226 research outputs found

    Effect of Modification of the NI Artificial Diet on the Biological Fitness Parameters of Mass Reared Western Tarnished Plant Bug, Lygus hesperus

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    The NI artificial diet is the only known successful diet for mass rearing the western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae). This diet has been used for more than a decade. However, because it contains cooked chicken egg, and thus requires laborious preparation (Cohen 2000), this diet is difficult to use. Three modifications (D1, D2, D3) of the NI diet were investigated in hopes of developing a more easily prepared diet that avoids the cooked egg and improves mass fitness parameters of L. hesperus. The modified D3 diet, containing autoclaved chicken egg yolk based component, had the highest egg/cage/day production (13120 ± 812 SE). This was significantly greater than diets D1, containing autoclaved dry chicken egg yolk based component (9027 ± 811 SE), D2, containing autoclaved chicken egg white based component (8311 ± 628 SE), and NI, which contained autoclaved chicken egg yolk + cooked egg diet (7890 ± 761 SE). Significant differences were observed in the weights of all developmental stages except for eggs and first instar nymphs. Higher rates of fertility, hatchability, and low mortality in nymphs during the first instar were also obtained in the modified D3 diet. The results clearly indicated that the D3 diet provided an opportunity to significantly reduce rearing cost by avoiding time-consuming issues with preparation of a cooked egg diet. This should result in an increase in production capacity and a reduction in production costs

    Distinct effects of lexical and semantic competition during picture naming in younger adults, older adults, and people with aphasia

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    Producing a word requires selecting among a set of similar alternatives. When many semantically related items become activated, the difficulty of the selection process is increased. Experiment 1 tested naming of items with either multiple synonymous labels (Alternate Names, e.g., gift/present) or closely semantically related but non-equivalent responses (Near Semantic Neighbors, e.g., jam/jelly). Picture naming was fastest and most accurate for pictures with only one label (High Name Agreement), slower and less accurate in the Alternate Names condition, and slowest and least accurate in the Near Semantic Neighbors condition. These results suggest that selection mechanisms in picture naming operate at two distinct levels of processing: selecting between similar but non-equivalent names requires two selection processes (semantic and lexical), whereas selecting among equivalent names only requires one selection at the lexical level. Experiment 2 examined how these selection mechanisms are affected by normal aging and found that older adults had significantly more difficulty in the Near Semantic Neighbors condition, but not in the Alternate Names condition. This suggests that aging affects semantic processing and selection more strongly than it affects lexical selection. Experiment 3 examined the role of the left inferior frontal gyrus (LIFG) in these selection processes by testing individuals with aphasia secondary to stroke lesions that either affected the LIFG or spared it. Surprisingly, there was no interaction between condition and lesion group: the presence of LIFG damage was not associated with substantively worse naming performance for pictures with multiple acceptable labels. These results are not consistent with a simple view of LIFG as the locus of lexical selection and suggest a more nuanced view of the neural basis of lexical and semantic selection

    Pdx1 and Ngn3 Overexpression Enhances Pancreatic Differentiation of Mouse ES Cell-Derived Endoderm Population

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    In order to define the molecular mechanisms regulating the specification and differentiation of pancreatic β-islet cells, we investigated the effect of upregulating Pdx1 and Ngn3 during the differentiation of the β-islet-like cells from murine embryonic stem (ES) cell-derived activin induced-endoderm. Induced overexpression of Pdx1 resulted in a significant upregulation of insulin (Ins1 and Ins2), and other pancreas-related genes. To enhance the developmental progression from the pancreatic bud to the formation of the endocrine lineages, we induced the overexpression express of Ngn3 together with Pdx1. This combination dramatically increased the level and timing of maximal Ins1 mRNA expression to approximately 100% of that found in the βTC6 insulinoma cell line. Insulin protein and C-peptide expression was confirmed by immunohistochemistry staining. These inductive effects were restricted to c-kit+ endoderm enriched EB-derived populations suggesting that Pdx1/Ngn3 functions after the specification of pancreatic endoderm. Although insulin secretion was stimulated by various insulin secretagogues, these cells had only limited glucose response. Microarray analysis was used to evaluate the expression of a broad spectrum of pancreatic endocrine cell-related genes as well as genes associated with glucose responses. Taken together, these findings demonstrate the utility of manipulating Pdx1 and Ngn3 expression in a stage-specific manner as an important new strategy for the efficient generation of functionally immature insulin-producing β-islet cells from ES cells

    Increasing Protein at the Expense of Carbohydrate in the Diet Down-Regulates Glucose Utilization as Glucose Sparing Effect in Rats

