bluuebunny/crossref_metadata_2025_split huggingface dataset:
Top‐down and bottom‐up regulation of herbivores: Spodoptera frugiperda turns tables on endophyte‐mediated plant defence and virulence of an entomopathogenic nematode
Authors: Richmond Douglas S. , Kunkel Brian A. , Somasekhar Nethi , Grewal Parwinder S. 
Published: May 2004

Abstract.  1. The fungus Neotyphodium lolii forms a symbiotic relationship with its grass host Lolium perenne (perennial ryegrass). The fungus benefits from access to plant nutrients and photosynthate, whereas the plant benefits from acquired chemical defence against herbivory.2. This study examined the potential for endophyte‐mediated plant defences to influence interactions between fall armyworm Spodoptera frugiperda, and the entomopathogenic nematode Steinernema carpocapsae and clarified biological mechanisms underlying the observations made.3. In laboratory and greenhouse experiments, S. frugiperda larvae were fed endophytic or non‐endophytic L. perenne then exposed to S. carpocapsae or injected with the nematodes' symbiotic bacteria Xenorhabdus nematophila.4. In all instances, S. frugiperda larvae fed endophyte‐infected grass suffered significantly lower mortality than those fed non‐endophytic plants. Although larvae fed endophyte‐infected grass often had significantly lower biomass than those fed uninfected grass, these differences did not account for altered susceptibility to S. carpocapsae.5. Endophyte‐mediated reductions in herbivore susceptibility to the nematode pathogen represent a herbivore adaptation that effectively turns the tables on both plant and natural enemy by reducing the virulence of the nematodes' symbiotic bacteria while expanding the temporal window of herbivory.
Calcium measurement in living filamentous fungi expressing codon‐optimized aequorin
Authors: Nelson G. , Kozlova‐Zwinderman O. , Collis A. J. , Knight M. R. , Fincham J. R. S. , Stanger C. P. , Renwick A. , Hessing J. G. M. , Punt P. J. , Van Den Hondel C. A. M. J. J. , Read N. D. 
Published: May 2004

SummaryCalcium signalling is little understood in filamentous fungi largely because easy and routine methods for calcium measurement in living hyphae have previously been unavailable. We have developed the recombinant aequorin method for this purpose. High levels of aequorin expression were obtained in Neurospora crassa, Aspergillus niger and Aspergillus awamori by codon optimization of the aequorin gene. Three external stimuli (mechanical perturbation, hypo‐osmotic shock and high external calcium) were found transiently to increase [Ca2+]c. Each of the calcium signatures associated with these physico‐chemical treatments was unique, suggesting the involvement of three distinct calcium‐mediated signal transduction pathways. The fungal calcium channel blocker KP4 inhibited the [Ca2+]c responses to hypo‐osmotic shock and high external calcium, but not to mechanical perturbation. The divalent cation chelator BAPTA inhibited [Ca2+]c responses to mechanical perturbation and hypo‐osmotic shock. The calcium agonists A23187 and cyclopiazonic acid increased [Ca2+]c levels.
The RING‐finger domain of the fungal repressor crgA is essential for accurate light regulation of carotenogenesis
Authors: Lorca‐Pascual Juan M. , Murcia‐Flores Laura , Garre Victoriano , Torres‐Martínez Santiago , Ruiz‐Vázquez Rosa M. 
Published: May 2004

Summary Mucor circinelloides responds to blue light by activating the biosynthesis of carotenoids. Gene crgA acts as a repressor of this light‐regulated process, as its inactivation leads to overaccumulation of carotenoids in both the dark and the light. The predicted CrgA protein contains different recognizable structural domains, including a RING‐finger zinc‐binding motif, several glutamine‐rich regions, a putative nuclear localization signal and an isoprenylation domain. To gain insight into the specific mode of action of the CrgA protein, we sought to define the CrgA domains critical for the light regulation of carotenogenesis. For this, mutant crgA alleles harbouring missense or deletion mutations in conserved residues of those domains were generated, and their functionality was assessed by testing their ability to complement a null crgA mutation. Point mutations of the amino‐terminal RING‐finger domain abrogated the ability of CrgA to repress carotenogenesis in the dark, as did the deletion of a poly glutamine‐rich region at the carboxyl domain of CrgA. In contrast, mutations of the isoprenylation domain only slightly affected the CrgA function in carotenogenesis. The results identify two functional domains presumably involved in protein–protein interaction in the CrgA protein and suggest a role for the ubiquitin–proteasome pathway in the light regulation of carotenogenesis in fungi.
The FNR‐type transcriptional regulator SinR controls maturation of Agrobacterium tumefaciens biofilms
Authors: Ramey Bronwyn E. , Matthysse Ann G. , Fuqua Clay 
Published: May 2004

