An improved algorithm for fast resonant Mie scatter correction of infrared spectra of cells and tissues

Mie scattering effects create serious problems for the interpretation of Fourier‐transform infrared spectroscopy spectra of single cells and tissues. During recent years, different techniques were proposed to retrieve pure absorbance spectra from spectra with Mie distortions. Recently, we published an iterative algorithm for correcting Mie scattering in spectra of single cells and tissues, which we called “the fast resonant Mie scatter correction algorithm.” The algorithm is based on extended multiplicative signal correction (EMSC) and employs a meta‐model for a parameter range of refractive index and size parameters. In the present study, we suggest several improvements of the algorithm. We demonstrate that the improved algorithm reestablishes chemical features of the measured spectra, and show that it tends away from the reference spectrum employed in the EMSC. We suggest strategies for choosing parameter ranges and other model parameters such as the number of principal components of the meta‐model and the number of iterations. We demonstrate that the suggested algorithm optimizes an error function of the refractive index in a forward Mie model. We suggest a stop criterion for the iterative algorithm based on the error function of the forward model.      

What Was Socialism, and What Comes Next?

What Was Socialism, and What Comes Next? Katherine Verdery. Princeton, NJ: Princeton University Press, 1996. 298 pp.     

Provocations of European Ethnology

What is the relevance of Europeanist ethnography for anthropological theory generally? Considering a region usually regarded as the source rather than an object of anthropology and colonialism alike, seven anthropologists reflexively address, inter alia, the implications of studying spaces already deeply explored by other disciplines, the potential of economic history to defamiliarize Eurocentric models and of recent events to illuminate such concepts as state and market, the meaning of "West" as a specific locus of power and reification, the limits of the "local" as the focus of ethnography, and the tensions among politically and culturally disparate entities within emergent ideologies of cultural unity.     

Cleavage of chitinous elicitors from the ectomycorrhizal fungus Hebeloma crustuliniforme by host chitinases prevents induction of K+ and Cl− release, extracellular alkalinization and H2O2 synthesis of Picea abies cells

Rapid reactions comprising efflux of K⁺ and Cl⁻, phosphorylation of a 63-kDa protein (pp63), extracellular alkalinization and synthesis of H₂O₂ are equally induced in cells of Picea abies (L.) Karst. by chitotetraose, colloidal chitin and cell wall elicitors from the ectomycorrhizal fungus Hebeloma crustuliniforme (Bull. ex Fries.) Quél. an ectomycorrhizal partner of spruce. Cleavage of fungal cell wall elicitors and of artificial chitin elicitors to monomeric and dimeric fragments by apoplasmic spruce chitinases (36-kDa class I chitinase, pI 8.0, and 28-kDa chitinase, pI 8.7; EC 3.2.1.14) equally prevented induction of these rapid reactions. Also, N-acetylglucosamine oligomers and elicitors from the fungal cell walls showed a similar dependence of their activity on the degree of polymerisation. From these results it is suggested that, during ectomycorrhiza formation, only some of the chitin-derived elicitors reach their receptors at the plant plasma membrane, initiating reactions of the hypersensitive response in the host cells. The remaining fungal elicitors will be degraded to varying extents by wall-localized chitinases of the host root, reducing the defence reactions of the plant and allowing symbiotic interactions of both organisms. Received: 6 January 1997 / Accepted: 14 March 1997     

Temperature effects on chemical signalling in a predator–prey system

SUMMARY 1. We investigated the effect of temperature on chemical signalling in a predator–prey model system (planktivorous fish and Daphnia galeata ). Life-history changes in Daphnia in response to chemical cues (kairomones) derived from fish have become a paradigm for chemically induced anti-predator defences.
2. As temperature can affect both predator and prey, we carried out two experiments to disentangle these effects. In order to test for temperature effects on the predator, we kept prey at a single temperature and exposed them to kairomones from fish exposed to two different temperatures. Daphnia exhibited a higher intrinsic rate of population increase ( r ) when exposed to fish kairomones produced at high rather than low temperature. Assuming a positive correlation between r (because of an earlier maturation and/or increased clutch sizes) and kairomone concentration, our results suggest that kairomone production increases with rising temperature.
3. In the second experiment, to study the influence of temperature on the prey, Daphnia were kept at two different temperatures and exposed to fish kairomones produced at one constant temperature. We found no interaction between the effects of fish kairomone and temperature on Daphnia life history, suggesting that temperature does not directly alter life-history responses to fish kairomones.
4. Our results suggest that temperature influences Daphnia life history through its effects on fish kairomone concentration, but that temperature does not affect the strength of the response of Daphnia to the presence of fish.     

