bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced viral clearance in interleukin‐18 gene‐deficient mice after pulmonary infection with influenza A virus
Authors: Van Der Sluijs Koenraad F. , Van Elden Leontine J. R. , Arens Ramon , Nijhuis Monique , Schuurman Rob , Florquin Sandrine , Kwakkel Joan , Akira Shizuo , Jansen Henk M. , Lutter René , Van Der Polls Tom 
Published: December 2004

SummaryT helper 1 driven immune responses facilitate host defence during viral infections. Because interleukin‐18 (IL‐18) mediates T helper 1 driven immune responses, and since mature IL‐18 is up‐regulated in human macrophages after influenza virus infection in vitro, it has been suggested that IL‐18 plays an important role in the immune response to influenza. To determine the role of IL‐18 in respiratory tract infection with influenza, IL‐18 gene‐deficient (IL‐18–/–) and normal wildtype mice were intranasally inoculated with influenza A virus. Influenza resulted in an increase in constitutively expressed IL‐18 in the lungs of wildtype mice. The clearance of influenza A was inhibited by IL‐18, as indicated by reduced viral loads on day 8 and day 12 after infection in IL‐18–/– mice. This enhanced viral clearance correlated with increased CD4+ T‐cell activation in the lungs as reflected by CD69 expression on the cell surface. Surprisingly, interferon‐γ (IFN‐γ) levels were similar in the lungs of IL‐18–/– mice and wildtype mice. Intracellular IFN‐γ staining revealed similar expression levels in lung‐derived natural killer cells, CD4+ and CD8+ T cells, indicating that IFN‐γ production is IL‐18‐independent during influenza virus infection. Tumour necrosis factor‐α production by CD4+ T cells was significantly lower in IL‐18–/– mice than in wildtype mice. Our data indicate that endogenous IL‐18 impairs viral clearance during influenza A infection.
The role of chemokines and extracellular matrix components in the migration of T lymphocytes into three‐dimensional substrata
Authors: Ivanoff Jyrki , Talme Toomas , Sundqvist Karl‐Gösta 
Published: December 2004

SummaryThe role of chemokines and their interactions with extracellular matrix components (ECM) or the capacity of T cells to migrate into and accumulate within three‐dimensional (3D) collagen type 1 substrata was studied. We examined the influence of chemokines and fibronectin on the infiltration properties of non‐infiltrative (do not migrate into 3D substrata) and spontaneously infiltrative (migrate into 3D substrata) T‐cell lines. Infiltrative and non‐infiltrative T‐acute lymphocytic leukaemic cell lines exhibited no consistent differences with respect to the expression of various chemokine receptors or β1‐integrins. Chemokines presented inside the collagen increased the depth of migration of infiltrative T‐cell lines, but did not render non‐infiltrative T‐cell lines infiltrative, although they augmented the attachment of non‐infiltrative T‐cell lines to the upper surface of the collagen. The presence of fibronectin inside the collagen did not render non‐infiltrative T‐cell lines infiltrative, but markedly augmented the migration of ‘infiltrative’ T‐cell lines into collagen. Both infiltrative and non‐infiltrative T‐cell lines showed migratory responses to chemokines in Boyden assays (migration detected on 2D substrata). These results indicate that the process of T‐cell infiltration/migration into 3D substrata depends on a tissue penetration mechanism distinguishable from migration on 2D substrata and that the basic capacity of T cells to infiltrate is independent of chemokines and ECM components applied as attractants.
Age‐related loss of naïve T cells and dysregulation of T‐cell/B‐cell interactions in human lymph nodes
Authors: Lazuardi Lutfan , Jenewein Brigitte , Wolf Anna Maria , Pfister Gerald , Tzankov Alexandar , Grubeck‐Loebenstein Beatrix 
Published: December 2004

