20,314 research outputs found
The human milk protein-lipid complex HAMLET disrupts glycolysis and induces death in Streptococcus pneumoniae
HAMLET is a complex of human a-lactalbumin (ALA) and oleic acid and kills several Gram-positive bacteria by a mechanism that bears resemblance to apoptosis in eukaryotic cells. To identify HAMLET's bacterial targets, here we used Streptococcus pneumoniae as a model organism and employed a proteomic approach that identified several potential candidates. Two of these targets were the glycolytic enzymes fructose bis-phosphate aldolase (FBPA) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Treatment of pneumococci with HAMLET immediately inhibited their ATP and lactate production, suggesting that HAMLET inhibits glycolysis. This observation was supported by experiments with recombinant bacterial enzymes, along with biochemical and bacterial viability assays, indicating that HAMLET's activity is partially inhibited by high glucose-mediated stimulation of glycolysis but enhanced in the presence of the glycolysis inhibitor 2-deoxyglucose. Both HAMLET and ALA bound directly to each glycolytic enzyme in solution and solid phase assays and effectively inhibited their enzymatic activities. In contrast, oleic acid alone had little to no inhibitory activity. However, ALA alone also exhibited no bactericidal activity and did not block glycolysis in whole cells, suggesting a role for the lipid moiety in the internalization of HAMLET into the bacterial cells to reach its target(s). This was verified by inhibition of enzyme activity in whole cells after HAMLET but not ALA exposure. The results of this study suggest that part of HAMLET's antibacterial activity relates to its ability to target and inhibit glycolytic enzymes, providing an example of a natural antimicrobial agent that specifically targets glycolysis
Euhrychiopsis lecontei distribution, abundance, and experimental augmentations for Eurasian watermilfoil control in Wisconsin lakes
The specialist aquatic herbivore Euhrychiopsis lecontei (Dietz)
is currently being researched as a potential biological control
agent for Eurasian watermilfoil (Myriophyllum spicatum L.).
Our research in Wisconsin focused on 1) determining milfoil
weevil distribution across lakes, 2) assessing limnological
characteristics associated with their abundance, and 3) evaluating
milfoil weevil augmentation as a practical management
tool for controlling Eurasian watermilfoil
Riordan Paths and Derangements
Riordan paths are Motzkin paths without horizontal steps on the x-axis. We
establish a correspondence between Riordan paths and
-avoiding derangements. We also present a combinatorial proof
of a recurrence relation for the Riordan numbers in the spirit of the
Foata-Zeilberger proof of a recurrence relation on the Schr\"oder numbers.Comment: 9 pages, 2 figure
New Records for \u3ci\u3eEuhrychiopsis Lecontei\u3c/i\u3e (Coleoptera: Curculionidae) and Their Densities in Wisconsin Lakes
The native aquatic weevil, Euhrychiopsis lecontei is currently being researched as a potential biological control for the exotic aquatic macrophyte Eurasian watermilfoil (Myriophyllum spicatum), yet little is known about its specific distribution in North America. In this study, E. lecontei was collected in 25 of 27 lakes surveyed for the weevil in Wisconsin, greatly increasing the known distribution of the species in this state. E. lecontei densities evaluated in 14 Wisconsin lakes ranged from \u3c0.01 to 1.91 weevils per apical stem of milfoil. These new records indicate that E. lecontei is widespread throughout Wisconsin and is associated with natural declines of M. spicatum in some lakes. Additional sampling for E. lecontei and research on its ecology and life history are needed to understand the role of this organism in aquatic ecosystems
Temporal and spatial changes in milfoil distribution and biomass associated with weevils in Fish Lake, WI
During the course of an eight year monitoring effort, the
Wisconsin Department of Natural Resources documented a
significant decline in milfoil biomass and distribution in Fish
Lake, Wisconsin. Average milfoil biomass declined by 40-
50% from 374-524 g dw m
-2
during 1991-93 to 265 g dw m
-2
during both 1994 and 1995. Milfoil recovered fully in 1996-
98 to 446- 564 g dw m
-2
. The size of the milfoil bed, as discerned
from aerial photographs, shrank from a maximum
coverage of 40 ha in 1991 to less than 20 ha during 1995.
