bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of wholemount mouse intestine for high‐resolution three‐dimensional imaging using two‐photon microscopy
Authors: APPLETON P.L. , QUYN A.J. , SWIFT S. , NÄTHKE I. 
Published: April 2009

SummaryVisualizing overall tissue architecture in three dimensions is fundamental for validating and integrating biochemical, cell biological and visual data from less complex systems such as cultured cells. Here, we describe a method to generate high‐resolution three‐dimensional image data of intact mouse gut tissue. Regions of highest interest lie between 50 and 200 μm within this tissue. The quality and usefulness of three‐dimensional image data of tissue with such depth is limited owing to problems associated with scattered light, photobleaching and spherical aberration. Furthermore, the highest‐quality oil‐immersion lenses are designed to work at a maximum distance of ≤10–15 μm into the sample, further compounding the ability to image at high‐resolution deep within tissue. We show that manipulating the refractive index of the mounting media and decreasing sample opacity greatly improves image quality such that the limiting factor for a standard, inverted multi‐photon microscope is determined by the working distance of the objective as opposed to detectable fluorescence. This method negates the need for mechanical sectioning of tissue and enables the routine generation of high‐quality, quantitative image data that can significantly advance our understanding of tissue architecture and physiology.
The relation between stomatal aperture and gas exchange under consideration of pore geometry and diffusional resistance in the mesophyll
Authors: KAISER HARTMUT 
Published: April 2009

ABSTRACTThe quantitative relation between stomatal aperture and gas exchange through the stomatal pore can be described by physical models derived from Fick's first law of diffusion. Such models, usually based on a simplified pore geometry, are used to calculate leaf conductance from stomatal pore dimensions or vice versa. In this study a combination of gas‐exchange measurements and simultaneous microscopical observations of stomatal apertures was used to empirically determine this relationship. The results show a substantial deviation between measured stomatal conductance and that calculated from the simplified models. The main difference is a much steeper increase of conductance with aperture at small apertures. When the calculation was based on a realistic pore geometry derived from confocal laser scanning microscopy, a good fit to the experimentally found relationship could be obtained if additionally a significant contribution of a mesophyll diffusional resistance was taken into account.
Frost tolerance in excised leaves of the common bugle (Ajuga reptans L.) correlates positively with the concentrations of raffinose family oligosaccharides (RFOs)
Authors: PETERS SHAUN , KELLER FELIX 
Published: April 2009

ABSTRACTMass increases in raffinose family oligosaccharides (RFOs, α1,6‐galactosyl extensions of sucrose) are well documented in the generative tissues of many plants upon cold acclimation, and they (i.e. mainly the two shortest RFO members, raffinose and stachyose) have been suggested as frost stress protectants. Our focus here was on the longer RFO members as they commonly occur in the frost‐hardy evergreen labiate Ajuga reptans in its natural habitat, and accumulate to their highest concentrations in winter when the plant is faced with sub‐zero temperatures. We examined the effects of RFO concentration and chain length on frost tolerance using excised leaves which accumulate long‐chain RFOs under both cold and warm conditions, thereby uncoupling the acclimation temperature from RFO production. We demonstrated that frost tolerance in excised A. reptans leaves correlates positively with long‐chain RFO accumulation under both acclimation temperatures. After 24 d post‐excision in the warm, the leaves had increased their RFO concentrations (mainly long‐chain RFOs) 22‐fold to 78 mg g−1 fresh weight, and decreased their EL50 values (temperature at which 50% leakage occurred) from −10.5 to −24.5 °C, suggesting a protective role for these oligosaccharides in the natural frost tolerance of A. reptans.
Metabolic flux analysis in plants: coping with complexity
Authors: ALLEN DOUG K. , LIBOUREL IGOR G. L. , SHACHAR‐HILL YAIR 
Published: April 2009

