Comparison of two methods used to analyse lipid peroxidation from Vaccinium myrtillus (L.) during snow removal, reacclimation and cold acclimation.

Malondialdehyde (MDA) concentration is a widely used method to analyse lipid peroxidation in biological material. In plant tissues, however, certain compounds (anthocyanins, carbohydrates) may interfere with measurements which may lead to an overestimation of the MDA levels. Two methods were compared for analysing lipid peroxidation, either uncorrected or corrected for interfering compounds. The comparison was performed in three separate experiments with respect to cold treatments (snow removal in winter, reacclimation in summer and cold acclimation in autumn) in bilberry (Vaccinium myrtillus L.). During winter and autumn the methods seem to measure different compounds, but during active growth in the summer the difference between the methods was less. This is obviously due to carbohydrates which act as cryoprotectants and increase in concentration during cold acclimation as well as due to the anthocyanins. It is thus suggested that the validity of the uncorrected method to measure MDA and thereby lipid peroxidation is best in plant tissue which is in an active growth state.     

Moving through Life-Space Areas and Objectively Measured Physical Activity of Older People

Objectives

Physical activity–an important determinant of health and function in old age–may vary according to the life-space area reached. Our aim was to study how moving through greater life-space areas is associated with greater physical activity of community-dwelling older people. The association between objectively measured physical activity and life-space area reached on different days by the same individual was studied using one-week longitudinal data, to provide insight in causal relationships.

Methods

One-week surveillance of objectively assessed physical activity of community-dwelling 70–90-year-old people in central Finland from the “Life-space mobility in old age” cohort substudy (N = 174). In spring 2012, participants wore an accelerometer for 7 days and completed a daily diary including the largest life-space area reached (inside home, outside home, neighborhood, town, and beyond town). The daily step count, and the time in moderate (incl. walking) and low activity and sedentary behavior were assessed. Differences in physical activity between days on which different life-space areas were reached were tested using Generalized Estimation Equation models (within-group comparison).

Results

Participants’ mean age was 80.4±4.2 years and 63.5% were female. Participants had higher average step counts (p < .001) and greater moderate and low activity time (p < .001) on days when greater life-space areas were reached, from the home to the town area. Only low activity time continued to increase when moving beyond the town.

Conclusion

Community-dwelling older people were more physically active on days when they moved through greater life-space areas. While it is unknown whether physical activity was a motivator to leave the home, intervention studies are needed to determine whether facilitation of daily outdoor mobility, regardless of the purpose, may be beneficial in terms of promoting physical activity.     

Reddish spring colouring of deciduous leaves: a sign of ecotype?

Several deciduous woody plant species produce anthocyanins during leaf development in spring and again during leaf senescence in autumn. The leaves of Betula pendula Roth (silver birch) commonly exhibit transient reddening in juvenile leaves under northern growing conditions, with the intensity of the red colour varying among individual trees. The objective of our study was to test the hypothesis that the accumulation of foliar anthocyanins during spring in leaves of B. pendula is an ecotypic response. Chlorophyll fluorescence ratio (Fv/Fm), leaf reflectance and anthocyanin concentrations were measured, in relation to phenology in spring, summer and autumn from birches used for landscaping with either red or green-emergent leaves. The results suggest that (1) the trees with green- or red-emergent juvenile leaves represent different populations, and (2) that the red-emergent leaves senesced earlier, indicating that (3) trees with red-emerging leaves belong to a more northern ecotype than the trees with green-emerging leaves. The role of anthocyanin synthesis in a northern radiation environment is discussed.     

