In Situ Exposure to Low Herbicide Concentrations Affects Microbial Population Composition and Catabolic Gene Frequency in an Aerobic Shallow Aquifer

The aim of this study was to evaluate how the in situ exposure of a Danish subsurface aquifer to phenoxy acid herbicides at low concentrations (<40 μg l⁻¹) changes the microbial community composition. Sediment and groundwater samples were collected inside and outside the herbicide-exposed area and were analyzed for the presence of general microbial populations, Pseudomonas bacteria, and specific phenoxy acid degraders. Both culture-dependent and culture-independent methods were applied. The abundance of microbial phenoxy acid degraders (10⁰ to 10⁴ g⁻¹ sediment) was determined by most probable number assays, and their presence was only detected in herbicide-exposed sediments. Similarly, PCR analysis showed that the 2,4-dichlorophenoxyacetic acid degradation pathway genes tfdA and tfdB (10² to 10³ gene copies g⁻¹ sediment) were only detected in sediments from contaminated areas of the aquifer. PCR-restriction fragment length polymorphism measurements demonstrated the presence of different populations of tfd genes, suggesting that the in situ herbicide degradation was caused by the activity of a heterogeneous population of phenoxy acid degraders. The number of Pseudomonas bacteria measured by either PCR or plating on selective agar media was higher in sediments subjected to high levels of phenoxy acid. Furthermore, high numbers of CFU compared to direct counting of 4′,6-diamidino-2-phenylindole-stained cells in the microscope suggested an increased culturability of the indigenous microbial communities from acclimated sediments. The findings of this study demonstrate that continuous exposure to low herbicide concentrations can markedly change the bacterial community composition of a subsurface aquifer.     

Do female pied flycatchers seek extrapair copulations with familiar males? A test of the incomplete knowledge hypothesis

In birds with biparental care, great variation exists in thefrequency of extrapair paternity. Several hypotheses have beenproposed to account for this variation. We tested the incompleteknowledge hypothesis, which states that females are constrainedin their knowledge of male quality and that this influencestheir willingness to engage in extrapair copulations (EPC).By selective removal and release of female pied flycatchersFicedula hypoleuca, we created a situation where females finallysettled with a social mate close to the site where a formersocial mate was breeding. According to the incomplete knowledgehypothesis, this would lower the threshold for females to seekextrapair copulations in cases where their former social matewas of higher quality than the one finally chosen. The hypothesiswas not supported because manipulation of female settlementdid not increase frequency of extrapair paternity, not evenin cases where the female nested close to the previous mateand the current mate apparently was of lower quality becausehe was younger and more dull colored. However, we found that when extrapair paternity did occur, the cuckolder tended tobe a familiar male (i.e., the female's initial social mate).     

Single-site mutations induce 3D domain swapping in the B1 domain of protein L from Peptostreptococcus magnus.

BACKGROUND: Thermodynamic and kinetic studies of the Protein L B1 domain (Ppl) suggest a folding pathway in which, during the folding transition, the first beta hairpin is formed while the second beta hairpin and the alpha helix are largely unstructured. The same mutations in the two beta turns have opposite effects on the folding and unfolding rates. Three of the four residues composing the second beta turn in Ppl have consecutive positive phi angles, indicating strain in the second beta turn. RESULTS: We have determined the crystal structures of the beta turn mutants G55A, K54G, and G15A, as well as a core mutant, V49A, in order to investigate how backbone strain affects the overall structure of Ppl. Perturbation of the hydrophobic interactions at the closed interface by the V49A mutation triggered the domain swapping of the C-terminal beta strand that relieved the strain in the second beta turn. Interestingly, the asymmetric unit of V49A contains two monomers and one domain-swapped dimer. The G55A mutation escalated the strain in the second beta turn, and this increased strain shifted the equilibrium toward the domain-swapped dimer. The K54G structure revealed that the increased stability is due to the reduction of strain in the second beta turn, while the G15A structure showed that increased strain alone is insufficient to trigger domain swapping. CONCLUSIONS: Domain swapping in Ppl is determined by the balance of two opposing components of the free energy. One is the strain in the second beta turn that favors the dimer, and the other is the entropic cost of dimer formation that favors the monomer. A single-site mutation can disrupt this balance and trigger domain swapping.     

Randomised,double blind,placebo controlled trial of penicillin V and amoxycillin in treatment of acute sinus infections in adults.

