Modeling the effect of temperature on bioaccumulation of metals by a marine bioindicator organism, Mytilus edulis

To determine whether regional or seasonal variability in water temperatures might affect the bioaccumulation of metals by marine invertebrates, we used a biokinetic/bioenergetic approach to model metal bioaccumulation (Ag, Am, Cd, Co, Se, and Zn) from dietary and dissolved sources by blue mussels, Mytilus edulis, acclimated at 2 and 12 degrees C. Accumulation of metal from the aqueous phase was not affected by temperature. However, Ag, Am, and Zn from diet were respectively accumulated up to 5.7-fold, 5.3-fold, and 2-fold more effectively at 2 degrees C than at 12 degrees C, largely because these three metals were assimilated from food more effectively at the lower temperature. In contrast, bioaccumulation of Cd, Co, Se from diet was not substantially affected by temperature even though efflux constants for these metals were up to 4-fold lower at 2 degrees C than at 12 degrees C. Total bioaccumulation of Ag, Am, and Zn was up to 1.7-3.6-fold higher at 2 degrees C than at 12 degrees C, with the largest differences predicted for high food conditions. Temperature-related variability in bioaccumulation of metals should be considered when interpreting patterns in metal tissue concentrations and when adapting management strategies developed for temperate seas to polar areas.     

Effects of ball‐milling treatment on mussel (Mytilus edulis) protein: structure,functional properties and in vitro digestibility

In this study, the effects of ball‐milling treatment on structural properties and functional properties of mussel protein were investigated. In vitro protein digestibility and free amino acid contents were also evaluated. Ball‐milling treatment did not change the primary structure of mussel protein, but caused changes of secondary structure. The tertiary and quaternary structure also changed. After 20 min of ball‐milling treatment, the whiteness and oil‐binding capability of mussel protein significantly improved from 13.67 to 26.62 and 43.76% to 196.00%, while the protein solubility and water‐holding capability of mussel protein significantly decreased from 74.89% to 53.10% and 215.67% to 90.91%. Ball‐milling treatment increased the in vitro digestibility significantly. These results provide theoretical basis for the utilisation of mussel protein in food industry.     

Studies on the skin uptake and efflux kinetics of N-phenyl-p-phenylenediamine: an aromatic amine intermediate

N-phenyl-p-phenylenediamine (N-PPDA), an industrial intermediate and hair dye ingredient, has been implicated in a variety of toxic symptoms including cutaneous manifestations. However, the role of physiological factors that may determine and modify its absorption and transport within and through the skin is not fully understood. The present study reveals that N-PPDA binds readily to skin showing saturation kinetics with K m and V_max of 2.54 × 10⁻⁴ M and 4.76 μmol g⁻¹ skin, respectively. The uptake was dependent upon the area of skin, concentration of the amine, exposure time, temperature and pH of the vehicle. Heat treatment facilitated the binding but temperatures abouv 50° caused significant lowering of the uptake, indicating the possible involvement of collagen matrix. Skin lipids also contributed in the binding of N-PPDA. Bioinhibitors such as KCN, sodium arsenate, NaF, N-ethylmaleimide, cycloheximide, iodoacetic acid and 2,4-dinitrophenol had no effect on the uptake potential, suggesting it to be a non-energy dependent process. Most of the skin-bound N-PPDA was effluxed through serum proteins reaching the target organs via systemic circulation.     

Invited review: New perspectives on the roles of nutrition and metabolic priorities in the subfertility of high-producing dairy cows

Management, nutrition, production, and genetics are the main reasons for the decline in fertility in the modern dairy cow. Selection for the single trait of milk production with little consideration for traits associated with reproduction in the modern dairy cow has produced an antagonistic relationship between milk yield and reproductive performance. The outcome is a multi-factorial syndrome of subfertility during lactation; thus, to achieve a better understanding and derive a solution, it is necessary to integrate a range of disciplines, including genetics, nutrition, immunology, molecular biology, endocrinology, metabolic and reproductive physiology, and animal welfare. The common theme underlying the process is a link between nutritional and metabolic inputs that support complex interactions between the gonadotropic and somatotropic axes. Multiple hormonal and metabolic signals from the liver, pancreas, muscle, and adipose tissues act on brain centers regulating feed intake, energy balance, and metabolism. Among these signals, glucose, fatty acids, insulin-like growth factor-I, insulin, growth hormone, ghrelin, leptin, and perhaps myostatin appear to play key roles. Many of these factors are affected by changes in the somatotropic axis that are a consequence of, or are needed to support, high milk production. Ovarian tissues also respond directly to metabolic inputs, with consequences for folliculogenesis, steroidogenesis, and the development of the oocyte and embryo. Little doubt exists that appropriate nutritional management before and after calving is essential for successful reproduction. Changes in body composition are related to the processes that lead to ovulation, estrus, and conception. However, better indicators of body composition and measures of critical metabolites are required to form precise nutritional management guidelines to optimize reproductive outcomes.The eventual solution to the reduction in fertility will be a new strategic direction for genetic selection that includes fertility-related traits. However, this will take time to be effective, so, in the short term, we need to gain a greater understanding of the interactions between nutrition and fertility to better manage the issue. A greater understanding of the phenomenon will also provide markers for more targeted genetic selection. This review highlights many fruitful directions for research, aimed at the development of strategies for nutritional management of reproduction in the high-producing subfertile dairy cow.     