ABSTRACTTheory and experience in metabolic engineering both show that metabolism operates at the network level. In plants, this complexity is compounded by a high degree of compartmentation and the synthesis of a very wide array of secondary metabolic products. A further challenge to understanding and predicting plant metabolic function is posed by our ignorance about the structure of metabolic networks even in well‐studied systems. Metabolic flux analysis (MFA) provides tools to measure and model the functioning of metabolism, and is making significant contributions to coping with their complexity.This review gives an overview of different MFA approaches, the measurements required to implement them and the information they yield. The application of MFA methods to plant systems is then illustrated by several examples from the recent literature. Next, the challenges that plant metabolism poses for MFA are discussed together with ways that these can be addressed. Lastly, new developments in MFA are described that can be expected to improve the range and reliability of plant MFA in the coming years.
Dynamics of vacuoles and actin filaments in guard cells and their roles in stomatal movement
Authors: GAO XIN‐QI , WANG XIU‐LING , REN FEI , CHEN JIA , WANG XUE‐CHEN 
Published: April 2009

ABSTRACTVacuoles and actin filaments are important cytoarchitectures involved in guard cell function. The changes in the morphology and number of vacuoles and the regulation of ion channel activity in tonoplast of guard cells are essential for stomatal movement. A number of studies have investigated the regulation of ion channels in animal and plant cells; however, little is known about the regulating mechanism for vacuolar dynamics in stomatal movement. Actin filaments of guard cells are remodelling with the changes in the stomatal aperture; however, the dynamic functions of actin filaments in stomatal movement remain elusive. In this paper, we summarize the recent developments in the understanding of the dynamics of actin filaments and vacuoles of guard cells during stomatal movement. All relevant studies suggest that actin filaments might be involved in stomatal movement by regulating vacuolar dynamics and the ion channels in tonoplast. The future study could be focused on the linker protein mediating the interaction between actin filaments and tonoplast, which will provide insights into the interactive function of actin and vacuole in stomatal movement regulation.
GhDREB1 enhances abiotic stress tolerance, delays GA‐mediated development and represses cytokinin signalling in transgenic Arabidopsis
Authors: HUANG JIN‐GUANG , YANG MEI , LIU PEI , YANG GUO‐DONG , WU CHANG‐AI , ZHENG CHENG‐CHAO 
Published: April 2009

ABSTRACTPlants vary significantly in their ability to tolerate low temperatures. The CBF/DREB1 cold response pathway has been identified in many plant species and plays a pivotal role in low temperature tolerance. Here, we show that GhDREB1 is a functional homologue and elevates the freezing, salt and osmotic stress tolerance of transgenic Arabidopsis. The constitutive expression of GhDREB1 in Arabidopsis caused dwarfism and late flowering phenotypes, which could be rescued by exogenous application of GA3. Endogenous bioactive GA contents were significantly lower in GhDREB1 overexpressing Arabidopsis than in wild‐type plants. RT‐PCR analyses revealed that the transcript levels of the GA synthase genes were higher in transgenics than in wild‐type plants, whereas the GA deactivating genes were lower. Flowering related genes in different regulatory pathways were also affected by GhDREB1, which may account for the flowering delay phenotype. Moreover, the GhDREB1 overexpressing Arabidopsis exhibited decreased sensitivity to cytokinin (CK) which is associated with repression of expression of type‐B and type‐A ARRs, two key components in the CK‐signalling pathway.
High‐frequency cyclicity (Milankovitch and millennial‐scale) in slope‐apron carbonates: Zechstein (Upper Permian), North‐east England
Authors: MAWSON MIKE , TUCKER MAURICE 
Published: April 2009

AbstractThe Upper Permian (Zechstein) slope carbonates in the Roker Formation (Zechstein 2nd‐cycle Carbonate) in North‐east England consist of turbidites interbedded with laminated lime‐mudstone. Studies of turbidite bed thickness and relative proportion of turbidites (percentage turbidites in 20 cm of section) reveal well‐developed cyclicities consisting of thinning‐upward and thickening‐upward packages of turbidite beds. These packages are on four scales, from less than a metre, up to 50 m in thickness. Assuming that the laminae of the hemipelagic background sediment are annual allows the durations of the cycles to be estimated. In addition, counting the number and thickness of turbidite beds in 20 cm of laminated lime‐mudstone, which is approximately equivalent to 1000 years (each lamina is 200 μm), gives the frequencies of the turbidite beds, the average thicknesses and the overall sedimentation rates through the succession for 1000 year time‐slots. Figures obtained are comparable with modern rates of deposition on carbonate slopes. The cyclicity present in the Roker Formation can be shown to include: Milankovitch‐band ca 100 kyr short‐eccentricity, ca 20 kyr precession and ca 10 kyr semi‐precession cycles and sub‐Milankovitch millennial‐scale cycles (0·7 to 4·3 kyr). Eccentricity and precession‐scale cycles are related to ‘highstand‐shedding’ and relative sea‐level change caused by Milankovitch‐band orbital forcing controlling carbonate productivity. The millennial‐scale cycles, which are quasi‐periodic, probably are produced by environmental changes controlled by solar forcing, i.e. variations in solar irradiance, or volcanic activity. Most probable here are fluctuations in carbonate productivity related to aridity–humidity and/or temperature changes. Precession and millennial‐scale cycles are defined most strongly in early transgressive and highstand parts of the larger‐scale short‐eccentricity cycles. The duration of the Roker Formation as a whole can be estimated from the thickness of the laminated lithotype as ca 0·3 Myr.
A quantitative analysis of temperature‐dependent dormancy changes inPolygonum aviculareseeds
Authors: BATLLA D , GRUNDY A , DENT K C , CLAY H A , FINCH‐SAVAGE W E 
Published: April 2009