Summary Agrobacterium tumefaciens is a plant pathogen that persists as surface‐associated populations on plants or soil particles. A genetic screen for A. tumefaciens mutants deficient for surface interactions identified a mutant that forms thin, sparsely populated biofilms, but is proficient for initial attachment. The mutant is disrupted in a gene designated sinR, encoding a member of the DNR subfamily of FNR‐type transcription regulators. SinR is required for normal maturation of A. tumefaciens biofilms on both inert surfaces and plant tissues, and elevated sinR expression results in accelerated biofilm formation. Expression of sinR is increased close to 30‐fold in cultures grown in oxygen‐limited environments and is also induced within biofilms grown under oxic conditions. A consensus FNR box, the presumptive binding site for FNR‐type proteins, is located upstream of the sinR promoter. FnrN, a second A. tumefaciens FNR‐like regulator, is required for induction of sinR in oxygen‐limited cultures, whereas SinR negatively influences its own expression. FnrN influences biofilm formation, but its effects are less dramatic than those of SinR. We propose a model in which a signal cascade, responsive to oxygen limitation and initiated by FnrN, activates sinR expression in response to decreased oxygen levels, and influences the formation of A. tumefaciens biofilms.
Upper Carboniferous to Lower Permian volcanic successions of the Carroll–Nandewar region, northern Tamworth Belt, southern New England Orogen, Australia*
Authors: ROBERTS J. , OFFLER R. , FANNING M. 
Published: May 2004

Geological mapping in the Carroll–Nandewar region near the northwestern margin of the Tamworth Belt has identified an Upper Carboniferous to Lower Permian succession, the Willuri Formation, containing coarse volcaniclastic sediments and interbedded dacitic to rhyolitic pyroclastics, lavas and a possible dome or coulée. The Currangandi Group (new) accommodates Upper Carboniferous volcaniclastic formations in the northern Tamworth Belt, including the Willuri Formation. Volcanic rocks in the Willuri Formation are distributed in four stratigraphically distinct, intertonguing or overlapping packages: the Kaputar, Piney Range, Tulcumba and Gunnan packages. According to SHRIMP (AS3) dating most of the succession ranges in age from ca 320 to ca 308 Ma (Namurian–Westphalian). Dacitic and rhyolitic lavas, apparently in sequence with the succession on the northwestern part of Tulcumba Ridge, are 297–287 Ma or younger (Early Permian). They appear to disconformably overlie the Carboniferous succession and could be either part of the Willuri Formation or related to the Boggabri Volcanics. Volcanic centres near Maules Creek (Kaputar centre) and Wean (Wean centre) appear to have been the sources for volcanics in the Kaputar package and most parts of the Rocky Creek region to the northeast, and the Tulcumba and probably the Piney Range packages, respectively. In the Gunnan package a single major ignimbrite was derived from a volcanic centre in the Werrie pyroclastic field, but the provenance of other pyroclastics is unknown. Correlations based on SHRIMP ages and the distribution of pyroclastics indicate that the Willuri Formation is equivalent to most of the Currabubula Formation in the Werrie Syncline, and to the Rocky Creek Conglomerate and Lark Hill Formation in the Rocky Creek region. Boundaries of the Werrie and Rocky Creek pyroclastic fields are adjusted to incorporate a new pyroclastic field based on the Wean volcanic centre and covering the Tulcumba and Piney Range packages of the Willuri Formation.
Sedimentology and geochemistry of an urban coastal lake system: Coombabah Lake Nature Reserve, Gold Coast, Queensland
Authors: FRANK T. D. , FIELDING C. R. 
Published: May 2004