煎炸油中总极性物质对细胞抑制和诱导凋亡的影响

研究煎炸油中总极性物质(TPM)对细胞的生长抑制和诱导凋亡。结果表明:1.0mg/m L的TPM作用于Hep G2细胞24、48、72h后,细胞增殖抑制率分别为9.8%、12.6%、16.1%;流式细胞仪结果显示,随着TPM浓度的增加,加药组细胞凋亡率逐渐增加,G0/G1期细胞数目逐渐减少,S期细胞数目逐渐增多,说明TPM对He PG2细胞增殖的抑制发生在S期。     

Atosiban, an oxytocin receptor blocking agent: pharmacokinetics and inhibition of milk ejection in dairy cows

Plasma concentrations of the oxytocin receptor blocking agent Atosiban were measured at 2, 4, 10, 15 and 20 min after injection of 5, 10, 20 and 50 micrograms Atosiban/kg body weight in six dairy cows. The half life of Atosiban was 18 min and the total body clearance was 3301 ml/min. Intramammary pressure (IMP) within the teat cistern was measured in six cows before and after i.v. injection of 0 or 20 micrograms Atosiban/kg body weight and repeated injections of 0.2 or 0.5 i.u. oxytocin. IMP was also measured in eleven cows after injection of 0, 10 or 50 micrograms Atosiban/kg body weight: in seven during oxytocin infusions, in four after oxytocin injections in successively increasing dosages (0.05, 0.1, 0.2, 0.5, 1 and 10 i.u.). The occurrence of milk ejection was indicated by a rise in IMP. After injection of 20 micrograms Atosiban/kg body weight, 0.2 i.u. oxytocin did not induce an IMP rise before 48 min, whereas 0.5 i.u. oxytocin induced an IMP rise within 4 min. The time from the start of infusion until the beginning of the IMP rise and the duration of IMP rise during oxytocin infusions both increased, whereas the IMP rise itself was diminished by increasing Atosiban dosages. The amount of injected oxytocin necessary to induce an IMP response increased with increasing Atosiban dosages. Atosiban was shown to have a powerful effect in inhibiting milk ejection in dairy cows.     

Comparison of acids on the induction of an Acid Tolerance Response in Salmonellatyphimurium, consequences for food safety

Salmonellatyphimurium inactivation at pH 3.0 in Brain Heart Infusion (BHI) and Meat Extract (ME) was studied using stationary-phase cells grown in non-acidified BHI (pH 7.4) and ME (pH 6.6) and acidified BHI and ME at pH values of 6.4, 5.4 and 4.5 with acetic, ascorbic, citric, lactic, malic and hydrochloric acids. Cells grown in buffered BHI (pH 7.0) were used as non-acid adapted control cells.     

Study on the behavior of the trace metal and macro minerals in Mytilus galloprovincialis as a bioindicator species: the case of Marmara Sea, Turkey

Sea food is a major source of animal protein. Marine foods are very rich sources of mineral components. The total content of minerals in the raw flesh of marine fish and invertebrates is in the range of 0.6–1.5% wet weight. The contents of Na, K, Ca, Mg and P are up to 1 mg/100 g, whereas those of Fe, Zn, I are less than 1 mg/100 g. Mussels (Mytilus galloprovincialis) were investigated for macro and trace element composition throughout the year. Ranges of moisture, ash, protein and fat contents were 79.76–87.46 g/100 g, 1.06–2.06 g/100 g, 7.28–12.65 g/100 g and 0.33–3.49 g/100 g, respectively. While the highest protein and fat values were found in the summer (July–August), the highest moisture and ash contents were found in the winter (December–January). The contents of highest Na, K, Ca were found in the summer. Cadmium, lead and copper were found to be below the legislative limits throughout year. High levels of mercury were found in January and October. It should be discussed whether mussel may provide an alternative source of mineral for healthy nutrition.     

