Applications of Hydrolytic and Decarboxylating Enzymes in Biotransformations

Peptides, and oligosaccharides and glycosides, can be synthesised by making use of the ‘reverse hydrolytic activity’ of proteases and glycosidases respectively. In applying these enzymes to the practical synthesis of these classes of compound, several factors need to be considered, namely the need to shift the rate-determining step through the use of activated substrates, the need to minimise competing hydrolysis of these and the need to minimise hydrolysis of the products. In spite of these problems, the enzymatic methods have many attractive features, not least amongst which is the absolute control of stereochemistry in acyl transfer and glycosyl transfer respectively.     

Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples

In this study, we evaluated several techniques for the detection of the yeast form of Cryptococcus in decaying wood and measured the viability of these fungi in environmental samples stored in the laboratory. Samples were collected from a tree known to be positive for Cryptococcus and were each inoculated on 10 Niger seed agar (NSA) plates. The conventional technique (CT) yielded a greater number of positive samples and indicated a higher fungal density [in colony forming units per gram of wood (CFU.g^-1) ] compared to the humid swab technique (ST). However, the difference in positive and false negative results between the CT-ST was not significant. The threshold of detection for the CT was 0.05.10³ CFU.g^-1, while the threshold for the ST was greater than 0.1.10³ CFU^-1. No colonies were recovered using the dry swab technique. We also determined the viability of Cryptococcus in wood samples stored for 45 days at 25ºC using the CT and ST and found that samples not only continued to yield a positive response, but also exhibited an increase in CFU.g^-1, suggesting that Cryptococcus is able to grow in stored environmental samples. The ST.1, in which samples collected with swabs were immediately plated on NSA medium, was more efficient and less laborious than either the CT or ST and required approximately 10 min to perform; however, additional studies are needed to validate this technique.     

Wood preservation hygiene and environment in the lime-light of actually

Summary Under the ?Bois plus? scheme, the CTBA is currently developing a third party certification, based on the Scrivener law, with the aim of defending the consumers' interests. At this early stage, wood preservatives and treated wood are checked for the efficacy of treatments in order to ensure the stability and security of works in buildings and civil engineering. According to the different classes of risks in service, ?Bois plus? provides the most adeguate level of protection. In the close future, the industry is planning to incorporate, with the help of the CTBA and experts, health criteria within the frame of the ?Bois plus? certification scheme. The means could beSafety indexes, which are objectives of quality for professionals.Safety indexes are concentrations of substances in wood which can be taken as safe for humans and the general environment, while still toxic for the wood pests. This attractive experience aims to make with the brandname ?Bois plus? a synonym of efficacy and safety. This approach meets the essential requirements 1, 3, 4 of the 89/106 EEC directive: mechanical resistance and stability/hygiene, health and environment/safety in use.     

Development of Bursaphelenchus xylophilus Populations in Wood Chips with Different Moisture Contents

Bags of Pinus strobus wood chips with moisture contents of 38, 92, 164, and 217% (oven dry weight) were inoculated with Bursaphelenchus xylophilus and incubated at 30 C in order to determine the effect of wood moisture on nematode population development. Nematodes were extracted after 2, 4, 8, and 12 weeks. Population levels were greatest in wood chips with a moisture content of 38% and decreased successively with each higher moisture content. In chips with the three lower moisture contents, populations peaked at 2 weeks, but at 217% moisture, they peaked at 8 weeks. By 12 weeks, nematode populations had declined in wood chips with 92 and 164% moisture contents. The fungi most frequently isolated from the wood chips were Alternaria, Fusarium, Gliocladium, Graphium, Penicillium, Trichoderma, and Mucorales.     

Wood distillate (pyroligneous acid) boosts nutritional traits of potato tubers

Potato is the fourth most widely consumed staple food in the world. This study investigated the effectiveness of 0.2% wood distillate (WD), a biostimulant derived from the pyrolysis of waste plant biomass, in boosting the nutritional quality of potato tubers. The results showed that application of WD significantly increased the content of soluble sugars (sucrose +56.3%; glucose +44.9%; fructose +62.2%), starch (+35.1%) and total carbohydrates (+16.8%). Antioxidants (total antioxidant power, polyphenols, flavonoids) and most mineral elements (K, Mg, Ca, Na, Fe, Zn) were not affected. A lower content of Cu (−17.8%) and P (−24.5%) was found in WD-treated potato.     

DIGESTION SURVIVAL OF ALGAE: SOME ECOLOGICAL COMPARISIONS BETWEEN FREE SPORES AND PROPAGULES IN FECAL PELLETS1

Benthic algae survive passage through the digestive tract of different types of grazers, either regenerating new tissues or releasing protoplasts and swarmers which act as accessory means of reproduction to generate new individuals. The ecological importance of this phenomenon is evaluated here by studying spores and fecal pellets. Alga fragments egested alive inside fecal pellets have some ecological advantages over free propagules. In intertidal habitats, the sticky nature of the pellets permits attachment to the substratum while protecting the contained algae from desiccation. In subtidal habitats, the pellets sink 8–22 times faster than the fastest sinking algal propagule. Quantification of swarmers and protoplasts released from algal fragments in the fecal pellets indicates densities of about 217 germlings·cm^?2 and values of 300–700 propagules per pellet. Extrapolation of these results to field conditions based on number of grazers and pellets suggest production figures varying from 0.5–3.5 × 10⁵to 1.3–1.5 × 10⁶ propagules·m^?2·12 h^?1. These values are within known density ranges of settling spores in the field. The ecological significance of the phenomenon may be especially important at seasons when the density of grazers increases and the normal reproductive activity of the algae being consumed decreases.     

The relationships between brain, serum, and whole blood ChE activity in the wood mouse (Apodemus sylvaticus) and the common shrew (Sorex araneus) after acute sublethal exposure to dimethoate

Inhibition of cholinesterase (ChE) activity produced by a single acute intraperitoneal administration of dimethoate was studied in the wood mouse, Apodemus sylvaticus, and the common shrew, Sorex araneus, under laboratory conditions. ChE values from serum and whole blood were compared with those obtained from brain in order to obtain a non-destructive tool for predicting the severity of brain acetylcholinesterase (AChE) inhibition. In addition, serum and brain inhibition following oral exposure to dimethoate was also measured in the wood mouse. Normal ChE activity was higher in the brain and whole blood of the shrews than in wood mice. There was no difference between species in serum ChE activity. Exposure to dimethoate caused a dose-dependent reduction in ChE activity and there was a significant recovery in activity with increasing time after administration. In both species, serum and whole blood were more sensitive than brain for revealing organophosphate-induced ChE inhibition and serum was more sensitive than whole blood. Statistically significant relationships were defined between whole blood and brain ChE activity and between serum and brain ChE activity. Compared with serum, whole blood ChE activity was the more accurate predictor of brain AChE levels. The relationships between brain and serum ChE activity did not appear to be affected by the route of administration of the pesticide.