouse embryonic stem cells induces hematopoietic and tissue chimerism in rats
Authors: Baertschiger Reto M. , Gonelle‐Gispert Carmen , Morel Philippe , Sgroi Antonino , Serre‐Beinier Veronique , Stouffs Michael , Jaconi Marisa E. , Bühler Leo H. 
Published: October 2010

Baertschiger RM, Gonelle‐Gispert C, Morel P, Sgroi A, Serre‐Beinier V, Stouffs M, Jaconi ME, Bühler LH. Transplantation of mouse embryonic stem cells induces hematopoietic and tissue chimerism in rats. Xenotransplantation 2010; 17: 362–369. © 2010 John Wiley & Sons A/S.Abstract:  Embryonic stem cells (ESC) can differentiate into all cell lineages, and ESC‐like cells were shown to induce hematopoietic chimerism and tolerance in allogeneic models. The aim of our study was to test the capacity of mouse ESC (mESC) to engraft in rats in a xenotransplantation setting. Forty‐six rats were transplanted intravenously with 1 million mESC, without immunosuppression (group 1, n = 23) or with cyclosporine (group 2, n = 23). Three months after mESC transplantation, skin grafts were performed from allogeneic, xenogeneic identical to mESC, or xenogeneic third party donors. At day 27 post‐transplant, we detected circulating mouse cells in the blood of 4/23 and 5/23 animals of group 1 and group 2, respectively. Chimerism was confirmed by PCR. We also identified long‐term surviving murine cells within livers of chimeric animals. Skin grafts showed no difference in survival between allogeneic and xenogeneic donors. Transplantation of xenogeneic mouse ESC induced short‐term chimerism in the blood and persistent tissue chimerism in the liver of recipient rats, but did not induce tolerance to skin grafts. Improved immunosuppressive protocols should be tested to prolong chimerism and allow tolerance.
Korean attitudes to Xenotransplantation: a survey conducted in 20091
Authors: Mo Hyojung , Kwon Ivo 
Published: October 2010

Mo H, Kwon I. Korean attitudes to Xenotransplantation: a survey conducted in 2009. Xenotransplantation 2010; 17: 391–395. © 2010 John Wiley & Sons A/S.Abstract: Background:  Xenotransplantation research has been being actively conducted in Korea. However, there are numbers of socio‐ethical issues involved in this research, and it is necessary to know public attitudes toward the research, inducing “public consensus” for the sound development of the technology.Materials and methods:  A telephone survey consisting of 10 questionnaire items was conducted to investigate the attitudes of Koreans on social and ethical issues related to xenotransplantation. Participants were randomly selected in proportion to the 2009 Korean population census. The response rate was 22.3%. Finally, 500 sets of data were collected and analyzed with SPSS® 12. A statistical analysis was performed using the chi‐square test.Results:  In the first phase of the study, 69.8% of the respondents were positive about xenotransplantation while 29.0% were negative. However, after being informed of the specific benefit and risk, 58.4% of the respondents stated that xenotransplantation research should be continued, while 38.6% of them indicated that these studies should be prohibited; 63.0% of the respondents agreed with lifelong surveillance after xenotransplantation, while 34.0% disagreed. To avoid triggering immune response in the transplantees, 63.0% of the respondents also approved of the necessity of genetic modification of pigs. If xenotransplantation proves to be safe, 56.8% of the respondents said that they would accept it if necessary; 69.8% of the respondents would recommend it for their family members and friends as a therapeutic option if they are in need. Men were more positive than women about the necessity of animal experimentation for xenotransplantation research, the necessity of lifelong surveillance, and the necessity of genetic modification of pigs. There was no significant difference between the religious and non‐religious group except about the issue of lifelong surveillance.Conclusion:  Korean people have relatively positive attitudes toward xenotransplantation research and animal experiments regarding xenotransplantation.
The fate of human platelets perfused through the pig liver: implications for xenotransplantation
Authors: Burlak Christopher , Paris Leela L. , Chihara Ray K. , Sidner Richard A. , Reyes Luz M. , Downey Susan M. , Tector A. Joseph 
Published: October 2010

