The Photoreceptor Outer Segments of the River Lamprey (Lampreta fluviatilis). An Electron-, Fluorescence- and Light Microscopic Study

The outer segment of long and short photoreceptors in the retina of the river lamprey, Lampetra fluviatilis, were studied by light- and fluorescence microscopy together with some different electron microscopic methods. The outer segments show characteristics of both rods and cones and are suggested to represent intermediate kinds of photoreceptors.     

Glutamine is not an essential amino acid for Sf-9 insect cells

Summary Spodoptera frugiperda (Sf-9) insect cells are fully capable of growth and proliferation in a glutamine, glutamate and aspartate-free medium, provided that ammonium ions are supplied. S. frugiperda (Sf-21) and Mamestra brassicae cells (IZD-MB-0503) also grow in glutamine-free media but not Trichoplusia ni cells (BTI-TN 5B1-4). The yield of -galactosidase in Sf-9 cells infected with a recombinant baculovirus under glutamine-free conditions was even higher than the yield obtained in glutamine containing cultures.     

Host relationships ofDasineura ingeris: oviposition preferences and juvenile survival on clones ofSalix viminalis, otherSalix species and hybrids

In the present study we assessed the extent to which oviposition preferences and larval survival rates of the gall midge Dasineura ingeris Sylvén & Lövgren (Diptera: Cecidomyiidae) can explain variation in its use of Salix viminalis phenotypes as hosts. Furthermore, based on oviposition preferences and juvenile survival rates we estimated the host potential of various Salix species and species hybrids. Egg distribution patterns explained 67% of the intraspecific variation in damage to S. viminalis shoots in the field. Juvenile survival, on the other hand, was not related to field damage or egg distribution patterns among the S. viminalis clones studied. Clones of complete or partial S. viminalis origin ranked highest in suitability for D. ingeris survival, and four out of these six clones also received the highest egg rankings. Species belonging to the subgenus Salix were not oviposited on at all, whereas others belonging to the same subgenus as S. viminalis, i.e. Vetrix, were intermediate in terms of oviposition rates. Although there was a significant correlation between D. ingeris egg distributions and larval survival rates on the clones in the Salix species/hybrid set, mismatches were evident.     

Radiocaesium in lynx in relation to ground deposition and diet

The european lynx (Lynx lynx) might be expected to have a high intake of radiocaesium in the parts of Sweden where the main prey of the lynx, namely reindeer and roe deer have high activity concentrations of radiocaesium because of high ground deposition. We have measured ¹³⁷Cs in muscle samples from 733 lynx during 1996–2003. The aim was to quantify the extent to which radiocaesium is transferred from fallout deposition to lynx, to test whether the transfer was higher in areas where there are reindeer present, to see if there was any decline in radiocaesium over time, and to calculate the radiation dose to lynx. Most samples were collected in central and northern Sweden during January–April. Activity concentrations in lynx varied from 13 Bq kg^–1 to about 15 kBq kg^–1 fresh weight, with the highest value corresponding to a radiation dose at 18 mGy/year. Aggregated transfer coefficients (Tag), calculated by dividing the ¹³⁷Cs activity concentration in lynx muscle by the average ground deposition (total from Chernobyl and nuclear weapon tests) within a 50 km radius around the location of the lynx, varied from 0.004 to 1.3 m² kg^–1 and were significantly higher within the reindeer herding area than outside. The concentration ratio (CR) for lynx/reindeer was 2.6 on average, whilst the average for lynx/roe deer outside the reindeer herding area was lower at 1.3. Based on these results, a CR of around 2 could be considered representative for the general ratio between predator and prey. A long-term decline of radiocaesium in prey species was reflected in lynx, with an effective half-life of 7 years from 1996 to 2003. The study shows that the accumulation of radiocaesium in predators, especially predators of reindeer, makes them more vulnerable to high radiocaesium deposition than most other wild species.     

Pea Lectin Expressed Transgenically in Oilseed Rape Reduces Growth Rate of Pollen Beetle Larvae

In several studies plant lectins have shown promise as transgenic resistance factors against various insect pests. We have here shown that pea seed lectin is a potential candidate for use against pollen beetle, a serious pest of Brassica oilseeds. In feeding assays where pollen beetle larvae were fed oilseed rape anthers soaked in a 1% solution of pea lectin there was a reduction in survival of 84% compared to larvae on control treatment and the weight of surviving larvae was reduced by 79%. When a 10% solution of pea lectin was used all larvae were dead after 4 days of testing. To further evaluate the potential use of pea lectin, transgenic plants of oilseed rape (Brassica napus cv. Westar) were produced in which the pea lectin gene under control of the pollen-specific promoter Sta44-4 was introduced. In 11 out of 20 tested plants of the T₀-generation there was a significant reduction in larval weight, which ranged up to 46% compared to the control. A small but significant reduction in larval survival rate was also observed. In the T₂-generation significant weight reductions, with a maximum of 32%, were obtained in 10 out of 33 comparisons between transgenic plants and their controls. Pea lectin concentrations in anthers of transgenic T₂-plants ranged up to 1.5% of total soluble protein. There was a negative correlation between lectin concentration and larval growth. Plants from test groups with significant differences in larval weights had a significantly higher mean pea lectin concentration, 0.64% compared to 0.15% for plants from test groups without effect on larval weight. These results support the conclusion that pea lectin is a promising resistance factor for use in Brassica oilseeds against pollen beetles.     

