Preventive action of organosilicon treatments against disfigurement of wood under laboratory and outdoor conditions

Organosilicons and biocides with known effectiveness against fungal disfigurement were used for dipping or impregnating Scots pine sapwood specimens. All specimens were artificially or naturally weathered and the colour of all specimens was determined with a spectrophotometer at fixed times. After artificial weathering the specimens were used in blue stain tests according to EN 152 or according to the EN 152 reverse method. The naturally exposed specimens were inspected for fungal disfigurement on their back side. Although the results learn that the coating approach is far better than the wood preservatives approach for evaluating blue stain attack of organosilicon-treated wood, organosilicons fail to protect wood under laboratory conditions. Outdoor exposure, however, revealed that organosilicon impregnated specimens were better protected against fungal disfigurement. The addition of a biocide improves the performance. Artificially aged specimens did not show significant colour differences compared to untreated Scots pine sapwood, while naturally aged specimens did, depending on the treatment conditions and presence of biocides. Organosilicons are able to reduce leaching of (degraded) wood constituents, leading to fewer colour changes compared to untreated scots pine and to decreased availability of nutrients for superficial fungal growth.     

Identification of a novel UDP-Glc:GlcNAc beta1-->4-glucosyltransferase in Lymnaea stagnalis that may be involved in the synthesis of complex-type oligosaccharide chains

Several studies suggest, that the snail Lymnaea stagnalis contains glycoproteins whose oligosaccharide side chains have structural features not commonly found in mammalian glycoproteins. In this study, prostate glands of L. stagnalis were incubated in media containing either [(3)H]-mannose, [(3)H]-glucosamine, or [(3)H]-galactose, and the metabolically radiolabeled protein-bound oligosaccharides were analyzed. The newly synthesized diantennary-like complex-type asparagine-linked chains contained a considerable amount of glucose, next to mannose, GlcNAc, fucose, galactose, and traces of GalNAc. Since glucose has not been found before as a constituent of diantennary N-linked glycans as far as we know, we assayed the prostate gland of L. stagnalis for a potential glucosyltransferase activity involved in the biosynthesis of such structures. We report here, that the prostate gland of L. stagnalis contains a beta1-->4-glucosyltransferase activity that transfers glucose from UDP-glucose to acceptor substrates carrying a terminal N-acetylglucosamine. The enzyme prefers substrates carrying a terminal GlcNAc that is beta6 linked to a Gal or a GalNAc, structures occurring in O-linked glycans, or a GlcNAc that is beta2 linked to mannose, as is present in N-linked glycans. Based on combined structural and enzymatic data, we propose that the novel beta1-->4-gluco-syltransferase present in the prostate gland may be involved in the biosynthesis of Glcbeta1-->4GlcNAc units in complex-type glycans, in particular in N-linked diantennary glycans.     

Recurrent long-lasting tethering reduces BDNF protein levels in the dorsal hippocampus and frontal cortex in pigs

Brain-derived neurotrophic factor (BDNF) signaling has been implicated in the onset of depression and in antidepressant efficacy, although the exact role of this neurotrophin in the pathophysiology of depression remains to be elucidated. Also, the interaction between chronic stress, which may precede depression, corticosteroids and BDNF is not fully understood. The present study aimed at investigating whether long-lasting, recurrent tethering of sows during a period of 1.5 or 4.5 years leads to enduring effects on measures that may be indicative of chronic stress, compared with animals kept in a group housing system ('loose' sows). Immediately after slaughter, the frontal cortex, dorsal and ventral hippocampus were dissected and protein levels of BDNF and its receptors were analyzed and compared with plasma cortisol levels and adrenal weights. Results indicate that tethering stress reduced BDNF protein levels in the dorsal hippocampus and the frontal cortex, but not in the ventral hippocampus. In addition, levels of TrkB, the high affinity receptor for BDNF, were increased in the dorsal hippocampus. Plasma cortisol levels and adrenal weight were increased after tethering. These stress effects on BDNF levels were more pronounced after 4.5 years of recurrent tethering and negatively correlated in particular in the frontal cortex with cortisol levels and adrenal weight. This suggests that the stress effect of tethered housing on neurotrophin levels may be mediated via cortisol. Taken together, these data indicate that recurrent tethering stress in sows over 4.5 years results in a loss of neurotrophic support by BDNF, mediated by an overactive neuroendocrine system.     

