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Radical S-adenosylmethionine (SAM) enzymes in cofactor biosynthesis: A treasure trove of complex organic radical rearrangement reactions
No full textIn this minireview, we describe the radical S-adenosylmethionine enzymes involved in the biosynthesis of thiamin, menaquinone, molybdopterin, coenzyme F420, and heme. Our focus is on the remarkably complex organic rearrangements involved, many of which have no precedent in organic or biological chemistry
Perinatal maternal probiotic intervention impacts immune responses and ileal mucin gene expression in a rat model of irritable bowel syndrome
No full textAlterations in immune responses and intestinal secretory state are among features commonly observed in the maternal separation (MS) rat model of Irritable Bowel Syndrome. This study examined whether perinatal maternal introduction of probiotics influences plasma immune markers and ileal mucin-2 (MUC2) gene expression in rat offspring exposed to neonatal maternal separation (MS, 3 h/day, postnatal days (PND) 2-14) and/or subsequently to acute restraint stress in adulthood (AS, 30 min/day, PND 83-85). Data analysis indicated that stress protocols did not affect plasma tumour necrosis factor alpha (TNF-α), interferon gamma (IFN-γ) and interleukin (IL)-6 levels in young offspring (PND 24) born to the vehicle-treated dams. Maternal probiotic intervention was associated with significantly decreased IFN-γ levels in young offspring compared with non-probiotic offspring (P≤0.05). It also induced a significant increase in IL-6 levels in MS pups (P≤0.05). Exposure of both non-MS and MS offspring to AS induced a significant increase in haptoglobin levels compared to controls (P≤0.05), whereas all offspring born to the probiotic-treated dams, irrespective of stress treatment conditions, exhibited significantly decreased haptoglobin levels to well below the control levels (P≤0.05). MS and/or AS did not affect ileal expression of MUC2 in offspring born to the non-probiotic treated dams. While maternal probiotic intake significantly downregulated ileal gene expression of MUC2 in MS male young offspring, it was associated with significantly upregulated MUC2 mRNA expression in MS or AS adult male offspring. These findings suggest that maternal probiotic intervention may exert long-lasting anti-inflammatory effects and impact gut outcomes in offspring at increased risk of dysfunctional gut
Robust switching output feedback control of discrete-time linear polytopic uncertain systems
No full textThis paper presents a new switching control approach for robust output feedback control of a class of discrete-time linear systems subject to polytopic time-varying uncertainties. The proposed robust switching controller, which stabilizes the closed-loop system with a pre-specified H∞ performance level, consists of a family of dynamic output feedback controllers (of an arbitrary state order) and a switching law (the relaxed min-switching strategy). Both stability analysis and control synthesis conditions are derived using a piecewise quadratic Lyapunov function. The switching law combined with the controller gain matrices are jointly synthesized by solving a convex linear matrix inequality (LMI) based optimization problem. An academic example has been used to demonstrate the effectiveness and advantages of the proposed approach
Imported and Domestic Beef: Are They Substitutes or Complements?
No full textThis paper uses a translog processing cost function to test whether imported beef and domestic beef are substitutes or complements. Findings suggest that imported beef and domestic beef are substitutes, thus giving grounds to the claim by U.S. cattle producers that beef imports decrease the use of domestic beef. The effect of a price decline of beef imports has more pronounced effect on the use of cull cow beef than carcass beef, with the latter dropping by more than three times the former during the sample period
Photosynthetic leaf area modulates tiller bud outgrowth in sorghum
No full textShoot branches or tillers develop from axillary buds. The dormancy versus outgrowth fates of buds depends on genetic, environmental and hormonal signals. Defoliation inhibits bud outgrowth indicating the role of leaf-derived metabolic factors such as sucrose in bud outgrowth. In this study, the sensitivity of bud outgrowth to selective defoliation was investigated. At 6d after planting (6 DAP), the first two leaves of sorghum were fully expanded and the third was partially emerged. Therefore, the leaves were selectively defoliated at 6 DAP and the length of the bud in the first leaf axil was measured at 8 DAP. Bud outgrowth was inhibited by defoliation of only 2cm from the tip of the second leaf blade. The expression of dormancy and sucrose-starvation marker genes was up-regulated and cell cycle and sucrose-inducible genes was down-regulated during the first 24h post-defoliation of the second leaf. At 48h, the expression of these genes was similar to controls as the defoliated plant recovers. Our results demonstrate that small changes in photosynthetic leaf area affect the propensity of tiller buds for outgrowth. Therefore, variation in leaf area and photosynthetic activity should be included when integrating sucrose into models of shoot branching