Cloning and characterization of the mammalian-specific nicolin 1 gene (NICN1) encoding a nuclear 24 kDa protein.

We have identified a novel mammalian gene, termed nicolin 1 gene (NICN1), that is present in human, dog and mouse, whereas it is absent from the available genome sequences of nonmammalian organisms. The NICN1 gene consists of six exons and spans about 6 kb of genomic DNA. It encodes a 213 amino acid protein that does not belong to any known protein family. Experiments using green fluorescent protein (GFP)-tagged nicolin 1 fusion proteins indicate that nicolin 1 is a nuclear protein. Northern analysis and semiquantitative RT-PCR demonstrated that the 2.5 kb NICN1 mRNA is expressed in a tissue-specific manner. The highest NICN1 expression levels are found in brain, testis, liver, and kidney. On the other hand the NICN1 expression is weak in spleen, leukocytes, small intestine and colon. The NICN1 gene is also expressed during development.     

Soluble signalling factors derived from differentiated cartilage tissue affect chondrogenic differentiation of rat adult marrow stromal cells.

BACKGROUND: Chondral defects show lack of proper regeneration whereas osteochondral lesions display limited regeneration capacity. Latter is probably due to immigration of chondroprogenitor cells from the subchondral bone. Known chondroprogenitor cells for cartilage tissues are multi-potent adult marrow stromal or mesenchymal stem cells (MSCs). In vitro chondrogenic differentiation of these precursor cells usually require cues from growth and signalling factors provided in vivo by surrounding tissues and cells. We hypothesise that signalling factors secreted by differentiated cartilage tissue can initiate and maintain chondrogenic differentiation status of MSCs. METHODS: To study such paracrine communication between allogenic rat articular cartilage and rat MSCs embedded in alginate beads a novel coculture system without addition of external growth factors has been established. RESULTS: Impact of cartilage on differentiating MSCs was observed at two different time points. Firstly, sustained expression of Sox9 was observed at an early stage which indicated induction of chondrogenic differentiation. Secondly, late stage repression of collagen X indicated pre-hypertrophic arrest of differentiation. In the culture supernatant we have identified vascular endothelial growth factor alpha (VEGF-164 alpha), matrix metalloproteinase (MMP) -13 and tissue inhibitors of MMPs (TIMP-1 and TIMP-2) which could be traced back either to the cartilage explant or to the MSCs under the influence of cartilage. CONCLUSION: The identified factors might be involved in regulation of collagen X gene and protein expression and therefore, may have an impact on the control and regulation of MSCs differentiation.     

Der Serotoninstoffwechsel in einzelnen Hirnteilen vom Tupaia (Tupaia belangeri) bei soziopsychischem Stress

Zusammenfassung Bei sozialem Stress nehmen die Konzentrationen von Serotonin (5-HT) und 5-Hydroxyindolessigsäure (5-HIAA) in den einzelnen Hirnteilen von Tupaias zu. Diese Zunahme läßt sich durch eine erhöhte Stoffwechselgeschwindigkeit (turnover) erklären.Die Änderungen in der Stoffwechselgeschwindigkeit der einzelnen Hirnteile hängen von der Art der sozialen Belastung ab.Schon Kampf mit Unterwerfung (zweimal täglich) führt zu einem schnelleren Stoffwechsel des 5-HT in allen Hirnteilen. Belastet man die Tiere außer durch Kampf noch dadurch, daß sie das Tier, das sie besiegt hat, zwischen den Kampfpausen sehen können, so wird der Stoffwechsel des 5-HT in einzelnen Hirnteilen (Septum, Frontaler Cortex) nochmals erhöht.Eine mögliche funktioneile Bedeutung dieser Veränderungen wurde diskutiert.