Overwintering stress of Vaccinium vitis-idaea in the absence of snow cover

A snow manipulation experiment aimed to assess risks of direct freezing injury, freeze-induced dehydration and winter desiccation in the absence of snow cover on lingonberry (Vaccinium vitis-idaea). Frames with sheet-plastic sides and removable lids were used in this experiment for two purposes: to prevent accumulation of snow in mid-winter and to provide extra heat during early spring. Leaves were analyzed for frost hardiness, tissue water content and osmotic concentrations, and photoinhibition (Fv/Fm) during the period from the 10th of February to the 7th of April. The natural snow accumulation was low indicated by a minor difference in minimum temperatures between the frame treatment and naturally snow-covered plots. The heating effect of the frames started gradually at the end of February along with increasing solar elevation angles, and was highest at the beginning of April. Frost hardiness peaked in March as a consequence of cold periods, but it was practically lost by the beginning of April. Tissue water content decreased gradually at first, becoming greatly decreased later due to the extra heat. In accordance, the tissue osmotic concentrations increased first gradually, followed by a dramatic increase. Photoinhibition increased uniformly with increasing solar radiation, but at the end showed a sharp increment within a few days, obviously also indicating the effect of heating. It was concluded that neither lethal freezing stress nor significant freeze-induced dehydration occurred during the experiment. However, plants that overwintered without snow suffered from severe winter desiccation injuries due to the combination of solar heat and frozen soil. Although the desiccation stress was possibly a lethal factor, it was preceded by long-term and continued photoinhibition. It was concluded that during overwintering, chamaephyte species may suffer from both freezing and winter desiccation in the absence of protecting snow cover. However, during mild winters provided by climatic change scenarios, the risk of winter desiccation will be more probable. In relation to the future climate, it was concluded that winter desiccation and photoinhibition may develop gradually during a snowless winter and would, even if they did not reach a lethal level by themselves, possibly reduce frost hardiness.     

Induction of Gliotoxin Secretion in Aspergillus fumigatus by Bacteria-Associated Molecules

Aspergillus fumigatus is the most common causative agent of mold diseases in humans, giving rise to life-threatening infections in immunocompromised individuals. One of its secreted metabolites is gliotoxin, a toxic antimicrobial agent. The aim of this study was to determine whether the presence of pathogen-associated molecular patterns in broth cultures of A. fumigatus could induce gliotoxin production. Gliotoxin levels were analyzed by ultra-performance liquid chromatography and mass spectrometry. The presence of a bacteria-derived lipopolysaccharide, peptidoglycan, or lipoteichoic acid in the growth media at a concentration of 5 μg/ml increased the gliotoxin concentration in the media by 37%, 65%, and 35%, respectively. The findings reveal a correlation between the concentrations of pathogen-associated molecular patterns and gliotoxin secretion. This shows that there is a yet uncharacterized detection system for such compounds within fungi. Inducing secondary metabolite production by such means in fungi is potentially relevant for drug discovery research. Our results also give a possible explanation for the increased virulence of A. fumigatus during bacterial co-infection, one that is important for the transition from colonization to invasiveness in this pulmonary disease.     

A confirmatory analysis of malachite green residues in rainbow trout with liquid chromatography-electrospray tandem mass spectrometry

A quantitative liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed for the determination of malachite green (MG) and its metabolite leucomalachite green (LMG) in fish. Residues were extracted with an acetonitrile-acetate buffer and purified using the automated solid-phase extraction (ASPEC). Residues were analyzed with a reversed-phase LC-MS/MS using a positive-ion electrospray ionisation (ESI). Isotope-labelled leucomalachite green (LMG-D5) was used as an internal standard for the quantification of LMG residues. The related dye, brilliant green (BG) was used as an instrumental standard. Identification and quantification of analytes were based on the ion transitions monitored by multiple reaction monitoring (MRM). The decision limit (CCalpha) for MG and LMG was 0.13 and 0.16 microgkg(-1). The respective detection capabilities (CCbeta) were 0.22 and 0.27 microgkg(-1). The absolute recovery (repeatability SD(r)) was in the range of 58-65% (7.8-11.2%) for MG and 59-68% (9.7-16.9%) for LMG. LMG was quantified also based on the internal standard, giving a recovery (repeatability SD(r)) of 103-110% (4.8-9.3%). The method was further evaluated by analyzing a total of 34 fish residue monitoring samples, of which eight samples were found to be non-compliant containing low residues of LMG.     

Genetic diversity in clinical isolates of Mycobacterium avium complex from Guinea-Bissau, West Africa

Isolates of Mycobacterium avium complex (MAC) were cultured from sputum samples obtained from patients in Guinea-Bissau, West Africa. Twenty-eight isolates hybridising with MAC probe (AccuProbe) were further characterised by different molecular techniques: hybridisation with species-specific probes (AccuProbe) for M. avium and M. intracellulare, partial sequencing of 16S rRNA gene and PCR detection of the DT1-DT6 sequences and the macrophage-induced gene (mig). Only one of the 28 isolates reacted with the M. avium probe and four with the M. intracellulare probe. Two isolates expressed the DT1 sequence, and three the DT6. The mig was detected in 18 (64%) of the isolates. Sequencing of 16S rRNA had the greatest discriminative power of the typing methods applied, without strong correlation with any other technique. Clinical MAC isolates from Guinea-Bissau demonstrated a wide genetic diversity among the members of M. avium complex that might reflect on biotope variation.     

