bluuebunny/crossref_metadata_2025_split huggingface dataset:
Moving EM: the Rapid Transfer System as a new tool for correlative light and electron microscopy and high throughput for high‐pressure freezing
Authors: VERKADE P. 
Published: April 2008

SummaryIn this paper, the Rapid Transfer System (RTS), an attachment to the Leica EMPACT2 high‐pressure freezer, is described as a new tool for special applications within the cryofixation field. The RTS is an automated system that allows for fast processing of samples (<5 s) that make it possible for the first time to use high‐pressure freezing in combination with high time resolution correlative light and electron microscopy. In addition, with a working cycle of 30 s this rapid turn over time allows one to acquire more samples of biopsy material before it deteriorates than with other HPF machines with longer cycle times. With the use of the RTS it was possible to obtain three samples each of four different tissues in 6 min. Together with the finding that 90% of samples of cells grown on sapphire discs were well frozen, the RTS was both fast and reliable. Most important, together with other newly developed accessories, the RTS made it possible to capture specific events occurring live in the cell as observed by light microscopy, to cryofix that sample/event within 4 s, and then to analyze that event at high resolution in the electron microscope with excellent preservation of ultra‐structure. These developments should give us the tools to unravel intracellular processes that can be observed by live cell imaging but are too rare or fast to be picked up by routine EM methods or where the history of a structure is necessary to be able to discern its nature.
Cryptic speciation in a Holarctic passerine revealed by genetic and bioacoustic analyses
Authors: TOEWS DAVID P. L. , IRWIN DARREN E. 
Published: April 2008

AbstractThere has been much controversy regarding the timing of speciation events in birds, and regarding the relative roles of natural and sexual selection in promoting speciation. Here, we investigate these issues using winter wrens (Troglodytes troglodytes), an unusual example of a passerine with a Holarctic distribution. Geographical variation has led to speculation that the western North American formTroglodytes troglodytes pacificusmight be a distinct biological species compared to those in eastern North America (e.g.Troglodytes troglodytes hiemalis) and Eurasia. We located the first known area in which both forms can be found, often inhabiting neighbouring territories. Each male wren in this area sings either western or eastern song, and the differences in song are as distinct in the contact zone as they are in allopatry. The two singing types differ distinctly in mitochondrial DNA sequences and amplified fragment length polymorpism profiles. These results indicate that the two forms are reproductively isolated to a high degree where they co‐occur and are therefore separate species. DNA variation suggests that the initial split between the two species occurred before the Pleistocene, quite long ago for sister species in the boreal forest. Surprisingly, the two forms are similar in morphometric traits and habitat characteristics of territories. These findings suggest that sexual selection played a larger role than habitat divergence in generating reproductive isolation, and raise the possibility that there are other such morphologically cryptic species pairs in North America.
Outcrossing between an agroforestry plantation and remnant native populations of Eucalyptus loxophleba
Authors: SAMPSON JANE F. , BYRNE MARGARET 
Published: April 2008

AbstractGene dispersal among populations of a species is an important force influencing their genetic structure. Dispersal may also occur between taxa that would normally be isolated when nonendemic, domesticated or transgenic species are planted within the natural range of interfertile taxa. Such a mosaic of populations is typical of many agricultural landscapes, and investigations are needed to assess the risks of genetic contamination of the endemic populations but a combination of approaches may be necessary because of the limitations of research in this landscape. This study used microsatellite markers and a range of analyses (mating system, paternity exclusion, Bayesian assignment) to examine gene dispersal between remnants of the endemic Eucalyptus loxophleba ssp. supralaevis and a plantation of a nonendemic subspecies. Our results indicate that remnant populations are connected by significant dispersal to pollen sources up to 1.94 km away including the plantation. The combined analyses showed that the pollen pool and outcrossing rates of individuals within remnants varied significantly probably because of asynchronous flowering and that the likelihood of paternity was not correlated with spatial proximity. More than half of all progeny had male parents from outside their stand with the largest proportions estimated to come from the plantation by exclusion (42.4%) or Bayesian analyses (18.8–76%). Fragmentation may not be associated with decreased gene dispersal between populations of tree species, natural or planted, so that the distances required to buffer endemic trees in fragmented rural landscapes are likely to be large.
Leaf angle in Chenopodium album is determined by two processes: induction and cessation of petiole curvature
Authors: FUJITA KEIKO , TAKAGI SHINGO , TERASHIMA ICHIRO 
Published: April 2008

