Role of different lymphoid tissues in the initiation and maintenance of DNA-raised antibody responses to the influenza virus H1 glycoprotein.

Antibody responses in mice immunized by a single gene gun inoculation of plasmid expressing the influenza virus H1 hemagglutinin and in mice immunized by a sublethal H1 influenza virus infection have been compared. Both immunizations raised long-lived serum responses that were associated with the localization of antibody-secreting cells (ASC) to the bone marrow. However, the kinetics of these responses were 4 to 8 weeks slower in the DNA-immunized than in the infection-primed mice. Following a gene gun booster, the presence of ASC in the inguinal lymph nodes, but not in other lymph nodes, revealed gene gun responses being initiated in the nodes that drain the skin target site. Both pre- and postchallenge, the DNA-immunized mice had 5- to 10-times-lower levels of antibody and ASC than the infection-primed mice.     

Single mothers in Ontario: sociodemographic,physical and mental health characteristics

OBJECTIVE: To examine the sociodemographic, physical and mental health characteristics of single mothers in Ontario. DESIGN: Cross-sectional. SETTING: Ontario. PARTICIPANTS: Ontario residents aged 15 years or older who participated in the Ontario Health Supplement survey conducted between December 1990 and April 1991; of 9953 eligible participants, 1540 were mothers with at least 1 dependent child (less than 16 years of age). OUTCOME MEASURES: Prevalence rates of sociodemographic, physical and mental health characteristics. RESULTS: Single mothers were significantly more likely than the mothers in 2-parent families to be poor, to be 25 years of age or less, to have mental health problems (dissatisfaction with multiple aspects of life, affective disorder ever and 1 or more psychiatric disorders in the past year or ever) and to use mental health services. When compared by income level, poor single mothers had a higher prevalence of all mental health outcomes measured; the difference was significant for anxiety disorder in the past year or ever and for 1 or more psychiatric disorders in the past year or ever. In a logistic regression analysis, single-mother status was found to have the strongest independent effect on predicting mental health morbidity and utilization of mental health services; the next strongest was low income. CONCLUSIONS: Single mothers are more likely to be poor, to have an affective disorder and to use mental health services than mothers in 2-parent families. The risk of mental health problems is especially pronounced among poor single mothers. Further studies are needed to determine which aspects of single motherhood, apart from economic status, affect mental health outcomes.     

Adenosine/Adenine-Containing Nucleotides in the Leaves and Roots of Young Barley Plants after Infection of the Primary Leaf by Erysiphe graminis

The levels of adenosine, the adenine nucleotides AMP, ADP, ATP, as well as NAD, NADP, protein and chlorophyll were determined in young barley plants of which the primary leaves were infected by Erysiphe graminis DC. f. sp. hordei MARCHAL. The largest changes of these metabolite levels, compared to the non-infected control, occurred in the infected leaf and to a lesser degree also in the roots and in healthy younger leaves. The increase in the levels of most metabolites in the primary leaf revealed the sink property of this infected tissue and possible stress or defence reactions of the host, whereas the reductions in the roots showed the impaired supply of this natural sink organ due to the infection. Changes in the healthy leaves were most pronounced in the tertiary leaf and may reflect metabolic stimulation in that healthy organ. The changes of the adenosine pool, a precursor of the adenine nucleotides, were discussed in terms of translocation and its possible role as a precursor for fungal purine nucleotide synthesis.     

Elemental Fingerprinting of Mussel Shells to Predict Population Sources and Redistribution Potential in the Gulf of Maine

As the climate warms, species that cannot tolerate changing conditions will only persist if they undergo range shifts. Redistribution ability may be particularly variable for benthic marine species that disperse as pelagic larvae in ocean currents. The blue mussel, Mytilus edulis, has recently experienced a warming-related range contraction in the southeastern USA and may face limitations to northward range shifts within the Gulf of Maine where dominant coastal currents flow southward. Thus, blue mussels might be especially vulnerable to warming, and understanding dispersal patterns is crucial given the species'' relatively long planktonic larval period (>1 month). To determine whether trace elemental “fingerprints” incorporated in mussel shells could be used to identify population sources (i.e. collection locations), we assessed the geographic variation in shell chemistry of blue mussels collected from seven populations between Cape Cod, Massachusetts and northern Maine. Across this ∼500 km of coastline, we were able to successfully predict population sources for over two-thirds of juvenile individuals, with almost 80% of juveniles classified within one site of their collection location and 97% correctly classified to region. These results indicate that significant differences in elemental signatures of mussel shells exist between open-coast sites separated by ∼50 km throughout the Gulf of Maine. Our findings suggest that elemental “fingerprinting” is a promising approach for predicting redistribution potential of the blue mussel, an ecologically and economically important species in the region.     

