The plasma membrane of Streptococcus cremoris: isolation and partial characterization

Plasma membrane was isolated from Streptococcus cremoris using mutanolysin from a streptomycete as the cell wall-degrading enzyme and phenylmethylsulfonyl fluoride as protease inhibitor. The specific activity of membrane-bound enzyme, adenosine triphosphatase (ATPase), was 4 μmol/mg protein per min, which was 5–10 times higher than the activity found in other fractions obtained during the isolation procedure. The number of polypeptides in the plasma membrane was approximately 50 with molecular weights 13 500–100 000, minor changes in the polypeptide pattern were observed when the plasma membrane was isolated without a protease inhibitor. The chemical composition of the membrane preparation was 49.7% protein, 21.9% lipid, 5.1% aminosugars, 17.3% RNA and 0.03% DNA. Electron microscopic examination confirmed the membrane to be practically devoid of cell wall components. Our results indicate that the membrane integrity is well retained and therefore the membrane preparation is suitable for detailed studies on vectorial metabolism and its enzymes, e.g. ATPase.     

Early Life Stress and Physical and Psychosocial Functioning in Late Adulthood

Background

Severe stress experienced in early life may have long-term effects on adult physiological and psychological health and well-being. We studied physical and psychosocial functioning in late adulthood in subjects separated temporarily from their parents in childhood during World War II.

Methods

The 1803 participants belong to the Helsinki Birth Cohort Study, born 1934–44. Of them, 267 (14.8%) had been evacuated abroad in childhood during WWII and the remaining subjects served as controls. Physical and psychosocial functioning was assessed with the Short Form 36 scale (SF-36) between 2001 and 2004. A test for trends was based on linear regression. All analyses were adjusted for age at clinical examination, social class in childhood and adulthood, smoking, alcohol intake, physical activity, body mass index, cardiovascular disease and diabetes.

Results

Physical functioning in late adulthood was lower among the separated men compared to non-separated men (b = −0.40, 95% confidence interval [95% CI]: −0.71 to −0.08). Those men separated in school age (>7 years) and who were separated for a duration over 2 years had the highest risk for lower physical functioning (b = −0.89, 95% CI: −1.58 to −0.20) and (b = −0.65, 95% CI: −1.25 to −0.05), respectively). Men separated for a duration over 2 years also had lower psychosocial functioning (b = −0.70, 95% CI: −1.35 to −0.06). These differences in physical and psychosocial functioning were not observed among women.

Conclusion

Early life stress may increase the risk for impaired physical functioning in late adulthood among men. Timing and duration of the separation influenced the physical and psychosocial functioning in late adulthood.     

Immune response is energetically costly in white cabbage butterfly pupae

Parasite-driven coevolution has led hosts to develop a complicated and potentially costly defence machinery, consisting mainly of the immune system. Despite the evidence for the trade-offs between immune function and life-history traits, it is still obscure how the costs of using and maintaining the immune function are paid. We tested whether immune challenge is energetically costly for white cabbage butterfly (Pieris brassicae L.) diapausing pupa. Individuals challenged with nylon implant raised their standard metabolic rate nearly 8% compared to the controls. Hence, costs of activation of immune system in insect pupa can be expressed in energetic currency.     

Transforming growth factor-beta stimulates parathyroid hormone-related protein and osteolytic metastases via Smad and mitogen-activated protein kinase signaling pathways

Transforming growth factor (TGF)-beta promotes breast cancer metastasis to bone. To determine whether the osteolytic factor parathyroid hormone-related protein (PTHrP) is the primary mediator of the tumor response to TGF-beta, mice were inoculated with MDA-MB-231 breast cancer cells expressing a constitutively active TGF-beta type I receptor. Treatment of the mice with a PTHrP-neutralizing antibody greatly decreased osteolytic bone metastases. There were fewer osteoclasts and significantly decreased tumor area in the antibody-treated mice. TGF-beta can signal through both Smad and mitogen-activated protein (MAP) kinase pathways. Stable transfection of wild-type Smad2, Smad3, or Smad4 increased TGF-beta-stimulated PTHrP secretion, whereas dominant-negative Smad2, Smad3, or Smad4 only partially reduced TGF-beta-stimulated PTHrP secretion. When the cells were treated with a variety of protein kinases inhibitors, only specific inhibitors of the p38 MAP kinase pathway significantly reduced both basal and TGF-beta-stimulated PTHrP production. The combination of Smad dominant-negative blockade and p38 MAP kinase inhibition resulted in complete inhibition of TGF-beta-stimulated PTHrP production. Furthermore, TGF-beta treatment of MDA-MB-231 cells resulted in a rapid phosphorylation of p38 MAP kinase. Thus, the p38 MAP kinase pathway appears to be a major component of Smad-independent signaling by TGF-beta and may provide a new molecular target for anti-osteolytic therapy.     

Genetic polymorphism of the human ICOS gene

Inducible costimulator (ICOS) is a novel receptor belonging to the same family as CD28 and CTLA4, which regulate T-lymphocyte activation in the immune response. The genes for these molecules are located adjacent to each other on Chromosome 2q33. Many autoimmune diseases have been found to be genetically linked to or associated with genetic markers near the CTLA4 gene. However, as all three genes are closely linked and have related functions, it is possible that the findings could be explained by variation in CD28 or ICOS. Few data on genetic variation in the ICOS gene are available. We sequenced the ICOS gene in 13 healthy unrelated individuals and found eight single nucleotide polymorphisms. One was located in the first intron, and the others in the untranslated region of the last exon. The allele frequencies and linkage disequilibrium were determined from a population sample of 63 Finnish individuals. The results show that the ICOS gene is polymorphic, but no variation in the coding sequence was detected, implying that the genetic linkage of this gene region to autoimmune diseases may not result from structural variation in the ICOS molecule. These polymorphisms, however, should be useful in genetic studies of this candidate gene.     

