“A cleaner break”: Genetic divergence between geographic groups and sympatric phenotypes revealed in ballan wrasse (Labrus bergylta)

Capture and long‐distance translocation of cleaner fish to control lice infestations on marine salmonid farms has the potential to influence wild populations via overexploitation in source regions, and introgression in recipient regions. Knowledge of population genetic structure is therefore required. We studied the genetic structure of ballan wrasse, a phenotypically diverse and extensively used cleaner fish, from 18 locations in Norway and Sweden, and from Galicia, Spain, using 82 SNP markers. We detected two very distinct genetic groups in Scandinavia, northwestern and southeastern. These groups were split by a stretch of sandy beaches in southwest Norway, representing a habitat discontinuity for this rocky shore associated benthic egg‐laying species. Wrasse from Galicia were highly differentiated from all Scandinavian locations, but more similar to northwestern than southeastern locations. Distinct genetic differences were observed between sympatric spotty and plain phenotypes in Galicia, but not in Scandinavia. The mechanisms underlying the geographic patterns between phenotypes are discussed, but not identified. We conclude that extensive aquaculture‐mediated translocation of ballan wrasse from Sweden and southern Norway to western and middle Norway has the potential to mix genetically distinct populations. These results question the sustainability of the current cleaner fish practice.     

Regulation of threonine biosynthesis in barley seedlings (Hordeum vulgare L.)

Homoserine kinase was purified 700-fold by fractional ammonium sulfate precipitation, heat treatment, CM-Sephadex C-50 and DEAE-Sephadex A-50 ion exchange chromatography, and Sephadex G-100 gel filtration. The reaction products O-phosphohomoserine and ADP were the only compounds which caused considerable inhibition of homoserine kinase activity. Product inhibition studies showed non-competitive inhibition between ATP and O-phosphohomoserine and between homoserine and O-phosphohomoserine, and competitive inhibition between ATP and ADP. ADP showed non-competitive inhibition versus homoserine at suboptimal concentrations of ATP. At saturating concentrations of ATP no effect of ADP was observed. The homoserine kinase activity was negligible in the absence of K⁺ and the K_m value for K⁺ was observed to be 4.3 mmol l^–1. A non-competitive pattern was observed with respect to the substrates homoserine and ATP. Threonine synthase in the first green leaf of 6-day-old barley seedlings was partially purified 15-fold by ammonium sulfate fractionation and Sephadex G-100 gel chromatography. Threonine synthase was shown to require pyridoxal 5-phosphate as coenzyme for optimum activity and the enzyme was strongly activated by S-adenosyl-L-methionine. The optimum pH for threonine synthase activity was 7 to 8.Abbreviations PLP Pyridoxal 5-phosphate - SAM S-adenosyl-L-methionine - HSP O-phosphohomoserine     

Characterization of Cytomegalovirus Disease in Solid Organ Transplant Recipients by Markers of Inflammation in Plasma

Background

While several studies have examined the general inflammatory responses in relation to cytomegalovirus infection, the identification of the various inflammatory mediators as well as their relative importance is far from clear.

Patients and Methods

Solid organ recipients enrolled in an international multicenter trial of cytomegalovirus disease treatment (the VICTOR study) were analyzed (n = 289) (ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00431353","term_id":"NCT00431353"}}NCT00431353). Plasma markers of inflammation and endothelial cell activation were assessed at baseline by enzyme immunoassays.

Results

The major findings were: (i) Plasma levels of the CXC-chemokine interferon-inducible protein-10 (P<0.001) and C-reactive protein (P = 0.046) were independently associated with the presence of cytomegalovirus DNAemia above lower level of quantification. (ii) High levels of CC-chemokine ligand 21 (P = 0.027) and pentraxin 3 (P = 0.033) were independently associated with tissue invasive cytomegalovirus disease as opposed to cytomegalovirus syndrome.

Conclusion

Our findings illustrate the complex interaction between cytomegalovirus and the immune system, involving a wide range of inflammatory mediators that could be associated to disease manifestations in cytomegalovirus related disease.     

