bluuebunny/crossref_metadata_2025_split huggingface dataset:
The phloem, a miracle of ingenuity
Authors: VAN BEL A. J. E. 
Published: March 2003

ABSTRACTThis review deals with aspects of the cellular and molecular biology of the sieve element/companion cell complex, the functional unit of sieve tubes in angiosperms. It includes the following issues: (a) evolution of the sieve elements; (b) the specific structural outfit of sieve elements and its functional significance; (c) modes of cellular and molecular interaction between sieve element and companion cell; (d) plasmodesmal trafficking between sieve element and companion cell as the basis for macromolecular long‐distance signalling in the phloem; (e) diversity of sieve element/companion cell complexes in the respective phloem zones (collection phloem, transport phloem, release phloem); (f) deployment of carriers, pumps and channels on the plasma membrane of sieve element/companion cell complexes in various phloem zones; and (g) implications of the molecular‐cellular equipment of sieve element/companion cells complexes for mass flow of water and solutes in a whole‐plant frame.
Genetic diversity in the mango malformation pathogen and development of a PCR assay
Authors: Zheng Q. , Ploetz R. 
Published: March 2003

Malformation is a destructive disease of mango, Mangifera indica. Its causal agent possesses the morphological features of Fusarium subglutinans, a species whose taxonomy and nomenclature has recently been in a state of flux. Genetic diversity was examined among 74 F. subglutinans‐like isolates from malformed mango in Brazil, Egypt, Florida (USA), India, Israel and South Africa. With nitrate‐nonutilizing (nit) auxotrophic mutants, seven vegetative compatibility groups (VCGs) were identified. Three of the VCGs were found in a single country, and VCG diversity was greatest in Egypt and the USA where, respectively, four and three different VCGs were found. RAPD profiles generated with arbitrary decamer primers were variable among isolates in different VCGs, but were generally uniform for isolates within a VCG. In PCR assays, a 20‐mer primer pair that was developed previously to identify F. subglutinans from maize (mating population [MP]‐E of the Gibberella fujikuroi complex) also amplified a specific 448 bp fragment for isolates of F. sacchari from sugarcane (MP‐B) and what was probably F. circinatum (pine, MP‐H). With the exception of three isolates from Brazil, it did not amplify the fragment from F. subglutinans‐like isolates from mango. A second pair of 20‐mer primers was developed from a unique fragment in the RAPD assays. It amplified a specific 608 bp fragment for 51 of 54 isolates from mango (all but the three Brazilian isolates). It also amplified a smaller, 550 bp fragment from isolates of F. nygamai (MP‐G), but did not amplify DNA of isolates of any other taxon of Fusarium that was tested.
Effects of root‐ and stolon‐infecting fungi on root‐colonizing nematodes of white clover
Authors: Zahid M. I. , Gurr G. M. , Nikandrow A. , Hodda M. , Fulkerson W. J. , Nicol H. I. 
Published: March 2003

The effects on white clover (Trifolium repens) of different combinations of the nematodes Meloidogyne trifoliophila, Helicotylenchus dihystera and Heterodera trifolii and nine stolon‐infecting and three root‐infecting fungi were studied in a glasshouse experiment. The presence of the fungus Phytophthora megasperma alone increased (P < 0·001) root‐rot severity and reduced (P < 0·001) plant growth. Other species combinations, such as Phoma nebulosa and Alternaria alternata, interacted and increased root‐rot severity. Combinations of P. megasperma with Pythium irregulare, and P. nebulosa with Phoma medicaginis or A. alternata, increased M. trifoliophila populations. Several other fungi (P. irregulare, P. nebulosa, Colletotrichum coccodes, Macrophomina phaseolina, P. medicaginis and Phoma sp.) interacted with the nematode M. trifoliophila causing severe root‐knot symptoms. The results indicated that fungi and nematodes interacted to cause root and stolon rot and reduced yields, and that poor persistence of white clover in pastures is likely to be a problem with a complex etiology.
Botryosphaeria canker of Cistus ladanifer
Authors: Sánchez‐Hernández M. E. , Gutiérrez‐García J. , Trapero‐Casas A. 
Published: March 2003

