How the Neurotoxin ß-N-Methylamino-l-Alanine Accumulates in Bivalves: Distribution of the Different Accumulation Fractions among Organs.

The environmental neurotoxin ß-methylamino-l-alanine (BMAA) may represent a risk for human health. BMAA accumulates in freshwater and marine organisms consumed by humans. However, few data are available about the kinetics of BMAA accumulation and detoxification in exposed organisms, as well as the organ distribution and the fractions in which BMAA is present in tissues (free, soluble bound or precipitated bound cellular fractions). Here, we exposed the bivalve mussel Dreissena polymorpha to 7.5 µg of dissolved BMAA/mussel/3 days for 21 days, followed by 21 days of depuration in clear water. At 1, 3, 8, 14 and 21 days of exposure and depuration, the hemolymph and organs (digestive gland, the gills, the mantle, the gonad and muscles/foot) were sampled. Total BMAA as well as free BMAA, soluble bound and precipitated bound BMAA were quantified by tandem mass spectrometry. Free and soluble bound BMAA spread throughout all tissues from the first day of exposure to the last day of depuration, without a specific target organ. However, precipitated bound BMAA was detected only in muscles and foot from the last day of exposure to day 8 of depuration, at a lower concentration compared to free and soluble bound BMAA. In soft tissues (digestive gland, gonad, gills, mantle and muscles/foot), BMAA mostly accumulated as a free molecule and in the soluble bound fraction, with variations occurring between the two fractions among tissues and over time. The results suggest that the assessment of bivalve contamination by BMAA may require the quantification of total BMAA in whole individuals when possible.

Usability of the bivalves Dreissena polymorpha and Anodonta anatina for a biosurvey of the neurotoxin BMAA in freshwater ecosystems.

The environmental neurotoxin ß-methylamino-L-alanine (BMAA) may represent a risk for human health in case of chronic exposure or after short-term exposure during embryo development. BMAA accumulates in freshwater and marine organisms consumed by humans. It is produced by marine and freshwater phytoplankton species, but the range of producers remains unknown. Therefore, analysing the phytoplankton composition is not sufficient to inform about the risk of freshwater contamination by BMAA. Filter-feeders mussels have accumulation capacities and therefore appear to be relevant to monitor various pollutants in aquatic ecosystems. We investigated the suitability of the freshwater mussels Dreissena polymorpha and Anodonta anatina for monitoring BMAA in water. Both species were exposed to 1, 10, and 50 µg of dissolved BMAA/L daily for 21 days, followed by 42 days of depuration in clean water. On days 0, 1, 7, 14, and 21 of exposure and 1, 7, 14, 21 and 42 of depuration, whole D. polymorpha and digestive glands of A. anatina were sampled, and the total BMAA concentration was measured. D. polymorpha accumulated BMAA earlier (from day 1 at all concentrations) and at higher tissue concentrations than A. anatina, which accumulated BMAA from day 14 when exposed to 10 µg BMAA/L and from day 7 when exposed to 50 µg BMAA/L. As BMAA accumulation by D. polymorpha was time and concentration-dependent, with a significant elimination during the depuration period, this species may be able to reflect the levels and dynamics of water contamination by dissolved BMAA. The species A. anatina could be used for monitoring water concentrations above 10 µg BMAA/L.

Living apart together-bacterial volatiles influence methanotrophic growth and activity.

Volatile organic compounds play an important role in microbial interactions. However, little is known about how volatile-mediated interactions modulate biogeochemical processes. In this study, we show the effect of volatile-mediated interaction on growth and functioning of aerobic methane-oxidizing bacteria, grown in co-culture with five different heterotrophs. Both growth and methane oxidation of Methylobacter luteus were stimulated by interaction with specific heterotrophs. In Methylocystis parvus, we observed significant growth promotion, while methane oxidation was inhibited. Volatolomics of the interaction of each of the methanotrophs with Pseudomonas mandelii, revealed presence of a complex blend of volatiles, including dimethylsulfide, dimethyldisulfide, and bicyclic sesquiterpenes. Although the ecological role of the detected compounds remains to be elucidated, our results provide unprecedented insights into interspecific relations and associated volatiles for stimulating methanotroph functioning, which is of substantial environmental and biotechnological significance.

