Mycorrhizal fungi of Eucalyptus in the North Island of New Zealand

Fungal sporocarps of Hydnangium carneum Wallr., Laccaria laccata (Scop. ex Fr.) Berk. ex Br., Scleroderma spp, Hymenogaster spp., Hysterangium spp, Cortinarius spp, etc. were found to be associated with five species of eucalypts Eucalyptus delegatensis R.T. Bak., E. regnans F. Muell., E. nitens Maiden, E.fastigata Deane et Maiden, and E. saligna Sm.) in nurseries or stands in the North Island of New Zealand.A total of 5345 mycorrhizal pieces were plated out in isolation studies. More than 47% of these pieces remained free of fungal outgrowth, 16% yielded dark sterile mycelia, 7% yielded hyaline sterile fungi, 17% produced sporing Fungi Imperfecti, 5.8% were basidiomycetous fungi identified as H. carneum, Scleroderma spp, Paxillus sp. and Hymenogaster albus (Klotzsch) Berk. et Br., and 5.9% were unidentified basidiomycetes.Mycorrhizas were synthesized on eucalypt seedlings by 12 identified basidiomycetes which form sporocarps in eucalypt stands and 12 unidentified basidiomycetes isolated from the mycorrhizas. Under the test conditions two Cortinarius spp and one unidentified basidiomycete did not form mycorrhizas.The results indicate a possible importance of H. carneum as a mycorrhizal fungus of eucalypts in the North Island of New Zealand.     

Cycling of volatile mercury in temperate lakes

The cycling of dissolved gaseous Hg (DGM) has been examined in our studies of the troposphericHg cycle, air-water exchange and their importance to the biogeochemical behavior and fate of Hg in temperate lakes. Five seepage lakes in northcentral Wisconsin, ranging in pH from 4.7 to 7.2, have been studied under a variety of limnological conditions which included the following seasonal periods: summer (peak stratification), fall (following turnover) and late winter (under ice). Analytically, DGM was determined after purging lake water with argon and collecting the volatile Hg fraction on gold coated sand. The Hg collections were analysed by pyrolysis in a two-stage Au amalgamation gas train with detection by atomic fluorescence spectroscopy (AFS). In addition, chemical speciation of the volatile fraction has been achieved by trapping on a nondestructive substrate followed by gas chromatographic separation and AFS detection. The DGM consists principally of elemental Hg (Hg^o) under all sampling conditions, with no significant contribution from volatile organic Hg species (detection limit of 3 femtomolar). Atmospheric gaseous Hg, which also consists principally of Hg^o, was measured and the air-water partitioning determined. In general, the lake waters have been supersaturated with Hg^o relative to the atmosphere. Supersaturation was greater in the summer, ranging from ca. 1.4 to 12 times (x) the saturation concentration. During the other sampling periods, Hg^o ranged from saturation to ca. 7x the equilibrium concentration. The flux of Hg from the lakes due to gas evasion is significant and is estimated at approximately 10% of the annual atmospheric input of Hg to the lakes. An apparent relationship between Hg^o and pH has been observed with lakes of lower pH having smaller Hg^o concentrations.     

A preliminary mercury budget for Narragansett Bay (Rhode Island,USA)

The distribution of total Hg (Hg_t) and reactive (Hg_R) in Narragansett Bay, fresh water tributaries and point source discharges was determined during a synoptic survey, carried out in April, 1986. A Hg budget which includes fluvial inputs and atmospheric Hg deposition was constructed and the estuarine behavior of Hg assessed.     

Formation of regulatory patterns during signal propagation in a Mammalian cellular network

We developed a model of 545 components (nodes) and 1259 interactions representing signaling pathways and cellular machines in the hippocampal CA1 neuron. Using graph theory methods, we analyzed ligand-induced signal flow through the system. Specification of input and output nodes allowed us to identify functional modules. Networking resulted in the emergence of regulatory motifs, such as positive and negative feedback and feedforward loops, that process information. Key regulators of plasticity were highly connected nodes required for the formation of regulatory motifs, indicating the potential importance of such motifs in determining cellular choices between homeostasis and plasticity.     

Natural Colonization of Rice by Arbuscular Mycorrhizal Fungi in Different Production Areas

Interactions between plants and soil microorganisms can influence the other interactions in which plants participate, including interactions with herbivores. Many fungi, including arbuscular mycorrhizal fungi(AMF), form symbiotic relationships with the roots they inhabit, and potentially alter defense against pests. The objective of this study was to document the extent of root colonization by AMF on non-flooded rice plants grown under conditions typical of commercial fields. We hypothesized that AMF naturally colonized rice plants in different rice producing field locations. Rice plant samples were collected from areas across the southern United States, including Texas, Mississippi, Arkansas and two research stations in Louisiana. We quantified the amount of AMF colonization in insecticide-free rice plants over three consecutive years(2014–2016). The results revealed natural colonization of AMF in all rice producing areas. In all the three years of survey, rice-AMF associations were the greatest in Arkansas followed by Mississippi and Texas. This research will help draw attention to natural colonization of AMF in rice producing areas that can impact future rice research and production by facilitating agricultural exploitation of the symbiosis.     

Comparative Study of Proximate,Chemical and Physicochemical Properties of Less Explored Tropical Leafy Vegetables

The list of underutilized green leafy vegetables is enormous: ranging from commonly consumed and underutilized vegetables. There are data on commonly consumed vegetables, but information is sparse on nutritional, chemical and anti-nutritional properties of less explored vegetables. This work aimed to evaluate some attributes of less explored or underutilized leafy vegetables. Some nutritional and anti-nutritional contents of 10 under-utilized leafy vegetables(Amaranthus spinosus Linnaeus, Basella alba Linnaeus, Corchorous tridens L., Cyrtosperma senegalense(Schott), Erigeron floribundus Sch, Hoslundia opposita Vahl, Lagenaria siceraria(Molina) Standl, Ocimum basilicum L., Solanum aethiopicum L. and Talinum portulacifolium(Forssk.) Asch. ex Schweinf) were investigated. Cyrtosperma senegalense had the highest protein value(5.93%). Hoslundia opposita had the highest fat content(0.54%). Amaranthus spinosus was high in β-carotene content(346.3 mg · 100 g-1); Cyrtosperma senegalense had the highest moisture content. A. spinosus had the highest ascorbic acid content(108.1 mg · 100 g-1). The highest tannin level(0.0057%) was found in C. senegalense and the lowest(0.0003%) was found in Solanum aethiopicum. Saponin was the highest in C. tridens(0.0052%) and the lowest in T. portulacifolium(0.00014%). C. senegalense and S. aethiopicum had their highest and the lowest phytate values, respectively. Although anti-nutrients could interfere with nutrient utilization, their values in these vegetables were not at toxic levels.