Maturation of Oral Microbiota in Children with or without Dental Caries

Background

The aim of this longitudinal study was to evaluate the oral microbiota in children from age 3 months to 3 years, and to determine the association of the presence of caries at 3 years of age.

Methods and findings

Oral biofilms and saliva were sampled from children at 3 months (n = 207) and 3 years (n = 155) of age, and dental caries was scored at 3 years of age. Oral microbiota was assessed by culturing of total lactobacilli and mutans streptococci, PCR detection of Streptococcus mutans and Streptococcus sobrinus, 454 pyrosequencing and HOMIM (Human Oral Microbe Identification Microarray) microarray detection of more then 300 species/ phylotypes. Species richness and taxa diversity significantly increased from 3 months to 3 years. Three bacterial genera, present in all the 3-month-old infants, persisted at 3 years of age, whereas three other genera had disappeared by this age. A large number of new taxa were also observed in the 3-year-olds. The microbiota at 3 months of age, except for lactobacilli, was unrelated to caries development at a later age. In contrast, several taxa in the oral biofilms of the 3-year-olds were linked with the presence or absence of caries. The main species/phylotypes associated with caries in 3-year-olds belonged to the Actinobaculum, Atopobium, Aggregatibacter, and Streptococcus genera, whereas those influencing the absence of caries belonged to the Actinomyces, Bergeyella, Campylobacter, Granulicatella, Kingella, Leptotrichia, and Streptococcus genera.

Conclusions

Thus, during the first years of life, species richness and taxa diversity in the mouth increase significantly. Besides the more prevalent colonization of lactobacilli, the composition of the overall microbiota at 3 months of age was unrelated to caries development at a later age. Several taxa within the oral biofilms of the 3-year-olds could be linked to the presence or absence of caries.     

Plant volatile-induced aphid resistance in barley cultivars is related to cultivar age

Recent studies have shown that volatile chemical interaction between certain barley (Hordeum vulgare) cultivars can cause reduced host plant acceptance by the aphid Rhopalosiphum padi, and that certain cultivars can induce this effect while others can respond. In this study, we tested whether inducing and responding capabilities are linked to year of release in Swedish two-rowed spring barley. Eighteen cultivars released between 1897 and 1992 were tested in randomly selected subsets with pairwise combinations of volatile emitters and receivers. Significantly reduced aphid acceptance as a result of exposure to volatiles from plants of a different cultivar were found in 24% of the cultivar combinations. In general, older cultivars had a higher degree of aphid resistance after barley volatile treatment than did younger cultivars. The inducing effect of the emitter was also related to date of emitter cultivar release but the time relationship was reversed. Combinations with a younger volatile emitter and an older volatile receiver gave the strongest reduction in aphid acceptance of treated plants. Linear relationships between microsatellite diversity of emitting cultivars and their efficiency as inducers indicated that younger cultivars might have a more unique odour, whereas older cultivars may be more sensitive to induction.     

Quantitative Changes in Gimap3 and Gimap5 Expression Modify Mitochondrial DNA Segregation in Mice

Mammalian mitochondrial DNA (mtDNA) is a high-copy maternally inherited genome essential for aerobic energy metabolism. Mutations in mtDNA can lead to heteroplasmy, the co-occurence of two different mtDNA variants in the same cell, which can segregate in a tissue-specific manner affecting the onset and severity of mitochondrial dysfunction. To investigate mechanisms regulating mtDNA segregation we use a heteroplasmic mouse model with two polymorphic neutral mtDNA haplotypes (NZB and BALB) that displays tissue-specific and age-dependent selection for mtDNA haplotypes. In the hematopoietic compartment there is selection for the BALB mtDNA haplotype, a phenotype that can be modified by allelic variants of Gimap3. Gimap3 is a tail-anchored member of the GTPase of the immunity-associated protein (Gimap) family of protein scaffolds important for leukocyte development and survival. Here we show how the expression of two murine Gimap3 alleles from Mus musculus domesticus and M. m. castaneus differentially affect mtDNA segregation. The castaneus allele has incorporated a uORF (upstream open reading frame) in-frame with the Gimap3 mRNA that impairs translation and imparts a negative effect on the steady-state protein abundance. We found that quantitative changes in the expression of Gimap3 and the paralogue Gimap5, which encodes a lysosomal protein, affect mtDNA segregation in the mouse hematopoietic tissues. We also show that Gimap3 localizes to the endoplasmic reticulum and not mitochondria as previously reported. Collectively these data show that the abundance of protein scaffolds on the endoplasmic reticulum and lysosomes are important to the segregation of the mitochondrial genome in the mouse hematopoietic compartment.     

Cardiovascular events in early RA are a result of inflammatory burden and traditional risk factors: a five year prospective study

Introduction  

Co-morbidity and mortality due to cardiovascular disease (CVD) are increased in patients with rheumatoid arthritis (RA). Most published studies in this field are retrospective or cross sectional. We investigated the presence of traditional and disease related risk factors for CVD at the onset of RA and during the first five years following diagnosis. We also evaluated their potential for predicting a new cardiovascular event (CVE) during the five-year follow-up period and the modulatory effect of pharmacological treatment.