SummaryIn this study we analysed the effects of age on T and B lymphocytes in human lymph nodes by comparing lymphocyte subsets in paraffin sections from lymph node tissue taken from healthy young and elderly people. We demonstrate that the relative number of CD8+ T cells decreases with age but that the relative number of CD4+ T cells does not. There is also a very pronounced age‐dependent loss of CD45RA+ naïve T cells. The number and size of follicles and the relative number of CD20+ B cells are similar in young and elderly donors. For polymerase chain reaction analysis of the T‐cell receptor (TCR) repertoire the TCR‐γ gene rearrangements were used as a marker of clonality. This is a reliable tool to detect not only clonal TCR‐γδ populations but also TCR‐αβ populations. Young donors with clonal T‐cell expansions in their lymph node tissue do, however, have a higher number of CD20+ B cells, a higher relative size of germinal centres compared to the follicle mantles and a higher number of immunoglobulin M‐expressing cells than young donors without evidence of clonal T‐cell expansions. Corresponding changes are not observed in elderly donors with clonal T‐cell expansions in their lymph node tissue. In summary our findings demonstrate characteristic effects of aging on human lymph node tissue, the most striking feature being the depletion of naïve T cells and the apparent dysregulation of T‐cell/B‐cell interactions in old age.
Analysis of the proteins targeted by CDSP32, a plastidic thioredoxin participating in oxidative stress responses
Authors: Rey Pascal , Cuiné Stéphan , Eymery Françoise , Garin Jérome , Court Magali , Jacquot Jean‐Pierre , Rouhier Nicolas , Broin Mélanie 
Published: December 2004

SummaryThe chloroplastic drought‐induced stress protein of 32 kDa (CDSP32) is a thioredoxin induced by environmental stress conditions. To gain insight into the function of CDSP32, we applied two strategies to analyze its targets. First, using affinity chromatography with an immobilized CDSP32 active site mutant, we identified six plastidic targets of CDSP32. Three of them are involved in photosynthetic processes: ATP‐aseγ‐subunit, Rubisco and aldolase. The three others participate in the protection against oxidative damage: two peroxiredoxins, PrxQ and the BAS1 2‐Cys peroxiredoxin, and a B‐type methionine sulfoxide reductase. Then, we developed a novel strategy to trap targets directly in leaf extracts. The method, based on co‐immunoprecipitation using extracts from plants overexpressing Wt CDSP32 or CDSP32 active site mutant, confirmed the interactionin vivobetween CDSP32 and the PrxQ and BAS1 peroxiredoxins. We showed that CDSP32 is able to form heterodimeric complexes with PrxQ and that the peroxiredoxin displays CDSP32‐dependent peroxidase activity. Under photooxidative stress induced by methyl viologen, plants overexpressing CDSP32 active site mutant exhibit decreased maximal PSII photochemical efficiency and retain much less chlorophyll compared with Wt plants and with plants overexpressing Wt CDSP32. We propose that the increased sensitivity results from trappingin plantaof the targets involved in the protection against oxidative damage. We conclude that CDSP32, compared with other plant thioredoxins, is a thioredoxin more specifically involved in plastidic responses against oxidative stress.
Abscisic acid and 14‐3‐3 proteins control K+ channel activity in barley embryonic root
Authors: van den Wijngaard Paul W.J. , Sinnige Mark P. , Roobeek Ilja , Reumer Annet , Schoonheim Peter J. , Mol Jos N.M. , Wang Mei , De Boer Albertus H. 
Published: December 2004

SummaryGermination of seeds proceeds in general in two phases, an initial imbibition phase and a subsequent growth phase. In grasses like barley, the latter phase is evident as the emergence of the embryonic root (radicle). The hormone abscisic acid (ABA) inhibits germination because it prevents the embryo from entering and completing the growth phase. Genetic and physiological studies have identified many steps in the ABA signal transduction cascade, but how it prevents radicle elongation is still not clear. For elongation growth to proceed, uptake of osmotically active substances (mainly K+) is essential. Therefore, we have addressed the question of how the activity of K+ permeable ion channels in the plasma membrane of radicle cells is regulated under conditions of slow (+ABA) and rapid germination (+fusicoccin). We found that ABA arrests radicle growth, inhibits net K+ uptake and reduces the activity of K+in channels as measured with the patch‐clamp technique. In contrast, fusicoccin (FC), a well‐known stimulator of germination, stimulates radicle growth, net K+ uptake and reduces the activity of K+out channels. Both types of channels are under the control of 14‐3‐3 proteins, known as integral components of signal transduction pathways and instrumental in FC action. Intriguingly, 14‐3‐3 affected both channels in an opposite fashion: whereas K+in channel activity was fully dependent upon 14‐3‐3 proteins, K+out channel activity was reduced by 14‐3‐3 proteins by 60%. Together with previous data showing that 14‐3‐3 proteins control the activity of the plasma membrane H+‐ATPase, this makes 14‐3‐3 a prime candidate for molecular master regulator of the cellular osmo‐pump. Regulation of the osmo‐pump activity by ABA and FC is an important mechanism in controlling the growth of the embryonic root during seed germination.
Functional genomics uncovers three glucosyltransferases involved in the synthesis of the major sweet glucosides of Stevia rebaudiana
Authors: Richman Alex , Swanson Andrew , Humphrey Tania , Chapman Ralph , McGarvey Brian , Pocs Robert , Brandle Jim 
Published: December 2004

