Docosahexaenoic Acid Status in Pregnancy Determines the Maternal Docosahexaenoic Acid Status 3-, 6- and 12 Months Postpartum. Results from a Longitudinal Observational Study

Background

Essential fatty acid status as well as docosahexaenoic acid (DHA, 22:6n-3) declines during pregnancy and lactation. As a result, the DHA status may not be optimal for child development and may increase the risk for maternal postpartum depression. The objective of this study was to assess changes in the maternal fatty acid status from pregnancy to 12 months postpartum, and to study the impact of seafood consumption on the individual fatty acid status.

Methods

Blood samples and seafood consumption habits (gestation week 28, and three-, six- and 12 months postpartum) were collected in a longitudinal observational study of pregnant and postpartum women (n = 118). Multilevel linear modeling was used to assess both changes over time in the fatty acid status of red blood cells (RBC), and in the seafood consumption.

Results

Six fatty acids varied the most (>80%) across the four time points analyzed, including the derivative of the essential α-linoleic acid (ALA, 18:3n-3), DHA; the essential linoleic acid (LA, 18:2 n-6); and the LA derivative, arachidonic acid (AA, 20:4n-6). Over all, a large variation in individuals’ DHA- and AA status was observed; however, over the 15-month study period only small inter-individual differences in the longitudinal trajectory of DHA- and AA abundance in the RBC were detected. The median intake of seafood was lower than recommended. Regardless, the total weekly frequency of seafood and eicosapentaenoic acid (EPA, 20:5n-3)/DHA-supplement intake predicted the maternal level of DHA (μg/g RBC).

Conclusion

The period of depletion of the maternal DHA status during pregnancy and lactation, seem to turn to repletion from about six months postpartum towards one year after childbirth, irrespective of RBC concentration of DHA during pregnancy. Seafood and EPA/DHA-supplement intake predicted the DHA levels over time.

Trial Registration

www.helseforskning.etikkom.no 2009/570/REC, project number: 083.09     

An easy-to-use simulation program demonstrates variations in bacterial cell cycle parameters depending on medium and temperature

Many studies are performed on chromosome replication and segregation in Escherichia coli and other bacteria capable of complex replication with C phases spanning several generations. For such investigations an understanding of the replication patterns, including copy numbers of origins and replication forks, is crucial for correct interpretation of the results.Flow cytometry is an important tool for generation of experimental DNA distributions of cell populations. Here, a Visual Basic based simulation program was written for the computation of theoretical DNA distributions for different choices of cell cycle parameters (C and D phase durations, doubling time etc). These cell cycle parameters can be iterated until the best fit between the experimental and theoretical DNA histograms is obtained. The Excel file containing the simulation software is attached as supporting information.Cultures of Escherichia coli were grown at twelve different media and temperature conditions, with following measurements by flow cytometry and simulation of the DNA distributions. A good fit was found for each growth condition by use of our simulation program. The resulting cell cycle parameters displayed clear inter-media differences in replication patterns, but indicated a high degree of temperature independence for each medium. The exception was the poorest medium (acetate), where the cells grew with overlapping replication cycles at 42 °C, but without at the lower temperatures.We have developed an easy-to-use tool for determination of bacteria's cell cycle parameters, and consequently the cells' chromosome configurations. The procedure only requires DNA distribution measurements by flow cytometry. Use of this simulation program for E. coli cultures shows that even cells growing quite slowly can have overlapping replication cycles. It is therefore always important not only to assume cells' replication patterns, but to actually determine the cell cycle parameters when changing growth conditions.     

Fate of Francisella noatunensis, a pathogen of Atlantic cod Gadus morhua, in blue mussels Mytilus edulis

Francisellosis, caused by the bacterium Francisella noatunensis, is one of the most severe diseases affecting farmed cod, and has caused great economic loss for the cod farming industry in Norway. We studied the fate of F. noatunensis in the marine environment, focusing on the role of blue mussels. In experimental challenges, waterborne F. noatunensis was rapidly filtered by the blue mussel and transported to the digestive diverticulae. The bacteria passed through the entire digestive system. Intraperitoneal injection of cod with suspensions prepared from faeces collected from challenged mussels resulted in the development of francisellosis in the recipients, demonstrating that some bacteria were alive and infective when shed in mussel faeces. Bacterial clearance from the mussels was relatively fast, and no evidence was found, suggesting that the bacterium is capable of persisting or multiplying in the mussel tissues. A cohabitation experiment with cod and mussels previously exposed to F. noatunensis did not lead to infection in cod. A direct transmission from contaminated mussels to cod was thus not demonstrated; however, faeces particles with infective bacteria may play a role in the transmission of the bacterium in marine food chains.     

Recreating semi-natural grasslands: A comparison of four methods

Semi-natural grasslands and their species and populations are declining rapidly throughout Europe, bringing about a need for successful vegetation recreation methods. To maintain biodiversity and ecological services of semi-natural grasslands, we need more knowledge on the relative performance of different recreation methods. In a replicated experiment in western Norway, we evaluated two hay transfer methods (hard or light raking of local hay), sowing of local seeds and natural regeneration for recreating semi-natural grassland in a road verge. We compared treated trial plots with their respective donor plots (where hay and seeds were harvested) for three successive years by evaluating vegetation cover, species richness and species transfer rates, and vegetation dynamics analysed by Bray–Curtis compositional dissimilarity (BC) and GNMDS (Global Non-Metric Multidimensional Scaling) ordination. Vegetation cover at the trial site exceeded that of donor sites in three years. Transfer rates of common species were high for seed sowing and both hay transfer procedures. Species composition in trial plots for all three treatments became significantly more similar to donor plots, but was still relatively dissimilar after three years. Natural regeneration showed a different temporal pattern and also had a higher successional rate. The species composition of the other treatments followed the same trajectory toward the donor sites as revealed by GNMDS. We found relatively small differences between the two hay transfer methods and seed sowing. Transfer of local hay therefore appears to be a successful method of establishing local species when recreating semi-natural grasslands, and is generally cheaper than using commercial local seed mixtures.     

