Dictyocaulus viviparus: Migration in agar of larvae subjected to a variety of physicochemical exposures

Dictyocaulus viviparus larvae were exposed to ox bile and CO₂ at intervals during their cultivation to the infective stage. Preinfective and young infective larvae were stimulated by CO₂. Bile slightly inhibited preinfective larvae, but stimulated the infective stage. Old coiled, resting infective larvae were stimulated by bile down to a concentration of 10 ppm of bile dry matter, by vertebrate biles of pig, sheep, newborn calf, cow, guinea pig, dog, and chicken, as well as by defatted bile dry matter and by glyco-, tauro-, glycodeoxy-, and taurodeoxycholates. Continuous bile exposure appeared necessary to maintain high larval activity. A high pCO₂ as well as a low redox potential potentiated the effect of bile, but had no effect alone. Exposure to pepsin-HCl and to trypsin had only a minor stimulatory effect.     

Alpha 2-C10 adrenergic receptors expressed in rat 1 fibroblasts can regulate both adenylylcyclase and phospholipase D-mediated hydrolysis of phosphatidylcholine by interacting with pertussis toxin-sensitive guanine nucleotide-binding proteins.

The alpha 2-C10 adrenergic receptor from human platelets was expressed permanently in Rat-1 fibroblasts. A series of clones that varied in expression of the receptor from 0 to 3.5 pmol/mg of membrane protein were isolated. We have demonstrated recently in cells of one of these clones (1C) that the alpha 2-C10 receptor interacts directly with two distinct pertussis toxin-sensitive G-proteins, Gi2 and Gi3 (Milligan, G., Carr, C., Gould, G. W., Mullaney, I., and Lavan, B.E. (1991) J. Biol. Chem. 266, 6447-6455). High affinity GTPase activity in membranes of cells from the various clones was stimulated by the addition of the alpha 2-adrenergic agonist UK14304, defining that the receptor coupled productively to the G-protein signaling system. Maximal stimulation of high affinity GTPase activity correlated with the levels of receptor expressed. Clones expressing the receptor also demonstrated agonist-mediated inhibition of adenylylcyclase. Futhermore, the alpha 2-C10 receptor in one clone (1C), but not other clones, promoted a marked stimulation in the generation of water-soluble products derived from phosphatidylcholine. The concentration of UK14304 required to produce half-maximal regulation of GTPase activity (20-30 nM), of forskolin-amplified adenylylcyclase activity (30-40 nM), and of choline generation (30-40 nM) were similar. Transphosphatidylation experiments with cells of clone 1C indicated that the receptor-mediated hydrolysis of phosphatidylcholine was via the action of a phospholipase D. All of these effects were attenuated by pretreatment of the cells with pertussis toxin. Dose-effect curves of pertussis toxin-treatment demonstrated similar effective concentrations of the toxin in causing endogenous ADP-ribosylation of both Gi2 and Gi3, inhibition of receptor-stimulated GTPase activity, and phospholipase D activity. Receptor activation of phospholipase D activity was not dependent upon prior phospholipase C-dependent activation of protein kinase C, as alpha 2-adrenergic stimulation of inositol phosphate production was negligible and the presence of the selective protein kinase C inhibitor RO-31-8220, at concentrations up to 10 microM, had no effect on UK14304-mediated production of phosphatidylbutanol. These results demonstrate that expression of the alpha 2-C10 receptor in a heterologous system can result in receptor regulation of signaling elements that appear not to be primary targets for the receptor in vivo. Such results are important in respect to recent observations that transfection of a single defined receptor into separate cell lines can lead to the regulation of distinct effector systems (Vallar, L., Muca, C., Magni, M., Albert, P., Bunzow, J., Meldolesi, J. and Civelli, O. (1990) J. Biol. Chem. 265, 10320-10326).(ABSTRACT TRUNCATED AT 400 WORDS)     

Cystine accumulation in cystinotic fibroblasts from free and protein-linked cystine but not cysteine

The accumulation of cystine in cystinotic fibroblasts from free and protein-linked cystine has been investigated. Cystine is not accumulated from cysteine but is readily accumulated from cystine. The accumulation from free cystine does not occur as a result of pinocytosis or from the degradation of a rapidly metabolized protein pool. Further studies of the degradation of disulphide-containing proteins by these cells may aid understanding of the mechanisms of proteolysis.     