Characterization of Competitive Inhibitors for the Transferase Activity of Pseudomonas aeruginosa Exotoxin A

A series of small, nonpolar compounds were tested for their ability to inhibit the ADP-ribosyl transferase activity of Pseudomonas aeruginosa exotoxin A. The IC 50 values for the compounds tested ranged from 87 nM to 484 μM for NAP and CMP12, respectively. It was demonstrated that NAP was a competitive inhibitor of the ADPRT reaction for the NAD + substrate with a K i of 45 ± 5 nM, which was in good agreement with the dissociation constant determined independently (K D =56 ± 6 nM). The IC 50 value for NAP was 87 ± 12 nM, which strongly correlated with the K i and K D values. Furthermore, NAP was shown to noncovalently associate with the exotoxin A active site using exhaustive dialysis, NMR, and electrospray mass spectrometry. Finally, a computer molecular model using the X-ray structure of the substrate-bound toxin was generated with NAP bound to the active site of exotoxin A at the nicotinamide-binding site. This model is consistent with the X-ray structure of the catalytic domain of poly-ADP-ribose polymerase complexed with 4-amino-naphthalimide (Compound 4) that was included in this study.     

Effects of exogenous fatty acids on calcium uptake by brush-border membrane vesicles from rabbit small intestine

The uptake of a variety of fatty acids by isolated brush-border membranes from rabbit small intestine was studied. This uptake increased with acyl chain-length and was not diminished by washing of the lipid-treated membranes with 0.25 M CsBr. The binding of fatty acid was not accompanied by a decrease in endogenous acyl groups or of cholesterol and therefore corresponded to a net uptake accountable qualitatively and quantitatively by the fatty acid added to the membranes. The uptake of Ca2+ was stimulated by treatment of the membranes with low concentrations of unsaturated fatty acids (0.05 mM) as well as with various concentrations of caprylic acid (0.10-3.00 mM) and inhibited by treatment with higher concentrations of unsaturated fatty acids (0.20-0.60 mM). Saturated fatty acids had no marked effects on Ca2+ uptake. The stimulatory concentrations of unsaturated fatty acids did not change the Ca2+-binding characteristics of the membranes, whereas the higher concentrations decreased equilibrium binding of Ca2+ and very probably the number of high-affinity binding sites. The results of this study are assessed in terms of the effects of normal fatty acids found in the diet on the absorptive properties of the brush-border membranes.     

Apparent survival of tropical birds in a wet,premontane forest in Costa Rica

Despite the importance of tropical birds in the development of life history theory, we lack information about demographic rates and drivers of population dynamics for most species. We used a 7‐year (2007–2013) capture‐mark‐recapture dataset from an exceptionally wet premontane forest at mid‐elevation in Costa Rica to estimate apparent survival for seven species of tropical passerines. For four of these species, we provide the first published demographic parameters. Recapture probabilities ranged from 0.21 to 0.53, and annual estimates of apparent survival varied from 0.23 to 1.00. We also assessed the consequences of inter‐annual variation in rainfall on demographic rates. Our results are consistent with inter‐annual rainfall increasing estimates of apparent survival for two species and decreasing estimates for three species. For the three species where we could compare our estimates of apparent survival to estimates from drier regions, our estimates were not consistently higher or lower than those published previously. The temporal and spatial variability in demographic rates we document within and among species highlights the difficulties of generalizing life history characteristics across broad biogeographic gradients. Most importantly, this work emphasizes the context‐specific role of precipitation in shaping tropical avian demographic rates and underscores the need for mechanistic studies of environmental drivers of tropical life histories.