Drug therapy: dose-response relationship of oral mesalazine in inflammatory bowel disease.

Mesalazine is widely used in the treatment of inflammatory bowel disease. Little is known about the dose-response relationship and about possible dose related side effects. In ulcerative colitis higher dosages of mesalazine (3 g) are more effective in maintaining a remission than lower dosages (1.5 g). In mild to moderately active ulcerative colitis, studies also indicate that higher dosages might be more effective in inducing remission. Dose-comparing studies in Crohn''s disease are even more sparse, but the available results indicate higher efficacy at higher dose levels. None of the known side effects of mesalazine are clearly dose-related. A pH-dependent release system, however, can cause a sudden release of high doses of mesalazine. Consequent peak levels in serum have been implicated in mesalazine induced nephrotoxicity. In conclusion, despite the current practice of using increasing dosages of mesalazine in inflammatory bowel disease, both efficacy and safety have been established tentatively.     

A kinetic study of the soluble 5''-nucleotidase of rat liver.

1. The kinetic properties of the 5'-nucleotidase (EC 3.1.3.5) present in the cytosol of rat liver were investigated in relation to the conversion of adenine nucleotides into uric acid, with particular reference to the stimulation of this process by fructose. The enzyme was assayed by the release of Pi and by a new and more sensitive radiochemical procedure. 2. When IMP was used as substrate, the partially purified enzyme displayed almost hyperbolic kinetics (h = 1.1) with S0.5 = 1.2 mM. Similar kinetics were observed with GMP and other nucleoside 5'-monophosphates, except AMP. 3. Vmax. of the enzyme for AMP was about the same as for IMP, but the kinetics were sigmoidal (h = 1.6) with S 0.5 = 10 mM. 4. The hydrolysis of IMP was inhibited competitively by GMP. IMP, at concentrations up to 0.5 mM, had a paradoxical stimulatory action on the hydrolysis of 2-5 mM-AMP and was inhibitory at higher concentrations. 5. The activity of the enzyme towards AMP and IMP was stimulated by ATP and GTP, and inhibited by Pi. Activators and inhibitor approximately cancelled each others' effects. At pH 7.4, the enzymic activity with 0.2 mM-AMP was undetectable under physiological conditions. 6. It is concluded that, in the liver cell, AMP is not hydrolysed by the soluble 5'-nucleotidase, but that its degradation requires prior deamination to IMP.     

Familial occurrence of severe ulnar aplasia and lobster claw feet: A new syndrome

Summary In this paper we describe a previously unreported association of ulnar defect and lobster-claw deformity of the feet, occurring in four males belonging to two generations of the same family. Minor expression of the same ulnar reduction defect in female relatives suggests X-linked recessive inheritance, but an autosomal dominant with irregular expression cannot be excluded.Aspirant N.F.W.O.     

The barbs (Barbus spp.) of Lake Tana: a forgotten species flock?

Synopsis All living species occupy an ecological niche, and are positioned within a trophic hierarchy. Extinct organisms presumably held similar behavioral and coevolutionary characteristics in the past, and were susceptible to the same kinds of natural ecological pressures operating today. Paleoecological investigations are limited by the incompleteness of the fossil record, and particularly by a lack of behavioral data that are so fundamental to ecological studies of living communities and habitats. Opportunities to examine the coevolutionary structure of ancient communities from empirical data are extremely rare. One such opportunity is provided by the Lower Cretaceous Santana Formation of north-eastern Brazil, a series of richly fossiliferous strata approximately 110 million years old. Many fossil fishes from the Santana Formation contain identifiable prey, including decapod crustaceans and fishes. A trophic hierarchy of these organisms is reconstructed here, and their ecological relationships are discussed. Comparison is made with a similar fish fauna from the Upper Jurassic Solnhofen Limestone of Germany. Low-level, intermediate and high-level predators are identified in each fauna. Predator-prey relationships in the Santana fauna are strongly hierarchical, and are more focussed at the intermediate predator level than in Solnhofen. Comparison with a model of predator-prey relationships between fishes and benthic fauna of the Baltic Sea (which like the Araripe Basin represents a semi-enclosed environment) suggests that heavy predation on teleosts such asRhacolepis, occupying an intermediate trophic level, may have permitted benthic decapods to proliferate and exclude other benthic organisms. Less intense predation on fishes at the intermediate trophic level would allow their numbers to increase, thereby increasing the intensity of predation on the benthos at the base of the trophic hierarchy.     

