Balanced Fatty Acid Intake Benefits and Mercury Exposure Risks: An Integrated Analysis of Chinese Commercial Freshwater Fish and Potential Guidelines for Consumption

Fish-related consumption advisories have emerged based on the benefits of omega-3 fatty acids (omega-3 FA) intake and risks of Hg exposure from marine fish. However, only a few were based from freshwater fish. We integrated omega-3 FA and Hg data available from commonly eaten freshwater fish in China to provide a new perspective on consumption of these fish and also created a guide on the cost of basic omega-3 FA intake of 1750 mg/week. Results show that freshwater fish exhibited low omega-3 FA and Hg levels. The Hg bioaccumulation of functional feeding groups was significantly different (p <.05). Carnivorous species indicated relatively high Hg levels, whereas planktivorous fish species showed high omega-3 FA levels and extremely low costs for basic omega-3 FA intake. Results indicate that an advisory regarding reasonable fish consumption is necessary to maximize omega-3 FA and to minimize Hg exposure risks to fish consumers. This study provides temporary advisories and guide research for the creation of a proper dietary pattern. The advisory could reduce confusion and enforce benefit and risk communication for freshwater fish consumers. However, additional biomonitoring data in fish are needed to create more appropriate and specific freshwater fish consumption guidelines for the public.     

Molecular mechanisms underlying oxygen reception

In this review, modern concepts on molecular mechanisms underlying reception of the oxygen level in natural O₂-sensory structures and cellular in vitro models are considered and discussed.Neirofiziologiya/Neurophysiology, Vol.36, No.4, pp.330–347, July–August, 2004.     

A Dietary Risk Assessment for Indigenous Consumption of Natural Salt Deposits in the Darhad Valley,Northern Mongolia

The nomadic herding population of the Darhad Valley, in northern Mongolia, collects and utilizes a salt precipitate, called hujir, which develops at the saline system, Tohi. This culturally important indigenous dietary supplement is consumed daily as an ingredient in a salty milk-tea and because of its essential micro- and macronutrients it is a beneficial and necessary part of their daily diet. Despite its benefits, there are increasing health concerns among the Darhad people as a result of consuming hujir. Therefore, we conducted a dietary risk assessment. Consumption rates were obtained from interviews with nomadic herders of the valley and a chronic exposure assessment was completed using chemical analyses on hujir samples. A combination of chronic toxicity threshold values, dietary reference intake recommendations, and drinking water guidelines were used to estimate dietary risks related to hujir consumption. Exposures to arsenic, fluoride, and nitrate were as high as 33, 1.2, and 1.3 times the chronic oral reference dose, respectively. Exposures to antimony, arsenic, and lead were 1.7, 19, and 14 times the drinking water guidelines, respectively. Given these results, additional studies are needed to better understand possible health effects associated with hujir consumption in the Darhad population, especially for arsenic.     

Updated Risk/Benefit Analysis of Fish Consumption Effects on Neurodevelopment: Implications for Setting Advisories

Epidemiological studies indicate that fish consumption during pregnancy leads to improved neurodevelopment. This suggests that the beneficial nutrients in fish may offset the adverse effects of mercury in the case of the average fish meal. However, our previous risk/benefit model predicted a net neurodevelopmental risk for the majority of species analyzed. In this article the previous model is calibrated against fish benefit data and then compared to other fish risk/benefit models, including recent models from the World Health Organization and USFDA. Our calibrated model estimated greater benefit for low mercury species but greater risk for high mercury species than the other models. With respect to a commonly eaten high mercury fish, swordfish, the calibrated model yielded risks that are supportive of current fish advisories but, in contrast, the other models predicted net neurodevelopmental benefits. The calibrated model was used in a proposed 3 step framework for setting fish consumption advisories: (1) Set initial consumption level based upon mercury RfD; (2) Adjust consumption upward if risk/benefit model indicates a net benefit; (3) Cap fish consumption based upon saturation of O-3 benefit. The implications of this approach for 7 varieties of fish are used to illustrate the framework.     