SummaryMathematical models that predict emergence of weed seedbanks could be useful tools for determining the most suitable time for weed seedling control and, consequently, should result in a higher efficacy of applied control methods. To achieve this goal in dormant weed species, functional relationships should be established between environmental factors regulating dormancy and dormancy changes of seed populations. In the present work, we used a simple model and an optimisation procedure to quantify the effect of temperature onPolygonum aviculareseed dormancy release and induction, based on germination data. Dormancy release rate was inversely related to temperature, showing a decreasing logistic trend that results in no dormancy release for seeds exposed to 20 and 25°C. In contrast, dormancy induction rates in absolute values were positively associated with temperature, showing a logistic trend in which dormancy induction was almost zero at low temperatures and maximal at 25°C. Derived model parameters were used to simulate dormancy changes ofP. aviculareseeds stored under controlled and field conditions. These results suggest that similar model structures could be used to quantify temperature effects on seed dormancy status of other weed species and to develop predictive models of weed emergence.
The efficiency of a vacuum device for estimating soil‐surface seed abundance on lowland farms
Authors: EVANS D M , MCLEOD J J , PASCOE L , MEMMOTT J 
Published: April 2009

SummaryAccurate sampling methods for estimating soil‐surface seed abundance in agro‐ecosystems are vital for understanding arable plant population dynamics, as well as quantifying seed availability as a food resource for farmland birds, mammals and arthropods. We tested the sampling efficiency of a portable, petroleum spirit powered leaf blower‐vacuum in recovering four different seed size classes on the soil‐surface of seven lowland farm habitats. Vacuum sampler efficiency was dependent on seed size, habitat type and exposure of seeds to environmental conditions. Larger seeds were more readily recovered and overall seed recovery was consistently higher on habitats with low vegetation cover, such as newly‐sown cereal fields. We discuss the limitations of the device, but commend its use with correction factors to estimate soil‐surface seed abundance in agricultural habitats. This study highlights the potential biases when estimating soil‐surface seed abundance, the importance of correcting such biases and the need for better sampling techniques for weed science.
Time trends of co‐existing atopic conditions in Singapore school children: prevalence and related factors
Authors: Wang Xiao Shan , Shek Lynette P. , Ma Stefan , Soh Shu E , Lee Bee Wah , Goh Daniel Y. T. 
Published: April 2009

Wang XS, Shek LP, Ma S, Soh SE, Lee BW, Goh DYT. Time trends of co‐existing atopic conditions in Singapore school children: prevalence and related factors. Pediatr Allergy Immunol 2010: 21: e137–e141. © 2009 The Authors Journal compilation © 2009 Blackwell MunksgaardAtopic diseases are known to co‐exist and are interrelated. Their co‐existence in a patient increases disease burden and morbidity. We sought to study the prevalence of co‐existing atopic conditions over time and its associated risk factors among Singapore children. Data was collected from two respective The International Study of Asthma and Allergies in Childhood surveys conducted in 1994 and 2001. Data on asthma, rhinitis and eczema were obtained from the responses to questions about wheezing, exercise‐induced wheezing, nocturnal cough, rhinitis symptoms, rash, and diagnoses of asthma, rhinitis and eczema in the last 12 months. Data on demographic and known risk factors were also obtained. The prevalence of children who have had more than one atopic disorder increased significantly from 6.0% in 1994 to 10.2% in 2001 (p < 0.001). Parental history of atopic disease, maternal educational level, male gender and smoke exposure were significantly associated with co‐existent atopic symptoms in the child. Among Singapore schoolchildren, there was a significant prevalence of co‐existent atopic disease and this prevalence was rising. The influences of both genetic and environmental factors were likely to have contributed to these observations.
Distribution and expression of porcine endogenous retroviruses in multi‐transgenic pigs generated for xenotransplantation
Authors: Dieckhoff Britta , Kessler Barbara , Jobst Danny , Kues Wilfried , Petersen Björn , Pfeifer Alexander , Kurth Reinhard , Niemann Heiner , Wolf Eckhard , Denner Joachim 
Published: April 2009