A study was initiated to address environmental concerns associated with changes in land use in the catchment area of Coombabah Lake, a brackish coastal lake system located in southeast Queensland. Sedimentological and geochemical data derived from a series of cores that penetrate the ca. 0–6000 year‐old lacustrine sequence indicate that throughout much of its history, Coombabah Lake has remained a quiet, shallow, water body fed by fine‐grained sediment dropped from suspension. Discrete and laterally continuous, shelly horizons form the basis for the stratigraphy developed for the lake sequence. A lithological transition in the upper 50 cm of the sediment column, from mud to shell‐rich, sandy mud, suggests that the depositional regime changed ∼500 years ago as accommodation space was filled. At this time, the dominant sedimentary processes changed to include reworking, partial bypass of sediment, the intermittent concentration of shell debris by winnowing, and the development of a flood‐tidal delta complex in the lower reaches of the lake. Sharp increases in total organic carbon, total nitrogen, and total phosphorus concentrations below the lithological transition at 50 cm depth suggest that the capacity of the system to preserve organic matter and trap nutrients decreased significantly after the transition in depositional regime. Results indicate that current conditions in Lake Coombabah are governed by natural processes associated with the long‐term evolution of coastal lake systems, and reveal little to suggest that there were any adverse affects resulting from recent human activities in the surrounding catchment.
Alunite alteration of tuffaceous layers and zircon dating, Upper Permian Kennedy Group, Carnarvon Basin, Western Australia
Authors: LEVER H. , FANNING C. M. 
Published: May 2004

Alunite layers were found in two locations in the Binthalya Formation, Upper Kennedy Group, of Late Permian age, in the Merlinleigh Sub‐basin, onshore Carnarvon Basin. Alunite has not previously been reported from the Kennedy Group, or from a similar setting in Western Australia. The alunite occurs in discrete layers that have different chemical signatures to surrounding, unaltered sedimentary rocks. The lack of alteration in surrounding sedimentary rocks suggests that alteration was localised by initial differences in lithology, rather than by fortuitous localisation of alteration in a single layer. Alunite is thought to be the product of alteration of K‐feldspars, clay minerals and pyrite under acidic, specifically sulfuric, conditions. It is found in hydrothermal systems and weathering profiles. Because the precursor minerals of alunite are believed to be feldspars, clays and sulfur‐rich minerals, tuffaceous layers are the probable precursors of the alunite layers. Sulfur for the reaction was derived from within the tuffaceous deposits or from the oxidation of pyrite, which was probably present as cementation of trace fossils in other beds. The alteration is thought to have occurred during extensive oxidation, weathering and laterite formation during the Cenozoic, because the low density and powdery nature of the alunite indicates that it developed at a shallow depth. U–Pb dates obtained from zircons extracted from the alunite layers returned ages ranging from ca 2690 Ma to ca 270 Ma. The majority of zircons are inherited from the same source as the Kennedy Group sediments, indicating mixing of the initial tuffaceous layers with background sedimentation, either during the sedimentation process or afterwards by reworking or biological disturbance.
Development of Type 2 fold interference patterns in the Broken Hill Block: implications for strain partitioning across a detachment during the Olarian Orogeny
Authors: FORBES C. J. , BETTS P. G. 
Published: May 2004

A north–south‐trending relatively high‐strain shear zone active during the earliest stages of the ca 1.60–1.58 Ga Olarian Orogeny bounds domains characterised by different structural geometries in the northern Broken Hill Block. To the west of the shear zone Freyers Metasediments preserve Type 2 'mushroom' fold interference patterns between fold generations F2 and F3. Recumbent F2 folds are highly non‐cylindrical. These were subsequently overprinted by north‐orientated close to tight upright folds (F3). To the east of the shear zone, in the Parnell Formation, F2 folds are not developed and the structural grain reflects the F3 folding event. The shear zone is interpreted to represent a local detachment that accommodated lateral transportation of hangingwall rocks, producing non‐cylindrical recumbent folding during thin‐skinned deformation (D2). F3 folds represent thick‐skinned deformation during the late stages of the Olarian Orogeny, folding rocks above and below the detachment. This resulted in zones of different structural geometry and strain pattern across the detachment.
Evidence of Late Cenozoic uplift and climate change in the stratigraphy of the Macquarie River valley, New South Wales
Authors: TOMKINS K. M. , HESSE P. P. 
Published: May 2004