Cadmium bioavailability and accumulation in the presence of humic acid to the zebra mussel, Dreissena polymorpha

Metal speciation in aquatic systems is mainly determined by the type and concentration of ligands present in solution. A very important group of complexing agents is dissolved organic matter (DOM), e.g., humic and fulvic acids. According to the free-ion activity model, only the free metal ion is available to biota. Nevertheless, DOM has been reported to decrease or increase metal uptake, leading to uncertainty concerning the bioavailability of metal-DOM complexes. In this work the effect of Aldrich humic acid on cadmium accumulation by the zebra mussel, Dreissena polymorpha, was studied under laboratory conditions. Mussels, collected in a drinking water reservoir, were exposed to varying environmentally relevant concentrations of cadmium in the presence and absence of humic acid. Cadmium concentrations in the mussel tissues were analyzed, and measurements with a cadmium-ion-selective electrode were made to determine the free cadmium ion activity in the exposure waters. The uptake of humic acid by the zebra mussels was measured by the decrease of the total organic carbon (TOC) concentration in the water over time. The free cadmium ion activity in the water decreased from 51.6% to 19.9% of the total cadmium concentration in the presence of humic acid. This decrease by a factor of 2.6 resulted in a decrease in the cadmium uptake rate in the soft tissue of zebra mussels from 12.9 to 7.9 nmol/g dry wt/day, which corresponds to a decrease by a factor of 1.6. This implies that cadmium uptake rates were higher than predicted by the free-ion activity model and indicates that cadmium-humic acid complexes are partly available to zebra mussels.     

贻贝蒸煮液体外抗氧化及阻断N-亚硝胺合成的研究

为了研究贻贝蒸煮液的抗氧化活性和阻断亚硝胺合成能力,采用DPPH.法测定了试样的抗氧化活性,并模拟胃液在体外进行亚硝胺合成阻断实验,测定了试样对亚硝酸根离子的清除率和N-亚硝胺合成的阻断率。结果表明,在DPPH.清除实验中,贻贝蒸煮液(以可溶性固形物计)的IC50为3.80μg/mL,对照品TBHQ的IC50为7.55μg/mL。另外,贻贝蒸煮液清除亚硝酸根离子与阻断N-亚硝胺合成的最佳剂量水平(以可溶性固形物计)为64μg/mL,此时,清除率和阻断率分别达到84.08%和71.04%,相同浓度下,对照品VC的清除率和阻断率分别为30.90%和29.27%。     

Food riots: Media perspectives on the causes of food protest in Africa

When food prices spiked in 2007–8, urban Africa experienced more instances of food riots than any other part of the world. Problems were then encountered again during the 2010–11 food price spikes. This paper explores the cases of 14 African countries where food riots occurred during these two periods by presenting a qualitative content analysis of news reports on the riots drawn from both global and local African news sources. This analysis highlights the ways in which the media portrayed the links between food price rises and food riots in Africa. Briefly, our results show that the international media generally portrayed poverty and hunger as the factors that linked the incidence of food price rises with the occurrence of riots. By contrast, the African media tended to portray food riots as being caused by a more complex set of factors, including citizen dissatisfaction and people’s ability to mobilize. Exploring both the international and local interpretations of the drivers behind the food riots is important for the understanding of the multi-scalar and multifaceted factors that shape increasing food insecurity in urban Africa.     

Invited review: perspectives on the basis of the rheology and texture properties of cheese

Physical and chemical properties of cheese, such as texture, color, melt, and stretch, are primarily determined by the interaction of casein (CN) molecules. This review will discuss CN chemistry, how it is influenced by the cheese-making process, and how it impinges on the final product, cheese. We attempt to demonstrate that the application of principles governing the molecular interactions of CN can be useful in understanding the many physical and chemical properties of cheese and, in turn, how this can be used by the cheesemaker to produce the desired cheese. The physical properties of cheese (as well as flavor) are influenced by a number of factors including: milk composition; milk quality; temperature; the rate and extent of acidification by the starter bacteria; the pH history of cheese; the concentration of Ca salts (proportions of soluble and insoluble forms); extent and type of proteolysis, and other ripening reactions. Our hypothesis is that these factors also control and modify the nature and strength of CN interactions. The approach behind the recently proposed dual-binding model for the structure and stability of CN micelles is used as a framework to understand the physical and chemical properties of cheese.     

Effect of subcritical water extraction conditions on the activity of alcohol metabolizing enzymes,ACE inhibition,and tyrosinase inhibition in Protaetia brevitarsis larvae

Food Science and Biotechnology - In order to develop processing methods with high physiological activity for Protaetia brevitarsis larvae (PBL), subcritical water (SCW) extraction was applied. The...     

