Arbuscular mycorrhizal (AM) fungi are biotrophic symbionts colonizing about two-thirds of land plant species and found in all ecosystems. They are of major importance in plant nutrient supply and their diversity is suggested to be an important determinant of plant community composition. The diversity of the AM fungal community composition in the roots of two plant species (Agrostis capillaris and Trifolium repens) that co-occurred in the same grassland ecosystem was characterized using molecular techniques. We analysed the small subunit (SSU) ribosomal RNA gene amplified from a total root DNA extract using AM fungal-specific primers. A total of 2001 cloned fragments from 47 root samples obtained on four dates were analysed by restriction fragment length polymorphism, and 121 of them were sequenced. The diversity found was high: a total of 24 different phylotypes (groups of phylogenetically related sequences) colonized the roots of the two host species. Phylogenetic analyses demonstrate that 19 of these phylotypes belonged to the Glomaceae, three to the Acaulosporaceae and two to the Gigasporaceae. Our study reveals clearly that the AM fungal community colonizing T. repens differed from that colonizing A. capillaris, providing evidence for AM fungal host preference. In addition, our results reveal dynamic changes in the AM fungal community through time.

Arbuscular mycorrhizal (AM) fungi are biotrophic symbionts colonizing the majority of land plants, and are of major importance in plant nutrient supply. Their diversity is suggested to be an important determinant of plant community structure, but the influence of host-plant and environmental factors on AM fungal community in plant roots is poorly documented. Using the terminal restriction fragment length polymorphism (T-RFLP) strategy, the diversity of AM fungi was assessed in 89 roots of three grass species (Agrostis capillaris, Festuca rubra, Poa pratensis) that co-occurred in the same plots of a field experiment. The impact of different soil amendments (nitrogen, lime, nitrogen and lime) and insecticide application on AM fungal community was also studied. The level of diversity found in AM fungal communities using the T-RFLP strategy was consistent with previous studies based on clone libraries. Our results clearly confirm that an AM fungal host-plant preference exists, even between different grass species. AM communities colonizing A. capillaris were statistically different from the others (P < 0.05). Although grass species evenness changed in amended soils, AM fungal community composition in roots of a given grass species remained stable. Conversely, in plots where insecticide was applied, we found higher AM fungal diversity and, in F. rubra roots, a statistically different AM fungal community.

Background: Delivery of the vesicle into the pre-fusion state during tethering is not understood. Results: Interactions between the COG complex, golgins and Rabs were mapped. Two ends of the golgin TMF both bind COG and different Rabs, the middle binds the target membrane. Conclusion: COG may reel the vesicle into docking along the golgin. Significance: Mechanistic link between tethering complex and coiled tether established.

There is an unmet need for circulating biomarkers that can detect early-stage lung cancer. Here we show that a variant form of the nuclear matrix-associated DNA replication factor Ciz1 is present in 34/35 lung tumors but not in adjacent tissue, giving rise to stable protein quantifiable by Western blot in less than a microliter of plasma from lung cancer patients. In two independent sets, with 170 and 160 samples, respectively, variant Ciz1 correctly identified patients who had stage 1 lung cancer with clinically useful accuracy. For set 1, mean variant Ciz1 level in individuals without diagnosed tumors established a threshold that correctly classified 98% of small cell lung cancers (SCLC) and non-SCLC patients [receiver operator characteristic area under the curve (AUC) 0.958]. Within set 2, comparison of patients with stage 1 non-SCLC with asymptomatic age-matched smokers or individuals with benign lung nodules correctly classified 95% of patients (AUCs 0.913 and 0.905), with overall specificity of 76% and 71%, respectively. Moreover, using the mean of controls in set 1, we achieved 95% sensitivity among patients with stage 1 non-SCLC patients in set 2 with 74% specificity, demonstrating the robustness of the classification. RNAimediated selective depletion of variant Ciz1 is sufficient to restrain the growth of tumor cells that express it, identifying variant Ciz1 as a functionally relevant driver of cell proliferation in vitro and in vivo. The data show that variant Ciz1 is a strong candidate for a cancer-specific single marker capable of identifying early-stage lung cancer within at-risk groups without resort to invasive procedures.

The arbuscular mycorrhizal (AM) fungi have been elevated to the phylum Glomeromycota based on a ribosomal gene phylogeny. In order to test this phylogeny, we amplified and sequenced small subunit ribosomal RNA (SSUrRNA), actin and elongation factor 1 (EF1)-alpha gene fragments from single spores of Acaulospora laevis, Glomus caledonium, Gigaspora margarita, and Scutellospora dipurpurescens. Sequence variation within and among spores of an isolate was low except for SSUrRNA in S. dipurpurescens, and the actin amino acid sequence was more conserved than that of EF1-alpha. The AM fungal sequences were more similar to one another than to any other fungal group. Joint phylogenetic analysis of the actin and EF1-alpha sequences suggested that the sister group to the AM fungi was a Zygomycete order, the Mortierellales.

The DNA replication protein Ciz1 promotes initiation of mammalian DNA replication in cooperation with cyclin A-dependent kinase, most likely by delivering cyclin A to sites where cyclin E-dependent pre-replication complex assembly has taken place. Normally, Ciz1 is anchored within nuclear matrix-associated foci that co-localize with sites of DNA replication, but in the absence of anchor domain Ciz1 retains the ability to promote initiation of DNA replication in isolated nuclei so attachment to the nuclear matrix is not essential for function. Expression of DNA replication and nuclear matrix anchor domains of Ciz1 are uncoupled and uneven at the transcript level in a wide range of common solid tumours, including breast and lung. In cell-based assays, recombinant anchor domain protein interferes with attachment of endogenous Ciz1 to the nuclear matrix, revealing a dominant negative effect that also impacts on nuclear matrix-recruitment of key components of the pre-replication complex. This suggests that Ciz1 normally plays a role in localizing initiation of DNA replication to the nuclear matrix. These findings implicate spatially unconstrained DNA replication as a source of nuclear disorder in cancer cells. We identified a variant Ciz1 isoform with alterations in the nuclear matrix attachment domain and tumour-restricted expression. RNAi-mediated selective inhibition of variant Ciz1 expression is sufficient to restrain the growth of tumour cells that express it, identifying variant Ciz1 as a functionally relevant driver of cell proliferation. We also present evidence that this form of Ciz1 is expressed in 34/35 lung tumours but not adjacent tissue, giving rise to stable protein quantifiable in less than a microlitre of patient plasma by western blot. Using two independent sets, with 170 and 160 samples, variant Ciz1 correctly identified stage 1 lung cancer patients with clinically useful accuracy. For set 1, mean variant Ciz1 level (+SD) in individuals without diagnosed tumours established a threshold that correctly classified 94% of small cell lung cancers (SCLC) and non-SCLC patients. Within set 2, comparison of stage 1 non-SCLC with asymptomatic age-matched smokers correctly classified 85% of patients, while comparison with individuals with benign lung nodules correctly classified 83% of patients. The data show that this cancer-specific, single marker is capable of indentifying early stage lung cancer within at-risk groups, without resort to invasive procedures. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-442. doi:1538-7445.AM2012-LB-442