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    High protein (HP) diet could serve as a good strategy against obesity, provoking the changes in energy metabolic pathways. However, those modifications differ during a dietary adaptation. To better understand the mechanisms involved in effect of high protein diet (HP) on limiting adiposity in rats we studied in parallel the gene expression of enzymes involved in protein and energy metabolism and the profiles of nutrients oxidation. Eighty male Wistar rats were fed a normal protein diet (NP, 14% of protein) for one week, then either maintained on NP diet or assigned to a HP diet (50% of protein) for 1, 3, 6 and 14 days. mRNA levels of genes involved in carbohydrate and lipid metabolism were measured in liver, adipose tissues, kidney and muscles by real time PCR. Energy expenditure (EE) and substrate oxidation were measured by indirect calorimetry. Liver glycogen and plasma glucose and hormones were assayed. In liver, HP feeding 1) decreased mRNA encoding glycolysis enzymes (GK, L-PK) and lipogenesis enzymes(ACC, FAS), 2) increased mRNA encoding gluconeogenesis enzymes (PEPCK), 3) first lowered, then restored mRNA encoding glycogen synthesis enzyme (GS), 4) did not change mRNA encoding β-oxidation enzymes (CPT1, ACOX1, βHAD). Few changes were seen in other organs. In parallel, indirect calorimetry confirmed that following HP feeding, glucose oxidation was reduced and fat oxidation was stable, except during the 1st day of adaptation where lipid oxidation was increased. Finally, this study showed that plasma insulin was lowered and hepatic glucose uptake was decreased. Taken together, these results demonstrate that following HP feeding, CHO utilization was increased above the increase in carbohydrate intake while lipogenesis was decreased thus giving a potential explanation for the fat lowering effect of HP diets

    Effects of age on goal-dependent modulation of episodic memory retrieval

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    Retrieval gating refers to the ability to modulate the retrieval of features of a single memory episode according to behavioral goals. Recent findings demonstrate that younger adults engage retrieval gating by attenuating the representation of task-irrelevant features of an episode. Here, we examine whether retrieval gating varies with age. Younger and older adults incidentally encoded words superimposed over scenes or scrambled backgrounds that were displayed in one of three spatial locations. Participants subsequently underwent fMRI as they completed two memory tasks: the background task, which tested memory for the word's background, and the location task, testing memory for the word's location. Employing univariate and multivariate approaches, we demonstrated that younger, but not older adults, exhibited attenuated reinstatement of scene information when it was goal-irrelevant (during the location task). Additionally, in younger adults only, the strength of scene reinstatement in the parahippocampal place area during the background task was related to item and source memory performance. Together, these findings point to an age-related decline in the ability to engage retrieval gating

    Type 2 diabetes – an autoinflammatory disease driven by metabolic stress

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    Type 2 diabetes has traditionally been viewed as a metabolic disorder characterised by chronic high glucose levels, insulin resistance, and declining insulin secretion from the pancreas. Modern lifestyle, with abundant nutrient supply and reduced physical activity, has resulted in dramatic increases in the rates of obesity-associated disease conditions, including diabetes. The associated excess of nutrients induces a state of systemic low-grade chronic inflammation that results from production and secretion of inflammatory mediators from the expanded pool of activated adipocytes. Here, we review the mechanisms by which obesity induces adipose tissue dysregulation, detailing the roles of adipose tissue secreted factors and their action upon other cells and tissues central to glucose homeostasis and type 2 diabetes. Furthermore, given the emerging importance of adipokines, cytokines and chemokines in disease progression, we suggest that type 2 diabetes should now be viewed as an autoinflammatory disease, albeit one that is driven by metabolic dysregulation

    Distribution of the Tarnished Plant Bug (Heteroptera: Miridae) Within Cotton Plants

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    The within-plant distribution of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), in cotton, Gossypium hirsutum L., was determined during June through the 1st week in August in 1992 and 1993 at Stoneville, MS. Locations of adults and nymphs in cotton were determined weekly using visual searches of whole plants or plant sections (mainstem terminals, upper and lower plant halves below the mainstem terminals). The distributions of adults and nymphs found in the morning (0900-1100 hours) in 1992 were not significantly different from their distributions found in the afternoon (1300-1500 hours). Adults had a significantly different distribution than nymphs on vegetative structures (mainly leaves), fruiting structures (squares, bolls, and blooms) and mainstem terminals in both years. The distributions of adults and nymphs also were significantly different in both years on the mainstem terminals and upper and lower plant halves below the terminal. Nymphs and adults were found in both years to have 75% of their populations (on average) in the mainstem terminal plus the fruit and vegetative structures on the top 6 nodes of the plant. Nymphs showed a strong preference for fruiting structures, and high percentages of adults were found on vegetative structures through the first 3 wk of squaring (June through the 1st week in July) in both years. Adults then became more dispersed among the vegetative structures, fruit, and mainstem terminals. These types of distributions would make the drop cloth an excellent method for sampling nymphs, whereas the sweep net would work well for adults especially through the first 3 wk of squaring. If visual examination of plants for nymphs and adults is used to sample cotton, it should include mainstem terminals plus vegetative and fruiting structures in the upper halves of plants

    Visit on Thursday 18 July 2019 to Glendower Farm, Beacon and Barville Park

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    The hill on which stands the Glendower Beacon, built on the 1877 recommendation of harbour engineer Sir John Coode. The 15 metre-high structure has benefitted passing vessels and aircraft ever since, but the view from there for our group of 72 Lower Albany Historical Society members on Thursday 18/7/19 was purely food for the soul.</jats:p
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