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Serotonin metabolism in discrete brain areas and sociopsychic stress in tupaia (Tupaia belangeri)

Summary The physiological state of the animals depends not only on ecological factors. It is also determined by the social interactions of the animals. Some of these social interactions are harmful to the physiological state of the individuals. The aim of this work was to separate the physical loads of social interactions from the mere psychic ones and to correlate them with neurochemical changes. For this purpose the concentration levels of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were measured in discrete brain areas.To separate the psychic from the physical loads male tupaias (Tupaia belangeri) were exposed two times a day (at 9.30 and 13.30 h) for two minutes to the attacks of an experienced fighter. The animals were defeated during these attacks. One group of the defeated animals was in optical contact with the experienced fighter throughout the day (12 hours; Stresstiere). The other group of the defeated animals was optically separated from the experienced fighter after each fight (Kampftiere).After four days the animals were decapitated at 15.00 h, 5.5 hours after the last fight (on the fourth day the animals were not allowed to fight at 13.30 h). Animals which had not fought were decapitated at the same time and served as controls. 5-HT and 5-HIAA levels were estimated within two days after decapitation.During the test the animals lose body weight. Animals who are only exposed to attacks (Kampftiere) loose 2.8±2.8%; animals who are exposed to attacks and optical contact with the experienced fighter (Stresstiere) lose 11.8±3.4%.The concentration levels of 5-HT and 5-HIAA in both groups are elevated compared with controls. This fact indicates a higher turnover of these substances. The concentration levels are most elevated in parts of the brain of defeated animals exposed to continuous optical contact with the experienced fighter (Stresstiere). These differences are most prominent in the septum and the frontal cortex (s. p. 60).A model for the physiological meaning of these changes is discussed. It was assumed that the activity of the brain is controlled by a system which is functionally analogous to the peripheral autonomous nervous system. 5-HT and norepinephrine should act on antagonistic branches of such a system in central nervous system. Under stress conditions the activity of both branches should be enhanced.

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Herrn Prof. Dr. H. Autrum möchte ich für die Überlassung des Themas, für sein stetes Interesse und anregende Diskussionen danken. Die Untersuchungen wurden durch Sachbeihilfen gefördert, die die Deutsche Forschungsgemeinschaft Herrn Prof. Dr. H. Autrum zur Verfügung stellte.

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Der Firma Sharp & Dohme GmbH danke ich für die kostenlose Überlassung von 15 g Probenecid.     

Social Stressors at Work,Sleep, and Recovery

Many employees in service work are required to work on Saturdays, recovering during work-free Sundays and working again Mondays. We examined the effects of social stressors at work on recovery status at Sunday noon and Monday noon, and investigated if sleep quality mediates the negative effects of social stressors at work on recovery. From Saturday until Monday morning, 41 participants wore actigraphs to measure sleep duration and sleep fragmentation. Social stressors at work were assessed by self-reported questionnaires administered on Saturday. Recovery status was reported Sunday noon and Monday noon. Hierarchical regression analysis revealed that social stressors at work were negatively related to recovery status on Sunday and on Monday. Supporting our assumptions, more social stressors at work predicted higher sleep fragmentation in the night to Monday. A mediation effect of sleep quality, however, was not found. Theoretical and practical implications of these results are discussed.     

Mitochondrial coenzyme Q content and aging.

The main objective of this study was to determine the nature of the relationship between aging and mitochondrial coenzyme Q (CoQ) content. Mitochondria in the heart, skeletal muscle, kidney and brain of the mouse varied in both the amount of total CoQ (CoQ9 + CoQ10) content as well as in the ratio of the CoQ9 to CoQ10. CoQ content declined with age only in the skeletal muscle. Caloric restriction (CR) resulted in an increase in the amount of CoQ9 in skeletal muscle mitochondria. This effect was partially reversible upon termination of the caloric restriction regimen. Results suggest that a decrease in mitochondrial CoQ content is an integral aspect of aging in skeletal muscle.