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At least 901 records · Page 50Linked to original sources
PubMed2003

Mandibulotomy fixation: a laboratory analysis.

PURPOSE: Mandibulotomy is an access osteotomy technique associated with significant complications. Critical evaluation of available fixation systems is required to aid in the selection of the most stable fixation method. This study was designed to provide data on the stability of traditionally used plating configurations and a low-profile 2.0-mm locking plate (mandibular locking plate, Synthes MLP; Synthes Maxillofacial, Paoli, PA). MATERIALS AND METHODS: An in vitro red oak model was used to evaluate the stability provided by the study fixation devices. Five groups were studied as follows: group 1, two 4-hole 2.0-mm nonlocking miniplates; group 2, two 4-hole 2.0-mm mandibular locking plates; group 3, one 6-hole 2.0-mm mandibular locking plate; group 4, one 6-hole 2.4-mm nonlocking rigid plate; and group 5, control (uncut red oak blocks). Each specimen was tested with vertical loads applied over the osteotomy site. The force-versus-displacement behavior was recorded for each specimen and analyzed statistically. RESULTS: Plate type and configuration affected the resistance to vertical peak load (kilogram/force [kgf]) and the fixation stiffness (kgf/mm). The greatest peak load (58.92 kgf) and stiffness (7.07 kgf/mm) was found with group 2 specimens. The differences in system stiffness were statistically significant (P <.05), as were the peak loads for groups 1, 2, and 3. The control group (nonosteotomized red oak) had markedly higher values of peak load and stiffness (484 kg and 83 kg/mm, respectively). Group 2 specimens exhibited increased resistance to flexion. CONCLUSIONS: Two 2.0-mm locking plates provided the greatest resistance to vertical load.

Biomechanical Phenomena↗
PubMed2007

Gambel oak.

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Quercus↗
PubMed2005

Oaks.

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Pollen↗
PubMed2006

Penicillium glabrum cork-colonising isolates - preliminary analysis of their genomic similarity.

The cork stopper manufacturing process includes an operation, known as stabilisation, by which humid cork slabs are extensively colonised by fungi. The effects of fungal growth on cork are not completely understood although they are considered to be involved in the so-called "cork taint" of wine. It is essential to (a) identify environmental constraints which define the appearance of the colonising fungal species and (b) trace their origin to the forest and/or the manufacturing space. The present article correlates two sets of data, from consecutive years and the same season, of systematic sampling of two manufacturing units, located in the North and South of Portugal. Chrysonilia sitophila dominance was confirmed, followed by a high diversity of Penicillium species. Penicillium glabrum, which was found in all samples, was the most frequently isolated species. P. glabrum intra-species variability was investigated using DNA fingerprinting techniques revealing highly discriminative polymorphic markers in the genome. Cluster analysis of P. glabrum data was discussed in relation to the geographical location of strains, and results suggest that P. glabrum arise from predominantly the manufacturing space, although cork specific fungi can contribute.

Cluster Analysis↗
PubMed2006

Ambrosia fungi in the insect-fungi symbiosis in relation to cork oak decline.

Ambrosia fungi live associated with beetles (Scolytidae and Platypodidae) in host trees and act as a food source for the insects. The symbiotic relation is important to the colonizing strategies of host trees by beetles. Ambrosia fungi are dimorphic: they grow as ambrosial form and as mycelium. The fungi are highly specialized, adapted to a specific beetle and to the biotope where they both live. In addition other fungi have been found such as tree pathogenic fungi that may play a role in insects host colonization success. Saprophytic fungi are also present in insects galleries. These may decompose cellulose and/or be antagonistic to other less beneficial fungi. This paper summarizes the importance of ambrosia fungi and the interaction with insects and hosts. The possibility of the transport of pathogenic fungi by Platypus cylindrus to cork oak thus contributing for its decline is discussed.

Animal Structures↗
PubMed2001

Genealogical inference of closely related species based on microsatellites.

Despite their unmatched popularity in many research areas, microsatellites have not yet become a major tool for the inference of genealogical relationships of closely related species. Recent studies have successfully extended the repertoire of microsatellite analysis beyond population genetics and demonstrate that phylogenetic relationships of closely related species can be inferred accurately with fewer loci than previously assumed.

Animals↗
PubMed2003

Phenotypic plasticity and evolutionary potential in somatic cells of Armillaria gallica.

Somatic cells of Armillaria gallica fruit bodies have been shown to possess different genotypes for molecular-marker and mating-type loci. Here we report experiments on six quantitative traits and demonstrate that somatic cells of fruit bodies possess almost as much genetic variation for growth rate and phenotypic plasticity as do spores, the products of meiosis. Genetically distinct somatic cells therefore have the potential to grow at different rates relative to one another during primordial fruit body formation. This may confer an advantage on all cell lines within a fruit body, not just those that happen to grow better under a particular set of conditions. To our knowledge, genetic variation for fitness-related traits that make up a single genetic individual has not been reported before.

Adaptation, Physiological↗
PubMed2003

Responses of the root rot fungus Collybia fusipes to soil waterlogging and oxygen availability.

