23 research outputs found

    Oviducal Sperm Storage in Turkeys: Spatial Distribution of Sperm Within the Uterovaginal Junction Sperm-Storage Tubules

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    The spatial distribution of sperm within the sperm storage tubules (SST) found inthe uterovaginal junction (UVJ) of the turkey is not known. In this study, we inseminated sperm stained with a fluorescent dye (Hoechst 33342) to determine their distribution in SST in the ventral, dorsal, and lateral regions of the proximal, middle, and distal regions of the UVJ. There was no preferential filling in the ventral-dorsal axis of the UVJ. In contrast, preferential filling of the SST was observed in the middle section of the UVJ. Here the individual SST were clearly longer and more pleomorphic than the SST in the more proximal and distal aspects of the UVJ. While no information on the temporal aspect of SST filling by sperm could be gleaned, it is evident that the more morphologically developed SST either accept sperm more readily or store sperm more efficiently than SST elsewhere in the UVJ

    Annual and Seasonal Changes in Parasitism Rates by Hadronotus Pennsylvanicus (Hymenoptera: Scelionidae) on the Squash Bug Anasa Tristis (Hemiptera: Coreidae) in Squash Fields: Implications for Augmentative Releases

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    This study evaluated parasitism rates by Hadronotus pennsylvanicus (Ashmead) (Hymenoptera: Scelionidae) on the squash bug Anasa tristis DeGeer (Hemiptera: Coreidae) over a six-year period in squash fields in Maryland. From 2016–2021, 2226 wild squash bug egg masses were collected, 2180 (98.0%) A. tristis egg masses and 46 (2.0%) A. armigera egg masses. The mean (±SE) parasitism rate was 10.9 ± 0.16%. Yearly parasitism rates were significantly different with rates in 2017 and 2018 that were significantly lower than in 2019, 2020, and 2021. The significant difference in parasitism rates based on planting date was primarily due to the high parasitism rate observed in 2021. These results suggest that the use of augmentative releases early in the season could result in effective control by increasing parasitism earlier in the season and by causing the parasitism rate in the field to peak at a higher number late in the season

    Minimum Concentrations of Slow Pyrolysis Paper and Walnut Hull Cyclone Biochars Needed to Inactivate Escherichia coli O157:H7 in Soil

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    Antimicrobial properties of biochar have been attributed to its ability to inactivate foodborne pathogens in soil, to varying degrees. High concentrations of biochar have reduced E. coli O157:H7 in soil and dairy manure compost, based on alkaline pH. Preliminary studies evaluating 31 different biochars determined that two slow pyrolysis biochars (paper biochar and walnut hull cyclone biochar) were the most effective at inactivating E. coli in soil. A study was conducted to determine the lowest percentages of paper and walnut hull cyclone biochars needed to reduce E. coli O157:H7 in soil. A model soil was adjusted to 17.75% moisture, and the two types of biochar were added at concentrations of 1.0, 1.5, 2.0, 2.5, 3.5, 4.5, 5.5, and 6.5%. Nontoxigenic E. coli O157:H7 were inoculated into soil at 6.84 log CFU/g and stored for up to 6 weeks at 21°C. Mean E. coli O157:H7 counts were 6.01–6.86 log CFU/g at all weeks between 1 and 6 in soil-only positive control samples. Populations in all soil amended with 1.0 and 1.5% of either type of biochar (as well as 2.0% of the walnut hull biochar) resulted in ≤0.68 log reductions at week 6, when compared with positive controls. All other concentrations (i.e., ≥2.0% paper and ≥2.5% walnut hull) inactivated ≥2.7 log at all weeks between 1 and 6 (p < 0.05). At the end of 6 weeks, E. coli O157:H7 declined by 2.84 log in 2.0% paper biochar samples, while concentrations of between 2.5 and 6.5% paper biochar completely inactivated E. coli O157:H7, as determined by spiral plating, at weeks 5 and 6. In contrast, 2.0% walnut hull biochar lowered populations by only 0.38 log at week 6, although 2.5–6.5% concentrations of walnut hull biochar resulted in complete inactivation at all weeks between 3 and 6, as assessed by spiral plating. In summary, ≥2.5% paper or walnut hull biochar reduced ≥5.0 log of E. coli O157:H7 during the 6-week storage period, which we attribute to high soil alkalinity. Amended at a 2.5% concentration, the pH of soil with paper or walnut hull biochar was 10.67 and 10.06, respectively. Results from this study may assist growers in the use of alkaline biochar for inactivating E. coli O157:H7 in soil

    Functional Development of the Octenol Response in Aedes aegypti

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    Attraction of female Aedes aegypti mosquitoes to 1-octen-3-ol (octenol), CO(2), lactic acid, or ammonia emitted by vertebrate hosts is not only contingent on the presence of odorants in the environment, but is also influenced by the insect’s physiological state. For anautogenous mosquito species, like A. aegypti, newly emerged adult females neither respond to host odors nor engage in blood-feeding; the bases for these behaviors are poorly understood. Here we investigated detection of two components of an attractant blend emitted by vertebrate hosts, octenol, and CO(2), by female A. aegypti mosquitoes using electrophysiological, behavioral, and molecular approaches. An increase in sensitivity of octenol olfactory receptor neurons (ORNs) was correlated with an increase in odorant receptor gene (Or) expression and octenol-mediated attractive behavior from day 1 to day 6 post-emergence. While the sensitivity of octenol ORNs was maintained through day 10, behavioral responses to octenol decreased as did the ability of females to discriminate between octenol and octenol + CO(2). Our results show differing age-related roles for the peripheral receptors for octenol and higher order neural processing in the behavior of female mosquitoes

    Dynamic changes in the physicochemical properties of fresh-cut produce wash water as impacted by commodity type and processing conditions.