Perinatal maternal probiotic intervention impacts immune responses and ileal mucin gene expression in a rat model of irritable bowel syndrome
No full textAlterations in immune responses and intestinal secretory state are among features commonly observed in the maternal separation (MS) rat model of Irritable Bowel Syndrome. This study examined whether perinatal maternal introduction of probiotics influences plasma immune markers and ileal mucin-2 (MUC2) gene expression in rat offspring exposed to neonatal maternal separation (MS, 3 h/day, postnatal days (PND) 2-14) and/or subsequently to acute restraint stress in adulthood (AS, 30 min/day, PND 83-85). Data analysis indicated that stress protocols did not affect plasma tumour necrosis factor alpha (TNF-α), interferon gamma (IFN-γ) and interleukin (IL)-6 levels in young offspring (PND 24) born to the vehicle-treated dams. Maternal probiotic intervention was associated with significantly decreased IFN-γ levels in young offspring compared with non-probiotic offspring (P≤0.05). It also induced a significant increase in IL-6 levels in MS pups (P≤0.05). Exposure of both non-MS and MS offspring to AS induced a significant increase in haptoglobin levels compared to controls (P≤0.05), whereas all offspring born to the probiotic-treated dams, irrespective of stress treatment conditions, exhibited significantly decreased haptoglobin levels to well below the control levels (P≤0.05). MS and/or AS did not affect ileal expression of MUC2 in offspring born to the non-probiotic treated dams. While maternal probiotic intake significantly downregulated ileal gene expression of MUC2 in MS male young offspring, it was associated with significantly upregulated MUC2 mRNA expression in MS or AS adult male offspring. These findings suggest that maternal probiotic intervention may exert long-lasting anti-inflammatory effects and impact gut outcomes in offspring at increased risk of dysfunctional gut
Evaluation of antimicrobial activities of sequential spray applications of decontamination treatments on chicken carcasses
No full textThe objective of this study was to evaluate the effects of sequential applications of ε-polylysine (EPL) or lauramide arginine ethyl ester (LAE) sprays followed by an acidic calcium sulfate (ACS) spray on inoculated chicken carcasses to reduce Salmonella (Salmonella enterica serovars including Salmonella typhimurium and Salmonella enteritidis) contamination during 6 days of storage (4.4°C). Secondly, reductions of the resident microflora were studied on uninoculated chicken carcasses following the sequential application of the treatments, chilling and 10 days of storage at 4.4°C. The treatment of Salmonella inoculated carcasses with 300 mg/L EPL followed by 30% ACS (EPL300-ACS30) sprays reduced Salmonella counts initially by 1.5 log cfu/mL and then by 1.2 log cfu/mL (p\u3c0.05) following 6 days of storage at 4.4°C. Likewise, 200 mg/L LAE followed by 30% ACS (LAE200-ACS30) treatment reduced initial Salmonella counts on poultry carcasses by 1.8, 1.4 and 1.8 log cfu/mL (p\u3c0.05), respectively, after 0, 3, and 6 days storage. Immediately after the treatments, EPL300-ACS30 and LAE200-ACS30 both reduced Escherichia coli counts significantly by 2.6 and 2.9 log cfu/mL, respectively. EPL300-ACS30 and LAE200-ASC30 were effective in lowering psychrotroph counts by 1 log cfu/mL on day 10 when compared to the control and distilled water treatments. This study demonstrated that EPL300-ACS30 and LAE200-ACS30 were effective in reducing Salmonella on inoculated chicken carcasses both after treatment and during the storage at 4.4°C for up to 6 days. In addition, reductions in psychrotroph counts indicated that these treatments might have the potential to increase the shelf-life of poultry carcasses
The relationship between the option-implied volatility smile, stock returns and heterogeneous beliefs
No full textWe study the relationship between stock returns and the implied volatility smile slope of call and put options. Stocks with a steeper put slope earn lower future returns, while stocks with a steeper call slope earn higher future returns. Using dispersion of opinion as a proxy for belief differences, we find that the slope-stock return relation is strongest for stocks with high belief differences. The idiosyncratic component of the put slope fully explains the negative risk-adjusted stock returns. For the call slope, the idiosyncratic component dominates the systematic one, and explains the positive risk-adjusted returns