Burlak C, Paris LL, Chihara RK, Sidner RA, Reyes LM, Downey SM, Tector AJ. The fate of human platelets perfused through the pig liver: implications for xenotransplantation. Xenotransplantation 2010; 17: 350–361. © 2010 John Wiley & Sons A/S.Abstract: Background:  Pig liver xenotransplantation could offset the shortage of livers available for orthotopic liver transplantation. Studies in pig and baboon liver xenografts revealed the main obstacle to be a lethal thrombocytopenia that occurred within minutes to hours of transplantation.Methods:  We have created a model of xenotransplantation‐induced thrombocytopenia using ex vivo pig liver perfusion with human platelets. Thrombocytopenia was examined using fluorescently labeled platelets during the ex vivo perfusion and coculture with primary liver sinusoidal endothelial cells (LSEC).Results:  Ex vivo liver perfusion revealed that 93% of human platelets were removed from circulation after 15 min. Endothelial cells and platelets were not activated based on tissue factor release into the perfusate. Biopsies from the ex vivo perfusion at 15 and 30 min and in vitro analysis indicated that human platelets are phagocytosed by pig LSEC and degraded in phagosomes. Sixty to 120 min after the addition of platelets to the ex vivo perfusion system, we observed platelet fragments and degraded platelets in hepatocytes. Platelet phagocytosis was not mediated by opsonization as Fc blocking had no effect on platelet phagocytosis. In vitro uptake of human platelets by primary LSEC cultures peaked at 15 min followed by a greater than 55% decrease in platelet fluorescence after 3 h. Primary pig LSEC phagosomes containing human platelets were colocalized with lysosomes positive for lysosome‐associated membrane protein‐1 (LAMP1), indicating the formation of mature phagosomes within pig LSEC.Conclusions:  Our observation of pig LSEC phagocytosis of human platelets describes a novel mechanism of large‐particle uptake in the liver. The creation of a model system to study xenotransplantation‐induced thrombocytopenia makes possible the investigation into mechanisms that mediate platelet loss.
Creation of a prevascularized site for cell transplantation in rats
Authors: Stiegler Philipp , Matzi Veronika , Pierer Eve , Hauser Oliver , Schaffellner Silvia , Renner Heiko , Greilberger Joachim , Aigner Reingard , Maier Alfred , Lackner Carolin , Iberer Florian , Smolle‐Jüttner Freyja‐Maria , Tscheliessnigg Karlheinz , Stadlbauer Vanessa 
Published: October 2010

Stiegler P, Matzi V, Pierer E, Hauser O, Schaffellner S, Renner H, Greilberger J, Aigner R, Maier A, Lackner C, Iberer F, Smolle‐Jüttner F‐M, Tscheliessnigg K, Stadlbauer V. Creation of a prevascularized site for cell transplantation in rats. Xenotransplantation 2010; 17: 379–390. © 2010 John Wiley & Sons A/S.Abstract: Introduction:  Transplanted cells, especially islet cells, are likely to become apoptotic due to local hypoxia leading to graft dysfunction. Isolated pancreatic islet cells depend on the diffusion of oxygen from the surrounding tissue; therefore, access to sufficient oxygen supply is beneficial, particularly when microcapsules are used for immunoisolation in xenotransplantation. The aim of this study was to create a prevascularized site for cell transplantation in rats and test its effectiveness with microencapsulated HEK293 cells.Methods:  The combination of implantation of a foam dressing, vacuum‐assisted wound closure (foam+VAC) and hyperbaric oxygenation (HBO) was used in 40 Sprague‐Dawley rats. Blood flow and vascular endothelial growth factor (VEGF) levels were determined. Sodium cellulose sulphate (SCS)‐microencapsulated HEK293 cells were xenotransplanted into the foam dressing in rats pre‐treated with HBO, and angiogenesis and apoptosis were assessed.Results:  Vessel ingrowth and VEGF levels increased depending on the duration of HBO treatment. The area containing the foam was perfused significantly better in the experimental groups when compared to controls. Only a small amount of apoptosis occurs in SCS‐microencapsulated HEK293 cells after xenotransplantation.Conclusion:  As ischemia‐damaged cells are likely to undergo cell death or loose functionality due to hypoxia, therefore leading to graft dysfunction, the combination foam+VAC and HBO might be a promising method to create a prevascularized site to achieve better results in xenogeneic cell transplantation.
The immunology of corneal xenotransplantation: a review of the literature
Authors: Hara Hidetaka , Cooper David K. C. 
Published: October 2010

Hara H, Cooper DKC. The immunology of corneal xenotransplantation: a review of the literature. Xenotransplantation 2010; 17: 338–349. © 2010 John Wiley & Sons A/S.Abstract: As the worldwide demand for human donor corneas far exceeds supply, there is a need for a new source of corneas for clinical transplantation. Genetically engineered pigs may prove to be that new source, particularly as current evidence indicates that the anatomical and biomechanical properties of human and pig corneas are similar. Experience with clinical and experimental corneal xenotransplantation has been comprehensively reviewed and is summarized. Studies in small and large animal models have documented that both humoral and cellular immune responses play roles in xenograft rejection. Recent progress in the genetic manipulation of pigs has led to the prospect that clinical corneal xenotransplantation, in the absence of exogenous immunosuppressive therapy, may become successful in the foreseeable future.