Bacterial diversity and ecosystem function of filamentous microbial mats from aphotic (cave) sulfidic springs dominated by chemolithoautotrophic "Epsilonproteobacteria"

Filamentous microbial mats from three aphotic sulfidic springs in Lower Kane Cave, Wyoming, were assessed with regard to bacterial diversity, community structure, and ecosystem function using a 16S rDNA-based phylogenetic approach combined with elemental content and stable carbon isotope ratio analyses. The most prevalent mat morphotype consisted of white filament bundles, with low C:N ratios (3.5-5.4) and high sulfur content (16.1-51.2%). White filament bundles and two other mat morphotypes had organic carbon isotope values (mean delta13C=-34.7 per thousand, 1sigma=3.6) consistent with chemolithoautotrophic carbon fixation from a dissolved inorganic carbon reservoir (cave water, mean delta13C=-7.4 per thousand for two springs, n=8). Bacterial diversity was low overall in the clone libraries, and the most abundant taxonomic group was affiliated with the "Epsilonproteobacteria" (68%), with other bacterial sequences affiliated with Gammaproteobacteria (12.2%), Betaproteobacteria (11.7%), Deltaproteobacteria (0.8%), and the Acidobacterium (5.6%) and Bacteriodetes/Chlorobi (1.7%) divisions. Six distinct epsilonproteobacterial taxonomic groups were identified from the microbial mats. Epsilonproteobacterial and bacterial group abundances and community structure shifted from the spring orifices downstream, corresponding to changes in dissolved sulfide and oxygen concentrations and metabolic requirements of certain bacterial groups. Most of the clone sequences for epsilonproteobacterial groups were retrieved from areas with high sulfide and low oxygen concentrations, whereas Thiothrix spp. and Thiobacillus spp. had higher retrieved clone abundances where conditions of low sulfide and high oxygen concentrations were measured. Genetic and metabolic diversity among the "Epsilonproteobacteria" maximizes overall cave ecosystem function, and these organisms play a significant role in providing chemolithoautotrophic energy to the otherwise nutrient-poor cave habitat. Our results demonstrate that sulfur cycling supports subsurface ecosystems through chemolithoautotrophy and expand the evolutionary and ecological views of "Epsilonproteobacteria" in terrestrial habitats.     

Lamin A/C binding protein LAP2alpha is required for nuclear anchorage of retinoblastoma protein

The phosphorylation-dependent anchorage of retinoblastoma protein Rb in the nucleus is essential for its function. We show that its pocket C domain is both necessary and sufficient for nuclear anchorage by transiently expressing green fluorescent protein (GFP) chimeras of Rb fragments in tissue culture cells and by extracting the cells with hypotonic solutions. Solid phase binding assays using glutathione S-transferase-fusion of Rb pockets A, B, and C revealed a direct association of lamin C exclusively to pocket C. Lamina-associated polypeptide (LAP) 2alpha, a binding partner of lamins A/C, bound strongly to pocket C and weakly to pocket B. When LAP2alpha was immunoprecipitated from soluble nuclear fractions, lamins A/C and hypophosphorylated Rb were coprecipitated efficiently. Similarly, immunoprecipitation of expressed GFP-Rb fragments by using anti-GFP antibodies coprecipitated LAP2alpha, provided that pocket C was present in the GFP chimeras. On redistribution of endogenous lamin A/C and LAP2alpha into nuclear aggregates by overexpressing dominant negative lamin mutants in tissue culture cells, Rb was also sequestered into these aggregates. In primary skin fibroblasts, LAP2alpha is expressed in a growth-dependent manner. Anchorage of hypophosphorylated Rb in the nucleus was weakened significantly in the absence of LAP2alpha. Together, these data suggest that hypophosphorylated Rb is anchored in the nucleus by the interaction of pocket C with LAP2alpha-lamin A/C complexes.     

Iron and the redox status of the lungs

Iron is an element essential for the survival of most aerobic organisms. However, when its availability is not adequately controlled, iron, can catalyze the formation of a range of aggressive and damaging reactive oxygen species, and act as a microbial growth promoter. Depending on the concentrations formed such species can cause molecular damage or influence redox signaling mechanisms. This review describes recent knowledge concerning iron metabolism in the lung, during both health and disease. In the lower part of the lung a small redox active pool of iron is required for reasons that are at present unclear, but may be related to antimicrobial functions. When the concentration of iron is increased in the lung (usually because of environmental exposure), iron is deleterious and contributes to a range of chronic and acute respiratory diseases. Moreover, aberrant regulation of iron metabolism, and/or deficient antioxidant protection, is also associated with acute lung diseases, such as the acute respiratory distress syndrome (ARDS). Iron, with the consequent production of reactive oxygen species (ROS), microbial growth promotion, and adverse signaling is strongly implicated as a major contributor to the pathogenesis of numerous disease processes involving the lung. Heme oxgenase, an enzyme that produces reactive iron from heme catabolism, is also briefly discussed in relation to lung disease.     