Efficacy of Indolicidin,Cecropin A (1-7)-Melittin (CAMA) and Their Combination Against Biofilm-Forming Multidrug-Resistant Enteroaggregative Escherichia coli

The present study examined the anti-biofilm efficacy of two short-chain antimicrobial peptides (AMPs), namely, indolicidin and cecropin A (1-7)-melittin (CAMA) against biofilm-forming multidrug-resistant enteroaggregative Escherichia coli (MDR-EAEC) isolates. The typical EAEC isolates re-validated by PCR and confirmed using HEp-2 cell adherence assay was subjected to antibiotic susceptibility testing to confirm its MDR status. The biofilm-forming ability of MDR-EAEC isolates was assessed by Congo red binding, microtitre plate assays and hydrophobicity index; broth microdilution technique was employed to determine minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentrations (MBECs). The obtained MIC and MBEC values for both AMPs were evaluated alone and in combination against MDR-EAEC biofilms using crystal violet (CV) staining and confocal microscopy-based live/dead cell quantification methods. All the three MDR-EAEC strains revealed weak to strong biofilm-forming ability and were found to be electron-donating and weakly electron-accepting (hydrophobicity index). Also, highly significant (P < 0.001) time-dependent hydrodynamic growth of the three MDR-EAEC strains was observed at 48 h of incubation in Dulbecco’s modified Eagle’s medium (DMEM) containing 0.45% D-glucose. AMPs and their combination were able to inhibit the initial biofilm formation at 24 h and 48 h as evidenced by CV staining and confocal quantification. Further, the application of AMPs (individually and combination) against the preformed MDR-EAEC biofilms resulted in highly significant eradication (P < 0.001) at 24 h post treatment. However, significant differences were not observed between AMP treatments (individually or in combination). The AMPs seem to be an effective candidates for further investigations such as safety, stability and appropriate biofilm-forming MDR-EAEC animal models.

     

Risk of Inflammatory Bowel Disease According to Self-Rated Health,Pregnancy Course,and Pregnancy Complications: A Study within the Danish National Birth Cohort

Background

Poor self-rated health (SRH) has been connected to immunological changes, and pregnancy complications have been suggested in the etiology of autoimmune diseases including inflammatory bowel disease (IBD). We evaluated the impact of self-rated pre-pregnancy health and pregnancy course, hyperemesis, gestational hypertension, and preeclampsia on risk of IBD.

Methods

Information was collected by questionnaires from The Danish National Birth Cohort (enrolment 1996–2002) at 16^th and 30^th week of pregnancy and 6 months postpartum. A total of 55,699 women were followed from childbirth until development of IBD (using validated National Hospital Discharge Register diagnoses), emigration, death, or end of follow-up, 31^st of October, 2011. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated using Cox proportional hazards models adjusting for age and evaluating pre-pregnancy BMI, parity, alcohol and tobacco consumption, and socio-occupational status as potential confounders.

Results

Risk of IBD increased with decreasing level of self-rated pre-pregnancy health (p = 0.002) and was elevated in women with poor self-rated pregnancy course (HR, 1.61, 95% CI 1.22–2.12). Associations persisted for more than 5 years postpartum. Hyperemesis and preeclampsia were not significantly associated with risk of IBD.

Conclusions

This is the first prospective observational study to suggest that poor self-rated health – in general and in relation to pregnancy – is associated with increased risk of IBD even in the long term though results needs further confirmation. Symptoms of specific pregnancy complications were, on the other hand, not significantly associated with risk of IBD.     

