Biosynthetische Produktion von humanidentischer Polysialinsäure in Escherichia coli K1

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Genetics of melanoma progression: the rise and fall of cell senescence.

There are many links between cell senescence and the genetics of melanoma, meaning both familial susceptibility and somatic-genetic changes in sporadic melanoma. For example, CDKN2A, the best-known melanoma susceptibility gene, encodes two effectors of cell senescence, while other familial melanoma genes are related to telomeres and their maintenance. This article aimed to analyze our current knowledge of the genetic or epigenetic driver changes necessary to generate a cutaneous metastatic melanoma, the commonest order in which these occur, and the relation of these changes to the biology and pathology of melanoma progression. Emphasis is laid on the role of cell senescence and the escape from senescence leading to cellular immortality, the ability to divide indefinitely

Monitoring the influence of different weathering conditions on polyethylene pipes by IR-microscopy

Plastic pipes are often exposed to a range of environmental conditions which may lead to their degradation. The most important influence factors are UV radiation, humidity and temperature. These can cause leaching of long-term and light stabilisers and finally oxidation of the polymer. In this study we demonstrate how the elemental steps of the photooxidative degradation of polyethylene pipes can be monitored by IR-microscopy. In detail the influence of UV radiation leads to a depletion of the phenolic long-term stabiliser, Irganox 1010. Calibration of the spectroscopic data enables IR-microscopy to be carried out in a quantitative manner and the rate constants for the stabiliser loss to be calculated for the first time. The results obtained from IR-microscopy are well in agreement with those obtained by mechanical sample preparation and measurement of the oxidative induction time (OIT) as well as extraction coupled with chromatographic analysis (HPLC). A mechanism based on Norrish type cleavage is proposed. Also the formation of trans-vinylidene groups as unsaturated degradation products of the PE can be observed. In summary it can be shown that IR-microscopy is highly superior to the conventional approach of mechanical sample preparation with regard to spatial resolution and offers the advantage of being less labour intensive

Population monitoring of snow leopards using camera trapping in Naryn State Nature Reserve, Kyrgyzstan, between 2016 and 2019

International audienceHighlights:• Citizen science is a useful tool for monitoring snow leopard (Panthera uncia) populations over long periods of time.• Naryn State Nature reserve hosts a breeding population of at least 5 snow leopards with a balanced sex ratio along the study.• Snow leopards territories overlaps regardless of their sex in Naryn State Nature reserve.• Significant snow leopard presence at the edge and buffer zone of the reserve advocates for extending the core reserve limits.Abstract:Four field seasons of snow leopard (Panthera uncia) camera trapping inside Naryn State Nature Reserve, Kyrgyzstan, performed thanks to citizen science expeditions, allowed detecting a minimal population of five adults, caught every year with an equilibrated sex ratio (1.5:1) and reproduction: five cubs or subadults have been identified from three litters of two different females. Crossings were observed one to three times a year, in front of most camera traps, and several times a month in front of one of them. Overlap of adults' minimal territories was observed in front of several camera traps, regardless of their sex. Significant snow leopard presence was detected in the buffer area and at Ulan area which is situated at the reserve border. To avoid poaching on this apex predator and its preys, extending the more stringent protection measures of the core zone to both the Southern buffer area and land adjacent to Ulan is recommended

Coping mediates the relationship between emotional intelligence (EI) and academic achievement

Research examining the relationships between performance measures of emotional intelligence (EI), coping styles, and academic achievement is sparse. Two studies were designed to redress this imbalance. In each of these studies, both EI and coping styles were significantly related to academic achievement. In Study 1, 159 community college students completed the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) and problem-focused, emotion-focused, and avoidant coping scales. Collectively, the coping variables significantly mediated the relationship between EI and grade-point-average (GPA) for Emotion Perception, Emotion Facilitation of Thought and Emotion Management (but not for Emotional Understanding). Problem-focused coping was the only single significant mediator, mediating the relationship between emotion management and GPA (but not other branches and GPA). In Study 2, 293 middle-school students completed the Situational Test of Emotion Management for Youths (STEM-Y) and scales measuring the same three coping strategies. In this study, the coping variables again significantly mediated the relationship between emotion management and GPA. Once again, problem-focused coping was a significant mediator. Collectively, these results suggest that better educational outcomes might be achieved by targeting skills relating to emotion management and problem-focused coping

Proteolytic Release of the Intramolecular Chaperone Domain Confers Processivity to Endosialidase F*S⃞