Group swimming behaviour and energetics in bluegill Lepomis macrochirus and rainbow trout Oncorhynchus mykiss

Group swimming size influences metabolic energy consumption and swimming behaviour in fishes. Hydrodynamic flows and vortices of other fish are thought to be beneficial in terms of the energetic costs of swimming. Similarly, abiotic obstructions have been shown to have similar benefits with respect to metabolic consumption in swimming fish such as rainbow trout Oncorhynchus mykiss. The current study works to examine metabolic rates and swimming behaviours as a function of group swimming with bluegill sunfish Lepomis macrochirus and O. mykiss. Fishes were subjected to individual and group swimming in a respiratory swim tunnel to determine oxygen consumption as a proxy for the metabolic rate of swimming fish. In addition, fish movements within the swim tunnel test chamber were tracked to examine group swimming behaviour. We hypothesized that fish would benefit metabolically from group swimming. In the case of O. mykiss, we also hypothesized that groups would benefit from the presence of an abiotic structure, as has been previously observed in fish swimming individually. Our results suggest that the influence of group size on swimming metabolism is species specific. While L. macrochirus show decreased metabolic rate when swimming in a group compared to individually, O. mykiss did not show such a metabolic benefit from group swimming.     

Risk of Ill-Informed Decision-Making When Choosing Your Favorite Fish

Risk to children of women who choose a favorite fish without regard to its methylmercury or omega-3 content was estimated under three consumption scenarios: (1) current fish consumption rate by U.S. women if limited to orange roughy (Hoplostethus atlanticus), (2) 12 oz of roughy per week, and (3) roughy consumption to meet docosahexaenoic acid (DHA) requirements. Risks were similarly assessed if king mackerel (Scomberomorus cavalla) were eaten. Based on mercury concentrations in fillets purchased from 2004–2007 (0.73 ± 0.29 mg Hg/kg; n = 45), women would have an 85% probability of exceeding USEPA's reference dose (RfD) if they ate only roughy. Based on literature-derived concentrations, they would have a 91% probability of exceeding the RfD if they ate only mackerel. Increasing consumption of either fish to 12 oz per week would increase their probability of exceeding the RfD to 100%. Attempting to meet DHA requirements through eating these fish also results in a 100% probability of exceeding the RfD; however, owing to its very low DHA content, roughy consumption would result in exceedance by 100-fold. These results highlight recommendations of others that benefits and risks of fish consumption should be presented together to enable consumers to make informed decisions.     

Behavior of food objects testing by taste in the carp <Emphasis Type="Italic">Cyprinus carpio</Emphasis> in the norm and at chronic anosmia

Comparative study of behavior of testing artificial food objects (agar-agar pellets containing L-proline 0.1 M, L-alanine 0.1 M, L-glutamine 0.1 M, or L-glutamic acid 0.01 M and control pellets) by intact and olfactorily deprived (16 months) two-year-olds of the carp Cyprinus carpio (TL 8.5 cm) was performed. It was found that chronic anosmia causes in fish an increase in the latent time of response to food objects (period from pellet falling in water up to the moment of its being grasped by fish); however, the main characteristics of behavior related to sensory testing (intraoral gustatory reception) of suitability of food objects for consumption do not change in fish. Intact and deprived carps retain the pellet in the oral cavity at the first grasp for a maximum time and reduce this time with each subsequent retention, whereas the duration of intervals between the grasps do not obey this regularity. In experiments that terminate with pellet consumption, fish perform considerably less repeated acts of testing and retain the pellet at each grasping several times longer than in experiments terminating with the rejection by fish from its consumption. It is suggested that the sensory properties of the food object are evaluated by fish at the moment of its first grasping and that the results of such assessment are the basis for the subsequent behavior whose development can proceed according to two different stereotypes.     

Assessment of protein rotational diffusion by 13C off-resonance rotating frame spin–lattice relaxation: Effect of backbone and side-chain internal motion

