A group A streptococcal Enn protein potentially resulting from intergenomic recombination exhibits atypical immunoglobulin-binding characteristics

The gene encoding the Enn protein (enn) of the M untypeable group A streptococcal (GAS) strain 64/14 was amplified by polymerase chain reaction, cloned into the expression vector pJLA602 and expressed in Escherichia coli DH5α. Unlike other GAS–Enn proteins, which exhibit IgA-binding activity, the recombinant Enn enn64/14 protein reacted preferentially with human IgG₃. The 1050 bp open reading frame comprising the enn64/14 gene was completely sequenced. The region of the gene encoding the signal peptide and the C-terminus exhibited >95% homology to corresponding sections of other enn genes. The region of enn64/74 encoding the N-terminus of the mature Enn protein was found to be highly homologous to the corresponding section of the gene encoding the M-like protein of GAS serotype M9 (emmL9). The reoombinant protein encoded by emmL9 was found to react with all four human IgG subclasses. About 30% of the 1152bp open reading frame of emmiL9 encoding the N-terminus was found to display >90% homology to the corresponding section of enn64/14 but was <50% homologous in the remainder of the gene sequence. The functional analysis of the subcloned N-terminal section of emmL9 demonstrated a polypeptide exhibiting selective binding to human IgG₃. These findings suggested that enn64/14 was a hybrid gene formed by recombination of an enn gene and an emmL9 gene. The putative recombinational event could have Involved a set of flanking 7bp direct repeats. Since enn64/14 and emmL9 are genes from different phylogenetic lineages of GAS, this report provides evidence that intergenomic recombinations between different types of GAS genes can occur and could lead to hybrid proteins with unique Ig-binding characteristics.     

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.     

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.     

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.     

The molecular basis of potassium nutrition in plants

Over the last five years, the cloning and characterization of K⁺ transport genes corresponding to K⁺ channels (KAT1, AKT1, KST1, AKT2), associated subunits (KAB1) and a high-affinity transporter (HKT1) has opened up important new avenues for research on plant K⁺ nutrition. With the abundance of molecular data now available it seems timely to link this information with the wealth of data previously accumulated on the physiology of plant K⁺ acquisition. The ultimate goal of all this research is to gain a better understanding of K⁺ transport and nutrition in the intact plant. Thus it is important to begin to integrate the molecular research with results from biochemical and physiological research conducted at the cellular, root and whole plant levels. This article will focus on describing the features of the cloned K⁺ transporters and their possible roles in mediating high- and low-affinity K⁺ uptake from the soil, as well as how K⁺ acquisition may be regulated.Abbreviations NEM N-ethyl maleimide - PCMBS p-chloromercuribenzene sulphonic acid     

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.     

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.     

Biochemical studies of taste sensation. XI. Isolation, characterization and taste ligand binding activity of plasma membranes from catfish taste tissue

Variants of creatine kinase-MM (variant of ATP:creatine N-phosphotransferase, EC 2.7.3.2), present in human heart and skeletal muscle, have been purified to homogeneity using DEAE-Sepharose column chromatography and column chromatofocusing techniques. Creatine kinase-MM I-IV were present in both heart and skeletal muscle, while MM-V was found only in heart. The number, ratio and elution profile of the variants during chromatofocusing remained identical even when they were purified in the presence of proteinase inhibitors. MM-I-V, on chromatofocusing, were eluted at pH 8.3, 7.9, 7.6, 7.2 and 6.8, respectively. Isoelectric focusing revealed the pI of MM-I-V to be 7.2, 6.9, 6.7, 6.4 and 6.2. Sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis showed a doublet pattern for creatine kinase-MM variants III-V. However, polyacrylamide gel electrophoresis without SDS indicated homogeneity because each variant showed a single band. The doublet pattern observed in the presence of SDS may reflect the presence of two subunits of slightly different mass.     

Hazard Ranking Methodology for Assessing Health Impacts of Unconventional Natural Gas Development and Production: The Maryland Case Study

The recent growth of unconventional natural gas development and production (UNGDP) has outpaced research on the potential health impacts associated with the process. The Maryland Marcellus Shale Public Health Study was conducted to inform the Maryland Marcellus Shale Safe Drilling Initiative Advisory Commission, State legislators and the Governor about potential public health impacts associated with UNGDP so they could make an informed decision that considers the health and well-being of Marylanders. In this paper, we describe an impact assessment and hazard ranking methodology we used to assess the potential public health impacts for eight hazards associated with the UNGDP process. The hazard ranking included seven metrics: 1) presence of vulnerable populations (e.g. children under the age of 5, individuals over the age of 65, surface owners), 2) duration of exposure, 3) frequency of exposure, 4) likelihood of health effects, 5) magnitude/severity of health effects, 6) geographic extent, and 7) effectiveness of setbacks. Overall public health concern was determined by a color-coded ranking system (low, moderately high, and high) that was generated based on the overall sum of the scores for each hazard. We provide three illustrative examples of applying our methodology for air quality and health care infrastructure which were ranked as high concern and for water quality which was ranked moderately high concern. The hazard ranking was a valuable tool that allowed us to systematically evaluate each of the hazards and provide recommendations to minimize the hazards.