DNA triplex stabilization by a delta-carboline derivative tethered to third strand oligonucleotides

A delta-carboline derivative was covalently coupled to a 7 mer oligonucleotide at its 5'- or 3'-end. The stability of triplexes formed from the conjugates and a double-helical target was studied by UV melting experiments. Compared to the unmodified control triple helices, triplexes with the conjugate exhibit a significantly higher stability. However, the degree of stabilization depends on the particular triplex structure formed.     

Design and expression of peptides with antimicrobial activity against Salmonella typhimurium

We showed previously that insertion of Synechocystis Δ¹²‐desaturase in salmonella's membrane alters membrane physical state (MPS), followed by the expression of stress genes causing inability to survive within murine macrophages (MΦ). Recently, we showed that expression of one membrane lipid domain (MLD) of Δ¹²‐desaturase (ORF200) interferes with salmonella MPS, causing loss of virulence in mice and immunoprotection. Here, we postulate that an α‐antimicrobial peptide (α‐AMP) intercalates within membrane lipids, and depending on its amino acid sequence, it does so within specific key sensors of MLD. In this study, we choose as target for a putative synthetic AMP, PhoP/PhoQ, a sensor that responds to low Mg²⁺ concentration. We synthesised a modified DNA fragment coding for an amino acid sequence (NUF) similar to that fragment and expressed it in salmonella typhimurium. We showed that the pattern of gene expression controlled by PhoP/PhoQ highlights dysregulation of pathways involving phospholipids biosynthesis, stress proteins and genes coding for antigens. RNA‐Seq of strain expressing ORF200 showed that the pattern of those genes is also altered here. Accumulation of NUF conferred temporary immunoprotection. This represents a powerful procedure to address synthetic α‐AMPs to a specific MLD generating live non‐virulent bacterial strains.     

Predicting cortisol stress responses in older individuals: influence of serotonin receptor 1A gene (HTR1A) and stressful life events

Considerable variability in the activity of the hypothalamus-pituitary-adrenal (HPA) axis in response to stress has been found in quantitative genetic studies investigating healthy individuals suggesting that at least part of this variance is due to genetic factors. Since the HPA axis is regulated by a neuronal network including amygdala, hippocampus, prefrontal cortex as well as brainstem circuits, the investigation of candidate genes that impact neurotransmitter systems related to these brain regions might further elucidate the genetic underpinnings of the stress response. However, aside from genetic risk factors, past stressful life events might also result in long-term adjustments of HPA axis reactivity. Here, we investigated the effects of the − 1019 G/C polymorphism in the HTR1A gene encoding the serotonin (5-HT) receptor 1A (5-HT_1A) and stressful life events experienced during childhood and adolescence on changes in cortisol levels in response to the Trier Social Stress Test (TSST) in a sample of healthy older adults (N = 97). Regression analyses revealed a significant effect of HTR1A genotype with the G allele being associated with a less pronounced stress response. In addition, an inverse relationship between past stressful life events and cortisol release but no gene × environment interaction was detected. The results further underscore the crucial role of functional serotonergic genetic variation as well as stressful events during critical stages of development on the acute stress response later in life.     

Increased HEV Seroprevalence in Patients with Autoimmune Hepatitis

Background

Hepatitis E virus (HEV) infection takes a clinically silent, self-limited course in the far majority of cases. Chronic hepatitis E has been reported in some cohorts of immunocompromised individuals. The role of HEV infections in patients with autoimmune hepatitis (AIH) is unknown.

Methods

969 individuals were tested for anti-HEV antibodies (MP-diagnostics) including 208 patients with AIH, 537 healthy controls, 114 patients with another autoimmune disease, rheumatoid arthritis (RA), and 109 patients with chronic HCV- or HBV-infection (HBV/HCV). Patients with AIH, RA and HBV/HCV were tested for HEV RNA. HEV-specific proliferative T cell responses were investigated using CFSE staining and in vitro stimulation of PBMC with overlapping HEV peptides.

