Salivary isoprostanes indicate increased oxidation injury in periodontitis with additional tobacco abuse

Isoprostanes (IPs) are indicators of in-vivo oxidative stress, and have been successfully used as markers for chronic inflammatory processes. The presence of chronic periodontal disease and cigarette smoking has been individually linked to the development of atherosclerosis, yet data regarding oxidative stress in this context are not available yet. The aim of this study was to evaluate levels of the salivary prostaglandins (PGs) 8-epi-PGF(2alpha), 6-oxo-PGF(1alpha), thromboxane B(2) (TXB(2)) and PGF(2alpha) in association with periodontal disease status with and without additional cigarette smoking. We analyzed saliva samples from 121 adults, (aged 21-73 years, 90 non-smokers, 31 smokers) for levels of 8-epi-PGF(2alpha), 6-oxo-PGF(1alpha), TXB(2) and PGF(2alpha). On the basis of periodontal disease indices the periodontal status of each subject was assessed and outcomes were then correlated with smoking status and laboratory findings. Salivary 8-epi-PGF(2alpha) levels increased with deteriorating plaque index, and were significantly higher (115.5 +/- 23.5 pg/ml) in smoking individuals, when compared to non-smokers (70.2 +/- 20.4 pg/ml, p<0.0001). In addition, smokers showed higher TXB(2) and PGF(2alphas) and lower 6-oxo-PGF(1alpha) levels p<0.0001). Oxidative stress, as reflected by elevated salivary 8-epi-PGF(2alpha) levels, is associated with the extent of periodontal disease and is significantly aggravated by concomitant tobacco abuse. Chronic inflammation and smoking have been individually associated with the development of atherosclerosis. The results of this study indicate that: 1) salivary IPs can reliably assess the degree of oxidative stress, and: 2) smoking and periodontal disease are two modifiable cardiovascular risk factors, able to potentiate each other.     

Bird navigation: what type of information does the magnetite-based receptor provide?

Previous experiments have shown that a short, strong magnetic pulse caused migratory birds to change their headings from their normal migratory direction to an easterly direction in both spring and autumn. In order to analyse the nature of this pulse effect, we subjected migratory Australian silvereyes, Zosterops lateralis, to a magnetic pulse and tested their subsequent response under different magnetic conditions. In the local geomagnetic field, the birds preferred easterly headings as before, and when the horizontal component of the magnetic field was shifted 90 degrees anticlockwise, they altered their headings accordingly northwards. In a field with the vertical component inverted, the birds reversed their headings to westwards, indicating that their directional orientation was controlled by the normal inclination compass. These findings show that although the pulse strongly affects the magnetite particles, it leaves the functional mechanism of the magnetic compass intact. Thus, magnetite-based receptors seem to mediate magnetic 'map'-information used to determine position, and when affected by a pulse, they provide birds with false positional information that causes them to change their course.     

Impaired wound healing in mice lacking the basement membrane protein nidogen 1

Nidogens 1 and 2 are ubiquitous basement membrane (BM) components, whose interactions in particular with laminin, collagen IV and perlecan have been considered important for BM formation. Genetic deletion of either NID gene does not reveal BM alterations suggesting compensatory roles for nidogens 1 and 2. However, neurological deficits in nidogen 1 null mice, not seen in the absence of nidogen 2, also suggest isoform specific functions. To test this further, skin wound healing which requires BM reformation was studied in adult nidogen 1 deficient mice. Although re-epithelialization was not altered, the newly formed epidermis showed marked hyperproliferation and a delay in differentiation at day 10 post injury. Distinct to control wounds, there was also considerable α-smooth muscle actin staining in the dermis of nidogen 1 deficient wounds at this time point. Further, laminin deposition and distribution of the β1 and β4 integrin chains were also significantly altered whereas the deposition of other BM components, including nidogen 2, was unchanged. Surprisingly, these differences between control and mutant wounds at day 10 post wounding did not affect the ultrastructural appearance of the dermo-epidermal BM suggesting a non-structural role for nidogen 1 in wound repair.     

Longitudinal changes in muscle power compared to muscle strength and mass

Objectives:The study reports longitudinal changes in grip strength, muscle mass and muscle power of lower extremities. The aim is to identify early muscular changes to improve the diagnosis and treatment of sarcopenia.Methods:Grip strength was measured by hand dynamometer, muscle mass by dual-energy X-ray absorptiometry and muscle power by performing a chair rise test and two-leg jumps (2LJP) on the Leonardo Mechanograph®. Longitudinal changes were analysed using paired t-tests by age group and sex. Differences between groups in terms of the annual change were tested by Analysis of Variance and the Dunnett’s test. Comparisons between the variables were performed using one sample t-tests.Results:Six-year changes were determined in 318 randomly selected healthy participants aged 20-90 years from Berlin. 2LJP declined significantly earlier in 20-39 years old women (-3.70 W/kg) and men (-5.97 W/kg, both p<0.001). This is an absolute annual decline of -0.46 W/kg in females and -0.75 W/kg in males. In the oldest age group, 2LJP showed the highest absolute annual loss with -0.99 W/kg in women and -0.88 W/kg in men. 2LJP was significantly different compared to all variables of muscle mass and strength (p<0.01).Conclusions:The results underline the importance of assessing muscle power using 2LJP during aging.     

GFP-Atg8 protease protection as a tool to monitor autophagosome biogenesis

Perhaps the most complex step of macroautophagy is the formation of the double-membrane autophagosome. The majority of the autophagy-related (Atg) proteins are thought to participate in nucleation and expansion of the phagophore, and/or the completion of this compartment. Monitoring this part of the process is difficult, and typically involves electron microscopy analysis; however, unless three-dimensional tomography is performed, even this method cannot be used to easily determine if the phagophore is completely enclosed. Accordingly, a complementary approach is to examine the accessibility of sequestered cargo to exogenously added protease. This type of protease protection analysis has been used to monitor the formation of cytoplasm-to-vacuole targeting (Cvt) vesicles and autophagosomes by examining the protease sensitivity of precursor aminopeptidase I (prApe1). For determining the status of autophagosomes formed during nonselective autophagy, however, prApe1 is not the best marker protein. Here, we describe an alternative method for examining autophagosome completion using GFP-Atg8 as a marker for protease protection.     

Avian ultraviolet/violet cones identified as probable magnetoreceptors

Background

The Radical-Pair-Model postulates that the reception of magnetic compass directions in birds is based on spin-chemical reactions in specialized photopigments in the eye, with cryptochromes discussed as candidate molecules. But so far, the exact subcellular characterization of these molecules in the retina remained unknown.

Methodology/Principal Findings

We here describe the localization of cryptochrome 1a (Cry1a) in the retina of European robins, Erithacus rubecula, and domestic chickens, Gallus gallus, two species that have been shown to use the magnetic field for compass orientation. In both species, Cry1a is present exclusively in the ultraviolet/violet (UV/V) cones that are distributed across the entire retina. Electron microscopy shows Cry1a in ordered bands along the membrane discs of the outer segment, and cell fractionation reveals Cry1a in the membrane fraction, suggesting the possibility that Cry1a is anchored along membranes.

Conclusions/Significance

We provide first structural evidence that Cry1a occurs within a sensory structure arranged in a way that fulfils essential requirements of the Radical-Pair-Model. Our findings, identifying the UV/V-cones as probable magnetoreceptors, support the assumption that Cry1a is indeed the receptor molecule mediating information on magnetic directions, and thus provide the Radical-Pair-Model with a profound histological background.     

General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types

Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider larger spatial scales and different land-use types.