The shrub Cistus ladanifer (gum cistus, rock rose) is a key component of the Maquis in the Mediterranean forests of southern Spain and Portugal. Between 1996 and 1998, and coinciding with exceptionally high rainfall rates, a disease characterized by foliar wilting and death of branches, leading to death of the whole plant, affected C. ladanifer in the Mediterranean oak and pine forests in Andalucía (southern Spain). Field surveys carried out in 15 forest areas showed that diseased branches were associated with the presence of strips of necrotic bark. Botryosphaeria dothidea was consistently obtained from the necrotic tissues. Growth of isolates on potato dextrose agar was very rapid at high temperatures, with a growth rate of 25 mm day−1 at the optimum temperature (about 28°C). Germination rate of conidia increased with temperature, with the optimum temperature being over 35°C. Pathogenicity tests were conducted on cut branches, 3‐year‐old seedlings and mature plants in the field. In every situation, disease symptoms were reproduced in the inoculated branches and Koch’s postulates were fulfilled. The results demonstrate the behaviour of B. dothidea as a primary pathogen of C. ladanifer. The present work constitutes the first description of fungal canker of C. ladanifer caused by B. dothidea, being the first report of a disease affecting this shrub species.
Evaluation of potential biocontrol agents against Claviceps africana in vitro and in vivo
Authors: Bhuiyan S. A. , Ryley M. J. , Galea V. J. , Tay D. 
Published: March 2003

Undiluted culture filtrates of two commercial products of Trichoderma spp., Trichopel and Trichoflow, and two isolates of Penicillium citrinum completely inhibited the conidial germination of macroconidia of Claviceps africana, the cause of ergot or sugary disease of sorghum (Sorghum bicolor) in vitro. Similarly, Pseudomonas aeruginosa and Burkholderia cepacia completely inhibited macroconidial germination, with the former being more effective at high dilutions. In contrast, these bacterial isolates failed to inhibit infection in vivo in glasshouse tests with ergot‐inoculated sorghum, but all fungal biocontrol agents (including an isolate of Epicoccum nigrum) reduced the severity of disease (percentage of infected spikelets per panicle), in some cases completely inhibiting the development of ergot. In a second glasshouse trial, optimum control was achieved when the biocontrol agents were applied 3–7 days before inoculation with conidia of C. africana.
Anti‐Inflammatory Activities of Human Lactoferrin in Acute Dextran Sulphate‐Induced Colitis in Mice
Authors: Håversen L. A. , Baltzer L. , Dolphin G. , Hanson L. Å. , Mattsby‐Baltzer I. 
Published: March 2003

AbstractIn this study, we investigated the anti‐inflammatory effects of orally administered human lactoferrin (hLF) and two peptides, based on the bactericidal region of hLF (HLD1 and HLD2), on the course of experimental colitis. Acute colitis was induced in C57Bl/6 mice by giving 5% dextran sulphate (DX) in the drinking water. The mice were killed after 2 or 7 days of DX exposure. The animals were given hLF or the peptides orally twice a day (2 mg/dose/mouse) during the DX exposure. In the control animals, the hLF or the peptides were replaced by bovine serum albumin or water.The appearance of occult blood in the faeces and macroscopic rectal bleeding were significantly delayed and partly reduced in the hLF‐treated animals compared with the control animals. The shortening of the colon, a pathological effect of DX exposure, was significantly less pronounced in the hLF‐treated group compared with the control group. Also, the interleukin‐1β (IL‐1β) levels in the blood were significantly diminished in this group after 2 days of DX exposure. A significantly lower crypt score was observed in the distal part of the colon in the hLF‐treated group compared with the control group. Also, significantly reduced numbers of CD4 cells, F4/80‐positive macrophages and tumour necrosis factor‐α‐producing cells were detected by immunohistochemistry in the distal colon of the hLF‐treated animals compared with the control animals after 7 days of DX exposure. A reduction was also observed concerning the IL‐10‐producing cells in the middle colonic submucosa. The HLD1 and HLD2 treatment, which was carried out for 2 days, only gave results almost identical to those of hLF, concerning clinical parameters after the 2 days of DX exposure. An even stronger effect was observed for HLD2, regarding decreased occult blood in the faeces and colon length.Our results show that perorally given hLF mediates anti‐inflammatory effects on the DX‐induced acute colitis, and further suggest that the bactericidal region of the hLF molecule may be involved in these activities.
Effects of Various Adjuvants and a Viral Infection on the Antibody Specificity Toward Native or Cryptic Epitopes of a Protein Antigen
Authors: Gómez K. A. , Longhi S. A. , Marino V. J. , Mathieu P. A. , Loureiro M. E. , Coutelier J.‐P. , Roguin L. P. , Retegui L. A. 
Published: March 2003

