Host effects in high ectomycorrhizal diversity tropical rainforests on ultramafic soils in New Caledonia

Tropical rainforests have been thought to have low prevalence and diversity of ectomycorrhizal symbioses. However, to date, tropical regions have been poorly sampled for ectomycorrhizal fungi. Here, we investigated ectomycorrhizal fungal community diversity and the role of host plants in shaping this diversity in three main ultramafic rainforests in New Caledonia, an archipelago renowned for its exceptional plant diversity and recognized as a biodiversity hotspot. Sampling of ectomycorrhizal root tips and fruit bodies in Nothofagus aequilateralis-dominated, Arillastrum gummiferum-dominated and mixed rainforests showed high fungal diversity with, in total, 28 lineages and 311 operational taxonomic units (OTUs), of which 95% might be endemic. We also found that host preference and host density influenced ectomycorrhizal community composition and contributed to the high fungal diversity of New Caledonian rainforests. Finally, the /cortinarius lineage dominated the below- and above-ground communities, which suggests that this lineage plays a central role in ultramafic ecosystems functioning.     

河南秃疮花属一新种及其核型

河南产秃疮花属一新种,河南秃疮花Dicranostigma henanensis S.Y.Wang et L.H.Wu.分析了该新种的核型,其核型公式为K(2n)=2x=12=6m (2SAT)+2sm+2st+2T。第一对染色体具随体,有时不明显。核型的不对称性为2B型。     

A Combination of Radiation and the Hypoxia-Activated Prodrug Evofosfamide (TH-302) is Efficacious against a Human Orthotopic Pancreatic Tumor Model

This study was designed to investigate the effect of single-dose radiation therapy (RT) in combination with evofosfamide (TH-302), a hypoxia-activated prodrug, in a pre-clinical model of pancreatic cancer. AsPC1 tumors were implanted orthotopically in the pancreas of nude mice. Tumors were treated with 15 Gy of RT, using a 1 cm diameter field, and delivered as a continuous arc. Image-guidance to center the field on the tumor was based on CT imaging with intraperitoneal contrast. Evofosfamide (100 mg/kg, i.p.) was administered 3 hours before RT. Tumor volumes were measured using ultrasound, and regrowth curves were plotted. Tumor hypoxia and cell proliferation were measured using pimonidazole and the thymidine analog EdU, respectively. In vitro clonogenic assays were performed. Tumors were shown to contain substantial areas of hypoxia, as calculated by percent pimonidazole staining. Evofosfamide was active in these tumors, as demonstrated by a significant reduction in uptake of the thymidine analog EdU. This effect was visible in oxygenated tissue, consistent with the previously reported bystander effects of evofosfamide. RT produced significant regrowth delay, as did evofosfamide. The combination of both agents produced a growth delay that was at least equal to the sum of the two treatments given separately. The improvement in tumor response when evofosfamide is combined with RT supports the hypothesis that hypoxia is a cause of radioresistance in high dose RT for pancreatic cancer. Assessing the efficacy and safety of stereotactic radiation treatment and evofosfamide is warranted in patients with locally advanced pancreatic cancer.     

Six New Species and One New Subspecies of Codonopsis(Campanulaceae) from the Pan Himalaya

Six species and one subspecies of Codonopsis are described from the Pan Himalaya as new in the present article. They are Codonopsis bomiensis, Ccampanulata, Celliptica, Chemisphaerica, Clixianica, Creflexa, and Ccardiophylla Diels ex Kom. subsp. megaphylla. The six new species each is provided with an illustration.     

2C DNA variation and relationships among New World species of the genus Lupinus (Fabaceae)

The 2C DNA values in 38 species and accessions of the genus Lupinus (Fabaceae) from the New World have been analysed using flow cytometry. They are representatives of North and South American species (the Atlantic and the Andean regions). Estimated 2C DNA values ranged from 1.08 pg in L. pusillus to 2.68 pg in L. albicaulis (both from North America), that is a variation of more than 2.5-fold. The variation for North American lupins was much higher than that for South American ones. Statistical analysis of the data resulted in a grouping that showed for North American lupins some correlation with the length of life cycle. Discussion concerns some aspects of the evolution of the genus.     

Riparian roots through time, space and disturbance

Riparian zones are landscape features adjacent to streams and are widely recognized as important in reducing erosion and filtering groundwater. Few studies directly investigate rooting dynamics of riparian areas, and little information exists concerning riparian root densities, biomass, depth profiles, changes through time, or vulnerability to disturbance. This study examined spatial and temporal patterns in root systems in streamsides influenced by season, hydrologic regime, vegetative composition, and ice storm disturbance in the eastern Adirondacks, New York. Sequential root cores and in-growth cores were collected from June 2000 through August 2001 in a riparian area with minimal ice storm damage adjacent to a third-order stream. Data were used to assess seasonal trends in root biomass and to provide a reference for spatial comparisons. The biomass and surface area of roots collected in the reference site cores were compared with cores collected at nine additional riparian sites differing in degree of canopy damage from the January 1998 ice storm. Average root biomass at the reference site was 1330 g/m², comparable to or greater than values reported for terrestrial and other riparian systems. Root biomass varied seasonally with a maximum root biomass in August, 2000; this result was not repeated the following year after the water table inundated much of the rooting zone in mid-June. Root biomass was spatially variable on a range of scales. Although the maximum root surface area occurred in the upper 10 cm, root biomass peaked at 20–30 cm belowground, unlike observations from most other root studies where the maximum root biomass has been found in the top 10 cm. Areas severely damaged by the ice storm had significantly less root biomass and surface area than areas with low damage. This study demonstrates that root biomass in riparian areas is highly dynamic over time, space, and across disturbance sites. Our findings suggest that the spatial variability in root densities has direct implications for riparian vulnerability to erosion.     

Hexasaturnalis nakasekoi nov. sp., a Jurassic saturnalid radiolarian species frequently confounded with Hexasaturnalis suboblongus (Yao)

Detailed morphological study of the ring of the Jurassic saturnalid radiolarian species frequently cited in the literature as Hexasaturnalis suboblongus (Yao) has proven that it contains two well-defined species: H. suboblongus (Yao), practically ranging within the boundaries of the Bajocian, and Hexasaturnalis nakasekoi nov. sp., ranging within the Bathonian-Kimmeridgian interval. The two species seem to be important stratigraphically because the transition from the former to the latter took place at or around the Bajocian/Bathonian boundary. The phyletic lineage Hexasaturnalis hexagonus (Yao) → H. inuyamaensis (Yao) → H. suboblongus (Yao) → H. nakasekoi nov. sp. → H. minor (Baumgartner) → Dicerosaturnalis angustus (Baumgartner) → D. dicranacanthos (Squinabol) is proposed.     

The teleomorph of Leptographium yunnanense, discovered in crosses among isolates from Thailand, China, and Japan

A teleomorph was discovered in crosses among isolates of Leptographium yunnanense isolated from Pinus spp. originating in Thailand, China, and Japan. The ascocarps are black, globose to subglobose, and lacking necks. Ascospores are hyaline, 1-celled, surrounded by hyaline sheaths, and appear cucullate in side view, quadrangular in face view, and triangular in end view. Three species were known to have teleomorphs morphologically similar to the present fungus. However, their anamorphs were distinguishable from L. yunnanense. Thus, this teleomorph is described as Grosmannia yunnanensis. Contribution No. 214, Laboratory of Plant Parasitic Mycology, Graduate School of Life & Environmental Sciences, University of Tsukuba.