Selective binding of synapse-associated protein 97 to GluR-A alpha-amino-5-hydroxy-3-methyl-4-isoxazole propionate receptor subunit is determined by a novel sequence motif

A family of four closely related PDZ domain-containing membrane-associated guanylate kinase homologues (MAGUKs) is involved in the regulation of the amount and functional state of ionotropic glutamate receptors in excitatory synapses. To understand the mechanisms that determine the specificity of these interactions, we examined the structural basis of the highly selective association between the ionotropic GluR subunit GluR-A and synapse-associated protein 97 (SAP97). The C terminus of GluR-A bound to the PDZ domains of SAP97, but not to those of three related MAGUKs, PSD-93, PSD-95, and SAP102. Experiments with single PDZ domains indicated that the strongest contribution was by the second PDZ domain. Unexpectedly, mutation analysis of the GluR-A C terminus revealed that a tripeptide sequence SSG at position -9 to -11 plays an essential role in this binding, in addition to a C-terminal type I PDZ binding motif (leucine at C terminus and threonine at the -2 position). Analysis of the in vitro MAGUK-binding properties of a GluR-D mutant with a one-residue deletion at the C terminus provides further support for the view that an SSG sequence located N-terminally from a type I PDZ binding motif can mediate selective binding to SAP97 and suggest the existence of a novel variation of the PDZ domain-peptide interaction.     

Infant Growth after Preterm Birth and Mental Health in Young Adulthood

Objectives

Faster growth after preterm birth benefits long-term cognitive functioning. Whether these benefits extend to mental health remains largely unknown. We examined if faster growth in infancy is associated with better self-reported mental health in young adults born preterm at very low birth weight (VLBW) (<1500g).

Study Design

As young adults, participants of the Helsinki Study of Very Low Birth Weight Adults self-reported symptoms of depression and attention deficit/hyperactivity disorder (ADHD) (n = 157) and other psychiatric problems (n = 104). As main predictors of mental health outcomes in linear regression models, we used infant weight, length, and head circumference at birth, term, and 12 months of corrected age, and growth between these time points. Growth data were collected from records and measures at term and at 12 months of corrected age were interpolated. Additionally, we examined the moderating effects of intrauterine growth restriction.

Results

Size at birth, term, or 12 months of corrected age, or growth between these time points were not associated with mental health outcomes (p-values >0.05). Intrauterine growth restriction did not systematically moderate any associations.

Conclusions

Despite the high variability in early growth of VLBW infants, the previously described association between slow growth in infancy and poorer cognitive functioning in later life is not reflected in symptoms of depression, ADHD, and other psychiatric problems. This suggests that the development of cognitive and psychiatric problems may have dissimilar critical periods in VLBW infants.     

Gene, phenotype and function: GLABROUS1 and resistance to herbivory in natural populations of Arabidopsis lyrata

The molecular genetic basis of adaptive variation is of fundamental importance for evolutionary dynamics, but is still poorly known. Only in very few cases has the relationship between genetic variation at the molecular level, phenotype and function been established in natural populations. We examined the functional significance and genetic basis of a polymorphism in production of leaf hairs, trichomes, in the perennial herb Arabidopsis lyrata. Earlier studies suggested that trichome production is subject to divergent selection. Here we show that the production of trichomes is correlated with reduced damage from insect herbivores in natural populations, and using statistical methods developed for medical genetics we document an association between loss of trichome production and mutations in the regulatory gene GLABROUS1. Sequence data suggest that independent mutations in this regulatory gene have provided the basis for parallel evolution of reduced resistance to insect herbivores in different populations of A. lyrata and in the closely related Arabidopsis thaliana. The results show that candidate genes identified in model organisms provide a valuable starting point for analysis of the genetic basis of phenotypic variation in natural populations.     

Population screening for coeliac disease in primary care by district nurses using a rapid antibody test: diagnostic accuracy and feasibility study

Objective To evaluate the feasibility and diagnostic accuracy of screening for coeliac disease by rapid detection of IgA antibodies to tissue transglutaminase performed in primary care.Design District nurses screened 6 year old children using rapid antibody testing of finger prick blood. They also collected capillary blood samples for laboratory determination of IgA and IgG antibodies to endomysium and IgA antibodies to tissue transglutaminase. Children with positive rapid test results were directly sent for biopsy of the small intestine.Setting Primary care in Jász-Nagykun-Szolnok county, Hungary.Participants 2690 children (77% of 6 year olds living in the county) and 120 nurses.Main outcome measures Positivity for antibodies to endomysium or transglutaminase in the laboratory and coeliac disease confirmed at biopsy.Results 37 children (1.4%, 95% confidence interval 0.9% to 1.8%) had biopsy confirmed coeliac disease. Only five of these children had been diagnosed clinically before screening. Rapid testing had a 78.1% sensitivity (70.0% to 89.3%) and 100% specificity (88.4% to 100%) for a final diagnosis of coeliac disease by biopsy. Sensitivity was 65.1% (50.2% to 77.6%) and specificity was 100% (99.8% to 100%) compared with combined results of IgA and IgG laboratory tests. Trained laboratory workers detected 30 of the 31 newly diagnosed IgA competent patients with the rapid test kit used blindly. Median time to biopsy after a positive rapid test result was significantly shorter (20 days, range 4-148) than after a positive laboratory result (142 days, 70-256; P<0.001). Children with coeliac disease detected at screening were smaller and had worse health status than their peers but they improved on a gluten-free diet.Conclusions A simple rapid antibody test enabled primary care nurses to detect patients with coeliac disease in the community who were not picked up in clinical care. Extra training is needed to improve sensitivity.