The stratigraphy of the alluvial sediments filling the Macquarie River valley, New South Wales, was investigated to test models of landscape evolution of the rifted margin Eastern Highlands of Australia. In the neighbouring Lachlan River valley, the stratigraphy of Neogene sediments has been incorporated into a model proposing denudation and episodic passive (denudational isostatic) uplift of the highlands throughout the Neogene. In this study, we aimed to test the regional extent of this model and the influence of sediment supply on the stratigraphic record and its interpretation. The sediments of the Macquarie River valley show three major changes in the depositional regime. First, erosion of the valley basement in the Late Miocene was followed by (and possibly synchronous with) deposition of a basal clay and sand unit in the Late Miocene. Second, the valley was filled with a wedge of sediment containing abundant gravel and sand in the Pliocene; and third, the older gravelly unit was eroded and reworked in the Quaternary, and a sandy clay unit, which forms the modern floodplain, was deposited. Deformation of the Middle Miocene basalt‐filled valley provides good evidence for substantial uplift of the highlands in the Middle–Late Miocene, synchronous with or shortly after widespread volcanism, but continuing no later than the Late Miocene. The Pleistocene incision is best accounted for by climate change to drier conditions, triggering a sediment‐starved response by the Macquarie River, rather than further uplift. While valley incision and subsequent infilling can be viewed as a response to tectonism, the internal sedimentology and stratigraphy of the sediments appears to respond to fluctuations in sediment supply brought about by extrinsic climate change and intrinsic catchment lithology. The first‐order tectonic events are not synchronous with uplift in the Lachlan valley and are restricted to relatively local spatial scales. However, the secondary climatic forcing has a broader regional expression.
The Biomechanical Effects of Low-Dose Irradiation on Bone-Patellar Tendon-Bone Allografts
Authors: Curran Andrew R. , Adams Douglas J. , Gill Julie L. , Steiner Mark E. , Scheller Arnold D. 
Published: May 2004

Background Despite evidence that low-dose irradiation of 2 Mrad (20 kGy) is not virucidal for patellar tendon allografts and reduces tissue strength, many tissue bank protocols include low-dose irradiation. Hypothesis Maintaining tissue mechanical integrity may be particularly relevant toward accelerated rehabilitation of the injured knee, where the cyclic function of patellar tendon allografts is critical. Study Design Controlled laboratory study. Methods The cyclic and failure mechanical properties of paired bone-patellar tendon-bone allografts, with and without current low-dose irradiation of 20 kGy, were evaluated. Specimens were loaded from 50 N to 250 N for 1000 cycles at 0.5 Hz and subsequently loaded to failure at a strain rate of 100% per second. Results After 1000 cycles, grafts elongated 27% more when irradiated than when not (4.4 ± 1.5 mm vs 3.4 ± 1.0 mm; P = .03). Failure load averaged 1965 ± 512 N for irradiated grafts and 2457 ± 647 N for nonirradiated grafts (P = .007). Conclusions The diminished strength of irradiated grafts may contribute to overt anterior cruciate ligament graft failure, and the increase in cyclic elongation may also be detrimental to graft function. Clinical Relevance These results suggest that one should consider the use of nonirradiated allografts as an alternative to irradiated grafts in anterior cruciate ligament reconstruction.
Results of Transphyseal Anterior Cruciate Ligament Reconstruction Using Patellar Tendon Autograft in Tanner Stage 3 or 4 Adolescents with Clearly Open Growth Plates
Authors: Shelbourne K. Donald , Gray Tinker , Wiley Bryan V. 
Published: May 2004

Background Drilling across the physes for intra-articular anterior cruciate ligament reconstruction is considered risky for skeletally immature patients. Hypothesis Skeletally immature patients with clearly open growth plates can safely undergo intra-articular anterior cruciate ligament reconstruction with patellar tendon autograft without suffering growth plate disturbance. Study Design Retrospective review of prospectively collected data. Methods Surgery involved drilling tunnels through the tibial and femoral physes, the bone plugs were placed proximal to the physes, and button fixation was placed on the cortex. Of 272 skeletally immature patients, 16 had clearly open growth plates. Tanner stage of physical development was evaluated. Follow-up evaluation included objective and subjective data. Results At the time of surgery, 7 patients were Tanner stage 3 and 9 were Tanner stage 4. Clinical follow-up (mean, 3.4 years after surgery) showed that the mean growth after surgery was 11.7 ± 4.2 cm for boys and 6.6 ± 2.3 cm for girls. No patients had growth plate disturbances, gross leg deformities, or gross leg-length discrepancies. Subjective results (mean, 5.6 years after surgery) showed a mean total score of 97.6 ± 2.9 for the modified Noyes survey and 95.4 ± 6.9 for the International Knee Documentation Committee survey. All patients returned to competitive sports after surgery. Conclusion In 16 skeletally immature patients with clearly open growth plates who were Tanner stage 3 or 4, an intra-articular anterior cruciate ligament reconstruction was performed using a patellar tendon autograft with no gross growth disturbance; however, the surgical technique was meticulous for placing the bone plugs proximal to the physes, and the graft was not overtensioned.
Primary Repair of Posterior Cruciate Ligament Avulsion Fracture
Authors: Inoue Masayuki , Yasuda Kazunori , Kondo Eiji , Saito Katsutoshi , Ishibe Motomi 
Published: May 2004