During the “crash” of 1994-95, milfoil plants exhibited typical
signs of weevil-induced damage, including darkened, brittle,
hollowed-out growing tips, and the arching and collapse
of stems associated with loss of buoyancy. Monitoring of weevils
and stem damage during 1995-98 showed highest densities
and heaviest damage occurred near shore and subsequently
fanned out into deeper water from core infestation
sites each spring. The extent of milfoil stem damage was positively
correlated with weevil densities (monthly sampling).
However, weevil densities and stem damage were lower during
1995 (when milfoil biomass was in decline) than during
1996-98 (when milfoil biomass was fully recovered)
Bleomycin increases neutrophil adhesion to human vascular endothelial cells independently of upregulation of ICAM-1 and E-selectin
© 2016 Taylor & Francis. Aim of the Study: Bleomycin-induced lung disease is a serious complication of therapy characterized by alveolar injury, cytokine release, inflammatory cell recruitment, and eventually pulmonary fibrosis. The mechanisms underlying bleomycin-induced pulmonary fibrosis may be relevant to other progressive scarring diseases of the lungs. Pulmonary vascular endothelial cells are critically involved in immune cell extravasation at sites of injury through adhesion molecule expression and cytokine release. We sought to determine the effects of bleomycin on adhesion molecule expression and cytokine release by pulmonary vascular endothelial cells, and their functional relevance to inflammatory cell recruitment. Materials and Methods: The effects of pharmacologically relevant concentrations of bleomycin on adhesion molecule expression and cytokine release by human vascular endothelial cells in vitro were studied by flow cytometry, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay. A flow chamber model was used to assess the functional consequences on adhesion of flowing human neutrophils to endothelial cell monolayers. Results: Bleomycin increased intercellular adhesion molecule 1 (ICAM-1; CD54), vascular cell adhesion molecule (VCAM-1; CD106), and E-selectin (CD62E) expression, and increased monocyte chemoattractant protein (MCP-1) and interleukin (IL-8) release by endothelial cells. Increases in protein expression were accompanied by increased mRNA transcription. In contrast, there was no direct effect of bleomycin on the profibrotic cytokines transforming growth factor-beta (TGF-β), platelet-derived growth factor-BB (PDGF-BB), or endothelin-1. Under flow conditions, endothelial cells exposed to bleomycin supported increased neutrophil adhesion which was independent of ICAM-1 or E-selectin. Conclusion: Our findings demonstrate that bleomycin promotes endothelial-mediated inflammation and neutrophil adhesion. These mechanisms may contribute to the development of pulmonary fibrosis by supporting immune cell recruitment in the lungs
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Process Evaluation of a Peer-Driven, HIV Stigma Reduction and HIV Testing Intervention in Latino and African American Churches.
Purpose: Faith-based organizations may be effective in addressing HIV-related disparities, but few interventions have been implemented across diverse churches. The Facilitating Awareness to Increase Testing for HIV (FAITH) intervention harnessed peer leadership to decrease HIV stigma and promote HIV testing in African American and Latino congregations. A pilot study found more consistent effects among Latino congregations. This process evaluation evaluates implementation of FAITH to better understand the pilot study's findings. Methods: Data sources included HIV education and peer leader workshop evaluation forms, participant views of the community's perspective of HIV, and peer leader follow-up interviews. Data were triangulated with systematic observation notes and analyzed using process-related themes of recruitment, reach, context, implementation, dose-delivered, and fidelity. Results: At the Latino churches (compared to the African American church), facilitators spent more time addressing community-based misconceptions about HIV. The peer leader model was well received, especially among Latino participants, and most said that after the workshop they felt comfortable speaking with others about HIV-related topics. Latino peer leaders reported speaking with up to 20 people within their social networks (particularly with family members); African Americans reported up to 4. Implementation challenges at the African American church may have contributed to the limited intervention effects. Nevertheless, we found the peer motivator model feasible and acceptable across diverse faith settings. Conclusion: Peer-based models within faith settings are promising for addressing HIV. However, differences among groups in HIV knowledge, social network characteristics and norms, and church preferences may influence overall effectiveness
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