Abstract:Background:  Multi‐transgenic pigs produced for use in xenotransplantation have to be screened for the presence and expression of porcine endogenous retroviruses (PERV) to select animals with low PERV load. The production of transgenic pigs may also be associated with the integration of the transgene adjacent to or into the locus of a PERV provirus, potentially leading to an enhanced virus expression.Methods:  Non‐transgenic animals, single‐transgenic, and multi‐transgenic pigs were screened for the presence of PERV‐A, ‐B, and ‐C and recombinant PERV‐A/C using polymerase chain reaction (PCR). PERV expression was determined by real time reverse transcriptase‐PCR. An assay based on the activation of PERV in peripheral blood mononuclear cells by mitogens was used to discriminate between low and high PERV producer animals.Results:  All animals carried PERV‐A and ‐B. A total of 176 from 181 (97.2%) animals carried PERV‐C in the germ line and 18 from 64 animals carried PERV‐A/C in the genome of lymphoid cells but not in the germ line. The expression of PERV was very low in all animals and not different between transgenic pigs and non‐transgenic animals. PERV expression differed between various pig lines. The highest expression was found in mini‐pigs and crossing other pig lines with mini‐pigs resulted in increased PERV expression in the progeny. However, expression of viral proteins and particle release were not observed in all transgenic animals.Conclusions:  No evidence for elevated PERV expression in (multi‐) transgenic pigs was observed. Differences in PERV expression correlated with the genetic background of the animals, not with the specific transgene. Mini‐pigs consistently had the highest level of PERV expression and animals with a mini‐pig background had a higher level of expression compared with animals without mini‐pig background.
In vitro and in vivo effects of the carbon monoxide‐releasing molecule, CORM‐3, in the xenogeneic pig‐to‐primate context
Authors: Vadori Marta , Seveso Michela , Besenzon Federica , Bosio Erika , Tognato Elena , Fante Fabio , Boldrin Massimo , Gavasso Sabrina , Ravarotto Licia , Mann Brian E. , Simioni Paolo , Ancona Ermanno , Motterlini Roberto , Cozzi Emanuele 
Published: April 2009

