A new species of <Emphasis Type="Italic">Cosmospora</Emphasis> and the first record of sexual state of <Emphasis Type="Italic">C. lavitskiae</Emphasis>

A new fungicolous species, Cosmospora inonoticola, is described and illustrated based on a specimen collected from northeast China. It is characterized by the occurrence of fruitbodies of Inonotus sp.; perithecia nonstromatic, subglobose to pyriform, not collapsing when dry; clavate asci containing (3–)6(?8) spores; ascospores ellipsoidal to broadly ellipsoidal, pale brown, finely warted, bicellular, conspicuously constricted at septum; and producing a verticillium-like asexual state. A multi-locus analysis of the combined ITS, rpb1 and tub sequences confirmed its taxonomic position, and revealed the distinction from its morphologically similar species including the type species, C. coccinea, which occurs also on Inonotus. A specimen with sexual state of C. lavitskiae is reported for the first time, and a reference specimen is indicated.     

An unusual <Emphasis Type="Italic">Lophodermium</Emphasis> species on needles of <Emphasis Type="Italic">Pinus taiwanensis</Emphasis> from China

An interesting fungus, which appeared to resemble a contaminated or infected Lophodermium species, is described and illustrated in this paper. The circinate apex of paraphyses, which intertwined with each other, and the broad slit exposing the unusual-white hymenium distinguished the new species from other known Lophodermium species. Evidence from two markers including internal transcribed spacer (ITS) region and the partial Actin gene indicated that L. pini-taiwanensis was in a robust and separate clade. It is, therefore, described as a new Lophodermium species.     

Isolation and molecular characterization of the fungal endophytic microbiome from conventionally and organically grown avocado trees in South Florida

Fungal endophytes are the most ubiquitous and highly diverse microorganisms that inhabit the interior of healthy plants. They are important in plant ecology and offer untapped potential to improve plant health and productivity in agroecosystems. The endophytic assemblage of avocado is poorly understood; therefore, surveys of fungal endophytes of Persea americana Mill. (Avocado) in South Florida organic and conventional orchards were conducted. A total of 17 endophytic fungal species were recovered from healthy avocado terminal branches. Endophytic fungal species were identified by rDNA sequencing of the internal transcribed spacer (ITS) region, using UNITE Species Hypotheses to reliably assign a taxon name, and determined as belonging to the genera Alternaria, Cladosporium, Colletotrichum, Corynespora, Diaporthe, Lasiodiplodia, Neofusicoccum, Neopestalotiopsis, Phyllosticta, and Strelitziana. Endophyte community assemblage differed between organic and conventional agroecosystems. This is the first report of Alternaria eichhorniae, Cladosporium tenuissimum, Corynespora cassiicola, Colletotrichum alatae, Diaporthe fraxini-angustifoliae, Lasiodiplodia gonubiensis, Neofusicoccum algeriense, Neofusicoccum andinum, Neopestalotiopsis foedans, Phyllosticta capitalensis, and Strelitziana africana as endophytes of avocado. Evaluation using pathogenicity tests on avocado leaves and terminal branches showed that endophytic fungal isolates did not cause disease symptoms.     

Taxonomic and phylogenetic placement of <Emphasis Type="Italic">Nodulosphaeria</Emphasis>

Nodulosphaeria is a ubiquitous genus that comprises saprobic, endophytic and pathogenic species associated with a wide variety of substrates and has 64 species epithets listed in Index Fungorum. The classification of species in the genus has been a major challenge due to a lack of understanding of the importance of characters used to distinguish taxa, as well as the lack of reference strains. The present study clarifies the phylogenetic placement of the genus and related species, using fresh collections from Italy. Four Nodulosphaeria species are characterized based on multi-loci analyses of ITS, LSU, SSU, TEF and RPB2 sequence datasets. Phylogenetic analyses indicate that Nodulosphaeria species group within the family Phaeosphaeriaceae as a distinct genus. The sexual morphs of Nodulosphaeria hirta and N. spectabilis are described and illustrated using modern concepts. Two new Nodulosphaeria species are introduced. The phylogenetic relationships and taxonomy of the genus Nodulosphaeria are discussed, but further sampling with fresh collections, reference or ex-type strains and molecular data are needed to obtain a better and natural classification for the genus.     