Collybia fusipes is a common root rot fungus in mature pedunculate oak forest, that causes drastic destruction of the tree root systems, especially in dry or mildly waterlogged soils. We wanted to check, under controlled conditions or in forest ecosystems, whether reduced O2 during saturation of the soil by water could interact with disease evolution. Susceptibility of waterlogged oak seedlings to C. fusipes was tested in a greenhouse and the survival of the pathogen in woody substrates was assessed in hydromorphic soils in a forest. A direct and detrimental effect of soil waterlogging on C. fusipes survival was evidenced both under controlled conditions and in forest stands. Growth of C. fusipes mycelium on agar media was monitored under low O2 mole fraction and compared to that of Armillaria mellea and Heterobasidion annosum. A drastic reduction in mycelial growth was evidenced in C. fusipes and H. annosum but not in A. mellea.

Agaricales↗
PubMed2003

Phylogenetic relationships of Phytophthora ramorum, P. nemorosa, and P. pseudosyringae, three species recovered from areas in California with sudden oak death.

Sudden oak death has been an emerging disease problem in coastal California and has caused significant losses in forest ecosystems in some regions of the state. The causal agent of this disease has been described as Phytophthora ramorum with two other less aggressive species, P. nemorosa and P. pseudosyringae, recovered from some symptomatic plants. The phylogenetic relationship of these species with other members of the genus was examined by sequence alignment of 667 bp of the mitochondrially-encoded cytochrome oxidase II gene and the nuclear encoded rDNA internal transcribed spacer region. P. ramorum was most closely related to P. hibernalis and P. lateralis in trees from both regions, although the specific relationship among species differed depending on the tree. In the cox II tree these species were on a single clade with P. lateralis basal to a group containing P. ramorum and P. hibernalis. On the maximum parsimony ITS tree P. ramorum was most closely affiliated with P. lateralis and in the same clade as P. hibernalis, but with maximum likelihood analysis P. ramorum was basal to a grouping of P. hibernalis and P. lateralis. While bootstrap support was strong for the grouping of these species together, it was not for determining the relationship among them. In contrast to the cox II tree, the clade containing these three species grouped with P. cryptogea, P. drechsleri, P. erythroseptica, and P. syringae in the ITS tree. Since the same isolates of these species were used for both the cox II and ITS sequence analysis, this difference in species grouping suggests either a differential rate of evolutionary divergence for these two regions, incorrect assumptions about alignment of ITS sequences, or different evolutionary histories of the regions under study. Analysis of combined cox II and ITS data sets gave trees where the relationships among these species were the same as for the ITS tree alone, although the results of the partition homogeneity test (P=0.072) suggest caution should be used in interpretation of this data. All analyses supported a close relationship between P. ilicis, P. nemorosa and P. pseudosyringae, although the analysis did not clarify the evolutionary relationships among these three species. Interestingly, these three species had a unique 6 bp deletion in the cox II gene just before the termination codon. While there was some similarity in phylogenetic grouping of these species and morphological characteristics, this was not consistent across all comparisons in the genus. Data would suggest that P. ramorum, P. nemorosa and P. pseudosyringae are phylogenetically distinct new species and not the result of interspecific hybridization.

Base Sequence↗
PubMed2004

Growth and interspecific interactions of the rare oak polypore Piptoporus quercinus.

Growth and interactions of Piptoporus quercinus were studied in artificial culture to give insights into the ecological characteristics of a species which is both rare and widespread. P. quercinus grew slowly under all conditions, the maximum ranging between 1.9 and 3.15 mm d(-1), depending on isolate, at 25 degrees C pH 3.75. Upper limits for growth were 25-30 degrees or above 30 degrees depending on isolate, and pH 6.6. Lower limits for growth were 5-10 degrees, between -1.75 and -2.5 MPa; there was still growth at pH 1.81. Preincubating plates at 5 for 77 d and then incubating at 20 degrees resulted in a significantly greater extension rate (2.89 mm d(-1)) than when incubated continuously at 20 degrees (1.70 mm d(-1)) for one isolate though not for another isolate. P. quercinus survived exposure to low temperature (-18 degrees for 7 d), showing renewed growth, albeit limited, after a lag of 37 d. It was a poor combatant, being unable to replace any of the eight fungi (with a range of ecological roles) against which it was paired, and being replaced or partially replaced by most, on 2% MA at pH 5.49, at pH 3.75 and at -1.25 MPa. It did, however, inhibit extension rate of some other heart rot fungi. Results are discussed in an ecological context.

Colony Count, Microbial↗
PubMed2004

Production of gametangia by Phytophthora ramorum in vitro.

