Microbial retention of mercury from waste streams in a laboratory column containing merA gene bacteria

Abstract: The microorganisms used for the mercury retention experiments were natural isolates and genetically engineered bacteria. All mercury-resistant strains contained the merA gene. Column experiments with these strains were carried out by immobilizing them on different support materials. To obtain kinetic data of the reductase activity for whole cells and the crude extract, batch experiments were carried out under different conditions.     

Differential regulated expression of keratinocyte growth factor and its receptor in experimental and human liver fibrosis

BACKGROUND AND AIM: Immunomodulatory and protective properties have been identified for the keratinocyte growth factor (KGF). For hepatocytes, pro-proliferative and anti-apoptotic effects of this growth factor have been reported in vitro. This study was designed to characterize a putative role of KGF in observed histomorphological changes in both, human and experimental liver fibrosis. METHODS: Liver fibrosis and cirrhosis was induced in rats by repetitive exposure to phenobarbitone and increasing doses of carbon tetrachloride. Human samples were obtained from patients undergoing surgery for partial hepatectomy or transplantation. Organ samples were scored for inflammation and morphological changes. Expression of KGF and its receptor (KGFR) mRNA was quantified by real-time RT-PCR. Protein expression and receptor phosphorylation was determined by Western blot analysis. In-situ hybridization and immunohistochemistry were utilized to determine distribution of KGF and KGFR in the liver. RESULTS: Expression of KGF was significantly increased in damaged liver tissue in correlation to the degree of fibrosis, whereas expression of the receptor was up-regulated in early stages of liver fibrosis and down-regulated in cirrhotic organs. Protein expression of this growth factor and its receptor correlated with the alterations in mRNA. KGF expression was restricted to mesenchymal cells, whereas expression of KGFR was detected on hepatocytes only. CONCLUSION: The expression of KGF and KGFR is differentially and significantly regulated in damaged liver tissue. This growth factor might therefore not only contribute to morphological alterations but also regeneration of liver parenchyma most likely mediated by indirect mechanisms of action.     

Contributions to the faunistics and bionomics of Staphylinidae (Coleoptera) in northeastern North America: discoveries made through study of the University of Guelph Insect Collection, Ontario, Canada

Staphylinidae (Rove Beetles) from northeastern North America deposited in the University of Guelph Insect Collection (Ontario, Canada) were curated from 2008-2010 by the first author. The identification of this material has resulted in the recognition of thirty-five new provincial or state records, six new Canadian records, one new record for the United States and two new records for eastern Canada. All records are for subfamilies other than Aleocharinae and Pselaphinae, which will be treated in future publications as collaborative projects. Range expansions of ten exotic species to additional provinces and states are reported. The known distributions of each species in northeastern North America are summarized and presented as maps, and those species with a distinctive habitus are illustrated with color photographs. Genitalia and/or secondary sexual characters are illustrated for those species currently only identifiable on the basis of dissected males. The majority of the new records are in groups that have been recently revised, demonstrating the importance of curation and local insect surveys to the understanding of biodiversity, even for taxa and areas considered 'relatively well-known'.     

Guilty by association: an evaluation of millipedes as pests of carrot and sweet potato

An evaluation of the pest potential of millipede species occurring in Ontario sweet potato and carrot fields was conducted in response to recent grower concerns about the presence of millipedes in close proximity to damaged vegetables. This study is the first North American survey of millipedes on arable soils and the first evaluation of North American millipede damage to sweet potatoes and carrots. Through field surveys, Cylindroiulus caeruleocinctus was found to be the dominant millipede species in Ontario sweet potatoes and carrots. Fields were surveyed over the growing season, and the factors important to each species’ abundance were evaluated using Minimum AIC Estimation (MAICE). Post‐harvest damage assessments were performed, and MAICE analysis was used to determine which arthropod and environmental parameters were most important in explaining damage to sweet potatoes and carrots. Wireworm (Elateridae) abundance was consistently found to explain root damage better than C. caeruleocinctus abundance, and it is concluded that the majority of field‐observed damage was caused by wireworms. C. caeruleocinctus was negatively correlated with both wireworms and damage in carrot fields and is not likely to be a pest of that vegetable. However, abundance of C. caeruleocinctus in sweet potatoes was positively correlated with both wireworms and damage. This species may cause some damage to sweet potato tubers under field conditions, but management tactics should focus on wireworms as the primary source of damage.     

Colmation and Depth Filtration within Streambeds: Retention of Particles in Hyporheic Interstices

Colmation refers to the retention processes that can lead to the clogging of the top layer of channel sediments and decolmation refers to the resuspension of deposited fine particles. Internal colmation, clogging of the interstices directly below the armor layer, may form a thin seal that disconnects surface water from hyporheic water by inhibiting exchange processes. The settling of particles under low flow conditions can cause external colmation. Colmated channel sediments are characterized by reduced porosity and hydraulic conductivity as well as by a consolidated texture. The term ‘depth filtration’ refers to the transport and storage of fine matrix sediments in interstitial layers. Depth filtration is of significance for the transport of colloidal and fine particulate inorganic as well as organic matter within the hyporheic interstices and into the alluvial aquifer. The role of depth filtration is assessed for the content (given in mg per liter) of matrix fine particles retained in the coarse framework sediment of a gravel-bed river in Switzerland. Sediment samples were taken by freeze-coring with liquid nitrogen down to 70 cm depth and by piezometers down to 150 cm depth. Seventy-two percent of the mobile matrix fine particles were smaller than 0.1 mm and 50% were smaller than 0.03 mm. The content of fines tended to increase with depth, although higher accumulations were found at intermediate depths in sediments influenced by exfiltrating ground water. Interstitial detrital particles >90 μm showed vertical distribution patterns opposing those of total particles. These relationships revealed a differential significance of import, storage, and transport within three types of hydrological exchange zones (infiltration, horizontal advection, exfiltration) in the cross-section of the stream.     