Organohalogen exposure in a Eurasian Eagle owl (Bubo bubo) population from Southeastern Spain: temporal-spatial trends and risk assessment.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine insecticides (OCs) were analysed in 58 Eurasian Eagle owl (Bubo bubo) unhatched eggs collected between 2004 and 2009 in Southeastern Spain. Levels of p,p'-DDE were found to be higher than in eggs laid by other European owls in the same decade, probably due to the greater agricultural activity in our study area. Compared to other European raptors, exposure to PCBs can be considered intermediate, but low to PBDEs. Land use differences and prey availability were the rationale to divide the study area in two subareas in further assessments. Temporal trends of HCB, p,p'-DDE, ß-HCH, PCBs and PBDEs were significantly different in each subarea, generally increasing over time in the Southern but decreasing or remaining stable in the Northern. On the contrary, levels of cyclodienes tended to decrease in both subareas. Dietary shifts with a greater amount of birds are suggested as a cause for increasing organochlorine loads in raptors. This may explain the increasing trend in the Southern territories. However, due to the proximity of most of these nests to Cartagena, an important industrial city, increasing environmental pollution cannot be ruled out. Although average levels of the compounds analysed are below threshold levels, 17% of the samples exceeded 400 pg g(-1)ww (wet weight), the LOAEC for Total TEQs. Moreover, a negative correlation between TEQ concentrations and the metabolizable fraction of PCBs (F(prob)=0.0018) was found when TEQs values were above 10 pg g(-1)ww. This could be indicative of hepatic enzymes induction in the birds exposed at higher concentrations, which are mainly breeding in the Southern subarea. These females could be suffering from Ah-receptor-related toxic effects, some of which have been related to altered bird reproduction. Finally, a significant negative correlation between p,p'-DDE levels and eggshell thickness (r=-0.469, p<0.001) was observed, with about 17% of eggshell thinning for eggs with p,p'-DDE levels above 100 µg g(-1)lw. The persistence of this degree of thinning over a period of time has been related to population declines in other raptor species.

Endoscopically assisted reduction of anterior table frontal sinus fractures.

AIMS: To present a retrospective series of six patients with endoscopically assisted reduction of anterior table frontal sinus fractures. MATERIALS AND METHODS: The patients with isolated anterior table fractures were treated between April 2005 and June 2006 in the Leiden University Medical Centre. In two of the six patients the procedure was performed under local anaesthesia. The endoscope was introduced via existing lacerations, an incision in a natural skin crease or just above the hairline. The fracture was reduced and if necessary fixed. RESULTS: In all patients restoration of the cosmetic deformity was achieved clinically. CONCLUSION: The use of endoscopes makes minimally invasive reduction of outer table fractures of the frontal sinus possible, even under local anaesthesia.

Theory and application of landfarming to remediate polycyclic aromatic hydrocarbons and mineral oil-contaminated sediments; beneficial reuse.

When applying landfarming for the remediation of contaminated soil and sediment, a fraction of the soil-bound contaminant is rapidly degraded; however, a residual concentration may remain, which slowly degrades. Degradation of polycyclic aromatic hydrocarbons (PAHs) and mineral oil can be described using a multi-compartment model and first-order kinetics, in which three degradable fractions are distinguished; (1) rapid, (2) slowly, and (3) very slowly degradable. Using this model populated with data from long-term experiments (initiated in 1990), it is shown that time frames from years to decades can be necessary to clean the soil or sediment to obtain a target below regulatory guidelines. In passive landfarms without active management, three principal potentially limiting factors can be identified: (1) availability of appropriate microorganisms, (2) supply of oxygen for the biodegradation process, and (3) bioavailability of the pollutants to the microorganisms. Bioavailable PAHs and mineral oil are readily biodegradable contaminants under aerobic conditions, and presence and activity of microorganisms are not problems. The other two factors can be limiting and are theoretically described. Using these descriptions, which are in agreement with field experiments of 10 to 15 yr, it is shown if and when optimization of the biodegradation process is an option. Because a long time period is necessary to degrade the slowly and very slowly degradable fractions, passive landfarming should be combined with beneficial use of the land area. Examples include the development of natural environments, use in constructions, growing of biomass for energy production, including biofuels, and use as cover for landfills.

Correlation between peripheral CA-125 levels and ovarian activity.

Serum CA-125 concentrations were measured at three different times in normal cycles, pill-suppressed cycles, and cycles stimulated for intrauterine insemination (IUI) or oocyte retrieval, i.e., (1) during the first half of the cycle, (2) at midcycle or at the moment of oocyte retrieval, and (3) the second half of the cycle. Significant variations of serum CA-125 concentrations were not seen during the cycle in normally cycling women or in women taking oral contraceptives: mean +/- SD 28.9 +/- 13.3 U/mL and 26.9 +/- 11.3 U/mL, respectively. In patients stimulated for in vitro fertilization, luteal phase CA-125 levels (60.6 +/- 38 U/mL) were significantly higher than during stimulation (21.5 +/- 5.9 U/mL) or at oocyte retrieval (19.6 +/- 6.4 U/mL). In stimulated cycles for IUI, without laparoscopy or follicular puncture, a comparable rise of CA-125 was observed in the luteal phase (49.6 +/- 37.8 U/mL). However, in patients undergoing laparoscopic sterilization, serum CA-125 concentrations before and after laparoscopy were not significantly different (22.8 +/- 6.3 U/mL and 25 +/- 4.2 U/mL, respectively).

Dogfish alpha-crystallin sequences. Comparison with small heat shock proteins and Schistosoma egg antigen.