Abstract: Background:  Carbon monoxide (CO) interferes with inflammatory and apoptotic processes associated with ischemia–reperfusion injury and graft rejection. Here, the in vitro effects of carbon monoxide releasing molecule‐3 (CORM‐3), a novel water‐soluble carbonyl CO carrier, have been investigated on porcine aortic endothelial cells (PAEC) and primate peripheral blood mononuclear cells (PBMC). Furthermore, the pharmacodynamics and pharmacotolerance of CORM‐3 after administration of single and multiple doses in the primate have been assessed in view of its potential application in pig‐to‐primate xenotransplantation models.Methods:  For in vitro studies, PAEC and primate PBMC were exposed for 24, 48 and 72 h to CORM‐3 (20 to 1000 μm) and viability was measured using an MTS assay. PAEC and primate PBMC proliferation after exposure to CORM‐3 was assessed by CFSE labelling. Proliferation of primate PBMC against irradiated pig lymphocytes was also assessed. Tumor necrosis factor alpha (TNF‐α) production and Caspase‐3 and ‐7 activity in Concanavalin A (conA)‐stimulated primate PBMC were measured following treatment with CORM‐3. In vivo, CORM‐3 was administered i.v. to cynomolgus monkeys at 4 mg/kg, as single or multiple doses for up to 30 days. The effect of CORM‐3 was evaluated by the assessment of production of TNF‐α and interleukin 1β following PBMC stimulation with LPS by species‐specific ELISA. Complete hematologic and biochemical analyses were routinely performed in treated primates.Results:  At concentrations <500 μm, CORM‐3 did not alter the viability of PAEC or primate PBMC cultures in vitro, nor did it induce significant levels of apoptosis or necrosis. Interestingly, at concentrations of 300 and 500 μm, significant PAEC proliferation was observed, whilst concentrations ≥50 μm inhibited conA‐activated primate lymphocyte proliferation (IC50 of 345.8 ± 51.9 μm) and the primate xenogeneic response against pig PBMC. Such responses were demonstrated to be CO‐dependent. In addition, CORM‐3 significantly inhibited caspase‐3 and ‐7 activity at concentrations between 200 and 500 μm and caused a significant reduction in TNF‐α production (IC50 332.8 ± 33.9 μm). In vivo, following the administration of multiple doses, TNF‐α production was significantly reduced in comparison to pre‐treatment responses, with decreased levels maintained throughout the study. Moreover, a slight and transient increase in transaminases and bilirubin was observed in animals exposed to multiple doses of CORM‐3.Conclusions:  These studies suggest that CORM‐3 has anti‐inflammatory and immunomodulatory properties in primates that may result in clinical benefit to allo‐ and xenografted organs.
Concise semiquantitative histological scoring system for immunoglobulin A nephropathy
Authors: JIANG LEI , LIU GANG , LV JICHENG , HUANG CHAOXING , CHEN BO , WANG SUXIA , ZOU WANZHONG , ZHANG HONG , WANG HAIYAN 
Published: April 2009

SUMMARY:Aim:  Immunoglobulin A nephropathy (IgAN) is a common and progressive glomerulonephritis. Histological lesions of IgAN are variable and considered as a risk factor for renal outcome. Establishing a relatively concise histological semiquantitative scoring system would be valuable in clinical practice.Methods:  Renal biopsy sections of 293 patients with primary IgAN from two centres in China were reviewed. A histological scoring system was established based on multivariate survival analysis of semiquantitative histological indices, using end‐stage renal disease (ESRD) as the end‐point event.Results:  Four indices – extracapillary glomerular activity index (exGAI), mesangial proliferation index (MsI), glomerular chronicity index (GCI) and tubulointerstitial chronicity index (TCI) – independently correlated with ESRD (relative risk (RR) = 1.16, 2.27, 1.29 and 1.80, respectively). The four indices and the sum of their scores (Total I) constituted the scoring system. Patients with exGAI of 4 or more, GCI of 4 or more, MsI of 2 or more and TCI of 2 or more were considered as having a higher risk for progression (P < 0.05). A score of 4 or more on the exGAI index could identify the patients who should be treated with immunosuppressive drugs, which showed a lower incidence of ESRD than that without (24.3% vs 52.4%, P = 0.031).Conclusion:  It suggested that the present concise scoring system could serve as prognostic and therapeutic indications.
Revaccination of bone marrow transplant recipients: a review of current practices in Australia
Authors: Torda Adrienne , Alexander J. 
Published: April 2009

AbstractBackground: Vaccination following bone marrow transplant (BMT) is an important part of ongoing care and disease prevention. The aim of the study was to investigate vaccination procedures in BMT recipients and identify what systems are in place throughout Australia to remind and alert patients concerning their need for vaccination.Methods: Questionnaires were sent to haematologists managing BMT recipients in Australia to examine post‐BMT vaccination practices in hospitals and outpatient clinics. Questionnaires were also sent to BMT recipients in New South Wales, who had their transplants (either allogeneic or autologous) in the past 5 years to determine what vaccinations they had received and what vaccination reminder systems had been used.Results: Vaccine recommendations and practices by BMT physicians showed little consensus. They also differed greatly between autologous and allogeneic transplant recipients. Only just more than half of the physicians had an effective reminder system in place and only 12 of 34 patients had received vaccination reminders. One‐third of all patients were not aware of any need for revaccination.Conclusion: The disparity in physician practice regarding revaccination is significant and may reflect the lack of data available regarding efficacy of revaccination in this setting and/or a lack of knowledge about recommendations. Because of this, a national immunization schedule for post‐BMT patients founded on evidence‐based studies is required to provide optimal patient care. The lack of effective follow up and reminder systems ensuring patient completion of vaccination schedules is also an area needing improvement.