AbstractAn immunization protocol that induces antibodies (Abs) directed to cryptic epitopes of a protein antigen (Ag) reduces the efficacy of vaccines that ideally should induce Abs against native epitopes. We have shown earlier that viral infections concomitant with immunization against a protein tend to shift the Ab specificity toward cryptic epitopes and tend to induce the production of autoantibodies (autoAbs). Here, we show the effects of three adjuvants on the Ab specificity in the absence or presence of a viral infection (lactate dehydrogenase‐elevating virus or LDV), with human growth hormone (hGH) being, as before, the protein Ag.Pathogen‐free CBA/Ht and BALB/c mice were immunized with hGH in the presence of complete Freund's adjuvant (CFA), monophosphoryl lipid A (MPL) or alum, with the animals being either infected with LDV or not infected with LDV. Conventional and competition enzyme‐linked immunosorbent assays (ELISAs) indicated that in noninfected mice, CFA induced higher titres of anti‐hGH Ab than did MPL or alum, with the Ab being almost totally directed to cryptic hGH epitopes. Strikingly, CFA plus LDV infection in CBA/Ht mice shifted the specificity of the anti‐hGH Ab toward native epitopes, whereas the virus decreased the Ab titre when MPL or alum was used. Our Western blot results showed that 70% of mice immunized with hGH in the presence of any adjuvant produced autoAbs against a variety of tissue Ags. The amount of autoAb and the concentration of Ab to hGH cryptic epitopes did correlate, suggesting a relationship between both kinds of Ab. Significant differences were observed in the various effects of adjuvants and the viral infection between the two mouse strains used in this work.
Indoleamine 2,3‐Dioxygenase Expression in Patients with Acute Graft‐versus‐Host Disease after Allogeneic Stem Cell Transplantation and in Pregnant Women: Association with the Induction of Allogeneic Immune Tolerance?
Authors: Steckel N. K. , Kuhn U. , Beelen D. W. , Elmaagacli A. H. 
Published: March 2003

AbstractIndoleamine 2,3‐dioxygenase (IDO) is an interferon‐γ (IFN‐γ)‐induced enzyme, which is suggested to play an important role in the prevention of allogeneic fetal rejection. IDO effects the suppression of T‐cell activity by catabolizing the essential amino acid l‐tryptophan. We studied IDO expression by reverse transcription polymerase chain reaction (RT‐PCR) in dendritic cells and by real‐time RT‐PCR in monocytes of patients undergoing allogeneic transplantation for leukaemia, who developed acute graft‐versus‐host disease (aGvHD), and compared the IDO expression with that of pregnant women and healthy volunteers.A spontaneous IDO expression was detected in the monocytes of 20 pregnant women with an IDO/glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) ratio at a median of 1.0%, whereas none of 15 healthy volunteers or patients after allogeneic transplant had any detectable spontaneous IDO expression. The IDO expression increased by in vitro IFN‐γ stimulation in pregnant women (median 116%), healthy volunteers (median 11.7%) and patients with a low‐grade aGvHD (grades 0–II) 28 days after transplant (median 433%) but not in patients with a severe aGvHD (grades III–IV) (median 0%), which was highly significant (P < 0.01).IDO expression was also measured in dendritic cells by qualitative RT‐PCR, where a spontaneous IDO expression was detected in 16 of 31 (52%) pregnant women versus none of 17 healthy volunteers and none of 62 studied patients after transplant. IFN‐γ‐induced IDO expression was detected in all pregnant women, all volunteers and 47 of 49 (96%) patients with a low‐grade aGvHD (grades 0–II) after transplant, whereas only in two of 13 (16%) patients with aGvHD grade III–IV was IFN‐γ‐induced IDO expression observed.These data suggest that IDO expression might be involved in the development of allogeneic immune tolerance.
Hot‐spring travertine facies and sequences, Late Pleistocene, Rapolano Terme, Italy
Authors: Guo Li , Riding Robert 
Published: March 2003