The amino acid sequences of the alpha-crystallin A and B chains of the dogfish, Squalus acanthias, have been determined. Comparison with alpha-crystallins from other species reveals that charged amino acid replacements have been strongly avoided in the evolution of this lens protein. The homology of alpha-crystallins with the small heat shock proteins is pronounced throughout the major part of the proteins, starting from the position of the first intron in the alpha-crystallin genes, but is also detectable in the amino-terminal sequences of human, Xenopus, and Drosophila small heat shock proteins. In addition, a remarkable short sequence similarity is present only in the amino termini of dogfish alpha B and Drosophila HSP22. The Schistosoma egg antigen p40 turns out to have a tandemly repeated region of homology with the common sequence domain of alpha-crystallins and small heat shock proteins. Comparison of hydropathy profiles indicates the conservation of conformation of the common domains in these three families of proteins. Construction of phylogenetic trees suggests that the alpha A and alpha B genes apparently originated from a single ancestral small heat shock protein gene and indicates that introns have been lost during the evolution of the heat shock protein genes.

[The diagnostic value of the 'skyline' view for the radiographic study of the navicular bone in horses]. / De diagnostische betekenis van de 'skyline'-opname ten behoeve van het röntgenologisch onderzoek van het straalbeen van het paard.

The radiographic diagnostic value of Rose's palmaroproximal-dorsodistal ('skyline') projection and Oxspring's dorsopalmar projection of the equine navicular bone were compared, by examining radiographs of 102 navicular bones originating from 66 randomly selected horses with clinical evidence of lameness located in the navicular area. In 27 navicular bones essential information was obtained from the skyline view, 15 independently of Oxspring's projection and 12 in addition to this view. For 11 navicular studies the D.P. projection was the most important diagnostic view. In the other 64 navicular bones information obtained from both views was of equal diagnostic value. Based on these results it is suggested that the skyline projection be utilised as an additional view, especially if there is a significant discrepancy between the clinical and radiographic findings based on lateromedial and Oxspring projections, and if ill-defined lesions of unknown significance are visible on the Oxspring projection.

alpha-Crystallin A sequences of Alligator mississippiensis and the lizard Tupinambis teguixin: molecular evolution and reptilian phylogeny.

The amino acid sequences of the eye lens protein alpha-crystallin A from many mammalian and avian species, two frog species, and a dogfish have provided detailed information about the molecular evolution of this protein and allowed some useful inferences about phylogenetic relationships among these species. We now have isolated and sequenced the alpha-crystallins of the American alligator and the common tegu lizard. The reptilian alpha A chains appear to have evolved as slowly as those of other vertebrates, i.e., at two to three amino acid replacements per 100 residues in 100 Myr. The lack of charged replacements and the general types and distribution of replacements also are similar to those in other vertebrate alpha A chains. Maximum-parsimony analyses of the total data set of 67 vertebrate alpha A sequences support the monophyletic origin of alligator, tegu, and birds and favor the grouping of crocodilians and birds as surviving sister groups in the subclass Archosauria.

epsilon-Crystallin, a novel avian and reptilian eye lens protein.

Gel filtration of Peking duck eye lens proteins reveals a component eluting just behind delta-crystallin and comprising approximately 10% of the total soluble protein. The native Mr of this additional component is estimated to be 120000; it appears to be composed of three identical chains of Mr 38000 and pI 7.5. Circular dichroic spectroscopy showed a relatively high alpha-helical content. No immunological cross-reactivity is found with alpha-, beta-, gamma- or delta-crystallins, and partial amino acid sequence determinations likewise failed to reveal any similarity with other known crystallins. We conclude that this protein represents another and novel family of eye lens proteins, for which we propose the designation epsilon-crystallin. epsilon-Crystallin is translated from a 1450-base mRNA, which has been partially purified. epsilon-Crystallin is found scattered among avian and reptilian taxa, but not in other vertebrates. Its rate of evolutionary change seems to be as slow as that of alpha- and beta-crystallins.

Primary structures of the alpha-crystallin A chains of twenty-eight mammalian species, chicken and frog.

The amino acid sequences of the alpha-crystallin A chains of 28 mammalian species, representing 14 different orders, have been analyzed, mainly on the basis of amino acid compositions of the composing peptides. The alpha A sequences of chicken and a frog have been completely determined by Edman degradation. A method is described to transport eye lenses, to be used for protein sequence studies, at ambient temperature in a solution of guanidine . HCl. The number of cysteine residues in different alpha A chains could be determined by alkaline urea gel electrophoresis after aminoethylation . In some cases the alpha A chains have been isolated from total lens extracts in a single ion-exchange chromatographic step. The average rate of substitutions in the evolution of the alpha A chains is moderately slow, approximately 3 amino acid substitutions per 100 residues in 100 million years, but varies considerably in different lineages. Substitutions involving changes in charge are strongly underrepresented; the alpha A chains tend to keep their net charge constant throughout evolution. Analysis of the types of substitutions suggests a directional trend leading to an increase in functional density of alpha A in the course of evolution.