Results

HEV-antibodies tested more frequently positive in patients with AIH (n = 16; 7.7%) than in healthy controls (n = 11; 2.0%; p = 0.0002), patients with RA (n = 4; 3.5%; p = 0.13) or patients with HBV/HCV infection (n = 2; 2.8%; p = 0.03). HEV-specific T cell responses could be detected in all anti-HEV-positive AIH patients. One AIH patient receiving immunosuppression with cyclosporin and prednisolone and elevated ALT levels had acute hepatitis E but HEV viremia resolved after reducing immunosuppressive medication. None of the RA or HBV/HCV patients tested HEV RNA positive.

Conclusions

Patients with autoimmune hepatitis but not RA or HBV/HCV patients are more likely to test anti-HEV positive. HEV infection should been ruled out before the diagnosis of AIH is made. Testing for HEV RNA is also recommended in AIH patients not responding to immunosuppressive therapy.     

The Challenge of Living On: Psychopathology and Its Mediating Influence on the Readjustment of Former Child Soldiers

Current civil wars are characterized by the increasing involvement of civilian populations and the systematic employment of child soldiers. An example of such wars was the conflict in Northern Uganda, where the war-affected population is still challenged by the reintegration of formerly abducted children and youths. A cross-sectional, population-based survey, using a multistage cluster sampling approach of 1,113 Northern Ugandans aged between 12 and 25 in camps for internally displaced persons and locally validated instruments was conducted to assess symptoms and diagnoses of Posttraumatic Stress Disorder (PTSD) and probable Depression in war-affected, as well as formerly abducted individuals. Further objectives were to determine predictors of psychopathology and to relate indicators of maladjustment (i.e., impairments in daily and community functioning, somatic complaints, suicidality, aggressiveness and discrimination) to abduction, level of exposure to violence and psychopathology. 43% of the sample reported abduction by the rebel army. Exposure to violence among this group was higher than for non-abducted youths (t = 28.05; p<.001). PTSD point prevalence rates were 25% among former child soldiers and 7% among the comparison group. High suicidal ideation was present in 16% and 6% respectively. A higher amount of experienced and witnessed event-types (β = . 32. p<.001), loss of first-degree relatives (β = .13. p<.001) and the number of event-types involving forced perpetration (β = .23. p<.001) were identified as risk factors of PTSD symptoms in former child soldiers. The associations between abductee-status and indicators of maladjustment were fully mediated by level of trauma exposure and psychopathology. Results show that child soldiering and its psychological sequelae affect a substantial proportion of children and youths. After release or flight, their readjustment depends at least partly on their level of mental traumatization.     

Social environment and weather during early life influence gastro-intestinal parasite loads in a group-living mammal

Conditions experienced during early life have been frequently shown to exert long-term consequences on an animal’s fitness. In mammals and birds, the time around and shortly after weaning is one of the crucial periods early in life. However, little is known about how social and abiotic environmental conditions experienced around this time affect fitness-related traits such as endoparasite loads. We studied consequences of social interactions and rainy weather conditions around and after weaning on gastro-intestinal nematode loads in juvenile European rabbits Oryctolagus cuniculus. Infestations with the gastric nematode Graphidium strigosum and with the intestinal nematode Passalurus ambiguus were higher in animals experiencing more rain during early life. This might have been due to the higher persistence of nematodes’ infective stages outside the host body together with the animals’ lower energy allocation for immune defence under more humid and thus energetically challenging conditions. In contrast, infestations with P. ambiguus were lower in animals with more positive social interactions with mother and litter siblings. We propose that social support provided by familiar group members buffered negative stress effects on immune function, lowering endoparasite infestations. This is supported by the negative correlation between positive social behaviour and serum corticosterone concentrations, indicating lower stress in juveniles which integrated more successfully into the social network of their group. In conclusion, the findings offer a pathway showing how differences in the abiotic environment and social life conditions experienced early in life could translate into long-term fitness consequences via the effects on endoparasite loads.