Summary Stevia rebaudiana leaves accumulate a mixture of at least eight different steviol glycosides. The pattern of glycosylation heavily influences the taste perception of these intensely sweet compounds. The majority of the glycosides are formed by four glucosylation reactions that start with steviol and end with rebaudioside A. The steps involve the addition of glucose to the C‐13 hydroxyl of steviol, the transfer of glucose to the C‐2′ and C‐3′ of the 13‐O‐glucose and the addition of glucose to the hydroxyl of the C‐4 carboxyl group. We used our collection of ESTs, an UDP‐glucosyltransferase (UGT)‐specific electronic probe and key word searches to identify candidate genes resident in our collection. Fifty‐four expressed sequence tags (ESTs) belonging to 17 clusters were found using this procedure. We isolated full length cDNAs for 12 of the UGTs, cloned them into an expression vector, and produced recombinant enzymes in Escherichia coli. An in vitro glucosyltransferase activity enzyme assay was conducted using quercetin, kaempferol, steviol, steviolmonoside, steviolbioside, and stevioside as sugar acceptors, and 14C‐UDP‐glucose as the donor. Thin layer chromatography was used to separate the products and three of the recombinant enzymes produced labelled products that co‐migrated with known standards. HPLC and LC‐ES/MS were then used to further define those reaction products. We determined that steviol UGTs behave in a regioselective manner and propose a modified pathway for the synthesis of rebaudioside A from steviol.
Identification of translocatable RNA‐binding phloem proteins from melon, potential components of the long‐distance RNA transport system
Authors: Gómez G. , Torres H. , Pallás V. 
Published: December 2004

SummaryPhloem proteins (P‐proteins) are an enigmatic group of proteins present in most angiosperm species. The best characterized P‐proteins (PP1 and PP2) are synthesized in companion cells, transported into sieve elements via pore plasmodesmata and translocated through the plant. Characteristics such as long‐distance translocation, RNA‐binding activity and capacity of increasing plasmodesmata exclusion size suggest that certain phloem proteins could be involved in RNA transport within the plant, forming translocatable ribonucleoprotein complexes with endogenous or pathogenic RNAs. Long‐distance movement of RNA through the phloem is a process known to occur, but both the mechanisms involved and the components constituting this potential information network remain unclear. Here, we demonstrate that several melon phloem proteins have a wide RNA‐binding activity. Serological assays strongly suggest that one of these proteins is the melon phloem protein 2 (CmmPP2). Mass spectrometry analysis undoubtedly identifies another one as the recently characterized melon phloem lectin (CmmLec17). Grafting experiments demonstrate that the CmmLec17 is a translocatable phloem protein, able to move through intergeneric grafts from melon to pumpkin. Translocatability and RNA‐binding activity was also demonstrated for an uncharacterized protein of approximately 14 kDa. In light of these results the possible involvement of these phloem proteins in the long‐distance transport of melon RNAs is discussed.
Membrane‐anchored prolyl hydroxylase with an export signal from the endoplasmic reticulum
Authors: Yuasa Koji , Toyooka Kiminori , Fukuda Hiroo , Matsuoka Ken 
Published: December 2004

SummaryWe cloned a novel prolyl 4‐hydroxylase (PH; EC 1.14.11.2) homolog cDNA from tobacco (Nicotiana tabacum) BY‐2 cells based on expression sequence tag information. Like other PHs, this tobacco PH polypeptide has two conserved histidine residues, and it comprises 286 amino acids with a calculated molecular mass of 32 kDa. Interestingly, this protein and homologs in Arabidopsis and rice have predicted transmembrane sequences in their N‐terminal regions. This PH homolog was expressed in BY‐2 cells as a His‐tagged protein, and the expressed protein showed PH activity. Incubation of membranes with high salt, urea, and protease with or without detergents indicated that this protein is an integral membrane protein with a type II configuration. Its membrane‐anchored nature is specific for plants because no integral membrane PH has been found in animals. A membrane fractionation study and immunocytochemical studies indicate that this protein localizes in both the endoplasmic reticulum (ER) and Golgi apparatus. Analysis of this protein fused to green fluorescent protein indicated that basic amino acids in the cytoplasmic, N‐terminal region of the PH play a role in its export from the ER.
Arabidopsis vacuolar H+‐ATPase subunit E isoform 1 is required for Golgi organization and vacuole function in embryogenesis
Authors: Strompen Georg , Dettmer Jan , Stierhof York‐Dieter , Schumacher Karin , Jürgens Gerd , Mayer Ulrike 
Published: December 2004