Meeting Report on the Conference on Fathers’ Role in Children’s Weight‐Related Behaviors and Outcomes

On September 22, 2017, “Engaging the Forgotten Parent: Conference of Experts on Fathers’ Role in Children’s Weight‐Related Behaviours and Outcomes” brought researchers, students, health professionals, community stakeholders, and knowledge users from Canada, Australia, and the United States together to Toronto, Ontario, for a 1‐day gathering focused on furthering scientific understanding of effective strategies to recruit, engage, and retain fathers in family‐based obesity research. Furthermore this conference focused on identifying key knowledge gaps and opportunities for collaborative research to further our understanding of fathers’ roles in the development of their children’s behaviors and weight outcomes. The following four themes emerged from the conference: (1) underrepresentation of fathers in family‐based obesity research, (2) fathers’ engagement in children’s weight‐related behaviors and desire to participate in research, (3) best practices in recruiting, engaging, and retaining fathers in research, and (4) key lessons learned from fatherhood research in developmental science.     

Ecology of Listeria monocytogenes and Listeria species in India: the occurrence,resistance to biocides,genomic landscape and biocontrol

Listeria monocytogenes, the causative agent of listeriosis, has been implicated in increasing foodborne outbreaks worldwide. The disease is manifested in various forms ranging from severe sepsis in immune-compromised individuals, febrile gastroenteritis, still birth, abortions and meningoencephalitis. In India, data from studies on the detection and molecular epidemiological analysis of L. monocytogenes are only recently emerging. The presence of Listeria in different ecological niches has been recorded from India, including foods, soil, vegetables, mangrove swamps, seafood, freshwater fishes, clinical cases, and also insects. The organism has also been isolated from women with spontaneous abortions, miscarriage or recurrent obstetric history, aborted foetuses, animal clinical cases and wildlife samples. A novel species of Listeria has also been characterized. Listeria monocytogenes strains isolated from clinical, environmental, and foods showed biofilm-forming abilities. Listeria monocytogenes serotype 4b isolates of ST328, a predominant and unique ST observed in India, was repeatedly isolated from different sources, times, and geographical locations. Here, we reviewed the occurrence of Listeria in different sources in India, its resistance to biocides, and provide epidemiological analysis on its genomic landscape.     

Regulation of the mitogen-activated protein kinase signaling pathway by SHP2.

Gab1-SHP2 association is required for Erk mitogen-activated protein kinase activation by several growth factors. Gab1-SHP2 interaction activates SHP2. However, an activated SHP2 still needs to associate with Gab1 to mediate Erk activation. It was unclear whether SHP2 is required to dephosphorylate a negative phosphorylation site on Gab1 or whether SHP2 needs the Gab1 pleckstrin homology (PH) domain to target it to the plasma membrane. We found that expression of a fusion protein consisting of the Gab1 PH domain and an active SHP2 (Gab1PH-SHP2DeltaN) induced constitutive Mek1 and Erk2 activation. Linking the active SHP2DeltaN to the PDK1 PH domain or the FRS2beta myristoylation sequence also induced Mek1 activation. Mek1 activation by Gab1PH-SHP2DeltaN was inhibited by an Src inhibitor and by Csk. Significantly, Gab1PH-SHP2DeltaN induced Src activation. Gab1PH-SHP2DeltaN expression activated Ras, and the Gab1PH-SHP2DeltaN-induced Mek1 activation was blocked by RasN17. These findings suggest that Gab1PH-SHP2DeltaN activated a signaling step upstream of Src and Ras. The SHP2 tyrosine phosphatase activity is essential for the function of the fusion protein. Together, these data show that the Gab1 sequence, besides the PH domain and SHP2 binding sites, is dispensable for Erk activation, suggesting that the primary role of Gab1 association with an activated SHP2 is to target it to the membrane.