The ¹³C off-resonance rotating frame spin–lattice relaxation technique is applicable to the study of protein rotational diffusion behavior in a variety of experimental situations. The original formalism of James and co-workers (1978) (J. Am. Chem. Soc. Vol. 100, pp. 3590–3594) incorporated random isotropic reorientational motion of a rigid spherical rotor with no provision for backbone or side-chain carbonyl group internal motion. Here we demonstrate that the failure to include such internal motion may lead to erroneous rotational correlation time determinations for overall reorientational motion. The effect becomes severe for protein molecular masses in excess of 100 kD. Inclusion of both backbone and side-chain carbonyl carbon internal motion, using reasonable parameters derived from the literature [R. Levy and M. Karplus (1979), Chemical Physics Letters, Vol. 65, pp. 4–11; G. Careri, P. Fasella, and E. Gratton (1975), Critical Reviews in Biochemistry, Vol. 3, pp. 141–164; G. Lipari, A. Szabo, and R. Levy (1982), Nature, Vol. 300, pp. 197–198], plus corrections for anisotropic tumbling [C. F. Morgan, T. Schleich, G. H. Caines, and D. Michael (1990), Biopolymers, Vol. 29, pp. 469–480] and microscopic viscosity [S. H. Koenig (1980), ACS Symposium. Series, Vol. 127, pp. 157–176], leads to reliable values for the correlation time describing overall protein reorientation up to molecular masses of approximately 1000 kD. © 1993 John Wiley & Sons, Inc.     

Skull structure of the flying fish Cheilopogon pinnatibarbatus (Beloniformes, Exocoetidae)

The skull of the flying fish Cheilopogon pinnatibarbatus is first described in comparison with literature data on other four-winged flying fishes (subfamily Cypselurinae). The skull of Ch. pinnatibarbatus is characterized by the following features: (1) a multitude (about 40) of minute pores in the canal of the lateral line of the nasale; (2) a big opening in the roof of the myodome; (3) the lateral line canal of dentale by far does not reach the symphysis; (4) the tip of praeoperculum does not reach the upper edge of the hyomandibulare; (5) the posterior part of the angulare is weakly covered by the articulare and almost reaches from the outside the joint for articulation with the quadratum. Ppublished in Voprosy Ikhtiologii, 2007, Vol. 47, No. 3, pp. 284–291. This article was submitted by the authors in English.     

Model requirements for Biobank Software Systems

Biobanks are essential tools in diagnostics and therapeutics research and development related to personalized medicine. Several international recommendations, standards and guidelines exist that discuss the legal, ethical, technological, and management requirements of biobanks. Today's biobanks are much more than just collections of biospecimens. They also store a huge amount of data related to biological samples which can be either clinical data or data coming from biochemical experiments. A well-designed biobank software system also provides the possibility of finding associations between stored elements. Modern research biobanks are able to manage multicenter sample collections while fulfilling all requirements of data protection and security. While developing several biobanks and analyzing the data stored in them, our research group recognized the need for a well-organized, easy-to-check requirements guideline that can be used to develop biobank software systems. International best practices along with relevant ICT standards were integrated into a comprehensive guideline: The Model Requirements for the Management of Biological Repositories (BioReq), which covers the full range of activities related to biobank development. The guideline is freely available on the Internet for the research community. AVAILABILITY: The database is available for free at http://bioreq.astridbio.com/bioreq_v2.0.pdf.     

Individual-site binding data and the energetics of protein–DNA interactions

Individual-site isotherms for the binding of bacteriophage λ repressor to the left and right λ operators have been determined [D. F. Senear, M. Brenowitz, M. A. Shea, and G. K. Ackers (1986) Biochemistry, Vol. 25, pp. 7344–7354.] using the DNAse protection technique [ footprinting; D. J. Galas and A. Schmitz (1978) Nucleic Acids Research, Vol. 5, pp. 3157–3170]. These extensive data have been interpreted with a quantitative model that emphasized cooperative interactions between adjacently bound ligands [occupied ? occupied interactions; G. K. Ackers, A. D. Johnson, and M. A. Shea (1982) Proceedings of the National Academy of Science, USA, Vol. 79, pp. 1129–1133]. Overlooked in this model are the effects of cooperative interactions between a site containing a bound ligand and its neighboring unoccupied site (occupied ? unoccupied interactions). This paper reinterprets the existing data with a model that considers occupied ? unoccupied as well as occupied ? occupied interactions. The results yield parameters that differ substantially from those already reported. A discussion on the advisability of ignoring occupied ? unoccupied interactions is included. © 1993 John Wiley & Sons, Inc.     