SummaryVacuolar H+‐ATPases play an important role in maintaining the pH of endomembrane compartments in eukaryotic cells. The functional relevance of this homeostasis for multicellular development has not been studied in plants. Here, we analyze the biological consequences resulting from the lack of subunit E isoform 1 (VHA‐E1) encoded by the Arabidopsis TUFF gene. tuff mutant embryos are lethal, displaying variably enlarged cells with multiple nuclei, large vacuoles containing inclusions, abnormal organization of Golgi stacks, and cell wall defects. Rescue of embryo lethality by cell cycle‐regulated expression of VHA‐E1 results in abnormal seedlings with non‐functional meristems and defective cell differentiation. VHA‐E1 is the predominant isoform in embryogenesis whereas VHA‐E3 is expressed mainly in the endosperm and surrounding maternal tissues during seed development, and VHA‐E2 is pollen‐specific. VHA‐E1 protein accumulates at endomembrane compartments including vacuoles and endosomes, but appears absent from the plasma membrane. Our results suggest an essential role for VHA‐E1 in maintaining a functional secretory system during somatic development but not in the haploid gametophytes.
β‐1,3‐Glucanase gene expression in low‐hydrated seeds as a mechanism for dormancy release during tobacco after‐ripening
Authors: Leubner‐Metzger Gerhard 
Published: December 2004

SummaryAn air‐dry developmental state with low‐hydrated tissues is a characteristic of most plant seeds. Seed dormancy is an intrinsic block of germination and can be released during after‐ripening, that is air‐dry storage of mature seeds. Both seed‐covering layers, testa and endosperm, cause the coat‐imposed dormancy of tobacco (Nicotiana tabacum). After‐ripening and over‐expression of class I β‐1,3‐glucanase (βGlu I) confer maternal effects on testa rupture and dormancy release. Very little is known about the molecular mechanisms of after‐ripening and whether gene expression is possible in low‐hydrated seeds. Transient, low‐level βGlu I transcription and translation was detected during tobacco seed after‐ripening. 1H NMR 2D micro‐imaging showed uneven distribution of proton mobility in seeds. βGlu I gene expression is associated spatially with the inner testa and temporally with the promotion of testa rupture. Local elevation in moisture content seems to permit local, low‐level βGlu I gene transcription and translation in the maternal tissues of air‐dry, low‐hydrated seeds. De novo gene expression is therefore proposed to be a novel molecular mechanism for the release of coat‐imposed dormancy during oilseed after‐ripening.
A new type of mutation in phytochrome A causes enhanced light sensitivity and alters the degradation and subcellular partitioning of the photoreceptor
Authors: Dieterle Monika , Bauer Diana , Büche Claudia , Krenz Martina , Schäfer Eberhard , Kretsch Thomas 
Published: December 2004

SummaryA specific light program consisting of multiple treatments with alternating red and far‐red light pulses was used to isolate mutants in phytochrome A‐dependent signal transduction pathways in Arabidopsis. Because of their phenotype, the mutants were called eid for empfindlicher im dunkelroten Licht, which means hypersensitive in far‐red light. One of the isolated mutants, eid4, is a novel semi‐dominant allele of the phytochrome A gene that carries a missense mutation in the chromophore‐binding domain. The mutation did not change the photochemical properties of the photoreceptor, but it leads to an increased stability under light conditions that induce its rapid degradation. Fusion proteins with the green fluorescent protein exhibited clear alterations in subcellular localization of the mutated photoreceptor: The fusion protein was impaired in the formation of sequestered areas of phytochrome in the cytosol, which can explain its reduced light‐dependent degradation. In contrast, the mutation stabilizes nuclear speckles (NUS) that appear late under continuous far‐red light, whereas the formation of early, transiently appearing NUS remained more or less unaltered.
Changes in lung function and tidal airflow patterns after increasing extrathoracic airway resistance
Authors: MORRIS M. Jocelyn , WILLIAMS E. Mark , MADGWICK Richard , BANERJEE Rajarshi , PHILLIPS Emma 
Published: December 2004