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    Organic materials in fresh-cut produce wash water deplete free chlorine that is required to prevent pathogen survival and cross-contamination. This research evaluated water quality parameters frequently used to describe organic load for their fitness to predict chlorine demand (CLD) and chemical oxygen demand (COD), which are major needs identified by the industry-led produce food safety taskforce. Batches of romaine lettuce, iceberg lettuce, or carrot of different cut sizes and shapes were washed in 40 liters of water. Physicochemical properties of wash water including CLD, COD, total organic carbon (TOC), total suspended solids (TSS), total dissolved solids (TDS), turbidity, total sugar content, and pH, were monitored. Results indicate that pH is primarily commodity dependent, while organic load is additionally impacted by cutting and washing conditions. Significant linear increases in COD, TOC, CLD, TDS, and turbidity resulted from increasing product-to-water ratio, and decreasing cut size. Physicochemical parameters, excluding pH, showed significant positive correlation across different cut sizes within a commodity. High correlations were obtained between CLD and COD and between COD and TOC for pooled products. The convenient measurement of TDS, along with its strong correlation with COD and CLD, suggests the potential of TDS for predicting organic load and chlorine reactivity. Finally, the potential application and limitation of the proposed models in practical produce processing procedures are discussed extensively

    LT 25

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    Flavanol-Rich Cocoa Powder Interacts with Lactobacillus rhamnossus LGG to Alter the Antibody Response to Infection with the Parasitic Nematode Ascaris suum

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    Consumption of the probiotic bacteria Lactobacillus rhamnosus LGG and flavanol-rich cocoa have purported immune modulating effects. This study compared the host response to infection with Ascaris suum in three-month-old pigs fed a standard growth diet supplemented with a vehicle control: LGG, cocoa powder (CP) or LGG + CP. Pigs were inoculated with infective A. suum eggs during Week 5 of dietary treatment and euthanized 17 days later. Lactobacillus abundance was increased in pigs fed LGG or LGG + CP. Specific anti-A. suum IgG2 antibodies were decreased (p &lt; 0.05) in LGG + CP-fed pigs compared to pigs fed CP alone. Pigs fed LGG had significantly reduced expression (p &lt; 0.05) of Eosinophil peroxidase (EPX), Interleukin 13 (IL-13), Eotaxin 3 (CCL26), Toll-like receptor 2 (TLR2), TLR4, and TLR9 and Interleukin-1Beta (IL1B) in the tracheal-bronchial lymph node (TBLN) independent of CP treatment. These results suggested that feeding LGG significantly reduced the localized prototypical Th2-related markers of infection with A. suum in the TBLN. Although feeding CP does not appear to affect the A. suum-induced Th2-associated cytokine response, feeding LGG + CP reduced anti-A. suum antibodies and delayed intestinal expulsion of parasitic larvae from the intestine

    Viability of Listeria monocytogenes and Salmonella spp. on Slices of a German-Style Bologna Containing Blends of Organic Acid Salts During Storage at 4 or 12°C

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    Viability of cells of Listeria monocytogenes or Salmonella spp. was quantified on slices of a German-style bologna manufactured by a local butcher to contain no added antimicrobials or to include 0.9% or 1.3% of a blend of potassium acetate and sodium diacetate (K-Ace) or 2.5% of a blend of potassium lactate and sodium diacetate (K-Lac) as ingredients. After slicing (ca. 7.1 cm L by 6.7 cm W, ca. 0.5 cm thick, ca. 22.4 g each), a single slice of bologna was placed into a nylon–polyethylene bag and surface inoculated with 250 µL per side of a five-strain mixture of either cells of L. monocytogenes or Salmonella spp. to achieve an initial level of ca. 3.5–4.0 log CFU/slice. The packages were vacuum-sealed and then stored at 4 or 12°C for 90 and 30 days, respectively. Without antimicrobials added to the formulation, L. monocytogenes numbers increased by ca. 5.4 and 6.0 log CFU/slice at both 4 and 12°C during the entire 90- and 30-day storage period, respectively. Likewise, levels of Salmonella also increased by ca. 6.0 log CFU/slice at 12°C in the absence of added antimicrobials; however, levels of this pathogen decreased by ca. 1.7 log CFU/slice after 90 days at 4°C. With the inclusion of 0.9% or 1.3% K-Ace or 2.5% K-Lac in the bologna formulation, levels of L. monocytogenes decreased by ca. ≤0.7 log CFU/slice after 90 days at 4°C, whereas levels of Salmonella decreased by ca. 1.6–2.3 log CFU/slice. After 30 days at 12°C, levels of L. monocytogenes increased by ca. ≤3.4 log CFU/slice on product containing 0.9% K-Ace or 2.5% K-Lac but remained relatively unchanged on slices formulated with 1.3% K-Ace. For Salmonella, in the presence of 0.9% or 1.3% K-Ace or 2.5% K-Lac, pathogen levels decreased by ca. ≤0.7 log CFU/slice at 12°C after 30 days. Our data validate that the inclusion of K-Ace (0.9% or 1.3%) or K-Lac (2.5%) as ingredients is effective for controlling L. monocytogenes and Salmonella on slices of bologna during refrigerated storage
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