ABSTRACTPetiole curvature is important in regulating light interception by the leaf. To dissect the determination processes of leaf angle, we irradiated the lamina or petiole of Chenopodium album L. with either one or two spots of actinic light, after dark adaptation. When the abaxial side of the petiole was irradiated with blue light, the petiole curvature increased, and under continuous irradiation, the curvature continued for up to 6 h. The rate of curvature increased with increasing blue light intensity. The curvature induced by irradiation of the abaxial side with blue light ceased when the adaxial side of the petiole was simultaneously irradiated with either blue or red light. When an inhibitor for photosynthesis, 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea, was applied to the adaxial side of the petiole, the cessation of curvature caused by blue light was only weakly inhibited, while the cessation caused by red light was markedly inhibited. When the adaxial side of the petiole was irradiated alternately with red and far‐red light, the far‐red light antagonized the cessation of curvature caused by the red light. These results clearly show that the petiole curvature is controlled by two processes, the induction and the cessation of curvature. At least three photoreceptor systems, blue‐light receptor, photosynthesis and phytochrome, are involved in the reactions.
Historical tsunamis and storms recorded in a coastal lowland, Shizuoka Prefecture, along the Pacific Coast of Japan
Authors: KOMATSUBARA JUNKO , FUJIWARA OSAMU , TAKADA KEITA , SAWAI YUKI , AUNG THAN TIN , KAMATAKI TAKANOBU 
Published: April 2008

AbstractFour sand units deposited by tsunamis and one sand unit deposited by storm surge(s) were identified in a muddy marsh succession in a narrow coastal lowland along the Pacific coast of central Japan. Tsunamis in ad 1498, 1605, 1707 and 1854 that were related to large subduction‐zone earthquakes along the Nankai Trough, and storm surges in 1680 and/or 1699 were responsible for the deposition of these sand units. These sand units are distinguished by lithofacies, sedimentary structures, grain‐size and mineral composition, and radiocarbon ages; their ages are supported by events in local historical records. The tsunami deposits in the study area are massive or parallel‐laminated sands, with associated intraclasts, gravels, draping mud layers and, rarely, a return‐flow subunit. The storm surge deposits are devoid of these characteristics, and are composed of groups of thin, current ripple‐laminated sand layers. The differences in sedimentary structures between the tsunami and storm surge deposits are attributed to the different characteristics of tsunami and storm waves.
Ethylene–auxin interactions regulate lateral root initiation and emergence in Arabidopsis thaliana
Authors: Ivanchenko Maria G. , Muday Gloria K. , Dubrovsky Joseph G. 
Published: April 2008

SummaryPlant root systems display considerable plasticity in response to endogenous and environmental signals. Auxin stimulates pericycle cells within elongating primary roots to enter de novo organogenesis, leading to the establishment of new lateral root meristems. Crosstalk between auxin and ethylene in root elongation has been demonstrated, but interactions between these hormones in root branching are not well characterized. We find that enhanced ethylene synthesis, resulting from the application of low concentrations of the ethylene precursor 1‐aminocyclopropane‐1‐carboxylic acid (ACC), promotes the initiation of lateral root primordia. Treatment with higher doses of ACC strongly inhibits the ability of pericycle cells to initiate new lateral root primordia, but promotes the emergence of existing lateral root primordia: behaviour that is also seen in the eto1 mutation. These effects are correlated with decreased pericycle cell length and increased lateral root primordia cell width. When auxin is applied simultaneously with ACC, ACC is unable to prevent the auxin stimulation of lateral root formation in the root tissues formed prior to ACC exposure. However, in root tissues formed after transfer to ACC, in which elongation is reduced, auxin does not rescue the ethylene inhibition of primordia initiation, but instead increases it by several fold. Mutations that block auxin responses, slr1 and arf7 arf19, render initiation of lateral root primordia insensitive to the promoting effect of low ethylene levels, and mutations that inhibit ethylene‐stimulated auxin biosynthesis, wei2 and wei7, reduce the inhibitory effect of higher ethylene levels, consistent with ethylene regulating root branching through interactions with auxin.
Both ATM and ATR promote the efficient and accurate processing of programmed meiotic double‐strand breaks
Authors: Culligan Kevin M. , Britt Anne B. 
Published: April 2008

