Natural killer cells as an initial defense against pathogens.

Natural killer (NK) cells serve as a crucial first line of defense against tumors and a diverse range of pathogens. Recognition of infection by NK cells is accomplished by the activation of receptors on the NK cell surface, which initiate NK cell effector functions. Many of the receptors and ligands involved in NK cell antimicrobial activity have been identified, and we are beginning to appreciate how they function during infection. In addition, NK cells are activated by cytokines (e.g. interleukin 12 and type I interferons), which are products of activated macrophages and dendritic cells. In response to these activating stimuli, NK cells secrete cytokines and chemokines and lyse target cells. Recent studies have focused on the mechanisms by which NK cells recognize and respond to viruses, parasites and bacteria, and on the unique role of NK cells in innate immunity to infection

Increasing Low-income Residents’ Access to Fresh Produce through a Local Mobile Pantry

Seeds that Feed (STF) is a mobile food pantry located in Fayetteville, Arkansas. STF receives produce from local farmers to distribute to residents in low-income housing sites throughout Northwest Arkansas. According to Feeding America, food insecurity affected 14.3% Washington County, Arkansas’ population in 2016. The purpose of this study was to determine if STF’s model is an effective way to increase individuals’ access to fresh fruits and vegetables and increase their potential to meet the United States Department of Agriculture’s Food Patterns (USDA-FP) for to fruit and vegetable consumption. Twenty-three participants from three sites completed the study. A survey was used to collect basic demographics and dietary patterns. Record was taken of what foods each participant received on the survey day including plans for preparation and to whom it would be served. All anonymous responses were statistically analyzed using Excel. The results indicated that the likelihood to meet the USDA-FP for overall fruit and vegetable intake increased significantly after receiving approximately one cup of fruit and 1 ½ cups of vegetables from STF. A positive correlation was found between the number of times participants received produce from STF and participant’s total fruit intake and total intake of the “red/orange” and “other” vegetable subgroups. Therefore, STF’s model appears to be an effective method to increase access to fresh produce. Future research could utilize STF’s model to assess the potential for other supplemental nutrition programs to help low-income residents meet the USDA-FP and reduce food insecurity via mobile pantry

INTERACTIONS OF HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS WITH TOBACCO TREATED STREPTOCOCCUS MUTANS

poster abstractStreptococcus mutans and tobacco are risk factors for atherosclerosis. The objective of this study was to determine the ability that a spaP isogenic defective mutant of S. mutans UA 159 has on binding to Human Umbilical Vein Endothelial Cells (HUVEC) when treated with tobacco products and what second messenger signals are involved. The study was conducted to examine the effects that various concentrations of cigarette smoke condensate (CSC)- and nicotine have on S. mutans cell cytotoxicity and expression of cytokines and growth factors from HUVECs. S. mutans was grown at 37°C and planktonic and biofilm cells were separated from the culture supernatant. The supernatant was discarded the cells were washed, sterilized with formaldehyde and washed again to remove the formaldehyde. The concentrations of the various S. mutans cells were standardized to the same concentration (absorbance of 0.50 ± 0.01) by spectroscopy at a wavelength of 600 nm. The lowest non-toxic levels of the sterilized bacterial cells were used to treat HUVECs for 72 hours and cytotoxicity was determined by lactate dehydrogenase (LDH) assays. The cytokine/growth factor expression will be determined by antibody protein arrays. The results are expected to indicate an increase in cytotoxicity with increasing cell concentrations, along with increased pro-inflammatory cytokine/growth factors expression by the HUVECs treated with tobacco treated S. mutans compared to S. mutans that was not treated with tobacco products. Second messenger signaling pathways will be analyzed with ERK and JNK inhibitors and specific antibodies to ERK and phospho-JNK. Immunoblots using HUVECs will be done to determine expression of ERK/JNK. A better understanding of the detrimental effects that tobacco has on the underlining causes of atherosclerosis can advance the quest of controlling the disease

Homeostatic Control of Memory Cell Progenitors in the Natural Killer Cell Lineage

