The induction of sun and shade leaves of the European beech (Fagus sylvatica L.): anatomical studies

Summary Primordia from buds of sun and shade twigs of European beech (Fagus sylvatica L.) were collected six times a year for anatomical investigations. Differentiation into sun-leaf and shade-leaf primordia was first observed in early August. Sun-leaf primordia had five, and shade-leaf primordia four layers of mesophyll meristem cells. With potted graft unions of beeches possible structural changes of leaf primordia were investigated. Trees adapted to shade develop sun-leaf primordia when put into full daylight, provided the transfer happened before July. Trees adapted to full daylight developed leaf primordia which remained structurally sun-leaf primordia when the plant was kept under shade conditions. Shadeleaf branches of young beech trees cut in February in order to expose the shade buds to full daylight developed either shade leaves or intermediate shade/sun leaves. These experiments show that the subtending leaf may provide the developing axillary bud with photoassimilates, but its character, whether sun or shade leaf, has no influence on the character of the developing leaf primordia.     

Influence of various factors on quantitative composition of leaf monoterpenes ofPicea abies (L.) Karst

Summary The extractable monoterpenes from needles of two groups of trees — 4-year-old clonal and 20-year-old wild trees — were studied with respect to the influence of individual constitution, needle age, whorl position, and position on branch. Leaf terpene amounts from clonal trees are significantly affected by age and position of the whorl, whereas position on the branch is of minor importance. Developing needles of clonal trees are most strongly affected by age and whorl position and they differ markedly from mature needles in quantitative terpene composition. Wild trees exhibit a very high variation from tree to tree, which obscures the influence of needle age and position. For this reason meaningful tree leaf terpene data will only be derived if large samples of needles of different ages are collected from distinct positions. When comparing different trees, needles should be selected that not only have the same state of development, but also originate from identical positions and have been subjected to the same light treatment.     

Novel Potential Interacting Partners of Fibronectin in Spontaneous Animal Model of Interstitial Cystitis

Feline idiopathic cystitis (FIC) is the only spontaneous animal model for human interstitial cystitis (IC), as both possess a distinctive chronical and relapsing character. Underlying pathomechanisms of both diseases are not clearly established yet. We recently detected increased urine fibronectin levels in FIC cases. The purpose of this study was to gain further insight into the pathogenesis by assessing interacting partners of fibronectin in urine of FIC affected cats. Several candidate proteins were identified via immunoprecipitation and mass spectrometry. Considerable changes in FIC conditions compared to physiological expression of co-purified proteins were detected by Western blot and immunohistochemistry. Compared to controls, complement C4a and thioredoxin were present in higher levels in urine of FIC patients whereas loss of signal intensity was detected in FIC affected tissue. Galectin-7 was exclusively detected in urine of FIC cats, pointing to an important role of this molecule in FIC pathogenesis. Moderate physiological signal intensity of galectin-7 in transitional epithelium shifted to distinct expression in transitional epithelium under pathophysiological conditions. I-FABP expression was reduced in urine and urinary bladder tissue of FIC cats. Additionally, transduction molecules of thioredoxin, NF-κB p65 and p38 MAPK, were examined. In FIC affected tissue, colocalization of thioredoxin and NF-κB p65 could be demonstrated compared to absent coexpression of thioredoxin and p38 MAPK. These considerable changes in expression level and pattern point to an important role for co-purified proteins of fibronectin and thioredoxin-regulated signal transduction pathways in FIC pathogenesis. These results could provide a promising starting point for novel therapeutic approaches in the future.     

ENVIRONMENTAL AND GENETIC CONTROL OF BRAIN AND SONG STRUCTURE IN THE ZEBRA FINCH

Birdsong is a classic example of a learned trait with cultural inheritance, with selection acting on trait expression. To understand how song responds to selection, it is vital to determine the extent to which variation in song learning and neuroanatomy is attributable to genetic variation, environmental conditions, or their interactions. Using a partial cross fostering design with an experimental stressor, we quantified the heritability of song structure and key brain nuclei in the song control system of the zebra finch and the genotype‐by‐environment (G × E) interactions. Neuroanatomy and song structure both showed low levels of heritability and are unlikely to be under selection as indicators of genetic quality. HVC, in particular, was almost entirely under environmental control. G × E interaction was important for brain development and may provide a mechanism by which additive genetic variation is maintained, which in turn may promote sexual selection through female choice. Our study suggests that selection may act on the genes determining vocal learning, rather than directly on the underlying neuroanatomy, and emphasizes the fundamental importance of environmental conditions for vocal learning and neural development in songbirds.     

Specific localisation of gap junction protein connexin 32 in the gastric mucosa of horses

In the glandular stomach, gap junctional intercellular communication (GJIC) plays an important role in the gastric mucosal defense system, and loss of GJIC is associated with ulcer formation. In spite of the high incidence of gastric ulcers in horses, particularly at pars nonglandularis, the presence of gap junctions in the equine stomach has not yet been studied. The objective was to obtain basic data on the distribution of gap junction protein connexin 32 (Cx32) in the different regions of normal equine gastric mucosa. Samples of mucosa were taken from seven horses at cardiac, fundic, and pyloric region and pars nonglandularis. To detect Cx32, immunohistochemical staining and Western blot analysis were performed. Corresponding mRNA was shown by RT-PCR and localised in tissue sections by in situ hybridisation. Cx32 was found in the glandular regions, whereas it was not detectable in squamous mucosa. Within the glandular epithelium, Cx32 was abundant in surface and foveolar cells and decreased towards the proliferative zone of the glands. These results suggest that gap junctions develop during the maturation of surface cells. Whether the lack of Cx32 at pars nonglandularis contributes to its susceptibility for developing ulcers, has to be further elucidated.     

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.     

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.