SummaryThe ATM and ATR protein kinases play central roles in the cellular response to double‐strand breaks (DSBs) by regulating DNA repair, cell‐cycle arrest and apoptosis. During meiosis, SPO11‐dependent DSBs are generated, initiating recombination between homologous chromosomes. Previous studies in mice and plants have shown that defects in ATM result in the appearance of abnormally fragmented chromosomes. However, the role of ATR in promoting normal meiosis has not yet been elucidated. Employing null Arabidopsis mutants of ATR and ATM, we demonstrate here that although atr mutants display no obvious defects in any phase of meiotic progression, the combination of defects in atr and atm exacerbates the fragmentation observed in the atm single mutant, prevents complete synapsis of chromosomes, and results in extensive and persistent interactions between non‐homologous DNAs. The observed non‐homologous interactions require the induction of programmed breaks: the combination of either the atm single or the atr atm double mutant with a spo11 defect eliminates the ectopic interactions observed in the double mutant, as well as significantly reducing the fragmentation seen in atm or in atr atm. Our results suggest that ATM is required for the efficient processing of SPO11‐dependent DSBs during meiosis. They also indicate that ATM and ATR act redundantly to inhibit sustained interactions between non‐homologous chromatids, and that these ectopic interactions require SPO11 activity.
The Medicago truncatula ortholog of Arabidopsis EIN2, sickle, is a negative regulator of symbiotic and pathogenic microbial associations
Authors: Varma Penmetsa R. , Uribe Pedro , Anderson Jonathan , Lichtenzveig Judith , Gish John‐Charles , Nam Young Woo , Engstrom Eric , Xu Kun , Sckisel Gail , Pereira Mariana , Baek Jong Min , Lopez‐Meyer Melina , Long Sharon R. , Harrison Maria J. , Singh Karam B. , Kiss Gyorgy B. , Cook Douglas R. 
Published: April 2008

SummaryThe plant hormone ethylene negatively regulates bacterial infection and nodule formation in legumes in response to symbiotic rhizobia, but the molecular mechanism(s) of ethylene action in symbiosis remain obscure. We have identified and characterized multiple mutant alleles of the MtSkl1 gene, which controls both ethylene sensitivity and nodule numbers. We show that this locus encodes the Medicago truncatula ortholog of the Arabidopsis ethylene signaling protein EIN2. In addition to the well‐characterized role of MtSkl1 in rhizobial symbiosis, we show that MtSkl1 is involved in regulating early phases of the symbiotic interaction with mycorrhizal fungi, and in mediating root responses to cytokinin. MtSkl1 also functions in the defense against Rhizoctonia solani and Phytophthora medicaginis, with the latter interaction likely to involve positive feedback amplification of ethylene biosynthesis. Overexpression of the C‐terminal domain of MtEIN2 is sufficient to block nodulation responses, consistent with previous reports in Arabidopsis on the activation of ethylene signaling. This same C‐terminal region is uniquely conserved throughout the EIN2 homologs of angiosperms, which is consistent with its role as a higher plant‐specific innovation essential to EIN2 function.
AtCYP38 ensures early biogenesis, correct assembly and sustenance of photosystem II
Authors: Sirpiö Sari , Khrouchtchova Anastassia , Allahverdiyeva Yagut , Hansson Maria , Fristedt Rikard , Vener Alexander V. , Scheller Henrik Vibe , Jensen Poul Erik , Haldrup Anna , Aro Eva‐Mari 
Published: April 2008