New species and reports of <Emphasis Type="Italic">Hypoxylon</Emphasis> from Argentina recognized by a polyphasic approach

A preliminary account of Hypoxylon species (Xylariaceae) from the hitherto widely unexplored “Yungas” mountain forests of Northwest Argentina is presented. Two new species are described based on extensive morphological, molecular (ITS region of rDNA, partial β-tubulin gene) and chemotaxonomic data. Hypoxylon spegazzinianum is close to H. erythrostroma, but differs by larger ascospores and a virgariella-like asexual morph. Hypoxylon calileguense resembles H. subgilvum when growing on wood, but can be distinguished by larger ascospores and a fawn to brick stromatal surface colour. Stromata found on bark have affinities to H. pelliculosum, but differ in their stromatal surface colour and conspicuous amyloid apical apparatus. In addition, nine taxa of Hypoxylon are reported for Argentina for the first time, and some details on their asexual state and stromatal secondary metabolites are reported. An updated dichotomous key for Hypoxylon species from Argentina is provided.     

The influence and biomechanical role of cartilage split line pattern on tibiofemoral cartilage stress distribution during the stance phase of gait

This study presents an evaluation of the role that cartilage fibre ‘split line’ orientation plays in informing femoral cartilage stress patterns. A two-stage model is presented consisting of a whole knee joint coupled to a tissue-level cartilage model for computational efficiency. The whole joint model may be easily customised to any MRI or CT geometry using free-form deformation. Three ‘split line’ patterns (medial–lateral, anterior–posterior and random) were implemented in a finite element model with constitutive properties referring to this ‘split line’ orientation as a finite element fibre field. The medial–lateral orientation was similar to anatomy and was derived from imaging studies. Model predictions showed that ‘split lines’ are formed along the line of maximum principal strains and may have a biomechanical role of protecting the cartilage by limiting the cartilage deformation to the area of higher cartilage thickness.     

Effects of aortic irregularities on blood flow

Anatomic aortic anomalies are seen in many medical conditions and are known to cause disturbances in blood flow. Turner syndrome (TS) is a genetic disorder occurring only in females where cardiovascular anomalies, particularly of the aorta, are frequently encountered. In this study, numerical simulations are applied to investigate the flow characteristics in four TS patient- related aortic arches (a normal geometry, dilatation, coarctation and elongation of the transverse aorta). The Quemada viscosity model was applied to account for the non-Newtonian behavior of blood. The blood is treated as a mixture consisting of water and red blood cells (RBC) where the RBCs are modeled as a convected scalar. The results show clear geometry effects where the flow structures and RBC distribution are significantly different between the aortas. Transitional flow is observed as a jet is formed due to a constriction in the descending aorta for the coarctation case. RBC dilution is found to vary between the aortas, influencing the WSS. Moreover, the local variations in RBC volume fraction may induce large viscosity variations, stressing the importance of accounting for the non-Newtonian effects.     

Model of cellular mechanotransduction via actin stress fibers

Mechanical stresses due to blood flow regulate vascular endothelial cell structure and function and play a key role in arterial physiology and pathology. In particular, the development of atherosclerosis has been shown to correlate with regions of disturbed blood flow where endothelial cells are round and have a randomly organized cytoskeleton. Thus, deciphering the relation between the mechanical environment, cell structure, and cell function is a key step toward understanding the early development of atherosclerosis. Recent experiments have demonstrated very rapid (\(\sim \)100 ms) and long-distance (\(\sim \)10 \(\upmu \)m) cellular mechanotransduction in which prestressed actin stress fibers play a critical role. Here, we develop a model of mechanical signal transmission within a cell by describing strains in a network of prestressed viscoelastic stress fibers following the application of a force to the cell surface. We find force transmission dynamics that are consistent with experimental results. We also show that the extent of stress fiber alignment and the direction of the applied force relative to this alignment are key determinants of the efficiency of mechanical signal transmission. These results are consistent with the link observed experimentally between cytoskeletal organization, mechanical stress, and cellular responsiveness to stress. Based on these results, we suggest that mechanical strain of actin stress fibers under force constitutes a key link in the mechanotransduction chain.