Freshwater mussel shells as environmental chronicles: geochemical and taphonomic signatures of mercury-related extirpations in the North Fork Holston River, Virginia

This study utilized freshwater mussel shells to assess mercury (Hg) contamination in the North Fork Holston River that extirpated (caused local extinctions of) a diverse mussel fauna. Shells (n = 366) were collected from five sites situated upstream (two sites), just below (one site), and downstream (two sites) of the town of Saltville, Virginia, where Hg was used to produce chlorine and caustic soda from 1950 to 1972. Shell samples were used to test the (1) utility of geochemical signatures of shells for assessing the spatial variation in Hg levels in the river relative to the contamination source and (2) value of taphonomy (post-mortem shell alteration) for distinguishing sites that differ in extirpation histories. Geochemical signatures of 40 shells, analyzed using atomic absorption spectroscopy, indicated a strong longitudinal pattern. All shells from the two upstream sites had low Hg concentrations (<5-31 microg/kg), shells directly below Saltville had variable, but dramatically higher concentrations (23-4637 microg/kg), and shells from the two downstream sites displayed intermediate Hg levels (<5-115 microg/kg) that declined with distance from Saltville. Two pre-industrial shells, collected at Saltville in 1917, yielded very low Hg estimates (5-6 microg/kg). Hg signatures were consistent among mussel species, suggesting that Hg concentrations were invariant to species type; most likely, highly variable Hg levels, both across sites and through time, overwhelmed any interspecific differences in Hg acquisition. Also, a notable postmortem incorporation of Hg in mussel shells seemed unlikely, as the Hg content was not correlated with shell taphonomy (r= 0.18; p = 0.28). The taphonomic analysis (n = 366) showed that the degree of shell alteration reliably distinguished sites with different extirpation histories. At Saltville, where live mussels have been absent for at least 30 years, shells were most heavily altered and fragmented. Conversely, fresh-looking shells abounded upstream, where reproducing mussel populations are still present. In summary, relic shells offered valuable spatio-temporal data on Hg concentrations in a polluted ecosystem, and shell taphonomic signatures discriminated sites with different extirpation histories. The shell-based strategies exemplified here do not require sampling live specimens and may augment more standard strategies applied to environmental monitoring. The approach should prove especially useful in areas with unknown extirpation and pollution histories.     

Trust,agreements, and occasional breakdowns: Veterinarians' perspectives on farmer-veterinarian relationships and use of antimicrobials for Swedish dairy cattle

Studies have shown that farmer-veterinarian relationships influence antimicrobial use (AMU) in livestock, though how they do so is unclear. On the one hand, research shows that well-established veterinarian-farmer relationships are positive for implementation of antibiotic stewardship and restrictive AMU. On the other hand, studies also show that farmer demands can increase antimicrobial prescribing and that prescribing antimicrobials can strengthen the veterinarian's relationship with farmer clients. In the present study, we focus on veterinarians' perspectives on the relationships between dairy cattle farmers and veterinarians in Sweden and explore what characterizes these relationships when restrictive AMU is described as unproblematic and when AMU becomes a matter of tension or conflict. The study draws on semistructured interviews with 21 veterinarians working with livestock in Sweden. Interviews were analyzed thematically. The study shows that from the perspectives of veterinarians, well-established veterinarian-farmer relationships generally facilitate restrictive AMU in 3 slightly different but related ways: (1) they create trust in the veterinarian and their prescribing decisions; (2) they create shared understanding concerning when antimicrobials are needed and not needed; and (3) they facilitate constructive discussions between veterinarians and farmers on AMU. To make the farmer feel listened to and to come to an agreement on AMU was described as central for the veterinarians. However, the veterinarians described agreements on restrictive AMU as sometimes requiring strategic work, such as discussions to motivate the farmer and leave the door open for antimicrobials later if needed. Such work takes time and energy and is easier within well-established relationships according to the veterinarians. We also identified examples where veterinarians explained that they occasionally make compromises with farmers concerning antimicrobials—compromises that, according to the veterinarians, facilitate the relationship with the farmer, which in turn facilities restrictive AMU in the longer term. The examples in our interviews where antimicrobials became a matter of tension and even conflict between veterinarians and farmers could, with a few exceptions, be traced to absence of well-established relationships. However, some veterinarians also described AMU as a matter of tension within well-established relationships, especially with older farmers who do not trust new treatment strategies. We also found a small number of examples where disagreements on antimicrobials made a relationship with specific farmers impossible. Thus, even though the interviewed veterinarians generally meant that their restrictive antimicrobial prescribing did not threaten the relationship with the farmer, our study also, to some extent, confirms research showing that restrictive AMU can harm the relationship with some clients who simply choose another, less restrictive, veterinarian. In summary, our study supports that decisions on AMU cannot be reduced to the individual prescriber's behavior, nor to a strict medical judgment. Antimicrobial use for dairy cattle needs to be understood as taking form in relationships in which both veterinarians and farmers are active parts.