Regulation of the Fish Alimentary Behavior: Role of Humoral Component

Based on our own personal experimental data and literature data, role of some metabolites and hormones in regulation of the fish alimentary behavior is considered. The main statements of the synthetic theory of regulation of the alimentary behavior are presented.__________Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 3, 2005, pp. 224–235.Original Russian Text Copyright © 2005 by Kuz’mina.     

Cover

Lithothamnion sp. protuberance of rhodolith sample LAF1437A. An empty conceptacle located at the left, aragonite infill appears brighter than other structures. 3‐D image produced with ZEISS Xradia 520 Versa' X‐ray Microscope and ORS Visual SI Advanced software. [Vol. 52, No. 2, pp. 161–173]     

Frequency characteristics of skate electroreceptive central neurons responding to electrical and magnetic stimulation

Responses of single neurons in the lateral lobes of the medulla to stimulation of the electroreceptive system by homogeneous sinusoidal electrical and magnetic fields were investigated in acute experiments on the skateRaja radiata. Thresholds of neuronal responses to electrical stimulation varied from 0.03 to 10 µV/cm. The optimal frequency ranges for electrical and magnetic reception were in the regions of 0.05–5 and 2–3 Hz respectively. The possible mechanisms and functional significance of frequency characteristics of central neurons are discussed.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. All-Union Cardiologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 16, No. 4, pp. 464–470, July–August, 1984.     

Examining the Impact of a Public Health Message on Fish Consumption in Bermuda

Background

In 2003 mean cord blood mercury concentrations in pregnant Bermudian women exceeded levels associated with adverse health outcomes in children. The principal mercury source was local fish species. Public health messages were developed suggesting pregnant women reduce consumption of fish species with higher mercury concentrations (e.g. swordfish), substituting species containing lower mercury concentrations, and elevated omega-3 fatty acids (e.g. anchovies). Recent evidence indicates mercury concentrations in Bermuda’s pregnant women have fallen five- fold.

Objectives

Assess whether changes in women’s fish eating patterns during pregnancy are consistent with the public health messaging. Determine who is making changes to their diet during pregnancy and why.

Methods

Mixed methods study with a cross-sectional survey of 121 pregnant women, including 13 opened-ended interviews. Health system, social vulnerability, public health messaging, and socio-demographic variables were characterized and related to changes in fish consumption during pregnancy. Qualitative data were coded according to nutritional advice messages, comprehension of communication strategies, and sources of information.

Results

95% of women surveyed encountered recommendations about fish consumption during pregnancy. 75% reported modifying fish eating behaviors because of recommendations. Principal sources of information about fish consumption in pregnancy were health care providers and the Internet. 71% of women reported reducing consumption of large fish species with greater mercury levels, but 60% reported reduced consumption of smaller, low mercury fish. No participant mentioned hearing about the benefits of fish consumption. More frequent exposure to public health messages during pregnancy was associated with lower reported consumption. Bermudian born women were less likely to reduce consumption of large fish species during pregnancy.

Conclusions

In Bermuda, public health messages advocating reduced consumption of larger, higher mercury-containing fish species appear effective, but masked the nutritional value message of small fish species, with low mercury concentration. Adjustment is needed to better balance the risk communication.     

Mechanism of perception of changes in the magnetic field by ampullae of lorenzini of elasmobranchs

The mechanisms of reception of changes in the magnetic field by electroreceptor formations were investigated in experiments on Black Sea rays in which spike activity was recorded from single nerve fibers connected with the ampullae of Lorenzini. The responses of the ampullae of Lorenzini to magnetic stimulation were shown to be due to induced electric currents creating potential gradients in the body tissues of the fish and the sea water. On the basis of differences in responses of different ampullae to magnetic stimulation, it is possible to distinguish between magnetic stimuli and other stimuli acting on the electroreceptor system. Potentiation of the receptor response to magnetic stimulation was found as the fish came closer to the "shore." The mechanisms and biological importance of reception of changes in the magnetic field by the ampullae of Lorenzini are discussed.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 10, No. 1, 75–83, January–February, 1978.     