SummaryAtCYP38 is a thylakoid lumen protein comprising the immunophilin domain and the phosphatase inhibitor module. Here we show the association of AtCYP38 with the photosystem II (PSII) monomer complex and address its functional role using AtCYP38‐deficient mutants. The dynamic greening process of etiolated leaves failed in the absence of AtCYP38, due to specific problems in the biogenesis of PSII complexes. Also the development of leaves under short‐day conditions was severely disturbed. Detailed biophysical and biochemical analysis of mature AtCYP38‐deficient plants from favorable growth conditions (long photoperiod) revealed: (i) intrinsic malfunction of PSII, which (ii) occurred on the donor side of PSII and (iii) was dependent on growing light intensity. AtCYP38 mutant plants also showed decreased accumulation of PSII, which was shown not to originate from impaired D1 synthesis or assembly of PSII monomers, dimers and supercomplexes as such but rather from the incorrect fine‐tuning of the oxygen‐evolving side of PSII. This, in turn, rendered PSII centers extremely susceptible to photoinhibition. AtCYP38 deficiency also drastically decreased the in vivo phosphorylation of PSII core proteins, probably related to the absence of the AtCYP38 phosphatase inhibitor domain. It is proposed that during PSII assembly AtCYP38 protein guides the proper folding of D1 (and CP43) into PSII, thereby enabling the correct assembly of the water‐splitting Mn4–Ca cluster even with high turnover of PSII.
Skin reactivity and local cell recruitment in human atopic and nonatopic subjects by CCL2/MCP‐1 and CCL3/MIP‐1α
Authors: Gaga M. , Ong Y.‐E. , Benyahia F. , Aizen M. , Barkans J. , Kay A. B. 
Published: April 2008

Background:  Monocyte chemotactic protein (MCP‐1/CCL2), the ligand for CCR2 and CCR5, and macrophage inflammatory protein‐1α (MIP‐1α/CCL3), the ligand for CCR1 and CCR5, are potent chemo‐attractants in vitro and produce lesions in experimental animals, which resemble immediate and delayed‐type hypersensitivity (DTH) reactions. CCL3 induces mononuclear cell and granulocyte infiltration in human atopic and nonatopic skin. Whether CCL2 (MCP‐1) has comparable activity in man is uncertain as is the capacity of both the chemokines to elicit immediate‐ and DTH‐like reactions in humans.Methods:  Inflammatory cells were counted by immunohistochemistry in 24 and 48‐h skin biopsies from atopics and nonatopics after intradermal injection of CCL2 and CCL3. Immediate (15 min) wheals‐and‐flares and delayed (24 and 48 h) indurations were also recorded.Results:  Both chemokines induced immediate‐ (15 min) and delayed (24 and 48 h) reactions, which were associated with significant infiltrations of CD68+ macrophages, CD3+, CD4+ (but not CD8+) T cells, neutrophils, and eosinophils in biopsies from injection sites. CCL2, but not CCL3, also induced infiltration of basophils. Neither chemokine produced significant changes in the numbers of tryptase+ cutaneous mast cells. There were no differences in the pattern of skin reactivity or the numbers of infiltrating leukocytes in response to CCL2 and CCL3 between atopic and nonatopic subjects. In general, maximal infiltration of inflammatory cells was observed at the 24‐h, rather than the 48‐h, time point.Conclusions:  CCL2 and CCL3 induce both immediate and delayed skin reactions in atopics and nonatopics, and evoke a similar profile of local T cell/macrophage and granulocyte recruitment which, in general, confirm previous in vitro findings and in vivo experimental animal data.
Distribution of Langerhans cells and mast cells within the human oral mucosa: new application sites of allergens in sublingual immunotherapy?
Authors: Allam J.‐P. , Stojanovski G. , Friedrichs N. , Peng W. , Bieber T. , Wenzel J. , Novak N. 
Published: April 2008