Substrate specificity in the highly heterogeneous M4 peptidase family is determined by a small subset of amino acids

The members of the M4 peptidase family are involved in processes as diverse as pathogenicity and industrial applications. For the first time a number of M4 family members, also known as thermolysin-like proteases, has been characterized with an identical substrate set and a uniform set of assay conditions. Characterization with peptide substrates as well as high performance liquid chromatography analysis of beta-casein digests shows that the M4 family is a homogeneous family in terms of catalysis, even though there is a significant degree of amino acid sequence variation. The results of this study show that differences in substrate specificity within the M4 family do not correlate with overall sequence differences but depend on a small number of identifiable amino acids. Indeed, molecular modeling followed by site-directed mutagenesis of one of the substrate binding pocket residues of the thermolysin-like proteases of Bacillus stearothermophilus converted the catalytic characteristics of this variant into that of thermolysin.     

Incomplete Restoration of Angiotensin II - Induced Renal Extracellular Matrix Deposition and Inflammation Despite Complete Functional Recovery in Rats

Some diseases associated with a temporary deterioration in kidney function and/or development of proteinuria show an apparently complete functional remission once the initiating trigger is removed. While it was earlier thought that a transient impairment of kidney function is harmless, accumulating evidence now suggests that these patients are more prone to developing renal failure later in life. We therefore sought to investigate to what extent renal functional changes, inflammation and collagen deposition are reversible after cessation of disease induction, potentially explaining residual sensitivity to damage. Using a rat model of Angiotensin II (Ang II)-induced hypertensive renal disease we show the development of severe hypertension (212 ± 10.43 vs. 146 ± 1.4 mmHg, p<0.001) and proteinuria (51.4 ± 6.3 vs. 14.7 ± 2.0 mg/24h, p<0.01) with declined creatinine clearance (2.0 ± 0.5 vs. 4.9 ± 0.6 mL/min, p<0.001) to occur after 3 weeks of Ang II infusion. At the structural level, Ang II infusion resulted in interstitial inflammation (18.8 ± 4.8 vs. 3.6 ± 0.5 number of macrophages, p<0.001), renal interstitial collagen deposition and lymphangiogenesis (4.1 ± 0.4 vs. 2.2 ± 0.4 number of lymph vessels, p<0.01). Eight weeks after cessation of Ang II, all clinical parameters, pre-fibrotic changes such as myofibroblast transformation and increase in lymph vessel number (lymphangiogenesis) returned to control values. However, glomerular desmin expression, glomerular and periglomerular macrophages and interstitial collagens remained elevated. These dormant abnormalities indicate that after transient renal function decline, inflammation and collagen deposition may persist despite normalization of the initiating pathophysiological stimulus perhaps rendering the kidney more vulnerable to further damage.     

Human-induced hybridization among congeneric endemic plants on Tenerife, Canary Islands

Endemic genera on oceanic islands often evolved striking morphological and ecological differences among species, with weak postzygotic reproductive isolation. Human activities can lead to increased connectivity and can thereby promote secondary contact and hybridization between previously isolated species. We studied this phenomenon in three species of the genus Pericallis (Asteraceae) on Tenerife, Canary Islands. A total of 53 populations was sampled, including morphologically uniform as well as mixed populations containing morphologically diverse individuals. All plants were analyzed both genetically using AFLP markers and morphometrically. As expected, morphological analysis clearly separated the plants from the uniform populations in three clusters, with distinguishing characters corresponding to those used in species identification. The three species were also grouped into distinct genetic clusters in a structure analysis, although no private alleles were observed. Adding the mixed population data to the analyses provided evidence for extensive hybridization among species, predominantly between P. cruenta and P. echinata, and between P. cruenta and P. tussilaginis, and morphological and genetic signals were congruent. The mixed populations were geographically located in between the uniform populations and were found in road verges significantly more often than the uniform populations. The observed distribution strongly suggests that hybridization between originally isolated species is recent, promoted by secondary contact due to human disturbance and the construction of roads.