SummaryRecent studies have demonstrated that natural killer (NK) cells are able to undergo clonal expansion and contraction and to generate self-renewing memory cells after infection with mouse cytomegalovirus (MCMV). It is unclear whether all or only certain subsets preferentially contribute to the generation of memory NK cells. Here, we show that memory NK cells predominantly arise from killer cell lectin-like receptor G1 (KLRG1)-negative NK cell progenitors, whereas KLRG1-positive NK cells have limited capacity for expansion during infection with MCMV. Unexpectedly, the frequency of KLRG1-positive NK cells is significantly affected by the presence of T cells in the host and potentially by the host microbiota. Our findings demonstrate that excessive availability of interleukin (IL)-15 may erode the pool of memory progenitors, resulting in the decreased efficiency of memory generation in the NK cell lineage

Increasing Profitability of Small Scale Orchard Producers through Optimizing Replacement Rate: The Case Study of Ghana

This study sets out to empirically estimate the optimum annual replacement rate and age of cocoa trees in order to maximize the net present value of four common cocoa production systems. The study examines the costs and returns of four common cocoa production systems in Ghana associated with changes in cocoa prices, fertilizer prices, inflation rates, and labor prices. While this study focuses on cocoa, the methodology is applicable to any perennial crop. This study uses empirical yield curves and cost of production data from Ghana to determine when and what percentage of a cocoa orchard should be replaced annually to maximize net present value of revenues over time. Successive versions of the model are solved to determine how input and output price changes affect optimal replacement rates and replacement ages. Producers in both high- and low-income countries are reluctant to cull still productive assets, such as trees that are diminishing in yield over time. The Excel based model developed in this study could provide extension personnel with a simple yet powerful tool to illustrate to producers the benefits of systematic tree replacement. This study provides strong evidence of the benefits of replacing trees at the optimal time and rate.Cocoa, Replacement Rate, Net Present Value (NPV), Production Economics, Q01, Q15, Q32,

Willingness-to-Pay for Halal and Branded Poultry in Northern Mozambique

While price typically drives consumers’ food-purchasing decisions in low-income countries, religious attributes associated with food production and corporate branding could influence buying patterns. In Mozambique, more than 46% of people were living below the poverty line of ($0.31 USD) per day in 2018. That being said, in the Nampula Province (the location of this study), which is the second poorest province in the country, over 25% of the population is Muslim and may be willing-to-pay (WTP) a premium for Halal meat products to uphold Islamic beliefs. Like many parts of sub-Saharan Africa, poultry is the fastest-growing source of protein. Since large-scale domestic poultry industries are relatively new in Mozambique, brand loyalty is a new concept that has not been empirically analyzed before in the literature. In this study, we surveyed 312 consumers in Nampula, Mozambique, using a choice-based modeling approach to estimate if consumers were WTP for chicken that was slaughtered according to Halal laws and chicken which was branded by New Horizons (the largest chicken producer in Nampula). Results from the small sample in this study indicated that even in low-income countries like Mozambique, consumers are WTP a premium for branding. Specifically, Muslim consumers were WTP a premium for Halal-produced meat with branding. While non-Muslims did associate Halal poultry with being safer (69%) and of better quality (64%), but they were not found to be WTP a premium for these attributes

Interleukin 2 activation of natural killer cells rapidly induces the expression and phosphorylation of the Leu-23 activation antigen.

IL-2 potentiates both growth and cytotoxic function of T lymphocytes and NK cells. Resting peripheral blood NK cells can respond directly to rIL-2, without requirement for accessory cells or cofactors, and enhanced cytotoxicity can be measured within a few hours after exposure to this lymphokine. In this study, we describe an activation antigen, Leu-23, that is rapidly induced and phosphorylated after IL-2 stimulation of NK cells and a subset of low buoyant density T lymphocytes. Previously, it has been uncertain whether all NK cells or only a subset are responsive to IL-2. Since within 18 h after exposure to IL-2, essentially all NK cells express Leu-23, these findings indicate that all peripheral blood NK cells are responsive to stimulation by IL-2. The Leu-23 antigen is a disulfide-bonded homodimer, composed of 24-kD protein subunits with two N-linked oligosaccharides. Appearance of this glycoprotein on NK cells is IL-2 dependent and closely parallels IL-2-induced cytotoxicity against NK-resistant solid tumor cell targets