Until now gametangia have not been obtained between paired European A1 and American A2 isolates of Phytopthora ramorum in vitro. Their production in artificial culture relies on interspecific pairings. Using P. drechsleri and P. cambivora testers, 51 of 110 P. ramorum isolates from across Europe were all shown to be A1s; while 32 of 38 American isolates from across California and southwest Oregon were shown to be A2s. However, these interspecific pairings are complex, unusually slow and unpredictable. A range of culture media and conditions are described that were tested, unsuccessfully, with a view to enhancing the efficiency of the interspecific pairings. In further tests, gametangia were obtained between A1 and A2 isolates of P. ramorum when juvenile, pre-chlamydospore producing mycelia were mixed together on carrot agar. The gametangia formed in 3-10 d, sparsely to frequently, initially only within the boundaries of the mixed inocula but subsequently in the extended mycelial growth. Chlamydospores were also produced. This inoculum-mixing method, though again sometimes unpredictable, should enhance efficiency of testing for compatibility types and facilitate further studies on whether the sexual outcrossing system of P. ramorum is functional. Differences between sexual reproduction of P. ramorum and that of other heterothallic Phytophthora species are discussed.

Crosses, Genetic↗
PubMed2005

Fungal diversity during initial stages of leaf decomposition in a stream.

Maple, linden and oak leaves were immersed in a stream for 1-21 d. Cumulative mass loss, ergosterol content, and species richness of released aquatic hyphomycete conidia increased with time. Numbers and richness of attached conidia were highest on days 1 and 2. Denaturing gradient gel electrophoresis revealed up to seven fungal phylotypes on the leaves before their immersion in the stream and after one day of stream exposure. After 5 d of immersion the contribution of these terrestrial fungi decreased and that of aquatic hyphomycetes increased. The dominant phylotypes belonged to Anguillispora filiformis, Articulospora tetracladia and Flagellospora curvula, which also dominated the community of released spores. The molecular diversity was highest on day 2 and 3 on all substrates. This may be due to a few species of terrestrial fungi, later outcompeted by aquatic hyphomycetes, and to many different conidia of aquatic hyphomycetes, some of which may germinate but are unable to establish themselves and reproduce.

Acer↗
PubMed2004

AFLP and phylogenetic analyses of North American and European populations of Phytophthora ramorum.

The genetic structure within and between USA and European populations of the emerging phytopathogen Phytophthora ramorum was examined. Four primer combinations were used for amplified fragment length polymorphism (AFLP) fingerprinting of 67 USA isolates from California and Oregon, and 18 European isolates from Belgium, Germany, The Netherlands, Spain and the UK. In addition, three DNA regions (ITS, cox II, and nad 5) of additional Phytophthora species were amplified by polymerase chain reaction, sequenced, and analysed to provide better phylogenetic understanding of P. ramorum within the genus Phytophthora. AFLP banding patterns indicate that the 85 isolates form two distinct lineages within a monophyletic group, distinct from the closely related outgroup species P. lateralis. With the exception of two isolates from an Oregon nursery, European and USA isolates clustered separately within individual clades. The AFLP profiles also indicate that a single clonal lineage dominates the North American population, while the European population consists of an array of mainly unique, closely related AFLP types. Sequences from the three DNA regions were identical among all P. ramorum isolates, and phylogenetic analysis indicates that P. ramorum is closely related to P. lateralis and P. hibernalis.

Base Sequence↗
PubMed2005

New PCR assay detects rare tooth fungi in wood where traditional approaches fail.

Lu et al. (2002) described a method for identifying Hericium species by PCR, using the primers HT-U1 and HT-L1 which they specifically designed for this purpose. In our hands these primers do not appear to discriminate between tooth fungi and other wood decay species. Therefore PCR primers were designed that discriminated Creolophus cirrhatus from other species (HER2F/HER3R), and which discriminate Hericium alpestre, H. coralloides and H. erinaceus from other wood decay Ascomycota and Basidiomycota but not from each other (HER2F/HER2R). Using the HER2F/HER3R primers together with traditional isolation and direct incubation procedures, the location of C. cirrhatus in Turkey oak logs was mapped. The PCR approach often detected C. cirrhatus in locations where it was suspected to be, based on patterns of staining and decay, but where it was not revealed by isolation onto agar media, emphasising the value of adopting several approaches to unravel fungal community structure in wood.

Basidiomycota↗
PubMed2005

Ophiostoma dentifundum sp. nov. from oak in Europe, characterized using molecular phylogenetic data and morphology.

Previous phylogenetic studies based on ITS sequence data have shown that Ophiostoma species with Sporothrix anamorphs include several species complexes. Isolates from oak in Poland and Hungary, which have previously been referred to as O. stenoceras, as well as isolates morphologically similar to S. inflata formed the basis of this study. Identification was based on sequences for the ITS region of rDNA operon and partial beta-tubulin gene. Analyses showed that isolates from Poland and Hungary reside in a well resolved clade, separate from those in the O. stenoceras-complex. The morphology of these isolates was compared with those of strains in the O. stenoceras complex and S. inflata. Morphological differences in teleomorph and anamorph structures were found between the isolates from Poland and Hungary and those in the O. stenoceras-complex. Growth characteristics and the presence of the teleomorph in culture could be used to separate this fungus from isolates in the S. inflata-complex. The fungus from Poland and Hungary is described here as O. dentifundum sp. nov. It is phylogenetically most closely related to isolates of S. inflata, which represent four well defined groups based on morphology and DNA sequence phylogeny.

Ascomycota↗