Thermoplastic starch modification during melt processing: Hydrolysis catalyzed by carboxylic acids

The melt processing of glycerol-plasticized starch in the presence of non-volatile carboxylic acids resulted in a progressive loss of its molar mass, because the residual moisture in the mixture induced an acid-catalyzed hydrolysis of the ether linkages in its polysaccharide chains. The study of this reaction provided a useful means of adjusting its course and thus of preparing starch materials with controlled properties.     

Applications of ATR-FTIR spectroscopic imaging to biomedical samples

FTIR spectroscopic imaging in ATR (Attenuated Total Reflection) mode is a powerful tool for studying biomedical samples. This paper summarises recent advances in the applications of ATR-FTIR imaging to dissolution of pharmaceutical formulations and drug release. The use of two different ATR accessories to obtain chemical images of formulations in contact with water as a function of time is demonstrated. The innovative use of the diamond ATR accessory allowed in situ imaging of tablet compaction and dissolution. ATR-FTIR imaging was also applied to obtain images of the surface of skin and the spatial distribution of protein and lipid rich domains was obtained. Chemical images of cross-section of rabbit aorta were obtained using a diamond ATR accessory and the possibility of in situ imaging of arterial samples in contact with aqueous solution was demonstrated for the first time. This experiment opens an opportunity to image arterial samples in contact with solutions containing drug molecules. This approach may help in understanding the mechanisms of treatment of atherosclerosis.     

Foraging behaviour of the Brazilian squirrelSciurus aestuans (Rodentia, Sciuridae)

We describe the foraging behaviour of the Brazilian squirrelSciurus aestuans Linnaeus, 1776 in a natural free-living population, in an area with a high concentration of palm fruitsSyagrus romanzoffiana (Chamisso) Glassman. Our objective was to investigate if the abundance ofS. romanzoffiana fruits, an important food item for squirrels, temporally influenced the foraging behaviour of this population. The observations were carried out over an eight-month (April–November 2001) period. Fruiting phenology ofS. romanzoffiana was also monitored. The most consumed food item for this period was the fruit ofS. romanzoffiana (70%), followed by foods of human origin (14%). The percentage of time spent feeding increased in September, and the time spent travelling declined in September, October and November, when females were observed showing evidence of reproductive activity. At the same timeS. romanzoffiana fruits become available. The consumption of human items illustrates the opportunistic feeding habit of these squirrels, but variations in foraging behaviour detected probably were more strongly related to availability ofS. romanzoffiana fruits.     

Effects of successive seasons of genetically modified herbicide-tolerant maize cropping on weeds and invertebrates

The use of genetically modified herbicide‐tolerant (GMHT) crops influences the abundance of weeds and some invertebrate groups because the associated herbicide regime contrasts with that of conventional systems. However, it is not clear to what extent these effects might be cumulative; should GMHT crops be grown continuously. In northern Europe, in the near future, this situation is most likely to apply to maize crops. Here, we consider the effects of continuous GMHT maize cropping on plant and invertebrate taxa using a split‐field experiment. Half of each field was managed using GMHT and the other half with a conventional variety, with the treatments retained for two seasons. The treatment effects were broadly consistent with those found in the larger sample of non‐continuous maize sites within the Farm Scale Evaluations. There was little evidence of effects being significantly more pronounced in the second year; any cumulative differences in above‐ground biodiversity between GMHT and conventional cropping were too variable to be readily detected.     

Distribution of intracellular fucoidan hydrolases among marine bacteria of the family Flavobacteriaceae

A search for fucoidan-degrading enzymes and other O-glycosylhydrolases has been performed among 51 strains of marine bacteria of the family Flavobacteriaceae isolated from red, green, and brown algae, as well as from the sea urchin Strongylocentrotus intermedius and the holothurian Apostichopus japonicus. Over 40% of the studied strains synthesized fucoidanases. The marine bacteria Mesonia algae KMM 3909^T (an isolate from green alga Acrosiphonia sonderi), as well as Maribacter sp. KMM 6211 and Gramella sp. KMM 6054 (associants of the sea urchin S. intermedius), were the best producers of fucoidanases. Xylose effectively induced the biosynthesis of fucoidanases in these strains. None of the 15 strains of marine bacteria belonging to the genus Arenibacter produced polysaccharide hydrolases.     

Synthesis and properties of horseradish peroxidase copolymers

Conditions for copolymerization of native and sodium periodate-oxidized horseradish peroxidase (HTP; EC 1.11.1.7) have been optimized. Copolymerization products have been characterized electrophoretically, spectrally, and kinetically. Copolymers containing 2–3, 4, 5–7, and 9–10 molecules of the enzyme were found among the products of polymerization. The copolymers had lower values of D ₄₀₃/D ₂₈₀ than HRP. The copolymers had more ordered structures than the original HRP. Comparison of the thermal stability and kinetic characteristics of the fractions differing in the ratio of copolymers to the monomeric enzyme demonstrated that the polymeric products were more stable than HRP (in terms of resistance to high temperature or inhibitory effects of H₂O₂), but their kinetic activity was, on the whole, lower than that of the original enzyme.     

Diversity and Distribution of Planctomycetes and Related Bacteria in the Suboxic Zone of the Black Sea

Samples from six depths of the Black Sea's suboxic zone were analyzed for 16S rRNA gene sequence information. A gradient in phylotype diversity was found. The distributions of known anaerobic ammonium oxidation (anammox) bacteria, many unknown Planctomycetes, and other phylotypes were examined in relation to the local nutrient and redox conditions.