Objective:  The aim of this study was to determine what changes occur in previously described tidal expiratory flow patterns when extrathoracic resistance is added.Methodology:  A total of 16 subjects with normal lung function and 15 patients with chronic COPD, were studied. The following measurements were made before and after the addition of an extrathoracic expiratory resistance (EER; 0.89 kPa/L s at a flow of 0.5 L/s) during uncoached tidal breathing: expiratory time (tE), frequency (f), expiratory time to maximum flow/total expiratory time (tPTEF/tE), tidal maximum expiratory flow (PEFTIDAL), and time constant of the respiratory system calculated from the passive portion of tidal expiration (trsTIDAL). Post peak profiles were categorized as convex, linear or concave and time for flow to fall to 80% and 20% of maximum (t80 and t20) were measured.Results:  Tidal indices tE, f and PEFTIDAL, were similar in the two groups, but tPTEF/tE was greater and trsTIDAL was less in the normal subjects than in the COPD patients. Addition of EER in both groups caused PEFTIDAL to decrease and trsTIDAL, t80 and the percentage of convex profiles to increase. tPTEF/tE increased in the COPD patients but was unchanged in the control group.Conclusion:  After addition of EER during tidal breathing, expiratory flow in COPD patients resembled that seen in normal subjects.
Acute mountain sickness is associated with sleep desaturation at high altitude
Authors: BURGESS Keith R. , JOHNSON Pamela , EDWARDS Natalie , COOPER Jackie 
Published: December 2004

Objective:  This study was intended to demonstrate a biologically important association between acute mountain sickness (AMS) and sleep disordered breathing.Methodology:  A total of 14 subjects (eight males, six females aged 36 ± 10 years) were studied at six different altitudes from sea level to 5050 m over 12 days on a trekking route in the Nepal Himalaya. AMS was quantified by Lake Louise (LL) score. At each altitude, sleep was studied by 13 channel polysomnography (PSG). Resting arterial blood gases (ABG) and exercise SaO2 were measured. Ventilatory responses (VR) were measured at sea level. Individual data were analysed for association at several altitudes and mean data were analysed for association over all altitudes.Results:  ABG showed partial acclimatization. For the mean data, there were strong positive correlations between LL score and altitude, and periodic breathing, as expected. Strong negative correlations existed between LL score and PaO2, PaCO2, sleep SaO2 and exercise SaO2, but there was no correlation with sea level VR. There were equally tight correlations between LLs/PaO2 and LL score/sleep SaO2.The individual data showed no significant correlations with LL score at any altitude, probably reflecting the non‐steady state nature of the experiment. In addition, mean SaO2 during sleep was similar to minimum exercise SaO2 at each altitude and minimum sleep SaO2 was lower, suggesting that the hypoxic insult during sleep was equivalent to or greater than walking at high altitude.Conclusions:  It is concluded that desaturation during sleep has a biologically important association with AMS, and it is speculated that under similar conditions (trekking) it is an important cause of AMS.
COPD in Japan: the Nippon COPD Epidemiology study
Authors: FUKUCHI Yoshinosuke , NISHIMURA Masaharu , ICHINOSE Masakazu , ADACHI Mitsuru , NAGAI Atsushi , KURIYAMA Takayuki , TAKAHASHI Keiji , NISHIMURA Koichi , ISHIOKA Shinichi , AIZAWA Hisamichi , ZAHER Carol 
Published: December 2004

Objectives:  Despite high smoking rates, few prevalence studies of COPD have been performed in Asia. The Nippon COPD Epidemiology (NICE) Study used spirometry to measure prevalence of airflow limitation in Japanese adults.Methodology:  Clinical, spirometric, and risk factor exposure data were collected on 2343 subjects aged ≥ 40 years who were demographically similar to the Japanese population. Airflow limitation was defined according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria (FEV1/FVC < 70%).Results:  Prevalence of airflow limitation was 10.9%. Based upon GOLD severity criteria, 56% of these cases were found to be mild, 38% moderate, 5% severe, and 1% very severe. Airflow limitation was significantly more prevalent in males than females (16.4% vs. 5.0%; P < 0.001), in male ever‐smokers than female ever‐smokers (17.1% vs. 7.5%; P < 0.001), and in older subjects (3.5% in 40–49 years olds vs. 24.4% in those > 70 years; P < 0.001). Of note, airflow limitation was also found in 5.8% of non‐smokers and 4.6% of those younger than age 60 years. Only 9.4% of cases with airflow limitation reported a previous diagnosis of COPD.Conclusions:  Prevalence of airflow limitation in Japan is higher than previously reported, suggesting a high degree of under‐recognition of COPD. The high prevalence of smoking coupled with an aging population threatens to further increase the burden of COPD, highlighting the need for enhanced screening efforts and interventions of prevention and treatment.