Use of Real-Time Quantitative PCR for the Analysis of φLC3 Prophage Stability in Lactococci

Bacteriophages are a common and constant threat to proper milk fermentation. It has become evident that lysogeny is widespread in lactic acid bacteria, and in this work the temperate lactococcal bacteriophage LC3 was used as a model to study prophage stability in lactococci. The stability was analyzed in six LC3 lysogenic Lactococcus lactis subsp. cremoris host strains when they were growing at 15 and 30°C. In order to perform these analyses, a real-time PCR assay was developed. The stability of the LC3 prophage was found to vary with the growth phase of its host L. lactis IMN-C1814, in which the induction rate increased during the exponential growth phase and reached a maximum level when the strain was entering the stationary phase. The maximum spontaneous induction frequency of the LC3 prophage varied between 0.32 and 9.1% (28-fold) in the six lysogenic strains. No correlation was observed between growth rates of the host cells and the spontaneous prophage induction frequencies. Furthermore, the level of extrachromosomal phage DNA after induction of the prophage varied between the strains (1.9 to 390%), and the estimated burst sizes varied up to eightfold. These results show that the host cells have a significant impact on the lytic and lysogenic life styles of temperate bacteriophages. The present study shows the power of the real-time PCR technique in the analysis of temperate phage biology and will be useful in work to reveal the impact of temperate phages and lysogenic bacteria in various ecological fields.     

Multiplex real-time PCR for monitoring Heterobasidion annosum colonization in Norway spruce clones that differ in disease resistance

A multiplex real-time PCR assay was developed to monitor the dynamics of the Picea abies-Heterobasidion annosum pathosystem. Tissue cultures and 32-year-old trees with low or high resistance to this pathogen were used as the host material. Probes and primers were based on a laccase gene for the pathogen and a polyubiquitin gene for the host. The real-time PCR procedure was compared to an ergosterol-based quantification method in a tissue culture experiment, and there was a strong correlation (product moment correlation coefficient, 0.908) between the data sets. The multiplex real-time PCR procedure had higher resolution and sensitivity during the early stages of colonization and also could be used to monitor the host. In the tissue culture experiment, host DNA was degraded more rapidly in the clone with low resistance than in the clone with high resistance. In the field experiment, the lesions elicited were not strictly proportional to the area colonized by the pathogen. Fungal colonization was more restricted and localized in the lesion in the clone with high resistance, whereas in the clone with low resistance, the fungus could be detected until the visible end of the lesion. Thus, the real-time PCR assay gives better resolution than does the traditionally used lesion length measurement when screening host clones for resistance.     

Identification of the hydroxyl radical and other reactive oxygen species in human neutrophil granulocytes exposed to a fragment of the amyloid beta peptide

A fragment of the amyloid beta protein, βA(25-35), was investigated for its effect on production of reactive oxygen species (ROS) in human neutrophil granulocytes. The formation and identification of ROS were examined by using a 2',7'-dichlorofluorescin (DCF) fluorescence assay, a luminol chemiluminescence assay, electron paramagnetic resonance (EPR) spectroscopy with DEPMPO as a spin trap, and hydroxylation of 4-hydroxybenzoate (4-HBA). The DCF assay showed that βA(25-35) stimulated formation of ROS in a concentration and time dependent manner. The inverted peptide, βA(35-25), gave no response. Also, luminol-amplified chemiluminescence was stimulated by βA(25-35). Incubation with diethyldithiocarbamate (a superoxide dimustase inhibitor) and salicylhydroxamate (SHA; a myeloperoxidase inhibitor) reduced the chemiluminescence. This indicates that hypochlorous acid (HOCl) is formed after exposure to βA(25-35). The EPR spectra indicated a concentration dependent formation of superoxide ( O 2 • - ) - and hydroxyl ( •OH)- radicals. Hydroxylation of 4-HBA to 3,4,-dihydroxybenzoate confirmed production of •OH. This response was attenuated by SHA, indicating involvement of HOCl in formation of •OH. The DCF fluorescence was inhibited with U0126 (an extracellular signal regulated protein kinase (ERK) inhibitor). Further analysis with western blot confirmed phosphorylation of ERK1/2 after exposure to βA(25-35). The phospholipase A 2 (PLA 2 ) inhibitor 7,7-dimethyl-(5Z,8Z)-eicosadienoic acid, and diphenyleneiodonium, which inhibits the NADPH oxidase, also led to a reduction of the DCF fluorescence. The present findings indicate that βA(25-35) stimulates the NADPH oxidase by activating the ERK pathway and PLA 2 . Production of O 2 • - can lead to HOCl and further formation of •OH, which both have a cytotoxic potential.     

