Heavy metal concentrations in,and human health risk assessment of,three commercially valuable fish species in the lower Niger River,Nigeria

The concentrations of Fe, Mn, Ni, Pb and V in water, sediment and the gill, liver and muscle tissues of Synodontis resupinatus, Heterotis niloticus and Clarias gariepinus, all commercially important fish species of the lower Niger River, were investigated in 2015. Water, sediment and fish samples were collected for six months and heavy metals were determined using an Atomic Absorption Spectrometer. Fe ranked highest in water and sediment, with concentrations of 2.74 mg l^?1 and 61.60 mg kg^?1, respectively. Metals followed the magnitude of Fe > Mn > Ni > V > Pb in the water and Fe > Mn > V > Ni > Pb in the sediments. Metal concentrations were higher in the tissues of S. resupinatus compared with H. niloticus and C. gariepinus. Fe was also highest in the gills, liver and muscle of the three fish species. Its highest concentration of 132.97 mg kg^?1 dry weight was recorded in the gills of S. resupinatus. Bioconcentration factors of metals ranged from 8.79 for Mn in H. niloticus muscle to 67.99 for Ni in S. resupinatus gills. The fish species studied pose no health risk for all metals studied, because the target hazard quotient was less than 1 and the estimated daily intakes of the metals were below the reference doses.     

Diversity of oligopeptide transport specificity in Lactococcus lactis species. A tool to unravel the role of OppA in uptake specificity

The specific oligopeptide transport system Opp is essential for growth of Lactococcus lactis in milk. We examined the biodiversity of oligopeptide transport specificity in the L. lactis species. Six strains were tested for (i) consumption of peptides during growth in a chemically defined medium and (ii) their ability to transport these peptides. Each strain demonstrated some specific preferences for peptide utilization, which matched the specificity of peptide transport. Sequencing of the binding protein OppA in some strains revealed minor differences at the amino acid level. The differences in specificity were used as a tool to unravel the role of the binding protein in transport specificity. The genes encoding OppA in four strains were cloned and expressed in L. lactis MG1363 deleted for its oppA gene. The substrate specificity of these engineered strains was found to be similar to that of the L. lactis MG1363 parental strain, whichever oppA gene was expressed. In situ binding experiments demonstrated the ability of OppA to interact with non-transported peptides. Taken together, these results provide evidence for a new concept. Despite that fact that OppA is essential for peptide transport, it is not the (main) determinant of peptide transport specificity in L. lactis.     

Mouse functional genomics requires standardization of mouse handling and housing conditions

The study of mouse models is crucial for the functional annotation of the human genome. The recent improvements in mouse genetics now moved the bottleneck in mouse functional genomics from the generation of mutant mice lines to the phenotypic analysis of these mice lines. Simple, validated, and reproducible phenotyping tests are a prerequisite to improving this phenotyping bottleneck. We analyzed here the impact of simple variations in animal handling and housing procedures, such as cage density, diet, gender, length of fasting, as well as site (retro-orbital vs. tail), timing, and anesthesia used during venipuncture, on biochemical, hematological, and metabolic/endocrine parameters in adult C57BL/6J mice. Our results, which show that minor changes in procedures can profoundly affect biological variables, underscore the importance of establishing uniform and validated animal procedures to improve reproducibility of mouse phenotypic data.     

SOSORT 2012 consensus paper: reducing x-ray exposure in pediatric patients with scoliosis

This 2012 Consensus paper reviews the literature on side effects of x-ray exposure in the pediatric population as it relates to scoliosis evaluation and treatment. Alternative methods of spinal assessment and imaging are reviewed, and strategies for reducing the number of radiographs are developed. Using the Delphi technique, SOSORT members developed consensus statements that describe how often radiographs should be taken in each of the pediatric and adolescent sub-populations.     

Risk Assessment of Genetically Modified Lactic Acid Bacteria Using the Concept of Substantial Equivalence

The use of food-grade microorganisms such as lactic acid bacteria (LAB) is one of the most promising methods for delivering health promoting compounds. Since it is not always possible to obtain strains that have the ability to produce specific compounds naturally or that produce them in sufficient quantities to obtain physiological responses, genetic modifications can be performed to improve their output. The objective of this study was to evaluate if previously studied genetically modified LAB (GM-LAB), with proven in vivo beneficial effects, are just as safe as the progenitor strain from which they were derived. Mice received an elevated concentration of different GM-LAB or the native parental strain from which they were derived during a prolonged period of time, and different health parameters were evaluated. Similar growth rates, hematological values, and other physiological parameters were obtained in the animals that received the GM-LAB compared to those that were fed with the native strain. These results demonstrate that the GM-LAB used in this study are just as safe as the native strains from which they were derived and thus merit further studies to include them into the food chain.     

A nuclear gene for higher level phylogenetics: phosphoenolpyruvate carboxykinase tracks mesozoic-age divergences within Lepidoptera (Insecta)

The sequence of phosphoenolpyruvate carboxykinase (PEPCK) has been previously identified as a promising candidate for reconstructing Mesozoic-age divergences (Friedlander, Regier, and Mitter 1992, 1994). To test this hypothesis more rigorously, 597 nucleotides of aligned PEPCK coding sequence (approximately 30% of the coding region) were generated from 18 species representing Mesozoic-age lineages of moths (Insecta: Lepidoptera) and outgroup taxa. Relationships among basal Lepidoptera are well established by morphological analysis, providing a strong test for the utility of a gene which has not previously been used in systematics. Parsimony and other phylogenetic analyses were conducted on nucleotides by codon positions (nt1, nt2, nt3) separately and in combination, and on amino acids, for comparison to the test phylogeny. The highest concordance was achieved with nt1 + nt2, for which one of two most-parsimonious trees was identical to the test phylogeny, and with all nucleotides when nt3 was down-weighted sevenfold or higher, for which a single most-parsimonious tree identical to the test phylogeny resulted. Substitutions in nt3 approached saturation in many, but not all, pairwise comparisons and their exclusion or severe downweighting greatly increased the degree of concordance with the test phylogeny. Neighbor-joining analysis confirms this finding. The utility of PEPCK for phylogenetics is demonstrated over a time span for which few other suitable genes are currently available.      

Plasmid profiles and curing of plasmids in Lactobacillus plantarum strains isolated from green olive fermentations.

Plasmid profiles of 35 Lactobacillus plantarum strains isolated from different green olive fermentors were obtained. A large number of plasmids in the CCC form (from 5 to 16) were present in all the tested strains as confirmed by a second dimension electrophoresis of DNA. These plasmids, all of which remain cryptic, ranged from 2.0 to 68 kb in size. Novobiocin, sodium dodecyl sulphate and ethidium bromide were used as plasmid-curing agents but only novobiocin induced loss of extrachromosomal DNA at a high frequency in these strains.