Persistence analysis of the static and dynamical helix deformations of DNA oligonucleotides: Application to the crystal structure and molecular dynamics simulation of d(CGCGAATTCGCG)2

A theory and graphical presentation for the analysis of helix structure and deformations in oligonucleotides is presented. The parameters “persistence” and “flexibility” as defined in the configurational statistics of polymers of infinite length are reformulated at the oligonucleotide level in an extension of J. A. Schellman's method [(1974) Biopolymers, Vol. 17, pp. 217–226], and used as a basis for a systematic “Persistence Analysis” of the helix deformation properties for all possible subsequences in the structure. The basis for the analysis is a set of link vectors referenced to individual base pairs, and is limited to sequences exhibiting only perturbed rod-like behavior, i.e., below the threshold for supercoiling. The present application of the method is concerned with a physical model for the angular component of bending, so the link vectors are defined as the unit components of a global helix axis obtained by the procedure “Curves” of R. Lavery and H. Sklenar [(1988) J. Biomol. Struct. Dynam., Vol. 6, pp. 63–91; (1989) J. Biomol. Struct. Dynam., Vol. 6, pp. 655–667]. A discussion, of the relationship between global bending and relative orientation of base pairs is provided. Our approach is illustrated by analysis of some model oligonucleotide structures with intrinsic kinks, the crystal structure of the dodecamer d (CGCGAATTCGCG)₂, and the results of two molecular dynamics simulations on this dodecamer using two variations of the GROMOS force field. The results indicate that essentially all aspects of curvature in short oligonucleotides can be determined, such as the position and orientation of each bend, the sharpness or smoothness, and the location and linearity of subsequences. In the case of molecular dynamics simulations, where a Boltzmann ensemble of structures is analyzed, the spatial extent of the deformations (flexibility) is also considered. © 1993 John Wiley & Sons, Inc.     

Taste preferences and feeding behavior of the stone loach <Emphasis Type="Italic">Barbatula barbatula</Emphasis> (Balitoridae,Cypriniformes) after partial deprivation of circum-mouth external gustatory and tactile receptors

Comparative study of the feeding behavior and gustatory preferences mediated by extraoral and intraoral gustatory reception in the stone loach Barbatula barbatula in the norm and 1–6 months after extirpation of all three pairs of barbels was performed. It was found that partial loss of external gustatory receptors and the sensory deficit caused by it do not lead to any noticeable disturbances of the ability of fish to evaluate taste properties of food objects (artificial agar-agar pellets containing L-isomers of alanine, lysine, cysteine or an water extract of chironomid larvae) and make an adequate decision of their grasping or ignoring and swallowing or refusing. The extirpation of the barbels does not influence feeding behavior related to determination by fish of the taste properties of pellets and completely retains in its ritual an obligatory preliminary examination of the food object using external gustatory reception. It is suggested that external taste buds having different localization are equally capable of providing for fish a preliminary evaluation of the taste properties of the object. After extirpation of the barbels, the efficiency of grasping pellets decreases in fish, which indicates an important role of tactile reception in the determination of the site of location of the food object and in providing of the accuracy of the hunter’s dart in fish with a weak vision development.     

Human Exposure to Dioxin-Like Compounds in Fish and Shellfish Consumed in South Korea

Dietary intake is the most important source of exposure to dioxins for the general population. This pathway contributes more than 90% of the daily intake for the general population of Korea. The objective of this study was to assess current exposure to dioxin-like compounds in fish and shellfish consumed by the general population in Korea. Residues of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and dioxin-like, non-, and mono-substituted polychlorinated biphenyls (co-planar PCBs) were quantified in 32 fish and shellfish collected from domestic fisheries markets. The contributions of individual DL-PCB congeners to the total 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEQ) were greater than 50%. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents based on the TCDD equivalency factors (TEFs) developed by the World Health Organization (TEQ_WHO) were compared to guidelines suggested for the protection of human health by the World Health Organization (WHO). The greatest TEQ concentration was observed in herring, followed by that in dried anchovy and Sailfin sandfish. The exposure to dioxin-like compounds from current fish consumption patterns was estimated to be 72 pg TEQ_WHO/day, which is equal to 1.2 pg TEQ_WHO/kg, bw/d, a value that is less than the current tolerable daily intake (TDI) guideline in Korea, which is 4 pg TEQ_WHO/kg, bw/d. The relatively great exposure was determined to be due to greater fish consumption rate in Korea, rather than greater concentrations of residues in food.