Nitrosylation of myoglobin and nitrosation of cysteine by nitrite in a model system simulating meat curing

Demand is growing for meat products cured without the addition of sodium nitrite. Instead of the direct addition of nitrite to meat in formulation, nitrite is supplied by bacterial reduction of natural nitrate often added as vegetable juice/powder. However, the rate of nitrite formation in this process is relatively slow, and the total ingoing nitrite is typically less than in conventional curing processes. The objective of this study was to determine the impact of the rate of addition of nitrite and the amount of nitrite added on nitrosylation/nitrosation reactions in a model meat curing system. Myoglobin was preferentially nitrosylated as no decrease in sulfhydryl groups was found until maximum nitrosylmyoglobin color was achieved. The cysteine-myoglobin model retained more sulfhydryl groups than the cysteine-only model (p < 0.05). The rate of nitrite addition did not alter nitrosylation/nitrosation reactions (p > 0.05). These data suggest that the amount of nitrite but not the rate of addition impacts the nitrosylation/nitrosation reactions this system.     

Vacuolar glyphosate-sequestration correlates with glyphosate resistance in ryegrass (Lolium spp.) from Australia, South America, and Europe: a 31P NMR investigation

Lolium spp., ryegrass, variants from Australia, Brazil, Chile, and Italy showing differing levels of glyphosate resistance were examined by (31)P NMR. Extents of glyphosate (i) resistance (LD(50)), (ii) inhibition of 5-enopyruvyl-shikimate-3-phosphate synthase (EPSPS) activity (IC(50)), and (iii) translocation were quantified for glyphosate-resistant (GR) and glyphosate-sensitive (GS) Lolium multiflorum Lam. variants from Chile and Brazil. For comparison, LD(50) and IC(50) data for Lolium rigidum Gaudin variants from Italy were also analyzed. All variants showed similar cellular uptake of glyphosate by (31)P NMR. All GR variants showed glyphosate sequestration within the cell vacuole, whereas there was minimal or no vacuole sequestration in the GS variants. The extent of vacuole sequestration correlated qualitatively with the level of resistance. Previous (31)P NMR studies of horseweed ( Conyza canadensis (L.) Cronquist) revealed that glyphosate sequestration imparted glyphosate resistance. Data presented herein suggest that glyphosate vacuolar sequestration is strongly contributing, if not the major contributing, resistance mechanism in ryegrass as well.     

Dynamic interactions of natural organic matter and organic compounds

Purpose

This article reviews our current understanding about how organic chemicals and water interact dynamically with, and therefore coevolve with, soil and sediment natural organic matter (NOM). NOM can be regarded as a polymer-like phase that responds to the input of organic compounds in ways analogous to synthetic polymers.

Methods

Sorption selectivity of organic compounds is shown to result in part from the three-dimensional microstructure of NOM related to its glassy character. Sorption to NOM conforms to polymer theory by exhibiting isotherm shape and irreversible behaviors characteristic of the glassy organic physical state. The glassy state is a metastable state characterized by the presence of excess free volume (holes).

Results

In polymers and NOM, incoming molecules preferentially occupy holes due to the absence of a cavitation penalty. Incoming molecules can enlarge existing holes and create new holes that do not relax completely when the molecules leave. The physical changes in NOM induced by sorption result in hysteresis in the isotherm that persists indefinitely at ambient temperature.

Conclusions

Sorption selectivity and hysteresis have important implications for the fate and bioavailability of contaminants.     

Anti-Inflammatory Concentrate Enriched with Substituted Oligofucans Derived from Brown Seaweed Turbinaria conoides (J. Agardh) Kützing and Its Safety Assessment on Wistar Rats

ABSTRACT

Aqueous extract of the seaweed Turbinaria conoides was purified to obtain an oligofucan-enriched seaweed concentrate (OESC). Oligofucans isolated were characterized as two types with (→1)-fucose-(2,3-diSO₃^?)-(1→4)-fucose-(2-SO₃^?)-(1→3)-fucose-(2,3-diSO₃^?)-(1→4)-fucose-(2-SO₃^?, 3-OAc)-(4→) and (→1)-fucose-(3-SO₃^?)-(1→4)-fucose-(2-SO₃^?)-(1→4)-fucose-(3-SO₃^?)-(1→4)-fucose-(2-SO₃^?)-(4→) motifs. A 90-day accelerated shelf-life study (50°C) showed that OESC maintained its antioxidant properties (free radical scavenging, reducing, lipid peroxidation inhibition, and chelating activities) even after 30 days. In vitro COX-2 and 5-LOX inhibitory properties of OESC (67.2 and 95.2%, respectively) showed no significant variation even at the 30th day. OESC significantly mitigated the carrageenan-induced inflammation in rats at 0–2 h (59.7–70.3% inhibition), which were greater compared to the synthetic NSAID aspirin. The safety of OESC has been assessed by acute (14 days) and subchronic (90 days) oral toxicity studies, which showed no toxicity-related significant changes in renal or hepatic function, hematological indices, and serum biochemical parameters in the OESC-treated Wistar rats. No histopathological alterations were observed in the vital organs of rats treated with OESC. LD₅₀ and sub-chronic no-observed-adverse-effect level (NOAEL) for this concentrate were found to be > 5,000 and 2,000?mg/kg BW, respectively. Hence, oligofucan-enriched seaweed concentrate is safe to consume without any adverse effects in the body.     

