Transforming Signs. Iconicity and Indexicality in Russian Healing and Magic

In this article, the ethnography of magic and healing in contemporary Russia is analyzed using the basic concepts of Peircian semiotics. Indigenous terms of affliction used in magical diagnostics of misfortunes, as well as pantomimic gestures in hand healing are regarded as iconic and indexical signs. Their mode of signification is pragmatic presentation rather than textual representation, which underlies their capacity to effect transformations in consciousness. It is shown, however, that it is cultural conventions of their symbolic meanings that form these signs as icons and indexes.     

Antibacterial activity of a bacteriocin-like substance produced by Bacillus sp. P34 that targets the bacterial cell envelope

The objective of this study was to investigate the mode of action of BLS P34, a bacteriocin-like substance (BLS) produced by a novel Bacillus sp. strain P34 isolated from the Amazon basin. The effect of the BLS was tested against Listeria monocytogenes, showing a bactericidal effect at 200 AU (activity units) ml⁻¹, while no inhibition of spore outgrowth of Bacillus cereus was observed with a dose of 1,600 AU ml⁻¹. Growth of Escherichia coli and Salmonella Enteritidis was inhibited, but only when the chelating agent EDTA was co-added with the BLS. The effect of BLS P34 on L. monocytogenes was also investigated by Fourier transform infrared spectroscopy. Treated cells showed an important frequency increase in 1,452 and 1,397 cm⁻¹ and decrease in 1,217 and 1,058 cm⁻¹, corresponding assignments of fatty acids and phospholipids. Transmission electron microscopy showed damaged cell envelope and loss of protoplasmic material. BLS P34 was bactericidal to Gram-positive, and also showed inhibitory effect against Gram-negative bacteria. There is evidence that its mode of action corresponds to that of a membrane-active substance. The knowledge about the mode of action of this BLS is essential to determine its effective application as an antimicrobial agent.     

Biochemical characterization and mode of action of a thermostable endoglucanase purified from Thermoascus aurantiacus

A major extracellular endoglucanase purified to homogeneity from Thermoascus aurantiacus had a M(r) of 34 kDa and a pI of 3.7 and was optimally active at 70-80 degrees C and pH 4.0-4.4. It was stable at pH 2.8-6.8 at 50 degrees C for 48 h and maintained its secondary structure and folded conformation up to 70 degrees C at pH 5.0 and 2.8, respectively. A 33-amino acid sequence at the N terminus showed considerable homology with 14 microbial endoglucanases having highly conserved 8 amino acids (positions 10-17) and Gly, Pro, Gly, and Pro at positions 8, 22, 23, and 32, respectively. The enzyme is rich in Asp (15%) and Glu (10%) with a carbohydrate content of 2.7%. Polyclonal antibodies of endoglucanase cross-reacted with their own antigen and with other purified cellulases from T. aurantiacus. The endoglucanase was specific for polymeric substrates with highest activity toward carboxymethyl cellulose followed by barley beta-glucan and lichenan. It preferentially cleaved the internal glycosidic bonds of Glc(n) and MeUmbGlc(n) and possessed an extended substrate-binding site with five subsites. The data indicate that the endoglucanase from T. aurantiacus is a member of glycoside hydrolase family 5.     

Dextran dextrinase and dextran of Gluconobacter oxydans

Certain strains of Gluconobacter oxydans have been known since the 1940s to produce the enzyme dextran dextrinase (DDase; EC2.4.1.2)—a transglucosidase converting maltodextrins into (oligo)dextran. The enzyme catalyses the transfer of an α1,4 linked glucosyl unit from a donor to an acceptor molecule, forming an α1,6 linkage: consecutive glucosyl transfers result in the formation of high molecular weight dextran from maltodextrins. In the early 1990s, the group of K. Yamamoto in Japan revived research on DDase, focussing on the purification and characterisation of the intracellular DDase produced by G. oxydans ATCC 11894. More recently, this was taken further by Y. Suzuki and coworkers, who investigated the properties and kinetics of the extracellular DDase formed by the same strain. Our group further elaborated on fermentation processes to optimise DDase production and dextran formation, DDase characterisation and its use as a biocatalyst, and the physiological link between intracellular and extracellular DDase. Here, we present a condensed overview of the current scientific status and the application potential of G. oxydans DDase and its products, (oligo)dextrans. The production of DDase as well as of dextran is first described via optimised fermentation processes. Specific assays for measuring DDase activity are also outlined. The general characteristics, substrate specificity, and mode of action of DDase as a transglucosidase are described in detail. Two forms of DDase are produced by G. oxydans depending on nutritional fermentation conditions: an intracellular and an extracellular form. The relationship between the two enzyme forms is also discussed. Furthermore, applications of DDase, e.g. production of (oligo)dextran, transglucosylated products and speciality oligosaccharides, are summarized.     

Role of membranes in the activities of antimicrobial cationic peptides

Cationic amphiphilic peptides that are found throughout nature have very broad-spectrum activities against microbes. The initial sites of interaction are with microbial membranes. Although dogma suggests that their lethal action involves disruption of the cytoplasmic membranes, a number of cationic peptides can traverse intact membranes to interact with internal targets.     

Early senescence induced by 2-3H-benzoxazolinone (BOA) in Arabidopsis thaliana

Measurements of chlorophyll a fluorescence, nutrient and trace elements, total protein content and malonyldialdehyde in leaves of Arabidopsis thaliana between 1 and 192 h after treatment with 0, 1 or 3 mM 2-3H-benzoxazolinone (BOA), together with imaging of chlorophyll a fluorescence and of the distributions of hydrogen peroxide and superoxide anion, suggested that the primary phytotoxic action of BOA is the induction of premature senescence, and that oxidative stress is a secondary effect that sets in a day or two later.     

Phenolic glycosides of the Salicaceae and their role as anti-herbivore defenses

Since the 19th century the phytochemistry of the Salicaceae has been systematically investigated, initially for pharmaceutical and later for ecological reasons. The result of these efforts is a rich knowledge about the phenolic components, especially a series of glycosylated and esterified derivatives of salicyl alcohol known as “phenolic glycosides”. These substances have received extensive attention with regard to their part in plant-herbivore interactions. The negative impact of phenolic glycosides on the performance of many generalist herbivores has been reported in numerous studies. Other more specialized feeders are less susceptible and have even been reported to sequester phenolic glycosides for their own defense. In this review, we attempt to summarize our current knowledge about the role of phenolic glycosides in mediating plant-herbivore interactions. As background, we first review what is known about their basic chemistry and occurrence in plants.     

神木“全民免费医疗”的可推广性探讨

神木模式是我国＂全民免费医疗＂的一次创造性探索,虽然它不是真正意义上的全民免费医疗制度,但对比目前新医改推广的＂全民医保＂制度而言,它在解决群众＂看病难、看病贵＂的问题上起到更积极的作用,对全国也起着一定的借鉴意义。