Effect of Pertussis Toxin on Radioligand Binding to Rat Brain Adenosine A1 Receptors

In a previous study we showed that in vivo treatment with pertussis toxin could inhibit some, but not all, effects of adenosine in the rat hippocampus. In this study we investigated the effect of pertussis toxin on the binding of adenosine analogues to A1 receptors in rat brain. Intraventricular injection of pertussis toxin (10 micrograms into the lateral ventricle) did not affect A1 receptor binding in any brain region studied, as evaluated by autoradiography. In vitro treatment of brain sections (10 microns) with pertussis toxin for 5 h, under conditions when greater than 80% of the G proteins were ADP ribosylated, did not alter radioligand binding to adenosine A1 receptors. GTP (10 microM) virtually abolished the high-affinity agonist binding to the A1 receptor. On the other hand, in solubilized cortical membrane preparations, pertussis toxin pretreatment induced a complete shift of the A1 receptors to the low-affinity state. This suggests that the ability of pertussis toxin to affect G proteins coupled to A1 receptors in brain depends not only on the distribution of the toxin but also on the configuration of receptors and G proteins.     

On polynuclear aromatic hydrocarbons contamination levels in the ecosystem of Lake Peipsi in the 1970s–1980s

The data on benzo(a)pyrene (BaP) and other polynuclear aromatic hydrocarbons (PAH) pollution of Lake Peipsi and its tributaries in the 1970s–1980s have been summarized. Systematic data on the pollution of Lake Peipsi by BaP are available. The BaP content in lake water varied from <0.1 to 237 ng 1^–1. The content and qualitative composition of PAH varied in different observations. PAH were accumulated mainly in the bottom sediments; in their surface layer BaP concentrations were 10³–10⁶ times higher than in water. The concentration of the PAH in bottom sediments varied from 16 to 580 µg kg^–1 in the lake and from 40 to 2800 µg kg^–1 in its tributaries. The content of BaP in fish and biota was not high. Among the pollution sources the atmospheric pollution played quite a significant role. The lake was also polluted by oil spillage and fuel exhausts from boats and ships. The PAH concentration in the water of the tributaries was somewhat higher than in the area of Lake Peipsi.     

Corticotropin-releasing factor differentially regulates proopiomelanocortin messenger ribonucleic acid levels in anterior as compared to intermediate pituitary lobes of rats

Chronic subcutaneous infusion of small doses (0.1 microgram/h) of ovine corticotropin-releasing factor (oCRF) into rats for 8 days resulted in differential alteration of proopiomelanocortin (POMC) mRNA levels in the individual pituitary lobes: In the anterior lobe POMC mRNA levels, quantitated by hybridisation using a 32P-labelled POMC cDNA probe, increased by about 80%, whereas in the intermediate/posterior lobe a marked decrease to about 30% of the initial levels was observed. Significant changes were found not earlier than 3 days following commencement of administration.     

Fluorescence staining of live cyanobacterial cells suggest non-stringent chromosome segregation and absence of a connection between cytoplasmic and thylakoid membranes

Background  

In spite of their abundance and importance, little is known about cyanobacterial cell biology and their cell cycle. During each cell cycle, chromosomes must be separated into future daughter cells, i.e. into both cell halves, which in many bacteria is achieved by an active machinery that operates during DNA replication. Many cyanobacteria contain multiple identical copies of the chromosome, but it is unknown how chromosomes are segregated into future daughter cells, and if an active or passive mechanism is operative. In addition to an outer and an inner cell membrane, cyanobacteria contain internal thylakoid membranes that carry the active photosynthetic machinery. It is unclear whether thylakoid membranes are invaginations of the inner cell membrane, or an independent membrane system.     

Effect of ellagic acid on growth and physiology of canola (Brassica napus L.) under saline conditions

Salinity stress is limiting growth and productivity of plants in many areas of the world. Plants adopted different strategies to minimize the effect of salt stress. A pot experiment was conducted to investigate the morphological and physiological changes produced in Canola (Brassica napus) by exogenous application of ellagic acid (EA) under saline conditions. EA is an antioxidant, expected to reduce the effect of salinity stress. The seeds of two canola cultivars, Rainbow and Oscar, were soaked for 6?h with different concentrations of EA (0, 55 and 110?µg/ml). The soaked seeds were sown in small pots. Salt stress was imposed on the plants by applying NaCl solutions of different concentrations (0, 60 and 120?mM) and the duration of stress was for four weeks. Salinity stress reduced seed germination and disturbed the morphological and physiological attributes of B. napus. Application of EA as seed soaking reduced the effect of salinity and enhanced the growth of plants. Overall, we could confirm a significant role of EA by inducing salinity tolerance in B. napus.     

Anti-HMGB1 auto-Abs influence fatigue in patients with Crohn’s disease

Fatigue is common in all chronic inflammatory and autoimmune diseases. A conceptual model for understanding the biological basis of fatigue describes it as being a part of the sickness behaviour response generated by pro-inflammatory cytokines and other mediators. We hypothesised that the pro-inflammatory high mobility group box 1 (HMGB1) protein is a fatigue-inducing molecule and that auto-Abs against HMGB1 reduce fatigue. We measured Abs against disulphide (ds) HMGB1 and fully reduced (fr) HMGB1 in plasma from 57 patients with Crohn’s disease. Fatigue was rated using the fatigue visual analogue scale (fVAS) and disease activity with faecal calprotectin, C-reactive protein and the Simple Endoscopic Score for Crohn’s disease. Multivariable regression models identified anti-dsHMGB1 and anti-frHMGB1 Abs as the strongest contributing factors for fVAS scores (B = −29.10 (P = 0.01), R² = 0.17, and B = −17.77 (P = 0.01), R² = 0.17, respectively). Results indicate that anti-HMGB1 auto-Abs alleviate fatigue possibly by down-regulating HMGB1-induced sickness behaviour.