OBJECTIVES--To compare the effectiveness of penicillin V and amoxycillin with placebo in treatment of adult patients with acute sinusitis. DESIGN--Randomised, double blind, placebo controlled trial. SETTING--Norwegian general practice. SUBJECTS--130 adult patients with a clinical diagnosis of acute sinusitis confirmed by computed tomography. MAIN OUTCOME MEASURES--Subjective status after three and 10 days of treatment, difference in clinical severity score between day 0 and day 10 as evaluated by the general practitioner, difference in score from computed tomography on day 0 and day 10, and duration of sinusitis. RESULTS--Amoxycillin and penicillin V led to significantly faster and better recovery than placebo. By day 10, 71 patients receiving antibiotic treatment- (86%) considered themselves to be recovered or much better compared with 25 (57%) receiving placebo. The mean (95% confidence interval) reductions in clinical severity scores by day 10 were 5.4 (5.0 to 5.8) for penicillin V, 5.5 (4.9 to 6.0 for amoxycillin, and 3.4 (2.8 to 4.0) for placebo. For the antibiotic groups combined the number of patients with the greatest degree of improvement on computed tomography (scale 0-16)-that is, score 5-16 on day 10-was 31/83 (37%) compared with 10/44 (23%) receiving placebo. The median duration of the sinusitis was nine days in the amoxycillin group, 11 days in the penicillin V group, and 17 days in the placebo group. CONCLUSION--Penicillin V and amoxycillin are significantly more effective than placebo in the treatment of acute sinusitis.     

Cionin: a disulfotyrosyl hybrid of cholecystokinin and gastrin from the neural ganglion of the protochordate Ciona intestinalis

We have purified an acidic octapeptide from the neural ganglion of the protochordate Ciona intestinalis by a three-step procedure including C18 Sep-Pak fractionation, MonoQ ion-exchange chromatography, and C4 reversed-phase high-performance liquid chromatography. The purification was monitored by an immunoassay specific for the alpha-carboxyamidated COOH terminus common to the mammalian brain-gut hormones, cholecystokinin and gastrin. Automated Edman degradation revealed the sequence Asn-Tyr-Tyr-Gly-Trp-Met-Asp-Phe. In accordance with the high acidity of the peptide, amino acid analysis after cleavage with aminopeptidase M showed that both tyrosyl residues are sulfated. Hence, the structure is Asn-Tyr(SO3)-Tyr(SO3)-Gly-Trp-Met-Asp-Phe-NH2, as also confirmed by identity with the synthetic disulfated peptide in different chromatographic systems. The occurrence of two consecutively sulfated tyrosyl residues after a neutral residue challenges present concepts of consensus sites for tyrosyl sulfation. We conclude that the structure of the peptide, named cionin, suits that of a common ancestor for cholecystokinin and gastrin.     

Gas supersaturation in the cecal wall of mice due to bacterial CO2 production.

PCO2 in the lumen and serosa of cecum and jejunum was measured in mice. The anesthetic used was a fentanyl-fluanisone-midazolam mixture. PCO2 was recorded in vivo and postmortem. PCO2 was 409 +/- 32 Torr (55 +/- 4 kPa) in the cecal lumen and 199 +/- 22 Torr (27 +/- 3 kPa) on the serosa in normal mice. Irrigation of the cecum resulted in serosal and luminal PCO2 levels of 65-75 Torr. Cecal PCO2 was significantly lower in germ-free mice (65 +/- 5 Torr). Cecal PCO2 increased significantly after introduction of normal bacterial flora into germ-free mice. Introduction of bacterial monocultures into germ-free mice had no effect. After the deaths of the mice, cecal PCO2 increased rapidly in normal mice. The intestinal bacteria produced the majority of the cecal PCO2, and the use of tonometry in intestinal segments with a high bacterial activity should be interpreted with caution. We propose that serosal PCO2 levels >150-190 Torr (20-25 kPa) in the cecum of mice with a normal circulation may represent a state of gas supersaturation in the cecal wall.     

Binge Eating and Eating‐Related Cognitions and Behavior in Ethnically Diverse Obese Women

Objective: To examine binge eating and eating‐related cognitions and behavior in a sample of ethnically diverse women who are severely obese and seeking bariatric surgery. Research Methods and Procedures: Female bariatric surgery candidates (62 African Americans, 18 Latinas, 130 whites) completed questionnaires on binge eating and eating‐related cognitions and behavior and completed a structured clinical interview to confirm binge‐eating disorder diagnosis. Results: Ethnic minorities and whites did not differ in rates of binge‐eating disorder (26.3%), binges per week (M = 0.95), or dietary restraint. Ethnic minorities reported less disinhibition, and there was a trend to report less hunger awareness than whites. After controlling for BMI and education, ethnicity accounted for significant variance in disinhibition (4%; p < 0.01). Ethnic minorities were younger, became overweight at a later age, and were overweight for fewer years than whites. Discussion: Results suggest that ethnicity exerts an important influence on disinhibition and that ethnic differences are not caused by BMI or education. Findings point to the need to continue to investigate the role of ethnicity, binge eating, and disinhibition in severely obese women, so that culturally appropriate services can be provided.     