Late Pleistocene travertines up to 40 m thick near Rapolano Terme in Tuscany, central Italy, were precipitated by hot water issuing from springs on hillsides and flowing into adjacent depressions to mix with rainwater. Proximal light‐coloured slope and terrace travertines pass distally into darker reed mound and depression‐fill travertines. Lithotypes include crystalline crust, shrub, pisoid, paper‐thin raft, coated bubble, reed, and lithoclast‐breccia. High precipitation rates resulted in rapid slope aggradation and progradation. Dilution by rainwater likely lowered precipitation rates in depressions, but deposition was augmented by allochthonous material eroded from upslope travertines.Slope Depositional Systems consist of Smooth and Terrace Slope facies characterized by white crystalline crusts, with diverse additional lithotypes in terrace pools. Depression Depositional Systems have mixed light and dark travertines with horizontal to gently concave stratification. Extensive light‐coloured Shrub Flat travertine is dominant; darker Marsh‐Pool Facies composed of fine lithoclast and reed travertine is localized. Reed Mounds composed of mixed light and dark travertines localized by abundant reed growth, formed where spring water emerged near the bases of low angle slopes.Distal reduction in accretion rate was the major influence on sequence development. Light‐coloured slope travertines interdigitate with darker depression deposits. Vertical aggradation of slope deposits, mound progradation, and filling of topographic depressions is expressed by advance and retreat of facies. Evolution from depression to slope or mound sequences is termed ‘steepening up’. Up‐sequence change from slope or mound to depression facies is termed ‘levelling up’. Exposure surfaces associated with palaeosols are common in all facies and often constitute sequence boundaries. They are more closely spaced in depression sequences, reflecting slower and possibly also more discontinuous accumulation at sites furthest from hot springs.
Radar facies of paraglacial barrier systems: coastal New England, USA
Authors: Heteren Sytze Van , Fitzgerald Duncan M. , Mckinlay Paul A. , Buynevich Ilya V. 
Published: March 2003

Analysis of a large data base of ground‐penetrating‐radar (GPR) profiles from both natural and developed paraglacial barriers along the coast of New England has allowed identification of eight reflection configurations that characterize this type of mid‐ to high‐latitude coastal environment. Bedrock anchor points yield primarily hyperbolic configurations, whereas glacial anchor points and sediment‐source areas are characterized by chaotic, parallel, and tangential‐oblique configurations. Beaches and dunes produce predominantly sigmoidal oblique, hummocky, reflection‐free, and bounding‐surface configurations. Back‐barrier sediments may yield basin‐fill configurations, but generally include abundant signal‐attenuating units.The GPR data, calibrated with information from cores, were collected across swash‐aligned and drift‐aligned barriers in a variety of wave‐ and tidal‐energy settings. Application of a 120‐MHz antenna, as used in this study, enables portrayal of a range of sedimentary units, from individual bedforms (on single records) to entire barrier elements (using large numbers of intersecting GPR sections), at maximum vertical resolutions that vary between 0·2 m and 0·7 m.The most important drawback of GPR in the coastal environment is attenuation of the electromagnetic (EM) signal by layers of salt‐marsh peat or by brackish or salty groundwater, primarily along barrier edges. This disadvantage is offset by many benefits. Data can be collected at rates of several km per day, making GPR an excellent reconnaissance tool. A core that is used in the calibration of GPR data can be matched with great accuracy to its position on the complementary GPR record, allowing detailed correlation between lithostratigraphy and reflection configuration.
Archean cherts derived from chemical, biogenic and clastic sedimentation in a shallow restricted basin: examples from the Gorge Creek Group in the Pilbara Block
Authors: SUGITANI K. , YAMAMOTO K. , ADACHI M. , KAWABE I. , SUGISAKI R. 
Published: March 2003

The >3·0 Ga chert sequence of the Gorge Creek Group is exposed at Ord Ranges about 50 km east of Port Hedland in the Pilbara Block. The chert sequence examined in this study is 15 m thick and consists of oxide‐rich laminated chert, grey chert (silicified clastic rock), carbonaceous black chert and carbonate‐rich laminated chert. Although the cherts have undergone postdepositional silica enrichment, such as cementation and metasomatic silicification, primary precipitation of silica at the site of deposition is indicated by abundant microstructures (mosaic and spherulitic structures). Other primary to early diagenetic components were carbonates, sulphates (gypsum and anhydrite) and organic matter. Although these mineral associations, on the whole, correspond to those of modern marine evaporites, they are different from modern equivalents with respect to abundant precipitation of amorphous silica and presumed primary precipitation of iron‐carbonate (siderite). This feature is a possible manifestation of peculiar physicochemical conditions in the water mass from which the chemical sediments were precipitated; compared with modern ocean waters, the concentrations of Fe and Si were significantly higher and the pH value might have been lower. These conditions could be obtained by contributions of Fe‐ and Si‐enriched hydrothermal solutions and continental run‐off to the site of deposition.Grey cherts contain detrital quartz and altered Fe–Ti oxides and were formed in a period of input of terrigenous detrital materials. They are characterized by higher concentrations of TiO2, Al2O3, Cr, Ni, Zn, Rb and Zr compared with the other types of chert and by very low (< 4) Al2O3/TiO2 values. These features are attributed to the supply of terrigenous detrital materials that contain abundant Fe–Ti oxides (ilmenite and titanomagnetite) and fine TiO2 particles. Such detrital materials might have been formed by extensive chemical alteration of source rocks and residual enrichment of Ti relative to Al.
Dynamics of the turbidity maximum zone in a micro‐tidal estuary: Hawkesbury River, Australia
Authors: Hughes  , Harris  , Hubble  
Published: March 2003