Ethnomedicine and ethnobotany of fright,a Caribbean culture-bound psychiatric syndrome

Background

Plant species have long been used as principal ingredients of traditional medicine in far-west Nepal. The medicinal plants with ethnomedicinal values are currently being screened for their therapeutic potential but their data and information are inadequately compared and analyzed with the Ayurveda and the phytochemical findings.

Methods

The present study evaluated ethnomedicinal plants and their uses following literature review, comparison, field observations, and analysis. Comparison was made against earlier standard literature of medicinal plants and ethnomedicine of the same area, the common uses of the Ayurveda and the latest common phytochemical findings. The field study for primary data collection was carried out from 2006-2008.

Results

The herbal medicine in far-west Nepal is the basis of treatment of most illness through traditional knowledge. The medicine is made available via ancient, natural health care practices such as tribal lore, home herbal remedy, and the Baidhya, Ayurveda and Amchi systems. The traditional herbal medicine has not only survived but also thrived in the trans-cultural environment with its intermixture of ethnic traditions and beliefs. The present assessment showed that traditional herbal medicine has flourished in rural areas where modern medicine is parsimoniously accessed because of the high cost and long travel time to health center. Of the 48 Nepalese medicinal plants assessed in the present communication, about half of the species showed affinity with the common uses of the Ayurveda, earlier studies and the latest phytochemical findings. The folk uses of Acacia catechu for cold and cough, Aconitum spicatum as an analgesic, Aesculus indica for joint pain, Andrographis paniculata for fever, Anisomeles indica for urinary affections, Azadirachta indica for fever, Euphorbia hirta for asthma, Taxus wallichiana for tumor control, and Tinospora sinensis for diabetes are consistent with the latest pharmacological findings, common Ayurvedic and earlier uses.

Conclusions

Although traditional herbal medicine is only a primary means of health care in far-west Nepal, the medicine has been pursued indigenously with complementing pharmacology and the Ayurveda. Therefore, further pharmacological evaluation of traditional herbal medicine deserves more attention.     

Phytoplankton assemblages across the marine to low-salinity transition zone in a blackwater dominated estuary

Along the salinity gradient between the freshwater reach ofthe Suwannee River and the marine waters of the Gulf of Mexico,the spatial and temporal composition and abundance of phytoplanktonwas examined in relation to physical and chemical water-columnvariables (i.e. salinity, nutrient and light availability andtemperature). The goal of this study was to explore the applicabilityof the concepts of ecotone and ecocline to the distributionof phytoplankton. This was undertaken in a relatively open estuarydominated by a tannin-colored river, the Suwannee River, alongthe central northwest coast of Florida, USA. Hierarchical clusteranalysis and non-metric multi-dimensional scaling (MDS) wasused to define biologically distinct regions within the estuarybased on the composition of phytoplankton. Variations in phytoplanktonassemblages in relation to environmental variables were investigatedusing a canonical correspondence analysis. The results indicatethat in addition to the alignment of phytoplankton compositionalong a salinity gradient, several key environmental factorsinfluence phytoplankton assemblages within hydrologically distinctregions of the estuary supporting an ecocline view. However,the distribution of dinoflagellate assemblages were in contrastto the more temporally fluid spatial distributions of cyanobacteriaand diatoms in the Suwannee River estuary. The spatially definednature of the dinoflagellate assemblages was more characteristicof an ecotone rather than an ecocline.     

Regulatory interactions between two actin nucleators, Spire and Cappuccino

Spire and Cappuccino are actin nucleation factors that are required to establish the polarity of Drosophila melanogaster oocytes. Their mutant phenotypes are nearly identical, and the proteins interact biochemically. We find that the interaction between Spire and Cappuccino family proteins is conserved across metazoan phyla and is mediated by binding of the formin homology 2 (FH2) domain from Cappuccino (or its mammalian homologue formin-2) to the kinase noncatalytic C-lobe domain (KIND) from Spire. In vitro, the KIND domain is a monomeric folded domain. Two KIND monomers bind each FH2 dimer with nanomolar affinity and strongly inhibit actin nucleation by the FH2 domain. In contrast, formation of the Spire-Cappuccino complex enhances actin nucleation by Spire. In Drosophila oocytes, Spire localizes to the cortex early in oogenesis and disappears around stage 10b, coincident with the onset of cytoplasmic streaming.