Antioxidative Status of a Nutrient Enriched Formulation of Perna viridis in a Time Series Shelf-Life Study

ABSTRACT

The freeze-dried concentrate of green mussel, Perna viridis, was added with naturally derived antioxidative oleoresins of rosemary and turmeric along with trace amounts of other natural additives to prepare different treatments and was subjected to accelerated shelf life study (50°C) to evaluate its oxidative stability. The total oxyradical scavenging activities of samples with higher concentrations of turmeric over rosemary demonstrated the prominent role of the turmeric extracts to arrest free radical chain reactions. Time dependent antioxidative status in relation to the nutritional compositions was evaluated to identify the oxidative changes for different treatments. The addition of natural additives with polyphenolic moieties in the treatments shielded the mussel’s unsaturated fatty acids against oxidation as evident by higher polyunsaturated fatty acids in the two treatments as compared to control after 90 days of accelerated shelf-life study. Higher n-3/n-6 ratios after 90 days’ storage were also observed in these treatments. A threshold level of combined turmeric (0.8 g/100 g) and rosemary (0.4 g/100 g) was sufficient for optimum antioxidant activity and to maintain nutritional composition of the green mussel extract at desired levels.     

Combined effects of termiticides and mechanical stress on chlorinated polyvinyl chloride (CPVC) pipe

BACKGROUND: CPVC pipe failures have recently been reported beneath structures as a result of termiticide soil treatments. To determine whether these CPVC failures were actually caused by termiticides, CPVC tubes were filled with 50 mL of either termiticide concentrate, dilutions or treated builder's sand and sealed. Mechanical stress was added to these sealed tubes by hanging bricks from their ends.RESULTS: As concentrates, eight of nine emulsifiable concentrates tested caused failure within 8 weeks. None of the three suspensible concentrates tested caused failure over this period. Dilution of emulsifiable concentrates caused progressively fewer CPVC tube failures. No treated soils caused tube failures. Excessive CPVC glue applications in combination with chlorpyrifos 440 g kg(-1) EC (Dursban(trade mark) TC) degraded the CPVC. All volatile organic compounds (VOCs) found in the termiticide formulations caused CPVC tube failure within 1 week as pure chemicals. The VOC 1,3,5-trimethylbenzene caused CPVC tube failure within minutes of exposure. This VOC was found in all termiticides that caused failures as concentrates.CONCLUSION: It is highly improbable that a properly conducted preconstruction soil treatment, where termiticide is completely adsorbed to the soil, would be solely responsible for CPVC pipe failure. Manufacturers should consider removing 1,3,5-trimethylbenzene from termiticide formulations to minimize the risk of CPVC pipe failure.     

Effect of genotype of cocoa (Theobroma cacao) on attractiveness to the mirid Sahlbergella singularis (Hemiptera: Miridae) in the laboratory

BACKGROUND: Mirids are a major constraint to cocoa growing in Africa. Cocoa breeding for tolerance/resistance could be effective in an integrated pest management system. Attractiveness is one aspect of tolerance/resistance, and decreasing the attractiveness of cocoa trees should be a good way of reducing damage. RESULTS: Small-scale laboratory tests were carried out in Cameroon to assess differences in the attractiveness to mirids of eleven cocoa genotypes. The genotypes were ranked according to their attractiveness score and a distance from a mean value. An analysis of variance was performed and revealed significant differences between cocoa genotypes (F=3.15, P<0.001). The cocoa genotype groupings revealed three major categories, with BE10 and SNK413 proving to be the most attractive. In contrast, five genotypes, IMC60, the Catongo Trinitario genotypes, Playa Alta2 (from Venezuela), SIC5 and SNK614, proved to be less attractive than the mean. Four genotypes (PA107, SNK619, UPA134 and T60/887) displayed similar attractiveness to the mean. CONCLUSION: The circular microtest offered the advantage of not needing a reference cocoa genotype. The least attractive clones, such as IMC60, were also the most tolerant in the field. Comparisons with the results of other studies are proposed.     

Identifying mangrove areas for fisheries enhancement; population assessment in a patchy habitat

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Improvement in nitrogen availability, nitrogen uptake and growth of aerobic rice following soil acidification

A yield decline and increase in soil pH under continuous cropping of aerobic rice have been reported in previous studies. However, the underlying mechanisms governing the poor growth and low yield of aerobic rice following an increase in soil pH are unknown. The objective of the present study was to determine the effect of soil acidification on the soil nutrient availability, plant nutrition and growth of aerobic rice grown in continuously cropped aerobic soil. Two pot experiments were conducted using soil from a field where aerobic rice had been grown for 13 consecutive seasons. Soil was acidified by adding 50–300 mL of 0.05 mol L^–1 sulfuric acid to 3.0 kg of air-dried soil to achieve a range of soil pH levels. Rice was grown aerobically with N rates of 0–1.2 g per pot using urea or ammonium sulfate. Soil chemical properties were measured as were leaf nutrient concentrations, plant growth parameters, and the above-ground N uptake. A 5.5-fold and 1.5-fold increase in soil ammonium and nitrate were observed, respectively, after adding sulfuric acid. Plant growth and N uptake improved significantly with soil acidification, regardless of N rates or N sources, and were associated with an improvement in plant N nutrition. The application of N had greater positive effects on plant growth and N uptake than soil acidification. The growth response to soil acidification reduced as the rate of N application increased. These results suggest that the yield decline of continuous aerobic rice is probably associated with a reduction in soil N availability and plant N uptake as a result of a gradual increase in soil pH.