Diatoms in peat - Dominant producers in a changing environment?

Changes in hydrology and temperature can induce rapid changes in boreal wetland ecosystems. Factors such as hydrosere, permafrost, climate and human interference may disturb the prevailing mire vegetation, whereby a new dominant assemblage can develop. At the transition from one vegetation type to another, the old vegetation may be suppressed, die out or start to decay, and some time may pass until a new mire vegetation is fully established. Here, we demonstrate that diatoms may thrive during such transitions, creating isolated and shallow peat layers with significantly elevated biogenic silica content. Biogenic silica and other nutrients that would otherwise be lost during mineralization in runoff are in this way retained in the ecosystem. Our results imply that silica storage originating from diatoms can be expected to increase in today's rapidly changing boreal wetlands. The impacts on transport of Si through boreal watersheds are currently unknown.     

Study of grain cell wall structures by microscopic analysis with four different staining techniques

Four different grain cell wall staining techniques were compared. Two techniques specifically detected arabinoxylan (AX). The first technique used a xylanase probe, while the other one was based on immunolabeling of AX using monoclonal antibodies. The two other staining techniques, one based on Calcofluor and the other on immunolabeling using monoclonal antibodies, stained mixed-linkage β-glucan. Cell walls of wheat, barley, oat and rye grains, differing both in content and location of AX and β-glucan, were examined. The staining methods were complementary to each other in revealing the location and distribution of the major cereal dietary fiber components AX and β-glucan in the different grains. AX was mostly concentrated in nucellar epidermis and aleurone cells, whereas β-glucan was concentrated more in subaleurone cells. Furthermore, in the case of barley and rye, the endosperm cell walls also contained high amounts of β-glucan. Interestingly, β-glucan in rye and barley endosperm cell walls was located adjacent to the cell contents, suggesting that it is not evenly distributed in the endosperm cell walls. The results give new insight into the structure of the cereal dietary fiber complex. Further development of microscopic techniques will help in elucidating the cereal cell wall structure even in more detail.     

Seven distinct dietary patterns identified among pregnant Finnish women--associations with nutrient intake and sociodemographic factors

OBJECTIVES: To identify and describe dietary patterns in a cohort of pregnant women and investigate whether the dietary patterns are associated with dietary intake and sociodemographic factors. DESIGN: Mothers entering the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Nutrition Study in 1997-2002 were retrospectively asked to complete a food-frequency questionnaire concerning their diet during pregnancy. Principal components analysis was used to identify dietary patterns. SETTING: Finland. SUBJECTS: Subjects were 3730 women with a newborn infant carrying increased genetic susceptibility to type 1 diabetes mellitus. RESULTS: Seven factors were identified and named. Energy intake correlated positively with 'Healthy', 'Fast food', 'Traditional bread', 'Traditional meat' and 'Coffee' patterns and inversely with the 'Alcohol and butter' pattern. Intake of dietary fibre correlated positively with 'Healthy', 'Traditional bread' and 'Low-fat foods' patterns and inversely with the 'Alcohol and butter' pattern. The seven dietary patterns seemed to account for relatively large proportions of the variance in energy and nutrient intakes except for the intake of vitamin D, vitamin C, carotenoids and calcium. Maternal age and higher level of education were associated with higher scores on 'Healthy', 'Low-fat foods' and 'Alcohol and butter' patterns. CONCLUSION: Principal components analysis produced seven dietary patterns which may be useful for further research concerning maternal diet and health outcomes among both mothers and their offspring.     

Effect of soil water tension and harvest time on levels of infestation byPhoma foveata Foister in soil and on tubers and stems of potato (Solanum tuberosum L.) in northern Sweden

Summary The incidence ofP. foveata in soil and tuber samples from field experiments often increased significantly as the harvest season progressed and temperatures fell. Mean levels of tuber and soil infestation were significantly higher in irrigated rows compared with those artificially sheltered from precipitation, both at normal and late harvest dates. Soil infestation was most frequently detected within 10 cm of the parent tuber. No pycnidia were visible on the haulm, and very few latently infected stem segments and leaves were detected using various methods. In three out of four years, the incidence ofP. foveata in tubers after wounding was reduced by washing them gently in tap water immediately after harvest.     