Monocarboxylate Transporters 1–4 in NSCLC: MCT1 Is an Independent Prognostic Marker for Survival

Introduction

Monocarboxylate transporters (MCTs) 1–4 are lactate transporters crucial for cancers cells adaption to upregulated glycolysis. Herein, we aimed to explore their prognostic impact on disease-specific survival (DSS) in both cancer and tumor stromal cells in NSCLC.

Methods

Tissue micro arrays (TMAs) were constructed, representing both cancer and stromal tumor tissue from 335 unselected patients diagnosed with stage I–IIIA NSCLC. Immunohistochemistry was used to evaluate the expression of MCT1-4.

Results

In univariate analyses; ↓MCT1 (P = 0.021) and ↑MCT4 (P = 0.027) expression in cancer cells, and ↑MCT1 (P = 0.003), ↓MCT2 (P = 0.006), ↓MCT3 (P = 0.020) expression in stromal cells correlated significantly with a poor DSS. In multivariate analyses; ↓MCT1 expression in cancer cells (HR: 1.9, CI 95%: 1.3–2.8, P = 0.001), ↓MCT2 (HR: 2.4, CI 95%: 1.5–3.9, P<0.001), ↓MCT3 (HR: 1.9, CI 95%: 1.1–3.5, P = 0.031) and ↑MCT1 expression in stromal cells (HR: 1.7, CI 95%: 1.1–2.7, P = 0.016) were significant independent poor prognostic markers for DSS.

Conclusions

We provide novel information of MCT1 as a candidate marker for prognostic stratification in NSCLC. Interestingly, MCT1 shows diverging, independent prognostic impact in the cancer cell and stromal cell compartments.     

Genome sequence of the Arctic methanotroph Methylobacter tundripaludum SV96

Methylobacter tundripaludum SV96^T (ATCC BAA-1195) is a psychrotolerant aerobic methane-oxidizing gammaproteobacterium (Methylococcales, Methylococcaceae) living in High Arctic wetland soil. The strain was isolated from soil harvested in July 1996 close to the settlement Ny-Ålesund, Svalbard, Norway (78°56′N, 11°53′E), and described as a novel species in 2006. The genome includes pmo and pxm operons encoding copper membrane monooxygenases (Cu-MMOs), genes required for nitrogen fixation, and the nirS gene implicated in dissimilatory nitrite reduction to NO but no identifiable inventory for further processing of nitrogen oxides. These genome data provide the basis to investigate M. tundripaludum SV96, identified as a major player in the biogeochemistry of Arctic environments.     

Telomere Length and Long-Term Endurance Exercise: Does Exercise Training Affect Biological Age? A Pilot Study

Background

Telomeres are potential markers of mitotic cellular age and are associated with physical ageing process. Long-term endurance training and higher aerobic exercise capacity (VO_2max) are associated with improved survival, and dynamic effects of exercise are evident with ageing. However, the association of telomere length with exercise training and VO_2max has so far been inconsistent. Our aim was to assess whether muscle telomere length is associated with endurance exercise training and VO_2max in younger and older people.

Methods

Twenty men; 10 young (22–27 years) and 10 old (66–77 years), were studied in this cross-sectional study. Five out of 10 young adults and 5 out of 10 older were endurance athletes, while other halves were exercising at a medium level of activity. Mean telomere length was measured as telomere/single copy gene-ratio (T/S-ratio) using quantitative real time polymerase chain reaction. VO_2max was measured directly running on a treadmill.

Results

Older endurance trained athletes had longer telomere length compared with older people with medium activity levels (T/S ratio 1.12±0.1 vs. 0.92±0.2, p = 0.04). Telomere length of young endurance trained athletes was not different than young non-athletes (1.47±0.2 vs. 1.33±0.1, p = 0.12). Overall, there was a positive association between T/S ratio and VO_2max (r = 0.70, p = 0.001). Among endurance trained athletes, we found a strong correlation between VO_2max and T/S ratio (r = 0.78, p = 0.02). However, corresponding association among non-athlete participants was relatively weak (r = 0.58, p = 0.09).

Conclusion

Our data suggest that VO_2max is positively associated with telomere length, and we found that long-term endurance exercise training may provide a protective effect on muscle telomere length in older people.     

The DnaA Protein Is Not the Limiting Factor for Initiation of Replication in Escherichia coli

The bacterial replication cycle is driven by the DnaA protein which cycles between the active ATP-bound form and the inactive ADP-bound form. It has been suggested that DnaA also is the main controller of initiation frequency. Initiation is thought to occur when enough ATP-DnaA has accumulated. In this work we have performed cell cycle analysis of cells that contain a surplus of ATP-DnaA and asked whether initiation then occurs earlier. It does not. Cells with more than a 50% increase in the concentration of ATP-DnaA showed no changes in timing of replication. We suggest that although ATP-DnaA is the main actor in initiation of replication, its accumulation does not control the time of initiation. ATP-DnaA is the motor that drives the initiation process, but other factors will be required for the exact timing of initiation in response to the cell’s environment. We also investigated the in vivo roles of datA dependent DnaA inactivation (DDAH) and the DnaA-binding protein DiaA. Loss of DDAH affected the cell cycle machinery only during slow growth and made it sensitive to the concentration of DiaA protein. The result indicates that compromised cell cycle machines perform in a less robust manner.