Cost-Effectiveness of Peer Counselling for the Promotion of Exclusive Breastfeeding in Uganda

Background

Community based breastfeeding promotion programmes have been shown to be effective in increasing breastfeeding prevalence. However, there is limited data on the cost-effectiveness of these programmes in sub-Saharan Africa. This paper evaluates the cost-effectiveness of a breastfeeding promotion intervention targeting mothers and their 0 to 6 month old children.

Methods

Data were obtained from a community randomized trial conducted in Uganda between 2006–2008, and supplemented with evidence from several studies in sub-Saharan Africa. In the trial, peer counselling was offered to women in intervention clusters. In the control and intervention clusters, women could access standard health facility breastfeeding promotion services (HFP). Thus, two methods of breastfeeding promotion were compared: community based peer counselling (in addition to HFP) and standard HFP alone. A Markov model was used to calculate incremental cost-effectiveness ratios between the two strategies. The model estimated changes in breastfeeding prevalence and disability adjusted life years. Costs were estimated from a provider perspective. Uncertainty around the results was characterized using one-way sensitivity analyses and a probabilistic sensitivity analysis.

Findings

Peer counselling more than doubled the breastfeeding prevalence as reported by mothers, but there was no observable impact on diarrhoea prevalence. Estimated incremental cost-effectiveness ratios were US$68 per month of exclusive or predominant breastfeeding and U$11,353 per disability adjusted life year (DALY) averted. The findings were robust to parameter variations in the sensitivity analyses

Conclusions

Our strategy to promote community based peer counselling is unlikely to be cost-effective in reducing diarrhoea prevalence and mortality in Uganda, because its cost per DALY averted far exceeds the commonly assumed willingness-to-pay threshold of three times Uganda’s GDP per capita (US$1653). However, since the intervention significantly increases prevalence of exclusive or predominant breastfeeding, it could be adopted in Uganda if benefits other than reducing the occurrence of diarrhoea are believed to be important.     

Secondary buds in Scots pine trees infested with <Emphasis Type="Italic">Gremmeniella abietina</Emphasis>

In winter 2000–2001, there was a serious outbreak of Gremmeniella abietina Morelet in southeastern Norway. During the outbreak, we noted that injured Scots pine trees (Pinus sylvestris L.) developed secondary buds in response to the fungus attack, and we decided to study the relationship between injury, appearance of secondary buds and recovery of the trees thereafter. For this purpose, 143 trees from 10 to 50 years of age were chosen and grouped into crown density classes. Injury was assessed in detail, and buds were counted before bud burst in the spring of 2002. In addition, a subset of 15 trees was followed through the summer of 2002 to assess recovery. All injured trees developed secondary buds, with a clear overweight of dormant winter buds in proportion to interfoliar buds. Healthy control trees did not develop secondary buds at all. The secondary buds appeared predominantly on the injured parts of the tree; interfoliar buds in particular developed just beneath the damaged tissue. Most of the secondary buds died during the winter of 2001–2002, mainly because the fungus continued to spread after the first outbreak. Many of the remaining buds developed shoots with abnormal growth during the summer. Secondary buds may help trees to recover from Gremmeniella attacks, but this strategy may fail when the fungus continues to grow and injure the newly formed buds and shoots.