Insect ecology and veteran trees

Insect and veteran trees are important parts of ecosystems and are usually included in ecological studies of forest management. The loss of veteran trees in woodlands and open landscapes would lead to the loss of saproxylic organisms—an important part of biodiversity. Hence, the persistence of many specialized insects depends on the presence of veteran trees scattered in woodlands (e.g. ancient wood pastures, game parks or protected areas), cities, towns and villages (e.g. avenues, parks or chateau parks) or open landscapes (e.g. fishpond dams, solitary trees or fruit orchards). Veteran tree conditions could be fairly well described by three components—diameter, age and microhabitats present. The problem is that diameter belongs to the most studied characteristics, while age and microhabitats, which can be quite complicated to measure, are much less studied. This paper illustrates that, due to this unbalanced use of indicators of veteran-tree conditions, we are still missing some important information on saproxylic species ecology—and sometimes only large trees might be studied, rather than real veterans. Although we already know that veteran trees are essential habitat for a range of saproxylic organisms, there are still gaps in our knowledge of the specific conditions that veteran trees provide. It is vital that these are quantified and understood so that this information can be used to conserve veteran trees and their associated species.     

Substrate Locking Promotes Dimer-Dimer Docking of an Enzyme Antibiotic Target

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Endozoochorous seed dispersal by free-ranging herbivores in an abandoned landscape

Seed dispersal is a crucial process for the dynamics and maintenance of plant populations. Free-ranging animals are effective dispersal vectors because they can move between similar habitats and transport seeds into favourable environments. Dung samples from two species of common free-ranging mammals—deer and wild boar—were used to study endozoochorous dispersal of seeds in a military training area in western Bohemia. The area was abandoned after WWII, and the military training area was established in 1953. The vegetation consists of shrublands and dry grasslands. Data on the local species pool of grassland herbs and forbs were collected to compare the characteristics of dispersed versus non-dispersed plants. Deer and wild boar dispersed 84 plant species; however, species composition of seedlings emerging from dung samples showed significant differences between dispersal vectors and notable change across the growing season. 80% of all seedlings extracted from the dung samples belonged to stinging nettle, Urtica dioica. From trait analyses, seeds of endozoochorous plants had a higher longevity index in the soil seed bank than non-endozoochorous plants and more often possessed a mucilaginous surface. Our results show that deer and boar are successful, though not substitutable dispersers.     

Associations of HSP90AA2 gene polymorphisms with disease susceptibility,glucocorticoids efficacy and health-related quality of life in Chinese systemic lupus erythematosus patients

Although the current glucocorticoids (GCs) treatment for systemic lupus erythematosus (SLE) is effective to a certain extent, the difference in therapeutic effect between patients is still a widespread problem. Some patients can have repeated attacks that greatly diminish their quality of life. This study was conducted to investigate the relationship between HSP90AA2 polymorphisms and disease susceptibility, GCs efficacy and health-related quality of life (HRQoL) in Chinese SLE patients. A case–control study was performed in 470 SLE patients and 470 normal controls. Then, 444 patients in the case group were followed up for 12 weeks to observe efficacy of GCs and improvement of HRQoL. Two single nucleotide polymorphisms (SNPs) of HSP90AA2 were selected for genotyping: rs1826330 and rs6484340. HRQoL was assessed using the SF-36 questionnaire. The minor T allele of rs1826330 and the TT haplotype formed by rs1826330 and rs6484340 showed associations with decreased SLE risk (T allele: P_BH?=?0.022; TT haplotype: P_BH?=?0.033). A significant association between rs6484340 and improvement of HRQoL was revealed in the follow-up study. Five subscales of SF-36 were appeared to be influenced by rs6484340: total score of SF-36 (additive model: P_BH?=?0.026), physical function (additive model: P_BH?=?0.026), role-physical (recessive model: P_BH?=?0.041), mental health (dominant model: P_BH?=?0.047), and physical component summary (additive model: P_BH?=?0.026). No statistical significance was found between HSP90AA2 gene polymorphisms and GCs efficacy. These results revealed a genetic association between HSP90AA2 and SLE. Remarkably, HSP90AA2 has an impact on the improvement of HRQoL in Chinese population with SLE.     

Duloxetine Protects Human Neuroblastoma Cells from Oxidative Stress-Induced Cell Death Through Akt/Nrf-2/HO-1 Pathway

The contribution of oxidative stress to the pathophysiology of depression has been described in numerous studies. Particularly, an increased production of reactive oxygen species (ROS) caused by mitochondrial dysfunction can lead to neuronal cell death. Human neuroblastoma SH-SY5Y cells were used to investigate the neuroprotective effect of the antidepressant duloxetine against rotenone-induced oxidative stress. SH-SY5Y cells were pretreated with duloxetine (1–5 µM) for 24 h followed by a 24-h rotenone exposure (10 µM). The phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) inhibitor LY294002 (10 µM) and the heme oxygenase 1 (HO-1) inhibitor zinc protoporphyrin IX-ZnPP (5 µM) were added to cultures 1 h prior duloxetine treatments. After treatments cell viability and ROS generation were assessed. NF-E2-related factor-2 (Nrf2) nuclear translocation was assessed by immunofluorescent staining after 4 and 8 h of duloxetine incubation. Furthermore, the Nrf2 and HO-1 mRNA expression was carried out after 4–48 h of duloxetine treatment by qRT-PCR. Duloxetine pretreatment antagonized rotenone-induced overproduction of ROS and cell death in SH-SY5Y cells. In addition, a 1-h pretreatment with LY294002 abolished duloxetine’s protective effect. Duloxetine also induced nuclear translocation of the Nrf2 and the expression of its target gene, HO-1. Finally, the HO-1 inhibitor, ZnPP, suppressed the duloxetine protective effect. Overall, these results indicate that the mechanism of duloxetine neuroprotective action against oxidative stress and cell death might rely on the Akt/Nrf2/HO-1 pathways.     

Influence of ionic strength on the stability of phage t2r to osmotic shock

The authors assume that an increase in the ionic strength of the medium results in dissociation of the DNA-polyamine complex in the phage head. The released polyamines and internal protein molecules are unable to permeate into the external environment. Their thermal movement causes constant pressure within the phage; this contributes to rupture of the head by osmotic shock and probably plays a decisive role in injection of the phage DNA into the bacterium. Study of osmotic shock by glycerol in media of different ionic strengths showed that, as the ionic strength increases, the bacteriophage is at first destabihized by the action of the released polyamines and that only when the ionic strength is raised still further, it is restabilized by the influence of the ionic strength on the resistance of the membrane. The osmotic prossures required to rupture the phage head are practically the same for NaCl and KCl solutions, while for shock by glycerol solutions, considerably lower values were measured in media of low ionic strengths. The authors attribute these differences to differences in the rate of permeation of the shocking substance across the phage membrane. The equilibrium for NaCl and KCl is established in less than one minute and for glycerol in 5–10 min.