Genetic evidence for the interaction between Bacillus anthracis-encoded phage receptors and their cognate phage-encoded receptor binding proteins

Bacteriophages such as γ and AP50c have been shown to infect strains of Bacillus anthracis with high specificity, and this feature has been exploited in the development of bacterial detection assays. To better understand the emergence of phage resistance, and thus the potential failure of such assays, it is important to identify the host and phage receptors necessary for attachment and entry. Using genetic approaches, the bacterial receptors of AP50c and γ have been identified as sap and GamR, respectively. A second AP50c-like phage, Wip1, also appears to use sap as a receptor. In parallel with this work, the cognate phage-encoded receptor binding proteins (RBPs) have also been identified (Gp14 for γ, P28 for AP50c, and P23 for Wip1); however, the strength of evidence supporting these protein–protein interactions varies, necessitating additional investigation. Here, we present genetic evidence further supporting the interaction between sap and the RBPs of AP50c and Wip1 using fluorescently tagged proteins and a panel of B. anthracis mutants. These results showed that the deletion of the sap gene, as well as the deletion of csaB, whose encoded protein anchors sap to the bacterial S-layer, resulted in the loss of RBP binding. Binding could then be rescued by expressing these genes in trans. We also found that the RBP of the γ-like prophage λBa03 relied on csaB activity for binding, possibly by a different mechanism. RBPλBa03 binding to B. anthracis cells was also unique in that it was not ablated by heat inactivation of vegetative cells, suggesting that its receptor is still functional following incubation at 98°C. These results extend our understanding of the diverse attachment and entry strategies used by B. anthracis phages, enabling future assay development

Forest biodiversity, ecosystem functioning and the provision of ecosystem services

Forests are critical habitats for biodiversity and they are also essential for the provision of a wide range of ecosystem services that are important to human well-being. There is increasing evidence that biodiversity contributes to forest ecosystem functioning and the provision of ecosystem services. Here we provide a review of forest ecosystem services including biomass production, habitat provisioning services, pollination, seed dispersal, resistance to wind storms, fire regulation and mitigation, pest regulation of native and invading insects, carbon sequestration, and cultural ecosystem services, in relation to forest type, structure and diversity. We also consider relationships between forest biodiversity and multifunctionality, and trade-offs among ecosystem services. We compare the concepts of ecosystem processes, functions and services to clarify their definitions. Our review of published studies indicates a lack of empirical studies that establish quantitative and causal relationships between forest biodiversity and many important ecosystem services. The literature is highly skewed; studies on provisioning of nutrition and energy, and on cultural services, delivered by mixed-species forests are under-represented. Planted forests offer ample opportunity for optimising their composition and diversity because replanting after harvesting is a recurring process. Planting mixed-species forests should be given more consideration as they are likely to provide a wider range of ecosystem services within the forest and for adjacent land uses. This review also serves as the introduction to this special issue of Biodiversity and Conservation on various aspects of forest biodiversity and ecosystem services

Herbivory By Species Of Trirhabda (Coleoptera, Chrysomelidae) On Solidago altissima (Asteraceae) - Variation Between Years

Volume: 83Start Page: 274End Page: 28

Host plants and seasonal abundance of adult Capraita subvittata (Coleoptera: Chrysomelidae: Alticinae)

Volume: 89Start Page: 818End Page: 82

Response of HeLa Cells to Selected Pesticides and Hallucinogens

Monolayer cultures of HeLa cells were used to monitor the effect of five liquid commercial insecticidal formulations (Raid®, Isotox®, Sevin®, Ortho-Klor 74®, and Malathion 50®, and two pure hallucinogenic chemicals (d-lysergic acid diethylamide or LSD and Δ-9-tetrahydrocannabinol or Δ-9-THC). HeLa cells were incubated for 48 hrs with different concentrations of the selected formulations or chemicals, after which the effect on cell culture growth was determined. Ortho-Klor74® was found to be the most toxic of the formulations or hallucinogens used in that it was 100.0% lethal to the HeLa cells at a concentration of 0.015 μl of liquid formulation per ml of cell growth medium (μl/ml). When HeLa cells were exposed to the same low concentration (0.015 μl/ml) of Raid®, Isotox®, and Malathion 50®, cell numbers increased. Sevin® had no effect on cell numbers at 0.015 μl/ml but enhanced cell numbers at 1.5 μl/ml. The lowest tested concentrations of the two hallucinogens produced no stimulation in \u27cell number\u27. As the concentrations of each formulation or hallucinogen were increased, the number of cells decreased. It was observed that Δ-9-THC (1.0 μl/ml) was seven times more toxic to HeLa cells than LSD (at 1.0 μg/ml). The investigated concentrations of each formulation or pure compound that had the least toxicity to the HeLa cells when compared to untreated controls were then used in further experiments to monitor the chemical\u27s effect on trichloroacetic acid precipitable nucleic acids and protein following a 48 hr incubation period with appropriate radioactive precursors and chemicals. When HeLa cells were exposed to Raid®, Isotox®, and Malathion 50® at 0.015 μl/ml and Sevin® at 1.5 μl/ml, the quantities of RNA, DNA, and protein in the HeLa cells increased. Both LSD (7.5 μg/ml) and Δ-9-THC (1.0 μg/ml) profoundly decreased HeLa cell nucleic acids and protein

Association of vines and trees in second-growth forest

In a fragment of second-growth forest in Massachusetts, woody vines (mostly Rhus radicans) grew on 45% of the trees, and were disproportionately abundant on large trees and on trees near the edge of the fragment. Among hickories, Carya ovata, a species known for its unique shaggy bark, hosted more vines than C. glabra