Endosialidases (endoNs), as identified so far, are tailspike proteins of bacteriophages that specifically bind and degrade the α2,8-linked polysialic acid (polySia) capsules of their hosts. The crystal structure solved for the catalytic domain of endoN from coliphage K1F (endoNF) revealed a functional trimer. Folding of the catalytic trimer is mediated by an intramolecular C-terminal chaperone domain. Release of the chaperone from the folded protein confers kinetic stability to endoNF. In mutant c(S), the replacement of serine 911 by alanine prevents proteolysis and generates an enzyme that varies in activity from wild type. Using soluble polySia as substrate a 3-times higher activity was detected while evaluation with immobilized polySia revealed a 190-fold reduced activity. Importantly, activity of c(S) did not differ from wild type with tetrameric sialic acid, the minimal endoNF substrate. Furthermore, we show that the presence of the chaperone domain in c(S) destabilizes binding to polySia in a similar way as did selective disruption of a polySia binding site in the stalk domain. The improved catalytic efficiency toward soluble polySia observed in these mutants can be explained by higher dissociation and association probabilities, whereas inversely, an impaired processivity was found. The fact that endoNF is a processive enzyme introduces a new molecular basis to explain capsule degradation by bacteriophages, which until now has been regarded as a result of cooperative interaction of tailspike proteins. Moreover, knowing that release of the chaperone domain confers kinetic stability and processivity, conservation of the proteolytic process can be explained by its importance in phage evolution

Ageing study of different types of long-term pressure tested PE pipes by IR-microscopy

Although the lifetime of plastic pipes is commonly determined by hydrostatic pressure tests which measure the mechanical resistance, thermo-oxidative degradation plays an important role in practice. It is, therefore, an important question to monitor the elemental processes occurring during ageing of polymers, namely the loss of stabilising additives and the degradation of the polymer. The diffusion of the phenolic antioxidant AO-18, the processing stabiliser, and changes in polymer morphology during hydrostatic pressure testing, have been systematically studied for pipes made of PE 80 and PE 100 using infrared microscopy in a quantitative manner. For both materials a parabolic concentration profile of AO-18 develops over the pipe wall upon hydrostatic pressure testing. Under comparable conditions of testing the loss rate was larger for the PE 80 than for the PE 100. An annealing of the polymer occurs upon ageing with a similar increase in degree of crystallinity for bot h materials. However, the PE 100 has an overall higher level of crystallinity, and it may be speculated that this is one of the reasons for the slower loss of antioxidant. The results from IR-microscopy are in excellent agreement with analyses of samples taken over the pipe wall by oxidative induction time (OIT) and extraction HPLC. The conversion of the phosphite additive PS-2 to the corresponding phosphate as a result of oxidation has been quantitatively assessed. The total content of phosphate and phosphite was found to be constant, and almost no extraction is seen before 5000 h. GPC analysis of samples taken proves that no significant reduction in average molar mass of the polymer takes place

Plexiform Atypical Spitz Tumor With Rosette-Like Giant Cells. A Histologic and Immunohistochemical Study on a Case Suggesting Ganglioneuroblastic Differentiation. Review of the Literature and Considerations on Histogenesis.

Spitz nevi, atypical Spitz tumors and Spitzoid melanoma, the three clinicopathologic forms that constitute the spectrum of the Spitz-type melanocytic lesions, share a histologic picture characterized by large spindle and/or epithelioid ganglion-like cells, with various admixtures of multinucleate bizarre cells. This remarkable cytology has always been interpreted as an unusual, as well as unexplained form of atypia. We report a case of atypical Spitz tumor with Homer Wright-like rosettes, a feature characteristic of ganglioneuroblastic proliferation. Furthermore, the ganglion-like cells of the tumor showed basophilic punctuation in the cytoplasm, reminiscent of Nissl substance, and a few cells, whether spindled or epithelioid, were positive to neuron-specific enolase and glial fibrillary acid protein. Based on our findings, we hypothesize that the outstanding similarity of the ganglion-like cells of Spitz tumors to the normal parasympathetic ganglion cells and to the cells of ganglioneuroma and ganglioneuroblastoma may not be fortuitous. Instead, it may represent the expression of a specific pattern of melanocytic differentiation, analogous to the neurotization of common and cellular blue nevi, although in this case, it would privilege the parasympathetic lineage over the Schwannian, perineural, or endoneural pathway. Our hypothesis is supported by the literature reports of rosette formation and frank ganglioneuroblastic differentiation in Spitz tumors and melanoma and by the demonstration that parasympathetic neurons take origin from the same tracts of the neural crest as other neural and melanocytic cells