Background:  Sublingual immunotherapy (SLIT) represents an alternative to subcutaneous immunotherapy. While antigen‐presenting cells such as Langerhans cells (LCs) are thought to contribute to the effectiveness of SLIT, mast cells (MCs) most likely account for adverse reactions such as sublingual edema. As little is known about LCs and MCs within the oral cavity, we investigated their distribution in search for mucosal sites with highest LCs and lowest MCs density.Methods:  Biopsies were taken simultaneously from human vestibulum, bucca, palatum, lingua, sublingua, gingiva, and skin. Immunohistochemistry and flow cytometry were used to detect MCs, LCs and high affinity receptor for IgE (FcεRI) expression of LCs. Mixed lymphocyte reactions were performed to assess their stimulatory capacity.Results:  Highest density of MCs was detected within the gingiva, while the lowest density of MCs was found within the palatum and lingua. However, sublingual MCs were located within glands, which might explain swelling of sublingual caruncle in some SLIT patients. Highest density of LCs was detected within the vestibular region with lowest density in sublingual region. Highest expression of FcεRI was detected on LCs within the vestibulum. Furthermore LCs from different regions displayed similar stimulatory capacity towards allogeneic T cells.Conclusions:  In view of our data, different mucosal regions such as the vestibulum might represent alternative SLIT application sites with potent allergen uptake. Our data might serve as a basis for new application strategies for SLIT to enhance efficiency and reduce local adverse reactions.
Proactive treatment of atopic dermatitis in adults with 0.1% tacrolimus ointment
Authors: Wollenberg A. , Reitamo S. , Girolomoni G. , Lahfa M. , Ruzicka T. , Healy E. , Giannetti A. , Bieber T. , Vyas J. , Deleuran M. ,   for the European Tacrolimus Ointment Study Group
Published: April 2008

Background:  Long‐term treatment for atopic dermatitis (AD) using low dose, intermittent, topical anti‐inflammatory agents may control acute disease and prevent relapses. This 12‐month, European, multicentre, randomized study investigated whether the proactive use of 0.1% tacrolimus ointment applied twice weekly can keep AD in remission and reduce the incidence of disease exacerbations (DE).Methods:  During the initial open‐label period, 257 adults with AD applied 0.1% tacrolimus ointment twice daily (b.i.d.) for up to 6 weeks to affected areas. When an Investigator Global Assessment (IGA) score of ≤2 was achieved, the patient entered the disease control period (DCP) and was randomized to either proactive tacrolimus (n = 116) or vehicle ointment (n = 108) twice weekly for 12 months. Exacerbations were treated with 0.1% tacrolimus ointment b.i.d. until an IGA ≤2 was regained, then randomized treatment was restarted. The primary endpoint was the number of DEs during the DCP that required a substantial therapeutic intervention.Results:  Proactive tacrolimus 0.1% ointment application significantly reduced the number of DEs requiring substantial therapeutic intervention (median difference 2; P < 0.001; Wilcoxon rank sum test), the percentage of DE treatment days (median difference: 15.2%; P < 0.001; Wilcoxon rank sum test) and increased the time to first DE (median 142 vs 15 days; P < 0.001; stratified log‐rank test). The adverse event profile was similar for the two treatment approaches.Conclusion:  A 12‐month, twice weekly proactive tacrolimus ointment application was an effective treatment in most study patients which prevented, delayed and reduced the occurrence of AD exacerbations.
How to assess disease activity in patients with chronic urticaria?
Authors: Młynek A. , Zalewska‐Janowska A. , Martus P. , Staubach P. , Zuberbier T. , Maurer M. 
Published: April 2008

Background: The current EAACI/GA²LEN/EDF guidelines recommend assessing disease activity in chronic urticaria (CU) by using an established and well‐defined symptom score, i.e. the urticaria activity score (UAS), which combines daily wheal numbers and pruritus intensity. However, this UAS has never been formally tested for its suitability in assessing CU activity.Aim: To determine the UAS correlation with quality of life (QoL) in CU patients and to compare the UAS to other symptom scores.Methods: Chronic urticaria symptoms (wheals, erythema, angioedema, pruritus) were assessed on seven consecutive days in 111 CU patients for their numbers, duration, size, and/or intensity. Quality of life was assessed by using the Dermatology Life Quality Index. Both, urticaria activity and QoL were determined before and after a 3‐week period, in which the patients followed a pseudoallergen‐low diet.Results: Urticaria activity score values correlated positively, albeit weakly, with QoL impairment in CU patients (r2 = 0.31, P < 0.05). Also, changes in QoL following a pseudoallergen‐low diet were reflected by the changes observed in the UAS (r2 = 0.30, P < 0.05). No significant differences were found comparing the QoL correlation of the UAS and other symptom scores combining up to four CU symptom qualities. Quality of life correlation with UAS values increased with the number of days the UAS was assessed and plateaued starting from the fourth consecutive day.Conclusions: Our findings back the current guideline recommendations to use the UAS for monitoring disease activity in CU patients. Urticaria activity score mean values of at least four consecutive days should be used.