Optimization of Protein Extraction from <Emphasis Type="Italic">Hypericum perforatum</Emphasis> Tissues and Immunoblotting Detection of Hyp-1 at Different Stages of Leaf Development

Sample preparation is crucial for obtaining high-quality proteins for the purpose of electrophoretic separation and further analysis from tissues that contain high levels of interfering compounds. Hypericum perforatum is a medicinal plant that contains high amounts of phenolic compounds, of which hypericins, hyperforins, and flavonoids contribute to the antidepressant activities of the plant. This study focuses on obtaining optimized amounts of high-quality proteins from H. perforatum, which are suitable for electrophoretic analyses. From the tested protein extraction solutions, sodium borate buffers at pH 9 and 10 gave the best protein yields from mature H. perforatum leaves. With these buffers, relatively high protein yields could also be obtained from roots, stems, and flower buds. The protein extracts of all organs were well resolved in SDS-PAGE after an efficient removal of non-protein contaminants with PVPP, phenol extraction, and methanolic ammonium acetate precipitation. The method was suitable for high-quality protein extraction also from other tested species of genus Hypericum. The applicability of the protocol for immunoblotting was demonstrated by detecting Hyp-1 in H. perforatum leaves at different stages of development. Hyp-1, which has been suggested to attend to the biosynthesis of hypericin, accumulated in high amounts in H. perforatum leaves at mature stage.     

Mobility Modification Alleviates Environmental Influence on Incident Mobility Difficulty among Community-Dwelling Older People: A Two-Year Follow-Up Study

BackgroundEnvironmental barriers increase risk for mobility difficulties in old age. Mobility difficulty is preceded by a phase where people try to postpone a difficulty through mobility modification. We studied whether perceived environmental mobility barriers outdoors correlate with mobility modification and mobility difficulty, predict development of mobility difficulty over a two-year follow-up, and whether mobility modification alleviates the risk for difficulty.MethodsAt baseline, 848 people aged 75–90 were interviewed face-to-face. Telephone follow-up interviews were conducted one (n = 816) and two years (n = 761) later. Environmental barriers to mobility were self-reported using a15-item structured questionnaire at baseline, summed and divided into tertiles (0, 1 and 2 or more barriers). Mobility difficulty was assessed as self-reported ability to walk 2 km at all assessment points and categorized into ‘no difficulty’, ‘no difficulty but mobility modifications’ (reducing frequency, stopping walking, using an aid, slowing down or resting during the performance) and ‘difficulty’.ResultsAt baseline, 212 participants reported mobility modifications and 356 mobility difficulties. Those reporting one or multiple environmental barriers had twice the odds for mobility modifications and up to five times the odds for mobility difficulty compared to those reporting no environmental barriers. After multiple adjustments for health and functioning, reporting multiple environmental barriers outdoors continued to predict the development of incident mobility difficulty over the two-year follow-up. Mobility modifications attenuated the association.ConclusionFor older people who successfully modify their performance, environmental influence on incident mobility difficulty can be diminished. Older people use mobility modification to alleviate environmental press on mobility.     

Movement of generative cell and vegetative nucleus in tobacco pollen tubes is dependent on microtubule cytoskeleton but independent of the synthesis of callose plugs

The role of microtubules (MTs) in vegetative nucleus (VN) and generative cell (GC) transport was investigated by comparing VN and GC distribution with callose plug formation in tobacco pollen grains germinated and grown for 12 h with the plant-specific anti-MT drug oryzalin. The VN-GC complex or VN alone was located close to the tube tip in 100% of controls, but in only 5% of oryzalin-treated tubes. Instead, in 38% of oryzalin tubes, the complex or VN occurred close to the last-formed callose plug; in 40% between or in the middle of plugs; and in 17%, in or near the grain. An aberrant microfilament (MF) cytoskeleton was revealed by expression of a green fluorescent protein-talin fusion protein in living oryzalin-treated tubes. The abnormal MF structures probably resulted from the absence of MTs and impaired - or were a consequence of - VN and GC movement into the tube tip. In oryzalin tubes with several callose plugs, the VN and GC could be in or near the grain, indicating that callose plug synthesis is not dependent on the movement of VN and GC into the tube. VN and GC movement and callose plug formation are apparently independent events, in which the transport of the VN-GC complex must precede callose plug synthesis. Maintenance of the correct developmental program requires an intact MT cytoskeleton, otherwise no fertile pollen tubes are formed.