Background In the posterior cruciate ligament avulsion fracture, posterior instability cannot be completely restored by the anatomical reduction and fixation of an avulsed fragment. Hypothesis The occult midsubstance injury inside the posterior cruciate ligament may affect the residual posterior instability after anatomical reduction and internal fixation of the avulsed fragment. Study Design Prospective comparative clinical study. Methods Thirty-one patients were followed for a period of 2 to 8 years. Based on magnetic resonance images taken immediately after the injury, these patients were divided into 2 groups, the occult injury group (group O, 15 knees) and the uninjured group (group N, 16 knees). Results The side-to-side difference of the posterior knee instability was 3.2 mm in group O and 3.0 mm in group N. Approximately 60% of the knees examined showed mild posterior instability in both groups. There were no significant differences found between the 2 groups. Conclusion The occult posterior cruciate ligament midsubstance injury does not significantly affect postoperative posterior instability of the knee. This fact did not support the hypothesis that has been commonly considered thus far. Clinical Relevance It is not necessary for orthopaedic surgeons to be overly apprehensive about occult midsubstance injury in the treatment of posterior cruciate ligament avulsion fracture.
Active Patellar Tracking Measurement
Authors: Shih Yi-Fen , Bull Anthony M.J. , McGregor Alison H. , Amis Andrew A. 
Published: May 2004

Background Many patients suffer patellar instability that may relate to transient patellar tracking abnormalities. Objective To develop and test a technique to measure dynamic patellar tracking. Study Design Controlled laboratory and in vivo study. Method A functional knee brace was modified to allow an ultrasound transducer to be mounted laterally to the femur, following the path of the patella during knee movement. An ultrasound system was used to measure patellar mediolateral position parallel to the femoral transepicondylar axis. Ten subjects with no patellar instability were studied to obtain patellar tracking and accuracy data. Results The interobserver and intraobserver reproducibility ranged from 0.2 ± 0.1 mm to 1.0 ± 0.5 mm. The accuracy of the ultrasound measurement was checked against magnetic resonance imaging and was 0.6 ± 1.9 mm. The patella moved medially then laterally from extension to flexion when sitting. Squatting and stepping produced a more lateral path, without the initial medial translation. The patella was more lateral during knee extension than during flexion. Conclusions This novel method for measurement of dynamic patellar mediolateral tracking was found to have good intraobserver and interobserver reproducibility, and the measurements matched closely with those obtained from magnetic resonance imaging reconstructions of static patellar positions. Some preliminary data for tracking in 3 activities were obtained from 10 normal knees.
HTLV-I Tax induces a novel interaction between p65/RelA and p53 that results in inhibition of p53 transcriptional activity
Authors: Jeong Soo-Jin , Radonovich Michael , Brady John N. , Pise-Masison Cynthia A. 
Published: May 2004

AbstractNuclear factor κB (NF-κB) activation plays a critical role in oncogenesis by human T-cell lymphotrophic virus type I (HTLV-I), the etiologic agent of adult T-cell leukemia (ATL), and is indispensable for maintenance of the malignant phenotype. In T lymphocytes, Tax-mediated p53 inhibition is dependent on Tax activation of the NF-κB pathway and is linked to p53 phosphorylation. We now report that blocking NF-κB transcriptional activation in HTLV-I–transformed cells restores p53 activity. Further, using mouse embryo fibroblast (MEF) null cells and antisense oligonucleotides to inhibit expression of NF-κB family members, we demonstrate that the p65 subunit of NF-κB is uniquely involved in p53 inhibition. Coimmunoprecipitation assays demonstrate an interaction between p65 and p53 in HTLV-I–transformed cells. In transient transfection assays, we demonstrate that Tax induces the p53-p65 interaction. Phosphorylation of p53 at serines 15 and 392 is critical for complex formation. Importantly, Tax-mediated p53 inhibition correlates with p65 and p53 interaction. By using chromatin immunoprecipitation (ChIP) assays, we find that in HTLV-I–transformed cells p53 and p65 form a complex on the inactive, p53-responsive murine double minute 2 (MDM2) promoter. Consistent with reduced transcriptional activity, transcription factor IID (TFIID) binding is not observed. These studies identify a unique mechanism for p53 regulation by the p65/RelA subunit of NF-κB.