Co-incubation with IL-18 potentiates antigen-specific IFN-γ response in a whole-blood stimulation assay for measurement of cell-mediated immune responses in pigs experimentally infected with Lawsonia intracellularis

The whole-blood interferon-gamma (IFN-γ) assay is a quantitative in vitro assay for a direct read-out of Ag-specific cell-mediated immune (CMI) responses to infectious diseases. The IFN-γ assay is robust in severe intracellular infections like Brucella or mycobacteria, but more difficult to evaluate for less severe or immunocompromising infections. Here we investigated the performance of the assay when recombinant co-stimulatory cytokines IL-12 and/or IL-18 were added along with Ag or PBS to cultures of whole-blood from pigs infected with Lawsonia intracellularis. In pigs recovering from a natural infection, addition of rIL-12 or rIL-18 alone increased the Ag-specific IFN-γ release while addition of both cytokines resulted in increased IFN-γ release also in PBS cultures. In analyses after experimental infections with L. intracellularis, significant increased levels of Ag-specific IFN-γ production were measured in Ag+rIL-18 cultures from infected pigs compared to the background response in PBS+rIL-18 control samples (p<0.01) or to Ag+rIL-18 cultures from non-inoculated control pigs (p<0.05). Flow cytometry identified two lymphocyte subsets as the Ag-specific IFN-γ producers. The highest IFN-γ production was by CD4(+)CD8(+) cells while a more numerous population of CD4(-)CD8(+) cells produced lower amounts of IFN-γ in response to rIL-18 and L. intracellularis Ag.     

Primary infection protects pigs against re-infection with Lawsonia intracellularis in experimental challenge studies

In two separate trials pigs were experimentally infected with Lawsonia intracellularis at 5-6 weeks of age followed by antibiotic treatment and resolution of the primary infection and then re-inoculated at 12-13 weeks of age. A treatment-control group of pigs received the primary infection and antibiotic treatment only, and served as control for the antibiotic treatment of the primary infection. A challenge-control group of pigs received the second inoculation dose only at 12-13 weeks of age to control infectivity of the challenge-dose and susceptibility of pigs to L. intracellularis at this age. Pigs were monitored for shedding of L. intracellularis in faeces by PCR, and for the development of antibodies and responses of acute phase proteins in serum. The presence of L. intracellularis antigen in the intestinal mucosa was examined in post mortem samples by immunohistochemistry. In both trials primary infected pigs were protected from infection after challenge inoculation as evidenced by absence of faecal shedding of L. intracellularis, lack of changes in acute phase protein concentrations after challenge and with low levels of bacterial antigen in the intestinal mucosa of re-inoculated pigs comparable to that of the treatment-control pigs. In contrast, challenge-control pigs shed L. intracellularis in faeces, had L. intracellularis antigen extensively present within all layers of the intestinal mucosa and developed a significant acute phase protein response in serum after the experimental infection. The acute phase protein response to L. intracellularis infection was detected as an increased rise in the serum concentrations of C-reactive protein and haptoglobin from day-6 post infection, and increased serum concentrations of haptoglobin were generally seen 2-3 weeks after inoculation both at 5-6 and 12-13 weeks of age. In conclusion substantial protection against L. intracellularis infection was found in the re-inoculated pigs in contrast to the development of infection in age-matched control pigs. The acute phase protein responses reflected both the observed protection against L. intracellularis infection upon secondary challenge and that increased resistance to the infection develops with age.     

A common variant in the FTO gene is associated with body mass index and predisposes to childhood and adult obesity

Obesity is a serious international health problem that increases the risk of several common diseases. The genetic factors predisposing to obesity are poorly understood. A genome-wide search for type 2 diabetes-susceptibility genes identified a common variant in the FTO (fat mass and obesity associated) gene that predisposes to diabetes through an effect on body mass index (BMI). An additive association of the variant with BMI was replicated in 13 cohorts with 38,759 participants. The 16% of adults who are homozygous for the risk allele weighed about 3 kilograms more and had 1.67-fold increased odds of obesity when compared with those not inheriting a risk allele. This association was observed from age 7 years upward and reflects a specific increase in fat mass.