Immune Evasion,Stress Resistance,and Efficient Nutrient Acquisition Are Crucial for Intracellular Survival of Candida glabrata within Macrophages

Candida glabrata is both a human fungal commensal and an opportunistic pathogen which can withstand activities of the immune system. For example, C. glabrata can survive phagocytosis and replicates within macrophages. However, the mechanisms underlying intracellular survival remain unclear. In this work, we used a functional genomic approach to identify C. glabrata determinants necessary for survival within human monocyte-derived macrophages by screening a set of 433 deletion mutants. We identified 23 genes which are required to resist killing by macrophages. Based on homologies to Saccharomyces cerevisiae orthologs, these genes are putatively involved in cell wall biosynthesis, calcium homeostasis, nutritional and stress response, protein glycosylation, or iron homeostasis. Mutants were further characterized using a series of in vitro assays to elucidate the genes'' functions in survival. We investigated different parameters of C. glabrata-phagocyte interactions: uptake by macrophages, replication within macrophages, phagosomal pH, and recognition of mutant cells by macrophages as indicated by production of reactive oxygen species and tumor necrosis factor alpha (TNF-α). We further studied the cell surface integrity of mutant cells, their ability to grow under nutrient-limited conditions, and their susceptibility to stress conditions mirroring the harsh environment inside a phagosome. Additionally, resistance to killing by neutrophils was analyzed. Our data support the view that immune evasion is a key aspect of C. glabrata virulence and that increased immune recognition causes increased antifungal activities by macrophages. Furthermore, stress resistance and efficient nutrient acquisition, in particular, iron uptake, are crucial for intraphagosomal survival of C. glabrata.     

Systematic Phenotyping of a Large-Scale Candida glabrata Deletion Collection Reveals Novel Antifungal Tolerance Genes

The opportunistic fungal pathogen Candida glabrata is a frequent cause of candidiasis, causing infections ranging from superficial to life-threatening disseminated disease. The inherent tolerance of C. glabrata to azole drugs makes this pathogen a serious clinical threat. To identify novel genes implicated in antifungal drug tolerance, we have constructed a large-scale C. glabrata deletion library consisting of 619 unique, individually bar-coded mutant strains, each lacking one specific gene, all together representing almost 12% of the genome. Functional analysis of this library in a series of phenotypic and fitness assays identified numerous genes required for growth of C. glabrata under normal or specific stress conditions, as well as a number of novel genes involved in tolerance to clinically important antifungal drugs such as azoles and echinocandins. We identified 38 deletion strains displaying strongly increased susceptibility to caspofungin, 28 of which encoding proteins that have not previously been linked to echinocandin tolerance. Our results demonstrate the potential of the C. glabrata mutant collection as a valuable resource in functional genomics studies of this important fungal pathogen of humans, and to facilitate the identification of putative novel antifungal drug target and virulence genes.     

Phylogeny of the hyper‐diverse rove beetle subtribe Philonthina with implications for classification of the tribe Staphylinini (Coleoptera: Staphylinidae)

With 71 genera and over 2700 described species, Philonthina is the most speciose subtribe of rove beetle tribe Staphylinini and forms a major component of the largest remaining higher systematics challenge in Staphylinini, the ‘Staphylinini propria’ clade. A related systematics issue concerns the position of the genus Holisus (Hyptiomina), which was recovered within the Neotropical philonthine lineage in several recent analyses of morphology. With the aims of resolving the phylogeny of Philonthina and the position and, thus, validity of Hyptiomina, we performed phylogenetic analyses of the tribe Staphylinini based on molecular (six genes, 4471 bp) and morphological (113 characters) data including 138 taxa from all relevant lineages of Staphylinini. We found that ‘Staphylinini propria’ is a monophylum consisting of six lineages: current subtribes Anisolinina, Philonthina, Staphylinina and Xanthopygina; and two new subtribes, Algonina Schillhammer and Brunke and Philothalpina Chatzimanolis and Brunke. While the previously hypothesized Neotropical lineage of Philonthina was corroborated, Holisus was recovered as a separate subtribe, outside of Philonthina, within an informal ‘Southern Hemisphere clade’. Based on our analyses, we propose tentative new concepts of the polyphyletic genera Belonuchus and Philonthus. We propose the following taxonomic changes: synonymy of the subtribes Staphylinina Latreille (valid name) and Eucibdelina Sharp; resurrection of genera Barypalpus Cameron and Trapeziderus Motschulsky from synonymy with Rientis Sharp and Belonuchus Nordmann, respectively; transfer of 38 Belonuchus species, 16 Hesperus Fauvel species and one Philonthus Stephens species to Trapeziderus as new combinations; transfer of two Hesperus species to Eccoptolonthus Bernhauer as new combinations; transfer of one Belonuchus species to Paederomimus Sharp as a new combination; and transfer of Pridonius Blackwelder new status from its position as a subgenus of Quedius (subtribe Quediina) to Philonthina as a genus, and new combinations for its two described species.