Metal accumulation in two contiguous eutrophic peri-urban lakes,Chivero and Manyame,Zimbabwe

Concentrations of aluminium, cadmium, chromium, cobalt, copper, iron, lead, nickel and zinc were determined in surface water, benthic sediments, and the gills, liver and stomach muscle tissues of Oreochromis niloticus and Clarias gariepinus in peri-urban lakes Chivero and Manyame, Zimbabwe. Five sites were sampled in each lake once per month in November 2015, February, May, August and November 2016. Pollution load index detected no metal contamination, whereas the geo-accumulation index reflected heavy to extreme sediment pollution, with Fe, Cd, Zn, Cr, Ni and Cu present in both lakes. Significant spatial temporal variations were detected for Al, Cr, Cu and Pb across sites within and between the two lakes. High Fe, Al and Cr concentrations in water and sediments in lakes Chivero and Manyame derive from geogenic background sources in addition to anthropogenic loads and intensity. Elevated concentrations of Al, Pb, Cu, Cd, Fe and Zn detected in gills, liver and stomach tissue of catfish corroborate concentrations in water and sediments, and pose the highest ecological and health risk for hydrobionts in lakes Chivero and Manyame. Contiguity of peri-urban lakes exposes them to similar threats, necessitating creative water management strategies, which ensure ecological continuity.     

Genotyping strategy matters when analyzing hypervariable major histocompatibility complex‐Experience from a passerine bird

Genotyping of classical major histocompatibility complex (MHC) genes is challenging when they are hypervariable and occur in multiple copies. In this study, we used several different approaches to genotype the moderately variable MHC class I exon 3 (MHCIe3) and the highly polymorphic MHC class II exon 2 (MHCIIβe2) in the bluethroat (Luscinia svecica). Two family groups (eight individuals) were sequenced in replicates at both markers using Ion Torrent technology with both a single‐ and a dual‐indexed primer structure. Additionally, MHCIIβe2 was sequenced on Illumina MiSeq. Allele calling was conducted by modifications of the pipeline developed by Sommer et al. (BMC Genomics, 14, 2013, 542) and the software AmpliSAS. While the different genotyping strategies gave largely consistent results for MHCIe3, with a maximum of eight alleles per individual, MHCIIβe2 was remarkably complex with a maximum of 56 MHCIIβe2 alleles called for one individual. Each genotyping strategy detected on average 50%–82% of all MHCIIβe2 alleles per individual, but dropouts were largely allele‐specific and consistent within families for each strategy. The discrepancies among approaches indicate PCR biases caused by the platform‐specific primer tails. Further, AmpliSAS called fewer alleles than the modified Sommer pipeline. Our results demonstrate that allelic dropout is a significant problem when genotyping the hypervariable MHCIIβe2. As these genotyping errors are largely nonrandom and method‐specific, we caution against comparing genotypes across different genotyping strategies. Nevertheless, we conclude that high‐throughput approaches provide a major advance in the challenging task of genotyping hypervariable MHC loci, even though they may not reveal the complete allelic repertoire.     

The effects of UV-B radiation on European heathland species

The effects of enhanced UV-B radiation on three examples of European shrub-dominated vegetation were studied in situ. The experiments were in High Arctic Greenland, northern Sweden and Greece, and at all sites investigated the interaction of enhanced UV-B radiation (simulating a 15% reduction in the ozone layer) with artificially increased precipitation. The Swedish experiment also involved a study of the interaction between enhanced UV-B radiation and elevated CO₂ (600 ppm). These field studies were supported by an outdoor controlled environment study in the United Kingdom involving modulated enhancement of UV-B radiation in combination with elevated CO₂ (700 ppm). Effects of the treatments on plant growth, morphology, phenology and physiology were measured. The effects observed were species specific, and included both positive and negative responses to the treatments. In general the negative responses to UV-B treatments of up to three growing seasons were small, but included reductions in shoot growth and premature leaf senescence. Positive responses included a marked increase in flowering in some species and a stimulation of some photosynthetic processes. UV-B treatment enhanced the drought tolerance of Pinus pinea and Pinus halepensis by increasing leaf cuticle thickness. In general, there were few interactions between the elevated CO₂ and enhanced UV-B treatments. There was evidence to suggest that although the negative responses to the treatments were small, damage may be increasing with time in some long-lived woody perennials. There was also evidence in the third year of treatments for effects of UV-B on insect herbivory in Vaccinium species. The experiments point to the necessity for long-term field investigations to predict the likely ecological consequences of increasing UV-B radiation.