Bed sediment, velocity and turbidity data are presented from a large (145 km long), generally well‐mixed, micro‐tidal estuary in south‐eastern Australia. The percentage of mud in the bed sediments reaches a maximum in a relatively narrow zone centred ≈30–40 km from the estuary mouth. Regular tidal resuspension of these bed sediments produces a turbidity maximum (TM) zone in the same location. The maximum recorded depth‐averaged turbidity was 90 FTU and the maximum near‐bed turbidity was 228 FTU. These values correspond to suspended particulate matter (SPM) concentrations of roughly 86 and 219 mg l−1, respectively.Neither of the two existing theories that describe the development and location of the TM zone in the extensively studied meso‐ and macro‐tidal estuaries of northern Europe (namely, gravitational circulation and tidal asymmetry) provide a complete explanation for the location of the TM zone in the Hawkesbury River. Two important factors distinguish the Hawkesbury from these other estuaries: (1) the fresh water discharge rate and supply of sediment to the estuary head is very low for most of the time, and (2) suspension concentrations derived from tidal stirring of the bed sediments are comparatively low. The first factor means that sediment delivery to the estuary is largely restricted to short‐lived, large‐magnitude, fluvial flood events. During these events the estuary becomes partially mixed and it is hypothesized that the resulting gravitational circulation focuses mud deposition at the flood‐determined salt intrusion limit (some 35 km seaward of the typical salt intrusion limit). The second factor means that easily entrained high concentration suspensions (or fluid muds), typical of meso‐ and macro‐tidal estuaries, are absent. Maintenance of the TM zone during low‐flow periods is due to an erosion‐lag process, together with a local divergence in tidal velocity residuals, which prevent the TM zone from becoming diffused along the estuary axis.
Intertidal clay‐drape couplets (Gironde estuary, France)
Authors: Fenies Hugues , Resseguier Amaury De , Tastet Jean‐Pierre 
Published: March 2003

Clay‐drape couplets on subaqueous dunes have been regarded as a diagnostic feature of the subtidal environment since Visser’s seminal paper (1980). The new observation of clay‐drape couplets in the intertidal zone on a present day tidal bar of the Gironde estuary shows that they are not restricted to the subtidal zone.In the intertidal zone, low‐tide slack‐water clay drapes are deposited in the bottomsets of the dominant current dunes when the muddy water retained in the troughs is absorbed into the sand during the emergence of the intertidal bar. They drape emergence run‐off ripples generated by the drainage currents in the bottomsets. High‐tide slack‐water clay drapes are deposited over the entire dune surface and are preserved on the lee side of the dunes and in the bottomsets. They drape the subordinate current ripples. Low‐tide and high‐tide slack‐water clay drapes enclose one thin rippled sand layer (the subordinate current bundle) and are isolated from other adjacent clay‐drape couplets by the dominant current bundle.The clay‐drape couplets deposited in the intertidal zone can be distinguished from their subtidal counterparts on the basis of two morphological differences:1. In the intertidal zone, the low‐tide clay drape is only present in the bottomsets of the dunes, whereas in the subtidal zone equivalent clay drapes are also present on the lower part of the lee side of the dunes.2. In the intertidal zone, low‐tide clay drapes are deposited in the bottomsets of the dunes over emergence run‐off ripples oriented in the direction of the drainage currents (i.e. in a direction normal to the tidal currents). Conversely, in the subtidal zone, the equivalent clay drapes are typically deposited over ripples oriented in the tidal‐current direction (ebb or flood). There is a difference of polarity of 90° between the intertidal and subtidal small‐scale bedforms draped by the low‐tide slack‐water drapes.