Role of fungi in freshwater ecosystems

There are more than 600 species of freshwater fungi with a greater number known from temperate, as compared to tropical, regions. Three main groups can be considered which include Ingoldian fungi, aquatic ascomycetes and non-Ingoldian hyphomycetes, chytrids and, oomycetes. The fungi occurring in lentic habitats mostly differ from those occurring in lotic habitats. Although there is no comprehensive work dealing with the biogeography of all groups of freshwater fungi, their distribution probably follows that of Ingoldian fungi, which are either cosmopolitan, restricted to pantemperate or pantropical regions, or in a few cases, have a restricted distribution. Freshwater fungi are thought to have evolved from terrestrial ancestors. Many species are clearly adapted to life in freshwater as their propagules have specialised aquatic dispersal abilities. Freshwater fungi are involved in the decay of wood and leafy material and also cause diseases of plants and animals. These areas are briefly reviewed. Gaps in our knowledge of freshwater fungi are discussed and areas in need of research are suggested.     

Analysis of all protein amino acids as their tert.-butyldimethylsilyl derivatives by gas-liquid chromatography

A gas chromatographic method for the separation and quantitation of the 20 protein amino acids is described using N-methyl-N(tert.-butyldimethylsilyl)trifluoroacetamide, with 1% tert.-butyldimethylchlorosilane as catalyst, to prepare the tert.-butyldimethylsilyl amino acid derivatives. Alkylsilylation of amino acids proceeds at 140 degrees C in 20 min. The derivatives formed in the one-step reaction are used directly for gas-liquid chromatographic analysis, using a flame-ionization detector, without prior isolation or purification. Complete separation and quantitation of all protein amino acids are readily achieved using a 15-m DB-5 capillary column. Strict linearity extends from less than 15 to about 100 ng for all amino acids except Arg, which has a linear range from 50 to 300 ng. The limits of detection, however, range from one to several hundred nanograms. The method was used to analyze the free amino acid pool in carnation petals.     

Enhancement of transient gene expression by fed-batch culture of HEK 293 EBNA1 cells in suspension

Enhanced green fluorescence protein (GFP) and erythropoietin (EPO) were used as reporters to assess and improve transient gene expression in HEK 293 EBNA1 cells. The production of EPO only lasted 3 days and reached 18.1 mg/l in suspension cultures in 1 l batch bioreactors. However, GFP expression examined in well-plate experiments persisted for 12 days in transfected cells but decreased rapidly within the next 15 days. These results suggest that the retaining of a plasmid in cells may not be a limiting factor for protein expression in large-scale transient transfection. To improve cell maintenance and protein expression, a fed-batch culture was performed using an enriched medium, a mixture of equal volumes of 293 SFM II medium and a 5 × amino acid solution prepared based on DMEM/F12 medium formula. EPO reached 33.6 mg/l, representing 86% increase over that of the batch culture. Moreover, the total amount of EPO produced was increased by 165% in view of the volume increase in the fed-batch culture. The serum-free medium used in this work enables cells growing well and transfection without medium change. Thus, the process reported here is simple and easy to scale up.     

Influence of different macronutrient solutions and growth regulators on micropropagation of juvenile shape Acacia mangium and shape Paraserianthes falcataria explants

The influence of five different macronutrient formulations and various growth regulators on micropropagation of single node explants from Acacia mangium and Paraserianthes falcataria seedlings was examined after 4 weeks and 8 weeks in vitro. The experiment was repeated 4 months later. On media lacking growth regulators, growth and development were significantly influenced by the different macronutrient solutions tested, although morphogenic responses could vary according to the species. For instance, P. falcataria displayed a greater ability for adventitious rooting than A. mangium. Overall, Knop macronutrient solution induced the weakest responses. Explant responsiveness was significantly influenced by the addition of 2.2 or 4.4 μM 6-benzyladenine combined with either 1.4 or 2.3 μM kinetin, 1.5 or 2.5 μM indolebutyric acid or 1.6 or 2.7 μM naphthaleneacetic acid. The various combinations of growth regulators tested were shown to inhibit the rooting ability of the explants, while stimulating the production of basal shoots for both species, and of axillary shoots only for A. mangium. In such experimental conditions, A. mangium displayed overall a greater potential for micropropagation than P. falcataria. This revised version was published online in June 2006 with corrections to the Cover Date.     

Scabies and Bacterial Superinfection among American Samoan Children, 2011–2012

BackgroundScabies, a highly pruritic and contagious mite infestation of the skin, is endemic among tropical regions and causes a substantial proportion of skin disease among lower-income countries. Delayed treatment can lead to bacterial superinfection, and treatment of close contacts is necessary to prevent reinfestation. We describe scabies incidence and superinfection among children in American Samoa (AS) to support scabies control recommendations.Conclusions/SignificanceScabies and its sequelae cause substantial morbidity among AS children. Bacterial superinfection prevalence and frequent reinfestations highlight the importance of diagnosing scabies and early treatment of patients and close contacts. Investigating why certain AS counties have a lower scabies incidence might help guide recommendations for improving scabies control among counties with a higher incidence. We recommend interventions targeting infants and young children who have frequent close family contact.     

Modeling Nociception in Zebrafish: A Way Forward for Unbiased Analgesic Discovery

Acute and chronic pain conditions are often debilitating, inflicting severe physiological, emotional and economic costs and affect a large percentage of the global population. However, the development of therapeutic analgesic agents based primarily on targeted drug development has been largely ineffective. An alternative approach to analgesic development would be to develop low cost, high throughput, untargeted animal based behavioral screens that model complex nociceptive behaviors in which to screen for analgesic compounds. Here we describe the development of a behavioral based assay in zebrafish larvae that is effective in identifying small molecule compounds with analgesic properties. In a place aversion assay, which likely utilizes supraspinal neuronal circuitry, individually arrayed zebrafish larvae show temperature-dependent aversion to increasing and decreasing temperatures deviating from rearing temperature. Modeling thermal hyperalgesia, the addition of the noxious inflammatory compound and TRPA1 agonist allyl isothiocyanate sensitized heat aversion and reversed cool aversion leading larvae to avoid rearing temperature in favor of otherwise acutely aversive cooler temperatures. We show that small molecules with known analgesic properties are able to inhibit acute and/or sensitized temperature aversion.     

trans-Activation of the human T-cell leukemia virus long terminal repeat correlates with expression of the x-lor protein.

Cell lines established directly from adult T-cell leukemia-lymphoma patients or immortalized by human T-cell leukemia virus type I (HTLV-I) in vitro that do not produce complete HTLV virions were characterized both for the content of viral proteins and for the presence of trans-acting factors activating gene expression under the control of the HTLV long terminal repeat. The expression of the 42-kilodalton HTLV x-lor product correlated with trans-activation of the long terminal repeat. The implications of this study for understanding the role of the HTLV x-lor product in the initiation and maintenance of T-lymphocyte transformation are discussed.     

Expression of the x-lor gene of human T-cell leukemia virus I in Escherichia coli.

The 3'-terminal regions of the human T-cell leukemia virus I (HTLV-I) and HTLV-II genomes encode a novel gene product. We showed that expression of this region fused to the beta-galactosidase gene in bacteria produces a protein recognized by adult T-cell leukemia-lymphoma patient sera. Rabbit antibodies raised against this protein specifically precipitated the 42-kilodalton x-lor gene protein from HTLV-I-infected cells.